Polishing pad cleaning device and cleaning method

Abstract

The invention discloses a polishing pad cleaning device and method, and the polishing pad cleaning device comprises a cleaning arm which is provided with a plurality of nozzles; the flow guide barriers can guide waste liquid on the polishing pad to the circle center direction of the polishing pad so that the liquid level of the waste liquid in the center area of the polishing pad can be increased, a slurry outlet of the grinding slurry arm extends to the center area, the waste liquid in the center area is gathered into a cleaning area, and the slurry outlet of the grinding slurry arm can be cleaned; and the vacuum suction nozzle is connected with the vacuum flow channel and is used for providing negative pressure suction force and sucking away the waste liquid. According to the polishing pad cleaning device provided by the invention, by arranging the polishing pad cleaning device with the cleaning arm, the flow guide barrier and the vacuum suction nozzle, waste liquid is guided to the central area of the polishing pad to be gathered into a cleaning area, so that the cleaning efficiency and the cleaning effect of the central area are improved, and meanwhile, cleaning of a slurry outlet corresponding to a slurry grinding arm is completed; and the wafer is prevented from being scratched due to crystal formed at the slurry outlet.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer manufacturing, and in particular to a polishing pad cleaning device and a cleaning method. Background Art

[0002] In the field of semiconductor manufacturing, the polishing process is one of the key steps to achieve wafer surface flatness. As the core component in the polishing process, the surface condition of the polishing pad directly affects the polishing quality. As the polishing process progresses, polishing liquid, abrasive particles, wafer materials and other residues will gradually accumulate on the surface of the polishing pad. If these residues are not removed in time, they will lead to problems such as uneven polishing and wafer surface defects, which will seriously affect the product yield.

[0003] Existing polishing pad cleaning technologies mainly rely on physical or chemical methods to remove residues. Physical methods generally include centrifugal cleaning and high-pressure water washing. Centrifugal cleaning uses the centrifugal force generated by high-speed rotation to throw the waste liquid off the surface of the polishing pad, but this method has certain limitations: under the action of centrifugal force, the tiny particles in the waste liquid may not be completely separated from the polishing pad, but remain on the surface or in the micropores, especially in the central area of ​​the polishing pad. The waste liquid is subjected to less centrifugal force, and during the throwing-out process, the speed is lower, which makes it easier for tiny particles to be retained in the central area of ​​the polishing pad and fail to achieve a good cleaning effect. The equipment structure of high-pressure water washing is as follows: Figure 1 As shown, when the polishing pad 1 needs to be rinsed with high-pressure water, the dresser 2 swings to the outside of the polishing pad 1, the polishing head 5 does not contact the polishing pad 1, and the cleaning component 3 sprays high-pressure water to the polishing pad 1 while the polishing pad 1 rotates. Although the high-pressure water rinse can further remove the residue, the high-pressure water flow may cause waste liquid to splash, especially when there are crystals on the surface of the polishing pad 1. The splashing waste liquid may bring the crystals to the grinding slurry arm 4, forming a new pollution source. In the subsequent polishing process, once these crystals fall, they will cause scratches on the wafer, which will greatly reduce the product yield of the wafer.

[0004] The chemical method uses specific chemical cleaning agents to dissolve or soften the residues, but the use of chemical cleaning agents may corrode the polishing pad material, affecting its service life, and may also cause environmental pollution and operational safety issues.

[0005] Therefore, there are some urgent problems to be solved in the prior art during the polishing pad cleaning process, especially in terms of waste liquid treatment and crystallization control. How to effectively remove tiny particles on the surface of the polishing pad while preventing waste liquid from splashing onto the grinding slurry arm to form crystals has become a key technical problem in improving the cleaning efficiency of the polishing pad and the quality of wafer processing. Summary of the invention

[0006] The present invention aims to provide a new type of polishing pad cleaning device and cleaning method, which solves the above-mentioned technical problems through innovative design and process flow, realizes efficient cleaning of the polishing pad, reduces defects in the wafer processing process, and improves the yield and reliability of semiconductor products.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A polishing pad cleaning device, comprising: A cleaning arm, wherein a plurality of nozzles are provided on the cleaning arm; At least one guide barrier, the guide barrier can guide the waste liquid on the polishing pad toward the center of the polishing pad so as to raise the waste liquid level in the central area of ​​the polishing pad, the slurry outlet of the grinding slurry arm extends to the central area, the waste liquid in the central area gathers into a cleaning area, and the slurry outlet of the grinding slurry arm can be cleaned; A vacuum suction nozzle is connected to a vacuum flow channel and is used to provide negative pressure suction to suck away the waste liquid. The vacuum suction nozzle can be arranged on the cleaning arm or can be arranged as a liquid suction pipeline independent of the cleaning arm.

