A polishing pad cleaning device

Abstract

The application provides a polishing pad cleaning device, which comprises a cleaning disc and a rinsing liquid supply unit; a plurality of mechanical stripping units are arranged on the side surface of the cleaning disc close to the polishing pad, the hardness of the mechanical stripping units is greater than that of the polishing pad base material, and the mechanical stripping units are used for cutting and removing the accumulated substances on the surface of the polishing pad; the rinsing liquid supply unit is used for supplying rinsing liquid to the surface of the polishing pad and synchronously removing the debris generated by the mechanical stripping; the cleaning disc is arranged in a hollow cavity in the interior of a polishing head, and a telescopic mechanism is arranged in the hollow cavity and used for driving the cleaning disc to move in the axial direction. The polishing pad cleaning device can effectively trim the polishing pad during the wafer edge polishing process by the combined mode of the cleaning disc and the rinsing liquid supply unit, efficiently removes the residual accumulated substances on the polishing pad, and significantly improves the processing quality and the yield of the wafer edge polishing; the cleaning disc is integrated in the interior of the polishing head, and no additional external space of the equipment is occupied, so that the overall structural layout of the equipment is simplified.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor manufacturing technology, and specifically to a polishing pad cleaning device. Background Technology

[0002] In semiconductor wafer edge polishing processes, the wafer is supported by an edge polishing chuck, and the polishing is achieved through contact between the polishing pad, which is adsorbed onto the surface of the chuck, and the polishing tool. The polishing pad, due to its porous structure, can store polishing fluid to maintain the chemical reaction.

[0003] However, as polishing continues, abrasive particles (such as silica and cerium oxide) and reaction byproducts (such as silicate gel) in the polishing slurry remain in the pores, forming hard deposits, resulting in two major defects: pore blockage and deterioration of smoothness.

[0004] Pore ​​blockage refers to the accumulation of deposits filling pores, causing the polishing pad to lose its liquid retention capacity and resulting in a localized increase in surface hardness. When a wafer is picked up by a chuck and placed onto an uneven polishing pad, localized stress concentration occurs, causing microcracks or edge chipping in the edge area.

[0005] Flatness degradation refers to the height difference between clogged and unclogged areas, resulting in an uneven surface on the polishing pad. Uneven polishing pressure distribution leads to excessive thickness deviation at the wafer edges, causing a decrease in yield.

[0006] In existing technologies, manual cleaning or replacement of polishing pads is generally carried out by stopping the machine. However, stopping the machine for cleaning will reduce the utilization rate of the equipment, while frequent replacement of polishing pads will increase production costs. Utility Model Content

[0007] Given that existing technologies often result in polishing slurry residue buildup on the surface and in the pores of the polishing pad, which can easily lead to wafer defects and affect wafer processing quality and yield, this application provides a polishing pad cleaning device. This device, through a combination of a cleaning disc and a rinsing fluid supply unit, can periodically and effectively clean the polishing pad during wafer edge polishing, achieving efficient removal of residual buildup and fundamentally ensuring the flatness of the polishing pad surface. This significantly improves the processing quality and yield of wafer edge polishing. Furthermore, by integrating the cleaning disc within the polishing head structure, it eliminates the need for additional external space in the polishing equipment, simplifying the overall structural layout.

[0008] This application provides a polishing pad cleaning device, comprising:

[0009] A cleaning disc, wherein multiple mechanical peeling units are provided on the side surface of the cleaning disc near the polishing pad, the hardness of the mechanical peeling units being greater than the hardness of the polishing pad substrate, for cutting and removing deposits on the surface of the polishing pad.

[0010] A rinsing fluid supply unit is used to supply rinsing fluid to the surface of the polishing pad to simultaneously remove debris generated by mechanical peeling.

[0011] The cleaning disc is disposed inside the hollow cavity of the polishing head, and a telescopic mechanism is provided inside the hollow cavity to drive the cleaning disc to move axially.

[0012] In one embodiment, the axis of the cleaning disc coincides with the axis of the hollow cavity.

[0013] In one embodiment, the telescopic mechanism includes a hydraulic cylinder and a hollow piston rod. A seal is provided at the mating point between the cylinder body of the hydraulic cylinder and the hollow piston rod. The driving end of the hollow piston rod is connected to the center of the cleaning disc.

