Patent Application
20250087495
The present invention relates to: a composition for forming a metal-containing film that can be used for fine patterning according to a multilayer resist method in a semiconductor device manufacturing process; a patterning process using the composition; and a compound for forming a metal-containing film.
As LSIs advance toward higher integration and higher processing speed, miniaturization of pattern rule is progressing rapidly. As a cutting-edge technology for miniaturization, ArF immersion lithography has been adopted for mass-producing 45-nm node devices and smaller. In addition to ArF immersion exposure, double exposure (double patterning) processes have been put to practical use in generations of 28-nm node devices and smaller, so that the formation of narrow-pitch patterns that exceed the optical limit has also become possible.
Furthermore, in the production of 20-nm node and smaller devices, studies have been carried out on multiple exposure (multi-patterning) processes for forming a pattern with a narrower pitch by repeating exposure and etching three or more times. However, multiple exposure processes have an increased number of steps, and are faced with the situation that costs rise considerably due to degradation in productivity caused by longer time spent in manufacturing and more frequent generation of defects.
In recent years, extreme ultraviolet ray (EUV) lithography with a wavelength of 13.5 nm is attracting attention as an effective technology to replace a combination of ArF immersion lithography and multiple exposure process. By using this technology, it has become possible to form a fine pattern with a half pitch of 25 nm or less in one exposure.
Meanwhile, in EUV lithography, resist materials are strongly required to have higher sensitivity to compensate for insufficient output of a light source. However, increase in shot noise accompanying higher sensitization leads to increase in edge roughness (LER and LWR) of line patterns, and compatibility of higher sensitization and low edge roughness is given as an important problem in EUV lithography.
As an attempt to achieve higher sensitivity of a resist or to lower the influence of shot noise, it has been considered in recent years to use a metal material in a resist material. A compound that contains a metallic element, such as barium, titanium, hafnium, zirconium, or tin, has a higher absorbance of EUV light compared to an organic material that does not contain metal, and improvement of photosensitivity of resists and suppression of the influence of shot noise can be expected. Furthermore, a metal-containing resist pattern is expected to achieve a high-selectivity etching process by combining with an underlayer film made from a non-metal material.
For example, resist materials with added metal salt or organometallic complex disclosed in Patent Documents 1 and 2 or non-chemically amplified resist materials that use nanoparticles of metal oxide disclosed in Patent Documents 3 and 4 are considered.
In particular, molecules containing tin are excellent in the absorption of an electron beam and an extreme ultraviolet ray, and are actively researched. In the case of an organotin polymer, which is one such molecule, alkyl ligand is dissociated by light absorption or secondary electrons produced thereby and a resultant is crosslinked with adjacent chains through an oxo bond, and thus this enables the negative tone patterning which may not be removed by an organic developing solution. This organic tin polymer can improve sensitivity while maintaining a resolution and line edge roughness, but has not yet reached the standards for commercial availability (Patent Document 5). In addition, many problems still remain, such as insufficient storage stability regarding change in resist sensitivity.
To solve the problems, there is also consideration of development of the use of a material containing a metal element, such as titanium, hafnium, zirconium, and tin, for a resist underlayer film. There is no need for the improvement for performance, such as the enhancement of exposure sensitivity and the suppression of change in sensitivity in storage environment, which is an issue in resist materials containing metal. In addition, it may be possible to provide a resist underlayer film excellent in dry etching resistance when the metal element is contained. Patent Document 6 reports that a material containing a Ti compound exhibits excellent dry etching resistance to CHF3/CF4-based gas and CO2/N2-based gas.
On the other hand, filling property is a problem when using a metal compound for a resist underlayer film. Although there is no mention of filling property in Patent Document 6, a metal oxide compound generally undergoes great thermal shrinkage during baking and induces remarkable degradation of filling after baking at a high temperature. Therefore, there is a concern that such a compound is insufficient as a resist underlayer film material for which high planarizing and filling properties and heat resistance are required. Patent Document 7 reports that a metal compound modified with a particular ligand has excellent filling property. However, the baking temperature in the performed filling property evaluation is a low temperature of 150° C., and there is a concern that the compound is insufficient as a resist underlayer film, which requires heat resistance (for example, resistance to a heat treatment that is performed after the formation of a resist underlayer film in some cases). Patent Document 8 provides a resist underlayer film material excellent in filling property after baking at 400° C. by mixing the metal compound reported in Patent Document 7 and an organic polymer having a particular structure. However, since the material is a mixed composition of a metal compound which is inorganic and a polymer which is organic, there are concerns for film formation defects, degradation of storage stability, degradation of dry etching resistance, etc. caused by compatibility failure.
The present invention has been made in view of the above-described circumstances. An object of the present invention is to provide: a compound for forming a metal-containing film having better dry etching resistance than conventional organic underlayer film materials and also having high filling and planarizing properties; a composition for forming a metal-containing film containing the compound; and a patterning process in which the composition is used.
To achieve the object, the present invention provides a compound for forming a metal-containing film, wherein the compound is represented by the following general formula (M),
wherein R1 and R2 each independently represent an organic group or a halogen atom; and W represents a divalent organic group represented by the following general formula (W-1) or (W-2),
wherein “I” represents an integer of 2 or 3; R3 and R4 each independently represent a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, a hydrogen atom, or a halogen atom, or the R3 and the R4 on a single carbon atom form a carbonyl group together with the carbon atom bonded thereto, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group, the R3 and the R4 on a single carbon atom optionally being bonded to each other to form a cyclic structure, and the R3 and the R4 on adjacent carbon atoms optionally being bonded to each other to form a cyclic structure; each R5 independently represents a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, or a halogen atom, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group; “n” represents an integer of 0 or 1; “m” represents an integer of 0 to 6; and represents an attachment point to —OSn.
Here, a heteroalkyl group indicates an alkyl group that further contains one or more (e.g. one, two, three, or four) heteroatoms (e.g. oxygen, sulfur, nitrogen, boron, silicon, or phosphorus) in the main chain of the alkyl group. A heteroatom may be interposed between adjacent carbon atoms within the parent carbon chain of the heteroatom or may be interposed between a carbon atom and the parent molecule thereof (i.e. in the attachment point). However, substituted or unsubstituted alkoxy groups having 1 to 20 carbon atoms and substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, the groups containing an ester group or an amide group, are excluded.
The compound for forming a metal-containing film, which can be bonded to Sn by two hydroxy groups contained in a catechol, diol, or α-hydroxycarboxylic acid as described, requires bond cleavage at two points when an organic ligand sublimates, and therefore, is a tin-containing compound having better heat resistance than an ordinary compound having a monovalent ligand. Thus, it is possible to suppress volume shrinkage, which induces the degradation of filling property. In addition, since the two organic groups represented by R1 and R2 are contained, thermal flowability can also be imparted. Therefore, it is possible to form a metal-containing film excellent in film-formability and filling and planarizing properties even after high-temperature baking.
The R1 in the general formula (M) is preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aliphatic unsaturated organic group having 2 to 20 carbon atoms and having one or more double bonds or triple bonds, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms.
When the R1 is as described above, radicals are generated by the homolytic cleavage of tin-carbon bonds at the time of baking, so that the radicals cause a crosslinking reaction, and excellent thermosetting property can be achieved. Therefore, it is possible to form a metal-containing film excellent in film-formability and filling and planarizing properties even after high-temperature baking.
In the general formula (M), the R2 preferably represents —OC(═O)R2′, R2′ representing a monovalent organic group.
When the R2 in the general formula (M) is —OC(═O)R2′, the symmetry in the structure of the compound is broken, and therefore, it is possible to form a metal-containing film excellent in solvent solubility. In addition, in —OC(═O)R2′, the R2′ can be freely changed, so that by incorporating a bulky structure, further improvement in solubility and thermal flowability can be expected. Furthermore, it is also possible to provide a crosslinking structure, and therefore, sublimation products can be suppressed, and the suppression of volume shrinkage, which induces degradation in filling property, can also be expected. In this manner, it is possible to form a metal-containing film excellent in film-formability and filling and planarizing properties even after high-temperature baking.
In the present invention, the R2′ preferably represents one of the following general formulae (A-1) to (A-4), the following general formula (2), or the following general formula (3),
wherein YA1 and YA2 are each identical to or different from each other and represent a substituted or unsubstituted saturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms; RA represents a hydrogen atom, a substituted or unsubstituted saturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms; RA1 represents an organic group whose protecting group is to be removed by an action of an acid, heat, or both to generate one or more hydroxy groups or carboxyl groups, RA1 being represented by one of the following general formulae (1); and “*” represents an attachment point to the carbonyl group,
wherein RA2 represents an organic group whose protecting group is to be removed by an action of an acid, heat, or both; and “*” represents an attachment point to YA1 or YA2,
wherein X represents a divalent organic group having 1 to 31 carbon atoms; B represents the following general formula (B); and “*” represents an attachment point to the carbonyl group,
B=*-YB-RB (B)
wherein YB represents a substituted or unsubstituted saturated divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted divalent arylalkyl group having 7 to 31 carbon atoms, YB optionally being bonded to an adjacent group via an oxygen atom or an NH group; RB represents a hydroxy group or a structure represented by one of the following general formulae (B-1) to (B-3); and “*” represents an attachment point to the carbonyl group,
wherein RB1 represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms; “q” represents 0 or 1; and “*” represents an attachment point to YB,
wherein X represents a divalent organic group having 1 to 31 carbon atoms; C represents a group represented by one of the following general formulae (C-1) to (C-4); and “*” represents an attachment point to the carbonyl group,
wherein RC1s each independently represent a hydrogen atom or a methyl group and are identical to or different from each other in a single formula; RC2 represents a hydrogen atom, a substituted or unsubstituted, saturated or unsaturated monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms; and “*” represents an attachment point to the carbonyl group.
When the R2′ has a structure represented by one of the general formulae (A-1) to (A-4), a bulky heat/acid-labile group is contained in the structure, and therefore, thermal flowability can be enhanced. Furthermore, when the compound is contained in a composition for forming a metal-containing film, the heat/acid-labile groups are eliminated during baking, so that hydroxy groups and carboxyl groups are generated. The OH or the α-hydrogen of a carboxylic acid generated in this manner react easily with radicals that are generated by the cleavage of tin-carbon bonds when baking is performed, and therefore, a crosslinking reaction occurs, providing excellent thermosetting property. Thus, it is possible to suppress volume shrinkage, which causes the degradation of flatness and filling property, and it is possible to form a metal-containing film excellent in film-formability and planarizing and filling properties even after high-temperature baking.
Meanwhile, when the R2′ has the structure represented by the general formula (2), a hydroxy group or a crosslinking group of one of the structures represented by the general formulae (B-1) to (B-3) is included at an end, and therefore, when the compound is contained in a composition for forming a metal-containing film, the compound reacts easily with radicals that are generated by the cleavage of tin-carbon bonds when baking is performed, and therefore, a crosslinking reaction occurs, and furthermore, the crosslinking groups themselves also undergo a crosslinking reaction, providing excellent thermosetting property. Thus, it is possible to suppress volume shrinkage, which causes the degradation of flatness and filling property, and it is possible to form a metal-containing film excellent in film-formability and planarizing and filling properties even after high-temperature baking.
Meanwhile, when the R2′ has the structure represented by the general formula (3), one of the structures represented by (C-1) to (C-4) is contained, and therefore, the crosslinking-group density is high, providing excellent thermosetting property. Therefore, when the compound is contained in a composition for forming a metal-containing film, volume shrinkage at the time of baking is low, and it is possible to form a metal-containing film excellent in film-formability and planarizing and filling properties even after high-temperature baking.
