JP2004327018A - Evaluation sample and method for evaluating positioning accuracy of recording medium test equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for quantitatively grasping the positioning accuracy when the test place of a recording medium is moved from a head to a probe in the recording medium test equipment provided with the head for reading the recorded information of the recording medium and the probe for reading the recorded pattern. <P>SOLUTION: An evaluation sample 50 on which a first data mark 51 that can be read by an optical pickup and the probe is recorded at a preset position on a recording surface is adopted. In addition, a positioning accuracy evaluating method comprising a first detecting process for detecting the first data mark 51 with the optical pickup, a moving process for turning the evaluation sample 50, a second detecting process for detecting the record pattern of the first data mark 51 with the probe, and an evaluating process for comparing differences of detection positions of the first data mark 51 between the first and second detecting processes to calculate the positioning accuracy is adopted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an evaluation sample for evaluating the positioning accuracy of a recording medium inspection device, and a positioning accuracy evaluation method using the evaluation sample.

  A scanning probe microscope (hereinafter, referred to as SPM) scans the surface of a sample with a mechanical probe and detects the interaction between the probe and the surface of the sample. -9m) It is a device to observe in the following order. As a typical example of this type of SPM, an atomic force microscope (which detects an atomic force acting between the probe and the sample surface as a change in the amount of deflection of the probe and observes the surface shape of the sample based on the detection result). Hereinafter, this is referred to as AFM). A combination of this type of AFM and an inspection device is disclosed (for example, see Patent Document 1).

  The conventional SPM generally has a scanning unit for raster-scanning a sample in the X and Y directions, a sample is placed thereon, and a probe is arranged on the surface of the sample. The scanning unit is provided on a coarse movement unit that operates in the Z direction, so that the sample surface can be brought close to the probe. For example, in the case of an AFM, the sample surface is brought close to a distance at which an atomic force acts between the sample surface and the tip of the probe by the coarse movement means, and the sample is scanned in the XY directions with respect to the probe in this state, so that the sample surface is scanned. It is possible to observe the shape and the like.

  One example of this type of conventional SPM is shown in FIG. The SPM shown in the figure has a cylindrical piezoelectric element 101 fixed and arranged so that the central axis is oriented in a vertical direction, and a sample 102 is mounted on a free end side thereof. A probe 103 is arranged above the sample 102. The cylindrical piezoelectric element 101 is fixed on a coarse movement stage 104 in the Z direction for bringing the surface of the sample 102 and the probe 103 close to each other. Above the probe 103, a probe displacement detecting means 105 to which a feedback circuit 106 is connected is arranged. The feedback circuit 106 is connected to the cylindrical piezoelectric element 101. Further, an XY scanning circuit 107 is connected to the cylindrical piezoelectric element 101.

The sample 102 can be scanned in the X and Y directions and finely moved in the Z direction by the cylindrical piezoelectric element 101. In order to enable this driving, a plurality of divided electrodes are provided on the side surface of the cylindrical piezoelectric element 101. The cylindrical piezoelectric element 101 is bent or expanded and contracted by controlling which of these electrodes a voltage is applied to. Generally, bending is used as an operation in the X and Y directions, and expansion and contraction is used as an operation in the Z direction. The distance between the sample 102 and the probe 103 is detected by the probe displacement detecting means 105. As the probe displacement detecting means 105, there is a method using an optical lever or an optical interferometer. While scanning the sample 102 in the XY directions by the XY scanning circuit 107, a drive voltage for finely moving the cylindrical piezoelectric element 101 in the Z direction is applied from the feedback circuit 106, so that the distance between the sample 102 and the probe 103 is always constant. Control. When the control signal and the XY scanning signal are input to the monitor 108, the surface state of the sample 102 can be reproduced as an image.
JP-A-8-152430 (pages 4-5, FIG. 10)

By the way, in the early days of STM and AFM, which are the pioneers of this kind of SPM, the observation targets are an atomic image of a metal surface and a molecular arrangement of a monomolecular film, and observation and research of a fine structure on a sample surface are mainly performed. It was intended for use. In such applications, a simple configuration of the SPM device was sufficient because the sample could be crushed and prepared as a small section.
However, in recent years, as the SPM is generalized / spread as a measurement device, there is an increasing demand to collate and compare the measurement result of the SPM with the measurement result of another measuring device. This tendency is particularly noticeable in the development and trial production process of industrial products.

