A flexible, high density decal and the use thereof methods of forming detachable electrical interconnections between a flexible chip carrier and a printed wiring board. The flexible decal has fine-pitch pads on a first surface and pads of a pitch wider than the fine pitch on a second surface, the fine-pitch pads on the first surface designed to electrically connect to a semiconductor device, and the wider-pitch pads on the second surface designed to electrically connect to a printed wiring board or the like. The pads on the first surface are conductively wired to the pads on the second surface through one or more insulating levels in the flexible decal.