Polishing head, polishing system and control method of polishing system

Abstract

The invention provides a polishing head, a polishing system and a control method of the polishing system. The polishing head comprises a retaining ring and a back film, the retaining ring and the back film are both installed on the body, the retaining ring surrounds the periphery of the back film, the polishing head further comprises a shape compensation plate, the shape compensation plate is installed on the bottom face of the back film and comprises a plurality of control point positions, and a wafer fixing cavity is formed between the shape compensation plate and the retaining ring. The shape compensation plate is used for being electrically connected with a deformation controller, and the deformation controller can control at least one control point to stimulate the shape compensation plate, so that the shape compensation plate deforms at the local part where the control point is located. The polishing system is provided with the polishing head, the invention further provides a working method of the polishing system, the polishing head can ensure the flatness of the wafer during polishing, the polishing thickness of the wafer is uniform, and the product yield is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wafer processing equipment, and in particular to a polishing head, a polishing system provided with the polishing head, and a control method of the polishing system. Background Art

[0002] The polishing head is one of the key components of chemical mechanical polishing (CMP) equipment. It is used to fix and carry the workpiece to be polished (such as a wafer, etc.), and at the same time exert a certain pressure on the workpiece to ensure that the workpiece is in close contact with the polishing pad. Figure 1 As shown, the existing polishing head 91 includes a main body 911, a retaining ring 912, a back film 913, a rotary actuator 914, etc. The retaining ring 912 and the back film 913 are both installed on the main body 911, and the retaining ring 912 surrounds the outer circumference of the back film 913 and forms a wafer fixing cavity 910 between the back film 913. The driving end of the rotary actuator 914 is connected to the main body 911 to drive the main body 911 to rotate around the axis of the main body 911. When the polishing head 91 grabs the wafer 90 for polishing, the back film 913 generates negative pressure under the action of the first gas flow path 9111 and the vacuum adsorption unit 92 to adsorb and fix the wafer 90 in the wafer fixing chamber 910; then, the pressure of the back film 913 is adjusted by the second gas flow path 9112 and the first pressure regulating unit 93, and the pressure of the retaining ring 912 is adjusted by the third gas flow path 9113 and the second pressure regulating unit 94 (the retaining ring 912 can slide relative to the main body 911 in its own axial direction); then, the polishing head 91 drives the wafer 90 to move toward the polishing pad 95 until the wafer 90 contacts the polishing pad 95; then, the rotary actuator 914 drives the main body 911 to rotate, and the rotation direction of the main body 911 is opposite to the rotation direction of the turntable 96 (the polishing pad 95 is installed on the turntable 96); but after the grinding is completed, the polishing head 91 moves to the specified position or the initial position. However, the existing polishing head 91 has the disadvantage that the back film 913 can only ensure the uniformity of the force on the back film 913 under the action of the first gas flow path 9111, but cannot ensure the flatness of the wafer 90. Therefore, there is a problem of uneven polishing thickness of the wafer 90, which affects the product yield. Summary of the invention

[0003] In order to solve the above problems, the first object of the present invention is to provide a polishing head that can ensure the flatness of the wafer during polishing, make the wafer polishing thickness uniform, and improve the product yield.

[0004] A second object of the present invention is to provide a polishing system equipped with the above-mentioned polishing head.

[0005] The third object of the present invention is to provide a control method for the above-mentioned polishing system.

[0006] In order to achieve the main purpose of the present invention, the present invention provides a polishing head, including a retaining ring and a back film, both of which are installed on the main body, and the retaining ring surrounds the outer circumference of the back film, wherein the polishing head also includes a shape compensation plate, the shape compensation plate is installed on the bottom surface of the back film, the shape compensation plate includes multiple control points, and a wafer fixing cavity is formed between the shape compensation plate and the retaining ring; the shape compensation plate is used to be electrically connected to a deformation controller, and the deformation controller can control at least one control point to stimulate the shape compensation plate, so that the shape compensation plate is deformed at the local location of the control point.

