Cleaning method and cleaning device for polishing head

Abstract

The invention discloses a polishing head cleaning method which comprises the following steps that a conductive wafer bearing surface is formed on a polishing head, and charged particle pollutants are attached to the wafer bearing surface; applying voltage to the wafer bearing surface of the polishing head; and an electrolyte fluid is conveyed to the wafer bearing surface, the electrolyte fluid flows to drive the charged particle pollutants to be separated from the wafer bearing surface, and cleaning of the polishing head is achieved. The invention further discloses a polishing head cleaning device. The voltage is applied to the polishing head to promote the charged particle pollutants to be separated from the wafer bearing surface of the polishing head, so that the cleaning efficiency of the polishing head is high, and the cleaning effect is good; when the negative voltage is applied to the polishing head, the flowing electrolyte fluid continuously flushes the bearing surface of the wafer, so that the cleaning effect is better; during cleaning, flowing liquid is used for continuous flushing, so that pollutants can be immediately discharged outwards from the cleaning seat along with the liquid, and secondary pollution is avoided; and other parts of the polishing device cannot be influenced in the whole cleaning process.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor integrated circuit chip manufacturing, and in particular relates to a polishing head cleaning method and a cleaning device. Background Art

[0002] Chemical mechanical polishing (CMP) is a key technology in the integrated circuit manufacturing process, and is widely used in front-end and back-end processes including transistor manufacturing, metal wiring, and interconnect structure manufacturing. From the perspective of the materials being polished, there are Si, Cu, W, SiO2, Si3N4, etc., which are widely used in the field of integrated circuits, to the rapidly developing third-generation semiconductors such as SiC and GaN.

[0003] With the rich variety of polishing materials, especially for polishing objects with good chemical stability and high hardness, it is necessary to add high-hardness abrasives to the polishing liquid, or even add strong oxidants, and increase the polishing time. In this type of polishing conditions, the abrasives and additives in the polishing liquid will adhere to the polishing head due to electrostatic adsorption, which is easy to cause the accumulation of abrasives on the polishing head, especially the anionic and cationic surfactants (such as CTAB, SDS, etc.) in the additives, and polymers containing long carbon chains (such as PAA, PMMA, etc.). Traditional polishing head cleaning mainly uses deionized water (DIW) for rinsing, which is difficult to completely remove the abrasives and other grinding liquid additives accumulated on the polishing head. Insufficient cleaning of the polishing head will leave the abrasive on the back of the wafer during the polishing process, causing particle contamination, and more seriously, scratches on the back of the wafer. After the polishing is completed, extending the cleaning time of the polishing head for better cleaning effect will increase the overall wafer transmission time and reduce the output per unit time of the system. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the present invention provides a polishing head cleaning method and a cleaning device, which applies a voltage in the opposite direction to that when the polishing head is polishing a wafer, and cooperates with an electrolyte fluid to flush the wafer carrying surface, thereby effectively removing charged particle contaminants attached to the wafer carrying surface, with good cleaning effect and short cleaning time.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a polishing head cleaning method, comprising the following steps:

[0006] The polishing head is formed with a conductive wafer bearing surface, and the wafer bearing surface has charged particle contaminants attached thereto;

[0007] applying a voltage to the wafer-carrying surface of the polishing head;

[0008] Electrolyte fluid is delivered to the wafer carrying surface, and the flow of the electrolyte fluid drives the charged particle contaminants to separate from the wafer carrying surface, thereby achieving cleaning of the polishing head.

[0009] Further, when polishing the wafer, a positive voltage is applied to the wafer bearing surface, and when cleaning the polishing head, a positive voltage or a negative voltage is applied to the wafer bearing surface; or, when polishing the wafer, a negative voltage is applied to the wafer bearing surface, and when cleaning the polishing head, a negative voltage or a positive voltage is applied to the wafer bearing surface.

[0010] Further, when polishing the wafer, the wafer bearing surface is connected to the positive pole of the power supply, and when cleaning the polishing head, the wafer bearing surface is connected to the negative pole of the power supply; or, when polishing the wafer, the wafer bearing surface is connected to the positive pole of the power supply, and when cleaning the polishing head, the wafer bearing surface is also connected to the positive pole of the power supply.

[0011] Further, when polishing the wafer, the wafer bearing surface is charged or uncharged.

