Cleaning method for wafer edge polishing

Abstract

The invention provides a cleaning method for wafer edge polishing, which comprises the following steps: after each wafer is processed at the current station and taken away, and before the next wafer is put in, local cleaning operation is automatically executed on the station; when the whole batch of wafers are processed and all the stations are idle, performing integral cleaning operation on all the stations automatically; wherein the stations at least comprise one first type of station and at least one second type of station; and the operation methods for local cleaning or overall cleaning of the first type of stations and the second type of stations are different. According to the cleaning method, different cleaning methods are executed for the stations in different machining states, on the basis that the normal production rhythm is not affected, the cleanliness of the suction cup pad and the whole equipment can be effectively cleaned in time, the polishing and cleaning effect is guaranteed, and the scratch occurrence rate is remarkably reduced; and the polishing quality and the production yield of the wafer are further improved.

Description

Technical Field

[0001] This application belongs to the field of silicon wafer polishing technology, and in particular relates to a cleaning method for polishing the edge of a wafer. Background Technology

[0002] Edge polishing is a critical process in wafer manufacturing, used to improve the flatness and smoothness of wafer edges. Traditional edge polishing equipment typically includes multiple stations, such as V-groove processing stations and rotary processing stations, where wafers are processed sequentially. However, in existing technologies, there is no cleaning step before the wafer is placed into the chuck, which can lead to particle contamination on the wafer surface. During processing, these particles gradually accumulate on the chuck pad. Because the chuck pad applies pressure when adsorbing the wafer, the accumulated particles can cause scratches on the wafer surface, known as abrasions. These abrasion defects reduce wafer quality and yield, thus requiring improved methods and equipment to reduce their occurrence. Summary of the Invention

[0003] This application provides a cleaning method for wafer edge polishing to solve the technical problem of how to reduce wafer scratches caused by particle accumulation during edge polishing.

[0004] To solve at least one of the above-mentioned technical problems, the technical solution adopted in this application is:

[0005] A cleaning method for polishing the edge of a wafer, comprising the following steps:

[0006] After each wafer finishes processing at the current workstation and is removed, and before the next wafer is placed in, a local cleaning operation is automatically performed on that workstation.

[0007] When the entire batch of wafers is processed and all workstations are idle, an automatic overall cleaning operation is performed on all workstations.

[0008] The workstation includes at least one first-type workstation and at least one second-type workstation; and the operation methods for partial or overall cleaning of the first-type workstation and the second-type workstation are different.

[0009] Furthermore, both the first type of workstation and the second type of workstation are equipped with a first water supply system; the second type of workstation also includes a second water supply system, and both the second water supply system and the first water supply system spray water onto the upper surface of the suction cup pad.

[0010] Furthermore, the local cleaning operation includes:

[0011] Stop the vacuum valve at the current workstation from drawing air;

[0012] Turn on the first water supply system to allow water to flow through the holes on the suction cup pad and spray out to rinse the upper surface of the suction cup pad.

[0013] Furthermore, during the localized cleaning process, the suction cup pads on the first type of workstation remain fixed in place, and cleaning is stopped after 8-12 seconds.

[0014] Furthermore, during localized cleaning, the suction cup pads on the second type of workstation rotate at a preset speed several times while being cleaned, and stop cleaning after reaching the preset number of rotations; wherein, the suction cup pads on the second type of workstation rotate at a speed of 135-140 r / min and rotate 8-12 times.

[0015] Furthermore, the overall cleaning operation includes:

[0016] For the first type of workstation, lock the loading port and turn on the first water supply system to spray water to clean the fixed suction cup pad;

[0017] For the second type of workstation, the loading port is locked, the first water supply system and the second water supply system are turned on, and the suction cup pad and the upper spray head are simultaneously controlled to rotate while cleaning; wherein, the rotation speed of the suction cup pad is 135-140 r / min, the rotation speed of the upper spray head is 450-550 r / min, and the cleaning ends after 25-30 seconds.