In the present invention, it is preferable that the YA1 in the general formulae (A-1) to (A-4), the X in the general formula (2), or the X in the general formula (3) be a substituted or unsubstituted unsaturated divalent hydrocarbon group having 2 to 20 carbon atoms.
When the YA1 in the general formulae (A-1) to (A-4), the X in the general formula (2), or the X in the general formula (3) is a substituted or unsubstituted unsaturated divalent hydrocarbon group having 2 to 20 carbon atoms, the thermosetting property of the compound for forming a metal-containing film can be further improved.
The present invention can provide a compound for forming a metal-containing film, where the YA1 in the general formulae (A-1) to (A-4), the X in the general formula (2), or the X in the general formula (3) represents one of the following general formulae (4),
wherein Ra, Rb, and Rc each represent a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, Ra and Rb optionally being bonded to each other to form a cyclic substituent; and “*1” and “*2” each represent an attachment point to the carbonyl group, substitution positions of “*1” and “*2” optionally being reversed.
A compound for forming a metal-containing film having such a structure can achieve both high thermal flowability and high thermosetting property, and when the compound is contained in a composition for forming a metal-containing film, it is possible to form a metal-containing film that exhibits better planarizing and filling properties.
The compound for forming a metal-containing film preferably satisfies 1.00 s Mw/Mn s 1.50, where Mw is a weight-average molecular weight and Mn is a number-average molecular weight measured by gel permeation chromatography in terms of polystyrene.
A compound for forming a metal-containing film having a dispersity of such a range has even better thermal flowability, and therefore, when the compound is contained in a composition for forming a metal-containing film, not only is it possible to fill favorably a fine structure formed on a substrate, it is also possible to form a resist underlayer film that is flat across the entire substrate.
In addition, the present invention provides a composition for forming a metal-containing film, the composition functioning as a resist underlayer film material used in manufacturing a semiconductor, the composition comprising: (a) the above-described compound for forming a metal-containing film; and (b) an organic solvent.
Such a composition for forming a metal-containing film contains an organotin compound excellent in solvent solubility, heat resistance, and thermal flowability, and therefore, makes it possible to form a metal-containing film that has better dry etching resistance than conventional organic underlayer film materials and also has high filling and planarizing properties.
The inventive composition is usable as a resist underlayer film used in a multilayer resist method, and the composition can further comprise one or more of (c) a crosslinking agent, (d) a surfactant, (e) a flowability accelerator, and (f) an acid generator.
Such a composition is provided with favorable properties by the above-mentioned components being contained with the compound for forming a metal-containing film, and has both more suitable high filling property and more suitable high planarizing property.
Furthermore, in the present invention, the organic solvent (b) is preferably a mixture of one or more kinds of organic solvent having a boiling point of lower than 180° C. and one or more kinds of organic solvent having a boiling point of 180° C. or higher.
When the above-described compound for forming a metal-containing film is provided with thermal flowability by the high-boiling-point solvent being contained, such a composition for forming a metal-containing film is provided with both higher filling property and higher planarizing property. Note that, in the present description, the boiling point is the value at a pressure of 1 atmosphere (1013 hPa).
In addition, the present invention provides a patterning process for forming a pattern in a substrate to be processed, comprising the steps of:
The patterning process by way of the two-layer resist process makes it possible to form fine patterns on the body to be processed (substrate to be processed).
The present invention also provides a patterning process for forming a pattern in a substrate to be processed, comprising the steps of:
The patterning process by way of the three-layer resist process makes it possible to form fine patterns on the body to be processed with high accuracy.
The present invention also provides a patterning process for forming a pattern in a substrate to be processed, comprising the steps of:
The patterning process by way of the four-layer resist process makes it possible to form fine patterns on the body to be processed with high accuracy.
In this case, the inorganic hard mask is preferably formed by a CVD method or an ALD method.
When the inorganic hard mask is formed by a CVD method or an ALD method, a fine pattern can be formed on a body to be processed with higher accuracy.
The present invention also provides a patterning process for forming a pattern in a substrate to be processed, comprising the steps of:
The patterning process by way of the multilayer resist process makes it possible to form fine patterns on the body to be processed with high accuracy.
The present invention also provides a patterning process for forming a pattern in a substrate to be processed, comprising the steps of:
The patterning process by way of the reverse process makes it possible to form fine patterns on the body to be processed with even higher accuracy.
In this case, too, the inorganic hard mask is preferably formed by a CVD method or an ALD method.
When the inorganic hard mask is formed by a CVD method or an ALD method, a fine pattern can be formed on a body to be processed with higher accuracy.
As described above, in the inventive compound for forming a metal-containing film, as shown in the general formula (M), a catechol, diol, or α-hydroxycarboxylic acid is bonded via the two hydroxy groups thereof to Sn, and therefore, the compound for forming a metal-containing film is excellent in heat resistance. In addition, since the compound for forming a metal-containing film further contains two organic groups as well, the compound is excellent in thermal flowability, and by further modifying the structures of the organic groups, the performance of the compound can be tuned. When the compound is contained in a composition for forming a metal-containing film, it is possible to suppress volume shrinkage, which induces the degradation of filling property, and therefore, it is possible to form a metal-containing film, such as a resist underlayer film, that is excellent in film-formability and planarizing and filling properties even after high-temperature baking.
In particular, in a fine patterning process using a multilayer resist method in a semiconductor device manufacturing process, filling is possible without causing defects such as voids and peeling even on a substrate to be processed having a portion that is difficult to fill and planarize, such as a dense portion of a fine pattern structure having a high aspect ratio exemplified by increasingly miniaturized DRAM. In addition, the inventive compound has better dry etching resistance than conventional coating-type organic resist underlayer film materials, and therefore, a fine pattern can be formed on a body to be processed with even higher precision compared with an organic resist underlayer film.
A composition for forming a metal-containing film containing the inventive compound for forming a metal-containing film contains a tin atom, which has high EUV light absorbance, and therefore, has a sensitizing effect caused by secondary electrons generated from the tin atom during exposure. Furthermore, tin atoms have a great atomic weight, and therefore, have a high effect of suppressing the diffusion of acid from an upper layer resist to a resist underlayer film, and have a characteristic that higher sensitivity can be achieved while sustaining the LWR performance that the resist upper layer film originally has.
As stated above, there have been demands for the development of: a composition for forming a metal-containing film, excellent in filling property and planarization property, used for forming a resist underlayer film that makes it possible to transfer a resist pattern to a substrate to be processed with higher precision in a fine patterning process according to a multilayer resist method; and a compound for forming a metal-containing film useful for the composition.
The present inventors have focused on organotin compounds, which are expected to play an active role in the EUV-exposure generation, and studied earnestly. As stated above, tin atoms, which greatly absorb light, have a sensitizing effect due to secondary electrons generated from the atoms during exposure, and have a characteristic that higher sensitivity can be achieved while maintaining the LWR performance that a resist upper layer film originally has. On the other hand, organotin compounds, which are considered as resist upper layer films, have poor heat resistance, and undergo rapid volume shrinkage during baking. Therefore, it is difficult to fill and planarize the steps of a substrate to be processed after high-temperature baking. The present inventors have considered that the bonds of a diol- or catechol-based compound, which can be bonded to a tin atom by a valency of 2 per molecule, are not easily cleaved at the time of baking, and therefore, heat resistance can be enhanced. The present inventors have also considered that since the compound contains two organic groups that are not associated with the bonds with the diol or catechol, a compound for forming a metal-containing film excellent in solubility and thermal flowability can be achieved, and furthermore, by appropriately adjusting the structures of the organic groups, properties can be tuned.
The present inventors have studied earnestly further, and found out that a compound for forming a metal-containing film represented by the general formula (M) can suppress sudden volume shrinkage during baking and also has excellent thermal flowability, and therefore, has excellent film-formability, filling property, and planarizing property. Thus, the present invention has been completed.
That is, the present invention is a compound for forming a metal-containing film, wherein the compound is represented by the following general formula (M),
wherein R1 and R2 each independently represent an organic group or a halogen atom; and W represents a divalent organic group represented by the following general formula (W-1) or (W-2),
wherein “I” represents an integer of 2 or 3; R3 and R4 each independently represent a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, a hydrogen atom, or a halogen atom, or the R3 and the R4 on a single carbon atom form a carbonyl group together with the carbon atom bonded thereto, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group, the R3 and the R4 on a single carbon atom optionally being bonded to each other to form a cyclic structure, and the R3 and the R4 on adjacent carbon atoms optionally being bonded to each other to form a cyclic structure; each R5 independently represents a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, or a halogen atom, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group; “n” represents an integer of 0 or 1; “m” represents an integer of 0 to 6; and represents an attachment point to —OSn.
Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto. The recitations of numerical ranges by endpoints include all numbers subsumed within that range.
The inventive compound for forming a metal-containing film is represented by the following general formula (M).
In the general formula (M), R1 and R2 each independently represent an organic group or a halogen atom; and W represents a divalent organic group represented by the following general formula (W-1) or (W-2).
In the general formula (W-1), “I” represents an integer of 2 or 3; and R3 and R4 each independently represent a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, a hydrogen atom, or a halogen atom, or the R3 and the R4 on a single carbon atom form a carbonyl group together with the carbon atom bonded thereto, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group, the R3 and the R4 on a single carbon atom optionally being bonded to each other to form a cyclic structure, and the R3 and the R4 on adjacent carbon atoms optionally being bonded to each other to form a cyclic structure. In the general formula (W-2), each R5 independently represents a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, or a halogen atom, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group; “n” represents an integer of 0 or 1; “m” represents an integer of 0 to 6; and “*” represents an attachment point to —OSn.
In the general formula (M), R1 and R2 each independently represent an organic group or a halogen group, and from the viewpoints of the availability of raw materials and synthesis, preferably an alkyl group, an ester group, an alkoxy group, or a chlorine atom, and from the viewpoint of solvent solubility, R1 and R2 preferably have different structures in a single compound. Furthermore, considering thermal flowability, R1 and R2 are preferably a combination of an alkyl group and an ester group.
In the general formula (W-1), R3 and R4 each independently represent a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, a hydrogen atom, or a halogen atom, or the R3 and the R4 on a single carbon atom form a carbonyl group together with the carbon atom bonded thereto, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group. The R3 and the R4 on a single carbon atom are optionally bonded to each other to form a cyclic structure, and the R3 and the R4 on adjacent carbon atoms are optionally bonded to each other to form a cyclic structure, and from the viewpoints of crosslinking property and heat resistance, R3 and R4 are preferably each an unsaturated hydrocarbon group or an organic group having a hydroxy group.
Specific examples where the general formulae R3 and R4 are each independent include the following, but are not limited thereto. Incidentally, in the following formulae, “*” represents an attachment point.
Specific examples of the general formula (W-1) where the general formulae R3 and R4 are bonded to each other to form a cyclic structure include the following, but are not limited thereto. Incidentally, in the following formulae, “*” represents an attachment point to the oxygen atom.
The R3 and the R4 on a single carbon atom optionally form a carbonyl group together with the carbon atom bonded thereto, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group.
When the R3 and R4 the on a single carbon atom are both hydroxy groups, a gem-diol group is formed, and when the group is dehydrated, a carbonyl group is formed together with the carbon atom bonded to R3 and R4. That is, the divalent organic group represented by the formula (W-1) may be a divalent organic group containing such a carbonyl group.
