Wafer cleaning device and wafer cleaning method

Abstract

The invention provides a wafer cleaning device and a wafer cleaning method, and belongs to the field of chemical mechanical polishing, the wafer cleaning device comprises a positioning assembly, a blowing mechanism and two brush rollers, the two brush rollers are parallel to each other and have the freedom degrees of moving along the axes of the two brush rollers and rotating around the axes of the two brush rollers, and the positioning assembly is used for positioning the two brush rollers. The two brush rollers are respectively arranged on the upper and lower sides of a wafer to be cleaned; the positioning assembly comprises a plurality of positioning wheels, the positioning wheels are arranged at intervals around the circumference of the to-be-cleaned wafer, the wheel surfaces of the positioning wheels are in running fit with the to-be-cleaned wafer, and positioning grooves capable of axially locking the wafer are formed in the wheel surfaces of the positioning wheels; the blowing mechanism comprises a deionized water nozzle and a chemical liquid nozzle, the blowing direction of the deionized water nozzle faces the upper side face of the wafer, and the blowing direction of the chemical liquid nozzle faces the upper side face of the wafer to be cleaned. Compared with the prior art, the technical problem that the existing wafer cleaning efficiency cannot meet the production requirements of wafers is solved.

Description

Technical Field

[0001] The present invention belongs to the field of chemical mechanical polishing, and more specifically, relates to a wafer cleaning device. The present invention also relates to a wafer cleaning method. Background Art

[0002] In the semiconductor wafer manufacturing process, chemical mechanical polishing (CMP) equipment, as a core processing equipment, undertakes the critical task of global wafer flattening. Specifically, the core process of chemical mechanical polishing (CMP) achieves wafer surface flatness through the synergy of chemical and mechanical effects. First, a polishing slurry containing nanoparticles and chemical reagents is sprayed from the equipment inlet onto the surface of a rotating polishing pad. The polishing head presses the wafer firmly against the polishing pad, and both rotate simultaneously at different speeds, ensuring full contact between the wafer surface and the polishing slurry through pressure and friction. During this process, the chemical components of the polishing slurry soften the surface material of the wafer, while the nanoparticles on the polishing pad gradually remove this softened layer under the action of mechanical friction, ultimately achieving an atomically smooth surface. Throughout the entire process, the equipment monitors the polishing status in real time through sensors. When the preset flatness or thickness target is detected, the equipment automatically stops grinding and raises the polishing head, completing the polishing cycle.

[0003] During the CMP process, contaminants such as abrasive particles, polishing debris, and organic matter accumulate on the wafer surface. If not removed promptly, these contaminants can lead to numerous defects in subsequent processes. Therefore, post-processing is required to clean and dry the polished wafer to provide a smooth and clean wafer surface.

[0004] Currently, the most commonly used cleaning method is to clean wafers in a solution environment, such as immersion in detergent, mechanical scrubbing, and wet chemical cleaning. In existing technologies, post-CMP wafer cleaning is usually completed in two chambers. The first method is to scrub through two brush chambers. The other method is to first enter the first brush chamber for preliminary scrubbing, and then enter the subsequent pencil chamber for further scrubbing. Although these two technologies are widely used, there are also cases where the wafer surface cannot be scrubbed with high precision, stubborn particles exist on the wafer surface, and a large amount of cleaning time is required, which reduces the wafer cleaning efficiency. Summary of the Invention

[0005] The object of the present invention is to provide a wafer cleaning device to solve the technical problem that the existing wafer cleaning efficiency cannot meet the production requirements of wafers.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is to provide a wafer cleaning device, comprising:

[0007] Two brush rollers, the two brush rollers are parallel to each other and have the freedom to move along their own axes and rotate around their own axes, and the two brush rollers are respectively arranged on the upper and lower sides of the wafer to be cleaned;

[0008] The positioning assembly includes a plurality of positioning wheels, each of which is arranged at intervals around the wafer to be cleaned. The wheel surface of the positioning wheel rotates with the wafer to be cleaned, and the wheel surface of the positioning wheel is provided with an annular positioning groove coaxial with the positioning wheel, and the positioning groove can form an axial locking for the wafer;

[0009] The spraying mechanism includes a deionized water nozzle and a chemical liquid nozzle. The deionized water nozzle sprays toward the upper side of the wafer, and the chemical liquid nozzle sprays toward the upper side of the wafer to be cleaned.

