Connector and interposer using connector

A connector conducting electricity between external electrodes while the connector is being compressed, the connector including: a columnar main body made of an elastic dielectric; a first contact terminal made of an inelastic conductor including first and second electrode sections provided on a top surface and a side surface of the columnar main body and a coupling section interconnecting the first and second electrode sections; a second contact terminal made of an inelastic conductor including third and fourth electrode sections provided on a bottom surface and a side surface of the columnar main body and a coupling section interconnecting the third and fourth electrode sections, the fourth electrode section being disposed in a position in which the fourth electrode section does not contact the second electrode section; and a conductor provided outside the main body and conducting electricity between the second and fourth electrode sections.

CROSS REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from the prior Japanese Patent Application NO. 2009-158159 filed on Jul. 2, 2009, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein are related to a connector electrically interconnects two opposed electrodes and an interposer using the connector.

BACKGROUND

When a semiconductor integrated circuit (IC) is mounted onto a circuit board, conventionally leads provided on the sides of the IC package are inserted into through-holes provided in lands of a circuit pattern on the circuit board and soldered to electrically connect to the lands. The numbers of input and output terminals of ICs have increased with the increase of the integration densities of ICs in these years. In addition, the operating frequencies of ICs have also increased. Along with the demand for high frequency characteristics has come growing demand for high-density mounting on circuit boards, short-distance interconnections, and finer pitches.

In these circumstances, a technique has been proposed in which input and output terminals are arranged in a grid array on the bottom surface of an IC package and an interposer is used to mount the IC package onto a circuit board in order to efficiently arrange the input and output terminals. An interposer is a thin high-terminal-density connector in which holes corresponding to input and output terminals arranged in a grid array of an IC package are provided in a sheet of insulating material and conductors (connectors) that conduct electricity between both surfaces of the sheet of insulating material are inserted in the holes.

Terminals are also provided on the circuit board in the similar grid array pattern.

Japanese Laid-open Patent Publication No. 2006-66407 discloses elastic connectors employing silicon spring electrodes. Japanese Laid-open Patent Publication No. 2001-176580 discloses an elastic connector in which wires formed in zig-zags, pleats or coils are incorporated in buttons made of an elastic material. JP-A-2001-176580 also discloses metal springs may be used instead of the wires.

However, the structure that uses silicon spring electrodes to make connecters elastic has a problem that the silicon spring electrodes have high electrical resistance. The configurations in which zig-zag, pleat or coiled wires or metal springs are incorporated in elastic main bodies have a problem that they are physically difficult to miniaturize.

SUMMARY

According to one aspect of the embodiments, there is provided a connector conducts electricity between electrode terminals located above and below the connector while the connector is being compressed. The connector includes a main body, a first contact terminal, a second contact terminal and a conductor. The main body is made of an elastic dielectric and is cylindrical in shape. The first contact terminal is an inelastic conductor including first and second electrode sections provided on the top and side surfaces, respectively, of the cylindrical main body and a coupling section interconnecting the first and second electrode sections. The second contact terminal includes third and fourth electrode sections provided on the bottom and side surfaces, respectively, of the cylindrical main body and a coupling section interconnecting the third and fourth electrode sections. The fourth electrode section is an inelastic conductor disposed in a position where the fourth electrode section does not contact the second electrode section. The conductor is provided outside the main body and conducts electricity between the second and fourth electrodes.

According to another aspect of the embodiments, there is provided a connector conducts electricity between electrode terminals located above and below the connector while the connector is being compressed and includes a main body, a first contact terminal and a second contact terminal. The main body is made of an elastic dielectric and is cylindrical in shape. The first contact terminal is an inelastic conductor including a first electrode section provided on the top surface of the cylindrical main body and a second electrode section connected to the first electrode section at the rim of the main body or inside the main body. The second contact terminal is an inelastic conductor including a third electrode section provided on the bottom surface of the cylindrical main body and a contact section connected to the third electrode section and always electrically in contact with the second electrode section at the rim of the main body or inside the main body.

It is to be understood that both the foregoing general description and the following detailed description and are exemplary and explanatory and are not restrictive of the embodiments, as claimed.

