JP2909068B1 - Contact structure between spherical bump and contact - Google Patents

Abstract

An object of the present invention is to form an edge necessary for contact with a miniaturized contact piece in a sound and easy manner when a contact piece of a contact is pressed against a side surface of a spherical bump of a BGA type IC package. Ensures reliability of contact with spherical bumps. In a contact structure of a spherical bump (2) and a contact (3) in which a contact piece provided on a contact (3) is brought into pressure contact with the surface of a spherical bump (2), a base material is formed on the inner surface of the contact piece (4) by forging pressure. A concave portion 5 having a bottom is provided, and an edge portion 6 formed on an opening edge of the concave portion 5 is provided for pressure contact with the spherical bump 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact structure between a spherical bump and a contact forming an external contact of an electronic component represented by a BGA type IC package.

[0002]

2. Description of the Related Art Japanese Patent No. 2620526 discloses a contact structure between a spherical bump and a contact. The contact structure has a pair of contact pieces which are in pressure contact with opposing side surfaces of the spherical bump. A projection is formed on the contact portion of the contact piece, and the projection is made to bite into the surface of the spherical bump.

[0003]

With the recent miniaturization of the pitch of the spherical bumps, the contacts which are brought into pressure contact with the spherical bumps are becoming increasingly thinner and finer. It is technically very difficult to process projections of the required height on the surface of the contact piece in a sound manner.

[0004] In addition, when a single projection is provided on one contact piece, there is a problem that the reliability of the contact is reduced due to the miniaturization of the projection because the projection always has a single point contact with the spherical surface. In order to improve the reliability of this contact, it is difficult to employ a plurality of the protrusions in parallel in view of the current situation.

[0005]

SUMMARY OF THE INVENTION The present invention provides a contact structure between a contact and a spherical bump which solves these problems. As a means, when a single or a pair of contact pieces that the contact has on the outer surface of the spherical bump are brought into pressure contact, a bottomed bottom formed by compressing a base material by forging pressure on the inner surface of the contact piece. A recess is provided, and an edge formed at an opening edge of the recess is provided for pressure contact with the spherical bump.

[0006] As an example, while the first and second contact pieces provided with the contacts on the opposing side surfaces of the spherical bump have a contact structure in which the first and second contact pieces are brought into pressure contact with each other, the inner surfaces of the first and second contact pieces are formed by forging pressure on the inner surface. The bottomed recesses formed by compressing the material are respectively provided, and the edge portions formed at the opening edges of the recesses are subjected to pressure contact with the spherical bumps. Preferably, the recess extends horizontally in the latitudinal direction of the spherical bump. In other words, the recess is formed by an elongated bottomed groove extending substantially parallel to the lateral diameter line of the spherical bump.

The recess is groove-shaped with a closed end. Alternatively, the concave portion is circular and the edge portion is annular. The groove-shaped recess has two edges extending in parallel in the longitudinal direction, and the two edges come into pressure contact with the surface of the spherical bump at two points in the extending direction.

[0008] As a preferred example, the above-mentioned recess is formed as a bottomed groove which can be extended horizontally as described above, and a pair of upper and lower horizontally long edges are formed. The effect of ensuring accurate two-point contact can be exerted in the middle of the extending length of the groove-shaped recess, that is, in the middle of a pair of upper and lower horizontally long edges.

The circular or elliptical recess, on the other hand, has an annular edge and presses against the outer surface of the spherical bump at two points by an edge 180 ° opposite the annular edge. The annular edge portion can form an annular contact state according to the diameter of the spherical bump or the amount of biting into the bump surface.

According to the above-mentioned contact structure, it is possible to make a multi-point contact or an annular contact by the above-mentioned edge portion in one concave portion, and the contact reliability is remarkably improved.

Further, unlike the punched hole or the like, the recess is formed by compressing the contact piece in the direction of reducing the thickness of the base material of the contact piece by forging pressure, so that the strength of the fine contact piece does not decrease. Rather, work hardening can be expected in the recessed portion due to forging pressure, and thereby the base material strength of the contact portion can be improved. In addition, the above-mentioned recess having a minute size and depth can be easily formed by punching even a fine and thin contact piece, and the problem in the processing technique in the above-mentioned prior example can be effectively solved.

