Wafer transfer device with liquid discharging function

Abstract

Disclosed in the present invention is a wafer transfer device with a liquid discharging function, the wafer transfer device comprising a robot arm, a liquid receiving device, a liquid discharging device, a controller and a collecting bin, wherein the liquid receiving device is arranged below the robot arm and moves along with the robot arm so as to receive liquid dripping from the robot arm; the liquid discharging device comprises a liquid discharging pipeline and a control valve, the liquid discharging pipeline being connected to the liquid receiving device, and the control valve being arranged on the liquid discharging pipeline and configured to control the connection and disconnection of the liquid discharging pipeline; the controller is in communication with both the robot arm and the control valve, and is configured to control the movement of the robot arm and the opening and closing of the control valve; and the collecting bin is located at a predetermined liquid discharging position. When the liquid level of liquid in the liquid receiving device reaches a preset liquid level, the controller firstly controls the robot arm to move to the predetermined liquid discharging position, and then controls the control valve to open, and thus the liquid in the liquid receiving device is discharged into the collecting bin through the liquid discharging pipeline. The present invention can control the storage and discharge of liquid in the liquid receiving device, and does not limit the motion of the robot arm and thus does not influence the normal process time of the robot arm.

Description

Wafer transfer device with liquid discharge function Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a wafer transmission device with a liquid discharge function. Background Art

[0002] During wafer transfer, a wafer transfer robot is used to move wafers between various workstations. Some workstations require wafer cleaning to remove dust, residue, and dirt. After cleaning, a film of liquid forms on the wafer surface. During wafer transfer, this liquid can drip onto the robot, which can then drip into semiconductor equipment and cause contamination.

[0003] At present, the liquid receiving device of the robot arm in semiconductor equipment is mainly used to receive the liquid dripping from the robot arm. A drain port and a drain pipe are set at the bottom of the liquid receiving device, and the liquid outlet end of the drain pipe is placed in a fixed drain tank so that the drain pipe can continuously drain the liquid during the operation of the robot arm. In order to ensure the normal operation of the robot arm, it is necessary to ensure that the liquid in the liquid receiving device can always be discharged normally. However, in order to ensure that the liquid outlet end of the drain pipe is always placed in the drain tank, the drain pipe is usually set to be longer, which will have certain restrictions on the movement of the robot arm (such as rotation, horizontal and lifting movement). This is because during the movement of the robot arm (such as rotation, horizontal and lifting movement), the drainage pipe often becomes damaged, entangled or interferes with other components. This situation will cause abnormal drainage of the liquid receiving device, thereby affecting the normal process of the robot arm.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to solve the problem in the prior art that the liquid receiving device restricts the movement of the robot arm and affects the normal processing time of the robot arm.

[0006] To solve the above problems, one embodiment of the present invention provides a wafer transfer device with a liquid discharge function, comprising:

[0007] Robotic arm;

[0008] The liquid receiving device is arranged under the robot arm and moves with the robot arm to receive and store the liquid dripping from the robot arm;

[0009] The liquid discharge device includes a liquid discharge pipeline and a control valve. The liquid discharge pipeline is connected to the liquid receiving device. The control valve is arranged on the liquid discharge pipeline to control the on-off of the liquid discharge pipeline.

[0010] a controller, in communication with the robot arm and the control valve, for controlling the movement of the robot arm and the opening and closing of the control valve; and

[0011] a collection chamber located at a predetermined discharge position;

[0012] When the liquid level in the liquid receiving device reaches a preset level, the controller first controls the robot arm to move to a predetermined discharge position, and then controls the control valve to open, so that the discharge pipeline discharges the liquid in the liquid receiving device to the collection bin.

