Chemical mechanical polishing system and method

Abstract

The invention provides a chemical mechanical polishing system and method. The system comprises a flattening module and a cleaning module, wherein the flattening module and the cleaning module are arranged in parallel; the planarization module comprises at least one planarization unit, and the planarization unit is used for grinding the fed wafer; the cleaning module comprises a rolling brush cleaning unit, a surface modification unit and a single-piece cleaning unit which are arranged in sequence; the rolling brush cleaning unit is used for carrying out physical cleaning and chemical cleaning on the ground wafer; the surface modification unit is used for performing plasma bombardment on the surface of the cleaned wafer so as to generate hydrophilic functional groups on the surface of the wafer; and the single wafer cleaning unit is used for cleaning and drying the modified wafer. According to the invention, the hydrophobic surface of the wafer after CMP can be effectively cleaned and dried, the cleaning and drying efficiency is improved, and the surface defects of the wafer are reduced.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a chemical mechanical polishing system and method. Background Art

[0002] In the semiconductor manufacturing process, chemical mechanical polishing (CMP) is a key surface flattening technology that is widely used to remove excess material layers on the wafer surface. After the CMP process, polishing liquid, abrasive particles and other pollutants usually remain on the wafer surface. These pollutants may affect the surface quality of the wafer and need to be removed promptly and thoroughly to avoid adverse effects on subsequent processes. Therefore, the cleaning and drying process after CMP is crucial.

[0003] During the cleaning process, deionized water or other chemical cleaning solutions need to be evenly spread on the wafer surface to effectively remove polishing liquid and particulate matter. However, in some cases, the wafer surface exhibits hydrophobicity, that is, the surface is not easily wetted by water. The hydrophobic surface will cause the cleaning solution to not evenly cover the entire surface, resulting in unsatisfactory cleaning results and inability to completely remove contaminants. In addition, water droplets are easily formed on the hydrophobic surface, which are difficult to completely remove during the subsequent drying process, resulting in residual water stains or surface defects, affecting the wafer yield. Summary of the invention

[0004] The embodiments of the present application provide a chemical mechanical polishing system and method to effectively clean and dry the hydrophobic surface of a wafer after CMP, improve the cleaning and drying efficiency, and reduce wafer surface defects.

[0005] In a first aspect, an embodiment of the present application provides a chemical mechanical polishing system, comprising a planarization module and a cleaning module; wherein the planarization module and the cleaning module are arranged in parallel;

[0006] The planarization module includes at least one planarization unit, and the planarization unit is used to grind the wafer fed in;

[0007] The cleaning module includes a roller brush cleaning unit, a surface modification unit and a single wafer cleaning unit arranged in sequence; the roller brush cleaning unit is used to physically and chemically clean the ground wafer; the surface modification unit is used to plasma bombard the surface of the cleaned wafer to generate hydrophilic functional groups on the wafer surface; the single wafer cleaning unit is used to clean and dry the modified wafer.

[0008] In a possible implementation, the surface modification unit includes a box, a vacuum device, a wafer carrier, a suction device and a plasma device;

[0009] A sealing gate is provided on the side of the box;

[0010] The vacuum device is arranged on the outer side of the box body and is connected with the interior of the box body through a vacuum pipe;

[0011] The wafer carrying platform is fixed to the bottom of the box; a placement groove is provided on the wafer carrying platform, and a plurality of through holes arranged in a ring are provided at the bottom of the placement groove; wherein the placement groove is used to carry the wafer;

[0012] The suction device is arranged below the wafer carrier and is connected to the placement groove through the plurality of through holes; the suction device is also connected to an exhaust gas pipeline running through the bottom of the box body, and is used to discharge redundant materials in the modification process through the exhaust gas pipeline;

[0013] The plasma device is fixed on the top of the box body and communicated with the interior of the box body through a plasma nozzle; wherein the mouth of the plasma nozzle corresponds to the placement groove.

[0014] In a possible implementation, a positioning piece is provided at the center of the bottom surface of the placement groove;

[0015] A guide ring is also provided on the side of the placement groove, and the guide ring is used to limit the wafer.

[0016] In a possible implementation, the single-wafer cleaning unit includes a cleaning chamber, a two-fluid cleaning device, a deionized water cleaning device, a drying device, and a stage;

[0017] The stage is fixed to the bottom of the cleaning chamber and is used to carry the wafer;

[0018] The two-fluid cleaning device comprises a first fixed rod and a first nozzle; the first fixed rod is fixed to the bottom of the cleaning chamber; the first nozzle is rotatably connected to the first fixed rod; wherein the rotation radius of the first nozzle is the horizontal distance between the first fixed rod and the center of the stage;

[0019] The deionized water cleaning device comprises a second fixed rod and a second nozzle; the second fixed rod is fixed to the bottom of the cleaning chamber, and the second nozzle is rotatably connected to the second fixed rod; wherein the rotation radius of the second nozzle is the horizontal distance between the second fixed rod and the center of the stage;

[0020] The drying device includes a third fixed rod, an IPA nozzle and a nitrogen nozzle; the third fixed rod is fixed to the bottom of the cleaning chamber, and the IPA nozzle and the nitrogen nozzle are both rotatably connected to the third fixed rod; wherein the rotation radius of the IPA nozzle and the nitrogen nozzle is the horizontal distance between the third fixed rod and the center of the stage.

[0021] In a possible implementation, the stage includes a rotating platform, a splash shield, and a plurality of claws, and the single-wafer cleaning unit also includes a waste discharge device;

[0022] The rotating platform is used to place and rotate the wafer;

[0023] The plurality of claws are arranged on the rotating platform and are used to fix the wafer;

[0024] The splash shield is arranged on the outer side of the rotating platform;

[0025] The waste discharge device is arranged at the bottom of the cleaning cavity and is located between the rotating machine table and the splash shield.

[0026] In a possible implementation, the single-chip cleaning unit further includes a fan filter device;

[0027] The fan filter device is arranged above the cleaning cavity and is used for filtering particles in the air and maintaining the pressure in the cleaning cavity.

