GT2004 microwave plasma experiment device
Instruction manual (with experimental notes)
First, the plasma (Plasma) overview
1. Definition of plasma:
Plasma is a collection of electrons, ions, atoms, molecules or radicals generated by dissociation or ionization of gas molecules by a certain means (such as heating, direct current, radio frequency, laser, microwave, etc.). Whether the gas is partially ionized or fully ionized, the total number of positive charges and the total number of negative charges in the plasma are always equal in value, so it is called plasma.
2. Plasma characteristics:
a) Conductivity
b) the interaction with the magnetic field
c) Standard quasi-neutral
d) It has strong activity, many metastable atoms are excited, and the chemical reaction is easy to carry out. It is a new process with promising future and wide application.
3. Plasma classification:
= 1 \* ROMAN I) Particle energy classification: a) high temperature plasma b) low temperature plasma
= 2 \* ROMAN II) Classification of particle density: a) dense plasma (or high pressure plasma) b) thin plasma (or low pressure plasma)
= 3 \* ROMAN III) Classification of ways to generate plasma: a) combustion plasma b) arc plasma c) high-frequency plasma d) microwave plasma e) laser plasma, etc.
4. Plasma application:
Plasma display, plasma TV, plasma lightning protection technology, plasma stealth technology, plasma sterilization technology, plasma spray technology, plasma cutting technology, plasma chemical vapor deposition technology, plasma light source
5. Application of plasma in chemistry and chemical industry:
Catalyst preparation and catalytic reaction, plasma biomass conversion technology, plasma water treatment technology, plasma waste treatment technology, plasma food preservation technology, plasma greenhouse gas research, plasma synthesis technology
Second, the introduction of plasma technology
Plasma technology is a new technology with global influence. In recent years, it has entered the field of industrial application with great momentum. In addition to it has been widely used in welding, cutting, spraying, nitriding, metallurgy, chemical industry, etc. It has penetrated into many high-tech fields such as microelectronics, optoelectronics, optical recording, magnetic recording, flat panel display, magnetic fluid power generation, surface treatment of materials, preparation of thin films and ultra-fine ultra-pure micro-powder, as a kind of green (no environmental pollution) Industrial technology, high-tech industrialization and traditional production for the world
The transformation has direct and significant impact.
In plasma application technology, microwave plasma has the advantages of low energy consumption, high efficiency, low cost, no electrode and large area, and is especially suitable for the preparation of new materials (including thin films and bulk materials), surface modification of metal products, Surface modification of high polymer products and films, fabrication of very large scale integrated circuits and high power electronic devices and optoelectronic devices, development of nanostructured materials and devices and mechanical products, development of new illumination sources and ultraviolet light sources, etc. Is the development frontier of current plasma application technology.
At present, microwave plasma is widely used in the following aspects:
1 Microwave plasma chemical vapor deposition to prepare various functional film materials, such as BN film, diamond film, etc. c-BN film has ultra-high hardness, high thermal conductivity and good chemical thermal stability, and is widely used in machinery, electronics and other fields. Application. Since microwave plasma adopts electrodeless discharge, plasma has the advantage of low impurity concentration, and is particularly suitable for preparing optical diamond film;
2 The surface of the material is modified by microwave plasma, such as the modification of natural silk fabric and wool by microwave plasma, thereby improving the printing property of natural silk and wool; modifying the surface of the polymer material to change the physical properties of the material. Chemical properties, improve the hydrophilicity, cohesiveness, electroplating and bio-matching of materials. Microwave plasma has high purity, high density, no attached products, no environmental pollution, and has unique advantages in surface modification of materials;
3 Microwave plasma cleaning of the surface of the material, its specific applications include:
(1) Surface activation of plastics, glass and ceramics. Glass, ceramics and plastics (eg polypropylene, PTFE, etc.) are essentially non-polar, so these materials are surface activated prior to bonding, painting and coating. .
