Wafer edge polishing vacuum chuck polishing cloth precise positioning tool and control method thereof

Abstract

The present application relates to a wafer edge polishing vacuum chuck polishing cloth precise positioning tool and its control method, belongs to the technical field of semiconductor processing tool, including vacuum chuck, polishing cloth and positioning tool, the positioning tool includes positioning stud and integrated quick release taper head, the outer circle of the lower part of the positioning stud is provided with equal division scale corresponding to the radial flow channel of the vacuum chuck, and the radial ray emitter is inserted and embedded between adjacent scales. Insert the positioning tool into the center shaft hole for rough positioning; rotate the fine adjustment to align the equal division scale with the radial flow channel for precise positioning; start the ray emitter to project a visual avoidance reference line on the surface of the chuck; attach the polishing cloth with the reference line as the boundary, so that the fan-shaped ring hole is precisely misaligned with the flow channel; pull out the tool after attaching. By combining mechanical precise positioning with optical visual projection, the invisible flow channel is converted into a clear light boundary, completely eliminating the flow channel obstruction caused by blind attachment of the polishing cloth, ensuring the vacuum degree, and significantly improving the attachment accuracy and efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing tooling technology, specifically to a wafer edge polishing vacuum chuck for precise positioning and control of the polishing process and its control method. Background Technology

[0002] In semiconductor wafer manufacturing processes, wafer edge polishing is a critical step in removing edge burrs, chipping, and microcracks. This step typically uses a vacuum chuck to hold the wafer in place. To ensure uniform vacuum suction and smooth airflow, the end face of the vacuum chuck usually has radial flow channels connected to the central shaft hole. At the same time, to protect the wafer surface from scratches and increase friction, a polishing cloth is attached to the upper end face of the vacuum chuck, and the polishing cloth must have corresponding clearance holes to expose the radial flow channels.

[0003] In the edge polishing process of 300mm (12-inch) wafers, the PEEK vacuum chuck used has 6 vacuum channels radiating outward from the center. The structural design is mature and meets the basic requirements for adsorption and chip removal. However, the existing polishing cloth attachment tooling and positioning methods have the following significant defects: 1. The polishing cloth is easily obstructed, affecting vacuum levels: Polishing cloths are typically soft and often dark or opaque. When attached to the surface of the vacuum chuck, the operator cannot observe the actual position of the bottom radial flow channel through the cloth. If the attachment position is misaligned, the polishing cloth can easily obstruct the radial flow channel, causing airflow obstruction during vacuum adsorption, resulting in a decrease or uneven vacuum level in the chuck. This can lead to weak wafer adhesion, and during high-speed rotary polishing, safety accidents such as wafer ejection or uneven polishing may occur.

[0004] 2. Lack of precise indexing and positioning benchmarks: Existing positioning relies mostly on the operator's visual experience or simple edge alignment, lacking a mechanical indexing benchmark that strictly corresponds to the radial flow channel of the suction cup. This results in the misalignment of the fan-shaped annular holes on the polishing cloth with the flow channel of the suction cup, requiring repeated tearing and re-application, which is inefficient and affects the adhesion of the polishing cloth.

[0005] 3. Traditional positioning fixtures are cumbersome to assemble and disassemble and are prone to damaging the suction cup: Some positioning fixtures that use bolts for locking are cumbersome to operate and time-consuming; moreover, metal fixtures are very easy to scratch or wear the central shaft hole of the vacuum suction cup during frequent insertion, removal and rotation for fine adjustment, which will damage the airtightness of the suction cup.

[0006] Fourth, the attachment efficiency is extremely low: due to the lack of visual guidance and precise positioning, operators need to carefully calibrate repeatedly, and each attachment operation takes a long time, which seriously restricts the production cycle of the semiconductor production line.

[0007] A search of patents and publicly known technologies related to wafer edge polishing, vacuum chuck structures, and polishing cloth mounting and positioning revealed that existing technologies can be mainly divided into three categories: The first category is patents for improving the structure of wafer vacuum chucks. Existing solutions mostly focus on optimizing the flow channel arrangement, vacuum chamber, and sealing structure of 300mm wafer polishing vacuum chucks, with an emphasis on improving adsorption uniformity and chip removal capabilities. They only improve the structure of the chuck body and do not involve the design of a dedicated positioning auxiliary structure for wafer polishing.

[0008] The second category is patents for fixed installation of polishing cloth, which generally adopt methods such as slot limiting, overall pressure plate pressing, and adhesive fixing. These are suitable for large-area whole-surface polishing cloth overall bonding, but cannot be adapted to precise alignment scenarios such as wafer edge polishing ring partial polishing and multi-radial flow channel avoidance.

