Wafer transfer device and wafer transfer method

Abstract

In a wafer transfer device in which a wafer transfer robot transfers wafers via an aligner, high transfer throughput is achieved. The wafer transfer device includes a wafer transfer robot, and the separation dimension between a pair of wafer holding rods that form the finger portion of the wafer transfer robot is made larger than the dimension in the width direction of the main body portion of the aligner included in the wafer transfer device. Further, the problem is solved by configuring the lifting mechanism included in the wafer transfer device so that the finger portion can move downward to the main body portion of the aligner.

Description

Technical Field

[0001] The present invention relates to a wafer transfer device for transferring semiconductor wafers between a cleaning container and various processing devices in a clean environment, and more particularly to a wafer transfer device including a transfer robot having a wafer holding unit and an aligner for positioning a semiconductor wafer, and a method for transferring a wafer. Background Art

[0002] In a semiconductor wafer (hereinafter referred to as a wafer), various fine processes such as resist coating, exposure, and development are performed on the surface by various processing apparatuses. In order to perform these various processes, the wafer is accommodated in a clean container that can be sealed in a clean environment called a clean room where the external atmosphere is isolated and the floating amount of dust is small, and is transferred between the respective processing apparatuses. Each processing apparatus includes a wafer transfer device and a processing device. A FOUP (Front Opening Unifate Pod), which is one of the clean containers, transferred to the processing apparatus is placed on a FOUP opening / closing device that is called a loading port of the wafer transfer device and is a part of the processing apparatus. A wafer transfer robot is provided inside the wafer transfer device, and wafers are exchanged between the FOUP placed on the loading port and the respective processing devices. When the lid of the FOUP is opened while maintaining the clean environment, the wafer W accommodated in the FOUP is taken out by the wafer transfer robot in the internal space of the wafer transfer device and transferred to the processing device that performs various processes. The wafer transfer device is covered with a wall that separates the surroundings from the external environment, and an FFU (Fan Filter Unit) is provided above the wafer transfer device. The FFU supplies highly clean air as a downward laminar flow to the internal space of the wafer transfer device. Through this wall and the FFU, the internal space, which is the space where the wafer moves inside the wafer transfer device, is maintained at a high cleanliness.

[0003] Patent Document 1 discloses a horizontal multi-joint robot (hereinafter referred to as a "transfer robot") that includes a base disposed on the processing device side in a transfer space, a lower robot arm that can rotate relative to the base, an upper robot arm that can rotate relative to the lower robot arm, and a robot hand that can rotate relative to the upper robot arm. The upper and lower robot arms of the horizontal multi-joint robot have a length longer than 1 / 2 of the depth dimension of the transfer space formed by the front and rear walls, and each robot arm and the robot hand are configured to be able to operate independently by a separate motor. In this way, by making the robot arm longer than 1 / 2 of the depth dimension of the transfer space, it is possible to transfer the wafer to a distant position without providing a linear drive mechanism that moves the transfer robot in the left-right direction between the distant loading port and the transfer robot.

[0004] In addition, an aligner for adjusting the placement position of a wafer is provided in the wafer transfer device of Patent Document 1. The aligner holds the wafer transferred by the transfer robot through a holding unit, rotates the held wafer, and thereby scans the peripheral portion of the wafer using a sensor to detect the offset amount (position offset) of the wafer placement position. In addition, based on the result of detecting notch portions such as notches and orientation flats formed in the peripheral portion of the wafer, the rotational orientation (rotational positioning) of the wafer is performed.

[0005] The aligner is disposed in the same transfer space as the wafer transfer robot. The wafer taken out from the FOUP is temporarily transferred to the aligner before being transferred by the wafer transfer robot to the processing device, and positioning is performed so that the holding position of the wafer on the robot arm becomes a predetermined given position. Then, the wafer is transferred from the aligner to the processing device by the wafer transfer robot. In addition, when returning the wafer after the processing in the processing device to the FOUP, it is also transferred from the processing device to the aligner by the wafer transfer robot, inspected by an inspection device disposed near the aligner, and then transferred to the FOUP.

[0006] In the wafer transfer robot described in Patent Document 1, by separately rotating the upper robot arm, the lower robot arm, and the robot hand, it is possible to transfer the wafer to a desired position among the FOUP on the loading port, the processing device, and the aligner without providing a linear drive mechanism for moving the wafer transfer robot in the left-right direction.

[0007] However, in the horizontal multi-joint robot described in Patent Document 1, there is a problem such as when performing the transfer operation of another wafer during the period from when the wafer is transferred to the aligner until the aligner finishes the alignment operation. In order to transfer to the transfer operation of another wafer after transferring the wafer to the aligner, the horizontal multi-joint robot must retract the wafer hand in a manner that does not contact the wafer placed on the aligner and the wafer holding unit, and then start the next wafer transfer operation. As in the horizontal multi-joint robot described in Patent Document 1, when the lengths of the upper and lower robot arms are set to be longer than 1 / 2 of the depth dimension of the transfer space, the operation range related to the rotational movement of each of the upper and lower robot arms is restricted. As a result, the operation of the robot arm takes time and the throughput decreases. In particular, in order to effectively utilize the limited space in the clean room, the occupied area of the wafer transfer device is reduced as much as possible, and the transfer space itself is configured to be narrow. Therefore, as a result, the operation is restricted due to the narrow operation range of the robot arm, and the robot arm must perform complex operations.

[0008] Prior Art Documents

[0009] Patent Documents

[0010] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2008-28134 Summary of the Invention

[0011] (Problems to be Solved by the Invention)

[0012] The present invention has been made in view of such problems, and an object thereof is to provide a wafer transfer device that can achieve high transfer throughput regardless of the length of a robot arm when a wafer transfer robot transfers a wafer via an aligner. Another object of the present invention is to provide a wafer transfer method using a wafer transfer robot.

[0013] (Technical Solution for Solving the Problems)

[0014] To solve the above problems, a wafer transfer device of the present invention includes: an aligner that holds a wafer on a wafer stage and detects a peripheral portion of the wafer; and a transfer robot that holds and transfers the wafer between a loading port, the aligner, and a processing device. The transfer robot includes: an arm body having at least two arms, one ends of the respective arms being connected to be rotatable with respect to each other; a finger portion rotatably mounted at a front end of the arm body and holding the wafer; an arm body drive mechanism that moves the arm body; a finger portion drive mechanism that rotates the finger portion in a horizontal plane; and a lifting mechanism that moves the arm body in a vertical direction. A separation dimension between a pair of wafer holding rods included in the finger portion is larger than a dimension in a width direction of a main body portion of the aligner in an access area of the wafer holding rod to the main body portion of the aligner, and the lifting mechanism has an operation range that can move the finger portion below the main body portion of the aligner.

[0015] Preferably, in the wafer transfer device of the present invention, a difference between the separation dimension of the pair of wafer holding rods and the dimension in the width direction of the main body portion is larger than an allowable offset dimension of the wafer in the width direction. Further, in the wafer transfer device of the present invention, the wafer stage may be a suction type wafer stage that sucks and holds the wafer, and the finger portion may be a suction type finger portion that sucks and holds the wafer.

[0016] Furthermore, preferably, a pair of wafer holding pads and wafer contact portions for adsorbing the wafer are arranged on the adsorption finger portion. When viewed from above the center of the wafer held by the adsorption finger portion, it is arranged within a triangle formed by connecting the pair of wafer holding pads and the wafer contact portions. When the adsorption finger portion is at a position for transferring the wafer to and from the adsorption wafer base, the rotation center axis of the adsorption wafer base is arranged within the triangle when viewed from above. Additionally, it may be configured such that the adsorption aligner includes a moving mechanism for moving the adsorption wafer base in a horizontal plane.

[0017] In addition, in the wafer transfer device of the present invention, it may also be that the wafer base is a clamp-type wafer base that clamps the peripheral portion of the wafer, and the finger portion is a clamp-type finger portion that clamps the peripheral portion of the wafer.

[0018] In addition, to solve the above problems, the wafer transfer method of the present invention is a wafer transfer method performed between a wafer base that holds a wafer and an aligner that inspects the peripheral portion of the wafer and a transfer robot that holds the wafer on a finger portion and transfers it, and includes the following steps: a step in which the transfer robot operates an arm body drive mechanism that moves the arm body, a finger portion drive mechanism that rotates the finger portion in a horizontal plane, and a lifting mechanism that moves the arm body in a vertical direction to place the wafer held on the finger portion on the wafer base provided in the aligner; a step in which, after placing the wafer on the wafer base, the lowering operation of the lifting mechanism is continued to lower the finger portion below the aligner; and a step in which the arm body drive mechanism and the finger portion drive mechanism are operated to retract the finger portion from the aligner.

[0019] In addition, the wafer transfer method of the present invention includes the following steps: a step of detecting a position deviation of the wafer by detecting a peripheral portion of the wafer held on a wafer stage by the aligner; a step of causing the transfer robot to operate an arm driving mechanism that moves the arm body, a finger driving mechanism that rotates the finger portion in a horizontal plane, and a lifting mechanism that moves the arm body in a vertical direction, so that the finger portion moves below the aligner; and a step of causing the finger portion that has moved below the aligner to rise above the wafer stage through the operation of the lifting mechanism, thereby holding the wafer placed on the wafer stage. Additionally, it may further include the following steps: a step of causing the transfer robot to move the finger portion in a direction that cancels out the position deviation of the wafer detected by the aligner before operating the lifting mechanism to raise the finger portion. Furthermore, it may include the following steps: before the transfer robot operates the lifting mechanism to raise the finger portion, the aligner moves the wafer stage in a horizontal plane in a direction that cancels out the detected position deviation of the wafer.

