Patent ID: 8551813

Claim:
An integrated circuit assembly method, comprising: providing a device wafer with plural first posts; forming underfill material comprising a reducing agent around the first posts of the device wafer, wherein the underfill material does not come in contact with the top surface of the first posts; forming solder on the first posts by placing a wafer with a release film having solder thereon to contact the first posts, and then removing the wafer and the release film to leave the solder adhered to the first posts, wherein the release film is made of molybdenum; placing a plurality of dies onto the device wafer, wherein the dies comprise plural second posts corresponding to the first posts, wherein the first posts extend above a substrate surface of the device wafer without voids in the substrate surface surrounding the posts; reflowing the solder to bond the first and second posts; and dicing the device wafer.