JP2633798B2 - Plate-like member holding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate-like member holding device for holding a plate-like member such as a silicon wafer without impact.
More specifically, the present invention relates to a plate-like member gripping device that can flexibly grip the peripheral edge of a plate-like member by a straight-moving type flexible actuator capable of performing a flexible movement.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, many wafer processing apparatuses such as a photographic exposure apparatus, an etching apparatus, and a vapor phase film forming apparatus are used in a dust-free room. Therefore, a silicon wafer as a semiconductor substrate is transferred between these apparatuses. Must. Conventionally, to transport a silicon wafer, the wafer has been gripped by a suction pad using an exhaust pump or the like, and transported by a mechanical movement element such as a motor or a piston mechanism. Here, when approaching the suction pad to the wafer to be gripped (hereinafter, referred to as “wafer approach”), movement by a mechanical movement element has been used.

[0003]

However, the conventional gripping device using the suction pad and the mechanical movement element has the following problems. First, suction pads require a rotary pump for evacuation. Since the rotary pump uses oil for a seal or the like, the cleanliness of the dust-free chamber may be impaired by oil mist. In addition, the suction pad itself may contaminate the suction position of the wafer. Therefore, normally, the back surface of the wafer is sucked. However, depending on the wafer handling during the process, the process surface may have to be sucked in some cases, resulting in a decrease in yield.

[0004] Second, there is a problem due to mechanical motion elements such as a motor and a piston. That is, these are generally rigid structures, and are configured to have a movement and positioning accuracy on the order of microns by such rigidity. If such a rigid motion element hits another member or the like while performing a predetermined motion, a mechanical impact will be generated.
This is hereinafter referred to as “hard movement”.

[0005] In the case of a silicon wafer, when a mechanical shock due to hard motion is applied, an internal defect is generated, which may affect its electrical characteristics. Further, depending on the degree of impact, the wafer itself may be damaged or deformed. Also, particles that are inevitably generated at the time of breakage or deformation may be larger than the processing dimensions of the fine circuit elements to be formed on the wafer, so if they adhere to other wafers, they will interfere with the required fine circuit processing. And lower the yield. For these reasons, mechanical impact on the wafer should be eliminated as much as possible. Therefore, when such a hard movement is used for the movement during the wafer approach,
It is necessary to perform extremely low-speed driving by extremely precise position control and speed control to suppress the occurrence of mechanical shock. However, the piston, which is a mechanical motion element, has a stepping behavior when driven at an extremely low speed, so that the position accuracy is poor and the instantaneous speed is not so slow, so that mechanical impact cannot be eliminated.

On the other hand, in recent years, there have been various flexible actuators capable of performing a flexible movement instead of a hard movement by combining a stretchable material such as rubber and a non-stretchable material such as a reinforcing fiber and supplying compressed air thereto. Proposed (Tanaka, Mechanical Design 36, 8 (1992-7), 32-
39 etc.). Flexible actuators can move straight, bend, bend, and flex depending on the combination of stretchable and non-stretchable materials.
Various movements such as twisting are possible. For this reason, it is considered that a wafer holding device that eliminates the occurrence of mechanical impact is realized by using the flexible actuator for the wafer approach of the wafer holding device.

[0007] However, the conventional flexible actuator is still insufficient for application to a semiconductor manufacturing process. For example, in the case of the curved flexible actuator shown in FIG. 7, since the actuator itself is basically composed of a rubber tube having no rigidity, it alone grips a gripping object such as a wafer (hereinafter, referred to as a “work”). Then, deformation and vibration of the tube occur due to the weight of the work, and the required positional accuracy cannot be obtained. Further, this kind of bending actuator is constituted by a combination of a rubber tube and a reinforcing fiber. Therefore, if there is a shift in the position where the reinforcing fiber is stuck, the actual deformation behavior faithfully reflects this, which also lowers the position accuracy of the bending actuator.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and does not use a suction pad, which causes wafer contamination, but uses a flexible actuator to reduce the impact of a wafer approach. It is an object of the present invention to provide a plate-shaped member gripping device that can be eliminated and that can achieve high positional accuracy without a complicated control mechanism and that is suitable for application to the semiconductor manufacturing field.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a plate-like member gripping device according to the present invention comprises a rigid frame and two or more straight-moving members, one end of which is mounted on one side of the frame. Shape flexible actuator, a grip portion formed at the end of the straight-moving flexible actuator that is not fixed, a ventilation path interconnecting the straight-moving flexible actuators, and a pressure inlet formed in the ventilation path. Is provided. Further, the plate-shaped member gripping device of the present invention is the plate-shaped member gripping device, wherein the straight-moving flexible actuator includes a flexible tube, a fixed holder that holds one end of the tube, and the tube. , And a tube cap that slides in the axial direction with respect to the fixed holder.

