JP3128540B2 - Contact structure of contact to spherical bump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact structure of a contact with a spherical bump forming an external contact of a BGA type IC package or the like.

[0002]

2. Description of the Related Art Japanese Patent No. 2620525 (Japanese Unexamined Patent Application Publication No.
No. -78123) shows a contact structure of a contact with a spherical bump, and this contact structure has a pair of contact pieces which are in pressure contact with opposing side surfaces of the spherical bump, and a contact portion of both contact pieces. A protrusion is formed on the surface of the spherical bump.

[0003]

The prior art described above employs a contact structure in which projections are cut into both sides of a spherical bump.
This has the advantage of greatly improving the reliability of the contact and not damaging the bottom dead center of the spherical bump mounted on the surface.

[0004] The present invention, while enjoying the advantages of the preceding example,
A spherical bump that provides a function that allows the projection of the first contact piece and the projection of the second contact piece to make stable and sound pressure contact with one side and the other side of the spherical bump, thereby ensuring highly reliable contact. A contact structure is provided.

[0005]

According to the present invention, as a means for solving the above-mentioned problems, the first contact piece is brought into pressure contact with one side surface of the bump on a meridian passing through one end of a diameter line of the spherical bump. One projection is provided, and the second contact piece is separated from the second and third projections which are in pressure contact with the other side surface of the spherical bump on both sides of the meridian passing through the other end of the diameter line of the spherical bump. Placed.

With the above-mentioned contact structures, the spherical bump and the contact make three-point contact on opposing side surfaces of the spherical bump, thereby securing a relative position of each projection with respect to the spherical bump, thereby providing a stable and sound load. Pressure contact can be secured.

The first, second, and third protrusions are formed by protrusions extending in the vertical direction of the spherical bumps. The protrusions are formed on both the large-diameter spherical bump and the small-diameter spherical bump. A proper contact can be obtained on the extension line of.

The second contact piece is provided with a projection which is spaced apart. Preferably, the projection which is spaced apart is formed by a ridge extending vertically as described above. The ridge has an inclination angle that can be expanded downward,
Both sides of the spherical bumps having different diameters can be brought into contact with an appropriate pressure at an appropriate position corresponding to the diameter.

A pressure receiving surface is formed between the second and third projections of the second contact piece to set the amount of the first and second projections biting into the spherical bump.

[0010] Alternatively, an escape groove for allowing the spherical surface of the spherical bump to escape is formed between the second and third projections of the second contact piece.

[0011] The pressure receiving surface or the relief groove uniformly sets the maximum bite amount of both projections spaced apart on both sides of the pressure receiving surface and the relief groove.

[0012] Further, the three-point contact by the projections can significantly improve the reliability of the contact by the first and second contact pieces.

[0013]

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. Is often fused to the wiring pattern on the wiring board, and the BGA type IC package is directly mounted on the wiring board without using a socket.

Therefore, in the test socket of such 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, the basic structure of the present invention is to make a pair of contact pieces come into pressure contact with the opposite left and right side surfaces of the spherical bump as in the above-mentioned prior art. Then, a three-point contact structure with at least a projection is formed on both opposing side surfaces of the spherical bump. 2 to 7 below
The embodiment will be described in detail with reference to FIG.

A large number of spherical bumps 2 are provided on the lower surface of the BGA type IC package body 1.
The first and second contact pieces 4 and 5 having elasticity provided by the contact 3 are brought into pressure contact with the opposing side surfaces of the contact 3.

As shown in FIG. 4 and the like, the first contact piece 4 has a first projection 6 which comes into pressure contact with one side surface of a spherical bump 2 on a meridian A1 passing through one end of a lateral diameter line R1 of the bump. The second contact pieces 5 are spaced apart from each other by a second protrusion 7 that is in pressure contact with the other side surface of the spherical bump 2 on both sides of a meridian line A2 passing through the other end of the diameter line R1. And the third protrusion 8. Here, the meridian is a line connecting the bottom dead center P of the spherical bump 2 and the virtual top dead center and corresponding to a meridian on the earth.

As shown in FIGS. 2, 3 and the like, the first contact piece 4 and the second contact piece 5 of the contact 3 extend vertically and are disposed to face left and right. , The second contact pieces 4 and 5 have male terminals 10 connected to each other and connected to a printed circuit board extending downward from the connecting portion 9. The first and second contact pieces 4 and 5 and the male terminal 10 are integrally formed by punching from a metal plate.

