Interference lithography has been widely utilized as a tool for the evaluation of photoresist materials, as well as emerging resolution enhancement techniques. The interferometric approach is both simple and inexpensive to implement, however it is limited in its ability to examine the impact of defocus due to the inherently large DOF (Depth-of-Focus) in two-beam interference. Alternatively, the demodulation of the aerial image that occurs as a result of defocus in a projection system may be synthesized using a two pass exposure with the interferometric method. The simulated aerial image modulation for defocused projection systems has been used to calculate the single beam exposure required to reproduce the same level of modulation in an interferometric system and a graphical representation termed (Modulation Transfer Curve) (MTC) was subsequently developed. An interferometric exposure system was used to experimentally synthesize defocus for modulations of 0.3, 0.5, 0.7 and 1.0. Feature sizes of 90nm were evaluated across dose and synthetic focus.
Library of Congress Subject Headings
Photolithography; Interferometry; Optical data processing
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Smith, Bruce - Chair
Cropanese, Frank, "Synthesis of low k1 projection lithography utilizing interferometry" (2006). Thesis. Rochester Institute of Technology. Accessed from
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