JP2001022069A - ArF POSITIVE TYPE PHOTO-IMAGE FORMING COMPOSITION - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance transparency, sensitivity, dry etching resistance, adhesion and resolution by using a new acrylic copolymer having a thiophene residue and an ester residue introduced into a side chain. SOLUTION: The ArF positive type photo-image forming composition contains a copolymer obtained by copolymerizing a 2-thienylalkyl (meth)acrylate and a (meth)acrylic ester and a photo-acid generating agent as essential components. The photo-acid generating agent is 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate. When an acid propagator is further contained, a proton formed from the photo-acid generating agent acts catalytically to the acid propagator and a large quantity of a new strong acid is released in geometric progression. By the catalytic actions of all the acids, ester groups such as tertiary alkyl ester groups in the acrylic copolymer cause elimination and become (meth)acrylic acid groups by accelerative degradation, accordingly sensitivity is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a composition for forming an ArF positive optical image, and more particularly to a composition for forming a positive optical image suitable for photolithography using an ArF excimer laser (193 nm).

[0002]

2. Description of the Related Art High integration of semiconductor integrated circuits has promoted a reduction in the wavelength of an exposure light source for fine processing in optical lithography. From the g-line (λ = 436 nm) and i-line (365 nm) of mercury lamps, which were the main players in mass-production exposure light sources until the mid-1990s, the wavelength has been shortened from the current main role to the KrF excimer laser (248 nm). At the beginning of the century, ArF excimer lasers with shorter wavelengths than before (193
nm) is expected to be mass-produced. Along with the shortening of the wavelength, photoresist materials have long been the main players, and have changed from the novolak / naphthoquinonediazide system to the polyvinyl phenol / chemical amplification system in the KrF generation, and have been vigorously developed and improved. Photoresist materials used for microfabrication are required to have resolution, sensitivity, dry etching resistance, adhesion, etc., but conventional photoresist materials are not compatible with alkali developing solutions using the acidity of phenolic resins. Excellent solubility and dry etching resistance due to aromatic rings in the resin have supported the performance.

[0003] However, these phenolic photoresist materials have an extremely large absorbance at 193 nm in the aromatic ring in the resin and are opaque, so that fine processing by ArF exposure is impossible. For this reason, a photoresist having an acrylic polymer as a basic skeleton has been proposed, but lacked etching resistance. To improve the etching resistance, an alicyclic group having a high effective carbon density (JP
photopolym. Sci. Technol. ; 5
439 (1992) and a naphthyl group (Jan.
Apply. Phys. 33, 7028 (199
4)) or a polynorbornene-based photoresist material having an alicyclic group in the main chain (J. Pho).
topolym. Sci. Technol. 11,4
81 (1998)). However, these photoresist materials have a problem of poor dry etching resistance and adhesion.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of these problems, and has excellent transparency, sensitivity, dry etching resistance, adhesion, and resolution. An object of the present invention is to provide a positive-type photoimage-forming composition suitable for photolithography using an excimer laser (193 nm).

[0005]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve this problem, and have found that a novel acrylic copolymer having a thiophene residue and an ester residue introduced into a side chain thereof is used as a photoacid generator. It has been found that the object can be achieved by using the compound in combination with or with an acid proliferating agent, and the present invention has been completed.

In order to achieve the above object, according to claim 1
The composition for forming an rF-positive photoimage is composed of (A) a copolymer obtained by copolymerizing 2-thenylalkyl (meth) acrylate and (meth) acrylate, and (B) a photoacid generator. And as an essential component.

By introducing a thiophene residue into the side chain of the acrylic copolymer (A), high transparency, dry etching resistance, and high adhesion to a substrate can be expected. In addition, high transparency can be expected by introducing an ester group such as a tertiary alkyl ester group into the side chain of the acrylic copolymer as the component (A). When the positive-type photoimage-forming composition of the present invention is irradiated with light, protons are generated from the photoacid generator as the component (B), and the protons catalyze the third component of the acrylic copolymer as the component (A). Since an ester group such as a secondary alkyl ester group causes a elimination reaction to become a (meth) acrylic acid group, the acrylic copolymer of the component (A) was insoluble in an alkali developing solution before the elimination reaction. However, after this elimination reaction, it becomes soluble in an alkali developing solution. This enables development using a standard alkaline developer.

