JP3864760B2 - Master exposure method, master exposure apparatus and master - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a master exposure method for recording information on a master that rotates using a light beam, and more specifically, forms a pattern for generating a clock signal on the master and detects a signal obtained by detecting the formed pattern. The present invention relates to a new master exposure method for recording information on a master with high positional accuracy.
[0002]
[Prior art]
This type of master exposure apparatus rotates the glass master with the photoresist applied by a spindle motor and moves it in the radial direction of the glass master while irradiating the photoresist with a light beam, thereby forming information pits in a spiral or concentric shape. Form a row.
[0003]
In many cases, visible light or ultraviolet laser light is used as the light beam. However, in order to realize high-density recording, an apparatus using a fine electron beam has been developed.
[0004]
The spindle motor is equipped with a rotary encoder that generates an electrical signal of several thousand pulses per revolution in order to control the rotation of the motor with high accuracy. PLL (Phase Locked Loop) control is performed on the basis of the electrical signal generated by the rotary encoder so as to prevent the displacement of the recorded information pit due to the rotational fluctuation of the glass master.
[0005]
[Problems to be solved by the invention]
An example of this is an “optical disc master exposure apparatus” described in JP-A-8-212552. This master exposure apparatus detects a motor angular velocity from a rotary encoder attached to a spindle motor, and varies the exposure timing of information to be recorded according to the detected angular velocity.
[0006]
However, this method has two problems. One is a problem of eccentricity due to the attachment of the rotary encoder attached to the spindle motor. If there is this eccentricity, even if the spindle motor rotates at a constant angular velocity, a signal as if there is a rotation fluctuation synchronized with the rotation cycle is output from the rotary encoder, and the position of the information pit recorded on the master disk Accuracy will deteriorate.
[0007]
In addition, even if the recorded data of information is corrected based on the output signal of the rotary encoder against this eccentricity, an attempt is made to create an information pit of the same length on the master disk, but in actuality, once per cycle. Long information pits and short information pits are created.
[0008]
The second is a problem of jitter due to rotation unevenness (so-called wow and fluttering) of the spindle motor. If there is jitter due to rotation irregularities of the spindle motor in the output of the rotary encoder that is the signal source, the subsequent PLL control will limit the frequency band until the influence of the jitter is eliminated by the loop filter. It will not be possible to make precise corrections. Therefore, there is a problem in that correction is limited by the jitter of the rotary encoder itself when obtaining uniformity within one turn of the master.
[0009]
By the way, it is known that this rotational unevenness generally increases as the rotational speed decreases. In recent years, an electron beam exposure apparatus that meets the demand for high-density recording has attracted attention. However, when exposure is performed with this electron beam exposure apparatus, the rotation speed of the master is reduced from the relationship between the photoresist sensitivity and the electron beam intensity. There are many cases. Also, when shorter information pits are produced for high-definition recording, the number of rotations is further reduced due to the modulation band of the electron beam. For this reason, in the electron beam exposure apparatus, the problem of uneven rotation of the master disk rotation system becomes more serious.
[0010]
From such a background, an object of the present invention is to provide a method and an apparatus for recording with high accuracy by eliminating positional deviation of information pits due to eccentricity due to mounting of a rotary encoder in a master exposure apparatus and rotation unevenness of a master rotating system. And
[0011]
[Means for Solving the Problems]
The first invention provides an exposure method that solves the problems of eccentricity and rotational unevenness.
[0012]
In the present invention, a pattern for generating a clock signal, that is, a rotary encoder is formed on the master itself by the master exposure apparatus. That is, by eliminating the act of attaching the rotary encoder to the motor, the problem of eccentricity due to the installation error of the rotary encoder can be eliminated.
[0013]
Also, when this rotary encoder is formed, a rotary encoder with extremely low jitter can be formed by selecting a rotation speed at which the influence of the rotation unevenness of the master disk rotation system can be ignored in practice, and problems caused by rotation unevenness can be eliminated. it can.
[0014]
Next, when recording information on the master, the rotary encoder formed in this way is detected by a detector, and information pits with high positional accuracy are recorded by creating information exposure timing based on the detection signal. It becomes possible to do.
[0015]
The second invention is a method of selecting a light source, an optical modulator, and a master disk rotation speed suitable for exposure of each of the rotary encoder and the information pit in the first invention.
