As well as measuring CD, monitoring pattern profile is becoming important for semiconductor metrology. Illuminating
the wafer and detecting the reflective light, reflective light intensity in the Fourier space includes the information of CD
and pattern profile variation by form birefringence effect. CD change and profile variation could be detected separately
for the actual wafer. Mathematical simulation is presented the background of our unique approach. The detail results of
CD and pattern profile monitor is shown in this paper.
It is becoming increasingly important to monitor wafer edge profiles in the immersion lithography era. A Nikon edge
defect inspection tool acquires the circumferential optical images of the wafer edge during its inspection process. Nikon's
unique illumination system and optics make it possible to then convert the brightness data of the captured images to
quantifiable edge profile information. During this process the wafer's outer shape is also calculated. Test results show
that even newly shipped bare wafers may not have a constant shape over 360 degree. In some cases repeated deformations with 90 degree pitch are observed.
We tried to detect the CD variation of the 4x generation hole pattern using the diffraction light on Fourier space with the
polarized light and the modified illumination.
The new technology named DD (Dual Diffraction) method has been developed based on the optical simulation and the
experimental approaches. We introduce the case of detection for the diameter variation on a multi-layered hole pattern
with new method.