For example, when the SPM is used for an evaluation test of an optical disk represented by a DVD-ROM, if an attempt is made to inspect the entire recording surface only with the SPM, an unrealistic measurement time is required. For this reason, first, a signal is read out from the recording surface using an optical inspection device equipped with an optical pickup to specify the position of the error location, and then the physical shape of the specified error location is focused on by SPM. Is being considered. In this case, the position information of the error location in the coordinates on the recording surface is important, but there is a possibility that the position information may be lost when the optical disc is transferred from the optical inspection device to the SPM. As a means for solving such a problem, the development of a combined measurement device (not shown) in which the optical inspection device and the SPM are combined into one device has been advanced. In this device, an optical pickup that can read optical signals and a head that measures the physical shape of a measurement location are arranged on an optical disk fixed on a rotating stage, and the position of an error location is specified by the optical pickup. In such a case, the rotation stage is rotated to move the error location to the measurement area of the probe. As a result, it is possible to consistently perform from identification of an error portion to measurement of its physical shape without the need to remove the optical disk.
In this apparatus, since the positioning accuracy when moving the error location from the reading position of the optical pickup to the inspection area of the probe is important, means for quantitatively grasping the positioning accuracy is required.

  The present invention has been made in view of the above circumstances, and in a recording medium inspection apparatus including a head for reading recording information on a recording medium and a probe for reading a recording pattern, an inspection location of the recording medium is moved from the head to the probe. The purpose is to provide a means for quantitatively grasping the positioning accuracy at the time of the operation.

The present invention employs the following means in order to solve the above problems.
That is, the evaluation sample according to claim 1 is a recording medium inspection apparatus having a head that reads out recording information of a recording medium and a probe that reads out a recording pattern that forms the recording information. This is an evaluation sample used for evaluating the positioning accuracy when moved from the position of the probe to the position of the probe, a data mark readable by the head and the probe is recorded at a preset position on a recording surface. It is characterized by having.

  According to the evaluation sample of the first aspect, after the data sample is attached to the recording medium inspection device and the data mark is detected by the head, the data mark is moved from the position of the head to the position of the probe to detect the data mark. I do. Then, the data mark was moved from the position of the head to the position of the probe by calculating a relative displacement between the position of the data mark in the coordinate system of the head and the position of the data mark in the coordinate system of the probe. In this case, the displacement can be quantitatively determined.

  The evaluation sample according to claim 2 is the evaluation sample according to claim 1, wherein the data mark is used for an evaluation test of a recording medium inspection device that inspects an optical disk as the recording medium, and the data mark is located in a radial direction of the optical disk. Alternatively, one or both of the rotation direction positions are provided.

  According to the evaluation sample described in the second aspect, the positional deviation caused when the inspection position of the optical disk is moved from the head to the position of the probe is reduced by one or both of the radial position and the rotational position of the optical disk. It can be obtained quantitatively as position information.

  According to a third aspect of the present invention, there is provided the evaluation sample according to the first or second aspect, wherein another data mark for optical microscope measurement is recorded near the data mark. .

  According to the evaluation sample described in the third aspect, when the recording medium inspection apparatus is inspected by using the evaluation sample, even if the data mark directed to the position of the probe is greatly deviated from the detection area of the probe, the optical sample is optically inspected. By detecting other data marks with a microscope, the position of the data mark can be captured.

  The positioning accuracy evaluation method for a recording medium inspection device according to claim 4, wherein the recording medium inspection device includes a head that reads out recording information of a recording medium and a probe that reads out a recording pattern that forms the recording information. A method for evaluating positioning accuracy when an inspection point is moved from the position of the head to the position of the probe, wherein the data mark of an evaluation sample in which a data mark is recorded at a preset position on a recording surface A first detecting step of detecting by the head, a moving step of moving the evaluation sample so that the data mark detected in the first detecting step enters an inspection area of the probe, and a moving step after the moving step. A second detection step of detecting the recording pattern of the data mark with the probe, and a detection position of the data mark in the second detection step By comparing the detected position of the data marks in the first detection step, and having an evaluation step of obtaining the positioning accuracy.

  According to the positioning accuracy evaluation method of the recording medium inspection apparatus according to the fourth aspect, in the evaluation step, the data mark is moved by comparing the difference between the data mark positions between the first detection step and the second detection step. It is possible to quantitatively determine the displacement at the time of the movement.

  According to a fifth aspect of the present invention, there is provided a method for evaluating the positioning accuracy of a recording medium inspection apparatus, wherein the recording medium evaluation apparatus is used for an optical disk evaluation test. In the evaluation step, the positioning accuracy of one or both of a radial direction and a rotational direction of the optical disc is evaluated by referring to the data mark.

  According to the method for evaluating the positioning accuracy of a recording medium inspection apparatus according to the fifth aspect, the positional deviation caused when the inspection location of the optical disk is moved from the position of the head to the position of the probe is determined by the radial position or rotation of the optical disk. It can be obtained quantitatively as position information of one or both of the direction positions.