The plate-like member gripping device of the present invention is the plate-like member gripping device, wherein the straight-moving flexible actuator comprises a flexible tube and a fixed holder for holding one end of the tube. And a tube cap that holds the other end of the tube and slides in the axial direction with respect to the fixed holder, and a reinforcing fiber joined around the tube. Further, in the plate-like member gripping device of the present invention, in the above-mentioned plate-like member gripping device, by introducing compressed air to the straight-type flexible actuator from the pressure introduction port via an air passage inside the frame, the linear-type flexible member is moved. The actuator is extended and retracted to grip the outer periphery of the plate-shaped member placed at the center of the frame.

[0011]

According to the plate-like member gripping device of the present invention having the above-described structure, when compressed air is introduced from the pressure introduction port, the air pressure is increased through the air passage formed in the frame to the inside of the tube of each straight-type flexible actuator. Is applied to For this reason, the volume inside the actuator increases, and accordingly, the tube cap moves in the axial direction of the fixed holder, and the linear flexible actuator expands. As a result, the gripping portion at the tip of the actuator moves toward the center of the frame, and is flexibly fitted to the peripheral edge of the plate member placed at the center of the frame. Thus, the plate member is gripped.

Here, since the plate-like member is gripped by the straight-type flexible actuators provided at two or more places of the rigid frame, vibration is not generated due to inertia of the plate-like member, and the grip is stable. I have. Further, the reinforcing fibers wound around the tube of the straight-type flexible actuator suppress expansion of the tube in the radial direction, thereby enabling highly efficient and stable movement of the straight-type flexible actuator. When the compressed air is released from the pressure inlet, the air pressure applied to the straight-type flexible actuator is released, and the flexible actuator returns from the expanded state to the original state. Accordingly, the grip of the wafer is released.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a plate-like member gripping device of the present invention is embodied for a silicon wafer will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of the plate-shaped member gripping device of the present embodiment. The plate-shaped member gripping device 1 shown in FIG. 1 has a rigid frame 2 formed in an annular shape as a skeleton, and flexible actuators 3 are attached to four inner peripheral portions of the frame 2 to form a pressure inlet 4. The gripping of the wafer 29 placed at the center of the frame 2 by the cooperation of the expansion and contraction of the four flexible actuators 3. Frame 2
In addition to the above, an attachment stay 30 is provided, and is attached to a transport mechanism (not shown) via the attachment stay 30.

First, the frame 2 will be described. The frame 2 forms a skeleton of the plate-shaped member holding device 1 and also serves as a pipe for introducing compressed air applied from the pressure inlet 4 to the four flexible actuators 3. The frame 2 in the plate-shaped member gripping device 1 is formed by forming a hollow pipe having a square cross section into a substantially square shape as shown in the figure. The frame 2 is required to have rigidity to withstand the weight of the silicon wafer to be gripped. Therefore, as a hollow pipe for forming the frame 2, a material such as aluminum or stainless steel having a necessary strength is used.

A total of four flexible actuators 3 are arranged on the inner peripheral side of each curved portion of the frame 2, and a pressure introduction port 4 is formed at one location. Communicate with each other through the hollow portion of the pipe. Since the joint portion 31 of the hollow pipe in the frame 2 must not cause pressure leakage, a gasket 33 is fitted inside as shown in FIG. 6, and this is tightened with a nut 32 and a washer 34 with a bolt 35,
Prevents pressure leaks.

Next, the flexible actuator 3 will be described with reference to FIG. The flexible actuator 3 utilizes the elasticity of a flexible tube made of rubber or the like to obtain flexible linear motion by applying compressed air to the inside. The flexible actuator 3 includes a rubber tube 5, a fixed holder 6, and a tube cap 7. The fixed holder 6 has a fitting portion 8 fitted to the frame 2, a tube holding groove 9 for holding one end of the rubber tube 5, and a cylindrical portion 10 for slidably holding the tube cap 7. . Further, a through hole 12 penetrating through the fitting portion 8 and a through hole 13 penetrating through the cylindrical portion 10 are formed. The fitting portion 8 is threaded.

The tube cap 7 has a piston portion 14 slidably held by the cylindrical portion 10 of the fixed holder 6, a tube holding groove 15 for holding the other end of the rubber tube 5,
A grip 16 is formed which engages with the periphery of the work (wafer 29) and grips the work. Tube cap 7
Can move in the axial direction, that is, in the left-right direction in FIG. 3A by sliding between the piston portion 14 and the cylindrical portion 10. Further, an inner chamber 17 is formed by the inside of the cylindrical portion 10 and the piston portion 14.

