JPH0720620Y2 - Test fixture calibration fixture - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention generally relates to a test fixture such as a tweezers type for measuring impedance of a device under test,
In particular, the present invention relates to a calibration jig for predicting the impedance component of itself and performing calibration on the measuring instrument side.

[Conventional technology and its problems]

Conventionally, when measuring the impedance of a device under test such as a chip capacitor, for example, a test fixture of tweezers type is provided and a known measuring method such as four terminal pair is used. Furthermore, the impedance components (L, C, R) of the test fixture itself cause an error in the impedance measurement of the device under test.
The calibration was performed by the method described below.

FIG. 3 shows a tweezers type test fixture 30.
In order to calibrate the impedance component of the test fixture 30 as described above, the test fixture 30 is brought into an open state and a short state to perform calibration. First, the contact portions 31, 31 'of the test fixture 30 that come into contact with the device under test (not shown) are directly contacted,
The resistance component R and the inductance component L of the test fixture 30 are measured in the short-circuited state (hereinafter referred to as short-circuit calibration). Next, the contact portions 31, 31 'are separated from each other, and the capacitance component C of the test fixture 30 is measured in the open state (hereinafter, referred to as open calibration). The impedance component of the test fixture 30 is corrected by arithmetically processing these measured values from the impedance measurement result of the device under test by a known method.

However, in these calibrations, the dimensions of the actual device under test vary, and the length is 1.6 to 1
Since it may reach a range of 0.0 mm, it was not suitable for different dimensions of the device under test. That is, when the length d of the device under test changes to d + Δd, the impedance component of the test fixture 30 is also changed from L to L.
It has been impossible to calibrate the impedance variation ΔL, ΔC of the test fixture 30 corresponding to the length variation Δd of the device under test by changing from + ΔL, C to C + ΔC. In addition, when impedance measurement is performed at a high frequency such as 15 MHz, the inductance variation ΔL and the capacitance variation ΔC of the test fixture 30 described above become serious error factors. For example, when the impedance of the device under test of 1,000 pF at a frequency of 10 MHz is measured by the test fixture 30 having the inductance of 16 nH (L = 16 nH), the impedance value Z of the device under test would normally be
It should be 15Ω, but in reality, the test fixture
Due to the inductance of 30, the impedance value of the device under test is 16Ω, which causes an apparent error of 6% or more in comparison with the true impedance value Z. This means that when the impedance of the device under test is low as described above, the inductance component of the test fixture is high, and when the impedance of the device is high, the capacitance component C of the test fixture adversely affects the impedance measurement.

[Effect of device]

Therefore, an object of the present invention is to provide a test fixture calibration jig that can easily calibrate the impedance component of the test fixture that changes depending on the length of the device under test, which is the above-mentioned problem. .

[Outline of device]

One embodiment of a calibration fixture for a test fixture according to the present invention is a means for calibrating a tapered inductance made of a conductive material such as metal having a width within the dimension range of a device under test and the inductance. And a means for calibrating a capacitance made of an insulating material such as plastic having the same configuration as that of the means. Using this jig, a position having the same width as the length of the element to be measured on the inductance calibration means is held between the contact portion pair of a test fixture such as a tweezers type, and short calibration is performed. Further, an open calibration is carried out by holding a position of the guard part pair of the test fixture so that the contact part pair on the capacitance calibrating means is separated by the length of the device under test.

[Example of device]

A preferred embodiment according to the present invention is shown in FIG. Hereinafter, the present invention will be described in detail with reference to this drawing. Calibration jig 10 is the third
It has an inductance calibration member 11 for calibrating the inductance component of the test fixture as shown in the figure, in particular, the inductance component that changes depending on the length of various devices under test. It is made of a conductive material such as metal and has a size range of the device under test, for example, 1.6 m.
It is formed in a taper shape having a width of m to 10.0 mm.
Further, the following correction can be easily performed with a desired length by providing a scale on the surface of the inductance calibrating member 11 in a portion having a width corresponding to the dimension of the device under test. Therefore, the inductance component corresponding to the dimension of the device under test is preliminarily measured by holding the position on the inductance calibration member 11 having the same width as the length of the device under test with the contact portions 31, 31 'of the test fixture 30. be able to. That is, the inductance component of the test fixture can be calibrated. Further, the calibration jig 10 also has a capacitance calibration member 12 in order to calibrate the capacitance component of the test fixture that changes depending on the dimensions of the device under test. Capacity calibration member
The reference numeral 12 is made of an insulating material such as plastic, has a width within the dimensional range of the device under test similarly to the inductance calibration member 11, and is formed in a tapered shape. The capacitance calibration member 12 is held by the guard parts 32, 32 'of the test fixture, the contact parts 31, 31' are opened at the same distance as the length of the device under test, and the capacitance component of the test fixture is measured. can do. There may be a difference in the width between the test fixture guard portion and the contact portion. For example, as shown in FIG. 3, since the width between the guard portions 32 and 32 'is wider than the width between the contact portions 31 and 31', the width of the capacitance calibration member 12 is larger than that of the inductance calibration member 11 by that amount. It is made to be wide. In this way, it is possible to calibrate the capacitance component of the test fixture that changes depending on the dimensions of the device under test.

