Concentration detection system for diluting chemicals for wafer cleaning and etching and control method

Abstract

The invention relates to a concentration detection system for diluting chemicals for wafer cleaning and etching and a control method. The system comprises a mixing barrel tank, a circulating pipeline, a concentration meter, a waste liquid tank and a cleaning pipeline. The input end of the circulating pipeline is communicated with the bottom of the mixing barrel groove, the output end of the circulating pipeline is communicated with the top of the mixing barrel groove, and a circulating pump is arranged on the circulating pipeline and matched with the circulating pipeline to circularly stir the chemical liquid medicine. And a detection branch is arranged between the first inlet end of the concentration meter and the circulating pipeline. And a liquid discharge pipe is arranged between the waste liquid tank and the outlet end of the concentration meter. The cleaning pipeline is communicated with the second inlet end of the concentration meter and is used for introducing ultrapure water and nitrogen into the concentration meter for cleaning and blow-drying. The measured chemical liquid medicine is directly discharged into the waste liquid tank, a cleaning pipeline is arranged, ultrapure water is used for flushing, nitrogen is used for drying the concentration meter, the chemical liquid medicine does not flow back to the mixing barrel tank any more, and secondary pollution of residual chemical liquid medicine and metal ions of the concentration meter to the chemical liquid medicine in the mixing barrel tank is avoided.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a concentration detection system and control method for diluting chemicals used in wafer cleaning and etching. Background Technology

[0002] In existing dilution systems for wafer cleaning and etching chemicals (such as hydrofluoric acid), the solution needs to be circulated and stirred in the main loop until homogeneous, and then sampled using a concentration meter after a fixed time. The measured solution is then returned to the mixing tank. If the concentration does not meet the standard, the above steps are repeated until the standard is met. However, because residual liquid often remains inside the concentration meter, metal ions in the sensor gradually diffuse and dissolve into the residual solution. During the circulation process, these metal ions are carried back to the tank, causing secondary contamination of the solution in the main tank. In addition, the system cannot accurately detect the content of metal ions in the circulation loop online. The only solution is to replace the concentration meter periodically to deal with sensor aging and contamination problems, resulting in high maintenance costs and severely restricting the stability and economy of the system. Summary of the Invention

[0003] The purpose of this invention is to provide a concentration detection system and control method for diluting chemicals used in wafer cleaning and etching. This system allows for the direct discharge of the measured chemical solution into a waste liquid tank, with a dedicated cleaning pipeline for rinsing with ultrapure water and drying the concentration meter with nitrogen. This eliminates the need to return the measured chemical solution to the mixing tank, effectively preventing secondary contamination of the chemical solution in the mixing tank by residual chemical solution and metal ions from the concentration meter. It also avoids prolonged contact between the chemical solution and the concentration meter, reducing the precipitation of metal ions and extending the service life of the concentration meter.

[0004] To achieve the above objectives, according to a first aspect of the present invention, a concentration detection system for diluting chemicals used in wafer cleaning and etching is provided, comprising:

[0005] Mixing tank;

[0006] A circulation pipeline is provided, with its inlet end connected to the bottom of the mixing tank and its outlet end connected to the top of the mixing tank. A circulation pump is installed on the circulation pipeline, which works in conjunction with the circulation pipeline to circulate and stir the chemical solution.

[0007] A concentration meter, wherein a detection branch is provided between the first inlet end of the concentration meter and the circulation pipeline;

[0008] Waste liquid tank, and a drain pipe is provided between the waste liquid tank and the outlet end of the concentration meter;

[0009] The cleaning pipeline is connected to the second inlet end of the concentration meter and is used to introduce ultrapure water and nitrogen gas into the concentration meter for cleaning and drying.

[0010] Optionally, a first drain pipe is provided between the waste liquid tank and the first inlet end of the concentration meter, and a second drain pipe is provided between the waste liquid tank and the first outlet end of the concentration meter.

[0011] Optionally, the concentration detection system for diluting chemicals used in wafer cleaning and etching further includes:

[0012] A sampling tank is provided, and a sampling tube is provided between the sampling tank and the second outlet end of the concentration meter.

[0013] Optionally, the inlet end of the cleaning pipeline is provided with a water pipe and an air pipe.

[0014] Optionally, a first valve is provided on the circulation pipeline, a second valve is provided on the detection branch, a third valve is provided on the first drain pipe, and a fourth valve is provided on the second drain pipe.

