Chemical mechanical polishing and planarization system

Abstract

The invention discloses a chemical mechanical polishing and planarization system, which at least comprises a polishing head, and the polishing head comprises a polishing head body; 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; the retaining ring is positioned below the polishing head body; 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. According to the hard drive in the hard disc, the problem that when the flexible film drives the wafer substrate to be polished, under the severe polishing condition, the flexible film is pulled to cause fracture or elastic modulus change is solved, and the service life of the flexible piece is prolonged.

Description

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 manufacturing process of a wafer substrate and semiconductor devices includes processes such as polishing and surface planarization. Generally, techniques such as mechanical polishing, chemical mechanical polishing or planarization are adopted. By applying pressure to the back of the wafer through a wafer carrier head (polishing head), parameters such as pressure, polishing head rotation speed, polishing pad rotation speed, and polishing liquid flow rate are controlled to polish or planarize the front surface or thin film surface of the wafer substrate on the polishing pad. Compared with mechanical polishing, chemical mechanical polishing and planarization can generate chemical reactions on the wafer surface by adjusting the polishing liquid formula, achieving higher polishing or planarization efficiency, and at the same time achieving better polishing or planarization effects, including higher flatness, lower defect density, etc. The forms of pressure applied by the polishing head to the wafer substrate are mainly divided into two categories. One of them is flexible membrane air cavity pressurization. Briefly speaking, the flexible membrane directly contacting the wafer substrate can be a single cavity or multiple cavities. By controlling the pressure in the flexible membrane cavity, the pressure distribution acting on the wafer substrate can be adjusted, so as to achieve regional thickness control of the wafer substrate. The other is hard disk pressurization. What directly contacts the wafer substrate is a hard disk, which is driven by a hard guide rod. The hard guide rod directly gives a vertical downward pressure to the hard disk, acting relatively uniformly on the wafer substrate. Comparing the above two methods, the advantage of the flexible air cavity pressurization method is that the pressure in the wafer substrate area is adjustable and the local area can be modified, but it has a small 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 ability.

[0003] Based on the above-mentioned chemical mechanical polishing and planarization, for conductive substrates or film conductive materials, the conductive characteristics of the wafer substrate or the thin film on the wafer surface can be further utilized. Through an electrochemical mechanical polishing and planarization system, an electrochemical reaction is carried out on the surface of the wafer substrate or the thin film. Through the precise control of the circuit system, the surface chemical reaction rate is increased, and then the mechanical polishing and planarization efficiency is improved. In common embodiments, the polishing head is mainly of an insulating type. This insulating polishing head does not participate in the circuit architecture, and in some embodiments, a hard-contact vacuum conductive chuck head is applied. The circuit architecture of 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 scratching during the process. Additionally, in one of the current electrochemical mechanical planarization equipment, one of the current paths, the electrode is realized through the edge position of the polishing platform. Therefore, there is uneven current magnitude and distribution from the center to the edge on the polishing platform. Secondly, the vacuum conductive chuck head adsorbs and fixes the wafer. Through the movement of the mobile polishing platform, the relative movement stroke between the wafer and the polishing pad is small, which will cause unevenness in the electrochemical reaction on the wafer. In addition, such a conductive chuck head is often a hard disk loaded by the main shaft, and the rigid conductive disk does not have in-plane pressure adjustment control, so it cannot act on the wafer surface for in-plane uniformity control. In addition, there is also an electro-polishing head that loads the electrode around the outer circumference of the wafer. The wafer polishing surface is electrically conducted through multi-point contact. However, this electrode design is complex and there is contact wear with the outer circumference of the wafer. The above-mentioned two types of flexible cavity pressurized polishing heads and hard disk polishing heads (the wafer substrate is attached to the lower surface of the hard disk through wax sealing / film sticking) are used in the conventional chemical mechanical polishing and planarization. In the above two methods, both the flexible rubber airbag and the hard disk wax sealing / film sticking treatment are electrically insulating or weakly conductive, and cannot realize the export of amperage-level current on the wafer through the polishing head. Therefore, the main difficulties restricting the application of conductive polishing heads are 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, the conventional chemical mechanical polishing and planarization polishing head cannot take into account the optimization of the overall thickness change and the modifiable functionality of the local area. The technical routes of the above two polishing heads can be combined to develop a new type of polishing head that realizes overall thickness adjustment based on a hard disk and adds flexible cavity control to realize local adjustment. In addition, for the electrochemical polishing and planarization technology, the hard disk of the above polishing head is conductively treated to realize the application of the new type of polishing head in the electrochemical polishing and planarization technology. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a chemical mechanical polishing and planarization system. The hard disk can achieve the loading and unloading of the wafer substrate through pressure control in the third cavity, and can also adsorb or not adsorb the wafer substrate. The cooperation of the elastic unit and the second air cavity is used to control the movement of the hard disk with the wafer substrate, while 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 present invention to solve its technical problems is: a chemical mechanical polishing and planarization system, at least including a polishing head, and the polishing head includes:

