JPH02304748A - Master disk exposing device for optical disk - Google Patents

Abstract

PURPOSE:To eliminate fluctuation in the intensity of exposure beam on a photoresist substrate and to enable exposure by the desired intensity of the exposure beam by detecting the exposure beam by an optical sensor provided on a moving optical system, monitoring and controlling the exposing quantity of head emission. CONSTITUTION:An exposing quantity detection part 12 on a moving optical system A receives exposing quantity monitor beam 11 reflected according to the reflection factor of a photoresist substrate 1. A detected exposing quantity correction part 16 divides an exposing quantity detection signal (c) by a reflection factor monitor signal (d) and calculates the detected exposing quantity when the reflection factor is 1. Then, the calculated quantity is outputted as a corrected detected exposing quantity signal (e). An optical modulator driving part 5 adjusts to outputs an optical modulator driving signal (f) so that an exposing quantity setting signal (b) can be coincident with the corrected detected exposing quantity signal (e). Then, an optical modulator 6 is driven and the intensity of laser beam 3 is adjusted. Thus, there is no fluctuation in the intensity of an exposure beam 7, with which the surface of the photoresist substrate 1 is irradiated, and the exposure can be executed by the desired intensity of the expo sure beam 7.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical disk master exposure apparatus.

[Conventional technology]

In conventional optical disk master exposure apparatuses, in order to control the power of the exposure beam, it is common to sample the beam on a fixed optical system and monitor this to control the optical modulator.

FIG. 2 is a block diagram showing a conventional example.

The optical disk master exposure apparatus shown in FIG. 2 detects the distance between the rotation center axis of the rotating photoresist substrate 1 and the center axis of the head lens 10 on the moving optical system A', and outputs a head position detection signal a. a head position detection section 17; an exposure amount setting section 4 in which the exposure beam intensity for the head position detection signal a is preset as an exposure amount setting signal;
An optical modulator 6 for adjusting the intensity of the laser beam 3 emitted from the laser oscillator 2, and a monitor sample obtained by sampling the beam emitted from the optical modulator 6 with a beam sampler 18 on a fixed optical system B'. The optical sensor section 19 on the fixed optical system B' which detects the beam 20 and outputs the optical sensor output signal g, and the optical modulator drive signal are applied so that the exposure amount setting signal and the optical sensor output signal g match. The optical modulator driving section 5 adjusts f and drives the optical modulator 6.

During exposure, the head position detection unit 17 detects the distance between the rotation center axis of the rotating photoresist substrate 1 and the center axis of the head lens 10.

The exposure amount setting section 4 outputs an exposure amount setting signal S in response to the head position detection signal a. The intensity of the laser beam 3 emitted from the laser oscillator 2 is adjusted by the optical modulator 6, and the optical sensor unit 19 on the fixed optical system B' converts the beam emitted from the optical modulator 6 into the fixed optical system B'. The monitor beam 20 sampled by the beam sampler 18 above is detected.

The light modulator drive section 5 adjusts and outputs the light modulator drive signal f so that the exposure amount setting signal matches the photosensor output signal g, drives the light modulator 6, and adjusts the intensity of the laser beam 30. Adjust.

The exposure beam 7 whose intensity has been adjusted by the optical modulator 6 is bent by the beam splitter 9 on the moving optical system A', passes through the head lens 10, and is irradiated onto the photoresist substrate 1 for exposure.

[Problem to be solved by the invention]

However, in the above-mentioned conventional optical disk master exposure apparatus, the output beam of the optical modulator is monitored on a fixed optical system and the intensity of the exposure beam is adjusted, so it is difficult to align the fixed optical system and the moving optical system. Due to the deviation of
Beam sampler? The intensity of the exposure beam that is actually irradiated onto the photoresist substrate may vary due to deviations in the incidence on each optical element of the optical system or changes in the state of each optical element, and the intensity of the exposure beam actually irradiated onto the photoresist substrate may vary. It has the disadvantage that it cannot be exposed to light at different intensities.

[Means to solve the problem]

The optical disk master exposure apparatus of the present invention is an optical disk master exposure apparatus in which an optical system including a head for focusing at least a laser beam for exposure onto a photoresist substrate is constructed as a moving optical system. an exposure amount detection unit that detects the exposure beam on the moving optical system; a reflectance monitor unit that detects the focusing laser beam reflected by the photoresist substrate on the moving optical system; an exposure amount correction section that corrects the exposure amount detection signal obtained from the exposure amount detection section using the obtained reflectance monitor signal; an exposure amount setting section that is set in advance in accordance with the position of the head; and the exposure amount setting section. and a modulator drive section that controls the optical modulator so that the exposure amount setting signal obtained from the detection exposure amount correction section matches the corrected detected exposure amount signal obtained from the detected exposure amount correction section.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

