JP2008123590A - Patterning disc eccentricity measuring apparatus and eccentricity measuring method - Google Patents

Abstract

An object of the present invention is to provide a measuring apparatus that can measure the amount of eccentricity with high accuracy even if the recording pattern of a patterning disk is miniaturized, and that uses a conventional image processing technique without using an expensive and complicated apparatus. A patterning disk eccentricity measuring device capable of measuring the eccentricity of the patterning disk with only a small change is obtained.
An illumination light source that emits illumination light, a lens that is a first optical system that collects the illumination light and irradiates the patterning disk, and a diffracted light reflected from the patterning disk are collected. The second optical system 103 including the objective lens 106 and the sensor unit 105 that detects the diffracted light 110 collected by the second optical system 103, and the light of the lens 102 that is the first optical system. The axis and the optical axis of the second optical system 103 have a predetermined angle. The predetermined angle indicates that the 0th-order light 109 is not incident on the second optical system 103 but the diffracted light 110 is incident. A patterning disk eccentricity measuring apparatus 100 as a feature.
[Selection] Figure 1

Description

  The present invention relates to a patterning disc eccentricity measuring device and the like, and more particularly to a patterning disc eccentricity measuring device and the like capable of measuring the amount of eccentricity with high accuracy even when a recording pattern of a patterning disc is miniaturized.

A patterning disc such as a CD or DVD that is a disc-shaped recording medium has a recording area in which a recording pattern is formed by grooves or pits in a concentric or spiral shape.
The disk rotates mechanically during recording / playback, but the center of the rotation axis and the center of the recording area are not necessarily the same point, and the difference between the center of the rotation axis and the center of the recording area is the amount of eccentricity of the patterning disk. It is called.

  In a patterned disk such as an optical disk or a magneto-optical disk, if the amount of eccentricity is large, there is a possibility that a problem occurs in recording / reproducing characteristics or that tracking becomes impossible. For this reason, in various patterning discs, the upper limit of the eccentric amount is strictly defined in the standard.

  The causes of eccentricity of the patterning disc include those due to stampers during production, those due to settings during injection molding, those due to bonding of substrates, and those due to adhesion between the substrate and the hub. There are various reasons depending on the variety and manufacturing process.

  The eccentricity of the patterning disk generated for the above reasons leads to the problem of inducing the deterioration of the tracking accuracy of the light spot with respect to the target track, the deterioration of the signal recording / reproduction quality, and the deterioration of the track following performance, In the worst case, a recording / reproducing error may occur.

  In order to prevent these phenomena, it is a very important issue to grasp the eccentricity of the manufactured disk in the state of the substrate or the disk.

As an example of a method for measuring the amount of eccentricity of the patterning disk, there is a method for measuring based on a tracking error signal such as a push-pull signal.
In this method, an optical disk is attached to a rotating mechanism such as a spindle motor and rotated, and a tracking error signal is detected by an optical head. Since the light beam irradiated from the optical head crosses a plurality of tracks as recording patterns according to the eccentricity when the optical disk rotates, the wave number corresponding to the eccentricity is observed. In this way, the wave number per rotation is counted, and the eccentricity can be obtained from the counted wave number.

However, in this method, it is necessary to focus on the recording pattern composed of pits and grooves existing on the patterning disk by using a laser and actually follow the locus of the grooves, etc., and the apparatus configuration is complicated and expensive. I needed it.
Moreover, in order to detect a tracking error signal, it must be completed as a patterning disk, and measurement cannot be performed in a substrate state without a reflective film.

