JPH01286142A - Development monitoring method - Google Patents

Abstract

PURPOSE:To make correction due to difference in the characteristics of detectors unnecessary and to accurately perform the monitoring of development by detecting 0th-order diffracted light and 1st-order diffracted light obtained according to the progress of the development by one detector. CONSTITUTION:An optical master disk 1 is held on a chuck table 2, and spin development is applied on it by a spindle 3. A group is formed on the pattern plane of the master disk 1 according to the progress of the development, and the 0th-order diffracted light (b) and the 1st-order diffracted light (c) can be obtained by projecting a laser beam (a). The diffracted light (b) and (c) are made incident on the same detector 7 under the control of a detection control part 4 via shutters 5 and 6 which open and close alternately, and a diffracted light ratio (k) is operated at a diffracted light ratio monitoring part 9. By monitoring the diffracted light ratio (k), it is possible to monitor the progressive state of the development accurately without being affected by the sensitivity characteristic of the detector 7 or the change of the characteristic according to the offset of an amplifier 8, the difference and deterioration in gain characteristics.

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]

The conventional development monitoring method uses a development monitoring device as shown in FIG.
The laser beam a is irradiated perpendicularly to the pattern surface of the optical disk master 1 which is being spin-developed by the spindle 3, and the 0th order diffracted light obtained by irradiating this laser beam perpendicularly to the pattern surface, and the 1st order needle head C. , a detector 7a that detects the intensity of the 0th-order diffracted light beam, a detector 7b that detects the intensity of the 1st-order needle head C, and a voltage signal g0 of the detector 7& is amplified to obtain an O-th order needlepoint intensity signal. Amplifier 8 with h0
a and the voltage signal g of the detector 7b.

An amplifier 8b amplifies the signal to obtain a first-order diffracted light intensity signal h+, and calculates a diffracted light ratio h+/ho from the diffracted light intensity signal h0 and the first-order diffracted light intensity signal h+, and outputs the diffracted light ratio signal to a terminal. It is constructed using the diffracted light ratio detection section 10 which is outputted at 200.

Therefore, when the development start time is set to 0, the diffracted light ratio at the development time t is h l (t)/h 6 (t).

The developing device monitors the diffraction light ratio signal outputted to the terminal 200, for example, =h+(t)/ho(t), and when the desired diffraction light ratio is reached, stops dripping the developer and completes the development. . Furthermore, it is generally known that there is a proportional relationship between the group width during development and the diffracted light ratio, and development can be controlled by controlling the diffracted light ratio.

[Problem to be solved by the invention]

However, the conventional development monitoring method described above is configured to detect the light intensity of the 0th-order diffracted light and the 1st-order diffracted light obtained as development progresses using separate detectors and amplifiers. The adjustment to compensate for the difference in sensitivity characteristics between the two detectors and the difference in offset and gain characteristics between the two amplifiers is complicated, and the diffracted light ratio also changes due to changes in characteristics due to deterioration of the two detectors and amplifiers. There is a drawback that accurate development monitoring cannot be performed because of changes.

[Means to solve the problem]

The development monitoring method of the present invention uses one detector to detect the O-th order needle tip and the first-order diffracted light among the diffracted lights obtained as development progresses by irradiating a laser beam perpendicularly to the pattern surface of the optical disc master. The diffracted light ratio is calculated from the time series of the 0th-order diffracted light intensity and the time series of the 1st-order and needle tip intensities, which are obtained by alternately sampling the diffracted light ratio, and the progress of development is monitored using the time series of the diffracted light ratio. It is composed of

〔Example〕

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

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

In the development monitoring device shown in FIG. 1, an optical disc master l is held by a chuck table 2 and spun by a spindle 3. By irradiating the laser beam a perpendicularly to the pattern surface of the optical disk master 1, groups are formed on the pattern surface of the optical disk master 1 as the development progresses, so that the obtained needle tip is The primary needle points C are respectively incident on the detector 7 via the shutter 6.

The detector 7 detects the intensity of the diffracted light and outputs it as a voltage signal g, which is sent to the amplifier 8 as a diffracted light intensity signal and becomes an input signal to the diffracted light ratio monitor section 9.

Further, the detection control section 4 outputs the 0N10FF signal e to the shutter 5 and the inverted signal f of the 0N10FF signal e to the shutter 6 in response to the start signal d applied to the terminal 100.