DESCRIPTION OF EMBODIMENTS

Embodiments of a connector according to the present invention and an interposer using the connector will be described below with reference to the attached drawings with respect to specific practical examples.

FIG. 1Aillustrates an interposer2interposed between a circuit board3and an IC package1.FIG. 1Bis a side view of the circuit board3and the IC package1, including a cross-sectional view of the interposer2. Input and output terminals (electrodes)4are arranged in a grid array on the back side of the IC package1. In the region in the circuit board where the IC package is to be mounted, terminal (electrode) traces6are formed in locations opposed to the input and output terminals4. Although omitted from the figures, a pattern of circuits and electronic components to be connected to the terminal traces6are provided on the circuit board3.

The interposer2is designed to be attached between the IC package1and the circuit board3to interconnect the input and output terminals4on the back side of the IC package1to the corresponding terminal traces6on the circuit board3. The interposer2is a thin high-terminal-density connector in which through-holes9corresponding to the input and output terminals4arranged in a grid array of an IC package1are provided in a sheet8of insulating material (hereinafter referred to as the interposer substrate) and connectors5are inserted in the through-holes9. The connectors5may have the same length and serve as an electric conductor that conducts electricity between both surfaces of the interposer substrate8.

When such an interposer2is used, the interposer2is typically attached inside a socket7as illustrated inFIG. 1C. The socket7is mounted onto a circuit board3by soldering or otherwise. The socket7allows the IC package1to be readily attached to and detached from the circuit board3.

Since the connectors5are sandwiched and compressed between the input and output terminals4on the back surface of the IC package1and the terminal traces6on the circuit board3, the connectors5are designed to be elastic to contract under the pressures from above and below while conducting electricity between the terminals above and below the connectors5.

FIG. 2Aillustrates a configuration of a connector10of a first exemplary embodiment of the present invention which is used as the connectors5illustrated inFIGS. 1A to 1C. The connector10of the first exemplary embodiment includes a cylindrical main body11made of an elastomer which is an elastic dielectric and two contact terminals12and17fixed to the main body11. The contact terminals12and17are made of an inelastic conductor, for example a metal. The contact terminal fixed onto the top surface of the main body1is herein referred to as the first contact terminal12and the contact terminal fixed onto the bottom surface as the second contact terminal17.

The first contact terminal12is attached across the edge between the top surface11T and the side surface11S of the main body11and has a protruding first electrode12A at the top surface11T and a protruding second electrode12B at the side surface11S. A strip-shaped coupling section is provided between the first and second electrodes12A and12B. The second contact terminal17is attached across the edge between the bottom surface11B and the side surface11S of the main body11and has a protruding third electrode17A at the bottom surface11B and a protruding fourth electrode17B at the side surface. A strip-shaped coupling section is provided between the third and fourth electrodes17A and17B.

The first and second contact terminals12and17are provided on the main body11along the plane passing through the central axis of the main body11. The second electrode12B and the fourth electrode17B are not in contact with each other but at a distance from each other. The first and second contact terminals12and17may be fixed to the main body11by using an adhesive or by providing protruding needles on the bottom surfaces of the first and second contact terminals12and17and inserting the needles into the main body11. While the first and second contact terminals12and17are thin strips in the first exemplary embodiment, the shape of the first and second contact terminals12and17is not limited to this. Each of the first and second contact terminals12and17may be of any shape having electrodes, one at an end surface and the other at the side surface of the main body11. Also, the first and second contact terminals12and17do not necessarily need to be in the same plane.

A conductor that electrically interconnects the second electrode12B and the fourth electrode17B needs to be provided outside the main body11. Therefore, to incorporate the connector10into an interposer substrate8as illustrated inFIG. 1, a conducting wall13is formed on the inner wall of each hole9provided in the interposer substrate8. Since the main body11in the exemplary embodiment is cylindrical and may rotate about its axis line, the conducting wall13is provided on the entire inner wall of the hole9. If an anti-rotation element is provided between the main body11and the inner wall of the hole9, the conducting wall13does not need to be provided on the entire inner wall. If the connector10is used singly, the connector10may be used in conjunction with a sleeve18as illustrated inFIG. 2B. The sleeve18may be made of a metal.

