Polishing pressure head, polishing equipment and method for polishing square substrate

Abstract

The invention discloses a polishing pressure head, polishing equipment and a polishing method for polishing a square substrate. The polishing pressure head comprises a connecting plate and a plurality of piezoelectric assemblies, wherein the piezoelectric assemblies are arranged on the connecting plate and located between the connecting plate and a square substrate to be polished, each piezoelectric assembly is provided with a pressure transmission face used for transmitting pressure to the square substrate, and the pressure transmission faces of the different piezoelectric assemblies are used for transmitting pressure to different polishing areas of the square substrate. And in the polishing process, according to the speeds of different polishing areas of the square substrate, the input voltage of the piezoelectric assembly is adjusted to control the pressure transmitted to the corresponding polishing area of the square substrate by the pressure transmission surface. According to the polishing device, the technical effects that the consistent or approximate material removal rate can be kept in the polishing areas with different speeds on the square substrate, and the material removal uniformity and the surface flatness of the square substrate are improved are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of polishing equipment, and more particularly, to a polishing head for polishing a square substrate, a polishing equipment, and a polishing pressure control method. Background Art

[0002] As a chip advanced packaging technology, TGV (Through Glass Via) has been extensively researched and developed in various countries around the world. Its core material is a glass substrate, and the polishing of the glass substrate is involved in the production process. With the increasing size of the package, there are higher and thinner requirements for the size of the glass substrate.

[0003] However, the polishing of ultra-large and ultra-thin glass substrates (for example, glass substrates with a size specification of more than 500 mm in length, more than 500 mm in width, and a thickness between 0.5 mm and 1 mm) is still under research and development in laboratories. Due to the extremely large size, the polishing speed difference between the edge area and the central area of the glass substrate is extremely large. Due to the ultra-thin thickness, there are extremely high requirements for the surface flatness of the glass substrate, usually at the micron level.

[0004] In the prior art, the polishing accuracy of ultra-large and ultra-thin glass substrates fails to meet the requirements of mass production. Summary of the Invention

[0005] The main objective of the present invention is to provide a polishing head, a polishing equipment, and a polishing pressure control method to solve the problems in the related art that during the polishing of ultra-large and ultra-thin square substrates, it is difficult to control the pressure, the surface material removal rate is uneven, and the surface flatness is low.

[0006] To achieve the above objective, the present invention provides a polishing head, including: a connecting plate and a plurality of piezoelectric components; wherein, The plurality of piezoelectric components are disposed on the connecting plate and located between the connecting plate and the square substrate to be polished. The piezoelectric component has a pressure transmission surface for transmitting pressure to the square substrate. The pressure transmission surfaces of different piezoelectric components are used to transmit pressure to different polishing areas of the square substrate, so as to adjust the input voltage of the piezoelectric component according to the speed of different polishing areas of the square substrate during the polishing process to control the pressure transmitted from the pressure transmission surface to the corresponding polishing area of the square substrate.

[0007] Optionally, the plurality of piezoelectric components are arranged in a matrix manner to match the shape of the square substrate.

[0008] Optionally, the plurality of piezoelectric components uniformly cover the square substrate to match the shape of the square substrate.

[0009] Optionally, during the polishing process, according to the speed of different polishing areas of the square substrate, the input voltage of the piezoelectric component is adjusted to control the pressure transmitted by the pressure transmission surface to the corresponding polishing area of the square substrate. Specifically: The square substrate is divided into multiple polishing areas, and each polishing area corresponds to at least one of the piezoelectric components, and the speed of each polishing area during the polishing process is determined; According to the speed of the polishing area, the input voltage of the piezoelectric component is controlled to change the pressure transmitted by the piezoelectric component to the polishing area, so that the square substrate reaches the target material removal rate.

[0010] Optionally, according to the speed of the polishing area, the input voltage of the piezoelectric component is controlled to change the pressure transmitted by the piezoelectric component to the polishing area. Specifically: Through the following corresponding relationship, the square substrate reaches the target material removal rate: , Wherein, is the material removal rate of the corresponding polishing area of the square substrate to the piezoelectric component, is the Preston constant, is the speed of the corresponding polishing area of the square substrate to the piezoelectric component, is the surface area of the piezoelectric material in the piezoelectric component, is the elastic modulus of the piezoelectric material when the electric field is zero or constant, is the input voltage of the piezoelectric component, is the piezoelectric constant, is the thickness of the piezoelectric material, is the surface area of the pressure transmission surface on the piezoelectric component.

[0011] Optionally, the piezoelectric component includes a piezoelectric layer and a first pressing plate. The piezoelectric layer is located between the connecting plate and the first pressing plate, so that the first pressing plate applies a pre-tightening force to the piezoelectric layer, and the piezoelectric layer transmits pressure to the square substrate through the first pressing plate.

[0012] Optionally, the piezoelectric component further includes a connecting column. The first end of the connecting column is fixedly connected to the first pressing plate, and the second end of the connecting column passes through the piezoelectric layer and is fixedly connected to the connecting plate. By adjusting the axial fixed position of the connecting column on the connecting plate, the magnitude of the pre-tightening force applied by the first pressing plate to the piezoelectric layer is changed.

[0013] Optionally, the stiffness of the first pressing plate is greater than that of the connecting column. During the pressure transmission process, the connecting column generates axial elastic deformation under the pressure of the piezoelectric layer to provide the displacement required for the first pressing plate to transmit pressure.

[0014] Optionally, the connecting column is a hollow columnar structure, and a wire routing hole is provided on the connecting column. The cable connected to the piezoelectric layer enters the connecting column through the wire routing hole and extends out of the second end of the connecting column into the wire routing space above the connecting plate.

[0015] Optionally, the piezoelectric assembly further includes a second pressing plate, which is disposed between the connecting plate and the piezoelectric layer. The second end of the connecting column passes through the second pressing plate and is fixedly connected to the connecting plate.

[0016] Optionally, a buffer pad is further included, which is disposed between the pressure transmission surface of the piezoelectric assembly and the square substrate. The pressure on the pressure transmission surface is transmitted to the square substrate through the buffer pad.

[0017] Optionally, a retaining ring is further included, which is disposed on one side of the connecting plate. The retaining ring is used to confine the square substrate within the retaining ring.

[0018] Optionally, the buffer pad covers the pressure transmission surfaces of multiple piezoelectric assemblies, wraps around the piezoelectric assemblies, and seals between the ring side of the piezoelectric assemblies and the retaining ring.

[0019] Optionally, the polishing head further includes a driving member, which is used to drive the retaining ring to move towards and away from the polishing pad.

[0020] Optionally, the driving member includes an airbag assembly, which is connected to the retaining ring, and drives the retaining ring to move through the expansion and contraction of the airbag assembly.

[0021] Optionally, multiple airbag assemblies are provided, and the multiple airbag assemblies are arranged around the retaining ring.

