Wafer immersion cleaning device and liquid replenishing method

Abstract

The present application relates to the field of semiconductor device manufacturing technology, and specifically to a wafer immersion cleaning device and a liquid replenishing method. The device includes: an immersion inner tank, a liquid replenishing outer tank, and a liquid replenishing device. The method includes: controlling the input of cleaning liquid into the liquid replenishing outer tank so that the liquid level of the cleaning liquid in the liquid replenishing outer tank gradually rises; when a first trigger signal sent by a first liquid level sensor is obtained, the liquid replenishing device is started when a second trigger signal sent by a second liquid level sensor is obtained for the first time; when the second trigger signal sent by the second liquid level sensor is obtained for the second time, it is determined that the liquid replenishment of the immersion inner tank is complete, and the cleaning liquid overflows after the immersion inner tank is filled, so that the liquid level of the cleaning liquid in the liquid replenishing outer tank rises to a second height; when a third trigger signal sent by a third liquid level sensor is obtained, the liquid replenishing device is stopped and the drain valve is opened; when a jump signal sent by the second liquid level sensor is obtained, the drain valve is closed and the liquid replenishing device is started.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor device manufacturing, and in particular to a wafer immersion cleaning device and a liquid replenishing method. Background Art

[0002] During the semiconductor integrated circuit manufacturing process, most process steps require cleaning. For example, after completing the manufacturing process involving corrosion and ion impact, the wafer needs to be cleaned to remove the corrosive liquid remaining on the wafer surface and the byproducts formed by the ion impact, which is beneficial to the production of subsequent device layers.

[0003] Related technologies usually use a spray process to clean the surface of the chip, but the spray cleaning process is prone to insufficient cleaning and has problems with cleaning dead corners, which makes it difficult to meet process requirements. As a result, an immersion cleaning process has emerged. However, the immersion cleaning process in the related technology also has some rehydration problems such as insufficient rehydration, which can lead to insufficient chip cleaning and fault alarms. Summary of the Invention

[0004] The present application provides a wafer immersion cleaning device and a liquid replenishing method, which can solve the liquid replenishing problem of the immersion cleaning process in the related art.

[0005] In order to solve the technical problems described in the background technology, the first aspect of the present application provides a wafer immersion cleaning device, the wafer immersion cleaning device comprising an inner immersion tank for immersing and cleaning wafers, an outer refilling tank for replenishing liquid into the inner immersion tank, and a refilling device for transporting cleaning liquid in the outer refilling tank to the inner immersion tank;

[0006] The outer rehydration tank is at least tightly fitted to the upper periphery of the inner immersion tank, and the upper end of the inner immersion tank is connected to the outer rehydration tank, so that the cleaning liquid overflowing from the upper end of the inner immersion tank can flow into the outer rehydration tank;

[0007] Along the height direction of the liquid replenishing outer tank, a first liquid level sensor, a second liquid level sensor and a third liquid level sensor are sequentially provided from bottom to top;

[0008] The outer refill tank is also provided with a drain valve for discharging the cleaning liquid;

[0009] When the liquid level of the cleaning liquid in the liquid replenishing outer tank rises to a first height, the first liquid level sensor sends a first trigger signal;

[0010] When the liquid level of the cleaning liquid in the liquid replenishing outer tank rises to a second height, the first liquid level sensor sends a first trigger signal, and the second liquid level sensor sends a second trigger signal;

[0011] When the liquid level of the cleaning liquid in the liquid replenishing outer tank rises to a third height, the first liquid level sensor sends a first trigger signal, the second liquid level sensor sends a second trigger signal, and the third liquid level sensor sends a third trigger signal.

[0012] In order to solve the technical problems described in the background technology, the second aspect of the present application provides a method for replenishing liquid in a wafer immersion cleaning device. The method for replenishing liquid in a wafer immersion cleaning device comprises performing the following steps using the wafer immersion cleaning device described in the first aspect of the present application:

[0013] Step 1: Controlling the input of cleaning fluid into the fluid replenishment outer tank so that the liquid level of the cleaning fluid in the fluid replenishment outer tank gradually rises;

[0014] Step 2: After obtaining the first trigger signal sent by the first liquid level sensor, when obtaining the second trigger signal sent by the second liquid level sensor for the first time, determining that the liquid level of the cleaning liquid in the liquid replenishing outer tank rises to a second height;

