JPH11297440A - Ic socket and operation method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly flatten the heights of solder bumps deformed at contact time of a test and burn-in by constituting a vertically movable guide plate, having the same-shaped hole penetrated with plural divided pieces formed in the side tip part of the solder bumps of contact pins, to be horizontally supported by a guide plate column in an intermediate position by leaving the constant length on the tip. SOLUTION: Divided pieces of an arc-shaped projection are formed of, for example, two notches on the upper end of a springy plunger 3c in a cylinder 3a of plural contact pins 3 held by a pin support plate 4 in an IC socket. When the IC socket is moved upward, a guide plate 6 having a through-hole of the divided pieces is horizontally supported in an upper intermediate position, and the tip of the constant length projecting parts 7a of both side columns 7 erected on a support stand 5 abuts to the bottom surface of an IC 2, so that the contact pins 3 apply prescribed stresses to solder bumps 2a. When a test and burn-in are finished, the forefront of the downward deforming solder bumps 2a is regulated by the guide plate 6 to reduce the fluctuations in a height.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC socket having a solder bump, such as a chip scale package (CSP) type IC, and an IC socket used at the time of test and burn-in, and a method of operating the same.

[0002]

2. Description of the Related Art Recently, CSP and BGA ICs having dimensions almost similar to the outer shape of an IC chip have begun to be used for portable equipment. It is suitable for small, light and thin electronic devices, and is expected to increase in the future. When the ICs of these packages are mounted on a printed circuit board, solder bumps constituting a part of the IC are placed at predetermined positions on the printed circuit board, and are fixed by soldering by reflow. FIG. 10 is a diagram for explaining a contact portion and a contact state when an electrical test is performed by applying a contact pin of an IC socket to a bump of a CSP type IC in the prior art. Reference numeral 1 denotes one of a plurality of contact pins arranged side by side in an IC socket, and an outline of a type in which a spring 1b is inserted into a cylinder 1a called a sleep to form a springy plunger 1c. Is shown. In addition, a conical concave hole 1d is provided at the tip of the plunger 1c. Next, FIG.
FIGS. 3C and 3D are diagrams illustrating a state immediately before the contact pin 1 contacts a solder bump (solder ball) (height h) 2 a of the CSP type IC 2. FIGS. This figure shows the state of contact with the solder bump 2a and the shape of the solder bump after the contact. The solder bump 2a is deformed and its height H is different from the initial height h. Next, FIG.
FIG. 2 is a view showing the shape of a plurality of solder bumps which are contacted by contact pins arranged in a row.
Due to the variation in the spring force, the variation in the physical characteristics of the solder bumps, the variation in the temperature environment of the solder bumps, and the like, the height H varies as shown in the figure.

[0003]

By the way, in order to successfully solder the CSP type IC as described above, a plurality of solder bumps of the above-mentioned IC are required to contact the printed circuit board at the same time. There must be. That is, in order to solder a plurality of solder bumps, it is generally said that a variation in the height of the solder bumps, in other words, a requirement for flatness is required to be 50 μm or less. However, as described above, in the process of manufacturing a CSP type IC, there are a test and a burn-in process. In each of these processes, a contact pin is brought into contact with a solder bump of the IC to supply an electric signal to perform a test or a burn-in. The temperature environment in each step is generally 25 ° C. at room temperature or 80 ° C. at a high temperature in a test, and 125 ° C. in a burn-in. Therefore, when the test is performed by bringing the contact pins into contact with the solder bumps, the higher the ambient temperature of the solder bumps is as high as 125 ° C. as in the case of the burn-in, the more the scratches and dents on the solder bumps are made. Is large. The solder used for this type of solder bump is soft by nature, including so-called eutectic solder, and has the property of becoming softer at high temperatures, and is greatly damaged, dented, and deformed. That is, it is necessary to recognize that the solder bump is deformed at the time of test and burn-in contact.

As described above, the solder bump of the CSP type IC is deformed by the contact at the time of high-temperature burn-in,
Variations in the height of the solder bumps of the entire IC are out of the allowable range, so that a soldering problem occurs, and a poor contact between the IC and the printed circuit board tends to occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the height of the deformable solder bumps can be kept constant at the time of IC test and burn-in contact by ensuring a certain flatness. It is an object of the present invention to provide a socket having a function of correcting solder bumps so that a variation in height is kept within an allowable range so that good soldering with a printed circuit board can be performed.

