KR20210145715A - Microwave System - Google Patents

Abstract

Disclosed is a microwave system comprising: a high-frequency semiconductor module that oscillates microwaves; an AC-DC conversion inverter that converts input AC power to DC and supplies power to the semiconductor module; an automatic control board that adjusts and supplies power and reduces or cuts the power when reflected waves are generated; an applicator wherein power is supplied and a plunger is installed to minimize the reflected wave power to transmit the microwaves; a power supply device provided with a gateway to exchange signals with the outside, and connected to the applicator and connector, a coaxial cable, and a coaxial conversion adapter to transmit the microwaves; and an isolator embedded in the power supply device, and diffracting the reflected wave to protect the high-frequency semiconductor module. Therefore, the present invention is capable of having an effect of remarkably improving work efficiency.

Description

Microwave System

The present invention relates to a microwave system, and more particularly, to a high-frequency semiconductor that generates microwaves, a transmission line that is an accessory thereof, an adapter such as a co-axial transition device, a matching algorithm through frequency modulation, and a circuit protection system It relates to a microwave system comprising a.

In general, microwave is a type of electromagnetic wave, and the frequency (f) bandwidth is from 300 MHz to 30 GHz (wavelength standard: 1 cm - 1 m). 1 MHz < f (frequency) < 300 MHz is called Radio Frequency. f (frequency) < 1 MHz is called low frequency. In general, microwaves (ultra-high frequency, Microwave) and radio waves (Radio-Frequency) are separated and named according to frequency bands as described above. For frequency bands of hundreds of MHz, such as 300 MHz), and in the present invention, it is generally referred to as microwave or high frequency. When a microwave or high frequency is generated using a semiconductor device, it is called Solid State Microwave (SSMW) or Solid State Radio-Frequency (SSRF).

Microwaves have the property of being completely reflected when they touch the metal. However, when a non-metal dielectric is irradiated with microwaves, it penetrates into the dielectric, rotates and vibrates polar molecules in the molecule, and generates heat by internal friction. This heat causes the microwave irradiated object to be heated. A typical example of using this closely in real life is the microwave oven.

Devices using microwaves are next-generation industrial technologies that can dramatically reduce working time, process costs, energy, and labor costs. The industrial application fields of microwaves are very wide, and the applications in the food field include heating, drying, thawing, sterilization, and cooking. In particular, when microwave energy is irradiated to food, it can penetrate the surface of the food and heat the inside very quickly, so that it has a minimal effect on the taste, smell, texture, and nutritional value of the food. As for other industrial applications, existing industries include rubber processing, paper fabric dyeing, fixing and drying, and wood drying, while new business groups include military use, semiconductor and display production, electronic product production process, and medical use. have.

Microwaves can also be used in the field of medical devices. High-frequency diathermy (high-frequency diathermy, 高周波療法) is a type of medical device that uses microwaves and is used to heat deep tissues. It is a type of electrotherapy using high-frequency radio waves, and the most frequently used among them is microwave (electromagnetic wave with a wavelength of 1m to 1cm) therapy. As an effect obtained by this, the thermal effect on deep tissue is mentioned. Diseases to which it can be adapted include inflammation of the musculoskeletal system, lateral sclerosis, shoulder syndrome, bruises, etc. When high-frequency electromagnetic radiation passes through, it is a method of heating the tissue by the resistance of the body tissue. In medical diathermy, the tissue is warmed but not destroyed. On the other hand, in electrocoagulation [surgical diathermy] tissue is destroyed.

One of the most widely used fields other than heating and drying of microwave energy is the field of plasma generation. Plasma is the fourth state of matter (The Fourth State of Matter), which means a state in which electrons, ions, neutrons, protons, etc. are mixed. In a microwave (ultra-high frequency) or high-frequency plasma generator, electrons selectively obtain energy and become a high-level energy state, collide with a source gas (neutron), and more electrons, anions, cations, various atoms, and molecules dissociated from proto-molecules Species, neutrons synthesized between various molecules and atoms, and active radicals in which each neutron is activated are generated. Depending on which species is used in the plasma state, they are called chemically reactive plasma, ion beam plasma, electron beam plasma, and reactive ion plasma. Since these activated radicals can cause reactions that are possible at high temperatures to occur even at low temperatures, they are being applied in numerous industrial fields such as semiconductor and display manufacturing, combustion, lighting, and chemical industries. In addition, the largest field among the fields related to the plasma generation field is the lighting field. In the case of plasma discharge lamps, unlike other existing lighting sources such as incandescent lamps, fluorescent lamps, and metal halide, it is electrodeless, the brightest light source, has a long lifespan, is continuous white light, and can generate light with an intensity of 140 lm/W. There are advantages. In the case of such a semiconductor device plasma light source, it is a light source having a continuous spectrum of almost 400 to 800 nm wavelength, and is a natural light source almost similar to sunlight, environmentally friendly and has a long lifespan. Since other existing light sources use electrodes, energy efficiency is low and their lifespan is short due to contamination and corrosion, whereas plasma light sources have a long lifespan because they are electrodeless. For example, about 70% of the source light comes out and the time it takes to reach it is about 50,000 hours in the case of a plasma light source of a semiconductor device, but only 20,000 hours in the case of an existing high intensity discharge lamp. Another advantage is that it is the most efficient light source emitting almost 130-140 lm of light flux per 1W of output. The conventional plasma light source generates plasma by receiving energy from a special inverter (electronic ballast for electrodeless lamps) capable of oscillation at low frequency (250KHz band), and the electrons in the plasma react with the gas enclosed in the lamp to generate ultraviolet rays This UV light passes through the three-wavelength fluorescent material applied to the inside of the lamp and is finally emitted as visible light to become a long-life, high-efficiency lighting source. Table 1 shows the comparison of advantages and disadvantages of various other existing lighting sources and AC semiconductor device (low frequency/high frequency) plasma lighting sources.

