JP2008123978A - Socket for electric test of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a socket for an electric test of a semiconductor device capable of reducing bending stress in a plate spring type contact, and of satisfying a requirement of high contact force exceeding 300 gf per contact pin. <P>SOLUTION: This socket for an electric test of a semiconductor device comprises: a base member comprising a bottom part, a side part and a semiconductor device mounting part; plate spring contacts and coil springs each having one end fixed to the bottom part of the base member; and latches 30 rotatably attached to the base member; and is structured such that the other end of each coil spring is fixed to the bottom surface of a pressing part of the latch, and the latch is attached such that a tip part of the latch comes into contact with a tip part of the plate contact at least in terminating the pressing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a socket for a semiconductor device (hereinafter sometimes referred to as a package) used for inspection of a semiconductor device, and more specifically, for example, an electrical of a semiconductor device having a lead-like external terminal called a DIP or SOJ type. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for performing a physical characteristic inspection, and more particularly to a test socket for performing an electrical inspection of a semiconductor device, which uses a spring force of a coil spring and transmits the result by a latch mechanism.

  For example, in order to perform an electrical inspection of a semiconductor device in which lead-like external terminals (= lead terminals) such as DIP and SOJ type are drawn horizontally from opposite side surfaces of the semiconductor device and bent vertically, a metal is used. Test sockets (hereinafter referred to as “sockets”) using leaf spring type contacts in which plates are punched out by press working have been widely used in the past, and are the most common method in recent years.

  The prior art will be described with reference to FIG. FIG. 7 is a cross-sectional view showing a main part of a conventional socket using a leaf spring type contact (hereinafter sometimes referred to as a leaf spring contact or a contact), and shows a state in which the semiconductor device 11 is mounted. It is a schematic diagram which shows the connection between the semiconductor device 11 with which the mounting part 24 of the base member 20 of the socket was mounted | worn, and the test circuit board 13 of a measuring device. The contact 40 is assembled to the socket base member 20 by a contact fixing portion 44 corresponding to the pitch and the number of arrangement of the lead terminals 12 of the semiconductor device, and the solder lead portion 45 of each contact is inspected by the measuring device. It is fixed to the electrode pattern of the circuit board 13 with solder. The contact is brought into contact with the lead terminal 12 of the semiconductor device by the spring tip 42 by the spring force of the spring elastic portion 41, so that the semiconductor device is electrically connected to the test circuit board through the socket. The contact material is generally made of beryllium copper, which has a high spring limit and is difficult to loosen.

  Essentially important in sockets is to achieve a reliable and stable electrical connection. Therefore, it is necessary to design the material / material, shape, and spring property of the socket contact in accordance with the temperature and environment in which it is used. For the design of the spring part of the contact, various copper alloy materials and materials excellent in elasticity and conductivity are used. Also in the design of the spring part, various curved parts can be seen. A characteristic point common to the prior art is that the spring force is designed and formed by using the spring force of the contact itself.

  However, the sockets using the leaf spring type contacts that have been used most often have the following problems.

The first problem is that the contact relies on its own elastic deformation, and as a result of repeated bending bending stresses, the spring elastic portion tends to be permanently deformed, resulting in a loss of reliable electrical testing.
The second problem is usually about 30 gf of contact force per pin of contact, but from the viewpoint of improving contact resistance, there is a tendency for a demand for higher contact force than before, and the conventional leaf spring type contact. It was difficult to deal with.
The third problem is that the external terminal may be covered with a thin film (= insulator) of the mold resin depending on the molding situation at the time of manufacturing the semiconductor device. In some cases, solder plating of the external terminals forms natural oxide and forms an insulating oxide film. In such a case, a contact force of 100 to 300 gf, which is higher than usual, is required, and the bending stress generated in the contact is excessive for such a request, and it is extremely difficult to cope with the conventional leaf spring type contact. there were.

  The present invention has been made to solve the above-described problems. That is, by significantly reducing the bending stress generated in the contact, it is possible to ensure a reliable and stable contact force over a long period of time, and to provide a socket for an electrical test of a semiconductor device that achieves a higher contact force than before as required. That is.

The present inventor reduces the bending stress of the contact to 1/10 or less of the conventional one by incorporating a latch mechanism comprising a fulcrum, an action point, and a force point into the socket by using the spring force of the coil spring, and in addition to 300 gf or more. The present invention has been completed by realizing a high contact force and finding that the above-mentioned problems can be solved.
That is, the present invention provides the following inventions.
(1) A base member comprising a bottom portion, a side portion, and a semiconductor device mounting portion, a contact and a coil spring having one end fixed to the bottom portion of the base member, and a latch rotatably attached to the base member. The other end of the semiconductor device is fixed to the bottom surface of the pressing portion of the latch, and the latch is attached so that the front end of the latch contacts at least the front end of the contact when the pressing is released.
(2) The electrical test socket for a semiconductor device according to (1), wherein a stopper is provided on a side of the base member, and a stopper notch is provided on the latch.
(3) The electrical test socket for a semiconductor device according to (1) or (2), wherein a shaft is provided on opposite sides of the base member, and a latch is held on the shaft.

