Chemical mechanical polishing apparatus, liquid supply system, and liquid supply method

Abstract

The application provides a chemical mechanical polishing device, a liquid supply system and a liquid supply method, and belongs to the field of wafer polishing devices. The chemical mechanical polishing device, the liquid supply system and the liquid supply method comprise: a polishing disc, wherein a polishing pad is arranged on the polishing disc; a slurry conveying arm is suspended above the polishing pad, and a fluid channel is arranged in the slurry conveying arm; a nozzle is arranged on the slurry conveying arm, the liquid inlet end of the nozzle is communicated with the fluid channel, and the liquid outlet end of the nozzle faces the polishing pad; an elastic sealing sleeve is arranged in the fluid channel, a cavity is formed in the elastic sealing sleeve, the free end of the elastic sealing sleeve can be elastically deformed to abut against or be away from the liquid inlet end, so as to block or open the connection between the nozzle and the fluid channel; the instantaneous drop stopping of the nozzle is realized through the elasticity of the elastic sealing sleeve itself, and the concentration fluctuation of the polishing liquid is avoided.

Description

Technical Field

[0001] This application belongs to the technical field of wafer polishing equipment, and more specifically, relates to a chemical mechanical polishing device, a liquid supply system, and a liquid supply method. Background Technology

[0002] Chemical mechanical polishing (CMP) is a device that achieves global planarization of wafers. The wafer is inverted and placed face down on the polishing head, and the polishing pad is placed on a rotating platform. When the polishing process begins, the wafer and the polishing pad rotate in opposite directions at a certain speed. The polishing head applies downward pressure, and the polishing slurry is sprayed onto the polishing pad. The chemical components of the polishing slurry react with the wafer surface material, softening the target material. The softened material is then removed by the mechanical force generated by the relative motion, ultimately achieving atomic-level planarity on the wafer surface.

[0003] In the above process, the uniformity of the polishing slurry directly affects the polishing uniformity and wafer yield: on the one hand, whether the concentration and distribution of the polishing slurry on the surface of the polishing pad are uniform directly determines the uniformity of the removal rate in each area of ​​the wafer; on the other hand, the introduction of additional liquid will change the local concentration of the polishing slurry on the surface of the polishing pad, causing local dilution, which in turn destroys the polishing uniformity and introduces batch-to-batch process fluctuations. Summary of the Invention

[0004] In view of the above problems, this application provides a chemical mechanical polishing device, a liquid supply system and a liquid supply method, thereby solving or at least alleviating one or more of the above-mentioned problems and other problems existing in the prior art.

[0005] A chemical mechanical polishing apparatus, comprising: A polishing disc, on which a polishing pad is provided; A slurry delivery arm is suspended above the polishing pad, and a fluid channel is provided inside the slurry delivery arm; A nozzle is provided on the slurry conveying arm, with the inlet end of the nozzle communicating with the fluid channel and the outlet end facing the polishing pad; An elastic sealing sleeve is disposed within the fluid channel. A cavity is formed within the elastic sealing sleeve. The free end of the elastic sealing sleeve can elastically deform to abut against or move away from the inlet end, thereby blocking or opening the connection between the nozzle and the fluid channel. After pressurized fluid is introduced into the fluid channel, the free end is compressed and contracts inward to open the inlet end. The fluid in the fluid channel enters through the inlet end and is ejected from the outlet end. The cavity has a first volume and is connected to the fluid channel and filled with fluid. After the pressure in the fluid channel decreases, the elastic sealing sleeve can return to its original position by its own elasticity and abut against the liquid inlet end, preventing the fluid from continuing to enter the nozzle. At the same time, the cavity volume increases from the first volume to the second volume, generating a back suction force. Under the action of the back suction force and the surface tension of the liquid, the liquid remaining in the nozzle stays in the nozzle, avoiding affecting the concentration distribution of the polishing liquid on the surface of the polishing pad.

[0006] As a further technical solution, the chemical mechanical polishing equipment also includes: A fixed seat is provided on the slurry conveying arm, and one end of the fixed seat extends into the fluid channel. The elastic sealing sleeve is provided on the fixed seat to prevent the elastic sealing sleeve from moving under the action of fluid pressure, and the fixed seat can block one end of the elastic sealing sleeve.

