UCLA

Historically, silicon contact bonding has been used for silicon-on-insulator fabrication. However, there is little published research on contact bonding for bulk silicon applications. For these applications to be successful, contact bonding must be mechanically stable for bulk objects and a non-destructive characterization technique must be designed to evaluate bond quality. This report analyzes the tensile strength of two bonding processes, an alcohol-assisted (AA) and a direct-bonded (DB) process, and the potential of acoustic microscopy (AMI) to evaluate bond quality. Samples were aged in ambient for extended durations. In addition, some were annealed at 150oC for 30 minutes to determine low-temperature annealing effects. DB samples held significantly higher loads than AA samples and consistently held above 2 MPa at room-temperature, which increased to 4 MPa after annealing. A linear correlation was ultimately found between AMI results and the tensile strengths of DB samples but not AA samples.