[0014] In one embodiment, the rinsing fluid supply unit includes a first rinsing fluid channel disposed within the hollow piston rod, a second rinsing fluid channel disposed at the center of the cleaning disc, and a third rinsing fluid channel disposed at the center of the polishing pad and the polishing disc; the first rinsing fluid channel is connected to the second rinsing fluid channel, and the axis of the second rinsing fluid channel coincides with the axis of the third rinsing fluid channel.

[0015] In one embodiment, the cross-sectional dimensions of the cleaning disc are the same as those of the polishing pad.

[0016] In one embodiment, the rotation direction of the cleaning disc is opposite to the rotation direction of the polishing pad.

[0017] In one embodiment, the mechanical stripping unit is at least one of diamond particles, cubic boron nitride particles, or silicon carbide microcrystal protrusions.

[0018] As described above, the polishing pad cleaning device of this application has the following beneficial effects:

[0019] The polishing pad cleaning device of this application, through the combination of a cleaning disc and a rinsing fluid supply unit, can effectively and periodically clean the polishing pad during wafer edge polishing. The cleaning disc, with its mechanical stripping unit, precisely removes residual deposits from the polishing pad, while the rinsing fluid supply unit promptly removes debris generated by the mechanical stripping, achieving efficient removal of residual deposits and preventing pore blockage caused by these deposits. This fundamentally ensures the flatness of the polishing pad surface, thereby reducing the risk of defects caused by uneven polishing pads during wafer processing and significantly improving the processing quality and yield of wafer edge polishing. Integrating the cleaning disc within the structure of the inherent polishing head eliminates the need for additional external space in the polishing equipment. This cleverly utilizes the unused space inside the polishing head, simplifying the overall structural layout of the equipment and avoiding the problems of increased equipment size or space interference caused by adding a cleaning disc. This is particularly suitable for semiconductor polishing equipment scenarios with limited space. Attached Figure Description

[0020] Figure 1 The diagram shown is a structural schematic of the polishing pad cleaning device according to an embodiment of the present invention.

[0021] Figure 2 The diagram shown is a structural schematic of the cleaning tray according to an embodiment of the present invention.

[0022] Component designation explanation

[0023] 10, Polishing pad; 20, Polishing disc; 30, Polishing head; 100, Cleaning disc; 110, Mechanical stripping unit; 200, Rinse fluid supply unit; 210, First rinse fluid channel; 220, Second rinse fluid channel; 230, Third rinse fluid channel; 300, Telescopic mechanism; 310, Hydraulic cylinder; 320, Hollow piston rod. Detailed Implementation

[0024] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0025] Please see Figures 1 to 2 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the illustrations only show the components related to this utility model and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0026] In wafer edge polishing, the wafer is typically held by an edge polishing chuck and polished using a polishing pad. The polishing pad, a critical processing component, has a porous surface structure, which should play a vital role in the polishing process. However, as processing continues, polishing fluid gradually accumulates on the pad's surface and within its pores, forming deposits. These deposits can clog the pad's pores, causing the surface to lose its original smoothness. When a wafer is processed using a polishing pad with an uneven surface, defects are highly likely to occur, affecting wafer processing quality and yield.

[0027] To address the above-mentioned shortcomings, this application provides a polishing pad cleaning device. The following embodiments will provide a detailed description.

[0028] This embodiment provides a polishing pad cleaning device, such as... Figure 1 and Figure 2 As shown, the polishing pad cleaning device includes a cleaning disc 100 and a rinsing fluid supply unit 200.

[0029] Among them, such as Figure 2 As shown, a plurality of mechanical peeling units 110 are provided on the side surface of the cleaning disc 100 near the polishing pad 10. The hardness of the mechanical peeling units 110 is greater than the hardness of the substrate of the polishing pad 10, and they are used to cut and remove the deposits on the surface of the polishing pad 10.

[0030] The rinsing fluid supply unit 200 is used to supply rinsing fluid to the surface of the polishing pad 10 to simultaneously remove debris generated by mechanical peeling.

