Wafer anti-offset centering device

Abstract

This invention provides a wafer anti-displacement centering device, comprising: a support unit, a calibration unit, a centering code reading unit, and a fixed base. The support unit and the calibration unit are independently mounted on the fixed base, and can be independently raised and lowered relative to the fixed base, and are used to switchably support the wafer respectively; the calibration unit can also move horizontally relative to the support unit; the calibration unit is in an initial position before horizontal movement. The centering code reading unit is rotatably fixed on the fixed base, and can rotate around a predetermined axis to capture the wafer's edge information; the wafer is placed on the support unit before the calibration unit moves, and the calibration unit moves horizontally from the initial position toward the wafer to a final position according to the wafer's edge information; the calibration unit can also pick up the wafer at the final position and drive the wafer back to the initial position. This device can keep the wafer stationary during wafer centering and center calibration operations, preventing the wafer from slipping or falling.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor processing technology, and in particular to a wafer anti-displacement centering device. Background Technology

[0002] The main structure of existing wafer alignment devices includes a fixed base and a rotatable and translational wafer carrier unit. The device uses an optical lens or image sensor (such as a CCD sensor) to perform wafer alignment and ID code reading operations.

[0003] When performing wafer centering, center alignment, and angle verification, the wafer is first placed on the wafer carrier unit via a mechanical component. The wafer carrier unit supports the wafer using vacuum chucks or friction posts. A fixed wafer centering unit and an ID reading unit are mounted on the fixed base. After the wafer is placed on the wafer carrier unit, the unit rotates the wafer. The wafer centering unit uses optical or CCD sensors to detect the position of the wafer edge and calculate the degree of eccentricity relative to the rotation axis. Simultaneously, when the wafer centering unit detects a Notch port, the wafer carrier unit rotates the wafer to the corresponding angle so that the ID reading unit can read the code.

[0004] However, after the wafer is placed on the wafer carrier unit, the wafer carrier unit needs to rotate the wafer if it cannot ensure that the center of the wafer coincides with the rotation axis of the wafer carrier unit. Because the wafer has an initial eccentricity relative to the wafer carrier unit, relative sliding can easily occur between the wafer carrier unit and the wafer carrier unit during the rotation process. The accuracy of subsequent center calibration will be adversely affected by the relative sliding, and there is a risk that the wafer may fall or break. Utility Model Content

[0005] To address the problems existing in the prior art, this utility model provides a wafer anti-displacement centering device, which can keep the wafer stationary during wafer centering and center calibration operations, preventing the wafer from sliding or falling.

[0006] To achieve the above objectives, this utility model provides a wafer anti-misalignment center-finding device, comprising: a support unit, a calibration unit, a center-finding code reading unit, and a fixed base. The support unit and the calibration unit are independently disposed on the fixed base. The support unit and the calibration unit can be independently raised and lowered relative to the fixed base and are used to switchably support wafers respectively. The calibration unit can also be horizontally moved relative to the support unit. The calibration unit is in an initial position before horizontal movement.

[0007] The center-finding and code-reading unit is rotatably fixed on the fixed base. The center-finding and code-reading unit can rotate around a predetermined axis and is used to capture the edge information of the wafer. The predetermined axis is the position of the axis of the calibration unit at the initial position.

[0008] The wafer is placed on the carrier unit before the calibration unit moves. The calibration unit is used to move horizontally from the initial position toward the wafer to the endpoint position according to the wafer edge information, pick up the wafer at the endpoint position, and drive the wafer back to the initial position. The endpoint position is the position directly below the center of the wafer when it is placed on the carrier unit.

[0009] Optionally, during the process of the center-finding code reading unit capturing the crystal edge information, the calibration unit moves horizontally from the initial position toward the wafer in real time.

[0010] Optionally, the center-finding code reading unit rotates at least once around the predetermined axis; after the center-finding code reading unit rotates once, the calibration unit moves to the endpoint position.

[0011] Optionally, the code reading and center finding device detects the edge information of the wafer through an optical or image sensor and calculates the degree of eccentricity of the wafer's center relative to the predetermined axis of rotation. The calibration unit can obtain the degree of eccentricity and move horizontally to the endpoint position according to the degree of eccentricity.

[0012] Optionally, the carrier unit includes a vacuum suction cup or multiple friction pads, and / or the calibration unit includes a vacuum suction cup or multiple friction pads.