As described above, a small amount of acid generated from the photoacid generator of component (B) by light irradiation serves as a catalyst,
The above-mentioned chemical reaction of the acrylic copolymer as a component is repeatedly caused to change the solubility of the acrylic copolymer in an alkali developing solution. The microscopic change of generating an acid from the photoacid generator of the component (B) becomes a macroscopic change of the solubility of the acrylic copolymer of the component (A) in an alkali developing solution through an acid catalyzed reaction. It is amplified until.

[0009] Claim 2 of the present invention is directed to Ar of claim 1.
In the F-positive photoimage forming composition, the photoacid generator (B) is 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate. The component (B), 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, easily generates a proton upon irradiation with light, and the Ar of the present invention
A latent image of an acid is formed in the F-positive photoimage forming composition.

[0010] Claim 3 of the present invention relates to (A) a copolymer obtained by copolymerizing 2-thenylalkyl (meth) acrylate and (meth) acrylate, and (B) a photoacid generator. And (C) an acid multiplying agent as essential components.

When the ArF positive-type photoimage forming composition of the present invention is irradiated with light, protons generated from the photoacid generator (B) act catalytically on the acid multiplying agent (C). Then, a large amount of a new strong acid is released from the acid proliferating agent of the component (C) in a mouse, and the tertiary alkyl ester group of the acrylic copolymer of the component (A) is catalyzed by all these acids. Such an ester group causes an elimination reaction and is acceleratedly decomposed into a (meth) acrylic acid group, thereby greatly improving the sensitivity. It is not just sensitivity that improves by incorporating an acid growth reaction. When an acid catalyst is used, there is a problem that the acid on the film surface is deactivated by a basic substance in the air. If the acid catalysis reaction on the film surface is suppressed by the deactivation of the acid, the alkali developer cannot penetrate into the inside of the film and the resolution will be reduced. However, (C)
When the acid proliferating agent as a component is used in combination, the acid proliferates in the film, so that the influence of the basic substance in the air is hardly a problem, and not only the sensitivity but also the resolution is improved.

According to a fourth aspect of the present invention, there is provided Ar
In the F-positive photoimage forming composition, (B) the photoacid generator is 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, and (C) the acid proliferating agent is a compound represented by the following formula (1). It is characterized by being.

[0013]

Embedded image

The component (B), 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, easily generates a proton upon irradiation with light, and the Ar of the present invention
A latent image of an acid is formed in the F-positive photoimage forming composition. On the other hand, when no acid is present, the acid multiplying agent of the component (C) represented by the above formula (1) has high thermal stability. But,
When heated, the acid generated from the component (B) acts catalytically on the acid multiplying agent of the component (C) represented by the above formula (1) to release a large amount of new strong acid. Due to the catalytic action of this strong acid, the ester group such as the tertiary alkyl ester group of the acrylic copolymer of the component (A) is acceleratedly decomposed by the elimination reaction to become a (meth) acrylic acid group, which greatly increases the sensitivity. improves. The acid proliferating agent of the component (C) represented by the above formula (1) is a thiophene derivative, but has a small molar extinction coefficient with respect to an ArF excimer laser (193 nm) despite having an aromatic ring, and impairs transparency. The degree is small. When the acid multiplying agent of the component (C) represented by the above formula (1) is used in combination with the acrylic copolymer of the component (A), the acid multiplying reaction efficiency is high.

[0015]

Embodiments of the present invention will be described below in detail. The acrylic copolymer of the component (A) used in the present invention is a copolymer obtained by copolymerizing 2-phenylalkyl (meth) acrylate and (meth) acrylate. The form of copolymerization of this copolymer may be a random copolymer, a block copolymer, a graft copolymer, or a combination thereof, and is not particularly limited. Among them, a random copolymer can be preferably used.

As the 2-thenylalkyl (meth) acrylate used in the present invention, a linear and / or branched alkyl (meth) acrylate having 1 to 5 carbon atoms can be preferably used. Acrylate, 2-Cenylmethyl acrylate, 2-Cenylethyl methacrylate, 2-Cenylethyl acrylate, 2-Cenylpropyl methacrylate, 2-Cenylpropyl acrylate, 2-Cenyln-butyl methacrylate, 2- Chenyl n-butyl acrylate, 2-Chenyl i-butyl methacrylate, 2-Chenyl i-butyl acrylate, 2-Chenyl n-pentyl methacrylate, 2-Cenyl n-pentyl acrylate, 2-Cenyl i-pentyl methacrylate, 2 -Chenyl i-pe Chill acrylate, and the like, and these two or more thereof. 2-Cenylmethyl methacrylate and 2-Cenylmethyl acrylate can be more preferably used.

