Method, device and medium for detecting carrier positions for loading wafers

Abstract

Embodiments of the present application disclose a carrier position detection method and device for loading wafers, and a medium; the detection method comprises: placing a target carrier at a corresponding target position in a lower tray by a mechanical hand, and collecting an image of the target carrier by a CCD camera as a target image; placing a plurality of to-be-detected carriers on the lower tray before double-sided polishing starts, and collecting actual images corresponding to each to-be-detected carrier; comparing the actual images corresponding to each to-be-detected carrier with the target image respectively, and determining whether each to-be-detected carrier is located at the target position.

Description

Technical Field

[0001] The present invention relates to the field of wafer processing technology, and in particular to a method, apparatus and medium for detecting the position of a carrier for loading wafers. Background Technology

[0002] In wafer manufacturing, wafers are typically placed in sealed, clean containers or cassettes, and robotic arms automatically handle the loading and unloading operations between these containers / cassettes and the process chamber to prevent contamination by foreign particles. For example, in a double-sided polishing process, multiple carriers are usually installed within the process chamber of the double-sided processing equipment. Each carrier has one or more holding holes for placing wafers. The carriers are connected to a motor controller that drives them to rotate at a specific angle. During the loading and unloading operation, the carrier first rotates at a certain angle under the control of the motor controller, positioning one of the holding holes at a designated loading / unloading position. The robotic arm then moves to directly above this holding hole to perform the loading or unloading operation.

[0003] Understandably, before the double-sided polishing operation begins, the carrier needs to be placed on the lower platen. Then, a robotic arm horizontally places the wafer into the holding hole of the carrier body, so that the carrier can move the wafer to polish the upper and lower surfaces. The movement of the carrier is driven by the meshing of the teeth on the outer peripheral gear with the teeth of the central gear on the lower platen. During the polishing process, multiple carriers are placed on the lower platen simultaneously. These carriers revolve together around the center of the lower platen while also rotating on their own centers, ensuring that each wafer carried by each carrier is polished over a larger area of ​​the lower platen, thereby improving polishing uniformity.

[0004] Based on current production experience, a better polishing effect is achieved only when the initial position of the wafer on the lower mounting plate is within the target position before the double-sided polishing operation begins. Therefore, it is necessary to position the carrier and wafer according to the target position. Currently, the method for detecting the carrier position involves using a laser to mark the target position of one tooth of each carrier on the lower mounting plate. Then, the operator visually observes whether the tooth is close to the laser mark when placing the carrier. If it is approximately close, the carrier is considered to be in the target position. However, errors in visual observation can lead to a significant difference between the actual position of the carrier and the target position, thus affecting the double-sided polishing effect of the wafer. Summary of the Invention

[0005] In view of this, the present invention aims to provide a method, apparatus and medium for detecting the position of a carrier used for loading wafers; it can quickly detect whether there is a positional deviation of each carrier under test when it is installed on the lower platen, avoid the situation of unsatisfactory wafer polishing effect caused by the positional deviation of the carrier under test, and improve the wafer process yield.

[0006] The technical solution of this invention is implemented as follows:

[0007] In a first aspect, embodiments of the present invention provide a method for detecting the position of a carrier used for loading wafers, the detection method comprising:

[0008] The target vehicle is placed at the corresponding target position in the lower plate by a robotic arm, and the image of the target vehicle is acquired by a charge-coupled device (CCD) camera as the target image.

[0009] Before double-sided polishing begins, multiple test vehicles are placed on the lower plate, and actual images of each test vehicle are captured.

[0010] The actual image corresponding to each of the vehicles under test is compared with the target image to determine whether each vehicle under test is located at the target location.

[0011] Secondly, embodiments of the present invention provide a device for detecting the position of a carrier used for loading wafers, the detection device comprising:

[0012] robotic arm, CCD camera and controller; among which,

[0013] The robotic arm is used to place the target carrier at the corresponding target position in the lower platen; and to place multiple test carriers on the lower platen before the double-sided polishing begins.