  According to a sixth aspect of the present invention, in the method for evaluating a positioning accuracy of a recording medium inspection apparatus according to the fourth or fifth aspect, an optical microscope measuring method is provided near the data mark. Another data mark is recorded, and in the second detecting step, the approximate position of the data mark is obtained by confirming the position of the other data mark with an optical microscope.

  According to the method for evaluating the positioning accuracy of a recording medium inspection apparatus according to claim 6, even if the data mark directed to the position of the probe deviates greatly from the detection area of the probe, the position of the data mark can be determined using an optical microscope. Can be captured.

  The evaluation sample according to claim 1 of the present invention employs a configuration in which a data mark readable by a head and a probe is recorded at a predetermined position on a recording surface. By applying the evaluation sample to the recording medium inspection apparatus and actually measuring the position deviation of the data mark, it becomes possible to quantitatively grasp the positioning accuracy when the inspection point of the recording medium is moved from the head to the probe.

  Further, the evaluation sample according to claim 2 is used for an evaluation test of a recording medium inspection device for inspecting an optical disk, and the data mark is a position information of one or both of a radial position and a rotational position of the optical disk. Was adopted. According to this configuration, it is possible to quantitatively determine any one of the radial position and the rotational position when the inspection point of the optical disk is moved from the head to the probe. As a result, it is possible to accurately grasp in which direction and how much the positional shift has occurred.

  Further, the evaluation sample according to claim 3 employs a configuration in which another data mark for optical microscope measurement is recorded near the data mark. According to this configuration, when the data mark is moved from the head to the position of the probe, even if there is a relatively large displacement such that the position of the data mark is out of the detection area of the probe, the other data can be read. Since the position of the mark can be detected with an optical microscope, the data mark is not lost.

  According to a fourth aspect of the present invention, there is provided a method for evaluating the positioning accuracy of a recording medium inspection apparatus, comprising: a first detecting step of detecting a data mark of an evaluation sample by a head; a moving step of moving the evaluation sample; A method including a second detection step of detecting with a probe, and an evaluation step of comparing the difference between the detection positions of the data marks between the first detection step and the second detection step to determine the positioning accuracy was adopted. According to this method, it is possible to quantitatively grasp the positioning accuracy when the inspection point of the recording medium is moved from the head to the probe by actually measuring the displacement of the data mark.

  In addition, the positioning accuracy evaluation method for a recording medium inspection device according to claim 5, wherein the recording medium evaluation device performs an evaluation test on the optical disk, and in the evaluation step, any one of a radial position and a rotation direction position of the optical disk is performed. A method of evaluating one or both was adopted. According to this method, it is possible to quantitatively determine one of the radial position and the rotational position when the inspection point of the optical disk is moved from the head to the probe. As a result, it is possible to accurately grasp in which direction and how much the positional shift has occurred.

  The positioning accuracy evaluation method for a recording medium inspection device according to claim 6, wherein another data mark for optical microscope measurement is recorded near a data mark, and the other data mark is recorded in the second detection step. A method of determining the approximate position of the data mark by confirming the position of the mark with an optical microscope was adopted. According to this method, when the data mark is moved from the head to the position of the probe, even if there is a relatively large displacement such that the position of the data mark is out of the detection area of the probe, the other data can be obtained. Since the position of the mark can be detected with an optical microscope, the data mark is not lost.

  Each embodiment of the evaluation sample and the method for evaluating the positioning accuracy of the recording medium inspection device of the present invention will be described below with reference to the drawings. However, it is needless to say that the present invention is not limited to these. . The evaluation sample of the present invention is a recording medium inspection apparatus having a head for reading recording information of a recording medium and a probe for reading a recording pattern forming the recording information. This is used for evaluating the positioning accuracy when the object is moved to the position. Therefore, the recording medium inspection apparatus to be evaluated will be described first, and then the description of the evaluation sample and the positioning accuracy evaluation method will be continued.

  As shown in FIG. 1, a DVD-ROM inspection apparatus (recording medium inspection apparatus) of the present embodiment includes a stage 10 for fixing a DVD-ROM (recording medium) 1 and a DVD-ROM 1 set on the stage 10. An optical head 20 for reading out a signal, an atomic force microscope (hereinafter, referred to as an AFM) 30 which is a scanning probe microscope (SPM) for reading out a data pit shape (recording pattern) of the DVD-ROM 1, and on the stage 10. A drive unit 40 for relatively moving the detection areas of the optical head 20 and the AFM 30 with respect to the DVD-ROM 1, a control unit (not shown) for controlling the optical head 20, the AFM 30 and the drive unit 40, and an optical microscope (not shown). And is schematically configured.

  The stage 10 includes a rotary stage 11 on which the DVD-ROM 1 is directly mounted, an X stage 12 on which the rotary stage 11 is mounted, a Y stage 13 on which the X stage 12 is mounted, and a Y stage 13 Are mounted on the base 14, and motors 15, 16, 17 for driving the rotary stage 11, the X stage 12, and the Y stage 13.

