Microfabrication processes on cylindrical substrates – Part II: Lithography and connections

Cylindrical microfabrication offers the opportunity to fabricate electrical or mechanical devices around the surfaces of cylinders. Standard processes developed for planar substrates such as silicon wafers must be adapted to curved surfaces. This paper focuses on lithography of and connections to cylinders. Results from lithographic testing includes dose exposure curves using laser and electron beam sources as well as the minimal effects of surface curvature on linewidth. Bonding included ultrasonic wedge bonding, silver epoxy, and solder paste. Electrical and mechanical characteristics of these bonding methods are presented.