JPH11347978A - Gripping method and device and object handling device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To nullify the loss time of direction sensing and restriction of a circular object using a small and inexpensive device. SOLUTION: When a circular object 1 is gripped by pawls laid in line facing in a certain direction on a circumference by allowing the first group A consisting of the first to third pawls 11-13 to separate from and contact with the second group B consisting of the fourth 14 and fifth pawls 15, the first to third pawls 11-13 are abutted to three points any in the range below 180 deg. of circumference of the circular object 1, and the fourth pawl 14 is abutted to any one point F at which the second pawl 12 and the first 11 adjacent thereto are positioned opposing on the diameteric line X1-X1 of the object 1 in the range Y1 between two positions C and D where the pawls 12 and 11 abut to the object 1, while the fifth pawl 15 is abutted to any one point at which the second pawl 12 and the third pawl 13 on the other side adjacent thereto 12 are positioned opposing on the diameteric line X2-X2 of the object 1 in the range Y2 between two positions D and E where the pawl 12 and 13 abut to the object 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for gripping a circular object and an article handling apparatus using the same.

[0002]

2. Description of the Related Art For example, a semiconductor wafer is a disk-shaped component, and a reaction chamber is used to form an electrode pattern or the like on the surface of the semiconductor wafer by plasma dry etching. In this process, the wafer is held in the reaction chamber by electrostatically adsorbing it on the electrode, the plasma is generated by evacuating the reaction chamber, and the heat transfer gas is applied to the back surface of the wafer facing the electrode. Fine and high-precision processing is performed, for example, by supplying a certain He gas to maintain the temperature.

In order to achieve such processing with the required accuracy, it is necessary to mount a wafer on the electrode with high positional accuracy. Wafers are often disk-shaped,
The position of the center becomes a problem. Therefore, as shown in FIGS. 2 and 3, three claws g to h as shown in FIG. Six jaws j to o as shown in FIG.
Centering and holding the wafer, and sequentially transferring the wafer as the process progresses. Accordingly, when the article handling hand f having the fingers d and e handles the wafer a variously, the center position thereof is uniquely determined between the article handling hand f and the article handling hand f, and the article can be handled with high positional accuracy. This is convenient for handling the wafer a in fine and high-precision processing.

[0004] Incidentally, the wafer a is a single crystal,
An electrode pattern or the like must be formed corresponding to the direction of the crystal. Accordingly, a notch b, an orientation flat, or a notch as shown in FIGS. 2 and 3 is provided at one place on the outer periphery to indicate the direction of such a crystal of the wafer. Wafer a is replaced with nail g in FIG.
~ I, to be gripped from both sides by claws j ~ o in FIG.
One of them may be located at a position facing the notch b or the like, and a play can be made between the claw at this position and the wafer a.

To cope with this, in the case shown in FIG.
The notch b is detected by rotating the wafer a by the sensor c, and the detected notch b is regulated so as to be gripped by the claws g to i in a direction not facing any of the claws g to i. .

In the case shown in FIG. 3, each finger d and e is provided with three claws j to l and claws m to o, and a notch b or the like is opposed to any of these claws to cause play. Even so, the remaining five wafers can be centered and gripped without play.

[0007]

However, the gripping method shown in FIG. 2 requires a detecting device for detecting the notch b of the wafer a in advance, so that the equipment costs are high, and the detection and the orientation control based on this detection are required. Work efficiency does not increase because of loss time. Therefore, it causes a rise in product cost.
In the method shown in FIG. 3, the number of claws is six, which increases the cost and increases the load on the tip of the component handling hand f. Therefore, the positional accuracy required for gripping and handling the wafer a due to the influence of inertia and the like. Is difficult to secure. In order to ensure sufficient positional accuracy, it is necessary to increase the support rigidity of the article handling hand f and to increase the driving force and the rigidity of position control by that amount, so that the device becomes large and expensive, which also increases the cost. Cause.

An object of the present invention is to provide a small and inexpensive device,
In addition, it is an object of the present invention to provide a method and apparatus for gripping a circular object and a product handling apparatus using the same, which can eliminate loss time for detecting the orientation of the circular object and eliminating the time required for the orientation.