[0016]
Usually, the light source, the optical modulator, and the master disk rotation speed are often determined from the recording conditions of the information pits, and the master disk rotation system sometimes includes a lot of rotation unevenness. In particular, when an electron beam is used as a light source, the rotational speed is relatively low, and therefore there is a lot of rotational unevenness.
[0017]
In such a case, the recording conditions of the rotary encoder are, for example, a laser beam as the light source and a laser beam modulator as the optical modulator, and the rotation speed of the master disk is at a level where the rotation unevenness of the master disk rotation system can be ignored in practice. By selecting a relatively high speed or a rotational speed shifted from the natural frequency of the master disk rotation system, a rotary encoder with extremely low jitter can be formed on the master disk. Based on the output of this rotary encoder, By creating the exposure timing of the information pits by the electron beam, this rotation unevenness problem can be solved.
[0018]
The third invention provides an exposure apparatus for recording information pits with high positional accuracy by solving the problems of the eccentricity and rotation unevenness.
[0019]
First, the master exposure apparatus of the present invention is based on a light source, a clock signal generating means, a pattern recording signal generating means, a light modulating means, a master sensitive to light beams, and a clock signal generated by the clock signal generating means. A master driving means for rotating or rotating the master and moving in the radial direction of the master, a detecting means, and an information recording signal creating means.
[0020]
Then, the pattern recording signal generating means generates a pattern recording signal for forming a pattern for generating a clock signal on the master disk based on the clock signal generated by the clock signal generating means, and optical modulation is performed in accordance with the pattern recording signal. The means turns on / off the light beam emitted from the light source and forms a pattern on the surface of the master disk whose rotation is controlled by the master disk drive means at a predetermined number of rotations.
[0021]
Next, based on a detection signal generated by detecting a pattern formed on the surface of the master, the information recording signal creating means creates an information recording signal for recording information on the master, and the light modulating means By turning on / off the light beam emitted from the light source in accordance with the information recording signal and recording information on the surface of the master disk whose rotation is controlled at a predetermined number of revolutions by the master disk driving means, A master of accuracy can be created.
[0022]
The fourth invention provides a master disk in which the number of output pulses of the rotary encoder is the least common multiple of the number of pulses per circumference of each zone where information pits are recorded or an integer multiple thereof.
[0023]
In recent years, when recording information pits on a master disk, the area to be recorded is divided into a plurality of zones, and recording is performed with different numbers of pulses (frequency) for each zone.
[0024]
At this time, by making the number of pulses of the rotary encoder as the least common multiple of the number of pulses of each zone or an integer multiple thereof, the respective clock signals when recording information pits in each zone are derived from the detection output of the rotary encoder. Can be easily created.
[0025]
The fifth invention provides a photosensitive material suitable for forming a rotary encoder on a master. A rotary encoder suitable for detecting a change in reflectivity or phase of reflected light is formed by using a material whose reflectivity or phase changes by being exposed to a portion forming a rotary encoder on the master. be able to. Examples of such a material include a phase change material, a metal film, a metal film coated with a photoresist, a film coated with a photoresist having a different thickness, and phthalocyanine.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the technique of the present invention will be described in detail with reference to the drawings.
[0027]
FIG. 1 shows an embodiment of a method for forming a rotary encoder on a master in the master exposure method of the present invention. In FIG. 1, 1 is a master, 2 is a laser light source, 3 is a clock oscillator, 4 is a pattern recording signal generator, 5 is an optical modulator, 6 is a motor controller, and 7 is a spindle motor.
[0028]
In FIG. 1, a pattern recording signal generator 4 supplies information to be recorded as an electrical signal to an optical modulator 5 with reference to a clock generated by a clock oscillator 3, and the optical modulator 5 receives a laser beam from a laser light source 2. Is switched to an optical signal for turning on / off, and the master 1 is irradiated. The master 1 is rotated by a spindle motor 7 that is driven to rotate by a motor control unit 6 in response to a rotation command signal generated by a pattern recording signal generator 4 with reference to a clock generated by a clock oscillator 3, and optical modulation is performed. A rotary encoder is formed on the surface by the laser light that is modulated and irradiated by the device 5.
[0029]
FIG. 5 shows a master having a rotary encoder formed on the surface. FIG. 5A shows a case where a rotary encoder is formed in an area (encoder area) 21 near the outer periphery of the master 20 and information to be recorded in an inner area (data area) 22 is formed as information pits. . FIG. 5B shows the case where the vicinity of the center of the master is the encoder area 21 and the outer area is the data area 22. It is desirable that the material of the encoder area 21 and the thickness of the resist layer are different from those of the data area 22 in accordance with the encoder detection method.
