Cleaning method and cleaning equipment

Abstract

The invention relates to a cleaning method and cleaning equipment. The cleaning method comprises the steps that an object to be cleaned is cleaned through a cleaning device; the cleaning device comprises a cleaning pad which rubs the to-be-cleaned object when the to-be-cleaned object is cleaned; acquiring a current image of the cleaning pad; and in response to the condition that the gray scale of the current image reaches the cleaning condition of the cleaning pad, enabling a cleaning solution to act on the cleaning pad when the cleaning pad is idle. The residual condition of the powder particles on the cleaning pad is automatically judged according to the gray scale change of the cleaning pad, the cleaning liquid is sprayed to the cleaning pad to remove the powder particles when the residual powder particles reach a certain amount, pollution of the residual powder particles on the cleaning pad to a to-be-cleaned object can be reduced, and a good cleaning effect is obtained.

Description

Technical Field

[0001] This application relates to production equipment for semiconductor manufacturing, in particular to a cleaning method and also to a cleaning device. Background Art

[0002] During the manufacturing process of wafers for IGBT (Insulated Gate Bipolar Transistor) products, the wafers generally need to be thinned to 150 microns or even below 100 microns to meet the requirements of the products. When thinned to the above thickness, the wafers have almost no hardness and are difficult to process. An exemplary way to thin the wafers of IGBT products is Taiko thinning. Refer to Figure 1 , the difference between Taiko thinning and conventional thinning is that a taiko ring is reserved at the wafer edge without thinning, and the thickness of the taiko ring is the same as that before thinning, so as to improve the hardness of the wafer and make it not easily deformed in subsequent processing technologies.

[0003] During Taiko thinning, the front side of the wafer is generally pasted with a film and adsorbed on a transfer arm, and the back side is ground and thinned by a grinding wheel. After thinning, the front and back sides of the wafer are cleaned.

[0004] However, for the cleaning of the front side of the wafer after thinning, sometimes there is a problem that powder particles remain on the wafer edge after cleaning. Summary of the Invention

[0005] Based on this, it is necessary to provide a cleaning method with better cleaning effect.

[0006] A cleaning method includes: cleaning an object to be cleaned through a cleaning device; the cleaning device includes a cleaning pad that frictions the object to be cleaned when cleaning the object to be cleaned; obtaining a current image of the cleaning pad; and in response to the gray scale of the current image reaching the cleaning condition of the cleaning pad, causing a cleaning liquid to act on the cleaning pad when the cleaning pad is idle.

[0007] In the above cleaning method, the residual situation of powder particles on the cleaning pad is automatically judged through the change of the gray scale of the cleaning pad, and when the powder particles remain to a certain amount, the cleaning liquid is sprayed on the cleaning pad to remove the powder particles, which can reduce the pollution of the object to be cleaned by the powder particles remaining on the cleaning pad and obtain a better cleaning effect.

[0008] In one embodiment, the step of causing the cleaning liquid to act on the cleaning pad when the cleaning pad is idle in response to the gray scale of the current image reaching the cleaning condition of the cleaning pad includes: comparing the current image with the previously acquired image of the cleaning pad to obtain the gray scale change of the cleaning pad between the two images; and in response to the gray scale change reaching the cleaning condition of the cleaning pad, causing the cleaning liquid to act on the cleaning pad when the cleaning pad is idle.

[0009] In one embodiment, the step of obtaining the gray scale change of the cleaning pad between the two images includes: obtaining the gray scale change speed of the cleaning pad according to the gray scale change and the acquisition time interval between the two images; the gray scale change reaching the cleaning condition of the cleaning pad includes the gray scale change speed reaching a preset threshold; wherein, the process of the cleaning liquid acting on the cleaning pad has not occurred between the time points of the acquisition of the two images.

[0010] In one embodiment, the step of causing the cleaning liquid to act on the cleaning pad when the cleaning pad is idle in response to the gray scale change reaching the cleaning condition of the cleaning pad includes: determining the cleaning intensity and / or cleaning duration of the cleaning liquid on the cleaning pad according to the preset numerical interval in which the gray scale change speed is located.

[0011] In one embodiment, in response to the idle duration of the cleaning pad exceeding a preset value, the cleaning pad is humidified.

[0012] In one embodiment, both of the two images are images of the cleaning pad acquired when the cleaning pad is idle.

