Machine Thinning of Gallium Arsenide (GaAs) Wafers

The public domain literature contains no information concerning one pass diamond turning (micromachining). It is a process that has the potential of achieving wafer thickness, and parallelisms that exceeds the quality of present day lapping and polishing practices. The principal investigator has had extensive experience in backside thinning having recently published a Final Report WRDC-TR-90-4139 entitled "evaluating Micromachined GaAs Wafers". The information in this proposal is an extension of that earlier work and it shows that one pass thinning of GaAs has a high probability of succeeding. However, diamond turning machines (DTM) in general must be modified before they can achieve high quality thickness control and parallelity under competitive production conditions. The modifications necessary to convert and industry standard DTM (Moore Special tools m-18 AG) into a competitive backside thinning machine is conceptually provided. Phase I delivers one thinned GaAs wafer (100 micron thick) with a full physical and electronic characterization. In Phase II groups of wafers will be thinned so that the full extent of subsurface damage can be evaluated. Testing is planned to conclusively prove that one pass thinning is competitive or better than present day lapping and polishing.