Robotic system and displacement acquisition method

Abstract

A robot system includes: a robot; a wafer jig held by the robot; a positioning stage capable of placing the wafer jig; a position offset detection device capable of detecting position offset of the wafer jig; a control unit that issues commands to the robot for control; and a displacement acquisition unit that acquires the displacement generated between a commanded position and an actual position. The positioning stage has a contact member. A conical surface is formed on the wafer jig. The conical surface guides the wafer jig in such a way that as the position of contact between the conical surface and the contact member increases relatively, the center of the wafer jig approaches a predetermined position. After placing the wafer jig on the positioning stage, the robot holds the wafer jig and transports it to the position offset detection device. The displacement acquisition unit acquires the displacement based on the position offset detected by the position offset detection device.

Description

Technical Field

[0001] This disclosure relates to the acquisition of a displacement (offset) generated between a commanded position for a robot and the actual position of the robot achieved by the commanded position. Background Technology

[0002] Previously, a robot system was known to be configured in a cleanroom for manufacturing semiconductor wafers (semiconductor substrates) and to automatically teach the robot that transports the semiconductor wafers the transport position. Patent Document 1 discloses such a robot system.

[0003] The robot system of Patent Document 1 includes a robot, two or more reference components, a posture detector, and a control device. The two or more reference components are arranged around a reference position. Each reference component has a first portion that increases in size as its horizontal cross-section faces downwards. When a workpiece is correctly transported to the reference position, the distance between the outer periphery of the workpiece and the base end of the first portion of the reference component becomes a predetermined first threshold. The robot lowers the workpiece toward the reference position while holding it in place. At this time, the robot's control loop gain is, for example, zero. The horizontal movement direction of the robot caused by the workpiece contacting the first portion is calculated based on the robot's posture information detected by the posture detector. The reference position is corrected by adding the first threshold relative to the calculated movement direction.

[0004] [Existing technical documents]

[0005] [Patent Literature]

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-087980 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, the inventors in this case discovered a robot system and displacement acquisition method suitable for automatic teaching, which are different from the automatic teaching system disclosed in Patent Document 1.

[0009] In view of this, the purpose of this disclosure is to provide a robot system suitable for automatic teaching and a method for obtaining displacement.

[0010] Technical solutions used to solve the problem

[0011] The problem that this disclosure seeks to solve has been explained above. The means used to solve the problem and their effectiveness are described below.

[0012] According to a first aspect of this disclosure, a robot system with the following structure is provided. That is, the robot system includes a robot, a wafer jig, a positioning stage, a position offset detection device, a control unit, and a displacement acquisition unit. The robot is capable of holding a wafer via a holding part. The wafer jig is held by the robot. The wafer jig can be placed on the positioning stage. The position offset detection device is disposed at a different position from the positioning stage. The position offset detection device is capable of detecting the position offset of the wafer jig relative to a detection reference position. The control unit issues commands to control the robot. The displacement acquisition unit acquires the displacement (offset) generated between the commanded position and the actual position of the robot. The positioning stage has a contact member. The contact member can contact the wafer jig. A conical surface is formed on the wafer jig. The conical surface guides the wafer jig in such a way that as the position of contact between the conical surface and the contact member increases relatively, the center of the wafer jig approaches a predetermined position. According to commands from the control unit, after placing the wafer jig on the positioning stage, the robot holds the wafer jig and transports it to the position offset detection device. The displacement acquisition unit acquires the displacement based on the position offset detected by the position offset detection device of the transported wafer fixture.

[0013] In this configuration, when the wafer jig is placed on the positioning stage, it is positioned using a conical surface. The robot then holds the wafer jig positioned on the stage. If the actual position of the holding part deviates when the wafer jig is to be held, this deviation is detected as a positional deviation of the wafer jig by the position deviation detection device. Therefore, the displacement generated between the commanded position and the actual position of the robot can be easily detected by the position deviation detection device. In this way, the displacement required to correct the commanded position for improving the robot's motion accuracy can be automatically obtained via the wafer jig and the position deviation detection device. Therefore, significant effort reduction is achieved.

