Wafer cleaning device, cleaning method and wafer thinning equipment

Abstract

The present invention proposes a wafer cleaning device, a cleaning method and a wafer thinning device. The wafer cleaning device is used for the wafer thinning device. The clamping wheel of the manipulator of the wafer thinning device holds the wafer in place for wafer cleaning. The wafer cleaning device includes: a spraying rotating member, which is used to spray a cleaning fluid onto the back of the wafer to be cleaned. A first flow channel is formed inside the spraying rotating member, and spray holes are distributed on the side of the spraying rotating member facing the back of the wafer. The spray holes are used to spray the cleaning fluid; a hollow rotating shaft, which is connected to the rotation center of the spraying rotating member, and a second flow channel is formed inside the hollow rotating shaft, and the first flow channel is connected to the second flow channel; and a driving mechanism, which is used to drive the hollow rotating shaft to drive the spraying rotating member to rotate while the spraying rotating member sprays the cleaning fluid onto the back of the wafer. The present invention uses non-contact back cleaning in wafer thinning, which can effectively avoid contamination, scratches and fragments on the back of the wafer.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing; more specifically, the present invention relates to a wafer cleaning device, a cleaning method and a wafer thinning equipment. Background Art

[0002] In the thinning process of the thinning and polishing machine, the robot uses a full-size suction cup to adsorb the wafer when it loads and unloads the wafer from the chuck of the grinding module. The residual silicon powder and crystal slag on the suction cup can easily cause cross contamination to the wafer.

[0003] In view of the above problems, the robot is optimized in the prior art. The upper wafer is adsorbed by a small suction cup, and the lower wafer is clamped by the edge. Based on this, after the thinning process is completed, the wafer is removed from the chuck of the grinding module by the robot. Before it is placed in the conveying assembly, the back of the wafer needs to be cleaned. Traditional contact cleaning methods such as roller brushes are prone to scratches on the back of the wafer, and even cause the risk of wafer breakage. Summary of the invention

[0004] In view of this, the present invention provides a wafer cleaning device, a cleaning method and a wafer thinning equipment, so as to solve or at least alleviate one or more of the above-mentioned problems and other problems existing in the prior art.

[0005] In order to achieve the above-mentioned object, a first aspect of the present invention provides a wafer cleaning device for a wafer thinning device, wherein a clamping wheel of a manipulator of the wafer thinning device holds the wafer in place for wafer cleaning, wherein the wafer cleaning device comprises:

[0006] A spray rotating member, the spray rotating member is used to spray a cleaning fluid onto the back side of the wafer to be cleaned, a first flow channel is formed inside the spray rotating member, and spray holes are distributed on the side of the spray rotating member facing the back side of the wafer, the spray holes are used to spray the cleaning fluid;

[0007] a hollow rotating shaft, the hollow rotating shaft being connected to the rotating center of the injection rotating member, a second flow channel being formed inside the hollow rotating shaft, the first flow channel being connected to the second flow channel; and

[0008] A driving mechanism is used to drive the hollow rotating shaft to drive the spray rotating member to rotate while the spray rotating member sprays cleaning fluid onto the back side of the wafer.

[0009] In the wafer cleaning device as described above, optionally, the spray rotating member extends along the entire diameter length of the wafer, the spraying direction of the cleaning fluid is inclined, and the rotation direction of the spray rotating member is consistent with the spraying direction of the cleaning fluid.

[0010] In the wafer cleaning device as described above, optionally, outward spray holes are provided at both ends of the spray rotating member, and the outward spray holes are used to clean the clamping wheel and the wafer portion blocked by the clamping wheel.

[0011] In the wafer cleaning device as described above, optionally, when performing wafer cleaning, the back side of the wafer maintains a preset distance from the upper surface of the spray rotating member, and the preset distance is 2 mm to 5 mm.

[0012] In the wafer cleaning device as described above, optionally, the clamping wheel is provided with radially inward fluid injection holes.

[0013] In the wafer cleaning device as described above, optionally, a fluid pressure sensor is provided at the fluid injection hole for measuring the fluid pressure at the fluid injection hole to determine whether the clamping wheel clamps the wafer normally:

[0014] When the fluid pressure is measured to be a higher first predetermined value, it is determined to be normal clamping;

[0015] When the fluid pressure is measured to be a lower second predetermined value, it is determined to be abnormal clamping.

[0016] In the wafer cleaning device as described above, optionally, the flow path of the cleaning fluid is provided with a compressed air source or a booster pump to increase the impact force of the sprayed cleaning fluid.

[0017] In the wafer cleaning device as described above, optionally, the flow path of the cleaning fluid is provided with an ultrasonic generator for generating high-frequency vibrations in the sprayed cleaning fluid.

[0018] In the wafer cleaning device as described above, optionally, the spray hole is in a strip shape, and the spray hole outputs a fan-shaped jet.

[0019] In the wafer cleaning device as described above, optionally, the injection fluid is a gas-liquid dual fluid.

[0020] In the wafer cleaning device as described above, optionally, a sponge strip extending the entire length of the spray rotating member is provided on the upper surface of the spray rotating member.

[0021] In the wafer cleaning device as described above, optionally, an oil stone and / or bristles are provided in the central area of ​​the spray rotating member, and an independent cleaning fluid spray hole is provided in the central area.

