Grinding pad cleaning method, grinding pad cleaning device and polishing equipment

Abstract

The invention provides a grinding pad cleaning method, a grinding pad cleaning device and polishing equipment, and belongs to the technical field of semiconductor manufacturing. The polishing pad cleaning device comprises an image acquisition unit used for acquiring a surface image of a polishing pad; the cleaning unit comprises a brush and a brush moving assembly, a cleaning high-pressure nozzle used for spraying cleaning liquid is arranged in the brush, and the brush moving assembly is used for moving the brush on one side of the surface of the grinding pad; and the control unit is connected with the image acquisition unit and the cleaning unit, and the control unit is used for acquiring the distribution state of a glazed area on the surface of the grinding pad based on the surface image of the grinding pad so as to control the moving state of the brush according to the distribution state of the glazed area on the surface of the grinding pad. The polishing pad can effectively remove a glazed layer on the polishing pad.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a grinding pad cleaning method, a grinding pad cleaning device and a polishing device. Background Art

[0002] Double-sided polishing equipment mainly cuts the wafer through the friction of the grinding pad (Pad) to control its flatness. During the double-sided grinding process, the flatness and surface defects of the wafer must be strictly controlled. Therefore, most grinding pads use soft materials, such as foaming materials and non-woven fabrics, which make their surfaces loose and porous. The porous structure has a good tolerance for silicate waste generated during the wafer processing process. After the silicate enters the pores of the Pad, a glazing layer (Glazzing) will be produced. Therefore, after each grinding process, the glazing layer must be rinsed by a high-pressure cleaning system (HPMJ). However, when the cleaning capacity is insufficient, the glazing layer cannot be completely removed, resulting in a glazing layer remaining after each grinding process. As the number of processes increases, the glazing gradually worsens, which will cause scratches and contamination to the wafer, affecting the yield and quality of the wafer. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a grinding pad cleaning method and a grinding pad cleaning device, and a polishing device, which can effectively remove the glaze layer on the grinding pad.

[0004] In order to achieve the above object, the technical solution adopted in the embodiment of the present invention is:

[0005] A grinding pad cleaning device, comprising:

[0006] An image acquisition unit, used for acquiring a surface image of the polishing pad;

[0007] A cleaning unit, comprising a brush and a brush moving assembly, wherein the brush is provided with a cleaning high-pressure nozzle for spraying a cleaning liquid, and the brush moving assembly is used to move the brush on one side of the surface of the polishing pad;

[0008] A control unit is connected to the image acquisition unit and the cleaning unit, and the control unit is used to obtain the distribution state of the glazing area on the surface of the grinding pad based on the surface image of the grinding pad, so as to control the movement state of the brush according to the distribution state of the glazing area on the surface of the grinding pad.

[0009] In some embodiments, the brush moving assembly includes:

[0010] A driving motor, wherein the driving motor is disposed outside the polishing pad, and an output shaft of the driving motor is arranged parallel to a rotation axis of the polishing pad; and

[0011] A swing arm, one end of which is connected to the output shaft of the driving motor, the brush is connected to the other end of the swing arm, and the brush moves on the surface of the polishing pad along the radial direction from the center of the polishing pad to the edge of the polishing pad under the drive of the swing arm;

[0012] Wherein, the control unit is connected to the driving motor, and the control unit is used to control the moving speed of the brush based on the control of the driving motor.

[0013] In some embodiments,

[0014] The polishing pad comprises an upper fixed plate and a lower fixed plate; the brush moves between the upper fixed plate and the lower fixed plate under the drive of the brush moving assembly.

[0015] In some embodiments, the control unit is specifically used to: obtain the distribution position of the glazing area; control the brush to move along a predetermined path on the surface of the polishing pad, and determine whether the brush is currently moved to the location of the glazing area; when the brush moves to the location of the glazing area, reduce the movement speed of the brush; when the brush moves to a position other than the glazing area, increase the movement speed of the brush.

[0016] In some embodiments, the brush is connected to the swing arm via a rotatable slip ring assembly.

[0017] In some embodiments, the rotation direction of the slip ring assembly is opposite to the rotation direction of the upper fixed plate and the lower fixed plate.

[0018] An embodiment of the present invention further provides a polishing device, comprising the polishing pad cleaning device as described above.