FIG. 2Cillustrates the connector10illustrated inFIG. 2Ainserted in a hole9provided in the interposer substrate8to form an interposer2. The same connectors10inFIG. 2Care arranged in a grid array in the interposer2as illustrated inFIG. 1A. The interior diameter of the hole9and the interior diameter of the sleeve18illustrated inFIG. 2Bare greater than the sum of the diameter of the main body11and the height of the protruding second electrode12B or fourth electrode17B. Accordingly, when the connector10is not connected to external electrodes above and below the connector10, it is possible that the second electrode12B and the fourth electrode17B do not contact the conducting wall13.

However, when the interposer2is inserted between an IC package1and a circuit board3and the connector10is compressed to interconnect an input and output terminal4and a terminal trace6as illustrated inFIG. 2D, the second electrode12B and the fourth electrode17B come into contact with the conducting wall13. This is because the compressed main body11expands widthwise to press the second electrode12B and the fourth electrode17B against the conducting wall13to bring them into contact with the conducting wall13. The interior diameter of the hole9and the interior diameter of the sleeve18are chosen so as to allow the second electrode12B and the fourth electrode17B to be pressed against and come into contact with the conducting wall13when the main body11is inserted between an IC package1and a circuit board3and compressed.

As has been described above, in the connector10of the first exemplary embodiment and the interposer2incorporating the connector10, the main body11made of an elastomer receives a compression force applied to the connector10and the first and second metal terminals12and17provide electrical pathways during conduction. Accordingly, a low constant resistance may be ensured during conduction in the connector10of the first exemplary embodiment and the interposer2incorporating the connector10. As variations of the connector10, a configuration illustrated inFIGS. 3A and 3Band a configuration illustrated inFIGS. 3C and 3Dare possible in which the second electrode12B and the fourth electrode17B are brought into contact with the conducting wall13while the connector10is not connected to electrode terminals above and below the connector10.

In the configuration illustrated inFIGS. 3A and 3B, a flange14is provided around the rim of the main body11in the center of the length of the main body11. In the configuration, the height of the flange14allows the second electrode12B and the fourth electrode17B to be always kept in contact with the conducting wall13. Since spaces are provided over and under the flange14, the main body11inserted and compressed between an IC package1and a circuit board3may be safely deformed.

In the configuration illustrated inFIGS. 3C and 3D, a semispherical protrusion15is provided on the rim of the main body11in the center of the length of the main body11on the side opposite from the second and fourth electrodes12B and17B. In the configuration, the height of the protrusion15allows the second and the fourth electrodes12B and17B to be always kept in contact with the conducting wall13. Since spaces are provided around the protrusion15, the main body11inserted and compressed between an IC package1and a circuit board3may be safely deformed.

FIG. 4Aillustrates a configuration of a connector10of a second exemplary embodiment of the present invention that is used in place of each of the connectors5illustrated inFIGS. 1A to 1C. The connector10of the second exemplary embodiment is similar to the connector10of the first exemplary embodiment with the only difference being the shape of the main body11made of an elastomer which is an elastic dielectric. The shape of first and second contact terminals12and17are almost the same as those of the first exemplary embodiment and therefore the same sections as those of the first exemplary embodiment are labeled the same reference numerals and description of the sections will be omitted. Only differences from the first exemplary embodiment will be described.

In the second exemplary embodiment, the main body11has the shape of a quadrangular prism with a square horizontal cross section. Accordingly, the holes9provided in an interposer substrate8are square in shape. Since the hole9is square, the connector10does not rotate about its axis line in the hole9. Therefore, the conducting wall13needs only to be provided on the side of the hole9that faces the first and second contact terminals12and17.

The length of the hole9in the X direction is greater than the sum of the corresponding length of the main body11in the X direction and the height of the protruding second electrode12B or fourth electrode17B. The length of the hole9in the Y direction is greater than the corresponding length of the main body11in the Y direction. Accordingly, when the connector10is not connected to external electrodes above and below the connector10, it is possible that the second electrode12B and the fourth electrode17B do not contact the conducting wall13. The length of the hole9in the X and Y directions is chosen so as to allow the second electrode12B and the fourth electrode17B to be pressed against and come into contact with the conducting wall13when the main body11is inserted and compressed between an IC package1and a circuit board3and deformed.