Lighting Types light source
type life span
(hrs) magnitude
(klm) energy efficiency
(lm/W) chromaticity
Rendering color temperature
(K) light on
hour
(Sec) light up again
hour
(Sec) Incand-
scented incandescent lamp 2,000 1,700 10-17 100 3,200 0.1 0.1 Fluore-
scented Fluorescent lamp 10,500 3,000 115 51-76 2,940 ~
6,430 0.3 0.1 LED LED 25,000 130 60~
100 30 6,000 0.1 0.1 High intensity discharge (HID) high brightness
discharge lamp 20,000 25,000 65~
115 40-94 4,000 ~
5,400 60 480 AC (LF/RF) Plasma AC (Low Frequency/RF)
plasma 50,000 25,000 100~
140 70-94 4,000 ~
5,500 30 25

Table 1 shows the comparison between microwave (ultra-high frequency) and RF (high frequency) plasma illumination sources and conventional illumination sources and shows the superiority of plasma illumination sources. As described above, the names are divided according to frequency bands, but in certain parts, there are cases where these frequencies have similar bands (for example, hundreds of MHz frequency bands such as 300 MHz), so in the present invention, the names are generalized to very high frequency semiconductors. do. The overall configuration of the conventional microwave application device includes a magnetron, a waveguide, a circulator, a dummy load, a 3-stub-tuner, an applicator; an applicator), and a plunger ( Plunger) [this is also called a sliding short circuit] and the power supply power (Power). Each component of the conventional microwave application device is exemplified in Fig. 1. The core generator of the conventional microwave is a magnetron, which is basically similar to a dipole vacuum tube and has a structure in which hot electrons are emitted from the hot wire of the cathode. A high-voltage electric field is applied to the cylindrical outer anode and inner cathode of pure copper, and a magnetic field perpendicular to the electric field is formed by the permanent magnets installed above and below. The electrons protruding from the cathode go to the anode under the influence of the electric field and rotate inside the cylinder under the influence of the magnetic field. The electrons pass through the vanes formed on the anode side and form a high-frequency electromagnetic field in the cavity resonator.

When the electric current flows through the magnetron by changing the AC voltage of 220V to a high voltage of 4000V or higher in the power supply, a microwave that vibrates at a high frequency of 2.45GHz is created in the magnetron. When the microwave hits the object to be irradiated, the dipole constituting the object rapidly changes the direction of its axis arrangement by the high-frequency electric field, and heat is generated by frictional heat at this time. Therefore, only the insulator (dielectric) is heated because radio waves need to penetrate into the object.

When power is supplied to the filament and anode of the magnetron from the power supply, the microwave generated from the magnetron is transmitted to the applicator through the waveguide, the circulator, and the 3-stub-tuner. do. The power absorbed by the irradiated object by the energy of the microwave oscillated from the magnetron is called forward power, and the power that is not absorbed is called reflected power or reverse power. it is called Since the reflected wave power returns and can damage the magnetron, a circulator that changes the direction of the reflected wave is used to protect it, and the energy of the reflected wave is absorbed by the dummy rod through which the coolant flows and is discharged to the outside. Use a 3-stub tuner or plunger as a matcher to minimize reflected waves.

1 shows an example of a plasma generating apparatus using microwaves. As illustrated in FIG. 1, the conventional microwave application device has a configuration in which microwaves generated from a magnetron are matched through a waveguide, a circulator, a 3-stub-tuner and a plunger, and the applicator ( The energy is transmitted to the applicator (applicator).

Other applications are formed with similar structures. If the reflected wave is minimized by calculating the wavelength according to the frequency and adjusting the waveguide length based on this, the 3-stub tuner, isolator (circulator + dummy rod), and plunger can be omitted. A typical example is a microwave oven used at home. In the case of 2.45GHz microwave, magnetrons usually have 1, 2, 3, 6 Kw output methods, and the cooling method uses air cooling for low power and water cooling for high power. When more than 3Kw of energy is required, a plurality of magnetrons are combined and arranged. In the case of 915MHz microwave, 5~100 Kw high-power class magnetron exists, and it is mainly cooled by water cooling.

As illustrated in FIG. 1 , an application device using microwaves is structurally complex, heavy, and bulky. Therefore, there are many difficulties in application fields that require light, thin and compact. Such fields include plasma sources for semiconductor manufacturing, lighting, and medical fields.

As described above, in the case of a conventional microwave application device and process processing, the volume of the microwave application device increases due to the existing magnetron generating microwaves, a circulator, a dummy load, and a matching device for impedance tuning purposes. There has been this difficult and time-consuming problem. Accordingly, an object of the present invention is to facilitate use by removing the heavy and bulky microwave components as described above.

Also, conventionally, since microwaves are oscillated by one magnetron microwave, it has not been easy to achieve a large area and high uniformity. In addition, when a microwave transmission device using a plurality of multiple magnetrons, a power supply device, and a waveguide is used, the above-described bulky and heavy problems are serious, making it difficult to efficiently apply microwaves in various fields. In order to solve these problems, in the present invention, a microwave transmission device using a high-frequency semiconductor module and a waveguide-coaxial cable conversion adapter is made light, thin, and compact, and a microwave system that can be installed efficiently in various ways so that the user can achieve the desired process purpose. is intended to

A microwave system according to the present invention comprises: a high-frequency semiconductor module for oscillating microwaves; AC-DC conversion inverter for supplying power to the semiconductor module by converting the input AC power into DC; An automatic control board that regulates and supplies power and reduces or cuts off power when a reflected wave is generated; An applicator equipped with a plunger to minimize reflected wave power and efficiently transmit microwaves to provide maximum power; a power supply device provided with a gateway for exchanging signals with the outside and connected to the applicator and connector, a coaxial cable and a coaxial conversion adapter to transmit microwaves; and an isolator that is embedded in the power supply device to diffract the reflected wave to protect the high-frequency semiconductor module.

Preferably, the microwave system may further include a control algorithm for minimizing the reflected wave power by modulating a frequency when the reflected wave power is generated within the power supply device.

Preferably, the microwave system may further include a coaxial cable impedance tuner to minimize the reflected wave power when the reflected wave power is generated.

Impedance matching and circuit protection by high-frequency semiconductors that generate microwaves and their accessories, transmission line, waveguide-coaxial conversion adapter [Co-Axial Transition], matching (tuning) algorithm through frequency modulation or coaxial cable impedance tuner In the system, it is possible to form a compact device that is light and has a small volume, and it is possible to simply perform a microwave process, as well as to provide a microwave processing system that can significantly improve work efficiency by easy installation of such a device. have.

