Mechanical reliability effects of back-grinding upon GaAs LSI chips

The brittle damage layer of background GaAs LSI chips has been investigated through fracture toughness experiments, etching rate measurements, and SEM (scanning electron microscope) observations. The rough grinding damage which has a negative influence on the mechanical reliability of GaAs LSI chips penetrates to a 5-/spl mu/m depth on the finished surface. This is a little larger than than expected because the ductile damage layer due to rough grinding is only 0.6 /spl mu/m thick. However, this damage can be completely removed by 5-/spl mu/m mirror grinding and 1-/spl mu/m chemical etching, because the mirror grinding damage generates a 0.6-/spl mu/m-thick ductile deformation layer and a negligibly thin brittle deformation layer, which do not influence mechanical reliability. >