Patent Application
20230341776
This application claims priority to Korean Patent Application No. 10-2022-0051653, filed on Apr. 26, 2022, in the Korean Intellectual Property Office, the entire contents of which are hereby incorporated by reference.
The present disclosure relates to a resist compound, and more particularly, relates to a resist compound used for manufacturing a semiconductor device.
Photolithography may include irradiating light of a certain wavelength to a resist layer to cause a change in a chemical structure of the resist layer and selectively removing an exposed portion or an unexposed portion by using a difference in solubility between the exposed and unexposed portion of the resist layer. Recently, as a semiconductor device has become highly integrated and miniaturized, it is required that components of the semiconductor device have fine pitch and width. As a result, the importance of a resist compound for forming a fine pattern is increasing.
An embodiment provides a resist compound having high photosensitivity characteristics and high reactivity.
An embodiment provides a method for forming a fine and uniform pattern and a resist compound used therein.
According to an embodiment, a resist compound is represented by Formula 1.
In Formula 1, “R1” is an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, or a hydrocarbon ring group having 3 to 12 carbon atoms, and “A” bonded to “R1” is O or NR2, wherein “R2” is hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, or a hydrocarbon ring group having 3 to 12 carbon atoms.
According to an embodiment, a resist composition includes a resist compound represented by Formula 1 and an organic solvent.
In Formula 1, “R1” is an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, or a hydrocarbon ring group having 3 to 12 carbon atoms, and “A” bonded to “R1” is O or NR2, wherein “R2” is hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, or a hydrocarbon ring group having 3 to 12 carbon atoms.
According to an embodiment, a method of forming a pattern includes forming a resist layer by applying a resist composition including the resist compound on a substrate, performing an exposure process of irradiating light onto the resist layer, and performing a developing process on the resist layer to form a resist pattern.
Example embodiments will be more clearly understood from the following brief description taken in conjunction with the accompanying drawings. The accompanying drawings represent non-limiting, example embodiments as described herein.
As used herein, an alkyl group may be a linear alkyl group, a branched alkyl group, or a cyclic alkyl group. The number of carbon atoms in the alkyl group is not particularly limited, but may be an alkyl group having 1 to 12 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an i-butyl group, a 2-ethylbutyl group, a 3,3-dimethylbutyl group, an n-pentyl group, an i-pentyl group, a neopentyl group, a t-pentyl group, a cyclopentyl group, and the like, but are not limited thereto.
As used herein, an alkenyl group may be a linear alkenyl group or a branched alkenyl group. The number of carbon atoms in the alkenyl group is not particularly limited, but may be 1 or more and 12 or less. Examples of the alkenyl group include a 1-butenyl group, a 1-pentenyl group, and a 1,3-butadienyl group, a vinyl group, and the like, but are not limited thereto.
As used herein, the alkenyl group may include an allyl group.
As used herein, a hydrocarbon ring includes an aliphatic hydrocarbon ring and an aromatic hydrocarbon ring. The hydrocarbon ring may be monocyclic or polycyclic. The number of carbon atoms in the aromatic hydrocarbon ring is not particularly limited, but may have 3 to 12 carbon atoms. As used herein, the aromatic ring may include an aromatic hydrocarbon ring. The aromatic hydrocarbon ring may be an aryl group.
In the present specification, examples of halogen include, but are not limited to, fluorine (F), chlorine (Cl), bromine (Br), and iodine (I).
Unless otherwise defined in a chemical formula of the present specification, when a chemical bond is not drawn at a position where a chemical bond may be drawn, it can mean that a hydrogen atom is bonded to the position.
As used herein, the like elements are designated with the same reference numerals over the present specification.
Hereinafter, a resist compound and a resist composition including the same according to embodiments will be described.