In addition, according to the present invention, since a plurality of microwave oscillators can be easily configured and installed, it is possible to increase the area of the microwave device or to install and operate a plurality of simple applications, such as plasma, lighting, medical care, heating, extraction, etc. There is an effect of maximizing the user's efficiency, economy, and convenience for processing each industrial application in the industrial field.

1 is an exemplary configuration diagram for explaining a plasma generator that is a conventional microwave application device.
Figure 2 is an exemplary view showing the components of a plasma generator that is a conventional microwave application device.
3 is a view showing that plasma is generated when each process condition is changed in the conventional plasma generating apparatus using microwaves.
4 is an exemplary view of a microwave oven using a conventional microwave.
5 is a structural diagram of a transmission line (coaxial cable) for microwave transmission.
6 is an exemplary view showing a configuration method in which a magnetron, a circulator, and a dummy load are embedded in a power supply among components of a plasma generator, which is a conventional microwave application device.
7 is an exemplary view showing a configuration method in which a magnetron, a circulator, a dummy rod, and a matching device are embedded in a power supply among components of a plasma generator, which is a conventional microwave application device.
8 is a waveguide-coaxial (cable) conversion adapter (Co-Axial Adapter) and a coaxial cable after embedding a magnetron, a circulator, and a dummy rod among the components of the plasma generating device, which is a microwave application device according to the present invention, in the power supply. An example diagram showing the configuration method to connect to the applicator (application device).
9 shows a magnetron, a circulator, a dummy rod, and a matching device among the components of the plasma generator, which is a microwave application device according to the present invention, embedded in the power supply, and then the waveguide-coaxial (cable) conversion adapter (Co-Axial Adapter) and coaxial Example diagram showing how to connect the cable to the applicator (application device).
10 is an exemplary view showing a microwave application device for generating plasma using a semiconductor microwave oscillator, a transmission line, and a transmission adapter according to the present invention.
11 is an exemplary view showing a microwave application device for generating plasma using a semiconductor microwave oscillation device, a transmission line, and a transmission adapter according to the present invention and a photo of plasma generation.
13 is an exemplary view showing an apparatus configured to enable large-area plasma generation using a plurality of multi-semiconductor microwave power supplies, transmission lines, and transmission adapters according to the present invention;
14 is an exemplary view illustrating a large-area plasma configuration by arranging a plurality of semiconductor microwave generators according to the present invention.
15 is an exemplary diagram illustrating a method of processing by converting the microwave transmitted to the magnetron and the waveguide into a coaxial cable form using a coaxial-waveguide conversion adapter, and then connecting the coaxial rods of each linear plasma antenna as a whole and connecting them in parallel .
16 shows the microwaves transmitted to the magnetron and the waveguide after branching the microwaves using a waveguide splitter, and then converting it to a coaxial cable form using a coaxial-waveguide conversion adapter. An example diagram showing how to connect or subset in parallel and process them.

In order to fully understand the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below.

This embodiment is provided to more completely explain the present invention to those of ordinary skill in the art. Accordingly, the shape of elements in the drawings may be exaggerated to emphasize a clearer description. It should be noted that the same members in each drawing are sometimes shown with the same reference numerals. In addition, detailed descriptions of well-known functions and configurations that are determined to unnecessarily obscure the gist of the present invention will be omitted.

1 is a top view and a side view of a microwave application device. The overall composition of the microwave application device is a magnetron (Magnetron; 111), a waveguide (Waveguie; 112), a circulator (113), a 3-stub-tuner (3stub-tuner; 115), an applicator (Applicator; 117), sliding short It is composed of a circuit 119, a power supply or power 121 that regulates and supplies power to the marnetron. That is, when power is supplied to the filament and the anode of the magnetron (Magnetron; 111), the microwave generated from the magnetron passes through the waveguide, the circulator (113), and the 3-stub-tuner (3 stub-tuner; 115). It is transmitted to the applicator (Applicator, applicator; 117).

A 3-stub tuner is a device with three metal rods in a waveguide or cavity resonator, and is a matching device that maximizes transmission of microwaves without reflection. A plunger or a sliding short circuit (SSC) is also an additionally mounted device for matching in order to minimize reflected waves. Sometimes a 4-stub is used instead of a 3-stub. In addition, either manually adjusting each stub to match (Manual Tuning), or performing automatic tuning by the matching algorithm. The automatic matching machine is composed of a stub, a diode, an integrated automatic control board, and a motor drive unit, and it matches the load impedance by giving o. The matching is described in more detail as follows. In general, when combining two circuits, if the impedance viewed from the output terminal of the first circuit to the input terminal of the same circuit is Z1=R1+jX1, and the input impedance of the second circuit is Z2=R2+jX2, a conjugate between the two impedances (共役) relationship, that is, R1=R2, X1=-X2, the condition of minimum loss and maximum output is obtained. Here, the first circuit is a matching device, and the second circuit is an applicator. That is, the matching is a method for transmitting the maximum output in the signal transmission path. The principle of matching is that the signal source has an internal resistance and for maximum output transmission, the load must be equal to the signal source's impedance. Where active components are included, the input and output impedances are quite different. However, the input impedance needs to be matched to the signal source, and the output load needs to be matched to the output impedance. Power amplifiers and many active components deviate from the basic principles because of the limitations imposed by internal power dissipation and linearity requirements. The output load impedance should be optimally selected with matching impedance to achieve maximum output transmission under these limiting conditions. There are several types of matching methods, such as matching by a conductor rod, matching by a conductor plate window in the waveguide, matching by an anti-reflection termination circuit, matching by a tapered waveguide, and matching by a transformer (/4 impedance converter). have. As illustrated in FIG. 2, in the case of a 3-stub tuner, a conductive rod is inserted into the waveguide from the wide side of the waveguide to match. The plunger matching method is a matching method using the conductor plate window in the waveguide. It is a method of inserting obstacles such as a conductor plate at a right angle to the observation in the waveguide at a distance, and selecting an appropriate distance to the load for matching. 1 and 2 are cases in which the 3-stub tuner matching method and the plunger matching method are mixed.

