JPH02251960A - Positive type photosensitive composition - Google Patents

Abstract

PURPOSE:To obtain the above compsn. which prevents the halation from a substrate and has good shape stability and dimensional stability and a high sensitivity by compounding the ester of a specific azo compd. and 1,2- naphthoquinone diazide sulfonic acid with a positive type photoresist. CONSTITUTION:The ester of the azo compd. expressed by formula I and the 1,2-naphthoquinone diazide sulfonic acid is compounded with the positive type photoresist. In the formula I, R1 and R2 are respectively an alkyl group of 1 to 3C which may be the same or different from each other: n is 1 to 4 integer. The compsn. which can form the resist pattern having the good shape stability and dimensional stability by preventing the halation from the substrate arising at the time of an exposing processing and has the high sensitivity is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel positive-working photosensitive composition, more specifically,
In particular, it has excellent features such as preventing halation from substrates such as aluminum that occurs during exposure processing, providing resist patterns with good shape and dimensional stability, and high sensitivity. The present invention relates to a positive photosensitive composition suitable for microfabrication used in device manufacturing.

2. Description of the Related Art Conventionally, semiconductor elements such as transistors, ICs, and LSIs have been manufactured by photoetching. This photoetching method involves forming a photoresist layer on a silicon wafer, overlaying a mask with a desired pattern on it, exposing it to light, developing it to form an image, etching the exposed substrate, and then selective diffusion. This is the way to do it. Then, after selective diffusion is performed by repeating such a process several times, an aluminum electrode wiring process is performed to produce a semiconductor electronic component.

In the manufacture of such a semiconductor device, if selective diffusion is performed several times, a level difference of lum or more usually occurs on the surface, and if padding is performed on this, the level difference becomes even larger.

In order to provide aluminum wiring on such a surface, it is necessary to vacuum-deposit aluminum on the surface and then etch it using a photoetching method. However, if a photoresist layer is formed on the vacuum-deposited aluminum and exposed to light, , the halation from the aluminum surface is large, and the actinic rays incident perpendicularly to the substrate surface not only on the flat part of the surface but also on the step part mentioned above cause diffuse reflection on the sloped surface of the step part, resulting in several There was a drawback that the thin line pattern of the μ shoulder could not be accurately reproduced.

Therefore, various methods have been tried to prevent such halation. One of them is
A photoresist containing a light-absorbing dye, such as a specific azo compound having at least one hydroxyl group in the molecule, is known (Japanese Patent Laid-Open No. 142538/1983).

However, although the photoresist to which this light-absorbing dye is added has significantly improved antihalation effect compared to conventional photoresists, it is necessary to keep up with the rapid miniaturization of processing dimensions in the semiconductor industry in recent years. This also poses a problem and cannot be said to be completely satisfactory. Furthermore, on a substrate with a step, the film thickness of the positive photoresist to be applied differs between the step convex part and the recessed part, and the thinner film thickness on the step protrusion is different from the thicker film thickness on the recessed part. Because it is easy to overexpose, even a small amount of halation can cause the resist pattern to become thinner in thinner areas during development, deform the cross-sectional shape of the pattern, and deteriorate the dimensional stability of the resist pattern. Alternatively, if the resist pattern is fine, it has drawbacks such as wire breakage, and not only does it have the problem of not being able to support fine pattern formation.
When a light-absorbing dye is added to a photoresist to prevent halation, the light-absorbing dye absorbs actinic rays during exposure, reducing the sensitivity of the photoresist and reducing the throughput in the manufacturing process of semiconductor devices, making it impractical. do not have.

It is also known that a resist pattern with excellent dimensional stability is obtained by a so-called multilayer method, in which an organic film with antihalation and planarizing effects is formed on a substrate, but this method requires many process steps. It is inevitable that the process will be complicated and the operation will be complicated.

On the other hand, a positive-working photoresist composition comprising a photoactive compound containing an ester of diazooxide and a curcumin dye and a polymer binder has been disclosed (Japanese Patent Laid-Open No. 1983-1993-1).
267941), this positive photoresist composition has extremely poor light transmittance in exposed areas, so the exposure time must be lengthened, and as a result, the cross-sectional shape of the resulting resist pattern has streaks. It has the disadvantage that it tends to become eroded and has a poor profile shape.