[0013] In one embodiment, the cleaning pad includes a sponge cleaning pad.

[0014] In one embodiment, the cleaning device includes a rotating mechanism, and the rotating mechanism is used to rotate the cleaning pad relative to the object to be cleaned, so that the cleaning pad rubs against the object to be cleaned to clean the object to be cleaned.

[0015] In one embodiment, the object to be cleaned is a wafer after the first main surface is thinned and the second main surface is attached with a sticky film.

[0016] In one embodiment, the object to be cleaned is a wafer after the first main surface Taiko thinning and the second main surface is attached with a sticky film.

[0017] A cleaning device, comprising: a cleaning pad for cleaning an object to be cleaned by rubbing against the object to be cleaned; a camera module for photographing the cleaning pad; a control module electrically connected to the camera module for sending a cleaning instruction when the gray scale of the current image of the cleaning pad reaches the cleaning condition of the cleaning pad; a spraying module electrically connected to the control module for spraying a cleaning liquid onto the cleaning pad when receiving the cleaning instruction.

[0018] For the above cleaning device, the residual situation of powder particles on the cleaning pad is automatically judged through the change of the gray scale of the cleaning pad, and when the residual powder particles reach a certain amount, a cleaning liquid is sprayed onto the cleaning pad to remove the powder particles, which can reduce the pollution of the object to be cleaned by the residual powder particles on the cleaning pad and obtain a better cleaning effect.

[0019] In one embodiment, the control module is used to compare the current image with the previously acquired image of the cleaning pad to obtain the gray scale change of the cleaning pad between the two images, and send the cleaning instruction when the gray scale change reaches the cleaning condition.

[0020] In one embodiment, the control module is used to obtain the gray scale change speed of the cleaning pad according to the gray scale change and the acquisition time interval between the two images; if the gray scale change speed reaches a preset threshold value, the cleaning instruction is sent.

[0021] In one embodiment, the spraying module includes: a nozzle; a liquid pipe connected to the nozzle and a liquid storage module; a pump connected to the liquid pipe and electrically connected to the control module; the control module is used to determine a spraying intensity signal according to the preset numerical interval where the gray scale change speed is located, and the pump adjusts the pressure applied to the cleaning liquid in the liquid pipe according to the spraying intensity signal; a switch connected to the liquid pipe and electrically connected to the control module, and the switch is used to turn on when receiving the cleaning instruction so that the cleaning liquid in the liquid pipe is ejected through the nozzle.

[0022] In one embodiment, the cleaning pad includes a sponge cleaning pad.

[0023] In one embodiment, the cleaning device includes a rotating mechanism for rotating the cleaning pad relative to the object to be cleaned, so that the cleaning pad rubs against the object to be cleaned to clean the object to be cleaned. Description of the Drawings

[0024] To more clearly illustrate the technical solutions in the embodiments of the present application or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 is a side view of wafers obtained by Taiko thinning and conventional thinning;

[0026] Figure 2 is a flowchart of a cleaning method in an embodiment of the present application;

[0027] Figure 3 is a flowchart of a cleaning method in another embodiment of the present application;

[0028] Figure 4 is a schematic structural diagram of a cleaning device in an embodiment of the present application. Detailed implementation manners

[0029] To facilitate the understanding of the present application, the following will describe the present application more comprehensively with reference to the relevant drawings. Embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs. The terms used in the description of the present application in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0031] It should be understood that when an element or layer is referred to as being "on", "adjacent to", "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected or coupled to the other element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on", "directly adjacent to", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types and / or portions, these elements, components, regions, layers, doping types and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type or portion from another element, component, region, layer, doping type or portion. Thus, without departing from the teachings of the present invention, the first element, component, region, layer, doping type or portion discussed below may be denoted as a second element, component, region, layer or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0032] Spatial relationship terms such as "below", "beneath", "under", "underneath", "above", "over", etc. may be used herein to describe the relationship of one element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relationship terms also encompass different orientations of the device during use and operation. For example, if the device in the figures is flipped, an element or feature described as "below" or "beneath" or "under" another element or feature will be oriented "above" the other element or feature. Thus, the exemplary terms "below" and "beneath" can include both an upper and a lower orientation. Additionally, the device may also include other orientations (such as, rotated 90 degrees or other orientations), and the spatial descriptors used herein are to be interpreted accordingly.

