JP3469160B2 - Contact inspection sensitivity improvement device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a technique in the field of measurement and testing of minute electronic components. More specifically, for example, a device for improving the sensitivity of a high resistance electronic component measuring instrument such as Hewlett-Packard's 4349B [trademark], as well as a small “minimum” of the measurable range using such a measuring instrument. The present invention relates to a method for improving the sensitivity of a measuring instrument when making a "presence or absence of a component" decision.

[0002]

2. Description of the Related Art In the technical field of minute ceramic capacitor chips, the external dimensions are extremely small and the capacitance is 1
It is a well-known fact that there are some picofarads and below, and there is a limited parallel conductance that is some kind of direct current leakage from such parts.
Since the capacitor chip is an essential electronic component for the operation of computers and many other electronic devices, it is important to measure such a DC leakage current and classify the chips according to the degree of leakage. Conventionally, a high resistance electronic measuring instrument such as the above-mentioned Hewlett-Packard Company 4349B [trademark] is used.

In the ceramic capacitor industry, a high-speed measuring device "handler" for measuring DC leakage current from the ceramic capacitor is connected to a Hewlett-Packard 4349B (trademark) measuring device which operates at high speed. When the handler receives the untested capacitor chips, one by one or by one group is placed on the test stand to connect the terminals of the capacitors to the tester, and the direct current leakage is tested (one with the limited current source and the other with the limited current source). Connect to Hewlett-Packard's 4349B [trademark] (hereinafter "HP4349B") and other similar high resistance / low current measuring instruments. Before or after the test, a measuring instrument is used to verify that the presence of the capacitors on the test bench is well connected across the test circuit.
Performs a test or "contact inspection" of the "presence or absence of parts". The reason for performing such pre- and post-tests is to confirm that the components on the test bench are sufficiently connected to the test circuit. Otherwise, parts with large leakage characteristics may be erroneously classified as “good”.

In the case of HP4349B, the device whose triaxial cable is tested with the measuring instrument (hereinafter simply referred to as "device")
"LO" side (low potential side. Below is the low side
Sometimes called)) . The inner conductor of this cable sends a direct current signal from the device, and the outer shield of the cable is grounded to test the "presence of parts" HP
The internal shield generated in the 4349B sends a high-frequency guard signal of about 0.5 MHz.

Devices that are directly connected to the power supply have a "high"
(HI) ”side (high potential side; hereinafter also referred to as high side
Sometimes there are high frequencies (for high frequency components)
It is grounded. During the "parts present" test, the HP4349B applies the same amplitude as the high frequency signal that moves the guard applies to the inner conductor of the triaxial cable. When the connection with the ceramic capacitor, the existence of which is to be confirmed, is not sufficient, the high-frequency current flowing through the guard (the outer end of which is open) becomes equal to the current flowing through the inner conductor, so that the presence of components cannot be detected. On the contrary, when the connection with the parts on the test bench is reliable, the signals are not equal,
Parts with sufficient connections will be recognized by the HP4349B. The "absent" classification is required to retest any parts that may have been on the test bench and is given a higher priority than the classification as a result of normal leakage current testing.

[0006]

The drawback of the above-mentioned prior art is that even if the connection on the test stand is sufficient, it is 2 pF.
It means that parts with the following capacitance values often go undetected.

The present invention has been made in consideration of such problems, and it is determined whether or not there is a component on the HP4349B that can be placed on the test stand with sufficient electrical connection, even if the component is 0.75p.
The present invention provides a device capable of determining even a weak electrostatic capacitance value of F and a measuring method using the device.

[0008]

In order to solve the aforementioned problems, the device and method according to the present invention are set forth in the claims.
Adopt the configuration as described .

