PRODUCTION OF MASTER DISK WITH OPTICAL DISK GROOVE

摘要

PURPOSE:To form the even groove width between inner and outer circumferences of a substrate by performing the exposure with control to satisfy the prescribed conditions according to the positions on a master disk during revolutions of a resist master disk applied with the photoresist. CONSTITUTION:A glass substrate 1 applied with the photoresist is revolved by a spindle motor 2 and also shifted in its radius direction by a feed motor 3. The light delivered from a laser light source 4 is modulated by an optical modulator 5 with an input signal 6 and forms a spot on a resist film of the substrate 1 via a mirror 7 and an objective lens 8. The laser light is turned on and off with the signal 6 applied to the modulator 5. At the same time, the exposure power is controlled by the signal voltage. The laser power P2 which exposes an optional distance R2 from the center of an exposure zone is defined as P2=P1(2+3R2/ R1)/5, where P1 is the power needed for exposure of the exposure zone at a distance R1 between the center and an inner circumference of a resist master disk 1. Thus the even groove width is obtained.