On the other hand, there is a method in which the amount of eccentricity is obtained by measuring the boundary portion by utilizing the difference in brightness between the mirror portion having no groove and the groove portion where the groove exists by an image processing method.
FIG. 8 is a diagram showing an eccentricity measuring apparatus for a patterning disk that uses a difference in brightness between a mirror part without a groove and a groove part where a groove exists to measure the boundary and determine the amount of eccentricity by an image processing method. It is.
The eccentricity measuring apparatus 800 focuses an illumination light source 801 that emits illumination light, a lens 802 that collects illumination light emitted from the illumination light source 801, and the illumination light collected by the lens 802 on the patterning disk 804. In addition, the objective lens 803 that condenses the zero-order light and the diffracted light reflected from the patterning disk 804, the mirror 805 that reflects the zero-order light and the diffracted light collected by the objective lens 803, and the mirror 805 reflect the light. It is composed of a lens 806 that condenses zero-order light and diffracted light on a sensor unit 807 such as a camera.

  As shown in FIG. 8A, when the illumination light is applied to the mirror unit 808 of the patterning disk 804, the illumination light is reflected by the mirror unit 808, and the zero-order light is the objective according to the reflectance of the observation surface. Return to the lens 803. The zero-order light is changed in direction by a mirror 805 and observed by a sensor unit 807 such as a camera.

  On the other hand, when the illumination light is applied to the groove 809 of the patterning disk 804, the irradiation light is reflected by the patterning disk 804 as shown in FIG. 8B, and zero-order light corresponding to the reflectance of the observation surface. Then, the diffracted light 810 generated in the groove 809 returns to the objective lens 803. For this reason, when the groove 809 is observed, the 0th-order light and the diffracted light 810 interfere with each other, and the image is observed darker than the mirror part of only the 0th-order light. By confirming the difference in contrast with the sensor unit 807, the boundary between the mirror unit 808 and the groove unit 809 can be determined.

When this apparatus is used, measurement is possible even in a substrate state without a reflective film, and measurement can also be performed with transmitted light. In addition, this apparatus only needs to have a simple mechanism such as a microscope and a mechanism capable of measuring the position, and the apparatus is simple and inexpensive.
With conventional patterning discs, since the groove width is wide and the groove is deep, the difference in the amount of light between the mirror part and the groove part is large and clear contrast is obtained, so there is no problem in determining the boundary, and this device is very easy Measurement was possible.

However, with the recent increase in the density of patterning disks, the interval between the grooves is narrowed, and the groove width itself is becoming narrower. For example, the groove width (track pitch) of a conventional DVD (Digital Versatile Disc) is 0.74 μm, but the HD DVD (High-Definition Digital Versatile Disc), which is the next generation optical disc, is narrow to 0.4 μm. It has become.
In addition, the groove depth tends to become shallower as the recording / reproducing laser has a shorter wavelength. This means that a recording pattern such as a groove serving as a diffraction grating becomes smaller, and the period of the diffraction grating becomes finer.
When the period of the diffraction grating is fine, the diffraction grating diffracts at a large angle with respect to the zero-order light, and conversely, when the period is coarse, diffraction occurs at a small angle.

FIG. 9 is a diagram illustrating the diffracted light generated when the groove portion is observed when the groove period of the patterning disk becomes fine.
In the above-described FIG. 8 (B), the sufficiently small angle alpha ₁ of the diffracted light 810 with respect to the center line of the 0-order light, diffracted light 810 and 0-order light enters the objective lens 803, the return light interfere. However, when a patterning disk having a groove shape finer than the conventional one is observed as shown in FIG. 9, the angle α ₂ is larger than the 0th-order light when the light irradiated to the measurement portion is diffracted by the groove portion. Thus, the diffracted light 901 escapes out of the objective lens 803 and is not incident on the objective lens 803.
As a result, the zero-order light and the diffracted light do not interfere with each other, and the obtained image is only the zero-order light. Eventually, it is not so dark as compared with the case where the mirror portion is observed, and sufficient contrast cannot be obtained, so that it is impossible to distinguish between the mirror portion and the groove portion.

  As a device for measuring the eccentricity of a patterning disk that can solve this problem, a laser is applied from a laser oscillator onto a pattern formed on a disk-shaped object while being mounted on a rotating mechanism that rotates and holds the disk-shaped object. An eccentricity adjusting device is disclosed in which first-order diffracted light that is irradiated with a beam and diffracted by a pattern formed on a disk-like object is captured by an optical position sensor unit, and the amount of eccentricity is calculated (for example, Patent Document 1). reference.).