If the microwave is reflected back from the applicator without being absorbed, the reflected microwave can cause fatal damage to the magnetron. Load; 123), the energy is absorbed. Cooling water is supplied to the dummy rod to dissipate the absorbed heat to the outside. The power that propagates in the propagation direction of the microwave oscillated from the magnetron is called forward power, and the power that is returned without being absorbed by the applicator is reflected power (reflected power). It is called electric power or countercurrent wave power. Since the reflected wave that is not matched and returns the microwave damages the expensive magnetron 111 when transmitted as it is, the direction of the reflected wave is changed separately by the magnet built into the circulator 113, and then the dummy rod 123 ) to be absorbed by the absorbent in the The dummy rod 123 that absorbs heat, the magnetron 111 that generates heat, and the power supply module or power supply 121 are cooled by supplying air or cooling water so that the temperature does not rise, and the reflected wave energy absorbed by the cooling water is emitted to the outside. In order to measure the forward power and the reflected wave power, a directional coupler is sometimes installed between the circulator and the 3-stub tuner. Two microwave-measuring ports are made in the waveguide to measure forward power with the port facing the applicator, and the other is located in the opposite direction, that is, toward the magnetron, and used to measure reflected wave power.

An assembly diagram of a plasma generator using microwaves is illustrated in FIG. 2 . 3 shows pictures of plasma generated using such microwaves. The pictures of plasma generated at each pressure are exemplified by changing the pressure, which is an important process variable.

An exemplary view of a home cooker using microwaves to heat and cook or defrost food is shown in FIG. 4 . In this case, the load impedance was calculated and designed, and the Since it is an application device, the device is simple compared to the plasma application field.

A waveguide, a conduit through which microwaves are transmitted, is an arbitrary structure that propagates by trapping and guiding waves. Mainly, it refers to a hollow conductive metal tube made to propagate electromagnetic waves. The waveguide is applied to high-power, low-loss, millimeter wave systems, and as an example of use, it is used to transmit electromagnetic waves such as radar, satellite repeater, broadcast radio wave transmission or heating, and plasma generation, as described above. is used for The structural form of the waveguide is a metal conductor (copper, brass, aluminum, etc.) that surrounds the electromagnetic waveguide space, and the thickness of the conductor must be sufficiently secured to be about 1-3 mm for mechanical strength. make it double

The frequencies of microwaves allowed by the International Radio Association for industrial, scientific, and medical fields (Industrial, Scientific, Medial: ISM) other than the communication frequencies mainly used for communication are 2.45GHz and 915MHz (0.915GHz). In the case of 2.45GHz microwave, the waveguide dimensions used are WR-284 (internal size: 72.14 x 34.04 mm), WR-340 (internal size: 86.36 x 43.18 mm), WR-430 (internal size: 109.22 x 54.61 mm) is mainly used, and in the case of 915MHz, a WR-975 (internal size: 247.65 x 43.18 mm) waveguide is used. As such, the size of the waveguide is usually determined according to the frequency of the microwave. Waveguides vary from WR-2300 (internal size: 584.2 x 292.1 mm; operating frequency 0.32 to 0.49 GHz) to WR-3 (internal size: 0.86 x 0.43 mm; operating frequency 217 to 333 GHz). The larger the used frequency, the smaller the internal size of the waveguide.

In the microwave oscillator, for transmission of microwave energy, which is an irradiation part, an electric wire cannot be used because it radiates microwaves to the outside, and a metal hollow pipe called a waveguide is usually used. The waveguide is classified into a rectangular or circular waveguide and a ridge-type waveguide having a complex shape depending on the cross-sectional shape. Rectangular waveguides are generally used, and circular and ridge-type waveguides are used for special purposes.

In general, a waveguide that transmits microwaves is in the form of a square tube and transmits microwaves with a spreading characteristic by trapping them in the square tube, and is usually made of brass or copper with good conductivity. Therefore, the square waveguide becomes heavy and large when installing a process or device using microwaves, and assembling becomes difficult. In particular, even in the case of low power, the installation is difficult and application is limited because the device is heavy and heavy. An example of a plasma generator using such a microwave delivery device (see FIGS. 1 and 2 ) is illustrated in FIG. 6 .

For microwave transmission, there is a coaxial cable (coaxial tube) in addition to the waveguide. As the frequency increases, the problem is that the wave easily escapes to the outside. In the case of a frequency of 60Hz or higher, a closed waveguide is used to reduce the wave's escape to the outside. As a closed waveguide method, there are a coaxial cable (Co-Axial Cable), a metal waveguide (Metallic WaveGuide), and a strip line method. A coaxial cable is a system that surrounds the inner conductor with an insulator and shields the outer conductor so that a higher frequency signal can be transmitted than a general power transmission line or wire (a cable made by twisting two twisted wires). It is a form to reduce the wave from escaping out of the cable due to the external conductor.

A coaxial cable is a transmission line with a central conductor supported by polyethylene on the central axis of a pipe made of conductors, and is used to transmit the output signal of the power monitor. Coaxial cable is flammable and easy to handle, but the power tolerance of microwave transmission energy is small. In case of low loss coaxial cable by adjusting impedance of 50ohm, the maximum allowable power of microwave transmission energy is 330 Watt (outer diameter 10mm) to 520Watt (outer diameter 15mm) in the case of frequency 2.45 GHz, and in case of frequency 915 MHz, 330 Watt (outer diameter) 10mm) ~ 520Watts (outer diameter 15mm) and 580 Watts (outer diameter 10mm) ~ 900Watts (outer diameter 15mm). Coaxial cables are used for high-frequency heating devices, but not for microwave heating devices with high power of 300 ~ 500 W or more.

