JP2624541B2 - New positive photosensitive composition - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a novel positive photosensitive composition, and more particularly, to a method for preventing halation from a substrate such as aluminum which is generated particularly during an exposure process, and improving shape stability and the like. The present invention relates to a positive photosensitive composition which can provide a resist pattern having good dimensional stability, has high sensitivity, and is suitable for fine processing, for example, for manufacturing semiconductor devices.

2. Description of the Related Art In recent years, semiconductor devices such as transistors, ICs, and LSIs have
It is manufactured by the photo etching method. In this photo-etching method, a photoresist layer is formed on a silicon wafer, a mask having a desired pattern is overlaid thereon, exposed and developed, an image is formed by developing, and then the exposed substrate is etched, and then selected. This is a method of performing diffusion.
Usually, after such a process is repeated several times to perform selective diffusion, 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, the surface usually has a step of 1 μm or more,
If passivation is applied to this, the step will be further increased.

In order to provide aluminum wiring on a surface having such a step, it is necessary to vacuum-deposit aluminum on the surface and etch it by a photoetching method.However, a photoresist layer is formed on the vacuum-deposited aluminum on the surface. In the case of exposure, the halation from the aluminum surface is large, and in particular, in the above-mentioned step portion, the active light beam which is perpendicularly incident on the substrate surface causes irregular reflection on the inclined surface of the step portion. There is a disadvantage that the pattern of the thin line portion cannot be accurately reproduced.

Therefore, in order to prevent such halation,
Various methods have been tried so far. As one of them, a compound in which a light-absorbing dye, for example, a specific azo compound having at least one hydroxyl group in a molecule is blended with a photoresist is known (JP-A-59-142538).

However, although the photoresist to which this light-absorbing dye is added significantly improves the antihalation effect as compared with the conventional photoresist, the photoresist has a slight halation in order to cope with the rapid miniaturization of processing dimensions in the recent semiconductor industry. Is also a problem and is not always fully satisfactory. Further, on a substrate having a step, the thickness of the positive photoresist to be applied is different between the step protrusion and the recess, and the thin film portion on the step protrusion has a smaller film thickness than the thick film on the recess. Due to the tendency to overexposure, even a slight halation may cause the resist pattern in the thin part to become thinner during development, deform the cross-sectional shape of the pattern, or deteriorate the dimensional stability of the resist pattern during development. In addition, not only has the disadvantage that the resist pattern is broken when the resist pattern is fine, it is not possible to cope with the formation of a fine pattern, but also the light-absorbing dye is added to the photoresist to prevent halation. When light is added, the light-absorbing dye absorbs actinic light during exposure, lowers the sensitivity of the photoresist, and reduces the throughput in the manufacturing process of semiconductor devices. That it is not practical cause.

Further, a method of forming a resist pattern having excellent dimensional stability by a so-called multilayer method of forming an organic film having an action of preventing halation and flattening on a substrate is also known. However, this method has many processes. Process
Scanning is inevitably complicated.

Further, a photoresist composition using 1,2-naphthoquinodiazide sulfonic acid ester of curcumin as a photoactive compound has been disclosed (Japanese Patent Application Laid-Open No. 63-26741 / 1988). Since the lightness is extremely poor, the exposure time must be lengthened, and the cross-sectional shape of the obtained resist pattern tends to be susceptible to pulling, and has the disadvantage that the profile shape is poor.

Therefore, in order to cope with recent microfabrication, it is possible to form a resist pattern with good dimensional stability in a single layer, and has a high antihalation effect and high sensitivity.
There is a strong demand for the development of a positive photosensitive composition having an excellent profile.

SUMMARY OF THE INVENTION The present invention overcomes the above-mentioned drawbacks of the prior art in order to cope with the rapidly progressing miniaturization of processing dimensions in the field of semiconductor device manufacturing, and to improve the profile shape and dimensional stability. An object of the present invention is to provide a positive photosensitive composition which can form an excellent resist pattern and has a high antihalation effect and high sensitivity.