[0009]

In order to achieve the above object, a gripping method according to the present invention is applicable to a circular object having a notch, an orientation flat, or a notch at one place on the circumference. , The first in the circumferential direction
Of the five to fifth claws, the first to third claws constitute a first group of claws, and the fourth and fifth claws constitute a second group of claws, and are separated from and brought into contact with each other. The first group of claws is brought into contact with any three points within a range of 180 ° or less of the circumference of the circular object by the first to third three claws to grip the fourth group of the second group of claws. The nails
In a range between both positions where the second claw at the center of the first claw group and the first claw adjacent to the second claw abut on the circular object,
Abut on any one point facing each other on the diameter line of the circular object,
The fifth nail of the second group of nails is located at the center of the first group of nails.
The circular object is brought into contact with an arbitrary point on the diameter line of the circular object in a range between both positions where the claw and the third nail on the other side adjacent to this come into contact with the circular object. One feature is that it is centered and gripped.

In this case, even if one of the five first to fifth claws faces the notch of the circular object and can play with the circular object, the remaining four claws are circular. By contacting four points adjacent to each other within a range of less than 180 ° on the outer periphery of the circular object, the distance between any adjacent contact positions is one of the outer periphery of the circular object.
The angle of the circular object is not more than 80 °, and therefore, the area between adjacent contact positions is equal to or more than 180 ° of the outer phase of the circular object so that the circular object does not fall out or play. Since the centering and gripping can be performed by restricting in the direction, it is not necessary to detect the direction of the circular object in advance and regulate the gripping direction, and it is possible to omit a device and a time therefor. Also, since only five claws are required, the number of parts and the weight are reduced as compared with the conventional case of six claws, so that the support rigidity, the control rigidity of the position and the driving force required for a device for handling a circular object are also reduced. In addition, the size and cost of the device can be reduced. If the first to third three claws of the first claw group are arranged beyond the outer circumference 180 ° of the circular object, the three nails cannot be brought into contact with the circular object from the side. The object cannot be gripped by centering between the claws of the first and second claws.

The fourth to fifth claws of the first to third three second claw groups of the first claw group are respectively provided on a pair of fingers which are separated from each other. By using the gripping device, the circular object can be gripped as described above by one operation of opening and closing the pair of fingers, or the grip can be released. By using the gripping device as an article handling device that grips a circular object to carry and handle variously, the circular object can be handled with high positional accuracy and used for various operations, or various operations can be performed.

Further objects and features of the present invention will become apparent from the following detailed description and drawings. Each of the above features of the present invention can be used alone or in combination in various combinations as much as possible.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to FIGS.

The method and apparatus for gripping a circular object according to the present embodiment uses a semiconductor wafer 1 as a target for gripping a circular object as shown in FIG.
This is an example of a case where the article is handled in various ways such as being transferred by the article handling apparatus 21 of FIG. However, the present invention is not limited to this, and can be applied to any application or device that grips and handles a circular object, and may use a notch 1a, an orientation flat, a notch, etc. The present invention is equally applicable to any circular object having one place on the outer periphery.

The gripping method according to the present embodiment will be described with reference to an article handling device 21 shown in FIG. In order to center and hold the wafer 1 between the first and second claw groups A and B on both sides to be separated from each other, the wafer 1 has a fixed circumferential direction corresponding to the wafer 1, that is, a clockwise direction in this embodiment. The first to fifth five claws 11 to 15 arranged in the direction are used.

The first nail group A includes first to third three nails 11.
In steps 13 to 13, the wafer 1 is brought into contact with three points C, D, and E in an angle θ1 range of 180 ° or less. Correspondingly, the fourth claw 14 of the second claw group B is located at the center of the first claw group A.
The diameter line X1 of the wafer 1 is located in a range between both positions C and D where the first claw 12 and the first first claw 11 adjacent thereto come into contact with the wafer 1, that is, an inner range Y1 of both positions C and D. -X1
The fifth claw 15 of the second claw group B is brought into contact with an arbitrary point F opposed to the upper claw.
The diameter line X2 of the wafer 1 is located in a range between the two positions D and E where the second claw 12 and the third claw 13 on the other side adjacent to the same abut on the wafer 1, that is, an inner range Y2 between the two positions D and E. -X2
The wafer 1 is centered and gripped by being brought into contact with an arbitrary point facing the upper side or the like. as a result,
The angle range θ2 of the outer circumference of the wafer 1 between the contact positions F and G where the fourth and fifth two claws 14 and 15 of the second group of claws B are in contact is θ2 <θ1. Become a relationship. However, this is not a sufficient condition.

