JP3305293B2 - Pattern formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method, and more particularly, to a method for forming a resist pattern for forming a semiconductor element or a semiconductor integrated circuit on a semiconductor substrate by using exposure light having a wavelength of 1 nm to 180 nm. The present invention relates to a pattern forming method for forming a pattern.

[0002]

2. Description of the Related Art A KrF excimer laser has been put into practical use as exposure light used for forming a resist pattern by performing pattern exposure on a resist film formed on a semiconductor substrate. Devices having a semiconductor element or a semiconductor integrated circuit formed using an exposed resist pattern are appearing on the market.

In this case, as a resist material for pattern exposure by a KrF excimer laser, a material having a phenolic resin is mainly used.

In order to further miniaturize a semiconductor element or a semiconductor integrated circuit, an ArF excimer laser having a shorter wavelength than a KrF excimer laser is used as exposure light. As a resist material for pattern exposure using an ArF excimer laser, a material having an acrylic acid-based resin is mainly studied.

[0005]

SUMMARY OF THE INVENTION However, semiconductor devices
Or to realize further miniaturization of semiconductor integrated circuits
The exposure light has a higher wavelength than the ArF excimer laser.
Short, Xe_TwoLaser light (wavelength: 172 nm band), F
_TwoLaser light (wavelength: 157 nm band), Kr_TwoLaser light
(Wavelength: 146 nm band), ArKr laser light (wavelength: 1
34 nm band), Ar _TwoLaser light (wavelength: 126 nm band)
Or soft X-ray (wavelength: 13 nm band, 11 nm band, or 5 nm
Band) or the like.

Therefore, we have tried to form a resist pattern by performing pattern exposure using a F ₂ laser beam on a resist film made of a conventionally known resist material. Hereinafter, a method of forming a resist pattern using a conventionally known resist material will be described with reference to FIG.
This will be described with reference to (a) to (d).

First, a resist material having the following composition was prepared.

Base resin: poly ((2-methyl-2-adamantyl methacrylate) (30 mol%)-(t-butyl methacrylate) (30 mol%)-(methyl methacrylate) (30 mol%)-(methacrylic acid) (10 mol %)) 2 g Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g

Next, as shown in FIG. 6A, a resist material having the above composition is spin-coated on the semiconductor substrate 1 to form a resist film 2 having a thickness of 0.5 μm.

Next, as shown in FIG. 1B, pattern exposure is performed by irradiating the resist film 2 with an F ₂ laser beam 4 via a mask 3. By doing so, an acid is generated from the acid generator in the exposed portion 2a of the resist film 2, while no acid is generated in the unexposed portion 2b of the resist film 2.

Next, as shown in FIG. 6C, the semiconductor substrate 1 is heated to, for example, 100.degree.
Heating is performed at a temperature of 60 seconds.

Next, the resist film 2 is developed using an alkaline developer, for example, a 2.38 wt% tetramethylammonium hydroxide developer.
A resist pattern was formed.

However, as shown in FIG. 6D, a resist pattern 5 having a defective pattern shape was obtained.

[0014] Thus, the pattern shape of the resist pattern 5 is defective is not limited to the exposure light is the F ₂ laser beam, in the case of exposure light having a wavelength of 1nm band ~180nm band, It was similar.

[0015] In view of the above, the present invention provides 1n
It is an object of the present invention to obtain a good pattern shape when a resist pattern is formed by performing pattern exposure using light in the m band to 180 nm band.

[0016]

The inventors of the present invention consider that the reason why the pattern shape of the resist pattern becomes defective is that the resist film has a high absorbency to light in the 1 nm to 180 nm band, and the 1 nm band is considered to be high. As a result of conducting various studies on measures for lowering the absorption of light in the wavelength range of ~ 180 nm, the resist material was found to contain halogen atoms, cyano groups, nitro groups, alkoxy groups, amino groups, alkyl groups,
When including a trifluoromethyl group or a mercapto group,
It has been found that the resist film has low absorbance for exposure light in the 1 nm to 180 nm band.

Therefore, a halogen atom,
When the cyano group, the nitro group, the alkoxy group, the amino group, the alkyl group, the trifluoromethyl group or the mercapto group is included, as a result of examining the reason why the absorbability of the resist material to exposure light in the 1 nm band to 180 nm band is reduced,
These atoms or groups have the property of shifting the peak of the absorption wavelength of the exposure light originally possessed by the resist material to longer wavelengths, or reducing the absorbency of the resist material for exposure light in the short wavelength band. It was found to have.

Hereinafter, a verification example in which the peak of the absorption wavelength of exposure light shifts to the longer wavelength side when the base resin of the resist material contains an amino group will be described with reference to FIG.

FIG. 1 is a diagram for explaining that when the aromatic ring of polyvinylphenol is substituted with an amino group, the absorption band of exposure light shifts. In FIG. 1, the broken line indicates that the aromatic ring is an amino group. The absorption wavelength of unsubstituted polyvinylphenol is shown, and the solid line shows the absorption wavelength of an o, o-2 substituted product in which the aromatic ring of polyvinylphenol is substituted with an amino group. As can be seen from FIG. 1, the peak of the absorption wavelength which was in the 190 nm band when not substituted with an amino group was shifted to a longer wavelength side when substituted with an amino group.
It is shifted by about 0 nm.

The peak of the absorption wavelength band of the resist film is 190
In the case of the nm band, transparency to F ₂ laser light having a wavelength of the 157 nm band is not good, but when the peak of the absorption wavelength band shifts from the 190 nm band to the longer wavelength side of about 30 nm,
Transparency to F ₂ laser beam is improved.

