Patent ID: 7709768
Filing Date: 2010-05-04
Classification: B23K,G03F

Abstract:
1. A method for scribing a semiconductor wafer using a laser, said method comprising: generating a laser beam; forming at least one astigmatic focal beam spot by modifying said laser beam such that said modified beam has two separate focal points and said astigmatic focal beam spot has an elongated shape, wherein forming said astigmatic beam spot uses a beam focusing lens to focus said modified beam such that one of said focal points is shorter than a nominal focal length of said beam focusing lens and the other of said focal points is formed generally at said nominal focal length of said beam focusing lens; directing said astigmatic focal beam spot at a surface of said semiconductor wafer, wherein said astigmatic focal beam spot is applied with a set of processing parameters such that said astigmatic focal beam spot causes ablation of said substrate to obtain at least a partial cut in said semiconductor wafer; moving said semiconductor wafer in a cutting direction along a length of said astigmatic focal beam spot to make at least a partial cut along at least one line in a first direction on said semiconductor wafer; rotating said semiconductor wafer about 90 degrees; and moving said semiconductor wafer in a cutting direction along a length of said astigmatic focal beam spot to make at least a partial cut along at least one line in a second direction orthogonal to the first direction on said semiconductor wafer.