Defectivity Yield Improvement Activity to eliminate nitride blisters

Mike Clausen, Jason McMonagle, Bela Green, Gayle Murdoch, Andrew Miller, John Cullen, Jim Moran

Filtronic Compound Semiconductors, UK Tel. +44 1325 306013
Keywords: Via, Blister, MMIC, DMAIC, Six Sigma

The manufacture of GaAs MMIC devices typically requiresthe use of via technology to provide both a heat sink fortemperature control and a low inductance ground for improvedelectrical performance. Filtronic Compound Semiconductorsdesign and manufacture a comprehensive range of MMIC devicewithin their product portfolio. Following completion of themanufacture process, an end of fab visual inspection is carriedout to assess defectivity levels in order to guarantee quality ofproduct to the customer.During a standard end of fab visual inspection, a defect wasobserved in the form of lifting/blistering of the nitride layers inthe vicinity of via pads. This paper reviews how FiltronicCompound Semiconductors instigated a project initiative toanalyze the extent of the problem, implement containmentactivities, introduce countermeasures and control the resultantreduction in defect levels though six sigma methodologies [1]
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