[0033] As used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprises / comprising" or "has / including" etc. specify the presence of the stated features, integers, steps, operations, components, parts or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts or combinations thereof. At the same time, in this specification, the term "and / or" includes any and all combinations of the related listed items.

[0034] After the Taiko thinning of the wafer, the front side of the wafer can be cleaned by scrubbing the front side of the wafer with a cleaning pad (cleaning mat) similar to a sponge material. For example, the wafer is rotated relative to the cleaning pad, and the cleaning pad rotates and scrubs the front side of the wafer to remove powder particles on the front side of the wafer. However, as the cleaning pad is used for a longer time, it is prone to adhering powder particles, resulting in the problem of powder particle residue on the edge of the wafer after cleaning. One solution is that during the routine maintenance of the cleaning equipment, the equipment engineer judges whether the cleaning pad needs to be replaced by observing the surface condition of the cleaning pad.

[0035] This application adds a self-cleaning device / step for the cleaning pad to prevent the reduction of the cleaning effect caused by the dirt of the cleaning pad itself in the cleaning step of the front side film pasting area of the wafer.

[0036] Figure 2 It is a flowchart of the cleaning method in an embodiment of this application, including the following steps:

[0037] S210, clean the object to be cleaned through a cleaning device.

[0038] The cleaning device is configured with a cleaning pad. In an embodiment of this application, the cleaning pad is a cleaning pad made of a sponge-like material, hereinafter referred to as a sponge cleaning pad. In an embodiment of this application, the object to be cleaned is a wafer with a sticky film pasted on the front side after the backside thinning is completed, that is, powder particles (such as silicon slag) will be formed on the surface after the backside thinning of the wafer, and it is necessary to remove them through the cleaning device. Further, this thinning is Taiko thinning, so a raised ring structure (taiko ring) is formed on the edge of the backside of the wafer. In an embodiment of this application, this sticky film can be a blue film, that is, an electronic grade tape.

[0039] S220, obtain the current image of the cleaning pad.

[0040] The cleaning pad is photographed through a camera module (such as a camera). It can be understood that it is difficult to obtain a clear image of the surface of the cleaning pad through the camera module during the operation of the cleaning device. Therefore, the current image of the cleaning pad can be obtained when the cleaning pad is idle after the cleaning device has been working continuously (the cleaning pad cleans the object to be cleaned) for a period of time. In the Taiko thinning process, the main grinding step takes the longest process time, which will cause some devices used in subsequent process steps to be idle, such as the cleaning pad.

[0041] S230, judge whether the gray level of the current image reaches the cleaning condition of the cleaning pad. If so, enter step S240.

[0042] The surface of the cleaning pad turns black after adhering to the powder particles (such as silicon slag) generated by wafer thinning. For example, the sponge cleaning pad itself is white and turns black after adhering to silicon slag. In an embodiment of the present application, a grayscale threshold is set. If the grayscale of the current image reaches the grayscale threshold, it is determined that the cleaning condition of the cleaning pad is met, and step S240 is entered.

[0043] S240, when the cleaning pad is idle, cause the cleaning liquid to act on the cleaning pad.

[0044] In an embodiment of the present application, the cleaning liquid is sprayed onto the cleaning pad through a nozzle to remove the powder particles. The cleaning liquid may include an alkali component, making it difficult for the silicon slag dust particles to contaminate the cleaning pad. It can be understood that if the determination result in step S230 is that the cleaning condition of the cleaning pad is not met, the cleaning pad is not cleaned. Whether step S240 is executed or the cleaning pad is not cleaned because the cleaning condition is not met, afterwards, step S210 can be returned to enable the cleaning device to clean the next object to be cleaned.

[0045] The above cleaning method automatically judges the residual situation of the powder particles on the cleaning pad through the grayscale change of the cleaning pad, sprays the cleaning liquid onto the cleaning pad to remove the powder particles when the residual amount of the powder particles reaches a certain amount, can reduce the pollution of the object to be cleaned by the powder particles remaining on the cleaning pad, obtain a better cleaning effect, and extend the service life (lifetime) of the cleaning pad.

[0046] Since the colors and grayscales of different cleaning pads in the clean state are different, in order to more accurately judge the situation of the cleaning pad adhering to the powder particles, it is possible to judge whether the cleaning condition of the cleaning pad is met according to the grayscale change of the cleaning pad images obtained before and after. In Figure 3 the shown embodiment, the cleaning method includes the following steps:

[0047] S310, clean the object to be cleaned through the cleaning device.