Japanese Patent Application Laid-Open No. Sho 60-254401 also discloses a resist material in which a base resin contains fluorine which is one of halogen atoms. This resist material contains α-trifluoromethylacrylic acid and an ester of an alcohol having an electron-withdrawing group as one repeating unit in a resin. In this case, the resist material with respect to the electron beam It is shown that sensitivity is improved.

However, Japanese Patent Application Laid-Open No. Sho 60-254401
Japanese Patent Application Laid-Open No. H10-20795 uses an electron beam as the exposure light, whereas the present invention uses light having a wavelength in the range of 1 nm to 180 nm as the exposure light. Japanese Patent Application Laid-Open No. 60-254041 discloses a method in which a halogen atom is included in a base resin for the purpose of improving the sensitivity to an electron beam. Since the base resin contains, for example, a halogen atom for the purpose of improving the transparency to exposure light having the above, the two are completely different in the technical idea.

Specifically, the pattern forming method according to the present invention is selected from the group consisting of a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group and a mercapto group. At least one
A resist film forming step of applying a resist material containing two atoms or groups on a substrate to form a resist film, and performing a pattern exposure by irradiating the resist film with exposure light having a wavelength of 1 nm to 180 nm. And a pattern forming step of developing the pattern-exposed resist film to form a resist pattern.

According to the pattern forming method of the present invention, the resist material contains a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group or a mercapto group. Since the absorption wavelength range of the exposure light shifts to the longer wavelength side or the absorbability of the resist film with respect to the exposure light in the shorter wavelength range is reduced, the wavelength range of the light having a wavelength of 1 nm to 180 nm is reduced. Can be reduced. For this reason, the transparency to exposure light having a wavelength in the range of 1 nm to 180 nm can be increased, so that 1
When pattern exposure is performed using light in the nm band to 180 nm band, a resist pattern having a favorable pattern shape can be formed.

In the pattern forming method of the present invention, the atoms or groups are bonded to the main chain of the base resin of the resist material, the side chains of the base resin, the heterocycle of the base resin, or the carbon constituting the double bond of the base resin. Is preferred.

In the pattern forming method of the present invention, the atoms or groups are preferably halogen atoms bonded to an ester portion of an acrylic resin serving as a base resin of the resist material.

In the pattern forming method of the present invention, the resist material is preferably a chemically amplified resist.

When the resist material is a chemically amplified resist, the atoms or groups are preferably contained in an acid leaving group, a crosslinking agent or a dissolution inhibitor of the base resin.

In the pattern forming method of the present invention, the base resin preferably contains a polyvinyl phenol, a polyvinyl alcohol, an acrylic resin, a novolak resin or a derivative thereof, in which a hydrogen atom has been replaced by a fluorine atom.

According to the pattern forming method of the present invention, a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoro group, It is preferable that the method further includes a step of forming a water-soluble resin film made of a water-soluble resin containing a methyl group or a mercapto group.

In this case, the water-soluble resin is preferably polyacrylic acid, polyvinyl alcohol, polyvinyl pyrrolidone or polystyrene sulfonic acid.

According to the pattern forming method of the present invention, between a resist film forming step and a pattern forming step, a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoro group, It is preferable that the method further includes a step of forming a water-soluble resin film composed of a compound containing a methyl group or a mercapto group and a water-soluble resin.

In this case, the compound is trifluoroacetic acid,
Preference is given to trifluoromethylsulfonic acid or a fluorinated surfactant.

In this case, the water-soluble resin is preferably polyacrylic acid, polyvinyl alcohol, polyvinylpyrrolidone or polystyrenesulfonic acid.

In the pattern forming method of the present invention, the exposure light is preferably F ₂ laser light or Ar ₂ laser light.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) In a pattern forming method according to a first embodiment, a part of a hydrogen atom bonded to a benzene ring of polyvinyl phenol is used as a base resin of a resist material. A compound substituted with an atom is used. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly (o, o-difluoro-p-hydroxystyrene-co-p- (t-butoxy) o, o-difluorostyrene) 1 g Acid generator: bis (dicyclohexylsulfonyl) diazomethane 0.01 g Solvent ： Propylene glycol monoethyl ether acetate 4g

First, as shown in FIG. 2A, a resist material having the above composition is spin-coated on a semiconductor substrate 10 to form a resist film 11 having a thickness of 0.3 μm.

Next, as shown in FIG. 2B, pattern exposure is performed by irradiating the resist film 11 with an F ₂ laser beam 13 having a wavelength of 157 nm through a mask 12. By doing so, the exposed portions 11 of the resist film 11
In a, acid is generated from the acid generator, while no acid is generated in the unexposed portion 11b of the resist film 11.

Next, as shown in FIG. 2C, the semiconductor substrate 10 and thus the resist film 11 are heated. The base resin is hardly soluble in alkali, but decomposes when heated in the presence of an acid.
a becomes soluble in an aqueous alkaline solution.

Next, the resist film 11 is subjected to a development process using an alkaline developing solution.
Since the exposed portions 11a are dissolved in the developing solution, a resist pattern 14 composed of the unexposed portions 11b of the resist film 11 is obtained as shown in FIG.

According to the first embodiment, the base resin is
Since a part of the hydrogen atoms bonded to the benzene ring is replaced with a fluorine atom, the peak of the absorption wavelength of light determined by the benzene ring shifts to a longer wavelength side, and thus has a wavelength of 1 nm to 180 nm. Light absorption is reduced. For this reason, the transparency to exposure light having a wavelength of 1 nm to 180 nm increases, and the exposure light sufficiently reaches the bottom of the resist film 11.
A resist pattern having a line width of m and a good cross-sectional shape was obtained.

(First Modification of First Embodiment) The first modification of the first embodiment is different from the first embodiment only in the resist material. Only materials will be described. That is, a resin obtained by partially replacing a hydrogen atom bonded to a benzene ring of polyvinylphenol with a chlorine atom is used as the base resin of the resist material.