[0012]

DETAILED DESCRIPTION OF THE INVENTION As shown in FIGS.
The GA type IC package has a large number of spherical bumps 2 on the lower surface of the IC package body 1. The spherical bump 2 has a hemispherical shape as shown in FIG. 1A or a substantially spherical shape as shown in FIG. 1B, and is formed of a low melting point metal such as a solder material. The BGA type IC package is mounted on the wiring board by fusing to the wiring pattern on the wiring board.

Therefore, in such a test socket of a BGA type IC package, a contact structure in which the contact of the test socket and the pressure contact of the spherical bump can be performed without damaging the bottom dead center of the spherical bump. It is desired that

For this reason, in the first, second, and third embodiments described below, a single or a pair of contact pieces 4 provided on the outer surface of the spherical bump 2 by the contact 3 are press-contacted. In the contact structure to be formed, a recess 5 formed by compressing the base material by applying forging pressure to the inner surface of a single or a pair of contact pieces 4 is provided, and an edge portion 6 formed at an opening edge of the recess 5 is provided.
Is provided for pressure contact with the spherical bump 2.

As shown in FIGS. 4A and 4B and FIGS. 5A and 5B, the edge 6 of the recess 5 is brought into pressure contact with the periphery of the bottom dead center Z of the spherical bump 2 so that the bottom dead center Z is recessed. In this case, the spherical bump 2 has a structure in which the bottom dead center Z is prevented from being damaged.

The first, second and third embodiments described below are distinguished by the contact position of the recess 5 with the spherical bump 2.

The first and second embodiments (FIGS. 6A, B1, B
(See all drawings except 2) The inner surfaces of the first and second contact pieces 4 are formed in a contact structure in which the first and second contact pieces 4 provided on the contact 3 on the opposing side surfaces of the spherical bump 2 are brought into pressure contact. Each of the recesses 5 is formed by compressing the base material by applying forging pressure thereto. An edge portion 6 formed at the opening edge of each recess 5 is configured to be brought into pressure contact with the spherical bump 2. In the first embodiment, as shown in FIGS.
The edge 6 of the recess 5 of the second contact piece 4 is
Of the lower hemisphere.

As a specific example, the distal ends (free ends) of the first and second contact pieces 4 are bent at a constant opening angle so as to face the left and right side surfaces of the lower hemisphere of the spherical bump 2. Then, the recess 5 is formed on the inner surface of the bent piece 8.

As a preferred example, a curved surface 9 which bends the free end of each contact piece 4 into a curved shape and bulges inward on its inner surface.
Is formed, and the recess 5 is formed substantially symmetrically in the middle of the curved surface 9.

The spherical bump 2 is connected to the first and second contact pieces 4.
Of the lower hemisphere and the left and right side surfaces of the lower hemisphere, while being placed on the curved surface 9, contact the edge portion 6 of the concave portion 5 formed on the curved surface 9 of the first and second contact pieces 4. Or in annular contact.

The recesses 5 are shown in FIGS. 3, 4B, 5B, 7
As shown in A, it is grooved with a closed end. Or FIG.
B, FIG. 5B, and FIG. 7B, the recess 5 is made circular or elliptical to make the edge portion annular. In the case of the above-mentioned groove-shaped recess 5a, it comes into pressure contact with the outer surface (left and right side surfaces) of the spherical bump 2 in the middle of the two edge portions 6 extending in parallel with the longitudinal direction.

In the case of the circular recess 5b, the annular edge portion 6 is formed on the outer surface (left and right side surfaces) of the spherical bump 2.
To make pressure contact in a ring.

In the case of the groove-shaped recess 5a, as shown in FIG. 7A, the two edges 6 of one recess 5a
When a two-point contact structure is formed at the points P1 and P2, and in the case of a circular or oval recess 5b, the contact structure is formed at the points P1 and P2 by the annular edge portion 6 as shown in FIG. An annular contact structure can be formed.

On the other hand, in the second embodiment, FIG.
As shown in FIG. 3B, the distal end portions of the first and second contact pieces 4 of the contact 3 are disposed so as to face each other near a weft passing through both ends of the lateral diameter line R1 of the spherical bump 2. In other words, the lateral diameter line R1 Are disposed facing the left and right side surfaces of the spherical bump 2 near both ends of the
The recess 5 is forged on the inner surface of each of the tip portions.
Are brought into pressure contact with the left and right side surfaces of the spherical bump 2.

