JP2010199245A - Wafer conveyance system equipped with prealigner device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer conveyance system equipped with a prealigner device composed of taking no time in an assembling and adjustment, and capable of substantially reducing the time required for the delivery and receipt of the wafer to and from a wafer conveyance device. <P>SOLUTION: The prealigner device holds to rotate the wafer, detects an outer circumference of the wafer with a sensor, and rotates the wafer to at least desired direction with the use of the information detected by the sensor. The prealigner device includes: an absorption surface 12 contacting to the rear surface of the wafer to absorption-hold it formed to a gripping member 1 for holding the wafer; and a concave part 14 into which an end effector 13 of the wafer conveyance device for conveying the wafer to the absorption surface 12 can go. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wafer transfer system that is used in a semiconductor manufacturing apparatus or an inspection apparatus, and includes a pre-aligner apparatus that performs angle alignment such as wafer centering and notch, and a wafer transfer apparatus that transfers a wafer to the pre-aligner apparatus. Is.

The pre-aligner apparatus is an apparatus for positioning a wafer in a turning direction and aligning a wafer center in a wafer transfer path in a semiconductor manufacturing apparatus or an inspection apparatus, and is often used as a wafer transfer system in combination with the wafer transfer apparatus. . The wafer transfer device performs wafer alignment to a desired position after aligning the wafer with the pre-aligner device.
When a wafer is placed on the pre-aligner device from the wafer transfer device, the wafer is first gripped. The pre-aligner device grips the wafer by forming a vacuum path in the gripping member and gripping the backside of the wafer by vacuum suction, or by applying a voltage to the gripping member and attracting the wafer by electrostatic force. There is a method in which the gripping member itself moves and the gripping member moves toward the center of the wafer to sandwich and grip the outer periphery of the wafer. In addition to these, there is also a gripping method based on the wafer's own weight, the friction coefficient of the back surface of the wafer, and the frictional force of the elastic body using an embedded support stand such as an elastic body that contacts the back surface of the wafer.
The pre-aligner apparatus grips the wafer by any of these methods and rotates the wafer once. A notch called a notch indicating the crystal direction of the wafer is provided on the outer periphery of the wafer, and a notch portion is detected by a notch detection sensor provided in the pre-aligner device. Then, positioning is performed so that the notch of the wafer is directed in a predetermined direction.
Some pre-aligner devices not only perform notch alignment but also detect and calculate the center deviation of the wafer based on information obtained by the notch detection sensor, and perform center alignment. As a method of centering the wafer, the gripping member can be arbitrarily moved in the plane direction so that the wafer is positioned at the center with respect to the wafer transfer position of the wafer transfer device after calculating the center deviation amount. When the wafer transfer device shifts (corrects) the wafer receiving position with respect to the rotation center of the pre-aligner device based on the method of moving the gripping member or the information on the wafer center deviation amount, and receives the wafer. There is a method of moving the end effector of the transport device so that the center position thereof matches. In addition, in the method in which the gripping part grips and holds the outer periphery of the wafer, the center position of the wafer is often mechanically corrected to a desired position when gripped. In this case, the notch detection sensor detects only the position of the notch portion and only positions the notch to a predetermined position. As an example of the pre-aligner device in this case, there is Patent Document 1 or the like.