[0020] (Advantages of the Invention)

[0021] According to the present invention, in a wafer transfer apparatus in which a wafer transfer robot transfers wafers via an aligner, high transfer throughput can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a top view showing the structure of a wafer transfer apparatus according to an embodiment of the present invention.

[0023] Figure 2 It is a side view showing the structure of a wafer transfer apparatus according to an embodiment of the present invention.

[0024] Figure 3 It is a cross-sectional view showing a wafer transfer robot according to an embodiment of the present invention.

[0025] Figure 4 It is a view showing upper and lower finger portions according to an embodiment of the present invention.

[0026] Figure 5 It is a cross-sectional view showing an aligner according to an embodiment of the present invention.

[0027] Figure 6 It is a view showing the positions of a finger portion and an aligner according to an embodiment of the present invention.

[0028] Figure 7 It is a view showing a wafer placement operation of a wafer transfer robot according to an embodiment of the present invention.

[0029] Figure 8is a block diagram schematically showing the configuration of the control system of the wafer transfer device 1 according to an embodiment of the present invention.

[0030] Figure 9 is a diagram showing the transfer operation performed by a conventional wafer transfer robot.

[0031] Figure 10 is a diagram showing the transfer operation performed by the wafer transfer robot according to an embodiment of the present invention.

[0032] Figure 11 is a diagram showing the transfer operation performed by the wafer transfer robot according to an embodiment of the present invention.

[0033] Figure 12 is a diagram showing the retraction operation performed by the wafer transfer robot according to an embodiment of the present invention.

[0034] Figure 13 is a diagram showing an aligner including a first moving mechanism according to an embodiment of the present invention.

[0035] Figure 14 is a diagram showing an aligner including a first moving mechanism and a second moving mechanism according to an embodiment of the present invention.

[0036] Figure 15 is a diagram showing a clamping finger portion and a clamping aligner according to an embodiment of the present invention.

[0037] Figure 16 is a diagram showing the transfer operation performed by the wafer transfer robot according to an embodiment of the present invention. Detailed Embodiments

[0038] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 is a top view showing the configuration of the wafer transfer device 1 according to an embodiment of the present invention, Figure 2 is showing Figure 1 a left sectional side view of the wafer transfer device in a state where it is cut along the inner side of the left side wall. The wafer processing device 3 is omitted in Figure 2 . Further, Figure 3 is showing Figure 1 a cross-sectional view of an embodiment of the wafer transfer robot 7 included in the wafer transfer device 1 shown. Figure 1The wafer transfer device 1 shown is used to transfer the wafer W between the FOUP 2 and the wafer processing device 3 in the transfer space 4 while maintaining a clean environment. The wafer transfer device 1 includes: a frame 5 that forms the transfer space 4; a lid opening / closing device that is fixed to the frame 5, mounts the FOUP 2 that houses the wafer W, and opens and closes the lid of the FOUP 2; a wafer transfer robot 7 that is disposed in the transfer space 4 and transfers the wafer W between the FOUP 2 and the substrate processing device; and an aligner 8 that positions the wafer W. In addition, above the transfer space 4, there is an FFU 9 that supplies clean air to the transfer space 4 in a downward laminar flow manner. Further, a bottom plate 10 having a given opening is fixed to the bottom surface frame 5a of the transfer space 4, and the air supplied from the FFU 9 is discharged from the transfer space 4 to the outside through the opening of the bottom plate 10. In addition, a front wall 11 that hermetically seals the transfer space 4 from the outside is fixed to the wall surface on the side of the transfer space 4 where the loading port 6 is disposed, and a rear wall 12 is fixed to the surface of the transfer space 4 opposite to the front wall 11. Further, an opening 13 for transferring the wafer W between the transfer space 4 and the wafer processing device 3 is formed in the rear wall 12.

[0039] Furthermore, in the transfer space 4 of the wafer transfer device 1 of the present embodiment, a differential pressure plate 16 that is divided into a substrate transfer region 14 that requires high cleanliness and a low-pressure region 15 below it is disposed. The differential pressure plate 16 is a plate-shaped member disposed horizontally in the transfer space 4, and divides the substrate transfer region 14 and the low-pressure region 15 so that gas can flow through. In addition, when the arm body 18 included in the wafer transfer robot 7 is moved to the lowermost position by the lifting mechanism 19, the differential pressure plate 16 is also disposed at a position where it does not contact the arm body 18 and is disposed below the arm body 18. In addition, the differential pressure plate 16 is formed of a perforated metal plate having a plurality of through holes with a given diameter provided at a given interval. Through this differential pressure plate 16, the upper substrate transfer region 14 is maintained at a higher pressure than the lower low-pressure region 15, and dust generated inside the wafer transfer robot 7 and flowing out to the low-pressure region 15 does not invade the upper substrate transfer region 14. In addition, dust generated in the upper substrate transfer region 14 flows out to the lower low-pressure region 15 through the through holes of the perforated metal, so the substrate transfer region 14 is maintained in a highly clean state.

[0040] The wafer transfer robot 7 of the present embodiment is a horizontal multi-joint type SCARA robot, and at least includes: finger portions 17 that hold the wafer W; an arm body 18 that supports the finger portions 17 so as to be rotatable and movable to a given position within a horizontal plane; an arm drive mechanism that drives the arm body 18; a lifting mechanism 19 that moves up and down in the vertical direction while supporting the arm body 18 in a rotatable state; and a base 20 that fixes the lifting mechanism 19.

[0041] The base 20 is fixed to a position on the floor frame 5a forming the transfer space 4 near the back wall 12. An elevating mechanism 19 and an elevating drive motor 21 for driving the elevating mechanism 19 are installed on the base 20. A rotation shaft (not shown) of the elevating drive motor 21 and a ball screw mechanism of the elevating mechanism 19 are connected to each other via a pulley and a belt (not shown). Therefore, when the elevating drive motor 21 operates, a moving member screwed to the ball screw mechanism constituting the elevating mechanism 19 moves up and down. An elevating plate 23 is fixed to the moving member via a bracket 22. A base end portion of a first arm 24 constituting the arm body 18 is mounted on the elevating plate 23 via a bearing so as to be rotatable about a straight line C1 as shown in Figure 3 the rotation center. Moreover, a first arm drive motor 25 is installed on the elevating plate 23. A pulley fixed to the rotation shaft of the first arm drive motor 25 and a pulley fixed coaxially with the base end portion of the first arm 24 about the straight line C1 are connected via a belt, thereby constituting an arm drive mechanism of the first arm. According to this structure, when the first arm drive motor 25 operates, the first arm 24 rotates with respect to the elevating plate 23.

[0042] At the front end portion of the first arm 24, a base end portion of a second arm 26, which is another arm constituting the arm body 18, is mounted via a bearing so as to be rotatable about a straight line C2 extending in the vertical direction as the rotation center. The first arm 24 has a hollow box-shaped or tubular structure, and a second arm drive motor 27 for driving the second arm 26 is fixed inside. A pulley fixed coaxially to the rotation shaft of the second arm drive motor 27 and a pulley coaxially fixed to the base end portion of the second arm 26 about the straight line C2 are connected via a belt to a pulley. According to this structure, when the second arm drive motor 27 operates, the second arm 26 rotates with respect to the first arm 24.

[0043] The base end portions of the upper finger portion 17a and the lower finger portion 17b that hold the wafer W are respectively mounted to the front end portion of the second arm 26 via bearings in such a manner that they can rotate independently about a common straight line C3 (hereinafter referred to as "rotation axis C3") extending in the vertical direction as the rotation center. The second arm 26 has a hollow box-shaped or tubular structure, and drive mechanisms (finger drive mechanisms) 29a and 29b for rotating the upper and lower finger portions 17a and 17b respectively are disposed in the internal space. The drive mechanism 29a for rotationally driving the upper finger portion 17a is composed of an upper finger portion drive motor 30 and a belt that loops around a pulley fixed to the upper finger portion 17a and a pulley fixed to the rotation shaft of the upper finger portion drive motor 30. In addition, the drive mechanism 29b for rotationally driving the lower finger portion 17b is composed of a lower finger portion drive motor 31 and a belt that loops around a pulley fixed to the lower finger portion 17b and a pulley fixed to the rotation shaft of the lower finger portion drive motor 31. The upper finger portion drive motor 30 and the lower finger portion drive motor 31 are fixed to the second arm 26. Pulleys are respectively fixed to the rotation shafts of the upper finger portion drive motor 30 and the lower finger portion drive motor 31, and pulleys centered on the rotation axis C3 are coaxially fixed to the base end portions of the upper finger portion 17a and the lower finger portion 17b respectively. The pulleys fixed to the upper finger portion 17a and the lower finger portion 17b are arranged so as to be vertically offset from each other with the pulley fixed to the lower finger portion 17b being above. In addition, the pulleys of the upper finger portion drive motor 30 and the lower finger portion drive motor 31 are also arranged so as to be vertically offset from each other with the pulley of the lower finger portion drive motor 31 being above. These corresponding pulleys and the rotation shafts of the respective drive motors are connected via belts, constituting the arm drive mechanism of the second arm. According to this structure, when the upper finger portion drive motor 30 operates, the upper finger portion 17a rotates independently relative to the second arm 26, and when the lower finger portion drive motor 31 operates, the lower finger portion 17b rotates independently relative to the second arm 26.

