JP2000035664A - Radiation-sensitive material and method of forming pattern - Google Patents

Abstract

(57) Abstract: A radiation-sensitive material and a pattern forming method using the radiation-sensitive material, the radiation-sensitive material and the pattern formation capable of improving a difference in a dissolution rate in a developing solution between an exposed part and an unexposed part. Provide a way. SOLUTION: A base resin composed of a film-forming polymer, a photosensitive agent, and a compound represented by the general formula: (Wherein, R ₁ represents an atomic group having 2 to 30 carbon atoms; R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms,
Represents a hydroxyalkyl group of 10 or a haloalkyl group having 1 to 10 carbon atoms; n represents an integer of 2 to 8;
Represents an integer of 6. ) And a solvent that dissolves the base resin, the photosensitive agent and the lactone derivative compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a radiation-sensitive material and a pattern forming method using the radiation-sensitive material.

[0002]

2. Description of the Related Art In recent years, integration of semiconductor integrated circuits has progressed, and LSIs and VLSIs have been put into practical use. At the same time, the minimum pattern extends to a sub-half micron region, and tends to be further miniaturized. To form a fine pattern, the target substrate on which the thin film has been formed is coated with a resist film, and after performing selective exposure, development is performed to create a resist pattern. Using this as a mask, dry etching is performed, and then the resist is removed. Therefore, it is essential to use a lithography technique to obtain a desired pattern. Ultraviolet rays were initially used as an exposure light source for this purpose, but with the miniaturization of patterns, far ultraviolet rays with short wavelengths, electron beams, X-rays, and the like have come to be used as light sources. Further, in order to miniaturize the pattern, not only the wavelength of the light source is shortened, but also a radiation-sensitive material having a high resolution according to the characteristics of the light source is required.

[0003]

Generally, a radiation-sensitive material having a large difference in the dissolution rate of the exposed part and the unexposed part in the developing solution has a higher resolution. For this reason, in designing a radiation-sensitive material, it is an important issue how to make a difference in dissolution rate between an exposed portion and an unexposed portion.

An object of the present invention is to provide a radiation-sensitive material and a pattern forming method capable of improving the difference in dissolution rate between an exposed portion and an unexposed portion.

[0005]

The object of the present invention is to provide a base resin composed of a film-forming polymer, a photosensitive agent,

[0006]

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(Wherein, R ₁ represents an atomic group having 2 to 30 carbon atoms; R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms or 1 carbon atom) N represents an integer of 2 to 8; m represents an integer of 1 to 6), the base resin, the photosensitive agent and the lactone derivative compound And a solvent for dissolving the compound. By adding the lactone derivative compound to a radiation-sensitive material in which a base resin and a photosensitive agent are dissolved in a solvent, the solubility of a dissolved portion of the radiation-sensitive material can be improved. This makes it possible to increase the difference in the dissolution rate between the dissolved part and the non-dissolved part, that is, the exposed part and the unexposed part. Therefore, the resolution of the radiation-sensitive material can be improved.

In the above radiation-sensitive material, the composition ratio of the lactone derivative compound is preferably less than 50% by weight based on the base resin. If the weight ratio to the base resin is 50% or more, the film-forming properties and other properties of the radiation-sensitive material may be degraded. Therefore, it is desirable to select the amount of the lactone derivative compound within such a range.

Another object of the present invention is to provide a base resin made of a film-forming polymer, a photosensitive agent,

[0010]

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Wherein R and R ′ are each hydrogen,
Hydroxyl group, alkyl group having 1 to 10 carbon atoms, 1 to 10 carbon atoms
Represents a hydroxyalkyl group or a haloalkyl group having 1 to 10 carbon atoms. The present invention is also achieved by a radiation-sensitive material comprising a lactone represented by the formula (1) and a solvent dissolving the base resin, the photosensitive agent and the lactone. By adding the lactone to a radiation-sensitive material in which a base resin and a photosensitive agent are dissolved in a solvent, the solubility of a dissolved portion of the radiation-sensitive material can be improved.
This makes it possible to increase the difference in the dissolution rate between the dissolved part and the non-dissolved part, that is, the exposed part and the unexposed part. Therefore, the resolution of the radiation-sensitive material can be improved.

In the above radiation sensitive material, the composition ratio of the lactone is preferably 5 to 200% by weight based on 100% by weight of the composition ratio of the base resin and the photosensitive agent. By adding lactone in the above range, the sensitivity and resolution of the radiation-sensitive material can be improved.

In the above radiation-sensitive material, the lactone portion of the lactone derivative compound or the lactone may be:

[0014]

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One substance selected from the group can be applied.

