Chemical mechanical polishing and planarization system

Abstract

The utility model discloses a chemical mechanical polishing and planarization system, which at least comprises a polishing head. A plurality of air holes are formed in the lower surface of the hard disc, and a third air cavity communicated with the air holes is formed in the hard disc; at least part of the elastic unit is of an annular structure, the elastic unit is connected with the polishing head body and the hard disc, and a second air cavity is defined by the polishing head body, the elastic unit and the hard disc; a retaining ring; when the third air cavity is in a negative pressure state, the lower surface of the hard disc can make contact with and adsorb the wafer substrate, and the pressure in the second air cavity is controllable, so that the elastic unit is driven to flexibly move, the hard disc and the wafer substrate are assisted to float, and chemical mechanical polishing of the wafer substrate is achieved. The hard drive in the hard disc solves the problem that when the flexible film drives the wafer substrate to polish, the flexible film is pulled to cause fracture or elastic modulus change under the severe polishing condition, and the service life of the flexible piece is prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of semiconductor integrated circuit chip manufacturing, in particular to a chemical mechanical polishing and flattening system. Background Art

[0002] The manufacturing process of wafer substrates and semiconductor devices includes processes such as polishing and surface flattening. Mechanical polishing, chemical mechanical polishing or flattening are usually used. The wafer carrier (polishing head) applies pressure to the back of the wafer, and the pressure, polishing head speed, polishing disk speed, polishing liquid flow rate and other parameters are controlled to polish or flatten the front surface of the wafer substrate or the thin film surface on the polishing pad. Compared with mechanical polishing, chemical mechanical polishing and flattening can achieve higher polishing or flattening efficiency and better polishing or flattening effects, including higher flatness and lower defectivity, by adjusting the formula of the polishing liquid. There are two main types of pressure applied by the polishing head to the wafer substrate. One of them 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. The pressure distribution on the wafer substrate is adjusted by controlling the pressure of the flexible membrane cavity, so that the regional thickness control of the wafer substrate can be achieved. 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 is adjustable and the local area can be modified, but it has little effect on the overall thickness change of the wafer substrate; while 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 as 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. The surface chemical reaction rate is increased through the precise control of the circuit system, thereby improving the mechanical polishing and planarization efficiency. The polishing head in the commonly used embodiment is mainly of an 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 risks 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, so there is an uneven current size and distribution from the center to the edge on the polishing platform. Second, the vacuum conductive suction cup head adsorbs the wafer to fix it. Through the movement of the mobile polishing platform, the relative movement stroke between the wafer and the polishing disc is small, which will lead to the non-uniformity of the electrochemical reaction on the wafer. In addition, this conductive suction cup head is often a hard disc loaded by the spindle. The rigid conductive disc does not have the in-plane pressure adjustment control, so it cannot act on the wafer surface to control the in-plane uniformity. In addition, there is also an electropolishing head that loads the electrode to the outer circumference of the wafer, and forms a planar conduction of the wafer polishing surface through multi-point contact, but the electrode design is complex and wears in contact with the outer circumference of the wafer. The two conventional chemical mechanical polishing and flattening applications mentioned above are flexible cavity pressurized polishing heads, and hard disc polishing heads (wafer substrates are attached to the lower surface of the hard disc through wax sealing / film treatment). In the above two methods, the flexible rubber airbag and the hard disc wax sealing / film treatment are both electrically insulating or weakly conductive, and cannot achieve the ampere-level current on 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 achieve multiple tasks such as wafer substrate loading, unloading, and pressurization, and on the other hand, the need to meet the requirements of high electrical conductivity.

[0004] Based on the above background technology, conventional chemical mechanical polishing and planarization polishing heads cannot take into account both the overall thickness change optimization and the local area modifiable functionality. The technical routes of the above two polishing heads can be combined to develop a new type of polishing head that can achieve local adjustability by adding flexible cavity control on the basis of achieving overall thickness adjustability based on the hard disk. In addition, for electrochemical polishing and planarization technology, the hard disk of the above polishing head is treated with conductivity, thereby realizing the application of the new type of polishing head in electrochemical polishing and planarization technology. Utility Model Content

[0005] In order to overcome the shortcomings of the prior art, the utility model provides a chemical mechanical polishing and planarization system. The hard disk can realize loading and unloading of wafer substrates through pressure control of a third cavity, and can also adsorb or not adsorb the wafer substrate. The hard disk is controlled to move with the wafer substrate by the cooperation of an elastic unit and a second air cavity, thereby ensuring effective chemical mechanical polishing and planarization of the wafer substrate and extending the service life of the polishing head.

