Abstract strong support 863 aid of, CVD diamond film study our country in terms of tools, heat sink and optical applications have made very significant progress, not only significantly narrowed the gap with the advanced industrialized countries, and has led China began to enter Industrial application process. At present, there are some small high-tech companies and enterprises in China, but most of them are limited to diamond thick film tools (diamond thick film brazing tools and diamond wire drawing cores). Substantial progress has been made in the research of diamond thin film coating tools, diamond film heat sinks and diamond optical applications. Although there is still a certain distance from industrial application, it has the conditions for industrial development and market application. This paper discusses the industrialization prospects and current problems of CVD diamond films in China, and puts forward some suggestions.
Key words diamond film; chemical vapor deposition; industrial application 1 chemical vapor deposition CVD diamond film research chemical vapor deposition diamond film research has been widely recognized in the world for more than ten years, and once set off the so-called "diamond heat" sweeping the world (Diamond Pever)". Half of the reason is due to scientific curiosity. The initial research results of diamonds only from methane and hydrogen are common to many people like “point stone into goldâ€, but the main reason is the combination of many extreme properties of diamond. The extremely attractive application prospects shown (due to the fact that diamond is the most closely bonded substance).
The study of chemical vapor deposited diamond films dates back to the 1950s, but it was not until the late 1970s and early 1980s that the contributions of Japanese scholars began to show the possibility of practical application. Although the so-called "diamond fever" began to form in the mid-1980s, the real progress was made after the entry into the Q0 era, and the screening was made after 1993. Theoretically speaking, through the efforts of nearly ten years, the mechanism of chemical vapor deposition of diamond film has been basically clarified. A large number of experimental studies, especially those conducted using a variety of diagnostic methods, have clarified the chemical environment and surface processes of diamond vapor deposition. There has been a deeper understanding of the nucleation and growth process of diamond on heterogeneous substrates. Theoretical models and calculations also show good agreement with experimental results. However, the surface chemistry for diamond chemical vapor deposition is still not as clear as the gas phase process.
In a technical sense, the progress in the past ten years has mainly been reflected in the rapid increase in the deposition rate and quality of CVD diamond films and the significant reduction in production costs. Compared with the mid-1980s, the deposition rate of diamond film is increased by nearly 1000 times, and the manufacturing cost is correspondingly reduced to 1/10000. This is mainly due to the successful development of large-area, high-growth deposition equipment and processes and In-depth understanding of the mechanism of diamond chemical vapor deposition. At the same time, remarkable progress has been made in the preparation of high-quality diamond films. The "optical grade diamond film" that has appeared since the mid-1990s is of sufficient quality and the highest quality natural type IIa gem-quality diamond single crystal. Compared with almost all physical and chemical properties, it is comparable to mechanical properties, especially mechanical strength and natural diamond single crystals (almost an order of magnitude lower).
At the same time, the application research and industrialization of CVD diamond films have also made remarkable progress. CVD diamond film tools have appeared in domestic and foreign markets, although the current market size is not large, but has shown excellent market prospects. Diamond film heat sinks have begun to be marketed on high-power semiconductor laser diodes, in the packaging of large-scale integrated circuit three-dimensional assembly technology (MCMs-Multi Chip Modules), semiconductor devices (especially high-power and high-frequency devices). The application has made substantial progress, showing broad market application prospects and has formed a market of at least tens of millions of dollars. In optical applications, with the advent of extremely high quality optical grade diamond films, the market application of diamond film optics has also been mentioned on the agenda. In addition to the early X-ray window, in recent years, infrared thermal imaging device windows, high-speed interceptor missile hoods, strong laser windows, high-power microwave windows, etc. have been achieved or are near practical levels. Since the actual market size cannot be understood due to military applications in many occasions, a diamond film flat window (worth 100,000 mark) having a diameter of F1OOmm has been commercially available in foreign markets. Although no breakthrough has been made in the heteroepitaxial growth of diamond films, n-type doping is not ideal, but great progress has been made in the electronic applications of diamond films. Particle detectors made of extremely high quality diamond films have performance parameters (collection distance LC) that exceed the highest quality natural type IIa diamond single crystals. In addition, the performance of various diamond film detectors and sensors is constantly improving, and it is likely to form a considerable market. Of particular note is the application of diamond films in vacuum microelectronic devices and surface acoustic wave devices (SAW). The former utilizes the excellent field emission properties of diamond films to produce all-solid-state high-performance flat panel displays, while the latter may be used to make high-bandwidth (up to 4GHz-6GHz) filters, thereby greatly improving future mobile phone communication. performance. Demonstrative diamond film flat panel display devices have appeared abroad, and commercial diamond film SAW devices have also appeared. The market prospects for these applications are excellent, with only diamond film display devices, and experts predict that it will be possible to achieve a billion-dollar market in recent years.