Base resin: poly (o, o-dichloro-p-hydroxystyrene-co-p- (t-butoxy) o, o-dichlorostyrene) 1 g Acid generator: bis (dicyclohexylsulfonyl) diazomethane 0.01 g Solvent ： Propylene glycol monoethyl ether acetate 4g

(Second Modification of First Embodiment) The second modification of the first embodiment differs from the first embodiment only in the resist material. Only materials will be described. That is, a resin obtained by partially replacing a hydrogen atom bonded to a benzene ring of polyvinylphenol with a chlorine atom is used as the base resin of the resist material.

Base resin: poly (m, m-dichloro-p-hydroxystyrene-co-p- (t-butoxy) m, m-dichlorostyrene) 1 g Acid generator: bis (dicyclohexylsulfonyl) diazomethane 0.01 g Solvent ： Propylene glycol monoethyl ether acetate 4g

(Second Embodiment) In the pattern forming method according to the second embodiment, as a base resin of a resist material, a part of hydrogen atoms bonded to the polymer main chain of polyvinyl phenol is replaced with fluorine atoms. Use what was done. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly (p- (2,2-difluorovinyl) phenol-co-p- (1-ethoxyethoxy) -2,2-difluorostyrene) 1 g Acid generator: bis (dicyclohexylsulfonyl) diazomethane 0 .01g Solvent: ethyl ethoxypropionate 4g

First, as shown in FIG. 2A, a resist material having the above-described composition is spin-coated on a semiconductor substrate 10 to form a resist film 11, and as shown in FIG. The resist film 11 is irradiated with F ₂ laser light 13 having a wavelength in the 157 nm band via a mask 12 to perform pattern exposure. In this way, acid is generated from the acid generator in the exposed portion 11a of the resist film 11, while no acid is generated in the unexposed portion 11b of the resist film 11.

Next, as shown in FIG. 2C, when the semiconductor substrate 10 is heated, the base resin is hardly soluble in alkali, but is decomposed by heating in the presence of an acid. The exposed portion 11a becomes soluble in an aqueous alkaline solution.

Next, the resist film 11 is subjected to a developing process using an alkaline developing solution.
Since the exposed portions 11a are dissolved in the developing solution, a resist pattern 14 composed of the unexposed portions 11b of the resist film 11 is obtained as shown in FIG.

According to the second embodiment, the base resin is
Since a part of the hydrogen atoms bonded to the polymer main chain is replaced by a fluorine atom, the absorptivity for light in a short wavelength range is reduced, so that the absorptivity for light having a wavelength of 1 nm to 180 nm is reduced. Become smaller. For this reason, the 1 nm band
Since the transparency to the exposure light having a wavelength in the 180 nm band is increased, the exposure light sufficiently reaches the bottom of the resist film 11. I got it.

(Modification of Second Embodiment) The modification of the second embodiment is different from the second embodiment only in the resist material. Therefore, only the resist material will be described below. I do. That is, a resin obtained by partially replacing a hydrogen atom bonded to the polymer main chain of polyvinyl phenol with a trifluoromethyl group is used as the base resin of the resist material.

Base resin: poly (p- (α-trifluoromethylvinyl) phenol-co-p- (1-ethoxyethoxy) -α-trifluoromethylstyrene) 1 g Acid generator: bis (dicyclohexylsulfonyl) diazomethane 0.01 g Solvent: 4 g of ethyl ethoxypropionate

(Third Embodiment) In the pattern forming method according to the third embodiment, a part of a hydrogen atom bonded to a polymer main chain of polyvinyl phenol and a benzene ring are used as a base resin of a resist material. Used are those in which some of the hydrogen atoms are replaced by fluorine atoms. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly (p-hydroxyheptafluorostyrene-co-p- (t-butoxy) -heptafluorostyrene) 1 g Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethylethoxypropionate 4g

First, as shown in FIG. 2A, a resist material having the above-described composition is spin-coated on a semiconductor substrate 10 to form a resist film 11, and as shown in FIG. The resist film 11 is irradiated with F ₂ laser light 13 having a wavelength in the 157 nm band via a mask 12 to perform pattern exposure. In this way, acid is generated from the acid generator in the exposed portion 11a of the resist film 11, while no acid is generated in the unexposed portion 11b of the resist film 11.

Next, as shown in FIG. 2C, when the semiconductor substrate 10 is heated, the base resin is hardly soluble in alkali, but is decomposed by heating in the presence of an acid. The exposed portion 11a becomes soluble in an aqueous alkaline solution.

Next, the resist film 11 is subjected to a development process using an alkaline developing solution.
Since the exposed portions 11a are dissolved in the developing solution, a resist pattern 14 composed of the unexposed portions 11b of the resist film 11 is obtained as shown in FIG.

According to the third embodiment, the base resin is
Since some of the hydrogen atoms bonded to the polymer main chain and the benzene ring are substituted with fluorine atoms, the absorption of light in the short wavelength range is reduced, and the peak of the absorption wavelength of light determined by the benzene ring is reduced. Shifts to the longer wavelength side, so that the absorbency for light having a wavelength in the range of 1 nm to 180 nm decreases. Therefore, 1 nm band to 180
Since the transparency to the exposure light having a wavelength in the nm band is increased, the exposure light sufficiently reaches the bottom of the resist film 11. I got it.

(Modification of Third Embodiment) A modification of the third embodiment is different from the third embodiment only in the resist material. Therefore, only the resist material will be described below. I do. That is, as the base resin of the resist material, one obtained by substituting a part of the hydrogen atoms bonded to the polymer main chain of polyvinylphenol and a part of the hydrogen atoms bonded to the benzene ring with an alkyl group, for example, a methyl group, respectively. Used.

