Sample introduction and tail gas treatment system for silane gas analysis

Abstract

The utility model relates to the technical field of silane gas analysis, and provides a sample introduction and tail gas treatment system for silane gas analysis, which is used for sample introduction of silane gas and is beneficial to improvement of detection repeatability and accuracy. The system comprises a six-way valve and a purge gas input pipe, and further comprises a sample gas inlet pipe, a carrier gas inlet pipe, a quantitative ring and a tail gas output pipe which are respectively connected with the six-way valve, the system further comprises a tail gas absorption tank; the tail gas output pipe comprises an upstream pipe section and a downstream pipe section, and the purge gas input pipe is communicated with the tail gas absorption tank through the downstream pipe section of the tail gas output pipe; the sample gas inlet pipe is provided with a pressure regulating valve and a pressure sensor, and the pressure regulating valve and the pressure sensor are respectively in communication connection with the pressure controller; a carrier gas pressure reducing valve and a flow controller for adjusting the carrier gas flow in the carrier gas inlet pipe are arranged on the carrier gas inlet pipe; and the upstream pipe section of the tail gas output pipe is provided with a flow meter and a one-way valve.

Description

Technical Field

[0001] The utility model relates to the technical field of silane gas analysis, in particular to a sampling and tail gas treatment system for silane gas analysis. Background Art

[0002] Electronic specialty gases are a key raw material in the semiconductor industry, and are indispensable in nearly every step of the production process. As the semiconductor industry continues to evolve toward higher performance and higher integration, the purity requirements for these gases are increasing, and so are the analytical techniques used to analyze them.

[0003] Silanes, a type of electronic specialty gas, have become crucial in semiconductor microelectronics processing. Almost all modern advanced integrated circuit production lines require silanes. The purity of silane gases significantly impacts device performance and yield, leading to increasing precision requirements for silane gas detection. During gas chromatography, pressure fluctuations at the sample inlet and outlet impact detection accuracy and repeatability. Furthermore, the silica powder produced by contact between silane gas and air can contaminate and potentially clog pipelines, necessitating an exhaust gas treatment system to completely absorb any remaining silane gas.

[0004] Most existing analytical techniques rely on direct sampling, which results in significant pressure fluctuations with each injection, leading to low detection accuracy. Furthermore, if exhaust gas is not promptly or incompletely treated, the resulting silica powder produced when it comes into contact with air can clog the outlet pipe, hindering gas flow and affecting instrument data repeatability and reproducibility, while also posing a safety hazard. Utility Model Content

[0005] In response to at least one shortcoming of the prior art, the present invention provides a sampling and exhaust gas treatment system for silane gas analysis. The system is used to sample silane gas, which is beneficial to the stability of the gas pipeline pressure and flow rate during the sampling process of silane gas, thereby helping to improve the repeatability and accuracy of detection.

[0006] In order to achieve its purpose, the present invention provides the following technical solutions:

[0007] The utility model provides a sampling and tail gas treatment system for silane gas analysis, comprising a six-way valve and a purge gas input pipe, and also comprising a sample gas inlet pipe, a carrier gas inlet pipe, a quantitative loop and a tail gas output pipe respectively connected to the six-way valve; the system also comprises a tail gas absorption tank;

[0008] The tail gas output pipe includes an upstream pipe section and a downstream pipe section that are interconnected along the airflow direction, and the purge gas input pipe is connected to the tail gas absorption tank through the downstream pipe section of the tail gas output pipe;

[0009] The sample gas inlet pipe is provided with a pressure regulating valve and a pressure sensor, and the pressure regulating valve and the pressure sensor are respectively connected to the pressure controller for communication;

[0010] The carrier gas inlet pipe is provided with a carrier gas pressure reducing valve and a flow controller for adjusting the carrier gas flow rate in the carrier gas inlet pipe;

[0011] The upstream pipe section of the tail gas output pipe is provided with a flow meter and a one-way valve.

