RLD10 differential interferometer
Differential interferometers allow measurement relative to defined reference.
The differential head is designed with a unique optical scheme to achieve a low SDE performance. Integrated beam steerers allow for pitch and yaw adjustment during set up which improves the alignment process (only suitable for plane mirror 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.
Features and benefits
- Exceptional metrology -ppb frequency stability and ultra low cyclic error, allowing output resolutions to 38.6 pm.
- Differential configurations – measures the relative position of the stage relative to the column, therefore eliminating common mode errors such as motion of the chamber side wall associated with environmental fluctuations.
- Rapid alignment – simple alignment from outside the vacuum chamber using four integrated beam steerers to overcome chamber and mirror mounting tolerances.
|0 m – 1 m
|Resolution (resolution configured with RLU)
|Analogue quadrature = λ/4 (158 nm)
Digital quadrature = 10 nm
RPI20 resolution = 38.6 pm
|System non-linearity error* (SDE)
|<±1 nm below 50 mm/sec with >70% signal strength
<±6 nm at 1 m/sec with >50% signal strength
|Up to 1 m/s