JPH04264745A - Microwave prober - Google Patents

Abstract

PURPOSE:To permit a microwave prober which can be used for inspecting the electronic conditions of each part of an electronic circuit to easily observe the operating conditions of the electronic circuit from the outside of a package without touching. CONSTITUTION:The prober is provided with a microwave transmitting means which transmits unmodulated microwave to an electronic circuit 30 to be measured and a microwave receiving means which receives modulated microwave which is reflected by the electronic circuit to be measured and modulated in response to the circuit current or voltage of the electronic circuit. A unmodulated microwave is irradiated on the electronic circuit to be measured from the microwave transmitting means, the modulated reflecting wave is received and the wave is inspected. Thus, a voltage corresponding to the circuit current/voltage of the electronic circuit to be measured is received.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave prober that can be used to test the electrical condition of each part of an electronic circuit.

0002

2. Description of the Related Art The operation of electronic circuits is normally checked by observing the voltage/current waveforms of the circuit using an oscilloscope or the like. In this case, the probe of the oscilloscope is brought into contact with the desired point of the circuit. There are electromagnetic (coil-type) and electrostatic (capacitance-type) means for checking the status of a circuit without contact, but they are suitable for checking the status of low-voltage, small-current circuits such as electronic circuits. I have not found any suitable equipment for testing using this method. There is a method that uses an electron beam to inspect the current/voltage status of electronic circuits. That is, an electronic circuit formed on a semiconductor substrate is set in an electron beam device,
The electronic circuit is turned on to be in operation, and the electronic circuit is scanned with an electron beam to obtain reflected electrons and/or secondary electrons, from which the voltage/current state of the electronic circuit can be determined.

0003

[Problems to be Solved by the Invention] In the method of inspecting a required part of an electric circuit by bringing the probe of an oscilloscope into contact with it, the required part is exposed to the outside as an observation terminal.
Unless the cover of the required part can be removed or disassembled to expose it, observation is not possible. For example, in order to observe the operating status of a sealed module with electronic circuits and batteries built into the case, it is necessary to destroy the case, which is not easily possible if the case is filled with resin. Therefore, waveform observation is almost impossible.

[0004] In the method using an electron beam as a probe, it is necessary to insert the electronic circuit into a vacuum apparatus, and inspection cannot be easily performed. It is an object of the present invention to improve the above-mentioned problems and provide a tool that allows the operating status of electronic circuits to be easily observed from outside the package without contact.

[0005]

Means for Solving the Problems As shown in FIG. 1, the microwave prober of the present invention includes means for transmitting unmodulated microwaves to an electronic circuit under test 30, and a means for transmitting unmodulated microwaves to an electronic circuit under test 30.
and means for receiving reflected waves from. In FIG. 1, these microwave transmitting means and microwave receiving means are combined into one microwave transmitting/receiving section 10, but they may be separate. The microwave transmitter/receiver 10 includes a microwave oscillator 12, a microwave detector 14, and a microwave amplifier 16. In FIG. 1, a microwave coupler 18 is further provided, and the antenna 20 is used for both transmission and reception.
If the transmitting means and the receiving means are separate, the microwave coupler 18 is not necessary, and instead two antennas 20 are provided, one for transmitting and one for receiving.

[0006]

[Operation] In this microwave prober, the microwave output from the oscillator 12 is directly transmitted to the coupler 18, without modulation.
It is transmitted to the electronic circuit under test 30 through the antenna 20. This state is shown in FIG. Unmodulated microwave is electronic circuit 3
0 and is reflected by the antenna 20, but this reflected wave is modulated according to the current and voltage state of the input section of the electronic circuit 30.

The modulated microwave received by the antenna 20 enters the detector 14 together with the unmodulated transmitted wave that enters through the coupler 18, where it is detected and the modulated component is extracted. This modulated microwave is amplitude and phase modulated,
Such a modulated wave is difficult to demodulate, but it can be easily demodulated if it is mixed with an unmodulated wave. The output waveform of the wave detector 14 corresponds to the current and voltage state of the input section, and can be measured by inputting it into an oscilloscope, observing it, comparing it with normal conditions, etc. It is possible to perform status checks, normal/abnormal operation tests, etc. Figure 2 shows the procedure for the above test. In the electronic circuit 30 of this figure, 32
, 34 are transistors, and 36 is a microwave strip line.

