JPH0758166A - High-frequency probe device - Google Patents

Abstract

PURPOSE:To obtain a high-frequency probe device having low losses whereby the transmission of the signal of the wideband extending from DC to the frequency not lower than 100GHz and the application of such a signal to an element to be tested are made possible, by providing respectively in the device an optical inputting terminal, a photoelectric conversion element, an optical signal transmitting medium, a waveform shaping circuit for electric signal, an electric signal outputting terminal, and an electric signal transmitting medium. CONSTITUTION:A high-frequency probe device is used for the estimations of the high-frequency electric characteristics of semiconductor elements and semiconductor integrated elements to be tested. In such high-frequency probe device, an optical signal inputting terminal 11, a photoelectric conversion element 13, an optical signal transmitting medium 12 whereby an optical signal inputted to the optical signal inputting terminal 11 is guided to the photoelectric conversion element 13, a waveform shaping circuit 15 for electric signals whereby the electric signal is matched with the inputting condition of the element to be tested, and an electric signal outputting terminal 17 are provided respectively. Further, first and second electric signal transmitting media 14, 16 are provided respectively in the device. By the first electric signal transmitting medium 14, the electric signal output of the photoelectric conversion element 13 is guided to the waveform shaping circuit 15 for electric signals. By the second electric signal transmitting medium 16, the electric signal output of the waveform shaping circuit 15 for electric signals is guided to the electric signal outputting terminal 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency probe device used for evaluating high-frequency electrical characteristics of test semiconductor elements and semiconductor integrated elements, and particularly to high-frequency characteristics enabling high-frequency characteristic evaluation of high-speed and wide-band semiconductor integrated devices of 100 GHz or more. Regarding a probe device.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor element and a semiconductor integrated element are evaluated for high frequency characteristics in a wafer state or a chip state, a high frequency signal is applied to a signal input terminal on the element and a signal output terminal on the element is applied. A probe called a high frequency probe has been used for detecting the response signal. FIG. 6 is a block diagram showing an embodiment of a high frequency probe device according to the prior art. In FIG. 6, 1
Is an electric signal input terminal, 2 is an electric signal transmission medium, 3 is an electric signal mode conversion means, 4 is an electric signal transmission medium, and 5 is a contactor. When this high-frequency probe device is used to apply a high-frequency signal to the device under test, the coaxial connector or the waveguide is used as the electric signal input terminal 1, and the high-frequency electric signal output from the sine wave generator or pulse generator is coaxial. It is input to the electric signal input terminal 1 via a cable or a waveguide. The electromagnetic wave in the coaxial or waveguide mode is converted into the coaxial or waveguide mode and then applied to the device under test from the electric signal output terminal. That is, the connection between the signal source and the device under test is electrically performed using the electric signal as a transmission medium.

At present, a band up to 100 GHz is realized as a commercial product. However, in the coaxial cable, it is necessary to reduce the distance between the signal center conductor and the grounding outer conductor as the frequency increases, and it is essential to reduce the diameter.However, the loss increases as the diameter decreases, and the connection distance with the measuring device is limited. . Currently, the coaxial structure has a limit of 65 GHz. Waveguides are used in higher frequency bands, but since the waveguide itself is a narrow band due to its structure, for example, 50GHz-75GHz, 75-1
Unless multiple probes with different structures of 10 GHz for each band were used, it was not possible to evaluate the characteristics from the low frequency to the required upper limit frequency.

As a typical high frequency characteristic evaluation method,
(1) Scattering parameter measurement using network analyzer, (2) Time response measurement for impulse waveform using impulse generator and sampling oscilloscope,
(3) An error measurement rate for a pseudo random pattern using a pulse pattern generator and a code error rate measuring device, and (4) eye pattern measurement using a pulse pattern generator and a sampling oscilloscope.

Among these, in (1) scattering parameter measurement, the frequency of a single sine wave is swept to evaluate the loss and reflection characteristics, so it is possible to use different probes for each frequency band. However, in other evaluation methods, the input signal itself contains a wideband frequency component, so in the evaluation using the above probe, a coaxial probe capable of transmitting from DC must be used, and the frequency must be around 65 GHz. The upper limit frequency was restricted.

