Lift-off masking method

Claim 1

An improved lift-off process that is tolerant of high intensity radiation for depositing a metallurgy layer on a substrate comprising preparing a mixture of a polyaryl sulfone polymer, and a compound of the formula ##STR7## where R 1 is methyl, ethyl or an α branched alkyl group of from 3 to 10 carbon atoms, R 2 is hydrogen, methyl, ethyl or an α branched alkyl group of from 3 to 10 atoms, X has a value of from 1 to 6, and Z is the aliphatic hydrocarbon of the formula C.sub.5 H.sub.8 wherein said compound is present in the mixture in an amount in the range of from 0.5 to 3.5% by weight, of the mixture, depositing a blanket sacrificial masking layer of said mixture on the surface of said substrate and heating to harden the layer, selectively removing areas of said blanket sacrificial masking layer to expose surface areas of the substrate to produce openings that define the image of the desired metallurgy pattern, depositing a blanket layer of metal over the surface of said hardened sacrificial masking layer and the exposed surface areas of said substrate, the carrying out of said step of selectively removing areas of the sacrificial masking layer and/or the step of depositing a blanket layer of metal incorporating the use of high intensity radiation, and exposing the resultant layered substrate to a solvent for the polyaryl sulfone polymer material of said sacrificial masking layer thereby removing said masking layer and the overlying metal layer areas but leaving intact the metal layer areas in said openings in contact with said substrate.