JP2529637Y2 - Substrate rotation holding device - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a substrate rotation holding device,
Particularly, in an apparatus for performing a surface treatment by supplying a required surface treatment liquid to the surface of a wafer while rotating a thin plate-like substrate (hereinafter referred to as a “wafer”) such as a semiconductor substrate or a glass substrate for a liquid crystal or a photomask. The present invention relates to a substrate rotation holding device used.

[0002]

2. Description of the Related Art In general, a substrate rotation holding device is roughly classified into a vacuum chuck type in which one side of a wafer is vacuum-sucked, and a grip chuck type in which an outer edge of a wafer is gripped by three or more gripping claws.

Since the vacuum type can process only one side of the wafer, the latter type of grip chuck is usually used when processing both sides of the wafer.

However, the grip chuck type has a problem that the gripping mechanism is complicated, and when used in a substrate processing apparatus, the mechanism is affected by the chemical solution and the mechanism is corroded.

In order to solve such a problem, the present applicant has already filed a patent application (Japanese Patent Application No. 61-285,752) for improving a rotation holding device of a grip chuck type.
And proposes the following substrate rotation holding device.

FIG. 5 is a plan view of a turntable portion of the rotation holding device, FIG. 6 is a partial longitudinal sectional view taken along line II of the turntable portion of FIG. 5, and FIG. 7 is an operation of a movable chuck pin. FIG. 8 is a diagram schematically showing a state in which a wafer is gripped by each chuck pin.

As shown in FIG. 5, the turntable 1 has six arms 1a extending radially, and a fixed chuck pin 2 and a movable chuck pin 3 are alternately provided at the tip of each arm 1a. It is erected in.

Further, as shown in FIG. 6, the turntable 1 is firmly fixed to the upper flange 4a of the rotary drive shaft 4 with bolts 4b.

The rotary drive shaft 4 has a cylindrical shape, and an arm drive shaft 5 to be described later penetrates the inside thereof in a rotatable manner.

In the middle of each of the chuck pins 2 and 3, there are stepped portions 2a and 3a for mounting the wafer W and wafer gripping portions 2b and 3b provided thereon. The inner surface of the gripping portion 2b is formed so that its cross section becomes a circular arc similar to that of the wafer W, and the inner surface of the gripping portion 3b of the movable chuck pin 3 is formed such that its cross section becomes substantially an figure of eight. .

The wafer W is placed above the gripping portions 2b, 3b of the chuck pins 2, 3 respectively.
b so that it can be easily introduced into the substrate.
c and 3c are provided.

The movable chuck pin 3 is rotatably supported by the arm 1a, and has a swing arm 6 provided below. The swing arm 6 is connected to a disk 5a attached to the upper part of the arm drive shaft 5 via an operation link 7, and the arm drive shaft 5 is moved relative to the turntable 1 in the direction of arrow A. When rotated (FIG. 5), the operation link 7 moves from the position indicated by the two-dot chain line to the position indicated by the solid line, whereby the swing arm 6 swings outward with respect to the turntable 1, and each movable chuck pin 3 moves. Is rotated in the direction of arrow B.

The cross-sectional shape of the inner surface of the gripper 3b of the movable chuck pin 3 is formed substantially in the shape of an eight as described above. (FIG. 7) abuts against the outer edge Wa of the wafer W and urges it toward the center of the turntable 1, and the wafer W is firmly fixed to the turntable 1 by the chuck pins 2 and 3 (FIG. For convenience of explanation, each chuck pin 2,
3 are shown in section. ).

In this manner, while the wafer W is fixed to the turntable 1, the rotary drive shaft is rotated at high speed by drive means (not shown). The predetermined wafer processing can be performed by injecting the processing liquid.

[0015]

However, in the above-described substrate rotation holding device, if the chuck pins 2 and 3 do not grip the wafer W firmly, the rotation of the turntable 1 causes the wafer to rotate. W is thrown out of the turntable 1, and not only the wafer W is damaged, but also the device itself is damaged, and in some cases, a situation may occur in which personal injury may occur.