[0010] In a feasible implementation, the blowing mechanism also includes a first drying component, which includes a two-fluid nozzle, a chemical liquid pipeline and a first nitrogen pipeline. The two-fluid nozzle is provided with a mixing nozzle, and the mixing nozzle is connected to the chemical liquid pipeline and the first nitrogen pipeline. The blowing direction of the mixing nozzle is toward the upper side of the wafer to be cleaned.

[0011] In a feasible implementation, the blowing mechanism also includes a second drying component, the second drying component includes an isopropyl alcohol nozzle and a second nitrogen nozzle, an isopropyl alcohol pipeline and a second nitrogen pipeline, the isopropyl alcohol nozzle is connected to the isopropyl alcohol pipeline, the second nitrogen nozzle is connected to the second nitrogen pipeline, and the blowing directions of the isopropyl alcohol nozzle and the second nitrogen nozzle are both toward the upper side of the wafer to be cleaned.

[0012] In a feasible implementation, the positioning wheels can move closer to or farther away from each other.

[0013] In a feasible implementation, the diameter of the positioning wheel gradually increases from the middle to the top and bottom ends.

[0014] In a feasible implementation, the brush roller located above the wafer to be cleaned is a first cleaning roller, and the brush roller located below the wafer to be cleaned is a second cleaning roller. The length of the first cleaning roller and the length of the second cleaning roller are both greater than the diameter of the wafer to be cleaned. The outer periphery of the first cleaning roller is provided with a first row of herringbone flow patterns. As the first cleaning roller rotates, the first row of flow patterns guides the cleaning liquid in the middle of the wafer to be cleaned to the outer periphery of the wafer. The outer periphery of the second cleaning roller is provided with a second row of herringbone flow patterns. As the second cleaning roller rotates, the second row of flow patterns guides the cleaning liquid from the edge of the wafer to be cleaned to the middle of the wafer to be cleaned.

[0015] In a feasible implementation, the axes of the two brush rollers are coplanar with the radial line of the wafer to be cleaned.

[0016] In a feasible implementation, the wafer cleaning device also includes a driving mechanism, which includes a multi-jaw chuck and multiple driving shafts. The multi-jaw chuck includes a chuck body and multiple chucks arranged on the chuck body. The chuck body is annular and fixedly installed at a preset workstation. Each of the chucks can approach or move away from the axis of the chuck body. Each of the driving shafts is rotatably provided on each of the chucks, and each of the positioning wheels is coaxially fixed to the top of each of the driving shafts.

[0017] In a feasible implementation, the driving mechanism further includes a driving motor, and the driving motor is used to drive at least one of the driving shafts to rotate.

[0018] Compared with the prior art, the wafer cleaning device provided by the present invention has the following advantages:

[0019] First, when the wafer enters the cleaning station, the wafer positioning wheel clamps the wafer and drives the wafer to rotate. Then, the DIW (deionized water) nozzle sprays a cone of DIW liquid onto the wafer to ensure the integrity of the liquid film on the wafer surface. The two brush rollers now clamp the upper and lower surfaces of the wafer in parallel and rotate synchronously and move axially. The annular grooves of the circumferential positioning wheel are used for axial locking, forming a multi-directional force balance system around the wafer (the brush rollers provide vertical clamping, and the positioning wheel provides horizontal and vertical constraints). Then, the deionized water nozzle and the chemical liquid nozzle spray a pre-set chemical liquid through the tube wall. After the brush rollers are scrubbed, the chemical liquid nozzle stops spraying liquid, and the deionized water nozzle rinses the wafer. The coordinated deionized water spraying of the spray mechanism and the precise spraying of the chemical liquid achieve dynamic double-sided cleaning and zero-displacement stable rotation of the wafer. This solves the problems of easy wafer separation and the inability to clean both sides simultaneously in traditional rotary cleaning, effectively improving the cleaning efficiency of the wafer while avoiding micro-scratches. It is particularly suitable for thin advanced process wafers.