The difference between a transmission line and a waveguide is that a transmission line (including a coaxial line) propagating by TEM mode can also be viewed as a waveguide, but in general, propagation of radio waves by TEM mode is not called a waveguide. In other words, only propagation by TE mode (Transverse Electric Field/Wave) and TM mode (Transverse Magnetic Field/Wave, transverse magnetic field) is mainly used as a waveguide. The shape of the transmission line is composed of two or more conductors, and it is a structure in which the two conductors are isolated by a dielectric. In the energy transfer method, energy is transferred in the form of a reciprocating current/voltage wave flowing through two conductors. When viewed in the form of electromagnetic waves, the radio wave is transmitted as a TEM wave, and is due to the transmission of a current wave or a voltage wave. Because there is no cut-off frequency, it can operate from direct current to very high frequencies, and it is applied to low power and somewhat low frequencies, but it is inefficient in the ultra-high frequency band due to the skin effect and dielectric loss. Coaxial cable is a type of transmission line, and in general, 2-wire parallel cable has a defect in that the effective resistance of the conductor increases at high frequencies due to the skin effect. 5 is the same. Looking at the coaxial cable structure in detail, two cylindrical conductors and dielectrics share a central axis, the inner conductor is used for actual signal transmission, and the outer conductor is a mesh-shaped shield made of aluminum/copper. ) (braided or foil paper), and it is made by filling the gap with dielectric/insulator (polyethylene, etc.) and separating it. At the outermost part, the outer sheath is surrounded by a cable jacket (vinyl, polyethylene, etc.).

The advantage of the coaxial cable is that it is a transmission line with a shielded structure that has little effect on external interference, and since there is no cut-off frequency like a waveguide, it can be used from direct current (DC) to microwaves and millimeter waves. At present, it is possible to reach about 50 or more in short distances. However, in a band of several GHz or more, a loss is large depending on distance, so a waveguide structure is used. The smaller the outer diameter, the higher the frequency can be used, but the power that can be carried is limited, and there is a difficulty in manufacturing. The propagation mode generally operates in the TEM mode. It is used in long-distance telephone network, CATV, video transmission, premises information communication network, etc.

Coaxial cable connectors are BNC, TNC, FT-type, N-type, F-type, and miniature type (SMA, SMB, SMC). Coaxial cable is usually used as a transmission line at frequencies below UHF, but even in microwave circuits above that, silver plating is used for the inner conductor of the steel wire so that the signal flows through the silver plating on the surface of the conductor, resulting in a skin effect in the microwave band. To lower the loss due to the insulator, a material such as Teflon is used as an insulator to lower the dielectric loss.

In the case of using low-power microwaves, there is a method of reducing the volume and weight by using a coaxial cable instead of a waveguide. The plasma generating apparatus using microwaves illustrated in FIG. 6 will be described as an example. If the magnetron (referred to as 'M'), circulator (referred to as 'C'), and dummy rod (referred to as 'D') are outside, they occupy a separate space. It is installed inside the supply device for integration and unification. In this way, considerable spatial reduction is possible, and the power supply to the magnetron is directly connected from the inside and supplied and the cooling line is shared. 3The stub-tuner (matcher or matcher) must be operated manually in case of matching, so place it outside. In the case of the auto tuner, as illustrated in FIG. 7 , the stubs are automatically adjusted to match the impedance. In this case, the tuner can be positioned inside the power supply.

In the case of FIGS. 6 and 7 , it is inconvenient to use a waveguide to connect from the isolator (the sum of the circulator and the dummy rod is referred to as an isolator) to the applicator. In order to solve this part, the present invention discloses a method of converting a microwave waveguide transmission method to a coaxial cable transmission method. That is, if a waveguide-coaxial (cable) conversion adapter that converts the waveguide into a coaxial cable is used, the microwave can be transmitted by finally connecting to the applicator 117 using a coaxial cable instead of the waveguide.

In this case, there is an advantage in that the installation space is additionally reduced and the installation can be facilitated. 8 and 9 respectively show a case where the tuner is outside the power supply (FIG. 6) and when the tuner is inside the power supply (FIG. 7), a case where a waveguide-coaxial cable conversion adapter is installed and used in a simplified manner It is an example diagram. 8 and 9 show an embodiment in which a waveguide-coaxial cable conversion adapter is connected to the waveguide flange of the tuner to convert to a coaxial cable, and the waveguide-coaxial cable conversion adapter is used again to connect to the applicator and use. That is, it is a method to use by connecting the tuner -> waveguide-coaxial cable conversion adapter -> coaxial cable -> coaxial cable-waveguide conversion adapter. The difference between FIGS. 8 and 9 is when the tuner is built into the power supply box (FIG. 9) and when the tuner is external to the power supply box (FIG. 8). As described above, the present invention is characterized in that the microwave device is simplified by using a waveguide-coaxial cable conversion adapter (Co-Axial Adapter) and a coaxial cable. In addition, the present invention includes a method for facilitating installation by embedding the isolator and matching device in the power supply and connecting them with a coaxial cable.

Microwave applications can be greatly simplified if the device is configured using methods such as pre-designing and characterizing the length for accurate impedance matching so that a 3-stub tuner and isolator are not required in the microwave path. have. In addition to these cases, especially in the case of plasma generation, a tuner (matcher) must be used for impedance matching. As a method of not using the conventional tuner 115, there is a method in which the plunger 119 is fused with the applicator 117 as a substitute for the conventional three-stub type tuner (Figs. 1 to 2, 7 to see Fig. 9). The present invention includes a method of using a matching impedance in the form of a plunger.

In addition, instead of using a conventional magnetron and a tuner (matching device), a semiconductor ultra-high frequency generation module is used as a substitute for this conventional method, and the generation frequency is modulated and tuned (FVTM) for use, or a coaxial tuner or plunger is used as an applicator In the case of fusion with and matching impedance, microwave equipment can be used much more simply. The present invention includes an applicator method equipped with such a frequency modulation method (FVTM) or a plunger type matching method. A detailed method for this will be described later.

In order to avoid the conventional method of using a magnetron that oscillates microwaves as in the case of FIGS. 1 to 9, recently, a semiconductor device is used instead of a magnetron to oscillate microwaves, and the semiconductor microwave (Solid-State Micro-) Wave: SSMW) method. The semiconductor used at this time is a silicon-based laterally diffused metal oxide semiconductor [Laterally Diffused-Metal Oxide Semiconducotor LDMOS] Field-Effective Transistor (FET).