[0013] Optionally, the carrier unit is sleeved outside the calibration unit, and the calibration unit is capable of rising or falling relative to the carrier unit and picking up the wafer from the carrier unit.

[0014] Optionally, the axis of the bearing unit coincides with the predetermined rotating shaft.

[0015] Optionally, the wafer anti-displacement centering device further includes a robotic arm for carrying and moving the wafer; after the calibration unit returns to the initial position, the robotic arm is inserted between the wafer and the fixed base to pick up the wafer.

[0016] Optionally, when the robotic arm picks up the wafer, the axis of the robotic arm coincides with the predetermined rotating axis.

[0017] Optionally, the center-finding code reading unit also reads the notch on the edge of the wafer during the rotation process; after the calibration unit returns to the initial position, the calibration unit rotates the wafer to a predetermined angle according to the position of the notch.

[0018] This application provides a wafer anti-offset centering device, which can keep the wafer stationary during wafer centering and center calibration operations. The wafer will not rotate during the centering process, avoiding the risk of slippage or falling caused by the initial placement eccentricity of the wafer in traditional solutions, and improving the safety of the wafer centering process.

[0019] Meanwhile, after the centering is completed, the wafer has been accurately picked up by the calibration unit located at the endpoint. The stability of the wafer is then ensured during the translation and rotation driven by the calibration unit, avoiding the risk of slippage and chipping caused by the wafer rotating in an eccentric state, and greatly improving the calibration accuracy. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a wafer centering device in the prior art;

[0021] Figure 2 This is a schematic diagram of the wafer anti-displacement centering device in a preferred embodiment of the present invention.

[0022] In the picture:

[0023] Mechanical section 100; Wafer carrier unit 200; Silicon wafer 300; Wafer centering unit 400;

[0024] 10 wafers; 1 carrier unit; 2 calibration unit; 3 center-finding and code-reading unit; 4 fixed base; 5 predetermined rotating shaft; 6 robotic arm. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0026] The terms “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the mechanism or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0027] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "fixation," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; they can refer to a direct connection or a connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] Reference Figure 1 As shown, in the prior art, the working process of the wafer centering device is as follows: 1) The silicon wafer 300 is placed on the wafer carrier unit 200 by the mechanical unit 100. The wafer carrier unit 200 supports the silicon wafer 300 by means of friction pads or vacuum chucks. 2) The wafer carrier unit 200 drives the silicon wafer 300 to rotate. The wafer centering unit 400 obtains the edge information of the silicon wafer 300 and finds the Notch port. The wafer carrier unit 200 rotates the Notch port to a position below the wafer centering unit 400 to complete the code reading. 3) The wafer carrier unit 200 calibrates the center of the silicon wafer 300 by translation and rotates the silicon wafer 300 to ensure the correct angle when the mechanical unit 100 picks up the wafer.

[0029] Once the wafer eccentricity calculation is complete, the center of the silicon wafer 300 can be calibrated using one of the following two methods: Method 1) The wafer carrier unit 200 is translated within the plane to eliminate the positional deviation between the silicon wafer 300 and the mechanical unit 100 during subsequent wafer pickup, ensuring the correct relative position of the silicon wafer 300 and the mechanical unit 100. Then, the silicon wafer 300 is rotated to ensure the Notch angle required for subsequent processes. Method 2) The wafer carrier unit 200 is first rotated to ensure the Notch angle required for subsequent processes of the silicon wafer 300, and then the wafer pickup action position of the mechanical unit 100 is adjusted to eliminate the positional deviation between the silicon wafer 300 and the mechanical unit 100 during subsequent wafer pickup.

[0030] Both schemes can achieve ID reading, Notch alignment, and centering and center calibration of silicon wafer 300. However, due to the initial position deviation of silicon wafer 300 in the transfer box (FOUP), there is a situation where the center of silicon wafer 300 does not coincide with the axis of wafer carrier unit 200. When silicon wafer 300 rotates, it is easy to slip, or even fall off and break, which not only affects the calibration accuracy of silicon wafer 300, but also endangers product safety.

[0031] The present invention will now be described in detail with reference to the accompanying drawings and preferred embodiments. Unless otherwise specified, the following embodiments and features can complement or combine with each other.