In the above radiation-sensitive material, it is desirable that the lactone portion of the lactone derivative compound or the lactone be converted into a hydroxy acid by ring opening in an aqueous alkali solution. Since the acidity of the radiation-sensitive material can be increased by opening the ring in an alkaline aqueous solution,
As the lactone derivative compound, a compound having such properties can be applied.

In the above radiation-sensitive material, an aqueous solution mainly containing either tetramethylammonium hydroxide or potassium hydroxide can be used as the alkaline aqueous solution.

The above object is also achieved by providing a base resin made of a film-forming polymer, a photosensitive agent,

[0019]

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(Wherein, R ₁ represents an atomic group having 2 to 30 carbon atoms; R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, or 1 carbon atom) A haloalkyl group of from 10 to 10; n represents an integer of from 2 to 8; m represents an integer of from 1 to 6). A step of selectively exposing the radiation-sensitive material on the substrate to radiation with radiation, and a step of developing the radiation-sensitive material on the substrate to be processed with an alkaline aqueous solution to form a predetermined resist pattern. This is also achieved by a pattern forming method characterized by the following. By forming a resist pattern using the above-described radiation-sensitive material, the difference in dissolution rate between the exposed portion and the unexposed portion of the radiation-sensitive material can be increased, so that the resolution of the resist pattern can be improved. it can.

[0021] The object of the present invention is to provide a base resin made of a film-forming polymer, a photosensitive agent, and a general formula on a substrate to be processed.

[0022]

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Wherein R and R ′ are each hydrogen,
Hydroxyl group, alkyl group having 1 to 10 carbon atoms, 1 to 10 carbon atoms
Represents a hydroxyalkyl group or a haloalkyl group having 1 to 10 carbon atoms. A) applying a radiation-sensitive material having a lactone and a solvent, selectively exposing the radiation-sensitive material on the substrate to radiation, and applying the radiation-sensitive material on the substrate. Forming a predetermined resist pattern by developing the material with an aqueous alkali solution. By forming a resist pattern using the above-described radiation-sensitive material, the difference in dissolution rate between the exposed portion and the unexposed portion of the radiation-sensitive material can be increased, so that the resolution of the resist pattern can be improved. it can.

[0024]

[First Embodiment] A radiation-sensitive material according to a first embodiment of the present invention will be described.

The radiation-sensitive material according to the first embodiment of the present invention comprises a base resin made of a film-forming polymer, a photosensitive agent,

[0026]

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(Wherein, R ₁ represents an atomic group having 2 to 30 carbon atoms; R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms or 1 carbon atom) Represents a haloalkyl group of 10 to 10; n represents an integer of 2 to 8; m represents an integer of 1 to 6), a base resin, a photosensitive agent, and a lactone derivative compound. It has a main feature of having a solvent.

In a normal resist pattern forming process, a predetermined pattern is exposed on a radiation-sensitive material coated on a substrate, developed in an aqueous alkali solution such as tetramethylammonium hydroxide or potassium hydroxide, and the predetermined pattern is formed. Is formed. At this time, the exposed portion of the positive resist dissolves in the developer, and the unexposed portion of the negative resist dissolves in the developer. The developer penetrates into the portion that dissolves in the developer and dissolution occurs.

In the reaction of such a development process, if the acidity of the dissolved portion increases simultaneously with the intrusion of the developing solution, the solubility in the aqueous alkali solution is further increased, and as a result, the dissolution of the exposed portion and the unexposed portion is increased. The speed difference can be enlarged.

From this viewpoint, in the present embodiment, a substance that increases the acidity of the radiation-sensitive material with the intrusion of the developer is represented by a general formula

[0031]

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(Wherein, R ₁ represents an atomic group having 2 to 30 carbon atoms; R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, or N represents an integer of 2 to 8; m represents an integer of 1 to 6), to a radiation-sensitive material.

As a result of intensive studies by the present inventors, they have found that this lactone derivative compound forms a hydroxyl group and a carboxyl group by ring opening in an aqueous alkali solution.
That is, this substance functions to generate a carboxyl group upon contact with an aqueous alkaline solution to increase the acidity. Therefore, by adding this substance to the radiation-sensitive material, the difference in dissolution rate between the dissolved portion and the non-dissolved portion can be increased, so that a radiation-sensitive material having high resolution can be constituted.

