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  Methods of forming conductive materialsUSPTO Application #: 20060040414Title: Methods of forming conductive materials Abstract: The invention includes a method of forming a metal-comprising mass for a semiconductor construction. A semiconductor substrate is provided, and a metallo-organic precursor is provided proximate the substrate. The precursor is exposed to a reducing atmosphere to release metal from the precursor, and subsequently the released metal is deposited over the semiconductor substrate. The invention also includes capacitor constructions, and methods of forming capacitor constructions. (end of abstract)
Agent: Wells St. John P.s. - Spokane, WA, US Inventor: Haining Yang USPTO Applicaton #: 20060040414 - Class: 438003000 (USPTO) Related Patent Categories: Semiconductor Device Manufacturing: Process, Having Magnetic Or Ferroelectric Component The Patent Description & Claims data below is from USPTO Patent Application 20060040414. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATION [0001] This patent is a divisional of U.S. patent application Ser. No. 09/932,236, filed Aug. 16, 2001, entitled "Methods of Forming Metal-Comprising Materials and Capacitor Electrodes; and Capacitor Constructions"; the entirety of which is incorporated by reference herein. TECHNICAL FIELD [0002] The invention pertains to methods of forming metal-comprising materials, such as, for example, capacitor electrodes. The invention also pertains to capacitor constructions. BACKGROUND OF THE INVENTION [0003] Capacitor constructions are utilized in numerous semiconductor structures, such as, for example, memory arrays. An exemplary memory array is a dynamic random access memory (DRAM) array, with individual DRAM cells of the array comprising a capacitor and a transistor. [0004] Capacitor constructions comprise a first conductive capacitor electrode and a second conductive capacitor electrode, separated by a dielectric material. Among the compositions suitable for utilization as capacitor electrodes are metals, such as, for example, platinum, rhodium, iridium, ruthenium, etc. The metals can be deposited by exposing a metallo-organic precursor material to an oxidizing ambient (such as, for example, an ambient O.sub.2, O.sub.3, and/or N.sub.2O) to break down the precursor and release the metal. The released metal can then deposit on a substrate to form a metal film which is ultimately incorporated into a capacitor device as a capacitor electrode. [0005] A difficulty which can occur during oxidation of the metallo-organic precursors is that materials associated with a semiconductor substrate are exposed to the oxidizing conditions, and can themselves become oxidized or otherwise degraded during the degradation of the metallo-organic precursors. Accordingly, it would be desirable to develop alternative methods for formation of metallic materials on semiconductor substrates, other than the oxidation of metallo-organic precursors. SUMMARY OF THE INVENTION [0006] In one aspect, the invention encompasses a method of forming a metal-comprising mass for a semiconductor construction. A semiconductor substrate is provided, and a metallo-organic precursor is provided proximate the substrate. The precursor is exposed to a reducing atmosphere to release metal from the precursor, and subsequently the released metal is deposited over the semiconductor substrate. [0007] In another aspect, the invention encompasses an embodiment of forming a metal-comprising mass for a semiconductor construction wherein a metal-comprising precursor is exposed to ammonia to release metal from the precursor, and subsequently the release metal is deposited over a semiconductor substrate. [0008] In another aspect, the invention encompasses methodology for forming capacitor electrodes wherein a metal-comprising precursor is exposed to a reducing ambient to deposit a metal-comprising mass which ultimately is incorporated into a capacitor construction as a capacitor electrode. [0009] The invention also includes capacitor constructions. BRIEF DESCRIPTION OF THE DRAWINGS [0010] Preferred embodiments of the invention are described below with reference to the following accompanying drawing. [0011] The FIGURE is a diagrammatic, cross-sectional view of a semiconductor wafer fragment illustrating an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0012] An embodiment of the invention is described with reference to a semiconductor wafer fragment 10 in the figure. Fragment 10 includes a substrate 12, which can comprise, for example, monocrystalline silicon. To aid in interpretation of the claims that follow, the terms "semiconductive substrate" and "semiconductor substrate" are defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term "substrate" refers to any supporting structure, including, but not limited to, the semiconductive substrates described above. [0013] An insulative material 14 is formed over substrate 12, and can comprise, for example, borophosphosilicate glass (BPSG) and/or silicon dioxide. An opening extends