Cleaning device and cleaning method for CMP (chemical mechanical polishing) chamber

Abstract

The invention relates to the technical field of CMP polishing chamber cleaning, and provides a cleaning device and a cleaning method for a CMP polishing chamber, a polishing unit is accommodated in the polishing chamber, and the polishing unit comprises a wafer loading cup and a polishing head. The nozzles are located in the polishing cavity and comprise the wafer loading cup cleaning nozzle and the polishing head cleaning nozzle which are used for spraying out fluid to clean the wafer loading cup and the polishing head respectively, and the fluid sprayed out of the nozzles is liquid and / or gas and / or a gas-liquid mixture. By means of the technical scheme, the problems that in the prior art, a CMP polishing cavity cleaning device consumes much cleaning liquid and is not obvious in cleaning effect are solved.

Description

Technical Field

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

[0002] CMP (Chemical Mechanical Polishing) can be used to make planar components in the process of manufacturing semiconductor devices. It uses a large amount of polishing liquid during mechanical polishing. It is a combination of mechanical grinding and chemical etching. It forms a smooth surface on the surface of the ground medium by means of ultra-fine ion grinding and chemical etching of the polishing liquid.

[0003] A large amount of polishing liquid is used in CMP. The polishing liquid is a chemical solution, also known as slurry. During the polishing process, the polishing liquid will splash onto various modules in the chamber, such as the wafer loading cup, polishing head, dresser, etc. If the splashed polishing liquid is not treated for a long time, it will accumulate, dry and form crystals on the surface of the component. Then, as the component moves over the polishing pad, the crystals will fall off onto the polishing pad, causing the risk of scratching the wafer.

[0004] In some manufacturing processes, a highly viscous polishing liquid is used. When the polishing liquid splashes onto the surface of the wafer loading cup, it will remain on the surface of the carrier if it is not cleaned in time. After the wafer is polished, it is placed on the carrier and in contact with it, which will form a defect of polishing liquid residue. The subsequent process of transferring the wafer from the polishing unit to the subsequent cleaning unit takes time. During this period, the surface of the wafer is exposed, and some reactions may occur, causing the viscosity of the residual polishing liquid to increase further. The residual polishing liquid cannot be completely removed in the post-cleaning process.

[0005] Therefore, an automatic cleaning device is provided in the existing CMP station. However, there are many defects in the existing cleaning device, for example: 1. Cleaning is generally done regularly at intervals, which makes it relatively easy for the residual polishing liquid to form crystals. Cleaning after the polishing liquid forms crystals will increase the difficulty of cleaning, and a more powerful contact cleaning is required. It may not be clean, and it is easy to scratch the surface of the components in the polishing chamber; 2. The coverage area is not accurate during cleaning. Blindly cleaning a large area will not only waste a lot of cleaning liquid (generally clean water, deionized water, acid solution, alkaline solution or liquid composed of a combination thereof, etc.), but the cleaning is generally done by mechanical contact and cleaning liquid flushing, which consumes a lot of cleaning liquid and does not improve the cleaning effect; 3. It may cause many derivative problems such as water ingress into the spindle (the rotating shaft of the polishing disk or the connecting shaft between the pneumatic component and the polishing head, etc.); 4. After cleaning, droplets are easily formed on the surface of each part in the polishing chamber, and the droplets fall on the wafer loading cup or the polishing disk and other components, which are easy to form stains, and then easily contact the wafer and remain on the wafer surface, increasing the difficulty of cleaning the wafer.

[0006] Therefore, there is an urgent need for a CMP polishing chamber cleaning device that can save cleaning liquid, reduce the generation of cleaning wastewater, and has a good cleaning effect without residual droplets. Summary of the invention

[0007] In order to solve the above problems, the embodiments of the present invention provide a cleaning device and a cleaning method for a CMP polishing chamber, which solves the problem that the CMP polishing chamber cleaning device in the prior art consumes a lot of cleaning liquid and has an insignificant cleaning effect.

[0008] According to one aspect of the present invention, a cleaning device for a CMP polishing chamber is provided, wherein the polishing chamber contains a polishing unit, wherein the polishing unit includes a wafer loading cup and a polishing head;

[0009] The cleaning device includes:

[0010] The nozzle is located in the polishing chamber, and the nozzle includes a wafer loading cup cleaning nozzle and a polishing head cleaning nozzle, which are respectively used to spray fluid to clean the wafer loading cup and the polishing head. The fluid sprayed by the nozzle is liquid and / or gas and / or a gas-liquid mixture.

[0011] In some embodiments, the polishing head has an upper surface and a side surface; the polishing head cleaning nozzle includes a first nozzle and a second nozzle, the first nozzle and the second nozzle are both located on one side of the polishing head, the first nozzle is used to clean the upper surface, and the second nozzle is used to clean the side surface.

[0012] In some embodiments, the first nozzle is used to spray fan-shaped fluid; and the second nozzle is used to spray cone-shaped fluid.

[0013] In some embodiments, the wafer loading cup cleaning nozzle includes a fourth nozzle, the fourth nozzle is disposed at one side of the wafer loading cup, and the fourth nozzle is used to clean the upper surface of the wafer loading cup.

[0014] In some embodiments, the nozzle is used to spray out the gas-liquid mixture, the liquid and the gas in sequence.

[0015] In some embodiments, the ratio of gas to liquid in the gas-liquid mixture sprayed from the nozzle is adjustable.

[0016] In some embodiments, the cleaning device for a CMP polishing chamber further includes: a main body disposed in the polishing chamber, the main body having a fluid channel, the fluid channel having a fluid outlet and a fluid inlet, the nozzle disposed on the main body, and the inlet of the nozzle connected to the fluid outlet.

[0017] In some embodiments, the fluid inlet includes a liquid inlet and a gas inlet, the liquid inlet is used to communicate with a liquid source, and the gas inlet is used to communicate with a gas source; flow valves are provided between the liquid inlet and the liquid source and between the gas inlet and the gas source.

[0018] According to another aspect of the present invention, a cleaning method for a CMP polishing chamber is also provided. Using the cleaning device, the cleaning method comprises the following steps:

[0019] S1: controlling the nozzle to spray fluid to clean the surface of the polishing unit;

[0020] S2: transferring the wafer to the wafer loading cup in the polishing chamber;

[0021] S3: the polishing head picks up the wafer and moves the wafer onto the polishing pad to perform chemical mechanical polishing. During the process of the polishing head picking up the wafer and moving the wafer onto the polishing pad and / or performing chemical mechanical polishing on the wafer, the wafer loading cup cleaning nozzle sprays fluid to clean the surface of the wafer loading cup;

[0022] S4: the wafer loading cup cleaning nozzle stops cleaning the wafer loading cup, the wafer chemical mechanical polishing is finished, the polishing head carries the wafer and moves to the wafer loading cup. While the polishing head carries the wafer and moves to the wafer loading cup, the polishing head cleaning nozzle sprays fluid to clean the surface of the polishing head;

[0023] S5: The wafer is transferred out of the polishing chamber, and the polishing head cleaning nozzle discharges fluid to clean the surface of the polishing head;

[0024] S6: Repeat S2 to S5.

[0025] In some embodiments, the nozzle first sprays a gas-liquid mixture, then sprays liquid, and finally sprays gas.