[0022] In order to achieve the aforementioned objective, a second aspect of the present invention provides a wafer thinning device, wherein the wafer thinning device comprises a wafer cleaning device as described in any one of the aforementioned first aspects.

[0023] In order to achieve the aforementioned objective, a third aspect of the present invention provides a method for cleaning a wafer in a wafer thinning device using the wafer cleaning device as described in any one of the aforementioned first aspects.

[0024] In the method as described above, optionally, the method comprises the following steps:

[0025] Using the robot to lower the wafer to a preset distance above the spray rotating member;

[0026] keeping the wafer stationary;

[0027] The spraying rotating part is started to clean the back side of the wafer.

[0028] The present invention uses non-contact backside cleaning during wafer thinning, which can effectively avoid contamination, scratches and breakage of the backside of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The disclosure of the present invention will become more apparent with reference to the accompanying drawings. It should be understood that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In the drawings:

[0030] Figure 1 A wafer thinning apparatus is schematically shown.

[0031] Figure 2 FIG. 2 shows a schematic diagram of scratches and contaminants on a wafer during contact cleaning of the wafer.

[0032] Figure 3 A schematic diagram of an embodiment of a wafer cleaning device according to the present invention is shown.

[0033] Figure 4 Shows Figure 3 Schematic bottom view of a wafer and a spray carousel of a wafer cleaning apparatus.

[0034] Figure 5 Shows Figure 3 A side view schematic diagram of the cleaning state of the wafer cleaning device.

[0035] Figure 6 Shows Figure 3 Schematic cross-sectional view of the jetting rotating part of the wafer cleaning device.

[0036] Figure 7 A schematic diagram showing another embodiment of a wafer cleaning device according to the present invention is shown.

[0037] Figure 8 A schematic diagram of a robot clamping wheel in a wafer cleaning device according to the present invention is shown.

[0038] Fig. 9 Shows Figure 8 The direction of water spray at the gripping wheel of the middle manipulator.

[0039] Fig.10 Shows Figure 8 The robot gripping wheel shows different clamping states of the wafer.

[0040] Figure markings: 1-wafer thinning equipment; 2-wafer cleaning device; 3-clamping wheel; 4-wafer; 5-injection rotating part; 6-injection hole; 7-hollow rotating shaft; 8-driving mechanism; 9-outward injection hole; 10-fluid injection hole; 21-equipment front-end module; 22-polishing module; 23-grinding module; 24-grinding spindle; 25-wafer carrier; 26-front-end measuring device; 27-first manipulator; 28-cleaning system; 29-drying system; 30-rear-end measuring device; 31-polishing system; 32-second manipulator; 33-conveying assembly; 34-wafer storage unit; 35-temporary storage unit; 36-mobile cache unit; 37-cleaning device; 38-grinding unit; 39-cleaning unit; 40-third manipulator; 41-base; 42-workbench; 43-suction cup; 44-grinding wheel. DETAILED DESCRIPTION

[0041] With reference to the accompanying drawings and specific embodiments, the structure, composition, characteristics and advantages of the wafer cleaning device, cleaning method and wafer thinning equipment of the present invention will be described below in an exemplary manner. However, all descriptions should not be used to form any limitations on the present invention.

[0042] For any single technical feature described or implied in the embodiments mentioned in this document, or any single technical feature displayed or implied in the accompanying drawings, the present invention still allows any combination or deletion between these technical features (or their equivalents) without any technical obstacles, and thus it should be considered that these more embodiments according to the present invention are also within the scope of the description of this document.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features.

[0044] Figure 1 A wafer thinning apparatus is schematically shown.

[0045] As shown in the figure, the wafer thinning device 1 includes a device front-end module 21, a polishing module 22, a grinding module 23 and a conveying component 33, etc.

[0046] The equipment front-end module 21 is used to realize the entry and exit of wafers, and the equipment front-end module 21 is arranged at the front end of the wafer thinning equipment 1. The equipment front-end module 21 is a transition module for transferring wafers from the outside to the inside of the equipment platform, and is used to realize the entry and exit of wafers to realize the "dry in and dry out" of wafers.

[0047] The grinding module 23 is used to grind and thin the wafer. The grinding may include rough grinding and fine grinding. The grinding module 23 is arranged at the end of the wafer thinning device 1 .

[0048] The polishing module 22 is used to perform chemical mechanical polishing on the wafer after the grinding is completed, and also has the function of transferring the wafer between these three modules (equipment front-end module 21, grinding module 23 and polishing module 22). The polishing module 22 is arranged between the equipment front-end module 21 and the grinding module 23.

[0049] Understandably, Figure 1 The wafer thinning device shown is only an example. In other implementations, the polishing module 22 may be omitted, and only the device front-end module 21 and the grinding module 22 are retained. In addition, the grinding module 22 may also include multiple grinding passes, such as 3 passes, 4 passes, 5 passes, etc. Similar to these modified embodiments, as long as they can achieve wafer grinding and thinning, they should fall within the protection scope of this application.

[0050] The equipment front-end module 21 includes a wafer storage unit 34 and a second robot 32. The wafer storage unit 34 is arranged at the front end side of the wafer thinning equipment 1, and the second robot 32 is arranged between the wafer storage unit 34 and the polishing module 22 to realize the transfer of wafers between the wafer storage unit 34 and the polishing module 22.