[0019] The embodiment of the present invention further provides a polishing pad cleaning method, which is applied to the polishing pad cleaning device as described above, and the method comprises the following steps:

[0020] collecting a surface image of the polishing pad;

[0021] Based on the surface image of the polishing pad, the distribution state of the glazing area on the surface of the polishing pad is acquired, so as to control the movement state of the brush according to the distribution state of the glazing area on the surface of the polishing pad.

[0022] In some embodiments, the step of obtaining the distribution state of the glazing area on the surface of the polishing pad to control the movement state of the brush according to the distribution state of the glazing area on the surface of the polishing pad comprises:

[0023] Obtain the distribution position of the glazing area; control the brush to move along a predetermined path on the surface of the polishing pad, and determine whether the brush is currently moved to the location of the glazing area; when the brush moves to the location of the glazing area, reduce the movement speed of the brush; when the brush moves to a location other than the glazing area, increase the movement speed of the brush.

[0024] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores at least one instruction, and the at least one instruction is used to be executed by a processor to implement the above-mentioned polishing pad cleaning method.

[0025] The beneficial effects of the present invention are:

[0026] In this embodiment, an image acquisition unit is provided in the grinding pad cleaning device, which can capture the surface image of the grinding pad during the grinding process. The control unit obtains the distribution state of the glazed area on the surface of the grinding pad, and controls the movement state of the brush according to the distribution state of the glazed area on the surface of the grinding pad. For example, its running speed in the glazed area is slowed down, and its running speed in the non-glazed area is increased. This can effectively improve the cleaning efficiency, enhance the cleaning ability of the glazed layer without increasing the cleaning time, and effectively remove the glazed layer on the grinding pad, thereby effectively avoiding the poor batch quality of wafer products caused by the introduction or difficulty in eliminating the glazed layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A front view showing a high pressure cleaning system;

[0028] Figure 2 A top view showing a high pressure cleaning system;

[0029] Figure 3 A schematic diagram showing the motion trajectory of the high pressure cleaning system when it is working;

[0030] Figure 4 A schematic diagram showing the position of the glaze layer of the grinding pad;

[0031] Figure 5 A schematic diagram showing the movement trajectory of a brush on a glaze layer in the related art;

[0032] Figure 6 A schematic diagram showing the movement trajectory of a brush on a glaze layer according to an embodiment of the present invention;

[0033] Figure 7 A schematic flow chart showing a method for cleaning a polishing pad according to an embodiment of the present invention.

[0034] Reference numerals

[0035] 1 Swing arm

[0036] 2 brushes

[0037] 3 High pressure nozzle

[0038] 4 Brush fastening device

[0039] 5 Outer pin ring

[0040] 6 Glaze layer

[0041] 7. Abrasive pad

[0042] 8 Inner ring DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0044] The existing HPMJ system includes a swing arm, a high-pressure nozzle, a brush, and a control system. When the grinding pad needs to be cleaned after grinding, the swing arm moves to the innermost inner pin ring of the main equipment fixed plate, and is controlled by the control system to move to the outermost side of the fixed plate at a certain speed. At the same time, the upper and lower fixed plates rotate in the same direction, and the high-pressure water flow sprayed by the high-pressure nozzle directly acts on the rotating upper and lower pads. The water column makes a continuous spiral circular motion on the pad. At the same time, the brush on the periphery of the high-pressure nozzle moves in a straight line with the swing arm, brushing off the impurities washed by physical action, and then cleaning the entire pad.

[0045] However, due to the different contact areas between the wafer and the Pad during the grinding process, the severity of the glazing in different areas of the Pad is also different. Under the existing HPMJ operating mode, high-pressure cleaning is difficult to remove the glaze layer in severely glazed areas, increasing the risk of product defects.

[0046] Figure 1 A front view showing a high pressure cleaning system in the related art, Figure 2 A top view of a high pressure cleaning system is shown, such as Figure 1 and Figure 2 As shown, the high-pressure cleaning system includes: a swing arm 1, a brush 2 fixed at one end of the swing arm 1, a high-pressure nozzle 3 set in the brush 2, and a brush fastening device 4. The cleaning method of the high-pressure cleaning system is that the swing arm 1 moves from the center of the Pad to the circumference under the operation of the control system, and the brush 2 is fixed on the swing arm 1, surrounding the periphery of the high-pressure nozzle 3, and moving synchronously with the swing arm 1. The motion trajectory of the high-pressure cleaning system when working is shown in FIG. Figure 3As shown, the brush 2 moves in a straight line with the swing arm 1, and moves radially from the center of the circle to the circumference relative to the pad. For the glazed layer, this action mode is not the direction of the maximum force, and the action direction of the brush on the glazed layer is also limited to the diameter direction of the pad, resulting in a decrease in the efficiency of physical removal of impurities, affecting the cleaning effect. In addition, the running speed of the swing arm 1 is uniform relative to the pad, which results in the brush staying in the slightly glazed area and the severely glazed area The time per unit time is the same, there is a disadvantage of over-cleaning the non-glazed area and under-cleaning the severely glazed area, which in turn affects the cleaning efficiency and processing waiting time.

