Device and method for controlling HF (hydrogen fluoride) concentration of cleaning tank of silicon wafer tank
By designing an HF concentration control device including an HF liquid tank, an ultrapure water inlet pipe, an HF liquid replenishment pipe, a liquid replenishing pump, a concentration meter and a PLC controller, the problems of unstable concentration and poor compatibility of the traditional Chinese medicine liquid in the prior art are solved, and automatic control and optimal cleaning effect of the liquid concentration are achieved.
Patent Information
- Application Number
- CN202411644679.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-18
- Publication Date
- 2025-03-18
AI Technical Summary
The prior art is difficult to achieve compatibility of factory liquids of different concentrations on the same preparation machine, and the liquid dispensing concentration error is large, which has the problem of inaccurate liquid dispensing.
A silicon wafer tank cleaning tank HF concentration control device is designed, including an HF liquid tank, an ultra-pure water inlet pipe, an HF liquid replenishment pipe, a liquid replenishment pump, a concentration meter and a PLC controller. Through the cooperation of these components, automatic control of the concentration of HF liquid is achieved.
It solves the problem of unstable HF concentration in the cleaning tank, ensures that the concentration of the medicine liquid reaches the best cleaning effect, thereby effectively cleaning the silicon wafer.
Smart Images
Figure CN119645133A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a HF concentration control device for a silicon wafer tank cleaning tank and a control method thereof. Background Art
[0002] Wafer cleaning in the semiconductor manufacturing process refers to the process of removing contaminants and self-oxides on the wafer surface by physical or chemical methods before oxidation, photolithography, epitaxy, diffusion and other processes to obtain a wafer surface that meets the cleanliness requirements.
[0003] The process does not have strict requirements on concentration control. For liquid medicines with relatively large dosage, they are prepared before entering the machine. After the liquid medicines are prepared to the required concentration, they are directly pumped from the plant to the process tank. The liquid level sensor of the process tank is used for constant volume and quantity. This method is generally used for the preparation of base liquids with relatively large dosage in the process.
[0004] For non-base liquid preparation and for those with higher concentration control requirements, a buffer tank is usually set at the machine end. The volume and quantity are determined by the liquid level in the buffer tank, and a fixed amount of liquid medicine is injected into the base liquid by gravity. The amount of liquid medicine injected each time is the same calibrated volume. For those with higher capacity control requirements, a metering pump is usually used to pump and inject the liquid medicine.
[0005] The current method of preparing cleaning machine liquid makes it difficult to achieve compatibility of multiple factory liquids of different concentrations on the same preparation machine. Even if compatibility is achieved, re-calibration of capacity and other operations are required, and the concentration error of the prepared liquid is large, resulting in inaccurate preparation. Summary of the invention
[0006] The present invention mainly solves the deficiencies in the prior art and provides a HF concentration control device for a silicon wafer tank cleaning tank and a control method thereof, which has the advantages of compact structure, good operation stability and good effect. The problem of unstable HF concentration in the cleaning tank is solved. The concentration of the liquid in the cleaning tank reaches the best cleaning effect, thereby achieving the purpose of cleaning the silicon wafer.
[0007] The above technical problems of the present invention are mainly solved by the following technical solutions: A HF concentration control device for a silicon wafer tank cleaning tank comprises an HF solution tank, wherein an ultrapure water inlet pipe and an HF solution replenishing pipe connected to the HF solution tank are arranged on the side of the HF solution tank, a liquid adding pump is arranged on the HF solution replenishing pipe, a concentration meter is arranged in the HF solution tank, and a PLC controller is arranged between the concentration meter and the liquid adding pump.
[0008] Preferably, a measuring cylinder connected to the HF liquid replenishing tube is provided between the HF liquid tank and the liquid adding pump.
[0009] Preferably, the lower end of the HF liquid tank is provided with a drainage hole. During the silicon wafer cleaning process, the drainage hole is plugged and plugged with liquid storage.
