KR100314089B1 - System of monitoring developed state of glass disk photoresist for manufacturing optical disk - Google Patents

Abstract

PURPOSE: A system of monitoring a developed state of a glass disk photoresist for manufacturing an optical disk is provided to use a CCD to sense information on a diffracted light passing through a glass disk, and to calculate the developed state of the photoresist as data by a controller on the basis of the information. CONSTITUTION: A reflector(22) is set between a light source and a glass disk(12). A CCD(20) senses information on a diffracted light, which is irradiated from the light source and passes through the glass disk(12). A controller(25) calculates a developed state of a photoresist applied to the glass disk(12) as data by the sensed information.

Description

Development status inspection system of glass disk photoresist for optical disc manufacturing

1 is a schematic perspective view showing an excerpt of a portion of a typical compact disc;

2 is a manufacturing degree schematically showing a general optical disc manufacturing process,

3 is a schematic diagram of a system for measuring the development state of the development of the photosensitive agent applied to the glass disk for manufacturing a conventional general optical disk,

4 is a schematic diagram of a system for inspecting the uniformity of development degree after development of a photosensitive agent applied to a glass disk for manufacturing a conventional general optical disk,

5 is a schematic configuration diagram of a system for measuring and inspecting a developing state of a glass disk photoresist for manufacturing optical discs according to the present invention;

FIG. 6 is a diagram showing the diffraction angles of the first and second diffraction light beams according to the respective track pitches and the positions on the CCD when the optical wavelength λ is 413 in FIG.

FIG. 7 is a block diagram of an interface circuit connecting the CCD and the central processing processor of the controller in FIG.

FIG. 8 is a flowchart of the central processing processor program included in the controller of the system for measuring and inspecting the developing state of the photosensitive agent in FIG.

* Explanation of symbols for main parts of drawings

11: light emitting source 12: glass disk

13: photosensitive film 14: developer

15: 0th order diffracted light 16.17: 1st order diffracted light

18, 19: 2nd diffracted light 15 ', 16': Photo Detector

17 ', 18', 19 ': photo detector 20: solid state image pickup device (CCD)

21: drive unit 22: reflector

23: Kr laser 24: Jig

30: controller 31,32: A / D converter

33: Multiplexer 34,35,38,39: Buffer

36,37: RAM

The present invention relates to an inspection system for developing a photosensitive agent applied to a glass disk for optical disk manufacturing, and more particularly, to a solid state image of a developing state of a photosensitive agent applied to a glass disk for obtaining a stamper on a disk master process in an optical disk manufacturing process. It relates to a system for inspecting using a device (CCD).

In general, an optical disc used as a medium for recording and / or playing back audio information or video information, such as a compact disc (CD), a laser disc (LD) and a magneto-optical disc (MOD), is a conventional contact recording / reproducing medium. Compared to LP recorders and tape recorders, it has a much higher capacity for storing large amounts of information and has excellent quality of information reproduction. Compact discs are becoming more and more popular.

The compact disc is a non-contact recording method using a laser. As shown in FIG. 1, the compact disc has an elliptical groove on one side of a disk having a diameter of 120 mm and a thickness of 1.2 mm made of transparent plastic as a base material. A plurality of pits 1 are formed to form a track 2, and an aluminum film is deposited on the pit to digitally record and record an audio signal and to reflect the laser light on the pit surface, thereby protecting aluminum. In order to reproduce the recorded information, the optical disk is rotated at a high speed to reproduce the reflected optical signal response by illuminating the laser light on the pit during reproduction.

As shown in the manufacturing process diagram schematically shown in FIG. 2, such an optical disk is manufactured by processing a glass disc into a glass disc through an invitation letter and ultra-precision polishing, and then fixing a photoresister to a predetermined thickness on the glass disc. Coated on the laser beam recorder.

Then, the high-density magnetic tape recorded by digitalizing the signal of the audio and video information to be recorded is tape mastered, that is, the EMF (Eight-to-Fourteen Modulation) to facilitate the optical recording and reproduction of the signal recorded on the high-density magnetic tape. Input to the laser beam recorder through a modulation process. In this case, the signal partially exposes the photoresist film formed on the glass disk which rotates by opening and closing the high power laser beam.

