Fabrication techniques and their application to produce novel micromachined structures and devices using excimer laser projection

摘要

New techniques for 3D micromachining by direct laser ablation of materials using excimer lasers have been developed. Basic to all of these techniques is the use of image projection in which the laser is used to illuminate an appropriate pattern on a chrome-on-quartz mask. The mask is then imaged by a high-resolution lens onto the sample. Non-repeating patterns with areas of up to 150 × 150mm can be machined with sub-micron resolution and total accuracies of the order of a few microns by using synchronized scanning of the mask and workpiece. A combination of synchronized mask scanning and mask dragging techniques (in which the mask is held stationary and the workpiece moved during laser firing) enables patterns of up to 400 × 400mm to be produced; the limiting feature being the travel and accuracy of the precision air-bearing stages used to support the workpiece. This talk describes the synchronized mask scanning and mask dragging techniques and illustrates their application by presenting details of novel micromachined structures and devices so produced. These include rapid prototyping of bio-processor chips, fabrication of mechanical anti-reflection structures in CsI infra-red optical material, patterning films as frequency selective reflecting structures, Laser-LIGA and high aspect ratio machining using lamination techniques to produce an optical methane detector.