CN114588738B - Double-loop RF capacitively coupled discharge plasma-enhanced getter device - Google Patents

Abstract

The invention relates to a double-ring radio frequency capacitive coupling discharge plasma enhanced getter device, wherein a hollow cylinder with holes in a wall surface is arranged in a vacuum cavity, the upper end of the hollow cylinder with holes in the wall surface is sealed, the lower end of the hollow cylinder with holes in the wall surface is opened, the outer wall of the hollow cylinder with holes in the wall surface is hermetically connected with the bottom end of the vacuum cavity, an electric heating element is arranged in the hollow cylinder with holes in the wall surface, the lower end of the electric heating element extends out of the vacuum cavity from the lower end opening of the hollow cylinder with holes in the wall surface and is connected with an external power supply, two annular single-group parallel electrodes are arranged outside the vacuum cavity, a radio frequency power supply system is arranged on one side of the vacuum cavity, the two single-group parallel electrodes are both connected with the radio frequency power supply system, a vacuumizing system is arranged on one side of the bottom end of the vacuum cavity, and an air pressure acquisition system is arranged on the other side of the bottom end of the vacuum cavity. The invention effectively makes up the defect of long activation time of the large-volume getter in simple heating through a heating and radio frequency electromagnetic field coupling mode, and the plasma generated by radio frequency discharge can improve and strengthen the getter suction rate.

Description

Double-loop RF capacitively coupled discharge plasma-enhanced getter device

technical field

The invention relates to the technical field of vacuum adsorption, in particular to a double-ring radio frequency capacitive coupling discharge plasma enhanced getter device.

Background technique

At present, industrial applications and basic scientific research in many fields need to be carried out in a vacuum environment, such as coating, heat treatment, micro-electromechanical system, surface science, atomic physics, nanotechnology and semiconductor industry. For vacuum technology, the internal vacuum environment and vacuum degree directly affect the working range and efficiency, especially after entering the 21st century, with the continuous improvement of various application indicators and the deepening of basic discipline research, its operation and research The environment requires different degrees of high vacuum or even ultra-high vacuum to maintain, which also puts forward higher requirements and challenges for the process of vacuum packaging process and the means of obtaining the subsequent vacuum environment. Therefore, in addition to using conventional vacuum acquisition methods, such as In addition to mechanical pumps, molecular pumps, cryopumps and other technologies, vacuum adsorption technology based on getter materials has gradually attracted attention and has shown a more important role.

Non-evaporable getter (Non-Evaporable Getter, NEG) has been used in scientific research and industrial production of electric vacuum devices, ultra-high vacuum acquisition, atomic energy industry, etc. because of its low equilibrium pressure, large suction capacity and high suction rate. got applied. Generally speaking, at present, this type of getter material needs to be heated when it is working, and then the getter can have the function of getter, and this process is called the activation process of the getter. The traditional process of activating the getter is generally heated by a heating wire or a heating rod, and the getter is activated at high temperature and begins to absorb gas.

However, although NEG has unique advantages in the application of high vacuum and ultra-high vacuum devices and has been widely used, with the acceleration of industrialization in the new century in my country, the limitations of this type of suction method are gradually reflected: ①Industrialization Devices are no longer limited to small vacuum devices (such as chemical laser adsorption systems), and often need to be enlarged. For large devices to obtain high vacuum, it is still necessary to use getters for adsorption treatment on the basis of conventional acquisition methods. In this case, it is often necessary to increase the amount of getter, that is, a large volume of getter may be required to achieve the high vacuum effect of a large device. How to ensure the encapsulation and air absorption of large-volume getters is a technical problem; ②When the getter is activated by heating, its electrothermal conversion efficiency is relatively low, and it usually takes a period of time before the getter can be activated And then to absorb gas to achieve the purpose of obtaining a higher vacuum, especially for the large-volume getter material used in the enlarged industrial device, it may take longer to activate, which leads to not only the energy required for a long time Stable and continuous injection, and it is less suitable for flexible and quick activation of inhalation; ③ The getter is selective for the adsorption of some gases, and the inhalation rate will be greatly affected depending on the type of gas. At the same time, the temperature and time of getter activation are also accompanied by considerable differences. For some gases that are difficult to absorb, such as nitrogen, it often requires a high temperature of several hundred degrees Celsius to activate the getter, and the inspiratory rate after activation How to effectively increase the adsorption rate of quantitative getters for gases that are difficult to adsorb is very important.

