Just to give an idea of what can be the breakage rates of 6 inch GaAs wafer. It seems to be far better than some numbers that we have heard here.
GaAs Wafer Breakage may, 2014
INTRODUCTION
GaAs wafer breakage has been accepted as a norm because of the extreme brittleness of wafers [1-3]. Historically, in the three inch wafer size days, 18% rate was not unusual. As the volume and size of the wafers grew, high rates became unacceptable. Today, using 150 mm (6 inch) wafers, the raw material cost has dropped significantly due to the high volume, but
epi wafers are invariably used for commonly used III-V products. Therefore, finished product wafer cost remains a challenge.
Breakage rates had settled down at about 2% in the last decade. The run rates are in thousands of wafer per week.
Fab yields are running around 95 % and probe yields are approaching 99 %. At a breakage rate of 2%, it is the highest
Pareto item among the causes of yield loss. Skyworks has reduced breakage levels from few percent to below 0.5% (measured as wafers broken as a fraction of wafer outs plus wafers broken). Fig. 1 shows the reduction of wafer breakage over a few years’ time. Fab
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wide initiatives and improvements to achieve this reduction are discussed in this paper. This rate does not include operator errors that result in whole-lot breakage. Only minor
breakage defined as breakage of fewer than five wafers per event are included in the current study.
