Partition track control method for direct-driven manipulator aiming at interference station

Abstract

The invention relates to a partition track control method for a direct-driven manipulator aiming at an interference station, which comprises the following steps of: constructing an obstacle avoidance area and a safety point, so that the front end of a finger and the elbow end of an arm are prevented from being in contact with an interference area of a fan-shaped disc when the manipulator is lifted and rotated; and based on the obstacle avoidance area and the safety point, performing partition track planning control: controlling the manipulator to rotate to the safety point of a certain working area, then lifting the manipulator to a working height, and finally controlling the manipulator to rotate and then execute a telescopic action so as to avoid entering the obstacle avoidance area.

Description

Technical Field

[0001] This invention relates to the fields of intelligent manufacturing, automation control, and semiconductor transmission, specifically a method for zoned trajectory control of a direct-drive robot for interference workstations. Background Technology

[0002] In modern semiconductor manufacturing, wafer transport robots play a crucial role. As semiconductor process nodes continue to shrink and wafer sizes continue to increase, the requirements for transport systems become increasingly stringent. Typical wafer transport scenarios include: 1) transport between wafer pods (FOUP / POD) and process equipment; 2) wafer handover within vacuum chambers; 3) wafer transfer between multiple process modules; and 4) wafer handling at inspection / measurement stations. These transport processes require high-speed, high-precision, and high-cleanliness operations within highly confined spaces (typically with only millimeter-level margins). The spatial structure further increases the risk of motion interference.

[0003] Therefore, improving transportation safety has the following advantages:

[0004] I. Preventing physical damage to wafers and ensuring yield; a) High value and fragility of wafers: Semiconductor wafers (especially large wafers of 300mm and above) are made of high-purity silicon and have low mechanical strength. Even slight impacts or vibrations can cause microcracks, edge breakage, or surface scratches, directly affecting chip yield. b) Contamination risk: Impacts can lead to particle contamination. In nanoscale processes (such as 3nm / 2nm), even micron-sized particles can cause device failure. c) Economic impact: The manufacturing cost of a 300mm wafer can reach thousands of dollars. If an entire wafer is scrapped due to an impact, the loss is enormous.

[0005] II. Avoid equipment damage and reduce maintenance costs; a) Vulnerability of precision equipment: Semiconductor manufacturing equipment (such as lithography machines and etching cavities) has a precise internal structure. Collisions between the robotic arm and the cavity, sensor or other mechanical parts may cause: deformation of the robotic arm or end effector, damage to high-precision guide rails / bearings, and failure of vacuum seals (especially serious in vacuum transmission systems); b) Downtime losses: Equipment repair or replacement of parts requires production stoppage, and losses per hour can reach tens of thousands to hundreds of thousands of US dollars (such as the extremely high downtime cost of EUV lithography machines).

[0006] III. Ensure production continuity and improve efficiency; a) Collision-free trajectory = higher throughput: Optimized trajectory planning reduces unnecessary deceleration or pauses, allowing robots to operate at near-maximum speeds and improving wafer transfer efficiency (WPH, Wafers Per Hour). b) Avoid production line interruptions: Collisions can cause chain reactions, such as wafers getting stuck in the transfer path, requiring manual intervention and affecting the automation process of the entire production line.

[0007] IV. Ensuring Personnel Safety; a) Human-Robot Collaboration Risks: During equipment maintenance, debugging, or troubleshooting, engineers may need to enter the robotic arm's work area. Without reliable collision prevention measures (such as safety light curtains or emergency stop mechanisms), the high-speed moving robotic arm may cause injury to personnel. b) Vacuum / Special Environment Risks: In vacuum or inert gas environments, collisions may lead to equipment leaks, causing safety hazards (such as vacuum bursts or gas contamination).