[0026] In some embodiments, a plurality of the main bodies are arranged around the polishing head. When cleaning the polishing head, the cleaning is performed according to any one of the following steps:

[0027] A1: Simultaneously open the polishing head cleaning nozzles on the plurality of main bodies around the polishing head to clean the polishing head;

[0028] A2: Sequentially open the polishing head cleaning nozzles on each of the main bodies along the circumferential direction of the polishing head to clean the polishing head until all the polishing head cleaning nozzles on each of the main bodies are opened;

[0029] A3: Open the polishing head cleaning nozzle on one of the main bodies to clean the polishing head. After cleaning for a period of time a, close the polishing head cleaning nozzle. Open the polishing head cleaning nozzle on another adjacent main body along the rotating direction or the opposite direction of the polishing head to clean the polishing head. After cleaning for a time b, close the polishing head cleaning nozzle, and so on in sequence and in a cycle;

[0030] Any sequential combination of A1, A2, and A3.

[0031] In some embodiments, in step A3, a = b.

[0032] In some embodiments, in step A3, when the polishing head rotates, the polishing head cleaning nozzles on the plurality of main bodies are sequentially opened to clean the same area of the polishing head.

[0033] In some embodiments, if the rotation speed of the polishing head is constant, then a = b; if the rotation speed of the polishing head increases, then a < b; if the rotation speed of the polishing head decreases, then a > b.

[0034] According to the above technical solutions, the beneficial effects of the present invention are as follows:

[0035] (1) Perform refined cleaning on the surface of the wafer loading cup and the polishing head, improve the cleanliness near the wafer, reduce the risk of scratching or staining the wafer surface, improve the cost performance of the cleaning liquid utilization, and avoid derivative problems such as spindle water ingress caused by blind cleaning.

[0036] The wafer loading cup and polishing head are key components that are in direct contact with the wafer. The nozzle will clean the surface of the wafer loading cup and the surface of the polishing head in a targeted short cycle. The short cycle can be cleaning after contacting the wafer once, or cleaning after contacting the wafer twice, etc. This greatly shortens the cycle. Even if there is residual polishing liquid, there will be no crystallization and other difficult-to-clean substances. It can be easily cleaned after flushing with the nozzle. While improving the cleanliness near the wafer in the polishing chamber, there will not be more consumption of cleaning liquid. Because it is more targeted, it can greatly avoid derivative problems such as water intrusion into the spindle.

[0037] (2) The specific order of fluid ejection from the nozzle is clarified as gas-liquid mixture first, liquid second, and gas last, which improves the cleaning effect and efficiency and reduces the consumption of cleaning fluid and the amount of cleaning wastewater generated.

[0038] In the initial stage, the gas-liquid mixture can use the impact and stirring of the gas and the dissolution and penetration ability of the liquid to preliminarily decompose and peel off various dirt on the surface, creating favorable conditions for the subsequent cleaning steps. After the gas-liquid mixture acts, although some dirt on the surface has been removed, some fine particles, impurities dissolved in the liquid, and bubbles may still remain. At this time, the sprayed liquid can completely wash away these remaining dirt and stains with its large flow rate and good fluidity, ensuring that the surface cleanliness reaches a higher level. Finally, the gas sprayed can quickly blow off the droplets on the surface to prevent the formation of water stains. This sequential setting makes the cleaning process form a logically rigorous and interlocking system, which can not only comprehensively and efficiently clean a variety of common pollutants on the surface of the CMP chamber and significantly improve the cleanliness, but also reduce the consumption of cleaning liquid and the amount of sewage generated after cleaning because the amount of gas is increased in the gas-liquid mixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in describing the embodiments of the present invention. Obviously, the drawings described below are only some exemplary embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on the contents of the exemplary embodiments of the present invention and these drawings without creative work.

[0040] Figure 1 Schematic diagram of a top view of a CMP polishing chamber in the present invention;

[0041] Figure 2 is another schematic top view of the CMP polishing chamber of the present invention, wherein a cleaning device is shown;

[0042] Figure 3 It is a schematic diagram of the structure of the polishing head part in the present invention;

[0043] Figure 4 It is a schematic diagram of the structure of the wafer loading cup part of the present invention;

[0044] Figure 5 It is a schematic diagram of the structure of the main part of the cleaning device in the present invention;

[0045] Figure 6 It is a schematic diagram of the fluid conveying principle structure of the cleaning device in the present invention;

[0046] Figure 7 It is a schematic diagram of the cross-sectional structure of the double-branch channel of the main body in the present invention;

[0047] Figure 8 It is a schematic diagram of a cross-sectional structure of a branch channel of the main body in the present invention;

[0048] Fig. 9 It is a schematic diagram of the second cross-sectional structure of the branch channel of the main body in the present invention;

[0049] Fig.10 This is a schematic diagram of the structure of the regulating valve when the fluid channel is open in the present invention;

[0050] Fig.11 This is a schematic diagram of the structure of the regulating valve when the fluid channel is closed in the present invention;

[0051] Fig.12 It is a schematic diagram of the limiting surface structure of the regulating valve in the present invention;

[0052] Fig.13 It is a schematic diagram of the cleaning process in the present invention.

[0053] In the figure: 1-polishing chamber, 2-polishing unit, 21-wafer loading cup, 22-polishing head, 221-upper surface, 222-side surface, 23-pneumatic component, 231-lower surface, 24-polishing disk, 25-dressing device, 26-liquid supply arm, 3-surface, 41-nozzle, 411-first nozzle, 412-second nozzle, 413-third nozzle, 414-fourth nozzle, 42-main body, 43-fluid channel, 431-fluid outlet, 432-fluid inlet, 433-liquid inlet, 434-gas inlet, 435-flow valve, 436-branch channel one, 437-branch channel two, 438-regulating valve, 439-limiting surface, 440-mounting hole, 441-reserved hole. DETAILED DESCRIPTION

[0054] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention.

[0055] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically shown, or only one of them is marked. In this article, "one" not only means "only one", but also means "more than one", and "several" includes "two" and "more than two".

[0056] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0058] In the description of this embodiment, terms such as "up", "down", "left", and "right" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0059] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0060] Reference Figure 1, which shows a CMP polishing chamber 1, in which only one polishing unit 2 is shown. It is understandable that there can be multiple polishing units 2 in the CMP polishing chamber at the same time, and multiple wafers can be polished at the same time. The polishing here usually refers to chemical mechanical polishing. Each polishing unit 2 has a polishing disc 24, a dressing device 25, a polishing head 22 and a wafer loading cup 21. The polishing head 22 takes the wafer from the wafer loading cup 21 by adsorption or mechanical clamping, and abuts against the polishing pad on the polishing disc 24 under pressure. At the same time, with the aid of polishing liquid, the rotating polishing disc 24 performs a mechanical chemical polishing process on the wafer. Optionally, the polishing chamber 1 is a relatively closed area for limiting the influence of external contaminants on the CMP process and preventing the chemical polishing liquid in the CMP process from splashing to the outside. The wafer on the wafer loading cup 21 is moved to the subsequent process equipment by a manipulator or a robot.

[0061] According to an embodiment of the present invention, in order to clean the polishing liquid in time, an embodiment of the present invention provides a cleaning device for a CMP polishing chamber. Figure 2 , Figure 2 Another schematic top view of the CMP polishing chamber of the present invention, in which a cleaning device is shown. A surface 3, a nozzle 41 and a polishing unit 2 are provided in the polishing chamber 1. The polishing unit 2 includes a wafer loading cup 21, a polishing disk 24, a polishing pad and a polishing head 22. The surface 3 includes the inner surface of the polishing chamber 1 and / or the surface of the wafer loading cup 21 and / or the surface of the polishing disk 24 and / or the surface of the polishing head 22 and / or the surface of the polishing pad. The nozzle 41 is located in the polishing chamber 1, and the nozzle 41 is used to spray a fluid to clean the surface 3. The fluid sprayed by the nozzle 41 is a liquid and / or a gas and / or a gas-liquid mixture.