JP-A-6-4891

  However, since the eccentricity adjusting device disclosed in Japanese Patent Laid-Open No. 6-4891 has a configuration using laser light, the configuration of the device is complicated and expensive, and only a small change of a conventionally used device is required. It is not something that can be used. In addition, there is a problem that it is difficult to align the optical sensor unit that receives the first-order diffracted light.

  The present invention has been made in view of the above-described various problems of the prior art, and the object of the present invention is to reduce the size of a recording pattern composed of grooves and pitches of a patterning disk. An object of the present invention is to provide a patterning disk eccentricity measuring device capable of measuring the eccentricity with high accuracy.

  Another object of the present invention is to provide a method for measuring the eccentricity of a patterning disk, which is composed of grooves and pitches of the patterning disk and can measure the amount of eccentricity with high accuracy even if the recording pattern is miniaturized.

  As a result of intensive studies, the present inventors have discovered that even if the groove width is narrow in a patterning disc such as a next generation optical disc or a blue laser compatible optical disc in which the laser wavelength for recording / reproducing is shorter than before, an expensive and complicated apparatus Succeeded in developing an eccentricity measuring device and the like that can discriminate the boundary portion where the mirror portion and the groove portion exist without using a mirror and can measure the eccentricity amount of the patterning disk with high accuracy, and completed the present invention. It was. That is, this invention makes the following a summary.

  That is, according to the present invention, the illumination light source that emits the illumination light, the first optical system that collects the illumination light and irradiates the patterning disk, and the second that collects the diffracted light reflected from the patterning disk. An optical system, and a sensor unit that detects diffracted light collected by the second optical system, and the optical axis of the first optical system and the optical axis of the second optical system have a predetermined angle. In addition, there is provided an eccentricity measuring apparatus for a patterning disk, wherein the predetermined angle is an angle at which zero-order light does not enter the second optical system but diffracted light enters.

Here, the diffracted light is preferably first-order diffracted light.
In addition, the rotation mechanism unit that holds and rotates the patterning disk and the relative position of the rotation mechanism unit without shifting the positional relationship between the illumination light source, the first optical system, the second optical system, and the sensor unit. A moving mechanism unit that moves the light source, a light source for illumination, a first optical system, a second optical system, a position detection mechanism unit that detects a relative position between the sensor unit and the rotation mechanism unit, and a groove portion of the patterning disk, It is preferable to further include a discriminating mechanism that discriminates from the mirror unit, and the discriminating mechanism converts the diffracted light detected by the sensor unit into an electric signal and determines the strength of the electric signal by setting a threshold value. By doing so, it is preferable to distinguish the groove portion and the mirror portion of the patterning disk.
The patterning disc further includes: a second illumination light source that emits illumination light; and a third optical system that collects the illumination light emitted from the second illumination light source and irradiates the patterning disc. More preferably, the second-order optical system collects zero-order light reflected from the patterning disk out of the illumination light irradiated on.

  On the other hand, according to the present invention, the illumination light source that emits the illumination light, the light shielding plate that selectively blocks the illumination light that directly enters the patterning disk out of the illumination light, and the first light that collects the illumination light and irradiates the patterning disk. 1 having an optical system, a second optical system that collects diffracted light that has been transmitted through the patterning disk and diffracted, and a sensor unit that detects the diffracted light collected by the second optical system. An eccentricity measuring device for a patterning disk is provided.

  Here, the diffracted light is preferably first-order diffracted light, and the illumination light applied to the patterning disk by the first optical system is more preferably applied as pseudo dark field illumination.

  Further, according to the present invention, the illumination light emitted from the illumination light source is condensed by the first optical system, irradiated to the patterning disk, and the diffracted light reflected from the patterning disk is collected by the second optical system. There is provided a method for measuring the eccentricity of a patterning disk, wherein the eccentricity of the patterning disk is measured by detecting diffracted light that is emitted and collected by a second optical system.

