JP2001331980A - Stamper machining device and method for optical disk substrate manufacturing, stamper protective film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize variance in the eccentric amount of an inner diameter or outer diameter machining hole with respect to a signal on a stamper, and to improve machining accuracy in stamper machining for optical disk substrate manufacturing. SOLUTION: A stamper for optical disk substrate manufacturing is fixed on a turntable, the eccentric amount of a signal formed on the stamper is measured by an optical pickup head for eccentric amount measuring while rotating the turntable, the fixed position of the stamper on the turntable is controlled and corrected based on the data of the eccentric amount, and the eccentric amount of a machined inner and/or outer diameter hole is controlled to be within a specified range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for processing the inner diameter and / or outer diameter of a stamper for manufacturing an optical disk substrate,
The present invention relates to a stamper protective film for protecting a signal surface of a device and a stamper.

[0002]

2. Description of the Related Art In recent years, with the increase in the amount of information required for information equipment, audiovisual equipment, and the like, optical discs that are excellent in ease of data access, large-volume data storage, and miniaturization of equipment have been recorded. It is attracting attention as a medium and is being researched and developed. In general, optical disks are manufactured by injection compression molding using a stamper having pits or grooves formed on the surface to enable mass production.
At this time, the stamper has an inner diameter used as a fixing method to the molding machine when mounted on the optical disc substrate molding machine,
Alternatively, it is necessary to machine a hole having an outer diameter.

FIG. 1 is a sectional view of a conventional stamper processing apparatus for manufacturing an optical disk substrate. Hereinafter, a conventional stamper processing apparatus for manufacturing an optical disk substrate will be described with reference to this drawing.

A conventional stamper processing apparatus for manufacturing an optical disk substrate includes an upper blade 12 fixed downward and parallel to the surface of a stamper 11, and a lower blade installed on the lower surface of the stamper 11 so as to face the upper blade 12. 13 and the stamper 11 with the lower blade 13
A stamper fixing part 14 that slides while being fixed using a magnet, a vacuum or the like, and a sliding adjustment part 1 of the stamper fixing part 14
5, a rotary table 16 on which a stamper 11, a lower blade 13, a stamper fixing portion 14, and a slide adjusting portion 15 are mounted and which rotates around a rotation center axis A, and a white light which is installed perpendicularly to the surface of the stamper 11. The eccentricity amount photographing unit 17 for observing the eccentricity state of the signal unit on the stamper using the eccentricity amount, and the eccentricity amount monitoring unit 18 for outputting an image taken by the eccentricity amount photographing unit 17 as image data are installed. Have been.

Next, the operation of the conventional stamper processing apparatus for manufacturing an optical disk substrate will be described. First, the stamper 11 is placed at an arbitrary position on the lower blade 13 and is fixed by the stamper fixing portion 14. Subsequently, while rotating the rotary table 16, a boundary between a concentric signal formed on the stamper and a non-recording portion where no signal is recorded is photographed by using the eccentric amount photographing section 17, and the rotation table is rotated. 16 rotation center axes A
Is output to the eccentricity monitor 18 as a moving image at the boundary between the signal portion and the non-recording portion. In order that the movement width of the boundary between the signal portion and the non-recording portion becomes small on the eccentricity amount monitoring portion 18, 9
The position of the stamper 11 on the lower blade 13 is adjusted by using two slide adjusting portions 15 at an interval of 0 degrees, and the inner blade 1 of the upper blade 12 is adjusted.
The inner diameter hole and the outer diameter hole of the stamper 11 are machined by engaging the 2a, the outer diameter blade 12b, and the inner diameter blade 13a and the outer diameter blade 13b of the lower blade 13 with the opposing blades.