[0044] In addition, as long as each motor provided in the wafer transfer robot 7 of the present embodiment is a motor capable of performing rotational angle control based on the control device, it may be any known motor such as a servo motor, a stepping motor, or a direct drive motor. In addition, it is preferable to provide an encoder for detecting the rotational angle of the rotation shaft in each motor. In addition, among the motors provided in the wafer transfer robot 7 of the present embodiment, a reduction gear integrated type gear motor in which the motor main body and the reduction gear are arranged in the same housing is used, but a structure provided with a reduction gear independent of each motor may also be adopted. In addition, a structure without a reduction gear may also be adopted. The wafer transfer robot 7 of the present embodiment preferably includes a lifting mechanism 19, a first arm 24, a second arm 26, and a position detection sensor (not shown) for detecting the positions of the upper and lower finger portions 17a and 17b.

[0045] Output signals from these respective position detection sensors or respective encoders are sent to a robot control unit 32 provided in the wafer transfer robot 7. Figure 8 ) The robot control unit 32 includes a CPU that performs arithmetic processing, a receiving device that receives signals output from the respective sensors, a transmitting device that sends control signals to electrical components such as motors, and a storage unit that stores programs for operating the robot and various setting data and teaching data. The robot control unit 32 operates the respective motors based on a pre-stored program to move the upper finger portion 17a and the lower finger portion 17b (hereinafter, the upper and lower finger portions 17a and 17b may sometimes be collectively referred to as "finger portion 17") along a desired path. In addition, the robot control unit 32 includes a communication unit that exchanges various signals with a control PC that controls the wafer transfer device 1, and operates the wafer transfer robot 7 in accordance with an operation instruction from the control PC.

[0046] Figure 4 is a plan view for explaining the structures of the upper and lower finger portions 17a and 17b of the present embodiment. Since the upper finger portion 17a and the lower finger portion 17b have the same structure, in Figure 4 , only one finger portion is shown as "finger portion 17". Figure 4 shows the position of the finger portion 17 and the wafer W held by the finger portion 17. The wafer W is held at a reference position (indicated by a two-dot chain line) determined by the design of the upper and lower finger portions 17a and 17b, respectively. The upper finger portion 17a and the lower finger portion 17b of the present embodiment are each composed of a holding portion 33 that holds the wafer W and a wrist portion 34 that supports the base end of the holding portion 33. The finger portion 17 of the present embodiment is a wafer adsorption type finger portion that fixes the wafer W to the finger portion 17 by evacuating air near the front end portion of the finger portion 17 in a state where the wafer W is lifted from below. Therefore, it is connected to a vacuum source (not shown) provided in the clean room via a pipe member 35.

[0047] In addition, in the present embodiment, an example is shown in which the holding portion 33 fits together an upper member 36 and a lower member 37 that are Y-shaped with the front end divided into two branches. At each front end portion of the upper member 36 that is divided into two branches in a Y shape, wafer holding pads 38a and 38b for contacting the lower surface of the wafer W and adsorbing the wafer W are formed in a shape that bulges compared to the surroundings. In addition, oblong depressions are formed at the tops of the respective wafer holding pads 38a and 38b, and through holes 40 for communicating with a vacuum flow path 39 formed in the lower member 37 are formed at the bottoms of the depressions. Further, wafer contact portions 41 having the same height as the respective wafer holding pads 38a and 38b are provided at other positions on the upper surface of the upper member 36, and the wafer W is supported at these three points of the respective wafer holding pads 38a and 38b and the wafer contact portions 41. A Y-shaped groove for forming the vacuum flow path 39 is provided in the lower member 37, and a joint for connecting to a vacuum source is connected to the base end portion of the groove. A piping member 35 communicating from the vacuum source is connected to the joint of the holding portion 33 via a solenoid valve 42 disposed in the wrist portion 34. The solenoid valve 42 is electrically connected to the robot control portion 32, and by receiving an opening / closing signal of the solenoid valve 42 sent from the robot control portion 32, the wafer transfer robot 7 can hold the wafer W on the finger portion 17 or release the holding.

[0048] The wafer holding pads 38a and 38b are respectively disposed at the front end portions of a pair of wafer holding rods 43a and 43b that branch into a Y shape. In a plan view, the upper and lower finger portions 17a and 17b of the present embodiment are preferably formed to be line-symmetric in a horizontal plane with respect to a straight line L1 that connects the rotation axis C3 of the upper and lower finger portions 17a and 17b and the center line in the length direction of the holding portion 33. In addition, the wafer W is supported from below by abutting against the left and right wafer holding pads 38a and 38b and the wafer contact portion 41, and the wafer W is adsorbed and held by evacuating the left and right wafer holding pads 38a and 38b. As a result, the wafer W does not shift in position due to the transfer operation of the wafer transfer robot 7 and is held on the upper and lower finger portions 17a and 17b. In addition, in order to enable the upper and lower finger portions 17a and 17b to stably hold the wafer W, it is desirable that the wafer W be supported such that the wafer center P1 is located inside a triangle T1 formed by a straight line connecting the left and right wafer holding pads 38a and 38b and the wafer contact portion 41. As a result, even if the evacuation of the wafer holding pads 38a and 38b is interrupted, the wafer W is supported at the normal position on the upper and lower finger portions 17a and 17b.

[0049] In addition, the upper and lower finger portions 17a and 17b of the present embodiment support the wafer W in the vertical direction by bringing the wafer W into contact with at least three points of the left and right wafer holding pads 38a and 38b and the wafer contact portions 41, but the present invention is not limited thereto. For example, the number of the wafer holding pads 38a and 38b for vacuum-sucking the wafer W may be one, and the number of the wafer contact portions 41 may be two or more. Alternatively, the wafer contact portions 41 may not be provided, and the number of the wafer holding pads 38a and 38b may be three or more. However, in this case, the center P1 of the wafer W is also preferably disposed inside a triangle T1 formed by a straight line connecting at least three support points among the holding pads 38 and the wafer contact portions 41 disposed on the upper and lower finger portions 17a and 17b.

[0050] Next, the aligner 8 included in the wafer transfer device 1 of the present embodiment will be described. Figure 5 FIG. is a cross-sectional view schematically showing the internal structure of the aligner 8 of the present embodiment. The aligner 8 of the present embodiment includes: a base member 44; a wafer stage 45 that is rotatably provided on the base member 44 and adsorbs and holds the wafer W; an aligner motor 46 that rotationally drives the wafer stage 45 about a rotation axis C4 (hereinafter referred to as "rotation axis C4") via a belt 51; a wafer detection sensor 47 that detects the peripheral portion of the wafer W held on the wafer stage 45 and rotating; and an aligner control unit 53 (see Figure 8 ).

[0051] The wafer stage 45 is fixed to the upper portion of a cylindrical shaft 28 that is rotatably mounted on the base member 44 via a bearing, and is configured to rotate together with the shaft 28 about a rotation axis C4 extending in the vertical direction. A driven pulley 49 is fixed to the lower end of the shaft 28. The aligner motor 46 is fixed to the base member 44, and a driving pulley 50 is fixed to the front end of the rotation shaft 48 of the aligner motor 46. The belt 51 is wound around the driving pulley 50 and the driven pulley 49. Thus, by the rotational operation of the aligner motor 46, the wafer stage 45 rotates about the rotation axis C4. Further, an encoder (not shown) for detecting the rotation angle of the rotation shaft 48 is provided on the rotation shaft 48, and a detection signal of the encoder is sent to the aligner control unit 53. In addition, the aligner motor 46 included in the aligner 8 of the present embodiment uses a reduction gear integrated type gear motor in which the main body and the reduction gear are disposed in the same housing, but may be configured such that an independent reduction gear is provided in the aligner motor 46.

[0052] The wafer base 45 is a cylindrical member having a vertically penetrating hole in the central portion and can be formed of a resin material. On the upper surface of the wafer base 45, i.e., the surface on which the wafer W is placed, a flow path for vacuum-sucking the wafer W is formed. A rotary joint is connected to a shaft 28 that is fixed below the wafer base 45 and rotates together with the wafer base 45. The rotary joint is connected to a vacuum source such as a vacuum pump (not shown) via a pipe member 52. The rotary joint is composed of a fixed portion connected to the pipe member 52 and a rotating portion connected to the shaft 28, and the fixed portion and the movable portion are connected by a seal such as a bearing and an O-ring. The rotary joint rotatably supports the wafer base 45 and the shaft 28, and transmits the suction force from the vacuum pump to the inside of the wafer base 45 without air leakage.

[0053] An electromagnetic valve 55 is disposed in the middle of the pipe member 52, and evacuation of the wafer base 45 and release of the vacuum pressure are performed by the operation of the electromagnetic valve 55. In the middle of the pipe member 52 connecting the electromagnetic valve 55 and the wafer base 45, a pressure sensor 56 for detecting the pressure inside the pipe member 52 is provided. By detecting the pressure inside the pipe member 52 using the pressure sensor 56, it is detected whether the wafer W is placed on the wafer base 45 and whether the placement is normal.

