Wafer cleaning apparatus

Abstract

The application discloses a wafer cleaning device, which comprises a cleaning machine body, a new liquid storage tank, a first liquid inlet valve, a liquid discharge valve and a liquid level sensor. The cleaning machine body is provided with a cleaning tank for accommodating wafers and cleaning liquid, and the cleaning tank is provided with a first liquid inlet and a liquid discharge port. The new liquid storage tank comprises a first storage tank for storing a first cleaning medium. The first storage tank is connected with the first liquid inlet through the first liquid inlet valve. The liquid discharge valve is used for controlling the opening and closing of the liquid discharge port. The liquid level sensor is used for detecting the liquid level in the cleaning tank. The wafer cleaning device comprises at least a first liquid supplementing mode and a waste liquid discharging mode. The wafer cleaning device disclosed by the application can realize the process of circulating waste liquid discharging and new liquid supplementing in the wafer cleaning process, maintain the effective component concentration of the cleaning liquid, improve the wafer initial cleaning yield, reduce the wafer re-cleaning quantity, and improve the equipment utilization rate and the production efficiency.

Description

Technical Field

[0001] This application relates to the field of semiconductor material processing technology, and more specifically, to a wafer cleaning device. Background Technology

[0002] Wafer cleaning is a process that uses chemical cleaning methods to remove dirt from an entire batch or a single wafer by immersing or spraying chemicals. Its main purpose is to remove contaminants such as dust particles, organic matter, inorganic matter, and metal ions from the wafer surface.

[0003] Existing silicon carbide wafer cleaning methods primarily employ acidic and alkaline solutions. During the process, as the number of silicon carbide wafers being cleaned increases, the effective components in the cleaning solution gradually decrease, and the solution's activity diminishes. Towards the end of the cleaning solution's lifespan, the cleaned silicon carbide wafers are prone to residual contaminants, necessitating re-cleaning. This re-cleaning significantly delays the overall processing progress, reduces cleaning yield, and can even cause irreversible damage to the silicon carbide wafer surface.

[0004] Therefore, how to improve the yield of the initial wafer cleaning and reduce the number of wafers to be re-cleaned has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] The purpose of this application is to disclose a wafer cleaning device to improve the yield of the first cleaning of wafers.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A wafer cleaning device includes a cleaning machine body, a new liquid storage tank, a first liquid inlet valve, a liquid outlet valve, and a liquid level sensor;

[0008] The cleaning machine body is provided with a cleaning tank for containing wafers and cleaning fluid. The cleaning tank is provided with a first inlet and a drain. The new fluid storage tank includes a first storage tank for storing the first cleaning medium.

[0009] The first storage tank is connected to the first liquid inlet via a first liquid inlet valve, and the liquid outlet valve is used to control the opening and closing of the liquid outlet;

[0010] The liquid level sensor is used to detect the liquid level in the cleaning tank;

[0011] The wafer cleaning equipment includes at least a first replenishment mode and a waste discharge mode. When the wafer cleaning equipment is in the first replenishment mode and the liquid level in the cleaning tank is lower than a first preset liquid level, the first inlet valve is in the open state and the drain valve is in the closed state. When the wafer cleaning equipment is in the waste discharge mode, the drain valve is in the open state and the first inlet valve is in the closed state.

[0012] One possible implementation also includes a timer. When the wafer cleaning equipment is in the first replenishment mode, the timer starts timing, and after a first preset time, the wafer cleaning equipment switches from the first replenishment mode to the waste discharge mode.

[0013] In one possible implementation, the first preset time is 40 to 80 minutes.

[0014] In one possible implementation, the timer is further configured to start timing when the wafer cleaning equipment is in the waste discharge mode, and after a second preset time, the wafer cleaning equipment turns off the waste discharge mode.

[0015] In one possible implementation, the second preset time is 10 to 30 seconds.