[0051] The second robot 32 may include a wafer pick-up and placement robot. The wafer pick-up and placement robot can rotate, extend, fold and shrink, and can also move along the transmission track. Here, the wafer pick-up and placement robot is a dry robot, which is used to pick up and place dry and clean wafers. The wafer pick-up and placement robot can take out the wafer to be processed from the wafer storage unit 34 and send it to the polishing module 22, and can also receive the processed wafer from the polishing module 22 and put it into the wafer storage unit 34.

[0052] The polishing module 22 may include a conveying assembly 33, a first robot 27, a polishing system 31, a drying system 29, and a back-end measuring device 30. The conveying assembly 33, the polishing system 31, the drying system 29, and the back-end measuring device 30 occupy the edges of the polishing module 22, respectively, and the first robot 27 is located in the center.

[0053] Specifically, the conveying assembly 33 is located on one side of the edge of the polishing module 22 and is distributed along the length direction of the equipment, and can connect the equipment front-end module 21 and the grinding module 23. The polishing system 31 is located on the other side edge of the polishing module 22, and is adjacent to the grinding module 23 and the conveying assembly 33 respectively. The drying system 29 and the rear-end measuring device 30 are located on another side edge of the polishing module 22, and are adjacent to the equipment front-end module 21, the conveying assembly 33 and the polishing system 31 respectively. The first manipulator 27 is close to the center of the polishing module 22, surrounded by the conveying assembly 33, the polishing system 31 and the drying system 29, and is used to realize the mutual transmission of wafers between the conveying assembly 33, the polishing system 31 and the drying system 29. In the illustrated embodiment, the conveying assembly 33 includes a temporary storage part 35 and a mobile cache part 36 for temporarily storing wafers and shipping wafers. The temporary storage part 35 is set at a position adjacent to the equipment front-end module 21, and is used to temporarily store or transfer wafers. The mobile cache part 36 is set along the direction from the equipment front-end module 21 to the grinding module 23, and can move in both directions.

[0054] In the illustrated embodiment, the first robot 27 is a polishing robot, which is used to transfer the ground wafers from the mobile cache unit 36 ​​to the polishing system 31, transfer the polished wafers from the polishing system 31 to the drying system 29, and transfer the cleaned wafers from the drying system 29 to the temporary storage unit 31.

[0055] After the wafer is taken out from the equipment front-end module 21, it is transported to the grinding module 23 for grinding via the conveying component 33; after the wafer is ground in the grinding module 23, it is transported to the polishing system 31 for polishing via the conveying component 33 and the first robot 27; after polishing and cleaning, the wafer is transported back to the equipment front-end module 21 via the first robot 27 and the conveying component 33.

[0056] The drying system 29 is used to clean and dry the polished wafers, and may include a horizontal brush cleaning device and a single-chamber cleaning device.

[0057] The grinding module 23 may include a grinding unit 38, a cleaning unit 39 and a third robot 40. The grinding unit 38 is used to perform wafer grinding and thickness measurement. Figure 1 As shown, the grinding unit 38 includes a base 41, a workbench 42 mounted on the base 41, a suction cup 43 disposed on the workbench 42, and a grinding wheel 44 corresponding to the position of the suction cup 43. The workbench 42 is used to carry the wafer and can rotate around its vertical center axis. Figure 1 As shown, in one embodiment, three suction cups 43 are provided, which can rotate between the rough grinding station, the fine grinding station and the loading and unloading station.

[0058] The two grinding wheels 44 respectively perform rough grinding and fine grinding. It is understandable that Figure 1This is only an example, and the number of the suction cup 43 and the grinding wheel 44 can also be other values. The cleaning unit 39 is used to clean, grind and clean the suction cup 43. The third manipulator 40 includes a grinding manipulator for transmitting wafers. The grinding manipulator refers to a manipulator used in the grinding module 23, which is used to transmit wafers between the grinding unit 38 and the conveying assembly 33, specifically, to transfer wafers between the suction cup 43 and the mobile cache 36 corresponding to the loading and unloading station. The third manipulator 40, i.e., the grinding manipulator, takes the wafer from the mobile cache 36 of the conveying assembly 33 and sends it to the grinding unit 38 for grinding. After grinding and cleaning are completed, the grinding manipulator takes the wafer from the grinding unit 38 and places it in the mobile cache 36 for subsequent transmission of the wafer. A pipeline that can be evacuated is provided inside the grinding manipulator to achieve vacuum adsorption of the wafer. Alternatively, the grinding manipulator can also be implemented by a mechanism with a clamping wheel. In one embodiment, the grinding manipulator can also drive the wafer to rotate.

[0059] like Figure 1 As shown, in one embodiment of the present invention, the grinding module 23 also includes a cleaning device 37, which is installed on the base 41 of the grinding module 23, located next to the workbench 42 and on the moving track of the grinding robot, and is used to clean the bottom surface of the wafer after grinding when the grinding robot transfers the wafer.

[0060] According to the wafer thinning device 1 of the present invention, after the thinning process is completed, the robot removes the wafer from the suction cup 43 in the form of edge clamping, and the wafer back cleaning is non-contact during the wafer removal process to avoid the risk of wafer breakage. After the cleaning is completed, the wafer is sent to the conveying component 33.

[0061] Figure 2 FIG. 2 shows a schematic diagram of scratches and contaminants on a wafer during contact cleaning of the wafer.