According to an embodiment, a resist composition may be used for forming a pattern or for manufacturing a semiconductor device. For example, the resist composition may be used in a patterning process for manufacturing a semiconductor device. The resist composition includes a resist compound. The resist compound may be an extreme ultraviolet (EUV) resist compound or an electron beam (e-beam) resist compound. Extreme ultraviolet may refer to ultraviolet radiation having a wavelength of 10 nm to 124 nm, specifically, a wavelength of 13.0 nm to 13.9 nm, and more specifically, a wavelength of 13.4 nm to 13.6 nm. The resist compound may be a metal chalcogen compound. In some embodiments, the resist compound may be represented by Formula 1 below.
In Formula 1, “R1” is an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, or a hydrocarbon ring group having 3 to 12 carbon atoms, and “A” bonded to “R1” is O or NR2, wherein “R2” is hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, or a hydrocarbon ring group having 3 to 12 carbon atoms.
For example, in Formula 1, “R1” may be an alkyl group having 1 to 12 carbon atoms. Specifically, “R1” may be an alkyl group having 1 to 5 carbon atoms. “R1” of Formula 1 may be a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group, but is not limited thereto. When the number of carbon atoms in “R1” is excessively large (e.g., 13 or more), reactivity of the resist compound to extreme ultraviolet may decrease.
For example, a compound represented by Formula 1 may be Ag—O-alkyl dithiocarbonate or Ag—N-alkyl dithiocarbonate, but is not limited thereto.
The compound represented by Formula 1 may be represented by Formula 2 or Formula 3 below.
In Formula 2, “R1” is an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, or a hydrocarbon ring group having 3 to 12 carbon atoms.
In Formula 3, “R1” is an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, or a hydrocarbon ring group having 3 to 12 carbon atoms, and “R2” is hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 1 to 12 carbon atoms, or a hydrocarbon ring group having 3 to 12 carbon atoms.
According to embodiments, a compound represented by Formula 1 includes silver (Ag). Silver (Ag) may be well combined with an alkyl dithiocarbonate. The alkyl dithiocarbonate may be O-alkyl dithiocarbonate or N-alkyl dithiocarbonate. For example, silver (Ag) may be bonded with an alkyl dithiocarbonate. The bonding may include, but is not limited to, a chemical bond such as a covalent bond. The compound represented by Formula 1 included silver (Ag), and thus the resist compound according to embodiments may well form a resist layer by a coating process.
The resist compound according to embodiments may have high absorbance with respect to light. The resist compound may be reactive to light. For example, a reaction of the resist compound by light irradiation may be represented by Reaction Formula 1 below. The light may be extreme ultraviolet (EUV) or an electron beam (e-beam) as described above.
The resist compound according to embodiments may be mixed with a solvent to prepare a resist composition. In this case, the solvent may be an organic solvent. The organic solvent may include an alcohol solvent, a nitrile solvent, an acetate solvent, a halogenated alkyl solvent, an aromatic ether solvent, an amide solvent, or mixtures thereof. The alcohol solvent may include ethanol. The nitrile solvent may include acetonitrile. The acetate solvent may include, for example, propylene glycol methyl ether acetate. The halogenated alkyl solvent may include chloroform. The aromatic ether solvent may include an anisole solvent. The amide solvent may include dimethylformamide.
The resist composition according to embodiments may not include a photoacid generator.
A resist layer may be formed using the resist composition according to embodiments.
Hereinafter, a method of manufacturing a resist compound according to embodiments will be described.
Preparation of the resist compound represented by Formula 2 may proceed as shown in Reaction Formula 2 below.
In Reaction Formula 2, “R1” is as defined in Formula 2.
The preparation of the resist compound represented by Formula 3 may proceed as shown in Reaction Formula 3 below.
In Reaction Formula 3, “R1” is as defined in Formula 3.
Hereinafter, a method for preparing a resist compound and a pattern forming method using the same according to embodiments will be described.
Referring to
A resist composition according to embodiments may be prepared. The resist composition may include a resist compound represented by Formula 1 and an organic solvent. The resist composition may be applied on the lower layer 200 to form the resist layer 300. The resist composition may be applied by spin coating.
