Wafer transfer detection method

Abstract

The application discloses a wafer transmission detection method, comprising the following steps: the bottom plate and the back plate are turned over at an angle; the moving clamp on the bottom plate is matched with the supporting structure to horizontally clamp the wafer, at this time, the moving clamp has a first extension stroke; the first extension stroke is compared with a preset value to determine whether the moving clamp correctly clamps the wafer; after the moving clamp correctly clamps the wafer, the bottom plate is turned over to a vertical state, and the supporting structure vertically supports the wafer; the back plate is moved downward by an X stroke, the wafer is moved downward and falls into the wafer holder, and then abuts against the moving clamp to push the moving clamp to have a second extension stroke; the X stroke is compared with a target value to determine whether the wafer is vertically placed in the wafer holder. The application simplifies the detection structure and detection process of whether the wafer is vertically placed, and the detection result is more accurate; the real-time detection of the wafer in the movement process is realized, and the detection adaptability is higher; meanwhile, the wafer detection of the vertical and horizontal placement of the wafer is realized, and the detection structure is relatively optimal.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor integrated circuit chip manufacturing technology, and in particular relates to a wafer transfer detection method. Background Technology

[0002] Wafers are typically transported using grippers on robotic arms. This requires the wafers to be placed horizontally and securely at the workstation; otherwise, the robotic arm may fail to pick up the wafer, interrupting the entire machine's operation and resulting in losses of time and money. Therefore, the wafer workstation needs a device to detect whether the wafer is placed horizontally, and also a device to detect the presence or absence of wafers in real time.

[0003] Previously, wafer leveling was determined by two sets of opposing laser sensors positioned around the wafer workstation, aligning them cross-shaped to the wafer surface. If the wafer was not level, at least one set of sensors would be blocked, thus detecting whether the wafer was level. Now, wafer presence is determined by another set of sensors positioned above and below the wafer. When no wafer is present, the sensors receive a signal; when a wafer is present, it blocks the laser path, preventing the sensors from receiving a signal. This method has several drawbacks: 1) It's complex, requiring three sets of sensors and six small devices to be arranged around the wafer, consuming significant space and involving numerous wiring connections; 2) Laser sensor calibration requires aligning the transmitter and receiver, but the limited space makes manual adjustment difficult; 3) Over time, loose screws or other factors can cause sensor position changes, leading to misalignment of the transmitter and receiver, necessitating readjustment. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a wafer transfer detection method that can be applied to movable flip-over base plates and back plates. It has a simple structure and provides accurate and effective detection.

[0005] The technical solution adopted by this invention to solve its technical problem is: a wafer transfer detection method, comprising the following steps: The bottom and back plates are flipped at an angle. The movable gripper and support structure on the flip base plate cooperate to horizontally clamp the wafer, at which time the movable gripper has a first extension stroke; The first extension stroke is compared with a preset value to determine whether the moving gripper is correctly gripping the wafer; After the moving grippers correctly clamp the wafer, the flip plate flips to a vertical position, and the support structure vertically supports the wafer. The backplate moves down X stroke, and after the wafer falls into the wafer holder, it abuts against the moving jaws to push the moving jaws to have a second extension stroke; The X-stroke is compared with the target value to determine whether the wafer is placed vertically on the wafer holder.

[0006] Furthermore, the process includes the following steps: after the wafer is placed vertically on the wafer holder, the base plate is flipped and rotated relative to the back plate to detach the wafer.

[0007] Furthermore, in the step where the moving gripper correctly clamps the wafer, the flip base plate flips to a vertical state, and the support structure vertically supports the wafer, the moving gripper changes from state one of clamping the wafer to state two of limiting the wafer.

[0008] Furthermore, during the X-stroke downward movement of the backplate, after the wafer falls into the wafer holder, it abuts against the movable gripper to push the movable gripper to the step of having a second extension stroke. If the movable gripper has a first extension stroke, it is determined that the wafer is not placed vertically on the wafer holder.

[0009] Furthermore, after the wafer is placed vertically in the wafer holder, the flip base plate rotates relative to the back plate to detach the wafer. In this step, the moving gripper is reset to its initial zero point, and the flip base plate rotates relative to the back plate again.

