LOW-THERMAL EXPANSION CERAMICS, THEIR PRODUCTION AND PART FOR PRODUCING SEMICONDUCTOR

摘要

PROBLEM TO BE SOLVED: To produce low-thermal expansion ceramics having a low thermal expansion and a high rigidity and to provide a method for producing the ceramics. SOLUTION: The low-thermal expansion ceramics are obtained baking a compact prepared by compounding 30-90 wt.% cordierite powder with 10-70 wt.% one selected from silicon nitride, silicon carbide and silicon oxynitride or a compact obtained by adding 0.1-10 wt.% yttria or a rare earth oxide and/or a lithium compound thereto in a vacuum or an inert gas atmosphere at 1,200-1,500 deg.C temperature. The ceramics have <=1×10<-6> / deg.C thermal expansion coefficient at 10-40 deg.C and >=150 GPa Young's modulus. The low-thermal expansion ceramics are applied to a part for producing semiconductors such as a stage for an exposure device to thereby enhance the accuracy in forming a highly fine circuit and raise the quality and mass productivity.