A pre-bake process may be further performed on the resist layer 300. The pre-bake process may include heat-treating the resist layer 300 under a first temperature condition. The first temperature may be 80° C. to 150° C. The resist compound according to embodiments may have thermal stability under the first temperature condition. Accordingly, damage or deformation of the resist layer 300 in the pre-bake process may be prevented.
Referring to
A second portion 320 of the resist layer 300 may not be exposed to the light 500. A chemical structure of the resist compound in the second portion 320 of the resist layer 300 may not be changed. Accordingly, after irradiation of the light 500 is completed, the first portion 310 of the resist layer 300 may have a different chemical structure from that of the second portion 320.
The resist compound according to embodiments may have high absorbance and high reactivity with respect to the light 500, and thus the first portion 310 of the resist layer 300 may be formed at a desired position. Undesirable errors in the exposure process may be prevented.
According to embodiments, the resist compound includes silver (Ag), and may be a non-chemically amplified resist (non-CAR) compound. For example, the structure of the first portion 310 of the resist layer 300 may be directly changed by the light. The resist layer 300 may not include a separate photoacid generator. Accordingly, a shape of the first portion 310 of the resist layer 300 or a resist pattern 300P to be described later in
In some embodiments, a post-exposure bake (PEB) may be further performed on the resist layer 300. The post-exposure bake process may include heat treatment at a second temperature condition. The second temperature may be higher than the first temperature. For example, the second temperature may be 150° C. to 250° C. The resist compounds according to embodiments may have thermal stability under the second temperature condition. Accordingly, during the post-exposure bake process, the shape of each of the first portion 310 and the second portion 320 of the resist layer 300 may not be deformed.
Thereafter, the photomask 400 may be removed.
Referring to
The resist compound according to embodiments has high absorbance and high reactivity with respect to the light (500 in
As described in
Referring to
According to embodiments, the lower pattern 200P may be a component of a semiconductor device. For example, the lower pattern 200P may be a semiconductor pattern, a conductive pattern, or an insulating pattern in the semiconductor device.
Referring to
Referring to
Referring to
Hereinafter, with reference to the Experimental Examples of embodiments, preparation of a resist composition and a formation of a resist pattern will be described.
Deionized water (DI water) was added to and mixed with a starting material of Table 1 and silver nitrate in a molar ratio of 1:1 to prepare a resist compound. The starting material was potassium O-alkyl dithiocarbonate. The resist compound was added to an organic solvent to prepare a resist composition.
A resist layer was formed by coating the resist composition on a silicon substrate. In this case, a Si3N4 wafer having a size of 2 cm×2 cm was used as a silicon substrate.
0.05 mol of Ag2O was mixed in a solution of CS2 and 1-buytlamine having a molar ratio of 1:1 in chloroform to carry out a reaction shown in Reaction Formula 3A below.
A resist layer was formed on a silicon substrate in the same manner as in Experimental Example 1, except that the resist composition of Experimental Example 5 was used.
Ethanol 4 ml, methacrylic acid 4 ml, and HCl 1.8 ml (0.37M) were mixed and stirred, and then silver methacrylate powder (0.45M) and ethanolamine 0.27 ml were mixed therein to prepare a resist composition of Comparative Example 1.
A resist layer was formed on a silicon substrate in the same manner as in Experimental Example 1, except that the resist composition of Comparative Example 1 was used.
Silver trifluoroacetate was prepared from trifluoroacetate. Silver trifluoroacetate was dissolved in dimethylformamide (hereinafter, DMF) to prepare a resist composition of Comparative Example 2.
A resist layer was formed on a silicon substrate in the same manner as in Experimental Example 1, except that the resist composition of Comparative Example 2 was used.
Table 1 shows starting materials used in the preparation of the resist compounds of Experimental Examples 1 to 5, Comparative Example 1, and Comparative Example 2.
Table 2 shows resist layer coating evaluation results and EUV reactivity evaluation results of Experimental Examples and Comparative Examples.