Then, as described above, after the laser beam recording is completed, a developer is sprayed onto the glass disc to dissolve the photosensitive agent in the exposed portion, thereby forming a fine elliptical groove called a pit, and vacuum depositing a metal thin film on the pit to form a so-called disc. This completes the Master.

Subsequently, a matrixing replication process is performed to copy a plurality of compact disks having the same signal from the disk master completed by the processor as described above. In the metric process, the signal of the disk master is performed. Nickel (Ni) is formed and separated on the surface by electroforming to form a nickel-father in which a signal is negatively transferred. Then, the same process is repeated on the nickel-fader to form a mother and a stamper.

In the replication process, a transparent resin substrate having the same signal as that of the original disk master is formed by injection molding the transparent resin into the original plate, and then a thin metal reflective film is formed on the signal surface by vacuum deposition. The coating of the protective film completes the manufacture of the compact disc.

Most of the optical disc manufacturing process as described above is performed through strict management of the manufacturing environment such as fine dust, temperature, humidity and vibration in the room in a clean room, and such environmental management is more severe than the semiconductor manufacturing process. It can be said that is required.

Particularly, in the above-described disc mastering process for obtaining a stamper in the optical disc manufacturing process, an error range for the film thickness of the photosensitive agent requires ultra-precision control of about ± 5 nm, while the photosensitive agent is developed within a short time, so that a predetermined apparatus By measuring the state in which the photosensitive agent is developed during the development process of the photosensitive agent, and after the development, by checking the uniformity of the state in which the photosensitive agent is developed, by adjusting the injection amount and time, etc. of the developing solution based on the optimal development conditions of the photosensitive agent Is setting.

The present invention is directed to an apparatus for measuring and inspecting the state and degree of development of the photosensitive agent as described above.

FIG. 3 and FIG. 4 schematically show the configuration of the photosensitive agent measuring and inspection system of the conventional optical disk manufacturing glass disk. FIG. 3 shows the developing state of the conventional optical disk manufacturing glass disk during photosensitive agent development. 4 is a schematic diagram of a system for inspecting the uniformity of the degree of development after photoresist development of a conventional general optical disk manufacturing glass disk.

Referring to FIGS. 3 and 4, in the conventional photosensitive agent measurement and inspection system of the optical disk manufacturing glass disk, the laser beam emitted from the light emitting source 11 provided under the glass disk 12 is the glass disk. (12) When the laser beam emitted from the luminescent source 11 provided below is vertically incident on the glass disk 12 and passes through the photoresist film 13, it maintains a constant angle according to the following equation (1). The diffracted light is diffracted into the 0th order diffracted light 15 and the 1st order (diffraction lights 16 and 17 and the 2nd order diffracted light 18 and 19).

In the formula (1), m represents diffraction orders such as 0th order, 1st order, 2nd order ... etc., θ _m is the diffraction angle, λ is the wavelength of incident light, p is the photosensitive agent applied on the glass disk. The track pitch of the pit when exposed to a recording laser is shown.

In the systems shown in FIGS. 3 and 4, the primary diffracted light 16, 17 and the secondary diffracted light 18, 19 are track pitches p of pits as shown in equation (1) above. And a diffraction angle (θ _m ) forming a functional relationship with the wavelength of the incident light (λ), and the photodetector (15 Detector, 15 ', 16', 17 ', 18', 19) is used in a conventional system. The photosensitive agent development state on the glass disk for optical disc manufacturing was measured and inspected by following formula (2) and (3) by sensing using ').

In other words,

In the above formulas (Z) and (3), W denotes the width of the pit, D denotes the depth of the pit (depth of the photosensitive agent developed), n _r denotes the reflective index of the photosensitive agent, and n _a denotes air. Refractive Index of is represented, I ₁ is the intensity of the first diffraction light, I ₂ is the intensity of the second diffraction light.