[0015] Step 3: activating the fluid replenishing device to transfer the cleaning fluid in the fluid replenishing outer tank to the immersion inner tank, so that the liquid level of the cleaning fluid in the fluid replenishing outer tank begins to drop from the second height;

[0016] Step 4: When the second trigger signal sent by the second liquid level sensor is obtained for the second time, it is determined that the inner immersion tank is completely replenished with liquid, and the cleaning liquid overflows after the inner immersion tank is filled, so that the liquid level of the cleaning liquid in the liquid replenishment outer tank rises to a second height;

[0017] Step 5: When the third trigger signal sent by the third liquid level sensor is obtained, it is determined that the liquid level of the cleaning liquid in the liquid replenishing outer tank rises to a third height, so that the liquid replenishing device stops and the drain valve opens.

[0018] Step 6: Obtaining the jump signal sent by the second liquid level sensor, determining to open the drain valve so that the liquid level of the cleaning liquid in the liquid replenishment outer tank drops to a second height, closing the drain valve, and activating the liquid replenishment device; wherein the jump signal is a step instantaneous signal at which the second liquid level sensor stops sending the second trigger signal;

[0019] Repeat steps 5 and 6 in sequence.

[0020] Optionally, the method further comprises the steps of:

[0021] When the second trigger signal sent by the second liquid level sensor is obtained, determining whether the second liquid level sensor sends the second trigger signal due to a liquid level peak-valley error;

[0022] When it is determined that the second liquid level sensor sends the second trigger signal due to a liquid level peak-valley error, the second trigger signal is invalidated.

[0023] Optionally, when obtaining the second trigger signal sent by the second liquid level sensor, the step of determining whether the second liquid level sensor sends the second trigger signal due to a liquid level peak-valley error includes:

[0024] When the second trigger signal sent by the second liquid level sensor is obtained, calculating the duration of continuous sending of the second trigger signal by the second liquid level sensor within a preset time;

[0025] Determining whether the continuous sending duration exceeds a time threshold;

[0026] When the continuous sending time exceeds the time threshold, it is determined that the second trigger signal sent by the second liquid level sensor is not caused by a liquid level peak and trough error.

[0027] Optionally, after the fourth step of determining that the inner immersion tank is completely replenished and the cleaning liquid overflows after the inner immersion tank is filled, so that the liquid level of the cleaning liquid in the liquid replenishment outer tank rises to the second height when the second trigger signal sent by the second liquid level sensor is obtained for the second time is completed, before performing the fifth step of determining that the liquid level of the cleaning liquid in the liquid replenishment outer tank rises to the third height when the third trigger signal sent by the third liquid level sensor is obtained, so that the liquid replenishment device stops and the drain valve opens, the following steps are further performed:

[0028] The cleaning fluid is input into the fluid replenishment outer tank at a first flow rate, and the cleaning fluid in the fluid replenishment outer tank is discharged at a fourth flow rate to slow down the speed at which the cleaning fluid in the fluid replenishment outer tank continues to rise from the second height.

[0029] Optionally, the fourth flow rate is smaller than the first flow rate.

[0030] Optionally, the wafer immersion cleaning device refilling method further includes the following steps:

[0031] determining whether the liquid level of the cleaning fluid in the liquid replenishing outer tank is lower than the first height based on whether the first trigger signal sent by the first liquid level sensor is received;

[0032] When it is determined that the first trigger signal sent by the first liquid level sensor is received, it is determined that the liquid level of the cleaning fluid in the liquid replenishing outer tank has reached the first height; otherwise, it is determined that the liquid level of the cleaning fluid in the liquid replenishing outer tank has not reached the first height, and an alarm is triggered.

[0033] Optionally, the wafer immersion cleaning device refilling method further includes the following steps:

[0034] When determining to obtain the third trigger signal, determining whether the first liquid level sensor and / or the second liquid level sensor is invalid based on whether the first trigger signal and / or the second trigger signal is obtained;

[0035] When the third trigger signal is obtained, the first trigger signal and / or the second trigger signal is not obtained, it is determined that the first liquid level sensor and / or the second liquid level sensor is invalid, and an alarm is triggered.

