JPH09258448A - Resist composition and production of semiconductor device using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable development without using harmful chemicals by incorporat ing a specified compd., an optical acid generating agent which generates an acid when irradiated with light and a solvent. SOLUTION: This compsn. contains a homo- or co-polymer contg. repeating units represented by the formula, an optical acid generating agent which generates an acid when irradiated with light and a solvent dissolving a polymer and the optical acid generating agent. In the formula, one of X<1> -X<4> is -OR<1> , -COOR<1> or -R<2> -OR<1> (R<1> is hydrocarbon released by an acid and R<2> is divalent hydrocarbon or a group obtd. by substituting an atom such as halogen, Si or Ti or an atomic group consisting of such atoms for part of a hydrocarbon group), another is -COR<3> (R<3> is hydrocarbon or a group obtd. by substituting an atom such as halogen, Si or Ti or an atomic group consisting of such atoms for part of a hydrocarbon group) and the remaining two are H.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist composition used in a photolithography process of a semiconductor process and a method for manufacturing a semiconductor device using the resist composition.

[0002]

2. Description of the Related Art In a conventional semiconductor process, an organic solvent or organic alkali solution is used to develop an exposed resist film.

[0003]

There are harmful chemicals in the organic solvent and organic alkaline solution used for developing the resist film. In recent years, it has been required to improve the safety of the working environment of semiconductor processes.

An object of the present invention is to provide a resist composition which can be developed without using harmful chemicals, and a method for manufacturing a semiconductor device including a resist film developing step which does not use harmful chemicals.

[0005]

According to one aspect of the present invention, a general formula

[0006]

Embedded image A repeating unit represented by the formula, wherein ¹ of X ^{1 to} X ⁴
One is -OR ¹ , -COOR ¹ , or -R ² -OR ^1.
(R ¹ is a hydrocarbon group capable of leaving by an acid, R ² is a divalent hydrocarbon group or an atom composed of an atom selected from the group consisting of halogen, silicon, germanium, oxygen, nitrogen, sulfur and titanium. Group or a substitution product of a divalent hydrocarbon group with one atom) is the first group, and the other is -COR ³ (R ³ is a hydrocarbon group or halogen, silicon, germanium, A second group represented by an atomic group composed of atoms selected from the group consisting of oxygen, nitrogen, sulfur, and titanium or a substitution product of a hydrocarbon group with one atom), and the remaining two groups are A compound composed of a homopolymer or a copolymer containing the repeating unit which is a hydrogen atom, a photoacid generator that generates an acid when irradiated with light, the compound and the photoacid generator Cash register containing solvent to dissolve DOO composition.

When a resist film formed from this resist composition is exposed to ultraviolet rays, far ultraviolet rays, vacuum ultraviolet rays, electron beams, etc., acid is generated in the exposed areas due to the presence of the photo-acid generator. With this acid, R ¹ is eliminated and replaced with a hydrogen atom to form a hydroxyl group. Since the hydroxyl group is hydrophilic,
The resist film in the region where the hydroxyl group is formed is dissolved in pure water or the like. Therefore, it is possible to develop with pure water or the like.

According to another aspect of the present invention, there is provided a resist composition in which the first group is a group represented by an alkoxyl group or —COOR ⁴ (R ⁴ is an alkyl group). According to another aspect of the present invention, a step of applying the resist composition on a surface of a semiconductor substrate to form a resist film, a step of selectively exposing the resist film, and a pure water or carbon after the exposure. A step of immersing the substrate in one liquid selected from the group consisting of alcohols of the formulas 1 to 5, an aqueous alkaline solution, and a mixed liquid in which at least two of these liquids are mixed, and developing the substrate. A manufacturing method is provided.

[0009]

DETAILED DESCRIPTION OF THE INVENTION General Formula

[0010]

Embedded image A homopolymer including a repeating unit represented by

Here, the group X ⁴ is --OR ¹ , --COOR.
¹ or —R ² —OR ¹ (R ¹ is a hydrocarbon group which is eliminated by an acid, R ² is a divalent hydrocarbon group or a group consisting of halogen, silicon, germanium, oxygen, nitrogen, sulfur, and titanium. A group represented by an atomic group composed of selected atoms or a divalent hydrocarbon group substituted by one atom), wherein the group X ³ is —COR ³ (R ³ is a hydrocarbon group or halogen. , Silicon, germanium, oxygen,
A group represented by an atomic group composed of atoms selected from the group consisting of nitrogen, sulfur, and titanium or a substitution product of a hydrocarbon group with one atom), wherein the groups X ¹ and X ² are hydrogen atoms. Is.

For example, the group X ⁴ is an alkoxyl group, --CO
OR ⁴ (R ⁴ is an alkyl group), an alkoxyphenyl group,
Alkoxy cyclohexyl group, alkoxy adamantyl group ^{or,, -R 2 -OR 1 (R} 1 is tertiary butyl (tBu), R ² has the general formula

[0013]

Embedded image And a divalent hydrocarbon group) or the like. Also, R
³ is a cyclohexyl group, a phenyl group or the like.

