Cu(ReTaNx) Copper Alloy Films Suitable for Electronic-Device Manufacturing-Process Simplification

• Published in: Japanese Journal of Applied Physics 2012-01, Vol.51 (1), p.01AC08-01AC08-7
• Main Author: Lin, Chon-Hsin
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.51.01AC08

In this study, we prepare Cu(ReTa) and Cu(ReTaN x ) films via reactive cosputtering of copper (Cu), rhenium (Re), and tantalum (Ta) on a barrierless silicon (Si) substrate in an argon--nitrogen (Ar--N 2 ) atmosphere. These Cu(ReTa) and Cu(ReTaN x ) films, after annealing at 630 and 750 °C for 1 h, exhibit two values of resistivity, viz. , 3.05 and 2.35 μ$\Omega$ cm, respectively, showing high thermal stability without copper-silicide formation. The Cu(ReTaN x ) film's up-to-750 °C high-temperature stability, while maintaining a low leakage current and resistivity, appears to make it a good candidate material for advanced barrierless metallization for simplifying related electronic-device manufacturing processes, and, consequently, reducing the related manufacturing cost. Applying X-ray diffraction (XRD), focused ion-beam microscopy, and transmission electron microscopy (TEM) to evaluate said film, we observed that the Cu seed layer-Si interface showed no detrimental reaction after the film was annealed at 750 °C for 1 h. The film, hence, is recommended for the desired purpose.