A cleaning-liquid supply integrated device and an on-line cleaning method for polyurethane polishing pads

Abstract

An integrated cleaning and liquid supply device and online cleaning method for polyurethane polishing pads are disclosed. The device includes a base, a rotating seat, a swing arm, an independent liquid supply pipeline system and cleaning pipeline, a high-pressure nozzle array, and a positioning sensor assembly. During the polishing stage, polishing liquid is dripped through the liquid supply outlet. During the cleaning stage, the swing arm moves centripetally to a preset position aligned with the center of the polishing pad. The positioning sensor triggers a high-pressure pump, causing pure water to be sprayed as an atomized jet along the diameter of the pad surface through the high-pressure nozzle array. Simultaneously, the polishing pad rotates at a low speed, utilizing the synergistic effect of centrifugal force and high-pressure water flow to thoroughly remove residual contaminants within the micropores of the polyurethane. This invention integrates liquid supply and deep cleaning functions into the same motion mechanism, eliminating the need for machine shutdown or manual intervention. It offers advantages such as non-contact, non-destructive, thorough cleaning, and high automation, extending the life of the polishing pad and improving the stability of the CMP process.

Description

Technical Field

[0001] This invention belongs to the field of chemical mechanical polishing equipment, specifically relating to an integrated cleaning-liquid supply device and online cleaning method for polyurethane polishing pads. Background Technology

[0002] In Chemical Mechanical Polishing (CMP) processes, the polishing pad (typically made of porous polyurethane material) is a crucial interface for achieving global planarization of workpieces such as wafers and glass substrates. Its porous cavity structure is essential for storing and uniformly distributing the polishing slurry during polishing, directly affecting material removal rate and polishing uniformity. However, after the polishing process, a large amount of polishing slurry, chemical reaction products, and removed material debris (collectively referred to as polishing waste) inevitably remain on the surface and internal cavities of the polishing pad. If these residues are not effectively removed, they will cause scratches and contamination in subsequent polishing processes, leading to uncontrollable changes in the surface properties of the polishing pad (such as roughness and hardness), severely affecting process stability and product yield, while also shortening the lifespan of the expensive polishing pad.

[0003] Currently, the industry commonly uses mechanical brushing for the maintenance and cleaning of polishing pads, which involves using contact brushes such as nylon brushes or PVA brushes to scrape and clean the surface of the polishing pad. This method has the following inherent drawbacks: The cleaning process suffers from significant blind spots: the brushing force is limited to the outermost layer of the polishing pad, failing to penetrate deep into the cavities and deeper areas within the polyurethane material. This leads to the long-term accumulation of polishing fluid and fine debris in these areas, forming "deep residue" that becomes a potential source of contamination affecting polishing consistency and causing defects.

[0004] The force applied during the brushing process is uncontrollable and easily causes damage: The force applied to the pad during the brushing process is affected by various factors such as brush bristle wear, brush pressure, and pad surface humidity, making it difficult to maintain a constant force. Excessive or uneven force can directly scratch or excessively wear down the microstructure of the polishing pad surface, damaging its flatness and liquid retention capacity, which violates the core premise of the cleaning operation: "do not damage the pad surface".

[0005] Single function: Traditional cleaning equipment is independent of the liquid supply system, which increases the complexity of equipment layout and floor space, and also increases the number of process switching links, affecting the overall operating efficiency and automation integration of the equipment.

[0006] Therefore, developing an integrated device that can perform deep, non-destructive cleaning of polyurethane polishing pads and can be efficiently integrated with the liquid supply process is an urgent technical need and has significant industrial value for improving the overall efficiency of CMP processes, reducing costs, and ensuring product quality. Summary of the Invention

[0007] In view of the deficiencies in the prior art, the technical problems to be solved by the present invention are reflected in the following points.

[0008] 1. Solves the problem that traditional brushing methods cannot completely remove residues from the cavities of polyurethane polishing pads; 2. Integrate cleaning and liquid supply functions to reduce equipment complexity and cost; 3. Avoid damaging the polishing pad surface by using controlled cleaning methods.

