JP2001183824A - Positive photoresist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive photoresist having high sensitivity, high film remaining rate and high adhesion property, and particularly a photoresist which gives high adhesion property without deteriorating the sensitivity and film remaining characteristics. SOLUTION: In the positive photoresist composition containing m/p/o-cresol novolac resin, the content of o-cresol residues in the resin is 1 to 50% to the total of m/p/o-cresol residues. The weight average mol.wt. of the resin ranges 2,000 to 10,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoresist for microfabrication for manufacturing semiconductors and LCDs, and more specifically, for example, a wet etching process or a dry etching process using various acids, oxidizing agents, and reducing agents. Alternatively, the present invention relates to a positive photoresist composition suitable for plating.

[0002]

2. Description of the Related Art In recent years, displays and printer heads of industrial computers and the like have been increasing in size and miniaturization, and accordingly, materials such as metals, metal oxides or nitrides, and plastics have been developed. Precision has been required in the photo-etching process performed on the substrate. For example, required processing accuracy is 10μm
Therefore, a positive photoresist in this field is required to have not only excellent resolution but also a minimum amount of side etching during etching as much as possible.

[0003] However, the conventional positive type photoresist has a shortcoming that the amount of side etching in the photo-etching process is inevitably larger than a theoretical value because of insufficient acid resistance and adhesion to a substrate. There is. Therefore, for example, in the etching processing of a transparent conductive film such as a liquid crystal display body in which the base material is being miniaturized and enlarged, a positive photoresist having an extremely small amount of side etching and excellent acid resistance is developed. Is desired.

[0004]

Accordingly, the present invention has high sensitivity, high residual film ratio and high adhesiveness, and in particular, can provide high adhesiveness without deteriorating sensitivity and residual film characteristics. An object is to provide a positive photoresist.

[0005]

According to the present invention, m / p / o-
In a positive photoresist composition containing a cresol novolak resin, the content of o-cresol residues in the resin is 1 to 50% based on the total of m / p / o-cresol residues; The weight average molecular weight of the resin is
A composition characterized by having a molecular weight of 2,000 to 10,000 (1).

The present invention also relates to (2) a composition (1) in which the ratio of the peak area of cresol binuclear to the total positive peak area is 10% or less by a predetermined gel permeation chromatography method.

Further, the present invention relates to the composition (1) or (2), wherein the amount of side etch measured according to a predetermined adhesion evaluation method is 3.5 μm or less (3).

[0008]

DETAILED DESCRIPTION OF THE INVENTION The m / p / o-cresol novolak resin in the present invention is a copolymer of m-, p- and o-cresol with formaldehyde. here,
The content of the o-cresol residue in the resin is m
/ P / o-cresol residue, 1 to 50%, preferably 5 to 30%, more preferably 10 to 2%.
0%. The content of the p- and m-cresol residues is not particularly limited. However, when the content of the o-cresol residue is within the above preferable range and more preferable range, the content of m-cresol is 30 to 50%. It is preferable that the content of p-cresol is 40 to 60%. Further, the weight average molecular weight of the resin is 2,000 to 10,000, preferably 3,
000-5,000. This resin can be obtained according to a known method for producing a cresol novolak resin. The weight average molecular weight is determined according to the following method.

Method for analyzing weight average molecular weight and molecular weight distribution Measurement is carried out using gel permeation chromatography (GPC) at 40 ° C., at a flow rate of 1 ml / min, with a THF solvent and an RI detector. The column used was TSK gel manufactured by Toyo Soda Kogyo
G3000HXL, G2000HXL, and G2000HXL are connected one by one, and the weight average molecular weight is calculated using monodisperse polystyrene as a standard.

In the positive photoresist composition of the present invention, the ratio of the peak area of cresol binucleate to the total positive peak area by gel permeation chromatography is 10% or less, more preferably 1 to 1%.
0%, more preferably 5 to 10%. If the peak area ratio exceeds 10%, the softening point is significantly deteriorated, and the adhesion and heat resistance are reduced. Here, “cresol binuclear” refers to a monomer in which two m / p / o-cresol monomers are bonded via a methylene group,
Also included are those linked by oo, pp, etc.

The binuclear content can be controlled, for example, by fractionation or vacuum distillation. One example of the fractionation method is to dissolve the synthesized cresol novolak resin in a polar solvent (for example, methanol, ethanol or the like), and then put it in water or a water-polar solvent mixture to precipitate the resin component. In the vacuum distillation method, in the synthesis of a resin, for example, vacuum distillation at a temperature of 230 ° C. or higher (preferably 250 ° C. or higher) of 1.3 kPa or lower is performed.

