In this report, we will discuss the behavior of mold type POL (Power Over Lay) tiles under thermal stress and the challenges they face. Temperature cycling tests were performed on several POL tile Cu wiring designs and mold resin combinations. The combination of the design with Cu wiring on the entire surface of the device and the use of high-toughness molding resin was demonstrated high reliability in temperature cycles. Thermal stress analysis results using a full-scale model of POL tile with this combination showed decrease in plastic strain at Cu via connection and low damage level at pad opening portion.