[0015] Optionally, a fifth valve is provided on the sampling tube, a sixth valve is provided on the water pipe, and a seventh valve is provided on the air pipe.

[0016] According to a second aspect of the present invention, a method for controlling the concentration detection system of chemicals diluted for wafer cleaning and etching is provided, comprising the following steps:

[0017] The circulation pump and the first valve are opened to allow the circulation pipeline to circulate and stir the mixing tank according to a preset cycle.

[0018] The concentration meter is controlled to detect the concentration of the chemical solution and to discharge waste chemical solution.

[0019] The cleaning pipeline is controlled to clean and dry the concentration meter after testing.

[0020] Optionally, controlling the concentration meter to detect the concentration of the chemical solution and discharging the chemical waste solution includes the following steps:

[0021] Control the first valve to close;

[0022] The second valve is opened to allow the chemical solution to enter the concentration meter for concentration detection.

[0023] After the test is completed, the second valve is closed and the third or fourth valve is opened to discharge the chemical waste liquid into the waste liquid tank.

[0024] Optionally, controlling the cleaning pipeline to clean and dry the concentration meter after testing includes the following steps:

[0025] The sixth valve is opened to allow ultrapure water to be introduced into the concentration meter for cleaning.

[0026] The sixth valve is closed and the seventh valve is opened to allow nitrogen gas to be introduced into the concentration meter for drying.

[0027] Optionally, the control method for the concentration detection system for diluting chemicals used in wafer cleaning and etching further includes the following steps:

[0028] After the chemical solution concentration meets the standard, the fifth valve is opened to allow the chemical solution to flow into the sampling tank for sampling.

[0029] The beneficial effects of this invention are as follows: by directly discharging the measured chemical solution into the waste liquid tank and setting up a special cleaning pipeline to rinse the concentration meter with ultrapure water and dry it with nitrogen, instead of returning the measured chemical solution to the mixing tank, the secondary pollution of the chemical solution in the mixing tank by the residual chemical solution and metal ions in the concentration meter is effectively avoided. At the same time, the long-term contact between the chemical solution and the concentration meter is avoided to reduce the precipitation of metal ions and extend the service life of the concentration meter.

[0030] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0031] Figure 1 This is a schematic structural diagram of a concentration detection system for diluting chemicals used in wafer cleaning and etching, according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic flowchart illustrating a control method for a concentration detection system for diluting chemicals used in wafer cleaning and etching, according to an embodiment of the present invention.

[0033] Figure 3 for Figure 2 A schematic flowchart of step S20;

[0034] Figure 4 for Figure 2 A schematic flowchart of step S30;

[0035] In the diagram: 1. Mixing tank; 2. Circulation pipeline; 21. Circulation pump; 22. First valve; 3. Concentration meter; 4. Waste liquid tank; 41. Drain pipe; 411. First drain pipe; 412. Second drain pipe; 413. Third valve; 414. Fourth valve; 5. Cleaning pipeline; 51. Water pipe; 52. Air pipe; 53. Sixth valve; 54. Seventh valve; 6. Detection branch; 61. Second valve; 7. Sampling tank; 71. Sampling tube; 72. Fifth valve. Detailed Implementation

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

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0039] Please see Figure 1 A preferred embodiment of this application illustrates a concentration detection system for diluting chemicals used in wafer cleaning and etching, comprising a mixing tank 1, a circulation pipeline 2, a concentration meter 3, a waste liquid tank 4, and a cleaning pipeline 5. The inlet of the circulation pipeline 2 is connected to the bottom of the mixing tank 1, and the outlet of the circulation pipeline 2 is connected to the top of the mixing tank 1. A circulation pump 21 is installed on the circulation pipeline 2, and the circulation pump 21 works in conjunction with the circulation pipeline 2 to circulate and stir the chemical solution. A detection branch 6 is provided between the first inlet of the concentration meter 3 and the circulation pipeline 2. A drain pipe 41 is provided between the waste liquid tank 4 and the outlet of the concentration meter 3. The cleaning pipeline 5 is connected to the second inlet of the concentration meter 3 and is used to introduce ultrapure water and nitrogen gas into the concentration meter 3 for cleaning and drying.

