JPH03208055A - Positive type photoresist composition - Google Patents

Abstract

PURPOSE:To improve the etching property, plating property, etc., of the resist by compounding a specific alkali-soluble novolak resin with the compsn. CONSTITUTION:This compd. is compounded with the alkali-soluble novolak resin (A) and a photosensitizer essentially consisting of naphthoquinine diazide sulfonate. The resin contg. 20 to 80wt.% o-cresol novolak resin (B) having a weight average mol. wt. (Mw) ranging 800 to 1,500 and the ratio MW/Mn between the mol. wt. Mw and number average mol. wt. (Mn) ranging 1.5 to 3.0 is used as the component A. The alkali-soluble novolak resin having the mol. wt. Mw within a 5,000 to 15,000 range is preferably incorporated as the novolak resin exclusive of the component B into the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to positive photoresist compositions, more specifically wet etching treatments, dry etching treatments using various acids, oxidizing agents, reducing agents, etc., or plating treatments. The present invention relates to a positive photoresist composition suitable for various purposes.

Conventional technology In recent years, displays for industrial computers, printer heads, etc. have become larger and finer. Precision is now required in the photo-etching and polishing processes used in manufacturing. For example, the required processing accuracy is 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, a normal positive photoresist consists of an alkali-soluble novolak resin and a photolytic sensitizer, and naphthoquinonediazide sulfonic acid ester is used as the photosensitizer ( U.S. Patent No. 3.402.044
8). In addition, regarding such esters,
Various disclosures have been made so far (U.S. Patent No. 3.046,
No. 118, No. 3,106,465, No. 3,148,983).

On the other hand, regarding alkali-soluble novolak resins, for example, the use of phenol-formaldehyde novolak resin has been disclosed (U.S. Pat. No. 3,402,044), and examples of the use of Talezol novolak resin have been reported. [“Electrochemistry and Industrial Physical Chemistry” No. 48]
Volume, page 584 (1980 PM)].

Furthermore, it is also known that a highly sensitive positive photoresist can be obtained by appropriately selecting the blending ratio of cresol isomers when producing a cresol novolac resin.

However, in conventional positive photoresists,
Since the acid resistance and adhesion to the base material are poor, the amount of side etch during etching and the plating resistance are no longer sufficient to fully satisfy the recent demands for miniaturization. Therefore, there is a strong demand for the development of a positive photoresist with excellent etching properties, plating properties, etc. that can accommodate upsizing and miniaturization.

Problems to be Solved by the Invention The present invention overcomes the drawbacks of the conventional positive photoresist as described above, in order to cope with the increasing size and miniaturization of displays such as industrial computers and printer heads. The purpose of this invention is to provide a positive type photoresist composition with excellent etching properties and adhesion properties.

Means for Solving the Problems As a result of intensive research to develop a positive photoresist composition with excellent etching and adhesion properties, the present inventors have developed an alkali-soluble noporak resin with a specific molecular weight and molecular weight distribution. It has been discovered that the above object can be achieved by using an O-cresol novolak resin containing a predetermined ratio of O-cresol novolac resin having the following properties, and based on this knowledge, the present invention has been completed.

That is, the present invention provides a positive photoresist composition containing an alkali-soluble novolac resin and a photosensitizer mainly containing a naphthoquinonediazide sulfonic acid ester, in which the alkali-soluble novolac resin has a weight average molecular weight (Mw ) is 800 ~ 1500
, the ratio Mw/Mn of weight average molecular weight (Mw) to number average molecular weight (Mn) is 1.5 to 3. The present invention provides a positive photoresist composition containing 20 to 80% by weight of an O-talesol novolac resin in the range of O.

The present invention will be explained in detail below.

In the composition of the present invention, the alkali-soluble novolac resin has a weight average molecular weight (Mw) of 800 to 1500.
, preferably in the range of 900 to 1,400, and the ratio My/Mn of weight average molecular weight (My) to number average molecular weight (Mn), which is an index of molecular weight distribution, is 1.5 to 3.0, preferably 1. 20 to 80% by weight of o-cresol novolak resin in the range of 8 to 2.5, preferably 40 to 70% by weight.
It is necessary to use those containing in weight percent.

