Contact member, connecting method of the contact member, and socket

A contact member inserted in a piercing hole of a socket provided between a first contacted member and a second contacted member facing each other, the contact member includes a first contact part configured to come in contact with a first pad formed in the first connected member; a second contact part configured to come in contact with a second pad formed in the second connected member; and a spiral cylindrical part formed in a spiral manner with respect to an axial line connecting the first pad and the second pad, the spiral cylindrical part having one end formed in a large diameter curved part having the first contact part, the spiral cylindrical part having another end formed in a small diameter curved part having the second contact part; the spiral cylindrical part having an external circumferential surface coming in contact with an inside wall of the piercing hole.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to contact members, connecting methods of the contact members, and sockets. More specifically, the present invention relates to a contact member configured to electrically connect a first connected member and a second connected member facing each other, a connecting method of the contact member, and a socket.

2. Description of the Related Art

Contact members are electrically connected to plural electrodes of an electronic device, an inspection device, or a socket for an IC package in a state where the contact members are arranged to correspond to the electrodes. Here, the socket for the IC package is configured to mount in an exchangeable manner an LGA (Land Grid Array) type or a BGA (Ball Grid Array) type IC package on a printed wiring board.

A telescopic contact member is suggested in Japanese Laid-Open Patent Application Publication No. 2005-129428. The telescopic contact member suggested in Japanese Laid-Open Patent Application Publication No. 2005-129428 is inserted into a piercing hole of a socket (board) so that an external circumference of the socket is engaged with an inside wall of the socket. A contact part of the center part of the contact member projects upward and downward from the socket.

This contact member has a spiral spring structure where a belt shaped conductive metal member is triple-wound. Therefore, when the contact part of the center part of the contact member comes in contact with an electrode of an electronic device or a printed wiring board, the spiral wound conductive metal member is compressed in up and down directions and a contact pressure is applied to the electrode based on a reaction force.

However, because the above-mentioned contact member has a structure where the belt shape conductive metal member is triple-wound, electronic signals flow in a longitudinal direction (circumferential direction) of the spiral shaped conductive metal member.

Accordingly, inductance at an electric current-carrying time is increased. Furthermore, because a large number of the contact members corresponding to the number of the electrodes is provided, the sum of the entire inductance is greatly increased.

SUMMARY OF THE INVENTION

Accordingly, embodiments of the present invention may provide a novel and useful contact member, a connecting method of the contact member, and a socket solving one or more of the problems discussed above.

More specifically, the embodiments of the present invention may provide a contact member inserted in a piercing hole of a socket provided between a first contacted member and a second contacted member facing each other, the contact member including:

a first contact part configured to come in contact with a first pad formed in the first connected member;

a second contact part configured to come in contact with a second pad formed in the second connected member; and

a spiral cylindrical part formed in a spiral manner with respect to an axial line connecting the first pad and the second pad, the spiral cylindrical part having one end formed in a large diameter curved part having the first contact part, the spiral cylindrical part having another end formed in a small diameter curved part having the second contact part; the spiral cylindrical part having an external circumferential surface coming in contact with an inside wall of the piercing hole;

wherein a compression load in the axial line direction is applied to the first contact part and the second contact part so that the small diameter curved part situated inside the spiral cylindrical part is deformed outwardly and comes in contact with the large diameter curved part situated outside the small diameter curved part, and thereby the first pad and the second pad are electrically connected to each other with a shortest length.

The embodiments of the present invention may provide a connecting method of a contact member, the contact member includinga first contact part configured to come in contact with a first pad formed in a first connected member;a second contact part configured to come in contact with a second pad formed in a second connected member; anda spiral cylindrical part formed in a spiral manner with respect to an axial line connecting the first contact part and the second contact part, the spiral cylindrical part having one end configured to hold the first contact part, another end configured to hold the second contact part, and an external circumferential surface coming in contact with an inside wall of the piercing hole;

the connecting method including:

a step of inserting the spiral cylindrical part into the piercing hole of the socket so that the external circumferential surface of the spiral cylindrical part comes in contact with the inside wall of the piercing hole, the first contact part projects at one side of the socket, and the second contact part projects at another side of the socket;

a step of making the first contact part come in contact with a first pad formed in the first connected member;

a step of making the second contact part come in contact with a second pad formed in the second connected member; and

a step of applying a compression load in the axial line direction to the first contact part and the second contact part so that the small diameter curved part situated inside the spiral cylindrical part is deformed outwardly and comes in contact with the large diameter curved part situated outside the small diameter curved part, and thereby the first pad and the second pad are electrically connected to each other with a shortest length.

The embodiments of the present invention may provide a socket provided between a first contacted member and a second contacted member facing each other, the socket having a piercing hole where a contact member is inserted, the piercing hole piercing between the first contacted member and the second contacted member,

the contact member including:

a first contact part configured to come in contact with a first pad formed in the first connected member;

a second contact part configured to come in contact with a second pad formed in the second connected member; and

a spiral cylindrical part formed in a spiral manner with respect to an axial line connecting the first pad and the second pad, the spiral cylindrical part having one end formed in a large diameter curved part having the first contact part, the spiral cylindrical part having another end formed in a small diameter curved part having the second contact part; the spiral cylindrical part having an external circumferential surface coming in contact with an inside wall of the piercing hole;

wherein a compression load in the axial line direction is applied to the first contact part and the second contact part so that the small diameter curved part situated inside the spiral cylindrical part is deformed outwardly and comes in contact with the large diameter curved part situated outside the small diameter curved part, and thereby the first pad and the second pad are electrically connected to each other with a shortest length.

