JPH0323453A - Positive type photosensitive composition - Google Patents

Abstract

PURPOSE:To form a resist pattern suitable for micro fabrication and superior in diemnsional stability and a profile form by incorporating a specified azomethine compound in a positive type photoresist. CONSTITUTION:The positive type photoresist contains the azomethine compound represented by formula I in which each of R<1> - R<4> is H, halogen, OH, nitro, cyano, 1 - 3 C alkyl or the like, and each may be same or different. The positive type photoresist is not especially limited, and the ones comprising a photosensitive material and a film forming material can be used, thus permitting the dimensional stability and the profile form of the resist pattern to be enhanced to any exposure to light.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to positive-working photosensitive compositions. More specifically, the present invention relates to a positive photosensitive composition capable of forming a resist pattern with excellent dimensional stability and profile shape, which is particularly suitable for microfabrication of semiconductor devices and the like.

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

In the manufacture of such a semiconductor device, if selective diffusion is performed several times, a step of 1 μm or more is usually produced on the surface, and if bansivation is applied to this step, the step 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. In this case, the halation from the aluminum surface is large, and in particular, at the stepped portion, the actinic rays incident perpendicularly to the substrate surface will be diffusely reflected on the sloped surface of the stepped portion, resulting in thin blades of several μm. Accurate line pattern
There was a problem that this could not be reproduced.

Therefore, various methods have been tried so far to prevent this halation. As one of these, a technology has been developed to add a light-absorbing dye to photoresist, and a method using a specific azo compound having at least one hydroxyl group in the molecule as a light-absorbing dye is known (Japanese Patent Application Laid-Open No. 59-1999).
- Publication No. 142538).

However, although the photoresist to which this light-absorbing dye has been added has significantly improved anti-nozzle effect compared to conventional photoresists, it is still only slightly effective in responding to the rapid miniaturization of processing dimensions in the semiconductor industry in recent years. Halation has also become a problem, and the current situation is that it is no longer fully satisfactory. Furthermore, on a substrate with steps, the thickness of the positive photoresist applied is
There is a difference between the stepped convex part and the concave part, and the thinner part on the stepped part is more likely to be overexposed than the thicker part on the concave part. The resist pattern in the thin part of the
Resist butterflies, such as poor cross-sectional shape of the pattern;-
This method not only impairs the dimensional stability of the resist pattern but also has drawbacks such as wire breakage in fine resist patterns, and there is also the problem that it cannot be applied to fine pattern shapes.

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. The object of this invention is to provide a positive photosensitive composition that can form a resist pattern with extremely excellent dimensional stability and profile shape.

Means for Solving the Problems As a result of extensive research by the present inventors in order to develop a positive photosensitive composition capable of forming a resist pattern with extremely excellent dimensional stability and profile shape, It was discovered that the objective could be achieved by blending a specific azomethine compound into a conventional positive photoresist, and based on this knowledge, the present invention was completed.

That is, the present invention provides (A) positive photoresist with (
B) General formula (Rlj92, R3 and R4 in the formula are each a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, or an alkyl group) is a dialkylamino group having 1 to 3 carbon atoms, which may be the same or different from each other). This is what we provide.

The present invention will be explained in detail below.

In the composition of the present invention, the positive photoresist used as (A) is not particularly limited and can be arbitrarily selected from commonly used ones, but it is preferable to use a photosensitive material and a photoresist. Some examples include film forms and certain substances.

The photosensitive substance includes a quinonediazide group-containing compound,
Examples include partial or complete esterification or partial or complete amidation of sulfonic acid of quinone diazides such as orthobenzoquinone diazide, honoretna 7-toquinone diazide, and honoretanthraquinone diazide with a compound having a 7-enolic hydroxyl group or an amino group. Examples of the compound having a phenolic hydroxyl group or an amino group include 2,3,4-1-lihydroxybenzophenone, 2,2',4,4'-tetrahydroquine penzophenone, 2,3 , 4,4'-tetrahydrooxybenzobenzo7enone, polyhydroxybenzophenones such as alkyl gallate, aryl gallate, phenol, p-methoxyphenol, dimethyl7enol, hydroquinone, bisphenol A1 naphthone, hyrocatechol, hyrogallonol, biro Gallol monomethyl ether, bilogallol-1,3-dimethyl ether, gallic acid, gallic acid esterified or etherified with some hydroxyl groups left, aniline, p-aminodi7enylamine, and the like.

Film-forming substances to be added to this positive photoresist include, for example, nopolac resins obtained from phenol, cresol, quinrenol, etc. and aldehydes, acrylic resins, copolymers of styrene and acrylic acid,
Alkali-soluble resins such as hydroxystyrene polymers, polyvinylhydroxybenzoate, and polyvinylhydroxybenzal are effective.

