Method and apparatus for effecting selective ablation of a coating from a substrate, and controlling the wall angle of coating edge portions

摘要

The angles of the walls of vias being ablated by excimer lasers are controlled by interposing refractive elements between the masks and the workpieces, and rotating the refractive elements about axes parallel to the optical axis. In one embodiment, the refractive element has parallel faces, and is inclined. In another embodiment, the faces of the refractive element are at a small angle to each other.