[0020] Secondly, through the integrated design of the chemical liquid / nitrogen dual flow channel of the two-fluid nozzle, the chemical liquid nozzle can achieve surface activation cleaning while the nitrogen nozzle simultaneously generates a directional airflow knife. The two form a micro-region eddy field on the wafer surface (the chemical liquid dissolves the contaminants and the nitrogen strips the residual liquid film), realizing the "cleaning-stripping" in one step. Compared with the step-by-step process, the time is shortened by 50%, and the nitrogen barrier effect can also prevent the wafer from being oxidized by oxygen in the air during the cleaning process, which helps to ensure the surface quality of the wafer. In addition, by adding an isopropyl alcohol nozzle and a second nitrogen nozzle, a step-by-step drying method of isopropyl alcohol replacing deionized water and nitrogen purging is achieved, achieving the technical effect of completely eliminating water marks and achieving residue-free drying, which is conducive to solving the technical problem of dry spots caused by the difficulty in removing micro-droplets on the hydrophilic surface of the wafer.

[0021] Furthermore, the radially adjustable ability of the positioning wheels in the aforementioned structure to move closer or further apart, combined with the wafer clamping process, enables the positioning assembly to adaptively clamp wafers of varying diameters, enabling rapid changeovers and compatibility with multiple wafer sizes. This helps address the inefficient production line changeovers caused by insufficient equipment flexibility. Furthermore, by optimizing the outer shape of the positioning wheels and aligning with the rotational force applied to the wafer, the wafer consistently tends to gravitate toward the center of the positioning wheels during rotation, ensuring more stable wafer clamping and preventing deviation during cleaning and rotation.

[0022] Moreover, through the reverse design of the first row of herringbone flow patterns of the upper brush roller (diverging from the middle to the periphery) and the second row of herringbone flow patterns of the lower brush roller (converging from the edge to the middle) in the above structure, combined with the rotation of the double brush rollers and the rotation of the wafer, directional diversion of the liquid on the upper and lower surfaces of the wafer is achieved, achieving the technical effects of rapid centrifugal drainage on the upper surface to prevent liquid accumulation, centripetal convergence of the liquid film on the lower surface to prevent dry brushing, and improved uniformity of double-sided cleaning, which is conducive to solving the technical problem of different cleaning effects caused by uneven distribution of liquid film on both sides during the brushing process.

[0023] In addition to the above beneficial effects, the setting of the multi-claw chuck can realize the movement and adjustment of each chuck head, and the setting of the drive motor can control the rotation speed of each positioning wheel. The above processes cooperate with each other to realize the synchronous constant speed drive of the wafer at multiple points, so that the wafer rotates smoothly and without slipping during the cleaning process, avoiding local stress concentration at the edge.

[0024] Another object of the present invention is to provide a wafer cleaning method, which is implemented based on the above-mentioned wafer cleaning device and includes the following steps:

[0025] S1. Spray deionized water onto the fixed wafer surface and start rotating the wafer;

[0026] S2. While spraying chemical liquid onto the wafer, two brush rollers clamp the wafer and start rotating, and stop spraying deionized water;

[0027] S3, withdraw the two brush rollers and spray deionized water;

[0028] S4, spraying nitrogen gas and chemical liquid on the wafer around the axis of the wafer;

[0029] S5. Stop spraying nitrogen and chemical liquid and spray deionized water on the wafer;

[0030] S6. Stop spraying deionized water and spray isopropyl alcohol on the wafer;

[0031] S7. After isopropyl alcohol has replaced the deionized water, the isopropyl alcohol spraying flow rate is reduced and nitrogen is sprayed;

[0032] S8. Stop spraying isopropyl alcohol and spray nitrogen gas on the wafer until the wafer is dry.

[0033] Compared with the prior art, the wafer cleaning method of the present invention has all the benefits of the above-mentioned wafer cleaning device. Not only that, through the timed step control of S1 to S8 in the above-mentioned cleaning method (deionized water pre-wetting → chemical liquid brushing → deionized water rinsing → nitrogen / chemical liquid mixed purge → secondary rinsing → IPA replacement → nitrogen gradual drying), combined with the coordinated action of various components of the device, the precise connection of the cleaning-rinsing-drying process and the optimization of fluid action are achieved, achieving the technical effects of efficient staged chemical liquid decontamination, zero-residue replacement of IPA, nitrogen gradient drying without water marks, and improved efficiency of the entire process, which is conducive to solving the technical problems of cross-contamination, drying defects and excessively long cycles caused by unscientific segmentation of traditional cleaning processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without inventive work. In the drawings:

[0035] Figure 1 A schematic diagram of the positional relationship between the brush roller and the wafer in the wafer cleaning device provided by the present invention;

[0036] Figure 2 This is a structural schematic diagram of a positioning component in the wafer cleaning device provided by the present invention;

[0037] Figure 3 This is a structural schematic diagram of the first drying component in the wafer cleaning device provided by the present invention;

[0038] Figure 4 This is a schematic structural diagram of the second drying component in the wafer cleaning device provided by the present invention.

