LASER MICROMACHINING THROUGH A SACRIFICIAL PROTECTIVE MEMBER

摘要

A small feature at a target location (106) on a working surface (108) of a workpiece (110) is laser machined. A laser beam (104) propagating along a beam path is directed for incidence at the target location (106) on the working surface (108) to machine the small feature. A focusing lens (112) sized to converge the laser beam (104) on the working surface (108) is set in the beam path at a short working distance (x1) from the working surface (108) to laser machine the small feature and thereby eject target material from the workpiece back toward the focusing lens (112). A sacrificial protective member (114) positioned between the focusing lens (112) and the working surface (108) transmits without appreciable distortion or adsorption the laser beam (104) focused by the focusing lens (112) and incident on the working surface (108). The sacrificial protective member (114) intercepts the ejected target material to prevent a sufficient amount of it from reaching and thereby appreciably contaminating the focusing lens (112).