[0009] The third category consists of patents for conventional semiconductor positioning fixtures, which mostly use mechanical blocks and simple scales for rough positioning of the shape. They can only achieve rough positioning and lack an equal division structure that corresponds one-to-one with the six radial diverging channels of the suction cup. Furthermore, they lack a visual ray projection reference positioning mechanism, which cannot meet the fine operation requirements of precise fabric throwing and avoidance of vacuum channels.

[0010] In summary, among existing patents and industry-known technologies, there is currently no dedicated cloth-spraying positioning tool adapted to the PEEK vacuum chuck of the BBS Kinmei E-300UCS edge polishing machine, nor has a mature solution been developed for precise cloth-spraying avoidance and positioning for multi-divided radial flow channels. Summary of the Invention

[0011] This invention addresses the shortcomings of existing technologies by providing a wafer edge polishing vacuum chuck for precise positioning of polishing cloth and its control method. By combining mechanical precision positioning with optical visualization projection, the invisible flow channels are transformed into clear light boundaries, completely eliminating flow channel obstruction caused by blind polishing cloth application, ensuring vacuum level, and significantly improving application accuracy and efficiency.

[0012] The above-mentioned technical problems of the present invention are mainly solved by the following technical solutions: A precision positioning fixture for wafer edge polishing using a vacuum chuck includes a vacuum chuck with a central shaft hole at its upper end. The upper surface of the vacuum chuck has several radial flow channels communicating with the central shaft hole. A polishing cloth is placed above the vacuum chuck. A positioning fixture for positioning the polishing cloth and for quick-release connection to the central shaft hole is provided. The positioning fixture includes a positioning stud, with a quick-release cone integrated into the lower end of the positioning stud. The lower outer circumference of the positioning stud has several equally spaced graduations corresponding one-to-one with the positions of the radial flow channels and used to calibrate the angular positions of the flow channels.

[0013] Preferably, a radial ray emitter is provided between each of the two adjacent equal divisions and is fitted into the positioning stud. The ray projection direction of the radial ray emitter is consistent with the extension direction of the radial flow channel, so as to form a visual avoidance reference line on the surface of the vacuum chuck.

[0014] Preferably, the radial ray emitter is an insert-mounted independent light-emitting module, which includes a light-emitting element and a power supply module electrically connected to the light-emitting element.

[0015] The light-emitting element emits linear laser light, such as a line laser, which, combined with the diffuse reflection treatment on the surface of the suction cup, forms a clear baseline.

[0016] Preferably, the light-emitting element is a laser lamp bead or an LED lamp bead; the power supply module is a built-in button battery or an electrical connection contact point for an external device power supply.

[0017] Preferably, the polishing cloth is provided with several sets of fan-shaped annular holes arranged in a ring, and the positions of the fan-shaped annular holes are staggered with the radial flow channel so that the radial flow channel is exposed and free from voids.

[0018] Preferably, the positioning stud and the quick-release cone are integrally formed from PEEK material.

[0019] A control method for a precision positioning fixture for wafer edge polishing using a vacuum chuck includes the following steps: S1. Tooling insertion and coarse positioning: Align the quick-release cone of the positioning tooling with the central shaft hole of the vacuum chuck and insert it to form a plug-in quick-release connection between the positioning tooling and the vacuum chuck.

[0020] S2. Indexing and fine positioning: Rotate the fine-tuning positioning fixture to precisely align the equal divisions on the outer circle of the positioning stud with the radial flow channels on the vacuum chuck, thus establishing a mechanical indexing reference.

[0021] S3, Reference Visualization Projection: Activate the radial ray emitter on the positioning fixture to project a visual avoidance reference line on the upper surface of the vacuum chuck along the extension direction of the radial flow channel.

[0022] S4. Precise Avoidance Attachment: Using the visual avoidance baseline as a boundary reference, attach the polishing cloth to the area between two adjacent visual avoidance baselines, so that the fan-shaped annular holes on the polishing cloth are precisely misaligned with the radial flow channel.

[0023] S5. Tooling disassembly and restoration: After the polishing cloth is attached, turn off the X-ray emitter, pull the positioning tooling out of the central shaft hole, and the vacuum chuck enters the wafer edge polishing operation state.

[0024] Preferably, in step S2, the center symmetry line of the equally divided scale coincides with the center line of the radial flow channel.