[0014] According to a second aspect of this disclosure, a displacement acquisition method is provided. Specifically, this displacement acquisition method acquires the displacement generated between a commanded position and an actual position of the robot in a robot system, the robot system including a robot, a wafer jig, a positioning stage, a position offset detection device, and a control unit. The robot is capable of holding a wafer via a holding part. The wafer jig is held by the robot. The wafer jig can be placed on the positioning stage. The position offset detection device is disposed at a different position from the positioning stage. The position offset detection device is capable of detecting the position offset of the wafer jig relative to a detection reference position. The control unit issues commands to control the robot. The positioning stage has a contact member capable of contacting the wafer jig. A conical surface is formed on the wafer jig. The conical surface guides the wafer jig in such a way that as the position of the conical surface in contact with the contact member relatively increases, the center of the wafer jig approaches a predetermined position. The method includes a first step, a second step, and a third step. In the first step, the control unit issues a command to the robot to place the wafer jig on the positioning stage. In the second step, the control unit issues commands to the robot to hold the wafer jig and move it to the position offset detection device. In the third step, the displacement is obtained based on the position offset detected by the position offset detection device of the moved wafer jig.

[0015] In this method, when the wafer jig is placed on the positioning stage, it is positioned using a conical surface. The robot then holds the wafer jig positioned on the stage. If the actual position of the holding part deviates when the wafer jig is to be held, this deviation is detected as a positional deviation of the wafer jig by the position deviation detection device. Therefore, the displacement generated between the commanded position and the actual position of the robot can be easily detected by the position deviation detection device. In this way, the displacement required to correct the commanded position for improving the robot's motion accuracy can be automatically obtained via the wafer jig and the position deviation detection device. This significantly reduces labor intensity.

[0016] The benefits of invention

[0017] According to this disclosure, a robot system suitable for automatic teaching and a method for obtaining displacement can be provided. Attached Figure Description

[0018] Figure 1 This is a perspective view showing the structure of a robot system according to an embodiment of the present disclosure;

[0019] Figure 2 It is a 3D diagram showing the structure of the robot;

[0020] Figure 3It is a three-dimensional view showing the structure of the wafer fixture;

[0021] Figure 4 This is a side view showing the structure of the wafer fixture;

[0022] Figure 5 It is a three-dimensional view showing the structure of the contact components;

[0023] Figure 6 It is a side cross-sectional view showing the wafer fixture and contact components;

[0024] Figure 7 It is a block diagram showing a portion of the structure of a robot system; and

[0025] Figure 8 This is a diagram showing a modified example of a wafer fixture.

[0026] Explanation of reference numerals in the attached figures Detailed Implementation

[0027] The embodiments of this disclosure will now be described with reference to the accompanying drawings. Figure 1 This is a perspective view showing the structure of a robot system 100 according to one embodiment of the present disclosure. Figure 2 This is a 3D diagram showing the structure of robot 1. Figure 3 This is a three-dimensional view showing the structure of wafer fixture 2. Figure 4 This is a side view showing the structure of wafer fixture 2. Figure 5 This is a perspective view showing the structure of the contact component 31. Figure 6 This is a side cross-sectional view showing the wafer fixture 2 and the contact component 31. Figure 7 This is a block diagram showing a portion of the structure of the robot system 100.

[0028] Figure 1 The robot system 100 shown is a system that enables the robot 1 to work in a cleanroom or other workspace.

[0029] The robot system 100 includes a robot 1, a wafer fixture 2, a positioning stage 3, a position offset detection device 4, and a controller 5.

[0030] Robot 1, for example, functions as a wafer transfer robot used to transport and store wafers 20 in storage device 6. In this embodiment, robot 1 is implemented as a SCARA-type horizontal articulated robot. SCARA is an abbreviation for Selective Compliance Assembly Robot Arm.

[0031] like Figure 2 As shown, robot 1 includes a hand (holding part) 10, a robotic arm 11, and a posture detection part 12.