[0040] According to the embodiment of the present invention, by directly discharging the measured chemical solution into the waste liquid tank 4 and setting up a special cleaning pipeline 5 to rinse with ultrapure water and dry the concentration meter 3 with nitrogen, the measured chemical solution is no longer returned to the mixing tank 1. This effectively avoids secondary pollution of the chemical solution in the mixing tank 1 by the residual chemical solution and metal ions in the concentration meter 3, and at the same time avoids prolonged contact between the chemical solution and the concentration meter 3 to reduce the precipitation of metal ions and extend the service life of the concentration meter 3.

[0041] The following detailed description uses specific examples:

[0042] Specifically, see Figure 1 A first drain pipe 411 is provided between the waste liquid tank 4 and the first inlet end of the concentration meter 3, and a second drain pipe 412 is provided between the waste liquid tank 4 and the first outlet end of the concentration meter 3. After the concentration meter 3 measures the concentration of the chemical solution, the chemical solution waste liquid can be discharged through either the first drain pipe 411 or the second drain pipe 412.

[0043] Please see Figure 1 The concentration detection system also includes a sampling tank 7, and a sampling tube 71 is installed between the sampling tank 7 and the second outlet end of the concentration meter 3. When the concentration of the chemical solution reaches the standard, it is automatically guided to the sampling tank 7 for accurate sampling, providing standardized samples for subsequent laboratory or online quality control, while ensuring that the circulation pipeline 2 in the main tank system operates without interruption.

[0044] Please see Figure 1 The cleaning pipeline 5 is equipped with a water pipe 51 and an air pipe 52 at its inlet end, which are used to introduce ultrapure water and nitrogen gas respectively for cleaning and drying. With this configuration, a highly automated flushing-drying cycle can be achieved after the measurement is completed, thoroughly removing residual chemical solutions in the concentration meter 3 and quickly drying it, reducing the amount of manual maintenance work.

[0045] Further, please see Figure 1 A first valve 22 is installed on the circulation pipeline 2, a second valve 61 is installed on the detection branch 6, a third valve 413 is installed on the first drain pipe 411, and a fourth valve 414 is installed on the second drain pipe 412. A fifth valve 72 is installed on the sampling pipe 71, a sixth valve 53 is installed on the water pipe 51, and a seventh valve 54 is installed on the vent pipe 52.

[0046] Please see Figure 2 The present invention also provides a control method for a concentration detection system for dilution of chemicals used in wafer cleaning and etching, comprising the following steps:

[0047] Step S10: Control the circulation pump 21 and the first valve 22 to open so that the circulation pipeline 2 cooperates with the mixing tank 1 to circulate and stir according to the preset cycle;

[0048] Step S20: Control the concentration meter 3 to detect the concentration of the chemical solution and discharge the chemical waste liquid;

[0049] Step S30: Control the cleaning pipeline 5 to clean and dry the concentration meter 3 after testing.

[0050] First, control the circulation pump 21 and the first valve 22 to open, so that the chemical solution in the mixing tank 1 is circulated and stirred according to the preset cycle; then control the concentration meter 3 to perform online concentration detection and start waste liquid discharge after measurement; finally, control the cleaning pipeline 5 to sequentially flush with ultrapure water and blow dry with nitrogen, so as to realize the automated closed-loop control of the entire mixing-measurement-cleaning process.

[0051] Please see Figure 3 Step S20 includes the following steps:

[0052] Step S201: Close the first valve 22;

[0053] Step S202: Control the second valve 61 to open so that the chemical solution enters the concentration meter 3 for concentration detection;

[0054] Step S203: After the test is completed, control the second valve 61 to close and the third valve 413 or the fourth valve 414 to open and discharge the chemical waste liquid into the waste liquid tank 4.

[0055] In step S20, the first valve 22 is closed to cut off the main circulation path, and then the second valve 61 is opened to introduce the chemical solution into the concentration meter 3 for measurement. After the measurement is completed, the second valve 61 is closed, and the third or fourth valve 414 is opened to discharge the waste liquid into the waste liquid tank 4 respectively, so as to realize the safe switching of the flow path before and after the measurement and the directional discharge of waste liquid.

[0056] Please see Figure 4 Step S30 includes the following steps:

[0057] Step S301: Control the sixth valve 53 to open so that ultrapure water can be introduced into the concentration meter 3 for cleaning;

[0058] Step S302: Control the sixth valve 53 to close and the seventh valve 54 to open so that nitrogen gas can be introduced into the concentration meter 3 for drying.

