JP2009085766A - Apparatus for inspecting outer circumference of disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for inspecting the outer circumferences of disks and capable of maintaining the focal position of a light-receiving device in focus even if a wafer is suddenly displaced in a horizontal direction and in a vertical direction, preventing the focal position of the light-receiving device from deviating, and maintaining the state of an observation point matched with the center of a field of view. <P>SOLUTION: The apparatus 1 for inspecting the outer circumferences of disks includes a displacement amount detection device 3 for detecting the amounts of displacement &Delta;X and &Delta;Y in perpendicular directions of a radial direction of a disk W and a disk surface Sw; a mirror part 4 provided with both a first mirror for reflecting scattering light L at the surface Ws and a second mirror 42 for reflecting its reflected light in parallel with the optical axis of the scattering light L in the opposite direction; and an actuator 5 for moving the mirror part 4 in the direction of the optical axis and a direction perpendicular to it. In the case that the scattering light L is scattered by the surface Ws in the (downward, positive) direction of an angle &theta;, the actuator 5 moves the mirror part 4 in the direction of the optical axis of the scattering light L at the surface Ws and a direction perpendicular to it each by (&Delta;Xcos&theta;-&Delta;Ysin&theta;)/2 and (&Delta;Xsin&theta;+&Delta;Ycos&theta;)/2. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a disk body outer periphery inspection device, and in particular, inspects the surface of the outer periphery of a disk body by irradiating light to the outer periphery of a disk body such as a wafer and detecting the scattered light and reflected light. It is related with the disc body outer periphery inspection apparatus which performs.

  In the case of a disk body material, it may be required that there are no scratches or irregularities on the outer peripheral portion as well as the disk surface. In particular, in the field of wafers and hard disks, it is strongly required that the surface of a substrate such as a wafer be free of irregularities and scratches including defects, cracks, crystal defects, etc. Although various developments have been made (see, for example, Patent Document 1), it is also required that the chamfered portion of the outer peripheral portion of a wafer or the like is not damaged.

Therefore, light is irradiated to the chamfered part of the outer periphery of the wafer, etc., and the light scattered on the surface or reflected light is received by a light receiving device such as a camera or a CCD (Charge Coupled Device) to detect scratches and the like. Various disk outer periphery inspection apparatuses have been developed (see, for example, Patent Documents 2 to 4).
JP 2000-193434 A JP-A-11-351850 JP 2007-24528 A JP 2007-47010 A

  By the way, in the conventional disc body outer periphery inspection apparatus 100, as shown in FIG. 13, for example, the wafer W is placed on the rotary table so that the center Ow of the wafer W, which is a disc body, coincides with the rotation center Ot of the rotary table T. The light receiving device 102 is placed on the side of the wafer W so that the wafer W is peeled off. Then, the focus position of the light receiving device 102 is set so that the chamfered portion of the outer peripheral surface of the wafer W is in focus, and the observation point is set at the center of the visual field of the light receiving device 102.

  In this state, the rotary table T is rotated around the rotation center Ot to rotate the wafer W, and the chamfered portion of the outer peripheral portion of the rotating wafer W is irradiated with light from the light irradiation device 101, so that the outer peripheral portion of the wafer W is irradiated. The scattered light and the reflected light on the surface of the chamfered portion are received by the light receiving device 102 and the surface of the chamfered portion on the outer peripheral portion of the wafer W is photographed. In the following description, for the sake of convenience, the radial direction of the disc W, that is, the wafer W in the above example (the direction indicated by the arrow X in the figure) is the horizontal direction X, and the disc surface of the disc body, ie, the substrate of the wafer W in the above example. A direction perpendicular to the surface Sw (a direction indicated by an arrow Y in the figure) is referred to as a vertical direction Y.

  At that time, when the holding accuracy of the wafer W is low and the position of the center Ow of the wafer W and the position of the rotation center Ot of the turntable T are not exactly aligned, or when the wafer W itself is eccentric, FIG. As shown in FIG. 2, the chamfered portion on the outer peripheral portion of the wafer W is displaced in the horizontal direction X by a displacement amount ΔX corresponding to a positional deviation or an eccentricity deviation every time it rotates. Further, if the wafer W is wavy or deformed, it is displaced by a displacement amount ΔY corresponding to the waviness or warpage in the vertical direction Y every time it rotates.

  Therefore, in this state, the focus position set in advance in the light receiving device 102 is shifted, or the observation point is deviated from the center of the visual field of the light receiving device 102. In order to prevent such a situation from occurring, in the conventional disc outer periphery inspection apparatus 100, for example, the chamfered portion of the outer peripheral portion of the wafer W is matched with the displacement amounts ΔX and ΔY in the horizontal direction X and the vertical direction Y. Thus, the light receiving device 102 and the rotary table T are displaced in the horizontal direction X and the vertical direction Y by the displacement amounts ΔX and ΔY.

  However, when the surface of the chamfered portion of the outer peripheral portion of the wafer W is inspected at high speed, the chamfered portion of the outer peripheral portion of the wafer W rotating at high speed is rapidly displaced in the horizontal direction X or the vertical direction Y, so to speak, the wafer W It will be in the state which vibrates the edge part of violently. Then, it is necessary to quickly and accurately displace the light receiving device 102 and the rotary table T in accordance with the rapid displacement of the wafer W, but an actuator for displacing the heavy light receiving device 102 and the like rapidly and accurately. Are usually large and often expensive. In addition, since the light receiving device 102 and the turntable T are vibrated vigorously, a failure of the light receiving device 102 and the turntable T is caused.

  Further, at least the displacement amount ΔX in the horizontal direction X of the chamfered portion of the outer peripheral portion of the wafer W has conventionally been dealt with by using a light receiving device 102 having a deep focal depth. Since the resolution of 102 is generally low, resolution must be sacrificed when attempting to cope with the displacement in the horizontal direction X of the chamfered portion of the outer peripheral portion of the wafer W with the depth of focus.

  Further, the amount of displacement ΔX in the horizontal direction X of the chamfered portion of the outer peripheral portion of the wafer W can be dealt with by providing the light receiving device 102 with an autofocus function. The device is generally expensive, which increases the overall cost of the device.

  The present invention has been made to solve such a problem. Even when the rotating body is rapidly displaced in the horizontal direction or the vertical direction during inspection, the focus point of the light receiving device is not shifted and the observation point is set at the center of the visual field. It is an object of the present invention to provide a disc body outer periphery inspection device that can maintain a combined state and can be photographed with high resolution. It is another object of the present invention to provide a disk body outer periphery inspection device that can realize the above object at a low cost.