The method for synthesizing the 2-phenylalkyl (meth) acrylate used in the present invention is not particularly limited.
For example, as an example of synthesizing 2-thienylmethyl (meth) acrylate, specifically, an example of synthesizing 2-thienylmethyl methacrylate (TMMA) by reacting 2-thienylmethanol and methacrylic acid chloride at room temperature in methylene chloride. Can be mentioned.

(Meth) of the other monomer used in the present invention
The acrylic ester is an acrylic ester and / or a methacrylic ester, and may be a combination of both in an arbitrary ratio. Representative examples of the (meth) acrylic acid ester preferably used in the present invention are shown in FIGS. A-1, A-2, A-3, shown in FIG.
A-4, A-5, A-6, A-7, A- shown in FIG.
8, (meta) of A-9, A-10, A-11 and A-12
Acrylic esters and mixtures of two or more of them can be used, and among them, tertiary butyl (meth) acrylates of A-1 and A-3 can more preferably be used.

When copolymerizing 2-ethenylalkyl (meth) acrylate and (meth) acrylate, one or more monomers selected from acrylamide and other various acrylic monomers copolymerizable therewith are used. The copolymer can be copolymerized within a range that does not impair the effects of the present invention.

The molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the acrylic copolymer (A) used in the present invention are not particularly limited. However, the molecular weight (M
w) is usually preferably 3,000 to 1,000,000, more preferably 4,000 to 500,000,
Particularly, 5,000 to 100,000 is preferable. If the molecular weight is less than 3,000, it is difficult to form a film.
If it exceeds 000, film formation may be difficult.

The molecular weight distribution (Mw / Mn) is preferably as small as possible, usually about 1 to 10, more preferably about 1 to 5, and particularly preferably about 1 to 4. If the molecular weight distribution (Mw / Mn) exceeds 10, the strength of the film may be reduced.

In the present invention, the molar ratio of 2-ethenylalkyl (meth) acrylate to (meth) acrylate may be in the range of 1 to 50:99 to 50, preferably 5 to 40:95 to 60, More preferably, 10 to 3
0: 90 to 70. In the present invention, a homopolymer using only 2-Chenylalkyl (meth) acrylate cannot be used because it is soluble in an alkaline developer, and a homopolymer using only (meth) acrylate is The dry etching resistance and adhesion are poor, which is not preferable.

FIG. 3 shows a synthesis example of the acrylic copolymer of the component (A) used in the present invention. FIG. 3 shows raw material monomers, reaction formulas, and chemical structures of intermediate products and products when synthesizing the acrylic copolymer as the component (A).

As shown in FIG. 3, in this example, first, 2-thienylmethanol (a) and methacrylic acid chloride (b) are reacted at room temperature in methylene chloride to give 2-thienylmethyl methacrylate (TMMA) ( c) is synthesized. Next, the TMMA (c) and tertiary butyl methacrylate (tBMA) (d) were mixed at 67 ° C. with THF as a solvent and AIBN as an initiator.
Radical copolymerization was carried out for 4 hours to obtain an acrylic copolymer (e) of component (A) containing TMMA units (20 mol%) and tBMA units (80 mol%) (Mw = 5.2 × 10 4
⁴ , Mw / Mn = 3.9, Tg = 101 ° C.).

FIG. 4 shows the acrylic copolymer (e) synthesized as described above (m = 0.2, n = 0.8 in the figure).
The transmittance (%) to light (wavelength 193 nm to 440 nm) of the film was measured (polymer concentration; 1% by weight in solvent; film thickness; 40 nm). For comparison, FIG. 4 also shows the measurement results of a film of the phenolic photoresist material (f) and a film of the homopolymer (g) using only tertiary butyl methacrylate.

FIG. 4 shows that the acrylic copolymer (e) exhibits high transparency to light of 193 nm.
Further, the homopolymer (g) using only tertiary butyl methacrylate has high transparency to light of 193 nm, but the phenolic photoresist material (f) has 1
It turns out that transparency is low with respect to light of 93 nm.

