Measurement results on after etch resist coated features on the new Leica Microsystems' LWM270 DUV critical dimension metrology system

摘要

Process control in photomask manufacturing is crucial for improving and maintaining optimal yields. The LWM270DUV critical dimension (CD) measurement system is the first tool ever designed for photomask manufacturers that combines both UV (365 nm wavelength light) and DUV (248 nm wavelength light) for CD measurements. UV light illumination was integrated into the LWM270 DUV to allow photomask makers to perform after etch inspection (AEI) on DUV resists minimizing exposure effects. The increased resolution of UV illumination allows for measurement of features as small as 300 nm. Improved measurement algorithms as well as improvements in the illumination system have reduced the uncertainty of measurements resulting in improved performance. This paper details recent measurement results of various feature types on different substrate types using UV transmitted light.