Grinding wheel self-sharpening enhancement method and device and wafer thinning equipment

Abstract

The invention relates to the technical field of semiconductor wafer processing, and provides a grinding wheel self-sharpening enhancement method and device and wafer thinning equipment. The method comprises the following steps of: determining a main washing position: judging whether the grinding wheel is subjected to outer edge processing or not based on the position of a grinding line of a grinding wheel grinding wafer and the rotating direction of the wafer, if so, determining the main washing position to be the outer side of the grinding wheel, and otherwise, determining the main washing position to be the inner side of the grinding wheel; the liquid spraying pressure and the swing frequency of the flusher at the main flushing position are set to be larger than the liquid spraying pressure and the swing frequency of the flusher on the opposite side; determining the flushing direction of the flusher based on the adhesion state of the abrasive particles forming the abrasive wheel and the adhesion state of the pollutants on the abrasive wheel; and based on the ratio of the feeding speed of the grinding wheel to the set feeding speed in the grinding process, the liquid spraying pressure and the swing frequency of the flusher are adjusted. According to the grinding wheel, the self-sharpening performance of the grinding wheel can be effectively enhanced, meanwhile, protection is provided for the grinding teeth, and the wafer thinning quality and efficiency are improved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor wafer processing, and specifically relates to a method and device for enhancing the self-sharpening of a grinding wheel and a wafer thinning device. Background Art

[0002] Generally, before integrated circuit packaging, it is necessary to remove a certain thickness of the redundant substrate material on the back side of the wafer. This technological process is called the wafer back thinning process, and the corresponding equipment is the wafer thinning device. With the development and progress of advanced packaging technologies, the product structures to be dealt with in the thinning stage tend to be more complex, evolving from the processing of wafers of a single material to the processing of wafers of composite materials. When a grinding wheel processes a wafer of composite material, due to the simultaneous presence of heterogeneous materials such as epoxy resin material, metal material, silicon, and glue, the adhesion of the grinding debris is relatively complex. The debris will adhere to the side wall or the bottom of the grinding teeth of the grinding wheel as the grinding wheel rotates, causing the grinding wheel to become blunt and lacking self-sharpening, which affects the grinding and thinning effect and the product quality. In the prior art, the self-sharpening of the grinding wheel is mainly achieved by replacing the grinding wheel or adjusting the processing parameters, but these methods are inefficient, costly, and difficult to meet the requirements of high-precision processing. Summary of the Invention

[0003] The present application provides a method and device for enhancing the self-sharpening of a grinding wheel and a wafer thinning device to solve or alleviate at least some of the problems mentioned above.

[0004] According to one aspect of the present application, there is provided a method for enhancing the self-sharpening of a grinding wheel, where the grinding wheel is used for grinding a wafer in a wafer thinning device, and flushing devices are respectively provided on the inner side, outer side, and bottom of the grinding wheel, and the flushing devices spray a cleaning liquid onto the grinding wheel. The method includes: Determining the main flushing position: Based on the position of the grinding line where the grinding wheel grinds the wafer and the rotation direction of the wafer, determining whether the grinding wheel is performing outer-edge processing. If so, the main flushing position is the outer side of the grinding wheel; otherwise, the main flushing position is the inner side of the grinding wheel; Setting the liquid spraying pressure and the swing frequency of the flushing device at the main flushing position to be respectively greater than those of the flushing device on the opposite side; Determining the flushing direction of the flushing device based on the adhesion state of the abrasive grains forming the grinding wheel and the adhesion state of the contaminants on the grinding wheel; Adjusting the liquid spraying pressure and the swing frequency of the flushing device based on the ratio of the feed speed of the grinding wheel during the grinding process to the set feed speed.

[0005] Optionally, the method further includes: as the rotation speed of the grinding wheel increases, increasing the liquid spraying pressure and the swing frequency of the flushing devices on the inner side, outer side, and bottom to reduce the dispersion effect of the air layer around the grinding wheel caused by the rotation of the grinding wheel on the cleaning liquid, and the increase in the liquid spraying pressure and the swing frequency of the flushing devices on the inner side and outer side is greater than the increase in the liquid spraying pressure and the swing frequency of the flushing device on the bottom.

[0006] Optionally, the grinding line extends from the center of the wafer to the edge of the wafer; determining whether the grinding wheel is performing outer-edge machining based on the position of the grinding line where the grinding wheel grinds the wafer and the rotation direction of the wafer includes: when the rotation direction of the part of the wafer located outside the grinding wheel faces the grinding line, it is determined as outer-edge machining; when the rotation direction of the part of the wafer located outside the grinding wheel deviates from the grinding line, it is determined as inner-edge machining.

[0007] Optionally, determining the flushing direction of the flushing device based on the adhesion state of the abrasive grains forming the grinding wheel and the adhesion state of contaminants on the grinding wheel includes: Setting the initial direction of the flushing device so that the component of its direction along the tangential direction of the grinding wheel is in the same direction as the tangential velocity of the grinding wheel, gradually increasing the liquid spraying pressure from the initial value to the maximum value. If the feed rate of the grinding wheel gradually increases from being lower than the set feed rate to being consistent with the set feed rate and the wear amount of the grinding wheel exceeds the wear amount range, it is determined that the adhesion state of the abrasive grains is easy to fall off, and the component of the flushing direction along the tangential direction of the grinding wheel is kept in the same direction as the tangential velocity of the grinding wheel; if the feed rate of the grinding wheel is always lower than the set feed rate and the wear amount of the grinding wheel is within the wear amount range, it is determined that the adhesion state of the abrasive grains is not easy to fall off and the adhesion state of the contaminants is not easy to fall off, and the flushing direction of the flushing device is set such that the component of the flushing direction along the tangential direction of the grinding wheel is in the opposite direction to the tangential velocity of the grinding wheel.

[0008] Optionally, the method further includes: when the adhesion state of the abrasive grains is not easy to fall off and the adhesion state of the contaminants is not easy to fall off, increasing the liquid spraying pressure and the swing frequency of the flushing device on the bottom so that the liquid spraying pressure and the swing frequency of the flushing device on the bottom are respectively equal to or slightly greater than the liquid spraying pressure and the swing frequency of the flushing device at the main flushing position.

[0009] Optionally, the method further includes: when the flushing direction of the flushing device is set such that the component of the flushing direction along the tangential direction of the grinding wheel is in the opposite direction to the tangential velocity of the grinding wheel, gradually increasing the liquid spraying pressure from the initial value to the maximum value. If the feed rate of the grinding wheel is always lower than the set feed rate and the wear amount of the grinding wheel is within the wear amount range, then the dresser with diamond particles on the top is abutted against the bottom of the grinding wheel for grinding and dressing.

