Patent Application
20220308449
The present invention relates to a treatment liquid for patterning a resist film and a pattern forming method.
More specifically, the present invention relates to a treatment liquid and a pattern forming method which are used for a step of manufacturing a semiconductor such as an integrated circuit (IC), a step of manufacturing a circuit board for a liquid crystal or a thermal head, and a lithography step for photofabrication.
In processes for manufacturing semiconductor devices such as integrated circuits (IC) and large scale integrated circuits (LSI) in the related art, microfabrication by lithography using a photoresist composition has been performed. In recent years, with the high integration of integrated circuits, the formation of ultrafine patterns in a submicron region or quarter micron region has been required. With such a demand, a tendency that an exposure wavelength has been shifted from g-rays to i-rays, and further, as with KrF excimer laser light, the exposure wavelength is shortened is observed. Moreover, development of lithography with electron beams, X-rays, or extreme ultraviolet rays (EUV), in addition to the excimer laser light, has also been currently in progress.
In such lithography, a film (resist film) is formed by an actinic ray-sensitive or radiation-sensitive composition (also referred to as a resist composition), and the obtained film is subjected to a treatment of being developed with a developer and the developed film is subjected to a treatment of being washed with a rinsing liquid.
For example, JP2013-045086A discloses that 1-hexanol is used as a rinsing liquid after development with butyl acetate.
In recent years, with high integration of integrated circuits, formation of fine patterns (high-resolution patterns) using resist compositions has been required. In the formation of such fine patterns, there is a problem in that a large capillary force is generated due to a decrease in the distance between patterns as a result of the miniaturization, and thus high-quality patterns are unlikely to be formed.
Further, since the film thickness of a pattern tends to be decreased with the miniaturization, resolution of performance degradation of the pattern due to “reduction in film thickness of the pattern” during the development treatment and the rinsing treatment is significantly required more than before. That is, there is a demand for a treatment liquid (developer and/or rinsing liquid) that can simultaneously resolve the occurrence of pattern collapse and reduction in film thickness of a pattern.
It is also required to suppress residues on the obtained pattern in a case where the treatment liquid is applied.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a treatment liquid excellent in resolution, a property of suppressing reduction in film thickness, and a property of suppressing residues, in a case of being used for at least one of developing or washing (rinsing) a resist film. Further, another object of the present invention is to provide a pattern forming method for the above-described treatment liquid.
As a result of intensive examination conducted by the present inventors in order to solve the above-described problems, it was found that the above-described objects can be achieved by the following configuration, thereby completing the present invention.
[1] A treatment liquid for patterning a resist film, which is used for performing at least one of development or washing after exposure on a resist film obtained from an actinic ray-sensitive or radiation-sensitive composition, the treatment liquid comprising: a first organic solvent that satisfies Condition A; and a second organic solvent that satisfies Condition B,
Condition A: the solvent has a SP value of 15.0 MPa1/2 or greater and less than 16.5 MPa1/2 which is acquired by Equation (1) and is a hydrocarbon-based solvent, an ester-based solvent, an ether-based solvent, or a carbonic acid ester-based solvent,
SP value=((δd)2+(δp)2+(δh)2)0.5 Equation (1):
SP value: Hansen solubility parameter of organic solvent
δd: dispersion element of organic solvent
δp: polarity element of organic solvent
δh: hydrogen bond element of organic solvent
Condition B: the solvent has a SP value of 16.5 MPa1/2 or greater and less than 17.6 MPa1/2 which is acquired by Equation (1) and has an X value of 7.0 or greater and less than 20.0 which is acquired by Equation (2), and is a hydrocarbon-based solvent, an ester-based solvent, an ether-based solvent, or a carbonic acid ester-based solvent,
X=(δp)2/((δd)2+(δp)2+(δh)2)×100. Equation (2):
[2] The treatment liquid according to [1], in which the first organic solvent is an ether-based solvent having 6 to 12 carbon atoms.
[3] The treatment liquid according to [1] or [2], in which the second organic solvent is an ester-based solvent having 5 to 8 carbon atoms or a carbonic acid ester-based solvent having 5 to 9 carbon atoms.
[4] The treatment liquid according to any one of [1] to [3], in which the first organic solvent is an ether-based solvent having 6 to 12 carbon atoms, which contains a branched chain alkyl group.
[5] The treatment liquid according to any one of [1] to [4], in which the second organic solvent is an ester-based solvent having 5 to 8 carbon atoms, which contains a branched chain alkyl group.
[6] The treatment liquid according to any one of [1] to [5], in which the first organic solvent is selected from the group consisting of diisopropyl ether, diisobutyl ether, diisoamyl ether, isopropyl propyl ether, isopropyl n-butyl ether, n-propyl isobutyl ether, isopropyl isobutyl ether, isopropyl isoamyl ether, isobutyl isoamyl ether, n-butyl isoamyl ether, and n-amyl isoamyl ether.
[7] The treatment liquid according to any one of [1] to [6], in which the second organic solvent is selected from the group consisting of t-butyl formate, isopentyl formate, 1,1-dimethylpropyl formate, 2,2-dimethylpropyl formate, 2-methylbutyl formate, isopropyl propanoate, isopentyl propanoate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, diisobutyl carbonate, ditert-butyl carbonate, and ethyl isopentyl carbonate.
[8] The treatment liquid according to any one of [1] to [7], in which the first organic solvent and the second organic solvent satisfy a relationship of Expression (3),
5.0° C.<bp1−bp2<100.0° C. Expression (3):
bp1: boiling point of first organic solvent
bp2: boiling point of second organic solvent.
[9] The treatment liquid according to any one of [1] to [8], in which the actinic ray-sensitive or radiation-sensitive composition contains a resin having a hydroxystyrene-based repeating unit.
[10] A pattern forming method comprising: a resist film forming step of forming a resist film by using an actinic ray-sensitive or radiation-sensitive composition; an exposing step of exposing the resist film; and a treatment step of treating the exposed resist film with the treatment liquid according to any one of [1] to [8].
[11] A pattern forming method comprising: a resist film forming step of forming a resist film by using an actinic ray-sensitive or radiation-sensitive composition; an exposing step of exposing the resist film; and a treatment step of treating the exposed resist film, in which the treatment step includes a developing step of developing the film with a developer, and a rinsing step of washing the film with a rinsing liquid, and the rinsing liquid is the treatment liquid according to any one of [1] to [8].
According to the present invention, it is possible to provide a treatment liquid excellent in resolution, a property of suppressing reduction in film thickness, and a property of suppressing residues, in a case of being used for at least one of developing or washing (rinsing) a resist film. Further, it is possible to provide a pattern forming method for the above-described treatment liquid.
Hereinafter, the present invention will be described in detail.
In notations for a group (atomic group) in the present specification, in a case where the group is cited without specifying whether it is substituted or unsubstituted, the group includes both a group having no substituent and a group having a substituent as long as this does not impair the spirit of the present invention. For example, “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group), but also an alkyl group having a substituent (substituted alkyl group). In addition, “organic group” in the present specification denotes a group having at least one carbon atom.
“Actinic rays” or “radiation” in the present specification denotes, for example, a bright line spectrum of a mercury lamp, far ultraviolet rays typified by an excimer laser, extreme ultraviolet rays (EUV light), X-rays, or electron beams (EB). In the present specification, “light” denotes actinic rays or radiation.
In the present specification, the concept of “exposure” includes not only exposure to a bright line spectrum of a mercury lamp, far ultraviolet rays typified by an excimer laser, extreme ultraviolet rays (EUV light), X-rays, and the like, but also lithography by particle beams such as electron beams and ion beams, unless otherwise specified.
In the present specification, a numerical range shown using “to” indicates a range including numerical values described before and after “to” as a lower limit and an upper limit.
The bonding direction of divalent groups denoted in the present specification is not limited unless otherwise specified.
In the present specification, (meth)acrylate denotes acrylate and methacrylate, and (meth)acryl denotes acryl and methacryl.
In the present specification, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
In the present specification, the weight-average molecular weight (Mw), the number average molecular weight (Mn), and the dispersity (also referred to as molecular weight distribution) (Mw/Mn) of a resin are defined as values in terms of polystyrene by means of gel permeation chromatography (GPC) measurement (solvent: tetrahydrofuran, flow rate (amount of sample to be injected): 10 μL, columns: TSK gel Multipore HXL-M, manufactured by Tosoh Corporation, column temperature: 40° C., flow speed: 1.0 mL/min, detector: differential refractive index detector) using a GPC device (HLC-8120 GPC, manufactured by Tosoh Corporation).
The Hansen solubility parameter (also referred to as “SP value”, unit: MPa1/2) in the present specification is defined by three-dimensional parameters (δd, δp, and δh) and is acquired by Equation (1). The details of the SP value are described in “PROPERTIES OF POLYMERS” (writer: D. W. VAN KREVELEN, publisher: ELSEVIER SCIENTIFIC PUBLISHING COMPANY, published in 1989, 5th edition).
SP value=((δd)2+(δp)2+(δh)2)0.5 Equation (1):
In the present specification, the boiling point denotes a boiling point at 1 atm.
In the present specification, the organic solvent denotes an organic compound in a liquid state at 25° C.
[Treatment Liquid]
In a case where a pattern is formed by exposing and developing a resist film, residues may be generated on the pattern. In order to suppress generation of residues and/or reduce residues on such a pattern, an organic solvent with a high polarity can be effectively used as a treatment liquid (developer and/or rinsing liquid). However, the organic solvent with a high polarity may dissolve the pattern itself and cause reduction in film thickness of the pattern. In addition, such an organic solvent with a high polarity alone is likely to have low volatility and may be a factor of deteriorating the resolution of a dense pattern (for example, causing pattern collapse of a dense pattern).
The present inventors consider that the use of the treatment liquid of the present invention is particularly significant in a case where the pattern is formed by exposure to EUV light.
Further, in the treatment liquid, it is also preferable that an organic solvent having volatility higher than that of the first organic solvent is selected as the second organic solvent, and for example, it is preferable that the first organic solvent and the second organic solvent satisfy the relationship of Expression (3).
Hereinafter, first, the first organic solvent and the second organic solvent will be described.
[First Organic Solvent]
SP value=((δd)2+(δp)2+(δh)2)0.5 Equation (1):
The SP value of the first organic solvent is 15.0 MPa1/2 or greater and less than 16.5 MPa1/2, preferably greater than 15.0 MPa1/2 and less than 16.5 MPa1/2, more preferably 15.2 MPa1/2 or greater and less than 16.5 MPa1/2, and still more preferably 15.4 MPa1/2 or greater and less than 16.5 MPa1/2.
The first organic solvent may be any of a hydrocarbon-based solvent, an ester-based solvent, an ether-based solvent, or a carbonic acid ester-based solvent.
Examples of the hydrocarbon-based solvent that can be used as the first organic solvent include decane.
In a case where the first organic solvent is an ether-based solvent, the number of carbon atoms of the ether-based solvent is preferably in a range of 6 to 12 and more preferably in a range of 8 to 10.