[0036] The technical solution of the present application has at least the following advantages: the cleanliness of the cleaning liquid in the immersion tank is guaranteed under the premise of sufficient liquid replenishment in the immersion tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0038] Figure 1 A schematic structural diagram of a wafer immersion cleaning device provided in one embodiment of the present application is shown;

[0039] Figure 2 A flow chart of a method for replenishing liquid in a wafer immersion cleaning device according to an embodiment of the present application is shown;

[0040] Figure 3 A schematic diagram showing the process of determining whether the second liquid level sensor sends the second trigger signal due to a liquid level peak-valley error in step S31 is shown;

[0041] Figure 4 It shows that other embodiments of the present application also provide a flow chart of a method for replenishing liquid in a wafer immersion cleaning device. DETAILED DESCRIPTION

[0042] The following is a clear and complete description of the technical solutions in this application in conjunction with the accompanying drawings. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0043] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this application and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal connections between two components; they can refer to wireless connections or wired connections. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0045] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0046] Figure 1 The schematic diagram of the structure of a wafer immersion cleaning device provided by an embodiment of the present application is shown. Figure 1 As can be seen in the figure, the wafer immersion cleaning device includes: an immersion inner tank 110 for immersing and cleaning wafers, a liquid replenishing outer tank 120 for replenishing liquid to the immersion inner tank, and a liquid replenishing device for transporting the cleaning liquid in the liquid replenishing outer tank to the immersion inner tank. Figure 1 The fluid replenishment device is not shown in FIG.

[0047] The liquid replenishing outer tank 120 is at least tightly fitted to the upper periphery of the immersion inner tank 110 , and the upper end 111 of the immersion inner tank 110 is connected to the liquid storage cavity 121 of the liquid replenishing outer tank 120 , so that the cleaning liquid overflowing from the upper end 111 of the immersion inner tank 110 can flow into the liquid storage cavity 121 of the liquid replenishing outer tank 120 .

[0048] from Figure 1 It can also be seen that along the height direction of the liquid replenishing outer tank 120, a first liquid level sensor L, a second liquid level sensor H and a third liquid level sensor HH are sequentially provided from bottom to top.

[0049] The outer refill tank 120 is also provided with a drain valve for discharging the cleaning liquid. Figure 1 The drain valve is not shown.

[0050] Among them, when the liquid level of the cleaning liquid rises to a first height, the first liquid level sensor L sends a first trigger signal; when the liquid level of the cleaning liquid rises to a second height, the first liquid level sensor L sends a first trigger signal, and the second liquid level sensor H sends a second trigger signal; when the liquid level of the cleaning liquid rises to a third height, the first liquid level sensor L sends a first trigger signal, the second liquid level sensor H sends a second trigger signal, and the third liquid level sensor HH sends a third trigger signal.

[0051] However, in the prior art, a lower limit protection sensor is usually provided under the first liquid level sensor L, and the liquid replenishment operation scheme is performed between the first liquid level sensor L and the second liquid level sensor H. However, the liquid replenishment operation scheme in the prior art is difficult to adapt to the present application. Figure 1 The wafer immersion cleaning device shown is prone to the problem of liquid replenishment logic errors. In order to solve this problem, the present application also provides the following liquid replenishment method for the wafer immersion cleaning device.

[0052] Figure 2 The flow chart of the method for replenishing liquid in a wafer immersion cleaning device provided by an embodiment of the present application is shown. Figure 2 As can be seen from the figure, the method for replenishing the wafer immersion cleaning device includes the following steps:

[0053] Step S21: controlling the input of cleaning fluid into the liquid-replenishing outer tank so that the liquid level of the cleaning fluid in the liquid-replenishing outer tank gradually rises.

[0054] In this embodiment, the cleaning fluid may be controlled to be input into the fluid replenishment outer tank at a first flow rate.

[0055] Optionally, when performing step S21 in this embodiment, the inner immersion tank 110 is not filled with cleaning liquid.

[0056] The level of the cleaning liquid rising in the liquid storage chamber 121 of the liquid replenishing outer tank 120 gradually rises to a first height. When the level of the cleaning liquid rises to the first height, the first liquid level sensor L is triggered, causing the first liquid level sensor L to send a first trigger signal. The liquid level in the liquid storage chamber 121 of the liquid replenishing outer tank 120 continues to rise.

