| 摘要 |
A wafer has a device area where a plurality of devices are formed, and a peripheral marginal area surrounding the device area. These devices are formed on the front side of the wafer so as to be partitioned by a plurality of division lines. A modified layer is formed by applying a laser beam along the division lines with the focal point of the laser beam set inside the wafer, thereby forming a modified layer as a division start point inside the wafer along each division line. The wafer is transported to a position where the next step is to be performed. In the modified layer forming step, the modified layer is not formed in the peripheral marginal area of the wafer to thereby form a reinforcing portion in the peripheral marginal area. Accordingly, breakage of the wafer from the modified layer in the transporting step can be prevented. |
