JP2001133500A - Electronic parts-measuring tool and electrode used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve measurement reproducibility by improving the contact electrode with the DUT of an electronic parts-measuring tool. SOLUTION: The electrode according to the present invention being used for the electronic parts-measuring tool is fixed to the electronic parts-measuring tool so that it projects from a DUT installation surface for installation, and a sculptured surface such as a columnar shape and a spherical one is provided at a surface region in contact with a DUT 51. When load is applied while the DUT 51 is installed at the surface region, a region in contact with the DUT is slightly and elastically deformed, thus obtaining a large face pressure with a relatively small load and stabilizing contact resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig for measuring a chip-shaped electronic component having no terminal lead wire, such as an SMT device, and more particularly to a jig for contacting each terminal of the chip-shaped electronic component. It concerns an electrode.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 1, a jig for measuring a three-terminal SMT device has a clip for supporting a device under test (hereinafter, referred to as a DUT) 11 by sandwiching each terminal portion thereof. Means 12 were provided. Therefore, the clipping means 12 functions as a measuring electrode, and the jig body 13 is connected to the measuring instrument via the connector 14, whereby the measuring circuit shown in FIG. 2A is formed. However, in this configuration, as shown in the figure, there is an inductance L due to the length of the clip, which is
2 is combined with the load capacitance C and the clip resistance R of FIG.
(B), the impedance Z1 enters in parallel with the vibrator. In the impedance measurement using a high-frequency signal, the inductance cannot be ignored, so that an error is caused in the measurement result.

On the other hand, in order to eliminate such errors, D
A method has been proposed in which a UT is soldered directly to a DUT board made to satisfy the same conditions as the conditions under which it is used for measurement. In this case, the error in the obtained measurement data is minimal, but depending on the type of DUT, the required form of connection to the measuring device differs depending on the type of the measurement parameter. As a device that requires a plurality of connection forms to the measuring instrument, for example, a ceramic resonator used for clock oscillation of various microcomputers can be cited.
As shown in (a), three elements including two load capacitances and one resonator are included in the measurement. In this case, in order to perform these measurements, 3
Three connection modes are required (the method of measuring the DUT using the three connection modes is described in detail in Japanese Patent Application Laid-Open No. 8-292219). Therefore, in order to measure each of the three elements, a dedicated DU for each measurement with different wiring is required.
I have to replace it with a T board.

Incidentally, as a means for changing the connection mode of the DUT to the measuring instrument, a mode in which a switch box is provided and a measurement path is switched in the switch box as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-292219 is disclosed. Are well known. However, DUT terminal jig (switch box)
The connection to the
The problem of how to fix the UT to the electrodes still exists.

Further, the measuring jig using the above-mentioned soldering method not only has the disadvantage of complicating the measuring procedure and increasing the cost, but also directly solders to the measuring jig such as a DUT board. For example, since the DUT cannot be used as a product, it has a fatal problem that it is practically useless for testing in a mass production line.