[0012] Further, in the step of applying a voltage to the wafer bearing surface, the voltage is applied continuously, or intermittently, or the voltage is applied in an alternating manner between positive and negative directions.

[0013] Further, the electrolyte fluid forms a continuous fluid column; the number of the fluid columns is one or two or more.

[0014] Further, the method includes the following steps

[0015] The polishing head is formed with a conductive wafer bearing surface, and charged particle contaminants are attached to the wafer bearing surface;

[0016] The cleaning seat is formed with a conductive area;

[0017] An electrolyte fluid is conveyed on the wafer bearing surface or / and in the conductive area, and a voltage is applied between the polishing head and the cleaning seat so that the electrolyte fluid serves as a conductive medium between the wafer bearing surface and the conductive area, and the flowing electrolyte fluid drives the charged particle contaminants to separate from the wafer bearing surface, thereby realizing the cleaning of the polishing head.

[0018] Further, the method further includes a step of bringing the polishing head and the cleaning seat closer to each other, and the distance between the two is 0 to 20 mm.

[0019] Further, the polishing head and the cleaning seat can be respectively connected to a power supply to form a conductive loop among the wafer bearing surface, the continuous electrolyte fluid, the conductive area, and the power supply.

[0020] Further, the electrolyte fluid forms a liquid film on the wafer bearing surface or / and in the conductive area, or the electrolyte fluid forms a continuous fluid column between the wafer bearing surface and the conductive area.

[0021] Further, the flow rate of the electrolyte fluid is 200 to 5000 mL / min.

[0022] Furthermore, during the polishing head cleaning step, the polishing head rotates.

[0023] Furthermore, the method also includes the following step of superimposing ultrasound on the electrolyte fluid.

[0024] Furthermore, after the polishing head is cleaned, the method further includes the step of conveying liquid to the wafer supporting surface and / or the cleaning seat to rinse them.

[0025] Furthermore, the charged particle pollutants are non-metallic and are directionally transferred along with the electrolyte fluid under the action of the electric field; or, the charged particle pollutants are metal.

[0026] Further, the cleaning seat is a polishing table, or the cleaning seat is a wafer carrier table, or the cleaning seat is a cleaning table, or the cleaning seat is a cleaning nozzle.

[0027] The present invention also discloses a polishing head cleaning device, comprising:

[0028] A polishing head having a wafer bearing surface, the wafer bearing surface being electrically conductive;

[0029] An electrolyte fluid output unit, used for outputting the electrolyte fluid;

[0030] A pressure applying unit, used for applying voltage to the wafer bearing surface of the polishing head;

[0031] When charged particle contaminants are attached to the wafer carrying surface, the pressure unit applies voltage to the wafer carrying surface, and the electrolyte fluid output unit transports electrolyte fluid to the wafer carrying surface. The flow of the electrolyte fluid drives the charged particle contaminants to separate from the wafer carrying surface, thereby cleaning the polishing head.

[0032] Furthermore, when the wafer is polished, a positive voltage is applied to the wafer carrying surface, and when the polishing head is cleaned, a positive voltage or a negative voltage is applied to the wafer carrying surface; or, when the wafer is polished, a negative voltage is applied to the wafer carrying surface, and when the polishing head is cleaned, a negative voltage or a positive voltage is applied to the wafer carrying surface.

[0033] Furthermore, when the wafer is polished, the wafer carrying surface is connected to the positive pole of the power supply, and when the polishing head is cleaned, the wafer carrying surface is connected to the negative pole of the power supply; or, when the wafer is polished, the wafer carrying surface is connected to the positive pole of the power supply, and when the polishing head is cleaned, the wafer carrying surface is also connected to the positive pole of the power supply.

[0034] Further, it further includes a cleaning seat which is formed with a conductive area. When charged particle contaminants adhere to the wafer bearing surface, the pressing unit applies a voltage to the wafer bearing surface and the conductive area, and the direction of this voltage is opposite to the voltage direction applied to the wafer bearing surface during wafer polishing. And the electrolyte fluid output unit conveys electrolyte fluid to the wafer bearing surface, and the flow of this electrolyte fluid drives the charged particle contaminants to break away from the wafer bearing surface, realizing the cleaning of the polishing head.

[0035] Further, the electrolyte fluid output unit is integrally arranged with the cleaning seat.

