JPH02287545A - Positive type photosensitive composition - Google Patents

Abstract

PURPOSE:To effectively prevent halation during exposure and to improve the dimensional stability and dimensional accuracy of a resist pattern by adding a specified ester to a compsn. CONSTITUTION:A photosensitive compsn. contg. the ester of a flavone compd. represented by the formula with 1,2-naphthoquinonediazidosulfonic acid is used as a positive type photoresist. In the formula, one or more among R<1>-R<9> are OH and the remainders are H. The ester may be the ester of 2,3,4,4'- tetrahydroxybenzophenone with 1,2-naththoquinonediazido-5-sulfonic acid. Cresol- novolak resin may be used as the base of the compsn. and the compsn. may be dissolved in ethyl lactate and applied with a spinner.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to positive-working photosensitive compositions, more specifically, to prevent halation from substrates such as aluminum that occur during exposure, and to improve shape stability and dimensional stability. The present invention relates to a positive photosensitive composition that can provide a good resist pattern and is suitably used, for example, in microfabrication in the manufacture of semiconductor devices.

2. Description of the Related Art Conventionally, semiconductor devices 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 manufacturing such a semiconductor device, if selective diffusion is performed several times, a step of 1 pm or more is usually generated on the surface, and if passivation is applied to this step, the step becomes even thicker.

In order to provide aluminum wiring on such a surface, it is necessary to vacuum-deposit aluminum on the surface and pattern and etch it using a photoetching method. However, a photoresist layer is formed on the aluminum vacuum-deposited on the surface and then exposed When this is done, the halation from the aluminum surface is large, and the active rays incident perpendicularly to the substrate surface are diffusely reflected not only on the flat part of the surface but also on the step part mentioned above. This has the disadvantage that it is not possible to accurately reproduce thin line patterns of several micrometers.

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 a significantly improved anti-nolation effect compared to conventional photoresists, it is only slightly effective in responding to the rapid miniaturization of processing dimensions in the semiconductor industry in recent years. Halation also becomes a problem, and it cannot necessarily be said that it is completely satisfactory. Furthermore, on a substrate with steps,
The thickness of the positive photoresist applied differs between the stepped convex portion and the concave portion, and the thinner film on the stepped convex portion is more likely to be overexposed than the thicker layer on the concave portion. 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, deteriorate the dimensional stability of the resist pattern, or cause problems when the resist pattern is fine. Not only does it have drawbacks such as wire breakage and cannot support fine pattern formation, but when a light-absorbing dye is added to the photoresist to prevent halation, the light-absorbing dye is removed during exposure. absorbs actinic rays and reduces the sensitivity of the photoresist, causing a reduction in throughput in the manufacturing process of semiconductor devices, etc., making it impractical.

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 involves a number of steps, making operations unavoidably complicated.

Furthermore, a positive photoresist composition comprising a photoactive compound containing an ester of diazooxide and a curcumin dye and a polymeric binder has been disclosed (JP-A-63
-267941), this positive photoresist has extremely poor light transmittance in the exposed area.
The exposure time has to be increased, and as a result, the cross-sectional shape of the resulting resist pattern is likely to be lined, resulting in a defective profile shape.

Therefore, it has been strongly desired to develop a highly sensitive positive-working photosensitive composition that has an antihalation effect, has excellent dimensional stability even in a single layer, and provides a pattern with a good 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. Provides a highly sensitive positive-working photosensitive composition that can effectively prevent halation from a substrate such as aluminum that occurs during exposure processing and form a resist pattern with excellent shape stability, dimensional stability, and profile shape. It was done for the purpose of

Means for Solving the Problems The present inventors have conducted extensive research to develop a positive photosensitive composition suitable for forming fine patterns.As a result, the present inventors have added a conventional positive photoresist to a conventional positive photoresist as an antihalation agent.
It was discovered that the objective could be achieved by blending a specific flavone-based compound with an ester of 1,2-naphthoquinonediazide sulfonate, and based on this knowledge, the present invention was completed.

That is, the present invention uses 1,2-naphthoquinone diazide, a flavone compound represented by the general formula (in which at least one of R1 to R9 is a hydroxyl group and the rest are hydrogen atoms), to a positive photoresist. The present invention provides a positive photosensitive composition containing an ester with sulfonic acid.

The present invention will be explained in detail below.

There are no particular restrictions on the photoresist used as the positive resist in the composition of the present invention, and any commonly used photoresist can be selected, but preferably one consisting of a photosensitive substance and a film-forming substance is used. can be mentioned.

The photosensitive substance includes a quinonediazide group-containing compound,
For example, quinone diazides such as orthobenzoquinonediazide, orthonaphthoquinonediazide, orthoanthraquinonediazide, which are 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, may be mentioned. Examples of compounds having a phenolic hydroxyl group or amino group include 2.3.4-trihydroxybenzophenone, 2.2', 4.4'-tetrahydroxybenzophenone, and 2,3,4.4'-tetrahydroxybenzophenone. polyhydroxybenzophenone, such as
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, gallic acid esterified or etherified with some hydroxyl groups left, aniline, p-aminodiphenyleamine, etc. Can be mentioned.