[0007] As a further technical solution, the elastic sealing sleeve has an installation part and a deformable part connected to the bottom of the installation part, and the bottom of the deformable part has the free end; The deformable part is conical, and its outer diameter decreases from the mounting part to the free end. When the deformable part is subjected to radial water pressure in the fluid channel, it contracts radially and moves axially away from the nozzle to increase the flow area of ​​the fluid entering the nozzle.

[0008] As a further technical solution, the inner wall of the mounting part has a retaining ring, and the outer wall of the fixing seat has a retaining groove that is adapted to the retaining ring. The retaining ring and the retaining groove can restrict the movement of the mounting part.

[0009] As a further technical solution, the nozzle has a plurality of nozzles, which are distributed radially at intervals along the polishing pad. All of the nozzles are connected to the fluid channel. The number of elastic sealing sleeves corresponds one-to-one with the number of nozzles. After the external fluid pressure decreases, the elastic sealing sleeves independently block the liquid inlet end of the corresponding nozzle to avoid cross-contamination and dripping.

[0010] As a further technical solution, the elastic sealing sleeve is integrally molded from silicone material.

[0011] A wafer chemical mechanical polishing (CMP) fluid supply system for supplying fluid to the CMP equipment, comprising: A liquid supply pipeline is connected to the fluid channel, and the liquid supply pipeline is equipped with a liquid supply valve and a liquid supply pump; The controller is electrically connected to both the liquid supply valve and the liquid supply pump. The controller is configured to: control the liquid supply valve to open so that the liquid supply pump supplies liquid into the fluid channel; after the elastic sealing sleeve is subjected to radial pressure, the free end is separated from the liquid inlet end face of the nozzle so that the fluid is sprayed onto the polishing pad through the nozzle. The controller is also configured to: control the liquid supply valve to close, the pressure in the fluid channel gradually decreases as the nozzle continues to discharge liquid, thereby causing the elastic sealing sleeve to return to its original position by its own elasticity and fit against the end face of the free end to form a seal, and causing the nozzle to stop spraying liquid.

[0012] As a further technical solution, the controller is also configured to, before controlling the liquid supply valve to close, first control the liquid supply pipeline to reduce the pressure of the fluid channel to a preset low pressure threshold in a step-down manner, and then close the liquid supply valve, so as to avoid continuously pushing liquid out of the nozzle during the reset process of the elastic sealing sleeve after the liquid supply valve is closed, thereby improving the instantaneous stop effect.

[0013] A method for supplying a chemical mechanical polishing (CMP) solution to a wafer, utilizing the aforementioned CMP solution supply system, includes the following steps: S100, control the liquid supply pump and the liquid supply valve to open, and supply liquid to the fluid channel through the liquid supply pipeline; S200, several of the elastic sealing sleeves are simultaneously subjected to radial liquid pressure and contract to deform, so that liquid is ejected from the nozzle; S300, after the polishing pad is cleaned, the liquid supply pump and the liquid supply valve are closed simultaneously; S400, the elastic sealing sleeve returns to its original position against the inlet end of the nozzle by its own elasticity, thereby cutting off the liquid supply to the nozzle.

[0014] As a further technical solution, in S300, before the polishing pad cleaning is completed, the liquid supply pump and the liquid supply valve are controlled to close in advance, and the advance time is t.

[0015] As a further technical solution, the flow area of ​​the liquid supply pipeline is set to A, the liquid flow velocity in the liquid supply pipeline is set to V, the number of nozzles is set to N, the volume change of the cavity during liquid supply and under natural conditions is set to ΔT, and the advance time of closing of the liquid supply pump and the liquid supply valve is set to t=(N·ΔT) / (A·V).

