JPH03208054A - Novel positive type photoresist composition - Google Patents

Abstract

PURPOSE:To decrease the side etching quantity of the resist by compounding a specific cresol novolak resin with the compsn. CONSTITUTION:The cresol novolak resin (A) and a photosensitizer essentially consisting of naphthoquinone diazide sulfonate are compounded with this compsn. The resin which is condensed by using a cresol mixture composed of 60 to 95wt.% o-cresol and 40 to 5wt.% p-cresol, is adjusted in the ratio Mw/Mn of 5,000 to 15,000 weight average mol. wt. (Mw) and number average mol. wt. (Mn) to a 2.0 to 6.0 range and has <=5wt.% content of the unreacted monomer is used for the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel positive photoresist composition, and more particularly, to wet etching treatment and dry etching treatment using various acids, oxidizing agents, reducing agents, etc. The present invention relates to a positive-type photoresist assembly suitable for use.

Conventional technology Recently, displays for industrial computers, printer heads, etc. have become larger and smaller, and as a result, materials such as metals, metal oxides, nitrides, and plastics have become smaller and smaller. Precision is now required in the photo-etching process performed in the manufacturing process. For example, the required processing accuracy ranges from about 10 μm to about 5 μm, and for this reason, positive photoresists in this field are required not only to have excellent resolution but also to reduce the amount of side etching as much as possible during etching.

By the way, normal positive photoresists are protected from anolekali-soluble nopolac resin and photodecomposition, that is, a photosensitizer, and naphthoquinonediazide sulfonic acid ester is used as the photosensitizer. (U.S. Patent No. 3,402,
044 specification). Moreover, various kinds of esters have been disclosed so far (U.S. Patent No. 3,0
No. 46,118, No. 3,106,465, No. 3,148,983).

On the other hand, regarding the alkali-soluble nopolanok resin, for example, the use of phenol-formaldehyde nopolanok resin is disclosed (U.S. Pat. No. 3,402.044), and examples of the use of talesol nopolanok resin are disclosed. It has been reported [“Electrochemistry and Industrial Physical Chemistry” No. 48]
Volume, page 584 (1980)].

Furthermore, it is also known that a highly sensitive positive type photoresist can be obtained by appropriately selecting the blending ratio of cresol isomers during production of Talesol nopolac resin.

However, in the conventional positive photoresist,
Due to the lack of acid resistance and adhesion to the base material, there is a drawback that the amount of side etching during photolithography inevitably becomes larger than the theoretical value. Therefore, for example, in the etching process of transparent conductive films such as liquid crystal displays where substrates are currently becoming finer and larger, it is desirable to develop a positive photoresist that has an extremely small amount of side etching and has excellent acid resistance. It is rare.

SUMMARY OF THE INVENTION The present invention overcomes the drawbacks of conventional positive type photoresists and minimizes the amount of side etching of photoresists during photoetching of various materials such as metals and metal oxide films. The purpose of this invention is to provide a positive-working photoresist composition that is moisturizing.

Means for Solving the Problems As a result of intensive research to develop a positive type photoresist composition having the above-mentioned preferable properties, the present inventors discovered a mixture of 0-cresol and p-cresol in a specific proportion. It was discovered that the purpose could be achieved by using a cresol nopolac resin obtained from cresol and having a specific molecular weight, molecular weight distribution, and unreacted monomer content, and based on this knowledge, this book was developed. The invention was completed.

That is, the present invention provides a positive type photoresist composition comprising a Talesol Nopolak resin and a photosensitizer mainly containing naph-1-quinonediazide sulfonic acid ester, in which the Talesol Nopolak resin is a 0- Cresol 60-95% by weight and p-cresol 4
It is obtained from mixed cresol with 0 to 5% by weight, and has a weight average molecular weight (Mw) of 5000 to 15000.
, the ratio My/Mn of weight average molecular weight (Mw) to number average molecular weight (Mn) was in the range of 2.0 to 6.0, and the content of unreacted monomer was 5% by weight or less. The object of the present invention is to provide a positive type photoresist assembly characterized by the following.

The present invention will be explained in detail below.

In the composition of the present invention, the Talesol nopolac resin used is one obtained from a mixed cresol of 60 to 95% by weight of 0-cresol and 40 to 5% by weight of p-cresol. The content of the 0-cresol is 60% by weight
If the amount is less than 95% by weight, the development stability of the resultant composite material is improved, but the resist adhesion is poor, and if it exceeds 95% by weight, the development stability tends to deteriorate. Also,
The Talesol Noporank resin has a weight average molecular weight (Mw
) is in the range of 5,000 to 15,000, and the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), which is an index of molecular weight distribution, is in the range of 2.0 to 6.0, It is necessary that the content of unreacted monomers be 5% by weight or less.