FIG. 2 shows another embodiment of the present invention. Reference numeral 21 is a jig for calibrating the inductance component of the test fixture 30, which is made of the same material as the inductance calibrating member 11 of FIG. The calibration jig 21 has various dimension widths of the device under test and is formed in a step shape. FIG. 2 also shows the operation of measuring the inductance component of the test fixture 30 of FIG. As shown in the figure, a step having the same width as the length of the device under test is attached to the contact part of the test fixture.
Hold 31 and 31 ', and measure the inductance component of the test fixture 30 in the short state. Although not shown, the calibration jig for calibrating the capacitance component of the test fixture is also made of the same material as the capacitance calibrating member 12 of FIG. 1, and can be configured in a step shape like the calibration jig 21. . Again, test fixture 30
In the guard part 32, 32 ', the contact part 31, 31' holds a step having a width in which the contact part 31, 31 'is in the open state by the same distance as the length of the device under test, and the capacitance component of the test fixture 30 is measured in the open state. .

In addition, it is apparent from the above description that these calibration means may be integrated or may be separately manufactured.

Further, the capacity correction may be like a ruler with a scale. In other words, by applying the connection part of the test fixture to this scale and separating them by a desired distance, the connection part is opened with the same length as the dimension of the device under test, and open calibration is performed. It is also possible.

Instead of the above-described embodiment, for example, a conductive member or an insulating member having the same shape as the elements to be measured having various sizes can be used. Then, these plural members are used as a calibration jig for a set of test fixtures.

[Effect of device]

As described above, the test fixture calibration jig according to the present invention has a simple configuration, and can easily calibrate the impedance component of the test fixture that changes depending on the dimensions of the device under test. It enables more accurate measurement.

[Brief description of drawings]

FIG. 1 is a schematic view of a calibration jig for a test fixture which is an embodiment of the present invention. FIG. 2 is a view for explaining a calibration operation using a calibration jig for a test fixture which is another embodiment of the present invention. FIG. 3 is a schematic diagram of a tweezers type test fixture. 10,21: Calibration jig, 11: Inductance calibration member, 12: Capacitance calibration member, 30: Test fixture, 31,31 ': Contact part, 32,32': Guard part, 33: Cable.

Claims (6)

[Scope of utility model registration request] 1. A test fixture calibration jig for preliminarily measuring the impedance of a test fixture used for measuring the impedance of a device under test, and calibrating the impedance measurement. When calibrating the inductance component of the impedance of the test fixture, which has a plurality of widths equal to the dimensions of the various measured elements to be sandwiched, it is made of a conductor and the capacitance component of the impedance of the test fixture. When calibrating
A test fixture calibration jig for calibrating the capacitance component and the inductance component of the test fixture, which is made of an insulator and changes depending on the dimensions of the device under test. 2. The test fixture calibration jig according to claim 1, wherein the width of the test fixture calibration jig is tapered. 3. A test fixture calibration jig, wherein the width of the test fixture calibration jig according to claim 1 is a step. 4. A conductor portion having a plurality of widths for calibrating the inductance component of the test fixture, and a capacitance component of the test fixture having the same shape as the conductor portion. The jig for calibrating a test fixture according to claim 1, characterized in that an insulator portion having a plurality of widths is integrally formed. 5. The test fixture calibration jig according to claim 4, wherein the width of the conductor portion and the width of the insulator portion are formed in a tapered shape. Chua's calibration jig. 6. The test fixture calibration jig according to claim 4, wherein the width of the conductor portion and the width of the insulator portion are stepwise. Chua's calibration jig.