[0030]
FIG. 2 shows an embodiment of a method for recording information pits on a master in the master exposure method of the present invention. 2 that are common to FIG. 1 are denoted by the same symbols. 2 includes a phase comparator (PD) 91, a loop filter (LF) 92, a voltage controlled oscillator (VCO) 93, a 1 / N frequency divider (1 / N) 94, a formatter (FS). ) 95 to form a write clock PLL circuit.
[0031]
The rotary encoder formed on the surface of the master 1 by the method described in FIG. 1 is detected by the encoder signal detector 8, and the detected signal is input to the phase comparator 91, which is used as a reference signal for the other input. A phase error signal with the output of the 1 / N frequency divider 94 is generated. This phase error signal is input to the voltage controlled oscillator 93 through the loop filter 92. The output of the voltage controlled oscillator 93 is fed back to the phase comparator 91 via the 1 / N frequency divider 94.
[0032]
The output of the voltage controlled oscillator 93 is given to the formatter 95 as a write clock signal. The write clock signal is an output of the above-described write clock PLL circuit, and is a signal having a frequency N times (reciprocal of the division ratio) in synchronization with the encoder output. The formatter 95 generates a signal for forming information pits based on the write clock signal and applies it to the optical modulator 5 that performs on / off control of the laser beam, and records information pits on the surface of the master 1.
[0033]
By the way, in general, the motor rotation unevenness tends to decrease as the rotational speed of the rotating body increases, although it depends on the moment of inertia of the rotating body.
[0034]
FIG. 6 shows the number of rotations of the motor and the state of rotation unevenness at the time of exposure of the master disk by measuring the frequency of the output pulse of the rotary encoder attached to the motor.
[0035]
The horizontal axis represents the time for one round, and the vertical axis represents the frequency of the rotary encoder output pulse. When the number of rotations of the motor is 200 rpm, frequency fluctuation that seems to reflect the number of poles of the motor, that is, rotation unevenness is observed. At 1000 rpm, the amplitude decreases, but rotation irregularities still remain. When the rotational speed reaches 3000 rpm, the rotational unevenness becomes a negligible level, and the swell of one round and one cycle due to the eccentricity when the rotary encoder is attached becomes conspicuous. This undulation is avoided by creating the rotary encoder by the exposure apparatus itself.
[0036]
As a specific example, a master disk having a diameter of 200 mm and a thickness of 6 mm is used for a 3.5-inch magneto-optical disk. In this magneto-optical disk, a rotary encoder is formed on the surface of the master at a spindle motor rotational speed of 3000 rpm.
[0037]
Next, a rotary encoder formed on the master disk is detected by an encoder signal detector, information pit exposure timing is created based on this detection signal, and the information pit is recorded on the master disk at a spindle motor rotation speed of 1000 rpm. In this way, a master with high recording position accuracy can be produced.
[0038]
Here, let us look at the detection method of the rotary encoder. The encoder signal detector 8 in FIG. 2 includes a method for detecting an encoder signal and a method for detecting a change in reflectance and a method for detecting a change in phase.
[0039]
In the method of detecting a change in reflectance, a rotary encoder may be manufactured by making a portion of the encoding region 21 in FIG. 5 as a phase change material or a metal film having a low reflectance and making a hole therewith using laser light. Alternatively, a photoresist having a thickness of λ / 4n (λ is the wavelength of the encoder signal detector and n is the refractive index of the photoresist) may be coated on a metal film having a low reflectance.
[0040]
When exposure is performed with an appropriate exposure power, the reflectance of the exposed portion changes. In the method of detecting the reflectance, there may be small jitter due to the edge of the exposed rotary encoder pattern, but even in this case, the absolute value of the jitter can be suppressed to an order of magnitude smaller than that of the conventional encoder. it can.
[0041]
Further, in the method for detecting the phase change, a photoresist having a thickness λ / 8n thinner than that in the case of detecting the change in reflectivity on the metal film having a low reflectivity in the portion of the encode region 21 in FIG. It is good to coat. Alternatively, the glass substrate may be coated with a photoresist having the same thickness as that described above, exposed, and then developed to create irregularities.
[0042]
As the phase detector, a generally used one as shown in FIG. 7 may be used. In FIG. 7, 30 is a master on which a rotary encoder is formed, 31 is a semiconductor laser having a wavelength of 780 nm, 32 is a mirror, 33 is a half mirror, and 34 is a detector.