[0039] In the picture:

[0040] 1. Brush roller; 11. First cleaning roller; 111. First row of flow patterns; 12. Second cleaning roller; 121. Second row of flow patterns;

[0041] 2. Positioning assembly; 21. Positioning wheel; 22. Chuck; 23. Chuck body; 24. Drive motor;

[0042] 3. Spraying mechanism; 31. Deionized water nozzle; 32. Chemical liquid nozzle; 33. First drying assembly; 331. Two-fluid nozzle; 332. Chemical liquid pipeline; 333. First nitrogen pipeline; 34. Second drying assembly; 341. Isopropyl alcohol nozzle; 342. Second nitrogen nozzle; 343. Isopropyl alcohol pipeline; 344. Second nitrogen pipeline;

[0043] 4. Wafer to be cleaned. DETAILED DESCRIPTION

[0044] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0045] In the description of the present invention, it should be noted that if terms such as "upper", "lower", "inner" and "back" appear to indicate orientation or positional relationships, they are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the present invention.

[0046] Furthermore, in the description of the present invention, unless otherwise expressly defined, the terms "mounted," "connected," "connect," and "connector" should be interpreted broadly. For example, a connection can be a fixed connection, a removable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0047] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] Please also refer to Figures 1 to 3 The wafer cleaning device provided by the present invention will now be described. The wafer cleaning device includes a positioning assembly, a blowing mechanism, and two brush rollers. The two brush rollers are parallel to each other and have the freedom to move along and rotate around their own axes. The two brush rollers are respectively arranged on the upper and lower sides of the wafer to be cleaned. The positioning assembly includes a plurality of positioning wheels, each of which is arranged at intervals around the wafer to be cleaned. The wheel surface of the positioning wheel rotates in coordination with the wafer to be cleaned, and the wheel surface of the positioning wheel is provided with an annular positioning groove coaxial with the positioning wheel. The positioning groove can form an axial locking for the wafer. The blowing mechanism includes a deionized water nozzle and a chemical liquid nozzle. The deionized water nozzle sprays toward the upper side of the wafer, and the chemical liquid nozzle sprays toward the upper side of the wafer to be cleaned.

[0049] During the specific implementation of the above embodiment, after the wafer enters the cleaning station, the positioning wheel of the wafer clamps the wafer and drives the wafer to rotate, and then the DIW (deionized water) nozzle sprays a conical DIW liquid onto the wafer to ensure the integrity of the liquid film on the wafer surface. At this time, the two brush rollers clamp the upper and lower surfaces of the wafer in parallel, and rotate and move axially synchronously, and cooperate with the axial locking of the annular groove of the circumferential positioning wheel to form a multi-directional force balance system around the wafer (the brush roller provides vertical clamping, and the positioning wheel provides horizontal and vertical constraints); and then the wafer is removed through the tube wall. The sub-water nozzle and the chemical liquid nozzle spray the pre-set chemical liquid. After the brush roller finishes brushing, it retracts and the chemical liquid nozzle stops spraying the liquid. The deionized water nozzle rinses the wafer. With the coordination of the deionized water spraying of the blowing mechanism and the precise spraying of the chemical liquid mentioned above, dynamic double-sided cleaning and zero-displacement stable rotation of the wafer are achieved; the problems of easy wafer shedding and inability to clean both sides at the same time in traditional rotary cleaning are solved, the cleaning efficiency of the wafer is effectively improved, while avoiding micro-scratches, and it is particularly suitable for advanced process wafers with lower thickness.

