We have developed an improved anisotropic wet etching process for the fabrication of various silicon microstructures with rounded concave and sharp convex corners, grooves for chip isolation, meandering micro-fluidic channels, mesa structures with bent V-grooves, and 45deg mirrors with highly smooth surface finish by using a single etching mask on (100) wafers. In this work, we use a CMOS compatible anisotropic etchant containing tetramethyl ammonium hydroxide (TMAH) and a small amount (0.1% v/v) of a non-ionic surfactant (NC-200), containing 100% polyoxyethylene-alkyl- phenyl-ether. The process has been developed by analyzing the etching characteristics of (100) silicon wafers in pure and surfactant added TMAH.