Large area and uniform polycrystalline diamond (poly-C) thin films, with a thickness of approximately 1 mu m, were grown and patterned on 4 in. oxidized Si wafers using IC compatible processes for microsystems applications. Uniform and reproducible seeding with a density of 2 X 10(10)/cm(2) was achieved by spinning diamond powder loaded water on 4 in. wafers. Gas mixture of 1.5% methane in hydrogen was used in MPCVD system for diamond film growth with optimized pressure and microwave power. Thickness variation of less than 20% was achieved on the 4 in. area using 43 Torr pressure and 2.8 kW microwave power. Electron cyclotron resonance (ECR)-assisted microwave plasma reactive ion etch was carried out using SF6/O-2/Ar gases to pattern the diamond films with an etch rate around 80 nm/min and less than 10% variation in etch rate over a 4 in. area. (c) 2005 American Vacuum Society.