Photoplastic shadow-masks for rapid resistless multi-layer micropatterning

A rapid and simple fabrication method to construct tiny shadow-masks and their use in multi-layer surface patterning with in-situ micromechanical alignment is presented. Free-standing shadow-mask membranes are made of a 5-μm-thick SU-8 based resist layer by photolithography. They are supported by a 1-mm-large and 150-μm-thick SU-8 rim. The membrane has apertures with feature sizes ranging from 6-300 μm. Multiple layer deposition by electron beam evaporation of Cr, Au and Al through the membrane apertures results in aligned multilayer patterns. By using in-situ micromechanical alignment pins or jigs we achieved an overlay precision of < 2 μm in both, x and y direction. The resistless shadow mask deposition technique eliminates photolithography processes and allows surface patterns to be made in a rapid and vacuum-clean way on arbitrary millimeter-size surfaces, and at low-cost.