[0016] In one possible implementation, when the wafer cleaning equipment is in waste discharge mode, the waste discharge mode is turned off when the liquid level in the cleaning tank drops to a second preset liquid level, and the second preset liquid level is lower than the first preset liquid level.

[0017] In one possible implementation, a second inlet valve is also included, the new liquid storage tank further includes a second storage tank, the cleaning tank is further provided with a second inlet, and the second storage tank is connected to the second inlet via the second inlet valve;

[0018] The second storage tank is used to store the second cleaning medium, wherein the first cleaning medium is water and the second cleaning medium is a cleaning solution;

[0019] The wafer cleaning equipment also includes a second replenishment mode. When the wafer cleaning equipment is in the second replenishment mode, the first liquid inlet valve and the second liquid inlet valve are in the open state, and the drain valve is in the closed state.

[0020] In one possible implementation, when the wafer cleaning equipment is in the second replenishment mode, the second replenishment mode is turned off when the liquid level in the cleaning tank rises to the first preset liquid level.

[0021] One possible implementation also includes an alarm that sounds when the liquid level in the cleaning tank drops to the lower limit level or rises to the upper limit level, wherein the first preset liquid level is located between the lower limit level and the upper limit level.

[0022] In one possible implementation, the alarm includes an audible alarm and / or a visual alarm.

[0023] The wafer cleaning equipment disclosed in this application cycles through a first replenishment mode and a waste discharge mode during the wafer cleaning process, and the cycle flow is as follows:

[0024] First, the operator puts the wafer cleaning equipment into the first replenishment mode. Before the first replenishment mode starts, the liquid level in the cleaning tank is higher than the first preset level. As the number of wafers being cleaned increases, the cleaning fluid in the cleaning tank is consumed, and the liquid level gradually decreases. The liquid level sensor monitors the liquid level in the cleaning tank in real time. When the liquid level in the cleaning tank falls below the first preset level, the first inlet valve opens and the drain valve closes, allowing the first storage tank to inject the first cleaning medium into the cleaning tank, raising the liquid level in the cleaning tank until it exceeds the first preset level, at which point the first inlet valve closes. If the liquid level in the cleaning tank falls below the first preset level again, the above process is repeated to ensure that the liquid level in the cleaning tank is always maintained within the normal operating range of the wafer cleaning equipment.

[0025] When the impurities in the cleaning tank reach a certain amount or the set time has passed, the operator controls the first replenishment mode to end, the wafer cleaning equipment enters the waste discharge mode, the drain valve opens, the first inlet valve closes, and the waste liquid in the cleaning tank is discharged from the waste discharge port. This process removes the impurities accumulated in the cleaning tank during the first replenishment stage.

[0026] After the operator finishes controlling the waste discharge mode, the liquid level in the cleaning tank is replenished to above the first preset level. The wafer cleaning equipment then returns to the first replenishment mode to begin the cycle of the first replenishment mode and the waste discharge mode. The operator can set the number of cycles or manually terminate the cycle when necessary.

[0027] Compared to related technologies, the wafer cleaning equipment disclosed in this application maintains the effective component concentration of the cleaning solution by implementing a process of circulating waste liquid discharge and replenishing new liquid during the wafer cleaning process, ensuring the stability of the cleaning ability of the cleaning solution, thereby improving the initial wafer cleaning yield, reducing the number of wafers to be rewashed, reducing processing costs, and improving equipment utilization and production efficiency. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of the wafer cleaning equipment disclosed in the embodiments of this application.

[0030] The attached figures are labeled as follows:

[0031] 100. Cleaning tank; 110. First liquid inlet; 120. Second liquid inlet; 130. Drain outlet;

[0032] 200. First preset liquid level;

[0033] 300, Second preset liquid level;

[0034] 400. Drain valve. Detailed Implementation

[0035] The purpose of this application is to disclose a wafer cleaning device to improve the yield of the first cleaning of wafers.

