JPH1167400A - Ic socket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IC socket, which is used in electrical characteristics tests for a surface mounted type package IC, which can reduce the maintenance frequency of IC socket by suppressing the effects of a solder plating transferred to the IC socket and thereby enhancing the reliability upon the tests, and which enables transmission of more precise signals by lessening the L-component of the contacting piece. SOLUTION: An IC socket in which a surface mount type IC is mounted, has a rotary contacting piece 2 in a columnar shape to contact with a spring contacting piece formed from a resilient metal piece bent into a shape of inverted chevron. Because this is a mechanism for making rotation each time the rotary contacting piece makes a contact 2 to contact with the IC lead 5, the transfer of solder from the IC lead 5 is dispersed, to result in prolongation of the period until intermittent contact due to solder attachment is generated. Further it is possible to lessen the L-component as compared with a conventional contacting piece. Accordingly, the frequency for maintenance of IC socket can be reduced, and the measuring accuracy is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC socket, and more particularly, to an IC socket for testing electrical characteristics of a semiconductor device of a planar mounting type package.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a conventional IC socket.

As shown in FIG. 4, a conventional IC socket has a contact 8 bent to have a horizontal U-shape or C-shape (hereinafter referred to as a horseshoe shape) R, and a socket base on which the contact 8 is installed. 9 and a contact pusher (lid) 10. The contact 8 is made of a spring metal (Be-Cu).
Etc.) are plated with high conductivity (such as gold plating). Further, the socket base 9 and the contact pusher 10 are made of an insulator, and a plastic resin is generally used.

Next, a contact operation will be described. The lead 5 of the IC 6 to be measured is set on the contact 8 by manual operation or by an automatic machine. Thereafter, the IC lead 5 is pushed down in the direction of the contact 8 by the contact pusher 10. The amount of depression depends on the shape of the contact, but is generally between 0.2 mm and 0.7 mm. This pressing action generates a repulsive force of the spring of the contact 8 (about 20 to 50 g), and this force causes the contact 8
And the IC lead 5 come into electrical contact. Also,
Since the contact 8 is formed so that stress concentrates near the center of the horseshoe-shaped R, the contact pusher 10 pushes down the contact 8 via the IC lead 5 so that an arc around the stress concentration portion is formed. Designed to exercise. Therefore, the point at which the IC lead 5 and the contact 8 are in contact differs between when the IC lead 5 is set and when the IC lead 5 is pressed down by the contact pusher 10. In short, the contact 8 is moving at the contact point while sliding on the lower surface of the IC lead 5. This operation (hereinafter referred to as wiping)
This has the effect of reducing the contact resistance such as the breakdown of the oxide film on the IC lead 5.

[0005] The above-described technique is a general IC socket, but an IC socket having a contact for making surface contact to suppress damage to the IC lead 5 due to wiping has also been devised. For example, it is described in JP-A-7-22135.

[0006]

The first problem is that the solder plating transferred from the IC to be measured causes a short circuit between the contacts of the IC socket and a poor contact between the IC lead and the IC socket contact. It is. In addition, in order to suppress such problems, regular maintenance (cleaning and replacement of the IC socket, etc.) is performed.

The following factors exist as the reason. I
The contacts of the C socket wipe the IC leads. This has an advantageous effect on electrical contact, such as destruction of an oxide film on the surface of the IC lead, but at the same time causes a reduction in solder plating on the IC lead. The scraped solder plating may remain on the IC lead as it is or transfer to the contact of the IC socket. Then, as the number of insertions of the IC increases, the amount of solder transferred to the contacts of the IC socket increases and short-circuits with the adjacent contacts. Further, when the solder adheres to the contact, the contact resistance between the IC lead and the contact increases, resulting in a contact failure in which normal electrical contact cannot be performed.

As a countermeasure, if the solder attached to the IC socket is removed, the above problem can be solved. However, there is a problem that the equipment must be stopped to clean the IC socket or replace the IC socket. Further, there is a problem that the number of working steps must be secured.

[0009] The second problem is that the L component is 10 nH or more, and the reliability of measurement in a high frequency band (100 MHz or more) cannot be maintained.

