JPH11297788A - Substrate position detection device and substrate-treating device with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate position detection device for detecting a central position in a surface, with a simple configuration for alignment. SOLUTION: A substrate position detection device is provided with a substrate 1, a support arm 9, a motor 1b for advancing and retreating, and peripheral edge detection parts 17a-17d that carry a circular substrate W which is supported by the support arm 9 in an arc shape for the outer shape of the circular substrate W, are arranged so that the center of the above arc matches the central position of the circular substrate W when the center position matches a target transfer position, and detect the peripheral edge of the circular substrate W. Then, the deviation from the central position of the circular substrate W and the reference central position is obtained based on drive distance, when the peripheral edge detection parts 17a-17d detect a peripheral edge and the mounting position of the peripheral edge detection parts 17a-17d and the motor 1b for advancing and retreating and the substrate 1 are controlled, so that the deviation can be canceled for transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a substrate position detecting device for detecting a center position in a plane of a circular substrate such as a semiconductor wafer formed in a circular shape in plan view, and a substrate processing apparatus provided with the same.

[0002]

2. Description of the Related Art In a conventional substrate position detecting apparatus of this type (also referred to as a pre-alignment station), for example, a circular substrate is supported on a rotating support portion, and a blur of a peripheral portion is one-dimensionally imaged while rotating the circular substrate. A center position in a plane is obtained by detecting with a sensor, or the entire surface of a circular substrate is photographed using an imaging device, and image processing is performed to obtain the center position. The center position thus obtained may be a reference center position that matches the target position of the transfer destination if the circular substrate is transferred as it is, but these may be shifted due to various factors. . In this case, inconvenience occurs at a transfer destination such as a substrate processing unit or a substrate storage unit provided in a substrate processing apparatus or the like. In order to prevent this, a position where the center position of the circular substrate is aligned with the reference center position. Matching is performed.

[0003]

However, in the case of the conventional example having such a configuration, a mechanism for rotating the substrate and devices such as a one-dimensional image sensor and a video camera are required. There is a disadvantage that it is complicated.

Further, a substrate processing apparatus provided with such a substrate position detecting device includes a substrate storing section for storing an unprocessed circular substrate or a processed circular substrate, a coating process and a developing process performed while rotating the circular substrate. Processing, or a plurality of substrate processing units that perform heat processing, between the substrate storage unit and the substrate processing unit,
Generally, a substrate transport mechanism for transporting a circular substrate between substrate processing units is provided.

[0005] The substrate transport mechanism temporarily transports the supported circular substrate to the substrate position detecting device during the transportation. If the center position of the circular substrate detected here is deviated from the reference center position, particles are generated due to blurring during the rotation process, or the periphery of the circular substrate sliding with the member of the substrate storage unit during storage. In order to prevent inconvenience, the circular substrate is positioned so that the center position of the circular substrate coincides with the reference center position, and is then supported by the substrate transport mechanism. When processing a circular substrate in this way, it is necessary to go through a substrate position detection device in order to perform positioning during transport,
There is a problem that the throughput is reduced.

The present invention has been made in view of such circumstances, and detects a position of at least three circular arcs when a circular substrate is moved, so that the center in the plane can be formed with a simple configuration. It is an object of the present invention to provide a substrate position detecting device capable of detecting a position and performing alignment.

Another object of the present invention is to provide a substrate processing apparatus capable of improving the throughput by performing positioning during transfer without transferring a circular substrate to a specific place for positioning. The purpose is to do.

[0008]

The present invention has the following configuration in order to achieve the above object. That is, the substrate position detecting device according to claim 1 is a substrate position detecting device for detecting a center position in a plane of a circular substrate, wherein the circular substrate is formed in an arc shape according to the outer shape of the circular substrate. When the circular substrate is moved, the circular substrate is disposed so that the center of the arc coincides with the center position of the circular substrate, and at least three peripheral edge detecting means for detecting the peripheral edge of the circular substrate; The center position of the circular substrate is obtained based on the moving distance of the circular substrate at the time when the peripheral edge detecting means detects the peripheral edge of the circular substrate, and the mounting position of each of the peripheral edge detecting devices, and the reference is based on the center of the arc. Control means for obtaining a deviation from the center position.