[0018] Furthermore, the first water supply system is located below the suction cup pad, and its spray pipe passes through the center of the suction cup pad and sprays water onto its surface.

[0019] Furthermore, the second water supply system is located above the suction cup pad and has three water spray pipes, two of which are symmetrically arranged and correspond to the two upper throwing heads; the other water spray pipe passes through the center of the rotating carrier used to fix and drive the upper throwing heads to rotate.

[0020] Furthermore, during the overall cleaning process, the rotating carrier is controlled to drive the upper spray head to rotate, and the two rotating upper spray heads are cleaned by the symmetrical water spray pipes at both ends of the second water supply system; the water flow is thrown onto the cover wall surface set outside the upper spray head as the upper spray head rotates; the water spray pipe located in the middle of the second water supply system passes through the center of the rotating carrier, and the water flow is driven by the rotating carrier to disperse and fall onto the upper surface of the suction cup pad to rinse the suction cup pad.

[0021] Furthermore, the first type of station is a V-groove machining station; the second type of station is a rotary machining station.

[0022] The cleaning method for wafer edge polishing designed in this application implements different cleaning methods for workstations after different processing states. It can clean the suction cup pads and the cleanliness of the entire equipment in a timely and effective manner without affecting the normal production rhythm, ensuring the polishing cleaning effect, significantly reducing the incidence of scratches, and thus improving the polishing quality and production yield of wafers.

[0023] This cleaning method performs localized cleaning after each wafer is processed, effectively removing particles from the chuck pads and reducing the risk of scratches caused by particle accumulation. Simultaneously, it performs overall cleaning when the machine is idle, further ensuring equipment cleanliness and achieving efficient cleaning. By automatically performing cleaning operations after each silicon wafer polishing process, particle accumulation on the chuck pads can be effectively removed, significantly reducing the incidence of wafer scratches and improving wafer yield and equipment utilization. Attached Figure Description

[0024] Figure 1 This is a flowchart of a cleaning method for polishing the edge of a wafer according to this application;

[0025] Figure 2 This is a perspective view of the first type of station cleaning in this application;

[0026] Figure 3 This is a perspective view of the second type of workstation cleaning in this application;

[0027] Figure 4 This is a structural diagram of the second water supply system in this application;

[0028] Figure 5 This is a perspective view of the second type of workstation cleaning in this application.

[0029] In the diagram: 10, V-groove suction cup pad; 20, first water supply system; 21, first water spray pipe; 22, first water supply valve; 30, vacuum supply system; 31, vacuum valve; 40, rotating suction cup pad; 50, second water supply system; 51, second water spray pipe; 52, second water supply valve; 53, cover; 54, upper throwing head; 55, rotating carrier. Detailed Implementation

[0030] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0031] This embodiment proposes a cleaning method for polishing the edges of wafers, such as... Figure 1 As shown, the adaptation is as follows Figure 2-5The polishing equipment shown includes the following steps: after each wafer completes processing at its current station and is removed, and before the next wafer is placed in, a local cleaning operation is automatically performed on that station; when the entire batch of wafers is processed and all stations are idle, the loading port is locked and an overall cleaning operation is automatically performed on all stations. The stations include at least one first-type station and at least one second-type station; in this embodiment, the first-type station is a V-groove processing station, and the second-type station is a rotary processing station. Furthermore, the methods for local or overall cleaning of the first-type and second-type stations differ.

[0032] In this embodiment, at least two first-type workstations and three second-type workstations are provided, that is, at least two V-groove processing workstations and three rotary processing workstations are provided. The two V-groove processing workstations are arranged adjacent to each other, and each V-groove processing workstation is provided with a V-groove suction cup pad 10. The suction cup pad only has an adsorption function and does not have a rotation function. Only the first water supply system 20 is used for cleaning. The three rotary processing workstations are arranged adjacent to each other, and each rotary processing workstation is provided with a rotary suction cup pad 40. The rotary suction cup pad 40 is rotated by a rotary disk. The workstation is also provided with a rotatable upper polishing head 54. During cleaning, the first water supply system 20 and the second water supply system 50 can be used.