[0022] Optionally, the airbag assembly includes an airbag, a first connecting member, and a second connecting member; The first connecting member and the second connecting member are respectively fixed to the first end and the second end of the airbag, and the second connecting member is connected to the retaining ring.

[0023] Optionally, the polishing head further includes: A support disk, which is used to connect to the machine table. A wire routing channel is provided inside the support disk, and the first connecting member is connected to the support disk; The connecting plate is fixed on the side of the support disk facing the square substrate. There is a wire routing space between the connecting plate and the support disk, and the wire routing channel is communicated with the wire routing space for the cable of the piezoelectric assembly to pass through.

[0024] Optionally, a plurality of fixing posts are provided on one side of the connecting plate facing the supporting disk, and the end portions of the fixing posts are fixedly connected to the supporting disk, so that a wiring space is formed between the connecting plate and the supporting disk.

[0025] Optionally, a first connection groove is provided on the supporting disk, a second connection groove is provided on the retaining ring, the first connecting member is fixedly fitted with the first connection groove, and the second connecting member is fixedly fitted with the second connection groove.

[0026] Optionally, an insertion port is provided on the side surface of the supporting disk and the side surface of the retaining ring, the insertion port communicates with the corresponding first connection groove and the second connection groove, the first connecting member is inserted into the first connection groove through the corresponding insertion port, and the second connecting member is inserted into the second connection groove through the corresponding insertion port.

[0027] Optionally, a first air passage is provided on the first connecting member, a second air passage is provided on the supporting disk, the first air passage communicates with the airbag, and the second air passage is used for communicating with a pressure control source.

[0028] Optionally, a guiding structure is further included. The first end of the guiding structure is connected to the supporting disk, the second end of the guiding structure is connected to the retaining ring, and the guiding structure provides guidance for the movement of the retaining ring.

[0029] Optionally, the guiding structure includes a guiding shaft. A third connecting member is provided at the second end of the guiding shaft, the third connecting member is fixedly fitted with the second connection groove, and a guiding hole is provided on the supporting disk. The upper end of the guiding shaft is slidably connected to the guiding hole.

[0030] According to another aspect of the present invention, a polishing device is provided, including the above-mentioned polishing head.

[0031] According to another aspect of the present invention, a polishing method is provided, using the above-mentioned polishing head. The method includes: Dividing the square substrate into a plurality of polishing areas, and each polishing area corresponds to at least one of the piezoelectric components; Determining the speed of each polishing area during the polishing process; According to the speed of the polishing area, controlling the input voltage of the piezoelectric component, and changing the pressure transmitted from the piezoelectric component to the polishing area, so that the square substrate reaches the target material removal rate. In an embodiment of the present invention, a connecting plate and a plurality of piezoelectric components are provided; wherein, the plurality of piezoelectric components are arranged on the connecting plate and located between the connecting plate and the square substrate to be polished. The piezoelectric components have a pressure transmission surface for transmitting pressure to the square substrate, and the pressure transmission surfaces of different piezoelectric components are used to transmit pressure to different polishing areas of the square substrate, so as to adjust the input voltage of the piezoelectric components according to the speed of different polishing areas of the square substrate during the polishing process to control the pressure transmitted from the pressure transmission surface to the corresponding polishing area of the square substrate.

[0032] On the one hand, after arranging a plurality of piezoelectric components on the connecting plate, the input voltage of each piezoelectric component can be controlled to control the pressure transmitted by the pressure transmission surface of each piezoelectric component. Since different piezoelectric components correspond to different polishing areas of the square substrate, the pressure borne by different polishing areas on the square substrate can be controlled, thus achieving the technical effect of enabling the polishing areas with different speeds on the square substrate to also maintain a consistent material removal rate, and improving the material removal uniformity and surface flatness of the square substrate. Especially when it comes to a large-sized ultra-thin square substrate, some of the plurality of independent piezoelectric components can be relatively easily arranged to directly correspond to the corner areas and the central areas of the sides of the square substrate. By controlling the input voltage of the piezoelectric components at this position, the pressure on the corresponding polishing areas of the square substrate can be controlled, thereby controlling the material removal uniformity of the corresponding polishing areas, and enabling the corner areas and the central areas of the sides of the square substrate to relatively simply achieve the effect of local pressure control, and further improving the overall material removal uniformity and surface flatness of the square substrate. On the other hand, after arranging a plurality of independent piezoelectric components, since local pressure control can be performed on different polishing areas of the square substrate, when polishing a large-sized square substrate, the deformation caused by its own weight at the edge of the large-sized polishing head can be compensated to adjust the additional pressure applied to the square substrate due to the deformation of the edge of the polishing head during the polishing process, further improving the material removal uniformity and surface flatness of the square substrate. On yet another hand, after using piezoelectric components as the pressure transmission members for the square substrate, controlling the pressure only requires changing the input voltage, and correspondingly only cables connected to the piezoelectric components need to be arranged on the polishing head. Compared with the need to separately arrange gas path channels or liquid path channels for each chamber, the overall structure is simpler, and at the same time, the sealing performance requirements for the polishing head are also lower, resulting in lower production and manufacturing costs, and more accurate pressure control. Description of the Drawings

[0033] The accompanying drawings, which form a part of the present invention, are used to provide a further understanding of the present invention, making other features, objects, and advantages of the present invention more apparent. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 is a schematic cross-sectional structure diagram of a polishing head according to an embodiment of the present invention; Figure 2 is Figure 1 a partially enlarged structure diagram in Figure 3 is a schematic bottom view structure diagram of a polishing head according to an embodiment of the present invention; Figure 4 is a schematic axonometric structure diagram of a polishing head according to an embodiment of the present invention; Figure 5 is a schematic diagram of the partition of a square substrate according to an embodiment of the present invention; Figure 6 is a schematic diagram of the partition of a piezoelectric component according to an embodiment of the present invention; Figure 7 is a schematic structure diagram of a piezoelectric component according to an embodiment of the present invention; Figure 8 is a schematic structure diagram of a first pressing plate according to an embodiment of the present invention; Figure 9 is a schematic cross-sectional structure diagram of a first pressing plate according to an embodiment of the present invention; Figure 10 is a schematic structure diagram of an airbag assembly according to an embodiment of the present invention; Figure 11 is a schematic cross-sectional structure diagram of an airbag assembly according to an embodiment of the present invention; Figure 12 is a schematic structure diagram of a guiding structure according to an embodiment of the present invention; Figure 13 is a schematic structure diagram of a retaining ring according to an embodiment of the present invention; Figure 14 is a schematic structure diagram of a support disk according to an embodiment of the present invention; Figure 15 is a schematic bottom view structure diagram of a support disk according to an embodiment of the present invention; Figure 16 is a schematic structure diagram of a connecting plate according to an embodiment of the present invention; Figure 17 is a schematic structure diagram after a piezoelectric component is installed on a connecting plate according to an embodiment of the present invention; Figure 18 is a schematic structure diagram from another perspective after a piezoelectric component is installed on a connecting plate according to an embodiment of the present invention; Figure 19It is a schematic structural diagram of a buffer pad in an embodiment of the present invention; Among them, 1. Rigid member; 101. Support plate; 1010. Guide hole; 1011. Second air passage; 102. Connecting plate; 1020. Fixed column; 103. Airbag assembly; 1030. Airbag; 1031. First connecting member; 10310. First air passage; 1032. Second connecting member; 104. Retaining ring; 1040. Liquid flow groove; 2. Piezoelectric component; 20. Piezoelectric layer; 21. First pressing plate; 22. Second pressing plate; 23. Gasket; 24. Nut; 25. Connecting column; 250. Wiring hole; 200. Pressure transmission surface; 3. Buffer pad; 4. Square substrate; 5. Wiring space; 6. Wiring channel; 7. Guide structure; 70. Guide shaft; 71. Third connecting member; 8. First connection groove; 9. Second connection groove. Detailed implementation manners

[0034] 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 with reference to 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 creative efforts shall fall within the protection scope of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so as to describe the embodiments of the present invention here.