[0062] In the thinning and polishing machine, after the thinning process is completed, after the robot removes the wafer 4 from the suction cup 43 by edge clamping and before placing it on the conveying assembly, when cleaning the back of the wafer, contact cleaning such as rolling brushes or sponges can easily cause damage to the back of the wafer, such as Figure 2 The black spots scattered on the wafer in the figure are schematic diagrams of contaminants that are easily left behind when the wafer is contact-cleaned. The non-contact cleaning of the present invention can effectively solve the problems of scratches and contaminants caused by contact cleaning.

[0063] Figure 3 FIG. 2 is a schematic diagram showing an embodiment of a wafer cleaning device according to the present invention. The wafer cleaning device 2 shown in the figure can be Figure 1 The cleaning device 37 of the wafer thinning device 1 is not excluded. Figure 1The wafer cleaning device 2 is used for non-contact cleaning in other processes of the wafer thinning equipment 1 to avoid scratches, contact contamination, etc. on the wafer in these processes.

[0064] As shown in the figure, the robot arm of the wafer thinning device 1 (here can be Figure 1 The third robot 40) in the figure holds the wafer 4 in place for wafer cleaning. It should be noted that only the robot clamping wheel 3 is shown in the accompanying drawings, and other structures of the robot are not described in detail here. The figure only shows two clamping wheels that clamp the wafer 4 on one side. It can be understood that there can also be a clamping wheel on one side of the wafer 4 that is not shown, such as one or two, to cooperate to hold the wafer 4 in place so that the wafer 4 is in a position that is convenient for cleaning. For example, the position that is convenient for cleaning can be a horizontal position.

[0065] The figure also shows a wafer cleaning device 2. As can be seen from the figure, the wafer cleaning device 2 may include a spray rotating member 5, a hollow rotating shaft 7, and a driving mechanism 8. The spray rotating member 5 is kept at an appropriate distance from the wafer 4 in a non-contact manner, and the driving mechanism 8 is used to drive the spray rotating member 5 to rotate through the hollow rotating shaft 7. When cleaning the wafer, the wafer does not need to move, and the spray rotating member 5 can spray the cleaning liquid to the back of the wafer in a non-contact manner while rotating.

[0066] The spray rotating member 5 is used to spray the cleaning fluid onto the back side of the wafer 4 to be cleaned. The spray rotating member 5 is parallel to the wafer 4; and when the spray rotating member 5 rotates, the rotation plane of the spray rotating member 5 is parallel to the wafer 4, specifically, parallel to the back side of the wafer 4 to be cleaned. Figure 5 Schematic diagram of the spray rotating member 5 spraying cleaning fluid to the wafer 4 is shown in FIG. In different embodiments, the spray rotating member 5 may be in various specific forms as required. For example, the spray rotating member 5 may be in a disc shape, a long plate shape, a rod shape, etc., and may have a spray hole on the side facing the back of the wafer to spray the cleaning fluid to the back of the wafer. When the spray rotating member 5 rotates, the jet sprayed from the spray hole may cover the back of the entire wafer, which is conducive to comprehensive cleaning of the back of the wafer.

[0067] The hollow rotating shaft 7 may be connected to the rotation center of the spray rotating member 5. When the spray rotating member 5 sprays the cleaning fluid onto the back side of the wafer 4, the driving mechanism 8 drives the hollow rotating shaft 7 to drive the spray rotating member 5 to rotate. A second flow channel may be formed inside the hollow rotating shaft 7, and the first flow channel is connected to the second flow channel, so that the cleaning fluid from the external fluid source can flow to the spray hole through the second flow channel in the hollow rotating shaft 7 and the first flow channel in the spray rotating member 5, and is sprayed out from the spray hole to clean the back side of the wafer.

[0068] As shown in the figure, the driving mechanism 8 can be a motor. The motor drives the hollow shaft through a transmission mechanism. In the illustrated example, the transmission mechanism is a belt transmission, in which the transmission belt connects the motor and the hollow shaft through the pulleys on the motor and the hollow shaft for transmission, and the structure is simple and easy to assemble. In other embodiments, as needed, a gear set can also be provided for speed reduction transmission, and the transmission is more stable. It should be pointed out that it is not excluded that other forms of transmission mechanisms are used in certain embodiments; these embodiments should also fall within the scope of the present invention.

[0069] from Figure 3 It can be seen that when the wafer 4 is in the position to be spray-cleaned, the spray rotating member 5 and the wafer 4 are not in contact, but maintain an appropriate preset distance. Specifically, when cleaning the back of the wafer, the preset distance between the back of the wafer 4 and the upper surface of the spray rotating member 5 can be 2 mm to 5 mm, for example but not limited to 3 mm, 3.5 mm, 4 mm. Such a distance can not only avoid contact and scratching between the spray rotating member 5 and the wafer 4, but also make it easy for the sprayed fluid to take away the crystal chips, slag, silicon powder, pollutants, etc. on the wafer without getting stuck between the two. In addition, this distance also prevents the spray rotating member 4 from interfering with the clamping wheel 3.

[0070] At the same time, it can be seen from the figure that the rotation center position of the spray rotating member 5 is aligned with the center of the wafer 4. In this way, during the entire rotation spray cleaning process of the spray rotating member 5, the cleaning liquid can be evenly sprayed onto the back of the wafer 4, and will not tilt from the back of the wafer 4 or even leak, which can improve work efficiency, save cleaning liquid, and improve the utilization rate of the cleaning liquid.