[0010] Optionally, adjusting the liquid spraying pressure and the swing frequency of the flusher based on the ratio of the feed speed of the grinding wheel to the set feed speed during the grinding process includes: when the ratio of the feed speed of the grinding wheel to the set feed speed is lower than the set range, increasing the liquid spraying pressure and the swing frequency of the flusher; when the ratio of the feed speed of the grinding wheel to the set feed speed exceeds the set range, decreasing the liquid spraying pressure and the swing frequency of the flusher; the set range is from 0.9 to 1.1.

[0011] Optionally, the method further includes: when the adhesion state of the abrasive grains is not easy to fall off and the adhesion state of the contaminants is not easy to fall off, increasing the liquid spraying pressure and the swing frequency of the flusher at the bottom.

[0012] Optionally, the method further includes: adjusting the liquid spraying pressure and the swing frequency of the flusher based on the ratio of the machining currents of the motor driving the grinding wheel in two consecutive time periods.

[0013] Optionally, adjusting the liquid spraying pressure and the swing frequency of the flusher based on the ratio of the machining currents of the motor driving the grinding wheel in two consecutive time periods includes: when the ratio of the machining currents in two consecutive time periods exceeds the reference range, increasing the liquid spraying pressure and the swing frequency; when the ratio of the machining currents in two consecutive time periods is lower than the reference range, decreasing the liquid spraying pressure and the swing frequency; the lower limit value of the reference range is 1, and the upper limit value is the ratio of the maximum current of the motor driving the grinding wheel to the instantaneous current during 3 seconds of grinding.

[0014] Optionally, the flusher is configured with an ultrasonic generator, and the ultrasonic generator is used to generate ultrasonic vibrations in the cleaning liquid.

[0015] Optionally, two groups of flushers are respectively arranged on both sides of the central connection line of the wafer and the grinding wheel, and each group of flushers respectively includes the flushers located inside, outside and at the bottom of the grinding wheel. The method further includes: according to the rotation direction of the grinding wheel, turning on a group of flushers downstream of the wafer along the rotation direction of the grinding wheel.

[0016] According to another aspect of the present application, there is provided a device for enhancing the self-sharpening of a grinding wheel, which is used to execute the method for enhancing the self-sharpening of the grinding wheel described in the foregoing aspect, and includes: Three flushers respectively located inside, outside and at the bottom of the grinding wheel, and the flusher has a swingable nozzle to swingably spray the cleaning liquid onto the grinding wheel; A controller, the controller is electrically connected to the three flushers respectively, and is used to control one or more parameters among the opening and closing, liquid spraying pressure, flushing direction and swing frequency of the three flushers.

[0017] Optionally, the rinser further includes an ultrasonic generator, which causes the cleaning liquid to generate ultrasonic vibrations to assist in removing contaminants on the grinding wheel.

[0018] According to another aspect of the present application, there is provided a wafer thinning device, including: A carrier stage for adsorbing a wafer and driving the wafer to rotate; A grinding device, including a grinding wheel, which is used for grinding the wafer; A grinding wheel self-sharpening enhancement device as described in the foregoing aspect.

[0019] According to the grinding wheel self-sharpening enhancement method, device and wafer thinning device of the present application, especially when the wafer is composed of a composite material, the adhesion characteristics of the abrasive grains of the grinding wheel and the complexity and adhesion characteristics of the contaminants are fully considered. According to the processing conditions of the grinding wheel and the change trend of the processing parameters, the main adhesion positions of the contaminants and the adhesion characteristics of the abrasive grains and the contaminants are determined. Furthermore, the setting and adjustment methods of the rinsing parameters such as the main rinsing position, rinsing direction, liquid spraying pressure and swing frequency of the rinser are determined. Thus, by means of rinsing, while performing targeted rinsing on the grinding wheel, the self-sharpening of the grinding wheel is effectively improved, and effective protection is provided for the grinding teeth, avoiding damage to the grinding teeth during rinsing, ensuring the service life of the grinding wheel, reducing the replacement frequency of the grinding wheel, and improving the grinding and thinning quality and grinding efficiency of the grinding wheel for the wafer. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0021] Figure 1 A wafer thinning device provided by an embodiment of the present invention is shown in a schematic perspective view; Figure 2 Shows Figure 1 A schematic diagram of the grinding wheel grinding the wafer in Figure 3 Shows Figure 2 A top view of the grinding wheel and the wafer in , where only the grinding teeth on the grinding wheel are shown; Figure 4 Shows Figure 2 A schematic diagram of the contact state between the grinding wheel and the wafer in ; Figure 5 Shows Figure 2 Another schematic diagram of the contact state between the grinding wheel and the wafer in ; Figure 6 ShowsFigure 2 Microscopic schematic diagram of the grinding teeth of the grinding wheel in Figure 7 Schematic diagram showing a grinding wheel self-sharpening enhancement device according to an embodiment of the present application; Figure 8 Showing Figure 7 Flushing schematic diagram of the flusher on the side of the grinding wheel in Figure 9 Showing Figure 7 Flushing schematic diagram of the flusher at the bottom of the grinding wheel in Figure 10 Showing the bottom view of the grinding teeth and the side flusher; Figure 11 Showing the side view of the grinding teeth and the bottom flusher; Figure 12 Showing the bottom view of the grinding teeth and the side flusher at another inclination angle; Figure 13 Showing the side view of the grinding teeth and the bottom flusher at another inclination angle; Figure 14 Showing Figure 2 Schematic diagram of the dresser shown in Figure 15 Flow chart showing a grinding wheel self-sharpening enhancement method according to an embodiment of the present application.

[0022] Reference numerals: Workbench 31; Carrying table 32; Grinding device 2; Grinding wheel 100; Rough grinding part 21; Fine grinding part 22; Cleaning unit 5; Simple manipulator 6; Base 110; Grinding teeth 120; Abrasive grains 121; Air holes 122; Binder 123; Contaminants 124; Flusher 200; Nozzle 210; Cleaning liquid 211; Ultrasonic generator 220; Dresser 300; Dressing head 310; Diamond particles 311; Dressing seat 320; Wafer W; Grinding line L. Detailed implementation manners

[0023] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art shall fall within the protection scope of the embodiments of the present application.

[0024] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application.

