System for chemical mechanical polishing and planarization

Abstract

Disclosed is a system for chemical mechanical polishing and planarization, said system at least comprising a polishing head. The polishing head comprises: a polishing head body; a rigid disc, on a lower surface of which a plurality of air holes are formed and inside of which a third air cavity in communication with the air holes is formed; an elastic unit, which is at least partially of an annular structure, the elastic unit being separately connected to the polishing head body and the rigid disc, and the polishing head body, the elastic unit, and the rigid disc forming a second air cavity; and a retaining ring, which is located below the polishing head body. When the third air cavity is in a negative pressure state, the lower surface of the rigid disc can make contact with and suction onto a wafer substrate, the pressure in the second air cavity can be controlled so as to drive the elastic unit to flexibly move, so as to assist the rigid disc and the wafer substrate to float, achieving chemical mechanical polishing of the wafer substrate. According to the present invention, rigid driving in the rigid disc solves the problem of breakage or changes in elastic modulus due to a flexible film being dragged under severe polishing conditions when the flexible film drives the wafer substrate to be polished, thus prolonging the service life of flexible parts.

Description

A chemical mechanical polishing and planarization system Technical Field

[0001] The present invention belongs to the technical field of semiconductor integrated circuit chip manufacturing, and in particular relates to a chemical mechanical polishing and planarization system. Background Art

[0002] The wafer substrate and semiconductor device manufacturing process includes processes such as polishing and surface planarization. Mechanical polishing, chemical mechanical polishing, or planarization techniques are typically used. A wafer carrier (polishing head) applies pressure to the wafer backside, controlling parameters such as pressure, polishing head speed, polishing disk speed, and polishing fluid flow rate. The front surface or thin film surface of the wafer substrate is polished or planarized on a polishing pad. Compared to mechanical polishing, chemical mechanical polishing and planarization achieve higher polishing or planarization efficiency by adjusting the polishing fluid formula to produce a chemical reaction on the wafer surface. This results in better polishing or planarization results, including higher flatness and lower defectivity. There are two main ways in which the polishing head applies pressure to the wafer substrate. One is flexible membrane air cavity pressurization. In short, the flexible membrane in direct contact with the wafer substrate can be single-cavity or multi-cavity. By controlling the pressure in the flexible membrane cavity, the pressure distribution on the wafer substrate is adjusted, thereby achieving regional thickness control of the wafer substrate. The other is hard disk pressurization. The hard disk is in direct contact with the wafer substrate. The hard disk is driven by a hard guide rod. The hard guide rod directly applies vertical downward pressure to the hard disk, which acts relatively evenly on the wafer substrate. Compared with the above two methods, the advantage of the flexible air cavity pressurization method is that the pressure of the wafer substrate area can be adjusted and the local area can be modified, but it has little effect on the overall thickness change of the wafer substrate. The hard disk solution can optimize the overall thickness change of the wafer substrate to a certain extent, but it has no local area modification capability.

[0003] On the basis of the chemical mechanical polishing and planarization described above, for conductive substrates or film conductive materials, the conductive properties of the wafer substrate or the thin film on the wafer surface can be further utilized, and an electrochemical reaction can be carried out on the surface of the wafer substrate or the thin film through an electrochemical mechanical polishing and planarization system. Through the precise control of the circuit system, the surface chemical reaction rate is increased, thereby improving the efficiency of mechanical polishing and planarization. The polishing head in the commonly used embodiment is mainly of the insulating type. This insulating polishing head does not participate in the circuit architecture. In some embodiments, a hard-contact vacuum conductive suction cup head is used. The circuit architecture of the current electrochemical mechanical polishing and planarization equipment is very complex. In addition, electrode wear and hard contact will also increase the risk of metal contamination and wafer substrate scratches during the process. In addition, one of the current paths in the current electrochemical mechanical planarization equipment is that the electrode is realized through the edge position of the polishing platform. Therefore, there is uneven current size and distribution from the center to the edge on the polishing platform. Two of these methods use a vacuum conductive chuck head to hold the wafer in place. The movement of the mobile polishing platform results in a small relative travel between the wafer and the polishing plate, which can lead to uneven electrochemical reactions on the wafer. Furthermore, this type of conductive chuck head is often a hard plate loaded by a spindle. Rigid conductive plates lack in-plane pressure regulation and therefore cannot act on the wafer surface for in-plane uniformity control. Furthermore, there is an electropolishing head that loads electrodes around the outer circumference of the wafer, creating planar conduction on the polished surface of the wafer through multi-point contact. However, this electrode design is complex and wears out from contact with the outer circumference of the wafer. The two conventional chemical mechanical polishing and planarization methods mentioned above include flexible chamber pressurized polishing heads and hard plate polishing heads (where the wafer substrate is attached to the lower surface of the hard plate via wax / film sealing). Both the flexible rubber airbag and the hard plate wax / film sealing methods described above are electrically insulating or weakly conductive, and cannot achieve the goal of conducting ampere-level currents from the wafer through the polishing head. Therefore, the main difficulty limiting the application of conductive polishing heads is, on the one hand, the need to realize multiple tasks such as wafer substrate loading, unloading, and pressurization, and on the other hand, the need to meet the requirements of high conductivity.