[0071] In an optional embodiment, an oil stone and / or bristles (not shown) may be provided in the central area of ​​the injection rotating member 5, and a cleaning fluid injection hole with an independent liquid supply may be provided in the central area to clean the wafer loading suction cup of the robot to avoid cross contamination of the wafer during loading.

[0072] Figure 4 Shows Figure 3 Schematic bottom view of a wafer and a spray carousel of a wafer cleaning apparatus.

[0073] As can be seen from the figure, the wafer 4 is clamped in place by the clamping wheels 3. Specifically, in this example, the wafer 4 is held in place by four clamping wheels 3. In an optional embodiment, other numbers of clamping wheels may be provided.

[0074] In this example, the spray rotating member 5 is elongated and extends along the entire diameter length of the wafer 4. The hollow arrow in the figure shows its rotation direction, and in this example, it rotates in a clockwise direction. The spray rotating member 5 has two parallel straight edges and two arcuate edges, the two parallel straight edges are symmetrical and equal, the two arcuate edges are symmetrical and equal, and the center of the two arcuate edges is the rotation center of the spray rotating member 5. The spray rotating member 5 itself is an axisymmetric and centrosymmetric shape.

[0075] In the illustrated example, the length of the spray rotating member 5 is such that the two arc-shaped edges are located at the periphery of the wafer edge, so that the spray area can cover the entire back side of the wafer. It is understood that in some embodiments, the length can also be set to such an extent that the two arc-shaped edges overlap with the wafer edge or are located inside the wafer edge, and the spray area covers the entire back side of the wafer by setting the angle and shape of the spray flow. It should be pointed out that this embodiment does not exclude the wafer cleaning device 2 from also having the function of cleaning other surfaces of the wafer.

[0076] As shown in the figure, the center of the wafer 4 is aligned with the center of the spray rotating member 5 (which is also its rotation center). When the two rotate relative to each other, their relative positions and relative movements are the same at each angle, which can provide uniform and consistent cleaning for the back side of the wafer 4. During the cleaning process, the wafer 4 can be kept fixed or rotated under the drive of the clamping wheel according to the needs of different implementation methods. When the wafer is kept fixed, the cleaning of the back side of the wafer can be more consistent.

[0077] Figure 5 Shows Figure 3 Schematic diagram of the side view of the wafer cleaning device in the cleaning state. The driving mechanism, hollow shaft, etc. of the wafer cleaning device are omitted in this figure; these structural arrangements can be referred to Figure 3 Example.

[0078] As can be seen from the figure, the wafer 4 is horizontally clamped in place by the clamping wheel 3, and the spraying rotating member 5 is kept at a certain distance from the back side of the wafer 4. The figure shows the rotation direction of the spraying rotating member 5, and in this example, its rotation direction is such that the end of the spraying rotating member 5 seen on the paper as shown in the figure rotates in the figure toward the right as shown by the horizontal arrow in the figure.

[0079] It can also be seen from the figure that the spray direction of the cleaning fluid in the figure is inclined, and the rotation direction of the spray rotating member 5 is consistent with the spray direction of the cleaning fluid, increasing the relative speed between the water flow and the wafer and increasing the impact force of the liquid flow cleaning. Specifically, as shown in the figure, the spray direction of the spray fluid at this end of the spray rotating member 5 is inclined toward the rotation front of the spray rotating member 5, that is, Figure 5The spray direction of the spray fluid sprayed upward by the spray rotating member 5 is inclined in front of its rotation, as shown by the inclined arrow in the figure. Therefore, when cleaning the back side of the wafer, the rotation of the spray rotating member 5 increases the impact force in the rotation direction of the spray fluid, which helps to improve the cleaning effect.

[0080] In an alternative embodiment, Figure 5 The injection hole 6 of the middle injection rotating member 5 can be in a strip shape, and the injection hole outputs a fan-shaped jet. In order to form a fan-shaped jet, the cleaning liquid can be directly ejected from the strip-shaped injection hole 6, or a fan-shaped nozzle can be installed in the injection hole 6 to form a fan-shaped jet. The fan-shaped nozzle can be used for fluid injection as a fluid mechanical element, which can eject the liquid from the outlet at a certain angle, thereby achieving effects such as uniform spray and large coverage area. By evenly dispersing the liquid spray into a larger area, effective coverage of a larger area of ​​the cleaning liquid can be achieved.

[0081] According to the needs of different embodiments, a fan-shaped two-fluid nozzle is embedded in the injection rotating member 5. Figure 5 The jet fluid sprayed by the middle jet rotating member 5 can be a gas-liquid two-fluid. Accordingly, the jet hole 6, i.e., the water outlet micropore, can be strip-shaped to facilitate the fan-shaped water flow. Bubbles and liquid droplets can be formed by mixing the cleaning liquid and gas and applying them to the back of the wafer to be cleaned. The momentum, impact and shear force of the bubbles and droplets can achieve the purpose of efficient cleaning. This method is efficient, energy-saving, gentle in the cleaning process and easy to operate.

