High Yield Embedding of 30μm Thin Chips in a Flexible PCB using a Photopatternable Polyimide based Ultra-Thin Chip Package (UTCP)

摘要

A thin chip package for off-the-shelf ICs is developed which enables the embedding of these chips into a flexiblecircuit board. The package consists of a copper fan-out on a polyimide substrate, in which the thinned IC (30?m) isembedded. These packages are subsequently integrated in a standard flexible circuit board (FCB). A microcontrollerand a proprietary DSP processor are embedded using this technology. The yield of the Ultra-Thin Chip package(UTCP) was measured before embedding in the circuit board, and reaches up to 87% for the packagedmicrocontrollers (MSP430 family, known-good dies). The yield on the DSP processor was measured to be 62%.After embedding in the FCB, 95% of the functional UTCP-packaged dies are still functional.