The Y stage 13 is supported to be slidable in the Y direction shown in FIG. The X stage 12 is supported so as to be slidable in the X direction shown in FIG. The rotation stage 11 is supported so as to be able to rotate around the axis of the DVD-ROM 1 (around an axis parallel to the Z direction). Further, the rotation stage 11 is provided with a rotation angle sensor (not shown) for detecting the rotation angle thereof, so that the rotation angle of the rotation stage 11 with respect to the optical head 20 and the AFM 30 can be matched. It has become.
Therefore, the DVD-ROM 1 is rotated about its axis by driving the motor 15, the DVD-ROM 1 is finely moved linearly in the X direction by driving the motor 16, and the motor 17 is driven. Thus, the DVD-ROM 1 can be finely moved linearly in the Y direction.

The optical head 20 includes an optical pickup (head) 21 that reads information recorded on the DVD-ROM 1, a drive mechanism 22 that moves the optical pickup 21 in the radial direction of the DVD-ROM 1, and an optical pickup position detection sensor 23. I have.
Therefore, by moving the optical pickup 21 by the drive mechanism 22, it is possible to move the reading point along the radial direction of the DVD-ROM 1. At this time, the position signal of the optical pickup position detection sensor 23 is sequentially transmitted to the control unit, so that the position of the readout point is read out in real time. The unit performs feedback control for causing the drive mechanism 22 to perform position correction.

  The AFM 30 includes a probe 31, a cylindrical piezoelectric element 32 to which the probe 31 is attached at a lower end (free end), a Z stage 33 for roughly moving the probe 31 and the cylindrical piezoelectric element 32 in the Z direction, and a Z stage A motor 34 for driving the probe 31 and a probe displacement sensor (not shown) for detecting the displacement of the probe 31 are provided.

The probe 31 has a sharpened tip, and by scanning the surface of the DVD-ROM 1, it is possible to acquire the data pit shape formed on the recording surface of the DVD-ROM 1 with high resolution. I have. As the probe 31, for example, a nanotube probe is used.
Further, the cylindrical piezoelectric element 32 is fixedly arranged on the Z stage 33 so that the center axis thereof is oriented in the vertical direction (Z direction). The Z stage 33 is supported so as to be slidable with respect to the base 14 in the Z direction shown in FIG. 3 by the driving of the motor 34, so that the probe 31 can be moved toward and away from the recording surface. It has become. Further, the distance between the recording surface and the tip of the probe 31 can be detected by the probe displacement sensor.

The drive section 40 is composed of the motors 15, 16, 17, and 34, and by these, the positions of the optical pickup 21 and the probe 32 can be moved relative to the DVD-ROM 1. I have.
The control unit can record and analyze signals from the optical pickup 21 in addition to controlling each component of the drive unit 40. In other words, the control unit controls the rotation speed of the DVD-ROM 1, the state of the electric signal determined by the depth, length, cross-sectional shape, number, interval, etc. of the object to be detected, based on the result of the analysis using the comparative standard sample in advance. Stored as data. By comparing the standard data with the measurement data measured by the optical pickup 21, it is possible to identify the cause of the error pit.

  According to the DVD-ROM inspection apparatus of the present embodiment having the above-described configuration, it is possible to quickly identify the error position of the inspection target DVD-ROM 1 and observe the shape of the data pit that caused the error. It is possible. This will be described with reference to FIGS.

  First, by fixing the DVD-ROM 1 to be inspected on the rotating stage 11, the disk reading is started, and the process proceeds to step S1 in FIG. In this step S1, the optical pickup 21 is on the back surface of the recording surface of the DVD-ROM 1 (this surface has no protective film, the reflective film coating is exposed and the data pit shape is exposed). The laser beam is radiated and the reflected light is received, and a physical change in the reflected light is sequentially detected as a change in an electric signal. At this time, the position signal from the optical pickup position detection sensor 23 is transmitted to the control unit, thereby acquiring the address information of the current measurement location. The address information includes a track number, a radius r from the rotation center on the disk shown in FIG. 3, and an angle θ from a reference angle of 0 degree on the disk.

  In subsequent step S2 of FIG. 2, the control unit analyzes the electric signal read in step S1, and determines that an error location (error data pit, flaw, etc.) has occurred when it is determined to be out of a predetermined standard. The address is stored as found (step S3). If not, the process returns to step S1 and repeats the signal test until the completion of the reading in step S4 is satisfied. In this way, by performing the steps S1 to S4 as a scanning step of reading the recording information and obtaining the position information of the error location in the DVD-ROM 1, the address information of the error location on the recording surface of the DVD-ROM 1 is specified. be able to. The time required for this step is substantially the same as the reading time of the disk in actual use, and can be performed in a very short time.

