Patent Publication Number: US-8118602-B2

Title: Method of connecting two area array devices using a printed circuit board with holes with conductors electrically connected to each other

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 12/642,066 U.S. entitled “A PRINTED CIRCUIT BOARD WITH HOLES WITH CONDUCTORS COMPRESSING A COMPLIANT PORTION OF CONTACT POSTS” and filed on Dec. 18, 2009 for Brian S. Beaman, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to electrical connections and more particularly relates to electrical connections for an area array device. 
     BACKGROUND 
     Description of the Related Art 
     An area array device has an array of electrical contact pads on a face of the device, instead of having pins or other contacts around a perimeter of the device. An array of contact pads provides far more connections than do contacts around a perimeter. Area array devices also have heat conduction and electrical performance advantages. Area array devices can be electrically connected by using a socket, or by directly soldering the contact pads to form connections. 
     Area array sockets, however, typically do not provide integral connections between contacts within the socket or to other auxiliary electrical devices. Instead, area array sockets usually connect the area array device contact pads directly, linearly, to a circuit board, another area array device, or the like. For example, one type of area array socket uses a molded plastic housing with electrically conductive contacts stitched or staked through the housing. This type of socket doesn&#39;t allow for internal connections within the socket, but simply makes a one-to-one connection straight through the socket using the contacts. Strict one-to-one connections limit the configurability and the functionality of an area array socket and hinder integration with other electronic components. 
     Because the connections in traditional sockets are direct, one-to-one connections, they also typically cause wiring congestion around the socket, especially with high contact count area array devices. Additionally, area array sockets are often difficult to repair or reconfigure. The socket&#39;s contacts are often permanently attached to the socket, making repair or reconfiguration of the socket difficult or impossible. In such a configuration, individual contacts usually cannot be repositioned or replaced without replacing the entire socket. 
     BRIEF SUMMARY 
     From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method that provide integral electrical connections within an area array socket. Beneficially, such an apparatus, system, and method would relieve wiring congestion around the socket, and would be repairable and reconfigurable. 
     The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available electrical connections for an area array device. Accordingly, the present invention has been developed to provide an apparatus, system, and method for providing electrical connections for an area array device that overcome many or all of the above-discussed shortcomings in the art. 
     The apparatus to provide electrical connections for an area array device is provided with a plurality of elements. These elements in the described embodiments include a plurality of holes, a plurality of electrically conductive contact posts, a compliant portion of each contact post, and a spring portion of each contact post. In a further embodiment, the elements include a second plurality of electrically conductive contact posts, one or more circuit traces, one or more electrical devices, an electrical connector, a seating portion of each contact post, a housing, and a press device. 
     In one embodiment, the plurality of holes is disposed within a circuit board. In a further embodiment, each hole comprises a conductor within the hole and an opening on a side of the circuit board. In one embodiment, the plurality of contact posts extends from the openings of at least a portion of the plurality of holes. The plurality of contact posts, in another embodiment, is disposed in a pattern corresponding to contact pads on an area array device. 
     In one embodiment, the compliant portion of each contact post is inserted within one of the plurality of holes. The conductor within the hole, in a further embodiment, compresses the compliant portion to removably secure the contact post within the hole and to provide an electrical connection between the contact post and the conductor within the hole. In one embodiment, the compliant portion comprises an eye of the needle compliant pin section. 
     The spring portion of each contact post, in one embodiment, extends away from the circuit board. In a further embodiment, the spring portion is compressible toward the circuit board in response to contact with a contact pad of the area array device. In another embodiment, the spring portion provides an electrical connection between the contact post and the contact pad in response to the contact with the contact pad. In one embodiment, the spring portion is selected from the group consisting of a cantilever beam, a radial spring, a fuzz button, and a C spring. 
     In one embodiment, the second plurality of electrically conductive contact posts extends from opposite openings of at least a portion of the plurality of holes. The opposite openings, in one embodiment, are disposed in an opposite side of the circuit board. The conductors within the holes, in a further embodiment, extend between the openings and the opposite openings. In one embodiment, the second plurality of contact posts is disposed in a pattern corresponding to contact pads on a second area array device and the circuit board comprises an interposer between the area array device and the second area array device. 
     In one embodiment, the one or more circuit traces are disposed on the circuit board. The one or more circuit traces, in a further embodiment, are in electrical communication with the conductors within one or more of the holes. In one embodiment, the one or more electrical devices are coupled to the one or more circuit traces. The one or more electrical devices, in another embodiment, are in electrical communication with the conductors within one or more of the holes through the one or more circuit traces. 
     In one embodiment, the electrical connector is disposed on a perpendicular side of the circuit board. The electrical connector, in another embodiment, is coupled to the one or more circuit traces. The electrical connector, in a further embodiment, is in electrical communication with the conductors within one or more of the holes through the one or more circuit traces. 
     In one embodiment, the seating portion of each contact post is disposed between the compliant portion and the spring portion. In a further embodiment, the seating portion has a width that is greater than a diameter of a hole. The seating portion, in another embodiment, is disposed against the side of the circuit board to prevent further insertion of the contact posts into the plurality of holes. 
     In one embodiment, the housing is disposed adjacent to the circuit board on the side of the circuit board. The housing, in a further embodiment, substantially circumscribes the plurality of contact posts. In another embodiment, at least a part of the spring portion of each contact post extends beyond a surface of the housing that faces away from the circuit board. The surface of the housing, in one embodiment, is formed to receive the area array device. In a further embodiment, the surface of the housing is positioned to prevent the contact posts from contacting each other in response to contact with the contact pads of the area array device. The housing, in another embodiment, comprises a plurality of slots that interface with the contact posts to removably secure the contact posts to the housing. 