[0007] A polishing head body;

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

[0009] An elastic unit, at least part of which is in a ring structure, is respectively connected to the polishing head body and the hard disk, and the polishing head body, the elastic unit and the hard disk enclose to form a second air cavity;

[0010] A retaining ring, located below the polishing head body, is an annular component that can contact the polishing pad, and 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 perform a flexible movement, assisting the hard disk and the wafer substrate to float, so as to achieve chemical mechanical polishing of the wafer substrate.

[0012] Further, the hard disk is made of a conductive material or its surface is conductively treated to achieve electrochemical mechanical polishing and planarization of the wafer substrate.

[0013] Further, in the 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 part of the lower surface of the hard disk; or the horizontal part of the lower surface of the hard disk forms a thickened area or a thinned area to form a height difference from nanometers to micrometers.

[0015] Further, the elastic unit is made of an elastic material, one side of its ring 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 air holes is 0.1 - 3 mm, and the total area thereof 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, a limiting edge member is provided on the hard disk, which can be abutted against the cut edge of the wafer substrate and the inner wall of the retaining ring respectively, or it can be abutted against the cut edge of the wafer substrate.

[0032] Furthermore, the retaining ring is provided with grooves for the polishing liquid to enter and exit, and the limiting edge member is provided with guiding grooves that can communicate with the grooves; the limiting edge member is made of an insulating material.

[0033] The beneficial effects of the present invention are as follows: 1) The use of the hard disk can achieve relatively uniform overall downward pressure, which helps to improve the overall thickness variation; 2) The use of elastic units for local pressurization can help to modify local areas of the hard disk; 3) When the flexible film drives the wafer substrate for polishing, when encountering areas such as grooves on the polishing pad, the force balance state fluctuates, which will affect the polishing speed and the polishing efficiency will be adversely affected. However, the hard drive in the hard disk has higher stability and can effectively avoid the above problems, and the process stability is better; 4) The hard drive in the hard disk solves the problem that when the flexible film drives the wafer substrate for polishing, under harsh polishing conditions, the flexible film is pulled and causes rupture or change in elastic modulus, and extends the service life of the flexible member in the polishing head; 5) The use of the hard disk to adsorb the wafer substrate by negative pressure, during the process of the polishing head leaving the polishing pad, it will not cause scratching between the wafer substrate and the polishing pad due to the return of the flexible film, ensuring that the wafer substrate can quickly and effectively disengage from the polishing pad and guaranteeing the orderly progress of the polishing process; 6) It can be applied to ordinary chemical mechanical polishing, and by conducting electricity on the hard disk, the application of electrochemical polishing and planarization processes can be realized, with high adaptability; 7) The use of the conductive hard disk to achieve the electrical connection between the polishing head and the wafer substrate for electrochemical mechanical polishing and planarization can ensure the long-term stability of the electrochemical reaction, and the process stability of electrochemical mechanical polishing and planarization is higher; 8) The limiting edge configured for a wafer substrate with a specific shape can effectively prevent the oxidation of the edge of the hard disk or the conductive flexible film thereon, thereby increasing the service life of the above components; 9) The use of the hard disk in cooperation with the flexible cavity to perform overall pressurization and local pressurization on the wafer substrate can optimize the overall thickness variation of the wafer substrate while achieving the modification of local areas. Description of the Drawings

[0034] Figure 1 It is the front view of the first embodiment of the present invention.

[0035] Figure 2 It is the three-dimensional structure schematic diagram of the first embodiment of the present invention Figure 1 .

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

[0037] Figure 4 It is a bottom view of the first embodiment of the present invention.

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

[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 present invention.

[0041] Figure 8 It is a schematic diagram of the cross-section structure of the hard disk in the first embodiment of the present invention.