In particular, in an automated substrate processing apparatus, the transfer of the wafer W to the turntable 1 is all operated by a transfer device by a machine, so that the wafer W can be correctly handled by the stepped portion of each chuck pin. It is necessary to confirm that the device is placed on 2a and 3a and that it is securely grasped by each of the grasping portions 2b and 3b before operation.

The situation where the wafer W is not gripped by the chuck pins 2 and 3 as described above occurs because the transfer device places the wafer W at a position shifted from the predetermined position of the chuck pins 2 and 3. This is caused when W is caught by the tip of any of the chuck pins 2 and 3 or the tapered portions 2c and 3c and is held in an oblique state.

Therefore, it is only necessary to be able to detect such an oblique grip state in advance, but it is conceivable to use a photoelectric device as a detecting means therefor. For example, at least two sets of photoelectric devices including a pair of light projecting means and light receiving means are installed outside the turntable 1. The detection light is made parallel to the turntable 1 and slightly above the steps 2a and 3a of each check pin (at least the thickness of the wafer W). Since the stop position is controlled so as to be always constant, the photoelectric device is installed so that the plurality of detection lights are emitted from different directions between the check pins.

If the wafer W is obliquely placed on the chuck pins 2 and 3, at least one of the plurality of detection lights is blocked by the wafer W.
Thereby, it is possible to know the abnormality of the chuck state.

However, according to such a detection method, depending on the position of the photoelectric device, there is no case where the detection light is not blocked even though the wafer W is tilted. In the worst case where three or more chuck pins 2 and 3 are horizontally mounted on the head, all the detection light is not blocked, and the detector determines that the grip is normal. Further, when the present rotation holding device is used by being incorporated in a substrate processing device or the like, a large amount of highly corrosive processing liquid is used in the device, and the sensor section of the photoelectric device is immediately corroded. There is a disadvantage that it will.

In view of the fact that the gripping mechanism in the prior art is configured to grip by rotating the arm drive shaft 5 relative to the rotary drive shaft 4, the relative rotation angle is detected. By doing so, the wafer W
Applicants have devised a method of preventing the slanting gripping.

That is, as shown in the schematic diagram of FIG. 9A, the wafer W
a, 3a, the contact surface P (FIG. 7) of the gripping portion 3b of the movable chuck pin 3 surely contacts the outer edge Wa of the wafer W when it is horizontally held. ,
As shown in FIG. 8, the movable chuck pin 3 cannot rotate at a certain angle α or more, so that the arm drive shaft 5 also rotates relative to the turntable 1 at a certain angle β or more (see FIG. 3). Can not.

On the other hand, as shown by a two-dot chain line in FIG. 9A, when a part of the wafer W is hooked on the upper end of one of the chuck pins 2 and 3 and is placed obliquely with respect to the turntable 1, Each movable chuck pin 3 can freely rotate, and the arm drive shaft 5 can also rotate beyond the predetermined angle β. Therefore,
If the rotation angle detector is set so as to emit an abnormal signal when the relative rotation angle of the arm drive shaft 5 becomes equal to or more than β,
It is possible to know that the wafer W is not held at the correct position, and it is possible to prevent an accident.

According to such a method, the rotation angle detector can be provided not in the substrate processing section but below the arm drive shaft 5 which is isolated therefrom, so that it is not affected by the processing liquid or the like at all. Has an excellent effect.

However, even with such a method, there is a case where the rotation angle detector determines that the wafer W is normal even though the gripping of the wafer W is not normal. It was discovered that there was.

That is, a part of the outer edge Wa of the wafer W
As shown in FIG. 9B, the tapered portion 3c of the movable chuck pin 3
When the movable chuck pin 3 is
Is rotated, the tapered surface of the tapered portion 3c comes into contact with the outer edge Wa of the wafer W, and the rotation of the movable chuck pin 3 stops at that position. It has been found that there is a problem that the rotation angle detector does not emit an abnormal signal.