[0057] When the liquid level of the cleaning fluid in the liquid replenishing outer tank 120 rises to a second height, the second liquid level sensor H is triggered on the basis of triggering the first liquid level sensor L, so that the first liquid level sensor L sends a first trigger signal and the second liquid level sensor H sends a second trigger signal.

[0058] Step S22: After obtaining the first trigger signal sent by the first liquid level sensor, when obtaining the second trigger signal sent by the second liquid level sensor for the first time, determining that the liquid level of the cleaning liquid in the liquid replenishing outer tank rises to a second height.

[0059] Step S23: starting the fluid replenishing device, and delivering the cleaning fluid in the fluid replenishing outer tank to the immersion inner tank, so that the liquid level of the cleaning fluid in the fluid replenishing outer tank begins to drop from the second height.

[0060] In this embodiment, when the level of the cleaning fluid in the external rehydration tank 120 rises to a second height, the cleaning fluid in the external rehydration tank 120 is delivered to the inner immersion tank 110 at a second flow rate. The second flow rate is greater than the first flow rate. As a result, when the rehydration device is activated, the level of the cleaning fluid in the external rehydration tank 120 begins to drop from the second height, while the level of the cleaning fluid in the inner immersion tank 110 gradually rises.

[0061] Step S24: When the second trigger signal sent by the second liquid level sensor is obtained for the second time, it is determined that the inner immersion tank is completely replenished, and the cleaning liquid overflows after the inner immersion tank is filled, so that the liquid level of the cleaning liquid in the outer replenishment tank rises to a second height.

[0062] Since the upper end 111 of the immersion inner tank 110 is connected to the liquid storage chamber 121 of the liquid replenishing outer tank 120, the cleaning liquid overflowing from the upper end 111 of the immersion inner tank 110 can flow into the liquid storage chamber 121 of the liquid replenishing outer tank 120. As a result, as the liquid replenishing device operates, the height of the cleaning liquid in the immersion inner tank 110 gradually increases until the immersion inner tank 110 is filled with cleaning liquid. The cleaning liquid that continues to be input into the immersion inner tank 110 will overflow into the liquid storage chamber 121 of the liquid replenishing outer tank 120 at a second flow rate.

[0063] The flow rate of the cleaning liquid overflowing into the liquid replenishing outer tank 120 is consistent with the flow rate of the cleaning liquid output from the liquid replenishing outer tank 120 to the immersion inner tank 110, thereby continuously controlling the cleaning liquid input into the liquid replenishing outer tank 120 at a first flow rate, so that the liquid level of the cleaning liquid in the liquid replenishing outer tank 120 continues to rise, and reaches the second height again and triggers the second liquid level sensor as a basis to determine that the immersion inner tank 110 is fully replenished and the immersion inner tank 110 is filled with cleaning liquid.

[0064] Step S25: When the third trigger signal sent by the third liquid level sensor is obtained, it is determined that the liquid level of the cleaning liquid in the liquid replenishing outer tank rises to a third height, so that the liquid replenishing device stops and the drain valve opens.

[0065] When step S24 is completed and the liquid level of the cleaning liquid in the liquid infusion outer tank 120 triggers the second liquid level sensor again, the cleaning liquid input into the liquid infusion outer tank 120 at the first flow rate is still continuously controlled, so that the liquid level of the cleaning liquid in the liquid infusion outer tank 120 continues to rise until it rises to the third height, triggering the third liquid level sensor, indicating that there is too much cleaning liquid in the liquid infusion outer tank 120 and it needs to be drained in time. Therefore, when obtaining the third trigger signal sent by the third liquid level sensor, it is necessary to stop the liquid infusion device and open the drain valve to discharge the cleaning liquid in the liquid infusion outer tank 120 at the third flow rate, where the third flow rate is greater than the first flow rate.

[0066] Therefore, after the cleaning liquid in the liquid-replenishing outer tank 120 is discharged at the third flow rate, the liquid level of the cleaning liquid in the liquid-replenishing outer tank 120 gradually decreases.

[0067] Step S26: When the jump signal sent by the second liquid level sensor is obtained, it is determined to open the drain valve so that the liquid level of the cleaning liquid in the liquid replenishment outer tank drops to a second height, so that the drain valve is closed, and the liquid replenishment device is started, wherein the jump signal is a step instantaneous signal at which the second liquid level sensor stops sending the second trigger signal.