[0014] The CCD camera is used to capture images of the target vehicle as target images; and to acquire actual images corresponding to each of the vehicles under test.

[0015] The controller is configured to compare the actual image corresponding to each of the vehicles under test with the target image to determine whether each vehicle under test is located at the target location.

[0016] Thirdly, embodiments of the present invention provide a computer storage medium storing a detection program for the position of a carrier for loading wafers. When the detection program for the position of a carrier for loading wafers is executed by at least one processor, it implements the steps of the method for detecting the position of a carrier for loading wafers described in the first aspect.

[0017] This invention provides a method, apparatus, and medium for detecting the position of a wafer carrier. First, a target image of the target carrier at its target position on the lower mounting plate is acquired. Then, before double-sided polishing begins, each carrier to be tested is sequentially installed on the lower mounting plate, and an actual image corresponding to each carrier is acquired. Finally, the actual images corresponding to each carrier to be tested are compared with the acquired target image to determine whether each carrier to be tested is at its target position on the lower mounting plate. Figure 3 The method shown can quickly detect whether there is a positional deviation when each test carrier is installed on the lower platen, avoiding unsatisfactory wafer polishing results caused by the positional deviation of the test carrier, and improving the wafer process yield. Attached Figure Description

[0018] Figure 1 This is a side view of the structure of the double-sided polishing equipment provided in an embodiment of the present invention;

[0019] Figure 2 This is a top view of a double-sided polishing device provided in an embodiment of the present invention;

[0020] Figure 3 A schematic flowchart of a method for detecting the position of a carrier used for loading wafers, provided in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram showing the installation position of the CCD camera according to an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the target position of the target vehicle in the lower platen provided in an embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the actual position of the vehicle under test provided in an embodiment of the present invention;

[0024] Figure 7 This is a schematic diagram showing the skew direction of the actual position of the vehicle under test relative to the target position, provided in an embodiment of the present invention.

[0025] Figure 8 This is a schematic diagram of the composition of a wafer loading carrier position detection device provided in an embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0027] See Figure 1 The diagram shows a general side view of the structure of a double-sided polishing device 1 that applies the technical solution of an embodiment of the present invention. Figure 2 for Figure 1The top view of the double-sided polishing equipment 1 shown should be noted that... Figure 1 It is along Figure 2 A cross-sectional view of the RR′ line. Combined with... Figure 1 and Figure 2 The double-sided polishing device 1 includes:

[0028] The upper fixed plate 10 and the lower fixed plate 20 are set opposite to each other in the upward and downward directions;

[0029] Polishing pad 30, wherein the polishing pad 30 is respectively disposed below the upper fixed plate 10 and above the lower fixed plate 20;

[0030] A central gear 40 is installed at the center between the upper fixed plate 10 and the lower fixed plate 20;

[0031] An internal gear 50 is installed at the periphery between the upper fixed plate 10 and the lower fixed plate 20;

[0032] A tray formed by multiple carriers 60 is disposed around the central gear 40. Each carrier 60 includes a body 601 with a circular opening and a ring of rubber 602 arranged around the opening. Understandably, the ring of rubber 602 around the opening of the carrier 60 forms a retaining hole 603 to hold the wafer W to be polished. Understandably, the wafer W is clamped between the upper fixed plate 10 and the lower fixed plate 20, mounted within the retaining hole 603 of the carrier 60; and since the carrier 60 is typically made of stainless steel, the rubber ring 602 around the opening of the carrier 60 is typically used to avoid unnecessary wear on the wafer W.

[0033] In addition, such as Figure 2 As shown, the outer peripheral teeth 70 of each carrier 60 mesh with the teeth of the central gear 40 and the internal gear 50. The upper fixed plate 10 and the lower fixed plate 20 are driven to rotate by a drive device (not shown in the figure), thereby causing each carrier 60 to rotate on its own axis while revolving around the central gear 40. Simultaneously, the wafer W, mounted in the holding hole 603, is held on the carrier 60, and its front and back sides are polished simultaneously through contact with the polishing pad 30. During the polishing process, polishing fluid is supplied to the polishing pad 30 from a nozzle (not shown in the figure).