The existence of the above problems sometimes limits the comprehensive application functions of getters. It is very important to find a device that can meet the current application requirements of large-volume getters and improve the activation time and adsorption rate.

Contents of the invention

The purpose of the present invention is to provide a double-loop RF capacitively coupled discharge plasma-enhanced getter device, which can effectively make up for the shortcoming of the long activation time of the large-volume getter in the simple heating method through heating and RF electromagnetic field coupling, and The plasma generated by radio frequency discharge can increase the number of active particles correspondingly, and improve the disadvantage of the getter's slow inhalation rate for some difficult-to-adsorb gases, thereby further accelerating the inhalation rate of the system.

The purpose of the present invention is achieved by the following technical solutions:

A double-ring radio frequency capacitively coupled discharge plasma-enhanced getter device, including a gas supply system, a diffuser, and a vacuum chamber connected in sequence, wherein a hollow cylinder with holes on the wall is arranged in the vacuum chamber, and the The upper end of the hollow cylinder with holes on the wall is sealed, the lower end is open, and the outer wall is sealed and connected to the bottom of the vacuum chamber. The hollow cylinder with holes on the wall is provided with an electric heating element, and the lower end of the electric heating element is controlled by the hollow cylinder with holes on the wall. The opening at the lower end protrudes out of the vacuum chamber to connect with an external power supply. There are two ring-shaped single-group parallel electrodes on the outside of the vacuum chamber. A radio frequency power supply system is provided on one side of the vacuum chamber, and the two single-group parallel electrodes are connected to the The radio frequency power supply system is connected, and a vacuum pumping system is provided on one side of the bottom end of the vacuum cavity, and an air pressure collection system is provided on the other side.

The bottom end of the vacuum chamber is provided with a bottom sealing flange upper cover and a bottom sealing flange lower cover stacked together, and the lower end of the hollow cylinder with holes on the wall passes through the bottom sealing flange After the cover is fixedly connected with the lower cover of the bottom sealing flange, the lower cover of the bottom sealing flange is grounded, and the lower cover of the bottom sealing flange is provided with a power supply heating element inserted into the hollow cylinder with holes on the corresponding wall through interface.

The upper end of the hollow cylinder with holes on the wall is provided with a detachable threaded cover.

The top of the vacuum cavity is provided with a top sealing flange, and the lower end of the diffuser is provided with a diffuser lower flange and the top sealing flange.

The diffuser is a hollow metal cylinder with a thin upper end and a thicker lower end.

The gas supply system includes a gas supply source, a mass flow meter and a diffuser connector, the gas supply source and the diffuser connector are connected through a gas delivery pipeline, and the mass flow rate is set on the gas delivery pipeline. A flowmeter, the lower end of the diffuser connector is provided with a connector flange, the upper end of the diffuser is provided with a diffuser upper flange, and the connector flange is fixed to the diffuser upper flange. Connect even.

The diffuser connector is a hollow metal cylinder with a thin upper end and a thicker lower end.

The vacuum pumping system includes a vacuum pump and a control valve, the vacuum pump is connected to the corresponding interface of the vacuum chamber through a connecting pipeline, and the connecting pipeline is provided with the control valve; Vacuum gauge, vacuum gauge display, digital information acquisition card and computer.

The single group of parallel electrodes is a group of metal rings, and the metal rings are strip metal plates, the radio frequency power supply system includes a series of radio frequency power supplies and matchers in series, and the matchers pass through different same The shaft transmission line is connected to two single sets of parallel electrodes, and one of the single set of parallel electrodes is connected to the ground.

The vacuum system first extracts the gas in the vacuum chamber, and then the getter in the hollow cylinder with holes on the wall is activated by heating with the electric heating element, and then the radio frequency power supply system is activated to make the output power act on the vacuum chamber through two single sets of parallel electrodes , and generate plasma in the vacuum chamber.

Advantage of the present invention and positive effect are:

1. The present invention enables the output power of the radio frequency power supply system to act on the vacuum cavity through a single set of parallel electrodes, and generates a radio frequency electric field between two single sets of parallel electrodes and forms a capacitive coupling discharge, so that plasma can be generated inside the vacuum cavity Therefore, the shortcoming of the large-volume getter in the simple heating method and the long activation time can be effectively compensated by means of heating and radio frequency electromagnetic field coupling.

2. The plasma generated by the radio frequency discharge in the present invention can increase the number of active particles correspondingly, improve the disadvantage of the getter's slow inhalation rate for some difficult-to-adsorb gases, and further accelerate the inhalation rate of the system.