[0036] Further, the cleaning seat is a polishing table, or the cleaning seat is a wafer carrier, or the cleaning seat is a cleaning table, or the cleaning seat is a cleaning nozzle; the electrolyte fluid output unit is a cleaning nozzle, or a polishing fluid arm.

[0037] Further, the pressing unit is a power supply, and the polishing head and the cleaning seat can be respectively connected to the power supply to form an electrical conduction loop among the wafer bearing surface, the continuous electrolyte fluid, the conductive area, and the power supply.

[0038] The beneficial effects of the present invention are as follows: 1) Applying a voltage to the polishing head promotes the charged particle contaminants to break away from the wafer bearing surface of the polishing head, resulting in high cleaning efficiency and good cleaning effect of the polishing head; 2) While applying a negative voltage to the polishing head, the flowing electrolyte fluid continuously flushes the wafer bearing surface, and the cleaning effect is better; 3) Using flowing liquid for continuous flushing during cleaning enables the contaminants to be immediately discharged outward from the cleaning seat with the liquid and will not cause secondary pollution; 4) The entire cleaning process will not affect other components of the polishing device; 5) The cleaning process of the polishing head can be completed on the polishing pad, or on the wafer carrier, or on a separate cleaning device, which can be determined according to requirements, and there is a large selection space; 6) When the electrolyte fluid output unit and the cleaning seat are combined into one to form a cleaning nozzle, it can both output electrolyte fluid and have a conductive area / ultrasonic area, and can simultaneously convey the electrolyte fluid and current / ultrasound to the polishing head. Without adding extra equipment on the basis of the original equipment, it saves space and makes the cleaning device more controllable; 7) When the electrolyte fluid forms a fluid column, the number of fluid columns can be two or more, making the cleaning of the polishing head cleaner. For different fluid columns, functions such as ultrasonic can also be superimposed, with higher adaptability in use, and the polishing head can choose to rotate or not rotate, and the cleaning can be completed in both cases. Description of the Drawings

[0039] Figure 1 It is a schematic structural diagram of the polishing head cleaning device in Embodiment 1 and Embodiment 8 of the present invention.

[0040] Figure 2 It is a schematic structural diagram of the polishing head cleaning device in Embodiment 1 of the present invention.

[0041] Figure 3 This is a schematic structural diagram of the polishing head cleaning device in Embodiment 3 of the present invention.

[0042] Figure 4 This is a schematic structural diagram of the polishing head cleaning device in Embodiment 6 of the present invention.

[0043] Figure 5 This is the cleaning effect diagram of the present invention, which is represented by the change of the polishing head resistance with the cleaning time.

[0044] Figure 6 This is a schematic flowchart in Embodiment 9 of the present invention.

[0045] Among them, 1 - polishing head, 2 - wafer bearing surface, 3 - pressing unit, 4 - cleaning base, 41 - conductive area, 5 - electrolyte fluid, 51 - electrolyte fluid output unit, 6 - ultrasonic generating device. Detailed implementation manners

[0046] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] A polishing head cleaning method includes the following steps:

[0048] The polishing head is formed with a conductive wafer bearing surface, and charged particle contaminants are attached to the wafer bearing surface;

[0049] Apply a voltage to the wafer bearing surface of the polishing head;

[0050] Convey an electrolyte fluid to the wafer bearing surface, and the flow of the electrolyte fluid drives the charged particle contaminants to detach from the wafer bearing surface, realizing the cleaning of the polishing head.

[0051] Embodiment 1

[0052] A polishing head cleaning method includes the following steps:

[0053] The polishing head 1 is formed with a conductive wafer bearing surface 2, and charged particle contaminants are attached to the wafer bearing surface 2. The charged particle contaminants are non-metallic; the wafer bearing surface 2 is made of a conductive material, and its materials include metals, conductive polymers, carbon materials, and conductive metal and polymer composites;

[0054] A voltage is applied to the wafer bearing surface 2 of the polishing head 1, and the direction of this voltage is opposite to the direction of the voltage applied to the wafer bearing surface 2 during wafer polishing. In other words, if the voltage applied to the wafer bearing surface 2 during wafer polishing is defined as a positive voltage, then at this time, when the polishing head 1 is being cleaned, a negative voltage is applied to the wafer bearing surface 2. More specifically, during wafer polishing, the wafer bearing surface 2 is connected to the positive pole of the power supply, and when the polishing head 1 is being cleaned, the wafer bearing surface 2 is connected to the negative pole of the power supply; the voltage applied to the wafer bearing surface 2 can be a continuously applied voltage, an intermittently applied voltage, or a voltage that alternates between positive and negative, and it can be direct current or alternating current, without specific limitations, and its rated power ≥ 50W;

