A mechanical arm zero return control method

Abstract

The application discloses a mechanical arm zero return control method, and relates to the technical field of semiconductors. First, a wafer handling mechanical arm is modeled, and a reference coordinate system xOy of the wafer handling mechanical arm is simulated; then the wafer handling mechanical arm is controlled to normally operate; when two rear arms rotate in the same direction and the rotating angle is theta, alpha-beta-k*360=2theta, and alpha+beta=k*360+A; when the two rear arms rotate in the same direction by theta and then rotate in the opposite direction, alpha+beta=k*360+B<k*360+A, and alpha-beta-k*360=2theta; after power-off and power-on again, alpha and beta are acquired, and whether alpha+beta=k*360+A is established is judged. The mechanical arm zero return control method provided by the application can realize fast zero return of the wafer handling mechanical arm after power-off and power-on again, and the method does not need to open a cavity for operation, saves time and effort, shortens machine recovery time, and improves production efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically, to a method for controlling the return to zero of a robotic arm. Background Technology

[0002] Currently, in the wafer deposition process using semiconductor equipment, robotic arms are needed to handle the wafers for automated transfer. However, when the robotic arm returns to zero after a power outage and subsequent power restoration, it first retracts until the left and right arms collide with the telescopic limit blocks, then rotates to find the rotational zero position, resets the rotational and telescopic zero positions, and finally recalibrates the arm's positioning. This calibration requires opening a cavity, which in wafer deposition equipment necessitates a series of operations such as cooling and vacuum removal, which is time-consuming and labor-intensive, directly leading to extended rework times and reduced production efficiency.

[0003] In view of this, designing a robotic arm zero-return control method that can quickly return to zero and save time and effort is particularly important in semiconductor manufacturing. Summary of the Invention

[0004] The purpose of this invention is to provide a method for controlling the zero return of a robotic arm, which enables the wafer handling robotic arm to quickly return to zero after a power outage and subsequent power restoration, without requiring cavity opening operations, saving time and effort, shortening the rework time, and improving production efficiency.

[0005] The present invention is achieved by the following technical solution.

[0006] A method for controlling the return to zero of a robotic arm is provided, applied to a wafer handling robotic arm. The wafer handling robotic arm includes a support arm and two support arm assemblies. The support arm includes a crossbeam and a forearm connected to each other. The support arm assembly includes a drive member, a rear arm, and a middle arm. The drive member is driven to the rear arm, and the rear arm is hinged to the middle arm. One end of the crossbeam is hinged to one middle arm, and the other end is hinged to the other middle arm. The two drive members are coaxially arranged and rotate synchronously at the same speed. The two drive members are used to drive the two rear arms to rotate in the same direction, so that the forearm rotates. The two drive members are also used to drive the two rear arms to rotate in opposite directions, so that the forearm extends and retracts.

[0007] The robotic arm's zero-return control methods include:

[0008] A model of a wafer handling robot arm is created, and the reference coordinate system xOy of the wafer handling robot arm is simulated. Point O is the projection point of the axis of the driving component. When the wafer handling robot arm is in the zero position, the x-axis is the angle bisector of the two rear arms, α=β, and α+β=A. In the formula, α is the angle between one rear arm and the +x-axis, β is the angle between the other rear arm and the +x-axis, and A is a constant.

[0009] Controlling the wafer handling robotic arm to operate normally; when the two rear arms rotate in the same direction and the rotation angle is θ, α-β-k*360=2θ, and α+β=k*360+A; when the two rear arms rotate in the same direction by θ and then rotate in opposite directions, α+β=k*360+B<k*360+A, and α-β-k*360=2θ, where k=1, -1 or 0, and B is a variable;

[0010] After power is cut off and then restored, α and β are obtained, and it is determined whether α+β=k*360+A is true. If true, θ is calculated by θ=(α-β-k*360) / 2, and then the two rear arms are controlled to rotate in the same direction with a rotation angle of -θ, so that the wafer handling robot arm returns to the zero position. If false, δ is calculated by δ=[A-(α+β)mod360] / 2, and then the two rear arms are controlled to rotate in opposite directions with a rotation angle of -δ. Then the two rear arms are controlled to rotate in the same direction with a rotation angle of -(α-β) / 2, so that the wafer handling robot arm returns to the zero position.

[0011] Optionally, in the steps of controlling the normal operation of the wafer handling robot arm, if the two rear arms are located on opposite sides of the x-axis and A is a positive number, then k = 1; if the two rear arms are located on opposite sides of the x-axis and A is a negative number, then k = -1; if the two rear arms are located on the same side of the x-axis, or if any rear arm coincides with the x-axis, then k = 0.

