Complex microstructure fabrication by integrating silicon anisotropic etching and UV-LIGA technology

A fabrication method which integrates silicon anisotropic etching micromachining with UV-LIGA technology to make complex microstmetures is presented. This proposed combined process enables the fabrication of high-aspect-ratio and three-dimensional （3D） microstructures, which cannot be fabricated by silicon bulk mieromachining or UV-LIGA alone. To demonstrate this combined method, the 100μm thick SU-8 micro gears were fabricated on the silicon convex square structure, which is 100μm × 100μm× 80μm in dimension. In the subsequent micro hot embossing process, a novel type of plastics polyethylene terephtalate glycol （PETG） was tried for use. Through optimizing process parameters, PETG shows the potential of being used as plastic replica in micro-electro-mechanical system （MEMS）. This fabrication technology provides a new option for the increasing need of functionality, quality and economy of MEMS.