Adaptive grinding and polishing of packaged integrated circuits

Preparation of packaged integrated circuits for physical and electrical failure analysis often involves precise grinding and polishing of the thick silicon substrate from the backside. In this work we present an adaptive grinding and polishing technique that incorporates in-situ measurement of thickness and flatness into a five axis CNC machine. Uniformity of remaining silicon thickness is maintained when grinding even as the shape of the die changes during thinning. In turn, polishing time is greatly reduced by precisely following the curved die surface.