[0008] By setting up a diversion barrier, the waste liquid is gathered to the central area of ​​the polishing pad to form a cleaning area, thereby further improving the cleaning effect of the central area of ​​the polishing pad. At the same time, the slurry outlet of the grinding slurry arm is covered and cleaned synchronously, thereby avoiding contamination of the grinding slurry arm.

[0009] Preferably, the diversion barrier is a liquid barrier formed by liquids sprayed from a plurality of the nozzles. The advantage of providing a liquid barrier is that the action of the nozzle spraying the flushing liquid can simultaneously play two roles, one is to flush the polishing pad, the other is to divert the waste liquid, and the flushing effect and the diversion effect can be adjusted by adjusting the pressure of the liquid supply.

[0010] Preferably, the spraying surfaces of two adjacent nozzles partially overlap. With this arrangement, the formed liquid barrier can be continuous. When the spraying angle is fixed, the larger the area of ​​the overlapping part, the higher the height of the liquid barrier. For example, when the spraying angle is 90 degrees, the center of the nozzle sprays vertically downward, and the edge of the spraying surface of one nozzle can cover the area directly below the adjacent nozzle, the height of the formed liquid barrier is greater than half of the distance from the nozzle to the upper surface of the polishing pad.

[0011] Preferably, the spray direction of at least one of the nozzles is set to be towards the center of the polishing pad. Such a setting can further improve the diversion effect of the diversion barrier and make it easier for the waste liquid to gather in the central area of ​​the polishing pad.

[0012] Preferably, the spray directions of the nozzles are all set to be toward the center of the polishing pad. Such a setting can further increase the height of the liquid barrier. When the inclination angle of the nozzle reaches a certain degree, the height of the liquid barrier can reach the height of the nozzle outlet. It can also further increase the liquid impact force on the waste liquid in the direction toward the center of the polishing pad, so that the waste liquid can gather to the central area of ​​the polishing pad more quickly.

[0013] Preferably, the spraying direction of the nozzle is opposite to the rotation direction of the polishing pad, so that a greater relative speed can be generated between the cleaning liquid and the polishing pad, thereby further improving the flushing effect on the polishing pad.

[0014] Preferably, the cleaning arm is provided with a boosting nozzle facing the center of the polishing pad near the center of the polishing pad. By providing the boosting nozzle, the cleaning effect of the central area of ​​the polishing pad can be further improved.

[0015] Preferably, the spray direction of the boosting nozzle is the same as the rotation direction of the polishing pad, which increases the rotational velocity of the liquid in the cleaning area and is more conducive to cleaning the central area of ​​the polishing pad and the grinding slurry arm; the boosting nozzle cooperates with the nozzle closest to the central area, and the two nozzles work together to enhance the cleaning force of the central area of ​​the polishing pad, improve the cleaning efficiency, and improve the cleaning effect.

[0016] Preferably, the diversion barrier is a solid baffle. By setting the solid baffle, the diversion barrier can completely block the waste liquid from below the cleaning arm to the upper surface close to the polishing pad and guide it toward the center of the polishing pad, thereby achieving a better diversion effect.

[0017] Preferably, the guide barrier is a double guide barrier structure consisting of a liquid barrier formed by liquids sprayed from a plurality of nozzles and a solid baffle. By setting up the double guide barrier structure, a better guide effect can be achieved.

[0018] Preferably, the opening of the vacuum nozzle is arranged in the central area of ​​the polishing pad. Such a setting can suck away the waste liquid in the central area of ​​the polishing pad, avoid the retention of tiny particles in the central area of ​​the polishing pad, and further increase the flow rate of the waste liquid flowing to the central area of ​​the polishing pad, thereby enhancing the cleaning effect.

[0019] Preferably, the opening of the vacuum suction nozzle is arranged in the central area of ​​the polishing pad and the extended area of ​​the central area, and can be as large as the outer circular boundary of the polishing pad. Such an arrangement makes the vacuum suction nozzle closer to the nozzle, and the waste liquid after flushing can be sucked away more promptly, thereby enhancing the cleaning effect.