[0043]
The laser light emitted from the semiconductor laser 31 is diffracted by the rotary encoder 30 formed on the master 30 and reflected by the mirror 32, and the two diffracted lights of the transmitted light and the reflected light by the half mirror 33 are incident on the detector 34. . This incident light is converted into an electrical signal and binarized to create an encoder signal.
[0044]
Now, assuming that the rotary encoder is formed with lines and spaces having a radius of 80 mm and 0.5 μm, a signal of 1,000,000 pulses can be obtained in one round. This means that when information pits are recorded at a position of a radius of 30 mm, for example, an encoder pulse is obtained every 0.188 μm, a fine format signal can be created, and precise information pits can be recorded.
[0045]
According to this method, it is possible to form a much higher number of pulses per revolution than the conventional rotary encoder used for mounting a motor, and therefore it is possible to create a more accurate PLL write clock signal. Become.
[0046]
In addition, by forming the rotary encoder in this way, there is an advantage that an encoder signal having a convenient number of pulses can be obtained according to the pattern of the rotary encoder to be formed. By setting the number of pulses of the rotary encoder to the least common multiple of the number of pulses per round of each zone of the master data area or an integer multiple thereof, a formatter for recording information pits in the master data area It can be easy to create.
[0047]
FIG. 3 shows an embodiment of a master exposure apparatus that realizes the master exposure method described so far. 3 that are common to FIGS. 1 and 2 are denoted by the same reference numerals. In this embodiment, a laser light source is used as a light source for exposure, but other combinations of an electron beam and an electron beam modulator are possible.
[0048]
FIG. 4 shows an embodiment of an apparatus having a configuration in which a laser beam is used as a light beam when forming a rotary encoder on a master and an electron beam is used as a light beam when forming information pits.
[0049]
4 that are the same as those in FIGS. 1 and 2 are denoted by the same symbols. The pattern recording signal generator 4 gives information to be recorded as an electrical signal to the optical modulator 5 with reference to the clock generated by the clock oscillator 3, and the optical modulator 5 turns on / off the laser light from the laser light source 2. The master 1 is irradiated instead of the optical signal. The master 1 is rotated by a spindle motor 7 that is driven to rotate by a motor control unit 6 in response to a rotation command signal generated by a pattern recording signal generator 4 with reference to a clock generated by a clock oscillator 3, and optical modulation is performed. Then, the rotary encoder is formed on the surface of the master by the irradiated laser beam.
[0050]
Next, the rotary encoder created on the surface of the master 1 is detected by the encoder signal detector 8, and the detected signal is input to the phase comparator 91, which is used as a reference signal for 1 / N minutes which is the other input. A phase error signal from the output of the frequency divider 94 is generated.
[0051]
This phase error signal is input to the voltage controlled oscillator 93 through the loop filter 92. The output of the voltage controlled oscillator 93 is fed back to the phase comparator 91 via the 1 / N frequency divider 94. The formatter 95 generates a signal for forming information pits based on the write clock signal and applies it to the electron beam modulator 11 that performs on / off control of the electron beam emitted from the electron beam source 10. Record information pits.
[0052]
For example, a rotary encoder is formed on the surface of the master using a laser beam at a spindle motor rotational speed of 3000 rpm. Next, an information pit exposure timing is created based on the detection output of the rotary encoder, and the information pit is recorded at a spindle motor rotational speed necessary for high-density recording, for example, 200 rpm, using an electron beam. Thus, information pits with high density and high positional accuracy can be recorded.
[0053]
In the embodiment of FIG. 4, a combination of a laser light source and an electron beam is shown as an exposure light source for pattern formation and information recording, respectively. A combination of two types of electron beams having different wavelengths is also possible.
[0054]
The embodiment of the master exposure method and master exposure apparatus for recording information with high positional accuracy has been described above. Up to this point, the magneto-optical disk has been mainly described as an example, but the exposure method, the exposure apparatus, and the master disk of the present invention can also be applied to the production of master disks of other optical disks or magnetic disks. .
[0055]
From here on, the photosensitive material used when the rotary encoder is exposed on the glass master will be described. There are photosensitive materials whose phase changes due to exposure and those whose reflectance changes, which will be described with reference to specific examples.
