Thin-Wafer Handling with a Heat-Spreader Wafer for 2.5D/3D IC Integration

Abstract

Thin-wafer handling is one of the key enabling technologies for 2.5D/3D IC integration. Usually, it temporary bonds the TSV (through-silicon via)/RDL (redistribution layer) wafer (e.g., passive and active interposers) to a supporting carrier wafer with an adhesive, backgrinds the TSV/RDL interposer wafer to very thin (≤100μm), goes through all the necessary processes, and then de-bonds the thin TSV/RDL interposer wafer from the carrier wafer. In this study, a different route will be taken which eliminates the temporary bonding and de-bonding processes. Emphasis is placed on using a heat-spreader wafer as a supporting carrier wafer during the manufacturing processes and after the assembly is completed (diced), the heat-spreader remains on the thin TSV/RDL interposer. This is a very simple and low-cost thin-wafer handling method for 2.5D/3D IC integration.