(A) According to the present invention, by using the spring force of the coil spring and the latch, the bending stress of the contact is significantly reduced to 1/10 or less of the conventional one. Therefore, there is an effect that the life of the contact is extended and a stable and reliable electrical test can be performed over a long period of time.
(B) According to the present invention, by using the spring force of the coil spring, it is possible to realize a high contact force exceeding 300 gf per pin, which has been difficult in the past, while greatly reducing the bending stress of the contact. effective.
(C) According to the present invention, the present invention can also be applied to a package type in which lead terminals are arranged on the four outer sides of a semiconductor device.

The semiconductor device electrical test socket of the present invention includes a base member and a contact as in the conventional socket, and further includes a coil spring and a latch. The latch is attached to the base member so as to be rotatable, and the spring force of the coil spring is transmitted to the contact through the latch to assist the contact between the contact and the lead of the semiconductor device.
As a method of attaching the latch to the base member so as to be rotatable, there is, for example, a method of holding the latch rotatably on a shaft installed in a shaft hole provided on the left and right side surfaces of the base member. However, the method is not limited to this method as long as the spring force of the coil spring is transmitted to the contact.

  Hereinafter, embodiments of the present invention using the above-described shaft will be described with reference to the drawings. FIG. 1 is a perspective view showing a socket according to an embodiment of the present invention. FIG. 2 is a perspective view showing the configuration of the socket according to the embodiment of the present invention. FIG. 3A is a perspective view showing the configuration of the socket according to the embodiment of the present invention, and shows a state in which the semiconductor device is not mounted. 3b is a cross-sectional view taken along line AA and BB in FIG. 3a. The left half of FIG. 3b is a cross-sectional view taken along the line AA, and the right half is a cross-sectional view taken along the line BB. Indicates the part. 4 is a cross-sectional view taken along the line B-B in FIG. 3A and shows a state in which the semiconductor device is not mounted. FIG. 5 is a cross-sectional view taken along the line B-B in FIG. Indicates the state. 6A is a plan view of a leaf spring contact according to the present invention, and FIG. 6B is a partially enlarged cross-sectional view of FIG. 5, showing the relationship between the lead terminal, contact and latch of the semiconductor device. FIG. 7 is a cross-sectional view showing a main part of a conventional socket.

  FIG. 1 is a perspective view showing an embodiment of an inspection socket 10 of a semiconductor device incorporating a latch 30 and a coil spring 36 of the present invention, and shows a state in which the semiconductor device 11 is mounted. In addition to the base member 20 and the contact 40 (see FIG. 7) that are also used in conventional sockets, the main part of the inspection socket is made of a metal, for example, stainless steel, that serves as the rotation shaft of the latch 30, the coil spring 36, and the latch. Shaft 35 (see FIG. 2). In FIGS. 1 to 7, since the semiconductor device is a type having two rows of lead terminals on both side surfaces, two sets of the above-described configuration are arranged. Depending on the type of package of the semiconductor device, there are those having the number of arrays of 4 rows or 1 row on the outer periphery 4 sides, but according to the present invention, it can be applied to all the numbers of rows by arranging with the above-mentioned configuration for each array Is possible. The characteristic point of the present invention is that a latch and a coil spring are arranged corresponding to each contact, and the spring force of the coil spring is transmitted to the contact via the latch without depending on the spring force of the contact.

  An outline of the constituent parts will be described with reference to FIG. Further details will be described later with reference to FIGS. In connection with the present invention, there is no significant change from the conventional socket in terms of the material / material and outer dimensions of the socket base member 20 and the layout of the printed wiring board. The base member has substrate mounting holes 21 at two diagonal corners into which screws for fixing to the printed wiring board are inserted. It has a guide 23 and a mounting portion 24 for mounting a semiconductor device to be described later, and a contact fixing groove 22. These are designed with an emphasis on compatibility with the prior art. Insulating mold resin is generally used for the socket member, but the base member and the latch have no problem using these general materials in the present invention.