Further, a substrate position detecting apparatus according to a second aspect of the present invention is the substrate position detecting apparatus according to the first aspect, wherein four peripheral edge detecting means are provided.

Further, the substrate processing apparatus according to claim 3 is
A substrate processing apparatus that performs a predetermined process on a circular substrate, a base that is configured to be movable in a horizontal plane, and a support arm that is disposed on the base and supports the circular substrate in a horizontal posture. A substrate transport mechanism having forward / backward driving means for driving the support arm forward / backward, a substrate processing unit for performing a predetermined process on the circular substrate, and an arc shape in accordance with the outer shape of the circular substrate;
In addition, when the circular substrate supported by the support arm is at the target position of the transfer destination, at least three of the circular substrates are arranged so that the center of the circular arc coincides with the center position of the circular substrate, and the periphery of the circular substrate is detected. And a driving distance of the advance / retreat driving means at the time when each of the peripheral detecting means detects the periphery of the circular substrate supported by the support arm when the support arm of the substrate transfer mechanism is moved forward and backward. And the center position of the circular substrate supported by the support arm is determined based on the mounting position of each of the peripheral edge detecting means, and a deviation from a reference center position with respect to the center of the arc is determined. And control means for controlling the substrate transfer mechanism so as to cancel out and transporting the circular substrate to the substrate processing unit.

Further, the substrate processing apparatus according to claim 4 is
4. The substrate processing apparatus according to claim 3, wherein each of the peripheral edge detecting means is provided on the base.

[0012]

The operation of the first aspect of the invention is as follows. The peripheral edge detecting means are arranged in an arc shape in accordance with the outer shape of the circular substrate at the target position, and the number thereof is at least three. Therefore, the center of the arc is determined in advance from these positional relationships. Furthermore, the center of the arc is set to be a reference center position that matches the center position of the circular substrate when the circular substrate is at the target position. When the circular substrate moves, the peripheral edge of the circular substrate is detected by each peripheral detecting means. The control means determines the center position of the circular substrate based on the moving distance of the circular substrate at the time when each peripheral edge detecting means detects the peripheral edge of the circular substrate and the mounting position of each peripheral edge detecting means whose position is known in advance, A deviation from a known reference center position is determined. If the circular substrate is transported so as to cancel this deviation, it can be transported so that the same result as when the circular substrate is transported in a state where the center position of the circular substrate coincides with the reference center position is obtained.

According to the second aspect of the present invention, a V-shaped notch indicating a crystal orientation or the like is formed in the peripheral portion of the circular substrate, so that three edge portions are formed. In some cases, one of the detecting means may erroneously detect the peripheral edge of the circular substrate, but if four peripheral detecting means are provided, at least three peripheral positions can be normally detected.

According to the third aspect of the present invention, when the support arm of the substrate transfer mechanism supporting the circular substrate is moved forward and backward by the advance / retreat driving means, the peripheral edge of the circular substrate is detected by each peripheral edge detecting means. Is done. The control means determines the center of the circular substrate supported by the support arm based on the driving distance by the advance / retreat driving means at the time when each peripheral edge detecting means detects the peripheral edge of the circular substrate and the mounting position of each peripheral edge detecting means. You can ask. Therefore, the deviation from the previously determined reference center position is obtained, and by controlling the substrate transfer mechanism to cancel the deviation and transferring the circular substrate to the substrate processing unit, the center position of the circular substrate becomes the reference center position. It can be conveyed so as to obtain the same result as when conveyed in a matched state.