[0012] Furthermore, the quantitative loop can be switched between a first communication state and a second communication state by opening and closing the six-way valve;

[0013] When the quantitative loop is in the first communication state, the inlet of the quantitative loop is connected to the carrier gas inlet pipe, and the outlet of the quantitative loop is connected to the downstream separation and detection system;

[0014] When the quantitative loop is in the second connected state, the sample gas inlet pipe, the quantitative loop, and the upstream pipe section of the exhaust gas output pipe are connected in sequence, and the carrier gas inlet pipe is connected to the downstream separation and detection system through a connecting pipe.

[0015] Preferably, the inner cavity of the exhaust gas absorption tank includes an absorption liquid holding area, and a gas diffusion element for diffusing the exhaust gas into the absorption liquid holding area is provided in the absorption liquid holding area. The gas diffusion element is connected to the outlet end of the downstream pipe section of the exhaust gas output pipe through an exhaust gas inlet pipe, and an anti-backflow ball is provided on the exhaust gas inlet pipe.

[0016] Preferably, the gas diffusion element is provided with a gas inlet and an exhaust gas collecting chamber, the gas inlet is communicated with the exhaust gas inlet pipe and the exhaust gas collecting chamber respectively, and the exhaust gas collecting chamber has a plurality of gas outlet holes.

[0017] Preferably, the multiple air outlet holes of the exhaust gas collecting chamber are distributed around the circumference and at the bottom of the exhaust gas collecting chamber.

[0018] Preferably, the diameter of the gas inlet on the gas inlet side is larger than the diameter of the gas outlet side;

[0019] The tail gas collecting chamber has an inner diameter that is narrow at first and then wide along the gas flow direction.

[0020] Preferably, an air resistance is provided between the flow meter and the one-way valve.

[0021] Furthermore, a sample gas pressure reducing valve is provided on the sample gas inlet pipe.

[0022] Furthermore, the inner cavity of the tail gas absorption tank is provided with a drain port, the drain port is connected to a drain pipeline, and a drain valve is provided on the drain pipeline.

[0023] Furthermore, a purge valve is provided on the purge gas input pipe.

[0024] The technical solution provided by the utility model has the following beneficial effects:

[0025] The utility model provides a pressure regulating valve and a pressure sensor on the sample gas inlet pipe, and the pressure regulating valve and the pressure sensor are respectively communicated with the pressure controller; the carrier gas inlet pipe is provided with a carrier gas pressure reducing valve and a flow controller for adjusting the carrier gas flow rate in the carrier gas inlet pipe, which is beneficial to the stability of the gas pipeline pressure and flow during the silane gas sampling process, and is beneficial to improving the detection repeatability and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic diagram of a sampling and tail gas treatment system for silane gas analysis in one embodiment;

[0027] Figure 2 Schematic diagram of the structure of a gas diffusion element in one embodiment. DETAILED DESCRIPTION

[0028] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with the embodiments. It should be understood that the following embodiments are only for a better understanding of the present invention and do not mean that the present invention is limited to the following embodiments.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs. Directional terms such as upper, lower, front, rear, top, and bottom mentioned or that may be mentioned in this specification are defined relative to the structures shown in the accompanying drawings. They are relative concepts and may therefore change accordingly depending on their different positions and different usage conditions. The words "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively. In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0030] The present invention is a solution formed by improving the existing silane gas analysis sampling and exhaust gas treatment system. Specifically, the system of the present invention, like the system in the prior art, includes a six-way valve 24 and a purge gas input pipe 15, as well as a sample gas inlet pipe 16, a carrier gas inlet pipe 17, a quantitative loop 14, and an exhaust gas output pipe 18, respectively connected to the six-way valve 24; the quantitative loop 14 is switched between different connection states by opening and closing the six-way valve 24. The six-way valve 24 is a component well known in the art, and its structure and working process are conventional technologies mastered by those skilled in the art, and will not be described in detail.

