CHARACTERIZATION OF THE INFLUENCE OF FABRICATION METHODS ON MICROSTRUCTURE FAILURE

Single-crystal silicon microstructures, of identical design, exhibit d ifferent failure rates (following fabrication or mechanical shock test ing) due to various processes. The microstructures fabricated with a b oron diffusion and subsequent removal of the boron-diffused layer have a higher survival rate to the fabrication process and to mechanical s hock. The survival rate (a survivor has an intact proof mass and beam) through the process is increased by 26.5%. At a 3680g shock, the boro n-diffused devices have a 2.3% lower failure rate but the difference i s not statistically significant. These results have been developed wit h wafer-level shock testing, which permits bulk testing of many sample s in a cost-effective manner.