As shown in the external view (a) and the cross-sectional view (b) of FIG. 4, the rubber tube 5 has a non-stretchable reinforcing fiber 18 adhered to a stretchable tubular tube 23 in the circumferential direction. It was done. When compressed air is applied to the inside of the rubber tube 5, the tube 23 is elastically stretched to increase the volume. However, since the reinforcing fibers 18 are adhered in the circumferential direction, they cannot be expanded in the radial direction. The tube 23 extends only in the longitudinal direction. In the rubber tube 5, as the material of the tube 23, any material having appropriate flexibility and elasticity such as silicone rubber and raw rubber may be used. Reinforcing fiber 18
The material may be a metal fiber, a carbon fiber, a silk thread, or the like, but a material having good compatibility with the tube 23 and the adhesive, and having high flexibility only in the operation direction and low flexibility in the non-operation direction is used. Good to do. It is preferable to use an adhesive of the same quality as the tube 23 as an adhesive for joining them.

As shown in FIG. 3 (a), one end of the rubber tube 5 is hermetically fixed to the tube holding groove 9 of the fixed holder 6 and the other end is sealed to the tube holding groove 15 of the tube cap 7. Therefore, a peripheral chamber 19 is formed between the cylindrical portion 10 of the fixed holder 6 and the rubber tube 5. Perimeter 19
And the inner chamber 17 communicate with each other through the through hole 13.

Next, the frame 2 of the flexible actuator 3
A description will be given of the attachment to the device. As shown in FIG. 5, a mounting hole 20 is formed in the frame 2 at a position where the flexible actuator 3 is mounted, and a nut 21 is embedded in the mounting hole 20. The fitting portion 8 of the flexible actuator 3
Gasket 24 is fitted and nut 21 is passed through mounting hole 20.
, The flexible actuator 3 can be attached to the frame 2. At this time, the hollow part 22 of the frame 2 and the inner chamber 17 of the flexible actuator 3 communicate with each other through the through hole 12 of the fixed holder 6. Next, the pressure inlet 4 will be described. The pressure inlet 4 communicates the hollow portion 22 of the frame 2 with the outside. Pressure inlet 4
If a compressed air source and a pressure relief valve are connected to the end of
Compressed air can be applied to the inside of the frame 2 through the pressure inlet 4, or the applied compressed air can be released.
If the pressure inlet 4 is a so-called one-touch joint, it is practically convenient.

Next, the operation of the plate-like member gripping device 1 having the above configuration will be described. The plate-shaped member gripping device 1 includes:
A compressed air source and a pressure relief valve are connected to the pressure inlet 4 for use. The type of the compressed air source is not particularly limited, such as a compressed air cylinder or an air pump. The pressure relief valve may be anything as long as it can reliably open and close the air passage.

When the compressed air from the compressed air source is applied to the pressure inlet 4, the compressed air is introduced into the hollow portion 22 in the frame 2, and the pressure in the hollow portion 22 becomes high. When the pressure in the hollow part 22 rises, compressed air is introduced into the inner chamber 17 through the through hole 12 of the fitting part 8 of the fixed holder 6 in each flexible actuator 3, and further, through the through hole 13 of the cylindrical part 10. Compressed air is also introduced into the peripheral chamber 19. Thus, the pressure in the inner chamber 17 and the peripheral chamber 19 of each flexible actuator 3 increases,
The volumes of the inner chamber 17 and the peripheral chamber 19 are about to increase. Therefore, the rubber tube 5 extends in the axial direction, and the tube cap 7 slides and moves rightward in FIG. 3A. At this time, since the movement of the tube cap 7 is performed while resisting the elastic force of the rubber tube 5 by the pressure of the compressed air, the movement is flexible.

Here, since the reinforcing fibers 18 are attached in the circumferential direction of the rubber tube 5, the rubber tube 5 is prevented from expanding in the radial direction. Reinforcing fiber 1
Although it is possible to use even when there is no reinforcing fiber 8, a part of the volume increase of the inner chamber 17 and the peripheral chamber 19 is consumed in expanding the rubber tube 5 in the radial direction. It requires extra high air pressure. Further, the burden on the tube is large, and the life is shortened. Therefore, the reinforcing fiber 1
8 is more efficient because the supply air pressure can be used more efficiently and the life of the tube is longer.

