A novel high-resolution XRD apparatus for patterned epitaxial films in a 50pm pad area with a convergent micro X-ray beam

A novel high-resolution X-ray diffraction (HR-XRD) apparatus for patterned epitaxial thin films has been developed using a convergent micro X-ray beam and a 2D detector. The micro-spot and high-flux (6 × 10
⁷
photons/s) X-ray beam was achieved by using a hybrid mirror that consists of a bent crystal and a multilayer mirror and enabled measurement of patterned film in a 50 μm square (pad) area. We demonstrated rocking curve (RC) measurements of a Si
_(1-x)
Ge
_x
epitaxial thin film (x was 13.5% and thickness was 50nm) and calculated Ge concentration, thickness, strain, and stress based on the measured results. We obtained precision (3c) of Ge concentration of 0.10% by 100 s and 0.27% by 10 s X-ray exposure time by the analysis. We also carried out reciprocal space mapping (RSM) of the Si
_(1-x)
Ge
_x
and we obtained that Ge concentration of 13.38% using RSM data, whereas 13.46% using RC measurement data. We confirmed that the HR-XRD tool enabled short time measurement and making it appropriate for in-line inspection of Si
_(1-x)
Ge
_x
and other thin crystalline films on patterned wafers.