MASKING SHEET FOR ASSEMBLING SEMICONDUCTOR DEVICE AND METHOD FOR ASSEMBLING SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a masking sheet capable of stably producing a semiconductor package such as QFN(quad flat non-load) through suppressing the overhang of resin sealing agent and adhesive transfer in assembling a semiconductor device. SOLUTION: This masking sheet for assembling a semiconductor device is such as to be releasably adhesive to a lead frame. This masking sheet is obtained by providing an adhesive layer of silicone-based adhesive on a heat- resistant film <=150 deg.C in glass transition temperature and 10-50 ppm/ deg.C in linear expansion coefficient at 150-200 deg.C, being characterized by being <=5 wt.% in weight loss percent when heated at 180 deg.C for one hour; wherein it is preferable that the silicone-based adhesive is a polydimethylsiloxane-based one or consists mainly of a polyalkyl alkenylsiloxane and a polyalkylhydrogensiloxane. The other objective method for assembling a semiconductor device comprises the steps of first subjecting the mashing sheet to pressure contact on a lead frame and releasing it after the semiconductor device is assembled.