Base resin: poly (p-hydroxy-α-methyl-o-methylstyrene-co-p- (t-butoxy) -α-methyl-o-methylstyrene) 1 g Acid generator: triphenylsulfonium trif Rate 0.01 g Solvent: Ethyl ethoxypropionate 4 g

(Fourth Embodiment) In a pattern forming method according to a fourth embodiment, a part of hydrogen atoms bonded to a polymer main chain of an acrylic resin is replaced with fluorine atoms as a base resin of a resist material. Use what was done. Less than,
The composition of the resist material will be specifically described.

Base resin: poly (α-fluoroacrylic acid-co-α-fluoroacrylic acid tetrahydropyranyl-co-α-fluoroacrylic acid norbornyl) 1 g Acid generator: triphenylsulfonium triflate 0.01 g Solvent ： Propylene glycol monoethyl ether acetate 4g

First, as shown in FIG. 2A, a resist material having the above composition is spin-coated on a semiconductor substrate 10 to form a resist film 11, and then, as shown in FIG. The resist film 11 is irradiated with F ₂ laser light 13 having a wavelength in the 157 nm band via a mask 12 to perform pattern exposure. In this way, acid is generated from the acid generator in the exposed portion 11a of the resist film 11, while no acid is generated in the unexposed portion 11b of the resist film 11.

Next, as shown in FIG. 2C, when the semiconductor substrate 10 is heated, the base resin is hardly soluble in alkali, but is decomposed by heating in the presence of an acid. The exposed portion 11a becomes soluble in an aqueous alkaline solution.

Next, the resist film 11 is subjected to a development process using an alkaline developing solution.
Since the exposed portions 11a are dissolved in the developing solution, a resist pattern 14 composed of the unexposed portions 11b of the resist film 11 is obtained as shown in FIG.

According to the fourth embodiment, the base resin is
Since a part of the hydrogen atoms bonded to the polymer main chain is replaced by a fluorine atom, the absorptivity for light in a short wavelength range is reduced, so that the absorptivity for light having a wavelength of 1 nm to 180 nm is reduced. Become smaller. For this reason, the 1 nm band
Since the transparency to the exposure light having a wavelength in the 180 nm band is increased, the exposure light sufficiently reaches the bottom of the resist film 11. I got it.

(Modification of Fourth Embodiment) The modification of the fourth embodiment differs from the fourth embodiment only in the resist material, and therefore, only the resist material will be described below. I do. In other words, as a base resin of the resist material, some of the hydrogen atoms bonded to the polymer main chain of the acrylic resin are replaced with chlorine atoms, and the nitro group is contained in the acid leaving group of the heterocycle of the acrylic resin. Use those that have been used.

Base resin: poly (α-chloroacrylic acid-co-α-chloroacrylic acid-3-nitrotetrahydropyranyl-co-α-chloroacrylic acid norbornyl) 1 g Acid generator: triphenylsulfonium triflate 0 .01g Solvent: propylene glycol monoethyl ether acetate 4g

(Fifth Embodiment) In a pattern forming method according to a fifth embodiment, a part of a hydrogen atom bonded to a polymer main chain of polyvinyl alcohol is replaced with a fluorine atom as a base resin of a resist material. Use what was done. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly (1,2-difluoro-1-hydroxyethylene-co-1,2-difluoro-1-t-butoxyethylene) 1 g Acid generator: 0.01 g of diphenyliodonium triflate Solvent: ethyl ethoxy Propionate 4g

First, as shown in FIG. 2A, a resist material having the above-mentioned composition is spin-coated on a semiconductor substrate 10 to form a resist film 11, and as shown in FIG. The resist film 11 is irradiated with F ₂ laser light 13 having a wavelength in the 157 nm band via a mask 12 to perform pattern exposure. In this way, acid is generated from the acid generator in the exposed portion 11a of the resist film 11, while no acid is generated in the unexposed portion 11b of the resist film 11.

Next, as shown in FIG. 2C, when the semiconductor substrate 10 is heated, the base resin is hardly soluble in alkali, but is decomposed by heating in the presence of an acid. The exposed portion 11a becomes soluble in an aqueous alkaline solution.

Next, the resist film 11 is subjected to a development process using an alkaline developing solution.
Since the exposed portions 11a are dissolved in the developing solution, a resist pattern 14 composed of the unexposed portions 11b of the resist film 11 is obtained as shown in FIG.

According to the fifth embodiment, the base resin is
Since a part of the hydrogen atoms bonded to the polymer main chain is replaced by a fluorine atom, the absorptivity for light in a short wavelength range is reduced, so that the absorptivity for light having a wavelength of 1 nm to 180 nm is reduced. Become smaller. For this reason, the 1 nm band
Since the transparency to the exposure light having a wavelength in the 180 nm band is increased, the exposure light sufficiently reaches the bottom of the resist film 11. I got it.

(Sixth Embodiment) In the pattern forming method according to the sixth embodiment, the resist material is such that the base resin contains an alkyl group such as a methyl group and the hydrogen atom bonded to the side chain of the base resin. In particular, an acrylic resin in which a hydrogen atom in an ester portion is replaced with a fluorine atom is used. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly ((2-methyl-2-adamantyl methacrylate) (30 mol%)-(tri (trifluoromethyl) methyl methacrylate) (30 mol%)-(methyl methacrylate) (30 mol%)- (Methacrylic acid) (10 mol%)) 2 g Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g

First, as shown in FIG. 2A, a resist material having the above-described composition is spin-coated on a semiconductor substrate 10 to form a resist film 11, and then, as shown in FIG. The resist film 11 is irradiated with F ₂ laser light 13 having a wavelength in the 157 nm band via a mask 12 to perform pattern exposure. In this way, acid is generated from the acid generator in the exposed portion 11a of the resist film 11, while no acid is generated in the unexposed portion 11b of the resist film 11.