[0006]

However, in the prior art, a white light and a photographing lens having a low field magnification are used for the eccentric amount photographing section 17 and image data is used as an output of the eccentric amount monitoring section 18. Therefore, the resolution when measuring the amount of eccentricity is low, and the amount of eccentricity can be confirmed only at the limited position of the boundary between the signal area formed on the stamper and the unrecorded area where no signal is recorded. , Stamper 1
In some cases, depending on the depth of the signal recorded in No. 1, the imaging sensitivity of the eccentricity imaging unit 17 cannot be obtained. Also, since the resolution is low, the amount of eccentricity of each stamper 11 when a plurality of stampers are processed varies greatly, and the reproducibility and accuracy of the processing are limited. further,
Depending on the warpage of the stamper, the imaging focus of the eccentricity imaging unit 17 is deviated, and the accuracy of the eccentricity measurement is further reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has been made in consideration of the above problems, and has been made in consideration of the above-described problems. It is intended to provide a processing method, an apparatus and a protective film for a stamper.

[0008]

In order to solve the above problems, a stamper processing method for manufacturing an optical disk substrate according to the present invention includes a method of manufacturing a stamper for manufacturing an optical disk substrate having a substantially concentric signal formed on one side on a rotary table. And rotating the rotary table, and using an eccentricity measuring optical pickup head composed of at least one lens and a laser light source so that the emitted laser light has a focal point. Measuring the eccentricity of the rotary table with the substantially concentric signal on the stamper so as to have a focus on the signal surface recorded on the stamper; and A step of correcting while controlling the fixed position of the stamper on the rotary table, and machining an inner peripheral hole and / or an outer peripheral hole of the stamper Characterized in that it consists of degree.

Further, as a stamper processing apparatus for manufacturing an optical disk substrate of the present invention, an apparatus for processing the inner diameter and / or the outer diameter of a stamper for manufacturing an optical disk substrate having a signal formed on one surface, wherein the stamper is fixed. A rotary table having means, an eccentricity measurement optical pickup head including at least one or more lenses and a laser light source such that the emitted laser light has a focal point, and an inner periphery of the stamper, and / or Means for processing the outer periphery into a substantially circular shape, and the amount of eccentricity between the rotation center of the rotary table and a substantially concentric signal on the stamper is recorded on the stamper by rotating the rotary table. At the same time as the measurement by the optical pickup head for measuring the amount of eccentricity using a signal, the amount of eccentricity is within a predetermined range. The controls fixed position of the stamper on the rotary table while correcting, characterized by machining the inner peripheral hole and or the outer periphery hole in a substantially circular shape of the stamper by the processing means.

In one embodiment, the optical pickup head for measuring the amount of eccentricity has a wavelength of 350 nm to 700 nm.
Characterized by using a semiconductor laser.

In one embodiment, a YAG laser is used as a means for processing the inner peripheral hole and / or the outer peripheral hole of the stamper for manufacturing an optical disk substrate into a substantially circular shape.

Further, the stamper protective film of the present invention is characterized in that the thickness is formed so that the focal point of the optical pickup head for measuring the amount of eccentricity has on the stamper.

In still another embodiment, the stamper protective film is made of a material that is substantially transparent to the laser beam wavelength of the semiconductor laser of the optical pickup head for measuring the amount of eccentricity.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. As an embodiment,
A disk made of a metal material in which signal tracks consisting of concave and convex pits and grooves are spirally formed on one side as a stamper, and a material transparent to the laser beam of the optical pickup head for eccentricity measurement as a stamper protective film, and An example in which a YAG laser is used for inner and outer diameter processing will be described.

FIG. 2 shows a plan view and a cross-sectional view of a configuration of an inner and outer diameter processing device of a first optical disk substrate manufacturing stamper according to the present invention.

In FIG. 2, reference numeral 201 denotes a stamper fixing portion 202 which slides substantially parallel to the signal surface of the stamper 22 while fixing the stamper 22 using a magnet, vacuum or the like.
Sliding adjustment section 203 for sliding stamper fixing section 202
And a spring 204 for constantly pressing the stamper fixing portion 202 from the opposite side of the slide adjusting portion 203 toward the slide adjusting portion 203. With the surface on which the signal is formed facing upward, the stamper fixing portion 202
Is rotated via a rotary shaft 206 when the rotary table 201 is rotated by a spindle motor 205.