Here, in the recent optical disc manufacturing technology, the track pitch p of the pit is in a trend of increasing in density, gradually decreasing from 1.6 µm to 1.0 µm and 0,8 µm. Therefore, the track pitch change of the pit causes the diffraction angle (? M) of the diffracted light to change, which makes it difficult to accurately measure the photosensitive agent development state of the glass disc for manufacturing optical discs using the conventional system described above.

In addition, in the case of measuring the developing state of the photosensitive agent coated on the optical disk manufacturing glass disk shown in FIG. 3, the amount and time of the developing solution should be adjusted according to the measurement result. The second diffracted light is diffracted again when passing through the developer according to the amount of the developer 14, and the diffracted distance also changes according to the amount of the developer, so that when the developer is not constant, the developing state is fixed at a fixed position. The conventional fixed photodetector for measuring the problem was difficult to measure.

In addition, when the developer is sprayed onto the disk, when the developer flows down the disk, the developer forms a wave-like shape. As a result, the position of the diffracted light is changed randomly. Therefore, it is difficult to measure the developing state of the photosensitive agent using a conventional photodetector. Even if you measure or measure the accuracy was poor.

Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a solid state image pickup device (CCD) for a developing state of a photosensitive agent coated on a glass disc for obtaining a stamper on a disc master process in an optical disc manufacturing process. It is to provide a development status inspection system of glass disk photoresist for optical disk manufacturing that can be inspected more precisely using

The development state inspection system of the glass disk photosensitive agent for optical disk manufacturing of the present invention for achieving the above object is provided with a drive unit for turning the glass disk for manufacturing an orphan disk coated with the photosensitive agent and a light source for irradiating light to the glass disk In the photosensitive agent developing state inspection system, an optical path changing means is provided between the light source and the glass disk, and on the upper portion of the glass disk to detect the diffracted light transmitted from the light source and to store the optical information. Diffracted light sensing means is provided, and includes a control unit for reading and interpreting the light information sensed by the diffracted light sensing means to calculate the developing state of the photosensitive agent applied to the glass disk as data.

In the developing state inspection system of the glass disk photosensitive agent for optical disc manufacturing of the present invention, the optical path changing means is preferably a reflector, and the diffraction light detecting means is preferably a solid state imaging device (CCD). The control section stores therein an A / D converter for digitizing the optical information signal stored by the diffraction light detecting means, a RAM for storing and storing the digitized signal by the A / D converter, and the RAM. It is preferred to include a central processing processor for calculating the received signal as data on the developing state of the photosensitive agent.

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

5 shows a schematic configuration of a system for inspecting a developing state of a photosensitive agent applied to an optical disk manufacturing glass disk according to the present invention. Referring to this, the system according to the present invention is a glass disk for manufacturing a long disk coated with a photosensitive agent. A driving unit 21 for rotating 12 and a Kr laser 23 which is a light source for irradiating light to the glass disc 12, and between the glass disc 12 and the Kr laser 23 in a light source. A reflecting mirror 22 is provided to change the course of the emitted light at a predetermined angle. On the top of the glass disk 12, a solid state imaging device (CCD), which is a sensing means for sensing information about diffracted light diffracted while the light emitted from the Kr laser 23 passes through the glass disk 12; 20 is supported by the jig 24 and is spaced apart from the upper surface of the glass disc 12 by a predetermined height. The solid state imaging device (CCD) 20 reads information on the detected diffracted light. The control part 25 which analyzes and computes the developed state of the photosensitive agent apply | coated to the said glass disk 12 as data is connected.

On the other hand, according to a preferred embodiment of the present invention, the solid-state imaging device is preferably 70mm in width and 15mm away from the upper surface of the glass disk.

Then, the control unit 25 is an A / D converter (31, 32) and the A / D converter (31) for digitizing the signal for the diffracted light information detected by the solid state image pickup device (hereinafter referred to as CCD; 20) And RAM (36, 37) for storing and storing the signal digitized by 32) and a central processing processor for calculating the signal stored by the RAM (36 37) as data on the developing state of the photosensitive agent.