     In one embodiment, the press device clamps the circuit board and the area array device together. In a further embodiment, the contact pads on the area array device contact the spring portions of the plurality of contact posts in response to the clamping of the press device, compressing the spring portions toward the circuit board. 
     A system of the present invention is also presented to provide electrical connections for an area array device. The system may be embodied by a circuit board, an area array device, a plurality of holes, a plurality of electrically conductive contact posts, a compliant portion of each contact post, and a spring portion of each contact post. In particular, the system, in one embodiment, includes a second plurality of electrically conductive contact posts, one or more circuit traces, one or more electrical devices, an electrical connector, a seating portion of each contact post, a housing, and a press device. 
     A method of the present invention is also presented for providing electrical connections for an area array device. The method in the disclosed embodiments substantially includes the steps necessary to carry out the functions presented above with respect to the operation of the described apparatus and system. In one embodiment, the method includes forming a plurality of holes within a circuit board. Each hole, in a further embodiment, comprises a conductor within the hole and an opening on a side of the circuit board. 
     The method, in a further embodiment, includes forming a plurality of electrically conductive contact posts. In another embodiment, the method includes forming a compliant portion on an end of each contact post. In a further embodiment, the compliant portion is sized for compressible insertion within one of the holes. In one embodiment, the method includes forming a spring portion on an opposite end of each contact post. In another embodiment, the spring portion is compressible toward the compliant portion. 
     In one embodiment, the method includes inserting the compliant portion of the plurality of contact posts into the openings of at least a portion of the plurality of holes. The compliant portions, in a further embodiment, are inserted in a pattern corresponding to contact pads disposed on an area array device. In another embodiment, the conductors within the holes compress the compliant portions to removably secure the contact posts within the holes and to provide electrical connections between the contact posts and the conductors. In one embodiment, the spring portions extend away from the circuit board. In a further embodiment, the spring portions are compressible toward the circuit board in response to contact with the contact pads of the area array device. The spring portions, in another embodiment, provide electrical connections between the contact posts and the contact pads in response to the contact with the contact pad. 
     An additional apparatus to provide electrical connections for an area array device is provided. In one embodiment, the additional apparatus includes a plurality of holes disposed within a circuit board of a land grid array socket. Each hole, in one embodiment, comprises a conductor within the hole and an opening on a side of the circuit board. 
     In a further embodiment, a plurality of electrically conductive contact posts extends from the openings of at least a portion of the plurality of holes. The plurality of contact posts, in one embodiment, is disposed in a pattern corresponding to contact pads disposed on an area array device. 
     In one embodiment, a compliant portion of each contact post comprises an eye of the needle compliant pin section. The compliant portion, in a further embodiment, is inserted within one of the plurality of holes. In another embodiment, the conductor within the hole compresses the eye of the needle to removably secure the contact post within the hole and to provide an electrical connection between the contact post and the conductor within the hole. 
     In another embodiment, a spring portion of each contact post extends away from the circuit board. The spring portion, in one embodiment, comprises a cantilever beam that is compressible toward the circuit board in response to contact with a contact pad of the area array device. In a further embodiment, the spring portion provides an electrical connection between the spring portion and the contact pad in response to the contact with the contact pad. 
     A third apparatus is provided to provide electrical connections for an area array device. The third apparatus, in one embodiment, includes a plurality of holes, a plurality of electrically conductive contact posts, a compliant portion of each contact post, a spring portion of each contact post, a seating portion of each contact post, a housing, a second plurality of electrically conductive contact posts, one or more circuit traces, one or more electrical devices, and an electrical conductor. 
     The plurality of holes, in one embodiment, is disposed within an interposing circuit board within a land grid array socket. In a further embodiment, each hole comprises a conductor within the hole and an opening on a side of the circuit board. The plurality of contact posts, in one embodiment, extends from the openings of at least a portion of the plurality of holes. The plurality of contact posts, in a further embodiment, is disposed in a pattern corresponding to contact pads on an area array device. 
     In one embodiment, the compliant portion of each contact post comprises an eye of the needle compliant pin section. The compliant portion, in a further embodiment, is inserted within one of the plurality of holes. In another embodiment, the conductor within the hole compresses the eye of the needle to removably secure the contact post within the hole and provides an electrical connection between the contact post and the conductor within the hole. 
     The spring portion of each contact post, in one embodiment, extends away from the circuit board. In a further embodiment, the spring portion comprises a cantilever beam that is compressible toward the circuit board in response to contact with a contact pad of the area array device. The spring portion, in another embodiment, provides an electrical connection between the spring portion and the contact pad in response to the contact with the contact pad. 
     The seating portion of each contact post, in one embodiment, is disposed between the compliant portion and the spring portion. The seating portion, in a further embodiment, has a width greater than a diameter of a hole. In another embodiment, the seating portion is disposed against the side of the circuit board to prevent further insertion of the contact posts into the plurality of holes. 
     In one embodiment, the housing is disposed adjacent to the circuit board on the side of the circuit board. The housing, in a further embodiment, substantially circumscribes the plurality of contact posts. In another embodiment, at least a part of the spring portion of each contact post extends beyond a surface of the housing that faces away from the circuit board. The surface of the housing, in one embodiment, is formed to receive the area array device. In another embodiment, the surface of the housing is positioned to prevent the contact posts from contacting each other in response to contact with the contact pads of the area array device. The housing, in a further embodiment, comprises a plurality of slots that interface with the contact posts to removably secure the contact posts to the housing. 
     The second plurality of electrically conductive contact posts, in one embodiment, extends from opposite openings of at least a portion of the plurality of holes. In another embodiment, the opposite openings are disposed in an opposite side of the circuit board and the conductors within the holes extend between the openings and the opposite openings. In another embodiment, the second plurality of contact posts is disposed in a pattern corresponding to contact pads on a second area array device. The circuit board, in a further embodiment, comprises an interposer between the area array device and the second area array device. 