[0006] As a measuring jig capable of performing measurement by exchanging the DUT, the DUT is placed on an electrode group provided on the measuring jig and pressed from a surface opposite to a surface in contact with the electrode group. A measuring jig provided with a member has been generally known. Often the issue in this regard is the DUT
Is the contact resistance between the terminal and the electrode of the measuring jig. Incidentally, this contact resistance has such a property that when the surface pressure at the contact surface becomes larger than a certain threshold value, it does not change any more. Therefore, as a method for obtaining a stable contact resistance, a method of obtaining a desired surface pressure by increasing the load applied to the DUT so that the surface pressure reaches the threshold value can be considered. However, since the SMT type device has a flat electrode, it has been difficult to obtain a sufficient surface pressure with a conventional flat electrode on a measuring jig. This surface pressure is generally
It can be obtained by (the load M pressed from the upper surface of the DUT) / (the area S where the DUT electrode contacts the measuring jig electrode).
The load M is limited by the allowable load of the DUT.
On the other hand, with respect to the area S, it is conceivable to increase the surface pressure by reducing the area S. However, when the electrode is flat, it is generally considered that the terminal surface of the DUT contacts the flat portion of the electrode. The contact pressure changes drastically when it comes into contact with the corner of the end of the DUT, and the contact resistance greatly differs depending on the installation condition of the DUT. In particular, the area S of this planar electrode
Is too small, the DUT tends to come off the electrode.
Therefore, in order to stably fix the DUT to the jig, a minimum necessary area must be secured, and there is a limit in reducing the area of the plane electrode. Even if the load is within the allowable load range of the DUT, simply increasing the load may cause a change in the measured value, and the pressing structure itself of the measuring jig may be complicated and large. turn into. Therefore, in the conventional configuration, a sufficient contact surface pressure required under the condition that a minute high-frequency current is used as a measurement signal cannot be obtained, and it is difficult to maintain measurement reproducibility.

As described above, in the prior art, the exchangeability of the DUT and the improvement of the measurement accuracy and the measurement reproducibility are in a contradictory relationship, and there has been no means for realizing both of them at the same time.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention improves the structure of an electrode which is an electrical contact portion with a terminal of a DUT in an electronic component measuring jig, facilitates installation of the DUT, and stabilizes contact resistance. The purpose is to be.

Another object of the present invention is to provide an electronic component measuring jig having a wide range of application, which can provide stable contact with SMT devices of various sizes and shapes.

[0010]

In order to achieve the above object, an electrode according to the present invention for obtaining contact with a terminal of a DUT by using a jig for measuring an electronic component has the following structure. did. That is, it is fixedly installed on the electronic component measuring jig so as to protrude from the surface on which the device under test (DUT) is installed, and the surface area that can come into contact with the DUT has a curved surface shape. When a load is applied in a state of being set in the region, the region in contact with the DUT undergoes elastic deformation. Further, according to the present invention, the surface region can be formed in a cylindrical shape. Alternatively, the surface area can be spherical. Further, as an embodiment of the cylindrical electrode according to the present invention, the electrode may be formed of a cylindrical wire bent in a rectangular shape, and a central section thereof may have a contact area with the DUT. Further, as one embodiment of the spherical electrode according to the present invention, it is also possible to form a pin-shaped member having a spherical shape at the distal end so that the distal end has a contact area with the DUT. Further, by employing these electrode structures and further providing a pressing means for pressing the DUT against these electrodes, an electronic component measuring jig with improved measurement stability can be realized. For example, DU
The three-terminal device is stably installed by arranging the two cylindrical electrodes in a line on the T installation surface and arranging the one spherical electrode at a point equidistant from the opposite ends of these electrodes. In addition, it is possible to realize an electronic component measuring jig capable of covering devices of various sizes in a certain range.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS The presently preferred embodiment will now be described in detail with reference to the drawings. Note that components denoted by the same reference numerals in the drawings have the same function throughout the drawings.

An embodiment in which the present invention is incorporated in a jig for measuring the above will be described below, taking a vibrator having two load capacitances as an example of a measuring device having three terminals. Note that the present invention is not limited to the examples,
It will be easily understood by those skilled in the art that the number of measurement terminals and measurement parameters can be appropriately modified and changed.