That is, according to the invention of claim 1 , the electronic component
Perform test procedure to apply DC power from DC power supply to
Before you test the above electronic parts on the test bench,
It is a tester for testing,
And the means for detecting the alternating current flowing through the electronic components.
The above tester
In a device that enhances the sensitivity of the tester: a) Contact the above tester
A signal booster connected to the input end, the output end,
Multiple boosting of AC signal received at the input terminal above 1
Boot means for supplying a boosted AC signal to the output terminal
B) said tester having said signal booster with
Connect the signal output end of the signal booster and the input end of the signal booster;
c) Connect the output end of the signal booster to the DC power source and the upper side.
Connected between the test stands and applied by the above tester.
In addition to the AC signal
All AC signals applied to the above-mentioned electronic parts
I am trying to increase the amplitude.

In the second aspect, the signal booster is a transformer.

In claim 3, the signal booster is an amplifier.

In the present invention, the turn ratio of the primary winding: secondary winding of the transformer of the signal booster is about 1.25 to about 2.25.
And

According to the invention of claim 5 , the multilayer ceramic
Apply DC power from the DC power supply to the chip capacitor
Before performing the test procedure, place the above multilayer ceramic on the test bench.
High resistance to test for chip chip capacitors
A tester that applies an AC signal to the electronic components
Means and flow through the above multilayer ceramic chip capacitors
Used with those having means for detecting alternating current
The device that enhances the sensitivity of the high resistance tester
: A) A signal booster connected to the above tester.
The input terminal, the output terminal, and the AC signal received at the input terminal.
The signal is boosted by a factor greater than 1 and the boosted AC signal is output.
Said signal booster having a boot means for supplying to the power end
B) the signal output end of the tester and the signal boot
The input end of the star; c) the output end of the signal booster
Is connected between the DC power supply and the test stand, and
In addition to the AC signal applied by the tester,
To the above multilayer ceramic chip capacitor
Applied to the above multilayer ceramic chip capacitors
The amplitude of all AC signals is increased.

In claim 6, the signal booster is a transformer.

In claim 7, the signal booster is an amplifier.

In claim 8, the signal booster is about 1.
A transformer having a turns ratio of primary winding: secondary winding of 25 to about 2.25 was used.

According to the invention of claim 9 , leakage of electronic parts
Directly connect the above electronic components from a DC power source to measure current.
Before applying the test procedure to apply the
A tester that tests for the presence of the above electronic components.
Then, an AC signal is applied to the electronic component,
Used with those that detect alternating current flowing through
In the method of increasing the sensitivity of the tester: a) the above test
The AC signal output from the
Supply to the power end; b) boost from the output end of the signal booster
The extracted AC signal; c) output of the signal booster
The boosted AC signal from the power end is applied to the DC power supply and
Connect between the above test stands and apply with the above tester
In addition to the AC signal that is
All AC signals applied to child parts and applied to the above electronic parts
I am trying to increase the amplitude of.

According to a tenth aspect of the present invention, the method according to the ninth aspect is characterized in that the boosted signal is at least three times the protocol test signal.

In claim 11, the signal booster is a transformer, and the step of transmitting the signal via the input of the signal booster comprises transmitting the signal via the primary winding of the transformer. 10. The method of claim 9, wherein the step of picking up the boosted signal from the output of the signal booster comprises the step of picking up the boosted signal from the secondary winding of the transformer.

In claim 12, the signal booster is an amplifier, and the step of transmitting the signal via an input of the signal booster includes transmitting the signal via an input of the amplifier, the output of the signal booster 10. The method of claim 9, wherein the step of picking up the boosted signal comprises the step of picking up the boosted signal from the output of the amplifier.

[0021]

The device of the present invention is a "signal booster" including a transformer, an amplifier, or an element equivalent to a differential input driven from an internal guard shield of an HP4349B input triaxial cable and an external guard shield. ing. The output of this element is in series with the output from the high voltage limited power supply and is the phase added to the high frequency guard voltage applied to the device under test, which comes directly from the HP4349B, but Increase the amplitude of
And the sensitivity of the "existence of parts" inspection circuit in HP4349B is HP434.
Improving the internal structure of 9B without any modification.