As the ether-based solvent that can be used as the first organic solvent, one or more organic solvents selected from the group consisting of diisopropyl ether, diisobutyl ether, diisoamyl ether, isopropyl propyl ether, isopropyl n-butyl ether, n-propyl isobutyl ether, isopropyl isobutyl ether, isopropyl isoamyl ether, isobutyl isoamyl ether, n-butyl isoamyl ether, n-amyl isoamyl ether, and dibutyl ether are preferable, and one or more organic solvents selected from the group consisting of diisopropyl ether, diisobutyl ether, diisoamyl ether, isopropyl propyl ether, isopropyl n-butyl ether, n-propyl isobutyl ether, isopropyl isobutyl ether, isopropyl isoamyl ether, isobutyl isoamyl ether, n-butyl isoamyl ether, and n-amyl isoamyl ether are more preferable.
It is also preferable that an ester-based solvent is used as the first organic solvent.
As the ester-based solvent that can be used as the first organic solvent, isobutyl isobutanoate is preferable.
The first organic solvent may be used alone or in combination of two or more kinds thereof.
The content of the first organic solvent is preferably in a range of 1% to 90% by mass, more preferably in a range of 3% to 75% by mass, and still more preferably in a range of 5% to 60% by mass with respect to the total mass of the treatment liquid.
[Second organic solvent]
The SP value of the second organic solvent is 16.5 MPa1/2 or greater and less than 17.6 MPa1/2, preferably greater than 16.5 MPa1/2 and less than 17.6 MPa1/2, more preferably 16.7 MPa1/2 or greater and less than 17.6 MPa1/2, and still more preferably 16.8 MPa1/2 or greater and less than 17.6 MPa1/2.
In the second organic solvent, the X value acquired by Equation (2) is 7.0 or greater and less than 20.0, preferably in a range of 7.0 to 19.0, more preferably in a range of 7.0 to 16.0, and still more preferably greater than 7.0 and 14.0 or less.
X=(δp)2/((δd)2+(δp)2+(δh)2)×100. Equation (2):
The second organic solvent contains preferably a linear or branched chain alkyl group and more preferably a branched chain alkyl group.
The second organic solvent may be any of a hydrocarbon-based solvent, an ester-based solvent, an ether-based solvent, or a carbonic acid ester-based solvent.
In a case where the second organic solvent is an ester-based solvent, the number of carbon atoms of the ester-based solvent is more preferably in a range of 5 to 8.
As the ester-based solvent that can be used as the second organic solvent, one or more organic solvents selected from the group consisting of t-butyl formate, isopentyl formate, 1,1-dimethylpropyl formate, 2,2-dimethylpropyl formate, 2-methylbutyl formate, isopropyl propanoate, isopentyl propanoate, and propyl propionate are preferable, and one or more organic solvents selected from the group consisting of t-butyl formate, isopentyl formate, 1,1-dimethylpropyl formate, 2,2-dimethylpropyl formate, 2-methylbutyl formate, isopropyl propanoate, and isopentyl propanoate are more preferable.
In a case where the second organic solvent is a carbonic acid ester-based solvent, the number of carbon atoms of the carbonic acid ester-based solvent is preferably in a range of 5 to 9.
As the carbonic acid ester-based solvent that can be used as the second organic solvent, one or more organic solvents selected from the group consisting of diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, diisobutyl carbonate, ditert-butyl carbonate, and ethyl isopentyl carbonate are preferable.
The second organic solvent may be used alone or in combination of two or more kinds thereof.
Further, the treatment liquid may intentionally or inevitably contain a regioisomer (for example, a regioisomer of the first or second organic solvent containing a linear or branched chain alkyl group) of the organic solvent in addition to the first or second organic solvent to be contained in the treatment liquid. The regioisomer may correspond to the first or second organic solvent or may correspond to another component.
The content of the second organic solvent is preferably in a range of 10% to 99% by mass, more preferably in a range of 25% to 97% by mass, and still more preferably in a range of 40% to 95% by mass with respect to the total mass of the treatment liquid.
[Relationship Between First Organic Solvent and Second Organic Solvent]
5.0° C.<bp1−bp2<100.0° C. Expression (3):
0.0° C.<bp1−bp2<120.0° C. Expression (4):
−50.0° C.<bp1−bp2<150.0° C. Expression (5):
It is preferable that at least one of the first organic solvent or the second organic solvent of the treatment liquid according to the embodiment of the present invention contains a branched chain alkyl group.
The treatment liquid according to the embodiment of the present invention may contain at least one first organic solvent and at least one second organic solvent.
[Other Components]
<Metal Component>
Examples of the metal atom contained in the metal component include metal atoms selected from the group consisting of Ag, Al, As, Au, Ba, Ca, Cd, Co, Cr, Cu, Fe, Ga, Ge, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sn, Sr, Ti, and Zn.
In a case where the treatment liquid contains a metal component, the content of the metal component is preferably greater than 0 mass ppt and 1 mass ppm or less, more preferably greater than 0 mass ppt and 10 mass ppb or less, and still more preferably greater than 0 mass ppt and 10 mass ppt or less with respect to the total mass of the treatment liquid.
<Ionic Liquid>
Examples of commercially available products of the ionic liquid include IL-P14 and IL-A2 (both manufactured by Koei Chemical Industry Co., Ltd.) and ELEGAN SS-100 (manufactured by NOF Corporation) which is a quaternary ammonium salt-based ionic liquid. The ionic liquid may be used alone or in combination of two or more kinds thereof.
In a case where the treatment liquid according to the embodiment of the present invention contains an ionic liquid, the content of the ionic liquid is preferably in a range of 0.5% to 15% by mass, more preferably in a range of 1% to 10% by mass, and still more preferably in a range of 1% to 5% by mass with respect to the total mass of the treatment liquid.
<Surfactant>
<Antioxidant>
<Basic Compound>
<Other Solvents>
<Organic Substance Having Boiling Point of 300° C. or Higher>
From the viewpoint of suppressing the organic substance from remaining on the surface of the substrate without being volatilized and from causing defect failure in a case where the treatment liquid is used as a developer and brought into contact with the substrate, it is preferable that the content of the organic substance having a boiling point of 300° C. or higher is 30 mass ppm or less with respect to the total mass of the treatment liquid.
Examples of a method of setting the content of organic substance having a boiling point of 300° C. or higher in the treatment liquid to be in the above-described range include the methods described in the section of the purifying step below.
[Pattern Forming Method]
Hereinafter, each step of the pattern forming method will be described. Further, a developing step and a rinsing step will be respectively described as an example of the treatment step.
<Resist Film Forming Step (i)>
For example, a support (substrate) is coated with the resist composition by an appropriate coating method such as a spinner. Thereafter, the coating film (the coating film of the applied resist composition) is dried to form a resist film. Various undercoat films (an inorganic film, an organic film, an antireflection film, and the like) may be formed on the underlayer of the resist film as necessary.
The support forming the resist film is not particularly limited, and a substrate which is typically used in a step of manufacturing a semiconductor such as an IC, a step of manufacturing a circuit board for a liquid crystal, a thermal head, or the like, and other lithographic steps of photofabrication can be used.
As the drying method, a method of drying the composition by heating the composition is typically used.
The film thickness of the resist film is typically 200 nm or less and preferably 100 nm or less.
<Exposing Step (ii)>
In the pattern forming method, the film forming step (i), the exposing step (ii), and the developing step (iii) described above can be performed by a generally known method.
For any of the prebake step (iv) or the post-exposure bake step (v), the heating temperature is preferably in a range of 80° C. to 150° C., more preferably in a range of 80° C. to 140° C., and still more preferably in a range of 80° C. to 130° C.
A light source wavelength used in the exposing step is not limited, and examples thereof include infrared light, visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), an X-ray, and an electron beam. Among these, far ultraviolet light is preferable, and the wavelength thereof is preferably 250 nm or less, more preferably 220 nm or less, and still more preferably in a range of 1 to 200 nm. Specific examples thereof include a KrF excimer laser (248 nm), an ArF excimer laser (193 nm), an F2 excimer laser (157 nm), an X-ray, EUV (13 nm), and an electron beam. Among these, a KrF excimer laser, an ArF excimer laser, EUV, or an electron beam is preferable, and EUV or an electron beam is more preferable.
<Step (iii) of Treating Exposed Film>
(Developing Step)
Examples of the developing method include a method in which a substrate is immersed in a tank filled with a developer for a certain period of time (dip method), a method in which development is performed by heaping a developer up onto a surface of a substrate by surface tension and allowing the developer to stand for a certain period of time (puddle method), a method in which a developer is sprayed onto a surface of a substrate (spray method), and a method in which a developer is continuously jetted onto a substrate rotating at a constant rate while a developer jetting nozzle is scanned at a constant rate (dynamic dispense method).
As the developer, the above-described treatment liquid may be used or another developer may be used.
Other Developers
It is preferable that the developer contains one or more solvents selected from the group consisting of a ketone-based solvent, an ester-based solvent, an alcohol-based solvent, and an ether-based solvent.
Examples of the ester-based solvent include methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, isopropyl acetate, amyl acetate (pentyl acetate), isoamyl acetate (isopentyl acetate), 3-methylbutyl acetate, 2-methylbutyl acetate, 1-methylbutyl acetate, hexyl acetate, isohexyl acetate, heptyl acetate, octyl acetate, ethyl methoxyacetate, ethyl ethoxyacetate, propylene glycol monomethyl ether acetate (PGMEA; also known as 1-methoxy-2-acetoxypropane), ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, 4-methyl-4-methoxypentyl acetate, propylene glycol diacetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, butyl propionate, pentyl propionate, hexyl propionate, heptyl propionate, butyl butanoate, isobutyl butanoate, pentyl butanoate, hexyl butanoate, isobutyl isobutanoate, propyl pentanoate, isopropyl pentanoate, butyl pentanoate, pentyl pentanoate, ethyl hexanoate, propyl hexanoate, butyl hexanoate, isobutyl hexanoate, methyl heptanoate, ethyl heptanoate, propyl heptanoate, cyclohexyl acetate, cycloheptyl acetate, 2-ethylhexyl acetate, cyclopentyl propionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, and propyl-3-methoxypropionate.
Examples of the ketone-based solvent include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone, 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, cyclohexanone, methylcyclohexanone, phenyl acetone, methyl ethyl ketone, methyl isobutyl ketone, acetyl acetone, acetonyl acetone, ionone, diacetonyl alcohol, acetyl carbinol, acetophenone, methyl naphthyl ketone, isophorone, propylene carbonate, and γ-butyrolactone. Among these, 2-heptanone is preferable.
Examples of the alcohol-based solvent include alcohol (monohydric alcohol) such as methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, 3-methyl-1-butanol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-decanol, 2-hexanol, 2-heptanol, 2-octanol, 3-hexanol, 3-heptanol, 3-octanol, 4-octanol, 3-methyl-3-pentanol, cyclopentanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-2-butanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 5-methyl-2-hexanol, 4-methyl-2-hexanol, 4,5-dimethyl-2-hexanol, 6-methyl-2-heptanol, 7-methyl-2-octanol, 8-methyl-2-nonanol, 9-methyl-2-decanol, or 3-methoxy-1-butanol; a glycol-based solvent such as ethylene glycol, diethylene glycol, or triethylene glycol; and a glycol ether-based solvent containing a hydroxyl group, such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether (PGME; also known as 1-methoxy-2-propanol), diethylene glycol monomethyl ether, triethylene glycol monoethyl ether, methoxymethylbutanol, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, or propylene glycol monophenyl ether. Among these, a glycol ether-based solvent is preferable.