[0050] Based on the above embodiment, in a feasible embodiment, the spray mechanism also includes a first drying component, which includes a two-fluid nozzle, a chemical liquid pipeline, and a first nitrogen pipeline. The two-fluid nozzle is provided with a mixing nozzle, which is connected to the chemical liquid pipeline and the first nitrogen pipeline. The mixing nozzle is sprayed toward the upper side of the wafer to be cleaned. Compared with the existing technology, this embodiment uses an integrated chemical liquid / nitrogen dual-flow channel design of the two-fluid nozzle, so that the chemical liquid nozzle can achieve surface activation cleaning while the nitrogen nozzle simultaneously generates a directional airflow knife. The two form a micro-region eddy flow field on the wafer surface (the chemical liquid dissolves contaminants and the nitrogen gas strips the residual liquid film), achieving a one-step "cleaning-stripping" process. Compared with the step-by-step process, the time is shortened by 50%, and the nitrogen barrier effect can also prevent the wafer from being oxidized by oxygen in the air during the cleaning process, helping to ensure the surface quality of the wafer. Furthermore, in addition to the first drying assembly, the spray mechanism also includes a second drying assembly. The second drying assembly includes an isopropyl alcohol nozzle, a second nitrogen nozzle, an isopropyl alcohol line, and a second nitrogen line. The isopropyl alcohol nozzle is connected to the isopropyl alcohol line, and the second nitrogen nozzle is connected to the second nitrogen line. The isopropyl alcohol nozzle and the second nitrogen nozzle both spray toward the upper side of the wafer to be cleaned. In a specific implementation, the addition of the isopropyl alcohol nozzle and the second nitrogen nozzle achieves a stepped drying process, replacing deionized water with isopropyl alcohol and purging with nitrogen. This achieves the technical effect of completely eliminating water marks and achieving residue-free drying, which helps solve the technical problem of drying spots caused by the difficulty in removing microdroplets on the hydrophilic surface of the wafer.

[0051] In addition to the above feasible embodiments, in order to increase the adaptability to wafers of different sizes, each positioning wheel can move closer to or farther away from each other. Preferably, in order to drive each positioning wheel to move, the wafer cleaning device also includes a drive mechanism, the drive mechanism including a multi-jaw chuck and multiple drive shafts, the multi-jaw chuck including a chuck body and multiple chucks provided on the chuck body, the chuck body being annular and fixedly mounted at a preset station, each chuck being able to move closer to or farther away from the axis of the chuck body, each drive shaft being rotatably provided on each chuck, and each positioning wheel being coaxially fixed to the top of each drive shaft. Similarly, in order to drive each positioning wheel to rotate, the drive mechanism also includes a drive motor, which is used to drive at least one drive shaft to rotate. Compared with the prior art, the present invention realizes the adaptive clamping of wafers of different diameters by the radial adjustment capability of each positioning wheel in the above structure that can move closer to or farther away from each other in conjunction with the wafer clamping process, achieving the technical effect of rapid changeover and compatibility of multiple-sized wafers with one machine, which is conducive to solving the technical problem of low efficiency of production line changeover caused by insufficient equipment flexibility.

[0052] In addition, by setting up the multi-claw chuck, the movement and adjustment of each chuck head can be realized, and the setting up of the drive motor can control the rotation speed of each positioning wheel. The above processes cooperate with each other to realize the synchronous constant speed drive of the wafer at multiple points, so that the wafer rotates smoothly and does not slip during the cleaning process, avoiding local stress concentration at the edge. It should be noted that the number of claws in the multi-claw chuck in this embodiment is four, and its specific structural form is shown in Figure .... The setting up of the drive motor can control the rotation speed of each positioning wheel. The above processes cooperate with each other. More specifically, the drive motor drives each positioning wheel or one of the positioning wheels to rotate through a retractable universal shaft, please refer to Figure ..., to realize the synchronous constant speed drive of the wafer at multiple points, so that the wafer rotates smoothly and does not slip during the cleaning process, avoiding local stress concentration at the edge.

[0053] In a feasible implementation, the diameter of the positioning wheel gradually increases from the middle to the top and bottom ends. By optimizing the outer peripheral shape of the positioning wheel and cooperating with the rotation process of the wafer under force, the wafer always tends to move closer to the middle of the positioning wheel during rotation, thereby being able to clamp the wafer more stably and prevent the wafer from deviating during cleaning and rotation.

