基于半桥MOSFET芯片铜带夹扣堆叠的电源SiP设计

Design of Power SiP Based on Copper Clip Stacked Half-bridge MOSFETs

采用系统级封装(System in Package,SiP)设计是实现电源小型化的有效方式之一。同步BUCK DC-DC变换器中的半桥功率开关MOSFET,通过堆叠工艺利用纵向空间,将芯片的占用面积降低了36%。MOSFET芯片表面做焊锡浸润材料金属化处理,直接与铜带夹扣锡膏烧焊,将电流路径电阻减小了约10倍,同时热传导效率得到了改善。通过多芯片微组装工艺,将电源控制器、MOSFET芯片、电感器及其他必要器件集成在BGA陶瓷封装内。研制的电源SiP样机尺寸为20 mm×18 mm×4.8 mm,可双通道独立输出15 A,或双通道并联输出30 A电流,电源转换效率达93%以上。

System in package(SiP)is one of the most effective approaches to realize miniaturize power products.This paper proposes to stack up the half-bridge MOSFETs in synchronous BUCK DC-DC converter.By use of the vertical space,the circuit size of MOSFETs is reduced by 36%.The surface of MOSFETs is metallized for solder paste with copper clip.As a result,the resistance of current path is reduced by 10 times approximately,and the thermal conductivity is improved.The power management controller,MOSFETs,inductor and other auxiliary components are integrated to a BGA ceramic package.The developed power SiP prototype has a size of 20mm×18mm×4.8mm,and capability of loading 15A by one channel independently or 30A by two channels in parallel.The power conversion efficiency is up to 93%.