[0010] Furthermore, in the step of comparing the first extension stroke with a preset value to determine whether the moving gripper is correctly gripping the wafer, if the moving gripper is not correctly gripping the wafer, a warning signal is issued and subsequent steps are stopped.

[0011] Furthermore, the movable gripper includes a gripper portion, an air chamber into which one end of the gripper portion extends, and at least two air ports, which are located on both sides of the gripper portion respectively; when the movable gripper has a first extension stroke, air enters through the air port on the first side of the gripper portion; when the movable gripper is converted to the second state of limiting the wafer, air does not enter through the air ports on both sides of the gripper portion.

[0012] Furthermore, when the moving gripper has a second extension stroke, air does not enter through the air ports on both sides of the gripper.

[0013] Furthermore, as the moving gripper retracts to its initial zero point, air enters through the second side air inlet of the gripper.

[0014] Furthermore, the rotation angle of the flip-over base plate relative to the back plate is 2-10°.

[0015] Furthermore, in the step of comparing the first extension stroke with a preset value to determine whether the moving gripper is correctly gripping the wafer, if the first extension stroke is equal to the preset value or the difference is less than a first threshold, then it is determined that the moving gripper is correctly gripping the wafer. In the step of comparing the X-stroke with the target value to determine whether the wafer is placed vertically in the wafer holder, if the X-stroke is equal to the target value or the difference is less than the second threshold, then it is determined that the wafer is placed vertically in the wafer holder.

[0016] The beneficial effects of this invention are: 1) It simplifies the detection structure and process for determining whether a wafer is placed vertically, resulting in more accurate detection results; 2) It enables real-time detection of wafers during movement, providing greater adaptability; 3) It simultaneously enables wafer detection for both vertical and horizontal placement, resulting in a superior detection structure; 4) It can detect both wafer placement and detachment, simplifying the structure while providing comprehensive functionality; 5) It eliminates the need for multiple sensor sets, saving costs and facilitating debugging. Attached Figure Description

[0017] Figure 1 This is a perspective view of the wafer transfer device in this invention, where the flip-top plate is in its first working state.

[0018] Figure 2 This is a perspective view of the wafer transfer device in this invention, where the flip-top plate is in the second working state.

[0019] Figure 3 This is a front view of the movable gripper in this invention.

[0020] Figure 4 for Figure 3 FF section view in the image.

[0021] Figure 5 This is a simplified diagram showing the moving position and travel of the right end of the claw in this invention.

[0022] Figure 6 This is a three-dimensional structural diagram of the support structure in this invention.

[0023] Figure 7 This is a top view of the box structure in this invention.

[0024] Figure 8 This is a three-dimensional structural diagram of the chemical mechanical planarization device in this invention.

[0025] Figure 9 This is a top view of the chemical mechanical planarization device in this invention.

[0026] Figure 10 This is a top view of the housing in this invention.

[0027] Figure 11 for Figure 10 DD section view in the image. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions in 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 a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] A wafer transfer device includes a back plate 11 and a flip base plate 12 rotatably connected to the back plate 11 via a pivot 17. The flip base plate 12 is provided with a wafer holder 13 for clamping a wafer 2. The pivot 17 is located at the lower end of the back plate 11. Of course, in other embodiments, the rotatable connection between the back plate 11 and the flip base plate 12 can be achieved without the pivot 17, but through other structures in the prior art.

[0030] like Figure 1 , Figure 2 As shown, the flip base plate 12 has a first working state and a second working state. In the first working state, the flip base plate 12 forms an angle with the back plate 11, so that the wafer holder 13 can horizontally clamp the wafer 2. In this embodiment, the angle is 90°. Of course, in other embodiments, the angle may not be 90°, or the wafer holder 13 may clamp the wafer 2 in a more horizontal manner.

[0031] In the second working state, the flip base plate 12 rotates relative to the back plate 11 until the wafer 2 is in a vertical state. At this time, the flip base plate 12 and the back plate 11 can be parallel to each other. The vertical state here does not necessarily mean that it is completely perpendicular to the ground, but it can also be close to perpendicular.

[0032] Whether in the first working state or the second working state, the wafer 2 held by the wafer holder 13 is parallel to the flip base plate 12.

[0033] The back plate 11 can move up and down. When the flip-down base plate 12 is in the second working state, it can move up and down along with the back plate 11. Specifically, the back plate 11 cooperates with the sliding rail 16, which can be installed in the top opening of the housing 3.

