| 摘要 |
A laser processing method is provided for highly accurately cutting a board and a stacked part, even when the board whereupon the stacked part including a plurality of functional elements is formed is thick. In the laser processing method, a laser beam L is projected, having a rear plane (21) as a laser beam incidence plane, with a light collecting point P inside of a board (4), and modified areas (71, 72, 73) are formed inside the board (4). At this time, an HC modified area (73) is formed at a position between a cutting modified area (72) closest to the rear plane (21) and the rear plane (21), and a crack (24) along a cut planned line is generated from the HC modified area (73) to the rear plane (21). Thus, when an expand tape is adhered on the rear plane (21) of the board (4) and expanded, the crack smoothly advances from the board (4) to a stacked part (16) through the cutting modified area (72). As a result, the board (4) and the stacked part (16) can be accurately cut along the cut planned line. ® KIPO & WIPO 2007 |