[0012] Optionally, in the steps of controlling the normal operation of the wafer handling robot arm, if θ is a positive number, the rear arm rotates clockwise; if θ is a negative number, the rear arm rotates counterclockwise.

[0013] Optionally, after simulating the reference coordinate system xOy of the wafer handling robot, the robot's homing control method further includes:

[0014] The moving coordinate system mOn of the simulated wafer handling robot arm can rotate relative to the reference coordinate system xOy as the wafer handling robot arm rotates. The m-axis is always the angle bisector of the two rear arms.

[0015] Optionally, the wafer handling robotic arm also includes a base, a magnetic fluid seal connector, a first turntable, and a second turntable. The two driving components are a first motor and a second motor, which are arranged face-to-face and overlapped, and are both installed in the base. The first motor is connected to the first turntable through the magnetic fluid seal connector, and the second motor is connected to the second turntable through the magnetic fluid seal connector. The first turntable and the second turntable rotate in cooperation. The first turntable is connected to one rear arm, and the second turntable is connected to the other rear arm.

[0016] Optionally, the first motor includes a first motor body and a first output disk, the magnetic fluid sealing connector includes a magnetic fluid outer shaft turntable, the first rotor of the first motor body is connected to the first output disk, the first output disk is connected to the magnetic fluid outer shaft turntable through a first clamp, and the magnetic fluid outer shaft turntable is connected to the first turntable.

[0017] Optionally, the second motor includes a second motor body, a second output disk, and a drive shaft. The magnetic fluid sealing connector also includes a magnetic fluid inner shaft chuck. The second motor body is located below the first motor body. The first motor body has a first clearance hole in its middle, and the second motor body has a second clearance hole in its middle. The second rotor of the second motor body is connected to the second output disk. The second output disk is connected to the drive shaft through a second clamp. The drive shaft passes through the second clearance hole and the first clearance hole in sequence and is connected to the magnetic fluid inner shaft chuck. The magnetic fluid inner shaft chuck is connected to the second turntable.

[0018] Optionally, the wafer handling robotic arm also includes a first angle sensor and a second angle sensor, both of which are mounted in the base. The first angle sensor is used to detect the rotation angle of the first motor, and the second angle sensor is used to detect the rotation angle of the second motor.

[0019] Optionally, there is one forearm, which is connected to the middle of the crossbeam;

[0020] Alternatively, there are two forearms, which are positioned opposite each other at both ends of the crossbeam and together with the crossbeam form a U-shape.

[0021] Optionally, the wafer handling robotic arm also includes a timing belt, one end of which is connected to the hinge axis between the crossbeam and one of the middle arms, and the other end of which is connected to the hinge axis between the crossbeam and another middle arm.

[0022] The robotic arm zero-return control method provided by this invention has the following beneficial effects:

[0023] The robotic arm zero-return control method provided by this invention first models the wafer handling robotic arm and simulates its reference coordinate system xOy, where point O is the projection point of the axis of the driving component. When the wafer handling robotic arm is in the zero position, the x-axis is the angle bisector of the two rear arms, α=β, and α+β=A, where α is the angle between one rear arm and the +x-axis, β is the angle between the other rear arm and the +x-axis, and A is a constant. Then, the wafer handling robotic arm is controlled to operate normally. When the two rear arms rotate in the same direction with a rotation angle of θ, α-β-k*360=2θ, and α+β=k*360+A. When the two rear arms rotate in the same direction by θ and then in opposite directions, α+β=k*360+A. B < k*360 + A, and α - β - k*360 = 2θ, where k = 1, -1, or 0, and B is a variable; after power is cut off and then restored, α and β are obtained, and it is determined whether α + β = k*360 + A is true; if true, θ is calculated by θ = (α - β - k*360) / 2, and then the two rear arms are controlled to rotate in the same direction with a rotation angle of -θ, so that the wafer handling robot arm returns to the zero position; if false, δ is calculated by δ = [A - (α + β) mod 360] / 2, and then the two rear arms are controlled to rotate in opposite directions with a rotation angle of -δ, and then the two rear arms are controlled to rotate in the same direction with a rotation angle of -(α - β) / 2, so that the wafer handling robot arm returns to the zero position. Compared with the prior art, the robotic arm zero-return control method provided by the present invention adopts the step of judging whether α+β=k*360+A is true and controlling the rear arm in different ways depending on whether it is true or not. Therefore, it can realize the rapid zero-return of the wafer handling robotic arm after power failure and power restoration, without the need for cavity opening operation, saving time and effort, shortening the rework time, and improving production efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of the wafer handling robot arm from a first perspective, which is used in the robot arm zero-return control method provided in the first embodiment of the present invention.