     In one embodiment, the one or more circuit traces are disposed on the circuit board and are in electrical communication with the conductors within one or more of the holes. The one or more electrical devices, in a further embodiment, are coupled to the one or more circuit traces and are in electrical communication with the conductors within one or more of the holes through the one or more circuit traces. In another embodiment, the electrical connector is disposed on a perpendicular side of the circuit board and is coupled to the one or more circuit traces. The electrical connector, in a further embodiment, is in electrical communication with the conductors within one or more of the holes through the one or more circuit traces. 
     Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment. 
     Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention. 
     These features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which: 
         FIG. 1  is a schematic block diagram illustrating one embodiment of a system to provide electrical connections for an area array device in accordance with the present invention; 
         FIG. 2  is a schematic block diagram illustrating another embodiment of a system to provide electrical connections for an area array device in accordance with the present invention; 
         FIG. 3  is a schematic block diagram illustrating one embodiment of a circuit board in accordance with the present invention; 
         FIG. 4A  is a schematic block diagram illustrating one embodiment of a contact post in accordance with the present invention; 
         FIG. 4B  is a schematic block diagram illustrating another embodiment of a contact post in accordance with the present invention; 
         FIG. 5A  is a schematic block diagram illustrating embodiments of spring portions of a contact post in accordance with the present invention; 
         FIG. 5B  is a schematic block diagram illustrating embodiments of compliant portions of a contact post in accordance with the present invention; 
         FIG. 6A  is a schematic block diagram illustrating one embodiment of a contact post and a hole in accordance with the present invention; 
         FIG. 6B  is a schematic block diagram illustrating one embodiment of a contact post inserted in a hole in accordance with the present invention; 
         FIG. 7  is a schematic block diagram illustrating one embodiment of a circuit board and area array device in accordance with the present invention; 
         FIG. 8  is a schematic block diagram illustrating one embodiment of a housing in accordance with the present invention; 
         FIG. 9  is a schematic flow chart diagram illustrating one embodiment of a method for providing electrical connections for an area array device in accordance with the present invention; and 
         FIG. 10  is a schematic flow chart diagram illustrating another embodiment of a method for providing electrical connections for an area array device in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as an apparatus, system, or method. Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
     Furthermore, the described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention. 
     Aspects of the present invention are described below with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, and systems according to embodiments of the invention. In some alternative implementations, the functions noted in the blocks may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated figures. 
     Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. 
       FIG. 1  depicts one embodiment of a system  100  to provide electrical connections for an area array device  104 . In the depicted embodiment, the system  100  includes a circuit board  102 , an area array device  104 , a second area array device  106 , one or more housings  108 , a press device  110 , one or more circuit traces  112 , one or more electrical devices  114 , and an electrical connector  116 . The system  100  provides integral connections both between contact pads of the area array devices  104 ,  106  and from contact pads of the area array devices  104 ,  106  to external circuitry. 
     In the depicted embodiment, the circuit board  102  is an interposer in an area array device socket, providing electrical connections for the area array device  104  and the second area array device  106 . In a further embodiment, instead of being interposed between the area array device  104  and the second area array device  106 , the circuit board  102  may be a base circuit board to which the area array device  104  is connected, without a second area array device  104 . In the depicted embodiment, the circuit board  102  provides electrical connections for the area array device  104 ,  106  using removable, compressible contact posts or pins that are inserted into holes in the circuit board  102 . 
     The circuit board  102 , in one embodiment, is a planar element that provides structural support to the area array device  104  as well as electrical connections. The circuit board  102  may have multiple layers, such as electrically conductive layers, insulating layers, structural support layers, stiffening layers, heat dissipation layers, and the like. For example, in one embodiment, the circuit board  102  may be a printed circuit board, a laminate, a spacer, a substrate, or the like. In a further embodiment, the circuit board  102  includes one or more copper sheets laminated onto a non-conductive dielectric substrate using epoxy resin or the like. 
     The circuit board  102  has multiple holes (not shown) disposed within the circuit board  102 . Each hole has a conductor within it, and an opening on one or both sides of the circuit board  102 . The holes, in one embodiment, may be vias within the circuit board  102 , and the conductor may be plating, solder, wire, rivets, or the like within the holes. In one embodiment, the holes are through holes with openings on opposite sides of the circuit board  102 , and the conductors provide electrical connections through the holes from one side of the circuit board  102  to the other side. 
     The circuit board  102  also has contact posts (not shown) extending from at least some of the holes. The contact posts are electrically conductive, and provide the electrical connections for the area array device  104  and the second area array device  106 . In the depicted embodiment, a first group of contact posts extends from the openings in the holes toward the area array device  104  and a second group of contact posts extends from opposite openings in the holes toward the second area array device  106 . In a different embodiment, the circuit board  102  may only have contact posts on a single side of the circuit board  102 , providing electrical connections to a single area array device  104 . 
     The first group of contact posts is in a pattern that corresponds to contact pads on the area array device  104 , and the second group of contact posts is in a pattern that corresponds to contact pads on the second area array device  106 . The patterns of the first group of contact posts and the second group of contact posts may be the same, such that there is a one-to-one direct connection between the area array device  104  and the second area array device  106 , or the patterns may be different. 
     As will be described in greater detail with regard to  FIG. 4A  and  FIG. 4B , each contact post has a compliant portion and a spring portion. The compliant portion is inserted within a hole to removably secure the contact post within the hole and to electrically connect the contact post to the conductor within the hole. The spring portion extends away from the circuit board  102  and is compressible toward the circuit board  102 . The spring portion contacts the contact pads on one of the area array devices  104 ,  106 , providing an electrical connection between an area array device  104 ,  106  and the contact post. The contact posts may further have a seating portion that interfaces with the circuit board  102  to orient the compliant portion within a hole to prevent further insertion of a contact post within the hole. 