2 China's CVD diamond film research progress and industrialization status and existing problems China's 863 program from the "seventh five-year" plan to establish a special support for the research and development of CVD diamond film, has funded dozens of research and development projects, and in the "eight During the period of the 5th and 9th Five-Year Plan, special major (key technology) projects were set up to promote the industrialization of diamond films. The Natural Science Foundation also funded more than 20 fund projects on CVD diamond films during the Eighth and Ninth Five-Year Plan, including two major projects. After more than ten years of hard work, China has made great progress in the preparation, processing and application of CVD diamond films, which has significantly narrowed the gap with foreign countries.
In the preparation technology of diamond film, through more than ten years of efforts, large area, high quality has been formed in hot wire CVD (EACVD), hot cathode CVD and DC Arc Plasma Jet CVD. The preparation ability and preliminary processing ability of the diamond self-supporting film laid the foundation for the industrial application of the diamond film. Especially in the high-power DC Arc Plasma Jet CVD equipment, with the support of the key technologies of the 863 Program “Eighth Five-Year Planâ€, a 100kW-class high-power system with Chinese characteristics and independent intellectual property rights has been developed. A large-area, long-channel magnetron/hydrodynamic rotary arc plasma torch is used to prepare large-area optical grade, heat sink grade and tool-grade diamond self-supporting membranes under gas cycling conditions. This technology has been valued by foreign counterparts and has won a place in the field of CVD diamond film research in China. At the same time, there has been a lot of progress in the application of tools, heat sinks, optics and electronics (electronics). Finally, at the end of the last century, China began to enter the industrialization stage in CVD diamond film research.
At present, China has obtained limited market applications only in diamond thick film tools. The earliest established diamond film industry was Beijing Tiandi Diamond Co., Ltd., which was invested by Nanjing Tiandi Group and relied on the major project technology of the 863 Program. It was established in 1996 with the Beijing Institute of Artificial Crystals. The company is mainly engaged in various CVD diamond thick film brazing tools, diamond film drawing die cores, various friction and wear applications (such as high-precision bearing brackets, diamond wheel dressing pens, etc.), it is said to also operate PCD (diamond polycrystalline) Tools and materials. The company spent the second half of 2000 on the investment-profit turning point and entered a period of steady development, but the market size is still small. In addition to Beijing Tiandi Company, the 9th Institute of Nuclear Industry, the Hebei Academy of Sciences (cooperating with Beijing University of Science and Technology), the Ningxia Machinery Research Institute (cooperating with Beijing University of Science and Technology), the Yellow River Group Company (cooperating with Jilin University) and Zhejiang University are also Production and sales of CVD diamond thick film tool products, mainly diamond wire drawing mold core, but the market size is still small.
Although the performance of diamond thick film tool is better than PCD, due to the high cost of preparation and processing, and limited to making simple shape tools, it faces fierce competition from PCD. It can only be displayed in ultra-precision and efficient processing tools and extreme friction and wear. Advantage. The diamond film drawing die core has quasi-isotropic properties due to the polycrystalline structure of the diamond film, which makes it significantly better than PCD, and may even exceed the diamond single crystal, so it has a good market prospect. It is estimated that the domestic market capacity is about 500 million yuan, and the domestic market share of CVD diamond wire drawing die cores is less than 1%. The main problems are as follows: (1) The current diamond self-supporting film is still low in strength and the dispersion of strength is large, which causes the product quality to fluctuate greatly, which seriously affects the establishment of user reputation; (2) Market for CVD diamond film The product still does not understand, it takes time to enter the market.
In contrast, diamond film coating tools are inexpensive to produce, and performance is close to that of PCD, even exceeding PCD, plus tools that can be used in complex shapes such as twist drills, end mills, milling cutters, and chipbreakers. The marketable prospects are excellent in the direct deposition of diamond film on the indexable inserts, etc., and the ease of industrial mass production. At present, great progress has been made in improving the adhesion of diamond films on cemented carbide substrates. Although there is still much room for improvement, conditions for the development of practical diamond film coated cemented carbide tools have been established. At present, the technical obstacles to the industrialization of diamond film coated cemented carbide tools in China are: (1) the adhesion of diamond coatings needs to be further improved; (2) the urgent need to develop industrialized diamond film tool coating equipment suitable for industrial production. And corresponding supporting industrial production technology; (3) need to solve product quality inspection and quality control technology in industrial production; (4) need to carry out product development and market development of diamond film coating for the specific situation of the domestic market.