[0020] Preferably, the vacuum flow channel is connected to a filter, a filter element is provided in the filter, the filter is connected to a vacuum generator, and one end of the vacuum generator is connected to an air source. By providing an air source and a vacuum generator, an air source flow channel is formed to generate a vacuum negative pressure and connect the vacuum flow channel, and the filter element in the filter is used to filter the sucked out waste liquid, and the filter element is cleaned regularly to avoid waste liquid from polluting the environment.

[0021] A polishing pad cleaning method of the polishing pad cleaning device according to any one of the above items comprises the following steps: S1: Start the rotation of the polishing pad, open the nozzle on the cleaning arm, and make the nozzle spray the cleaning liquid toward the polishing pad; S2: The cleaning liquid rotates with the polishing pad and gathers toward the center of the polishing pad under the action of the guide barrier, and the liquid level rises to form a cleaning area; S3: Open the vacuum nozzle and use negative pressure to suck away the waste liquid.

[0022] By rotating the polishing pad and opening the nozzle to spray cleaning liquid, the cleaning liquid rotates with the polishing pad and gathers to the central area of ​​the polishing pad under the action of the diversion barrier. The liquid level rises to form a cleaning area, and then the negative pressure of the vacuum nozzle is used to suck away the waste liquid, which solves the problem that the waste liquid in the central area of ​​the polishing pad is subjected to less centrifugal force and a lower throwing speed, which makes it easier for tiny particles to be retained and fail to achieve a good cleaning effect. At the same time, the cleaning area formed by the rising liquid level can realize the synchronous cleaning of the grinding slurry arm, avoiding contamination of the grinding slurry arm.

[0023] Preferably, step S3 comprises the following steps: S31: the flow rate of the waste liquid sucked away by the vacuum nozzle is set to be smaller than the flow rate of the cleaning liquid sprayed through the nozzle, the cleaning area is gradually expanded, and part of the waste liquid cannot be sucked away by the vacuum nozzle in time and flows out at the circumference of the polishing pad, and this state is maintained for cleaning until a preset time; S32: Close the nozzle and use the vacuum nozzle to suck away the waste liquid.

[0024] By maintaining the cleaning for a period of time, the polishing pad and the slurry arm are cleaned more thoroughly.

[0025] Preferably, the cleaning arm is provided with a booster nozzle facing the center of the polishing pad near the center of the polishing pad, and in step S1, the nozzle on the cleaning arm and the booster nozzle are opened at the same time. The two nozzles work together to strengthen the cleaning force of the central area of ​​the polishing pad, thereby improving the cleaning efficiency and the cleaning effect of the central area.

[0026] Compared with the prior art, the present invention has the following beneficial effects: The present invention proposes a polishing pad cleaning device. By arranging a polishing pad cleaning device with a cleaning arm, a diversion barrier and a vacuum suction nozzle, the waste liquid on the polishing pad can be diverted toward the center of the polishing pad, so that the waste liquid is gathered in the central area of ​​the polishing pad to form a cleaning area. By arranging a booster nozzle to coordinate with the nozzle closest to the central area, the two nozzles work together to enhance the cleaning force of the central area, improve the cleaning efficiency and the cleaning effect of the central area, and at the same time complete the cleaning of the grinding slurry arm, avoid the formation of new crystals on the grinding slurry arm, and ensure the polishing quality of subsequent wafer products.