     In one embodiment, the area array device  104  is an integrated circuit device, circuit board, or the like with an array of electrical contact pads disposed on one side. For example, in one embodiment, the area array device  104  may be a land grid array (“LGA”) device such as a processor or the like. The area array device  104  may be an integrated circuit itself, an integrated circuit mounted on a substrate, a circuit board, a circuit board with one or more electrical components, or the like. The contact pads on the area array device  104  are electrically conductive, comprising one or more materials such as copper, gold, nickel, and the like. The contact pads may comprise an alloy, may be plated, or may be otherwise finished or treated to facilitate electrical connections, prevent corrosion, and the like. 
     In one embodiment, the second area array device  106  is an area array device that is configured for interfacing with the area array device  104 . The second area array device  106  may be substantially similar to the area array device  104  described above. In one embodiment, the area array device  104  is an integrated circuit device and the second area array device  106  is a circuit board upon which the area array device  104  is mounted, with the circuit board  102  as an interposer that provides electrical connections between the area array device  104  and the second area array device  106 . 
     In one embodiment, the one or more housings  108  provide structural support between the circuit board  102  and the area array device  104  and/or the second area array device  106 . The one or more housings  108 , in the depicted embodiment, are disposed adjacent to the circuit board  102 . The one or more housings  108  circumscribe the contact posts. 
     Each housing  108  has a surface that is formed to receive and interface with an area array device  104 ,  106 . At least part of the spring portions of the contact posts extend beyond the surface of a housing  108 , to contact the contact pads on an area array device  104 ,  106 . The surface of a housing  108 , in one embodiment, is positioned to prevent contact posts from contacting each other as the spring portion compresses toward the circuit board  102 . The housings  108  may further include slots that interface with the contact posts to removably secure the contact posts to the housings  108 . The one or more housings  108  are discussed in greater detail with regard to  FIG. 8 . 
     In one embodiment, the press device  110  clamps the circuit board  102  and the area array devices  104 ,  106  together. The press device  110  forces the contact pads on the area array devices  104 ,  106  into contact with the spring portions of the contact posts, compressing the spring portions toward the circuit board  102  to form electrical connections with the contact pads. The press device  110  may include one or more clamping plates, clamping levers, fasteners, hinges, connectors, and the like to provide the clamping force. 
     In one embodiment, the one or more circuit traces  112  are disposed on the circuit board  102 . The circuit traces  112  provide electrical connections to and from the conductors in the holes in the circuit board  102 , which are electrically connected to the contact pads of the area array devices  104 ,  106 . 
     The circuit traces  112  are described in greater detail with regard to  FIG. 3 . In general, the circuit traces  112  may connect the conductors to other conductors in other holes, to the one or more electrical devices  114  mounted on the circuit board  102 , to the electrical connector  116 , and the like. The circuit traces  112  provide integral connections to the contact pads on the area array devices  104 ,  106 , increasing the utility and the configurability of the system  100 . 
     In one embodiment, the one or more electrical devices  114  are mounted on the circuit board  102  and are electrically connected to the circuit traces  112 . The electrical devices  114  may include active or passive electrical components, such as communications devices, voltage regulators, resistors, capacitors, and the like. The electrical devices  114  may include discrete or integrated electrical devices. 
     In one embodiment, the electrical connector  116  connects a circuit trace  112  to an external component or device. The electrical connector  116  may be a port, socket, or other connector that provides an electrical or optical connection to an external component, allowing electrical or fiber optic communications between the external component and the one or more area array devices  104 ,  106 . 
     Because the circuit traces  112 , the electrical devices  114 , and the electrical connector  116  are located on the circuit board  102  as part of an intermediate layer or interposer in the system  100 , they relieve some of the wiring congestion on the second area array device  106 . The second area array device  106 , in one embodiment, includes one or more additional circuit traces, electrical devices, electrical connectors, and the like. 
     For example, in one embodiment, connections to some contact pads on the area array device  104  may be connected directly through to contact pads on the second area array device  106 , some may be connected to the electrical devices  114  or the electrical connector  116 , and others may be connected to both. In a further embodiment, contact pads from the area array device  104  may be connected to other contact pads on the area array device  104 . Connections from contact pads on the area array device  104 , in another embodiment, may be rerouted to contact pads on the second area array device  106  that do not correspond to the same holes in the circuit board  102 . The system  100  provides a high level of configurability and flexibility in making connections with the area array device  104 . 
       FIG. 2  depicts an exploded cross sectional view of one embodiment of a system  200  to provide electrical connections for the area array device  104 . In the depicted embodiment, the system  200  includes the circuit board  102 , the area array device  104 , the second area array device  106 , the one or more housings  108 , and the press device  110 . In one embodiment, the system  200  may be substantially similar to the system  100  described with regard to  FIG. 1 . 
     In one embodiment, the circuit board  102  includes a group of holes  212 , a group of contact posts  210 , and a second group of contact posts  214 . Examples of the holes  212 , the contact posts  210 , and the second group of contact posts  214  are described above with regard to the circuit board  102  of  FIG. 1 . 
     In the depicted embodiment, each hole  212  in the group of holes  212  in the circuit board  102  is a through hole, with openings on two opposite sides of the circuit board  102 . Each of the holes  212  has a conductor within it, providing electrical connections between the openings of the holes  212 . 
     In the depicted embodiment, each of the contact posts  210  is removably inserted within an opening of the holes  212 . The conductors in the holes  212  compress compliant portions of the contact posts  210  to create an electrical connection between the contact posts  210  and the conductors, and to secure the contact posts  210  within the holes  212 . Spring portions of the contact posts  210  extend beyond the housing  108  toward contact pads  208  on the area array device  104 . 
