Tungsten hexafluoride
2025/8/1
The technical indicators of electronic grade tungsten hexafluoride (WF₆) are strictly classified according to application scenarios (such as semiconductor deposition, advanced processes). The core standards are as follows:
1. Purity level and applicable scenarios
|
grade |
Purity requirements (volume fraction) |
Applicable scenarios |
|
Basic electronic grade |
≥99.995%(≥4N5) |
Photovoltaic cells, LCD panels, semiconductor deposition technology above 28nm |
|
Super high-purity |
≥99.999%(≥5N) |
Advanced manufacturing processes below 14nm, 3DNAND memory chip manufacturing |
|
Cutting-edge |
≥99.9999%(≥6N) |
3nm/5nm extreme ultraviolet lithography (EUV), high-end interconnect layer deposition |
Market share: Level 5N accounts for 92.8% of global production capacity, and level 6N accounts for only 8% due to process difficulty.
2. Key impurity limits (taking level 5N as an example)
|
Impurity type |
Limit requirements |
The consequences of exceeding the standard |
|
Oxygen (O₂)+Nitrogen (N₂) |
≤10ppm |
The wafer surface oxidizes, and the film adhesion decreases |
|
Moisture (H₂O) |
≤5ppm (dew point ≤-60℃) |
Hydrolysis produces HF, corroding the deposition cavity |
|
Hydrogen fluoride (HF) |
≤20ppm |
Damage the silicon lattice structure and reduce device yield |
|
Total metal ions |
≤11pb（Fe/N/Whereflow |
Induces a circuit short circuit and increases leakage current |
|
Carbon tetrafluoride (CF₄) |
≤0.5ppm |
Reduce the CVD deposition rate |
|
Particulate matter (≥0.1μm) |
≤100 pieces/L |
Causes chip surface defects |
6N level special requirements:
PH₃/AsH₃ ≤0.05 ppb
Total hydrocarbon impurities ≤0.1 ppm
3. Packaging and storage and transportation specifications
Container requirements
316L stainless steel cylinder, electrolytic polishing and passivation treatment of inner wall.
The valve is made of nickel-based alloy and is equipped with a double blocking and leakage prevention device.
Filling standards
Filling pressure ≤0.09 MPa (40L cylinder charging capacity ≤50kg)
Filling coefficient ≤1.33 kg/L (refer to the analogy of sulfur hexafluoride)
Storage and transportation conditions
The storage temperature away from light is ≤25℃, and the humidity is ≤45%.
Shock prevention is required during transportation (bumping frequency ≤2.5 times/second).
UN number 2196, leakage concentration alarm threshold 0.5%.
4. Testing methods and standard basis
|
Testing items |
method |
Standard basis |
|
Purity and gas impurities |
Gas chromatography-mass spectrometry combined (GC-MS) |
GB/T 32386-2025 |
|
moisture |
Karl Fischer Coulomb method (accuracy ±0.1ppm) |
GB/T 5832.3 |
|
Metal ions |
ICP-MS (detection limit 0.1ppb) |
Semi c10 |
|
Particulate matter |
Laser dust particle counter (0.1–10μm) |
ISO1 4644-1 |
|
HF residue |
Ion chromatography (detection limit 0.03mg/L) |
GB/T 31995 |
Mandatory enforcement standards:
Purity and safety: GB/T 32386-2025 (replace 2015 version)
Environmental protection label: GB 13690-2009 "Public announcement of chemical hazards"
5. Apply risk control
CVD deposition process:
O₂ >10 ppm causes the resistivity of tungsten film to increase by 30%, and HF >20 ppm corrodes the vacuum pump oil.
3nm EUV lithography:
Metal ions >1 ppb cause line width deviation ≥5%, and particulate matter exceeds the standard and leads to mask contamination.
Leakage emergency:
Nonute with sodium carbonate immediately when exposed to water, and operators must wear fluoroelastic protective equipment.
A wafer factory failed to deposition of the entire batch of chips due to moisture exceeding the standard (8 ppm), and lost more than ten million US dollars.
Anhui Shunyuxin Chemical Technology Co.,Ltd. Copyright disclaimer