[0047] The invention provides a grinding pad cleaning method, a grinding pad cleaning device and a polishing device, which can effectively remove the glaze layer on the grinding pad.

[0048] An embodiment of the present invention provides a polishing pad cleaning device, comprising:

[0049] An image acquisition unit, used for acquiring a surface image of the polishing pad;

[0050] A cleaning unit, comprising a brush and a brush moving assembly, wherein the brush is provided with a cleaning high-pressure nozzle for spraying a cleaning liquid, and the brush moving assembly is used to move the brush on one side of the surface of the polishing pad;

[0051] A control unit is connected to the image acquisition unit and the cleaning unit, and the control unit is used to obtain the distribution state of the glazing area on the surface of the grinding pad based on the surface image of the grinding pad, so as to control the movement state of the brush according to the distribution state of the glazing area on the surface of the grinding pad.

[0052] In this embodiment, an image acquisition unit is provided in the grinding pad cleaning device, which can capture the surface image of the grinding pad during the grinding process. The control unit obtains the distribution state of the glazed area on the surface of the grinding pad, and controls the movement state of the brush according to the distribution state of the glazed area on the surface of the grinding pad. For example, its running speed in the glazed area is slowed down, and its running speed in the non-glazed area is increased. This can effectively improve the cleaning efficiency, enhance the cleaning ability of the glazed layer without increasing the cleaning time, and effectively remove the glazed layer on the grinding pad, thereby effectively avoiding the poor batch quality of wafer products caused by the introduction or difficulty in eliminating the glazed layer.

[0053] In some embodiments, the brush moving assembly includes:

[0054] A driving motor, wherein the driving motor is disposed outside the polishing pad, and an output shaft of the driving motor is arranged parallel to a rotation axis of the polishing pad; and

[0055] A swing arm, one end of which is connected to the output shaft of the driving motor, the brush is connected to the other end of the swing arm, and the brush moves on the surface of the polishing pad along the radial direction from the center of the polishing pad to the edge of the polishing pad under the drive of the swing arm;

[0056] Wherein, the control unit is connected to the driving motor, and the control unit is used to control the moving speed of the brush based on the control of the driving motor.

[0057] In this embodiment, the moving speed of the brush can be controlled, such as slowing down its running speed in areas prone to glazing and increasing its running speed in areas without glazing, etc. This can effectively improve the cleaning efficiency, enhance the cleaning ability of the glaze layer without increasing the cleaning time, and effectively remove the glaze layer on the polishing pad, thereby effectively avoiding poor batch quality of wafer products caused by the introduction or difficulty in eliminating the glaze layer.

[0058] In some embodiments, the polishing pad includes an upper fixed plate and a lower fixed plate; the brush is driven by the brush moving assembly to move between the upper fixed plate and the lower fixed plate, and the brush is driven by the swing arm to move along the surface of the polishing pad in a radial direction from the center of the polishing pad to the edge of the polishing pad, thereby being able to clean the upper fixed plate and the lower fixed plate at the same time.

[0059] During the polishing process, the wafer has different contact areas and durations with the polishing pad. Figure 4 Schematic diagram showing the position of the polishing pad glaze layer 6, wherein 5 is an outer pin ring and 8 is an inner pin ring. Figure 4 As shown, there is an annular area on the grinding pad 7, the inner diameter of which is one-third of the radius of the grinding pad 7, and the outer diameter is two-thirds of the radius of the grinding pad 7. The contact time between the annular area and the wafer is the longest, and the contact area is the largest. Therefore, the degree of glaze layer 6 in the annular area is the most serious, and it is also the most difficult to be removed by high-pressure water flow and brush. In other areas of the grinding pad, there is basically no glaze layer 6. Therefore, this embodiment can intervene in the running trajectory of the swing arm, reduce the swing arm speed when the brush runs to the glaze-prone area, increase the high-pressure flushing time per unit time, and thus increase the cleaning rate. Correspondingly, no glaze occurs in the area that the wafer cannot contact during the grinding process, and the swing arm speed is increased when the brush runs to the area where no glaze occurs, thereby reducing the cleaning time and processing waiting time. In this way, by controlling the swing arm speed, the cleaning efficiency can be enhanced.