In the case of the groove-shaped recess 5a, a two-point contact structure is formed by the two edges 6 of one recess 5a.
In the case of the circular recess 5b, the annular edge portion 6 can form an annular contact structure.

Preferably, as shown in FIGS. 4A and 5A,
In any of the first and second embodiments, and in the third embodiment described below, the concave portion 5 has a diameter line R of the spherical bump 2 crossing the opening surface 10 at a substantially right angle. They are arranged with an orientation angle. In this case, in FIG. 5A showing the second embodiment, the horizontal diameter line R1 is the opening surface 1
Intersects the center of zero at right angles.

As shown in FIG. 7C, using each embodiment,
When performing the burn-in test on the AG type package, the spherical bumps 2 are softened, and the edge portions 6 are formed in the first and second portions.
Biting into the surface of the bump 2 by the elasticity of the contact piece 4,
At the same time, part of the bump 2 enters the recess 5. Therefore, highly reliable contact by the first and second contact pieces 4 is ensured.

The contact 3 can be provided with only one of the first and second contact pieces 4 and can be in one-side contact. Also in this case, one recess 5 formed in a single contact piece
Thereby, the two-point contact or the annular contact can be secured.

That is, when the contact 3 having the first and second contact pieces 4 is used as shown in FIG.
A four-point contact structure or a pair of annular contact structures can be formed on the left and right side surfaces of the.

The above-mentioned groove-shaped recess 5a is located in the horizontal direction,
In a direction that is substantially parallel to the horizontal diameter line R1. Alternatively, as shown in FIGS. 4A and 5A, the groove-shaped recess 5 can extend in the vertical direction (up and down direction). In this case,
The bump 2 extends substantially in parallel with the vertical diameter line R2, or extends in a vertical direction at a certain inclination angle.

The lateral groove-shaped recesses 5a of the first and second embodiments are arranged so that each edge portion 6 comes into pressure contact with one common latitude line of the spherical bump 2 vertically and substantially symmetrically. Can be.

FIG. 6A, FIG. 6B1, FIG.
(See B2) In the third embodiment, a single recess 5 formed in a single contact piece 4 provides pressure contact with the spherical bump 2. The contact piece 4 is formed by bending a seat 7 at its tip so as to face a spherical surface including the bottom dead center Z of the spherical bump 2, and the base material is compressed on the upper surface of the seat 7 by forging. It has a recess 5 with a bottom formed. As in the first and second embodiments, the recesses 5 are groove-shaped (FIG. 6B1) or circular or elliptical (FIG. 6B2). There is a dead center Z.

The contact piece 4 has an upward parallel edge portion 6 or an annular edge portion 6 formed at the opening edge of the forged recess 5, and the circular or elliptical edge portion 6 has the spherical bump 2. Contact around the bottom dead center Z
Or contact in a ring. A pair of parallel edge portions 6 of the groove-shaped recess form a two-point contact structure around the bottom dead center Z of the spherical bump 2.

In the third embodiment, the spherical bump 2 is pressed against the edge 6 by pushing down the IC package body 1 downward. Therefore, the edge portion 6 bites into the surface of the spherical bump 2 and makes active contact. The advantage of the third embodiment is that it can effectively cope with the minute pitch of the spherical bumps 2, and even if the contacts 3 are miniaturized, the recesses 5 can be easily formed by forging, and the two-point contact or the annular contact Is to be able to secure.

FIGS. 8A and 8B show examples of forging of the recess 5 which can be employed in the first to third embodiments.
As shown in FIG. 8A, the contact piece 4 is placed on the lower mold 10, and the outer surface of the tip of the contact piece 4 is supported on the surface of the lower mold 10. Then, as shown in FIG. 8B, the upper die 11 having the pressing punch 12 is lowered, and the pressing punch 12 is driven into the inner surface of the distal end portion of the contact piece 4.

That is, the base material of the contact piece 4 is compressed by the punch 12 to form the recess 5 having the bottom. Needless to say, the punch 12 has a shape corresponding to the desired shape of the recess 5. Each of the processes using the punch 12 is a cold forging process, and the surface portion of the recess 5 is work hardened by this process, whereby the strength can be improved and the contact effect can be improved.