Referring to Table 2, the resist layers prepared using the resist compositions of Experimental Example 1, Experimental Example 2, and Experimental Example 3 were evaluated to be well coated. The resist compositions of Experimental Examples 1 and 2 were reactive to EUV. In the case of Comparative Example 1, the resist layer was non-reactive to EUV. When the resist composition of Comparative Example 2 was used, the coating characteristics of the resist layer were poor. In the case of Comparative Example 2, the resist layer was poor, and thus EUV characteristics of the resist layer could not be evaluated.
Table 3 shows the results of measuring particle sizes of the resist compositions of the Experimental Examples and Comparative Examples.
Referring to Table 3, the resist compositions of Experimental Example 1, Experimental Example 2, Experimental Example 3, Experimental Example 4, and Experimental Example 5 were evaluated to have relatively small particle sizes.
When the particle size of the resist compositions is reduced, the resist layer prepared using the resist composition may be finely patterned. The resist pattern including the resist compositions may have improved line width roughness (LWR) characteristics.
Referring to
The resist layer manufactured using the resist compound according to embodiments may have thermal stability, and thus may not be deformed in a pre-bake process and a post-exposure baking process.
Table 4 shows the results of measuring a thickness and thickness deviation of resist layers prepared using the resist compositions of Experimental Examples 1 and 2, depending on a spin coating speed of the resist layer. Here, in Experimental Example 1, dimethylformamide was used as a solvent, and in Experimental Example 2, chloroform was used as a solvent.
Referring to Table 4, the resist layers prepared using the resist composition of Experimental Examples 1 and 2 may have a thin thickness and a small thickness deviation.
Table 5 shows the results of evaluating solubility of resist compounds and coating uniformity of resist layers depending on a type of solvent. Here, the resist compound of Experimental Example 1 and the resist compound of Experimental Example 2 were used for evaluation.
Referring to Table 5, the resist compound of Experimental Example 1 had high solubility in chloroform solvent, the mixed solvent of chloroform and anisole, and dimethylformamide solvent. When the resist composition including the resist compound of Experimental Example 1 was used, the resist layer was uniformly formed.
The resist compound of Experimental Example 2 had high solubility in chloroform solvent. When the resist composition including the resist compound of Experimental Example 2 was used, the resist layer was uniformly formed.
Table 6 shows whether a resist compound is prepared depending on the type of metal and results of evaluating characteristics of a resist layer prepared by using the resist compound. Whether the resist compound is prepared was evaluated by whether metal-O-dialkyl dithiocarbonate is prepared. In Table 6, a poor resist layer may include that the resist layer cannot be formed because the resist layer material is not prepared. The poor resist layer may include that the resist layer is not uniformly formed.
Referring to Table 6, it may be confirmed that silver reacts with alkyl dithiocarbonate to prepare a resist compound. In addition, the resist compound containing silver (Ag) was evaluated as being good for forming a resist layer. For example, a resist compound including silver (Ag) may form a uniform resist layer.
Table 7 shows the results of evaluating photosensitivity characteristics of the resist layers of Experimental Examples 1 and 2 with respect to EUV. The photosensitivity is evaluated by the dose when the measured thickness of the resist layer is 50% of the initial thickness of the resist laver.
Referring to
Table 8 shows a chemical bond corresponding to a peak wavelength in a Fourier transform infrared spectrometer.
Referring to
Referring to
According to embodiments, the resist compound may react with light to change the chemical structure of the resist compound. The reaction of the resist compound by irradiation with EUV may be represented by Reaction Formula 1. For example, C2H4, carbonyl sulfide, and Ag2S may be produced by the reaction of the resist compound.
According to the embodiment, the resist composition may have the high absorbance and high reactivity to electron beams and/or extreme ultraviolet. Accordingly, the resist layer prepared using the resist composition may be well patterned.
While example embodiments have been particularly shown and described, it will be understood by one of ordinary skill in the art that variations in form and detail may be made therein without departing from the spirit and scope of the attached claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0051653 | Apr 2022 | KR | national |