FIG. 4 is a perspective view of an electronic component measuring jig according to an embodiment of the present invention, and FIG. 5 is an exploded perspective view thereof. As shown in these figures, the electronic component measuring jig 4 of this embodiment
Reference numeral 0 denotes a DUT pressing means 52 for pressing the DUT 51 against the electrode, a DUT pressing means 52, and a DUT pressing means 52 in addition to a main body 42 having a connector group 41 for connection to a measuring instrument (not shown) and wiring.
DUT guide means 53 for positioning 51 at a predetermined position, and an electrode board 54 having electrodes for providing electrical connection to a measuring instrument are provided. DU of the present embodiment
The T pressing means 52 includes a clamp unit 55, a holder 56 fixed thereto, a rod 57 slidably penetrating the holder 56, and a knob 58 for fixing the rod 57 to the holder 56. ing. The holder 56 has a first through-hole provided to penetrate the rod 57 and a second through-hole having a thread, which is provided vertically and communicates with the first through-hole. Have. The knob 58 is provided with a screw thread so as to be screwed into the second through hole. By rotating the rod, the rod 57 can be fixed / released in the holder, and the longitudinal position of the tip of the rod 57 can be freely adjusted and fixed. Position can be adjusted. With such a configuration,
By operating the clamp unit 55, the rod 57
Moves up and down together with the holder 56, and the clamp unit 5
In the lock position 5, the tip of the rod 57 is
Will be pressed down on the upper surface. The adjustment of the pressing force is performed by adjusting the length of the rod 57. The clamp unit 55 functions to switch between fixing / release of the DUT 51 to / from the electrode board 54, and includes a generally known latch mechanism. It should be noted that those skilled in the art know the details of the clamp unit 55, and a detailed description thereof will not be given here. Various forms for obtaining the above-mentioned operation are available for this.

The DUT guide means 53 includes a slide base 5
9, an angle 60, a slide unit 61, and a guide plate 62. Slide unit 6
As shown in the figure, 1 is composed of two members which are slidable up and down, and the lower member 63 is fixed to the main body 42, the upper member 64 is fixed to the slide base 59, and as a result, The base 59 is slidably mounted on the main body 42. In order to improve the sliding performance of the slide base, the slide unit 6
It is also possible to incorporate a ball bearing into 1. The guide plate 62 is fixed to the angle 60, and the angle 60 is fixed to the slide base 59 to be integrated with the slide base. An opening that matches the shape and size of the DUT 51 is provided at the center of the guide plate 62 so that the DUT can move on the electrode board 54 together with the movement of the slide base 59 in a state fitted in the opening. It has become. Therefore,
By moving the slide base 59 in the direction of arrow D in FIG. 4, the position of the DUT on the electrode board can be changed. Incidentally, the angle 60 serves as a handle for facilitating the operation of the slide base 59 by the user, and is not always necessary. In this embodiment, the guide plate 62 is fixed to the slide base 59 via the angle 60,
It is also possible to design to fix directly to the slide base. Further, it is possible to prepare a guide plate having openings of various shapes and sizes according to the type of DUT, and to replace the guide plate corresponding to the guide plate when measuring a different type of DUT.

As shown in FIG. 6, a plurality of electrode groups 65 are provided on the electrode board 54 in a desired number of connection forms. Measurement wirings corresponding to the respective electrode groups are provided on the electrode board. Connected to electrodes. Although not shown, the electrode board can be constituted by a PC board (printed wiring board), and necessary measurement wiring is incorporated therein.
In the case of the present embodiment, it is represented by an equivalent circuit shown in FIG.
It is assumed that an oscillator with a load capacitance is applied as a DUT. This DUT includes one vibrator and two load capacitors. Therefore, as a result, a circuit as shown in FIG. 3 for measuring each of these three elements (Z, C _L , C _R ) must be formed. Each electrode group is formed with a unique wiring to the connector 41 of the main body so as to form each circuit for measuring these elements. More specifically, the measuring instrument H
Electrode pads (not shown) corresponding to i, Lo, and G are formed, and these electrode pads are provided on the surface of the measurement jig when the electrode board 54 is connected to the measurement jig 42. The electrodes are connected to the Lo and G electrodes 68, respectively. In this way, at the position A shown in FIG. 7, the connection configuration of the measurement circuit (a) of FIG. In the connection mode, the DUT is connected to the measuring instrument. Therefore, for each measurement of each element in the DUT, the DUT is positioned, latched, measured, released, and the DU is moved to the next measurement position.
By performing the procedure of moving T, each element in the DUT can be measured.

