Patent ID: 7388172
Filing Date: 2008-06-17
Classification: B23K,G03F

Abstract:
1. A method for forming an astigmatic focal beam spot to ablate and cut a substrate, said method comprising: determining a target energy density for said substrate; generating a raw laser beam; expanding said raw laser beam; modifying said expanded beam such that said modified beam is collimated in one principal meridian and converging in another principal meridian; focusing said modified beam to produce an astigmatic focal beam spot on said substrate, said astigmatic focal beam spot having an elongated shape with a focused axis having a first focal point and an astigmatic axis having a second focal point separate from said first focal point, said astigmatic focal beam spot having a length along said astigmatic axis and a width along said focused axis, the width being less than the length, wherein said astigmatic focal beam spot is modified and focused to provide an energy density on said substrate at the target energy density for said substrate; and moving said substrate in a cutting direction along said length of said astigmatic focal beam spot such that said astigmatic focal beam spot causes ablation of said substrate to obtain at least a partial cut in said substrate.