[0004] Based on the aforementioned background technology, conventional chemical mechanical polishing and planarization heads cannot achieve both optimized overall thickness variation and locally modifiable functionality. Therefore, the technical approaches of these two polishing heads can be combined to develop a new polishing head that, while utilizing a rigid disk for overall thickness adjustment, also incorporates flexible cavity control for localized thickness adjustment. Furthermore, for electrochemical polishing and planarization, the rigid disk of these polishing heads can be treated with a conductive material, enabling the application of these new polishing heads in electrochemical polishing and planarization technologies.

[0005] Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the present invention provides a chemical mechanical polishing and planarization system. The hard disk can realize the loading and unloading of wafer substrates through pressure control of the third cavity, and can also adsorb or not adsorb the wafer substrate. The elastic unit and the second air cavity are used to cooperate to control the hard disk to move with the wafer substrate, thereby ensuring effective chemical mechanical polishing and planarization of the wafer substrate while extending the service life of the polishing head.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a chemical mechanical polishing and planarization system, comprising at least a polishing head, the polishing head comprising:

[0008] Polishing head body;

[0009] A hard disk, wherein at least a portion of its lower surface is located in the same plane, and a plurality of air holes are formed in the portion of the lower surface located in the same plane, and a third air cavity is formed inside the hard disk and is connected to the air holes;

[0010] The elastic unit is at least partially annular and is connected to the polishing head body and the hard disk, and the polishing head body, the elastic unit and the hard disk are surrounded to form a second air cavity;

[0011] A retaining ring is an annular component located below the polishing head body and capable of contacting the polishing pad. The hard disk moves within the area defined by the retaining ring.

[0012] When the third air cavity is in a negative pressure state, the lower surface of the hard disk can contact and adsorb the wafer substrate, and the pressure in the second air cavity is controllable to drive the elastic unit to move flexibly, assisting the hard disk and wafer substrate to float, thereby realizing chemical mechanical polishing of the wafer substrate.

[0013] Furthermore, the hard disk is made of a conductive material or has a conductive surface treatment to achieve electrochemical mechanical polishing and planarization of the wafer substrate.

[0014] Furthermore, in electrochemical mechanical polishing and planarization of the wafer substrate, the circuit is connected from the elastic unit to the hard disk, or the circuit is directly connected to the hard disk from the electrode, or the circuit is connected to the hard disk from the polishing head body.

[0015] Furthermore, the horizontal portion of the lower surface of the hard disk; or the horizontal portion of the lower surface of the hard disk forms a thickened area or a thinned area to form a height difference from nanometer level to micrometer level.

[0016] Furthermore, the elastic unit is made of elastic material, one side of its annular structure is connected to the outer ring of the hard disk, and the other side is fixedly connected between the polishing head body and the retaining ring.

[0017] Furthermore, the central axis of the polishing head body extends toward the direction of the hard disk to form a guide cylinder, and the side of the hard disk facing away from the wafer substrate forms a guide sleeve, which is concentric and coaxial with the hard disk. The guide cylinder extends into the guide sleeve, or the guide sleeve extends into the guide cylinder, and there is a radial movable gap between the two.

[0018] Furthermore, one of the guide cylinder and the guide sleeve is provided with at least one driving pin, and the other is provided with a driving groove, the driving pin extends into the driving groove, and there is a circumferential movable gap between the two.

[0019] Furthermore, the number of the driving pins and the number of the driving slots are equal.

[0020] Furthermore, the hard disk is provided with a guide rod, and the guide rod extends vertically upward from the center of the polishing head body.

[0021] Furthermore, a conduit is provided inside the guide rod, and the conduit is communicated with the third air cavity.

[0022] Furthermore, the central axis of the polishing head body extends toward the hard disk to form a guide cylinder, one of the guide cylinder and the guide rod is provided with at least one driving pin, and the other is provided with a driving groove, the driving pin extends into the driving groove, and there is a circumferential movable gap between the two.

[0023] Furthermore, a flexible cloth is attached to the lower surface of the hard disk, and the flexible cloth includes air holes, and the air holes match the positions of at least some of the air holes of the hard disk.

[0024] Furthermore, the flexible cloth is a conductive flexible cloth.

[0025] Furthermore, the flexible cloth is made of non-conductive material, and the pores of the flexible cloth are filled with electrolyte, so that the wafer substrate and the polishing head body are electrically connected.

[0026] Furthermore, the flexible cloth is a sponge structure, or the flexible cloth is a foamed polymer.

[0027] Furthermore, the polishing head body includes at least one fourth air cavity located above the hard disk. The air pressure in the fourth air cavity is variable so as to pressurize or depressurize a specific area of ​​the hard disk.

