Collision reflection type non-contact chemical mechanical polishing device

Abstract

The invention is suitable for the technical field of chemical mechanical polishing, and provides a collision reflection type non-contact chemical mechanical polishing device which comprises a polishing disc assembly and a cover plate assembly, the polishing disc assembly comprises a plurality of polishing discs, and the surface of each polishing disc is used for fixedly arranging a workpiece to be polished; the cover plate assembly is opposite to the surface of each polishing disk and is arranged at an interval to form a slit channel through which a polishing solution flows, and a plurality of reflecting surfaces for reflecting abrasive particles in the polishing solution are arranged on the surface, facing the polishing disk assembly, of the cover plate assembly; the reflected abrasive particles collide with the to-be-polished surface of the to-be-polished workpiece, redundant materials on the to-be-polished surface are removed, in the polishing process, the cover plate assembly does not make contact with the to-be-polished workpiece, mechanical scratches can be avoided, and more accurate and more uniform chemical mechanical polishing is achieved; in the polishing process, a polishing pad is not used, installation, finishing, adjustment and the like of the polishing pad are not needed, and the material cost and the use cost of the polishing pad can be saved.

Description

Technical Field

[0001] This application relates to the technical field of chemical mechanical polishing, and particularly to a collision reflection type non-contact chemical mechanical polishing device. Background Art

[0002] The full name of CMP (Chemical Mechanical Planarization / Polishing) is Chemical Mechanical Planarization / Chemical Mechanical Polishing. Its principle is to achieve the efficient removal of excess material on the surface of the workpiece to be polished, and even achieve global nanoscale planarization through the synergistic cooperation of chemical-mechanical dynamic coupling, chemical corrosion, and mechanical grinding. Among them, chemical corrosion refers to the chemical reaction between the polishing liquid and the surface of the workpiece to be polished, which reduces the hardness of the material on the surface of the workpiece to be polished, making it easier to remove; mechanical grinding refers to applying pressure to the polishing head, so that the workpiece to be polished on the polishing head and the polishing pad remove the material on the surface of the workpiece to be polished under the action of the frictional force generated during rotation.

[0003] Specifically, in the chemical mechanical polishing process, the workpiece to be polished is loaded on the polishing head, and the polishing pad is loaded on the polishing disk. When the polishing head and the polishing disk rotate, the polishing liquid will be brought under the workpiece to be polished. At this time, the components of the polishing liquid will react with the material on the surface of the workpiece to be polished, turning the material layer with high hardness into a material layer with low hardness. At the same time, the machine applies a certain pressure to the polishing head, causing mechanical friction between the workpiece to be polished and the polishing pad, thereby removing the material on the surface of the workpiece to be polished, and finally achieving global nanoscale planarization of the workpiece to be polished.

[0004] The problems existing in the existing chemical mechanical polishing devices and methods are that the workpiece to be polished is in direct contact with the polishing pad. Therefore, whether the polishing pad is installed flat and whether there are large particles on its surface, and whether the workpiece to be polished is installed flat and whether there are large particles on its surface will directly affect the surface polishing effect of the workpiece to be polished. That is, the polishing effect is directly determined by the surface contact situation between the polishing pad and the workpiece to be polished. This results in the polishing effect being greatly affected by the installation accuracy of the machine itself, the composition and performance of the polishing pad, and the operating habits of the operator, and often there are problems with poor polishing effects (such as scratches are likely to occur). Summary of the Invention

[0005] The purpose of the embodiments of this application is to provide a collision reflection type non-contact chemical mechanical polishing device, aiming to provide a solution that meets the global fine processing of the workpiece surface.

[0006] The embodiments of this application are implemented as follows. A chemical mechanical polishing device includes:

[0007] A polishing disk assembly, including a plurality of polishing disks, and the surface of each polishing disk is used for fixedly setting the workpiece to be polished; and

[0008] A cover plate assembly is arranged opposite to and spaced from the surface of each polishing disc, and a slit channel for the circulation of polishing liquid is formed between the cover plate assembly and the surface of the polishing disc assembly; wherein the surface of the cover plate assembly facing the polishing disc assembly is provided with a plurality of reflective surfaces for reflecting abrasive particles in the polishing liquid.

[0009] In one embodiment, the reflecting surface includes a smoothly transitioned arc surface and / or at least one plane, and the reflecting surface gradually tilts along the flow direction of the polishing liquid in a direction toward the polishing disk assembly.

[0010] In one embodiment, the cover plate assembly includes a cover plate body and a plurality of floating parts, wherein the slit channel is formed between the cover plate body and the surface of each polishing disk assembly; the floating parts are arranged on the cover plate body and can float toward and away from the polishing disk assembly; the reflecting surface includes the surface of one end of the floating parts facing the polishing disk assembly.

[0011] In one embodiment, the cover plate body is provided with a plurality of sliding holes from its surface facing the polishing disk assembly, the inner dimension of the sliding hole at one end facing the polishing disk assembly is smaller than the inner dimension of the sliding hole at one end away from the polishing disk assembly, and the outer dimension of the floating member gradually increases in a direction away from the polishing disk assembly so that a portion of the floating member can be exposed from the sliding hole toward the polishing disk assembly.

[0012] In one embodiment, the floating member is a sphere, and less than half of the sphere can be exposed from the sliding hole; or, the floating member includes a hemisphere close to the polishing disk assembly, and a column connected to the side of the hemisphere facing away from the polishing disk assembly, and a portion of the hemisphere can be exposed from the sliding hole.

[0013] In one embodiment, the chemical mechanical polishing device further comprises a retaining member, which is disposed on the cover plate body and is used to provide a retaining force to each of the floating members toward the polishing disk assembly.

[0014] In one embodiment, the retaining member includes a connecting tube and a retaining cavity, and the connecting tube is connected to the retaining cavity and each of the sliding holes, so that the sliding holes have the same fluid pressure as that in the retaining cavity.

[0015] In one embodiment, the chemical mechanical polishing device also includes a machine platform, and the polishing disc assembly is arranged on the machine platform; a liquid inlet chamber and a liquid outlet chamber are provided on the machine platform, which are respectively located on both sides of the slit channel and connected to the slit channel, and the cross-sectional area of ​​the liquid inlet chamber is larger than the cross-sectional area of ​​the slit channel; at least a portion of the liquid inlet chamber serves as the retaining chamber.

[0016] In one embodiment, a groove is provided on a side of the cover plate body facing away from the polishing disc assembly, and one end of each sliding hole facing away from the polishing disc assembly communicates with the groove respectively; the cover plate assembly further includes a closing plate, the closing plate is provided on a side of the cover plate assembly facing away from the polishing disc assembly and is hermetically connected to the cover plate assembly around the groove; a communication hole is provided on the closing plate, and the communication pipe communicates with the groove through the communication hole.

[0017] In one embodiment, the chemical mechanical polishing device further includes a first driving assembly, and the first driving assembly is used to drive each polishing disc to rotate.

[0018] In one embodiment, the polishing disc assembly further includes a plurality of carrier discs, a plurality of second accommodation grooves are provided on the carrier discs, and each polishing disc is respectively arranged in the second accommodation groove; the first driving assembly is used to drive the carrier disc to rotate around its own central axis, and drive each polishing disc to revolve around the central axis of the carrier disc and rotate around its own central axis.

