Scara robot and method for levelling thereof

Abstract

The present application relates to a kind of SCARA manipulator and its leveling method, belong to mechanical arm technical field, including manipulator body, large arm, middle arm, small arm and wrist, the length ratio of the stem of large arm, middle arm, small arm is 1:2:1;When retracting, small arm rotation center and wrist are reversely offset, so that minimum rotation radius envelope circle and wafer are circumscribed.Mechanical hand is installed on the external shaft formed by X-axis linear motor and Z-axis linear module, and is provided with multi-stage adjusting top wire.The leveling method includes X-axis motor horizontal and Z-direction adjustment, the perpendicularity adjustment of the rotation axis of manipulator body and the droop compensation of each joint angle.The present application considers large stroke and small rotation radius, and is suitable for high-speed high-precision wafer transport in narrow space.

Description

Technical Field

[0001] This invention belongs to the field of robotic arm technology, and in particular relates to a SCARA robotic arm and its leveling method. Background Technology

[0002] SCARA robots (horizontal joint robots) are widely used in semiconductor manufacturing, electronic product assembly, and precision handling due to their high speed, high precision, and excellent planar positioning capabilities. Especially in the front-end module (EFEM) of semiconductor equipment, SCARA robots are responsible for the high-speed transfer of wafers from the wafer cassette to the process cavity.

[0003] Traditional SCARA-type three-segment robotic arms typically employ a symmetrical design with three segments of equal length. For example, in a currently disclosed suspended horizontal multi-joint robot, the first and second arms are roughly the same length. In existing substrate handling devices, the upper arm and forearm also usually have equal lengths. However, when the three segments are of equal length, the minimum turning radius of the robotic arm in the retracted state is large, requiring a large installation space and occupying too much area within the limited space of semiconductor equipment, which is detrimental to the miniaturization and high-density integration of equipment within the EFEM (Electronic Equipment Interior). Conversely, for robotic arm structures with only a large and middle arm, although the turning radius can be smaller, the lack of forearm extension results in a short extension stroke, failing to meet the large stroke, large span, and high-span wafer handling requirements of modern semiconductor processes' vacuum process chambers (VTM). In other words, existing technologies inherently contradict each other between a small turning radius in retraction and a large handling stroke in extension, making it difficult to simultaneously achieve both within the confined space of an EFEM.

[0004] To address the aforementioned shortcomings, existing technologies have proposed improvements such as unequal arm and forearm lengths to improve the reach ratio of the robotic arm. However, these solutions do not optimize the arm-to-forearm length ratio for semiconductor EFEM applications, nor do they adequately consider how to achieve the minimum turning radius through optimal arrangement of the three-section arm in the retracted state. Therefore, their large-stroke handling capacity within limited space still needs improvement. Furthermore, these solutions lack a systematic leveling method to address the sag caused by gravity, making it difficult to meet the stringent requirements of semiconductor processes for end effector horizontal accuracy and vibration control. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a SCARA robotic arm and its leveling method, which can have a minimum turning radius in the retracted state to adapt to installation in confined spaces, while achieving a sufficiently large handling stroke in the extended state to match the requirements of large-span process cavities, and can meet the high precision and high stability requirements of the semiconductor field.

[0006] A SCARA robotic arm, suitable for wafer handling within a limited space in the front-end module of semiconductor equipment, includes:

[0007] The robotic arm body has a drive unit installed inside it;

[0008] The upper arm, with its proximal end mounted on the robotic arm body, is driven by a drive unit to perform horizontal rotation around a vertical axis;

[0009] The middle arm, the proximal end of which is rotatably connected to the distal end of the upper arm;

[0010] The forearm, the proximal end of which is rotatably connected to the distal end of the middle arm;

[0011] The wrist has one end rotatably connected to the distal end of the forearm, and the other end is provided with a wafer transport position.

[0012] The ratio of the length of the upper arm, middle arm, and forearm is 1:2:1.

[0013] Each joint of the upper arm, middle arm, and forearm is equipped with a synchronous belt drive mechanism. The rotation of the upper arm drives the middle arm to move in a predetermined transmission ratio through the synchronous belt located at the elbow joint. The rotation of the middle arm then drives the forearm and the wrist in a coordinated manner through the synchronous belt located at the wrist joint. This ensures that the wrist and wafer transport position maintain a constant posture throughout the entire movement under the input of a single drive unit.

