JP2004164762A - Original disk exposing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable plotting a spiral pit column and groove for the center of an original disk even if the center of the original disk deviates from the rotation center. <P>SOLUTION: A turn table 3 is shifted in the direction of X (left and right direction) by a X stage drive mechanism 6 rotating an original disk 5 by the turn table 3, existence of the original disk is detected by an electronic detector 9 or a height detector 7, and the quantity of deviation of a center position of the original disk for a rotation center is obtained based on a X coordinate value when the electronic detector 9 or the height detector 7 starts to detect the disk surface and the value of a X coordinate when they start to detect only the disk surface. And the quantity of deviation of the center position of the original disk 5 for a rotation center of the turn table 3 and an electronic beam irradiation position are corrected in accordance with the rotation angle of the turn table 3, and digital information is plotted spirally for the center of the original disk. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a disc master exposure apparatus used for producing an optical disc master, and more particularly to a disc master exposure apparatus that detects a center of a master and corrects a drawing position according to the center position.
[0002]
[Prior art]
Optical discs such as CDs and DVDs are characterized by being portable, large-capacity recording media, and are widely used.
In order to manufacture an optical disk, for example, a disk for producing an optical disk master prepared by forming a resist layer on a glass substrate is prepared, and an optical disk master is prepared using the disk for manufacturing an optical disk master. It is necessary to produce a mold for producing an optical disc master using the above method.
Conventionally, the above-described optical disk master has been manufactured by irradiating a resist layer of a disk for manufacturing an optical disk master with a laser beam to form pits corresponding to digital information.
However, the recording density of the optical disk has been rapidly increasing, and the limitation of the recording density has been considered in the production of a master using laser light. For this reason, production of an optical disk master using an electron beam has been studied.
[0003]
As a technique for drawing on a rotating disk using a microbeam of light, electrons, ions, or the like, for example, a technique described in Patent Document 1 is known.
The technique disclosed in Patent Document 1 monitors a position shift of a rotation axis and corrects a writing beam position according to the amount of the shift in order to improve a decrease in drawing position accuracy due to wobbling of a center axis of a rotating disk. By doing so, high-precision drawing is performed.
Japanese Patent Application Laid-Open No. H11-163873 discloses an apparatus for irradiating an electron beam for a disc for producing an optical disc master, in which the dose per unit area of a pit formation portion is constant irrespective of the radial position of the disc for producing an optical disc master. In addition, there is disclosed a technique for correcting the eccentricity of the center of rotation of a disc for producing an optical disc master.
Also in the eccentricity correction described in Patent Document 2, similarly to that described in Patent Document 1, the rotation center of the disk for producing an optical disc master is eccentric due to mechanical vibration of a motor for rotating the disc for producing a master disc. Is corrected so that a highly accurate pit can be formed.
[0004]
[Patent Document 1]
JP-A-60-224160 [Patent Document 2]
Japanese Patent Application Laid-Open No. 2000-11464
[Problems to be solved by the invention]
An exposure apparatus using an electron beam, unlike a conventional apparatus using a laser, performs drawing on a disk for producing an optical disk master (hereinafter simply referred to as a disk master) in a vacuum atmosphere. For this reason, the loading and unloading of the master disc and the installation on the turntable use a load lock mechanism to protect the vacuum atmosphere.
However, it is difficult to easily and accurately set a sample such as a master disk on a turntable using a load lock mechanism, and a slight displacement may occur. In particular, some samples have a predetermined center, and it may take time and effort to accurately match them with the rotation center of the turntable in the mounting stage.
If the discrepancy between the center of the disc master mounted on the turntable and the center of rotation of the turntable is large, (1) it is necessary to newly measure and determine the drawing center of the drawing result (trajectory) in the process after drawing (2) The drawing result (trajectory) is entirely collapsed like an ellipse. Further, (3) the quality may be degraded, for example, the dose amount at the time of writing changes depending on the angular position of the master, and the line width and pit length change.
The present invention has been made in view of the above circumstances, the object of the present invention is, even if the rotation center of the turntable and the center of the disc master mounted on the turntable is displaced, with respect to the center of the disc master, It is an object of the present invention to enable pit rows and groups to be drawn in a spiral shape and to draw a high-quality master disk.
[0006]
[Means for Solving the Problems]
In order to solve the above problem, in the present invention, the rotation center of the disk master placed on the turntable is detected in advance, and based on the amount of deviation between the center of the disk master and the rotation center, the electron beam irradiation position is corrected, A pit row or the like corresponding to the center of the master is drawn.