[0028] Furthermore, the fourth air cavity is located above the central area of ​​the hard disk, or the fourth air cavity is an annular or disc-shaped air cavity located above and concentric with the hard disk.

[0029] Furthermore, the polishing head body is formed with a first air cavity, which is used to control the up and down stroke of the polishing head body.

[0030] Furthermore, the diameter of the pores is 0.1-3 mm, and the total area of ​​the pores accounts for 0.1-5% of the lower surface area of ​​the hard disk.

[0031] Furthermore, a waterproof and breathable layer is provided on the lower surface of the hard disk.

[0032] Furthermore, the hard disk is provided with an edge limiter, which can respectively abut against the cut edge of the wafer substrate and the inner wall of the retaining ring, or it can abut against the cut edge of the wafer substrate.

[0033] Furthermore, the retaining ring has a groove for the polishing liquid to enter and exit, and the edge limiting member is provided with a guide groove that can be connected to the groove; the edge limiting member is made of insulating material.

[0034] The beneficial effects of the present invention are: 1) the use of a hard disk can achieve relatively uniform overall downward pressure, which helps to improve the overall thickness variation; 2) the use of an elastic unit for local pressure application can help to modify the local area of ​​the hard disk; 3) when the flexible membrane is used as a driving component to drive the wafer substrate to polish, when encountering areas such as grooves on the polishing pad, its force balance state will fluctuate, which will affect the polishing speed and the polishing efficiency. The hard drive in the hard disk has higher stability, which can effectively avoid the above problems and has better process stability; 4) the hard drive in the hard disk solves the problem that when the flexible membrane drives the wafer substrate to polish under harsh polishing conditions, the flexible membrane is pulled and causes cracks or changes in elastic modulus, thereby extending the service life of the flexible parts in the polishing head; 5) the negative pressure of the hard disk is used to adsorb the wafer substrate, and when the polishing head leaves the polishing pad, the wafer substrate will not be caused by the return of the flexible membrane. The scraping between the wafer substrate and the polishing pad ensures that the wafer substrate is quickly and effectively separated from the polishing pad, ensuring the orderly progress of the polishing process; 6) It can be applied to ordinary chemical mechanical polishing. By conducting conductive treatment on the hard disk, the application of electrochemical polishing and planarization processes can be realized, and it has high adaptability; 7) Using a conductive hard disk, the circuit between the polishing head and the wafer substrate is connected for electrochemical mechanical polishing and planarization, which can ensure the long-term stability of the electrochemical reaction and the process stability of electrochemical mechanical polishing and planarization is higher; 8) The edge limit configured for wafer substrates of specific shapes can effectively prevent the edge oxidation of the hard disk or the conductive flexible film thereon, thereby increasing the service life of the above components; 9) Using a hard disk in conjunction with a flexible cavity to perform overall and local pressurization on the wafer substrate, it is possible to optimize the total thickness change of the wafer substrate while modifying the local area. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a front view of a first embodiment of the present invention.

[0036] FIG2 is a first schematic diagram of the three-dimensional structure of the first embodiment of the present invention.

[0037] FIG3 is a second schematic diagram of the three-dimensional structure of the first embodiment of the present invention.

[0038] FIG4 is a bottom view of the first embodiment of the present invention.

[0039] FIG5 is a cross-sectional view of the first embodiment of the present invention.

[0040] FIG6 is an enlarged view of the structure at point A in FIG5 .

[0041] FIG7 is a schematic diagram of the three-dimensional structure of the hard disk and the elastic unit in the first embodiment of the present invention.

[0042] FIG8 is a schematic diagram of the cross-section structure of the hard disk in the first embodiment of the present invention.

[0043] FIG9 is a partial cross-sectional view of the cooperation between the polishing head body and the hard disk in the second embodiment of the present invention.

[0044] FIG10 is a cross-sectional view of a third embodiment of the present invention.

[0045] FIG11 is a cross-sectional view of the third embodiment of the present invention, in which the retaining ring is not shown.

[0046] FIG12 is a schematic diagram of a partial three-dimensional structure of the third embodiment of the present invention.

[0047] FIG13 is a cross-sectional view 1 of the fourth embodiment of the present invention.

[0048] FIG14 is a second cross-sectional view of the fourth embodiment of the present invention.

[0049] FIG15 is a cross-sectional view of a fifth embodiment of the present invention.

[0050] FIG16 is a first schematic diagram of a partial three-dimensional structure of the fifth embodiment of the present invention.

[0051] FIG17 is a second schematic diagram of a partial three-dimensional structure of the fifth embodiment of the present invention.

[0052] FIG18 is a cross-sectional view of a sixth embodiment of the present invention.

[0053] FIG19 is a first schematic diagram of the matching structure of the hard disk, wafer substrate, and edge limiter in the seventh embodiment of the present invention.

[0054] FIG20 is a second schematic diagram of the matching structure of the hard disk, wafer substrate, and edge limiter in the seventh embodiment of the present invention.

[0055] FIG21 is a third schematic diagram of the matching structure of the hard disk, wafer substrate, and edge limiter in the seventh embodiment of the present invention.