     In the depicted embodiment, the spring portions of the contact posts  210  are cantilever beams, and the group of contact posts  210  is divided into two groups of oppositely facing contact posts  210 . The oppositely facing contact posts  210  balance a force from the wiping action of the cantilever beams on the contact posts  210  in response to the cantilever beams being pressed toward the circuit board  102  by the contact pads  208  of the area array device  104 . In another embodiment, the contact posts  210  may be arranged in a different balancing configuration, such as multiple groups each facing diagonally toward a center of the circuit board  102 , or the like. The contact posts  210  are arranged in a pattern corresponding to the contact pads  208  on the area array device  104 , so that the spring portions of the contact posts  210  are in contact with the contact pads  208  when compressed toward the circuit board  102 . 
     In the depicted embodiment, each of the second group of contact posts  214  are removably inserted within opposite openings of the holes  212 , such that the conductors within the holes  212  connect the first group of contact posts  210  and the second group of contact posts  214 . Each contact post  214  in the second group of contact posts  214  extend from the circuit board  102  toward contact pads  216  on the second area array device  106 . 
     The system  200  may have various scales, depending on the size and density of the contact pads  208 ,  216  on the area array devices  104 ,  106 . For example, in one embodiment, the holes  212  may have a diameter between about 10-25 mils. The compliant portion of the contact posts  210 ,  214 , in one embodiment, is slightly larger than the diameter of the holes  212 . In a further embodiment, the compliant portion of the contact posts  210 ,  214  is about twice as tall as it is wide, for example about 20-50 mils tall and about 10-25 mils wide. In an embodiment where the contact posts  210  are made from metallic sheets, such as copper, the contact posts  210  may be between about 2-6 mils thick. 
     In the depicted embodiment, the circuit board  102  is at least twice as thick as the height of compliant portions of the first group of contact posts  210  and the second group of contact posts  214 , such that the first group of contact posts  210  and the second group of contact posts  214  do not contact each other within the holes  212 . For example, in an embodiment where the compliant portion of the contact posts  210  is between about 20-25 mils in height, the circuit board  102  may be at least 40-50 mils thick to accommodate two compliant portions. 
     In the depicted embodiment, the conductors within the holes  212  provide an electrical connection between the contact posts  210  and the contact posts  214 . In a further embodiment, the first group of contact posts  210  and the second group of contact posts  214  may contact, overlap, intertwine, interlock, or the like with each other within the holes  212 . In an embodiment where the first group of contact posts  210  and the second group of contact posts  214  contact within the holes  212 , the compliant portion of an opposite contact post  210 ,  214  may be the conductor within the hole  212 , forming an electrical connection between the contact posts  210 ,  214  and/or removably securing the contact posts  210 ,  214  within the holes  212 . In another embodiment, the first group of contact posts  210  and the second group of contact posts  214  may contact, overlap, intertwine, interlock, or the like such that a width of the circuit board  102  may be reduced to less than double the height of the compliant portions. 
     The contact pads  208 ,  216 , in one embodiment, are made of an electrically conductive material, and may be metalized, plated, or the like to facilitate electrical connections between the contact pads  208 ,  216  and the contact posts  210 ,  214 . The contact posts  210 ,  214  are disposed in patterns on the area array devices  104 ,  106  to correspond with the contact pads  208 ,  216 . 
     In the depicted embodiment, the press device  110  includes one or more fasteners  202 , one or more clamping members  204 , and one or more corresponding fasteners  206 . The press device  110  clamps the circuit board  102  and the area array devices  104 ,  106  together, forcing the contact pads  208 ,  216  into contact with the spring portions of the contact posts  210 ,  214 . 
     In the depicted embodiment, a clamping member  204  is disposed on each side of the system  200  and the fasteners  202  engage with the corresponding fasteners  206  to compress the area array devices  104 ,  106  toward the circuit board  102 . In the depicted embodiment, the fasteners  202  include screws, bolts, or the like that extend through openings in the clamping members  204 , the circuit board  102 , and the second area array device  106  to engage the corresponding fasteners  206 , which are bolts. In a further embodiment, the press device  110  may include a hinge with clamping plates and a clamping lever, or may include a different press device. 
       FIG. 3  depicts one embodiment  300  of the circuit board  102 . In the depicted embodiment  300 , the circuit board  102  includes the group of holes  212 , one or more circuit traces  304 ,  306 ,  308 ,  310 ,  312 , the one or more electrical devices  114 , and the electrical connector  116 . 
     In one embodiment, the group of holes  212  each include a conductor  302  within the hole  212 . The conductors  302  are electrically conductive, and may circumscribe each hole  212 , may line a portion of each hole  212 , or the like such that the conductors  302  compress compliant portions of the contact posts  210 ,  214 . For example, in one embodiment, an interior wall of a hole  212  may be plated, metalized, lined, or the like with a conductive material such as copper, gold, nickel, an alloy, or the like that circumscribes the hole  212 , or a conductor  302  may be placed along one or more strips within the hole  212 . The design of the compliant portion of the contact posts  210 ,  214  may determine the type of conductor  302  used in the holes  212 . 
     Each of the holes  212 , in one embodiment, may extend through the circuit board  102  such that the first group of contact posts  210  may be inserted into a first opening of the holes  212  and the second group of contact posts  214  may be inserted into a second opening of the holes  212  to allow the circuit board  102  to be used as an interposer between the area array device  104  and the second area array device  106 . In a further embodiment, the circuit board  102  is not an interposer, but is a base circuit board with the contact posts  210  on a single side of the circuit board  102 , and the holes  212  may not be through holes, but may pass partially through the circuit board  102  and may have a single opening. 