In addition to a large number of high-silicon aluminum alloy components that the automotive industry needs to process, various difficult-to-machine materials in the defense industry, such as various non-ferrous metals, composite materials, ceramics, polymer materials, and inorganic non-metallic materials, are hard coated with diamond. The quality of the alloy tool has obvious advantages, and its technical economy is far superior to PCD and natural diamond tools. In addition, the diamond film coating tool has two applications with excellent market application prospects: one is a diamond film coated carbide micro drill; the other is a diamond film coated carbide tool. At present, China has become a major producer of semiconductor integrated circuit boards, with an annual output value of more than 40 billion yuan, and continues to rise at an annual growth rate of more than 10%. Modern integrated circuit boards are made of fiber-reinforced composite materials and use a multi-layer copper wiring process, which is very abrasive to the hard alloy drill bits, resulting in the consumption of hard alloy micro drills accounting for 15% of the total output value of the board. %about. Diamond film coated carbide micro drills will not only solve the urgent needs of China's integrated circuit board manufacturers, but also bring great economic benefits. In modern furniture and woodworking factories, the demand for mechanized processing of hardwood furniture and super-hard coated composite flooring is increasing, and the key is the combination tool for woodworking. Most of these tools are imported, the price is very high, and the service life is very short. Some tools can be reground, but must be sent abroad by the manufacturer. Therefore, it also provides another world of diamond film coating tools that can show your skills.
In recent years, with the support of major projects of the 863 Program, domestically, great progress has been made in the preparation technology of optical grade diamond self-supporting membranes. Beijing University of Science and Technology successfully produced optical grade (transparent) diamond self-supporting film for the first time in China at the end of 1997 by high-power DC Arc Plasma Jet CVD process, from ultraviolet (0.22mm) to microwave band except for the intrinsic absorption peak at 4mm-6mm. There is no other absorption peak outside, the transmittance in the whole infrared band is about 70%, and the thermal conductivity is as high as 19W/cm·K, which is close to the natural type IIa gem-quality diamond single crystal. Optical grade diamond self-supporting film not only has a very important application prospect in the military, but also can be used as a high Mach number flying missile infrared window and hood, high power microwave window (Gyrotron), satellite optical window, and also has an excellent market for civilian use. Application prospects. One of the most important applications is the high-power industrial CO2 laser window, which not only replaces the currently used ZnSe and GaAs windows, but also greatly improves the quality of the output beam of industrial CO2 laser processing machines, thereby improving and improving the quality and level of laser processing. It will promote technological advancement in the entire laser processing industry (using a diamond window to allow higher power laser output, promote the development of high-power CO2 lasers, and further enhance laser processing capabilities). In addition, high-end consumer goods such as the high-end "diamond case" may also have unexpected market prospects. Although there is still a big gap compared with foreign countries, China has begun to have the ability of market application research and development in diamond optics applications.
The domestic research and development of the thermal application of diamond film began in the “Eighth Five-Year Planâ€. The main application target is the high-power laser diode array heat sink. However, due to some related technical problems, such as the polishing and metallization of the diamond film and the compatibility with the device semiconductor process, the industrial application has not yet been realized. However, in recent years, China has made great progress in the preparation of large-area high thermal conductivity grade diamond self-supporting membranes, and has the ability to prepare diamond heat of various thermal conductivity grades of 8w/cm·K-19W/cm·k. Sinking. In recent years, the demand for diamond heat sink sheets has been increasing in foreign countries, and China has a very obvious cost advantage in the preparation of diamond heat sink sheets. Whether it is hot wire CVD, hot cathode CVD or high-power DC Arc Plasma Jet CVD, it is possible to supply various specifications of heat sink sheets to foreign markets at a price equivalent to only 1/2-1/3 of foreign countries. Wire CVD and hot cathode CVD can only prepare heat sink sheets of 15 W/cm·K or less, and DC Arc Plasma Jet CVD is required for higher heat conductivity grade heat sink sheets. However, at present, the domestic equipment level is still unable to meet the production requirements of large-volume diamond heat sink sheets, and it is necessary to develop large-area high-quality diamond self-supporting film deposition equipment suitable for industrial mass production. In addition to high-power laser diode arrays, diamond film heat sinks are also used abroad for diamond packaging of MCMs (multi-chip 3D assembly technology) and power semiconductor devices (Power ICs). The extremely high thermal conductivity of the diamond film makes it a very good application prospect in terms of miniaturization and miniaturization of the device. For foreign countries, the main technical obstacles at present are the cost of preparation and processing of diamond films. If the domestic ability to provide various thermal conductivity grades of cheap diamond film heat sink wafers to foreign markets in the last 2 to 3 years, It is possible to quickly enter the international market and maintain strong competitiveness.
Domestic research on diamond film active electronic devices, diamond film detectors and sensors, and electrochemical applications of diamond films has not made much progress. However, in recent years, research on cold cathode field emission and vacuum microelectronic devices, surface acoustic wave devices (SAW) and the like has been quite active. However, there is no small gap compared with foreign countries, especially in device development and practical application research and development.