[0054] In a feasible implementation, the brush roller located above the wafer to be cleaned is the first cleaning roller, and the brush roller located below the wafer to be cleaned is the second cleaning roller. The length of the first cleaning roller and the length of the second cleaning roller are both greater than the diameter of the wafer to be cleaned. The outer periphery of the first cleaning roller is provided with a first row of herringbone flow patterns. As the first cleaning roller rotates, the first row of flow patterns guides the cleaning liquid in the middle of the wafer to be cleaned to the outer periphery of the wafer. The outer periphery of the second cleaning roller is provided with a second row of herringbone flow patterns. As the second cleaning roller rotates, the second row of flow patterns guides the cleaning liquid from the edge of the wafer to be cleaned to the middle of the wafer to be cleaned. In the above structure, the reverse design of the first row of herringbone flow patterns of the upper brush roller (diverging from the middle to the periphery) and the second row of herringbone flow patterns of the lower brush roller (converging from the edge to the middle), combined with the rotation of the double brush rollers and the rotation of the wafer, realizes the directional diversion of liquid on the upper and lower surfaces of the wafer, and achieves the technical effects of rapid centrifugal drainage on the upper surface to prevent liquid accumulation, centripetal convergence of the liquid film on the lower surface to prevent dry brushing, and improved uniformity of double-sided cleaning. Double-sided cleaning of the wafer can be achieved without turning the wafer over, which is conducive to solving the technical problem of different cleaning effects caused by uneven distribution of liquid film on both sides during the brushing process.

[0055] In a feasible implementation method, the axes of the two brush rollers are coplanar with the radial line of the wafer to be cleaned. Combined with the rotation and axial movement of the brush rollers, the linear full coverage of the radial area of ​​the wafer by the movement trajectory of the brush bristles is achieved, achieving the technical effect of eliminating cleaning blind spots and ensuring consistent cleanliness between the edge and the center, which is conducive to solving the technical problem of incomplete cleaning of the edge area when the brush rollers are parallel to the wafer.

[0056] In summary, compared with the prior art, the wafer cleaning device of the present invention, in its specific implementation process, uses two axially movable and self-rotating parallel brush rollers to clamp the wafer for double-sided brushing, cooperates with the annular groove of the circumferentially adjustable positioning wheel to axially lock the wafer, the herringbone flow patterns of the upper and lower brush rollers to reversely guide the liquid film, and the multi-claw chuck drives the positioning wheel to adaptively clamp wafers of different sizes. At the same time, combined with the timed cleaning process of deionized water / chemical liquid step-by-step spraying, nitrogen-chemical liquid mixed pre-drying, and isopropyl alcohol-nitrogen step replacement drying, it realizes efficient double-sided wafer cleaning without blind spots, zero rotation offset to prevent damage, uniform liquid film coverage to prevent dry brushing, edge stress dispersion to prevent hidden cracks, multi-size rapid mold change and zero water mark drying with integrated precision control, achieving the technical effects of doubling the cleaning efficiency, improving the yield and drying without residue, and completely solving the technical problems of low efficiency of traditional single-sided cleaning, scratches caused by unstable wafer fixation, poor cleaning effect due to uneven liquid film distribution, high risk of edge stress concentration and fragmentation, and unscientific segmentation of the drying process to produce water marks.

[0057] Based on the same inventive concept, another object of the present invention is to provide a wafer cleaning method, which is implemented based on the above-mentioned wafer cleaning device and includes the following steps:

[0058] S1. Spray deionized water onto the fixed wafer surface and start rotating the wafer;

[0059] S2. While spraying chemical liquid onto the wafer, two brush rollers clamp the wafer and start rotating, and stop spraying deionized water;

[0060] S3, withdraw the two brush rollers and spray deionized water;

[0061] S4, spraying nitrogen gas and chemical liquid on the wafer around the axis of the wafer;

[0062] S5. Stop spraying nitrogen and chemical liquid and spray deionized water on the wafer;

[0063] S6. Stop spraying deionized water and spray isopropyl alcohol on the wafer;

[0064] S7. After isopropyl alcohol has replaced the deionized water, the isopropyl alcohol spraying flow rate is reduced and nitrogen is sprayed;

[0065] S8. Stop spraying isopropyl alcohol and spray nitrogen gas on the wafer until the wafer is dry.