[0026] Figure 2 A schematic diagram of the wafer handling robot arm from a second perspective, which is used in the robot arm zero-return control method provided in the first embodiment of the present invention.

[0027] Figure 3A schematic diagram of the wafer handling robot arm from a third perspective, which is used in the robot arm zero-return control method provided in the first embodiment of the present invention.

[0028] Figure 4 A schematic diagram of the structure of the first motor in the wafer handling robotic arm to which the robotic arm zero-return control method provided in the first embodiment of the present invention is applied;

[0029] Figure 5 A schematic diagram of the structure of the second motor in the wafer handling robot arm to which the robot arm zero-return control method provided in the first embodiment of the present invention is applied;

[0030] Figure 6 A schematic diagram of the structure of the magnetohydrodynamic sealing connector in the wafer handling robot arm used in the robot arm zero-return control method provided in the first embodiment of the present invention;

[0031] Figure 7 This is a model diagram of the robotic arm zero-return control method provided in the first embodiment of the present invention when the wafer handling robotic arm is in the zero position;

[0032] Figure 8 A model diagram of the robotic arm zero-return control method provided in the first embodiment of the present invention after the wafer handling robotic arm has rotated a certain angle;

[0033] Figure 9 The model diagram of the robotic arm zero-return control method provided in the first embodiment of the present invention after the wafer handling robotic arm has rotated a certain angle and extended a certain distance;

[0034] Figure 10 A schematic diagram of the structure of a wafer handling robotic arm used in the robotic arm zero-return control method provided in the second embodiment of the present invention.

[0035] Icons: 100 - Wafer handling robotic arm; 110 - Load-bearing arm; 111 - Crossbeam; 112 - Forearm; 120 - Support arm assembly; 121 - Drive unit; 122 - Rear arm; 123 - Middle arm; 124 - First motor; 1241 - First motor body; 1242 - First output plate; 1243 - First stator; 1244 - First rotor; 1245 - First clamp; 1246 - First clearance hole; 125 - Second motor; 1251 - Second motor 1252-Second output disc; 1253-Drive shaft; 1254-Second clearance hole; 1255-Second rotor; 1256-Second stator; 1257-Second clamp; 130-Base; 140-Magnetic fluid sealing connector; 141-Magnetic fluid outer shaft turntable; 142-Magnetic fluid inner shaft chuck; 150-First turntable; 160-Second turntable; 170-First angle sensor; 180-Second angle sensor; 190-Synchronous belt. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] In the description of this invention, it should be noted that the terms "inner," "outer," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0040] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "connected," "installed," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, features in the following embodiments can be combined with each other.

[0042] First Embodiment

[0043] Please refer to the reference. Figures 1 to 6This invention provides a method for controlling the zero-return of a robotic arm, enabling precise zero-return. It allows the wafer handling robotic arm 100 to quickly return to zero after a power outage and subsequent power restoration, eliminating the need for cavity opening operations, saving time and effort, shortening rework time, and improving production efficiency.

[0044] It should be noted that the robotic arm zero-return control method is applied to the wafer handling robotic arm 100, which is used to handle wafers to achieve automated wafer transfer, thereby improving wafer deposition efficiency.

[0045] The wafer handling robotic arm 100 includes a support arm 110 and two support arm assemblies 120. The support arm 110 includes a crossbeam 111 and a forearm 112 connected to each other. The forearm 112 is used to support the wafer, which is placed at the end of the forearm 112 away from the crossbeam 111, i.e., at the free end of the forearm 112. The support arm assembly 120 includes a drive member 121, a rear arm 122, and a middle arm 123. The drive member 121 is drivenly connected to the rear arm 122, and the rear arm 122 is hinged to the middle arm 123. One end of the crossbeam 111 is hinged to one middle arm 123, and the other end is hinged to the other middle arm 123. That is, the two middle arms 123 are hinged together by the crossbeam 111. Both middle arms 123 can rotate relative to the crossbeam 111, and the crossbeam 111 can simultaneously limit the movement of both middle arms 123. Specifically, the two drive members 121 are coaxially arranged and rotate synchronously at the same speed. Each drive member 121 can drive one rear arm 122 to rotate. The two drive members 121 are used to drive the two rear arms 122 to rotate in the same direction, so as to drive the forearm 112 to rotate through the two middle arms 123 and a crossbeam 111. The two drive members 121 are also used to drive the two rear arms 122 to rotate in opposite directions, so as to drive the forearm 112 to extend and retract through the two middle arms 123 and a crossbeam 111.

