A silicon wafer pretreatment cleaning machine

Abstract

The application belongs to the technical field of silicon wafer cleaning equipment, and particularly relates to a silicon wafer pretreatment cleaning machine, which comprises a cleaning tank, a placing support and a plurality of silicon wafer bodies on the placing support, a turnover mechanism is arranged on the cleaning tank, the turnover mechanism can drive the cleaning structure to translate and rotate, and the cleaning structure comprises a plurality of driving devices and a flushing device. The application realizes simultaneous cleaning of silicon wafers with equal interval distribution, utilizes two kinds of reverse flow vortexes in sequence, enhances shear force through dynamic change of fluid direction, and produces an alternating shear force through switching of water flow direction, so that a two-way stripping effect is generated on pollutants such as particles, organic matters or metal ions on the surface of the silicon wafer. For a silicon wafer with a groove, the tangential force generated by the vortex can destroy the tension balance on the surface of the groove, and switching of the flow direction can make the water flow reciprocate in the groove, so that impurities in the deep part of the groove are pushed out more effectively.

Description

Technical Field

[0001] This invention belongs to the technical field of silicon wafer cleaning equipment, specifically a silicon wafer pretreatment cleaning machine. Background Technology

[0002] Silicon wafers are thin-film semiconductor substrates made primarily of silicon. They are the core carrier for manufacturing various semiconductor devices and integrated circuits. Pure silicon undergoes a series of processing steps to form silicon wafers, which have a smooth and flat surface and excellent semiconductor properties. Various electronic components and circuit structures can be built on them through processes such as photolithography and doping.

[0003] Silicon wafer cleaning is a crucial step in semiconductor manufacturing. Its core purpose is to remove surface impurities to ensure device performance and yield. Impurities originate from the entire silicon wafer manufacturing process and can be categorized into three types: material-native impurities, impurities introduced during processing, and environmental contaminants. Before ultrasonic cleaning, silicon wafers typically require pre-treatment cleaning with water. Due to the presence of large particles on the silicon wafer surface (such as CeO2 particles from SiC and CMP abrasives, typically >1μm in size), if directly subjected to ultrasonic cleaning, the high-speed liquid jet generated by ultrasonic cavitation will push the particles across the silicon wafer surface, forming micro-scratches, especially along the 100° crystal plane. Furthermore, large particles may be pressed into defects on the silicon wafer surface by the shock waves generated by the collapse of cavitation bubbles, leading to deeper contamination.

[0004] In existing silicon wafer pretreatment cleaning machines, the silicon wafers to be cleaned are typically placed on a support for positioning and centralized cleaning. The support is then placed in the cleaning tank, and the wafers are rinsed using a spray nozzle to separate impurities from the wafers. However, because the silicon wafers are spaced horizontally or vertically on the support with relatively small and equal spacing, the front-row wafers can obstruct the water flow during rinsing. This significantly slows down the water flow on the surfaces of the rear-row wafers, resulting in insufficient shear force and difficulty in removing tightly adsorbed particles (such as metal oxides smaller than 50nm), thus reducing cleaning efficiency. Furthermore, some silicon wafers have grooves on their surface, such as those present in dry etching processes in semiconductor manufacturing, which can lead to trench effects. These trenches can also be affected by process parameters, etc. The reason is that the silicon wafer is tilted. During the silicon wafer processing, precise positioning and calibration are required. After the rolling process, a flat groove, namely the positioning groove, is ground on the side of the silicon wafer. Sharp "V"-shaped grooves are also made on the surface and sides of the silicon wafer's edge to form smooth "U"-shaped grooves. This can change the microstructure and mechanical properties of the silicon wafer, enhancing its flexibility without affecting its light absorption capacity. This is helpful for the fabrication of highly flexible monocrystalline silicon solar cells. However, these grooves are also prone to accumulating a large number of impurities. Water flow is also less effective at cleaning the inside of the grooves, making it difficult to remove impurities. If large particles of impurities in the grooves are not cleaned, the cavitation effect of ultrasonic waves in the later stages will push these large particles of impurities to slide on the surface of the silicon wafer, forming micro-scratches, thus affecting the performance and quality of the silicon wafer. Summary of the Invention