According to the embodiments of the present invention, a compression load in an axial line is added to the first contact part and the second contact part. As a result of this, the small diameter curved part situated inside of a spiral cylindrical part is deformed outwardly so as to come in contact with a large diameter curved part situated outside the small diameter part. Because of this, it is possible to electrically connect the first pad and the second pad to each other with a shortest length. Hence, it is possible to make impedance at the time of mounting small and reduce electric loss.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description is given below, with reference to theFIG. 1throughFIG. 23Bof embodiments of the present invention.

First Embodiment

FIG. 1is an exploded perspective view of a socket50for an LGA type IC package using a contact member of a first embodiment of the present invention.FIG. 2is a side cross-sectional view showing the socket50in use.

Furthermore, the socket50for an IC package (hereinafter “socket50”) is provided under the board (a second connected member)20of the IC package10. In the socket50, plural contact members40are arranged in X and Y directions at designated pitches so as to face a connected surface formed in a lower surface of the board20.

In addition, a printed wiring board (a first connected member)70is provided under the socket50so that a connected surface situated at an upper side faces the socket50. A cover member80is provided above the IC package10so as to cover an upper surface of the IC chip30.

The socket50includes a base plate52and a frame54. The base plate52has a plane plate shaped configuration and is made of an insulation material such as a resin material. The frame54is provided so as to surround the base plate52.

The socket50is used when the IC package10is mounted on the printed wiring board70. The socket50is provided between the printed wiring board70and the IC package10so that an end part of the contact member40projecting to a lower surface of the IC package10and a second pad72formed on the printed wiring board70are electrically connected to each other.

The base plate52is supported by the rectangular shaped frame54so that an upper surface and a lower surface of the base plate52form horizontal surfaces. Circumferential edge parts in X and Y directions of the frame54having the rectangular shaped configuration are rigid.

In addition, piercing holes56are provided in the base plate52. The piercing holes56are arranged in the X and Y directions at designated pitches in the base plate52. The piercing holes56are arranged above plural second pads72attached to the printed wiring board70. The piercing holes56and the second pads72face each other so that axial lines passing through the centers in the up and down directions of the piercing holes56pass through the centers of the corresponding second pads72.

FIG. 3Ais an expanded view of a portion A shown inFIG. 2.FIG. 3Bis a plan view where the contact member40is inserted into the piercing hole56.

Referring toFIG. 3AandFIG. 3B, the contact member40is made of a metal material having conductivity and spring properties, such as phosphor bronze or stainless steel. The contact member40includes a spiral cylindrical part41, a large diameter curved part42, a second contact part43, a small diameter part41, and a first contact part45.

The spiral cylindrical part41is formed in a spiral shape and generates a spring force in the up and down directions (Z1and Z2directions). The large diameter curved part42is situated outside the spiral cylindrical part41and has a large radius of curvature. The second contact part43is formed at a lower end of the large diameter curved part42.

The small diameter curved part44is formed inside the large diameter curved part42and has a radius of curvature smaller than that of the large diameter curved part42. The first contact part45is formed at an upper end of the small diameter curved part44.

The contact members40are inserted into the corresponding piercing holes56of the base plate52. As a result, the external circumference of the large diameter curved part42comes in contact with an inside wall of the piercing hole56so that the spiral cylindrical part41is held in the piercing hole56due to friction based on contact pressure of the external circumferential surface of the large diameter curved part42. The small diameter part44is situated inside and separated from an internal circumference of the large diameter curved part42.

Furthermore, the second contact part43projects downward from the piercing hole56and the first contact part45projects upward from the piercing hole56. Because of this, when a compression load in the up and down directions is applied to the contact member40, an inclination angle of the spiral cylindrical part41becomes small in order to be changed to an angle close to a horizontal, and the small diameter curved part44is pushed down relative to the large diameter part42. Hence, the contact member40can be in contact in the up and down directions.

Here, steps of mounting the IC package10on the printed wiring board70are discussed.

As shown inFIG. 1andFIG. 2, first, the socket50is mounted on the printed wiring board70.

Next, the IC package10is provided inside the frame54of the socket50so as to be mounted on the base plate52.

Then, the cover member80is mounted on the IC package10.

After this, bolts90are inserted into engaging holes82formed at corner parts of the cover member80. In addition, the bolts90are inserted into engaging holes58formed at corner parts of the frame54of the socket50and engaging holes74of the printed wiring board70. Then, nuts91are screw-fixed to lower ends of the bolts90projecting through the lower surface of the printed wiring board70.

As a result of this, the components forming the mounting structure of the IC package10are connected to each other in a unified structure. The IC package10is sandwiched between the cover member80and the base plate52and mounted on the printed wiring board70via the socket50.

In this mounting structure, the first contact parts45formed at the upper end of the contact members40come in contact with corresponding first pads22(not shown inFIG. 1) formed on the lower surface of the board20. In addition, the second contact parts43formed at the lower end of the contact members40come in contact with the corresponding second pads72formed on the printed wiring board70.

As shown inFIG. 3AandFIG. 3B, when the compression load is applied to the contact member40in the up and down directions (Z1and Z2directions inFIG. 3A), the small diameter part44goes down and deforms to an expanded diameter side in a radial direction so that the small diameter curved part44comes in contact with an internal surface of the large diameter curved part42and electric conductivity can be established.

Furthermore, a projection46for connection having a semi-spherical shaped configuration (third contact part46) projects from the external circumference of the small diameter curved part44. This projection46for connection comes in point-contact with the internal circumference surface of the large diameter curved part42.

With this structure, the contact member40is shortened along a line connecting in the up and down directions the second contact part43of the large diameter curved part42and the first contact part45of the small diameter curved part44to each other.

