The Electrochemical Micromachining of Microactuator Devices from Sputtered NiTi Thin Films

Spring 1997

Dr. D.M. Allen and T.T. Chen, Cranfield University

This paper describes the manufacture of minia­ture cantilevers from free-standing, 10 µm thick sputtered NiTi SMA films and double-beam de­vices from similar films deposited on alumina, coated with sputtered noble metal, using the technique of electrochemical micromachining. This technique employes standard photoresist processing but with dissolution of the alloy achieved by an anodic process in an electrolytic cell using a non-aqueous electrolyte of 5% sulphuric acid in methanol to etch the devices. .The etch rate depends directly on the anodic cur­rent density but the problem of determining the exact etching time to achieve a vertical edge pro­file on the devices still presents a challenge.