In order to solve the above problem, the disk body outer periphery inspection device according to claim 1,
A disk body outer periphery inspection device that inspects the surface of the outer peripheral portion of the disk body by irradiating light on the outer peripheral surface of the disk body and detecting light scattered or reflected on the surface by a light receiving device. In
A displacement amount detection device for detecting a displacement amount in a radial direction of the disk body on a surface of an outer peripheral portion of the disk body and a displacement amount in a direction orthogonal to the disk surface of the disk body;
A first mirror that reflects light scattered or reflected by the surface of the outer periphery of the disc body, and light reflected by the first mirror is scattered or reflected by the surface of the outer periphery of the disc body; A mirror unit comprising a second mirror that is parallel to the optical axis of the reflected light and reflects in the opposite direction;
An actuator that moves the mirror part in the direction of the optical axis of the light scattered or reflected by the surface of the outer peripheral part of the disc body and the direction orthogonal thereto,
The amount of displacement in the radial direction of the disk body detected by the displacement amount detection device is ΔX, and the amount of displacement in the direction perpendicular to the disk surface of the disk body is ΔY. When the light scattered or reflected in a direction having an angle θ in a direction perpendicular to the disk surface of the disk body with respect to the radial direction of the body is reflected by the first mirror of the mirror unit, the actuator is , And (ΔX × cos θ−ΔY × sin θ) / 2 and (ΔX respectively) in the direction of the optical axis of the light scattered or reflected by the surface of the outer peripheral portion of the disc body and the direction orthogonal thereto. A disc body outer periphery inspection apparatus characterized by being moved by × sinθ + ΔY × cosθ) / 2.
However, θ is positive in the downward direction with respect to the radial direction of the disc body.

  According to a second aspect of the present invention, in the disk body outer periphery inspection device according to the first aspect, the reflection surface of the second mirror of the mirror portion is 90 ° with respect to the reflection surface of the first mirror. It is provided so that it may incline.

  According to a third aspect of the present invention, in the disk body outer periphery inspection device according to the second aspect, the reflection surface of the first mirror of the mirror part is scattered on the surface of the outer peripheral part of the disk body. Alternatively, it is arranged to be inclined by 45 ° with respect to the optical axis of the reflected light.

  According to a fourth aspect of the present invention, in the disk body outer periphery inspection device according to any one of the first to third aspects, the displacement amount detection device inspects the surface of the outer peripheral portion of the disk body. A displacement amount in the radial direction of the disk body and a displacement amount in a direction perpendicular to the disk surface of the disk body are detected at a position upstream of a predetermined angle in the rotation direction of the disk body from the position. It is characterized by that.

The invention according to claim 5 is the disk body outer periphery inspection device according to any one of claims 1 to 4,
The actuator includes a first drive mechanism that moves the mirror portion in the direction of the optical axis of light scattered or reflected on the surface of the outer peripheral portion of the disc body, and a second drive that moves the mirror portion in a direction orthogonal thereto. With a mechanism,
The first driving mechanism and the second driving mechanism are driven independently.

  According to the disk body outer periphery inspection device according to any one of claims 1 to 5, the displacement amount detection device is orthogonal to the radial displacement (horizontal direction) of the disk member and the disk surface of the disk member. The amount of displacement in the direction (vertical direction) is detected, and the detected amount of displacement in the radial direction (horizontal direction) of the disc body is ΔX, the direction orthogonal to the disc surface of the disc body (vertical direction) ΔY is the amount of displacement to the disk, and the angle θ in the vertical direction with respect to the horizontal direction on the surface of the outer peripheral portion of the disk body (where θ is positive with respect to the radial direction of the disk body). In the case where light scattered or reflected in the direction of reflection is reflected by the first mirror of the mirror part, the mirror part is orthogonal to the direction of the optical axis of the scattered light or reflected light on the surface of the outer peripheral part of the disc body and Are moved by (ΔX × cos θ−ΔY × sin θ) / 2 and (ΔX × sin θ + ΔY × cos θ) / 2, respectively.

  If comprised in this way, it will become possible to always maintain the optical path length from the surface of the outer peripheral part of a disc body to a light-receiving device, and a focus position in a light-receiving device will shift from a preset focus position. Therefore, it is possible to always maintain a state in which the focus position is met. At the same time, the light reflected by the second mirror of the mirror section can be always incident on the center of the visual field of the light receiving device, and the observation point can be maintained in alignment with the visual field center of the light receiving device. Become.

  In addition, since the mirror part is a lightweight member composed of the first mirror, the second mirror, etc., even if the outer peripheral part of the disk body is rapidly displaced in the horizontal direction or the vertical direction during inspection, the mirror part is It can be moved easily and quickly in the horizontal direction and the vertical direction, and it can be moved without causing a failure, so that the above-described function can be exhibited accurately. Furthermore, since an inexpensive actuator that can accurately move the lightweight mirror portion can be used, an apparatus that can exhibit the above functions can be realized at low cost.

  Embodiments of a disk body outer periphery inspection device according to the present invention will be described below with reference to the drawings.

  In the following embodiments, the disk body is a wafer, and the case of inspecting the surface of the chamfered portion of the outer periphery of the wafer with the disk body outer periphery inspection apparatus will be described. However, the disk body outer periphery inspection apparatus of the present invention As described above, the present invention can be applied to the inspection of the outer peripheral portion of a disk plate such as a hard disk as well as the wafer, and the inspection target is not limited to the wafer. Further, as shown in FIG. 11 and the like which will be described later, in the disk body outer periphery inspection apparatus, the mirror unit 4 is positioned at a position having an arbitrary angle θ with respect to the radial direction of the disk body (wafer W), that is, the horizontal direction X. The light L scattered and reflected in the direction of the angle θ can be reflected by the first mirror 41 of the mirror unit 4, but first, hereinafter, when the angle θ is 0 °, that is, the light A case will be described in which scattered light or reflected light is detected on the surface Ws of the outer peripheral surface of the disc body (wafer W) whose axis is in the horizontal direction X.

(overall structure)
FIG. 1 is a diagram illustrating an overall configuration of a disk body outer periphery inspection device according to the present embodiment. The disc body outer periphery inspection device 1 includes a light irradiation device 2, a displacement amount detection device 3, a mirror unit 4, an actuator 5, and a light receiving device 6. In FIG. 1 and the following drawings, the ratio of the size, length, thickness, etc. of each member or wafer W does not necessarily reflect reality.

  The wafer W, which is a disk body in the present embodiment, is placed on the turntable T, and rotates around the rotation center Ot of the turntable T as the turntable T rotates. In the present embodiment, a lens system for condensing the light L scattered or reflected by the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W is omitted, but is appropriately provided.

  In the following, for simplicity, the light L scattered or reflected by the surface Ws of the chamfered portion of the outer periphery of the wafer W may be expressed as scattered light L. This is not intended to exclude the light reflected by the surface Ws of the chamfered portion, but also includes the case of reflected light.

(Detailed configuration)
The light irradiation device 2 is arranged at a position where visible light can be irradiated to the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W. In the present embodiment, two light irradiation devices 2 are provided above and below the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W, and the light irradiation device 2 is an outer peripheral portion of the wafer W that is an inspection object. The light having a sufficiently large beam diameter is irradiated so that the entire surface Ws can be irradiated with light.

  In the present embodiment, light is irradiated from the light irradiation device 2 to the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W, and the scattered light L is guided to the light receiving device 6 described later to be detected. In addition to this, although not shown, for example, the coaxial light is irradiated from the coaxial light source to the chamfered surface Ws of the outer peripheral portion of the wafer W through a lens system, a half mirror, etc., and the reflected light is irradiated. It is also possible to configure to guide to the light receiving device 6.

