단일 식각 홀을 갖는 SiO2 희생층의 불화수소 증기 식각

Abstract

This study experimentally verified the etch rate of the SiO2 sacrificial layer etching process with a single etch hole using vapor-phasehydrogen fluoride (VHF) etching. To fabricate small-sized polysilicon etch holes, both circular and triangular pattern masks wereemployed. Etch holes were fabricated in the polysilicon thin film on the SiO2 sacrificial layer, and VHF etching was performed to releasethe polysilicon thin film. The lateral etch rate was measured for varying etch hole sizes and sacrificial layer thicknesses. Based on the measuredresults, we obtained an approximate equation for the etch rate as a function of the etch hole size and sacrificial layer thickness. Theetch rates obtained in this study can be utilized to minimize structural damage caused by incomplete or excessive etching in sacrificiallayer processes. In addition, the results of this study provide insights for optimizing sacrificial layer etching and properly designing thesize and spacing of the etch holes. In the future, further research will be conducted to explore the formation of structures using chemicalvapor deposition (CVD) processes to simultaneously seal etch hole and prevent adhesion owing to polysilicon film vibration.