[0010] The reason is that the distance from the contact point between the contact and the IC lead to the printed circuit board on which the actual IC socket is mounted is long. that is,
This is because the contact has a horseshoe shape so as to have a spring property. Because the contact pusher is I
This is because the repulsive force generated when the contact is depressed via the C lead is minimized to damage to the IC lead, and is a force that enables stable electrical contact.
Generally, the force is between 20g and 50g. In the case of the horseshoe shape, the stress is concentrated at the center of the R because of the R structure, but the stress is also dispersed in the entire R portion. Therefore, a certain length is required to secure an appropriate spring constant. When the thickness of the contact is reduced, the spring constant is reduced and the length can be reduced, but the L component hardly changes. Therefore, even if the thickness and length of the contact are changed to provide a suitable repulsive force, the L component becomes 10 nH or more.

A third problem with the surface contact type contact is that it is difficult to make stable contact between the IC lead and the contact.

[0012] The reason for this is that variations in the IC lead thickness cannot be absorbed, and only the pressing of the thickest contact can be performed. The thickest IC lead is normally sandwiched between the contact pusher and the surface contact, while the thinnest IC lead has a gap between the contactor and the contact pusher due to variations in IC lead thickness. Since a normal contact force is not applied to the child, poor contact is likely to occur.

The present invention has been made in view of the above points, and has been made in consideration of the electric characteristics test of a surface mount type package IC, by suppressing the influence of solder plating transferred to an IC socket and improving the reliability of the electric characteristics test. By improving
An object of the present invention is to provide an IC socket capable of reducing the frequency of maintenance of the IC socket and reducing the L component of the contact, thereby enabling more accurate signal transmission.

[0014]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an IC socket for mounting a surface mount type IC, a rotating contact contacting an IC lead, and a spring contact contacting the rotating contact. And characterized in that: Further, the present invention is characterized in that the rotary contact is cylindrical. Further, the present invention is characterized in that the spring contact is formed by bending a resilient metal into an inverted C shape.

As a result, in the IC socket of the present invention, the contact point of the rotary contact at the contact between the IC lead and the IC socket moves. Thereby, I
There is an effect that the portion where the solder is transferred from the C lead is dispersed. Furthermore, by using the inverted C-shaped leaf spring,
Since the signal can be transmitted at the shortest distance, there is an effect of reducing the L component of the contact.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 will be described.

FIG. 1 is a sectional view of an IC socket for a surface mount type package according to the present invention.

The IC socket according to the present invention comprises a spring contact 1 bent in an inverted C shape, a rotary contact 2 mounted in the inverted C shape, a socket base 3 for installing them, and And a contact pusher 4.

The spring contact 1 is made of a springy metal (eg, Be)
-Cu or the like, which is subjected to highly conductive plating (eg, gold plating). Further, the spring contact 1
Has a structure in which it is bent in an inverted C shape inside the IC socket and has a socket terminal for transmitting a signal to the outside of the IC socket. Further, the tip of the spring contact 1 is bent inward to prevent the rotating contact 2 mounted therein from jumping out. The material of the rotary contact 2 is not particularly limited, and in this embodiment, the same Be-Cu as the spring contact 1 is used.
Made with However, since the circumference of the rotary contact 2 needs to be plated with high conductivity, gold plating is applied in this embodiment. The rotary contact 2 is mounted in the inverted C shape of the spring contact 1, and electrical contact is established.

The socket base 3 is made of an insulator and is made of a plastic resin in this embodiment, and is for the purpose of installing the spring contact 1, so that the shape can be freely selected according to the method of use. The contact pusher 4 moves the lead 5 of the IC 6 toward the contactor by an appropriate amount (from 0.2 mm to 0.5 mm).
It is structured so as to be pressed by the same amount, and the material is an insulator. In this embodiment, the same plastic resin as that of the socket base 3 is employed. The amount of the press depends on the spring coefficient of the spring contact 1, but it is designed such that the reaction force is about 20 to 30 g by the press of about 0.2 to 0.5 mm. Such pushing amount and reaction force are common, but there is no problem even if they are changed. The reaction force, that is, the spring coefficient is determined by the thickness and the bending angle of the spring contact 1, but in this embodiment, it is easy to manufacture the spring contact 1 with a short length of about 1 mm. Unlike conventional horseshoe-shaped R-structures, stress is dispersed to some extent, and processing is performed to make corners, so stress is concentrated at one point and a relatively small spring coefficient can be achieved. Because.

Next, the operation of the IC socket according to the present invention will be described.

FIG. 2 is an explanatory diagram of the component force at the time of contact in the embodiment of the present invention shown in FIG.