Nano-diamond film is a new hot spot in the research field of CVD diamond film which has appeared in recent years. Compared to a conventional diamond film (also referred to as a microcrystalline diamond film having a grain size of from 0.3 μm to several hundreds μm), the nanodiamond film has a grain size of only 0.2 μm to several nm. Therefore, the surface of the nano-diamond film is extremely smooth and flat, the surface roughness can be below Ra 20nm, and the friction coefficient is only 0.06-0.1, which is lower than the usual micro-diamond film (about 0.1). The grain boundary of the nano-diamond film is composed of sp2 hybridized carbon atoms. The electrical properties of the nano-diamond film are quite different from those of the micro-diamond film in the presence of a large number of grain boundaries. The resistivity of the nano-diamond film and the boron-doped micro-diamond film Quite, and it has extremely excellent cold cathode field emission properties and electrochemical properties. Nano-diamond films may have advantages over ordinary micro-diamond films in many high-tech fields such as diamond coating tools, friction and wear, field emission, MEMS (micro-electromechanical systems), important infrared optical material protective coatings and electrochemistry. At present, many units in China are already carrying out relevant research and development work, and have made gratifying research progress.
3 Suggestions on the industrialization of CVD diamond film in China;
Based on the above-mentioned situation and the characteristics of China's (especially Beijing) technical and economic development and the existing research and development basis, it is recommended that:
(1) In order to adapt to the rapid development of the automotive industry, electromechanical and defense industries in Beijing, it is recommended to support the industrialization of diamond film coated cemented carbide tools. The focus should be on:
1 diamond film coated cemented carbide tool industrial coating equipment (single equipment annual production capacity: diamond coated carbide inserts or drill bits more than 100,000) and supporting industrial production technology research and development;
2 Diamond film coated cemented carbide tool quality monitoring and control technology research and development; 3 key product development and industrial production technology research and development:
A. Precision cutting tools for high-efficiency precision machining of high-silicon aluminum alloys and various difficult-to-machine materials (composites, ceramics, polymer materials) for the automotive industry and the defense industry;
B. Diamond film coated carbide micro drills for integrated circuit board processing (drilling) and industrial production technology development;
C. Diamond film coating woodworking tools and industrial production technology research and development. (2) In order to adapt to the rapid development of microelectronics and optoelectronic technology in China and Beijing, and the trend of miniaturization of devices, it is recommended that: 1 R & D can be used for large-area (F100mm or more) optical grade, heat sink grade and tool grade diamond self-supporting film batch Production of industrialized diamond film deposition equipment (single equipment annual production of diamond white film (tool-level) capacity of about 30,000 carats) and the corresponding production technology, as soon as possible (competing in about 2 years) to establish the first to provide the above products to foreign markets in bulk Industrialized production capacity; 2 research on MCMs technology and power semiconductors (Power ICs) diamond packaging technology using high thermal conductivity diamond substrates, promoting the miniaturization and upgrading of microelectronics and optoelectronic devices, and forming market applications; 3 using diamond film substrates Research on surface acoustic wave devices to develop a new generation of high-performance mobile communication technologies.
(3) Research and develop high-power industrial CO2 laser window products and industrial production technology, provide cheap optical grade diamond white support film window to domestic and foreign markets, and promote technological progress in domestic laser processing industry;
(4) Conduct research on preparation, characterization and application development of nano-diamond films, and encourage the application of nano-diamond films in high-tech fields such as tools, friction and wear, MEMS, field emission flat panel display and optical coating.
4 Conclusion In the past ten years, CVD diamond film technology research has made tremendous progress, and has begun to enter the industrial application stage in some application fields such as tools, thermals and optics. At home and abroad, some emerging diamond film industries have emerged.
According to the domestic technology development status and the domestic (Beijing area) technical and economic development characteristics, in addition to the existing diamond self-supporting film tools (and friction and wear) applications, diamond film coating tools and diamond heat sink substrates are likely to be in the near future. Industrialization is achieved and the market prospects are better. Optical grade diamond self-supporting film industrial CO2 laser window, diamond package with high thermal conductivity diamond substrate MCMs and power semiconductors (Power ICs), field emission display device and surface acoustic wave device (SAW) and nanodiamond film applications Will enter the market one after another. The industrialization of diamond film will not only produce huge market economic benefits, but also may have a profound impact on the development of many high-tech fields in China and Beijing and the technological progress of related industries. In addition to the unremitting efforts of the relevant government departments and the unremitting efforts of the vast number of scientific and technological personnel, the realization of the above project objectives requires the active participation of people of insight in the business community. The progress made in the field of CVD diamond film research in recent years is indeed undoubted. Compared with the past few years, the current technology is closer to the market application, and although there are still some risks, it has reached a level that can be predicted and tolerated. Because the application of diamond film is very broad, the risk in the field of diamond film industrialization will not be catastrophic. For those who want to get involved in industrial development in this field, the key is to have a good quality. R&D team and a strong R&D base (center). Therefore, in the future construction of the diamond film emerging industry, the model of “production, learning and research†is still the best choice.
