JPS599896B2 - Positive photoresist material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positive photoresist material suitable for forming fine patterns in the manufacturing process of integrated circuits and the like.

When irradiated with light (visible light, ultraviolet light) or radiation (electron beam, It is put to practical use as a mask material (for fine pattern formation, etc.) in the production of products, an information recording material, etc.

For example, a positive photoresist material in which a naphthoquinonediazide sulfonic acid derivative is introduced into the molecule of a reaction product of phenol and formalin (novolac resin) as a main photosensitive component is known as a pattern forming material.
However, since this positive photoresist material has poor coating properties and coating properties, it is necessary to handle it carefully after the photoresist film is formed on the surface of a semiconductor wafer, for example. Therefore, during exposure, non-uniform contact pressure between the photoresist film provided on the semiconductor wafer and the hard mask is likely to occur, resulting in many inconveniences in terms of pattern accuracy and yield in the phosphorography process. Therefore, it is an object of the present invention to provide a positive photoresist material that has good coating properties and physical properties of the formed coating film, and is capable of forming a highly accurate positive pattern with a high yield.

To explain the present invention in detail below, the present invention relates to a naphthoquinonediazide sulfone residue in the molecule of a phenolic polymer consisting of a repeating unit represented by the general formula: This is a positive type photoresist material characterized by incorporating.

The positive photoresist material of the present invention can be easily obtained as follows.

That is, phenol and an alkyl dialdehyde compound or phenol, thiophene, and formalin are used as reaction components, and a condensation dehydration reaction is performed using an acid catalyst or an alkali catalyst, or after this condensation dehydration reaction, a hydrogenation metal catalyst such as Raney nickel is used to further hydrodesulfurize. By doing this, a phenolic polymer represented by the above general formula is first obtained. Next, a naphthoquinone diazide sulfonic acid derivative, such as 1,2 naphthoquinone 2-diazide-5-sulfonyl chloride, is added to this phenolic polymer, and if necessary, a basic dehydration catalyst such as pyridine or sodium carbonate is added and reacted by stirring. A phenolic polymer having a naphthoquinonediazide sulfone residue introduced into the molecule is obtained. The positive photoresist material made of a phenolic polymer with a naphthoquinonediazide sulfone residue introduced into the molecule obtained as described above is soluble in organic solvents such as toluene, chloroform, acetre, and cellosolve acetate, and is easily dissolved in solution. When applied to a predetermined substrate surface, it can exhibit good coating properties and form a coating film with excellent adhesion.

For example, when the photoresist material solution was applied to a glass plate with a smooth surface and dried under reduced pressure and heat, a coating film was formed that had no cracks or pinholes and strongly adhered to the glass plate. Furthermore, the coating film exhibits high sensitivity to ultraviolet light, visible light, electron beams, X-rays, gamma rays, etc., and a positive pattern can be easily obtained. These effects include, for example, the presence of nutquinone diazide in the molecules of novolak resin. In the case of conventionally known positive resist materials that incorporate dosulfone residues, there are many problems such as difficulty in forming a uniform coating, formation of pinholes and cracks, and easy peeling of the coating. This is a significant difference, although it is recognized as an inconvenience. Thus, the positive photoresist material according to the present invention has good coating properties and adhesion, making it easy to handle, exhibiting high sensitivity to light and radiation, and being able to form fine patterns with high precision. It can be said that it is suitable for use as a mask material for integrated circuits or as an information recording material using light or the like. Next, examples of the present invention will be described.

Example 1 94 f of phenol, 84 f of chinophene, 200 ml of acetic acid, and 200 ml of 35% formalin solution were placed in a 11 Erlenmeyer flask, mixed and kept at 70-80°C, and 15 ml of 0.5N sulfuric acid was added dropwise. A time polycondensation reaction was carried out.

After the above reaction, the reaction solution was poured into 31 water, the oil layer was separated, and 100 d of ethyl ether was added to the separated oil layer.
was added, and the reaction product polymer was extracted with a 20% aqueous sodium hydroxide solution. Thereafter, the above extract (polymer) was washed with 200 d of ethyl ether and further neutralized with 1N hydrochloric acid to obtain a white viscous polymer with a thiophene odor. The thus obtained polymer was dissolved in 100 ml of a 30% aqueous sodium hydroxide solution, heated to 40 to 50°C, W-7 type Raney Nickel 5V was gradually added, and vigorously stirred for 8 hours to perform hydrodesulfurization. , remove the catalyst,
Further, by acidifying with 1N hydrochloric acid, a white polymer with a phenol odor was precipitated and separated. This white polymer was soluble in celeryl, tetrahydrofuran, methyl ethyl ketone, ethanol, etc. The above phenolic polymer 22t and 1,2 naphthoquinone 2-diazide
54 t of 5-sulfonyl chloride was added to 450 f of dioxane and kept at 40° C. with vigorous stirring, and then a 10% aqueous sodium carbonate solution at 200 V was added and allowed to react in a dark place for 2 hours.

After that, insoluble materials were removed from the reaction system, and the solution was
The precipitate obtained by dropping into 0 ml of ice was collected, washed with 100 ml of methyl alcohol, and dried at a temperature below 50°C to obtain a phenolic polymer with naphthoquinonediazide sulfone residues introduced ( A positive photoresist material) was obtained. One ton of the positive photoresist material thus obtained was dissolved in a mixed solution of acetic acid-n-butyl-xylene-cellosolve acetate (mixing ratio 9:10:81) and coated onto a silicon wafer to a thickness of about 1 μm by spin coating. After, 60
Pre-baking was performed at .degree. C. for 20 minutes to remove the solvent, and a photoresist film was formed.

Claims (1)

[Claims] 1. Naphthoquinonediazide sulfone in the molecule of a phenolic polymer consisting of repeating units represented by the general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (in the formula, n represents a number of 1 or more) A positive photoresist material characterized by introducing a residue.