[0034] like Figure 7 As shown, a wafer holder 33 is provided inside the housing 3 to support the vertical wafers 2 on the flip base plate 12. There may be one, two, or more wafer holders 33. When there are two wafer holders 33, one receives the wafers 2 from the flip base plate 12, while the other can remain to the side, supporting wafers 2 and awaiting transfer; alternatively, the other can remain to the side without supporting any wafers. The specific configuration is not limited. The two wafer holders 33 can move synchronously or be controlled independently.

[0035] The wafer holder 13 includes at least two support structures 14 and a movable gripper 15. The positions of the support structures 14 are relatively fixed, and at least a portion of the movable gripper 15 is movable, so that the movable gripper 15 and the support structures 14 cooperate to clamp or release the wafer 2.

[0036] At least a portion of the movable gripper 15 here is movable, including its extension and retraction movements as well as its rotational movements, without any specific limitation.

[0037] like Figure 3 , Figure 4 As shown, the movable gripper 15 includes a gripper portion 151, an air chamber 152 into which one end of the gripper portion 151 extends, and at least two air ports, 153 and 154, located on opposite sides of the gripper portion 151. When the movable gripper 15 has a first extension stroke, air is introduced through the air port 153 on the first side of the gripper portion 151; when the movable gripper 15 is switched to state two (limiting the wafer 2), air is not introduced through either of the air ports on the sides of the gripper portion 151.

[0038] In this embodiment, the movable gripper 15 is a double-acting cylinder. The cylinder is equipped with a position sensor, which can accurately detect the position of the piston inside the cylinder in real time, that is, the position of the gripper 151. A cylinder with low thrust is selected to ensure that the wafer is not crushed.

[0039] When the movable gripper 15 has a second extension stroke, that is, when the right end of the movable gripper 15 is in the... Figure 5 At point E, air does not enter through either of the air vents on both sides of the claw 151.

[0040] When the moving jaw 15 retracts to its initial zero point, that is, when the right end of the moving jaw 15 is at... Figure 5 At point B, air enters through the second side air inlet 154 of the claw 151.

[0041] like Figure 6 As shown, the support structure 14 includes a body 141 connected to the flip base plate 12, a first inclined surface 142 disposed on the body 141, and a second inclined surface 143 flared out from the first inclined surface 142. The first inclined surface 142 is inclined from top to bottom and from outside to inside. The wafer 2 is placed on the first inclined surface 142. The second inclined surface 143 cooperates with the first inclined surface 142 to clamp the wafer 2, so that the upper and lower side edges of the wafer 2 contact the second inclined surface 143 and the first inclined surface 142 respectively, thereby reducing the contact area between the support structure 14 and the wafer 2 and avoiding damage to the surface of the wafer 2.

[0042] The support structure 14 also includes a third inclined surface 144, which forms an angle with the second inclined surface 143 and slopes downwards and inwards with a large slope, serving as a guide to guide the wafer 2 to be clamped between the first inclined surface 142 and the second inclined surface 143. The first inclined surface 142 and the second inclined surface 143 can be directly connected, or a groove 145 can be provided between them.

[0043] In other words, wafer 2 can slide down the third inclined plane 144 onto the first inclined plane 142, and then, through the extension and compression or rotation of the moving gripper 15, wafer 2 moves against the first inclined plane 142 and the second inclined plane 143 until the sidewall contacts or approaches the groove 145.

[0044] like Figure 8 , Figure 9 As shown, a chemical mechanical planarization device includes a polishing module 4, a cleaning input module 5, and a cleaning module 6, which are arranged in sequence. The cleaning input module 5 includes a housing 3 and the aforementioned wafer transfer device.

[0045] Wafer 2 is horizontally transferred from polishing module 4 to wafer transfer device. By flipping the base plate 12, it is converted from the first working state to the second working state. Wafer 2 is converted to a vertical state and temporarily stored in the box 3, waiting for the external transfer device to transfer it to cleaning module 6. At this time, the transfer can be carried out in a vertical state to adapt to cleaning module 6.

