Drain mechanism for wafer cleaning tank

Abstract

This invention discloses a drainage mechanism for a wafer cleaning tank, used to discharge cleaning fluid from the tank. The drainage mechanism includes an overflow tank inserted into the cleaning tank, a lifting drive assembly for driving the overflow tank to move up and down, a waste fluid collection tank, and a drainage pipe connecting the overflow tank and the waste fluid collection tank. An overflow port is formed on the overflow tank. As the lifting drive assembly drives the overflow tank downwards, the cleaning fluid overflows from the overflow port and is collected in the waste fluid collection tank. The cleaning fluid level is flush with the overflow port and gradually decreases. This invention abandons the conventional method of using gravity to control the water level descent. By adopting an overflow method and controlling the overflow height, it achieves precise control of the descent speed of the cleaning fluid level, ensuring the stability of the cleaning fluid level and effectively improving the drying effect on wafers based on the Marangoni principle.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor processing, and specifically relates to a draining mechanism for a wafer cleaning tank. Background Technology

[0002] In the semiconductor industry, after the wet wafer process, it is usually necessary to clean and dry the residual chemical agents on the wafer surface to ensure that the chemical agents on the wafer surface are cleaned and the number of particles meets the requirements of subsequent processes after drying.

[0003] Currently, the traditional cleaning process involves: (1) soaking; (2) drying. In this process, the wafer is loaded onto a carrier, and the carrier is immersed in a cleaning tank containing cleaning fluid to complete the soaking. During drying, as the cleaning fluid is drained from the tank, the liquid level drops, gradually exposing the wafer surface. The Marangoni principle is then used to dry the exposed portion of the wafer. Specifically, isopropyl alcohol (IPA) is sprayed into the cleaning tank to form an IPA liquid film on the surface of the cleaning fluid, creating the Marangoni effect and thus drying the wafer surface.

[0004] However, in actual production, when the cleaning liquid is discharged from the cleaning tank, it is usually discharged through the bottom drain port. Based on the gravity of the cleaning liquid itself, the liquid is discharged from the cleaning tank. This method is difficult to control the rate of liquid level change, and outside air can easily enter the cleaning tank through the drain port and generate rising bubbles, which can easily cause fluctuations in the surface of the cleaning liquid. This can damage the formed IPA liquid film, causing the Marangoni principle to fail. This greatly increases the probability that the cleaning liquid will climb up the wafer surface and remain, resulting in poor drying effect on the wafer surface. Summary of the Invention

[0005] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a brand-new drainage mechanism for wafer cleaning tanks.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0007] A drainage mechanism for a wafer cleaning tank is provided for discharging cleaning fluid from the cleaning tank. The drainage mechanism includes an overflow tank inserted into the cleaning tank, a lifting drive assembly for driving the overflow tank to move up and down, a waste fluid collection tank, and a drainage pipe connecting the overflow tank and the waste fluid collection tank. An overflow port is formed on the overflow tank. As the lifting drive assembly drives the overflow tank to move downward, the cleaning fluid overflows from the overflow port and is collected in the waste fluid collection tank. The cleaning fluid level is flush with the overflow port and gradually decreases.

[0008] According to a specific embodiment and preferred aspect of this utility model, the overflow port includes a plurality of overflow notches spaced apart along the width direction of the cleaning tank. The cleaning fluid is diverted through the plurality of overflow notches and enters the overflow tank. Here, based on the diversion of the fluid by the plurality of overflow notches and the formation of a buffer, the smoothness of the overflow discharge of the cleaning fluid is effectively improved, further reducing the fluctuations caused by the discharge and ensuring the stability of the Marangoni effect.

[0009] Preferably, each overflow notch has rounded corners at both ends along the overflow direction. This makes the cleaning fluid overflow more gradual.

[0010] Preferably, the overflow tank includes a first side plate and a second side plate spaced apart from the inside to the outside along the thickness direction of the cleaning tank, an end plate connecting the opposite sides of the first and second side plates, and a bottom plate connecting the bottoms of the first and second side plates. The drain pipe is connected between the bottom plate and the waste liquid collection tank. Here, the structure is simple and easy to assemble and implement.