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] See Figure 1 The wafer cleaning equipment disclosed in this application includes a cleaning machine body, a new liquid storage tank, a first liquid inlet valve, a liquid outlet valve 400, and a liquid level sensor.

[0038] The cleaning machine body includes a cleaning tank 100 for containing wafers and cleaning fluid. The cleaning tank 100 is primarily made of chemically resistant stainless steel and has a first inlet 110 and an outlet 130. A level sensor is installed inside the cleaning tank 100. The level sensor may include, but is not limited to, a float-type level sensor or a capacitive level sensor, which can be selected by those skilled in the art based on their needs. A first preset level 200 is set within the cleaning tank 100. This preset level 200 can be configured to achieve the desired cleaning effect for the wafers when the wafer cleaning equipment is operating. The specific structure of the cleaning machine body can be found in existing technology and will not be described in detail here.

[0039] The new liquid storage tank includes a first storage tank for storing the first cleaning medium. The first storage tank is connected to the first liquid inlet 110 of the cleaning tank 100 via a pipeline, on which a first liquid inlet valve is installed. The drain port 130 can be located at the bottom of the cleaning tank 100, and the opening and closing of the drain port 130 is controlled by a drain valve 400. The control method of the first liquid inlet valve and the drain valve 400 can be manual control or automatic control by a controller. In order to facilitate the subsequent centralized harmless treatment of waste liquid, the drain valve 400 can be connected to a waste liquid collection tank through a waste discharge pipeline. When the drain valve 400 is open, the waste liquid in the cleaning tank 100 is discharged from the drain port 130 and discharged into the waste liquid collection tank through the waste discharge pipeline.

[0040] The wafer cleaning equipment includes at least a first replenishment mode and a waste removal mode. Operators can control the start or end of the first replenishment mode and waste removal mode via buttons or a control panel based on process requirements. It should be noted that when the wafer cleaning equipment is in either the first replenishment mode or the waste removal mode, it is simultaneously performing wafer cleaning.

[0041] When the wafer cleaning equipment is in the first replenishment mode, if the liquid level in the cleaning tank 100 is lower than the first preset liquid level 200, the first inlet valve is open and the drain valve 400 is closed. If the liquid level in the cleaning tank 100 is higher than the first preset liquid level 200, the first inlet valve is closed and the drain valve 400 is closed. The first replenishment mode allows for timely replenishment of the first cleaning medium during continuous mass wafer cleaning, maintaining the liquid level in the cleaning tank at an ideal position and preventing excessive cleaning fluid loss leading to residual dirt on the wafers. This lays the foundation for continuous automated production.

[0042] It should be noted that the first cleaning medium can be pure water or a solution with the same composition as the cleaning liquid in the cleaning tank 100. In the first replenishment mode, the cleaning liquid in the cleaning tank 100 also has a strong cleaning effect. Therefore, water can be added to maintain the cleaning liquid in the cleaning tank 100 at the corresponding level, avoiding a significant drop in the liquid level that would affect the cleaning effect. Of course, a cleaning liquid with the same composition can also be added.

[0043] When the wafer cleaning equipment is in waste discharge mode, the drain valve 400 is open and the first inlet valve is closed. Waste discharge mode promptly removes used and contaminated waste liquid, preventing cross-contamination of the next batch of wafers. Furthermore, waste discharge mode only discharges a portion of the waste liquid, significantly reducing chemical consumption and waste liquid treatment costs compared to replacing the entire cleaning solution in the tank.

[0044] The wafer cleaning equipment disclosed in this application cycles through a first replenishment mode and a waste discharge mode during the wafer cleaning process, and the cycle flow is as follows:

[0045] First, the operator puts the wafer cleaning equipment into the first replenishment mode. Before the first replenishment mode starts, the liquid level in the cleaning tank 100 is higher than the first preset liquid level 200. As the number of wafers being cleaned increases, the cleaning fluid in the cleaning tank 100 is consumed, and the liquid level gradually decreases. The liquid level sensor monitors the liquid level in the cleaning tank in real time. When the liquid level in the cleaning tank is lower than the first preset liquid level 200, the first inlet valve opens and the drain valve 400 closes, allowing the first storage tank to inject the first cleaning medium into the cleaning tank 100, raising the liquid level in the cleaning tank until it is higher than the first preset liquid level 200, at which point the first inlet valve closes. If the liquid level in the cleaning tank falls below the first preset liquid level 200 again, the above process is repeated to ensure that the liquid level in the cleaning tank is always maintained within the normal operating range of the wafer cleaning equipment.

