EP1697989A2 - Connecteur permettant d'etablir un contact electrique a des echelles de semi-conducteurs et procede de formation associe - Google Patents

Connecteur permettant d'etablir un contact electrique a des echelles de semi-conducteurs et procede de formation associe

Info

Publication number
EP1697989A2
EP1697989A2 EP04813215A EP04813215A EP1697989A2 EP 1697989 A2 EP1697989 A2 EP 1697989A2 EP 04813215 A EP04813215 A EP 04813215A EP 04813215 A EP04813215 A EP 04813215A EP 1697989 A2 EP1697989 A2 EP 1697989A2
Authority
EP
European Patent Office
Prior art keywords
contact
connector
contact element
substrate
curved spring
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP04813215A
Other languages
German (de)
English (en)
Inventor
Dirk D. Brown
John D. Williams
Eric M. Radza
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Neoconix Inc
Original Assignee
Neoconix Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/731,213 external-priority patent/US20050120553A1/en
Priority claimed from US10/731,669 external-priority patent/US7244125B2/en
Application filed by Neoconix Inc filed Critical Neoconix Inc
Publication of EP1697989A2 publication Critical patent/EP1697989A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/71—Means for bonding not being attached to, or not being formed on, the surface to be connected
    • H01L24/72—Detachable connecting means consisting of mechanical auxiliary parts connecting the device, e.g. pressure contacts using springs or clips
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
    • G01R1/02—General constructional details
    • G01R1/06—Measuring leads; Measuring probes
    • G01R1/067—Measuring probes
    • G01R1/06711—Probe needles; Cantilever beams; "Bump" contacts; Replaceable probe pins
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
    • G01R1/02—General constructional details
    • G01R1/06—Measuring leads; Measuring probes
    • G01R1/067—Measuring probes
    • G01R1/073—Multiple probes
    • G01R1/07307—Multiple probes with individual probe elements, e.g. needles, cantilever beams or bump contacts, fixed in relation to each other, e.g. bed of nails fixture or probe card
    • G01R1/07342—Multiple probes with individual probe elements, e.g. needles, cantilever beams or bump contacts, fixed in relation to each other, e.g. bed of nails fixture or probe card the body of the probe being at an angle other than perpendicular to test object, e.g. probe card
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R12/00—Structural associations of a plurality of mutually-insulated electrical connecting elements, specially adapted for printed circuits, e.g. printed circuit boards [PCB], flat or ribbon cables, or like generally planar structures, e.g. terminal strips, terminal blocks; Coupling devices specially adapted for printed circuits, flat or ribbon cables, or like generally planar structures; Terminals specially adapted for contact with, or insertion into, printed circuits, flat or ribbon cables, or like generally planar structures
    • H01R12/50—Fixed connections
    • H01R12/51—Fixed connections for rigid printed circuits or like structures
    • H01R12/52—Fixed connections for rigid printed circuits or like structures connecting to other rigid printed circuits or like structures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R12/00—Structural associations of a plurality of mutually-insulated electrical connecting elements, specially adapted for printed circuits, e.g. printed circuit boards [PCB], flat or ribbon cables, or like generally planar structures, e.g. terminal strips, terminal blocks; Coupling devices specially adapted for printed circuits, flat or ribbon cables, or like generally planar structures; Terminals specially adapted for contact with, or insertion into, printed circuits, flat or ribbon cables, or like generally planar structures
    • H01R12/70—Coupling devices
    • H01R12/71—Coupling devices for rigid printing circuits or like structures
    • H01R12/712—Coupling devices for rigid printing circuits or like structures co-operating with the surface of the printed circuit or with a coupling device exclusively provided on the surface of the printed circuit
    • H01R12/714—Coupling devices for rigid printing circuits or like structures co-operating with the surface of the printed circuit or with a coupling device exclusively provided on the surface of the printed circuit with contacts abutting directly the printed circuit; Button contacts therefore provided on the printed circuit
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    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/02—Contact members
    • H01R13/03—Contact members characterised by the material, e.g. plating, or coating materials
    • H—ELECTRICITY
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    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/02—Contact members
    • H01R13/22—Contacts for co-operating by abutting
    • H01R13/24—Contacts for co-operating by abutting resilient; resiliently-mounted
    • H01R13/2407—Contacts for co-operating by abutting resilient; resiliently-mounted characterized by the resilient means
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    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/02—Contact members
    • H01R13/22—Contacts for co-operating by abutting
    • H01R13/24—Contacts for co-operating by abutting resilient; resiliently-mounted
    • H01R13/2464—Contacts for co-operating by abutting resilient; resiliently-mounted characterized by the contact point
    • H01R13/2492—Contacts for co-operating by abutting resilient; resiliently-mounted characterized by the contact point multiple contact points
    • H—ELECTRICITY
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    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R43/00—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors
    • H01R43/007—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors for elastomeric connecting elements
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
    • H05K3/4092—Integral conductive tabs, i.e. conductive parts partly detached from the substrate
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00—Constructional details common to different types of electric apparatus
    • H05K7/02—Arrangements of circuit components or wiring on supporting structure
    • H05K7/10—Plug-in assemblages of components, e.g. IC sockets
    • H05K7/1053—Plug-in assemblages of components, e.g. IC sockets having interior leads
    • H05K7/1061—Plug-in assemblages of components, e.g. IC sockets having interior leads co-operating by abutting
    • H05K7/1069—Plug-in assemblages of components, e.g. IC sockets having interior leads co-operating by abutting with spring contact pieces
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R3/00—Apparatus or processes specially adapted for the manufacture or maintenance of measuring instruments, e.g. of probe tips
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    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
    • H01L2224/45138—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
    • H01L2224/45144—Gold (Au) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
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    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/32—Holders for supporting the complete device in operation, i.e. detachable fixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/42—Wire connectors; Manufacturing methods related thereto
    • H01L24/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L24/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
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    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/00014—Technical content checked by a classifier the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
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    • H01R43/00—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors
    • H01R43/20—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors for assembling or disassembling contact members with insulating base, case or sleeve
    • H01R43/205—Apparatus or processes specially adapted for manufacturing, assembling, maintaining, or repairing of line connectors or current collectors or for joining electric conductors for assembling or disassembling contact members with insulating base, case or sleeve with a panel or printed circuit board
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/325—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by abutting or pinching, i.e. without alloying process; mechanical auxiliary parts therefor
    • H05K3/326—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by abutting or pinching, i.e. without alloying process; mechanical auxiliary parts therefor the printed circuit having integral resilient or deformable parts, e.g. tabs or parts of flexible circuits