[0056] FIG22 is a fourth schematic diagram of the matching structure of the hard disk, wafer substrate, and edge limiter in the seventh embodiment of the present invention.

[0057] FIG23 is a bottom view of the conductive cloth in the eighth embodiment of the present invention.

[0058] Among them, 1-polishing head body, 11-guide cylinder, 12-radial movable gap, 13-first air cavity, 2-hard disk, 21-air hole, 22-third air cavity, 221-conduit, 23-guide sleeve, 24-guide rod, 26-fourth air cavity, 27-air path, 28-conductive cloth, 281-air hole on the conductive cloth, 3-elastic unit, 4-second air cavity, 41-gas input channel, 5-retaining ring, 51-groove, 61-driving pin, 62-driving groove, 7-edge limiter, 71-guide groove, 8-wafer substrate, 81-wafer substrate cutting edge. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the solutions of the present invention, the following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0060] Example 1

[0061] As shown in Figures 1-7, a chemical mechanical polishing and planarization system includes at least a polishing head. The polishing head comprises a polishing head body 1, a hard disk 2, an elastic unit 3 connected to the polishing head body 1 and the hard disk 2, respectively, and a retaining ring 5 located below the polishing head body 1. A first air cavity 13 is formed within the polishing head body 1 to control the vertical movement and stroke of the polishing head body 1, thereby driving the hard disk 2 and wafer substrate up and down.

[0062] The hard disk 2 refers to a conductive disk made of a hard material, such as metal, conductive material or other conductive material with rigidity. The metal can be specifically aluminum, titanium, stainless steel, and other conductive materials can be conductive ceramics, graphite, etc. The above materials are all conductive materials, or the surface of the hard disk 2 is treated with conductive materials, so that the hard disk 2 can form a conductive circuit required for electrochemical mechanical polishing and flattening with the wafer substrate, polishing table, and power supply. The power is transmitted to the hard disk 2 and then to the wafer substrate for surface modification, and then mechanical polishing is performed.

[0063] In electrochemical mechanical polishing and planarization of wafer substrates, the circuit can be directly connected to the hard disk 2 from the electrode, or the circuit can be connected to the hard disk 2 from the elastic unit 3, or the circuit can be connected to the hard disk 2 from the polishing head body 1, without specific limitation.

[0064] The lower surface of the hard disk 2 lies at least partially in the same plane. In this embodiment, the lower surface of the hard disk 2 is entirely horizontal. Of course, in other embodiments, the horizontal portion of the hard disk 2 may be thickened or thinned in specific areas based on the thickness topography of the wafer substrate, thereby creating nanometer- to micrometer-scale height differences between different areas. In other embodiments, the side surfaces of the hard disk 2 may be treated with insulation and chamfering. Insulation treatments include, but are not limited to, hard anodizing and surface coating.

[0065] Of course, in other embodiments, the hard disk 2 may also be made of a non-conductive material, in which case it is used for chemical mechanical polishing of wafer substrates.

[0066] The upper surface of the hard disk 2 is airtight, and the lower surface of the hard disk 2 is at least partially horizontal, and a plurality of air holes 21 are provided on the horizontal portion of the lower surface. A third air cavity 22 is provided inside the hard disk 2, which is connected to the air holes 21. The third air cavity 22 must be connected in a sealed manner to prevent the polishing liquid from leaking and contaminating the polishing head. The remaining functions can be achieved by any connection method that does not affect the internal environment of the polishing head, such as air pipe connection, screw plus sealing ring connection of the body itself, flexible membrane cavity design, and other sealing designs. This can be achieved with existing technology and will not be repeated here. The diameter of the air holes 21 is 0.1-3mm, and the total area of ​​all the air holes 21 accounts for 0.1-5% of the lower surface area of ​​the hard disk 2. When the third air cavity 22 forms a negative pressure, the lower surface of the hard disk 2, more precisely the horizontal portion of the lower surface, can directly contact and adsorb the wafer substrate.

[0067] In this embodiment, all the air holes 21 are connected. As shown in FIG8 , radially staggered and connected air channels 27 are formed inside the hard disk 2. The air channels 27 are connected to the third air cavity 22. The air holes 21 are correspondingly arranged in the area where the air channels 27 are located. Therefore, the negative pressure formed by all the air holes 21 is relatively balanced.

[0068] One of the judgment logics for whether the wafer substrate is loaded on the polishing head body 1 is to perform a pressure holding test after evacuating the third air cavity 22 to detect the vacuum condition of the third air cavity 22. If the negative pressure is maintained, the wafer substrate is on the polishing head body 1; otherwise, the wafer substrate is not on the polishing head body 1.

[0069] The retaining ring 5 is an annular component that can contact the polishing pad, and the hard disk 2 moves within the area defined by the retaining ring 5 .