[0025] In addition, in the description of the present application, unless otherwise specified and limited, it should be noted that the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the communication inside two elements. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0026] Figure 1 A wafer thinning device provided by an embodiment of the present application is schematically shown in a three-dimensional view and includes: A workbench 31 that supports a plurality of carrier tables 32. The carrier tables 32 adsorb and hold the wafer W and can drive the wafer W to rotate. The workbench 31 can rotate around its vertical central axis so that the workbench 31 drives the plurality of carrier tables 32 to rotate and move as a whole, thereby realizing the position conversion of the carrier tables 32 between different stations. Each carrier table 32 can also rotate independently; A grinding device 2 that includes a grinding wheel 100. The grinding wheel 100 is brought into contact with the wafer W to perform grinding and thinning treatment on the wafer W. The grinding wheel 100 is connected to a spindle assembly, and the spindle assembly has an inclination mechanism to adjust the inclination angle of the spindle in the front, rear, left, and right directions.

[0027] As Figure 1As shown, as an implementable mode, three separately rotatable carrier tables 32 are evenly distributed on the workbench 31, each having a first suction cup, a second suction cup, and a third suction cup for adsorbing the wafer W. The three suction cups can be porous ceramic suction cups with exactly the same structure to achieve vacuum adsorption of the wafer W. Moreover, the connecting lines between the centers of the three carrier tables 32 and the center of the workbench 31 form an angle of 120° with each other. The three carrier tables 32 correspond to three stations, namely the rough grinding station, the fine grinding station, and the loading and unloading station. Among them, the two stations opposite to the grinding wheel 100 are respectively used for rough grinding and fine grinding, and the remaining one station is used for loading, unloading, and cleaning of the wafer W. By rotating the workbench 31, the three carrier tables 32 can be driven to switch between these three stations, so as to realize the cyclic movement of the carrier table 32 carrying the wafer W in the order of loading and unloading station - rough grinding station - fine grinding station - loading and unloading station. In this embodiment, the full-automatic loading and unloading of the wafer W and continuous grinding and cleaning are realized through repeated cycles. Using the rotary workbench 31 for grinding the wafer W has the advantages of high material removal rate, small surface damage to the wafer W, and easy realization of automation.

[0028] The grinding device 2 is mainly composed of a rough grinding part 21 and a fine grinding part 22. The grinding wheel 100 at the rough grinding part 21 is used for rough grinding the wafer W, and the grinding wheel 100 at the fine grinding part 22 is used for fine grinding the wafer W. The grinding process is to press the grinding wheel 100 for grinding on the surface of the wafer W and rotate it to grind off a certain thickness.

[0029] Also as Figure 1 shown, the wafer thinning equipment further includes a cleaning unit 5, and the cleaning unit 5 is used for cleaning the suction cup and the wafer W. The wafer thinning equipment further includes a simple manipulator 6, and the simple manipulator 6 is used for placing the wafer W on the carrier table 32 for grinding, and taking out the wafer W from the carrier table 32 after grinding and cleaning for subsequent transfer. As an implementable mode, a pipeline for vacuum pumping is provided inside the simple manipulator 6 to realize vacuum adsorption of the wafer W.

[0030] Figure 2 shows Figure 1 a schematic diagram of the grinding wheel 100 grinding the wafer W in []. It can be seen that the grinding wheel 100 includes a base 110 and grinding teeth 120 provided on the base 110. The grinding wheel 100 is pressed on the wafer W and rotates and feeds axially at a certain feed rate to grind the wafer W. Figure 3 shows Figure 2 a top view of [], in which only the grinding teeth 120 on the grinding wheel 100 are shown, and the grinding teeth 120 are evenly spaced along the circumference. Figure 4 , Figure 5 shows Figure 2 a schematic diagram of the contact state between the grinding wheel 100 and the wafer W in []. During the rotary grinding process, when the grinding wheel 100 cuts into the wafer W, an arc-shaped contact action area will be generated, as Figure 4The solid black arc therein can be called the grinding line L. The grinding wheel 100 and the wafer W can adopt a semi-contact grinding method, that is, the grinding line L is only a part of the arc where the grinding wheel 100 and the wafer W overlap, about half, thereby reducing the grinding force and grinding heat during the grinding process of the wafer W and improving the grinding surface quality of the wafer W.

[0031] Figure 6 The microscopic schematic diagram of the grinding teeth 120 of the grinding wheel 100 is shown. The grinding teeth 120 are formed on the base 110 by mixing abrasive grains 121 with materials such as binder 123 and pore-forming agent and through sintering, electroplating or resin curing processes. The black dots in the figure represent the abrasive grains 121, the white ellipses represent the formed pores 122, the gray irregular shapes surrounding the abrasive grains 121 represent the binder 123, and the white cloud-like shapes are contaminants 124. The abrasive grains 121 are horizontally and vertically bonded through the binder 123. Here, the horizontal direction refers to parallel to the lower surface of the base 110, and the vertical direction refers to perpendicular to the lower surface of the base 110.

[0032] With the development and progress of advanced packaging technology, the structure of the wafer W processed in the thinning stage tends to be more complex, gradually evolving from the processing of a single material to the processing of composite materials, including PI glue (polyimide), DAF (chip bonding film), EMC (epoxy resin molding compound), etc. used for wafer packaging or bonding. When the grinding wheel 100 processes composite materials, due to the simultaneous presence of heterogeneous materials such as epoxy resin materials, metal materials, silicon, and glue, the debris after grinding (or called contaminants 124) will adhere to the side wall or the bottom of the grinding teeth 120 as the grinding wheel 100 rotates, as Figure 6 shown in which the contaminants 124 may enter the pores 122 inside the grinding teeth 120. The presence of the contaminants 124 causes the grinding wheel 100 to become dull and the self-sharpening ability of the grinding wheel 100 is insufficient, affecting the grinding removal amount and removal efficiency of the grinding wheel 100 for the wafer W and ultimately affecting the surface processing quality of the wafer. "Self-sharpening" refers to the ability of the grinding wheel 100 to expose sharp abrasive grains 121 to maintain cutting performance.

[0033] In the prior art, the self-sharpening of the grinding wheel 100 is usually maintained by replacing the grinding wheel 100 or adjusting the processing process parameters. However, replacing the grinding wheel 100 has a high cost and is prone to introducing operation errors, making it difficult to meet the requirements of high-precision and high-efficiency processing. And the usual cleaning structure directly flushes the contaminants 124 on the surface of the grinding teeth 120 in a fixed orientation. It does not consider the bonding property of the abrasive grains 121 themselves and usually flushes away the abrasive grains 121, causing damage to the grinding teeth 120 themselves, making the grinding teeth 120 wear out too fast, affecting the service life of the grinding wheel 100, resulting in frequent replacement of the grinding wheel 100, reducing the overall processing efficiency and increasing the processing cost.