[0046] In this embodiment, there are two forearms 112, which are positioned opposite each other at both ends of the crossbeam 111 and together with the crossbeam 111 form a U-shape. The crossbeam 111 and the two forearms 112 can rotate or extend synchronously. Specifically, each forearm 112 is used to support one wafer. The two forearms 112 work together to simultaneously realize the picking and feeding functions of two wafers, thereby improving handling efficiency.

[0047] Furthermore, the wafer handling robotic arm 100 also includes a base 130, a magnetic fluid seal connector 140, a first turntable 150, and a second turntable 160. The two drive components 121 are a first motor 124 and a second motor 125, respectively. The first motor 124 and the second motor 125 are arranged face-to-face and overlapped, and both are mounted within the base 130. The base 130 is used to limit and fix the first motor 124 and the second motor 125. Specifically, the first motor 124 is connected to the first turntable 150 via the magnetic fluid seal connector 140, and the second motor 125 is connected to the second turntable 160 via the magnetic fluid seal connector 140. The magnetic fluid seal connector 140 enables stable and reliable transmission while ensuring the sealing of the deposition chamber. In this embodiment, the first turntable 150 and the second turntable 160 rotate in coordination, and the first turntable 150 and the second turntable 160 can limit each other to ensure rotation accuracy; the first turntable 150 is connected to one rear arm 122, and the second turntable 160 is connected to the other rear arm 122, so as to realize the independent rotation function of the two rear arms 122 under the action of the first motor 124 and the second motor 125 respectively.

[0048] The first motor 124 includes a first motor body 1241 and a first output disk 1242. The magnetic fluid sealed connector 140 includes a magnetic fluid outer shaft turntable 141. The first stator 1243 of the first motor body 1241 is fixedly connected to the base 130 to fix the position of the first motor body 1241. The first rotor 1244 of the first motor body 1241 is connected to the first output disk 1242. The first output disk 1242 is connected to the magnetic fluid outer shaft turntable 141 through a first clamp 1245. The magnetic fluid outer shaft turntable 141 is connected to the first turntable 150. Specifically, when the first motor body 1241 is started, the first rotor 1244 drives the first output disk 1242 to rotate, which in turn drives the first turntable 150 to rotate through the magnetic fluid outer shaft turntable 141, thereby driving a rear arm 122 to rotate. The first output disk 1242 is connected to the magnetic fluid outer shaft turntable 141 through the first clamp 1245, which can realize the rigid transmission of the corresponding rear arm 122 and ensure precise control of the rotation angle of the rear arm 122.

[0049] The second motor 125 includes a second motor body 1251, a second output disk 1252, and a drive shaft 1253. The magnetic fluid sealing connector 140 also includes a magnetic fluid inner shaft chuck 142. The second motor body 1251 is located below the first motor body 1241. The first motor body 1241 has a first clearance hole 1246 in its middle, and the second motor body 1251 has a second clearance hole 1254 in its middle. The second stator 1256 of the second motor body 1251 is fixedly connected to the base 130 to fix the position of the second motor body 1251. The second rotor 1255 of the second motor body 1251 is connected to the second output disk 1252. The second output disk 1252 is connected to the drive shaft 1253 through a second clamp 1257. The drive shaft 1253 passes through the second clearance hole 1254 and the first clearance hole 1246 in sequence and is connected to the magnetic fluid inner shaft chuck 142. The magnetic fluid inner shaft chuck 142 is connected to the second turntable 160. Specifically, when the second motor body 1251 is started, the second rotor 1255 drives the second output disk 1252 to rotate, which in turn drives the magnetic fluid inner shaft chuck 142 to rotate via the transmission shaft 1253, thereby driving the second turntable 160 to rotate, and then driving the other rear arm 122 to rotate. The second output disk 1252 is connected to the magnetic fluid inner shaft chuck 142 via the second clamp 1257 and the transmission shaft 1253, which can realize the rigid transmission of the corresponding rear arm 122 and ensure precise control of the rotation angle of the rear arm 122.

[0050] Optionally, the wafer handling robotic arm 100 further includes a first angle sensor 170 and a second angle sensor 180. Both the first angle sensor 170 and the second angle sensor 180 are mounted within the base 130. The first angle sensor 170 detects the rotation angle of the first motor 124, and the second angle sensor 180 detects the rotation angle of the second motor 125, facilitating the robotic arm's zero-return control method. In this embodiment, both the first angle sensor 170 and the second angle sensor 180 are grating ruler sensors.