[0082] The gas-liquid dual fluid can be a combination of water and compressed air, which can increase water pressure, increase water flow speed, and form the effect of bubble bursting. This gas-liquid dual fluid is formed by mixing cleaning liquid and gas to form a mixed liquid. The bubbles and droplets in this liquid can interact with each other, thereby generating flow, making the cleaning effect better. In addition, during the cleaning process, bubbles are formed in the liquid, and they are adsorbed and attached to the back of the wafer to be cleaned. The bubbles are injected into the back of the wafer to be cleaned by pressurization, and the bubbles and the dirty surface produce back and forth collisions and continuous compression, which can achieve the purpose of cleaning dirt. In addition, the bubbles and droplets in the cleaning liquid are sheared by the liquid itself, forming a fierce fluid movement, forming a shearing effect on the dirt and film on the back of the wafer to be cleaned, which can achieve the purpose of efficient cleaning.

[0083] In another embodiment, an ultrasonic generator may be provided in the flow path of the cleaning fluid to generate high-frequency vibration in the sprayed cleaning fluid to improve the cleaning effect of small particle pollutants such as silicon powder. The ultrasonic generator uses the cavitation effect, acceleration effect and straight flow effect of ultrasonic waves in the liquid to directly and indirectly act on the liquid and dirt, so that the dirt layer is dispersed, emulsified and peeled off to achieve the cleaning purpose.

[0084] In some embodiments, an ultrasonic generator can be used to generate tiny bubbles in the cleaning liquid, and the cleaning liquid containing such tiny bubbles can be sprayed onto the back of the wafer for cleaning, and the cleaning energy generated by ultrasonic vibration and bubble bursting can be combined to further improve the cleaning effect. Specifically, under the vibration of the ultrasonic wave, the gas in the cleaning liquid is compressed into tiny bubbles; as the bubbles continue to expand, the resistance of the liquid also increases, and when it reaches a certain level, the bubbles will collapse, and the pressure and high temperature generated during the collapse will have a cleaning effect on the cleaning object; in addition, the cleaning liquid contains tiny dissolved gases, and when the bubbles move in the cleaning liquid, gas molecules will accumulate on the surface of the bubbles to form smaller bubbles. At the same time, due to the movement of the liquid around the bubbles, a large number of tiny bubbles are generated, which can enhance the cleaning effect.

[0085] Optionally, a sponge strip (not shown) extending the entire length of the spray rotating member 5 may be provided on the upper surface of the spray rotating member 5. For example, the sponge strip may be provided on the upper surface of the spray rotating member 5. Figure 5 The middle edge is attached to the upper surface of the spray rotating member 5 in a direction perpendicular to the paper surface, which can scrub the back of the wafer to assist in cleaning. It should be noted that the scrubbing here does not necessarily have to be in contact with the back of the wafer. The sponge strip can be set so that the upper surface is close to the back of the wafer but not in contact with it, but can wipe the water film or droplets on the back of the wafer, and can remove the pollutants in the water film or droplets while scrubbing and absorbing them.

[0086] Figure 6 Shows Figure 3 Schematic cross-sectional view of the jetting rotating part of the wafer cleaning device.

[0087] As can be seen from the figure, the cross-sectional profile of the injection rotating member 5 is exemplified as a rectangle. It can be understood that in different embodiments, the cross-sectional profile can be in other required shapes.

[0088] In this example, a first flow channel may be formed inside the injection rotating member 5, and three juxtaposed first flow channels are shown in the figure. Injection holes 6 are distributed on the side of the injection rotating member 5 radially inward and toward the back side of the wafer 4, and the injection holes 6 are used to inject the cleaning fluid. Different first flow channels may be connected to different injection holes 6 respectively. In some embodiments, only one first flow channel may be provided, so that the first flow channel connects all injection holes 6; in some embodiments, other numbers of first flow channels may also be provided, so that different first flow channels are connected to different injection holes 6 respectively.

[0089] It can be seen from the figure that the spray hole 6 is inclined. The inclination direction of the spray hole 6 is the same as the rotation direction of the spray rotating member 5 at this location relative to the wafer, thereby increasing the impact force of the cleaning fluid and improving the cleaning effect.

[0090] In order to further improve the cleaning effect, in some embodiments, a compressed air source or a booster pump may be provided in the flow path of the cleaning fluid to increase the impact force of the sprayed cleaning fluid.

[0091] Figure 7 Schematic diagram of another embodiment of the wafer cleaning device according to the present invention is shown. In this figure, the spray rotating member 5 of the wafer cleaning device cleans the wafer portion blocked by the clamping wheel 3. The driving mechanism, hollow shaft, etc. of the wafer cleaning device are omitted in this figure; these structural arrangements can be referred to Figure 3 Example.

[0092] As shown in the figure, the wafer 4 is horizontally held by three clamping wheels 3, and the jet rotating member 5 of the wafer cleaning device maintains a preset cleaning distance from the back of the wafer 4. As can be seen from the figure, a circle of grooves is formed on the side of the clamping wheel 3, and the circumferential edge of the wafer 4 is stuck in the groove. In this case, it is easy for crystal chips, crystal slag, silicon powder, pollutants, etc. to be deposited at these positions, or some crystal chips, crystal slag, silicon powder, and pollutants cannot be cleaned due to the obstruction of the clamping wheel 3; if these positions cannot be effectively cleaned, it is easy to cause contamination to the wafer.