[0031] One of the system improvements of the present invention is that the system also includes a tail gas absorption tank 11 for absorbing the tail gas output by the tail gas output pipe 18; the tail gas output pipe 18 includes an upstream pipe section 27 and a downstream pipe section 26 that are interconnected along the air flow direction, and the purge gas input pipe 15 is connected to the tail gas absorption tank 11 through the downstream pipe section 26 of the tail gas output pipe 18, that is, the downstream pipe section 26 of the tail gas output pipe 18 is connected between the purge gas input pipe 15 and the tail gas absorption tank 11; a sample gas pressure reducing valve 1 is provided on the sample gas inlet pipe 16, and a pressure regulating valve 2 and a pressure sensor 3 are also provided, and the pressure regulating valve 2 and the pressure sensor 3 are connected. The sensors 3 are each in communication with a pressure controller (not shown). Specifically, the pressure sensors 3 monitor the pressure within the sample gas inlet pipe 16 and feed back the pressure detection result to the pressure controller. The pressure controller adjusts the opening of the pressure regulating valve 2 based on the comparison between the obtained pressure detection result and a preset value, thereby maintaining the sample gas inlet pressure within the sample gas inlet pipe 16 at the preset pressure, that is, maintaining the sample gas inlet pressure within the sample gas inlet pipe 16 stable. The pressure regulating valve 2 can be a solenoid pressure regulating valve 2. The pressure controller and the pressure sensor 3 can be integrated or separately provided. The carrier gas inlet pipe 17 is provided with a carrier gas pressure reducing valve 4 and a flow controller 5 for regulating the carrier gas flow within the carrier gas inlet pipe 17. The flow controller 5 maintains the carrier gas flow within the carrier gas inlet pipe 17 at the preset flow rate, thereby facilitating the flow stability of the downstream separation and detection system during the sampling process. The upstream pipe section 27 of the exhaust gas output pipe 18 is provided with a flow meter 7 and a one-way valve 9. The flow meter 7 can be, for example, a float flow meter, which can further monitor the exhaust gas flow in the exhaust gas output pipe 18. The above improvements help ensure the stability of the sample gas injection pressure and the flow rate of the sample gas injected into the separation and detection system, thereby improving the repeatability and accuracy of silane gas detection and analysis. Specifically, the carrier gas can be an inert gas such as high-purity helium or high-purity nitrogen. The separation and detection system 25 can be, for example, a conventional separation and detection instrument with a chromatographic column, as is conventional in the art.

[0032] The six-way valve 24 specifically includes six ports, namely port ①, port ②, port ③, port ④, port ⑤ and port ⑥. Specifically, the sample gas inlet pipe 16 is connected to port ①, the exhaust gas output pipe 18 is connected to port ②, the quantitative loop 14 is connected between port ③ and port ⑥, port ④ is used to connect to the downstream separation and detection system 25, and the carrier gas inlet pipe 17 is connected to port ⑤. By switching the six-way valve 24 on and off, the quantitative loop 14 can be switched between the first connected state and the second connected state. Specifically, when the quantitative loop 14 is in the first connected state, that is, when the six-way valve 24 is open, the carrier gas inlet pipe 17, the quantitative loop 14 and the downstream separation and detection system 25 are connected in sequence; when the quantitative loop 14 is in the second connected state, that is, when the six-way valve 24 is closed, see Figure 1 In this state, the sample gas inlet pipe 16, the quantitative loop 14, and the upstream pipe section 27 of the tail gas output pipe 18 are connected in sequence, and the carrier gas inlet pipe 17 is connected to the downstream separation and detection system 25 through a connecting pipe.