[0008] Currently, the working space of wafers is narrow and limited. The traditional solution is to modify the size of the robot arm, thereby shortening the robot arm's range. This makes it difficult for the existing robot arm structure or range to achieve safe control during wafer transfer. Due to the increased risk of motion interference, the safety of wafer transfer is reduced. Summary of the Invention

[0009] The purpose of this invention is to provide a partitioned trajectory control method for direct-drive robotic arms operating in interference-prone environments. This invention primarily addresses working conditions involving narrow chambers and interference-prone stations, proposing a partitioned trajectory control method that significantly improves the safety and operability of wafer transfer. In this invention, the direct-drive robotic arm can maintain transfer safety and operability even in the presence of interference-prone workspaces without altering the mechanical structure or shortening the robotic arm's range.

[0010] The technical solution adopted by this invention to achieve the above objectives is: a method for zoned trajectory control of a direct-drive robot for an interference station, comprising the following steps:

[0011] By constructing obstacle avoidance zones and safety points, the fingertips and elbows of the robotic arm are prevented from touching the interference area, including the fan-shaped disk, when the robotic arm is raised, lowered, and rotated.

[0012] Based on obstacle avoidance zones and safety points, zoned trajectory planning and control are implemented: the robot arm is first controlled to rotate to the safety point of the zone, then raised and lowered to the working height, and finally rotated before performing the action to avoid entering the obstacle avoidance zone.

[0013] The construction of obstacle avoidance zones and safe points is as follows:

[0014] The safety point is set as follows: a safety position is set so that the fingers and arms of the robotic arm will not rub against the interference area including the fan-shaped disk during the lifting and lowering process. The safety position is set between the interference station and the processing chamber.

[0015] The obstacle avoidance zone is constructed as follows: For a workstation with a fan-shaped disk interference, and a space on both sides of the chamber with workstations for picking up and placing wafers, an obstacle avoidance zone is constructed, with its t-axis rotation boundary being TL and TR, and its z-axis lifting boundary being the upper part Z_up and the lower part Z_dn of the fan-shaped disk, so that when the robot rotates with its back to the fan-shaped disk, its elbow joint will not collide with the fan-shaped disk; wherein, TL and TR are two rays TL and TR centered on the origin of the robot's lifting axis.

[0016] The partitioned trajectory planning and control includes the following steps:

[0017] The platform area can be divided into multiple areas. First, determine which area the workstation to be picked up or placed is in. If it is in the first area, return to the safety point P1 of the first area. If it is in the second area, return to the safety point P2 of the second area. If it is in the nth area, return to the safety point Pn of the nth area.

[0018] The robot arm rotates to the safety point Pn in the nth region. After the lifting axis rises to the workstation height, it rotates to the alignment position of the workstation to ensure that the robot arm is above the fan-shaped disk when rotating. Then the telescopic axis extends and retracts to complete the film picking or placing action. After completing the action, it rotates to the safety point Pn at the same height, and the lifting axis descends to the machine origin.

[0019] If the transmission trajectory is from region a to region b, the transmission trajectory first reaches the safety point Pa in region a, then rotates from the safety point Pa in region a to the safety point Pb in region b while maintaining the height of the mechanical origin. After reaching the safety point Pb in region b, it rises to the height of the designated workstation, and the height of the transmission trajectory is outside the obstacle avoidance zone of the lifting axis; otherwise, an alarm is triggered. After rising to the height of the designated workstation in region b, it maintains this height and rotates to align with the right half of the area for picking up and placing wafers. Here, a and b are natural numbers between 1 and n, and b is greater than a.

[0020] If the transmission trajectory is from region b to region a, the transmission trajectory first reaches the safety point Pb in region b, then maintains the height of the mechanical origin and rotates from the safety point Pb in region b to the safety point Pa in region a. After reaching the safety point Pa in region a, it rises to the height of the designated workstation, and the height of the transmission trajectory is outside the obstacle avoidance zone of the lifting axis; otherwise, an alarm is triggered. After rising to the height of the designated workstation in region a, it maintains this height and rotates to align with the pick-and-place workstation in region a. Here, a and b are natural numbers between 1 and n, with b being greater than a.