[0048] The same as step S210, which will not be elaborated here.

[0049] S320, obtain the current image of the cleaning pad.

[0050] The cleaning pad is photographed by the camera module, and the image is saved for standby. In an embodiment of the present application, the image of the cleaning pad is photographed each time the cleaning pad is idle. In an embodiment of the present application, the image of the cleaning pad can be photographed only once each time the cleaning pad is idle.

[0051] S330, compare the current image with the previously obtained cleaning pad image to obtain the grayscale change of the cleaning pad.

[0052] Obtain the grayscale change value of the cleaning pad between the front and rear images. The previously acquired cleaning pad images are also obtained through the camera module and saved for later use. In an embodiment of the present application, the previously acquired cleaning pad images are also obtained when the cleaning pad is idle.

[0053] S340, Determine whether the grayscale change of the cleaning pad between the two images reaches the cleaning condition of the cleaning pad. If so, proceed to step S350.

[0054] If the grayscale change value exceeds the preset trigger threshold, it is determined that the cleaning condition of the cleaning pad is reached, and proceed to step S350.

[0055] S350, Apply the cleaning liquid to the cleaning pad when the cleaning pad is idle.

[0056] The same as step S240, which will not be elaborated here. After this step is completed, a photograph of the cleaning pad can be taken for use as the "previously acquired cleaning pad image" when step S330 is executed again.

[0057] In Figure 3 the illustrated embodiment, judging the residual situation of powder particles on the cleaning pad by the grayscale change of the cleaning pad in the image twice before and after is more accurate than the solution of judging only by whether the grayscale of the current cleaning pad image reaches the grayscale threshold.

[0058] For the sponge cleaning pad, it is white when new and gradually turns black as the usage time increases. Therefore, it will interfere with judging the situation of residual powder particles on the cleaning pad through the gray scale. To solve this problem, in an embodiment of the present application, step S330 includes obtaining the gray scale change speed of the cleaning pad according to the gray scale change of two images (the previously obtained cleaning pad image can be the image obtained in step S320 when the cleaning pad was idle last time) and the acquisition time interval of the two images (the shooting time should be recorded when obtaining the image of the cleaning pad). That is, divide the gray scale change value of the cleaning pad between the two images before and after by the time interval between the two image acquisitions to obtain the gray scale change speed. Correspondingly, in step S340, if the gray scale change speed reaches the preset threshold, the cleaning condition of the cleaning pad is reached, and step S350 is entered. It can be understood that after a certain amount of powder particles adhere to the sponge cleaning pad, the gray scale will change sharply (turn black sharply). Therefore, the situation of residual powder particles on the cleaning pad can be judged by the gray scale change speed. Among them, step S350 has not been experienced between the time points when the two images are obtained. That is, in the embodiment of judging whether the cleaning condition is met through the gray scale change speed, step S350 should not have passed between the acquisition times of the two images compared in step S330. Further, if the cleaning device works continuously for a long time, the time interval between the two image acquisitions will be very long. Therefore, in an embodiment of the present application, if the time interval between the two image acquisitions before and after exceeds the preset time threshold, it is judged whether the gray scale of the current image reaches the gray scale threshold. If so, step S350 is executed.

[0059] In an embodiment of the present application, several gray scale thresholds are set in step S230, so as to divide multiple numerical intervals. The larger the gray scale value of the current image (that is, the later the numerical interval), the greater the cleaning intensity of the cleaning liquid on the cleaning pad and / or the longer the cleaning duration. If the gray scale of the current image exceeds the first gray scale threshold, the cleaning liquid acts on the cleaning pad with the first cleaning intensity when the cleaning pad is idle, and / or the cleaning liquid acts on the cleaning pad with the first cleaning duration when the cleaning pad is idle; if the gray scale of the current image exceeds the second gray scale threshold, the cleaning liquid acts on the cleaning pad with the second cleaning intensity when the cleaning pad is idle, and / or the cleaning liquid acts on the cleaning pad with the second cleaning duration when the cleaning pad is idle; where the first gray scale threshold is less than the second gray scale threshold, the first cleaning intensity is less than the second cleaning intensity, and the first cleaning duration is less than the second cleaning duration.