According to the fourth aspect of the present invention, since each of the peripheral edge detecting means is provided on the base which moves together with the support arm, the position of the base which can be freely moved in a horizontal plane is determined. The center position can be detected by moving the support arm back and forth.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. <Substrate Position Detector> FIG. 1 is a plan view showing a schematic configuration of a substrate position detector according to the present invention, FIG. 2 is a side view thereof, and FIG. 3 is a front view thereof.

A circular substrate W having a circular shape in plan view is supported in a horizontal posture by a bending and stretching arm 3 provided on an upper portion of a base 1. The base 1 is configured to be able to turn around the turning axis P0 together with the bending / extending arm 3 by driving the turning motor 1a. The bending / extending arm 3 is a first arm 5 mounted on the base 1 so as to be rotatable about a rotation axis P1.
A second arm 7 rotatably mounted on a rotation axis P2 at the distal end of the first arm 5;
And a support arm 9 rotatably mounted around the rotation axis P3 at the tip of the support arm. The first arm 5 is driven by rotating the forward / backward motor 1b built in the base 1.
Rotates around the rotation axis P1, and the second arm 7 rotates around the rotation axis P2.
Around the first arm 5 in the opposite direction to the support arm 9
The first arm 5, the second arm 7, and the support arm 9 are provided with a timing belt (not shown) so as to rotate around the rotation axis P3 in the direction opposite to the second arm 7. As a result, the support arm 9 moves forward and backward linearly (two-dot chain line in the figure). A U-shaped support portion 9a is formed on the distal end side of the support arm 9. Four projections 9b are formed on the upper surface of the support portion 9a,
The circular substrate W is configured to abut and be supported by point contact.

The above-described motor 1b, the first arm 5, and the second arm 7 correspond to the forward / backward drive means of the present invention.

A portal frame 11 is mounted on the upper surface of the base 1 in a direction in which the support arm 9 advances and retreats. The central portion of the gate-shaped frame 11 is formed in an arc shape in plan view so as to cover the peripheral portion of the circular substrate W, and the four light projecting portions 13 are embedded in this portion so as to emit light downward. Have been. Further, four light receiving units 15 for receiving irradiation light from above are embedded at positions facing the respective light projecting units 13. The light projecting unit 13 and the light receiving unit 15 facing each other are paired with a peripheral edge detecting unit 17 (first to
Fourth detection units 17a to 17d) are configured, and each edge detection unit 1
Reference numeral 7 corresponds to the peripheral edge detecting means in the present invention. The peripheral edge detecting section 17 only needs to be able to detect the peripheral edge of the circular substrate W, and may have a configuration in which the light projecting section 13 and the light receiving section 15 are attached to each other in a reverse manner, or may be configured by a reflective sensor. You may do so.

The configuration of the peripheral edge detecting section 17 will be described with reference to FIG. The light projecting unit 13 includes a light source unit 13a such as an infrared light emitting diode or a laser, and a lens 13b that converges irradiation light from the light source unit 13a. The light receiving unit 15 includes a lens 15a that converges the irradiation light, and a two-divided sensor 15b that receives the converged irradiation light.
This two-divided sensor 15b is, as shown in FIG.
The light receiving portions are a first light receiving portion 15ba and a second light receiving portion 15b.
b.

Each of the edge detecting sections 17 (17a to 17d)
As shown in FIG. 6, it is connected to the control unit 21, and a signal of each light receiving unit 15 is given to the control unit 21. The control unit 21 includes the above-described turning motor 1a.
, A motor 23 for moving forward and backward, and a memory 23 storing a mathematical expression, a control program, and the like to be described later.

The first light receiving portion 15ba of the two-divided sensor 15b
And signals A and B from the second light receiving unit 15bb are shown in FIG.
As shown in (b), it changes according to the positional relationship between the periphery of the circular substrate W (indicated by the two-dot chain line) and the two-divided sensor 15b.

