LASER PROCESSING METHOD AND SEMICONDUCTOR DEVICE

摘要

A laser processing method which can reliably form a modified region within an object to be processed along a desirable part in a line to cut is provided. This laser processing method irradiates a substrate 4 with laser light L while locating a light-converging point P within the substrate 4, so as to form a quality modified region 71 to become a starting point region for cutting within the substrate 4 along a line to cut 5. Here, the laser light L is oscillated pulsewise along a desirable part RP in the line to cut 5, and continuously in a predetermined part RC in the line to cut 5. Consequently, the quality modified region 71 is formed within the substrate 4 along the desirable part RP in the line to cut 5, whereas no quality modified region 71 is formed within the substrate 4 along the predetermined part RC in the line to cut 5.