[0033] The inner cavity of the exhaust gas absorption tank 11 is provided with an absorption liquid holding area 20, in which the exhaust gas output from the exhaust gas output pipe 18 contacts the absorption liquid and is absorbed by the absorption liquid. The absorption liquid is, for example, an alkaline solution with a concentration of 10wt%-20wt%, such as an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, or other absorption liquid commonly used in the art. The amount of absorption liquid added is, for example, 1 / 3-2 / 3 of the volume of the exhaust gas absorption tank 11. A gas diffusion element 12 is provided in the absorption liquid holding area 20 for diffusing the exhaust gas into the absorption liquid holding area 20. The gas diffusion element 12 is connected to the gas outlet end of the downstream pipe section 26 of the exhaust gas output pipe 18 through the exhaust gas inlet pipe 19. The exhaust gas inlet pipe 19 is provided with an anti-backflow ball 10 to prevent the absorption liquid from being backflowed into the sample pipeline. Preferably, the gas diffuser element 12 is provided with a gas inlet 21 and an exhaust gas collection chamber 22, wherein the gas inlet 21 is connected to the exhaust gas inlet pipe 19 and the exhaust gas collection chamber 22, respectively. The exhaust gas collection chamber 22 is provided with a plurality of gas outlet holes 23, specifically, for example, located at the bottom of the exhaust gas collection chamber 22. Exhaust gas enters the exhaust gas collection chamber 22 of the gas diffuser element 12 and diffuses into the absorption liquid in the absorption liquid holding area 20 through each gas outlet hole 23. More preferably, the plurality of gas outlet holes 23 of the exhaust gas collection chamber 22 are distributed around the circumference and at the bottom of the exhaust gas collection chamber 22. Preferably, the diameter of the gas inlet 21 on the gas inlet side is larger than the diameter of the gas outflow side, for example, it is funnel-shaped, which can stabilize the gas flow rate; the exhaust gas collecting chamber 22 has an overall inner diameter that is narrow at first and then wide along the flow direction of the gas, that is, narrow at the front and wide at the back. Specifically, the inner diameter of the exhaust gas collecting chamber 22 close to the gas inlet 21 is smaller than the inner diameter of the exhaust gas collecting chamber 22 with the outlet hole 23, which is conducive to more efficient and sufficient absorption of the exhaust gas by the absorption liquid.

[0034] Furthermore, a float flowmeter 7 and a one-way valve 9 are provided in the upstream section 27 of the exhaust gas output pipe 18. An air block 8 is provided between the float flowmeter 7 and the one-way valve 9. This facilitates further monitoring of the exhaust gas flow in the exhaust gas output pipe 18 and ensures that the silane exhaust gas enters the exhaust gas absorption tank 11 at a stable flow rate. The air block 8 can be a conventional air block element in the art. In some examples, the opening pressure of the one-way valve 9 is 1 psi to prevent downstream gas from entering the sample gas pipeline and contaminating the sample gas.

[0035] Furthermore, the inner cavity of the tail gas absorption tank 11 is provided with a drain port for discharging the absorption liquid that has absorbed the tail gas. The drain port is connected to a drain pipeline, and a drain valve 13 is provided on the drain pipeline.

[0036] The purge gas flowing in the purge gas inlet pipe 15 is, for example, an inert gas such as nitrogen or helium. A purge valve 6 is provided on the purge gas inlet pipe 15. The purge gas is introduced through the purge gas inlet pipe 15 to purge the downstream pipe section 26 of the exhaust gas output pipe 18 and the pipeline and anti-backflow ball 10 in the exhaust gas absorption tank 11 to ensure that there is no sample gas or air residue in the pipeline and the tank body.

[0037] The system provided by the utility model can achieve the stabilization of the pressure of the sample gas at a set value during the injection process, effectively avoiding inaccurate detection results caused by unstable injection pressure, and is conducive to improving the repeatability and accuracy of sample gas detection.

[0038] The utility model absorbs silane tail gas safely and fully through the tail gas absorption tank 11, which not only reduces pollution to the environment and improves safety, but also prevents powder generated by silane combustion from clogging the gas path and affecting the injection pressure.

[0039] Unless otherwise specified, the various components of the apparatus involved in the present invention may be conventional components or devices having corresponding functions in the art. For example, the six-way valve 24, the separation detection system 25, the flow controller 5, the pressure sensor 3, etc. are all conventional components or devices in the art and will not be described in detail. This article mainly introduces the improvements made. Any parts not specifically specified are conventional technologies in the art for silane gas analysis and sampling and exhaust gas treatment systems and will not be described in detail.