  ADVANTAGE OF THE INVENTION According to this invention, even if the recording pattern of a patterning disc refines | miniaturizes, the eccentricity measuring apparatus of the patterning disc which can measure the amount of eccentricity with high precision can be obtained.

  Hereinafter, the best mode for carrying out the present invention (embodiment) will be described in detail. However, the present invention is not limited to the following embodiment, and various modifications may be made within the scope of the gist of the present invention. Can be implemented.

  As a result of intensive studies, the present inventors have devised the position of the illumination light source that irradiates the patterning disk, focusing on the fact that the current problem is a change in the angle of the diffracted light due to the miniaturization of the recording pattern of the patterning disk. .

  That is, the illumination light that was incident at about 90 degrees on the surface of the patterning disk, which is a conventional observation portion, was intentionally incident obliquely. At this time, the objective lens is set to a position where the 0th-order light reflected from the patterning disk does not enter, and an angle at which only diffracted light of the reflected illumination light enters the objective lens in consideration of the known groove shape of the disk. .

FIG. 1 is a diagram showing an example of the configuration of a patterning disk eccentricity measuring apparatus to which the present embodiment is applied.
A patterning disc eccentricity measuring apparatus 100 shown in FIG. 1 is a lens 102 that is a first optical system that focuses an illumination light source 101 and illumination light emitted from the illumination light source 101 to focus on the patterning disc 104. The second optical system 103 collects the diffracted light reflected from the patterning disk 104 and guides it to the sensor unit 105, and the sensor unit 105 such as a camera that detects the diffracted light.
The second optical system 103 includes an objective lens 106.

When the mirror portion 107 of the patterning disc 104 is observed with this apparatus, the light reflected by the patterning disc 104 does not enter the objective lens 106 as shown in FIG. Neither the light 109 nor the diffracted light 110 is observed, resulting in a very dark image.
On the other hand, when the groove 108 of the patterning disk 104 is observed with this apparatus, as shown in FIG. 1B, the 0th-order light 109 reflected by the patterning disk 104 is not observed, but the diffracted light 110 is applied to the objective lens 106. By entering the light, a brighter image is observed than when the mirror unit 107 is observed. The boundary between the mirror part 107 and the groove part 108 is discriminated based on the difference in brightness, and the eccentric amount of the patterning disk 104 having the narrow or shallow groove part 108 that could not be observed so far can be measured.

In this apparatus, the relative angle between the illumination light source 101 and the objective lens 106, that is, the relationship between the lens 102 as the first optical system and the second optical system 103 adjusts the relative angle of the optical axis. However, it is sufficient that the diffracted light 110 is incident on the objective lens 106 but the 0th-order light 109 is not incident, and even if the illumination light incident from the lens 102 as the first optical system is incident obliquely, The second optical system 103 side may be tilted.
However, in consideration of adjustment of equipment such as optical axis alignment, it is preferable to have a structure in which the second optical system 103 side is fixed and the position of the lens 102 as the first optical system can be adjusted.

The order of the diffracted light to be observed is not particularly selected, but ± 1st order diffracted light occupies about 4% of 0th order light and is brighter than ± 2nd order diffracted light and ± 3rd order diffracted light. It is optimal for use in disc eccentricity measuring devices.
Even if diffracted light after ± 2nd order diffracted light is incident, it can be distinguished because it is darker than ± 1st order diffracted light. Further, by simultaneously observing the 0th order light, it is possible to roughly determine that the observation light is the 1st order diffracted light and the incident angle of the irradiation light.
In the present specification, the first-order diffracted light is meant to include both + 1st-order diffracted light and −1st-order diffracted light. The same applies to the meanings of second-order diffracted light and third-order diffracted light.

  The relative angle formed by the optical axes of the first optical system and the second optical system can be calculated from the diffraction grating shape formed by the groove of the patterning disk, but experimentally. You can ask for it.

