Differential interferometer

The RLD10-X3-DI differential interferometer detector head allows measurement of the relative displacement between a fixed, reference mirror, and a moving, measurement mirror. Particularly suited for vacuum and controlled environment applications, the RLD10-X3-DI detector head has been designed to mount to the external wall of a process chamber via a simple three-pin mount. There is no need to enter the chamber to align the detector head - integral beam steerers allow independent pitch and yaw adjustment of reference and measurement beam - and the design of the mounting system allows the detector head to be removed and repositioned with minimal effect on system alignment.

Specification

Figures are based on using the RLD10-X3-DI head with an RLU20 laser unit

Features and benefits

• Exceptional metrology
  ppb frequency stability and ultra low cyclic error, allowing output resolutions to 38.6 pm.
• Differential configuration
  Measures the relative position of stage versus column, or workpiece versus tool, and eliminates common mode errors such as motion of the chamber sidewall associated with environmental fluctuations.
• Rapid alignment
  Simple alignment from outside the process chamber using four integrated beam steerers (±1° pitch and yaw adjustment for both measurement and reference beams) to overcome chamber and mirror mounting tolerances.