JPH07140647A - Positive resist composition - Google Patents

Abstract

PURPOSE:To obtain a positive resist composition excellent in film forming property, preservable stability and step coverage property and also, excellent in safety. CONSTITUTION:The positive resist composition is obtained by dissolving an alkali soluble resin (A) and a quinone diazide group containing compound (B) in a solvent mixture (C) of an alkyl 2-oxypropionate (a) with a propylene glycol monoalkyl ether acetate (b) and if necessary, a hydrocarbon based organic solvent (c).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel positive resist composition, more specifically, excellent coating film properties, storage stability, step coverage properties, and safety properties, which are preferably used in the production of electronic component materials. It also relates to an excellent positive resist composition.

[0002]

2. Description of the Related Art In the manufacture of electronic component materials such as semiconductor devices and liquid crystal display devices, a pattern transfer method by photolithography is used as a method for forming a pattern on a substrate. In this photolithography, a resist is applied on a substrate such as a silicon wafer using a spinner, dried, and then irradiated with an actinic ray through a mask and developed to transfer a mask pattern onto the substrate, and then etching. Is. The resist used as the mask for this etching was initially of the negative type, but the negative type resist is currently used because of the problem of resolution limit due to expansion in the developing solution and mask damage in contact exposure. A positive resist having excellent image quality is often used.

By the way, in recent years, silicon wafers and glass substrates have become large in size, and it is desired that a coating film have excellent uniformity in coating a resist on the substrate. When forming a coating film, the smaller the film thickness difference between the coating film formed on the concave portion and the coating film formed on the convex portion, the better the resist pattern formed. Therefore, it is required that the difference in the film thickness of the coating film is small, that is, that the step coverage is excellent, and the impact of chemicals on the environment and the human body is a big problem, and it does not adversely affect the environment and health. There is a strong demand for a resist that does not harm the above, and various studies have been conducted on the resist solvent.

Conventionally, many solvents are known as solvents for positive resists, such as ethylene glycol monoethyl ether acetate, cyclopentanone (JP-A-59-155838), and monooxymonocarboxylic acid esters. (JP-A-62-123444), a mixed solvent of cyclic ketone and alcohol (US Pat. No. 452).
6856), propylene glycol alkyl ether (JP-A-61-7837) and the like, but none of the solvents has poor uniformity and step coverage, and cannot be said to have good coatability. In addition, some solvents have a bad effect on the environment and the human body, so that they are inferior in practical use.

[0005]

The present invention solves the problems of such a positive resist composition using a conventional solvent, is excellent in coating property, storage stability, and step coverage property, and The purpose of the present invention is to provide a positive resist composition having excellent safety.

[0006]

As a result of intensive studies to develop a positive resist composition having the above-mentioned preferable properties, the present inventors have identified an alkali-soluble resin and a quinonediazide group-containing compound as specific compounds. It was found that the object can be achieved when dissolved in a mixed solvent, and the present invention has been completed based on this finding.

That is, the present invention comprises (A) an alkali-soluble resin and (B) a quinonediazide group-containing compound.
(C) (a) alkyl 2-oxypropionate and (b)
The present invention provides a positive resist composition dissolved in a mixed solvent with propylene glycol monoalkyl ether acetate.

Examples of the alkali-soluble resin used as the component (A) in the composition of the present invention include novolac resins, acrylic resins, copolymers of styrene and acrylic acid, polymers of hydroxystyrene, polyvinylphenol, poly α. -Methyl vinylphenol and the like are mentioned, and among them, alkali-soluble novolac resin is particularly preferable. The alkali-soluble novolak resin is not particularly limited, and those conventionally used as film-forming substances in positive photoresist compositions, such as aromatic hydroxy compounds such as phenol, cresol, and xylenol, and aldehydes such as formaldehyde are used. Those condensed in the presence of an acidic catalyst are used. The alkali-soluble novolac resin has a weight average molecular weight of 2,000 to 20,000 with the low molecular weight region cut.
The range of 5000 to 15000 is preferable.