[0016] The beneficial effects of this application embodiment are as follows: the elastic sealing sleeve is set in the fluid channel of the slurry conveying arm, and its free end directly abuts the liquid inlet end of the nozzle, blocking the connection between the fluid channel and the nozzle from the source position of the water inlet end of the nozzle; after the liquid supply pressure disappears, the elastic sealing sleeve instantly resets and seals the liquid inlet end by its own elasticity, and the residual liquid in the fluid channel cannot continue to enter the nozzle. At the same time, the cavity volume of the elastic sealing sleeve increases to form a micro negative pressure cavity. The small amount of liquid remaining in the nozzle is stably kept in the nozzle under the action of the micro negative pressure cavity and the surface tension of the liquid, realizing instantaneous stopping of dripping and near-zero leakage. This completely eliminates the problem of residual liquid dripping irregularly and slowly from the nozzle after the valve is closed, as is the case in existing technologies. It avoids excessive liquid on the polishing pad and dilution of the polishing solution in some areas due to additional dripping, thus keeping the concentration and distribution of the polishing solution on the surface of the polishing pad stable. On the one hand, the uniformity of the removal rate in each area of ​​the wafer is guaranteed, and the uniformity of the film thickness on the wafer surface is significantly improved. On the other hand, it eliminates the additional process variables introduced by the uncontrollable amount of dripping, avoids film thickness fluctuations between wafers in a box and film thickness drift between batches, significantly improves the stability and batch consistency of the film thickness on the wafer polishing surface, and improves the wafer yield. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the overall wafer chemical mechanical polishing apparatus; Figure 2 A schematic cross-sectional view of the slurry conveying arm; Figure 3 for Figure 2 Enlarged structural diagram at point A in the middle; Figure 4 This is a schematic diagram of the elastic sealing sleeve under compressed and contracted state. Figure 5 This is a schematic diagram of the elastic sealing sleeve in its reset state. Figure 6 Schematic diagram of the fixed seat and elastic sealing sleeve structure; Figure 7 This is a cross-sectional view of another embodiment of the mounting base within the slurry conveying arm; Figure 8 This is a schematic diagram of another embodiment of the elastic sealing sleeve and nozzle; Figure 9 A schematic diagram showing the thickness of the silicon dioxide film in a box of wafers under random and stable non-drip conditions; Figure 10 A schematic diagram showing the thickness of the copper film in a box of wafers under random and stable non-drip conditions; Figure label: In the diagram: 100, polishing disc; 110, polishing pad; 200, slurry delivery arm; 210, fluid channel; 220, polishing slurry outlet; 300, nozzle; 310, inlet end; 320, outlet end; 400, elastic sealing sleeve; 401, cavity; 410, mounting part; 411, retaining ring; 420, deformable part; 421, free end; 500, fixed seat; 501, slot; 600, supply pipeline; 610, supply valve; 620, supply pump; 700, dressing tool; 800, polishing head. Detailed Implementation To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments in the specific implementation of this application should fall within the protection scope of the embodiments of this application.

[0019] To keep the drawings concise, each drawing only schematically shows the parts relevant to the disclosure; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0020] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0021] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the liquid level of the first feature is higher than that of the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the liquid level of the first feature is lower than that of the second feature.

[0022] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] It should be understood that, unless the context clearly states otherwise, the terms "comprising," "including," or "having" as used herein refer to the presence of an element, but do not exclude the presence or addition of one or more other elements. Furthermore, "comprising" and / or "including" as used herein specify the presence of shapes, numbers, steps, operations, members, elements, and / or combinations thereof, and do not exclude the presence or addition of one or more other shapes, numbers, operations, elements, and / or combinations thereof. Some embodiments of this application are described in detail below with reference to the accompanying drawings. Where there is no conflict between the embodiments, the following embodiments and features can be combined with each other. The steps in the following method embodiments are for illustrative purposes only and are not intended to limit this application.