A photo-acid generator such as triphenylsulfonium hexafluoroantimonate (TPSSbF ₆ ) is added to the homopolymer represented by the general formula (1) to prepare a cyclohexanone solution to obtain a resist composition.

This resist composition is spin-coated on a substrate such as a semiconductor and the solvent is volatilized to form a resist film.
This resist film is selectively irradiated with exposure light such as KrF excimer laser (wavelength 248.4 nm) through a photomask. Acid is generated by the photo-acid generator in the resist film in the exposed area. At the same time, the main chain of the homopolymer is cleaved to lower the molecular weight.

After the exposure, the resist film is baked. By the acid generated in the exposure step, the hydrocarbon group R ¹ contained in the group X ⁴ in the general formula (1) is eliminated and replaced with a hydrogen atom to form a hydroxyl group.

After baking, the substrate is immersed in pure water. Since the hydroxyl group has a strong affinity with water, the resist film in the region substituted with the hydroxyl group, that is, the exposed region is dissolved in pure water. In addition, since the molecular weight of the resist film in the exposed region is lowered, the resist film is more easily melted. In this way, the resist film can be developed using pure water.

Since the resist film can be developed using pure water without using an organic solvent, an organic alkaline solution, etc., it is possible to suppress the use of harmful chemicals in the semiconductor process.

In the above-mentioned embodiment, the case where the homopolymer is used as the resin raw material of the resist composition has been described. However, the repeating unit represented by the general formula (1) and other repeating units such as methyl isopropenyl ketone. You may use the copolymer containing.

In the above embodiment, the groups X ³ and X ^{4 are}
Is described as being bonded to the same carbon atom in the main chain, but the group X ³ is bonded to one carbon atom of the two carbon atoms in the main chain constituting the repeating unit and the other carbon is Homopolymers or copolymers in which the radical X ⁴ is bonded to an atom may be used.

Thus, the groups X ³ and X are different at different carbon atoms.
^The polymer in which ⁴ is bonded is, for example, cyclohexane-2,
It can be prepared by polymerizing 3-butenoic acid-4-oxo-t-butyl ester.

Further, in the above embodiment, pure water was used as the developing solution for the resist film, but a mixed solution of pure water mixed with an alcohol having 1 to 5 carbon atoms such as methanol or ethanol may be used. Alternatively, an aqueous alkaline solution such as tetramethylammonium hydroxide may be used.
Further, a developer obtained by mixing an aqueous alkaline solution and an alcohol having 1 to 5 carbon atoms may be used.

[0023]

[Example] General formula

[0024]

[Chemical 6]

Cyclohexanepropanoic acid represented by
-Methylene-β-oxo-tert-butyl ester 1
Dissolve 0 g in 10 times the volume of toluene. Cyclohexanepropanoic acid-α-methylene-β-oxo-tert-butyl ester was added with 10 mol% of N, N-azobisisobutyronitrile (AIBN), and the mixture was heated to 80 ° C. and adjusted to 1
Hold for 0 hours to cause addition polymerization reaction.

This solution was poured into a large amount of methanol,
By filtering the precipitate, 6.7 g of cyclohexanepropanoic acid-α-methylene-β-oxo-tert-butyl ester homopolymer could be obtained. That is, the yield was 67%. When the molecular weight was measured by gel permeation chromatography, the molecular weight was 5,600.

To the homopolymer obtained by the above method, 5% by weight of triphenylsulfonium hexafluoroantimonate (TPSSbF ₆ ) was added, and the resin content was 12%.
A cyclohexanone solution with a weight% is prepared. TPS
SbF ₆ is a photoacid generator.

This cyclohexanone solution was spin-coated on the surface of the silicon substrate with the silicon surface exposed, and the temperature was raised to 150 ° C.
Is prebaked to form a resist film having a thickness of about 0.5 μm. KrF with a numerical aperture NA of the lens of 0.45
An excimer laser stepper is used to selectively expose the resist film through a photomask having a line and space pattern with various line widths formed. The reduction projection exposure has a magnification of 1/5.

After exposure, post baking is performed at 150 ° C. for 60 seconds. Then, the silicon substrate is immersed in pure water at a temperature of 20 ° C. for 2 minutes for development. By the above method, a pattern having a minimum line width of 0.375 μm could be resolved.

In the above examples, cyclohexanepropanoic acid-α-methylene-β-oxo-tert-butyl ester was used as the monomer for causing the addition polymerization reaction, but other monomers may be used. .

As the monomer, the general formula

[0032]

Embedded image

Benzenepropanoic acid-α-methylene-β-oxo-tert-butyl ester represented by
A homopolymer was produced in the same manner as in the above-mentioned example. By this method, a homopolymer having a molecular weight of 6500 was obtained with a yield of 73%. Using this homopolymer, a resist composition was prepared in the same manner as in the above Example, and exposed and developed.
A pattern with a minimum line width of 0.375 μm could be resolved.