As the photoacid generator (B) used in the present invention, conventionally known photoacid generators can be used. Representative examples of conventionally known photoacid generators are shown in FIGS. The photoacid generators B-1, B-2, B-3, B-4, B- shown in FIG.
5, the photoacid generators B-6, B-7, B-8 shown in FIG.
B-9, B-10, B-11, or a combination of two or more of them can be preferably used, and among them, 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate of B-7 can be more preferably used.

The compounding amount of the component (B) is 1 to 20% by weight based on the total composition for forming an ArF positive-type photoimage of the present invention.
Is more preferable, more preferably 2 to 15% by weight, and particularly preferably 3 to 10% by weight. If the amount is less than 1% by weight, the amount of protons generated upon light irradiation becomes insufficient, and
If the content is more than 10% by weight, transparency may be adversely affected.

As the acid proliferating agent of the component (C) used in the present invention, conventionally known ones can be used. FIGS. 7 and 8 show typical examples of conventionally known acid proliferating agents. The acid proliferating agents C-1, C-2, C-3, C-4, C-5, and C- shown in FIG.
6, C-7, C-8, acid proliferating agents C-9, C shown in FIG.
-10, C-11, C-12, C-13, or a combination of two or more of them can be preferably used, and among them, the acid proliferating agent of C-1 represented by the formula (1) is more preferable. Can be used.

FIG. 9 shows the chemical structural formulas of other known acid-proliferating agents 1, 2 and 3, and these acid-proliferating agents 1, 2 and 3.
And 3 decompose when heated in the presence of an acid catalyst to form a strong acid (p-toluenesulfonic acid), which acts as an autocatalyst, so that the strong acid (p-toluenesulfonic acid) A reaction formula showing that the compound is formed is shown below.

The compounding amount of the acid multiplying agent (C) is 1 to 3 with respect to the whole composition for forming an ArF positive-type photoimage of the present invention.
It is preferably 0% by weight, more preferably 2 to 20% by weight, particularly preferably 3 to 10% by weight. If it is less than 1% by weight, the efficiency of the acid multiplication reaction is low, and if it exceeds 30% by weight, the transparency may be adversely affected.

In FIG. 10, the conversion rate (%) is plotted on the ordinate and the heating time (min.) On the abscissa, and the acid multiplying agent represented by the above formula (1) is dissolved in the solvent CDCl ₃ (deuterated chloroform). When heated to 100 ° C. with [acid catalyst TsOH (p-toluenesulfonic acid) 14 mol% and the same acid catalyst 0 mol%
About the case of). Also, in FIG.
When the acid proliferating agent is heated in the presence of a p-toluenesulfonic acid catalyst, it is decomposed to generate a strong acid (sulfonic acid having a thiophene group), and this strong acid acts as an autocatalyst. ) Is a reaction formula showing that mouse-generated) is generated by mouse.

As shown in FIG. 10, when p-toluenesulfonic acid (TsOH) is not added, the acid multiplying agent of the above formula (1) does not decompose even when heated for 120 minutes, and has good thermal stability. However, when TsOH is added in an amount of 14 mol%, the sulfonic acid having a thiophene group of a strong acid is generated by heating for about 60 minutes, and the generated sulfonic acid acts as an autocatalyst. The sulfonic acid is released rapidly in a large amount by the mouse.

FIG. 11 shows the acrylic copolymer (e) of the component (A) synthesized as described above (where m =
0.2, n = 0.8) (insoluble in alkaline developer)
In contrast, a composition obtained by adding 5% by weight of 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate as a photoacid generator as the component (B) was added to the composition represented by the above formula (1) as an acid multiplying agent as the component (C). 0% by weight, 5% by weight, 10% by weight,
The results of a photosensitivity test of the composition containing 20% by weight are shown [horizontal axis: ArF excimer laser (193 nm)].
Exposure (mJ / cm ² ), vertical axis: relative film thickness].

FIG. 11 shows that when light is irradiated (hν), protons (H ⁺ ) are generated from the photoacid generator of the component (B), and when heated (加熱), the protons (H ⁺ ) are converted to (H ⁺ ). C) acts catalytically on the acid multiplying agent of component
A large amount of a sulfonic acid having a thiophene group of a new strong acid is released from the acid proliferating agent of the component (C) in a large amount, and the tertiary butyl of the acrylic copolymer (A) is catalyzed by all these acids. A reaction formula showing that an ester group is rapidly decomposed into a (meth) acrylic acid group is shown.