In a succeeding step S5, an address conversion for transmitting the address information of the error location stored in the step S3 to the AFM 30 is performed. That is, the track number of each error location is converted into position coordinates defined by the radius r and the angle θ. The address information of each error location converted in this way is transmitted to the AFM 30 in step S6.
In the following step S7, when there are a plurality of error locations, an object to be measured by the AFM 30 is selected from these. This selection work may be made to be selected by an operator, or may be made to be prioritized by the control unit according to the degree of error.

  In the following step S8, the selected error location is led into the inspection area of the AFM 30, and the data pit shape is measured. At this time, as shown in FIGS. 4A and 4B, the probe 31 of the AFM 30 is separated from the optical pickup 21 by a predetermined angle (for example, 90 degrees) when viewed in a plan view. The DVD-ROM 1 is rotated by the motor 15 by the predetermined angle from the position. Thus, the rotation direction coordinates of the probe 31 can be made to match the rotation direction coordinates of the optical pickup 21, and the address information converted in step S5 can be used as it is. Subsequently, the probe 31 is moved in the radial direction of the DVD-ROM 1 so that the positions in the radial direction match. Thus, the position of the probe 31 is positioned just above the position defined by the radius r and the angle θ.

  In this state, the probe 31 measures the shape of the data pit and compares it with the standard data to identify the cause.

  As described above, after the recording pattern measuring step of reading the recording pattern of the error portion with the probe 31 based on the position information specified in the scanning step, the analyzing step of analyzing the recording pattern by the control unit is performed in error. By repeatedly performing each location, the cause of each error is identified.

Next, a first embodiment of an evaluation sample for evaluating the positioning accuracy of the DVD-ROM inspection device described above and a positioning accuracy evaluation method using the sample will be described below with reference to FIG.
As shown in the figure, the evaluation sample 50 of the present embodiment is a DVD-ROM disk having the same dimensions as the DVD-ROM 1, and the optical pickup 21 and the probe 31 are set at predetermined positions on the recording surface. A first data mark (data mark) 51 which can be read by is recorded.

  The first data mark 51 has a number of continuous pit rows (pseudo error pits) having a length within the scanning range of the probe 31 in one track. In the example of FIG. ), And a similar pit row is formed one track at a time at the same angular position from the center of the disk toward the outer periphery, so that the mark is formed as one line that can be detected by the AFM 30. According to the first data mark 51, it is possible to evaluate the positioning accuracy in the radial direction in the DVD-ROM inspection device, and details thereof will be described later.

  Further, on the recording surface of the evaluation sample 50, a second data mark (other data mark) 52 for optical microscope measurement is recorded near the first data mark 51. The second data mark 52 has a larger number of pits than the first data mark 51 (in the example of FIG. 1, a pit row of 1000 consecutive pits) is adjacent to a track at an arbitrary position in the radial direction formed by the first data mark 51. Is formed at the same angular position by several tracks to form a quadrangular region having a fixed area that can be detected by an optical microscope.

  Then, a plurality of the second data marks 52 are formed at equal intervals along the first data mark 51 (three positions are formed in the case of FIG. 3), so that an arbitrary position in the radial direction can be optical microscope. When observing with the, the closest second data mark 52 can be confirmed. Then, by confirming these second data marks 52 with the optical microscope, the approximate position of the adjacent first data mark 51 can be obtained. The details will be described later.

  Further, at the innermost position on the recording surface of the evaluation sample 50, a ring-shaped third data mark 53 formed by forming a circular pit array that goes around the disk over several tracks is recorded. According to the third data mark 53, the innermost circumferential position of the recording surface can be accurately confirmed. The details will be described later.

A positioning accuracy evaluation method using the evaluation sample 50 having the configuration described above will be described below.
First, the evaluation sample 50 is placed and fixed on the rotating stage 11 of the DVD-ROM inspection device to be evaluated. Then, the optical pickup 21 irradiates the recording surface of the evaluation sample 50 with the laser light and receives the reflected light, and sequentially detects a physical change of the reflected light as a change of the electric signal. When the first data mark 51 is scanned, the data pit is detected, and at the same time, a position signal from the optical pickup position detection sensor 23 is transmitted to the control unit. By performing the first detection step of detecting the first data mark 51 of the evaluation sample 50 in this manner, the rotation direction position of the first data mark 51 on the recording surface (address information indicating an angle from the reference angle of 0 degree). ) Is determined.

