JP3453615B2 - Positive photoresist composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel positive photoresist composition. More specifically, the present invention relates to a positive photoresist composition suitable for wet etching treatment or dry etching treatment using various acids, oxidizing agents, reducing agents and the like.

[0002]

2. Description of the Related Art In recent years, display devices such as industrial computers, printer heads, etc. have become larger and finer, and along with this, materials such as metals, metal oxides or nitrides, or plastics. Precision has come to be required in the photo-etching process applied to the. For example, the processing accuracy is required to be about 10 μm to 5 μm. For this reason, it is required for the positive photoresist composition in this field to reduce the side etch amount at the time of etching as much as possible in addition to achieving excellent resolution.

A normal positive photoresist composition is composed of an alkali-soluble novolac resin and a photolytic component, that is, a photosensitizer, and naphthoquinone diazide sulfonate is used as the photosensitizer ( U.S. Pat. No. 3,402,044).
In addition, various compounds have been known so far for such naphthoquinone diazide sulfonates (US Pat. Nos. 3,046,118, 3,106,465, and 3,148,983).

On the other hand, regarding the alkali-soluble novolac resin, for example, use of phenol-formaldehyde novolac resin is disclosed (US Pat. No. 3,402,044).
), And examples of use of cresol novolac resin have been reported ["Electrochemistry and Industrial Physical Chemistry", No.
Volume, p. 584 (1980)]. Further, it is also known that a highly sensitive positive photoresist can be obtained by appropriately selecting the compounding ratio of the cresol isomer during the production of the cresol novolac resin.

However, in the conventional positive photoresist, there is a drawback that the side etching amount in the photoetching process is unavoidably larger than the theoretical value because the acid resistance and the adhesion to the substrate are insufficient. is there.

Therefore, for example, in the etching process of a transparent conductive film such as a liquid crystal display body in which the miniaturization and the size increase of the base material are being advanced at present, the positive type photoresist having an extremely small side etch amount and excellent acid resistance is used. Development is desired.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel positive photoresist composition which overcomes the drawbacks of the conventional positive photoresist.

An object of the present invention is to provide a positive photoresist composition which is excellent in acid resistance and adhesion to a substrate.

An object of the present invention is to provide a positive photoresist composition capable of reducing the side etch amount of photoresist in the photoetching process of various materials such as metal and metal oxide film as much as possible.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that cresol novolak resins having a specific weight average molecular weight of o-
It has been found that the above problems can be achieved by using a cresol novolac resin. The present invention has been completed based on such findings. 1. The present invention relates to a positive photoresist composition containing a cresol novolac resin and a photosensitizer containing naphthoquinone diazide sulfonic acid ester as a main component, and o-cresol having a weight average molecular weight (Mw) of 16,000 to 75,000 as the cresol novolac resin. A positive photoresist composition comprising a novolac resin. 2. The present invention is the positive photoresist composition as described in 1 above, wherein the o-cresol novolac resin has a weight average molecular weight (Mw) of 16500 to 70,000. 3. The present invention is the positive photoresist composition as described in 1 above, wherein the o-cresol novolac resin has a weight average molecular weight (Mw) of 17,000 to 60,000. 4. The present invention is the positive photoresist composition as described in 1, 2, or 3 above, which comprises 10 to 50 parts by weight of a photosensitizer per 100 parts by weight of the o-cresol novolac resin.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the cresol novolak resin has a weight average molecular weight (polystyrene-equivalent weight average molecular weight by high performance liquid chromatography) of 1
It is essential to use 6000-75000 o-cresol novolac resin.

The object of the present invention cannot be achieved with o-cresol novolac resins other than o-cresol novolac resins having a weight average molecular weight of 16,000 to 75,000. For example, with an o-cresol novolac resin having a weight average molecular weight of less than 16,000, both acid resistance and adhesiveness to a substrate are insufficient, and there is a drawback that the side etching amount increases during etching. On the other hand, with an o-cresol novolac resin having a weight average molecular weight of more than 75,000, the sensitivity decreases and the adhesion to the substrate becomes extremely insufficient, resulting in the disadvantage that the side etching amount increases in the etching process. These facts
This is apparent from Comparative Examples 1 and 2 described below.