If the content of the 0-cresol novolak resin in the alkali-soluble novolak resin is less than 20% by weight, the resulting composition may have improved acid resistance and development stability, but the adhesion to the substrate may deteriorate; 80% by weight
If it exceeds 20%, there is a tendency for development stability to deteriorate. In addition, the weight average molecular weight of the o-cresol novolak resin (
If My) is less than 800, the resulting composition will have improved adhesion to the substrate, but will have insufficient acid resistance, and if it exceeds 1500, the adhesion to the substrate will tend to decrease. Furthermore, if the ratio My/Mn of the weight average molecular weight (Mw) to number average molecular weight (Mn) of the o-cresol novolak resin is less than 1.5, the resulting composition has high resolution but may have poor adhesion. If it exceeds 3.0, resolution tends to decrease and development stability and acid resistance tend to deteriorate.

In addition, unreacted 0 in this o-cresol novolac resin
- The cresol content is preferably 5% by weight or less; if this amount exceeds 5% by weight, the acid resistance of the resulting composition will be significantly reduced, which is not preferred. In order to remove this unreacted 0-cresol from the novolac resin, for example, a method may be used in which 0-cresol is condensed with formaldehyde, etc., and then distilled, or the resin after condensation is mixed with a good solvent and a poor solvent. A method of fractionation and purification may also be used.

The alkali-soluble novolak resin used in the composition of the present invention contains other alkali-soluble novolak resins in addition to the o-cresol novolak resin.
) is preferably in the range of 5,000 to 15,000. Other alkali-soluble novolak resins may be selected from alkylphenols such as m-cresol, p-cresol, 3.5-xylenol, 2,4-xylenol, 2,5-xylenol, and 2,6-xylenol. Examples include those obtained from at least one species. The content of unreacted alkylphenol in this novolac resin is also preferably 5% by weight or less for the same reason as mentioned above.

The photosensitizer used in the composition of the present invention is one containing naphthoquinonediazide sulfonic acid ester as a main component, and this photosensitizer is used by esterifying naphthoquinonediazide 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 7-enol novolac resin and Talezol novolak resin, polyhydroxybenzo-7-enone such as tetrahydroxybenzo-7-enone and trihydroxybenzo-7-enone, and further hydroxystyrene and gallic acid. Alkyl acid, trihydroxybenzene heptanoethers, 2.2'. 4.4'-tetrahydroxydiphenylmethane, 4.4'-dihydroxyphenylpropane, 4.
4'-dihydroxydiphenylsulfone, 2,2'-dihydroxy-1.1-na7tinolemethane, 2-hydroxyphnoleolene, 2-hydroxyphenanthrene, polyhydroxyanthraquinone, purbrogalin and its derivatives, phenyl-2.4.6- Examples include trihydroxybenzoic acid ester and trisphenol.

In the composition of the present invention, the photosensitizer containing the naphthoquinonediazide sulfonic acid ester as a main component is
It is preferable to mix it in a proportion of 10 to 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 prepared by dissolving the novolac resin and the photosensitizer in a suitable solvent.
Preferably, it is used in the form of a solution.

Such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone; monomethyl ether, monoethyl ether, monoglobyl ether, monobutyl ether of ethylene glycol, ethylene glycol monoacetate, diethylene glycol or diethylene glycol heptanoacetate. , polyhydric alkyls such as 7-enyl ether and derivatives thereof; cyclic ethers such as dioxane; and esters such as ethyl acetate, butyl acetate, methyl lactate, ethyl lactate. can.

These may be used alone or in combination of two or more, and aromatic hydrocarbons such as xylene and toluene, alcoholic solvents, etc. may be used in combination to improve properties.

