| 摘要 |
<p>PURPOSE:To machine the photomask to desired depth by using a converged ion beam without decreasing the light transmissivity of the mask substrate. CONSTITUTION:After a mask substrate 1 after being etched selectively with a converged ion beam 2, an ion penetrating layer 4 which is formed by the process is irradiated with a laser beam 3 and thermally vaporized and at this time, the depth of the FIB etching is set to the value obtained by subtracting the thickness (d) of the ion penetrating layer 4 from the desired etching depth D.</p> |
