The Application of Diamond-based Electrodes for Efficient EDMing of Silicon Wafers for Freeform MEMS Device Fabrication

Using EDM technology in conjunction with traditional MEMS fabrication techniques offers great advantages in the creation of freeform features silicon wafers. The ability to mass produce features, however, is often limited by high electrode wear rates due to poor EDMing stability based on silicon's material properties. By investigating the use of novel diamond-based electrode materials, high productivity and low wear rates can be achieved simultaneously. First, the feasibility of applying diamond-based electrodes is presented through the rough EDMing of 200 hemispherical features. Second a two-step EDM roughing and finishing process is applied in order to achieve high quality and axisymmetric hemispherical features. Using only an EDM roughing process, 200 hemispherical features were successfully fabricated in 80 minutes with virtually zero electrode end wear. The two-step EDM roughing and finishing process resulted in the fabrication of 15 highly axisymmetric hemispherical features with only 15 microns of total electrode end wear. A case study is presented in the fabrication of hemispherical shell structures, where the EDMed hemispherical features are used as a mold for MEMS device fabrication.