[0007] As can be seen from the above, the polishing head can cooperate with the detection unit of the polishing system to detect the flatness of the surface of the wafer grasped by the polishing head, and the control unit of the polishing system can control the relevant control points on the shape compensation plate through the deformation controller to stimulate (such as by changing the temperature, current, magnetic field, etc.) the shape compensation plate, so that the shape compensation plate is deformed locally at the relevant control points to compensate for the recessed parts of the wafer, thereby keeping the surface of the wafer flat and ensuring the uniformity of the wafer polishing; through the design of the polishing head, the problem that the existing polishing head can only ensure the uniformity of the force on the wafer (guaranteed by the uniform force on the back film), but cannot ensure the flatness of the wafer and make the wafer polishing thickness uniform is effectively solved, thereby improving the product yield.

[0008] A further solution is that the shape compensation plate further includes a memory layer, and when the memory layer is stimulated by the control point, the memory layer is deformed locally where the control point is located; the memory layer is a bidirectional shape memory polymer or a bidirectional shape memory alloy.

[0009] As can be seen from the above, through the design of the memory layer, the memory layer can be directionally deformed and restored after being stimulated by the control point, and the degree of deformation can change according to the change of the degree of stimulation.

[0010] A further solution is that the control point is a heater, the deformation controller is a temperature controller, and the heater generates heat when controlled by the temperature controller; or the control point is a discharger, and the discharger generates current when controlled by the deformation controller.

[0011] As can be seen from the above, by setting the control point as a heater, the amount of heat generated by the heater (i.e., controlling the temperature of the heater) can be controlled by a temperature controller to stimulate the memory layer to undergo directional deformation; or, by setting the control point as a discharger, the size of the current released by the discharger can be controlled by a deformation controller to stimulate the memory layer to undergo directional deformation.

[0012] A further solution is that the shape compensation plate also includes a protective layer, which wraps the memory layer and the control points.

[0013] It can be seen from the above that the protective layer can prevent the shape compensation plate from scratching the surface of the wafer when it contacts the wafer, thereby protecting the wafer.

[0014] A further solution is that when the polishing head grabs the wafer, the wafer fits into the bottom surface of the shape compensation plate, and the memory layer is arranged close to the side of the shape compensation plate facing the wafer; the local deformation of the memory layer can force the corresponding position on the wafer to deform in a deformation direction that is basically the same as the local deformation of the memory layer.

[0015] It can be seen from the above that by designing the position of the memory layer, the memory layer can better control the local position of the wafer, thereby keeping the surface of the wafer to be polished flat.

[0016] A further solution is that the shape compensation plate has a vacuum adsorption portion or an electrostatic adsorption portion for adsorbing the wafer.

[0017] As can be seen from the above, this design can ensure that the polishing head clamps and fixes the wafer so as to move the wafer.

[0018] A further solution is that the shape compensation plate is a two-way shape memory plate.

[0019] As can be seen from the above, this design enables the shape compensation plate to switch between a single or multiple temporary shapes and permanent shapes when subjected to external stimuli, thereby improving the compensation accuracy of the shape compensation plate to better ensure the flatness of the wafer's surface to be polished.

[0020] In order to achieve the second purpose of the present invention, the present invention provides a polishing system, including the above-mentioned polishing head, a deformation controller, a detection unit, a mobile actuator and a rotary actuator, the deformation controller is electrically connected to the shape compensation plate, the detection unit is used to detect the flatness of the surface of the wafer grasped by the polishing head, the mobile actuator can drive the polishing head and / or the detection unit to move, and the rotary actuator can drive the polishing head and / or the polishing pad to rotate so that the side of the wafer away from the shape compensation plate is in contact with the polishing pad for grinding.

