Package on Package (PoP) Bonding Structures

摘要

Various embodiments of mechanisms for forming through package vias (TPVs) with multiple conductive layers and/or recesses in a die package and a package on package (PoP) device with bonding structures utilizing the TPVs are provided. One of the multiple conductive layers acts as a protective layer of the main conductive layer of the TPVs. The protective layer is less likely to oxidize and also has a slower formation rate of intermetallic compound (IMC) when exposed to solder. The recesses in TPVs of a die package are filled by solder from the other die package and the IMC layer formed is below the surface of TPVs, which strengthen the bonding structures.

主权项

1. A method, comprising:
forming a seed layer over a carrier substrate; forming a patterned sacrificial layer over the seed layer, the patterned sacrificial layer including an opening exposing a portion of the seed layer, the opening having a substantially uniform diameter from its topmost edge to its bottommost edge; forming a through via having a substantially planar topmost surface and a substantially planar bottommost surface by:
plating a first conductive layer on the seed layer within the opening, andplating a second conductive layer within the opening and on the first conductive layer; removing the patterned sacrificial layer; mounting an integrated circuit die over the carrier substrate; encapsulating the integrated circuit die and the through via in a molding compound; removing a portion of the molding compound to expose a top surface of the integrated circuit die and a top surface of the through via; forming a redistribution structure over the integrated circuit die, the through via, and the molding compound, the redistribution structure electrically contacting the topmost surface of the through via and electrically contacting a contact pad on the top surface of the integrated circuit die; and removing the carrier substrate to expose the bottommost surface of the through via.