Fig. 10 illustrates a plasma generator using a semiconductor microwave power supply. The semiconductor microwave generator is a method of oscillating microwaves using a semiconductor instead of a magnetron used in the past. Since the semiconductor microwave generating module requires the supply of DC power, it includes an AC-DC conversion inverter 225 to convert the AC input power 231 supplied to the power supply 121 into DC, and the inverter is installed on a power control board ( Power is supplied to the Control Board 221 and the semiconductor microwave generating module 223 . In addition, in order to set and control the microwave power to be supplied, the power control board exchanges signals with the outside through a communication gateway (GateWay; 233). There are Analog, Profibus, CanOpen, or Modbus RS232/RS485 methods to communicate with the outside. When the semiconductor microwave module does not properly match during operation, a reflected wave is generated and a cooling line 131 is installed to cool it. In the case of air cooling, installation is relatively simple because only a fan is installed without the need to supply cooling water, and the air supplied from the fan contains heat and is discharged to the outside of the power supply. However, when the reflected wave power is large, it is safe to install a cooling water line because it generates a lot of heat and can be fatal to the microwave semiconductor device.

FIG. 10 exemplifies a method of generating microwaves by the high-frequency semiconductor module embedded up to the cooling water line and delivering them to the applicator. As illustrated in FIG. 10, the microwave generated by the high-frequency semiconductor module is transmitted to the applicator through a connector attached to the power supply end, a coaxial cable, and a coaxial cable-waveguide conversion adapter. It is possible to embed a small isolator 227 inside the microwave power supply 121, and when a reflected wave is generated, the semiconductor microwave generator module 223 is protected through immediate automatic reduction and interruption of the supplied power. Although the cooling line of the isolator is not illustrated in FIG. 10 , the cooling line 131 supplied to the semiconductor microwave generator module 223 may be shared or separately installed and used. 11 illustrates plasma generation by a single linear antenna using a semiconductor microwave generator. Microwave is generated from the semiconductor microwave generating power supply 121 and connected to a linear plasma antenna through a connector (coaxial) -> coaxial cable -> connector (coaxial) and transmitted. 11 shows that the energy of microwaves is transmitted to generate plasma.

11 illustrates plasma generation by a single linear antenna using a semiconductor microwave generator. Microwaves are generated from the semiconductor microwave generation power supply 121 and connected to a linear plasma antenna through a connector (coaxial) -> coaxial cable -> connector (coaxial) and transmitted. FIG. 11 shows that the energy of microwaves is transferred by this method to generate plasma. As illustrated in FIG. 11, when using the semiconductor ultra-high frequency generation module and the frequency modulation tuning method, compared to the conventional method of using a microwave generated from a magnetron by connecting an isolator, a tuner, etc. by connecting a waveguide flange, the application device It can be seen that it is much lighter, thinner and smaller and easier to install.

A microwave generator using such a semiconductor device has the following advantages. (1) 1 ~ Maximum allowable output (For example, the maximum allowable power is about 300 ~ 500Watt depending on the outer diameter of the coaxial cable with impedance matching) Accurate power adjustment is possible in 1W increments. (2) Frequency is 50MHz up and down of 2450MHz, that is, frequency modulation of 2450MHZ 50MHz (2400 ~ 2500 MHz range) is possible. (3) Longer lifespan than the magnetron method. (4) It is possible to embed a small isolator inside the power supply, and when a reflected wave is generated, the generator circuit is protected through immediate automatic reduction and interruption of the supplied power. (5) Small in volume and light in weight. (6) Accurate measurement of incident wave power and reflected wave power is possible. (6) Ripple is small and power transmission efficiency is high. (7) (There is a need to cover a large area, etc.) In case of an industrial application that requires a plurality of applicators, it is possible to achieve the user's purpose by optimizing it in various ways by making it light, thin and compact.

In the case of using a coaxial cable, although it is applied in the low power area of 300 ~ 500 Watt or less, a plan to improve this point is expected, and microwave transmission is possible even at higher power. In addition, even before a coaxial cable with a high maximum power tolerance comes out or another transmission method comes out, depending on the field of application, the microwave transmission device oscillated from each high-frequency semiconductor module is separated and installed into a plurality (refer to FIGS. 13 and 14). By distributing and transmitting microwaves of appropriate power (energy) required by the device, as well as individually controlling each high-frequency semiconductor power module, it is possible to fine-tune the application device. Accordingly, the present invention features and includes a transmission method and apparatus using a plurality of microwave power supplies, transmission lines, adapters, and the like.

Microwave refers to a region of electromagnetic waves with a frequency (frequency) of 300 MHz to 30 GHz and a wavelength of 1 cm to 1 m. The field of electromagnetic wave is arbitrarily divided by frequency, and the frequency is the number of times the wave vibrates in 1 second. The unit of frequency is Hz, and 1 Hz means that the wave vibrates once per second. The relationship between frequency (f), wavelength, and speed of light (C) is as follows.

= C/f(1)

That is, the shorter the wavelength, the higher the frequency, and the longer the wavelength, the lower the frequency. Here, the speed of light C is 2.99792458*10 ⁸ m/s.

According to the wavelength, electromagnetic waves are classified into gamma rays, x-rays, ultraviolet rays, visible rays, infrared rays, microwaves, radio waves, etc. That is, microwaves are radio waves with a lower frequency and longer wavelength than light, but have a higher frequency and shorter wavelength among radio waves, and are used in various industrial fields such as radar, navigation, communication and heating, plasma, etc. A transmission (tansmission) length Li for impedance matching is as follows.

