| 摘要 |
An identification mark formation method for forming an identification mark on a refractory material single crystal substrate that is made of one selected from the group consisting of sapphire, gallium nitride, aluminum nitride, diamond, boron nitride, zinc oxide, gallium oxide, and titanium dioxide is disclosed. The method includes: (a) scanning a principal surface of the refractory material single crystal substrate with a laser beam at a first energy density such that a groove is formed in the principal surface of the refractory material single crystal substrate, thereby forming an identification mark in the principal surface of the refractory material single crystal substrate; and (b) scanning an inside of the groove of the refractory material single crystal substrate with a laser beam at a second energy density that is lower than the first energy density. |