[0013] The wafer transfer device with liquid discharge function provided by the present invention includes a robot arm, a liquid receiving device, a liquid discharge device, a controller and a collection bin. When the robot arm is operating normally, the controller controls the control valve to close so that the liquid receiving device receives and stores the liquid dripping from the robot arm; when the liquid stored in the liquid receiving device reaches a preset liquid level, the controller first controls the robot arm to move to a predetermined liquid discharge position, so that the liquid discharge device is close to and aligned with the collection bin, and then controls the control valve to open so that the liquid in the liquid receiving device is discharged from the liquid discharge pipeline to the collection bin. Because the present application controls the liquid discharge device to discharge liquid at a predetermined liquid discharge position, it is beneficial to shorten the length of the liquid discharge pipeline, and can avoid the liquid discharge pipeline being too long and being damaged, entangled or interfering with other surrounding components when the robot arm is lifted or moved horizontally. Therefore, the present application can control the storage and discharge of liquid in the liquid receiving device without restricting the movement of the robot arm, thereby not affecting the normal process time of the robot arm.

[0014] Other features and corresponding beneficial effects of the present invention are described in the latter part of the specification, and it should be understood that at least some of the beneficial effects become obvious from the description in the specification of the present invention.

[0015] Summary of the Figures

[0016] The features and properties of the present invention are further described by the following examples and accompanying drawings.

[0017] FIG1 is a schematic front view of a wafer transfer device with a liquid discharge function provided by the present invention;

[0018] FIG2 is a schematic cross-sectional view along section line UU in FIG1 ;

[0019] FIG3 is a schematic diagram of a partial three-dimensional structure of a wafer transfer device with a liquid discharge function provided by the present invention;

[0020] FIG4 is a partial schematic diagram of portion F in FIG1 ; and

[0021] FIG5 is a partial cross-sectional schematic diagram of a wafer transfer device with a liquid discharge function provided by the present invention.

[0022] Preferred embodiments of the present invention

[0023] The following is an explanation of the embodiments of the present invention by specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this embodiment. On the contrary, the purpose of introducing the invention in conjunction with the embodiment is to cover other options or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will contain many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0024] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0028] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0029] The wafer transfer device with liquid discharge function of the present application can be set in a semiconductor device, which includes a wafer loading platform and multiple process chambers. The wafer loading platform is used to place a transfer box, which stores wafers to be cleaned and wafers that have been cleaned. The process chamber is used to brush away dust, residue, dirt, etc. on the wafer.

[0030] In conjunction with Figures 1 to 3 , Figure 1 is a schematic front view of a wafer transfer device with a liquid discharge function provided by the present invention; Figure 2 is a schematic cross-sectional view taken along section line UU in Figure 1 ; and Figure 3 is a schematic diagram of a partial three-dimensional structure of a wafer transfer device with a liquid discharge function provided by the present invention. For ease of presentation, the coordinate axes are labeled in Figure 1 : the Y-axis represents the vertical direction of motion H, and the X-axis represents the horizontal direction of motion L.

[0031] As shown in Figures 1 and 2, the wafer transfer device with liquid discharge function of the present application includes a vertical guide rail 110, a horizontal guide rail 120, a mounting platform 130, a robot 200, a liquid receiving device 300, a liquid discharge device 400, a collection chamber 500, and a controller. The robot 200 is rotatably mounted on the mounting platform 130 via a rotating shaft 210. The mounting platform 130 is mounted on the vertical guide rail 110 and is used to perform lifting and lowering motion on the vertical guide rail 110 along a vertical motion direction H. A horizontal mounting portion 111 is fixedly provided on the vertical guide rail 110. The horizontal mounting portion 111 is slidably connected to the horizontal guide rail 120. The vertical guide rail 110 is horizontally moved on the horizontal guide rail 120 along a horizontal motion direction L via the horizontal mounting portion 111. The horizontal guide rail 120 is located at a position where the coordinate of the robot 200 in the vertical motion direction H is zero. As shown in Figure 3, the robot 200 includes a conveying arm 221 and an end effector 222. The conveying arm 221 is fixedly connected to the rotating shaft 210 and is used to rotate around the axis of the rotating shaft 210. The end effector 222 is fixed to the end of the conveying arm 221 and is used to take and place wafers from a transfer box or a process chamber.