Problems to be Solved by the Invention The present invention overcomes the drawbacks of conventional photosensitive compositions as described above, in order to respond to the rapidly progressing miniaturization of processing dimensions in the field of semiconductor device manufacturing. Single layer,
In particular, it is possible to prevent halation from substrates such as aluminum that occurs during exposure processing, and provide a resist pattern with good shape and dimensional stability.Moreover, the sensitivity is high, and the profile shape of the resist pattern is also good. This was made with the aim of providing a positive photosensitive composition having excellent characteristics such as.

Means for Solving the Problems The present inventors have conducted intensive research to develop a positive photosensitive composition having such excellent characteristics. As a result, the present inventors have added a specific azo compound to a conventional positive photoresist. 1. It was found that the above object was achieved by blending an ester with 2-naphthoquinonediazide sulfonic acid,
Based on this knowledge, we have completed the present invention.

That is, the present invention provides (A) positive photoresist with (
B) General formula (in the formula, R1 and R1 are each an alkyl group having 1 to 3 carbon atoms, and they may be the same or different from each other, n is an alkyl group having 1 to 4 carbon atoms, The present invention provides a positive photosensitive composition comprising an azo compound represented by the following integer and an ester of 1,2-naphthoquinonediazide sulfonic acid.

The present invention will be explained in detail below.

In the composition of the present invention, the positive photoresist used as component (A) is not particularly limited and can be arbitrarily selected from commonly used ones. We can list things that are made of matter.

The photosensitive substance includes a quinonediazide group-containing compound,
For example, quinonediazides such as orthobenzoquinonediazide, orthoquinonediazide, and orthoanthraquinonediazide, partially or completely esterified or partially or completely amidated with a sulfonic acid and a compound having a phenolic hydroxyl group or an amino group, Examples of the above-mentioned compounds having a phenolic hydroxyl group or amino group include 2.3.4-trihydroxybenzophenone, 2.2', 4.4'-tetrahydroxybenzophenone, and 2.3.4.4'-tetrahydroxy. Polyhydroxybenzophenone such as benzophenone, or alkyl gallate, aryl gallate, phenol, p-methoxyphenol, dimethylphenol, hydroquinone, bisphenol A1 naphthol, pyrocatechol, pyrogallol, pyrogallol monomethyl ether, pyrogallol-1,3-dimethyl ether, gallic acid. Examples include acid, gallic acid which is esterified or etherified with some hydroxyl groups remaining, aniline, p-aminodiphenylamine, and the like.

In addition, the film-forming substances that are blended into this positive photoresist include, for example, phenol, novolac resin obtained from cresol, xylenol, etc., and aldehydes, acrylic resin, polyvinyl alcohol, copolymer of styrene and acrylic acid, hydroxyl styrene polymer,
Alkali-soluble resins such as polyvinylhydroxybenzoate and polyvinylhydroxybenzal are effective.

Preferred positive photoresists in the composition of the present invention include those using cresol novolak resin as a film-forming substance.

A particularly preferred Talesol novolac resin is one obtained from a mixed cresol of 10 to 45% by weight of m-cresol and 90 to 55% by weight of p-cresol. A more preferable cresol novolac resin is a mixture of the following two types of cresol novolac resins, namely, a mixture of cresols of 60 to 80% by weight of m-cresol and 40 to 20% by weight of p-cresol. A weight average molecular weight of 50 obtained from a cresol novolak resin with an average molecular weight of 5000 or more (in terms of polystyrene) and a mixed cresol of 10 to 40% by weight of m-cresol and 90 to 60% by weight of p-cresol.
00 or less (in terms of polystyrene) and m-cresol 30 to 50 in terms of cresol.
% by weight and p-cresol mixed at a ratio of 70 to 50% by weight. Furthermore, although m-cresol and p-cresol are used as one of these cresol novolak resins, those blended with 0-cresol, xylenol, etc. can also be used if necessary.

By using the resol novolac resin as a film-forming material, a resist pattern with even better dimensional accuracy and dimensional stability can be obtained.

In the positive photoresist of component (A) used in the composition of the present invention, the photosensitive substance is usually blended in an amount of 10 to 40% by weight based on the film forming substance. If this amount is less than 10% by weight, it is difficult to obtain a resist pattern with a desired cross-sectional shape, which is not practical, and if it exceeds 40% by weight, the sensitivity tends to deteriorate significantly, which is not preferable.

In the composition of the present invention, as component (B), an ester of an azo compound represented by the general formula (in which R1, R2 and n have the same meanings as above) and 1,2-naphthoquinonediazide sulfonic acid is used. used.