[0019] The beneficial effects of the chemical mechanical polishing device provided by the embodiments of the present application are as follows:

[0020] The chemical mechanical polishing device provided by the embodiments of the present application uses a plurality of reflecting surfaces on the cover plate assembly to reflect abrasive grains, so that the reflected abrasive grains collide with the surface to be polished of the workpiece to be polished, removing the excess material on the surface to be polished. During the polishing process, the cover plate assembly does not contact the workpiece to be polished, which can avoid mechanical scratches and achieve more precise and uniform chemical mechanical polishing; no polishing pad is used during the polishing process, and there is no need to install, trim, adjust, etc. the polishing pad, which can save the material cost and use cost of the polishing pad.

[0021] In addition, in the chemical mechanical polishing device provided by the embodiments of the present application, when the surface to be polished is close to the reflecting surface to a certain extent, the floating member and its reflecting surface will automatically float in a direction away from the polishing disc assembly. Therefore, even if there is a large abnormal axial jump of the polishing disc, it will avoid the direct contact between the surface to be polished of the workpiece to be polished and the reflecting surface, and avoid the resulting mechanical scratches.

[0022] The chemical mechanical polishing device provided by the embodiments of the present application can conveniently adjust the polishing removal rate of the surface to be polished and the surface roughness obtained after polishing by controlling the flow rate of the polishing liquid, and can simultaneously achieve a high polishing removal rate and a small roughness of the polished surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 is the front view of the chemical mechanical polishing device provided by the embodiment of the present application;

[0025] Figure 2 is the sectional view of the chemical mechanical polishing device provided by the embodiment of the present application;

[0026] Figure 3 is the schematic principle diagram of the chemical mechanical polishing device provided by the embodiment of the present application;

[0027] Figure 4 is the sectional structure schematic diagram of the cover plate assembly in the chemical mechanical polishing device provided by the embodiment of the present application;

[0028] Figure 5 is Figure 4 the enlarged view of part A in;

[0029] Figure 6 is the partial enlarged view of another structure of the cover plate assembly in the chemical mechanical polishing device provided by the embodiment of the present application, corresponding to Figure 4 part A in;

[0030] Figure 7 is the three-dimensional structure schematic diagram of the cover plate body in the chemical mechanical polishing device provided by the embodiment of the present application;

[0031] Figure 8 is the partial structure schematic diagram of the machine table in the chemical mechanical polishing device provided by the embodiment of the present application;

[0032] Figure 9 is the partial structure schematic diagram of the first driving assembly in the chemical mechanical polishing device provided by the embodiment of the present application;

[0033] Figure 10 is the schematic diagram of the floating principle of the floating part in the chemical mechanical polishing device provided by the embodiment of the present application.

[0034] The meanings of the marks in the figure are:

[0035] 100 - chemical mechanical polishing device;

[0036] 1 - machine table, 10 - first accommodation groove, 15 - slit channel, 16 - liquid inlet cavity, 17 - liquid outlet cavity;

[0037] 2 - polishing disc assembly, 21 - carrier plate, 210 - second receiving groove, 22 - polishing disc;

[0038] 3 - cover plate assembly, 31 - cover plate body, 310 - sliding hole, 311 - groove;

[0039] 32 - floating member, 320 - reflecting surface, 321 - hemispherical body, 322 - cylinder;

[0040] 33 - closing plate, 330 - communication hole;

[0041] 4 - holding member, 41 - communication pipe, 42 - holding cavity;

[0042] 5 - first driving assembly, 51 - power member, 52 - synchronization structure, 53 - rotating shaft, 54 - sun gear, 56 - planetary gear;

[0043] 6 - second driving assembly;

[0044] 71 - pump body, 72 - filtering assembly, 73 - liquid storage part;

[0045] 8 - workpiece to be polished;

[0046] X - first axis, Y - second axis. Detailed implementation manners

[0047] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] It should be noted that when a component is referred to as "fixed to" or "disposed on" another component, it can be directly or indirectly fixed or disposed on the other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to the other component. The orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of this patent. Terms "first" and "second" are only used for the purpose of convenient description, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of technical features. The meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0049] In order to illustrate the technical solutions described in the present application, the following will be described in detail with reference to specific accompanying drawings and embodiments.

[0050] The CMP equipment mainly consists of three major structural units: a transfer unit, a polishing unit, and a cleaning unit. The transfer unit mainly consists of components such as a front-end module and a workpiece transfer robot. Among them, the front-end module is responsible for docking with the workpiece handling system in the factory and transporting the workpiece into the machine for processing. The workpiece transfer robot is responsible for transferring the workpiece inside the polishing unit and the cleaning unit and between different processing stations.

[0051] The polishing unit mainly includes a polishing platen, polishing heads, a polishing liquid supply system, and a polishing endpoint detection system. By using the synergistic cooperation of chemical corrosion and mechanical grinding, the surface planarization of the workpiece is achieved through the relative movement between the grinding head holding the workpiece and the polishing pad. A certain flow rate of polishing liquid is dripped between the polishing pad and the workpiece. The corrosion effect generated by the chemical components in the polishing liquid and the mechanical friction force generated by the solid particles in the polishing liquid are used to remove the excess material on the surface of the workpiece, achieving global planarization of the workpiece. Endpoint detection technology is used to continuously detect the material thickness on the surface of the workpiece and stop polishing after reaching the predetermined thickness. After chemical mechanical polishing is completed, the cleaning unit effectively removes the particulate contaminants on the surface of the workpiece and dries the workpiece.

[0052] Workpiece loading during polishing: During polishing, the workpiece adheres to or is adsorbed under the polishing head. The polishing head rotates in the same direction as the polishing pad under the actuation of, for example, pneumatic components above and applies a downward load to the workpiece to enable the workpiece to undergo the CMP process. As the size of the workpiece being processed increases, in order to adapt to workpieces of different sizes and shapes, the polishing head is required to have an adaptive loading technology, that is, the polishing head should be as compatible as possible with materials of different sizes and shapes to reduce the cost input of the polishing equipment.

[0053] Loading of the polishing pad and polishing liquid during polishing: During polishing, the polishing pad is actuated by a driving device under the machine table to drive the polishing pad to rotate, enabling the polishing pad to undergo the CMP process with the workpiece under the action of the polishing liquid. Since the global flatness requirement for the workpiece surface during polishing reaches nanometer-level accuracy, the flatness of the polishing platen itself should be very high, the elastic modulus should be very large, and the expansion coefficient should be very small. As the size of the workpiece being processed increases, the size of the polishing platen also needs to increase. In order to achieve a high-quality polishing effect, the design, manufacturing, and assembly processes of the polishing platen must all reach very high precision.

[0054] Dressing: The polishing pad itself will gradually become smooth during the polishing process due to surface wear and compression. The surface of the polishing pad is used to transport the polishing liquid and drain the polishing waste liquid. The grooves on the surface of the polishing pad will also be filled with abrasive grains and polishing residues, etc., resulting in a decrease in the polishing ability of the polishing pad. In order to obtain the desired polishing effect, the surface of the polishing pad must be dressed regularly to remove the by-products accumulated on the polishing pad and restore the polishing effect of the polishing pad. The dressing rings used for dressing are mostly composed of a metal matrix + diamond abrasive grains. Among them, the size and morphology of the diamond abrasive grains have a greater impact on the dressing speed and dressing effect.

