JP2003017209A - Socket for ic package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a socket for IC package which can gain a substantial pressing power at time of burn-in and can operate with a small operating force at time of mounting of an IC package. SOLUTION: With the socket for IC package provided with a pressure mechanism pressing and holding an IC package onto a socket main body with the contact state of its terminal and contact maintained, a normal coil spring 82 and a shape-memory coil spring 84 are set in combination as a pressing force changing means for differentiating a pressing force at normal temperature and that at burn-in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressing mechanism for pressing a semiconductor integrated circuit package (hereinafter referred to as an IC package) against a socket body while maintaining a predetermined contact pressure state between its terminals and contacts. The present invention relates to an IC package socket provided with.

[0002]

2. Description of the Related Art Generally, a so-called burn-in test is carried out for a test of an IC package (for example, a heat resistance test) in which an IC package is mounted in an IC package socket and placed in a heating furnace to determine whether the IC package is good or bad. Has been done.

In such a burn-in test, generally, an IC package is loaded into each of a plurality of IC package sockets arranged in a grid on a burn-in board,
This burn-in board is used in a burn-in test tank while the IC package is pressed against the socket body by a pressing mechanism that uses the restoring force of a normal spring to maintain the contact pressure between the terminal and the contact. It is done by inserting in. When the IC package is loaded, the socket cover is pressed against the spring force of the ordinary spring or the like by the robot arm or the like to open the contact and position the IC package terminal at a predetermined position. By releasing the pressing on the cover, the IC package is pressed against the socket body by the pressing mechanism, and the IC package is held while maintaining a predetermined contact pressure state between the terminal and the contact.

[0004]

However, in such a conventional pressing mechanism utilizing the restoring force of the ordinary spring, the pressing force is almost constant regardless of the temperature change, so that the high-temperature burn-in test is performed. A spring having a spring constant capable of obtaining the pressing force required in the tank must be used, and an excessive operating force is required at the time of loading the IC package, which is an operation at room temperature against the spring force of the spring. Will be done.

This is because the burn-in test tank uses a machine such as a blower for blowing heated air or a compressor for temperature control, and the vibration of such a machine is transmitted to the entire burn-in test tank and is temporarily pressed. If the spring force of the mechanism's spring is weak, the IC package may dance in the socket, and in the worst case, a phenomenon may occur in which the contact and the terminal of the IC package are momentarily separated from each other, and it may be erroneously determined to be poor conduction. Because there is.

[0006] In such a socket with a large spring force set, a large operating force is required when the IC package is loaded at room temperature. Then, the strength of the burn-in board itself in which a plurality of IC package sockets are arranged in a grid shape is also necessary. If the strength is not sufficient, the central portion and the peripheral portion of the burn-in board may have different bending amounts. As a result, the accuracy of the position of the socket deteriorates or the socket cannot be operated completely, which makes it difficult to load the IC package into the socket. Therefore, the number of IC packages arranged on the burn-in board is limited, and the burn-in test productivity is limited.

In view of the above, it is expected that an IC package socket that can obtain a sufficient pressing force at the time of burn-in and that can be operated with a small operation force at the time of loading the IC package.

It is an object of the present invention to provide an IC package socket that can meet such demands.

[0009]

SUMMARY OF THE INVENTION To achieve the above object, an IC package socket of the present invention is a pressing member for pressing an IC package against a socket body while maintaining a predetermined contact pressure state between its terminals and contacts. IC with mechanism
The package socket is characterized in that a pressing force changing means for changing the pressing force of the pressing mechanism between normal temperature and burn-in is provided.

The pressing force is greater at the time of burn-in than at room temperature.

The pressing force changing means may include a shape memory spring.

Further, the pressing force changing means may include a combination of an ordinary spring and a shape memory spring.

Further, the pressing mechanism may be a pressing member for pressing the body of the IC package.

Further, the pressing mechanism may be a pressing member for pressing the terminals of the IC package.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. In the following description, the same parts are designated by the same reference numerals to avoid redundant description.

1 to 9 show a first embodiment of an IC package socket according to the present invention. In this embodiment, the present invention is applied to a so-called BGA type IC package socket in which contact is made at two places on the left and right of the ball-shaped lead terminal BLT of the BGA type IC package ICP. .

FIG. 1 shows a rectangular IC package socket 1
0 is a plan view showing the whole of FIG. 0, FIG. 2 is a sectional view taken along the diagonal line X of FIG. 1 taken along the line II-II, and FIG. 3 is a sectional view taken along the center line parallel to the side taken along the line III-III of FIG. Is. Socket 10
Is basically a resin-containing base substrate 20 made of glass fiber.
And a cover member 4 provided so as to be slidable with respect to the base substrate 20 and also provided with a slide substrate 30 made of resin, and a cover member 4 arranged so as to be vertically movable with respect to the socket body.
It has 0 and.

A large number of contacts 50 are attached to the base substrate 20 in a grid pattern parallel to each side at the same pitch. Each of these contacts 50 elastically clamps the ball-shaped lead terminal BLT. Elastic contact piece 50
a and 50b (see FIGS. 5 and 8).

