Optical metrology techniques are essential for process control of the gate formation process steps from lithography to the
dielectric, spacers, gate and straining layer deposition in the sub-65nm technology nodes. Traditionally, optical metrology
is based on the measurements of periodic lines or hole arrays using a spectroscopic ellipsometer or reflectometer,
collecting data across a wavelength range at a single angle of incidence. In this paper, we discuss measurements using
Focused Beam Ellipsometry (FBE), illuminating at discrete laser wavelengths while data is collected over a wide angle
of incidence range. We verify precision estimates of the different model parameters with actual values obtained from
measured data. We show sensitivity ranges for different applications over the space of measured wavelength spectrum
from DUV to IR, angle of incidence range, and sample azimuthal orientations. Major factors contributing to the projected
recipe performance - wavelength, orientation of the incident beam are discussed.
In the sub-90 nm technology nodes, optical metrology techniques are essential for process control of gate formation
steps, from lithography to etch layers such as gate, trench, and dielectric interconnect layers and to spacers and straining
layer depositions. Conventionally, optical metrology is based on measurements of periodic line or hole arrays
(i.e., gratings) using spectroscopic ellipsometers or polarized reflectometers, collecting data across wide wavelength
spectra at a single angle of incidence. In this paper, we present results of measurements on periodic etched amorphous-Si gate line arrays using focused beam ellipsometry (FBE), illuminating at three discrete laser wavelengths while data is
collected over angles of incidence ranging from 45° to 65°. Results on thoroughly characterized samples representative
of 65 and 45 nm technology are presented. These samples include a variety of both line critical dimensions (CDs) (from
18-50 nm) and line pitches (from 200-700nm) for dense and isolated lines arrays. We discuss precision and accuracy in
terms of total measurement uncertainty; spot size, navigation, and tool matching are also presented. FBE-based metrology
will meet current process control requirements within a substantial margin.
Optical metrology techniques are essential for process control of gate formation process steps from lithography to the
dielectric, spacers, gate and straining layer deposition in sub-90nm technology nodes. Traditionally, optical metrology is
based on the measurement of periodic lines or hole arrays using a spectroscopic ellipsometer or reflectometer, collecting
data across a wide wavelength spectrum at a single angle of incidence. In this paper, we present results of measurements
on periodic Poly-Si gate line arrays using laser based Focused Beam Scatterometry (FBS), illuminating at 3 discrete
laser wavelengths while data is collected over an angle of incidence range from 45° to 65°. Accuracy, repeatability, and
tool-to-tool matching results for the poly-Si gate line arrays are discussed. Comparison with the CD-SEM and cross-section
TEM result for measurement/modeling accuracy is also presented.
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