What are the compressed air indicators for the semiconductor industry

In the semiconductor industry, the indicators of compressed air (CDA, clean and dry air) need to meet the requirements of extremely high purity, stability and specific processes. The following are the key indicators and analysis:

1. core cleanliness indicators

1. particulate matter control
   • standard requirements: The content of micron (even sub-micron) particles in compressed air should be strictly limited. For example, critical equipment such as lithography machines require compressed air to achieve ISO 14644-1 cleanliness level 5 or better, I .e., no more than 10,000 particles equal to or greater than 0.1 microns per cubic meter of air.
   • Impact: Particulate matter may scratch the wafer surface or contaminate optical components, resulting in short circuits or performance defects. For example, in the 3nm process, a 0.01 micron dust can connect the transistor, causing product failure.
2. No oil pollution
   • standard requirements the semiconductor process is highly sensitive to oil and requires compressed air to be completely oil-free (the total oil content is usually less than 0.01ppm, even up to 0.00ppm).
   • Impact: Oil will be adsorbed on the wafer surface, affecting chip performance and yield, and may corrode equipment. For example, traditional oil-containing air compressors are prone to problems such as coating shedding and equipment blockage.
3. Low moisture content
   • standard requirements: The dew point is controlled at a very low level through the drying device (usually the pressure dew point is required to be ≤-40 ℃, and some scenes even require ≤-70 ℃).
   • Impact: Moisture may cause oxidation of materials, degradation of process accuracy, or corrosion of equipment. For example, photoresist performance may be affected by water vapor condensation, reducing lithography accuracy.

2. pressure and stability indicators

1. pressure range
   • standard requirements: The working pressure of compressed air pipelines is usually between 0.6-1.0MPa, depending on equipment requirements. For example, the design pressure of most semiconductor chip manufacturing plants is 0.8MPa, and the lithography machine may require the pressure to be stable at 0.5-0.7MPa (or a specific value such as 35PSI, about 0.24MPa).
   • Impact: Pressure fluctuations can affect the normal operation of pneumatic components and components, such as inaccurate movement of the exposure head.
2. Airflow stability
   • standard requirements: It is necessary to ensure that the compressed air flow is stable to meet the gas demand of different components in different working stages.
   • Impact: Airflow fluctuations may cause equipment vibration and displacement, affecting process accuracy. For example, the fluctuation of gas flow during the lithography process may cause slight displacement of the optical element and reduce the lithography pattern accuracy.

3. indicators of microbial and chemical pollutants

1. microbial control
   • standard requirements: The concentration of floating bacteria should be ≤ 5cfu/m & sup3;, and the concentration of settling bacteria should be ≤ 1cfu/dish to prevent microorganisms from breeding in the production environment and contaminating the product.
   • Impact microbial contamination may cause chip surface defects or performance degradation.
2. Chemical Contaminant Limits
   • standard requirements: The content of carbon dioxide, carbon monoxide, total hydrocarbons and other impurities is strictly limited, generally required at the ppb level or even lower.
   • Impact chemical contaminants may corrode equipment or affect chip performance. For example, acidic species may damage the wafer surface, resulting in circuit failure.

4. international and industry standard reference

1. ISO 8573-1
   • content: Compressed air quality standards issued by the International Organization for Standardization (ISO) define the levels and detection methods of pollutants such as particulate matter, humidity, and oil.
   • Application: The semiconductor industry usually adopts the highest level in this standard to ensure the quality of compressed air.
2. SEMI S2/S6
   • content the standards issued by the American Semiconductor Equipment and Materials International Association (SEMI) require semiconductor equipment to meet the requirements of personal safety, environmental protection, and equipment performance.
   • Application: Semiconductor air compressor systems are subject to these standards to ensure equipment safety, stable performance and reliable gas quality.
3. GB/T 2819-2011
   • content compressed air quality standards issued by the National Standardization Administration of China stipulate quality indicators, testing methods and limit values.
   • Application domestic semiconductor companies need to refer to this standard to ensure that the quality of compressed air meets domestic specifications.