Li = / 4 (2)

A microwave transmission adapter is manufactured by the above-described transmission length. Even when a semiconductor device is used to oscillate microwaves, a reflected wave may be generated due to an impedance mismatch. In a microwave device using a semiconductor device, since it is possible to change the frequency of the semiconductor device within a certain range, impedance matching can be performed by modulating the frequency according to (Equation 1) and (Equation 2), and in the present invention, impedance matching method. That is, the present invention is characterized in that the reflected wave is minimized by an algorithm that adjusts and tunes the frequency and matches the impedance when the applicator and the impedance do not match or when the Li does not match. That is, when it is generated and output from the semiconductor module, it is possible to modulate the frequency, so matching is possible through such frequency modulation, and this is called a Frequency Variation Tuning Method (FVMM). In summary, the present invention discloses a microwave system equipped with an impedance matching method in the form of frequency modulation (FVTM) as a method not using a conventional tuner (matcher). In this case, the microwave equipment is much simpler and easier can be used

In addition, in the case of connecting the semiconductor microwave power supply device and the applicator with a coaxial cable, additional tuning (matching) can be performed using a coaxial impedance adjusting device between them, and this can be performed using the coaxial or coaxial impedance tuner method (Co-Axial). Impedance Tuning Method). An example of installation of the coaxial impedance tuner 228 using this method is illustrated in FIG. 12 . It is installed between the semiconductor microwave generator 121 and the applicator 117 and is connected by a coaxial cable. The coaxial impedance tuner 228 is configured to change the impedance, which can be adjusted manually or automatically. That is, the magnitude of the reflected wave measured by the microwave detection sensor is displayed on the power supply device 121, and thereby the impedance of the coaxial impedance tuner 228 is automatically or manually adjusted to minimize the reflected wave. In the case of automatic tuning, it is revealed that the installation is possible to be embedded in the microwave power supply device 121 . The present invention includes a coaxial impedance tuning method in addition to the frequency modulation tuning method.

In addition, in the present invention, as another matching method, separate from the conventional method such as a 3-stub tuner (or 4-stub tuner) or the new matching method such as frequency modulation, a plunger is combined with an applicator to manually Alternatively, a method in which registration can be performed automatically is disclosed. The applicator 117 can be connected in the form of a waveguide or a coaxial cable, and a plunger 119 is installed behind the applicator 117 to be tuned and used. The plunger 119 is also available in a waveguide type or a coaxial cable type.

In summary, the present invention includes a method of using frequency modulation tuning, a coaxial impedance tuner 228 or a plunger 119 to minimize the reflected wave by impedance matching.

In addition, in the present invention, when an instantaneous reflected wave is generated, in order to protect the microwave generator from it, the isolator provided with a cooling line that protects the high frequency semiconductor module by diffracting the reflected wave is miniaturized and is embedded in the high frequency semiconductor power supply device. characterized in that

The concept of a plurality of semiconductor microwave generators is illustrated in FIG. 13 . A plurality of power modules (referred to as power supply, Power Module, PoM; 121) are installed, and an applicator (application device) is applied to each module. Each applicator may be an applicator as part of an overall applicator, or it may be an entirely separate and independent applicator. As illustrated in FIG. 10 , each power supply module has a respective control board, and a communication system capable of communicating with an external light exists. Therefore, it is possible to centrally control each power module in a Personal Computer PC (501) system or a PLC (Programmable Logic Controller; 501). For communication with the outside, there are Modbus RS232 / RS485 methods when using a PC, and Profibus or CanOpen methods when using PLC. The central control computer system 501 sets a desired power value for each power module 121, and each power module executes the search for optimizing the power of the set value. After each module is executed, the measured forward power and reflected wave power are transmitted to the central control computer system 501 through the communication gateway 233 . The central control computer system 501 receives these data values, displays them with the set values, compares and analyzes them, determines whether the desired specifications of the application device are met, and instructs the next command according to the optimization algorithm. Typically, a human machine display (HMI) display 505 is installed in the central control computer system 501 itself installed next to the micro-application device to monitor the operation status of each power module 121 in the field. When a micro-application device, which may be dangerous due to leakage, is installed in an isolated space, each of the plurality of power modules is The forward power, reflected wave power, and matching process trajectory curve are monitored on the Smith chart. Through the above method, the microwave application device can be made lighter, thinner and smaller, and since the microwave can be branched and used, it has a great advantage that it can be applied in various ways suitable for various purposes of the user at the same time.

An example of a device for transmitting microwaves using the plurality of semiconductor micro power modules is representatively illustrated in FIG. 14 . It is a very difficult field to generate a large-area plasma in order to maintain uniformity. In particular, a large-area plasma source for processing 12-inch or larger wafers or 5th to 8th generation LCDs is absolutely necessary. It is very difficult to make uniform large-area plasma using one microwave power supply and one applicator. In addition, when generating and using the shape of each reaction chamber, gas flow pattern, gas inlet, and radicals, it is necessary to control and supply plasma according to process conditions such as the shape of the radical distributor, and one large-area source It is almost impossible to match the desired uniformity and throughput (response speed). Therefore, there is a need for a method to make one large element by dividing it into multiple sources and configuring it. As shown in FIG. 14, the power of each power module is supplied to a coaxial rod wrapped in each insulator to form a linear plasma, but a plurality of these linear plasma antennas are installed to combine and configure a plasma source to form a large area. It constitutes a plasma (Large Area Plasma). In this case, since it is necessary to connect and use a plurality of power supply devices, there is a disadvantage in that it is complicated and expensive to configure the entire device. As a method to improve this, it is possible to transmit microwaves by a method of collectively processing linear plasma antennas in parallel and connecting them to a single coaxial rod (see Fig. do.

In the present invention, a new method and only some examples of a semiconductor microwave generating method and apparatus are disclosed, and individual applications such as plasma are to be specified in more detail as a separate invention and applied separately.

In addition to the method of using a plurality of high-frequency semiconductor power modules as in the case of the example of FIG. 14, a separate method of oscillating and transmitting microwaves using a conventional magnetron is also possible. In the case of a multi-linear plasma source (see FIG. 14) composed of several coaxial antennas, it is also possible to individually connect each microwave device to each coaxial rod. That is, in this case, as illustrated in FIG. 9, the final waveguide-coaxial cable conversion in each of several microwave power supplies with a magnetron, an isolator, a tuner (both ends are in the form of a waveguide), and a waveguide-coaxial cable conversion adapter. It is a method of connecting each coaxial cable through the connector of the adapter and connecting one-to-one to each coaxial rod of the linear plasma source. Therefore, in this case, each magnetron, isolator, tuner, and waveguide-coaxial cable conversion adapter must be connected to each coaxial rod and used. There are disadvantages.