[0055] Pressure control: The main pressure control methods adopted in the CMP process are mainly three types: counterweight pressurization method, cylinder pressurization method, and airbag structure pressurization method. (1) The counterweight pressurization method is to place counterweight blocks on the back of the disk that bonds the workpiece, and rely on the weight of the counterweight blocks themselves to provide the pressure required during the polishing process. The main feature is that the pressure value remains constant throughout the polishing process, with little fluctuation, and it is impossible to dynamically adjust the pressure according to the process requirements. It is difficult to optimize the polishing process plan, and the polishing efficiency is low. (2) The cylinder pressurization method is to use the output force of the cylinder to provide the pressure required during the polishing process. The main feature is that the polishing pressure is changed by adjusting the air pressure. Due to the poor pressure stability of the air pressure system, the polishing pressure fluctuates greatly, and there will be an impact phenomenon during pressure loading. In terms of structural design, a double-cylinder combination method is often adopted to separate the lifting mechanism and the pressure loading mechanism of the polishing head to improve the accuracy and sensitivity of pressure control. (3) The airbag structure pressurization method is to use an airbag to transfer the polishing pressure during the pressure loading process. Its greatest advantage is that it can achieve flexible pressure transfer, which is conducive to uniform pressure distribution. At the same time, the good buffering performance of the airbag structure can reduce the fluctuation during the polishing process.

[0056] The cleaning unit generally includes a megasonic cleaning module, a brushing module, and a drying module, etc. The megasonic cleaning module uses the energy of megasonic waves and the corrosive effect of chemical liquids to achieve the removal of large particles. The brushing module uses the dual effects of the corrosion of chemicals and mechanical brushing to remove the strongly adhering particles on the surface of the workpiece, and rinses the residues with ultrapure water. The drying module removes the water stains on the surface of the workpiece through the centrifugal force generated by high-speed rotation to achieve the drying of the workpiece.

[0057] Disk surface temperature control: During the CMP process, the polishing head and the polishing disk are rotating at a certain speed. The workpiece contacts the polishing pad under the load of the polishing head and moves relative to it. Because a lot of heat is generated by mechanical friction, the temperature of the polishing disk surface will continue to rise as the heat accumulates during the polishing process. And obviously, under the same conditions, as the size of the workpiece increases, the heat generation will also increase. The influence of temperature on the polishing effect is multifaceted. First, it causes the polishing pad to be locally deformed by heat, changing its elasticity and global flatness, thereby changing the uniformity of the pressure distribution on the wafer surface, making the consistency of the material removal rate worse during the polishing process, and ultimately resulting in a decrease in the warpage and curvature of the workpiece after polishing, affecting the polishing effect; second, it affects the chemical reaction rate between the polishing liquid and the wafer, destroying the consistency of different batches of products in mass production. Therefore, in order to obtain the ideal polishing rate and polishing effect, it is necessary to take control measures on the disk surface temperature. The main way is to control the disk surface temperature through the polishing disk circulating water cooling system. The temperature control principle is that when the temperature sensor above the polishing disc detects that the disc temperature has reached the set value, the water pump is started to circulate the water, and the circulating water removes the excess heat from the disc, so that the temperature falls back to the set range. The cooling effect is related to the circulating water path under the polishing disc. A more reasonable path design can enhance the cooling effect of the circulating water and achieve a more precise and rapid temperature control effect.

[0058] With the growth of workpiece size and the continuous advancement of process technology nodes, CMP equipment is also constantly upgrading. For example, the pressure control system adopts more advanced zone pressure control technology for mainstream large-size workpiece production lines. In the processing of large-size workpieces, the linear speed of different areas varies greatly due to the large diameter of the workpiece. Only by accurately adjusting the pressure distribution in different areas can the uniformity of polishing force and the consistency of polishing quality be guaranteed.

[0059] In the semiconductor industry chain, wafer processing is a high-value, high-precision, and high-tech manufacturing process, and is the most important link in the semiconductor chip industry. The wafer processing and manufacturing process can be divided into three major modules: wafer substrate manufacturing, front-end processing, and back-end processing. In the wafer substrate manufacturing, the wafer rod slices need to be CMP processed after grinding. In the front-end processing, the diffusion-deposition-photolithography-etching-ion implantation-CMP process needs to be repeated several times. Therefore, the CMP process is an important process throughout the entire wafer processing. Especially as the chip process becomes smaller and smaller and the internal structure becomes more and more complex, the CMP process has become more and more important. When the chip process comes below 7 nanometers, the CMP process has reached 30 or even more. CMP equipment is the processing platform required to complete the CMP process.

[0060] If global nanoscale planarization of the wafer surface cannot be achieved during the wafer processing, key processes such as lithography, etching, thin film, and doping cannot be repeated, and the process nodes cannot be reduced to the advanced nanoscale field. Therefore, as the line width of very large scale integrated circuit manufacturing continues to shrink, the CMP process plays an irreplaceable and increasingly important role in advanced process manufacturing.

[0061] The upgrade of the chip manufacturing process has put forward higher requirements for polishing uniformity. The control requirement for global uniformity has been increased from dozens of nanometers to a few nanometers. To meet the requirements of polishing uniformity, future pressure control needs to set more reasonable and fine partitions for the polishing head and cooperate with intelligent algorithms to solve the problem of mutual coupling of multiple partitions.

[0062] The third-generation semiconductor materials represented by silicon carbide (SiC) have excellent bandgap width and chemical stability. While opening up a new world for material selection in the integrated circuit industry, they also bring many challenges to the CMP process. Due to its high hardness and high chemical inertness, the traditional CMP process has gradually reached a bottleneck in removal efficiency. To effectively improve the processing efficiency of silicon carbide, many research teams have developed various different composite CMP process technologies based on the CMP process, including electrochemical mechanical polishing (ECMP), ultrasonic-assisted chemical mechanical polishing (UCMP), chemical magnetorheological composite polishing (CMRF), photocatalytic-assisted chemical mechanical polishing (PCMP), atmospheric pressure plasma-assisted abrasive polishing (PAP), etc. However, processes such as CMRF, PCMP, and PAP have problems such as low removal rate and very high processing cost, and are temporarily limited to the laboratory research stage. Here, the electrochemical mechanical polishing (ECMP) process is mainly introduced.

[0063] The principle of electrochemical polishing is to use silicon carbide as the anode and a Pt (platinum) rod as the cathode. Under the action of a DC power supply, anodic oxidation occurs on the surface of silicon carbide, turning it into a silica layer with lower hardness, and then using a softer abrasive to grind and remove it, ultimately achieving surface planarization of the silicon carbide workpiece.

[0064] The CMP and ECMP processes can balance the relationship between roughness and removal rate and meet the processing requirements of silicon carbide materials. Among them, the MRR removal rate of the ECMP process is the highest, which can reach 2 - 3 times that of the traditional CMP process, and the roughness can also be maintained at a relatively good level.

[0065] This application is committed to providing another chemical mechanical polishing method, hoping to eliminate the use of the polishing pad and the friction polishing of the workpiece 8 to be polished, so as to meet the global fine processing of the surface of the workpiece 8 to be polished.

[0066] Next, please refer to Figures 1 to 3As shown, an embodiment of the present application provides a chemical mechanical polishing device 100, which is specifically a collision reflection type non-contact chemical mechanical polishing device.

[0067] See also Figure 3 As shown, the chemical mechanical polishing device 100 provided in the embodiment of the present application includes a polishing disc assembly 2 and a cover plate assembly 3. The polishing disc assembly 2 includes a plurality of polishing discs 22, and the surface of each polishing disc 22 is used to fix a workpiece 8 to be polished. The cover plate assembly 3 is opposite to the surface of each polishing disc 22 and is arranged at intervals. A slit channel 15 for the circulation of polishing liquid is formed between the cover plate assembly 3 and the surface of each polishing disc 22. Please refer to Figure 5 and Figure 6 As shown, the surface of the cover plate assembly 3 facing each polishing disc 22 is provided with a plurality of reflective surfaces 320 for reflecting abrasive particles in the polishing liquid.

