Edge polishing head, wafer edge polishing device and wafer edge polishing method

Abstract

The invention provides an edge polishing head for wafer edge polishing, a wafer edge polishing device and a wafer edge polishing method. The wafer edge polishing device comprises a chuck rotating motor and a shell, the chuck rotating motor is fixed to the shell, and a vacuum chuck, an edge polishing head, an edge polishing head rotating motor, a polishing head shifting mechanism and a polishing solution supply device are arranged in the shell. The vacuum chuck is configured to rotate around the central axis of the vacuum chuck under the driving of the chuck rotating motor, the edge polishing head comprises a polishing wheel, an annular pad and abrasive paper, the polishing wheel has a circular cross section, the annular pad sleeves the periphery of the polishing wheel, the abrasive paper is attached to the periphery of the annular pad, the annular pad is made of an elastic material, and the abrasive paper is attached to the periphery of the annular pad. The polishing wheel is configured to be capable of rotating around the center axis of the polishing wheel under driving of the edge polishing head rotating motor.

Description

Technical Field

[0001] The present invention generally relates to the field of semiconductor manufacturing, and more particularly, to an edge polishing head, a wafer edge polishing apparatus, and a wafer edge polishing method. Background Art

[0002] As semiconductor technology develops towards larger wafers, higher requirements are placed on the surface granularity, edge and surface flatness of wafers. In the slicing process of preparing wafers, due to various reasons, such as uneven temperature during crystal growth or stress problems during slicing, the edges of the sliced ​​wafers are relatively rough, with unevenness, sharp corners and other defects. In subsequent processing, it may be affected by external forces. When the external force exceeds the maximum load of the wafer or the stress is overly concentrated, it will cause problems such as wafer cracks and wafer breakage, affecting the wafer process yield. Therefore, it is necessary to polish the edge of the wafer so that the damaged part of the wafer edge can be removed to obtain a smooth wafer edge.

[0003] Chemical mechanical polishing (CMP, also known as chemical mechanical planarization, chemical mechanical grinding) is a common technique used to achieve wafer surface planarization. This planarization method usually requires the substrate to be mounted on a carrier or polishing head. The exposed surface of the substrate is usually placed against a rotating polishing pad. A controllable load is provided on the substrate to abut against the polishing pad and push the substrate, and an abrasive polishing slurry is usually supplied to the surface of the polishing pad.

[0004] Chemical mechanical polishing equipment for edge polishing has been introduced into the wafer edge processing technology as a solution for wafer edge peeling or roughness cleaning. However, when using a separate edge polishing equipment, the installation and configuration of this independent polishing equipment not only requires a large capital investment and labor cost, but also increases the overall space of the equipment, and there are problems such as layout between process equipment and wafer transfer, which makes the operation cumbersome and inefficient.

[0005] In addition, wet etching or dry etching schemes used for the edge of the wafer will unnecessarily remove the film at the edge of the wafer. In addition, it will be limited by the film etching rate and the shape of the wafer edge is uneven, which seriously affects the process yield.

[0006] Public Content

[0007] In view of the above problems, the present invention provides an edge polishing head, a wafer edge polishing device and a wafer edge polishing method for wafer edge polishing, which are used to solve the problems of complex structure, low efficiency and high cost in related technologies.

[0008] According to a first aspect of the present invention, there is provided an edge polishing head for polishing the edge of a wafer, comprising: a polishing wheel, an annular pad and sandpaper, wherein the polishing wheel has a circular cross-section, an annular pad is sleeved on the outer periphery of the polishing wheel, sandpaper is attached to the outer periphery of the annular pad, and the annular pad is made of elastic material.

[0009] In the implementation of the first aspect of the present invention, the annular pad can be made of rubber material; the overall shape of the edge polishing head can be cylindrical or truncated cone; and the sandpaper can be flexible sandpaper.