More specifically, the present invention relates, in part, to performance enhancements that increase the sensitivity of a tester's secondary or tertiary tests. When the secondary or tertiary test is to check the existence of electronic components on the test bench, or when it is performed by double high frequency signals passing through the electronic components to be tested, the primary reason for the tester is The functional function is to test the key parameters of electronic components (resistance, capacitance, conductance, etc.). In this case, "sufficient contact" is a contact with a low resistance value that does not impair the sensitivity of the primary test and other various functions of the tester.

Therefore, a first object of the present invention is to provide means for determining whether or not there is a device (electronic component) on a test table before conducting a high resistance current leakage test. In addition, a test circuit that conducts a current leakage test by using this means is related to ceramic chip capacitors .
And closed (contact failure with the capacitor
The circuit is not open due to the absence of), this
The result is to provide a way to ensure that whatever value is recorded is that of the capacitor on the test bench. Furthermore, by providing a device that expands the opportunity to use the tester to test the next capacitor by shortening the time required for the start of the test and the test itself, and also shortening the operation time, it leads to high quality. To save the production cost of the ceramic chip capacitor, to provide a device for increasing the handling amount of the ceramic chip capacitor, to improve the performance of the capacitor tester to provide a device for reducing the production cost of the ceramic chip capacitor itself, It is an object of the present invention to provide a device that enhances the performance of a ceramic capacitor tester for inspecting the presence or absence of a capacitor having a capacitance of 0.2 pF or less to save the cost for testing.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an apparatus and a method according to the present invention will be described below with reference to FIGS.

FIG. 1 shows a typical inspection system for determining the leakage value of a ceramic chip capacitor. Although the present invention describes a ceramic chip capacitor here, as long as there is a DUT [Device Under Test] (device under test, hereinafter simply referred to as "device"), whether or not the device is in sufficient electrical contact. It will be understood by those skilled in the art that it can be applied in any case as long as an electrical check is required.

As for HP-4349B [a product of Hewlett-Packard Company], this tester has four identical input channels for earth leakage measurements. Here, for simplicity of explanation, only one of the channels is shown and described. Therefore, it should be understood that the present invention can be similarly applied to all four channels.

In FIG. 1, a high resistance measuring device 1 of HP-4349B
Includes a toroidal transformer 3 having a primary winding 5, a secondary winding 7, and a secondary winding 9, a direct current measuring unit 13, and a high frequency measuring unit 15, and inputs to the large resistance measuring unit 1. Is connected to the input circuit of the HP-4349B via the block capacitor 17. The high frequency generator acting on the toroidal transformer 3 via the primary winding 5 during the "presence of parts" test is not shown here. There is also one that connects a signal to the high frequency measuring unit 15 for phase demodulation, but this is also not shown.

The secondary windings 7 and 9 are constructed by winding a coaxial cable several times, and because of this configuration, the outputs from both are exactly the same. The right sides of these secondary windings 7, 9 are respectively connected to the inner conductor 19 and the effective inner protective shield 21 of the first triaxial cable 25. The left sides of the secondary windings 7 and 9 are connected to the ground and the high frequency measuring unit 15 via a block capacitor 17, respectively. Since the amplitudes of the signals from the secondary windings 7 and 9 are the same and the outer end of the inner protective shield 21 has a low capacitance of grounding, the amplitude of the signal input to the high frequency measuring unit 15 is the outer end. It can be considered to be directly proportional to the ground capacitance of the effective inner conductor 19 in.

The effective inner conductor 19 is connected to the low side of the test stand 27 from the high resistance measuring instrument 1 of HP-4349B. The high side of the test stand 27 is usually 0-5 via line 29.
It is connected to a high voltage power supply 31 in the 00 volt range. The ground shield 33 of the first triaxial cable 25 is also connected to the high voltage power supply 31.