[0068] In the chemical mechanical polishing device 100, the polishing liquid flows through the slit channel 15, that is, the polishing liquid flows through the surface of each workpiece 8 to be polished that is away from the polishing plate 22 (the surface to be polished of the workpiece 8 to be polished). The polishing liquid includes chemical substances and abrasive particles. Since the surface of the cover plate assembly 3 facing each polishing plate 22 is provided with a plurality of reflecting surfaces 320, when the abrasive particles flow in the slit channel 15 as a whole, they will be reflected by the reflecting surfaces 320 and change the direction of movement. The reflected abrasive particles move toward each polishing plate 22 ( Figure 3 The small straight arrow in the figure indicates the movement direction of the abrasive particles, and the large straight arrow indicates the flow direction of the polishing liquid). As a result, the abrasive particles can collide with the polishing surface of the workpiece 8 to be polished, remove the excess material on the polishing surface that has been softened (due to the weakened bonding force caused by the reaction with the chemical substances in the polishing liquid), and complete the chemical mechanical polishing of the polishing surface.

[0069] Some of the removed material is mixed in the polishing fluid and carried away.

[0070] The chemical mechanical polishing device 100 provided in the embodiment of the present application utilizes multiple reflective surfaces 320 on the cover plate assembly 3 to reflect abrasive particles, so that the reflected abrasive particles collide with the polishing surface of the workpiece 8 to be polished, thereby removing excess material on the surface to be polished. During the polishing process, there is no contact between the cover plate assembly 3 and the workpiece to be polished, thereby avoiding mechanical scratches and achieving more precise and uniform chemical mechanical polishing. During the polishing process, no polishing pad is used, and there is no need to install, trim, or adjust the polishing pad, thereby saving the material cost and usage cost of the polishing pad.

[0071] The chemical mechanical polishing device 100 provided in the embodiment of the present application can be used for any type of workpiece 8 to be polished, and can be any workpiece that needs to be polished. For example, the workpiece 8 to be polished can be a metal workpiece, a ceramic workpiece, a glass workpiece, or a plastic workpiece. Specifically, the workpiece 8 to be polished includes but is not limited to a wafer.

[0072] The workpiece 8 to be polished can be directly fixed on the polishing disc 22, or it can be fixed on the polishing disc 22 by other mounting plates (not shown). For example, the mounting plate is detachably fixed on the polishing disc 22 by gluing, vacuum adsorption or mechanical fixing, and the workpiece 8 to be polished is detachably fixed on the mounting plate. More specifically, the workpiece 8 to be polished is attached to the mounting plate by thermal adhesive. After polishing, the mounting plate and the workpiece 8 to be polished are removed from the polishing disc 22 as a whole, and then the thermally sensitive denaturation characteristics of the thermal adhesive are used to separate the mounting plate from the polished workpiece. In more optional embodiments, the workpiece 8 to be polished can be fixed by other means, and the polished workpiece can be removed by other means, and examples are not given one by one.

[0073] See also Figures 1 to 3 As shown, the chemical mechanical polishing device 100 may further include a machine table 1, which is used for fixed installation, for example, it can be fixedly installed on the ground or a platform surface. The polishing disc assembly 2 and the cover plate assembly 3 are both arranged on the machine table 1. The machine table 1 is used to carry the polishing disc assembly 2 and the cover plate assembly 3 at a suitable position, for example, at a suitable height.

[0074] See also Figure 1 As shown, in one embodiment, the chemical mechanical polishing device 100 further includes a first driving assembly 5 , which is disposed on the machine platform 1 , connected to the polishing disc assembly 2 , and used to drive each polishing disc 22 to rotate.

[0075] The purpose of this arrangement is that when the polishing liquid flows through the slit channel 15, each polishing disc 22 drives the workpiece 8 to be polished to rotate, so that each part of the surface to be polished can collide with the abrasive particles evenly, and the position and movement trajectory of the abrasive particles relative to the workpiece 8 to be polished are further disordered and random, thereby avoiding the generation of polishing unevenness on the polishing surface corresponding to the reflection surface 320 and the liquid flow direction.

[0076] In one embodiment, the first drive assembly 5 is configured to drive each polishing disc 22 to revolve (rotate together around the first axis X, see Figure 9 As shown) and self-rotation (rotation around its own central axis, the central axis of each polishing disc 22 itself is shown in Figure 9 Please refer to Figure 3 and Figure 9As shown, the first driving assembly 5 includes a power member 51, a sun gear 54, and a plurality of planetary gears 56. Among them, the power member 51 is used to drive the sun gear 54 to rotate, and the planetary gears 56 are evenly distributed and meshed with the sun gear 54. As Figure 3 shown, the polishing disc assembly 2 may further include a carrier plate 21. The carrier plate 21 is fixedly and coaxially connected to the sun gear 54. Each polishing disc 22 is rotatably arranged on the carrier plate 21 and is fixedly and coaxially connected to the planetary gear 56 respectively.

[0077] Among them, in another embodiment, the first driving assembly 5 can drive each polishing disc 22 to rotate around its respective central axis. The form of the first driving assembly 5 is not limited. For example, the first driving assembly 5 can be a plurality of power members 51, which are respectively connected to a polishing disc 22 to drive a polishing disc 22 to rotate; or, the first driving assembly 5 can include a power member 51 and a transmission member (not shown), and a power member 51 drives a plurality of polishing discs 22 to rotate simultaneously through the transmission member.

[0078] Among them, in yet another embodiment, the first driving assembly 5 can drive each polishing disc 22 to rotate around a common axis. For example, each polishing disc 22 is fixedly arranged on the carrier plate 21, and the power member 51 drives the carrier plate 21 to rotate around its central axis, so that each polishing disc 22 rotates together, or each polishing disc 22 is fixedly connected together as a whole, and the power member 51 drives each polishing disc 22 to rotate simultaneously.

[0079] In other embodiments, the first driving assembly 5 can have other structural ways to drive the polishing disc 22 to revolve and / or rotate. Here is only an example and is not particularly limited.

[0080] As Figure 2 and Figure 3 shown, in one embodiment, the drive shaft of the power member 51 and the rotating shaft 53 are parallel and spaced apart, and are connected by a synchronization structure 52 such as a synchronous belt or a meshing gear, so that the power member 51 can drive the rotating shaft 53 to rotate. The purpose of such a setting is to facilitate the layout of the position of the power member 51 and can reduce the overall height of the chemical mechanical polishing device 100.

[0081] Please refer to Figures 1 to 3 shown, a plurality of first accommodation grooves 10 are provided on the carrier plate 21, and each polishing disc 22 is placed in the first accommodation groove 10. Please refer to Figure 3 shown, a second accommodation groove 210 is provided on the surface of the machine table 1, and the carrier plate 21 is arranged in the second accommodation groove 210.

[0082] The first receiving groove 10 and the second receiving groove 210 are provided to ensure that the surface to be polished, the surface of the carrier plate 21, and the surface of the machine 1 are substantially flush or even flush, so that the height difference of the slit channel 15 at various locations is not too large or even no height difference. The height of the slit channel 15 at various locations is close to or even the same, which is conducive to ensuring that the flow rate of the polishing liquid at various locations in the slit channel 15 is close to or even the same.