By the way, the outer dimensions of a wafer as a substrate of a semiconductor element have been gradually increased in recent years from the viewpoint of manufacturing cost and productivity improvement, and specifically, the outer diameter of the wafer has shifted from 300 mm to 450 mm. Yes. However, although the diameter has been increased, the thickness dimension of the wafer has not been increased so much, and the ratio of the diameter to the wafer thickness has become rather small. In addition, although there is no direct relationship with the increase in diameter, there is a wafer in which the thickness of the wafer is extremely thinned by cutting or the like depending on the contents of the semiconductor manufacturing process.
Such a large-diameter wafer or thin wafer is bent only by its own weight so that the central portion of the wafer hangs down in the cassette because only the end face of the wafer is supported in the cassette for housing the wafer. In this state, the end effector (the part that grips the wafer) of the wafer transfer device sucks the central portion of the back surface of the wafer so that the wafer transfer device can securely put in and out the cassette without damaging the wafer. Yes. In this case, the shape of the end effector is a paddle-like substantially rectangular thin plate. Also, in the pre-aligner device, it is more effective to hold the central portion of the wafer over a relatively wide range against the deflection of the wafer, so the wafer back surface area is almost the same as the end effector of the wafer transfer device. There is a need to.
Then, it is necessary to avoid mechanical interference between the end effector of the wafer conveyance device and the holding member of the pre-aligner device. Therefore, in order to avoid this interference, the pre-aligner apparatus needs a lifter mechanism for raising and lowering the wafer.
In addition, even in the case of a pre-aligner device that does not hold by suction as described above and grips the outer periphery of the wafer, it avoids mechanical interference between the grip portion that grips the wafer and the end effector during wafer transfer. Has a lifter mechanism. This is because the notch of the wafer is placed at an arbitrary position with respect to the pre-aligner apparatus, and therefore, the grip portion for gripping the wafer after the notch alignment becomes an indeterminate position with respect to the end effector. Therefore, a lifter mechanism is required to move the grip portion to a predetermined position after lifting the wafer once from the grip portion. Alternatively, a lifter mechanism is necessary for the grip portion of the pre-aligner device and the end effector of the wafer transfer device to raise the wafer to a region where there is no mechanical interference. In this type of pre-aligner device that grips the outer periphery, the grip portion becomes an indeterminate position after the notch is adjusted to a predetermined position as described above, so there is a possibility of mechanical interference between the grip portion and the lifter portion. There are various ideas for avoiding interference. In particular, Patent Document 1 has been devised to compensate for the drawbacks.

JP 2002-151577 A

As described above, in the wafer delivery between the pre-aligner device and the wafer transfer device, when the pre-aligner device has a lifter mechanism, especially when the wafer is delivered at the lifted position of the lifter mechanism, the notch positioning on the gripping part, Since it is necessary to transfer the wafer center-aligned wafer to the wafer transfer device while maintaining the positional accuracy on the gripper from the viewpoint of ensuring alignment accuracy, the gripping member pivot center and lifter mechanism lift These mechanical alignments are required so that the wafer center position at the position matches. That is, it is necessary to ensure the straightness in the lift operation stroke of the lifter mechanism with high accuracy.
On the other hand, in wafer transfer between the pre-aligner device and the wafer transfer device, the wafer transfer device needs to insert the end effector between the upper surface of the grip portion of the pre-aligner device and the lower surface of the wafer when the lifter mechanism is in the raised position. Therefore, the lift stroke of the lifter mechanism requires a long stroke considering the thickness of the end effector.

Therefore, the lifter mechanism requires expensive parts such as a direct-acting precision guide, which has a drawback that the structure becomes complicated and the number of parts increases, resulting in an increase in cost. In addition, there is a problem that it takes time to assemble and adjust the pre-aligner device in order to ensure straightness of the lifter mechanism.
Furthermore, the pre-aligner device must limit the lifting speed so as not to shift the wafer position when the wafer whose notch alignment is completed is transferred from the gripper to the lifter or when it reaches and stops at the lifter lift position. Therefore, if the lifter lift stroke is long, the lift operation takes time.
In view of such a situation, the present invention provides a pre-aligner apparatus that reduces costs and does not require time for assembly adjustment, and provides a wafer transfer system using a pre-aligner apparatus that significantly shortens the wafer transfer time with the wafer transfer apparatus. Objective.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a pre-aligner device that holds and rotates a wafer, detects an outer periphery of the wafer by a sensor, and rotates at least the wafer in a desired direction using detection information of the sensor. The holding member that holds the wafer is formed with a suction surface that contacts and holds the back surface of the wafer, and a recess into which an end effector of a wafer transfer device that transfers the wafer to the suction surface can enter. This is a pre-aligner device characterized by that.
The invention according to claim 2 is the pre-aligner according to claim 1, wherein the recess has a shape having a step larger than the thickness of the end effector and a width larger than the width of the end effector. It is a device.
The invention according to claim 3 is the pre-aligner apparatus according to claim 1, wherein the end effector is formed in a paddle shape and sucks the back surface of the wafer to convey the wafer. It is.
According to a fourth aspect of the present invention, when the wafer is supported around the gripping member, the wafer can be raised to a position where the back surface of the wafer is higher than the upper surface of the suction surface, and the wafer is in the suction surface. 2. A pre-aligner apparatus according to claim 1, further comprising a lifter that can be lowered to a position lower than the back surface of the wafer when held by the wafer.
The invention according to claim 5 is the pre-aligner device according to claim 1, wherein the concave portion is formed at two or more locations on the gripping member.
According to a sixth aspect of the present invention, there is provided a wafer conveyance system comprising the pre-aligner apparatus according to the first aspect and a wafer conveyance device having the end effector.
According to a seventh aspect of the present invention, there is provided a semiconductor manufacturing apparatus comprising the wafer transfer system according to the sixth aspect.
According to an eighth aspect of the present invention, there is provided a semiconductor inspection apparatus including the wafer transfer system according to the sixth aspect.
According to a ninth aspect of the present invention, there is provided a gripping member having a suction surface for sucking a wafer and having a concave portion larger than an end effector of a wafer transfer device capable of transferring the wafer on the suction surface, and supporting the wafer A lifter that can be raised to a position where the back surface of the wafer is higher than the upper surface of the suction surface and can be lowered to a position lower than the back surface of the wafer when the wafer is held on the suction surface; A pre-aligner device comprising: a turning mechanism for rotating the gripping member; and a sensor for detecting an outer periphery of the wafer gripped by the gripping member, and rotating at least the wafer in a desired direction using detection information of the sensor. In which the wafer is placed on the suction surface by the end effector entering the recess. The wafer is sucked by the suction surface, the gripping member that sucks the wafer is rotated, the outer periphery of the wafer is detected by the sensor while performing the rotation, and the information on the outer periphery of the wafer from the sensor is obtained. Originally, the wafer is rotated in a desired direction, the suction surface releases the suction of the wafer, the lifter supports the wafer higher than the suction surface, and the recess is in the entry direction of the end effector. Rotating the grip portion so as to face, the lifter places the wafer on the suction surface, and the end effector enters the recess to remove the wafer. It is.
A tenth aspect of the present invention is the wafer alignment method according to the ninth aspect, wherein the suction surface is between the lifter placing the wafer on the previous suction surface and the end effector removing the wafer. Is a wafer alignment method characterized by adsorbing the wafer again.

