Device and method for finishing surface flatness of double-sided grinding wheel

Abstract

The invention discloses a device and a method for finishing the surface flatness of a double-sided grinding wheel. The device comprises a circular finishing piece; the at least three supporting rollers are symmetrically arranged on the periphery of the finishing piece, and the central axes of the at least three supporting rollers are parallel to one another and are parallel to the central axis of the finishing piece; the supporting rollers can drive the finishing pieces to rotate around the central axes of the supporting rollers by rotating around the central axes of the supporting rollers in the same direction. The distance monitoring unit is used for monitoring the distance between the grinding wheel and the dressing piece in real time and sending out a monitoring signal when the grinding wheel is dressed to the preset position. When the device is used for finishing the surface of the grinding wheel, the surface of the grinding wheel is in contact with the surface of the finishing piece, and the supporting rollers simultaneously rotate in the same direction to drive the finishing piece to rotate around the central axis to finish the grinding wheel. According to the method, the abraded grinding wheel in continuous machining can be repaired, the grinding wheel is kept flat, and therefore the efficiency and quality of wafer production are guaranteed.

Description

Technical Field

[0001] The invention relates to a device and a method for finishing the surface flatness of a double-sided grinding wheel, belonging to the technical field of semiconductor wafer manufacturing. Background Art

[0002] With the development of science and technology, the use of smart devices is becoming more and more extensive, which has greatly promoted the development of the chip manufacturing industry and also put forward higher requirements for the surface quality of wafers. In order to manufacture wafers suitable for the current 4nm or even finer chip processing, the surface quality of the wafer is usually optimized through multiple process procedures such as rough grinding, fine grinding, corrosion, and polishing when manufacturing wafers. Among these processes, rough grinding is mainly responsible for removing the knife marks on the surface of the wafer, making the surface damage of the wafer uniform and consistent, and adjusting the thickness of the wafer, so that the thickness difference between the wafers is gradually reduced, and the surface flatness and parallelism are improved. For this reason, rough grinding is extremely important in the wafer manufacturing process. The current rough grinding method is mainly double-sided grinding. Double-sided grinding is a method of grinding by setting a pair of static pressure support plates on both sides of the wafer, so that the wafer is fixed in the middle of the static pressure support plate in a non-contact form, and the grinding wheels set on both sides of the wafer are fed to the wafer at the same time. Therefore, in the double-sided grinding process, the surface flatness of the grinding wheel plays a pivotal role in the quality of the wafer surface after rough grinding.

[0003] However, during the double-sided grinding process, since the wafer is fixed in the middle of the static pressure support plate in a non-contact manner, as the continuous processing proceeds, the wafer position may shift during the grinding process, causing the grinding wheel tooth shape to change during the grinding process. In addition, large knife marks or processing damage on the wafer surface before double-sided grinding will also cause the surface flatness of the grinding wheel to deteriorate after grinding. Therefore, during the double-sided grinding stage, maintaining the surface flatness of the grinding wheel is very important to ensure the efficiency and quality of wafer production.

[0004] Current double-sided grinding machines come with dressing devices, such as Figure 1 As shown in the figure, the conventional dressing device for grinding wheel W mainly consists of a cylindrical dressing device G that can rotate around the center and a supporting device S that supports the dressing device G below. When working, the dressing device G rotates around the center while the grinding wheels W on both sides slowly approach the dressing device G, thereby dressing the newly installed or damaged grinding teeth on the grinding wheel W, making the surface of the grinding teeth smooth and improving the grinding ability of the wafer.

[0005] However, on the one hand, the traditional dressing device is generally fixed on the equipment in an integrated manner. After long-term use, the dressing capacity is insufficient but it cannot be freely replaced, resulting in increased production costs. On the other hand, the traditional dressing device cannot cover the entire grinding tooth surface when dressing the grinding wheel, and the dressing efficiency is low; and excessive feeding of the grinding wheel will cause damage to the grinding tooth or even scrap. Summary of the invention

[0006] Based on the above background technology, the purpose of the present invention is to provide a device for dressing the surface flatness of a double-sided grinding wheel, by which the grinding wheel that is worn during continuous processing can be dressed so that the surface of the grinding wheel maintains good flatness, thereby ensuring the efficiency and quality of wafer production.

[0007] Another object of the present invention is to provide a method for performing surface flatness dressing of a double-sided grinding wheel using the device.

[0008] To achieve the above object, the present invention adopts the following technical solutions: A device for dressing the surface flatness of a double-sided grinding wheel, the device comprising: Round trimming piece, At least three supporting rollers are symmetrically arranged around the trimming sheet, and the central axes of the at least three supporting rollers are parallel to each other and to the central axis of the trimming sheet; the at least three supporting rollers drive the trimming sheet to rotate around its central axis by rotating in the same direction around their respective central axes; The distance monitoring unit is used to monitor the distance between the grinding wheel and the dressing disc in real time, and send out a monitoring signal when the grinding wheel dressing reaches a predetermined position.

