Investigations of strength of copper-bonded wafers with several quantitative and qualitative tests

The strengths of Cu-bonded wafers with respect to different bonding temperatures and bonding durations by quantitative and qualitative approaches were reviewed and investigated. These investigations include the mechanical dicing test, the tape test, the pull test, and the push test. For all test results, the strength of Cu-bonded wafers increases with increases in bonding duration or bonding temperature. Thermal anneal after bonding improved the bonding strength only at the high bonding temperature and not at the low temperature.