[0028] In a possible implementation, the chemical mechanical polishing system further includes a wafer transfer module for moving the wafer between the planarization unit, the roller brush cleaning unit, the surface modification unit, and the single wafer cleaning unit.

[0029] In a possible implementation, the film transfer module includes a first manipulator, a second manipulator, a third manipulator, a fourth manipulator, and a fifth manipulator;

[0030] The first robot is used to obtain wafers to be processed and to deliver processed wafers;

[0031] The second robot is arranged between the planarization module and the cleaning module, and is used to receive the wafer to be processed from the first robot and send it to the planarization unit, and to take out the processed wafer from the single-wafer cleaning unit and transfer it to the first robot;

[0032] The third robot is arranged between the planarization module and the cleaning module, and is used to take out the wafer from the planarization unit and send it into the roller brush cleaning unit;

[0033] The fourth robot is disposed between the roller brush cleaning unit and the surface modification unit, and is used to take out the wafer from the roller brush cleaning unit and send it into the surface modification unit;

[0034] The fifth robot is arranged between the surface modification unit and the single-wafer cleaning unit, and is used for taking out the wafer from the surface modification unit and sending it into the single-wafer cleaning unit.

[0035] In a second aspect, an embodiment of the present application provides a chemical mechanical polishing method, which is applied to the system described in the first aspect or any possible implementation of the first aspect, the method comprising:

[0036] Sending a first wafer to be processed into a planarization unit;

[0037] Controlling the planarization unit to grind the first wafer to obtain a second wafer;

[0038] transferring the second wafer to a roller brush cleaning unit;

[0039] Controlling the roller brush cleaning unit to perform physical cleaning and chemical cleaning on the second wafer to obtain a third wafer;

[0040] transferring the third wafer to a surface modification unit;

[0041] controlling the surface modification unit to perform plasma bombardment on the third wafer to obtain a fourth wafer;

[0042] Transferring the fourth wafer to a single wafer cleaning unit;

[0043] The single wafer cleaning unit is controlled to clean and dry the fourth wafer to obtain a fifth wafer.

[0044] The single-wafer cleaning unit comprises a cleaning chamber, a two-fluid cleaning device, a deionized water cleaning device, a drying device and a stage;

[0045] The controlling the single-wafer cleaning unit to clean and dry the fourth wafer to obtain a fifth wafer comprises:

[0046] Controlling the rotating table in the stage to rotate so as to rotate the fourth wafer on the rotating table;

[0047] Controlling the two-fluid cleaning device and the deionized water cleaning device to clean the fourth wafer in sequence, so as to form a deionized water film on the surface of the fourth wafer;

[0048] Controlling the IPA nozzle and the nitrogen nozzle in the drying device to rotate around the third fixed rod, and rotating the IPA nozzle to above the center of the rotating machine table;

[0049] Controlling the IPA nozzle to spray the isopropyl alcohol solution onto the center of the rotating table to replace the deionized water film on the fourth wafer with the isopropyl alcohol liquid film;

[0050] reducing the flow rate of the isopropyl alcohol solution sprayed from the IPA nozzle;

[0051] The nitrogen nozzle is controlled to spray nitrogen, and the IPA nozzle and the nitrogen nozzle are controlled to rotate around the third fixed rod, so that the nitrogen nozzle passes through the center of the rotary table and rotates to the edge of the rotary table to dry the fourth wafer to obtain a fifth wafer.

[0052] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0053] The embodiment of the present application sets a surface modification unit in the cleaning module of the chemical polishing system, and can modify the surface of the cleaned wafer by plasma bombardment, generate hydrophilic functional groups on the wafer surface, so as to modify the hydrophobic surface of the wafer into hydrophilic, enhance the wettability of the cleaning liquid, ensure that the cleaning liquid can evenly cover the wafer surface, so as to completely remove residual pollutants and particulate matter; and, a single-wafer cleaning unit is set after the surface modification unit, and the single-wafer cleaning unit can be used to clean and dry the modified wafer. Since the surface of the wafer is changed to hydrophilic, water droplets on the wafer surface can be reduced, the residual water droplets and the generation of surface defects can be reduced, and the wafer yield can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1 is a schematic structural diagram of a chemical mechanical polishing system provided in an embodiment of the present application;

[0056] Figure 2 is a schematic diagram of the structure of the surface modification unit provided in the embodiments of the present application;

[0057] Figure 3 is a schematic structural diagram of a single-wafer cleaning unit provided in an embodiment of the present application;

[0058] Figure 4 This is a flow chart of a chemical mechanical polishing method provided in an embodiment of the present application;

[0059] Among them, 1- loading and unloading port, 2- film transfer module, 3- flattening unit, 4- roller brush cleaning unit, 5- surface modification unit, 6- single-wafer cleaning unit;

[0060] 21-first manipulator, 22-second manipulator, 23-third manipulator, 24-fourth manipulator, 25-fifth manipulator;

[0061] 51-box, 52-vacuum device, 53-wafer carrier, 531-placement groove, 532-through hole, 533-positioning piece, 534-guide ring; 54-suction device, 55-plasma device, 56-sealing gate, 57-exhaust pipe, 58-plasma nozzle;

[0062] 61-cleaning chamber, 62-two-fluid cleaning device, 621-first fixed rod, 622-first nozzle; 63-deionized water cleaning device, 631-second fixed rod, 632-second nozzle; 64-drying device, 641-third fixed rod, 642-IPA nozzle, 643-nitrogen nozzle; 65-stage, 651-rotating table, 652-splash cover, 653-multiple claws; 66-waste discharge device, 67-fan filter device. DETAILED DESCRIPTION

[0063] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0064] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0065] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0066] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0067] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0068] In addition, the “plurality” mentioned in the embodiments of the present application should be interpreted as two or more.