Next, as shown in FIG. 2C, when the semiconductor substrate 10 is heated, the base resin is hardly soluble in alkali, but is decomposed by heating in the presence of an acid. The exposed portion 11a becomes soluble in an aqueous alkaline solution.

Next, when the resist film 11 is subjected to a developing process using an alkaline developing solution, for example, a 2.38 wt% tetramethylammonium hydroxide developing solution, the exposed portions 11a of the resist film 11 are changed to the developing solution. As a result, the resist pattern 14 including the unexposed portions 11b of the resist film 11 is obtained as shown in FIG.

According to the sixth embodiment, since the base resin contains a methyl group and the hydrogen atoms in the side chains of the base resin are substituted with fluorine atoms, the absorption of light in a short wavelength range is reduced. In addition, absorptivity to light having a wavelength of 1 nm to 180 nm is reduced. Therefore, 1n
Since the transparency to exposure light having a wavelength of the m band to 180 nm band is increased, the exposure light sufficiently reaches the bottom of the resist film 11 and thus has a line width of 0.07 μm and a good cross-sectional shape. A resist pattern was obtained.

(First Modification of Sixth Embodiment) The first modification of the sixth embodiment differs from the sixth embodiment only in the resist material. Only materials will be described. That is, as the base resin of the resist material, one in which hydrogen atoms bonded to side chains of the base resin, particularly hydrogen atoms in the ester portion of the acrylic resin, are substituted with fluorine atoms is used. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly (2,2,2-trifluoroethyl methacrylate) 2 g (chemical formula is shown in Chemical Formula 1) Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g

[0085]

Embedded image

(Second Modification of Sixth Embodiment) The second modification of the sixth embodiment differs from the sixth embodiment only in the resist material. Only materials will be described. That is, as the base resin of the resist material, one in which hydrogen atoms bonded to side chains of the base resin, particularly hydrogen atoms in the ester portion of the acrylic resin, are substituted with fluorine atoms is used. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly (1,1,1,3,3,3-hexafluoroisopropyl methacrylate) 2 g (chemical formula is represented by Chemical Formula 2) Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20g

[0088]

Embedded image

FIG. 7 shows the exposure light when a resist film having a thickness of 0.1 μm is formed using the resist material according to the first and second modifications of the sixth embodiment and the conventional example. The relationship between wavelength and transmittance is shown.

FIG. 7 shows that the first and second embodiments of the sixth embodiment
According to the modified example, it can be seen that a transmittance of 40% or more can be obtained for a wavelength (F ₂ laser light) in the 157 nm band. According to the conventional example, the wavelength of the 157 nm band (F ₂
The transmittance for laser light) is about 20%.

(Seventh Embodiment) In the pattern forming method according to the seventh embodiment, the base resin contains an alkyl group such as a methyl group as a resist material, and the hydrogen atom in the acid leaving group of the base resin is reduced. Use those substituted with fluorine atoms. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly ((2,2,2-trifluoroethyl methacrylate)-(2-methyl-2-adamantyl methacrylate)) 2 g (chemical formula is shown in Chemical Formula 3) Acid generator: triphenyl sulfo Nitrite triflate 0.4 g Solvent: diglyme 20 g

[0093]

Embedded image

First, as shown in FIG. 2A, a resist material having the above composition is spin-coated on the semiconductor substrate 10 to form a resist film 11, and then, as shown in FIG. The resist film 11 is irradiated with F ₂ laser light 13 having a wavelength in the 157 nm band via a mask 12 to perform pattern exposure. In this way, acid is generated from the acid generator in the exposed portion 11a of the resist film 11, while no acid is generated in the unexposed portion 11b of the resist film 11.

Next, as shown in FIG. 2C, when the semiconductor substrate 10 is heated, the base resin is hardly soluble in alkali, but is decomposed by heating in the presence of an acid. The exposed portion 11a becomes soluble in an aqueous alkaline solution.

Next, when the resist film 11 is subjected to a developing process using an alkaline developing solution, for example, a 2.38 wt% tetramethylammonium hydroxide developing solution, the exposed portion 11a of the resist film 11 is changed to the developing solution. As a result, the resist pattern 14 including the unexposed portions 11b of the resist film 11 is obtained as shown in FIG.

According to the seventh embodiment, since the base resin contains a methyl group and the hydrogen atom in the acid leaving group of the base resin is replaced with a fluorine atom, the light absorbing property for light in a short wavelength range is reduced. Therefore, absorptivity to light having a wavelength in the range of 1 nm to 180 nm is reduced. For this reason, the transparency to exposure light having a wavelength of 1 nm to 180 nm is increased, and the exposure light sufficiently reaches the bottom of the resist film 11, so that a good cross section having a line width of 0.07 μm is obtained. A resist pattern having a shape was obtained.

[0098]

The acid leaving group of the base resin in the seventh embodiment was substituted by a halogen atom, cyano group, nitro group, alkoxy group, amino group, alkyl group, trifluoromethyl group or mercapto group. , A t-butyl group, a 1-ethoxyethyl group, a t-butyloxycarbonyl group, and the like.