[0009] The technical solution of the present invention is as follows: On one hand, the present invention provides an integrated cleaning-liquid supply device for polyurethane polishing pads, characterized in that it includes: The base, used to fix the equipment to the frame of the chemical mechanical polishing equipment, has a hollow channel inside; A rotating seat is rotatably mounted on the base and has a hollow channel inside; The swing arm is connected to the rotating base at one end and can swing along the radial direction of the polishing disc, while the other end is equipped with a high-pressure nozzle array. The dual-mode fluid supply system includes an independent liquid supply path and a cleaning path, both of which are installed in the hollow channels of the base, the rotating seat, and the swing arm. The liquid supply path has a liquid supply outlet at its end for supplying polishing liquid to the polishing pad. The cleaning path is connected to the high-pressure nozzle array at its end for supplying high-pressure cleaning medium to the high-pressure nozzle array. A position sensor assembly, mounted on the rotating base, is used to detect whether the swing arm has swung to a preset cleaning start position; and The control system is communicatively connected to the dual-mode fluid supply system, the positioning sensor assembly, and the drive mechanism that drives the rotary seat and the swing arm, and is configured as follows: In the polishing operation mode, the liquid supply path is opened, and polishing liquid is supplied to the polishing pad through the swing arm; In the cleaning operation mode, the swing arm is controlled to swing towards the center of the polishing pad, and based on the detection signal of the positioning sensor component, the swing arm is controlled to stop at the cleaning start position; then, the cleaning flow path is opened, so that the high-pressure cleaning medium is sprayed out through the high-pressure nozzle array, while the polishing pad is controlled to rotate, so that the fixed spray of the high-pressure nozzle array and the rotational motion of the polishing pad are combined to achieve dynamic, non-contact high-pressure rinsing of the entire polishing pad surface.

[0010] Furthermore, the positioning sensor assembly includes: A sensor mounting base is fixed to the side wall of the rotating base; a positioning sensor is mounted on the sensor mounting base; and The corresponding triggering component is disposed on the base; The detection end of the positioning sensor is positioned towards the triggering component. When the swing arm swings to the cleaning start position, the positioning sensor is opposite to the triggering component and generates a positioning signal.

[0011] Furthermore, the sensor mounting base is provided with a waist-shaped adjustment groove. The positioning sensor is installed in the waist-shaped adjustment groove by fasteners and can move along the length direction of the waist-shaped adjustment groove to adjust the swing angle of the swing arm corresponding to the cleaning start position, so as to adapt to polishing discs of different diameters.

[0012] Furthermore, the high-pressure nozzle array consists of multiple nozzles arranged in a specific direction along the end of the swing arm, and the nozzles are configured to convert the cleaning medium into a fan-shaped jet or atomized flow that covers a radial strip area of ​​the polishing pad.

[0013] Furthermore, the nozzle has a spray pressure of 0.5 MPa to 3.0 MPa and a spray angle of 30° to 60°, forming a fan-shaped water curtain that covers the entire effective area of ​​the polishing disc.

[0014] Furthermore, the dual-mode fluid supply system also includes an auxiliary pure water flow path, which is activated in the cleaning operation mode to supply pure water to the surface of the polishing pad for pre-wetting or auxiliary cleaning.

[0015] Furthermore, the control system is also configured to adjust the pressure of the cleaning medium supplied to the cleaning flow path in order to precisely control the impact force of the fluid ejected from the high-pressure nozzle array on the surface of the polishing pad.

[0016] Secondly, the present invention provides a chemical mechanical polishing device, characterized in that it integrates a cleaning-liquid supply integrated device as described above, for performing online deep cleaning of the focusing pad without interrupting the process flow.

[0017] Third, the present invention also provides an online cleaning method for polyurethane polishing pads, employing the cleaning-liquid supply integrated device as described above, characterized by comprising the following steps: S1. After polishing is completed, the control system drives the swing arm to move radially towards the center along the polishing disk; S2. The position sensor assembly monitors the position of the swing arm and outputs a trigger signal when it detects that the arm has reached the cleaning start position aligned with the center of the polishing disc. S3. The control system responds to the trigger signal and starts the high-pressure pump, so that pure water is sprayed in atomized jet along the diameter direction through the high-pressure nozzle array; S4. Simultaneously control the polishing disc to rotate at a low speed, and use centrifugal force to assist the water flow to penetrate the polyurethane micropores to complete deep cleaning; S5. After cleaning, turn off the high-pressure pump, reset the swing arm, and prepare for the next round of polishing.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) By using controllable high-pressure fluid instead of physical brushing, the jet can penetrate and clean the internal cavities and deep pores of the polyurethane polishing pad, solving the industry problem of "deep residue", improving the cleanliness of the polishing pad, and providing a stable and clean interface for subsequent polishing processes, which is conducive to improving product yield and process consistency.