[0042] Figure 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 present invention.

[0043] Figure 10 It is a cross-sectional view of the third embodiment of the present invention.

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

[0045] Figure 12 It is a schematic diagram of a partial three-dimensional structure of the third embodiment of the present invention.

[0046] Figure 13 A cross-sectional view of the fourth embodiment of the present invention Figure 1 .

[0047] Figure 14 A cross-sectional view of the fourth embodiment of the present invention Figure 2 .

[0048] Figure 15 It is a cross-sectional view of the fifth embodiment of the present invention.

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

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

[0051] Figure 18 It is a cross-sectional view of embodiment 6 of the present invention.

[0052] Figure 19Schematic diagram of the mating structure of the hard disk, the wafer substrate, and the edge limiting member in the seventh embodiment of the present invention Figure 1 。

[0053] Figure 20 Schematic diagram of the mating structure of the hard disk, the wafer substrate, and the edge limiting member in the seventh embodiment of the present invention Figure 2 。

[0054] Figure 21 Schematic diagram of the mating structure of the hard disk, the wafer substrate, and the edge limiting member in the seventh embodiment of the present invention Figure 3 。

[0055] Figure 22 Schematic diagram of the mating structure of the hard disk, the wafer substrate, and the edge limiting member in the seventh embodiment of the present invention Figure 4 。

[0056] Figure 23 Bottom view of the conductive cloth in the eighth embodiment of the present invention.

[0057] Wherein, 1 - polishing head body, 11 - guiding cylinder, 12 - radial moving gap, 13 - first air cavity, 2 - hard disk, 21 - air hole, 22 - third air cavity, 221 - conduit, 23 - guiding sleeve, 24 - guiding rod, 26 - fourth air cavity, 27 - air passage, 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 limiting member, 71 - guiding groove, 8 - wafer substrate, 81 - trimmed edge of the wafer substrate. Detailed implementation manners

[0058] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0059] Embodiment 1

[0060] As Figures 1 - 7 shown, a chemical mechanical polishing and planarization system includes at least a polishing head, which includes a polishing head body 1, a hard disk 2, an elastic unit 3 respectively connected to the polishing head body 1 and the hard disk 2, 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 movement and the lifting stroke of the polishing head body 1 part, and thus drive the hard disk 2 and the wafer substrate to move up and down.

[0061] The hard disk 2 means that the conductive disk is made of a hard material, such as metal, conductive material, or other conductive materials with rigidity. The metal can specifically be 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 a conductive material, so that the hard disk 2 can form a conduction circuit required for electrochemical mechanical polishing and planarization with the wafer substrate, polishing table, and power supply. After the power is conducted to the hard disk 2, it is then conducted to the wafer substrate for surface modification, and then mechanical polishing is carried out.

[0062] In the electrochemical mechanical polishing and planarization of the wafer substrate, 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 is connected from the polishing head body 1 to the hard disk 2, and there is no specific limitation.

[0063] At least part of the lower surface of the hard disk 2 is located in the same plane. In this embodiment, the lower surface of the hard disk 2 is all horizontal. Of course, in other embodiments, the horizontal part of the hard disk 2 can also be thickened or thinned in specific areas according to the thickness and topography of the wafer substrate, that is, a thickened area or a thinned area is formed to form a height difference from nanometers to micrometers between different areas. In other embodiments, the side surface of the hard disk 2 can be insulated and chamfered, and the insulation treatment includes but is not limited to hard oxidation, surface plating, and other methods.

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

[0065] The upper surface of the hard disk 2 is airtight. At least part of the lower surface of the hard disk 2 is horizontal, and a plurality of air holes 21 are opened in the horizontal part of the lower surface. A third air cavity 22 communicating with the air holes 21 is opened 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 polluting the polishing head. The rest can be realized 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. It can be realized by existing technologies and will not be elaborated here. The diameter of the air holes 21 is 0.1 - 3 mm, 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, specifically the horizontal part of the lower surface, can directly contact and adsorb the wafer substrate.