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, a 1,2-naphthoquinonediazidosulfonic acid ester of a specific azomethine compound was added to a conventional poly-type photoresist. By doing so, they found that the object could be achieved, and based on this finding, completed the present invention.

That is, the present invention relates to (A) a positive photoresist,
(B) General formula (Wherein R ¹ is a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, R ² is a hydrogen atom, a halogen atom,
A nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, each of R ³ and R ⁴ is an alkyl group having 1 to 3 carbon atoms, Or a different type of azomethine compound represented by the formula (1), wherein the azomethine compound is 1,2-naphthoquinonediazidosulfonic acid ester.

 Hereinafter, the present invention will be described in detail.

In the composition of the present invention, the positive photoresist used as the component (A) is not particularly limited, and can be arbitrarily selected from commonly used ones.
Preferred examples include those comprising a photosensitive substance and a film-forming substance.

As the photosensitive substance, a quinonediazide group-containing compound, for example, orthobenzoquinonediazide, orthonaphthoquinonediazide, orthoanthraquinonediazide and the like, a sulfonic acid of a quinonediazide and a compound having a phenolic hydroxyl group or an amino group, or Partially or completely amidated ones are mentioned.Examples of the compound having a phenolic hydroxyl group or an amino group include, for example, 2,3,4-trihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, Polyhydroxybenzophenone such as 2,3,4,4'-tetrahydroxybenzophenone, or alkyl gallate, aryl gallate, phenol, p-methoxyphenol, dimethylphenol, hydroquinone,
Bisphenol A, naphthol, pyrocatechol, pyrogallol, pyrogallol monomethyl ether, pyrogallol-1,3-dimethylether, gallic acid, gallic acid esterified or etherified leaving some hydroxyl groups, aniline, p-aminodiphenylamine and the like. .

Examples of the film-forming substance blended in the positive photoresist include, for example, a novolak resin obtained from phenol, cresol or xylenol, and an aldehyde, an acrylic resin, a copolymer of styrene and acrylic acid, and a polymer of hydroxystyrene. An alkali-soluble resin such as coalescing, polyvinylhydroxybenzoate, and polyvinylhydroxybenzal is effective.

Preferred positive photoresists in the composition of the present invention include those using a cresol novolak resin as a film-forming substance. Particularly preferred cresol novolak resins are those obtained from a mixed cresol of 10-45% by weight of m-cresol and 90-55% by weight of p-cresol. As a more preferred cresol novolak resin, a mixture of the following two types of cresol novolak resins, that is, m
A weight average molecular weight of 5000 obtained from a mixed cresol of 60 to 80% by weight of cresol and 40 to 20% by weight of p-cresol
The cresol novolak resin described above (in terms of polystyrene), m-cresol 10 to 40% by weight and p-cresol 90 to
A cresol novolak resin having a weight average molecular weight of 5,000 or less (in terms of polystyrene) obtained from a mixed cresol with 60% by weight of m-cresol 30 to 46.5 in terms of cresol.
% And 70 to 53.5% by weight of p-cresol. In addition, m-cresol and p-cresol are used for the production of these cresol novolak resins, but those containing o-cresol, xylenol and the like can be used as necessary.

By using such a cresol novolak resin as a film-forming substance, a resist pattern having more excellent 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
It is blended in a ratio of 10 to 40% by weight. If this amount is less than 10% by weight, it is difficult to obtain a resist pattern having a desired cross-sectional shape, which is not practical. If it exceeds 40% by weight, sensitivity tends to be remarkably deteriorated, which is not preferable.