[0006]

According to a first aspect of the present invention, there is provided an IC socket including a vertically movable contact pin having a tip end facing a solder bump formed in a plurality of divided pieces. A vertically movable guide plate provided with a hole of the same shape through which the split piece at the distal end penetrates, and a guide plate support that horizontally supports the guide plate at a predetermined length at the distal end and at an intermediate position therebetween. It is provided.

According to a second aspect of the present invention, there is provided an IC socket comprising a plurality of contact pins each including a cylinder having an elastic body therein, and a plunger inserted into the cylinder. It is supported by a common pin support plate arranged in parallel.

In the IC socket according to a third aspect of the present invention, the divided pieces of the contact pins and the through holes of the guide plate through which the contact pins penetrate are arranged symmetrically with respect to the center of the circle.

In the IC socket according to a fourth aspect of the present invention, the two divided pieces of the contact pin and the two through holes penetrating the two are symmetrically arranged so as to be opposed to each other in the vertical direction. ing.

In the IC socket according to a fifth aspect of the present invention, the divided piece of the contact pin and the through hole of the guide plate through which the contact pin passes are equally divided into three parts with respect to the center of the circle. .

In the method of operating an IC socket according to a sixth aspect of the present invention, first, the tip of the guide plate support is brought into contact with the IC so that the guide plate is brought into contact with the tips of all the solder bumps in the height direction. Thereafter, the contact pins are further protruded from the guide plate in the direction of the solder bumps so that the tips thereof are pressed against the solder bumps.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 to 7 are diagrams for explaining Embodiment 1 of the present invention. First, in FIG. 1, 2 is an IC such as a CSP, and 2a is its solder bump. Reference numeral 3 denotes a plurality of (three in the figure) contact pins arranged in an IC socket, and a spring plunger 3c is formed via a spring 3b in a cylinder 3a called a sleep. As shown in FIG. 6, the tip (upper end) of the plunger 3c has two or more divided pieces 3e symmetrical with respect to the center of the circle. That is, in the present embodiment, the cylindrical body is formed into two symmetrical divided arc-shaped projections 3e with two cuts 3d facing each other from the upper end. The length (L) of the contact pin 3 is 5 to 10 mm, and the upper end diameter of the plunger is about 0.4 mmφ. Next, reference numeral 4 denotes a part of an IC socket, a pin support plate for fixing and holding the cylindrical portions 3a of the three contact pins 3 together, 5 a support for a guide plate 6 described later, and 7 a The guide plate 6 is a two-sided support standing upright on the support base 5, and is horizontally supported at an intermediate position above the guide plate support 7, and
As shown in FIG. 7, at the same time as the positioning of the contact pin 3, the divided arc-shaped protrusion 3 at the tip of the contact pin 3 is formed.
e, two divided arc-shaped holes 6a corresponding to it to penetrate
(Through holes) are provided. The guide plate support 7
Has a protruding portion 7a projecting above the supporting portion of the guide plate 6 by a certain length in order to support the guide plate 6 and to keep the distance between the bottom surface of the IC 2 and the guide plate 6 constant.

Next, the operation will be described. FIG. 1 shows a state before the contact pins 3 contact the solder bumps 2a of the IC 2. FIG. 2 shows a state in which the inside of the dotted line of the IC socket moves upward in FIG. 7 shows a state in which the tip of 7 contacts the bottom surface of the IC 2 and the upper surface of the guide plate 6 contacts the lower surfaces of all the solder bumps (solder balls). Then, in FIG. 3, the contact pins 3 and the pin support plate 4 are further moved in the dotted frame of the IC socket, ie, the upper side in the figure, and the contact pins 3 are electrically connected to the solder bumps 2. FIG. 4 shows a state in which the solder bump is deformed by applying the necessary stress to the solder bump.
FIG. 5 shows a state in which the test or burn-in is completed, the IC socket is removed from the IC, and a deformed state of the solder bump at that time. Here, the plurality of solder bumps 2a in FIG.
In the peripheral direction and the tip of the bump, the tip of the bump hits the guide plate 6 in the downward direction. As shown in FIG. 5, a plurality of bump heights H
Are uniformly flat. As described above, the deformation of the solder bumps does not occur in the height direction due to the presence of the guide plate 6, but on the other hand, the degree of crushing is large in the peripheral direction. Since the solder bumps once melt when soldered, if the height is uniform and flat, even if the solder bumps are slightly crushed in the horizontal direction, there is no problem.

