With a domestic production rate of only 20%, is China’s strategic gas supply also “choked”? An academician explains how we can break free from this predicament.

When it comes to gases, most people first think of air and oxygen—gases that are readily available and inexpensive. However, some gases are incredibly valuable, and every year we even spend enormous sums of money importing them from abroad. These are industrial gases, including krypton and argon. They are essential raw materials without which modern industry simply cannot function. They are widely used in critical sectors such as steel, metallurgy, petroleum, chemical engineering, electronics, and healthcare, playing a powerful strategic role—and are even referred to as the “blood of industry.” For a long time, China has been heavily reliant on Germany, the United States, and France for its industrial gases. Among the specialty gases required for the production of integrated circuits, the domestic self-sufficiency rate stands at only 20%. Faced with this “anemia” in our industrial bloodstream, how can we break free from this predicament?

“The lifeblood of industry”

　　Industrial gases refer to gases used in industrial production, serving as raw materials, fuels, protective atmospheres, transport media, driving gases, and heat-transfer agents. In high-tech and advanced industries, oxygen and hydrogen can be used as rocket fuels; helium acts as a superconducting coolant in hospital MRI scanners; and neon is the working gas for light sources in chip lithography machines. The variety of industrial gases is extremely rich—there are hundreds of types—and they can be broadly categorized into two main groups: bulk gases and specialty gases. Bulk gases are those used in large quantities and with wide-ranging applications—for example, oxygen, nitrogen, and argon separated from air, as well as chemically synthesized gases such as ammonia, ethylene, propylene, and acetylene. Specialty gases, on the other hand, are gases applied in specific fields that have particularly stringent requirements for purity, quality, and performance—for instance, various high-purity gases used in chip manufacturing, as well as special gases employed in defense, medical care, food processing, and other sectors. As we can see, industrial gases permeate every stage of industrial production and play an irreplaceable role, which is why they are often referred to as "the lifeblood of industry." Just how critical are industrial gases? Take the semiconductor industry as an example: the fabrication of chips relies on lithography machines. Lithography involves using lasers of specific wavelengths to induce chemical reactions in photoresist materials. Through exposure and development, patterns designed on photomasks are transferred onto silicon wafers. The specific wavelengths required are generated by excimer lasers in commonly used deep-ultraviolet (DUV) lithography machines, and these lasers are filled with 97% neon gas.

　　Seventy percent of the world’s neon gas is supplied by Ukraine. However, the Ukraine crisis has led to a halt in neon production, causing supply shortages and a sharp surge in prices. Although neon does exist in the atmosphere, it accounts for only 0.0018% of air; its production relies entirely on air separation technology.

　　Large-scale air separation units are of paramount importance.

　　Air separation, often referred to as "air separation," is a chemical separation technology that uses various techniques to isolate the individual components of air and obtain different gaseous products. Initially, the primary purpose of air separation technology was not to produce neon gas, but rather to manufacture oxygen and nitrogen—gases widely used in industrial applications. In 1903, Germany's Linde designed and built the world's first industrial oxygen generator with a capacity of 10 cubic meters per hour; more than a century has passed since then. For a long time, the global air separation market has been dominated by four major gas companies from Germany, France, and the United States.

　　The principle of air separation is not complicated; the real challenge lies in the equipment used for air separation, especially large- and ultra-large-scale air separation units. The manufacturing capability of large air separation plants serves as an important indicator of a country's technological level in air separation. China's air separation industry got its start in the 1950s. After going through stages of exploration, cooperation, and independent R&D, it wasn't until around the year 2000—thanks to the rapid development of industries such as steel and coal chemical engineering—that China's large- and ultra-large-scale air separation technologies and equipment achieved a qualitative leap.

　　For a long time, large-scale air separation equipment has been virtually monopolized by foreign companies. In recent years, thanks to the rapid development of coal-to-chemicals industries, China’s air separation equipment sector has finally turned a corner. The 100,000-level (100,000 cubic meters per hour) air separation unit developed by China represents a milestone achievement in the localization of critical technological equipment. Air separation equipment manufactured domestically not only boasts excellent oxygen purity but also features low energy consumption, lower production costs, and superior performance. In particular, its long-term stable operation significantly outperforms that of foreign counterparts, making it one of our “national strategic assets.” The advancement of large-scale air separation technology has also paved the way for China’s independent production of neon gas, while simultaneously enabling the co-extraction of several other rare gases—including krypton and xenon, which are as valuable as gold. Currently, China accounts for 40% of the global neon market share, surpassing Ukraine and providing strong assurance for the healthy development of China’s related industries.

　　Semiconductor production requires hundreds of types of gases.

　　Specialty electronic gases used in the industrial gas sector—including xenon, krypton, and fluorine-containing gases—are critical materials indispensable to the manufacturing processes of integrated circuits, semiconductor displays, and semiconductor devices. Producing a single chip requires more than 100 different types of specialty electronic gases; however, China can currently only produce about 20% of these varieties, leaving the rest dependent on imports. For some of these gases, the price can soar to tens of thousands of yuan per kilogram. The chip manufacturing process is highly complex, involving nearly every stage—from polysilicon production through polishing, epitaxy, diffusion, film deposition, sputtering, etching, doping, electroplating, cleaning, and final packaging—all of which almost invariably rely on the use of specialty electronic gases. Specialty electronic gases rank as the second-largest consumable material in chip manufacturing.