[0032] The hand 10 is a type of end effector, typically appearing as a V or U shape when viewed from above. The hand 10 is supported at the front end of the robotic arm 11 (specifically, the second link 16 described later). The hand 10 rotates relative to the second link 16, with a third axis c3 extending vertically as its center.

[0033] The robotic arm 11 mainly includes a base 13, a lifting shaft 14, and multiple links (here, the first link 15 and the second link 16).

[0034] The base 13 is fixed to the ground (e.g., the floor of a cleanroom). The base 13 functions as a base component supporting the lifting shaft 14.

[0035] The lifting shaft 14 moves relative to the base 13 in the vertical direction. By lifting it, the height of the first link 15, the second link 16, and the hand 10 can be changed.

[0036] The first link 15 is supported on the upper part of the lifting shaft 14. The first link 15 rotates relative to the lifting shaft 14 about a first axis c1 extending in the vertical direction. As a result, the posture of the first link 15 can be changed in the horizontal plane.

[0037] The second link 16 is supported at the front end of the first link 15. The second link 16 rotates relative to the first link 15 about a second axis c2 extending in the vertical direction. Thus, the posture of the second link 16 can be changed in the horizontal plane.

[0038] The posture detection unit 12 has multiple rotation sensors 12a. The rotation sensors 12a are, for example, encoders. Each rotation sensor 12a detects each rotational position of the drive motor (not shown) driving the hand 10, the first link 15, and the second link 16. Each rotation sensor 12a is electrically connected to the controller 5 and transmits the detected rotational position to the controller 5.

[0039] The wafer fixture 2 is a fixture that simulates the wafer 20, and is generally formed in the shape of a circular plate. The wafer fixture 2 is thicker than the wafer 20. As a result, the conical surface 23, which will be described later, can be easily formed on the wafer fixture 2.

[0040] like Figure 3 as well as Figure 4 As shown, the wafer jig 2 has a positioning body 21a and a flange portion 21b. The positioning body 21a and the flange portion 21b are integrally formed.

[0041] The wafer jig 2 is typically used with the positioning body 21a protruding downward from the flange portion 21b. Therefore, the protruding end face of the flange portion 21b can be considered as the lower surface 22 of the wafer jig 2.

[0042] The flange portion 21b is formed in the shape of a circular plate. The flange portion 21b is disposed on the outer periphery of the positioning body 21a. The diameter of the flange portion 21b is equal to the diameter of the wafer 20, which is the object to be transported by the robot 1. The center of the flange portion 21b is aligned with the central axis 2c of the wafer fixture 2. The flange portion 21b is arranged perpendicular to the central axis 2c.

[0043] The bottom part 22 is formed as a circular planar shape. The diameter of the bottom part 22 is smaller than the diameter of the flange 21b. The center of the bottom part 22 is aligned with the central axis 2c of the wafer jig 2. The bottom part 22 is arranged perpendicular to the central axis 2c.

[0044] A conical surface 23 is formed on the outer periphery of the positioning body 21a. With the wafer jig 2 in a horizontal orientation, the conical surface 23 is positioned in the height direction between the flange 21b and the lower surface 22. The conical surface 23 is formed as a cone shape whose diameter decreases as it moves away from the flange 21b (closer to the lower surface 22). The diameter of the portion of the conical surface 23 closest to the flange 21b is slightly smaller than the diameter of the flange 21b.

[0045] The positioning body 21a is configured as a thin, inverted frustum-shaped structure by having the lower part 22 and the conical surface 23 as described above.

[0046] The positioning stage 3 is used to position the wafer jig 2 at a pre-set reference position.

[0047] like Figure 1 As shown, the positioning stage 3 has a pair of contact members 31 for embedding the wafer jig 2. The two contact members 31 are identical in shape. The two contact members 31 constitute a worktable for setting the wafer jig 2.

[0048] like Figure 5 As shown, the contact component 31 is formed in an arc shape when viewed from above.

