JPH01286147A - Development monitoring method - Google Patents

Abstract

PURPOSE:To monitor the progressive state of development in a radius direction by projecting a laser beam on the pattern plane of an optical master disk as scanning in the radius direction, and computing the strength ratio of obtained 0th-order and 1st-order diffracted light. CONSTITUTION:The laser beams (a1 to an) are projected on the rotating pattern plane of the master disk 1. The 0th-order and 1st-order diffracted light (b) and (c) are detected by detectors 4 and 5. The detectors move on a stage 6 in the radius direction synchronizing with the scan of the laser beam. The output voltage signals of the detectors 4 and 5 are supplied to a monitor 9 as 0th-order and 1st-order diffraction strength signals (f1 to fn) and (g1 to gn) via amplifiers, respectively. The monitor computes and outputs diffracted light ratio signals (h1 to hn). The drop of developer is shifted to an outer periphery when the ratio signal (h) of a pattern inner periphery is larger than that of a pattern outer periphery, and the progression of the development at the inner periphery is suppressed, thereby, uniform group width are formed at the inner and outer peripheries.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a development monitoring method, and particularly to a development monitoring method for monitoring the progress of development of an optical disc master.

[Conventional technology]

A conventional development monitoring method will be explained in detail with reference to the drawings.

In the development monitor device shown in FIG. 3, the O-th stylus tip and the 1st-th stylus are obtained by irradiating a laser beam a onto the pattern surface of an optical disk master fixed to a chuck table 2 and being developed while being rotated by a spindle 3. The needle base C is detected by a pair of detectors 4 and 5.

The voltage signals d and e of the detectors 4 and 5 are amplified by a pair of amplifiers 7.8 to become an O-th order needle base intensity signal f and a 1st-order diffracted light intensity signal g.

The diffracted light ratio monitor section calculates a diffracted light ratio g/f from the 0th-order diffracted light intensity signal f and the 1st-order diffracted light intensity signal g, and outputs it to the terminal 200 as a diffracted light ratio signal.

When the diffraction light ratio signal outputted to the terminal 200 reaches a desired diffraction light ratio, the dropping of the developer is stopped and the development is completed. Furthermore, it is known that there is a proportional relationship between the diffracted light ratio and the group width, and the group width at the monitor position can be made constant.

However, in actual exposure, there is a difference in the amount of exposure per unit area in the radial direction of the pattern, so a difference in group width occurs in areas other than the monitor radius.

Problems to be Solved by Invention C] However, in the above-described conventional development monitoring method, by irradiating a laser beam onto one point in the radial direction on the optical disc master, the 0th order obtained as development progresses. Since the structure is such that the diffracted light and the first-order diffracted light are optically strongly crystallized using a pair of detectors and amplifiers, the amount of exposure per unit area changes in the radial direction of the pattern on the optical disk master, resulting in a diffracted light ratio signal. There is a drawback that it is impossible to monitor the diffracted light ratio signal in the radial direction of the pattern even if the pattern changes.

[Means to solve the problem]

The development monitoring method of the present invention sequentially scans and irradiates the pattern surface of a rotating optical disk master with a laser beam in the radial direction, thereby monitoring the 0th-order diffracted light and the 1st-order diffracted light obtained from the pattern surface as development progresses. The diffracted light ratio is sequentially calculated from the O-order diffracted light intensity and the 1st-order diffracted light intensity detected by sequentially sampling the diffracted light with a pair of detectors that scan in accordance with the scanning of the laser beam. It is configured to monitor the development progress in the pattern radial direction from the diffracted light ratio signal.

〔Example〕

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

In the development monitoring device shown in FIG. 1, an optical disk master 1 is fixed to a chuck table 2 and rotated by a spindle 3. The laser beam is sequentially scanned in the radial direction of the optical disc master 1 (indicated by the arrow), and the laser beam a+
+ &2# a3. ~． afi is irradiated onto the pattern surface of the optical disc master 1.

