12 February 1997 Comparison of line shortening assessed by aerial image and wafer measurements
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Abstract
Increasing number of patterns per area and decreasing linewidth demand enhancement technologies for optical lithography. OPC, the correction of systematic non-linearity in the pattern transfer process by correction of design data is one possibility to tighten process control and to increase the lifetime of existing lithographic equipment. The two most prominent proximity effects to be corrected by OPC are CD variation and line shortening. Line shortening measured on a wafer is up to 2 times larger than full resist simulation results. Therefore, the influence of mask geometry to line shortening is a key item to parameterize lithography. The following paper discusses the effect of adding small serifs to line ends with 0.25 micrometer ground-rule design. For reticles produced on an ALTA 3000 with standard wet etch process, the corner rounding on them mask can be reduced by adding serifs of a certain size. The corner rounding was measured and the effect on line shortening on the wafer is determined. This was investigated by resist measurements on wafer, aerial image plus resist simulation and aerial image measurements on the AIMS microscope.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Wolfram Ziegler, Rainer Pforr, Joerg Thiele, Wilhelm Maurer, "Comparison of line shortening assessed by aerial image and wafer measurements", Proc. SPIE 3236, 17th Annual BACUS Symposium on Photomask Technology and Management, (12 February 1997); doi: 10.1117/12.301203; https://doi.org/10.1117/12.301203
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