[0051] Optionally, the wafer handling robotic arm 100 further includes a timing belt 190. One end of the timing belt 190 is connected to the outer cylindrical surface of the hinge shaft between the crossbeam 111 and one of the middle arms 123, and the other end is connected to the outer cylindrical surface of the hinge shaft between the crossbeam 111 and the other middle arm 123, to ensure that the two middle arms 123 move synchronously. In this embodiment, there are two timing belts 190, and the timing belts 190 are steel belts. The two timing belts 190 work together to further improve the synchronicity of the movement of the two middle arms 123.

[0052] It should be noted that since the first motor 124 is stacked above the second motor 125, with the front of the first motor 124 facing upwards and the front of the second motor 125 facing downwards, when the driving directions of the first motor 124 and the second motor 125 are opposite, the rotation directions of the two rear arms 122 are the same, and when the driving directions of the first motor 124 and the second motor 125 are the same, the rotation directions of the two rear arms 122 are opposite. Based on this, when the first motor 124 and the second motor 125 drive in the same direction and counterclockwise, the rotation directions of the two rear arms 122 are opposite, and the entire support arm 110 extends forward; when the first motor 124 and the second motor 125 drive in the same direction and clockwise, the rotation directions of the two rear arms 122 are opposite, and the entire support arm 110 retracts backward; when the first motor 124 drives clockwise and the second motor 125 drives counterclockwise, the rotation directions of the two rear arms 122 are the same, and the entire support arm 110 rotates clockwise; when the first motor 124 drives counterclockwise and the second motor 125 drives clockwise, the rotation directions of the two rear arms 122 are the same, and the entire support arm 110 rotates counterclockwise.

[0053] Please refer to the reference. Figures 7 to 9 The robotic arm's zero-return control method includes the following steps:

[0054] Step S110: Model the wafer handling robot arm 100 and simulate the reference coordinate system xOy of the wafer handling robot arm 100, where point O is the projection point of the axis of the drive component 121. When the wafer handling robot arm 100 is in the zero position, the x-axis is the angle bisector of the two rear arms 122, α=β, and α+β=A, where α is the angle between one rear arm 122 and the +x-axis, β is the angle between the other rear arm 122 and the +x-axis, and A is a constant.

[0055] It should be noted that in step S110, the wafer handling robot arm 100 is modeled using 3D software. The rear arm 122, middle arm 123 and crossbeam 111 of the wafer handling robot arm 100 are all simulated as line segments, and the drive component 121 of the wafer handling robot arm 100 is simulated as a circle. The circles formed by the simulation of two drive components 121 are overlapped. The midpoint of this circle is the axis projection point of the drive component 121. The rear arm 122, middle arm 123 and crossbeam 111 can all rotate around this axis projection point.

[0056] Furthermore, the axis projection point of the drive member 121 is set as point O, and the two rear arms 122 are connected to point O. The two rear arms 122 can rotate under the action of the two drive members 121 (first motor 124 and second motor 125), that is, rotate in the reference coordinate system xOy, so as to drive the crossbeam 111 to rotate or extend through the two middle arms 123 respectively, thereby driving the front arm 112 to rotate or extend, and thus realizing the wafer handling function.

[0057] In this embodiment, when the wafer handling robot arm 100 is in the zero position, the rear arm 122, the middle arm 123, and the crossbeam 111 are all located in the second and third quadrants of the reference coordinate system xOy. At this time, the two rear arms 122 are positioned opposite each other on both sides of the x-axis, and the x-axis is the angle bisector of the two rear arms 122. Specifically, the x-axis includes two segments: the +x-axis and the -x-axis. Point O is located between the +x-axis and the -x-axis. α is the angle between one rear arm 122 and the +x-axis, and β is the angle between the other rear arm 122 and the +x-axis. When the wafer handling robot arm 100 is in the zero position, the -x-axis is the angle bisector of the two rear arms 122.

[0058] Step S120: Simulate the moving coordinate system mOn of the wafer handling robot arm 100. The moving coordinate system mOn can rotate relative to the reference coordinate system xOy as the wafer handling robot arm 100 rotates. The m-axis is always the angle bisector of the two rear arms 122.