As the photosensitizer contained in the composition according to the present invention, a photosensitizer containing a naphthoquinonediazidesulfonic acid ester as a main component is preferable, which comprises a naphthoquinonediazidosulfonic acid and a compound having a phenolic hydroxyl group. It can be easily produced by an esterification reaction according to a conventional method. here,
Examples of the compound having a phenolic hydroxyl group include, for example, novolak resins such as phenol novolak resins and cresol novolak resins, polyhydroxybenzophenones such as tetrahydroxybenzophenone and trihydroxybenzophenone, and further hydroxystyrene, alkyl gallate, and trihydroxybenzene monoethers. ,
2,2 ', 4,4'-tetrahydroxydiphenylmethane, 4,4'-dihydroxyphenylpropane, 4,
4'-dihydroxyphenylsulfone, 2,2'-dihydroxy-1,1-naphthylmethane, 2-hydroxyfluorene, 2-hydroxyphenanthrene, polyhydroxyanthraquinone, purprogalin and derivatives thereof,
Examples include phenyl-2,4,6-trihydroxybenzoic acid ester and trisphenol.

In the composition according to the present invention, the photosensitizer containing the naphthoquinonediazidesulfonic acid ester as a main component is preferably used in an amount of preferably 10 to 60 parts by weight, more preferably 100 to 60 parts by weight, based on 100 parts by weight of the cresol novolak resin. Is blended in a proportion of 20 to 50 parts by weight, more preferably 30 to 40 parts by weight.

The positive photoresist composition according to the present invention is preferably used in the form of a solution by dissolving the cresol novolak resin and a photosensitizer in a suitable solvent. Examples of such solvents include ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isoamyl ketone; monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether of ethylene glycol, ethylene glycol monoacetate, diethylene glycol or diethylene glycol monoacetate. , Polyhydric alcohol acids such as monophenyl ether and derivatives thereof; cyclic ethers such as dioxane; and ethyl acetate, butyl acetate, methyl lactate;
Esters such as ethyl lactate can be mentioned. These may be used alone, or two or more kinds may be used as a mixture, or an aromatic hydrocarbon such as xylene or toluene, or an alcohol-based solvent may be used in combination to improve the properties.

The positive photoresist composition according to the present invention may further contain, if desired, further compatible components such as an epoxy resin or an acrylic resin for improving the strength.
Polyvinyl ethers and various plasticizers for imparting plasticity, stabilizers for imparting stability, various activators for improving leveling properties, and various dyes for making the developed image more visible A commonly used material such as a pigment may be contained.

Using the positive photoresist composition of the present invention, the side etch amount is measured to be 3.5 μm or less, and optimally 2 μm or less, according to the following adhesion evaluation method. Thus, using the resist composition of the present invention,
High adhesion is obtained.

Adhesion evaluation method An ITO having a thickness of 1,000 mm was formed on a glass plate by the EB method, and the resist solution was uniformly dispersed to a thickness of 1.5 μm using a commercially available spin coater (manufactured by Dainippon Screen Co., Ltd.). After the application, it is dried on a hot plate at 110 ° C. for 90 seconds. Next, a mask aligner (PLA5, manufactured by CANON)
01F) through a test chart mask having a line and space of 10 μm for 2 seconds (illuminance: 12 mW / cm ² with an UV illuminometer UV-M20 UV35 sensor manufactured by ORC) and soft contact exposure to ultraviolet light. 38% by weight TMAH
Perform immersion rocking development at 25 ° C. for 90 seconds with an aqueous solution,
A 10 μm line and space are reproduced with the same width as the mask. A glass plate on which the photoresist was patterned was heated to 23 ° C. by dissolving 5 parts by weight of ferric chloride hexahydrate in a mixture of 45 parts by weight of pure hydrochloric acid and 45 parts by weight of pure water. Gently into the etching solution
After immersion etching treatment for 2 seconds, the glass plate is washed with water, the resist is stripped in a 3% by weight aqueous solution of NaOH at 50 ° C. for 60 seconds, then washed with pure water, and further dried with warm air to obtain a 10 μm line. Then, the side etch amount is measured.

The positive photoresist composition of the present invention comprises:
Typically, it can be used in a semiconductor manufacturing process such as an IC, a circuit substrate such as a liquid crystal and a thermal head, and other photofabrication processes.

