Sequential Plasma Activation Bonding of Sapphire using SiO2 Intermediate Layer

Al2O3 is widely employed for electronics applications as an optical, dielectric, mechanical material, and its bonding has an important role to fabricate and package the devices. In the previous studies, it was reported that the sequential plasma activation bonding (SPAB) was an effective approach to enhance the bond strength of SiO2 materials at low temperature, but not for Al2O3. Therefore, we propose the low temperature sapphire bonding using SPAB by introducing SiO2 intermediate layers. For this, in this study, we investigate the applicability of SPAB to the deposited SiO2 layer on sapphire wafers by reactive sputtering. The SiO2 layer has a suitable surface smoothness and composition, which are comparable to the fused silica. The experimental result shows the applicability of SPAB to the sapphire bonding via SiO2 intermediate layer.