[0021] As can be seen from the above, the detection unit is used to detect the flatness of the wafer surface before the wafer is polished, and then cooperate with the control unit to control the relevant control points on the shape compensation plate through the deformation controller to stimulate (such as by changing the temperature, current, magnetic field, etc.) the shape compensation plate, so that the shape compensation plate is deformed locally at the relevant control points to compensate for the recessed parts of the wafer, thereby keeping the surface of the wafer flat and ensuring the uniformity of the wafer polishing; this polishing system effectively solves the problem that the existing polishing head can only ensure the uniformity of the wafer force (guaranteed by the uniform force of the back film), but cannot guarantee the flatness of the wafer or make the wafer polishing thickness uniform, thereby improving the product yield.

[0022] A further solution is that the detection unit is a graphic sensor, a confocal sensor, a laser displacement sensor, a 3D laser profile sensor or a 3D vision sensor.

[0023] It can be seen from the above that the above design can ensure that the detection unit can detect the flatness of the surface of the grasped wafer, and accurately identify the depression position and depression depth of the surface of the grasped wafer, so that the control unit can control the corresponding control point through the deformation controller to stimulate the memory layer to deform, and then compensate for the depression on the surface of the grasped wafer.

[0024] A further solution is that there is a first pressure chamber between the main body of the polishing head and the retaining ring, and a second pressure chamber between the main body and the back film; a first gas flow path and a second gas flow path are provided on the main body, the first gas flow path is connected to the first pressure chamber, and the second gas flow path is connected to the second pressure chamber.

[0025] As can be seen from the above, the first pressure chamber is connected to the first pressure regulating unit of the retaining ring through the first gas flow path to adjust the pressure of the retaining ring; the second pressure chamber is connected to the second pressure regulating unit of the back film through the second gas flow path to adjust the pressure of the back film; the air holes of the bidirectional shape memory plate are connected to the vacuum adsorption unit through the third gas flow path to enable the bidirectional shape memory plate to adsorb or release the wafer.

[0026] In order to achieve the third purpose of the present invention, the present invention provides a control method for a polishing system, wherein the polishing system is the above-mentioned polishing system, and the control method includes: controlling the moving actuator to drive the polishing head and / or the detection unit to move relative to each other; obtaining the flatness data of the surface to be polished of the wafer grasped by the polishing head detected by the detection unit; and controlling at least one control point to stimulate the shape compensation plate through a deformation controller according to the flatness data, so that the stimulated part of the shape compensation plate is deformed to adjust the flatness of the surface to be polished.

[0027] As can be seen from the above, before the wafer is polished, the flatness of the surface of the wafer grasped by the polishing head is detected by the detection unit, and the position and depth of the depression on the wafer surface are fed back to the control unit, so that the control unit controls the relevant control points on the shape compensation plate through the deformation controller to stimulate (such as by changing the temperature, current, magnetic field, etc.) the shape compensation plate, so that the shape compensation plate is deformed locally at the relevant control points to compensate for the depressions of the wafer, thereby keeping the surface of the wafer flat and ensuring the uniformity of the wafer polishing; this control method effectively solves the problem that the existing polishing head can only ensure the uniformity of the force on the wafer (guaranteed by the uniform force on the back film), but cannot ensure the flatness of the wafer or make the polishing thickness of the wafer uniform, thereby improving the product yield.

[0028] A preferred solution is the step of obtaining flatness data of the surface to be polished of the wafer grasped by the polishing head and detected by the detection unit, comprising: the detection unit obtains height change data between the surface to be polished and the detection unit and wafer thickness change data to confirm the depression position and depression depth of the surface to be polished.

[0029] Another preferred scheme is the step of causing the stimulated part of the shape compensation plate to deform so as to adjust the flatness of the surface to be polished, comprising: controlling the point positions to stimulate the shape compensation plate in a manner matching the depth of the depression on the wafer, so that the shape compensation plate, under the stimulation of the control point positions, deforms in a manner matching the degree of stimulation, thereby pushing the depressed part of the wafer, forcing the corresponding position on the wafer to deform in a deformation direction substantially the same as the local deformation of the shape compensation plate, so that the surface to be polished of the wafer remains flat as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a system schematic diagram of an existing polishing system.

