International Business Machines Corporation

Augustus C Ouano

James Economy

Nicholas J Clecak

Barbara D Grant

Richard D Balanson

James A Carothers

Beverly L Olsen

A lift-off process for depositing a metallurgy layer on a substrate wherein the improvement is the use of a sacrificial masking layer that is substantially unaffected by exposure to high intensity radiation. The process includes the steps of (1) preparing a resin mixture of a polyaryl sulfone polymer, and a compound of the following: ##STR1## wherein R.sub.1 is a methyl ethyl or an .alpha. branched alkyl group from 3 to 10 atoms, R.sub.2 is a hydrogen, methyl, ethyl or a branched alkyl group of from 3 to 10 carbon atoms, and X has a value of 1 to 6, and Z is an aliphatic hydrocarbon of the formula C.sub.5 H.sub.8 the compound being present in the amount of from 0.5 to 3.5% by weight of the polyaryl sulfone resin, (2) depositing a blanket sacrificial masking layer of the resin mixture on the surface of the semiconductor wafer, (3) selectively removing areas of the blanket masking layer to define the image of the desired metallurgy pattern, (4) depositing a blanket layer of conductive metal, and (5) exposing the resultant coated wafer to a solvent for the polyaryl sulfone resin to remove the masking layer in all the overlying metal areas.

Lift-off masking method

The present invention is concerned with enhancement of resist development. In particular it is concerned with obtaining high solubility rate ratio between the exposed and the unexposed regions of a resist and also obtaining shorter development time. These objectives are achieved by treating the resist with a liquid trialkylamine having from two to eight carbon atoms in each alkyl group.

Enhancement of resist development

Phenolic-aldehyde resins sensitized with Meldrum's diazo or a homologue thereof are useful as lithographic resists sensitive to deep ultra-violet light.

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Santa Cruz, CA, United States of America

Augustus C Ouano