[0055] Of course, in other embodiments, it can also be that during wafer polishing, a negative voltage is applied to the wafer bearing surface 2, and when the polishing head 1 is being cleaned, a positive voltage is applied to the wafer bearing surface 2, without specific limitations. As Figure 1 shown, the electrolyte fluid output unit 51 conveys the electrolyte fluid 5 to the wafer bearing surface 2, and the electrolyte fluid 5 forms a continuous fluid column. The spraying angle of the electrolyte fluid 5 is not limited. Specifically, the flow rate of the electrolyte fluid 5 can be 200 - 5000 mL / min. The flow of the electrolyte fluid 5 drives the charged particle contaminants to detach from the wafer bearing surface 2. That is, when the charged particle contaminants are non-metals, they move directionally under the action of the electric field and move directionally with the electrolyte fluid 5 to detach from the wafer bearing surface 2, realizing the cleaning of the polishing head 1, and the cleaning duration is 30 - 120 s;

[0056] The number of the above-mentioned fluid columns can be one or two or more, without specific limitations;

[0057] An ultrasonic wave can also be superimposed on the electrolyte fluid to enhance the cleaning effect by using ultrasonic oscillation. As Figure 2 shown, at this time, an ultrasonic generating device 6 is provided;

[0058] Of course, the charged particle contaminants can also be metals, and they are driven by the flow of the electrolyte fluid to detach from the wafer bearing surface;

[0059] During the above process, the polishing head can be stationary or rotating.

[0060] After the cleaning of the polishing head is completed, liquid can continue to be conveyed to the wafer bearing surface to rinse it. This liquid can be deionized water or a cleaning solution, and the cleaning solution can be an inorganic acid aqueous solution, an inorganic base aqueous solution, or an inorganic salt aqueous solution, so as to avoid the accumulation of impurities and cause secondary pollution during the cleaning of the polishing head.

[0061] As Figure 5As shown, for a polishing head with a conductive wafer carrier surface, after long-term polishing, the surface resistance > 10 MΩ. When only rinsed with deionized water, the resistance of the wafer carrier surface of the polishing head is still > 10 MΩ after 60 s; while after cleaning with direct current and ultrasonic waves for only 60 s, the resistance of the wafer carrier surface of the polishing head < 10 Ω.

[0062] Example Two

[0063] The difference from Example One is that a voltage is applied to the wafer carrier surface 2 of the polishing head 1, and the direction of this voltage is the same as the voltage direction applied to the wafer carrier surface 2 during wafer polishing. In other words, if the voltage applied to the wafer carrier surface 2 during wafer polishing is defined as the positive voltage, then when cleaning the polishing head 1, a positive voltage is applied to the wafer carrier surface 2.

[0064] More specifically, during wafer polishing, the wafer carrier surface 2 is connected to the positive pole of the power supply. When cleaning the polishing head 1, the wafer carrier surface 2 is also connected to the positive pole of the power supply.

[0065] Others are the same as in Example One and will not be elaborated.

[0066] Example Three

[0067] A method for cleaning a polishing head includes the following steps:

[0068] The polishing head 1 is formed with a conductive wafer carrier surface 2, and the wafer carrier surface 2 is attached with charged particle contaminants, and these charged particle contaminants are non-metallic.

[0069] The cleaning seat 4 is formed with a conductive region 41; the cleaning seat can be a polishing table, or the cleaning seat is a wafer carrier, or the cleaning seat is a cleaning table, or the cleaning seat is a cleaning nozzle. There is no specific limitation as long as the cleaning seat has a conductive region.