[0025] First, the effect of irregular droplets on the thickness of the polished wafer surface film is explained. In the chemical mechanical polishing process, the polishing head 800 draws in the wafer and presses it against the polishing pad 110, which rotates with the polishing disk 100. The slurry delivery arm 200 delivers polishing slurry to the surface of the polishing pad 110 through the polishing slurry outlet 220. The chemical composition of the polishing slurry reacts with the wafer surface material to soften the target material. The softened material is removed by the mechanical force generated by the relative motion. The removal rate of the wafer is directly related to the concentration of polishing slurry on the surface of the polishing pad 110. After the supply valve is closed, the residual liquid between the nozzle and the supply line will drip slowly and irregularly from the nozzle opening under the influence of gravity. The timing, location, and amount of dripping are uncontrollable. The dripping liquid dilutes the polishing slurry in local areas of the polishing pad 110, reducing its concentration. When the wafer passes through this area, the chemical softening effect weakens, and the removal rate decreases accordingly, resulting in insufficient material removal on the wafer surface in some areas. Since the dripping occurs randomly, the dilution of the polishing slurry experienced by different wafers in the same wafer cask varies. This ultimately results in increased fluctuations in the finished film thickness of each wafer in a cask, with the average film thickness deviating from the target value (insufficient removal causes the film thickness to be too thick), and poor consistency in film thickness between different batches. In addition, the extra dripping liquid also changes the local lubrication state of the polishing pad 110, further exacerbating the non-uniformity of the removal rate.

[0026] like Figure 1 As shown, the chemical mechanical polishing (CMP) apparatus of this application embodiment includes a polishing disc 100, a slurry delivery arm 200, a nozzle 300, and an elastic sealing sleeve 400. The polishing disc 100 is a rotatable platform, and a polishing pad 110 is laid on the upper surface of the polishing disc 100 and fixed by adhesive backing. The polishing head 800 is suspended above the polishing pad 110 and can be raised, lowered, and rotated, used to back-suction the wafer and press the wafer against the polishing pad 110. The dresser 700 is disposed above the polishing pad 110 and is used to dress the surface of the polishing pad 110 during the polishing process or between polishing intervals. The slurry conveying arm 200 is suspended above the polishing pad 110. Its root is mounted on the frame of the equipment via a rotating shaft and is driven by a motor to swing, so that the slurry conveying arm 200 can rotate between the liquid supply position above the polishing pad 110 and the clearance position outside the polishing pad 110. A fluid channel 210 is provided inside the slurry conveying arm 200. One end of the fluid channel 210 is connected to the liquid supply source via the liquid supply pipeline 600. The slurry conveying arm 200 is also provided with an independent pipeline connected to the polishing liquid outlet 220 for conveying polishing liquid to the polishing liquid outlet 220.

[0027] like Figure 2 and Figure 3As shown, there are several nozzles 300, which are arranged radially at intervals on the slurry conveying arm 200 along the polishing pad 110. Specifically, the slurry conveying arm 200 is provided with several nozzle seats, and the nozzles 300 are screwed into the corresponding nozzle seats and fixed by screwing. The liquid inlet end 310 of the nozzle 300 is connected to the fluid channel 210, and the liquid outlet end 320 faces the polishing pad 110, which is used to spray liquid onto the polishing pad 110 to rinse away the residual impurities on the polishing pad 110.

[0028] like Figure 3 , Figure 4 , Figure 6 As shown, the elastic sealing sleeves 400 are disposed within the fluid channel 210, and their number corresponds one-to-one with the number of nozzles 300. Each elastic sealing sleeve 400 has a mounting portion 410 and a deformable portion 420 connected to the bottom of the mounting portion 410. The mounting portion 410 is a cylindrical sleeve, preferably with a wall thickness of 1 mm. The deformable portion 420 is conical, and its outer diameter decreases from the mounting portion 410 towards the free end 421 at the bottom of the deformable portion 420. In its natural state, the cone angle of the deformable portion 420 is approximately 25°, and its wall thickness is uniformly approximately 1 mm. The end face of the free end 421 has rounded corners. A cavity 401 is formed within the elastic sealing sleeve 400. Figure 4 In the liquid supply conduction state shown, after pressurized fluid is introduced into the fluid channel 210, the pressurized fluid acts radially on the outer wall of the deformable part 420. The deformable part 420 is compressed and contracts radially inward and moves axially away from the nozzle 300. The free end 421 disengages from the end face of the liquid inlet end 310 to open the liquid inlet end 310. The fluid enters the nozzle 300 through the liquid inlet end 310 and is ejected from the liquid outlet end 320. Due to the conical structure of the deformable part 420, compared with the cylindrical structure, the annular gap formed between the free end 421 and the liquid inlet end 310 after contraction increases the flow area of ​​the fluid entering the nozzle 300. At this time, the volume of the cavity 401 is the first container and is connected to the fluid channel 210. The gas originally present in the cavity 401 is squeezed out by the fluid or dissolved in the fluid and discharged. At this time, the cavity 401 is filled with fluid.