[0060] In some embodiments, the control unit is specifically used to: obtain the distribution position of the glazing area; control the brush to move along a predetermined path on the surface of the polishing pad, and determine whether the brush is currently moved to the location of the glazing area; when the brush moves to the location of the glazing area, reduce the movement speed of the brush; when the brush moves to a position other than the glazing area, increase the movement speed of the brush.

[0061] Figure 5 A schematic diagram showing the movement trajectory of a brush on the glaze layer 6 in the related art is shown. Figure 5 It can be seen that the existing brush moves linearly with the swing arm, and moves radially from the center of the circle to the circumference relative to the grinding pad. In this way, the glazed layer 6 can only be subjected to the radial force of the brush, and the glazed layer 6 cannot be effectively removed. In this embodiment, the brush is connected to the swing arm through a rotatable slip ring assembly, so that the brush can rotate while moving with the swing arm. In this way, when the brush moves radially from the center of the circle to the circumference, it can also apply a circumferential force to the glazed layer 6, thereby better removing the glazed layer 6.

[0062] In some embodiments, the rotation direction of the slip ring assembly may be opposite to the rotation direction of the upper and lower fixed plates, so that the contact time between the brush and the glaze layer 6 can be increased, thereby better cleaning the glaze layer 6. Figure 6 As shown, the brush can rotate while moving with the swing arm, and the rotation direction is opposite to the rotation direction of the upper and lower fixed plates. In this way, when the brush moves radially from the center of the circle to the circumference, it also applies a circumferential force to the glazed layer 6, thereby increasing the cleaning efficiency and better removing the glazed layer 6 without changing the flow rate and pressure of the high-pressure water flow.

[0063] The embodiment of the present invention further provides a polishing device, including the above-mentioned grinding pad cleaning device. Obviously, the polishing device provided by the embodiment of the present disclosure also has the beneficial effects brought by the grinding pad cleaning device provided by the embodiment of the present disclosure, which will not be described in detail here.

[0064] The embodiment of the present invention further provides a polishing pad cleaning method, which is applied to the polishing pad cleaning device as described above. Figure 7 As shown, the method comprises the following steps:

[0065] Step 101: collecting a surface image of the polishing pad;

[0066] Step 102: Based on the surface image of the polishing pad, the distribution state of the glazing area on the surface of the polishing pad is obtained, so as to control the movement state of the brush according to the distribution state of the glazing area on the surface of the polishing pad.

[0067] In this embodiment, the surface image of the grinding pad is collected during the grinding process, the distribution state of the glazed area on the surface of the grinding pad is obtained, and the movement state of the brush is controlled according to the distribution state of the glazed area on the surface of the grinding pad, such as slowing down its running speed in the glazed area frequently, and increasing its running speed in the non-glazed area, etc. This can effectively improve the cleaning efficiency, enhance the cleaning ability of the glazed layer without increasing the cleaning time, and effectively remove the glazed layer on the grinding pad, thereby effectively avoiding the batch defects of wafer products caused by the introduction or difficulty in eliminating the glazed layer.

[0068] In some embodiments, the step of obtaining the distribution state of the glazing area on the surface of the polishing pad to control the movement state of the brush according to the distribution state of the glazing area on the surface of the polishing pad comprises:

[0069] Obtain the distribution position of the glazing area; control the brush to move along a predetermined path on the surface of the polishing pad, and determine whether the brush is currently moved to the location of the glazing area; when the brush moves to the location of the glazing area, reduce the movement speed of the brush; when the brush moves to a location other than the glazing area, increase the movement speed of the brush.

[0070] During the polishing process, the wafer has different contact areas and durations with the polishing pad. Figure 4 Schematic diagram showing the position of the polishing pad glaze layer 6, wherein 5 is an outer pin ring and 8 is an inner pin ring. Figure 4 As shown, there is an annular area on the grinding pad 7, the inner diameter of which is one-third of the radius of the grinding pad 7, and the outer diameter is two-thirds of the radius of the grinding pad 7. The contact time between the annular area and the wafer is the longest, and the contact area is the largest. Therefore, the degree of glaze layer 6 in the annular area is the most serious, and it is also the most difficult to be removed by high-pressure water flow and brush. In other areas of the grinding pad, there is basically no glaze layer 6. Therefore, this embodiment can intervene in the running trajectory of the swing arm, reduce the swing arm speed when the brush runs to the glaze-prone area, increase the high-pressure flushing time per unit time, and thus increase the cleaning rate. Correspondingly, no glaze occurs in the area that the wafer cannot contact during the grinding process, and the swing arm speed is increased when the brush runs to the area where no glaze occurs, thereby reducing the cleaning time and processing waiting time. In this way, by controlling the swing arm speed, the cleaning efficiency can be enhanced.