When the R3 and the R4 on a single carbon atom form a carbonyl group together with the carbon atom bonded thereto, an α-hydroxycarboxylic acid, where the “I” in the general formula (W-1) is 2, is preferably formed. Examples of the α-hydroxycarboxylic acid include substituted compounds of hydroxyacetic acid (glycolic acid), such as lactic acid, 2-hydroxybutyric acid, tartaric acid, malic acid, citric acid, isocitric acid, mandelic acid, and benzilic acid. In this case, the α position of the hydroxyacetic acid can be substituted with a hydrocarbon group having 1 to 30 carbon atoms, optionally including an aromatic ring, such as a benzene ring, and the aromatic ring may be further substituted with a hydroxy group.
The “I” in the general formula (W-1) represents an integer of 2 or 3, and from the viewpoints of the stability of the compound and the availability of raw materials, preferably 2.
The general formula (W-1) preferably has a structure shown below from the viewpoints of the availability of raw materials, heat resistance, and thermal flowability. Incidentally, in the following formulae, represents an attachment point to the oxygen atom.
In the formula (W-2), each R5 independently represents a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, or a halogen atom, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group. From the viewpoint of heat resistance, R5 is preferably an organic group containing an unsaturated hydrocarbon or an organic group having a hydroxy group.
“n” represents an integer of 0 or 1 and “m” represents an integer of 0 to 6, and from the viewpoints of the availability of raw materials and further increasing the tin content, “n” is preferably 0, and “m” is preferably 1. “*” represents an attachment point to —OSn.
Specific examples of the R5 in the general formula (W-2) include the following, but are not limited thereto. Incidentally, in the following formulae, “*” represents an attachment point to the aromatic ring.
The general formula (W-2) preferably has a structure shown below from the viewpoints of the availability of raw materials, heat resistance, and thermal flowability.
In the general formula (M), R1 is preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 20 carbon atoms, a substituted or unsubstituted aliphatic unsaturated organic group having 2 to 20 carbon atoms and having one or more double bonds or triple bonds, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms. From the viewpoint of suppressing sublimation products, R1 is more preferably an unsubstituted alkyl group having 1 to 20 carbon atoms, and from the viewpoint of the availability of raw materials, particularly preferably an n-butyl group.
Such a compound for forming a metal-containing film contains an Sn-alkyl bond in the compound, and therefore, the bond is cleaved at the time of baking, so that radicals are generated. Therefore, a crosslinking reaction originating from the radicals takes place, allowing excellent thermosetting property. Accordingly, it is possible to form a metal-containing film, such as a resist underlayer film material excellent in film-formability, filling property, and planarizing property even after baking at a high temperature.
Furthermore, the R2 in the general formula (M) is preferably —OC(═O)R2′, from the viewpoint of solvent solubility.
Such a compound for forming a metal-containing film is asymmetrical, and therefore, is excellent in solvent solubility, and is also excellent in thermal flowability, so that it is possible to provide a resist underlayer film excellent in planarizing property. In addition, —OC(═O)R2′ makes it possible to change the R2′ freely, so that it is possible to increase the molecular weight or provide a crosslinking structure, and therefore, sublimation products can be suppressed. Therefore, volume shrinkage, which causes the degradation of filling property, can be suppressed, and it is possible to form a metal-containing film excellent in film-formability and filling and planarizing properties even after high-temperature baking.
In the R2, the R2′ preferably represents one of the following general formulae (A-1) to (A-4), the following general formula (2), or the following general formula (3).
In the general formulae (A-1) to (A-4), YA1 and YA2 are each identical to or different from each other and represent a substituted or unsubstituted saturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms; RA represents a hydrogen atom, a substituted or unsubstituted saturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms; RA1 represents an organic group whose protecting group is to be removed by an action of an acid, heat, or both to generate one or more hydroxy groups or carboxyl groups, RA1 being represented by one of the following general formulae (1); and represents an attachment point to the carbonyl group.
In the general formulae (1), RA2 represents an organic group whose protecting group is to be removed by an action of an acid, heat, or both; and “*” represents an attachment point to YA1 or YA2.
In the general formulae (A-1) to (A-4), YA1 and YA2 are each identical to or different from each other and represent a substituted or unsubstituted saturated divalent hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent hydrocarbon group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms. RA represents a hydrogen atom, a substituted or unsubstituted saturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms. RA1 represents an organic group whose protecting group is to be removed by an action of an acid, heat, or both to generate one or more hydroxy groups or carboxyl groups, RA1 being represented by one of the general formulae (1).
Examples of favorable structures of the YA2 in the general formulae (A-2) to (A-4) include the following structures, but are not limited thereto. In the following formulae, “*a” represents an attachment point to RA1, and “*b” represents the other attachment point.
The RA in the general formula (A-3) represents a hydrogen atom, a substituted or unsubstituted saturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms, and from the viewpoints of suppressing sublimation products and increasing the Sn content, preferably a hydrogen atom.
The RA2 in the general formula (1) represents an organic group whose heat/acid-labile group is to be removed by an action of an acid, heat, or both, preferably a tertiary hydrocarbyl group, an acyl group, or a group that forms an acetal structure together with the adjacent oxygen atom, particularly preferably a tertiary hydrocarbyl group.
As the tertiary hydrocarbyl group, those having 4 to 20 carbon atoms are preferable, and from the viewpoints of suppressing sublimation products due to thermal decomposition products and the ease of acquiring raw materials, a tert-butyl group is particularly preferable. Specific examples include those shown below, but are not limited thereto. Incidentally, in the following formulae, “*” represents an attachment point to the oxygen atom.
The acyl group is not particularly limited, but examples include formyl, acetyl, propionyl, butyryl, acryloyl, methacryloyl, malonyl, benzoyl, and naphthoyl groups.
The group forming the acetal structure is not particularly limited as long as it is an organic group whose labile group is eliminated or cleaved by the action of an acid, heat, or both. Specific examples of the group forming the acetal structure include those shown below, but are not limited thereto. Incidentally, in the following formulae, “*” represents an attachment point to the oxygen atom.
Such a compound for forming a metal-containing film is excellent in solvent solubility and thermal flowability. Furthermore, since a heat/acid-labile group is contained in the RA1, when the compound is contained in a composition for forming a metal-containing film, the groups are removed during baking, so that the tin content increases. Thus, the compound for forming a metal-containing film is provided with excellent dry etching resistance. Furthermore, the hydroxy groups or carboxyl groups generated by the removal easily react with the radicals that are generated by the cleavage of the tin-carbon bonds at the time of baking because of the presence of terminal OH or α-hydrogen, so that a crosslinking reaction occurs, and excellent thermosetting property can be provided. Therefore, volume shrinkage can be suppressed, and it is possible to form a metal-containing film that is excellent in film-formability and planarizing and filling properties even after high-temperature baking.
In a metal-containing film formed by using an organotin compound, the organic groups bonded to the Sn atoms via a C atom generate radicals while being dissociated during baking, and the generated radicals form —Sn—O—Sn— bonds, initiating a condensation polymerization reaction. Thus, the curing of the metal-containing film progresses. On the other hand, since organic groups are removed at the same time as the reaction, great film shrinkage occurs during baking. However, the compound has a heat/acid-labile group on an end, and the heat/acid-labile group is removed during baking to generate a hydroxy group or a carboxyl group. The OH or α-hydrogen on the end of the hydroxy group or carboxyl group easily react with the radicals, and a crosslinking reaction occurs as in the following reaction formula. Since at least one of such an organic group is contained, it is possible to prevent the whole of the organic group from undergoing thermal decomposition and sublimation, and excellent thermal flowability is provided. Therefore, it is possible to form a metal-containing film excellent in filling property.
In the general formula (2), X represents a divalent organic group having 1 to 31 carbon atoms; B represents the following general formula (B); and “*” represents an attachment point to the carbonyl group.
B=*-YB-RB (B)
In the general formula (B), YB represents a substituted or unsubstituted saturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent organic group having 2 to 20 carbon atoms (preferably a divalent aliphatic hydrocarbon group), a substituted or unsubstituted divalent aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted divalent arylalkyl group having 7 to 31 carbon atoms, YB optionally being bonded to an adjacent group via an oxygen atom or an NH group. RB represents a hydroxy group or a structure represented by one of the following general formulae (B-1) to (B-3). The YB may further have a hydroxy group in addition to the RB. “*” represents an attachment point to the carbonyl group.
In the general formulae (B-1) to (B-3), RB1 represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms; “q” represents 0 or 1; and “*” represents an attachment point to YB.
In the general formula (2), X represents a divalent organic group having 1 to 31 carbon atoms; B represents the following general formula (B); and “*” represents an attachment point to the carbonyl group. In the general formula (B), it is preferable that YB represent a saturated divalent organic group having 1 to 20 carbon atoms, an unsaturated divalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted divalent arylalkyl group having 7 to 31 carbon atoms; and RB represent a hydroxy group or one of the structures represented by the following general formulae (B-1) to (B-3). In the general formulae (B-1) to (B-3), RB1 represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and from the viewpoint of suppressing sublimation products, preferably a hydrogen atom.
Examples of preferable structures of the general formula (B) include the following structures, but are not limited thereto. Incidentally, in the following formulae, “*” represents an attachment point to the carbonyl group. The following examples also represent possible structural isomers.
Such a compound for forming a metal-containing film is excellent in solvent solubility and thermal flowability. Furthermore, since a hydroxy group or an unsaturated bond is contained in the RB, when the compound is contained in a composition for forming a metal-containing film, the hydroxy group or unsaturated bond causes a crosslinking reaction during baking, so that excellent thermosetting property is provided, and furthermore, by the hydroxy group or unsaturated bond also reacting with the radicals generated by the cleavage of the tin-carbon bonds, the crosslinking reaction is promoted, and excellent thermosetting property is provided. Thus, volume shrinkage can be suppressed, and it is possible to form a metal-containing film excellent in film-formability and planarizing and filling properties even after high-temperature baking.
In the general formula (3), X represents a divalent organic group having 1 to 31 carbon atoms; C represents one of the following general formulae (C-1) to (C-4); and “*” represents an attachment point to the carbonyl group.
In the general formulae (C-1) and (C-3), RC1s each represent a hydrogen atom or a methyl group and are identical to or different from each other in a single formula. In (C-3) and (C-4), RC2 represents a hydrogen atom, a substituted or unsubstituted, saturated or unsaturated monovalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms. “*” represents an attachment point to the carbonyl group.
In the general formula (3), X represents a divalent organic group having 1 to 31 carbon atoms, and specific examples include substituted or unsubstituted saturated divalent hydrocarbon groups having 1 to 20 carbon atoms, substituted or unsubstituted unsaturated divalent hydrocarbon groups having 2 to 20 carbon atoms, substituted or unsubstituted aryl groups having 6 to 30 carbon atoms, substituted or unsubstituted arylalkyl groups having 7 to 31 carbon atoms, etc. C represents one of the general formulae (C-1) to (C-4). In (C-1) and (C-3), RC1 is preferably a methyl group from the viewpoint of thermal flowability, and is preferably a hydrogen atom from the viewpoint of curability. In addition, the RC2 in (C-3) and (C-4) is preferably one of the above-described structures other than a hydrogen atom from the viewpoint of thermal flowability.
Examples of favorable structures of the RC2 in the general formulae (C-1) to (C-4) include the following structures, but are not limited thereto. Incidentally, in the following formulae, “*” represents an attachment point to the nitrogen atom.
A compound for forming a metal-containing film having such a structure contains an organic group represented by the general formula (3), and therefore, is excellent in solvent solubility and heat resistance, and furthermore, contains one of the structures represented by the general formulae (C-1) to (C-4) on an end, and therefore, has a high density of crosslinking groups, so that rapid volume shrinkage during baking can be reduced. Moreover, the compound also has excellent thermal flowability, and therefore, it is possible to form a metal-containing film excellent in filling and planarizing properties.
