Surface micromachining of unfired ceramic sheets

Conventional surface micromachining techniques including photolithography and both wet and dry etching have been directly applied to an unfired sheet of yttria-stabilized zirconia ceramic material. Reversible bonding methods were investigated for affixing unfired ceramic samples to silicon handle wafers in order to perform photolithography. Three types of photoresist were investigated. Thin film photoresist allowed a line-width feature size of 8 μm to be obtained. Thick film photoresist exhibited a coverage gradient after being spun on. Chemical etching was successfully performed isotropically with concentrated hydrofluoric acid. A dry thick film resist applied by lamination provided coverage during plasma etching. Neither an oxygen plasma nor a mixture of sulfur hexafluoride and oxygen plasma proved successful at etching the unfired ceramic. Embossing was performed on the meso-scale with feature shrinkage of approximately 45% after sintering.