Wafer Substrate Impact on Direct Wafer-to-Wafer Bonding Process

Direct wafer-to-wafer bonding is a unique integration scheme in semiconductor manufacturing that enable two dissimilar wafers to be joined together. However, misalignment along the bond interface increases overlay error and reduces device performance. This paper investigates the bonding process related distortion effects from silicon wafer crystalline orientation. Simulations and experiments show that the wafer substrate's crystalline structure results in a four-fold symmetrical post-bond distortion fingerprints. The results provide insights to optimize bonder process to address the distortion challenges in advanced device integration applications.