[0019] 2) Through the dynamic cleaning mode of rotating disc and fixed spray, high-pressure fluid can cover the entire surface of the polishing pad, eliminating the static or dynamic cleaning dead corners caused by the shape and movement of the brush body in traditional brushing.

[0020] 3) The entire cleaning process is a non-contact interaction between the fluid and the pad surface, which completely avoids physical damage such as scratching and pulling of the microstructure of the soft polyurethane pad surface by hard objects such as brush bristles, perfectly meeting the core premise of "not damaging the pad surface" and effectively extending the service life of expensive polishing pads.

[0021] 4) Integrating the liquid supply and cleaning functions into one unit reduces the equipment's footprint and the number of external components. Inside the CMP equipment, there is no need for mechanical switching or workpiece stage movement between the liquid supply arm and cleaning arm, significantly shortening the transition time between polishing and cleaning processes and increasing the overall throughput (UPH) of the equipment. 5) Through the closed-loop control of the positioning sensor and the host computer, the entire process from liquid supply to cleaning mode switching, precise positioning and automatic cleaning is automated, reducing manual intervention and improving the reliability and repeatability of the process. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the invention for an integrated cleaning and liquid supply device for polyurethane polishing pads. Figure 2 This is a schematic diagram of the positioning sensor in this invention; Figure 3 This is a diagram showing the usage status of the integrated cleaning and liquid supply device for polyurethane polishing pads according to the present invention. In the diagram: 1 Base; 2 Rotary seat; 3 Swing arm; 4 High-pressure nozzle array; 5 Position sensor assembly; 5-1 Position sensor mounting base; 5-2 Position sensor; 5-3 Side set screw; 6 Dual-mode fluid supply system; 6-1 Liquid supply path; 6-2 Auxiliary pure water path; 6-3 Cleaning path. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Those skilled in the art can make appropriate adjustments or modifications to the implementation details based on the following description without departing from the principles and spirit of the present invention, and such adjustments or modifications should be considered to fall within the protection scope of the present invention.

[0024] like Figure 1 As shown, the present invention provides an integrated cleaning-liquid supply device for polyurethane polishing pads, comprising: a base 1, a rotating base 2, a swing arm 3, a high-pressure nozzle array 4, and a positioning sensor assembly 5.

[0025] The base 1 is fixed on the CMP equipment frame and has a hollow channel inside for laying liquid pipelines and sensor lines.

[0026] Rotary base 2: Rotatably mounted on base 1 via bearings or other mechanisms. Rotary base 2 also has a hollow channel inside, communicating with the channel in base 1. The rotation is driven by a servo motor or stepper motor and controlled by a host computer.

[0027] Swing arm 3: Connected to the front end of rotating base 2 via a pivot, it can swing relative to rotating base 2 in a plane under the action of a drive device (such as another motor). The swing arm 3 has independent liquid supply flow path and cleaning flow path isolated by switching valve, as well as optional air passage.

[0028] The high-pressure nozzle array 4 is fixedly installed at the end of the swing arm 3 away from the rotating seat 2. The high-pressure nozzle array 4 consists of multiple high-pressure nozzles arranged at a specific spacing and angle, used to atomize the cleaning medium (such as pure water) or form a fan-shaped jet to cover an area of ​​a specific width in cleaning mode.

[0029] Position sensor assembly 5: used to detect whether the swing arm 3 has moved to the preset cleaning start position.

[0030] Example: When the CMP equipment requires wafer polishing, this device switches to liquid supply mode, and its workflow is as follows: ①Preparation and positioning: The host computer controls the movement of the rotating seat 2 and the swing arm 3 to position the liquid supply outlet at the end of the swing arm 3 to the designated liquid supply area above the polishing disc.

[0031] ② Liquid supply: The host computer issues a liquid supply command to control the polishing liquid pump to start; The polishing slurry passes through the base 1, the rotating seat 2 and the internal channels of the swing arm 3 in sequence via the liquid supply path, and finally drips evenly from the liquid supply outlet at the end of the swing arm onto the surface of the rotating polyurethane polishing pad. During the polishing process, the host computer can adjust the flow rate of the polishing slurry as needed to ensure process stability. After the slurry supply is completed, the polishing slurry control valve and pump are turned off.

