Paper
23 March 2011 Lithography process control using focus and dose optimisation technique
Nicolas Spaziani, René-Louis Inglebert, Jean Massin
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Abstract
As design rules continue to shrink, it is increasingly important to be able to determine and separate sources of Critical Dimension (CD) errors in order to maintain ever-decreasing process windows. CD errors can mainly be attributed to lack of focus and dose control1. Today some of these errors go undetected and CD changes are corrected by making dose correction to the exposure tool. However, corrections using only dose can lead to significantly smaller process latitudes. Therefore, it is very important that we consider dose and focus as a pair to increase the CD uniformity. The model we use is based on Ausschnitt deconvolution method1, 2. This model calculates the dose and focus errors simultaneously from CD parameters, such as bottom CD and top CD information, measured by a scatterometry measurement tool. We have confirmed that this method controls photoresist shape and photoresist width accurately and reduces the CD variation for 40 nm devices by 50%.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Nicolas Spaziani, René-Louis Inglebert, and Jean Massin "Lithography process control using focus and dose optimisation technique", Proc. SPIE 7973, Optical Microlithography XXIV, 79732Z (23 March 2011); https://doi.org/10.1117/12.879074
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Cited by 2 patents.
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KEYWORDS
Critical dimension metrology

Photoresist materials

Scatterometry

Semiconducting wafers

Control systems

Scatter measurement

Deconvolution

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