[0046] The cleaning module 6 includes at least two rows of cleaning units 61. Each row of cleaning units 61 includes multiple cleaning boxes arranged at intervals. The box body 3 extends to both sides to form the left and right bodies corresponding to the pre-cleaning units 61. Since the wafer can move vertically to both sides of the box body 3, the width of the left and right bodies can be approximately equal to the width of the lower body of the box body 3.

[0047] Specifically, the wafer holder 33 cooperates with the slide rail 37 to move the vertically positioned wafer 2 to the left or right side. Spray mechanisms 36 are provided at the corresponding positions on the left and right sides to spray liquid onto the wafer 2 on the wafer holder 33. In other words, the housing 3 is kept moist by the liquid inside. When the flipping base 12 of the wafer transfer device rises, falls, or flips within the housing 3, it remains relatively moist, preventing the polishing fluid on the wafer to be cleaned from drying and condensing, thus providing good protection for the wafer.

[0048] A wafer transfer detection method, implemented by the aforementioned wafer transfer device and wafer holder 33, includes the following steps: The flipped base plate 12 and back plate 11 form an angle, specifically, the flipped base plate 12 and back plate 11 are perpendicular; at this time, the right end of the moving gripper 15 can be located at point B. The movable gripper 15, located on the flip base plate 12, and the support structure 14 cooperate to horizontally clamp the wafer 2. At this time, the movable gripper 15 has a first extension stroke; the first extension stroke of the movable gripper 15 here refers to the right end of the movable gripper 15 being in a position where... Figure 5 Point C in the middle; The first extension stroke is compared with a preset value to determine whether the moving gripper 15 is correctly gripping the wafer 2. In this step, if the first extension stroke is equal to the preset value or the difference is less than the first threshold, it is determined that the moving gripper 15 is correctly gripping the wafer 2. At this time, if the moving gripper 15 is not correctly gripping the wafer 2, a warning signal is issued and subsequent steps are stopped. The preset value is obtained through experiments. Specifically, such as Figure 5 As shown, line segment AB represents the travel distance of the right end of claw 151. Point A is the furthest extension, point B is the initial zero point, and point C is the position of the right end (piston) when claw 151 extends to clamp wafer 2. Point C is a point recorded after experimental determination. If the right end (piston) stops exactly at point C after claw 151 extends, it indicates that a wafer has been detected and the wafer is accurately positioned horizontally. If the right end (piston) is not at point C when the clamping command is issued, it indicates that there is no wafer (the right end may go directly to point A), or the wafer is incorrectly positioned (the right end may be between C and D), or the wafer is not horizontal (the wafer may be tilted, and the right end may be between A and C). This ensures that the wafer clamping in the first step is correct.

[0049] After the moving gripper 15 correctly grips the wafer 2, the flip base plate 12 flips to a vertical state. This means that the flip base plate 12 is vertical relative to the ground, not that the flip base plate 12 and the back plate 11 are vertical. The support structure 14 vertically supports the wafer 2. At this time, the moving gripper 15 changes from state one of gripping the wafer 2 to state two of limiting the wafer 2. Specifically, state two here means that neither of the air vents on both sides of the claw 151 is inhaled, that is, the claw 151 is in a state of no force. At this time, the claw 151 will not put pressure on the wafer 2, so that when the wafer 2 continues to move downward, it can push back the claw 151 and the wafer sits on the wafer support 33 by its own weight. The backplate 11 moves down by X strokes, and the wafer 2 moves down into the wafer holder 33 and abuts against the movable jaw 15 to push the movable jaw 15 to have a second extension stroke; at this time, if the movable jaw 15 has a first extension stroke, it is determined that the wafer 2 is not placed vertically in the wafer holder 33. Assume that the backplate 11, carrying the wafer 2, moves to position D (point D was determined through experiments) when it just touches the wafer holder 33, and has moved X strokes. Assume that after the wafer 2 moves to point D, it still needs to move Y strokes. At this time, the wafer 2 must push back against the claw 151 and move Y strokes back to point E before it can be detached from the wafer holder 33.

[0050] The X travel is compared with the target value to determine whether wafer 2 is placed vertically in wafer holder 33; in this step, if the X travel is equal to the target value or the difference is less than the second threshold, it is determined that wafer 2 is placed vertically in wafer holder 33. If wafer 2 is placed correctly, and the backplate 11 has moved X+Y, with the right end of the claw 151 (piston) just reaching point E, then it can be determined that wafer 2 has been correctly placed on the wafer holder 33. All other cases indicate that wafer 2 is placed incorrectly.