If the weight average molecular weight (Mw) is less than 5,000, the resulting composition will have improved adhesion but will have insufficient acid resistance, and if it exceeds 15,000, sensitivity will decrease or development residues will be formed. There is a tendency to

In addition, weight average molecular weight (Mty) and number average molecular weight (Mn
) If the ratio My/Mn is less than 2.0, the composition will have high resolving power but will have poor adhesion; if it exceeds 6.0, the resolving power will decrease or the development stability and acid resistance will deteriorate. There is a tendency for things to get worse. Furthermore, if the content of unreacted monomer exceeds 5% by weight, the acid resistance of the resulting composition will be significantly reduced. This compound can be easily produced by esterifying Na7l.quinone./'azidosulfonic acid and a compound having a phenolic hydroxyl group according to a conventional method. can.

Examples of the compound having a phenolic hydroxyl group include nopolac resins such as phenol novolak resin and Talezol nopolanc resin, polyhydroxybenzophenones such as tetrahydroxybenzophenone and trihydroxybenzophenone, and further hydroquinone styrene and gallic acid. Alkyl, trihydroquine benzene heptanoethers, 2.2'. 4.4'-tetrahydroxydiphenylmethane, 4.4'-dihydroxyphenylbroban, 44
'-dihydroxydi7enyl sulfone, 2,2'-cyhydroxy-1,1-naphthylmethane, 2-hydroquinefluorene, 2-hydroxyphenanthrene, polyhydroxyanthraquinone, purprogalin and its derivatives,
Examples include phenyl-2.4.6-}rehydroxybenzoic acid ester and trisphenol.

In the composition of the present invention, the photosensitizer mainly containing the naphthoquinone diacytosulfonic acid ester is used in an amount of IO per 100 parts by weight of Talesol Nopolac resin.
It is preferable to mix it in a proportion of 60 parts by weight. If the amount is less than 10 parts by weight, the sensitivity will increase, but there is a risk of film loss during development and a decline in the profile of the resist pattern. The problem arises.

The positive photoresist composition of the present invention is preferably used in the form of a solution by dissolving the Talesol Nopolac resin and the photosensitizer in a suitable solvent. Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone; monomethyl ether, monoethyl ether, monobrobyl ether of ethylene glycol, ethylene glycol monoacetate, diethylene glycol or diethylene glycol monoacetate; Examples include polyhydric alcohols and derivatives thereof such as monobutyl ether and monophenyl ether; cyclic ethers such as dioxane; and esters such as ethyl acetate, butyl acetate, methyl lactate, and ethyl lactate. These may be used alone or in combination of two or more, and
In order to improve the properties, aromatic hydrocarbons such as quinolene and toluene, alcoholic solvents, etc. may be used in combination.

Positive type photoresist of the present invention! 1. If desired, some materials may be added with roughly compatible additives, such as epoxy resins and acrylic resins to improve strength, polyvinyl ethers and various plasticizers to impart plasticity, and stabilizers. It can contain commonly used substances such as stabilizers to impart properties, various activators to improve leveling properties, and various dyes and pigments to make developed images more visible. .

Next, a preferred example of the method of using the composition of the present invention will be explained. A solution prepared by dissolving the above-mentioned Talesol Nopolac resin, a photosensitizer, and various additive components used as desired in an appropriate solvent is applied onto a plate using a roll coater, dried, and exposed to light. After the layer is formed, it is exposed to light through a required mask using a mirror projection exposure device or the like, and is then exposed to a tetramethylammonium hydroxide or choline aqueous solution with a concentration of 1.5 to 5% by weight, or 0.3 to 5% by weight. 1
．． By developing with a developer such as sodium hydroxide or potassium hydroxide aqueous solution with a concentration of 5M amount %, the portions made solubilized by exposure are selectively dissolved and removed to form a resist pattern that is faithful to the mask pattern. . Next, the parts of the ITO film exposed by the resist pattern are removed using an appropriate etching solution containing hydrochloric acid, sulfuric acid, nitric acid, ferric chloride, etc. as the main ingredients, and then the resist is peeled off using an alkali or solvent. By doing so, it is possible to obtain an ITO film transparent conductive wiring board that is faithful to the resist pattern.

Effects of the Invention The positive type photoresist composition of the present invention is a novolak resin obtained from a mixed cresol of 0-cresol and p-cresol in a predetermined ratio and having a specific molecular weight, molecular weight distribution, and unreacted monomer content. and a photocene/tizer whose main component is naphthoquinonediazide sulfonic acid ester, and the resist 1 pattern obtained by exposure and development processing, or various acids, oxidizing agents, reducing agents, etc. It has strong resistance to wet and dry etching using metals and excellent adhesion to base materials such as metals, metal oxides, and nitrides, making it suitable for photoetching of these base materials. used.

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.

