We present an oblique microstructure, a tetrahedral three-facet micro mirro
r, and its fabrication process with the inclined deep X-ray lithography (DX
RL). The mirror has an equilateral triangular base of 100 mum length and mi
rror-like three side-facets inclined to the base at 45 degrees with knife e
dges. When two equilateral triangle patterns of gold absorber in the X-ray
mask shade the PMMA (polymethylmethacrylate) substrate with two times of in
clined DXRL at angles of 45 degrees and tan(-1)(2)degrees, the shaded part
of PMMA produces a tetrahedral three-facet mirror. The process has been con
ducted with "a" X-ray mask without any alignments that may degrade the prec
ision of microstructures. The completed tetrahedral mirror shows excellent
aspects of mirror-like facets and knife-edges with a surface roughness of 2
0-30 nm. By changing the gap distance between the X-ray mask and the PMMA s
ubstrate, the size of the three-facet mirror can be controlled. The three-f
acet micro mirror is devised as a three-directional laser beam reflector fo
r the measurement of 6 d.f. motion of the slider flying on a magnetic disk
of a hard disk driver (HDD). (C) 2001 Elsevier Science B.V. All rights rese
rved.