As shown in FIGS. 2A and 2B, the contact 3 shown in the first, second, and third embodiments is an elongated elastic strip 14 extending upward from the planting portion 13 in the socket body.
The first and second contact pieces 4 are stamped and bent integrally with the tip of the elastic strip 14. Therefore, the contact piece 4 has elasticity by itself and can be elastically displaced downward or laterally by the elastic strip 14.

The male terminal 15 is integrally punched downward from the planted portion 13 and is used for connection to a printed circuit board.

[0039]

According to the above-described contact structure, it is possible to make a multipoint contact or an annular contact by the edge portion in one recess, and the contact reliability is remarkably improved. Also, unlike the punched hole, the recess is formed by compression (plastic deformation) in the direction of reducing the thickness of the base material of the contact piece by forging pressure, so that the strength of the fine contact piece does not decrease. Rather, work hardening can be expected in the recessed portion due to forging pressure, and strength can be improved.

In addition, the above-mentioned recess having a required size and depth can be easily formed by punching even a fine and thin contact piece, and the problem of the processing technique in the preceding example can be effectively solved.

[Brief description of the drawings]

1A and 1B are side views showing examples of the shape of a spherical bump of a BGA type IC package, and FIG. 1C is a bottom view thereof.

FIG. 2A is a front view of a contact showing an embodiment of the present invention, and FIG.

FIG. 3 is a perspective view of a contact showing a first embodiment relating to a contact structure between a concave portion and a spherical bump of the present invention.

FIG. 4A is a cross-sectional view showing a contact structure between the recess and the spherical bump, and FIG. 4B is a rear view of the same.

FIGS. 5A and 5B show a second embodiment of a contact structure between a recess and a spherical bump according to the present invention, wherein A is a cross-sectional view thereof, and B is a sectional view.
Is a rear view.

FIGS. 6A and 6B show a third embodiment of the contact structure between the recess and the spherical bump of the present invention, wherein A is a cross-sectional view of the contact viewed from the side, and B1 and B2 are grooves formed in the recess. FIG. 4 is a cross-sectional view of an example in which a circle is formed and an example in which a circle is formed in a front view.

FIG. 7A shows an example in which a groove-shaped recess contacts a spherical bump, and FIG.
Is a side view for explaining an example in which a circular recess comes into contact with the bump, and C is an enlarged sectional view showing a structure in which the bump bites into and contacts the recess.

FIGS. 8A and 8B are cross-sectional views showing examples of cold forging of a recess in the first, second, and third embodiments.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 IC package main body 2 Spherical bump 3 Contact 4 Contact piece 5 Concave part 5a Groove type concave part 5b Circular concave part 6 Edge part 7 Seat piece 8 Folding piece 9 Curved surface 10 Opening surface P1, P2 Contact point R Diameter line R1 Horizontal diameter line R2 Vertical diameter line Z Bottom dead center

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-10-144440 (JP, A) JP-A-10-74571 (JP, A) JP-A 8-78123 (JP, A) JP-A 7-78 287048 (JP, A) JP-A-6-203926 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01R 33/76 H01L 23/32 H01R 13/11

Claims (5)

(57) [Claims] In a contact structure of a spherical bump and a contact in which a contact piece which a contact has on a surface of a spherical bump is brought into pressure contact, a bottomed material formed by compressing a base material by forging pressure on an inner surface of the contact piece. A contact structure between a spherical bump and a contact, wherein the concave portion is provided, and an edge portion formed at an opening edge of the concave portion is provided for pressure contact with the spherical bump. 2. A contact structure of a spherical bump and a contact in which a first and a second contact piece provided on a side surface of the spherical bump, which the contact has, is brought into pressure contact with an inner surface of the first and the second contact piece. Each of the bottomed recesses formed by compressing the base material by forging pressure is provided, and the edge formed at the opening edge of each recess is provided for pressure contact with the spherical bump. Characteristic contact structure between spherical bumps and contacts. 3. The contact structure between a spherical bump and a contact according to claim 1, wherein the concave portion is extended horizontally in a direction parallel to the latitude of the spherical bump. 4. A contact structure between a spherical bump and a contact according to claim 1, wherein said recess is a groove having a closed end. 5. A contact structure between a spherical bump and a contact according to claim 1, wherein said concave portion is circular and said edge portion is annular.