Examples of the ether-based solvent include a glycol ether-based solvent containing no hydroxyl group, such as propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, or diethylene glycol diethyl ether; an aromatic ether solvent such as anisole or phenetol; dioxane, tetrahydrofuran, tetrahydropyran, perfluoro-2-butyl tetrahydrofuran, perfluorotetrahydrofuran, 1,4-dioxane, and isopropyl ether, in addition to the above-described glycol ether-based solvent containing a hydroxyl group. Among these, a glycol ether-based solvent or an aromatic ether-based solvent such as anisole is preferable.
Examples of the amide-based solvent include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, hexamethylphosphoric triamide, and 1,3-dimethyl-2-imidazolidinone.
Examples of the hydrocarbon-based solvent include an aliphatic hydrocarbon-based solvent such as pentane, hexane, octane, nonane, decane, dodecane, undecane, hexadecane, 2,2,4-trimethylpentane, 2,2,3-trimethylhexane, perfluorohexane, or perfluoroheptane; and an aromatic hydrocarbon-based solvent such as toluene, xylene, ethylbenzene, propylbenzene, 1-methylpropylbenzene, 2-methylpropylbenzene, dimethylbenzene, diethylbenzene, ethylmethylbenzene, trimethylbenzene, ethyldimethylbenzene, or dipropylbenzene.
From the viewpoint of suppressing swelling of the resist film in a case where EUV light and electron beams are used in the exposing step, an ester-based solvent having 6 or more carbon atoms (preferably 6 to 14 carbon atoms, more preferably 6 to 12 carbon atoms, and still more preferably 6 to 10 carbon atoms), and 2 or less heteroatoms is preferable as the developer.
From the viewpoint of further suppressing swelling of the resist film in a case where EUV light and electron beams are used in the exposing step, a mixed solvent of an ester-based solvent and a hydrocarbon-based solvent or a mixed solvent of a ketone-based solvent and a hydrocarbon-based solvent may be used as the developer, in place of the ester-based solvent having 6 or more carbon atoms and 2 or less heteroatoms.
The content of the hydrocarbon-based solvent in the mixed solvent is not particularly limited because the content thereof depends on the solvent solubility of the resist film, the required amount may be determined by appropriately adjusting the content.
In the mixed solvent of an ester-based solvent and a hydrocarbon-based solvent, isoamyl acetate is preferable as the ester-based solvent. From the viewpoint of easily adjusting the solubility of the resist film, a saturated hydrocarbon-based solvent (for example, octane, nonane, decane, dodecane, undecane, or hexadecane) is preferable as the hydrocarbon-based solvent.
Examples of the ketone-based solvent in the mixed solvent of a ketone-based solvent and a hydrocarbon-based solvent include 1-octanone, 2-octanone, 1-nonanone, 2-nonanone, acetone, 2-heptanone (methyl amyl ketone), 4-heptanone, 1-hexanone, 2-hexanone, diisobutyl ketone, 2,5-dimethyl-4-hexanone, cyclohexanone, methylcyclohexanone, phenyl acetone, methyl ethyl ketone, methyl isobutyl ketone, acetyl acetone, acetonyl acetone, ionone, diacetonyl alcohol, acetyl carbinol, acetophenone, methyl naphthyl ketone, isophorone, and propylene carbonate. Among these, diisobutyl ketone or 2,5-dimethyl-4-hexanone is preferable. From the viewpoint of easily adjusting the solubility of the resist film, a saturated hydrocarbon-based solvent (for example, octane, nonane, decane, dodecane, undecane, or hexadecane) is preferable as the hydrocarbon-based solvent.
The solvent may be used in a mixture of a plurality of the above-described solvents or in a mixture with water or a solvent other than those described above. The moisture content in the entire developer is preferably less than 50% by mass, more preferably less than 20% by mass, still more preferably less than 10% by mass, and particularly preferably substantially zero.
The developer may include an appropriate amount of a known surfactant as necessary.
The content of the surfactant is typically in a range of 0.001% to 5% by mass, preferably in a range of 0.005% to 2% by mass, and more preferably in a range of 0.01% to 0.5% by mass with respect to the total amount of the developer.
The developer may include a basic compound. Specific examples of the basic compound include compounds exemplified as an acid diffusion control agent that can be contained in the resist composition described below.
As the organic solvent used as a developer, an ester-based solvent represented by General Formula (S1) or General Formula (S2) is also preferable in addition to the above-described ester-based solvents.
As the ester-based solvent, an ester-based solvent represented by General Formula (S1) is more preferable, alkyl acetate is still more preferable, and butyl acetate, amyl acetate (pentyl acetate), or isoamyl acetate (isopentyl acetate) is particularly preferable.
R—C(═O)—O—R′ General Formula (S1)
In General Formula (S1), R and R′ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl group, an alkoxycarbonyl group, a carboxyl group, a hydroxyl group, a cyano group, or a halogen atom. R and R′ may be bonded to each other to form a ring.
Examples of the solvent represented by General Formula (S1) include methyl acetate, butyl acetate, ethyl acetate, isopropyl acetate, amyl acetate, isoamyl acetate, methyl formate, ethyl formate, butyl formate, propyl formate, ethyl lactate, butyl lactate, propyl lactate, ethyl carbonate, propyl carbonate, butyl carbonate, methyl pyruvate, ethyl pyruvate, propyl pyruvate, butyl pyruvate, methyl acetoacetate, ethyl acetoacetate, methyl propionate, ethyl propionate, propyl propionate, isopropyl propionate, methyl 2-hydroxypropionate, and ethyl 2-hydroxypropionate.
Among these, it is preferable that R and R′ represent an unsubstituted alkyl group.
In a case where the developer contains a solvent represented by General Formula (S1), the developer may further contain one or more other organic solvents (hereinafter, also referred to as “combined solvent”). The combined solvent is not particularly limited as long as the combined solvent can be mixed with a solvent represented by General Formula (S1) without being separated, and examples thereof include a solvent selected from the group consisting of an ester-based solvent, a ketone-based solvent, an alcohol-based solvent, an amide-based solvent, an ether-based solvent, and a hydrocarbon-based solvent other than the solvent represented by General Formula (S1).
As the organic solvent used as a developer, a solvent represented by General Formula (S2) is also preferable.
R″—C(═O)—O—R′″—O—R″ General Formula (S2)
In General Formula (S2), R″ and R″″ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl group, an alkoxycarbonyl group, a carboxyl group, a hydroxyl group, a cyano group, or a halogen atom. R″ and R′″ may be bonded to each other to form a ring.
Examples of the solvent represented by General Formula (S2) include propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether acetate, ethylene glycol monobutyl ether acetate, ethylene glycol monophenyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monopropyl ether acetate, diethylene glycol monophenyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methyl-3-methoxypropionate, ethyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propyl-3-methoxypropionate, ethyl methoxyacetate, ethyl ethoxyacetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxybutyl acetate, 2-ethoxybutyl acetate, 4-ethoxybutyl acetate, 4-propoxybutyl acetate, 2-methoxypentyl acetate, 3-methoxypentyl acetate, 4-methoxypentyl acetate, 2-methyl-3-methoxypentyl acetate, 3-methyl-3-methoxypentyl acetate, 3-methyl-4-methoxypentyl acetate, and 4-methyl-4-methoxypentyl acetate. Among these, propylene glycol monomethyl ether acetate is preferable.
In a case where the developer contains a solvent represented by General Formula (S2), the developer may further contain one or more other organic solvents (hereinafter, also referred to as “combined solvent”). The combined solvent is not particularly limited as long as the combined solvent can be mixed with a solvent represented by General Formula (S2) without being separated, and examples thereof include a solvent selected from the group consisting of an ester-based solvent, a ketone-based solvent, an alcohol-based solvent, an amide-based solvent, an ether-based solvent, and a hydrocarbon-based solvent other than the solvent represented by General Formula (S2).
Further, as the organic solvent used as a developer, an ether-based solvent containing one or more aromatic rings is also preferable, a solvent represented by General Formula (S3) is more preferable, and anisole is still more preferable.
In General Formula (S3), RS represents an alkyl group. As the alkyl group, an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group or an ethyl group is more preferable, and a methyl group is still more preferable.
An aqueous alkali developer may be used as the developer (other developers).
(Rinsing Step)
In the rinsing step, the substrate which has been subjected to development is subjected to a washing treatment using the above-described rinsing liquid.
As the rinsing liquid, the above-described treatment liquid may be used or other rinsing liquids may be used.
In addition, a treatment of removing the developer or the rinsing liquid adhering onto a pattern with a supercritical fluid can be performed after the development treatment or the rinsing treatment.
In the pattern forming method according to the embodiment of the present invention, the treatment liquid according to the embodiment of the present invention is used as at least one of the developer or the rinsing liquid. Among these, it is preferable that the treatment liquid according to the embodiment of the present invention is used as the rinsing liquid.
For example, in a case where pattern formation is performed using an ester-based solvent as the developer in the developing step and using the treatment liquid according to the embodiment of the present invention as the rinsing liquid in the rinsing step, it is preferable that the supply interval of the developer and the rinsing liquid to the resist film after exposure is set to 1 second or longer. By setting the supply interval of the developer and the rinsing liquid to a predetermined time or longer, deterioration of the solubility of the unexposed region of the resist film after exposure can be suppressed, and an increase of defects due to the solvent shock can be suppressed.
Further, the developer and the rinsing liquid are typically accommodated in a common waste liquid tank through a pipe after use. Here, in a case where an ester-based solvent is used as the developer in the developing step and the treatment liquid according to the embodiment of the present invention is used as the rinsing liquid in the rinsing step, there is a concern that the resist dissolved in the developer is deposited and adhered to the rear surface of the substrate and the side surface of the pipe so that the device is contaminated.
Examples of other methods for solving the above-described problem include a method of adjusting the amount ratio between the developer and the rinsing liquid flowing into the pipe after use to an amount ratio set such that deposition of the resist does not occur and a method of further mixing a solvent having a high solubility for the resist with the developer and the rinsing liquid flowing through the pipe after use, in order to prevent deposition of the resist in the waste liquid flowing into the waste liquid tank through the pipe after use. Specific examples of the method include a method of suppressing deposition and precipitation of the resist in the waste liquid flowing into the waste liquid tank through the pipe after use by continuously supplying an organic solvent having a SP value higher than that of the first organic solvent and/or the second organic solvent contained in the treatment liquid according to the embodiment of the present invention to the rear surface of the wafer, between the developing step and the rinsing step.
Further, it is also preferable that the developer and the rinsing liquid are accommodated in separate waste liquid tanks after use.
[Resist Composition]
<Resin (A)>
<<Repeating Unit Containing Acid-Decomposable Group>>
Examples of the leaving group that leaves due to the action of an acid include groups represented by Formulae (Y1) to (Y4).
—C(Rx1)(Rx2)(Rx3) Formula (Y1):
—C(═O)OC(Rx1)(Rx2)(Rx3) Formula (Y2):
—C(R36)(R37)(OR38) Formula (Y3):
—C(Rn)(H)(Ar) Formula (Y4):
In Formula (Y1) and Formula (Y2), Rx1 to Rx3 each independently represent a (linear or branched chain) alkyl group or (monocyclic or polycyclic) cycloalkyl group, a (linear or branched chain) alkenyl group, or a (monocyclic or polycyclic) aryl group. In addition, in a case where all of Rx1 to Rx3 represent a (linear or branched chain) alkyl group, it is preferable that at least two of Rx1, Rx2, or Rx3 represent a methyl group.