The contact points C to G of the first to fifth five claws 11 to 15 holding the wafer 1 with respect to the wafer 1 are set between adjacent contact points, that is, between C and D, and between D and E. , Between E and F, between F and G, and between G and C, the angular range of the outer periphery of the wafer 1, in other words, the angular range around the center point P of the wafer 1 is opened by 180 ° or more. In such a case, the wafer 1 cannot be restrained in that direction, and may fall out of the centering position or cause play. That is, centering cannot be performed without dropping. In FIG. 1, the first to third members of the first nail group A are temporarily
The center second nail 12 of the three nails 11 to 13 is
Like the nail 12 'shown by a virtual line in FIG. 1, the fifth nail 15 of the second nail group B and the diameter line X1-X1 of the wafer 1 are located, and the notch 1a of the wafer 1 If the third claw 13 of the third claw group A is opposed to the third claw group A, a play S is made between the third claw 13 and the wafer 1.

As a result, the abutting positions D 'and F of the wafer 1 by the claws 12' and 15 become adjacent abutting positions, and the angle range on the outer periphery of the wafer 1 becomes 180 °. Therefore, it is impossible to prevent the wafer 1 from falling in the direction of the arrow H or causing play. As the position of the nail 12 ′ further approaches the side of the nail 11, the grip of the wafer 1 becomes less sweet.

However, when gripping as described above,
The notch 1a of the wafer 1 is opposed to one of the fifth five claws 11 to 15, for example, the third claw 13 as described above, and a play is provided between the third claw 13 and the wafer 1. Even if S is made, the remaining first, second, fourth, and fifth four claws 11,
A position C at which 12, 14, 15 contact the outer periphery of the wafer 1;
Since the angular range of the outer circumference of the wafer 1 adjacent to D, G, and F is less than 180 °, the wafer 1 can be restrained in any direction, centered and gripped. Such a gripping condition of the wafer 1 is determined by the notch 1a of the wafer 1.
Is satisfied when any one of the first to fifth five claws 11 to 15 faces.

When the wafer 1 is gripped in this way, it is not necessary to detect the direction of the wafer 1 in advance and regulate the direction in which the wafer 1 is gripped. In addition, the number of necessary claws may be the first to fifth five claws 11 to 15, so that the number of parts and the weight are reduced as compared with the case of six conventional claws. Since the supporting rigidity, position control rigidity, and driving force are also reduced, the size and cost of the apparatus can be reduced. Therefore, the product cost is also reduced. When the first to third three claws 11 to 13 of the first claw group A are arranged beyond the outer periphery 180 ° of the wafer 1, the first to third three claws 11 to 11 are attached to the wafer 1. Since the wafer 13 cannot be abutted from the side, the wafer 1 cannot be centered and gripped by the nail groups A and B on both sides.

In this embodiment, these first nail groups A
First to third three nails 11 to 13 and third nail group B
The fourth and fifth two claws 14 and 15 are applied as a gripping device 34 that is planted as a pin-shaped member on each of a pair of fingers 31 and 32 that are separated from and attached to each other,
A single operation of opening and closing the pair of fingers 31 and 32 of the gripping device 34 can grip a circular object as described above or release the grip. However, the first to fifth
The five claws 11 to 15 are not limited to pin-shaped claws, but may be any as long as they can grip a circular object such as the wafer 1 by opening and closing the fingers 31 and 32 and release the grip. The opening and closing of the pair of fingers 31 and 32 can be performed by a manual mechanism. However, when the pair of fingers 31 and 32 are automatically performed by using a suitable driving mechanism 30 or a driving device, the component handling device 21 grips the wafer 1 by the gripping device 34 and carries the wafer 1. This is suitable for automatically performing handling operations according to a predetermined program.
The fingers 31 and 32 are moved in parallel by the drive mechanism 30 so as to be opened and closed. However, if a finger such as the wafer 1 can be gripped and the grip can be released, the fingers 31 and 32 may be opened and closed by turning, or a combined movement. It can be opened and closed by

The article handling apparatus 21 according to the present embodiment
A gripping device 34 is attached to the end of the robot arm 22 that expands, contracts, undulates, and rotates with a horizontal maintenance function, and is used to sequentially transfer the wafer 1 as the processing process of the wafer 1 progresses.