The first and second contact pieces 4 and 5 have opening and closing elasticity, can be expanded outwardly against the elasticity, and can be restored to the inner side according to the elasticity. By this restoring force, the protrusions 6, 7, 8 are brought into pressure contact with the left and right side surfaces of the spherical bump 2. The first and second contact pieces 4 and 5 are extended upward from the lower end connecting portion 9 so as to face upward, and the inner surfaces of the upper ends (free ends), that is, the first and second contact pieces 4 and 5 are formed. The protrusions 6, 7, 8 are formed on the inner surface of the free end.

Preferably, the projections 6, 7, 8 are formed by protrusions extending in the vertical direction of the spherical bump 2. The ridges forming the first, second, and third projections 6, 7, 8 extend from the upper end edge of the first contact piece 4 to the lower end connecting portion 9 of the first and second contact pieces 4, 5. I do.

As shown in FIGS. 5A and 5B,
The ridges 7 and 8 make pressure contact with the left and right side surfaces of the spherical bump 2 in the middle of the extending direction.
The small-diameter spherical bump 2a shown in FIG. 5A and the large-diameter spherical bump 2b shown in FIG. 5B have different pressure contact positions.

More specifically, the ridges forming the protrusions 6, 7, 8 of the first and second contact pieces 4, 5 are provided at the tip of the ridge with respect to the small-diameter spherical bump 2a shown in FIG. 5A. Same bump 2 on the side
5B, and comes into contact with the large-diameter spherical bump 2b shown in FIG. 5B at a lower level than the small-diameter spherical bump 2b. Appropriate pressure contact can be expected for any of the shaped bumps 2b.

As the most ideal example, the first contact piece 4
Of the spherical bump 2 is brought into pressure contact with a meridian A1 passing through one end of the lateral diameter line R1 of the spherical bump 2, and the projections 7, 8 of the second contact piece 5 are formed by a meridian A2 passing through the other end of the lateral diameter line R1. Are arranged substantially symmetrically on both sides of the substrate and brought into pressure contact with the spherical bump 2.

That is, the first projection 6 and the second and third projections 7 and 8 are arranged at positions forming respective vertices of an isosceles triangle when viewed in a plan view, and are added on substantially the same latitude B of the spherical bump 2. Arrange to make pressure contact. Here, latitude line B is meridian A
It is a line corresponding to the latitude line on the earth that intersects 1 and A2.

The first protrusions 6, that is, ridges as an example, are arranged on a substantially center line of the first contact piece 4 in the vertical direction.
The third protrusions 7 and 8, that is, the ridges as an example thereof, are arranged side by side substantially symmetrically with respect to the vertical center line of the second contact piece 5.

The first contact piece 4 has pressure receiving surfaces 16 on both sides of the projection as the central projection 6 for setting the amount of biting of the projection 6 into the spherical bump 2.

Similarly, the second contact piece 5 forms a pressure receiving surface 17 between the projections 7 and 8 arranged apart from each other, that is, between a pair of protrusions. When the spherical bump 2 is softened by the burn-in test, the projections 6, 7, and 8 become the first and second contact pieces 4,
The elasticity of 5 causes the surface of the spherical bump 2 to bite. At this time, the pressure receiving surfaces 16 and 17 receive the spherical surface of the spherical bump 2 and serve as means for setting the maximum bite amount of the projections 6, 7 and 8.

The projections 6, 7, 8 may be point projections,
It is formed by the above-mentioned ridge, and as an example, in any case, it is arranged so as to be in pressure contact on the same latitude line B of the spherical bump 2.

As shown in FIG. 6, a pair of ridges as projections 7 and 8 formed on the second contact piece 5 extend in the up-down direction and are arranged side by side at substantially equal intervals in the left-right direction. Alternatively, as shown in FIG. 7, the two ridges forming the second and third projections 7 and 8 of the second contact piece 5 extend at an inclination angle that can be expanded downward.

By providing the projections forming the second and third projections 7 and 8 at the above-mentioned inclination angles, the small-diameter spherical bump 2a and the large-diameter spherical bump 2a are provided as shown in FIGS. The contact positions of the two ridges on the spherical bump 2b are automatically changed.

That is, as shown in FIG. 7C, the two ridges contact the small-diameter spherical bump 2a at the contact points P1 and P2, and the interval t1 between the two contact points P1 and P2 is small. Yes,
On the other hand, the large-diameter spherical bumps 2b of the two ridges make contact at the contact points P3 and P4, and the interval t2 between the two contact points P3 and P4 becomes large.