[0027] The present invention proposes a polishing pad cleaning method. By applying the polishing pad cleaning device provided by the present invention, the polishing pad is first rinsed with a booster nozzle and a nozzle, and then the waste liquid is sucked away with negative pressure to efficiently clean the surface of the polishing pad. A large amount of pollutants are first rinsed to remove, and then negative pressure adsorption is performed. The combination of the two quickly removes pollutants on the polishing pad to ensure the cleaning effect and efficiency, and realizes efficient cleaning of the polishing pad, especially the cleaning of the central area of ​​the polishing pad is more thorough, reducing the retention of tiny particles, and using the cleaning area formed by the guide barrier to synchronously clean the grinding slurry arm, avoiding the contamination of the grinding slurry arm, reducing defects in the wafer processing process, and improving the yield and reliability of semiconductor products. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a structural schematic diagram of the prior art of the present invention; Figure 2 A schematic diagram of the structure of the polishing pad cleaning device provided by the present invention; Figure 3 A schematic diagram of the structure of the polishing pad cleaning device provided by the present invention from a side and rear perspective; Figure 4 A structural schematic diagram of the polishing pad cleaning device provided by the present invention from another side perspective; Figure 5 A schematic diagram of the working principle of the polishing pad cleaning device provided by the present invention; Figure 6 A schematic diagram of the structure of the polishing pad cleaning device provided by the present invention in a cleaning working state; Figure 7 A schematic diagram of the structure of the nozzle spacing arrangement of the polishing pad cleaning device provided by the present invention; Figure 8A schematic diagram of the shape of a guide barrier formed when the nozzles of the polishing pad cleaning device provided by the present invention are arranged at intervals; Fig. 9 A schematic diagram of the structure of the polishing pad cleaning device provided by the present invention when a nozzle close to the outermost side of the circumference of the polishing pad is set to be inclined toward the center of the circle; Fig.10 A schematic diagram of the structure of the polishing pad cleaning device provided by the present invention when all nozzles are set to be inclined toward the center of the circle and a schematic diagram of the shape of the resulting guide barrier; Fig.11 A schematic diagram of the structure of the polishing pad cleaning device provided by the present invention when the spray direction of the nozzle is set to be opposite to the rotation direction of the polishing pad; Fig.12 A schematic diagram of the installation position and orientation of the power-assisting nozzle of the polishing pad cleaning device provided by the present invention Figure 1 ; Fig.13 A schematic diagram of the installation position and orientation of the power-assisting nozzle of the polishing pad cleaning device provided by the present invention Figure 2 ; Fig.14 A schematic diagram of the cleaning flow direction of the power-assisted nozzle of the polishing pad cleaning device provided by the present invention; Fig.15 A schematic diagram of the structure of a physical baffle of the polishing pad cleaning device provided by the present invention; Fig.16 A cross-sectional view of the working state of the vacuum flow channel of the polishing pad cleaning device provided by the present invention; Fig.17 This is a cross-sectional view of the working status of the vacuum flow channel and the gas source flow channel of the polishing pad cleaning device provided by the present invention.

[0030] Description of reference numerals: Polishing pad; 11. polishing pad center; Finisher; Cleaning assembly; 30, cleaning arm; 31, nozzle; 311, power nozzle; 312, power nozzle cleaning flow direction; 313, solid baffle; 32, vacuum nozzle; 33, filter; 34, air source; 35, vacuum generator; 36, liquid supply device; 37, vacuum flow channel; 38, filter element; 39, air source flow channel; grinding slurry arm; Polishing head; The flow trajectory of waste liquid in the center area of ​​the polishing pad; diversion barriers; Power-assisted nozzle flushing line; Waste liquid. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] like Figures 2 to 5 , Figure 6 , Fig.12 and Fig.16 As shown, a polishing pad cleaning device comprises: A cleaning arm 30, on which a plurality of nozzles 31 are provided; At least one guide barrier 7, the guide barrier 7 can guide the waste liquid 9 on the polishing pad 1 to the center 11 of the polishing pad, so that the liquid level of the waste liquid 9 in the central area of ​​the polishing pad 1 is raised, the slurry outlet of the grinding slurry arm 4 extends to the central area, and the waste liquid 9 in the central area is gathered into a cleaning area, which can clean the slurry outlet of the grinding slurry arm 4; like Figure 5 As shown, the waste liquid 9 flowing on the surface of the polishing pad 1 is blocked by the guide barrier 7 and guided to the central area, so as to form a waste liquid flow trajectory line 6 in the central area of ​​the polishing pad. In the figure, W is the rotation direction of the polishing pad 1; Vacuum suction nozzle 32, vacuum suction nozzle 32 is connected to vacuum flow channel 37 ( Fig.16 As shown), it is used to provide negative pressure suction to suck away the waste liquid 9; the vacuum suction nozzle 32 can be set on the cleaning arm 30, or it can be set as a suction pipeline independent of the cleaning arm 30, so as to utilize the adsorption force provided by the vacuum nozzle 32 to discharge the waste liquid through the vacuum channel 37 to the outside of the polishing pad 1.