[0008]

[Example] When unmodulated microwaves are emitted toward an object to be measured and the reflected wave is received, the reflected wave consists of a simple emitted wave and a component that is coupled to the electrical circuit under test and re-emitted. . Vector A in FIG. 2 indicates the above-mentioned unmodulated microwave, and vector B
is the simple reflected wave, C is the re-reflected component, and D is their composite wave received by the antenna. Microwaves coupled into an electrical circuit cause the PN of the transistor in the circuit to
Its amplitude, phase, etc. change depending on changes in parameters such as junction capacitance and collector resistance. C1 indicates the re-emission component whose amplitude and phase have changed, and D1 indicates the composite wave of C1 and B. Since changes in transistor parameters correspond to changes in circuit voltage and current, the re-emission component also changes in response to circuit voltage and current. In this way, a signal corresponding to the circuit current/voltage can be extracted from the microwaves D and D1 returning to the microwave transmitter/receiver.

FIG. 3 shows an embodiment of the microwave prober of the present invention. 10a is the housing of the microwave transmitter/receiver, 10b
is the high frequency input/output connector attached to the housing, 10c
10d is a signal output connector, and 10d is a power supply current (DC) input connector. A microwave oscillator 12, a detector 14, an amplifier 16, and a microwave coupler 18 composed of a strip line are housed inside the housing 10a. A DC return L is connected between the main line of the coupler 18 and the ground. 22 is a coaxial cable, one end is connected to the connector 10b, and the other end is connected to the micro dipole antenna 2.
0 connects. Power is supplied to the microwave transceiver 10 through the connector 10d, and the input end of an oscilloscope (not shown) is connected to the output end of the amplifier 16 through the connector 10c.
The antenna 20 is brought close to the part to be measured of the electronic circuit 30. As mentioned above, by transmitting unmodulated microwaves from this antenna, receiving modulated microwaves from the device under test, and displaying the detected output waveform on an oscilloscope, you can know the voltage/current status of the device under test. .

The appropriate microwave frequency to be used is 1 to 3 GHz, which allows the device to be constructed at low cost and the distributed constant line to be formed relatively compactly. If the detector 14 is connected to the main line side of the coupler 18 as shown, the loss of the received signal can be reduced. It is preferable to use a Schottky barrier diode for the detector 14 so that it can operate from a very small signal. Since the output of the detector is very small, it is amplified by an amplifier 16 to a level that is easy to observe with an oscilloscope.

[0011]

As described above, according to the present invention, voltage and current waveforms of electronic circuits that cannot be touched with an oscilloscope probe can be observed without contact.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a microwave prober of the present invention.

FIG. 2 is an explanatory diagram of the operation of FIG. 1;

FIG. 3 is an explanatory diagram of an embodiment of the present invention.

[Explanation of symbols]

10 Microwave transmitter/receiver section 12 Oscillator 14 Detector 16 Amplifier 18 Coupler 20 Antenna 30 Electronic circuit under test

Claims (3)

[Claims] 1. Microwave transmitting means for transmitting unmodulated microwaves to an electronic circuit under test (30), and a modulated microwave reflected from the electronic circuit under test and modulated according to the circuit current or voltage of the electronic circuit. A microwave prober comprising a microwave receiving means for receiving microwaves, and the microwave receiving means outputs a voltage corresponding to a circuit current or circuit voltage of the electronic circuit to be measured. [Claim 2] Microwave transmitting means and receiving means (
10) includes a microwave oscillator (12) and an antenna (20).
), and a detector (14). 3. The microwave transmitting means and the receiving means include a microwave oscillator, a transmitting/receiving antenna, a microwave coupler (18), and a wave detector, and the antenna, etc. are connected to one end of the main line of the microwave coupler. 2. The microwave prober according to claim 1, further comprising a detector connected to the end thereof and an oscillator connected to the coupled line.