[0049] like Figure 5 As shown in Figure 6, each contact member 31 is formed in a stepped shape. A horizontal support surface 31a is formed on the stepped portion. The flange portion 21b can be supported on the support surface 31a. Since the support surfaces 31a of the two contact members 31 are at the same height, the wafer jig 2 straddling the two support surfaces 31a is horizontal.

[0050] An arc-shaped limiting surface 31b is formed on the inner peripheral surface of the contact member 31. The limiting surface 31b is positioned below the support surface 31a. The limiting surface 31b is perpendicular to the support surface 31a. A pair of contact members 31 are arranged such that the arc centers of the limiting surfaces 31b coincide. Figure 5 In the diagram, the center of the arc is indicated by the number 31c. It can also be considered that the center of the arc 31c is the center 3c of the positioning stage 3.

[0051] Therefore, even if there is a slight offset in the top view when the wafer jig 2 is placed between the two contact parts 31, as long as the wafer jig 2 is released from holding with a gap in the vertical direction between the support surface 31a and the flange 21b, the wafer jig 2 can still be guided by the conical surface 23 and the limiting surface 31b during the process of falling by its own weight.

[0052] The details are as follows. Assume that the conical surface 23 of the wafer jig 2 contacts the contact member 31 (specifically, at the boundary between the limiting surface 31b and the supporting surface 31a). As described above, the conical surface 23 is formed such that its diameter decreases as it moves downwards. Due to this conical shape, if the wafer jig 2 attempts to descend using its own weight, the conical surface 23 is pushed by the contact member 31 as the contact position with the contact member 31 becomes relatively higher. Consequently, in a top view, the central axis 2c of the wafer jig 2 approaches the arc center 31c, which serves as the center 3c of the positioning stage 3.

[0053] The diameter of the arcuate portion of the limiting surface 31b is the same as the diameter of the portion of the conical surface 23 of the wafer jig 2 closest to the flange 21b. Therefore, when the flange 21b of the wafer jig 2 is in contact with the support surface 31a, the central axis 2c of the wafer jig 2 can be aligned with the arcuate center 31c of the limiting surface 31b. This arcuate center 31c can also be referred to as the positioning target, i.e., the predetermined position.

[0054] In this way, the wafer jig 2 can be positioned from a top view. Also, depending on the degree of positioning error that can be tolerated from a top view, the diameter of the arc of the limiting surface 31b can be set to be larger than the diameter of the part of the cone surface 23 of the wafer jig 2 that is closest to the flange 21b.

[0055] The positioning of the wafer jig 2 in the height direction is achieved by the flange 21b contacting the support surface 31a.

[0056] The position offset detection device 4 may be composed, for example, of a pre-aligner (wafer aligner). Figure 1 As shown, the position offset detection device 4 includes a rotary table 41 and a linear sensor 42. Initially, the pre-aligner was used on the wafer 20, but in this embodiment, the pre-aligner can also be used for position offset detection of the wafer jig 2.

[0057] The rotary table 41 can rotate the wafer jig 2 (wafer 20) using an electric motor (not shown in the diagram). The rotary table 41 rotates with the wafer jig 2 (wafer 20) placed on it. Figure 1 As shown, the rotating platform 41 is, for example, formed in a cylindrical shape. However, it is not limited to this.

[0058] The linear sensor 42 is, for example, a transmissive sensor having a light-emitting portion and a light-receiving portion. The light-emitting portion and the light-receiving portion are positioned opposite each other and spaced at a predetermined interval in the vertical direction. The linear sensor 42 projects detection light through the light-emitting portion arranged radially on the rotary table 41, and receives the detection light through the light-receiving portion provided below the light-emitting portion. The detection light can be, for example, a laser. If the wafer jig 2 (wafer 20) is placed on the rotary table 41, its outer edge is located between the light-emitting portion and the light-receiving portion.