Key words diamond film; chemical vapor deposition; industrial application 1 chemical vapor deposition CVD diamond film research chemical vapor deposition diamond film research has been widely recognized in the world for more than ten years, and once set off the so-called "diamond heat" sweeping the world (Diamond Pever)". Half of the reason is due to scientific curiosity. The initial research results of diamonds only from methane and hydrogen are common to many people like “point stone into goldâ€, but the main reason is the combination of many extreme properties of diamond. The extremely attractive application prospects shown (due to the fact that diamond is the most closely bonded substance).
The study of chemical vapor deposited diamond films dates back to the 1950s, but it was not until the late 1970s and early 1980s that the contributions of Japanese scholars began to show the possibility of practical application. Although the so-called "diamond fever" began to form in the mid-1980s, the real progress was made after the entry into the Q0 era, and the screening was made after 1993. Theoretically speaking, through the efforts of nearly ten years, the mechanism of chemical vapor deposition of diamond film has been basically clarified. A large number of experimental studies, especially those conducted using a variety of diagnostic methods, have clarified the chemical environment and surface processes of diamond vapor deposition. There has been a deeper understanding of the nucleation and growth process of diamond on heterogeneous substrates. Theoretical models and calculations also show good agreement with experimental results. However, the surface chemistry for diamond chemical vapor deposition is still not as clear as the gas phase process.
In a technical sense, the progress in the past ten years has mainly been reflected in the rapid increase in the deposition rate and quality of CVD diamond films and the significant reduction in production costs. Compared with the mid-1980s, the deposition rate of diamond film is increased by nearly 1000 times, and the manufacturing cost is correspondingly reduced to 1/10000. This is mainly due to the successful development of large-area, high-growth deposition equipment and processes and In-depth understanding of the mechanism of diamond chemical vapor deposition. At the same time, remarkable progress has been made in the preparation of high-quality diamond films. The "optical grade diamond film" that has appeared since the mid-1990s is of sufficient quality and the highest quality natural type IIa gem-quality diamond single crystal. Compared with almost all physical and chemical properties, it is comparable to mechanical properties, especially mechanical strength and natural diamond single crystals (almost an order of magnitude lower).
At the same time, the application research and industrialization of CVD diamond films have also made remarkable progress. CVD diamond film tools have appeared in domestic and foreign markets, although the current market size is not large, but has shown excellent market prospects. Diamond film heat sinks have begun to be marketed on high-power semiconductor laser diodes, in the packaging of large-scale integrated circuit three-dimensional assembly technology (MCMs-Multi Chip Modules), semiconductor devices (especially high-power and high-frequency devices). The application has made substantial progress, showing broad market application prospects and has formed a market of at least tens of millions of dollars. In optical applications, with the advent of extremely high quality optical grade diamond films, the market application of diamond film optics has also been mentioned on the agenda. In addition to the early X-ray window, in recent years, infrared thermal imaging device windows, high-speed interceptor missile hoods, strong laser windows, high-power microwave windows, etc. have been achieved or are near practical levels. Since the actual market size cannot be understood due to military applications in many occasions, a diamond film flat window (worth 100,000 mark) having a diameter of F1OOmm has been commercially available in foreign markets. Although no breakthrough has been made in the heteroepitaxial growth of diamond films, n-type doping is not ideal, but great progress has been made in the electronic applications of diamond films. Particle detectors made of extremely high quality diamond films have performance parameters (collection distance LC) that exceed the highest quality natural type IIa diamond single crystals. In addition, the performance of various diamond film detectors and sensors is constantly improving, and it is likely to form a considerable market. Of particular note is the application of diamond films in vacuum microelectronic devices and surface acoustic wave devices (SAW). The former utilizes the excellent field emission properties of diamond films to produce all-solid-state high-performance flat panel displays, while the latter may be used to make high-bandwidth (up to 4GHz-6GHz) filters, thereby greatly improving future mobile phone communication. performance. Demonstrative diamond film flat panel display devices have appeared abroad, and commercial diamond film SAW devices have also appeared. The market prospects for these applications are excellent, with only diamond film display devices, and experts predict that it will be possible to achieve a billion-dollar market in recent years.