[0011] Specifically, the first side plate bends from the top toward the second side plate to form a first bend, and the second side plate bends from the top toward the first side plate to form a second bend located above the first bend, wherein an overflow port is formed between the first bend and the second bend. Both the first bend and the second bend are horizontally extended.

[0012] Preferably, a plurality of diversion sections are formed on the first bend, which are spaced apart along the width direction of the cleaning tank, wherein an overflow gap is formed between each two adjacent diversion sections.

[0013] Specifically, multiple diversion sections are vertically arranged at the end of the first bend near the second side plate. Here, the overflow position is close to the side wall of the overflow tank to facilitate the formation of an IPA liquid film on the cleaning liquid surface that meets the area requirements.

[0014] Preferably, the base plate extends at an angle both vertically and horizontally, and the connection point of the drain pipe on the base plate is located at the lowest end of the base plate. This facilitates the cleaning fluid to be discharged under its own weight within the overflow tank.

[0015] Preferably, the drainage pipeline includes multiple pipes connected sequentially from top to bottom, wherein the diameter of the multiple pipes increases progressively from top to bottom. This facilitates the discharge and collection of the cleaning fluid.

[0016] Furthermore, the uppermost pipeline is connected to the base plate via a connecting block, and the lifting drive assembly includes a telescopic rod connected to the connecting block and capable of extending and retracting vertically. This facilitates the matching of the extension and retraction of the drainage pipeline with the lifting and lowering of the overflow tank.

[0017] Due to the implementation of the above technical solution, this utility model has the following advantages compared with the prior art:

[0018] In existing technologies, cleaning tanks typically discharge cleaning fluid through a bottom drain port, relying on gravity to expel the fluid. This method is difficult to control in terms of the rate of fluid level change, and outside air can easily enter the tank through the drain port, generating rising bubbles that can cause fluctuations in the cleaning fluid surface. This disrupts the formed IPA film, rendering the Marangoni principle ineffective and significantly increasing the probability of cleaning fluid climbing up the wafer surface and remaining there, resulting in poor wafer surface drying. This application addresses the shortcomings and defects of existing technologies by comprehensively designing the drainage mechanism for wafer cleaning tanks. With this drainage mechanism, when cleaning fluid needs to be discharged from the tank, a lifting drive component drives the overflow tank to be inserted into the tank from top to bottom, making the overflow port level with the cleaning fluid surface. As the overflow tank continues to move downwards, the cleaning fluid overflows from the overflow port and is collected in the waste fluid collection tank. The cleaning fluid surface remains level with the overflow port and gradually descends, achieving precise control over the rate of descent of the cleaning fluid surface. Therefore, compared with the prior art, this utility model abandons the conventional method of using the gravity of water as a driving force to control the descent of the water surface. By adopting an overflow method and controlling the overflow height, it achieves precise control of the descent speed of the cleaning liquid surface, ensuring the stability of the cleaning liquid surface and effectively improving the drying effect of wafers based on the Marangoni principle. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the installation structure of the draining mechanism of this utility model on the wafer cleaning tank (partially omitted);

[0020] Figure 2 This is a front view schematic diagram of the drainage mechanism of this utility model;

[0021] Figure 3 for Figure 2 Enlarged rear view of the overflow channel;

[0022] Figure 4 for Figure 2 Schematic diagram of the AA section;

[0023] Figure 5 for Figure 3 Enlarged schematic diagram of the structure at point B;

[0024] C, cleaning tank;

[0025] 1. Overflow channel; k. Overflow outlet; k0. Overflow notch; 11. First side plate; b1. First bend; b10. Diversion section; 12. Second side plate; b2. Second bend; 13. End plate; 14. Bottom plate;

[0026] 2. Waste liquid collection tank;

[0027] 3. Drainage pipeline; 30. Pipeline; 300. Connecting block;

[0028] 4. Lifting drive assembly; 40. Telescopic mast. Detailed Implementation

[0029] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0030] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0033] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0034] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0035] like Figures 1 to 5 As shown, the drainage mechanism for the wafer cleaning tank in this embodiment is used to drain the cleaning liquid in the cleaning tank C. The drainage mechanism includes an overflow tank 1, a waste liquid collection tank 2, a drainage pipe 3, and a lifting drive assembly 4.