[0031] The polishing pad cleaning device provided in this embodiment, through the combination of a cleaning disc 100 and a rinsing fluid supply unit 200, can effectively and periodically clean the polishing pad 10 during wafer edge polishing. The cleaning disc 100, with its mechanical stripping unit 110, can precisely remove residual deposits on the polishing pad 10, while the rinsing fluid supply unit 200 promptly removes debris generated by the mechanical stripping, achieving efficient removal of residual deposits from the polishing pad 10. This avoids clogging of the pores in the polishing pad 10 caused by deposits, fundamentally ensuring the flatness of the polishing pad 10 surface. This reduces defects caused by unevenness of the polishing pad 10 during wafer processing, significantly improving the processing quality and yield of wafer edge polishing.

[0032] like Figure 1As shown, the cleaning disc 100 is disposed within the hollow cavity inside the polishing head 30. A telescopic mechanism 300 is installed within the hollow cavity, which drives the cleaning disc 100 to move axially. This embodiment integrates the cleaning disc 100 within the inherent structure of the polishing head 30, eliminating the need for additional external space on the polishing equipment. It cleverly utilizes the unused space inside the polishing head 30, simplifying the overall structural layout of the equipment and avoiding the increased equipment size or spatial interference issues caused by adding the cleaning disc 100. This is particularly suitable for space-constrained semiconductor polishing equipment scenarios. By setting up a telescopic mechanism 300, the stability and continuity of the polishing process are improved. The design of the telescopic mechanism 300 allows the cleaning disc 100 to flexibly extend and retract according to processing needs. When cleaning is required, the cleaning disc 100 extends to contact the polishing pad 10 for operation. After cleaning is completed, the cleaning disc 100 retracts into the polishing head 30 without affecting the normal polishing process. This on-demand working mode ensures the orderly switching between polishing and cleaning operations, avoids processing interruptions caused by setting up a separate cleaning process, improves the operating efficiency of the equipment and the stability of polishing quality, thereby reducing the defect rate in the wafer processing process and increasing the yield.

[0033] In optional embodiments, such as Figure 1 As shown, the axis of the cleaning disc 100 coincides with the axis of the hollow cavity. This reduces vibration and unbalanced forces, improves operational stability and equipment reliability, and ensures that the cleaning force (pressure, friction) applied to the surface of the polishing pad 10 is more uniform, thereby achieving a more consistent and controllable cleaning effect and avoiding localized damage or insufficient cleaning. At the same time, it simplifies mechanical design, installation calibration and maintenance, and improves the durability and lifespan of the equipment.

[0034] In optional embodiments, such as Figure 1 As shown, the telescopic mechanism 300 includes a hydraulic cylinder 310 and a hollow piston rod 320. A seal is provided at the mating point between the cylinder body of the hydraulic cylinder 310 and the hollow piston rod 320. The driving end of the hollow piston rod 320 is connected to the center of the cleaning tray 100. The flushing fluid supply unit 200 includes a first flushing fluid channel 210 disposed within the hollow piston rod 320 and a second flushing fluid channel 220 disposed at the center of the cleaning tray 100 (e.g., ...). Figure 2 (as shown), and a third flushing fluid channel 230 located at the center of the polishing pad 10 and the polishing disk 20.

[0035] Specifically, the hydraulic cylinder 310 adopts a double-chamber design, with an inner hollow piston rod 320 and an outer pneumatic or hydraulic chamber. The hollow piston rod 320 is threadedly connected to the cleaning disc 100, and a radial through hole is provided at the connection to allow for the flow of flushing fluid. The seal can be a combination of Step seals and O-rings, ensuring the sealing of the pneumatic or hydraulic chamber while preventing flushing fluid leakage from the gap between the hollow piston rod 320 and the cylinder body. The end of the cylinder body away from the cleaning disc 100 can be connected to an external flushing fluid pipeline via a quick-connect fitting, independently arranged from the pneumatic or hydraulic interface. When the hollow piston rod 320 drives the cleaning disc 100 to extend and contact the polishing pad 10, the flushing fluid is sprayed out through the first flushing fluid channel 210 of the hollow piston rod 320 and the second flushing fluid channel 220 within the cleaning disc 100; during retraction, the flushing fluid can be simultaneously controlled by a solenoid valve. The flushing fluid can be water, etc. After the rinsing fluid is sprayed from the first rinsing fluid channel 210 and the second rinsing fluid channel 220 onto the surface of the polishing pad 10, the liquid flows out from the third rinsing fluid channel 230 after cleaning the surface of the polishing pad 10.