In the above-mentioned lactone derivative compound, for example, the lactone moiety has a general formula

[0035]

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A five-membered gamma lactone represented by the general formula

[0037]

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A 6-membered δ-lactone represented by the general formula

[0039]

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A lactone derivative compound, which is another lactone represented by any of the above, can be applied. These lactone derivative compounds are suitable for the radiation-sensitive material of the present invention because they ring-open in an aqueous alkaline solution to become hydroxy acids.

The lactone derivative compound to be added to the radiation-sensitive material preferably has a composition ratio of the lactone derivative compound of less than 50% by weight relative to the base resin. When the weight ratio to the base resin is 50% or more,
This is because the film forming properties and other properties of the radiation-sensitive material may be deteriorated.

Incidentally, examples of radiation-sensitive materials containing lactones include those described in Japanese Patent Application No. 7-181677 or Japanese Patent Application No. 9-90637. However, these radiation-sensitive materials contain a lactone moiety in the polymer side chain of the base resin in the positive type chemically amplified resist, and the present invention uses a lactone derivative compound as a non-polymeric low molecular weight additive. Is different from the above radiation-sensitive material.

The effects of the present invention can be obtained by adding the above lactone derivative compound to various radiation-sensitive materials, regardless of the characteristics such as positive-type and negative-type, as long as the material is a radiation-sensitive material capable of performing alkali development. it can. For example, the present invention can be applied to a radiation-sensitive material comprising a combination of the following materials.

(Base Resin) As the base resin of the radiation-sensitive material, any resin can be used as long as it can be mixed with a lactone derivative compound and has developability in an aqueous alkali solution.

For example, acrylate-based polymers, methacrylate-based polymers, vinylphenol-based polymers, N-substituted maleimide-based polymers, styrene-based polymers and the like can be used. In particular, acrylate-based and methacrylate-based polymers are important in that when deep ultraviolet light is used as an exposure light source, absorption of light having a wavelength in the deep ultraviolet region is small. In other words, when deep ultraviolet light is used as the exposure light source, a structure that generally does not include a luminophore having a large molar extinction coefficient such as an aromatic ring or a conjugated double bond that largely absorbs light in the deep ultraviolet region. It is desirable to use a polymer having

When an exposure light source in a short wavelength region such as an ArF excimer laser is used, it is necessary to have dry etching resistance and transparency at the wavelength (193 nm) of the exposure light source. An ester which does not contain an aromatic ring having a strong absorption, but instead has a high dry etching resistance and contains a plurality or polycyclic alicyclic hydrocarbon moieties represented by, for example, an adamantyl group or a norbornyl group. It is desirable to use polymers having groups. Here, as the alicyclic hydrocarbon portion to be contained in the ester group, for example, a general formula

[0047]

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Adamantane and its derivatives represented by
General formula

[0049]

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Norbornane and its derivatives represented by
General formula

[0051]

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Perhydroanthracene represented by the formula:

[0053]

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Perhydronaphthalene and its derivatives represented by the general formula:

[0055]

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The tricyclo [5.2.1.0
^2,6 ] decane and its derivatives, general formula

[0057]

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Bicyclohexane and its derivatives represented by the general formula

[0059]

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Spiro [4,4] nonane represented by the following formula:

[0061]

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Spiro [4,4] decane and its derivatives represented by

A resin having a lactone moiety in the side chain of the base resin, for example, a film-forming polymer having a protective group-containing carboxyl group in the side chain of a monomer unit, which is insoluble in a basic aqueous solution Yes, provided that, when the carboxyl protecting group is eliminated from the side chain, the carboxyl group becomes soluble in a basic aqueous solution, and the protecting group has the general formula

[0064]

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(Wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms and may be substituted or unsubstituted; n is an integer of 1 to 4) ) Can be applied.

(Photosensitizer) As the photosensitizer of the radiation-sensitive material, for example, the following materials can be applied.

For example, as a photoacid generator used in a chemically amplified resist, a substance that generates a protonic acid by irradiation with radiation such as ultraviolet rays, far ultraviolet rays, vacuum ultraviolet rays, electron beams, X-rays, and laser beams can be widely used. , For example, the general formula

[0068]

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(Where Ar is a substituted or unsubstituted aromatic group, for example, phenyl, halogen, methyl, t-
Represents a phenyl group or the like substituted with a butyl group, an aryl group, or the like, or an alicyclic group; X ₁ represents BF ₄ , BF ₆ , P
F ₆ , AsF ₆ , SbF ₆ , CF ₃ SO ₃ , C ₃ F ₇ SO ₃ , C
lO ₄ represents the like. ), An iodonium salt represented by the general formula

[0070]