Subsequently, a moving step of rotating the evaluation sample 50 so that the first data mark 51 detected in the first detecting step enters the inspection area of the probe 31 is performed. At this time, as shown in FIGS. 4A and 4B, the probe 31 of the AFM 30 has a predetermined angle (for example, 90 degrees) with respect to the optical pickup 21 when viewed in a plan view. The evaluation sample 50 is rotated by the motor 15 by the predetermined angle from the position of the optical pickup 21.
At this time, if the rotation direction coordinates of the optical head 20 match the rotation direction coordinates of the AFM 30, and if the rotation / stop accuracy of the motor 15 is sufficient, the rotation is stopped within the detection area of the probe 31 (preferably the probe 31). (The position immediately below the first data mark 51).

  Then, a second detection step of detecting the data pit shape (recording pattern) of the first data mark 51 after the movement step with the probe 31 is performed. At this time, if the probe 31 cannot find the first data mark 51 due to considerable deviation in the positioning accuracy, the position of the second data mark 52 is visually confirmed using the optical microscope. Thus, even if the first data mark 51 deviates from the detection area of the probe 31, it is possible to specify the approximate position thereof.

Subsequently, an evaluation step for determining the positioning accuracy is performed by comparing the detection position of the first data mark 51 in the second detection step with the detection position of the first data mark in the first detection step. That is, if the rotational direction position of the first data mark 51 measured in the first detection step is, for example, θ1 degrees with respect to the reference angle, and if measured in the second detection step, becomes θ2 degrees. , And these angle differences = θ1-θ2 are obtained as rotational positioning errors in the DVD-ROM inspection device. Therefore, by performing feedback for correcting the rotation amount of the motor 15 based on the positioning error, the device can be calibrated with high accuracy.
Similarly, by measuring the third data mark 53 in the first detection step and the second detection step, it is possible to confirm the positioning accuracy of the reference position in the disk radial direction.

  By performing the first detection step, the movement step, the second detection step, and the evaluation step using the evaluation sample 50 of the present embodiment described above, the inspection location of the DVD-ROM is moved from the optical pickup 21 to the probe 31. It is possible to quantitatively grasp the positioning accuracy at the time of the operation. Further, it is possible to calibrate the apparatus based on the positioning accuracy.

Further, according to the evaluation sample 50 of the present embodiment, by recording the second data mark 52 for optical microscope measurement, the position of the first data mark 51 is relatively large such that the position of the first data mark 51 is out of the detection area of the probe 31. Even if the displacement occurs, the position of the second data mark 52 can be detected by the optical microscope, so that the first data mark is not lost. This makes it possible to reliably measure the positioning accuracy.
The number of the first data marks 51 is not limited to one, and a plurality of first data marks 51 may be formed. In this case, the positioning accuracy can be obtained with higher accuracy.

Next, a second embodiment of an evaluation sample for evaluating the positioning accuracy of the DVD-ROM inspection device and a positioning accuracy evaluation method using the sample will be described below with reference to FIG.
As shown in the figure, the evaluation sample 60 of the present embodiment is a DVD-ROM disc having the same outer diameter as the DVD-ROM 1, and the optical pickup 21 and the optical pickup 21 are set at predetermined positions on the recording surface. A fourth data mark 61 and a fifth data mark 62 readable by the probe 31 and a sixth data mark 63 observable by the optical microscope are recorded.

  The fourth data mark 61 is a ring-shaped mark formed on the innermost peripheral position of the recording surface of the evaluation sample 60 over a plurality of tracks in a circulating pit array that goes around the disk. By checking the fourth data mark 61, the innermost position on the recording surface can be checked accurately.

The fifth data mark 62 has a length of several consecutive pits (pseudo error pits, which are within the scanning range of the probe 31) in one track. In the example of FIG. Is formed as a single line that can be detected by the AFM 30 by forming a similar pit row one track at a time at the same angle from the center of the disk toward the outer circumference. The fifth data mark 62 includes a one-line mark formed to have a predetermined length in the radial direction from the next track of the last track on which the fourth data mark 61 is recorded, and the one-line mark. Is formed so as to have the same dimension as the predetermined length in the radial direction from the position next to the last track on which is recorded and shifted by a predetermined angle (in the case of FIG. And the predetermined length in the radial direction from a position next to the last track on which the single line mark is recorded and shifted by a predetermined angle (in the case of FIG. And another one-line mark formed to have the same dimensions.
According to the three fifth data marks 62, it is possible to evaluate both the positioning accuracy in the radial direction and the positioning accuracy in the rotation direction in the DVD-ROM inspection device, and details thereof will be described later. I do.

The sixth data mark 63 is adjacent to the outermost peripheral portion of each fifth data mark 62 and has a larger number of pit rows than those fifth data marks 62 (in the example of FIG. Is formed at the same angular position by several tracks, thereby forming a quadrangular region having a constant area that can be detected by an optical microscope.
These sixth data marks 63 form flag-like marks when viewed integrally with the fifth data marks 62 adjacent thereto. Then, according to the sixth data marks 63, the approximate positions of the adjacent fifth data marks 62 can be obtained by confirming them with an optical microscope. The details will be described later.