In Formula (Y3), R36 to R38 each independently represent a hydrogen atom or a monovalent organic group. R37 and R38 may be bonded to each other to form a ring. Examples of the monovalent organic group include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group. It is also preferable that R36 represents the hydrogen atom.
As Formula (Y3), a group represented by Formula (Y3-1) is preferable.
Here, L1 and L2 each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a group formed by combination thereof (for example, a group formed by combination of an alkyl group and an aryl group).
In Formula (Y4), Ar represents an aromatic ring group. Rn represents an alkyl group, a cycloalkyl group, or an aryl group. Rn and Ar may be bonded to each other to form a non-aromatic ring. Ar is more preferably an aryl group.
From the viewpoint that the acid decomposability of the repeating unit is excellent, in a case where a non-aromatic ring is directly bonded to a polar group (or a residue thereof) in an leaving group that protects the polar group, it is also preferable that a ring member atom adjacent to the ring member atom directly bonded to the polar group (or a residue thereof) in the non-aromatic ring has no halogen atom such as a fluorine atom as a substituent.
In addition, the leaving group that leaves due to the action of an acid may be a 2-cyclopentenyl group having a substituent (an alkyl group and the like), such as a 3-methyl-2-cyclopentenyl group, and a cyclohexyl group having a substituent (an alkyl group and the like), such as 1,1,4,4-tetramethylcyclohexyl group.
As the repeating unit having an acid-decomposable group, a repeating unit represented by Formula (A) is also preferable.
L1 represents a divalent linking group which may have a fluorine atom or an iodine atom, R1 represents a hydrogen atom, a fluorine atom, an iodine atom, a fluorine atom, an alkyl group which may have an iodine atom, or an aryl group which may have a fluorine atom or an iodine atom, and R2 represents an leaving group that leaves due to the action of an acid and may have a fluorine atom or an iodine atom. Here, at least one of L1, R1, or R2 has a fluorine atom or an iodine atom.
R1 represents a hydrogen atom, a fluorine atom, an iodine atom, an alkyl group which may have a fluorine atom or an iodine atom, or an aryl group which may have a fluorine atom or an iodine atom.
R2 represents a leaving group that leaves due to the action of an acid and may have a fluorine atom or an iodine atom.
—C(Rx11)(Rx12)(Rx13). Formula (Z1):
—C(═O)OC(Rx11)(Rx12)(Rx13). Formula (Z2):
—C(R136)(R137)(OR138). Formula (Z3):
—C(Rn1)(H)(Ar1) Formula (Z4):
In Formulae (Z1) and (Z2), Rx11 to Rx13 each independently represent an (linear or branched) alkyl group which may have a fluorine atom or an iodine atom, a (monocyclic or polycyclic) cycloalkyl group which may have a fluorine atom or an iodine atom, an (linear or branched chain) alkenyl group which may have a fluorine atom or an iodine atom, or an (monocyclic or polycyclic) aryl group which may have a fluorine atom or an iodine atom. In addition, in a case where all of Rx11 to Rx13 are (linear or branched chain) alkyl groups, it is preferable that at least two of Rx11, . . . , or Rx13 are methyl groups.
In Formula (Z3), R136 to R138 each independently represent a hydrogen atom, or a monovalent organic group which may have a fluorine atom or an iodine atom. R137 and R138 may be bonded to each other to form a ring. Examples of the monovalent organic group which may have a fluorine atom or an iodine atom include an alkyl group which may have a fluorine atom or an iodine atom, a cycloalkyl group which may have a fluorine atom or an iodine atom, an aryl group which may have a fluorine atom or an iodine atom, an aralkyl group which may have a fluorine atom or an iodine atom, and a group formed by combination thereof (for example, a group formed by combination of an alkyl group and a cycloalkyl group).
As Formula (Z3), a group represented by Formula (Z3-1) is preferable.
Here, L11 and L12 each independently represent a hydrogen atom; an alkyl group which may have a heteroatom selected from the group consisting of a fluorine atom, an iodine atom, and an oxygen atom; a cycloalkyl group which may have a heteroatom selected from the group consisting of a fluorine atom, an iodine atom, and an oxygen atom; an aryl group which may have a heteroatom selected from the group consisting of a fluorine atom, an iodine atom, and an oxygen atom; or a group formed by combination thereof (for example, a group formed by combination of an alkyl group and a cycloalkyl group, each of which may have a heteroatom selected from the group consisting of a fluorine atom, an iodine atom, and an oxygen atom).
In Formula (Z4), Ar1 represents an aromatic ring group which may have a fluorine atom or an iodine atom. Rn1 represents an alkyl group which may have a fluorine atom or an iodine atom, a cycloalkyl group which may have a fluorine atom or an iodine atom, or an aryl group which may have a fluorine atom or an iodine atom. Rn1 and Ar1 may be bonded to each other to form a non-aromatic ring.
As the repeating unit having an acid-decomposable group, a repeating unit represented by General Formula (AI) is also preferable.
In General Formula (AI), Xa1 represents a hydrogen atom, or an alkyl group which may have a substituent.
Examples of the alkyl group which may have a substituent, represented by Xa1, include a methyl group and a group represented by —CH2-R11. R11 represents a halogen atom (a fluorine atom or the like), a hydroxyl group, or a monovalent organic group, examples thereof include an alkyl group having 5 or less carbon atoms, which may be substituted with a halogen atom, an acyl group having 5 or less carbon atoms, which may be substituted with a halogen atom, and an alkoxy group having 5 or less carbon atoms, which may be substituted with a halogen atom; and an alkyl group having 3 or less carbon atoms is preferable, and a methyl group is more preferable. Xa1 is preferably a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.
Examples of the divalent linking group of T include an alkylene group, an aromatic ring group, a —COO-Rt- group, and an —O-Rt- group. In the formulae, Rt represents an alkylene group or a cycloalkylene group.
As the alkyl group as Rx1 to Rx3, an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a t-butyl group, is preferable.
In a case where each of the groups has a substituent, examples of the substituent include an alkyl group (having 1 to 4 carbon atoms), a halogen atom, a hydroxyl group, an alkoxy group (having 1 to 4 carbon atoms), a carboxyl group, and an alkoxycarbonyl group (having 2 to 6 carbon atoms). The substituent preferably has 8 or less carbon atoms.
The repeating unit represented by General Formula (AI) is preferably an acid-decomposable tertiary alkyl (meth)acrylate ester-based repeating unit (the repeating unit in which Xa1 represents a hydrogen atom or a methyl group, and T represents a single bond).
The content of the repeating unit containing an acid-decomposable group is preferably 15% by mole or greater, more preferably 20% by mole or greater, still more preferably 25% by mole or greater, and particularly preferably 30% by mole or greater with respect to all repeating units in the resin (A). In addition, the upper limit thereof is not particularly limited, but is preferably 90% by mole or less, more preferably 80% by mole or less, and still more preferably 70% by mole or less.
Specific examples of the repeating unit having an acid-decomposable group are shown below, but the present invention is not limited thereto. Further, in the formulae, Xa1 represents H, CH3, CF3, or CH2OH, and Rxa and Rxb each represent a linear or branched chain alkyl group having 1 to 5 carbon atoms.
The resin (A) may include a repeating unit other than the above-described repeating units.
In a case where the resist composition is used for EUV exposure or electron beam exposure, it is preferable that the resin (A) has at least one repeating unit selected from the group consisting of the group A.
<<Repeating Unit Containing Acid Group>>
The repeating unit having an acid group may have a fluorine atom or an iodine atom.
As the repeating unit having an acid group, a repeating unit represented by Formula (B) is preferable.
R3 represents a hydrogen atom or a monovalent organic group which may have a fluorine atom or an iodine atom.
R4 and R5 each independently represent a hydrogen atom, a fluorine atom, an iodine atom, or an alkyl group which may have a fluorine atom or an iodine atom.
L2 represents a single bond or an ester group.
As the repeating unit having an acid group, a repeating unit represented by General Formula (I) is also preferable.
In General Formula (I), R41, R42, and R43 each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group, or an alkoxycarbonyl group. Here, R42 may be bonded to Ar4 to form a ring, and in this case, R42 represents a single bond or an alkylene group.
As the alkyl group represented by each of R41, R42, and R43 in General Formula (I), an alkyl group having 20 or less carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, and a dodecyl group is preferable, an alkyl group having 8 or less carbon atoms is more preferable, and an alkyl group having 3 or less carbon atoms is still more preferable.
The cycloalkyl group as R41, R42, and R43 in General Formula (I) may be monocyclic or polycyclic. Among these, a monocyclic cycloalkyl group having 3 to 8 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group, is preferable.
Preferred examples of the substituent in each of the groups include an alkyl group, a cycloalkyl group, an aryl group, an amino group, an amide group, a ureide group, a urethane group, a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group, a thioether group, an acyl group, an acyloxy group, an alkoxycarbonyl group, a cyano group, and a nitro group. The substituent has preferably 8 or less carbon atoms.
Ar4 represents an (n+1)-valent aromatic ring group. The divalent aromatic ring group in a case where n is 1 is preferably, for example, an arylene group having 6 to 18 carbon atoms, such as a phenylene group, a tolylene group, a naphthylene group, and an anthracenylene group, or a divalent aromatic ring group including a heterocycle such as a thiophene ring, a furan ring, a pyrrole ring, a benzothiophene ring, a benzofuran ring, a benzopyrrole ring, a triazine ring, an imidazole ring, a benzimidazole ring, a triazole ring, a thiadiazole ring, and a thiazole ring. Furthermore, the aromatic ring group may have a substituent.
Specific examples of the (n+1)-valent aromatic ring group in a case where n is an integer of 2 or greater include groups formed by removing any (n−1) hydrogen atoms from the above-described specific examples of the divalent aromatic ring group.
Examples of the substituent which can be contained in the alkyl group, the cycloalkyl group, the alkoxycarbonyl group, the alkylene group, and the (n+1)-valent aromatic ring group, each mentioned above, include the alkyl groups; the alkoxy groups such as a methoxy group, an ethoxy group, a hydroxyethoxy group, a propoxy group, a hydroxypropoxy group, and a butoxy group; the aryl groups such as a phenyl group; and the like, as mentioned for each of R41, R42, and R43 in General Formula (I).
As the alkylene group in L4, an alkylene group having 1 to 8 carbon atoms, such as a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, and an octylene group, is preferable.
The repeating unit represented by General Formula (I) is preferably a repeating unit represented by General Formula (1).
In General Formula (1), A represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, or a cyano group.
Here, it is preferable that the resin contained in the resist composition has a hydroxystyrene-based repeating unit.
Examples of the repeating unit containing an acid group are shown below. In the formula, a represents 1 or 2.
Moreover, among the repeating units, the repeating units specifically described below are preferable. In the formula, R represents a hydrogen atom or a methyl group, and a represents 2 or 3.
The content of the repeating unit containing an acid group (preferably a hydroxystyrene-based repeating unit) is preferably 5% by mole or greater and more preferably 10% by mole or greater with respect to all repeating units in the resin (A). In addition, the upper limit thereof is not particularly limited, but is preferably 50% by mole or less, more preferably 45% by mole or less, and still more preferably 40% by mole or less.
<<Repeating Unit Having Fluorine Atom or Iodine Atom>>
As the repeating unit having a fluorine atom or an iodine atom, a repeating unit represented by Formula (C) is preferable.