Specific examples of the structure of the YA1 in the general formulae (A-1) to (A-4), the X in the general formula (2), or the X in the general formula (3) include the following structures, but are not limited thereto. Incidentally, in the following formulae, “*” represents an attachment point to the carbon atom of the carbonyl group or the “*” in the formulae (A-1) to (A-4), (2), or (3).
In the compound for forming a metal-containing film, the YA1 in the general formulae (A-1) to (A-4), the X in the general formula (2), or the X in the general formula (3) is preferably a substituted or unsubstituted unsaturated divalent hydrocarbon group having 2 to 20 carbon atoms.
When the YA1 in the general formulae (A-1) to (A-4), the X in the general formula (2), or the X in the general formula (3) is a substituted or unsubstituted unsaturated divalent hydrocarbon group having 2 to 20 carbon atoms, the thermosetting property of the compound for forming a metal-containing film can be further improved.
Furthermore, it is possible to provide a compound for forming a metal-containing film in which the YA1 in the general formulae (A-1) to (A-4), the X in the general formula (2), or the X in the general formula (3) represents one of the following general formulae (4).
In the general formulae (4), Ra, Rb, and Rc each represent a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, Ra and Rb optionally being bonded to each other to form a cyclic substituent, and “*1” and “*2” each represent an attachment point to the carbonyl group, “*1” and “*2” optionally being reversed.
A carboxylic acid raw material containing one of the general formulae (4) can be synthesized by ring-opening an acid anhydride, and in this event, when an asymmetrical carboxylic anhydride is ring-opened, a mixture of two types is obtained, and therefore, the above-described bonding form is obtained. By such isomers being present, crystallinity can be suppressed, and improvement in planarizing property, achieved by improvement in solvent solubility and improvement in thermal flowability, can be expected.
In the general formulae (4), Ra, Rb, and Rc each represent a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, Ra and Rb optionally being bonded to each other to form a cyclic substituent. From the viewpoint of suppressing sublimation products, a hydrogen atom is particularly preferable.
The compound for forming a metal-containing film preferably satisfies 1.00 s Mw/Mn s 1.50, where Mw is a weight-average molecular weight and Mn is a number-average molecular weight measured by gel permeation chromatography in terms of polystyrene.
From the definition, Mw/Mn is 1.00 when the compound is a monomolecular compound. However, for reasons of separability in gel permeation chromatography, the measured value exceeds 1.00 in some cases. Generally, it is extremely difficult to bring Mw/Mn close to 1.00 in a polymer having a repeating unit unless a special polymerization method is used, there is a molecular weight distribution, and Mw/Mn becomes a value greater than 1. In the present invention, 1.00 s Mw/Mn s 1.50 has been defined as an index indicating monomerism in order to distinguish between a monomolecular compound and a polymer.
A compound for forming a metal-containing film having a dispersity within such a range has even better thermal flowability, and therefore, when the compound is contained in a composition for forming a metal-containing film, it is possible to form a resist underlayer film that can not only fill well a fine structure formed on a substrate but can also achieve flatness across the entire substrate.
The method for obtaining the inventive compound for forming a metal-containing film may be performed by a known synthesis means, and is not particularly limited. For example, the compound can be prepared by methods disclosed in JPH5-123579A, JPS52-153913A, etc.
Specifically, the target compound can be obtained by: allowing a reaction (a ligand exchange reaction or the like) to take place between an Sn(IV) compound from which the target compound (tin compound) for forming a metal-containing film can be derived and a diol compound, such as catechol or α-hydroxycarboxylic acid, or a precursor thereof in an appropriate solvent, such as toluene; and after the completion of the reaction, removing the solvent, by-products, etc. under appropriate conditions, such as under reduced pressure. If necessary, an asymmetrical compound can be obtained by performing the above-described reaction with added carboxylic acid.
Furthermore, the present invention can provide a composition for forming a metal-containing film, the composition functioning as a resist underlayer film material used in manufacturing a semiconductor, the composition containing: (a) the compound for forming a metal-containing film; and (b) an organic solvent.
Such a composition for forming a metal-containing film contains an organotin compound having excellent heat resistance and thermal flowability, and therefore, makes it possible to form a metal-containing film, such as a resist underlayer film material, having better dry etching resistance than conventional organic underlayer film materials and also having both high filling property and high planarizing property.
In the following, the components contained in the inventive composition for forming a metal-containing film other than the compound (a) for forming a metal-containing film will be described.
The organic solvent (b) usable in the inventive composition for forming a metal-containing film is not particularly limited as long as the solvent can dissolve or disperse the compound (a) for forming a metal-containing film, (c) a crosslinking agent, (d) a surfactant, (e) a flowability accelerator, (f) an acid generator, other additives, etc.
Specifically, an organic solvent disclosed in paragraphs [0091] and [0092] in JP2007-199653A may be contained. Further specifically, it is preferable to use propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, 2-heptanone, cyclopentanone, cyclohexanone, γ-butyrolactone, or a mixture containing one or more of these solvents. (High-Boiling-Point Solvent)
In the inventive composition for forming a metal-containing film (composition for forming a resist underlayer film), the organic solvent (b) may be a mixture of one or more kinds of organic solvent having a boiling point (the value at 1 atmosphere (1013 hPa)) of lower than 180° C. and one or more kinds of organic solvent having a boiling point of 180° C. or higher (a high-boiling-point solvent).
The high-boiling-point solvent is not particularly limited to hydrocarbons, alcohols, ketones, esters, ethers, or chlorine-based solvents as long as the solvent is capable of dissolving or dispersing the components of the inventive composition for forming a metal-containing film. Specific examples include 1-octanol, 2-ethylhexanol, 1-nonanol, 1-decanol, 1-undecanol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, glycerin, n-nonyl acetate, monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol monophenyl ether, diethylene glycol monobenzyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol-n-butyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether, tripropylene glycol dimethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono-n-propyl ether, tripropylene glycol mono-n-butyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, triacetin, propylene glycol diacetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1,6-hexanediol diacetate, triethylene glycol diacetate, γ-butyrolactone, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, dihexyl malonate, diethyl succinate, dipropyl succinate, dibutyl succinate, dihexyl succinate, dimethyl adipate, diethyl adipate, dibutyl adipate, and the like. One of the solvents may be used or a mixture of two or more kinds may be used.
The high-boiling-point solvent may be selected suitably from the solvents above, for example, depending on the temperature at which the inventive composition for forming a metal-containing film is heat-treated, etc. The boiling point of the high-boiling-point solvent is preferably 180° C. to 300° C., further preferably 200° C. to 300° C. It is considered that when the boiling point is as described, sufficient thermal flowability can be achieved at the time of film formation, since there is no risk of excessive evaporation rate at the baking (heating). Thus, it is possible to form a resist underlayer film excellent in filling and planarizing properties. Moreover, a solvent having such a boiling point does not remain in the film without evaporating even after the baking. Therefore, there is no risk of the solvent adversely affecting the physical properties, such as etching resistance, of the film.
The organic solvent is preferably contained in an amount of 200 to 10,000 parts by mass, more preferably 250 to 5,000 parts by mass based on 100 parts by mass of the compound (a) for forming a metal-containing film.
Furthermore, when the high-boiling-point solvent is used, the contained amount is preferably 1 to 30 parts by mass per 100 parts by mass of the organic solvent having a boiling point lower than 180° C. When the contained amount is as described, sufficient thermal flowability can be imparted at the time of baking, so that the solvent does not remain in the film and cause degradation in the physical properties, such as etching resistance, of the film. Therefore, such an amount is preferable.
The above-described composition is a composition for forming a metal-containing film that is usable as a resist underlayer film used in multilayer resist methods, and can further contain one or more of (c) a crosslinking agent, (d) a surfactant, (e) a flowability accelerator, and (f) an acid generator.
In the following, the components contained in the inventive composition for forming a metal-containing film (composition for forming a resist underlayer film) other than the compound (a) for forming a metal-containing film and the organic solvent (b) will be described.
To increase the denseness of the film and further inhibit intermixing with the resist upper layer film, the composition of the present invention for forming a resist underlayer film may also contain a crosslinking agent (c). The crosslinking agent is not particularly limited, and various known crosslinking agents can be widely used. Examples include melamine-based crosslinking agents, acrylate-based crosslinking agents, glycoluril-based crosslinking agents, benzoguanamine-based crosslinking agents, urea-based crosslinking agents, β-hydroxyalkylamide-based crosslinking agents, isocyanurate-based crosslinking agents, aziridine-based crosslinking agents, oxazoline-based crosslinking agents, phenol-based crosslinking agents (e.g. polynuclear phenol-based crosslinking agents as methylol- or alkoxymethyl-modified) epoxy-based crosslinking agents, and oxetane-based crosslinking agents. The crosslinking agent (c) is preferably contained in an amount of 5 to 50 parts by mass, more preferably 10 to 40 parts by mass relative to 100 parts by mass of the compound (a) for forming a metal-containing film.
Specific examples of the melamine-based crosslinking agents include hexamethoxymethylated melamine, hexabutoxymethylated melamine, alkoxy- and/or hydroxy-substituted derivatives thereof, and partial self-condensates thereof.
Specific examples of the acrylate-based crosslinking agents include dipentaerythritol hexaacrylate.
Specific examples of the glycoluril-based crosslinking agents include tetramethoxymethylated glycoluril, tetrabutoxymethylated glycoluril, alkoxy- and/or hydroxy-substituted derivatives thereof, and partial self-condensates thereof.
Specific examples of the benzoguanamine-based crosslinking agents include tetramethoxymethylated benzoguanamine, tetrabutoxymethylated benzoguanamine, alkoxy- and/or hydroxy-substituted derivatives thereof, and partial self-condensates thereof.
Specific examples of the urea-based crosslinking agents include dimethoxymethylated dimethoxyethyleneurea, alkoxy- and/or hydroxy-substituted derivatives thereof, and partial self-condensates thereof.
Specific examples of the β-hydroxyalkylamide-based crosslinking agent include N,N,N′,N′-tetra(2-hydroxyethyl)adipic acid amide.
Specific examples of the isocyanurate-based crosslinking agents include triglycidyl isocyanurate and triallyl isocyanurate.
Specific examples of the aziridine-based crosslinking agents include 4,4′-bis(ethyleneiminocarbonylamino)diphenylmethane and 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate].
Specific examples of the oxazoline-based crosslinking agents include 2,2′-isopropylidene bis(4-benzyl-2-oxazoline), 2,2′-isopropylidene bis(4-phenyl-2-oxazoline), 2,2′-methylene bis-4,5-diphenyl-2-oxazoline, 2,2′-methylene bis-4-phenyl-2-oxazoline, 2,2′-methylene bis-4-tert-butyl-2-oxazoline, 2,2′-bis(2-oxazoline), 1,3-phenylene bis(2-oxazoline), 1,4-phenylene bis(2-oxazoline), and a 2-isopropenyloxazoline copolymer.
Specific examples of the polynuclear phenol-based crosslinking agents include compounds represented by the following general formula (XL-1).
In the formula, S represents a single bond or an s-valent hydrocarbon group having 1 to 20 carbon atoms. R6 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. “s” represents an integer of 1 to 5.