[0054] It should be noted that the wafer base 45 may be made of a material that is easy to process, generates less dust, and does not damage the wafer W. For example, it can be made of polytetrafluoroethylene. In addition to polytetrafluoroethylene, resin materials such as polyether ether ketone can also be used.

[0055] The wafer detection sensor 47 detects a notch and an orientation flat surface formed on the peripheral portion of the wafer W held and rotated on the wafer base 45, and detects the peripheral portion of the wafer W, thereby detecting the position offset amount and the position offset direction between the center P1 of the wafer W and the rotation axis C4 of the wafer base 45. The wafer detection sensor 47 of the present embodiment is a transmissive sensor that detects the transmitted light of the detection light 47a emitted from the light projecting portion by the detection portion. In addition, the wafer detection sensor 47 of the present embodiment is a line sensor, and is configured such that a plurality of light sensors arranged in a straight line detect the detection light 47a emitted from a plurality of light projectors (light projecting portions) arranged in a straight line, and the position in the radial direction of the wafer W is measured with respect to the peripheral edge of the wafer W held on the wafer base 45. In addition, the light projectors and the light sensors of the wafer detection sensor 47 provided in the aligner 8 of the present embodiment are arranged to coincide with a straight line L2 extending in the long side direction (X direction) of the aligner 8 passing through the rotation axis C3 of the finger portion 17 and the rotation axis C4 of the wafer base 45 in a plan view. Refer to Figure 6 。

[0056] In addition, the aligner 8 in the present embodiment is provided with an aligner control unit 53. The aligner control unit 53 is electrically connected to the aligner motor 46, the encoder, the solenoid valve 55, and the wafer detection sensor 47. The aligner control unit 53 controls the rotation of the aligner motor 46, obtains the position information of the wafer and the rotation angle information of the motor based on the electrical signals from the wafer detection sensor 47 and the encoder, and thereby calculates the position offset amount of the wafer W, the direction of the position offset, the notch, and the position of the orientation flat. In addition, the aligner control unit 53 controls the solenoid valve 55 to perform the adsorption and holding of the wafer W on the wafer stage 45 and the release of the adsorption.

[0057] The aligner control unit 53 in the present embodiment includes a CPU that performs arithmetic processing, a receiving device that receives signals output from each sensor, a transmitting unit that transmits output signals to the aligner motor 46 and the solenoid valve 55, and a storage unit that stores a program for operating the aligner motor 46 and various setting data and teaching data. The aligner control unit 53 performs the positioning of the wafer W, the detection of the notch, and the detection of the orientation flat based on a program provided in advance. In addition, the aligner control unit 53 includes a communication unit that performs signal transmission and reception with the control PC included in the wafer transfer device 1. The aligner control unit 53 performs position offset detection of the wafer W, detection of the position of the notch and the orientation flat, and alignment of the rotation direction of the wafer W according to the operation instruction from the control PC.

[0058] The aligner 8 in the present embodiment is fixed to a vertically erected frame 5b via a bracket 54. After the wafer transfer robot 7 operates each motor to take out the wafer W accommodated in the FOUP 2 from the FOUP 2, the wafer W is placed on the wafer stage 45 and separated from the wafer stage. Then, when the alignment operation of the aligner 8 is completed, the wafer transfer robot 7 moves the finger portions 17 to a position where the position offset of the wafer W after alignment is eliminated, holds the wafer W, and transfers it from the wafer stage 45 of the aligner 8 to the wafer transfer position of the wafer processing device 3.

[0059] Next, the relationship between the finger portions 17a and 17b included in the wafer transfer robot 7 in the present embodiment and the aligner 8 will be described. Figure 6 FIG. shows the wafer transfer robot 7 in the present embodiment placing the wafer W held at a "given position on the finger portions 17a and 17b" on a "given position on the wafer stage 45". In addition, the "given position on the finger portions 17a and 17b" is a position that is predetermined in design when the finger portions 17a and 17b hold the wafer W. This given position is taught to the transfer robot 7 through a position teaching operation performed by the installation operator before actual operation. Here, the position information obtained through the position teaching operation of the installation operator is stored in the robot control unit 32 included in the wafer transfer robot 7.

[0060] In addition, the "given position on the wafer stage 45" is similarly taught by the position teaching operation performed by the setting operator, and the position information obtained through the position teaching operation of the setting operator is stored in the robot control unit 32 provided in the wafer transfer robot 7. In the wafer transfer robot 7 of the present embodiment, when holding the wafer W, teaching is performed in such a manner that the center P1 of the wafer W is located on the center line L1, which is the axis of symmetry extending in the horizontal direction of the holding portions 33 formed symmetrically on the left and right. In addition, when placing the wafer W held by the holding portion 33 on the wafer stage 45, teaching is performed in such a manner that the center P1 of the wafer W coincides with the rotation axis C4 of the wafer stage 45.

[0061] Here, the width dimension D1 of the main body portion 61 of the aligner 8 of the present embodiment, which is provided with the wafer stage 45 and the driven pulley 49, and the separation dimension D2 between the left and right wafer holding rods 43a and 43b formed at the front end portion of the holding portion 33 are configured such that D1 is less than D2. In the aligner 8 of the present embodiment, components constituting the aligner 8 are extremely suppressed from being arranged in the main body portion 61 around the area where the wafer W is placed, and are arranged in the electrical installation portion 60 as much as possible.

[0062] The width dimension D1 refers to the dimension of the main body portion 61 in the direction orthogonal to the center line L2 when the upper and lower finger portions 17a and 17b are in the posture of placing the wafer W on the wafer stage 45 or in the posture of picking up the wafer W placed on the wafer stage 45, and the separation dimension D2 refers to the interval between the wafer holding rods 43a and 43b in the direction orthogonal to the center line L2 at this time.

[0063] In addition, the width dimension D1 of the main body does not need to be such that the entire width dimension of the aligner main body portion is D1 < D2, as long as the width dimension of the aligner main body portion in the area accessed by the finger portions 17a and 17b is D1 < D2. In addition, as in the present embodiment, when the aligner 8 has a substantially rectangular shape in a top view, the width dimension D1 refers to the dimension in the short side direction (Y direction) of the substantially rectangular shape, and in the top view, it is the position sandwiched by the wafer holding rods 43a and 43b of the upper and lower finger portions 17a and 17b, and is the dimension related to the direction in which the wafer holding rods 43a and 43b of the main body portion 61 face each other.

[0064] Thus, by setting D1 < D2, after the wafer transfer robot 7 moves the arm body 18 to move the wafer W held on the finger parts 17a and 17b above the wafer base 45, the lifting mechanism 19 is lowered, and the wafer W is placed on the wafer base 45 by using the finger parts 17a and 17b. It is possible to move the finger parts 17a and 17b in the vertical direction to below the aligner 8 without the lifting mechanism 19 stopping at the placement position. Thereby, precise and accurate movement of the arm body is not required, and it is possible to quickly transfer to the next transfer operation (refer to Figure 7 (a) to (c) of

[0065] In addition, when lifting the wafer W placed on the wafer base 45, after the wafer transfer robot 7 moves the finger parts 17a and 17b to directly below the aligner 8, by raising the finger parts 17 in the vertical direction, the wafer W can be lifted onto the wafer base 45. In the conventional wafer transfer robot 57, after the wafer W is placed on the wafer base 45, considering the risk of interference between the arm body and the wafer, etc., after moving the finger parts horizontally relative to the aligner 8, it transfers to the next transfer operation. However, in the wafer transfer robot 7 of the present embodiment, since the finger parts 17a and 17b directly move below the aligner 8 after placing the wafer W, only the lifting mechanism 19 is operated without operating the arm body 18, and only the finger parts 17a and 17b are lowered to move, so that it is possible to avoid from the aligner 8. Therefore, it is possible to immediately operate the aligner after placing the wafer W, and in addition, it is possible to immediately use the wafer transfer robot 7 for the transfer of other wafers.

[0066] In the present embodiment, an example of a single-axis aligner 8 that only has a drive unit for rotating and moving the wafer W and does not have a position correction unit for correcting the horizontal position offset of the wafer W is shown. In such an aligner 8, regarding the position offset of the wafer W, the wafer transfer robot 7 receives a correction value for correcting the position offset from the aligner 8, and after receiving the wafer W from the wafer base 45 at a pre-taught position, for example, when placing it on the wafer stage 3a of the wafer processing apparatus 3, the correction is performed.

[0067] The wafer transfer robot 7 adds the correction value to the pre-taught position data for the wafer W received from the wafer base 45, and then places the wafer W on the wafer stage 3a, thereby being able to correct the position offset of the wafer W and place the wafer W at an accurate position on the wafer stage 3a. Or, when holding the wafer W on the aligner 8, the wafer transfer robot 7 can also move the finger parts 17a and 17b from the pre-taught position in the direction for correcting the position offset, and then hold the wafer W on the wafer base 45 by using the finger parts 17a and 17b, thereby correcting the position offset.

[0068] In order to perform the correction operation as described above, the horizontal gap ((D2 - D1) / 2) between the main body portion 61 of the aligner 8 and the wafer holding rods 43a and 43b of the finger portions 17a and 17b in the present embodiment is preferably set to a size larger than the allowable position offset of the wafer W accommodated in the FOUP 2 and the allowable position offset (maximum allowable correction amount) within the wafer processing apparatus 3. For example, when the maximum position offset of the wafer W in the FOUP 2 is n millimeters, if the respective gap sizes in the horizontal plane between the left and right side surfaces of the main body portion 61 and the wafer holding rods 43a and 43b are set to a size larger than n millimeters, even if the wafer transfer robot 7 moves the finger portion 17 in the direction of correcting the position offset of the wafer W, the wafer holding rods 43a and 43b will not contact the main body portion 61.