  Further, in the present embodiment, as shown in FIG. 1 and the like, a case will be described in which inspection is performed on a wafer W having a surface Ws having a structure in which upper and lower corner portions of the chamfered portion of the outer peripheral portion are beveled. The present invention is not limited to this, and the present invention is similarly applied to, for example, a wafer W formed so that the surface Ws of the chamfered portion of the outer peripheral portion is smoothly curved and wafers of other shapes.

  The displacement amount detection device 3 calculates the displacement amount ΔX of the wafer W in the radial direction of the wafer W, that is, the horizontal direction X, and the displacement amount ΔY of the wafer W in the direction orthogonal to the substrate surface Sw of the wafer W, that is, the vertical direction Y. Each is to be detected.

  Note that the displacement amounts ΔX and ΔY in the horizontal direction X and the vertical direction Y of the wafer W mean the displacement amounts ΔX and ΔY in the horizontal direction X and the vertical direction Y of the chamfered portion of the outer peripheral portion of the wafer W. . In the present invention, when referring to the radial direction of the disk body (wafer W) or the direction orthogonal to the disk surface (substrate surface Sw) of the disk body (wafer W), an ideal disk without undulation or warping. This refers to the radial direction of the body (wafer W) or the direction orthogonal to the disk surface (substrate surface Sw) of the disk body (wafer W). In the present embodiment, the rotation table T shown in FIG. A direction perpendicular to the rotation axis At or a direction parallel to the rotation axis.

  In the present embodiment, the displacement amount detection device 3 detects the displacement amount ΔX of the wafer W in the horizontal direction X and the first displacement amount detection device 31 that detects the displacement amount ΔY of the wafer W in the vertical direction Y. The two displacement amount detection device 32 is configured as a separate body.

  As shown in FIG. 2, the first and second displacement amount detection devices 31 and 32 are configured so that the rotation center of the turntable T is rotated when the rotation of the turntable T (not shown) causes the wafer W to rotate in the direction of the arrow. The displacement amounts ΔX and ΔY are detected at the end position of the wafer W on the line connecting Ot and the center position of the mirror section 4 to be described later, that is, the position upstream of the inspection position A by a predetermined angle θdetect in the rotation direction. Yes.

  Note that FIG. 2 shows the case where the predetermined angle θdetect is 90 °, that is, the case where the displacement amounts ΔX and ΔY are detected at a position 90 ° upstream from the inspection position A in the rotation direction. The predetermined angle θdetect is not limited to 90 °, and if the position does not hinder the inspection, the displacement amounts ΔX and ΔY may be detected from the inspection position A at an arbitrary angle in the rotation direction. it can.

  In the present embodiment, the first displacement amount detection device 31 is configured by arranging a light emitting device 31 a and a light receiving device 31 b above and below the end portion of the position of the wafer W. From the light emitting device 31a, a parallel light beam L1 that is wide in the radial direction of the wafer W so as to straddle the inside and outside of the end portion and narrow in the tangential direction of the end portion of the wafer W is directed toward the light receiving device 31b. Thus, the light is irradiated in the vertical direction Y.

  If comprised in this way, as shown in FIG. 3, some parallel rays L1 irradiated from the light-emitting device 31a will be interrupted | blocked by the wafer W. FIG. The displacement amount ΔXa of the parallel beam L1 measured in the horizontal direction X in the length Xa corresponds to the displacement amount ΔX of the wafer W in the horizontal direction X. That is, the displacement amount ΔX in the horizontal direction X of the wafer W is based on the displacement amount ΔXa of the length Xa in the horizontal direction X of the parallel light beam L1 detected by the light receiving device 31b of the first displacement amount detection device 31. It can be obtained as -ΔXa obtained by multiplying it by -1.

  As shown in FIG. 2, the second displacement amount detection device 32 includes a light emitting device 32a that irradiates a parallel light beam L2 that passes through the vicinity of the end of the position of the wafer W, and a light receiving device 32b that receives the light. Yes. From the light emitting device 32a, as shown in FIG. 4, a parallel light beam L2 that is wide in the vertical direction Y and narrow in the radial direction of the wafer W, that is, in the direction orthogonal to the paper surface, is directed horizontally toward the light receiving device 32b. X is irradiated.

  With this configuration, a part of the parallel light beam L2 irradiated from the light emitting device 32a is blocked by the wafer W. The displacement amount ΔYa of the length Ya from the upper end in the vertical direction Y of the parallel light beam L2 measured by the light receiving device 32b corresponds to the displacement amount ΔY of the wafer W in the vertical direction Y. That is, the displacement amount ΔY in the vertical direction Y of the wafer W is changed to the displacement amount ΔYa of the length Ya from the upper end in the vertical direction Y of the parallel light beam L2 detected by the light receiving device 32b of the second displacement amount detection device 32. Based on this, it can be obtained as -ΔYa obtained by multiplying it by -1.

  As will be described later, the displacement amounts ΔX and ΔY obtained in this way are the displacement amounts ΔX and ΔY at positions upstream of the actual inspection position A by a predetermined angle θdetect in the rotation direction, and the wafer W Further, it is utilized at the time when it is rotated by a predetermined angle θdetect.

  In FIG. 1, the second displacement amount detection device 32 is not shown. Further, the displacement amount detection device 3 is not limited to the present embodiment as long as it can detect displacement amounts ΔX and ΔY in the horizontal direction X and the vertical direction Y of the wafer W. It is also possible to use a sensor or the like that irradiates the wafer W with light or the like and measures the displacements ΔX and ΔY by a trigonometric method, a confocal method, a phase difference method, or the like.

  As shown in FIG. 1, the mirror unit 4 includes a first mirror 41 and a second mirror 42. In the present embodiment, the first mirror 41 is disposed such that the reflection surface 41a is inclined by 45 ° with respect to the optical axis of the scattered light L on the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W. The two mirrors 42 are fixed to the first mirror 41 via the connecting piece 43 so that the reflection surface 42 a is inclined by 90 ° with respect to the reflection surface 41 a of the first mirror 41.

  The mirror part 4 reflects the scattered light L on the surface Ws of the chamfered part of the outer peripheral part of the wafer W by the first mirror 41 by arranging the first mirror 41 and the second mirror 42 as described above. The light reflected by the first mirror 41 is reflected by the second mirror 42 in the opposite direction parallel to the optical axis of the scattered light L.

  In this embodiment, the actuator 5 includes a horizontal drive unit 51 and a vertical drive unit 52. The horizontal drive unit 51 and the vertical drive unit 52 have first and second drives each having a drive motor (not shown). It has a mechanism. The horizontal driving unit 51 is fixed to a support base or the like so that the longitudinal direction is directed to the horizontal direction. The vertical drive unit 52 can be translated in the horizontal direction X while maintaining a posture standing with respect to the horizontal drive unit 51, and is moved in parallel by driving the first drive mechanism of the horizontal drive unit 51. It has become.

  Further, the mirror unit 4 is supported by the vertical drive unit 52 so as to be movable in the vertical direction, and the mirror unit 4 is moved in the horizontal direction X according to the parallel movement of the vertical drive unit 52. The mirror unit 4 is moved in the vertical direction Y with respect to the vertical drive unit 52 by the drive of the second drive mechanism of the vertical drive unit 52.