When light is irradiated (hν), protons (H ⁺ ) are generated from the photoacid generator of the component (B), and an acid latent image is formed. When heated (△), this proton (H
⁺ ) Catalytically acts on the acid proliferating agent of component (C), and a large amount of a sulfonic acid having a thiophene residue of a new strong acid is released from the acid proliferating agent of component (C) in a mouse manner, The tertiary butyl ester group of the acrylic copolymer of the component (A) is rapidly decomposed into a (meth) acrylic acid group by the catalytic action of all these acids, and the acrylic copolymer of the component (A) is decomposed. The combination (e) becomes soluble in an alkali developing solution. From FIG. 11, the acid proliferating agent (AA) of the component (C) is shown.
It can be seen that the sensitivity is greatly improved by increasing the amount of added.

FIGS. 12A to 12E show the ArF of the present invention.
1 illustrates one embodiment of a process for forming an image using a positive-type photoimageable composition. Step (a): A solution of the ArF positive photoimage forming composition of the present invention is coated on a silicon wafer.

Step (b): After coating, 100
Pre-bake at 60 ° C. for 60 seconds to form a polymer film.

Step (c): Then, using a photomask,
Exposure is performed with a Hg-Xe lamp (wavelength: 313 nm).
A small amount of protons (H ⁺ ) are generated from the photoacid generator (B). Then, an acid latent image (H ⁺ ) is formed on the exposed portion. At this time, the tertiary butyl ester group of the acrylic copolymer (e) (m = 0.2, n = 0.8 in the figure) as the component (A) has not been decomposed.

Step (d): Next, post-baking is performed at 100 ° C. for 90 seconds. By this post-baking, a very small amount of acid generated from the photoacid generator of the component (B) serves as a trigger to release a large amount of new strong acid from the acid proliferating agent of the component (C) and to multiply the acid. The tertiary butyl ester group of the acrylic copolymer (A) is rapidly decomposed into a (meth) acrylic acid group (soluble in an alkali developing solution) by the catalytic action of all these acids.

Step (e); 3% by weight (CH ₃ )
₄ N ⁺ OH - is developed to form an image using the ^{(tetramethylammonium} hydroxide) solution.

Since the present invention is not limited to the above embodiment, various modifications can be made without departing from the spirit of the appended claims.

[0043]

The present invention will be described below with reference to examples. Of course, the present invention is not limited to the embodiments described below. (Example 1) 2-thienyl methanol and methacrylic acid chloride were reacted in methylene chloride to obtain 2-thienylmethyl methacrylate (TMMA). In addition, TMM
A and tertiary butyl (meth) acrylate (tBM)
A) Acrylic copolymer of component (A) (Mw = 52,000, Mw / Mn = 3.) Used in the present invention by radical co-assembly of A) with AIBN (initiator) in THF (solvent).
9) was synthesized with a yield of 71%. The transparency of the acrylic copolymer film of the component (A) was measured by spin-coating a 1% by weight cyclohexanone solution of the copolymer on a quartz substrate to form a film. As a result of the measurement, 198
It exhibited high transparency of 75% or more for nm light.

Component (C), the acid multiplying agent represented by the above formula (1) (5 to 20% by weight) / (A) component acrylic copolymer (85% by weight) / (B) component light A of the present invention comprising an acid generator (4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate) (5% by weight)
An rF positive-type photoimageable composition was prepared.

The sensitivity characteristics of the ArF-positive optical image forming composition of the present invention are as follows. A film having a thickness of 1.2 μm is prepared.
After irradiation with light from a Xe lamp (wavelength 313 nm), 10
The film was heated at 0 ° C., developed with a 3% by weight aqueous solution of tetramethylammonium hydroxide for 10 minutes, and evaluated by measuring the thickness of the obtained film. It has been found that increasing the amount of the acid-proliferating agent (C) added to 0 to 20% by weight significantly improves the sensitivity sequentially.

The ArF-positive optical image forming composition of the present invention exhibited excellent adhesion to a quartz substrate, a silicon wafer, and the like, and did not cause peeling or cracking during development.

[0047]

The acrylic copolymer of the component (A) used in the composition for forming an ArF positive-type photoimage according to claim 1 of the present invention has an acrylic resin excellent in transparency as a backbone and has a wavelength of 200 nm or less. It has a side chain of a chemical structure excluding conjugated double bonds having a high molar extinction coefficient in the region.