Because of this, with this structure, plural first pads22and the corresponding second pads72are electrically connected to each other with shortest lengths. Here, the first pads22of the IC chip30come in contact with the corresponding first contact parts45formed at the upper end of the contact members40. The second pads72on the printed wiring board70come in contact with the second contact parts43formed at the lower ends of the contact members40. Because of this, in the contact member40, inductance at the time of mounting can be made small so that electrical loss can be reduced.

In addition, it is possible to separate the IC package10from the printed wiring board70by unscrewing the bolts90and the nuts91. As a result of this, because the compression load in the up and down directions in the contact member40is eliminated, the second contact part43and the first contact part45move vertically apart (are extended) again so that the projection46for connection provided at the small diameter curved part44is separated from the internal circumferential surface of the large diameter curved part42.

Here, a manufacturing method of the above-discussed contact member40is discussed with reference toFIG. 4AthroughFIG. 4B.

Here,FIG. 4Ais a front view showing the belt shaped member100in a state where the contact member40is expanded vertically.FIG. 4Bis a side view of the belt shaped member100.FIG. 5Ais a perspective view of the curved contact member40.FIG. 5Bis a plan view of the curved contact member40.

As shown inFIG. 4AandFIG. 4B, first, a metal plate working is applied to a plate made of a metal material having conductivity and spring properties, such as phosphor bronze or stainless steel. Alternatively, a belt shaped metal material wound in a roll is cut into parts having designated lengths. As a result of this, the belt shaped member100is formed. This belt shaped member100is the contact member40developed in a planar plate shape.

The height H and width B of the belt shaped member100are determined based on the diameter of the piercing hole56or the depth of the piercing hole56(namely, thickness of the base plate52).

In next step, the projection46for connection is formed on the belt shaped member100by a pressing process. The projection46for connection has a semi-spherical shaped configuration and the top of the projection46works as a contact part. A configuration other than the semi-spherical shaped configuration, for example, a trapezoidal shaped configuration or a conical shaped configuration, may be selected as the configuration of the projection46.

A position where the projection46is formed is in an area D where the overlapped large diameter curved part42and the small diameter curved part44face each other.

The area D is a rectangular shaped area and includes a circumferential direction area and a height direction area. Here, the circumferential direction area is an area where the small diameter curved part44is operated in the circumferential direction with respect to the large diameter curved part42, which is pressed and held by the internal circumferential surface of the piercing hole56. The height direction area is an area where the small diameter part44moves down due to the pressing load in the up and down directions. It is preferable to set the area D by considering a range of a process error.

In a next step, as shown inFIG. 5AandFIG. 5B, the belt shaped member100is curved in a spiral manner. At this time, the radius of curvature in a process for making the spiral is made small so that one end (right end inFIG. 4A) in a longitudinal direction of the belt shaped member100having the projection46has a small diameter.

In addition, the radius of curvature in a process for making the spiral is made large so that another end (left end inFIG. 4A) in the longitudinal direction of the belt shaped member100has a large diameter. In addition, the radius of curvature used in the process for making the spiral is set so that both ends in the longitudinal direction of the belt shaped member100overlap with different spiral diameters.

When the process for making the spiral is performed, the belt shaped member100is formed in a spiral manner in a diameter direction and in an inclined manner with a designated inclination angle relative to an axial direction. Therefore, it is possible to realize elastic deformation in the diameter direction and expansion and contraction in the axial direction of the belt shaped member100.

Because of this, when the process for making the spiral is applied to the belt shaped member100, for example, the belt shaped member100is curved in a roll in the circumferential direction (C direction inFIG. 4A) where an axial line L is a centerline. The axial line L is inclined at a designated angle (angle θ shown inFIG. 4A) relative to the belt shaped member100.

When the process for making the spiral is completed, a gap S is formed between a top part of the projection46and an internal circumferential surface of the large diameter curved part42. Because of this, the large diameter curved part42and the small diameter curved part44do not come in contact with each other. This gap S remains even where the contact member40is inserted in the piercing hole56of the socket50(base plate52).

Accordingly, as shown inFIG. 2, when the IC package10is mounted on the printed wiring board70using the socket50, in the contact member40inserted in the piercing hole56of the socket50, the large diameter curved part42and the small diameter curved part44are compressed in the up and down directions (Z1and Z2directions) by a compression load.

During a process where the spiral cylindrical part41is changed from being inclined to being horizontal, the small diameter part44goes down to the large diameter curved part42pressed and held by the internal circumferential surface of the piercing hole56and the small diameter part44deforms and the diameter of the small diameter part44increases outwardly. As a result of this, the projection46provided on the small diameter curved part44comes in point contact with the large diameter curved part42.

In addition, due to a spring force (elastic restoring force) based on an elastic deformation of the spiral cylindrical parts41, the first contact parts45of the contact members40are pressed by the corresponding first pads22of the board20. The second contact parts43of the contact members40are pressed by the corresponding second pads72provided on the printed wiring board70.

In other words, when mounted as shown inFIG. 3A, the spiral cylindrical part41of the contact member40is elastically deformed from being inclined to being substantially horizontal, so that contact pressure on the first pads22and the second pads72can be generated.

Next, a modified example 1 of the first embodiment of the present invention is discussed with reference toFIG. 6AandFIG. 6B. In the following explanation, parts that are the same as the parts discussed in the first embodiment of the present invention are given the same reference numerals, and explanation thereof is omitted.

Here,FIG. 6Ais an expanded view of the modified example 1 of the first embodiment of the present invention.FIG. 6Bis a plan view of the modified example 1 of the first embodiment of the present invention.