2 China's CVD diamond film research progress and industrialization status and existing problems China's 863 program from the "seventh five-year" plan to establish a special support for the research and development of CVD diamond film, has funded dozens of research and development projects, and in the "eight During the period of the 5th and 9th Five-Year Plan, special major (key technology) projects were set up to promote the industrialization of diamond films. The Natural Science Foundation also funded more than 20 fund projects on CVD diamond films during the Eighth and Ninth Five-Year Plan, including two major projects. After more than ten years of hard work, China has made great progress in the preparation, processing and application of CVD diamond films, which has significantly narrowed the gap with foreign countries.
In the preparation technology of diamond film, through more than ten years of efforts, large area, high quality has been formed in hot wire CVD (EACVD), hot cathode CVD and DC Arc Plasma Jet CVD. The preparation ability and preliminary processing ability of the diamond self-supporting film laid the foundation for the industrial application of the diamond film. Especially in the high-power DC Arc Plasma Jet CVD equipment, with the support of the key technologies of the 863 Program “Eighth Five-Year Planâ€, a 100kW-class high-power system with Chinese characteristics and independent intellectual property rights has been developed. A large-area, long-channel magnetron/hydrodynamic rotary arc plasma torch is used to prepare large-area optical grade, heat sink grade and tool-grade diamond self-supporting membranes under gas cycling conditions. This technology has been valued by foreign counterparts and has won a place in the field of CVD diamond film research in China. At the same time, there has been a lot of progress in the application of tools, heat sinks, optics and electronics (electronics). Finally, at the end of the last century, China began to enter the industrialization stage in CVD diamond film research.
At present, China has obtained limited market applications only in diamond thick film tools. The earliest established diamond film industry was Beijing Tiandi Diamond Co., Ltd., which was invested by Nanjing Tiandi Group and relied on the major project technology of the 863 Program. It was established in 1996 with the Beijing Institute of Artificial Crystals. The company is mainly engaged in various CVD diamond thick film brazing tools, diamond film drawing die cores, various friction and wear applications (such as high-precision bearing brackets, diamond wheel dressing pens, etc.), it is said to also operate PCD (diamond polycrystalline) Tools and materials. The company spent the second half of 2000 on the investment-profit turning point and entered a period of steady development, but the market size is still small. In addition to Beijing Tiandi Company, the 9th Institute of Nuclear Industry, the Hebei Academy of Sciences (cooperating with Beijing University of Science and Technology), the Ningxia Machinery Research Institute (cooperating with Beijing University of Science and Technology), the Yellow River Group Company (cooperating with Jilin University) and Zhejiang University are also Production and sales of CVD diamond thick film tool products, mainly diamond wire drawing mold core, but the market size is still small.
Although the performance of diamond thick film tool is better than PCD, due to the high cost of preparation and processing, and limited to making simple shape tools, it faces fierce competition from PCD. It can only be displayed in ultra-precision and efficient processing tools and extreme friction and wear. Advantage. The diamond film drawing die core has quasi-isotropic properties due to the polycrystalline structure of the diamond film, which makes it significantly better than PCD, and may even exceed the diamond single crystal, so it has a good market prospect. It is estimated that the domestic market capacity is about 500 million yuan, and the domestic market share of CVD diamond wire drawing die cores is less than 1%. The main problems are as follows: (1) The current diamond self-supporting film is still low in strength and the dispersion of strength is large, which causes the product quality to fluctuate greatly, which seriously affects the establishment of user reputation; (2) Market for CVD diamond film The product still does not understand, it takes time to enter the market.
In contrast, diamond film coating tools are inexpensive to produce, and performance is close to that of PCD, even exceeding PCD, plus tools that can be used in complex shapes such as twist drills, end mills, milling cutters, and chipbreakers. The marketable prospects are excellent in the direct deposition of diamond film on the indexable inserts, etc., and the ease of industrial mass production. At present, great progress has been made in improving the adhesion of diamond films on cemented carbide substrates. Although there is still much room for improvement, conditions for the development of practical diamond film coated cemented carbide tools have been established. At present, the technical obstacles to the industrialization of diamond film coated cemented carbide tools in China are: (1) the adhesion of diamond coatings needs to be further improved; (2) the urgent need to develop industrialized diamond film tool coating equipment suitable for industrial production. And corresponding supporting industrial production technology; (3) need to solve product quality inspection and quality control technology in industrial production; (4) need to carry out product development and market development of diamond film coating for the specific situation of the domestic market.