[0031] Figure 2 Schematic diagram of the polishing system according to the first embodiment of the present invention.

[0032] Figure 3 It is a schematic diagram of the bidirectional shape memory plate of the first embodiment of the polishing system of the present invention with some components omitted.

[0033] Figure 4 It is a partial cross-sectional schematic diagram of the bidirectional shape memory plate of the first embodiment of the polishing system of the present invention.

[0034] Figure 5 It is a partial cross-sectional schematic diagram of the bidirectional shape memory plate of the first embodiment of the polishing system of the present invention when it contains an elastic layer.

[0035] The present invention is further described below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0036] Polishing system first embodiment Reference Figure 2 The polishing system 100 includes a polishing head 101, a deformation controller 102, a detection unit 103, a turntable 104, a polishing pad 105, a rotary actuator, a moving actuator 107, a first pressure regulating unit 108, a second pressure regulating unit 109, a vacuum adsorption unit 110 and a control unit (not shown). The rotary actuator preferably includes a first rotary actuator 5 and a second rotary actuator 106, The polishing head 101 includes a main body 1, a retaining ring 2, a back film 3 and a deformation compensation plate; a first gas flow path 11, a second gas flow path 12 and a third gas flow path 13 are provided on the main body 1; the retaining ring 2 and the back film 3 are both installed below the main body 1, and the retaining ring 2 is arranged around the outer periphery of the back film 3, wherein the retaining ring 2 has a sliding space with the main body 1 in its axial direction, and a first pressure chamber 20 is formed between the retaining ring 2 and the main body 1, and the first pressure chamber 20 is connected to the first gas flow path 11; a second pressure chamber 30 is formed between the back film 3 and the main body 1, and the second pressure chamber 30 is connected to the second gas flow path 12.

[0037] In this embodiment, the deformation compensation plate is preferably a bidirectional shape memory plate 4; of course, in other embodiments, the deformation compensation plate may also be a unidirectional shape memory plate. The bidirectional shape memory plate 4 is installed on the bottom surface of the backing film 3, and a wafer fixing cavity 40 is formed between the bidirectional shape memory plate 4 and the retaining ring 2. The wafer fixing cavity 40 is used to fix and limit the wafer. Figure 3 The bidirectional shape memory plate 4 preferably includes a plurality of control points 41, a memory layer 42 and a protective layer 43. The bidirectional shape memory plate 4 is used to be electrically connected to the deformation controller 102, and the deformation controller 102 can control at least one control point 41 to stimulate the bidirectional shape memory plate 4, so that the bidirectional shape memory plate 4 is deformed at the location of the control point 41.

[0038] Specifically, the memory layer 42 is preferably a two-way shape memory polymer or a two-way shape memory alloy, so that the memory layer 42 is deformed locally at the control point 41 when stimulated by the control point 41. Among them, two-way shape memory polymers (2W-SMPs) are materials that can switch between a single or multiple temporary shapes and permanent shapes when subjected to external stimuli (such as temperature changes, current changes, magnetic field changes, etc.), for example, when subjected to different degrees of stimulation, the material can memorize the shape in two or more directions, that is, they can switch between multiple temporary shapes and permanent shapes under different degrees of external stimulation; similarly, a two-way shape memory alloy is also a material that can switch between a single or multiple temporary shapes and permanent shapes when subjected to external stimuli (such as temperature changes, current changes, magnetic field changes, etc.), for example, when subjected to different degrees of stimulation, the material can switch back and forth between two or more shapes to achieve a transition from a temporary shape to a permanent shape and from a permanent shape to a temporary shape. It should be noted that the above-mentioned two-way shape memory polymer or two-way shape memory alloy is prior art and is a material that is well known to the public, so it will not be described in detail here.