[0083] It should be noted that, for the solution in which the polishing disc 22 rotates relative to the carrier disc 21, the outer dimensions of the polishing disc 22 are designed to be smaller than the inner dimensions of the first receiving groove 10. In order to prevent the polishing liquid from leaking from the outer edge of the polishing disc 22 and the inner circumferential wall of the first receiving groove 10, a seal (not shown) is provided between the outer edge of the polishing disc 22 and the inner circumferential wall of the first receiving groove 10. Similarly, when the carrier disc 21 needs to rotate relative to the machine 1, a seal is provided between the outer edge of the carrier disc 21 and the inner circumferential wall of the second receiving groove 210. The form and material of the seal are not limited, and it can be one or more sealing rings.

[0084] like Figure 8 As shown, the second accommodating groove 210 can be a double-step groove, the inner dimensions of which are larger at the side facing the cover plate assembly 3 and the side facing away from the cover plate assembly 3 than at the middle part, and the rotating shaft 53 is connected to the carrying plate 21 by passing through the step groove from the bottom of the carrying plate 21. The double-step groove can limit the jumping of the carrying plate 21 in the upward direction and the downward direction, ensure the stability of the vertical position of each polishing plate 22 and the workpiece 8 to be polished, and further ensure the uniformity of the polishing surface.

[0085] In addition, bearings can be provided between the carrier plate 21 and the machine table 1, and between the polishing plate 22 and the carrier plate 21, so as to further limit and reduce the axial runout of the carrier plate 21 and the polishing plate 22. In specific applications, through the cooperation of the first drive assembly 5 and the bearings, the axial runout of the carrier plate 21 and the polishing plate 22 can be limited to an accuracy of 0.05 mm. On this basis, the smaller the axial runout of the carrier plate 21 and the polishing plate 22, the better.

[0086] In other embodiments, the axial runout of the carrier plate 21 and the polishing plate 22 can be limited as much as possible by other means.

[0087] The chemical mechanical polishing device 100 provided in the embodiment of the present application has no special requirements on the rotation speed of the carrier plate 21 and the polishing plate 22. For example, it can generally be controlled below 100 rpm. Of course, this is only an example. According to the size of the polishing plate 22 and the position distribution on the carrier plate 21, the rotation speed of the carrier plate 21 and the polishing plate 22 can have other numerical ranges respectively. A lower rotation speed can more easily ensure low axial runout of the carrier plate 21 and the polishing plate 22.

[0088] See alsoFigure 1 and Figure 2 As shown in Figure 2 , the chemical mechanical polishing apparatus 100 further includes a second driving assembly 6. The second driving assembly 6 is connected to the cover plate assembly 3 and is configured to drive the cover plate assembly 3 to move toward and away from the polishing platen assembly 2. When the cover plate assembly 3 approaches the polishing platen assembly 2, a slit channel 15 as described above is formed between the cover plate assembly 3 and the polishing platen assembly 2 to perform a polishing process; when the cover plate assembly 3 moves away from the polishing platen assembly 2, operations such as loading a workpiece 8 to be polished, removing a polished workpiece, or other inspections and repairs can be performed.

[0089] The form of the second driving assembly 6 is not limited. For example, the second driving assembly 6 can be a hydraulic component, a pneumatic component, an electric component, or a magnetic control component. In practical applications, the second driving assembly 6 can lift and lower the cover plate assembly 3 along the vertical direction or a direction close to the vertical direction, or can also drive the cover plate assembly 3 to move away from or close to the machine table 1 in a flipping manner.

[0090] In practical applications, in order to enable the abrasive grains in the polishing liquid to collide with the surface to be polished after being reflected by the reflecting surface 320, the polishing platen assembly 2 is located below the cover plate assembly 3, as Figures 1 to 3 shown. That is, the polishing liquid flows through the upper surfaces of the respective polishing platens 22, and the upper surface of the workpiece 8 to be polished serves as the surface to be polished.

[0091] In some embodiments, the second driving assembly 6 is further configured to be able to adjust the height of the cover plate assembly 3 to adjust the clearance height between the cover plate assembly 3 and the machine table 1, and further adjust the height between the cover plate assembly 3 and the upper surface of the workpiece 8 to be polished. That is, the height of the slit channel 15 can be adjusted within a certain range. Different heights of the slit channel 15 determine different flow rates of the polishing liquid in the slit channel 15.

[0092] Regarding the shape of the reflecting surface 320, please refer to Figure 5 and Figure 6 shown. In the direction toward the polishing platen assembly 2, the reflecting surface 320 gradually inclines along the flow direction of the polishing liquid. Such a reflecting surface 320 can reflect the abrasive grains flowing with the polishing liquid to the side of the polishing platen 22.

[0093] Please refer to Figure 5 and Figure 6 shown. The reflecting surface 320 is a smoothly transitioning arc surface. The purpose of such a setting is to be able to reflect the abrasive grains in more directions, making the movement paths of the abrasive grains more random and disordered to ensure the uniformity of the collision between the abrasive grains and the surface to be polished.

[0094] The specific surface type of the so-called smoothly transitioning arc surface is not limited. For example, it can be a spherical surface, an ellipsoidal surface, a non-spherical surface, or a free surface, etc.

[0095] In one embodiment, the reflecting surface 320 may further include one or more planes.

[0096] In one embodiment, the reflecting surface 320 may also be a combination of at least one plane and a smoothly transitioning arcuate surface.

[0097] In one embodiment, the so-called reflecting surface 320 is the fixed surface of the cover plate assembly 3 facing the polishing platen assembly 2. For example, it may be a convex arc surface, a wedge surface, a conical surface, etc. integrally formed on the cover plate assembly 3.

[0098] Please refer to Figure 3 、 Figure 4 and Figure 5 As shown, in one embodiment, the cover plate assembly 3 includes a cover plate body 31 and a plurality of floating members 32. A slit channel 15 as described above is formed between the cover plate body 31 and the surface of the machine table 1. The floating members 32 are provided on the cover plate body 31 and can move towards and away from the polishing platen assembly 2.

[0099] Among them, the surface of one end of the floating member 32 facing the polishing platen assembly 2 serves as the reflecting surface 320. Please refer to Figure 5 and Figure 6 As shown. The floating members 32 are provided on one side of the cover plate body 31 facing the polishing platen assembly 2. A part of the floating members 32 can be located within the slit channel 15.

[0100] Please refer to Figure 10 As shown, when the polishing liquid flows in the slit channel 15, the polishing liquid (fluid) will exert a pressure on the floating member 32 in a direction away from the polishing platen 22. This pressure comes from the static pressure of the fluid in the slit channel 15. In the embodiment of the present application, calculated per unit area, the magnitude (value) of this pressure is equal to the static pressure P of the fluid in the slit channel 15 狭缝 . Please refer to Figure 3 As shown, the chemical mechanical polishing apparatus 100 further includes a holding member 4. The holding member 4 is connected to each floating member 32 and is used to provide a pressure to each floating member 32 in the direction towards the polishing platen 22. Similarly calculated per unit area, define the pressure in the direction towards the polishing platen 22 as P 保持 .

[0101] During normal polishing, P 狭缝 < P 保持 , which enables the floating member 32 to be maintained at the lowest position within the floating range of the floating member 32 at the limit position close to the polishing platen 22, as shown in Figure 10 (b) in

[0102] According to the Bernoulli principle, the total pressure of the fluid M = static pressure P + dynamic pressure Q (Note: the premise is that the fluid is a non-compressible liquid and flows on the same horizontal line. The fluid in this embodiment meets this premise). The total pressure remains constant along the streamline, that is, the static pressure and dynamic pressure of the fluid maintain a dynamic balance. Therefore, the total pressure of the fluid in the slit channel 15 is M 狭缝 =P 狭缝 +Q 狭缝 Among them, the calculation formula of dynamic pressure Q is: Q = ρv 2 / 2 (ρ is the density of the fluid, v is the velocity of the fluid).