In the composition of the present invention, a quinonediazide group-containing compound is used as the photosensitive component of the component (B). Examples of the quinonediazide group-containing compound include orthobenzoquinonediazide, orthonaphthoquinonediazide, sulfonic acids of quinonediazides such as orthoanthraquinonediazide, and partial or complete esterification of a compound having a phenolic hydroxyl group or an amino group,
Alternatively, a partially or completely amidated product may be used. Examples of the compound having a phenolic hydroxyl group or an amino group include 2,3,4-trihydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone and 2,3,4,4'-tetrahydroxybenzophenone. Polyhydroxybenzophenone, alkyl gallate, aryl gallate, phenol, phenolic resin, p-methoxyphenol, dimethylphenol, hydroquinone, polyhydroxydiphenylalkane, polyhydroxydiphenylalkene, bisphenol A, α, α ′, α ″ -tris (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, 1-
[1- (4-hydroxydiphenyl) isopropyl]-
4- [1,1-bis (4-hydroxydiphenyl) ethyl] benzene, tris (hydroxyphenyl) methane or its methyl-substituted product, naphthol, pyrocatechol, pyrogallol, pyrogallol monomethyl ether, pyrogallol 1,3-dimethyl ether, gallic acid , Gallic acid esterified or etherified with some hydroxyl groups left,
Examples thereof include aniline and p-aminodiphenylamine. A particularly preferred quinonediazide group-containing compound is a complete or partial esterification product of polyhydroxybenzophenone and naphthoquinone-1,2-diazide-5-sulfonic acid or naphthoquinone-1,2-diazide-4-sulfonic acid, and Average degree of esterification is 70 mol%
The above is preferable. Further, as the polyhydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone is preferable, and the quinonediazide group-containing compound including the esterified product synthesized from this compound has excellent compatibility with the mixed solvent described later. Particularly preferred.

In the composition of the present invention, the above-mentioned quinonediazide group-containing compound may be contained alone or in combination of two or more as the photosensitive component.

This quinonediazide group-containing compound is obtained by using, for example, the above-mentioned polyhydroxybenzophenone, naphthoquinone-1,2-diazide-5-sulfonyl chloride or naphthoquinone-1,2-diazide-4-sulfonyl chloride in a suitable solvent such as dioxane. It can be produced by condensing in the presence of an alkali such as triethanolamine, an alkali carbonate or an alkali hydrogen carbonate, and performing complete esterification or partial esterification.

In the composition of the present invention, a mixed solvent of (a) alkyl 2-oxypropionate and (b) propylene glycol monoalkyl ether acetate is used as the solvent for component (C).

Examples of the (2-) component alkyl 2-oxypropionate include methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate, and the like. Particularly preferred is ethyl 2-oxypropionate.
Further, these alkyl 2-oxypropionates may be used alone or in combination of two or more kinds.

Examples of the propylene glycol monoalkyl ether acetate used as the component (b) include those whose alkyl group is methyl, ethyl, propyl, butyl, etc., and propylene glycol monomethyl ether acetate is particularly preferable. . In addition, these propylene glycol monoalkyl ether acetates may be used alone or in combination of two or more kinds.

In the present invention, a mixed solvent of the above-mentioned (a) component and (b) component may be added, and if necessary, (c)
A hydrocarbon organic solvent can be added as a component. The hydrocarbon-based organic solvent is preferably an aromatic hydrocarbon-based solvent such as xylene, whereby the solubility of the alkali-soluble resin or the quinonediazide group-containing compound can be improved, and the positive resist composition has good storage stability. Can be prepared.

Regarding the mixing ratio of each component in the mixed solvent used in the composition of the present invention, in the case of containing the two components (a) and (b), the component (a) is 10
To 90 wt% and (b) component 90 to 10 wt% are preferable, and when three components of (a) component, (b) component and (c) component are contained, (a) component 10 ~ 90 wt%, (b) component 5 to 80 wt% and (c) component 5-1
It preferably contains 0% by weight. If the mixing ratio of each component deviates from the above range, it is not preferable because a positive resist composition having improved coating property, storage stability, step coverage property, and safety, which is the object of the present invention, cannot be obtained.

The composition of the present invention may further contain a compatible additive such as an additional resin, a plasticizer, a stabilizer or a pattern obtained by development for improving the performance of the resist film. A colorant for making it more visible, a sensitizer for further improving the sensitizing effect, and a commonly used one such as a contrast improving agent can be added and blended.

The composition of the present invention is added to the above-mentioned mixed organic solvent,
It is advantageous to dissolve the alkali-soluble resin, the quinonediazide group-containing compound, and the additional components to be blended, if necessary, in the required amounts and use them in the form of a solution.

About the preferred method of using the composition of the present invention 1
For example, first, on a substrate such as a silicon wafer,
A solution obtained by dissolving an alkali-soluble resin and a quinonediazide group-containing compound in the above-mentioned mixed organic solvent is applied by a spinner, a roll coater or the like and dried to form a photosensitive layer, and then a light source that emits ultraviolet rays, for example, low pressure. Use a mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an arc lamp, a xenon lamp, etc. to expose through a required mask pattern, a reduction projection exposure device, or an excimer laser or X-ray through the mask pattern. Alternatively, the electron beam is emitted while scanning. Next, when this is immersed in a developing solution, for example, an alkaline aqueous solution such as a 1-10 wt% tetramethylammonium hydroxide aqueous solution, the portion solubilized by exposure is selectively dissolved and removed, and an image faithful to the mask pattern is obtained. Can be obtained.