[0036] Specifically, the overflow tank 1 is inserted into the cleaning tank C, and an overflow port k is formed on the overflow tank 1; the lifting drive assembly 4 drives the overflow tank 1 to move up and down; the drain pipe 3 connects the overflow tank 1 and the waste liquid collection tank 2. As the lifting drive assembly 4 drives the overflow tank 1 to move downward, the cleaning liquid overflows from the overflow port k and is collected in the waste liquid collection tank 2. The cleaning liquid level is flush with the overflow port k and gradually decreases.

[0037] In this example, the overflow tank 1 includes a first side plate 11 and a second side plate 12 spaced apart from the inside to the outside along the thickness direction of the cleaning tank C, an end plate 13 connecting the opposite sides of the first side plate 11 and the second side plate 12, and a bottom plate 14 connecting the bottoms of the first side plate 11 and the second side plate 12. The drain pipe 3 is connected between the bottom plate 14 and the waste liquid collection tank 2. Here, the structure is simple and easy to assemble and implement.

[0038] Specifically, the first side plate 11 is bent from the top toward the second side plate 12 to form a first bend b1, and the second side plate 12 is bent from the top toward the first side plate 11 to form a second bend b2 located above the first bend b1, wherein an overflow port k is formed between the first bend b1 and the second bend b2. Both the first bend b1 and the second bend b2 are horizontally extended; the bottom plate 14 is inclined vertically, and the connection point of the drain pipe 3 on the bottom plate 14 is located at the lowest end of the bottom plate 14.

[0039] For ease of implementation, the overflow port k includes multiple overflow notches k0 spaced apart along the width direction of the cleaning tank C. The cleaning fluid is diverted through the multiple overflow notches k0 and enters the overflow tank 1. Here, based on the diversion of the multiple overflow notches and the formation of a buffer, the smoothness of the overflow discharge of the cleaning fluid is effectively improved, further reducing the fluctuations caused by the discharge and ensuring the stability of the Marangoni effect.

[0040] At the same time, each overflow notch k0 has rounded corners at both ends along the overflow direction. Here, the overflow of cleaning fluid is more gradual.

[0041] In some specific embodiments, a plurality of diversion sections b10 are formed on the first bend b1, spaced apart along the width direction of the cleaning tank C. These diversion sections b10 are vertically disposed on the first bend b1 near the end of the second side plate 12, and an overflow notch k0 is formed between every two adjacent diversion sections b10. Here, the overflow position is made close to the sidewall of the overflow tank to facilitate the formation of an IPA liquid film on the cleaning liquid surface that meets the area requirements.

[0042] In this example, the waste liquid collection tank 2 is located below the cleaning tank C. The drainage pipe 3 includes multiple pipes 30 connected sequentially from top to bottom, with the diameter of the multiple pipes 30 increasing progressively from top to bottom. The uppermost pipe 30 is connected to the bottom plate 14 through a connecting block 300 that forms an internal flow channel, and the lowermost pipe 30 is connected to the waste liquid collection tank 2. This facilitates the discharge and collection of the cleaning liquid.

[0043] Furthermore, the lifting drive assembly 4 includes a telescopic rod 40 connected to the connecting block 300 and capable of telescopic movement along the vertical direction. This facilitates matching the telescopic movement of the drain pipe with the lifting movement of the overflow tank.