According to the present invention, since the wafer transfer with the wafer transfer device can be performed not on the lifter but in the concave portion of the gripping portion, the lifter can have a very short lifting stroke. In other words, it is substantially unnecessary to mechanically match the center position of the wafer at the lifter lift position and the swivel center position of the gripper, and it is relatively simple with parts such as an electromagnetic solenoid actuator. Therefore, it is possible to provide a pre-aligner apparatus that is inexpensive and does not require assembly adjustment time.
Moreover, since the raising / lowering stroke is very small, the pre-aligner apparatus which does not require time for operation | movement can be provided.
Furthermore, it is possible to provide a low-cost wafer transport system that can shorten the operation time, and includes a pre-aligner device and a wafer transport device according to the present invention.

Side sectional view of the pre-aligner device of the present invention The top view which shows the pre-aligner apparatus of this invention, and the end effector of a wafer conveyance apparatus Side sectional view showing a state where the lifter is raised in the pre-aligner device of the present invention The top view which shows the other Example of the pre-aligner apparatus of this invention The perspective view which shows only the holding part of the Example of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The configuration of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of a pre-aligner apparatus according to the present invention, and FIG. 2 is a top view including a top view thereof and an end effector of a wafer transfer apparatus.
Reference numeral 1 denotes a gripping portion of the pre-aligner device, which is rotatable with respect to the turning portion base 8 by 5 bearings together with 2 rotating shafts, 3 rotating bases, and 4 A pulleys. These are connected to 6 B pulleys and 7 AC servo motors via a timing belt applied to the A pulley 4, and can turn in a state where the rotational position can be detected. Further, the swivel base 8 that holds the fixed side of the bearing 5 is provided with a hollow hole and connected to a rotary joint 9, and flows to the gripping part 1 through the hollow holes of the rotary base 3 and the rotary shaft 2. The road is in communication. The rotary joint 9 is connected to a solenoid valve described later. Further, the swivel unit base 8 is connected to the XY table 10 so as to be movable in the plane direction.

The grip portion 1 is provided with two wafer suction portions 12 having a planar portion, and these heights are formed to be the same. Moreover, it is formed so that it may be depressed in the height direction between these. For convenience of explanation, this recess is referred to as a recess 14. The flow path reaches the wafer suction unit 12, and a solenoid valve (not shown) connected to the rotary joint 9 switches between connection to a vacuum source and release to the atmosphere. Can be adsorbed and fixed, and adsorbed and released by air inflow.
Further, the concave portion 14 will be described. The concave portion 14 is formed to have a width slightly larger than the width of the paddle-shaped end effector 13 of the wafer transfer apparatus as shown in FIG. In addition, the height of the recess 14 between the lower surface of the wafer and the bottom surface of the recess 14 when the wafer suction unit 12 holds the wafer is at least larger than the thickness t of the end effector 13 of the wafer transfer device. It is formed as follows.
That is, by forming the concave portion 14, the paddle-shaped end effector 13 of the wafer transfer device does not contact the lower surface of the wafer attracted by the wafer attracting unit 12 or the lower surface of the wafer supported by the lifter 15 described later. What is necessary is just to be able to enter between the adsorption parts 12.