[0060] In one embodiment of the present application, several trigger thresholds are set in step S340, thereby dividing multiple numerical intervals. The greater the gray-scale change value (i.e., the later the numerical interval), the greater the cleaning intensity of the cleaning liquid on the cleaning pad and / or the longer the cleaning duration. If the gray-scale change value reaches the first trigger threshold, the cleaning liquid acts on the cleaning pad with the third cleaning intensity and / or for the third cleaning duration when the cleaning pad is idle; if the gray-scale change value exceeds the second trigger threshold, the cleaning liquid acts on the cleaning pad with the fourth cleaning intensity and / or for the fourth cleaning duration when the cleaning pad is idle; wherein, the first trigger threshold is less than the second trigger threshold, the third cleaning intensity is less than the fourth cleaning intensity, and the third cleaning duration is less than the fourth cleaning duration.

[0061] In one embodiment of the present application, a pump connected to the nozzle is provided, and the cleaning intensity of the cleaning liquid on the cleaning pad is adjusted by adjusting the pressure applied by the pump to the cleaning liquid. The spraying intensity signal is determined according to the gray scale or the gray-scale change value. If the gray scale of the current image reaches the first gray-scale threshold, the cleaning liquid acts on the cleaning pad with the first spraying volume and / or the first spraying speed through the nozzle when the cleaning pad is idle; if the gray scale of the current image reaches the second gray-scale threshold, the cleaning liquid acts on the cleaning pad with the second spraying volume and / or the second spraying speed through the nozzle when the cleaning pad is idle; wherein, the first gray-scale threshold is less than the second gray-scale threshold, the first spraying volume is less than the second spraying volume, and the first spraying speed is less than the second spraying speed. If the gray-scale change value exceeds the first trigger threshold, the cleaning liquid acts on the cleaning pad with the third spraying volume and / or the third spraying speed through the nozzle when the cleaning pad is idle; if the gray-scale change value exceeds the second trigger threshold, the cleaning liquid acts on the cleaning pad with the fourth spraying volume and / or the fourth spraying speed through the nozzle when the cleaning pad is idle; wherein, the first trigger threshold is less than the second trigger threshold, the third spraying volume is less than the fourth spraying volume, and the third spraying speed is less than the fourth spraying speed.

[0062] In one embodiment of the present application, a convolutional neural network big data analysis is used to determine whether the gray scale of the current image of the cleaning pad meets the cleaning conditions of the cleaning pad.

[0063] In one embodiment of the present application, the cleaning method also needs to obtain the idle duration of the cleaning pad. If the idle duration exceeds the preset value, the cleaning pad is humidified. In one embodiment of the present application, the humidification is also performed through the nozzle. The nozzle can be respectively connected to a container filled with cleaning liquid and a container filled with water (such as deionized water) through different liquid pipes (water pipes), and different switches are used to control whether the nozzle sprays the cleaning liquid for cleaning or the water for humidification.

[0064] In one embodiment of the present application, the cleaning device includes a rotating mechanism. The rotating mechanism is used to rotate the cleaning pad relative to the object to be cleaned, so that the cleaning pad rubs against the object to be cleaned to clean the object to be cleaned. In one embodiment of the present application, the rotating mechanism rotates the side of the wafer with a blue film attached (non-thinned side) after Taiko thinning on multiple sponge cleaning pads to wipe off powder particles.

[0065] The present application correspondingly provides a cleaning device. Figure 4 FIG. is a schematic structural diagram of a cleaning device in an embodiment of the present application, including a cleaning pad 110, a camera module 120, a control module 130, and a spraying module 140. The cleaning pad 110 is used to clean the object to be cleaned. In one embodiment of the present application, the cleaning pad is a sponge cleaning pad. In one embodiment of the present application, the object to be cleaned is a wafer with a sticky film attached to the front side after back thinning, that is, back thinning of the wafer will form powder particles on the surface, which need to be removed by the cleaning device. Further, the thinning is Taiko thinning, so a raised ring structure (taiko ring) is formed at the edge of the back side of the wafer. In one embodiment of the present application, the sticky film can be a blue film.