[0044] In summary, with this drainage mechanism, when the cleaning fluid in the cleaning tank needs to be drained, the overflow tank is driven by the lifting drive component to be inserted into the cleaning tank from top to bottom, so that the overflow port is flush with the cleaning fluid surface. As the overflow tank continues to move downward, the cleaning fluid overflows from the overflow port and is collected into the waste fluid collection tank. The cleaning fluid surface remains flush with the overflow port and gradually decreases, thus achieving precise control over the rate at which the cleaning fluid surface decreases. Therefore, compared with the prior art, this utility model, firstly, abandons the conventional method of using gravity as a driving force to control the water level drop. By adopting an overflow method and controlling the overflow height, it achieves precise control of the descent speed of the cleaning liquid surface, ensuring the stability of the cleaning liquid surface and effectively improving the drying effect on wafers based on the Marangoni principle. Secondly, based on multiple overflow notches to divert and form a buffer, it effectively improves the smoothness of the cleaning liquid overflow discharge, further reducing the fluctuations caused by the discharge and ensuring the stability of the Marangoni effect. Thirdly, the overflow position is close to the side wall of the overflow tank, so that the cleaning liquid surface can form an IPA liquid film that meets the area requirements. Fourthly, based on the connection and cooperation between the drain pipe, the overflow tank, and the lifting drive component, it is easy to match the extension and retraction movement of the drain pipe with the lifting and lowering movement of the overflow tank.

[0045] The present utility model has been described in detail above, with the aim of enabling those skilled in the art to understand its contents and implement it. However, this description should not be construed as limiting the scope of protection of the present utility model. All equivalent changes or modifications made in accordance with the spirit and essence of the present utility model should be included within the scope of protection of the present utility model.

Claims

1. A draining mechanism for a wafer cleaning tank, used to drain cleaning fluid from the cleaning tank, characterized in that, The drainage mechanism includes an overflow tank inserted into the cleaning tank, a lifting drive assembly that drives the overflow tank to move up and down, a waste liquid collection tank, and a drainage pipe connecting the overflow tank and the waste liquid collection tank. An overflow port is formed on the overflow tank. As the lifting drive assembly drives the overflow tank to move downward, the cleaning liquid overflows from the overflow port and is collected into the waste liquid collection tank. The cleaning liquid level is flush with the overflow port and gradually decreases.

2. The draining mechanism for a wafer cleaning tank according to claim 1, characterized in that, The overflow port includes multiple overflow notches spaced apart along the width of the cleaning tank, through which the cleaning fluid is diverted and enters the overflow tank.

3. The draining mechanism for a wafer cleaning tank according to claim 2, characterized in that, Each of the overflow gaps forms rounded corners at both ends along the overflow direction.

4. The draining mechanism for a wafer cleaning tank according to claim 1, characterized in that, The overflow tank includes a first side plate and a second side plate arranged from the inside to the outside along the thickness direction of the cleaning tank, an end plate connected between opposite sides of the first side plate and the second side plate, and a bottom plate connected between the bottom of the first side plate and the second side plate. The drain pipe is connected between the bottom plate and the waste liquid collection tank.

5. The draining mechanism for a wafer cleaning tank according to claim 4, characterized in that, The first side plate is bent from the top toward the second side plate to form a first bend, and the second side plate is bent from the top toward the first side plate to form a second bend located above the first bend, wherein the overflow port is formed between the first bend and the second bend.

6. The draining mechanism for a wafer cleaning tank according to claim 5, characterized in that, Multiple diversion sections are formed on the first bend, which are spaced apart along the width of the cleaning tank, wherein an overflow gap is formed between each two adjacent diversion sections.

7. The draining mechanism for a wafer cleaning tank according to claim 6, characterized in that, The plurality of diversion sections are vertically arranged on the first bend section near the end of the second side plate.

8. The draining mechanism for a wafer cleaning tank according to claim 4, characterized in that, The base plate extends vertically at an angle, and the connection point of the drain pipe on the base plate is located at the lowest end of the base plate.

9. The draining mechanism for a wafer cleaning tank according to claim 8, characterized in that, The drainage pipeline includes multiple pipes connected sequentially from top to bottom, wherein the diameter of the multiple pipes increases progressively from top to bottom.

10. The draining mechanism for a wafer cleaning tank according to claim 9, characterized in that, The top-level pipe is connected to the base plate via a connecting block, and the lifting drive assembly includes a telescopic rod connected to the connecting block and extending and retracting in the vertical direction.

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