[0056]
[Example 1]
FIG. 8 is a diagram showing a process when a rotary encoder is formed on a glass master using a phase change material as a photosensitive material. In the forming process, (a) a phase change material 41 such as InSb is formed into a thickness of 100 nm by sputtering on a portion of the glass master 40 whose surface has been polished, and (b) a rotary encoder near the outer periphery, and SiN is formed thereon. A protective film 42 such as 20 nm thick is formed by sputtering. At this time, it is necessary to protect the data recording area of the glass substrate from this sputtering.
[0057]
FIG. 14 shows the protection state, in which 80 is a glass master, 81 is a turntable for mounting the master, 82 is a mask made of a soft magnetic material for protecting the data recording area, and 83 is a magnet. The data recording area near the center of the glass master 80 is covered with a mask 82 held by a magnet 83 to protect it from sputtering.
[0058]
Returning to FIG. 8, the mask is removed after sputtering, and (c) a photoresist layer 43 is spin-coated to a predetermined thickness on the glass master. Next, (d) the photoresist on the portion where the phase change material 41 is formed with a photoresist solvent is removed, and then prebaked at 100 ° C. for 30 minutes to prepare a master.
(E) This master is mounted on a master exposure apparatus as shown in FIG. 3, and a rotary encoder is formed by exposing the phase change material portion with a laser beam having a wavelength of 350 nm and an exposure power of 5 mW with a spindle motor rotating at 3000 rpm. To do.
[0059]
Since the rotary encoder to be formed is read-only, it is sufficient if a change in reflectivity occurs. Therefore, initialization processing is not necessary. Further, the exposure pitch is set to about 0.2 μm, and overwriting is performed with adjacent tracks. By doing so, it is possible to form a rotary encoder having a highly accurate radial pattern over one round.
[0060]
Next, as shown in FIG. 3, an encoder signal detector 8 is installed on the upper part of the formed rotary encoder, and the information pits are recorded at a rotational speed low enough to correct the exposure pit length. High-precision and high-density information pits can be recorded.
[0061]
[Example 2]
FIG. 9 is a diagram showing a process when a rotary encoder is formed on a glass master using a thin metal film as a photosensitive material. (A) A metal film 51 of chromium oxide or the like is formed to a thickness of 50 nm by sputtering on a portion of the glass master 50 whose surface is polished, and (b) a rotary encoder near the outer periphery is formed. (C) A photoresist 52 is spin-coated to a predetermined thickness. (D) The photoresist of the metal film 51 is removed with a photoresist solvent and prebaked at 100 ° C. for 30 minutes. (E) The metal film 51 is exposed with a laser beam having a wavelength of 350 nm and an exposure power of 10 mW at a rotation speed of the spindle motor of 3000 rpm. As a result, a hole is made in the metal film to form a rotary encoder.
[0062]
Example 3
The present embodiment is an embodiment in the case where information pits are formed by an electron beam in the second embodiment. Referring to FIG. 9, (a) a metal film 51 of chromium oxide or the like is formed to a thickness of 50 nm by sputtering on a portion of (a) a glass master disk 50 whose surface has been polished and (b) a rotary encoder near the outer periphery. (C) A photoresist 52 for electron beam is spin-coated with a predetermined thickness. (D) The portion of the photoresist 52 where the rotary encoder is to be formed is removed with a solvent and prebaked at 100 ° C. for 30 minutes.
(E) This master disk is set in an electron beam exposure apparatus incorporating a laser beam as shown in the example of FIG. 4, the rotation speed of the spindle motor is 3000 rpm, a laser beam having a wavelength of 350 nm and an exposure power of 10 mW. 51 portions are exposed. As a result, a hole is made in the metal film to form a rotary encoder. Similar to the first embodiment, a change in reflectance is detected, and information pits are recorded with an electron beam at a predetermined rotational speed. Thus, a master disc on which information is recorded with high positional accuracy is completed.
[0063]
Example 4
FIG. 10 is a diagram showing a process when a rotary encoder is formed by coating a glass master with a photoresist on a metal having a low reflectance as a photosensitive material. In FIG. 10, (a) a metal film 61 having a low reflectance such as chromium oxide is formed by sputtering on a portion of (a) the glass master 60 whose surface has been polished, on which (b) a rotary encoder near the outer periphery is formed. (C) A photoresist 62 is spin-coated to a predetermined thickness. (D) Further, a photoresist 63 having a high viscosity is spin-coated only on a portion where a rotary encoder is to be formed, and prebaked at 100 ° C. for 30 minutes. (E) The photoresist is exposed with a laser beam having a wavelength of 350 nm and an exposure power of 0.5 mW at a rotation speed of the spindle motor of 3000 rpm. The exposed portion of the photoresist is not burned, and a concavo-convex pattern of the rotary encoder can be formed without development.
