JP2000241444A - High frequency probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain contact with signal electrodes more securely and stably when a device to be measured has no ground electrode on its surface or when signal electrodes are arranged by a narrow pitch. SOLUTION: When a signal transmission route 23 of a film-like tip end board 21 having a micro strip structure is pressed on a signal electrode 31 of a device 30 to be measured which is placed on a device stage 40 of a ground electrode tip part 20 to obtain electric conduction, while a plate spring 24 screwed to a body block 11 presses the tip end board 21 from a mat ground surface 22 to a signal electrode 31, a ground block 25 holding the tip end board 21 is pressed against a device stage 40 in the pressing direction of the signal electrode 31 to obtain electric conduction. The ground block is connected to the mat ground surface by a part where the tip end board 21 is held, and encloses the signal transmission route, the tip end board 21 may have a plurality of signal transmission routes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for pressing the tip of a signal transmission path against a signal electrode of a device to be measured which is electrically connected to a ground electrode of the device to be measured and which is arranged on a device stage functioning as a ground electrode. Regarding a high-frequency probe connected to an external measuring instrument by a connector connected to the other end of the signal transmission path, particularly, in a device under test, when there is no ground electrode on the surface, and when signal electrodes are arranged at a narrow pitch, The present invention relates to a high-frequency probe capable of more reliably and stably obtaining contact with a signal electrode and electrical characteristics.

[0002]

2. Description of the Related Art Conventionally, this kind of high-frequency probe is shown in FIG.
As shown in the figure, the high-frequency probe 1000 includes a main body block 1010, a tip 1020, and a connector 10
The distal end portion 1020 that contacts the signal electrode of the device under test by the coaxial line portion 1011 penetrating the inside of the main body block 1010 is electrically connected to the connector 1030 connected to the external measuring instrument. I have.

[0003] Further, as shown in FIG.
Reference numeral 20 denotes a signal conductor 10 which is a member having elasticity.
21 and two ground conductors 1022, and these conductors have a coplanar structure in which the ground conductors 1022 are arranged in parallel on substantially the same plane perpendicular to the direction in which the signal conductor 1021 is bent by elasticity, with the signal conductor 1021 at the center. Has formed.

In such an arrangement of conductors, the device under test is limited to a coplanar type device in which signal electrodes and ground electrodes are arranged at the same interval and on the same plane as the conductor at the tip of the high-frequency probe. You.

However, in such a device in which the ground electrodes are arranged on both sides of one signal electrode on the same plane, the surface area becomes large. In particular, gallium arsenide (GaAs)
Since compound devices such as s) have a higher wafer cost than silicon, the number of devices obtained from one wafer is reduced and the cost is increased. Therefore, in a mass-produced device, the ground electrode is not provided on the same plane as the signal electrode, the chip area is reduced, the thickness of the wafer is reduced, and the back surface is used as the ground electrode surface to reduce costs and secure high-frequency characteristics. Is being planned.

In the above-described conventional high-frequency probe, when measuring a device having such a structure, the device to be measured is first mounted on a substrate, and the device is provided on this substrate and has an interval corresponding to the conductor arrangement of the high-frequency probe. Alternatives have been taken, such as connecting to measuring electrodes.

[0007]

The above-described high-frequency probe has the following problems.

The first problem is that when the device to be measured has a structure other than the coplanar structure, it is necessary to prepare a substrate for measurement, and the measurement takes time and effort.

The reason is that, in the above-described high-frequency probe, the signal conductor and the ground conductor that come into contact with the signal electrode of the device under test have a coplanar structure.
This is because a device to be measured other than the coplanar structure requires a measurement substrate for measurement, and the device to be measured needs to be attached to and detached from the measurement substrate. Particularly, in the case of a device having a structure in which a large number of signal electrodes are arranged at a narrow pitch, this wiring operation requires a great deal of time and labor.

The second problem is that when the device under test is pressed against the signal electrode, a sufficient contact pressure cannot be obtained, and the measurement of electrical characteristics is unstable.

The reason is that, in the above-described high-frequency probe, the signal conductor and the ground conductor that are in contact with the signal electrode of the device under test have a structure that bends in free space. Therefore, when the pressing force is increased to perform stable measurement, This is because there is a risk of damaging the conductor at the distal end, so that the pressing force is adjusted.

A third problem is that the area of the device to be measured increases and the product cost increases.

The reason is that in order to measure a device under test with the above-described high-frequency probe, the same positional relationship between the signal conductor and the ground conductor in the high-frequency probe is required to be on the same plane on both sides of the signal electrode in the device under test. This is because it is necessary to dispose a ground electrode in the area.
That is, since the surface area of the device to be measured increases, the number of devices that can be obtained from one wafer decreases. In particular, this problem is remarkable in the case of a compound device such as gallium arsenide which is more expensive than silicon.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to improve the contact with the signal electrodes and the electrical characteristics of the device under test when there are no ground electrodes on the surface and when the signal electrodes are arranged at a narrow pitch. Another object of the present invention is to provide a high-frequency probe that can be obtained more reliably and stably.

