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We present the results of a systematic benchmarking study, using 45nm-groundrule structures, of a commercially-available ionized PVD Cu technology which employs an in-situ Ar+ radio-frequency (Rf) plasma capability for enhanced coverage, and compare its performance and extendibility against the same seedlayer process operated in conventional low-pressure mode. Studies of single-damascene lines and dual-damascene via structures indicate that the PVD Cu seedlayer with Rf-Plasma enhancement enables a reduction of the PVD Cu seed thickness on the order of 35%, based on studies of Cu voiding, via-yield degradation, and transmission-electron microscopy (TEM). These results illustrate the critical importance of the Rf-plasma resputter capability in extending the PVD Cu process to advanced groundrules at 45nm and beyond.

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Material and process studies in the integration of plasma-promoted chemical-vapor deposition of aluminum with benzocyclobutene low-dielectric constant polymer Results are presented from a proof-of-concept study that examined the integration of damascene-processed thermal chemical vapor deposited ͑TCVD͒ aluminum ͑Al͒ interconnects in a benzocyclobutene ͑BCB͒ polymer matrix. In a first phase, the study identified baseline deposition conditions for the formation of structurally and chemically compatible blanket Al/titanium nitride ͑TiN͒/BCB stacks on two types of blanket BCB substrates utilized to simulate the actual surfaces encountered in typical damascene processing: ͑1͒ blanket BCB films capped with a silicon dioxide SiO 2 layer (SiO 2 -BCB), and ͑2͒ plasma reactive ion etched blanket BCB films. The TiN diffusion barrier was grown in two stages. A first ͑bottom͒ layer was deposited by physical vapor deposition ͑PVD͒, followed by a CVD-grown top layer. The resulting TCVD Al/CVD TiN/PVD TiN/BCB stacks were stable under thermal stressing up to 325°C for 1 h. In a second phase, an optimized TCVD Al process flow was developed for void-free filling of TiN-coated 320-nm-wide trenches etched in a BCB matrix. The process flow included the demonstration of a chemical mechanical polishing recipe for planarization of the patterned TCVD Al/CVD TiN/PVD TiN/BCB structures. The resulting findings were incorporated in the fabrication of electrically testable TCVD Al/CVD TiN/PVD TiN/BCB interconnect structures on 200 mm wafers. Electrical evaluation for shorting and leakage of the test dice produced an adequate yield for the feasibility study of ϳ71% of screened test sites. The electrical tests also generated an upper-bound value of 4.2 ⍀ cm for Al line resistivity, a number that did not include corrections for contact resistance and interfacial scattering. These findings demonstrate the feasibility of TCVD Al/BCB based metallization schemes, particularly in terms of chemical, structural, mechanical, and electrical performance.

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