単結晶シリコンのスローツールサーボ旋削によるマイクロレンズアレイ加工

抄録

Microlens arrays of single-crystal silicon are required increasingly in advanced IR optics. In this study, we attempted to fabricate concave microlens arrays on a single-crystal silicon wafer by slow-tool-servo diamond turning. The form error, surface topography, material phase transformation and cutting force characteristics were investigated experimentally. It was found that brittle fracture occurred preferentially at one side (the exit side of tool feed) of the lens dimples when cutting direction is along <110> and tool feed rate is high. Amorphous silicon phase was generated significantly at the exit side of tool feed of the dimples as tool feed rate increased. The peak values of cutting forces changed with tool feed rate and crystal orientation. Spherical microlens arrays with a form error of ~300 nmPV and surface roughness of ~6 nmSa were successfully fabricated.