JPS622304B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD This invention relates to photoresist compositions. More specifically, conjugated diene polymers or copolymers (hereinafter simply referred to as conjugated diene polymers)
The present invention relates to a photoresist composition comprising a cyclized product of the present invention, a photocrosslinking agent soluble in an organic solvent, a storage stabilizer, and a specific compound. Integrated circuit manufacturing technology has made remarkable progress, and the degree of integration has recently been increasing at an annual rate of twice as much. Therefore, there is a strong demand for improvements not only in manufacturing technology but also in the equipment and peripheral materials used, and in the photoresist field,
There is a particular need for compositions that are easy to handle and have high resolution. Currently, in the production of integrated circuits, a diazide compound-polyisoprene cyclized compound is used as a negative photoresist composition, and a quinone diazide compound-novolak resin is used as a positive photoresist composition. The former is superior in terms of handling, but its resolution is low, especially in substrates with surfaces with high reflectance, and the latter is superior in resolution, but it is difficult to handle. That is, the diazide compound-polyisoprene cyclized photoresist composition contains aluminum,
On a highly reflective substrate such as chrome, the light reflected from the substrate surface during exposure wraps around the area that you do not want to expose (this development is called halation).
Expose that part to light. This development is particularly noticeable in the step structure portions of the substrate, and the resolution is reduced due to the formation of hardened portions called whiskers. The above halation development will be explained with reference to the attached drawings. In the drawings, 1 is a mask, 2 is a mask light-shielding part, 3 is a mask light-transmitting part, 4 is incident light,
5 is reflected light, 6 is a photoresist composition, and 7 is a slope in the step structure of the substrate 8. The light 4 that has passed through the light-transmitting part 3 of the mask and entered the photoresist composition 6 is reflected by the inclined surface 7 of the substrate 8 and goes under the mask light-shielding part 2, thereby exposing the photoresist composition in that part. That is, areas of the photoresist composition that are not desired to be exposed to light are exposed, resulting in a decrease in resolution. In order to improve this drawback,
A method has also been proposed in Japanese Patent Application Laid-Open No. 53-70812. These techniques attempt to improve the above-mentioned drawbacks by reducing the light transmittance of the photoresist composition coating by adding a light-absorbing material to the photoresist composition. According to this method, the light that is reflected from the substrate surface and transmitted through the photoresist composition coating is absorbed by the light-absorbing material and is rapidly attenuated, resulting in a decrease in resolution due to the light going around to areas that are not desired to be exposed. can be prevented. But on the other hand,
The unavoidable reduction in adhesion of the photoresist composition to the substrate was a major drawback of the prior art. The present inventors studied ways to improve the above drawbacks, and developed a photoresist composition based on a diazide compound and a conjugated diene polymer cyclized product with the general formula Ar-N=N-NH-Ar' (where Ar, Ar ′ are the same or different aromatic groups), high-resolution images can be obtained even when using a substrate with a highly reflective surface, and adhesive It was discovered that there was no decrease in sexual performance, and the present invention was completed based on this finding. The cyclized product of the conjugated diene polymer used in the present invention is a cyclized product of a polymer or copolymer having a unit represented by the following formula in the polymer chain.