That is, in the present invention, the electron beam irradiation position is corrected as follows.
(1) A turntable on which a disk master that is configured to be movable in at least one axial direction and is rotated by a spindle motor is mounted, and an electron beam that irradiates the disk master with an electron beam and draws digital information on the disk master. In the master disc exposure apparatus having irradiation means, an electron beam irradiation position deflection correction means for correcting the irradiation position of the electron beam is provided, and when the center position of the disc master is shifted with respect to the rotation center of the turntable, The electron beam irradiation position is corrected, and digital information is drawn spirally with respect to the center of the disk master.
(2) In the above (1), means for detecting the center of the master disc is provided.
(3) In the above (2), an electron beam and an electron detector for detecting a reflected electron or a secondary electron signal when the electron beam hits an object are used as means for detecting the center of the master disk.
(4) In the above (2), a height detector is used as means for detecting the center of the disk master.
The detection of the center position of the master disc by the output of the electronic detector or the height detector is performed, for example, as follows.
The turntable is moved in the X direction while rotating the disk master, and the presence or absence of the disk master at a predetermined position on the turntable is detected by an electronic detector or a height detector. The X coordinate value when the electronic detector or the height detector starts detecting the disk surface, and the X coordinate value when the electronic detector or the height detector starts detecting only the disk surface , The center position of the disk with respect to the rotation center is obtained.
(5) In the above (1) to (4), a rotation angle detecting mechanism such as a rotary encoder for detecting a rotation angle of the turntable is provided, and the electron beam irradiation position deflection correcting means is provided with a rotation center of the turntable and a disk. Based on the amount of deviation from the center of the master and the rotation angle of the turntable detected by the rotation angle detecting mechanism, the irradiation position of the electron beam is corrected, and digital information is spirally formed with respect to the center of the disk master. To draw.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the device of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram of an electron beam exposure apparatus to which the present invention is applied. An X stage 2 is installed in a vacuum chamber 1, and a turntable 3 rotated by a spindle motor 3a is mounted thereon. The X stage 2 is driven by an X stage driving device 6 and moves in the left-right direction in FIG. As a result, the turntable 3 also moves in the left-right direction in FIG.
The sample 5 (master disc) is housed in a sample holder 4, and the holder 4 is fixed to the turntable 3.
The exposure apparatus is provided with an electron gun 8 for irradiating an electron beam. In addition, a height detector 7 is attached for performing focus adjustment correction of the electron beam, and the height detector 7 is adjusted so that the measurement spot of the height detector 7 has an electron beam falling (irradiation) position.
An electron detector 9 is attached for monitoring when adjusting the electron beam, and an image as an electron microscope can be obtained by scanning the electron beam in the electron gun 8.
The actual drawing is performed by writing signal data spirally on the disk master 5 by slowly moving the X stage 2 while rotating the disk master 5.
[0008]
In order to control the position of the X stage 2, control the rotation of the turntable 3, and control the irradiation position by the electron gun 8, a control unit 10 is provided. 6, a drive signal to the electron gun 8 is output, and an output of the height detector 7, the output of the electron detector 9, an output of an encoder provided in the spindle motor 3a, and an X stage position signal are transmitted to the control unit. Sent to 10.
In order to control drawing on the disk master 5, the control unit 10 is provided with drawing control means 11.
The drawing control unit 11 is a unit for performing drawing control as described in Patent Document 2, for example. The irradiation position control unit 12 controls the irradiation position of the electron beam, and the disk master 5 is moved as described above. While rotating, the X stage 2 is slowly moved to perform control for spirally writing signal data on the master disk 5. In addition, the focus of the electron beam emitted from the electron gun 8 is adjusted by the output of the height detector 7, and the position of the electron beam irradiation is monitored based on the output of the electron detector 9 at the time of adjusting the electron beam. Or causes the monitor 13 to display an electron microscope image of the turntable surface. As described in Patent Documents 1 and 2, the drawing control means 11 may be provided with a function of correcting the eccentricity of the center of rotation of the disk master due to the mechanical vibration of the spindle motor 3a.
Further, in this embodiment, the control unit 10 includes a shift amount detecting unit 14 for detecting a shift amount between the rotation center and the center of the disc master, and a beam position deflection correcting unit 15 for correcting the beam irradiation position based on the shift amount. Is provided.