[0068] In step S25, after the cleaning liquid in the liquid replenishing outer tank 120 is discharged at the third flow rate, the liquid level of the cleaning liquid in the liquid replenishing outer tank 120 gradually decreases from the third height until the liquid level of the cleaning liquid in the liquid replenishing outer tank 120 just drops to the second height. The second liquid level sensor is at the critical turntable from triggered to untriggered, and the second liquid level sensor sends a jump signal.

[0069] After step S26 is completed, step S25 to step S26 are looped to circulate the cleaning liquid in the immersion inner tank 110 and maintain the cleanliness of the cleaning liquid in the immersion inner tank 110.

[0070] It should be explained that, in each step from step S21 to step S26 , the cleaning fluid is input into the fluid replenishment outer tank at the first flow rate in a consistent and continuous manner.

[0071] This embodiment can ensure the cleanliness of the cleaning liquid in the immersion inner tank under the premise of sufficient liquid replenishment.

[0072] In this embodiment, in order to determine whether the second trigger signal sent by the second liquid level sensor is caused by fluctuations in the liquid level before the liquid level reaches the second height, the following steps are further performed when the second trigger signal sent by the second liquid level sensor is obtained:

[0073] Step S31: When the second trigger signal sent by the second liquid level sensor is obtained, it is determined whether the second liquid level sensor sends the second trigger signal due to a liquid level peak-valley error.

[0074] Step S32: when it is determined that the second liquid level sensor sends the second trigger signal due to the liquid level peak and trough error, the second trigger signal is invalidated.

[0075] When the second trigger signal is invalidated, it is deemed that the second trigger signal has not been received.

[0076] In addition, refer to Figure 3 , which shows a schematic diagram of the process of determining whether the second liquid level sensor sends the second trigger signal due to the liquid level peak and trough error in step S31, Figure 3 As can be seen from the figure, step S31 includes the following steps S311 to S313, wherein:

[0077] Step S311: when the second trigger signal sent by the second liquid level sensor is obtained, the duration of the second trigger signal sent by the second liquid level sensor within a preset time is calculated.

[0078] Step S312: Determine whether the duration of the continuous sending exceeds a time threshold.

[0079] Step S313: When the duration of the continuous transmission exceeds a time threshold, it is determined that the second trigger signal sent by the second liquid level sensor is not caused by a liquid level peak or trough error.

[0080] If the second liquid level sensor H sends the second trigger signal when the liquid level has not reached the second height due to the error of liquid level peaks and troughs, the continuous sending time of the second trigger signal is shorter. If the second liquid level sensor H sends the second trigger signal due to the liquid level rising to the second height, the continuous sending time of the second trigger signal is longer. Therefore, it is judged based on the length of the continuous sending time of the second trigger signal whether the second trigger signal sent by the second liquid level sensor H is caused by the error of liquid level peaks and troughs.

[0081] The time threshold can be preset according to requirements.

[0082] When it is determined that the second trigger signal sent by the second liquid level sensor is caused by a liquid level peak-valley error, an alarm is triggered.

[0083] In order to further maintain the cleanliness of the cleaning liquid in the immersion tank 110, other embodiments of the present application also provide a method for replenishing the liquid in the wafer immersion cleaning device, referring to Figure 4 ,based on Figure 1On the basis of the illustrated embodiment, this embodiment, after completing step S24: when obtaining the second trigger signal sent by the second liquid level sensor for the second time, determining that the inner immersion tank is completely replenished, and the cleaning liquid overflows after the inner immersion tank is filled, so that the liquid level of the cleaning liquid in the liquid replenishment outer tank rises to the second height, and then performing step S25: when obtaining the third trigger signal sent by the third liquid level sensor, determining that the liquid level of the cleaning liquid in the liquid replenishment outer tank rises to the third height, so that the liquid replenishment device stops, and before the drain valve is opened, further performs the following steps:

[0084] Step S41: controlling the input of cleaning fluid into the fluid-replenishing outer tank at a first flow rate, and controlling the discharge of cleaning fluid from the fluid-replenishing outer tank at a fourth flow rate, so as to slow down the speed at which the cleaning fluid in the fluid-replenishing outer tank continues to rise from the second height.