At this time, the eccentricity measuring optical pickup head 207 determines the eccentricity of the spiral signal formed on the stamper 22 with respect to the center of rotation of the rotary table, and places the eccentricity measuring optical pickup on the stamper. FIG. 3 shows a structural diagram in which the refractive index and the thickness are measured via the stamper protective film 208 in which the laser of the head is most narrowed.

First, P-polarized laser light emitted from a laser light source 301 for generating coherent laser light is shaped into substantially parallel light by a collimating lens 302, and the shaped laser light is polarized by a polarizing beam splitter 303. Only the components are transmitted. The P-polarized laser light transmitted through the polarization beam splitter 303 becomes circularly polarized light by passing through the quarter-wave plate 304. The laser light is made incident on the reproducing lens 305 and is narrowed down so as to have a focal point on the signal surface of the stamper 32 via the stamper protective film 306.

The laser beam reflected on the signal surface of the stamper 32 is reflected and enters the reproduction lens 305 again as circularly polarized light. The laser light emitted from the reproduction lens 305 passes through the quarter-wave plate 304 to become S-polarized light, is reflected in a substantially vertical direction by the polarization beam splitter 303, and is projected on the optical path 308 for the light receiving unit.

FIG. 4 shows a detailed structure of a laser light receiving portion for performing focus control so that the laser light emitted from the reproduction lens 305 has a focus on the signal surface of the stamper 32. The laser beam that has entered the polarization beam splitter 303 from the reproduction lens 305 and has been reflected in a substantially vertical direction is first detected by the detection lens 401 to have a laser beam diameter (X
And Y direction) are narrowed down as a whole. By providing the cylindrical lens 402 between the focal point 41a where the laser light is most narrowed down by the detection lens 401 and the detection lens 401, the X of the laser diameter narrowed down by the detection lens 401 is obtained.
Further narrow down only the direction, focus 4 of the cylindrical lens 402
2a results.

By having such a structure as the light path 308 for the light receiving section, when the relative distance between the signal surface of the stamper 32 and the reproducing lens 305 in FIG. 3 fluctuates, the laser diameter split by the polarizing beam splitter 303 becomes large or small. The focal position 41a of the detection lens 401 and the cylindrical lens 4
02, the position of the focal position 42a is changed, so that the light receiving element 40 divided into four at a predetermined position between the two focal points that fluctuates.
3 and the output voltage from the light receiving element [(43a + 43
b)-(43c + 43d)], it is possible to detect the relative distance between the signal surface of the stamper 32 in FIG.

The detected signal is fed back to the drive unit 307 of the reproducing lens 305 in FIG. 3 so as to be constant, so that the focal point of the laser beam emitted from the reproducing lens 305 is always on the signal surface of the stamper 32. The distance between the signal surface of the stamper 32 and the reproduction lens 305 is controlled. The laser light wavelength and the numerical aperture of the reproducing lens 305 are set so that the focal point of the laser light emitted from the reproducing lens 305 on the stamper 32 has one signal sequence as the spot size.

At this time, as the stamper 22 rotates, the focal spot of the laser beam on the stamper 22
During one rotation, signal tracks of the number (the amount of eccentricity of the signal on the stamper with respect to the rotation center of the rotary table 201 / the signal track pitch) are crossed. The amount of eccentricity of the signal formed on the stamper 22 with respect to the rotation center of the turntable 201 is measured using a tracking error signal generated when the signal track crosses the focal spot of the laser light.

A method of detecting a tracking error signal will be described with reference to FIG. FIG. 5 shows the configuration of a light receiving element 501 and a tracking error signal detection circuit 502 for calculating an image projected thereon and an output from the light receiving element. Four divided light receiving elements 51a, 51b, 5
The reproduction light spot scans the signal surface of the rotating stamper 22 on 1c and 51d, so that the reflected light image is projected. The projected image is in the signal column direction 503.
, And the difference between the light quantity changes is detected via the tracking error signal detection circuit 502.

