Large area and uniform polycrystalline diamond (poly-C) thin films, with a thickness of approximately 1μm, were grown and patterned on 4in. oxidized Si wafers using IC compatible processes for microsystems applications. Uniform and reproducible seeding with a density of 2×1010/cm2 was achieved by spinning diamond powder loaded water on 4in. 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 4in. area using 43Torr pressure and 2.8kW microwave power. Electron cyclotron resonance (ECR)-assisted microwave plasma reactive ion etch was carried out using SF6/O2/Ar gases to pattern the diamond films with an etch rate around 80nm/min and less than 10% variation in etch rate over a 4in. area.