S represents a single bond or a hydrocarbon group having a valency of “s” and having 1 to 20 carbon atoms. “s” represents an integer of 1 to 5, more preferably 2 or 3. Specific examples of S include groups obtained by removing “s” hydrogen atoms from methane, ethane, propane, butane, isobutane, pentane, cyclopentane, hexane, cyclohexane, methylpentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, ethylbenzene, ethylisopropylbenzene, diisopropylbenzene, methylnaphthalene, ethylnaphthalene, and eicosane. R6 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. Specific examples of the alkyl group having 1 to 20 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, an isopentyl group, a hexyl group, an octyl group, an ethylhexyl group, a decyl group, and an eicosanyl group. Among these, a hydrogen atom or a methyl group is preferable.
Specific examples of the compounds represented by the general formula (XL-1) include the following compounds. Among these, triphenolmethane, triphenolethane, 1,1,1,-tris(4-hydroxyphenyl)ethane, and a hexamethoxymethylated derivative of tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene are preferable from the viewpoint of improving the curability and film thickness uniformity of the organic film. R6 is as defined above.
Examples of epoxy-based crosslinking agents and oxetane-based crosslinking agents include monomer types and polymer types, and specific examples of monomer types include the following, but are not limited thereto.
The above compounds can be purchased, but an epoxy-based crosslinking agent or an oxetane-based crosslinking agent can also be obtained by allowing a reaction between a hydroxy group and epibromohydrin, 3-bromomethyloxetane, or the like as in the following formula. In the following formula, R represents a substituted or unsubstituted saturated monovalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated monovalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms. In addition, it is also possible to leave some hydroxy groups and not allow all the hydroxy groups to react. In this event, the sum of the number of epoxy groups and the number of oxetane groups is preferably greater than the number of hydroxy groups, and more preferably, the sum of the epoxy groups and the oxetane groups is greater than twice the number of hydroxy groups. Furthermore, these compounds are preferably contained in an amount of 5 to 50 parts by mass, more preferably 10 to 40 parts by mass based on 100 parts by mass of the compound (a) for forming a metal-containing film.
Specific examples of compounds having a hydroxy group usable in the above-described reaction include the following, but are not limited thereto.
Meanwhile, specific examples of polymer types include polymers having a repeating unit represented by the following general formula (XL-2) and (XL-3) at a molar fraction of 20% or more. When the total of the molar fractions of the structural units represented by the general formulae (XL-2) and (XL-3) does not reach 100%, as the other structural units, it is possible to use a combination of any structural units derived from α,β-unsaturated carboxylic esters, such as other acrylates, other methacrylates, other acrylamides, other methacrylamides, crotonates, maleates, and itaconates; α,β-unsaturated carboxylic acids, such as methacrylic acid, acrylic acid, maleic acid, and itaconic acid; acrylonitrile; methacrylonitrile; α,β-unsaturated lactones, such as 5,5-dimethyl-3-methylene-2-oxotetrahydrofuran; cyclic olefins, such as norbornene derivatives and tetracyclo[4.4.0.12,5.17,10]dodecene derivatives; α,β-unsaturated carboxylic anhydrides, such as maleic anhydride and itaconic anhydride; allyl ethers; vinyl ethers; vinyl esters; and vinyl silanes. It is preferable that these polymers have a weight-average molecular weight of 1,000 to 20,000 and have a GPC dispersity of 2.0 or less. Furthermore, these compounds are preferably contained in an amount of 5 to 50 parts by mass, more preferably 10 to 40 parts by mass based on 100 parts by mass of the compound (a) for forming a metal-containing film.
In the formulae, R7 represents a hydrogen atom or a methyl group; R8 represents a hydrogen atom or a group selected from the following formulae (2-1) to (2-3); L1 represents a single bond or a divalent organic group containing —C(═O)O—, —C(═O)NH—, or —C(═O)NCH3—.
In the R8 in the general formulae (XL-2), the number of the groups of (2-1) to (2-3) is preferably greater than the number of hydrogen atoms, more preferably, the number of the groups of (2-1) to (2-3) is greater than twice the number of hydrogen atoms from the viewpoint of curability.
In the formula, R7 represents a hydrogen atom or a methyl group; and R9 represents a group selected from the following formulae (2-1) to (2-3).
In the formulae, a broken line represents an attachment point.
A surfactant (d) may be contained in the composition for forming a resist underlayer film of the present invention in order to improve coating property in spin-coating. Examples of the surfactant include those disclosed in paragraphs [0142] to [0147] of JP2009-269953A. When the surfactant is contained, the contained amount is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass per 100 parts by mass of the compound (a) for forming a metal-containing film.
Another compound or polymer may be further blended in the composition for forming a resist underlayer film of the present invention. The flowability accelerator is mixed with the inventive compound for forming a metal-containing film and serves to improve the film-formability by spin-coating and the filling property for a stepped substrate. Furthermore, as the flowability accelerator, a material having a high density of carbon atoms and high etching resistance is preferable.
Examples of such a material include novolak resins of phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethyl phenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2,6-dimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, 2-phenylphenol, 3-phenylphenol, 4-phenylphenol, 3,5-diphenylphenol, 2-naphthylphenol, 3-naphthylphenol, 4-naphthylphenol, 4-tritylphenol, resorcinol, 2-methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, catechol, 4-tert-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-tert-butyl-5-methylphenol, pyrogallol, thymol, isothymol, 4,4′-(9H-fluorene-9-ylidene)bisphenol, 2,2′-dimethyl-4,4′-(9H-fluorene-9-ylidene)bisphenol, 2,2′-diallyl-4,4′-(9H-fluorene-9-ylidene)bisphenol, 2,2′-difluoro-4,4′-(9H-fluorene-9-ylidene)bisphenol, 2,2′-diphenyl-4,4′-(9H-fluorene-9-ylidene)bisphenol, 2,2′-dimethoxy-4,4′-(9H-fluorene-9-ylidene)bisphenol, 2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-6,6′-diol, 3,3,3′,3′-tetramethyl-2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-6,6′-diol, 3,3,3′,3′,4,4′-hexamethyl-2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-6, 6′-diol, 2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-5,5′-diol, 5,5′-dimethyl-3,3,3′,3′-tetramethyl-2,3,2′,3′-tetrahydro-(1,1′)-spirobiindene-6,6′-diol, 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol, dihydroxynaphthalene such as 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene, methyl-3-hydroxynaphthalene-2-carboxylate, indene, hydroxyindene, benzofuran, hydroxyanthracene, acenaphthylene, biphenyl, bisphenol, trisphenol, dicyclopentadiene, tetrahydroindene, 4-vinylcyclohexene, norbornadiene, 5-vinylnorborna-2-ene, α-pinene, β-pinene, or limonene; polyhydroxystyrene, polystyrene, polyvinylnaphthalene, polyvinylanthracene, polyvinylcarbazole, polyindene, polyacenaphthylene, polynorbornene, polycyclodecene, polytetracyclododecene, polynortricyclene, poly(meth)acrylate, and copolymers thereof. In addition, the composition may contain a naphthol dicyclopentadiene copolymer disclosed in JP2004-205685A, a fluorene bisphenol novolak resin disclosed in JP2005-128509A, an acenaphthylene copolymer disclosed in JP2005-250434A, fullerene having a phenolic group disclosed in JP2006-227391A, a bisphenol compound and a novolak resin thereof disclosed in JP2006-293298A, a novolak resin of an adamantane phenol compound disclosed in JP2006-285095A, a bisnaphthol compound and a novolak resin thereof disclosed in JP2010-122656A, a fluorene compound disclosed in JP201 7-1 1 9671A, a fullerene resin compound disclosed in JP2008-158002A, and the like. The flowability accelerator is preferably contained in an amount of 0.001 to 100 parts by mass, more preferably 0.01 to 50 parts by mass based on 100 parts by mass of the inventive compound for forming a metal-containing film.
In addition, in the composition for forming a resist underlayer film of the present invention, it is preferable to use, as an additive for imparting filling and planarizing properties, for example, a liquid additive having a polyethylene glycol or polypropylene glycol structure, or a thermo-decomposable polymer having a weight reduction rate of 40% by mass or more on heating from 30° C. to 250° C. and a weight-average molecular weight of 300 to 200,000. This thermo-decomposable polymer preferably contains a repeating unit having an acetal structure represented by the following general formula (DP1) or (DP1a).
In the formula, Rio represents a hydrogen atom or a substituted or unsubstituted, saturated or unsaturated monovalent organic group having 1 to 30 carbon atoms. Y represents a saturated or unsaturated divalent organic group having 2 to 30 carbon atoms.
In the formula, R10a represents an alkyl group having 1 to 4 carbon atoms. Ya represents a saturated or unsaturated divalent hydrocarbon group having 4 to 10 carbon atoms and optionally having an ether bond. “n” represents an average repeating unit number of 3 to 500.
An acid generator (f) may be contained in the composition of the present invention for forming a resist underlayer film in order to promote the elimination reaction further. The acid generator (f) can be classified into those that generate an acid by thermal decomposition and those that generate an acid by optical irradiation; however, any acid generator can be added. Specific examples of the acid generator include the materials disclosed in paragraphs [0061] to [0085] of JP2007-199653A, but are not limited thereto.
One kind of the acid generator can be used, or two or more kinds can be used in combination. When an acid generator is contained, the contained amount is preferably 0.05 to 50 parts by mass, more preferably 0.1 to 10 parts by mass relative to 100 parts by mass of the compound (a) for forming a metal-containing film.
The present invention provides a method of forming, by using the above-described composition for forming a metal-containing film, a resist underlayer film of a multilayer resist film used in lithography or a filling film that serves as a planarizing film for the manufacture of semiconductor.
In the method for forming a resist underlayer film by using the inventive composition for forming a metal-containing film, the substrate to be processed is coated with the above-described composition for forming a metal-containing film by a spin-coating method or the like. Using the spin-coating method or the like ensures a desirable filling property. After spin-coating, baking (heating) is performed so as to evaporate the solvent and promote a crosslinking reaction to prevent mixing with the resist upper layer film and the resist middle layer film. The baking is preferably performed at a temperature of 100° C. or higher and 600° C. or lower for 10 to 600 seconds, more preferably at a temperature of 200° C. or higher and 500° C. or lower for 10 to 300 seconds. In consideration of influences on device damage, wafer deformation, and the like, the upper limit of the heating temperature in the wafer process of lithography is preferably not more than 600° C., and more preferably not more than 500° C.
In the method for forming a resist underlayer film where the inventive composition for forming a metal-containing film is used, a substrate to be processed may also be coated with the inventive composition for forming a metal-containing film by spin-coating or the like in the same manner as described above, and then the composition for forming a metal-containing film may be baked and cured under an atmosphere having an oxygen concentration of 0.1 volume % or more and 21 volume % or less to form a metal-containing film.
By baking the inventive composition for forming a metal-containing film in such an oxygen atmosphere, a sufficiently cured film can be obtained. The atmosphere during baking may be air; however, to prevent oxidation of the metal-containing film, it is preferable to enclose an inert gas, such as N2, Ar, or He, therein to reduce the amount of oxygen. Control of oxygen concentration is necessary to prevent oxidation; the oxygen concentration is preferably 1000 ppm or less, more preferably 100 ppm or less (volumetric basis). By thus preventing oxidation of the metal-containing film during the baking, the absorption does not increase and the etching resistance does not decrease, which is preferable.
The present invention provides, as a patterning process according to a two-layer resist process using the above-described composition for
The resist upper layer film in the two-layer resist process described above exhibits etching resistance with respect to chlorine-based gas. Therefore, the dry etching of the metal-containing film that is performed while using the resist upper layer film as a mask in the two-layer resist process is preferably performed using an etching gas mainly containing a chlorine-based gas.