[0039] In this embodiment, the control point 41 is preferably a heater, and the deformation controller 102 is preferably a temperature controller, so that the deformation controller 102 can control the local deformation of the memory layer 42 where the point is located by controlling the heat generated by the heater (i.e., the control point 41) (i.e., controlling the temperature of the heater). For example, when the temperature controller controls the heater to stop heating, the memory layer 42 gradually recovers to a permanent state (i.e., the initial state, in which the surface of the memory layer 42 remains flat, and the surface of the two-way shape memory plate 4 in contact with the wafer 10 also remains flat); when the temperature controller controls the heater to heat up below the limit temperature (the memory layer 42 will not continue to deform beyond the limit temperature), the deformation amplitude of the memory layer 42 in the local area where the heater is located increases; when the temperature controller controls the heater to cool down below the limit temperature, the deformation amplitude of the memory layer 42 in the local area where the heater is located decreases; it can be seen that the memory layer 42 can be directional deformed and restored after being stimulated by the control point 41, and the degree of deformation can change according to the change of the degree of stimulation.

[0040] Combination Figure 4 , the protective layer 43 wraps the memory layer 42 and the control point 41. The protective layer 43 can prevent the bidirectional shape memory plate 4 from scratching the surface of the wafer 10 when it contacts the wafer 10, so as to protect the wafer 10. Preferably, the protective layer 43 has the ability of elastic deformation (that is, it deforms and stores energy when subjected to external force, and recovers to its initial state under the action of its own potential energy when not subjected to external force). By making the protective layer 43 have the ability of elastic deformation, it helps to assist the memory layer 42 to recover to a permanent state; when a part of the memory layer 42 is deformed, the deformed part of the memory layer 42 will also drive a part of the protective layer 43 to deform. And / or, such as Figure 5 As shown, an elastic layer 44 may be provided between the memory layer 42 and the protective layer 43, and the elastic layer 44 has the ability of elastic deformation to assist the memory layer 42 in restoring to a permanent state. When a part of the memory layer 42 is deformed, the deformed part of the memory layer 42 will also drive a part of the elastic layer 44 to deform.

[0041] When the polishing head 101 grabs the wafer 10, the wafer 10 fits the bottom surface of the shape compensation plate (such as the bottom surface of the protective layer 43 in this embodiment), and the memory layer 42 is arranged close to the side of the bidirectional shape memory plate 4 facing the wafer 10. It can be understood that, in this embodiment, part of the protective layer 43 is located between the memory layer 42 and the wafer 10, so that the local deformation of the memory layer 42 can force the corresponding position on the wafer 10 (such as the recessed portion corresponding to the deformed portion on the memory layer 42) to deform in a deformation direction that is basically the same as the local deformation of the memory layer 42.

[0042] In addition, the bidirectional shape memory plate 4 has a vacuum adsorption portion or an electrostatic adsorption portion for adsorbing the wafer. Preferably, the bidirectional shape memory plate 4 is provided with a vacuum adsorption portion, and the vacuum adsorption portion includes a plurality of air holes, and the air holes are connected to the third air path on the main body 1; wherein, the setting principle and function of the air holes in the bidirectional shape memory plate 4 are the same as the principle and function of the air holes in the existing back film 3 mentioned above, so they will not be elaborated here.

[0043] The output end of the first rotary actuator 5 is connected to the main body 1 to drive the main body 1 to rotate around the rotation axis of the main body 1 itself, even if the main body 1 is in a self-rotation state.

[0044] The deformation controller 102 is electrically connected to the control unit to control the control point 41 to stimulate the memory layer 42 to a corresponding degree according to the control signal generated by the control unit, thereby causing the memory layer 42 to deform to a desired degree.