[0062] In this embodiment, the polishing disc 24 is located on one side of the wafer loading cup 21, and the polishing head 22 can be arranged to reciprocate between the polishing disc and the wafer loading cup 21. The polishing head 22 is used to absorb the wafer and transfer it between the wafer loading cup 21 and the polishing disc 24. Optionally, the polishing head 22 clamps the wafer by mechanical clamping to transfer it between the wafer loading cup 21 and the polishing disc. The polishing pad is located on the polishing disc 24, and the polishing of the wafer is completed by the polishing pad. The nozzle 41 can spray fluid to achieve flushing of the surface 3, prevent the polishing liquid from remaining on the surface 3, and accumulate to form crystals, thereby providing a clean environment for wafer processing and preventing scratches on the wafer.

[0063] According to one embodiment of the invention, the nozzle 41 includes a wafer loading cup cleaning nozzle for cleaning the surface of the wafer loading cup 21 , and a polishing head cleaning nozzle for cleaning the surface of the polishing head 22 .

[0064] In this embodiment, it is extremely important to specify that the nozzle 41 is used to clean the surface of the wafer loading cup 21 and the surface of the polishing head 22. The wafer loading cup 21 bears the heavy responsibility of carrying and transporting the wafer in the entire CMP process. Any tiny contamination on its surface may be transferred to the wafer during the placement and transportation of the wafer, resulting in scratches on the wafer surface, impurity adsorption and other problems, which seriously affect the flatness and finish of the wafer and the subsequent chip manufacturing process. The polishing head 22 is a component that directly contacts the wafer and applies pressure to achieve the polishing action. The cleanliness of its surface plays a decisive role in the pressure uniformity and polishing effect. If there is dirt on the surface of the polishing head 22 or the residual polishing liquid is unevenly distributed, the pressure on the wafer during the polishing process will be inconsistent, resulting in local over-polishing or insufficient polishing, and ultimately reducing the yield rate of the wafer. Therefore, targeted cleaning of these two key surfaces can accurately eliminate the pollution sources that may affect the CMP process accuracy and wafer quality, greatly improving the stability and reliability of the process.

[0065] In addition, because the wafer loading cup 21 and the polishing head 22 are key components that are in direct contact with the wafer, the nozzle 41 will clean the surface of the wafer loading cup 21 and the surface of the polishing head 22 in a targeted short cycle. The short cycle can be cleaning after contacting the wafer once, or cleaning after contacting the wafer twice, etc., which greatly shortens the cycle. Even if there is residual polishing liquid, there will be no crystallization and other difficult-to-clean substances, and it can be easily cleaned by flushing with the nozzle 41. Because the surface to be cleaned is smaller and more targeted than the entire interior of the polishing chamber 1, even if the cleaning cycle is short, it will not consume too much cleaning liquid, and it is difficult to cause problems such as water ingress to the spindle. After a long cycle (determined according to the actual formation time of the residual polishing liquid in the polishing chamber 1), the entire polishing chamber 1 can be thoroughly cleaned, so that the risk of scratching the wafer and the probability of stains on the wafer surface can be reduced while consuming almost the same cleaning liquid.

[0066] Furthermore, the wafer loading cup cleaning nozzle and the polishing head cleaning nozzle are controlled to be rinsed asynchronously or synchronously. Usually a typical wafer transfer process is: the polishing head picks up the wafer from the wafer loading cup 21, the polishing head carries the wafer for polishing, and after the polishing is completed, the polishing head puts the wafer back into the wafer loading cup, and the manipulator takes the wafer from the wafer loading cup and transfers it to the subsequent process equipment. In this polishing process, the required time is relatively long. In particular, when the polishing head carries the wafer for polishing, the wafer loading cup is in an idle waiting state. If there is polishing liquid remaining on the wafer loading cup, it will solidify, dry and form crystals, and then move with the components to the top of the polishing pad, and the crystals will fall off onto the polishing pad, causing the risk of scratching the wafer. Therefore, it is desirable that in the process of the polishing head carrying the wafer for polishing, the wafer loading cup 21 is cleaned independently at the same time, and it cannot be cleaned until the overall polishing process is completed. Similarly, it is desirable that the polishing head is cleaned independently immediately after the polishing head puts the wafer back into the wafer loading cup.

[0067] Therefore, the nozzle 41 includes a wafer loading cup cleaning nozzle for cleaning the surface of the wafer loading cup 21, and a polishing head cleaning nozzle for cleaning the surface of the polishing head 22. This can ensure that the wafer loading cup and the polishing head can be cleaned asynchronously respectively, greatly shortening the cleaning cycle. Even if there is residual polishing liquid, crystals and other difficult-to-clean substances will not appear, and they can be easily cleaned after being flushed by the nozzle 41.

[0068] The polishing head 22 has an upper surface 221 and a side surface 222. Optionally, the polishing head cleaning nozzle includes a first nozzle 411 and a second nozzle 412, both of which are located at one side of the polishing head 22, the first nozzle 411 is used to clean the upper surface 221, and the second nozzle 412 is used to clean the side surface 222.

[0069] In this embodiment, the surface of the polishing head 22 is further subdivided into an upper surface 221 and a side surface 222, and a first nozzle 411 and a second nozzle 412 are configured for cleaning respectively. This design embodies a refined cleaning concept. The upper surface 221 of the polishing head 22 is an area where the sputtered polishing liquid is easily left, and the polishing liquid is easily crystallized. The first nozzle 411 specifically cleans the upper surface 221 area, which can greatly reduce the risk of the residual polishing liquid forming crystals and falling onto the polishing plate 24 or the wafer loading cup 21 to scratch the wafer. The first nozzle 411 sprays a fan-shaped fluid, which can evenly spread the cleaning medium on the upper surface with a large coverage area, ensuring that every part of the upper surface can be fully cleaned, effectively removing possible tiny particles, residual chemicals, etc.

[0070] The side surface of the polishing head 22 is not only prone to residual sputtered polishing liquid, but also the polishing liquid is easy to form high-concentration polishing liquid droplets after gathering on the side surface, and drip onto the wafer loading cup 21 or the polishing plate 24. Especially after dripping onto the wafer loading cup 21, the wafer is placed on the wafer loading cup 21, and the high-concentration polishing liquid droplets are easy to contaminate the wafer surface, increasing the difficulty of post-cleaning of the wafer. The second nozzle 412 is lower than the first nozzle 411 and is used to clean the side of the polishing head 22. The fluid sprayed by the second nozzle 412 is cone-shaped.

[0071] In this embodiment, Figure 2 and Figure 3 As shown, the design of the first nozzle 411 spraying fan-shaped fluid cleverly adapts to the cleaning needs of the upper surface of the polishing head. The fan-shaped fluid can form a wider coverage area in the horizontal direction when sprayed, similar to the shape of a fan unfolded, so that the cleaning fluid can cover a larger area of ​​the upper surface at one time. This large-area coverage not only improves the cleaning efficiency and reduces the cleaning time, but also ensures the uniformity of the cleaning process. During the cleaning process, the fan-shaped fluid evenly impacts the upper surface, so that the cleaning liquid can fully contact the dirt on the surface and carry it away, avoiding the residue problem caused by inadequate local cleaning.

[0072] For the second nozzle 412 to spray a conical fluid to clean the side surface 222, the conical fluid at the outlet of the second nozzle 412 has a smaller diameter. The conical fluid shape can gradually disperse the fluid during movement and gradually expand its diameter, so that the flow rate will gradually decrease. The flushing force is relatively gentle and can cover a portion of the upper and lower sides of the side surface 222.