[0064]
Example 5
In this embodiment, a photoresist is coated only on a portion where the rotary encoder is formed in the fourth embodiment. Referring to FIG. 11, (a) a metal film 61 having a low reflectance such as chromium oxide is formed by sputtering on a portion of (a) the glass master 60 whose surface has been polished, and (b) a rotary encoder near the outer periphery. .
(C) A photoresist 62 is spin-coated with a predetermined thickness on the portion where the rotary encoder is to be formed. (D) Further, a photoresist 63 having a high viscosity is spin-coated on the portion where the rotary encoder is to be formed, and prebaked at 100 ° C. for 30 minutes. (E) The photoresist 63 is exposed with a laser beam having a wavelength of 350 nm and an exposure power of 0.7 mW at a rotation speed of the spindle motor of 3000 rpm. The exposed portion of the photoresist is not burned, and a concavo-convex pattern of the rotary encoder can be formed without development.
[0065]
Example 6
FIG. 12 is a diagram showing a process when a rotary encoder is formed on a glass master using a high-viscosity photoresist as a photosensitive material. In the forming process, (a) a glass master disk 70 having a polished surface is spin-coated with (b) a photoresist 71 to a predetermined thickness. (C) A photoresist 72 with increased viscosity is spin-coated on the portion where the rotary encoder is to be formed, and prebaked at 100 ° C. for 30 minutes.
(D) The photoresist 72 is exposed with a laser beam having a spindle motor speed of 3000 rpm, a wavelength of 350 nm, and an exposure power of 1 mW.
[0066]
Next, development is performed on the exposure apparatus so that the developer is applied only to the rotary encoder. At this time, the rotation speed of the spindle motor is set to 300 rpm so that the developer does not enter the data area and does not bounce from the outside. The developer is washed by flowing 5 ml for 10 seconds, and then flowing 50 ml with pure water for 1 minute. Gradually increase the number of revolutions of the spindle motor to 800 rpm to dry, and then collect the developer and pure water. FIG. 15 shows the state at this time. In FIG. 15, 85 is a glass master, 86 is a turntable, and 87 is a developer recovery unit. By giving the turntable 86 a reverse taper as shown by a broken line in FIG. 15 so that the developer and pure water do not flow out of the turntable 86, the developer and pure water can be prevented from rebounding.
[0067]
Example 7
FIG. 13 is a diagram showing a process when a rotary encoder is formed on a glass master using phthalocyanine as a photosensitive material. (A) A portion where (b) a photoresist 81 is spin-coated to a predetermined thickness on a glass master 80 whose surface has been polished, and (c) a rotary encoder near the outer periphery is formed with a solvent of the photoresist. The photoresist is removed and prebaked at 100 ° C. for 30 minutes. Next, (d) phthalocyanine is spin-coated on the portion where the rotary encoder is to be formed. The master is set in a master exposure apparatus, and (e) the phthalocyanine portion is exposed with a laser beam having a wavelength of 350 nm and an exposure power of 3 mW with a spindle motor rotating at 3000 rpm. Since the reflectance of the exposed portion decreases, a rotary encoder that detects a change in reflectance can be formed by this method.
[0068]
(Appendix 1) A master exposure method for recording information on a master,
Perform the first exposure to form a pattern to generate a clock signal on the surface of the master,
A clock signal is created based on a detection signal obtained by detecting a pattern formed on the master in the first exposure, and information is recorded on the surface of the master using the clock signal as a reference for exposure timing. A master exposure method, wherein the second exposure is performed.
[0069]
(Supplementary Note 2) A master exposure method for performing exposure by irradiating a light beam to a master that is rotated or rotated by the master drive means and moved in the radial direction of the master,
Supplementary note 1 characterized in that exposure is performed by changing the type of light beam used for the first exposure and the second exposure, the light modulation means, and the rotational speed of the master together or individually. The master exposure method described.