[0025] Preferably, in step S3, when the visual avoidance baseline is projected onto the upper surface of the vacuum suction cup (1), the coverage trajectory of the baseline completely coincides with the trajectory of the radial flow channel, and the projection length of the baseline covers the entire adsorption surface of the vacuum suction cup.

[0026] The present invention can achieve the following effects: This invention provides a precision positioning fixture and control method for wafer edge polishing vacuum chucks and polishing cloth. Compared with existing technologies, the flow channels of wafer polishing chucks are extremely narrow, and traditional visual or mechanical alignment cannot solve the problem of blind spots caused by the polishing cloth covering the flow channels. By pre-defining the avoidance boundary through light projection before attachment, combined with the specific fan-shaped annular hole structure of the polishing cloth, zero obstruction is achieved in high-precision semiconductor processes. It has the following significant advantages: I. Transforming the Invisible into the Visible for Precise Avoidance and Guaranteed Vacuum: An innovative radial ray emitter is integrated into the positioning fixture. Before the polishing cloth is applied, the invisible radial flow channel positions are projected directly onto the vacuum suction cup surface as a "visual avoidance baseline." The operator uses the light as a "no-go zone" boundary for application, intuitively and clearly ensuring the precise misalignment of the polishing cloth's fan-shaped annular holes with the flow channel. This completely eliminates flow channel obstruction caused by blind application, guaranteeing smooth airflow and stable vacuum levels.

[0027] II. Dual Positioning Mechanism for High-Precision Mechanical Indexing Reference: A dual mechanism of "quick-release cone head coarse positioning + equally divided scale fine positioning" is employed. The quick-release cone head inserts into the central shaft hole for rapid concentric positioning; fine-tuning by rotation aligns the equally divided scale with the flow channel centerline, establishing a precise angular indexing reference. Mechanical positioning and optical projection complement each other, significantly improving positioning accuracy and eliminating human visual error.

[0028] 3. Quick-release non-metallic structure, damage-proof and efficient: The positioning fixture adopts a quick-release cone head design, which tightens upon insertion and releases upon removal, achieving disassembly and assembly in seconds; at the same time, the positioning stud and the quick-release cone head are integrally molded from PEEK material, which not only ensures structural strength, but also utilizes the self-lubricating and buffering properties of PEEK to avoid wear on the central shaft hole of the vacuum chuck during insertion and removal, thus extending the service life of the expensive chuck.

[0029] IV. Modular light-emitting design, convenient maintenance and strong adaptability: The radial ray emitter adopts an insert-type independent light-emitting module (T-slot / dovetail slot combination). When a lamp is damaged, there is no need to replace the entire tooling. It can be replaced by pulling out and plugging in one lamp, which greatly reduces maintenance costs. The power supply method supports both built-in button battery for convenient wireless operation and external contact point power supply, adapting to different working environments.

[0030] V. Significantly Improved Operational Efficiency: Utilizing precise mechanical positioning and clear optical projection boundaries, operators no longer need to repeatedly test-place and peel off calibrations. A single complete operation cycle (from tooling insertion to final removal) can be controlled within 1 minute. Compared to traditional blind placement methods, this represents a qualitative leap in efficiency, effectively meeting the high-speed production demands of semiconductor production lines. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the present invention.

[0032] Figure 2 This is a cross-sectional view of the structure of the present invention.

[0033] Figure 3 This is a schematic diagram of the structure of the vacuum suction cup of the present invention.

[0034] Figure 4 This is a schematic diagram of the structure of the polishing cloth of the present invention.

[0035] Figure 5 This is a schematic diagram of the positioning tooling of the present invention.

[0036] Figure 6 This is a schematic diagram of the structure of the ray emitter of the present invention.

[0037] In the diagram: 1. Vacuum suction cup; 2. Polishing cloth; 3. Positioning fixture; 4. Radial flow channel; 5. Central shaft hole; 6. Fan-shaped annular hole; 7. Positioning stud; 8. Radial ray emitter; 9. Divided scale; 10. Quick-release cone; 11. Power supply module; 12. Light-emitting element. Detailed Implementation

[0038] The technical solution of the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0039] Example: Figure 1-6As shown, a precision positioning fixture for wafer edge polishing using a vacuum chuck includes a vacuum chuck 1, a polishing cloth 2, and a positioning fixture 3. The vacuum chuck 1 has a central shaft hole 5 at its upper center, and six radial flow channels 4 evenly distributed on its upper surface, communicating with the central shaft hole 5. The vacuum chuck 1 is covered with the polishing cloth 2, which has six sets of six fan-shaped annular holes 6 arranged in a ring. During assembly, the fan-shaped annular holes 6 must be staggered with the radial flow channels 4 to allow the radial flow channels 4 to be exposed and prevent airflow, ensuring smooth airflow during vacuum adsorption.