[0005] The purpose of this invention is to provide a silicon wafer pretreatment cleaning machine to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A silicon wafer pretreatment cleaning machine includes a cleaning tank, a placement bracket, and multiple silicon wafer bodies on the placement bracket. The placement bracket is located inside the cleaning tank. A flipping mechanism is mounted on the cleaning tank. The flipping mechanism can drive the cleaning structure to translate and rotate. The cleaning structure includes multiple driving devices and rinsing devices. Each driving device and each rinsing device form a group. Each group is equally spaced between two adjacent silicon wafer bodies. Each rinsing device includes a cover, an adjusting plate, and a lid. The lid presses the adjusting plate onto the cover. A first nozzle, a second nozzle, and a third nozzle are arranged radially from the inside to the outside, and the three types of nozzles are equally spaced and arranged around each other. The first nozzle and the third nozzle face the same direction and are biased towards the outer edge of the lid, while the second nozzle is biased towards the center.

[0008] Preferably, the adjusting disc and the cover are rotatably connected. The adjusting disc is provided with multiple sets of adjusting holes at equal intervals. Each set of adjusting holes includes a first adjusting hole, a second adjusting hole, and a third adjusting hole. The adjusting holes in each set are non-radial linearly distributed, and the rotation of the adjusting disc can drive the adjusting holes to connect with the corresponding nozzles one after another.

[0009] Preferably, a first shaft seal is provided between the adjusting disc and the cover.

[0010] Preferably, an installation port is provided at the center of the housing, and a sleeve is threadedly connected to the installation port. A first motor is provided inside the sleeve, and the output end of the first motor passes through the sleeve and is connected to the center of the adjustment disc.

[0011] Preferably, the mounting opening is surrounded by multiple through holes at equal intervals.

[0012] Preferably, the driving device includes an outer shell and a cover. A second motor is disposed in the cavity formed by the outer shell and the cover. The output end of the second motor passes through the cover and is connected to the cover. A second shaft seal is disposed in the annular groove on the cover, and the outer side of the second shaft seal is connected to the interface on the cover.

[0013] Preferably, the cover is further provided with a connection hole, and a water inlet pipe is provided on the connection hole.

[0014] Preferably, the flipping mechanism includes a trough support and a bracket, which are detachably connected. Multiple rotating shafts are linearly arranged at equal intervals on the bracket. The lower end of each rotating shaft is connected to the upper interface of the corresponding outer shell. Each rotating shaft is provided with a gear at its upper end. The gears mesh with a rack, and the rack is located in a groove on the bracket.

[0015] Preferably, a third motor is provided on the upper side of the outer wall of the tank support, and the output end of the third motor is connected to a rotating shaft.

[0016] Preferably, each end of the tank support is provided with a support frame, and the support frame is slidably connected to the upper edge of the cleaning tank. Each support frame is provided with a cylinder, and the output end of the cylinder is provided with a positioning frame, which is installed on the cleaning tank by bolts.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. This invention, by setting up a cleaning tank, a support bracket, a driving device, and a rinsing device, enables simultaneous cleaning of silicon wafers with equal spacing, eliminating the need for individual cleaning and improving cleaning efficiency. Furthermore, through the coordinated operation of the cover, adjusting plate, cap, first adjusting hole, second adjusting hole, first nozzle, second nozzle, first shaft seal, sleeve, and first motor, two opposing vortices can be formed on the silicon wafer. The dynamic change in fluid direction enhances shear force, achieving a better cleaning effect. The switching of water flow direction generates alternating shear force, effectively removing contaminants such as particles, organic matter, or metal ions from the silicon wafer surface. The invention achieves a "bidirectional stripping" effect. For grooved silicon wafers, the tangential force generated by the eddy current disrupts the tension balance on the trench surface. Switching the flow direction allows the water to reciprocate within the trenches, mimicking a "piston effect," more effectively pushing out impurities deep within the trenches. The eddy current formed by the first nozzle gradually diffuses the water flow outwards from the silicon wafer. For trenches with an angle towards the center, the water flow enters more easily, thus carrying away impurities more effectively. Similarly, the eddy current formed by the second nozzle gradually diffuses the water flow towards the center of the silicon wafer. For trenches with an outward angle, the water flow enters more easily, carrying away impurities. Therefore, this invention overcomes the complex trench environment on some silicon wafers, improving cleaning efficiency, wafer performance and quality, reducing defect rates, and saving costs.