[0069] The inventors have found that in order to clean and dry the flattened wafer, the wafer surface is usually cleaned with a cleaning liquid, but it is difficult for the cleaning liquid to evenly cover the hydrophobic surface, resulting in difficulty in completely removing contaminants; and there will be water droplets remaining on the hydrophobic surface, resulting in poor drying effect and easy generation of water spots or defects. Therefore, it is necessary to consider the cleaning and drying process of wafers with hydrophobic surfaces.

[0070] In order to effectively clean and dry the hydrophobic surface of the wafer after CMP, in an embodiment of the present application, a surface modification unit is provided in the cleaning module of the chemical mechanical polishing system, and the surface of the cleaned wafer is plasma bombarded by the surface modification unit to change the hydrophobic surface into a hydrophilic surface. The modified wafer is then cleaned and dried by a single-wafer cleaning unit, which can reduce water droplets on the wafer surface, reduce water droplet residue and the generation of surface defects.

[0071] In order to make the purpose, technical solutions and advantages of the present application clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0072] Figure 1 The structural schematic diagram of the chemical mechanical polishing system provided in the embodiment of the present application is shown, and the details are as follows:

[0073] like Figure 1 As shown, the chemical mechanical polishing system includes a planarization module and a cleaning module; wherein the planarization module and the cleaning module are arranged in parallel.

[0074] The planarization module includes at least one planarization unit 3, which is used to grind the wafer fed in. Here, the planarization unit 3 can be specifically set according to the needs of chemical mechanical polishing of the wafer, such as the number of grinding times and grinding pressure, etc. The number of planarization units 3 can be selected according to the grinding and cleaning time to ensure the efficiency of the entire planarization process.

[0075] The cleaning module includes a roller brush cleaning unit 4, a surface modification unit 5 and a single wafer cleaning unit 6 which are arranged in sequence; the roller brush cleaning unit 4 is used for physically and chemically cleaning the ground wafer; the surface modification unit 5 is used for plasma bombarding the surface of the cleaned wafer to produce hydrophilic functional groups on the wafer surface; the single wafer cleaning unit 6 is used for cleaning and drying the modified wafer.

[0076] In this embodiment, the ground wafer is first cleaned by the roller brush cleaning unit 4 to remove larger particles and impurities on the wafer surface. The roller brush cleaning unit 4 can be equipped with a high-speed rotating brush to perform physical and chemical cleaning on the ground wafer in combination with a cleaning liquid.

[0077] The surface modification unit 5 can perform plasma bombardment on the surface of the cleaned wafer under a vacuum environment to generate hydrophilic functional groups on the surface of the wafer to improve the hydrophilicity of the surface of the wafer.

[0078] After the wafer surface is treated, the hydrophilic surface of the wafer is finally cleaned and dried by the single-wafer cleaning unit 6, so that the cleaning liquid can be distributed more evenly on the wafer surface, the cleaning effect is improved, and the water droplets on the wafer surface are reduced, thereby reducing the residual water droplets and the generation of surface defects.

[0079] In this embodiment, by adding a surface modification unit 5 between the roller brush cleaning unit 4 and the single-wafer cleaning unit 6, the surface modification unit 5 can be used to improve the activity of the hydrophobic wafer surface, increase polar functional groups, and make water and cleaning agents better wet the surface, forming a more uniform liquid film, thereby achieving a more ideal cleaning effect. At the same time, improving the hydrophilicity of the wafer surface can reduce drying residues during the drying process, achieving a more efficient and thorough cleaning effect.

[0080] In addition, since the surface modification unit 4 for plasma treatment is added to the overall process of chemical mechanical polishing, it does not need to be performed independently outside the production line, which can increase the integration of the system, reduce the space occupied by the equipment, and reduce the complexity of the process chain.

[0081] In some embodiments, the chemical mechanical polishing system further includes a wafer transfer module 2 for moving the wafer between the planarization unit 3 , the roller brush cleaning unit 4 , the surface modification unit 5 and the single wafer cleaning unit 6 .

[0082] Here, the wafer can be transferred through the wafer transfer module 2 to move the wafer between the various units. The wafer transfer module 2 may include a robot, a conveyor belt, a conveyor plate, and the like.

[0083] Optional, such as Figure 1 As shown, the wafer transfer module 2 of this embodiment includes a first robot 21, a second robot 22, a third robot 23, a fourth robot 24 and a fifth robot 25, and the wafers can be transferred at different positions through each robot.

[0084] The first robot 21 is used to obtain wafers to be processed and to deliver processed wafers.

[0085] The second robot 22 is disposed between the planarization module and the cleaning module, and is used to receive the wafer to be processed from the first robot 21 and send it to the planarization unit 3 , and to take out the processed wafer from the single-wafer cleaning unit 6 and transfer it to the first robot 21 .

[0086] Among them, the second robot 22 is mainly used to send the wafers to be processed into the flattening unit, and grab the dried wafers from the single-wafer cleaning unit 6, that is, the second robot 22 does not contact pollutants throughout the process. At the same time, the first robot 21 can receive the wafers to be processed from the outside, and transport the processed wafers back to the outside. In addition, the first robot 21 mainly interacts with the second robot 22, so the first robot 21 will not contact pollutants throughout the process, which can ensure dry in and dry out, and ensure the cleanliness of the wafer.

[0087] The third robot 23 is disposed between the planarization module and the cleaning module, and is used to take out the wafer from the planarization unit 3 and send it into the roller brush cleaning unit 4 .

[0088] The fourth robot 24 is disposed between the roller brush cleaning unit 4 and the surface modification unit 5 , and is used for taking out the wafer from the roller brush cleaning unit 4 and sending it into the surface modification unit 5 .

[0089] The fifth robot 25 is disposed between the surface modification unit 5 and the single-wafer cleaning unit 6 , and is used for taking out the wafer from the surface modification unit 5 and sending it into the single-wafer cleaning unit 6 .

