A gas inlet compression device for plasma etching experiment under low pressure environment

Abstract

The utility model relates to plasma processing technical field especially relates to a kind of for low-pressure environment under plasma etching experiment gas inlet compression device. In low-pressure plasma etching, process gas is diffuse after decompression, and the existing gas inlet device is low in collection efficiency, and airflow direction is disorderly, leading to poor etching uniformity. The utility model includes compression cavity and the honeycomb structure in the compression cavity gas inlet end inside;The honeycomb structure is formed by multiple polygonal channels in array arrangement, and each channel extends along the compression cavity central axis, to guide low-pressure diffuse gas molecules;Compression cavity is parabolic gradually tapered structure along airflow direction, to focus and compress gas. The device also includes gas outlet pipe in the compression cavity gas outlet, and flow sensor and regulating valve are provided on the gas outlet pipe, and constant gas supply flow is maintained by closed-loop control. The utility model effectively improves the gas collection efficiency and compression ratio, and guarantees the uniformity and repeatability of etching experiment.

Description

Technical Field

[0001] This utility model relates to the field of plasma processing technology, and in particular to an air intake compression device for plasma etching experiments under low pressure. Background Technology

[0002] In plasma etching experiments, the process gas is typically depressurized from a high-pressure cylinder to the Pascal level (0.1 Pa to 10 Pa) via a pressure reducing valve before being introduced into the reaction chamber for discharge etching. However, the gas expands rapidly after passing through the pressure reducing valve, exhibiting a molecular flow or transition flow state within the pipeline, resulting in extremely strong dispersion and randomness.

[0003] Existing experimental air intake devices mostly adopt simple straight-through or tapered tube structures, which mainly have the following problems:

[0004] (1) Low collection efficiency: Low-pressure diffused gas escapes or accumulates in the dead corner of the pipe before entering the compression chamber. The proportion of gas that actually enters the discharge zone is insufficient. The gas collection efficiency of traditional smooth straight pipe structure is usually less than 40%, which leads to a lower discharge zone density under the same gas flow rate and the etching rate does not reach the expected level.

[0005] (2) Turbulent airflow direction: Under low pressure, gas molecules are mainly in random thermal motion, and their direction is chaotic. After entering the discharge area, the spatial distribution is uneven, which directly causes the anisotropic deviation of the etching pattern and the increase of sidewall roughness, resulting in the distortion of experimental data.

[0006] (3) Poor discharge stability: When the gas supply fluctuation causes a small change in the gas pressure in the discharge zone, it will change the plasma sheath voltage and ion bombardment energy, resulting in poor repeatability of the results of the same set of experiments, which seriously affects the reliability of the experimental conclusions. Utility Model Content

[0007] This invention addresses the shortcomings of existing technologies by developing an air intake compression device for plasma etching experiments under low-pressure environments. It improves gas collection efficiency and compression ratio by using a honeycomb structure to guide low-pressure diffused gas, a parabolic compression chamber to focus and compress the airflow, and a closed-loop control system with a flow sensor and regulating valve to maintain a constant gas supply. This effectively enhances the uniformity and repeatability of the etching experiment.

[0008] The technical solution to the technical problem solved by this utility model is as follows: This invention provides an air intake compression device for plasma etching experiments under low pressure, comprising a compression chamber and a honeycomb structure. One end of the compression chamber is an air inlet, and the other end is an air outlet. The compression chamber has a parabolic tapering structure along the airflow direction. The honeycomb structure is disposed inside the air inlet end of the compression chamber. The honeycomb structure is composed of multiple polygonal channels arranged in an array, with adjacent polygonal channels sharing sidewalls to form a honeycomb grid. The polygonal channels extend along the central axial direction of the compression chamber.

[0009] By adopting the above technical solution, the honeycomb-structured polygonal channel guides the gas molecules in the low-pressure diffused state, so that the gas molecules that originally moved in random directions obtain a velocity component consistent with the central axis of the compression chamber, thereby effectively introducing a large number of gas molecules that would otherwise escape into the compression chamber; the parabolic tapered structure compression chamber further focuses and compresses the gas, and the synergistic effect of the two significantly improves the gas collection efficiency, while eliminating the flow separation and eddy current loss caused by abrupt changes in the flow channel, making the airflow direction more consistent and the flow velocity smooth, effectively improving the uniformity of gas spatial distribution in the discharge area.

[0010] As an improvement to the above solution, this utility model also includes an exhaust pipe and a controller. The exhaust pipe is externally connected to the exhaust port of the compression chamber. A flow sensor and a regulating valve are provided on the exhaust pipe. The flow sensor and the regulating valve are electrically connected to the controller.