[0010] According to a second aspect of the present invention, a wafer edge polishing device is provided, comprising: a chuck rotating motor and a shell, wherein the chuck rotating motor is fixed on the shell, and a vacuum chuck, an edge polishing head, an edge polishing head rotating motor, a polishing head shifting mechanism and a polishing liquid supply device are arranged in the shell, wherein the vacuum chuck is constructed to be able to rotate around the central axis of the vacuum chuck under the drive of the chuck rotating motor, wherein the edge polishing head comprises: a polishing wheel, an annular pad and sandpaper, wherein the polishing wheel has a circular cross-section, an annular pad is sleeved on the outer periphery of the polishing wheel, sandpaper is attached to the outer periphery of the annular pad, and the annular pad is made of elastic material, wherein the polishing wheel is constructed to be able to rotate around the central axis of the polishing wheel under the drive of the edge polishing head rotating motor.

[0011] In the implementation of the second aspect of the present invention, the overall shape of the edge polishing head can be a cylinder, or a truncated cone; the sandpaper can be flexible sandpaper.

[0012] In an embodiment of the second aspect of the present invention, the vacuum chuck may be oriented vertically.

[0013] In an embodiment of the second aspect of the present invention, the edge polishing head connected to the edge polishing head rotating motor may be detachable.

[0014] In an embodiment of the second aspect of the present invention, the polishing head shifting mechanism may include a movable robot arm and a robot arm motor.

[0015] In an embodiment of the second aspect of the present invention, a cleaning device is also included.

[0016] According to a third aspect of the present invention, a wafer edge polishing method is provided, using the wafer edge polishing device of the present invention, the method comprising the following steps:

[0017] Loading and holding a wafer to be processed on a vacuum chuck;

[0018] The edge polishing head is moved to a predetermined wafer edge polishing position by means of a polishing head shifting mechanism, so that the sandpaper of the edge polishing head is adjacent to the outer circumference of the wafer;

[0019] Driving the chuck rotation motor to make the vacuum chuck rotate around the central axis of the vacuum chuck under the drive of the chuck rotation motor, thereby driving the wafer to rotate along the first direction at a first speed;

[0020] driving the edge polishing head rotation motor to make the edge polishing head rotate at a second speed along a second direction;

[0021] controlling the torque of the polishing head rotation motor to adjust the force applied by the edge polishing head to the outer circumference of the wafer, thereby adjusting the depth to which the edge of the wafer is embedded from the outer circumference of the edge polishing head;

[0022] The polishing liquid is sprayed toward the outer circumference of the edge polishing head in contact with the edge of the wafer through the polishing liquid supply device, and the edge of the wafer is polished as the wafer and the edge polishing head rotate.

[0023] In an embodiment of the third aspect of the present invention, the wafer to be processed may be vertically loaded and held on a vacuum type chuck.

[0024] In an embodiment of the third aspect of the present invention, the edge polishing head may be a cylindrical polishing head.

[0025] In an embodiment of the third aspect of the present invention, when polishing the edge of the front side of the wafer, a first frustum-shaped polishing head can be used, the end face of the first frustum-shaped having a relatively large diameter on the front side of the wafer, and the end face of the first frustum-shaped having a relatively small diameter on the back side of the wafer; when polishing the edge of the back side of the wafer, a second frustum-shaped polishing head can be used, the end face of the second frustum-shaped having a relatively small diameter on the front side of the wafer, and the end face of the second frustum-shaped having a relatively large diameter on the back side of the wafer.

[0026] In the implementation of the third aspect of the present invention, the second turn may be the same as the first turn or may be different from the first turn, as long as the relative movement between the wafer and the edge polishing head can achieve edge grinding.

[0027] In an embodiment of the third aspect of the present invention, the first rotation speed may be about 50-1000 RMP, the second rotation speed may be about 500-20000 RMP, and the pressure applied may cause the outer periphery of the wafer to be embedded inwardly by a distance of about 0.1-2 mm relative to the edge polishing head.