The positive photoresist composition of the present invention may optionally include:
Additives that are compatible with the grain, such as epoxy resins and acrylic resins to improve strength, polyvinyl ethers and various plasticizers to impart plasticity, stabilizers to impart stability, and improve leveling properties. It is possible to contain various activators for this purpose, or various dyes and pigments for making the developed image 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 alkali-soluble novolak resin, photosensitizer, and various additives used as desired in an appropriate solvent is applied onto the plate using a roll coater, and then dried. After shaping the photosensitive layer, it is exposed to light through a required mask using a mirror projection exposure device or the like.
Next, this is mixed with 1.5 to 5% by weight of tetramethylammonium hydroxide or choline aqueous solution, or 0.3 to 1% by weight of tetramethylammonium hydroxide or choline solution.
．． By developing with a developer such as 5% by weight sodium hydroxide or potassium hydroxide aqueous solution, the portions made solubilized by exposure are selectively dissolved and removed, forming 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 a transparent conductive wiring board made of an IT◯ film that is faithful to the resist pattern.

Effects of the Invention The positive photoresist composition of the present invention comprises an alkali-soluble novolak resin containing an O-talesol novolak resin having a specific molecular weight and molecular weight distribution in a predetermined ratio;
It contains a photosensitizer mainly composed of naphthoquinonediazide sulfonic acid ester, and the resist pattern obtained by exposure and development is wet etched using various acids, oxidizing agents, reducing agents, etc. It has strong resistance to processing, dry etching, or plating, and has excellent adhesion to substrates such as metals, metal oxides, nitrides, and plastics, making it suitable for photoetching of these substrates. Suitable for processing.

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 m-cresol and p-cresol in a weight ratio of 90:IO
40 weight of high molecular weight talesol novolac resin (Mw 10000, unreacted content 0.5% by weight) obtained by adding trioxane and condensing it in the presence of a sulfuric acid catalyst, followed by distillation. and a low molecular weight o-cresol novolac resin (My1250, Mw/Mn2.0) obtained by the same method using o-cresol.
40 parts by weight and na7toquinone-1,2-diazide-5
-2.3.4- of sulfonic acid }Ryhydroxybenzophenone ester 2 0R amount Mt-, -Z tyrene glycol monoethyl ether acetate 300! ! After dissolving in a certain amount, this was filtered using a membrane filter with a pore size of 0.2 μm to prepare a photoresist composition.

Next, an IT layer with a thickness of 0.1 μm was placed on a glass plate using the EB method.
The photoresist composition was coated with a commercially available roll coater (
The coating was applied uniformly to a thickness of 1.5 .mu.m using the Thermatronics Buyi Co., Ltd.), and then dried on a hot plate at 90.degree. C. for 180 seconds. Next, using a mirror projection exposure device (ORC company fi, HMW-661B), a test chart mask with lines and spaces of 5prrr was used for 3 seconds (ORC company, ultraviolet illuminometer U).
V-MO2 UV35 sensor with illuminance 17mW/
cm”) After UV soft contact exposure, 1.0
Immersion and rocking development was performed at 25° C. for 145 seconds using a wt % KOH aqueous solution to reproduce 5 μm lines and spaces with the same width as the mask.

The glass plate patterned with this photoresist was prepared by dissolving 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.
Warm it to 'O'; Gently put it into the etching solution, immerse it for 180 seconds to perform etching treatment, wash the glass plate with water, perform resist peeling treatment for 60 seconds in a 3% by weight aqueous solution of NaOH at 50°C, and then use pure water. By washing and drying with hot air, a good result with a side etching amount of 1.0 μm was obtained for a 5 μ1 line.

For comparison, when a commercially available OFPR-800 [manufactured by Tokyo Ohka Kogyo Co., Ltd.] made of m-, p-talesol novolac resin was used, the side etch amount was 3.
It was 0 μm.

Example 2 60% by weight m-cresol and 40% by weight p-cresol
A resin obtained by fractionating and refining Talesol novolac resin obtained in the same manner as in Example I using cresol mixed with methanol-water system (Mw 7500, unreacted content 2.0% by weight) and a resin obtained in Example 1. A photoresist composition was prepared in the same manner as in Example 1 by mixing a low molecular weight o-cresol novolak resin at a weight ratio of 70:30.

