ABSTRACT
This chapter discusses the fabrication methods of convex corners on and silicon wafers using silicon bulk micromachining based on anisotropic wet chemical etching. In wet anisotropic etching–based bulk micromachining, stable etched profiles are shaped by slowest-etch-rate planes. To realize well-defined convex corners in the wet bulk micromachining process, corner compensation is a most popular method. In the fabrication of wet-bulk-micromachined structures, undercutting at convex corners plays a significant role. It has its own advantages and disadvantages in the fabrication process. In the case of a concave corner, regardless of its shape, the concave ridge consists of atoms with no dangling bonds. The dimensions of the compensating structures depend on the etch depth up to which the convex corners have to be created. This technique, therefore, requires precise control of the etch rate and highly uniform wafer thickness.