[0070]
(Appendix 3) a light source,
Clock signal generating means;
Pattern recording signal generating means;
Light modulation means;
A master that is exposed to light,
Master drive means for rotating or rotating the master and moving it in the radial direction of the master based on the clock signal generated by the clock signal generator;
Detection means;
An information recording signal creating means,
The pattern recording signal generating means generates a pattern recording signal for forming a pattern for generating a clock signal on the master on the basis of the clock signal generated by the clock signal generating means, and the light modulating means responds to the pattern recording signal. A pattern is formed on the surface of the master that is controlled to rotate at a predetermined number of revolutions by the master driving means by turning on / off the light beam emitted from the light source,
Based on the detection signal generated by detecting the pattern formed on the surface of the master, the information recording signal generator creates an information recording signal for recording information on the master, and the light modulator is used for this information. The master exposure is characterized in that information is recorded on the surface of the master whose rotation is controlled at a predetermined rotation speed by the master driving means by turning on and off the light beam emitted from the light source in accordance with a recording signal. apparatus.
[0071]
(Additional remark 4) It is the original disc produced with the original disc exposure method of Additional remark 1,
The pattern formed by the first exposure is a pattern for a rotary encoder,
The master, wherein the number of pulses per round of the rotary encoder is the least common multiple of the number of pulses per round of each zone of information recorded on the master in the second exposure or an integral multiple thereof.
[0072]
(Additional remark 5) It is the original disc produced with the original disc exposure method of Additional remark 1,
A master, wherein a material for forming a pattern for generating a clock signal on the master is a material whose reflectance or phase is changed by exposure.
[0073]
(Appendix 6) A master disc produced by the master exposure method described in Appendix 1,
A master, wherein a material for forming a pattern for generating a clock signal on the master is a phase change material.
[0074]
(Appendix 7) A master disc produced by the master exposure method described in Appendix 1,
1. A master, wherein a material for forming a pattern for generating a clock signal on the master is a metal film or a metal film coated with a photoresist.
[0075]
(Additional remark 8) It is the original disc produced with the original disc exposure method of Additional remark 1,
A master, wherein a material for forming a pattern for generating a clock signal on the master is coated with a photoresist having a different thickness.
[0076]
(Supplementary note 9) The master exposure method according to supplementary note 2,
The light beam in the first exposure is a laser beam;
A master exposure method, wherein the light beam in the second exposure is an electron beam.
[0077]
(Supplementary Note 10) a laser light source;
Clock signal generating means;
Pattern recording signal generating means;
Laser light modulation means for turning on / off the laser light emitted from the laser light source according to the pattern recording signal;
A master disc that is sensitive to laser light emitted from the laser light modulation means;
A master driving means for rotating or rotating the master and moving it in the radial direction of the master based on the clock signal generated by the clock signal generating means;
The pattern recording signal generating means generates a pattern recording signal for forming a pattern for generating a clock signal on the master disk with reference to the clock signal generated by the clock signal generating means, and the pattern recording signal is generated according to the pattern recording signal. A light modulation means turns on / off the laser light emitted from the laser light source, and forms a pattern on the surface of the original disk whose rotation is controlled at a predetermined number of rotations by the original disk drive means,
An electron beam light source;
An electron beam modulating means for turning on / off the electron beam emitted from the electron beam light source according to the information recording signal;
A detection unit that detects a pattern formed on the surface of the master and generates a detection signal; and an information recording signal generation unit that generates a signal for recording information on the master based on the detection signal;
Based on a detection signal generated by the detection means detecting the pattern formed on the surface of the master, the information recording signal creation means creates an information recording signal for recording information on the master, and the electron beam modulation A means for turning on / off an electron beam emitted from the electron beam light source in accordance with the information recording signal and recording information on the surface of the original disk whose rotation is controlled at a predetermined number of revolutions by the original disk drive means; A master exposure apparatus.
[0078]
【The invention's effect】
As described above in detail, according to the first invention, a rotary encoder is formed on the master by rotating the spindle motor at a speed with little rotation unevenness in the master exposure apparatus, and the detection signal of the formed rotary encoder is used as a detection signal. By creating the exposure timing of information pits by applying a PLL, information pits having a uniform periodic interval in the circumferential direction of the disc can be produced.
[0079]
In addition, according to the second invention, by changing the exposure light source for forming the rotary encoder on the master and the exposure light source for recording information, a suitable manufacturing method can be obtained.
[0080]
According to the third aspect of the present invention, the rotary motor is formed on the master by rotating the spindle motor at a speed with little rotation unevenness, and the detection signal of the formed rotary encoder is multiplied by the PLL to expose the information pits. Thus, it is possible to realize a master exposure apparatus that produces information pits having a uniform periodic interval in the circumferential direction of the disc.
[0081]
Further, according to the fourth invention, the number of pulses of the rotary encoder is produced as the least common multiple of the number of pulses of each zone of the data area or an integral multiple thereof, so that each information pit when recording information pits in each zone The clock signal can be easily created from the detection output of the rotary encoder.