[0085] Among them, the fourth flow rate for discharging the liquid replenishing outer tank 120 is less than the first flow rate for delivering into the liquid replenishing outer tank, so that the liquid level of the cleaning liquid in the liquid replenishing outer tank still rises, but the rising speed is lower than when the discharge operation is not performed, thereby extending the time for updating the cleaning liquid in the immersion inner tank 110 by delivering overflow to maintain the cleanliness of the cleaning liquid, which is beneficial to further maintain the cleanliness of the cleaning liquid in the immersion inner tank 110.

[0086] Since the liquid is replenished from the liquid replenishing outer tank 120 to the immersion inner tank 110 so that the immersion inner tank 110 is filled with cleaning liquid and the cleanliness of the cleaning liquid is maintained, it is necessary to prevent the liquid level in the liquid replenishing outer tank 120 from being too low. In order to prevent the liquid level in the liquid replenishing outer tank 120 from being too low, the embodiment of the present application further includes the following steps:

[0087] Step S51: determining whether the liquid level of the cleaning fluid in the liquid replenishing outer tank is lower than the first height based on whether the first trigger signal sent by the first liquid level sensor is received.

[0088] Step S52: When it is determined that the first trigger signal sent by the first liquid level sensor is received, it is determined that the liquid level of the cleaning fluid in the liquid replenishing outer tank has reached the first height; otherwise, it is determined that the liquid level of the cleaning fluid in the liquid replenishing outer tank has not reached the first height, and an alarm is triggered.

[0089] Among them, in order to avoid errors caused by liquid level fluctuations, that is, the actual liquid level height has not reached the first height, but the first liquid level sensor L is triggered due to the liquid level fluctuations, after judging that the first trigger signal sent by the first liquid level sensor L is received, the duration of the first trigger signal sent by the first liquid level sensor L can be calculated, and whether the first trigger signal is caused by the liquid level fluctuations is determined according to the length of the duration.

[0090] When the first trigger signal sent by the first liquid level sensor L is received for a long time, it is determined that the first trigger signal is not caused by liquid level fluctuation, but the liquid level of the cleaning liquid in the liquid replenishment outer tank 120 rises to the first height.

[0091] In order to avoid problems in the fluid replenishment process of this embodiment due to sensor failure, this embodiment further performs the following steps:

[0092] Step S61: When determining whether the third trigger signal is obtained, determine whether the first liquid level sensor and / or the second liquid level sensor is invalid based on whether the first trigger signal and / or the second trigger signal is obtained.

[0093] Step S62: When the third trigger signal is obtained, the first trigger signal and / or the second trigger signal are not obtained, and it is determined that the first liquid level sensor and / or the second liquid level sensor is invalid, and an alarm is triggered.

[0094] When the third trigger signal is obtained, if the first liquid level sensor L and / or the second liquid level sensor H are normal, the first trigger signal and the second trigger signal will definitely be received. Therefore, once the first trigger signal and / or the second trigger signal are not obtained, it is determined that the first liquid level sensor L and / or the second liquid level sensor H has failed.

[0095] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of this application.

Claims

1. A method for replenishing liquid in a wafer immersion cleaning device, characterized in that: include: A wafer immersion cleaning device is provided, comprising an inner immersion tank, an outer liquid replenishing tank and a liquid replenishing device; The outer rehydration tank is tightly fitted on the upper periphery of the inner immersion tank, and the upper end of the inner immersion tank is connected to the outer rehydration tank, so that the cleaning liquid overflowing from the upper end of the inner immersion tank can flow into the outer rehydration tank; Along the height direction of the liquid replenishing outer tank, a first liquid level sensor, a second liquid level sensor and a third liquid level sensor are sequentially provided from bottom to top; The outer refill tank is also provided with a drain valve for discharging the cleaning liquid; Step 1: Controlling the input of cleaning fluid into the fluid replenishment outer tank so that the liquid level of the cleaning fluid in the fluid replenishment outer tank gradually rises; Step 2: After obtaining the first trigger signal sent by the first liquid level sensor, when obtaining the second trigger signal sent by the second liquid level sensor for the first time, determining that the liquid level of the cleaning liquid in the liquid replenishing outer tank rises to a second height; Step 3: activating the fluid replenishing device to transfer the cleaning fluid in the fluid replenishing outer tank to the immersion inner tank, so that the liquid level of the cleaning fluid in the fluid replenishing outer tank begins to drop from the second height; Step 4: When the second trigger signal sent by the second liquid level sensor is obtained for the second time, it is determined that the inner immersion tank is completely replenished with liquid, and the cleaning liquid overflows after the inner immersion tank is filled, so that the liquid level of the cleaning liquid in the liquid replenishment outer tank rises to a second height; Step 5: When a third trigger signal is received from the third liquid level sensor, it is determined that the liquid level of the cleaning liquid in the liquid replenishing outer tank has risen to a third height, the liquid replenishing device is stopped, and the drain valve is opened; Step 6: Obtaining the jump signal sent by the second liquid level sensor, determining to open the drain valve so that the liquid level of the cleaning liquid in the liquid replenishment outer tank drops to a second height, closing the drain valve, and activating the liquid replenishment device; wherein the jump signal is a step instantaneous signal at which the second liquid level sensor stops sending the second trigger signal; Repeat steps 5 and 6 in sequence.