In the composition of the present invention, a particularly preferred positive photoresist is one using Talesol nopolac resin as a film-forming substance, particularly 10 to 45% by weight of m-cresol.
Preferably, those obtained from a mixed cresol of 90 to 55% by weight of p-cresol and p-cresol are used. More preferably, 60 to 80% by weight of m-cresol and 40 to 20% by weight of p-cresol.
Weight average molecular weight obtained from mixed cresols of 5% by weight
Talesol with a weight average molecular weight of 5,000 or less (in terms of polystyrene) obtained from a mixed cresol of 000 or more (in terms of polystyrene) and a mixed cresol of ~40% by weight of m-cresol lO and 90 to 60% by weight of p-cresol. Novolank resin is 30 to 46.5% by weight of m-cresol and 70% by weight of p-cresol in terms of cresol.
It is obtained from mixed cresols mixed in a proportion such that it becomes ~53.5% by weight.

In the positive photoresist used in the present invention, the above-mentioned photosensitive substance is usually 20 to 4
It is blended in a range of 0% by weight. If this amount exceeds 40% by weight, the sensitivity will be significantly inferior, and if this amount is less than 20% by weight, it will be difficult to obtain a preferable pattern cross-sectional shape.

In the composition of the present invention, the general formula (R1,
It is necessary to blend an azomethine compound represented by (R2, R3 and R4 have the same meanings as above).

Specific examples of the azomethine compound represented by the general formula (1) include 3-hydroxy-4'-diethylaminobenzylideneaniline, 2-hydroxy-4'-diethynoleaminobenzylideneaniline, and 2,4-dihydroquine-4'. -diethylaminobenzylideneaniline, 5-chloro-2-hydroquine-4'-diethylaminobenzylideneaniline, 4-hydroxy-3-nitro-4'-diethylaminobenzylideneaniline, 4-hydroxy-2-methyl-4'-diethylaminobenzylideneaniline, 3 -Hydroxy-4-methoxy-4'-jethylaminobenzylideneaniline, 4-hydroxy-4'-dimethynoleaminobenzylideneaniline, 4-nitro-2
',4'-dimethoxybenzylideneaniline, 4-hydrooxy-2',4'-dimethoxybenzylideneaniline, 4-ethoxy-3-nitropenzylideneaniline, 4-methoxy-4'-diethylaminobearzylideneaniline, 4- Examples include cyano-4'-diethylaminobenzylideneaniline, 4-hydroxy-4'-diethylaminobenzylideneaniline, and among these, 4-hydroxy-4'-diethylaminobenzylideneaniline and 4-hydroxy-2', 4'-Dimethquine benzylideneaniline is preferred.

In the composition of the present invention, these azomethine compounds may be used alone or in combination of two or more. The blending amount thereof is usually selected in the range of 6.5 to 20% by weight, preferably 1 to 10% by weight, based on the solid content of the positive photoresist of component (A). If this amount is less than 0.5% by weight, the antihalation effect will be low and the object of the present invention will not be fully achieved.
If it exceeds % by weight, the cross-sectional shape of the resist pattern tends to deteriorate, which is not preferable.

In addition, the positive type photosensitive composition of the present invention may include, if necessary,
Other compatible dyes, such as coumarin dyes, azo dyes, etc., may also be added, as well as other additives, such as additional resins, plasticizers, stabilizers or the pattern obtained on development. It is also possible to add and contain commonly used coloring agents to make it even more visible.

The positive photosensitive composition of the present invention requires the above-mentioned photosensitive substance, film-forming substance, azomethine compound represented by general formula (1), and additives used as necessary, in a suitable solvent. It is advantageous to dissolve the amount and use it in the form of a solution.

Examples of such solvents include ketones such as acetone, methylethynoleketone, cyclohexane, isoaminoreketone; monomethyl ether of ethylene glycol, ethylene glycol monoacetate, diethylene glycol or diethylene glycol heptanoacetate;
Polyhydric alcohol M such as monoethyl ether, monobrobyl ether, monobutyl ether or monophenyl ether and its derivatives: cyclic ethers such as dioxane: methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, etc. Esters: and N,N-dimethylformamide, N,N-dimethylacetamide, N
Mention may be made of aprotic polar solvents such as -methyl-2-pyrrolidone. These may be used alone or in combination of two or more.

Next, to give an example of a preferred method of using the composite of the present invention, first, the above-mentioned film-forming substance, photosensitive substance, azomethine compound, and various other substances added as necessary are placed on a substrate such as a silicon wafer. A solution of dyes and additives dissolved in a suitable solvent is applied with a spinner, dried to form a photosensitive layer, and then 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 ff% tetramethylammonium hydroxide or choline, so that the portions made solubilized by exposure are selectively dissolved and removed to faithfully reproduce the mask pattern. You can get a good image.

The reduction projection exposure apparatus used when forming a resist pattern using the positive photosensitive composition of the present invention may use either an i-line or a g-line as its light source. By using a reduction projection exposure device that uses i-rays as a light source, the present invention can obtain a resist pattern with particularly excellent dimensional stability and an excellent cross-sectional shape that is faithful to the mask pattern. It has the characteristic that a resist pattern can be obtained.