[0073] Optionally, the polishing head cleaning nozzle further includes a third nozzle 413, and the third nozzle 413 is located at one side of the polishing head 22. The third nozzle 413 is used to clean the lower surface 231 of the pneumatic component 23 above the polishing head 22. The fluid sprayed by the third nozzle 413 is fan-shaped.

[0074] In this embodiment, adding a third nozzle 413 for cleaning the lower surface 231 of the pneumatic assembly 23 above the polishing head 22 is an important supplement to the integrity of the entire cleaning system. The pneumatic assembly 23 plays a key control role in the operation of the polishing head 22, such as providing precise pressure regulation for the polishing head 22, controlling its motion trajectory, etc. The lower surface 231 of the pneumatic assembly 23 is prone to adsorb dust, oil, and polishing liquid residues that may splash from the polishing head or other components during long-term operation. If these pollutants are not cleaned in time, they will gradually accumulate and may enter the internal precision structure of the pneumatic assembly, causing wear, blockage or performance degradation of the pneumatic components. For example, dust particles may hinder the normal opening and closing of the pneumatic valve, affect the precise control of the gas flow, and then make the pressure of the polishing head unstable, which ultimately has a serious negative impact on the polishing quality of the wafer. By spraying a fan-shaped fluid from the third nozzle 413 to clean its lower surface 231, these potential sources of pollution can be effectively removed to maintain the good operation of the pneumatic assembly 23.

[0075] In addition, because the pneumatic component 23 is located above the polishing head 22, the polishing liquid remaining on the pneumatic component 23, whether it forms droplets or polishing liquid, may cause scratches to the wafer, which is not conducive to maintaining the cleanliness and flatness of the wafer surface.

[0076] In this embodiment, see Figure 4 The wafer loading cup cleaning nozzle includes a fourth nozzle 414 . The fourth nozzle 414 is disposed on one side of the wafer loading cup 21 . The fourth nozzle 414 is used to clean the upper surface of the wafer loading cup 21 .

[0077] In this embodiment, the fourth nozzle 414 is used to clean the upper surface of the wafer loading cup 21, which embodies the refined cleaning concept. The upper surface of the wafer loading cup 21 is the area where the wafer is directly placed, and its flatness and cleanliness are crucial for the initial positioning and fixation of the wafer. The fourth nozzle 414 sprays a fan-shaped fluid, which can evenly spread the cleaning medium on the upper surface with a large coverage area, ensuring that every part of the upper surface can be fully cleaned, effectively removing possible tiny particles, residual chemicals, etc., and providing a clean and stable placement base for the wafer.

[0078] In a further optional embodiment, the fluid sprayed from the nozzle 41 is at least one of a liquid (i.e., a cleaning liquid), a gas, and a gas-liquid mixture, giving the device a multifunctional cleaning capability. Liquid can carry away soluble dirt, residual polishing liquid, and tiny particle impurities on the surface by virtue of its fluidity and solubility; gas can generate impact force when sprayed at high speed, blowing off some loosely attached pollutants, and can also be used to dry the surface after cleaning to avoid the problem of incomplete cleaning caused by residual water stains; the gas-liquid mixture combines the advantages of both, and the disturbance of the gas can make the liquid better penetrate into some hard-to-reach gaps and corners, enhancing the cleaning effect, and the gas-liquid mixture has a gas added, which improves the cleaning effect while reducing the proportion of cleaning liquid used. Through such an overall design, the device can fully maintain the cleanliness of the surfaces of various components in the polishing chamber 1, providing a strong guarantee for high-quality wafer processing.

[0079] Optionally, the nozzle 41 is used to spray out the gas-liquid mixture, the liquid and the gas in sequence.

[0080] In this embodiment, determining the cleaning sequence in which the nozzle 41 sprays out the gas-liquid mixture, the liquid and the gas in sequence is a scientific process that has been carefully designed.

[0081] The gas-liquid mixture plays an important role in the initial stage of cleaning. The presence of gas makes it expandable and turbulent to a certain extent, and can produce a small explosion effect and a strong stirring effect when it comes into contact with the surface to be cleaned. This effect can loosen and break the dirt layer on the surface, and the impurity particles that were originally tightly attached to the surface are dispersed. At the same time, the liquid component can use its solubility and fluidity to quickly penetrate into the dirt and wrap it up. For example, for some hard dirt shells formed by the drying of the polishing liquid, the gas-liquid mixture can effectively break them into smaller fragments, laying a good foundation for the subsequent cleaning steps.

[0082] The liquid that is then sprayed out is mainly responsible for the task of comprehensive flushing. With its own fluidity and large flow rate, it can thoroughly flush away the dirt particles, broken impurities and pollutants dissolved in the liquid that remain after being treated by the gas-liquid mixture, ensuring that there is no visible dirt remaining on the surface. The sprayed liquid can also clean away the bubble stains that may be produced by the gas-liquid mixture.

[0083] The last gas ejected plays the role of blowing off the droplets of cleaning liquid or drying the surface during the cleaning process. The high-speed flowing gas can blow off the droplets and prevent water stains from staying on the surface. In the CMP process environment, water stains may react with residual chemicals to cause surface corrosion or form water stains, affecting the quality of the wafer and the hygiene of the polishing chamber. This sequence setting makes the cleaning process from decontamination, rinsing to blowing off droplets form a complete and efficient system, which can meet the strict requirements of the CMP chamber for surface cleanliness and provide ideal surface conditions for subsequent polishing processes or wafer processing.

[0084] In addition, since the gas-liquid mixture contains a certain ratio of liquid to gas, this can reduce the consumption of cleaning fluid to a certain extent and improve the cleaning effect.

[0085] Optionally, the ratio of gas to liquid in the gas-liquid mixture sprayed from the nozzle 41 is adjustable.

[0086] In this embodiment, the adjustable ratio of gas and liquid in the gas-liquid mixture sprayed by the nozzle 41 brings high flexibility and adaptability to the cleaning process. When facing different pollution conditions, the gas-liquid ratio can be accurately adjusted according to actual needs. For example, when there are a large number of loose particle dirt on the surface of the polishing chamber, such as abrasive dust generated during the polishing process, the gas ratio can be appropriately increased. A higher ratio of gas can produce a stronger airflow impact when the mixture is sprayed out, like a "strong wind" to quickly blow these loose particles away from the surface, and the disturbance of the gas also helps the liquid to better penetrate into the gaps where the particles accumulate and completely remove them. When the surface is mainly some residual polishing liquid or chemical dirt with high viscosity, the liquid ratio needs to be increased. More liquid can fully dissolve and decompose these sticky dirts with its dissolving and emulsifying ability, so that they are detached from the surface and flow away with the liquid. In addition, the gas-liquid ratio can also be adjusted in different cleaning stages. In the pre-cleaning stage at the beginning of cleaning, the gas ratio can be appropriately increased to quickly loosen the dirt; in the deep cleaning stage, the liquid ratio is increased to ensure that the dirt is completely removed. This adjustable ratio feature enables the device to be optimally configured for various complex pollution conditions and cleaning requirements, which not only improves the cleaning effect, but also saves cleaning resources, reduces cleaning costs, and improves the economy and environmental protection of the entire CMP process.

[0087] In one embodiment of the present invention, see Figure 3 and Figure 5-6 The cleaning device further comprises a plurality of main bodies 42, which are arranged in the polishing chamber 1, and have a fluid channel 43, and the fluid channel 43 has a fluid outlet 431 and a fluid inlet 432. A nozzle 41 is arranged on the main body 42, and the inlet of the nozzle 41 is connected to the fluid outlet 431.

