JPH01193654A - voltage measurement probe - Google Patents

Abstract

PURPOSE:To achieve a higher accuracy, by forming a transparent electrode on the entire one side of an electrooptic crystal and a metal electrode having a contact pin on the other side thereof being divided one-or two-dimensionally with respect to a measuring point of an object to be measured. CONSTITUTION:The title probe 10 is provided with a transparent electrode 12 on one side of an electrooptic crystal plate 11 and a metal electrode 13 having a contact pin 14 being splitted on the other side thereof separately. Then, a laser light from a laser light source 20 is made incident into the probe 10 with the direction of polarization thereof changed by a 1/4 wavelength plate 16 through an optical system. Then, the laser light is transmitted through the electrode 12 and the crystal plate 11 and reflected with an electrode 13a to be incident into a detector 21. Then, a voltage at a portion 6a of an object 6 to be measured is applied between the electrode 12 and the electrode 13a and the refractive index of the laser light changes within the crystal plate 11 thereby enabling detection of a voltage from a variation of the laser light incident into the detector 21.

Description

[Detailed Description of the Invention] [Summary] Regarding a voltage measurement probe of a voltage measurement device using an electro-optic crystal, the purpose of improving measurement accuracy is to irradiate the electro-optic crystal with a light beam to measure the measurement point of the object to be measured. The voltage measuring probe of the voltage measuring device that measures the voltage in the electro-optic crystal plate has a transparent electrode on one side and a metal electrode with contact pins on the other side corresponding to the measurement point of the object to be measured. It is constructed by dividing it into one or two dimensions.

[Industrial application field]

The present invention relates to a voltage measuring device for measuring voltage distribution in semiconductor devices and the like, and particularly to a voltage measuring probe with improved measurement accuracy.

[Conventional technology]

When reading the detailed voltage distribution of parts with complex circuit configurations, such as the surface of semiconductors and SI elements,
Conventionally, methods have generally been used, such as measuring by moving an electrical measuring probe little by little, or pressing a large number of contact pins against a desired area and measuring while switching channels.

FIG. 3 is an explanatory diagram showing an example of a conventional voltage measurement method, and shows a measurement state in the -dimensional direction.

In the figure, 1 is the object to be measured + la is its power supply part, 2 is the voltage measurement device, 3 is the test control system + 3a is the signal cable that transmits the test signal to the voltage measurement part.

3b is a signal cable that transmits a clock signal etc. to the voltage measuring device; 4 is a measurement cable that transmits the signal from the connector 5 to the voltage measuring device 2; and 4a is a measurement cable that transmits the signal waveform from the measuring probe 5a to the voltage measuring device 2. It's a cable.

In the figure, with the test signal, clock signal, etc. sent from the test control system 3 to the respective required devices, the power feeding part 1a of the object to be measured 1 is contacted with the tip of the measuring probe 5a while sequentially shifting, and each contact area is The voltage distribution of the object to be measured 1 is measured by calculating the signal waveform obtained in the voltage measuring device 2.

The conventional voltage measurement method with such a configuration has the advantage that the control system, measuring device, etc. can be installed at a location away from the object to be measured 1, but on the other hand, it Since the voltage is measured at a remote location via the measurement cables 4 and 4a to the voltage measurement device 2, the impedance of the measurement cable may cause an error in the voltage measurement value, and the frequency of the voltage waveform of the power supply part 1a may When the voltage is on the order of 2 1 z, the distributed inductance and distributed capacitance of the measuring cable 40 affect the voltage to be measured, causing distortion in the voltage waveform and making it impossible to measure the voltage accurately.

[Problem that the invention seeks to solve]

Conventional voltage measurement methods have the problem that the impedance of the measurement cable causes errors in the voltage measurement.
In addition, G11 has a particularly high frequency of the voltage waveform of the object to be measured.
In the case of z-order, there is a problem in that the distributed inductance and distributed capacitance of the measurement cable 4 impede accurate voltage measurement.

