A thinned semiconductor die is coupled to an integrated heat spreader with thermal
interface material to form a semiconductor package. The method for forming the
package comprises forming a metallization layer on a backside of a thinned semiconductor
die. A thermal interface portion, including a solder layer including a fluxlessly-capable
solder such as AuSn, is formed on a topside of the integrated heat spreader. The
metallization layer and the solder layer are then forced together under load and
heat without flux to bond the semiconductor die to the integrated heat spreader.