[0059] Linear sensor 42 is electrically connected to displacement acquisition unit 51, which will be described later. Linear sensor 42 transmits the detection result of the light-receiving part to displacement acquisition unit 51. Details will be described later, but the change in the detection result of the light-receiving part when the rotary table 41 is rotated corresponds to the outer edge shape of the wafer jig 2 (wafer 20). Based on the shape of its outer edge, the positional offset of the center of the wafer jig 2 (wafer 20) from the rotation center of the rotary table 41 can be detected. Therefore, in the position offset detection device 4, the detection reference position of the position offset is the rotation center of the rotary table 41. Displacement acquisition unit 51 acquires the displacement amount of wafer jig 2 (wafer 20) based on the detection result of the light-receiving part.

[0060] The linear sensor 42 is not limited to a transmissive sensor; for example, it can also be composed of a reflective sensor.

[0061] like Figure 7 As shown, the controller 5 includes a displacement acquisition unit 51 and a control unit 52. The controller 5 is configured as a known computer with a CPU, ROM, RAM, and auxiliary storage device. The auxiliary storage device is configured as, for example, an HDD or SSD. The auxiliary storage device stores robot control programs and the like for implementing the displacement acquisition method of this disclosure. Through the coordinated operation of the hardware and software, the controller 5 can operate as the displacement acquisition unit 51 and the control unit 52.

[0062] As described above, the displacement acquisition unit 51 acquires the displacement of the wafer 20 (i.e., the wafer fixture 2) based on the detection result from the linear sensor 42.

[0063] The control unit 52 controls the output command values ​​of each drive motor that drives each part of the robot 1 according to the preset action program or the movement command input by the user, so that the hand 10 moves to the preset command position.

[0064] Next, a method for obtaining displacement in the robot system 100 of this embodiment will be described in detail. This displacement is necessary for correcting the command position of the robot 1.

[0065] When not in use, wafer fixture 2 is as follows Figure 1The wafer jig 2 is stored in a suitable storage location 7. According to the control instructions from the control unit 52, the robot 1 holds the wafer jig 2 in storage location 7 and moves it directly above the positioning stage 3.

[0066] When the wafer jig 2 is positioned directly above the positioning stage 3, the control unit 52 controls the robot 1 in such a way that the wafer jig 2 is positioned between a pair of contact parts 31 of the positioning stage 3.

[0067] If the robot 1 releases its grip on the wafer jig 2, the wafer jig 2 is placed on the positioning stage 3. Even if the center 3c of the positioning stage 3 is not aligned with the central axis 2c of the wafer jig 2, the wafer jig 2 still moves with its central axis 2c aligned with the center 3c of the positioning stage 3, guided by the conical surface 23 and the limiting surface 31b. As a result, the wafer jig 2 is physically and correctly positioned by the positioning stage 3.

[0068] Then, the control unit 52 controls the robot 1 to hold the wafer jig 2 placed on the positioning stage 3 at a preset commanded position. This commanded position is usually defined as the position where the center of the hand 10 coincides with the center 3c of the positioning stage 3. However, due to tolerances of the robot 1, an offset may occur between this commanded position and the actual position. Due to this offset, the wafer jig 2 is held with its center offset relative to the center of the hand 10. Hereinafter, this offset is sometimes referred to as the holding offset.

[0069] The control unit 52 further controls the robot 1 to transport the held wafer jig 2 to the rotary table 41 of the position offset detection device 4. The commanded position at this time is defined as the position where the center of the hand 10 coincides with the rotation center of the rotary table 41. The positional relationship between the center 3c of the positioning stage 3 and the rotation center of the rotary table 41 is accurately determined in advance, and the robot 1 is taught a transport command based on this positional relationship. Therefore, the holding offset of the robot 1 when holding the wafer jig 2 on the positioning stage 3 is expressed as the offset between the central axis 2c of the wafer jig 2 placed on the rotary table 41 and the rotation center of the rotary table 41.