This acrylic copolymer has a high transparency of 75% or more for light of 193 nm. In the design of the side chain, sensitivity and resolution are improved by adopting a structure in which a tertiary butyl ester group of (meth) acrylic acid ester causes an elimination reaction by an acid to become (meth) acrylic acid group. It can also satisfy the applicability to a standard alkaline developing solution, and balance the problem peculiar to the polymer containing a (meth) acrylate group structure, which easily causes peeling and cracking during development, with the high polarity of the other thiophene ester group. By taking this, high dry etching resistance and high adhesion without peeling or cracks can be obtained.

In the exposed portion of the ArF-positive photoimage forming composition according to claim 1 of the present invention, the acid generated from the photoacid generator as the component (B) acts catalytically by heating after exposure, For example, a tertiary butyl ester group of the (meth) acrylic acid ester undergoes an elimination reaction to become a (meth) acrylic acid group and becomes alkali-soluble, whereby a positive pattern can be formed.

In the ArF-positive photoimage forming composition according to claim 2 of the present invention, the photoacid generator as the component (B) is 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate. The component (B), 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, easily generates a proton upon irradiation with light to form a latent image of an acid.

The ArF-positive photoimage forming composition according to claim 3 of the present invention comprises the acrylic copolymer of the component (A) and the photoacid generator of the component (B) which generates protons upon irradiation with light. Since an acid multiplying agent is further added as a component (C) in addition to the agent, the proton generated from the photoacid generator of the component (B) upon irradiation with light is used as a catalyst for the acid multiplying agent of the component (C). , A large amount of new strong acid is released from the acid proliferating agent of the component (C) in a ratative manner, and the catalysis of all these acids causes the (meth) acrylic acid ester to have a tertiary butyl ester group, for example. Causes a elimination reaction and is acceleratedly decomposed into (meth) acrylic acid groups, so that the sensitivity is greatly improved.

When an acid catalyst is used, the acid on the film surface is deactivated by the basic substance in the air. When the acid catalyst reaction on the film surface is suppressed by the deactivation of the acid, the alkali developing solution is removed from the inside of the film. There is a problem that the resolution cannot be reduced due to infiltration into the film, but the acid multiplying agent of the component (C) causes the acid to multiply in the film, so that the influence of the basic substance in the air is hardly a problem. In addition, the resolution as well as the sensitivity is improved.

In the ArF-positive photoimage forming composition according to claim 4 of the present invention, (B) the photoacid generator is 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, and (C) the acid multiplying agent is It is a compound represented by the formula (1). The component (B), 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, easily generates a proton upon irradiation with light to form a latent image of an acid. If no acid is present, the acid multiplying agent of component (C) represented by the above formula (1) has high thermal stability. But,
When heated, the acid generated from the component (B) acts catalytically on the acid multiplying agent of the component (C) represented by the above formula (1) to release a large amount of new strong acid. Due to the catalytic action of this strong acid, for example, a tertiary butyl ester group of the (meth) acrylic ester of the acrylic copolymer as the component (A) is rapidly decomposed into a (meth) acrylic acid group by a elimination reaction. Sensitivity is further improved, and productivity can be improved.

The acid proliferating agent of the component (C) represented by the above formula (1) is a thiophene derivative, but has a small molar extinction coefficient with respect to an ArF excimer laser (193 nm) despite having an aromatic ring, and has high transparency. The degree of inhibition is small. When the acid multiplying agent of the component (C) represented by the above formula (1) is used in combination with the acrylic copolymer of the component (A), the acid multiplying reaction efficiency is high.

The composition for forming an ArF positive-type photoimage according to claims 1 to 4 of the present invention is excellent in transparency, sensitivity, dry etching resistance, adhesion, and resolution.
It can be used not only as a positive ArF photoresist suitable for photolithography using an ArF excimer laser (193 nm) but also useful in the fields of printing and electronics. It is applicable to scanning recording by laser, hologram recording, etc., and has great utility.

[Brief description of the drawings]

FIG. 1 is a chemical structure of a typical example of a (meth) acrylic ester as one of raw material monomers when synthesizing an acrylic copolymer of the component (A) used in the ArF positive-type photoimage forming composition of the present invention. FIG.