[0011] By adopting the above technical solution, the flow sensor monitors the gas flow rate in the outlet pipe in real time, the regulating valve adjusts its opening according to the monitoring signal of the flow sensor, and the controller receives the signal from the flow sensor and controls the regulating valve to act. The three work together to achieve real-time stable regulation of the gas supply flow rate, which can effectively suppress minor flow disturbances caused by gas cylinder pressure drop, pressure reducing valve drift or pipeline temperature change, ensure constant gas flow rate entering the discharge zone, maintain stable gas pressure in the discharge zone, thereby ensuring the consistency of discharge conditions between multiple etching experiments and improving the repeatability of experimental data.

[0012] As an improvement to the above scheme, the polygonal channel is a regular hexagonal channel.

[0013] By adopting the above technical solution, the regular hexagonal channel has a regular shape and is closely arranged, which increases the probability of gas molecules colliding with the wall and improves the guiding efficiency.

[0014] As an improvement to the above scheme, the flow sensor is located upstream of the regulating valve along the gas flow direction.

[0015] By adopting the above technical solution, the flow sensor is set upstream of the regulating valve, which can detect flow changes before the regulating valve. The controller can drive the regulating valve to respond before the flow fluctuations affect the downstream, thereby achieving advanced regulation and improving the response speed and gas supply stability of the closed-loop control loop.

[0016] As an improvement to the above solution, the air outlet pipe is integrally formed with the air outlet of the compression chamber.

[0017] By adopting the above technical solution, the integral molding eliminates the connection gap between the compression chamber and the outlet pipe, avoiding gas vortex or leakage at the joint under low pressure environment, and ensuring airtightness and smooth transition of the airflow channel.

[0018] As an improvement to the above solution, the honeycomb structure is embedded inside the air inlet end of the compression chamber, the outer contour of the honeycomb structure is adapted to the inner wall of the air inlet end of the compression chamber, and the outer peripheral wall of the honeycomb structure is fixedly connected to the inner wall of the compression chamber.

[0019] Compared with existing technologies, the above solution has the following advantages or beneficial effects: 1. In the honeycomb structure, multiple parallel polygonal channels increase the probability of gas molecules colliding with the walls, allowing gas molecules that originally moved in random directions to acquire a velocity component consistent with the channel direction, thus effectively guiding them into the compression chamber. The measured gas collection efficiency reaches over 70%, far exceeding the less than 40% level of traditional smooth straight-through pipe structures, solving the problem of difficult collection of low-pressure diffused gas.

[0020] 2. After the honeycomb-structured parallel channels initially guide the gas molecules, the parabolic compression cavity further eliminates flow separation and eddy current losses caused by abrupt changes in the flow channel, achieving a measured compression ratio of approximately 100 times. With the gas flow entering the discharge region in a highly consistent direction, the uniformity of the gas spatial distribution in the discharge region is significantly improved, directly contributing to the enhancement of the verticality of the etching profile and the consistency of the etching rate.

[0021] 3. The closed-loop control of the flow sensor and regulating valve effectively suppresses minor flow disturbances caused by cylinder pressure drops, pressure reducing valve drift, or pipeline temperature changes. Stable gas supply ensures highly consistent discharge conditions across multiple etching experiments, fundamentally guaranteeing the repeatability of experimental data and the reliability of comparative analysis. Attached Figure Description

[0022] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0023] Figure 1This is a schematic diagram of the air intake compression device used for plasma etching experiments in a low-pressure environment according to this embodiment.

[0024] Figure 2 This is a right view of the air intake compression device used for plasma etching experiments in a low-pressure environment according to this embodiment.

[0025] Figure 3 This is a cross-sectional structural diagram of the air intake compression device used for plasma etching experiments under low pressure in this embodiment.

[0026] In the diagram, 10 is the compression chamber; 20 is the exhaust pipe; 30 is the honeycomb structure; and 31 is the regular hexagonal channel. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] In the description of this utility model, it should be understood that the terms "length", "width", "height", "upper", "lower", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] In this utility model, unless otherwise explicitly specified and limited, the terms "setting," "installing," "connecting," and "connecting" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0030] Example See Figure 1-3 This embodiment provides an air intake compression device for plasma etching experiments under low pressure, including a compression chamber 10 and an air outlet pipe 20. One end of the compression chamber 10 is an air inlet, and the other end is an air outlet. The air outlet pipe 20 is externally connected to the air outlet of the compression chamber 10.