[0034] To this end, the present application provides a device for enhancing the self-sharpening property of a grinding wheel and a method for enhancing the self-sharpening property of a grinding wheel using the same. The device for enhancing the self-sharpening property of a grinding wheel can be used in the aforementioned wafer thinning equipment. As Figure 7 FIG. shows a schematic diagram of a device for enhancing the self-sharpening property of a grinding wheel according to an embodiment of the present application. It can be arranged at a position outside the wafer W of the grinding wheel 100. Preferably, it is arranged downstream of the wafer W along the rotation direction of the grinding wheel 100. For example, Figure 3 at the position indicated by the dashed circle A in FIG. It can be Figure 3 with the dotted line connecting the centers of the wafer W and the grinding wheel 100 as the boundary, divide the part of the grinding wheel 100 outside the wafer W into two segments. The segment moving towards the wafer W ( Figure 3 the upper side of the dotted line at the midpoint) is regarded as being upstream of the wafer W, and the segment moving away from the wafer W is regarded as being downstream of the wafer W. In an alternative embodiment, the device for enhancing the self-sharpening property of a grinding wheel is slidably arranged on an arc track. The arc track is arranged below the grinding wheel 100 and matches the radius of the grinding wheel 100. The device for enhancing the self-sharpening property of a grinding wheel moves along the arc track to align with different positions of the grinding wheel 100. For example, when the grinding wheel 100 changes the rotation direction, the device for enhancing the self-sharpening property of a grinding wheel can be changed to be arranged downstream of the wafer W along the rotation direction of the grinding wheel 100, or based on the actual cleaning and self-sharpening enhancement requirements of the grinding wheel 100, appropriately adjust the position of the device for enhancing the self-sharpening property of a grinding wheel. In another alternative embodiment, devices for enhancing the self-sharpening property of a grinding wheel can be respectively arranged on both sides of the dotted line to turn on the corresponding device for enhancing the self-sharpening property of a grinding wheel when the grinding wheel 100 changes the rotation direction, that is, turn on the device for enhancing the self-sharpening property of a grinding wheel downstream of the wafer W along the rotation direction of the grinding wheel 100, so as to timely flush, cool down and restore the self-sharpening property of the ground grinding tooth 120.

[0035] The device for enhancing the self-sharpening property of a grinding wheel mainly includes three flushing devices 200 respectively located on the inner side, outer side and bottom of the grinding wheel 100. Figure 7Only one molar 120 is schematically shown. The left side of it is the inner side of the grinding wheel, the right side is the outer side of the grinding wheel, and the lower part is the bottom of the grinding wheel. Three flushing devices 200 can be arranged at the same circumferential position of the grinding wheel 100, or can be arranged at different circumferential positions of the grinding wheel 100 with a slight dislocation. The flushing device 200 has a swingable nozzle 210, and the nozzle 210 is used to spray the cleaning liquid 211 onto the grinding wheel 100. Through the nozzle 210 swingable within the swing range, the cleaning liquid 211 sprayed by the flushing device 200 can reciprocally swing within the swing range to flush the grinding wheel 100, so as to enhance the vibration of the cleaning liquid 211 on the grinding wheel 100, make the contaminants 124 easier to loosen and fall off, and improve the cleaning effect. The nozzle 210 can be set to a conical shape that gradually tapers towards the molar 120 to achieve the effect of increasing the liquid spraying pressure. In addition, a pressure booster can be provided in the nozzle 210, or a pressure booster can be arranged between the nozzle 210 and the supply source of the cleaning liquid 211, so that the nozzle 210 sprays the pressurized cleaning liquid 211, prompting the contaminants 124 on the grinding wheel 100 to be flushed and loosened, and enhancing the cleaning effect. More preferably, the flushing device 200 can also be provided with an ultrasonic generator 220, and the ultrasonic generator 220 makes the cleaning liquid 211 generate ultrasonic vibration to further enhance the flushing force on the contaminants 124, which helps to remove the contaminants 124 on the grinding wheel 100.

[0036] The grinding wheel self-sharpening enhancement device further includes a controller (not shown), and the controller is electrically connected to the three flushing devices 200 respectively, and is used to regulate parameters such as the opening and closing, liquid spraying pressure, flushing direction, swing frequency, ultrasonic vibration frequency, etc. of the three flushing devices 200, so as to protect the molar 120 from being flushed and worn while removing the contaminants 124 on the grinding wheel 100 and enhancing the self-sharpening of the grinding wheel 100.

[0037] In an alternative embodiment, more flushing devices 200 can also be arranged at different positions of the grinding wheel 100 to enhance the cleaning effect. Or for considerations such as saving space, according to the actual situation of the contaminants 124, the flushing device 200 at the bottom, or the flushing device 200 on the inner side or the outer side can also be omitted.

[0038] Figure 8 The flushing schematic diagram of the flushing device 200 on the side part (inner side or outer side) of the grinding wheel 100 is shown; Figure 9 The flushing schematic diagram of the flushing device 200 at the bottom of the grinding wheel 100 is shown. During the process of forming the molar 120, affected by the consolidation process and the nature of the adhesive 123 itself, the abrasive grains 121 are usually more likely to be cross-linked and bonded horizontally, making the horizontal bonding between the abrasive grains 121 stronger and the vertical bonding weaker. In addition to flushing the contaminants 124, for the grinding wheel 100, Figure 8 the flushing device 200 on the side part in usually mainly functions to overcome the horizontal bonding and make the abrasive grains 121 horizontally loose, Figure 9The flusher 200 at the bottom in [description] usually mainly functions to overcome vertical adhesion and cause vertical loosening of the abrasive grains 121. Due to the differences between the lateral bonding force and the vertical bonding force, it is necessary to adaptively adjust parameters such as the liquid spraying pressure, swing frequency, and ultrasonic frequency of the flusher 200 on both sides and the flusher 200 at the bottom, so as to reduce the excessive loss of the abrasive grains 121 being washed off and the grinding teeth 120. In addition, during the grinding process of the grinding wheel 100, the grinding wheel 100 is in a rotating state, and the rotation of the grinding wheel 100 will drive the surrounding air to move together, forming an air layer with speed and pressure. When the pressurized cleaning liquid 211 sprayed by the flusher 200 on the inner or outer side flushes the side of the grinding wheel 100, this air layer will generate a certain resistance to the cleaning liquid 211, buffering and dispersing the impact force of the cleaning liquid 211 on the grinding wheel 100. Therefore, as the speed of the grinding wheel 100 itself increases, considering the increased resistance of the air layer to the cleaning liquid 211 due to the increase in the speed and pressure of the air layer, the liquid spraying pressure and swing frequency of the flusher 200 can be appropriately increased to break the air layer and achieve an effective impact on the grinding wheel 100. The rotation of the grinding wheel 100 results in an unclear formation of the air layer at its bottom, making the buffering and dispersing effect of the air layer on the impact force of the cleaning liquid 211 relatively small when the flusher 200 at the bottom flushes perpendicularly to the bottom surface of the grinding wheel 100. Therefore, under the same parameters such as the speed and pressure of the cleaning liquid 211, the bottom of the grinding wheel 100 is more easily affected by the impact force of the cleaning liquid 211. Therefore, the liquid spraying pressure or swing frequency of the flusher 200 at the bottom can be appropriately less than that of the flusher 200 on the side, so that the impact force effect on the bottom of the grinding wheel 100 is consistent with that on the side, avoiding excessive impact force of the cleaning liquid 211 at the bottom and causing the abrasive grains 121 to fall off (such as Figure 9 shows the fallen abrasive grains 121), and the loss of the grinding teeth 120. In addition, when the adhesion state of the abrasive grains 121 is not easy to fall off and the adhesion state of the contaminants 124 is not easy to fall off, the parameters such as the liquid spraying pressure or swing frequency of the flusher 200 at the bottom can be appropriately increased to make it the same as or even greater than the liquid spraying pressure or swing frequency of the flusher 200 with a larger impact force on the side (the flusher 200 at the main flushing position in the following text), so as to remove stubborn contaminants 124, achieve a better cleaning effect, and protect the grinding teeth 120 while improving the self-sharpening of the grinding wheel 100.