(2) Metal degreasing and cleaning. Metal surfaces often have organic substances such as grease and oil, and oxide layers. They are used before sputtering, painting, bonding, bonding, welding, brazing, and PVD and CVD coating. Plasma treatment to obtain a completely clean and oxide-free surface. Before soldering: Usually printed circuit boards are treated with chemical flux before soldering. These chemicals must be removed by plasma after soldering, otherwise corrosion will occur. Problem. In addition, good bonding is often weakened by plating, bonding, and residue during soldering. These residues can be selectively removed by plasma. At the same time, the oxide layer is also harmful to the quality of bonding. Plasma is also required. clean.
4 Microwave plasma chemical synthesis. For example, ammonia and hydrogen are used to synthesize ammonia under microwave plasma conditions; methane and hydrogen are used to synthesize carbon nanotubes under microwave plasma; and methane and nitrogen are used to synthesize CN nanotubes under microwave plasma conditions. .
Third, the instrument introduction and scope of use
The device uses a microwave with a frequency of 2.45 GHz to excite a rare gas discharge, and a microwave with a frequency of 2.45 GHz generated by a microwave source is transmitted in a TE10 mode along a BJ22 rectangular waveguide to prevent the reflected wave from being burnt out due to improper load matching. Tube, the circulator and the water load are connected to the microwave transmission line, the short-circuited piston is adjusted, and finally the gas is excited in the water-cooled cavity reaction chamber to form an axisymmetric plasma ball. The diameter of the plasma ball depends on the gas pressure in the vacuum deposition chamber. And microwave power. Under normal conditions, Φ50mm plasma is generated in the quartz tube. The microwave plasma generated by the device has many advantages: no internal electrode, can avoid discharge pollution, wide operating pressure range, high energy conversion efficiency, and can generate a wide range High density plasma.
The substrate table is located at the center of the reaction chamber of the quartz tube. The heating of the substrate is completed by self-heating of the plasma. The device can provide two kinds of substrate structure according to the use: one is with cooling water, which is suitable for lower The substrate temperature is required; the other substrate is not water-cooled, the substrate temperature is adjusted by the contact of the substrate with the plasma, and is measured by a thermocouple. The substrate table can be flexibly adjusted up and down, double The layer water-cooled bracket and the substrate table can be easily disassembled and maintained. Even if the samples appear in different forms (sheet, block, powder, etc.), it is very convenient to replace or modify the substrate table.
The quartz tube is equipped with water cooling protection to ensure safe and stable operation of the vacuum chamber under high power and long working conditions.
The vacuum system of this equipment adopts 2XZ-2 rotary vane vacuum pump, the ultimate vacuum is 6×10-1 Pa, the pumping speed is 2 l/s, the rated speed is 1400 rpm, and the solenoid valve and high are set between the mechanical pump and the vacuum chamber. The vacuum diaphragm valve is additionally provided with a bypass line controlled by a high vacuum trimmer valve to facilitate the safe operation of the vacuum system and flexible control of the reaction gas pressure during operation. The vacuum seal is sealed with metal and rubber, usually: metal copper is used for the relatively fixed interface. Sealed, rubber seal with relative movable interface.
The background vacuum measurement of the system uses a pointer-type resistance vacuum gauge, and the working pressure in the reaction chamber is measured by a digital thermal resistance vacuum gauge.
Plasma technology has two main characteristics in industrial applications:
1. Plasma has higher temperature and energy density than chemical methods; plasma can generate a large number of active particles or groups, resulting in physical and chemical reactions that are impossible or difficult to achieve in conventional chemical reactions.
2. Plasma technology is characterized by high efficiency, energy saving and environmental protection compared with other industrial processing methods that can compete with it. Therefore, in the preparation of functional materials, plasma etching, chemical synthesis, surface modification of materials, etc. Has an irreplaceable wide range of applications.