[0031] The air inlet of the compression chamber 10 is a circular opening. A honeycomb structure 30 is embedded in the inner end of the compression chamber 10 near the air inlet, and the outer peripheral wall of the honeycomb structure 30 is fixedly connected to the inner wall of the compression chamber 10. To achieve this fixed connection, methods including, but not limited to, interference fit, vacuum brazing, and vacuum inorganic adhesive bonding can be used. In this embodiment, an interference fit is preferred, pressing the honeycomb structure 30 into the end of the compression chamber 10, ensuring its outer peripheral wall is tightly fitted and fixed to the inner wall of the compression chamber 10.

[0032] The honeycomb structure 30 is composed of multiple polygonal channels arranged in an array, with adjacent polygonal channels sharing sidewalls to form a honeycomb grid. The polygonal channels extend along the central axial direction of the compression chamber 10, meaning the extension direction of the polygonal channels is parallel to the central axis of the compression chamber 10. The polygonal channels located in the central region of the honeycomb structure 30 are open at both ends, allowing gas molecules to flow in from the inlet end of the polygonal channel, be guided by the polygonal channel, and then flow out from the other end into the interior of the compression chamber 10. The polygonal channels located in the edge region of the honeycomb structure 30 serve as support structures, with their tails blocked by the parabolic inner wall of the compression chamber 10, and do not participate in the ventilation.

[0033] Preferably, the polygonal channel is a regular hexagonal channel 31, the distance between opposite sides of the hexagons forming the honeycomb grid is 8 mm, the wall thickness of adjacent honeycomb walls is 1 mm, and the length of the honeycomb structure 30 is 40 mm. When the process gas molecules in the low-pressure (0.1~10 Pa) dispersed state move to the air inlet of the compression chamber 10, the gas molecules enter the regular hexagonal channel 31 of the honeycomb structure 30. The wall surface of the regular hexagonal channel 31 increases the probability of collision between the gas molecules and the wall surface, so that the gas molecules that originally move in a random direction obtain a velocity component consistent with the direction of the regular hexagonal channel 31 (i.e., the central axis of the compression chamber 10), thereby effectively guiding the dispersed gas molecules into the compression chamber 10.

[0034] The compression chamber 10 adopts a parabolic design, with a gradually narrowing structure along the airflow direction, and its inner wall generatrix is ​​a continuous and smooth parabolic shape. In this embodiment, the axial length of the compression chamber 10 is 100mm, the inlet diameter is 100mm, the outlet diameter is 20mm, and the vertex of the parabola is located at the central axis of the outlet pipe 20 downstream of the outlet. The central axis of the compression chamber 10 is parallel to the extension direction of the regular hexagonal channel 31 of the honeycomb structure 30, so that gas molecules guided by the honeycomb structure 30 enter the interior of the compression chamber 10 in a direction parallel to the central axis of the compression chamber 10.

[0035] When gas molecules guided by the honeycomb structure 30 enter the compression chamber 10, they are reflected on the parabolic inner wall. Due to the geometric characteristics of the parabolic wall, the gas molecules, after being reflected by the wall, further maintain a velocity component consistent with the central axis of the compression chamber 10. The flow direction of the airflow tends to be smooth and focused, eliminating the flow separation and eddy current losses caused by abrupt changes in the flow channel in traditional straight-through or tapered pipe structures.

[0036] The outlet of the compression chamber 10 is integrally formed with an outlet pipe 20, which has a diameter of 20mm. This integral forming eliminates the connection gap between the compression chamber 10 and the outlet pipe 20, preventing gas eddies or leaks at the joint under low pressure, and ensuring airtightness and a smooth transition of the airflow channel. The outlet pipe 20 is used to output the compressed high-density gas to the plasma discharge zone. A flow sensor and a regulating valve are installed on the outlet pipe 20. The flow sensor monitors the gas flow rate through the outlet pipe 20 in real time, and the regulating valve adjusts the opening of the outlet pipe 20 according to the monitoring signal from the flow sensor.

[0037] The flow sensor and regulating valve are connected to an external controller via signal lines, forming a closed-loop control circuit. When a slight fluctuation in the gas supply flow occurs due to a drop in cylinder pressure, pressure reducing valve drift, or changes in pipeline temperature, the flow sensor detects the flow change in real time and transmits the signal to the controller. The controller, based on the deviation between the preset flow value and the actual detected value, sends a control command to the regulating valve. The regulating valve adjusts its opening accordingly, restoring the actual flow to the preset value. Through this closed-loop control, fluctuations in the gas supply flow are suppressed in real time, ensuring a constant gas flow into the discharge zone. This maintains stable gas pressure in the discharge zone, improves the stability of the electron mean free path, and significantly enhances the gas ionization rate.