[0019] 2. This invention, by setting up a cover, adjusting plate, third adjusting hole, cap, third nozzle, and first shaft seal, can create a vortex near the outer edge of the silicon wafer when cleaning is about to be completed. Because the retention effect of the edge fluid after cleaning the silicon wafer with the cleaning fluid causes the foam generated by the surfactant in the cleaning fluid to accumulate due to buoyancy and be difficult to discharge, forming a "foam dam," if not cleaned in time, when the cleaning fluid at the foam accumulation point evaporates, the metal ions Fe in the contaminants will... 3+ Organic photoresist fragments and other materials can be concentrated, forming visible black or brown marks. The shear force provided by the water flow along the outer edge of the silicon wafer is insufficient to effectively break up the foam. Therefore, a vortex is formed directly near the outer edge of the silicon wafer to compensate for the shear force of the water flow, making the shear force strong enough to break up the foam liquid film. This transforms the edge area from a "weak cleaning area" into a "highly efficient rinsing area," which is especially suitable for edge cleaning of large-size silicon wafers (such as 12-inch wafers) and high-precision processes (such as EUV lithography). It avoids the formation of black marks, requires no subsequent processing, and optimizes the cleaning process.

[0020] 3. This invention, by setting up a cleaning tank, a placement bracket, a tank support, a bracket, a third motor, a support frame, a cylinder, and a positioning frame, allows the cleaning device to be moved between each pair of adjacent silicon wafers after the placement bracket containing the silicon wafer body is placed in for cleaning, using the pushing action of the cylinder. This allows for cleaning of one side, and through the interaction between the rack, gear, and rotating shaft, the other side can be cleaned after one side of the silicon wafer is cleaned. During this process, there is no need for staff to manually change the cleaning surface of the silicon wafer, avoiding contamination of the silicon wafer and making cleaning convenient. Attached Figure Description

[0021] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0023] Figure 2 This is a schematic diagram of the cleaning structure of the present invention;

[0024] Figure 3 This is an exploded structural diagram of the rinsing device of the present invention;

[0025] Figure 4 This is an exploded structural diagram of the driving device of the present invention;

[0026] Figure 5 This is a schematic diagram showing the orientation of the nozzles on the cover of this invention;

[0027] Figure 6 This is an exploded structural diagram of the flipping mechanism of the present invention;

[0028] Figure 7 This is a schematic diagram of the structure of the adjusting disc of the present invention;

[0029] Figure 8 This is a schematic diagram of the structure of the cover of the present invention;

[0030] Figure 9 This is a schematic diagram showing the eddy current direction and the angle of the trench on the silicon wafer towards the center of the circle, as described in this invention.

[0031] Figure 10 This is a schematic diagram showing the eddy current direction and the outward-facing side of the trench angle on the silicon wafer in this invention.

[0032] In the diagram: 1. Cleaning tank; 2. Placement bracket; 3. Silicon wafer body; 4. Tilting mechanism; 41. Tank support; 42. Bracket; 43. Rotating shaft; 44. Gear; 45. Rack; 46. Third motor; 47. Support frame; 48. Cylinder; 49. Positioning frame; 5. Drive device; 51. Outer shell; 52. Cover; 521. Connecting hole; 53. Second motor; 54. Second shaft seal; 55. Water inlet pipe; 6. Flushing device; 61. Cover; 611. Mounting port; 612. Through hole; 62. Adjusting plate; 621. First adjusting hole; 622. Second adjusting hole; 623. Third adjusting hole; 63. Cover; 64. First nozzle; 65. Second nozzle; 66. Third nozzle; 67. First shaft seal; 68. Sleeve; 69. First motor. Detailed Implementation

[0033] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the present invention. However, the present invention can be implemented in different forms and is not limited to the embodiments described in the text. Rather, these embodiments are provided to make the disclosure of the present invention more thorough and complete.