Referring toFIG. 6AandFIG. 6B, in the modified example 1, a conductive layer110extending in Z1and Z2directions is formed on the entire internal circumferential surface of the piercing hole54by a plating method. A through hole is formed in the conductive layer110. The conductive layer110is electrically connected to a wiring pattern120situated on an upper surface of the base plate52and a wiring pattern130situated on a lower surface of the base plate52.

Accordingly, when the IC package10is mounted on the printed wiring board70using the socket50, the first contact part45formed at the upper ends of the contact members40come in contact with the corresponding first pads22formed on the lower surface of the board20. The second contact parts43formed at the lower end of the contact members40come in contact with the corresponding second pads72formed on the printed wiring board70.

Thus, in the contact member40, by applying the compression load in the up and down directions (Z1and Z2directions), the small diameter curved part44goes down and deforms to the expanded diameter side in the radial direction and thereby the top part of the projection46of the small diameter curved part44comes in contact with the internal surface of the large diameter curved part42. As a result of this, electric conductivity can be established.

On the other hand, the large diameter curved part42comes in contact with the conductive layer110formed on an internal circumferential surface of the piercing hole56so that the contact member40inserted in the piercing hole56of the socket50is reset.

Furthermore, the small diameter curved part44goes down and the diameter of the small diameter curved part44expands outwardly. Hence, the projection46provided on the small diameter curved part44comes in point contact with the internal circumferential surface of the large diameter curved part42.

With this structure, the contact member40is securely shortened along a line connecting in the up and down directions the second contact part43of the large diameter curved part42to the first contact part45of the small diameter curved part44. The first pads22of the IC chip30are electrically connected to the wiring patterns120and130formed at the upper surface and the lower surface of the base plate52.

FIG. 7Ais an expanded view of a modified example 2 of the first embodiment of the present invention.FIG. 7Bis a plan view of the modified example 2 of the first embodiment of the present invention.

Referring toFIG. 7AandFIG. 7B, in the modified example 2, the conductive layer112extending in the Z1and Z2directions is formed on a part of the internal circumferential surface of the piercing hole56. The conductive layer112has a designated width in the circumferential direction. The conductive layer112is electrically connected to the wiring pattern120situated at an upper surface of the base plate52and the wiring pattern130situated at a lower surface of the base plate52.

In addition, an engaging groove55extending in the up and down directions is formed in the internal circumferential surface of the piercing hole54neighboring the conductive layer112. The engaging groove55is engaged with an engaging part42aprojecting outwardly from an end part of the large diameter curved part42. Because of this, when the engaging part42ais engaged with the engaging groove55, a position in the circumferential direction of the large diameter curved part42is fixed and movement in the circumferential direction of the large diameter curved part42is restricted.

The depth in the diameter direction of the engaging groove55is greater than a length projecting in the diameter direction of the engaging part42a. Because of this, the large diameter curved part42is held in contact with the conductive layer112.

Accordingly, when the IC package10is mounted on the printed wiring board70using the socket50, the first contact parts45of the contact members40come in contact with the corresponding first pads22of the board20. In addition, the second contact parts43of the contact members40come in contact with the second pads72on the printed wiring board70. Furthermore, the top part of the projection46of the small diameter curved part44comes in contact with the internal surface of the large diameter curved part42.

Thus, the electric conductivity between the second contact part43and the first contact part45can be established with a shortest length in the up and down directions (Z1and Z2directions).

In addition, the contact member40inserted in the piercing hole56of the socket50comes in contact with the conductive layer112formed on a art of the internal circumferential surface of the piercing hole56where the engaging part42aof the large diameter curved part42is engaged with the engaging groove55so as to be fixed in position.

As a result of this, the contact member40is securely shortened along a line connecting in up and down directions the second contact part43of the large diameter curved part42to the first contact part45of the small diameter curved part44. The first pads22of the IC chip30are electrically connected to the wiring patterns120and130formed at the upper surface side and the lower surface of the base plate52.

FIG. 8Ais an expanded view of a modified example 3 of the first embodiment of the present invention.

Referring toFIG. 8A, in a contact member401of a third modified example of the first embodiment of the present invention, when the IC package10is mounted on the printed wiring board70using the socket50, solder140is provided in the periphery of the second contact part43so that the second contact part43and the second pad72are fixed to each other where the second contact part43of the contact member40comes in contact with the second pad72on the printed wiring board70.

A part configured to fix the second contact part43and the second pad72to each other may be a part other than the solder140such as an adhesive.

With this structure, because the large diameter curved part42having the second contact part43is unified with the second pad72by the solder140, it is possible to improve the connection strength and securely establish an electrical connection.

In addition, at the time of mounting, when a load is applied to the first contact part45of the small diameter curved part44, the contact member40is securely pressed by the reaction force from the second pad72.

As a result of this, the top part of the projection46of the small diameter curved part44comes in contact with the internal surface of the large diameter curved part42so that the electric conductivity between the second contact part43and the first contact part45can be established with a shortest length in the up and down directions (Z1and Z2directions).

Because of this, in the contact member401, inductance at the time of mounting can be made small so that electrical loss can be reduced.

FIG. 8Bis an expanded view of a modified example 4 of the first embodiment of the present invention.

Referring toFIG. 8B, in a contact member402of the modified example 4, a projection43aand a projection45aare provided on the second contact part43and the first contact part45, respectively. The projection43aand the projection45ahaving spherical configurations are made of conductive materials such as solder.

Because the projection43aand the projection45ahave the spherical configurations, contact areas with the first pad22and the second pad72are expanded so that an electrical connection can be securely made.