At present, high-temperature plasma controlled nuclear fusion research has made remarkable achievements in the world. The research on high-temperature magnetic confinement plasma of the Institute of Plasma Physics of the Chinese Academy of Sciences was rated as China's top ten science and technology news in 2003, while the plasma industry Technology is also being used more and more widely in many high-tech fields. In modern integrated circuit processing, 80% of the technology uses plasma. Therefore, plasma physics and plasma engineering technology are in modern scientific research and industrial technology. The importance of this is gradually being accepted. In recent years, the basic knowledge about plasma has been written into the physics textbook of science and engineering. In many science and engineering departments, such as material synthesis and application, chemical synthesis, modern processing technology, environmental protection, etc. In the textbooks, the application of plasma in these fields can be seen everywhere. However, because the price of plasma devices is generally expensive, universities and colleges rarely experiment with plasma physics and plasma technology, and students have no chance to carry out this. Aspect training. Multi-functional microwave plasma device is specially designed by our factory to solve this problem. The integrated products designed by the research institutes for colleges and universities and research institutions can be used for professional experiments of students majoring in physics, materials and chemistry, as well as for ordinary physics experiments of engineering students, as well as for plasma physics and Research in plasma technology applications, such as the synthesis of functional thin film materials, planar optical waveguide materials, semiconductor thin film materials, preparation and processing of microelectronic devices, synthesis of nanomaterials, surface modification of materials, plasma chemistry and many other aspects. The device has the advantages of compact structure, high cost performance, flexible operation and the like. With this device, a series of experiments on industrial applications of plasma technology can be provided for students, and it can also be used as a suitable tool for students to understand the principle of plasma.
Fourth, the instrument structure diagram and description
1, the chassis shell 2, resistance vacuum gauge
3. Thermal resistance vacuum gauge 4. Rotor flowmeter (gas path = 1 \* ROMAN I)
5, rotameter (gas path = 2 \ * ROMAN II) 6, high vacuum trim valve
7. Vacuum corrugated pipeline 8. Intake air source pipeline
9, intake air source = 1 \ * ROMAN I interface 10, intake air source = 2 \ * ROMAN II interface
11, diaphragm valve 12, thermal resistance vacuum gauge power switch
13, the resistance vacuum gauge power supply open 14, the observation window on the reaction chamber
15. Short-circuit piston adjustment knob 16. Vacuum reaction chamber
17, microwave transmission system bracket 18, guide pulley
19, adjustable fixed machine feet 20, the total power indicator
21, anode voltmeter 22, anode current meter
23, reflection measurement micro-ampere table 24, microwave power adjustment
25, the main power switch 26, cooling water power switch
27, vacuum pump power switch 28, high voltage power switch
29, magnetron shell 30, magnetron
31, water load (matching BJ22 detector) 32, circulator
33, three screw impedance adapter 34, substrate temperature switch
35, cooling water temperature controller 36, substrate temperature display
37, front door handle
Figure 1, the whole machine structure
Instrument configuration instructions:
2. Resistance vacuum gauge: used to measure the background vacuum in the reaction chamber. When the vacuum pump draws the background vacuum, the background vacuum in the reaction chamber is measured, and the system is closed when working.
The measurement range is: 1.0×105 ～1.0×10-1 Pa, measurement accuracy: ≤3%
3. Thermal resistance vacuum gauge: used to measure the working pressure in the reaction chamber when the system is working. The input signal standard thermal resistance, measurement range: 0 ~ 100KPa, measurement accuracy: 0.2% FS
4. Rotor flowmeter (gas path = 1 \* ROMAN I): used to control the flow rate of external gas source, control range: 6-60ml/min
5, rotameter (gas path = 2 \ * ROMAN II): used to control the flow of external gas source, control range: 25-250ml / min
20. Anode voltmeter: used to measure and display the magnitude of the anode voltage of the magnetron. The actual voltage value during measurement is the indication value on the voltmeter × 1000 volts. It is the actual voltage output value.
21, anode current meter: used to measure the current of the magnetron anode when working, by adjusting the magnitude of the anode current can change the power of the microwave source.
22, reflection measurement micro-ampere meter: used to qualitatively measure the size of the microwave reflected back from the cavity.
29. Magnetron: used to generate microwaves with a frequency of 2.45 GHz.
30, water load (matching a BJ22 detector): used to absorb reflected microwaves. In order to prevent the reflected wave from burning out, the magnetron is filled with flowing water in the water load, so that the reflected microwave is water
Absorption, water is a good conductor to absorb microwaves.
31. Circulator: To prevent the reflected wave from being damaged due to improper load matching, the magnetron is burned out.
32. Three-screw impedance adapter: Adjust the three-screw impedance adapter during operation to minimize the deflection of the pointer of the micro-ampere meter, minimize the reflection of the microwave, and obtain the largest micro-in the reaction chamber.