[0009] Preferably, the trimming sheet is detachably mounted between at least three supporting rollers, and the number of the supporting rollers is preferably four.

[0010] Preferably, the trimming sheet is composed of a resin located at the center and corundum disposed on the periphery of the resin.

[0011] Preferably, the device further comprises a water spray cooling device for spraying pure water to the contact portion between the dressing sheet and the grinding wheel during the dressing operation to clean dust particles generated by friction and cool heat generated by friction.

[0012] A method for dressing the surface flatness of a double-sided grinding wheel, using the device to dress the surface of the grinding wheel, two grinding wheels are respectively mounted on a static pressure support disk and placed on the front and rear sides of a dressing sheet; support rollers rotate simultaneously and in the same direction around their respective central axes to drive the dressing sheet to rotate around its central axis, so that the surface of the grinding sand contacts the surface of the dressing sheet; and the feeding distance of the grinding wheel is controlled by a distance monitoring unit.

[0013] Beneficial effects of the present invention: The present invention provides a device and method for dressing the surface flatness of a double-sided grinding wheel, which is mainly aimed at dressing the rough, tilted surface of a new grinding wheel of a wafer grinding device and the wear of the grinding wheel surface caused by continuous processing. Compared with the traditional dressing device, the device of the present invention includes a distance sensor for monitoring the dressing position of the grinding wheel and a replaceable dressing sheet. The distance sensor enables the grinding wheel to move toward the dressing sheet within a fixed safety distance to dress the grinding wheel, thereby ensuring the uniformity of the dressing of the grinding wheel; if the dressing sheet is seriously consumed, the dressing sheet can be replaced according to the actual situation without changing the entire grinding device; dressing sheets with different dressing capabilities can also be used in sequence to dress the grinding wheel that needs to be dressed in a multiple progressive dressing manner, such as rough dressing first and then fine dressing, so that the quality of the product processed by the dressed grinding wheel is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of a traditional grinding wheel dressing device.

[0015] Figure 2 A front view of the front side of a device for dressing a grinding wheel provided in accordance with an embodiment of the present invention.

[0016] Figure 3 Schematic diagram of the structure of the trimming sheet used in the present invention.

[0017] Figure 4 for Figure 2 The device shown is a schematic structural diagram observed from the left side, with the static pressure support plate omitted in the figure.

[0018] Figure 5 for Figure 2 The schematic diagram of the structure of the device shown is used for grinding wheel dressing, in which the static pressure support plate is omitted. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Therefore, although this specification has described the present invention in detail with reference to the above embodiments, it should be understood by those skilled in the art that the present invention can still be modified or replaced by equivalents; and all technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

[0020] like Figure 2As shown, an embodiment of the present invention provides a device 100 for dressing grinding wheels, and the device 100 includes: four support rollers 101, the central axes of the four support rollers are parallel to each other; a pair of hydrostatic support discs B1 and B2 and grinding wheels W1 and W2 arranged on the sides of the hydrostatic support discs; at least one pair of distance monitoring units 102a, 102b for monitoring the feed of grinding wheels W1, W2; at least one pair of water spray cooling devices 103a, 103b; and a circular dressing sheet D detachably arranged in the middle of the four support rollers 101 (the four support rollers are symmetrically arranged around the dressing sheet D). Figure 3 As shown, the dressing sheet D is composed of a resin D2 located at the center and diamond sand D1 arranged on the periphery of the resin. The four supporting rollers 101 can rotate around their respective central axes at the same time and in the same direction to drive the dressing sheet D to rotate around its central axis to dress the grinding wheel W.

[0021] like Figure 4 As shown, four support rollers 101a, 101b, 101c, and 101d are on the same reference plane, and jointly drive the trimming sheet to rotate. It should be noted that the device 100 may include multiple support rollers on the same reference plane, such as 3, 5, etc. The trimming sheet D is placed in the center of the two static pressure support disks in a replaceable manner. The trimming sheet can be driven to rotate by the support rollers, and the surface of the trimming sheet D is made of 1000 mesh corundum. It should be noted that other types of corundum can be used on the surface of the trimming sheet D, such as 2000 mesh, 3000 mesh, etc. Figure 5 As shown, when the supporting roller drives the dressing piece to rotate, the grinding wheels W1 and W2 can be fed toward the dressing piece, and the ends of the grinding teeth T1 and T2 will contact the rotating dressing piece D. The surface flatness of the grinding wheel is trimmed by the mutual friction between the dressing piece D and the grinding teeth T1 and T2. The feed amount of the grinding wheel can also be monitored and controlled by the distance monitoring unit 102 to adjust the dressing amount of the grinding teeth T1 and T2.