[0040] The following is an illustrative description of the workflow of the silane gas analysis sampling and tail gas treatment system of the present invention through specific application examples.

[0041] Application Example 1

[0042] Taking monosilane as an example, the following steps are used Figure 1-2 The silane gas analysis sampling and tail gas treatment system shown in the figure is used to analyze monosilane samples. Figure 1-2 The description of the system shown is given above and will not be repeated here. Figure 1 The six-way valve 24 in the state shown is in the initial closed state. At this time, the carrier gas inlet pipe 17 connected to the port ⑤ of the six-way valve is connected to the separation detection system 25 connected to the port ④ of the six-way valve through the connecting pipe, and the sample gas inlet pipe 16, the quantitative ring 14, and the upstream pipe section 27 of the exhaust gas output pipe 18 are connected in sequence.

[0043] The first step is to ensure that there is sufficient absorption liquid inside the tail gas absorption tank 11;

[0044] The second step is to open the carrier gas pressure reducing valve 4 and adjust its outlet pressure to 6 bar, and control the carrier gas flow rate to 40 ml / min through the flow controller 5;

[0045] The third step is to open the purge valve 6 and pass the purge gas for 40-50 minutes to ensure that there is no air residue in the downstream pipe section 26 of the tail gas output pipe 18, the pipeline in the tail gas absorption tank 11 and the anti-backflow ball 10;

[0046] Step 4: Open the sample gas pressure reducing valve 1 and adjust its outlet pressure to 0.8-1.2 bar;

[0047] Step 5: Monitor the pressure in the sample gas inlet pipe 16 through the pressure sensor 3 and adjust the pressure regulating valve 2 through the pressure controller so that the pressure in the sample gas inlet pipe 16 is stabilized at 0.8 bar.

[0048] Step 6: After the sample gas is introduced through the sample gas inlet pipe 16 for 30 seconds, the sample detection and analysis method is run, and the six-way valve 24 is opened. At this time, the connection state of the quantitative loop 14 is switched, and the quantitative loop 14 is no longer connected to the sample gas inlet pipe 16 and the exhaust gas output pipe 18. The carrier gas inlet pipe 17, the quantitative loop 14 and the separation and detection system 25 are connected in sequence;

[0049] The carrier gas in the carrier gas inlet pipe 17 pushes the sample gas in the quantitative loop 14 into the separation and detection system 25 to complete the detection;

[0050] Step 7: After the six-way valve 24 is opened in step 6, the sample gas pressure reducing valve 1 is closed to stop the injection;

[0051] Step 8: Open the purge valve 6 and introduce purge gas into the purge gas inlet pipe 15 for 40-50 minutes to ensure that no sample gas remains in the downstream pipe section 26 of the tail gas output pipe 18, the pipeline in the tail gas absorption tank 11, and the anti-backflow ball 10;

[0052] In the ninth step, the drain valve 13 is opened to drain the absorption liquid that has absorbed the tail gas and to replace it with new absorption liquid. The above steps are repeated for five times to test the same monosilane sample. The test results are shown in Table 1.

[0053] Comparative Example 1

[0054] The same monosilane sample was tested and analyzed as in Application Example 1, except that the system of the present invention was not used. The sample was the same monosilane sample as that used in Application Example 1, and the test was repeated five times. The test results are shown in Table 1. The system in Comparative Example 1 differs from that in Application Example 1 in that the pressure regulating valve 2 and pressure sensor 3 are not provided on the sample gas inlet pipe, and the flow meter 7 and air resistance 8 are not provided on the exhaust gas outlet pipe 18.

[0055] The comparison results are shown in Table 1 below:

[0056] Table 1

[0057]

[0058] By comparing the data before and after using the system of the present invention, it can be seen that after using the system of the present invention, the RSD of the peak area of ​​each impurity detected 5 times under the same conditions is significantly reduced, that is, the repeatability of the sampling detection using the system of the present invention is significantly improved, which helps to improve the detection accuracy.