That is, when the peripheral edge of the circular substrate W is at the position t1, the first light receiving portion 15ba and the second light receiving portion 15ba
Since the irradiation light from the light projecting unit 13 is incident on the entire surface of both bb and bb, the signal A (solid line in the figure) from the first light receiving unit 15ba is also the signal from the second light receiving unit 15bb as shown in FIG. B (dotted line in the figure) has the same signal level. When the peripheral edge of the circular substrate W moves from the position t1 to the position t2, the second
Since the light receiving area of the light receiving section 15bb gradually decreases and finally becomes zero, the signal A remains unchanged, but the signal B gradually decreases and becomes zero. Further, the circumference of the circular substrate W is changed from t2 to t3.
, Since the light receiving area of the first light receiving portion 15ba gradually becomes zero, the signal A from the first light receiving portion 15ba also gradually decreases to zero.

The controller 21 obtains an output signal R = (AB) / (A + B) based on the signals A and B. The output signal R is as shown in FIG. 5C, as is apparent from the signal (A-B) shown by the dashed line and the signal (A + B) shown by the dashed line in FIG. 5B. . In this way, the output signal R obtained from the signals A and B of the first light receiving unit 15ba and the second light receiving unit 15bb of the two-divided sensor 15b is monitored, and when the signal level becomes "1", the control unit 21 Is determined to be at the time of detecting the periphery of the circular substrate W.
As described above, since the control section 21 normalizes the signals A and B from the two-divided sensor 15b and obtains the output signal R for judging the edge detection, the light intensity of the light projecting section 13 fluctuates due to aging or the like. However, the peripheral edge can be accurately detected without being affected by the influence.

If the change in the light intensity of the light projecting section 13 can be compensated, a single light receiving section may be used instead of the two-divided sensor 15b of the light receiving section 15.

Referring to FIG. 1st peripheral edge detection part 17a-
The fourth peripheral edge detecting portion 17d is attached to the portal frame 11 so as to form an arc having a radius r in accordance with the outer shape of the circular substrate W, and their center positions are supported by the support arm 9. upon transporting the circular the substrate W, reference center position CP to the center position CP is located on the trajectory of the center position CP when matching the transport destination of the target position CP _o
It is set to be _ref . In addition, the first peripheral edge detecting section 17a, the second peripheral edge detecting section 17b, and the third peripheral edge detecting section 17
c, each mounting position of the fourth peripheral edge detecting unit 17d is L1
(X1, y1), L2 (x2, y2), L3 (x3, y
3), L4 (x4, y4).

The reference center position CP _ref (x, y)
Are the mounting positions L1 to L1 of the peripheral edge detecting portions 17a to 17d.
It can be obtained from L4 as follows.

Using the first peripheral edge detecting section 17a, the second peripheral edge detecting section 17b, and the third peripheral edge detecting section 17c, the center position C
From the P _ref , the first peripheral edge detecting section 17a and the second peripheral edge detecting section 17
Assuming that each distance to b is equal to and equal to the radius r, the following equation (1) holds. (X1-x) ^2- (y1-y) ² = (x2-x) ^2- (y2-y) ² (1)

Similarly, assuming that the respective distances from the center position CP _ref to the second peripheral edge detecting section 17b and the third peripheral edge detecting section 17c are equal to the radius r and equal, the following equation (2) is established. (X2-x) ^2- (y2-y) ² = (x3-x) ^2- (y3-y) ² (2)

Further, assuming that the respective distances from the center position CP _ref to the first peripheral edge detecting section 17a and the third peripheral edge detecting section 17c are equal to the radius r and equal, the following equation (3) is established. (X1-x) ^2- (y1-y) ² = (x3-x) ^2- (y3-y) ² (3)

From the relations of the above equations (1) to (3), the x and y coordinates of the reference center position _CPref and the radius r thereof can be obtained by the following equations.

[0032]

(Equation 1)

The reference center position CP _ref obtained as described above is stored in the memory 23 in advance. Also,
The memory 23 also stores the driving amount of the forward / backward motor 1b when the peripheral edge is simultaneously detected by each of the peripheral edge detection units 17 when the circular substrate W is transported in a state where there is no displacement.