The present invention provides, as a patterning process according to a three-layer resist process using the above-described composition for forming a metal-containing film, a patterning process including:
An example of a three-layer resist process specifically described with reference to
Next, as shown in
The silicon-containing resist middle layer film in the three-layer resist process exhibits etching resistance with respect to a chlorine-based gas and a hydrogen-based gas. Therefore, the dry etching of the metal-containing film that is performed while using the silicon-containing resist middle layer film as a mask in the three-layer resist process is preferably performed using an etching gas mainly containing a chlorine-based gas or a hydrogen-based gas.
As the silicon-containing resist middle layer film in the three-layer resist process, a polysiloxane-based middle layer film is also favorably used. This allows the silicon-containing resist middle layer film to possess an effect as an antireflective film, thereby suppressing reflection. When a material containing many aromatic groups and having a high etching selectivity with respect to the substrate is used as the organic film especially for 193-nm exposure, the k-value increases and thus the substrate reflection increases; however, the reflection can be suppressed by imparting absorption so that the silicon-containing resist middle layer film has an appropriate k-value. In this manner, the substrate reflection can be reduced to 0.5% or less. Preferably used as the silicon-containing resist middle layer film having an antireflective effect is a polysiloxane, which has a pendant anthracene for exposure at 248 nm or 157 nm, or a pendant phenyl group or a pendant light-absorbing group having a silicon-silicon bond for 193 nm exposure, and which is cross-linked by an acid or heat.
In addition, the present invention provides a patterning process by way of a four-layer resist process using such a composition for forming a metal-containing film, the patterning process including the steps of: forming a metal-containing film on a substrate to be processed by using the above-described composition for forming a metal-containing film; forming a silicon-containing resist middle layer film on the metal-containing film by using a silicon-containing resist middle layer film material;
Alternatively, an inorganic hard mask may be formed instead of the silicon-containing resist middle layer film. In this case, a semiconductor device circuit pattern can be formed on a substrate, at least, by:
As described above, when the inorganic hard mask is formed on the metal-containing film, a silicon oxide film, a silicon nitride film, and a silicon oxynitride film (SiON film) can be formed by a CVD method, an ALD method, etc. The method for forming the silicon nitride film is disclosed, for example, in JP2002-334869A and WO2004/066377A1. The film thickness of the inorganic hard mask is preferably 5 to 200 nm, more preferably 10 to 100 nm. The SiON film, which has a high function as an antireflective film, is the most preferably used as the inorganic hard mask. Since the substrate temperature increases to 300 to 500° C. when the SiON film is formed, the metal-containing film needs to withstand a temperature of 300 to 500° C. The composition for forming a metal-containing film used in the present invention has high heat resistance and can withstand a high temperature of 300 to 500° C. Thus, the metal-containing film formed by spin-coating and the inorganic hard mask formed by the CVD method or the ALD method can be combined.
A photoresist film may be formed on the inorganic hard mask as the resist upper layer film as described above. Alternatively, an organic antireflective film (BARC) or an adhesive film may be formed on the inorganic hard mask by spin-coating, and a photoresist film may be formed thereon. In particular, when a SiON film is used as the inorganic hard mask, the reflection can be suppressed by the two antireflective films, i.e., the SiON film and the BARC film, even in liquid immersion exposure at a high NA exceeding 1.0. Another merit of forming BARC resides in that it has an effect to reduce a footing profile of a photoresist pattern immediately above the SiON film.
In addition, the present invention provides a patterning process according to a multilayer resist process using such a composition for forming a metal-containing film. In this case, a semiconductor device circuit pattern can be formed on a substrate in the following manner: forming a resist underlayer film on a substrate to be processed; applying the inventive composition for forming a metal-containing film onto the resist underlayer film and then heating to form a metal-containing film;
A photoresist film may be formed on the metal-containing film as a resist upper layer film as described above. Alternatively, an organic adhesive film may be formed on the metal-containing film by spin-coating, and a photoresist film may be formed thereon.
As described above, when the resist underlayer film is formed on the substrate to be processed, the resist underlayer film can be formed by a method using a coating-type organic underlayer film material, a CVD method, an ALD method, or the like. Examples of the coating-type organic underlayer film material include resins and compositions disclosed in JP2012-001687A, JP2012-077295A, JP2004-264710A, JP2005-043471 A, JP2005-250434A, JP2007-293294A, JP2008-065303A, JP2004-205685A, JP2007-171895A, JP2009-014816A, JP2007-199653A, JP2008-274250A, JP2010-122656A, JP2012-214720A, JP2014-029435A, WO2012/077640A1, WO201 0/1471 55A1, WO2012/176767A1, JP2005-128509A, JP2006-259249A, JP2006-259482A, JP2006-293298A, JP2007-316282A, JP2012-145897A, JP201 7-1 19671 A, JP2019-044022A, etc.
The resist upper layer film in the multilayer resist process described above may be either α positive type or a negative type, and it is possible to use a film similar to the typically used photoresist composition. The prebaking, which is conducted after the spin-coating with the photoresist composition, is preferably performed at 60 to 180° C. for 10 to 300 seconds. Thereafter, exposure is conducted according to a usual manner, followed by post-exposure baking (PEB) and development, thereby obtaining a resist pattern. Although the thickness of the resist upper layer film is not particularly limited, the thickness is preferably 30 to 500 nm, particularly preferably 50 to 400 nm.
Furthermore, examples of light for exposure include high-energy beams at wavelengths of 300 nm or less, specifically excimer lasers at 248 nm, 193 nm, and 157 nm, soft X-rays at 3 to 20 nm, an electron beam, X-rays, and the like.
As the method for forming a pattern in the resist upper layer film, it is preferable to use a patterning process using a photolithography with a wavelength of 5 nm or more and 300 nm or less, a direct drawing using an electron beam, nanoimprinting, or a combination thereof.
The development method in the patterning process is preferably alkali development or development using an organic solvent.
Next, etching is performed while using the obtained resist pattern as a mask. The etching of a silicon-containing resist middle layer film or an inorganic hard mask in the three-layer resist process is performed while using the upper layer resist pattern as a mask by using a fluorocarbon-based gas. In this manner, a silicon-containing resist middle layer film pattern or an inorganic hard mask pattern is formed.
Next, the metal-containing film is etched while using the obtained silicon-containing resist middle layer film pattern or inorganic hard mask pattern as a mask. The etching of the metal-containing film is preferably performed using an etching gas mainly containing a chlorine-based gas.
The subsequent etching of the body to be processed may also be performed according to a usual manner. For example, in the case of a body to be processed made of SiO2, SiN or silica-based low dielectric constant insulating film, the etching is performed mainly based on a fluorocarbon-based gas. When the substrate is processed by way of etching with a fluorocarbon-based gas, the silicon-containing resist middle layer film pattern in the three-layer resist process is stripped simultaneously with the substrate processing.
The metal-containing film obtained by using the inventive composition for forming a metal-containing film is characterized by its excellent etching resistance at the time of etching of the body to be processed.
Examples of the body to be processed (substrate to be processed) include, but are not particularly limited to, substrates made of Si, α-Si, p-Si, SiO2, SiN, SiON, W, TiN, Al, etc., those in which the layers to be processed are formed on the substrate, and the like. Examples of the layers to be processed include various low-k films such as those made of Si, SiO2, SiON, SiN, p-Si, α-Si, W, W-Si, Al, Cu, Al—Si, and the like, and stopper films therefor, which can each be typically formed into a thickness of 50 to 10,000 nm, particularly 100 to 5,000 nm. When the layer to be processed is formed, the substrate and the layer to be processed are made of different materials.
In the patterning process using the inventive composition for forming a metal-containing film, it is preferable to use a substrate to be processed having a structure or step having a height of 30 nm or more. As described above, the inventive composition for forming a metal-containing film has excellent filling and planarizing properties, so that a flat cured film can be formed even when the substrate to be processed has a step (irregularities) or structure having a height of 30 nm or more. The height of the structure or step of the substrate to be processed is preferably 30 nm or more, more preferably 50 nm or more, and more preferably 100 nm or more. In the method of processing a stepped substrate having a pattern of the above-described height, filling and planarizing by forming a film of the inventive composition for forming a metal-containing film makes it possible to achieve a uniform film thickness in the subsequently formed resist middle layer film and resist upper layer film. Therefore, it is easy to ensure the exposure depth margin (DOF) at the time of photolithography, which is very desirable.
The present invention also provides, as a tone-reversal patterning process using such a composition for forming a metal-containing film, a tone-reversal patterning process including the steps of:
An example of formation of a tone-reversal pattern is specifically explained below by referring to
Next, as shown in
After applying the inventive composition for forming a metal-containing film onto the resist underlayer film pattern 7a formed of the coating-type organic underlayer film composition, heating is performed to cover the resist underlayer film pattern with a metal-containing film 8, thereby filling a space between the resist underlayer film patterns 7a formed of the coating-type organic underlayer film composition with the metal-containing film (
As described above, when the resist underlayer film is formed on the substrate to be processed, the resist underlayer film can be formed by a method using a coating-type organic underlayer film material, a CVD method, an ALD method, or the like. Examples of the coating-type organic underlayer film material include resins and compositions disclosed in JP2012-1687A, JP2012-77295A, JP2004-264710A, JP2005-043471 A, JP2005-250434A, JP2007-293294A, JP2008-65303A, JP2004-205685A, JP2007-171895A, JP2009-14816A, JP2007-199653A, JP2008-274250A, JP2010-122656A, JP2012-214720A, JP2014-29435A, WO2012/077640A1, WO201 0/1471 55A1, WO2012/176767A1, JP2005-128509A, JP2006-259249A, JP2006-259482A, JP2006-293298A, JP2007-316282A, JP2012-145897A, JP201 7-1 19671 A, JP2019-44022A, etc.
In the tone-reversal patterning process, after the obtained resist underlayer film pattern is coated with the composition for forming a metal-containing film, it is preferable to remove the metal-containing film by using a dry etching gas mainly containing a chlorine-based gas so as to expose the upper surface of the resist underlayer film pattern. Thereafter, the resist middle layer film or the hard mask middle layer film remaining on the resist underlayer film is removed by dry etching using a fluorocarbon-based gas, and the resist underlayer film pattern having an exposed surface is removed by dry etching using an oxygen-based gas to form a metal-containing film pattern.
In the tone-reversal patterning process described above, the resist underlayer film pattern preferably has a step or a structure with a height of 30 nm or more. As described above, the inventive composition for forming a metal-containing film has excellent filling and planarizing properties. Thus, even when the film to be processed has a step (irregularities) or a structure with a height of 30 nm or more, a flat cured film can be formed. The height of the structure or the step of the resist underlayer film pattern is preferably 30 nm or more, more preferably 50 nm or more, and still more preferably 100 nm or more. In the method of reversing the resist underlayer film pattern having a pattern with the above-described height, by performing filling and planarization by forming a film from the inventive composition for forming a metal-containing film, inversion/transfer of the pattern can be performed with a high degree of accuracy, which is very desirable. Reversing the resist underlayer film pattern by using the composition for forming a metal-containing film allows a desired resist pattern to be formed on a film to be processed with a high degree of accuracy due to the excellence in resistance in dry etching using a fluorocarbon-based gas relative to the resist underlayer film using a previously-known coating-type organic underlayer film material.
The present invention is more specifically described below with reference to Synthesis Examples, Comparative Synthesis Examples, Examples, and Comparative Examples. However, the present invention is not limited to these Examples. To obtain molecular weight and dispersity, weight-average molecular weight (Mw) and number-average molecular weight (Mn) on polystyrene basis were measured by gel permeation chromatography (GPC) using tetrahydrofuran as an eluent, and dispersity (Mw/Mn) was calculated from these values.
