A new transferred ultra-thin silicon micropackaging

We report on a novel device-scale packaging by transferring an ultra-thin silicon (UTSi) capping structure, which may encapsulate microdevices. The UTSi was fabricated to form a recessed structure on the carrier glass, and then transferred on to a host substrate, thus forming a micro encapsulation. In this approach, the flip-chip assembly and tether-broken techniques are successfully utilized in demonstrating the transferred microcap on the selective area of the host substrate that is aligned through the transparent glass. Furthermore, the robustness of the UTSi microcap is even superior to those used in the poly-Si surface micromachining technique due to the high stiffness structure. As a result, the micro encapsulation presents a new packaging technique with advantages of area-selective three-dimensional micropackaging, hermetic sealing, robustness, integrated circuit packaging process compatibility and, potentially, wafer level packaging.