When an ON signal is output to the shutter 5 as a 0N10FF signal e, and an OFF signal is output to the shutter 6 as a 0N10FF signal f, the detector 7 detects the 0th order diffracted light beam, and the voltage signal g0
It is outputted as , amplified by the amplifier 8 and applied to the diffracted light ratio monitor section 9 as the 0th order diffracted light intensity signal h0.

Next, when an OFF signal is output as a 0N10FF signal e to the shutter 5 and an ON signal is output as a 0N10FF signal f to the shutter 6, the detector 7 detects the primary needle point C and is amplified by the amplifier 8 which outputs the voltage signal g1. and is applied to the diffracted light ratio monitor section 9 as a first-order diffracted light intensity signal h1.

The diffracted light ratio monitor section 9 sequentially outputs the 0th order diffracted light intensity signal h0.
and the first-order diffracted light intensity signal h1, the diffracted light ratio h, /h
O is calculated and outputted to the terminal 200 as a diffracted light ratio.

Figure 2 shows the O-order diffracted light intensity in the example shown in Figure 1;
This is a graph showing the relationship between the 1st-order diffracted light intensity and the sampling time. For example, if the development start time is O, the sampling start time of the 0th-order diffracted light is 0, and the sampling interval is t, then the 0th-order diffracted light intensity time series h6(0), ha(t) , ha(2
t)...ho(nt) is obtained, and if to(0<to<t) is the sampling start time of the first-order diffracted light and the sampling interval is t, then the first-order diffracted light intensity time sequence h+(to
), h+(to+t), b+(to"2t)・"h+(
to+nt) is obtained.

Therefore, by calculating the diffracted light ratio from the 0th-order diffracted light intensity time sequence and the 1st-order diffracted light intensity time sequence, the diffracted light ratio sequence h+
(to)/ha(o), b+(to+t)/ha(t
), h + (to + 2t) / h o (2t)...
... h 1 (to + nt)/ho (nt) will be obtained.

Therefore, by monitoring this diffracted light ratio sequence, the progress of development can be monitored. Further, in order to easily control the development time in the development of an optical disk master, exposure and development conditions are usually set so that the development time is 50 to 200 degrees.

As a result, the sampling of the 0th-order diffracted light and the 1st-order diffracted light is, for example, t = 50 m5ec t = 100ms
ec is sufficient as the sampling resolution.

〔Effect of the invention〕

The development monitoring method of the present invention detects the 0th-order diffracted light and the 1st-order diffracted light obtained as development progresses using one detector, and amplifies them with one amplifier, thereby controlling the sensitivity characteristics of the detector and the first-order diffracted light. There is an advantage that there is no need for correction due to differences in offset and gain characteristics of amplifiers, and further, changes in the ratio of diffracted light can be eliminated even with respect to changes in characteristics due to deterioration of the detector and amplifier.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing one embodiment of the present invention, and Fig. 2 is a schematic diagram showing an embodiment of the present invention.
FIG. 3 is a graph showing the relationship between the 0th-order diffracted light intensity, the 1st-order diffracted light intensity, and the sampling time in the embodiment shown in the figure, and FIG. 3 is a schematic diagram showing a conventional example. 1... Optical disc master, 2... Old chuck table, 3... Spindle, 4... Detection control unit, 5゜6... Shutter, 7 .7a, 7
b. Old...detector, 8.8a, 8b... amplifier, 9. old... diffracted light ratio monitor section, 10... diffracted light ratio detection section, a... ... Laser light, b. Old... 0th order diffracted light, C. Old... 1st order diffracted light, d... Start signal, e... Kawasha 0N10FF signal, g +
g o r g 1”””voltage signal, h, ho, h+
......Diffraction light intensity signal, k...mark/diffraction light ratio signal, 100,200...Terminal, to, t, 2t. 3t, ~nt...-time, ho(o)
, ho(t), ho(2t), h. (3t)~ho(nt)""...0th order diffracted light intensity, h+
(to), h+(to+t), h+(to+2
t), b+(to+2t)~b+(to+nt) old・
・First-order diffraction light intensity. Agent: Susumu Uchihara, Patent Attorney Figure 2, Figure 3

Claims (1)

[Claims] Spin-developing an optical disc master, irradiating a laser beam perpendicularly to the patterned surface of the optical disc master, and detecting 0th-order diffracted light and 1st-order diffracted light among the diffracted lights obtained as development progresses using one detector. A development process characterized by calculating a diffracted light ratio from a time sequence of the 0th-order diffracted light intensity and a time sequence of the 1st-order diffracted light intensity obtained by sampling alternately, and monitoring the progress of development using the time sequence of the diffracted light. Monitoring method.