[0029] like Figure 5As shown, after the liquid supply valve is closed, the pressure in the fluid channel 210 decreases, and the liquid remaining in the nozzle 300 continues to flow out from the outlet end 320 under the action of gravity, while the fluid in the fluid channel 210 is continuously replenished. When the fluid pressure in the fluid channel 210 is insufficient to maintain the deformation of the deformable part 420, the deformable part 420 gradually returns to its original position under its own elastic action. During the resetting process, on the one hand, the liquid in the fluid channel 210 can flow to the nozzle 300, thereby causing the fluid pressure in the fluid channel 210 to continue to decrease until the free end 421 returns to its original position and abuts against the end face of the inlet end 310. The rounded corner of the end face of the free end 421 ensures that it is completely and tightly fitted with the end face of the inlet end 310 to form a surface seal, preventing the fluid from continuing to enter the nozzle 300. At this time, the fluid in the fluid channel 210 is blocked because both the inlet and outlet sides are blocked, so the fluid in the fluid channel 210... The fluid is in a static state. During the deformation and reset process of the deformable part 420, the volume of the cavity 401 gradually increases to the second volume. Since the liquid outlet 320 of the nozzle 300 is in the open state, no fluid will be added to the upper cavity 401 against gravity. As a result, the liquid in the cavity 401 is insufficient to fill the cavity 401, forming a micro-negative pressure cavity with back suction. The micro-negative pressure cavity has a back suction effect on the small amount of liquid remaining in the nozzle 300. Under the combined action of the micro-negative pressure cavity and the surface tension of the liquid, the liquid remaining in the nozzle 300 remains stably in the nozzle 300 and will not drip from the liquid outlet 320, achieving almost instantaneous drip cessation. The sealing position of the elastic sealing sleeve 400 is close to the liquid inlet 310 of the nozzle 300, which is a source shutdown. The cavity section between the elastic sealing sleeve 400 and the liquid outlet 320 where residual liquid is retained is very short, storing very little liquid. Relying on the liquid tension and the effect of the micro-negative pressure cavity, the liquid can be stably retained in the nozzle 300.

[0030] like Figure 5As shown, the system also includes several fixed seats 500, each mounted on the slurry conveying arm 200 with one end extending into the fluid channel 210. Specifically, the fixed seats 500 and the nozzles 300 on the slurry conveying arm 200 are located on opposite sides of the fluid channel 210, with a gap between them. Elastic sealing sleeves 400 are located within the gap between the fixed seats 500 and the nozzles 300. The fixed seats 500 are threadedly tightened to the nozzle seats on the slurry conveying arm 200, and leakage can be prevented between the fixed seats 500 and the slurry conveying arm 200 by installing sealing rings. Several elastic sealing sleeves 400 are correspondingly mounted on several fixed seats 500. Specifically, each elastic sealing sleeve 400 includes a mounting portion 410 and a deformable portion 420. The inner wall of the mounting portion 410 has a retaining ring 411, which is a cylindrical ring protruding towards the center. Correspondingly, the outer wall of the fixed seat 500 has a retaining groove 501 adapted to the retaining ring 411. The mounting part 410 is elastically fitted onto the fixed base 500. The retaining ring 411 is embedded in the retaining groove 501 and fits tightly with the retaining groove 501. This not only restricts the movement of the mounting part 410, but also uses the fluid pressure in the fluid channel 210 to press the mounting part 410 against the outer wall of the fixed base 500, thereby preventing the mounting part 410 from falling off the fixed base 500.

[0031] refer to Figure 7 , Figure 8 As an optional solution, another embodiment of the fixing seat 500 can be configured as a single strip structure with a positioning protrusion integrally formed at the bottom. The positioning protrusion extends into the fluid channel 210, and the elastic sealing sleeve 400 is fitted on the positioning protrusion.