[0028] As described above, the wafer edge polishing device and method of the present invention have the following beneficial effects: According to the present invention, the edge polishing head has a high resilience property, which is conducive to abutting the wafer edge for polishing, and it has a fast recovery ability, which helps to improve the polishing uniformity and is conducive to increasing the service life of the edge polishing head. According to the wafer edge polishing device of the present invention, a stable polishing operation of the wafer edge can be achieved.

[0029] The surface angle of the outer shape of the edge polishing head of the wafer edge polishing device according to the present invention can be modified, and the size and surface angle of the polishing head can be customized to meet the polishing needs of the front or back side of the wafer and different process requirements.

[0030] The wafer edge polishing device according to the present invention can be integrated and assembled into the cavity position of existing wafer polishing equipment such as chemical mechanical polishing equipment (such as CMP cleaner), such as the cleaning tank position, so as to add a new processing function module to the existing wafer polishing equipment, and it is beneficial to reduce the overall volume of the wafer polishing equipment, simplify the operation and save manpower and capital investment accordingly. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The following is a detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. The accompanying drawings are only exemplary and do not constitute a limitation on the present invention. In the accompanying drawings, the same reference numerals refer to the same elements, wherein:

[0032] Figure 1 The schematic diagram of the structure of the wafer edge polishing device according to the present invention is schematically shown, wherein (a) is an overall schematic diagram, and (b) is a partial schematic diagram;

[0033] Figure 2 A schematic cross-sectional view schematically showing an edge polishing head in a wafer edge polishing apparatus; and

[0034] Figure 3A , Figure 3B and Figure 3C Schematically illustrated are alternative shapes of edge polishing heads.

[0035] It should be understood that, for the sake of simplicity and / or clarity of illustration, the elements shown in the drawings are not necessarily drawn to scale. For example, for the sake of clarity, the sizes of some elements may be exaggerated relative to other elements. In addition, in order to make the concept of the present invention easier to understand, elements known in the art are omitted in the drawings. The sizes of the drawings do not represent the exact sizes and / or size ratios of the various elements described herein. DETAILED DESCRIPTION

[0036] Several specific details are set forth in the following description. However, the embodiments described herein can be implemented without certain specific details. In the detailed description, well-known structures and technologies are not shown in detail to avoid unclear understanding of the description.

[0037] It should be understood that the structures, proportions, sizes, etc. shown in the diagrams attached to this specification are only used to cooperate with the contents disclosed in the specification for understanding the present invention, and are not used to limit the conditions under which the present invention can be implemented. Without affecting the effects and purposes that can be achieved by the present invention, any structural modifications or changes, changes in proportional relationships, or adjustments in dimensions should fall within the scope of the technical contents disclosed by the present invention.

[0038] It should be understood that in the description of the present invention, the orientations or positional relationships indicated by the terms "one end", "the other end", "both ends", "one side", "middle", "upper", "top", "front", "bottom", "front", "back", "coaxial", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the described device or element must have a specific orientation or must be constructed and operated in a specific orientation. Therefore, it should not be interpreted as a limitation on the present invention. Changes or adjustments to their relative relationships should also be regarded as the scope of the present invention if there is no substantial change in the technical content.

[0039] It should be understood that the description of the position and orientation in the description of the present invention, such as "vertical", "vertically", "horizontally", "horizontally", is based on the position and orientation shown in the drawings, which is intended to describe the relative positional relationship between the elements, and should not be interpreted as vertical and / or horizontal in a strict sense, and is not limited to vertical and / or horizontal orientation. In addition, such terms do not indicate or imply that the device or element described must have the specific orientation or must be constructed and operated in the specific orientation, and therefore should not be interpreted as a limitation on the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantial changes in the technical content.

[0040] In the present invention, unless otherwise clearly stipulated and limited, the terms "install", "set", "load", "fix", "connect", "connected", "rotate", "turn" and the like should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection, or formed as one body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, those skilled in the art can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0041] It should be understood that ordinal numbers such as "first", "second", "third", etc. may be used herein to describe elements. Unless explicitly stated, they are only used to distinguish different elements and do not imply that the elements described must be in a given order in time, space, or other aspects.