[0090] The embodiment of the present application sets a surface modification unit in the cleaning module of the chemical polishing system, and can modify the surface of the cleaned wafer by plasma bombardment, generate hydrophilic functional groups on the wafer surface, so as to modify the hydrophobic surface of the wafer into hydrophilic, enhance the wettability of the cleaning liquid, ensure that the cleaning liquid can evenly cover the wafer surface, so as to completely remove residual pollutants and particulate matter; and, a single-wafer cleaning unit is set after the surface modification unit, and the single-wafer cleaning unit can be used to clean and dry the modified wafer. Since the surface of the wafer is changed to hydrophilic, water droplets on the wafer surface can be reduced, the residual water droplets and the generation of surface defects can be reduced, and the wafer yield can be improved.

[0091] In some embodiments, Figure 1 As shown, the chemical mechanical polishing system also includes a loading and unloading platform, which may include a plurality of loading and unloading ports 1, and the loading and unloading ports 1 are used to carry wafers to be processed and processed wafers, so that the first robot 21 can obtain the wafers to be processed and send out the processed wafers.

[0092] In this embodiment, a plurality of loading and unloading ports 1 may be provided, each loading and unloading port 1 may hold a wafer, and the first robot may grab the wafers to be processed from each loading and unloading port 1 and place the processed wafers in turn according to a preset order. The loading and unloading ports 1 may also be divided, where some of the loading and unloading ports 1 may be used to place the wafers to be processed, and the remaining loading and unloading ports are used to place the processed wafers, thereby realizing the distinction between wafers of different processes.

[0093] In some embodiments, Figure 2 As shown in the structural schematic diagram of the surface modification unit, the surface modification unit 5 includes a box 51, a vacuum device 52, a wafer carrier 53, a suction device 54 and a plasma device 55.

[0094] A sealing gate 56 is provided on the side of the box 51. When the sealing gate 56 is opened, a wafer can be placed into the surface modification unit 5 or a wafer can be grabbed from the surface modification unit 5 by a robot. Before plasma bombardment, the sealing gate can be closed to form a vacuum environment in the box 51.

[0095] The vacuum device 52 is disposed on the outer side of the box 51 and communicates with the interior of the box 51 through a vacuum pipe. The vacuum device 52 can evacuate the box 51 through the vacuum pipe to form a vacuum environment in the box 51 for subsequent plasma bombardment.

[0096] The wafer carrier 53 is fixed to the bottom of the box 51; a placement groove 531 is provided on the wafer carrier 53, and a plurality of through holes 532 arranged in a ring are provided at the bottom of the placement groove 531; wherein the placement groove 531 is used to carry the wafer. The placement groove 531 is a groove on the wafer carrier 53, which can carry the wafer so as to accurately perform plasma bombardment on the surface of the wafer.

[0097] Here, the wafer carrier 53 may include two parts with different radii, wherein the radius of the upper part is larger than that of the lower part, a placement groove 531 is provided on the upper surface of the upper part, and the lower part is used to be fixed and connected to the bottom of the box body 51.

[0098] Optionally, the wafer carrying platform 53 can be fixed at the center of the bottom of the box body 51 .

[0099] The suction device 54 is disposed below the wafer carrier 53 and is connected to the placement groove 531 through a plurality of through holes 532. The suction device 54 can suck the redundant materials generated during the plasma bombardment through the through holes 532 to prevent the redundant materials from staying on the wafer surface so as to effectively bombard the wafer surface with plasma. The suction device 54 is also connected to the exhaust pipe 57 that runs through the bottom of the box 51 to discharge the redundant materials during the modification process through the exhaust pipe 57.

[0100] The plasma device 55 is fixed above the box 51 and is connected to the interior of the box 51 through the plasma nozzle 58; wherein the mouth of the plasma nozzle 58 corresponds to the placement groove 531, so that the mouth of the plasma nozzle 58 corresponds to the surface of the wafer, achieving uniform modification of the wafer surface.

[0101] In this embodiment, plasma treatment is generally performed by introducing gas into a vacuum chamber and applying an electric field to ionize the gas. Taking oxygen plasma as an example, oxygen is excited to generate oxygen free radicals (O·) and oxygen ions (O 2 -). When these oxygen radicals or oxygen ions in the plasma react with the wafer surface, hydroxyl (-OH) groups are generated. Hydroxyl (-OH) has strong hydrophilicity. This hydrogen bonding allows the material surface to be in close contact with water molecules, thus showing hydrophilicity. On the untreated surface, due to the presence of organic pollutants or inert chemical groups, the contact angle of water is 100°±30°, which can be improved to 20°±15° after treatment.

[0102] Here, when modifying the wafer surface, the power of the plasma device 55 can be 100W to 1000W, the flow rate of the plasma nozzle 58 can range from 100ml / min to 500ml / min, and the vacuum pressure in the box 51 can range from 0.1Pa to 10Pa.

[0103] Optional, such as Figure 2 As shown, a positioning member 533 is disposed at the center of the bottom surface of the placement groove 531 ; a guide ring 534 is also disposed on the side surface of the placement groove 531 , and the guide ring 534 is used to limit the wafer.

[0104] In this embodiment, the center of the placement groove can be clearly determined by the positioning member 533 so as to accurately position the wafer and ensure that the wafer is placed in the correct position. The guide ring 534 can be used to restrict the wafer and improve the stability of the wafer modification process.

[0105] In some embodiments, see Figure 3 The structural schematic diagram of the single-wafer cleaning unit shown in the figure, the single-wafer cleaning unit 6 includes a cleaning chamber 61, a two-fluid cleaning device 62, a deionized water cleaning device 63, a drying device 64 and a stage 65.

[0106] The stage 65 is fixed at the bottom of the cleaning chamber 61 and is used to carry the wafer.

[0107] The two-fluid cleaning device 62 includes a first fixed rod 621 and a first nozzle 622; the first fixed rod 621 is fixed at the bottom of the cleaning chamber 61; the first nozzle 622 is rotatably connected to the first fixed rod 621; wherein the rotation radius of the first nozzle 622 is the horizontal distance between the first fixed rod 621 and the center of the stage 65.