[0014] When the robotic arm is in the retracted position, the rotation center of the forearm is offset to one side relative to the centerline of the minimum rotation radius, while the wrist is offset in the opposite direction. These two offsets are set to allow space to be made at the connection points of the middle arm and forearm, and the connection points of the middle arm and upper arm, and the outer geometric contour of the wafer on the wafer handling position is externally tangent to the envelope circle of the minimum rotation radius; the centerline of the minimum rotation radius is offset relative to the rotation center, so that the wall thickness at the connection point of the forearm and middle arm is equal to the wall thickness at the connection point of the upper arm and middle arm, so as to eliminate the extra space occupied due to the unequal wall thickness at the connection point.

[0015] It also includes an external axis module, which includes an X-axis linear motor and a Z-axis linear module. The Z-axis linear module is mounted on the flange of the X-axis linear motor, and the robot body is mounted on the motion output end of the Z-axis linear module.

[0016] The fixed end of the X-axis linear motor is provided with multiple mounting plates. Each mounting plate is provided with a first adjusting screw, an adjusting structure, and a Z-axis adjusting hole. The first adjusting screw is used to rotate and level the X-axis linear motor in two orthogonal directions. The adjusting structure, in conjunction with the operating tool inserted into the Z-axis adjusting hole, is used to compensate for Z-axis position deviation.

[0017] Multiple second adjustment screws are provided at the connection between the robot body and the Z-axis linear module to adjust the horizontal posture of the robot body and ensure the verticality of the robot body's rotation axis.

[0018] A third adjusting screw is provided at the connection point between the upper arm and the middle arm, a fourth adjusting screw is provided at the connection point between the middle arm and the forearm, and a fifth adjusting screw is provided at the connection point between the forearm and the wrist, which are used to compensate for the angular sag of each corresponding joint due to its own weight.

[0019] The leveling method for a SCARA robotic arm described above includes the following steps:

[0020] The horizontal attitude and vertical position of the X-axis linear motor are adjusted to ensure that the X-axis linear motor remains precisely horizontal within its stroke range;

[0021] Adjust the horizontal orientation of the robot body to keep the rotation axis of the robot body perpendicular at all angles in the circumference.

[0022] The angles between the upper arm and middle arm, the middle arm and forearm, and the forearm and wrist are compensated and adjusted to eliminate the angular sag caused by its own weight, so that the wafer transport position remains horizontal in any posture.

[0023] When adjusting the horizontal attitude and vertical position of the X-axis linear motor, calibration is performed using two degrees of freedom: rotational leveling and Z-axis position compensation.

[0024] When adjusting the horizontal posture of the robot body, the levelness of the wafer handling position at different workstation rotation radii is detected during the rotation of the robot body's rotation axis until the levelness at each workstation rotation radius meets the requirements.

[0025] By employing the above technical solution, the present invention has at least the following beneficial effects:

[0026] This invention sets the ratio of the arm length of the upper arm, middle arm, and forearm to 1:2:1, and coordinates the offset of the forearm rotation center in the opposite direction to the wrist during retraction. This ensures that the connection points between the middle arm and forearm, and between the middle arm and upper arm, have sufficient clearance, while ensuring that the outer contour of the wafer is externally tangent to the envelope circle of the minimum rotation radius. Thus, the minimum rotation radius is obtained under the same extension stroke.

[0027] Compared to traditional three-section arms of equal length, this invention significantly reduces the space occupied in the retracted state while maintaining the same total extension length; at the same time, it achieves a larger transport stroke compared to two-section arms, thus simultaneously meeting the dual requirements of semiconductor EFEM equipment for transporting materials in confined installation spaces and large-span process cavities.

[0028] In addition, the present invention also includes an external axis module that combines an X-axis linear motor and a Z-axis linear module, which can achieve flexible movement with large stroke, large span and high span within a limited space.

[0029] Based on this, the present invention also provides a systematic multi-level leveling method. By adjusting the horizontal and Z-axis positions of the X-axis linear motor, adjusting the verticality of the robot body's rotation axis, and compensating for the angulation of the three-level joints of the upper arm and middle arm, the middle arm and forearm, and the forearm and wrist, the method ultimately ensures that the wafer transport position maintains a precise level under any workstation posture, with minimal operating vibration, thus meeting the semiconductor industry's requirements for high-speed and high-precision wafer transfer. Attached Figure Description

[0030] Figure 1 A schematic diagram (extended position) of the three-section robotic arm in the SCARA robotic arm provided by the present invention;

[0031] Figure 2 A schematic diagram (retracted position) of the three-section robotic arm in the SCARA robotic arm provided by the present invention.