[0032] When the polishing process is complete and the polyurethane polishing pad needs to be cleaned, switch to the cleaning mode. The workflow is as follows: ①The host computer controls the drive mechanism to move the swing arm 3 towards the center along the radius of the polishing disc; ② Position detection: Position sensor component 5 detects position in real time. For example... Figure 2 As shown, the assembly includes a sensor mounting base 5-1 and a positioning sensor body 5-2. The sensor mounting base 5-1 is fixed to the rotating base 2 by screws and has a slotted groove. The positioning sensor 5-2 is mounted in the slotted groove of the mounting base 5-1 by a side set screw 5-3. The mounting angle of the positioning sensor 5-2 can be finely adjusted along the slot by loosening the set screw 5-3, thereby calibrating or setting different trigger positions to adapt to different equipment or process requirements. A detection point (such as a reflector, magnet, or physical bump) corresponding to the positioning sensor 5-2 is provided on the base 1. When the swing arm 3 swings until its axis aligns with the center of the polishing disc (the preset cleaning start position), the positioning sensor 5-2 is precisely aligned with the detection point on the base 1.

[0033] The positioning sensor 5-2 detects the signal and transmits it to the host computer.

[0034] After receiving the signal, the host computer immediately stops the motor driving the swing arm 3 to swing, causing the swing arm 3 to stop and lock at the preset "centripetal position". At this time, the high-pressure nozzle array 4 installed at the end of the swing arm 3 is precisely aligned with the radial starting cleaning line of the polishing disc.

[0035] ③ High-pressure cleaning: After the position is locked, the host computer will synchronously perform the following operations: a) Open the control ball valve of auxiliary pure water flow path 6-2 in the liquid supply system, start the pure water pump, and deliver pure water to the end of the swing arm through a path similar to the liquid supply mode to initially wet the pad surface and assist in subsequent high-pressure cleaning.

[0036] b) Start the dedicated cleaning pipeline high-pressure pump to pump high-pressure pure water (the pressure can be adjusted within the range of 10-100 bar according to the process) into the independent cleaning pipeline. This pipeline also passes through the base 1 and the rotating seat 2, and finally connects to the high-pressure channel in the swing arm 3, directly reaching the high-pressure nozzle array 4.

[0037] ④ Dynamic blind-spot-free rinsing: High-pressure pure water is atomized into high-speed microdroplets or forms a dense fan-shaped jet through the high-pressure nozzle array 4, covering a radial strip area of ​​the polishing pad at a certain incident angle.

[0038] At the same time, the host computer controls the spindle motor of the CMP equipment to drive the polishing disc to start rotating at low or medium speed.

[0039] During the rotation of the polishing disc, high-pressure fluid ejected from the fixed-position high-pressure nozzle array 4 sequentially washes the entire circumferential surface of the polishing disc. By controlling the number of rotations of the polishing disc (e.g., 1-3 rotations), it can be ensured that the entire disc surface, including the micropores and internal cavity gaps of the polyurethane material surface, is subjected to penetrating impact and scouring by the high-pressure fluid, thoroughly removing residual polishing liquid and waste.

[0040] ⑤ Cleaning End Reset: After the preset cleaning time or number of rotations is completed, the host computer sequentially shuts off the water pump and related valves. Then, it controls the swing arm 3 to swing back to the standby position, waiting for the next work cycle.

[0041] This invention integrates liquid supply and high-pressure cleaning functions through the above-described embodiments, and utilizes mechanical motion and sensor positioning to achieve efficient, thorough, and non-destructive automated maintenance of polyurethane polishing pads. Those skilled in the art can adapt the specific dimensions of components, motor models, sensor types, pipe diameters, and pressure values ​​according to the actual equipment dimensions and process parameters, without departing from the spirit and scope of this invention.