Although details will be described later, the control unit 21 includes the first peripheral edge detection units 17a to 17
Positional relationship L of four peripheral edge detecting units 17 of peripheral edge detecting unit 17d
The center position of the circular substrate W supported by the support arm 9 based on each of 1 to L4, the drive amount of the forward / backward motor 1b at the time when they detect the periphery of the circular substrate W, and the above formula (CP ′) can be obtained. Then, the deviation (ΔCP) from the reference center position CP _ref which is known in advance is obtained, and the circular substrate W is advanced by controlling the base 1 and the forward / backward motor 1b so as to cancel the deviation (ΔCP). Even if the center position (CP ') is shifted from the reference center position _CPref at this time, the same result can be obtained as in the case of transporting the circular substrate W in a state where they match.

Next, referring to the flowchart of FIG.
The operation of the substrate position detecting device configured as described above will be described.

The circular substrate W is supported by the support arm 9 as shown in FIG.
Is shifted by a certain distance in each of the X and Y directions from the center position (CP) that coincides with the target position CP _O when transported, and this shift is assumed to be ΔCP.

Step S1 (peripheral edge detection) The controller 21 controls the forward / backward motor 1b until all the peripheral edge detectors 17 of the first to fourth peripheral edge detectors 17a to 17d detect the peripheral edge of the circular substrate W. The circular substrate W is driven to advance toward the portal frame 11 side. As described above, since the circular substrate W is supported by the support portion 9a in a state where it is displaced, in this example, the first peripheral edge detecting portion 17a first detects the peripheral edge (the state shown in FIG. 9), and then the second peripheral edge detecting portion 17a detects the peripheral edge. 2 rim detecting section 17b, 3rd rim detecting section 17c, 4th rim detecting section 17d
Will be detected in this order.

Step S2 (Determine the Center Position and Radius) The driving amount of the forward / backward motor 1b at the time when the first peripheral edge detecting section 17a detects the peripheral edge, and the driving amount stored in the memory 23 when there is no displacement. Similarly, the difference between the driving amounts of the second edge detecting unit 17b, the third edge detecting unit 17c, and the fourth edge detecting unit 17d is also obtained. These Y
The difference between the coordinates, x of the center position CP 'with new coordinate values obtained by subtracting from the Y-coordinate (y1 to y4) of the peripheral detecting portions 17 of the formula for obtaining a reference center position CP _ref as described above, y
Find coordinates and radius r. Since four perimeter detectors 17 are provided, there are four combinations of three required to find the center. Therefore, the center position and the radius are obtained from four types of equations based on the above-described equations.

Step S3 (Radius Exceeds Error Range?) A notch may be formed at the periphery of the circular substrate W. If the periphery detection unit 17 is located at this portion, the center can be determined accurately. Can not. Then, in order to remove the influence of the notch, the four radii r obtained are compared. Then, if the calculated radius r exceeds the error range, the process proceeds to step S4, and the calculated center position is excluded from the subsequent processing.

Step S5 (Determining Deviation) When the processing has shifted from step S3, the four center positions CP 'are selected. When the processing has shifted from step S4, the three center positions CP' are selected. The deviation ΔCP from the reference center position CP _ref is obtained by using either of them.

Step S6 (convey so as to cancel the deviation) The control unit 21 controls the turning motor 1a and the forward / backward motor 1b so as to cancel the deviation ΔCP obtained as described above, and the position is shifted. Transports the circular substrate W supported by the support arm 9 (see FIG. 10). Specifically, since the angular deviation between the target position CP _O and the rotation axis P0 in a state where the positions are shifted as shown in FIG. 9 is Δθ,
The control unit 21 drives the turning motor 1a so as to cancel the angle deviation Δθ. Then, by controlling the advancement distance retractable arm 1b in accordance with the deviation Delta] CP, it can be transported to the center position CP of the circular substrate W 'coincides with the target position CP _O.