[0042] In addition, it should also be understood that the word "about" or "approximately" may be used herein to modify a numerical value, which means within the normal tolerance range in this field. For example, "about" or "approximately" can be understood as within 1% of the modified numerical value.

[0043] The wafer edge polishing device is a device for processing semiconductor wafers (hereinafter referred to as "wafers"). It should be understood that the semiconductor wafer herein is a general term for the wafer-mounted silicon wafer in the chip manufacturing process. In the present invention, there is no particular limitation on the semiconductor wafer.

[0044] In the accompanying drawings, Figure 1 The structure diagram of the wafer edge polishing device of the present invention is schematically shown. Figure 1 As shown in (a) and (b), the wafer edge polishing device includes: a chuck rotating motor 1 and a shell 2, the chuck rotating motor 1 is fixed on the shell 2, and the following components are arranged in the shell 2: a vacuum chuck 3, an edge polishing head 5, an edge polishing head rotating motor 6, a polishing head shifting mechanism 7 and a polishing liquid supply device 11.

[0045] The vacuum chuck 3 can be driven by the chuck rotating motor 1 to rotate around the central axis of the chuck 3 , thereby driving the wafer 4 to be processed placed on the chuck to rotate.

[0046] In such Figure 1 In the wafer edge polishing device shown, the vacuum chuck 3 is oriented vertically, and accordingly the wafer 4 is vertically loaded on the vacuum chuck 3. The lateral space required for the wafer edge polishing device constructed in this way can be smaller, for example, its size specification can be designed to occupy only one cavity space of an existing large-scale polishing equipment, such as a cleaning slot, so that the wafer edge polishing device of the present invention can be installed on or matched with or integrated into an existing large-scale wafer polishing equipment and / or machine table, which can not only expand the edge polishing function of the existing polishing equipment, but also save space.

[0047] However, the present invention is not limited to Figure 1 As shown in the structure, those skilled in the art should understand that, according to different application scenarios, the wafer edge polishing device of the present invention can also be constructed so that the vacuum chuck 3 is set to other orientations, such as horizontal placement, and accordingly, the wafer 4 is horizontally loaded on the vacuum chuck 3, or it can also be constructed to be placed at other angles, as long as the wafer edge grinding can be achieved.

[0048] The housing 2 preferably includes a sealing cover plate for opening and closing the housing. The sealing cover plate is preferably a transparent plate so that the polishing operation can be observed.

[0049] Figure 2 A schematic cross-sectional view of an edge polishing head is shown schematically.

[0050] The edge polishing head 5 comprises a polishing wheel 8, an annular pad 9 and sandpaper 10. The polishing wheel 8 has a circular cross section. The polishing wheel 8 can be made of materials such as synthetic plastics, resins, etc. The polishing wheel 8 is connected to the edge polishing head rotating motor 6, so that the polishing wheel 8 can rotate around the central axis of the polishing wheel under the drive of the edge polishing head rotating motor 6.

[0051] An annular pad 9 is sleeved on the outer periphery of the polishing wheel 8. Sandpaper 10 is attached to the outer periphery of the annular pad 9. The polishing wheel 8, the annular pad 9 and the sandpaper are arranged in sequence from the inside to the outside to form an edge polishing head 5.

[0052] The sandpaper 10 can be made of sandpaper of various specifications according to the process requirements, preferably flexible sandpaper. As an example, the flexible sandpaper can be made of diamond abrasive polishing belt, CeO2 abrasive polishing belt, etc.