L5 represents a single bond or an ester group.
The repeating unit having a fluorine atom or an iodine atom will be exemplified below.
The content of the repeating unit having a fluorine atom or an iodine atom is preferably 0% by mole or greater, more preferably 5% by mole or greater, and still more preferably 10% by mole or greater with respect to all the repeating units in the resin (A). In addition, an upper limit thereof is preferably 50% by mole or less, more preferably 45% by mole or less, and still more preferably 40% by mole or less.
The total content of the repeating units including at least one of a fluorine atom or an iodine atom in the repeating units of the resin (A) is preferably 20% by mole or greater, more preferably 30% by mole or greater, and still more preferably 40% by mole or greater with respect to all the repeating units of the resin (A). An upper limit thereof is not particularly limited, but is, for example, 100% by mole or less.
<<Repeating Unit Having Lactone Group, Sultone Group, or Carbonate Group>>
The lactone group or the sultone group may have a lactone structure or a sultone structure. The lactone structure or the sultone structure is preferably a 5- to 7-membered ring lactone structure or a 5- to 7-membered ring sultone structure. Among these, the structure is more preferably a 5- to 7-membered ring lactone structure with which another ring structure is fused so as to form a bicyclo structure or a Spiro structure or a 5- to 7-membered ring sultone structure with which another ring structure is fused so as to form a bicyclo structure or a Spiro structure.
The moiety of the lactone structure or the sultone structure may have a substituent (Rb2). Preferred examples of the substituent (Rb2) include an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxycarbonyl group having 1 to 8 carbon atoms, a carboxyl group, a halogen atom, a hydroxyl group, a cyano group, and an acid-decomposable group. n2 represents an integer of 0 to 4. In a case where n2 represents 2 or greater, a plurality of Rb2's may be different from each other and the plurality of Rb2's may be bonded to each other to form a ring.
Examples of the repeating unit containing a group having the lactone structure represented by any of General Formulae (LC1-1) to (LC1-21) or the sultone structure represented by any of General Formulae (SL1-1) to (SL1-3) include a repeating unit represented by General Formula (AI).
In General Formula (AI), Rb0 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms.
In a case where an optical isomer is present in the repeating unit containing a lactone group or a sultone group, any optical isomer may be used. In addition, one optical isomer may be used alone or a mixture of a plurality of the optical isomers may be used. In a case where one kind of optical isomers is mainly used, an optical purity (ee) thereof is preferably 90 or greater, and more preferably 95 or greater.
As the carbonate group, a cyclic carbonic acid ester group is preferable.
In General Formula (A-1), RA1 represents a hydrogen atom, a halogen atom, or a monovalent organic group (preferably a methyl group).
The repeating unit having a lactone group, a sultone group, or a carbonate group will be exemplified below.
(In the formulae, Rx represents H, CH3, CH2OH, or CF3)
(In the formulae, Rx represents H, CH3, CH2OH, or CF3)
(In the formulae, Rx represents H, CH3, CH2OH, or CF3)
The content of the repeating unit containing a lactone group, a sultone group, or a carbonate group is preferably 1% by mole or greater and more preferably 5% by mole or greater with respect to all repeating units in the resin (A). In addition, the upper limit thereof is not particularly limited, but is preferably 65% by mole or less, more preferably 30% by mole or less, still more preferably 25% by mole or less, and particularly preferably 20% by mole or less.
<<Repeating Unit Having Photoacid Generating Group>>
R41 represents a hydrogen atom or a methyl group. L41 represents a single bond or a divalent linking group. L42 represents a divalent linking group. R40 represents a structural site that is decomposed upon irradiation with actinic rays or radiation and generates an acid in a side chain.
The repeating unit having a photoacid generating group is exemplified below.
In addition, examples of the repeating unit represented by General Formula (4) include the repeating units described in paragraphs [0094] to [0105] of JP2014-041327A.
The content of the repeating unit having a photoacid generating group is preferably 1% by mole or greater, and more preferably 5% by mole or greater with respect to all the repeating units in the resin (A). In addition, the upper limit thereof is preferably 40% by mole or less, more preferably 35% by mole or less, and still more preferably 30% by mole or less.
<<Repeating Unit Represented by General Formula (V-1) or General Formula (V-2)>>
In the formula, R6 and R7 each independently represent a hydrogen atom, a hydroxyl group, an alkyl group, an alkoxy group, an acyloxy group, a cyano group, a nitro group, an amino group, a halogen atom, an ester group (—OCOR or —COOR: R is an alkyl group or fluorinated alkyl group having 1 to 6 carbon atoms), or a carboxyl group. As the alkyl group, a linear, branched chain, or cyclic alkyl group having 1 to 10 carbon atoms is preferable.
<<Repeating Unit for Reducing Mobility of Main Chain>>
From the viewpoint of increasing the Tg of the resin (A) (preferably to raise the Tg to higher than 90° C.), it is preferable to reduce the mobility of the main chain of the resin (A). Examples of a method of lowering the mobility of the main chain of the resin (A) include the following (a) to (e) methods.
(Repeating Unit Represented by Formula (A))
In Formula (A), RA represents a group having a polycyclic structure. Rx represents a hydrogen atom, a methyl group, or an ethyl group. The group having a polycyclic structure is a group having a plurality of ring structures, and the plurality of ring structures may or may not be fused.
In the formulae, R represents a hydrogen atom, a methyl group, or an ethyl group.
(Repeating Unit Represented by Formula (B))
In Formula (B), Rb1 to Rb4 each independently represent a hydrogen atom or an organic group, and at least two or more of Rb1, . . . , or Rb4 represent an organic group.
Specific examples of the repeating unit represented by Formula (B) include the following repeating units.
In the formula, R's each independently represent a hydrogen atom or an organic group. Examples of the organic group include an organic group such as an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group, each of which may have a substituent.
(Repeating Unit Represented by Formula (C))
In Formula (C), Rc1 to Rc4 each independently represent a hydrogen atom or an organic group, and at least one of Rc1, . . . , or Rc4 is a group having a hydrogen-bonding hydrogen atom with a number of atoms of 3 or less from the main chain carbon. Among these, it is preferable that the group has hydrogen-bonding hydrogen atoms with a number of atoms of 2 or less (on a side closer to the vicinity of the main chain) to induce an interaction between the main chains of the resin (A).
Specific examples of the repeating unit represented by Formula (C) include the following repeating units.
In the formula, R represents an organic group. The organic group may have a substituent, and examples thereof include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, and an ester group (—OCOR or —COOR: R is an alkyl group or fluorinated alkyl group having 1 to 20 carbon atoms).
(Repeating Unit Represented by Formula (D))
In Formula (D), “Cyclic” represents a group that forms a main chain with a cyclic structure. The number of the ring-constituting atoms is not particularly limited.
Specific examples of the repeating unit represented by Formula (D) include the following repeating units.
In the formula, R's each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, a hydroxyl group, an alkoxy group, an acyloxy group, a cyano group, a nitro group, an amino group, a halogen atom, an ester group (—OCOR″ or —COOR″: R″ is an alkyl group or fluorinated alkyl group having 1 to 20 carbon atoms), or a carboxyl group. Further, the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, and the alkenyl group may each have a substituent. In addition, the hydrogen atom bonded to the carbon atom in the group represented by R may be substituted with a fluorine atom or an iodine atom.
(Repeating Unit Represented by Formula (E))
In Formula (E), Re's each independently represent a hydrogen atom or an organic group. Examples of the organic group include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group, each of which may have a substituent.
Specific examples of the repeating unit represented by Formula (E) include the following repeating units.
In the formulae, R's each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkenyl group, a hydroxyl group, an alkoxy group, an acyloxy group, a cyano group, a nitro group, an amino group, a halogen atom, an ester group (—OCOR″ or —COOR″: R″ is an alkyl group or fluorinated alkyl group having 1 to 20 carbon atoms), or a carboxyl group. Further, the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group, and the alkenyl group may each have a substituent. In addition, the hydrogen atom bonded to the carbon atom in the group represented by R may be substituted with a fluorine atom or an iodine atom.
The content of the repeating unit represented by Formula (E) is preferably 5% by mole or greater, and more preferably 10% by mole or greater with respect to all the repeating units in the resin (A). In addition, the upper limit thereof is preferably 60% by mole or less and more preferably 55% by mole or less.
<<Repeating Unit Having at Least One Group Selected from Lactone Group, Sultone Group, Carbonate Group, Hydroxyl Group, Cyano Group, and Alkali-Soluble Group>
The resin (A) may have a repeating unit having a hydroxyl group or a cyano group. As a result, the adhesiveness to a substrate and the affinity for a developer are improved.
In General Formulae (AIIa) to (AIId), R1c represents a hydrogen atom, a methyl group, a trifluoromethyl group, or a hydroxymethyl group.
The content of the repeating unit having a hydroxyl group or a cyano group is preferably 5% by mole or greater, and more preferably 10% by mole or greater with respect to all the repeating units in the resin (A). In addition, the upper limit thereof is preferably 40% by mole or less, more preferably 35% by mole or less, and still more preferably 30% by mole or less.
Specific examples of the repeating unit having a hydroxyl group or a cyano group are shown below, but the present invention is not limited thereto.
The resin (A) may have a repeating unit having an alkali-soluble group.
The content of the repeating unit having an alkali-soluble group is preferably 0% by mole or greater, more preferably 3% by mole or greater, and still more preferably 5% by mole or greater with respect to all the repeating units in the resin (A). An upper limit thereof is preferably 20% by mole or less, more preferably 15% by mole or less, and still more preferably 10% by mole or less.
Specific examples of the repeating unit having an alkali-soluble group are shown below, but the present invention is not limited thereto. In the specific examples, Rx represents H, CH3, CH2OH, or CF3.
As the repeating unit having at least one group selected from a lactone group, a hydroxyl group, a cyano group, and an alkali-soluble group, a repeating unit having at least two selected from a lactone group, a hydroxyl group, a cyano group, and an alkali-soluble group is preferable, a repeating unit having a cyano group and a lactone group is more preferable, and a repeating unit having a structure in which a cyano group is substituted in the lactone structure represented by General Formula (LC1-4) is still more preferable.
<<Repeating Unit Having Alicyclic Hydrocarbon Structure and not Exhibiting Acid Decomposability>>
<<Repeating Unit Represented by General Formula (III) Containing None of Hydroxyl Group or Cyano Group)
In General Formula (III), R5 represents a hydrocarbon group having at least one cyclic structure and having neither a hydroxyl group nor a cyano group.
The cyclic structure contained in R5 includes a monocyclic hydrocarbon group and a polycyclic hydrocarbon group. Examples of the monocyclic hydrocarbon group include a cycloalkyl group having 3 to 12 carbon atoms (more preferably 3 to 7 carbon atoms) or a cycloalkenyl group having 3 to 12 carbon atoms.
Examples of the polycyclic hydrocarbon group include a ring assembly hydrocarbon group and a crosslinked cyclic hydrocarbon group.
The alicyclic hydrocarbon group may have a substituent, and examples of the substituent include a halogen atom, an alkyl group, a hydroxyl group protected by a protective group, and an amino group protected by a protective group.
Examples of the protective group include an alkyl group, a cycloalkyl group, an aralkyl group, a substituted methyl group, a substituted ethyl group, an alkoxycarbonyl group, and an aralkyloxycarbonyl group.
