SU913320A1 - Positive photoresistor - Google Patents

Description

The invention relates to positive photoresists, which are used in photolithographic processes with. the manufacture of integrated circuits in microelectronics, electronics and other industries.

A positive photoresist is known, including 1,2-naphthoquinone diazide (2) -5-sulfonic acid ether and iodinated diphenylolpropane, phenol-formaldehyde novolac resin and dioxane. This resist has a high sensitivity and resolution [1].

However, its disadvantage is the instability of properties in time and from batch to batch.

Also known is a positive photoresist, which includes the diester of 1,2-yaaftohinodiazide- (2) -5-sulfonic acids and 2,4,4'-trioxybenzophenone, phenol-formaldehyde novolac resin with molecular mass distribution (MMP) = 100-10000, phenol-formaldehyde resin novolac resin, with a mass distribution (MMP) = 100-10000 = 20020000, sodium salt of 1- (4 * -phenoxy3'-sulfophenyl) -3 ^- stearoylaminot4 (4 * hydroxy-2 "-chlorophenylazo) -pyrazolone-5, diethylene glycol dimethyl ether and dimethylformamide [2].

2

The specified photoresist has a high resolution and low microdeficiency, but its properties

5 also not stable in time and from batch to batch.

The closest to the proposed is a positive photoresist, including the diester of 1,2-naphthoquinone diazide 10 (2) -5-sulfonic acid and 2,4,4'-trioxybenzophenone, phenol-formaldehyde novolac resin and diethylene glycol dimethyl ether. This photoresist has a relatively high light. sensitivity, high rareresha15. ability and low density punctures [3].

The disadvantages of the known photoresist is the low reproducibility

__ its properties from batch to batch> and low (no more than 4 days) storage stability, which complicates its use under production conditions.

The purpose of the invention is to increase the batch-to-batch production of the photoresist properties of the photoresist and increase its storage stability.

This goal is achieved by

that a positive photoresist, including a 1,2-naphthoquinone diazide- (2) 3 diester

913320

four

5-sulfonic acids and 2,4,4'-trioxybenzophenone, phenol-formaldehyde novolac resin and diethylene glycol dimethyl ether, additionally contains 1,2-naphthoquinon-diazide- (2) 5-sulfonic acid ester and oxybenzalacetone and monomethyl ethyl acetate glycol ether and ethylene glycol ether and ethylene glycol ether and ethyl acetate and ethylene glycol ether and ethylene acetate and ethylene glycol; %:

Diester of 1,2-naphthoquinonediaed- (2) -5-sulfonic acids and 2,4,4'-trioxybenzophenone 1-18 ten Ester of 1,2-naphthoquinonediazide- (2) -5-sulfonic acids and hydroxybenzal 15 acetone 1-18 Phenol formaldehyde novolac resin 15-26,7 Dimethyl ether 20 diethylene glycol 40-60 Acetate Ethylene Glycol Monomethyl Ether Rest The essence of the invention is

The fact that the introduction into the composition of a photoresist as a photosensitive component of a mixture of two naphthoquinone diazide sulfonic esters of various structures prevents the formation of a regular crystalline structure capable of causing precipitation and thus increases the reproducibility of photoresist properties from batch to batch and in time.

When the content of either of the two naphthoquinonediazide sulfoesters, 35 included in the photosensitive component, did not prevent less than 1 wt.%, The reproducibility of the photoresist properties does not increase, and when the content of any of the two naphthoquinone diazide sulfo ethers is reached, 18 wt. % decreases the reist properties of the photoresist, a decrease in contrast.

Example. Photoresists are prepared by dissolving phenol-formaldehyde novolac resin and photosensitive esters in organic solvents, followed by filtering the solutions through a filter with a pore size of 0.5 μm. The resulting solutions are kept in the dark during the day and up to 6 months. Photoresist films are obtained by applying a solution onto a technological substrate by centrifuging. After drying in air for 20 minutes and heat treatment at 90 + 5 C for 20 minutes, a layer of photoresist on the substrate is irradiated with UV light through a photo mask and the image is subsequently developed with a 0.4% aqueous KOH solution for 40 s. The obtained protective relief with the size of elements up to 1 micron is used to create microcircuits.

Table 1 shows the composition of the studied photoresists? in tab. 2 properties of photoresist of 6 different batches; in tab. 3 - properties of the proposed compositions of photoresist and known depending on the time of support.

