Abstract
A method is described for quick alignment of photolithographic masks over silicon substrates. Moiré reflection patterns are observed from grids etched on the silicon wafer and grids located on the photolithographic masks. A restricted class of moiré patterns provides information on both the direction and degree of misalignment during all phases of alignment. Alignment accuracy of 0.2 μm has been achieved even when there were separations of 30 μm between the mask and wafer. The moiré patterns can be observed visually through standard mask-alignment facilities. The etched grids are found to retain their diffraction properties during the operations of reoxidation and epitaxial growth.
© 1972 Optical Society of America
Full Article | PDF ArticleMore Like This
Feng Xu, Shaolin Zhou, Song Hu, Wenbo Jiang, Liang Luo, and Hongyu Chu
Opt. Express 23(16) 20905-20915 (2015)
S. Yokozeki and T. Suzuki
Appl. Opt. 11(2) 446-448 (1972)
Donald E. Duffy
Appl. Opt. 11(8) 1778-1781 (1972)