[0066] In this embodiment, all the air holes 21 are connected to each other, as Figure 8 shown, a gas path channel 27 that is radially staggered and connected is formed inside the hard disk 2. The gas path channel 27 communicates with the third air cavity 22, and the air holes 21 are correspondingly arranged in the area where the gas path channel 27 is located. Therefore, 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 chamber 22 to detect the vacuum condition of the third air chamber 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 is made of an elastic material and is generally in a ring structure. One side of it 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 enclose to form the second air chamber 4. The pressure in the second air chamber 4 is controllable. Thus, by adjusting the pressure in the second air chamber 4, the elastic unit 3 can be driven to perform a flexible movement to assist the hard disk 2 and the wafer substrate to float, realizing the electrochemical mechanical polishing and planarization of the wafer substrate. Here, the floating of the hard disk 2 and the wafer substrate means that on the premise of the mechanical drive of the polishing head body 1 and the hard disk 2, the elastic unit 3 is used to improve the movement of the hard disk 2 and the wafer substrate, and this movement includes up and down floating and radial floating. The control method of the pressure in the second air chamber 4 can be achieved by existing technologies and will not be elaborated here.

[0070] Regarding the sealing formation and pressure controllability of the second air chamber 4, it can be achieved by existing technologies and will not be elaborated here.

[0071] In the present invention, the traditional structure of using a hard support disk and a flexible film to adsorb the wafer substrate is changed. The hard disk 2 directly adsorbs the wafer substrate. On the basis of the existing drive structure, the elastic unit 3 assists the hard disk 2 and the wafer substrate to rotate, lift, swing, etc. within the retaining ring 5 under the change of the air pressure in the second air chamber 4, that is, the hard disk 2 and the wafer substrate perform up and down and radial floating, realizing the electrochemical mechanical polishing and planarization of the wafer substrate. The hard disk 2 can exhibit good electrical conductivity and thermal conductivity, and during the electrochemical mechanical polishing and planarization process, the polishing liquid and heat increase involved in the process will not have an adverse impact on the hard disk 2, nor will it be like the flexible film in the traditional structure with poor electrical conductivity, easy corrosion, and poor stability.

[0072] Embodiment Two

[0073] In Embodiment One, the movement of the hard disk 2 and the wafer substrate is realized by the existing mechanical drive structure, and at the same time, 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.

[0074] Such as Figure 9As shown, in this embodiment, a guide cylinder 11 extends from the central axis of the polishing head body 1 in the direction of the hard disk 2. A guide sleeve 23 is formed on the side of the hard disk 2 facing away from the wafer substrate. The guide sleeve 23 is concentric and coaxial with the hard disk 2. The guide cylinder 11 vertically extends into the guide sleeve 23, and there is a radial movement gap 12 between the two. Here, the radial movement gap 12 means that the outer diameter of the guide cylinder 11 is smaller than the inner diameter of the guide sleeve 23. Thus, after the guide cylinder 11 is inserted into the guide sleeve 23, while the elastic unit 3 drives the hard disk 2 to perform a flexible movement, the movement of the guide cylinder 11 can drive the guide sleeve 23, that is, a mechanical limit fit can also be achieved between the polishing head body 1 and the hard disk 2, making the movement controllability of the hard disk 2 higher.

[0075] Of course, in other embodiments, it can be that the guide sleeve 23 vertically extends into the guide cylinder 11, and there is a radial movement gap 12 between the two.

[0076] Embodiment Three

[0077] As Figures 10 - 12 shown, the polishing head body 1 includes a fourth air chamber 26, which is located above the hard disk 2, and the air pressure in the fourth air chamber 26 is variable, so as to pressurize or decompress the hard disk 2.

[0078] Specifically, the fourth air chamber 26 can be located above the central area of the hard disk 2, and at this time it is a hemispherical cavity; or, the fourth air chamber 26 is an annular or disc-shaped air chamber located above the hard disk 2 and concentric with it.

[0079] In this embodiment, the fourth air chamber 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 this downward pressure can be adjusted flexibly.

[0080] The pressure control of the fourth air chamber 26 can be achieved by existing technologies and will not be elaborated here.

[0081] Of course, multiple fourth air chambers can also be set to achieve directional pressurization or decompression of the hard disk 2, and further 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 that through multi-chamber pressurization, the stability of the polishing head can be further improved.

[0082] Embodiment Four

[0083] Based on Embodiment Two, at least one driving pin 61 is provided on one of the guide cylinder 11 and the guide sleeve 23, and a driving groove 62 is provided on the other. The driving pin 61 horizontally extends into the driving groove 62, and there is a circumferential movement gap between the two.