[0032] As shown in Figure 3, liquid receiving device 300 is located below robot arm 200 and moves with robot arm 200. Liquid receiving device 300 is used to receive and store liquid dripping from robot arm 200, preventing it from dripping into semiconductor equipment and causing contamination. Liquid on robot arm 200 primarily comes from liquid on wafers before or after cleaning.

[0033] The drainage device 400 includes a drainage pipeline 410, a control valve 420, and a mounting base 430. The drainage pipeline 410 is connected to the liquid receiving device 300 and is used to discharge the liquid in the liquid receiving device 300 into the collection chamber 500. The control valve 420 is disposed in the drainage pipeline 410 and fixed to the mounting base 430, which is fixed to the mounting platform 130. The controller is in communication with the control valve 420 and is used to control the opening and closing of the drainage pipeline 410. The control valve 420 can be a solenoid valve, and the drainage pipeline 410 can be a hose.

[0034] The collection bin 500 is fixed below the horizontal guide rail 120. The location of the collection bin 500 can be considered the predetermined drainage location. A discharge outlet 510 is provided at the bottom of the collection bin 500, which is connected to the factory wastewater treatment system. When the drainage device 400 is discharging liquid, it aligns with the collection bin 500 to discharge the liquid into the collection bin 500.

[0035] To address the issue of abnormal drainage during robot operation in a conventional continuous drainage mode of a liquid receiving device, which affects the normal operation of the robot, the overall concept of the technical solution in the embodiments of the present application is as follows: When the robot 200 is operating normally, whether performing lifting, horizontal, or rotational motion, the controller controls the control valve 420 to close, allowing the liquid receiving device 300 to receive and store liquid dripping from the robot 200. When the liquid stored in the liquid receiving device 300 reaches a preset liquid level, the controller controls the robot 200 to move to a predetermined drainage position (e.g., the initial position of the robot 200 in FIG. 1 ), aligning the drainage device 400 with the collection bin 500, and then controls the control valve 420 to open, allowing the liquid in the liquid receiving device 300 to be discharged from the drainage pipe 410 to the collection bin 500. Therefore, the drainage device 400 can control the storage and drainage of liquid in the liquid receiving device 300 without restricting the movement of the robot 200, thereby not affecting the normal processing time of the robot 200. The predetermined drain position can preferably be a position where the coordinate in the vertical direction H of the robot 200 is zero and the coordinate in the horizontal direction L of the robot 200 is zero (for example, the initial position of the robot 200). This helps shorten the length of the drain line 410. The drain line 410 only needs to be long enough to properly drain the liquid to the collection bin 500, so as to avoid the drain line 410 being too long and interfering with other surrounding components when the robot 200 is raised or lowered or moved horizontally. It should also be noted that when the liquid receiving device 300 needs to drain, if the current process cycle has not yet ended, the controller controls the robot 200 to complete the current process cycle first and then move to the predetermined drain position.

[0036] When the liquid receiving device 300 needs to drain, the collection chamber 500 is configured to extend along the horizontal motion direction L of the robot 200, that is, along the horizontal guide rail 120, to shorten the travel distance required for the robot arm 200 to reach the predetermined drain position. Because the collection chamber 500 extends along the horizontal motion direction L of the robot arm 200, it can receive liquid discharged from the drain pipe 410 at any position of the robot arm 200 in the horizontal motion direction L. The predetermined drain position can be set to any coordinate position of the robot arm 200 in the horizontal motion direction L when the coordinate in the vertical motion direction H of the robot arm 200 is zero. Therefore, when the liquid in the liquid receiving device 300 needs to be drained, the controller controls the robot arm 200 to complete the current process cycle and then return to the zero position of the vertical guide rail 110 to complete the drain. This shortens the travel distance required for the robot arm 200 to reach the predetermined drain position compared to setting the predetermined drain position only at the initial position of the robot arm 200.