[0103] In the slit channel 15, at the moment when the gap between the surface to be polished and the floating member 32 is infinitely close to 0, the flow of the fluid is blocked, and the dynamic pressure Q of the fluid in the slit channel 15 is 狭缝 The hydrostatic pressure P acting on the floating member 32 decreases. 狭缝 Increase. When P 狭缝 >P 保持 When the floating member 32 moves away from the polishing plate assembly 2, refer to Figure 10 As shown in (a).

[0104] The purpose of such arrangement is that, in the process of driving the polishing discs 22 to rotate, the first driving assembly 5 may generate axial runout due to accidental reasons, especially upward axial runout, causing the polishing disc 22 and the workpiece 8 to be polished to run toward the direction close to the cover plate assembly 2. When the upward axial runout occurs, at the moment when a certain local position of the surface to be polished is extremely close to the reflection surface 320, the flow of the fluid at this position in the slit channel 15 is blocked, and the dynamic pressure is converted into static pressure, causing the static pressure P at this position in the slit channel 15 to be 狭缝 Rapidly increase. 狭缝 >P 保持 , the fluid pushes the floating member 32 at this position to move away from the surface to be polished, thereby preventing the reflective surface 320 from contacting the surface to be polished. That is, even if the polishing disc 22 and the workpiece 8 to be polished axially approach and jump a certain distance, the surface to be polished will not be mechanically scratched by the reflective surface 320.

[0105] Based on the above, whether the floating member 32 moves away from the polishing plate assembly 2 or remains close to the polishing plate 22 depends on the hydrostatic pressure P generated by the polishing liquid in the slit channel 15. 狭缝 and the holding force P provided by the holding member 4 保持 The difference in size (see Figure 10 When P 狭缝 >P 保持 When P 狭缝 <P 保持When in this state, the floating member 32 is held at the limit position close to the polishing disc 22.

[0106] Therefore, through the floating setting of the floating member 32 and the cooperation of the holding member 4, it is achieved that even if the polishing disc 22 accidentally has an abnormal upward jump, the workpiece 8 to be polished will not be mechanically scratched.

[0107] The gap between the reflecting surface 320 of the floating member 32 and the surface of the polishing disc 22 can be set according to actual needs, so that when the workpiece 8 to be polished is fixed on the polishing disc 22, there is an appropriate gap between the reflecting surface 320 of the floating member 32 and the surface to be polished. For example, in some embodiments, the adjustment range of the gap between the reflecting surface 320 of the floating member 32 and the surface to be polished is greater than 0 and less than or equal to 5 millimeters. This is only an example. Depending on the type of the workpiece 8 to be polished, the gap between the reflecting surface 320 of the floating member 32 and the surface to be polished can be adjusted to other values, and no further examples will be given one by one.

[0108] There are various ways to implement the holding member 4.

[0109] For example, in one embodiment, the holding member 4 includes an elastic member (not shown), specifically such as a spring, an elastic material column structure, an elastic layer, etc. The elastic member is provided on the cover body 31, and the floating member 32 is provided on the elastic member. The elastic member, by its own elastic deformation, is used to provide a holding force F towards the polishing disc assembly 2 to the floating member 32. In this embodiment, the holding force F may not be a constant force, because for the elastic member, the holding force F is related to its own elastic deformation amount.

[0110] Please refer to Figure 3 、 Figure 4 and Figure 5 As shown in the figures, in one embodiment, the cover body 31 is provided with a plurality of sliding holes 310 from its surface facing the polishing disc assembly 2. The inner dimension D1 of one end of the sliding hole 310 facing the polishing disc assembly 2 is smaller than the inner dimension D2 of its end far from the polishing disc assembly 2. The outer dimension of the floating member 32 gradually decreases in the direction close to the polishing disc assembly 2 (the outer dimension of the floating member 32 gradually decreases starting from D3, and D1 < D3 < D2), so that a part of the floating member 32 can be exposed from the sliding hole 310 towards the polishing disc assembly 2. And in the direction towards the polishing disc assembly 2, the floating member 32 is restricted and cannot completely escape from the sliding hole 310.

[0111] In this embodiment, please refer to Figure 3As shown, the holding member 4 includes a communicating pipe 41 and a holding cavity 42. The communicating pipe 41 communicates with the holding cavity 42 and each sliding hole 310, specifically, the end of each sliding hole 310 facing away from the polishing disc assembly 2. There is liquid flow in the holding cavity 42, and this fluid also generates static pressure. Due to the arrangement of the communicating pipe 41, this static pressure acts on the floating member 32 as the holding force P of the floating member 32. 保持 .

[0112] Further optionally, please refer to Figure 3 and Figure 8 As shown, on the machine table 1, there are a liquid inlet cavity 16 and a liquid outlet cavity 17 which are respectively located on both sides of the slit channel 15 and communicate with the slit channel 15. Among them, the cross-sectional area of the liquid inlet cavity 16 is larger than that of the slit channel 15. The machine table 1 can be a frame bearing structure with a certain height. Figure 8 In , only a part of the machine table 1 is shown, such as the part for setting the polishing disc assembly 2.

[0113] Since the cross-sectional area of the liquid inlet cavity 16 is larger than that of the slit channel 15, when the polishing liquid enters the slit channel 15 from the liquid inlet cavity 16, the polishing liquid is accelerated to a higher flow rate, generating an appropriate polishing removal rate.

[0114] Further optionally, please refer to Figure 3 and Figure 8 As shown, one end of the communicating pipe 41 communicates with the liquid inlet cavity 16, and the other end of the communicating pipe 41 communicates with the end of each sliding hole 310 facing away from the polishing disc assembly 2. That is to say, at least a part of the liquid inlet cavity 16 can serve as the holding cavity 42. The purpose of such an arrangement is to omit the additional setting of a holding cavity 42 and simplify the structure of the chemical mechanical polishing device 100.

[0115] Since each sliding hole 310 communicates with the liquid inlet cavity 16 and the liquid inlet cavity 16 communicates with the slit channel 15, therefore, the total fluid pressure in the liquid inlet cavity 16 is the same as the total fluid pressure in the slit channel 15. The total fluid pressure M = M 狭缝 = P 狭缝 + Q 狭缝 , the total fluid pressure M = M 保持 = P 保持 + Q 保持 , where P 保持 is the static pressure of the fluid in the liquid inlet cavity 16, that is, the static pressure acting on the floating member 32, and Q 保持 is the dynamic pressure of the fluid in the liquid inlet cavity 16.

[0116] During normal polishing, since the cross-sectional area of the slit channel 15 is smaller than that of the holding cavity 42, therefore, the fluid velocity v 狭缝 in the slit channel 15 is greater than the fluid velocity v 保持 in the holding cavity 42, that is, Q狭缝 >Q 保持 , correspondingly, P 狭缝 <P 保持 , which enables the floating member 32 to be maintained at the lowest position within the floating range of the floating member 32 near the polishing disc 22 at the limit position, as shown in Figure 10 (b) therein.