[0033] According to the processing sequence, the V-groove is first polished at the V-groove processing station, and then the outer diameter is polished at the rotary processing station. Because the V-groove processing station and the rotary processing station have different characteristics, their localized and overall cleaning operations also differ.

[0034] like Figure 2-3 As shown, both the first and second type of workstations are equipped with a first water supply system 20 that supplies water to the suction cup pads from below for cleaning. The first water supply system 20 sprays pure water cleaning solution upward through the center of the suction cup pad via a first spray pipe 21, and the flow rate is controlled by a first water supply valve 22. After being sprayed out, the pure water flows in an arc shape, spreading outward from the center and spraying onto the V-groove suction cup pad 10 and the rotating suction cup pad 40. Each workstation is equipped with a vacuum supply system 30, which controls the suction through a vacuum valve 31, thereby controlling the suction cup pad to hold the wafer.

[0035] like Figure 4-5The second type of workstation also includes a second water supply system 50 located above the wafer. The second water supply system 50 is housed within a housing 53, which contains a set of symmetrically arranged upper polishing heads 54 fixed to a rotating carrier 55. The second water supply system 50 includes three second water spray pipes 51, all arranged along a single diameter. One of the second water spray pipes 51 corresponds directly to the central through-hole of the rotating carrier 55, while the other two second water spray pipes 51 correspond directly to the upper polishing heads 54. During spraying, the second spray pipe 51 is fixed to the cover 53, and its position height depends on the height of the cover 53. The rotating carrier 55 drives the upper throwing head 54 to rotate, and the water flow at the center position flows vertically downward to the rotating suction cup pad 40. The water flow on both sides is thrown onto the inner wall of the cover 53 as the upper throwing head 54 rotates, and the water flow on both sides carries the washed impurities down the inner wall of the cover 53 to the outer side of the rotating suction cup pad 40. The water flow in the center is sprayed downward with the rotating carrier 55, which forms a cross spray with the water flow in the first water supply system 20, thereby covering the upper surface of the suction cup pad and quickly washing away the impurities. In this cleaning process, both the second water supply system 50 and the first water supply system 20 spray onto the upper surface of the suction cup pad, forming a cross spray effect on the rotating suction cup pad 40. Centrifugal force and water flow are used in conjunction to remove particles from the rotating suction cup pad 40.

[0036] The cleaning operations for both Type I and Type II workstations include partial cleaning and overall cleaning, and the detailed operating steps are as follows:

[0037] Local cleaning is triggered when a single wafer is processed and removed from the V-groove processing station, and then a cleaning operation is performed immediately at the same V-groove processing station.

[0038] For the first type of workstation, the local cleaning only involves rinsing the V-groove suction cup pad 10 by the first water supply system 20. Specifically, the vacuum valve 31 at the current workstation is stopped; that is, after the current wafer processing is completed, the vacuum valve 31 is disconnected, stopping the suction, and the robot arm removes the wafer from the V-groove suction cup pad 10. The controller opens the first water supply valve 22 in the first water supply system 20 corresponding to this workstation, allowing water to flow through the first water spray pipe 21 and through the through-holes on the V-groove suction cup pad 10, spraying water onto its surface. The water flow covers the upper surface of the V-groove suction cup pad 10 in an arc-shaped parabolic pattern, washing away particles or impurities adsorbed on the surface of the suction cup pad. Throughout the local cleaning process, the V-groove suction cup pad 10 remains stationary, and the water spraying continues for 8-12 seconds. After the time is up, the controller closes the first water supply valve, stopping the water spraying, and the local cleaning is complete. Once ready, the robot arm is allowed to place the next wafer into the V-groove processing workstation for polishing.