Wave power source. The energy of the plasma is concentrated.
Fifth, the main configuration and composition of the instrument
The GT2004 multi-functional microwave plasma experimental device consists of microwave source, vacuum system, gas supply system, cooling water system, microwave transmission and microwave cavity.
1. Microwave power source: 800W microwave power source generates microwave with frequency of 2.45GHz through magnetron. Microwave power is controlled by adjusting anode voltage. The anode voltage adjustment range is from 0 to 4000 volts. It is simple, reliable and easy to maintain. The circuit realizes continuous adjustable output of microwave power.
Magnetron: It adopts the general-purpose magnetron in the industry. The magnetron has the characteristics of long service life and high reliability, and it is easy to maintain.
2. Vacuum system: The 2XZ-2 rotary vane vacuum pump is used to extract the gas from the sealed container to obtain the vacuum. The vacuum measurement is combined with the digital display piezoresistive vacuum gauge thermocouple vacuum gauge for measuring the background vacuum and working. Working pressure at the time. The vacuum seal is sealed with metal and rubber; the vacuum adjustment is finely adjusted by the diaphragm valve coarse adjustment and fine adjustment valve, and the adjustment is quick and convenient, and the stability is good.
2XZ-2 rotary vane vacuum pump main technical indicators:
1) Working voltage: AC220V/50 Hz 2) Pumping rate: 2L/S 3) Limit pressure: 6×10-1 Pa 4) Motor power: 0.37KW
5) Inner diameter of inlet: 25mm 6) Oil consumption: 0.65L 7) Noise: 72LwdB(A)
See the working principle and instructions for use (Appendix 2)
Figure 2, vacuum system, gas supply system schematic
1) Vacuum pump 2) Exhaust gas hose
3) Vacuum suction hose 4) Reaction chamber vacuum bellows
5) Reaction chamber air source intake pipe 6) Solenoid valve
7) Diaphragm valve 8) Trim valve
9) Flowmeter = 1 \* ROMAN I 10) Flowmeter = 2 \* ROMAN II
Figure 3, schematic diagram of the cooling water system
1) condenser 2) shut-off valve 3) booster pump
4) Water outlet 5) Water return port 6) Compression pump
7) Stainless steel water tank 8) Water level display 9) Water injection port
Each injection volume can be observed from the water level display. Each injection volume is about 20 kg. Please clean the water tank at regular intervals. There is a water discharge valve at the bottom of the stainless steel water tank. When the water tank is cleaned, the valve is opened and the external connection is made. The water pipe can drain the water in the water tank.
3. Gas supply system: There are two independent gas supply channels, which can control the flow through the rotor flowmeter.
4. Cooling water system: The device is equipped with circulating cooling water. The cooling water of the whole system is circulated by its own water tank and water pump. The water temperature control in the cooling water circulation system is controlled by MTC-2000 temperature controller (see Appendix 3 for specific operation instructions). ), refrigeration is cooled by a refrigerator compression pump to ensure normal operation of the system
Requirements for water temperature. There are no special requirements for the water source in the laboratory.
5. Microwave transmission and microwave cavity system: The microwave power propagates forward along the rectangular waveguide in TE10 mode. After passing through the circulator and the three-screw impedance adapter, it is transferred to the microwave cavity by adjusting the short-circuit piston to concentrate the microwave energy into the reaction cavity. Thereby exciting the gas discharge to generate plasma. The microwave transmission profile is shown in the following figure:
Figure 4, microwave transmission system diagram
1) short circuit piston 2) microwave cavity
3) Three screw impedance adapter 4) Circulator
5) Magnetron 6) Water load
Sixth, technical parameters and characteristics
1, working voltage
AC220V±5% 50Hz
4, the weight of the whole machine
125Kg
7, the reaction chamber limit pressure
6×10-1 Pa
2, the whole machine power
3000W
5, the size (cm)
Length 65 × width 55 × height 165
8, the reaction chamber size
Φ50mm
3, microwave power
0～800W
6, the reaction chamber working pressure
Hundreds of kPa to ten kPa
9, substrate temperature control
200～1000°C
Seven, equipment installation and commissioning
1. Installation environment requirements
1) Power supply: AC220V, 50Hz, maximum power 3000W
2) Temperature, humidity, gas source and cooling water: the equipment should be kept stable and normal.