Such esters include, for example, the azo compound represented by the general formula (I) and 1,2-naphthoquinonediazide-4.
-sulfonic acid or 1,2-naphthoquinonediazide-5-
It can be obtained by esterification reaction with sulfonic acid. Specifically, the azo compound represented by the general formula (I) and 1,2-naphthoquinonediazide-4-sulfonyl chloride or 1,2-naphthoquinonediazide-5-sulfonyl chloride are mixed in a suitable solvent such as N, N- It can be produced by dissolving it in dimethylacetamide or the like and subjecting it to an esterification reaction in the presence of a catalyst such as triethanolamine. Further, as the azo compound represented by the general formula (I), for example, 4-hydroxy-4'-
Dimethylamine azobenzene, 4-hydroxy-4'-
Diethylaminoazobenzene, 2,4-dihydroxy-
4'-dimethylaminoazobenzene, 2,4-dihydroxy-4'-diethylaminoazobenzene, 2,4-dihydroxy-4'-dipropylaminoazobenzene and the like are preferably used.

In the composition of the present invention, the ester of the azo compound represented by the general formula (I) and 1,2-naphthoquinonediazide sulfonic acid used as component (B) is usually obtained from the esterification reaction composition obtained as described above. It can be obtained by refining a substance. In the composition of the present invention, the ester of the component (B) is based on the solid content of the positive photoresist (the total amount of the photosensitive substance and film-forming substance contained in the positive photoresist) of the component (A). hand,
0.25-20% by weight, preferably 0.5-10% by weight
It is desirable to mix in the ratio of . This amount is 0.2
If it is less than 5% by weight, the antihalation effect will not be sufficiently exhibited, and if it exceeds 20% by weight, streaks will tend to occur in the cross-sectional shape of the resist pattern, which is not preferable.

Further, the composition of the present invention only needs to contain an ester of the azo compound represented by the general formula (I) and 1,2-naphthoquinonediazide sulfonic acid, and the esterification reaction composition obtained by the production method described above. can also be used. In this case, it is preferable to use an esterification reaction composition containing 50% by weight or more of ester,
If it is less than 50% by weight, it is not preferable because it is difficult to obtain a resist pattern with a good cross-sectional shape. Note that the amount of the ester in the esterification reaction composition can be easily determined by liquid chromatography.

Furthermore, talcumin, coumarin-based morin dyes, etc. may be added to the composition of the present invention, if necessary, and other additives such as additional resins, plasticizers, stabilizers, or It is also possible to add or contain conventionally used coloring agents to make the pattern more visible.

The composition of the present invention is advantageously used in the form of a solution by dissolving the above-mentioned photosensitive substance, film-forming substance, ester of an azo compound, and optional additive components in required amounts in a suitable solvent. .

Examples of such solvents include acetone, ketones such as methyl ethyl ketone, cyclohexanone, isoamyl ketone, monomethyl ether, monoethyl ether, monopropyl ether of ethylene glycol, propylene glycol, ethylene glycol monoacetate, diethylene glycol or diethylene glycol monoacetate. , polyhydric alcohols and their derivatives such as monoisopropyl ether, monobutyl ether or monophenyl ether; transparent ethers such as dioxane; and esters such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate. can. These may be used alone or in combination of two or more.

Next, to give an example of a preferred method of using the composition of the present invention, first, on a substrate such as a silicone wafer, the above film-forming substance, the photosensitive substance, and the above general formula (I) are coated.
A solution of an ester of an azo compound represented by the formula and 1,2-naphthoquinonediazide sulfonic acid and various dyes and additives added as necessary dissolved in the above solvent is coated with a spinner, dried, and exposed to positive tone. After forming the photosensitive composition (photosensitive layer), it is exposed to light through a required mask using a reduction projection exposure device or the like. Next, this is developed using a developer, for example, an aqueous solution of 2 to 5% by weight of tetramethylammonium hydroxide or choline.
It is possible to obtain an image faithful to the mask pattern in which the portions solubilized by exposure are selectively dissolved and removed.

