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This paper outlines yield improvements in the integration of damascene copper in low-k SiCOH intermetal dielectric at 65 nm dimensions. Large defect reductions were seen by RIE, wet cleans and CMP process optimization. RIE improvements led to reductions of thirty three percent for missing pattern defects while wet clean optimization resulted in more than a fifty percent reduction in metal voids. CMP carrier head changes provided a more corrosion resistant process and higher throughput. Additionally, a high performance M1 module that maintained process window for all sectors was developed.

Fluorinated silica has a dielectric constant lower than that of F-free SiO2 and is a potential interlayer dielectric. We investigate the F-doped SiO2 with ab-initio modeling and various characterization techniques searching to explain the dielectric constant reduction. FTIR transmission and spectroscopic ellipsometry give us information about the ionic and electronic contributions to ε. Nuclear reaction analysis and Auger spectrometry measure F composition. XPS and FTIR provide information on the atomic structure of the film. We use several cells of cristobalite to model fluorinated silica using the electronic structure theory. The ground state geometry, vibrational density of states, electronic band structure, and Born effective charges are analyzed. The calculations suggest that it is the ionic component of the dielectric constant that is mostly effected by the F incorporation.

With the continuing aggressive scaling of interconnect dimensions and introduction of new lower k materials, dielectric TDDB reliability margin is greatly reduced. In this paper, a comprehensive investigation on an abnormal low-k TDDB characteristic, a systematic degradation of Weibull slopes at lower stress voltages, was conducted for Cu and CuMn alloy interconnect with porous ultra low-k (ULK) CVD dielectric (k=2.4). Based on extensive electrical and physical evidences, such abnormal TDDB characteristic was attributed to slow metallic diffusion in bulk ULK induced by Mn and Cu segregation. A new TDDB model based on invasion percolation was proposed to successfully model the observed abnormality. CuMn interconnect with robust liner to assure metal free ULK has become important for TDDB reliability.

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