[0032] Figure 3 A schematic diagram of the structural principle of the three-section robotic arm configuration 1 of the SCARA robotic arm provided by the present invention (retracted position);

[0033] Figure 4 A schematic diagram of the structural principle of the three-section robotic arm configuration 1 of the SCARA robotic arm provided by the present invention (extended position);

[0034] Figure 5 A schematic diagram of the structural principle of the three-section robotic arm configuration two provided by the present invention (retracted position);

[0035] Figure 6 A schematic diagram of the structural principle of the three-section robotic arm configuration two (extended position) of the SCARA robotic arm provided by the present invention;

[0036] Figure 7 A schematic diagram of the external shaft module in the SCARA manipulator provided by the present invention;

[0037] Figure 8 This is a schematic diagram of the installation of the external shaft module in the SCARA robot provided by the present invention;

[0038] Figure 9 This is a schematic diagram illustrating the adjustment of the robotic arm body in this invention;

[0039] Figure 10 This is a schematic diagram illustrating the adjustment of the three-section robotic arm in this invention;

[0040] Figure 11 A schematic diagram illustrating the structural principle of concentric structures in existing technologies;

[0041] In the picture:

[0042] 1. Robotic arm body; 2. Upper arm; 3. Middle arm; 4. Forearm; 5. Wrist; 6. Wafer handling position; 7. Rotation center; 8. Minimum rotation radius; 9. Retracted position; 10. Extended position; 11. Z-axis linear module; 12. X-axis linear motor; 13. First adjusting screw; 14. Adjustment structure; 15. Mounting plate; 16. Z-axis adjustment hole; 17. Station rotation radius; 18. Robotic arm body rotation axis; 19. Second adjusting screw; 20. Third adjusting screw; 21. Fourth adjusting screw; 22. Fifth adjusting screw; 23. Arm connection wall thickness; 24. Minimum rotation radius of concentric structure; 25. Wafer outer diameter; 26. Rotation center of concentric structure. Detailed Implementation

[0043] To better explain and facilitate understanding of the present invention, the technical solution and effects of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] like Figures 1-10 As shown, a SCARA robot is suitable for use in semiconductor equipment front-end modules (EFEMs), enabling high-speed, high-precision wafer handling with large strokes, large spans, and high distances within a limited space. Specifically, the SCARA robot includes a robot body 1, a large arm 2, a middle arm 3, a forearm 4, and a wrist 5, with a wafer handling position 6 disposed on the wrist 5. The robot body 1 serves as the mounting base and contains a drive unit. The proximal end of the large arm 2 is mounted on the robot body 1. Specifically, the robot body 1 contains a drive unit, the output of which is connected to a vertically arranged robot body rotation shaft 18. The robot body rotation shaft 18 extends from the upper surface of the robot body 1, and its centerline forms the vertical axis of the proximal end of the large arm 2. The proximal end of the large arm 2 is fixedly mounted on the robot body rotation shaft 18, allowing the drive unit to drive the large arm 2 to rotate horizontally around this vertical axis via the robot body rotation shaft 18. Furthermore, the distal end of the upper arm 2 is rotatably connected to the proximal end of the middle arm 3 via the elbow joint, the distal end of the middle arm 3 is rotatably connected to the proximal end of the forearm 4 via the wrist joint, and the distal end of the forearm 4 is rotatably connected to the wrist 5.

[0045] Preferably, a synchronous belt drive mechanism is provided at each joint: the rotation of the upper arm 2 drives the middle arm 3 to move in a predetermined transmission ratio via a synchronous belt located at the elbow joint; the rotation of the middle arm 3 then drives the forearm 4 and wrist 5 in a coordinated manner via a synchronous belt located at the wrist joint. Through the aforementioned synchronous belt drive combined with the rotational connection structure of each joint, the entire robotic arm can extend, retract, and rotate according to a predetermined motion relationship under a single drive motor. Simultaneously, the wrist 5 and the wafer transport position 6 maintain a constant posture throughout the entire movement, ensuring the directional stability of the wafer transport.