In addition to a large number of high-silicon aluminum alloy components that the automotive industry needs to process, various difficult-to-machine materials in the defense industry, such as various non-ferrous metals, composite materials, ceramics, polymer materials, and inorganic non-metallic materials, are hard coated with diamond. The quality of the alloy tool has obvious advantages, and its technical economy is far superior to PCD and natural diamond tools. In addition, the diamond film coating tool has two applications with excellent market application prospects: one is a diamond film coated carbide micro drill; the other is a diamond film coated carbide tool. At present, China has become a major producer of semiconductor integrated circuit boards, with an annual output value of more than 40 billion yuan, and continues to rise at an annual growth rate of more than 10%. Modern integrated circuit boards are made of fiber-reinforced composite materials and use a multi-layer copper wiring process, which is very abrasive to the hard alloy drill bits, resulting in the consumption of hard alloy micro drills accounting for 15% of the total output value of the board. %about. Diamond film coated carbide micro drills will not only solve the urgent needs of China's integrated circuit board manufacturers, but also bring great economic benefits. In modern furniture and woodworking factories, the demand for mechanized processing of hardwood furniture and super-hard coated composite flooring is increasing, and the key is the combination tool for woodworking. Most of these tools are imported, the price is very high, and the service life is very short. Some tools can be reground, but must be sent abroad by the manufacturer. Therefore, it also provides another world of diamond film coating tools that can show your skills.
In recent years, with the support of major projects of the 863 Program, domestically, great progress has been made in the preparation technology of optical grade diamond self-supporting membranes. Beijing University of Science and Technology successfully produced optical grade (transparent) diamond self-supporting film for the first time in China at the end of 1997 by high-power DC Arc Plasma Jet CVD process, from ultraviolet (0.22mm) to microwave band except for the intrinsic absorption peak at 4mm-6mm. There is no other absorption peak outside, the transmittance in the whole infrared band is about 70%, and the thermal conductivity is as high as 19W/cm·K, which is close to the natural type IIa gem-quality diamond single crystal. Optical grade diamond self-supporting film not only has a very important application prospect in the military, but also can be used as a high Mach number flying missile infrared window and hood, high power microwave window (Gyrotron), satellite optical window, and also has an excellent market for civilian use. Application prospects. One of the most important applications is the high-power industrial CO2 laser window, which not only replaces the currently used ZnSe and GaAs windows, but also greatly improves the quality of the output beam of industrial CO2 laser processing machines, thereby improving and improving the quality and level of laser processing. It will promote technological advancement in the entire laser processing industry (using a diamond window to allow higher power laser output, promote the development of high-power CO2 lasers, and further enhance laser processing capabilities). In addition, high-end consumer goods such as the high-end "diamond case" may also have unexpected market prospects. Although there is still a big gap compared with foreign countries, China has begun to have the ability of market application research and development in diamond optics applications.
The domestic research and development of the thermal application of diamond film began in the “Eighth Five-Year Planâ€. The main application target is the high-power laser diode array heat sink. However, due to some related technical problems, such as the polishing and metallization of the diamond film and the compatibility with the device semiconductor process, the industrial application has not yet been realized. However, in recent years, China has made great progress in the preparation of large-area high thermal conductivity grade diamond self-supporting membranes, and has the ability to prepare diamond heat of various thermal conductivity grades of 8w/cm·K-19W/cm·k. Sinking. In recent years, the demand for diamond heat sink sheets has been increasing in foreign countries, and China has a very obvious cost advantage in the preparation of diamond heat sink sheets. Whether it is hot wire CVD, hot cathode CVD or high-power DC Arc Plasma Jet CVD, it is possible to supply various specifications of heat sink sheets to foreign markets at a price equivalent to only 1/2-1/3 of foreign countries. Wire CVD and hot cathode CVD can only prepare heat sink sheets of 15 W/cm·K or less, and DC Arc Plasma Jet CVD is required for higher heat conductivity grade heat sink sheets. However, at present, the domestic equipment level is still unable to meet the production requirements of large-volume diamond heat sink sheets, and it is necessary to develop large-area high-quality diamond self-supporting film deposition equipment suitable for industrial mass production. In addition to high-power laser diode arrays, diamond film heat sinks are also used abroad for diamond packaging of MCMs (multi-chip 3D assembly technology) and power semiconductor devices (Power ICs). The extremely high thermal conductivity of the diamond film makes it a very good application prospect in terms of miniaturization and miniaturization of the device. For foreign countries, the main technical obstacles at present are the cost of preparation and processing of diamond films. If the domestic ability to provide various thermal conductivity grades of cheap diamond film heat sink wafers to foreign markets in the last 2 to 3 years, It is possible to quickly enter the international market and maintain strong competitiveness.
Domestic research on diamond film active electronic devices, diamond film detectors and sensors, and electrochemical applications of diamond films has not made much progress. However, in recent years, research on cold cathode field emission and vacuum microelectronic devices, surface acoustic wave devices (SAW) and the like has been quite active. However, there is no small gap compared with foreign countries, especially in device development and practical application research and development.