[0059] In step S30, the sixth valve 53 is first opened to introduce ultrapure water into the concentration meter 3 for rinsing. After rinsing is completed, the sixth valve 53 is closed and the seventh valve 54 is opened to introduce nitrogen gas for drying, achieving efficient switching between cleaning and drying, and ensuring that the concentration meter 3 is clean and free of residual liquid before the next measurement.

[0060] Furthermore, the control method also includes the following steps:

[0061] After the chemical solution concentration test meets the standard, the fifth valve 72 is opened to allow the chemical solution to flow into the sampling tank 7 for sampling.

[0062] Once the concentration of the chemical solution meets the standard, the fifth valve 72 is opened, automatically introducing the qualified chemical solution into the sampling tank 7 for sampling. This provides immediate samples for quality traceability and subsequent analysis, without affecting the continuous operation of the main system circulation.

[0063] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0064] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A concentration detection system for diluting chemicals used in wafer cleaning and etching, characterized in that, include: Mixing tank; A circulation pipeline is provided, with its inlet end connected to the bottom of the mixing tank and its outlet end connected to the top of the mixing tank. A circulation pump is installed on the circulation pipeline, which works in conjunction with the circulation pipeline to circulate and stir the chemical solution. A concentration meter, wherein a detection branch is provided between the first inlet end of the concentration meter and the circulation pipeline; Waste liquid tank, and a drain pipe is provided between the waste liquid tank and the outlet end of the concentration meter; The cleaning pipeline is connected to the second inlet end of the concentration meter and is used to introduce ultrapure water and nitrogen gas into the concentration meter for cleaning and drying.

2. The concentration detection system for diluting chemicals used in wafer cleaning and etching according to claim 1, characterized in that, A first drain pipe is provided between the waste liquid tank and the first inlet end of the concentration meter, and a second drain pipe is provided between the waste liquid tank and the first outlet end of the concentration meter.

3. The concentration detection system for diluting chemicals used in wafer cleaning and etching according to claim 1, characterized in that, Also includes: A sampling tank is provided, and a sampling tube is provided between the sampling tank and the second outlet end of the concentration meter.

4. The concentration detection system for diluting chemicals used in wafer cleaning and etching according to claim 3, characterized in that, The inlet end of the cleaning pipeline is equipped with a water pipe and an air pipe.

5. The concentration detection system for diluting chemicals used in wafer cleaning and etching according to claim 2, characterized in that, A first valve is installed on the circulation pipeline, a second valve is installed on the detection branch, a third valve is installed on the first drain pipe, and a fourth valve is installed on the second drain pipe.

6. The concentration detection system for diluting chemicals used in wafer cleaning and etching according to claim 4, characterized in that, The sampling tube is equipped with a fifth valve, the water pipe is equipped with a sixth valve, and the air pipe is equipped with a seventh valve.

7. A control method for a concentration detection system for dilution of chemicals used in wafer cleaning and etching as described in any one of claims 1 to 6, characterized in that, The steps include: The circulation pump and the first valve are opened to allow the circulation pipeline to circulate and stir the mixing tank according to a preset cycle. The concentration meter is controlled to detect the concentration of the chemical solution and to discharge waste chemical solution. The cleaning pipeline is controlled to clean and dry the concentration meter after testing.

8. The control method for a concentration detection system for dilution of chemicals used in wafer cleaning and etching according to claim 7, characterized in that, The process of controlling the concentration meter to detect the concentration of the chemical solution and discharging the waste chemical solution includes the following steps: Control the first valve to close; The second valve is opened to allow the chemical solution to enter the concentration meter for concentration detection. After the test is completed, the second valve is closed and the third or fourth valve is opened to discharge the chemical waste liquid into the waste liquid tank.

9. The control method for a concentration detection system for diluting chemicals used in wafer cleaning and etching according to claim 7, characterized in that, The process of controlling the cleaning pipeline to clean and dry the concentration meter after testing includes the following steps: The sixth valve is opened to allow ultrapure water to be introduced into the concentration meter for cleaning. The sixth valve is closed and the seventh valve is opened to allow nitrogen gas to be introduced into the concentration meter for drying.

10. The control method for a concentration detection system for diluting chemicals used in wafer cleaning and etching according to claim 7, characterized in that, It also includes the following steps: After the chemical solution concentration meets the standard, the fifth valve is opened to allow the chemical solution to flow into the sampling tank for sampling.

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