[0088] In this embodiment, the main body 42 and the fluid channels 43 provide stable and efficient guarantee for the fluid supply of the entire cleaning device. The main body 42 serves as the core framework of the device, and the fluid channels 43 inside it smoothly convey the fluid required for cleaning from the source end to each nozzle.

[0089] Optionally, there are several main bodies 42, such as three, four, or six. The several main bodies 42 are located at different positions in the polishing chamber 1 that need to be cleaned. While meeting the cleaning requirements of different positions, the cleaning fluid can cover more comprehensively, and the cleaning efficiency and cleanliness are higher.

[0090] A plurality of main bodies 42 are evenly arranged around the polishing head 22. When cleaning the polishing head 22, the cleaning is carried out according to the following steps:

[0091] A1: Simultaneously open the polishing head cleaning nozzles on the plurality of main bodies 42 around the polishing head 22 to clean the polishing head 22; or

[0092] A2: Sequentially open the polishing head cleaning nozzles on each main body 42 along the circumferential direction of the polishing head 22 to clean the polishing head 22 until all the polishing head cleaning nozzles on each main body 42 are opened; or

[0093] A3: First open the polishing head cleaning nozzle on one of the main bodies 42 to clean the polishing head. After cleaning for a period of time a, close the polishing head cleaning nozzle, and then open the polishing head cleaning nozzle on another adjacent main body 42 along the rotating direction or the opposite direction of the polishing head to clean the polishing head. After cleaning for a period of time b, close the polishing head cleaning nozzle, and so on in a cycle; where a and b can be equal, or the values of a and b can be selected according to the cleanliness of different regions of the polishing head obtained by the vision sensor. For example, when the polishing head is still rotating at a speed r, when the region with relatively poor cleanliness faces different main bodies 42, the polishing head cleaning nozzles on the corresponding main bodies 42 are opened to clean this region. If the rotation speed of the polishing head is constant, then a = b; if the rotation speed of the polishing head increases, then a < b; if the rotation speed of the polishing head decreases, then a > b.

[0094] Steps A1, A2, and A3 can also be used in combination. For example, first use step A1 and then use step A3; or first use step A1 and then use step A2.

[0095] A1 This method can clean the entire surface of the polishing head 22 in an all-round manner in an instant. Multiple nozzles work simultaneously, so that the cleaning fluid can impact the surface of the polishing head 22 over a large area, quickly removing surface dirt, residual polishing liquid, particles generated by wear and other contaminants. For example, after the polishing process is completed, a large amount of polishing liquid and wafer debris may adhere to the surface of the polishing head. Opening all nozzles at the same time can flush these contaminants from all directions in the shortest time, thereby improving the cleaning efficiency, reducing the cleaning time, and helping to improve the production rhythm of the entire CMP process.

[0096] Since the cleaning is carried out all around at the same time, the cleaning force on the polishing head in all directions is relatively uniform. This is very important for maintaining the shape accuracy and mechanical properties of the polishing head. If the cleaning force is uneven, it may cause local deformation or uneven wear of the polishing head during long-term use. For example, in some high-precision CMP applications, the flatness of the polishing head directly affects the polishing quality of the wafer. Uniform cleaning force can avoid slight changes in the surface of the polishing head caused by the cleaning process, thereby ensuring the uniformity and stability of the wafer polishing and improving the yield of the wafer product.

[0097] The A2 method can clean the polishing head 22 area by area and observe the cleaning effect by opening the nozzles one by one. During the time period when each nozzle is turned on, the pollutant removal in the corresponding area can be checked more carefully, so as to timely find possible cleaning dead corners or dirt accumulation points that are difficult to remove. For example, if the pollutants in a certain area are not effectively removed when a specific nozzle is turned on, the cleaning parameters of the nozzle, such as fluid pressure, flow rate or cleaning liquid composition, can be adjusted in a targeted manner, so as to achieve accurate optimization of the cleaning effect of the entire polishing head. This step-by-step cleaning method is very suitable for some situations with extremely high requirements for cleaning quality, complex polishing head structure or special properties of pollutants. It can ensure that every part of the polishing head can be thoroughly cleaned, improving the quality and reliability of cleaning.

[0098] Compared with opening all nozzles at the same time, opening the nozzles in sequence can avoid the instantaneous high flow and high pressure shock caused by a large number of nozzles working at the same time. This gentler cleaning method puts less pressure on the mechanical structure and pipeline system of the polishing head 22 and the cleaning system, reducing the risk of equipment damage caused by instantaneous impact. At the same time, since not all nozzles are running at the same time, the energy consumption during the cleaning process is relatively low, which helps to reduce the operating cost of the CMP process and improve the service life and stability of the equipment.

[0099] A3 This method forms a dynamic, locally circulating cleaning flow field on the surface of the polishing head. When a nozzle is turned on, the cleaning fluid forms a specific flow pattern in its area of ​​action, flushing and carrying pollutants in the area. When switching to the adjacent nozzle after a time, the new cleaning flow field interacts with the previous flow field, so that the pollutants on the surface of the polishing head are constantly disturbed, transferred and removed. For example, when dealing with some polishing liquid residues with high viscosity or fine particles with strong adsorption force on the surface, this local circulating flow field can gradually weaken the adhesion of pollutants to the surface of the polishing head through multiple flow field switching and superposition, peeling them off the surface and taking them away, thereby improving the cleaning ability of stubborn dirt. In addition, for rotating polishing heads, one area can be cleaned in a targeted and concentrated manner; the duration of a and b can also be adjusted to form circumferential cleaning in sequence.

[0100] Since the nozzles are opened in a cycle one by one, the working time of each nozzle is relatively short and evenly distributed throughout the cleaning cycle. This makes the cleaning time and cleaning effect of each area on the surface of the polishing head relatively balanced, avoiding uneven wear caused by excessive cleaning of one area and insufficient cleaning of other areas. At the same time, during the cleaning process, if a nozzle fails or becomes clogged, it can be more easily located and handled, because only one nozzle is working at a time, and the entire cleaning system will not be disrupted due to the simultaneous failure of multiple nozzles. This improves the maintainability and reliability of the cleaning system, reduces the downtime of the CMP process caused by cleaning system failure, and ensures the continuity of production.

[0101] First, using step A1 can use the simultaneous action of all nozzles at the beginning of cleaning to quickly remove most of the loose contaminants on the surface of the polishing head, quickly start the cleaning process, and improve the initial efficiency of cleaning. Then switch to step A3 to perform deep cleaning on the stubborn dirt that may remain in the A1 method. For example, in the CMP process, there may be large impurities on the surface of the polishing head that are easy to rinse off and dirt that adheres tightly to the surface due to chemical reactions. Step A1 can quickly remove large particles, and step A3 can use the characteristics of its local circulation flow field to gradually remove those stubborn chemical dirt. This combination method not only ensures the cleaning speed, but also improves the thoroughness of cleaning, so that the polishing head can reach a higher cleanliness standard and meet the requirements of high-precision CMP process for the surface quality of the polishing head.

[0102] Although the instantaneous high-flow cleaning in step A1 is highly efficient, it may have a certain impact on the equipment. The relatively gentle and cyclic cleaning method in the subsequent step A3 can provide a certain buffer and protection for the equipment. After quickly removing a large number of pollutants, the use of step A3 allows the equipment to gradually adapt to the cleaning process while performing deep cleaning, reducing the risk of wear and damage to the equipment caused by long-term high-pressure cleaning. This strategy of first efficient and then gentle and deep cleaning, while ensuring the cleaning effect of the polishing head, extends the service life of the cleaning equipment and polishing head, and improves the operating stability and economy of the entire CMP system.