The IC 6 of the surface mount type package is set in the IC socket by a manual operation or an automatic machine (IC
The lead 5 is placed on the rotary contact 2). Thereafter, the IC lead 5 is pushed toward the contact by the contact pusher 4. At this time, as shown in FIG. 2, the tip of the lead is at an angle with respect to the mounting surface of the IC socket (design value is 3 degrees, generally 0 to 7 degrees with a tolerance).
Instead of pressing the contact just above the center of the circle (in the moving direction of the contact pusher 4), a point slightly shifted is pressed via the IC lead 5. that is,
The component is divided into a tangential direction and a central direction, and the tangential force is a force for rotating the rotary contact 2. Therefore, when the IC lead 5 is pushed, the rotary contact 2 rotates. That is, each time the IC lead 5 makes contact with the rotary contact 2, the rotary contact 2 rotates and has a contact point for the circumference of the rotary contact 2. Also, IC
The lead 5 establishes electrical contact with the spring contact 1 via the rotary contact 2, and furthermore, electrical contact with external equipment becomes possible.

FIG. 3 is a sectional view of another embodiment of the present invention.

The embodiment of FIG. 3 is generally the same as the embodiment of FIG. 1, but shows only the different points in an enlarged manner. That is, the projection 7 is provided on the inner surface of the spring contact 1 (the surface facing the rotary contact 2). The shape of the projection 7 is a file shape or a saw blade shape (FIG. 3). This projection 7
The rotation of the rotary contact 2 can provide an effect of scraping off the solder attached to the surface of the rotary contact 2. This solder has been described as the first problem of the "problem to be solved by the invention", and this can be solved by the embodiment of FIG.

[0027]

The following effects can be obtained by the IC socket of the present invention having the structure described above.

The first effect is that a surface mount type package IC is used.
An object of the present invention is to reduce the frequency of maintenance of the IC socket by suppressing the influence of the solder plating transferred to the IC socket and improving the reliability of the electrical property test. The effect varies depending on the processing capacity of the IC tester.
It is possible to obtain the effect of reducing the required equipment stoppage time and man-hours to one-tenth or less.

The reason for this is that the contact portion of the contact is the length of the circumference of the rotary contact, and the size of the solder attached to the contact is dispersed by the circumference. That is, while the conventional contact always has a contact point at the same position, the contact point has a length of about 0.5 mm, whereas in the present invention, the length of the circumference of the rotating contact is used. This is because contact becomes possible. If the diameter of the rotary contact is designed to be 2 mm, the circumference becomes 6 mm or more, and the influence of solder can be suppressed to 1/10 or less.

The second effect is that the L component of the contact of the IC socket can be suppressed to half or less of the conventional (about 10 nH).

The reason for this is that, in contrast to a conventional horseshoe shape in order to have a spring property, the length of the contact itself can be reduced by processing the leaf spring into an inverted C shape. It is. That is, since the dispersion of the stress due to the conventional R structure can be reduced by performing a bending process in which the leaf spring has a corner, it is possible to shorten the length of the spring portion and secure an appropriate constant. It is. Thereby,
It is also possible to halve the length of a conventional contact.

[Brief description of the drawings]

FIG. 1 is a sectional view of an IC socket for a surface mount type package according to the present invention.

FIG. 2 is an explanatory diagram of a component force at the time of contact in the embodiment of the present invention shown in FIG.

FIG. 3 is a sectional view of another embodiment of the present invention.

FIG. 4 is a sectional view of a conventional IC socket.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spring contact 2 Rotary contact 3 Socket stand 4 Contact pusher 5 IC lead 6 IC 7 Projection 8 Contact 9 Socket stand 10 Contact pusher

Claims (6)

[Claims] 1. An IC socket for mounting a surface-mounted IC, comprising: a rotary contact that contacts an IC lead; and a spring contact that contacts the rotary contact. 2. The IC socket according to claim 1, wherein said rotary contact has a cylindrical shape. 3. The IC socket according to claim 1, wherein the spring contact is formed by bending a resilient metal into an inverted C shape. 4. The IC socket according to claim 1, wherein said spring contact has a tip bent inward to prevent a rotating contact mounted therein from jumping out. 5. The IC socket according to claim 1, wherein a projection is provided on an inner surface of the spring contact. 6. The IC socket according to claim 5, wherein said projection has a saw blade shape.