Definitions

  • the invention relates to reconnectable, remountable electrical connectors, and, in particular, to an electrical connector for connecting to semiconductor scale devices. DESCRIPTION OF THE RELATED ART
  • Electrical interconnects or connectors are used to connect two or more electronic components together or to connect an electronic component to a piece of electrical equipment, such as a computer, router, or tester.
  • an electrical interconnect is used to connect an electronic component, such as an integrated circuit (an IC or a chip), to a printed circuit broad.
  • An electrical interconnect is also used during integrated circuit manufacturing for connecting an IC device under test to a test system.
  • the electrical interconnect or connector provides separable or remountable connection so that the electronic component attached thereto can be removed and reattached. For example, it may be desirable to mount a packaged microprocessor chip to a personal computer mother board using a separable interconnect device so that malfunctioning chips can be readily removed or upgraded chips can be readily installed.
  • an electrical connector is used to make direct electrical connection to metal pads fo ⁇ ned on a silicon wafer.
  • Such an electrical connector is often refe ⁇ ed to as a "probe” or “probe card” and is typically used during the testing of the wafer during the manufacturing process.
  • the probe card typically mounted on a tester, provides electrical connection from the tester to the silicon wafer so that individual integrated circuits formed on the wafer can be tested for functionality and compliance with specific parametric limits.
  • Conventional electrical connectors are usually made of stamped metal springs, which are formed and then individually inserted into an insulating ca ⁇ ier to form an anay of electrical connection elements.
  • Other approaches to making electrical connectors include using isotropically conductive adhesives, injection molded conductive adhesives, bundled wire conductive elements, springs fo ⁇ ned by wirebonding techniques, and small solid pieces of metal.
  • Land grid anay refers to an anay of metal pads (also called lands) that are used as the electrical contact points for an integrated circuit package, a printed circuit board, or other electronic component.
  • the metal pads are usually fo ⁇ ned using thin film deposition techniques and coated with gold to provide a non-oxidizing surface.
  • Ball Grid array refers to an anay of solder balls or solder bumps that are used as the electrical contact points for an integrated circuit package. Both LGA and BGA packages are widely used in the semiconductor industry and each has its associated advantages or disadvantages. For instance, LGA packages are typically cheaper to manufacture than ball grid anay (BGA) packages because there is no need to form solder balls or solder bumps.
  • LGA packages are typically more difficult to assemble onto a PC board or a multi-chip module.
  • An LGA connector is usually used to provide removable and remountable socketing capability for LGA packages connected to PC boards or to chip modules.
  • the pitch that is, the spacing between each electrical contact point (also refe ⁇ ed to as a "lead") on a semiconductor device is decreasing dramatically in certain applications. For example, contact pads on a semiconductor wafer can have a pitch of 250 micron or less.
  • a connector 10 includes a contact element 12 for making electrical connection to a metal pad 16 on a substrate 14.
  • Connector 10 can be a wafer probe card and contact element 12 is then a probe tip for engaging pad 16 on silicon substrate 14.
  • contact element 12 engages metal pad 16 contact element must pierce through film 18 in order to make a reliable electrical connection to metal pad 16.
  • the piercing of film 18 can be resulted from a wiping action or a piercing action of contact element 12 when the contact element engages the metal pad.
  • FIG. 2A illustrates a contact element being applied to contact a solder ball.
  • contact element 12 contacts solder ball 22 fo ⁇ ned on a substrate 20 such as for testing, contact element 12 applies a piercing action which often result in the formation of a crater on the top surface (also called the base surface) of the solder ball.
  • substrate 20 including solder ball 22 is subsequently attached to another semiconductor device, such as a PC board or a chip-scale package, the crater in solder ball 22 can lead to void formation at the solder ball interface.
  • Figures 2B and 2C illustrate the result of attaching solder ball 22 to a metal pad 26 of a substrate 24. After solder reflow (Figure 2C), solder ball 22 is attached to metal pad 26. However, a void is formed at the solder ball interface due to the presence of the crater on the top surface of solder ball 22 which crater was created by the piercing action of contact element 12. The presence of such a void can affect the electrical characteristics of the connection and more importantly, degrades the reliability of the connection.
  • an electrical contact element that can be provide a controlled wiping action on a metal pad, particularly for pads with a pitch of less than 50 microns. It is also desirable that the wiping action provides a wiping distance of up to 50% of the contact pad. Furthermore, when electrical contact to solder balls are made, it is desirable to have an electrical contact element that can provide a controlled wiping action on the solder ball without damaging the contact surface of the solder ball. [0011] Another problem encountered by electrical connectors is the variation in coplanarity and positional misalignment of the contact points of a semiconductor device to be connected.
  • United States Patent No. 6, 184,065, issued to Smith et al. on February 6, 2001 discloses small metal springs created by the inherent stress gradient in a thin metal film. Smith's approach provides an anay of all-metal contacts at semiconductor scales. However, the metal springs point into the surface of the plane to be contacted and therefore is prone to damaging the solder balls when used to probe solder balls.
  • United States Patent No. 6,250,933 issued to Khoury et al. on June 26, 2001, discloses a contact structure in which the contactors are produced on a semiconductor substrate or other dielectric by microfabrication technology and in which each of the contactors is shaped like a bridge, with one or more angled portions supporting a horizontal contacting portion.
  • Khoury' s approach provides an anay of all-metal contacts at semiconductor scales but provides a limited amount of wiping action when interfacing with metal pads because the contacting component is parallel to the metal pad.
  • Khoury addresses the lack of wiping problem by adding asperities and making asymmetric structures to induce a wiping action.
  • a connector for electrically connecting to pads formed on a semiconductor device includes a substrate and an anay of contact elements of conductive material fo ⁇ ned on the substrate.
  • Each contact element includes a base portion attached to the top surface of the substrate and a curved spring portion extending from the base portion and having a distal end projecting above the substrate.
  • the curved spring portion is fo ⁇ ned to curve away from a plane of contact and has a curvature disposed to provide a controlled wiping action when engaging a respective pad of the semiconductor device.
  • a method for forming a connector including an anay of contact elements includes providing a substrate, forming a support layer on the substrate, patterning the support layer to define an anay of support elements, isotropically etching the anay of support elements to form rounded corners on the top of each support element, forming a metal layer on the substrate and on the anay of support elements, and patterning the metal layer to define an anay of contact elements where each contact element includes a first metal portion on the substrate and a second metal portion extending from the first metal portion and partially across the top of a respective support element.
  • the method further includes removing the anay of support elements.
  • the anay of contact elements thus fo ⁇ ned each includes a base portion attached to the substrate and a curved spring portion extending from the base portion and having a distal end projecting above the substrate.
  • the curved spring portion is formed to have a concave curvature with respect to the surface of the substrate.
  • a method for forming a connector including an anay of contact elements includes providing a substrate, providing a conductive adhesion layer on the substrate, forming a support layer on the conductive adhesion layer, patterning the support layer to define an anay support elements, isotropically etching the anay of support elements to form rounded corners on the top of each support element, forming a metal layer on the conductive adhesion layer and on the anay of support elements, patterning the metal layer and the conductive adhesion layer to define an anay of contact elements.
