ASML C2913 Cymer Lens 750A (4022.454.48131)

The ASML C2913, also known as the Cymer Lens 750A with part number 4022.454.48131, is a high-precision optical lens assembly designed for deep ultraviolet (DUV) lithography systems. This lens is a critical element in the illumination and projection optics train, providing aberration correction and high transmission at 193 nm and 248 nm wavelengths. Its advanced design ensures minimal wavefront distortion and high numerical aperture (NA) for sub-100 nm resolution.

Optical Specifications

• Part Number: 4022.454.48131

• Designation: C2913 / Cymer Lens 750A

• Wavelength Range: 193 nm (ArF) and 248 nm (KrF)

• Focal Length: 750 mm ± 0.5 mm

• Numerical Aperture: 0.75 (variable with aperture stop)

• Material: CaF₂ and UV-grade fused silica with anti-reflection coating

• Transmission: > 96% at 193 nm

• Wavefront Error: < λ/10 RMS at 193 nm

• Diameter: 120 mm (clear aperture 110 mm)

• Mounting: Kinematic mount with three-point adjustment

Functional Description

The C2913 lens operates as a collimator or condenser in the illumination path, shaping the laser beam into a uniform field suitable for reticle illumination. Its multi-element design compensates for chromatic aberration and spherical aberration, ensuring that the image plane receives a diffraction-limited spot. The lens is housed in a temperature-compensated barrel that maintains optical alignment despite ambient temperature fluctuations.

Installation and Alignment

Installation must be performed in a cleanroom environment (Class 10 or better). The lens is mounted on an optical bench using the kinematic base; adjust the three screws to center the lens relative to the optical axis. A laser interferometer is used to verify the tilt and decenter within ±5 arcsec. After mechanical alignment, the lens is locked in place with clamping rings. The purge gas (nitrogen) connections are attached to prevent moisture absorption on the coatings.

Performance Verification

After alignment, performance is verified using a wavefront sensor and a power meter. The transmission at 193 nm is measured and should be within 1% of the specified value. The Strehl ratio is computed from the wavefront data; a value above 0.95 is considered acceptable. The focus position is calibrated using a standard reticle and a CCD camera.

Maintenance and Cleaning

Optical surfaces should only be cleaned by trained personnel using specialized UV-compatible solvents and optical wipes. Inspect the lens annually for coating degradation or particulate contamination. If the transmission drops by more than 3%, the lens may need recoating. The purge system must be maintained at a positive pressure of 0.5 bar above ambient to keep out contaminants.

Integration with Cymer and ASML Systems

This lens is designed for use with Cymer light sources and ASML steppers. It interfaces with the beam delivery unit through a standardized flange. The lens’s orientation is marked with a fiducial arrow; proper orientation ensures correct polarization handling. The lens is compatible with both PAS 5000 and TWINSCAN series with appropriate adapters.

Environmental and Safety

The lens meets SEMI S2-0710 safety requirements for optical components. It is non-hazardous and contains no restricted substances as per RoHS. Operating temperature must be maintained between 20°C and 23°C with stability of ±0.1°C for optimal performance.

Technical Documentation and Support

ASML supplies detailed optical design files, installation manuals, and alignment procedures for the C2913. Training courses are offered for field engineers. Replacement parts, including the kinematic mount and purge fittings, are available from ASML inventory.

Conclusion

The ASML C2913 Cymer Lens 750A is a precision optical component that enables high-resolution DUV lithography. Its superior transmission, wavefront quality, and robust construction make it an indispensable element in modern wafer fabrication.