[0033] like Figure 5 , Figure 6 and Fig.12 As shown, by setting up the diversion barrier 7, the waste liquid 9 is gathered to the central area of ​​the polishing pad 1 to form a cleaning area, thereby further improving the cleaning effect of the central area of ​​the polishing pad 1. At the same time, the slurry outlet of the grinding slurry arm 4 is covered and cleaned synchronously, thereby avoiding contamination of the grinding slurry arm 4.

[0034] like Figure 6 As shown, in some embodiments, the diversion barrier 7 is a liquid barrier formed by the liquid sprayed by a plurality of the nozzles 31. The advantage of providing the liquid barrier is that the action of the nozzle 31 spraying the flushing liquid can simultaneously play two roles, one is to flush the polishing pad 1, and the other is to divert the waste liquid 9. Moreover, the flushing effect and the diversion effect can be adjusted by adjusting the pressure of the liquid supply.

[0035] like Figure 7 and Figure 8As shown, in some embodiments, the ejection surfaces of two adjacent nozzles 31 partially overlap. With this arrangement, the formed liquid barrier can be continuous. When the ejection angle is fixed, the larger the area of ​​the overlapping portion, the higher the height of the liquid barrier. For example, when the ejection angle is 90 degrees, the center of the nozzle ejects vertically downward, and the edge of the ejection surface of one nozzle 31 can cover the area directly below the adjacent nozzle 31, the height of the formed liquid barrier is greater than half of the distance between the nozzle 31 and the upper surface of the polishing pad 1. Figure 8 The dashed line at the highest point of the shaded area is the height of the liquid barrier.

[0036] like Fig. 9 As shown, in some embodiments, the spray direction of at least one nozzle 31 among the nozzles 31 is set to be toward the center 11 of the polishing pad. Such a setting can further improve the diversion effect of the diversion barrier 7, so that the waste liquid 9 is impacted by the liquid in the direction toward the center 11 of the polishing pad, and is more likely to gather in the central area of ​​the polishing pad 1.

[0037] like Fig.10 As shown, in some embodiments, the spray direction of the nozzle 31 is all set to be toward the center 11 of the polishing pad. Such a setting can further increase the height of the liquid barrier. When the inclination angle of the nozzle 31 reaches a certain level, the height of the liquid barrier can reach the height of the outlet of the nozzle 31. The dotted line at the highest point of the shaded part in the figure is the height of the liquid barrier; it can also further increase the liquid impact force on the waste liquid 9 in the direction toward the center 11 of the polishing pad, so that the waste liquid 9 can gather to the central area of ​​the polishing pad 1 more quickly.

[0038] like Fig.11 As shown, in some embodiments, the spraying direction of the nozzle 31 is opposite to the rotation direction of the polishing pad 1, so that a greater relative speed can be generated between the cleaning liquid and the polishing pad 1, further improving the flushing effect of the polishing pad 1. Specifically, the fluid sprayed by the nozzle 31 obliquely impacts the particles on the surface of the polishing pad 1, thereby increasing the lateral force on the particles, so that the particles can be peeled off from the surface of the polishing pad 1.

[0039] Fig.11 The projection of the conical surface formed by the fluid jet from the nozzle 31 on the vertical plane is shown, wherein the angle between the side of the conical surface formed by the fluid jet and the horizontal plane (the plane where the polishing pad is located) is 75°-90°, so that the fluid jet can be sprayed as vertically as possible to the groove on the surface of the polishing pad to improve the cleaning effect of the nozzle 31. Preferably, the angle between the side of the conical surface formed by the fluid jet and the plane where the polishing pad is located is 85°-90°, so as to flush the particles remaining on the sidewall and bottom of the groove of the polishing pad, and the particles are separated from the groove of the polishing pad and scattered on the surface of the polishing pad, so as to be thrown off to the outside of the polishing pad under the action of centrifugal force. Fig.12As shown, in some embodiments, the cleaning arm 30 is provided with a boosting nozzle 311 facing the center 11 of the polishing pad near the center 11 of the polishing pad. By providing the boosting nozzle 311, the cleaning effect of the central area of ​​the polishing pad 1 can be further improved.