[0032] In addition to the arrangement where the elastic sealing sleeve 400 corresponds one-to-one with the nozzle 300, a scheme in which two or more nozzles 300 share a single elastic sealing sleeve 400 can also be selected. In this scheme, the liquid inlet end 310 of two or more nozzles 300 is located in the same section of common pipeline. This common pipeline is equipped with an independent liquid inlet, and the liquid inlet is connected to the fluid channel 210. The elastic sealing sleeve 400 is located at the liquid inlet and, through its own elastic deformation, blocks or opens the liquid inlet of the common pipeline, thereby realizing the synchronous opening or closing of all nozzles 300 connected to the same common pipeline.

[0033] Optionally, the elastic sealing sleeve 400 is integrally molded from a corrosion-resistant, swelling-resistant, highly elastic silicone material.

[0034] Furthermore, after the external fluid pressure decreases, several elastic sealing sleeves 400 independently block the liquid inlet end 310 of the corresponding nozzle 300, and the liquid between each nozzle 300 no longer flows through and connects, thus avoiding the problem of liquid cross-flow and dripping caused by the mutual flow of liquid.

[0035] The wafer chemical mechanical polishing liquid supply system of this application embodiment includes a liquid supply pipeline 600 and a controller. The liquid supply pipeline 600 is connected to the fluid channel 210. The liquid supply pipeline 600 is provided with a liquid supply valve 610 and a liquid supply pump 620. The controller is electrically connected to the liquid supply valve 610 and the liquid supply pump 620 respectively. The controller can be a PLC or an industrial computer. The liquid supply valve 610 can be a solenoid valve or a pneumatic valve. The liquid supply pump 620 can be a diaphragm pump or a peristaltic pump. During liquid supply, the controller controls the liquid supply valve 610 to open so that the liquid supply pump 620 supplies liquid into the fluid channel 210. After the elastic sealing sleeve 400 bears radial pressure, the free end 421 disengages from the liquid inlet end 310 end face of the nozzle 300, so that the fluid is sprayed onto the polishing pad 110 through the nozzle 300. When the liquid supply stops, the controller controls the liquid supply valve 610 to close. The pressure in the fluid channel 210 gradually decreases as the nozzle 300 continues to discharge liquid, thereby causing the elastic sealing sleeve 400 to return to its original position by its own elasticity and fit the free end 421 against the liquid inlet end 310 end face to form a seal, and the nozzle 300 stops spraying liquid. Furthermore, the controller is configured to, before closing the supply valve 610, first control the supply line 600 to reduce the pressure in the fluid channel 210 to a preset low-pressure threshold in a stepped pressure reduction manner (e.g., by adjusting the speed of the supply pump 620 in stages or by opening and closing the bypass valve in stages), and then close the supply valve 610. This prevents the elastic sealing sleeve 400 from continuously pushing liquid out of the nozzle 300 during the reset process after the supply valve 610 is closed, thereby improving the instantaneous stop effect. The preset low-pressure threshold is less than the minimum pressure required to deform the deformable part 420.

[0036] The following describes the complete working process of the wafer chemical mechanical polishing liquid supply method of this application: S100, the liquid supply pump 620 and the liquid supply valve 610 are opened, and liquid is supplied to the fluid channel 210 through the liquid supply pipeline 600; S200, several elastic sealing sleeves 400 are simultaneously subjected to radial liquid pressure and contract and deform, so that liquid is sprayed out from the nozzle 300 to rinse the polishing pad 110; S300, after the polishing pad 110 is cleaned, the liquid supply pump 620 and the liquid supply valve 610 are closed simultaneously; S400, the elastic sealing sleeves 400 rely on their own elasticity to return to the liquid inlet end 310 of the nozzle 300 to cut off the liquid supply of the nozzle 300.

