A packaging solution utilizing adhesive-filled TSVs and flip–chip methods

Abstract

A compact packaging solution for microelectromechanical systems (MEMS) devices is presented. The 3D-integrated packaging solution was designed for the instrumentation of a spinal screw with a wireless sensor array, but may be adapted for a variety of applications. To achieve the compact package size, an unobtrusive through-silicon via (TSV) design was added to the microfabrication process flow for the MEMS sensor. These TSVs allowed vertical integration of the MEMS devices onto flexible printed circuit boards (FPCBs) using a flip-chip system. Ohmic connections with resistance values below 1 have been achieved for 100 μm TSVs in 300 and 500 μm substrates. This paper describes the design and microfabrication process flow for the TSVs, and provides details on the flip-chip techniques used to electrically and structurally connect the MEMS devices to the FPCBs.