  • Each contact element includes a first metal portion formed on a conductive adhesion portion and a second metal portion extending from the first metal portion and partially across the top of a respective support element.
  • the method further includes removing the anay of support elements.
  • the anay of contact elements thus formed each includes a base portion attached to the conductive adhesion portion which is attached to the substrate and a curved spring portion extending from the base portion and having a distal end projecting above the substrate.
  • the curved spring portion is formed to have a concave curvature with respect to the surface of the substrate.
  • Figure 1 illustrates a contact element being applied to engage a metal pad on a substrate.
  • Figure 2 A illustrates a contact element being applied to contact a solder ball.
  • Figures 2B and 2C illustrate the result of attaching a damaged solder ball to a metal pad of a substrate.
  • Figures 3 A and 3B are cross-sectional view of a connector according to one embodiment of the present invention.
  • Figures 4A and 4B are cross-sectional diagrams illustrating the use of the connector of Figure 3 A for engaging different semiconductor devices.
  • Figures 5 A and 5B illustrate a connector according to an alternate embodiment of the present invention.
  • Figures 6 A and 6B illustrate connectors according to alternate embodiments of the present invention.
  • Figures 7 A to 7H illustrate the processing steps for forming the connector of
  • FIG. 3 A according to one embodiment of the present invention.
  • FIGS. 8A to 8H illustrate the processing steps for forming the connector of
  • FIG. 5 A according to one embodiment of the present invention.
  • Figures 9 A to 9H illustrate the processing steps for forming the connector of
  • Figure 5 A according to an alternate embodiment of the present invention.
  • Figures 10 A and 10B are cross-sectional views of a connector according to an alternate embodiment of the present invention.
  • Figure 11 is a cross-sectional view of a connector including a ground plane for improving signal integrity and for controlling contact element impedance according to one embodiment of the present invention.
  • Figure 12 illustrates another embodiment of the connector of the present invention where a pair of contact elements is used to couple to a pair of differential signals.
  • Figure 13 illustrates a connector incorporating a thermally conductive plane according to one embodiment of the present invention.
  • Figure 14 is a cross-sectional view of a connector including a coaxial contact element according to one embodiment of the present invention.
  • FIGS 15 A to 15H illustrate the processing steps for forming an anay of connectors according to an alternate embodiment of the present invention.
  • DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0037]
  • a connector for providing separable and remountable connection to a device includes an anay of contact elements fo ⁇ ned on a substrate where each contact element includes a curved spring portion formed to curve away from a plane of contact and having a curvature disposed to provide a controlled wiping action when engaging a contact point of the device.
  • the connector of the present invention can be used to make electrical connection to devices at semiconductor scales, such as a silicon wafer or a packaged integrated circuit.
  • the contact elements can be formed to make electrical connection to contact points having a pitch of 250 micron or less and in particular, the contact elements of the present invention enable electrical connection to contact points having a pitch of 50 micron or less.
  • the connector of the present invention can be used to connect to a variety of contact surfaces without damaging the contact surface.
  • the contact elements in the connector of the present invention have a large elastic working range approximately equal to or greater than the electrical path length, thereby allowing the contact elements to operate over a large range of compressions often required in normal operating conditions.
  • the connector of the present invention provides numerous advantages over conventional connector systems.
  • the connector of the present invention includes contact elements having a curved spring portion that curved away from the plane of contact, that is, the surface of the contact points to be contacted.
  • the contact elements can provide a soft controlled wiping action when engaging a metal pad or a solder ball, allowing effective electrical connection to be made without damaging the contact surface.
  • the contact elements in the connector of the present invention can achieve an optimal wiping distance with optimal contact force.
  • Conventional connectors often include curved spring members that curved into the plane of contact. Such curvature results in a piercing action when the spring members are engaged with a contact pad and often results in undesirable damages to the pad.
  • the contact element either provides no wiping action or insufficient wiping distance.
  • the connector of the present invention overcomes many of the disadvantages of the conventional connectors.
  • the connector of the present invention provides scalable, low profile, low insertion force, high density, and separable/reconnectable electrical connection and is particularly suited for use in high speed and high performance applications.
  • the connector can be built at relatively low cost while exhibiting highly reliable and compliant operating characteristics.
  • the connector of the present invention can be scaled to contact metal pads on a wafer or lands of a LGA package where the pads or lands are separated by a pitch of 50 microns or less.
  • the connector of the present invention can also be scaled to contact solder balls of a BGA package or solder balls formed on a wafer where the solder balls are separated by a pitch of 250 micron or less.
  • the connector of the present invention can be used to engage pads of semiconductor device which pads are in vertical alignment with the contact elements of the connection. Thus, only the application of a vertical external biasing force is needed to connect the connector to the device to be connected. This is in contrary to many conventional connector systems which require the application of a lateral force to engage a connector and often result in damage to the connection points.
  • the connector of the present invention can be used to make electrical connection to a wide variety of devices.
  • the connector of the present invention can be used to make electrical connection to metal pads on a silicon wafer, to a ball grid anay (BGA) package, to a land grid anay package, to a wafer-level package, to a chip scale package and other semiconductor or electrical device.
  • BGA ball grid anay
  • a semiconductor device can include but is not limited to a semiconductor wafer, a packaged or unpackaged integrated circuit (IC), a ball grid anay formed on a semiconductor wafer or as an IC package, a land grid anay formed on a semiconductor wafer, on a chip module or on an IC package.
  • IC integrated circuit
  • Figures 3 A and 3B are cross-sectional view of a connector according to one embodiment of the present invention.
  • Figures 3 A and 3B illustrate a connector 50 of the present invention being connected to a semiconductor device 60 including metal pads 64, formed on a substrate 62, as contact points.
  • Semiconductor device 60 can be a silicon wafer where metal pads 64 are the metal bonding pads formed on the wafer.
  • Semiconductor device 60 can also be a LGA package where metal pads 64 represent the "lands" or metal connection pads formed on the LGA package.
  • the coupling of connector 50 to semiconductor device 60 in Figures 3A and 3B is illustrative only and is not intended to limit the application of connector 50 to connecting with wafers or LGA packages only.
  • connector 50 includes an anay of contact elements 54 formed on a substrate 52.
  • Substrate 52 can be formed as a dielectric material or a semiconductor material. Because connector 50 can be built be for connecting to semiconductor devices at semiconductor scales, connector 50 is usually formed using material that are commonly used in semiconductor fabrication processes.
  • substrate 52 is made of quartz, silicon or a ceramic wafer and contact elements 54 are formed on a dielectric layer which dielectric layer could be a SOS, SOG, BPTEOS, or TEOS layer formed on the top surface of the substrate.
  • the anay of contact elements is typically formed as a two-dimensional anay ananged to mate with conesponding contact points on a semiconductor device to be contacted.
  • connector 50 is formed to contact metal pads having a pitch of 50 microns or less.
  • Contact elements 54 are formed using a conductive material. Each contact element 54 includes a base portion 55A attached to the top surface of substrate 52 and a curved spring portion 55B extending from base portion 55A. Curved spring portion 55B has a proximal end contiguous with base portion 55 A and a distal end projecting above substrate 52. Note that Figures 3A and 3B illustrate connector 50 being turned upside down to engage semiconductor device 60.