2. The method for replenishing liquid in a wafer immersion cleaning device according to claim 1, wherein: Also includes the steps: When the second trigger signal sent by the second liquid level sensor is obtained, determining whether the second liquid level sensor sends the second trigger signal due to a liquid level peak-valley error; When it is determined that the second liquid level sensor sends the second trigger signal due to a liquid level peak-valley error, the second trigger signal is invalidated.

3. The method for replenishing liquid in a wafer immersion cleaning device according to claim 2, wherein: The step of determining whether the second liquid level sensor sends the second trigger signal due to a liquid level peak-valley error when the second trigger signal sent by the second liquid level sensor is obtained includes: When the second trigger signal sent by the second liquid level sensor is obtained, calculating the duration of continuous sending of the second trigger signal by the second liquid level sensor within a preset time; Determining whether the continuous sending duration exceeds a time threshold; When the continuous sending time exceeds the time threshold, it is determined that the second trigger signal sent by the second liquid level sensor is not caused by a liquid level peak and trough error.

4. The method for replenishing liquid in a wafer immersion cleaning device according to claim 1, wherein: After the fourth step of determining that the inner immersion tank is completely replenished and the cleaning liquid overflows after the inner immersion tank is filled, so that the liquid level of the cleaning liquid in the liquid replenishment outer tank rises to the second height when the second trigger signal sent by the second liquid level sensor is obtained for the second time is completed, and before the fifth step of determining that the liquid level of the cleaning liquid in the liquid replenishment outer tank rises to the third height when the third trigger signal sent by the third liquid level sensor is obtained, so that the liquid replenishment device stops and the drain valve is opened, the following steps are further performed: The cleaning fluid is input into the fluid replenishment outer tank at a first flow rate, and the cleaning fluid in the fluid replenishment outer tank is discharged at a fourth flow rate to slow down the speed at which the cleaning fluid in the fluid replenishment outer tank continues to rise from the second height.

5. The method for replenishing liquid in a wafer immersion cleaning device according to claim 4, wherein: The fourth flow rate is smaller than the first flow rate.

6. The method for replenishing liquid in a wafer immersion cleaning device according to claim 1, wherein: The wafer immersion cleaning device refilling method further comprises the following steps: determining whether the liquid level of the cleaning fluid in the liquid replenishing outer tank is lower than a first height based on whether a first trigger signal sent by the first liquid level sensor is received; When it is determined that the first trigger signal sent by the first liquid level sensor is received, it is determined that the liquid level of the cleaning fluid in the liquid replenishing outer tank has reached the first height; otherwise, it is determined that the liquid level of the cleaning fluid in the liquid replenishing outer tank has not reached the first height, and an alarm is triggered.

7. The method for replenishing liquid in a wafer immersion cleaning device according to claim 1, wherein: The wafer immersion cleaning device refilling method further comprises the following steps: When determining to obtain the third trigger signal, determining whether the first liquid level sensor and / or the second liquid level sensor is invalid based on whether the first trigger signal and / or the second trigger signal is obtained; When the third trigger signal is obtained, the first trigger signal and / or the second trigger signal is not obtained, it is determined that the first liquid level sensor and / or the second liquid level sensor is invalid, and an alarm is triggered.

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