Pad array carrier ic device using flexible tape

Abstract

An electronic pad array carrier IC device for mounting on a printed circuit board (PCB) or flex circuit substrate has a thin, flexible 'tape' substrate having a plurality of traces. The substrate may be a polyimide or other material that can withstand relatively large lateral mechanical displacement. An integrated circuit die is mounted in proximity with or on the substrate and electrical connections between the integrated circuit chip and the traces are made by any conventional means. The substrate traces are provided at their outer ends with solder balls or pads for making connections to the PCB. A package body covers the die, which body may be optionally used to stand off the package a set distance from the PCB so that the solder balls will form the proper concave structure. Alternatively, a carrier structure may be provided around the periphery of the substrate to add rigidity during handling, testing and mounting, but which may also provide the stand-off function. The thin, flexible substrate can absorb a relatively large lateral or even vertical mechanical displacement over a rather large package area that may accommodate as few as 20 or as many 500 or more connections. The substrate may be optionally transparent or translucent to permit inspection of the bonds after mounting to the PCB. The PCB or flex circuit may also be transparent or translucent for bond inspection purposes. The solder pads or balls may be joined to a via through the substrate at least partially filled with electrically conductive material to permit back side testing of the carrier before or after mounting of the package to the PCB. Additionally, a heat sink structure may be directly bonded to the die in the pad array carrier IC device.