The compressed air in the lithography machine is mainly used to drive precision pneumatic components, maintain equipment stability, ensure a clean environment and participate in temperature regulation, which is the key factor to ensure the accuracy of nano-scale operation and process stability. The specific role is as follows:
drive precision pneumatic components
- wafer table suspension air cushion: The wafer table in the lithography machine needs to achieve 0.1 micron precision suspension positioning, which relies on air bearing technology. The compressed air passes through the air bearing to form an extremely thin gas film, which completely isolates the wafer table from the mechanical structure and avoids friction and vibration caused by direct contact. This non-contact suspension method ensures the absolute stability of the wafer during the exposure process, and provides the basis for the lithography operation of nanoscale precision.
- Lens temperature adjusting device the optical system of the lithography machine is extremely sensitive to temperature changes, and the temperature difference needs to be controlled within 0.01°C. The compressed air maintains the constant temperature of the lens through a constant flow of air, preventing thermal deformation of the optical components due to temperature fluctuations, thus ensuring the accuracy of the exposure system.
- Mechanical arm positioning mechanism the automated robotic arm inside the lithography machine is used for fast grasping, handling and precise positioning of wafers, carriers and other materials. Compressed air is used as the power source to drive the cylinder and pneumatic motor to realize the fast and precise movement of the robot arm, ensuring the accurate positioning of each component in the nano-scale operation.
Maintain equipment stability
- barometric stability the lithography machine requires extremely high pressure stability of compressed air, generally requiring a pressure between 0.5-0.7MPa, and the fluctuation range needs to be controlled within a very small range. Stable air pressure is very important to maintain the precision of the lithography machine, and the fluctuation of air pressure will affect the performance of components such as air spring vibration isolator, resulting in slight displacement or vibration of the optical system of the lithography machine, thus affecting the exposure accuracy.
- Flow stability different parts of the lithography machine have different flow requirements for compressed air at different working stages. Ensure that the compressed air flow is stable, can meet the gas demand of each component of the lithography machine, and ensure the continuity and stability of the lithography process.
Ensure a clean environment
- cleaning guarantee the compressed air after three-stage filtration forms a protective air curtain inside the lithography machine to isolate dust and other pollutants. In the wafer manufacturing process, the surface is easy to adsorb small particles and impurities, the use of clean compressed air for purging and cleaning, can effectively remove the wafer surface impurities, while avoiding damage to the wafer due to excessive air flow, to ensure the cleanliness of the wafer and product quality.
Participation in temperature regulation
- lens temperature control: As mentioned earlier, compressed air maintains the constant temperature of the lens through a constant airflow, preventing thermal deformation of the optical components due to temperature fluctuations. This is very important to ensure the accuracy of the exposure system, because the small deformation of the optical element will directly affect the transfer accuracy of the lithography pattern.