[0022] The device for surface flatness dressing of double-sided grinding wheels provided by the embodiment of the present invention is different from the integrated structure of the traditional dressing device. The dressing sheet D provided by the present invention can be used multiple times and can be replaced at any time according to production needs without the need to dismantle and replace machine parts; different dressing methods can also be formulated according to different models of grinding wheels to improve the dressing efficiency. For example: when the grinding tooth loss is large, a 1000-mesh coarse-mesh dressing sheet can be used for rough dressing first, and then a 3000-mesh fine-mesh dressing sheet can be used for fine dressing, thereby improving the surface flatness of the grinding wheel and improving efficiency.

[0023] For conventional dressing devices, such as Figure 1As shown in the figure, since the dressing device is in a column shape, it cannot contact the entire plane of the grinding teeth T at the same time when dressing the grinding wheel, so it cannot dress all the grinding teeth on the grinding wheel at the same time, which will cause the dressed grinding teeth to be not in the same plane, affecting the processing of the product. In view of this problem, according to a preferred embodiment of the present invention, as Figure 4 As shown, while the grinding teeth are being trimmed, the dressing sheet will continuously rotate and rub, and the supporting roller ensures that the surface of the dressing sheet remains parallel to the surface of the grinding wheel. The dressing sheet will rub against all the grinding teeth at the same time during the rotation process, thereby ensuring the flatness of the grinding wheel surface after the grinding teeth are trimmed using this method.

[0024] In actual production, the degree of wear of the grinding teeth is different, so the degree of dressing required is also different. Figure 2 As shown, in actual dressing operation, the distance of feeding of the grinding wheel can be controlled by the distance monitoring unit; for grinding wheels with lower grinding tooth loss, a dressing piece with a lower surface mesh number is selected, so that the grinding wheel can feed and dress the grinding teeth at a higher speed for a short distance; for grinding wheels with higher grinding tooth loss, a dressing piece with a lower surface mesh number can be selected, so that the grinding wheel can feed and rub the dressing piece at a faster speed for a short distance, and rough dressing can be performed to eliminate major damage to the grinding tooth surface, and then a dressing piece with a higher surface mesh number can be selected to make the grinding wheel feed the dressing piece at a slower speed for a long distance, and fine dressing can be performed to make the grinding tooth surface smooth; thereby, the dressing efficiency can be significantly improved.

[0025] During the dressing process, the friction between the dressing disc and the grinding tooth will produce dust particles and release heat. These dust particles and the released heat will affect the dressing efficiency and dressing effect of the grinding tooth. In order to reduce dust and heat, Figure 2 As shown, the device also includes a water spray cooling device, which sprays pure water to the contact area between the dressing plate and the grinding tooth during the dressing operation to clean the dust particles generated by friction and cool the heat generated by friction.

Claims

1. A device for finishing the surface flatness of a double-sided grinding wheel, characterized in that: The device includes: Round trimming piece, At least three supporting rollers are symmetrically arranged around the trimming sheet, and the central axes of the at least three supporting rollers are parallel to each other and to the central axis of the trimming sheet; the at least three supporting rollers drive the trimming sheet to rotate around its central axis by rotating in the same direction around their respective central axes; The distance monitoring unit is used to monitor the distance between the grinding wheel and the dressing piece in real time, and send out a monitoring signal when the grinding wheel dressing reaches a predetermined position.

2. The device for surface flatness dressing of double-sided grinding wheels according to claim 1, characterized in that: The trimming sheet is detachably mounted between at least three supporting rollers.

3. The device for finishing the surface flatness of a double-sided grinding wheel according to claim 1 or 2, characterized in that: The number of the supporting rollers is four.

4. The device for finishing the surface flatness of a double-sided grinding wheel according to claim 1 or 2, characterized in that: The trimming sheet is composed of a resin located at the center and corundum disposed on the periphery of the resin.

5. The device for finishing the surface flatness of a double-sided grinding wheel according to claim 1 or 2, characterized in that: The device also includes a water spray cooling device, which sprays pure water to the contact part between the dressing piece and the grinding wheel during the dressing operation to clean the dust particles generated by friction and cool the heat generated by friction.

6. A method for finishing the surface flatness of a double-sided grinding wheel, characterized in that: The surface of a grinding wheel is dressed using the device described in any one of claims 1 to 5, wherein two grinding wheels are respectively mounted on a static pressure support disk and are placed on the front and rear sides of a dressing sheet; the supporting rollers rotate simultaneously and in the same direction around their respective central axes to drive the dressing sheet to rotate around its central axis so that the surface of the grinding sand contacts the surface of the dressing sheet; and the feeding distance of the grinding wheel is controlled by a distance monitoring unit.

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