Lift-off masking method

摘要

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: wherein R1 is a methyl ethyl or an alpha branched alkyl group from 3 to 10 atoms, R2 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 C5H8 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.