  The mirror unit 4 is driven in the horizontal direction X by independently driving the first drive mechanism provided in the horizontal drive unit 51 of the actuator 5 and the second drive mechanism provided in the vertical drive unit 52. And movement in the vertical direction Y are controlled independently of each other.

  In the present embodiment, the light reflected by the second mirror 42 of the mirror unit 4 is incident on the light receiving device 6 after the optical axis is further bent by the third mirror 8. The reason why the optical axis of the light reflected by the second mirror 42 is further bent by the third mirror 8 is to prevent the light receiving device 6 from blocking the optical path of the scattered light L, and the light receiving device 6 scatters. In the case where the optical path of the light L is not blocked, the third mirror 8 is not necessarily provided.

  In FIG. 1, the light receiving device 6 is disposed above the optical axis of the scattered light L on the surface Ws of the chamfered portion of the outer periphery of the wafer W, and the light reflected by the second mirror 42 of the mirror unit 4 is the first. Although the case where the light is reflected in the vertical direction Y by the three mirrors 8 and incident on the light receiving device 6 has been described, the arrangement of the light receiving device 6 is not limited to this, and the arrangement position of the light receiving device 6 is appropriately set and the third mirror is set. 8 can be configured to reflect light in the direction of the light receiving device 6.

  As the light receiving device 6, a light receiving element such as a camera or a CCD can be used as in the conventional light receiving device. It is also possible to dispose light guiding means such as an image fiber, a lens system, or the like between the light receiving device 6 and the third mirror 8 or the second mirror 42.

  In addition, the light receiving device 6 has an outer periphery of the wafer W in a state where the wafer W is placed on the turntable T so that the center thereof is aligned with the position of the rotation center Ot of the turntable T (hereinafter referred to as a reference state). When the scattered light L from the surface Ws of the chamfered portion enters through the mirror unit 4 or the like, the focus position is adjusted so that the surface Ws is in focus, and the observation point is aligned with the center of the visual field of the light receiving device 6 To be adjusted.

  FIG. 5 is a block diagram showing a control configuration of the disk body outer periphery inspection device 1 according to the present embodiment. In this embodiment, the disk body outer periphery inspection device 1 is configured by a computer (not shown) having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface and the like connected to a bus. The control device 7 is provided.

  The control device 7 includes the two light irradiation devices 2 described above, the displacement amount detection device 3 having the first displacement amount detection device 31 and the second displacement amount detection device 32, the horizontal drive unit 51, and the vertical drive unit 52. The actuator 5 for moving the provided mirror unit 4 in the horizontal direction X and the vertical direction Y, the light receiving device 6 and the like are connected. The control device 7 controls these members to surface the chamfered portion of the outer peripheral portion of the wafer W. Ws is photographed to detect scratches on the surface Ws.

  In addition, the control device 7 is connected to a rotary table T, a control device that controls the rotary operation of the rotary table T, and the like, so that information about the rotational speed of the rotary table T, that is, the rotational angle per unit time can be acquired. It has become.

(Function)
Next, an operation of the disk body outer periphery inspection device 1 according to the present embodiment will be described.

  In the disc body outer periphery inspection device 1 according to the present embodiment, the control device 7 allows the wafer W in a reference state in which the wafer W having a predetermined diameter is accurately placed on the rotary table T before starting the inspection. When the scattered light L from the surface Ws of the chamfered portion of the outer peripheral portion enters the light receiving device 6 via the mirror portion 4 or the like, the focus position is adjusted so that the observation point is aligned with the visual field center of the light receiving device 6. The position of the mirror unit 4 in the horizontal direction X or the vertical direction Y is adjusted in advance by driving the first drive mechanism or the second drive mechanism of the horizontal drive unit 51 or the vertical drive unit 52, and the focus position of the light receiving device 6 is adjusted. Is done.

  Further, the control device 7 acquires in advance information on the rotational speed of the rotary table T from the rotary table T and stores it in its own storage means such as a RAM. Then, when the control device 7 acquires the rotation speed of the turntable T, based on the rotation speed, a predetermined distance from the position where the turntable T or the wafer W detects the displacement amounts ΔX and ΔY to the inspection position A (see FIG. 2). The time Δt required to rotate the angle θdetect is calculated and stored in the storage means.

  At the time of inspection, the control device 7 first drives the first displacement amount detection device 31 and the second displacement amount detection device 32 of the displacement amount detection device 3 to perform a predetermined rotation direction from the inspection position A with the above capacity. The displacement amounts ΔX and ΔY of the wafer W in the horizontal direction X and the vertical direction Y are detected at a position upstream of the angle θdetect, and the information is obtained from the first displacement amount detection device 31 and the second displacement amount detection device 32. To do. And the control apparatus 7 memorize | stores the information of displacement amount (DELTA) X, (DELTA) Y in a memory | storage means.

  Acquisition and storage of information on the displacement amounts ΔX and ΔY from the first displacement amount detection device 31 and the second displacement amount detection device 32 of the displacement amount detection device 3 acquire information for at least one round of the outer peripheral portion of the wafer W. It continues until it finishes. It should be noted that the information on the displacement amounts ΔXa and ΔYa described above is obtained from the first displacement amount detection device 31 and the second displacement amount detection device 32, and the displacement amounts ΔX and ΔY are calculated from the information by the control device 7, respectively. You may comprise as follows.

  Further, the control device 7 irradiates visible light onto the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W from the two light irradiation devices 2. Irradiation with visible light is continued until the inspection of one wafer W is completed.

  As the information of the displacement amounts ΔX and ΔY in the horizontal direction X and the vertical direction Y of the chamfered portion of the outer peripheral portion of the wafer W currently at the inspection position A, the control device 7 uses the information from the inspection position A before the time Δt as the information. The displacement amounts ΔX and ΔY of the chamfered portion of the outer peripheral portion of the wafer W at the current inspection position A detected at the position upstream of the predetermined angle θdetect in the rotation direction and stored in the storage means are read out.

  Then, the control device 7 drives the first drive mechanism of the horizontal drive unit 51 of the actuator 5 based on the read displacement amounts ΔX and ΔY, thereby moving the mirror unit 4 in the horizontal direction X by half of the displacement amount ΔX, that is, ΔX. The second drive mechanism of the vertical drive unit 52 of the actuator 5 is driven to move the mirror unit 4 in the vertical direction Y by a half of the displacement amount ΔY, that is, ΔY / 2.

  Thus, the optical path from the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W to the light receiving device 6 is moved by moving the position in the horizontal direction X and the position in the vertical direction Y of the mirror unit 4 by ΔX / 2 and ΔY / 2. The length is the same as the optical path length in the reference state. That is, the optical path length from the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W to the light receiving device 6 is always kept constant. Therefore, it is possible to prevent the focus position in the light receiving device 6 that has been adjusted and set in advance from being shifted and maintain the focus position. In addition, it is possible to maintain a state where the observation point of the light reflected by the second mirror 42 of the mirror unit 4 matches the center of the visual field of the light receiving device 6. Hereinafter, the above two points will be described.

