High density metal-metal interconnect bonding with pre-applied fluxing underfill
Gregory, C., Lueck, M., Huffman, A., Lannon, J. M., & Temple, D. S. (2012). High density metal-metal interconnect bonding with pre-applied fluxing underfill. In 2012 IEEE 62nd Electronic Components and Technology Conference (ECTC 2012), San Diego, CA, May 29-June 1, 2012, pp. 20–25. .
The results of initial investigations incorporating a fluxing wafer level underfill (WAUF) into a Cu/Sn-Cu intermetallic bonded device are presented. The studies were performed utilizing a 640 × 512 high density area array test vehicle (105 interconnects/cm2). The fluxing pre-applied wafer level underfill was integrated into a solid-liquid diffusion bonding process which achieved an interconnect yield of 99.99%. Bond formation, underfill encapsulation, and electrical yield were evaluated using several imaging techniques and electrical testing. These results and results from reliability testing of the primary sample set are presented.