In the composition of the present invention, the component (B) is added to the positive photoresist of the component (A) by a general formula (Wherein R ¹ , R ² , R ³ and R ⁴ have the same meanings as described above). It is necessary to compound 1,2-naphthoquinonediazidosulfonic acid ester of an azomethine compound represented by the following formula:

Such an ester is, for example, an azomethine compound represented by the above general formula (I) and 1,2-naphthoquinonediazide-4-sulfonic acid or 1,2-naphthoquinonediazide-
It can be obtained as a reaction product by an esterification reaction with 5-sulfonic acid. Specifically, an azomethine compound represented by the general formula (I) and 1,2-naphthoquinonediazide-4-sulfonyl chloride or 1,2-naphthoquinonediazide-5-sulfonyl chloride are mixed with a suitable solvent such as N, N- It can be produced by dissolving in dimethylacetamide or the like and subjecting it to an esterification reaction in the presence of a catalyst such as triethanolamine. Examples of the azomethine compound represented by the general formula (I) include 4-hydroxy-4'-diethylaminobenzylideneaniline, 3-hydroxy-4'-diethylaminobenzylideneaniline, 2-hydroxy-4'-diethylaminobenzylideneaniline, , 4-dihydroxy-4'-
Diethylaminobenzylideneaniline, 5-chloro-2
-Hydroxy-4'-diethylaminobenzylideneaniline, 4-hydroxy-3-nitro-4'-diethylaminobenzylideneaniline, 4-hydroxy-2-methyl-4'-diethylaminobenzylideneaniline, 3-
Examples thereof include hydroxy-4-methoxy-4'-diethylaminobenzylideneaniline and 4-hydroxy-4'-dimethylaminobenzylideneaniline. Among these azomethine compounds, 4-hydroxy-4'-dimethylaminobenzylidene is particularly preferred. Aniline, 4-
Hydroxy-4'-diethylaminobenzylideneaniline and 2,4-dihydroxy-4'-diethylaminobenzylideneaniline are preferred. These azomethine compounds may be used alone or in combination of two or more.

The component (B) in the composition of the present invention has the above general formula (I)
As the 1,2-naphthoquinonediazide sulfonic acid ester of the azomethine compound represented by the formula (I), an esterification reaction product obtained by the above-mentioned production method is usually used, and the average degree of esterification is 55% or more, preferably 75% or more. % Or more is advantageously used. Average degree of esterification
If it is less than 55%, it is difficult to form a resist pattern having a good sectional shape, which is not preferable. The average degree of esterification of the esterification reaction product can be calculated by analysis using liquid chromatography.

In the composition of the present invention, the naphthoquinonediazidesulfonic acid ester of the component (B) is used as a solid component of the positive photoresist of the component (A) (total of the photosensitive substance and the film-forming substance contained in the positive photoresist). The amount is preferably 0.5 to 20% by weight, and more preferably 1 to 10% by weight. If the amount is less than 0.5% by weight, the effect of preventing halation will not be sufficiently exhibited.
Exceeding the weight percentage tends to change the cross-sectional shape of the resist pattern, which is not preferable.

In the positive photosensitive composition of the present invention, if necessary, other compatible dyes such as curcumin and coumarin-based dyes may be added, and further, other additives such as additional A commonly used material such as a resin, a plasticizer, a stabilizer or a coloring agent for making the pattern obtained by development more visible can be added.

The positive photosensitive composition of the present invention is prepared by adding an appropriate solvent to the photosensitive substance, the film-forming substance, the esterified product of the azomethine compound represented by the general formula (I), and optional components used as necessary. Are dissolved in the respective required amounts and used in the form of a solution.

Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexane, isoamyl ketone: ethylene glycol, propylene glycol,
Polyhydric alcohols such as ethyne glycol monoacetate, diethylene glycol or diethylene glycol monoacetate, such as monomethyl ether, monoethyl ether, monopropyl ether, monoisopropyl ether, monobutyl ether or monophenyl ether, and derivatives thereof: cyclic ethers such as dioxane : Esters such as methyl acetate, ethyl acetate and ethyl butyl lactate: and aprotic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methyl-2-pyrrolidone. . These may be used alone or as a mixture of two or more.