[0070] As Figure 3 shown, an electrolyte fluid 5 is conveyed on the wafer carrier surface 2, so that the electrolyte fluid 5 forms a liquid film on the wafer carrier surface 2, and the polishing head 1 and the cleaning seat 4 are brought closer to each other, and the distance between the two is between 0 and 20 mm, that is, the polishing head 1 and the cleaning seat 4 can be in contact or not in contact. At this time, the conductive region 41 of the cleaning seat 4 contacts the liquid film formed by the electrolyte fluid 5, that is, the electrolyte fluid 5 fills the gap between the polishing head 1 and the cleaning seat 4. A voltage is applied between the polishing head 1 and the cleaning seat 4. In other words, a direct current or alternating current is applied between the polishing head 1 and the cleaning seat 4, so that the electrolyte fluid 5 serves as a conductive medium between the wafer carrier surface 2 and the conductive region 41. The flowing of the electrolyte fluid 5 drives the charged particle contaminants to break away from the wafer carrier surface 2, realizing the cleaning of the polishing head 1, and the cleaning duration is 30 - 120 s.

[0071] Define the voltage applied to the wafer bearing surface 2 during wafer polishing as the forward voltage. At this time, the applied voltage can be a forward voltage, a negative voltage, or a forward voltage and a negative voltage are applied alternately;

[0072] More specifically, when it is necessary to clean the impurities flowing into the gap between the wafer and the conductive cloth after the reaction, a forward voltage is applied. At this time, the impurity type is usually positively charged and can be driven by the forward voltage during cleaning. The impurities move away from the polishing head and move towards the cleaning seat to achieve cleaning; when it is necessary to clean the impurities electrostatically adsorbed on the polishing head, the impurity type is negatively charged. During cleaning, the polishing head needs to be switched to a negative voltage drive, and the cleaning seat is positively charged. At this time, the negatively charged impurities on the polishing head will move towards the cleaning seat to achieve cleaning. Of course, during the same cleaning, a forward voltage and a negative voltage can be applied respectively to clean different types of impurities, making the polishing head cleaning more thorough and clean.

[0073] Ultrasonic waves can also be superimposed on the electrolyte fluid to enhance the cleaning effect by ultrasonic vibration;

[0074] In the above process, the polishing head can be stationary or rotating.

[0075] After the polishing head cleaning is completed, liquid can continue to be transported to the wafer bearing surface and the cleaning seat to rinse them. This liquid can be deionized water or a cleaning solution, and this cleaning solution can be an inorganic acid aqueous solution, an inorganic base aqueous solution, or an inorganic salt aqueous solution, so as to avoid impurity accumulation and cause secondary pollution of the polishing head during cleaning.

[0076] Example 4

[0077] The difference from Example 3 is that the electrolyte fluid is transported in the conductive area, so that a liquid film is formed by the electrolyte fluid in the conductive area, and the polishing head and the cleaning seat are close to each other, and the distance between the two is between 0 and 20 mm. At this time, the wafer bearing surface of the polishing head contacts the liquid film formed by the electrolyte fluid, and a voltage is applied between the polishing head and the cleaning seat so that the electrolyte fluid serves as a conductive medium between the wafer bearing surface and the conductive area. The flow of the electrolyte fluid drives the charged particle contaminants to break away from the wafer bearing surface to achieve the cleaning of the polishing head.

[0078] The others are the same as in Example 3 and will not be elaborated.

[0079] Example 5

[0080] The difference from Embodiment 3 is that electrolyte fluid is delivered to both the wafer bearing surface and the conductive area, so that a liquid film is formed in the conductive area and a liquid film is formed on the wafer bearing surface. The polishing head and the cleaning seat are close to each other, and the distance between them is between 0 and 20 mm. At this time, the liquid film on the wafer bearing surface contacts the liquid film in the conductive area, and a voltage is applied between the polishing head and the cleaning seat, so that the electrolyte fluid serves as a conductive medium between the wafer bearing surface and the conductive area. The flow of the electrolyte fluid drives the charged particle contaminants away from the wafer bearing surface to achieve the cleaning of the polishing head.

[0081] Others are the same as Embodiment 2 and will not be elaborated here.

[0082] Embodiment 6

[0083] The difference from Embodiment 3 is that a continuous fluid column is formed between the wafer bearing surface 2 and the conductive area 41 by the electrolyte fluid 5, as Figure 4 shown. The flow rate of the electrolyte fluid 5 can be 200 - 5000 mL / min.

[0084] Specifically, electrolyte fluid can be delivered to the wafer bearing surface 2, and after passing through the wafer bearing surface 2, the electrolyte fluid 5 continues to flow to the conductive area 41, thereby forming a continuous fluid column between the wafer bearing surface 2 and the conductive area 41.