[0053] The annular pad 9 can be used as a soft substrate, and it is made of elastic material. The elasticity of the annular pad 9 allows it to deform under pressure, so that when the annular periphery of the edge polishing head 5 abuts against the edge of the wafer 4, under the action of pressure, the edge of the wafer can be embedded from the periphery of the polishing head 5 to a desired depth, thereby, the edge of the wafer can be polished by the sandpaper 10 through the relative movement between the polishing head 5 and the edge of the wafer 4. Moreover, since the edge polishing head of the present invention has a high resilience, the polishing head has a fast recovery ability, which can improve the polishing uniformity and help to increase the service life of the edge polishing head. Preferably, the annular pad 9 is made of rubber material.

[0054] The size and surface angle of the outer shape of the edge polishing head according to the present invention can be modified, and the size and surface angle of the polishing head can be customized as needed.

[0055] Figure 3A , Figure 3B and Figure 3C Schematically illustrates the optional shape of the edge polishing head. As shown in the figure, the overall shape of the edge polishing head can be a cylindrical shape (see Figure 3A ), or it may be in the shape of a truncated cone (see Figure 3B , Figure 3C ). The above shapes are optional shapes of the edge polishing head, and the overall shape of the edge polishing head is not limited thereto. The overall shape of the edge polishing head can be designed according to the processing requirements of the wafer.

[0056] As an example, the surface of the wafer 4 facing the vacuum chuck 3 is called the wafer backside, and the surface of the wafer opposite to the backside is called the frontside. When polishing the edge of the wafer, the edge polishing head 5 can be a cylindrical polishing head (see Figure 3A ). With this shape of polishing head, the edges of the front and back sides of the wafer can be polished uniformly. In addition, when the edge of the front side of the wafer needs to be polished according to process requirements, a first frustum-shaped polishing head is preferably used. In this case, for the first frustum-shaped polishing head 5, the end face of the first frustum-shaped head on the front side of the wafer is designed to have a relatively large diameter, and correspondingly, the end face of the first frustum-shaped head on the back side of the wafer is designed to have a relatively small diameter (see Figure 3B ). In addition, when it is necessary to polish the edge of the back side of the wafer according to the process requirements, it is preferred to use a second frustum-shaped polishing head. In this case, for the second frustum-shaped polishing head 5, the end face of the second frustum on the back side of the wafer has a relatively large diameter, and the end face on the front side of the wafer is designed to have a relatively small diameter (see Figure 3C ).

[0057] The edge polishing head 5 connected to the edge polishing head rotating motor 6 is detachable so that the used polishing head can be replaced as needed.

[0058] The polishing head shifting mechanism 7 may include a movable mechanical arm and a mechanical arm motor. One end of the movable mechanical arm is connected to the mechanical arm motor, and the other end is connected to the edge polishing head rotating motor 6. The movable mechanical arm can rotate and shift under the drive of the mechanical arm motor, thereby adjusting the orientation of the mechanical arm, and then adjusting the relative position between the edge polishing head 5 and the wafer 4 to meet different polishing requirements.

[0059] Preferably, the movable robotic arm is a retractable robotic arm, and the movable robotic arm can be retracted and extended under the drive of the robotic arm motor, thereby adjusting the length of the robotic arm.

[0060] The wafer edge polishing device also includes a polishing liquid supply device, which may specifically include a polishing liquid supply pipeline and a polishing liquid supply nozzle. The supply nozzle may be designed so that the spraying angle of the nozzle is adjustable. One end of the polishing liquid supply pipeline is connected to the polishing liquid source, and the other end is connected to the supply nozzle. An automatic control valve may be provided on the pipeline, and the automatic control valve may be connected to the controller. The polishing liquid supply nozzle is placed on one side of the chuck to supply polishing liquid to the wafer surface.

[0061] The polishing liquid can be selected as needed. As an example, the polishing liquid can be deionized water. In another example, the polishing liquid can be an alkaline suspension of silicon dioxide, for example.

[0062] During the polishing process, the wafer 4 is placed on the vacuum chuck 3 and rotates at a high speed driven by the chuck. The polishing liquid supply nozzle located on one side of the chuck supplies polishing liquid to the surface of the wafer 4. As the wafer 4 rotates, the polishing liquid diffuses to the edge of the wafer, and the edge of the wafer contacts the sandpaper to achieve edge polishing.

