TY - JOUR
T1 - Applicability of X-ray fluorescence spectroscopy as method to determine thickness and composition of stacks of metal thin films: A comparison with imaging and profilometry
AU - Vrielink, J.A.M.
AU - Tiggelaar, Roald M.
AU - Gardeniers, Johannes G.E.
AU - Lefferts, Leonardus
PY - 2012/8/22
Y1 - 2012/8/22
N2 - In this work the applicability of X-ray fluorescence spectroscopy (XRF) for fast, accurate and non-destructive determination of the thickness of a variety of single-layer and multi-layer metal thin films deposited on glass and silicon is investigated. Data obtained with XRF is compared with information from profilometry and images from scanning electron microscopy (SEM). Whereas thickness determinations based on profilometry and cross-sectional SEM-imaging have restrictions with respect to thickness of metal stacks or hardness of the metals, XRF has no such limitations. Moreover, XRF can discriminate between sublayers in a multi-layer film, and can also be utilized for compositional analysis and density estimations. Good agreement between thickness data obtained with XRF, profilometry and SEM-images is found, under the justifiable assumption that the density of sputter-deposited and evaporated thin films is ca. 5% below that of bulk metals. Similar XRF-results are found for non-patterned areas (64 mm2 metal) as well as lithographically patterned areas containing a series of small metal lines (total metal surface ca. 8 mm2). As a consequence, it is concluded that XRF is a versatile technique for analysis, verification, control or evaluation of the thickness, density or (elemental) composition of thin metal film line-patterns, during their fabrication as well as prior or post to applications.
AB - In this work the applicability of X-ray fluorescence spectroscopy (XRF) for fast, accurate and non-destructive determination of the thickness of a variety of single-layer and multi-layer metal thin films deposited on glass and silicon is investigated. Data obtained with XRF is compared with information from profilometry and images from scanning electron microscopy (SEM). Whereas thickness determinations based on profilometry and cross-sectional SEM-imaging have restrictions with respect to thickness of metal stacks or hardness of the metals, XRF has no such limitations. Moreover, XRF can discriminate between sublayers in a multi-layer film, and can also be utilized for compositional analysis and density estimations. Good agreement between thickness data obtained with XRF, profilometry and SEM-images is found, under the justifiable assumption that the density of sputter-deposited and evaporated thin films is ca. 5% below that of bulk metals. Similar XRF-results are found for non-patterned areas (64 mm2 metal) as well as lithographically patterned areas containing a series of small metal lines (total metal surface ca. 8 mm2). As a consequence, it is concluded that XRF is a versatile technique for analysis, verification, control or evaluation of the thickness, density or (elemental) composition of thin metal film line-patterns, during their fabrication as well as prior or post to applications.
KW - METIS-278072
KW - IR-83158
U2 - 10.1016/j.tsf.2011.08.049
DO - 10.1016/j.tsf.2011.08.049
M3 - Article
SN - 0040-6090
VL - 520
SP - 1740
EP - 1744
JO - Thin solid films
JF - Thin solid films
IS - 6
ER -