[0009]
FIG. 2 is a diagram showing a state of a master disk set on a turntable. As shown in FIG. 1, a disk master 5 is mounted on a sample holder 4, and the sample holder 4 is mounted on the turntable 3.
Here, for the sake of explanation, as shown in the figure, a hole 5a having a diameter of 30 mm and accurately drilled is provided in advance at the center of the disk master 5, and the rotation center of the turntable 3 and the center of the master are h. Assume that it is misaligned. The drawing is required to have a shape close to a concentric shape with the hole.
[0010]
Next, drawing on the master disk according to the present embodiment will be described.
First, the X stage 2 is moved so that the electron beam irradiation position comes near the center of rotation of the disk master 5.
An electron beam is emitted from the electron gun 8 while rotating the turntable 3 at an appropriate rotation speed, and the holder or the turntable surface below the master disk 5 is observed as an electron microscope image. At this time, in the X direction, the X stage 2 is moved by the X stage driving means 6 so that the center portion of the observation image becomes the center of rotation of the turntable 3, and the Y direction (the direction perpendicular to the plane of FIG. 1). Deflects the beam irradiated from the electron gun 8 by the irradiation position control means 12.
At this time, if the deflection correction amount in the Y direction is larger than the required accuracy, readjustment is performed so that the measurement point of the height detector 7 matches the electron beam fall (irradiation) position after the Y direction deflection correction. Keep it. By the above operation, the Y-coordinate component of the rotation center of the turntable 3 coincides with the electron beam falling (irradiation) position and the measurement point of the height detector 7.
[0011]
Next, referring to FIGS. 3, 4 and 5, a method of measuring the amount of deviation between the center of rotation of the turntable 3 and the center of the master disc 5 using the electron beam and the electron detector 9 will be described. 3 and 4 show a change in the output of the electron detector 9 when the X stage 2 is moved while rotating the turntable 2, and FIG. 5 shows a change in the position of the hole in the master disc 5. .
Here, the coordinate value of the X stage 2 determined by the operation up to this point is set to X0. At this time, the locus of the center of the disc master 5 is as shown by the solid line in the figure, and the position of the hole when the X coordinate value of the center of the disc master is X0 is as shown by the thick solid line in the figure. When the X stage 2 is moved while rotating the disk master 5, the positions of the holes in the disk master 5 change as indicated by the dotted lines in FIG.
When the coordinate value of the X stage 2 is X0, the detection point of the electronic detector 9 is a hole of the master disc 5. When the electron beam is irradiated on the hole portion and the master portion, there is a difference in the level of the electron detector 9 due to the difference in the charging state of the material.
[0012]
When the X stage 2 is slowly moved (for example, to the right in FIG. 1) while the turntable 3 is being rotated, the output of the electron detector 9 becomes (a) and (a) in FIGS. b), (c), and (d).
That is, from the state in which the master surface is not detected as shown in (a), the detection of the master surface is started as shown in (b), and the state is such that the master surface and the hole are detected as shown in (c), Further, as shown in (d), the state changes so as to detect only the master surface.
Here, the X stage coordinate when starting to detect the disk master surface as shown in FIG. 3 (b) is X1, and the X stage when starting to detect only the disk master surface as shown in FIG. 4 (d). Assuming that the coordinates are X2, as is clear from FIG. 5, the X coordinate value of the center of the master is X0 = (X2 + X1-30) / 2, and the displacement h between the center of the master disk and the center of rotation is (X2-X1) / It becomes 2.
The shift amount detecting means 14 shown in FIG. 1 calculates the X-stage coordinate at the time of starting to detect the surface of the master disc from the output of the electronic detector 9 and the X-coordinate value of the X-stage 2 as described above, The X stage coordinates when only the master surface is started to be detected is determined as X2, and from this, the X coordinate value X0 of the center of the master disk and the displacement h between the center of the master disk and the rotation center are calculated.
[0013]
Next, correction of the beam irradiation position based on the displacement amount h will be described.
It is assumed that the relationship between the rotation angle of the turntable 3 and the deviation h between the center of the disk master 5 and the rotation center is as shown in FIG.
At this time, in accordance with the rotation angle θ of the turntable 3, the center position of the master disc 5 is shifted from the rotation center by hcos θ in the Y direction and hsin θ in the X direction, as shown in FIG.
Therefore, the position correction of the electron beam may be performed by hcos θ for the displacement in the Y direction and hsin θ for the displacement in the X direction.