In addition, because the projection43aand the projection45aare made of metal materials which are softer than the first pad22and the second pad72, contact parts of the projection43aand the projection45apressed to the surfaces of the first pad22and the second pad72are deformed so as to have planar configurations.

Because of this, it is possible to securely connect the first pad22and the second pad72of the contact member402.

FIG. 8Cis an expanded view of a modified example 5 of the first embodiment of the present invention.

Referring toFIG. 8C, in a contact member403of the modified example 5 of the first embodiment, the spiral cylindrical part41A is made of an insulation material having spring properties such as a resin material. A first conductive member (large diameter curved part)42A and a second conductive member (small diameter curved part)44A are provided at corresponding ends in the circumferential direction of the spiral cylindrical part41A. The first conductive member (large diameter curved part)42A is formed in a body with the second contact part43. The second conductive member (small diameter curved part)44A is formed in a body with the first contact part45.

The first conductive member42A and the second conductive member44A are made of conductive materials such as phosphor bronze or stainless steel. The first conductive member42A and the second conductive member44A are curved based on radii of curvature corresponding to the large diameter curved part and the small diameter curved part.

The spiral cylindrical part41A made of the insulation material and the first conductive member42A and the second conductive member44A made of the conductive material are connected in a body by an insert molding method or an adhesive, for example.

The contact member403is securely shortened by the projection46being along a line connecting in the up and down directions the second contact part43of the first conductive member42A to the first contact part45of the second conductive member44A to each other.

Because of this, the mounted plural first pads22and the corresponding second pads72are electrically connected to each other with shortest lengths. Here, the first pads22of the IC chip30come in contact with the second contact parts43formed at the upper end of the contact member40. The second pads72on the printed wiring board70come in contact with the second contact parts43formed at the lower end of the contact member40. Because of this, in the contact member403, inductance at the time of mounting can be made small so that electrical loss can be reduced.

Second Embodiment

FIG. 9is an expanded view of a second embodiment of the present invention.

Referring toFIG. 9, in a contact member404of the second embodiment, plural projections (third contact parts)46project from the external circumferential part of the small diameter curved part44. These projections46have hemispherical configurations and are provided in the up and down directions (Z1and Z2directions) and a circumferential direction with designated spaces.

In this example, three projections46are provided in the up and down directions and two lines of the projections46are provided in the circumferential direction. Plural projections46have the same diameter lengths, have the same projection heights and come in point-contact with the internal circumferential surface of the large diameter curved part42.

When the IC package10is mounted on the printed wiring board70using the socket50, in contact member40inserted in the piercing hole56of the socket50, the large diameter curved part42and the small diameter curved part44are compressed in the up and down directions (Z1and Z2directions) by a compression load.

During a process where the spiral cylindrical part41is changed from being inclined to being horizontal, the small diameter part44goes down to the large diameter curved part42pressed and held by the internal circumferential surface of the piercing hole56and a diameter of the small diameter part44deforms outwardly. As a result of this, the projection46provided on the small diameter curved part44comes in point contact with the large diameter curved part42.

Thus, even if dimensional unevenness is generated in a gap S between the large diameter curved part42and plural projections46, any of the plural projections46can be securely brought into contact with the internal circumferential surface of the large diameter curved part42.

The contact member404is securely shortened by the projections46along a line connecting in the up and down directions the second contact part43of the large diameter curved part42to the first contact part45of the small diameter curved part44.

Because of this, the mounted plural first pads22and the corresponding second pads72are electrically connected to each other with shortest lengths. Here, the first pads22of the IC chip30come in contact with the first contact part45formed at the upper end of the contact member404. The second pads72on the printed wiring board70come in contact with the second contact parts43formed at the lower end of the contact member404. Because of this, in the contact member404, inductance at the time of mounting can be made small so that electrical loss can be reduced.

Here, a manufacturing method of the above-mentioned contact member404is discussed with reference toFIG. 10AthroughFIG. 11B.

FIG. 10Ais a front view showing a belt shaped member100A where a contact member40A is expanded.FIG. 10Bis a side view of the belt shaped member100A.FIG. 11Ais a perspective view of a curved contact member404.FIG. 11Bis a plan view of the curved contact member404.

As shown inFIG. 10AandFIG. 10B, first, metal plate working is applied to a plate made of a metal material having conductivity and spring properties, such as phosphor bronze or stainless steel. Alternatively, a belt shaped metal material wound in a roll is cut into parts having designated lengths. As a result of this, the belt shaped member100A is formed.

The height H and width B of the belt shaped member100A are determined based on the diameter of the piercing hole56or the depth of the piercing hole56(namely, thickness of the base plate52).

In the next step, plural projections46are formed on the belt shaped member100A by a pressing process. The projections46have semi-spherical shaped configurations and the top of the projections46work as contact parts. A configuration other than the semi-spherical shaped configuration, for example, a trapezoidal shaped configuration or a conical shaped configuration, may be selected as the configuration of the projection46.

Positions where plural projections46are formed are in an area D where overlapped large diameter curved part42and small diameter curved part44face each other.

The area D is a rectangular shaped area and includes a circumferential direction area and a height direction area. Here, the circumferential direction area is an area where the small diameter curved part44is operated in the circumferential direction with respect to the large diameter curved part42, which is pressed and held by the internal circumferential surface of the piercing holes56. The height direction area is an area where the small diameter part44moves down due to the compression load in the up and down directions. It is preferable to set the area D by considering a range of a process error.

Accordingly, the number of the projections46is not limited to six of this example but may be two through five or more than six. The size of the projection46may be properly selected so that the projections46are situated in the area D.