[0040] A positioning fixture 3 is provided on the central shaft hole 5 to position the polishing cloth 2 and is connected to the central shaft hole 5 in a quick-release plug-in manner. Specifically, the positioning fixture 3 includes a positioning stud 7, and the lower end of the positioning stud 7 is provided with a quick-release cone 10 integrated with the positioning stud 7. Preferably, the positioning stud 7 and the quick-release cone 10 are integrally molded from PEEK material, which ensures structural strength and avoids wear on the central shaft hole 5 of the vacuum chuck 1 during insertion and removal. The cone surface design of the quick-release cone 10 can automatically guide and tighten when inserted into the central shaft hole 5, realizing quick insertion and removal and stable positioning.

[0041] To establish a mechanical indexing reference, the lower outer circumference of the positioning stud 7 is provided with several equally spaced graduations 9 that correspond one-to-one with the positions of the radial flow channels 4. During indexing calibration, the central symmetry line of the equally spaced graduations 9 coincides with the center line of the radial flow channels 4, thereby establishing a precise mechanical indexing reference.

[0042] Furthermore, a radial ray emitter 8 is provided between each of the two adjacent equally spaced graduations 9, and is fitted into the positioning stud 7. Specifically, a T-slot or dovetail groove extending radially can be formed on the positioning stud 7, and the housing of the radial ray emitter 8 is provided with a matching slide rail. The fitting of the slide rail and the groove achieves the insertion assembly, which not only ensures positioning accuracy but also facilitates individual replacement in case of damage. The ray projection direction of the radial ray emitter 8 is consistent with the extension direction of the radial flow channel 4, thereby forming a visible avoidance reference line on the upper surface of the vacuum chuck 1.

[0043] In this embodiment, the radial ray emitter 8 is an independent light-emitting module with an insert-type assembly. The light-emitting module includes a light-emitting element 12 and a power supply module 11 electrically connected to the light-emitting element 12. The light-emitting element 12 can be a laser lamp bead or an LED lamp bead; the power supply module 11 can be a built-in button battery to enable wireless and convenient operation, or it can be an electrical connection contact point for an external device power supply.

[0044] Based on the above tooling structure, the present invention also provides a control method for the precise positioning tooling of the wafer edge polishing vacuum chuck, which specifically includes the following operation steps: S1. Tooling insertion and rough positioning: Align the quick-release cone 10 of the positioning tool 3 with the central shaft hole 5 of the vacuum chuck 1 and insert it. Utilize the guiding effect of the cone surface to form a plug-in quick-release connection between the positioning tool 3 and the vacuum chuck 1, thus completing the preliminary positioning.

[0045] S2. Indexing and fine positioning: Rotate the fine-tuning positioning fixture 3 to make the equal division scale 9 on the outer circle of the positioning stud 7 precisely aligned with the radial flow channel 4 on the vacuum chuck 1 (that is, the center symmetry line of the equal division scale 9 coincides with the center line of the radial flow channel 4), thereby establishing a mechanical indexing reference.

[0046] S3. Reference Visualization Projection: Activate the radial ray emitter 8 on the positioning fixture 3 to project a visual avoidance reference line onto the upper surface of the vacuum suction cup 1 along the extension direction of the radial flow channel 4. Preferably, when the reference line is projected onto the upper surface of the vacuum suction cup 1, the coverage trajectory of the reference line basically coincides with the trajectory of the radial flow channel 4, and the projection length of the reference line covers the entire adsorption surface of the vacuum suction cup 1, forming a clearly visible "no-go zone" boundary.

[0047] S4. Precise Avoidance Attachment: Using the visual avoidance baseline as a boundary reference, attach the polishing cloth 2 within the safe area between two adjacent visual avoidance baselines. During the attachment process, the operator can clearly observe the light projection position, thereby ensuring that the fan-shaped annular holes 6 on the polishing cloth 2 are precisely misaligned with the radial flow channel 4, preventing the polishing cloth 2 from obstructing the flow channel and affecting the vacuum level.

[0048] S5. Fixture Disassembly and Restoration: After the polishing cloth 2 is fully attached, turn off the radial ray emitter 8 and pull the positioning fixture 3 out of the central shaft hole 5. At this time, the vacuum chuck 1 can enter the wafer edge polishing operation state. Using the above method, the cycle time of a single complete operation can be controlled within 1 minute, which greatly improves the attachment efficiency and accuracy.