[0103] The comprehensive and simultaneous cleaning of step A1 as a rough cleaning stage can remove a large area of ​​visible contaminants on the surface of the polishing head in the shortest time, covering the entire surface of the polishing head 22, and quickly reducing the overall content of contaminants. Then step A2 is used for fine cleaning, and each area is inspected and cleaned in a targeted manner by opening the nozzles in sequence. For example, after rough cleaning, there may still be some local dirt residues or areas with unsatisfactory cleaning effects. Step A2 can accurately locate and deal with these problems to ensure that each area can achieve the best cleaning effect. This combination method gives full play to the efficiency of step A1 and the accuracy of step A2, improves the overall quality and reliability of cleaning, enables the polishing head to meet the CMP process requirements with extremely high surface cleanliness requirements, and improves the quality and yield of wafer polishing.

[0104] First, use step A1 for comprehensive cleaning. You can preliminarily judge the amount of resources required for the entire cleaning process based on the cleaning effect, such as the amount of cleaning fluid, cleaning time, etc. Then, during the fine cleaning process in step A2, the cleaning parameters of each area can be adjusted in a targeted manner based on the results of the rough cleaning to avoid waste of resources. For example, if it is found that there are fewer pollutants in a certain area after rough cleaning, the cleaning time of the nozzle in that area can be appropriately reduced or the flow rate of the cleaning fluid can be reduced during fine cleaning, thereby improving the utilization efficiency of cleaning resources. At the same time, this comprehensive-first-accurate cleaning process also makes the entire cleaning process more orderly and controllable, which is convenient for operators to monitor and manage, and improves the automation and intelligence level of the cleaning link in the CMP process.

[0105] Optionally, the fluid inlet 432 is divided into a liquid inlet 433 and a gas inlet 434. The liquid inlet 433 is used to communicate with a liquid source, and the gas inlet 434 is used to communicate with a gas source (the gas in the polishing chamber 1 can be used as a gas source for recycling, without increasing additional gas consumption, and without worrying about chemical reaction and corrosion between the gas and the internal components of the polishing chamber). Flow valves 435 are provided between the liquid inlet 433 and the liquid source and between the gas inlet 434 and the gas source.

[0106] In this embodiment, Figure 6As shown, the fluid inlet 432 is divided into a liquid inlet 433 and a gas inlet 434, and a flow valve 435 (specifically, a solenoid valve, a liquid control valve or a gas control valve, etc.) is set. This design brings extremely high precision and intelligence to the cleaning control of the device. Through the flow valve 435 between the liquid inlet 433 and the liquid source, the liquid flow entering the fluid channel 43 can be accurately adjusted. For example, when it is necessary to accurately control the liquid ratio in the gas-liquid mixture, the flow valve 435 can accurately adjust the flow rate and flow of the liquid according to the preset ratio parameters to ensure that the liquid content in the mixture meets the requirements. Similarly, the flow valve 435 between the gas inlet 434 and the gas source also plays a key role in the control of the gas flow. In some cleaning scenarios that require specific gas pressure or flow, such as using high-pressure gas to impact some difficult-to-remove dirt, the flow valve 435 can accurately adjust the gas flow to the required level. The setting of this flow valve 435 enables the device to flexibly adjust the flow of liquid and gas according to different cleaning process requirements, pollution degree, surface material and other factors. The operator can adjust the opening of the flow valve 435 remotely or locally through a preset program or according to the cleaning effect feedback monitored in real time, thereby realizing precise control over the entire cleaning process. This not only improves the controllability and repeatability of the cleaning process and ensures the consistency of the cleaning effect each time, but also helps to improve the stability of the CMP process and the stability of product quality, and reduce wafer processing defects and process fluctuations caused by human operation errors or unstable cleaning processes.

[0107] like Figure 7 As shown, the fluid channel 43 is configured as a branch channel 1 436 and a branch channel 2 437. The branch channel 1 436 is connected to the first nozzle 411 and the second nozzle 412. The branch channel 2 437 is connected to the fourth nozzle 414. Figure 8 A reserved hole 441 is provided on the branch channel 1 436, and the reserved hole 441 is blocked with a plug. When the reserved hole 441 needs to be activated, the plug in the reserved hole 441 can be removed (after the reserved hole 441 is activated, a nozzle can be installed or other pipes can be connected, etc.), which improves the adaptability of the branch channel 1 436. The operator can choose whether to remove the plug according to the actual cleaning needs. Figure 8 The branch channel 1 436 is also provided with a mounting hole 440 for mounting a regulating valve 438. Fig. 9 The branch channel 437 is also provided with a mounting hole 440 for mounting a regulating valve 438. Fig.10 As shown, the regulating valve 438 is provided with a through opening. When the regulating valve 438 is rotated to a position as shown in FIG. Fig.10 When the regulating valve 438 is in the position shown, the regulating valve 438 is open and the through opening allows fluid to pass through the branch channel 1 436. Fig.11When in the position shown, the regulating valve 438 is closed and the through opening does not allow fluid to pass through the branch channel 1 436. Fig.12 As shown, a limiting surface 439 is provided on the surface of the main body. Correspondingly, a matching clamp is provided on the outer surface of the regulating valve 438, which can be clamped on the corresponding limiting surface 439 after the regulating valve 438 is rotated, so as to achieve a limiting effect and prevent the position from being inaccurate when the regulating valve 438 is rotated, resulting in failure to achieve the desired on or off state. Similarly, the branch channel 2 437 is provided with the same structure as the branch channel 1 436. By controlling the opening and closing degree of the regulating valve 438, it is possible to specifically adjust whether the nozzle located on the branch channel 1 436 or the branch channel 2 437 sprays the cleaning fluid and the flow rate of the sprayed cleaning fluid. At the same time, when the regulating valve 438 is in a closed state, the corresponding nozzle can be replaced or maintained.

[0108] According to another embodiment of the present invention, a cleaning method for a CMP polishing chamber is provided, using the above-mentioned cleaning device. Fig.13 , the cleaning method comprises the following steps:

[0109] S1: The nozzle 41 sprays fluid to clean the surface 3 of the polishing unit.

[0110] Optionally, in step S1 , the nozzle 41 first sprays out the gas-liquid mixture, then sprays out the liquid, and finally sprays out the gas.

[0111] In this embodiment, the specific order of fluid spraying from the nozzle 41 is first the gas-liquid mixture, then the liquid, and finally the gas. This specific order is carefully determined based on the characteristics of the contaminants on the surface of the CMP chamber and reducing the consumption of the cleaning liquid while improving the cleaning effect.

[0112] In the initial stage, the gas-liquid mixture can utilize the impact and stirring of the gas and the dissolution and penetration ability of the liquid to preliminarily decompose and peel off various dirt on the surface, creating favorable conditions for the subsequent cleaning steps. After the gas-liquid mixture acts, although some dirt on the surface has been removed, some fine particles, impurities dissolved in the liquid, and bubbles may still remain. At this time, the sprayed liquid can completely wash away these remaining dirt and stains with its large flow rate and good fluidity, ensuring that the cleanliness of the surface reaches a higher level. The gas sprayed at last can quickly blow off the droplets on the surface to prevent the formation of water stains. This sequential setting makes the cleaning process form a logically rigorous and interlocking system, which can not only comprehensively and efficiently clean a variety of common pollutants on the surface of the CMP chamber, significantly improve the cleanliness, but also reduce the consumption of cleaning liquid (the gas can use the gas in the polishing chamber 1 to form a cycle, which will not increase the cost of gas production), reduce costs, and reduce the amount of sewage generated.