As variations of the connector10, a configuration illustrated inFIGS. 4B and 4Cand a configuration illustrated inFIG. 4Dare possible in which the second electrode12B and the fourth electrode17B are brought into contact with the conducting wall13while the connector10is not connected to external electrodes above and below the connector10.

In the configuration illustrated inFIGS. 4B and 4C, a curved bulge16is formed at the main body11on the side opposite from the side facing the conducting wall13of the main body11. While the bulge16is curved along the length of the main body11in the variation, the curved bulge may be curved along the width of the main body. Alternatively, a spherical surface may be provided instead of the curved bulge. In this configuration, the height of the bulge16allows the second electrode12B and the fourth electrode17B to be always kept in contact with the conducting wall13. Since the curved bulge16comes into line contact with the wall of the hole9, spaces are provided on both sides of the line of contact and therefore the main body11inserted and compressed between an IC package1and a circuit board3may be safely deformed. The same applies to a spherical bulge16.

In the configuration illustrated inFIG. 4D, two narrow raised strips16A are provided instead of the curved bulge16illustrated inFIGS. 4B and 4C. The rim of each of the raised strips16A is curved like the curved surface of the bulge16. In this configuration, the height of the raised strips16A allows the second electrode12B and the fourth electrode17B to be always kept in contact with the conducting wall13. Since spaces are provided around the raised strips16A, the main body11inserted and compressed between an IC package1and a circuit board3may be safely deformed.

FIG. 5Aillustrates a configuration of a connector10of a third exemplary embodiment of the present invention that is used in place of each of the connectors5illustrated inFIGS. 1A to 1C. The connector10of the third exemplary embodiment differs from the connector10of the second exemplary embodiment only in that the shape of a horizontal cross-section is rectangular instead of square. The first and second contact terminals12and17are identical in shape to those in the second exemplary embodiment and therefore the same sections as those in the second exemplary embodiments are labeled the same reference numerals and the description of the sections will be omitted. Only differences from the second exemplary embodiment will be described.

The main body11of the second exemplary embodiment has the shape of a quadrangular prism having a square horizontal cross-section. Accordingly, the holes9provided in the interposer substrate8are also square in shape. On the other hand, the main body11in the third exemplary embodiment has the shape of a quadrangular prism having a rectangular horizontal cross-section. Accordingly, the holes9provided in an interposer substrate8are rectangular in shape. In this case, the length of a hole9in the W direction is equal to the sum of the corresponding length of the main body11in the W direction and the height of the protruding second electrode12B or fourth electrode17B. The length of the hole9in the Z direction is well greater than the corresponding length of the main body11in the Z direction so that spaces are provided between the main body11and the wall of the hole9.

Accordingly, the second electrode12B and the fourth electrode17B come into contact with the conducting wall13while the connector10is not connected to external electrodes located above and below the connector10. In this configuration, when the main body11is inserted and compressed between an IC package1and a circuit board3, deformation of the main body11is allowed in the spaces in the Z direction.

If the holes9are arranged diagonally as illustrated inFIG. 5B, the pitch between adjacent holes9increases by a factor of1.4as illustrated inFIG. 5Band therefore larger substrate area may be used in designing the interposer.

FIG. 6Aillustrates a configuration of a connector20of a fourth exemplary embodiment of the present invention which is used as each of the connectors5illustrated inFIGS. 1A to 1C. The connector20of the fourth exemplary embodiment differs from the connectors10of the first to third exemplary embodiments in that the conductor outside the main body11is omitted but first and second contact terminals12and22are always electrically interconnected even when the connector20is not connected to external electrodes located above and below the connector20.

Therefore, while the first contact terminal12of the connector20of the fourth exemplary embodiment is identical in shape to the first contact terminal12of the first exemplary embodiment, the second contact terminal22is significantly different in shape from the second contact terminal17of the first exemplary embodiment. The same components in the fourth exemplary embodiment are labeled the same reference numerals in the fourth exemplary embodiment as those described with respect to the first exemplary embodiment and the description of those components will be omitted from the following description. Only differences from the first exemplary embodiment will be described.