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 polyvinylhydroxybenzyl are effective.

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

A particularly preferred Talesol novolac resin is one obtained from a cresol mixture of 10 to 45% by weight of m-cresol and 90 to 5511% by weight of p-cresol. A more preferred Talesol novolac resin is a mixture of the following two types of Talesol novolak resins, namely m-cresol 60-80
A Talesol novolak resin with a weight average molecular weight of 5000 or more (in terms of polystyrene) obtained from a mixed cresol of 11% by weight and 40 to 20% by weight of p-cresol, and m-
Cresol 10-40% by weight and p-cresol 90-6
Talesol novolak resin with a weight average molecular weight of 5000 or less (in terms of polystyrene) obtained from mixed cresol with 0% by weight of m-cresol 30% in terms of cresol.
45% by weight of p-cresol and 70 to 55% by weight of p-cresol. In addition, in the production of these Talesol novolak resins, m
-Cresol and p-cresol are used, but if necessary, compounds containing 0-cresol, xylenol, etc. can also be used.

By using such Talesol novolac resin as a film-forming substance, a resist pattern with better dimensional accuracy and dimensional stability can be obtained.

In the positive photoresist used in the composition of the present invention, the photosensitive substance is usually 3 times larger than the film forming substance.
It is blended in a proportion of ~30% by weight.

If this amount is less than 3% by weight, it is difficult to obtain a resist pattern with a desired cross-sectional shape, which is not practical, and if it exceeds 30% by weight, the sensitivity tends to deteriorate significantly, which is not preferable.

In the composition of the present invention, the positive photoresist includes:
7 represented by general formula (I) as an antihalation agent
It is necessary to blend an ester of a Labone compound and 1,2-7toquinonediazide sulfonic acid. The 7-rabone compound is not particularly limited as long as it is represented by the above-mentioned formula (1), but includes, for example, chrysin, primethin, abigenin, pyriterein, luteolin, sufterrarein, galandin, fuisetin, kaempferol, Examples include daticetin, robinetin, quercetin, morin, herbacetin, gosypetin, myricetin, quercetagetin, hibiscetin, and the like.

Flavone compounds used in the composition of the present invention and 1.2-
For example, an ester with naphthoquinonediazide sulfonic acid is an example of an ester with a flavone compound represented by the above-mentioned formula (I).
．． It can be obtained as an esterification reaction product with 2-naphthoquinonediazide-4-sulfonyl chloride or 1,2-naphthoquinonediazide-5-sulfonyl chloride. Specifically, a 7-rabone compound represented by formula CI) and 1,2-7toquinonediazide-4-sulfonyl chloride or 1,2-naphthoquinonediazide-5-
It can be produced by dissolving sulfonyl chloride in a suitable solvent such as N,N-dimethylacetamide and subjecting it to an esterification reaction in the presence of a catalyst such as triethanolamine.

The ester of the flavone compound represented by formula (I) and 1,2-naphthoquinonediazide sulfonic acid used in the composition of the present invention is usually an average ester as an esterification reaction product obtained by the production method. Those having a degree of oxidation of 60% or more, preferably 70% or more are used. If the average degree of esterification is less than 60%, it is not preferable because it is difficult to obtain a resist pattern with a good cross-sectional shape. Note that the average degree of esterification of the esterification reaction product can be easily determined by analysis using liquid chromatography.

In the composition of the present invention, the ester of the 7-rabone compound represented by formula (I) and 1,2-naphthoquinonediazide sulfonic acid is the solid content of the positive photoresist (the photosensitive material contained in the positive photoresist). 0.5 to 20% by weight based on the total amount of substance and film-forming substance),
Preferably, it is blended in a proportion of 1-15% by weight. If the amount is less than 0.5% by weight, the antihalation effect will not be sufficiently exhibited, and if it exceeds 20% by weight, the cross-sectional shape of the resist pattern will tend to be poor, which is not preferable.

The positive photosensitive composition of the present invention may optionally contain other compatible dyes such as curcumin, coumarin dyes,
In addition, other additives such as azo dyes may be added, such as additional resins, plasticizers, stabilizers or colorants to make the resulting pattern more visible upon development. It is also possible to add and contain other substances.