[0039] In an alternative or preferred embodiment, such as Figure 2 and Figure 14As shown, the dressing device for enhancing the self-sharpening of the grinding wheel may further include a dresser 300 disposed below the grinding wheel 100. The dresser 300 mainly includes a dressing base 320 and a dressing head 310. The top of the dressing head 310 is configured with diamond particles 311 for dressing the surface of the grinding teeth 120 of the grinding wheel, removing contaminants 124 and improving the self-sharpening of the grinding wheel 100. The dressing base 320 can be disposed on the workbench 31 and configured to be movable up and down so that the dressing head 310 can move downward away from the grinding teeth 120 and move upward to abut against the grinding teeth 120. When the cleaning liquid 211 of the rinser 200 is sufficient to remove contaminants 124 and improve the self-sharpening of the grinding wheel 100, the dressing base 320 is in a low position to keep the dressing head 310 away from the grinding teeth 120 to prevent the dressing head 310 from excessively wearing the grinding teeth 120; when the adhesiveness of the contaminants 124 is relatively strong and the rinser 200 fails to remove them, the dressing base 320 moves upward to make the dressing head 310 abut against the grinding teeth 120 upward, so as to use the diamond particles 311 to remove stubborn contaminants 124. The dresser 300 can be configured to be rotatable about a vertical axis to perform rotary dressing on the grinding wheel 100.

[0040] Figure 15 FIG. shows a flowchart of a method for enhancing the self-sharpening of a grinding wheel according to an embodiment of the present application, which is executed by using the aforementioned dressing device for enhancing the self-sharpening of the grinding wheel. The method mainly includes: Step S1: Determine the main flushing position: Based on the position of the grinding line L where the grinding wheel 100 grinds the wafer W and the rotation direction of the wafer W, determine whether the grinding wheel 100 is performing outer-edge machining. If so, the main flushing position is the outside of the grinding wheel 100; if not, the main flushing position is the inside of the grinding wheel 100. As Figure 4 Or Figure 5 , the grinding line L usually extends from the center of the wafer W to the edge of the wafer W to achieve grinding of the entire surface of the wafer W during the rotation of the wafer W and the grinding wheel 100. Figure 4 And Figure 5 The rotation directions of the wafer W and the grinding wheel 100 are respectively shown by arrows in FIGS. and. Among them, in step S1, determining whether the grinding wheel 100 is performing outer-edge machining based on the position of the grinding line L where the grinding wheel 100 grinds the wafer W and the rotation direction of the wafer W includes: As Figure 4 , the rotation direction of the part of the wafer W located outside the grinding wheel 100 faces the grinding line L, and the rotation direction of the part of the wafer W located inside the grinding wheel 100 faces away from the grinding line L. At this time, the outer radial side of the grinding teeth 120 of the grinding wheel 100 mainly contacts the wafer W for grinding, and it can be determined as outer-edge machining. During grinding, more chips accumulate on the outside of the grinding wheel 100, more contaminants 124 adhere, and the grinding teeth 120 are more severely passivated; as Figure 5, the rotation direction of the part of the wafer W outside the grinding wheel 100 is away from the grinding line L, and the rotation direction of the part of the wafer W inside the grinding wheel 100 is towards the grinding line L. At this time, the radially inner side of the grinding teeth 120 of the grinding wheel 100 mainly contacts the wafer W for grinding, which can be determined as inner-edge machining. During grinding, more debris accumulates on the inner side of the grinding wheel 100, and more contaminants 124 adhere to it, and the grinding teeth 120 are severely dulled. After determining the main flushing position based on inner-edge machining or outer-edge machining, step S2 can be executed.

[0041] Step S2: Set the liquid spraying pressure, swing frequency, ultrasonic vibration frequency, etc. of the flusher 200 at the main flushing position to be greater than the corresponding parameters such as the liquid spraying pressure, swing frequency, ultrasonic vibration frequency, etc. of the flusher 200 on the opposite side. For example, if the main flushing position is outside the grinding wheel 100, set the liquid spraying pressure of the flusher 200 outside the grinding wheel 100 to be greater than the liquid spraying pressure of the flusher 200 inside the grinding wheel 100. Additionally, the liquid spraying volume, swing frequency, etc. of the flusher 200 outside the grinding wheel 100 can be further set to be greater than the corresponding parameters of the flusher 200 inside the grinding wheel 100. To save system energy consumption, the flusher 200 inside the grinding wheel 100 can also be turned off. The flusher 200 at the bottom of the grinding wheel 100 can be set so that the flushing direction is skewed towards the main flushing position, and the parameters such as the liquid spraying pressure and swing frequency can be less than or equal to the corresponding parameters such as the liquid spraying pressure and swing frequency of the flusher 200 at the main flushing position, or when the contaminants 124 are difficult to flush away, they are approximately equal to or slightly higher than the corresponding flushing parameters of the flusher 200 at the main flushing position.

