| 摘要 |
<p>In the present invention, laser light is focused onto a quartz-crystal workpiece from the top surface thereof so as to form a modified region along a planned-cut line near the roughened bottom surface of the workpiece, thereby preventing the formation of cracks exposed to the top surface of the workpiece and improving the post-cutting dimensional precision of the workpiece. Since the modified region (7) is formed near the bottom surface (21), there could be concern about damage to the bottom surface (21), but the high ablation threshold of quartz causes much of the energy of the laser light (L) to be used up forming the modified region (7) and the bottom surface (21) being roughened causes laser light (L) that reaches the bottom surface (21) to scatter, resulting in little damage to the bottom surface (21). The present invention thus makes it possible to cut a quartz-crystal workpiece (1) with high dimensional precision and prevent damage to the outer surfaces of said workpiece (1).</p> |
