| 摘要 |
<p>[PROBLEMS] To provide a method for efficiently machining a work with a very short pulse. [MEANS FOR SOLVING PROBLEMS] The method is used for machining a work such as a board with a laser beam. The method is characterized in that a very short pulse laser beam having a wavelength to which the work is transparent is directed to the front surface of the work toward the back surface and focused, the beam waist of the focused laser beam is located away from the back surface of the work, a beam focus channel long in the light beam traveling direction from the beam waist formed by the auto-focusing action due to the laser beam propagation in the work is thus formed in the work, a substance in the channel is decomposed by the laser beam, the decomposed substance can be discharged from the back surface, and a cavity is formed in the channel. While forming the cavity, the laser beam is scanned, a machined surface is formed, and thereafter the work can be cut with a weak bending stress. The invention can be applied to divide two substrates opposed to each other, and can be used for dividing a glass substrate of a liquid crystal panel.</p> |
