Integration methodology of chemical vapor deposition TiN, chemical vapor deposition W and W chemical mechanical planarization for sub-quarter micron process application

Abstract

Chemical vapor deposition (CVD) W plugs have been widely used for device metallization with excellent conformity in small contacts/vias with high aspect ratio [J. E. J. Schmitz, Chemical Vapor Deposition of Tungsten and Tungsten Silicides (Noyes, 1991)]. However, some unexpected plug fill such as plug loss and key hole exposing post tungsten chemical mechanical planarization (WCMP) still happened while going to smaller plug size and using metalorganic chemical vapor deposition (MOCVD) TiN barrier. In this study, MOCVD TiN and CVD W fill followed by WCMP for plug metallization were investigated. Extensive analysis had been conducted on various types of defective W plugs. Organic contaminants (hydrocarbon by-products) in MOCVD TiN deposition would prevent W deposition taking place inside the plug. For W wise, lower process temperature, carefully adjusted WF6/SiH4 and WF6/H2 partial pressure ratios had demonstrated better plug fill and electrical performance [T. E. Clark et al., J. Vac. Sci. Technol. B 9, 1478 (1991)]. In the WCMP approach, the effects of different oxidizer concentration in slurry were characterized. Eliminating the seam formation during the CVD W process can help avoid slurry attack in WCMP. The optimized integration scheme of MOCVD TiN barrier, CVD W, and WCMP was successfully achieved and is applied on 0.20 μm Logic production.