| AVS 62nd International Symposium & Exhibition | |
| Materials Characterization in the Semiconductor Industry Focus Topic | Tuesday Sessions |
| Session MC-TuP |
| Session: | Materials Characterization in the Semiconductor Industry Poster Session (All areas) |
| Presenter: | Mohammad Faheem, GLOBALFOUNDRIES Inc. |
| Authors: | M. Faheem, GLOBALFOUNDRIES Inc. P. van der Heide, GLOBALFOUNDRIES, Inc. O. Wood, GLOBALFOUNDRIES Inc. Y. Liang, GLOBALFOUNDRIES Inc. A. Kumar Kambham, GLOBALFOUNDRIES Inc. K. Wong, GLOBALFOUNDRIES Inc. V. Park, GLOBALFOUNDRIES Inc. P. Mangat, GLOBALFOUNDRIES Inc. |
| Correspondent: | Click to Email |
Future photomasks for extreme ultra violet lithography (EUVL) would be improved with broader bandwidth reflective multilayer coatings especially below the 7 nm technology node. Owing to its lower index of refraction, higher numerical aperture and contamination resistance Ruthenium (Ru) is a potential candidate for use on future generation EUVL masks. We characterized 20 layer stacks of Si/La, Si/Ru and Si/B4C/Ru on Si (100) substrates. X Ray Reflectivity (XRR) and Atom Probe Tomography (APT) were carried out on a Si/La stack for period comparison. Si/Ru and Si/B4C/Ru were prepared for phase comparison using XRR and X Ray Diffraction (XRD). Four samples of Si/B4C/Ru multilayers with less than 1 Å period difference were compared using synchrotron-based EUV reflectometry.
XRR measurements were carried out using a Bruker D8 Discover with Cu K-alpha (λ = 1.542 Å) and a scintillator detector. Measurements were made at small detector angles, 2θ = 0-10o. For texture and crystallite size, locked coupled scans were carried out using 0.2 mm beam slit and Lenxeye detector in 1D mode along 2θ = 10-110o. Bruker’s Eva software was used to measure the peak positions and the ICDD PDF-4 data base was used to identify the Ru peaks. The APT measurements were performed by LEAP 4000X-Si instrument under UV laser illumination.
The result indicates the close agreement between XRR and APT for a 20 layer La/Si stack. XRR spectra of Si/Ru and Si/B4C/Ru showed the multilayer period of ~ 7nm with sharp peaks which indicate the uniformity of deposited multilayers. Ru and B4C showed polycrystalline behavior compared to amorphous Si. XRD results demonstrate that Ru layers tend to have (002) texture both in Si/Ru and Si/B4C/Ru samples. Ru crystallite size in Si/Ru was observed to be larger than in Si/B4C/Ru. The difference in crystallite size can be due Ru film thickness and its deposition on Si and B4C. In the case of four Si/B4C/Ru samples, the change in period was found to be correlated to changes in bandwidth and shifts in the position of peak EUV reflectivity. These results are not only of fundamental importance but also beneficial for improving the performance of Ru-based EUVL reflectors.
Key words: EUVL, XRR, XRD, APT, Synchrotron
*Corresponding author, Tel: (518) 305 7837, Fax: (518) 305 6587
Email address: Mohammad.Faheem@Globalfoundries.com [mailto:Mohammad.Faheem@Globalfoundries.com]