As shown in FIGS. 7A1 and A2, the pressure contact force of the projections 6, 7, 8 by the first and second contact pieces 4, 5 is small for the small-diameter spherical bump 2a. 2 contact pieces 5
Even when the two projections 7 and 8 are close to each other, damage to the local portion of the spherical bump 2 is small.

On the other hand, as shown in FIGS. 7B1 and B2, the pressing contact forces of the projections 6, 7, 8 of the first and second contact pieces 4, 5 are additive to the large-diameter spherical bump 2b. Will be great. Therefore, if the two projections 7, 8 of the second contact piece 5, that is, the two ridges are brought into pressure contact with the large-diameter spherical bump 2b at the same interval as the small-diameter spherical bump 2a, damage to the local bump portion becomes excessive. This causes excessive deformation of the spherical bumps and hinders surface mounting.

This problem can be effectively solved by gradually increasing the distance between the two projections 7, 8 of the second contact piece 5, that is, the distance between the two ridges, as described above. That is, the damage of the large-diameter spherical bump 2b to a local part can be reduced by increasing the contact interval between the projections 7 and 8 to the large-diameter spherical bump 2b as compared with the small-diameter spherical bump 2a. it can.

[0035]

According to the above-mentioned contact structure, the spherical bump and the contact come into three-point contact on the opposing side surfaces of the spherical bump, whereby the relative positions of the respective projections with respect to the spherical bump are ensured to be stable and sound. Pressure contact can be ensured.

The first, second, and third protrusions are formed by protrusions extending in the vertical direction of the spherical bump, so that the large-diameter spherical bump and the small-diameter spherical bump can be formed. Proper contact is obtained on the extension line of the ridge.

In addition, the second and third projections are formed by the ridges extending in the vertical direction as described above, and the two ridges are provided with an inclination angle capable of expanding downward. Can be brought into contact with both sides of different spherical bumps at appropriate positions according to their diameters with appropriate pressing force.

Further, the three-point contact by the projection can significantly improve the reliability of the contact by the first and second contact pieces.

[Brief description of the drawings]

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

FIG. 2 is a perspective view of a main part of a contact showing an example of a three-point contact structure of the present invention.

FIG. 3 is a plan view of the contact.

FIG. 4 is a cross-sectional view showing a state in which the contact is pressed against a spherical bump.

FIG. 5A is a side view showing a state in which a contact is pressed against a small-diameter spherical bump; FIG. 5B is a side view showing a state in which the contact is pressed against a large-diameter spherical bump;

FIG. 6 is a rear view showing a contact state of the contact.

FIG. 7 is a cross-sectional view showing a state where a contact is pressed against a small-diameter spherical bump, A2 is a front view thereof, and B1 is
FIG. 3 is a cross-sectional view showing a state in which a contact is pressed against a large-diameter spherical bump, B2 is a front view of the same, and C is a plan view illustrating contact points of the contact with a small-diameter and large-diameter spherical bump.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 BGA type IC package main body 2 Spherical bump 3 Contact 4 First contact piece 5 Second contact piece 6 First protrusion 7 Second protrusion 8 Third protrusion 16, 17 Pressure receiving surfaces P1 to P3 Contact point R1 Horizontal diameter line A1, A2 Meridian B Latitude

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H01L 21/66 H01L 21/66 F 23/12 23/12 L (56) References JP-A-10-111314 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 1/06-1/067 G01R 31/26 H01L 21/60

Claims (3)

(57) [Claims] 1. A contact structure of a contact with a spherical bump in which a first contact piece and a second contact piece, which are provided on a side face of a spherical bump, are brought into pressure contact with each other, wherein the first contact piece has a diameter of the spherical bump. A first protrusion which is in pressure contact with one side of the bump on a meridian passing through one end of the wire, wherein the second contact piece is provided on both sides of a meridian passing through the other end of the diameter line of the spherical bump; A contact structure for contacting the spherical bump, the second and third protrusions being spaced apart from each other and being in pressure contact with the other side surface. 2. The contact of a contact with a spherical bump according to claim 1, wherein said first, second, and third projections are formed by protrusions extending in a vertical direction of the spherical bump. Construction. 3. The contact structure of a contact with a spherical bump according to claim 2, wherein both of the ridges forming the second and third projections have an inclination angle which can be expanded downward.