[0037] Furthermore, in S300, before the polishing pad 110 is cleaned, the liquid supply pump 620 and the liquid supply valve 610 are closed in advance by a time t. Since the volume of the cavity 401 increases when the elastic sealing sleeve 400 is reset, and some liquid needs to be replenished from the fluid channel 210, closing it in advance can make the pressure in the fluid channel 210 drop first by continuously draining liquid from the nozzle 300, thus avoiding the liquid being pushed out of the nozzle 300 during reset. Let A be the flow area of ​​the liquid supply line 600, V be the liquid velocity within the liquid supply line 600, N be the number of nozzles 300, and ΔT be the volume change of the cavity 401 during liquid supply and in its natural state. Then, the advance time for closing the liquid supply pump 620 and the liquid supply valve 610 is t = (N·ΔT) / (A·V). Where N·ΔT is the total volume of liquid replenished when all elastic sealing sleeves 400 reset, and A·V is the volume of liquid discharged per unit time from the liquid supply line 600. Dividing these two values ​​gives the time required for the pressure to drop until the reset is complete. Closing the line ahead of time ensures that the reset process of the elastic sealing sleeves 400 matches the pressure relief process of the pipeline, further improving the instantaneous stop effect. It should be noted that ΔT can be calibrated by measuring the volume change of the cavity 401 of the elastic sealing sleeves 400 in both the liquid supply and natural states, while A and V can be determined by the specifications of the liquid supply line 600 and the flow meter reading.

[0038] Furthermore, to ensure that the interpolation ΔT between the first and second volumes is at a nearly definite value, a conical thin wall is added to the bottom of the fixing base 500. This conical thin wall retains the cavity 401 and can also conform to the outer wall of the conical thin wall after the deformable part 420 is deformed under pressure. This allows the deformable part 420 to remain in a nearly definite position both in its natural state (without fluid pressure or with insufficient fluid pressure to deform) and after deformation. The advance closing time is then calculated based on the difference ΔT between the first and second volumes.

[0039] The following is combined with Figure 9 and Figure 10 This paper demonstrates the improvement effect of eliminating irregular droplets on the surface film thickness of polished wafers. A box of 24 wafers was used in the experiment, and polishing was performed on both existing equipment with random droplets and equipment using the instantaneous stop mechanism of this application. The finished film thickness of each wafer after polishing was measured. Figure 7 As shown, for silicon dioxide films, under random droplet conditions, the film thickness of each wafer deviates from the target value and exhibits significant inter-wafer fluctuations (average film thickness approximately 4900 Å, inter-wafer range approximately 400 Å), while under the stable non-droplet conditions of this application, the average film thickness is approximately 5000 Å and the inter-wafer range is approximately 100 Å; Figure 8As shown, for copper films, the average film thickness is approximately 3950 angstroms and the inter-wafer range is approximately 500 angstroms under random droplet conditions, while the average film thickness is approximately 4030 angstroms and the inter-wafer range is approximately 150 angstroms under stable, non-droplet conditions. It is evident that random dropleting significantly increases the inter-wafer variation in the finished wafer film.

[0040] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A chemical mechanical polishing device, characterized in that, include: A polishing disc, on which a polishing pad is provided; A slurry conveying arm is suspended above the polishing pad, and a fluid channel is provided inside the slurry conveying arm; A nozzle is provided on the slurry conveying arm, with the inlet end of the nozzle communicating with the fluid channel and the outlet end facing the polishing pad; An elastic sealing sleeve is disposed within the fluid channel. A cavity is formed within the elastic sealing sleeve. The free end of the elastic sealing sleeve can elastically deform to abut against or move away from the inlet end, thereby blocking or opening the connection between the nozzle and the fluid channel. After pressurized fluid is introduced into the fluid channel, the free end is compressed and contracts inward to open the inlet end. The fluid in the fluid channel enters through the inlet end and is ejected from the outlet end. The cavity has a first volume and is connected to the fluid channel and filled with fluid. After the pressure in the fluid channel decreases, the elastic sealing sleeve can return to its original position by its own elasticity and abut against the liquid inlet end, preventing the fluid from continuing to enter the nozzle. At the same time, the cavity volume increases from the first volume to the second volume, generating a back suction force. Under the action of the back suction force and the surface tension of the liquid, the liquid remaining in the nozzle stays in the nozzle, avoiding affecting the concentration distribution of the polishing liquid on the surface of the polishing pad.

2. The chemical mechanical polishing equipment according to claim 1, characterized in that, The chemical mechanical polishing equipment also includes: A fixed seat is provided on the slurry conveying arm, and one end of the fixed seat extends into the fluid channel. The elastic sealing sleeve is provided on the fixed seat to prevent the elastic sealing sleeve from moving under the action of fluid pressure, and the fixed seat can block one end of the elastic sealing sleeve.