[0071] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores at least one instruction, and the at least one instruction is used to be executed by a processor to implement the above-mentioned polishing pad cleaning method.

[0072] Those skilled in the art should be aware that in one or more of the above examples, the functions described in the embodiments of the present application can be implemented with hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein the communication media include any media that facilitates the transmission of a computer program from one place to another. The storage medium can be any available medium that a general or special-purpose computer can access.

[0073] It should be noted that each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the embodiments, since they are basically similar to the product embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the product embodiments.

[0074] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0075] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A polishing pad cleaning device, characterized in that: include: An image acquisition unit, used for acquiring a surface image of the polishing pad; A cleaning unit, comprising a brush and a brush moving assembly, wherein the brush is provided with a cleaning high-pressure nozzle for spraying a cleaning liquid, and the brush moving assembly is used to move the brush on one side of the surface of the polishing pad; A control unit is connected to the image acquisition unit and the cleaning unit, and the control unit is used to obtain the distribution state of the glazing area on the surface of the grinding pad based on the surface image of the grinding pad, so as to control the movement state of the brush according to the distribution state of the glazing area on the surface of the grinding pad.

2. The polishing pad cleaning device according to claim 1, characterized in that: The brush moving assembly comprises: A driving motor, wherein the driving motor is disposed outside the polishing pad, and an output shaft of the driving motor is arranged parallel to a rotation axis of the polishing pad; and A swing arm, one end of which is connected to the output shaft of the driving motor, the brush is connected to the other end of the swing arm, and the brush moves on the surface of the polishing pad along the radial direction from the center of the polishing pad to the edge of the polishing pad under the drive of the swing arm; Wherein, the control unit is connected to the driving motor, and the control unit is used to control the moving speed of the brush based on the control of the driving motor.

3. The polishing pad cleaning device according to claim 1, characterized in that: The polishing pad comprises an upper fixed plate and a lower fixed plate; the brush moves between the upper fixed plate and the lower fixed plate under the drive of the brush moving assembly.

4. The polishing pad cleaning device according to claim 1, characterized in that: The control unit is specifically used to: obtain the distribution position of the glazing area; control the brush to move along a predetermined path on the surface of the polishing pad, and determine whether the brush is currently moved to the location of the glazing area; when the brush moves to the location of the glazing area, reduce the movement speed of the brush; when the brush moves to a location other than the glazing area, increase the movement speed of the brush.

5. The polishing pad cleaning device according to claim 3, characterized in that: The brush is connected to the swing arm via a rotatable slip ring assembly.

6. The polishing pad cleaning device according to claim 5, characterized in that: The rotation direction of the slip ring assembly is opposite to the rotation direction of the upper fixed plate and the lower fixed plate.

7. A polishing device, characterized in that: It comprises the polishing pad cleaning device as described in any one of claims 1 to 6.

8. A method for cleaning a polishing pad, characterized in that: Applied to the polishing pad cleaning device according to any one of claims 1 to 6, the method comprises the following steps: collecting a surface image of the polishing pad; Based on the surface image of the polishing pad, the distribution state of the glazing area on the surface of the polishing pad is acquired, so as to control the movement state of the brush according to the distribution state of the glazing area on the surface of the polishing pad.

9. The polishing pad cleaning method according to claim 8, characterized in that: The step of obtaining the distribution state of the glazing area on the surface of the polishing pad to control the movement state of the brush according to the distribution state of the glazing area on the surface of the polishing pad includes: Obtain the distribution position of the glazing area; control the brush to move along a predetermined path on the surface of the polishing pad, and determine whether the brush is currently moved to the location of the glazing area; when the brush moves to the location of the glazing area, reduce the movement speed of the brush; when the brush moves to a location other than the glazing area, increase the movement speed of the brush.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one instruction, and the at least one instruction is used to be executed by a processor to implement the polishing pad cleaning method according to any one of claims 8 to 9.

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