[0063] The polishing liquid supply device can also be used as a cleaning device. For example, when the polishing operation is finished, the cleaning liquid can be supplied through the polishing liquid supply device.

[0064] Alternatively, the wafer edge polishing device may further include a cleaning device. The cleaning device includes a nozzle and a cleaning pipeline, one end of the cleaning pipeline is connected to the cleaning source, and the other end is connected to the nozzle. A control valve may be provided on the cleaning pipeline, and the control valve may be connected to the controller. When the edge polishing operation is completed, the controller may control the control valve to open so as to spray the cleaning liquid to the chuck and the sandpaper through the nozzle.

[0065] By cleaning the chuck and sandpaper with a cleaning liquid, particles in the polishing liquid and particles generated after grinding can be prevented from accumulating on the sandpaper and chuck, causing damage to the sandpaper and contamination of the chuck, while also avoiding damage to the wafer. The cleaning liquid can be selected as needed. As an example, the cleaning liquid can be deionized water.

[0066] The wafer edge polishing apparatus may further include a recovery component to recover the cleaning liquid.

[0067] The controller in the wafer edge polishing device may be a PLC controller, but is not limited thereto. The controller may pre-store process parameters (recipes) of the edge polishing process, including polishing time, polishing liquid flow rate, chuck rotation speed, etc., but is not limited thereto. The controller controls the start and end of the edge polishing process according to the pre-stored parameters, and the controller may control the rotation speed of the chuck, the polishing liquid flow rate, etc. The controller may also control the cleaning device.

[0068] The wafer edge polishing device of the present invention can be used in conjunction with existing large-scale wafer polishing equipment and / or machines (such as chemical mechanical polishing (CMP) equipment and / or machines). Specifically, the wafer edge polishing device of the present invention can be installed on, matched with, or integrated into existing large-scale wafer polishing equipment and / or machines. The space required by the wafer edge polishing device of the present invention is relatively small, and its size can be designed to, for example, only occupy one cleaning slot of a large-scale polishing device, so that it can be installed on, matched with, or integrated into an existing polishing device, which can not only expand the edge polishing function of the existing polishing device, but also save space. Therefore, the wafer edge polishing device of the present invention can replace a separate wafer edge polishing device, thereby saving the overall volume of the wafer polishing device, and the operation of integrating and assembling the wafer edge polishing device of the present invention is simple, which can save manpower and reduce costs.

[0069] The other structures of the wafer edge polishing device of the present invention are basically the same as those in the prior art and are not described in detail for the purpose of brevity.

[0070] Below Figure 1 Taking the wafer edge polishing device shown in the figure as an example, a method for performing wafer edge polishing using the wafer edge polishing device of the present invention is described.

[0071] When edge polishing is performed using the wafer edge polishing apparatus, the wafer 4 to be processed is loaded and held on the vacuum chuck 3 .

[0072] The edge polishing head 5 is moved to a predetermined wafer edge polishing position by the polishing head shifting mechanism 7, so that the sandpaper 10 of the edge polishing head 5 is adjacent to the outer circumference of the wafer 4. Specifically, the movable mechanical arm under the control of the controller is driven by the mechanical arm motor to adjust its position according to the process requirements, thereby adjusting the position of the edge polishing head connected to the mechanical arm.

[0073] The chuck rotation motor 1 is driven to make the chuck 3 rotate at a high speed around the central axis of the chuck 3 under the drive of the chuck rotation motor 1 , thereby driving the wafer 4 to rotate at a first speed along a first direction.

[0074] While the chuck 3 and the wafer 4 loaded thereon are kept rotating in the first direction, the edge polishing head rotation motor 6 is driven to rotate the edge polishing head 5 at a second speed along the second direction. The second direction can be the same as the first direction, for example, both are clockwise or both are counterclockwise. The second direction can also be different from the first direction, as long as the relative movement between the wafer and the edge polishing head can achieve the grinding edge. The first speed and the second speed can be set according to actual needs, for example, the first speed can be about 50 to 1000 RMP, and the second speed can be about 500 to 20000 RMP.