For example, as shown in FIG. 6, the chamfered portion of the outer peripheral portion of the wafer W is not displaced in the vertical direction Y (ΔY = 0) at the inspection position A, and is displaced by a displacement amount ΔX in the horizontal direction X. ^Assume that it is in the position of ^* . In this case, as described above, the mirror unit 4 is translated in the horizontal direction X by ΔX / 2 in the horizontal direction X by the actuator 5 and moved to the position of the mirror unit 4 ^{* in} the drawing.

In this state, the optical path length of the scattered light L ^* from the surface Ws ^* chamfer first to mirror 41 ^* mirror 4 ^* of after the movement of the outer peripheral portion of the displaced wafer W ^* is the wafer W in the reference state From the optical path length of the scattered light L from the surface Ws of the chamfered portion of the outer peripheral portion to the first mirror 41 of the mirror 4, ΔX−ΔX / 2 = ΔX / 2 (1)
Only shortened.

However, since the mirror part is merely translated in the horizontal direction X, the optical path length from the first mirror 41 ^* to the second mirror 42 ^* in the mirror part 4 ^* after the movement is the first mirror in the mirror part 4 in the reference state. from 41 unchanged from the optical path length to the second mirror 42, also the optical path length from the mirror portion 4 ^* of the second mirror 42 ^* to the light receiving device 6 after movement, the second mirror 42 of the mirror 4 in the reference state From the optical path length to the light receiving device 6 by ΔX / 2.

Therefore, the total optical path length from the surface Ws ^* of the chamfered portion of the outer peripheral portion of the displaced wafer W ^* expressed by the sum of the optical path lengths described above to the light receiving device 6 is the chamfer of the outer peripheral portion of the wafer W in the reference state. It becomes equal to the total optical path length from the surface Ws of the part to the light receiving device 6, and the optical path length is kept constant.

As can be seen from FIG. 6, when the mirror unit 4 is translated in the horizontal direction X, the angle of the mirror unit 4 with respect to the scattered light L of the first mirror 41 and the second mirror 42 is maintained. progressive displaced wafer W ^* of the periphery scattered light from the surface Ws ^* of chamfer portion L ^* in X, the mirror portion 4 ^* each mirror, is reflected at the same reflection angle scattered light L in the reference state .

Therefore, light directed to the light receiving device 6 is reflected by the mirror portion 4 ^* of the second mirror 42 ^* after the movement are the same as light directed to the light receiving device 6 is reflected by the second mirror 42 of the mirror section 4 in the reference state Follow the path. Therefore, if the observation point of the light reflected by the second mirror 42 in the reference state is in a state where it matches the center of the field of view of the light receiving device 6, it is reflected by the second mirror 42 ^* of the mirror part 4 ^* after movement. The state where the light observation point matches the center of the visual field of the light receiving device 6 is also maintained.

Note that FIG. 6 illustrates the case where the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W is displaced to the left side in the drawing, but when the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W is displaced to the right side of the drawing, That is, the same explanation when the displacement amount ΔX is a negative value can be easily understood by reversing the wafer W in the reference state and the displaced wafer W ^* in FIG.

On the other hand, for example, as shown in FIG. 7, the chamfered portion of the outer peripheral portion of the wafer W is not displaced in the horizontal direction X (ΔX = 0) at the inspection position A, but is displaced by the displacement amount ΔY in the vertical direction Y. And at the position of W ^# . In this case, as described above, the mirror section 4 is moved by ΔY / 2 in the vertical direction Y by the actuator 5 and moved to the position of the mirror section 4 ^{# in} the drawing.

In this state, the optical path length of the scattered light L ^# from the surface Ws ^# of the chamfered portion of the outer peripheral portion of the displaced wafer W ^# to the first mirror 41 ^# of the mirror unit 4 ^# after movement is hatched in the drawing. As can be seen from the fact that the triangles α and β are congruent isosceles right triangles, the scattered light L from the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W to the first mirror 41 of the mirror 4 in the reference state. Is longer than the optical path length by ΔY / 2.

Further, as shown in FIG. 8, the light that is reflected at a right angle by the first mirror 41 ^♯ of the mirror portion 4 ^♯ after the movement is reflected further right angle by the second mirror 42 ^♯, the optical path and the reference at that time The triangle γ indicated by hatching in the figure formed by the reflecting surface 42a of the second mirror 42 in the state is also a right-angled isosceles triangle congruent with the triangles α and β and having a length of ΔY / 2. It becomes.

The light reflected by the first mirror 41 in the reference state is reflected by the second mirror 42 at the position of one vertex P of the triangle γ. Therefore, from the point P in the figure, the light reflected by the second mirror 42 ^# of the mirror unit 4 ^# after movement and directed to the light receiving device 6 is reflected by the second mirror 42 of the mirror unit 4 in the reference state. The light traveling toward the light receiving device 6 follows the same path.

Therefore, if the observation point of the light reflected by the second mirror 42 in the reference state is in a state where it matches the center of the visual field of the light receiving device 6, it is reflected by the second mirror 42 ^# of the mirror unit 4 ^# after movement. The state where the light observation point matches the center of the visual field of the light receiving device 6 is also maintained.

Further, the optical path length from the first mirror 41 ^♯ the mirror portion 4 ^♯ after the movement to the second mirror 42 ^♯, only ΔY than the optical path length from the first mirror 41 in the mirror unit 4 in the reference state to the second mirror 42 Shorter. Further, the optical path length from the second mirror 42 ^♯ of the mirror portion 4 ^♯ after the movement to the light receiving device 6, as long as [Delta] Y / 2 from the optical path length from the second mirror 42 of the mirror 4 to the light receiving device 6 in the reference state Become.

Therefore, the total optical path length of the scattered light L ^♯ from the surface Ws ^♯ chamfered portion of the outer peripheral portion of the displaced wafer W ^♯ to the light receiving device 6, the optical path length of the scattered light L in the reference state, the surface Ws ^♯ From the first mirror 41 ^# to the first mirror 41 ^# of the mirror 4 ^# after the movement is increased by ΔY / 2, and between the first mirror 41 ^# and the second mirror 42 ^# after the movement is shortened by ΔY. longer by [Delta] Y / 2 in the second mirror 42 ^♯ of the mirror portion 4 ^♯ to the light receiving device 6. As a result, the optical path length is equal to the total optical path length from the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W to the light receiving device 6 in the reference state. In this case, the optical path length is kept constant.

  As described above, when the displacement amounts in the horizontal direction X and the vertical direction Y of the chamfered portion of the outer peripheral portion of the wafer W at the inspection position A are ΔX and ΔY, the position of the mirror unit 4 in the horizontal direction X By moving the position in the vertical direction Y by ΔX / 2 and ΔY / 2, it becomes possible to keep the optical path length from the surface Ws of the chamfered portion of the outer periphery of the wafer W to the light receiving device 6 constant. 6 can maintain a state in which the focus position is matched.

  At the same time, the mirror unit 4 is reflected by the second mirror 42 of the mirror unit 4 by moving the position of the mirror unit 4 in the horizontal direction X and the position of the vertical direction Y by ΔX / 2 and ΔY / 2 as described above. It is possible to maintain a state in which the light observation point matches the center of the visual field of the light receiving device 6.

