Cylindrical film deposition system for three-dimensional titanium–nickel shape memory alloy microstructure

We have designed and developed a sputtering deposition apparatus to fabricate a cylindrical spring-like microstructure for a titanium–nickel (Ti–Ni) shape memory alloy (SMA) film-actuated micro-catheter. The developed apparatus that mainly consists of gearboxes to transform rotation of a stage into rotation of a shaft specimen is mounted on a ternary-source sputtering system. By using this system, a Ti–Ni SMA film with the controlled composition has been successfully deposited around a copper (Cu) shaft surface and the annealed film has possessed the shape memory characteristics evaluated by X-ray diffraction (XRD). A spring shape of the film has been capably patterned by photolithography and wet etching, so the developed deposition apparatus with a specimen rotation unit would be useful for fabricating a three-dimensional (3D) microstructure towards the active micro-catheter.