Interference lithography system consisting high precision pitch control and automatically beam alignment modules

The interference lithography is a promising technique for waveguide combiners and distributed feedback laser diodes. However, the technology has not been applied in mass production due to three issues. The first is an insufficient fringe pitch accuracy. The second is a deterioration of patterning quality due to low exposure contrast. And, last is time consuming alignment processes. We have developed an interference lithography system applied with technologies of a high precision wafer stage, a diode pumped solid-state laser with a wavelength of 266 nm and high accuracy actuators. The system has a patterning pitch accuracy of 0.01 nm, a patterning direction angle accuracy of 0.01 degree, an ability to form clear patterns with excellent exposure contrast and an automatical beam alignment for capability of mass production. We will present an overview of the system for achieving the specifications, and examples of processing.