(Eighth Embodiment) In a pattern forming method according to an eighth embodiment, a hydrogen atom bonded to a benzene ring of polyvinyl phenol is partially replaced with a fluorine atom as a base resin of a resist material. As the dissolution inhibitor, one obtained by substituting a part of the hydrogen atoms bonded to the benzene ring with a fluorine atom is used.
Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly (o, o-difluoro-p-hydroxystyrene-co-o, o-difluoro-p-trifluoromethoxystyrene) 1 g Dissolution inhibitor: bis (p- (t-butoxycarbonyloxy) -M, m-difluorophenyl) methane 0.4 g Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethyl ethoxypropionate 4 g

First, as shown in FIG. 2A, a resist material having the above-described composition is spin-coated on a semiconductor substrate 10 to form a resist film 11, and then, as shown in FIG. The resist film 11 is irradiated with F ₂ laser light 13 having a wavelength in the 157 nm band via a mask 12 to perform pattern exposure. In this way, acid is generated from the acid generator in the exposed portion 11a of the resist film 11, while no acid is generated in the unexposed portion 11b of the resist film 11.

The base resin is alkali-soluble, but the resist film 11 is hardly soluble in alkali due to the action of the dissolution inhibitor. Therefore, as shown in FIG.
When the semiconductor substrate 10 is heated, the dissolution inhibitor is heated in the presence of an acid, so that the dissolution inhibitor is decomposed, so that the exposed portions 11a of the resist film 11 become soluble in an alkaline aqueous solution.

Next, the resist film 11 is subjected to a development process using an alkaline developing solution.
Since the exposed portions 11a are dissolved in the developing solution, a resist pattern 14 composed of the unexposed portions 11b of the resist film 11 is obtained as shown in FIG.

According to the eighth embodiment, since the base resin and the dissolution inhibitor have part of the hydrogen atoms bonded to the benzene ring replaced by fluorine atoms, the absorption wavelength of light determined by the benzene ring is lower than that of the benzene ring. Since the peak shifts to the longer wavelength side, the absorption for light having a wavelength in the range of 1 nm to 180 nm is reduced. Therefore, 1 nm band to 180 nm
Since the transparency to the exposure light having the band wavelength increases,
Since the exposure light sufficiently reached the bottom of the resist film 11, a resist pattern having a line width of 0.1 μm and a good sectional shape could be obtained.

(Modification of Eighth Embodiment) The modification of the eighth embodiment differs from the eighth embodiment only in the resist material, and therefore, only the resist material will be described below. I do. That is, as the base resin of the resist material, a resin in which a part of hydrogen atoms bonded to the benzene ring of polyvinylphenol is substituted with an amino group is used, and a resin containing a cyano group is used as a dissolution inhibitor. .

Base resin: poly (o-amino-p-hydroxystyrene-co-o-amino-p-methoxystyrene) 1 g Dissolution inhibitor: bis (p- (t-butoxy) -m-cyanophenyl) methane 0 Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethyl ethoxypropionate 4 g

(Ninth Embodiment) The pattern forming method according to the ninth embodiment uses, as a base resin of a resist material, one in which an amino group is bonded to carbon forming a double bond. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly ((1-vinyloxy) 3-amino-2-cyclohexene-co-vinyloxyethoxyethane) 1 g Acid generator: 0.01 g of trimethylsulfonium triflate Solvent: propylene glycol monoethyl ether acetate 4g First, as shown in FIG. 2A, a resist material having the above composition is spin-coated on the semiconductor substrate 10 to form a resist film 11, and then, as shown in FIG. 11 through the mask 12 to 157 nm
Pattern exposure is performed by irradiating F ₂ laser light 13 having a band wavelength. In this way, acid is generated from the acid generator in the exposed portion 11a of the resist film 11, while no acid is generated in the unexposed portion 11b of the resist film 11.

Next, as shown in FIG. 2C, when the semiconductor substrate 10 is heated, the base resin is hardly soluble in alkali, but is decomposed by heating in the presence of an acid. The exposed portion 11a becomes soluble in an aqueous alkaline solution.

Next, the resist film 11 is subjected to a development process using an alkaline developing solution.
Since the exposed portions 11a are dissolved in the developing solution, a resist pattern 14 composed of the unexposed portions 11b of the resist film 11 is obtained as shown in FIG.

According to the ninth embodiment, the base resin is
Since the amino group is bonded to the carbon constituting the double bond, the absorptivity to light in a short wavelength range is reduced.
The absorptivity to light having a wavelength in the m band to 180 nm band is reduced. For this reason, transparency to exposure light having a wavelength in the range of 1 nm to 180 nm increases, and the exposure light sufficiently reaches the bottom of the resist film 11.
A resist pattern having a line width of μm and a good cross-sectional shape was obtained.

(Tenth Embodiment) In a pattern forming method according to a tenth embodiment, a part of a hydrogen atom bonded to a benzene ring of polyvinyl phenol is replaced with a fluorine atom as a base resin of a resist material. Use something. Hereinafter, the composition of the resist material will be specifically described. In the first to ninth embodiments, a positive resist pattern is formed. In the tenth embodiment, a negative resist pattern is formed.

Base resin: 1 g of poly (o, o-difluoro-p-hydroxystyrene-co-o, o-difluoro-p-trifluoromethoxystyrene) Crosslinking agent: 2,4,6-tri (N, N- Diethoxymethylamino) -1,3,5-triazine 0.3 g Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethyl lactate 4 g

First, as shown in FIG. 3A, a resist material having the above-described composition is spin-coated on a semiconductor substrate 20 to form a resist film 21. Then, as shown in FIG. through a mask 22 with respect to the resist film 21, performing pattern exposure by irradiating F ₂ laser beam 23 with a wavelength of 157nm band. In this way, acid is generated from the acid generator in the exposed portion 21a of the resist film 21, while no acid is generated in the unexposed portion 21b of the resist film 21.

Next, as shown in FIG. 3C, the semiconductor substrate 20 is heated. The base resin is soluble in an aqueous alkali solution, but when heated in the presence of an acid, a crosslinking reaction occurs due to the action of a crosslinking agent.
The exposed portion 21a changes to hardly soluble in alkali.