  • the use of directional terms such as "above” and "top surface” in the present description is intended to describe the positional relationship of the elements of the connector as if the connector is positioned with the contact elements facing upward.
  • the directional terms used herein are illustrative only and intended only to describe the relative position of different parts of the contact element.
  • contact element 54 includes curved spring portion that is formed to curve away from a plane of contact.
  • the "plane of contact” refers to the surface of the contact point to which the contact element is to be contacted.
  • the plane of contact is the surface of metal pad 64.
  • curved spring portion 55B is formed to have a concave curvature with respect to the surface of substrate 52.
  • curved spring portion 55B curves away from the surface of metal pad 64.
  • Curved spring portion 55B of contact element 54 has a curvature that is disposed to provide a controlled wiping action when engaging a respective metal pad 64 of the semiconductor device to be contacted.
  • an external biasing force denoted F in Figure 3 A
  • F an external biasing force
  • the curved spring portion of a contact element 54 engages the respective metal pad in a controlled wiping action so that each contact element makes effective electrical connection to the respective pad.
  • the curvature of contact elements 54 ensures that the optimal contact force is achieved concunently with the optimal wiping distance.
  • the wiping distance is the amount of travel the distal end of the contact element makes on the surface of the metal pad when contacting the metal pad.
  • the contact force can be on the order of 5 to 100 grams depending on the application and the wiping distance can be on the order of 5 to 400 microns.
  • the contact element of the present invention enables a very large elastic working range. Specifically, because the curved spring portion can move in both the vertical and the horizontal directions, an elastic working range on the order of the electrical path length of the contact element can be achieved.
  • the "electrical path length" of the contact element is defined as the distance the electrical cu ⁇ ent has to travel from the distal end of the curved spring portion to the base portion of the contact element.
  • the contact elements of the connector of the present invention have an elastic working range that spans the entire length of the contact elements.
  • Contact elements 54 are formed using a conductive metal that can also provide the desired elasticity.
  • contact elements 54 are formed using titanium (Ti) as a support structure that can later be plated to obtain desired elastic behavior.
  • contact elements 54 are formed using a copper-alloy (Cu-alloy) or a multilayer metal sheet such as stainless steel coated with Copper-Nickel-Gold (Cu/Ni/Au) multilayer metal sheet.
  • the contact elements are formed using a small- grained copper-beryllium (CuBe) alloy and then plated with electroless Nickel-Gold (Ni/Au) to provide a non-oxidizing surface.
  • contact elements 54 are formed using different metals for the base portions and the curved spring portions.
  • contact element 54 is shown as formed by a rectangular shaped based portion with one curved spring portion.
  • This configuration is illustrative only and is not intended to be limiting.
  • the contact element of the present invention can be formed in a variety of configurations and each contact element only needs to have a base portion sufficient for attaching the curved spring portion to the substrate.
  • the base portion can assume any shape and can be formed as a circle or other useful shape for attaching the contact element to the substrate.
  • a contact element can include multiple curved spring portions extended from the base portion as will be discussed in more detail below.
  • FIGS 4A and 4B are cross-sectional diagrams illustrating the use of connector 50 for engaging different semiconductor devices.
  • positional variations of the metal pads to be contacted require contact elements at one end of connector 50 to be more compressed than contact elements at the opposite end.
  • coplanarity variations of the metal pads to be contacted require contact elements in the middle portion of connector 50 to be more compressed than contact elements at the two ends of connector 50.
  • FIGs 5 A and 5B illustrate a connector according to an alternate embodiment of the present invention.
  • a connector 70 includes an anay of contact elements 74 formed on substrate 72.
  • each contact element 74 includes a base portion 75A and two curved spring portions 75B and 75C extending from base portion 75 A.
  • Curved spring portion 75B and 75C have distal ends projecting above substrate 72 and facing towards each other.
  • Other characteristics of curved spring portions 75B and 75C are the same as curved spring portion 55B.
  • curved spring portions 75B and 75C are fo ⁇ ned curved away from a plane of contact and each has a curvature disposed to provide a controlled wiping action when engaging a contact point of a semiconductor device to be contacted. Furthermore, curved spring portions 75B and 75C have an elastic working range approximately equal to the electrical path length of the contact element, thus enabling a large range of compression to be applied.
  • connector 70 is used to contact a semiconductor device 80, such as a BGA package, including an anay of solder balls 84 as contact points.
  • Figure 5B illustrates connector 70 being fully engaged with semiconductor device 80.
  • Connector 70 can be used to contact metal pads such as pads on a land grid anay package.
  • using of connector 70 to contact solder balls 84 provides particular advantages.
  • contact elements 74 contact the respective solder balls along the side of the solder balls. No contact to the base surface of the solder ball is made. Thus, contact elements 74 do not damage the base surface of the solder balls during contact and effectively elimination the possibility of void formation when the solder balls are subsequently reflowed for permanently attachment.
  • each curved spring portion of contact elements 74 is formed to curved away from the plane of contact which in the present case is a plane tangent to the side surface of the solder ball being contacted, the contact elements 74 provides a controlled wiping action when making contact with the respective solder balls. In this manner, effective electrical connection can be made without damaging the contact surface, that is, the surface of the solder balls.
  • connector 70 is scalable and can be used to contact solder balls having a pitch of 250 microns or less.
  • each contact element has a large elastic working range on the order of the electrical path length, the contact elements can accommodate a large range of compression. Therefore, the connector of the present invention can be used effectively to contact conventional devices having normal coplanarity variations or positional misalignments.
  • Connectors 50 and 70 in Figures 3 A and 5A are shown as including a curved spring portion that projects linearly from the base portion. The embodiments shown in Figures 3A and 5A are illustrative only and are not intended to be limited.
  • the connector of the present invention can be configured in a variety manner depending on the types of contact points to be contacted and depending on the desired contact force.
  • Figures 6A and 6B illustrate connectors according to alternate embodiments of the present invention.
  • a connector 90 includes a contact element 93 formed on a substrate 92.
  • Contact element 93 includes a base portion 94A and a first curved spring portion 94B and a second curved spring portion 94C.
  • First curved spring portion 94B and second curved spring portion 94C have distal ends that point away from each other.
  • Contact element 93 can be used to engage a contact point including a metal pad or a solder ball. When used to engage a solder ball, contact element 93 cradles the solder ball between the first and second curved spring portions.
  • first and second curved spring portions 94B and 94C contact the side surface of the solder ball in a controlled wiping motion in a direction that curved away from the plane of contact of the solder ball.
  • Figure 6B illustrates a contact element 95 fo ⁇ ned on a substrate 96.
  • Contact element 95 includes a base portion 97A and a first curved spring portion 97B and a second curved spring portion 97C extended from the base portion.
  • first curved spring portion 97B and the second curved spring portion 97C project above substrate 96 in a spiral configuration.
  • Contact element 95 can be used to contact a metal pad or a solder ball.
  • first and second curved spring portion 97B and 97C curve away from the plane of contact and provide a controlled wiping action.