  Three lifters 15 for raising and lowering the wafer are provided on the outer periphery of the wafer gripping portion 1. The lifter 15 may be anything that can support the wafer, but it should not prevent at least the end effector 13 of the wafer transfer apparatus from entering. The descending position of the uppermost end of the lifter 15 is about 1 mm below the surface of the wafer adsorbing part 12 of the gripper 1, while the ascending position of the upper end of the lifter 15 is as shown in FIG. The lift stroke of the lifter 15 is much shorter than that of the prior art. Since the lift stroke required for the lifter 15 is short, the straight movement of the lifter 15 does not cause a problem. In the embodiment, each lifter 15 is fixed to the lifter base 17 and the push-pull type solenoid 16 is fixed to the lifter base. The lifter stopper 18 is only provided so as to be in contact with the lifter base 17 at the lowered position of the lifter 15. That is, unlike the prior art, a precise linear guide for maintaining the straightness of the lifter 15 is not required. When the push-pull solenoid 16 is not excited, the lifter 15 is in the lowered position, and the lifter is raised by energizing the push-pull solenoid 16.

  Reference numeral 11 denotes a notch detection sensor which detects the outer peripheral portion of the wafer. In this embodiment, the controller of the pre-aligner device (not shown) calculates the center position (center deviation amount) of the wafer together with the notch position based on the information of the notch detection sensor 11 and the rotational position information from the encoder of the servo motor 7. The controller of the pre-aligner apparatus may be integrated with the controller of the wafer transfer apparatus.

Next, operations of the pre-aligner apparatus and the wafer transfer apparatus configured as described above will be described.
When the end effector 13 of the wafer transfer device is to place a wafer on the pre-aligner device, the position of the grip portion 1 is controlled by the servo motor 7 so that the concave portion 14 faces the entry side of the end effector 13.
When the end effector 13 of the wafer transfer device enters the concave portion 14 and places the wafer on the wafer suction unit 12, the flow path is brought into a vacuum state by a solenoid (not shown), and the wafer is sucked and fixed to the wafer suction unit 12, and the wafer The transport device retracts the end effector 13.
Next, while the gripping part 1 is rotated once by the servo motor 7, the notch detection sensor 11 acquires the wafer outer periphery information, and from the rotation position information from the encoder of the servo motor 7 and the wafer outer periphery information, the controller Calculate the position and center position. Based on the calculation result, the gripper 1 is further rotated by the servo motor 7 to adjust the notch position to a predetermined position. At the same time as aligning the notch position, the gripper 1 is moved by the XY table 10 so that the end effector 13 can grip the wafer at a desired position, and the wafer is centered.
Thereafter, the wafer suction unit 12 releases the wafer, and the lifter 15 is lifted by the push-pull solenoid 16, so that the lifter 15 lifts the wafer slightly from the upper surface of the wafer suction unit 12 of the wafer gripping unit 1. FIG. 3 shows a state where the lifter 15 is lifted to support the back surface of the wafer.
Then, after aligning the concave portion 14 of the gripper 1 with the approach direction of the end effector 13, the lifter 15 is lowered to place the wafer on the gripper 1 again.
Thereafter, the end effector 13 enters the recess 14 and receives the wafer, thereby completing a series of operations.

In this embodiment, the notch alignment and center alignment of the wafer are finished, the lifter 15 is lifted to support the wafer, and the concave portion 14 is rotated so as to face the entry direction of the end effector 13, and then the lifter 15 is lowered. Then, the wafer is placed again on the gripping unit 1, but the recess 14 of the gripping unit 1 is aligned with the entry direction of the end effector 13 while the lifter 15 is lifted to support the back surface of the wafer. Sometimes, the end effector 13 may enter the recess 14 to remove the wafer. In this way, a series of operation times can be shortened.
On the other hand, in a series of operations, if there is time until the end effector 13 of the wafer transfer apparatus removes the wafer that has been aligned, the wafer that has been aligned is lifted with the lifter 15 supported. 15 and the grip portion 1, the recess 14 of the grip portion 1 is aligned with the direction in which the end effector 13 enters as described above, and then the lifter 15 is lowered to move the wafer to the grip portion 1. Alternatively, the wafer may be placed again, and the wafer may be sucked again by the wafer suction unit 12 to be on standby. In this way, alignment accuracy can be maintained.