Example 1 O-cresol and p-cresol in a weight ratio of 90:1O
Talesol noporanok resin 10 obtained by mixing in the ratio of
0 parts by weight (Mwl.0000, Mw/Mn4.O,
unreacted monomer content 1% by weight) and naphthoquinone-1,
After dissolving 2.3.4-trihydroquine benzophenone ester of 2-diazide-5-sulfonic acid in 300% of ethylene glycol monoethyl ether acetate, this was added to a membrane with a pore size of 0.2 μm. A photoresist composition was prepared by filtration using a filter. This resist composition is formed into an IT○ with a thickness of IOOOA on a glass plate by the EB method, washed with a neutral detergent and purified water, dried, and then irradiated with ultraviolet rays to decompose and remove organic matter on the surface. Apply a commercially available roll coater (manufactured by Thermatronics Trading Co., Ltd.) onto the pretreated glass plate.
After applying it uniformly to a thickness of 1.5 μm using
0'? 1" was dried on a hot plate for 180 seconds. Then, a mirror projection exposure device (manufactured by ORC,
HMW-661 B) was used for 3 seconds (OR) through a test chart mask with 5 μm lines and spaces.
After soft contact exposure to ultraviolet light (illuminance 17 mW/cm2) using an ultraviolet light meter UV-MO2 UV35 sensor (manufactured by Company C), immersion and rocking development was performed at 25°C for 145 seconds in a 1.0 wt% KOH aqueous solution. The lines and spaces are reproduced with the same width as the mask.

The glass plate patterned with this Hole resist,
A solution of 10 parts by weight of ferric chloride hexahydrate in a mixture of 45 parts by weight of 35% pure hydrochloric acid and 45 parts by weight of pure water was gently poured into an etching solution heated to 5,000 ℃.
After performing a second immersion etching process, the glass plate was washed with water, and the resist was removed for 60 seconds in a 3% by weight NaOH solution at 50°C, then washed with pure water, and further dried with hot air to form a 5 μm line. When the side etching amount was measured, it was found to be 1.5 μm, which was a good result.

For comparison, when a commercially available OFPR-800C manufactured by Tokyo Ohka Kogyo Co., Ltd. made of m-, p-talesol nopolasoc resin was used, the amount of side etching was 3.
It was 0pm.

Example 2 60% by weight of 0-cresol and 40% by weight of p-cresol
Talesol novolac resin (Mwiiooo, li
A photoresist composite was prepared in the same manner as in Example 1 except that w/Mn 5.0 and unreacted monomer content 1% by weight were used. A 1,500-layer chromium film was deposited on Motomura and patterned in the same manner as in Example 1, and then ceric ammonium nitrate and 50% pure perchloric acid were applied.
Etching was performed using an etching solution dissolved in pure water at a ratio of 12% by weight and 7% by weight, respectively, by immersion at 40°C for 13 minutes, and then the resist was removed in the same manner as in Example 1. Ta.

The side etch amount in this case is 0.5 μm, and 5 μm
The resist line was a straight chrome line of 4.5 μm.

Example 3 100 parts by weight of Talezol Nopolasoc resin obtained in Example 1 and 15 parts by weight of gallic acid probyl ester of naphthoquinone-1,2-diazide-5-sulfonic acid were added to 300 parts by weight of ethyl lactate. Using the photoresist composition obtained by melting, buttering was performed on a glass plate on which an aluminum film had been vapor-deposited in the same manner as in Example 1, and further post-baked on a real plate at 120°C for 3 minutes. and then add 85% pure phosphoric acid and 95% pure phosphoric acid and 70% pure phosphoric acid.
% of nitric acid and 5% by weight of etching solution containing 40% by weight of nitric acid.
After etching the vapor-deposited aluminum by dipping at 70°C for 1 minute, the resist was removed using Stripper 10 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 70°C, and after washing with acetone, the aluminum was etched. Wash with water.

In this case, the side etch amount is 'I. ．． Opm or less, and good results were obtained without any wobbling.

Example 4 Using the photoresist composition of Example 1, a resist coater (manufactured by Mikasa Co., Ltd., 1}1-365) was applied onto a silicon wafer.
Apply the coating uniformly to a thickness of 1.5 μm using a mold).
0'C! It was dried on a photoplate for 180 seconds. Next, the film was exposed to light using a mirror projection exposure device in the same manner as in Example 1, and developed, followed by post-baking at 140° C. for 5 minutes using a real plate.

Next, the patterned silicon wafer was etched using a plasma etching device OPM-EM-600 [manufactured by Tokyo Ohka Kogyo Co., Ltd.] by introducing carbon tetrafluoride gas containing 5% by volume of oxygen as a gas. - When dry etching was performed using a 100W dry etching power, there was no change in quality of the resist and good results were obtained.

Claims (1)

[Claims] 1. A positive photoresist composition comprising a cresol novolak resin and a photosensitizer containing a naphthoquinonediazide sulfonic acid ester as a main component,
As the cresol novolac resin, o-cresol 6
It is obtained from a mixed cresol of 0 to 95% by weight and 40 to 5% by weight of p-cresol, and has a weight average molecular weight (Mw) of 5000 to 15000 and a weight average molecular weight (
The ratio Mw/Mn of Mw) and number average molecular weight (Mn) is 2.
1. A positive photoresist composition characterized in that the content of unreacted monomers is in the range of 0 to 6.0 and has an unreacted monomer content of 5% by weight or less.