[0046] When the impurities in the cleaning tank 100 reach a certain amount or the set time has passed, the operator controls the first replenishment mode to end, the wafer cleaning equipment enters the waste discharge mode, the drain valve 400 is opened, the first inlet valve is closed, and the waste liquid in the cleaning tank is discharged from the drain port 130. This process removes the impurities accumulated in the cleaning tank 100 during the first replenishment stage.

[0047] After the operator finishes controlling the waste discharge mode, the liquid level in the cleaning tank is replenished to 200 mm above the first preset level. The wafer cleaning equipment then returns to the first replenishment mode to begin the cycle of the first replenishment mode and the waste discharge mode. The operator can set the number of cycles or manually terminate the cycle when necessary.

[0048] Compared to related technologies, the wafer cleaning equipment disclosed in this application maintains the effective component concentration of the cleaning solution by implementing a process of circulating waste liquid discharge and replenishing new liquid during the wafer cleaning process, ensuring the stability of the cleaning ability of the cleaning solution, thereby improving the initial wafer cleaning yield, reducing the number of wafers to be rewashed, reducing processing costs, and improving equipment utilization and production efficiency.

[0049] To precisely control the duration of the first replenishment mode, the wafer cleaning equipment also includes a timer. When the first replenishment mode is activated, the timer starts simultaneously, and after a first preset time, the equipment switches from replenishment mode to waste discharge mode. This design, based on experience and data from specific processes, sets a conservative and safe time interval, precisely controlling the duration of the first replenishment mode. It eliminates the need to train operators to understand the relationship between chemical concentration and process effectiveness, and to monitor concentration data, reducing the possibility of human error. This not only saves labor costs but also significantly improves response speed and execution efficiency.

[0050] In one specific implementation, the first preset time can be 40 to 80 minutes. The first preset time can be set based on the cleaning quality of the silicon carbide wafers. For example, if the wafer cleaning equipment operates in the first replenishment mode for 60 minutes, and during this time the cleaned wafer surface has no residual cleaning solution or other polishing fluid, meeting the cleaning quality requirements, then the first preset time can be set to 60 minutes. Because the first replenishment mode, through continuous replenishment of the first cleaning medium and stable liquid level control, maintains a stable and predictable chemical environment (concentration, particle size) within the cleaning tank 100, frequent waste discharge and replenishment will cause fluctuations in the cleaning solution concentration. Setting the first preset time longer, extending the duration of the first replenishment mode until the activity of the cleaning solution is about to reach its critical point, helps reduce the process risks such as uneven cleaning and insufficient cleaning caused by frequent waste discharge and replenishment. This ensures that wafers in the same batch are cleaned within the first replenishment mode, resulting in almost identical cleaning rates and particle removal efficiencies, greatly guaranteeing high product yield and electrical performance consistency, maximizing the effective lifespan of the cleaning solution, thereby improving overall economic efficiency and process stability.

[0051] The timer can also be used to time the waste discharge mode. When the wafer cleaning equipment activates the waste discharge mode, the timer starts counting, and after a second preset time, the wafer cleaning equipment deactivates the waste discharge mode. Technicians can set the second preset time based on process requirements. This design precisely controls the waste discharge time, thereby controlling the waste liquid volume and ensuring consistency in waste liquid volume between cycles. This helps maintain the concentration stability of the chemical solution within the cleaning tank 100, avoiding batch-to-batch differences, ensuring process stability, and improving the automation level of the wafer cleaning equipment.

