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.
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.
As the semiconductor design rules shrink down, process margins are getting narrower, and thus, it is getting more
important than ever to monitor pattern profile and detect minor structure variation. A breakthrough technology has been
introduced as a solution to this concern. The new technology converts the fluctuation of polarization ingredient, which is
caused by form birefringence, into light intensity variations as an optical image. This technology, which is called Pattern
Edge Roughness (PER) inspection mode, is proved to be effective for 55nm production process. We also studied the
possibility of the macro inspection method for half pitch 32nm technology node through FDTD method.