[0036] In the present invention, the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation.

[0037] Moreover, in addition to being able to represent an orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0038] In addition, terms such as "arranged", "provided with", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In addition, the meaning of the term "plurality" should be two or more.

[0040] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0041] To solve the related technical problems, such as Figures 1 to 6 As shown, an embodiment of the present invention provides a polishing head, including: a connecting plate 102 and a plurality of piezoelectric components 2; wherein, The plurality of piezoelectric components 2 are arranged on the connecting plate 102 and are located between the connecting plate 102 and the square substrate 4 to be polished. The piezoelectric component 2 has a pressure transmission surface 200 for transmitting pressure to the square substrate 4. The pressure transmission surfaces 200 of different piezoelectric components 2 are used to transmit pressure to different polishing areas of the square substrate 4. During the polishing process, according to the speeds of different polishing areas of the square substrate 4, the input voltage of the piezoelectric component 2 is adjusted to control the pressure transmitted by the pressure transmission surface 200 to the corresponding polishing area of the square substrate 4, so as to control the material removal rate of the corresponding polishing area of the square substrate 4.

[0042] In this embodiment, the connecting plate 102 includes a rigid structure and can move under the action of a machine tool device and transmit the pressure from the machine tool device. The piezoelectric component 2 is installed between the connecting plate 102 and the square substrate 4 to be polished, specifically on the side of the connecting plate 102 opposite to the square substrate 4. Taking the example of the polishing head transmitting pressure downward to the square substrate 4, as Figure 1 shown, the piezoelectric component 2 is installed at the lower end of the connecting plate 102, and the piezoelectric component 2 can transmit pressure to the square substrate 4 located below. To achieve local pressure control of different polishing areas of the square substrate 4, a plurality of piezoelectric components 2 are included in this embodiment. The plurality of piezoelectric components 2 are arranged on the connecting plate 102 in a certain arrangement manner, and the specific arrangement manner can be set according to the area division method of the square substrate 4.

[0043] In one implementation manner, the square substrate 4 can be divided into a plurality of polishing areas in a grid pattern, and the plurality of polishing areas are arranged in an array. For the square substrate 4, as Figure 5As shown, it can be divided into multiple complete rectangular polishing areas. Specifically, as shown in the figure, during the polishing process, the square substrate 4 rotates around the center point O at an angular velocity rotation. Assuming that in the square substrate 4, the distance from the center point O to the right-angle point is , then the rotational linear velocity of this polishing area is approximately . The distance from the center point O to the right-angle side is , then the rotational linear velocity of this polishing area is approximately . Obviously, in the square substrate 4, , . According to the Preston equation ( is the material removal rate, is the Preston constant, is the polishing pressure, is the instantaneous relative velocity of any point on the surface of the square substrate 4 relative to the polishing pad), under the condition of the same polishing pressure the material removal rate of the area is less than the material removal rate of the area.

[0044] In the actual processing process, it is impossible to infinitely divide the square substrate into grids. According to the division method shown in Figure 5 , for the polishing area the material removal rate , is the average pressure of the polishing area , is the average velocity of the polishing area . Similarly, the material removal rates of other polishing areas can be obtained , where , .

[0045] Based on this, the multiple piezoelectric components 2 on the polishing head adopt a matrix distribution as shown in Figure 6 . The multiple piezoelectric components 2 are evenly covered on the square substrate 4 in cooperation with the shape of the square substrate 4, so as to correspond to the polishing area division method on the square substrate 4. During the polishing process, according to the speeds of the respective polishing areas divided by the square substrate 4, the input voltage of the corresponding piezoelectric component 2 is adjusted to control the pressure transmitted by the pressure transmission surface 200 to the corresponding polishing area, so as to control the material removal rate of the corresponding polishing area on the square substrate 4, so that the material removal rates of the respective polishing areas on the surface of the square substrate 4 reach the same or nearly the same, and improve the uniformity and flatness of the surface material removal.

[0046] In this embodiment, the piezoelectric component 2 is a key component for transmitting pressure. The piezoelectric component 2 includes piezoelectric materials. According to the characteristics of piezoelectric materials, when a voltage is applied to them, the piezoelectric materials generate electric displacement, and the pressure is transmitted by using this electric displacement. Within the range of electric displacement, the greater the input voltage, the greater the electric displacement generated by the piezoelectric materials, and the greater the transmitted pressure, and vice versa. The piezoelectric materials included in the piezoelectric component 2 can be piezoelectric crystals, such as quartz crystals, etc., or piezoelectric ceramics, or semiconductor piezoelectric materials, etc., which are not limited in this embodiment.

[0047] On the one hand, in the present invention, after arranging a plurality of piezoelectric components 2 on the connecting plate 102, the input voltage of each piezoelectric component 2 can be controlled to control the pressure transmitted by the pressure transmission surface 200 of each piezoelectric component 2. Since different piezoelectric components 2 correspond to different polished areas of the square substrate 4, the pressure borne by different polished areas on the square substrate 4 can be controlled, so as to achieve the technical effect of enabling the polished areas with different speeds on the square substrate 4 to maintain a consistent material removal rate, and improving the material removal uniformity and surface flatness of the square substrate 4; Especially when it comes to a large-size and ultra-thin square substrate 4, some of the plurality of independent piezoelectric components 2 can be relatively easily arranged to directly correspond to the corner areas and the central areas of the sides of the square substrate 4. By controlling the input voltage of the piezoelectric components 2 at these positions, the pressure of the corresponding polished areas on the square substrate 4 can be controlled, so as to control the material removal uniformity of the corresponding polished areas, and the corner areas and the central areas of the sides of the square substrate 4 can also relatively simply achieve the effect of local pressure control, thereby improving the overall material removal uniformity and surface flatness of the square substrate 4; On the other hand, after arranging a plurality of independent piezoelectric components 2, since local pressure control can be performed on different polished areas of the square substrate 4, when polishing a large-size square substrate 4, the deformation caused by its own weight at the edge of the large-size polishing head can be compensated to adjust the additional pressure applied to the square substrate 4 due to the deformation of the edge of the polishing head during the polishing process, further improving the material removal uniformity and surface flatness of the square substrate 4; On yet another hand, after using the piezoelectric component 2 as the pressure transmission member for the square substrate 4, controlling the pressure only requires changing the input voltage, and correspondingly only requires arranging cables connected to the piezoelectric component 2 on the polishing head. Compared with the need to separately arrange gas path channels or liquid path channels for each chamber, the overall structure is simpler, and at the same time, the sealing performance requirements for the polishing head are also lower, resulting in lower production and manufacturing costs and more accurate pressure control.

