Package on Package Bonding Structure and Method for Forming the Same

摘要

The described embodiments of mechanisms of forming a die package and package on package (PoP) structure involve forming a solder paste layer over metal balls of external connectors of a die package. The solder paste layer protects the metal balls from oxidation. In addition, the solder paste layer enables solder to solder bonding with another die package. Further, the solder paste layer moves an intermetallic compound (IMC) layer formed between the solder paste layer and the metal balls below a surface of a molding compound of the die package. Having the IMC layer below the surface strengthens the bonding structure between the two die packages.

主权项

1. A die package comprising:
a semiconductor die attached to a substrate having interconnect structures, wherein the semiconductor die is electrically connected to the interconnect structures; and a first external connector adjacent to the semiconductor die, wherein the first external connector is electrically connected to the interconnect structures, wherein the first external connector is embedded in a molding compound interposed between the semiconductor die and the first external connector, wherein the first external connector comprises:
a first contact pad,a metal ball with a convex surface, wherein the metal ball is bonded to the first contact pad, anda solder paste layer over an upper surface of the metal ball, wherein an upper surface of the solder paste layer substantially conforms to the upper surface of the metal ball, and wherein the solder paste layer has a first portion above an upper surface of the molding compound and a second portion extending lower than the upper surface of the molding compound, wherein the second portion surrounds the first portion.