Further, in order to facilitate positioning of the DUT at the positions A to C, a ball plunger 66 is provided on the guide plate 62 or the slide base 59, and when the DUT comes to a predetermined position on the surface of the main body. A hole 67 can be provided so that the tip of the ball plunger 66 is engaged.

Further, according to the present invention, there is provided an electrode capable of obtaining a large contact surface pressure with a relatively small load. In the present invention, the above-described effect is obtained by making the shape of the electrode into a three-dimensional shape having a curved surface such as a cylindrical shape or a spherical shape. In particular, when the electrode surface is cylindrical or spherical, even if the contact moves on the surface, the curvature does not change and the surface pressure does not change, which is effective in terms of measurement stability. Hereinafter, the surface pressure of the conventional planar electrode and the surface pressure of the cylindrical and spherical electrodes according to the present invention will be compared to explain how the electrode structure of the present invention is superior.

Assume that a load of 3N is applied to the upper surface of the DUT, and a load of 1N is applied to each of three contact surfaces (see FIG. 8). In the case of the conventional flat electrode, if the width of the DUT terminal is 0.4 mm and the depth is 0.8 mm, the contact area S is S = 0.4 × 0.8 = 0.32 mm ² , and the surface at one contact point the pressure P becomes ^{P = 1N / 0.32mm 2 ≒ 3.1N} / mm 2.

On the other hand, when the surface of the electrode is cylindrical, the contact portion is elastically deformed by the application of a load as shown in FIG. 8, and under the same conditions as above, the electrode is made of beryllium copper having a diameter of 0.5 mm. When the calculation is performed by applying the Hertz's formula for the contact of a curved surface, assuming that the DUT is alumina, the surface pressure is maximized at the contact line portion before elastic deformation occurs,

(Equation 1) Becomes Where, E ₁ : Young's modulus of beryllium copper = 11 × 10 ⁴ N / mm ² ν ₁ : Poisson's ratio of beryllium copper = 0.33 E ₂ : Young's modulus of alumina = 34 × 10 ⁴ N / mm ² ν ₂ : Poisson's ratio of alumina = 0.26 q: load applied to the DUT (in this case, 1N).

Further, when the surface of the electrode is spherical with a radius of 0.5 mm,

(Equation 2) Becomes Thus, even if the same load is applied,
The surface pressure at each contact is 110 times larger than that of a flat surface when the electrode surface is cylindrical, and about 60 times when the electrode surface is spherical.
It becomes 0 times.

As one embodiment utilizing the above-described electrode shape according to the present invention, an electrode 91 formed by bending a cylindrical wire into a rectangular shape as shown in FIG. 9 can be considered. As can be easily understood from FIG. 9, the bent sections on both sides penetrate through holes provided in the electrode board 54 and are soldered from the back surface of the electrodes. In addition, a pin-shaped electrode 92 having a hemispherical shape at the tip is penetrated into a through hole provided at a point equidistant from the opposite ends of these two wire-shaped electrodes 91, and similarly soldered. . According to the arrangement of the electrodes, in the case of the DUT having the form shown in FIG. 9, if the center terminal of the DUT is positioned so as to be located at the position of the center pin-shaped electrode, the size of the DUT is within a certain range. Different DUTs can be accommodated. Further, the center electrode does not have to be aligned with the electrodes at both ends, and may be arranged with a slight offset from the row of the electrodes at both ends as shown in the figure. As a result, even for a relatively small DUT, the distance between the center electrode and both end electrodes can be ensured, processing becomes easy, and the DUT can be installed in a well-balanced manner.

In another embodiment, as shown in FIG. 10, all three electrodes can be pin-shaped electrodes (only one electrode group is shown for simplicity). ). Similarly, as shown in FIG.
It is also possible for all of the electrodes to be wire electrodes (similarly, only one electrode group is shown).
The shape of these electrodes can be appropriately selected according to the size and shape of the DUT and the desired surface pressure.