[0085] Alternatively, electrolyte fluid 5 can be delivered to the conductive area 41, and after passing through the conductive area 41, the electrolyte fluid 5 continues to flow to the wafer bearing surface 2, thereby forming a continuous fluid column between the conductive area 41 and the wafer bearing surface 2.

[0086] Embodiment 7

[0087] In Embodiments 3 - 6, the specific manner of applying voltage between the polishing head and the cleaning seat is not limited. In this embodiment, the polishing head and the cleaning seat can be respectively connected to the positive and negative electrodes of the power supply to form a conductive loop between the wafer bearing surface, the continuous electrolyte fluid, the conductive area, and the power supply.

[0088] Specifically, the cleaning seat has a wiring seat connected to the power supply, and can form a loop with the polishing head also connected to the power supply.

[0089] Embodiment 8

[0090] A polishing head cleaning device, comprising:

[0091] As Figure 1 shown, a polishing head 1, having a wafer bearing surface 2, and the wafer bearing surface 2 is conductive;

[0092] An electrolyte fluid output unit 51 for outputting an electrolyte fluid 5; the electrolyte fluid output by the electrolyte fluid output unit 51 can be distributed on the wafer bearing surface 2 in the form of dots, lines or surfaces;

[0093] A pressure application unit 3 for applying a voltage to the wafer bearing surface 2 of the polishing head 1; in this embodiment, the pressure application unit 3 is a power supply;

[0094] When the wafer bearing surface 2 is attached with charged particle contaminants, the pressure application unit 3 applies a voltage to the wafer bearing surface 2, the direction of this voltage is opposite to the direction of the voltage applied to the wafer bearing surface 2 during wafer polishing, and the electrolyte fluid output unit 51 conveys the electrolyte fluid 5 to the wafer bearing surface 2, and the flowing of this electrolyte fluid 5 drives the charged particle contaminants to break away from the wafer bearing surface, realizing the cleaning of the polishing head.

[0095] Embodiment Nine

[0096] The difference between this embodiment and Embodiment Eight is that the pressure application unit 3 applies a voltage to the wafer bearing surface 2, and the direction of this voltage is the same as the direction of the voltage applied to the wafer bearing surface 2 during wafer polishing.

[0097] Of course, it can also be that the pressure application unit 3 first applies a positive voltage to the wafer bearing surface 2 and then applies a negative voltage; or first applies a negative voltage and then applies a positive voltage; or alternately applies a positive voltage and a negative voltage. The above description is based on the basis of defining the voltage applied to the wafer bearing surface 2 during wafer polishing as a positive voltage.

[0098] Embodiment Ten

[0099] In Embodiment Eight and Embodiment Nine, during wafer polishing, the wafer bearing surface 2 is charged. In this embodiment, the wafer bearing surface 2 is not charged, that is, it is not charged during wafer polishing. At this time, the pressure application unit 3 applies a positive voltage or a negative voltage.

[0100] Embodiment Eleven

[0101] A polishing head cleaning device, comprising:

[0102] A polishing head 1 having a wafer bearing surface 2, and this wafer bearing surface 2 is conductive;

[0103] A cleaning seat 4 formed with a conductive area 41; this cleaning seat can be a polishing table, or the cleaning seat is a wafer carrier, or the cleaning seat is a cleaning table, or the cleaning seat is a cleaning nozzle, and there is no specific limitation as long as the cleaning seat has a conductive area;

[0104] The cleaning seat can include an ultrasonic generating device 6, and ultrasonic waves are superimposed on the electrolyte fluid through this ultrasonic generating device and then transmitted to the wafer bearing surface through the electrolyte fluid;

[0105] The electrolyte fluid output unit 51 is used to output the electrolyte fluid 5; the electrolyte fluid output unit 51 is a cleaning nozzle, or a polishing liquid arm; of course, the electrolyte fluid output unit and the cleaning seat can also be integrally arranged;

[0106] A pressure-applying unit 3 is used to apply voltage to the wafer-carrying surface 2 of the polishing head 1; in this embodiment, the pressure-applying unit is a power source, and the polishing head and the cleaning seat can be connected to the power source respectively;

[0107] When charged particle contaminants are attached to the wafer carrying surface 2, the pressure unit 3 applies voltage to the wafer carrying surface 2 and the conductive area 41, thereby forming a conductive circuit between the wafer carrying surface 2, the continuous electrolyte fluid 5, the conductive area 41, and the power supply. The direction of the voltage is opposite to the direction of the voltage applied to the wafer carrying surface 2 during wafer polishing, and the electrolyte fluid output unit 51 transports the electrolyte fluid 5 to the wafer carrying surface 2. The flow of the electrolyte fluid 5 drives the charged particle contaminants to separate from the wafer carrying surface 2, thereby achieving the cleaning of the polishing head 1.

