Process for forming mask patterns of positive type resist material with trimethylsilynitrile

Claim 2

A process for forming mask patterns of positive type resist material with trimethylsilylnitrile, comprising steps of (a) forming a first resist layer on a wafer for planarizing the wafer surface; (b) forming a second resist layer on said first resist layer, the second resist layer consisting essentially of, a photoactive resin having phenolic hydroxyl groups selected from the group consisting of an admixture of a naphthoquinone diazido sulfonic acid derivative compound and a phenol formaldehyde, and an ester of the reaction of a naphthoquinone diazido sulfonic acid derivative compound and a phenol formaldehyde, and 5 to 50% by weight of trimethylsilylnitrile based on the solid content of the positive resist material, wherein said first resist layer has a higher plasma etch rate than said second resist layer; (c) selectively exposing on said second resist layer to form a pattern in that layer; (d) removing exposed portions of said second resist layer to form a mask pattern in exposed portions of said second resist layer; and (e) subjecting said mask pattern and said first resist layer to a reactive ion etching to remove the first resist layer by using the mask pattern as an etching mask.

Claim 3

A process as claimed in claim 1, in which said process further comprises the step of; baking said wafer between the steps (a) and (b).

Claim 4

A process as claimed in claim 2, in which said baking is at about 150° C. for about 30 minutes.

Claim 5

A process as claimed in claim 1, in which said first resist layer has a thickness of about 2 to 5 um.

Claim 6

A process as claimed in claim 1, in which said second resist layer is formed by spin-coating.

Claim 7

A process as claimed in claim 1, in which said second resist layer has a thickness of about 0.5 to 1 um.

Claim 8

A process as claimed in claim 1, in which said exposure energy is ultraviolet rays, electron beams or ion beams.

Claim 9

A process as claimed in claim 1, in which said removing step is immersing the wafer in a photographic developer for about 1 minute.

Claim 10

A process as claimed in claim 1, in which said reactive ion etching is oxygen plasma etching.

Claim 11

A process as claimed in claim 1, in which said process further comprises the step of; selectivily etching the wafer by using both said mask pattern and first resist layer as a two layer mask so as to form an opening therein.

Claim 12

A process as claimed in claim 10, in which said etching is an F 2 plasma etching.

Claim 13

A process for forming mask patterns of positive type resist material with trimethylsilylnitrile, comprising the steps of; (a) forming a first resist layer on a wafer for planarizing the wafer surface; (b) forming a second resist layer on said first resist layer the second resist layer consisting essentially of: a base material solution forming a positive resist pattern, said base material solution being composed of a photoactive resin having phenolic hydroxyl groups selected from the group consisting of a naphthoquinone diazide sulfonic acid derivative compound and a phenol formaldehyde, and an ester of the reaction of a naphthoquinone diazide sulfonic acid derivative compound and a phenol formaldehyde, and 5to 50% by weight of trimethylsilylnitrile based on the total weight of the solid content of the positive type resist solution; (c) selectively exposing said second resist layer to energy to form a pattern in that layer; (d) removing exposed portions of said second resist layer to form a mask pattern in exposed portions of said second resist layer; and (e) subjecting said mask pattern and said first resist layer to a reactive ion etching to remove the first resist layer by using the mask pattern as an etching mask.

Claim 14

A process for forming mask patterns of positive type resist material with trimethylsilylnitrile, comprising the steps of; (a) forming a first resist layer on a wafer for planarizing the wafer surface; (b) forming a second resist layer on said first resist layer the second resist layer consisting essentially of: a base material solution forming a positive resist pattern, said base material solution being composed of a photoactive resin having phenolic hydroxyl groups selected from the group consisting of a naphthoquinone diazide sulfonic acid derivative compound and a phenol formaldehyde, and an ester of the reaction of a naphthoquinone diazide sulfonic acid derivative compound and a phenol formaldehyde, and 5to 50% by weight of trimethylsilylnitrile based on the total weight of the solid content of the positive type resist solution; (c) selectively exposing said second resist layer to energy to form a pattern in that layer; (d) removing exposed portions of said second resist layer to form a mask pattern in exposed portions of said second resist layer; and (e) subjecting said mask pattern and said first resist layer to a reactive ion etching to remove the first resist layer by using the mask pattern as an etching mask.

Claim 15

A process as claimed in claim 12, in which said process further comprises the step of; baking said wafer at about 150° C. for about 30 minutes between the steps (a) and (b).

Claim 16

A process as claimed in claim 12, in which said first resist layer has a thickness of about 2 to 5 um.

Claim 17

A process as claimed in claim 12, in which said second resist layer is formed by spin-coating.

Claim 18

A process as claimed in claim 12, in which said second resist layer has a thickness of about 0.5 to 1 um.

Claim 19

A process as claimed in claim 12, in which said exposure energy is ultraviolet rays, electron beams or ion beams.

Claim 20

A process as claimed in claim 12, in which said removing step is immersing the wafer in a photographic developer for about 1 minute.

Claim 21

A process as claimed in claim 12, in which said reactive ion etching is oxygen plasma etching.

Claim 22

A process as claimed in claim 12, in which said process further comprises the step of; selectivily etching the wafer by using both said mask pattern and first resist layer as a two layer mask so as to form an opening therein.