SILICON-CARBON RESIN (GLOB TOP) OVER SILICONE DIE COAT FOR REDUCED STRESS ENCAPSULATION
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2002-Jan-03
Extensive reliability testing of epoxy glob top mate- rials have shown that they have reduced environmental performance. over ceramic chip carriers and molded plas- tic packages such as PLCC, QFPs, TSOPs, or OMPACs. Failure analysis has shown that corrosion of the metallization, die or passivation cracking and crazing, and surface metal shifting contribute to this reduction in reliability. As the size of the IC increases, the prob- lems associated with mechanical stress only get worse. In this work new coating materials are combined with existing silicone die coat resins to provide a unique com- bination of a soft stress-absorbing moisture barrier on the die surface with a hard, tough top coat to provide the mechanical protection of the package. As a result, mechanical and environmental stability of the underly- ing IC is greatly improved; the potential for IC failure due to corrosion, die cracking, passivation crazing, or surface metal shiiing is reduced.