[0046] To achieve both large-stroke transport and minimal space occupation during retraction, the link length ratio of the upper arm 2, middle arm 3, and forearm 4 in this embodiment is 1:2:1. That is, if the joint center distance of the upper arm 2 is L, then the length of the middle arm 3 is 2L, and the length of the forearm 4 is L. This link length ratio is the optimal solution calculated based on planar motion geometry. This ratio ensures that, under the same extension stroke conditions, the robot arm in the retracted state achieves the smallest turning radius. Compared to traditional three-section equal-length arms or only two-section arms, the 1:2:1 link length ratio of the upper arm 2, middle arm 3, and forearm 4 simultaneously addresses the seemingly contradictory requirements of large stroke and small turning radius.

[0047] Specifically, in a preferred embodiment, the lengths of the upper arm 2, middle arm 3, and forearm 4 are 180mm, 360mm, and 180mm, respectively. In the retracted position 9, to further compress the minimum radius of rotation 8 centered on the rotation center 7 of the upper arm 2, the invention shifts the rotation center of the forearm 4 (i.e., the connection point between the forearm 4 and the middle arm 3) 30mm to the right relative to the centerline of the minimum radius of rotation 8, while simultaneously shifting the wrist 5 30mm to the left. This shift design ensures that when the upper arm 2, middle arm 3, and forearm 4 are folded sequentially, there is sufficient space for the connection points between the middle arm 3 and forearm 4, as well as between the middle arm 3 and upper arm 2, avoiding joint interference. Simultaneously, the leftward shift of the wrist 5 compensates for the position of the wafer transport position 6, ensuring that the outer geometric contour of the wafer is precisely tangent to the envelope circle of the minimum radius of rotation 8. In this configuration, the minimum radius of rotation 8 is only 520mm. When extended to position 10, the maximum extended length is designed to be less than the total length of the upper arm 2, middle arm 3 and forearm 4 after they are fully extended, with a margin, thereby ensuring structural rigidity and operational stability under maximum stroke.

[0048] Under the constraint of the synchronous belt drive mechanism, to ensure that the wrist 5 achieves a single degree of freedom linear motion, the upper arm 2 and the forearm 4 always remain parallel. If the centerline of the minimum radius of rotation 8 is concentric with the center of rotation of the arm (i.e., there is no offset), in this retracted posture, the wall thickness at the connection between the forearm 4 and the middle arm 3 and the wall thickness at the connection between the upper arm 2 and the middle arm 3 are not equal, resulting in a larger concentric minimum radius of rotation. However, in this invention, the centerline of the minimum radius of rotation 8 is offset relative to the center of rotation of the arm by a certain distance, shifting it 30mm to the right in the above configuration one to form an eccentric structure; at the same time, the wrist 5 is shifted 30mm in the opposite direction, making the wall thickness 23 at the two arm connections equal, such as... Figure 3 As shown, the minimum radius of gyration 8 at this point is the same as the minimum radius of gyration under the same structure. In other words, through the above offset design, the extra space occupied by the uneven wall thickness at the joint connection is eliminated, further compressing the shrinkage envelope, making the minimum radius of gyration 8 of the offset structure smaller than the minimum radius of gyration 24 of the concentric structure. The center of gyration 26 of the concentric structure, the minimum radius of gyration 24 of the concentric structure, and the outer diameter of the wafer 25 are as follows... Figure 11 As shown.

[0049] As another possible arrangement, such as Figures 5-6 In the second configuration shown, the lengths of the upper arm 2, middle arm 3, and forearm 4 are 180mm, 360mm, and 180mm, respectively. In the retracted position 9, the rotation direction of the upper arm 2 is opposite to that in configuration one, and the rotation angles of the middle arm 3 and forearm 4 are also adjusted accordingly. Similarly, by offsetting the wrist to create joint space and tangent the envelope, the minimum turning radius is 578mm. This second configuration is suitable for situations where the installation orientation of the robot body is limited, requiring the upper arm to fold to the other side. Therefore, by using a 1:2:1 ratio and combining the aforementioned offset compensation, this invention achieves a total extension length of 720mm while controlling the retraction radius to 520mm or 578mm, significantly superior to traditional equal-length three-section arms, realizing a large-span handling capability within a confined EFEM space.