Weight average molecular weight 160 used in the present invention
0-75000 o-cresol novolac resin is
It is desirable that the unreacted monomer content is 2% by weight or less.

Further, the o-cresol novolac resin used in the present invention has a weight average molecular weight of 16500 to 7000.
It is preferably 0, and the weight average molecular weight is 17,000 to 6
More preferably, it is 0000.

As the photosensitizer in the present invention, those having naphthoquinone diazide sulfonic acid ester as a main component are used. This photo-sensitizer comprises an esterification reaction of naphthoquinone diazide sulfonic acid and a compound having a phenolic hydroxyl group according to a conventional method. By doing so, it can be easily manufactured.

Examples of the compound having a phenolic hydroxyl group include novolak resins such as phenol novolac resin and cresol novolac resin, polyhydroxybenzophenone such as tetrahydroxybenzophenone and trihydroxybenzophenone, hydroxystyrene, and the like.
Alkyl gallate, trihydroxybenzene monoethers, 2,2 ′, 4,4′-tetrahydroxydiphenylmethane, 4,4′-dihydroxyphenylpropane,
4,4'-dihydroxydiphenyl sulfone, 2,2 '
-Dihydroxy-1,1-naphthylmethane, 2-hydroxyfluorene, 2-hydroxyphenanthrene, polyhydroxyanthraquinone, purprogarin and its derivatives, phenyl-2,4,6-trihydroxybenzoic acid ester, trisphenol and the like. The weight average molecular weight of the novolac resin used here is 500 to
About 3000 is good.

In the composition of the present invention, the photosensitizer containing the naphthoquinone diazitosulfonic acid ester as a main component is blended in an amount of 10 to 50 parts by weight based on 100 parts by weight of the o-cresol novolac resin. It is more preferable to add 15 to 40 parts by weight. The photoresist composition of this blending amount is a positive type photoresist composition that is extremely excellent in acid resistance and adhesion to a base material, and can minimize the side etch amount of photoresist in the photoresist etching processing of various materials such as metal and metal oxide film. It can be a thing.

The positive photoresist composition of the present invention is usually used in the form of a solution by dissolving the o-cresol novolac resin and the photosensitizer in a suitable solvent. As an example of such a solvent, any solvent used in this field can be used. Examples of such a solvent include acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and other ketones; ethylene glycol, ethylene glycol monoacetate, diethylene glycol, or diethylene glycol monoacetate monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, Examples thereof include polyhydric alcohols such as monophenyl ether and derivatives thereof; cyclic ethers such as dioxane; and esters such as ethyl acetate, butyl acetate, methyl lactate, ethyl lactate. These solvents may be used alone or in combination of two or more.

In the positive photoresist composition of the present invention, the solid content (total of o-cresol novolac resin and photosensitizer) is 1 per 100 parts by weight of the solvent.
About 0 to 100 parts by weight, preferably about 20 to 80 parts by weight may be added.

The positive photoresist composition of the present invention comprises
If desired, further compatible additive components, for example, epoxy resin or acrylic resin for improving strength, polyvinyl ethers or various plasticizers for imparting plasticity,
Stabilizers for imparting stability, various activators for improving the leveling property, or various dyes or pigments that are commonly used for making the developed image more visible may be contained. .

In producing the positive photoresist composition of the present invention, the above o-cresol novolac resin, photosensitizer and other additives may be dissolved in a suitable solvent. The order of addition of each component when dissolved in a solvent is not particularly limited.

Next, preferred examples of the method of using the positive photoresist composition of the present invention will be shown.