[0117] When the upward axial runout of the optical disc 22 occurs, at the moment when a certain local position of the surface to be polished is extremely close to the reflecting surface 320, the fluid flow at this position in the slit channel 15 is blocked, and the dynamic pressure is converted into static pressure, resulting in a rapid increase in the static pressure P at this position within the slit channel 15. Due to the inertia of fluid flow and the lag of pressure transmission, the fluid velocity and pressure within the liquid inlet chamber 16 still remain at the values before the axial runout occurs at this moment. Therefore, the static pressure P provided by the liquid inlet chamber 16 acting on the floating member 32 at this position also still maintains the value before the axial runout occurs. As a result, at this moment, P 狭缝 >P 保持 in the slit channel 15, and the fluid in the slit channel 15 pushes the floating member 32 at this position in a direction away from the surface to be polished, thereby preventing the reflecting surface 320 from contacting the surface to be polished. 狭缝 >P 保持 The floating principle of the floating member 32 is specifically introduced as follows:

[0118] On the one hand, the polishing liquid in the liquid inlet chamber 16 exerts a pressure on the floating member 32 through the connecting pipe 41 in the direction towards the polishing disc 22, and its magnitude is equal to the fluid static pressure P in the liquid inlet chamber 16.

[0119] On the other hand, the polishing liquid in the slit channel 15 exerts a pressure on the floating member 32 in the direction away from the polishing disc 22, and its magnitude is equal to the fluid static pressure P in the slit channel 15. 保持 According to Bernoulli's principle, the total pressure M of the fluid = static pressure P + dynamic pressure Q. Therefore, M = P 狭缝 + Q 保持 = P 保持 + Q 狭缝 = P 狭缝 + Q 保持 , where Q

[0120] is the dynamic pressure of the polishing liquid in the liquid inlet chamber 16. 2 / 2, the fluid velocity in the slit channel 15 is greater than the fluid velocity in the liquid inlet chamber 16. Therefore, Q 保持 < Q 狭缝 , P 保持 > P 狭缝 . As a result, the floating member 32 is maintained at the lowest position near the polishing disc assembly 2, as shown in Figure 10 (b) therein.

[0121] When the polishing disc 22 accidentally has abnormal axial runout, the surface to be polished will approach or even reach the lowest position of the floating member 32. If the floating member 32 and its reflecting surface 320 cannot move away from the polishing disc 22, the surface to be polished will come into contact with the reflecting surface 320, resulting in mechanical scratches on the surface to be polished.

[0122] Therefore, in the embodiment of the present application, through the connection of the above-mentioned liquid inlet cavity 16 and each sliding hole 310 through the connecting pipe 41, when the above-mentioned abnormal axial runout occurs and the surface to be polished approaches the lowermost end of the floating member 32 infinitely, the flow of the polishing liquid in the slit channel 15 is blocked, and part of the dynamic pressure of the fluid in the slit channel 15 is converted into static pressure, so that P 狭缝 >P 保持 , this pressure difference pushes the floating member 32 and its reflecting surface 320 to move away from the polishing disc 22, as shown in (a) of Figure 10 , avoiding the contact between the surface to be polished and the reflecting surface 320 and the resulting mechanical scratches on the surface to be polished.

[0123] Conversely, when the upward axial runout disappears, the polishing disc 22 and the workpiece 8 to be polished fall downward, the gap between the surface to be polished and the reflecting surface 320 increases, the fluid in the slit channel 15 resumes flowing, and has a part of Q 狭缝 , the static pressure P of the fluid in the slit channel 15 狭缝 decreases until P 狭缝 <P 保持 , and the floating member 32 can move downward again and remain at the lowest position.

[0124] The pressure generated by the self-weight of the floating member 32 is in the same direction as P 保持 , and they can be superimposed on each other. Usually, the pressure generated by the self-weight of the floating member 32 is negligible compared to P 保持 .

[0125] For example, taking the steel floating member 32 as an example, for a solid sphere with a diameter of 1 cm as the floating member, its self-weight is equivalent to providing a pressure of about 5 g / cm² to 15 g / cm² (the specific value depends on the diameter of the contact position between the floating member and the sliding hole near the polishing disc 22). In practical applications, the hydrostatic pressure provided by the polishing liquid in the liquid inlet cavity 16 can reach 1 kg / cm² to 3 kg / cm². Therefore, the gravity of the floating member 32 can be ignored.

[0126] Please refer to Figure 3 , Figure 4 and Figure 7 shown. In one embodiment, a groove 311 is provided on the side of the cover plate body 31 facing away from the polishing disc assembly 2, and one end of each sliding hole 310 facing away from the polishing disc assembly 2 is respectively communicated with the groove 311. AsFigure 3 As shown, the chemical mechanical polishing device 100 further includes a closing plate 33. The closing plate 33 is disposed on a side of the cover plate body 31 facing away from the polishing disc assembly 2 and is sealingly connected to the cover plate body 31 around the groove 311. A communication hole 330 is provided on the closing plate 33, and the communication hole 330 is respectively communicated with the other end of the communication pipe 41 and the groove 311.

[0127] By providing the closing plate 33 and its communication hole 330, simultaneous communication between the cavity 42 and the plurality of sliding holes 310 is achieved. In practical applications, the closing plate 33 and the surface of the cover plate body 31 on the side facing away from the polishing disc assembly 2 are detachably connected, so as to facilitate the assembly of the floating member 32 and the replacement of the floating member 32 after the floating member 32 is worn. Here, the way of detachable connection is not limited.

[0128] Optionally, as Figure 3 and Figure 8 shown, the cross-sectional area of the liquid outlet cavity 17 is also larger than the cross-sectional area of the slit channel 15. For example, the cross-sectional area of the liquid outlet cavity 17 can be close to or equal to the cross-sectional area of the liquid inlet cavity 16. Specifically, the shape of the liquid outlet cavity 17 can be set to be generally mirror-symmetrical with the shape of the liquid inlet cavity 16.

[0129] The specific form of the floating member 32 is not limited, as long as it can partially protrude from the sliding hole 310 and enter the slit channel 15.

[0130] Please refer to Figure 5 shown. In one embodiment, the floating member 32 is a sphere, and less than one-half of the sphere can be exposed from the sliding hole 310. The "sphere" here does not refer to a structure with a completely precise spherical surface, but refers to a structure in which the dimensions of the floating member 32 in three-dimensional directions are not very different. In addition to being able to float in the direction towards and away from the polishing disc assembly 2, the floating member 32 of this spherical structure can also rotate in at least two directions. Thus, the abrasion of the floating member 32 by the abrasive grains in the polishing liquid can be reduced.

[0131] Or, as Figure 6 shown, the floating member 32 includes a hemispherical body 321 close to the polishing disc assembly 2 and a column body 322 connected to the side of the hemispherical body 321 facing away from the polishing disc assembly 2. A part of the hemispherical body 321 can be exposed from the sliding hole 310. It should also be noted that the "hemispherical body 321" here does not refer to exactly half of a structure with a completely precise spherical surface, and the column body 322 is not limited to a cylindrical body, a prismatic body or other forms of column bodies, but refers to a structure with relatively obvious dimensions in the floating direction of the floating member 32. In addition to being able to float in the direction towards and away from the polishing disc assembly 2, the floating member 32 of this structure can also rotate in one direction, and can also reduce the abrasion of the floating member 32 by the abrasive grains in the polishing liquid.

[0132] The material of the floating member 32 is not limited, and a material with relatively high hardness can be selected. For example, the material of the floating member 32 may include metals, ceramics, etc.

[0133] In some cases, the floating member 32 may have a relatively small size relative to the cover plate body 31. For example, please refer to Figure 7 As shown, dozens, hundreds or even thousands of sliding holes 310 and their corresponding floating members 32 can be provided on the cover plate body 31. Of course, according to the application scenario of the chemical mechanical polishing device 100, the number and size of the floating members 32 can also have other values. Here, only examples are given and no specific limitations are made. Among them, the smaller the size of the floating member 32, the more uniform and random the reflection effect on the abrasive grains. Therefore, in practical applications, the size and number of the floating members 32 should be comprehensively considered in terms of facilitating processing, assembly and combining with the polishing effect.