     In one embodiment, the one or more circuit traces  304 ,  306 ,  308 ,  310 ,  312  are disposed on the circuit board  102  to provide integral electrical connections to and from the conductors  302  within the holes  212 . In the depicted embodiment  300 , the circuit trace  304  electrically connects a conductor  302  with the electrical connector  116 . In a further embodiment, multiple circuit traces may connect additional conductors  302  with the electrical connector  116 . The electrical connector  116 , in the depicted embodiment  300 , is disposed on a perpendicular side of the circuit board  102 . 
     In one embodiment, the electrical connector  116  may include additional components to manipulate, translate, and/or transform signals to and from the conductor  302 . For example, in one embodiment, the electrical connector  116  may include an optical transmitter and/or receiver to convert between electrical and optical signals for fiber optic communications. In a further embodiment, the electrical connector  116  may connect multiple circuit boards  102 , for integral connections between multiple area array devices  104 . 
     In the depicted embodiment  300 , the circuit trace  306  connects one conductor  302  to an electrical device  114 , and the circuit trace  308  connects another conductor  302  to the same electrical device  114 . Additional circuit traces may connect more conductors  302  to the same electrical device  114  or to other electrical devices  114 . As depicted, the circuit trace  310  connects a conductor  302  to an electrical device  114 . The circuit trace  312 , as depicted, connects a conductor  302  in a first hole  212  with a conductor  302  in a second hole  212 . The circuit trace  312 , in a further embodiment, may connect more than two conductors  302  from more than two holes  212 . 
       FIG. 4A  depicts one embodiment of the contact post  210 . In the depicted embodiment, the contact post  210  has a spring portion  402 , a seating portion  404 , and a compliant portion  406 . As depicted, the spring portion  402  is on a first end of the contact post  210  and the compliant portion  406  is on an opposite end of the contact post  210 , with the seating portion  404  between the spring portion  402  and the compliant portion  406 . 
     The contact post  210  is electrically conductive, and may be constructed of a single, continuous material, or may be constructed of separate materials that are connected to form a structural and electrical connection. For example, in one embodiment, the contact post  210  may be stamped from a single sheet of copper, or the like. In another embodiment, a spring portion  402 , such as a radial spring or fuzz button, may be welded, soldered, or otherwise structurally and electrically connected to a compliant portion  406 . 
     The spring portion  402  provides an electrical connection between a contact pad  208 ,  216  and the contact post  210  at a contact tip  408  of the contact post  210 . The spring portion  402  is compressible, such that the contact tip  408  is pressed against a contact pad  208 ,  216 . In the depicted embodiment, the spring portion  402  is a cantilever beam that compresses by bending at a joint. Other embodiments of the spring portion  402 , such as a C spring, a radial spring, and a fuzz button are depicted in  FIG. 5A . 
     The seating portion  404 , in one embodiment, has a width that is greater than a diameter of a hole  212 . As the compliant portion  406  is inserted into a hole  212 , the seating portion  404  contacts the side of the circuit board  102  around the hole  212 , preventing further insertion of the contact post  210  into the hole  212 . In another embodiment, the seating portion  404  may be positioned and shaped to orient the compliant portion  406  within a hole  212 . In a further embodiment, the seating portion  404  may interface with the housing  108  to secure the contact post  210  to the housing  108 . 
     In one embodiment, the compliant portion  406  is inwardly compressible, and has a width that is slightly greater than a diameter of a hole  212 . As the compliant portion  406  is inserted into a hole  212 , the wall of the hole  212  and/or the conductor  302  within the hole  212  compresses the compliant portion  406 . Once compressed, the compliant portion  406  presses outward, removably securing the contact post  210  within the hole  212  and making an electrical connection with the conductor  302 . 
     In the depicted embodiment, the compliant portion  406  is an eye of the needle compliant pin section  410 . The arms of the eye of the needle compliant pin section  410  bend inward in response to pressure from a wall of the hole  212  and/or the conductor  302  within the hole  212 . Other embodiments of the compliant portion  406 , such as a C shaped compliant structure and a split pin, are depicted in  FIG. 5B . 
       FIG. 4B  depicts another embodiment of the contact post  210 . In the depicted embodiment, the spring portion  402  includes a split contact tip  412 . A split contact tip  412 , due to its multiple contacts, may provide a more consistent connection with a contact pad  208 ,  216 . The seating portion  404 , as depicted, includes one or more carrier strips  414 . The carrier strips  414 , in one embodiment, facilitate insertion of the contact post  210  within a hole  212 . The carrier strips  414  may be manufacturing remnants from a reel of contact posts  210 , or may be designed expressly to facilitate insertion of the contact posts  210  into the holes  212 . In a further embodiment, the seating portion  404  may not include the carrier strips  414 , but may still be wider than the spring portion  402  to provide a surface for pressing the contact post  210  into a hole  212 . 
       FIG. 5A  depicts four embodiments of the spring portions  402  of the contact posts  210 . In the depicted embodiments, the contact post  210   a  has a C spring  502 , the contact post  210   b  has a radial spring  504 , contact post  210   c  has a fuzz button  506 , and contact post  210 d has a cantilever beam  508 . Many other designs for the spring portion  402  are possible, and the contact posts  210  may include another type of spring portion  402  that is electrically conductive and compressible toward the compliant portion  406 . 
     Each spring portion  402 , in the depicted embodiments, is compressible and electrically conductive. The contact post  210   a  is made from a single piece of material, with the C spring  502  bent to form the spring portion  402 . As depicted, the radial spring  504  is attached to the contact post  210   b  by welding, soldering, or the like to form a continuous structural and electrical connection. Similarly, in the depicted embodiment, the fuzz button  506 , a compacted mass of small wires, is attached to the contact post  210   c  to form a structural and electrical connection. The C spring  502 , the radial spring  504 , and the fuzz button  506  are each shaped to compress along a vertical axis in response to a compression force. 