Next, specific examples of the method for using the positive photoresist composition of the present invention will be described. First, the positive photoresist of the present invention is applied to a semiconductor wafer or a substrate of glass, ceramics, metal or the like by a spin coating method or a roller coating method to a thickness of 0.5 to 3 μm. afterwards,
Heating, drying, baking and developing a circuit pattern or the like by ultraviolet irradiation or the like through an exposure mask, and developing to obtain a positive image. Further, the substrate is processed in a pattern by etching using the positive image as a mask.

[0020]

EXAMPLE 1 40 g of m-cresol, 60 g of p-cresol, 11.1 g of o-cresol, 53 g of a 37% aqueous solution of formalin and 0.1 g of oxalic acid were charged into a three-necked flask and heated to 100 ° C. while stirring. The reaction was performed for the time shown in Table 1. Thereafter, the temperature was raised to 200 ° C. and the pressure was gradually reduced to 5 mmHg, and water, unreacted monomers, formaldehyde, oxalic acid and the like were distilled off. Next, the molten alkali-soluble novolak resin was returned to room temperature and collected. As a result, a novolak resin having an o-cresol content of 10% and a weight average molecular weight shown in Table 1 was obtained. Next, 100 parts by weight of the obtained cresol novolak resin and 2,2 of naphthoquinone-1,2-diazide-5-sulfonic acid were used.
After dissolving 20 parts by weight of 3,4-trihydroxybenzophenone ester in 300 parts by weight of propylene glycol monoether acetate, this was dissolved in a pore diameter of 0.2 μm.
The mixture was filtered using a membrane filter of No. 1 to prepare a photoresist composition. The binuclear content of this composition is:
It was 9.2% (in FIG. 1, the total area of the peaks in the part a was divided by the total area of the peaks in the parts a to c).

Example 2 A photoresist composition was prepared in the same manner as in Example 1 except that the amount of o-cresol was 25 g. The content of o-cresol in the novolak resin in this composition was 20%, and the content of binucleate was 9.4%.
(In FIG. 2, the total area of the peaks in part a was divided by the total area of the peaks in parts a to c).

Comparative Example 1 A photoresist composition was prepared in the same manner as in Example 1 except that o-cresol was not added. The binuclear content of this composition was 9.4% (in FIG. 3,
The total area of peaks in part a was divided by the total area of peaks in parts a to c).

Measurement result of sensitivity / film loss and evaluation of adhesion
Results In accordance with the following methods, for Examples 1 and 2 and Comparative Example 1, a measurement of the sensitivity / film loss and an evaluation test for adhesion were performed. The adhesion evaluation test method is as described above. Table 1 shows the results.

Sensitivity / residual film ratio measuring method A resist solution is uniformly coated on a silicon wafer using a spin coater (manufactured by Dainippon Screen Co., Ltd.).
It is dried on a hot plate at 110 ° C. for 90 seconds to obtain a resist film having a thickness of 1.5 μm. This wafer was placed in a G-line stepper (CANON FPA1550Mk III, NA =
0.48) and exposure using a test reticle. Next, a 2.38 wt% aqueous solution of TMAH was used at 25 ° C., 90
Perform immersion rocking development for 2 seconds to obtain Eth. Also, the residual film ratio of the unexposed portion (film thickness after development / initial film thickness × 100) is measured.

[0025]

[Table 1]

[Brief description of the drawings]

FIG. 1 shows a GPC chart of a resist composition of Example 1.

FIG. 2 shows a GPC chart of the resist composition of Example 2.

FIG. 3 shows a GPC chart of the resist composition of Comparative Example 1.

[Explanation of symbols] a Peak of binuclear body b, c Peak of non-binuclear body

Continuation of the front page (72) Inventor Yoshitaka Kamada 300 Kanayahara, Sakura-mura, Osamu-mura, Kitakanbara-gun, Niigata Prefecture F-term in the Samurai Plant of Shiprey Far East Co., Ltd. (reference) 2H025 AA01 AA02 AA04 AA09 AA14 AB14 AB16 AC01 AD03 BE00 BJ10 CB29 CB51 CB55 2H096 AA25 AA26 BA09 HA11 LA30 4J002 CC051 EQ036 EV246 FD206 GP03

Claims (3)

[Claims] 1. A positive photoresist composition containing a m / p / o-cresol novolak resin, wherein the content of the o-cresol residue in the resin is m / p / o-cresol novolak resin.
1 to 50% based on the total of p / o-cresol residues; the weight average molecular weight of the resin is from 2,000 to 10,000.
00. 2. The ratio of the peak area of cresol binuclear substance to the total positive peak area by a predetermined gel permeation chromatography method is 10% or less.
A composition as described. 3. The composition according to claim 1, wherein a side etch amount measured according to a predetermined adhesion evaluation method is 3.5 μm or less.