[0006] The technical solution adopted by the utility model to solve the technical problem is: a chemical mechanical polishing and planarization system, comprising at least a polishing head, the polishing head comprising:

[0007] Polishing head body;

[0008] A hard disk, wherein at least part of its lower surface is located in the same plane, and a plurality of air holes are opened in the part of the lower surface located in the same plane, and a third air cavity connected to the air holes is opened inside the hard disk;

[0009] The elastic unit is at least partially annular and connected to the polishing head body and the hard disk, respectively, and the polishing head body, the elastic unit and the hard disk are surrounded to form a second air cavity;

[0010] A retaining ring, an annular component that can contact the polishing pad, wherein the hard disk moves within the area defined by the retaining ring;

[0011] 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 the wafer substrate to float, thereby realizing chemical mechanical polishing of the wafer substrate.

[0012] 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.

[0013] 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 from the electrode to the hard disk, or the circuit is connected from the polishing head body to the hard disk.

[0014] Further, 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.

[0015] Furthermore, the elastic unit is made of an 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.

[0016] 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 away from the wafer substrate forms a guide sleeve, which is concentric and coaxial with the hard disk, and 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.

[0017] 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.

[0018] Furthermore, the number of the driving pins and the number of the driving slots are equal.

[0019] Furthermore, the hard disk is provided with a guide rod, and the guide rod vertically extends upward from the center of the polishing head body.

[0020] Furthermore, a conduit is inserted into the guide rod, and the conduit is communicated with the third air cavity.

[0021] Furthermore, the central axis of the polishing head body extends toward the direction of 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.

[0022] 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.

[0023] Furthermore, the flexible cloth is a conductive flexible cloth.

[0024] 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.

[0025] Furthermore, the flexible cloth is a sponge structure, or the flexible cloth is a foamed polymer.

[0026] Furthermore, the polishing head body includes at least one fourth air cavity, which is 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.

[0027] Further, 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 the hard disk and concentric therewith.

[0028] Furthermore, the polishing head body is formed with a first air cavity, which is used to control the up and down travel of the polishing head body.

[0029] 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.

[0030] Furthermore, a waterproof and breathable layer is provided on the lower surface of the hard disk.

[0031] Furthermore, the hard disk is provided with an edge limiting piece, 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.

[0032] 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.

[0033] The beneficial effects of the utility model 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, the fluctuation of its force balance state will affect the polishing speed, and the polishing efficiency will be adversely affected, and 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 return of the flexible membrane will not cause The scraping of 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 process 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 achieve modification of the local area while optimizing the total thickness change of the wafer substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the front view of the first embodiment of the utility model.

[0035] Figure 2 The three-dimensional structure of the first embodiment of the utility model is shown in FIG. Figure 1 .

[0036] Figure 3 The three-dimensional structure of the first embodiment of the utility model is shown in FIG. Figure 2 .

[0037] Figure 4 It is a bottom view of the first embodiment of the utility model.

[0038] Figure 5 It is a cross-sectional view of the first embodiment of the present utility model.

[0039] Figure 6 for Figure 5 A magnified view of the structure in Figure 2.

[0040] Figure 7 It is a schematic diagram of the three-dimensional structure of the hard disk and the elastic unit in the first embodiment of the utility model.

[0041] Figure 8 It is a schematic diagram of the cutaway structure of the hard disk in the first embodiment of the utility model.

[0042] Fig. 9 It is a partial cross-sectional view of the cooperation between the polishing head body and the hard disk in the second embodiment of the utility model.

[0043] Fig.10 It is a cross-sectional view of the third embodiment of the present utility model.

[0044] Fig.11 This is a cross-sectional view of the third embodiment of the present invention, in which the retaining ring is not shown.

[0045] Fig.12 It is a schematic diagram of the partial three-dimensional structure of the third embodiment of the utility model.

[0046] Fig.13 This is a cross-sectional view of the fourth embodiment of the utility model Figure 1 .

[0047] Fig.14 This is a cross-sectional view of the fourth embodiment of the utility model Figure 2 .

[0048] Fig.15 It is a cross-sectional view of the fifth embodiment of the present utility model.

[0049] Fig.16 The partial three-dimensional structure of the fifth embodiment of the utility model is shown in FIG. Figure 1 .

[0050] Fig.17 The partial three-dimensional structure of the fifth embodiment of the utility model is shown in FIG. Figure 2 .