In a next step, as shown inFIG. 11AandFIG. 11B, the belt shaped member100A is curved in a spiral manner. A process for spiraling in this example is the same as that in the first embodiment of the present invention and therefore the explanation thereof is omitted.

When the process for making the spiral is completed, gaps S are formed between top parts of the projections46and internal circumferential surfaces of the large diameter curved part42. Because of this, the large diameter curved part42and the small diameter curved part44do not come in contact with each other. This gap S remains even where the contact member404is inserted in the piercing hole56of the socket50.

Third Embodiment

FIG. 12is an expanded view of a third embodiment of the present invention.

Referring toFIG. 12, in a contact member405of a third embodiment of the present invention, a contactor (third contact part)47projects from the external circumferential part of the small diameter curved part44.

The contactor47has a plate spring shaped configuration. A head end part47aof the contactor47inclines outwardly from the external circumferential part of the small diameter curved part44.

The head end part47aof the contactor47is bent and a bent part of the head end part47acloses to the internal circumferential surface of the large diameter curved part42.

When the IC package10is mounted on the printed wiring board70by using the socket50, in a contact member405inserted in the piercing hole56of the socket50, the large diameter curved part42and the small diameter curved part44are compressed in the up and down directions (Z1and Z2directions) by a compression load.

During a process where the spiral cylindrical part41is changed from being inclined to being horizontal, the small diameter part44goes down to the large diameter curved part42pressed and held by the internal circumferential surface of the piercing hole56and the diameter of the small diameter part44deforms to the outside. As a result of this, the projection46provided on the small diameter curved part44comes in point contact with the large diameter curved part42.

Because the contactor47is formed by a spring having a cantilever beam structure, the head end part47acomes in contact with the internal circumferential surface of the large diameter curved part42and is elastically deformed so that the spring force is transmitted to the inner circumferential surface of the large diameter curved part42. In other words, the contactor47generates a pressing force in a direction where the large diameter curved part42and the small diameter curved part44are separated from each other. As a result of this, the contact pressure between the large diameter curved part42and the small diameter curved part44can be secured.

The contact member405is securely shortened along a line connecting in up and down directions the second contact part43of the large diameter curved part42to the first contact part45of the small diameter curved part44.

Because of this, the mounted first pads22and the corresponding second pads72are electrically connected to each other with shortest lengths. Here, the first pads22of the IC chip30come in contact with the first contact part45formed at the upper end of the contact member405. The second pads72on the printed wiring board70come in contact with the second contact parts43formed at the lower end of the contact member405. Because of this, in the contact member405, inductance at the time of mounting can be made small so that electrical loss can be reduced.

Because the contactor47has the plate spring structure, even if dimensional unevenness is formed between the large diameter curved part42and the contactor47, the contactor47is elastically deformed in a radius direction so that the head end part47acan securely come in contact with the internal circumferential surface of the large diameter curved part42.

Although the contactor47extends in the up and down directions in this example, the present invention is not limited to this. For example, the contactor47may be provided in a horizontal direction (where its longitudinal direction is a circumferential direction).

Here, a manufacturing method of the above-mentioned contact member405is discussed with reference toFIG. 13AthroughFIG. 14B.

FIG. 13Ais a front view showing a belt shaped member100B where a contact member405is expanded.FIG. 13Bis a side view of the belt shaped member100B.FIG. 14Ais a perspective view of the curved contact member405.FIG. 14Bis a plan view of the curved contact member405.

As shown inFIG. 13AandFIG. 13B, first, metal plate working is applied to a plate made of a metal material having conductivity and spring properties, such as phosphor bronze or stainless steel. Alternatively, a belt shaped metal material wound in a roll is cut into parts having designated lengths. As a result of this, the belt shaped member100B is formed.

The height H and width B of the belt shaped member100B are determined based on the diameter of the piercing hole56or the depth of the piercing hole56(namely, thickness of the base plate52).

In a next step, a pressing process is applied to the belt shaped member100B so that the contactors47A are bent. The contactor47is bent where a base part47bis inclined at a designated angle relative to the surface of the belt shaped member100B. In addition, the contactor47is bent downward so that a curving part of the head end part47ais a top part. Furthermore, the head end part47aof the contactor47extends upward, namely in the Z1direction.

A processing position of the contactor47is formed so as to be in the area D where the large diameter curved part42and the small diameter curved part44face each other.

In a next step, as shown inFIG. 14AandFIG. 14B, the belt shaped member100B is curved in a spiral manner. A process for curving in this example is the same as that in the first and second embodiments of the present invention and therefore the explanation thereof is omitted.

When the process for making the spiral is completed, a gap S is formed between the head end part47aof the connector47and an internal circumferential surface of the large diameter curved parts42. Because of this, the large diameter curved part42and the small diameter curved part44do not come in contact with each other. This gap S remains even where the contact member405is inserted in the piercing hole56of the socket50.

Here, a first modified example of the third embodiment of the present invention is discussed with reference toFIG. 15.

FIG. 15is an expanded view of the first modified example of the third embodiment of the present invention.

Referring toFIG. 15, in the contact member406of the first modified example of the second embodiment, a pair of contactors (third contact part)47A and47B project from the external circumferential surface of the small diameter curved part44in the up and down directions. The contactors47A and47B have plate spring shaped configurations. The head end part47ainclines outside the external circumference of the small diameter curved part44.

Although the pair of the contactors47is provided at the external circumference of the small diameter curved part44in this example, the present invention is not limited to this. For example, the contactors47A and47B may be provided in parallel or plural contactors47may be provided in a horizontal direction (where a longitudinal direction is a circumferential direction).