[0059] It should be noted that in step S120, to facilitate intuitive observation of the motion state of the wafer handling robot arm 100 within the reference coordinate system xOy, a simulated moving coordinate system mAn of the wafer handling robot arm 100 is formed. The moving coordinate system mAn and the reference coordinate system xOy share the same O point, both being projection points of the axis of the driving component 121. The moving coordinate system mAn rotates as the two rear arms 122 rotate in the same direction, and always maintains the two rear arms 122 positioned opposite each other on both sides of the m-axis, which is always the angle bisector of the two rear arms 122. Specifically, the m-axis includes two segments: the +m-axis and the -m-axis. The O point is located between the +m-axis and the -m-axis, and the -m-axis is always the angle bisector of the two rear arms 122. When the two rear arms 122 rotate in the same direction, the moving coordinate system mAn rotates synchronously relative to the reference coordinate system xOy; when the two rear arms 122 rotate in opposite directions, the moving coordinate system mAn remains stationary relative to the reference coordinate system xOy.

[0060] Furthermore, when the wafer handling robot arm 100 is at the zero position, the moving coordinate system mOn and the reference coordinate system xOy are completely coincident. At this time, the -x axis and the -m axis coincide, and both are the angle bisectors of the two rear arms 122.

[0061] Step S130: Control the wafer handling robotic arm 100 to operate normally; when the two rear arms 122 rotate in the same direction and the rotation angle is θ, α-β-k*360=2θ, and α+β=k*360+A; when the two rear arms 122 rotate in the same direction by θ and then rotate in opposite directions, α+β=k*360+B<k*360+A, and α-β-k*360=2θ, where k=1, -1 or 0, and B is a variable.

[0062] It should be noted that in step S130, if the two rear arms 122 rotate in the same direction, the crossbeam 111 rotates relative to point O, thereby causing the front arm 112 to rotate relative to point O, and thus causing the wafer placed on the front arm 112 to rotate relative to point O; if the two rear arms 122 rotate in opposite directions, the crossbeam 111 moves away from or closer to point O, thereby causing the front arm 112 to move away from or closer to point O, and thus causing the wafer placed on the front arm 112 to move away from or closer to point O.

[0063] Specifically, when the two rear arms 122 rotate in the same direction and the rotation angle is θ, the moving coordinate system mOn rotates by θ along with the rotation of the two rear arms 122 in the same direction, that is, the angle between the +m axis and the +x axis is θ, α-β-k*360=2θ, and α+β=k*360+A. At this time, if the two rear arms 122 are located on both sides of the x-axis and A is a positive number, then k =1; if the two rear arms 122 are located on both sides of the x-axis and A is a negative number, then k =-1; if the two rear arms 122 are located on the same side of the x-axis, or if any rear arm 122 coincides with the x-axis, then k=0.

[0064] Furthermore, when the two rear arms 122 rotate in the same direction by θ and then rotate in the opposite direction, that is, when the two rear arms 122 rotate in the opposite direction with an angle of θ between the +m axis and the +x axis, α+β=k*360+B<k*360+A, and α-β-k*360=2θ, if the two rear arms 122 are located on opposite sides of the x-axis and A is positive, then k =1; if the two rear arms 122 are located on opposite sides of the x-axis and A is negative, then k =-1; if the two rear arms 122 are located on the same side of the x-axis, or if either rear arm 122 coincides with the x-axis, then k =0.

[0065] It should be noted that when the drive component 121 drives the rear arm 122 to rotate and the rotation angle is θ, if θ is a positive number, the rear arm 122 rotates clockwise; if θ is a negative number, the rear arm 122 rotates counterclockwise.

[0066] Step S140: After power is cut off and then restored, obtain α and β, and determine whether α+β=k*360+A is true; if true, first calculate θ using θ=(α-β-k*360) / 2, then control the two rear arms 122 to rotate in the same direction with a rotation angle of -θ, so that the wafer handling robot arm 100 returns to the zero position; if false, first calculate δ using δ=[A-(α+β)mod360] / 2, then control the two rear arms 122 to rotate in opposite directions with a rotation angle of -δ, then control the two rear arms 122 to rotate in the same direction with a rotation angle of -(α-β) / 2, so that the wafer handling robot arm 100 returns to the zero position.