[0108] Here, the first nozzle 622 of the two-fluid cleaning device 62 can rotate around the first fixing rod 621 and move to the top of the wafer, so as to spray the cleaning liquid to the wafer for cleaning. After the cleaning liquid is sprayed, the first nozzle 622 can be reset to avoid affecting the movement of the deionized water cleaning device 63, the drying device 64 and the wafer.

[0109] The deionized water cleaning device 63 includes a second fixed rod 631 and a second nozzle 632; the second fixed rod 631 is fixed at the bottom of the cleaning chamber 61, and the second nozzle 632 is rotatably connected to the second fixed rod 631; wherein the rotation radius of the second nozzle 632 is the horizontal distance between the second fixed rod 631 and the center of the stage 65.

[0110] Here, the second nozzle 632 of the deionized water cleaning device 63 can rotate around the second fixing rod 631 and move to the top of the wafer, so as to spray deionized water to the wafer to rinse the surface of the wafer. After the deionized water is sprayed, the second nozzle 632 can be reset to avoid affecting the movement of the two-fluid cleaning device 62, the drying device 64 and the wafer.

[0111] The drying device 64 includes a third fixed rod 641, an IPA (isopropyl alcohol) nozzle 642 and a nitrogen nozzle 643; the third fixed rod 641 is fixed to the bottom of the cleaning chamber 61, and the IPA nozzle 642 and the nitrogen nozzle 643 are both rotatably connected to the third fixed rod 641; wherein the rotation radius of the IPA nozzle 642 and the nitrogen nozzle 643 is the horizontal distance between the third fixed rod 641 and the center of the stage 61.

[0112] Here, the IPA nozzle 642 and the nitrogen nozzle 643 of the drying device 64 can rotate around the third fixed rod 641 and move to the top of the wafer, so as to spray isopropyl alcohol solution and / or nitrogen on the wafer to clean and dry the surface of the wafer. Among them, the IPA nozzle 642 and the nitrogen nozzle 643 can be arranged side by side and rotate synchronously. After the wafer is dried, the IPA nozzle 642 and the nitrogen nozzle 643 can be reset to avoid affecting the movement of the wafer.

[0113] In addition, during cleaning, the IPA nozzle 642 can be used to spray isopropyl alcohol solution to replace the solution on the wafer surface with the IPA solution, forming an IPA liquid film on the wafer surface. Then, the IPA solution is sprayed by the IPA nozzle 642 and the nitrogen nozzle 643 is used to spray nitrogen for drying, which can gradually dry the IPA liquid film, reduce residual water droplets, and improve the quality of the wafer surface.

[0114] In this embodiment, the two-fluid cleaning device 62, the deionized water cleaning device 63 and the drying device 64 can be respectively arranged at three corners of the cleaning chamber 61, so as to control the above three devices separately.

[0115] Optionally, the stage 65 includes a rotating platform 651 , a splash shield 652 and a plurality of claws 653 , and the single-wafer cleaning unit 6 also includes a waste discharge device 66 .

[0116] The rotating table 651 is used to place and rotate the wafer; a plurality of claws 653 are provided on the rotating table 651 to fix the wafer. When cleaning and drying the wafer, the claws 653 can be used to fix the wafer, and the rotating table 651 can be used to drive the wafer to rotate at a high speed, thereby improving the efficiency of cleaning and drying. In addition, the rotating table 651 can control the rotation speed of the wafer at different stages.

[0117] The splash shield 652 is disposed on the outside of the rotating machine 651. The splash shield 652 can block the cleaning solution, deionized water and isopropyl alcohol solution and collect them in the waste discharge system 66. Here, the splash shield can be retracted, and the splash shield 652 can be opened during the cleaning and drying process. After the drying is completed, the splash shield can be retracted and closed to facilitate the wafer removal.

[0118] The waste discharge device 66 is disposed at the bottom of the cleaning chamber 61 and is located between the rotating platform 651 and the splash shield 652 . The waste discharge system 66 can process the collected liquid and discharge it from the cleaning chamber 61 .

[0119] Optional, such as Figure 3 As shown, the single-wafer cleaning unit 6 also includes a fan filter device 67 ; the fan filter device 67 is disposed above the cleaning cavity 61 for filtering particles in the air and maintaining the pressure in the cleaning cavity 61 to maintain a high cleanliness of the cleaning cavity 61 .

[0120] The embodiment of the present application sets a surface modification unit in the cleaning module of the chemical polishing system, and can modify the surface of the cleaned wafer by plasma bombardment, generate hydrophilic functional groups on the wafer surface, modify the hydrophobic surface of the wafer to hydrophilic, enhance the wettability of the cleaning liquid, ensure that the cleaning liquid can evenly cover the surface of the wafer, and completely remove the residual pollutants and particulate matter; and, after the surface modification unit, a single-chip cleaning unit is set, and the modified wafer can be cleaned and dried by the single-chip cleaning unit. Since the surface of the wafer is changed to hydrophilic, the water droplets on the surface of the wafer can be reduced, the residual water droplets and the generation of surface defects can be reduced, and the yield of the wafer can be improved. Among them, the surface modification unit is added to the overall process of chemical mechanical polishing, and there is no need to perform it independently outside the production line, which can increase the integration of the system. In addition, the wafer can be moved between the flattening unit, the roller brush cleaning unit, the surface modification unit and the single-chip cleaning unit through the manipulator of the conveying module, and the first manipulator and the second manipulator do not contact the pollutants throughout the process, ensuring that the wafer is dry in and dry out.

[0121] The following is a method embodiment of the present application. For details not described in detail, please refer to the corresponding system embodiment described above.

[0122] Figure 4 The implementation flow chart of the chemical mechanical polishing method provided in the embodiment of the present application is applied to the chemical mechanical polishing system in the above-mentioned various embodiments of the present application. For the convenience of explanation, only the part related to the embodiment of the present application is shown. The method provided in the present application can be described in detail as follows:

[0123] Step 401 , sending a first wafer to be processed into a planarization unit 3 .