Further, the zero-order diffraction beam is detected by the detector 4, and the first-order needle head C is detected by the detector 5, respectively. The detectors 4 and 5 sequentially scan the optical disk master 1 in a radial direction in accordance with the scanning of the laser beam from the movable stage 6.

Therefore, 0th needle base b l# b 2z b 3#
~,b, are detected by the detector 4 and the voltage signal dlnd!
.

Output as d3e~, d, primary needle point C1pC2
aC3, ~, C3 are detected by the detector 5 and the voltage signal e
1m e! +es, ~,e, are output.

The amplifier 7 amplifies the voltage signals dl+d2+dsz~, d to produce 0th-order diffracted light intensity signals fl, fz+fsa~.

The amplifier 8 outputs voltage signals e,,e! n6
3+~, e0 is amplified to obtain first-order diffracted light intensity signal g++g2
Output as ygs+~2g, .

The diffracted light ratio monitor section 9 receives the O-th needle base strength signal f l pf
z, fs*~, f,,! = 1st order diffracted light needle source signal g1s
The diffracted light ratio is calculated from gtrgss~2gd and is sent to the terminal 200 as a diffracted light ratio signal hl+ht+hss~,h.
is output to.

FIG. 2 is a graph showing the relationship between the diffraction light ratio signal output from the diffraction light ratio monitor section shown in FIG. When the exposure amount per unit area is constant, the diffracted light ratio signal of inner circumference γ2, middle circumference γ1, and outer circumference γ is constant and becomes hl at each position, and the straight line 20
However, when the exposure amount of the inner circumference γ1 is smaller than the exposure amount of the outer circumference γ, the line becomes a straight line 21, and when the exposure amount of the inner circumference γ1 is larger than the exposure amount of the outer circumference γ, the line becomes a straight line 22.

Therefore, the development monitoring method of the present invention is used to detect the diffraction light ratio signal in the radial direction of the pattern, and when the diffraction light ratio signal on the inner circumference of the pattern is larger than the diffraction light ratio signal on the outer circumference, for example, dropping of the developer is detected. By moving to the outer periphery and suppressing the development progress on the inner periphery of the pattern, if the diffraction light ratio signal on the inner periphery of the pattern is smaller than the diffraction light ratio signal on the outer periphery, for example, pure water is dropped on the outer periphery and the development process is suppressed. By suppressing the progress of development, it is possible to create uniform group widths on the inner and outer peripheries of the pattern.

〔Effect of the invention〕

The development monitoring method of the present invention scans the pattern surface of the optical disc master sequentially with a laser beam in the same radial direction, and sequentially detects the diffraction light ratio from the obtained 0th-order diffracted light and first-order diffracted light. When the exposure amount per unit area changes in the radial direction of the upper pattern, it is possible to monitor the change in the diffraction light ratio signal in the radial direction of the pattern.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a graph showing the relationship between the diffraction light ratio signal and pattern radius in the embodiment shown in Fig. 1, and Fig. 3 shows a conventional example. It is a block diagram. 1...Optical disc master, 2...Chuck table, 3...Spindle, 4, 5...
...detector, 6...movement stage, 7,8.
...Amplifier, 9...Diffraction light ratio monitor section,
20,21.22... Straight line, &, &l+
82. &2. ~． alto ""... Laser beam, b... 0th order diffracted light, C... 1st order diffracted light, d. e...Voltage signal, f...0th order diffraction light intensity signal, g...1st order diffraction light intensity signal, h, hl
...... Diffraction light ratio signal, γ, γ1. γ2. γ3...
····radius. Agent Patent Attorney Uchihara Otohia Figure 2: Sheep rash -

Claims (1)

[Claims] A laser beam is sequentially scanned and irradiated onto the patterned surface of a rotating optical disc master in the radial direction, and as development progresses, the 0th-order diffracted light and the 1st-order diffracted light obtained from the patterned surface are integrated into the scanning of the laser beam. The diffracted light ratio is sequentially calculated from the detected 0th-order diffracted light intensity and the 1st-order diffracted light intensity, and the development progress in the radial direction of the pattern is determined from the obtained diffracted light ratio signal. A method for monitoring development.