[0051] Fig.18 It is a cross-sectional view of the sixth embodiment of the present utility model.

[0052] Fig.19 Schematic diagram of the matching structure of the hard disk, wafer substrate and edge limiter in the seventh embodiment of the present utility model Figure 1 .

[0053] Fig. 20 Schematic diagram of the matching structure of the hard disk, wafer substrate and edge limiter in the seventh embodiment of the present utility model Figure 2 .

[0054] Fig.21 Schematic diagram of the matching structure of the hard disk, wafer substrate and edge limiter in the seventh embodiment of the present utility model Figure 3 .

[0055] Fig. 22 Schematic diagram of the matching structure of the hard disk, wafer substrate and edge limiter in the seventh embodiment of the present utility model Figure 4 .

[0056] Fig.23 This is a bottom view of the conductive fabric in the eighth embodiment of the present utility model.

[0057] 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

[0058] In order to enable those skilled in the art to better understand the solution of the utility model, the following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0059] Embodiment 1

[0060] like Figure 1-Figure 7As shown, a chemical mechanical polishing and planarization system at least includes a polishing head, which includes 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 in the polishing head body 1, which is used to control the up and down lifting and lifting stroke of the polishing head body 1, thereby driving the hard disk 2 and the wafer substrate to lift up and down.

[0061] 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 may be aluminum, titanium, stainless steel, and other conductive materials may 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.

[0062] In electrochemical mechanical polishing and planarization of wafer substrates, the circuit can be directly connected from the electrode to the hard disk 2, or the circuit can be connected from the elastic unit 3 to the hard disk 2, or the circuit can be connected from the polishing head body 1 to the hard disk 2, without specific limitation.

[0063] The lower surface of the hard disk 2 is at least partially located in the same plane. In this embodiment, the lower surface of the hard disk 2 is horizontal. Of course, in other embodiments, the horizontal portion of the hard disk 2 can also be thickened or thinned in a specific area according to the thickness morphology of the wafer substrate, that is, a thickened area or a thinned area is formed to form a height difference from nanometer to micrometer between different areas. In other embodiments, the side of the hard disk 2 can be treated with insulation and chamfering, wherein the insulation treatment includes but is not limited to hard oxidation, surface coating, etc.

[0064] Of course, in other embodiments, the hard disk 2 may also be made of a non-conductive material, in which case it is applied to chemical mechanical polishing of a wafer substrate.

[0065] The upper surface of the hard disk 2 is airtight, the lower surface of the hard disk 2 is at least partially horizontal, and a plurality of air holes 21 are provided in the horizontal portion of the lower surface. A third air cavity 22 connected to the air holes 21 is provided inside the hard disk 2. The third air cavity 22 must be connected in a closed manner to prevent the polishing liquid from leaking and contaminating the polishing head. The remaining functions can be achieved by any connection method without affecting the internal environment of the polishing head, such as air pipe connection, screw plus sealing ring connection of the machine body itself, flexible membrane cavity design and other sealing designs, which can be achieved by the existing technology and will not be repeated. The diameter of the air hole 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.

[0066] In this embodiment, all the air holes 21 are connected. Figure 8 As shown, radially staggered and connected air channels 27 are formed inside the hard disk 2, and 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, so the negative pressure formed by all the air holes 21 is relatively balanced.

[0067] One of the judgment logics for whether the wafer substrate is loaded onto 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.

[0068] 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 .

[0069] The elastic unit 3 refers to a structure made of elastic material, which is roughly annular, one side of which 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, and the hard disk 2 and the wafer substrate can be assisted to float, so as to realize the electrochemical mechanical polishing and flattening of the wafer substrate. Here, the floating of the hard disk 2 and the wafer substrate means that, under the premise of mechanical drive of the polishing head body 1 and the hard disk 2, the elastic unit 3 is used to improve the activities of the hard disk 2 and the wafer substrate, which activities include up and down floating and radial floating. The method for controlling the pressure in the second air cavity 4 can be realized by the existing technology and will not be repeated.

[0070] The sealing formation and pressure controllable of the second air cavity 4 can be achieved by the existing technology and will not be described in detail.

