ABSTRACT
The continual demands to shrink device sizes and length scales in the semiconductor industry have accelerated the adoption
of X-ray photoelectron spectroscopy (XPS) as a critical step for in-line metrology. The technique was initially introduced
to the in-line environment to measure ultrathin layers and layer stacks predominantly in the gate module. As these stacks
and related structures increase in complexity through scaling, a more rigorous assignment of spectral components to their
material intensity source is necessary to use the full potential of XPS. In this paper, the application areas for in-line XPS
are reviewed and modeling practices are demonstrated that significantly enhance XPS measurement characterization
related to gate-all-around (GAA) transistor architectures. Besides traditional measurements on non-patterned areas, the
high surface sensitive nature of XPS may also be tailored specifically for use on fully integrated targets. For example,
successful quantification of material residues remaining on active device areas is presented and discussed. Such
measurements directly on device are particularly significant as dedicated measurement targets may not serve as a proxy
for active areas anymore. The need for advanced XPS modeling capabilities beyond 1D film stack characterization and
towards direct 2D/3D measurement on fully integrated structures will be highlighted.
Keywords: X-ray photoelectron spectroscopy, gate-all-around, in-line metrology, in-line XPS, advanced XPS, XRF
*Corresponding author: [email protected]