Nano-diamond film is a new hot spot in the research field of CVD diamond film which has appeared in recent years. Compared to a conventional diamond film (also referred to as a microcrystalline diamond film having a grain size of from 0.3 μm to several hundreds μm), the nanodiamond film has a grain size of only 0.2 μm to several nm. Therefore, the surface of the nano-diamond film is extremely smooth and flat, the surface roughness can be below Ra 20nm, and the friction coefficient is only 0.06-0.1, which is lower than the usual micro-diamond film (about 0.1). The grain boundary of the nano-diamond film is composed of sp2 hybridized carbon atoms. The electrical properties of the nano-diamond film are quite different from those of the micro-diamond film in the presence of a large number of grain boundaries. The resistivity of the nano-diamond film and the boron-doped micro-diamond film Quite, and it has extremely excellent cold cathode field emission properties and electrochemical properties. Nano-diamond films may have advantages over ordinary micro-diamond films in many high-tech fields such as diamond coating tools, friction and wear, field emission, MEMS (micro-electromechanical systems), important infrared optical material protective coatings and electrochemistry. At present, many units in China are already carrying out relevant research and development work, and have made gratifying research progress.
3 Suggestions on the industrialization of CVD diamond film in China;
Based on the above-mentioned situation and the characteristics of China's (especially Beijing) technical and economic development and the existing research and development basis, it is recommended that:
(1) In order to adapt to the rapid development of the automotive industry, electromechanical and defense industries in Beijing, it is recommended to support the industrialization of diamond film coated cemented carbide tools. The focus should be on:
1 diamond film coated cemented carbide tool industrial coating equipment (single equipment annual production capacity: diamond coated carbide inserts or drill bits more than 100,000) and supporting industrial production technology research and development;
2 Diamond film coated cemented carbide tool quality monitoring and control technology research and development; 3 key product development and industrial production technology research and development:
A. Precision cutting tools for high-efficiency precision machining of high-silicon aluminum alloys and various difficult-to-machine materials (composites, ceramics, polymer materials) for the automotive industry and the defense industry;
B. Diamond film coated carbide micro drills for integrated circuit board processing (drilling) and industrial production technology development;
C. Diamond film coating woodworking tools and industrial production technology research and development. (2) In order to adapt to the rapid development of microelectronics and optoelectronic technology in China and Beijing, and the trend of miniaturization of devices, it is recommended that: 1 R & D can be used for large-area (F100mm or more) optical grade, heat sink grade and tool grade diamond self-supporting film batch Production of industrialized diamond film deposition equipment (single equipment annual production of diamond white film (tool-level) capacity of about 30,000 carats) and the corresponding production technology, as soon as possible (competing in about 2 years) to establish the first to provide the above products to foreign markets in bulk Industrialized production capacity; 2 research on MCMs technology and power semiconductors (Power ICs) diamond packaging technology using high thermal conductivity diamond substrates, promoting the miniaturization and upgrading of microelectronics and optoelectronic devices, and forming market applications; 3 using diamond film substrates Research on surface acoustic wave devices to develop a new generation of high-performance mobile communication technologies.
(3) Research and develop high-power industrial CO2 laser window products and industrial production technology, provide cheap optical grade diamond white support film window to domestic and foreign markets, and promote technological progress in domestic laser processing industry;
(4) Conduct research on preparation, characterization and application development of nano-diamond films, and encourage the application of nano-diamond films in high-tech fields such as tools, friction and wear, MEMS, field emission flat panel display and optical coating.
4 Conclusion In the past ten years, CVD diamond film technology research has made tremendous progress, and has begun to enter the industrial application stage in some application fields such as tools, thermals and optics. At home and abroad, some emerging diamond film industries have emerged.
According to the domestic technology development status and the domestic (Beijing area) technical and economic development characteristics, in addition to the existing diamond self-supporting film tools (and friction and wear) applications, diamond film coating tools and diamond heat sink substrates are likely to be in the near future. Industrialization is achieved and the market prospects are better. Optical grade diamond self-supporting film industrial CO2 laser window, diamond package with high thermal conductivity diamond substrate MCMs and power semiconductors (Power ICs), field emission display device and surface acoustic wave device (SAW) and nanodiamond film applications Will enter the market one after another. The industrialization of diamond film will not only produce huge market economic benefits, but also may have a profound impact on the development of many high-tech fields in China and Beijing and the technological progress of related industries. In addition to the unremitting efforts of the relevant government departments and the unremitting efforts of the vast number of scientific and technological personnel, the realization of the above project objectives requires the active participation of people of insight in the business community. The progress made in the field of CVD diamond film research in recent years is indeed undoubted. Compared with the past few years, the current technology is closer to the market application, and although there are still some risks, it has reached a level that can be predicted and tolerated. Because the application of diamond film is very broad, the risk in the field of diamond film industrialization will not be catastrophic. For those who want to get involved in industrial development in this field, the key is to have a good quality. R&D team and a strong R&D base (center). Therefore, in the future construction of the diamond film emerging industry, the model of “production, learning and research†is still the best choice.
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