Such a pattern is not limited to semiconductor processing, but is applied in fields where lithography is used, such as LC.
The same excellent effect can be obtained for D, TAB, PCB, chemical milling, printing and the like. In particular, the composition of the present invention could not obtain a coating film excellent in uniformity with a conventional organic solvent, and when applied to a large substrate or a rectangular substrate, a very high coating film can be easily obtained. Produce an effect.

[0021]

The positive resist composition of the present invention uses a mixed solvent of alkyl 2-oxypropionate, propylene glycol monoalkyl ether acetate and optionally a hydrocarbon organic solvent as a preparation solvent. By doing so, it is possible to form a coating film having excellent coating properties, storage stability, and step coverage,
Further, the prepared solvent is extremely effective in practice because it does not adversely affect the environment and the human body.

[0022]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The physical properties in each example are obtained by the following methods. (1) Uniformity A coating solution of a positive resist composition was coated on a 6-inch silicon wafer at 3000 rpm for 20 seconds, and the coating was performed at 90 ° C. for 9 minutes.
A coating film is formed by drying on a hot plate for 0 seconds, and the film thickness of the coating film is measured over the entire surface of the wafer. When the variation in film thickness on the wafer is ± 20Å or less, ○, ± 21 to Those with 40 Å were evaluated as Δ, and those with ± 41 Å or more were evaluated as x.

(2) Storage stability A coating solution of the prepared positive resist composition was applied to 0.2 μm.
After being filtered through a membrane filter of No. 3 and allowed to stand at 40 ° C. for 3 months, the presence or absence of precipitates in the solution was observed.

(3) Step Coverage Property A coating solution of the positive resist composition was applied onto a 6-inch silicon wafer on which a silicon oxide film pattern having a film thickness of 0.5 μm was formed in a line and space having a width of 2.0 μm.
It is applied by a spinner so that the dry film thickness on a flat surface without a silicon oxide film pattern is 1.5 μm, and dried to form the applied film on the entire surface of the wafer. The difference between the film thickness and the film thickness of the coating film formed on the space portion was measured, and the difference was 0.10.
∘ for μm or less, Δ for 0.11 to 0.20
Those having 0.21 μm or more were evaluated as x.

Example 1 2,3,4,4'-tetrahydroxybenzophenone 1
Mole of naphthoquinone-1,2-diazide-5-sulfonyl chloride (3 moles), a mixed solvent of 2 g of an esterification reaction product and 8 g of cresol novolac resin with 40 g of ethyl 2-oxypropionate and 10 g of propylene glycol monomethyl ether acetate. To prepare a coating solution of the positive resist composition. The physical properties of this coating solution were examined, and the results are shown in Table 1.

Examples 2 to 7 and Comparative Examples 1 to 2 Coating solutions of positive resist compositions were prepared in the same manner as in Example 1 except that the mixed solvent shown in Table 1 was used.
The physical properties of this coating solution were examined, and the results are shown in Table 1.

[0028]

[Table 1]

Example 8 40 g of ethyl 2-oxypropionate, 5 g of propylene glycol monomethyl ether acetate and 5 of xylene
A positive resist composition coating solution was prepared in the same manner as in Example 1 except that the mixed solvent consisting of g was used. When the physical properties of this coating solution were examined and evaluated, the uniformity was ◯, the storage stability was not found, and the step coverage was ◯.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Koichi Takahashi, 150 Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa Tokyo Ohka Kogyo Co., Ltd. (72) Hidekatsu Ohara 150, Nakamaruko, Nakahara-ku, Kawasaki, Kanagawa Higashi Kyoka Industrial Co., Ltd. (72) Inventor Hisasamu Nakayama 150 Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa Tokyo Ohka Kogyo Co., Ltd.

Claims (5)

[Claims] 1. A mixed solvent of (A) an alkali-soluble resin and (B) a quinonediazide group-containing compound, (C) (a) an alkyl 2-oxypropionate and (b) a propylene glycol monoalkyl ether acetate. A positive resist composition prepared by dissolving in. 2. An alkali-soluble resin (A) and a quinonediazide group-containing compound (B) are added to (C) (a) alkyl 2-oxypropionate, (b) propylene glycol monoalkyl ether acetate and (c) carbonized. A positive resist composition which is dissolved in a mixed solvent with a hydrogen-based organic solvent. 3. An alkyl 2-oxypropionate is 2
-The positive resist composition according to claim 1 or 2, which is ethyl oxypropionate. 4. The positive resist composition according to claim 1, wherein the propylene glycol monoalkyl ether acetate is propylene glycol monomethyl ether acetate. 5. The quinonediazide group-containing compound is 2,
A product comprising an esterification reaction product of 3,4,4'-tetrahydroxybenzophenone and naphthoquinone-1,2-diazide-4-sulfonic acid or naphthoquinone-1,2-diazide-5-sulfonic acid. The positive resist composition as described in any one of 4 above.