Focused Ion Beam Machining of Precision Die for Micro Optical Lens Molding

Abstract

Glass-like carbons (GCs) for press molding die of micro optical glass lens and electroless Ni-P alloy films for injection molding die of micro optical plastic lens were machined by focused ion beam (FIB) and their dimensional accuracy, surface roughness and transcriptional performance were investigated. The GCs completed a fine surface roughness of Ra=1nm after FIB machining, although their FIB etching rate was decreased to a half rate of Si(100) single crystal. On the other hand, amorphous Ni-P alloy films containing phosphorus more than 7wt% possessed higher etching rate than Si(100) crystal, as well as fine surface roughness less than 8nm. Precision GCs and Ni-P alloy films molding dies with 3-D microlens array of 7μm square were fabricated by FIB. Subsequently, transcriptional performance to micro optical lens was evaluated on precision GC dies.