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(Where R₁, R_Two, R_ThreeAnd R_FourAre the same
Each may be hydrogen or any
Substituents such as halogens, alkyl groups, aryl groups, etc.
Represents, for example, R₁, R_TwoAnd R_ThreeIs a phenyl group, etc.
R_FourIs a methyl group or the like; Ar is substituted or unsubstituted
Substituted aromatic groups such as phenyl, halogen, methyl
Phenyl substituted with phenyl, t-butyl, aryl, etc.
X represents an alicyclic group or the like; or X₁Is BF_Four, BF₆,
PF₆, AsF₆, SbF₆, CF_ThreeSO_Three, C_ThreeF₇SO _Three,
ClO_FourAnd so on. ) And the like,
General formula

[0072]

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(Wherein R ₄ represents hydrogen or any substituent such as halogen, alkyl group, aryl group, etc .; Ar represents a substituted or unsubstituted aromatic group such as phenyl group, halogen, methyl group , A phenyl group substituted with a t-butyl group, an aryl group, or the like, or an alicyclic group.)

[0074]

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(Wherein X ₂ is hydrogen, an alkyl group, an aryl group, a halogen such as Cl, Br or I, provided that at least one of X ₂ is a halogen, and —C (X ₂ ) _{One of the three} groups may be a substituted or unsubstituted aryl group or an alkenyl group);

[0076]

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Wherein X ₂ is hydrogen, an alkyl group, an aryl group, a halogen such as Cl, Br or I, provided that at least one of X ₂ is a halogen, and —C (X ₂ ) _{One of the three} groups may be a substituted or unsubstituted aryl group or an alkenyl group);

[0078]

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(Wherein X ₂ is hydrogen, an alkyl group, an aryl group, a halogen such as Cl, Br or I, provided that at least one of X ₂ is a halogen, and —C (X ₂ ) _{One of the three} groups may be a substituted or unsubstituted aryl group or an alkenyl group), a general formula: Ar-SO ₂ -SO ₂ -Ar (wherein Ar is A substituted or unsubstituted aromatic group, for example, a phenyl group, a halogen, a methyl group, a t-butyl group,
Represents a phenyl group or the like substituted with an aryl group or the like, or an alicyclic group. ), A disulfone derivative represented by the general formula

[0080]

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(Where X ₁ is BF ₄ , BF ₆ , PF ₆ , As
It represents F ₆ , SbF ₆ , CF ₃ SO ₃ , C ₃ F ₇ SO ₃ , ClO _{4 and the} like. ) And the like, a general formula

[0082]

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Sulfonic acid esters represented by the following formulas:

[0084]

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(Wherein X ₂ is hydrogen, an alkyl group, an aryl group, halogen such as Cl, Br or I, provided that at least one of X ₂ is halogen and —C (X ₂ ) _{One of the three} groups may be a substituted or unsubstituted aryl group or an alkenyl group.), For example.

(Solvent) Examples of the solvent for dissolving the composition include ethyl lactate, methyl amyl ketone,
Methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, propylene glycol methyl ether acetate, or a mixture of solvents selected from these can be used.

In addition, auxiliary solvents such as butyl acetate and propylene glycol methyl ether may be added.

[Second Embodiment] The radiation sensitive material according to the second embodiment of the present invention will be described.

The radiation-sensitive material according to the second embodiment of the present invention comprises a base resin composed of a film-forming polymer, a photosensitive agent,

[0090]

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Wherein R and R ′ are each hydrogen,
Hydroxyl group, alkyl group having 1 to 10 carbon atoms, 1 to 10 carbon atoms
Represents a hydroxyalkyl group or a haloalkyl group having 1 to 10 carbon atoms. ) And a solvent that dissolves the base resin, the photosensitive agent and the lactone. That is, the radiation-sensitive material according to the present embodiment is different from the radiation-sensitive material according to the first embodiment in that
In place of the lactone derivative compound represented by
4] is added. In addition,
R and R 'constituting the lactone may be the same or different.

The effect of adding a lactone to the radiation-sensitive material according to the present embodiment is the same as the case where a lactone derivative compound is added to the radiation-sensitive material according to the first embodiment. That is, even when a lactone is introduced instead of the lactone derivative compound, the lactone is opened in an aqueous alkaline solution to generate a hydroxyl group and a carboxyl group. Therefore, by configuring the radiation-sensitive material described above, the difference in dissolution rate between the dissolved portion and the non-dissolved portion can be increased, so that a radiation-sensitive material having high resolution can be configured.

As the above lactone, various lactones listed in [Formula 13] to [Formula 15] in the first embodiment can be applied. These lactones are suitable for the radiation-sensitive material of the present invention because they ring-open in an aqueous alkali solution to become hydroxy acids.