The present invention solves the above-mentioned problems,
An object of the present invention is to provide a substrate rotation holding device that can reliably confirm a gripping state of a wafer with a simple structure.

[0028]

In order to achieve the above object, a rotation holding device for a substrate according to the present invention includes a turntable, driving means for rotating the turntable, and a substrate attached to the turntable. It comprises at least three chuck pins for gripping the outer edge, each chuck pin comprising a gripper for abutting against and gripping the outer edge of the substrate, and a substrate introducing portion for guiding the substrate to the gripper, and The at least one chuck pin is a movable chuck pin rotatably supported by the rotary table, and the cross-sectional shape of the gripping portion urges the outer edge of the substrate toward the center thereof by rotation of the movable chuck pin. In the substrate rotation holding device formed so as to perform the operation of holding and releasing the substrate by rotating the movable chuck pin, the degree of rotation of the movable chuck pin Flip provided with a detection means for determining the holding state of the substrate, the substrate introducing portion of the movable chuck pin, the portion abutting the substrate edge, characterized in that a notch.

[0029]

When a part of the outer edge Wa of the wafer W is caught by the introduction portion of the movable chuck pin, a notch is provided in a portion of the introduction portion which comes into contact with the substrate by rotating the movable chuck pin. Therefore, the movable chuck pin can rotate freely without being restrained, and the detecting means for determining the holding state of the substrate according to the degree of rotation of the movable chuck pin can surely hold the wafer W with each chuck pin. Is not normal.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a substrate rotation holding device according to the present invention will be described in detail with reference to the drawings, but the technical scope of the present invention is not limited thereto. is there.

In the following drawings, those denoted by the same reference numerals as those in FIGS. 5 to 9 have the same contents, and the description thereof will be omitted.

FIG. 1 is a partial longitudinal sectional view showing a substrate processing apparatus incorporating an embodiment of the substrate rotation holding apparatus according to the present invention.

The rotary drive shaft 4 projects into a cup 12 which defines a processing chamber of the substrate processing apparatus 11, and has a rotary head 13 on the upper part. Fixed.

The rotary drive shaft 4 is formed in a cylindrical shape, and an arm drive shaft 5 penetrates the inside thereof. A disk 5a is attached to the upper end of the arm drive shaft 5, and this disk 5a
Swing arm 6 provided below movable chuck pin 3
Are connected by an operation link 7.

FIG. 2 shows the shape of the movable chuck pin 3 supported by the arm 1a of the turntable 1. As shown in FIG.

FIG. 2A is a front view of the movable chuck pin 3, in which a tapered portion 3c (a hatched portion in the drawing) above a portion of the gripping portion 3b in contact with the wafer W is cut to form a cutout 3d. And has the appearance as shown in the perspective view of FIG. 2B.

Since the notch 3d is provided in the tapered portion 3c of the movable chuck pin 3 as described above, the outer edge Wa of the wafer W is inclined by the tapered portion 3c as shown in FIG. 8B. Even when the movable chuck pin 3 is rotated, the outer edge Wa of the wafer W enters the notch 3d and the rotation of the movable chuck pin 3 is not restricted (FIG. 2).
C). Therefore, the rotation of the arm drive shaft 5 is not restricted and the rotation angle becomes equal to or larger than β, and the rotation angle detector 25 described later reliably detects abnormality in the chuck state.

Returning to FIG. 1, the rotary drive shaft 4 includes a bearing 14
, Is rotatably held on a base 15, and is rotationally driven by a pulley 16 attached below and a belt 18 hung on a driving pulley 17 a of a driving motor 17.

An engagement hole 19a is provided at a predetermined position around a disk-shaped flange 19 attached to the rotary drive shaft 4, while an engagement hole 19a is provided at a position corresponding to the flange 19 on the base 15. Is provided with a clamp device 20. The clamp device 20 includes an actuator 20a and a rod 20b which is driven left and right by the actuator 20a.
c is engaged with the engagement hole 19a of the flange 19 so that the turntable 1 can be fixed at a predetermined position.

