National Standards for Hydrogen Purity Grades
Hydrogen purity grades are defined under national standard systems. In China, hydrogen purity is mainly classified into several levels according to its intended application, particularly for industrial and electronic uses.
What Is the Standard for 99.999% High-Purity Hydrogen?
The standard for 99.999% (5N) high-purity hydrogen specifies strict limits on impurities. Typical requirements based on mass fraction and content control include:
- Nitrogen (N₂): ≤ 3 ppm
- Methane (CH₄): ≤ 1 ppm
- Acetylene (C₂H₂): ≤ 0.5 ppm
- Total hydrocarbons: ≤ 1 ppm
- Carbon monoxide (CO): ≤ 1 ppm
- Carbon dioxide (CO₂): ≤ 2 ppm
- Oxygen-containing carbon compounds: ≤ 1 ppm
- Oxygen (O₂): ≤ 1 ppm
- Volatile organic compounds (VOCs): < 0.1 ppm
- Organic contaminants (olefin-type compounds): ≤ 1 ppb
- Polyhydrocarbons: ≤ 10 ppb
- Other trace impurities (including oxygenated aldehydes and nitrates): ≤ 10 ppb
- Moisture (H₂O): ≤ 20 ppm
These specifications ensure that hydrogen meets the stringent requirements of high-end industrial and electronic manufacturing processes.
Hydrogen Purity Grades and Typical Applications in the Electronics Industry
| Hydrogen Grade | Purity Level | Key Impurity Limits (Typical) | Main Applications in the Electronics Industry |
|---|---|---|---|
| Industrial Hydrogen | ≥99.9% | Basic control of N₂, O₂, moisture | General industrial processes, non-critical chemical reactions |
| High-Purity Hydrogen (5N) | 99.999% | N₂ ≤ 3 ppm; CH₄ ≤ 1 ppm; C₂H₂ ≤ 0.5 ppm; CO ≤ 1 ppm; CO₂ ≤ 2 ppm; O₂ ≤ 1 ppm; Total hydrocarbons ≤ 1 ppm; H₂O ≤ 20 ppm | Semiconductor wafer growth, annealing processes, CVD carrier gas, TFT panel manufacturing |
| Ultra-High-Purity Hydrogen (6N) | 99.9999% | Impurities controlled at sub-ppm to ppb levels; extremely low moisture and oxygen | Advanced semiconductor nodes, high-precision lithography, critical etching and deposition processes |
| Electronic-Grade Hydrogen | ≥5N–6N | Strict control of moisture, oxygen, CO, metal ions, and organic contaminants | Semiconductor manufacturing, optical fiber production, LCD and OLED panel fabrication |
| Reducing-Grade Hydrogen | ≥99.99% | Low oxygen and moisture content | Reduction of metal oxides (tungsten, molybdenum), electronic material powder preparation |
Hydrogen Purity Requirements and Safety Standards in the Electronics Industry
Hydrogen used in the electronics industry typically requires extremely high purity levels, generally 99.999% (5N) or higher, and in many advanced applications 99.9999% (6N) ultra-high-purity hydrogen is required. Even trace amounts of impurities—especially moisture, oxygen, carbon monoxide, and metal ions—can cause severe degradation in product yield and device performance.
Therefore, relevant technical standards impose very strict impurity limits. During use, hydrogen handling must strictly comply with safety and technical regulations, including the installation of hydrogen leak detection systems, flashback arrestors, and ensuring adequate ventilation in the workplace to minimize explosion risks.
Role of Electronic-Grade Hydrogen in High-Tech Industries
Electronic-grade hydrogen is a form of high-purity hydrogen that plays a critical role in high-technology industries, particularly in semiconductor manufacturing and new energy applications. Its use is deeply integrated into the production processes of advanced electronic components such as semiconductors, optical fibers, and display panels, all of which demand exceptionally stringent gas purity levels.
1. Semiconductor Manufacturing
In semiconductor fabrication, hydrogen is primarily used as a protective gas, reducing gas, and carrier gas, all of which are essential for maintaining a clean process environment and controlling chemical reactions.
- Wafer Growth and Thermal Processing:
During single-crystal silicon growth and epitaxial processes, high-purity hydrogen is used as a protective atmosphere to prevent silicon oxidation at high temperatures. In annealing processes, hydrogen helps repair lattice defects, improving wafer quality and electrical performance. - Chemical Vapor Deposition (CVD):
In CVD processes, hydrogen is commonly used as a carrier gas to transport reaction precursors into the reaction chamber and participate in reactions that form high-quality thin films. - Etching and Cleaning:
Hydrogen can be mixed with other gases, such as hydrogen fluoride, for precise wafer etching or for removing trace oxides and contaminants from wafer surfaces. These processes are essential for manufacturing highly integrated semiconductor devices.
2. Optical Fiber Manufacturing
In optical fiber production, particularly during the preparation of preforms, hydrogen–oxygen flames are used for high-temperature heating in the range of 1200–1500 °C. Such flames require hydrogen with extremely high purity. The presence of solid particles or impurities can create black spots on the preform surface, significantly degrading optical transmission performance.
3. Display Panel Manufacturing
Hydrogen is also indispensable in the production of liquid crystal displays (LCDs) and emerging OLED panels. It is mainly used to create ultra-clean, oxygen-free, and moisture-free environments, serving as a protective gas to ensure that critical structures such as thin-film transistor (TFT) arrays are not contaminated during deposition and annealing processes.
4. Preparation of Electronic Materials
Many metal materials used in the electronics industry rely on the strong reducing properties of hydrogen. For example, in the production of refractory metals such as tungsten and molybdenum, high-purity hydrogen is used to reduce metal oxides, producing metal powders with finer particle sizes and higher purity. These powders serve as essential base materials for manufacturing electronic components.
About Jinhong Gas
Jinhong Gas is a professional supplier of industrial and electronic specialty gases, offering high-purity and ultra-high-purity hydrogen solutions for the electronics, semiconductor, and advanced manufacturing industries. With strong capabilities in gas purification, quality control, and supply chain management, Jinhong Gas provides stable hydrogen products ranging from 5N to 6N purity levels. We are committed to supporting customers with reliable, safe, and consistent gas supply solutions that meet the most demanding technical and regulatory requirements of modern electronic manufacturing.
