Advanced bulk micromachining using aqueous pure and Triton X-100 [C 14H22O (C2H4O)n, n= 9-10] added 25 wt% tetramethylammonium hydroxide (TMAH) solutions is presented in order to extend the range of MEMS structures realized by wet etching. Fabrication processes include twostep wet etching, local oxidation of silicon (LOCOS), and silicon direct wafer bonding. A wide range of both fixed and freestanding MEMS structures are fabricated. The fixed structures such as rectangular and circular corrugations, square and circular shapes trays, etc. contain perfectly sharp edges and corners. The freestanding structures such as cantilever, microfluidic channels, etc. are fabricated using thermal oxide and single crystal silicon as materials.