The content of the repeating unit represented by General Formula (III), which has neither a hydroxyl group nor a cyano group, is preferably 0% to 40% by mole, and more preferably 0% to 20% by mole with respect to all repeating units in the resin (A).
<<Other Repeating Units>>
The resin (A) may have a variety of repeating structural units, in addition to the repeating structural units described above, for the purpose of adjusting dry etching resistance, suitability for a standard developer, adhesiveness to a substrate, a resist profile, resolving power, heat resistance, sensitivity, and the like.
As the resin (A), it is also preferable that all repeating units are formed of (meth)acrylate-based repeating units (particularly in a case where the composition is used for ArF exposure). In this case, any of a resin in which all the repeating units are methacrylate-based repeating units, a resin in which all the repeating units are acrylate-based repeating units, or a resin in which all the repeating units are methacrylate-based repeating units and acrylate-based repeating units can be used, and it is preferable that the amount of the acrylate-based repeating units is 50% by mole or less with respect to all the repeating units.
The resin (A) can be synthesized in accordance with an ordinary method (for example, radical polymerization).
The content of the resin (A) in the resist composition is preferably 50% to 99.9% by mass, and more preferably 60% to 99.0% by mass with respect to the total solid content of the composition.
<Compound that Generates Acid with Actinic Rays or Radiation (Photoacid Generator)>
In General Formula (ZI), R201, R202, and R203 each independently represent an organic group.
Examples of the non-nucleophilic anion include a sulfonate anion (such as an aliphatic sulfonate anion, aromatic sulfonate anion, and a camphorsulfonate anion), a carboxylate anion (such as an aliphatic carboxylate anion, an aromatic carboxylate anion, and an aralkyl carboxylate anion), a sulfonylimide anion, a bis(alkylsulfonyl)imide anion, and a tris(alkylsulfonyl)methide anion.
The aliphatic moiety in the aliphatic sulfonate anion and the aliphatic carboxylate anion may be an alkyl group or a cycloalkyl group, and preferred examples thereof include a linear or branched chain alkyl group having 1 to 30 carbon atoms and a cycloalkyl group having 3 to 30 carbon atoms.
As the aromatic group in the aromatic sulfonate anion and the aromatic carboxylate anion, an aryl group having 6 to 14 carbon atoms is preferable, and examples thereof include a phenyl group, a tolyl group, and a naphthyl group.
The alkyl group, the cycloalkyl group, and the awl group exemplified above may have a substituent. Specific examples of the substituent include a nitro group, a halogen atom such as fluorine atom, a carboxyl group, a hydroxyl group, an amino group, a cyano group, an alkoxy group (preferably having 1 to 15 carbon atoms), a cycloalkyl group (preferably having 3 to 15 carbon atoms), an awl group (preferably having 6 to 14 carbon atoms), an alkoxycarbonyl group (preferably having 2 to 7 carbon atoms), an acyl group (preferably having 2 to 12 carbon atoms), an alkoxycarbonyloxy group (preferably having 2 to 7 carbon atoms), an alkylthio group (preferably having 1 to 15 carbon atoms), an alkylsulfonyl group (preferably having 1 to 15 carbon atoms), an alkyliminosulfonyl group (preferably having 1 to 15 carbon atoms), an aryloxysulfonyl group (preferably having 6 to 20 carbon atoms), an alkylaryloxysulfonyl group (preferably having 7 to 20 carbon atoms), a cycloalkylaryloxysulfonyl group (preferably having 10 to 20 carbon atoms), an alkyloxyalkyloxy group (preferably having 5 to 20 carbon atoms), and a cycloalkylalkyloxyalkyloxy group (preferably having 8 to 20 carbon atoms).
As the aralkyl group in the aralkylcarboxylate anion, an aralkyl group having 7 to 12 carbon atoms is preferable, and examples thereof include a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group, and a naphthylbutyl group.
Examples of the sulfonylimide anion include a saccharin anion.
As the alkyl group in the bis(alkylsulfonyl)imide anion and the tris(alkylsulfonyl)methide anion, an alkyl group having 1 to 5 carbon atoms is preferable. Examples of substituents of these alkyl groups include a halogen atom, an alkyl group substituted with a halogen atom, an alkoxy group, an alkylthio group, an alkyloxysulfonyl group, an aryloxysulfonyl group, and a cycloalkylaryloxysulfonyl group. Among these, a fluorine atom or an alkyl group substituted with a fluorine atom is preferable.
Examples of other non-nucleophilic anions include fluorinated phosphorus (for example, PF6−), fluorinated boron (for example, BF4−), and fluorinated antimony (for example, SbF6−).
As the non-nucleophilic anion, an aliphatic sulfonate anion in which at least an α-position of the sulfonic acid is substituted with a fluorine atom, an aromatic sulfonate anion substituted with a fluorine atom or a group having a fluorine atom, a bis(alkylsulfonyl)imide anion in which an alkyl group is substituted with a fluorine atom, or a tris(alkylsulfonyl)methide anion in which an alkyl group is substituted with a fluorine atom is preferable. As the non-nucleophilic anion, a perfluoroaliphatic sulfonate anion (still more preferably having 4 to 8 carbon atoms) or a benzene sulfonate anion having a fluorine atom is more preferable, and a nonafluorobutane sulfonate anion, a perfluorooctane sulfonate anion, a pentafluorobenzene sulfonate anion, or a 3,5-bis(trifluoromethyl) benzene sulfonate anion is still more preferable.
From the viewpoint of the acid strength, it is preferable that the pKa of the acid generated is −1 or less to improve the sensitivity.
Moreover, an anion represented by General Formula (AN1) may also be mentioned as a preferred aspect of the non-nucleophilic anion.
Xf's each independently represent a fluorine atom or an alkyl group substituted with at least one fluorine atom.
General Formula (AN1) will be described in more detail.
The alkyl group as R1 and R2 may have a substituent (preferably a fluorine atom), and preferably has 1 to 4 carbon atoms. The alkyl group is more preferably a perfluoroalkyl group having 1 to 4 carbon atoms. Specific examples of the alkyl group having a substituent as R1 and R2 include CF3, C2F5, C3F7, C4F9, C5F11, C6F13, C7F15, C8F17, CH2CF3, CH2CH2CF3, CH2C2F5, CH2CH2C2F5, CH2C3F7, CH2CH2C3F7, CH2C4F9, and CH2CH2C4F9. Among these, CF3 is preferable.
x is preferably 1 to 10, and more preferably 1 to 5.
In General Formula (AN1), preferred examples of a combination of partial structures other than A include SO3-—CF2—CH2—OCO—, SO3-—CF2—CHF—CH2—OCO—, SO3-—CF2—COO—, SO3-—CF2—CF2—CH2—, and SO3-—CF2—CH(CF3)—OCO—.
The cyclic organic group as A is not particularly limited as long as the cyclic organic group has a cyclic structure, and examples thereof include an alicyclic group, an aryl group, and a heterocyclic group (also including a group having aromaticity as well as a group having no aromaticity).
Moreover, examples of the cyclic organic group also include a lactone structure, and specific examples thereof include lactone structures represented by General Formulae (LC1-1) to (LC1-17).
The cyclic organic group may have a substituent, and examples of the substituent include an alkyl group (any of linear, branched chain, or cyclic and preferably having 1 to 12 carbon atoms), a cycloalkyl group (any of a monocycle, a polycycle, or a Spiro ring and preferably having 3 to 20 carbon atoms), an aryl group (preferably having 6 to 14 carbon atoms), a hydroxy group, an alkoxy group, an ester group, an amide group, a urethane group, a ureido group, a thioether group, a sulfonamide group, and a sulfonic acid ester group. Incidentally, the carbon constituting the cyclic organic group (carbon contributing to ring formation) may be carbonyl carbon.
In General Formula (ZI), examples of the organic groups of R201, R202, and R203 include an aryl group, an alkyl group, and a cycloalkyl group.
Next, General Formulae (ZII) and (ZIII) will be described.
The awl group, the alkyl group, and the cycloalkyl group as R204 to R207 may have a substituent. Examples of the substituent that the aryl group, alkyl group and cycloalkyl group as R204 to R207 may have include an alkyl group (for example, having 1 to 15 carbon atoms) and a cycloalkyl group (for example, having 3 to 15 carbon atoms), an aryl group (for example, having 6 to 15 carbon atoms), an alkoxy group (for example, having 1 to 15 carbon atoms), a halogen atom, a hydroxyl group, and a phenylthio group.
Furthermore, in General Formula (ZII), Z− represents a non-nucleophilic anion. Specifically, Z− is the same as those described as Z− in General Formula (ZI), preferred aspects thereof are also the same.
Specific examples of General Formulae (ZI) to (ZIII) are shown below, but are not limited thereto.
In the present invention, from the viewpoint of suppressing the diffusion of an acid generated by exposure to a unexposed area and improving the resolution, the photoacid generator is a compound which generates an acid (more preferably sulfonic acid) having a volume of 130 Å3 or greater upon irradiation with electron beams or extreme ultraviolet rays, more preferably a compound which generates an acid (more preferably sulfonic acid) having a volume of 190 Å3 or greater, still more preferably a compound which generates an acid (more preferably sulfonic acid) having a volume of 270 Å3 or greater, and particularly preferably a compound which generates an acid (more preferably sulfonic acid) having a volume of 400 Å3 or greater. From the viewpoint of the sensitivity or the solubility in the coating solvent, the volume is preferably 2,000 Å3 or less and more preferably 1,500 Å3 or less. The value of the volume is acquired using “WinMOPAC” (manufactured by FUJITSU). That is, first, the chemical structure of an acid according to each example is input, next, using this structure as an initial structure, the most stable steric conformation of each acid is determined by molecular force field calculation using an MM3 method, and then, molecular orbital calculation using a PM3 method is performed with respect to the most stable steric conformation, whereby an “accessible volume” of each acid can be calculated. In addition, 1 Å denotes 0.1 nm.
In the present invention, photoacid generators which generate acids exemplified below upon irradiation with actinic rays or radiation are preferable. Further, in some of the examples, the calculated values of the volumes are added (unit: Å3). The calculated value obtained here is a volume value of an acid in which a proton is bonded to the anionic moiety.
With regard to the photoacid generator, reference can be made to paragraphs <0368> to <0377> of JP2014-41328A and paragraphs <0240> to <0262> of JP2013-228681A (corresponding to <0339> of US2015/004533A), the contents of which are incorporated herein by reference. Specifically, for example, the following compounds are also preferable, but the present invention is not limited thereto.
The photoacid generator may be used singly or in combination of two or more kinds thereof.
<Solvent>
Preferred examples of the alkylene glycol monoalkyl ether carboxylate include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol monoethyl ether propionate, ethylene glycol monomethyl ether acetate, and ethylene glycol monoethyl ether acetate.
Preferred examples of the alkyl lactate include methyl lactate, ethyl lactate, propyl lactate, and butyl lactate.
Preferred examples of the cyclic lactone having 4 to 10 carbon atoms include β-propiolactone, β-butyrolactone, γ-butyrolactone, α-methyl-γ-butyrolactone, β-methyl-γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-octanolactone, and α-hydroxy-γ-butyrolactone.