[0034] Before performing double-sided polishing on wafer W, a robotic arm is typically used to move multiple carriers 60 and accurately place them at designated positions on the lower tray 20. However, during implementation, due to visual errors, there is a high probability that the placement of the carriers 60 will deviate from the corresponding target position. This can lead to deviations when wafer W is placed in the holding hole 603 of the carrier. In severe cases, the deviation in the position of the carriers 60 may even cause the edge of wafer W to overlap with the periphery of the opening of the carrier body 601, a phenomenon known as "edge overlap." Consequently, the desired polishing effect may not be achieved during double-sided polishing, and wafer W may even be scrapped.

[0035] It should be noted that, in Figure 1 and Figure 2 The example shown only shows one retaining hole 603 on the carrier body 601. In actual production, multiple retaining holes 603 may be provided on the carrier body 601.

[0036] Based on this, the present invention aims to provide a detection scheme for detecting the placement position of the carrier in the lower die, so as to detect whether there is a deviation in the placement of the carrier in the lower die, to ensure the accurate placement of the carrier, improve the double-sided polishing effect of the wafer, and improve the process yield.

[0037] Based on the above explanation, see Figure 3 This invention illustrates a method for detecting the position of a wafer carrier according to an embodiment of the present invention. The detection method includes:

[0038] S301. The target vehicle is placed at the corresponding target position in the lower plate by a robotic arm, and the image of the target vehicle is captured by a CCD camera as the target image.

[0039] S302. Before the double-sided polishing begins, place multiple test vehicles on the lower plate and acquire the actual image corresponding to each test vehicle.

[0040] S303. Compare the actual image corresponding to each of the vehicles under test with the target image to determine whether each vehicle under test is located at the target position.

[0041] for Figure 3 The detection method shown first acquires a target image of the target vehicle at the target position on the lower platen. Then, before double-sided polishing begins, each vehicle to be tested is sequentially installed on the lower platen, and an actual image corresponding to each vehicle is acquired. Finally, the actual images corresponding to each vehicle to be tested are compared with the acquired target images to determine whether each vehicle to be tested is at the target position on the lower platen. Figure 3The method shown can quickly detect whether there is a positional deviation when each test carrier is installed on the lower platen, avoiding unsatisfactory wafer polishing results caused by the positional deviation of the test carrier, and improving the wafer process yield.

[0042] for Figure 3 The detection method shown, in some possible implementations, includes placing multiple test vehicles on the lower plate before double-sided polishing begins, and acquiring an actual image corresponding to each test vehicle, including:

[0043] Before the double-sided polishing begins, each of the test vehicles in the lower plate is rotated to be directly below the CCD camera so that the CCD camera can capture an actual image of each vehicle.

[0044] Specifically, in this embodiment of the invention, in order to ensure that the acquired target image and the actual image are under the same shooting conditions, such as... Figure 4 As shown, in this embodiment of the invention, a CCD camera 41 is fixedly arranged above the lower plate 20. After the CCD camera 41 completes the shooting of the target vehicle directly below to obtain the target image, before the double-sided polishing process begins, each test vehicle 60 is rotated to be directly below the CCD camera 41 to collect the actual image corresponding to each test vehicle 60.

[0045] for Figure 3 The detection method shown, in some possible implementations, includes comparing the actual image corresponding to each of the vehicles under test with the target image to determine whether each vehicle under test is located at the target position, including:

[0046] For each vehicle, the positional relationship between the actual marker pattern in the actual image and the corresponding target marker pattern in the target image is compared.

[0047] If the position of the actual marking pattern coincides with the position of the target actual marking pattern, it is determined that the vehicle under test is located at the target position;

[0048] If the position of the actual marking pattern does not coincide with the position of the target actual marking pattern, it is determined that the vehicle under test is not located at the target position.