The lactone to be added to the radiation-sensitive material is a resist solid content (base resin excluding solvent, photosensitive agent, etc.).
Is desirably 5 to 200% by weight with respect to 100% by weight. If the added amount of the lactone is less than 5% by weight, the improvement in resist sensitivity and resolution is not sufficient. To improve both resist sensitivity and resolution,
It is desirable to set the amount of the lactone to be in the range of about 10 to 50% by weight (see Example 5 described later).

It is desirable that the amount of lactone to be added is appropriately selected according to the required resist sensitivity, resolution, film forming properties of the radiation-sensitive material, and other characteristics.

The effect of the present invention can be obtained by adding the above lactone to various radiation-sensitive materials, regardless of the characteristics such as a positive type and a negative type, as long as the material is subjected to alkali development. Various materials listed in the first embodiment can be applied to other constituent materials such as a base resin, a photosensitive agent, and a solvent.

[0097]

EXAMPLES Example 1 Terephthalic acid was heated in thionyl chloride to synthesize terephthalic acid chloride, which was then reacted with 2 moles of mevalonic lactone to obtain a diester.

Next, the diester 2 prepared as described above was used.
0 parts, 100 parts of 30% t-butoxycarbonylated polyvinylphenol and 5 parts of triphenylsulfonium triflate are dissolved in 400 parts of ethyl lactate,
A resist solution was prepared.

Subsequently, the thus-prepared resist solution was subjected to HMDS (hexamethyldisilane) treatment.
Spin coating was performed on an inch Si wafer to a thickness of about 0.7 μm, and baking was performed at 90 ° C. for 2 minutes on a hot plate to form a resist film.

Thereafter, the resist film thus obtained is replaced with K
Exposure was performed with an rF excimer stepper (NA = 0.50).
Next, PEB (post-exposure bake:
PostExposure Bake) and 2.38% TMAH
It was developed with an aqueous solution of (tetramethylammonium hydroxide) for 1 minute.

As a result, the resist film was about 0.25 μm
Could be resolved.

Comparative Example 1 100 parts of polyvinylphenol having 30% t-butoxycarbonylation and 5 parts of triphenylsulfonium triflate were dissolved in 400 parts of ethyl lactate to prepare a resist solution.

Next, the thus-prepared resist solution is spin-coated on a 6-inch Si wafer subjected to HMDS processing so as to have a thickness of about 0.7 μm, and is heated on a hot plate at a temperature of 90 ° C. for 2 minutes. Was performed to form a resist film.

Thereafter, the resist film thus obtained is replaced with K
Exposure was performed with an rF excimer stepper (NA = 0.50).
Next, PEB is performed at a temperature of 90 ° C. for 2 minutes, and 2.38.
% Of TMAH aqueous solution for 1 minute.

As a result, the resolution limit of the resist was about 0.2
75 μm, which was inferior to the case of Example 1 in which the diester was added.

Example 2 Cyclohexanedicarboxylic acid was heated in thionyl chloride to synthesize terephthalic acid chloride, and then reacted with 2 moles of mevalonic lactone.
The diester was obtained.

Next, the diester 2 prepared as described above was prepared.
0 parts, 100 parts of a 1: 1 copolymer of mevalonic lactone methacrylate and 2-adamantyl methacrylate, and 2 parts of triphenylsulfonium triflate are dissolved in 350 parts of propylene glycol monomethyl ether acetate and 50 parts of γ-butyrolactone. The resist solution was adjusted.

Subsequently, the resist solution thus adjusted was spin-coated on a 6-inch Si wafer subjected to HMDS treatment so that the film thickness became about 0.5 μm, and the temperature was set to 110 ° C. on a hot plate at a temperature of 110 ° C. Baking was performed for 2 minutes to form a resist film.

Thereafter, the resist film thus obtained is replaced with A
Exposure was performed with an rF excimer stepper (NA = 0.55).
Next, PEB is performed at a temperature of 110 ° C. for 2 minutes, and 2.3.
It was developed with an 8% aqueous TMAH solution for 1 minute.

As a result, the resist film was about 0.15 μm
Could be resolved.

Comparative Example 2 100 parts of a 1: 1 copolymer of mevalonic lactone methacrylate and 2-adamantyl methacrylate, 2 parts of triphenylsulfonium triflate, 350 parts of propylene glycol monomethyl ether acetate and 50 parts of γ -Dissolved in butyrolactone to prepare a resist solution.