Preferred examples of the monoketone compound having 4 to 10 carbon atoms, which may have a ring, include 2-butanone, 3-methylbutanone, pinacolone, 2-pentanone, 3-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2-methyl-3-pentanone, 4,4-dimethyl-2-pentanone, 2,4-dimethyl-3-pentanone, 2,2,4,4-tetramethyl-3-pentanone, 2-hexanone, 3-hexanone, 5-methyl-3-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-methyl-3-heptanone, 5-methyl-3-heptanone, 2,6-dimethyl-4-heptanone, 2-octanone, 3-octanone, 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 3-decanone, 4-decanone, 5-hexen-2-one, 3-penten-2-one, cyclopentanone, 2-methylcyclopentanone, 3-methylcyclopentanone, 2,2-dimethylcyclopentanone, 2,4,4-trimethylcyclopentanone, cyclohexanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 4-ethylcyclohexanone, 2,2-dimethylcyclohexanone, 2,6-dimethylcyclohexanone, 2,2,6-trimethylcyclohexanone, cycloheptanone, 2-methylcycloheptanone, and 3-methylcycloheptanone.
Preferred examples of the alkylene carbonate include propylene carbonate, vinylene carbonate, ethylene carbonate, and butylene carbonate.
In the present invention, a mixed solvent obtained by mixing a solvent containing a hydroxyl group in a structure and a solvent containing no hydroxyl group may be used as the organic solvent.
A mixed solvent of two or more kinds of the solvents containing propylene glycol monomethyl ether acetate is preferable as the solvent. Among these, a combination of γ-butyl lactone and butyl acetate is particularly preferable.
As the solvent, for example, the solvents described in paragraphs 0013 to 0029 of JP2014-219664A can also be used.
<Acid Diffusion Control Agent>
Examples of the acid diffusion control agent include a basic compound.
In General Formulae (A1) and (E1), R200, R201 and R202 may be the same as or different from each other and each represent a hydrogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), a cycloalkyl group (preferably having 3 to 20 carbon atoms), or an aryl group (preferably having 6 to 20 carbon atoms). Here, R201 and R202 may be bonded to each other to form a ring.
With regard to the alkyl group, the alkyl group having a substituent is preferably an aminoalkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 1 to 20 carbon atoms, or a cyanoalkyl group having 1 to 20 carbon atoms.
Preferred examples of the compound include a compound having an imidazole structure, a diazabicyclo structure, an onium hydroxide structure, an onium carboxylate structure, a trialkylamine structure, an aniline structure, or a pyridine structure, an alkylamine derivative having a hydroxyl group and/or an ether bond, and an aniline derivative having a hydroxyl group and/or an ether bond in addition to guanidine, aminopyrrolidine, pyrazole, pyrazoline, piperazine, aminomorpholine, aminoalkylmorpholine, and piperidine.
Examples of the compound having an imidazole structure include imidazole, 2,4,5-triphenylimidazole, and benzimidazole. Examples of the compound having a diazabicyclo structure include 1,4-diazabicyclo[2,2,2]octane, 1,5-diazabicyclo[4,3,0]nona-5-ene, and 1,8-diazabicyclo[5,4,0]undeca-7-ene. Examples of the compound having an onium hydroxide structure include triarylsulfonium hydroxide, phenacyl sulfonium hydroxide, sulfonium hydroxide having a 2-oxoalkyl group, and specifically, triphenylsulfonium hydroxide, tris(t-butylphenyl)sulfonium hydroxide, bis(t-butylphenyl)iodonium hydroxide, phenacylthiophenium hydroxide, and 2-oxopropylthiophenium hydroxide. The compound having an onium carboxylate structure is a compound in which the anionic moiety of the compound having an onium hydroxide structure is a carboxylate, and examples thereof include acetate, adamantane-1-carboxylate, and perfluoroalkyl carboxylate. Examples of the compound having a trialkylamine structure include tri(n-butyl)amine and tri(n-octyl)amine. Examples of the aniline compound include 2,6-diisopropylaniline, N,N-dimethylaniline, N,N-dibutylaniline, and N,N-dihexylaniline. Examples of the alkylamine derivative having a hydroxyl group and/or an ether bond include ethanolamine, diethanolamine, triethanolamine, and tris(methoxyethoxyethyl)amine. Examples of the aniline derivative having a hydroxyl group and/or an ether bond include N,N-bis(hydroxyethyl)aniline
Other examples of the basic compound include an amine compound containing a phenoxy group and an ammonium salt compound containing a phenoxy group.
As the amine compound, a primary, secondary, or tertiary amine compound can be used, and an amine compound having at least one alkyl group bonded to the nitrogen atom thereof is preferable. The amine compound is more preferably a tertiary amine compound. Any amine compound is available as long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, and a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 6 to 12 carbon atoms), in addition to the alkyl group, may be bonded to the nitrogen atom.
As the ammonium salt compound, a primary, secondary, tertiary, or quaternary ammonium salt compound can be used. An ammonium salt compound having at least one alkyl group bonded to the nitrogen atom thereof is preferable. Any ammonium salt compound is available as long as at least one alkyl group (preferably having 1 to 20 carbon atoms) is bonded to a nitrogen atom, and a cycloalkyl group (preferably having 3 to 20 carbon atoms) or an aryl group (preferably having 6 to 12 carbon atoms) may be bonded to the nitrogen atom, in addition to the alkyl group.
The amine compound with a phenoxy group and the ammonium salt compound with a phenoxy group are those having a phenoxy group at the terminal of the alkyl group of each of the amine compound and the ammonium salt compound opposite to the nitrogen atom. The phenoxy group may have a substituent. Examples of the substituent of the phenoxy group include an alkyl group, an alkoxy group, a halogen atom, a cyano group, a nitro group, a carboxyl group, a carboxylic acid ester group, a sulfonic acid ester group, an aryl group, an aralkyl group, an acyloxy group, and an aryloxy group. The substitution position of the substituent may be any of 2- to 6-positions. The number of the substituents may be any in the range of 1 to 5.
This compound preferably has at least one oxyalkylene group between the phenoxy group and the nitrogen atom. The number of oxyalkylene groups per molecule may be 1 or more, and is preferably 3 to 9, and more preferably 4 to 6. Among the oxyalkylene groups, an oxyethylene group (—CH2CH2O—) or an oxypropylene group (—CH(CH3)CH2O— or —CH2CH2CH2O—) is preferable, and the oxyethylene group is more preferable.
The amine compound having a phenoxy group can be obtained by heating a primary or secondary amine having a phenoxy group with a haloalkyl ether to make a reaction, and then adding an aqueous solution of a strong base such as sodium hydroxide, potassium hydroxide, and tetraalkylammonium thereto, followed by extraction with an organic solvent such as ethyl acetate and chloroform. Alternatively, the amine compound having a phenoxy group can be obtained by heating a primary or secondary amine with a haloalkyl ether having a phenoxy group at a terminal thereof to make a reaction, and then adding an aqueous solution of a strong base such as sodium hydroxide, potassium hydroxide, and tetraalkylammonium thereto, followed by extraction with an organic solvent such as ethyl acetate and chloroform.
(Compound (PA) that contains proton-accepting functional group and is decomposed upon irradiation with actinic rays or radiation to generate compound in which proton-accepting properties are degraded and lost or proton-accepting properties are changed to acidic properties)
The proton accepting functional group is a group capable of electrostatically interacting with a proton, or a functional group having an electron, and for example, the proton acceptor functional group means a functional group having a macrocyclic structure such as a cyclic polyether, or a functional group having a nitrogen atom with an unshared electron pair which does not contribute to π-conjugation. The nitrogen atom having an unshared electron pair not contributing to π-conjugation is, for example, a nitrogen atom having a partial structure represented by the following general formula.
Preferred examples of the partial structure of the proton-accepting functional group include crown ether, azacrown ether, primary to tertiary amines, pyridine, imidazole, and a pyrazine structure.
The compound (PA) is decomposed upon irradiation with actinic rays or radiation to generate a compound in which the proton-accepting properties are degraded and lost or the proton-accepting properties are changed to acidic properties. Here, the expression “the proton-accepting properties are degraded and lost or the proton-accepting properties are changed to acidic properties” denotes a change of proton-accepting properties due to addition of the proton to the proton-accepting functional group, and specifically a decrease in the equilibrium constant at chemical equilibrium in a case where a proton adduct is generated from the compound (PA) containing the proton-accepting functional group and the proton.
Specific examples of the compound (PA) include the following compounds. Further, with regard to specific examples of the compound (PA), reference can be made to those described in paragraphs 0421 to 0428 of JP2014-41328A or paragraphs 0108 to 0116 of JP2014-134686A, the contents of which are incorporated herein by reference.
The acid diffusion control agent may be used alone or in combination of two or more kinds thereof
The ratio of the photoacid generator to the acid diffusion control agent used in the composition (photoacid generator/acid diffusion control agent (molar ratio)) is preferably in a range of 2.5 to 300. That is, the molar ratio is preferably 2.5 or greater in view of sensitivity and resolution, and is preferably 300 or less in view of suppressing the reduction in resolution due to thickening of the resist pattern over time from exposure to the heat treatment. The photoacid generator/acid diffusion control agent (molar ratio) is more preferably 5.0 to 200, and still more preferably 7.0 to 150.
As the acid diffusion control agent, for example, the compounds (amine compounds, amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like) described in paragraphs 0140 to 0144 of JP2013-11833A can also be used.
<Hydrophobic Resin>
From the viewpoint of localization on the film surface layer, the hydrophobic resin includes preferably one or more kinds and more preferably two or more kinds among “a fluorine atom”, “a silicon atom”, and “a CH3 partial structure included in a side chain of the resin”. Further, it is preferable that the hydrophobic resin contains a hydrocarbon group having 5 or more carbon atoms. These groups may be contained in the main chain of the resin or may be substituted in the side chain.
In a case where the hydrophobic resin includes a fluorine atom and/or a silicon atom, the fluorine atom and/or the silicon atom in the hydrophobic resin may be present at a main chain or a side chain of the resin.
In a case where the hydrophobic resin includes a fluorine atom, it is preferably a resin which has an alkyl group having a fluorine atom, a cycloalkyl group having a fluorine atom, or an aryl group having a fluorine atom as a partial structure having a fluorine atom.
The alkyl group having a fluorine atom (preferably having 1 to 10 carbon atoms and more preferably having 1 to 4 carbon atoms) is a linear or branched chain alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have a substituent other than a fluorine atom.
The cycloalkyl group having a fluorine atom is a monocyclic or polycyclic cycloalkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and may further have a substituent other than a fluorine atom.
Examples of the aryl group having a fluorine atom include an aryl group such as a phenyl group or a naphthyl group, in which at least one hydrogen atom is substituted with a fluorine atom, and may further have a substituent other than a fluorine atom.
Examples of a repeating unit having a fluorine atom or a silicon atom include those exemplified in paragraph 0519 of US2012/0251948A1.
Furthermore, as described above, it is also preferable that the hydrophobic resin includes a CH3 partial structure in a side chain moiety.
With regard to the hydrophobic resin, reference can be made to the description in <0348> to <0415> of JP2014-010245A, the contents of which are incorporated herein by reference.
Further, the resins described in JP2011-248019A, JP2010-175859A, and/or JP2012-032544A, in addition to those described above, can also be preferably used as the hydrophobic resin.
<Surfactant>
Moreover, in addition to the known surfactants as shown above, a surfactant may be synthesized using a fluoroaliphatic compound produced using a telomerization method (also referred to as a telomer method) or an oligomerization method (also referred to as an oligomer method). Specifically, a polymer containing a fluoroaliphatic group derived from fluoroaliphatic compound may be used as the surfactant. The fluoroaliphatic compound can be synthesized in accordance with the method described in JP2002-90991A.