[0069] In addition, the aligner 8 in the present embodiment detects the rotational position offset of the notch formed in the wafer W by the wafer detection sensor 47 and the position offset amount of the wafer W in the X - Y direction, and calculates the position offset amount of the wafer W in the X - Y direction when the notch moves to a given rotational position taught in advance and the correction data for correcting the position deviation in the X - Y direction. Next, the aligner 8 rotates the wafer W so that the notch becomes a given rotational position taught in advance on the periphery of the wafer W. Then, after the wafer transfer robot 7 that has received the correction data for the position offset amount of the wafer W corrects the movement of the finger portion 17 to a position that cancels the position offset, the wafer W on the wafer base 45 is lifted, thereby correcting the position in the rotational direction and the position offset in the XY plane of the wafer W.

[0070] In the aligner 8 of the present embodiment, when the wafer W is placed on the wafer base 45, the wafer transfer robot 7 moves the finger portion 17 above the wafer base 45 and to a position where the center of the wafer W coincides with the rotation axis C4 of the wafer base 45 extending in the vertical direction, and then operates the lifting mechanism 19 to place the wafer W on the wafer base 45. Here, when there is no offset in the holding position of the wafer, the wafer center P1 coincides with the rotation axis C4 of the wafer base 45, and the finger portions 17a and 17b are horizontally symmetric with respect to the straight line L1 connecting the rotation axis C3 and the wafer center P1. In addition, the wafer center P1 is configured to be located inside the triangle T1 surrounded by the straight line connecting the two wafer holding pads 38a and 38b formed on the finger portions 17a and 17b and the wafer contact portion 41 when viewed from above.

[0071] In addition, when the aligner 8 is operating, dust may be generated from the internally disposed motor 46, belt 51, bearings, etc. and discharged to the outside of the aligner 8. The discharged dust flows downward along the downward flow in the transfer space 4 and adheres to the finger portion 17 that has moved below the aligner 8. The dust adhering to the finger portion 17 may move to the wafer W when holding the wafer W. To avoid such a malfunction, the aligner 8 of the present embodiment may also be configured to include a unit that maintains the internal spaces of the electrical mounting portion 60 and the main body portion 61 of the aligner 8 at a negative pressure relative to the transfer space 4.

[0072] As the unit for maintaining a negative pressure, it is preferably provided with an exhaust unit such as a fan or a pump that sucks the gas inside the aligner 8 and discharges it to the outside of the aligner 8. Since the interiors of the electrical mounting portion 60 and the main body portion 61 also become negative pressure, dust generated from the motor, belt 51, etc. will not be discharged from the electrical mounting portion 60 and the main body portion 61. In addition, by adopting a structure in which the gas discharged from the interiors of the electrical mounting portion 60 and the main body portion 61 by the fan or pump is discharged to the low-pressure area 15 disposed below the substrate transfer area 14 via a pipe or the like, dust will not adhere to the wafer W.

[0073] The aligner 8 of the present embodiment accommodates the aligner motor 46 that rotates the wafer stage 45, the aligner control unit 53, etc. inside the electrical mounting portion 60, but the present invention is not limited thereto. For example, even if a structure in which the electrical mounting portion 60 is disposed below the main body portion 61 is adopted, similarly to the first embodiment, after the wafer W is placed on the wafer stage 45, the finger portions 17a and 17b can be sufficiently moved vertically below the aligner 8.

[0074] Furthermore, the electrical mounting portion 60 can also be sufficiently disposed at a position above the area where the wafer W is placed, or disposed separately from the main body portion 61. In other words, when the wafer W is transferred between the wafer transfer robot 7 and the aligner 8, when the finger portions 17a and 17b are moved to the pre-taught positions, if the separation dimension D2 of the pair of wafer holding rods 43a and 43b is set to be larger than the width dimension D1 of the main body portion 61 of the aligner 8 through which the finger portions 17a and 17b pass in the vertical direction, the finger portions 17a and 17b will not contact the aligner 8 when descending. Furthermore, instead of the method of operating the lifting mechanism 19 of the wafer transfer robot 7 to move the finger portions 17a and 17b up and down, a lifting mechanism for moving the aligner 8 up and down can be provided to move the aligner 8 up and down relative to the finger portions 17a and 17b.

[0075] The control of the wafer transfer device 1 of the present embodiment is executed by a control PC and a drive control unit that controls the robot, aligner, load port, etc. respectively under the control of the control PC. Figure 8It is a block diagram schematically showing the structure of these control systems. The wafer transfer robot 7, aligner 8, and load port 6 included in the wafer transfer apparatus 1 are respectively provided with their own drive control units (robot control unit 32, aligner control unit 53, load port control unit 81), which receive detection signals from the detection units they respectively have and control the respective drive units in accordance with a program stored in advance. In addition, the wafer transfer apparatus 1 is provided with a control PC, which communicates with the respective drive control units 32, 53, 81 and controls the operations of the respective drive control units 32, 53, 81. The control PC includes at least a CPU for performing calculations, a communication unit for communicating with the respective control units, and a storage unit for storing operation programs and various data.

[0076] Next, the difference in the transfer operations of the wafers W1 and W2 on the arm body 18 of the aligner 8 between the wafer transfer robot 7 included in the wafer transfer apparatus 1 using the present invention and the existing wafer transfer robot 7 will be described. Figure 9 It is a diagram showing the transfer operation performed by the existing wafer transfer robot 57. Figure 10 , Figure 11 It is a diagram showing the transfer operation performed by the wafer transfer robot 7 according to an embodiment of the present invention. In the existing transfer robot, it is not considered that the lateral separation dimension D2 of the pair of wafer holding rods 43a and 43b of the upper and lower finger parts 77a and 77b included in the wafer transfer robot 57 is larger than the width dimension D1 of the main body of the aligner 58, and the following operations are usually performed.

[0077] First, the first wafer W1 is taken out from the FOUP2 placed on the load port 6 by the upper finger part 17a and placed on the wafer stage 45 of the aligners 8 and 58. Then, during the positioning of the aligners 8 and 58, the second wafer W2 is taken out and held by the lower finger part 17b for waiting. After the positioning operation of the wafer W1 is completed, the wafer W1 on the wafer stage 45 is taken out by the upper finger part 17a, and the second wafer W2 held by the lower finger part 17b is placed on the wafer stage 45. In addition, these operations are executed in accordance with the operation program stored in advance in the robot control unit 32.

[0078] Refer to Figure 9 , the operation of the existing wafer transfer robot 57 will be described. First, after moving the upper finger part 77a to the preparation position facing the FOUP2, the first wafer W1 ([[]] Figure 9is maintained as shown in (a). At this time, the wafer transfer robot 57 rotates the lower finger part 77b to a retracted position where it does not interfere with the movement of the upper finger part 77a. Next, the wafer transfer robot 57 operates the arm body 18 and the finger part 77a to take out the wafer W1 from the FOUP2 and move it above the existing aligner 58 to a given position taught in advance. After that, the wafer transfer robot 57 operates the lifting mechanism 19 to lower, and places the wafer W1 held by the upper finger part 77a on the wafer stage 45 of the aligner 58( Figure 9 as shown in (b).

[0079] When the existing aligner 58 adsorbs and holds the wafer W1 and starts the alignment operation, the wafer transfer robot 57 operates the upper finger part 77a in such a way that the arm body 18 and the upper finger part 77a do not contact the wafer stage 45 and the main body part of the aligner 58, and moves the upper finger part 77a backward horizontally with respect to the aligner 58( Figure 9 as shown in (c). At this time, the height position of the upper finger part 77a in the vertical direction is located below the wafer W1 and above the main body part of the aligner 58. Next, after the wafer transfer robot 57 rotates the lower finger part 77b in the retracted position to a ready position facing the FOUP2, it operates each drive part to hold the second wafer W2 accommodated in the FOUP2 with the lower finger part 77b( Figure 9 as shown in (d). At this time, the wafer transfer robot 57 rotates the upper finger part 77a to a retracted position where it does not interfere with the movement of the lower finger part 77b. Next, the wafer transfer robot 57 operates the arm body 18 to move the lower finger part 77b backward with respect to the FOUP2 and take out the wafer W2( Figure 9 as shown in (e).

[0080] Next, the wafer transfer robot 57 rotates the upper finger part 77a in the retracted position in the direction facing the aligner 58, and rotates the lower finger part 77b holding the wafer W2 to the retracted position( Figure 9 as shown in (f). After the operation of the aligner 58 is completed, the wafer transfer robot 57 operates the arm body 18 to move the upper finger part 77a forward to a given position directly below the first wafer W1( Figure 9 as shown in (g). During the forward movement, the height position of the upper finger part 77a in the vertical direction is below the wafer W1 and above the main body part of the aligner 58. Then, the wafer transfer robot 57 raises the lifting mechanism 19 to lift and hold the first wafer W1 whose alignment has been completed with the upper finger part 77a. Then, it rotates the lower finger part 77b to a position above the wafer stage 45 and taught in advance, and moves the upper finger part 77a to a retracted position where it does not interfere with the lower finger part 77b.