Next, an example of a preferred method of using the composition of the present invention will be described. First, the film-forming substance, the photosensitive substance, and the azomethine represented by the general formula (I) are formed on a substrate such as a silicon wafer. After applying a solution in which 1,2-naphthoquinonediazidosulfonic acid ester of the compound and various dyes to be added as necessary and additives are dissolved in the above-mentioned solvent by a spinner or the like, and drying to form a photosensitive layer,
Exposure is performed through a required mask using a reduction projection exposure apparatus or the like. Then, this is developed using a developing solution, for example, an aqueous solution of 2 to 5% by weight of tetramethylammonium hydroxide or choline, so that the portion solubilized by exposure is faithfully conformed to the mask pattern in which the portion selectively dissolved and removed. Image can be obtained.

Effect of the Invention The positive photosensitive composition of the present invention is prepared by adding a 1,2-naphthoquinonediazidosulfonic acid ester of a specific azomethine compound to a positive photoresist and blending the same with an alkali developing solution in an active light exposure area. In addition, the solubility can be improved, and conversely, the solubility in the alkali developing solution in the non-exposed area can be suppressed, so that a resist pattern having extremely excellent dimensional stability and dimensional accuracy can be obtained. Compared with various conventional additives used to prevent halation, the 1,2-naphthoquinonediazidosulfonic acid ester of the specific azomethine compound used in the present invention is:
Even if it is added to a positive photoresist, it does not lower the sensitivity of the photoresist, so that it is extremely practical without lowering the throughput in the manufacturing process of semiconductor devices and the like.

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

Production Example 1 4-hydroxy-4'-diethylaminobenzylideneaniline (10 g) and 1,2-naphthoquinonediazide-5-sulfonyl chloride (8.1 g) were mixed with N, N-dimethylacetamide (350 g).
And 8 g of triethanolamine dissolved in 32 g of N, N-dimethylacetamide was added dropwise thereto over 1 hour with sufficient stirring. Then 35% by weight hydrochloric acid 25
The reaction product was precipitated by adding a dilute hydrochloric acid solution diluted with 1000 g of ion-exchanged water to precipitate a reaction product.The resulting precipitate was thoroughly washed with ion-exchanged water, dried after removing water, and dried.
An ester of 4'-diethylaminobenzylideneaniline (average degree of esterification 80%) was obtained.

Production Example 2 In Production Example 1, 1,2-naphthoquinonediazide-5
An esterified product (average degree of esterification: 25%) was obtained in the same manner as in Production Example 1 except that the amount of -sulfonyl chloride used was changed to 2.7 g.

Production Example 3 In Production Example 1, 1,2-naphthoquinonediazide-4
Example 1 except that 5.4 g of sulfonyl chloride were used
In the same manner as above (esterification degree 50%)
I got

Production Example 4 In Production Example 1, 1,2-naphthoquinonediazide-4
-An esterified product (average degree of esterification of 100) was prepared in the same manner as in Production Example 1 except that 10.8 g of sulfonyl chloride was used.
%).

Production Example 5 In Production Example 1, 4-hydroxy-3-nitro-
An esterified product (average degree of esterification: 75%) was obtained in the same manner as in Production Example 1 except that 10 g of 4'-diethylaminobenzylideneaniline was used.

Example 1 Cresol novolak resin and o- as photosensitive material
Using OFPR-800 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd .: solid content 27% by weight) which is a positive photoresist containing a naphthoquinonediazide compound, and using the solid content, the esterified product obtained in Production Example 1 After blending 3% by weight, the solution was filtered through a membrane filter to prepare a coating solution. This coating solution was applied on a 4-inch silicon wafer having a step of 1.0 μm on a substrate on which aluminum was vapor-deposited to a thickness of 2.0 μm using a spinner and then placed on a hot plate at 110 ° C. For 90 seconds to form a film.