  While the inspection is being performed, the wafer W rotates with the rotation of the rotary table T, and the displacement amounts ΔX and ΔY in the horizontal direction X and the vertical direction Y of the chamfered portion of the outer peripheral portion of the wafer W at the inspection position A are obtained. Constantly changing.

  The control device 7 always reads out the displacement amounts ΔX and ΔY corresponding to the chamfered portion of the outer peripheral portion of the wafer W at the inspection position A from the storage means, and performs the first drive mechanism and the vertical drive of the horizontal drive unit 51 of the actuator 5. By driving the second driving mechanism of the driving unit 52 and moving the mirror unit 4 in the horizontal direction X and the vertical direction Y by ΔX / 2 and ΔY / 2, the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W is removed. The optical path length to the light receiving device 6 is always kept constant. In addition, the observation point of the light reflected by the second mirror 42 of the mirror unit 4 is always maintained in a state where it matches the visual field center of the light receiving device 6.

(effect)
As described above, according to the disk body outer periphery inspection device 1 according to the present embodiment, the displacement amount detection device 3 is orthogonal to the displacement amount ΔX in the radial direction of the disk body such as the wafer W, that is, the horizontal direction X. The amount of displacement ΔY in the direction, that is, the vertical direction Y is detected. And when inspecting the surface part of the outer peripheral part of the disk body which detected those displacement amount (DELTA) X, (DELTA) Y, the actuator 5 was driven and it was scattered or reflected by the surface of the outer peripheral part of a disk body The mirror unit 4 including the first mirror 41 and the second mirror 42 for reflecting the light L in the direction opposite to the traveling direction is moved by ΔX / 2 in the horizontal direction X and ΔY / 2 in the vertical direction Y.

  With this configuration, the optical path length from the surface of the outer peripheral portion of the disc body to the light receiving device 6 can be always kept constant, and the light receiving device 6 can always maintain a focused position. It becomes possible. At the same time, it is possible to keep the observation point of the light reflected by the second mirror 42 of the mirror unit 4 always aligned with the visual field center of the light receiving device 6.

  Moreover, since the mirror part 4 which reflects the light L scattered or reflected from the surface of the outer peripheral part of a disc body is a member comprised by the 1st mirror 41, the 2nd mirror 42, etc., it is lightweight and compact. Can be configured. Therefore, even when the outer periphery of the disc body is rapidly displaced in the horizontal direction X or the vertical direction Y during inspection, the mirror unit 4 can be easily and quickly moved in the horizontal direction X or the vertical direction Y. The above functions can be demonstrated accurately.

  Furthermore, according to the disk body outer periphery inspection apparatus 1 according to the present embodiment, the mirror unit 4 is moved in the horizontal direction X or the vertical direction Y as described above, so that the focus position is always maintained in the light receiving device 6. In addition, the observation point of the light incident on the light receiving device 6 can always be kept in the state where it matches the center of the visual field of the light receiving device 6.

  Therefore, it is not necessary to use a light receiving device having a high-speed autofocus function as in the conventional device, and it is possible to prevent an increase in the cost of the disk body outer periphery inspection device. In addition, it is not necessary to deal with the displacement amounts ΔX and ΔY in the horizontal direction X and the vertical direction Y of the outer peripheral portion of the disc body using a device having a deep focal depth as in the conventional light receiving device, so the focal depth is shallow. However, it is possible to use a light receiving device with high resolution. Therefore, it is possible to photograph the outer peripheral portion of the disc body with high resolution.

  In addition, since the mirror unit 4 can be configured to be light and compact as described above, the actuator 5 that moves the mirror unit 4 can move the light receiving device 6 and the rotary table T, which are large in weight, quickly and accurately as in the related art. It is not necessary to use a large and expensive actuator, and it is possible to use an inexpensive actuator that can accurately move the lightweight mirror portion 4. Therefore, according to the disk body outer periphery inspection apparatus according to the present embodiment, it is possible to realize an apparatus capable of exhibiting the above functions at low cost by using an inexpensive actuator.

  In FIG. 2 and the like, in the first displacement amount detection device 31, the light emitting device 31a and the light receiving device 31b are arranged vertically, and in the second displacement amount detection device 32, the light emitting device 32a and the light receiving device 32b are arranged. Although the case where it arrange | positions to the downstream and the upstream of the rotation direction of the wafer W was shown, it is not limited to this, The displacement amount (DELTA) X and (DELTA) Y to the horizontal direction X and the vertical direction Y of the wafer W can each be detected correctly. If there is, it can be arranged at an arbitrary position.

  By the way, in the disk body outer periphery inspection apparatus 1 of the above embodiment, the mirror unit 4 is arranged in the radial direction of the disk body (wafer W), that is, in the horizontal direction X, and the outer periphery of the wafer W (disk body) is arranged. The mirror unit 4 is moved by ΔX / 2 in the direction of the optical axis of the light L scattered or reflected by the surface Ws, that is, in the horizontal direction X, and the mirror unit in the direction orthogonal to the optical axis of the light L, that is, in the vertical direction Y. The case where 4 is moved by ΔY / 2 has been described.

  However, the mirror unit 4 is moved without displacing the light receiving device 6 or the rotary table T, and the focus position in the light receiving device 6 is maintained, and the observation point of light incident on the light receiving device 6 is the light receiving device. The feature of the present invention that maintains the state of matching the visual field center of 6 is not exhibited only in the above embodiment, and various modifications are possible. Hereinafter, some modifications will be shown to expand the scope of application of the present invention.

  The above-described features of the present invention can be achieved in the same manner in the modified examples 10 and 20 of the disk body outer periphery inspection device shown in FIGS. 9 and 10, for example. In addition, in the disk body outer periphery inspection apparatus 10 and 20, the same code | symbol is attached | subjected and demonstrated about the member which has the same function as the disk body outer periphery inspection apparatus 1 of the said embodiment. 9 and 10, the illustration of the actuator that moves the mirror unit 4 is omitted.

  9, after the optical axis of the light L scattered or reflected by the surface Ws of the outer peripheral portion of the wafer W (disk body) is bent in the vertical direction Y by the fourth mirror 11. Reflected in the horizontal direction X by the first mirror 41 of the mirror unit 4, reflected in the vertical direction Y by the second mirror 42, and further reflected in the horizontal direction X by the third mirror 8 and made incident on the light receiving device 6. It is configured.

  Also in the disc body outer periphery inspection device 10, the mirror unit 4 is moved by ΔX / 2 and ΔY / 2 to maintain the focused position in the light receiving device 6, and observation of light incident on the light receiving device 6 is observed. It is possible to maintain a state where the point matches the center of the visual field of the light receiving device 6. However, at that time, the direction in which the mirror unit 4 is moved is the horizontal direction X in the embodiment described above while the direction in which the mirror unit 4 is moved by ΔX / 2 is the vertical direction Y in the disk body outer periphery inspection device 10. The direction of movement by ΔY / 2 is the vertical direction Y in the above-described embodiment, whereas in the disc body outer periphery inspection apparatus 10, the horizontal direction X is used.

