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  Contact ring with embedded flexible contactsUSPTO Application #: 20060237308Title: Contact ring with embedded flexible contacts Abstract: A contact assembly for supporting a substrate in an electrochemical plating system, wherein that contact assembly includes a contact ring and a thrust plate assembly. The contact ring includes an annular ring member having an upper surface and a lower surface, an annular bump member positioned on the upper surface, and a plurality of flexible and conductive substrate contact fingers extending radially inward from the lower surface. The thrust plate includes an annular plate member sized to be received within the annular ring member, and a seal member extending radially outward from the plate member, the seal member being configured to engage the annular bump member for form a fluid seal therewith. (end of abstract)
Agent: Patterson & Sheridan, LLP - Houston, TX, US Inventor: Harald Herchen USPTO Applicaton #: 20060237308 - 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 20060237308. 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. 10/355,479, filed Jan. 31, 2003, which is incorporated herein as reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] Embodiments of the invention generally relate to electrochemical plating and, more particularly, to a contact ring for an electrochemical plating system. [0004] 2. Description of the Related Art [0005] Metallization of sub-quarter micron sized features is a foundational technology for present and future generations of integrated circuit manufacturing processes. More particularly, in devices such as ultra large scale integration-type devices, i.e., devices having integrated circuits with more than a million logic gates, the multilevel interconnects that lie at the heart of these devices are generally formed by filling high aspect ratio (greater than about 4:1, for example) interconnect features with a conductive material, such as copper or aluminum, for example. Conventionally, deposition techniques such as chemical vapor deposition (CVD) and physical vapor deposition (PVD) have been used to fill these interconnect features. However, as the interconnect sizes decrease and aspect ratios increase, void-free interconnect feature fill via conventional metallization techniques becomes increasingly difficult. As a result thereof, plating techniques, such as electrochemical plating (ECP) and electroless plating, for example, have emerged as promising processes for void free filling of sub-quarter micron sized high aspect ratio interconnect features in integrated circuit manufacturing processes. [0006] In an ECP process, for example, sub-quarter micron sized high aspect ratio features formed into the surface of a substrate (or a layer-deposited thereon) may be efficiently filled with a conductive material, such as copper, for example. An ECP processes generally includes first depositing a seed layer over the surface and into features of the substrate (the seed layer deposition process is generally separate from the ECP plating process), and then the surface features of the substrate are exposed to an electrochemical plating solution, while an electrical bias is simultaneously applied between the substrate and an anode positioned in the plating solution. The plating solution is generally rich in positive ions to be plated onto the surface of the substrate, and therefore, the application of the electrical bias causes these positive ions to be urged out of the plating solution and to be plated onto the seed layer. [0007] Typically, the electrical bias is provided to the substrate via one or more electrical contacts distributed around the perimeter of the substrate being plated. Commonly, the seed layer formed on the substrate may extend from a plating surface around beveled edges of the substrate, and possibly extend onto a non-plating surface or backside of the substrate. Accordingly, for different systems, the electrical contacts may be in electrical contact with either the plating surface (frontside) or the non-plating surface (backside) of the substrate. Regardless of location, it is generally desirable to isolate the electrical contacts, as well as the non-plating surface of the substrate from the plating material in order to avoid plating of the positive ions on the contacts, as plating on the electrical contacts may alter the resistance of the electrical contacts and have a negative effect on the substrate plating uniformity. [0008] Conventional approaches to isolate the electrical contacts and non-plating surface from the plating solution typically include providing one or more sealing elements to contact the same surface of the substrate as the electrical contacts. For example, sealing members positioned to engage the plating surface may be placed adjacent electrical contacts positioned to contact the plating surface. The sealing members and electrical contacts also provide support for the substrate. However, the combination of the electrical contacts and the associated seals generally takes up several millimeters (generally between 3 and about 7 millimeters) of the perimeter of the plating surface area. Since this surface area is used to make electrical and seal contacts, the area cannot be used to support device formation. [0009] In an effort to utilize this perimeter surface area, some systems may include sealing members positioned to engage