[0070] The elastic unit 3 is made of an elastic material and has a roughly annular structure. One side of the elastic unit 3 is connected to the outer ring of the hard disk 2, and the other side is fixedly connected between the polishing head body 1 and the retaining ring 5. The elastic unit 3, the polishing head body 1, and the hard disk 2 are arranged to form a second air cavity 4. The pressure in the second air cavity 4 is controllable, so by adjusting the pressure in the second air cavity 4, the elastic unit 3 can be driven to move flexibly, thereby assisting the hard disk 2 and the wafer substrate to float, thereby realizing electrochemical mechanical polishing and flattening of the wafer substrate. Here, the floating of the hard disk 2 and the wafer substrate refers to the use of the elastic unit 3 to improve the movement of the hard disk 2 and the wafer substrate under the premise of mechanical drive of the polishing head body 1 and the hard disk 2, which includes up and down floating and radial floating. The method for controlling the pressure in the second air cavity 4 can be achieved by the existing technology and will not be repeated here.

[0071] The sealing formation and pressure control of the second air cavity 4 can be achieved with existing technology and will not be described in detail.

[0072] The present invention changes the traditional structure of using a hard support plate and a flexible membrane to absorb the wafer substrate. Instead, the wafer substrate is directly absorbed by the hard plate 2. Based on the existing drive structure, the elastic unit 3, under the change of air pressure in the second air chamber 4, assists the hard plate 2 and the wafer substrate in rotating, lifting, swinging, and other movements within the retaining ring 5. In other words, the hard plate 2 and the wafer substrate float up and down and radially, achieving electrochemical mechanical polishing and planarization of the wafer substrate. The hard plate 2 can exert excellent electrical and thermal conductivity. During the electrochemical mechanical polishing and planarization process, the polishing liquid and heat involved in the process will not adversely affect the hard plate 2. It also does not have the poor electrical conductivity, easy corrosion, and poor stability of the flexible membrane in the traditional structure.

[0073] Example 2

[0074] In the first embodiment, the movement of the hard disk 2 and the wafer substrate is achieved by the existing mechanical drive structure, and the elastic unit 3 assists the hard disk 2 and the wafer substrate to float. In this embodiment, a new mechanical drive structure is adopted.

[0075] As shown in FIG9 , in this embodiment, the central axis of the polishing head body 1 extends in the direction of the hard disk 2 to form a guide cylinder 11, and the side of the hard disk 2 facing away from the wafer substrate forms a guide sleeve 23. The guide sleeve 23 is concentric and coaxial with the hard disk 2, and the guide cylinder 11 extends vertically into the guide sleeve 23, with a radial movable gap 12 between the two. The radial movable gap 12 here refers to the outer diameter of the guide cylinder 11 being smaller than the inner diameter of the guide sleeve 23. Therefore, when the guide cylinder 11 is inserted into the guide sleeve 23, while the elastic unit 3 drives the hard disk 2 to move flexibly, the movement of the guide cylinder 11 can also drive the guide sleeve 23. That is, a mechanical limit fit can be achieved between the polishing head body 1 and the hard disk 2, making the movement of the hard disk 2 more controllable.

[0076] Of course, in other embodiments, the guide sleeve 23 may be vertically extended into the guide cylinder 11, and a radial movable gap 12 may exist between the two.

[0077] Example 3

[0078] As shown in FIG. 10 to FIG. 12 , the polishing head body 1 includes a fourth air cavity 26 . The fourth air cavity 26 is located above the hard disk 2 , and the air pressure in the fourth air cavity 26 is variable, thereby pressurizing or depressurizing the hard disk 2 .

[0079] Specifically, the fourth air cavity 26 may be located above the central area of ​​the hard disk 2 , in which case it is a hemispherical cavity; or, the fourth air cavity 26 may be an annular or disc-shaped air cavity located above and concentric with the hard disk 2 .

[0080] In this embodiment, the fourth air cavity 26 is a circular cavity or an annular cavity above the hard disk 2. When inflated, the hard disk can press down the hard disk 2, and the downward pressure can be flexibly adjusted.

[0081] The pressure control of the fourth air cavity 26 can be achieved by existing technology and will not be described in detail.

[0082] Of course, multiple fourth air cavities can also be set up to achieve directional pressurization or decompression of the hard disk 2, and then achieve directional pressurization or decompression of specific areas of the wafer substrate. One of the functions of this cavity is to control the regional pressure of the wafer substrate, and the other is to further improve the stability of the polishing head through multi-cavity pressurization.

[0083] Example 4

[0084] On the basis of the second embodiment, one of the guide cylinder 11 and the guide sleeve 23 is provided with at least one driving pin 61, and the other is provided with a driving groove 62. The driving pin 61 extends horizontally into the driving groove 62, and there is a circumferential movable gap between the two.

[0085] Specifically, as shown in Figures 13-14, a drive pin 61 is formed on the outer periphery of the guide cylinder 11. In this embodiment, there are multiple drive pins 61, which are evenly spaced along the outer periphery of the guide cylinder 11. Of course, in other embodiments, the number of drive pins 61 can also be one or two radially symmetrically arranged, and there is no specific limitation.