[0070] The position offset detection device 4 rotates the rotary table 41 while continuously detecting the peripheral position of the wafer jig 2 using a linear sensor 42. When the central axis 2c of the wafer jig 2 is perfectly aligned with the rotation center of the rotary table 41, the peripheral position of the wafer jig 2 detected by the linear sensor 42 remains constant regardless of the rotation phase of the rotary table 41. When the center of the wafer jig 2 is offset from the center of the rotary table 41, the peripheral position of the wafer jig 2 is linked to the rotation of the rotary table 41, changing the amplitude according to the offset distance. Furthermore, the direction of the offset can be obtained, for example, based on the phase of the rotary table 41 when the peripheral position is at its maximum or minimum.

[0071] The displacement acquisition unit 51 acquires the offset based on the detection result of the linear sensor 42. The offset indicates the direction and distance by which the central axis 2c of the wafer fixture 2 has shifted relative to the rotation center of the rotary table 41. The offset can be displayed, for example, as a planar vector (ox, oy). Since the calculation method is well-known, it is omitted, but this offset can be obtained by performing well-known geometric calculations. This offset is consistent with the displacement amount that maintains the offset. Therefore, the displacement amount can be obtained by acquiring the offset.

[0072] The displacement acquisition unit 51 transmits the acquired displacement amount to the control unit 52. The control unit 52 corrects the command position of the hand unit 10 from a top-down view based on the displacement amount received from the displacement acquisition unit 51. The corrected command position can be obtained by subtracting the displacement amount vector from the original command position. That is, (corrected command position) = (command position) - (displacement amount). By assigning the corrected command position to the robot 1 through the controller 5, the motion accuracy of the robot 1 can be improved.

[0073] The sequence of operations—(1) moving the wafer jig 2 from its self-holding position 7 to the positioning stage 3, (2) moving the wafer jig 2 from the positioning stage 3 to the position offset detection device 4, (3) acquiring the position offset of the wafer jig 2 from the position offset detection device 4, (4) acquiring the displacement, and (5) moving the wafer jig 2 from the position offset detection device 4 to the holding position 7—is stored as a program in the controller 5. Thus, using the wafer jig 2 and the position offset detection device 4, a series of operations to acquire the displacement and correct the command position can be performed completely automatically.

[0074] As described above, the robot system 100 of this embodiment includes a robot 1, a wafer jig 2, a positioning stage 3, a position offset detection device 4, a control unit 52, and a displacement acquisition unit 51. The robot 1 can hold a wafer 20 using its hand 10. The wafer jig 2 is held by the robot 1. The wafer jig 2 can be placed on the positioning stage 3. The position offset detection device 4 is positioned at a different location from the positioning stage 3. The position offset detection device 4 can detect the position offset of the wafer jig 2 relative to the rotation center of the rotary table 41. The control unit 52 issues commands to the robot 1 for control. The displacement acquisition unit 51 acquires the displacement generated between the commanded position and the actual position of the robot 1. The positioning stage 3 has a contact member 31. The contact member 31 can contact the wafer jig 2. A conical surface 23 is formed on the wafer jig 2. As the position of the conical surface 23 in contact with the contact member 31 increases, the wafer jig 2 is guided so that its center approaches a predetermined position (the center 3c of the positioning stage 3). Following instructions from the control unit 52, robot 1 places wafer jig 2 on the positioning stage 3, holds the wafer jig 2, and transports it to the position offset detection device 4. The displacement acquisition unit 51 acquires the displacement based on the position offset detected by the position offset detection device 4.

[0075] In this configuration, when the wafer jig 2 is placed on the positioning stage 3, the wafer jig 2 is positioned by the conical surface 23. Then, the robot 1 holds the wafer jig 2 positioned on the positioning stage 3. If the actual position of the hand 10 deviates when holding the wafer jig 2, this deviation is represented as a positional deviation of the wafer jig 2 in the position deviation detection device 4. Therefore, the displacement generated between the commanded position and the actual position of the robot 1 can be easily detected by the position deviation detection device 4. Thus, the displacement required to correct the commanded position for the purpose of improving the motion accuracy of the robot 1 can be automatically obtained via the wafer jig 2 and the position deviation detection device 4. Therefore, significant labor reduction can be achieved.