For example, a positive photoresist composition of the present invention for producing a wiring pattern by a subtractive method is applied on a copper clad laminate for a printed wiring board using a roll coater or the like and dried to form a photosensitive layer. After that, a test pattern mask is suction-adhered by using an ultraviolet irradiation device using an ultra-high pressure mercury lamp as a light source, exposure is performed, and a certain amount of ultraviolet rays are irradiated, and then a hydroxylation of 0.5 to 2 wt% concentration is performed. By developing with an alkaline developer such as an aqueous solution of sodium or potassium hydroxide, the portion solubilized by irradiation is selectively dissolved and removed, and a resist pattern faithful to the test pattern mask is formed on the laminate. Next, after the resist pattern is removed, copper is etched using an appropriate etching solution containing ferric chloride, cupric chloride, etc. as a main component, and then the photoresist composition on the laminate is treated with an alkaline stripping solution. A printed wiring board faithful to the pattern can be obtained by peeling it off and thoroughly washing with water.

[0024]

According to the present invention, there is provided a novel positive photoresist composition which overcomes the drawbacks of the conventional positive photoresist.

According to the present invention, there is provided a positive photoresist composition excellent in acid resistance and adhesion to a substrate.

According to the present invention, there is provided a positive photoresist composition capable of reducing the side etch amount of the photoresist in the photoetching process of various materials such as metal and metal oxide film as much as possible.

According to the present invention, there is provided a positive photoresist composition which is excellent in development stability and shows almost no decrease in development level even after long-term use or repeated use.

When peeling the positive photoresist composition of the present invention from the base, it is not necessary to use an expensive exclusive stripping solution containing an organic solvent, and an inexpensive inorganic alkali (sodium hydroxide, potassium hydroxide) is used. Etc.) can be used as the stripping solution.

[0029]

EXAMPLES The present invention will be further clarified with reference to production examples, examples, comparative examples and test examples below.

Production Example 1 (Production of o-cresol novolac resin) (1) Production of o-cresol novolac resin (weight average molecular weight 12000) In a 2 liter four-necked flask equipped with a stirrer and a reflux condenser, o- Cresol 756 g, 37% formalin 36
9 g and 7.52 g of p-toluenesulfonic acid monohydrate as a reaction catalyst were charged, and while stirring and mixing these, the temperature was raised to the reflux temperature, and the reaction was continued under reflux for 12 hours.

Next, deliquoring was started, the temperature was raised to 230 ° C. for concentration, and further the temperature was raised to 240 ° C. under a reduced pressure of 2 kpa to perform concentration. The fraction was distilled off to obtain 600 g of solid o-cresol novolac resin having a softening point of 150 ° C.

The weight average molecular weight of the obtained o-cresol novolac resin (weight average molecular weight in terms of polystyrene by high performance liquid chromatography) was 12,000.

(2) Production of o-cresol novolak resin (weight average molecular weight 18000) A solid o-cresol novolac resin having a softening point of 160 ° C. was treated in the same manner as in (1) above except that 397 g of 37% formalin was used. 620 g were obtained.

The weight average molecular weight of the obtained o-cresol novolak resin (weight average molecular weight in terms of polystyrene by high performance liquid chromatography) was 18,000.

(3) Production of o-cresol novolac resin (weight average molecular weight 25000) Solid o-cresol novolac resin having a softening point of 170 ° C. was treated in the same manner as in the above (1) except that 510 g of 37% formalin was used. 660 g was obtained.

The weight average molecular weight of the obtained o-cresol novolak resin (polystyrene-equivalent weight average molecular weight by high performance liquid chromatography) was 25,000.

(4) Production of o-cresol novolak resin (weight average molecular weight 44000) A solid o-cresol novolac resin having a softening point of 175 ° C. was treated in the same manner as in the above (1) except that 624 g of 37% formalin was used. 695 g were obtained.

The weight average molecular weight of the obtained o-cresol novolak resin (polystyrene-equivalent weight average molecular weight by high performance liquid chromatography) was 44,000.

(5) Production of o-cresol novolac resin (weight average molecular weight 58000) Solid o-cresol novolac resin having a softening point of 180 ° C. was treated in the same manner as in the above (1) except that 681 g of 37% formalin was used. 705 g was obtained.

The weight average molecular weight of the obtained o-cresol novolak resin (polystyrene-equivalent weight average molecular weight by high performance liquid chromatography) was 58,000.

