RF power supply is a high frequency power supply which can generate sine wave with fixed frequency and has certain frequency. It is mainly composed of RF signal source, RF power amplifier and impedance matcher, and is a plasma matching power supply. Among them, RF power amplifier is considered as the core of RF power supply, so RF power amplifier is the key factor restricting the development of RF power supply.
According to different types of power amplifiers, RF power supply can be divided into tube RF power supply and transistor RF power supply. From tube RF power supply in 1980s to transistor RF power supply now, RF power supply has experienced a long development process. The power ranges from watts, hundred watts, kilowatts to megawatts, and the frequencies range from 2, 4, 13.56, 27.12, 40.68 MHz and 60MHz. At present, RF power supply is widely used in semiconductor process equipment, LED and solar photovoltaic industry, plasma generation in scientific experiments, RF induction heating, medical beauty and atmospheric plasma disinfection and cleaning, etc.
The development of RF power amplifier is relatively slow, and it was not until the appearance of electron tube in 1904 that it was officially applied to various fields. There are many problems in electron tube, its volume is too large, which limits the application of RF power supply of electron tube in some precision fields; Secondly, the life of tube RF power supply is less than half of that of transistor RF power supply; The most important thing is that its manufacturing process is very complicated. Compared with electronic tubes, transistor RF power supply is much smaller in size, low in loss, long in life and produces little heat. Therefore, with the development of transistors, electronic tubes are gradually eliminated.
Figure1: RF plasma generator
Main characteristics of semiconductor RF power supply industry development
With the development of power electronics technology, RF power supply has developed from tube power supply to transistor RF power supply. As a typical representative of the third generation of wide band gap semiconductor materials GaN has the advantages of wide band gap high critical breakdown field high electron saturation drift velocity and high conduction of AlGaN/GaN heterojunction two-dimensional electron gas 2DEG. Compared with silicon power devices, GaN power devices have the characteristics of low conduction impedance and small input/output capacitance, which make GaN power devices have high switching speed and low loss. Based on Class E power RF power supply, an experimental prototype of all-solid-state RF power supply with 4 MHz switching frequency and adjustable power is designed and manufactured by using GaN power devices. Through the design and optimization of the circuit, when the output power of the prototype is 21.4 W, the efficiency reaches 96.7%; At the same time, GaN devices on the prototype are replaced by Si power devices specially produced for RF power supply. Experimental data verify that GaN devices have fast switching speed and low loss, which can greatly improve the efficiency of RF power supply.
RF power supply is generally composed of RF signal generator, RF power amplifier circuit, power supply line and RF power detector. According to the core components of amplification circuit, it can be divided into tube-type RF power supply and solid-state RF power supply, in which tube-type RF power supply uses tube as power amplification element, while solid-state RF power supply uses transistor as power amplification element. At present, the products of domestic manufacturers are mainly tube-type RF power supply. Although it has great impedance mismatch tolerance, it can only be used as a component in general teaching and scientific research equipment because of its shortcomings such as easy aging, unstable output power and high working voltage. Foreign mainstream manufacturers, such as Advance Energy, XP Power Company and MKS INSTRUMENTS, all use transistors as power amplification components, and the solid-state RF power supply provided by them has been widely used in mainstream semiconductor process production lines.
With the development of digital power supply, the control unit of power supply is connected with RF clock generator unit and voltage adjustable DC power supply respectively. The output of RF clock generator unit and voltage adjustable DC power supply are connected with power amplification unit. After the power output of power amplification unit is synthesized by power synthesizer, the incident power and reflected power are measured by directional coupler, and the measurement signal output of directional coupler is connected with control unit. The power supply controls the RF power output by adjusting the height and width of the driving pulse of the power driving stage, which has high working efficiency and reliable control. Moreover, the important working parameters of the power supply can be collected and analyzed in real time by the main CPU in the control unit, and the control parameters can be set by the main CPU in the control unit. If the parameters are abnormal, the power supply can be protected in time, thus greatly improving the working efficiency and reliability of the RF power supply.
General development of semiconductor RF power supply industry
Semiconductor RF power supply is a high frequency power supply which can generate sine wave with fixed frequency and has certain frequency. It is mainly composed of RF signal source, RF power amplifier and impedance matcher. RF power supply is used as plasma matching power supply, and its frequency is within RF range. Widely used in semiconductor etching, CVD, PCV and other fields.
At present, there is still a certain gap between the RF power supply used in advanced plasma equipment in China and similar power supply abroad. To catch up with the international level, a lot of work needs to be done:
Most of the RF power supplies in our country are electronic tubes or hybrid circuits of electronic tubes and transistors, which are large in size and limit their application. And most of the transistors used are imported from abroad, so it is necessary to develop our own core transistors, develop new technologies and new components, and make the RF power supply miniaturized
The manual impedance matcher is used in our country, which is easily affected by environmental factors, while the automatic impedance matcher has been used abroad, which plays an important role in the field of industrial automation. Therefore, the automatic impedance matcher with high precision and high speed is an inevitable trend in the future development.
Compared with foreign RF power supply, the types of RF power supply in China are relatively single, and different types of RF power supply such as broadband power supply, microwave power supply and highly power RF power supply should be developed in the future.
Figure2: Sales and growth rate of global semiconductor RF power supply market
According to statistics, the global sales of semiconductor RF power supply market reached 726 million US dollars in 2022, and is expected to reach 1.457 billion US dollars in 2029, with a compound annual growth rate of 11.18%. At the regional aspect, China's market has changed rapidly in the past few years. In 2022, the market size is 96.6 million US dollars, accounting for 13.31% of the world. It is expected to reach 188.52 million US dollars in 2029, when the global proportion is 12.94%. In the next few years, the important market position of the Asia-Pacific region will become more prominent. Besides China, Japan, South Korea, India and Southeast Asia will also play an important role. In addition, Germany is expected to continue to maintain its leading position in Europe in the next six years.
From the production side, North America and Japan are two important production regions, accounting for 36.04% and 23.17% of the market share respectively in 2022. It is expected that China will maintain the fastest growth rate in the next few years, and its share is expected to reach 11.71% in 2029. In terms of product types, 13.56 MHz occupies an important position, and its share is expected to reach 32.1% in 2029, followed by 27.12 MHz. At the same time, in terms of application, the share of etching is about 36.56% in 2022, and CAGR is about 11.09% in the next few years.
From the manufacturer's point of view, the core manufacturers of semiconductor RF power supply in the world mainly include MKS INSTRUMENTS, Advance Energy OSAKAHENATSUKICO Co., Ltd., XP Power and TRUMPF, etc. In 2022, the world's first echelon manufacturers mainly include MKS INSTRUMENTS, Advance Energy and OASKAHENATSUKICO Co., Ltd., and the first echelon has a market share of about 52.95%; The second echelon manufacturers include TRUMPF, COMET PCT, KYOSANM Electric Co., Ltd., Beijing BBEF Science & Technology, ULVAC, JEOL Co., Ltd., Ad tec Plasma Technology, New Power Plasma, etc., with a total share of 33.99%.
Transistors May Replace Tubes: Market Research Report of Semiconductor RF Power Supply in 2023-China.exportsemi.com