Next, the resist solution thus adjusted is spin-coated on a 6-inch Si wafer which has been subjected to HMDS processing so as to have a film thickness of about 0.5 μm. The resist film was formed by baking for minutes.

Thereafter, the resist film thus obtained is replaced with A
Exposure was performed with an rF excimer stepper (NA = 0.55).
Next, PEB is performed at a temperature of 110 ° C. for 2 minutes, and 2.3.
It was developed with an 8% aqueous TMAH solution for 1 minute.

As a result, the resolution limit of the resist was about 0.1
It was 75 μm, which was inferior to the case of Example 2 in which diester was added.

Example 3 After heating o-phthalic acid in thionyl chloride to synthesize terephthalic acid chloride, it was reacted with twice the molar amount of mevalonic lactone to obtain a diester.

Next, the diester 3 prepared as described above was used.
0 g was dissolved in 1Qt of a commercially available positive resist (TOK-P015: manufactured by Tokyo Ohka Co., Ltd.) to prepare a resist solution.

Subsequently, the resist solution thus adjusted was spin-coated on a 6-inch Si wafer subjected to HMDS processing so that the film thickness became about 0.7 μm, and the temperature was set to 90 ° C. on a hot plate at a temperature of 90 ° C. Baking was performed for 2 minutes to form a resist film.

Thereafter, the resist film thus obtained is replaced with K
Exposure was performed with an rF excimer stepper (NA = 0.50).
Next, PEB is performed at a temperature of 90 ° C. for 1 minute, and 2.38.
% Of TMAH aqueous solution for 1 minute.

As a result, the resist film has a thickness of about 0.215 μm.
m could be resolved.

Comparative Example 3 A commercially available positive resist (TO)
K-P015: manufactured by Tokyo Ohka Co., Ltd.) is spin-coated on a 6-inch Si wafer that has been subjected to HMDS processing so as to have a film thickness of about 0.7 μm.
Baking was performed for 2 minutes to form a resist film.

Thereafter, the resist film thus obtained is replaced with K
Exposure was performed with an rF excimer stepper (NA = 0.50).
Next, PEB is performed at a temperature of 90 ° C. for 1 minute, and 2.38.
% Of TMAH aqueous solution for 1 minute.

As a result, the practical resolution limit under these conditions was about 0.23 μm, which was inferior to the case of Example 3 in which diester was added.

[Example 4] Terephthalic acid was heated in thionyl chloride to synthesize terephthalic acid chloride, and then reacted with 2 moles of mevalonic lactone to obtain a diester.

Next, the diester 3 prepared as described above was used.
0 g was dissolved in 1 Qt of a commercially available negative resist (SAL-601: manufactured by Shipley) to prepare a resist solution.

Subsequently, the resist solution thus adjusted was spin-coated on a 6-inch Si wafer subjected to HMDS processing so that the film thickness became about 0.4 μm, and the temperature was 90 ° C. on a hot plate. The resist film was formed by baking for 2 minutes.

Thereafter, the resist film thus obtained was exposed to an electron beam. Next, PEB was performed for 1 minute at a temperature of 110 ° C., and development was performed for 1 minute with a 2.38% TMAH aqueous solution.

As a result, the resist film becomes about 0.13 μm
Could be resolved.

Comparative Example 4 A commercially available negative resist (SA)
L-601: Shipley Co., Ltd.) is spin-coated on a 6-inch HMDS-treated Si wafer to a thickness of about 0.4 μm, and heated on a hot plate at a temperature of 90 ° C. for 2 hours.
The resist film was formed by baking for minutes.

After that, the resist film thus obtained was exposed to an electron beam. Next, PEB was performed for 1 minute at a temperature of 110 ° C., and development was performed for 1 minute with a 2.38% TMAH aqueous solution.

As a result, the practical resolution limit under these conditions was about 0.16 μm, which was inferior to the case of Example 3 in which diester was added.

Example 5 Polyvinyl phenol / t-butyl acrylate copolymer (polyvinyl phenol: t-butyl acrylate = 55: 45) as a base resin
100 wt%, triphenylsulfonium triflate as an acid generator 5 wt%, and a lactone represented by a general formula

[0132]

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Γ-butyrolactone represented by the following formula:
0, 50, 100, 150 or 200 wt% or 510 wt% of ethyl lactate was prepared as a solvent without being added, and these were mixed to obtain a resist solution.

Next, HMDS was spin-coated on the silicon wafer as an adhesion enhancer, and baked on a hot plate at a temperature of 110 ° C. for 60 seconds.