The slide substrate 30 is provided so as to be movable toward one corner of the base substrate 20 on the diagonal line X, and acts to elastically displace one elastic contact piece 50a during this movement. More specifically, the slide substrate 30 corresponds to the ball-shaped lead terminals BLT of the IC package and the grid-like arrangement of the contacts 50, and the contact accommodating holes 32.
And receives the elastic contact pieces 50a and 50b. A partition wall 34 that crosses the contact receiving hole 32 is provided between the elastic contact pieces 50a and 50b. Further, on the upper surface of the slide substrate 30, the IC package IC
A guide frame member 31 for guiding P to a predetermined mounting position is provided.

The slide substrate 30 is moved by a moving mechanism 60 described below. The moving mechanism 60 may be of a type provided with levers 61 and 62 known from Japanese Patent Application Laid-Open No. 10-302925 or the like, so only a brief description will be given. That is, as shown in FIG. 2, the moving mechanism 60 is rotatably attached to the base substrate 20 by the shafts 61A and 6A.
Levers 61 and 62 pivotally supported by 2A, and the levers 61 and 62,
Drive shafts 61B and 62B provided on the slide substrate 62, engagement grooves 35 and 36 formed on the slide substrate 30 with which the drive shafts 61B and 62B engage, and a spring 38 that biases the slide substrate 30 to the initial position. I have it. Although not shown, the levers 61 and 62 extend from the shafts 61A and 62A along the sides of the cover member 40, respectively. Incidentally, the shafts 61A, 6
The axes of 2A, the drive shafts 61B and 62B, and the engagement grooves 35 and 36 are all orthogonal to one diagonal line X of the base substrate 20.

A return spring 22 for urging the cover member 40 upward is provided between the base substrate 20 of the socket 10 and the cover member 40.

Next, referring to FIGS. 1, 3 and 6,
As a part of the pressing mechanism of the present invention, a pair of latch members 70 as pressing members are provided on the center lines of the two opposite sides of the socket 10 so as to be rotatable with respect to the base substrate 20. The latch member 70 has a pressing piece portion 70A that comes into contact with the upper surface of the IC package ICP and presses it, a pressed portion 70B that is pressed when the cover member 40 descends, and the pressed portion 70.
70C of spring seats formed on the lower side of B and the base substrate 2
The protrusion 7 that comes into contact with 0 and becomes the center of rotation of the latch member 70
It has 0D.

In this embodiment, the spring seat portion 70C is used.
Are arranged side by side in parallel with the sides of the socket 10 (see FIG. 9).
reference). The two spring seat portions 70C juxtaposed with each other are provided with a normal coil spring 82 made of a normal spring material or the like as a pressing force changing means for changing the pressing force of the pressing mechanism between normal temperature and burn-in. A shape memory coil spring 84 made of a shape memory material is provided in a pair with a spring seat 90 provided on the base substrate 20 in combination. The number of shape memory coil springs 84 combined with the normal coil spring 82 is not limited to one. However, it is necessary to have at least one conventional coil spring. This is because if both of them are shape memory coil springs, the proof stress at room temperature is insufficient, the springs remain deformed, and the IC package cannot be pressed.

Here, the normal spring has a constant spring constant regardless of temperature, and the shape memory spring changes its spring constant depending on the temperature due to the shape recovery action at a predetermined temperature.
A typical shape memory spring is composed of a shape memory material of Ni-Ti alloy, and the shape recovery temperature changes depending on the blending amount of Ni, but since the burn-in test is generally performed at 120 to 150 ° C, the shape memory spring at about 100 ° C is used. It is preferable to select a shape memory spring that recovers.

In this embodiment, the IC package I
To attach the CP to the socket 10, proceed as follows.

When the cover member 40 is pressed by the robot arm or the like without the IC package ICP shown in FIG. 2, the cover member 40 is lowered against the return spring 22 and the lever 61 is provided on the lower surface thereof. , 62 is pressed. The levers 61 and 62 rotate about the shafts 61A and 62A, and the drive shafts 61B and 62B engaged with the engagement grooves 35 and 36 formed in the slide substrate 30 cause the slide substrate 30 to move to the spring 38. Move against.
When the slide substrate 30 moves, the contact receiving hole 32
The elastic contact piece 50 a of the contact 50 is elastically deformed by the partition wall 34 that is provided across the contact 50.
Can be spread.

When the cover member 40 descends, the cover member 40 simultaneously pushes the pressed portion 70B of the latch member 70.
A normal coil spring 82 and a shape memory coil spring 84
Is pressed against the spring force to rotate the latch member 70 around the protrusion 70D, and the latch member 70 is opened as shown in FIG. Since the operation of mounting the IC package ICP in the socket 10 is performed at room temperature, the spring force of the shape memory coil spring 84 before shape recovery is weak and the pressing force of the robot arm or the like is small by that amount. It will be good. Therefore, even in a burn-in board in which a plurality of sockets 10 are arranged, the reaction force is small, and the amount of bending is small.

With the contact 50 expanded and the latch member 70 opened, the IC package ICP is loaded through the opening of the cover member 40. The introduced IC package ICP is guided to a predetermined mounting position by the guide frame member 31.

