A novel stacking method of filling hole used in package on package

With the developing of the electronics industry, 3-D package stack has been a new trend. Currently, most of the package on package (POP) stack adopted the bump interconnection with the solder balls, resulted in some issues, such as bridging, shifting and warpage. In this paper, a novel stacking method is presented to solve the problems of interconnection and stacking accuracy mentioned above. The insulating medium was adhered to the substrate; a hole was drilled according to the interconnection requirement. Then the hole is filled with copper and interconnects the substrates through the insulating medium. Meanwhile, this lead-free soldering stacking method of filling hole adapt to the global green manufacturing trend.