[Formula] or

[Formula] [In the formula, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ , and R ₁₀ are the same or different hydrogen atoms, alkyl groups (especially lower alkyl groups, such as methyl, ethyl, propyl), or aryl groups. be〕. A specific example is cis-1,
4-butadiene unit, trans-1,4-butadiene unit, cis-1,4-isoprene unit, trans-1,4-isoprene unit, cis-1,4-
Pentadiene unit, trans-1,4-pentadiene unit, 1,4-2-phenylbutadiene unit, 1,2-butadiene unit, 3,4-isoprene unit, 1,2-pentadiene unit, 3,4-2
- Phenylbutadiene units, and unsaturated monomer units that can be copolymerized with these conjugated diene units include vinyl aromatic compound units such as styrene and α-methylstyrene, and olefin units such as ethylene, propylene, and isobutylene. can be mentioned. As the organic solvent-soluble photocrosslinking agent used in the present invention, azide-based photosensitive substances, such as 4,
4'-Diazidostilbene, p-phenylenebisazide, 4,4'-diazidobenzophenone, 4,
4'-Diazidophenylmethane, 4,4'-diazidochalcone, 2,6-bis(4'-azidobenzal)
Cyclohexanone, 2,6-bis(4'-azidobenzal)-4-methylcyclohexanone, 4,
4'-diazidophenyl, 4,4'-diazide-3,
3'-dimethyldiphenyl, 2,7-diazidefluorene, etc. can be used. However, the photocrosslinking agent is not limited to the above-mentioned photocrosslinking agents, and any photocrosslinking agent that is effective in combination with the cyclized product used in the present invention can be used. These photocrosslinking agents are 0.1 to 10
It is used by adding % by weight, preferably 1 to 3
It is used by adding % by weight. Storage stabilizers are also not particularly limited, but include hydroxy aromatic compounds such as hydroquinone, methoxyphenol, and pt-butylcatechol; quinones such as benzoquinone, p-torquinone, and p-xyquinone; phenyl-α-naphthylamine; ，
Amines such as p'-diphenylphenylenediamine, dilaurylthiodipropionate, 4,4'-
Thiobis(6-t-butyl-3-methylphenol, 2,2'-thiobis(4-methyl-6-t-butylphenol), 2-(3,5-di-t-butyl-4-hydroxyanilino) )-4,6-bis(N-octylthio)-s-triazine, etc. can be used. A photoresist composition comprising a cyclized product of the above-mentioned conjugated diene polymer, a photocrosslinking agent, and a storage stabilizer. The compounds represented by the general formula Ar-N=N-NH-Ar' (wherein Ar and Ar' are the same or different aromatic groups) include Ar,
Compounds in which Ar′ is a group selected from phenyl, methylphenyl, dimethylphenyl, ethylphenyl, nitrophenyl, naphthyl, methylnaphthyl, dimethylnaphthyl, ethylnaphthyl, and nitronaphthyl are preferred, such as Diazoaminobenzene, 4,4'-dimethyldiazoaminobenzene, 2,4'-dimethyldiazoaminobenzene, 2,4-dimethyldiazoaminobenzene,
4,4'-diethyldiazoaminobenzene, 4,
4'-dinitrodiazoaminobenzene, 1,1'-diazoaminonaphthalene, 4,4'-dimethyl-1,
Examples include 1'-diazoaminonaphthalene, 4,4'-diethyl-1,1'-diazoaminonaphthalene, and 4,4'-dinitro-1,1'-diazoaminonaphthalene, which are particularly easily available. Among them, diazoaminobenzene and 4,4'-dimethyldiazoaminobenzene are preferred. These are preferably added in an amount of 0.1 to 10% by weight, particularly preferably 1% by weight, based on the cyclized product of the conjugated diene copolymer.
~5% by weight is used. If the amount added is less than 0.1% by weight, the effect of the addition is small, and if it is added in excess of 10% by weight, a defect may occur in that the adhesion of the photoresist composition to the substrate is reduced. Sensitizers can also be added to the photoresist compositions of the present invention. Examples of the sensitizer include benzophenone, anthraquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, 2-methylanthraquinone, benzanthrone, violanthrone,
Carbonyl compounds such as 9-anthraldehyde, benzyl, p,p'-tetramethyldiaminobenzophenone, chloranil, aromatic hydrocarbons such as anthracene and chrysene, nitrobenzene, p-
dinitrobenzene, 1-nitronaphthalene, p-
Nitrodiphenyl, 2-nitronaphthalene, p-
Nitrodiphenyl, 2-nitrofluorene, 5-
Nitro compounds such as nitroacenaphthene, nitroaniline, 2-chloro-4-nitroaniline,
Examples include nitrogen compounds such as 2,6-dichloro-4-nitroaniline, 5-nitro-2-aminotoluene, and tetracyanoethylene, and sulfur compounds such as diphenyl disulfide. When the photoresist composition of the present invention is used, it is possible to prevent a decrease in resolution due to halation on a highly reflective substrate having a stepped structure, and no decrease in adhesion occurs on a silicon oxide film. That is, the present invention can improve the deterioration in adhesion, which is an unavoidable drawback of conventional antihalation techniques. Furthermore, the photoresist composition of the present invention has an excellent property that there are few pinholes on the resist surface when etching is performed after development and heat treatment. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples; however, the present invention is not limited to these Examples unless the gist of the invention is exceeded. Comparative Example 1 cis-1,4-polyisoprene cyclized product (residual double bond amount 26%, [η] ³⁰ °C xylene = 0.72) 11.00 g
0.22 g of 2,6-bis(4'-azidobenzal)cyclohexanone as a photocrosslinking agent and 2,2'-methylenebis(4-methyl-6-t) as a storage stabilizer.
-butylphenol) 0.11g, 4,4'-thiobis(2,6-di-t-butylphenol) 0.11g,
88.6 g of xylene was added to prepare a photoresist. The photoresist thus prepared was coated with a thickness of 0.2
A 1.0 μm thick aluminum layer is deposited on a silicon wafer with a 0.6 μm step structure.
It was coated by rotating using a spinner so that
Then, it was dried for 15 minutes in a circulating constant temperature bath at 80℃.
Using an ultra-high-pressure mercury lamp, the image was printed at a light intensity of 50 W/m ² by exposure through a resolution test chart chrome mask manufactured by Toppan Printing Co., Ltd. After immersion development for 1 minute using Kodatsu Microresist Developer manufactured by Eastman Kodak Co., Ltd., acetic acid-n-
Rinse with butyl for 1 minute and observe the printed image. The results are shown in Table 1. 90 with an exposure time of 2.5 seconds
% or more, and the resolution on flat areas is
The length of the photosensitive area was 2.6 μm, but the length of the photosensitive area became more than 7 μm due to the degree of light shielding at the stepped portion. Note that the length of the photosensitive area is the actual length of the photosensitive area by the light 5 measured from the slope 7 in the attached drawing.

