| 摘要 |
PROBLEM TO BE SOLVED: To perform control so that the surface of a master disk is positioned near the focus of an objective lens as initial setting when the resist of the master disk is exposed. SOLUTION: An objective lens 62 is vibrated in a Z direction by a sine wave of amplitude 10μm and a frequency 200Hz. When a master disk 61 is moved at a speed of 1 mm/sec., a primary straight line indicating the displacement of the master disk 61 and the displacement of the sine wave intersect each other at a plurality of spots. By monitoring the sum signal of a photodetector, a sum signal is generated in the intersecting period, and the possibility of detecting positioning is increased as compared with a method for not vibrating the objective lens 62. When the sum signal of the photodetector is detected, the z-direction movement of the master disk 61 is stopped to finish a positioning sequence. Then, a focus servo is turned on. COPYRIGHT: (C)2007,JPO&INPIT
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