Next, the coating film on the substrate was exposed through a test chart mask using a reduced projection exposure apparatus 1505G3A type wafer stepper (manufactured by Nikon Corporation), and then exposed to a 2.38 wt% tetramethylammonium hydroxide aqueous solution at 23 ° C. For 30 seconds to form a resist pattern on the substrate. When this pattern was observed with an electron microscope, a 0.8 μm pattern faithful to the mask was formed even on the step protrusion having a relatively thin coating film thickness, and the cross-sectional shape was a vertical and extremely sharp pattern. Was.

When the minimum exposure time for obtaining a 1.0 μm line and space pattern was measured as the sensitivity,
160 ms.

Example 2 As a film forming substance used for a positive photoresist, m
-Cresol and p-cresol are mixed at a weight ratio of 60:40, formalin is added thereto, and the mixture is condensed by an ordinary method using an oxalic acid catalyst to give a cresol novolak resin (I) having a weight average molecular weight of 28,000. After that, m-cresol and p-cresol were similarly mixed at a weight ratio of 40:60 and condensed to obtain a cresol novolak resin (II) having a weight average molecular weight of 2,000.

30 parts by weight of resin (I), 70 parts by weight of resin (II), 2,3,4-
1 mol of trihydroxybezophenone and naphthoquinone-1,2
Reaction product 30 with 1.6 mol of diazidesulfonic acid chloride
3 parts by weight of the esterified product obtained in Production Example 1 was dissolved in 390 parts by weight of ethyl lactate with respect to parts by weight and the solid content thereof, and then filtered using a 0.2 μm membrane filter to prepare a coating solution. Using this coating solution, a resist pattern was formed in the same manner as in Example 1. When this resist pattern was observed with an electron microscope, it was as excellent as in Example 1.

When the minimum exposure time was measured in the same manner as in Example 1, it was 180 ms.

Example 3 A resist pattern was formed in the same manner as in Example 1 except that 3% by weight of the esterified product obtained in Production Example 3 was used instead of the esterified product obtained in Production Example 1. As a result, a sharp resist pattern having an excellent sectional shape was obtained.

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

Example 4 A resist pattern was formed in the same manner as in Example 1 except that the esterified product (Production Example 1) used in Example 1 was replaced by 3% by weight of the esterified product obtained in Production Example 2. In the resist pattern on the flat surface on the substrate, a relatively sharp pattern was obtained, but in the resist pattern at the step portion, some halation from the lateral direction was confirmed.

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

Example 5 A resist pattern was formed in the same manner as in Example 2 except that the esterified product (Production Example 1) used in Example 2 was replaced by 8% by weight of the esterified product obtained in Production Example 4. A pattern faithful to the mask was formed, and the cross-sectional shape was a vertical and extremely sharp resist pattern.

The minimum exposure time measured in the same manner as in Example 1 was 200 ms.

Example 6 A resist pattern was formed in the same manner as in Example 2 except that 5% by weight of the esterified product obtained in Production Example 5 was used instead of the esterified product (Production Example 1) used in Example 2. A pattern faithful to the mask was formed, and the cross-sectional shape was a vertical and extremely sharp resist pattern.

The minimum exposure time measured in the same manner as in Example 1 was 190 ms.

Claims (2)

(57) [Claims] 1. A method according to claim 1, wherein (A) a positive photoresist and (B) a general formula (R ¹ in the formula is a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms or 1 carbon atom.
To 3 alkoxy groups, R ² is a hydrogen atom, a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms, and R ³ and R ⁴ each have a carbon number of 1 to 3 alkyl groups, which may be the same or different from each other). Positive-type photosensitive composition comprising 1,2-naphthoquinonediazidosulfonic acid ester of an azomethine compound represented by the formula: Composition. 2. The positive photosensitive composition according to claim 1, wherein the compounding amount of the 1,2-naphthoquinonediazidosulfonic acid ester of the azomethine compound is 0.5 to 20% by weight based on the solid content of the positive photoresist.