[0076] In addition, in the robot system 100 of this embodiment, the conical surface 23 is formed around the circle below the wafer jig 2.

[0077] Therefore, since a large-diameter conical surface 23 can be obtained, the positioning accuracy of the center of the wafer fixture 2 can be improved.

[0078] In addition, in the robot system 100 of this embodiment, the wafer jig 2 has a portion with a thickness greater than that of the wafer 20.

[0079] Therefore, the conical surface 23 can be easily configured on the wafer fixture 2.

[0080] In addition, in the robot system 100 of this embodiment, a plurality of contact components 31 are arranged on the positioning stage 3.

[0081] Therefore, by positioning multiple parts, the positioning accuracy of the center of the wafer fixture 2 can be improved.

[0082] Next, variations of the described embodiment will be explained. Figure 8 This is a diagram showing a modified example of the wafer fixture 2x. Furthermore, in the description of this modified example, sometimes the same numbers as those in the described embodiment are assigned to components, and descriptions are omitted.

[0083] In the wafer fixture 2x of this modified example, as Figure 8 As shown, the flange portion 21b of the aforementioned embodiment is omitted, and the configuration is formed only for the portion corresponding to the positioning body 21a. The outer peripheral surface of the wafer jig 2x is parallel to the central axis 2c. In other words, a tapered surface is not formed on the outer periphery of the wafer jig 2x.

[0084] Multiple (three in this embodiment) conical insertion holes 24 are formed on the lower 22x of the wafer jig 2x. The inner peripheral surface of the insertion holes 24 forms a conical surface 23x. The diameter of the conical surface 23x increases as it faces downward.

[0085] The positioning stage 3x corresponding to the wafer fixture 2x has, for example, a base portion 30 formed in the shape of a circular plate and a plurality of (three in this embodiment) contact components 31x.

[0086] The contact member 31x is a rod-shaped member with a hemispherical front end. The contact member 31x is arranged such that it protrudes upward from the base portion 30 with its length direction pointing vertically. Each contact member 31x is positioned corresponding to each insertion hole 24 of the wafer jig 2x.

[0087] In this modified example, the conical surface 23x can also guide the wafer jig 2x by increasing its relative height as it contacts the contact member 31x, thereby bringing the central axis 2c of the wafer jig 2x closer to a predetermined position. As a result, the wafer jig 2x is suitably guided by the conical surface 23x with its center located on the same vertical line as the center 3c of the positioning stage 3x.

[0088] The number of contact parts 31x and insertion holes 24 can be more than four or less. When the number of contact parts 31x is one or two, it is preferable to provide one or more support parts (not shown) on the positioning stage 3 that are in contact with the lower 22x of the wafer jig 2x, so that the wafer jig 2x can be stabilized.

[0089] As explained above, in the robot system 100 with the wafer jig 2x of this modified example, an insertion hole 24 is formed on the underside of the wafer jig 2x, allowing the contact member 31x to be inserted from below. A conical surface 23x is disposed within the insertion hole 24.

[0090] This enables the miniaturization of the contact component 31x.

[0091] The preferred embodiments and variations of this disclosure have been described above, but the configuration can be changed, for example, in the following ways.

[0092] In the described embodiment, the displacement acquisition unit 51 acquires the displacement based on the detection result of the linear sensor 42 of the position offset detection device 4. Alternatively, the offset of the center of the rotatable stage 41 of the wafer jig 2 can be calculated on the position offset detection device 4 side, and the acquired offset can be transmitted from the position offset detection device 4 to the controller 5. In this case, the displacement acquisition unit 51 acquires the displacement based on the offset received by the controller 5 from the position offset detection device 4.

[0093] The control of the position offset detection device 4 (e.g., the control of the electric motor driving the rotary table 41) can be implemented by a controller that is independent of the position offset detection device 4, or it can be implemented by the controller 5 that controls the robot 1. When both the robot 1 and the position offset detection device 4 are controlled by a single controller 5, it is easy to coordinate the control of each of the electric motors driving the rotary table 41 that drives the position offset detection device 4 and the drive motors that drive each part of the robot 1. As a result, the accuracy of displacement acquisition can be improved.