[Means for solving problems]

The above problem is that the voltage measurement probe of the voltage measurement device, which measures the voltage at the measurement point of the object to be measured by irradiating the electro-optic crystal with a light beam, has a transparent electrode on one side of the electro-optic crystal plate, and a transparent electrode on the entire surface of one side of the electro-optic crystal plate. This problem can be solved by a voltage measuring probe formed by dividing a metal electrode with a contact bottle into one-dimensional or two-dimensional parts corresponding to the measurement points of the object to be measured.

[For production]

- When a voltage is applied partially to M through an electrode through an electro-optic crystal plate made of bismuth silicon oxide (BSO) or bismuth germanium oxide (BGO), the polarizability is increased only in the vicinity of the voltage applied part in the crystal. changes, and the refractive index in the direction of the electric field changes.

Therefore, by measuring the change in the refractive index as a change in the light intensity of transmitted light, it is possible to find out the voltage value of the portion to which the voltage is applied.

That is, a light-reflective metal electrode electrically connected to a voltage measurement point of the object to be measured is formed on the surface of the electro-optic crystal plate facing the object to be measured, and a transparent electrode is formed on the other surface.

In this state, when a focused light beam is irradiated from the transparent electrode side, the light beam passes through the transparent electrode and is reflected on the back surface of the metal electrode, but while traveling back and forth within the crystal, the light beam is applied to the metal electrode. The polarization range is changed due to the anisotropy of the refractive index change caused by the applied voltage. Therefore, the voltage at the measurement point of the object to be measured can be determined by detecting the reflected light as the strength or weakness of the afterlight that is reflected by the polarized beam splinter.

The present invention provides a voltage measurement probe based on such a voltage measurement method directly on an electro-optic crystal plate, and in particular, since the electro-optic crystal plate is used in a vertical type in which the direction of light passage and the direction of voltage application are the same, the electro-optic The thickness of the crystal plate can be made sufficiently thin. Therefore, highly accurate voltage measurement is possible without generating errors in voltage measurement values due to transmission impedance or distortion of voltage waveforms due to distributed capacitance.

Furthermore, each measurement area is made independent of the electrode on the side of the object to be measured:
By forming a voltage crosstalk between the regions, stable voltage measurement becomes possible.

〔Example〕

FIG. 1 is a diagram showing an example of the voltage measurement probe according to the present invention, in which (A) is a schematic configuration diagram of the main part of the voltage measurement device, and (B) is a diagram illustrating details of the voltage measurement probe. . Further, FIG. 2 is a diagram showing another embodiment of the voltage measurement probe.

In FIG. 1(A), the broken line indicates the present invention in which a transparent electrode 12 is formed on the entire surface of one side of the electro-optic crystal plate 110, and a metal electrode 13 with contact pins 14 is formed on the other surface in a divided state. The voltage measurement probe 10 is electrically connected to a plurality of measurement points of the object to be measured 6 indicated by the dashed line and the corresponding metal electrodes (strains) via the contact pins 14 mentioned above.

16 is a 174 wavelength plate for changing the polarization direction of light;
17 is a polarizing beam splitter that transmits only specific polarized light and reflects other polarized light, 18 is a lens system, and 19 is a polarizing beam splitter that transmits only specific polarized light and reflects other polarized light.
, an x-Y deflector for scanning in the Y direction,
20 is a laser light source, 21 is the voltage measurement probe 10 mentioned above.
Each of the detection detectors has an arithmetic function of receiving reflected light from the detector and converting it into a voltage value.

The figure shows the state when measuring the voltage at a portion 6a of the object to be measured 6, and the voltage at the portion 6a is applied to the metal electrode 13a of the voltage measurement probe 10 corresponding to the portion 68. .

The laser light emitted from the laser light source 20 and traveling in the A direction is
-Y deflector 19. Lens system 18. The light passes through the polarizing beam splitter 17, has its polarization direction changed by the 1/4 length plate 16, and enters the voltage measuring probe 10. Furthermore, the laser beam passes through a transparent electrode 12 and an electro-optic crystal plate 11 and reaches a metal electrode 13.
It is reflected in the direction a and travels in the opposite direction, and the polarization direction is further changed by the I/4 wavelength plate 16 and is reflected without passing through the polarization beam splitter 17 UifA and travels in the direction B and enters the detection detector 21.