As the monomer, the general formula

[0035]

Embedded image

When 1-t-butoxy-2-oxo-cyclohexylpropene represented by the following formula is used, the yield is 45
%, A homopolymer having a molecular weight of 5500 could be obtained, and a pattern having a minimum line width of 0.40 μm could be resolved.

As the monomer, the general formula

[0038]

Embedded image

1-oxo-2methylene-3-represented by
When methyl-3-t-butoxy-cyclohexylbutane was used, a homopolymer having a molecular weight of 4600 could be obtained with a yield of 52%, and a pattern having a minimum line width of 0.40 μm could be resolved.

Cyclohexanepropanoic acid-α-methylene-β-oxo-tert-butyl ester as a monomer

[0041]

Embedded image A copolymer was prepared in the same manner as in the above-mentioned example using a monomer raw material prepared by mixing methyl isopropenyl ketone represented by the formula (1) with a molar ratio of 98: 2. By this method, a copolymer having a molecular weight of 6400 was obtained with a yield of 56%. Using this copolymer, a resist composition was prepared in the same manner as in the above-mentioned Example and exposed and developed. As a result, a pattern having a minimum line width of 0.40 μm could be resolved.

Comparison was made when cyclohexanepropanoic acid-α-methylene-β-oxo-tert-butyl ester or benzenepropanoic acid-α-methylene-β-oxo-tert-butyl ester was used as the monomer for the polymerization reaction. It was possible to obtain a polymer in an extremely high yield and to realize a relatively high resolution.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0044]

As described above, according to the present invention,
The resist film in the exposed area can be made hydrophilic and development can be performed using pure water or the like. Since no harmful chemicals are used, a safe working environment can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H01L 21/30 568 569F

Claims (5)

[Claims] 1. A compound of the general formula A repeating unit represented by the formula, wherein ¹ of X ^{1 to} X ⁴
One is -OR ¹ , -COOR ¹ , or -R ² -OR ^1.
(R ¹ is a hydrocarbon group capable of leaving by an acid, R ² is a divalent hydrocarbon group or a substituted product thereof, and is selected from the group consisting of halogen, silicon, germanium, oxygen, nitrogen, sulfur, and titanium. A first group represented by an atomic group composed of atoms or a substitution product of one atom,
The other one is -COR ³ (R ³ is a hydrocarbon group or halogen, silicon, germanium, oxygen, nitrogen, sulfur,
And a second group represented by an atomic group composed of atoms selected from the group consisting of and titanium or a substitution product of a hydrocarbon group with one atom), and the remaining two are hydrogen atoms. A resist comprising a compound composed of a homopolymer or a copolymer containing units, a photoacid generator that generates an acid when irradiated with light, and a solvent that dissolves the compound and the photoacid generator. Composition. 2. The resist composition according to claim 1, wherein the first group is an alkoxyl group or a group represented by —COOR ⁴ (R ⁴ is an alkyl group). 3. A step of applying the resist composition according to claim 1 or 2 onto a surface of a semiconductor substrate to form a resist film, a step of selectively exposing the resist film, and a pure step after the exposure. A step of immersing and developing the substrate in one liquid selected from the group consisting of water, an alcohol having 1 to 5 carbon atoms, an aqueous alkaline solution, and a mixed liquid obtained by mixing at least two of these liquids. Manufacturing method of semiconductor device. 4. A step of applying the resist composition according to claim 1 or 2 onto a surface of a semiconductor substrate to form a resist film, a step of selectively exposing the resist film, and a step of exposing the resist film after the exposure. It is selected from the group consisting of a step of baking below the glass transition temperature of the resist film (resin), pure water, an alcohol having 1 to 5 carbon atoms, an aqueous alkaline solution, and a mixed solution obtained by mixing at least two of these liquids. And a step of immersing and developing the substrate in another liquid. 5. A compound of the general formula A repeating unit represented by the formula, wherein ¹ of X ^{1 to} X ⁴
One is -OR ¹ , -COOR ¹ , or -R ² -OR ^1.
(R ¹ is a hydrocarbon group capable of leaving by an acid, R ² is a divalent hydrocarbon group or a substituted product thereof, and is selected from the group consisting of halogen, silicon, germanium, oxygen, nitrogen, sulfur, and titanium. A first group represented by an atomic group composed of atoms or a substitution product of one atom,
The other one is -COR ³ (R ³ is a hydrocarbon group or halogen, silicon, germanium, oxygen, nitrogen, sulfur,
And a second group represented by an atomic group composed of atoms selected from the group consisting of and titanium or a substitution product of a hydrocarbon group with one atom), and the remaining two are hydrogen atoms. A compound consisting of a homopolymer or a copolymer containing a unit, a solvent that dissolves the compound and the photoacid generator, is applied onto the surface of the semiconductor substrate, a step of forming a resist film, A step of selectively exposing the resist film; and, after the exposure, selected from the group consisting of pure water, an alcohol having 1 to 5 carbon atoms, an aqueous alkaline solution, and a mixed liquid in which at least two of these liquids are mixed. And a step of immersing the substrate in one liquid and developing the substrate.