In the above embodiment, the base 1 is turned by the turning motor 1a. However, the base 1 may be moved in the horizontal direction (left / right / back and forth). In this case, the base 1 may be moved right and left according to the deviation ΔCP, and the support arm 9 may be advanced according to the deviation ΔCP. Further, instead of the bending arm 3 as described above, a supporting arm 9 that linearly advances and retreats without bending may be used.

[0043] In the above description, but so as to detect the center position CP 'when to advance the circular substrate W to the target position CP _O, centered upon Eject circular substrate W from the target position CP _O detecting the position CP ', it may be the position adjustment in which advances the circular substrate W to next target position CP _O.

Further, the substrate 1 and the portal frame 11 provided with the peripheral edge detecting portion 17 may be formed separately to constitute a substrate position detecting device.

<Substrate Processing Apparatus> A substrate processing apparatus provided with the above-described substrate position detecting apparatus will be described with reference to FIG. This figure is a plan view showing a schematic configuration of the substrate processing apparatus.

The substrate processing apparatus 100 has a substrate transport mechanism 110 provided with the above-described substrate position detecting device at a central portion, around which an unprocessed or processed circular substrate W
And a substrate processing unit 150 that performs a spin coating process, a spin development process, and the like.

The substrate processing apparatus 1 configured as described above
00, when the substrate transport mechanism 110 transports the circular substrate W, the circular substrate W always passes below the gate-shaped frame 11 provided with the peripheral edge detection unit 17. Of the center position CP ′ of the
Find P. Then, by conveying to cancel the deviation Delta] CP, to correct the positional deviation while the position detection in the middle of the conveyance can be conveyed, the center position CP of the circular substrate W 'and the target center position CP _O Can be matched. Therefore, the position of the circular substrate W can be detected regardless of the position of the substrate transport mechanism 110 in the substrate processing apparatus 100, and the substrate is moved to a specific position (alignment unit) for performing position detection as in the conventional apparatus. There is no necessity, and the throughput can be improved.

In the above apparatus, the substrate transport mechanism 110
Are integrated with the substrate position detecting device, but they may be formed separately as in a substrate processing device 200 shown in FIG.

That is, the gate-type frame 11 including the substrate transport mechanism 210, the substrate storage section 230, and the substrate processing section 250, and including the peripheral edge detection section 17,
It is configured by being arranged on the transport path of the substrate processing section 250. In the apparatus configured as described above, for example, the substrate transport mechanism 21
When 0 carries out the circular substrate W from the substrate storage device 230 and carries the circular substrate W into the substrate processing section 250, the base 1 and the support arm 9 may be controlled in accordance with the deviation ΔCP.

[0050]

As is clear from the above description, according to the substrate position detecting apparatus of the first aspect, at least three arc-shaped positions are detected when the circular substrate is moved. Therefore, the center position in the plane can be detected with a simple configuration. Therefore, the deviation between the reference center position and the center position when the circular substrate is conveyed and the center position coincides with the target position is obtained, and the circular substrate is conveyed so as to cancel this deviation, whereby the center position of the circular substrate becomes the target position. Positioning can be performed to match the position.

According to the substrate position detecting device of the second aspect, if four peripheral edge detecting means are provided, at least three peripheral positions can be normally detected even if there is a notch, so that the substrate position detecting device can operate normally. The center position of the circular substrate can be detected. Therefore, the inconvenience caused by the notch can be avoided.

According to the third aspect of the present invention, a circular substrate is conveyed to determine a deviation from a reference center position when the center position coincides with the target position of the transfer destination, and the deviation is canceled. By transferring the circular substrate to the substrate processing unit as described above, it is possible to perform positioning such that the center position of the circular substrate matches the target position. Therefore, it is not necessary to once transport the circular substrate to a specific location for alignment, and the throughput can be improved.