[0051] If the backplate 11 moves X stroke and continues to move downwards, and the right end of the claw 151 (piston) is still at point C and has not yet started to be pushed back by the wafer 2, it also indicates that the wafer 2 is placed incorrectly.

[0052] After wafer 2 is placed vertically in wafer holder 33, the flip base plate 12 rotates relative to the back plate 11, causing the wafer holder 33 to move away from wafer 2 and detach from it. The rotation angle of the flip base plate 12 relative to the back plate 11 can be 2-10°. At this time, the moving gripper 15 returns to its initial zero point, and the flip base plate 12 rotates again relative to the back plate 11. At this time, the cylinder is energized, and the right end (piston) of the gripper 151 retracts to point B.

[0053] The above specific embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A wafer transfer detection method, characterized in that, Includes the following steps: The bottom and back plates are flipped to form an angle. The movable gripper and support structure on the flip base plate cooperate to horizontally clamp the wafer, at which time the movable gripper has a first extension stroke; The first extension stroke is compared with a preset value to determine whether the moving gripper is correctly gripping the wafer; After the moving grippers correctly clamp the wafer, the flip plate flips to a vertical position, and the support structure vertically supports the wafer. The backplate moves down X stroke, and after the wafer falls into the wafer holder, it abuts against the moving jaws to push the moving jaws to have a second extension stroke; The X-stroke is compared with the target value to determine whether the wafer is placed vertically on the wafer holder.

2. The wafer transfer detection method according to claim 1, characterized in that: The process also includes the following steps: after the wafer is placed vertically on the wafer holder, the base plate is flipped and rotated relative to the back plate to detach the wafer.

3. The wafer transfer detection method according to claim 1, characterized in that: After the moving gripper correctly clamps the wafer, the flip plate flips to a vertical state, and the support structure vertically supports the wafer. In this step, the moving gripper changes from state one of clamping the wafer to state two of limiting the wafer.

4. The wafer transfer detection method according to claim 1, characterized in that: During the X-stroke downward movement of the backplate, after the wafer falls into the wafer holder, it abuts against the movable gripper to push the movable gripper to the second extension stroke. If the movable gripper has a first extension stroke, it is determined that the wafer is not placed vertically on the wafer holder.

5. The wafer transfer detection method according to claim 2, characterized in that: After the wafer is placed vertically in the wafer holder, the base plate is rotated relative to the back plate to detach the wafer. In this step, the moving gripper is reset to its initial zero point, and the base plate is rotated relative to the back plate again.

6. The wafer transfer detection method according to claim 1, characterized in that: In the step of comparing the first extension stroke with a preset value to determine whether the moving gripper is correctly gripping the wafer, if the moving gripper is not correctly gripping the wafer, a warning signal is issued and subsequent steps are stopped.

7. The wafer transfer detection method according to claim 1, characterized in that: The movable gripper includes a gripper portion, an air chamber into which one end of the gripper portion extends, and at least two air ports, which are located on both sides of the gripper portion. When the movable gripper has a first extension stroke, air enters through the air port on the first side of the gripper portion. When the movable gripper is converted to the second state of limiting the wafer, air does not enter through the air ports on both sides of the gripper portion.

8. The wafer transfer detection method according to claim 7, characterized in that: When the moving gripper has a second extension stroke, air does not enter through the air ports on both sides of the gripper.

9. The wafer transfer detection method according to claim 7, characterized in that: As the moving gripper retracts to its initial zero point, air enters through the second side air inlet of the gripper.

10. The wafer transfer detection method according to claim 2, characterized in that: The rotation angle of the flip-top plate relative to the back plate is 2-10°.

11. The wafer transfer detection method according to claim 1, characterized in that: In the step of comparing the first extension stroke with a preset value to determine whether the moving gripper is correctly gripping the wafer, if the first extension stroke is equal to the preset value or the difference is less than the first threshold, then it is determined that the moving gripper is correctly gripping the wafer. In the step of comparing the X-stroke with the target value to determine whether the wafer is placed vertically in the wafer holder, if the X-stroke is equal to the target value or the difference is less than the second threshold, then it is determined that the wafer is placed vertically in the wafer holder.

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