[0113] Optionally, in step S1 , the time for the nozzle 41 to spray the gas-liquid mixture is controlled to be longer than the time for spraying the liquid; the time for the nozzle 41 to spray the gas-liquid mixture is controlled to be longer than the time for spraying the gas.

[0114] In this embodiment, the spraying time of different fluids is controlled so that the cleaning time of the gas-liquid mixture is relatively long. This is an optimized design made by fully considering the unique role and importance of the gas-liquid mixture in the entire cleaning process. The gas-liquid mixture has an irreplaceable advantage in treating the complex dirt structure on the surface of the CMP chamber. It can simultaneously exert the physical impact of the gas and the chemical dissolution of the liquid. For some stubborn dirt layers, such as the polishing liquid residue accumulated for a long time, the dirt formed by chemical reaction with the surface, etc., it takes a long time to fully decompose and remove them. For example, for some hard dirt shells formed by the reaction with metal ions on the surface of the polishing pad, the gas-liquid mixture may need to act continuously to effectively break and dissolve them. The cleaning time of liquid and gas is relatively short because after the gas-liquid mixture completes the main decontamination work, the liquid is mainly used for the final flushing and replenishment to ensure that there are no residual dirt particles, dissolved impurities or bubble stains, and the time required is relatively short. The drying effect of the gas is more rapid, and the droplets on the surface can be basically removed quickly. Such time control can not only ensure the thoroughness of the cleaning effect, but also improve the cleaning efficiency and shorten the entire cleaning cycle, thereby improving the utilization rate of CMP equipment and increasing the processing output of wafers, thus improving production benefits while ensuring product quality.

[0115] Optionally, in step S1 , the volume ratio of gas to liquid in the gas-liquid mixture sprayed from the nozzle 41 is controlled to be less than one third.

[0116] In this embodiment, in the gas-liquid mixture, the liquid component plays a core role in dissolving and flushing dirt. The pollutants on the surface of the CMP chamber are mostly solid particles, residual chemicals, and a mixture of dirt formed by their combination. These pollutants require the dissolving ability and strong flushing force of the liquid to be effectively removed from the surface. If the gas ratio is too high, the gas-liquid mixture will become too "thin", and the dissolving and flushing effects of the liquid will be greatly reduced, and the pollutants cannot be effectively carried away from the surface. Controlling the volume ratio of gas to liquid to less than one-third can ensure that the liquid occupies a dominant position in the mixture, giving it a strong dissolving and flushing ability to cope with the large number of solid particles, residual chemicals and other pollutants that may exist on the surface of the CMP chamber, ensuring that the gas-liquid mixture can effectively remove and carry away pollutants from the surface, thereby improving the cleaning effect and cleaning quality.

[0117] Optionally, in step S1 , when the nozzle 41 is controlled to spray the gas-liquid mixture, the volume ratio of gas to liquid gradually decreases.

[0118] In this embodiment, the volume ratio of gas to liquid is gradually reduced during the spraying process of the gas-liquid mixture. This dynamic ratio change is designed to better adapt to the changing situation that the dirt is gradually reduced and the surface is gradually cleaned during the cleaning process. In the early stage of cleaning, the surface dirt is relatively serious and the structure is complex. A relatively large gas ratio can play its powerful disturbance and impact role. For example, a higher proportion of gas can make the gas-liquid mixture produce a stronger "explosion" effect when it contacts the surface, quickly loosen and break the large area of ​​dirt layer, and create good conditions for the penetration and dissolution of the liquid. As the cleaning proceeds, the dirt is gradually removed and the cleanliness of the surface gradually improves. At this time, more liquid is needed for fine flushing and dissolving the residual tiny dirt particles. Gradually reducing the gas ratio and increasing the liquid ratio can gradually change the cleaning ability of the mixture to dissolution and fine flushing. For example, in the later stage of cleaning, when most of the dirt has been removed and only some fine particles and slight chemical residues are left, a higher proportion of liquid can dissolve and flush these residues more accurately, ensuring that the surface reaches a very high degree of cleanliness. This dynamically changing proportional control can further optimize the cleaning effect, improve the thoroughness and uniformity of cleaning, make the cleaning process more intelligent and refined, meet the strict requirements of the CMP process on the cleanliness of the chamber surface, and provide ideal surface conditions for high-quality wafer polishing.

[0119] The cleaning method also includes the following steps:

[0120] S2: transferring the wafer to the wafer loading cup 21 in the polishing chamber 1;

[0121] S3: the polishing head 22 picks up the wafer and moves the wafer onto the polishing pad to perform chemical mechanical polishing. During the process of the polishing head 22 picking up the wafer and moving the wafer onto the polishing pad and / or performing chemical mechanical polishing on the wafer, the wafer loading cup cleaning nozzle sprays fluid to clean the surface of the wafer loading cup 21;

[0122] S4: the wafer loading cup cleaning nozzle stops cleaning the wafer loading cup 21, the wafer chemical mechanical polishing is finished, the polishing head 22 carries the wafer and moves to the wafer loading cup 21, while the polishing head 22 carries the wafer and moves to the wafer loading cup 21, the polishing head cleaning nozzle sprays fluid to clean the surface of the polishing head 22;

[0123] S5: The wafer is transferred out of the polishing chamber 1, and the polishing head cleaning nozzle sprays fluid to clean the surface of the polishing head 22;

[0124] S6: Repeat S2 to S5.

[0125] In this embodiment, the coordinated process of the cleaning method and the wafer transfer, polishing and other steps in the CMP process achieves a seamless connection between the cleaning and CMP processes, and constructs an efficient, stable and highly automated wafer processing system.

[0126] In S2 , the wafer is placed on the wafer loading cup 21 , which establishes an accurate starting point for subsequent operations.

[0127] In S3, when the polishing head 22 picks up and moves the wafer to the polishing pad and / or performs chemical mechanical polishing, the wafer loading cup cleaning nozzle cleans the surface of the loading cup 21. This operation can timely remove the tiny particles from the wafer, residual polishing liquid or environmental impurities that may be contaminated on the wafer loading cup 21, prevent them from contaminating new wafers in subsequent cycles, and maintain the overall cleanliness of the polishing chamber, reduce wafer surface defects caused by contamination, and improve the yield and quality stability of wafer processing.

[0128] In S4, after polishing is completed, the polishing head 22 carries the wafer back to the wafer loading cup 21, and the polishing head cleaning nozzle cleans the surface of the polishing head 22. At this time, the surface of the polishing head 22 is covered with residual substances generated during the polishing process, such as polishing liquid, wafer grinding chips and chemical reaction products. Timely cleaning can prevent these residues from solidifying on the surface of the polishing head, reduce the difficulty of subsequent cleaning, and keep the polishing head in good working condition, thereby ensuring the uniformity and accuracy of the pressure applied to the wafer during the next polishing operation, and stabilizing the polishing effect of the wafer.

[0129] In S5, after the wafer is transferred out of the polishing chamber 1, the surface of the polishing head 22 is cleaned again, which allows more time to thoroughly remove all kinds of dirt remaining before, further ensuring the reliability and stability of the performance of the polishing head 22. This helps to extend the service life of the polishing head 22, reduce wear and corrosion caused by contamination, and provide consistent polishing conditions for the processing of the next batch of wafers, avoiding process fluctuations caused by different degrees of contamination of the polishing head 22, and ensuring the consistency and repeatability of the quality of different batches of wafer products.