[0034] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly associated with those skilled in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] Example 1

[0037] like Figure 1-10As shown, a silicon wafer pretreatment cleaning machine includes a cleaning tank 1, a placement bracket 2, and multiple silicon wafer bodies 3 on the placement bracket 2. The placement bracket 2 is located inside the cleaning tank 1. A flipping mechanism 4 is mounted on the cleaning tank 1. The flipping mechanism 4 can drive the cleaning structure to translate and rotate. The cleaning structure includes multiple driving devices 5 and rinsing devices 6. Each driving device 5 and each rinsing device 6 form a group. Each group is equally spaced between two adjacent silicon wafer bodies 3. Each rinsing device 6 includes a cover 61, an adjusting plate 62, and a cover 63. The cover 63 presses the adjusting plate 62 onto the cover 61. The cover 63 and the cover 61 are sealed by a sealing ring. The cover 63 is arranged radially from the inside to the outside with a first nozzle 64, a second nozzle 65, and a third nozzle 66, which are equally spaced and arranged around the cover. The first nozzle 64 and the third nozzle 66 face the same direction and are biased towards the outer edge of the cover 63, while the second nozzle 65 is biased towards the center.

[0038] The above structure enables simultaneous cleaning of equally spaced silicon wafers. By utilizing two opposing vortices to enhance shear force through dynamic changes in fluid direction, a better cleaning effect is achieved. The switching of water flow direction generates alternating shear force, producing a "bidirectional peeling" effect on contaminants such as particles, organic matter, or metal ions on the silicon wafer surface. For grooved silicon wafers, the tangential force generated by the vortex disrupts the tension balance on the groove surface, and the switching of flow direction allows the water to reciprocate within the groove, similar to a "piston effect," more effectively pushing out impurities deep within the groove. Compared to traditional unidirectional water flow rinsing, this avoids the problem of only cleaning the area near the groove inlet due to fluid inertia.

[0039] The specific operation is as follows: First, place the silicon wafer body 3 to be cleaned onto the placement bracket 2, then place the placement bracket 2 into the cleaning tank 1. Next, start the cylinder 48. The cylinder 48 moves the rinsing device 6 between each pair of adjacent silicon wafer bodies 3 through the tank bracket 41 and the support 42. Then, introduce the cleaning fluid through the water inlet pipe 55. The cleaning fluid then enters the space formed by the cover 61 and the adjusting plate 62 through the through hole 612. Next, start the first motor 69 to drive the second adjusting hole 622 and the second nozzle 65 on the adjusting plate 62 to connect. Then, the cleaning fluid is sprayed out through the second adjusting hole 622 and the second nozzle 65, forming a vortex on one side of the silicon wafer body 3. The vortex is directed towards the center of the silicon wafer. The diffusion process flushes out impurities in the grooves on the outward side. Then, the first motor 69 drives the adjusting disk 62 to rotate again, disconnecting the second adjusting hole 622 and the second nozzle 65, while connecting the first adjusting hole 621 and the first nozzle 64. This creates a vortex on the silicon wafer body 3, which diffuses outward to the side of the silicon wafer, flushing out impurities in the grooves on the inward side. When the cleaning of one side of the silicon wafer is about to end, the first motor 69 drives the adjusting disk 62 to rotate, disconnecting the first adjusting hole 621 and the first nozzle 64, while connecting the third adjusting hole 623 and the third nozzle 66. This creates a vortex near the outer edge of the silicon wafer body 3, breaking up the foam at the outer edge to prevent black marks from appearing.