In this case, for example, if the tracking error signal obtained from the tracking error signal detection circuit 502 is TE, and the light amounts detected from the light receiving elements 51a, 51b, 51c, 51d are A, B, C, D, respectively, TE = (A + C)-(B + D). By setting the tracking error signal TE to 0, the light receiving element 501
The scanning image of one signal track projected on the light receiving element 51
Therefore, the eccentricity of the signal on the stamper can be made smaller than the signal track pitch width.

Next, a structure for correcting the eccentricity of the stamper 22 with respect to the rotary table 201 will be described with reference to FIGS. 6 and 7A to 7C. FIG. 6 shows a rotary table 60.
1, a stamper fixing unit 602, a position detecting device 603 set on the outer periphery of the rotary table, a sliding adjusting unit 604, and an optical pickup head 605 for measuring the amount of eccentricity. Assuming that the stamper 606 fixed at an arbitrary position on the rotary table 601 is being rotated by the rotary table 601 in, for example, the direction of rotation 607, for example, FIG.
As shown in FIG. 7A, within the reproduction light spot 701 of the optical pickup head 605 for measuring the amount of eccentricity, the signal tracks 702 traverse the number shown in FIG. The signal output as a tracking error at this time is shown in FIG.
(B).

A tracking error is generated when the concave or convex portion of the signal on the stamper crosses the center of the reproduction light spot, and outputs 0 V as a voltage. When the concave or convex portion is farthest from the center of the reproduction light spot. Output the maximum value of the positive or negative voltage. This output signal is input to a pulsing circuit 209 for pulsing, and is provided so that the threshold levels H703 and L704 can be arbitrarily set according to the depth of the stamper formation signal. The pulsing circuit 209 is designed to output a pulse voltage when a tracking error crosses this threshold level. The output pulsed voltage is shown in FIG.

The output pulse signal is input to the eccentricity calculating device 210, and the position detecting device 603 monitors the tracking error signal for each rotation while observing one rotation cycle 705 of the tracking error signal. A motor driver that measures the amount of eccentricity of a signal on the stamper with respect to the rotation center of the turntable 201 and outputs a motor drive voltage for stamper position adjustment correction to the stamper sliding adjustment unit 203 according to the amount of eccentricity. A correction signal is output to 211. The stamper is a stamper sliding adjustment unit 203
Accordingly, the eccentricity of the signal on the stamper with respect to the rotation center of the turntable 201 is corrected so as to be equal to or less than the track pitch.

The stamper whose eccentricity has been corrected is installed substantially perpendicular to the surface of the stamper. Approximately 22mm
By using the YAG laser 212 installed at the two positions described above, the laser beam is emitted while rotating the rotary table 201, thereby cutting.

Table 1 shows that a stamper processing apparatus for manufacturing an optical disk substrate according to the present invention is used to form a stamper having a depth of about 0.6 μm on one surface and a signal row pitch of about 0.4 μm.
Signal is formed in a spiral shape, a disc made of nickel material produced by a method such as electroforming, a semiconductor laser having a wavelength of about 400 nm as a laser light source of an optical pickup for measuring eccentricity, and a light having a wavelength of about 400 nm as a stamper protective film. On the other hand, a protective film formed of a substantially transparent material and having a thickness of about 10 μm by a method such as spin coating is used, and a thickness of 280 is used.
This shows an example in which the eccentricity of the inner diameter and the outer diameter when four types of stampers of nm, 290 nm, 300 nm, and 310 nm are processed into an inner diameter φ22 and an outer diameter φ138 is measured by a microscope measuring instrument.

[0031]

[Table 1]

According to the present embodiment, as is apparent from Table 1, all stampers are processed so that the eccentricity of the punching diameter for the signal of the stamper is less than the signal row pitch for both the inner diameter and the outer diameter. Was completed.