[0130] S2-S5 are repeated continuously to build an efficient and stable CMP process cycle. This timely cleaning takes advantage of the fact that the polishing liquid and other stains stay on the surface of the wafer loading cup 21 or the surface of the polishing head 22 for a short time and have low firmness, and achieves a better cleaning effect with lower cleaning fluid consumption, and can effectively reduce the damage to the wafer loading cup 21 and the polishing head 22 caused by strong cleaning.

[0131] Optionally, in step S4, the polishing head cleaning nozzle sprays fluid to briefly clean the surface of the polishing head 22, and the cleaning time is 2 seconds.

[0132] In this embodiment, after the wafer polishing is completed, the polishing head 22 carries the wafer and moves to the wafer loading cup 21. During this process, the polishing head cleaning nozzle will spray fluid to briefly clean the surface of the polishing head 22, and the cleaning time is 2s. After the polishing is completed, the surface of the polishing head 22 is most likely to be attached with a large amount of residues, which include polishing liquid, material particles worn from the surface of the wafer during the polishing process, and products produced by possible chemical reactions. If these residues are not processed in time, they will gradually dry and solidify on the surface of the polishing head, thereby increasing the difficulty of subsequent cleaning, and may even cause permanent damage to the surface of the polishing head, affecting the service life and performance of the polishing head. While the wafer is placed back into the wafer loading cup, this short cleaning of 2s is performed. Although the time is not long, it can quickly remove a part of the contaminants that have just formed and have not yet completely solidified, creating very favorable conditions for a more thorough and comprehensive cleaning of the polishing head after the wafer is transferred out of the polishing chamber. This helps to maintain the polishing head 22 in an initial clean state after each use, thereby ensuring that the pressure applied by the polishing head 22 to the wafer can be accurately controlled when the wafer is picked up for polishing next time, so that the pressure is evenly distributed on the wafer surface, thereby stabilizing the polishing quality of the wafer and reducing problems such as inconsistent wafer surface flatness, local over-polishing or under-polishing caused by surface contamination of the polishing head 22.

[0133] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A cleaning device for a CMP polishing chamber, wherein the polishing chamber (1) contains a polishing unit (2), wherein the polishing unit (2) comprises a wafer loading cup (21) and a polishing head (22); characterized in that: The cleaning device comprises: A nozzle (41) is located in the polishing chamber (1), and the nozzle (41) includes a wafer loading cup cleaning nozzle and a polishing head cleaning nozzle, which are respectively used to spray fluid to clean the wafer loading cup (21) and the polishing head (22), and the fluid sprayed by the nozzle (41) is liquid and / or gas and / or a gas-liquid mixture.

2. The cleaning device for a CMP polishing chamber according to claim 1, characterized in that: The polishing head (22) has an upper surface (221) and a side surface (222); The polishing head cleaning nozzle comprises a first nozzle (411) and a second nozzle (412), wherein the first nozzle (411) and the second nozzle (412) are both located on one side of the polishing head (22), the first nozzle (411) is used for cleaning the upper surface (221), and the second nozzle (412) is used for cleaning the side surface (222).

3. The cleaning device for a CMP polishing chamber according to claim 2, characterized in that: The first nozzle (411) is used for spraying a fan-shaped fluid; the second nozzle (412) is used for spraying a cone-shaped fluid.

4. The cleaning device for a CMP polishing chamber according to claim 2, characterized in that: The wafer loading cup cleaning nozzle comprises a fourth nozzle (414), wherein the fourth nozzle (414) is arranged on one side of the wafer loading cup (21), and the fourth nozzle (414) is used for cleaning the upper surface of the wafer loading cup (21).

5. The cleaning device for a CMP polishing chamber according to any one of claims 1 to 4, characterized in that: The nozzle (41) is used to spray out the gas-liquid mixture, liquid and gas in sequence.

6. The cleaning device for a CMP polishing chamber according to claim 5, characterized in that: The ratio of gas to liquid in the gas-liquid mixture sprayed out by the nozzle (41) is adjustable.

7. The cleaning device for a CMP polishing chamber according to claim 1, characterized in that: Also includes: A main body (42) is arranged in the polishing chamber (1), the main body (42) has a fluid channel (43), the fluid channel (43) has a fluid outlet (431) and a fluid inlet (432), the nozzle (41) is arranged on the main body (42), and the inlet of the nozzle (41) is connected to the fluid outlet (431).

8. The cleaning device for a CMP polishing chamber according to claim 7, characterized in that: The fluid inlet (432) includes a liquid inlet (433) and a gas inlet (434), wherein the liquid inlet (433) is used to communicate with a liquid source, and the gas inlet (434) is used to communicate with a gas source; A flow valve (435) is provided between the liquid inlet (433) and the liquid source and between the gas inlet (434) and the gas source.

9. A method for cleaning a CMP polishing chamber, using the cleaning device according to any one of claims 1 to 8, characterized in that: The cleaning method comprises the following steps: S1: controlling the nozzle (41) to spray fluid to clean the surface of the polishing unit (2); S2: transferring the wafer to a wafer loading cup (21) in the polishing chamber (1); S3: the polishing head (22) picks up the wafer and moves the wafer onto the polishing pad to perform chemical mechanical polishing. During the process of the polishing head (22) picking up the wafer and moving the wafer onto the polishing pad and / or during the process of performing chemical mechanical polishing on the wafer, the wafer loading cup cleaning nozzle sprays fluid to clean the surface of the wafer loading cup (21); S4: the wafer loading cup cleaning nozzle stops cleaning the wafer loading cup (21), the wafer chemical mechanical polishing is finished, the polishing head (22) carries the wafer and moves it onto the wafer loading cup (21), and while the polishing head (22) carries the wafer and moves it onto the wafer loading cup (21), the polishing head cleaning nozzle sprays fluid to clean the surface of the polishing head (22); S5: The polished wafer exits the polishing chamber (1), and the fluid is ejected from the polishing head cleaning nozzle to clean the surface of the polishing head (22). S6: Repeat S2 - S5.

10. The cleaning method for a CMP polishing chamber according to claim 9, characterized in that: The nozzle (41) first ejects a gas - liquid mixture, then ejects liquid, and finally ejects gas.

11. The cleaning method for a CMP polishing chamber according to claim 9, characterized in that: A plurality of the main bodies (42) are arranged around the polishing head (22). When cleaning the polishing head (22), the cleaning is performed according to any one of the following steps: A1: Simultaneously open the polishing head cleaning nozzles on the plurality of the main bodies (42) around the polishing head (22) to clean the polishing head (22). A2: Sequentially open the polishing head cleaning nozzles on each of the main bodies (42) along the circumferential direction of the polishing head (22) to clean the polishing head (22) until all the polishing head cleaning nozzles on each of the main bodies (42) are opened. A3: Open the polishing head cleaning nozzle on one of the main bodies (42) to clean the polishing head (22). After cleaning for a period of time a, close the polishing head cleaning nozzle. Then open the polishing head cleaning nozzle on another main body (42) adjacent to it in the rotating direction or the opposite direction of the polishing head (22) to clean the polishing head (22). After cleaning for a time b, close the polishing head cleaning nozzle. And so on in a cycle. Any sequential combination of A1, A2, and A3.

12. The cleaning method for a CMP polishing chamber according to claim 11, characterized in that: In step A3, a = b.

13. The cleaning method for a CMP polishing chamber according to claim 11, characterized in that: In step A3, when the polishing head rotates, the polishing head cleaning nozzles on the plurality of main bodies (42) are sequentially opened to clean the same area of the polishing head.

14. The cleaning method for a CMP polishing chamber according to claim 13, characterized in that: If the rotation speed of the polishing head is constant, then a = b; if the rotation speed of the polishing head increases, then a < b; if the rotation speed of the polishing head decreases, then a > b.

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