Invar electrodeposition for MEMS application

Low thermal expansion metal such as Invar is suitable for MEMS application, where the dimension stability requirement is very high over a wide temperature range. Invar electrodeposition process was developed as a method to fabricate Invar structure. The effect of plating parameters were investigated to develop optimized Invar deposition process. The Invar film obtained in this research has the thermal coefficient of expansion as low as 6.3 PPM/K, which is almost half of that of pure nickel. The process compatibility to the rest of MEMS fabrication process was proved through the prototyping of a microstructure.