[0037] In addition, when the drainage pipe 410 discharges liquid, the liquid outlet of the drainage pipe 410 is within the opening range of the collection bin 500, so that the liquid can be discharged into the collection bin 500, reducing the alignment accuracy requirements of the drainage pipe 410 and the collection bin 500.

[0038] In the present application, when the liquid in the liquid receiving device 300 needs to be discharged can be known by setting a liquid level monitor to detect the liquid level of the liquid receiving device 300. The design position and working principle of the liquid level monitor are described in detail below.

[0039] 3 to 5 , the liquid receiving device 300 includes a residual liquid tray 310, a temporary storage tray 320, and a liquid level monitor 324. The residual liquid tray 310 is fixed on the top of the rotating shaft 210 and is arranged around the periphery of the robot arm 200. The residual liquid tray 310 rotates synchronously with the rotating shaft 210. The temporary storage tray 320 is located below the residual liquid tray 310 and is used to receive the liquid flowing down from the residual liquid tray 310. The temporary storage tray 320 is fixed to the mounting table 130 and is provided with a gap from the rotating shaft 210. When the residual liquid tray 310 rotates synchronously with the rotating shaft 210, the temporary storage tray 320 does not rotate. The liquid level monitor 324 is communicatively connected to the controller and is used to monitor the liquid level in the temporary storage tray 320 in real time. In this example, the liquid level monitor 324 may preferably adopt a non-contact liquid level sensor, which is arranged at the bottom of the residual liquid tray 310, such as a laser sensor or an acoustic liquid level sensor. It is understood that, in other examples, the liquid level monitor 324 may also adopt a contact type liquid level sensor.

[0040] With reference to Figure 3 , the residual liquid tray 310 comprises a bottom wall 3101, a first side wall 3102, and a second side wall 3103. The bottom wall 3101 is fixed to the top of the rotating shaft 210. The first side wall 3102 extends obliquely upward along the outer periphery of the bottom wall 3101. The second side wall 3103 extends upward along the upper end of the first side wall 3102 and surrounds the outer side of the robotic arm 200. Referring to Figure 5 , the residual liquid tray 310 is also provided with a delivery pipe 312 connected to the bottom wall 3101 and used to transport liquid from the residual liquid tray 310 to the temporary storage tray 320. When liquid from the robotic arm 200 drips onto the first side wall 3102, it flows along the inclined surface of the first side wall 3102 to the bottom wall 3101 of the residual liquid tray 310 and is discharged to the temporary storage tray 320 through the delivery pipe 312 provided on the bottom wall 3101. In addition, the upper surface of the bottom wall 3101 of the residual liquid tray 310 is a slope, which slopes downward along the direction from the outer periphery of the bottom wall 3101 to the center of the bottom wall 3101, and the delivery pipe 312 is preferentially connected to the lowest point of the slope to facilitate the liquid in the residual liquid tray 310 to be collected and discharged to the delivery pipe 312.

[0041] 5 , the temporary storage tray 320 has a bottom wall 3201 and oppositely disposed first and second side walls 3202 and 3203, as well as a first flow channel 3221. The bottom wall 3201 of the temporary storage tray 320 is connected to the drainage pipe 410 (see FIG. 3 ).