[0040] After one side is cleaned, the cylinder 48 drives the rinsing device 6 to leave the gap between the silicon wafer bodies 3. Then, the third motor 46 is started. With the cooperation of the gear 44 and the rack 45, the rotating shaft 43 drives each rinsing device 6 to rotate 180°. Then, the cylinder 48 pushes the rinsing device 6 between the adjacent silicon wafer bodies 3 again, so that the other side of the silicon wafer body 3 can be cleaned. The above cleaning process can be repeated.

[0041] Example 2

[0042] like Figure 2 , 3As shown in Figures 7 and 8, the regulating disk 62 and the cover 61 are rotatably connected. Multiple sets of regulating holes are evenly spaced around the regulating disk 62. Each set includes a first regulating hole 621, a second regulating hole 622, and a third regulating hole 623. The regulating holes in each set are non-radial linearly distributed. Rotation of the regulating disk 62 allows the regulating holes to connect sequentially with their corresponding nozzles. By rotating the regulating disk 62, connections are made between different regulating holes and nozzles, thus forming vortices with different flow directions. A first shaft seal 67 is provided between the regulating disk 62 and the cover 61. By setting a first shaft seal 67, leakage is prevented at the connection between the adjusting disc 62 and the cover 61 when the disc rotates. An installation port 611 is provided at the center of the cover 61. A sleeve 68 is threadedly connected to the installation port 611. A first motor 69 is provided inside the sleeve 68. The output end of the first motor 69 passes through the sleeve 68 and is connected to the center of the adjusting disc 62. The first motor 69 is used to provide driving force for the rotation of the adjusting disc 62. Multiple through holes 612 are provided at equal intervals around the installation port 611. The through holes 612 are used to introduce cleaning fluid into the cover 61.

[0043] Example 3

[0044] like Figure 1 , 4 As shown in Figure 6, the drive device 5 includes a housing 51 and a cover 52. A second motor 53 is installed in the cavity formed by the housing 51 and the cover 52. The output end of the second motor 53 passes through the cover 52 and is connected to the cover 61. A second shaft seal 54 is installed in the annular groove on the cover 52, and the outer side of the second shaft seal 54 is connected to the interface on the cover 61. The cover 52 is also provided with a connection hole 521, and a water inlet pipe 55 is provided on the connection hole 521. The second shaft seal 54 is used to install the cover 61 onto the cover 52 and can prevent the cleaning fluid from leaking at the connection between the cover 61 and the cover 52 when it enters through the water inlet pipe 55. The cleaning fluid can only enter the cover 61 through the through hole 612. The drive device 5 is used to provide driving force for the rotation of the flushing device 6, thereby indirectly controlling the flow rate of water in the vortex.

[0045] The flipping mechanism 4 includes a tank support 41 and a bracket 42, which are detachably connected. Multiple rotating shafts 43 are linearly arranged at equal intervals on the bracket 42. The lower end of each rotating shaft 43 is connected to the upper interface of the corresponding outer casing 51. Each rotating shaft 43 has a gear 44 at its upper end, which meshes with a rack 45. The rack 45 is located in a groove on the bracket 42. Through the cooperation of the rotating shafts 43, rack 45, and gears 44, the multiple rinsing devices 6 and driving devices 5 are flipped synchronously. A third motor 46 is installed on the upper outer wall of the tank support 41. The output end of 46 is connected to a rotating shaft 43. Through the third motor 46, the rotation of the rotating shaft 43 is provided. Both ends of the tank support 41 are provided with support frames 47. The support frames 47 are slidably connected to the upper edge of the cleaning tank 1. Each support frame 47 is provided with a cylinder 48. The output end of the cylinder 48 is provided with a positioning frame 49. The positioning frame 49 is installed on the cleaning tank 1 by bolts. Through the cooperation between the cylinder 48, the positioning frame 49 and the support frame 47, the linear movement of the drive device 5 and the rinsing device 6 in the horizontal direction is realized, so that they can rotate after leaving the gap between the silicon wafer bodies 3.

[0046] The present invention has been described by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvement made by adopting the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, shall be within the protection scope of the present invention.