[0045] The detection unit 103 is electrically connected to the control unit. The detection unit 103 is used to detect the surface flatness of the wafer 10 grasped by the polishing head 101, and identify the depression position and depression depth on the surface of the wafer 10, and then generate detection data and send it to the control unit, so that the control unit can control the deformation controller 102 according to the detection data, and then the deformation controller 102 controls the relevant control point positions 41 located at the depression on the surface of the wafer 10, so that the control point positions 41 stimulate the memory layer 42 to a specific degree that matches the depression depth of the corresponding depression, so that the depression of the wafer 10 is compensated by the deformation of the memory layer 42 of the bidirectional shape memory plate 4 and presents a flat state with other parts of itself (wafer 10). Among them, the detection unit 103 is preferably a graphic sensor, a confocal sensor, a laser displacement sensor, a 3D laser profile sensor or a 3D vision sensor, so as to ensure that the detection unit 103 can accurately identify the depression position and depression depth on the surface of the wafer 10 grasped by the polishing head 101, thereby ensuring that the control unit can control the corresponding control point 41 through the deformation controller 102 to stimulate the memory layer 42 to deform, thereby ensuring the compensation accuracy of the depression on the surface of the wafer 10.

[0046] The polishing pad 105 is installed on the turntable 104, and the polishing pad 105 is used to polish the surface of the wafer 10; the driving end of the second rotary actuator 106 is connected to the turntable 104 to drive the turntable 104 to rotate around the rotation axis of the turntable 104, so that the turntable 104 is in a self-rotating state, and the second rotary actuator 106 is electrically connected to the control unit; wherein, the rotation direction of the turntable 104 is opposite to the rotation direction of the polishing head 101, so as to improve the uniformity of polishing the wafer 10, improve the surface quality of the wafer 10 and optimize the polishing efficiency.

[0047] The moving actuator 107 is used to drive the polishing head 101 and / or the detection unit 103 to move. For example, in the present embodiment, the driving end of the moving actuator 107 is connected to the first rotary actuator 5 of the polishing head 101, and the moving brake 107 is used to drive the polishing head 101 to move relative to the detection unit 103, so that the detection unit 103 can accurately and comprehensively detect the surface flatness of the wafer 10 grasped by the polishing head 101; at the same time, the moving actuator 107 is also used to drive the polishing head 101 to move relative to the polishing pad 105, so that the surface of the wafer 10 contacts the polishing pad 105, so that the polishing pad 105 polishes the surface of the wafer 10, or after completing the polishing of the surface of the wafer 10, drives the polishing head 101 to grasp the wafer 10 and move it to a specified position.

[0048] The first pressure regulating unit 108 is used to be connected to the first gas flow path 11 to regulate the pressure of the retaining ring 2 through the first gas flow path 11 and the first pressure chamber 20; the second regulating unit is used to be connected to the second gas flow path 12 to regulate the pressure of the back film 3 through the second gas flow path 12 and the second pressure chamber 30; the vacuum adsorption unit 110 is used to be connected to the third gas flow path 13 to generate negative pressure at the pores of the bidirectional shape memory plate 4 through the third gas flow path 13 to grab the wafer 10, or to release the negative pressure state at the pores of the bidirectional shape memory plate 4 to release the wafer 10.

[0049] In summary, it can be seen that through the design of the polishing system 100, the detection unit 103 first detects the flatness of the surface of the wafer 10 before polishing the wafer 10, and then the control unit controls the relevant control point 41 on the two-way shape memory plate 4 through the deformation controller 102 through the detection data of the detection unit 103 to stimulate (such as by changing the temperature, current, magnetic field, etc.) the memory layer 42 of the two-way shape memory plate 4, so that the two-way shape memory plate 4 is deformed at the location of the relevant control point 41 to compensate for the concave part of the wafer 10, so as to keep the surface of the wafer 10 flat and ensure the uniformity of the polishing of the wafer 10. At the same time, the polishing system 100 effectively solves the problem that the existing polishing head 101 can only ensure the uniformity of the force on the wafer 10 (guaranteed by the uniform force on the back film 3), but cannot ensure the flatness of the wafer 10 and make the polishing thickness of the wafer 10 uniform, thereby improving the product yield.