[0040] Fig.13 and Fig.14 As shown, in some embodiments, the spray direction of the boosting nozzle 311 is the same as the rotation direction of the polishing pad 1, which increases the rotational velocity of the liquid in the cleaning area, and is more conducive to cleaning the central area of ​​the polishing pad 1 and the grinding slurry arm 4; the boosting nozzle 311 cooperates with the nozzle 31 closest to the central area, and the two nozzles work together to strengthen the cleaning force of the central area of ​​the polishing pad 1, improve the cleaning efficiency, and improve the cleaning effect. Fig.14 In FIG. 3 , the arrow indicates the cleaning flow direction 312 of the boost nozzle. When the spraying direction of the boost nozzle 311 is the same as the rotation direction of the polishing pad 1, the position of the boost nozzle flushing line 8 is as follows: Figure 5 As shown, W is the rotation direction of the polishing pad 1, and v is the speed direction of the boosting nozzle spraying the liquid.

[0041] like Fig.15 As shown, in some embodiments, the diversion barrier 7 is a solid baffle 313. By setting the solid baffle 313, the diversion barrier 7 can completely block the waste liquid 9 from the bottom of the cleaning arm 30 to the upper surface close to the polishing pad 1 and guide it toward the center 11 of the polishing pad, thereby achieving a better diversion effect.

[0042] In some embodiments, the guide barrier 7 is a double guide barrier structure composed of a liquid barrier formed by liquid sprayed from a plurality of nozzles 31 and a solid baffle 313. By setting up the double guide barrier structure, a better guide effect can be achieved.

[0043] like Fig.16 As shown, in some embodiments, the opening of the vacuum nozzle 32 is set in the central area of ​​the polishing pad 1. With this setting, the waste liquid 9 in the central area of ​​the polishing pad 1 can be sucked away to avoid the retention of tiny particles in the central area of ​​the polishing pad 1; at the same time, the vacuum nozzle 32 directs the waste liquid 9 in the central area of ​​the polishing pad 1 to the nozzle port, thereby increasing the flow rate of the waste liquid 9 on the surface of the polishing pad 1 and enhancing the cleaning effect of the surface of the polishing pad 1.

[0044] In some embodiments, the opening of the vacuum nozzle 32 is set in the central area of ​​the polishing pad 1 and the extended area of ​​the central area, and can reach the outer circular boundary of the polishing pad 1 at most. This setting makes the vacuum nozzle 32 closer to the nozzle 31, and the waste liquid 9 after flushing can be sucked away more promptly, thereby enhancing the cleaning effect.

[0045] like Fig.17As shown, in some embodiments, the vacuum channel 37 is connected to the filter 33, a filter element 38 is provided in the filter 33, the filter 33 is connected to the vacuum generator 35, and one end of the vacuum generator 35 is connected to the gas source 34. By providing the gas source 34 and the vacuum generator 35, a gas source channel 39 is formed to generate a vacuum negative pressure and connect the vacuum channel 37, and the filter element 38 in the filter 33 is used to filter the sucked waste liquid 9, and the filter element 38 is cleaned regularly to avoid the waste liquid 9 from polluting the environment.

[0046] A polishing pad cleaning method according to any one of the above polishing pad cleaning devices comprises the following steps: S1: Start the rotation of the polishing pad 1, open the nozzle 31 on the cleaning arm 30, and make the nozzle 31 spray the cleaning liquid toward the polishing pad 1; S2: The cleaning liquid rotates with the polishing pad 1 and gathers toward the central area of ​​the polishing pad 1 under the action of the guide barrier 7, and the liquid level rises to form a cleaning area; S3: Open the vacuum suction nozzle 32 and use negative pressure to suck away the waste liquid 9.

[0047] The nozzle 31 is opened and the cleaning liquid is sprayed toward the rotating polishing pad 1, so that the cleaning liquid rotates with the polishing pad 1 and gathers toward the central area of ​​the polishing pad 1 under the action of the guide barrier 7, the liquid level rises to form a cleaning area, and then the negative pressure of the vacuum suction nozzle 32 is used to suck away the waste liquid 9, thereby solving the problem that the waste liquid 9 in the central area of ​​the polishing pad 1 is subjected to a smaller centrifugal force and a lower throwing speed, which makes it easier for tiny particles to be retained and fail to achieve a good cleaning effect. At the same time, the cleaning area formed by the rising liquid level can realize the synchronous cleaning of the grinding slurry arm 4, thereby avoiding the contamination of the grinding slurry arm 4 and preventing the formation of crystals at the slurry outlet of the grinding slurry arm 4 and causing wafer scratch defects.