  The light source 101 for illumination is not particularly limited, but a light source such as a ring-shaped LED illumination, a ring-shaped fluorescent lamp, or a dome-shaped LED illumination has a large area, Since both the diffracted light 110 easily enters the objective lens 106, it is not preferable. Therefore, a point light source that emits illumination light from a small area is preferable. A white light source is preferable, and an example of such an illumination light source 101 is a halogen lamp.

FIG. 2 is an explanatory diagram in the case of discriminating the mirror part and the groove part of the patterning disk using the measuring apparatus of FIG.
On one patterning disk 201 in which the mirror part and the groove part exist, the patterning disk is not shifted without shifting the positional relationship between the illumination light source 101, the lens 102 as the first optical system, the second optical system 103, and the sensor part 105. Scanning is performed from the mirror portion to the grooved direction so as to pass through the center of the spindle rotation axis 201.
In this case, since a change in the amount of light captured by the sensor unit 105 occurs at the boundary between the mirror portion and the groove portion, the position where the change in the light amount can be confirmed is the boundary 202 between the mirror portion and the groove portion.
If the amount of movement of the objective lens 106 and the illumination light source 101 or the amount of movement of the disc can be grasped, the eccentricity measurement of the pattern with respect to the rotation axis can be performed.

FIG. 3 is a diagram showing another example of the configuration of a patterning disc eccentricity measuring apparatus to which the present embodiment can be applied.
The patterning disc eccentricity measuring apparatus 300 shown in FIG. 3 includes, in addition to the patterning disc eccentricity measuring apparatus 100 shown in FIG. 1, a rotation mechanism 301 that holds and rotates the patterning disc 304, and the optical system 100. And a position detecting mechanism 302 that detects the position of the optical system 100.

Here, the “optical system 100” is a portion corresponding to the eccentricity measuring apparatus 100 for the patterning disk shown in FIG. 1, and the following description will be made in other words as “optical system 100”.
The rotation mechanism unit 301 has a spindle unit 303, can hold the patterning disk 304 on the spindle unit 303, and can rotate. The spindle unit 303 may be provided with a function of grasping the rotation angle such as a rotary encoder. The rotation control unit 305 controls the angle of the spindle unit 303, and the angle information is manually input.
The optical system 100 can be moved by a moving mechanism unit (not shown), and the position detecting mechanism unit 302 can measure the position.
For the position detection mechanism 302, for example, a linear scale can be used. Further, the value measured on the scale may be displayed on the counter 306.
The coordinates of the optical system 100 measured by the position detection mechanism 302 can be easily calculated if the position of the central axis of the spindle 303 is set to 0, for example.

When the eccentricity measuring apparatus 300 for the patterning disk 304 as shown in FIG. 3 is used and scanning is performed with the position of the central axis of the spindle unit 303 set to 0 (origin), the sensor unit in which light is a camera in the mirror unit Cannot be observed on the monitor 307 that projects the image of the camera.
When the observation portion reaches the groove on the patterning disk 304, diffracted light enters, and a bright / dark boundary is observed on the monitor 307. The center of the monitor is marked, and the distance from the position of the central axis of the spindle unit 303 is measured and recorded by the position detection mechanism unit 302.

Next, the same operation is repeated by rotating the angle of the spindle 303 by 180 degrees. If the first measured coordinate is X1 and the second coordinate measured by rotating 180 degrees is X2, (| (X1-X2) |) / 2 is a deviation in the X direction.
Similarly, the angle of the spindle 303 is measured at 90 degrees and 270 degrees, and the deviation in the Y direction is calculated by calculating (| (Y1-Y2) |) / 2 from the measured values Y1 and Y2. it can.

FIG. 4 is a diagram for explaining the positions of X1, X2, Y1, and Y2 when a patterning disc having eccentricity is measured.
If X1> X2, the center of the groove area in the X direction in FIG. 4 is to the right of the Y axis. If X2> X1, the center of the groove or pit area in the X direction is to the left of the Y axis. It is in.
If X1 = X2, the groove area of the disk in the X direction and the center of the rotating shaft are equal, and there is no eccentricity in the X direction.
If Y1> Y2, the center of the groove area in the Y direction in FIG. 4 is above the X axis, and if Y2> Y1, the center of the groove section in the Y direction is below the X axis.
If Y1 = Y2, the area of the groove portion of the disk in the Y direction and the center of the rotating shaft are equal, and there is no eccentricity in the Y direction.

