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  Noble metal contacts for plating applicationsUSPTO Application #: 20060000708Title: Noble metal contacts for plating applications Abstract: Apparatus for electrochemical plating, comprising a support ring and a plurality of inwardly directed shanks extended from an inner circumference of the ring, wherein each of the shanks comprises a contacting tip brazed to the distal end the shank. (end of abstract) Agent: Patterson & Sheridan, LLP - Houston, TX, US Inventor: Harald Herchen USPTO Applicaton #: 20060000708 - Class: 204297010 (USPTO) Related Patent Categories: Chemistry: Electrical And Wave Energy, Apparatus, Electrolytic, Elements, Electrode Support Or Work Holder The Patent Description & Claims data below is from USPTO Patent Application 20060000708. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of co-pending U.S. patent application Ser. No. 10/349,761, filed on Jan. 22, 2002, entitled NOBLE METAL CONTACTS FOR PLATING APPLICATIONS. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention generally relates to semiconductor substrate processing systems. More specifically, the present invention relates to an apparatus for performing an electrochemical plating process in a semiconductor substrate processing system. [0004] 2. Description of the Related Art [0005] In ultra large scale integration integrated circuit (IC) devices (i.e., devices having more than one million logic gates), the multilevel interconnects are formed by filling the interconnect features (i.e., trenches, vias, and the like) with a metal, such as copper (Cu), aluminum (Al), and the like. Copper is the wiring material of choice in the interconnecting networks of advanced IC devices. In addition to superior electrical conductivity, copper is more resistant than aluminum (Al) to electromigration that, in operation, may destroy a thin film conductive line that carries an electrical current. [0006] As dimensions of the interconnect features decrease and the aspect ratios increase, a void-free metal fill using conventional metallizing techniques, such as chemical vapor deposition (CVD), physical vapor deposition (PVD), and the like, becomes increasingly difficult. As a result thereof, during manufacturing of advanced IC devices, electrochemical plating (ECP) has emerged as a production-worthy process for metallizing interconnect features. [0007] The ECP process is, generally, a two-step process. During a first step, a seed layer (e.g., copper seed layer) is formed upon the interconnect features, as well as elsewhere on the substrate. The seed layer may extend from a device surface (i.e., plating surface) of the substrate around the beveled edges to a backside (i.e., non-plating) surface of the substrate. Generally, the seed layer is deposited using a CVD, PVD, evaporation, and the like process. Then, during a second step, the substrate is exposed to a plating solution, while an electrical bias is simultaneously applied between the substrate and an anode electrode positioned within the plating solution. The plating solution is rich in ions of the metal to be plated onto the substrate (i.e., copper) and, as such, the electrical bias causes ions of such metal to be urged out of the plating solution and deposited onto the seed layer. [0008] The electrical bias is provided to the substrate using a plurality of electrical contacts. Typically, the same contacts are also used to provide a support to the substrate during the ECP process. Generally, such contacts are collectively bonded to a conductive support ring and engage the seed layer of the substrate. In operation, the electrical contacts apply a voltage to the seed layer, creating a current path through the plating solution. Such current path has an associated electrical resistance. The contacting surface of the tip of the electrical contact (i.e., portion of the contact having a contact with the seed layer) erodes as a result of exposure to the plating solution. Similarly, the resistance of the current path changes when a mechanical and electrical interface formed between the tip and a shank of the contact is degraded by the plating solution. [0009] In the prior art, to extend longevity of the electrical contacts, the contacting tip may be coated with a protective layer of noble metals, such as platinum (Pt), indium (In), and the like, or with a layer of an alloy of such metals. Generally, the contacting tip is attached to a shank of the contact using fasteners, such as screws and the like. Still, the electrical contacts of the prior art have limited service life and variable contact resistance, e.g., due to the thinness of the protective coating, deterioration of the interface between the tip and shank of the contact, and the like. The changes in the contact resistance of the electrical contact result in the non-uniformity of the film plated upon the substrate and may cause the ECP process to be defective. [0010] Therefore, there is a need in the art for an improved electrical contact that provides an electrical bias to a substrate during an electrochemical plating process. SUMMARY OF THE INVENTION [0011] The present invention is an apparatus for electrochemical plating, comprising a support ring having a plurality of inwardly directed shanks extended from an inner circumference of the ring, wherein each of the shanks comprises a contacting tip brazed to the distal end the shank. [0012] In one embodiment, the contacting tip is formed from a platinum/iridium alloy and is brazed to the shank using a palladium/cobalt alloy. In another embodiment, the shanks are formed from a metal, such as niobium (Nb), tantalum (Ta), and the like, that oxidizes in a plating solution and produces a protective oxide layer upon the shank. BRIEF DESCRIPTION OF THE DRAWINGS [0013] The teachings of the present invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which: [0014] FIG. 1 is a schematic, partial perspective and sectional view of an exemplary plating apparatus according to one application of the present invention; [0015] FIGS. 2A and 2B are, respectively, schematic, cross-sectional and top plan views of an exemplary support ring according to one embodiment of the present invention; [0016] FIGS. 3-5 are schematic, cross-sectional views of contacts of the support ring of FIGS. 2A, 2B according to embodiments of the present invention; and [0017] FIGS. 6A-6F illustrate an exemplary support ring at different steps of fabricating the contacts of FIG. 3 according to one embodiment of the present invention. [0018] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. [0019] It is to be noted, however, that the appended drawings illustrate only exemplary embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. DETAILED DESCRIPTION Continue reading... Full patent description for Noble metal contacts for plating applications Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Noble metal contacts for plating applications 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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