[0023]

According to the gripping method of the present invention, a circular object having a notch, an orientation flat, or a notch in one place can be centered and gripped between claws on both sides that come and go. Since it is not necessary to detect the direction of the circular object in advance and regulate the direction in which the object is gripped, it is possible to omit a device and a time therefor. In addition, since only five claws are required for gripping a circular object, the number of parts and weight are reduced as compared with the conventional case of six jaws, thereby controlling the support rigidity and position required for a device for handling a circular object. Since the rigidity and the driving force are also reduced, the size and cost of the device can be reduced. As a result, the product cost is also reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing a gripping method and apparatus according to an embodiment of the present invention, and an article handling apparatus using the same.

FIG. 2 is a plan view showing one conventional gripping method and device.

FIG. 3 is a plan view showing another conventional gripping method and device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wafer 1a Notch 11-15 Claw 21 Article handling device 31, 32 Finger 34 Grasping device A One side nail group B The other side nail group C-G Contact point X1-X1, X2-X2 Diameter line Y1, Y2 Between contact positions Range θ1 Range of 180 ° or less of wafer 1

Claims (3)

[Claims] 1. A first claw of a first to fifth claws arranged in a fixed circumferential direction corresponding to a circular object having a notch, an orientation flat, or a notch at one place on the circumference. The third nail is a first nail group, and the fourth and fifth nails are a second nail group. The first and second nail groups are separated from each other and grip a circular object therebetween. The circumference 18 of a circular object with the first to third three claws
The third nail is brought into contact with any three points within a range of 0 ° or less, and the fourth nail of the second nail group is connected to the second nail at the center of the first nail group and the first nail on one side adjacent thereto. The second claw group is brought into contact with an arbitrary point on the diameter line of the circular object in a range between both positions where the second claw contacts the circular object. The second claw at the center of the circle and the third claw on the other side adjacent to the second claw are brought into contact with an arbitrary point facing each other on the diameter line of the circular object in a range between both positions where the second nail contacts the circular object. A gripping method characterized by centering and gripping a circular object. 2. A pair of fingers which are separated from and separated from each other, and one of the fingers is arranged in a certain direction in a circumferential direction of the circular object which comes into contact with any three points within a range of 180 ° or less in circumference of the circular object. The first to third claws are provided to form a first claw group, and the other finger includes a second claw at the center of the first claw group and a first claw adjacent to the second claw. A fourth claw contacting an arbitrary point facing each other on the diameter line of the circular object, a second claw at the center of the first group of claws, and a second claw in the range between the two positions abutting the circular object; A second claw group provided with a fifth claw that abuts at an arbitrary point that opposes on the diameter line of the circular object in a range between both positions where the third claw on the other side abuts on the circular object; A gripping device, characterized in that: 3. An article handling apparatus for gripping and carrying various kinds of circular objects by a gripping device having a pair of fingers which are separated from and separated from each other, wherein said one finger is provided with a circular object having a circumference of 180 ° or less. The first to third claws are arranged in a circumferential direction of a circular object abutting three arbitrary points to form a first claw group, and the other finger is located at the center of the first claw group. A fourth claw abutting at any one of the positions where the second claw and the first claw adjacent thereto abut on the circular object between two positions abutting the circular object on a diameter line of the circular object; The second claw located at the center of the first claw group and the third claw adjacent to the second claw are opposed to each other on the diameter line of the circular object in a range between both positions where the second nail contacts the circular object. An article handling apparatus, comprising: a fifth group of nails provided with a fifth nail that abuts on one point.