Rapid Sintering and Nondestructive Testing of Nanometal Chip Bonding Layer by Pulsed Current Discharge

Developing new high-performance packaging technologies adapting for the third-generation semiconductors is an urgent need to the related industry applications nowadays. In this work, we reported a novel method for the rapid sintering and nondestructive testing of the nanometal chip bonding layer by pulsed current discharge, which can realize short sintering time (millisecond level), low sintering temperature (< 200 °C), and high bonding strength (>50 MPa). The physical mechanism behind the transient sintering process was revealed based on high-speed observation, infrared measurement, and electrical parameter analysis. The statistical and SEM analysis indicated that the sample resistance and the bonding strength have a negative correlation, which means that the electric characteristics can be used as an important evaluation index for the bonding state. Finally, a practical prediction model for the time-varying resistance of the well-sintered sample (reference curve) was established. On this basis, the nondestructive testing method of the bonding layer and its optimal sintering strategy were proposed. Overall, this work provides a deeper insight into the electrical sintering, proving its promising application prospect.