[0066] Specifically, in the specific implementation process of the above embodiment, the wafer after polishing and grinding enters the cleaning station and is clamped by the positioning wheel. The DIW nozzle sprays DIW liquid onto the wafer according to the set flow rate (the flow rate is generally 1000ml / min~1500ml / min), and the wafer starts to rotate (the speed is 200rpm~300rpm). After 5s~10s, the brush roller enters the working state from the Home position and starts to clamp the wafer. The clamping distance is 0.5mm~1.5mm. At this time, the brush roller speed is 100rpm~200rpm, and the wafer speed is 150rpm~300rpm. The duration is 20s~40s. The chemical liquid nozzle sprays a specific flow rate of chemical liquid (the flow rate is generally 800ml / min~1500ml / min). At the same time, the DIW nozzle is closed during the process of the brush roller clamping the wafer. After the process is completed, the brush roller returns to the Home position, and the DIW nozzle opens to spray DIW liquid onto the wafer (the flow rate is generally 1500ml / min~2000ml / min). The wafer rotation speed is maintained at 200rpm~300rpm, and the duration is 5s~10s.

[0067] After the wafer is initially brushed, the DIW liquid sprayed out keeps the wafer with a complete liquid film (the flow rate is generally 500ml / min~800ml / min). The process lasts for 5s~10s. After the end, the DIW (deionized water) nozzle returns to the home position, and the two-fluid nozzle starts to purge from the edge of the wafer to the other edge and sprays the two-fluid liquid. The two-fluid is formed by N2 and chemical liquid (generally SC1) through the two-fluid nozzle. The N2 flow rate is generally (30L / min~50L / min), and the chemical liquid flow rate is generally 150ml / min~200ml / min. Set the wafer center as the origin, and the position of the two-fluid nozzle just entering the wafer is set to 145mm. Then the swing arm of the two-fluid nozzle will run from 145mm of the wafer to -145mm at a certain speed for purging and then return to the 145mm position to end the operation. The swing arm process can be divided into any number of sections according to process requirements, and the swing arm speed, two-fluid flow rate and wafer rotation speed can be adjusted separately for each section.

[0068] After the two-fluid nozzle returns to the Home position, the deionized water nozzle sprays DIW liquid toward the center of the wafer again. After 5s to 10s, the deionized water nozzle returns to the Home position, and the isopropyl alcohol nozzle and the second nitrogen nozzle spray IPA liquid toward the center of the wafer. The IPA liquid flow rate is 200ml / min to 300ml / min, the wafer rotation speed is 500rpm, and the duration is 5s to 10s. During this process, it is necessary to ensure that IPA fully replaces DIW to form a complete IPA liquid film. This can reduce particle contamination of the wafer during the drying process. After the end, the IPA flow rate is reduced to 200ml / min, and the N2 pipeline is opened (the flow rate is generally 50L / min to 25L / min). At the same time, the swing arm begins to move from the center of the wafer toward the 145mm direction for purge. During this process, the IPA flow rate gradually decreases to 150ml / min, the wafer rotation speed gradually decreases to 400rpm, and the N2 flow rate gradually decreases to 20L / min. At the end of this process, the IPA pipeline is closed first, and after the N2 pipeline runs to the end position of the IPA pipeline (145mm), the isopropyl alcohol nozzle and the nitrogen nozzle of the second nitrogen nozzle return to the center of the wafer to spray N2. The flow rate is generally 30L / min~50L / min, and the duration is 25s~30s. This process can ensure that the wafer is washed and dried, and will not bring other particle contamination due to insufficient IPA drying.

[0069] Compared with the prior art, the wafer cleaning method of the present invention has all the benefits of the above-mentioned wafer cleaning device. Not only that, through the timed step control of S1 to S8 in the above-mentioned cleaning method (deionized water pre-wetting → chemical liquid brushing → deionized water rinsing → nitrogen / chemical liquid mixed purge → secondary rinsing → IPA replacement → nitrogen gradual drying), combined with the coordinated action of various components of the device, the precise connection of the cleaning-rinsing-drying process and the optimization of fluid action are achieved, achieving the technical effects of efficient staged chemical liquid decontamination, zero-residue replacement of IPA, nitrogen gradient drying without water marks, and improved efficiency of the entire process, which is conducive to solving the technical problems of cross-contamination, drying defects and excessively long cycles caused by unscientific segmentation of traditional cleaning processes.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wafer cleaning device, characterized in that: include: Two brush rollers, the two brush rollers are parallel to each other and have the freedom to move along their own axes and rotate around their own axes, and the two brush rollers are respectively arranged on the upper and lower sides of the wafer to be cleaned; The positioning assembly includes a plurality of positioning wheels, each of which is arranged at intervals around the wafer to be cleaned. The wheel surface of the positioning wheel rotates with the wafer to be cleaned, and the wheel surface of the positioning wheel is provided with an annular positioning groove coaxial with the positioning wheel, and the positioning groove can form an axial locking for the wafer; The spraying mechanism includes a deionized water nozzle and a chemical liquid nozzle. The deionized water nozzle sprays toward the upper side of the wafer, and the chemical liquid nozzle sprays toward the upper side of the wafer to be cleaned.