[Table] Area.
Next, in Experiment No. 4, an image was printed in the same manner as Experiment No. 1, using a silicon wafer coated with a 0.7 μm silicon thermal oxide film instead of the silicon wafer on which the aluminum layer was vapor-deposited. Then, it was heat-treated in a circulating constant temperature bath at 150°C for 30 minutes in nitrogen, and then treated with an etchant of HF (49% aqueous solution) / NH ₄ F (40% aqueous solution) / H ₂ O = 1/6/10 (volume ratio). , etched for 30 minutes at 25°C. At this time, side etching (a phenomenon in which the area under the resist film is etched due to the etchant wrapping around) is
It was 3.0 μm. Comparative Example 2 cis-1,4-polyisoprene cyclized product (residual double bond amount 26%, [η] ³⁰ °C xylene = 0.72) 11.00 g
0.22 g of 2,6-bis(4'-azidobenzal)cyclohexanone as a photocrosslinking agent and 2,2'-methylenebis(4-methyl-6-t) as a storage stabilizer.
-butylphenol) 0.11g, 4,4'-thiobis(2,6-di-t-butylphenol) 0.11g,
0.55 oil yellow as an antihalation agent
g and 88.1 g of xylene were added to prepare a photoresist. Images were formed using the photoresist thus prepared in the same manner as in Comparative Example 1, and the results shown in Table 2 were obtained by observing the printed images. By increasing the exposure time to 5.0 seconds, we were able to increase the residual film rate to over 90%. The resolution on a flat area is
The length of the photosensitive area due to the wraparound of light at the stepped portion was 2.6 μm.

[Table] Next, as experiment number 8, a silicon wafer with a silicon thermal oxide film was used, and in the same manner as in comparative example 1 (experiment number 4), HF (49% aqueous solution) / NH ₄ F (40% aqueous solution) )/H ₂ O = 1/6/10 (capacity ratio) etching.
The side etch was 5.0 μm. Although the effect of so-called halation caused by the wraparound of light has been reduced, the adhesion has deteriorated and side etching has become larger when etching the silicon oxide film. Examples 1 and 3 cis-1,4-polyisoprene cyclized product (residual double bond amount 26%, [η] ³⁰ °C xylene = 0.72) 11.00 g
0.22 g of 2,6-bis(4'-azidobenzal)cyclohexanone as a photocrosslinking agent and 2,2'-methylenebis(4-methyl-6-t) as a storage stabilizer.
-butylphenol) 0.11g, 4,4'-thiobis(2,6-di-t-butylphenol) 0.11g,
A photoresist was prepared by adding a predetermined amount of diazoaminobenzene and a predetermined amount of xylene as antihalation agents. Using the photoresist prepared in this way, an image was formed on a silicon wafer on which aluminum was vapor-deposited in exactly the same manner as in Comparative Examples (Experiment Nos. 1 to 3), and the baked image was observed, and the results shown in Table 3 were obtained. . In Example 1, the residual film rate was 90% or more with an exposure time of 4.0 seconds, the resolution on the flat part was 2.2 μm, and the length of the exposed area due to the wraparound of the light at the stepped part was 1 to 2 μm.
It was m. In addition, in Example 2, the residual film rate was over 90% with an exposure time of 5.0 seconds, and the resolution on the flat area was 2.2μ.
m, the length of the photosensitive area due to the wraparound of light at the stepped portion was 1 μm or less.