The inspection system of the photosensitive agent developing state of the glass disk for manufacturing optical disc of the present invention having the structure as described above is to measure and inspect the photosensitive agent developing state by the following working principle.

In other words, the diffracted light is formed at an arbitrary position on the CCD 20 according to the specification of the track pitch p of the pit and the amount of the developer.

FIG. 6 is a table showing the diffraction angles of the first and second diffracted light and the positions on the CCD according to the track pitch p.

Here, the light source used in the embodiment of the present invention used a 413Kr laser to measure the second-order diffracted light up to a track pitch of 0.85㎛, the CCD is 14㎛ × 14㎛ × 5.000 Elements (Blue) Color CCD is used.

As described above, the data stored through the CCD, that is, the information such as the intensity and angle of the diffracted light, are shown in the block diagram of the interface circuit connecting the CCD and the central processing processor included in the controller of the present invention illustrated in FIG. After the digitalization through the A / D converters 31 and 32, the data is stored in the RAMs 36 and 37 through the multiplexer 33 and the buffers 34 and 35, and the data is read back from the RAM and buffered. It is sent to a central processing processor (not shown) via (38, 39).

In this case, when the output of the information input by the CCD is divided into Even and Odd, when the output of the CCD is sequentially outputted to one output, the A / D converter 31 is used. After digitization, the data is sent directly to the central processing processor through the buffer 38. As such, when the information output by the CCD is divided into Even and Odd, the multiplexer 33 and the RAM 36 and 37 are digitized and sequentially rearranged through A / D conversion. The controller 30 sends a clock CLDCK and a control signal to each CCD element so as to adjust and synchronize them with the central processing processor.

The data sent to the central processing processor in this manner is the position on the CCD of the zero-order diffracted light read from the CCD along the flow shown in the flowchart of the central processing processor program included in the controller of the system of the present invention illustrated in FIG. Intensity, the position and intensity of the CCD image of the first and second diffracted light are calculated, and the diffraction angle [theta] m of the measuring disk is calculated using the resultant data, and the track pitch of the measuring disk is calculated from this [theta] m ([theta] m is Diffraction angle, m is the diffraction order of light).

Then, using the formula (2) and (3) and the measured intensity of the diffracted light is measured the development state of the photosensitive agent. At this time, if there is a CCD protective glass in the CCD element, by compensating for the diffraction deviation according to the The developing state of the photosensitizer can be measured.

As described above, the inspection system of the glass disk photosensitive agent developing state for manufacturing an optical disk according to the present invention is used to measure and inspect the developing state of the photosensitive agent applied to the glass disk for obtaining a stamper on the disk master process in the optical disk manufacturing process. Use a CCD. Thus, the CCD detects the information on the diffracted light that has passed through the glass disk, and based on the information, the control unit calculates the developing state of the photosensitive agent as data, so that the pitch fluctuation of the signal track recorded on the disk, the input amount of the developer, Regardless of the phenomenon of wave development in the developing process, it is possible to control the developing process through more precise measurement, to make accurate evaluation of the developing result, and to measure the track pitch during the developing process. to be.

Claims (4)

(Correction) A photosensitive agent developing state inspection system of an optical disk manufacturing glass disk, comprising: a driving unit for rotating a glass disk for optical disk production coated with a photosensitive agent; and a light source for irradiating light to the glass disk; It is provided with a long path changing means, the upper portion of the glass disk is provided with diffracted light detecting means for detecting information about the diffracted light transmitted from the light source and transmitted through the glass, the diffraction light detecting means And a control unit for calculating, as data, the developing state of the photosensitive agent applied to the glass master based on the received optical information. The system of claim 1, wherein the optical path changing means is a reflecting mirror. The system of claim 1, wherein the diffracted light detecting means is a solid state image pickup device (CCD). 2. The RAM according to claim 1, wherein the control unit includes an A / D converter for digitizing the optical information signal stored by the diffraction light detecting means, a RAM for storing and storing the digitized signal by the A / D converter, and the RAM. And a central processing processor for calculating the signal stored by the data as the data on the developing state of the photosensitive agent.