[0050] To adapt to changes in height and horizontal position at different workstations and expand the handling range, the three-section robotic arm, consisting of the upper arm 2, middle arm 3, and lower arm 4, is mounted on an external axis module. The external axis module includes an X-axis linear motor 12 and a Z-axis linear module 11, with the Z-axis linear module 11 mounted side-mounted on the flange of the X-axis linear motor 12. The robotic arm body 1 is mounted on the motion output end of the Z-axis linear module 11. The X-axis linear motor 12 is wall-mounted, providing horizontal linear motion; the Z-axis linear module 11 provides vertical lifting motion. When the process chamber is located at a considerable distance or at different heights, the X-axis linear motor 12 and the Z-axis linear module 11 can be used for coarse positioning first, followed by precise extension, retraction, and rotation of the three-section robotic arm, thereby achieving flexible sheet transfer with large stroke, large span, and high span within a limited space.

[0051] To achieve precise installation and leveling of the entire robotic arm, the SCARA robotic arm is equipped with a multi-stage adjustment mechanism. Specifically, the fixed end of the X-axis linear motor 12 is provided with three mounting plates 15 for wall-mounting the X-axis linear motor 12 onto the equipment support structure. Each mounting plate 15 is provided with a first adjusting screw 13, an adjustment structure 14, and a Z-axis adjustment hole 16. The first adjusting screw 13 is used to rotate and level the X-axis linear motor 12 in two orthogonal directions; the adjustment structure 14 uses a screw-lifting method, in conjunction with an operating tool inserted into the Z-axis adjustment hole 16, to compensate for the positional deviation of the guide rail in the Z-axis. Multiple second adjusting screws 19 are provided at the connection between the robotic arm body 1 and the Z-axis linear module 11 to adjust the horizontal posture of the robotic arm body 1 and ensure the verticality of the robotic arm body rotation axis 18. In addition, a third adjusting screw 20 is provided at the connection point between the upper arm 2 and the middle arm 3, a fourth adjusting screw 21 is provided at the connection point between the middle arm 3 and the forearm 4, and a fifth adjusting screw 22 is provided at the connection point between the forearm 4 and the wrist 5. These three adjusting screws are used to compensate for the angular sag of each corresponding joint due to its own weight, ensuring that the end wafer transport position 6 remains horizontal in any posture.

[0052] Based on the aforementioned SCARA robot, a leveling method is provided to ensure the horizontal accuracy and low vibration characteristics of wafer transport station 6 at any workstation:

[0053] When installing the X-axis linear motor 12, it is fixed to the fixed end of the equipment by three mounting plates 15, and the motor guide rail of the X-axis linear motor 12, i.e. the fixed end of the X-axis linear motor 12, is rotated and leveled in two orthogonal directions by multiple first adjusting screws 13. At the same time, the Z-axis position deviation is compensated by adjusting structure 14, thereby ensuring that the X-axis linear motor 12 maintains a precise level throughout its entire stroke range.

[0054] After X-axis leveling, the robot arm body 1 is mounted on the Z-axis linear module 11, and the horizontal orientation of the robot arm body 1 is finely adjusted using multiple second adjustment screws 19. During the adjustment process, the three-section robot arm rotates one revolution around the robot arm body's rotation axis 18, and the levelness of the wafer transport position 6 is monitored at multiple different workstation rotation radii 17, i.e., wafer transport positions 6 at different horizontal distances. If a horizontal deviation occurs at a certain workstation rotation radius 17, the corresponding second adjustment screw 19 is adjusted until the robot arm body's rotation axis 18 remains absolutely vertical within a 360° range and at each workstation rotation radius 17.

[0055] Although the robotic arm's rotation axis 18 is vertical, the three-section robotic arm will still sag under its own weight when extended, affecting the horizontality of the end effector. Therefore, a third adjusting screw 20 is provided at the connection point between the upper arm 2 and the middle arm 3, a fourth adjusting screw 21 is provided at the connection point between the middle arm 3 and the forearm 4, and a fifth adjusting screw 22 is provided at the connection point between the forearm 4 and the wrist 5. By rotating the third adjusting screw 20, the fourth adjusting screw 21, and the fifth adjusting screw 22 respectively, the angles between the upper arm 2 and the middle arm 3, the middle arm 3 and the forearm 4, and the forearm 4 and the wrist 5 are adjusted sequentially, compensating for the angular deviation caused by gravity step by step.

[0056] Ultimately, after leveling the X-axis linear motor, adjusting the verticality of the robot's rotation axis, and compensating for the three-level joint angles, the wafer transport station 6 can maintain a precise level in any workstation posture, and the vibration during operation is minimal, fully meeting the stringent requirements of semiconductor EFEM for high-speed and high-precision wafer transfer.