     The cantilever beam  508  of the contact post  210   d  is substantially similar to the spring portion  402  depicted in  FIG. 4A  and  FIG. 4B . The cantilever beam  508  is formed in the contact post  210   d  by bending a single piece of material to form the spring portion  402  of the contact post  210   d . The cantilever beam  508 , in one embodiment, may move in an arc along both a vertical axis and a horizontal axis in response to a compression force, creating the wiping action described with regard to the contact posts  210  of  FIG. 2 . 
       FIG. 5B  depicts three embodiments of the compliant portions  406  of the contact posts  210 . In the depicted embodiments, the contact post  210   e  has a C shaped compliant structure  512 , the contact post  210   f  has a split pin  514 , and the contact post  210   g  has the eye of the needle compliant pin section  410  Like the spring portion  402 , many other designs for the compliant portion  406  are possible, and the contact posts  210  may include another type of compliant portion  406  that is compressibly insertable within a hole  212  to form an electrical connection with the conductor  302  within the hole  212 . 
     The C shaped compliant structure  512  of the contact post  210   e  is a C shaped bend at an end of the contact post  210   e  to form the compliant portion  406 . The C shaped compliant structure  512  is formed with a gap between ends, such that the C shaped compliant structure  512  bends inwardly upon itself in response to a compression force from a wall of a hole  212  and/or a conductor  302  within a hole  212 . Bending inwardly reduces the diameter of the C shaped compliant structure  512  allowing insertion of the C shaped compliant structure  512  in a hole  212 . In another embodiment, the C shaped compliant structure  512  may face downward, and may be bent, stamped, or otherwise formed in a downward facing C shape. 
     The split pin  514  of the contact post  210   f  has an elongated pin structure with two or more arms that are displaced outwardly from the pin structure. The arms of the split pin  514  are displaced along an axis of the elongated pin structure, for example side to side, front to back, diagonally, or the like. In the depicted embodiment, the arms of the split pin  514  are joined at the top and bottom, with a split in the middle. In another embodiment, the arms of the split pin  514  may be joined at a single end and open at another end. 
     The eye of the needle compliant pin section  410  of the contact post  210   g  has an eye, or hole in an elongated pin structure with walls of the eye bent or deformed outwardly around the eye. The walls or arms of the eye in the eye of the needle compliant pin section  410  are compressible inward toward the eye. The eye of the needle compliant pin section  410 , in one embodiment, is formed by piercing an elongated pin structure, forming the eye and forcing the walls of the eye outward. In a further embodiment, an outward facing surface of the eye of the needle compliant pin section  410  may be coined or the like after formation to prevent damage to the conductors  302  and/or the holes  212 . 
       FIG. 6A  depicts one embodiment of the contact post  210  and the hole  212 . In the depicted embodiment, the compliant portion  406  has an eye of the needle compliant pin section  410  that has a width that is slightly greater than a diameter of the hole  212  prior to insertion within the hole  212 . The hole  212 , as depicted, is plated or otherwise lined with the conductor  302 . 
       FIG. 6B  depicts one embodiment of the contact post  210  inserted into the hole  212 . As depicted, the compliant portion  406  is compressed by the conductor  302 , to removably secure the compliant portion  406  within the hole  212  and to form an electrical connection between the conductor  302  and the contact post  210 . In the depicted embodiment, the arms of the eye of the needle compliant pin section  410  are compressed inward by the conductor  302 . 
     The seating portion  404 , in the depicted embodiment, is seated against the upper surface of the hole  212  in the circuit board  102  (not shown). The seating portion  404  prevents further insertion of the compliant portion  406  into the hole  212 . As depicted, the hole  212  is at least twice as long as the compliant portion  406 , allowing for a second contact post  214  to be inserted in an opposite opening of the hole  212 . 
     The seating portion  404  also ensures that each contact post  210  is inserted into a hole  212  at a consistent depth, so that the spring portions  402  each contact a contact pad  208 ,  216 . The contact post  210 , in the depicted embodiment, also includes a carrier strip  414 , which may facilitate insertion of the contact post  210  into the hole  212  by providing a surface upon which an installing person or device may exert pressure. 
     As depicted, the contact post  210  is removable from the hole  212 . This provides flexibility in repairing and configuring the circuit board  102 . In one embodiment, the compliant portion  406  deforms the hole  212  and/or the conductor  302  to a certain degree upon insertion. In certain embodiments, this may cause the hole  212  to no longer secure a contact post  210  or the conductor  302  to no longer provide an electrical connection after too many repeated insertions and removals. 
       FIG. 7  depicts one embodiment  700  of the circuit board  102  and the area array device  104 . In the depicted embodiment  700 , the group of contact posts  210  is inserted into the group of holes  212  in the circuit board  102 . The group of contact posts  210  forms a rectangular pattern on the circuit board  102 , in six by six rows and columns. 
     As depicted, the contact pads  208  on the area array device  104  form a similar rectangular pattern in six by six rows and columns, corresponding to the pattern of the contact posts  210 . The area array device  104  is illustrated as flipped, to show the pattern of contact pads  208 . During installation of the area array device  104 , the contact pads  208  are oriented facing the contact posts  210  and clamped toward the contact posts  210  such that each contact post  210  forms an electrical connection with a contact pad  208 . Although the contact posts  210  and contact pads  208  are depicted in a six by six array in a rectangular pattern for illustration purposes, other embodiments may include hundreds or thousands of contact posts  210  and contact pads  208  in more complex patterns. 
       FIG. 8  depicts one embodiment of the housing  108 . In the depicted embodiment, the housing  108  includes one or more securing members  802 , one or more alignment members  804 , a surface  806 , one or more openings  808 , and one or more slots  810 . The housing  108 , in one embodiment, is formed of a durable, insulating material, such as a plastic, ceramic, or the like. 