[0049] In some examples of the above implementation, the triangular patterns at the center of the target vehicle and the vehicle under test are set as the target marking pattern and the actual marking pattern, respectively.

[0050] It should be noted that, based on production experience, the actual images corresponding to the initial positions of each test vehicle 60 in the current positioning 20 are as follows:Figure 5 As shown, this indicates that the polished wafer W has a good polishing effect, meaning that... Figure 5 The target position corresponding to the target vehicle is shown, which is the target position of each vehicle under test in the lower positioning plate 20. Based on the above target position, in order to determine whether each vehicle under test 60 is at the target position in the lower positioning plate 20, a triangle image at the center of the vehicle can be selected as a marker pattern. The triangle pattern in the actual image is compared with the triangle image in the target image. If the triangle image in the actual image and the triangle image in the target image coincide, it means that the vehicle under test is located at the target position.

[0051] for Figure 3 The detection method shown, in some possible implementations, further includes:

[0052] If the vehicle under test is not located at the target position, obtain the skew direction and offset of the actual position of the vehicle under test relative to the target position;

[0053] A repositioning request is sent to the robotic arm so that the robotic arm executes the repositioning request and moves the test vehicle, which was not accurately placed, back to the target position according to the skew direction and the offset.

[0054] Understandably, such as Figure 6 As shown, when the triangular pattern in the acquired actual image does not coincide with the triangular pattern in the target image, the offset *l* of the actual position of the vehicle under test relative to the target position is first obtained by using the distance between the centers of the actual image (shown by the dashed line in the figure) and the target image (shown by the solid line in the figure); then, as... Figure 7 The angle θ between the triangular pattern in the actual image and the triangular pattern in the target image is obtained as the deflection direction of the test vehicle. Then, the test vehicle is first moved by the above-mentioned offset amount l by the robot arm, and then the test vehicle is rotated clockwise around its center by an angle θ, so that the test vehicle is located at the target position.

[0055] The specific solution for the wafer location detection method described above can be embodied in the form of a software product. This software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the method described in this embodiment. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0056] Therefore, this embodiment provides a computer storage medium storing a program for detecting the position of a carrier for loading wafers. When the program for detecting the position of a carrier for loading wafers is executed by at least one processor, it implements the steps of the method for detecting the position of a carrier for loading wafers described in the above technical solution.

[0057] Based on the same inventive concept as the aforementioned technical solution, see [link to inventive concept]. Figure 8 This illustrates the composition of a wafer loading carrier position detection device 80 provided in an embodiment of the present invention. This detection device 80 can be applied to... Figure 1 The double-sided polishing equipment 1 shown can also be applied to wafer processing equipment with a process chamber and requiring wafer support during processing. Details are not elaborated in this embodiment. The detection device 80 may include: a robotic arm 801, a CCD camera 802, and a controller 803; wherein...

[0058] The robotic arm 801 is used to place the target carrier at the corresponding target position in the lower platen; and to place multiple test carriers on the lower platen before the double-sided polishing begins.

[0059] The CCD camera 802 is used to capture images of the target vehicle as target images; and to acquire actual images corresponding to each of the vehicles under test.

[0060] The controller 803 is configured to compare the actual image corresponding to each of the vehicles under test with the target image to determine whether each vehicle under test is located at the target location.

[0061] In some examples, the controller 803 is configured as follows:

[0062] For each vehicle, the positional relationship between the actual marker pattern in the actual image and the corresponding target marker pattern in the target image is compared.

[0063] If the position of the actual marking pattern coincides with the position of the target actual marking pattern, it is determined that the vehicle under test is located at the target position;

[0064] If the position of the actual marking pattern does not coincide with the position of the target actual marking pattern, it is determined that the vehicle under test is not located at the target position.