[0108] In this embodiment, the electrolyte fluid output unit and the cleaning seat may also be combined into one.

[0109] More specifically, if Figure 6 As shown, the following steps are included:

[0110] S1, the polishing head stops just above the cleaning seat;

[0111] S2, the polishing head descends or the cleaning seat ascends, and the wafer loading surface of the polishing head approaches or contacts the conductive area of ​​the cleaning seat;

[0112] S3, when cleaning starts, the polishing head starts to rotate, and the cleaning seat (at this time, the electrolyte fluid output unit and the cleaning seat are integrally arranged) sprays the electrolyte fluid, and at the same time, a DC or AC voltage is applied between the polishing head and the cleaning seat to improve the cleaning efficiency; of course, in this process, the polishing head may not rotate, and the cleaning seat may spray the electrolyte fluid in a wide enough range, or its spraying direction may be changed by rotation;

[0113] S4, after the cleaning process is completed, the cleaning seat sprays deionized water to rinse the wafer loading surface of the polishing head and the cleaning seat;

[0114] S5, after the polishing head is cleaned, the polishing head moves away from the cleaning seat;

[0115] S6. Spray deionized water on the cleaning seat to rinse the conductive area of ​​the cleaning seat.

[0116] The above specific implementation modes are used to explain the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A polishing head cleaning method, characterized in that, comprising the following steps: The polishing head is formed with an electrically conductive wafer carrying surface, and charged particle contaminants are attached to the wafer carrying surface; Apply a voltage to the wafer carrying surface of the polishing head; Convey an electrolyte fluid to the wafer carrying surface, and the flowing of the electrolyte fluid drives the charged particle contaminants to separate from the wafer carrying surface, thereby realizing the cleaning of the polishing head.

2. The polishing head cleaning method according to claim 1, wherein: When polishing the wafer, a positive voltage is applied to the wafer carrying surface, and when cleaning the polishing head, a positive voltage or a negative voltage is applied to the wafer carrying surface; alternatively, when polishing the wafer, a negative voltage is applied to the wafer carrying surface, and when cleaning the polishing head, a negative voltage or a positive voltage is applied to the wafer carrying surface.

3. The polishing head cleaning method according to claim 1 or 2, characterized in that: When polishing the wafer, the wafer carrying surface is connected to the positive electrode of the power supply, and when cleaning the polishing head, the wafer carrying surface is connected to the negative electrode of the power supply; alternatively, when polishing the wafer, the wafer carrying surface is connected to the positive electrode of the power supply, and when cleaning the polishing head, the wafer carrying surface is also connected to the positive electrode of the power supply.

4. The polishing head cleaning method according to claim 1, characterized in that: When polishing the wafer, the wafer carrying surface is charged or uncharged.

5. The polishing head cleaning method according to claim 1 or 2 or 4, characterized in that: In the step of applying a voltage to the wafer carrying surface, the voltage is applied continuously, or intermittently, or the voltage is applied in an alternating manner of positive and negative directions.

6. The polishing head cleaning method according to claim 1 or 2 or 4, characterized in that: The electrolyte fluid forms a continuous fluid column; the number of the fluid columns is one or two or more.

7. The polishing head cleaning method according to claim 1, characterized in that: comprising the following steps, The polishing head is formed with an electrically conductive wafer carrying surface, and charged particle contaminants are attached to the wafer carrying surface; The cleaning base is formed with an electrically conductive area; Convey the electrolyte fluid on the wafer carrying surface or / and the electrically conductive area, and apply a voltage between the polishing head and the cleaning base, so that the electrolyte fluid serves as a conductive medium between the wafer carrying surface and the electrically conductive area, and the flowing of the electrolyte fluid drives the charged particle contaminants to separate from the wafer carrying surface, thereby realizing the cleaning of the polishing head.