[0042] The first sidewall 3202 of the temporary storage tray 320 is provided with a first baffle 322 to prevent the liquid in the temporary storage tray 320 from splashing out of the temporary storage tray 320 during lifting or horizontal movement. A predetermined longitudinal distance is defined between the first baffle 322 and the outlet of the delivery tube 312. The predetermined longitudinal distance is 5 mm to 10 mm, for example, 6 mm to 8 mm. The first baffle 322 extends from the first sidewall 3202 to the second sidewall 3203 and forms a first circulation channel 3221 between the first baffle 322 and the second sidewall 3203. When the liquid in the residual liquid tray 310 is discharged to the temporary storage tray 320 through the delivery tube 312, the liquid in the delivery tube 312 flows along the upper surface of the first baffle 322 and flows into the interior of the temporary storage tray 320 through the first circulation channel 3221. In other embodiments, the first circulation channel may also be a liquid outlet provided on the first baffle 322, so that the liquid on the first baffle 322 can also flow into the interior of the temporary storage tray 320 from the liquid outlet. In addition, the upper surface of the first baffle 322 is an inclined surface, which slopes downward along the first side wall 3202 toward the second side wall 3203. The liquid in the delivery pipe 312 passes through the inclined surface of the first baffle 322 and is guided to the interior of the temporary storage tray 320.

[0043] A second baffle 323 is provided on the second sidewall 3203 of the temporary storage tray 320 to block liquid splashing back onto the first baffle 322 or within the temporary storage tray 320. The second baffle 323 extends from the second sidewall 3203 toward the first sidewall 3202, forming a gap 3231 between the second baffle 323 and the first sidewall 3202. When the residual liquid tray 310 rotates synchronously with the rotation shaft 210, the outlet end of the delivery tube 312 moves within the gap 3231. The second baffle 323 is spaced above the first baffle 322, and the outlet of the delivery tube 312 is no higher than the second baffle 323. This prevents liquid delivered from the delivery tube 312 from being flung away when the residual liquid tray 310 and delivery tube 312 rotate.

[0044] Specifically, the upper surface of the second baffle 323 can also be a slope, which slopes downward along the second side wall 3203 toward the first side wall 3202, so that the liquid splashing onto the upper surface of the second baffle 323 can be diverted to the inside of the temporary storage disk 320.

[0045] The working principle of the liquid discharge device when the liquid level monitor 324 is configured will be described below in conjunction with the above description and FIG. 3 to FIG. 5 .

[0046] When the robotic arm 200 is operating normally, the controller controls the control valve 420 to close, causing the liquid on the robotic arm 200 to drip onto the residual liquid tray 310. The liquid in the residual liquid tray 310 can then flow to the temporary storage tray 320 via the delivery pipe 312 at any time. When the liquid level of the temporary storage tray 320 monitored by the liquid level monitor 324 is lower than a preset level, the liquid level monitor 324 is not triggered, and the robotic arm 200 can move up and down, horizontally, or rotate. When the liquid level of the temporary storage tray 320 reaches a preset level, the liquid level monitor 324 is triggered, where the preset level is one-quarter of the distance between the lowest point of the inclined surface of the first baffle 322 and the bottom surface of the second baffle 323. When triggered, the liquid level monitor 324 sends a drain signal. Upon receiving this drain signal, the controller controls the robot 200 to move to a predetermined drain position after completing the current process cycle. The controller then controls the control valve 420 to open, allowing the liquid in the temporary storage tray 320 to be discharged into the collection chamber 500 through the drain line 410. After draining is complete, the control valve 420 closes, and the robot 200 can proceed to the next action.

[0047] In other embodiments, other methods can be used to determine when the liquid in the temporary storage tray 320 of the liquid receiving device 300 needs to be drained. For example, if the liquid level monitor 324 is not provided, the time interval for draining the temporary storage tray 320 can be pre-set in the process operation program, so that the temporary storage tray 320 is drained once every predetermined period. During drainage, the controller controls the robot arm 200 to move to the predetermined drainage position and then controls the control valve 420 to open.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wafer transfer device with liquid discharge function, characterized in that: include: Robotic hand; A liquid receiving device, which is arranged below the robot arm and moves with the robot arm, and is used to receive and store liquid dripping from the robot arm; A liquid discharge device, comprising a liquid discharge pipeline and a control valve, wherein the liquid discharge pipeline is connected to the liquid receiving device, and the control valve is arranged on the liquid discharge pipeline to control the on-off of the liquid discharge pipeline; A controller, which is in communication with the robot arm and the control valve, and is used to control the movement of the robot arm and the opening and closing of the control valve; as well as A collection chamber located at a predetermined discharge position; When the liquid level in the liquid receiving device reaches a preset level, the controller first controls the robot arm to move to the predetermined liquid discharge position, and then controls the control valve to open, so that the liquid discharge pipeline discharges the liquid in the liquid receiving device to the collection bin.

