The effect of reworkable edgebond adhesive on the board-level reliability of larger WLCSPs

The demand for reliable wafer level chip scale packages (WLCSPs) is getting higher due to the need for higher performance and smaller form factor designs. Small WLCSPs have been used with good board-level reliability but larger WLCSPs have not. In the study, a high Tg, low CTE reworkable edgebond adhesive is proposed to enhance the board-level solder joint reliability of a large WLCSP having a chip size of 8 mm. Two types of thermal cycling conditions are considered: 0-100°C (normal condition) and 25-125°C (elevated condition). Finite element analysis using ANSYS is performed to simulate the board-level solder joint reliability of the WLCSP with and without the edgebond adhesive. The simulation results are compared with each other and also with the literature experimental data. Results show that the edgebond adhesive can significantly enhance board-level reliability of large WLCSPs.