[0094] The positioning stage 3 can also have more than three contact parts 31. The shapes of each contact part 31 can also be different.

[0095] The outer diameter of the flange 21b or the outer diameter of the wafer clamp 2x may be the same as or different from the outer diameter of the wafer 20.

[0096] The conical surface 23 may also be formed on the contact component 31 instead of the wafer fixture 2.

[0097] A flange 21b may also be formed on the wafer fixture 2x in the modified example.

[0098] The functions of the elements disclosed in this specification can be executed using circuits or processing circuits that include general-purpose processors, special-purpose processors, integrated circuits, ASICs (Application-Specific Integrated Circuits), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. Because it includes transistors or other circuitry, a processor can be considered as a processing circuit or circuit. In this disclosure, a circuit, unit, or means is hardware that performs the listed functions, or can also be hardware programmed to perform the listed functions. The hardware can be the hardware disclosed in this specification, or it can be other known hardware programmed or configured to perform the listed functions. In the case of a processor where the hardware is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used in the configuration of the hardware and / or the processor.

Claims

1. A robot system, characterized in that... ,Include: A robot that can hold a wafer using a holding section; A wafer fixture, held by the robot; A positioning stage, which can hold the wafer fixture; A position offset detection device is configured at a position different from the positioning stage and is capable of detecting the position offset of the wafer jig relative to the detection reference position of the position offset detection device. The control unit issues commands to control the robot; as well as The displacement acquisition unit acquires the displacement generated between the commanded position and the actual position of the robot. The positioning stage has a contact component that can contact the wafer jig. A tapered surface is formed on the wafer jig. The conical surface guides the wafer jig in such a way that as the position of the conical surface relative to the contact component increases, the center of the wafer jig approaches a predetermined position, thereby physically and correctly positioning the wafer jig by the positioning stage. According to instructions from the control unit, after placing the wafer jig on the positioning stage, the robot holds the wafer jig and moves it to the position offset detection device in a manner that aligns the center of the holding part with the detection reference position of the position offset detection device. The displacement acquisition unit acquires the displacement based on the position offset detected by the position offset detection device of the transported wafer fixture.

2. The robot system according to claim 1, wherein, The conical surface is formed around the circle below the wafer fixture.

3. The robot system according to claim 1, wherein, An insertion hole is formed on the underside of the wafer jig, allowing the contact member to be inserted from below, and the tapered surface is disposed within the insertion hole.

4. The robot system according to claim 1, wherein, The wafer fixture has a portion that is thicker than the wafer.

5. The robot system according to claim 1, wherein, Multiple contact components are arranged on the positioning platform.

6. A displacement acquisition method for acquiring displacement generated between a commanded position and an actual position of a robot in a robot system, the robot system having: A robot that can hold a wafer using a holding section; A wafer fixture, held by the robot; A positioning stage, which can hold the wafer fixture; A position offset detection device is configured at a position different from the positioning stage and is capable of detecting the position offset of the wafer jig relative to the detection reference position of the position offset detection device. as well as The control unit issues commands to the robot for control, wherein: The positioning stage has a contact component that can contact the wafer jig. A tapered surface is formed on the wafer jig. The conical surface guides the wafer jig in such a way that as the position of the conical surface relative to the contact member increases, the center of the wafer jig approaches a predetermined position, thereby physically and correctly positioning the wafer jig by the positioning stage, and the method is characterized by comprising the following steps: In the first process, the control unit issues instructions to the robot to place the wafer jig on the positioning stage. In the second process, the control unit issues instructions to the robot to move the wafer jig to the position offset detection device in a manner that holds the wafer jig and makes the center of the holding part consistent with the detection reference position of the position offset detection device. as well as In the third step, the displacement is obtained based on the positional offset detected by the position offset detection device of the wafer jig being transported.

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