Claims

1. An integrated cleaning-liquid supply device for polyurethane polishing pads, characterized in that, include: The base (1) is used to fix the equipment on the frame of the chemical mechanical polishing equipment and has a hollow channel inside; A rotating seat (2) is rotatably mounted on the base (1) and has a hollow channel inside; The swing arm (3) is connected to the rotating seat (2) at one end and can swing along the radial direction of the polishing disc. The other end is provided with a high-pressure nozzle array (4). The dual-mode fluid supply system includes an independent liquid supply path and a cleaning path, both of which are installed in the hollow channels of the base, the rotating seat and the swing arm. The liquid supply path has a liquid supply outlet at the end for supplying polishing liquid to the polishing pad. The cleaning path is connected to the high-pressure nozzle array (4) at the end for supplying high-pressure cleaning medium to the high-pressure nozzle array (4). A position sensor assembly (5) is disposed on the rotating seat (2) for detecting whether the swing arm (3) swings to a preset cleaning start position; as well as The control system is communicatively connected to the dual-mode fluid supply system, the positioning sensor assembly (5), and the drive mechanism that drives the rotating seat (2) and the swing arm (3), and is configured as follows: In the polishing operation mode, the liquid supply path is opened and polishing liquid is supplied to the polishing pad through the swing arm (3); In the cleaning operation mode, the swing arm (3) is controlled to swing towards the center of the polishing pad, and based on the detection signal of the positioning sensor assembly (5), the swing arm (3) is controlled to stop at the cleaning start position; then, the cleaning flow path is opened, so that the high-pressure cleaning medium is sprayed out through the high-pressure nozzle array (4), and the polishing pad is controlled to rotate, so that the fixed spray of the high-pressure nozzle array (4) and the rotational motion of the polishing pad are combined to achieve dynamic, non-contact high-pressure rinsing of the entire polishing pad surface.

2. The integrated cleaning-liquid supply device for polyurethane polishing pads according to claim 1, characterized in that, The positioning sensor assembly (5) includes: A sensor mounting base (5-1) is fixed to the side wall of the rotating base (2); a positioning sensor (5-2) is mounted on the sensor mounting base (5-1); and A corresponding triggering component is disposed on the base (1); The detection end of the positioning sensor (5-2) is positioned towards the triggering component. When the swing arm (3) swings to the cleaning start position, the positioning sensor (5-2) is opposite to the triggering component and generates a positioning signal.

3. The integrated cleaning-liquid supply device for polyurethane polishing pads according to claim 2, characterized in that, The sensor mounting base (5-1) has a waist-shaped adjustment groove. The positioning sensor (5-2) is installed in the waist-shaped adjustment groove by fasteners and can move along the length of the waist-shaped adjustment groove to adjust the swing angle of the swing arm corresponding to the cleaning start position, so as to adapt to polishing discs of different diameters.

4. The integrated cleaning-liquid supply device for polyurethane polishing pads according to claim 1, characterized in that, The high-pressure nozzle array (4) consists of a plurality of nozzles arranged in a specific direction along the end of the swing arm (3), the nozzles being configured to convert the cleaning medium into a fan-shaped jet or atomized flow covering a radial strip area of ​​the polishing pad.

5. The integrated cleaning-liquid supply device for polyurethane polishing pads according to claim 4, characterized in that, The nozzle has a spray pressure of 0.5 MPa to 3.0 MPa and a spray angle of 30° to 60°, forming a fan-shaped water curtain that covers the entire effective area of ​​the polishing disc.

6. The integrated cleaning-liquid supply device for polyurethane polishing pads according to claim 1, characterized in that, The dual-mode fluid supply system also includes an auxiliary pure water flow path, which is activated in the cleaning operation mode to supply pure water to the surface of the polishing pad for pre-wetting or auxiliary cleaning.

7. The integrated cleaning-liquid supply device for polyurethane polishing pads according to claim 1, characterized in that, The control system is also configured to adjust the pressure of the cleaning medium supplied to the cleaning flow path in order to precisely control the impact force of the fluid ejected by the high-pressure nozzle array (4) on the surface of the polishing pad.

8. A chemical mechanical polishing apparatus, characterized in that, The device integrates a cleaning-liquid supply unit as described in any one of claims 1 to 7, for performing online deep cleaning of the focusing pad without interrupting the process flow.

9. An online cleaning method for polyurethane polishing pads, employing the integrated cleaning-liquid supply device as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1. After polishing is completed, the control system drives the swing arm (3) to move radially toward the center along the polishing disk; S2. The position sensor assembly (5) monitors the position of the swing arm and outputs a trigger signal when it detects that the arm has reached the cleaning start position aligned with the center of the polishing disc. S3. The control system responds to the trigger signal and starts the high-pressure pump, so that pure water is sprayed in atomized jet along the diameter direction through the high-pressure nozzle array (4); S4. Simultaneously control the polishing disc to rotate at a low speed, and use centrifugal force to assist the water flow to penetrate the polyurethane micropores to complete deep cleaning; S5. After cleaning, turn off the high-pressure pump, reset the swing arm (3), and prepare for the next round of polishing.

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