[0039] For the second type of workstation, the local cleaning involves only rinsing the rotating suction cup pad 40 by the first water supply system 20. Specifically, after the current wafer processing is completed, the vacuum valve 31 is disconnected, stopping the suction, and the robot arm removes the wafer from the rotating suction cup pad 40. The controller opens the first water supply valve 22 in the first water supply system 20 corresponding to this workstation, allowing water to flow through the first spray pipe 21 and through the through holes on the rotating suction cup pad 40 to spray water onto its surface. Simultaneously, the controller controls the rotating suction cup pad 40 to rotate at a preset speed of 135-140 r / min, with 8-12 rotations. The water flow covers the upper surface of the rotating suction cup pad 40 in an arc-shaped parabolic form, rinsing away particles or impurities adsorbed on the surface of the suction cup pad. After 8-12 rotations, the rotation of the rotating suction cup pad 40 is automatically stopped, the first water supply valve 22 is closed, the water spraying stops, and the local cleaning is completed. Once ready, the robotic arm is allowed to place the next wafer into the rotary processing station for polishing.

[0040] The overall cleaning operation is triggered when all stations on the machine are idle after a batch of wafers has completed processing at all stations.

[0041] The controller detects that there are no wafers at any workstation and automatically triggers the overall cleaning program of the entire machine. At the same time, the controller automatically locks the loading port to prevent new wafers from being put in during the overall cleaning process, ensuring safety and cleaning effectiveness.

[0042] Perform the same overall cleaning operation on all Category 1 workstations, which only involves rinsing the V-groove suction cup pads 10 of the first water supply system 20, specifically:

[0043] The controller opens the first water supply valve 22 in the first water supply system 20 corresponding to each V-groove processing station, allowing water to flow through the first spray pipe 21 and through the through holes on the V-groove suction cup pad 10, spraying water onto its surface. The water flow covers the upper surface of the V-groove suction cup pad 10 in an arc-shaped trajectory, washing away particles or impurities adsorbed on the surface of the suction cup pad. Throughout the entire cleaning process, the V-groove suction cup pad 10 remains stationary, and the water spraying continues for 25-30 seconds. After the time is up, the controller closes the first water supply valve, stopping the water spraying, and the overall cleaning is complete.

[0044] The same overall cleaning operation is performed on all second-type workstations. The controller opens the first water supply valve 22 in the first water supply system 20 corresponding to that workstation, allowing water to flow through the first spray pipe 21 and through the through-holes in the rotating suction cup pad 40 to spray water onto its surface. Simultaneously, the controller controls the rotating suction cup pad 40 to start rotating at a preset speed of 135-140 r / min. The controller simultaneously opens the second water supply valve 52 of the second water supply system 50 and drives the upper spray head 54 to rotate at a speed of 450-550 r / min via the rotating carrier 55. The water flow from the first spray pipe 21 covers the upper surface of the rotating suction cup pad 40 in an arc-shaped trajectory, washing away particles or impurities adsorbed on the surface of the suction cup pad. The three second spray pipes 51 spray water simultaneously, cleaning the two rotating upper spray heads 54 and the upper surface of the rotating suction cup pad 40 respectively, with a continuous cleaning time of 25-30 seconds. During this process, the spraying and rotation continue until the overall cleaning is completed.

[0045] After the overall cleaning is completed, the entire polishing equipment returns to standby mode, ready to receive the next batch of wafers for polishing.

[0046] The cleaning method for wafer edge polishing designed in this application implements different cleaning methods for workstations after different processing states. It can clean the suction cup pads and the cleanliness of the entire equipment in a timely and effective manner without affecting the normal production rhythm, ensuring the polishing cleaning effect, significantly reducing the incidence of scratches, and thus improving the polishing quality and production yield of wafers.

[0047] This cleaning method performs localized cleaning after each wafer is processed, effectively removing particles from the chuck pads and reducing the risk of scratches caused by particle accumulation. Simultaneously, it performs overall cleaning when the machine is idle, further ensuring equipment cleanliness and achieving efficient cleaning. By automatically performing cleaning operations after each silicon wafer polishing process, particle accumulation on the chuck pads can be effectively removed, significantly reducing the incidence of wafer scratches and improving wafer yield and equipment utilization.