(6) Production of o-cresol novolac resin (weight average molecular weight 80,000) Using 709 g of 37% formalin, the degree of vacuum was 1.3 kp.
A softening point of 1
710 g of solid o-cresol novolac resin at 85 ° C
Got

The weight average molecular weight of the obtained o-cresol novolac resin (weight average molecular weight in terms of polystyrene by high performance liquid chromatography) was 80000.

Production Example 2 (Production of naphthoquinone diazide sulfonic acid ester) (1) Production of naphthoquinone diazide sulfonic acid ester of o-cresol novolac resin Under yellow light, an o-cresol novolac resin (the above Production Example 1 (2) was used). The obtained weight average molecular weight of 18,000 o-
Cresol novolac resin) 60 g and naphthoquinone diazide-5-sulfonyl chloride 26.8 g
-Dissolved in dioxane, stirred while warming to 40 ° C,
Triethylamine 10.2g and 1,4-dioxane 30
The mixed solution (g) was dropped for about 30 minutes. After continuing heating and stirring for an additional 1 hour, the mixture was cooled to room temperature, and the reaction solution was filtered to remove precipitates. The filtrate was poured into 2 liters of a 1% hydrochloric acid aqueous solution while stirring. The precipitated solid content was separated by filtration, washed with water until it became neutral, separated by filtration and dried with water to obtain 73.8 g of naphthoquinone diazide sulfonic acid ester of o-cresol novolac resin.

(2) Preparation of naphthoquinonediazide sulfonate of 2,3,4-trihydroxybenzophenone 2,3,4-in place of o-cresol novolac resin
33.8 g of naphthoquinone diazide sulfonic acid ester of 2,3,4-trihydroxybenzophenone was obtained in the same manner as in (1) above except that 13.0 g of trihydroxybenzophenone was used.

Example 1 100 parts by weight of o-cresol novolac resin (weight average molecular weight 18000) obtained in Production Example 1 (2) and 2,3,4-trihydroxybenzophenone obtained in Production Example 2 (2). 30 parts by weight of naphthoquinone diazide sulfonic acid ester of was dissolved in 300 parts by weight of ethylene glycol monoethyl ether acetate, and this solution was filtered through a membrane filter (pore size 1 μm) to prepare a positive photoresist composition.

Example 2 100 parts by weight of o-cresol novolac resin (weight average molecular weight 25000) obtained in Production Example 1 (3) and 2,3,4-trihydroxybenzophenone obtained in Production Example 2 (2). 30 parts by weight of naphthoquinone diazide sulfonic acid ester of was dissolved in 300 parts by weight of ethylene glycol monoethyl ether acetate, and this solution was filtered through a membrane filter (pore size 1 μm) to prepare a positive photoresist composition.

Example 3 100 parts by weight of o-cresol novolac resin (weight average molecular weight 44000) obtained in Production Example 1 (4) and 2,3,4-trihydroxybenzophenone obtained in Production Example 2 (2). 30 parts by weight of naphthoquinone diazide sulfonic acid ester of was dissolved in 300 parts by weight of ethylene glycol monoethyl ether acetate, and this solution was filtered through a membrane filter (pore size 1 μm) to prepare a positive photoresist composition.

Example 4 100 parts by weight of o-cresol novolac resin (weight average molecular weight 58000) obtained in Production Example 1 (5) and 2,3,4-trihydroxybenzophenone obtained in Production Example 2 (2). 30 parts by weight of naphthoquinone diazide sulfonic acid ester of was dissolved in 300 parts by weight of ethylene glycol monoethyl ether acetate, and this solution was filtered through a membrane filter (pore size 1 μm) to prepare a positive photoresist composition.

Comparative Example 1 100 parts by weight of o-cresol novolac resin (weight average molecular weight 12000) obtained in Production Example 1 (1) and 2,3,4-trihydroxybenzophenone obtained in Production Example 2 (2). 30 parts by weight of naphthoquinone diazide sulfonic acid ester of was dissolved in 300 parts by weight of ethylene glycol monoethyl ether acetate, and this solution was filtered through a membrane filter (pore size 1 μm) to prepare a positive photoresist composition.