[0050] Polishing system second embodiment The difference between this embodiment and the first embodiment of the polishing system lies in the stimulation method of the memory layer. Specifically, in this embodiment: The control point is a discharger, and the deformation controller is a current controller for controlling the discharge current of the discharger, so that a current of a specific magnitude is generated when the discharger is controlled by the current controller. It can be seen that by setting the control point as a discharger, the current controller can be used to control the current size released by the discharger to stimulate the memory layer to deform to a corresponding degree.

[0051] Embodiment of control method of polishing system The control method of this embodiment is applied to the polishing system described in the first embodiment or the second embodiment of the polishing system, and the control method includes: The moving actuator 107 is controlled to drive the polishing head 101 to move to the wafer 10 , and the vacuum adsorption unit 110 is controlled to generate negative pressure at the air holes of the bidirectional shape memory plate 4 to grab the wafer 10 .

[0052] The movable actuator 107 is controlled to drive the polishing head 101 to move relative to the detection unit 103; before polishing the wafer 10, the polishing head 101 is controlled to grab the wafer 10 and move relative to the detection unit 103, so that the detection unit 103 detects the flatness of the surface to be polished of the grabbed wafer 10, so as to detect whether there is any depression on the surface to be polished of the wafer 10, and the depth of the depression.

[0053] The flatness data of the wafer 10 caught by the polishing head 101 detected by the detection unit 103 is obtained, and the flatness data is generated and sent to the control unit; the flatness data includes the concave position and concave depth of the surface to be polished of the wafer 10.

[0054] According to the flatness data, at least one control point 41 is controlled by the deformation controller 102 to stimulate the bidirectional shape memory plate 4, so that the stimulated part of the bidirectional shape memory plate 4 is deformed; the control unit controls the control point 41 of the concave surface of the wafer 10 to be polished through the deformation controller 102 according to the flatness data sent by the detection unit 103, so that the control point 41 stimulates the memory layer 42 of the bidirectional shape memory plate 4 to match the depth of the concave part, and then the memory layer 42 is deformed to match the degree of stimulation under the stimulation of the control point 41, and then pushes the concave part of the wafer 10, so that the surface of the wafer 10 to be polished remains flat as a whole, so that the polishing thickness of the wafer 10 is uniform. Among them, the adjustment accuracy of the bidirectional shape memory plate 4 on the surface flatness of the wafer 10 to be polished can be improved by increasing the number of control points 41 of the bidirectional shape memory plate 4.

[0055] Control the first pressure regulating unit 108 to regulate the pressure of the retaining ring 2 so that the pressure of the retaining ring 2 reaches a set value, so as to ensure the stability of the wafer 10 during the polishing process, optimize the polishing effect and protect the edge of the wafer 10; and control the second pressure regulating unit 109 to regulate the pressure of the back film 3 so that the pressure of the back film 3 reaches a set value, so that the force on the wafer 10 is uniform during the polishing process, so as to ensure that the pressure distribution when the surface of the wafer 10 contacts the polishing pad 105 is more uniform, and the polishing efficiency is improved.

[0056] The moving actuator 107 is controlled to drive the polishing head 101 to move to the polishing pad 105 until the polished surface of the wafer 10 contacts the polishing pad 105 .

[0057] The first rotary actuator 5 of the polishing head 101 is controlled to drive the main body 1 to rotate, and the second rotary actuator 106 is controlled to drive the turntable 104 to rotate. The rotation direction of the main body 1 is opposite to that of the turntable 104 .

[0058] After the polishing process of the wafer 10 is completed, the moving actuator 107 is controlled to move to a designated position to release the wafer 10 .

[0059] Finally, it should be emphasized that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A polishing head, comprising a retaining ring and a backing film, wherein the retaining ring surrounds the outer periphery of the backing film, and wherein: The polishing head further comprises a shape compensation plate, the shape compensation plate is mounted on the bottom surface of the backing film, the shape compensation plate comprises a plurality of control points, and a wafer fixing cavity is formed between the shape compensation plate and the retaining ring; The shape compensation plate is used to be electrically connected to the deformation controller, and the deformation controller can control at least one of the control points to stimulate the shape compensation plate, so that the shape compensation plate is deformed at the location of the control point.