Next, the resist film 21 is subjected to a development process using an alkaline developing solution.
Since the unexposed portion 21a is dissolved in the developing solution,
As shown in (2), a resist pattern 24 composed of the exposed portions 21b of the resist film 21 is obtained.

According to the tenth embodiment, since the base resin has a structure in which a part of the hydrogen atoms bonded to the benzene ring of polyvinylphenol is replaced with a fluorine atom, the peak of the light absorption wavelength determined by the benzene ring is determined. Shifts to the longer wavelength side, so that the absorbance for light having a wavelength in the 1 nm to 180 nm band is reduced. For this reason, the transparency to exposure light having a wavelength in the range of 1 nm to 180 nm increases, so that the exposure light sufficiently reaches the bottom of the resist film 21 and has a line width of 0.1 μm and a good cross section. A resist pattern having a shape was obtained.

(Modification of Tenth Embodiment) The modification of the tenth embodiment is different from the tenth embodiment only in the resist material. Therefore, only the resist material will be described below. I do. That is, as the base resin of the resist material, a resin in which a part of hydrogen atoms bonded to the benzene ring of polyvinylphenol is substituted with a mercapto group is used, and a resin containing an alkoxy group is used as a crosslinking agent.

Base resin: poly (p-hydroxystyrene-co-o-mercapto-p-methoxystyrene) 1 g Crosslinking agent: 1,3-dimethoxy-1,2,3-pentanetriol triglycidyl ether 0.3 g acid Generator: triphenylsulfonium triflate 0.01 g Solvent: ethyl lactate 4 g

(Eleventh Embodiment) In a pattern forming method according to an eleventh embodiment, a base resin of a resist material contains a fluorine atom, and a water-soluble resin film containing a fluorine atom is formed on the resist film. It accumulates. still,
The eleventh embodiment is a case where a positive resist pattern is formed. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly ((2-methyl-2-adamantyl methacrylate) (30 mol%)-(tri (trifluoromethyl) methyl methacrylate) (30 mol%)-(methyl methacrylate) (30 mol%)- (Methacrylic acid) (10 mol%)) 2 g Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g

First, as shown in FIG. 4A, a resist material having the above composition is spin-coated on a semiconductor substrate 30 to form a resist film 3 having a thickness of, for example, 0.5 μm.
After forming 1, a water-soluble resin film 32 made of a water-soluble resin containing a fluorine atom is deposited on the resist film 31 as shown in FIG.

As the water-soluble resin, all or a part of hydrogen atoms such as polyacrylic acid, polyvinyl alcohol, polyvinylpyrrolidone or polystyrene sulfonic acid may be halogen atoms such as fluorine atoms, cyano groups, nitro groups or alkoxy groups. , An amino group, an alkyl group, a trifluoromethyl group or a mercapto group, or a polymer represented by the following chemical formula 4, but is not limited thereto.

[0125]

Embedded image

Next, as shown in FIG. 4C, pattern exposure is performed by irradiating the resist film 31 with an F ₂ laser beam 34 having a wavelength of 157 nm through a mask 33. By doing so, the exposed portion 31 of the resist film 31
In a, acid is generated from the acid generator, while no acid is generated in the unexposed portion 31b of the resist film 31.

Next, as shown in FIG. 4D, when the semiconductor substrate 30 is heated, the base resin is hardly soluble in alkali, but is decomposed by heating in the presence of an acid. The exposed portion 31a becomes soluble in an aqueous alkaline solution.

Next, using a 2.38 wt% tetramethylammonium hydroxide developer, the water-soluble resin film 32 is removed and the resist film 31 is developed.
As shown in FIG. 4E, the unexposed portion 3 of the resist film 31
A resist pattern 35 of 1b is obtained.

According to the eleventh embodiment, since both the base resin of the resist material and the water-soluble resin film 32 contain fluorine atoms, the exposure light surely reaches the bottom of the resist film 31. A resist pattern 35 having a good pattern shape can be formed.

(Twelfth Embodiment) In a pattern forming method according to a twelfth embodiment, a base resin of a resist material contains a fluorine atom and a compound containing a fluorine atom and a water-soluble compound are formed on a resist film. This is for depositing a water-soluble resin film made of resin. Note that the twelfth embodiment also
This is a case where a positive resist pattern is formed. Hereinafter, the composition of the resist material will be specifically described.

Base resin: poly ((2-methyl-2-adamantyl methacrylate) (30 mol%)-(tri (trifluoromethyl) methyl methacrylate) (30 mol%)-(methyl methacrylate) (30 mol%)- (Methacrylic acid) (10 mol%)) 2 g Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g

First, as shown in FIG. 4A, a resist material having the above composition is spin-coated on a semiconductor substrate 30 to form a resist film 3 having a thickness of, for example, 0.5 μm.
After forming 1, a water-soluble resin film 32 made of a compound containing a fluorine atom and a water-soluble resin is deposited on the resist film 31 as shown in FIG.

Examples of the compound containing a fluorine atom include, but are not limited to, trifluoroacetic acid, trifluoromethylsulfonic acid, and a fluorine-based surfactant.

Examples of the water-soluble resin include, but are not limited to, polyacrylic acid, polyvinyl alcohol, polyvinyl pyrrolidone, and polystyrene sulfonic acid.

Next, as shown in FIG. 4C, pattern exposure is performed by irradiating the resist film 31 with an F ₂ laser beam 34 having a wavelength of 157 nm through a mask 33. By doing so, the exposed portion 31 of the resist film 31
In a, acid is generated from the acid generator, while no acid is generated in the unexposed portion 31b of the resist film 31.

In this case, since the water-soluble resin film 32 contains fluorine atoms, the water-soluble resin film 32 guides only light having high light intensity to the resist film 31.

