JPS6352371B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel positive photoresist compositions. More specifically, the present invention uses (a) a polycondensate of bis-salicylaldehyde and o-phenylenediamine, and (b) o-benzoquinonediazide sulfonic acid ester or o-naphthoquinonediazide sulfonic acid ester as composition components. The present invention relates to a novel positive photoresist composition containing as a component of the composition.

In recent years, with the increasing density of ICs, it has been desired to improve the resolution, sensitivity, and heat resistance of positive photoresists. In particular, there is a strong demand for improvement in heat resistance in connection with dry etching.

The present inventors have conducted repeated research to improve the heat resistance of conventional positive photoresists and develop a new photoresist that can meet the above requirements. It has been found that the object can be achieved by containing the polycondensate of (b) and (b) o-benzoquinonediazide sulfonic acid ester or o-naphthoquinonediazide sulfonic acid ester as composition components.

That is, the present invention provides (a) a polycondensate of bis-salicylaldehyde and o-phenylenediamine, and (b) o-phenylenediamine.
The present invention provides a positive photoresist composition comprising -benzoquinone diazide sulfonic acid ester or o-naphthoquinone diazide sulfonic acid ester as a composition component.

The present invention will be explained in detail below.

The polycondensate of bis-salicylaldehyde and O-phenylenediamine used in the composition of the present invention is produced, for example, as follows. Bis-
When salicylaldehyde and o-phenylenediamine are made into a solution using glacial acetic acid and an organic solvent such as tetrahydrofuran and stirred, a polycondensate precipitates out. This is collected, purified using an organic solvent, and dried under reduced pressure.

The above-mentioned bis-salicylaldehyde refers to a compound having a bis structure in which two molecules of salicylaldehyde are bonded via a methylene group or a sulfone group, such as 5,5'-methylene-bis-salicylaldehyde, bis-salicylaldehyde, etc. Examples include 5,5'-sulfone. The above-mentioned bis-salicylaldehyde and o-phenylenediamine can have various substituents within the range that does not impede the purpose of the present invention.

The polycondensate (a) used in the present invention has a decomposition point near 260°C compared to the alkali-soluble phenol formaldehyde novolak resin, which is commonly used as a base resin for positive photoresist compositions. is extremely high, and o in (b) above is extremely high.
-benzoquinonediazide sulfonic acid ester, o
-Good compatibility with naphthoquinonediazide sulfonic acid ester. Furthermore, it has the advantage of good compatibility with various resins such as alkali-soluble phenol formaldehyde novolac resin and m-cresol formaldehyde novolac resin.

When the positive photoresist composition of the present invention is used, the photosensitive resin film formed on the substrate has significantly superior heat resistance compared to conventional products, so post-baking can be performed at a higher temperature. This enables stronger adhesion between the substrate and the resin film. In addition, with conventional products, when post-baking exceeds 140 to 150°C, changes due to heat are significant, resulting in "sagging" and "fogging", making it impossible to form images, whereas with the composition of the present invention, image formation is impossible. Even at temperatures up to 200°C, the purpose of post-baking can be fully achieved without causing "sagging" or "fogging".

Note that the photosensitive resin film formed on the substrate by the composition of the present invention can be formed using a normal developer, for example, an inorganic alkaline developer containing sodium hydrogen phosphate and sodium metasilicate as main components or a quaternary ammonium developer. Development processing can be performed using an organic alkaline developer containing salt as a main component.

The present invention will be described in detail with reference to Examples below.

Example 1 (a) Synthesis of 5,5'-methylene-bis-salicylaldehyde 80 g of distilled salicylaldehyde was mixed with 50 g of glacial acetic acid.
ml, into a solution of 7.0 g of trioxane, and the atmosphere was replaced with nitrogen while stirring well. Then, heat to 90℃ in a nitrogen atmosphere and add 0.5ml of concentrated sulfuric acid and 2.5ml of glacial acetic acid.
Slowly drop the mixed acid. 90-95℃ after dropping
Perform the reaction for 22 hours. After the reaction is completed, the reaction solution is poured into ice water from step 3 and left overnight. After standing, the crystals are collected, thoroughly washed with ether, and recrystallized with acetone to obtain 5,5'-methylene-bis-salicylaldehyde with a mp of 142-143°C in a yield of 48%.

(b) Synthesis of polycondensate of 5,5'-methylenebis-salicylaldehyde and o-phenylenediamine 1.507 g of 5,5'-methylene-bis-salicylaldehyde obtained in (a) above was mixed with 5 ml of tetrahydrofuran and ice. Pour into 20 ml of acetic acid, add a solution of 666 mg of o-phenylenediamine dissolved in 20 ml of glacial acetic acid, and stir. The desired polycondensate polymer precipitated in 10 to 20 seconds, and was washed with methanol and ether and dried under reduced pressure to obtain 1.750 g of polymer. Decomposition point 260℃.

(c) Synthesis of o-naphthoquinone diazide sulfonic acid ester 80 g of o-naphthoquinone diazide-5-sulfonyl chloride and 40 g of phenol formaldehyde novolak resin were dissolved in 900 g of dioxane, and triethylamine was added dropwise at 40 to 50°C to adjust the pH of the reaction solution. to about 8.0. Thereafter, when the reaction is further stirred for about 4 hours, the product begins to precipitate. Take this, wash it with a large amount of pure water, and dry it under reduced pressure.

(d) Preparation of photosensitive solution Add 5 g of the polymer obtained in (b) above to 30 g of N,N-dimethylformamide and 5 g of tetrahydrofuran.
and 5 g of the o-naphthoquinonediazide sulfonic acid ester obtained in step (c) above were dissolved and filtered.

(e) Image formation The photosensitive solution obtained in (d) above is applied to a wafer substrate whose surface has been surface-treated by a conventional method using a spinner to form a coating film of 1.5 μm, and after prebaking at 85°C for 10 minutes, a mask is applied. exposed with an ultra-high pressure mercury lamp. After exposure, develop for 1 minute using developer TMK (manufactured by Kanto Kagaku), wash thoroughly with water, and
After post-baking at ℃ for 30 minutes and etching with a mixed aqueous solution of hydrofluoric acid and ammonium fluoride, an etched image with excellent resolution and dimensional accuracy was obtained. The photosensitive resin film produced also has excellent etching resistance.

Example 2 5 g of the polymer obtained in Example 1 (b), 5 g of the compound obtained in Example 1 (c), and 5 g of phenol formaldehyde novolak resin were dissolved in 30 g of N,N-dimethylformamide, 5 g of tetrahydrofuran, and 10 g of methyl cellosolve. to pass. Thereafter, the same operation as in Example 1(e) was carried out, and an etched image with excellent resolution and dimensional accuracy was obtained.

Claims (1)

[Claims] 1. It is characterized by containing (a) a polycondensate of bis-salicylaldehyde and o-phenylenediamine and (b) o-benzoquinonediazide sulfonic acid ester or o-naphthoquinonediazide sulfonic acid ester as composition components. A positive photoresist composition.