In the evaluation method (2), the time response measurement for the impulse waveform requires a steepness of the pulse, but the pulse repetition frequency may be as low as about 10 MHz. For this reason, at the research level, the input signal itself uses a 10 MHz pulse with a rise time and a fall time of about 1 ns. For example, as shown in FIG. In this evaluation, a non-linear line is configured to make the pulse waveform asymmetric, or the pulse waveform is made asymmetric by the step recovery diode, and the fall time is greatly shortened to broaden the frequency component of the signal. Had been realized. In FIG. 7, D
Is a diode (capacitance component having bias dependency), and L is a transmission line having a characteristic impedance Z1.

The evaluation methods (3) and (4) are indispensable for evaluating the performance of, for example, a wide band amplifier or a discriminator which constitutes a repeater for optical transmission, but the pulse applied to the device under test has a steep waveform. Both high repetition frequencies are required. For example, in order to measure the bit error rate at a bit rate of 100 Gb / s, a clock frequency of 100 GHz and a rise time and a fall time of about 3 ps are required. The speed performance of semiconductor devices has dramatically improved with the progress of device structure and miniaturization. In the research stage, 40 Gb / s operation logic circuits were already announced, and 100 Gb / s in the near future.
The realization of class action is unquestionable. However, for the above reasons, it is impossible for the conventional probe apparatus to execute the evaluation methods (3) and (4) on these high frequency devices.

Therefore, it is desired to realize an extremely wide-band probe that can propagate all the frequency components contained in the signal source.

[0009]

As described above, it has been difficult for the conventional high-frequency probe device to realize low-loss wideband signal transmission from DC to about 100 GHz and signal application to the device under test.

It is an object of the present invention to solve the conventional problems and to provide a high-frequency probe device capable of transmitting a signal in a wide band from DC to 100 GHz or more and applying a signal to a device under test with low loss.

[0011]

In order to achieve the above object, a high frequency probe device of the present invention comprises an optical signal input terminal,
An opto-electric conversion element, an optical signal transmission medium that guides an optical signal input to the optical signal input terminal to the opto-electric conversion element, an electric signal waveform shaping circuit, an electric signal output terminal, and an opto-electric conversion element A first electric signal transmission medium for guiding an electric signal output to the electric signal waveform shaping circuit; and a second electric signal transmission medium for guiding an electric signal output of the electric signal waveform shaping circuit to the electric signal output terminal. It is a feature. .

[0012]

In the present invention, an optical signal having a repetition frequency and a pulse waveform equivalent to the electrical signal required for evaluation is input, and the optical signal is electrically converted by a broadband photoelectric conversion element arranged at a short distance from the device under test. The signal is converted into a signal, and the obtained electric signal is applied while being matched with the input condition of the device under test. To replace the electrical signal input, which used to be band limited in the past, with an optical signal input, and further to mount the photoelectric conversion element and the electrical signal waveform shaping circuit on the probe device to shorten the electrical signal transmission distance after conversion. Low loss and from direct current
It realizes broadband signal transmission over 100 GHz and signal application to the device under test.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the high frequency probe device according to the present invention. This high frequency probe device includes an optical signal input terminal 11 and an optical signal transmission medium 1.
2, photoelectric conversion element 13, first electric signal transmission medium 1
4, an electric signal waveform shaping circuit 15, a second electric signal transmission medium 16 and a contactor 17.

The optical signal input terminal 11 functions as a terminal for inputting a high-speed optical pulse train signal generated externally. By applying, for example, an optical fiber connector as the optical signal input terminal 11 and connecting the optical pulse signal generation source and the optical fiber connector via the optical fiber, the optical pulse signal can be guided to the high frequency probe device with extremely low loss. Is possible. For example, the loss can be suppressed to about 1 dB over the entire signal band by using a commercially available 1 m single mode optical fiber with a wavelength of 1.55 μm and an FC type connector.

The optical pulse train signal is described in, for example, Reference Document 1 (M.Ji
nno, “Ultrafast Time-Division Demultiplexer Based
on Electrooptic On / Off Gates, ”IEEE Joumal of Lig
htwave Technology, Vol.10, No.10, pp.1458-1465, Oct.19
As described in 92.), it can be generated by the following method. That is, a semiconductor laser beam is modulated into an optical pulse train by an electro-optic amplitude modulator such as LiNbO ₃ , and then the modulated light is demultiplexed and the phase difference between them is adjusted by the waveguide length, and then combined to obtain an extremely high bit rate. It is possible to obtain a rate optical pulse signal. For example, a 20 Gb / s electro-optic amplitude modulator has already been put into practical use, and using this, an optical pulse signal of 20 Gb / s is first generated, and then an optical pulse signal of 80 Gb / s is obtained by further multiplexing 4. It is possible.