[0081] Then, the wafer transfer robot 57 operates the lifting mechanism 19 to place the wafer W2 held by the lower finger portion 77b on the wafer stage 45( Figure 9 (h) of). After that, after the wafer transfer robot 57 retracts the lower finger portion 77b relative to the aligner 58 in the horizontal plane, the wafer W1 held on the upper finger portion 77a of the wafer transfer robot 57 is transferred to a given wafer processing apparatus 3. As described above, in the case of the conventional wafer transfer robot 57 and aligner 58, when the wafer W1 or W2 is held on the aligner 58, the upper and lower finger portions 77a and 77b cannot retract from the aligner 58 unless they pass between the wafer W1 or W2 and the aligner 59 respectively. During this operation, the wafer transfer robot 57 needs to move the upper and lower finger portions 77a and 77b in a manner that does not contact the wafer stage 45, so the movements of the arm body 18 and the upper and lower finger portions 77a and 77b are precise and complex.

[0082] Next, the transfer operation of the wafer transfer robot 7 of the present embodiment will be described. Similar to the conventional wafer transfer robot 57, after the wafer transfer robot 7 rotates the upper finger portion 17a to the preparation position facing the FOUP2, the upper finger portion 17a holds the first wafer W1 accommodated in the FOUP2( Figure 10 (a) of). At this time, the wafer transfer robot 7 rotates the lower finger portion 17b to the retracted position where it does not interfere with the movement of the upper finger portion 17a. Next, the wafer transfer robot 7 operates the arm body 18 and the finger portion 17a to move the wafer W1 above the wafer stage 45 of the aligner 8 to a given position taught in advance. At this time, as Figure 10 shown, in the case where the next wafer to be taken out is the next wafer W2 coming out of the FOUP2 placed in the loading port 6' closest to the aligner 8, the wafer transfer robot 7 preferably rotates the lower finger portion 17b to the preparation position facing the FOUP2 in advance as described below.

[0083] Here, with reference to Figure 16 , the operations of the finger portions 17a and 17b and the operation control of the wafer transfer robot 7 for taking out the wafer W1 from the loading port 6'(the rightmost loading port in the present embodiment) closest to the aligner 8 and moving the wafer W1 to the taught position above the aligner 8 in the wafer transfer apparatus of the present invention will be described. In addition, the lower finger portion 17b also takes out the wafer W2 from the loading port by the same operation as the upper finger portion 17a described in the next paragraph.

[0084] When the wafer transfer robot 7 is positioned relative to the FOUP 2 pick-and-place finger portion 17a, the wafer transfer robot 7 is taught to move the finger portion 17a forward from a position orthogonal to the direction in which the front wall 11 extends and facing the FOUP 2. Here, preferably, when the wafer transfer robot 7 moves the finger portion 17a into the FOUP 2, a straight line in the horizontal plane connecting the center P1' of the wafer W1 in the case of being correctly accommodated in the FOUP 2 and the rotation axis C3 of the finger portion 17a is set as L3, which is a straight line perpendicular to the direction in which the front wall 11 extends. Next, the wafer transfer robot 7 lifts the wafer W1 in the FOUP 2 using the finger portion 17a and operates the arm body 18, thereby moving the rotation axis C3 of the finger portion 17a to the intersection point P2 of the straight line L3 and the straight line L2 passing through the rotation axis C4 of the wafer stage 45 Figure 6 as shown. After that, with the arm body 18 stopped, the wafer transfer robot 7 operates the upper finger drive motor 30 to rotate and move the upper finger portion 17a holding the wafer W1 to a given position above the wafer stage 45.

[0085] Return Figure 10 for description. When moving the wafer W1 above the base of the aligner 8, the wafer transfer robot 7 operates the lifting mechanism 19 to lower, and places the wafer W1 held by the upper finger portion 17a on the wafer stage 45 of the aligner 8 ( Figure 10 of (b)). After operating the lifting mechanism 19 to place the first wafer W1 on the wafer stage 45, the wafer transfer robot 7 continues to operate the lifting mechanism 19 to lower, and moves the upper finger portion 17a to a position below the aligner 8 where the upper finger portion 17a will not contact the aligner 8 even when it rotates.

[0086] If the upper finger portion 17a is lowered to a given position below the aligner 8, the wafer transfer robot 7 rotates the upper finger portion 17a about the rotation axis C3 to a preparation position where it coincides with the lower finger portion 17b when viewed from above, or at least to a position where it will not interfere with the upper finger portion 17a even when it rises ( Figure 10 of (c)). Next, the wafer transfer robot 7 operates the arm body 18 and the lifting mechanism 19 to move the lower finger portion 17b to a given position below the second wafer W2 accommodated in the FOUP 2, and operates the lifting mechanism 19 to hold the second wafer W2 using the lower finger portion 17b ( Figure 10 of (d)). At this time, the upper finger portion 17a rotates about the rotation axis C3 to a retracted position where it will not interfere with the movement of the lower finger portion 17b.

[0087] Next, the wafer transfer robot 7 operates the arm body 18 to move the lower finger portion 17b holding the wafer W2 backward to the preparation position ( Figure 11(e)). Then, after the wafer transfer robot 7 operates the lifting mechanism 19 to lower the upper finger portion 17a to a position below the aligner 8, the upper finger portion 17a rotates about the rotation axis C3 to a pre-taught position for holding the wafer W1. After the operation of the aligner 8 is completed, further, after the wafer transfer robot 7 moves the upper finger portion 17a to a correction position for canceling the position deviation of the wafer W1 detected by the aligner 8, the lifting mechanism 19 is operated to raise the upper finger portion 17a to a given height position above the wafer stage 45, and the upper finger portion 17a holds the wafer W1 whose alignment has been completed. Figure 11 (f)). In addition, the finger portion 17b for holding the second wafer W2 is located at a retracted position where it does not interfere with the aligner 8. Therefore, due to the upward movement of the upper finger portion 17a, the wafer W2 will not collide with the aligner 8.

[0088] Then, the wafer transfer robot 7 moves the lower finger portion 17b to a pre-taught position above the wafer stage 45, and rotates the upper finger portion 17a to a retracted position where it does not interfere with the lower finger portion 17b and the aligner 8. After that, the lifting mechanism 19 is operated to place the wafer W2 held on the lower finger portion 17b on the wafer stage 45. After the lifting mechanism 19 is operated to place the second wafer W2 on the wafer stage 45, the wafer transfer robot 7 continues the downward movement of the lifting mechanism 19 and moves the lower finger portion 17b to a given position below the aligner 8 where the lower finger portion 17b will not contact the aligner 8 even when it rotates. Figure 11 (g)). Then, the wafer transfer robot 7 rotates the lower finger portion 17b about the rotation axis C3 to a position that coincides with the upper finger portion 17a in a top view. Figure 11 Furthermore, the wafer transfer robot 7 operates the arm body 18 and the lifting mechanism 19 to transfer the wafer W1 held on the upper finger portion 17a to a given wafer processing device 3.

[0089] As described above, in the existing wafer transfer robot 57 and the wafer transfer robot 7 of the present invention, there are differences in the actions of retracting the finger portions 17a, 17b, 77a, and 77b after the wafers W1 and W2 are placed on the wafer stage 45. In the wafer transfer robot 57, it is necessary to retract the finger portions 77a and 77b horizontally with respect to the aligner 58. Therefore, the longer the lengths of the respective arms constituting the arm body 18, the longer the time taken for the operation of the arm body 18 to retract the finger portions 77a and 77b horizontally. Especially when the lengths of the respective arms 24 and 26 constituting the arm body 18 are close to the separation distance between the front wall 11 and the rear wall 12, the operating ranges of the respective arms 24 and 26 are limited so that the respective arms 24 and 26 do not contact the front wall 11 and the rear wall 12.

[0090] Therefore, the movements of the arm bodies 24 and 26 are restricted, and it takes a long time for the movements. In addition, during the retraction movements of the finger parts 77a and 77b, in order to prevent the finger parts 77a and 77b from contacting the wafer stage 45, it is necessary to maintain the postures of the finger parts 77a and 77b in synchronization with the movement of the arm body 18, and the movement control becomes more complicated. Furthermore, in the existing wafer transfer robot 57, for the retraction movement, it is necessary to switch to the retraction movement of the arm body 18 after the lowering movement of the lifting mechanism 19 is completed. Due to the existence of the switching from the lifting mechanism 19 to the movement of the arm body 18, a time lag is generated, resulting in a reduction in throughput.

[0091] The retraction movement of the wafer transfer robot 7 of the present embodiment is as Figure 12 shown. After moving the finger parts 17a and 17b to a given position above the wafer stage 45 ( Figure 12 (a)), the finger parts 17a and 17b are lowered by the lifting mechanism 19, and after the wafers W1 or W2 are placed, the lifting mechanism 19 is not stopped, and the finger part 17a or 17b is kept lowered to a position below the aligner 8 ( Figure 12 (b)). Then, after there is no risk of interference with the aligner 8, the wafers W1, and W2, the finger parts 17a and 17b are rotated ( Figure 12 (c)). Therefore, unlike the prior art, after the wafers W1 and W2 are placed on the aligner 8, it is not necessary to avoid interference with the wafers W1, W2, and the aligner 8 from the aligner approaching area and retract the finger parts 17a and 17b in such a way that the arm body 18 (arms 24 and 26) moves.