  • the connectors of the present invention can be manufactured in a variety of processes using different processing sequence.
  • the curved spring portion of each contact element can be formed by stamping.
  • the connectors of the present invention are formed using semiconductor processing techniques.
  • the connectors of the present invention can be refened to as being built as MicroElectroMechanical Systems (MEMS).
  • MEMS MicroElectroMechanical Systems
  • the connector of the present invention is also refened to as a MEMS grid anay connector.
  • Figures 7A to 7H illustrate the processing steps for forming connector 50 of
  • a substrate 102 on which the contact elements are to be formed is provided.
  • Substrate 102 can be a silicon wafer or ceramic wafer for example and may include a dielectric layer formed thereon (not shown in Figure 7A).
  • a dielectric layer of SOS, SOG, BPTEOS, or TEOS layer can be formed on substrate 102 for isolating the contact elements from substrate 102.
  • a support layer 104 is formed on substrate 102.
  • Support layer 104 can be a deposited dielectric layer, such as an oxide or nitride layer, a spin-on dielectric, a polymer, or any other suitable etchable material.
  • support layer 104 is deposited by a chemical vapor deposition (CVD) process. In another embodiment, support layer 104 is deposited by a plasma vapor deposition (PVD) process. In yet another embodiment, support layer 104 is deposited by a spin-on process. In yet another embodiment, when substrate 102 is not covered by a dielectric layer or a conductive adhesive layer, the support layer can be grown using an oxidation process commonly used in semiconductor manufacturing.
  • CVD chemical vapor deposition
  • PVD plasma vapor deposition
  • spin-on process when substrate 102 is not covered by a dielectric layer or a conductive adhesive layer, the support layer can be grown using an oxidation process commonly used in semiconductor manufacturing.
  • a mask layer 106 is formed on the top surface of support layer 104.
  • Mask layer 106 is used in conjunction with a conventional lithography process to define a pattern on support layer 104 using mask layer 106.
  • a mask pattern including regions 106 A to 106C, is fo ⁇ ned on the surface of support layer 104 defining areas of support layer 104 to be protected from subsequent etching.
  • an anisotropic etching process is performed using regions 106A to 106C as a mask.
  • support layer 104 not covered by a patterned mask layer is removed. Accordingly, support regions 104A to 104C are formed.
  • the mask pattern including regions 106 A to 106C is subsequently removed to expose the support regions ( Figure 7D).
  • support regions 104A to 104C are then subj ected to an isotropic etching process.
  • An isotropic etching process remove material under etch in the vertical and horizontal directions at substantially the same etch rate.
  • the isotropic etching is a plasma etching process using SF6, CHF 3 , CF or other well known chemistries commonly used for etching dielectric materials.
  • the isotropic etching process is a wet etch process, such as a wet etch process using a buffered oxide etch (BOE).
  • Metal layer 108 is formed on the surface of substrate 102 and the surface of support regions 104A to 104C.
  • Metal layer 108 can be a copper layer or a copper-alloy (Cu-alloy) layer or a multilayer metal deposition such as Tungsten coated with Copper-Nickel-Gold (Cu/Ni/Au).
  • the contact elements are formed using a small-grained copper-beryllium (CuBe) alloy and then plated with electroless Nickel-Gold (Ni/Au) to provide a non-oxidizing surface.
  • Metal layer 108 can be deposited by a CVD process, by electro plating, by sputtering, by physical vapor deposition (PVD) or using other conventional metal film deposition techniques.
  • a mask layer is deposited and patterned into mask regions 110A to 110C using a conventional lithography process.
  • Mask regions 110A to 110C define areas of metal layer 108 to be protected from subsequent etching.
  • metal portions 108A to 108C are formed as shown in Figure 7G.
  • Each of metal portions 108A to 108C includes a base portion formed on substrate 102 and a curved spring portion fo ⁇ ned on a respective support region (104A to 104C). Accordingly, the curved spring portion of each metal portion assumes the shape of the underlying support region, projecting above the substrate surface and having a curvature that provides a wiping action when applied to contact a contact point.
  • Figure 7H such as by using a wet etch or an anisotropic plasma etch or other etch process. If the support layer is formed using an oxide layer, a buffered oxide etchant can be used to remove the support regions. As a result, free standing contact elements 112A to 112C are formed on substrate 102.
  • a connector can be fabrication with contact elements having a variety of properties. For example, a first group of contact elements can be formed with a first pitch while a second group of contact elements can be fo ⁇ ned with a second pitch greater or smaller than the first pitch. Other variations in the electrical and mechanical properties of the contact element are possible, as will be described in more detail below.
  • Figures 8 A to 8H illustrate the processing steps for forming connector 70 of
  • Figure 5 A according to one embodiment of the present invention.
  • the processing steps shown in Figures 8A to 8H are substantially the same as the processing steps shown in Figures 7A to 7H.
  • Figures 8A to 8H illustrate that different configuration of contact elements can be fabricated by using suitably designed mask patterns.
  • a support layer 124 is formed on a substrate 122.
  • a mask layer 126 is formed on the support layer for defining mask regions for forming the connector of Figure 5 A.
  • mask regions 126 A and 126B ( Figure 8B) are positioned closed together to allow a contact element including two curved spring portion to be formed.
  • support regions 124A and 124B are formed ( Figure 8C).
  • the mask regions are removed to expose the support regions ( Figure 8D).
  • support regions 124A and 124B are subjected to an isotropic etching process to shape the structures so that the top surface of the support regions includes rounded corners ( Figure 8E).
  • a metal layer 128 is deposited over the surface of substrate 122 and over the top surface of support regions 124A and 124B ( Figure 8F).
  • a mask pattern, including regions 130A and 130B, is defined on metal layer 128. After metal layer 128 is etched using mask regions 130A and 130B as mask, metal portions 128A and 128B are formed ( Figure 8G).
  • Each of metal portions 128A and 128B includes a base portion formed on substrate 122 and a curved spring portion formed on the respective support region (124A or 124B).
  • the curved spring portion of each metal portion assumes the shape of the underlying support region, projecting above the substrate surface and having a curvature that provides a wiping action when applied to contact a contact point.
  • the distal ends of metal portions 128A and 128B are fo ⁇ ned facing each other.
  • support regions 124 A to 124B are removed ( Figure 8H).
  • a free standing contact element 132 is fo ⁇ ned on substrate 102.
  • the two metal portions of contact element 132 appears to unconnected.
  • the base portions of the metal portions are connected such as by forming a ring around the contact element or the base portions can be connected through conductive layers formed in substrate 122.
  • Figures 9A to 9H illustrate the processing steps for forming connector 70 of
  • FIG. 5 A according to an alternate embodiment of the present invention.
  • a substrate 142 including predefined circuitry 145 is provided.
  • Predefined circuitry 145 can include interconnected metal layers or other electrical devices, such as capacitors or inductors, which are typically fo ⁇ ned in substrate 142.
  • a top metal portion 147 is formed on the top surface of substrate 142 to be connected to the contact element to be formed.
  • a support layer 144 and a mask layer 146 are fo ⁇ ned on the top surface of substrate 142.
  • the processing steps proceed in a similar manner as described above with reference to Figures 8 A to 8H.
  • Mask layer 146 is patterned ( Figure 9B) and support layer 144 is etched accordingly to formed support regions 144A and 144B ( Figure 9C). The mask regions are removed to expose the support regions ( Figure 9D). Then, an isotropic etching process is ca ⁇ ied out the round out the top corners of support regions 144A and 144B ( Figure 9E). A metal layer 148 is deposited on the surface of substrate 142 and over the support regions ( Figure 9F). Metal layer 148 is formed over top metal portion 147. As a result, metal layer 148 is eclectically connected to circuit 145.
  • Metal layer 148 is patterned by a mask layer 150 ( Figure 9F) and subjected to an etching process. Metal portions 148A and 148B are thus formed ( Figure 9G) having distal ends pointing towards each other. Support portions 144 A and 144B are removed to complete the fabrication of contact element 152 ( Figure 9H).