[0021] The present invention has the following beneficial effects and advantages:

[0022] (1) This invention addresses direct-drive robotic arms with interference zones in their motion areas by designing a safe and collision-resistant zoned trajectory control method through a combination of setting safety points and obstacle avoidance zones. Traditional solutions for interference-prone workstations involve modifying the robotic arm's dimensions to shorten its range. Compared to traditional technologies, this invention ensures both a high range for the robotic arm and increased stability, thereby extending its service life.

[0023] (2) This invention proposes a partitioned trajectory control method for a direct-drive manipulator with an interference zone in its motion area. By combining obstacle avoidance zones and safety points with partitioned trajectory planning and control, the safety and operability of semiconductor manufacturing processes in interference stations and compact chambers can be significantly improved.

[0024] (3) This invention provides a trajectory control method with an interference region, which improves the safety of wafer transmission during operation in the interference region and effectively avoids collisions. It expands the application scenarios of the robot and ensures that the scope of use is maximized. Attached Figure Description

[0025] Figure 1 Schematic diagram of the chamber environment;

[0026] Figure 2 Example diagram of a safe point;

[0027] Figure 3 Example diagram of split zone and obstacle avoidance zone. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0029] The present invention describes a method for zoned trajectory control of a direct-drive robot with an interference station, which mainly involves the construction of the chamber, the setting of obstacle avoidance zones and safety points, and the planning of zoned trajectories.

[0030] Specific technical solution:

[0031] I. Chamber Environment

[0032] The interference region is the area where the robotic arm might collide with its surroundings or obstacles during movement. Taking a sector-shaped disk as an example, the interference region... Figure 1 As shown: its internal space is narrow and there is interference in the disc area, so the robotic arm cannot rotate 360 ​​degrees in this space. When the robotic arm rotates at the same height as the interference disc, the end of its arm and the tip of its fingers will collide with the interference disc.

[0033] II. Setting up obstacle avoidance zones and safe points

[0034] Safety point setting: During wafer transport, if the robotic arm rises or falls, the fingertips may scrape against the fan-shaped disk. Therefore, safety points are set. These safety points serve two functions: first, they represent the robotic arm's pre-aligned position; second, they are the mandatory points along each movement, integrated with the zoned trajectory. This will be discussed in detail in the next section. Multiple safety points can be set. Figure 2 Taking the chamber as an example, for the fan-shaped disk area, and with wafer pick-up and drop stations on both sides of the chamber, the following two safety points (P1 and P2) can be set. Taking P1 as an example, the coordinates of the robot are as follows: its telescopic axis and lifting axis are both at the mechanical origin, and the joint value of the rotation axis is the safety value P1 that can be set by the user.

[0035] Obstacle avoidance zone settings: The obstacle avoidance zone is divided into a rotary axis obstacle avoidance zone and a lifting axis obstacle avoidance zone, such as... Figure 3 As shown, when the robotic arm rotates away from the sector-shaped disk, its elbow joint may collide with the circular tray. Therefore, the robotic arm cannot rotate within the area bounded by TL and TR. Thus, the rotation axis thresholds for the obstacle avoidance zone are TL and TR. Since the interference zone of the sector-shaped disk has a certain thickness, there is a risk of collision when the robotic arm moves at the same height as the disk area. It is safe to move only in the upper and lower parts of the disk area. Therefore, a lifting axis threshold needs to be set for the obstacle avoidance zone. The threshold is determined by Z_up and Z_dn. Multiple obstacle avoidance zones can also be set. When the robotic arm moves according to communication commands, if it forcibly moves into this area, the robotic arm will alarm and stop moving. It can only leave the area manually by operating the hand controller.