A flange 21 is formed at the lowermost end of the rotary drive shaft 4, and a pin 21a projects downward from the flange 21. On the other hand, a pin 22 is also provided in the arm drive shaft 5 in the horizontal direction, and between the pin 21 a and the pin 22,
A tension spring 23 is provided (FIG. 3). This allows
The arm drive shaft 5 is urged in the direction A in FIG. 5, and the movable chuck pins 3 are in a state of always chucking the wafer W.

Reference numeral 24 denotes a chuck release device.
It comprises an actuator 24a and a rod 24b. To release the chuck state, after the rotation of the turntable 1 is stopped at a fixed position, the rotation drive shaft 4 is fixed by the clamp device 20,
This is achieved by the actuator 24a of the chuck releasing device 24 extending the rod 24b, thereby urging the pin 22 in the direction opposite to the tension direction of the tension spring 23.

FIG. 3 shows a view of the pin 22 of the arm drive shaft 5 of FIG. 1 as viewed from above.

A stopper pin 22a is provided on the arm drive shaft 5 so that the arm drive shaft 5 does not rotate more than necessary.
Engages with the pin 21a to stop the relative rotation of the arm drive shaft 5 (provided that γ ≧ β).

A rotation angle detector 25 for detecting the relative rotation angle of the arm drive shaft 5 is provided at the lowermost part of the arm drive shaft 5. As shown in FIG. 3, the rotation angle detector 25 includes a light-shielding disk 25a and a photoelectric sensor 25b having a light projecting unit and a light receiving unit. The relative rotation angle of the arm driving shaft 5 is constant from a reference position. When the angle β or more, the light-shielding disk 2
5a shields the optical axis 25c of the photoelectric sensor 25b fixed to the base 15, and a signal to that effect is sent to the control device 26 from the photoelectric sensor 25b. The controller 26 receives the signal, issues an alarm, and notifies the operator that the wafer W is not normally held.

In the above, the turntable 1 is controlled by the control device 26.
And it is configured to be always stopped and fixed at a fixed position by the clamp device 20, so that the photoelectric sensor 25b
Can accurately detect the relative rotation angle of the arm drive shaft 6 even if it is attached to the base 15 as in this embodiment.

However, in this case, since the chuck state cannot be detected while the turntable 1 is rotating, if it is desired to always check the chuck state during the rotation, the light-shielding disk is required. 25a is attached to the arm drive shaft 5 immediately below the flange 19, and the photoelectric sensor 25b is fixed to the flange 19, and the signal of this photoelectric sensor is received by a small transmitter provided separately on the flange 19, separately. May be transmitted to the device.

The light-shielding disk 25a may be a simple light-shielding plate for shielding only necessary portions. However, at high speed rotation, the open portion 25d is made as small as possible so that there is no shaft deviation due to imbalance around the axis. It is more desirable to form. For example, as shown in FIG. 4, only the first open part 25e and the second open part 25f are formed small in the open part of the light-shielding disk 25a, and the control is performed as follows. That is, the rod 24b of the actuator 24a extends as shown in FIG.
Further, when the first open portion 25e of the light-shielding disk 25a is at a position where the optical axis 25c of the photoelectric sensor 25b is not shielded, in other words, the rod 24b is in the extended state, and the light receiving means of the photoelectric sensor 25b receives the light. In this state, the apparatus is capable of supplying and discharging the wafer W.
Next, as shown in FIG. 4B, when the rod 24b is in the contracted state and the light receiving means of the photoelectric sensor 25b is not receiving light, the wafer W is chucked and rotatable. Also, as shown in FIG. 4C, when the rod 24b is in the contracted state and the light receiving means is in the light receiving state by the second open portion 25f, it is in the abnormal gripping state.

Further, the magnitude of the above-mentioned constant angle β is determined by the time that the movable chuck pin 3 rotates from the reference position and the contact surface P of the holding portion 3b contacts the outer edge Wa of the wafer W as described above. It is uniquely determined by the angle α (FIG. 8).