[0082]
Moreover, according to the fifth aspect, by using this material, a rotary encoder suitable for detection can be formed by exposure.
[Brief description of the drawings]
FIG. 1 shows an embodiment of a method for forming a rotary encoder on a master disk of the present invention.
FIG. 2 shows an embodiment of a method for recording information on a master disk according to the present invention.
FIG. 3 shows an embodiment of a master exposure apparatus according to the present invention.
FIG. 4 shows an embodiment of a master exposure apparatus according to the present invention.
FIG. 5 is an explanatory diagram of a master on which the rotary encoder of the present invention is formed.
FIG. 6 is an explanatory diagram of motor rotation speed and rotary encoder output.
FIG. 7 shows an example of a phase detector.
FIG. 8 shows an embodiment in which a rotary encoder is formed on the master disk of the present invention.
FIG. 9 shows an embodiment in which a rotary encoder is formed on the master disk of the present invention.
FIG. 10 shows an embodiment in which a rotary encoder is formed on the master disk of the present invention.
FIG. 11 shows an embodiment in which a rotary encoder is formed on the master disk of the present invention.
FIG. 12 shows an embodiment in which a rotary encoder is formed on the master disk of the present invention.
FIG. 13 shows an embodiment in which a rotary encoder is formed on the master disk of the present invention.
FIG. 14 is an explanatory diagram for masking a master.
FIG. 15 is an explanatory view for cleaning the master.
[Explanation of symbols]
1, 20, 30 Master
2 Laser light source
3 Clock oscillator
4 Pattern recording signal generator
5 Optical modulator
6 Motor controller
7 Spindle motor
8 Encoder signal detector
9 Information recording signal generator
10 Electron beam source
11 Electron beam modulator
21 Encoder area
22 Data area
40, 50, 60, 70, 80, 85 Glass master
91 Phase comparator
92 Loop filter
93 Voltage controlled oscillator
94 1 / N divider
95 Formatter

Claims (5)

A master exposure method for recording information on a master,
The master is held to be rotatable or rotatable and movable in the radial direction of the master, and first exposure is performed to form a pattern for generating a clock signal on the surface of the master,
The rotatable or rotatable and while movably held in the radial direction of the master disc is rotated the master, the detection signal obtained by detecting the pattern formed on the master disk in the first exposure A master exposure method comprising: generating a clock signal based on the clock signal; and performing second exposure to record information on the surface of the master using the clock signal as a reference for exposure timing. A master exposure method for performing exposure by irradiating a light beam onto the master is Gana the radial movement of the rotation or the rotation and the master by the master drive means,
The exposure by changing both or individually with the optical modulation means and a rotational speed of the master for modulating the light beam of the type and light beam used in the above-described first exposure and the second exposure The master exposure method according to claim 1, wherein the master exposure method is performed. A light source;
Clock signal generating means;
Pattern recording signal generating means;
Light modulation means;
A master that is exposed to light,
A master drive means for moving the master disc in the radial direction of rotation or rotation and the master based on the clock signal the clock signal generating means generates,
Detection means;
An information recording signal creating means,
Generating a pattern recording signal for forming a pattern for on the basis of the clock signal generated by said clock signal generating means the pattern recording signal generating means for generating a clock signal to the master, according to the pattern recording signal the pattern is formed on the surface of the master which is the light modulating means is controlled to rotate at a predetermined rotational speed by the on / off to the master drive means a light beam emitted from the light source Te,
The detection means on the basis of a detection signal is generated by detecting the pattern formed on the surface of the master stored in the master drive means, said information recording signal producing means is held in the master drive means create an information recording signal for recording information on the master disk are,
The light modulation means turns on / off the light beam emitted from the light source in accordance with the information recording signal, and records information on the surface of the original disk whose rotation is controlled at a predetermined number of revolutions by the original disk drive means. A master exposure apparatus. A master produced by the master exposure method according to claim 1,
The pattern formed by the first exposure is a pattern for a rotary encoder,
Wherein the number of pulses per revolution of the rotary encoder is the least common multiple or integral multiple thereof the number of pulses per revolution of each zone of the information recorded on the master disk in the second exposure, master. A master produced by the master exposure method according to claim 1,
Material of the part forming the pattern for generating a clock signal to said master, characterized in that a material which changes its reflectance or phase by the first exposure, master.

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