through insulative material 14 and to substrate 12, and a diffusion region 16 is formed within substrate 12 at a base of such opening. Diffusion region 16 can be either n-type conductivity doped or p-type conductivity doped. Diffusion region 16 can be considered as an exemplary embodiment of an electrical node supported by substrate 12. [0014] A series of conductive materials are formed within the opening in mass 14, and extending above diffusion region 16. Such conductive materials include a mass 18 of conductively-doped silicon, such as, for example, n-type or p-type doped polycrystalline silicon. The conductive materials also include a layer 20 of metal silicide, and a layer 22 comprising metal or metal nitride. It is noted that other conductive materials can be used either alternatively, or in addition to the materials 18, 20 and 22 illustrated in the figure. For instance, material 18 can be replaced by a conductive metal plug, such as, for example, a titanium plug or a tungsten plug. In other embodiments, a layer of metal-silicide can be provided between diffusion region 16 and silicon-containing layer 18, with exemplary metal suicides comprising titanium silicide or tungsten silicide. Layers 18, 20 and 22 can be formed by conventional methods. [0015] In particular embodiments, layer 22 can comprise, consist of, or consist essentially of, one or more of titanium nitride, tungsten nitride, tantalum nitride, elemental titanium, elemental tantalum or elemental tungsten; and layer 20 can comprise, consist of, or consist essentially of, titanium silicide or tungsten silicide. Layers 20 and 22 function as diffusion and/or oxidation barriers. [0016] A metal-containing mass 24 is formed over conductive layer 22, and in the shown embodiment is in physical contact with layer 22. In accordance with methodology of the present invention, mass 24 is formed by exposing a metallo-organic precursor to a reducing atmosphere to release metal from the precursor, and subsequently the released metal is deposited to form mass 24. In the shown embodiment, mass 24 is patterned into a rectangular block. Such can be accomplished by, for example, photolithographic processing and an appropriate etch after deposition of the released metal. Appropriate photolithographic processing and etching conditions will be recognized by persons of ordinary skill in the art. [0017] Mass 24 can comprise, consist essentially of, or consist of one or more of ruthenium, rhodium, iridium, cobalt, palladium, nickel or platinum. In a particular embodiment, mass 24 will consist of, or consist essentially of, ruthenium, and will be formed by exposing tricarbonyl-cyclohexadiene ruthenium precursor to a reducing ambient comprising one or more of ammonia (NH.sub.3), diatomic hydrogen (H.sub.2), or plasma-activated hydrogen species. The reducing atmosphere can, in particular embodiments, consist of, or consist essentially of, one or more of ammonia, diatomic hydrogen or plasma-activated hydrogen species. In an exemplary embodiment, tricarbonyl-cyclohexadiene ruthenium precursor is exposed to ammonia at a temperature of 210.degree. C., and a pressure of 4 torr for a duration of 120 seconds, to deposit mass 24 to a thickness of about 450 .ANG.. [0018] Prior art methodologies have existed wherein a metal-containing mass is formed over a layer identical to the above-described layer 22 by exposing a metallo-organic material to oxidizing conditions. However, a problem with such prior art processes is that the oxidizing conditions can oxidize various components of layer 22 to reduce the conductivity of such layer. For instance, if layer 22 comprises titanium, tantalum or tungsten, the exposure of such layer to oxidizing conditions can form oxides of titanium, tungsten or tantalum. Such oxides are electrically insulative, and accordingly the desired conductive characteristics of layer 22 are compromised, or in some cases even entirely lost, which can render devices subsequently formed from layer 22 to be inoperable. In contrast, the utilization of reducing conditions in embodiments of the present invention can avoid oxidation of the materials of layer 22, and accordingly maintain the desired conductive characteristics of layer 22 during formation of mass 24. A further advantage of utilizing reducing conditions in methodology of the present invention is that many metallo-organic precursor materials contain oxygen, which can be released during chemical degradation of the precursor materials. The released oxygen can oxidize substrate materials. However, utilization of a reducing atmosphere can essentially scavenge the oxygen before it deleteriously reacts with a substrate material. For instance, in particular embodiments of the present invention, NH.sub.3 can be utilized to essentially scavenge oxygen. Continue reading... Full patent description for Methods of forming conductive materials Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Methods of forming conductive materials patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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