  And the distance from the center of a rotating shaft to the area center of a groove part is computable with the following formula | equation.

  By the above method, it is possible to measure the eccentricity of a disk having a fine pattern that could not be measured so far.

  In the above method, coordinates are measured by measuring four points, but three-point measurement or five-point measurement is performed, a circle passing through the points is calculated by computer calculation, and the center coordinates of the user area are calculated. It is also possible to measure the amount of eccentricity with respect to the center of the rotation axis of the spindle unit set first.

Further, although the rotation control unit 305 controls the angle of the spindle unit 303 in the rotation mechanism unit 301, it may be performed manually.
In the above example, the moving mechanism unit (not shown) moves the optical system 100. However, the moving mechanism unit may move the rotating mechanism unit 301.

  In the above example, for simple configuration, boundary determination, recording area position calculation, disk angle information input, boundary determination and alignment are performed manually while looking at the monitor 307. It is also possible to leave it to the device.

FIG. 5 is a diagram showing another example of the configuration of the eccentricity measuring apparatus for the patterning disk to which the present embodiment can be applied in such a case.
The patterning disc eccentricity measuring apparatus 500 shown in FIG. 5 inputs the information of the counter 306 and the information from the camera to the patterning disc eccentricity measuring apparatus 300 of FIG. A discrimination mechanism unit 501 having a discrimination function is added.
When a difference in brightness is observed on the monitor 307 at the boundary between the mirror portion and the groove portion, the discrimination mechanism unit 501 discriminates the boundary point between light and darkness by image processing, and takes the coordinates from the counter 306 to obtain the mirror portion. The coordinates of the boundary of the groove can be measured.
In this case, it is preferable to perform measurement in conjunction with the rotation control unit 305, and all may be performed together in one control device.
Further, without using image processing, it is possible to switch the camera to a photo detector, discriminate the boundary with an electric signal, and measure the coordinates of the boundary point with the counter 306. In this case, the discriminating mechanism unit 501 discriminates the groove portion and the mirror portion of the patterning disc 304 by converting the diffracted light detected by the sensor unit into an electric signal and determining the strength of the electric signal by setting a threshold value. Will do.
After measuring the coordinates of the boundary point, the same measurement result can be obtained by causing the computer to execute the same calculation as described above.

  On the other hand, in particular, when measuring the amount of eccentricity of a plastic patterning disk, it is very difficult to focus because of tilt, waviness of the disk itself, and uneven thickness. However, highly reliable measurement cannot be performed unless measurement is performed with just focus.

  However, since the measurement apparatus described so far performs dark field observation using diffracted light, it is necessary to focus in a dark image state. In such a case, the focus is not accurately adjusted and the image is blurred. As a result, it is difficult to determine the boundary between the mirror part and the groove part, and there is a possibility that accurate measurement cannot be performed.

FIG. 6 is a diagram showing another example of the configuration of the eccentricity measuring apparatus for the patterning disk to which the present embodiment can be applied in such a case.
The patterning disc eccentricity measuring apparatus 600 shown in FIG. 6 is emitted from the second illumination light source 601 and the second illumination light source 601 with respect to the patterning disc eccentricity measuring apparatus 100 described in FIG. A lens 602 which is a third optical system for condensing the illumination light is newly provided.
Illumination light emitted from the second illumination light source 601 is collected by the lens 602 and irradiated to the patterning disk 104 through the objective lens 106. The light reflected from the patterning disk 104 is collected again by the objective lens 106, reflected by the mirror 603, collected by the lens 604, and enters the sensor unit 105.
By using this configuration, the observation surface is brightly illuminated, and the focus adjustment of the observation surface becomes easy. Further, since bright lines are observed at the boundary between the mirror part and the groove part of the patterning disk 104, the discrimination is possible.