FIG. 2 shows another typical example of (meth) acrylic acid ester as one of the raw material monomers when synthesizing the acrylic copolymer of the component (A) used in the ArF positive-type photoimage forming composition of the present invention. It is explanatory drawing which shows a chemical structure.

FIG. 3 shows raw material monomers, reaction formulas, and chemical structures of intermediate products and products when synthesizing the acrylic copolymer of the component (A) used in the ArF-positive photoimage forming composition of the present invention. FIG.

FIG. 4 shows light (wavelength 193 nm to 44 nm) of a film of a synthetic acrylic copolymer and a polymer for comparison.
11 is a graph showing the results of measuring the transmittance (%) with respect to 0 nm).

FIG. 5 is an explanatory view showing a chemical structure of a typical example of a photoacid generator as the component (B) used in the ArF positive-type photoimage forming composition of the present invention.

FIG. 6 is an explanatory view showing the chemical structure of another typical example of the photoacid generator as the component (B) used in the ArF-positive photoimage forming composition of the present invention.

FIG. 7 is an explanatory view showing the chemical structure of a typical example of the acid multiplying agent of the component (C) used in the ArF positive-type photoimage forming composition of the present invention.

FIG. 8 is an explanatory view showing the chemical structure of another typical example of the acid-proliferating agent of the component (C) used in the ArF-positive photoimage forming composition of the present invention.

FIG. 9 is an explanatory diagram showing a reaction in which a strong acid is generated when an acid proliferating agent of the component (C) is heated in the presence of an acid, and the strong acid acts as an autocatalyst to be rapidly decomposed to generate a large amount of a strong acid. It is.

FIG. 10 is a graph showing the decomposition behavior when the acid proliferating agent (C) is heated to 100 ° C. in a solvent in the presence of a strong acid and in the absence of a strong acid, and a strong acid is generated when heated in the presence of an acid. FIG. 4 is an explanatory view showing a reaction in which the strong acid acts as an autocatalyst to rapidly decompose the component (C) and generate a large amount of a strong acid.

FIG. 11 is a graph showing the results of testing the photosensitivity of the ArF-positive optical image forming composition of the present invention, and shows that when irradiated with light, the photoacid generator (B) converts protons (H ⁺ ).
Is produced, and when heated, this proton (H ⁺ ) catalyzes the acid proliferating agent of the component (C) to release a large amount of a new strong acid through the mouse. It is explanatory drawing which shows the reaction which shows that the tertiary butyl ester residue of the acrylic copolymer of (A) component is acceleratedly decomposed and becomes a (meth) acrylic acid group.

FIG. 12 (A) shows A of the present invention on a silicon wafer.
a step of coating the rF positive type optical image forming solution,
(B) is a step of forming a polymer film by pre-baking at 100 ° C. for 60 seconds after coating;
Is a Hg-Xe lamp (wavelength 313) using a photomask.
(d) exposure at 100 ° C.
(E) is an explanatory view showing a step of forming an image by developing using a 3% by weight aqueous solution of tetramethylammonium hydroxide.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/027 H01L 21/30 502R F-term (Reference) 2H025 AA00 AA01 AA02 AA09 AA14 AB03 AB16 AB17 AB20 AC08 AD03 BE00 BE07 BG00 CC20 FA03 FA10 FA12 FA17 4J002 BG041 BG051 BG071 EB106 EV246 EV247 EV296 EV307 EV347 FD206 FD207 GP03 4J100 AL03Q AL08P AL08Q BA06Q BA11Q BC04Q BC53Q BC83P CA04 DA36 DA62 JA38

Claims (4)

[Claims] Claims: 1. An essential component comprising (A) a copolymer obtained by copolymerizing 2-thenylalkyl (meth) acrylate and (meth) acrylate, and (B) a photoacid generator. An ArF positive-type photoimage forming composition, comprising: 2. The ArF positive-type photoimage forming composition according to claim 1, wherein the photoacid generator (B) is 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate. 3. A copolymer obtained by copolymerizing (A) 2-thenylalkyl (meth) acrylate and (meth) acrylate, (B) a photoacid generator, and (C) an acid ArF characterized by containing a proliferating agent as an essential component.
A positive-type photoimage-forming composition. 4. The method according to claim 1, wherein (B) the photoacid generator is 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate, and (C) the acid proliferating agent is a compound represented by the following formula (1). The ArF according to claim 3,
A positive-type photoimage-forming composition. Embedded image