[0071] In the utility model, the conventional structure of using a hard support disk and a flexible film to absorb the wafer substrate is changed, and the wafer substrate is directly absorbed by the hard disk 2. On the basis of the existing driving structure, the elastic unit 3 assists the hard disk 2 and the wafer substrate to rotate, lift, swing, etc. in the retaining ring 5 under the change of the air pressure in the second air cavity 4, that is, the hard disk 2 and the wafer substrate float up and down and radially, so as to realize the electrochemical mechanical polishing and flattening of the wafer substrate. The hard disk 2 can exert good electrical conductivity and thermal conductivity, and in the process of electrochemical mechanical polishing and flattening, the polishing liquid and heat increase involved in the process will not have an adverse effect on the hard disk 2, nor will it be poor in electrical conductivity, easy to corrode, and poor in stability like the flexible film in the conventional structure.

[0072] Embodiment 2

[0073] In the first embodiment, the movement of the hard disk 2 and the wafer substrate is realized by the existing mechanical driving structure, and the elastic unit 3 assists the hard disk 2 and the wafer substrate to float. In this embodiment, a new mechanical driving structure is adopted.

[0074] like Fig. 9 As shown, 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, which is concentric and coaxial with the hard disk 2, and the guide cylinder 11 vertically extends into the guide sleeve 23, and there is a radial activity gap 12 between the two. Here, the radial activity gap 12 refers to the outer diameter of the guide cylinder 11 being smaller than the inner diameter of the guide sleeve 23, so that after 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 drive the guide sleeve 23, that is, the polishing head body 1 and the hard disk 2 can also achieve mechanical limit cooperation, so that the movement of the hard disk 2 is more controllable.

[0075] 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.

[0076] Embodiment 3

[0077] like Figure 10-12 As shown, the polishing head body 1 includes a fourth air cavity 26 , which 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 .

[0078] 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 is an annular or disc-shaped air cavity located above the hard disk 2 and concentric therewith.

[0079] 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.

[0080] The pressure control of the fourth air cavity 26 can be achieved by the existing technology and will not be described in detail.

[0081] 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.

[0082] Embodiment 4

[0083] 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.

[0084] Specifically, Figure 13-14 As shown, a driving pin 61 is formed on the outer periphery of the guide cylinder 11. In the present embodiment, there are multiple driving pins 61, which are evenly spaced along the outer periphery of the guide cylinder 11. Of course, in other embodiments, the number of driving pins 61 may be one or two radially symmetrically arranged, without any specific limitation.

[0085] 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 .

[0086] When the polishing head body 1 and the hard disk 2 are assembled, the driving pin 61 is inserted into the driving groove 62, and the width of the driving pin 61 is smaller than the width of the driving groove 62, so that there is a circumferential movable gap between the two, that is, the driving pin 61 can swing circumferentially in the driving groove 62. Therefore, while the elastic unit 3 drives the hard disk 2 to move flexibly and the mechanical limit fit between the polishing head body 1 and the hard disk 2 is achieved, the polishing head body 1 can also mechanically drive the hard disk 2 through the driving pin 61 and the driving groove 62, so that the activity of the hard disk 2 driving the wafer substrate to perform electrochemical mechanical polishing and planarization is more effective.

[0087] By using the driving pin 61 and the driving groove 62 to realize hard driving and the elastic unit 3 to assist the hard disk 2 to overcome 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.

[0088] Embodiment 5

[0089] In this embodiment, 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 , and a radial movable gap exists between the guide rod 24 and the polishing head body 1 .

[0090] A guide cylinder 11 is formed on one 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.

[0091] Specifically, Figure 15-17 As shown, the outer wall of the guide rod 24 is provided with three driving pins 61 evenly spaced along the circumferential direction, and the inner circle of the guide cylinder 11 is hollowed out to form three driving grooves 62. The width of the driving groove 62 is greater than the width of the driving pin 61. Therefore, when the driving pin 61 is inserted into the driving groove 62, there is a circumferential movable gap between the two, that is, the driving pin 61 can swing circumferentially in the driving groove 62.

[0092] Thus, while the elastic unit 3 drives the hard disk 2 to perform flexible movement 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.

[0093] At the same time, the guide rod 24 may be hollow in structure, and a conduit 221 is provided inside the guide rod 24, which is connected to the third air cavity 22. Since the negative pressure of the third air cavity 22 absorbs the polishing liquid into the conduit 221 when the wafer substrate is adsorbed, the conduit 221 of the third air cavity 22 is flushed at the end of each polishing, and the back of the wafer substrate is also flushed. The conduit 221 is connected to the gas path control system through the polishing head body 1 via a conductive slip ring, and water and gas separation is performed.

[0094] Embodiment 6

[0095] 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.

[0096] like Fig.18 As shown, unlike the fifth embodiment in which the second air cavity 4 has one gas input channel 41, in the present 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.