3. The present invention can fully meet the application requirements of some large-scale devices requiring large-volume getters.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

Among them, 1-vacuum cavity; 2-bottom sealing flange upper cover; 3-bottom sealing flange lower cover; 4-top sealing flange; 5-electric heating element; 6-diffuser lower flange; 7-diffuser; 8-diffuser upper flange; 9-connector flange; 10-diffuser connector; 11-mass flowmeter; 12-air supply source; 13-control valve; 14- Vacuum pump; 15-vacuum gauge; 16-vacuum gauge display; 17-digital information acquisition card; 18-computer; 19-hollow cylinder with holes on the wall; 20-threaded cover; 21-radio frequency power supply; 22-matching device; 23 - coaxial transmission line; 24 - single set of parallel electrodes; 25 - ground wire; 26 - radio frequency power supply system; 27 - air pressure collection system; 28 - vacuum pumping system; 29 - gas supply system.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

As shown in Figure 1 , the present invention includes a gas supply system 29, a diffuser 7 and a vacuum chamber 1 connected in sequence, wherein a hollow cylinder 19 with holes in the wall is provided in the vacuum chamber 1, and a hollow cylinder 19 with holes in the wall is provided. The upper end of the cylinder 19 is sealed, the lower end is open, and the outer wall is sealed and connected to the bottom end of the vacuum chamber 1. An electric heating element 5 is arranged in the hollow cylinder 19 with holes on the wall, and the lower end of the electric heating element 5 is hollowed out by a hole in the wall surface. The lower end opening of the cylinder 19 protrudes to the outside of the vacuum chamber 1 to connect with an external power source. There are two ring-shaped single sets of parallel electrodes 24 on the outside of the vacuum chamber 1, and a radio frequency power supply system 26 is provided on one side of the vacuum chamber 1. And the two single groups of parallel electrodes 24 are both connected to the radio frequency power supply system 26 , a vacuum pumping system 28 is provided on one side of the bottom of the vacuum chamber 1 , and an air pressure collection system 27 is provided on the other side.

As shown in Figure 1, the bottom end of the vacuum chamber 1 is provided with a bottom sealing flange upper cover 2 and a bottom sealing flange lower cover 3 which are stacked together and fixedly connected by bolts, and the bottom sealing flange A sealing element is provided between the flange upper cover 2 and the bottom sealing flange lower cover 3, and the bottom sealing flange lower cover 3 is grounded, and the hollow cylinder 19 with holes on the wall is a hollow cylinder made of metal material. cylinder, the lower end of which passes through the bottom sealing flange upper cover 2 and is welded together with the bottom sealing flange lower cover 3, and a straight-through interface is provided on the bottom sealing flange lower cover 3, and The center of the rear opening of the hollow cylinder 19 with holes on the wall coincides with the center line of the corresponding straight-through interface on the lower cover 3 of the bottom sealing flange, and the electric heating element 5 can be inserted into the vacuum chamber through the adapter through the through-hole body 1 and sealed, the front end of the hollow cylinder 19 with holes on the wall is provided with a detachable threaded cover 20 to achieve sealing, and the screwed cover 20 can be opened to add and contain getter materials Placement and replacement, the outer diameter and length of the hollow cylinder 19 with holes on the wall are smaller than the vacuum chamber 1, and it needs to be placed inside the vacuum chamber 1 as a whole during work.

In this embodiment, the shape of the vacuum cavity 1 is a hollow cylinder, and it is made of a sealable and high-temperature-resistant insulating material, such as quartz or ceramics. The electric heating element 5 is an electric heating rod, and the sealing element It can be an oxygen-free copper sealing ring, graphite sealing ring, O-ring, sealant, etc., and the adapter can be a flange, KF joint, stainless steel straight joint, PTFE straight joint, etc.

As shown in Figure 1, the top of the vacuum chamber 1 is provided with a top sealing flange 4, and the lower end of the diffuser 7 is provided with a diffuser lower flange 6 and the top sealing flange 4 is fixedly connected by bolts, Therefore, the diffuser 7 and the vacuum cavity 1 are connected as a whole, and the diffuser 7 is a hollow metal cylinder with a thin upper end and a thicker lower end.

