A novel convex corner compensation for wet anisotropic etching on (100) silicon wafer

In general, the convex corner structure and the non {111} crystal planes will be undercut during the wet anisotropic etching. This characteristic has been extensively exploited to fabricate free suspended thin film structures. On the other hand, these effects have to be reduced or prevented in various applications. This study has successfully demonstrated a technique to prevent the convex corner and non {111} crystal planes from undercut. Thus, the process to employ the characteristic of DRIE to assist the wet anisotropic etching becomes available. In applications, the experimental results show that the mesas and cavities with arbitrary shapes can be fabricated using wet anisotropic etching. Moreover, these mesas and cavities can further integrate with suspended thin film structures and the structure formed by the inclined {111} crystal planes. Hence, the variety of bulk micromachined MEMS devices will significantly increased.