The contactors47A and47B are provided in a symmetrical manner in the up and down directions. In addition, the head end parts47aof the contactors47A and47B are bent and bent parts are close to the internal circumferential surface of the large diameter curved part42.

Because of this, even if dimensional unevenness is generated in a gap S between the large diameter curved part42and plural projections46, one of the contactors47can securely come in contact with the internal circumferential surface of the large diameter curved part42.

The contactors47A and47B generate a pressing force in a direction where the large diameter curved part42and the small diameter curved part44are separated from each other. As a result of this, the contact pressure between the large diameter curved part42and the small diameter curved part44can be secured by the contactors47A and47B.

The contact member406is securely shortened by the contactors47A and47B being along a line connecting in the up and down directions the second contact part43of the large diameter curved part42to the first contact part45of the small diameter curved part44.

Because of this, the mounted plural first pads22and the corresponding second pads72are electrically connected to each other with shortest lengths. Here, the first pads22of the IC chip30come in contact with the second contact part45formed at the upper end of the contact member406. The second pads72on the printed wiring board70come in contact with the second contact parts43formed at the lower end of the contact member406. Because of this, in the contact member406, inductance at the time of mounting can be made small so that electrical loss can be reduced.

Here, a manufacturing method of the above-mentioned contact member406is discussed with reference toFIG. 16AthroughFIG. 17B.

FIG. 16Ais a front view showing a belt shaped member100C where the contact member406is expanded.FIG. 16Bis a side view of the belt shaped member100C.FIG. 17Ais a perspective view of the curved contact member406.FIG. 17Bis a plan view of the curved contact member406.

As shown inFIG. 16AandFIG. 16B, first, metal plate working is applied to a plate made of a metal material having conductivity and spring properties, such as phosphor bronze or stainless steel. Alternatively, a belt shaped metal material wound in a roll is cut into parts having designated lengths. As a result of this, the belt shaped member100C is formed.

The height H and width B of the belt shaped member100C are determined based on the diameter of the piercing hole56or the depth of the piercing hole56(namely, thickness of the base plate52).

In a next step, a pressing process is applied to the belt shaped member100C so that a pair of the contactors47A and47B is bent. The contactors47A and47B are bent where base parts47bare inclined at designated angles relative to the surface of the belt shaped member100C. In addition, the contactors47A and47B are bent downward so that a curving part of the head end parts47aare top parts. Furthermore, the pair of the contactors47A and47B is arranged in the up and down directions in a line. The head end part47aof the contactor47A extends upward, namely in the Z1 direction. The head end part47aof the contactor47B extends downward, namely in the Z2 direction.

Processing positions of the contactors47A and47B are formed so as to be in the area D where the overlapped large diameter curved part42and the small diameter curved part44face each other.

In a next step, as shown inFIG. 17AandFIG. 17B, the belt shaped member100C is curved in a spiral manner. A process for curving in this example is the same as that in the first embodiment of the present invention and therefore the explanation thereof is omitted.

When the process for making the spiral is completed, gaps S are formed between the head end parts47aof the connectors47A and47B and an internal circumferential surface of the large diameter curved parts42. Because of this, the large diameter curved part42and the small diameter curved part44do not come in contact with each other. This gap S remains even where the contact member405is inserted in the piercing hole56of the socket50.

FIG. 18is an expanded view of a second modified example of the third embodiment of the present invention.

Referring toFIG. 18, in the contact member407of the second modified example of the second embodiment, the contactor47A (third contact part) projects from the external circumferential surface of the small diameter curved part44. The contactor47B (third contact part) projects on an internal circumferential surface of the large diameter curved part42facing the external circumferential surface of the small diameter curved part44.

The contactors47A and47B have plate spring shaped configurations. The head end part47aof the contactor47A inclines outside the external circumference of the small diameter curved part44. The contactor47B inclines inside the internal circumferential surface of the large diameter curved part42.

Although one of the contactors47is provided at each of the small diameter curved part44and the large diameter curved part42in this example, the present invention is not limited to this. For example, the contactors47A and47B may be provided in parallel or plural contactors47may be provided in a horizontal direction (where their longitudinal direction is a circumferential direction).

The contactors47A and47B are provided in a symmetrical manner in the up and down directions. In addition, the head end parts47aof the contactors47A and47B are bent and bent parts are close to the internal circumferential surface of the large diameter curved part42.

Because of this, even if dimensional unevenness is generated in a gap S between the large diameter curved part42and the small diameter curved part44, one of the contactors47can securely come in contact with the internal circumferential surface of the large diameter curved part42.

The contactors47A and47B generate a pressing force in a direction where the large diameter curved part42and the small diameter curved part44are separated from each other. As a result of this, the contact pressure between the large diameter curved part42and the small diameter curved part44can be secured by the contactors47A and47B.

The contact member407is securely shortened by the contactors47A and47B being along a line connecting in the up and down directions the second contact part43of the large diameter curved part42to the first contact part45of the small diameter curved part44.

Because of this, the mounted plural first pads22and the corresponding second pads72are electrically connected to each other with shortest lengths. Here, the first pads22of the IC chip30come in contact with the first contact part45formed at the upper ends of the contact members406. The second pads72on the printed wiring board70come in contact with the second contact parts43formed at the lower ends of the contact members407. Because of this, in the contact members407, inductance at the time of mounting can be made small so that electrical loss can be reduced.

Here, a manufacturing method of the above-mentioned contact member407is discussed with reference toFIG. 19AthroughFIG. 20B.