[0042] The method further includes step S3: determining the flushing direction of the flusher 200 based on the adhesion state of the abrasive grains 121 forming the grinding wheel 100 and the adhesion state of the contaminants 124 on the grinding wheel 100. This step mainly sets whether the tangential component of the flushing direction of the flusher 200 on the inner side, outer side or bottom of the grinding wheel 100 is in the same direction as or opposite to the tangential speed of the grinding wheel 100, that is, whether the flushing direction of the flusher 200 is inclined along the rotation direction of the grinding wheel 100 or against the rotation direction of the grinding wheel 100. By comparing the magnitude of the (actual) feed speed of the grinding wheel 100 with the set feed speed and combining with the wear amount of the grinding wheel 100, it is possible to determine whether the adhesion state of the abrasive grains 121 and the contaminants 124 is easy to fall off or not easy to fall off. The wear amount of the grinding wheel 100 refers to the loss amount of the material of the grinding teeth 120 generated due to the friction between the grinding teeth 120 and the wafer W during the grinding of the wafer W, and the wear amount can be calculated by monitoring the height difference of the position of the grinding wheel 100 or the main shaft connected to the grinding wheel 100 when they are in contact before and after a grinding process. If the adhesion force of the abrasive grains 121 in the grinding teeth 120 is low and the adhesion state is easy to fall off, the abrasive grains 121 may fall off during the flushing of the grinding wheel 100 by the flusher 200, resulting in the wear amount of the grinding wheel 100 exceeding the normal wear amount range; if the adhesion force of the abrasive grains 121 is large and the adhesion state is not easy to fall off and the abrasive grains 121 do not fall off during the flushing process, the wear amount of the grinding wheel 100 will be within the normal wear amount range.

[0043] In a specific embodiment, such as Figure 10Figure 1 shows a schematic diagram (i.e., a bottom view) of the molar 120 and the flusher 200 on the side (inner or outer side) as observed from the bottom of the grinding wheel 100. For example, the initial direction of the flusher 200 at the main flushing position can be set such that the component of its direction along the tangent of the grinding wheel 100 is in the same direction as the tangential velocity of the grinding wheel 100 indicated by the hollow arrow. Gradually increase the liquid spraying pressure from the initial value to the maximum value. If the feed rate of the grinding wheel 100 gradually increases from a value lower than the set feed rate to be consistent with the set feed rate, it indicates that at the beginning, due to the too low initial value of the liquid spraying pressure, the contaminants 124 cannot be flushed out sufficiently. The adhesion of the contaminants 124 on the molar 120 hinders the actual feed of the grinding wheel 100, resulting in a feed rate lower than the set feed rate. Subsequently, as the liquid spraying pressure increases, the feed rate gradually increases to be consistent with the set feed rate, indicating that the contaminants 124 can be flushed out sufficiently. If during this process, the wear amount of the grinding wheel 100 exceeds the wear amount range, it means that the shedding of the contaminants 124 is accompanied by the shedding of the abrasive grains 121 themselves. Then, the adhesion state of the abrasive grains 121 can be determined as easily shedding. At this time, the component of the flushing direction along the tangent of the grinding wheel 100 can be kept in the same direction as the tangential velocity of the grinding wheel 100, and at the same time, appropriately reduce the liquid spraying pressure during the grinding process to appropriately reduce the impact force of the cleaning liquid 211 on the molar 120, reduce the shedding of the abrasive grains 121, and thereby slow down the wear of the grinding wheel 100. As Figure 10 shown by the dashed line of Figure 10 , when keeping the component of the flushing direction along the tangent of the grinding wheel 100 in the same direction as the tangential velocity of the grinding wheel 100, the nozzle 210 of the flusher 200 can also have a swing amplitude of 10 to 30 degrees, that is, swing within an angular range of, for example, 10 to 30 degrees, to promote the shedding of the contaminants 124. In the case where the adhesion state of the abrasive grains 121 is determined as easily shedding, the same flushing direction setting can also be adopted for the flusher 200 at the bottom, as Figure 11 Figure 2 shows a schematic diagram (i.e., a side view) of the molar 120 and the flusher 200 at the bottom as observed from the side of the grinding wheel 100.

[0044] In another case, for example, set the initial direction of the flusher 200 at the main flushing position such that the component of its direction along the tangent of the grinding wheel 100 is in the same direction as the tangential velocity of the grinding wheel 100, and gradually increase the liquid spraying pressure from the initial value to the maximum value. If the feed rate of the grinding wheel 100 is always lower than the set feed rate and the wear amount of the grinding wheel 100 is within the wear amount range, it indicates that during this process, the contaminants 124 are always in an insufficiently removed state, always hindering the feed of the grinding wheel 100, and the abrasive grains 121 of the grinding wheel 100 do not shed (otherwise, they would shed together with the contaminants 124 and the contaminants would be removed). From this, it can be determined that the adhesion state of the abrasive grains 121 is not easily shedding and the adhesion state of the contaminants 124 is not easily shedding. At this time, as Figure 12, the flushing direction of the flusher 200 can be changed so that the component of the flushing direction along the tangent of the grinding wheel 100 is opposite to the tangential speed of the grinding wheel 100, so as to enhance the flushing force by the counteraction of the cleaning liquid 211 and the movement of the grinding wheel 100. As Figure 12 shown by the dashed line, while keeping the component of the flushing direction along the tangent of the grinding wheel 100 opposite to the tangential speed of the grinding wheel 100, the nozzle 210 of the flusher 200 can also have a swing amplitude of 10 to 30 degrees, that is, swing within an angular range of, for example, 10 to 30 degrees, to promote the shedding of the contaminants 124. When the adhesion state of the abrasive grains 121 is not easy to shed and the adhesion state of the contaminants 124 is not easy to shed, the same flushing direction setting can also be adopted for the bottom flusher 200, as Figure 13 FIG. shows a schematic diagram of the molar 120 and the bottom flusher 200 observed from the side of the grinding wheel 100.

[0045] In an alternative embodiment, when the flusher 200 is set such that the component of the flushing direction along the tangent of the grinding wheel 100 is opposite to the tangential speed of the grinding wheel 100, the liquid spraying pressure is gradually increased from the initial value to the maximum value. If the feeding speed of the grinding wheel 100 is always lower than the set feeding speed and the wear amount of the grinding wheel 100 is within the wear amount range, it indicates that the contaminants 124 are too stubborn and the flusher 200 can no longer remove the contaminants 124 and improve the self-sharpening of the grinding wheel 100. At this time, the dresser 300 with diamond particles 311 at the top can be abutted against the bottom of the grinding wheel 100 to grind and dress the molar 120.

[0046] In an alternative embodiment, the operation of gradually increasing the liquid spraying pressure from the initial value to the maximum value can also be replaced by gradually increasing the swing frequency from the initial value to the maximum value to determine the adhesion state of the abrasive grains 121 or the contaminants 124. In addition, the initial selection and determination process of the above flushing direction is carried out using the flusher 200 at the main flushing position. In an alternative embodiment, other flushers 200 can also be used.

