Silicon as a plastic material

Abstract

Plastic reshaping is applied to different Si microelements. Because of the brittleness of Si at room temperature the process is performed at 900 °C. Microelements suitable for plastic reshaping are beams fastened at one side, stripes fastened at two sides, membranes and bars. Microelements were integrated into one wafer and fabricated by wet anisotropic etching. After this, in a testing machine equipped with a furnace, the reshaping process was carried out in different ways: (1) loading of elements in single chips with a silica rod or special tools and (2) simultaneous loading of all elements in the wafer (batch process) with special wafer tools. The tools (a stamp and a rest) were also fabricated by wet anisotropic etching. Using these tools very exact deformed shapes can be made, but the bend is limited by the depth/height of the tools. Very large bends can be realized by using the silica rod, but the exact positioning is difficult. Planned applications are a micro mirror with a slope of 45° to the wafer plane, a clip-system and a guide through several wafers.