Patent ID: 8021925

Claim:
A method of forming a semiconductor module, said method comprising: mounting a die, having a periphery, on a substrate; covering said die with a planar lid having an outer rim such that, after said covering of said die with said lid, said lid extends horizontally beyond said periphery of said die and said outer rim contacts said substrate so as to ensure that a bottom surface of said lid remains separated from a top surface of said die by a gap; before said covering of said die with said lid, depositing a thermal compound on at least one of said top surface of said die and a corresponding portion of said bottom surface of said lid such that, after said covering of said die with said lid, said thermal compound fills said gap without extending laterally beyond said periphery of said die; and forming a barrier such that, when said lid covers said die, said barrier extends vertically between said lid and said substrate, is positioned laterally between said outer rim and said die and surrounds and is immediately adjacent to said periphery of said die so as to contain said thermal compound within said gap, said forming of said barrier further comprising: selecting a polymer material; depositing said polymer material on at least one of said lid and said substrate such that, when said lid covers said die, said polymer material extends between and contacts both said substrate and said lid; and curing said polymer material to form said barrier such that said barrier comprises a single layer of flexible cured polymer that adheres directly to both said lid and said substrate, said selecting, said depositing and said curing being performed such that said barrier flexes in response to expansion and contraction of said substrate and said lid during temperature cycling of said semiconductor module.