3. The chemical mechanical polishing equipment according to claim 2, characterized in that, The elastic sealing sleeve has a mounting portion and a deformable portion connected to the bottom of the mounting portion, the bottom of the deformable portion having the free end; The deformable part is conical, and its outer diameter decreases from the mounting part to the free end. When the deformable part is subjected to radial water pressure in the fluid channel, it contracts radially and moves axially away from the nozzle to increase the flow area of ​​the fluid entering the nozzle.

4. The chemical mechanical polishing equipment according to claim 3, characterized in that, The inner wall of the mounting part has a retaining ring, and the outer wall of the fixing seat has a retaining groove that is adapted to the retaining ring. The retaining ring and the retaining groove can restrict the movement of the mounting part.

5. The chemical mechanical polishing equipment according to claim 1, characterized in that, The nozzles are of several kinds, and the nozzles are distributed radially at intervals along the polishing pad. All the nozzles are connected to the fluid channel. The number of elastic sealing sleeves corresponds one-to-one with the number of nozzles. After the external fluid pressure decreases, the elastic sealing sleeves independently block the liquid inlet end of the corresponding nozzle to avoid cross-contamination and dripping.

6. The chemical mechanical polishing equipment according to claim 1, characterized in that, The elastic sealing sleeve is integrally molded from silicone material.

7. A wafer chemical mechanical polishing fluid supply system for supplying fluid to the chemical mechanical polishing equipment according to any one of claims 1 to 6, characterized in that, include: A liquid supply pipeline is connected to the fluid channel, and the liquid supply pipeline is equipped with a liquid supply valve and a liquid supply pump; The controller is electrically connected to both the liquid supply valve and the liquid supply pump. The controller is configured to: control the liquid supply valve to open so that the liquid supply pump supplies liquid into the fluid channel; after the elastic sealing sleeve is subjected to radial pressure, the free end is separated from the liquid inlet end face of the nozzle so that the fluid is sprayed onto the polishing pad through the nozzle. The controller is also configured to: control the liquid supply valve to close, the pressure in the fluid channel gradually decreases as the nozzle continues to discharge liquid, thereby causing the elastic sealing sleeve to return to its original position by its own elasticity and fit against the end face of the free end to form a seal, and causing the nozzle to stop spraying liquid.

8. The wafer chemical mechanical polishing solution supply system according to claim 7, characterized in that, The controller is also configured to, before controlling the liquid supply valve to close, first control the liquid supply pipeline to reduce the pressure of the fluid channel to a preset low pressure threshold in a step-down manner, and then close the liquid supply valve, so as to avoid continuously pushing liquid out of the nozzle during the reset process of the elastic sealing sleeve after the liquid supply valve is closed, thereby improving the instantaneous stop effect.

9. A method for supplying a chemical mechanical polishing (CMP) solution to a wafer, comprising supplying the solution using the CMP solution supply system of claim 7, characterized in that, Includes the following steps: S100, control the liquid supply pump and the liquid supply valve to open, and supply liquid to the fluid channel through the liquid supply pipeline; S200, several of the elastic sealing sleeves are simultaneously subjected to radial liquid pressure and contract to deform, so that liquid is ejected from the nozzle; S300, after the polishing pad is cleaned, the liquid supply pump and the liquid supply valve are closed simultaneously; S400, the elastic sealing sleeve returns to its original position against the inlet end of the nozzle by its own elasticity, thereby cutting off the liquid supply to the nozzle.

10. The wafer chemical mechanical polishing solution supply method according to claim 9, characterized in that, In S300, before the polishing pad cleaning is completed, the liquid supply pump and the liquid supply valve are controlled to close in advance, and the advance time is t.

11. The wafer chemical mechanical polishing solution supply method according to claim 10, characterized in that, Let the flow area of ​​the liquid supply pipeline be A, the liquid flow velocity in the liquid supply pipeline be V, the number of nozzles be N, the volume change of the cavity during liquid supply and under natural conditions be ΔT, and the advance time for the liquid supply pump and the liquid supply valve to close be t = (N·ΔT) / (A·V).

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