FIG. 19Ais a front view showing a belt shaped member100D where a contact member407is expanded.FIG. 19Bis a side view of the belt shaped member100D.FIG. 20Ais a perspective view of the curved contact member407.FIG. 20Bis a plan view of the curved contact member407.

As shown inFIG. 19AandFIG. 19B, first, metal plate working is applied to a plate made of a metal material having conductivity and spring properties, such as phosphor bronze or stainless steel. Alternatively, a belt shaped metal material wound in a roll is cut into parts having designated lengths. As a result of this, the belt shaped member100D is formed.

The height H and width B of the belt shaped member100D are determined based on the diameter of the piercing hole56or the depth of the piercing hole56(namely, thickness of the base plate52).

In a next step, a pressing process is applied to the belt shaped member100D so that a pair of the contactors47A and47B is bent. The contactors47A and47B are bent where base parts47bare inclined at designated angles relative to the surface of the belt shaped member100D. In addition, the contactor47A is bent upward and the contactor47B is bent downward. The head end part47aof the contactor47A extends upward, namely in the Z1 direction. The head end part47aof the contactor47B extends downward, namely in the Z2 direction.

Processing positions of the contactors47A and47B are formed so as to be in the area D where the overlapped large diameter curved part42and the small diameter curved part44face each other.

In a next step, as shown inFIG. 17AandFIG. 17B, the belt shaped member100C is curved in a spiral manner. A process for curving in this example is the same as that in the first embodiment of the present invention and therefore the explanation thereof is omitted.

When the process for making the spiral is completed, gaps S are formed between the head end parts47aof the connectors47A and47B and an internal circumferential surface of the large diameter curved parts42. Because of this, the large diameter curved part42and the small diameter curved part44do not come in contact with each other. This gap S remains even where the contact member405is inserted in the piercing hole56of the socket50.

FIG. 21is an expanded view of a third modified example of the third embodiment of the present invention.

Referring toFIG. 21, in a contact member408of the third modified example of the second embodiment, a contactor (third contact part)48projects from the external circumference of the small diameter curved part44. This contactor48has a plate spring configuration. The head end part48aof the contactor48is inclined to the outside of the external circumference of the small diameter curved part44.

In addition, a pair of contact pieces48band48cextending in parallel are provided at the head end part48a. The contact pieces48band48care divided by a center groove48dof the head end part48aand can generate the spring force to the large diameter curved part42.

The contact member408is securely shortened by the contactor48being along a line connecting in the up and down directions the second contact part43of the large diameter curved part42to the first contact part45of the small diameter curved part44.

Because of this, the mounted plural first pads22and the corresponding second pads72are electrically connected to each other with shortest lengths. Here, the first pads22of the IC chip30come in contact with the first contact part45formed at the upper end of the contact member408. The second pads72on the printed wiring board70come in contact with the second contact parts43formed at the lower end of the contact member408. Because of this, in the contact member408, inductance at the time of mounting can be made small so that electrical loss can be reduced.

Although a pair of the contact pieces48band48cis provided in this example, the present invention is not limited to this. For example, the contact pieces may be provided in parallel or plural contactors48and the pair of the contact pieces48band48cmay be provided in a horizontal direction (where its longitudinal direction is a circumferential direction).

Here, a manufacturing method of the above-mentioned contact member408is discussed with reference toFIG. 22AthroughFIG. 22B.

FIG. 22Ais a front view showing a belt shaped member100E where the contact member408is expanded.FIG. 22Bis a side view of the belt shaped member100E.FIG. 23Ais a perspective view of the curved contact member408.FIG. 23Bis a plan view of the curved contact member408.

As shown inFIG. 22AandFIG. 22B, first, a punching process is applied to a plate made of a metal material having conductivity and spring properties, such as phosphor bronze or stainless steel. Alternatively, a belt shaped metal material wound in a roll is cut into parts having designated lengths. As a result of this, the belt shaped member100E is formed.

The height H and width B of the belt shaped member100E are determined based on the diameter of the piercing hole56or the depth of the piercing hole56(namely, thickness of the base plate52).

In a next step, a pressing process is applied to the belt shaped member100E so that a pair of the contactors48is bent. The contactors48are bent where base parts48eare inclined at designated angles relative to the surface of the belt shaped member100E. In addition, the contactors48are bent downward so that curving parts of the head end parts48aare top parts. Furthermore, in this example, the head end part48aof the contactor48extends upward, namely in the Z1direction.

In addition, a center groove48dextending in the longitudinal direction (up and down direction) is formed at the head end part48aof the contactor48. The center groove48dmay be formed by pressing or a process after pressing applied.

Processing positions of the contactors48are formed so as to be in the area D where the overlapped large diameter curved part42and the small diameter curved part44face each other.

In a next step, as shown inFIG. 23AandFIG. 23B, the belt shaped member100E is curved in a spiral manner. A process for curving in this example is the same as that in the first embodiment of the present invention and therefore the explanation thereof is omitted.

When the process for making the spiral is completed, gaps S are formed between the connector pieces48band48cof the contactors48and an internal circumferential surface of the large diameter curved parts42. Because of this, the large diameter curved part42and the small diameter curved part44do not come in contact with each other. This gap S remains even where the contact member405is inserted in the piercing hole56of the socket50.

Although the invention has been described with respect to specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teachings herein set forth.

For example, in the above-discussed examples, although the contact member40used for the socket50for mounting the IC package10on the printed wiring board70is discussed, the present invention is not limited to this. The present invention can include other devices where two connected members having electrode pads are electrically connected to each other.

This patent application is based on Japanese Priority Patent Application No. 2007-338000 filed on Dec. 27, 2007, the entire contents of which are hereby incorporated herein by reference.