[0032] Reference Figure 2 As shown, a preferred embodiment of this utility model provides a wafer anti-misalignment centering device, including: a support unit 1, a calibration unit 2, a centering code reading unit 3, and a fixed base 4. The support unit 1 and the calibration unit 2 are independently mounted on the fixed base 4, and the support unit 1 and the calibration unit 2 can be independently raised and lowered relative to the fixed base 4. The support unit 1 and the calibration unit 2 are used to switchably support the wafer 10 respectively. The calibration unit 2 can also move horizontally relative to the support unit 1, and the calibration unit 2 is in its initial position before moving horizontally.

[0033] Furthermore, the center-finding and code-reading unit 3 is rotatably fixed on the fixed base 4. The center-finding and code-reading unit 3 can rotate around a predetermined axis 5 and is used to capture the edge information of the wafer 10. The predetermined axis 5 is the position of the axis of the calibration unit 2 at the initial position.

[0034] Reference Figure 2 As shown, wafer 10 is placed on carrier unit 1 before calibration unit 2 moves. Calibration unit 2 is used to move horizontally from initial position to end position in the direction of wafer 10 according to the edge information of wafer 10. End position is the position directly below the center of wafer 10 when wafer 10 is initially placed on carrier unit 1.

[0035] Specifically, when the calibration unit 2 moves, both the wafer 10 and the carrier unit 1 can remain stationary. The calibration unit 2 can move to directly below the wafer 10 based on the edge information detected by the center-finding code reading unit 3, that is, reach the endpoint position.

[0036] In addition, the calibration unit 2 can pick up the wafer 10 at the endpoint and drive the wafer 10 back to the initial position.

[0037] This application provides a wafer anti-offset centering device, which can keep the wafer 10 stationary during the centering and center calibration operations. The wafer will not rotate during the centering process, avoiding the risk of slippage or falling caused by the initial placement eccentricity of the wafer 10 in the traditional solution, and improving the safety of the wafer 10 centering process.

[0038] Meanwhile, after the centering is completed, since the wafer has been accurately picked up by the calibration unit 2 located at the endpoint, the motion stability of the wafer 10 is guaranteed during the translation and rotation driven by the calibration unit 2. This avoids the risk of slippage and chipping caused by the wafer 10 rotating in an eccentric state, and greatly improves the calibration accuracy.

[0039] In an optional embodiment, the carrier unit 1 includes a vacuum chuck or multiple friction pads, in which case the carrier unit 1 can carry the wafer 10 via the vacuum chuck or multiple friction pads. Similarly, the calibration unit 2 may also include a vacuum chuck or multiple friction pads, that is, the calibration unit 2 can also carry the wafer 10 via the vacuum chuck or multiple friction pads.

[0040] In existing technologies, wafer centering and center calibration are sequential operations. Wafer centering can only be performed after wafer centering is completed, resulting in low operating efficiency.

[0041] In a preferred embodiment, during the process of the center-finding and code-reading unit 3 capturing the edge information, the calibration unit 2 moves horizontally from the initial position toward the wafer 10 in real time. That is, the calibration unit 2 can move gradually as the center-finding and code-reading unit 3 rotates, so that the calibration unit 2 reaches the center position of the wafer 10 at the same time as or near the completion of the operation of the center-finding and code-reading unit 3.

[0042] With this configuration, the serial operation that requires waiting for the center to be found before the center can be calibrated in the traditional technical solution is decoupled by the rotatable code reading and center finding unit 3 and the translational calibration unit 2. This allows the center finding and calibration actions of the code reading and center finding unit 3 to partially overlap. At this time, the wafer center finding and center calibration operations are designed to run in parallel, which can shorten the transmission time of wafer 10 and improve production efficiency.

[0043] More specifically, the core-finding unit 3 detects the edge information of the wafer 10 using an optical or image sensor (e.g., a CCD sensor) and calculates the degree of eccentricity of the wafer 10's center relative to the predetermined rotation axis 5. The calibration unit 2 acquires the degree of eccentricity of the wafer 10 and moves horizontally to the endpoint position based on this degree of eccentricity. With this configuration, after the calibration unit 2 picks up and carries the wafer 10 at the endpoint position, since the central axis of the wafer 10 coincides with the central axis of the calibration unit 2, the rotation of the wafer 10 by the calibration unit 2 will not cause slippage or drop, thus improving the safety of the wafer 10 during movement and rotation.

[0044] Furthermore, the center-finding code reading unit 3 rotates at least one revolution around the predetermined axis 5. After the center-finding code reading unit 3 has rotated one revolution, the calibration unit 2 moves to the endpoint position.