Claims

1. A SCARA robotic arm, suitable for wafer handling within a limited space in the front-end module of semiconductor equipment, characterized in that, include: The robotic arm body (1) has a drive unit inside; The upper arm (2) is mounted on the robotic arm body (1) and driven by the drive unit to perform horizontal rotation around the vertical axis. The proximal end of the middle arm (3) is rotatably connected to the distal end of the upper arm (2); Forearm (4), the proximal end of the forearm (4) is rotatably connected to the distal end of the middle arm (3); Wrist (5), one end of wrist (5) is rotatably connected to the distal end of the forearm (4), and the other end is provided with a wafer transport position (6). The length ratio of the upper arm (2), the middle arm (3), and the lower arm (4) is 1:2:1; When the robotic arm is in the retracted position (9), the rotation center of the forearm (4) is offset to one side relative to the center line of the minimum rotation radius (8), and the wrist (5) is offset in the opposite direction. These two offsets are set to allow space to be made up at the connection point between the middle arm (3) and the forearm (4) and the connection point between the middle arm (3) and the upper arm (2), and the outer contour of the wafer geometry on the wafer handling position (6) is externally tangent to the envelope circle of the minimum rotation radius (8); the center line of the minimum rotation radius (8) is offset relative to the rotation center (7), so that the wall thickness at the connection point between the forearm (4) and the middle arm (3) is equal to the wall thickness at the connection point between the upper arm (2) and the middle arm (3), so as to eliminate the extra space occupied due to the unequal wall thickness at the connection point; It also includes an external axis module, which includes an X-axis linear motor (12) and a Z-axis linear module (11). The Z-axis linear module (11) is mounted on the flange of the X-axis linear motor (12), and the robot body (1) is mounted on the motion output end of the Z-axis linear module (11). The fixed end of the X-axis linear motor (12) is provided with multiple mounting plates (15). Each mounting plate (15) is provided with a first adjusting screw (13), an adjusting structure (14), and a z-axis adjusting hole (16). The first adjusting screw (13) is used to rotate and level the X-axis linear motor (12) in two orthogonal directions. The adjusting structure (14) is used in conjunction with the operating tool inserted into the z-axis adjusting hole (16) to compensate for the Z-axis position deviation. Multiple second adjustment screws (19) are provided at the connection between the robot body (1) and the Z-axis linear module (11) to adjust the horizontal posture of the robot body (1) and ensure the verticality of the robot body rotation axis (18). A third adjusting screw (20) is provided at the connection point between the upper arm (2) and the middle arm (3), a fourth adjusting screw (21) is provided at the connection point between the middle arm (3) and the forearm (4), and a fifth adjusting screw (22) is provided at the connection point between the forearm (4) and the wrist (5), which are respectively used to compensate for the angle drop of each corresponding joint due to its own weight.

2. A SCARA robotic arm according to claim 1, characterized in that: Synchronous belt drive mechanisms are provided at each joint of the upper arm (2), middle arm (3) and forearm (4). The rotation of the upper arm (2) drives the middle arm (3) to move in a predetermined transmission ratio through the synchronous belt at the elbow joint. The rotation of the middle arm (3) then drives the forearm (4) and the wrist (5) in a coordinated manner through the synchronous belt at the wrist joint, so that the wrist (5) and the wafer transport position (6) maintain a constant posture throughout the entire movement under the input of a single drive unit.

3. A leveling method for a SCARA robotic arm according to claim 1, characterized in that, Includes the following steps: The horizontal attitude and vertical position of the X-axis linear motor (12) are adjusted to ensure that the X-axis linear motor (12) remains precisely horizontal within its stroke range; Adjust the horizontal posture of the robot body (1) so that the rotation axis (18) of the robot body remains vertical at all angles in the circumferential direction; The angles between the upper arm (2) and the middle arm (3), between the middle arm (3) and the forearm (4), and between the forearm (4) and the wrist (5) are compensated and adjusted respectively to eliminate the angular sag caused by its own weight, so that the wafer transport position (6) remains horizontal in any posture. When adjusting the horizontal attitude and vertical position of the X-axis linear motor (12), calibration is performed using two degrees of freedom: rotational leveling and Z-axis position compensation. When adjusting the horizontal posture of the robot body (1), during the rotation of the robot body's rotating axis (18), the levelness of the wafer handling position (6) at different work station rotation radii (17) is detected until the levelness at each work station rotation radius (17) meets the requirements.

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