In the stamper processing apparatus for manufacturing an optical disk substrate according to the above-described embodiment, in order to process the stamper into an inner diameter φ22 and an outer diameter φ138 as a YAG laser, the stamper is radially moved about 11 mm from the rotary table.
Although the description has been made using the means for installation at two positions of approximately 22 mm, for example, by setting the installation position of the YAG laser arbitrarily in the radial direction from the rotary table, the inner diameter and / or outer diameter of any stamper can be adjusted. It can also be processed.

Although the threshold levels H and L for pulsing the tracking error signal are set near the maximum value of the positive and negative voltage amplitudes of the tracking error, by setting them near 0 V, the punching hole diameter can be reduced. The amount of eccentricity can be further reduced with respect to the signal on the stamper.

Furthermore, as the protective film of the stamper, the thickness and the refractive index were selected so that the laser of the optical pickup head for measuring the eccentricity could be most narrowed on the stamper, but the thickness of the protective film was determined to a predetermined thickness. By installing a focus correction substrate between the optical pickup head for measuring eccentricity and the stamper, it is also possible to realize that the laser of the optical pickup head for measuring eccentricity is focused most on the signal surface of the stamper.

In the stamper processing apparatus for manufacturing an optical disk substrate according to the above-described embodiment, the laser light source of the optical pickup head for measuring the amount of eccentricity has a wavelength of about 400 nm.
Although the m type is used, the eccentricity can be measured by using a different laser wavelength depending on the signal recorded on the stamper.

[0037]

Since the present invention is constructed as described above, it has the following effects.

According to the present invention, the amount of eccentricity of the signal on the stamper with respect to the rotation center of the rotary table is measured while controlling the optical pickup head to always have the focus of the measurement laser on the signal surface on the stamper. Therefore, the eccentricity can be measured with high accuracy regardless of the warpage of the stamper, and the measurement spot can be reduced by using a laser. Therefore, the accuracy of the track width of the signal formed on the stamper can be improved. , The eccentricity can be adjusted, and the eccentricity can be measured without limiting the measurement location in the signal area. Further, since the data obtained by the eccentricity measurement is an electric signal, control and correction of the stamper position can be easily automated.

Further, by using a YAG laser as a means for processing the inner peripheral hole and / or the outer peripheral hole of the stamper for manufacturing an optical disk substrate into a substantially circular shape, the eccentricity measured by the eccentricity measuring optical pickup head can be obtained. Can be processed with Also, by forming a protective film on the stamper,
The signal can be protected from dust generated at the time of stamper processing and scratches during work.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a stamper processing apparatus for manufacturing an optical disk substrate according to a conventional technique.

FIG. 2 is a cross-sectional view of a stamper processing apparatus for manufacturing an optical disk substrate according to the present invention.

FIG. 3 is a cross-sectional view showing the relationship between the optical pickup for measuring the amount of eccentricity and the stamper of the stamper processing apparatus for manufacturing an optical disk substrate according to the present invention.

FIG. 4 is an optical path diagram for focus and tracking error detection of the optical pickup for measuring the amount of eccentricity of the stamper processing apparatus for manufacturing an optical disk substrate according to the present invention.

FIG. 5 is a light receiving element and a tracking error signal detection circuit diagram of an optical pickup for measuring the amount of eccentricity of the stamper processing apparatus for manufacturing an optical disk substrate according to the present invention.

FIG. 6 is a diagram showing the relationship between a stamper and an optical pickup for measuring the amount of eccentricity installed on a rotary table of a stamper processing apparatus for manufacturing an optical disk substrate according to the present invention.

FIG. 7 is a diagram showing a tracking error signal output from an optical pickup for measuring the amount of eccentricity of the stamper processing apparatus for manufacturing an optical disk substrate according to the present invention.