  • contact element 152 is electrically connected to circuit 145.
  • circuit 145 can be formed to electrically connect certain contact elements together.
  • Circuit 145 can also be used to connect certain contact elements to electrical devices such as a capacitor or an inductor formed in or on substrate 142.
  • Fabricating contact element 152 as part of an integrated circuit manufacturing process provides further advantage. Specifically, a continuous electrical path is fo ⁇ ned between contact element 152 and the underlying circuit 145. There is no metal discontinuity or impedance mismatch between the contact element and the associated circuit. In some prior art connectors, a gold bond wire is used to form the contact element.
  • the contact element of the present invention does not suffer from the limitations of the conventional connector systems and a connector built using the contact elements of the present invention can be used in demanding high frequency and high performance applications.
  • contact elements of the connector of the present invention are formed using semiconductor fabrication processes, contact elements having a variety of mechanical and electrical properties can be formed.
  • semiconductor fabrication processing steps allows a connector to be built to include contact elements having different mechanical and/or electrical properties.
  • a connector of the present invention is provided with contact elements having different operating properties. That is, the connector includes heterogeneous contact elements where the operating properties of the contact elements can be selected to meet requirements in the desired application.
  • the operating properties of a contact element refer to the electrical, mechanical and reliability properties of the contact element.
  • the connector of the present invention can be made to meet all of the stringent electrical, mechanical and reliability requirements for high-performance interconnect applications.
  • the following mechanical properties can be specifically engineered for a contact element or a set of contact elements to achieve certain desired operational characteristics.
  • the contact force for each contact element can be selected to ensure either a low resistance connection for some contact elements or a low overall contact force for the connector.
  • the elastic working range of each contact element over which the contact element operates as required electrically can be varied between contact elements.
  • the vertical height of each contact element can be varied.
  • the pitch or horizontal dimensions of the contact element can be varied.
  • the electrical properties can be specifically engineered for a contact element or a set of contact elements to achieve certain desired operational characteristics.
  • the DC resistance, the impedance, the inductance and the cunent canying capacity of each contact element can be varied between contact elements.
  • a group of contact elements can be engineered to have lower resistance or a group of contact elements can be engineered to have low inductance.
  • the contact elements can be engineered to obtain the desired reliability properties for a contact element or a set of contact elements to achieve certain desired operational characteristics.
  • the contact elements can be engineered to display no or minimal performance degradation after environmental stresses such as thermal cycling, thermal shock and vibration, conosion testing, and humidity testing.
  • the contact elements can also be engineering to meet other reliability requirements defined by industry standards, such as those defined by the Electronics Industry Alliance (EIA).
  • EIA Electronics Industry Alliance
  • the mechanical and electrical properties of the contact elements can be modified by changing the following design parameters. First, the thickness of the curved spring portion of the contact element can be selected to give a desired contact force.
  • a thickness of about 30 microns typically gives low contact force on the order of 10 grams or less while a flange thickness of 40 microns gives a higher contact force of 20 grams for the same displacement.
  • the width, length and shape of the curved sprint portion can also be selected to give the desired contact force.
  • the number of curved spring portions to include in a contact element can be selected to achieve the desired contact force, the desired cunent canying capacity and the desired contact resistance. For example, doubling the number of curved spring portions roughly doubles the contact force and cunent canying capacity while roughly decreasing the contact resistance by a factor of two.
  • specific metal composition and treatment can be selected to obtain the desired elastic and conductivity characteristics.
  • Cu-alloys such as copper-beryllium
  • metal multi-layers can be used to provide both excellent mechanical and electrical properties.
  • a contact element is formed using titanium (Ti) coated with copper (Cu) and then with nickel (Ni) and finally with gold (Au) to form a Ti/Cu/Ni/Au multilayer.
  • the Ti will provide excellent elasticity and high mechanical durability while the Cu provides excellent conductivity and the Ni and Au layers provide excellent conosion resistance.
  • different metal deposition techniques such as plating or sputtering
  • different metal treatment techniques such as alloying, annealing, and other metallurgical techniques can be used to engineer specific desired properties for the contact elements.
  • the curvature of the curved spring portion can be designed to give certain electrical and mechanical properties.
  • the height of the curved spring portion, or the amount of projection from the base portion, can also be varied to give the desired electrical and mechanical properties.
  • Figures 10A and 10B are cross-sectional views of a connector according to an alternate embodiment of the present invention.
  • a connector 220 includes a first set of contact elements 224, 226 and 228 and a second set of contact elements 225 and 227, all formed on a substrate 222.
  • the first set of contact elements 224, 226 and 228 has a curved spring portion longer than the curved spring portion of the second set of contact elements 225 and 227. In other words, the height of the curved spring portion of contact elements 224, 226 and 228 is greater than the height of the curved spring portion of contact elements 225 and 227.
  • connector 220 of the present invention can be advantageously applied in "hot-swapping" applications.
  • Hot- swapping refers to mounting or demounting a semiconductor device while the system to which the device is to be connected is electrically active without damaging to the semiconductor device or the system.
  • various power and ground pins and signal pins must be connected and disconnected in sequence and not at the same time in order to avoid damages to the device or the system.
  • taller contact elements can be use to make electrical connection before shorter contact elements. In this manner, a desired sequence of electrical connection can be made to enable hot-swapping operation.
  • connector 220 is to be connected to a semiconductor device 230 including metal pads 232 formed thereon.
  • an external biasing force F is applied to engage connector 220 with semiconductor device 230, the tall contact elements 224, 226 and 228 make contact with respective metal pads 232 first while shorter contact elements 225 and 227 remain unconnected.
  • Contact elements 224, 226 and 228 can be used to make electrical connection to power and ground pins of semiconductor device 230.
  • shorter contact elements 225 and 227, making connection to signal pins can then make connection with respective metal pads 232 on device 230.
  • the contact elements of the present invention have a large elastic working range, the first set of contact elements can be further compressed than the second set of contact elements without compromising the integrity of the contact elements. In this manner, connector 220 enables hot-swapping operation with semiconductor device 230.
  • a connector is provided with ground planes and the impedance of the contact elements can be controlled by varying the distance between the contact element for a signal pin and the ground plane or between the contact element for a signal pin and the contact element for a ground pin.
  • Figure 11 is a cross-sectional view of a connector including a ground plane for improving signal integrity and for controlling contact element impedance according to one embodiment of the present invention.
  • a connector 250 includes a contact element 254B which is to be connected to a signal pin on a semiconductor device.
  • Connector 250 further includes contact elements 254C which is to be connected to the ground potential of the semiconductor device.
  • Connector 250 includes a ground plane 255 which is formed in substrate 252.