[0049] In summary, the wafer edge polishing vacuum chuck precision positioning fixture and its control method combine mechanical precision positioning with optical visualization projection to transform invisible flow channels into clear light boundaries, completely eliminating flow channel obstruction caused by blind placement of polishing cloth, ensuring vacuum level, and significantly improving placement accuracy and efficiency.

[0050] The above description is only a specific embodiment of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A precision positioning fixture for wafer edge polishing using a vacuum chuck, characterized in that: The device includes a vacuum suction cup (1), which has a central shaft hole (5) at its upper end. The upper surface of the vacuum suction cup (1) has several radial flow channels (4) that are connected to the central shaft hole (5). A polishing cloth (2) is provided above the vacuum suction cup (1). A positioning fixture (3) is provided on the central shaft hole (5) to position the polishing cloth (2) and to be quickly and easily connected to the central shaft hole (5). The positioning fixture (3) includes a positioning stud (7). The lower end of the positioning stud (7) has a quick-release cone (10) that is integrated with the positioning stud (7). The lower outer circle of the positioning stud (7) has several equally divided scales (9) that correspond one-to-one with the positions of the radial flow channels (4) and are used to calibrate the angle positions of the flow channels.

2. The wafer edge polishing vacuum chuck precision positioning fixture according to claim 1, characterized in that: Between each of the two adjacent equal divisions (9), there is a radial ray emitter (8) that is inserted into the positioning stud (7). The ray projection direction of the radial ray emitter (8) is consistent with the extension direction of the radial flow channel (4) to form a visual avoidance baseline on the surface of the vacuum chuck (1).

3. The wafer edge polishing vacuum chuck precision positioning fixture according to claim 2, characterized in that: The radial ray emitter (8) is an independent light-emitting module with plug-in assembly. The light-emitting module includes a light-emitting element (12) and a power supply module (11) electrically connected to the light-emitting element (12).

4. The wafer edge polishing vacuum chuck precision positioning fixture according to claim 3, characterized in that: The light-emitting element (12) is a laser lamp bead or an LED lamp bead; the power supply module (11) is a built-in button battery or an electrical connection contact point for an external device power supply.

5. The wafer edge polishing vacuum chuck precision positioning fixture according to claim 1, characterized in that: The polishing cloth (2) is provided with a number of fan-shaped annular holes (6) arranged in a ring. The position of the fan-shaped annular holes (6) is staggered with that of the radial flow channel (4) so ​​that the radial flow channel (4) is exposed and free from air.

6. The wafer edge polishing vacuum chuck precision positioning fixture according to claim 1, characterized in that: The positioning stud (7) and quick-release cone (10) are integrally formed using PEEK material.

7. A control method for the wafer edge polishing vacuum chuck precision positioning fixture according to claim 2, characterized in that... The following steps are included: S1. Tooling insertion and rough positioning: Align the quick-release cone (10) of the positioning tool (3) with the central shaft hole (5) of the vacuum chuck (1) and insert it to form a plug-in quick-release connection between the positioning tool (3) and the vacuum chuck (1). S2, Indexing and fine positioning: Rotate the fine-tuning positioning fixture (3) to make the equal division scale (9) on the outer circle of the positioning stud (7) and the radial flow channel (4) on the vacuum chuck (1) precisely aligned to establish a mechanical indexing reference; S3, Reference Visualization Projection: Activate the radial ray emitter (8) on the positioning fixture (3) to project a visual avoidance reference line on the upper surface of the vacuum chuck (1) along the extension direction of the radial flow channel (4); S4. Precise avoidance attachment: Using the visual avoidance baseline as a boundary reference, attach the polishing cloth (2) to the area between two adjacent visual avoidance baselines, so that the fan-shaped annular hole (6) on the polishing cloth (2) is precisely misaligned with the radial flow channel (4); S5. Tooling disassembly and restoration: After the polishing cloth (2) is attached, turn off the X-ray emitter (8), pull out the positioning tool (3) from the central shaft hole (5), and the vacuum chuck (1) enters the wafer edge polishing operation state.

8. The control method for the wafer edge polishing vacuum chuck precision positioning fixture according to claim 7, characterized in that: In step S2, the center symmetry line of the equally divided scale (9) coincides with the center line of the radial flow channel (4).

9. The control method for the wafer edge polishing vacuum chuck precision positioning fixture according to claim 7, characterized in that: In step S3, when the visual avoidance baseline is projected onto the upper surface of the vacuum chuck (1), the coverage trajectory of the baseline completely coincides with the trajectory of the radial flow channel (4), and the projection length of the baseline covers the entire adsorption surface of the vacuum chuck (1).

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