　　According to the specific process stage, electronic specialty gases can be categorized into epitaxy gases, deposition gases, etching gases, doping gases, and more. Each category encompasses numerous subtypes. Deposition gases are primarily composed of silicon-containing gases such as silane; after silane decomposes, it forms the desired thin film on the wafer surface. Etching gases commonly include fluorine-containing compounds like carbon tetrafluoride and octafluorocyclobutane. Their function is to etch patterned silicon wafers, creating grooves with specific structures. Doping gases are gases containing elements such as arsenic, boron, and phosphorus, which are used to introduce these elements into silicon wafers, thereby forming semiconductor devices. How do these gases work during the etching process? Currently, the mainstream etching method is dry etching, which includes both chemical etching and physical etching. Chemical etching employs fluorine-containing gases; its basic principle involves using a plasma-generation device to ionize these fluorine-containing gases into free fluorine radicals. These fluorine radicals then combine with silicon to form gaseous silicon tetrafluoride, which can be easily pumped away without leaving any residue. In this way, precise grooves with specific structures can be etched onto the silicon wafer.

　　The technological barriers to the production of electronic specialty gases are extremely high.

　　The “special” aspect of specialty electronic gases lies in their exceptionally high purity requirements. Purity refers to the higher the content of the main component, the better; cleanliness refers to the lower the residual amount of impurities, the better. For a 90-nanometer process, the required purity level is between 5 and 6 Ns, where "N" represents the number of nines in the purity percentage. At the same time, impurity levels must be below 10 to the power of negative 9—that is, one part per billion. For 28-nanometer, and even 7-nanometer and 5-nanometer processes, the purity requirements for specialty electronic gases are even more stringent: metallic elements must be purified to one part per trillion—equivalent to the amount of impurities in 20 standard swimming pools not exceeding the volume of a single drop of water. Why such stringent purity standards? Because even trace amounts of impurities can cause significant defects in products. For example, impurities such as moisture and oxygen can lead to oxidation of metals and the formation of particulate matter, causing short circuits and damage to circuitry. As the process technology advances from 28 nanometers to 7 nanometers, the metal impurity levels in products must decrease by a factor of 100, and the size of contaminant particles must shrink to less than one-fourth of their original dimensions. As the manufacturing process continues to evolve beyond 10 nanometers, the demands on impurity filtration and cleanliness during production will only become increasingly stringent.

　　Such stringent requirements have made the technological barriers to producing electronic specialty gases extremely high, demanding long-term accumulation and substantial R&D investment. Moreover, the production process involves a large number of sophisticated instruments and equipment, presenting the first major hurdle. The second challenge lies in regulatory barriers: since the quality of electronic specialty gases significantly affects the performance of electrical products, any quality issues could result in enormous losses for downstream customers. To ensure a stable supply of gases, customers, once they establish cooperative relationships with gas suppliers, are unlikely to switch suppliers easily. Therefore, if a new entrant wishes to gain access to this market, it must undergo rigorous scrutiny and certification—a process that typically takes two to three years. Given that developed countries started their electronic information industries earlier and enjoy advantages in technology, capital, and talent, China has long been dependent on imports. More than 85% of the market share is monopolized by companies from the U.S., France, Germany, Japan, and other nations—especially ultra-high-purity specialty gases, which are almost entirely reliant on imports. Whether or not these gases are sold, and at what volume, is entirely up to them. Thus, China must as soon as possible develop domestically produced technologies for key electronic specialty gases to eliminate the risk of being “choked” and firmly secure the lifeline of our national economy in our own hands. From a technical standpoint, China’s electronic gas industry needs to achieve breakthroughs in the following areas: First, purification materials—the core materials used in gas-end purifiers, such as catalysts, adsorbents, and membrane materials for purification; second, new products and technologies—given the rapid pace of innovation in electronic specialty gases, domestic R&D and blending technologies lag behind those overseas. For instance, some domestic electronic specialty gases like nitrogen trifluoride and sulfur hexafluoride have already been phased out internationally; third, equipment—equipment that comes into contact with high-purity gases must meet stringent cleanliness standards; otherwise, even trace impurities released could contaminate the electronic gases. Currently, many containers, pipelines, and valves used in production still need to be imported, making it imperative that we accelerate R&D efforts in this area; fourth, testing technologies—analytical testing is crucial for ensuring product quality. While some purity-indicator testing technologies already have a solid foundation, there remains a significant gap compared to foreign counterparts in high-precision analysis and detection of ultra-trace impurities, as well as in specialized instrumentation. In recent years, several Chinese enterprises, after years of independent R&D, have managed to bring certain electronic specialty gas products into mass production and have obtained certifications from leading international companies. In the future, more such products will gradually enter the global semiconductor supply chain system.