[0048] In some embodiments, step S3 comprises the following steps: S31: the flow rate of the waste liquid 9 sucked away by the vacuum nozzle 32 is set to be smaller than the flow rate of the cleaning liquid sprayed through the nozzle 31, the cleaning area is gradually expanded, and part of the waste liquid 9 cannot be sucked away by the vacuum nozzle 32 in time and flows out at the circumference of the polishing pad 1, and this state is maintained for cleaning until a preset time; S32: Close the nozzle 31 and use the vacuum nozzle 32 to suck away the waste liquid 9.

[0049] By maintaining the cleaning for a period of time, the polishing pad 1 and the grinding slurry arm 4 are cleaned more thoroughly.

[0050] In some embodiments, the cleaning arm 30 is provided with a booster nozzle 311 facing the center 11 of the polishing pad near the center 11 of the polishing pad. In step S1, the nozzle 31 on the cleaning arm 30 and the booster nozzle 311 are opened simultaneously. The two nozzles work together to strengthen the cleaning force of the central area of ​​the polishing pad 1, thereby improving the cleaning efficiency and the cleaning effect of the central area.

[0051] A specific cleaning experiment example: The polishing disc 1 is dyed and coated with basic dye Rhodamine B, with a coating flow rate of 300 ml / min, a coating time of 3 min, and a rotation speed of 100 rpm for the polishing disc 1; Turn off the Rhodamine B application, turn on the polishing pad cleaning device, the flow rate of the liquid supply device 36 is 8L / min, and the pressure of the negative pressure liquid suction device of the vacuum nozzle 32 is -2Bar; Observe the cleaning process and find that the waste liquid 9 is Figure 5 The liquid flows toward the central area of ​​the polishing disc 1 and is drawn out by the vacuum suction nozzle 32 .

[0052] The experimental results verify that the polishing pad cleaning device provided by the present invention meets the design expectations.

[0053] Compared with the prior art, the present invention has the following beneficial effects: The present invention proposes a polishing pad cleaning device. By providing a polishing pad cleaning device with a cleaning arm 30, a diversion barrier 7 and a vacuum suction nozzle 32, the waste liquid 9 on the polishing pad 1 can be diverted toward the center 11 of the polishing pad, so that the waste liquid 9 is gathered as a cleaning area in the central area of ​​the polishing pad 1. By providing a booster nozzle 311 to cooperate with the nozzle 31 closest to the central area, the two nozzles work together to enhance the cleaning force of the central area, improve the cleaning efficiency and the cleaning effect of the central area, and at the same time complete the cleaning of the grinding slurry arm 4, thereby avoiding the formation of new crystals on the grinding slurry arm 4 and affecting the polishing quality of subsequent wafer products.

[0054] The present invention proposes a polishing pad cleaning method. By applying the polishing pad cleaning device provided by the present invention, the polishing pad 1 is first rinsed using the booster nozzle 311 and the nozzle 31, and then the waste liquid 9 is sucked away using negative pressure to efficiently clean the surface of the polishing pad 1. The large amount of pollutants are first rinsed to remove, and then negative pressure adsorption is performed. The combination of the two quickly removes the pollutants on the polishing pad 1 to ensure the cleaning effect and efficiency, and realizes efficient cleaning of the polishing pad 1, especially the cleaning of the central area of ​​the polishing pad 1 is more thorough, reducing the retention of tiny particles, and using the cleaning area formed by the guide barrier 7 to synchronously clean the grinding slurry arm 4, avoiding the contamination of the grinding slurry arm 4, reducing defects in the wafer processing process, and improving the yield and reliability of semiconductor products.

[0055] The above embodiments of the present invention are described in detail through examples, but the contents described are only exemplary embodiments of the embodiments of the present invention and cannot be considered to limit the scope of implementation of the embodiments of the present invention. The protection scope of the embodiments of the present invention is defined by the claims. Anyone who utilizes the technical solutions described in the embodiments of the present invention, or who, inspired by the technical solutions of the embodiments of the present invention, designs similar technical solutions within the essence and protection scope of the embodiments of the present invention to achieve the above technical effects, or who makes equal changes and improvements to the scope of application, shall still be included in the protection scope of the patent coverage of the embodiments of the present invention.