8. The polishing head cleaning method according to claim 7, characterized in that: It further includes the step of bringing the polishing head and the cleaning base closer to each other, and the distance between the two is 0 to 20 mm.

9. The polishing head cleaning method according to claim 7, characterized in that: The polishing head and the cleaning base can be respectively connected to the power supply to form a conductive loop among the wafer carrying surface, the continuous electrolyte fluid, the electrically conductive area, and the power supply.

10. The polishing head cleaning method according to claim 7, characterized in that: The electrolyte fluid forms a liquid film on the wafer carrying surface or / and the electrically conductive area, or the electrolyte fluid forms a continuous fluid column between the wafer carrying surface and the electrically conductive area.

11. The polishing head cleaning method according to claim 1 or 10, characterized in that: The flow rate of the electrolyte fluid is 200 to 5000 mL / min.

12. The polishing head cleaning method according to claim 1 or 7, characterized in that: In the step of cleaning the polishing head, the polishing head rotates.

13. The polishing head cleaning method according to claim 1 or 7, characterized in that: It further includes the following step of superimposing ultrasonic waves on the electrolyte fluid.

14. The polishing head cleaning method according to claim 1 or 7, characterized in that: After the cleaning of the polishing head, it further includes the step of conveying a liquid to the wafer carrying surface and / or the cleaning base to rinse them.

15. The polishing head cleaning method according to claim 1 or 7, characterized in that: The charged particle contaminants are non-metallic and are directionally transferred along with the electrolyte fluid under the action of an electric field; or the charged particle contaminants are metallic.

16. The polishing head cleaning method according to claim 7, wherein: The cleaning base is a polishing table, or a wafer stage, or a cleaning table, or a cleaning nozzle.

17. A polishing head cleaning device, characterized in that, including: a polishing head having a wafer carrying surface that is electrically conductive; an electrolyte fluid output unit for outputting an electrolyte fluid; a pressure application unit for applying a voltage to the wafer carrying surface of the polishing head; When charged particle contaminants adhere to the wafer bearing surface, the pressure applying unit applies a voltage to the wafer bearing surface, and the electrolyte fluid output unit conveys an electrolyte fluid to the wafer bearing surface. The flow of the electrolyte fluid drives the charged particle contaminants away from the wafer bearing surface, achieving the cleaning of the polishing head.

18. The polishing head cleaning device according to claim 17, wherein: During wafer polishing, a positive voltage is applied to the wafer bearing surface. Then, during polishing head cleaning, a positive voltage or a negative voltage is applied to the wafer bearing surface; or, during wafer polishing, a negative voltage is applied to the wafer bearing surface, and during polishing head cleaning, a negative voltage or a positive voltage is applied to the wafer bearing surface.

19. The polishing head cleaning device according to claim 17 or 18, characterized in that: During wafer polishing, the wafer bearing surface is connected to the positive electrode of the power supply. During polishing head cleaning, the wafer bearing surface is connected to the negative electrode of the power supply; or, during wafer polishing, the wafer bearing surface is connected to the positive electrode of the power supply, and during polishing head cleaning, the wafer bearing surface is also connected to the positive electrode of the power supply.

20. The polishing head cleaning device according to claim 17, wherein: It further includes a cleaning base which has a conductive area. When charged particle contaminants adhere to the wafer bearing surface, the pressure applying unit applies a voltage to the wafer bearing surface and the conductive area, and the direction of this voltage is opposite to the voltage applied to the wafer bearing surface during wafer polishing. The electrolyte fluid output unit conveys an electrolyte fluid to the wafer bearing surface, and the flow of the electrolyte fluid drives the charged particle contaminants away from the wafer bearing surface, achieving the cleaning of the polishing head.

21. The polishing head cleaning device according to claim 20, wherein: The electrolyte fluid output unit is integrally provided with the cleaning base.

22. The polishing head cleaning device according to claim 20, characterized in that: The cleaning base is a polishing table, or the cleaning base is a wafer stage, or the cleaning base is a cleaning table, or the cleaning base is a cleaning nozzle; The electrolyte fluid output unit is a cleaning nozzle or a polishing liquid arm.

23. The polishing head cleaning device according to claim 20, wherein: The pressure applying unit is a power supply, and the polishing head and the cleaning base can be respectively connected to the power supply to form an electrical conduction loop among the wafer bearing surface, the continuous electrolyte fluid, the conductive area, and the power supply.

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