[0010] The control method of the HF concentration control device of the silicon wafer tank cleaning tank includes the following operating steps: Step 1: Connect the HF solution replenishing pipe on the HF solution tank to the factory supply.
[0011] Step 2: Inject the HF solution supplied by the plant service end into the measuring cylinder through the liquid adding pump and then send it into the HF liquid tank through the HF liquid filling tube.
[0012] Step 3: Add ultrapure water into the HF solution tank through the ultrapure water inlet pipe.
[0013] Step 4: The concentration meter in the HF solution tank measures the HF concentration in the HF solution tank.
[0014] Step 5: The measured HF concentration is fed back to the PLC controller through the signal line.
[0015] Step 6: Through the negative feedback regulation of the PLC controller, the HF concentration in the HF solution tank is automatically controlled.
[0016] Preferably, the mass fraction of the HF solution at the plant service end is 30% and the temperature is 22°C.
[0017] Preferably, when the concentration meter measures that the HF concentration in the HF liquid tank is lower than the set value, the liquid HF is continuously pumped in by the liquid adding pump until the set concentration is reached.
[0018] Preferably, when the HF concentration in the HF solution tank is too high, ultrapure water at 50° C. is input into the HF solution tank through the ultrapure water inlet pipe to reduce the HF concentration until the set concentration is reached.
[0019] When the equipment is working, when the HF solution reaches the HF solution tank, it reaches the set concentration value of 1.5%. By adjusting the amount of HF solution and ultrapure water added, the HF concentration in the HF solution tank is maintained, and the purpose of cleaning the silicon wafer is achieved under the immersion cleaning of HF solution at a certain temperature.
[0020] The present invention can achieve the following effects: The present invention provides a HF concentration control device for a silicon wafer tank cleaning tank and a control method thereof, which has the advantages of compact structure, good operation stability and good effect compared with the prior art. The problem of unstable HF concentration in the cleaning tank is solved. The concentration of the liquid in the cleaning tank reaches the best cleaning effect, thereby achieving the purpose of cleaning silicon wafers. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1It is a structural schematic diagram of the present invention.
[0022] In the figure: PLC controller 1, measuring cylinder 2, concentration meter 3, HF solution tank 4, drainage hole 5, ultrapure water inlet pipe 6, HF solution replenishing pipe 7, and liquid adding pump 8. DETAILED DESCRIPTION
[0023] The technical solution of the invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.
[0024] Example: Figure 1 As shown, a HF concentration control device for a silicon wafer tank cleaning tank comprises an HF liquid tank 4, and a drainage hole 5 is provided at the lower end of the HF liquid tank 4. During the silicon wafer cleaning process, the drainage hole 5 is plugged and plugged to store liquid. An ultrapure water inlet pipe 6 and an HF liquid replenishing pipe 7 connected to the HF liquid tank 4 are provided on the side of the HF liquid tank 4, and a liquid adding pump 8 is provided on the HF liquid replenishing pipe 7. A measuring cylinder 2 connected to the HF liquid replenishing pipe 7 is provided between the HF liquid tank 4 and the liquid adding pump 8. A concentration meter 3 is provided in the HF liquid tank 4, and a PLC controller 1 is provided between the concentration meter 3 and the liquid adding pump 8.
[0025] The control method of the HF concentration control device of the silicon wafer tank cleaning tank includes the following operating steps: Step 1: The HF solution refilling pipe 7 on the HF solution tank 4 is connected to the factory supply. The mass fraction of the HF solution at the factory end is 30% and the temperature is 22°C.
[0026] Step 2: The HF solution supplied by the factory service end is injected into the measuring cylinder 2 through the liquid adding pump 8 and then sent into the HF liquid tank 4 through the HF liquid replenishing tube 7.
[0027] Step 3: The ultrapure water inlet pipe 6 adds ultrapure water into the HF solution tank 4.