[0015]

SUMMARY OF THE INVENTION A high frequency probe according to the present invention provides a signal transmission path to a signal electrode of a device under test arranged on a device stage which is electrically connected to a ground electrode of the device under test and functions as a ground electrode. In the high-frequency probe connected to the external measuring instrument by the connector connected to the other end of the signal transmission path, the tip pressed against the signal electrode of the device under test is pressed against the surface in contact with the signal electrode. A film-shaped tip substrate having a signal transmission path, a leaf spring at a position to press the tip substrate when the tip of the signal transmission path is pressed against the signal electrode of the device under test, and a tip of the signal transmission path. When pressed against the signal electrode of the device under test, it is located between this signal transmission path and the device stage and contacts the And a ground block to obtain conduction.

With such a configuration, even for a device under test having only a signal electrode disposed on its surface, measurement can be performed by electrically connecting the ground electrode of the device to be measured on the device stage surface. It becomes possible. Further, since the leaf spring presses the signal conductor together with the tip substrate against the signal electrode of the device under test, a stable pressing force can be obtained without damaging the thin film-shaped tip substrate and the signal conductor. Therefore, stable measurement can be performed.

Further, as a specific means, the signal transmission path has a microstrip structure in which a microstrip line is formed on the surface of the tip substrate having the back surface as a solid ground surface. The distal end of the signal transmission path to be pressed has a conductor projection that contacts the signal electrode, and the ground block has a shape surrounding the signal transmission path together with the solid ground surface of the distal end substrate. With such a structure, stable measurement of electrical characteristics, particularly at high frequencies, can be realized.

Further, the tip substrate may include a plurality of signal transmission paths corresponding to the plurality of signal electrodes on a surface pressed against the signal electrodes of the device under test. The ground block has a shape surrounding the signal transmission path together with the solid ground surface of the tip substrate. Therefore, it is possible to measure the signal electrodes arranged at a narrow pitch by a configuration including a plurality of signal transmission paths, and further, by a configuration including a partition wall between each of the plurality of signal transmission paths, Since crosstalk between transmission lines can be reduced, accurate high-frequency measurement is possible.

[0019]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a partial cross-sectional side view showing an embodiment of the distal end portion of the high-frequency probe according to the present invention, and FIG. 2 is a perspective view for explaining the structure and operation of the distal end portion 20 of FIG.

First, the outline of the structure of the tip of the high-frequency probe according to the present invention will be described with reference to FIGS.

The tip 20 of the illustrated high frequency probe
Is composed of a tip substrate 21, a leaf spring 24, and a ground block 25. Device under test 30
Has a signal electrode 31 on the front surface in a microstrip structure, while the ground electrode 32 on the back surface provides electrical continuity with the surface of the device stage 40.

The tip substrate 21 is formed of a thin film made of, for example, a polyimide resin having a small dielectric constant, and is made of a material which can bend in the direction perpendicular to the film surface. The tip substrate 21 has a microstrip structure in which a signal transmission path 23 is arranged on the surface in contact with the signal electrode 31 and a solid ground surface 22 is arranged on the back surface.

Even when the tip substrate 21 bends, the signal transmission path 23 and the solid ground plane 22 can be maintained at equal intervals, so that the characteristic impedance does not fluctuate. Also,
One end of the signal transmission path 23 is pressed against the signal electrode 31 of the device under test 30 arranged on the surface of the device stage 40, and the other end is connected to the signal line of the relay board 12 that passes through the main body block 11. Is electrically connected to Therefore, the electrical conduction of the signal reaches the connector connected to the external measuring instrument via the relay board 12.

On the other hand, the leaf spring 24 has a plane whose bending direction matches the bending direction of the tip substrate 21, one end of which is fixed to the main body block 11 with screws 13, and the other tip of which is the tip substrate 21. The signal transmission path 23 is pressed against the signal electrode 31 with a predetermined pressing force by pressing the front end of the signal transmission path 23 against the vicinity of the front end of the solid ground surface 22 which is one surface of the signal transmission path 21.

The tip substrate 21 and the ground block 25 are both connected to the main body block 11 and the relay substrate 1.
It is fixed to 2. At this time, both the solid ground surface 22 and the signal transmission path 23 provided on both surfaces of the tip substrate 21 are fixed, and the solid ground surface 22 is electrically connected to the ground block 25 and is connected to the ground line of the relay substrate 12. Has obtained electrical continuity.

The signal transmission line 23 is fixed inside the ground block 25 with a certain gap, and is electrically connected to the signal lines of the relay board 12.

Accordingly, when the tip of the signal transmission path 23 is pressed against the signal electrode 31 of the device 30 to be measured on the surface of the device stage 40 and electrical conduction is obtained, the tip of the signal transmission path 23 is brought into contact with the surface of the device stage 40. It is pressed upward to obtain electrical contact with the ground electrode 32 and is connected to the solid ground surface 22 which is the ground pattern of the tip substrate 21 at the shortest distance, and to the external measuring instrument via the ground pattern of the relay substrate 12 and the connector. Connected.