[0124] Here, the planarization module of the chemical mechanical polishing system can be provided with a plurality of planarization units 3, and the first wafer can be sent to the target planarization unit according to a preset rule to polish the wafer. The target planarization unit can be selected from the planarization units 3 in the planarization module according to a preset order.

[0125] For example, the planarization module includes two planarization units 3, namely A and B. A can be used as the target planarization unit to feed the first wafer into A, and then B can be used as the target planarization unit to feed the second wafer into B. After the first wafer is ground, A can be used as the target planarization unit again to feed the third wafer into A. By alternately using each planarization unit 3 as the target planarization unit, each planarization unit 3 can be used to grind the wafer at the same time, thereby improving the grinding efficiency.

[0126] In addition, the first robot 21 can be used to grab the first wafer to be processed from the loading and unloading port 1, and the first wafer can be transferred to the second robot 22, and then sent to the flattening unit 3 by the second robot 22.

[0127] Step 402 , controlling the planarization unit 3 to grind the first wafer to obtain a second wafer.

[0128] Step 403 , transferring the second wafer to the roller brush cleaning unit 4 .

[0129] Here, the third robot 23 can be used to grab the ground second wafer from the planarization unit 3 and send the second wafer to the roller brush cleaning unit 4 .

[0130] Step 404 , controlling the roller brush cleaning unit 4 to perform physical cleaning and chemical cleaning on the second wafer to obtain a third wafer.

[0131] The roller brush cleaning unit 4 is provided with a high-speed rotating brush, which can be used in combination with a cleaning liquid to clean the second wafer, thereby removing larger particles and impurities on the surface of the second wafer after grinding.

[0132] Step 405 , transferring the third wafer to the surface modification unit 5 .

[0133] In this embodiment, the fourth robot 24 can be used to grab the ground third wafer from the roller brush cleaning unit 4 and send the third wafer to the surface modification unit 5 .

[0134] A wafer carrying table 53 is provided in the surface modification unit 5 . Furthermore, the third wafer can be placed in the placement groove 531 of the wafer carrying table 53 by using the fourth robot 24 .

[0135] Step 406 , controlling the surface modification unit 5 to perform plasma bombardment on the third wafer to obtain a fourth wafer.

[0136] In this embodiment, the positioning member 533 at the bottom of the placement groove 531 can determine whether the third wafer is placed normally. In addition, the guide ring 534 can be used to limit the third wafer to ensure the stability of the third wafer placement and modification process. After the third wafer is placed correctly, the sealing gate 56 can be controlled to close, and the vacuum unit 52 can be used to evacuate the inside of the box 51 through the vacuum pipeline, and then plasma bombardment can be performed.

[0137] The plasma device 55 is controlled to start, and the plasma is bombarded onto the wafer surface through the plasma nozzle 58 to uniformly modify the wafer surface. At this time, the redundant matter and plasma will diffuse from the arranged through holes 532 and be absorbed by the suction device 54 located below to prevent the redundant matter from staying on the wafer surface. In addition, the suction device 54 can process the redundant matter and plasma, and then discharge and collect them through the exhaust pipe 57.

[0138] After the modification is completed, the atmospheric pressure in the box 51 is restored, the sealing gate 56 is opened, and the modified wafer can be taken out by the fifth robot 25 .

[0139] Step 407 , transferring the fourth wafer to the single wafer cleaning unit 6 .

[0140] The fifth robot 25 grabs the modified fourth wafer from the surface modification unit 5 and sends the fourth wafer to the single wafer cleaning unit 6 .

[0141] Here, a stage 65 for carrying wafers is provided in the single-wafer cleaning unit 6 , and the fifth robot 25 can place the fourth wafer on the stage 65 so as to clean and dry the fourth wafer.

[0142] Step 408 , controlling the single wafer cleaning unit 6 to clean and dry the fourth wafer to obtain a fifth wafer.

[0143] Optionally, the single-wafer cleaning unit 6 includes a cleaning chamber 61 , a two-fluid cleaning device 62 , a deionized water cleaning device 63 , a drying device 64 and a stage 65 .

[0144] In this embodiment, the single-wafer cleaning unit 6 is controlled to clean and dry the fourth wafer to obtain a fifth wafer, which can be:

[0145] Step 4081 , controlling the rotating platform 651 in the stage 65 to rotate, so as to rotate the fourth wafer on the rotating platform 651 .

[0146] In this embodiment, the fourth wafer may be placed on the rotating platform 651 of the stage 65 and fixed by a plurality of claws 653 to ensure stable rotation of the wafer.

[0147] Before cleaning the fourth wafer, the rotating platform 651 may be controlled to rotate, thereby driving the fourth wafer to rotate.

[0148] Optionally, the splash shield 652 in the stage 65 may be opened to collect the cleaning solution, deionized water and isopropyl alcohol solution.

[0149] Step 4082, controlling the two-fluid cleaning device 62 and the deionized water cleaning device 63 to clean the fourth wafer to form a deionized water film on the surface of the fourth wafer.

[0150] In this embodiment, the fourth wafer can be initially rinsed using a deionized water cleaning device 63, and then the fourth wafer can be cleaned using a cleaning fluid using a two-fluid cleaning device 62. After cleaning, the fourth wafer can be rinsed again using the deionized water cleaning device 63 to rinse off the cleaning fluid remaining on the surface of the wafer and form a deionized water film on the surface of the wafer.

[0151] The flow rate of SC1 solution in the cleaning solution may be in the range of 120 ml / min to 200 ml / min, the flow rate of nitrogen in the cleaning solution may be in the range of 20 L / min to 40 L / min, the flow rate of deionized water may be in the range of 1500 ml / min to 2000 ml / min, and the rotation speed of the wafer may be in the range of 500 rpm to 800 rpm.

[0152] Here, when the deionized water cleaning device 63 is used for rinsing, the second nozzle 632 of the deionized water cleaning device 63 can be rotated around the second fixing rod 631 to be directly above the center of the wafer to rinse the wafer surface. After the rinsing is completed, the second nozzle 632 is reset.