[0048] Finally, in conventional film pressing, the film is a flexible structure. Since the square substrate 4 applies a force on the film in the rotation plane during rotation, it is easy to cause the film to be stretched outwards, resulting in uneven pressure transmission. However, in the present invention, the piezoelectric component 2 is a relatively rigid structure. After contacting the square substrate 4, the rotation of the square substrate 4 is not likely to cause deformation of the piezoelectric component 2, so that the pressure can be evenly transmitted to the square substrate 4.

[0049] In one embodiment, during the polishing process, according to the speeds of different polishing regions of the square substrate, the input voltage of the piezoelectric component is adjusted to control the pressure transmitted by the pressure transmission surface to the corresponding polishing region of the square substrate. Specifically: The square substrate is divided into multiple polishing regions, and each polishing region corresponds to at least one of the piezoelectric components, and the speed of each polishing region during the polishing process is determined; According to the speed of the polishing region, the input voltage of the piezoelectric component is controlled to change the pressure transmitted by the piezoelectric component to the polishing region, so that the square substrate reaches the target material removal rate.

[0050] Among them, according to the speed of the polishing region, the input voltage of the piezoelectric component is controlled to change the pressure transmitted by the piezoelectric component to the polishing region. Specifically: Through the following corresponding relationship, the square substrate reaches the target material removal rate: , Among them, is the material removal rate of the polishing region corresponding to the piezoelectric component 2 on the square substrate 4, is the Preston constant, is the speed of the polishing region corresponding to the piezoelectric component 2 on the square substrate 4, is the surface area of the piezoelectric material in the piezoelectric component 2, is the elastic modulus of the piezoelectric material when the electric field is zero or a constant, is the input voltage of the piezoelectric component 2, is the piezoelectric constant, is the thickness of the piezoelectric material, is the surface area of the pressure transmission surface 200 on the piezoelectric component 2.

[0051] In this embodiment, the material removal rate of the square substrate 4 and the rotation speed of the square substrate 4 are preset in advance. Based on the rotation speed of the square substrate 4 and according to the positions of the polishing areas divided on the square substrate 4, the speeds of the respective polishing areas can be calculated. The speed can be the average speed of the polishing area or the central speed. The surface area of the piezoelectric material, the elastic modulus of the piezoelectric material when the electric field is zero or constant, the thickness of the piezoelectric material, the surface area of the pressure transmission surface 200 on the piezoelectric component 2, and the piezoelectric constant are physically known quantities. Therefore, based on the above relationships, the input voltages of the respective piezoelectric components can be calculated. By controlling the input voltages of the respective piezoelectric components in this way, the square substrate 4 can achieve the target material removal rate.

[0052] During the polishing process, the input voltages of the respective piezoelectric components 2 can be controlled according to the above corresponding relationships, so that the material removal rates of the respective polishing areas on the square substrate 4 are kept consistent or close.

[0053] In one embodiment of the piezoelectric component 2, as Figure 7 shown, the piezoelectric component 2 includes a piezoelectric layer 20. The piezoelectric layer 20 is a piezoelectric material and can generate an electric displacement to transmit pressure after an input voltage is applied. To enable the piezoelectric layer 20 to better transmit pressure, a certain pre-tightening force needs to be applied to the piezoelectric layer 20. Therefore, in this embodiment, the piezoelectric component 2 further includes a first pressing plate 21. One side of the piezoelectric layer 20 away from the square substrate 4 is constrained on the connecting plate 102, and the other side is in contact with the first pressing plate 21. That is, the piezoelectric layer 20 is located between the connecting plate 102 and the first pressing plate 21. The constraint method of the piezoelectric layer 20 on the connecting plate 102 can be an adhesive constraint, that is, the piezoelectric layer 20 is adhesively fixed on the connecting plate 102, or the piezoelectric layer 20 is pre-installed in a specific rigid member and then the rigid member is fixed on the connecting plate 102. The piezoelectric layer 20 can still generate an electric displacement to transmit pressure after being constrained to the connecting plate 102.

[0054] After the first pressing plate 21 is in contact with the piezoelectric layer 20, the pressure of the piezoelectric layer 20 needs to be transmitted through the first pressing plate 21. The surface of the first pressing plate 21 close to the square substrate 4 serves as the pressure transmission surface 200 of the piezoelectric component 2. While serving as a pressure transmission member, the first pressing plate 21 also needs to apply a pre-tightening force to the piezoelectric layer 20. In one embodiment, the first pressing plate 21 presses the piezoelectric layer 20 through a connecting member connected to the connecting plate 102 to apply a pre-tightening force to the piezoelectric layer 20. At this time, to achieve pressure transmission, when the piezoelectric layer 20 generates an electric displacement, the first pressing plate 21 or the connecting member needs to deform to transmit the pressure. To enable the first pressing plate 21 to uniformly transmit pressure to the square substrate 4, it is preferably the connecting member that deforms to transmit the pressure.

[0055] According to the different structures of the connecting members, the ways of deforming to transmit while ensuring the pre-tightening force are different. In one embodiment, asFigures 7 to 9 As shown, the piezoelectric component 2 further includes a connecting column 25, and the connecting column 25 serves as a connecting member connecting the first pressing plate 21 and the connecting plate 102. Specifically, the first end of the connecting column 25 is fixedly connected to the first pressing plate 21, and the second end of the connecting column 25 passes through the piezoelectric layer 20 and is fixedly connected to the connecting plate 102. By adjusting the axial fixing position of the connecting column 25 on the connecting plate 102, the magnitude of the pre-tightening force applied by the first pressing plate 21 to the piezoelectric layer 20 is changed.

[0056] In this embodiment, the connecting column 25 has a columnar structure. The first end of the connecting column 25 (i.e., the lower end as shown in Figure 8 is fixedly connected to the first pressing plate 21, and the two can be fixedly connected by welding or integrally formed. The second end of the connecting column 25 (i.e., the upper end as shown in Figure 8 passes through a preset hole position on the piezoelectric layer 20 and is fixedly connected to the connecting plate 102. Through the connection between the connecting column 25 and the connecting plate 102, the first pressing plate 21 can apply an upward force to the piezoelectric layer 20, thereby pressing and constraining the piezoelectric layer 20 on the connecting plate 102 and applying a certain pre-tightening force to the piezoelectric layer 20. At the same time, the magnitude of the pre-tightening force applied by the first pressing plate 21 to the piezoelectric layer 20 can be changed by adjusting the axial fixing position of the connecting column 25 on the connecting plate 102.