[0045] Specifically, since the calibration unit 2 moves during the rotation of the center-finding and code-reading unit 3, the calibration unit 2 will move synchronously or successively to the endpoint position after the center-finding and code-reading unit 3 has rotated once, so as to improve work efficiency.

[0046] Continue to refer to Figure 2 The support unit 1 is mounted on the outside of the calibration unit 2. The calibration unit 2 can rise or fall relative to the support unit 1 and can pick up the wafer 10 from the support unit 1 to place the wafer on the support unit 1 onto the calibration unit 2. At the same time, the support unit 1 can also rise or fall relative to the calibration unit 2. That is to say, the support unit 1 and the calibration unit 2 can move relatively independently in the vertical direction.

[0047] More preferably, the axis of the bearing unit 1 coincides with the predetermined rotating shaft 5, that is, the axis of the bearing unit 1 coincides with the axis of the calibration unit 2 at the initial position. In this way, since the initial position of the calibration unit 2 before horizontal movement coincides with the axis of the bearing unit 1, the moving distance of the calibration unit 2 from the initial position to the end position can be reduced.

[0048] Continue to refer to Figure 2 The wafer anti-displacement centering device also includes a robotic arm 6, which is used to carry and move the wafer 10. Before the wafer 10 is subjected to centering operation, the robotic arm 6 is used to place the wafer 10 on the support unit 1 and then retract it after placement. After the calibration unit 2 returns to its initial position, the robotic arm 6 is used to insert between the wafer 10 and the fixed base 4 and pick up the wafer 10.

[0049] Furthermore, when the robotic arm 6 picks up the wafer 10, the axis of the robotic arm 6 coincides with the predetermined rotating axis 5. At this time, the axis of the robotic arm 6, the axis of the bearing unit 1, and the axis of the calibration unit 2 all coincide, which can ensure that the wafer 10 can be stably placed on the bearing unit 1 without offset or with a small offset.

[0050] In addition, the core-finding code reading unit 3 also reads the notch (not shown) on the edge of the wafer 10 during the rotation process, while the wafer 10 remains stationary throughout the code reading process. After the calibration unit 2 returns the wafer 10 to its initial position, the calibration unit 2 rotates the wafer 10 to a predetermined angle according to the position of the notch.

[0051] With this setup, during the center calibration process of wafer 10, once calibration unit 2 has moved to the center position of wafer 10 (i.e., the endpoint position), after calibration unit 2 acquires wafer 10, it only needs to be translated to the position where robot arm 6 acquires wafer 10 (i.e., the initial position) and rotated to the required process angle. This avoids the wafer 10 shifting and falling due to eccentricity during the movement of robot arm 6, ensuring the accuracy of wafer 10's placement and removal in the transfer box and process equipment.

[0052] Furthermore, after the calibration unit 2 rotates the wafer 10, the robot arm 6 moves to the position to pick up the wafer 10. The calibration unit 2 then lowers the wafer 10 until it is placed on the robot arm 6. Since the axis of the calibration unit 2 coincides with the axis of the robot arm 6, the wafer 10 and the robot arm 6 are now coaxial, allowing the robot arm 6 to smoothly move the wafer 10 to the next processing position.

[0053] In a non-limiting embodiment, the operation of the wafer anti-misalignment centering device is as follows:

[0054] 1)Reference Figure 2 As shown, the wafer 10 is first placed on the support unit 2 by the robot arm 6. The support unit 2 can support the wafer 10 by means of friction pads or vacuum suction cups.

[0055] 2) The center-finding code reading unit 3 scans and obtains the edge information of the wafer 10 by rotating around the predetermined axis 5, thereby obtaining the center position of the wafer 10 and finding the notch (i.e., the notch) on the edge of the wafer 10. The center-finding code reading unit 3 can complete the code reading when it rotates to the notch position.

[0056] 3) During the process of the center-finding and code-reading unit 3 searching for the center of wafer 10, the calibration unit 2 can move from its initial position to approach the endpoint position directly below the center of wafer 10 by translation. When the code-finding and code-reading unit 3 stops working, the calibration unit 2 is already at the endpoint position.

[0057] 4) The calibration unit 2 picks up the wafer 10 located on the carrier unit 2 at the end position by lifting and lowering.