Claims

1. A polishing pad cleaning device, characterized in that: include: A cleaning arm (30), wherein the cleaning arm (30) is provided with a plurality of nozzles (31); at least one guide barrier (7), the guide barrier (7) being capable of guiding the waste liquid (9) on the polishing pad (1) toward the center (11) of the polishing pad so that the liquid level of the waste liquid (9) in the central area of ​​the polishing pad (1) rises, the slurry outlet of the grinding slurry arm (4) extending to the central area, the waste liquid (9) in the central area gathering to form a cleaning area, and being capable of cleaning the slurry outlet of the grinding slurry arm (4); A vacuum suction nozzle (32), the vacuum suction nozzle (32) is connected to the vacuum flow channel (37) and is used to provide negative pressure suction to suck away the waste liquid (9).

2. The polishing pad cleaning device according to claim 1, characterized in that: The guide barrier (7) is a liquid barrier formed by liquid sprayed by a plurality of nozzles (31).

3. The polishing pad cleaning device according to claim 2, characterized in that: The spraying surfaces of two adjacent nozzles (31) partially overlap.

4. The polishing pad cleaning device according to claim 2, characterized in that: The spraying direction of at least one nozzle (31) among the nozzles (31) is set to be towards the center (11) of the polishing pad.

5. The polishing pad cleaning device according to claim 2, characterized in that: The spraying directions of the nozzles (31) are all set to be towards the center (11) of the polishing pad.

6. The polishing pad cleaning device according to claim 1, characterized in that: The spraying direction of the nozzle (31) is opposite to the rotation direction of the polishing pad (1).

7. The polishing pad cleaning device according to claim 1, characterized in that: The cleaning arm (30) is provided with a boosting nozzle (311) facing the center (11) of the polishing pad near the center (11) of the polishing pad.

8. The polishing pad cleaning device according to claim 7, characterized in that: The spraying direction of the boosting nozzle (311) is the same as the rotation direction of the polishing pad (1).

9. The polishing pad cleaning device according to claim 1, characterized in that: The guide barrier (7) is a solid baffle (313).

10. The polishing pad cleaning device according to claim 1, characterized in that: The guide barrier (7) is a double guide barrier structure composed of a liquid barrier formed by liquid sprayed by a plurality of nozzles (31) and a solid baffle (313).

11. The polishing pad cleaning device according to claim 1, characterized in that: The opening of the vacuum suction nozzle (32) is arranged in the central area of ​​the polishing pad (1).

12. The polishing pad cleaning device according to claim 1, characterized in that: The opening of the vacuum suction nozzle (32) is arranged in the central area of ​​the polishing pad (1) and the extension area of ​​the central area, and can reach the outer circle boundary of the polishing pad (1) at most.

13. The polishing pad cleaning device according to claim 1, characterized in that: The vacuum flow channel (37) is connected to a filter (33), a filter element (38) is provided in the filter (33), the filter (33) is connected to a vacuum generator (35), and one end of the vacuum generator (35) is connected to an air source (34).

14. A polishing pad cleaning method according to any one of claims 1 to 13, characterized in that: The following steps are involved: S1: starting the rotation of the polishing pad (1), opening the nozzle (31) on the cleaning arm (30), and causing the nozzle (31) to spray cleaning liquid toward the polishing pad (1); S2: the cleaning liquid rotates with the polishing pad (1) and, under the action of the guide barrier (7), gathers toward the central area of ​​the polishing pad (1), and the liquid level rises to form a cleaning area; S3: Open the vacuum nozzle (32) and use negative pressure to suck away the waste liquid (9).

15. The polishing pad cleaning method according to claim 14, characterized in that: The step S3 comprises the following steps: S31: the flow rate of the waste liquid (9) sucked away by the vacuum suction nozzle (32) is set to be smaller than the flow rate of the cleaning liquid sprayed through the nozzle (31), the cleaning area is gradually expanded, and part of the waste liquid (9) cannot be sucked away by the vacuum suction nozzle (32) in time and flows out at the circumference of the polishing pad (1), and this state is maintained for cleaning until a preset time; S32: closing the nozzle (31) and using the vacuum nozzle (32) to suck away the waste liquid (9).

16. The polishing pad cleaning method according to claim 14, characterized in that: The cleaning arm (30) is provided with a boosting nozzle (311) facing the center (11) of the polishing pad near the center (11) of the polishing pad. In step S1, the nozzle (31) and the boosting nozzle (311) on the cleaning arm (30) are opened simultaneously.

Images