By the way, in the present embodiment, if the configuration is such that the 0th-order light out of the light reflected by the patterning disk is not incident on the objective lens but the diffracted light is incident on the objective lens, a patterning disk eccentricity measuring device is sufficient.
Therefore, instead of the apparatus configuration described so far, as another example, for example, a dark field illumination that is the same illumination method as a microscope called an ultramicroscope or a dark field microscope is used, and a ring slit that blocks the central portion is used. A configuration in which the 0th-order light is not incident on the objective lens by using a method such as the above may be employed.

FIG. 7 is a diagram showing an example of a patterning disk eccentricity measuring apparatus to which the present embodiment can be applied in such a case.
The patterning disc eccentricity measuring apparatus 700 shown in FIG. 7A is positioned between an illumination light source 701 (not shown) that emits illumination light, and between the patterning disc 704 and the illumination light source 701, and out of the illumination light to the patterning disc 704. A light shielding plate 702 that selectively blocks directly incident illumination light, and is positioned between the patterning disk 704 and the light shielding plate 702 and collects illumination light that passes outside the illumination light blocked by the light shielding plate 702 and irradiates the patterning disk 704. A first optical system 703, a second optical system 705 that condenses the diffracted light 709 transmitted through the patterning disk 704, and a sensor such as a camera that detects the diffracted light collected by the second optical system 705 Part 706 is provided. The second optical system 705 may include an objective lens 707, and a diaphragm 708 may be provided between the patterning disk 704 and the illumination light source 701.
FIG. 7B shows the arrangement of the light shielding plate 702 and the diaphragm 708 as viewed from above.

In the eccentricity measuring apparatus 700 for the patterning disk 704 shown in FIG. A. Light is shielded with the same size as (numerical aperture), and illumination light is made ring-shaped.
As a result, on the patterning disk 704, no light enters the objective lens 707 in the mirror part having no irregularities, and a dark image enters the sensor part 706.
However, since diffracted light is generated in the groove portion of the patterning disk 704, the diffracted light 709 enters the objective lens 707, and the sensor portion 706 can confirm the boundary between the mirror and the groove portion.
The patterning disc eccentricity measuring device 700 shown in FIG. 7A can be replaced with the patterning disc eccentricity measuring device described above, and the amount of eccentricity of the patterning disc can be obtained without incident illumination light obliquely. Can be measured.

The patterning disk eccentricity measuring apparatus 700 described above uses dark field illumination, but it is also possible to use pseudo dark field illumination.
In order to realize this method, the size of the light shielding plate 702 in FIG. A. It may be slightly smaller than (numerical aperture). As a result, the entire field of view becomes brighter and the surface of the observation object is illuminated, and focusing on the observation object can be easily performed.
In this case, the second illumination light source 601 for focusing described with reference to FIG. 6 is also unnecessary.

  As described above in detail, according to the present invention, even if the recording pattern of the patterning disk is miniaturized, it is possible to measure the eccentricity with high accuracy, and without using an expensive and complicated apparatus. A patterning disk eccentricity measuring apparatus and the like that can measure the eccentricity of the patterning disk with only a small change of the measurement apparatus using the image processing technique can be obtained.

It is a figure which shows an example of a structure of the eccentricity measuring apparatus of the patterning disc to which this Embodiment is applied. It is explanatory drawing in the case of discriminating the mirror part and groove part of a patterning disk using the measuring apparatus of FIG. It is a figure which shows the other example of a structure of the eccentricity measuring apparatus of the patterning disc which can apply this Embodiment. It is a figure explaining the position of X1, X2, Y1, Y2 at the time of measuring the patterning disk which has eccentricity. It is a figure which shows the other example of a structure of the eccentricity measuring apparatus of the patterning disc which can apply this Embodiment. It is a figure which shows the other example of a structure of the eccentricity measuring apparatus of the patterning disc which can apply this Embodiment. It is the figure which showed an example of the eccentricity measuring apparatus of the patterning disk which can apply this Embodiment. It is the figure which showed the eccentricity measuring apparatus of the patterning disc which measures a boundary part and calculates | requires eccentricity using the difference of the brightness of the mirror part without a groove | channel, and the groove part where a groove | channel exists by the image processing method. It is a figure explaining the diffracted light which arises when a groove part is observed when the period of the groove | channel of a patterning disk becomes fine.

