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Passivative chemical mechanical polishing composition for copper film planarizationRelated Patent Categories: Compositions, Etching Or Brightening CompositionsPassivative chemical mechanical polishing composition for copper film planarization description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070181852, Passivative chemical mechanical polishing composition for copper film planarization. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATIONS [0001] This is a continuation of the U.S. patent application Ser. No. 10/315,641 for "Passivative Chemical Mechanical Polishing Composition for Copper Film Planarization" filed on Dec. 10, 2002 in the name of Jun Liu et al., which is incorporated herein in its entirety. FIELD OF THE INVENTION [0002] The present invention relates to a chemical mechanical polishing composition and to a method of using same for the polishing of semiconductor substrates having copper thereon, e.g., copper interconnects, electrodes, or metallization, as part of a semiconductor device structure on a wafer substrate. DESCRIPTION OF THE RELATED ART [0003] Copper is widely employed in semiconductor manufacturing as a material of construction for components of semiconductor device structures on wafer substrates (e.g., contacts, electrodes, conductive vias, field emitter base layers, etc.), and it is rapidly becoming the interconnect metal of choice in semiconductor manufacturing due to its higher conductivity and increased electromigration resistance relative to aluminum and aluminum alloys. [0004] Typically, the process scheme for utilizing copper in semiconductor manufacturing involves the damascene approach, wherein features are etched in a dielectric material. In the dual damascene process a single step is used to form both plugs and lines. Since copper has a propensity to diffuse into the dielectric material, leading to leakage between metal lines, barrier layers, such as Ta or TaN deposited by various deposition methods, are often used to seal the copper interconnects. Following deposition of the barrier layer material, a thin seed layer of copper is deposited on the barrier material via physical vapor deposition, followed by electrodeposition of copper to fill the features. The deposited copper must then be planarized to render it of suitable form to accommodate subsequent process steps in the fabrication of the finished semiconductor product, and in order to satisfactorily operate in the microcircuitry in which it is present. The planarization typically involves chemical mechanical polishing (CMP), using a CMP composition formulated for such purpose. [0005] Due to the difference in chemical reactivity between copper and the (Ta or TaN) barrier layer, two chemically distinct slurries are often used in the copper CMP process. The first step slurry (Step I) is used to rapidly planarize the topography and to uniformly remove the remaining copper, with the polish stopping at the barrier layer. The second step slurry (Step II) removes the barrier layer material at a high removal rate and stops on the dielectric oxide layer, or alternatively on a cap layer that has been applied to protect the oxide. [0006] Step I chemical mechanical polishing (CMP) compositions for planarization and polishing of copper typically are in the form of slurries containing an abrasive of suitable type, e.g., an abrasive selected from among silica, alumina, and other oxides and mineralic materials, in a solvent medium containing one or more solvent species, e.g., water, organic solvents, etc. [0007] One type of CMP composition for planarizing copper surfaces includes an aqueous slurry of abrasive particles, containing hydrogen peroxide as an oxidizing component and glycine as a chelating agent. Glycine has been found to react with solution phase Cu.sup.+2 ions formed by oxidation of Cu metal to form a Cu.sup.2+-glycine complex. The complexing of Cu.sup.+2 ions through formation of a water soluble Cu.sup.2+-glycine chelate assists in removal of Cu in protruded regions via a direct dissolution mechanism, and the Cu.sup.2+-glycine complex decomposes hydrogen peroxide to yield hydroxyl radicals having a higher oxidation potential than hydrogen peroxide itself. [0008] In step I CMP slurries containing abrasive particles, hydrogen peroxide and glycine, the compound benzotriazole (BTA) is often used as a corrosion inhibitor. BTA FW: 119.13) complexes with copper to form an insoluble Cu-BTA complex on the copper surface. The resulting insoluble protective film facilitates the planarization of the topography of the device structure being fabricated, since the recessed areas on the wafer surface are protected from dissolution, while mechanical action of the abrasive species on the protruding areas enables material removal and polishing to be carried out. Additionally, the Cu-BTA complex minimizes corrosion and preserves the functional integrity of the copper device structures for their intended use. [0009] BTA functions well as a copper corrosion inhibitor in the absence of OH radicals generated as a result of the Cu.sup.2+-glycine induced catalytic decomposition of hydrogen peroxide. However, in first step copper CMP slurries containing hydrogen peroxide and glycine, the formation of highly oxidizing OH radicals under dynamic CMP conditions cannot be avoided, since copper metal is readily oxidized in such CMP environment. [0010] Experiments with the addition of Cu.sup.2+ to an H.sub.2O.sub.2/glycine/BTA system have shown that the presence of Cu.sup.2+ increases the static etch rate of Cu dramatically, and at the same time, the Cu corrosion potential is shifted to less noble ranges. [0011] The significance of this finding is that BTA is not effective in protecting the low features of copper wafer surfaces during the CMP process, and thus allows "dishing" to occur in high-density patterned areas when Cu.sup.2+ cation is present in the CMP composition. [0012] An alternative to the use of BTA as a corrosion inhibitor in CMP compositions therefore is highly desirable. Specifically, an alternative corrosion inhibitor is desired, which is compatible with H.sub.2O.sub.2/glycine-based CMP compositions and effective to passivate copper surfaces when significant amounts of Cu ions are present in bulk solution and/or near the metal/solution interface during CMP processing. SUMMARY OF THE INVENTION [0013] The present invention relates to CMP compositions containing 5-aminotetrazole (ATA, FW: 85.06), and to copper CMP using such compositions. [0014] In one aspect, the invention relates to a CMP composition for planarization of copper films, in which the composition includes oxidizing agent, chelating agent, and corrosion inhibitor, and the corrosion inhibitor includes 5-aminotetrazole. [0015] In a further aspect, the invention relates to a CMP composition for planarization of copper films. The composition comprises an aqueous slurry medium including abrasive, solvent, ATA, H.sub.2O.sub.2 and glycine. In the composition, ATA, H.sub.2O.sub.2 and glycine have the following concentrations by weight, based on the total weight of the composition: TABLE-US-00001 ATA 0.01-10 wt. % H.sub.2O.sub.2 1-30 wt. % Glycine 0.1-25 wt. %. [0016] Yet another aspect of the invention relates to a CMP composition including the following components by weight, based on the total weight of the composition: TABLE-US-00002 ATA 0.01-10 wt. % H.sub.2O.sub.2 1-30 wt. % Glycine 0.1-25 wt. %. Abrasive 0-30 wt. % Water 30-90 wt. % with the total wt. % of all components in the composition totaling to 100 wt. %. [0017] Still another aspect of the invention relates to a method of polishing copper on a substrate having copper thereon, including contacting copper on the substrate under CMP conditions with a CMP composition effective for polishing the copper, wherein the CMP composition includes ATA. [0018] Other aspects, features and embodiments of the invention will be more fully apparent from the ensuing disclosure and appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Continue reading about Passivative chemical mechanical polishing composition for copper film planarization... 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