Simple model system for fabrication of integrated circuit interconnects. (General Developments).Electrodeposition e·lec·tro·de·pos·it tr.v. e·lec·tro·de·pos·it·ed, e·lec·tro·de·pos·it·ing, e·lec·tro·de·pos·its To deposit (a dissolved or suspended substance) on an electrode by electrolysis. n. The substance so deposited. has recently and unexpectedly evolved with a major role in on-chip metallization Met`al`li`za´tion n. 1. The act or process of metallizing. , which provides the interconnects between transistors, etc. in an integrated circuit. The understanding of copper deposition for this particular application has been elucidated through the Curvature Enhanced Accelerator Coverage (CEAC CEAC Chemical Engineering and Applied Chemistry CEAC Conférence Européenne de l'Aviation Civile (French: European Civil Aviation Conference) CEAC Compensatory Education Advisory Committee ) model, recently developed by NIST (National Institute of Standards & Technology, Washington, DC, www.nist.gov) The standards-defining agency of the U.S. government, formerly the National Bureau of Standards. It is one of three agencies that fall under the Technology Administration (www.technology. . The CEAC is a catalyst-mediated deposition model that successfully describes the filling of submicron features with copper, and is capable of predicting conditions that produce "wires" free of porosity and other defects. This understanding is key to creating the ever-finer multi-level copper interconnects of the future that are free of current-disrupting voids and seams. To extend and generalize the model, NIST scientists have studied silver deposition from silver-bearing electrolytes. The silver electrolyte with the addition of very low concentrations of selenium selenium (səlē`nēəm), nonmetallic chemical element; symbol Se; at. no. 34; at. wt. 78.96; m.p. 217°C;; b.p. about 685°C;; sp. gr. 4.81 at 20°C;; valence −2, +4, or +6. displays "brightening" and current-voltage hysteresis hysteresis (hĭs'tərē`sĭs), phenomenon in which the response of a physical system to an external influence depends not only on the present magnitude of that influence but also on the previous history of the system. similar to that observed in copper baths that exhibit excellent manufacturability. The selenium concentration on the evolving surface, analyzed by x-ray photoelectron spectroscopy X-ray Photoelectron Spectroscopy (XPS) is a quantitative spectroscopic surface chemical analysis technique used to estimate the empirical formula or elemental composition, chemical state and electronic state of the elements on the surface (upto 10 nm) of a material. as a function of deposition time, is found to track exactly with the acceleration of the silver deposition rate. Initial filling of submicron trenches and vias wit silver indicates good quality interconnects. The silver-based system offers several advantages over copper for developing a deposition model. First, the one-component additive, selenium, tat accelerates silver deposition is far simpler than the tree-component additive cocktail employed in copper deposition. Second, silver has a single valence in the electrolyte while copper is present in two valence states. The simplicity of the silver system will facilitate the quantification of surface coverage and its influence on silver deposition kinetics. This will make the study of metal deposition into submicron features far more straightforward, both analytically and computationally. CONTACT: Brett Baker, (301) 975-2245; brett.baker@nist.gov. |
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