Comparative Example 2 100 parts by weight of o-cresol novolac resin (weight average molecular weight 80,000) obtained in Production Example 1 (6) and 2,3,4-trihydroxybenzophenone obtained in Production Example 2 (2). 30 parts by weight of naphthoquinone diazide sulfonic acid ester of was dissolved in 300 parts by weight of ethylene glycol monoethyl ether acetate, and this solution was filtered through a membrane filter (pore size 1 μm) to prepare a positive photoresist composition.

Comparative Example 3 An attempt was made to prepare a positive photoresist composition by dissolving the naphthoquinone diazide sulfonic acid ester of o-cresol novolac resin obtained in Production Example 2 (1) in ethylene glycol monoethyl ether acetate. The sulfonic acid ester could not be dissolved in ethylene glycol monoethyl ether acetate, and a positive photoresist composition could not be prepared.

Example 5 A positive photoresist composition was prepared in the same manner as in Example 2 except that 10 parts by weight of naphthoquinone diazide sulfonic acid ester of 2,3,4-trihydroxybenzophenone obtained in Production Example 2 (2) was used. The thing was prepared.

Example 6 A positive photoresist composition was prepared in the same manner as in Example 2 except that 50 parts by weight of naphthoquinone diazide sulfonic acid ester of 2,3,4-trihydroxybenzophenone obtained in Production Example 2 (2) was used. The thing was prepared.

Test Example 1 Each of the positive photoresist compositions prepared in the above Examples 1 to 6 and Comparative Examples 1 and 2 was applied to a polished and degreased copper clad laminate using a roll coater to a uniform film thickness of 5 μm. After coating, it was dried with a warm air dryer at 80 ° C.

Next, a test chart mask having a line and space of 50 μm was suction-adhered by using an ultra-high pressure mercury lamp ultraviolet irradiation device, exposed (near 365 nm, illuminance 5.2 mW / cm ² ) and irradiated with ultraviolet rays for 60 seconds. did. 25 ° C. using a 1 wt% sodium hydroxide aqueous solution,
Immersion rocking development was carried out for 60 seconds, and it was observed whether the lines and spaces equivalent to those of the test chart mask could be reproduced (resist pattern reproducibility).

Further, the copper clad laminate patterned with the positive photoresist composition was treated with ferric chloride hexahydrate 4
Etching was performed with an etching machine (temperature: 50 ° C.) using an aqueous solution in which 0% by weight was dissolved in water. After washing with water
The positive photoresist composition on the copper-clad laminate was peeled off by immersing it in a 5 wt% sodium hydroxide aqueous solution at 50 ° C. for 60 seconds. Further, the copper clad laminate was washed with water and dried with warm air. By observing a 50 μm line pattern on the copper clad laminate, the pattern reproducibility after etching is shown in FIG.
It evaluated based on b or c.

FIG. 1 is a sectional view of a pattern after etching (before peeling of the resist composition). a is an example with good pattern reproducibility. In b, the line pattern is thinner than a normal line, and in c, the line pattern is thicker than a normal line, and both b and c are examples of poor pattern reproducibility.

The results are shown in Table 1.

[0059]

[Table 1]

[Brief description of drawings]

FIG. 1 is a pattern cross-sectional view after etching.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-3-208054 (JP, A) JP-A-3-294861 (JP, A) JP-A-2-55359 (JP, A) JP-A-63- 210923 (JP, A) JP-A-62-35348 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (4)

(57) [Claims] 1. A wiring pattern on a copper clad laminate containing a photosensitizer containing cresol novolac resin and naphthoquinone diazide sulfonate as main components.
Met positive photoresist compositions for making over emissions
The cresol novolac resin has a weight average molecular weight (M
w) A positive photoresist composition which is 16000-75000 o-cresol novolac resin. 2. The positive photoresist composition according to claim 1, wherein the o-cresol novolac resin has a weight average molecular weight (Mw) of 16500 to 70,000. 3. The positive photoresist composition according to claim 1, wherein the weight average molecular weight (Mw) of the o-cresol novolac resin is 17,000 to 60,000. 4. The positive photoresist composition according to claim 1, 2 or 3, wherein the photosensitizer is contained in an amount of 10 to 50 parts by weight based on 100 parts by weight of the o-cresol novolac resin.