[0075] The torque of the polishing head rotating motor 6 is controlled to adjust the force applied by the edge polishing head to the outer circumference of the wafer 4, so as to adjust the depth of the edge of the wafer 4 embedded from the outer circumference of the edge polishing head 5 according to actual needs, that is, to adjust the edge polishing distance. For example, the pressure is applied so that the distance of the outer circumference of the wafer embedded inward relative to the edge polishing head can be about 0.1 to 2 mm, such as about 1 mm. The specific embedding distance can be fed back and adjusted in real time through the motor torque to detect and optimize the state of the wafer edge polishing operation and the quality of the wafer edge polishing.

[0076] The polishing liquid is sprayed toward the outer circumference of the edge polishing head 5 in contact with the wafer edge by the polishing liquid supply device 11. As the wafer 4 and the edge polishing head 5 rotate, the polishing liquid spreads to the edge of the wafer to polish the wafer edge. The flow rate of the polishing liquid can be set according to actual needs.

[0077] The order of the above steps is only exemplary, and the order of the steps can be adjusted according to actual needs, or multiple steps can be performed simultaneously.

[0078] After the wafer edge polishing operation is completed, the wafer is removed, and then the chuck and edge polishing head can be cleaned by a cleaning device, thereby avoiding particle residue, avoiding damage to the polishing belt and contamination of the chuck, and improving the polishing yield.

[0079] According to the wafer edge polishing device of the present invention, a stable polishing operation on the wafer edge can be achieved. The edge polishing head has a high resilience property, which is conducive to abutting the wafer edge for polishing. It also has a fast recovery ability, which helps to improve the polishing uniformity and is conducive to increasing the service life of the edge polishing head.

[0080] The surface angle of the outer shape of the edge polishing head of the wafer edge polishing device according to the present invention can be modified, and the size and surface angle of the polishing head can be customized to meet the polishing needs of the front or back side of the wafer and different process requirements.

[0081] The wafer edge polishing device according to the present invention can be integrated into the cleaning tank of existing wafer polishing equipment, such as a CMP cleaner, so as to add a new processing function module to the existing wafer polishing equipment, and is beneficial to reducing the overall volume of the wafer polishing equipment, simplifying the operation and saving manpower and capital investment accordingly.

[0082] It should be understood that although the present invention is described with respect to specific embodiments, those skilled in the art may modify one or more features thereof after reading the specification without exceeding the spirit and scope of the present invention. Therefore, this specification is not intended to limit the present invention. On the contrary, the scope of the present invention is limited only by the attached claims and their equivalents.

Claims

1. An edge polishing head (5) for polishing an edge of a wafer, comprising: A polishing wheel (8), an annular pad (9) and sandpaper (10), wherein the polishing wheel (8) has a circular cross section, the annular pad (9) is sleeved on the outer periphery of the polishing wheel (8), the sandpaper (10) is attached to the outer periphery of the annular pad (9), and the annular pad (9) is made of elastic material.

2. The edge polishing head according to claim 1, characterized in that: The annular pad (9) is made of rubber material.

3. The edge polishing head according to claim 1, characterized in that: The overall shape of the edge polishing head (5) is a cylinder.

4. The edge polishing head according to claim 1, characterized in that: The overall appearance of the edge polishing head (5) is a truncated cone shape.

