Fabrication of smooth thin diamond-like carbon microstructures by photolithography together with dry and wet etching techniques

Diamond-like carbon (DLC) films produced by the filtered cathodic vacuum arc (FCVA) technique have attracted considerable interest over the last few years, due to their excellent mechanical electronic, optical and tribological properties in addition to the smooth surface morphology. However, the utilization of DLC films in MEMS application has so far been limited due to the high compressive stress induced during growth. The large intrinsic compressive stress in the films causes the structure to curl up. By making use of substrate pulse bias of 1kV, the stress in the film has been lowered to 1.3GPa. Thin (∼150nm) diamond-like carbon cantilever microstructures were fabricated in this film by photolithography together with dry (reactive ion etching (RIE)) and anisotropic wet etching techniques. The problems associated with lithography, etching and processing of the microstructure are discussed in detail, in addition to the characterization of the films such as stress, surface morphology and microstructure.