[0134] Please continue to refer to Figure 3 As shown, along the flow direction of the polishing liquid, the downstream of the liquid outlet cavity 17 can be sequentially connected to the liquid storage part 73 and the pump body 71, and the pump body 71 drives the polishing liquid to circulate between the liquid inlet cavity 16, the slit channel 15, the liquid outlet cavity 17 and the liquid storage part 73. The liquid storage part 73 can be the internal cavity of a liquid storage container (not shown). Optionally, in Figure 3 the chemical mechanical polishing device 100 may further include a filtering component 72. The filtering component 72 is arranged between the pump body 71 and the liquid inlet cavity 16, and is used to filter out large particle foreign matters in the polishing liquid before it enters the liquid inlet cavity 16, so as to avoid mechanical hard scratches on the workpiece 8 to be polished caused by large particle foreign matters.

[0135] In other alternative embodiments, the polishing liquid may have a one-way flow path from the liquid inlet cavity 16, the slit channel 15 to the liquid outlet cavity 17. The upstream of the liquid inlet cavity 16 is connected to a liquid supply container (not shown), and the downstream of the liquid outlet cavity 17 is connected to a liquid collection container (not shown), which will not be elaborated here.

[0136] The chemical mechanical polishing device 100 provided by the embodiments of the present application can flexibly adjust the polishing removal rate of the surface to be polished and the roughness of the obtained polished surface by controlling the flow rate of the polishing liquid. Specifically, the faster the flow rate of the polishing liquid, the higher the polishing removal rate, and the greater the roughness of the obtained polished surface. On the contrary, the slower the flow rate of the polishing liquid, the lower the polishing removal rate, and the smaller the roughness of the obtained polished surface. In practical applications, different flow rate control strategies can be adopted at different stages of polishing. For example, first use a large liquid flow rate for chemical mechanical polishing to achieve a higher polishing removal rate, and then reduce the liquid flow rate to perform chemical mechanical polishing at a smaller liquid flow rate, which can achieve a smaller roughness of the polished surface. Specifically, the flow rate of the polishing liquid can be adjusted by setting a flow rate regulating valve (not shown) on the flow path of the polishing liquid or directly adjusting the flow rate of the pump.

[0137] The specific materials of the chemical substances and abrasive grains in the polishing liquid are not limited. For example, in one embodiment, the abrasive grains are alpha-aluminum trioxide particles with a particle size of 100 nanometers to 300 nanometers, which are mixed in a potassium permanganate solution with a concentration of 4% to 5%.

[0138] By selecting appropriate processes and appropriate polishing liquids, high polishing accuracy and polishing rate can be achieved. In a specific embodiment, the polishing liquid made of the above materials is used to polish a 6-inch silicon carbide substrate for 2 hours, and the surface roughness of the obtained substrate is less than 0.1 nanometer, and the polishing removal rate reaches 2.6 micrometers per hour.

[0139] In addition, for the chemical mechanical polishing device 100 provided in the embodiments of the present application, since non-contact polishing is achieved, the requirements for the hardness, strength, and shape of the abrasive grains in the polishing liquid are lower. For example, the hardness of the abrasive grains does not need to be very high, the shape of the abrasive grains does not need to be too demanding, and the requirement for the particle size uniformity of the abrasive grains is also lower, etc., so that the cost of the polishing liquid can be significantly reduced.

[0140] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A chemical mechanical polishing device, characterized in that: include: A polishing disc assembly, comprising a plurality of polishing discs, wherein the surface of each polishing disc is used to fix a workpiece to be polished; as well as A cover plate assembly is arranged opposite to and spaced from the surface of each polishing disc, and a slit channel for the circulation of polishing liquid is formed between the cover plate assembly and the surface of the polishing disc assembly; wherein the surface of the cover plate assembly facing the polishing disc assembly is provided with a plurality of reflective surfaces for reflecting abrasive particles in the polishing liquid.

2. The chemical mechanical polishing device according to claim 1, characterized in that: The reflecting surface includes a smoothly transitioned arc surface and / or at least one plane, and the reflecting surface gradually inclines along the flow direction of the polishing liquid in the direction toward the polishing disc assembly.

3. The chemical mechanical polishing device according to claim 1, characterized in that: The cover plate assembly includes a cover plate body and a plurality of floating parts, wherein the slit channel is formed between the cover plate body and the surface of each polishing disk assembly; the floating parts are arranged on the cover plate body and can float toward and away from the polishing disk assembly; the reflecting surface includes the surface of one end of the floating parts facing the polishing disk assembly.

4. The chemical mechanical polishing device according to claim 3, characterized in that: The cover body is provided with a plurality of sliding holes from its surface facing the polishing disk assembly, the inner dimension of the sliding hole at one end facing the polishing disk assembly is smaller than the inner dimension of the sliding hole at one end away from the polishing disk assembly, and the outer dimension of the floating member gradually increases in the direction away from the polishing disk assembly so that a portion of the floating member can be exposed from the sliding hole toward the polishing disk assembly.

5. The chemical mechanical polishing device according to claim 4, characterized in that: The floating member is a sphere, and less than half of the sphere can be exposed from the sliding hole; or, the floating member includes a hemisphere close to the polishing disk assembly, and a column connected to the side of the hemisphere facing away from the polishing disk assembly, and a part of the hemisphere can be exposed from the sliding hole.

6. The chemical mechanical polishing device according to claim 4, characterized in that: The chemical mechanical polishing device further comprises a retaining member, which is arranged on the cover plate body and is used to provide a retaining force to each of the floating members toward the polishing disc assembly.

7. The chemical mechanical polishing device according to claim 6, characterized in that: The retaining member includes a connecting pipe and a retaining cavity, wherein the connecting pipe is connected to the retaining cavity and each of the sliding holes so that the sliding holes have the same fluid pressure as that in the retaining cavity.

8. The chemical mechanical polishing device according to claim 7, characterized in that: The chemical mechanical polishing device also includes a machine platform, and the polishing disc assembly is arranged on the machine platform; a liquid inlet cavity and a liquid outlet cavity are respectively located on both sides of the slit channel and connected to the slit channel, and the cross-sectional area of ​​the liquid inlet cavity is larger than the cross-sectional area of ​​the slit channel; at least a part of the liquid inlet cavity serves as the retaining cavity.

9. The chemical mechanical polishing device according to claim 7, characterized in that: A groove is provided on the side of the cover plate body facing away from the polishing disk assembly, and one end of each sliding hole facing away from the polishing disk assembly is respectively connected to the groove; the cover plate assembly also includes a closing plate, which is provided on the side of the cover plate assembly facing away from the polishing disk assembly and is sealed and connected to the cover plate assembly around the groove; a connecting hole is provided on the closing plate, and the connecting pipe is connected to the groove via the connecting hole.

10. The chemical mechanical polishing device according to any one of claims 1 to 9, characterized in that: The chemical mechanical polishing device further comprises a first driving assembly, and the first driving assembly is used for driving each of the polishing discs to rotate.

11. The chemical mechanical polishing device according to claim 10, characterized in that: The polishing disc assembly also includes a plurality of carrier discs, each of which is provided with a plurality of second accommodating grooves, and each of the polishing discs is respectively arranged in the second accommodating groove; the first driving assembly is used to drive the carrier discs to rotate around their own central axes, and to drive each of the polishing discs to revolve around the central axis of the carrier disc and to rotate around its own central axis.

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