[0057] In one embodiment, as shown in Figure 1 , Figure 2 and Figure 7 , the second end of the connecting column 25 penetrates into the connecting plate 102 and is sleeved with a gasket 23 and threadedly connected with a locking nut 24. By rotating the locking nut 24, the axial position of the connecting column 25 is adjusted, and further the magnitude of the pre-tightening force applied by the first pressing plate 21 to the piezoelectric layer 20 is changed.

[0058] In another embodiment, the connecting column 25 can be inserted into the connecting plate 102 and connected by snap connection. A plurality of snap positions are arranged axially on the connecting column 25, and the axial position of the connecting column 25 is adjusted by changing the snap position. For realizing linear pre-tightening force adjustment, the first embodiment is preferably adopted.

[0059] During the pressure transmission process, the pressure of the piezoelectric layer 20 first acts on the first pressing plate 21. Since the first pressing plate 21 is connected to the connecting plate 102 through the connecting column 25, this pressure will also be transmitted to the connecting column 25. To enable the first pressing plate 21 to uniformly transmit the pressure to the square substrate 4, under the pressure of the piezoelectric layer 20, the connecting column 25 needs to generate a tensile deformation, and the first pressing plate 21 uses the displacement provided by this deformation to transmit the pressure. For this reason, in this embodiment, the stiffness of the first pressing plate 21 is greater than that of the connecting column 25. During the pressure transmission process, the connecting column 25 generates an axial elastic deformation under the pressure of the piezoelectric layer 20 to provide the displacement required for the first pressing plate 21 to transmit the pressure. To achieve uniform force transmission, the connecting column 25 is connected to the center of the first pressing plate 21.

[0060] Since the piezoelectric assembly 2 needs to input voltage to control the output pressure, the piezoelectric assembly 2 needs to be connected to a power supply device through a cable. To achieve wire routing in a limited space, as Figure 8 and Figure 9 shown, in this embodiment, the connecting column 25 is a hollow columnar structure, and a wire routing hole 250 is provided on the connecting column 25. The cable connected to the piezoelectric layer 20 enters the channel 252 of the connecting column 25 through the wire routing hole 250 and extends out from the opening 251 at the second end of the connecting column 25 and enters the wire routing space 5 of the connecting plate 102.

[0061] Specifically, in this embodiment, the wire routing hole 250 is opened on the lower side surface of the connecting column 25. The piezoelectric layer 20 is sleeved on the connecting column 25 and is attached to the first pressing plate 21 at the lower end. The cable connected to the piezoelectric layer 20 passes through the wire routing hole 250 and penetrates into the hollow channel of the connecting column 25, and then extends upward through the upper end of the connecting column 25 and enters the wire routing space 5 of the connecting plate 102. The cables of the piezoelectric layers 20 in multiple piezoelectric assemblies 2 can pass through the corresponding connecting columns 25 and then converge in the wire routing space 5 in the connecting plate 102. After converging into a main cable, they are connected to an external power supply device.

[0062] In this embodiment, on the one hand, the channel in the hollow connecting column 25 is used for wire routing, saving the layout space of the cable. On the other hand, the hollow connecting column 25 is easier to make its stiffness lower than that of the first pressing plate 21, which is conducive to the first pressing plate 21 for pressure transmission.

[0063] On the basis of the above embodiment, to protect the piezoelectric layer 20, as Figure 7 shown, the piezoelectric assembly 2 in this embodiment further includes a second pressing plate 22. The second pressing plate 22 is attached to the side of the piezoelectric layer 20 away from the square substrate 4. The side of the second pressing plate 22 away from the piezoelectric layer 20 is attached to the connecting plate 102, that is, the second pressing plate 22 is arranged between the connecting plate 102 and the piezoelectric layer 20. The second end of the connecting column 25 passes through the second pressing plate 22 and is fixedly connected to the connecting plate 102.

[0064] Specifically, in this embodiment, the second pressing plate 22 and the first pressing plate 21 are respectively attached to the upper surface and the lower surface of the piezoelectric layer 20. The upper end of the connecting column 25 passes through the second pressing plate 22 and is fixedly connected to the connecting plate 102, so as to press and fix the first pressing plate 21, the piezoelectric layer 20 and the second pressing plate 22 on the connecting plate 102. The length dimensions of the first pressing plate 21, the piezoelectric layer 20 and the second pressing plate 22 can be kept consistent. In one implementation, the first pressing plate 21, the piezoelectric layer 20 and the second pressing plate 22 are all rectangular.

[0065] Since the first pressing plate 21 is a rigid structure, in order to avoid the first pressing plate 21 directly contacting the square substrate 4 and damaging the square substrate 4, the polishing head in this embodiment further includes a buffer pad 3. The buffer pad 3 is disposed on the pressure transmission surface 200 of the piezoelectric assembly 2, between the pressure transmission surface 200 and the square substrate 4, and the pressure on the pressure transmission surface 200 is transmitted to the square substrate 4 through the buffer pad 3.

[0066] Specifically, during the polishing process, the buffer pad 3 is located between the first pressing plate 21 and the square substrate 4. The pressure of the piezoelectric layer 20 is first transmitted to the first pressing plate 21, and then transmitted from the first pressing plate 21 to the square substrate 4 through the buffer pad 3. In one implementation, each piezoelectric assembly 2 can include a buffer pad 3, and the buffer pad 3 can be attached and fixed to the surface of the first pressing plate 21 away from the piezoelectric layer 20. In another implementation, as Figure 1 and Figure 19 shown, the buffer pad 3 covers the pressure transmission surfaces 200 of all the piezoelectric assemblies 2, and the shape of the buffer pad 3 is basically the same as the shape of the square substrate 4. Since the buffer pad 3 is a flexible pad with a certain thickness, even when it covers the pressure transmission surfaces 200 of all the piezoelectric assemblies 2, different piezoelectric assemblies 2 can still transmit pressure to the square substrate 4 separately through the buffer pad 3.

[0067] Since polishing liquid needs to be sprayed onto the square substrate 4 during the polishing process, and the piezoelectric assembly 2, as an electronic device, needs to avoid the polishing liquid directly contacting the piezoelectric layer 20 and the cables in the piezoelectric assembly 2. For this reason, in this embodiment, when the buffer pad 3 covers the pressure transmission surfaces 200 of multiple or all piezoelectric assemblies 2, the buffer pad 3 is wrapped around the piezoelectric assembly 2 to seal the annular side of the piezoelectric assembly 2 and the retaining ring 104, so as to avoid the polishing liquid directly contacting the piezoelectric assembly 2.