[0048] The embodiments of this application have been described in detail above. These descriptions are merely preferred embodiments and should not be construed as limiting the scope of this application. All equivalent variations and modifications made within the scope of this application should still fall within the patent coverage of this application.

Claims

1. A cleaning method for polishing the edge of a wafer, characterized in that the steps include... include: After each wafer finishes processing at the current workstation and is removed, and before the next wafer is placed in, a local cleaning operation is automatically performed on that workstation. When the entire batch of wafers is processed and all workstations are idle, an automatic overall cleaning operation is performed on all workstations. The workstation includes at least one first-type workstation and at least one second-type workstation; and the operation methods for partial or overall cleaning of the first-type workstation and the second-type workstation are different.

2. The cleaning method for wafer edge polishing according to claim 1, characterized in that, Both the first type of workstation and the second type of workstation are equipped with a first water supply system; the second type of workstation also includes a second water supply system, and both the second water supply system and the first water supply system spray water onto the upper surface of the suction cup pad.

3. The cleaning method for wafer edge polishing according to claim 2, characterized in that, The local cleaning operation includes: Stop the vacuum valve at the current workstation from drawing air; Turn on the first water supply system to allow water to flow through the holes on the suction cup pad and spray out to rinse the upper surface of the suction cup pad.

4. The cleaning method for wafer edge polishing according to claim 3, characterized in that, During the local cleaning process, the suction cup pads on the first type of workstation remain fixed in place, and the cleaning is stopped after 8-12 seconds.

5. The cleaning method for wafer edge polishing according to claim 4, characterized in that, During localized cleaning, the suction cup pads on the second type of workstation rotate at a preset speed for a certain number of revolutions while being cleaned, and then stop cleaning after reaching the preset number of revolutions; wherein, the suction cup pads on the second type of workstation rotate at a speed of 135-140 r / min and rotate 8-12 times.

6. A cleaning method for polishing wafer edges according to any one of claims 3-5, characterized in that, The overall cleaning operation includes: For the first type of workstation, lock the loading port and turn on the first water supply system to spray water to clean the fixed suction cup pad; For the second type of workstation, the loading port is locked, the first water supply system and the second water supply system are turned on, and the suction cup pad and the upper spray head are simultaneously controlled to rotate while cleaning; wherein, the rotation speed of the suction cup pad is 135-140 r / min, the rotation speed of the upper spray head is 450-550 r / min, and the cleaning ends after 25-30 seconds.

7. The cleaning method for wafer edge polishing according to claim 6, characterized in that, The first water supply system is located below the suction cup pad, and its spray pipe passes through the center of the suction cup pad and sprays water onto its surface.

8. The cleaning method for wafer edge polishing according to claim 6, characterized in that, The second water supply system is located above the suction cup pad and has three water spray pipes, two of which are symmetrically arranged and correspond to the two upper throwing heads; the other water spray pipe passes through the center of the rotating carrier used to fix and drive the upper throwing heads to rotate.

9. A cleaning method for polishing wafer edges according to claim 7, characterized in that, in, During the overall cleaning process, the rotating carrier drives the upper spray head to rotate, and the two rotating upper spray heads are cleaned through the symmetrical water spray pipes at both ends of the second water supply system; the water flow is thrown onto the cover wall surface set outside the upper spray head as the upper spray head rotates; the water spray pipe located in the middle of the second water supply system passes through the center of the rotating carrier, and the water flow is driven by the rotating carrier to disperse and fall onto the upper surface of the suction cup pad to rinse the suction cup pad.

10. A cleaning method for polishing wafer edges according to any one of claims 2-5 and 7-8, characterized in that, The first type of station is a V-groove machining station; the second type of station is a rotary machining station.

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