Patent ID: 7651891

Claim:
A method for creating an air cavity in a molding compound for an integrated circuit die, said method comprising: coating a thermally decomposable material on a wafer including a plurality of integrated circuit units; patterning the coated material into a sacrificial layer such that the sacrificial layer covers a desired portion of each integrated circuit unit; coating a polymer material on the wafer over the sacrificial layer; patterning the polymer material into a structural layer covering the sacrificial layer; sawing the wafer into individual dice, each die including a corresponding integrated circuit unit; attaching dice to a carrier (die attach pads etc.) and provide electrical connections; covering the dice on the carrier with an encapsulant material; and heating the encapsulant material, wherein the sacrificial layer decomposes and outgasses through the structural layer and the encapsulant material, thereby leaving an air cavity.