The optical pulse signal input from the optical signal input terminal 11 is transmitted through the optical signal transmission medium 12 to the optoelectric conversion element 1.
3 is guided to the light receiving surface. As the optical signal transmission medium 12, for example, an optical waveguide such as an optical fiber can be applied.

When the light receiving area of the photoelectric conversion element 13 is narrower than the spot size of the signal light emitted from the end face of the optical fiber or the optical waveguide, for example, one configuration of the high frequency probe device of the present invention shown in FIG. As shown in the block diagram showing one embodiment of the optical signal transmission medium 12 as an element,
By configuring the optical signal transmission medium 12 with the optical waveguide 18 and the light converging means 19, and providing the condensing means 19 at the final stage of the optical waveguide 18, the coupling efficiency of the optical signal transmission medium 12 and the photoelectric conversion element 13 can be improved. Deterioration can be suppressed. An optical fiber, for example, is used as the optical waveguide 18, and a so-called front spherical fiber in which the end face of the optical fiber is processed into a spherical shape, a front spherical converging type rod lens, or a converging type rod lens and a spherical lens is used as the converging means 19. A configuration such as a combination of can be applied.

The photoelectric conversion element 13 converts an incident optical signal into an electric signal, and is a pin photodiode, a Schottky photodiode, an avalanche photodiode, an MSM (metal-semiconductor-metal) photodiode, or the like. Can be applied. GaAs Schottky photodiodes, pin photodiodes, MSM photodiodes, etc. have achieved a wide band of 70 GHz to 100 GHz. By applying these broadband photodiodes to photoelectric conversion elements, extremely high speeds of 100 Gb / s or more can be achieved. It is possible to obtain the electric signal of

The first electric signal transmission medium 14 guides the electric signal output from the photoelectric conversion element 13 to the electric signal waveform shaping circuit 15, and the second electric signal transmission medium 16 outputs the electric signal waveform shaping circuit 15. The signal is guided to the contactor 17. These first and second electric signal transmission media 14, 1
6 can be formed as an impedance matching line such as a coplanar waveguide or a microstrip line on a dielectric substrate such as alumina or sapphire. The frequency characteristics of the electric signal transmission media 14 and 16 are determined by the line structure, the line material, and the dielectric material. For example, gold and alumina having low loss are used as the line material and the dielectric material, respectively, and the line width is 100 μm and the line thickness is 0. When a 50 Ω coplanar line with 5 μm is formed, the loss at 100 GHz or less is 0.2 d.
It can be suppressed to about B / mm. As will be described later, even if the electric signal waveform shaping circuit 15 has the largest scale, it can be realized by an integrated circuit of several mm square or less, so that the distance from the photoelectric conversion element 13 to the contact 17 can be suppressed to about 10 mm. Therefore, the electric signal transmission medium 14, 1
In No. 6, it is possible to secure a signal band (3 dB) of about 100 GHz.

The electric signal waveform shaping circuit 15 matches the electric signal obtained by the opto-electric conversion element 13 with the input condition of the device under test. Specifically, it is a voltage level shift circuit or a voltage transition speed adjustment. It is configured by a circuit, a voltage amplitude adjusting circuit, or a circuit combining two or more thereof.

FIG. 3 shows an embodiment in which the electric signal waveform shaping circuit 15 which is one component of the present invention is configured as a voltage level shift circuit. The voltage level shift circuit 20 is composed of a capacitor C inserted in series in the signal line, an inductance L1 branched to the output end of the capacitor C, and an inductance L2 branched to the input end of the capacitor C.
Since the DC component of the electric signal is removed by the capacitance C,
By applying a DC voltage to the other end A of the inductance L1, the output level of the electric signal can be DC-shifted by the applied voltage. If the input signal condition of the device under test is the SCFL (source coupled FET logic) level used in a GaAs logic IC, for example, it is necessary to set the intermediate level of the signal to -0.4V, and to the terminal A at -0.4V.
Should be applied. The inductance L2 applies a DC level to the output signal itself of the photoelectric conversion element 13, and when a photodiode is applied to the photoelectric conversion element 13, for example, the bias voltage of the photodiode should be adjusted via the inductance L2. Therefore, the output signal can be level-shifted by the required DC component while keeping the operating conditions of the photodiode optimum. In the figure, E is a ground terminal, IN is a signal input terminal, and OUT
Is a signal output terminal.