[0084] Specifically, as Figures 13 - 14As shown, drive pins 61 are formed on the outer periphery of the guide cylinder 11. In this embodiment, the number of drive pins 61 is multiple, and they 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 ones, without specific limitations.

[0085] Drive grooves 62 are formed on the guide sleeve 23, and the number of drive grooves 62 is the same as that of the drive pins 61, and they are also evenly spaced along the circumferential direction of the guide sleeve 23.

[0086] When the polishing head body 1 and the hard disk 2 are assembled, the drive pins 61 are inserted into the drive grooves 62, and the width of the drive pins 61 is smaller than the width of the drive grooves 62, so there is a circumferential movement gap between the two, that is, the drive pins 61 can swing circumferentially in the drive grooves 62. Thus, while the elastic unit 3 drives the hard disk 2 to perform a flexible movement and a mechanical limit fit is achieved between the polishing head body 1 and the hard disk 2, the mechanical drive of the polishing head body 1 to the hard disk 2 can also be realized through the drive pins 61 and the drive grooves 62, making the activities of the hard disk 2 driving the wafer substrate for electrochemical mechanical polishing and planarization more effective.

[0087] By using the drive pins 61 and the drive grooves 62 to achieve hard drive and the elastic unit 3 to assist the hard disk 2 to overcome slight disturbances, the controllability of the activities of the hard disk 2 and the wafer substrate is higher, the process stability is higher, and further the controllability of the electrochemical mechanical polishing and planarization or chemical mechanical polishing process is high.

[0088] Embodiment Five

[0089] In this embodiment, the hard disk 2 is provided with a guide rod 24, and the guide rod 24 vertically penetrates upward from the center of the polishing head body 1, and there is a radial movement gap between the guide rod 24 and the polishing head body 1.

[0090] On one side of the center axis of the polishing head body 1 facing the hard disk 2, a guide cylinder 11 is formed. At least one of the guide cylinder 11 and the guide rod 24 is provided with at least one drive pin 61, and the other is provided with a drive groove 62. The drive pin 61 extends into the drive groove 62, and there is a circumferential movement gap between the two.

[0091] Specifically, as Figures 15 - 17 shown, three drive pins 61 are evenly spaced along the circumferential direction on the outer wall of the guide rod 24, and three drive grooves 62 are formed by hollowing out the inner ring of the guide cylinder 11. The width of the drive grooves 62 is greater than the width of the drive pins 61, so when the drive pins 61 are inserted into the drive grooves 62, there is a circumferential movement gap between the two, that is, the drive pins 61 can swing circumferentially in the drive grooves 62.

[0092] Thus, while the elastic unit 3 drives the hard disk 2 to perform a flexible movement and a mechanical limit fit is achieved between the polishing head body 1 and the hard disk 2, the mechanical drive of the hard disk 2 by the polishing head body 1 can also be realized through the driving pin 61 and the driving groove 62, making the activity of driving the wafer substrate by the hard disk 2 for electrochemical mechanical polishing and planarization more effective.

[0093] Meanwhile, the inside of the guide rod 24 can be a hollow structure, and a conduit 221 is disposed therein. The conduit 221 is communicated with the third air chamber 22. Since the negative pressure of the third air chamber 22 sucks the polishing liquid into the conduit 221 when adsorbing the wafer substrate, the conduit 221 of the third air chamber 22 is flushed at the end of each polishing, and at the same time, the back surface of the wafer substrate is also flushed. The conduit 221 is connected to the gas path control system through the conductive slip ring of the polishing head body 1, and water-gas separation is performed.

[0094] Embodiment Six

[0095] In the above Embodiments One to Five, the gas input form of the second air chamber 4 is not limited, nor is it limited whether there are multiple sub-air chambers separated in the second air chamber 4.

[0096] As Figure 18 shown, different from the fact that the gas input channel 41 of the second air chamber 4 in Embodiment Five is one, in this embodiment, the second air chamber 4 has two gas input channels 41, which are symmetrically distributed along the radial direction. Therefore, the gas input of the second air chamber 4 is more uniform, the controllability is higher, and the drive of the hard disk 2 is more flexible and effective.

