How target material behaves during chip manufacturing has been misunderstood for years
Researchers discovered that titanium nitride targets used in semiconductor production don't form as expected during sputtering—a finding that challenges decades of industrial assumptions. The discovery could improve thin film quality and help manufacturers better predict and control their coating processes.
Originaltitel: Native target chemistry during reactive dc magnetron sputtering studied by ex-situ x-ray photoelectron spectroscopy
<p>We report x-ray photoelectron spectroscopy (XPS) analysis of native Ti target surface chemistry during magnetron sputtering in an Ar/N-2 atmosphere. To avoid air exposure, the target is capped immediately after sputtering with a few-nm-thick Al overlayers; hence, information about the chemical state of target elements as a function of N-2 partial pressure p(N2) is preserved. Contrary to previous reports, which assume stoichiometric TiN formation, we present direct evidence, based on core-level XPS spectra and TRIDYN simulations, that the target surface is covered by TiNx with x varying in a wide range, from 0.27 to 1.18, depending on p(N2). This has far-reaching consequences both for modelling of the reactive sputtering process and for everyday thin film growth where detailed knowledge of the target state is crucial. Published by AIP Publishing.</p>