Research of measurement and measuring error of laser interferometer in step imprint lithography

To the nano-position measurement of imprint lithography process, when the Michelson interference theory is used in laser interferometer measuring system in common environment conditions, it is difficult to avoid the disturbing error, which is fatal to measuring result. Through analyzing and calculating the Edlen formula, not only the influence from changes of temperature, humidity, and atmospheric pressure in measuring environment to laser interferometer measurement accuracy is theoretically revealed, but also the most serious disturbance coming from the flowing air is proved. By adopting the isolating mask of air flow and compensating feedback controller in measuring system, the phase-shift error between two laser interference signals can be compensated in real-time. At last, the measuring drifting error can be reduced from 13 nm to 5 nm in 10 minutes and this optimized measuring system can be used in the imprint lithography and match to the needs of 20 nm positioning accuracy in 100 mm motion range.