[0067] It should be noted that in step S140, after power is cut off and then restored, the system reads α and β at this time and determines whether α+β=k*360+A is true. If it is true, it means that the wafer handling robot arm 100 only rotated before the power was cut off, and did not extend or retract, or it extended or retracted but eventually retracted completely. At this time, θ is first calculated by θ=(α-β-k*360) / 2, and then the two rear arms 122 are controlled to rotate in the same direction with a rotation angle of -θ, so that the two rear arms 122 return to the initial position, so that the moving coordinate system mOn and the reference coordinate system xOy are restored to the same state, thereby making the wafer handling robot arm 100 return to the zero position. If this is not the case, it means that the wafer handling robot arm 100 not only rotated but also extended before the power was cut off. In this case, first calculate δ using δ=[A-(α+β)mod360] / 2, then control the two rear arms 122 to rotate in opposite directions with a rotation angle of -δ, so that the crossbeam 111 is completely retracted. Then control the two rear arms 122 to rotate in the same direction with a rotation angle of -(α-β) / 2, so that the two rear arms 122 return to their initial positions, so that the moving coordinate system mAn and the reference coordinate system xOy are restored to the same state, thereby making the wafer handling robot arm 100 return to the zero position.

[0068] The robotic arm zero-return control method provided in this embodiment of the invention first simulates the reference coordinate system xOy of the wafer handling robotic arm 100, where point O is the projection point of the axis of the driving component 121. When the wafer handling robotic arm 100 is in the zero position, the x-axis is the angle bisector of the two rear arms 122, α=β, and α+β=A, where α is the angle between one rear arm 122 and the +x-axis, β is the angle between the other rear arm 122 and the +x-axis, and A is a constant. Then, the wafer handling robotic arm 100 is controlled to operate normally. When the two rear arms 122 rotate in the same direction with a rotation angle of θ, α-β-k*360=2θ, and α+β=k*360+A. When the two rear arms 122 rotate in the same direction by θ and then in opposite directions, α+β=k*360. +B<k*360+A, and α-β-k*360=2θ, where k=1, -1 or 0, and B is a variable; after power is cut off and power is restored, α and β are obtained, and it is determined whether α+β=k*360+A is true; if true, θ is calculated by θ=(α-β-k*360) / 2, and then the two rear arms 122 are controlled to rotate in the same direction with a rotation angle of -θ, so that the wafer handling robot arm 100 returns to the zero position; if false, δ is calculated by δ=[A-(α+β)mod360] / 2, and then the two rear arms 122 are controlled to rotate in opposite directions with a rotation angle of -δ, and then the two rear arms 122 are controlled to rotate in the same direction with a rotation angle of -(α-β) / 2, so that the wafer handling robot arm 100 returns to the zero position. Compared with the prior art, the robotic arm zero-return control method provided by the present invention adopts the step of judging whether α+β=k*360+A is true and controlling the rear arm 122 in different ways when it is true or not. Therefore, it can realize the rapid zero-return of the wafer handling robotic arm 100 after power failure and power restoration, without the need for cavity opening operation, saving time and effort, shortening the rework time, and improving production efficiency.

[0069] Second Embodiment

[0070] Please refer to Figure 10 This invention provides a wafer handling robotic arm 100. Compared with the first embodiment, the difference in this embodiment is that the length of the crossbeam 111 is shorter and the number of forearms 112 is different.

[0071] In this embodiment, there is one forearm 112. The forearm 112 is connected to the middle of the crossbeam 111. The end of the forearm 112 away from the crossbeam 111 is used to carry the wafer. That is, the wafer is placed at the free end of the forearm 112. The forearm 112 is used to carry the wafer to realize the wafer picking and feeding functions.

[0072] The beneficial effects of the robotic arm zero-return control method provided in this embodiment of the invention are the same as those in the first embodiment, and will not be repeated here.

[0073] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling the homing of a robotic arm, characterized in that, This invention relates to a wafer handling robotic arm, comprising a support arm and two support arm assemblies. The support arm includes a crossbeam and a forearm connected to each other. Each support arm assembly includes a drive member, a rear arm, and a middle arm. The drive member is kinetically connected to the rear arm, and the rear arm is hinged to the middle arm. One end of the crossbeam is hinged to one of the middle arms, and the other end is hinged to the other middle arm. The two drive members are coaxially arranged and rotate synchronously at the same speed. The two drive members are used to drive the two rear arms to rotate in the same direction, thereby rotating the forearm. The two drive members are also used to drive the two rear arms to rotate in opposite directions, thereby extending and retracting the forearm. The robotic arm zero-return control method includes: The wafer handling robot arm is modeled, and the reference coordinate system xOy of the wafer handling robot arm is simulated, where point O is the projection point of the axis of the driving component. When the wafer handling robot arm is in the zero position, the x-axis is the angle bisector of the two rear arms, α=β, and α+β=A, where α is the angle between one rear arm and the +x-axis, β is the angle between the other rear arm and the +x-axis, and A is a constant. Control the wafer handling robotic arm to operate normally; when the two rear arms rotate in the same direction and the rotation angle is θ, α-β-k*360=2θ, and α+β=k*360+A; when the two rear arms rotate in the same direction by θ and then rotate in opposite directions, α+β=k*360+B<k*360+A, and α-β-k*360=2θ, where k=1, -1 or 0, and B is a variable; After power is cut off and then restored, α and β are obtained, and it is determined whether α+β=k*360+A is true. If true, θ is calculated by θ=(α-β-k*360) / 2, and then the two rear arms are controlled to rotate in the same direction with a rotation angle of -θ, so that the wafer handling robot arm returns to the zero position. If false, δ is calculated by δ=[A-(α+β)mod360] / 2, and then the two rear arms are controlled to rotate in opposite directions with a rotation angle of -δ. Then the two rear arms are controlled to rotate in the same direction with a rotation angle of -(α-β) / 2, so that the wafer handling robot arm returns to the zero position.