Subsequently, the above-mentioned resist solution is spin-coated on the silicon wafer subjected to the HMDS treatment so as to have a coating film thickness of about 0.8 μm. The resist film was formed by baking for 2 seconds.

After that, the thus obtained resist film has
A single line having a data length of 0.1 μm was drawn by an electron beam exposure apparatus using an electron beam having an acceleration voltage of 30 keV.

Next, PE at a temperature of 105 ° C. for 120 seconds.
B was performed.

Subsequently, the resist film was changed to a 2.38% TM
Developed for 90 seconds with AH aqueous solution.

Thus, the resist sensitivity and the resolution were evaluated for the respective radiation-sensitive materials having different lactone addition amounts. The resist sensitivity was evaluated based on the minimum exposure amount (optimal exposure amount) at which a pattern was formed, and the resolution was evaluated based on the line width at that time.

As a result, as shown in FIG. 1, the resist sensitivity was 10 to 2 wt% when the amount of lactone added was 10 to 20 wt%.
About 0% improvement was observed. When the addition amount exceeded about 50 wt%, the resist sensitivity was conversely reduced. On the other hand, as shown in FIG. 2, the resolution was improved as the added amount of lactone was increased, and about 30% improvement was observed when the added amount was in the range of 20 to 200 wt%.

Example 6 Polyvinyl phenol / t-butyl acrylate copolymer (polyvinyl phenol: t-butyl acrylate = 55: 45) as a base resin
100 wt%, triphenylsulfonium triflate as an acid generator 5 wt%, and a lactone represented by a general formula

[0142]

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Γ-butyrolactone represented by the formula:
Or without addition, 510 wt% of ethyl lactate as a solvent,
Each was prepared and mixed to obtain a resist solution.

Next, HMDS was spin-coated as an adhesion enhancer on the silicon wafer, and baked on a hot plate at a temperature of 110 ° C. for 60 seconds.

Subsequently, the resist solution was spin-coated on the HMDS-treated silicon wafer so as to have a coating thickness of about 0.8 μm, and then on a hot plate at a temperature of 110 ° C. and 120 ° C. The resist film was formed by baking for 2 seconds.

After that, the thus obtained resist film has
A hole pattern having a data length of 0.12 μm was drawn by an electron beam exposure apparatus using an electron beam having an acceleration voltage of 50 keV.

Next, PE at a temperature of 105 ° C. for 120 seconds.
B was performed.

Subsequently, the resist film was changed to a 2.38% TM
Developed for 90 seconds with AH aqueous solution.

FIG. 3 is a view simulating a cross-sectional photograph of the hole pattern thus formed.

As shown in the figure, in the sample to which lactone was not added, pits were confirmed at the upper and lower portions of the hole (FIG. 3 (b)). Are opened straight (FIG. 3A). This result indicates that the addition of lactone improves the resist resolution.

At this time, the sensitivity of the resist was 3.5 μCcm ⁻² when no lactone was added, and changed to 3.5 μCcm ⁻² when lactone was added.
It improved to 0 μCcm ⁻² . The resolution was 0.152 μm when no lactone was added, and was 0.1 to 0.2 μm when lactone was added.
It has improved to 129 μm.

Further, the relationship between the exposure amount and the hole opening diameter of the sample to which lactone was added and the sample to which lactone was not added was examined. The fluctuation of the hole diameter was small (see FIG. 4). That is, it was found that the addition of lactone increased the exposure margin and made it easier to apply to the actual process.

[Example 7] In Example 6, [Formula 36]
Instead of γ-butyrolactone shown in the general formula

[0154]

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A lactone represented by the formula (1) was added to prepare a resist solution, and the same evaluation was performed on the resist sensitivity and resolution.

Table 1 summarizes the results. In Table 1, the types of lactones are [Chemical Formula 36] and [Chemical Formula 3].
7] in Roman numerals.

[0157]

[Table 1]

As shown in Table 1, some lactones lower the resist sensitivity in some cases, but it was found that the resolution was uniformly improved when any of the lactones was added. Since the resist sensitivity greatly depends on the amount of lactone added as shown in FIG. 1, it is considered that the sensitivity can be improved by optimizing the amount of lactone having reduced resist sensitivity.

[0159]

As described above, according to the present invention, a base resin comprising a film-forming polymer, a photosensitive agent,

[0160]

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(Wherein, R ₁ represents an atomic group having 2 to 30 carbon atoms; R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, or N represents an integer of 2 to 8; m represents an integer of 1 to 6), the base resin, the photosensitive agent and the lactone derivative compound And a solvent that dissolves the radiation-sensitive material, so that the solubility of the dissolved portion of the radiation-sensitive material can be improved. This makes it possible to increase the difference in the dissolution rate between the dissolved part and the non-dissolved part, that is, the exposed part and the unexposed part. Therefore, the resolution of the radiation-sensitive material can be improved.