The right side of the test stand 27, that is, the line 29
Is a relatively low impedance with respect to the ground due to the capacitance of the characteristic output impedance of the high-side conductors, lines 29 and 33, and the high-voltage power supply 31, and is represented as the capacitor 37 in FIGS. It is therefore assumed that the ground capacitance of the effective inner conductor 19 at its outer end is approximately equal to the ground stray capacitance of the test stand 27 (and figuratively indicated by the capacitor 39) plus the actual capacitance of the device. You can

During the startup correction cycle of the HP-4349B, the test table 27 is empty, but the digitally converted output of the high resistance measuring instrument 1 obtained there is stored in the memory. During the subsequent presence / absence test of the part, the part is assumed to be located on the test stand 27 so that it can be evaluated that it is present and is in good contact with the test stand 27. Value is subtracted from the digital conversion value. However, one limitation of this method is that during the correction cycle, if the value of stray capacitance 39 is high compared to the value of test bench 27, for example 1 pF, the former value will increase the latter value. It means that when the device value is very low after masking, even if there is a device or chip, it becomes unresponsive to it.

During the leakage test, the programmed high voltage output is applied from the high voltage power supply 31 to the right side of the device on the test stand 27, and the amplified DC leakage current is applied to the input of the DC current measuring unit 13 Winding 9 and first 3
It will flow via the effective inner conductor 19 with the axial cable 25.

The present invention relates to a circuit added to the outside of the HP-4349B as shown in FIG. A second triaxial cable 41 is attached to which the effective inner protective shield 2
Input 4 of booster 45 shown as a transformer via 1
It is connected to the first triaxial cable 25 by a known T-type adapter (not shown) for transmitting to the 3 (primary winding). The secondary winding 51 of the transformer 49 is connected between the output of the high voltage power supply 31 and the high side of the test stand 27. High frequency oscillator in HP-4349B has commonality, so one booster
Sufficient for all four channels of the HP-4349B, which can accommodate four test benches. There is no need to make any minor changes to the internal circuitry of the HP-4349B.

Thus, when the HP-4349B (measuring instrument 1) performs a test protocol, or "contact check", the primary winding 43 of the transformer 49 also requires 500 KHz. The turns ratio of the primary winding 43 to the secondary winding 51 of the transformer 49 may be about 1: 2.5 to about 1: 3, preferably about 1: 3, and the transformer 49 The secondary voltage coming from it is preferably in antiphase with that of the first transformer 3.
The secondary winding 51 is inserted in series with the DC power supply voltage from the high voltage power supply 31 and is applied to the “high” side of the device with a large amplitude of at least three times or more than in the usual case, and is on the test table 27. It is connected to the "virtual" ground in the circuit of Figure 1 when there is no device to power. Thus, a voltage of 500 KHz is applied to the secondary winding 51 of the transformer 49 in series with the chip of the test stand 27, which is about three times the voltage applied to the secondary winding 9 of the first transformer 3. Becomes These two voltages are additional (see
The secondary voltage coming from the voltage transformer 49 is opposite to that of the first transformer 3.
The test table 27 has different phases and the applying direction is different.
The voltage connected in series with the device will be about four times greater than that applied with the conventional circuit of FIG. As described above, according to the present invention, the sensitivity of a large resistance measuring device such as HP-4349B to the capacitance value of the device is improved by about four times.

Of course, the booster 45 may be an amplifier instead of the transformer as shown. It is also obvious that any combination of voltage value, amperage and signal booster is within the scope of the invention.

[0036]

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a circuit called “contact inspection” or “presence or absence of parts” using a Hewlett-Packard (HP) 4349B tester.

FIG. 2 is a conceptual diagram of a preferred embodiment of the present invention in which the circuit of FIG. 1 is improved.