The positive photosensitive composition of the present invention can be prepared by dissolving the photosensitive substance, film-forming substance, esterified product of flavone compound, and additive components used as necessary in required amounts in a suitable solvent. Advantageously, it is used in the form of

Examples of such solvents include ketones such as acetoy, methyl ethyl ketone, cyclohexanone, isoamyl ketone; ethylene glyfur, propylene glycol,
Polyhydric alcohols and derivatives thereof such as monomethyl ether, monoethyl ether, monopropyl ether, monoisopropyl ether, monobutyl ether or monophenyl ether of ethylene glycol monoacetate, diethylene glycol or diethylene glycol heptanoacetate; cyclic ethers such as dioxane and esters such as methyl acetate, ethyl acetate, butyl acetate, and ethyl lactate. 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, for example, on a substrate such as a silicon wafer,
The above-mentioned film-forming substance, photosensitive substance, 1,2-7-toquinonediazide sulfonic acid ester of the flavone compound represented by formula (I), and various dyes and additives added as necessary are added to the above-mentioned solvent. A solution dissolved in is applied with a spinner and dried to form a photosensitive layer, which is then exposed to light through a required mask using a reduction projection exposure device or the like.

Next, this is developed with a developer, for example, an aqueous solution of 2 to 5% by weight of tetramethylammonium hydroxide or choline, to create an image faithful to the mask pattern in which the portions solubilized by exposure are selectively dissolved and removed. can be obtained.

Effects of the Invention The positive-working photosensitive composition of the present invention uses 1,2-naphthoquinonediazide sulfonic acid ester of a specific 7-rapone compound, so that the solubility in an alkaline developer in the area exposed to actinic rays is improved. On the contrary, it is possible to suppress the solubility in the alkaline developer in the non-exposed areas, so it is possible to obtain a resist pattern with extremely excellent dimensional stability and dimensional accuracy. In addition, compared to various conventional additives used to prevent halation, the specific flavone-based compound used in the present invention, 1,2-naphthoquinonediazide sulfonic acid ester, can be used in photoresists even when added to it. Since it does not reduce the sensitivity of the semiconductor device, it does not reduce the throughput in the manufacturing process of semiconductor devices, and is extremely practical.

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

Production Example 1 Morin 10g and 1,2-naphthoquinonediazide-5-
44.29 g of sulfonyl chloride was dissolved in 240 g of dioxane, and a solution of 44.7 g of triethanolamine dissolved in 134 g of dioxane was added dropwise to the solution over 1 hour while thoroughly stirring. Then ion exchange water 1000
9 was added to precipitate the reaction product, the resulting precipitate was thoroughly washed with ion-exchanged water, water was removed, and then dried to obtain an esterification reaction product of morin. As a result of analyzing this esterification reaction product by liquid chromatography, the average degree of esterification was 75%.

Production Example 2 Morin esterification reaction product (average degree of esterification 55 %) was obtained.

Production Example 3 A quercetin esterification reaction product (average degree of esterification 75%) was obtained in exactly the same manner as Production Example 1 except that morin was replaced with quercetin.

Production Example 4 Morin was replaced with quercetin, and the amount of 1,2-naphthoquinonediazide-5-sulfonyl chloride used was 26.5%.
The esterification reaction product of quercetin (average degree of esterification 55%) was produced in exactly the same manner as in Production Example 1 except that 9 was changed.
I got it.

Example! The weight ratio of m-cresol and p-cresol is 40:
100 parts by weight of Talesol novolac resin obtained by mixing 100 parts by weight of Talesol novolac resin and 2.3 parts of 1,2-naphthoquinonediazide-5-sulfonic acid by mixing in a ratio of 60 parts by weight, adding formalin to this, and condensing it by a conventional method using an oxalic acid catalyst. .4.1 part by weight of 9 parts of 4'-tetrahydroxybenzophenone ester and 9 parts by weight of the esterification reaction product obtained in Production Example 1 were mixed with 3 parts by weight of ethyl lactate.
The solution obtained by dissolving 90 parts by weight was filtered using a membrane filter with a shoulder size of 0.2μ to obtain a coating solution.

This coating solution was spin-coated onto a 4-inch silicon wafer and dried to form a resist layer with a thickness of 1.28 μm.
G4D (manufactured by Kon) was exposed to 100°
C for 90 seconds, and immersed in a 2.38% by weight tetramethylammonium hydroxide aqueous solution for 65 seconds to obtain a resist pattern. Observation of the obtained resist pattern using an electron microscope revealed that a 0.5 μm resist pattern was obtained which was faithful to the mask and had a cross-sectional shape cut perpendicularly from the silicon wafer surface as shown in FIG.

Examples 2 to 8, Comparative Examples 1 to 4 The components of the cresol novolak resin, the type and amount of the photosensitive substance, and the type and amount of the 1,2-naphthoquinonediazide sulfonic acid ester of the flavone compound are as shown in the table. The cross-sectional shape of the obtained resist pattern was evaluated in the same manner as in Example 1 except for the following changes. The results are shown in the table.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are cross-sectional diagrams of resist patterns obtained after development processing in Examples and Comparative Examples.

Claims (1)

[Claims] 1. A positive photoresist has a general formula ▲a mathematical formula, a chemical formula, a table, etc.▼ (At least one of R^1 to R^9 in the formula is a hydroxyl group, and the rest are hydrogen atoms. A positive photosensitive composition comprising a flavone compound represented by the following formula and an ester of 1,2-naphthoquinonediazide sulfonic acid.