[0086] The guide sleeve 23 is formed with driving grooves 62 , the number of which is the same as the number of the driving pins 61 , and the driving grooves 62 are also evenly spaced along the circumference of the guide sleeve 23 .

[0087] When the polishing head body 1 and the hard disk 2 are assembled, the drive pin 61 is inserted into the drive slot 62. The width of the drive pin 61 is smaller than the width of the drive slot 62, thereby creating a circumferential clearance between the two. This allows the drive pin 61 to oscillate circumferentially within the drive slot 62. This allows the elastic unit 3 to drive the hard disk 2 to move flexibly, achieving mechanical positional fit between the polishing head body 1 and the hard disk 2. Furthermore, the drive pin 61 and the drive slot 62 enable the polishing head body 1 to mechanically drive the hard disk 2, making the electrochemical mechanical polishing and planarization of the wafer substrate by the hard disk 2 more efficient.

[0088] By utilizing the driving pin 61 and the driving slot 62 to realize hard driving and the elastic unit 3 to assist the hard disk 2 in overcoming slight disturbances, the activities of the hard disk 2 and the wafer substrate are more controllable, the process stability is higher, and thus the electrochemical mechanical polishing and planarization or chemical mechanical polishing process is more controllable.

[0089] Example 5

[0090] In this embodiment, the hard disk 2 is provided with a guide rod 24 , which extends vertically upward from the center of the polishing head body 1 , and a radial movable gap exists between the guide rod 24 and the polishing head body 1 .

[0091] A guide cylinder 11 is formed on the side of the central axis of the polishing head body 1 facing the hard disk 2. One of the guide cylinder 11 and the guide rod 24 is provided with at least one driving pin 61, and the other is provided with a driving groove 62. The driving pin 61 extends into the driving groove 62, and there is a circumferential movable gap between the two.

[0092] Specifically, as shown in Figures 15 to 17, three drive pins 61 are evenly spaced along the circumferential direction on the outer wall of the guide rod 24, and the inner ring of the guide cylinder 11 is hollowed out to form three drive grooves 62. The width of the drive groove 62 is greater than the width of the drive pin 61, so that when the drive pin 61 is inserted into the drive groove 62, there is a circumferential movable gap between the two, that is, the drive pin 61 can swing circumferentially in the drive groove 62.

[0093] Thus, while the elastic unit 3 drives the hard disk 2 to move flexibly and mechanical limiting cooperation is achieved between the polishing head body 1 and the hard disk 2, the polishing head body 1 can also mechanically drive the hard disk 2 through the driving pin 61 and the driving groove 62, making the hard disk 2 drive the wafer substrate to perform electrochemical mechanical polishing and flattening more effective.

[0094] Meanwhile, the guide rod 24 can be hollow, with a conduit 221 extending therethrough. This conduit 221 communicates with the third air chamber 22. Because the negative pressure in the third air chamber 22 draws polishing liquid into the conduit 221 when the wafer substrate is attracted, the conduit 221 of the third air chamber 22 is flushed at the end of each polishing operation, simultaneously flushing the backside of the wafer substrate. The conduit 221 is connected to the air circuit control system via a conductive slip ring through the polishing head body 1, where it performs water-gas separation.

[0095] Example 6

[0096] In the above-mentioned embodiments 1 to 5, there is no limitation on the gas input form of the second gas cavity 4 , nor on whether the second gas cavity 4 is divided into a plurality of sub-gas cavities.

[0097] As shown in Figure 18, unlike the fifth embodiment in which the second air cavity 4 has only one gas input channel 41, in this embodiment, the second air cavity 4 has two gas input channels 41, which are symmetrically distributed along the radial direction. Therefore, the gas input of the second air cavity 4 is more uniform and more controllable, and the driving of the hard disk 2 is more flexible and effective.

[0098] Example 7

[0099] For some conductive wafer substrates 8 with irregular shapes, such as a 6-inch silicon carbide wafer substrate 8 with a cut edge 81, there is no conductive wafer substrate 8 medium at the cut edge 81. After the hard disk 2 absorbs the wafer substrate 8, part of its area is still exposed to the outside world. The hard disk 2 will be directly energized and oxidized, affecting the life of the hard disk 2. In addition, as the wafer substrate 8 rotates, swings, and rotates with the polishing head body 1, there will be relative sliding between the cut edge 81 of the wafer substrate 8 and the hard disk 2, causing a circle of electrical oxidation at the edge. Therefore, it is necessary to design a limit for the irregular-shaped conductive wafer substrate 8 to limit the rotation of the wafer substrate 8 inside the polishing head body 1.

[0100] As shown in Figure 19, by adding a limit piece 7 on the surface of the hard disk 2, the limit piece 7 is made of insulating material and can be attached or embedded in the hard disk 2, that is, the limit piece 7 can be respectively against the cut edge 81 of the wafer substrate and the inner wall of the retaining ring 5. The overall height of the limit piece 7 should be flush with the height of the wafer substrate 8 when loaded, or slightly lower than the lower surface of the wafer substrate 8, and the height difference is ≤0.3mm.