A positioning accuracy evaluation method using the evaluation sample 60 having the configuration described above will be described below.
First, the evaluation sample 60 is placed and fixed on the rotating stage 11 of the DVD-ROM inspection device to be evaluated. Then, the optical pickup 21 irradiates the recording surface of the evaluation sample 60 with the laser light and receives the reflected light, and sequentially detects a physical change of the reflected light as a change of the electric signal. When the fifth data mark 62 is scanned, a position signal from the optical pickup position detection sensor 23 is transmitted to the control unit at the same time as detecting the data pit. By performing the first detection step of detecting all the fifth data marks 62 of the evaluation sample 60 in this manner, the rotational position of the fifth data mark 62 on the recording surface (indicating the angle from the reference angle of 0 °). Address information) and the radial position (address information indicating the distance from the fourth data mark 61) are determined.

Subsequently, a moving step of rotating the evaluation sample 60 such that the fifth data mark 62 detected in the first detection step enters the inspection area of the probe 31 is performed. At this time, as shown in FIGS. 4A and 4B, the probe 31 of the AFM 30 has a predetermined angle (for example, 90 degrees) with respect to the optical pickup 21 when viewed in a plan view. The evaluation sample 60 is rotated by the motor 15 by the predetermined angle from the position of the optical pickup 21.
At this time, if the rotation direction coordinates of the optical head 20 match the rotation direction coordinates of the AFM 30, and if the rotation / stop accuracy of the motor 15 is sufficient, the rotation is stopped within the detection area of the probe 31 (preferably the probe 31). (The position just below the fifth data mark 62).

  Then, a second detecting step of detecting the data pit shape (recording pattern) of the fifth data mark 62 after the moving step with the probe 31 is performed. At this time, if the probe 31 cannot find the fifth data mark 62 due to considerable deviation in the positioning accuracy, the position of the sixth data mark 63 is visually confirmed using the optical microscope. Thus, even if the fifth data mark 62 deviates from the detection area of the probe 31, it is possible to specify the approximate position thereof.

Subsequently, an evaluation step of comparing the detection position of the fifth data mark 62 in the second detection step with the detection position of the fifth data mark 62 in the first detection step to determine the rotational and radial positioning accuracy is performed. Done.
That is, regarding the positioning accuracy in the rotational direction, the rotational direction position of the fifth data mark 62 when measured in the first detection step is, for example, θ1 degrees with respect to the reference angle, and when measured in the second detection step, this is When the angle becomes θ2 degrees, these angle differences = θ1−θ2 are obtained as positioning errors in the rotation direction in the DVD-ROM inspection device.
Regarding the positioning accuracy in the radial direction, the innermost peripheral position of the fifth data mark 62 measured at the first detection step is located at a distance of r1 from the fourth data mark 61, and is measured at the second detection step. If the distance becomes r2 at the time of performing, the dimensional difference = r1-r2 is obtained as a positioning error in the radial direction in the DVD-ROM inspection apparatus.

  By performing the first detection step, the movement step, the second detection step, and the evaluation step using the evaluation sample 60 of the present embodiment described above, the inspection location of the DVD-ROM is moved from the optical pickup 21 to the probe 31. It is possible to quantitatively grasp the positioning accuracy in the rotation direction and the radial direction at the time of the operation. Further, it is possible to calibrate the apparatus based on the positioning accuracy.

Further, according to the evaluation sample 60 of the present embodiment, by recording the sixth data mark 63 for optical microscope measurement, the position of the fifth data mark 62 is relatively large so as to be out of the detection area of the probe 31. Even if the position shift occurs, the position of the sixth data mark 63 can be detected by the optical microscope, so that the fifth data mark 62 is not lost. This makes it possible to reliably measure the positioning accuracy.
Note that the flag-shaped mark including the fifth data mark 62 and the sixth data mark 63 is not limited to three places, and may be formed at two places or four or more places.

(Example)
The evaluation sample 50 described in the first embodiment and the evaluation sample 60 described in the second embodiment are manufactured, and the DVD-ROM inspection device (recording medium inspection) actually described in the first embodiment is actually manufactured. The positioning accuracy of the device was evaluated, and the positioning was adjusted based on the result of the positioning accuracy evaluation.
Thereafter, the positioning accuracy of the DVD-ROM inspection device was evaluated again using each of the evaluation samples 50 and 60.
FIGS. 7A to 7D show the results when the evaluation sample 50 as the radial direction adjustment sample was used. FIGS. 7A to 7D target a corner which is a connection between the first data mark 51 and the second data mark whose position has been confirmed by the optical head 20. The moving image is moved from the scanning range of the optical head 20 to the scanning range of the AFM 30 by the driving of the driving unit 40, and the image when the scanning range is further scanned by the AFM 30 is shown. As shown in these figures, all of the corners fall within the scanning range of the AFM 30, and the evaluation sample 50 is extremely effective for positioning adjustment and positioning accuracy evaluation of the DVD-ROM inspection device. Was actually confirmed.