[0036] In an optional embodiment, the cross-sectional dimensions of the cleaning disc 100 are the same as those of the polishing pad 10. Since both the cleaning disc 100 and the polishing pad 10 are cylindrical structures (their thicknesses may differ), the surfaces of the cleaning disc 100 and the polishing pad 10 adjacent to the cleaning disc 100 are circular, and both surfaces have the same diameter. This size matching ensures that the cleaning disc 100 can cover the entire effective working area of ​​the polishing pad 10 during cleaning, avoiding residue buildup at the edges or corners of the polishing pad 10 due to an excessively small size, or wasted cleaning areas due to an excessively large size. This full-coverage finishing method ensures consistent wear and flatness across the surface of the polishing pad 10, effectively eliminating localized pore blockage or surface unevenness, and improving the overall uniformity of the polishing pad 10's performance.

[0037] In an optional embodiment, the rotation direction of the cleaning disc 100 is opposite to that of the polishing pad 10. The axis of the cleaning disc 100 coincides with or is parallel to the axis of the polishing pad 10. Since the rotation directions are opposite, the cleaning disc 100 and the polishing pad 10 form a reverse relative motion, and the resulting shear force and friction force are much greater than the force when rotating in the same direction. This reverse motion can more effectively remove polishing liquid particles, debris and other deposits remaining on the surface and in the pores of the polishing pad 10, especially forming a stronger cleaning effect on stubborn residues attached to the inner wall of the pores, and reducing the residence time of residues on the surface of the polishing pad 10.

[0038] In an optional embodiment, the mechanical stripping unit 110 is at least one of diamond particles, cubic boron nitride particles, or silicon carbide microcrystalline protrusions. It is understood that, in order to achieve a better cleaning effect and avoid damage to the polishing pad 10 itself, the mechanical stripping unit 110 may have multiple irregular or polyhedral shapes with moderately sharp edges and micro-cutting blades, such as broken irregular shapes, cubic-like shapes, octahedrons, polyhedrons with obvious edges, etc. However, sharp, needle-like, and sheet-like shapes should be avoided to prevent excessive damage to the polishing pad 10, and round, spherical shapes should also be avoided to prevent unsatisfactory cleaning results.

[0039] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A polishing pad cleaning device, characterized in that, include: A cleaning disc, wherein multiple mechanical peeling units are provided on the side surface of the cleaning disc near the polishing pad, the hardness of the mechanical peeling units being greater than the hardness of the polishing pad substrate, for cutting and removing deposits on the surface of the polishing pad. A rinsing fluid supply unit is used to supply rinsing fluid to the surface of the polishing pad to simultaneously remove debris generated by mechanical peeling. The cleaning disc is disposed inside the hollow cavity of the polishing head, and a telescopic mechanism is provided inside the hollow cavity to drive the cleaning disc to move axially.

2. The polishing pad cleaning device according to claim 1, characterized in that, The axis of the cleaning disc coincides with the axis of the hollow cavity.

3. The polishing pad cleaning device according to claim 1 or 2, characterized in that, The telescopic mechanism includes a hydraulic cylinder and a hollow piston rod. A seal is provided at the mating point between the cylinder body of the hydraulic cylinder and the hollow piston rod. The driving end of the hollow piston rod is connected to the center of the cleaning disc.

4. The polishing pad cleaning device according to claim 3, characterized in that, The rinsing fluid supply unit includes a first rinsing fluid channel disposed within the hollow piston rod, a second rinsing fluid channel disposed at the center of the cleaning disc, and a third rinsing fluid channel disposed at the center of the polishing pad and the polishing disc; the first rinsing fluid channel is connected to the second rinsing fluid channel, and the axis of the second rinsing fluid channel coincides with the axis of the third rinsing fluid channel.

5. The polishing pad cleaning device according to claim 1, characterized in that, The cross-sectional dimensions of the cleaning disc are the same as those of the polishing pad.

6. The polishing pad cleaning device according to claim 1, characterized in that, The cleaning disc rotates in the opposite direction to the polishing pad.

7. The polishing pad cleaning device according to claim 1, characterized in that, The mechanical peeling unit is at least one of diamond particles, cubic boron nitride particles, or silicon carbide microcrystal protrusions.

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