  • Ground plane 255 can be formed on the top surface of substrate 252 or embedded in substrate 252. In Figure 11, the connection between contact elements 254A and 254C and ground plane 255 is shown. In actual implementation, contact elements 254A and 254C can be connected to ground plane 255 through metal connection on the surface of substrate 252 or through metal connection embedded in substrate 252.
  • ground plane 255 in connector 250 has the effect of improving the signal integrity of the AC electrical signals that are connected through connector 250. Specifically, as integrated circuits are being operated at higher and higher frequencies while the package lead count increases with decreasing lead pitches, the ability to improve signal integrity in a connector used to interconnect such integrated circuits becomes more important.
  • connector 250 includes ground plane 255 which functions to reduce noise and improve signal integrity of the connector.
  • the distance G between contact element 254B for a signal pin and contact elements 254A and 254C for the ground potential can be varied to obtain a desired impedance for contact element 254B.
  • Elements 257A, 257B and 257C can be included to further control the Electromagnetic emissions and rejection characteristic of the connector.
  • Figure 12 illustrates another embodiment of the connector of the present invention where a pair of contact elements 262 and 264 is used to couple to a pair of differential signals.
  • contact elements 262 and 264 are each fo ⁇ ned as including separate base portions 261 and 263. In this manner, a connector including contact elements 262 and 264 can be used to contact a semiconductor device including a pair of differential signals.
  • a connector incorporates embedded thermal dissipation structures to provide enhanced heat dissipation capability at specific contact elements. For instance, when a contact element engaging a lead of an electronic package ca ⁇ ies more than 1A of cunent, significant Joule heating can result creating a temperature rise of 20 degrees or more at the contact element.
  • a connector includes embedded thermal dissipation structures so as to effectively limit the temperature rise at specific contact elements. For example, the amount of temperature rise can be reduced to 10 degrees or less by the use of the embedded thermal dissipation structures in the connector of the present invention.
  • FIG. 13 illustrates a connector incorporating a thermally conductive plane according to one embodiment of the present invention.
  • connector 270 includes contact elements 274A to 274D fo ⁇ ned on the top surface of a substrate 272.
  • a thermally conductive plane 277 is formed in substrate 272 during the manufacturing process of substrate 272.
  • Thermally conductive plane 277 provides heat dissipation function for contact elements 274A to 274D.
  • the thermally conductive plane is formed using Cu.
  • the thermally conductive plane is formed using a filled epoxy which is not electrically conductive and thus can be in intimate contact with any circuitry that may be present in substrate 272 and connected to contact elements 274A to 274D.
  • thermally conductive plane 288 dissipates heat generated at the contact elements when the contact elements are coupled to a semiconductor device and are subjected to Joule heating.
  • a connector includes one or more coaxial contact elements.
  • Figure 14 illustrates a connector 300 including a coaxial contact element according to one embodiment of the present invention.
  • connector 300 includes a first contact element 320 and a second contact element 340 formed on the top surface of a substrate.
  • Contact elements 320 and 340 are formed in proximity to but electrical isolated from each other.
  • contact element 320 includes a base portion 322 formed as an outer ring including an aperture while contact element 340 includes a base portion 342 formed inside the aperture.
  • Each of contact elements 320 and 340 includes multiple curves spring portions.
  • contact element 320 includes eight curved spring portions 324 dispersed along the circular base portion 322.
  • Curved spring portions 324 are fo ⁇ ned linear projection from the base portion.
  • contact element 340 includes two curved spring portions 344A and 344B, each curved spring portion projecting in a spiral configuration from the base portion.
  • the curved spring portions of contact element 320 do not overlap with the curved spring portions of contact element 340.
  • contact element 320 is electrically isolated from contact element 340.
  • connector 300 can be used to interconnect a coaxial connection on a semiconductor device.
  • the outer contact element is coupled to a ground potential connection while the inner contact element is coupled to a signal connection, such as a high frequency signal.
  • each of the contact elements of the connector further includes a conductive adhesion layer in the base portion of the contact element for improving the adhesion of the contact element to the substrate.
  • Figures 15A to 15H illustrate the processing steps for forming an anay of connectors according to an alternate embodiment of the present invention. Like elements in Figures 7 A to 7H and 15A to 15H are given like reference numerals to simplify the discussion.
  • a substrate 102 on which the contact elements are to be formed is provided.
  • Substrate 102 can be a silicon wafer or ceramic wafer and may include a dielectric layer formed thereon (not shown in Figure 15 A).
  • a conductive adhesion layer 103 is deposited on substrate 102 or on top of the dielectric layer if present.
  • Conductive adhesion layer 103 can be a metal layer, such as copper-beryllium (CuBe) or titanium (Ti), or a conductive polymer-based adhesive, or other conductive adhesive.
  • a support layer 104 is formed on the adhesion layer 103.
  • Support layer 104 can be a deposited dielectric layer, such as an oxide or nitride layer, a spin-on dielectric, a polymer, or any other suitable etchable material.
  • a mask layer 106 is formed on the top surface of support layer 104.
  • Mask layer 106 is used in conjunction with a conventional lithography process to define a pattern on support layer 104 using mask layer 106.
  • a mask pattern including regions 106A to 106C, is formed on the surface of support layer 104 defining areas of support layer 104 to be protected from subsequent etching.
  • an anisotropic etching process is performed using regions 106A to 106C as a mask. As a result of the anisotropic etching process, support layer 104 not covered by a patterned mask layer is removed.
  • the anisotropic etching process stops on conductive adhesion layer 103 or partially in conductive adhesion layer 103.
  • conductive adhesion layer 103 remains after the anisotropic etch process.
  • support regions 104 A to 104C are formed on the conductive adhesion layer.
  • the mask pattern including regions 106A to 106C is subsequently removed to expose the support regions ( Figure 15D).
  • support regions 104A to 104C are then subjected to an isotropic etching process.
  • An isotropic etching process remove material under etch in the vertical and horizontal directions at substantially the same etch rate.
  • the top corners of support regions 104A to 104C are rounded off as shown in Figure 15E.
  • a metal layer 108 is formed on the surface of conductive adhesion layer 103 and the surface of support regions 104A to 104C.
  • Metal layer 108 can be a copper layer or a copper-alloy (Cu-alloy) layer or a multilayer metal deposition such as Tungsten coated with Copper-Nickel-Gold (Cu/Ni/Au).
  • the contact elements are formed using a small-grained copper-beryllium (CuBe) alloy and then plated with electroless Nickel-Gold (Ni/Au) to provide a non-oxidizing surface.
  • Metal layer 108 can be deposited by a CVD process, by electro plating, by sputtering, by physical vapor deposition (PVD) or using other conventional metal film deposition techniques.
  • a mask layer is deposited and patterned into mask regions 110A to 110C using a conventional lithography process. Mask regions 110A to 110C define areas of metal layer 108 to be protected from subsequent etching.
  • each of metal portions 108A to 108C includes a base portion formed on a respective conductive adhesion portion and a curved spring portion formed on a respective support region (104A to 104C). Accordingly, the curved spring portion of each metal portion assumes the shape of the underlying support region, projecting above the substrate surface and having a curvature that provides a wiping action when applied to contact a contact point.
  • the base portion of each metal portion is attached to a respective conductive adhesion portion which functions to enhance the adhesion of each base portion to substrate 102.
  • each of contact elements 112A to 112C effectively includes an extended base portion.
  • each conductive adhesion portion serves to extend the surface area of the base portion to provide more surface area for attaching the contact element to substrate 102. In this manner, the reliability of the contact elements can be improved.