As shown in Figure 1, the gas supply system 29 includes a gas supply source 12, a mass flow meter 11 and a diffuser connector 10, and the gas supply source 12 is connected to the diffuser connector 10 through a gas delivery pipeline , and the mass flow meter 11 is provided on the air supply pipeline, the connector flange 9 is provided at the lower end of the diffuser connector 10, and the diffuser upper flange 8 is provided at the upper end of the diffuser 7, Moreover, the connector flange 9 and the diffuser upper flange 8 are fixedly connected by bolts, and the diffuser connector 10 is also a hollow metal cylinder with a thin upper end and a thicker lower end. The air supply pipeline can be metal hard pipes such as stainless steel and iron, or high temperature and high pressure insulating pipes such as polytetrafluoroethylene and Teflon. The mass flow meter 11 can control the steady air pressure in the vacuum chamber at a constant airflow speed. The gas supply source 12, the gas supply pipeline, the diffuser connector 10 and the diffuser 7 are serially connected in series, and the diffuser 7 is sealed with the vacuum chamber 1, so that the vacuum chamber can be adjusted by changing the gas supply source 12 1, the type and pressure of the gas can be controlled by the mass flow meter 11, the diffuser 7, etc. and the flow rate of the gas. The mass flow meter 11 is a well-known technology in the art and is a commercially available product.

As shown in Figure 1, the vacuum pumping system 28 includes a vacuum pump 14 and a control valve 13, the vacuum pump 14 is connected to the corresponding interface on the vacuum cavity 1 through a connecting pipeline, and the connecting pipeline is provided with the The control valve 13 is described. The vacuum pump 14 is turned on for pumping the gas in the vacuum chamber 1 to obtain a vacuum, and its initial vacuum degree and pumping rate are controllable by the control valve 13 . In this embodiment, the control valve 13 is a needle valve, which is a well-known technology in the art and is a commercially available product.

As shown in FIG. 1 , the air pressure acquisition system 27 includes a vacuum gauge 15 , a vacuum gauge display 16 , a digital information acquisition card 17 and a computer 18 connected in series. The vacuum gauge 15 is connected to the corresponding interface on the vacuum chamber 1 through a pipeline, and it is used to monitor the pressure and its variation in the vacuum chamber 1, and its indication can be read from the vacuum gauge display 16, and the vacuum gauge display 16 The pressure change displayed on the upper surface can be collected by the software on the computer 18 through the digital information acquisition card 17, and the pressure change inside the vacuum chamber 1 can be measured effectively and rapidly. The vacuum gauge 15, the vacuum gauge display 16, the digital information acquisition card 17 and the computer 18 are all technologies known in the art.

The single group of parallel electrodes 24 is a group of metal rings, the material of which can be copper, iron, nickel, stainless steel and other metals, and the metal rings are mainly formed by winding strip metal plates

As shown in Figure 1, the radio frequency power supply system 26 includes a radio frequency power supply 21, a matcher 22 and a coaxial transmission line 23, wherein the radio frequency power supply 21 can output a radio frequency signal of 50-10000 watts after passing through the matcher 22, and acts on a single group Working on parallel electrodes 24. Two single-group parallel electrodes 24 are arranged outside the vacuum chamber 1, and the high-voltage output ends of the matcher 22 are respectively connected to the two single-group parallel electrodes 24 through different coaxial transmission lines 23, and one of the single-group parallel electrodes 24 Connected to the ground wire 25, when the output power of the RF power supply 21 acts on a single set of parallel electrodes 24, a radio frequency electric field is generated between the two single sets of parallel electrodes 24 and a capacitive coupling discharge is formed, so that plasma can be generated inside the vacuum cavity 1 role. The radio frequency power supply 21, the matcher 22, and the coaxial transmission line 23 are all well-known technologies in the art and are commercially available products.

Working principle of the present invention is:

When the present invention is working, the gas in the vacuum cavity 1 is first extracted by the vacuum system 28 to obtain a lower air pressure environment when the getter works, and the working air pressure can be properly adjusted within a certain range through the air supply system 29 and the diffuser 7 , gas type and flow rate, and then the electric heating element 5 is energized to heat and activate the getter in the hollow cylinder 19 with holes on the wall surface, and the radio frequency power supply system 26 is started to make the output power act on the vacuum cavity through a single set of parallel electrodes 24 1, a radio frequency electric field is generated between two single sets of parallel electrodes 24 to form a capacitive coupling discharge, so as to achieve the effect of generating plasma inside the vacuum cavity 1 . The invention improves the activation time of the getter by means of the electric heating and the coupling energy of the radio frequency power supply system, and at the same time, the gas-sucking rate of the getter in the whole device can be accelerated through the active species generated in the plasma.