2. The wafer cleaning device according to claim 1, wherein: The blowing mechanism also includes a first drying component, which includes a two-fluid nozzle, a chemical liquid pipeline and a first nitrogen pipeline. The two-fluid nozzle is provided with a mixing nozzle, and the mixing nozzle is connected to the chemical liquid pipeline and the first nitrogen pipeline. The blowing direction of the mixing nozzle is toward the upper side of the wafer to be cleaned.

3. The wafer cleaning device according to claim 2, wherein: The blowing mechanism also includes a second drying component, which includes an isopropyl alcohol nozzle and a second nitrogen nozzle, an isopropyl alcohol pipeline and a second nitrogen pipeline. The isopropyl alcohol nozzle is connected to the isopropyl alcohol pipeline, and the second nitrogen nozzle is connected to the second nitrogen pipeline. The blowing directions of the isopropyl alcohol nozzle and the second nitrogen nozzle are both toward the upper side of the wafer to be cleaned.

4. The wafer cleaning device according to claim 1, wherein: The positioning wheels can move closer to or farther away from each other.

5. The wafer cleaning device according to claim 4, wherein: The diameter of the positioning wheel gradually increases from the middle to the top and bottom ends.

6. The wafer cleaning device according to claim 5, wherein: The brush roller located above the wafer to be cleaned is the first cleaning roller, and the brush roller located below the wafer to be cleaned is the second cleaning roller. The length of the first cleaning roller and the length of the second cleaning roller are both greater than the diameter of the wafer to be cleaned. The outer periphery of the first cleaning roller is provided with a first row of herringbone-shaped flow patterns. As the first cleaning roller rotates, the first row of flow patterns guides the cleaning liquid in the middle of the wafer to be cleaned to the outer periphery of the wafer. The outer periphery of the second cleaning roller is provided with a second row of herringbone-shaped flow patterns. As the second cleaning roller rotates, the second row of flow patterns guides the cleaning liquid from the edge of the wafer to be cleaned to the middle of the wafer to be cleaned.

7. The wafer cleaning device according to claim 1, wherein: The axes of the two brush rollers are coplanar with the radial line of the wafer to be cleaned.

8. The wafer cleaning device according to claim 4, wherein: The wafer cleaning device also includes a driving mechanism, which includes a multi-jaw chuck and multiple driving shafts. The multi-jaw chuck includes a chuck body and multiple chucks arranged on the chuck body. The chuck body is annular and fixedly installed at a preset workstation. Each of the chucks can approach or move away from the axis of the chuck body. Each of the driving shafts is rotatably provided on each of the chucks, and each of the positioning wheels is coaxially fixed to the top of each of the driving shafts.

9. The wafer cleaning device according to claim 8, wherein: The driving mechanism further comprises a driving motor, which is arranged below the multi-jaw chuck and is used to drive at least one of the driving shafts to rotate.

10. A method for cleaning a wafer, characterized in that: The wafer cleaning method is implemented based on the wafer cleaning device according to claim 3 and includes the following steps: S1. Spray deionized water onto the fixed wafer surface and start rotating the wafer; S2. While spraying chemical liquid onto the wafer, two brush rollers clamp the wafer and start rotating, and stop spraying deionized water; S3, withdraw the two brush rollers and spray deionized water; S4, spraying nitrogen gas and chemical liquid on the wafer around the axis of the wafer; S5. Stop spraying nitrogen and chemical liquid and spray deionized water on the wafer; S6. Stop spraying deionized water and spray isopropyl alcohol on the wafer; S7. After isopropyl alcohol has replaced the deionized water, the isopropyl alcohol spraying flow rate is reduced and nitrogen is sprayed; S8. Stop spraying isopropyl alcohol and spray nitrogen gas on the wafer until the wafer is dry.

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