Effects of the Invention The positive photosensitive composition of the present invention comprises a specific azo metal and 1
．． By adding and using an ester with 2-su7toquinonediazide sulfonic acid, the solubility in the alkaline developer in the area exposed to actinic rays is improved, and conversely, the dissolution in the alkaline developer in the non-exposed area is suppressed. Therefore, a resist pattern with extremely excellent dimensional stability and dimensional accuracy can be obtained. In addition, it is used to prevent halation; compared to various conventional additives, the ester of the specific azo compound and 1,2-naphthoquinonediazide sulfonic acid used in the present invention can be added to photoresists. , since it does not reduce the sensitivity of photoresist, it does not reduce the throughput in the manufacturing process of semiconductor devices, etc.
Extremely practical.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Production example 1 4-hydroxy-4'-dimethylaminoazobenzene 1
0 g and 1.2-su7toquinone diazido 5-sulfonyl chloride 8.19 to N,N-dimethylacetamide 3
50g, and add 8g of triethanolamine to it with N
, dissolved in 32 g of N-dimethylacetamide, was added dropwise over 1 hour while stirring thoroughly. then 35
4-Hydroxy-4 An esterification reaction composition (ester content: 75% by weight) of '-dimethylaminoazobenzene was obtained.

Production Example 2 In Production Example 1, l,2-naphthoquinonediazide-5
- The esterification reaction composition (
An ester content of 25% by weight was obtained.

Production Example 3 In Production Example 1, l,2-naphthoquinonediazide-4
An esterification reaction composition (ester content: 50% by weight) was obtained in the same manner as in Example 1, except that 5.4 g of -sulfonyl chloride was used.

Production Example 4 In Production Example 1, 1.2-naphthoquinonediazide-4
An esterification reaction composition (ester content: 100% by weight) was obtained in the same manner as in Production Example 1, except that 10.89% of -sulfonyl chloride was used.

Example 1 0FPR-800 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.: solid content 27% by weight), which is a positive photoresist containing a cresol novolac resin and at least an 0-naphthoquinonediazide compound as a photosensitive substance, was used. Then, 3% by weight of the esterification reaction composition obtained in Production Example 1 was blended and dissolved in this solid content, and then filtered through a membrane filter.
A coating solution was prepared by filtration. Apply this coating solution to
Using a spinner, deposit aluminum on a 4-inch silicon wafer with an opm step.
After coating to a film thickness of 2.0 μm, it was placed on a hot plate and prebaked at 110° C. for 90 seconds to form a photosensitive layer.

Next, a reduction projection exposure device 1505 is applied to the photosensitive layer on the substrate.
G 3 Affi wafer stepper (Nippon Kogaku Kogyo (
Afterwards, the resist pattern was formed on the substrate by developing with a 2.38 wt% tetramethylammonium hydroxide aqueous solution at 23°C for 30 seconds. was formed. When this pattern was observed using an electron microscope, it was found that a 0.8 μm pattern faithful to the mask was formed even on the step convex part where the coating film thickness was relatively thin, and the cross-sectional shape was almost vertical and extremely sharp. Met.

In addition, as for sensitivity, the minimum exposure time to obtain a 1.0 μm line-and-space pattern was measured and found to be 160 m5.

Example 2 m-
Cresol and p-cresol in a weight ratio of 60:4
Formalin was added to this, and condensation was carried out in a conventional manner using an oxalic acid catalyst to obtain a weight average molecular weight of 280.
After obtaining 00 cresol novolac resin (I), m-cresol and p-cresol were similarly added at a weight ratio of 40.
: Mixed and condensed at a ratio of 60%, weight average molecular weight 2
000 Talesol novolac resin (II) was obtained.

30 parts by weight of resin (I), 70 parts by weight of resin (II), 2.
3. 1 mol of 4-1-lyhydroxybenzophenone and 1.6 mol of naphthoquinone-1,2-diazide sulfonic acid chloride
After dissolving 3% by weight of the esterification reaction composition obtained in Production Example 1 in 390 parts by weight of ethylene glycol monoethyl ether acetate, 3% by weight of the esterification reaction composition obtained in Production Example 1 was dissolved in 390 parts by weight of ethylene glycol monoethyl ether acetate. A coating solution was prepared by filtration using a 2 μm membrane filter. Using this coating liquid, a resist pattern was formed in the same manner as in Example 1.

When this resist pattern was observed using an electron microscope, it was found to be as excellent as in Example 1.

Further, when the minimum exposure time was measured in the same manner as in Example 1, it was 180 m5.

Example 3 Esterification reaction composition used in Example 1 (Production Example 1)
Instead, a mixture of 2% by weight of the esterification reaction composition obtained in Production Example 3 and 1% by weight of l-ethoxy-4-(4'-N,N-diethylaminophenylazo)benzene was used. A resist pattern was formed in the same manner as in Example 1. The observation results of this resist pattern were the same as in Example 1.