A base resin composed of a film-forming polymer, a photosensitive agent,

[0163]

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Wherein R and R ′ are each hydrogen,
Hydroxyl group, alkyl group having 1 to 10 carbon atoms, 1 to 10 carbon atoms
Represents a hydroxyalkyl group or a haloalkyl group having 1 to 10 carbon atoms. ) And a solvent for dissolving the base resin, the photosensitizer and the lactone derivative compound, to improve the solubility of the dissolved portion of the radiation-sensitive material. Can be.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a lactone addition amount and a minimum exposure amount.

FIG. 2 is a graph showing a relationship between a lactone addition amount and a line width at a minimum exposure amount.

FIG. 3 is a diagram simulating cross-sectional photographs of a hole pattern when a radiation-sensitive material to which lactone is added and when a radiation-sensitive material to which lactone is not added are used.

FIG. 4 is a graph showing a relationship between a hole diameter and an exposure amount when a radiation-sensitive material to which lactone is added and when a radiation-sensitive material to which lactone is not added are used.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahisa Namiki 4-1-1 Kamikadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Koji Nozaki 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Fujitsu Co., Ltd. (72) Miwa Ozawa, Inventor 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture No. 1 Fujitsu Co., Ltd. (72) Junichi Ima 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki, Kanagawa No. 1 Inside Fujitsu Limited

Claims (9)

[Claims] 1. A base resin comprising a film-forming polymer, a photosensitive agent, and a compound represented by the general formula: (Wherein, R ₁ represents an atomic group having 2 to 30 carbon atoms; R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms,
Represents a hydroxyalkyl group of 10 or a haloalkyl group having 1 to 10 carbon atoms; n represents an integer of 2 to 8;
Represents an integer of 6. A radiation-sensitive material comprising: a lactone derivative compound of formula (I); and a solvent that dissolves the base resin, the photosensitive agent, and the lactone derivative compound. 2. The radiation-sensitive material according to claim 1, wherein the composition ratio of the lactone derivative compound is less than 50% by weight relative to the base resin. 3. A base resin comprising a film-forming polymer, a photosensitive agent, and a compound represented by the general formula: (Wherein, R and R ′ each represent hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms). A radiation-sensitive material comprising: a lactone; and a solvent that dissolves the base resin, the photosensitive agent, and the lactone. 4. The radiation-sensitive material according to claim 3, wherein the composition ratio of the lactone is 5 to 200% by weight based on 100% by weight of the composition ratio of the base resin and the photosensitive agent. Radiation-sensitive material. 5. The radiation-sensitive material according to claim 1, wherein the lactone portion of the lactone derivative compound or the lactone is: A radiation-sensitive material, which is a substance selected from the group consisting of: 6. The radiation-sensitive material according to claim 1, wherein the lactone portion of the lactone derivative compound or the lactone is opened in an aqueous alkali solution to form a hydroxy acid. Radiation-sensitive material. 7. The radiation-sensitive material according to claim 6, wherein the alkaline aqueous solution is an aqueous solution mainly containing either tetramethylammonium hydroxide or potassium hydroxide. 8. A substrate resin comprising a polymer capable of forming a film on a substrate to be processed, a photosensitive agent, and a compound represented by the general formula: (Wherein, R ₁ represents an atomic group having 2 to 30 carbon atoms; R ₂ represents hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms,
Represents a hydroxyalkyl group of 10 or a haloalkyl group having 1 to 10 carbon atoms; n represents an integer of 2 to 8;
Represents an integer of 6. A) applying a radiation-sensitive material having a lactone derivative compound and a solvent; and selectively exposing the radiation-sensitive material on the substrate to be exposed to radiation; Developing the radiation-sensitive material with an aqueous alkali solution to form a predetermined resist pattern. 9. A substrate resin comprising a polymer capable of forming a film on a substrate to be processed, a photosensitive agent, and a compound represented by the general formula: (Wherein, R and R ′ each represent hydrogen, a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, a hydroxyalkyl group having 1 to 10 carbon atoms, or a haloalkyl group having 1 to 10 carbon atoms). A step of applying a radiation-sensitive material having a lactone and a solvent; a step of selectively exposing the radiation-sensitive material on the substrate to be exposed to radiation; Forming a predetermined resist pattern by developing the resist pattern.