At this time, since the voltage of the part 6a of the object to be measured 6 is applied between the transparent electrode 12 of the electro-optic crystal plate 11 and the metal Ti 113a, the refractive index for the laser beam changes within the crystal plate 11. However, the intensity of the laser light incident on the detection detector 21 changes. Therefore, the voltage at the portion 6a is detected from the amount of change.

Note that when measuring a portion other than the portion 6a of the object to be measured 6, the xy deflector 19 is operated to deflect the beam direction of the laser beam to a required position.

Therefore, by repeating this operation, the measurement areas of the electro-optic crystal plate 11 corresponding to the plurality of measurement points of the object to be measured 6 are sequentially scanned, and the voltage distribution of the object to be measured 6 is detected and measured. There is.

Figure (B) is a perspective view showing details of the voltage measurement probe 10, and shows a state in which metal electrodes are arranged two-dimensionally.

In the figure, the transparent electrode 12 formed on the entire surface of one side of the electro-optic crystal plate 11 made of bismuth silicon oxide (BSO) or bismuth germanium oxide (BGO) with a thickness of about 100 μmm is made of indium tin oxide alloy (ITO). The metal electrode 13 formed on the other side is usually made of gold (Au) to increase the reflection efficiency of the laser beam on the back side. ), etc. are vapor-deposited to the same thickness as the transparent electrode 12 and masked so that each measurement area is independently masked to a size of approximately bnm square for each measurement area.

Further, the contact pin 14 for electrically connecting each measurement point of the object to be measured 6 has a thickness of 100 to 200 μm.
A gold (Au) wire with a length of less than 1 mm is fixed in the vertical direction by brazing or the like.

Figure 2 shows an example of a pond that aims to prevent crosstalk between measurement areas in an electro-optic crystal plate, and shows a thin layer in the electro-optic crystal plate part between metal electrodes. It is a product formed from a product.

In the figure, 11 is an electro-optic crystal plate as in FIG. 1(B).

12 is a transparent electrode, 13 is a metal electrode, and 14 is a contact pin.

Further, on the surface of the electro-optic crystal plate 11 between the metal electrodes 13,
Both width and depth are about 20 to 30 μmm? 1 flla is formed using a precision cutter such as a Guising tool.

In this case, the electric field between the transparent 1m12 and the metal Jilaa is, for example, 13a adjacent to the metal electric field Fi13a.
b or 13c, and therefore crosstalk between measurement areas can be prevented.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a voltage measurement probe that can stably perform highly accurate voltage measurements and can follow and measure even when the voltage waveform of the object to be measured is high speed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a voltage measurement probe according to the present invention, FIG. 2 is a diagram showing another embodiment of the voltage measurement probe, and FIG. 3 is an explanatory diagram showing an example of a conventional voltage measurement method. It is. In the figure, 6 is an object to be measured, 10 is a voltage measurement probe, 11 is an electro-optic crystal plate, lla is a groove, '12 is a transparent electrode, 13 is a metal electrode, 13a, 13b,
13c is metal TL pole, 14 is contact I pin, 16
is a 174 wavelength plate, 17 is a polarizing beam splinter, 18 is a lens system, 19 is an X-Y deflector, 20
21 represents a laser light source, and 21 represents a detection detector. (A) (B) ” (Hag month (Nitro voltage J shell, Shi L))
Figure 1. Figure 1. Layer force Eta law, b-fr, and other actual E examples Σ.
Diagram of the conventional 0 voltage clear mep-9 urine and water diagram
figure

Claims (1)

[Claims] A voltage measurement probe of a voltage measurement device that measures the voltage at a measurement point of an object to be measured by irradiating an electro-optic crystal with a light beam comprises a transparent electrode on one entire surface of an electro-optic crystal plate; A voltage measurement probe characterized in that the other surface is formed by dividing a metal electrode with contact pins into one or two dimensions corresponding to the measurement points of the object to be measured.