In the following Synthesis Examples and Comparative Examples, the tin compounds Sn ((Sn-1) to (Sn-3)), starting material group W ((W1) to (W10)), and starting material group G ((G-1) to (G-12)) shown below were used. The respective starting material groups are shown below.
Tin compounds Sn:
Starting material group W:
Starting material group G:
5.0 g of the tin compound (Sn-1), 4.6 g of the starting material (W1), and 100 g of toluene were added together, and a reaction was allowed to take place at 100° C. for 7 hours while removing tert-butyl alcohol. After the reaction, the solvent was removed under reduced pressure to give a compound (A-1).
(A-1): Mw=322, Mw/Mn=1.05
5.0 g of the tin compound (Sn-3), 6.0 g of the starting material (W2), and 100 g of toluene were added together, and a reaction was allowed to take place at 100° C. for 7 hours. After the reaction, the solvent was removed under reduced pressure to give a compound (A-2).
(A-2): Mw=344, Mw/Mn=1.08
5.0 g of the tin compound (Sn-2), 6.8 g of the starting material (W3), and 100 g of toluene were added together, and a reaction was allowed to take place at 130° C. for 7 hours while removing water. After the reaction, the solvent was removed under reduced pressure to give a compound (A-3).
(A-3): Mw=356, Mw/Mn=1.07
5.0 g of the tin compound (Sn-3), 6.0 g of the starting material (W2), 1.3 g of the starting material (G-1), and 100 g of toluene were added together, and a reaction was allowed to take place at 100° C. for 7 hours. After the reaction, the solvent was removed under reduced pressure to give a compound (A-4).
(A-4): Mw=401, Mw/Mn=1.24
(A-5) to (A-12) were obtained under the same reaction conditions as in Synthesis Example 4, except that the starting material group W and the starting material group G were used at the charging amounts shown in Tables 1-1 and 1-2. “-” indicates that the corresponding starting material group was not used. The weight-average molecular weight (Mw) and the dispersity (Mw/Mn) of these compounds were determined. Table 3 shows the results.
5.0 g of the tin compound (Sn-3) was stirred at room temperature, and 5.0 g of the starting material (G-10) was dropped thereto. After that, the temperature was raised to 80° C., and the mixture was stirred for 7 hours. After the completion of the reaction, the acrylic acid was removed under reduced pressure, and (R-1) was obtained.
5.0 g of the tin compound (Sn-2), 6.0 g of the starting material (G-11), and 100 g of toluene were added together, and a reaction was allowed to take place at 130° C. for 7 hours while removing water. After the reaction, the solvent was removed under reduced pressure to give (R-2).
5.0 g of the tin compound (Sn-2), 11.4 g of the starting material (G-12), and 100 g of toluene were added together, and a reaction was allowed to take place at 130° C. for 7 hours while removing water. After the reaction, the solvent was removed under reduced pressure to give (R-3).
Table 2 shows the charging amounts in Comparative Synthesis Examples 1 to 3 and the synthesized compounds. In addition, the weight-average molecular weight (Mw) and the dispersity (Mw/Mn) of these compounds were determined. Table 3 shows the results.
As a compound having a different metal from the inventive compound for forming a metal-containing film, a titanium compound reported in [Synthesis Example A-II] of JP6189758B2 was synthesized. 2-propanol (IPA) solution (500 g) of deionized water (27 g) was dropped while stirring into an IPA solution (500 g) of a titanium tetraisopropoxide (manufactured by Tokyo Chemical Industry Co., Ltd.) (284 g) at room temperature for 2 hours. 2-methyl-2,4-pentanediol (120 g) was added to the obtained solution and agitated at room temperature for 30 minutes. After the solution was concentrated under reduced pressure at 30° C., it was heated to 60° C. and heating was continued under reduced pressure to generate no distillate. Then, PGMEA (1,200 g) was added thereto and heated under reduced pressure at 40° C. until no IPA was distilled to obtain a PGMEA solution of a titanium-containing compound (R-4) (1,000 g) (compound concentration: 20 mass %). The molecular weight of the compound measured in terms of polystyrene was Mw=1,100.
Under a nitrogen atmosphere, 160.2 g of 1,5-dihydroxynaphthalene, 56.8 g of formaldehyde, and 300 g of propylene glycol monomethyl ether (PGME) were added together, and homogenized at an internal temperature of 100° C. After that, a mixed solution of 8.0 g of p-toluenesulfonic acid monohydrate and 8.0 g of PGME that had been mixed and homogenized beforehand was added dropwise slowly, and a reaction was allowed to take place at an internal temperature of 80° C. for 8 hours. After the reaction was completed, the product was cooled to room temperature, and 2,000 ml of MIBK was added thereto. The product was washed six times with 500 ml of pure water, and the organic layer was evaporated under reduced pressure to dryness. After adding 300 g of THF to the residue to yield a homogeneous solution, a crystal was precipitated in 2,000 g of hexane. The precipitated crystal was separated by filtration, washed twice with 500 g of hexane, and collected. The collected crystal was vacuum-dried at 70° C., thereby obtaining a resin (R-5).
The weight-average molecular weight (Mw) and the dispersity (Mw/Mn) were determined by GPC, and the following results were obtained. (R-5): Mw=3,300, Mw/Mn=2.54
Compositions UDL-1 to -16 for forming a metal-containing film used in Examples 1-1 to 1-19 and compositions (comparative UDL-1 to -5) for forming a metal-containing film used in Comparative Examples 1-1 to 1-4 were prepared in the following manner.
The compound (A-1) for forming a metal-containing film was dissolved at a ratio shown in Table 4 in a mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) and cyclohexanone (CyHO) containing 0.5 mass % of a surfactant FC-4430 (manufactured by Sumitomo 3M Limited), and the solution was filtered through a 0.2-μm membrane filter to prepare a composition (UDL-1) for forming a metal-containing film.
Each chemical liquid was prepared in the same manner as UDL-1, except that the type and the contained amount of each component were as shown in Table 4. In Table 4, “-” indicates that the corresponding component was not used. The following formula (C-1) was used for the crosslinking agent, 1,6-diacetoxyhexane (boiling point: 260° C.) was used as the high-boiling-point solvent (D-1), a polymer (F-1) for a flowability accelerator was used, and the formula (TAG-1), shown later, was used for the thermal acid generator (TAG).
The crosslinking agent (C-1) used in a composition for forming a metal-containing film is shown below.
Under a nitrogen atmosphere, 20.0 g of cresol novolak, 27.6 g of potassium carbonate, and 100 g of DMF were added together to form a homogeneous dispersion at an internal temperature of 50° C. 11.9 g of propargyl bromide was slowly added thereto, and a reaction was allowed to take place at an internal temperature of 50° C. for 24 hours. To the reaction solution, 300 ml of methyl isobutyl ketone and 300 g of pure water were added to dissolve the precipitated salt, and then the separated aqueous layer was removed. Furthermore, the organic layer was washed six times with 100 g of a 3% aqueous nitric acid solution and 100 g of pure water, and then the organic layer was evaporated under reduced pressure to dryness to obtain a resin (F-1).
The weight-average molecular weight (Mw) and the dispersity (Mw/Mn) were determined by GPC, and the following results were obtained. (F-1): Mw=8,500, Mw/Mn=3.46
The thermal acid generator (TAG-1) used in a composition for forming a metal-containing film is shown below.
As shown in Table 4, it was possible to prepare the inventive compositions for forming a metal-containing film (Examples 1-1 to 1-12) by a PGMEA-containing composition, and it was observed that these compositions had better solvent solubility than comparative UDL-2, which had two styrenecarboxylic acids bonded and could not be prepared by a PGMEA-containing composition. Meanwhile, it was possible to prepare UDL-4 to UDL-12, which were obtained by allowing the starting material group W and the starting material group G to react, by a composition of only PGMEA, and it was observed that the compositions had even better solvent solubility. This is thought to be because of the symmetry of the molecules being broken.
Each of the compositions (UDL-1 to -16 and comparative UDL-1 to −5) for forming a metal-containing film prepared as described above was respectively applied onto a silicon substrate and baked at 100° C. for 60 seconds, and then the film thickness (a [nm]) was measured. Subsequently, after baking at the baking temperature shown in Table 5 for 60 seconds, the film thickness (b [nm]) was measured, and the difference between the film thicknesses (film remaining percentage: (b/a)×100) before and after the additional baking was determined.
Furthermore, a PGMEA solvent was dispensed thereon, left to stand for 30 seconds, spin-dried, and baked at 100° C. for 60 seconds to evaporate the PGMEA. The film thickness (c [nm]) was then measured. The difference between the film thicknesses (film remaining percentage: (c/b)×100) before and after the PGMEA treatment was determined. The following Table 5 shows the results.
As shown in Table 5, the inventive compositions for forming a metal-containing film (Example 1-1 to 1-12) had a film remaining percentage ((b/a)×100) of more than 55% after the additional high-temperature baking, and it was shown that the compositions had the high-temperature baking resistance required in resist underlayer films. On the other hand, in Comparative Example 1-3, where there was no catechol/diol structure, the film remaining percentage ((b/a)×100) after the additional high-temperature baking was 43%, and it was confirmed that heat resistance was poor. Meanwhile, comparing Examples 1-17 to 1-19 with Comparative Example 1-4, where additional high-temperature baking was performed at 350° C., the film remaining percentage was 8% in Comparative Example 1-4, and hardly any film remained, but in Examples 1-17 to 1-19, the film remaining percentage was respectively 35%, 38%, and 39%, and it was observed that more than 30% of the film remained. Thus, it was revealed that the compositions had heat resistance that made it possible to form a film even under a very-high-temperature baking condition of 350° C. This is thought to be because the organic ligand is bonded to the tin atom at two points in the inventive compounds like in a chelate. Furthermore, the films subjected to an additional high-temperature baking treatment had a film remaining percentage ((c/b)×100) of more than 99% after the PGMEA rinsing treatment, and it can be observed that a crosslinking reaction occurred and sufficient solvent resistance was exhibited. Meanwhile, comparing UDL-15, which contained the crosslinking agent (C-1), with UDL-11, which did not contain a crosslinking agent, the film remaining percentage after the baking was increased from 61% to 65%. This is thought to have resulted from the crosslinking occurring efficiently because of the crosslinking agent and sublimation products being suppressed. Meanwhile, comparing UDL-4 with UDL-13, containing the thermal acid generator (TAG-1), UDL-4 had a film remaining percentage ((c/b)×100) of 99.7% after the PGMEA rinsing after the baking at 250° C., whereas UDL-13 had a film remaining percentage ((c/b)×100) of 100% after the PGMEA rinsing after the baking at 200° C., and the curability was increased. This is thought to have resulted from the removal of leaving groups and the crosslinking reaction caused by the removal occurring efficiently due to the thermal acid generator being contained. On the other hand, comparative UDL-1 and UDL-2 had a film remaining percentage ((b/a)×100) of less than 5% after the additional high-temperature baking. This is thought to have resulted from heat resistance being insufficient, although a crosslinking group was contained, so that the molecules were decomposed before the crosslinking reaction progressed and were sublimed.
Meanwhile, in Comparative Example 1-4, where the titanium compound reported in [Synthesis Example A-II] of JP6189758B2 was used as a compound having a different metal from the inventive compound for forming a metal-containing film, sufficient solvent resistance was exhibited, but the difference between the film thicknesses before and after the additional high-temperature baking was large, and it was shown that volume shrinkage due to high-temperature baking was greater than in the inventive compounds for forming a metal-containing film.
