A new reworkable edgebond adhesive* from Zymet has been shown to enhance the board-level reliability of a large wafer-level chip-scale package (WLCSP).  The work was performed in a collaborative effort between Portland State University, Cisco, and Zymet, and published in the Proceedings of the SMTA International 2016 conference, which took place in Rosemont, Ill. (“Reworkable Edgebond Applied Wafer-Level Chip-Scale Package (WLCSP) Thermal Cycling Performance Enhancement at Elevated Temperature”). Additional work was published in the 66th Electronic Components and Technology Conference proceedings: “Effect of Local Grain Distribution and Enhancement on Edgebond Applied Wafer-Level Chip-Scale Package (WLCSP) Thermal Cycle Performance.” 

In the study, 8 x 8 mm WLCSPs, assembled on an organic substrate, were subjected to 0-100°C thermal cycling. Absent the adhesive, first failure occurs at 355 cycles and characteristic life is 638 cycles. With the reworkable edgebond adhesive, however, no failures were encountered at 2,000 cycles, end of test.