[0153] When using the two-fluid cleaning device 62 for cleaning, the first nozzle 622 of the two-fluid cleaning device 62 can also be rotated around the first fixed rod 621. When the first nozzle 622 cuts into the outer ring of the rotating wafer, it starts to spray the cleaning liquid. At this time, the first nozzle 622 still rotates around the first fixed rod 621 at a certain angular velocity. When the first nozzle 622 cuts out of the outer ring of the rotating wafer, it immediately stops spraying and starts to rotate and move in the opposite direction, returning to the point of entry with the wafer along the original path, forming a cycle. During the cleaning process, multiple cyclic sweeps can be performed to extensively clean the wafer surface. After cleaning is completed, the first nozzle 622 can be reset.

[0154] The sweep path of the first nozzle 622 is within the range of ±135 mm of the wafer radius.

[0155] Step 4083 , controlling the IPA nozzle 642 and the nitrogen nozzle 643 in the drying device 64 to rotate around the third fixed rod 641 , and rotating the IPA nozzle 642 to above the center of the rotating platform 651 .

[0156] In this embodiment, when drying the wafer surface, the IPA nozzle 642 and the nitrogen nozzle 643 of the drying device 64 are rotated around the third fixing rod 641 to the top of the wafer. Here, the IPA nozzle 642 can be located directly above the center of the wafer, and the nitrogen nozzle 643 can exceed the top by a certain distance.

[0157] In step 4084, the IPA nozzle 642 is controlled to spray the isopropyl alcohol solution on the center of the rotating table 651 to replace the deionized water film on the fourth wafer with the isopropyl alcohol liquid film.

[0158] In this embodiment, the IPA nozzle 642 is first controlled to spray the IPA solution, and the IPA solution diffuses outward at the center of the rotating wafer due to the centrifugal force. Through the Marangoni effect, the sprayed IPA solution can be used to replace the deionized water, and the water film can be gradually replaced by an isopropyl alcohol liquid film, so that the water can be evenly removed, thereby reducing residual water droplets and surface defects after drying.

[0159] Here, the flow rate of the IPA solution may range from 120 ml / min to 200 ml / min, and the rotation speed of the wafer may range from 100 rpm to 500 rpm, for example, 300 rpm.

[0160] Step 4085, reducing the flow rate of the isopropyl alcohol solution sprayed out by the IPA nozzle 642.

[0161] Step 4086, control the nitrogen nozzle 643 to spray nitrogen, and control the IPA nozzle 642 and the nitrogen nozzle 643 to rotate around the third fixed rod 641, so that the nitrogen nozzle 643 passes through the center of the rotating table 651 and rotates to the edge of the rotating table 651, drying the fourth wafer to obtain the fifth wafer.

[0162] Here, after the isopropyl alcohol liquid film is formed, the flow rate of the isopropyl alcohol solution can be reduced, and the wafer can be dried using nitrogen gas to achieve drying of the wafer.

[0163] The IPA nozzle 642 and the nitrogen nozzle 643 can move from just above the center of the wafer to the edge, with the IPA nozzle 642 in front and the nitrogen nozzle 643 in the back. The nitrogen sprayed by the nitrogen nozzle 643 can be used to gradually dry the IPA liquid film. When the nitrogen nozzle 643 passes the cut-out point of the outer circle of the wafer, the drying is completed.

[0164] During the drying process using nitrogen, the wafer rotation speed gradually decreases. For example, the wafer rotation speed gradually decreases to 430 rpm, wherein when the IPA nozzle is at the center, the wafer rotation speed may be 1100 rpm, and when the IPA nozzle is at the edge, the wafer rotation speed may be 430 rpm, and when the IPA nozzle 642 and the nitrogen nozzle 643 move toward the edge, the wafer rotation speed may decrease evenly.

[0165] In addition, after controlling the single-wafer cleaning unit 6 to clean and dry the fourth wafer to obtain the fifth wafer, the second robot 22 can also be used to take out the fifth wafer from the single-wafer cleaning unit 6 and pass it to the first robot 21, and the first robot 21 can send out the processed fifth wafer.

[0166] Optionally, after drying is completed, the splash shield may be retracted so that the fifth wafer can be subsequently taken out after drying.

[0167] In this embodiment, the hydrophobic surface of the wafer can be modified into a hydrophilic surface by plasma bombarding the wafer surface with a surface modification unit, thereby enhancing the wettability of the cleaning liquid and ensuring that the cleaning liquid can evenly cover the wafer surface to completely remove residual pollutants and particulate matter; the modified wafer is then cleaned and dried using a single-wafer cleaning unit, wherein a water film is first formed on the surface of the rotating wafer, and then the water film is replaced by an IPA solution, the water film on the wafer surface can be gradually replaced by an IPA liquid film, the moisture on the wafer surface is gradually discharged, and residual water droplets can be reduced, and then the rotating wafer is dried using an IPA solution and nitrogen, which can improve drying efficiency, reduce surface defects after drying, and ensure the quality of the wafer surface.

[0168] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0169] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0170] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0171] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A chemical mechanical polishing system, characterized in that: It includes a flattening module and a cleaning module; wherein the flattening module and the cleaning module are arranged in parallel; The planarization module includes at least one planarization unit, and the planarization unit is used to grind the wafer fed in; The cleaning module includes a roller brush cleaning unit, a surface modification unit and a single wafer cleaning unit arranged in sequence; the roller brush cleaning unit is used to physically and chemically clean the ground wafer; the surface modification unit is used to plasma bombard the surface of the cleaned wafer to generate hydrophilic functional groups on the wafer surface; the single wafer cleaning unit is used to clean and dry the modified wafer.