Each of the compositions (UDL-1 to −16 and comparative UDL-3 to −5) for forming a metal-containing film that had favorable film-formability after the additional baking in the solvent resistance evaluation was respectively applied onto an SiO2 wafer substrate having a dense line-and-space pattern (line width=40 nm, line depth=120 nm, distance between the centers of two adjacent lines=80 nm), followed by heating at the temperature shown in Table 6 for 60 seconds by using a hot plate to form a metal-containing film having a film thickness of 100 nm. The substrate used was a base substrate 9 (SiO2 wafer substrate) having a dense line-and-space pattern shown in
It was successfully confirmed that, as shown in Table 6, in Examples 2-1 to 2-16 using the compositions (UDL-1 to −16) of the present invention for forming a resist metal-containing film, it was possible to fill the dense line-and-space pattern without the generation of voids, and excellent filling property was provided. On the other hand, voids were observed at the bottom of the pattern in Comparative Example 2-2, using the titanium compound reported in [Synthesis Example A-II] of JP6189758B2. It is conjectured that voids were generated because volume shrinkage due to high-temperature baking was great, as observed in the solvent resistance evaluation.
Regarding base substrates 11 (SiO2 wafer substrates) each having a dense line-and-space pattern shown in
As shown in Table 7, it was observed that the step in the film between the patterned portion and the non-patterned portion was small and the planarization property was better in Examples 3-1 to 3-16, where the compositions (UDL-1 to −16) of the present invention for forming a resist metal-containing film were used, than in Comparative Example 3-2, where the titanium compound reported in [Synthesis Example A-II] of JP6189758B2 was used, and Comparative Example 3-3, where the organic resist underlayer film material was used. It was also observed that the inventive compositions had better flatness even when compared with Comparative Example 3-1, where a similar tin-containing compound was used. This is thought to be because the inventive compounds have an asymmetrical structure, and contribute to the enhancement of thermal flowability.
Furthermore, in Examples 3-14 and 3-16, where a high-boiling-point solvent (D-1) and a flowability accelerator (F-1) were respectively contained, better planarizing property was exhibited compared to Example 3-4 and Example 3-11, which did not contain the additives. It can be seen that by using a high-boiling-point solvent (D-1) or a flowability accelerator (F-1), the thermal flowability of the compound for forming a metal-containing film can be further enhanced.
Each of the compositions (UDL-3, UDL-7, UDL-9, and comparative UDL-3 to −5) for forming a metal-containing film that had good film-formability after the additional baking in the solvent resistance evaluation was respectively applied onto a silicon substrate and heated by using a hot plate at the temperature shown in Table 8 for 60 seconds to form a metal-containing film having a film thickness of 200 nm, etching tests were conducted with a CF-based gas and an 02-based gas under the following conditions, and the difference in the film thicknesses of the organic film before and after the etching was determined. Table 8 shows the results. For the etching, a dry etching apparatus TE-8500, manufactured by Tokyo Electron Ltd., was used.
Conditions of etching with a CF4-based gas were as follows.
As shown in Table 8, it was shown that better etching resistance to the CF-based gas was exhibited and 02 etching resistance was even better in Examples 4-1 to 4-3, where the compositions (UDL-3, -7, and -9) of the present invention for forming a resist metal-containing film were used, Comparative Example 4-1, where a similar composition (comparative UDL-3) for forming a metal-containing film was used, and Comparative Example 4-2, where a titanium compound (comparative UDL-4) was used, than in Comparative Example 4-3, where comparative UDL-5, being an organic resist underlayer film material, was used.
Each of the compositions (UDL-3, UDL-7, UDL-9, and comparative UDL-4 and -5) for forming a metal-containing film that had favorable film-formability after the additional baking in the solvent resistance evaluation was respectively applied onto an SiO2 wafer substrate having a trench pattern (trench width: 10 μm, trench depth: 0.10 μm), and baked at 250° C. for 60 seconds in the atmosphere to form a metal-containing film having a thickness of 100 nm. A silicon-containing resist middle layer film material (SOG-1) was applied thereto, followed by baking at 220° C. for 60 seconds to form a resist middle layer film having a thickness of 30 nm. A monolayer resist for ArF as a resist upper layer film material was applied thereto, followed by baking at 105° C. for 60 seconds to form a photoresist film having a thickness of 100 nm. A liquid immersion top coat composition (TC-1) was applied to the photoresist film, followed by baking at 90° C. for 60 seconds to form a top coat having a thickness of 50 nm.
The silicon-containing resist middle layer film material (SOG-1) was prepared by dissolving a polymer represented by an ArF silicon-containing middle layer film polymer (SiP1) and a crosslinking catalyst (CAT1) in an organic solvent containing 0.1 mass % of FC-4430 (manufactured by Sumitomo 3M Limited) in the proportion shown in Table 9; and filtering the solution through a filter made of a fluororesin and having a pore size of 0.1 μm.
The structural formulae of the ArF silicon-containing middle layer film polymer (SiP1) and the crosslinking catalyst (CAT1) used are shown below.
The resist upper layer film material (monolayer resist for ArF) was prepared by dissolving a polymer (RP1), an acid generator (PAG1), and a basic compound (Amine1), each in the proportion shown in Table 10, in a solvent containing 0.1% by mass of a surfactant FC-4430 (manufactured by Sumitomo 3M Limited), and filtering the solution through a 0.1-μm filter made of a fluororesin.
The polymer (RP1), the acid generator (PAG1), and the basic compound (Amine1) used for the resist upper layer film material (monolayer resist for ArF) are shown below.
The liquid immersion top coat composition (TC-1) was prepared by dissolving a top coat polymer (PP1) in an organic solvent at the proportion shown in Table 11, and filtering the solution through a 0.1-μm filter made of a fluororesin.
The polymer (PP1) used for the liquid immersion top coat composition (TC-1) is shown below.
Then, the substrate was exposed to light with an ArF liquid immersion exposure apparatus (NSR-S610C manufactured by Nikon Corporation, NA: 1.30, σ: 0.98/0.65, 35° s-polarized dipole illumination, 6% halftone phase shift mask), baked at 100° C. for 60 seconds (PEB), and developed with a 2.38% by mass of aqueous solution of tetramethylammonium hydroxide (TMAH) for 30 seconds, thereby obtaining a 55 nm 1:1 positive line-and-space pattern (a resist pattern).
Subsequently, the silicon-containing resist middle layer film material (SOG-1) was etched by dry etching while using the resist pattern as a mask to form a hard mask pattern. The metal oxide film was then etched while using the obtained hard mask pattern as a mask to form a metal oxide film pattern, and the SiO2 film was etched while using the obtained metal oxide film pattern as a mask. As the etching apparatus, ULVAC CE-3001 was used, and the etching conditions were as follows.
Conditions in transferring resist pattern to silicon-containing resist middle
Table 12 shows the results obtained by observation of the pattern cross section with an electron microscope (S-4700) manufactured by Hitachi, Ltd.
As shown in Table 12, in Examples 5-1 to 5-3, where the compositions (UDL-3, -7, and -9) of the present invention for forming a metal oxide film were used, the resist upper layer film pattern was successfully transferred to the substrate in the end in every case. Thus, it was confirmed that the composition of the present invention for forming a metal oxide film can be used suitably for fine processing using a multilayer resist method. On the other hand, in Comparative Example 5-1, where the performance in the filling property evaluation and the planarizing property evaluation was found to be insufficient, pattern collapse occurred during patterning, and it was not possible to obtain a favorable pattern in the end. Meanwhile, in Comparative Example 5-2, where there were no problems in the filling property and planarizing property evaluations but insufficient performance was observed in the dry etching resistance evaluation, distortion of the pattern profile occurred at the time of pattern processing, and it was not possible to obtain a favorable pattern in the end.
From the above, the compound of the present invention for forming a metal oxide film is an organotin compound having both high thermal flowability and high thermosetting property, so that a composition for forming a metal-containing film containing the compound can provide a metal-containing film, such as a resist underlayer film material, having better dry etching resistance than conventional organic underlayer film materials and also having high filling and planarizing properties. Therefore, such a composition is extremely useful as a resist underlayer film material used in a multilayer resist method and an inverting agent used in a tone-reversal etching method.
The present description includes the following embodiments.
wherein R1 and R2 each independently represent an organic group or a halogen atom; and W represents a divalent organic group represented by the following general formula (W-1) or (W-2),
wherein “I” represents an integer of 2 or 3; R3 and R4 each independently represent a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, a hydrogen atom, or a halogen atom, or the R3 and the R4 on a single carbon atom form a carbonyl group together with the carbon atom bonded thereto, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group, the R3 and the R4 on a single carbon atom optionally being bonded to each other to form a cyclic structure, and the R3 and the R4 on adjacent carbon atoms optionally being bonded to each other to form a cyclic structure; each R5 independently represents a substituted or unsubstituted, linear, branched, or cyclic alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkynyl group having 2 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted heteroalkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a thiol group, a hydroxy group, an amino group, or a halogen atom, the alkyl group, the alkenyl group, the alkynyl group, and the alkoxy group optionally having an ester group or an amide group; “n” represents an integer of 0 or 1; “m” represents an integer of 0 to 6; and represents an attachment point to —OSn.
wherein YA1 and YA2 are each identical to or different from each other and represent a substituted or unsubstituted saturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms; RA represents a hydrogen atom, a substituted or unsubstituted saturated divalent organic group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent organic group having 2 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms; RA1 represents an organic group whose protecting group is to be removed by an action of an acid, heat, or both to generate one or more hydroxy groups or carboxyl groups, RA1 being represented by one of the following general formulae (1); and “*” represents an attachment point to the carbonyl group,
wherein RA2 represents an organic group whose protecting group is to be removed by an action of an acid, heat, or both; and “*” represents an attachment point to YA1 or YA2,
wherein X represents a divalent organic group having 1 to 31 carbon atoms; B represents the following general formula (B); and “*” represents an attachment point to the carbonyl group,
wherein YB represents a substituted or unsubstituted saturated divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted unsaturated divalent aliphatic hydrocarbon group having 2 to 20 carbon atoms, a substituted or unsubstituted divalent aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted divalent arylalkyl group having 7 to 31 carbon atoms, YB optionally being bonded to an adjacent group via an oxygen atom or an NH group; RB represents a hydroxy group or a structure represented by one of the following general formulae (B-1) to (B-3); and “*” represents an attachment point to the carbonyl group,
wherein RB1 represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms; “q” represents 0 or 1; and “*” represents an attachment point to YB,
wherein X represents a divalent organic group having 1 to 31 carbon atoms; C represents a group represented by one of the following general formulae (C-1) to (C-4); and “*” represents an attachment point to the carbonyl group,
wherein RC1s each independently represent a hydrogen atom or a methyl group and are identical to or different from each other in a single formula; RC2 represents a hydrogen atom, a substituted or unsubstituted, saturated or unsaturated monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted arylalkyl group having 7 to 31 carbon atoms; and “*” represents an attachment point to the carbonyl group.
wherein Ra, Rb, and Rc each represent a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms, Ra and Rb optionally being bonded to each other to form a cyclic substituent; and “*1” and “*2” each represent an attachment point to the carbonyl group, substitution positions of “*1” and “*2” optionally being reversed.
It should be noted that the present invention is not limited to the above-described embodiments. The embodiments are just examples, and any examples that have substantially the same feature and demonstrate the same functions and effects as those in the technical concept disclosed in claims of the present invention are included in the technical scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-138373 | Aug 2023 | JP | national |
