Development of Novel Methods for Grinding and Polishing of 3DHI Devices

Abstract Novel sample preparation techniques have been developed for Three-Dimensional Heterogeneously Integrated (3DHI) devices to enable precise failure analysis while protecting adjacent components. Traditional grinding and polishing methods risk damaging surrounding areas when tool bits extend beyond the target region. Using the VarioMill system's high-precision stages (±1µm accuracy), we introduce three key innovations: a helical grinding approach for accessing die centers, an extended tool bit technique for processing rectangular corners, and enhanced polishing protocols. These methods allow for targeted sample preparation of individual dies or specific die regions while completely preserving adjacent components. The techniques are particularly valuable for complex, densely packed 3DHI devices where conventional preparation methods pose significant risks of collateral damage.