In FIG. 2, the coil spring 36 and the latch 30 according to the present invention will be described in relation to the base member composed of the bottom portion 28, the side portion 29, and the mounting portion.
1 to 3, preferably 2 to 3, holes 27 for accommodating the coil springs 36 are provided on opposite sides of the base member bottom portion 28 with the mounting portion of the semiconductor device interposed therebetween. In this figure, two coil springs are used in three holes. The number of coil springs used on each side is preferably at least two in order to transmit the spring force evenly to a latch described later. In order to satisfy the requirement of higher contact force than usual, three is more preferable. To make this choice possible, the holes are made in three places. The upper end of the coil spring is held from above and below by being housed in a coil spring hole 37 (see FIG. 3) provided in a latch described later.

The coil spring is not special, and its dimensions and strength may be selected from commercially available products. The strength is calculated by multiplying the contact force per pin by the number of poles, and taking into consideration the ratio of the distance from the fulcrum and the point of action, which is the principle of latch levers, which will be described later. This will be described in detail in the section on latches.
In the present invention, the life of the socket depends on the life of the coil spring in that the load of the bending stress of the contact is greatly reduced by utilizing the spring force of the coil spring. Therefore, it is preferable to select a coil spring that emphasizes durability.
Further, since the lower end of the contact is soldered to the board, if the contact is defective, the replacement work is difficult, and the entire socket becomes unusable. According to the present invention, the load on the contact is greatly reduced, and the replacement of the coil spring is relatively simple, so that the life of the entire socket is extended.

A latch 30 is used to transmit the spring force of the coil spring to the contact. The latch includes a latch pressing portion 31, a through hole (= fulcrum) 32, a contact positioning groove (= action point) 33, a latch stopper notch 34, and a coil spring accommodating hole (= force point) 37 (see FIG. 3b). The If the semiconductor device has two rows of lead terminals on both sides, two sets of latches are prepared. In short, prepare the same number of contacts as the number of contacts.
In the surface that engages with the contact in the pitch direction, a contact positioning groove 33 is provided in the center portion in accordance with the pitch and the number of poles to correct the contact collapse or misalignment. Latch stopper cutouts are provided on the left and right ends. This will be described later with reference to FIG.

The latch 30 has a through hole (= fulcrum) 32 penetrating in the pitch direction, and a metal shaft 35 is inserted into this hole, and the latch is fixed to the shaft hole 25 on the side of the base member so as to be rotatable. .
The latch is rotatable with a metal shaft inserted into the through hole as a fulcrum, and the spring force of the coil spring is transmitted to the contact protrusion 46 via the contact positioning groove 33 as the point of action with the coil spring accommodating hole 37 as a force point. Is done. By setting the length between the fulcrum and the force point to be longer than the length between the fulcrum and the action point, a large output can be obtained with a relatively weak spring force of the coil spring. In the inspection process using the socket, when the semiconductor is attached or detached, the latch pressing portion 31 is pressed against the spring force of the coil spring and pressed. Therefore, it is preferable that the coil spring is as weak as possible in terms of reducing the operating force.

FIG. 3A is a perspective view showing the configuration of the socket according to the embodiment of the present invention, and shows a state in which the semiconductor device is not mounted. 3b is a cross-sectional view taken along line AA and BB in FIG. 3a. The left half of FIG. 3b is a cross-sectional view taken along the line AA, and the right half is a cross-sectional view taken along the line BB. Indicates the part.
The coil spring is held from above and below by a coil spring accommodating hole 37 of the latch and a coil spring hole 27 at the bottom of the base member. Due to the spring force of the coil spring, the latch tries to rotate in the direction of pushing toward the protrusion 46 of the contact. The latch cutout in the left half, which is a cross section taken along the line AA, defines the original position of the latch. That is, the latching notch 34 and the stopper 26 of the base member determine the original position of locking. At this original position, the latch is in a state of pushing the contact at the central portion of the cross section taken along the line BB, and the contact portion 43 of the contact uses the contact force designed when the semiconductor device is seated on the mounting portion 24 as the lead terminal. It is in the position to press.

In the inspection of the semiconductor device, the process of attaching / detaching the semiconductor device to / from the socket and the current-inspecting process are sequentially repeated, which will be described with reference to FIGS.
4 is a cross-sectional view taken along the line BB of FIG. 3A and shows a state before the semiconductor device is mounted. When the semiconductor device 11 is inserted into the socket, the contact tip portion 42 protrudes to an interfering position. Therefore, by pressing the latch pressing portion 31, the contact tip portion is retracted in a direction away from the placement portion 24. Prepare to accept semiconductor devices.
FIG. 5 is a cross-sectional view taken along the line B-B in FIG. 3A and shows a state where the semiconductor device is mounted on the mounting portion. The latch returns to its original position by releasing the pressing of the pressing portion 31 that is the power point of the latch, and the contact portion 43 of the contact contacts the lead terminal of the semiconductor device.