[0097] Embodiment 7

[0098] For some conductive wafer substrates 8 with irregular shapes, such as the 6-inch silicon carbide wafer substrate 8, there will be a cut edge 81. Since 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, which will affect the life of the hard disk 2. In addition, since the wafer substrate 8 rotates, swings, and the polishing disk 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 on the edge. Therefore, it is necessary to perform a limit design for the special-shaped conductive wafer substrate 8 to limit the rotation of the wafer substrate 8 inside the polishing head body 1.

[0099] like Fig.19 As shown, by adding an edge limiter 7 on the surface of the hard disk 2, the edge limiter 7 is made of insulating material and can be attached or embedded in the hard disk 2, that is, the edge limiter 7 can be respectively against the cut edge 81 of the wafer substrate and the inner wall of the retaining ring 5, and the overall height of the edge limiter 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.

[0100] 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, such as Fig. 20 shown.

[0101] 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. Fig.21 shown.

[0102] like Fig. 22 As shown, the edge limiting member 7 can also be simplified as 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.

[0103] Embodiment 8

[0104] 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 mΩ·cm. Fig.23 As shown, the flexible conductive cloth 28 includes air holes 281, and the air holes 281 match the positions of at least some of the air holes 21 of the hard disk 2, so that the air path is smoother when the air cavity 3 is pressurized or vacuum operated, which is beneficial for better adsorption of wafers when the air cavity 3 is vacuum treated.

[0105] Of course, the flexible conductive cloth 28 can also be just a flexible cloth without realizing the conductive function. That is, the flexible cloth is a non-conductive material. In this case, the pores of the flexible cloth are filled with electrolyte, so that the wafer substrate and the polishing head body 1 are conductively connected. That is, during the electrochemical polishing process, the flexible cloth is filled with electrolyte, so that the electrolyte connects the back side of the wafer substrate and the wafer bearing surface of the polishing head body 1 to form a circuit.

[0106] Specifically, some pores may be filled with electrolyte, and some pores may be used only for adsorbing wafer substrates; or a single pore may simultaneously play the function of adsorbing wafer substrates and conducting the electrical 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 with the wafer carrying surface of the polishing head body 1 to form a circuit.

[0107] Of course, the flexible cloth can be a foamed polymer, or a sponge structure with upper and lower connections, in addition to a woven cloth. The flexible cloth only needs to be non-conductive and have a certain degree of flexibility to ensure that it will not wear the back of the wafer substrate, and there is no specific limitation.

[0108] The other structures are the same as those of any of the embodiments 1 to 5 and will not be described in detail.

[0109] Embodiment 9

[0110] In this embodiment, a waterproof and breathable layer is attached to the lower surface of the hard disk 2. This waterproof and breathable layer supports gas passage under vacuum and pressurization conditions, but does not support moisture adsorption and passage, thereby ensuring that chemicals and moisture are not inhaled during negative pressure operation of the wafer substrate. The waterproof and breathable layer can be attached 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 attached, the waterproof and breathable layer needs to be conductive. When the air holes 21 are attached, the edges of the waterproof and breathable layer on both sides need to be bonded with conductive adhesive.

[0111] The other structures are the same as those of any of the embodiments 1 to 5 and will not be described in detail.

[0112] The above specific implementation modes are used to explain the present invention rather than to limit the present invention. Any modification and change 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), an annular component that can contact the polishing pad, wherein 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, 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), 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.

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), and contains air holes, which match the positions of at least some of the air holes of the hard disk.

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

14. The chemical mechanical polishing and planarization system according to claim 12, characterized in that: The flexible cloth is a non-conductive material, and the pores of the flexible cloth are filled with 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, characterized in that: The flexible cloth is a sponge structure, or the flexible cloth is a foamed polymer.

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

17. The chemical mechanical polishing and planarization system according to claim 16, characterized in that: The fourth air cavity (26) is located above the central area of ​​the hard disk (2), or the fourth air cavity (26) is an annular or disc-shaped air cavity located above the hard disk (2) and concentric therewith.

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) is formed with a first air cavity (13) which is used to control the up and down travel 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 pores (21) is 0.1-3 mm, and the total area thereof 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: The lower surface of the hard disk (2) is provided with a waterproof and breathable layer.

21. 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 an edge limiting member (7), which can respectively abut against the cut edge (81) of the wafer substrate and the inner wall of the retaining ring (5), or can abut against the cut edge (81) of the wafer substrate.

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

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