1 July 1991 Study of the relationship between exposure margin and photolithographic process latitude and mask linearity
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Proceedings Volume 1463, Optical/Laser Microlithography IV; (1991); doi: 10.1117/12.44784
Event: Microlithography, 1991, San Jose, CA, United States
Abstract
The utility of exposure margin, defined as the ratio between the 1:1 mask reproduction exposure energy and the open frame threshold exposure energy (E0), as an indicator of process latitude, is probed using extensive computer simulations and some experimental photolithography. The correlation is shown to be excellent for latitudes which depend primarily on critical dimension such as mask linearity and exposure latitude: a high exposure margin implies a high process latitude. Qualitative physical arguments are offered to explain this. For sidewall angle constrained latitudes such as defocus, the correlation is also good if comparing photoresists with similar optical absorption characteristics. These results are potentially significant because exposure margin is easily measured and therefore provides an efficient means for process optimization (at zero mask bias). As part of this work a simulation procedure which reduces the focus: exposure: mask dimension latitude to a single process latitude volume was developed and is described.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Steven G. Hansen, Giang T. Dao, Henry T. Gaw, Qi-De Qian, Peggy M. Spragg, Rodney J. Hurditch, "Study of the relationship between exposure margin and photolithographic process latitude and mask linearity", Proc. SPIE 1463, Optical/Laser Microlithography IV, (1 July 1991); doi: 10.1117/12.44784; https://doi.org/10.1117/12.44784
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KEYWORDS
Photomasks

Absorption

Optical lithography

Critical dimension metrology

Photoresist materials

Photoresist developing

Computer simulations

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