2. The wafer transfer device with liquid discharge function according to claim 1, characterized in that: The liquid receiving device is provided with a liquid level monitor, and the liquid level monitor is communicatively connected with the controller and is used for real-time monitoring of the liquid level in the liquid receiving device.

3. The wafer transfer device with liquid discharge function according to claim 1, characterized in that: It also includes a mounting platform and a rotating shaft, and the robot arm is rotatably arranged on the mounting platform through the rotating shaft; The liquid receiving device includes a residual liquid tray and a temporary storage tray. The residual liquid tray is fixed to the rotating shaft and is arranged around the periphery of the robot arm. The temporary storage tray is arranged on the mounting table, located below the residual liquid tray, and is connected to the liquid discharge device for receiving and discharging the liquid in the residual liquid tray.

4. The wafer transfer device with liquid discharge function according to claim 3, characterized in that: The residual liquid tray also includes a delivery pipe for delivering the liquid in the residual liquid tray to the temporary storage tray.

5. The wafer transfer device with liquid discharge function according to claim 4, characterized in that: The temporary storage tray has a first side wall, a second side wall and a first flow channel opposite to each other, the first side wall is provided with a first baffle, and there is a predetermined longitudinal distance between the first baffle and the outlet of the delivery pipe; When the liquid in the residual liquid tray is discharged to the temporary storage tray through the delivery pipe, the liquid in the delivery pipe flows along the upper surface of the first baffle and flows into the temporary storage tray through the first flow channel.

6. The wafer transfer device with liquid discharge function according to claim 5, characterized in that: The predetermined longitudinal distance between the first baffle and the outlet of the delivery pipe is 5 mm to 10 mm.

7. The wafer transfer device with liquid discharge function according to claim 5, characterized in that: The first baffle extends from the first side wall to the second side wall, and forms the first flow channel between the first baffle and the second side wall.

8. The wafer transfer device with liquid discharge function according to claim 7, characterized in that: The upper surface of the first baffle is an inclined surface, and the inclined surface is inclined downward along the first side wall toward the second side wall.

9. The wafer transfer device with liquid discharge function according to claim 5, characterized in that: The second side wall of the temporary storage disk is provided with a second baffle, which extends from the second side wall to the first side wall and forms a gap with the first side wall. The second baffle is spaced above the first baffle, and the outlet of the conveying pipe is not higher than the second baffle.

10. The wafer transfer device with liquid discharge function according to claim 9, characterized in that: An upper surface of the second baffle is an inclined surface, and the inclined surface is inclined downward along the second side wall toward the first side wall.

11. The wafer transfer device with liquid discharge function according to claim 1, characterized in that: Also includes: A vertical guide rail, on which the robot arm is slidably connected, so that the robot arm moves vertically along the vertical guide rail; and A horizontal guide rail is slidably connected to the vertical guide rail so that the vertical guide rail carries the robot arm to move horizontally along the horizontal guide rail.

12. The wafer transfer device with liquid discharge function according to claim 11, characterized in that: The predetermined discharge position is a position where the coordinate in the vertical movement direction of the robot arm is zero and the coordinate in the horizontal movement direction of the robot arm is zero.

13. The wafer transfer device with liquid discharge function according to claim 11, characterized in that: The predetermined discharge position is any coordinate position in the horizontal movement direction of the robot arm when the coordinate in the vertical movement direction of the robot arm is zero.

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