|
We demonstrated the fabrication of sub-half-micron grating for DBR laser and the study of imaging interferometric lithography (IIL) in this thesis. The sub-half-micron grating is fabricated by the exposure of holographic interference which is an economical method to form a uniform and high resolution grating. For the topic of arbitrary pattern imaging lithography, IIL is applied to extend the resolution of optical lithography to exceed the low-pass spatial frequency (NA/) filter characteristics of the imaging system. Off-axis illumination downshifts the high frequency components of the mask pattern and an interferometric reference beam at the wafer upshifts these frequency components back to their original spatial frequencies. Both refractive and reflective system that can be used for IIL are designed and analyzed. A sub-micron pattern is printed with a simple optical system of restricted NA, that is impossible in the criterion of conventional optical lithography.
|