[0097] Embodiment Seven

[0098] For some conductive wafer substrates 8 with irregular shapes, such as the 6-inch silicon carbide wafer substrate 8 having a trimmed edge 81. Since there is no conductive wafer substrate 8 medium at the trimmed edge 81 position, after the hard disk 2 adsorbs the wafer substrate 8, some of its regions are still exposed to the outside, and the hard disk 2 will be directly energized and oxidized, affecting the life of the hard disk 2; in addition, due to the rotation, swing, and rotation of the polishing disc of the wafer substrate 8 with the polishing head body 1, there will also be relative sliding between the trimmed edge 81 of the wafer substrate 8 and the hard disk 2, resulting in electro-oxidation of the edge circle. Therefore, a limit design needs to be carried out for the special-shaped conductive wafer substrate 8 to limit the rotation of the wafer substrate 8 inside the polishing head body 1.

[0099] As Figure 19 shown, by adding a limiting member 7 on the surface of the hard disk 2, the material of the limiting member 7 is an insulating material, and it can be attached to or embedded in the hard disk 2, that is, the limiting member 7 can be abutted against the trimmed edge 81 of the wafer substrate and the inner wall of the retaining ring 5 respectively. The overall height of the limiting member 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 ≤ 0.3 mm.

[0100] To prevent the edge limiting member 7 from colliding with the edge vertices of the trimmed edge 81, the overall length of the edge limiting member 7 can be shortened, and the edges can be chamfered, as Figure 20 shown.

[0101] To allow the polishing liquid to better enter the polishing head body 1 through the groove 51 of the retaining ring 5, the edge limiting member 7 can also be provided with a guiding groove 71. The angle of the guiding groove 71 is on the extension line of the groove 51 of the retaining ring 5, and the width of the guiding groove 71 is the same as the width of the groove 51 of the retaining ring 5, as Figure 21 shown.

[0102] As Figure 22 shown, the above-mentioned edge limiting member 7 can also be simplified to a multi-point limiting structure with the number of points N≥2. At this time, the edge limiting member 7 abuts against the trimmed edge 81 of the wafer substrate.

[0103] Example Eight

[0104] In this embodiment, a flexible conductive cloth 28 is attached to the lower surface of the hard disk 2, and its resistivity is <10 -3 mΩ·cm. As Figure 23 shown, the flexible conductive cloth 28 includes air holes 281, and the positions of at least part of the air holes 281 match the positions of the air holes 21 of the hard disk 2. When the air chamber 3 is pressurized or evacuated, the air path is smoother, which is beneficial for better adsorption of the wafer when the air chamber 3 is evacuated.

[0105] Of course, the above-mentioned flexible conductive cloth 28 can also be just a flexible cloth without the need to achieve the conductive function. That is, the flexible cloth is a non-conductive material. At this time, the air holes of the flexible cloth are filled with an 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 an electrolyte to connect the back surface of the wafer substrate and the wafer bearing surface of the polishing head body 1 to form a circuit.

[0106] Specifically, some of the air holes can be filled with an electrolyte, and some of the air holes are only used for adsorbing the wafer substrate; it is also possible that a single air hole simultaneously functions to adsorb the wafer substrate and conduct the energized circuit, that is, the electrolyte flows through the inner wall of the air hole to achieve the function of connecting the back surface of the wafer substrate and the wafer bearing surface of the polishing head body 1 to form a circuit.

[0107] Of course, the flexible cloth can be not only a woven cloth, but also a foamed polymer, or can be a sponge structure with upper and lower connections. As long as the flexible cloth is non-conductive and has a certain flexibility, it can be ensured that the back surface of the wafer substrate will not be worn, and specific restrictions are not made.

[0108] The other structures are the same as any of the embodiments from Embodiment One to Embodiment Five, and will not be described in detail.

[0109] Example Nine

[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 the passage of gas under the conditions of air extraction and pressurization, and does not support the adsorption and passage of moisture, so as to ensure that no chemical substances and moisture are inhaled during the negative pressure operation of the wafer substrate. The waterproof and breathable layer can be attached to the entire surface, or only to the position of the lower surface air holes 21 of the hard disk 2. When attached to the entire surface, the waterproof and breathable layer needs to have conductivity. When attached to the position of the air holes 21, conductive adhesive bonding is required at the edges of both sides of the waterproof and breathable layer.

[0111] Other structures are the same as any of the embodiments from Embodiment 1 to Embodiment 5, and will not be described in detail.

[0112] The above specific embodiments are used to explain and illustrate the present invention, rather than to limit the present invention. Any modifications and changes made within the spirit and scope of the claims of the present invention 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, 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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