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Detailed Explanation of Electronic-Grade Anhydrous Ethanol from UP Grade to UP-S Grade
Electronic anhydrous ethanol, as a high-purity organic solvent, plays an irreplaceable role in the fields of semiconductors, photovoltaics, pharmaceuticals, and precision electronics manufacturing. According to purity grade classification, UP-grade (Ultra Pure) and UP-S-grade (Ultra Pure-Special) correspond respectively to SEMI international standards’ G2 and G3 levels, and their technical specifications differ significantly from those of ordinary industrial ethanol. The following analysis will cover aspects such as technical standards, production processes, application scenarios, and the current market situation.
I. Technical Standards and Grading Criteria
The G2/G3 standards developed by SEMI (the Semiconductor Equipment and Materials International Association) set stringent requirements for metal ion content, particulate matter, and moisture levels.
UP-grade (SEMI G2) Ethanol Requirements: Moisture ≤ 0.1%, Total metallic impurities ≤ 1 ppb (with key elements such as sodium, potassium, and iron each ≤ 0.1 ppb), particulate matter (≥ 0.5 μm) ≤ 25 particles/mL.
The UP-S grade (SEMI G3) further reduces the total metal impurity level to below 0.5 ppb, with a moisture content of no more than 0.05% and particle count controlled to within 10 particles/mL.
Although China’s national standard GB/T 678-2022 specifies requirements for anhydrous ethanol, the highest grade it allows reaches only 99.7% purity, creating a generational gap compared to SEMI standards.
II. Production Process and Key Technologies
1. Molecular sieve adsorption dehydration: Using CG-EA318 or CG-EA319 molecular sieves, 95% industrial ethanol is deeply dehydrated, and combined with multi-stage rectification, the water content is reduced to below 0.1%. If a five-column continuous distillation system is employed, energy consumption can be reduced by 30% compared to conventional processes.
2. Sub-boiling distillation purification: This process involves distillation at a low temperature of 50–60℃ to prevent the carbonization of organic compounds caused by high temperatures. This technique is crucial for controlling particulate matter. Data show that sub-boiling technology can reduce the number of particulate matter by as much as 80%.
3. Terminal Filtration System: Equipped with a 0.1-μm PTFE membrane filter and paired with ultra-clean packaging technology (such as steel cylinders lined with fluororesin), this system ensures that the filling process achieves ISO Class 3 cleanliness. After terminal filtration, particles measuring 0.2 μm can be reduced to fewer than 5/mL.
III. Core Application Scenarios
1. Semiconductor Manufacturing: In the photoresist cleaning stage, UP-S-grade ethanol is used for pre-cleaning in EUV lithography processes. The control of metallic impurities in this step directly affects the yield of processes below 7nm. According to SMIC’s 2024 Technology White Paper, using G3-grade solvents can reduce the wafer surface defect rate to as low as 0.03 defects/cm².
2. Photovoltaic cell production: The back-passivation layer of PERC cells requires UP-grade ethanol for cleaning. If the sodium content exceeds 1 ppb, the conversion efficiency will drop by 0.2%. According to Longi Green Energy’s Q1 2025 report, the company has fully switched to SEMI G2 standard solvents.
3. Biopharmaceutical Field: In the DNA template purification step of mRNA vaccine production, ethanol must be free of RNase. A certain CRO company’s testing revealed that the residual nuclease level in UP-grade ethanol was two orders of magnitude lower than the pharmacopoeial standard.
IV. Market Structure and Progress in Domestic Production
Currently, the global market is dominated by companies such as Germany’s Merck and the U.S.’s Honeywell, whose G3-grade products fetch prices as high as 3,000 yuan per liter. Domestic manufacturers like Jiangsu Qiangsheng Functional Chemistry and Shanghai MacroChem have already achieved mass production of UP-grade products, yet G3-grade products still rely heavily on imports. According to 2024 customs data, China’s imports of electronic-grade ethanol reached 12,000 tons, with G3-grade accounting for 65% of the total. Notably, the “Supercritical CO₂ Extraction and Purification Technology” developed by the 718th Research Institute of China Shipbuilding Industry Corporation has successfully completed pilot testing, achieving metal impurity control down to 0.3 ppb. It is expected that by 2026, this technology will enable domestic substitution for G3-grade ethanol.
V. Quality Control Challenges
1. Trace detection technology: The detection limit of ICP-MS (inductively coupled plasma mass spectrometry) needs to reach 0.01 ppb; some equipment costs over millions of dollars per unit, which restricts small and medium-sized enterprises from entering this field.
2. Storage and Transportation Pollution Risk: Experiments have shown that HDPE containers release zinc at a level of 0.5 ppb after being stored for 30 days. Therefore, high-end products must be packaged in perfluoroalkoxy resin containers.
3. Batch Stability: According to statistics from a photovoltaic company, the potassium ion content in UP-grade ethanol can fluctuate by as much as 0.2 ppb across different batches, necessitating the establishment of an SPC control chart for process monitoring.
With the rapid development of third-generation semiconductors and advanced packaging technologies, demand for UP-S-grade ethanol is expected to grow at an annual average rate of 15%. Future technological breakthroughs will focus on:
1) Molecular sieve purification technology—distillation-coupled process reduces energy consumption;
2) AI-driven purity prediction model;
3) Biodegradable nanomaterial packaging solutions. To break the monopoly in the high-end market, China’s domestic industry needs to achieve coordinated breakthroughs in three areas: standard-setting, testing equipment, and key materials.
Dalian Chuangge Technology Co., Ltd
Richard Han
Doris Zhou
Headquater: 9th Floor, Century Classic Building, No.10, Xinghai Square, Shahekou District, Dalian City, Liaoning Province
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