Fabrication of the 3 Dimension Resist Microstructure Using X-Ray Diffraction and Applying to LIGA Process

Abstract

The LIGA process consists of lithography, electroforming and molding has attracted attention in microstructure fabrication techniques. At the molding process of LIGA process, it is difficult to pull out from the mold that is assumed especially in the case of high aspect ratio structures. However, release from mold is improved by tapered structure. In this research, we have proposed a method for achieving tapered structure using the diffraction exposure technique which makes use of diffraction phenomenon. Diffraction is caused by providing a clearance between a resist structure and an X-ray mask. The fabricated structure was the lines and intermediate space whose processed depth was 200 µm and designated the taper angle of 5 degrees as set point. The variable parameters were the slit width, the X-ray dose and the gap between the X-ray mask and the resist structure. It is controlled that discovering the conditions for taper angle 5 degrees and inspecting the relationship between a taper angle and a mold releasability by electroforming and the molding of the LIGA process. We have fabricated the mold with taper angle of 2.5 degrees by electroforming. The Ni mold could partially copy the master pattern well.