2. The chemical mechanical polishing system according to claim 1, characterized in that: The surface modification unit comprises a box, a vacuum device, a wafer carrier, a suction device and a plasma device; A sealing gate is provided on the side of the box; The vacuum device is arranged on the outer side of the box body and is connected with the interior of the box body through a vacuum pipe; The wafer carrying platform is fixed to the bottom of the box; a placement groove is provided on the wafer carrying platform, and a plurality of through holes arranged in a ring are provided at the bottom of the placement groove; wherein the placement groove is used to carry the wafer; The suction device is arranged below the wafer carrier and is connected to the placement groove through the plurality of through holes; the suction device is also connected to an exhaust gas pipeline running through the bottom of the box body, and is used to discharge redundant materials in the modification process through the exhaust gas pipeline; The plasma device is fixed on the top of the box body and communicated with the interior of the box body through a plasma nozzle; wherein the mouth of the plasma nozzle corresponds to the placement groove.

3. The chemical mechanical polishing system according to claim 2, characterized in that: A positioning piece is provided at the center of the bottom surface of the placement groove; A guide ring is also provided on the side of the placement groove, and the guide ring is used to limit the wafer.

4. The chemical mechanical polishing system according to claim 2, characterized in that: The single-wafer cleaning unit comprises a cleaning chamber, a two-fluid cleaning device, a deionized water cleaning device, a drying device and a stage; The stage is fixed to the bottom of the cleaning chamber and is used to carry the wafer; The two-fluid cleaning device comprises a first fixed rod and a first nozzle; the first fixed rod is fixed to the bottom of the cleaning chamber; the first nozzle is rotatably connected to the first fixed rod; wherein the rotation radius of the first nozzle is the horizontal distance between the first fixed rod and the center of the stage; The deionized water cleaning device comprises a second fixed rod and a second nozzle; the second fixed rod is fixed to the bottom of the cleaning chamber, and the second nozzle is rotatably connected to the second fixed rod; wherein the rotation radius of the second nozzle is the horizontal distance between the second fixed rod and the center of the stage; The drying device includes a third fixed rod, an IPA nozzle and a nitrogen nozzle; the third fixed rod is fixed to the bottom of the cleaning chamber, and the IPA nozzle and the nitrogen nozzle are both rotatably connected to the third fixed rod; wherein the rotation radius of the IPA nozzle and the nitrogen nozzle is the horizontal distance between the third fixed rod and the center of the stage.

5. The chemical mechanical polishing system according to claim 4, characterized in that: The stage includes a rotating platform, a splash shield and a plurality of claws, and the single-wafer cleaning unit also includes a waste discharge device; The rotating platform is used to place and rotate the wafer; The plurality of claws are arranged on the rotating platform and are used to fix the wafer; The splash shield is arranged on the outer side of the rotating platform; The waste discharge device is arranged at the bottom of the cleaning cavity and is located between the rotating machine table and the splash shield.

6. The chemical mechanical polishing system according to claim 4, characterized in that: The single-piece cleaning unit also includes a fan filter device; The fan filter device is arranged above the cleaning cavity and is used for filtering particles in the air and maintaining the pressure in the cleaning cavity.

7. The chemical mechanical polishing system according to any one of claims 1 to 6, characterized in that: The chemical mechanical polishing system further includes a wafer transfer module for moving the wafer between the planarization unit, the roller brush cleaning unit, the surface modification unit and the single wafer cleaning unit.

8. The chemical mechanical polishing system according to claim 7, characterized in that: The film transmission module includes a first manipulator, a second manipulator, a third manipulator, a fourth manipulator and a fifth manipulator; The first robot is used to obtain wafers to be processed and to deliver processed wafers; The second robot is arranged between the planarization module and the cleaning module, and is used to receive the wafer to be processed from the first robot and send it to the planarization unit, and to take out the processed wafer from the single-wafer cleaning unit and transfer it to the first robot; The third robot is arranged between the planarization module and the cleaning module, and is used to take out the wafer from the planarization unit and send it into the roller brush cleaning unit; The fourth robot is disposed between the roller brush cleaning unit and the surface modification unit, and is used to take out the wafer from the roller brush cleaning unit and send it into the surface modification unit; The fifth robot is arranged between the surface modification unit and the single-wafer cleaning unit, and is used for taking out the wafer from the surface modification unit and sending it into the single-wafer cleaning unit.

9. A chemical mechanical polishing method, characterized in that: Applicable to a chemical mechanical polishing system as described in any one of claims 1 to 8 above; the method comprises: Sending a first wafer to be processed into a planarization unit; Controlling the planarization unit to grind the first wafer to obtain a second wafer; transferring the second wafer to a roller brush cleaning unit; Controlling the roller brush cleaning unit to perform physical cleaning and chemical cleaning on the second wafer to obtain a third wafer; transferring the third wafer to a surface modification unit; controlling the surface modification unit to perform plasma bombardment on the third wafer to obtain a fourth wafer; Transferring the fourth wafer to a single wafer cleaning unit; The single wafer cleaning unit is controlled to clean and dry the fourth wafer to obtain a fifth wafer.

10. The chemical mechanical polishing method according to claim 9, characterized in that: The single-wafer cleaning unit comprises a cleaning chamber, a two-fluid cleaning device, a deionized water cleaning device, a drying device and a stage; The controlling the single-wafer cleaning unit to clean and dry the fourth wafer to obtain a fifth wafer comprises: Controlling the rotating table in the stage to rotate so as to rotate the fourth wafer on the rotating table; Controlling the two-fluid cleaning device and the deionized water cleaning device to clean the fourth wafer in sequence, so as to form a deionized water film on the surface of the fourth wafer; Controlling the IPA nozzle and the nitrogen nozzle in the drying device to rotate around the third fixed rod, and rotating the IPA nozzle to above the center of the rotating machine table; Controlling the IPA nozzle to spray the isopropyl alcohol solution onto the center of the rotating table to replace the deionized water film on the fourth wafer with the isopropyl alcohol liquid film; reducing the flow rate of the isopropyl alcohol solution sprayed from the IPA nozzle; The nitrogen nozzle is controlled to spray nitrogen, and the IPA nozzle and the nitrogen nozzle are controlled to rotate around the third fixed rod, so that the nitrogen nozzle passes through the center of the rotary table and rotates to the edge of the rotary table to dry the fourth wafer to obtain a fifth wafer.

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