TY  - JOUR
U1  - Zeitschriftenartikel, wissenschaftlich - begutachtet (reviewed)
A1  - Al Ktash, Mohammad
A1  - Stefanakis, Mona
A1  - Englert, Tim
A1  - Drechsel, Maryam
A1  - Stiedl, Jan
A1  - Green, Simon
A1  - Jacob, Timo
A1  - Boldrini, Barbara
A1  - Ostertag, Edwin
A1  - Rebner, Karsten
A1  - Brecht, Marc
T1  - UV hyperspectral imaging as process analytical tool for the characterization of oxide layers and copper states on direct bonded copper
JF  - Sensors
N2  - Hyperspectral imaging and reflectance spectroscopy in the range from 200–380 nm were used to rapidly detect and characterize copper oxidation states and their layer thicknesses on direct bonded copper in a non-destructive way. Single-point UV reflectance spectroscopy, as a well-established method, was utilized to compare the quality of the hyperspectral imaging results. For the laterally resolved measurements of the copper surfaces an UV hyperspectral imaging setup based on a pushbroom imager was used. Six different types of direct bonded copper were studied. Each type had a different oxide layer thickness and was analyzed by depth profiling using X-ray photoelectron spectroscopy. In total, 28 samples were measured to develop multivariate models to characterize and predict the oxide layer thicknesses. The principal component analysis models (PCA) enabled a general differentiation between the sample types on the first two PCs with 100.0% and 96% explained variance for UV spectroscopy and hyperspectral imaging, respectively. Partial least squares regression (PLS-R) models showed reliable performance with R2c = 0.94 and 0.94 and RMSEC = 1.64 nm and 1.76 nm, respectively. The developed in-line prototype system combined with multivariate data modeling shows high potential for further development of this technique towards real large-scale processes.
KW  - hyperspectral imaging
KW  - pushbroom
KW  - UV spectroscopy
KW  - principal component analysis
KW  - partial least squares regression
KW  - direct bonded copper
KW  - copper oxide layer thickness
Y1  - 2021
UN  - https://nbn-resolving.org/urn:nbn:de:bsz:rt2-opus4-32949
U6  - https://doi.org/10.3390/s21217332
DO  - https://doi.org/10.3390/s21217332
VL  - 21
IS  - 21
SP  - 13
S1  - 13
PB  - MDPI
CY  - Basel
ER  -