[0066] The camera module 120 is used to take pictures of the cleaning pad 110. The camera module 120 may include a camera. The control module 130 is electrically connected to the camera module 120 and is used to send a cleaning instruction when the gray scale of the cleaning pad 110 in the current image reaches the cleaning condition of the cleaning pad. The spraying module 140 is electrically connected to the control module 130 and sprays a certain amount of cleaning liquid on the cleaning pad 110 for a certain time when receiving the cleaning instruction.

[0067] For the above cleaning device, the residual situation of powder particles on the cleaning pad 110 is automatically judged through the gray scale change of the cleaning pad 110, and when the residual powder particles reach a certain amount, the cleaning liquid is sprayed on the cleaning pad to remove the powder particles, which can reduce the pollution of the object to be cleaned by the residual powder particles on the cleaning pad, obtain a better cleaning effect, and extend the service life (life time) of the cleaning pad 110.

[0068] In one embodiment of the present application, the cleaning device further includes a storage unit electrically connected to the camera module 120, and the images taken by the camera module 120 are stored in the storage unit. The control module 130 compares the current image of the cleaning pad 110 with the previous image of the cleaning pad 110 obtained, obtains the gray scale change of the cleaning pad 110 between the two images, and sends a cleaning instruction when the gray scale change reaches the cleaning condition of the cleaning pad. In one embodiment of the present application, the camera module 120 takes pictures of the cleaning pad 110 when the cleaning pad 110 is idle (that is, when the cleaning pad 110 is not cleaning the object to be cleaned).

[0069] In an embodiment of the present application, the control module 130 obtains the gray-scale change speed of the cleaning pad 110 according to the gray-scale change and the acquisition time interval between two images. That is, the gray-scale change value of the cleaning pad 110 between two consecutive images is divided by the time interval between two consecutive image acquisitions to obtain the gray-scale change speed. If the gray-scale change speed reaches a preset threshold, a cleaning instruction is sent.

[0070] In Figure 4 In the illustrated embodiment, the spraying module 140 includes a nozzle 142, a liquid pipe (water pipe) 144, a pump 146, and a switch 148. The liquid pipe 144 is connected to the nozzle 142 and the liquid storage module (i.e., a container filled with cleaning liquid). The pump 146 is connected to the liquid pipe 144 and is electrically connected to the control module 130. The control module 130 determines a spraying intensity signal according to the preset numerical interval in which the gray-scale change speed is located, and the pump 146 adjusts the pressure applied to the cleaning liquid in the liquid pipe according to the spraying intensity signal. That is, the greater the gray-scale change speed (in a value greater numerical interval), the greater the liquid spraying amount and spraying speed provided by the nozzle 142. The switch 148 is connected to the liquid pipe 144 and is electrically connected to the control module 130. The switch 148 is turned on for a preset duration when receiving the cleaning instruction, so that the cleaning liquid in the liquid pipe 144 is ejected through the nozzle 142. If the gray scale of the current image reaches the first gray-scale threshold, the cleaning liquid acts on the cleaning pad at the first liquid spraying amount and / or the first spraying speed through the nozzle when the cleaning pad is idle; if the gray scale of the current image reaches the second gray-scale threshold, the cleaning liquid acts on the cleaning pad at the second liquid spraying amount and / or the second spraying speed through the nozzle when the cleaning pad is idle; wherein, the first gray-scale threshold is less than the second gray-scale threshold, the first liquid spraying amount is less than the second liquid spraying amount, and the first spraying speed is less than the second spraying speed. If the gray-scale change value exceeds the first trigger threshold, the cleaning liquid acts on the cleaning pad at the third liquid spraying amount and / or the third spraying speed through the nozzle when the cleaning pad is idle; if the gray-scale change value exceeds the second trigger threshold, the cleaning liquid acts on the cleaning pad at the fourth liquid spraying amount and / or the fourth spraying speed through the nozzle when the cleaning pad is idle; wherein, the first trigger threshold is less than the second trigger threshold, the third liquid spraying amount is less than the fourth liquid spraying amount, and the third spraying speed is less than the fourth spraying speed.

[0071] In an embodiment of the present application, the cleaning liquid stored in the liquid storage module contains an alkali component.

[0072] In an embodiment of the present application, the cleaning device includes a rotating mechanism. The rotating mechanism is used to rotate the cleaning pad 110 relative to the object to be cleaned, so that the cleaning pad 110 rubs against the object to be cleaned to clean the object to be cleaned. In an embodiment of the present application, the rotating mechanism rotates the side of the wafer with a Taiko thinned and attached with a blue film (non-thinned side) on multiple sponge cleaning pads to erase powder particles.