[0052] In one specific implementation, the second preset time can be set to 10 to 30 seconds. For example, if a technician, through one or more actual tests, calibrates that the actual discharged liquid volume meets the process requirements within 20 seconds, then the second preset time is set to 20 seconds. The second preset time is shorter than the first preset time, which helps to reduce the drastic disturbances in the cleaning solution concentration caused by the waste discharge mode to the entire wafer cleaning process.

[0053] In another specific implementation, the waste discharge mode can be controlled by liquid level. When the wafer cleaning equipment is in waste discharge mode, the drain valve 400 opens, the liquid level in the cleaning tank drops, and when it drops to the second preset liquid level 300, the drain valve 400 closes, and the waste discharge mode ends. The second preset liquid level 300 is a pre-calibrated liquid level that serves as a signal for stopping waste discharge. The second preset liquid level 300 is lower than the first preset liquid level 200. This design ensures that regardless of any changes in the flow rate during waste discharge, the waste discharge operation continues until the liquid volume in the cleaning tank 100 is precisely reduced to the second preset liquid level 300, exhibiting high precision and stability.

[0054] In one specific implementation, the new liquid storage tank further includes a second storage tank for storing a second cleaning medium. The first cleaning medium can be water, and the second cleaning medium can be a cleaning solution.

[0055] The cleaning tank 100 is also provided with a second liquid inlet 120. The second storage tank is connected to the second liquid inlet 120 of the cleaning tank 100 through a pipeline, and a second liquid inlet valve is provided on the connecting pipeline.

[0056] The wafer cleaning equipment also includes a second replenishment mode, which operators can control to start or stop via buttons or a control panel based on process requirements. It should be noted that when the wafer cleaning equipment is in the second replenishment mode, it is simultaneously performing wafer cleaning. In this mode, the first and second inlet valves are open, while the drain valve 400 is closed.

[0057] During the wafer cleaning process, after the operator completes the waste discharge mode, the second replenishment mode is activated. The first and second inlet valves open, while the drain valve 400 closes. The first and second storage tanks inject water and cleaning solution into the cleaning tank 100, quickly restoring the total volume and concentration of the liquid in the tank to the required levels. The wafer cleaning equipment then returns to the first replenishment mode for the next cycle of replenishment and waste discharge. This design features a first replenishment mode that only adds water, while the second replenishment mode replenishes the effective chemical components consumed in the previous cycle. This not only maintains the activity of the cleaning chemicals but also significantly reduces the amount of expensive cleaning solutions used, directly lowering production and operating costs.

[0058] To further automate the wafer cleaning equipment, a second replenishment mode can be implemented using level control. In this mode, the first and second inlet valves open, raising the liquid level in the cleaning tank 100 until it reaches the first preset level of 200. At this point, the first and second inlet valves close, ending the second replenishment mode. This design precisely controls the replenishment volume of water and cleaning solutions, ensuring a stable chemical concentration within the cleaning tank 100 and maintaining it within the effective process window. This guarantees continuous, high-quality cleaning results and allows the equipment to automatically enter the next cycle after completing one cycle, significantly improving equipment utilization and production efficiency. It is suitable for large-scale production lines requiring long-duration, multi-batch cleaning.

[0059] To improve the safety of wafer cleaning equipment operation, an alarm is also included. The alarm sounds when the liquid level in the cleaning tank 100 drops to the lower limit or rises to the upper limit. A first preset liquid level 200 is located between the lower and upper limits, and a second preset liquid level 300 is located between the first preset level 200 and the lower limit. This design enables timely prevention and handling of malfunctions, improving the overall reliability and service life of the wafer cleaning equipment.

[0060] In one specific implementation, the alarm may include a sound alarm and / or a light alarm, which greatly reduces the possibility of missing critical alarm information due to environmental interference or human negligence, and ensures that information is perceived, understood and responded to in a timely manner in complex and diverse industrial environments.