Reference numeral 27 denotes a known encoder device for detecting the rotational speed of the rotary drive shaft 4 and the stop position. A disk 27a having a number of notches around it and an optical axis at the positions of the notches. And a photoelectric sensor 27b. The signal from the encoder device 27 is counted by the control device 26, thereby controlling the rotation speed, and the turntable 1 is always stopped at a fixed position, and the clamp device 20 is stopped.
Is controlled to be clamped.

The actuator 29 located below the base 15 lifts the turntable 1 together with the base 15 when the holding device receives the wafer W from a wafer transfer device (not shown). ′ Is a guide rod for that purpose, which penetrates the base 15 slidably.

Reference numerals 31 and 32 denote processing liquid supply nozzles for supplying a chemical solution, pure water, and the like to the front and back surfaces of the wafer W, and are connected to a processing liquid supply device (not shown).

Note that all operations of the substrate processing apparatus 11 are as follows.
The operation is controlled by the control device 26, and the operation will be briefly described below.

First, the wafer W is transferred by wafer transfer means (not shown) and is held above the turntable 1. Next, the movable chuck pin 3 is released from chucking by the chuck releasing device 24, the rotary table 1 is moved upward by the actuator 29, and the wafer W is gripped (two-dot chain line in the figure). At this time, the gripping operation by the rotation of the movable chuck pin 3 is performed twice, and the detection by the rotation angle detector 25 is set to be performed at the time of the second gripping operation. Thereby, even if the wafer W is not first correctly placed on the turntable 1, the wafer W can be placed correctly in most cases by the first gripping operation by the movable chuck pins 3; At the time of the second gripping operation, an error check by the rotation angle detector 25 operates to notify an abnormality of the gripping state. Note that such a preliminary gripping operation is not limited to one time, and may be performed several times as necessary.

At this time, if there is an abnormality in the gripping state, the controller 26 issues an abnormality signal by a signal from the rotation angle detector 25 to warn the operator and stop the subsequent substrate processing operation. The operator restarts the operation after placing the wafer W at a correct position by hand.

When it is confirmed by the rotation angle detector 25 that the wafer W has been correctly grasped, the turntable 1 is lowered and returns to the home position, the clamp device 20 is released, and the drive motor 17 drives the rotation. The shaft 4 rotates at a predetermined rotation speed.
The detection signal of the encoder device 27 is sent to the control device 26, and the rotation speed of the rotary drive shaft 5 is feedback-controlled.

When the turntable 1 is rotationally driven, a required processing liquid is supplied from the processing liquid supply nozzles 31 and 32,
Surface treatment of the wafer W is performed.

After the processing, the feedback control
The turntable 1 is stopped so as to be in a fixed position, and the clamp device 2
0, the rotary drive shaft 4 is clamped, and then the turntable 1 is raised by the actuator 29.
The wafer W is transferred to the wafer transfer means, and the operation of the substrate processing ends.

In the above embodiment, the actuators 20, 24, and 29 may be pneumatic or hydraulic, and in particular, the actuator 20 may be an electromagnetic actuator. A screw feed mechanism using a ball screw may be used.

The arm drive shaft 5 for chucking operation
Is the simplest and most reliable method to use the tension spring 23 as in this embodiment,
Not limited to such a method, it is also possible to provide an electromagnet or the like in this portion. Further, a disk for torque load is provided on the arm drive shaft 5, and the disk is provided on the disk against the rotation of the rotary drive shaft 4. By applying a slight mechanical resistance, the rotation drive shaft 4 and the arm drive shaft 5 can be relatively rotated to perform the chucking operation.

Further, the rotation angle detector 25 is not limited to the combination of the light-shielding disk 25a and the photoelectric sensor 25b as in this embodiment.
A limit switch or the like may be provided so as to emit a signal when the pin 22a comes into contact with 1a.

Also, as described above, the degree of rotation of the movable chuck 3 is not indirectly checked by the rotation angle of the arm drive shaft 5. The rotation of the movable chuck 3 can be directly checked by irradiating a light beam from outside to the reflecting mirror and detecting the angle of reflection by an optical sensor which has been subjected to a non-corrosive treatment. It is possible.