[0068] In one implementation, as Figures 1 to 4 shown, the polishing head includes: A support disk 101, which is used to connect with the machine table, and a wiring channel 6 is arranged in the support disk 101; The connecting plate 102 is fixed to one side of the supporting disk 101 facing the square substrate. There is a wiring space 5 between the connecting plate 102 and the supporting disk 101. The wiring channel 6 communicates with the wiring space 5 for the cable of the piezoelectric component 2 to pass through. The piezoelectric component 2 is fixed on the connecting plate 102.

[0069] In this embodiment, the supporting disk 101 is of a rigid structure, and the upper end of the supporting disk 101 is used to connect with the machine table. The connecting plate 102 is fixed to the lower end of the supporting disk 101. The connecting plate 102 and the supporting disk 101 can be fixed by bolts or welding, etc. Corresponding connecting holes 1012 can be preset on the supporting disk 101. In this embodiment, the supporting disk and the connecting plate form the rigid member 1 of the polishing head. There is a spacing between the upper surface of the connecting plate 102 and the supporting disk 101 to form the wiring space 5, and a wiring channel 6 communicating with the wiring space 5 is provided on the supporting disk 101. As Figure 17 and Figure 18 shown, the piezoelectric component 2 is fixed on the connecting plate 102. Specifically, the second pressing plate 22 in the piezoelectric component 2 is attached to the lower end surface of the connecting plate 102. The connecting column 25 passes through the hole position on the connecting plate 102 and enters the wiring space 5 and is threadedly connected with the nut 24. The cable connected to the piezoelectric layer 20 passes through the upper end of the connecting column 25 and then enters the wiring space 5, and then converges to the wiring channel 6 in the supporting disk 101 and is led out.

[0070] To fix the connecting plate 102 and form the wiring space 5 at the same time, as Figure 16 shown, a plurality of fixing columns 1020 are provided on one side of the connecting plate 102 facing the supporting disk 101. The ends of the fixing columns 1020 are fixedly connected to the supporting disk 101 so that there is a wiring space 5 between the connecting plate 102 and the supporting disk 101. The plurality of fixing columns 1020 can be arranged at intervals along the circumferential edge of the connecting plate 102.

[0071] Since pressure also needs to be separately applied to the polishing pad during the polishing process, in addition to the piezoelectric component 2 for applying pressure to the square substrate 4, the polishing head also needs a structure that can separately apply pressure to the polishing pad. For this purpose, as Figure 1 and Figure 4 shown, the connecting plate 102 in this embodiment further includes: A retaining ring 104 is movably connected to the supporting disk 101, so that the retaining ring 104 can move relative to the supporting disk 101 towards and away from the polishing pad. The retaining ring 104 is arranged on one side of the connecting plate 102 and surrounds the outside of the piezoelectric component 2. The retaining ring is used to confine the square substrate within the retaining ring; A driving member is used to drive the retaining ring 104 to move towards and away from the polishing pad.

[0072] Specifically, in this embodiment, the retaining ring 104 is installed at the lower end of the support disk 101. The retaining ring 104 has an opening matching the square substrate 4. Through this opening, the square substrate 4 can be accommodated, and at the same time, the square substrate 4 can be limited. When applied to the polishing of the square substrate 4, the retaining ring 104 is set as a square ring.

[0073] During the polishing process, it is necessary to separately transmit pressure to the polishing pad through the retaining ring 104. Therefore, the polishing head in this embodiment further includes a driving member, which drives the retaining ring 104 to move towards the polishing pad through the driving member, so as to transmit pressure to the polishing pad. The driving member can adopt any structure capable of outputting linear displacement, such as the airbag assembly 103, hydraulic cylinder assembly, etc. This embodiment does not limit it here.

[0074] For facilitating the flow of the polishing liquid, as Figure 4 shown, a plurality of liquid flow grooves 1040 are provided at one end of the retaining ring 104 close to the polishing pad.

[0075] In one embodiment, to reduce the overall weight of the polishing head, as Figure 4 shown, the driving member includes the airbag assembly 103. The first end of the airbag assembly 103 is connected to the support disk 101, and the second end of the airbag assembly 103 is connected to the retaining ring 104. The retaining ring 104 is driven to move through the expansion and contraction of the airbag assembly 103.

[0076] Specifically, in this embodiment, the airbag assembly 103 is connected between the support disk 101 and the retaining ring 104. An air path communicating with the airbag assembly 103 is provided on the support disk 101. By controlling the expansion of the airbag assembly 103, the retaining ring 104 is pushed towards the polishing pad to transmit pressure to the polishing pad. By controlling the contraction of the airbag assembly 103, the retaining ring 104 is pulled away from the polishing pad to release the square substrate 4.

[0077] When polishing the large-sized square substrate 4, the size of the retaining ring 104 is also large. Therefore, to enable the retaining ring 104 to transmit pressure to the polishing pad evenly, a plurality of airbag assemblies 103 are provided. The plurality of airbag assemblies 103 are arranged around the support disk 101. Taking the square retaining ring 104 as an example, at least one airbag assembly 103 can be provided on each side of the retaining ring 104, and preferably a plurality of airbag assemblies 103 are provided on each side.

[0078] As Figure 10 and Figure 11As shown, since the airbag assembly 103 needs to drive the retaining ring 104 to move through expansion and contraction, the airbag assembly 103 at least includes an airbag 1030. On this basis, since the airbag 1030 is a flexible bladder, in order to facilitate the connection between the airbag 1030 and the support disk 101 and the retaining ring 104, the airbag assembly 103 in this embodiment further includes a first connecting member 1031 and a second connecting member 1032; the first connecting member 1031 and the second connecting member 1032 are respectively fixed to the first end and the second end of the airbag 1030, the first connecting member 1031 is connected to the support disk 101, and the second connecting member 1032 is connected to the retaining ring 104.

[0079] In one embodiment, the airbag 1030 is a strip-shaped bladder. The lower end surface of the first connecting member 1031 is a plane and is adhesively fixed to the upper end surface of the airbag 1030. The upper end of the first connecting member 1031 is snap-connected or fixedly connected to the support disk 101 by bolts. The upper end surface of the second connecting member 1032 is a plane and is adhesively fixed to the lower end surface of the airbag 1030. The lower end of the second connecting member 1032 is snap-connected or fixedly connected to the support disk 101 by bolts. The pressure of the airbag 1030 is transmitted to the retaining ring 104 through the second connecting member 1032, and then transmitted to the polishing pad by the retaining ring 104.

[0080] To facilitate the connection between the airbag assembly 103 and the support disk 101 and the retaining ring 104, as Figure 4 shown, in this embodiment, a first connecting groove 8 is provided on the support disk 101, and a second connecting groove 9 is provided on the retaining ring 104. The first connecting member 1031 is fixedly fitted with the first connecting groove 8, and the second connecting member 1032 is fixedly fitted with the second connecting groove 9.