[0047] Furthermore, the method may also include step S4: adjusting the spray pressure and swing frequency of the flusher 200 based on the ratio of the feed speed of the grinding wheel 100 to the set feed speed during the grinding process. Specifically, when the ratio of the feed speed of the grinding wheel 100 to the set feed speed is lower than the set range, it means that the attachment of the pollutants 124 hinders the feeding of the grinding wheel 100, and it is necessary to increase the spray pressure and / or swing frequency of the flusher 200 to enhance the flushing of the pollutants 124. Conversely, when it exceeds the set range, the spray pressure and / or swing frequency of the flusher 200 are reduced. The setting range can be 0.9 to 1.1. In addition, a speed alarm value can be set, such as a value between 1.1 and 1.3. When the ratio of the feed speed to the set feed speed exceeds the speed alarm value, an alarm signal is issued to indicate that the flushing pressure / or swing frequency setting is abnormal.

[0048] In an additional or alternative embodiment of step S4, the method may further include the following steps: based on the ratio of the machining current of the motor driving the grinding wheel 100 in the latter time period to the former time period in two consecutive time periods, the liquid spray pressure and the swing frequency of the flusher 200 are adjusted. Specifically, when the ratio of the machining current in two consecutive time periods exceeds the reference range, it indicates that the attachment of the pollutants 124 hinders the feeding of the grinding wheel 100, and it is necessary to increase the liquid spray pressure and / or the swing frequency; when the ratio of the machining current in two consecutive time periods is lower than the reference range, it indicates that the flushing causes more losses to the grinding wheel 100, and the liquid spray pressure and / or the swing frequency are reduced. The lower limit of the reference range can be set to 1. In addition, the normal machining state can be reached about 3 seconds after the grinding of the grinding wheel 100 starts, so a reference point can be collected, and the upper limit can be set to the ratio of the maximum current of the motor driving the grinding wheel 100 to the instantaneous current when grinding for 3 seconds. In addition, a current alarm value can be set, for example, the upper limit value of the aforementioned reference range can be taken. When the ratio of the processing current in two consecutive time periods exceeds the current alarm value, an alarm signal is issued to indicate that the spray pressure and swing frequency settings are abnormal.

[0049] In addition, in an optional embodiment, considering the existence of the air layer around the aforementioned grinding wheel 100, the method may further include increasing the spray pressure and the oscillation frequency of the inner, outer and bottom flushers 200 as the rotation speed of the grinding wheel 100 increases, and considering the difference in the side and bottom air layers, the increase in the spray pressure and the oscillation frequency of the inner and outer flushers 200 may be greater than the increase in the spray pressure and the oscillation frequency of the bottom flusher 200, so as to improve the self-sharpening property of the grinding wheel through flushing while reducing the shedding of abrasive particles caused by flushing, thereby ensuring the life of the grinding wheel.

[0050] In addition, since increasing parameters such as the liquid spraying pressure, the swing frequency, the liquid spraying volume, the liquid spraying speed, and the ultrasonic vibration frequency are all ways to increase the impact force of the cleaning liquid 211 on the grinding tooth 120, the above-mentioned adjustment methods for the liquid spraying pressure or the swing frequency are also applicable to the adjustment of parameters such as the liquid spraying volume, the liquid spraying speed, and the ultrasonic vibration frequency. Reducing the swing amplitude of the nozzle 210 will cause the cleaning liquid 211 to swing within a reduced range, making the cleaning liquid 211 act more concentratedly on the grinding tooth 120. Therefore, the adjustment method for the swing amplitude is opposite to the above-mentioned adjustment methods for the liquid spraying pressure or the swing frequency, that is, when it is necessary to increase the impact force, the swing amplitude is reduced, and when it is necessary to reduce the impact force, the swing amplitude is increased. In addition, for the adjustment of the flushing parameters of the flusher 200 described above, the adjustment methods (increasing or decreasing) for the flushing parameters of any flusher 200 are the same, and only the adjustment amplitudes may be different. Therefore, it is not specifically specified whether it is the inner, outer, or bottom flusher 200.

[0051] It should be understood that the step sequence in the above method for enhancing the self-sharpening of the grinding wheel is only exemplary. According to actual control or operation requirements or the display of equipment monitoring, the execution sequence of each step can be appropriately adjusted, or one or more of the above steps can be executed alternately or repeatedly.

[0052] The present application also provides a computer storage medium, on which a computer program is stored. When the program is executed by a processor, the above-mentioned method for enhancing the self-sharpening of the grinding wheel is implemented.

[0053] According to the technical solution of the present application, especially when the wafer is composed of a composite material, the adhesion characteristics of the abrasive grains 121 of the grinding wheel 100 and the complexity and adhesion characteristics of the contaminants 124 are fully considered. In order to improve the self-sharpening of the grinding wheel 100 and avoid excessive wear of the grinding wheel 100, by studying the correlation between the main processing positions of the grinding wheel 100 and the change trends of processing parameters such as the processing current and the feed speed and the main adhesion positions of the contaminants 124, the adhesion characteristics of the abrasive grains 121 and the contaminants 124, the settings and adjustment methods of parameters such as the main flushing positions, the flushing directions, the liquid spraying pressure, and the swing frequency of the flusher 200 are determined, as well as the coordination relationship between the side flusher 200 and the bottom flusher 200. Thus, by means of flushing, while performing targeted flushing on different positions and angles of the grinding wheel 100, the self-sharpening of the grinding wheel 100 is effectively improved, effective protection is provided for the grinding tooth 120, damage to the grinding tooth 120 during flushing is avoided, the service life of the grinding wheel 100 is guaranteed, the replacement frequency of the grinding wheel 100 is reduced, and the grinding and thinning effect and the grinding efficiency of the grinding wheel 100 are improved.

[0054] The above embodiments are only used to illustrate the embodiments of the present application, rather than to limit the embodiments of the present application. Those of ordinary skill in the relevant technical field can also make various changes and modifications without departing from the spirit and scope of the embodiments of the present application. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present application. The patent protection scope of the embodiments of the present application shall be defined by the claims.

Claims

1. A method for enhancing the self-sharpening property of a grinding wheel, the grinding wheel being used for grinding a wafer in a wafer thinning device, characterized in that, A washer is provided on the inner side, outer side, and bottom of the grinding wheel respectively, and the washer sprays cleaning liquid onto the grinding wheel. The method includes: Determine the main flushing position: Based on the position of the grinding line where the grinding wheel grinds the wafer and the rotation direction of the wafer, determine whether the grinding wheel is performing outer-edge machining. If so, the main flushing position is the outer side of the grinding wheel; if not, the main flushing position is the inner side of the grinding wheel. Set the liquid spraying pressure and swing frequency of the washer at the main flushing position to be greater than those of the washer on the opposite side respectively. Determine the flushing direction of the washer based on the adhesion state of the abrasive grains forming the grinding wheel and the adhesion state of contaminants on the grinding wheel. Adjust the liquid spraying pressure and swing frequency of the washer based on the ratio of the feed speed of the grinding wheel during grinding to the set feed speed.