[0038] Preferably, the flow sensor is located upstream of the regulating valve along the gas flow direction. The flow sensor can detect flow changes before the regulating valve, and the controller can drive the regulating valve to respond before the flow fluctuations affect the downstream, thereby achieving proactive regulation and improving the response speed and gas supply stability of the closed-loop control loop.

[0039] It should be noted that the signal transmission and closed-loop control principles between the flow sensor, regulating valve, and controller described above are all prior art known in the field, and this utility model does not involve any improvement to the control method or control algorithm itself. The improvement of this utility model lies in the specific structural positions and connection relationships of the flow sensor and regulating valve on the outlet pipe 20. Through the improved layout of the hardware structure and combined with the closed-loop control principles of existing technology, stable regulation of the air supply flow is achieved.

[0040] In this embodiment, the gas inlet compression device is installed at the front end of the gas supply pipeline of the plasma etching equipment, located between the pressure reducing valve and the reaction chamber. The process gas, after being depressurized to the Pascal level (0.1–10 Pa) by the pressure reducing valve from a high-pressure gas cylinder, enters the inlet of the compression chamber 10 in a dispersed state. The honeycomb structure 30 guides the dispersed gas molecules. Within the hexagonal channel 31, the gas molecules collide with the wall surface, acquiring a velocity component aligned with the central axis of the compression chamber 10, thus guiding a large number of gas molecules that would otherwise escape into the compression chamber 10. After entering the compression chamber 10, the parabolic inner wall further maintains the axial velocity component of the gas molecules, focusing and compressing the airflow to form a high-density airflow with a consistent direction and smooth flow rate. The compressed high-density gas enters the outlet pipe 20 through the outlet of the compression chamber 10, and is then output to the plasma discharge zone through the outlet pipe 20. A flow sensor and regulating valve maintain a constant flow rate in real time, ensuring stable gas pressure in the discharge zone and guaranteeing the uniformity and repeatability of the etching experiment.

[0041] Through simulation and ultra-low orbit wind tunnel testing, the air intake compression device using the above-described specific embodiment achieves a gas collection efficiency of over 70% and a compression ratio of approximately 100 times under a low pressure environment of 0.1–10 Pa. This means the gas number density at the outlet is approximately 100 times that at the inlet. The airflow direction consistency at the outlet of the exhaust pipe 20 is significantly better than that of the traditional straight-through pipe structure, and the uniformity of gas spatial distribution in the discharge area is significantly improved.

[0042] Although the specific embodiments of the utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the utility model. Based on the technical solution of the utility model, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the utility model.

Claims

1. An air intake compression device for plasma etching experiments under low pressure, characterized in that, include: Compression chamber (10), one end of the compression chamber (10) is an air inlet and the other end is an air outlet, the compression chamber (10) has a parabolic tapering structure along the airflow direction; A honeycomb structure (30) is provided inside the air inlet end of the compression chamber (10). The honeycomb structure (30) is composed of multiple polygonal channels arranged in an array. Adjacent polygonal channels share sidewalls to form a honeycomb grid. The polygonal channels extend along the central axial direction of the compression chamber (10).

2. The air intake compression device for plasma etching experiments under low pressure environment according to claim 1, characterized in that, The air outlet of the compression chamber (10) is connected to an air outlet pipe (20).

3. The air intake compression device for plasma etching experiments under low pressure environment according to claim 2, characterized in that, The outlet pipe (20) is equipped with a flow sensor and a regulating valve.

4. The air intake compression device for plasma etching experiments under low pressure environment according to claim 3, characterized in that, Along the gas flow direction, the flow sensor is located upstream of the regulating valve.

5. The air intake compression device for plasma etching experiments under low pressure environment according to claim 3, characterized in that, It also includes a controller, and the flow sensor and the regulating valve are electrically connected to the controller.

6. The air intake compression device for plasma etching experiments under low pressure environment according to claim 1, characterized in that, The polygonal channel is a regular hexagonal channel (31).

7. The air intake compression device for plasma etching experiments under low pressure environment according to claim 2, characterized in that, The air outlet pipe (20) and the air outlet of the compression chamber (10) are integrally formed.

8. The air intake compression device for plasma etching experiments under low pressure environment according to claim 1, characterized in that, The honeycomb structure (30) is embedded inside the air inlet end of the compression chamber (10). The outer contour of the honeycomb structure (30) is adapted to the inner wall of the air inlet end of the compression chamber (10), and the outer peripheral wall of the honeycomb structure (30) is fixedly connected to the inner wall of the compression chamber (10).

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