[0028] Step 4: The concentration meter 3 in the HF solution tank 4 measures the HF concentration in the HF solution tank 4; Step 5: The measured HF concentration is fed back to the PLC controller 1 through the signal line.
[0029] Step 6: Through the negative feedback regulation of the PLC controller 1, the HF concentration in the HF solution tank 4 is automatically controlled.
[0030] When the concentration meter 3 measures that the HF concentration in the HF liquid tank 4 is lower than the set value, the liquid HF is continuously pumped in by the liquid adding pump 8 until the set concentration is reached.
[0031] When the HF concentration in the HF solution tank 4 is too high, ultrapure water at 50° C. is input into the HF solution tank 4 through the ultrapure water inlet pipe 6 to reduce the HF concentration until it reaches the set concentration.
[0032] In summary, the HF concentration control device and control method for the silicon wafer tank cleaning tank have the advantages of compact structure, good operation stability and good effect. The problem of unstable HF concentration in the cleaning tank is solved. The concentration of the liquid in the cleaning tank reaches the best cleaning effect, thereby achieving the purpose of cleaning the silicon wafer.
[0033] The above description is only a specific embodiment of the present invention, but the structural features of the present invention are not limited thereto. Any changes or modifications made by any technician in the field of the present invention are included in the patent scope of the present invention.
Claims
1. A HF concentration control device for a silicon wafer cleaning tank, characterized in that: The invention comprises an HF liquid tank (4), wherein an ultrapure water inlet pipe (6) and an HF liquid replenishing pipe (7) connected to the HF liquid tank (4) are provided on the side of the HF liquid tank (4), a liquid adding pump (8) is provided on the HF liquid replenishing pipe (7), a concentration meter (3) is provided in the HF liquid tank (4), and a PLC controller (1) is provided between the concentration meter (3) and the liquid adding pump (8).
2. The HF concentration control device for a silicon wafer tank cleaning tank according to claim 1, characterized in that: A measuring cylinder (2) connected to the HF liquid replenishing tube (7) is provided between the HF liquid tank (4) and the liquid adding pump (8).
3. The HF concentration control device for a silicon wafer tank cleaning tank according to claim 1, characterized in that: The lower end of the HF liquid tank (4) is provided with a drainage hole (5); during the silicon wafer cleaning process, the drainage hole (5) is plugged and plugged with liquid storage.
4. A control method for the HF concentration control device of the silicon wafer tank cleaning tank according to claim 2, characterized in that The steps are as follows: Step 1: The HF solution refilling pipe (7) on the HF solution tank (4) is connected to the factory supply; Step 2: The HF solution supplied by the factory service end is injected into the measuring cylinder (2) through the liquid adding pump (8) and then sent into the HF liquid tank (4) through the HF liquid filling pipe (7); Step 3: The ultrapure water inlet pipe (6) adds ultrapure water into the HF solution tank (4); Step 4: The concentration meter (3) in the HF solution tank (4) measures the HF concentration in the HF solution tank (4); Step 5: The measured HF concentration is fed back to the PLC controller via the signal line (1); Step 6: Through the negative feedback regulation of the PLC controller (1), the HF concentration in the HF solution tank (4) is automatically controlled.
5. The control method of the HF concentration control device for the silicon wafer tank cleaning tank according to claim 4, characterized in that: The mass fraction of HF solution at the plant service end is 30% and the temperature is 22°C.
6. The control method of the HF concentration control device for the silicon wafer tank cleaning tank according to claim 5, characterized in that: When the concentration meter (3) measures that the HF concentration in the HF liquid tank (4) is lower than the set value, the liquid HF is continuously pumped in by the liquid adding pump (8) until the set concentration is reached.
7. The control method of the HF concentration control device for the silicon wafer tank cleaning tank according to claim 5, characterized in that: When the HF concentration in the HF solution tank (4) is too high, ultrapure water at 50° C. is input into the HF solution tank (4) through the ultrapure water inlet pipe (6) to reduce the HF concentration until the set concentration is reached.