the non-plating surface adjacent electrical contacts positioned to contact the non-plating surface. However, without sealing members or electrical contacts on the plating surface to support the substrate, some other means may be needed to support the substrate. Typically, a vacuum is applied to the substrate, to pull the non-plating surface up into contact with the sealing members and electrical contacts. However, the vacuum applied to the substrate may create a stress on the substrate, and may lead to substrate breakage. If the sealing members happen to leak, the vacuum may be unable to maintain the substrate against the electrical contacts with sufficient force and the plating solution may enter the vacuum, causing damage to the vacuum. Further, in systems where the contact pins engage the plating surface of the substrate, the contact pins are generally surrounded by a seal configured to prevent the electroplating solution from coming into contact with the electrical contact pins. Although the concept of dry contact pins is noteworthy, there are several disadvantages of these configurations. Namely, dry contact configurations present challenges in maintaining a fluid tight seal between the substrate, and as such, fluid often penetrates the seals and is exposed to the contact pins, which alters the pin resistance and the plating uniformity. Additionally, conventional contact rings utilize fixed electrical contacts, and therefore, when a substrate being plated is not entirely planar, the various fixed contacts will have varying degrees of success contacting the substrate. [0010] Therefore, there is a need for an improved apparatus for securing a substrate in an electrochemical plating system. SUMMARY OF THE INVENTION [0011] Embodiments of the invention generally provide a contact assembly for supporting a substrate in an electrochemical plating system, wherein that contact assembly includes a contact ring and a thrust plate assembly. The contact ring includes an annular ring member having an upper surface and a lower surface, an annular bump member positioned on the upper surface, and a plurality of flexible and conductive substrate contact fingers extending radially inward from the lower surface. The thrust plate includes an annular plate member sized to be received within the annular ring member, and a seal member extending radially outward from the plate member, the seal member being configured to engage the annular bump member for form a fluid seal therewith. [0012] Embodiments of the invention further provide a contact ring for an electrochemical plating system. The contact ring generally includes an upper ring member, a lower ring member secured to the upper ring member via a plurality of support members, the lower ring member having an inwardly extending flange, a plurality of vertically flexible conductive contact pins extending radially inward from the lower ring member, an electrically insulating layer covering the plurality of the vertically flexible conductive contact pins, and a plurality of conductive tip members affixed to a terminating end of each of the plurality of vertically flexible conductive contact pins. [0013] Embodiments of the invention further provide a substrate contact assembly for an electrochemical plating system. The substrate contact assembly generally includes an electrically conductive contact ring, a first electrically insulating layer covering outer surfaces of the contact ring, a plurality of electrically conductive flexible contact fingers extending radially inward from the contact ring, and a second electrically insulating layer covering a body portion of the contact fingers, the second electrically insulating layer being configured to flex with the contact fingers while maintaining electrical isolation of the body portion. BRIEF DESCRIPTION OF THE DRAWINGS [0014] So that the manner in which the above recited features of the invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments thereof, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of the invention, and are therefore, not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. [0015] FIG. 1 illustrates a sectional view of an exemplary electrochemical plating cell incorporating an embodiment of a contact ring of the invention. [0016] FIG. 2 is a perspective view of an exemplary contact ring of the invention with a thrust plate positioned in contact with the contact ring. [0017] FIG. 3 is a sectional view of an exemplary contact ring of the invention. [0018] FIG. 4 is a plan view of an exemplary contact pin ring of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0019] Embodiments of the invention generally provide a contact ring configured to secure and electrically contacting a substrate in an electrochemical plating system. The contact ring generally includes a plurality of electrical contact pins radially positioned and configured to electrically contact a substrate being plated proximate the perimeter of the substrate. Further, although the contact pins are embedded within an insulative body, the contact pins are configured to be partially flexible and implemented in a wet contact configuration. Continue reading... Full patent description for Contact ring with embedded flexible contacts Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Contact ring with embedded flexible contacts 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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