[0036] III. Zonal Trajectory Planning and Control

[0037] During wafer transport, the robotic arm's rising or falling motion can cause the wafer tip to rub against the fan-shaped disk if there is a wafer on its fingers. Therefore, lifting and rotating movements cannot be performed directly in the circular area when picking up or placing wafers. This method designs a motion trajectory that starts from a safety point and proceeds to the workstation for picking up or placing wafers. To facilitate returning to the safety point after most actions are completed, the platform area can be divided into multiple zones. First, it determines which zone the workstation is in. If it is in zone 1, it returns to the safety point P1 in zone 1; if it is in zone 2, it returns to the safety point P2 in zone 2. Figure 3Taking the chamber as an example, it is divided into two zones, defined by TA° (the dividing line can be set independently). Zone 1 is from TL° to TA°, and Zone 2 is from TA° to TR°. After zoning, when the robot arm transfers between the two workstations, it cannot directly rotate or lift to the next workstation. If working in Zone 1, it must first rotate to the safety point of Zone 1, then lift and lower the Z-axis to the workstation height before rotating to the aligned position of the workstation. This operation ensures that the robot arm is above the circular area during rotation. The telescopic axis then reaches out to pick up or place the film. After picking up or placing the film, it must maintain the same height and rotate to the safety point T-axis position before lowering the lifting axis back to the machine origin. If transferring from Zone 1 to Zone 2, the transfer trajectory is as follows: first, reach the safety point of Zone 1, then rotate from the safety point of Zone 1 to the safety point of Zone 2 while maintaining the height of the machine origin. After reaching the safety point of Zone 2, it will then rise to the height of the designated workstation. The height planned for the above trajectory must be outside the Z-axis obstacle avoidance zone; otherwise, an alarm will sound. After raising to the designated height of the second zone station, maintain that height and rotate to align with the right second zone film pick-up and drop station.

[0038] like Figure 2 In a cavity containing a sector-shaped disk interference region, the robot arm can be used in the following scenarios:

[0039] (R - telescopic axis, T - rotary axis, Z - lifting axis)

[0040] 1. The process of retrieving the film from area 1 will execute the following steps in sequence:

[0041] (1) Rotate the T-axis to the safe point P1 in zone 1;

[0042] (2) The Z-axis rises to the low position of the target wafer picking station;

[0043] (3) Keep the Z-axis at a low position while rotating the T-axis to align with the target workstation;

[0044] (4) The R-axis extends to the target workstation position;

[0045] (5) The Z-axis rises to the high position of the wafer;

[0046] (6) The R-axis retracts back to the mechanical origin of the robot arm;

[0047] (7) Keep the Z-axis at the high position of the slice, and rotate the T-axis back to the safe point P1 position in zone 1;

[0048] (8) The Z-axis descends back to the machine origin, and the film picking action ends.

[0049] II. After the film is played in area 1, the following steps will be executed in sequence:

[0050] (1) Rotate the T-axis to the safe point P1 in zone 1;

[0051] (2) The Z-axis rises to the high position of the target placement station;

[0052] (3) Maintain the high position of the lifting shaft for film placement, and rotate the T-axis to face the target film placement position;

[0053] (4) The R-axis extends to the target placement station;

[0054] (5) The Z-axis descends to the lowest position of the film placement;

[0055] (6) The R-axis retracts back to the machine origin;

[0056] (7) Rotate the T-axis back to the safe point P1;

[0057] (8) The Z-axis descends back to the Z-axis mechanical origin, and the film unloading action ends.

[0058] 3. After retrieving the film from the workstation in Zone 1, proceed to the workstation in Zone 2 to place the film:

[0059] (1) Safety point P1 in the left half of the T-axis rotation zone;

[0060] (2) The Z-axis rises to the low position of the target wafer picking station;

[0061] (3) Keep the Z-axis at the low position of the wafer picking position, rotate the T-axis, and face the target wafer picking position of Zone 1.

[0062] (4) The R-axis extends to the target workstation;

[0063] (5) The Z-axis rises to the high position of the wafer;

[0064] (6) The R-axis retracts back to the machine origin;

[0065] (7) Rotate the T-axis back to the safe point P1 in zone 1;

[0066] (8) The Z-axis descends back to the machine origin position, and the wafer picking action ends;

[0067] (9) The T-axis rotates from the first safety point P1 to the second safety point P2 while maintaining the mechanical origin height;

[0068] (10) The Z-axis is raised to the high position of the target placement station;

[0069] (11) Maintain the Z-axis high position for film placement, rotate the T-axis, and face the target film placement station in Zone 2;

[0070] (12) The R-axis extends to the target placement station;

[0071] (13) The Z-axis descends to the lowest position of the film placement;

[0072] (14) The R-axis retracts back to the machine origin;

[0073] (15) Rotate the T-axis back to the safe point P2;

[0074] (16) The Z-axis falls back to the Z-axis mechanical origin, and the film loading action ends.