  FIG. 4 is a top view showing another embodiment of the pre-aligner apparatus of the present invention. FIG. 5 is a perspective view of only the grip portion. In this embodiment, two concave portions 14 of the wafer gripping portion 1 are provided. That is, four wafer suction portions 12 are formed. In this case, since the position where the end effector 13 of the wafer transfer apparatus can enter is two places as compared with the first embodiment, when the wafer is lifted by the lifter 15, the recess 14 is in the direction in which the end effector 3 can enter. Less time is required to move it to face.

As described above, according to the present invention, a wafer is transferred to and from the end effector 13 that grips the center of the back surface of the wafer by the recess 14 of the wafer gripper 1. In the series of alignment operations, the lifter can be moved up and down with a very small stroke, and therefore, the structure of the lifter lifting mechanism is simple and an inexpensive pre-aligner device can be provided.
Further, by combining the pre-aligner device and the wafer transfer device, an inexpensive wafer transfer system with improved throughput can be provided.

DESCRIPTION OF SYMBOLS 1 Gripping part 2 Rotating shaft 3 Rotating base 4 A pulley 5 Bearing 6 B pulley 7 Rotating servo motor 8 Rotating part base 9 Rotary joint 10 XY table 11 Notch detection sensor 12 Wafer adsorption part 13 End effector 14 Recess 15 Lifter 16 Push-pull solenoid 17 Lifter base 18 Lifter stopper

Claims (10)

In a pre-aligner device that holds and rotates a wafer, detects an outer periphery of the wafer by a sensor, and rotates at least the wafer in a desired direction using detection information of the sensor.
The holding member for holding the wafer is formed with a suction surface that contacts and holds the back surface of the wafer, and a recess into which an end effector of a wafer transfer device that transfers the wafer to the suction surface can enter. A pre-aligner device characterized by being formed.   The pre-aligner device according to claim 1, wherein the recess has a shape having a step larger than a thickness of the end effector and a width larger than a width of the end effector.   The pre-aligner apparatus according to claim 1, wherein the end effector is formed in a paddle shape and sucks a back surface of the wafer to convey the wafer.   When the wafer is supported around the gripping member, the wafer can be raised to a position where the back surface of the wafer is higher than the upper surface of the suction surface, and the wafer is held by the suction surface. The pre-aligner device according to claim 1, further comprising a lifter that can be lowered to a position lower than the back surface of the pre-aligner.   The pre-aligner device according to claim 1, wherein the concave portion is formed at two or more locations on the gripping member.   A wafer transfer system comprising the pre-aligner device according to claim 1 and a wafer transfer device having the end effector.   A semiconductor manufacturing apparatus comprising the wafer transfer system according to claim 6.   A semiconductor inspection apparatus comprising the wafer transfer system according to claim 6. A gripping member having a suction surface for sucking a wafer and having a concave portion larger than an end effector of a wafer transfer device capable of transporting the wafer on the suction surface; and a back surface of the wafer when the wafer is supported A lifter that can be raised to a position higher than the upper surface of the suction surface and can be lowered to a position lower than the rear surface of the wafer when the wafer is held on the suction surface, and a turning mechanism that rotates the gripping member And a sensor for detecting an outer periphery of the wafer held by the holding member, and a method of aligning the wafer in a pre-aligner device that rotates at least the wafer in a desired direction using detection information of the sensor. There,
The end effector enters the recess to place the wafer on the suction surface,
Sucking the wafer by the suction surface;
Rotate the gripping member that adsorbs the wafer,
Detecting the outer periphery of the wafer with the sensor while performing the rotation,
Rotate the wafer in a desired direction based on the outer circumference information of the wafer from the sensor,
The suction surface releases the suction of the wafer;
The lifter supports the wafer higher than the suction surface,
Rotate the gripping portion so that the concave portion faces the direction of the end effector,
The lifter places the wafer on the suction surface,
A wafer alignment method, wherein the wafer is removed by the end effector entering the recess.   10. The wafer alignment method according to claim 9, wherein the suction surface sucks the wafer again after the lifter places the wafer on the previous suction surface until the end effector removes the wafer. A wafer alignment method characterized by the above.

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