Diffusion barriers in thin films

▪ Abstract The transition to copper-based interconnects for sub-quarter-micron device technologies has generated significant challenges in the identification and development of the robust material and process technologies required to form reliable multilevel metallization interconnects. In particular, a critical need exists for the identification and development of diffusion barrier/adhesion promoter liner materials that provide excellent performance in preventing the diffusion and intermixing of copper with the adjacent dielectric and semiconductor regions of the computer chip. This review summarizes key technology trends in interconnect metallization, with emphasis on ultrathin liner materials, predominant diffusion mechanisms in liner materials, and most promising candidate liners for copper metallization. Key results are presented from the development of physical vapor deposition and chemical vapor deposition processes for binary refractory metal nitrides, such as tantalum nitride and tungsten nitride...

Ultrathin Diffusion Barriers/Liners for Gigascale Copper Metallization

TaN, Ta3N5, and TaOxNy films were deposited by the atomic layer deposition technique. The alternate surface reactions between TaCl5 and NH3 resulted in Ta3N5 films, but when elemental zinc, serving as an additional reducing agent, was supplied on the substrates between the TaCl5 and NH3 pulses, TaN with a resistivity of 9 × 10-4 Ω cm was obtained. TaOxNy films were grown by depositing first thin Ta3N5 layers which were then partially oxidized by single water pulses. By varying the number of the Ta3N5 deposition cycles between the water pulses, the oxygen-to-nitrogen ratio of the films was controlled. The permittivity of the TaOxNy films was around 30 which is somewhat higher than that of Ta2O5.

Controlled Growth of TaN, Ta3N5, and TaOxNy Thin Films by Atomic Layer Deposition

The chemical vapor deposition (CVD) of metals is a rapidly developing area in which metal-containing compounds are being synthesized as new precursors. This article reviews this area and discusses precursor design, reaction pathways, reactor types, and the influence of reactor operating conditions on film growth. We have gathered recent results for precursor design and CVD chemistry and show how analysis of results from CVD experiments can be used to assist in the development of new CVD precursors.

Chemical vapor deposition of metals: Part 1. An overview of CVD processes

Tantalum and titanium source reagents are described, including tantalum amide and tantalum silicon nitride precursors for the deposition of tantalum nitride material on a substrate by processes such as chemical vapor deposition, assisted chemical vapor deposition, ion implantation, molecular beam epitaxy and rapid thermal processing. The precursors may be employed to form diffusion barrier layers on microelectronic device structures enabling the use of copper metallization and ferroelectric thin films in device construction.

K. Hieber

Papers

Structural and electrical properties of Ta and Ta nitrides deposited by chemical vapour deposition

Structural and electrical properties of evaporated Cr-Ni films as a function of gas pressure

Structural and electrical properties of CrSi2 thin film resistors

Amorphous chromium-silicon: A material for kilo-ohm sheet resistances

Structural changes of evaporated tantalum during film growth