  Further, in the disk body outer periphery inspection apparatus 20 in FIG. 10, a prism 21 is further provided between the outer periphery of the wafer W (disk body) and the fourth mirror 11 in the disk body outer periphery inspection apparatus 10 in FIG. 9. The optical axis of the light L scattered or reflected by the surface Ws of the outer peripheral portion of the wafer W (disk body) is refracted in an arbitrary direction.

  Also in this disc body outer periphery inspection device 20, by moving the mirror unit 4 by ΔX / 2 and ΔY / 2, the focused position in the light receiving device 6 is maintained, and the light incident on the light receiving device 6 is observed. It is possible to maintain a state where the point matches the center of the visual field of the light receiving device 6. However, at this time, the direction in which the mirror unit 4 is moved by ΔX / 2 or the direction in which the mirror unit 4 is moved by ΔY / 2 is no longer the horizontal direction X or the vertical direction Y.

  When these disk body outer periphery inspection apparatuses 10 and 20 and the disk body outer periphery inspection apparatus 1 of the above-described embodiment are considered together, the prism is also reflected by the fourth mirror 11 (see FIG. 9). In either case, the mirror unit 4 is refracted by the lens 21 (see FIG. 10) or is directly incident on the mirror unit 4 (see FIG. 1 etc.). The light L scattered or reflected by the surface Ws of the light is moved by ΔX / 2 in the direction of the optical axis of the light L immediately before entering the mirror unit 4, and is moved by ΔY / 2 in the direction perpendicular to the optical axis. If the second mirror 42 of the unit 4 is configured to reflect the light L in the opposite direction parallel to the optical axis of the light L incident on the first mirror 41, it can be seen that the above-described features of the present invention are exhibited. .

  Here, considering in detail the case of the disk body outer periphery inspection apparatus 1, 10, 20 of the above-described embodiment or modification, the mirror unit 4 is oriented in the direction of the optical axis of the light L immediately before entering the mirror unit 4. In the case of the movement, the wafer W (disk body) is moved by a half ΔX / 2 of the radial displacement amount ΔX. In any of the above cases, the detected light L is the light L scattered or reflected in the horizontal direction X on the surface Ws of the outer peripheral portion of the wafer W (disk body). The distance ΔX in the radial direction of the body) is the distance between the surface Ws of the outer peripheral portion of the wafer W (disk body) and the mirror section 4 after all, though the fourth mirror 11 and the prism 21 are used. Is equal to the amount of displacement.

  That is, in the present invention, the mirror unit 4 is displaced in the direction of the optical axis of the light L immediately before entering the mirror unit 4 by the distance between the surface Ws of the outer peripheral portion of the wafer W (disk body) and the mirror unit 4. The movement is made by a half ΔX / 2 of the amount ΔX. Further, when the mirror unit 4 is moved in a direction orthogonal to the direction of the optical axis of the light L immediately before entering the mirror unit 4, the direction orthogonal to the optical axis of the detected light L, that is, the above-mentioned In this case, the substrate surface Sw (disk surface) of the wafer W (disk body) that is perpendicular to the light L scattered or reflected in the horizontal direction X on the outer surface Ws of the wafer W (disk body). The amount of displacement ΔY in the direction orthogonal to is used as a reference, and is moved by ΔY / 2, which is half of that amount.

  When viewed in this way, the present invention further shows that, as shown in FIG. 11, the mirror unit 4 has an arbitrary angle θ (however, the horizontal direction X with respect to the radial direction of the wafer W (disc body)). θ can also be expanded when it is arranged at a position having the radial direction of the wafer W (disk body), that is, the downward direction is positive with respect to the horizontal direction X as a reference.

  That is, in the disk body outer periphery inspection apparatus 30 configured to enter the mirror portion 4 with the light L scattered or reflected in the angle θ direction with respect to the radial direction of the wafer W (disk body), the mirror The portion 4 is moved in the direction of the optical axis of the light L immediately before entering the mirror portion 4 by a half of the displacement amount of the distance between the surface Ws of the outer peripheral portion of the wafer W (disk body) and the mirror portion 4; In the direction orthogonal to the direction, it is configured to move by half the amount of displacement in the direction orthogonal to the optical axis of the detected light L.

In this case, the wafer W (disk body) is displaced by ΔX in the radial direction and is orthogonal to the substrate surface Sw (disk surface) of the wafer W (disk body), as in the above-described embodiment. 12, the displacement amount ΔX ^* of the distance between the surface Ws of the outer peripheral portion of the wafer W (disk body) and the mirror portion 4 is expressed by the displacement amounts ΔX and ΔY and the above-described amounts as shown in FIG. Using the angle θ,
ΔX ^* = ΔX × cos θ−ΔY × sin θ (2)
The amount of displacement ΔY ^{* in the} direction perpendicular to it can be calculated as follows:
ΔY ^* = ΔX × sin θ + ΔY × cos θ (3)
Can be calculated.

Therefore, the mirror unit 4 is disposed at a position having an arbitrary angle θ with respect to the radial direction of the wafer W (disk body) as shown in FIG. 11, that is, the horizontal direction X, and is scattered or reflected in the angle θ direction. In the disc body outer periphery inspection device 30 configured to reflect the light L by the first mirror 41 of the mirror unit 4, the mirror unit 4 is moved by ΔX in the direction of the optical axis of the light L immediately before entering the mirror unit 4. It can be seen that it is only necessary to move half of ^* , that is, (ΔX × cos θ−ΔY × sin θ) / 2, and to move by half of ΔY ^* , that is, (ΔX × sin θ + ΔY × cos θ) / 2 in the direction orthogonal thereto.

  When the present invention is expanded and grasped in this way, each disk body outer periphery inspection device in the above-described embodiment or its modification is the same as the disk body outer periphery inspection device 30 in FIG. Corresponds to the case. The angle θ is normally set in a range of + 90 ° to −90 °, with the downward direction being positive with respect to the radial direction of the wafer W (disk body).

  In summary, in the disk body outer periphery inspection apparatus according to the present invention, the wafer W (disk body) is scattered or reflected by the surface Ws of the outer periphery, and the radial direction of the wafer W (disk body), that is, the horizontal direction. When the light L scattered or reflected in the direction of an angle θ with respect to X (where θ is a positive direction with respect to the radial direction of the wafer W (disk body)) is incident on the mirror unit 4, The mirror unit 4 is moved by (ΔX × cos θ−ΔY × sin θ) / 2 in the direction of the optical axis of the light L immediately before incidence, and is moved by (ΔX × sin θ + ΔY × cos θ) / 2 in a direction perpendicular to the mirror L, The second mirror 42 of the mirror unit 4 is configured to reflect the light L in the opposite direction parallel to the optical axis of the light L incident on the first mirror 41.