[0101] In order to prevent the edge limiting member 7 from colliding with the edge vertex of the cutting edge 81, the overall length of the edge limiting member 7 can be shortened, and the edge can be rounded, as shown in FIG. 20 .

[0102] In order to allow the polishing liquid to better enter the polishing head body 1 through the groove 51 of the retaining ring 5, the edge limiter 7 can also be provided with a guide groove 71. The angle of the guide groove 71 is on the extension line of the groove 51 of the retaining ring 5, and the width of the guide groove 71 is consistent with the width of the groove 51 of the retaining ring 5, as shown in FIG21.

[0103] As shown in FIG. 22 , the edge limiting member 7 may also be simplified into a multi-point limiting structure, with the number of points N≥2. In this case, the edge limiting member 7 abuts against the cut edge 81 of the wafer substrate.

[0104] Example 8

[0105] In this embodiment, a flexible conductive cloth 28 is attached to the lower surface of the hard disk 2, and its resistivity is less than 10 -3 As shown in FIG23 , the flexible conductive fabric 28 includes air holes 281 that match the positions of at least some of the air holes 21 of the hard disk 2 . This allows for a smoother air path when the air cavity 3 is pressurized or vacuumed, facilitating better wafer adsorption during vacuum processing in the air cavity 3 .

[0106] Of course, the flexible conductive cloth 28 can also be simply flexible cloth, without the need for conductive functionality. Specifically, the flexible cloth is a non-conductive material. In this case, the pores of the flexible cloth are filled with an electrolyte, thereby establishing conductive communication between the wafer substrate and the polishing head body 1. Specifically, during the electrochemical polishing process, the electrolyte fills the flexible cloth, allowing the electrolyte to connect the back surface of the wafer substrate and the wafer-carrying surface of the polishing head body 1, forming a circuit.

[0107] Specifically, some of the pores may be filled with electrolyte, and some of the pores may be used only for adsorbing the wafer substrate; or a single pore may simultaneously play the function of adsorbing the wafer substrate and conducting the power circuit, that is, the electrolyte flows through the inner wall of the pore to realize the function of the electrolyte connecting the back side of the wafer substrate and the wafer carrying surface of the polishing head body 1 to form a circuit.

[0108] Of course, the flexible cloth can be a woven fabric, a foamed polymer, or a sponge structure with interconnected tops and bottoms. The flexible cloth can be non-conductive and flexible enough to avoid abrasion on the backside of the wafer substrate. There are no specific restrictions.

[0109] The other structures are the same as those in any of the embodiments 1 to 5 and will not be described in detail.

[0110] Embodiment 9

[0111] In this embodiment, a waterproof and breathable layer is attached to the lower surface of the hard disk 2. This waterproof and breathable layer allows gas to pass through under vacuum and pressurization conditions, but does not support moisture adsorption and passage, thereby ensuring that chemicals and moisture are not absorbed during negative pressure operation of the wafer substrate. The waterproof and breathable layer can be applied to the entire surface or only to the air holes 21 on the lower surface of the hard disk 2. When the entire surface is applied, the waterproof and breathable layer needs to be conductive. When the air holes 21 are applied, the edges of the waterproof and breathable layer on both sides need to be bonded with conductive adhesive.

[0112] The other structures are the same as those in any of the embodiments 1 to 5 and will not be described in detail.

[0113] The above specific embodiments are used to illustrate the present invention rather than to limit the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A chemical mechanical polishing and planarization system, characterized in that, At least includes a polishing head, which includes: Polishing head body (1); A hard disk (2), wherein at least part of its lower surface is located in the same plane, and a plurality of air holes (21) are provided in the lower surface part located in the same plane, and a third air cavity (22) connected to the air holes (21) is provided inside the hard disk (2); The elastic unit (3) is at least partially annular in structure and is connected to the polishing head body (1) and the hard disk (2) respectively, and the polishing head body (1), the elastic unit (3) and the hard disk (2) are arranged to form a second air cavity (4); A retaining ring (5), located below the polishing head body (1), is an annular component that can contact the polishing pad, and the hard disk (2) moves within the area defined by the retaining ring (5); When the third air cavity (22) is in a negative pressure state, the lower surface of the hard disk (2) can contact and adsorb the wafer substrate, and the pressure in the second air cavity (4) can be controlled to drive the elastic unit (3) to move flexibly, thereby assisting the hard disk (2) and the wafer substrate to float, thereby achieving chemical mechanical polishing of the wafer substrate.

2. The chemical mechanical polishing and planarization system according to claim 1, wherein: The hard disk (2) is made of a conductive material or has a conductive surface treatment to achieve electrochemical mechanical polishing and flattening of the wafer substrate.

3. The chemical mechanical polishing and planarization system according to claim 2, wherein: In electrochemical mechanical polishing and flattening of a wafer substrate, a circuit is connected from an elastic unit (3) to a hard disk (2), or the circuit is directly connected from an electrode to the hard disk (2), or the circuit is connected from a polishing head body (1) to the hard disk (2).