  On the other hand, FIGS. 8A to 8D show the results when the evaluation sample 60, which is a sample for adjusting the angle, is used. FIGS. 8A to 8D show a case where the corner of the sixth data mark 63 whose position has been confirmed by the optical head 20 is targeted, and the corner of the sixth data mark 63 is The moving image is moved from the scanning range to the scanning range of the AFM 30, and an image when the scanning range is further scanned by the AFM 30 is shown. As shown in these figures, all of the corners fall within the scanning range of the AFM 30, and this evaluation sample 60 is also extremely effective for adjusting the positioning accuracy and evaluating the positioning accuracy of the DVD-ROM inspection apparatus. It was actually confirmed.

FIG. 1 is a perspective view illustrating a main part of a DVD-ROM inspection device according to a first embodiment of a recording medium inspection device of the present invention. It is a flowchart which shows the control flow of the same DVD-ROM inspection apparatus. FIG. 4 is an explanatory diagram for describing coordinates on a DVD-ROM attached to the DVD-ROM inspection device. 3A and 3B are diagrams illustrating an arrangement of an optical pickup and a probe in the DVD-ROM inspection device, wherein FIG. 3A is a side view and FIG. It is a front view showing a 1st embodiment of an evaluation sample of the present invention. It is a front view showing a 2nd embodiment of an evaluation sample of the present invention. (A)-(d) is a figure which shows the result of actually producing the evaluation sample of the said 1st Embodiment, and applying it to the positioning precision adjustment and positioning precision evaluation of a recording medium inspection apparatus, and an AFM evaluation sample. Shows an image scanned by. (A)-(d) is a figure which shows the result of actually manufacturing the evaluation sample of the said 2nd Embodiment, and applying it to the positioning precision adjustment and positioning precision evaluation of a recording medium inspection apparatus, and an evaluation sample by AFM. Shows an image scanned by. It is explanatory drawing which shows an example of the conventional scanning probe microscope (SPM).

Explanation of reference numerals

1 ... DVD-ROM (recording medium)
21 ... Optical pickup (head)
31 ... probe 50, 60 ... evaluation sample 51 ... first data mark (data mark)
52... Second data mark (other data mark)
53 ... third data mark (data mark)
61 ... fourth data mark (data mark)
62: Fifth data mark (data mark)
63 ... sixth data mark (other data mark)

Claims (6)

When a test point of the recording medium is moved from the position of the head to the position of the probe in a recording medium inspection device having a head for reading recording information of a recording medium and a probe for reading a recording pattern forming the recording information. This is an evaluation sample used to evaluate the positioning accuracy of
An evaluation sample, wherein a data mark readable by the head and the probe is recorded at a predetermined position on a recording surface. In the evaluation sample according to claim 1,
Used for an evaluation test of a recording medium inspection device that inspects an optical disk as the recording medium,
An evaluation sample, wherein the data mark has position information on one or both of a radial position and a rotational position of the optical disc. In the evaluation sample according to claim 1 or claim 2,
An evaluation sample, wherein another data mark for optical microscope measurement is recorded near the data mark. When a test point of the recording medium is moved from the position of the head to the position of the probe in a recording medium inspection device having a head for reading recording information of a recording medium and a probe for reading a recording pattern forming the recording information. Is a method of evaluating the positioning accuracy of
A first detection step of detecting, with the head, the data mark of the evaluation sample in which the data mark is recorded at a preset position on a recording surface;
A moving step of moving the evaluation sample so that the data mark detected in the first detecting step enters an inspection area of the probe;
A second detection step of detecting the recording pattern of the data mark after the movement step with the probe;
An evaluation step of determining the positioning accuracy by comparing a detection position of the data mark in the second detection step with a detection position of the data mark in the first detection step. Positioning accuracy evaluation method. The positioning accuracy evaluation method for a recording medium inspection device according to claim 4,
The recording medium evaluation device is used for an evaluation test of an optical disc,
In the evaluation step, a positioning accuracy of a recording medium inspection apparatus is evaluated by referencing the data mark to evaluate a positioning accuracy in one or both of a radial direction and a rotating direction of the optical disc. The positioning accuracy evaluation method for a recording medium inspection device according to claim 4 or 5,
In the vicinity of the data mark, another data mark for optical microscope measurement is recorded,
In the second detecting step, the approximate position of the data mark is obtained by confirming the position of the other data mark with an optical microscope, and the positioning accuracy evaluation method for a recording medium inspection device is characterized in that

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