In order to improve the above problem, it is possible to process by tying coaxial antennas of a linear plasma to be transmitted microwaves in parallel using one power supply device, a magnetron and a waveguide. In this case, the microwave transmitted to the magnetron and the waveguide is converted into a coaxial cable or coaxial rod form using a coaxial (cable)-waveguide conversion adapter, and then the coaxial rod of each linear plasma is connected in parallel to process it. This method is illustrated in FIG. 15 . When a vacuum is required to generate plasma, it is configured in a structure in which an O-ring or a metal gasket for vacuum is disposed on the surface of the coaxial rod arrangement plate to maintain a vacuum state. In addition, in order to minimize the influence of the metal rod on the application process (eg, the generation of process contaminants), the metal rod is wrapped around the metal rod with an insulating material and a material such as quartz or sapphire that can transmit microwaves. In addition, if necessary, a vacuum sealing adapter or the like is installed to maintain a vacuum at both ends of the metal rod and the insulating material.

In the above method, the microwave generated from one magnetron is connected in the order of waveguide -> waveguide-coaxial cable conversion adapter -> coaxial cable -> coaxial rod antenna, and a plurality of antennas of the line flat plasma source are assembled and the final coaxial connected in parallel. It is a method of transmitting by connecting to a rod. Separately from this method, it is possible to branch the waveguide using a waveguide splitter and then connect it individually to the coaxial rod of each linear plasma antenna or to connect it to a partially parallel set coaxial rod. That is, in this case, it is a method of connecting a waveguide -> waveguide splitter -> multiple waveguides-coaxial cable conversion adapter -> multiple coaxial cables -> multiple coaxial rod antennas. A case of connecting to a parallel set of coaxial rods is illustrated in FIG. 16 . However, in this case, since only one power is used, it is difficult to individually control and control the power supplied to each linear plasma and the electron temperature and electron density of each linear plasma accordingly. It is possible to use a coaxial cable splitter instead of a method using a waveguide splitter as one of the methods other than the above method. That is, it is a method of connecting the microwave generated from one magnetron with a waveguide -> waveguide-coaxial cable conversion adapter -> coaxial cable -> coaxial cable splitter -> multiple coaxial cables -> multiple coaxial rod antennas, and in the present invention It is pointed out that other embodiments that are variously modified and equivalent as described above are possible.

In the present invention, a method using a coaxial cable (Co-Axial Cable) or a waveguide has been mentioned, but the microwave transmission line method includes a Strip Line method or other method, and each line method according to the type of transmission line This includes adopting a conversion adapter suitable for

In summary, in the present invention, microwaves generated using one high power and a magnetron as described above are distributed in multiple using a conversion adapter, coaxial cable, and splitter, etc. including how to do it.

As described above, the present invention features a microwave application device that transmits microwaves generated by a high-frequency semiconductor device and a transmission line and an adapter through an adapter. Through this method, the weight and volume are smaller and the installation is easy. In addition, it is possible to transmit and control fine microwave energy with good uniformity and large area in various fields by separately installing and transmitting the plurality. In addition, in the present invention, even when generating and using microwaves using a conventional magnetron, microwaves are more easily individually, subset-parallel, or collective set-parallel processing using a waveguide-coaxial cable conversion adapter and a splitter, etc. A method of delivery has been disclosed.

The embodiments are merely exemplary, and those of ordinary skill in the art to which the present invention pertains will appreciate that various modifications and equivalent other embodiments are possible therefrom.

Therefore, it will be well understood that the present invention is not limited to the form mentioned in the above detailed description. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims. Moreover, it is to be understood that the present invention covers all modifications, equivalents and substitutions falling within the spirit and scope of the invention as defined by the appended claims.

111: magnetron 112: waveguide
113: circulator 115: 3-stub tuner
117: applicator 119: plunger or sliding short circuit
121: microwave power supply 131: cooling line
151: coaxial cable 153: connector
155: coaxial cable and wave guide conversion adapter
156: metal coaxial bar
157: insulating material such as quartz, sapphire or tempered glass
159: metal rod and insulating material vacuum sealing adapter
171: plasma 173: antenna
175: coaxial rod array plate for plasma generation
181: microwave splitter
161: [wafer, etc.] substrate) 165: holder with cooling line
221: automatic control board 223: semiconductor microwave generating module
225: AC-DC conversion inverter 231: power supply
233: External communication gateway 501: PC or PLC automatic control system
503: CPU or Cotroller Board 505: HMI Display
507: Multi-monitor

Claims (4)

microwave power supply;
a plurality of applicators to which microwaves are delivered;
a plurality of coaxial cables respectively connecting the microwave power supply and the plurality of applicators;
a plurality of first connectors mounted on the microwave power supply to connect each of the plurality of coaxial cables to the microwave power supply;
a plurality of second connectors mounted on the plurality of applicators to connect each of the plurality of coaxial cables to each of the plurality of applicators; and
A plurality of coaxial impedance tuners installed between each of the plurality of first connectors and the plurality of second connectors and connected to the plurality of coaxial cables to adjust the impedance of each of the plurality of coaxial cables and to minimize reflected wave power. including,
The microwave power supply is
a high-frequency semiconductor module that oscillates microwaves;
an AC-DC conversion inverter converting input AC power into DC and supplying power to the high-frequency semiconductor module;
a control board that regulates and supplies power and reduces or cuts off power when a reflected wave is generated; and
An isolator that diffracts the reflected wave to protect the high-frequency semiconductor module,
The high-frequency semiconductor module, the AC-DC conversion inverter, the control board and the isolator are embedded in the microwave power supply,
Each of the plurality of coaxial cables transmits the microwave oscillated from the microwave power supply to each of the plurality of applicators,
Impedances of the plurality of coaxial impedance tuners are automatically adjusted.
According to claim 1,
The microwave system further comprising a control algorithm that is embedded in the microwave power supply and modulates a frequency when a reflected wave is generated to minimize the reflected wave power.
According to claim 1,
The microwave system further comprising a plunger mounted on the applicator to minimize the reflected wave power.
According to claim 1,
The microwave system further comprising a coaxial conversion adapter for connecting the microwave power supply and the applicator.

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