Further, the cross-sectional shape of the inner surface of the gripping portion 3b of the movable chuck pin 3 is not limited to an approximately figure eight shape as described above. Keep in mind that the movable chuck pin 3
Any shape may be used as long as the contact surface of the grip portion 3b is close to the center of the turntable due to the rotation in a certain direction. Also, the cross-sectional shape of the holding portion 2b of the fixed chuck pin 2 is not arcuate as described above, but is similar to that of the movable chuck pin 3 in a shape similar to the figure of eight.
Can be more easily inserted.

The number of the chuck pins 2 and 3 of the turntable 1 in the present embodiment is 6 in total so that the wafer W can be securely gripped even when an orientation flat is formed on the outer edge of the wafer W. However, if the wafer is mounted on the turntable 1 by a wafer transfer device capable of positioning by the orientation flat, at least three (of which at least one is a movable chuck pin) are given. It can achieve its purpose.

The present invention can be applied not only to the substrate processing apparatus as in the above embodiment but also to an apparatus for holding and rotating a substrate.

[0065]

As described above, the substrate rotation holding device according to the present invention can rotate the movable chuck pins even if a part of the outer edge Wa of the wafer W is caught on the substrate introduction portion of the movable chuck pins. Since the notch is provided in a portion that abuts on the substrate, the movable chuck pin can rotate freely without being restrained, and determines whether or not the substrate is gripped according to the degree of rotation of the movable chuck pin. The means can surely detect that the holding of the wafer W is not normal.

As a result, it is possible to prevent the wafer W from jumping out and damaging the wafer W itself or the device from being damaged when the substrate rotation holding device rotates at a high speed.

[Brief description of the drawings]

FIG. 1 is a view illustrating a substrate processing apparatus according to an embodiment of the present invention in which a substrate rotation holding apparatus is incorporated.

FIG. 2 is a diagram illustrating the shape of a movable chuck pin according to the present embodiment.

FIG. 3 is a diagram showing a configuration of a part of a chuck release device and a rotation angle detector in the present embodiment.

FIG. 4 is a diagram illustrating the operation of a rotation angle detector.

FIG. 5 is a top view of a portion of a turntable of a conventional substrate rotation holding device.

FIG. 6 is a partial longitudinal sectional view of a turntable portion of the substrate rotation holding device of FIG. 5;

FIG. 7 is a view for explaining a conventional gripping operation of a movable chuck pin.

FIG. 8 is a view showing a state of holding a wafer by a conventional chuck pin.

FIG. 9 is a view showing a state in which a wafer is placed on a turntable.

[Explanation of symbols]

 Reference Signs List 1 rotary table 2 fixed chuck pin 3 movable chuck pin 4 rotation drive shaft 5 arm drive shaft 6 swing arm 7 operation link 11 substrate processing device 12 cup 20 clamp device 21 flange 21a, 22 pin 23 tension spring 24 chuck release device 25 rotation Angle detector 26 Control device 29 Actuator

Claims (1)

(57) [Scope of request for utility model registration] 1. A rotary table, comprising: a rotary table; driving means for driving the rotary table to rotate; and at least three chuck pins attached to the rotary table and gripping an outer edge of the substrate. A movable chuck that includes a gripper that abuts on the outer edge and grips the outer edge, and a substrate introduction unit that guides the substrate to the gripper, and at least one chuck pin is rotatably supported by the rotary table; A pin whose cross-sectional shape is formed so as to urge the outer edge of the substrate toward the center thereof by rotation of the movable chuck pin, and an operation of gripping / releasing the substrate by rotating the movable chuck pin. In the substrate rotation holding device, a detecting means for determining a holding state of the substrate according to a degree of rotation of the movable chuck pin is provided, and the movable chuck is provided. In the substrate introducing portion of Kupyn, the portion abutting the substrate edge, rotating the holding device for the substrate, characterized in that a notch.