Embodiment 2 FIG. In the first embodiment, as shown in FIG.
8 are symmetrically arranged so as to be opposed to each other in the lateral direction. In the second embodiment, the divided arc-shaped holes 6b are formed as shown in FIG.
As shown in FIG. 7, the holes shown in FIG. 7 are symmetrically arranged so that they are rotated 90 ° and face each other in the vertical direction. Along with this, it goes without saying that the tip of the plunger 2 penetrating this hole is also rearranged. With the above configuration, the insulation distance (a) between the contact pins can be increased, and the size can be further reduced.

Embodiment 3 In the first and second embodiments,
In FIG. 2, the tip of the plunger 2 is described as being divided into two parts. However, as shown in FIG. 9, the divided arc-shaped hole 6c may be divided equally into three parts on the circumference. By doing so, the stress on the solder bump is dispersed, and the deformation of the solder bump at the time of contact is minimized.

[0016]

According to the first to third and sixth aspects of the present invention, a contact pin having a plurality of divided pieces at the tip is provided.
Since the guide plate having a through hole having the same shape as that of the above-mentioned divided piece is passed through and supported at a predetermined intermediate position between the both-side columns, the height of the solder bumps of the entire IC can be formed uniformly and flat. This has the effect of exerting a proper correction function of the bump.

According to the fourth aspect of the present invention, the two holes of the guide plate through which the two divided pieces of the contact pin penetrate are arranged symmetrically so as to face each other in the vertical direction. The insulation distance between the pins can be increased, and the size can be further reduced.

According to the fifth aspect of the present invention, by dividing the through hole of the guide plate into three parts, there is an effect that the deformation at the time of contact of the solder bumps is reduced as much as possible by being dispersed from the stress on the solder bumps.

[Brief description of the drawings]

FIG. 1 is a front view of an IC socket according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory view of the IC socket according to the first embodiment of the present invention;

FIG. 3 is an operation explanatory view of the IC socket according to the first embodiment of the present invention;

FIG. 4 is an operation explanatory view of the IC socket according to the first embodiment of the present invention;

FIG. 5 is a front view showing a shape of a solder bump according to the first embodiment of the present invention.

FIG. 6 is a plan view showing a tip shape of a plunger in the IC socket according to the first embodiment of the present invention.

FIG. 7 is a plan view showing a guide plate of the IC socket according to the first embodiment of the present invention.

FIG. 8 is a plan view showing a guide plate of an IC socket according to a second embodiment of the present invention.

FIG. 9 is a plan view showing a guide plate of an IC socket according to a third embodiment of the present invention.

10A is a cross-sectional view showing one contact pin of a conventional IC socket taken out, and FIGS.
(e) is an explanatory view showing a step of forming solder bumps of the IC.

[Explanation of symbols]

2 IC, 2a solder bump, 3 contact pin, 3
a cylindrical part, 3b spring, 3c plunger, 3d
Notch, 3e split piece, 4 pin support plate, 6 guide plate, 6a through hole, 7 support, 7a protrusion.

Claims (6)

[Claims] In an IC socket having solder bumps, a tip facing the solder bump has a plurality of vertically movable contact pins formed in a plurality of divided pieces, and the tip of the contact pin is divided. A vertically movable guide plate provided with a hole through which a piece passes, and this guide plate,
An IC socket comprising: a support having a fixed length at its tip and horizontally supported at an intermediate position therebetween. 2. A plurality of contact pins each comprising a cylinder having a built-in elastic body and a plunger inserted into the cylinder, and each of the cylinder portions is a common pin support plate arranged in parallel with a guide plate. 2. The IC socket according to claim 1, wherein the IC socket is supported. 3. The contact piece according to claim 1, wherein the tip split piece of the contact pin and the through hole of the guide plate through which the tip piece penetrates are symmetrically arranged with respect to the center of the circle.
Or the IC socket according to 2. 4. The method according to claim 1, wherein the two divided pieces of the contact pin and the two through holes of the guide plate through which the contact pin penetrates are respectively symmetrically arranged so as to face each other in the vertical direction. Item 3. The IC socket according to Item 3. 5. The integrated circuit according to claim 3, wherein the divided pieces of the contact pins and the through holes of the guide plate through which the contact pins penetrate are equally divided circumferentially into three parts with respect to the center of the circle. Socket. 6. The method for operating an IC socket according to claim 1, wherein the guide plate is first brought into contact with the IC in a height direction by contacting the tip of the guide plate support with the IC. And thereafter, the contact pins are further protruded from the guide plate in the direction of the solder bumps, and the tips thereof are pressed against the solder bumps.