[0093] In the illustrated embodiment, the injection rotating member 5 is in the shape of a long strip, for example, Figure 4 The shape of the spray rotating member shown in . Outward spray holes 9 can be respectively provided at both ends of the spray rotating member 5. When the spray rotating member 5 is disc-shaped, outward spray holes 9 can be provided at its edge position. The cleaning liquid sprayed from these outward spray holes 9 can directly impact the clamping wheel and the part of the wafer that is clamped or blocked by the clamping wheel, or the sprayed cleaning liquid can impact the clamping wheel and the part of the wafer that is clamped or blocked by the clamping wheel again after returning from the back side of the wafer, so these outward spray holes 9 can be used to independently clean the clamping wheel 3 and the part of the wafer 4 blocked by the clamping wheel 3.

[0094] Figure 8 A schematic diagram of a robot clamping wheel in a wafer cleaning device according to the present invention is shown.

[0095] exist Figure 8 In the left figure, the front view shows the spray hole 10 on the clamping wheel 3, which can be used for self-cleaning and / or detecting the clamping function. The spray hole 10 is located in the groove of the clamping wheel 3 and can spray the cleaning liquid inward along the radial direction of the wafer. Please refer to Fig. 9 When the peripheral edge of the wafer is stuck in the groove, during the cleaning process, the cleaning liquid is sprayed vertically toward the peripheral edge of the wafer from the spray hole 10, which can assist in cleaning the peripheral edge of the wafer. In one embodiment, each clamping wheel can be provided with a spray hole 10.

[0096] In another working environment, after the clamping wheel 3 takes the wafer from the grinding station of the wafer thinning equipment, the spray holes of each group of clamping wheels 3 can spray cleaning liquid, and through hydraulic feedback, it can be determined whether all four groups of clamping wheels are clamped in place. To achieve this purpose, a fluid pressure sensor can be provided at the fluid spray hole 10, and by measuring the hydraulic pressure at the spray hole 10, it can be used to measure the fluid pressure at the fluid spray hole to determine whether the clamping wheel 3 clamps the wafer 4 normally. Fig.10 The normal clamping state and abnormal clamping state of the wafer are shown in the figure. Specifically, a first predetermined value and a second predetermined value of the hydraulic pressure can be preset in the system, wherein the first predetermined value is greater than the second predetermined value. When the fluid pressure is measured to be a higher first predetermined value, it is determined to be normal clamping; when the fluid pressure is measured to be a lower second predetermined value, it is determined to be abnormal clamping. In this way, when it is determined that the wafer 4 is not clamped normally, the action of the clamping wheel 3 can be readjusted to avoid accidents such as broken pieces or wafer falling. For example, in the normal clamping position, the injection hole is blocked, and the fluid pressure can be about 2.5psi; in the abnormal clamping position, the injection hole is not blocked, and the fluid pressure can be about 0.5psi.

[0097] exist Figure 8 In the figure on the right, a cross-sectional view of the clamping wheel 3 taken along AA in the left figure is shown, and the cross-sectional view shows the injection holes and the cleaning liquid flow channel connected thereto. In this example, the transverse injection holes are connected to the longitudinal cleaning liquid flow channel, and the cleaning liquid flow channel runs through the entire clamping wheel 3. The injection holes 10 are used to spray fluid toward the outer peripheral edge of the wafer 4.

[0098] Fig. 9 Shows Figure 8 The direction of water spray at the gripping wheel of the middle manipulator.

[0099] from Fig. 9 It can be seen that there are four clamping wheels around the wafer 4 to clamp the wafer, and the spray holes of each clamping wheel spray toward the center of the wafer along the radial direction of the wafer. The four arrows in the figure show the spray direction of the cleaning liquid. The figure shows that the four clamping wheels are evenly distributed on the periphery of the wafer; in optional embodiments, the number of clamping wheels can be changed, and the distribution position of the clamping wheels on the periphery of the wafer can also be changed.

[0100] Fig.10 Shows Figure 8 The figure above shows the different clamping states of the wafer by the robot clamping wheel. The upper figure shows the normal clamping state of the wafer, and the lower figure shows the abnormal clamping state of the wafer.

[0101] In the above figure, the outer edge of the wafer is clamped in a circle of grooves on the outer periphery of each clamping wheel. At this time, the spray cleaning liquid at the spray hole 10 of each clamping wheel is affected by the obstruction of the outer edge of the wafer, so that the hydraulic pressure at each spray hole 10 increases to a preset first predetermined value, and it can be determined that the wafer is in a normal clamping state.

[0102] In the figure below, the outer edge of the wafer is clamped in the groove of some clamping wheels, and the other part is located outside the groove and stuck on the upper / lower side of the groove. At this time, the hydraulic pressure of the injection hole 10 at some clamping wheels is measured as the second predetermined value, and the hydraulic pressure of the injection hole 10 at some clamping wheels is measured as the first predetermined value, that is, some clamping wheels clamp the outer edge of the wafer, and some clamping wheels do not clamp the outer edge of the wafer. At this time, it can be judged that the wafer is in an abnormal clamping state. In this case, it may cause fragmentation, wafer falling, etc., and it is beneficial to judge this by the injection hydraulic pressure of the injection hole 10.