By adopting the electrode configuration according to the present invention described above as the electrode in the above-described embodiment of the electronic component measuring jig, it is possible to easily measure three-terminal components and reduce errors caused by the length of the electrode. In addition, it is possible to realize an electronic component measuring jig that has a remarkably significant effect of significantly improving measurement reproducibility as compared with the conventional one.

[0024]

As described above in detail, according to the present invention, the conventional problem that the contact resistance becomes unstable because the pressure at the contact surface with the DUT cannot be increased is solved. It is possible to realize an electrode for an electronic component measuring jig that can secure a necessary surface pressure without increasing a load to be applied. Also, by using this electrode, the DUT can be exchanged,
An electronic component measuring jig that can easily and accurately measure a plurality of elements in a three-terminal device can be provided. Further, it becomes possible to simultaneously achieve both the exchangeability of the DUT and the improvement of the measurement accuracy and the measurement reproducibility, which could not be achieved by the conventional technology. Furthermore, the conventional problem that the measured value varies due to a slight difference in the DUT mounting position before and after the DUT is replaced is also solved, and the reproducibility of the measurement is drastically improved.

Although the present invention has been described in detail with reference to its most preferred embodiments, it will be appreciated that the embodiments described above can be changed and modified without departing from the spirit of the invention. Therefore, the scope of the present invention is limited only by the content of the appended claims.

[Brief description of the drawings]

FIG. 1 is a view showing a conventional electronic component measuring jig.

FIG. 2 is a diagram illustrating a measurement circuit of a three-terminal device and an equivalent circuit thereof.

FIG. 3 is a diagram illustrating three connection forms of a measurement circuit of a three-terminal device.

FIG. 4 is a perspective view of an electronic component measuring jig according to an embodiment of the present invention.

FIG. 5 is an exploded perspective view of an electronic component measuring jig according to one embodiment of the present invention.

FIG. 6 is a perspective view of an electrode board according to an embodiment of the present invention.

FIG. 7 is a diagram for explaining how a DUT is arranged on the electrode board of FIG. 6;

FIG. 8 is a diagram for explaining the principle of an electrode according to the present invention.

FIG. 9 is a top view and a sectional view of one embodiment of an electrode according to the present invention.

FIG. 10 is a diagram showing one embodiment of an electrode according to the present invention.

FIG. 11 is a view showing one embodiment of an electrode according to the present invention.

FIG. 12 is a perspective view of an embodiment of the electrode shown in FIG. 9;

[Explanation of symbols]

 51: DUT 52: Pressing means 53: DUT guide means 54: Electrode board

Claims (7)

[Claims] 1. A DUT which is fixedly installed on an electronic component measuring jig so as to protrude from a surface of a device under test (DUT) installation.
An electrode for obtaining contact with a terminal of the UT,
The surface area that can be in contact with
The electrode is characterized in that, when a load is applied in a state where it is placed on the surface area, the area in contact with the DUT undergoes elastic deformation. 2. The electrode according to claim 1, wherein said surface region has a cylindrical shape. 3. The electrode according to claim 1, wherein said surface region has a spherical shape. 4. The electrode according to claim 1, comprising a cylindrical wire bent in a rectangular shape, and having a contact area with the DUT in a central section thereof. 5. The electrode according to claim 1, wherein the tip is formed of a pin-shaped member having a spherical shape, and the tip has a contact area with the DUT. 6. An electronic component measuring apparatus, comprising: at least one of the electrodes according to claim 1; and a pressing means for pressing a DUT against the electrode. jig. 7. The two electrodes according to claim 2 or 4 are arranged in a row on a DUT installation surface, and at the point equidistant from opposing ends of these electrodes. Is arranged, and further,
An electronic component measuring jig comprising a pressing means for pressing a DUT placed on these three electrodes against these electrodes.