2. The robotic arm homing control method according to claim 1, characterized in that, In the step of controlling the normal operation of the wafer handling robot arm, if the two rear arms are located on opposite sides of the x-axis and A is a positive number, then k = 1; if the two rear arms are located on opposite sides of the x-axis and A is a negative number, then k = -1; if the two rear arms are located on the same side of the x-axis, or if any of the rear arms coincides with the x-axis, then k = 0.

3. The robotic arm zero-return control method according to claim 1, characterized in that, In the step of controlling the normal operation of the wafer handling robot arm, if θ is a positive number, the rear arm rotates clockwise; if θ is a negative number, the rear arm rotates counterclockwise.

4. The robotic arm zero-return control method according to claim 1, characterized in that, After the step of simulating the reference coordinate system xOy of the wafer handling robot arm, the robot arm zero-return control method further includes: The moving coordinate system mOn of the simulated wafer handling robot arm can rotate relative to the reference coordinate system xOy as the wafer handling robot arm rotates, and the m-axis is always the angle bisector of the two rear arms.

5. The robotic arm homing control method according to claim 1, characterized in that, The wafer handling robotic arm also includes a base, a magnetohydrodynamic (MHD) sealed connector, a first turntable, and a second turntable. The two driving components are a first motor and a second motor, which are arranged face-to-face and overlapped, and are both installed in the base. The first motor is connected to the first turntable through the MHD sealed connector, and the second motor is connected to the second turntable through the MHD sealed connector. The first turntable and the second turntable rotate in cooperation. The first turntable is connected to one of the rear arms, and the second turntable is connected to the other rear arm.

6. The robotic arm homing control method according to claim 5, characterized in that, The first motor includes a first motor body and a first output disk. The magnetic fluid sealing connector includes a magnetic fluid outer shaft turntable. The first rotor of the first motor body is connected to the first output disk. The first output disk is connected to the magnetic fluid outer shaft turntable through a first clamp. The magnetic fluid outer shaft turntable is connected to the first turntable.

7. The robotic arm homing control method according to claim 6, characterized in that, The second motor includes a second motor body, a second output disk, and a drive shaft. The magnetic fluid sealing connector also includes a magnetic fluid inner shaft chuck. The second motor body is located below the first motor body. The first motor body has a first clearance hole in its middle, and the second motor body has a second clearance hole in its middle. The second rotor of the second motor body is connected to the second output disk. The second output disk is connected to the drive shaft via a second clamp. The drive shaft passes through the second clearance hole and the first clearance hole in sequence and is connected to the magnetic fluid inner shaft chuck. The magnetic fluid inner shaft chuck is connected to the second turntable.

8. The robotic arm homing control method according to claim 5, characterized in that, The wafer handling robotic arm also includes a first angle sensor and a second angle sensor, both of which are installed in the base. The first angle sensor is used to detect the rotation angle of the first motor, and the second angle sensor is used to detect the rotation angle of the second motor.

9. The robotic arm homing control method according to claim 1, characterized in that, The number of forearms is one, and the forearm is connected to the middle of the crossbeam; Alternatively, there may be two forearms, which are positioned opposite each other at both ends of the crossbeam and together with the crossbeam form a U-shape.

10. The robotic arm homing control method according to claim 1, characterized in that, The wafer handling robotic arm also includes a timing belt, one end of which is connected to the hinge axis between the crossbeam and one of the middle arms, and the other end of which is connected to the hinge axis between the crossbeam and another of the middle arms.

Images