The beam position deflection correcting means 15 shown in FIG. 1 obtains the rotation angle θ of the turntable 3 from the output of the encoder provided in the spindle motor 3a, and calculates the rotation angle θ and the deviation amount detected by the deviation amount detecting means 14. Based on h, the position correction amount of the electron beam is obtained as described above, and an electron beam irradiation position correction signal is output to the irradiation position control means 12.
This makes it possible to draw a spiral pit row with respect to the center of the disk master to be drawn.
[0014]
By the way, usually, it is often the case that it is not desired to irradiate an unnecessary electron beam to the disk master surface.
Therefore, if it is known that the center of rotation of the turntable 3 is coincident with the electron beam irradiation position and the Y coordinate component of the measurement point of the height detector 7, the height detector 7 performs the same operation as described above. Thus, the amount of deviation of the center position of the master disc can be obtained.
7 and 8 show how the output of the height detector 7 changes in the process of obtaining the displacement h between the center of the disc master and the center of rotation.
When the hole is detected, the output of the detector is in a saturated state because it is far from the surface of the board. As the order of (a), (b), (c), and (d) of FIGS. 7 and 8 is followed, the detection amount of the master surface increases. That is, from the state in which the master surface is not detected as shown in (a), the detection of the master surface is started as shown in (b), and the state is such that the master surface and the hole are detected as shown in (c), Further, as shown in (d), the state changes so as to detect only the master surface. Note that the gradual change in the output in (d) is due to the undulation of the master.
From the change in the height detector 7, a shift amount h between the center of the disc master and the center of rotation can be obtained in the same manner as in the case where the electronic detector 9 is used. The electron beam position can be corrected.
[0015]
【The invention's effect】
As described above, according to the present invention, even if the center of the disc master does not coincide with the rotation center of the turntable, it is possible to draw a pit row or groove spirally with respect to the center of the master. Become. For this reason, it is possible to draw a high-quality master that is advantageous for the subsequent steps.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of an electron beam exposure apparatus to which the present invention is applied.
FIG. 2 is a diagram showing a state of a disc master placed on a turntable.
FIG. 3 is a diagram (1) illustrating a change in the output of the electron detector when the X stage is moved while rotating the disk master.
FIG. 4 is a diagram (2) illustrating a change in the output of the electron detector when the X stage is moved while rotating the disk master.
FIG. 5 is a diagram for explaining how to determine the center of a master disc.
FIG. 6 is a diagram showing a relationship between a rotation center and a disc master disc center.
FIG. 7 is a diagram (1) illustrating a change in height detector output when the X stage is moved while rotating the disk master.
FIG. 8 is a diagram (2) illustrating a change in the output of the height detector when the X stage is moved while rotating the disk master.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 X stage 3 Rotary stage 3a Spindle motor 4 Sample holder 5 Sample (master disk)
6 X stage driving device 7 Height detector 8 Electron gun 9 Electron detector 10 Control unit 11 Drawing control unit 12 Irradiation position control unit 13 Monitor 14 Deviation amount detection unit 15 Beam position deflection correction unit

Claims (5)

A turntable on which a disc master is placed, the turntable being configured to be movable in at least one axial direction and rotated by a spindle motor;
Irradiating the disk master with an electron beam, and electron beam irradiation means for drawing digital information on the disk master, a disk master exposure apparatus,
An electron beam irradiation position deflection correction means for correcting the irradiation position of the electron beam,
The electron beam irradiation position deflection correction means corrects the electron beam irradiation position when the center position of the disc master is shifted with respect to the rotation center of the turntable, and spirally moves with respect to the center of the disc master. An original disc exposure apparatus for drawing digital information. 2. An apparatus according to claim 1, further comprising means for detecting a center of said master disk. 3. An apparatus according to claim 2, wherein an electronic detector is used as means for detecting the center of said disk master. 3. An apparatus according to claim 2, wherein a height detector is used as means for detecting the center of said master disk. Equipped with a rotation angle detection mechanism that detects the rotation angle of the turntable,
The electron beam irradiation position deflection correction means, based on the amount of deviation between the rotation center of the turntable and the center of the disc master, and the rotation angle of the turntable detected by the rotation angle detection mechanism, determines the irradiation position of the electron beam. 5. The disk master exposure apparatus according to claim 1, wherein the digital information is drawn spirally with respect to the center of the disk master.

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