[0103] The reason for this situation is that after the wafer grinding is completed, the grinding chuck breaks the vacuum (the specific process can be to slightly float the wafer and then insert it into the robot claw). Due to the uneven air pressure in various parts of the chuck, the suspended state of the wafer is prone to tilt, causing one or two of the four clamping wheels to not clamp the wafer in place. The wafer is cleaned and placed in a tilted state, and there is a risk of wafer breakage.

[0104] The present invention also relates to a wafer thinning device 1, such as Figure 1 As shown in , the wafer thinning equipment 1 may include a wafer cleaning device as described in any of the aforementioned embodiments.

[0105] Furthermore, the present invention also relates to a method for performing wafer cleaning in a wafer thinning device 1 using a wafer cleaning device 2 as described in any of the aforementioned embodiments. Specifically, in the exemplary method, four clamping wheels can be used to clamp the wafer, and a manipulator drives it to move to the top of the wafer back cleaning module; the manipulator descends along the Z-axis direction, and the manipulator is used to lower the wafer 4 to a preset distance above the spray rotating member 5, and the back of the wafer can be kept at a distance of about 2mm to 5mm from the upper surface of the spray rotating member; the wafer 4 is kept stationary; the spray rotating member 5 is started to spray the cleaning liquid and rotate in a fixed direction at the same time, and the contaminants are washed down and taken away through the oblique impact of the water flow and the flow of the water film between the wafer and the spray rotating member, so as to achieve the cleaning of the back of the wafer.

[0106] The technical scope of the present invention is not limited to the contents of the above description. Those skilled in the art can make various deformations and modifications to the above implementation without departing from the technical idea of ​​the present invention, and these deformations and modifications should all fall within the scope of the present invention.

Claims

1. A wafer cleaning device for wafer thinning equipment, characterized in that: The gripping wheel (3) of the robot of the wafer thinning equipment holds the wafer (4) in place for wafer cleaning, and the wafer cleaning device is configured to perform non-contact cleaning on the wafer after grinding and thinning, and comprises: A spray rotating member (5), the spray rotating member (5) being used to spray a cleaning fluid onto the back side of a wafer (4) to be cleaned, a first flow channel being formed inside the spray rotating member (5), and spray holes (6) being distributed on the side of the spray rotating member (5) facing the back side of the wafer (4), the spray holes (6) being used to spray the cleaning fluid; the spray rotating member (5) extending along the entire diameter length of the wafer (4), the spray direction of the cleaning fluid being inclined, and the rotation direction of the spray rotating member (5) being consistent with the spray direction of the cleaning fluid; a hollow rotating shaft (7), the hollow rotating shaft (7) being connected to the rotation center of the injection rotating member (5), a second flow channel being formed inside the hollow rotating shaft (7), the first flow channel being connected to the second flow channel; and a driving mechanism (8), the driving mechanism (8) being used to drive the hollow rotating shaft (7) to drive the spray rotating member (5) to rotate while the spray rotating member (5) sprays a cleaning fluid onto the back side of the wafer (4); The clamping wheel (3) is provided with a radially inward fluid injection hole (10), and a fluid pressure sensor is provided at the fluid injection hole (10) for measuring the fluid pressure at the fluid injection hole (10) to determine whether the clamping wheel (3) is clamping the wafer (4) normally: When the fluid pressure is measured to be a higher first predetermined value, it is determined to be normal clamping; When the fluid pressure is measured to be a lower second predetermined value, it is determined to be abnormal clamping.

2. The wafer cleaning device according to claim 1, characterized in that: Outward spray holes (9) are provided at both ends of the spray rotating member (5), and the outward spray holes (9) are used to clean the clamping wheel (3) and the portion of the wafer (4) covered by the clamping wheel (3).

3. The wafer cleaning device according to claim 1, characterized in that: When the wafer is cleaned, the back side of the wafer (4) maintains a preset distance from the upper surface of the spray rotating member (5), and the preset distance is 2 mm to 5 mm.

4. The wafer cleaning device according to claim 1, characterized in that: The flow path of the cleaning fluid is provided with a compressed air source or a booster pump to increase the impact force of the sprayed cleaning fluid.

5. The wafer cleaning device according to claim 1, characterized in that: The flow path of the cleaning fluid is provided with an ultrasonic generator for generating high-frequency vibration in the sprayed cleaning fluid.

6. The wafer cleaning device according to claim 1, characterized in that: The injection hole (6) is strip-shaped, and the injection hole outputs a fan-shaped jet.

7. The wafer cleaning device according to claim 1, characterized in that: The cleaning fluid is a gas-liquid dual fluid.

8. The wafer cleaning device according to claim 1, characterized in that: A sponge strip extending the entire length of the spray rotating member (5) is provided on the upper surface of the spray rotating member (5).

9. The wafer cleaning device according to claim 1, characterized in that: The central area of ​​the spray rotating member (5) is provided with an oil stone and / or bristles, and an independent cleaning fluid spray hole is provided at the central area.

10. A wafer thinning device, characterized in that: The wafer thinning equipment comprises a wafer cleaning device as claimed in any one of claims 1 to 9.

11. A method for cleaning a wafer in a wafer thinning device using the wafer cleaning device as claimed in any one of claims 1 to 9.

12. The method according to claim 11, characterized in that The method comprises the following steps: Using the robot to lower the wafer (4) to a preset distance above the spray rotating member (5); Keeping the wafer (4) stationary; The spray rotating part (5) is started to clean the back side of the wafer.

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