[0081] Specifically, the structure of the first connecting groove 8 can be designed according to the structure of the upper end of the first connecting member 1031. Similarly, the structure of the second connecting groove 9 can be designed according to the structure of the lower end of the second connecting member 1032. In one embodiment, the upper end of the first connecting member 1031 and the lower end of the second connecting member 1032 are T-shaped structures, and the corresponding first connecting groove 8 and second connecting groove 9 are T-shaped grooves. The first connecting groove 8 is provided along the edge of the support disk 101, and the second connecting groove 9 is provided along the edge of the retaining ring 104.

[0082] To further facilitate installation and disassembly, an installation opening is provided on the side surface of the support disk 101 and the side surface of the retaining ring 104. The installation opening is communicated with the corresponding first connecting groove 8 and second connecting groove 9. The first connecting member 1031 is inserted into the first connecting groove 8 through the corresponding installation opening, and the second connecting member 1032 is inserted into the second connecting groove 9 through the corresponding installation opening.

[0083] Specifically, in this embodiment, for each first connection groove 8 on each side of the support disk 101, an insertion port is provided at at least one end thereof, or insertion ports are provided at both ends. When insertion ports are provided at both ends, the first connection groove 8 is a through groove. The upper end of the first connecting member 1031 can be inserted into the first connection groove 8 through the corresponding insertion port. Similarly, the lower end of the second connecting member 1032 can be inserted into the second connection groove 9 through the corresponding insertion port.

[0084] Since the retaining ring 104 needs to be driven by the airbag 1030 to move, for facilitating the supply of air to the airbag 1030, as Figure 10 、 Figure 11 shown, in this embodiment, a first air passage 10310 is provided on the first connecting member 1031. As Figure 14 、 Figure 15 shown, a second air passage 1011 is provided on the support disk 101. The first air passage 10310 is communicated with the airbag 1030, and the second air passage 1011 is used for communicating with a pressure control source.

[0085] Since the airbag 1030 is a flexible bag body, it is not easy to restrict the offset of the retaining ring 104 in the horizontal direction, which may cause inaccurate linear movement of the retaining ring 104 in the axial direction. For this reason, as Figure 4 shown, the polishing head in this embodiment further includes a guiding structure 7. The first end of the guiding structure 7 is connected to the support disk 101, and the second end of the guiding structure 7 is connected to the retaining ring 104. The guiding structure 7 provides guidance for the movement of the retaining ring 104.

[0086] Specifically, the guiding structure 7 mainly serves to provide guidance for the movement of the retaining ring 104. The first end of the guiding structure 7 can be fixedly connected to the support disk 101, and the second end can be movably connected to the retaining ring 104. Or the first end of the guiding structure 7 can be movably connected to the support disk 101, and the second end can be fixedly connected to the retaining ring 104. The guiding structure 7 can be provided in multiple numbers and arranged at intervals along the circumferences of the support disk 101 and the retaining ring 104, so that the retaining ring 104 is evenly stressed during the movement process.

[0087] In one implementation manner, as Figure 15 and Figure 12 shown, the guiding structure 7 includes a guiding shaft 70. The guiding shaft 70 can be arranged between adjacent airbag assemblies 103. A guiding hole 1010 is provided on the support disk 101. The upper end of the guiding shaft 70 penetrates into the guiding hole 1010 and can slide, and the lower end of the guiding shaft 70 is assembled with the second connection groove 9 on the retaining ring 104 through a third connecting member 71. When the second connection groove 9 is a T-shaped groove, the third connecting member 71 includes a T-shaped connecting portion that can be assembled with the T-shaped groove.

[0088] In the present invention, the downward movement process of the polishing head is as follows: Before the buffer pad 3 contacts the square substrate 4, the airbag 1030 is in a negative pressure state, thus applying an upward pulling force to the retaining ring 104, overcoming the influence of the gravity of the retaining ring 104, and also being able to control the height difference between the bottom surface of the retaining ring 104 and the bottom surface of the buffer pad 3. During the descent of the polishing head, it is ensured that the retaining ring 104 contacts the polishing pad first. When the retaining ring 104 contacts the polishing pad, the negative pressure state in the airbag 1030 is released, and the airbag 1030 is kept in communication with the atmosphere. At this time, the polishing head continues to move until the polishing pad contacts the square substrate 4. During this process, the airbag 1030 is squeezed by the support disk 101. Since the airbag 1030 is in communication with the atmosphere, the airbag 1030 can deform to enable the support disk 101 to drive the piezoelectric assembly 2 and the buffer pad 3 to continue to move downward. During the polishing process, the airbag 1030 is inflated to maintain a positive pressure to transmit pressure to the polishing pad.

[0089] According to another aspect of the present invention, there is provided a polishing apparatus including the above-mentioned polishing head.

[0090] According to another aspect of the present invention, there is provided a polishing method using the above-mentioned polishing head, and the method includes: Dividing the square substrate 4 into a plurality of polishing regions, and each polishing region corresponds to at least one piezoelectric assembly 2; Determining the speed of each polishing region during the polishing process; According to the speed of the polishing region, controlling the input voltage of the piezoelectric assembly 2 to change the pressure transmitted by the piezoelectric assembly 2 to the polishing region, so that the square substrate achieves the target material removal rate.

[0091] During the polishing process, according to the corresponding relationship among the input voltage of the piezoelectric assembly 2, the speed of the region on the square substrate 4 corresponding to the piezoelectric assembly 2, and the material removal rate of the polishing region on the square substrate 4 corresponding to the piezoelectric assembly 2, adjusting the input voltage to achieve the target material removal rate.

[0092] Among them, according to the speed of the polishing region, controlling the input voltage of the piezoelectric assembly, and changing the pressure transmitted by the piezoelectric assembly to the polishing region, specifically: By the following corresponding relationship, the square substrate achieves the target material removal rate:

[0093] Among them, is the material removal rate of the polishing region on the square substrate 4 corresponding to the piezoelectric assembly 2, is the Preston constant, is the speed of the polishing region on the square substrate 4 corresponding to the piezoelectric assembly 2, is the surface area of the piezoelectric material in the piezoelectric assembly 2, is the elastic modulus of the piezoelectric material when the electric field is zero or constant, is the input voltage of the piezoelectric component 2, is the piezoelectric constant, is the thickness of the piezoelectric material, is the surface area of the pressure transmission surface 200 on the piezoelectric component 2.

[0094] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A polishing head for polishing a square substrate, characterized in that, Comprising: a connecting plate and a plurality of piezoelectric components; wherein, The plurality of piezoelectric components are arranged on the connecting plate and are located between the connecting plate and the square substrate to be polished. The piezoelectric component has a pressure transmission surface for transmitting pressure to the square substrate. The pressure transmission surfaces of different piezoelectric components are used to transmit pressure to different polishing areas of the square substrate, so as to adjust the input voltage of the piezoelectric component according to the speed of different polishing areas of the square substrate during the polishing process to control the pressure transmitted from the pressure transmission surface to the corresponding polishing area of the square substrate.

2. The polishing head according to claim 1, characterized in that, The plurality of piezoelectric components are arranged in a matrix manner in accordance with the shape of the square substrate.