When the electric signal waveform shaping circuit 15 is configured as a voltage transition speed adjusting circuit, for example, a step recovery diode or a reference 2 (MJWRodwell, M. Kamegawa,
R. Yu, M. Case, E. Carman, and KSGiboney, “GaAs Nonli
near Transmission Lines for Picosecond Pulse Genera
tion and Millimeter-Wave Sampling, ”IEEE Transacti
ons on Microwave Theory and Techniques, Vol.39, No.
The nonlinear transmission line described in 7, pp.1194-1204, July, 1991.) can be applied. Document 2 describes that "these response speeds have asymmetry between rising and falling, and an asymmetric pulse waveform can be shaped symmetrically." This is the "non-linear transmission line". The response speed of the photodiode is determined by the time required for carriers to be induced by light irradiation and further drift to reach the electrode, and the time required for the generated carriers to disappear due to light blocking. The latter generally requires more time. That is, the waveform converted into an electric signal often has asymmetric rise time and fall time. This asymmetry of the waveform is determined by the response characteristics of the photodiode applied as the photoelectric conversion element, so if the asymmetry of the waveform is a problem,
It is useful to apply this voltage transition speed adjustment circuit.

The electric signal waveform shaping circuit 15 may be composed of a voltage amplitude adjusting circuit, and for example, an optical band amplifying circuit can be applied. When a photodiode is used as the photoelectric conversion element 13, the obtained output signal amplitude has an upper limit due to the conversion efficiency and output saturation characteristics of the photodiode. For example, output saturation current is 2mA and conversion efficiency is 30
When a 0 mW / A photodiode is applied, even if an optical signal of 10 mW is incident on a system with a characteristic impedance of 50Ω
Only 100 mV voltage can be obtained. This voltage amplitude adjusting circuit is useful when amplifying such a small signal amplitude to a logical amplitude (for example, 800 mV in the above-mentioned SCFL).

Furthermore, the electric signal waveform shaping circuit 15 may be configured by combining two or more functions such as a voltage level shift circuit, a voltage transition speed adjusting circuit, and a voltage amplitude adjusting circuit. It suffices if it fulfills the function of matching the electric signal waveform obtained by the element 13 with the input condition of the element under test.

When the circuit area in the case where the electric signal waveform shaping circuit 15 is configured as described above is estimated, the semiconductor integrated circuit technology is applied to the largest wide band amplifier circuit to realize a chip area of several mm square. it can. Further, even when the voltage level shift circuit shown in FIG. 3 is configured by an individual circuit portion, by using a microchip capacitor for the capacitance C and a ribbon inductor for the inductances L1 and L2, the capacitor C is mounted on an area of several mm square. can do. Therefore, since the electric signal waveform shaping circuit 15 as a whole can be accommodated in an area of about 10 mm square at most, this circuit is mounted on the dielectric substrate described in the embodiments of the electric signal transmission media 14 and 16 and It is possible to connect and integrate with the signal transmission line. FIG. 4 shows an embodiment of an integrated configuration of the electric signal transmission media 14 and 16 and the electric signal waveform shaping circuit 15. The first and second coplanar waveguides 23 and 24 are respectively formed on the single dielectric substrate 21.
The second electric signal transmission mediums 14 and 16 are formed, and the electric signal waveform shaping circuit 15 is mounted between them. The signal terminals of the coplanar waveguides 23 and 24 and the signal terminals such as ground and power on the dielectric substrate 21 are connected to the corresponding signal terminals of the electric signal waveform shaping circuit 15 via the solder bumps 22, respectively. ing. With this, 10m
The photoelectric conversion element 13 and the contactor 17 can be connected with each other with a short transmission distance of about m, and an ultrahigh frequency component around 100 GHz can be guided to the element under test with a small loss.

The contactor 17 is a signal output terminal of the high-frequency probe device and has a function of applying an electric signal to the signal input terminal of the device under test. It is no different from the contact of the conventional high-frequency probe device. The pad arrangement of the device under test, that is, the signal terminal arrangement, often has a configuration in which both sides of the normal signal input terminal are sandwiched by ground terminals due to high frequency characteristics. For example, the electric signal transmission media 14 and 16 are coplanar waveguides. In the case of forming by (3), as shown in the embodiment shown in FIG. 4, a total of three contacts 17 for signals and for two grounds sandwiching them may be formed corresponding to the pad arrangement of the device under test.