Claims

1. A silicon wafer pretreatment cleaning machine, comprising a cleaning tank (1), a placement bracket (2), and a plurality of silicon wafer bodies (3) on the placement bracket (2), wherein the placement bracket (2) is located inside the cleaning tank (1), and a flipping mechanism (4) is mounted on the cleaning tank (1), the flipping mechanism (4) being capable of driving the cleaning structure to translate and rotate, characterized in that, The cleaning structure includes multiple driving devices (5) and rinsing devices (6). Each driving device (5) and rinsing device (6) form a group. Each group is equally spaced between two adjacent silicon wafer bodies (3). Each rinsing device (6) includes a cover (61), an adjusting plate (62), and a cover (63). The cover (63) presses the adjusting plate (62) onto the cover (61). The cover (63) is provided with a first nozzle (64), a second nozzle (65), and a third nozzle (66) arranged radially from the inside to the outside. The three types of nozzles are equally spaced and arranged around each other. The first nozzle (64) and the third nozzle (66) face the same direction and are biased towards the outer edge of the cover (63), while the second nozzle (65) is biased towards the center.

2. The silicon wafer pretreatment cleaning machine according to claim 1, characterized in that, The adjustment disc (62) and the cover (61) are rotatably connected. Multiple sets of adjustment holes are arranged at equal intervals around the adjustment disc (62). Each set of adjustment holes includes a first adjustment hole (621), a second adjustment hole (622), and a third adjustment hole (623). The adjustment holes in each set are non-radial linearly distributed, and the rotation of the adjustment disc (62) can drive the adjustment holes to connect with the corresponding nozzles one after another.

3. The silicon wafer pretreatment cleaning machine according to claim 2, characterized in that, A first shaft seal (67) is provided between the adjusting disc (62) and the cover (61).

4. A silicon wafer pretreatment cleaning machine according to claim 3, characterized in that, An installation port (611) is provided at the center of the cover (61). A sleeve (68) is threadedly connected to the installation port (611). A first motor (69) is provided inside the sleeve (68). The output end of the first motor (69) passes through the sleeve (68) and is connected to the center of the adjustment disc (62).

5. A silicon wafer pretreatment cleaning machine according to claim 4, characterized in that, The mounting port (611) is surrounded by a plurality of through holes (612) at equal intervals.

6. A silicon wafer pretreatment cleaning machine according to claim 1, characterized in that, The drive device (5) includes an outer shell (51) and a cover (52). A second motor (53) is provided in the cavity formed by the outer shell (51) and the cover (52). The output end of the second motor (53) passes through the cover (52) and is connected to the cover (61). A second shaft seal (54) is provided in the annular groove on the cover (52), and the outer side of the second shaft seal (54) is connected to the interface on the cover (61).

7. A silicon wafer pretreatment cleaning machine according to claim 6, characterized in that, The cover (52) is also provided with a connection hole (521), and a water inlet pipe (55) is provided on the connection hole (521).

8. A silicon wafer pretreatment cleaning machine according to claim 1, characterized in that, The flipping mechanism (4) includes a trough support (41) and a bracket (42). The trough support (41) and the bracket (42) are detachably connected. Multiple rotating shafts (43) are linearly arranged at equal intervals on the bracket (42). The lower end of each rotating shaft (43) is connected to the upper interface of the corresponding outer shell (51). Each rotating shaft (43) is provided with a gear (44) at its upper end. The gears (44) mesh with a rack (45), and the rack (45) is located in a groove on the bracket (42).

9. A silicon wafer pretreatment cleaning machine according to claim 8, characterized in that, A third motor (46) is provided on the upper side of the outer wall of the groove support (41), and the output end of the third motor (46) is connected to a rotating shaft (43).

10. A silicon wafer pretreatment cleaning machine according to claim 9, characterized in that, Both ends of the tank support (41) are provided with support frames (47), and the support frames (47) are slidably connected to the upper edge of the cleaning tank (1). Each support frame (47) is provided with a cylinder (48), and the output end of the cylinder (48) is provided with a positioning frame (49). The positioning frame (49) is installed on the cleaning tank (1) by bolts.

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