Compressed air cleanliness of semiconductor plant

In semiconductor manufacturing, the cleanliness of compressed air directly determines the yield and product reliability of chip production, and its core requirements can be summarized as follows, and combined with the technical characteristics of water lubricated air compressor to explain:

1. cleanliness core requirements

1. particulate matter control
   semiconductor processes are extremely sensitive to micron and even submicron particles. For example, in a 3 nanometer process, 0.01 micron dust particles can cause transistors to short. Therefore, the concentration of particles in compressed air needs to be strictly limited, usually requiring no more than 10,000 particles larger than 0.1 microns per cubic meter of air (some high-precision processes require less).

2. No oil pollution
   the oil will be adsorbed on the wafer surface, affecting the electrical properties of the chip and even corroding the equipment. The semiconductor industry requires compressed air to be completely oil-free, and the total oil content needs to be controlled at a very low level (usually less than 0.01 mg/m3), and some processes even require "zero oil" standards.

3. Low moisture content
   moisture may cause equipment rust, photoresist degradation, or material oxidation. The dew point temperature of compressed air usually needs to be controlled below -40 ℃, and some scenes require below -70 ℃ to ensure that the water content is extremely low.

Technical Adaptability of 2. Water Lubricated Air Compressor

1. core advantages of oil-free compression
   water-lubricated air compressor replaces traditional lubricating oil with pure water to form a dynamic water film in the compression chamber to achieve oil-free lubrication. This technology avoids the risk of oil pollution from the source, and the cleanliness of the compressed air can meet the stringent requirements of the semiconductor industry for "zero oil.

2. Auxiliary effect of particulate matter control
   the closed cycle design of the water lubrication system reduces the particles generated by mechanical friction, and the water film can absorb some impurities, further reducing the particle concentration in the compressed air. With multi-stage filtration system (such as precision filter, activated carbon filter), can ensure that the particle concentration meets the semiconductor process standards.

3. Solutions for moisture management
   the compressed air discharged from the water-lubricated air compressor contains trace amounts of water vapor, and the dew point temperature needs to be reduced to below -40°C through a deep drying system (such as an adsorption dryer) to meet the requirements of the semiconductor industry for low moisture content.

3. Technology Comparison and Selection Suggestions

1. contrast with oil air compressor
   even if the traditional oil air compressor is equipped with an oil separator, it is difficult to stably meet the requirements of the semiconductor industry for oil content (below 0.01 mg/m3). The water-lubricated air compressor achieves oil-free compression through physical isolation (water film), which solves the problem of oil pollution from the root.

2. Comparison with dry oil-free air compressor
   dry oil-free air compressors achieve oil-free compression through special coatings or materials, but the coating life is limited and needs to be returned to the factory regularly for repair. The water lubricated air compressor uses water as the lubricating medium, the operating temperature is low (40-60 ℃), the maintenance is simple, and the winter antifreeze demand can be solved through the system design (such as electric heat tracing insulation).

3. Select Recommendations

   • scenes with low tolerance for water content: The water-lubricated air compressor is preferred, and the cost and performance can be balanced with the deep drying system.
   • Scenarios requiring high antifreeze conditions: The workshop environment needs to be evaluated. If the temperature is too low in winter, water lubrication type with antifreeze design or dry oil-free air compressor can be selected.
   • Long-term cost considerations water lubricated air compressor maintenance is simple (no need to replace the oil, oil filter), long-term operation cost is lower.

Key Points of 4. System Matching and Operation and Maintenance

1. multistage Filtration and Drying
   water lubricated air compressors need to be equipped with precision filters (0.01 microns) and adsorption dryers to ensure that the compressed air's particulate, oil and moisture content meet the standards.

2. Real-time monitoring and alarm
   install dew point sensor, oil vapor detector and other equipment, real-time feedback of compressed air quality parameters, abnormal situation automatic alarm, to avoid process pollution.

3. Pipe material and installation
   using electrolytically polished stainless steel pipes (surface roughness ≤ 0.4 microns), welded connections reduce the risk of leakage and ensure that the compressed air is not polluted twice during transportation.