4. The chemical mechanical polishing and planarization system according to claim 1, wherein: The horizontal portion of the lower surface of the hard disk (2); or, the horizontal portion of the lower surface of the hard disk (2) forms a thickened area or a thinned area to form a height difference from nanometer level to micrometer level.

5. The chemical mechanical polishing and planarization system according to claim 1, wherein: The elastic unit (3) is made of an elastic material, one side of its annular structure is connected to the outer ring of the hard disk (2), and the other side is fixedly connected between the polishing head body (1) and the retaining ring (5).

6. The chemical mechanical polishing and planarization system according to claim 1 or 2 or 3 or 5, characterized in that: The central axis of the polishing head body (1) extends in the direction of the hard disk (2) to form a guide cylinder (11), and the side of the hard disk (2) facing away from the wafer substrate forms a guide sleeve (23), the guide sleeve (23) is coaxial with the hard disk (2), the guide cylinder (11) extends into the guide sleeve (23), or the guide sleeve (23) extends into the guide cylinder (11), and there is a radial movable gap (12) between the two.

7. The chemical mechanical polishing and planarization system according to claim 6, characterized in that: One of the guide cylinder (11) and the guide sleeve (23) is provided with at least one driving pin (61), and the other is provided with a driving groove (62). The driving pin (61) extends into the driving groove (62), and there is a circumferential movable gap between the two.

8. The chemical mechanical polishing and planarization system according to claim 7, wherein: The number of the driving pins (61) and the number of the driving slots (62) are equal.

9. The chemical mechanical polishing and planarization system according to claim 1 or 2 or 3 or 5, characterized in that: The hard disk (2) is provided with a guide rod (24), and the guide rod (24) vertically extends upward from the center of the polishing head body (1).

10. The chemical mechanical polishing and planarization system according to claim 9, wherein: A conduit (221) is provided inside the guide rod (24), and the conduit (221) is communicated with the third air cavity (22).

11. The chemical mechanical polishing and planarization system according to claim 9, wherein: A guide cylinder (11) extends from the central axis of the polishing head body (1) towards the direction where the hard disk (2) is located. At least one driving pin (61) is provided on one of the guide cylinder (11) and the guide rod (24), and a driving groove (62) is provided on the other. The driving pin (61) extends into the driving groove (62), and there is a circumferential movement gap between the two.

12. The chemical mechanical polishing and planarization system according to claim 1 or 2 or 3 or 5, characterized in that: A flexible cloth is attached to the lower surface of the hard disk (2), which contains air holes, and the positions of the air holes match at least part of the air holes of the hard disk.

13. The chemical mechanical polishing and planarization system according to claim 12, wherein: The flexible cloth is a conductive flexible cloth.

14. The chemical mechanical polishing and planarization system according to claim 12, wherein: The flexible cloth is made of a non-conductive material, and the air holes of the flexible cloth are filled with an electrolyte so that the wafer substrate and the polishing head body (1) are electrically connected.

15. The chemical mechanical polishing and planarization system according to claim 12, wherein: The flexible cloth has a sponge structure, or the flexible cloth is a foamed polymer.

16. The chemical mechanical polishing and planarization system according to claim 1, wherein: The polishing head body (1) includes at least one fourth air chamber (26), which is located above the hard disk (2), and the air pressure in the fourth air chamber (26) is variable to pressurize or depressurize a specific area of the hard disk (2).

17. The chemical mechanical polishing and planarization system according to claim 16, wherein: The fourth air chamber (26) is located above the central area of the hard disk (2), or the fourth air chamber (26) is an annular or disc-shaped air chamber located above the hard disk (2) and concentric with it.

18. The chemical mechanical polishing and planarization system according to claim 1 or 2 or 3 or 5, characterized in that: The polishing head body (1) forms a first air chamber (13), which is used to control the up and down stroke of part of the polishing head body (1).

19. The chemical mechanical polishing and planarization system according to claim 1 or 2 or 3 or 5, characterized in that: The diameter of the air holes (21) is 0.1 - 3 mm, and the total area accounts for 0.1 - 5% of the lower surface area of the hard disk (2).

20. The chemical mechanical polishing and planarization system according to claim 1 or 2 or 3 or 5, characterized in that: A waterproof and breathable layer is provided on the lower surface of the hard disk (2).

21. The chemical mechanical polishing and planarization system according to claim 1 or 2 or 3 or 5, characterized in that: A limiting edge member (7) is provided on the hard disk (2), which can respectively abut against the cutting edge (81) of the wafer substrate and the inner wall of the retaining ring (5), or it can abut against the cutting edge (81) of the wafer substrate.

22. The chemical mechanical polishing and planarization system according to claim 21, wherein: The retaining ring (5) is provided with a groove (51) for the polishing liquid to enter and exit, and the limiting edge member (7) is provided with a guiding groove (71) that can communicate with the groove (51); the limiting edge member (7) is made of an insulating material.

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