[0065] In some examples, the controller 803 is also configured to:

[0066] If the vehicle under test is not located at the target position, obtain the skew direction and offset of the actual position of the vehicle under test relative to the target position;

[0067] A repositioning request is sent to the robotic arm so that the robotic arm executes the repositioning request and moves the test vehicle, which was not accurately placed, back to the target position according to the skew direction and the offset.

[0068] It is understood that the exemplary technical solution of the wafer loading carrier position detection device 80 described above belongs to the same concept as the technical solution of the wafer loading carrier position detection method described above. Therefore, all details not described in detail above regarding the technical solution of the wafer loading carrier position detection device 80 can be found in the description of the technical solution of the wafer loading carrier position detection method described above. This embodiment of the invention will not elaborate further on these details.

[0069] It should be noted that the technical solutions described in the embodiments of the present invention can be combined arbitrarily without conflict.

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for detecting the position of a carrier used for loading wafers, characterized in that, The detection method includes: The target vehicle is placed at the corresponding target position in the lower plate by a robotic arm, and the image of the target vehicle is captured by a CCD camera as the target image. Before double-sided polishing begins, multiple test vehicles are placed on the lower plate, and actual images of each test vehicle are captured. The actual image corresponding to each of the vehicles under test is compared with the target image to determine whether each vehicle under test is located at the target position. If the vehicle under test is not located at the target position, obtain the skew direction and offset of the actual position of the vehicle under test relative to the target position; A repositioning request is sent to the robotic arm so that the robotic arm executes the repositioning request and moves the test vehicle, which was not accurately placed, back to the target position according to the skew direction and the offset. The step of comparing the actual image corresponding to each of the vehicles under test with the target image to determine whether each vehicle under test is located at the target position includes: For each vehicle, the positional relationship between the actual marker pattern in the actual image and the corresponding target marker pattern in the target image is compared. If the position of the actual marking pattern coincides with the position of the target marking pattern, it is determined that the vehicle under test is located at the target position; If the position of the actual marking pattern does not coincide with the position of the target marking pattern, it is determined that the vehicle under test is not located at the target position.

2. The detection method according to claim 1, characterized in that, Before the double-sided polishing begins, multiple test carriages are placed on the lower plate, and actual images of each test carriage are acquired, including: Before the double-sided polishing begins, each of the test vehicles in the lower plate is rotated to be directly below the CCD camera so that the CCD camera can capture an actual image of each vehicle.

3. The detection method according to claim 1, characterized in that, The triangular patterns at the center of the target vehicle and the vehicle under test are respectively designated as the target marking pattern and the actual marking pattern.

4. A device for detecting the position of a carrier used for loading wafers, characterized in that, The detection device includes: a robotic arm, a CCD camera, and a controller; wherein... The robotic arm is used to place the target carrier at the corresponding target position in the lower platen; and to place multiple test carriers on the lower platen before the double-sided polishing begins. The CCD camera is used to capture images of the target vehicle as target images; and to acquire actual images corresponding to each of the vehicles under test. The controller is configured to compare the actual image corresponding to each of the vehicles under test with the target image to determine whether each vehicle under test is located at the target position. The controller is also configured to: If the vehicle under test is not located at the target position, obtain the skew direction and offset of the actual position of the vehicle under test relative to the target position; A repositioning request is sent to the robotic arm so that the robotic arm executes the repositioning request and moves the test vehicle, which was not accurately placed, back to the target position according to the skew direction and the offset. The controller is also configured to: For each vehicle, the positional relationship between the actual marker pattern in the actual image and the corresponding target marker pattern in the target image is compared. If the position of the actual marking pattern coincides with the position of the target marking pattern, it is determined that the vehicle under test is located at the target position; If the position of the actual marking pattern does not coincide with the position of the target marking pattern, it is determined that the vehicle under test is not located at the target position.

5. A computer storage medium, characterized in that, The computer storage medium stores a detection program for the position of a carrier for loading wafers, which, when executed by at least one processor, implements the steps of the method for detecting the position of a carrier for loading wafers according to any one of claims 1 to 3.

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