[0059] It will be readily understood that the above embodiments are merely examples for clarity of description and are not intended to limit the present invention to these embodiments. Persons skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to provide an exhaustive list of all possible implementations. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A sampling and tail gas treatment system for silane gas analysis, comprising a six-way valve and a purge gas inlet pipe, and further comprising a sample gas inlet pipe, a carrier gas inlet pipe, a quantitative loop and an tail gas outlet pipe respectively connected to the six-way valve; characterized in that: The system also includes a tail gas absorption tank; The tail gas output pipe includes an upstream pipe section and a downstream pipe section that are interconnected along the airflow direction, and the purge gas input pipe is connected to the tail gas absorption tank through the downstream pipe section of the tail gas output pipe; The sample gas inlet pipe is provided with a pressure regulating valve and a pressure sensor, and the pressure regulating valve and the pressure sensor are respectively connected to the pressure controller for communication; The carrier gas inlet pipe is provided with a carrier gas pressure reducing valve and a flow controller for adjusting the carrier gas flow rate in the carrier gas inlet pipe; The upstream pipe section of the tail gas output pipe is provided with a flow meter and a one-way valve.

2. The sampling and tail gas treatment system for silane gas analysis according to claim 1, characterized in that: The quantitative ring can be switched between a first communication state and a second communication state by opening and closing the six-way valve; When the quantitative loop is in the first communication state, the inlet of the quantitative loop is connected to the carrier gas inlet pipe, and the outlet of the quantitative loop is connected to the downstream separation and detection system; When the quantitative loop is in the second connected state, the sample gas inlet pipe, the quantitative loop, and the upstream pipe section of the exhaust gas output pipe are connected in sequence, and the carrier gas inlet pipe is connected to the downstream separation and detection system through a connecting pipe.

3. The sampling and tail gas treatment system for silane gas analysis according to claim 1 or 2, characterized in that: The inner cavity of the exhaust gas absorption tank includes an absorption liquid holding area, and a gas diffusion element for diffusing the exhaust gas into the absorption liquid holding area is provided in the absorption liquid holding area. The gas diffusion element is connected to the outlet end of the downstream pipe section of the exhaust gas output pipe through an exhaust gas inlet pipe, and an anti-backflow ball is provided on the exhaust gas inlet pipe.

4. The sampling and tail gas treatment system for silane gas analysis according to claim 3, characterized in that: The gas diffusion element is provided with a gas inlet and an exhaust gas collecting chamber. The gas inlet is communicated with the exhaust gas inlet pipe and the exhaust gas collecting chamber respectively. The exhaust gas collecting chamber has a plurality of gas outlet holes.

5. The sampling and tail gas treatment system for silane gas analysis according to claim 4, characterized in that: The multiple air outlet holes of the exhaust gas collecting chamber are distributed around the circumference and bottom of the exhaust gas collecting chamber.

6. The sampling and tail gas treatment system for silane gas analysis according to claim 4, characterized in that: The diameter of the gas inlet on the gas inlet side is larger than the diameter of the gas outlet side; The tail gas collecting chamber has an inner diameter that is narrow at first and then wide along the gas flow direction.

7. The sampling and tail gas treatment system for silane gas analysis according to claim 6, characterized in that: An air resistance is provided between the flow meter and the one-way valve.

8. The sampling and tail gas treatment system for silane gas analysis according to claim 3, characterized in that: A sample gas pressure reducing valve is provided on the sample gas inlet pipe.

9. The sampling and tail gas treatment system for silane gas analysis according to claim 3, characterized in that: The inner cavity of the tail gas absorption tank is provided with a drain port, the drain port is connected to a drain pipeline, and a drain valve is provided on the drain pipeline.

10. The sampling and tail gas treatment system for silane gas analysis according to claim 3, characterized in that: A purge valve is provided on the purge gas input pipe.

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