     In one embodiment, the one or more securing members  802  apply pressure to the area array device  104 . The securing members  802  may help align the area array device  104  within the housing  108 , and may help the press device  110  clamp the area array device  104 . In the depicted embodiment, the securing members  802  are compressible, allowing the area array device  104  to be installed in the housing  108 . In one embodiment, the one or more alignment members  804  align the area array device  104  within the housing  108 . The securing members  802 , in one embodiment, press the area array device  104  against the alignment members  804  to align the contact posts  210  with the contact pads  208 . 
     In one embodiment, the surface  806  is formed to receive the area array device  104 . The securing members  802  and/or the alignment members  804  may position the area array device  104  to align the area array device  104  relative to the surface  806 . In the depicted embodiment, the one or more openings  808  are in the surface  806 . At least a part of the spring portions  402  of the group of contact posts  210  extend through the openings  808  beyond the surface  806  to contact the contact pads  208 . 
     The surface  806 , in one embodiment, is positioned to prevent the contact posts  210  from contacting each other as they are compressed by the contact pads  208 . Some types of spring portions  402 , such as the cantilever beam  508 , move along both a vertical axis and a horizontal axis in response to a compression force, and may contact other contact posts  210  if compressed too far. The surface  806 , in one embodiment, may prevent the contact posts  210  from compressing beyond a predefined point based on how far the contact posts  210  extend beyond the surface  806  of the housing  108 , preventing contact between the contact posts  210 . 
     In one embodiment, the one or more slots  810  are in the openings  808  to interface with the contact posts  210 . The slots  810  may removably secure the contact posts  210  to the housing  108 , and align the contact posts  210  relative to the housing  108 . For example, in one embodiment, a portion of the contact posts  210 , such as the seating portion  404 , may be wider than the spring portion  402 , and may have an interference fit with the slots  810 . Each slot  810  may pass through the entire housing  108 , or may pass partially through the housing  108  to align the contact posts  210  vertically within the openings  808 . 
     In one embodiment, the housing  108  may be joined to, formed with, or otherwise integrated with the circuit board  102 . For example, in one embodiment, the circuit board  102  may be a base portion of the housing  108 , with the holes  212  forming a base of the slots  810 , and the conductors  302  may be within the holes  212  at the base of the slots  810 . In another embodiment, one or more connectors or fasteners, the contact posts  210 , the press device  110 , or the like connect the housing  108  to the circuit board  102 . The housing  108  may include one or more additional openings, connectors, fasteners, alignment features, or the like (not shown) to facilitate connection, alignment, or integration with the circuit board  102 . 
       FIG. 9  depicts one embodiment of a method  900  for providing electrical connections for the area array device  104 . In one embodiment, the method  900  is an automated or manual process performed by a device assembler. The device assembler may be one or more automated assembly devices, assembly workers, assembly tools, and the like. The method  900  begins, and the device assembler forms  902  the holes  212  with the conductors  302  in the circuit board  102 . In one embodiment, the device assembler may form  902  the holes  212  using a mechanical drill bit, a laser drill, or the like. The device assembler may plate, solder, weld, insert, or otherwise place the conductors  302  within the holes  212 . 
     The device assembler forms  904  the contact posts  210 . In one embodiment, the contact posts  210  are formed  904  by stamping the contact posts  210  from a metal sheet, such as a copper sheet or the like. The contact posts  210 , in a further embodiment, may be formed as a reel or string of multiple contact posts  210  that may be separated at various points during the method  900 . In another embodiment, forming  904  the contact posts  210  may include attaching a compliant portion  406  to a spring portion  402  by welding, soldering, or the like. 
     The device assembler forms  906  the compliant portion  406  of each contact post  210 . The device assembler, in one embodiment, forms  906  the compliant portions  406  by piercing an end of the contact posts  210  to form the eye of the needle compliant pin section  410 . The forming  906  of the compliant portions  406 , in a further embodiment, may include coining edges of the compliant portions  406 . Coining dulls the edges and can prevent or minimize damage to the holes  212  and/or the conductors  302 . 
     The device assembler forms  908  the spring portion  402  of each contact post  210 . In one embodiment, forming  908  the spring portion  402  includes bending a cantilever beam  508 , a C spring  502 , or the like into each contact post  210 . In a further embodiment, forming  908  the spring portion  402  includes manufacturing the radial spring  504 , the fuzz button  506 , or another separate compliant portion  406  for attachment to the compliant portion  406  during the step of forming  904  the contact posts  210 . 
     The device assembler inserts  910  the compliant portion  406  of each contact post  210  into an opening of the holes  212  and the method  900  ends. In one embodiment, where the contact posts  210  are part of a reel or string of contact posts  210 , the device assembler may separate the contact posts  210  from the reel or string during or prior to insertion  910  of the contact posts  210  into the holes  212 . 
       FIG. 10  depicts one embodiment of a method  1000  for providing electrical connections for the area array device  104 . Like the method  900 , in one embodiment, the method  1000  is an automated or manual process performed by a device assembler. The method  1000  begins, and the device assembler forms  1002  the holes  212  with the conductors  302  in the circuit board  102 . The device assembler forms  1004  the contact posts  210 , forms  1006  the compliant portion  406  of each contact post  210 , and forms  1008  the spring portion  402  of each contact post  210 . 
     The device assembler inserts  1010  the compliant portion  406  of each contact post  210  into an opening of the holes  212 , and inserts  1012  the compliant portion  406  of each of the second group of contact posts  214  into opposite openings of the holes  212 . The device assembler clamps  1014  the circuit board  102 , the area array device  104 , and/or the second area array device  106  together to create electrical contacts between the contact posts  210 ,  214  and the contact pads  208 ,  216  using the press device  110 , and the method  1000  ends. 
     The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes,” “has,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.