[0092] As a result, the movement time of the wafer transfer robot 7 can be shortened. Furthermore, in the retraction movement of retracting the finger parts below the aligner main body part ( Figure 12 (a) and (b)), there is no need for complicated angular displacement movements of the arms 24, 26, and the finger parts 17a, 17b, so there will be no failure of the arms 24, 26, and the finger parts 17a, 18b contacting the back wall 12 and the wafer stage 45. Here, the angular displacement movement refers to the rotational movement of the first arm 24 relative to the base 20, the rotational movement of the second arm 26 relative to the first arm 24, and the rotational movement of the finger parts 17a, 18b relative to the second arm 26. By performing this angular displacement movement, the wafer transfer robot 7 moves the finger parts 17a, 18b, and the wafers W held by the finger parts 17a, 18b to a given position.

[0093] In the aligner 8 of the present embodiment, a structure is illustrated in which the wafer stage 45 does not have a mechanism for moving in the horizontal direction. However, the wafer stage 45 may be provided with a direction parallel to the straight line L2 connecting the center P1 of the wafer W and the rotation centers of the finger portions 17a and 17b ( Figure 6 the X direction) or a direction orthogonal to the straight line L2 ( Figure 6 the Y direction) of the aligner having a moving mechanism. Furthermore, it may be configured to have a mechanism for moving in both a direction parallel to the straight line L2 (the same X direction) and a direction orthogonal to the straight line L2 (the same Y direction).

[0094] Figure 13 FIG. (a) shows a plan view of the aligner 59a having a first moving mechanism 63 for moving the wafer stage 45 in a direction parallel to the straight line L2, Figure 13 and FIG. (b) is a front view thereof. In addition, in Figures 13 to 15 , for convenience, the direction parallel to the straight line L2 is defined as the X direction, the direction orthogonal to the straight line L1 is defined as the Y direction, and the direction orthogonal to the X direction and the Y direction is defined as the Z direction (vertical direction) for explanation. The aligner 59a of the present embodiment has the same mechanism as the aligner 8, but the electrical mounting portion 60 that houses the aligner control unit 53 and the wafer detection sensor 47 is separated from the main body portion 61 that houses the driving mechanisms such as the wafer stage 45 and the aligner motor 46. In a plan view, the main body portion 61 has the same width dimension D1 as the aligner 8 of the first embodiment. The electrical mounting portion 60 is fixed to the uppermost part of the bracket 62, which is fixed to the vertical frame 5b. At the lowermost part of the bracket 62, a first moving mechanism 63 for moving the main body portion 61 including the wafer stage 45 in the X direction is mounted.

[0095] The first moving mechanism 63 is composed of a motor 64 and a ball screw mechanism. When the motor 64 operates, the ball screw connected to the rotation shaft of the motor 64 rotates, and the moving member screwed to the ball screw moves forward and backward in the X direction. The bottom surface of the main body fixing table 65 is fixed to the moving member, and the main body portion 61 is fixed to the top surface of the main body fixing table 65. In addition, the motor 64 is a motor capable of controlling the angle of the drive shaft, and the operation of the motor 64 is controlled by the aligner control unit 53. In addition, it is preferable that the electrical mounting portion 60 and the main body portion 61 are arranged in the substrate transfer area 14 above the difference pressure plate 16. Furthermore, since there is a possibility of dust generation due to the operation of the first moving mechanism 63, the first moving mechanism 63 is preferably arranged in the low-pressure area 15 below the difference pressure plate 16. As a result, the risk of dust generated by the first moving mechanism 63 adhering to the wafer W is reduced.

[0096] By adopting the above structure, the wafer inspection sensor 47 is used to detect the rotational offset of the notch of the wafer W and the position offset in the X-Y direction of the center of the wafer W, and calculate the position offset in the X-Y direction of the wafer W when the notch is moved to a given rotational position pre-taught for the position of the notch and the correction data for correcting the position offset in the X-Y direction. Then, the aligner 59a rotates the wafer W until the notch reaches a given rotational position pre-taught on the periphery of the wafer W to correct the rotational offset. Furthermore, for the position offset in the X direction of the wafer W, the first moving mechanism 63 is used to move the wafer stage 45 and the wafer W, thereby being able to correct the position offset in the X direction.

[0097] In addition, after the aligner 59a corrects the wafer W in the X direction, when the finger parts 17a and 17b move to the position for correcting the position offset in the Y direction, the wafer W is lifted from below, thereby being able to hold the wafer W at the position where the position offsets in the X direction and the Y direction of the wafer W are corrected. Moreover, when performing the correction of moving the finger parts in the Y direction, by making the gap ((D2 - D1) / 2) larger than the maximum allowable correction amount in the Y direction in advance, the finger parts 17a and 17b for placing the wafer W on the wafer stage 45 can move to the lower part of the main body part 61 without changing the horizontal posture, so that the handling throughput of the wafer W can be improved.

[0098] Figure 14 FIG. (a) shows an aligner 59b having a second moving mechanism 67 below the first moving mechanism 63 for moving the first moving mechanism 63 forward and backward in the Y direction. Figure 14 FIG. (b) is a front view thereof. The second moving mechanism 67 has the same structure as the first moving mechanism 63 and is installed at the lowermost part of the bracket 62a. The second moving mechanism 67 is composed of a motor 66 and a ball screw mechanism. When the motor 66 operates, the ball screw connected to the rotation shaft 48 of the motor rotates, and the moving member screwed with the ball screw moves forward and backward in the Y direction. The first moving mechanism 63 is fixed to the moving member. The motor 66 is a motor capable of angle control, and the operation of the motor 66 is controlled by the aligner control unit 53.

[0099] By setting the above structure, the wafer detection sensor 47 detects the position of the notch of the wafer W and the offset of the center of the wafer W, and calculates the position offset of the wafer W in the XY direction when the position of the notch is taught in advance and the given rotation position is moved, and the correction data for correcting the position offset in the XY direction is calculated. By rotating the wafer base 45, the position of the notch is positioned at the given rotation position taught in advance, and then, the position offset of the wafer W in the X direction and the Y direction can be corrected by operating the first moving mechanism 63 and the second moving mechanism 67. In addition, similarly to the aligners 8 and 59a of the first and second embodiments, the fingers 17a and 17b that place the wafer W on the wafer base 45 can be moved to the bottom of the main body 61 without changing the horizontal posture, so the handling throughput of the wafer W can be improved. In addition, since there is a possibility that dust is caused to the wafer W by the operation of the second moving mechanism 67, it is preferred that the second moving mechanism 67 is arranged in the low pressure area 15 below the differential pressure plate 16, similarly to the first moving mechanism 63.

[0100] Furthermore, the electrical installation part 60 and the main body 61 may be integrated, and the electrical installation part 60 and the main body 61 may be moved in an integrated manner in the X direction and the Y direction by using the first moving mechanism 63 and the second moving mechanism 67. By setting the above structure, the same effect as the aligner 59a of the second embodiment and the aligner 59b of the third embodiment can be achieved. However, when the wafer base 45 is moved to correct the positional deviation of the wafer W, when the next wafer W is placed on the wafer base 45, it is necessary to operate the first moving mechanism 63 and the second moving mechanism 67 to move the wafer base 45 to a predetermined given position.

[0101] The transport operation performed by the wafer transport robot 7 and the aligner 8 of this embodiment is not limited to the suction-type fingers 17 a and 17 b that hold the wafer W by vacuum suction force, and so-called clamp-type fingers 68 that hold the wafer W by gripping the periphery of the wafer W may also be applied. Figure 15 : is a top view showing a clamping finger 68 and a clamping aligner 69 as another embodiment of the present invention. The clamping finger 68 of this embodiment is composed of a holding portion 78 for holding a wafer W and a wrist portion 79 for supporting the base end of the holding portion 78. The base end of the wrist portion 79 is rotatably mounted on the front end of the second arm 26 with the rotation axis C3 as the rotation center, and is rotated by the finger driving motor 30 provided in the second arm 26. The holding portion 78 for holding the wafer W includes: a pair of wafer holding rods 70 and 71 arranged in parallel; and a clamping member 72 for mechanically holding the wafer W by pressing the periphery of the wafer W toward the locking portion 75 at the front end of the holding rods 70 and 71 by the action of a spring.

[0102] In addition, the clamping aligner 69 of the present embodiment includes: clamping rods 73a, 73b, and 73c that mechanically hold the periphery of the wafer W by the action of a spring or the like; and a wafer base 74 that rotates in a horizontal plane about a straight line C5 (hereinafter referred to as "rotation axis C5") extending in the vertical direction of the paper surface of Figure 15 When the wafer transfer robot 7 exchanges the wafer W with the clamping aligner 69, the clamping finger portion 68 is moved to a position where the center P1 of the wafer W held by operating the arm body 18 coincides with the rotation axis C5 of the wafer base 74 of the clamping aligner 69.