FIG. 5A is a bottom view showing an embodiment of the high-frequency probe device according to the present invention, and FIG.
Also shows a side view. An optical fiber connector 25 is applied as the optical signal input terminal 11, and an optical fiber is applied as the optical signal transmission medium. The tip of the optical fiber 26 is connected to the probe housing 29 via the ferrule 27 and the guide 28.
It is fixed to. An optical lens 30 for condensing is fixed to the probe housing 29 via a lens guide 31. A photodiode 32 as the photoelectric conversion element 13.
Is applied to the probe housing 29 so that the incident surface of the photodiode 32 faces the optical fiber emitting surface. The electric signal output of the photodiode 32 is connected to a first coplanar waveguide 34 formed as the electric signal transmission medium 14 on the dielectric substrate 33. The electric signal waveform shaping circuit 15 is mounted on the dielectric substrate 33, and the output end of the first coplanar waveguide 34 is guided to the input terminal of the electric signal waveform shaping circuit 15. The output end of the electric signal waveform shaping circuit 15 is connected to the second coplanar waveguide 35, and is transmitted to the contact 17 formed at the tip of the second coplanar waveguide 35. As is apparent from the figure, the optical signal input can eliminate the frequency band limiting factor at the electrical signal input terminal, which is inevitable in the conventional electrical signal input. Further, the photoelectric conversion element 13 and the electric signal waveform shaping circuit 15 are mounted on the probe, and the electric signal transmission distance between the element to be tested and the element under test can be significantly shortened as compared with the conventional configuration, and therefore the high frequency loss is reduced. be able to.

[0029]

As is clear from the above description, according to the present invention, there is provided a high-frequency probe device capable of low-loss wideband signal transmission from DC to 100 GHz or more and application of a signal to a device under test. be able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a high frequency probe device according to the present invention.

FIG. 2 is a block configuration diagram showing an example of an optical transmission medium that is a component of the high-frequency probe device according to the present invention.

FIG. 3 is a circuit diagram showing an embodiment in the case where an electric signal waveform shaping circuit which is one component of the high frequency probe device of the present invention is configured as a voltage level shift circuit.

FIG. 4 shows an exemplary implementation of an electric signal transmission medium and an electric signal waveform shaping circuit, which are components of the high-frequency probe device according to the present invention. This figure is a view as seen from the surface on which the electric signal waveform shaping circuit is mounted, and shows through through each signal connection point between the electric signal waveform shaping circuit and the dielectric substrate.

5A is a bottom view showing an embodiment of the high-frequency probe device according to the present invention, and FIG. 5B is a side view of the same.

FIG. 6 is a block diagram showing an embodiment of a high-frequency probe device according to the related art.

FIG. 7 is a circuit diagram showing an embodiment of a non-linear line which is a component of a high-frequency probe device according to the prior art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electrical signal input terminal, 2 ... Electrical signal transmission medium, 3 ... Electrical signal mode conversion means, 4 ... Electrical signal transmission medium, 5 ... Contact motor, 11 ... Optical signal input terminal, 12 ... Optical signal transmission medium, 13 ... photoelectric conversion element, 14 ... first electric signal transmission medium, 15 ... electric signal waveform shaping circuit, 16 ... second electric signal transmission medium, 17 ... contactor, 18 ... optical waveguide, 19
... light condensing means, 20 ... voltage level shift circuit, 21 ... dielectric substrate, 22 ... solder bump, 23 ... first coplanar waveguide, 24 ... second coplanar waveguide, 25 ... optical fiber connector, 26 ... Optical fiber, 27 ... Ferrule, 28 ... Guide, 29 ... Probe housing, 30 ... Optical lens, 31 ... Lens guide, 32 ... Photodiode,
33 ... Dielectric substrate, 34 ... First coplanar waveguide,
35 ... Second coplanar waveguide.

Claims (1)

[Claims] 1. A high-frequency probe device used for evaluating high-frequency electrical characteristics of a test semiconductor device and a semiconductor integrated device, comprising: an optical signal input terminal, an opto-electrical conversion element, and an optical signal input to the optical signal input terminal. An optical signal transmission medium for guiding to an electrical conversion element, an electrical signal waveform shaping circuit for matching an electrical signal with an input condition of a device under test, an electrical signal output terminal, and an electrical signal output of the photoelectric conversion element. A high frequency wave comprising a first electric signal transmission medium for guiding the electric signal waveform shaping circuit to a shaping circuit and a second electric signal transmission medium for guiding an electric signal output of the electric signal waveform shaping circuit to the electric signal output terminal. Probe device.