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Interconnect RC delay, predominantly affected by the effective dielectric constant (k-value) and by the copper resistivity ([rho] cu), is an important performance metric for back-end-of-line (BEOL) process assessment. As process technology scales, interpretation of fundamental process-induced RC delay variations becomes a challenge as the relative importance of statistical process-induced fluctuations (variation of critical dimensions during plasma etching of low-k materials, line profiles, thickness nonuniformity, etc.) grows rapidly and begins to show. A more accurate interpretation of experimental data and prediction of future performance trends requires a more realistic assessment that accounts for such statistical fluctuations. In this paper, an inventory of the most common possible sources of statistical process-induced RC delay variations is made, parameterized, and subsequently used to generate a realistic 2-D interconnect model from which, R and C, and thereby RC delay, are computed. For both wire resistivity and RC, response surface models (RSM) are subsequently generated based on the results of a full factorial design-of-experiment analysis with these input parameters. Finally, based on the RSMs, an improved methodology of interconnect performance evaluation is proposed. Index Terms--Capacitance, copper, delay circuit, modeling, RC circuits, resistivity, variability.

We investigated plasma treatment induced water absorption in a SiOCH low-k dielectric and the influence of the absorbed water components on the low-k dielectric reliability. By using thermal desorption spectroscopy (TDS), water absorption in SiOCH was evidenced for N2/H2 plasma treatments. Based on these TDS results, two anneal temperatures were selected to separate and quantify the respective contributions of two absorbed water components, physisorbed (α) and chemisorbed (β) water, to low-k dielectric reliability. With the physisorbed water desorbed by an anneal at 190 °C, the low-k dielectric shows reduced leakage currents and slightly improved time-dependent dielectric breakdown (TDDB) lifetimes. However, the observed failure mechanism represented by the TDDB thermal activation energy (Ea) does not change until the chemisorbed water component was desorbed by an anneal at 400 °C. The close similarity between Ea and the bond energy associated with the β water component demonstrates that the β bond is among the weakest links for the SiOCH low-k dielectric breakdown. [ABSTRACT FROM AUTHOR]

Plasma treatment induced water absorption in a SiOCH low-k dielectric and the affect of the absorbed water components on the low-k dielectric reliability are examined. The close similarity between the thermal activation energy and the bond energy associated with the chemisorbed ([beta]) water component has shown that the [beta] bond is among the weakest links for the SiOCH low-k dielectric breakdown.

Abstract: We report on the synthesis of Cu3Ge films by exposing Cu films to germane (GeH4). The process window was established by investigating the influence of the GeH4 partial pressure, the soak temperature, and the soak time on Cu films of different thickness. It is shown that short exposures of germane led to Cu-rich germanides, while an excessive GeH4 supply resulted in a Cu3Ge/Ge mixed phase. The germanidation reaction was found to be selective and required the prior removal of the native Cu oxide by in situ plasma cleaning. X-ray diffraction and transmission electron microscopy showed that the Cu3Ge films were crystalline as deposited in the orthorhombic phase and were textured. The films were homogenous in composition. Thin films consisted of Cu3Ge islands connected by a thin wetting layer. Fully continuous layers were however found for larger film thicknesses. The continuity of the Cu3Ge film was also found to be influenced by the pseudosubstrate: the films were more continuous on TaN/Ta than on SiO2. The electric properties of the Cu3Ge films on both TaN/Ta and SiO2 pseudosubstrates are presented and compared. [Copyright &y& Elsevier]