The optical disk master exposure apparatus shown in FIG. 1 includes a head position detection section 17 that detects the distance between the rotation center axis of the rotating photoresist substrate 1 and the center axis of the head lens 10 and outputs a head position detection signal a; an exposure amount setting unit 4 in which the intensity of the exposure beam with respect to the head position detection signal a is already set in advance by an exposure amount setting signal; an optical modulator 6 that adjusts the intensity of the laser beam 3 emitted from the laser oscillator 2; The exposure beam 7 emitted from the optical modulator 6 is bent by the beam splitter 9, transmitted through the head lens 10, and reflected by the photoresist substrate 1 as an exposure monitor beam 11.
A focus laser beam 8 is reflected by the photoresist substrate 1 and a reflectance monitoring beam 14 taken out by a dichroic mirror 13 is detected by the moving optical system A. The reflectance monitor section 15 detects the reflectance, and the reflectance monitor signal d obtained from the reflectance monitor section 15 corrects the exposure detection signal C obtained from the exposure detection section 12 to obtain a corrected detected exposure signal e. an optical modulator that adjusts the optical modulator drive signal f so that the detected exposure amount correction unit 16 outputs the detected exposure amount signal e matches the exposure amount setting signal and the corrected detected exposure amount signal e, and drives the optical modulator 6; Drive part 5
It consists of:

During exposure, the head position detection unit 17 detects the distance between the rotation center axis of the rotating photoresist substrate 1 and the center axis of the head lens 10 .

The exposure amount setting section 4 outputs an exposure amount setting signal S corresponding to the head position detection signal a. At this time, the exposure amount setting signal is based on the assumption that the beam reflectance on the photoresist substrate 1 is 1.

A laser beam 3 emitted from a laser oscillator 2 has its intensity adjusted by an optical modulator 6, becomes an exposure beam 7, is bent by a beam splitter 9 on a moving optical system A, is transmitted through a head lens 10, and is a photo beam. The resist substrate 1 is irradiated.

The exposure amount detection unit 12 on the moving optical system A receives the exposure amount monitor beam 11 reflected according to the reflectance of the photoresist substrate 1.

Further, the focusing laser beam 8 is connected to the head lens 1
0 and is irradiated onto the photoresist substrate 1. The reflectance monitor unit 15 on the moving optical system A receives the reflectance monitoring beam 14 that is reflected according to the reflectance of the photoresist substrate 1 and taken out by the dichroic mirror 13, and calculates the reflectance of the photoresist substrate 1. and output.

The detected exposure amount correction section 16 divides the exposure amount detection signal C by the reflectance monitor signal d, calculates the detected exposure amount when the reflectance is 1, and outputs it as a corrected detected exposure amount signal e.

The optical modulator driving section 5 adjusts and outputs the optical modulator driving signal f so that the exposure amount setting signal and the corrected detected exposure amount signal e match, drives the optical modulator 6, and outputs the optical modulator driving signal f. Adjust the intensity of beam 3.

〔Effect of the invention〕

The optical disk master exposure apparatus of the present invention detects the exposure beam reflected from the photoresist substrate during exposure using an optical sensor provided on a moving optical system, and monitors and controls the exposure amount emitted from the head. This has the effect of eliminating fluctuations in the intensity of the exposure beam on the photoresist substrate due to misalignment or changes in the state of the optical element, and making it possible to perform exposure with a desired exposure beam intensity.

Also, at this time, a part of the focusing beam reflected from the photoresist substrate is detected as a reflectance monitoring beam by an optical sensor provided on the moving optical system, and the reflectance of the photoresist substrate is calculated. By subtracting the exposure beam intensity reflected from the photoresist substrate, variations in the exposure beam intensity due to variations in reflectance of the photoresist substrate due to photoresist film thickness, etc. are eliminated, and the exposure amount emitted from the head can be reduced. It also has the effect of allowing accurate monitoring.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. 1... Photoresist substrate, 2... Laser oscillator, 3... Laser beam, 4...
...Exposure amount setting unit, 5...Light modulator drive unit, 6
......Light modulator, 7...Exposure beam, 8
...Focusing laser beam, 9...
・Beam splitter, 10...Head lens,
11... Exposure monitor beam, 12...
・Exposure amount detection unit, 13... Dichroic mirror, 14... Reflectance monitor beam, 15...
...Reflectance monitor section, 16...Detected exposure amount correction section, 17...Head position f detection section, 18...Beam V amplifier, 19...
... Optical sensor section, 20 ... Monitoring beam,
a...head position detection signal, b...exposure setting signal, C...exposure detection signal, d...
...Reflectance monitor signal, e...Correction detection exposure amount signal, f...Light modulator drive signal, g...
... Optical sensor output signal, A, A'... Moving optical system, B, B'... Fixed optical system.

Claims (1)

[Claims] an exposure amount detection unit that focuses an exposure laser beam onto at least the photoresist substrate and detects the exposure beam reflected by the photoresist substrate on a moving optical system; and a focusing laser beam reflected by the photoresist substrate. a reflectance monitor section that detects the beam on the moving optical system; and a detected exposure amount correction section that corrects the exposure amount detection signal obtained from the exposure amount detection section using the reflectance monitor signal obtained from the reflectance monitor section. , an exposure amount setting section that is set in advance in accordance with the position of the head, and an exposure amount setting signal obtained from the exposure amount setting section and a corrected detected exposure amount signal obtained from the detected exposure amount correction section. 1. An optical disk master exposure apparatus comprising: a modulator drive unit that controls an optical modulator.