Further, when the minimum exposure time was measured in the same manner as in Example 1, it was 190 m5.

Example 4 Esterification reaction composition used in Example 1 (Production Example 1)
A resist pattern was formed in the same manner as in Example 1 except that 3% by weight of the esterification reaction composition obtained in Production Example 4 was used instead of Although a sharp pattern was obtained as in Example 1, some halation from the lateral direction was observed in the resist pattern at the step portion.

Further, when the minimum exposure time was measured in the same manner as in Example 1, it was 150 m5.

Comparative Example 1 Instead of the esterification reaction composition used in Example 1,
A resist pattern was formed in the same manner as in Example 1 except that 4-hydroxy-4'-dimethylaminoazobenzene was used, but the resist pattern had a rounded top and poor sharpness.

Further, when the minimum exposure time was measured in the same manner as in Example 1, it was 180 m5.

Example 5 m-cresol and p-cresol in a weight ratio of 4026
100 parts by weight of Talesol novolac resin obtained by adding formalin to this and condensing it in a conventional manner using an oxalic acid catalyst, and 2 parts of naphthoquinone-1,2-diazide-5-sulfonic acid. .3. To a solution obtained by dissolving 1 part of 4-trihydroxybenzophenone ester 301J in 390 parts by weight of ethylene glycol monoethyl ether acetate, add 3 parts of the esterification reaction composition obtained in Production Example 1 to the solid content. After dissolving % by weight, 0
．． A coating solution was prepared by filtration using a 2 μm membrane filter. Using this coating liquid, a resist pattern was formed in the same manner as in the example.

When this resist pattern was observed with an electron microscope, it was found that the cross-sectional shape was extremely vertical and sharp, as in Example 1.

Further, when the minimum exposure time was measured in the same manner as in Example 1, it was 160 m5.

Example 6 Esterification reaction composition used in Example 5 (Production Example 1)
A resist pattern was formed in the same manner as in Example 5, except that 1.5% by weight of the esterification reaction composition obtained in Production Example 3 was used in place of the solid content, and a resist pattern was formed in the same manner as in Example 1. The resist pattern had an extremely sharp cross-sectional shape.

Further, when the minimum exposure time was measured in the same manner as in Example 1, it was 170 m5.

Comparative Example 2 Instead of the esterification reaction composition used in Example 1,
4-ethoxy-4'-diethylaminoazobenzene
When a resist pattern was formed in the same manner as in Example 1 except that % by weight was used, the resist pattern had a rounded top and poor sharpness.

Further, when the minimum exposure time was measured in the same manner as in Example 1, it was 450 m5.

Example 7 Esterification reaction composition used in Example 5 (Production Example 1)
A resist pattern was formed in the same manner as in Example 5, except that 1.5% by weight of the esterification reaction composition obtained in Production Example 2 and 1.5% by weight of curcumin were used in place of the solid content. However, as in Example 1, the resist pattern had an extremely sharp cross-sectional shape.

Further, when the minimum exposure time was measured in the same manner as in Example 1, it was 160 n+s.

Example 8 Esterification reaction composition used in Example 1 (Production Example 1)
2,4-dihydroxy-4'-diethylaminobenzene 109 and 1,2-naphthoquinonediazide-4-sulfonyl chloride 18. Except for using h.
2,4-dihydroxy- obtained in the same manner as in Production Example 1
Except for using an esterification reaction composition of 4'-diethylaminoazobenzene (ester content: 80% by weight).
When a resist pattern was formed in the same manner as in Example 1, the resist pattern had an extremely sharp cross-sectional shape as in Example 1.

Further, when the minimum exposure time was measured in the same manner as in Example 1, it was 150 m5.

Claims (1)

[Claims] 1 (A) positive photoresist, (B) general formula▲mathematical formula,
There are chemical formulas, tables, etc.▼ (R^1 and R^2 in the formula are each an alkyl group having 1 to 3 carbon atoms, and they may be the same or different from each other, 1. A positive photosensitive composition comprising an azo compound represented by the formula (n is an integer of 1 to 4) and an ester of 1,2-naphthoquinonediazide sulfonic acid. 2. The positive photosensitive composition according to claim 1, wherein the amount of component (B) is 0.25 to 20% by weight based on the solid content of the positive photoresist as component (A).