The second contact terminal22in the fourth exemplary embodiment is attached across the edge between the bottom surface11B and the side surface11S of the main body11. A protruding third electrode22A is provided on the bottom surface11B and a receiving section22B extends from the side surface to the first contact terminal12with a predetermined distance away from the main body11. The distance between the receiving section22B and the main body11is equal to the distance from the side surface of the main body11to the tip of a protruding second electrode12B. Accordingly, a portion of the receiving section22B near the tip of the receiving section22B is electrically connected to the protruding second electrode12B of the first contact terminal12. The receiving section22B may be of a plate shape or of a curved shape having a concave on the main body11side that receives the protruding second electrode12B of the first contact terminal12as illustrated inFIG. 6B.

Each of holes9provided in an interposer substrate8in the fourth exemplary embodiment may have any shape and size that may accommodate the main body11and the first and second contact terminals12and22. This is because the first and second contact terminals12and22are always electrically interconnected and therefore a conducting wall does not need to be provided in the hole9.

In the case of the connector20of the fourth exemplary embodiment, when the connector20is connected with external electrodes located above and below the connector20, the main body11is compressed and the protruding second electrode12B of the first contact terminal12slides on the receiving section22B of the second contact terminal22. In the sliding, the compression expands the main body11outward, which presses the protruding second electrode12B of the first contact terminal12outward and enhances the contact between the second electrode12B and the receiving section22B of the second contact terminal22.

FIG. 7Aillustrates a configuration of a connector20of a fifth exemplary embodiment of the present invention which is used as each connector5illustrated inFIGS. 1A to 1C. The connector20of the fifth exemplary embodiment differs from the connector20of the fourth exemplary embodiment in that first and second contact terminals23and24are always in contact with each other inside the main body11. For the purpose of the connection, a vertical conducting hole19is provided in the main body11.

The first contact terminal23in the fifth exemplary embodiment has a protruding first electrode23A on the top surface11T of the main body11and a rod section23C extending from under the first electrode23A into the conducting hole19. A spherical section23B, which is a second electrode section, is at the tip of the rod section23C. The second electrode section may have a protruding shape instead of a spherical shape. The second contact terminal24has a protruding third electrode24A on the bottom surface11B of the main body11and a cylindrical section24B, which is a fourth electrode section extending from the bottom surface of the third electrode24A into the conducting hole19. The spherical section23B, which is the second electrode section, is placed in the internal space near the tip of the cylindrical section24B and is in contact with the interior surface of the cylindrical section24B. If the second electrode section has a protruding shape, the tip of the protrusion may be brought into contact with the interior surface of the cylindrical section24B.

Holes9provided in an interposer substrate8in the fifth exemplary embodiment may have any shape and size that may accommodate the main bodies11. This is because the first and second contact terminals23and24are always electrically interconnected and a conducting wall does not need to be provided in the holes9in the fifth exemplary embodiment, like the fourth exemplary embodiment.FIG. 7Billustrates an exemplary embodiment of the interposer substrate8in which holes9are circular in shape.

In the case of the connector20of the fifth exemplary embodiment, when the connector20is connected with external electrodes located above and below the connector20, the main body11is compressed and the spherical section23B of the first contact terminal23slides on the internal surface of the cylindrical section24B of the second contact terminal24. In the sliding, the compression expands the main body11outward and therefore the cylindrical section24B of the second contact terminal24is pressed inward, which enhances the contact between the cylindrical section24B and the spherical section23B of the first contact terminal23.

When an interposer2incorporating the connectors20of any of the fourth and fifth exemplary embodiments is used, the interposer2may be attached in the socket illustrated inFIG. 1C. The first and second contact terminals in the interposer2incorporating the connectors20of any of the fourth and fifth exemplary embodiments are directly in contact with each other. Therefore, the interposer2of any of the fourth and the fifth exemplary embodiments is capable of improving the signal quality and reliability of (removable) stack mounting of a fast, large-sized IC package and providing an approach to developing a faster and denser device.

The present invention has been described in detail specifically with reference to preferred embodiments thereof. To facilitate the understanding of the present invention, specific modes of the present invention will be given below.