Preparation of fragile devices

Abstract

A method of fabricating a generally planar device such as a lead frame, having fragile portions contiguous respectively with relatively robust portions, which includes in sequence, the steps of providing a robust, generally sheet-like blank, removing material from selective portions of a surface layer of the blank at one of its main surfaces to define first portions of the surface layer to be the relatively robust portions in the finished device and second portions to be fragile portions of the finished device, firmly embedding the second portions in a fixing material layer, and removing material from the other main surface of the blank in the region of the embedded portions to a sufficient depth to expose an underside of the surface layer, thereby to isolate the embedded portions from each other and to render them thinner and thus more fragile than the first portions. With such a method, there is fabricated a generally planar lead frame including several leads, each having a relatively robust portion and a contiguous, relatively fragile portion thinner and more narrow than the robust portion, the fragile portion having a flat face. The lead frame further includes a flat support in the plane of the lead frame, all of the fragile portions being embedded in the flat support such that only the flat face of each fragile portion is exposed in the plane for electrical contact, and each fragile portion is as wide at the flat face as it is beneath that flat face.

Dependencies are inferred from the claim text.