Improving lithography pattern fidelity and line-edge roughness by reducing laser speckle
Schematic of single-pulse speckle measurement setup for the XLA 360 dual-chamber MOPA laser system with two stages of OPuS.
Measured single-pulse laser speckle as a function of increasing pulse duration; speckle contrast is 16% (a), 9% (b), and 6% (c) for the images from top to bottom.
SEM micrograph ( FOV, symmetric magnification) of photoresist line-space pattern imaged using dry lithography for (a) standard OPuS and (b) short-duration pulse (without OPuS).
(a) immersion 2D five-bar pattern modeled as a function of characteristic speckle grain size at 1% contrast; left-hand side image is the input aerial image without the additive speckle intensity; (b) modeled LWR as a function of speckle contrast for grain size of .
(a) Experimental LWR measurements for dry ArF and different feature types for no OPuS and with one-stage OPuS (POR); (b) LWR as a function of effective pulse duration for line/ pitch photoresist structures imaged using immersion lithography; error bars represent range over 80 SEM images taken at each OPuS condition.
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