These surfactants may be used alone or in combination of two or more kinds thereof.
In a case where the resist composition contains a surfactant, the content thereof is preferably in a range of 0% to 2% by mass, more preferably in a range of 0.0001% to 2% by mass, and still more preferably in a range of 0.0005% to 1% by mass with respect to the total solid content of the composition.
<Other Additives>
The resist composition may further include a dissolution inhibiting compound.
[Method of Producing Treatment Liquid]
<Purifying Step>
Hereinafter, an example of the purifying step will be presented. In the following description, the purification targets in the purifying step are simply collectively referred to as “the liquid to be purified”.
According to the first ion exchange treatment, it is possible to remove the ion components (for example, the metal component) in the liquid to be purified.
By the dehydration treatment, it is possible to remove water in the liquid to be purified. Further, in a case where zeolite described below (in particular, Molecular Sieve (trade name), manufactured by Union Showa K. K., or the like) is used in the dehydration treatment, olefins can also be removed.
According to the distillation treatment, it is possible to remove impurities eluted from the dehydrating film, the metal component in the liquid to be purified, which is hardly removed in the first ion exchange treatment, fine particles (in a case where the metal component is a fine particle, it is also included), and water in the liquid to be purified.
According to the second ion exchange treatment, impurities can be removed in a case where the impurities accumulated in the distillation device flow out or eluates can be removed from pipes made of stainless steel (SUS) or the like used as a liquid feeding line.
Each of the above-described treatments is preferably performed in an inert gas atmosphere which is in a closed state and has a low potential of incorporation of water into the liquid to be purified.
Examples of the purifying step include a treatment for absorbing and purifying the metal component using silicon carbide, described in WO2012/043496A, in addition to the above-described treatments.
According to the organic impurity removing treatment, high-boiling point organic impurities and the like (including organic substances having a boiling point of 300° C. or higher) that are contained in the liquid to be purified after the distillation treatment and are difficult to remove by the distillation treatment can be removed.
Further, the organic impurity removing treatment is not limited to an aspect of using the organic impurity adsorption filter capable of adsorbing the organic impurities as described above, and for example, an aspect of physically trapping the organic impurities may be employed. Since organic impurities having a relatively high boiling point of 250° C. or higher are coarse in many cases (for example, a compound having 8 or more carbon atoms), the organic impurities can be physically trapped by using a filter having a pore diameter of approximately 1 nm.
Further, the purifying step may further include a purification treatment V and a purification treatment VI described below. The purification treatment V and the purification treatment VI may be carried out at any timing, for example, after the purifying step IV or the like.
Examples of the metal ion removal means in the purification treatment VI include filtering with a metal ion adsorption member provided with a metal ion adsorption filter.
As the filtration means in the purification treatment VI, an aspect in which the filtration is performed using a filtration member provided with a filter having a particle removal diameter of 20 nm or less is exemplified. Particulate impurities can be removed from the liquid to be purified by adding the above-described filter. Here, examples of “particulate impurities” include particles such as dust, dirt, organic solids, and inorganic solids contained as impurities in the raw materials used during the production of the liquid to be purified and particles such as dust, dirt, organic solids, and inorganic solids brought in as a contaminant during the purification of the liquid to be purified, and the particulate impurities correspond to those that finally exist as particles without being dissolved in the liquid to be purified.
The filtration member may further include a filter having a particle removal diameter of 50 nm or greater (for example, a microfiltration film for removing fine particles having a pore diameter of 50 nm or greater). In a case where fine particles are present in the liquid to be purified in addition to colloidized impurities, in particular, colloidized impurities having metal atoms such as iron and aluminum, the filtering efficiency of a filter having a particle removal diameter of 20 nm or less (for example, a microfiltration film having a pore diameter of 20 nm or less) is improved and the performance of removing coarse particles is further improved, by carrying out the filtration of the liquid to be purified using a filter having a particle removal diameter of 50 nm or greater (for example, a microfiltration film for removing fine particles, having a pore diameter of 50 nm or greater) before performing filtration using a filter having a particle removal diameter of 20 nm or less (for example, a microfiltration film having a pore diameter of 20 nm or less).
The liquid to be purified obtained by performing each of the treatments can be used in the preparation of the treatment liquid according to the embodiment of the present invention or can be used as the treatment liquid according to the embodiment of the present invention as it is.
[Container (Accommodation Container)]
Further, as the inner wall of the container, a quartz or metal material (more preferably, an electropolished metal material, that is, a metal material after completion of electropolishing) is also preferably used in addition to the above-described nonmetallic material.
The stainless steel is not particularly limited, and known stainless steel can be used as the stainless steel.
As the method of electropolishing the metal material, known methods can be used without particular limitation. For example, the methods described in paragraphs <0011> to <0014> in JP2015-227501A, paragraphs <0036> to <0042> in JP2008-264929A, and the like can be used.
In a case where the metal material is electropolished, it is presumed that the content of chromium in a passivation layer on a surface is greater than the content of chromium in a primary phase. Therefore, it is presumed that since the metal component is unlikely to flow out into the treatment liquid from the inner wall coated with the electropolished metal material, a solution with a reduced amount of the metal component (metal impurities) can be obtained.
In the present invention, the container, and the treatment liquid accommodated in the container may be referred to as a solution container in some cases.
The inside of these containers is preferably washed before the containers are filled with the treatment liquid. In a case where the liquid used for washing is the treatment liquid according to the embodiment of the present invention or the organic solvent contained in the treatment liquid according to the embodiment of the present invention, the effects of the present invention can be remarkably obtained. The treatment liquid according to the embodiment of the present invention may be bottled in a container such as a gallon bottle and a quart bottle after the production, transported, and stored. The gallon bottle may be formed of a glass material or other materials.
In order to prevent a change in the components of the treatment liquid during the storage, the inside of the container may be substituted with inert gas (nitrogen, argon, or the like) with a purity of 99.99995% by volume or greater. Particularly, a gas with a low moisture content is preferable. In addition, during the transportation or storage, the temperature may be controlled to room temperature or to be in a range of −20° C. to 20° C. to prevent deterioration.
[Clean Room]
[Electricity Removing Step]
The electricity removing step may be performed at any time from the supply of the raw material to the filling of the purified product, and it is preferable that the electricity removing step is performed before at least one step selected from the group consisting of, for example, a raw material supply step, a reaction step, a liquid preparing step, a purifying step, a filtering step, and a filling step. In particular, it is preferable that the electricity removing step is performed before a purified product or the like is injected into the container used in each of the above-described steps. In this manner, it is possible to suppress impurities derived from the container or the like from being mixed into the purified product or the like.
Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.
[Actinic Ray-Sensitive or Radiation-Sensitive Composition (Resist Composition)]
<Resin (A)>
The reaction solution (contents in the flask) was cooled to room temperature and added dropwise to hexane (3 L), thereby obtaining a mixed solution in which the polymer was precipitated. The mixed solution was filtered to obtain a solid (filtered material). The obtained solid (filtered material) was dissolved in acetone (500 ml) and added dropwise to hexane (3 L) again to obtain a solid (filtered material) again in the same manner as described above. The obtained solid was dried under reduced pressure, thereby obtaining a copolymer (A-1a) (160 g) of 4-acetoxystyrene/1-ethylcyclopentyl methacrylate/monomer 1.
The copolymer (A-1a) (10 g), methanol (40 ml), 1-methoxy-2-propanol (200 ml), and concentrated hydrochloric acid (1.5 ml) obtained in the above-described manner were added to an empty flask, and the reaction solution (contents in the flask) was heated to 80° C. and stirred for 5 hours. The reaction solution was allowed to be naturally cooled to room temperature and added dropwise to distilled water (3 L), thereby obtaining a mixed solution. The mixed solution was filtered to obtain a solid (filtered material). The obtained solid (filtered material) was dissolved in acetone (200 ml) and added dropwise again in distilled water (3 L), thereby obtaining a solid (filtered material) again in the same manner as described above. The obtained solid was dried under reduced pressure to obtain the resin (A-1) (8.5 g). The weight-average molecular weight of the resin (A-1) was 10800 and the molecular weight dispersion (Mw/Mn) thereof was 1.55.
The resins used in the resist composition are listed in the following table.
<Photoacid Generator>
The following components were used as the photoacid generator.
<Basic Compound (Acid Diffusion Control Agent)>
<Solvent>
<Other Additives>
<Preparation of Resist Composition>
Each component listed in Table 2 below was dissolved in the solvent listed in the same table with the formulation listed in the same table. The obtained mixed solution was filtered using a polyethylene filter having a pore diameter of 0.03 μm to obtain resist compositions 1 to 7.
[Tests]
<Preparation of Pattern>
(Application of Resist Composition and Bake after Application)
(Exposure)
(Bake after Exposure)
(Developing Step)
(Rinsing Step)
Hereinafter, the conditions for pattern formation in each example and each comparative example are listed in Table 4.
The formulation of the treatment liquid (the developer or rinsing liquid) listed in Table 4 is listed in Table 5.
The characteristics of the organic solvents used in the treatment liquid (the developer or the rinsing liquid) listed in Table 5 are listed in Tables 6 to 8. Table 6 shows the characteristics of the first organic solvent, Table 7 shows the characteristics of the second organic solvent, and Table 8 shows the characteristics of other organic solvents.
X=(δp)2/((δd)2+(δp)2+(δh)2)×100. Equation (2):
<Evaluation>
(Sensitivity)
(Number of Resolution Frames (Resolution))
(Residues (Property of Suppressing Residues))
(Shape (Property of Suppressing Reduction in Film Thickness))
As shown in the results listed in the table, it was confirmed that in a case where the treatment liquid of the present invention was used as a rinsing liquid, the resolution, the property of suppressing reduction in film thickness, and the property of suppressing residues were excellent.
In a case where at least one of a requirement that the first organic solvent is an organic solvent containing a branched chain alkyl group (an ether-based solvent having 6 to 12 carbon atoms which contains a branched chain alkyl group or an ester-based solvent having 5 to 8 carbon atoms which contains a branched chain alkyl group) or a requirement that the second organic solvent is an organic solvent containing a branched chain alkyl group (an ester-based solvent having 5 to 8 carbon atoms which contains a branched chain alkyl group or a carbonic acid ester-based solvent having 5 to 9 carbon atoms which contains a branched chain alkyl group) is satisfied, it was confirmed that the resolution was more excellent (see Examples 8, 9, and 16 and other examples and comparative examples).
<Pattern Formation>
(Application of Resist Composition and Bake after Application)
(Exposure)
(Bake after Exposure)
(Developing Step)
(Rinsing Step)
<Evaluation>
(Process Margin Evaluation (Resolution and Number of Resolution Frames))
(Residues (Property of Suppressing Residues))
As shown in the above-described evaluation results, it was confirmed that the pattern forming method using the treatment liquid according to the embodiment of the present invention enables formation of an ultrafine size pattern and thus can be suitably used.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-222306 | Dec 2019 | JP | national |
This application is a Continuation of PCT International Application No. PCT/JP2020/043187 filed on Nov. 19, 2020, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2019-222306 filed on Dec. 9, 2019. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2020/043187 | Nov 2020 | US |
| Child | 17833904 | US |