Next, using this photoresist, 0.15
Example I
After buttering in the same way as above, add 1000g of pure water.
The vapor deposited chromium was etched using an etching solution in which ceric ammonium nitrate and perchloric acid with a purity of 50% were dissolved at a ratio of 12% by weight and 711% by weight, respectively, by an immersion method at 40°C for 3 minutes. Then, the resist was removed in the same manner as in Example 1.

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 60 parts by weight of the high molecular weight cresol novolac resin obtained in Example 1, 40 parts by weight of the low molecular weight 0-cresol novolac resin, and naphthoquinone-1,2-diazide-5
- After preparing a photoresist composition by dissolving 15 parts by weight of gallic acid probyl ester of sulfonic acid in 300 parts by weight of ethyl lactate, this composition was used to coat a glass plate with an aluminum coating provided by vapor deposition. , patterned in the same manner as in Example 1, further host-baked on a hot plate at 120°C for 3 minutes, and then using this as a mask, 85% pure phosphoric acid and 95% pure phosphoric acid and 70% pure
In an etching solution containing 51% of nitric acid, at 40°C.
The vapor-deposited aluminum film was etched by dipping for 1 minute, then the resist was stripped at 70'C using a stripper IO (manufactured by Tokyo Ohka Kogyo Co., Ltd.), and after washing with acetone, the aluminum film was etched. Washed with water.

In this case, the side etching amount was 1.0 μm, and good results were obtained without any wobbling.

Example 4 The photoresist composition of Example 1 was uniformly coated on a silicon wafer to a thickness of 1.5 μm using a resist footer (manufactured by Mikasa, Model IH-363), and then heated at 90°C.
It was dried on a hot plate for 180 seconds. Next, the film was exposed and developed using a mirror projection exposure apparatus in the same manner as in Example 1, and then post-baked at 140° C. for 5 minutes using a hot plate.

Next, the patterned silicon wafer was subjected to plasma etching equipment ○PM-EM-600 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), and carbon tetra7ide gas containing 5% by volume of oxygen gas was introduced as a gas. Etching power 1
When dry etching was performed at 00W, good results were obtained with no deterioration of the resist.

Example 5 In Example 1, m-cresol and p-cresol were mixed at a weight ratio of 70:30 as a high molecular weight talesol novolanc resin, trioxane was added thereto, and the mixture was mixed in the presence of a sulfuric acid catalyst. After condensation, a cresol novolac resin (Mw 9000
A photoresist composition was prepared in the same manner as in Example 1, except that 0.5 wt. , IH-363 model) to a blade thickness of 2.5 μm, and then dried on a hot plate at 110° C. for 300 seconds. Next, the film was exposed and developed using a mirror projection exposure apparatus in the same manner as in Example 1, and then post-baked at 120° C. for 30 minutes using a hot air dryer.

Next, the patterned wafer was placed in a neutral cyan gold plating solution (Temperex 401) at 70°C.
．． When plating was performed at a current density of OA/dm'' (gold thickness: 2.0 μm), good results were obtained with no deterioration of the resist or seepage of the plating solution.

For comparison, a certain commercially available OFPR-800 (Tokyo Ohka Kogyo Co., Ltd.) made from m-, p-cresol novolac resin was used.
Co., Ltd.], staining and peeling occurred.

Claims (1)

[Scope of Claims] 1. In a positive photoresist composition comprising an alkali-soluble novolac resin and a photosensitizer containing a naphthoquinonediazide sulfonic acid ester as a main component, the alkali-soluble novolak resin has a weight average molecular weight (Mw) is 800-1500, weight average molecular weight (
The ratio Mw/Mn of Mw) and number average molecular weight (Mn) is 1.
A positive photoresist composition containing 20 to 80% by weight of an o-cresol novolac resin in the range of 5 to 3.0% by weight. 2. The positive photoresist according to claim 1, wherein the alkali-soluble novolak resin contains an alkali-soluble novolak resin having a weight average molecular weight (Mw) in the range of 5,000 to 15,000 as a novolak resin other than o-cresol novolak resin. Composition.