According to the substrate processing apparatus of the fourth aspect, the center position of the circular substrate can be detected by moving the support arm back and forth regardless of the position of the base, and the center position can be quickly detected. Can be requested.

[Brief description of the drawings]

FIG. 1 is a plan view showing a schematic configuration of a substrate position detecting device according to the present invention.

FIG. 2 is a side view of the substrate position detecting device.

FIG. 3 is a front view of the substrate position detecting device.

FIG. 4 is a diagram showing a schematic configuration of a peripheral edge detection unit.

FIG. 5 is a diagram illustrating an output change due to a positional relationship between a two-divided sensor and a circular substrate.

FIG. 6 is a block diagram illustrating a schematic configuration of a control system.

FIG. 7 is a diagram illustrating an arrangement of each peripheral edge detection unit.

FIG. 8 is a flowchart showing an operation.

FIG. 9 is a diagram illustrating a state in which a circular substrate is displaced.

FIG. 10 is a diagram provided for explanation of conveyance.

FIG. 11 is a plan view showing a schematic configuration of a substrate processing apparatus according to the present invention.

FIG. 12 is a plan view showing a modification of the substrate processing apparatus.

[Explanation of symbols]

W: circular substrate 1: base 1b: forward / backward motor (forward / backward drive unit) 5: first arm (backward / backward drive unit) 7: second arm (backward / backward drive unit) 9 ... support arm 11: portal frame 13 ... throw Light section 15 Light receiving section 17 Peripheral detecting section (peripheral detecting means) 17a First peripheral detecting section 17b Second peripheral detecting section 17c Third peripheral detecting section 17d Fourth peripheral detecting section 21 Control section (control) Means) 23 ... memory CP ... center position CP _ref ... reference center position CP _O ... target position 100, 200 ... substrate processing apparatus 110, 210 ... substrate transport mechanism 130, 230 ... substrate storage section 150, 250 ... substrate processing section

Claims (4)

[Claims] 1. A substrate position detecting device for detecting a center position in a plane of a circular substrate, wherein the center position of the circular substrate is formed in an arc shape according to an outer shape of the circular substrate, and when the circular substrate is at a target position. At least three perimeter detecting means disposed so that the center of the circular arc coincides with the position, and detecting the perimeter of the circular substrate; and when the circular substrate moves, each of the perimeter detecting means detects the perimeter of the circular substrate. Control means for determining the center position of the circular substrate based on the moving distance of the circular substrate at the time of detection and the mounting position of each of the peripheral edge detecting means, and calculating a deviation from a reference center position with respect to the center of the circular arc And a substrate position detecting device. 2. The substrate position detecting device according to claim 1, further comprising four peripheral edge detecting means. 3. A substrate processing apparatus for performing predetermined processing on a circular substrate, comprising: a base movably configured in a horizontal plane; and a base disposed on the base and supporting the circular substrate in a horizontal posture. A support arm to
A substrate transport mechanism having forward and backward driving means for driving the support arm forward and backward; a substrate processing unit for performing a predetermined process on the circular substrate; an arc shape according to the outer shape of the circular substrate; and When the supported circular substrate is at the target position of the transfer destination, the center of the circular arc is arranged so as to coincide with the center position of the circular substrate, and at least 3 detecting the periphery of the circular substrate
When the support arm of the substrate transport mechanism is advanced or retracted, the drive of the advance / retreat drive means at the time when each of the edge detection means detects the periphery of the circular substrate supported by the support arm. The center position of the circular substrate supported by the support arm is determined based on the distance and the mounting position of each of the peripheral edge detection means, and the deviation from the reference center position with respect to the center of the arc is determined. Control means for controlling the substrate transfer mechanism so as to cancel the deviation and transferring the circular substrate to the substrate processing unit. 4. The substrate processing apparatus according to claim 3, wherein each of said peripheral edge detecting means is provided on said base.