3) Installation room: clean indoors, air circulation, no dust.
4) Grounding wire: indoor with independent grounding wire <3Ω
2, the installation sequence
1) Confirm that the installation environment meets the equipment installation requirements
2) Check the equipment for good condition (check if damage is caused during transportation)
3) Check the lifting double-layer water-cooled bracket to confirm that the quartz tube, the substrate table and the transmission parts are intact.
4) Install the microwave transmission system body bracket.
5) Install the microwave transmission system according to Figure 2, connect the high-voltage power supply line of the magnetron, and the filament power supply line. Note: Connect the working ground wire of the magnetron. Install the outer casing of the magnetron.
Confirm that the electrical components are intact.
6) Connect the vacuum corrugated pipe and the vacuum corrugated pipe, and install the reaction chamber sample stage.
7) Connect the equipment ground wire.
8) Turn off the flowmeter and connect the two air sources.
Eight, equipment operation and precautions
1) Check that all parts of the equipment are in good condition and the connection is safe (pay attention to grounding).
2) Turn on the main power supply, turn on the main power switch button, confirm the water capacity of the cooling water tank and the MTC-2000 water cooling control system (please refer to the MTC-2000 operating instructions for details)
After the setting is completed, turn on the cooling water switch button.
3) Open the diaphragm valve, confirm that the air line connection specification is intact, open the vacuum pump switch button, and pump the reaction chamber background vacuum.
4) Turn on the thermal resistance vacuum gauge power switch and measure the pressure of the reaction chamber at this time.
5) Open the resistance vacuum gauge power switch, vacuum for about 5 minutes to make the background vacuum meet the required requirements. Measure the background vacuum of the reaction chamber, the vacuum is better than 20Pa.
6) Turn on the flowmeter switch, send the working air source to the vacuum chamber, and turn off the working power of the resistance vacuum gauge.
7) Turn on the high-voltage switch button, adjust the microwave power adjustment knob, load the anode current to about 150mA, generate the microwave with the frequency of 2.45GHz, and reverse the water-cooled cavity.
The indoor excitation gas should form a plasma ball, close the diaphragm valve, and adjust the trim valve to achieve the required working pressure.
8) Adjust the short-circuit piston and the height of the working platform to make the device work stably.
9) At the end of the test, adjust the anode current to 0, turn off the high pressure switch button, close the gas circuit, turn off the vacuum pump, turn off the cooling water, and turn off the main power.
Nine, equipment maintenance
1. Regularly replace the cooling water and clean the cooling water tank to ensure the normal operation of the circulating water system.
2. When the quartz tube wall is contaminated, open the vacuum reaction chamber in time to clean the quartz tube wall (to avoid scratching the inner wall of the quartz tube with sharp objects).
3. All electrical knobs and switch states must be confirmed in the "original" state before use.
4. Vacuum system maintenance:
1) Pay attention to the vacuum pump to change the oil;
2) Pay attention to the cleaning of the reaction chamber and pipeline;
3) Pay attention to the cleaning of the sealing surface;
4) Turn off the vacuum gauge power before stopping the vacuum system, and then perform other operations.
5) Empty the vacuum chamber after the end of the experiment.
Ten, common faults and solutions
1. After the microwave power is applied, the discharge does not occur and there is no plasma.
Possible cause: the diaphragm valve is not open, the air pressure in the reaction chamber is too high, the plasma is difficult to excite; or the vacuum in the reaction chamber is too high; it may also be the position of the reflector
The three screws do not match.
Solution: Open the diaphragm valve completely, or adjust the position of the reflector, the height of the three screws. If the vacuum of the reaction chamber is too high, the working gas can be passed.
2. Under normal working pressure, the plasma ball is not above the substrate stage, but against the quartz tube wall.
Possible cause: The position of the reflector is not suitable and needs to be adjusted.
3. The vacuum gauge indication is not normal.
Possible cause: The output line on the regulator or sensor is detached or loose, and the oil in the regulator or sensor is contaminated.
Treatment: Check the wiring, such as oil, remove the regulation or sensor, carefully wash with ethanol solution, and air dry.
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