[Table] As Experiment No. 13, the photoresist composition of Example 2 was used and a silicon thermal oxide film was etched in the same manner as Comparative Example 1 (Experiment No. 4). The sex was good. Examples 3 and 4 Photoresists were prepared in exactly the same manner as in Examples 1 and 2, except that 4,4'-dimethyldiazoaminobenzene was used instead of diazoaminobenzene. Using the photoresist prepared in this way, in the same manner as in Comparative Example 1 (experiment numbers 1 to 3),
The image was printed onto a silicon wafer coated with aluminum. The results are shown in Table 4, and good images with high resolution were obtained. As Experiment No. 18, a silicon thermal oxide film was etched using the photoresist of Example 4 in exactly the same manner as Comparative Example 1 (Experiment No. 4), and the side etching was 3.0 μm, indicating good adhesion.

[Table] Examples 5 and 6 cis-1,4-polybutadiene cyclized product (residual double bond amount 34%, [η] ³⁰ °C xylene = 0.51) 14.00 g
0.42 g of 2,6-bis(4'-azidobenzal)-4-methylcyclohexanone as a photocrosslinking agent,
As a storage stabilizer, 2,2'-methylenebis(4-ethyl-6-t-butylphenol) 0.14g, 6-
(4-hydroxy-3,5-di-t-butylanilino)-2,6-bisoctylthio-1,3,5
- 0.14g of triazine, specified amount of xylene, and 1,
A predetermined amount of 1'-diazoaminonaphthalene was added to prepare a photoresist. The photoresist thus prepared was coated with a thickness of 0.2μ.
A silicon wafer having a step structure of 0.6 .mu.m on which an aluminum layer of 1.0 m was deposited was spin-coated using a spinner so that the film thickness was 1.0 .mu.m. Then, it was dried for 15 minutes in a circulating constant temperature bath at 80℃, and then printed using an ultra-high pressure mercury lamp at a light intensity of 50W/ ^m2 .
The image was printed by exposure through a resolution test chart chrome mask manufactured by Co., Ltd. 210ml of n-heptane,
After immersion development for 1 minute using a developer consisting of 90 ml of decalin and 0.27 g of sorbitan monooleate,
After rinsing with n-butyl acetate for 1 minute, the printed image was observed. The results are shown in Table 5. As shown in Table 5, good images with high resolution were obtained. Experiment number 22 using the photoresist of Example 6
When a silicon wafer with an image was heat-treated in nitrogen at 150°C for 30 minutes in a circulating constant temperature bath, it was etched with phosphoric acid, and good results with few pinholes were obtained.

[Table] Example 7 A photoresist was prepared in exactly the same manner as in Examples 1 and 2, except that 0.66 g of 4,4'-dinitrodiazoaminobenzene was used instead of diazoaminobenzene. Using the photoresist thus prepared, an image was printed on a silicon wafer on which aluminum had been deposited in the same manner as in Comparative Example 1 and (Experiment Nos. 1 to 3). The results are shown in Table 6, and good images with high resolution were obtained. Using this photoresist in Experiment No. 25, a silicon thermal oxide film was etched in exactly the same manner as in Comparative Example 1 (Experiment No. 4), and the side etch was 3.0 μm, indicating good adhesion.

[Table] Examples 8 to 10 Photoresists were prepared in exactly the same manner as in Examples 1 and 2, except that the compounds shown in Table 7 were used instead of diazoaminobenzene. Using the photoresist prepared in this way, in the same manner as in Comparative Example 1 (experiment numbers 1 to 3),
The image was printed onto a silicon wafer coated with aluminum. The results are shown in Table 7, and good images with high resolution were obtained. Further, when the silicon oxide film was etched in the same manner as in Comparative Example 1 (Experiment No. 4), the side etch of each resist was 3.0 μm, and the adhesion was good.

【table】 [Brief explanation of the drawing]

The drawing is an explanatory diagram of how light reflected on the substrate surface goes under the light shielding part during exposure of the photoresist. DESCRIPTION OF SYMBOLS 1... Mask, 2... Mask light-shielding part, 3... Mask light-transmitting part, 4... Incident light, 5... Light that went around under mask light-shielding part, 6... Photoresist, 7... Slope in step structure part, 8... Substrate .

Claims (1)

[Scope of Claims] 1. A cyclized product of a conjugated diene polymer or copolymer, a photocrosslinking agent soluble in an organic solvent, a storage stabilizer, and the general formula Ar-N=N-NH-Ar' (wherein, 1. A photoresist composition containing a compound represented by Ar and Ar′ are the same or different aromatic groups. 2 The compound represented by the above general formula is added at a rate of 0.1 to the cyclized product of the conjugated diene polymer or copolymer.
The photoresist composition according to claim 1, wherein the photoresist composition is added in an amount of up to 10% by weight.