  And if comprised in this way, even after moving the mirror part 4, the total optical path length from the surface Ws of the outer peripheral part of the wafer W (disk body) to the light-receiving device 6 will be adjusted before an inspection start. In the set reference state, it becomes equal to the total optical path length from the surface Ws of the chamfered portion of the outer peripheral portion of the wafer W to the light receiving device 6, and the optical path length is maintained constant. Further, the light incident on the light receiving device 6 can be made to follow the same path as the light incident on the light receiving device 6 in the reference state, and the observation point of the light matches the visual field center of the light receiving device 6 in the reference state. If it is adjusted to the state, the observation point of the light incident on the light receiving device 6 is also in the state that matches the center of the visual field of the light receiving device 6 even after the mirror unit 4 is moved, and the above-described features of the present invention are exhibited.

  Further, as described above, the present invention is not limited to the light L scattered or reflected in the horizontal direction X on the surface Ws of the outer peripheral portion of the wafer W (disk body), but also in the radial direction of the wafer W (disk body). Is also applied to the light L scattered or reflected in the direction of the angle θ set arbitrarily. Therefore, for example, when the disc body is the wafer W, not only the end surface of the chamfered portion of the outer peripheral portion of the wafer W but also the so-called bevel surface inspection in which the upper and lower corner portions of the chamfered portion are chamfered in a bevel shape. Can also be performed. That is, according to the disc body outer periphery inspection device of the present invention, it becomes possible to inspect the entire outer periphery of the disc body.

  In the above-described embodiment and the like, as shown in FIG. 2, the amount of displacement in the radial direction of the disk body such as the wafer W at a position upstream of the inspection position A of the rotary table T by the predetermined angle θdetect in the rotational direction. A displacement amount ΔY in a direction perpendicular to ΔX and the disk surface (substrate surface Sw) of the disk body is detected, and after the detection, the displacement amounts ΔX and ΔY are stored from the storage means after a time Δt required to rotate by a predetermined angle θdetect. The case where reading is used to move the mirror unit 4 has been described. However, the detection of the displacement amounts ΔX and ΔY and the timing of using them are not limited to this. For example, the displacement amounts ΔX and ΔY are obtained in advance by associating the displacement amounts ΔX and ΔY with the angle θdetect for the entire outer periphery of the disc body. In addition, it is also possible to configure so as to read out from the storage means when inspecting the outer peripheral portion of the disc body at another timing.

It is a figure which shows the whole structure of the disc body outer periphery inspection apparatus which concerns on this embodiment. It is a schematic plan view explaining the detection position of the displacement amount in this embodiment. It is a figure explaining how to detect the amount of displacement in the horizontal direction by the first displacement amount detector. It is a figure explaining how to detect the amount of displacement in the perpendicular direction by the second amount of displacement detector. It is a block diagram which shows the control structure of the disc body outer periphery inspection apparatus which concerns on this embodiment. It is a figure explaining an effect | action at the time of moving a mirror part to a horizontal direction only by the half amount of displacement to the horizontal direction of a wafer. It is a figure explaining an effect | action at the time of moving a mirror part to the perpendicular direction only by the half amount of displacement to the perpendicular direction of a wafer. It is a figure explaining an effect | action at the time of moving a mirror part to the perpendicular direction only by the half amount of displacement to the perpendicular direction of a wafer. It is a figure which shows the whole structure of the modification of the disc body outer periphery inspection apparatus of FIG. It is a figure which shows the whole structure of the modification of the disc body outer periphery inspection apparatus of FIG. It is a figure which shows the whole structure of the modification of the disc body outer periphery inspection apparatus of FIG. It is a figure explaining the displacement amount of the distance between the surface of the outer peripheral part of the disc body in the modification of FIG. 11, and a mirror part, and the displacement amount of the direction orthogonal to it. It is a figure which shows the whole structure of the conventional disc body outer periphery inspection apparatus. It is a figure explaining the state which displaces a light-receiving device by the amount of displacement to the horizontal direction of a wafer, or a perpendicular direction with the disc body outer periphery inspection apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Disc body outer periphery inspection apparatus 3 Displacement amount detection apparatus 4 Mirror part 41 1st mirror 41a Reflective surface 42 of 1st mirror 2nd mirror 42a Reflective surface 5 of 2nd mirror Actuator 6 Light receiving apparatus A Inspection position L Light (scattered light) )
Sw disk surface (substrate surface)
W disk (wafer)
Ws Surface X Radial direction of disk (horizontal direction)
ΔX Horizontal displacement Y Direction perpendicular to the disk surface of the disk (vertical direction)
ΔY Vertical displacement amount θ Angle of scattered or reflected light with respect to the radial direction of the disk body θdetect Predetermined angle

Claims (5)

A disk body outer periphery inspection device that inspects the surface of the outer peripheral portion of the disk body by irradiating light on the outer peripheral surface of the disk body and detecting light scattered or reflected on the surface by a light receiving device. In
A displacement amount detection device for detecting a displacement amount in a radial direction of the disk body on a surface of an outer peripheral portion of the disk body and a displacement amount in a direction orthogonal to the disk surface of the disk body;
A first mirror that reflects light scattered or reflected by the surface of the outer periphery of the disc body, and light reflected by the first mirror is scattered or reflected by the surface of the outer periphery of the disc body; A mirror unit comprising a second mirror that is parallel to the optical axis of the reflected light and reflects in the opposite direction;
An actuator that moves the mirror part in the direction of the optical axis of the light scattered or reflected by the surface of the outer peripheral part of the disc body and the direction orthogonal thereto,
The amount of displacement in the radial direction of the disk body detected by the displacement amount detection device is ΔX, and the amount of displacement in the direction perpendicular to the disk surface of the disk body is ΔY. When the light scattered or reflected in a direction having an angle θ in a direction perpendicular to the disk surface of the disk body with respect to the radial direction of the body is reflected by the first mirror of the mirror unit, the actuator is , And (ΔX × cos θ−ΔY × sin θ) / 2 and (ΔX, respectively) in the direction of the optical axis of the light scattered or reflected by the surface of the outer peripheral portion of the disc body and the direction perpendicular thereto. A disc body outer periphery inspection apparatus characterized by being moved by × sinθ + ΔY × cosθ) / 2.
However, θ is positive in the downward direction with respect to the radial direction of the disc body.   The disk body outer periphery according to claim 1, wherein the second mirror of the mirror part is provided such that a reflection surface thereof is inclined by 90 ° with respect to the reflection surface of the first mirror. Inspection device.   The first mirror of the mirror part is arranged such that a reflection surface thereof is inclined by 45 ° with respect to an optical axis of light scattered or reflected on the surface of the outer peripheral part of the disc body. The disc body outer periphery inspection device according to claim 2, wherein   The displacement amount detecting device includes a displacement amount in the radial direction of the disc body at a position upstream of a predetermined angle in the rotation direction of the disc body from the inspection position of the outer peripheral surface of the disc body, and the disc. The disc body outer periphery inspection device according to any one of claims 1 to 3, wherein a displacement amount in a direction perpendicular to the disc surface of the body is detected. The actuator includes a first drive mechanism that moves the mirror portion in the direction of the optical axis of light scattered or reflected on the surface of the outer peripheral portion of the disc body, and a second drive that moves the mirror portion in a direction orthogonal thereto. With a mechanism,
The disk body outer periphery inspection device according to any one of claims 1 to 4, wherein the first drive mechanism and the second drive mechanism are independently driven.

Images