The contact 40 will be described with reference to FIGS. 6a and 6b. 6A is a plan view of a contact according to the present invention, and FIG. 6B is a partially enlarged cross-sectional view of FIG. 5, showing the relationship between the lead terminal, contact, and latch of the semiconductor device. In FIG. 6a, the contact includes a spring elastic part 41, a tip part 42, a contact part 43, a fixing part 44, a soldering lead part 45, and a protrusion 46 behind the tip part. The fixing portion is fixed to the contact fixing groove of the base member. The spring elastic portion elastically deforms to generate a spring force, and the tip portion functions as a rigid body and has a contact portion that engages with a lead terminal of the semiconductor device at a part thereof. The protrusion is a portion that engages with the latch according to the present invention. In FIG. 6b, the tip of the contact is pushed by a latch from behind and engages with the lead terminal of the semiconductor device seated on the mounting portion. If there is no protrusion, the place where the latch and the contact are engaged varies and the performance becomes unstable. Therefore, it is preferable to provide the protrusion.
There is no problem by using beryllium copper which has been generally used as a contact material.

According to the invention, the bending stress of the contact is greatly reduced, which is illustrated in FIGS. 6a and 6b. The contact is fixed to the base member in the shape of FIG. 6A, and the original position of the tip is in a retracted position away from the mounting portion described above with reference to FIG. According to the present invention, the spring force is formed by the coil spring, and is transmitted to the protrusion of the contact by the latch. In FIG. 6b, the contact portion press-contacts the lead terminal while the tip portion slightly rotates with the protrusion portion of the contact as a fulcrum. The maximum load applied to the contact is due to the elastic deformation that occurs in the spring elastic part when supporting a slight rotational movement of the tip part, which is 1/10 or less compared to the prior art.
Further, according to the present invention, it is easy to cope with a contact force that is significantly higher than the conventional one that exceeds 300 gf per contact pin. By increasing the strength of the coil spring, a high contact force can be realized while reducing the load on the contact.

  The socket using the coil spring and the latch according to the present invention can greatly reduce the bending stress of the contact and can obtain a higher contact force than before, so that the reliability of the electrical test can be improved over the long term. The utility value is extremely large.

It is a perspective view which shows the socket concerning implementation of this invention. It is a perspective view which shows the structure of the socket concerning implementation of this invention. These are perspective views which show the socket concerning implementation of this invention, Comprising: The semiconductor device is not mounted | worn. Fig. 3a is a cross-sectional view taken along line AA and BB of Fig. 3a, in which the left half shows a notch for a stopper of the latch and the right half shows a central portion of the latch. FIG. 3B is a cross-sectional view taken along the line B-B in FIG. FIG. 3B is a cross-sectional view taken along line B-B in FIG. These are the top views of the leaf | plate spring contact concerning this invention. FIG. 5 is a cross-sectional view showing an engagement relationship between a leaf spring contact and a lead terminal and a latch of a semiconductor device. It is sectional drawing which shows the principal part of the conventional socket, Comprising: The state with which the semiconductor device was mounted | worn is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Socket 11 Semiconductor device 12 Lead terminal 13 Test circuit board 20 Base member 21 Board mounting hole 22 Contact fixing groove 23 Guide 24 Placement part 25 Shaft hole (= Latch fulcrum)
26 Stopper 27 Coil spring hole 28 Bottom 29 Side 30 Latch 31 Latch pressing part 32 Through hole (= Latch fulcrum)
33 Contact positioning groove (= Latch operating point)
34 Notch for latch stopper 35 Metal shaft (= Latch fulcrum)
36 Coil Spring 37 Latch Coil Spring Housing Hole (= Latch Force)
40 Contact 41 Spring elastic part 42 Tip part 43 Contact part 44 Fixing part 45 Soldering lead part 46 (corresponding to the action point of the latch)

Claims (3)

  A base member comprising a bottom portion, a side portion, and a semiconductor device mounting portion; a leaf spring contact and a coil spring having one end fixed to the bottom portion of the base member; and a latch rotatably attached to the base member. A socket for electrical test of a semiconductor device, wherein the other end is fixed to the bottom surface of the pressing portion of the latch, and the latch is attached so that the front end portion of the latch contacts at least the front end portion of the leaf spring contact when the pressing is released.   The electrical test socket for a semiconductor device according to claim 1, wherein a stopper is provided on a side portion of the base member, and a stopper notch is provided on the latch.   The electrical test socket for a semiconductor device according to claim 1, wherein a shaft is provided on opposite sides of the base member, and a latch is held on the shaft.

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