Explanation of symbols

100,300,500,600,700,800 ... Eccentricity measuring apparatus for patterning disk, 101,601,701,801 ... Light source for illumination, 102,602,604,802,806 ... Lens, 103,705 ... Second 104, 201, 304, 704, 804 ... patterning disk, 105, 706, 807 ... sensor part, 106, 707, 803 ... objective lens, 107, 808 ... mirror part, 108, 809 ... groove part, 109 ... 0th order light, 110, 709, 810, 901 ... Diffracted light, 202 ... Boundary, 301 ... Rotation mechanism part, 302 ... Position detection mechanism part, 303 ... Spindle part, 305 ... Rotation control part, 306 ... Counter, 307 ... Monitor , 501 ... Discrimination mechanism part, 603, 805 ... Mirror, 702 ... Light-shielding plate, 703 ... First optical system, 708 ... Ri

Claims (9)

An illumination light source that emits illumination light;
A first optical system that collects the illumination light and irradiates the patterning disk;
A second optical system for collecting the diffracted light reflected from the patterning disk;
A sensor unit for detecting the diffracted light collected by the second optical system,
The optical axis of the first optical system and the optical axis of the second optical system have a predetermined angle. The predetermined angle is such that zero-order light is not incident on the second optical system, but diffracted light is An apparatus for measuring the eccentricity of a patterning disk, wherein the angle is incident.   2. The patterning disc eccentricity measuring apparatus according to claim 1, wherein the diffracted light is first-order diffracted light. A rotation mechanism that rotates while holding the patterning disk;
A moving mechanism that relatively moves the position of the rotating mechanism without shifting the positional relationship of the illumination light source, the first optical system, the second optical system, and the sensor;
A position detection mechanism that detects a relative position between the light source for illumination, the first optical system, the second optical system, and the sensor unit and the rotation mechanism;
A discriminating mechanism for discriminating a groove portion and a mirror portion of the patterning disc;
The patterning disk eccentricity measuring apparatus according to claim 1, further comprising:   The discriminating mechanism unit converts the diffracted light detected by the sensor unit into an electric signal, and determines the strength of the electric signal by setting a threshold value, thereby determining the groove and the mirror unit of the patterning disc. The eccentricity measuring apparatus for a patterning disk according to claim 3, wherein: A second illumination light source that emits illumination light;
A third optical system for collecting the illumination light emitted from the second illumination light source and irradiating the patterning disk;
Further comprising
2. The patterning disk eccentricity measuring apparatus according to claim 1, wherein the second-order optical system collects zero-order light reflected from the patterning disk out of the illumination light applied to the patterning disk. . An illumination light source that emits illumination light;
A light-shielding plate that selectively blocks illumination light that directly enters the patterning disk among the illumination light;
A first optical system that collects the illumination light and irradiates the patterning disk;
A second optical system that condenses the diffracted light that passes through the patterning disk and is diffracted;
A sensor unit for detecting the diffracted light collected by the second optical system;
An apparatus for measuring the eccentricity of a patterning disk, comprising:   7. The patterning disk eccentricity measuring apparatus according to claim 6, wherein the diffracted light is first-order diffracted light.   7. The patterning disc eccentricity measuring apparatus according to claim 6, wherein the illumination light applied to the patterning disc by the first optical system is applied as pseudo dark field illumination. The illumination light emitted from the illumination light source is condensed by the first optical system, and irradiated to the patterning disk.
The diffracted light reflected from the patterning disk is collected by a second optical system,
An eccentricity measuring method for a patterning disk, wherein the eccentricity amount of the patterning disk is measured by detecting the diffracted light collected by the second optical system.

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