3. The polishing head according to claim 2, characterized in that, The plurality of piezoelectric components uniformly cover the square substrate in accordance with the shape of the square substrate.

4. The polishing head according to claim 1, wherein During the polishing process, according to the speed of different polishing areas of the square substrate, adjusting the input voltage of the piezoelectric component to control the pressure transmitted from the pressure transmission surface to the corresponding polishing area of the square substrate is specifically as follows: The square substrate is divided into a plurality of polishing areas, and each polishing area corresponds to at least one of the piezoelectric components, and the speed of each polishing area during the polishing process is determined; According to the speed of the polishing area, controlling the input voltage of the piezoelectric component to change the pressure transmitted from the piezoelectric component to the polishing area, so that the square substrate reaches the target material removal rate.

5. The polishing head according to claim 1, wherein The controlling the input voltage of the piezoelectric component according to the speed of the polishing area to change the pressure transmitted from the piezoelectric component to the polishing area is specifically as follows: Through the following corresponding relationship, the square substrate reaches the target material removal rate: , Among them, is the material removal rate of the polishing area corresponding to the piezoelectric component on the square substrate, is the Preston constant, is the speed of the polishing area corresponding to the piezoelectric component on the square substrate, is the surface area of the piezoelectric material in the piezoelectric component, is the elastic modulus of the piezoelectric material when the electric field is zero or constant, is the input voltage of the piezoelectric component, is the piezoelectric constant, is the thickness of the piezoelectric material, is the surface area of the pressure transmission surface on the piezoelectric component.

6. The polishing head according to claim 1, wherein, The piezoelectric component includes a piezoelectric layer and a first pressing plate. The piezoelectric layer is located between the connecting plate and the first pressing plate, so that the first pressing plate applies a pre-tightening force to the piezoelectric layer, and the piezoelectric layer transmits pressure to the square substrate through the first pressing plate.

7. The polishing head according to claim 6, characterized in that The piezoelectric component further includes a connecting column. The first end of the connecting column is fixedly connected to the first pressing plate, and the second end of the connecting column passes through the piezoelectric layer and is fixedly connected to the connecting plate. By adjusting the axial fixed position of the connecting column on the connecting plate, the magnitude of the pre-tightening force applied by the first pressing plate to the piezoelectric layer is changed.

8. The polishing head according to claim 7, wherein, The stiffness of the first pressing plate is greater than that of the connecting column. During the pressure transmission process, the connecting column generates an axial elastic deformation under the pressure of the piezoelectric layer to provide the displacement amount required for the first pressing plate to transmit pressure.

9. The polishing head according to claim 8, wherein, The connecting column is a hollow columnar structure, and a wire routing hole is provided on the connecting column. The cable connected to the piezoelectric layer enters the connecting column through the wire routing hole and extends out from the second end of the connecting column into the wire routing space above the connecting plate.

10. The polishing head according to claim 6, characterized in that, The piezoelectric component further includes a second pressing plate. The second pressing plate is arranged between the connecting plate and the piezoelectric layer, and the second end of the connecting column passes through the second pressing plate and is fixedly connected to the connecting plate.

11. The polishing head according to claim 1, wherein It further includes a buffer pad. The buffer pad is arranged between the pressure transmission surface of the piezoelectric component and the square substrate, and the pressure on the pressure transmission surface is transmitted to the square substrate through the buffer pad.

12. The polishing head according to claim 11, characterized in that, It further includes a retaining ring which is arranged on one side of the connecting plate and is used to confine the square substrate within the retaining ring.

13. The polishing head according to claim 12, wherein, The buffer pad covers the pressure transfer surfaces of a plurality of the piezoelectric components, wraps around the piezoelectric components, and seals between the ring side of the piezoelectric components and the retaining ring.

14. The polishing head according to claim 13, wherein, The polishing head further includes a driving member which is used to drive the retaining ring to move towards and away from the polishing pad.

15. The polishing head according to claim 14, wherein, The driving member includes an airbag assembly which is connected to the retaining ring, and drives the retaining ring to move through the expansion and contraction of the airbag assembly.

16. The polishing head according to claim 15, wherein The airbag assemblies are provided in plurality, and the plurality of airbag assemblies are arranged around the retaining ring.

17. The polishing head according to claim 15, wherein, The airbag assembly includes an airbag, a first connecting member, and a second connecting member. The first connecting member and the second connecting member are respectively fixed to the first end and the second end of the airbag, and the second connecting member is connected to the retaining ring.

18. The polishing head according to claim 17, characterized in that, The polishing head further includes: A support disk which is used to connect with the machine table, and a wire routing channel is arranged inside the support disk, and the first connecting member is connected to the support disk. The connecting plate is fixed on one side of the support disk facing the square substrate, and there is a wire routing space between the connecting plate and the support disk. The wire routing channel is communicated with the wire routing space for the cable of the piezoelectric component to pass through.

19. The polishing head according to claim 18, wherein, On one side of the connecting plate facing the support disk, a plurality of fixing columns are arranged, and the ends of the fixing columns are fixedly connected to the support disk so that there is the wire routing space between the connecting plate and the support disk.

20. The polishing head according to claim 18, characterized in that, A first connecting groove is arranged on the support disk, and a second connecting groove is arranged on the retaining ring. The first connecting member is fixedly fitted with the first connecting groove, and the second connecting member is fixedly fitted with the second connecting groove.

21. The polishing head according to claim 20, wherein, Loading ports are arranged on the side surfaces of the support disk and the retaining ring. The loading ports are communicated with the corresponding first connecting groove and second connecting groove. The first connecting member is loaded into the first connecting groove through the corresponding loading port, and the second connecting member is loaded into the second connecting groove through the corresponding loading port.

22. The polishing head according to claim 18, wherein, A first air duct is arranged on the first connecting member, and a second air duct is arranged on the support disk. The first air duct is communicated with the airbag, and the second air duct is used to be communicated with a pressure control source.

23. The polishing head according to claim 18, wherein It further includes a guiding structure. The first end of the guiding structure is connected to the support disk, and the second end of the guiding structure is connected to the retaining ring. The guiding structure provides guidance for the movement of the retaining ring.

24. The polishing head according to claim 23, characterized in that, The guiding structure includes a guiding shaft. A third connecting member is arranged at the second end of the guiding shaft. The third connecting member is fixedly fitted with the second connecting groove. A guiding hole is arranged on the support disk, and the upper end of the guiding shaft is slidably connected to the guiding hole.

25. A polishing device, characterized in that, It includes the polishing head according to any one of claims 1 to 24.

26. A polishing method, characterized in that, Adopting the polishing head according to any one of claims 1 to 24, the method includes: Dividing the square substrate into a plurality of polishing areas, and each polishing area corresponds to at least one of the piezoelectric components. Determining the speed of each polishing area during the polishing process. Control the input voltage of the piezoelectric component according to the speed of the polishing area, and change the pressure transmitted by the piezoelectric component to the polishing area, so that the square substrate reaches the target material removal rate.

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