Claims (8)

1. A kind of dicyclo radio frequency capacitive coupling discharges the plasma strenghthened type getter device, characterized by that: the vacuum heating device comprises an air supply system (29), a diffuser (7) and a vacuum cavity (1) which are sequentially connected, wherein a wall surface hollow cylinder (19) is arranged in the vacuum cavity (1), the upper end of the wall surface hollow cylinder (19) is sealed, the lower end of the wall surface hollow cylinder (19) is opened, the outer wall of the wall surface hollow cylinder is hermetically connected with the bottom end of the vacuum cavity (1), an electric heating element (5) is arranged in the wall surface hollow cylinder (19), the lower end of the electric heating element (5) extends out of the vacuum cavity (1) from the lower end opening of the wall surface hollow cylinder (19) and is connected with an external power supply, two annular single-group parallel electrodes (24) are arranged on the outer side of the vacuum cavity (1), a radio frequency power supply system (26) is arranged on one side of the vacuum cavity (1), the two single-group parallel electrodes (24) are both connected with the radio frequency power supply system (26), a vacuumizing system (28) is arranged on one side of the bottom end of the vacuum cavity (1), and an air pressure acquisition system (27) is arranged on the other side of the vacuum cavity (1);

the single group of parallel electrodes (24) are a group of metal rings, the metal rings are strip-shaped metal plates, the radio frequency power supply system (26) comprises a radio frequency power supply (21) and a matcher (22) which are sequentially connected in series, the matcher (22) is respectively connected with the two single group of parallel electrodes (24) through different coaxial transmission lines (23), and one single group of parallel electrodes (24) is connected with a ground wire (25);

the vacuum pumping system (28) firstly pumps gas in the vacuum cavity (1), then a getter in the hollow cylinder (19) with holes on the wall surface is heated and activated by the electric heating element (5), and then the radio frequency power supply system (26) is started to enable output power to act in the vacuum cavity (1) through the two single-group parallel electrodes (24) and enable plasma to be generated in the vacuum cavity (1).

2. The dual ring radio frequency capacitively coupled discharge plasma enhanced getter device of claim 1, wherein: the vacuum cavity is characterized in that a bottom end sealing flange upper cover (2) and a bottom end sealing flange lower cover (3) which are overlapped together are arranged at the bottom end of the vacuum cavity (1), the lower end of the hollow cylinder (19) with the wall surface holes penetrates through the bottom end sealing flange upper cover (2) and then is fixedly connected with the bottom end sealing flange lower cover (3), the bottom end sealing flange lower cover (3) is grounded, and a through connector for inserting a power supply heating element (5) into the hollow cylinder (19) with the wall surface holes is arranged on the bottom end sealing flange lower cover (3).

3. The dual-ring rf capacitively coupled discharge plasma enhanced getter device according to claim 2, wherein: the upper end of the hollow cylinder (19) with the hole on the wall surface is provided with a detachable screw thread sealing cover (20).

4. The dual ring radio frequency capacitively coupled discharge plasma enhanced getter device of claim 1, wherein: the vacuum cavity (1) top is equipped with top sealing flange (4), diffuser (7) lower extreme be equipped with diffuser lower flange (6) with top sealing flange (4) are connected.

5. The dual ring radio frequency capacitively coupled discharge plasma enhanced getter device of claim 4, wherein: the diffuser (7) is a hollow metal cylinder with a thin upper end and a thick lower end.

6. The dual-ring rf capacitively coupled discharge plasma enhanced getter device according to claim 1, wherein: air supply system (29) is including air feed air supply source (12), mass flow meter (11) and diffuser connector (10), air feed air supply source (12) is connected through the pipeline of supplying air with diffuser connector (10), just be equipped with on the pipeline of supplying air mass flow meter (11), diffuser connector (10) lower extreme is equipped with connector flange (9), diffuser (7) upper end is equipped with diffuser upper flange (8), just connector flange (9) with diffuser upper flange (8) link firmly.

7. The dual ring radio frequency capacitively coupled discharge plasma enhanced getter device of claim 6, wherein: the diffuser connector (10) is a hollow metal cylinder with a thin upper end and a thick lower end.

8. The dual ring radio frequency capacitively coupled discharge plasma enhanced getter device of claim 1, wherein: the vacuum pumping system (28) comprises a vacuum pump (14) and a control valve (13), the vacuum pump (14) is connected with a corresponding interface on the vacuum cavity (1) through a connecting pipeline, and the control valve (13) is arranged on the connecting pipeline; the air pressure acquisition system (27) comprises a vacuum gauge (15), a vacuum gauge display (16), a digital information acquisition card (17) and a computer (18) which are sequentially connected in series.

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