Claims

1. A method for zoned trajectory control of a direct-drive robot for an interference station, characterized in that, Includes the following steps: By constructing obstacle avoidance zones and safety points, the fingertips and elbows of the robotic arm are prevented from touching the interference area, including the fan-shaped disk, when the robotic arm is raised, lowered, and rotated. Based on obstacle avoidance zones and safety points, zoned trajectory planning and control are implemented: the robot arm is first controlled to rotate to the safety point of the zone, then raised and lowered to the working height, and finally rotated before performing the action to avoid entering the obstacle avoidance zone.

2. The method for zoned trajectory control of a direct-drive robot for an interference station according to claim 1, characterized in that, The construction of obstacle avoidance zones and safe points is as follows: The safety point is set as follows: a safety position is set so that the fingers and arms of the robotic arm will not rub against the interference area including the fan-shaped disk during the lifting and lowering process. The safety position is set between the interference station and the processing chamber. The obstacle avoidance zone is constructed as follows: For a workstation with a fan-shaped disk interference, and a space on both sides of the chamber with workstations for picking up and placing wafers, an obstacle avoidance zone is constructed. Its rotation axis boundaries are TL and TR, and the lifting axis boundaries are the upper part Z_up and the lower part Z_dn of the fan-shaped disk, so that when the robot rotates with its back to the fan-shaped disk, its elbow joint will not collide with the fan-shaped disk; wherein, TL and TR are two rays TL and TR centered on the origin of the robot's lifting axis.

3. The partitioned trajectory control method for a direct-drive robot at an interference station according to claim 1, characterized in that, The partitioned trajectory planning and control includes the following steps: The platform area is divided into multiple areas. First, it is determined which area the workstation to be picked up and placed is in. If it is in the first area, it returns to the safety point P1 of the first area. If it is in the second area, it returns to the safety point P2 of the second area. If it is in the nth area, it returns to the safety point Pn of the nth area. The robot arm rotates to the safety point Pn in the nth region. After the lifting axis rises to the workstation height, it rotates to the alignment position of the workstation to ensure that the robot arm is above the fan-shaped disk when rotating. Then the telescopic axis extends and retracts to complete the film picking or placing action. After completing the action, it rotates to the safety point Pn while maintaining the same height, and then the lifting axis descends to the machine origin.

4. A method for zoned trajectory control of a direct-drive robot for an interference station according to claim 1 or 3, characterized in that, If the transmission trajectory is from region a to region b, the transmission trajectory first reaches the safety point Pa in region a, then maintains the height of the mechanical origin and rotates from the safety point Pa in region a to the safety point Pb in region b. After reaching the right safety point Pb, it rises to the height of the designated workstation, and the height of the transmission trajectory is outside the obstacle avoidance zone of the lifting axis; otherwise, an alarm is triggered. After rising to the height of the designated workstation in region b, it maintains this height and rotates to align with the pick-and-place workstation in region b. Here, a and b are natural numbers between 1 and n, and b is greater than a.

5. A method for zoned trajectory control of a direct-drive robot for an interference station according to claim 1 or 3, characterized in that, If the transmission trajectory is from region b to region a, the transmission trajectory first reaches the safety point Pb in region b, then maintains the height of the mechanical origin and rotates from the right safety point Pb to the left safety point Pa. After reaching the left safety point Pa, it rises to the height of the designated station, and the height of the transmission trajectory is outside the obstacle avoidance zone of the lifting axis; otherwise, an alarm is triggered. After rising to the height of the designated station in region a, it maintains this height and rotates to align with the pick-and-place station in region a. Here, a and b are natural numbers between 1 and n, and b is greater than a.

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