2. The polishing head according to claim 1, characterized in that: The shape compensation plate further comprises a memory layer, and when the memory layer is stimulated by the control point, the memory layer is deformed at the local area where the control point is located.

3. The polishing head according to claim 2, characterized in that: The control point is a heater, the deformation controller is a temperature controller, and the heater generates heat when controlled by the temperature controller; or The control point is a discharger, and the discharger generates current when controlled by the deformation controller.

4. The polishing head according to claim 3, characterized in that: The shape compensation plate further includes a protective layer, which wraps the memory layer and the control points.

5. The polishing head according to any one of claims 2 to 4, characterized in that: When the polishing head grabs the wafer, the wafer is attached to the bottom surface of the shape compensation plate, and the memory layer is arranged close to the side of the shape compensation plate facing the wafer; The local deformation of the memory layer may force a corresponding position on the wafer to deform in a deformation direction substantially the same as the local deformation of the memory layer.

6. The polishing head according to any one of claims 1 to 4, characterized in that: The shape compensation plate has a vacuum adsorption portion or an electrostatic adsorption portion for adsorbing the wafer.

7. The polishing head according to any one of claims 1 to 4, characterized in that: The shape compensation plate is a two-way shape memory plate.

8. A polishing system, comprising a turntable and a polishing pad, wherein the polishing pad is mounted on the turntable, characterized in that: The polishing system also includes: The polishing head according to any one of claims 1 to 5; The deformation controller is electrically connected to the shape compensation plate; A detection unit, the detection unit is used to detect the flatness of the surface of the wafer grasped by the polishing head; A moving actuator, wherein the moving actuator can drive the polishing head and / or the detection unit to move; A rotary actuator can drive the polishing head and / or the polishing pad to rotate so that a side of the wafer away from the shape compensation plate contacts with the polishing pad for grinding.

9. The polishing system according to claim 8, characterized in that: The detection unit is a graphic sensor, a confocal sensor, a laser displacement sensor, a 3D laser profile sensor or a 3D vision sensor.

10. The polishing system according to claim 8 or 9, characterized in that: A first pressure chamber is provided between the main body of the polishing head and the retaining ring, and a second pressure chamber is provided between the main body and the backing film; The main body is provided with a first gas flow path, a second gas flow path and a third gas flow path. The first gas flow path is communicated with the first pressure chamber, and the second gas flow path is communicated with the second pressure chamber.

11. A control method for a polishing system, characterized in that: The polishing system is the polishing system according to any one of claims 8 to 10, and the control method comprises: Controlling the moving actuator to drive the polishing head and / or the detection unit to move relative to each other; Acquiring flatness data of the surface to be polished of the wafer grasped by the polishing head detected by the detection unit; According to the flatness data, at least one of the control points is controlled by the deformation controller to stimulate the shape compensation plate, so that the stimulated part of the shape compensation plate is deformed to adjust the flatness of the surface to be polished.

12. The control method according to claim 11, characterized in that: The step of obtaining the flatness data of the surface to be polished of the wafer caught by the polishing head detected by the detection unit comprises: The detection unit obtains height variation data from the surface to be polished to the detection unit and the wafer thickness variation data to confirm the concave position and concave depth of the surface to be polished.

13. The control method according to claim 11, characterized in that: The step of causing the stimulated part of the shape compensation plate to deform to adjust the flatness of the surface to be polished comprises: The control point stimulates the shape compensation plate to match the depth of the depression on the wafer, so that the shape compensation plate is deformed to match the degree of stimulation under the stimulation of the control point, and then pushes the depressed part of the wafer, forcing the corresponding position on the wafer to deform in a deformation direction that is basically the same as the local deformation of the shape compensation plate, so that the surface to be polished of the wafer remains flat as a whole.

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