[0073] In one embodiment of the present application, the nozzle 142 is also connected to a container filled with water (deionized water) through another liquid pipe. This liquid pipe is also configured with a switch. The cleaning device further includes a timer for counting the idle time of the cleaning pad 110. When the idle duration exceeds a preset value, the corresponding switch is turned on to cause the nozzle 142 to spray deionized water to humidify the cleaning pad 110.

[0074] The cleaning device and cleaning method of the present application are based on the same inventive concept. For the content not specifically described in the cleaning device, reference can be made to the introduction of the cleaning method above.

[0075] It should be understood that although the steps in the flowchart of the present application are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless specifically stated herein, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in the flowchart of the present application may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least some of the steps or stages in other steps or other steps.

[0076] In the description of this specification, the descriptions referring to terms such as "some embodiments", "other embodiments", "ideal embodiments", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0077] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features of the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0078] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A cleaning method, characterized in that, comprising: cleaning an object to be cleaned by a cleaning device; the cleaning device includes a cleaning pad that rubs the object to be cleaned when cleaning the object to be cleaned; acquiring a current image of the cleaning pad; in response to the gray level of the current image reaching the cleaning condition of the cleaning pad, causing a cleaning liquid to act on the cleaning pad when the cleaning pad is idle.

2. The cleaning method according to claim 1, characterized in that, the step of causing the cleaning liquid to act on the cleaning pad when the cleaning pad is idle in response to the gray level of the current image reaching the cleaning condition of the cleaning pad includes: comparing the current image with a previously acquired image of the cleaning pad to obtain the gray level change of the cleaning pad between the two images; in response to the gray level change reaching the cleaning condition of the cleaning pad, causing the cleaning liquid to act on the cleaning pad when the cleaning pad is idle.

3. The cleaning method according to claim 2, characterized in that, the step of obtaining the gray level change of the cleaning pad between the two images includes: obtaining the gray level change speed of the cleaning pad according to the gray level change and the acquisition time interval of the two images; the gray level change reaching the cleaning condition of the cleaning pad includes the gray level change speed reaching a preset threshold; wherein, the process of the cleaning liquid acting on the cleaning pad has not occurred between the time points of the acquisition of the two images.

4. The cleaning method according to claim 3, characterized in that, the step of causing the cleaning liquid to act on the cleaning pad when the cleaning pad is idle in response to the gray level change reaching the cleaning condition of the cleaning pad includes: determining the cleaning intensity and / or cleaning duration of the cleaning liquid on the cleaning pad according to the preset numerical interval in which the gray level change speed is located.

5. The cleaning method according to claim 2, characterized in that, further comprising: in response to the idle duration of the cleaning pad exceeding a preset value, humidifying the cleaning pad; and / or both of the two images are images of the cleaning pad acquired when the cleaning pad is idle.

6. The cleaning method according to claim 1, characterized in that, the cleaning pad includes a sponge cleaning pad; and / or the cleaning device includes a rotating mechanism for rotating the cleaning pad relative to the object to be cleaned, so that the cleaning pad rubs against the object to be cleaned to clean the object to be cleaned.

7. The cleaning method according to any one of claims 1-6, characterized in that, the object to be cleaned is a wafer after the first main surface is thinned and a sticky film is attached to the second main surface.

8. A cleaning device, characterized in that, comprising: a cleaning pad for rubbing against an object to be cleaned to clean the object to be cleaned; a camera module for photographing the cleaning pad; a control module electrically connected to the camera module for sending a cleaning instruction when the gray level of the current image of the cleaning pad reaches the cleaning condition of the cleaning pad; a spraying module electrically connected to the control module for spraying a cleaning liquid onto the cleaning pad when receiving the cleaning instruction.

9. The cleaning device according to claim 8, Characterized in that, the control module is configured to compare the current image with the previously acquired image of the cleaning pad, obtain the gray-scale change of the cleaning pad between the two images, and send the cleaning instruction when the gray-scale change reaches the cleaning condition.

10. The cleaning device according to claim 9, Characterized in that, the control module is configured to obtain the gray-scale change speed of the cleaning pad according to the gray-scale change and the acquisition time interval of the two images; if the gray-scale change speed reaches a preset threshold, send the cleaning instruction.

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