[Explanation of symbols]

 A Rotation center axis 11 Stamper 12, 12a, 12b Upper blade 13, 13a, 13b Lower blade 14 Stamper fixing unit 15 Sliding adjustment unit 16 Rotary table 17 Eccentric amount photographing unit 18 Eccentric amount monitoring unit 201 Rotary table 202 Stamper fixed Unit 203 Sliding adjustment unit 204 Spring 205 Spindle motor 206 Rotating shaft 207 Optical pickup head for measuring eccentricity 208 Stamper protective film 209 Pulser circuit 210 Eccentricity calculating device 211 Motor driver 212 YAG laser 301 Laser light source 302 Collimating lens 303 Polarizing beam splitter 304 1/4 wavelength plate 305 Reproduction lens 306 Stamper protection film 307 Reproduction lens drive unit 308 Light path for light receiving unit 401 Detection lens 41a Focus position of detection lens 402 Cylindrical lens 42a Focus position of cylindrical lens 403, 43a, 43b, 43c, 43d Light receiving element 501, 51a, 51b, 51c, 51d Light receiving element 502 Tracking error signal detection circuit 503 Signal column direction 601 Rotary table 602 Stamper fixing unit 603 Position detection device 604 Sliding adjustment unit 605 Eccentricity measurement optical pickup head 606 Stamper 607 Rotation direction 701 Reproduced light spot 702 Signal track 703 Threshold level H 704 Threshold level L 705 One rotation cycle

Claims (6)

[Claims] 1. A process of fixing a stamper for manufacturing an optical disc substrate having a substantially concentric signal formed on a surface thereof on a rotary table, and simultaneously rotating the rotary table so that the emitted laser light has a focal point. While using an optical pickup head for measuring the amount of eccentricity constituted by at least one or more lenses and a laser light source, while controlling so that the signal surface on the stamper always has the focal point of the laser light, A step of measuring the amount of eccentricity of a substantially concentric signal on the stamper with respect to the center of rotation using a signal recorded on the stamper, and controlling a fixed position of the stamper on the rotary table according to the eccentricity amount data While correcting, and the inner peripheral hole of the stamper,
Alternatively, a stamper processing method for manufacturing an optical disk substrate, comprising a step of processing an outer peripheral hole. 2. A device for processing an inner diameter and / or an outer diameter of a stamper for producing an optical disk substrate having a signal formed on a surface thereof, comprising: a rotary table having means for fixing the stamper; An optical pickup head for measuring the amount of eccentricity constituted by at least one or more lenses and a laser light source so that the stamper has a focal point; and a means for processing the inner periphery and / or the outer periphery of the stamper into a substantially circular shape. An optical pickup head for measuring the amount of eccentricity by using a signal recorded on the stamper to detect the amount of eccentricity of a substantially concentric signal on the stamper with respect to the center of rotation of the rotary table by rotating the rotary table. And at the same time, while controlling the fixed position of the stamper on the rotary table so that the amount of eccentricity is within a predetermined range, compensation is performed. And, the inner circumferential hole of the stamper by the processing means and or processing optical disc stamper processing apparatus characterized in that the substantially circular outer peripheral holes. 3. A laser light source for the optical pickup head for measuring the amount of eccentricity, which has a wavelength of 350 nm to 700 nm.
3. A semiconductor laser according to claim 2, wherein
4. The stamper processing apparatus for manufacturing an optical disk substrate according to claim 1. 4. A means for processing an inner peripheral hole and / or an outer peripheral hole of the stamper for producing an optical disk substrate into a substantially circular shape.
3. The stamper processing apparatus for manufacturing an optical disk substrate according to claim 2, wherein a YAG laser is used. 5. A laser beam emitted from the optical pickup head for measuring the amount of eccentricity, so that the laser beam has a focal point on a signal surface of a stamper for manufacturing an optical disk substrate having a substantially concentric signal formed on a surface thereof. A stamper protective film, wherein a predetermined thickness is formed on the signal surface of the stamper. 6. The stamper protective film according to claim 5, wherein a material that is substantially transparent to the laser light wavelength of the optical pickup head for measuring the amount of eccentricity is used.