In this state, when the pressing force by the robot arm or the like is released, the cover member 40 is raised by the return spring 22 and the slide substrate 3
Zero is returned to the initial position by the spring 38 (see FIG. 7). Then, the lead terminal BL of the IC package ICP
As shown in FIG. 8, T is a pair of elastic contact pieces 50a, 50
It is elastically clamped by b, while IC package IC
As shown in FIG. 6, P is a pressing piece 7 of the latch member 70.
It is pressed against the slide substrate 30 which is the socket body by 0A. The pressing force at this time is the same as the normal coil spring 82 and the shape memory coil spring 84 before shape recovery.
Due to the spring force of.

When the mounting of the IC package ICP in the socket 10 on the burn-in board is completed, the burn-in board is inserted into the burn-in test tank and the test is performed at a predetermined high temperature. However, according to the present embodiment, in this high temperature state, the shape memory coil spring 84 recovers its shape and its spring constant becomes large, and the IC by the pressing piece 70A of the above-mentioned latch member 70 is increased.
Even if the pressing force on the package ICP increases and the analogy or vibration of the burn-in test tank occurs, the IC package I
It is possible to prevent the CP from dancing in the socket 10 and the momentary disconnection between the contact and the terminal of the IC package in the worst case.

Further, as a second embodiment of the present invention, as shown in FIG. 10, the spring seat 70C is attached to the latch member 7.
They may be juxtaposed in the direction orthogonal to the 0 rotation axis. And
The shape memory coil spring 84 is arranged at a position farther than the normal coil spring 82 with respect to the protrusion 70D forming the rotation axis. By doing so, the moment due to the shape memory coil spring 84 can be increased, so that it is possible to make the pressing force greatly different at room temperature and at burn-in. In other words, when each spring force is set so as to obtain a predetermined pressing force at the time of burn-in, it means that the operating force at room temperature can be made smaller.

In the above-described embodiment, the present invention is based on B
Although the example applied to the GA type IC package socket has been described, the present invention is not limited to this type of socket, and the main body of the IC package or the lead terminal may utilize the spring force even in other types. It is needless to say that the present invention can be applied to any type as long as it is held by pressing with a pressing mechanism.

[0033]

As is apparent from the above description, according to the present invention, an IC package socket that can obtain a sufficient pressing force at the time of burn-in and can be operated with a small operation force at the time of loading the IC package is obtained. be able to.

Therefore, it is possible to prevent the dance of the IC package and the momentary interruption of the contact by increasing the pressing force at the time of burn-in while keeping the operating force at the time of loading the IC package as it is.

Further, by making it possible to operate with a small operation force, it is possible to eliminate adverse effects on the burn-in board and the socket, and prevent an IC package loading error.

[0036]

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of an IC package socket according to the present invention.

FIG. 2 is a cross-sectional view taken along line II-II of the IC package socket of FIG. 1, showing a state in which the IC package is not mounted.

3 is a half cross-sectional view taken along the line III-III taken along a center line parallel to the sides of the IC package socket of FIG.

4 is a cross-sectional view of the IC package socket of FIG. 1 taken along the line X-II, showing a state where the cover member is lowered for mounting the IC package.

FIG. 5 is an enlarged view showing a relationship between a contact and a lead terminal, showing a state where the contact is expanded.

6 is a III-III line half cross-sectional view taken along a center line parallel to the side of the IC package socket of FIG. 1, showing a loaded state of the IC package.

7 is a sectional view taken along the line II-II of the IC package socket of FIG. 1 taken along a diagonal line X, showing a loaded state of the IC package.

FIG. 8 is an enlarged view showing a relationship between a contact and a lead terminal, showing a state in which the contact is closed.

FIG. 9 is a view showing the relationship between the latch member and the spring of the present invention.
FIG.

FIG. 10 is a cross-sectional view showing another relationship between the latch member and the spring of the present invention.

[Explanation of symbols]

10 IC package socket 20 base substrate 30 slide board 40 cover member 50 contacts 60 moving mechanism 70 Latch member 82 Normal coil spring 84 shape memory coil spring

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2G003 AC01 AG01 AG12                 2G011 AA08 AA15 AC14 AE22 AF02                 5E024 CA19 CB02

Claims (6)

[Claims] 1. An IC package socket having a pressing mechanism for pressing and holding an IC package against a socket body while maintaining a predetermined contact pressure state between its terminals and contacts, wherein the pressing force of the pressing mechanism is room temperature. A socket for an IC package, characterized in that a pressing force changing means is provided for differentiating between the time of burn-in and the time of burn-in. 2. The IC according to claim 1, wherein the pressing force is larger at the time of burn-in than at room temperature.
Package socket. 3. The IC package socket according to claim 1, wherein the pressing force changing unit includes a shape memory spring. 4. The pressing force changing means includes a combination of an ordinary spring and a shape memory spring.
Alternatively, the IC package socket described in 2. 5. The IC package socket according to claim 1, wherein the pressing mechanism is a pressing member that presses the main body of the IC package. 6. The IC package socket according to claim 1, wherein the pressing mechanism is a pressing member that presses a terminal of the IC package.