When each flexible actuator 3 is extended, the holding portion 16 formed on the tube cap 7 engages with the peripheral edge of the wafer 29 (see FIG. 3B), and the wafer 29 is held by the plate-like member holding device 1. Is grasped. This state is shown in FIG.
Shown in Note that the movement when the flexible actuator 3 is engaged with the wafer 29 is a flexible movement as described above.
No impact is applied to the wafer 29. That is, the wafer approach can be performed without mechanical shock. In addition, wafer 2
Even if the position of 9 is slightly shifted and one of the four flexible actuators 3 is engaged with the wafer 29 earlier than the other, the wafer 29 naturally moves by the cooperation of the four flexible actuators 3. Is corrected to the correct position and gripped.

With the wafer 29 shown in FIG. 2 held,
The plate-shaped member holding device 1 is transported to a wafer receiving unit of another semiconductor manufacturing device. Even during the movement, each flexible actuator 3 has its base end fixed to the rigid frame 2, so that the vibration due to the inertia of the wafer 29 can be minimized. When the air pressure is released by opening the pressure release valve at the destination, each flexible actuator 3 returns from the extended state to the original state (see FIG. 3A).
The wafer 29 is no longer held, and is accepted by the semiconductor manufacturing apparatus. Then, the plate-like member gripping device 1 is transported again to the original place to move the next wafer.

From the above description, in the plate-like member gripping device 1 of the present embodiment, the flexible actuator 3 showing a soft movement by applying air pressure and releasing pressure is attached to the rigid frame 2 so that no impact is caused. No unnecessary vibration is involved even when the wafer is approached and the wafer is being gripped. In addition, precise position control, speed control, and the like are not required, and supply of normally used compressed air is sufficient. As a result, an excellent plate-like member gripping device that can be applied to wafer transfer in a semiconductor manufacturing apparatus that does not like impact is realized.

The above embodiment does not limit the present invention, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, in the above embodiment, the number of flexible actuators used is 4
Although three pieces are sufficient, three pieces are sufficient to hold the work, and two pieces may be used in the case of a relatively lightweight work such as a 4-inch wafer. Further, the pipe used as the frame has a square cross section, but may have another cross section as long as the mounting position accuracy of the flexible actuator can be ensured. Further, although the pipe is used as the frame and the internal space of the pipe is used as the pipe to the flexible actuator, the pipe may be provided separately from the frame. Further, the frame and the pipe do not need to form a complete ring, and any shape may be used as long as a gripping position and rigidity for stably gripping the work can be secured and compressed air can be reliably supplied to each flexible actuator. Further, the present invention may be applied to fields other than the semiconductor manufacturing apparatus.

[0028]

As is apparent from the above description, in the plate-like-member gripping device of the present invention, two or more linearly-movable flexible actuators are provided on one side of a rigid frame and communicate with each other. Since the workpiece is gripped by the grip portion formed at the tip of each straight-type flexible actuator, no impact is applied to the workpiece even during approach, and unnecessary vibration does not occur due to the weight of the workpiece. . In addition, it can be driven by commonly used compressed air and does not require a complicated control mechanism. In addition, since the reinforcing fibers are bonded to the periphery of the rubber tube of the straight-moving type flexible actuator, there is no wasteful expansion in the radial direction of the tube, and the efficiency is excellent.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a plate-shaped member gripping device according to the present invention.

FIG. 2 is a diagram illustrating a state where a wafer is gripped by a plate-shaped member gripping device according to the present invention.

FIG. 3 is a cross-sectional view of a rectilinear flexible actuator used in the plate-like member gripping device shown in FIG.

FIG. 4 is a view showing a rubber tube to which reinforcing fibers are bonded.

FIG. 5 is a diagram showing attachment of a straight-type flexible actuator to a plate-like member gripping device.

FIG. 6 is a view showing a seal at a joint portion of a frame of the plate-like member gripping device.

FIG. 7 is an explanatory diagram showing an example of a flexible actuator according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plate-shaped member holding device 2 Frame 3 Flexible actuator 4 Pressure introduction port 5 Rubber tube 6 Fixed holder 7 Tube cap 16 Holding part 18 Reinforcing fiber

Claims (2)

(57) [Claims] 1. A rigid frame; two or more straight-type flexible actuators each having one end mounted on a row of side surfaces of the frame; and a grip formed at a fixed end of the straight-type flexible actuator. When the air passage which communicates the respective linear shaped flexible actuator together, and has a its ventilation channel formed in the pressure inlet, the linear-shaped flexible actuator, a tube with a flexible, one end of the tube And a rigid guide is fixed
A fixing holder which is, holds the other end of the tube, the guide
Along possess a tube cap to slide axially, said tube, said guide and said switch and said fixed holder
A plate-like member gripping device, which covers the entire sliding portion of a tube cap . 2. The plate-like member gripping device according to claim 1, wherein the straight-moving flexible actuator has reinforcing fibers joined around a flexible tube. .