Abstract

L'invention porte sur un connecteur, un procédé de formation associé, afin de se relier électriquement à des tampons formés sur un dispositif à semi-conducteurs comprenant un substrat et un réseau d'éléments de contact faits de matériau conducteur formé sur le substrat. Chaque élément de contact comprend une partie de base fixée à la surface supérieure du substrat et une partie de ressort courbée qui s'étend depuis la partie de base et présente une extrémité distale faisant saillie au-dessus du substrat. La partie de ressort courbée est formée pour se courber loin d'un plan de contact et présente une inclinaison conçue pour fournir une action de balayage contrôlée lors de son introduction dans un tampon respectif du dispositif à semi-conducteurs.
EP04813215A 2003-12-08 2004-12-07 Connecteur permettant d'etablir un contact electrique a des echelles de semi-conducteurs et procede de formation associe Withdrawn EP1697989A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US10/731,213 US20050120553A1 (en) 2003-12-08 2003-12-08 Method for forming MEMS grid array connector
US10/731,669 US7244125B2 (en) 2003-12-08 2003-12-08 Connector for making electrical contact at semiconductor scales
PCT/US2004/040868 WO2005057652A2 (fr) 2003-12-08 2004-12-07 Connecteur permettant d'etablir un contact electrique a des echelles de semi-conducteurs et procede de formation associe

Publications (1)

Publication Number Publication Date
EP1697989A2 true EP1697989A2 (fr) 2006-09-06

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EP04813215A Withdrawn EP1697989A2 (fr) 2003-12-08 2004-12-07 Connecteur permettant d'etablir un contact electrique a des echelles de semi-conducteurs et procede de formation associe

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Country Link
EP (1) EP1697989A2 (fr)
TW (1) TWI257695B (fr)
WO (1) WO2005057652A2 (fr)

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US7924035B2 (en) * 2008-07-15 2011-04-12 Formfactor, Inc. Probe card assembly for electronic device testing with DC test resource sharing
WO2011161855A1 (fr) * 2010-06-23 2011-12-29 山一電機株式会社 Tête de contact, embout de sonde avec la tête de contact et dispositif de connexion électrique utilisant l'embout de sonde
US8778738B1 (en) 2013-02-19 2014-07-15 Taiwan Semiconductor Manufacturing Company, Ltd. Packaged semiconductor devices and packaging devices and methods
US9953907B2 (en) 2013-01-29 2018-04-24 Taiwan Semiconductor Manufacturing Company, Ltd. PoP device
WO2021037827A1 (fr) * 2019-08-28 2021-03-04 Asml Netherlands B.V. Procédé, appareil et système de mise à la masse de tranche
CN113130432B (zh) * 2019-12-30 2022-12-27 华为机器有限公司 一种电子模块及电子设备

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US5152695A (en) * 1991-10-10 1992-10-06 Amp Incorporated Surface mount electrical connector
US5802699A (en) * 1994-06-07 1998-09-08 Tessera, Inc. Methods of assembling microelectronic assembly with socket for engaging bump leads
US6807734B2 (en) * 1998-02-13 2004-10-26 Formfactor, Inc. Microelectronic contact structures, and methods of making same
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US20030022532A1 (en) * 2001-07-27 2003-01-30 Clements Bradley E. Electrical contact
US6684499B2 (en) * 2002-01-07 2004-02-03 Xerox Corporation Method for fabricating a spring structure

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Also Published As

Publication number Publication date
TWI257695B (en) 2006-07-01
WO2005057652A3 (fr) 2006-01-05
WO2005057652A2 (fr) 2005-06-23
TW200532880A (en) 2005-10-01

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