As can be seen from the table. 2, the photoresist of composition 6, which has optimal properties, shows a high batch-to-batch reproducibility of properties from batch to batch. The compositions were tested for the seventh day

precipitation takes place and, consequently, ki after cooking. T a b l and c a 1 Photoresist Components Composition photoresist, weight. % .2.1 ² '1 ³ 1 four 1 s AND 7 1 8 I Famous The diester of 1,2-naphthoquinonediazide- (2) -5 sulfonic acids and 2,4,4 * -trioxybenzophenone 9 about one 18 2 6 10.2 12 12 15 1,2-naphthochi ester - nonazide- (2) -5 sulfonic acid and hydroxybenzalacetone one 9 2 18 6 1.8 2.3 3 Phenol formaldehyde novolachnaya resin 20 20 20 20 1θ 18 26.7 15 15 Diethylene glycol dimethyl ether 40 60 40 40 50 50 40 ' 50 70 . Acetate Ethylene Glycol Monomethyl Ether thirty ten 20 20 20 20 20 20

$

913320

6

Table 2

The consignment Photoresist Microdefects in the form of punctures def / clA Microdefects in the form of punctures / def / cm ¹ Contrast, relative units Composition 6 one 0 0.01 25 2 0.01 0.01 26 3 about 0.02 25 Famous one 0 0.8 22 2 Oh ¹ 23 eight 3 0.06 ten 18

Table3

The composition of the photoresist " The duration of the composition before the study, days Microdefectability in the form of punctures def / s (A Microdefectness in the form of unmanifested inclusions, def / cm² Contrast, relative units one 0.01 0.1 23 one 7 0.01 0.1 23 one 0.01 0.05 20 2 7 0.01 0.05 20 one 0 0.1 22 3 7 0 0.1 22 one 0 0.01 20 four 7 0 0.01 20 one 0.01 0.01 21 five 7 0.01 0.01 21 180 0.01 0.02 21 one 0 0.01 24 6 7 0 '. 0.01 24 180 0 . 0.01 24 one 0.02 0.04 21 7 7 0.02 0.04 21 one 0.01 0.01 22 eight 7 0.01 0.01 • 22 Famous one 0.01 0.2 22 - four 0/1 ? 25 eight

Heavy precipitate

913320

In tab. 3 shows the reproducibility of the properties of photoresist formulations. from time. The well-known photoresist, containing in its composition the same batch of 1,2-paftoquinondiazide (2) -5-sulfonic acid and 2,4,4'-trioxybenzophenone diester, has a low puncture density and acceptable density of undeveloped inclusions a day after preparation; on the fourth day, these parameters increase 10 and 120 times respectively, and the contrast decreases to an unacceptable value.

Thus, the use of the proposed composition of photoresist provides in comparison with the known '15

reproducibility of photoresist from batch to batch and in time. The use in the proposed composition of a mixture of two solvents instead of one as compared to the known one improves the quality of the photoresist film due to its more uniform drying during heat treatment. A different compared to the known ratio of the photosensitive and film-forming components in the photoresist contributes to the reproducibility of its properties and reduces the cost of the photoresist due to

saving expensive naphthoquinonediazide sulfoesters. _ _p

zofenone, phenol-formaldehyde novolac resin and diethyleneglycol dimethyl ether, characterized in that, in order to increase the reproducibility of properties from batch to batch and increase storage stability, it additionally contains 1,2-naphthoquinone-diazide- (2) -5-sulfonic acid ether and hydroxybenzalacetone and ethyl acetate glycol monomethyl ether in the following ratio, wt. %:

Diester of 1,2-naphthoquinonediazide- (2) -5-sulfonic acids and 2,4,4'-trioxybenzophenone 1-18

Ester 1,2-naphthoquinone diade- (2) ’- 5-sulfonic acid and hydroxybenzalacetone

Phenol-Formal Hydro-novolac Resin Diethylene Glycol Dimethyl Ether Methyl Acetate Methyl Ether

1-18

15-26,7

40-60

Rest

Sources of information taken into account in the examination

1. USSR author's certificate ’

No. 421548, cl. H 01 L 21/312, published 11968.

'

Claims (3)

Claim Positive photoresist, including diester 1 , 2-naphthoquinone-diazide- (2) -5 sulfonic acid and 2,4,4 * trioxyben2. USSR Author's Certificate No. 679923, cl. From 03 From 1/68, published. 1979 3. USSR author's certificate No. 530568, cl. From 03 From 1/68, published. 1974 (prototype). ι