2. The method for enhancing the self-sharpening property of a grinding wheel according to claim 1, characterized in that, The method further includes: As the rotation rate of the grinding wheel increases, increase the liquid spraying pressure and swing frequency of the washers on the inner side, outer side, and bottom to reduce the dispersion effect of the air layer around it caused by the rotation of the grinding wheel, and the increase amplitude of the liquid spraying pressure and swing frequency of the washers on the inner side and outer side is greater than that of the washer on the bottom.

3. The method for enhancing the self-sharpening property of the grinding wheel according to claim 1, wherein, The grinding line extends from the center of the wafer to the edge of the wafer. Determining whether the grinding wheel is performing outer-edge machining based on the position of the grinding line where the grinding wheel grinds the wafer and the rotation direction of the wafer includes: When the rotation direction of the part of the wafer outside the grinding wheel faces the grinding line, it is determined as outer-edge machining. When the rotation direction of the part of the wafer outside the grinding wheel deviates from the grinding line, it is determined as inner-edge machining.

4. The method for enhancing the self-sharpening property of the grinding wheel according to claim 1, characterized in that, Determining the flushing direction of the washer based on the adhesion state of the abrasive grains forming the grinding wheel and the adhesion state of contaminants on the grinding wheel includes: Set the initial direction of the washer so that the component of its direction along the tangent of the grinding wheel is in the same direction as the tangential velocity of the grinding wheel. Gradually increase the liquid spraying pressure from the initial value to the maximum value. If the feed speed of the grinding wheel gradually increases from being lower than the set feed speed to being consistent with the set feed speed and the wear amount of the grinding wheel exceeds the wear amount range, determine that the adhesion state of the abrasive grains is easy to fall off, and keep the component of the flushing direction along the tangent of the grinding wheel in the same direction as the tangential velocity of the grinding wheel. If the feed speed of the grinding wheel is always lower than the set feed speed and the wear amount of the grinding wheel is within the wear amount range, determine that the adhesion state of the abrasive grains is not easy to fall off and the adhesion state of the contaminants is not easy to fall off, and set the flushing direction of the washer so that the component of the flushing direction along the tangent of the grinding wheel is in the opposite direction to the tangential velocity of the grinding wheel.

5. The method for enhancing the self-sharpening property of the grinding wheel according to claim 4, wherein The method further includes: When the adhesion state of the abrasive grains is not easy to fall off and the adhesion state of the contaminants is not easy to fall off, increase the liquid spraying pressure and swing frequency of the washer on the bottom.

6. The method for enhancing the self-sharpening property of a grinding wheel according to claim 4, wherein, The method further includes: when the flushing direction of the flusher is set such that the tangential component along the grinding wheel is opposite to the tangential speed of the grinding wheel, gradually increasing the liquid spraying pressure from an initial value to a maximum value; if the feed speed of the grinding wheel is always lower than the set feed speed and the wear amount of the grinding wheel is within the wear amount range, pressing a dresser with diamond particles at the top against the bottom of the grinding wheel for grinding and dressing.

7. The method for enhancing the self-sharpening property of a grinding wheel according to claim 1, characterized in that, Adjusting the liquid spraying pressure and swing frequency of the flusher based on the ratio of the feed speed of the grinding wheel to the set feed speed during the grinding process includes: when the ratio of the feed speed of the grinding wheel to the set feed speed is lower than the set range, increasing the liquid spraying pressure and swing frequency of the flusher; when the ratio of the feed speed of the grinding wheel to the set feed speed exceeds the set range, decreasing the liquid spraying pressure and swing frequency of the flusher. The set range is from 0.9 to 1.

1.

8. The method for enhancing the self-sharpening property of a grinding wheel according to claim 1, wherein The method further includes: adjusting the liquid spraying pressure and swing frequency of the flusher based on the ratio of the machining currents of the motor driving the grinding wheel in two consecutive time periods.

9. The method for enhancing the self-sharpening property of a grinding wheel according to claim 8, wherein Adjusting the liquid spraying pressure and swing frequency of the flusher based on the ratio of the machining currents of the motor driving the grinding wheel in two consecutive time periods includes: when the ratio of the machining currents in two consecutive time periods exceeds the reference range, increasing the liquid spraying pressure and swing frequency; when the ratio of the machining currents in two consecutive time periods is lower than the reference range, decreasing the liquid spraying pressure and swing frequency. The lower limit value of the reference range is 1, and the upper limit value is the ratio of the maximum current of the motor driving the grinding wheel to the instantaneous current during 3 seconds of grinding.

10. The method for enhancing the self-sharpening property of a grinding wheel according to claim 1, characterized in that, The flusher is configured with an ultrasonic generator, and the ultrasonic generator causes the cleaning liquid to generate ultrasonic vibrations.

11. The method for enhancing the self-sharpening property of a grinding wheel according to any one of claims 1 to 10, characterized in that, Two groups of flushers are respectively arranged on both sides of the central connection line between the wafer and the grinding wheel. Each group of flushers respectively includes the flushers located inside, outside, and at the bottom of the grinding wheel. The method further includes: according to the rotation direction of the grinding wheel, turning on a group of flushers downstream of the wafer along the rotation direction of the grinding wheel.

12. A grinding wheel self-sharpening enhancement device for performing the grinding wheel self-sharpening enhancement method according to any one of claims 1-10, characterized in that, Including: Three flushers respectively located inside, outside, and at the bottom of the grinding wheel, the flushers having swingable nozzles for swingably spraying cleaning liquid onto the grinding wheel; A controller, the controller being electrically connected to the three flushers respectively, for regulating one or more parameters among the opening and closing, liquid spraying pressure, flushing direction, and swing frequency of the three flushers.

13. The grinding wheel self-sharpening enhancing device according to claim 12, characterized in that, The flusher further includes an ultrasonic generator, and the ultrasonic generator causes the cleaning liquid to generate ultrasonic vibrations to assist in removing contaminants on the grinding wheel.

14. A wafer thinning device, characterized in that, Including: A carrier table for adsorbing the wafer and driving the wafer to rotate; A grinding device including a grinding wheel for grinding the wafer; The grinding wheel self-sharpening enhancement device according to claim 12 or 13.

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