Next, as shown in FIG. 4D, when the semiconductor substrate 30 is heated, the base resin is hardly soluble in alkali, but is decomposed by heating in the presence of an acid. The exposed portion 31a becomes soluble in an aqueous alkaline solution.

Next, using a 2.38 wt% tetramethylammonium hydroxide developing solution, the water-soluble resin film 32 is removed and the resist film 31 is developed.
As shown in FIG. 4E, the unexposed portion 3 of the resist film 31
A resist pattern 35 of 1b is obtained.

According to the twelfth embodiment, since the fluorine atoms are contained in both the base resin of the resist material and the water-soluble resin film 32, the exposure light surely reaches the bottom of the resist film 31. A resist pattern 35 having a good pattern shape can be formed.

[0140]

[0141]

[0142]

[0143]

[0144]

[0145] In the first to twelfth embodiments or variations of these described above, as the exposure light, is used an F ₂ laser beam having a wavelength of 157nm band, instead of this,
Xe ₂ laser light (wavelength: 172 nm band), Kr ₂ laser light (wavelength: 146 nm band), ArKr laser light (wavelength:
134 nm band), Ar ₂ laser light (wavelength: 126 nm)
Band) or soft X-rays (wavelength: 13 nm band, 11 nm band or 5)
The same effect can be obtained by using (nm band) or the like.

The acid generator in the first to twelfth embodiments or the modified examples thereof includes onium salts such as sulfonium salts and iodonium salts, sulfonic acid esters, diazodisulfonylmethanes and ketosulfone compounds. Etc. can be used as appropriate.

In the first to twelfth embodiments or their modifications, the resist material may be
If necessary, a basic compound such as an amine or an additive such as a surfactant may be contained.

[0148]

According to the pattern forming method of the present invention, 1
Since the transparency to exposure light having a wavelength in the range of nm to 180 nm can be increased, a resist pattern having a good pattern shape is used when pattern exposure is performed using light in the range of 1 nm to 180 nm as exposure light. Can be formed.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view showing a solution principle of the present invention, and is a view for explaining that when an aromatic ring of polyvinyl phenol is substituted with an amino group, a light absorption band shifts.

FIGS. 2A to 2D are cross-sectional views illustrating respective steps of a pattern forming method according to first to eighth embodiments of the present invention.

FIGS. 3A to 3D are cross-sectional views illustrating respective steps of a pattern forming method according to a ninth embodiment of the present invention.

FIGS. 4A to 4E show the tenth or eleventh embodiments of the present invention.
FIG. 9 is a cross-sectional view showing each step of the pattern forming method according to the embodiment.

FIGS. 5A to 5C are cross-sectional views illustrating respective steps of a pattern forming method according to a twelfth embodiment of the present invention.

FIGS. 6A to 6D are cross-sectional views showing respective steps of a pattern forming method which is a premise of the present invention.

FIG. 7 shows a first modification and a second modification of the sixth embodiment of the present invention.
0.1% by using the resist material according to the modified example and the conventional example.
FIG. 4 is a diagram showing the relationship between the wavelength of exposure light and the transmittance when a resist film having a thickness of μm is formed.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 semiconductor substrate 11 resist film 11 a exposed portion 11 b unexposed portion 12 mask 13 F ₂ laser beam 14 resist pattern 20 semiconductor substrate 21 resist film 21 a exposed portion 21 b unexposed portion 22 mask 23 F ₂ laser beam 24 resist pattern 30 semiconductor substrate 31 resist film 31a exposed part 31b unexposed part 32 water-soluble resin film 33 mask 34 F ₂ laser beam 35 resist pattern 40 semiconductor substrate 41 resist film 41a exposed part 41b unexposed part 42 mask 43 F ₂ laser beam 44 resist pattern

Continuation of the front page (56) References JP-A-3-223861 (JP, A) JP-A-10-186665 (JP, A) JP-A-11-231536 (JP, A) JP-A-11-231537 (JP, A) , A) "Photopolymer Technology", edited by Yamaoka and Nagamatsu (s.63.12.30), Nikkan Kogyo Shimbun, "Microfabrication and Resist," by Saburo Nogaki, edited by The Society of Polymer Science (s.63.3.30) Kyoritsu Shuppan (58) Fields investigated (Int. Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (5)

(57) [Claims] 1. A has an absorption wavelength peak, the absorption wave
Applying a chemically amplified resist material including a base resin having a group that shifts a long peak to a longer wavelength side on a substrate to form a resist film; and forming a Xe ₂ laser beam, F ₂ Laser light, Kr
₂ laser light, after performing pattern exposure by irradiating ArKr laser or Ar ₂ laser, and a step of forming a resist pattern by developing the resist film after the pattern exposure, the group is an amino group , Trifluoromethyl group or merka
A pattern forming method, characterized in that it is a hept group . 2. The pattern forming method according to claim 1, wherein the base resin is an acrylic acid-based resin or polyvinyl phenol. 3. The pattern forming method according to claim 1, wherein said group is contained in an acid leaving group in said base resin. 4. The method according to claim 1, wherein the group is an amino group, the base resin has an aromatic ring , and the amino group is bonded to carbon constituting the aromatic ring. The pattern forming method according to the above. 5. An absorption wave having an absorption wavelength peak.
A base formed by bonding a group that shifts the long peak to the long wavelength side.
Apply chemically amplified resist material containing base resin on substrate
Forming a resist film by performing Xe ₂ laser light, F ₂ laser light, Kr
₂ Irradiation of laser light, ArKr laser light or Ar ₂ laser light
After pattern exposure and before pattern exposure
Developing the resist film to form a resist pattern
A degree, the base is patterned, characterized in that bonded to the main chain of a is and the base resin fluoroalkyl group
How .