[0058] 5) The calibration unit 2 translates the wafer 10 to the position (i.e., initial position) of the wafer 10 obtained by the robot arm 6. The calibration unit 2 rotates the wafer 10 to a predetermined angle to calibrate the Notch angle required for the next process of the wafer 10 by rotation.

[0059] 6) The calibration unit 2 places the wafer 10 onto the robot arm 6 by lifting and lowering, and then the robot arm 6 can move the wafer 10 to the next process position.

[0060] In summary, this utility model provides a wafer anti-offset centering device that can keep the wafer 10 stationary during the centering and center calibration operations. The wafer will not rotate during the centering process, avoiding the risk of slippage or falling caused by the initial placement eccentricity of the wafer 10 in the traditional solution, and improving the safety of the wafer 10 centering process.

[0061] Meanwhile, after the centering is completed, since the wafer 10 has been accurately picked up by the calibration unit 2 located at the endpoint, the motion stability of the wafer 10 is guaranteed during the translation and rotation driven by the calibration unit 2. This avoids the risk of slippage and chipping caused by the wafer 10 rotating in an eccentric state in the traditional solution, and greatly improves the calibration accuracy.

[0062] The above description is only a description of the preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the present utility model.

Claims

1. A wafer anti-misalignment centering device, characterized in that, include: The system includes a carrier unit, a calibration unit, a core-finding and code-reading unit, and a fixed base. The carrier unit and the calibration unit are independently mounted on the fixed base. The carrier unit and the calibration unit can be independently raised and lowered relative to the fixed base and are used to switchably carry wafers respectively. The calibration unit can also move horizontally relative to the carrier unit. The calibration unit is in its initial position before moving horizontally. The center-finding and code-reading unit is rotatably fixed on the fixed base. The center-finding and code-reading unit can rotate around a predetermined axis and is used to capture the edge information of the wafer. The predetermined axis is the position of the axis of the calibration unit at the initial position. The wafer is placed on the carrier unit before the calibration unit moves. The calibration unit is used to move horizontally from the initial position toward the wafer to the endpoint position according to the wafer edge information, pick up the wafer at the endpoint position, and drive the wafer back to the initial position. The endpoint position is the position directly below the center of the wafer when it is placed on the carrier unit.

2. The wafer anti-misalignment centering device as described in claim 1, characterized in that, During the process of the center-finding code reading unit capturing the crystal edge information, the calibration unit moves horizontally from the initial position toward the wafer in real time.

3. The wafer anti-misalignment centering device as described in claim 2, characterized in that, The center-finding code reading unit rotates at least once around the predetermined axis; after the center-finding code reading unit rotates once, the calibration unit moves to the endpoint position.

4. The wafer anti-misalignment centering device as described in any one of claims 1 to 3, characterized in that, The center-finding and code-reading unit detects the edge information of the wafer using an optical or image sensor and calculates the degree of eccentricity of the wafer's center relative to the predetermined axis of rotation. The calibration unit acquires the degree of eccentricity and moves horizontally to the endpoint position according to the degree of eccentricity.

5. The wafer anti-misalignment centering device as described in any one of claims 1 to 3, characterized in that, The carrier unit is sleeved outside the calibration unit, and the calibration unit can rise or fall relative to the carrier unit and pick up the wafer from the carrier unit.

6. The wafer anti-misalignment centering device as described in claim 5, characterized in that, The axis of the bearing unit coincides with the predetermined rotating shaft.

7. The wafer anti-misalignment centering device as described in any one of claims 1 to 3, characterized in that, It also includes a robotic arm for carrying and moving the wafer; after the calibration unit returns to the initial position, the robotic arm is used to insert between the wafer and the fixed base and pick up the wafer.

8. The wafer anti-misalignment centering device as described in claim 7, characterized in that, When the robotic arm picks up the wafer, the axis of the robotic arm coincides with the predetermined rotating axis.

9. The wafer anti-misalignment centering device as described in any one of claims 1 to 3, characterized in that, The bearing unit includes a vacuum suction cup or multiple friction pads, and / or the calibration unit includes a vacuum suction cup or multiple friction pads.

10. The wafer anti-misalignment centering device according to any one of claims 1 to 3, characterized in that, The center-finding and code-reading unit also reads the notch on the edge of the wafer during the rotation process; after the calibration unit returns to the initial position, the calibration unit rotates the wafer to a predetermined angle according to the position of the notch.

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