[0103] A pair of wafer holding rods 70 and 71 provided in the holding portion 78 of the clamping finger portion 68 are fixed to the wrist portion 79 so as to be line-symmetrical with respect to a straight line L4 extending in a horizontal plane connecting the rotation axis C3 of the clamping finger portion 68 and the rotation axis C5 of the wafer base 74 in a plan view. In addition, at the front end of each of the wafer holding rods 70 and 71, there is provided a locking member 75 that locks the peripheral portion of the wafer W pressed by the clamping member 72. The clamping member 72 is formed in a Y shape with a bifurcated front end in a plan view, and at the front end of each of the bifurcated portions, there is provided a clamping pad 76 that contacts the peripheral portion of the wafer W. The clamping member 72 includes a biasing member and an actuator that drives the clamping member 72 in a direction approaching or away from the wafer W within the wrist portion 79. When the clamping member 72 is moved in a direction approaching the wafer by the actuator, it is pushed out toward the wafer W by the action of the biasing member to hold the wafer W. In addition, by operating the clamping member 72 in a direction away from the wafer W by the actuator, the clamping member 72 is retracted with respect to the wafer W to release the holding of the wafer W.

[0104] Regarding the mechanism for holding the wafer W in the chuck aligner 69 of the present embodiment and the mechanism for rotating the held wafer W, a mechanism of a known technique can be used. Three clamping rods 73a, 73b, and 73c having equal lengths are radially arranged with the rotation axis C5 as the starting point on the wafer base 74, and a locking member 80 for locking the wafer W is provided at each front end of the clamping rods 73a, 73b, and 73c. In addition, the clamping rods 73a, 73b, and 73c have a telescopic mechanism. When receiving the wafer W from the clamping fingers 68, each of the clamping rods 73a, 73b, and 73c extends, and when holding the wafer W, the three clamping rods 73a, 73b, and 73c respectively contract, thereby holding the peripheral portion of the wafer W by the respective locking members 80. Furthermore, the chuck aligner 69 is provided with a wafer detection sensor 47, and rotates the held wafer W in the horizontal plane to detect the positions of the notch and the orientation flat formed in the peripheral portion of the wafer W by the wafer detection sensor 47. In addition, the chuck aligner 69 of the present embodiment is configured to hold the peripheral portion of the wafer W with an equal holding force by the three clamping rods 73a, 73b, and 73c. Therefore, the center P1 at the taught position of the held wafer W coincides with the rotation axis C5 of the wafer base 74 when viewed from above.

[0105] When the chuck aligner 69 of the present embodiment is arranged at the standby position for receiving the wafer W from the clamping fingers 68, the locking member 80 fixed to the front end of the first clamping rod 73a is located between the two clamping pads 76 at the bifurcated front ends of the clamping members 72 provided in the clamping fingers 68, and is in a position where it does not interfere with the two clamping pads 76. In addition, the second clamping rod 73b and the third clamping rod 73c are arranged in a position where they do not contact the pair of wafer holding rods 70 and 71 of the clamping fingers 68, and are arranged symmetrically when viewed from above with respect to the straight line L4. In addition, the respective clamping rods 73a, 73b, and 73c provided in the chuck aligner 69 of the present embodiment are not arranged at equal angles. For example, the angle formed by the first clamping rod 73a and the second clamping rod 73b is 150°, the angle formed by the second clamping rod 73b and the third clamping rod 73c is 60°, and the angle between the third clamping rod 73c and the first clamping rod 73a is 150°. In addition, the angles formed by the respective clamping rods 73a, 73b, and 73c are not limited to this. In addition, the number of the clamping rods 73a, 73b, and 73c is not limited to three. For example, the clamping rods 73a, 73b, and 73c may be three or more, or the clamping rods 73a, 73b, and 73c may be two, and three or more locking members 80 for holding the wafer W may be provided.

[0106] In addition, the separation distance D4 between the left and right wafer holding rods 70 and 71 provided in the clamping finger portion 68 of the present embodiment is formed to be larger than the dimension D3 in the width direction, which is the direction orthogonal to the straight line L3, of the wafer base 74 of the clamping aligner 69 and the clamping aligner 69 main body. According to the above structure, after the wafer W is transferred to the clamping aligner 69, the clamping finger portion 68 can move downward in the vertical direction to the lower side of the clamping aligner 69.

[0107] As described above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. For example, in the above embodiment, the case of transferring the wafer W from the FOUP 2 to the wafer processing apparatus 3 via the aligner 8 has been described, but it can also be applied to the case of transferring the FOUP 2 from the wafer processing apparatus 3 via the aligner 8. Further, in addition to the function of detecting the position deviation and notch of the wafer W, the aligner 8 may adopt a structure having various other inspection functions such as various functions, for example, a function of reading the wafer ID engraved on the wafer W.

Claims

1. A wafer transfer device, comprising: an aligner that holds a wafer on a wafer base and detects a peripheral portion of the wafer; and a transfer robot that holds the wafer and transfers the wafer between a loading port, the aligner, and a processing device. The transfer robot includes: An arm body having at least two arms, with one end of each arm connected in a rotatable manner to each other; Finger portions rotatably mounted at the front end of the arm body and holding the wafer using a pair of wafer holding rods; An arm body drive mechanism that moves the arm body; A finger portion drive mechanism that drives the finger portions to rotate in a horizontal plane; And A lifting mechanism that moves the arm body in a vertical direction. The wafer base is rotatably supported by an aligner main body portion, and the aligner main body portion is fixed by a bracket and horizontally held. The aligner main body portion has a base member, the wafer base, and a driven pulley. The base member is horizontally supported by a bracket. The wafer base is fixed to the upper portion of a cylindrical shaft rotatably mounted to the base member via a bearing. The driven pulley is rotatably provided at the lower end of the shaft. The widthwise dimension of the aligner main body portion in the area accessed by the finger portions is smaller than the separation dimension of the pair of wafer holding rods. After placing the wafer held by the finger portions on the wafer base by lowering the finger portions using the lifting mechanism, the finger portions are further lowered to a position below the main body portion of the aligner, and then the arm body is driven to move the finger portions to the next transfer operation.

2. The wafer transfer device according to claim 1, wherein The difference between the separation dimension of the pair of wafer holding rods and the dimension of the aligner main body portion is greater than the allowable offset dimension of the wafer.

3. The wafer transfer device according to claim 1 or 2, wherein The aligner is provided with an exhaust unit that discharges the air inside the aligner to the outside.

4. The wafer transfer device according to claim 1 or 2, wherein The wafer base is a suction-type wafer base that suction-holds the wafer, and the finger portions are suction-type finger portions that suction-hold the wafer.

5. The wafer transfer device according to claim 1 or 2, wherein The wafer base is a clamp-type wafer base that clamps the peripheral portion of the wafer, and the finger portions are clamp-type finger portions that clamp the peripheral portion of the wafer.

6. The wafer transfer device according to claim 4, wherein A pair of wafer holding pads and wafer contact portions for sucking the wafer are arranged on the suction-type finger portions. When viewed from above the center of the wafer held by the suction-type finger portions, it is arranged in a triangle formed by connecting the pair of wafer holding pads and the wafer contact portions. When the suction-type finger portions are at a position where the wafer is transferred between the suction-type finger portions and the suction-type wafer base, the rotation center axis of the suction-type wafer base is arranged in the triangle when viewed from above.

7. The wafer transfer device according to claim 4, wherein The aligner is provided with a moving mechanism that moves the suction-type wafer base in a horizontal plane.

8. A wafer transfer method for a wafer transfer robot, which is a transfer method for the wafer transfer robot to transfer wafers between the wafer transfer robot and the aligner in a wafer transfer device equipped with an aligner and a wafer transfer robot. The aligner holds the wafer on a wafer base and detects the peripheral portion of the wafer. The wafer transfer robot has finger portions and an arm body, and holds the wafer on the finger portions and transfers it between a loading port, the aligner, and a processing device. The finger portions include a pair of wafer holding rods. The aligner has an aligner main body portion, and the aligner main body portion is horizontally held by a bracket and supports the wafer base in a rotatable manner. In the access area of the finger portions, the width of the aligner main body portion is smaller than the separation dimension of the pair of wafer holding rods. The aligner main body portion has a base member, the wafer base, and a driven pulley. The base member is horizontally supported by a bracket. The wafer base is fixed to the upper part of a cylindrical shaft that is rotatably mounted on the base member via a bearing. The driven pulley is rotatably provided at the lower end of the shaft. The wafer transfer method includes: A placement step of lowering the finger portions from above the aligner for the wafer held on the finger portions, thereby placing the wafer on the wafer base; And A retraction step of driving the arm body to transfer the finger portions to the next transfer operation after further lowering the finger portions and moving them below the aligner main body portion.

9. The wafer transfer method for a wafer transfer robot according to claim 8, wherein The wafer transfer method further includes: A detection step of detecting the position offset of the wafer by the aligner detecting the peripheral portion of the wafer held on the wafer base after the placement step; and A holding step of raising the finger portions retracted by the retraction step above the wafer base after the detection step, thereby holding the wafer placed on the wafer base.

10. The wafer transfer method for a wafer transfer robot according to claim 9, wherein The wafer transfer method further includes: a rotation offset correction step of the aligner moving the finger portions in the horizontal direction to a direction that cancels the rotation offset of the wafer detected by the aligner before the holding step.

11. The wafer transfer method for a wafer transfer robot according to claim 9 or 10, wherein The wafer transfer method further includes: a position offset correction step of the wafer transfer robot moving the finger portions in the horizontal direction to a direction that cancels the position offset of the wafer detected by the aligner before the holding step.

12. The wafer transfer method for a wafer transfer robot according to claim 9 or 10, wherein The wafer transfer method further includes: a position offset correction step of the aligner moving the wafer base in the horizontal plane to a direction that cancels the detected position offset of the wafer before the holding step.

Images