Engineering design guide for etch holes to compensate spring width loss for reliable resonant frequencies

This paper describes design guidance for a compensation method of spring width loss during silicon deep RIE (reactive ion etch) process. We found that a compensation factor (CF), defined by circumference (C) of unit etch hole divided by its area (A), is directly related to the variation of resonant frequencies of silicon MEMS resonators. We proposed 5 models with different etch hole shapes and investigated the effect of etch holes on resonant frequencies. The model with proposed etch holes showed three fold smaller variation of resonant frequencies than other models with conventional etch holes.