Effects of the Invention By incorporating a specific azomethine compound into a conventional positive photoresist, the positive-working photosensitive atfR product of the present invention significantly improves the dimensional stability and profile shape of the resist pattern with respect to the exposure amount. Since the azomethine compound acts as a light absorbing substance, the antihalation effect can be improved.

However, the present invention is not limited to these examples in any way.

Example 1 OFPR-800 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd., solid content 27% by weight), which is a positive photoresist containing a phenol nopolac resin and at least an 0-naphthoquinone diazide compound as a photosensitive substance, was used. A coating solution was prepared by blending 4-hydroxy-4'-diethylaminobenzylidene aniline 3f [% by weight] with respect to this solid content, and then filtering through a Menpuran filter. Using a spinner, this coating solution was applied onto a 4-inch silicon wafer with a step of 1.0 μm on which aluminum was deposited. After coating to give Opm, the film was placed on a real plate and prebaked at 110°C for 90 seconds to form a film.

Next, the film on the substrate is coated with the iHa reduction projection exposure system NSR.
After exposing the substrate to light through a test chart mask using an I010i3 type wafer stepper (manufactured by Nikon Corporation), the substrate was developed with a 2.38% by weight tetramethylammonium hydroxide aqueous solution at 23°C for 30 seconds. The resist pattern was marked on top. When this pattern was observed using an electron microscope, it was found that even on stepped convex parts where the coating film thickness is relatively thin, a 0.8 μm coating faithful to the mask was obtained.
A pattern of m was formed, and its cross-sectional shape was almost vertical and extremely sharp.

Example 2 M-
Cresol and p-cresol were mixed at a weight ratio of 60:40, formalin was added to this, and the mixture was condensed using a sulfuric acid catalyst in a conventional manner to obtain a weight average molecular weight of 28,000.
After obtaining the cresol novolak resin (T), m-cresol and p-cresol were similarly added in a weight ratio of 40+6.
They were mixed and condensed at a ratio of 0.0 to obtain a Talesol novolac resin (If) having a weight average molecular weight of 2000.

30 parts by weight of resin (1), 70 parts by weight of resin (II), 2,
3.4-1 mol of trihydroxybenzophenone and naphthoquinone-1,2-diazide sulfonic acid chloride 1.
After dissolving 30 parts by weight of the reaction product with 6 mol and 3% by weight of 4-hydroxy-4'-diethylaminopenzylideneaniline based on the solid content in 390 parts by weight of ethyl lactate, A coating solution was prepared by filtration using a Menpuran filter. Using this coating liquid,
A resist pattern was formed in the same manner as in Example 1. When this resist pattern was observed with an electronic MA mirror,
It was as excellent as Example 1.

Example 3 In Example 2, 4-hydroxy-2'. 4'-dimethoxybenzylideneaniline 3
A resist pattern was formed in the same manner as in Example 2 except that % by weight was used. When this resist pattern was observed with an electron microscope, it was found to be as excellent as in Example 1.

Example 4 A resist pattern was formed in the same manner as in Example 1 except that 8% by weight of 4-hydroxy-4'-diethylaminobenzylideneaniline was added. When this resist pattern was observed with an electron microscope, it was found to be as excellent as in Example 1.

Example 5 2% by weight of 4-hydroxy-4'-diethylaminobenzylideneaniline and 1-ethoxy-4-(4'-N,N-diethylaminophenyl) in place of 3t% of 4-hydroxy-4'-diethylaminobenzylideneaniline A resist pattern was formed in the same manner as in Example 1, except that a mixture of 1% by weight of azo)benzene was used. The results of the visual inspection of this resist pattern were the same as in Example 1.

Embodiment 6 In Embodiment 1, the reduction projection exposure apparatus was replaced with a reduction projection exposure apparatus for g-rays NSR 1505G3A type wafer/1-stepper=
A resist pattern was formed in the same manner as in Example 1, except that the resist pattern was replaced with (manufactured by Nikon Corporation). When this resist pattern was observed with an electron microscope, its cross-sectional shape was vertical and extremely sharp, and it was found to be a resist pattern that was extremely faithful to the mask pattern and had excellent dimensional stability.

Comparative Example A resist pattern was formed in the same manner as in Example 1, except that 25% by weight of 4-hydroxy-4'-diethylaminobenzylideneaniline was blended. When this resist pattern was observed with an electron microscope, the lower part of the resist pattern was widened and was not practical.

Claims (1)

[Claims] 1 (A) positive photoresist, (B) general formula▲mathematical formula,
There are chemical formulas, tables, etc. ▼ (In the formula, R^1, R^2, R^3 and R^4 are hydrogen atoms, halogen atoms, hydroxyl groups, nitro groups, cyano groups, and alkyl having 1 to 3 carbon atoms, respectively. group, an alkoxy group having 1 to 3 carbon atoms, or a dialkylamino group having 1 to 3 carbon atoms in the alkyl group, which may be the same or different from each other) A positive photosensitive composition comprising: 2. The positive photosensitive composition according to claim 1, wherein the amount of the azomethine compound is 0.5 to 20% by weight based on the solid content of the positive photoresist.