How to choose an industrial oil-free air compressor for semiconductor etching
Semiconductor etching industry background
In the semiconductor wafer etching process, compressed air is widely used in the following aspects:
- Drive vacuum chuck;
- Control reaction chamber pressure;
- Cleaning photoresist residue。
Due to the high precision requirements of semiconductor processes, compressed air must meet very high cleanliness standards to avoid contaminating the wafer surface. Requirements that need to be met include:
- ISO 8573-1 Class 0(Oil content ≤0.01mg/m³) to prevent lubricating oil volatilization and pollution;
- SEMI F5(Guidelines for Clean Compressed Air), requiring particle size ≤0.01μm (in compliance with ISO 14644-1 Class 1 standard);
- IEC 61340-5-1(Electrostatic protection standard), compressed air needs to pass through antistatic treatment with a conductivity of ≥1μS/cm.
According to the SEMI 2023 industry report, oil-containing compressed air may increase the wafer scrapping rate by 0.3%-0.8%, and the single pollution loss can be as high as US$500,000.
Why semiconductor etching requires industrial oil-free air compressors
- Absolute cleanliness guarantee: Oil-free technology eliminates 0.1-0.5μm carbide particles produced by cracking of lubricating oils, avoiding violations of SEMI E78 cleanliness specifications, thereby preventing short circuiting wafer lines.
- static control: The water-based lubrication system has its own conductivity (resistivity ≤10 Ω·cm, certified by ANSI/ESD S20.20), which can prevent electrostatic discharge (ESD) from damaging nanoscale transistors.
- process stability: Pressure fluctuations are maintained at ≤±0.2%(in compliance with SEMI E109 dynamic pressure control standard) to ensure uniformity of etching rate, with an error of less than 0.5%.
Selection of core parameters for semiconductor etching (with international standards)
- cleanliness control：
- oil content: ≤0.001mg/m³ (stricter than ISO 8573-1 Class 0);
- particulate matter: ≤0.003μm (passed ISO 29463 high-efficiency filter test);
- anti-static performance：
- air conductivity: 1-10μS/cm (compliant with SEMI F47 fab electrostatic protection standard);
- surface resistance: ≤10 Ω (passed ASTM D257 material conductivity test);
- supply stability：
- pressure fluctuations: ≤±0.15%(meets ISO 1217 Annex D dynamic pressure test);
- Instantaneous flow response time: ≤0.1 seconds (passed the VDMA 15392 industrial compressed air performance certification).
Potential risks of semiconductor etching without using industrial oil-free air compressors
- Product scrapping risk: Lubricating oil vapor deposition on the wafer surface may cause an etching line width error of ≥5nm, exceeding the upper tolerance limit of the SEMI M82 process, thus increasing the risk of scrapping.
- Equipment maintenance costs surge: Oil-containing systems require cleaning of the reaction chamber every month (costing approximately $12,000 per time), and the life of the vacuum pump is reduced by 40%(violating the SEMI S2 equipment reliability specification).
- Compliance penalties: If you fail to pass the cleanliness requirements of the ITRS 2.0 technology roadmap, you may face the risk of wafer foundry qualification being revoked.
Economic benefits of using industrial oil-free air compressors
| project | Industrial oil-free air compressor | oil-lubricated air compressor |
|---|---|---|
| initial investment | $350,000 | $250,000 |
| Total cost for 3 years (including operation and maintenance) | ≤$420,000 | ≥$600,000 |
| Wafer scrapping costs | 0 | ≥ $1.5 million/quarter |
| Cost of carbon emissions (year) | $0 (compliant with ISO 14064) | ≥$25,000 (carbon tax + waste oil treatment) |
Comparison of the application of industrial oil-free air compressor and oily air compressor in semiconductor etching
| indicators | Industrial oil-free air compressor | oil-lubricated air compressor |
|---|---|---|
| cleanliness level | ISO 8573-1 Class 0 | ISO 8573-1 Class 1 |
| Static control capabilities | Comply with SEMI F47 | Additional ionization device is required |
| Maintenance labor costs | 0.2 person/year | 1.8 person/year |
| process stability | Good product rate ≥99.98% | Yield ≤99.5% |
summary
With zero oil pollution, nanoscale cleanliness and fully automatic anti-static control, industrial oil-free air compressors have become key equipment for semiconductor etching processes to ensure yield and equipment life. Shanghai Granklin’s industrial oil-free compression technology complies with ISO 8573-1 Class 0 and SEMI F5 standards, providing global semiconductor companies with compressed air solutions that meet the needs of 3nm process.