[0061] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units may include steps or units not listed, but rather steps or units not listed. Additionally, in the description of embodiments in this application, "a plurality of" means two or more.

[0062] In the description of this application, it should be understood that the terms "height," "thickness," "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used 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. In the description of this application, "a plurality of" means two or more, and "at least one" can mean one, two, or more, unless otherwise expressly specified.

[0063] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Specific technical means in some embodiments may be incorporated, in whole or in part, into another embodiment unless explicitly excluded by another embodiment. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wafer cleaning device, characterized in that, Includes the cleaning machine body, a new liquid storage tank, a first liquid inlet valve, a liquid outlet valve (400), and a liquid level sensor; The cleaning machine body is provided with a cleaning tank (100) for containing wafers and cleaning fluid. The cleaning tank (100) is provided with a first inlet (110) and a drain (130). The new liquid storage tank includes a first storage tank for storing a first cleaning medium. The first storage tank is connected to the first inlet (110) via a first inlet valve, and the drain valve (400) is used to control the opening and closing of the drain (130); The liquid level sensor is used to detect the liquid level in the cleaning tank (100); The wafer cleaning equipment includes at least a first replenishment mode and a waste discharge mode. When the wafer cleaning equipment is in the first replenishment mode and the liquid level in the cleaning tank (100) is lower than the first preset liquid level (200), the first inlet valve is in the open state and the drain valve (400) is in the closed state. When the wafer cleaning equipment is in the waste discharge mode, the drain valve (400) is in the open state and the first inlet valve is in the closed state.

2. The wafer cleaning equipment as described in claim 1, characterized in that, It also includes a timer. When the wafer cleaning equipment is in the first replenishment mode, the timer starts timing, and after a first preset time, the wafer cleaning equipment switches from the first replenishment mode to the waste discharge mode.

3. The wafer cleaning equipment as described in claim 2, characterized in that, The first preset time is 40 minutes to 80 minutes.

4. The wafer cleaning equipment as described in claim 2, characterized in that, The timer is also used to start timing when the wafer cleaning equipment is in the waste discharge mode, and after a second preset time, the wafer cleaning equipment turns off the waste discharge mode.

5. The wafer cleaning equipment as described in claim 4, characterized in that, The second preset time is 10 seconds to 30 seconds.

6. The wafer cleaning equipment as described in claim 2, characterized in that, When the wafer cleaning equipment is in waste discharge mode, when the liquid level in the cleaning tank (100) drops to the second preset liquid level (300), the waste discharge mode is turned off, and the second preset liquid level (300) is lower than the first preset liquid level (200).

7. The wafer cleaning equipment according to any one of claims 1-6, characterized in that, It also includes a second liquid inlet valve, the new liquid storage tank also includes a second storage tank, the cleaning tank (100) is also provided with a second liquid inlet (120), and the second storage tank is connected to the second liquid inlet (120) through the second liquid inlet valve; The second storage tank is used to store the second cleaning medium, wherein the first cleaning medium is water and the second cleaning medium is a cleaning solution; The wafer cleaning equipment also includes a second replenishment mode. When the wafer cleaning equipment is in the second replenishment mode, the first liquid inlet valve and the second liquid inlet valve are in the open state, and the drain valve (400) is in the closed state.

8. The wafer cleaning equipment as described in claim 7, characterized in that, When the wafer cleaning equipment is in the second replenishment mode, the second replenishment mode is turned off when the liquid level in the cleaning tank (100) rises to the first preset liquid level (200).

9. The wafer cleaning equipment according to any one of claims 1-6, characterized in that, It also includes an alarm that sounds when the liquid level in the cleaning tank (100) drops to the lower limit level or rises to the upper limit level, wherein the first preset liquid level (200) is located between the lower limit level and the upper limit level.

10. The wafer cleaning equipment as described in claim 9, characterized in that, The alarm includes a sound alarm and / or a light alarm.

Images