[Explanation of symbols]

25 3-axis cable 31 High-voltage power supply 37 Capacitor 41 3-axis cable 43 Primary winding 45 booster 49 transformer 51 Secondary winding

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-87858 (JP, A) JP-A-11-142449 (JP, A) Actual Kaihei 3-30876 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) G01R 27/02 G01R 27/26 G01R 31/00

Claims (12)

(57) [Claims] 1. A DC power source for a DC power source is printed on an electronic component.
Before performing the applicable test procedure, place the electronic
A tester that tests whether there is an item
A means for applying a signal to the electronic component and the electronic component
With a means for detecting a flowing alternating current
Used in equipment that enhances the sensitivity of the above tester
A ) a signal booster connected to the tester,
The AC signal received at the input end, the output end, and the input end
A multiple of more than 1 and the boosted AC signal is applied to the output terminal
The signal booster having a boot means for supplying
And, b) of the tester signal output terminal and the signal booster ON
Connecting the power end, and c) connecting the output end of the signal booster to the DC power source and the upper side.
Connected between the test stands and applied by the above tester.
In addition to the AC signal
All AC signals applied to the above-mentioned electronic parts
The above-mentioned test, which is at least characterized by increasing the amplitude.
A device that increases the sensitivity of the star. 2. The device according to claim 1, wherein the signal booster is a transformer. 3. The apparatus of claim 1, wherein the signal booster is an amplifier. 4. The signal booster comprises about 1.25 to about 2.
The device according to claim 1, wherein the transformer has a turns ratio of 25 primary windings: secondary windings. 5. A direct current for a multilayer ceramic chip capacitor
Before performing the test procedure to apply DC power from the power source,
The above-mentioned multilayer ceramic chip capacitor is placed on the test stand.
High resistance tester to test whether or not AC
Means for applying a signal to the electronic component, and the multilayer ceramic
Means for detecting alternating current flowing through a chip capacitor
And a high resistance tester as described above
A device for increasing the sensitivity of a) , a) a signal booster connected to the tester,
The AC signal received at the input end, the output end, and the input end
Upper SL output a large fold boosted AC signal boosted from 1
The signal booster having a boot means for supplying
And, b) of the tester signal output terminal and the signal booster ON
Connecting the power end, and c) connecting the output end of the signal booster to the DC power source and the upper side.
Connected between the test stands and applied by the above tester.
In addition to the AC signal
Apply to a ceramic chip capacitor and
The amplitude of all AC signals applied to the
At least characterized by increasing
A device that increases the sensitivity of the star. 6. The device according to claim 5, wherein the signal booster is a transformer. 7. The apparatus according to claim 5, wherein the signal booster is an amplifier. 8. The signal booster comprises about 1.25 to about 2.
Device according to claim 5, characterized in that it is a transformer with a turns ratio of 25 primary windings: secondary windings. 9. The method for measuring leakage current of electronic parts
Test for applying DC power from DC power supply to electronic components
Before performing the procedure, make sure that the above electronic components are on the test bench.
It is a tester for testing whether the AC signal is
Apply to child parts and detect AC current flowing through the above electronic parts
It is used together with the tester to increase the sensitivity of the above tester.
A ) a signal that captures the AC signal output from the tester
Supply to the input end of the booster, b) AC signal boosted from the output end of the signal booster
Was removed, c) an AC described above boosted from the output terminal of the signal booster
Connect the signal between the DC power supply and the test stand,
In addition to the AC signal applied by the tester,
Applying a compressed AC signal to the electronic components,
It is possible to reduce the amplitude of all AC signals applied to the product.
A method to increase the sensitivity of the above tester, which is a feature that is not necessary. 10. The method of claim 9, wherein the boosted signal is at least three times the protocol test signal. 11. The signal booster is a transformer, and the step of transmitting the signal via an input of the signal booster comprises transmitting the signal via a primary winding of the transformer, the signal booster comprising: 10. The step of picking up a boosted signal from the output comprises the step of picking up a boosted signal from the secondary winding of the transformer.
The method described in. 12. The signal booster is an amplifier, and the step of transmitting the signal via an input of the signal booster comprises transmitting the signal via an input of the amplifier.
10. The method of claim 9, wherein picking up a boosted signal from the output of the signal booster comprises picking up a boosted signal from the output of the amplifier.