5. The edge polishing head according to claim 1, characterized in that: The sandpaper (10) is flexible sandpaper.

6. A wafer edge polishing device, comprising: A chuck rotating motor (1) and a housing (2), wherein the chuck rotating motor (1) is fixed to the housing (2), and a vacuum chuck (3), an edge polishing head (5), an edge polishing head rotating motor (6), a polishing head shifting mechanism (7) and a polishing liquid supply device (11) are arranged in the housing (2), and the vacuum chuck (3) is configured to be rotatable around the central axis of the vacuum chuck (3) under the drive of the chuck rotating motor (1). The edge polishing head (5) comprises: a polishing wheel (8), an annular pad (9) and sandpaper (10); the polishing wheel (8) has a circular cross section; the annular pad (9) is sleeved on the outer periphery of the polishing wheel (8); the sandpaper (10) is attached to the outer periphery of the annular pad (9); and the annular pad (9) is made of an elastic material. The polishing wheel (8) is configured to be rotatable around a central axis of the polishing wheel (8) under the drive of the edge polishing head rotating motor (6).

7. The wafer edge polishing device according to claim 6, characterized in that: The annular pad (9) is made of rubber material.

8. The wafer edge polishing device according to claim 6, characterized in that: The overall shape of the edge polishing head (5) is a cylinder.

9. The wafer edge polishing device according to claim 6, characterized in that: The overall appearance of the edge polishing head (5) is a truncated cone shape.

10. The wafer edge polishing device according to claim 6, characterized in that: The sandpaper (10) is flexible sandpaper.

11. The wafer edge polishing device according to claim 6, characterized in that: The vacuum chuck (3) is oriented vertically.

12. The wafer edge polishing device according to claim 6, characterized in that: The edge polishing head (5) connected to the edge polishing head rotating motor (6) is detachable.

13. The wafer edge polishing device according to claim 6, characterized in that: The polishing head shifting mechanism (7) comprises a movable mechanical arm and a mechanical arm motor.

14. The wafer edge polishing device according to claim 6, characterized in that: A cleaning device is also included.

15. A wafer edge polishing method, using the wafer edge polishing device according to any one of claims 6 to 14, the method comprising the following steps: Loading and holding a wafer to be processed on the vacuum chuck; The edge polishing head is moved to a predetermined wafer edge polishing position by the polishing head shifting mechanism, so that the sandpaper of the edge polishing head is adjacent to the outer circumference of the wafer; Driving the chuck rotation motor to make the vacuum chuck rotate around the central axis of the vacuum chuck under the drive of the chuck rotation motor, thereby driving the wafer to rotate along the first direction at a first speed; driving the edge polishing head rotation motor to make the edge polishing head rotate at a second speed along a second direction; controlling the torque of the polishing head rotation motor to adjust the force applied by the edge polishing head to the outer circumference of the wafer, thereby adjusting the depth to which the edge of the wafer is embedded from the outer circumference of the edge polishing head; The polishing liquid supply device sprays the polishing liquid toward the outer circumference of the edge polishing head in contact with the edge of the wafer, and the edge of the wafer is polished as the wafer and the edge polishing head rotate.

16. The wafer edge polishing method according to claim 15, characterized in that: The wafer to be processed is vertically loaded and held on the vacuum type chuck.

17. The wafer edge polishing method according to claim 15, characterized in that: The edge polishing head is a cylindrical polishing head.

18. The wafer edge polishing method according to claim 15, characterized in that: When polishing the edge of the front side of the wafer, a first frustum-shaped polishing head is used, wherein the end surface of the first frustum-shaped head on the front side of the wafer has a relatively large diameter, and the end surface of the first frustum-shaped head on the back side of the wafer has a relatively small diameter; When polishing the edge of the back side of the wafer, a second frustum-shaped polishing head is used, wherein the end face of the second frustum-shaped body on the front side of the wafer has a relatively small diameter, and the end face of the second frustum-shaped body on the back side of the wafer has a relatively large diameter.

19. The wafer edge polishing method according to claim 15, characterized in that: The second turn is the same as the first turn, or the second turn is different from the first turn.

20. The wafer edge polishing method according to any one of claims 15 to 19, characterized in that: The first rotation speed is about 50-1000 RMP, the second rotation speed is about 500-20000 RMP, and the pressure is applied so that the outer periphery of the wafer is embedded inwardly relative to the edge polishing head by a distance of about 0.1-2 mm.

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