Next, the operation and functions will be described with reference to FIG.

First, when the signal transmission path 23 of the tip substrate 21 is pressed against the signal electrode 31 of the device under test 30, the tip substrate 21 bends. The bent tip substrate 21 is pressed by a leaf spring 24 and a constant contact pressure is applied to the signal electrode 31.

At this time, the ground block 25
Is pressed onto the surface of the device stage 40 that comes into contact with the ground electrode 32 of the device under test 30. Therefore, the solid ground plane 22 is
As a result, electrical contact is obtained at the shortest distance with the device stage 40 that is in contact with the ground electrode 32 of the device under test 30, and even if the thin film-shaped tip substrate 21 bends, the solid ground surface 22 and the signal Transmission line 23
At the same time, there is no variation in the characteristic impedance in the transmission path of the high-frequency probe.

[0032]

Next, another embodiment different from the invention described with reference to FIG. 2 will be described with reference to FIG.

FIG. 3 is different from FIG. 2 in that the signal transmission path 23 provided at the distal end portion 20 of the above-described high-frequency probe is brought into contact with the signal electrode 31 of the device under test 30 by a conductive material such as metal. That is, the projection 26 is provided. Due to the contact protrusions 26, electrical conduction to the signal electrodes 31 is further ensured.

Next, with reference to FIG. 4, an embodiment having a plurality of signal transmission lines different from FIGS. 2 and 3 will be described.

FIG. 4 differs from FIG. 2 in that three signal transmission paths 231 are arranged in parallel to one surface of the end substrate 211. Therefore, the front substrate 211 and the ground block 251 surrounding the front substrate 211 have a wider structure in the flow direction of the plurality of signal transmission paths 23 than the front substrate 21 shown in FIG. The leaf spring 24 corresponding to the wide end substrate 211
1 may likewise have a wide width. With such a structure, the device under test 30 having the ground electrode 321 on the back surface and the many signal electrodes 31 with a narrow pitch on the front surface
1 can be placed on the device stage 40 at the ground potential and measured.

Next, a structure in which a plurality of signal transmission paths 231 are provided and a ground wall is formed around the tip substrate 211 will be described with reference to FIGS. With this structure, high-frequency characteristics can be measured more accurately and stably. Here, the case of a plurality of signal transmission lines is shown and described, but the same structure is provided for the case of one signal transmission line already described with reference to the drawings.

FIG. 5 is a plan view showing only the tip portion 201 in FIG.

FIG. 6 is a cross-sectional view taken along the line CC of FIG. 5, and the thin film-shaped tip substrate 211 (not shown in FIG. 5) is, as described with reference to FIG. Are provided with three signal transmission paths 231 and have a solid ground plane 221 on the surface. This tip substrate 211
Has a U-shaped cross section and a gutter-shaped ground block 251, with the signal transmission path 231 inside, to form a lid for an inner space portion. With this structure, the signal transmission path 231
Is a solid ground plane 221 and a ground block 251 except for the foremost part that contacts the signal electrode of the device under test.
And are enclosed with a certain gap. Therefore, the manufacturing cost can be kept low because the structure is simple.

Next, an embodiment different from FIG. 6 will be described with reference to FIG.

FIG. 7 differs from FIG. 6 in the ground block 252. That is, the illustrated ground block 252 additionally forms a ground wall at a gap between the signal transmission paths 231 in order to electromagnetically isolate the signal transmission paths 231 arranged in parallel. With this structure, it is possible to reduce crosstalk noise between the signal transmission lines formed by the signal transmission lines 231.

[0041]

As described above, according to the present invention, the following effects can be obtained.

The first effect is that measurement time and labor can be reduced when measuring a device to be measured having a microstrip structure.

The reason is that the signal conductor and the ground conductor at the tip of the high-frequency probe according to the present invention are arranged in the vertical direction with the direction pressed by the signal electrode of the device under test as the vertical direction, and the microstrip structure is used. This is because it can directly contact the measuring device.

The second effect is that a reliable electric contact with the signal electrode can be obtained.

The reason is that the tip of the elastic leaf spring presses the tip substrate in contact with the signal electrode near the tip of the tip substrate by a predetermined contact pressure.

The third effect is that it can cope with a case where a large number of signal electrodes of the device under test are arranged at a narrow pitch.

The reason is that a plurality of signal transmission paths corresponding to a plurality of signal electrodes in such a device under test can be arranged on the tip substrate.

The fourth effect is that the product cost of the device under test can be reduced.

The reason is that the device area can be reduced by making the electrode structure of the device under test a microstrip structure.

The fifth effect is that when a signal electrode and a power supply electrode of a device under test are mixed and juxtaposed, both signal measurement and power supply can be performed simultaneously by one probe. In particular, even when a plurality of power supply electrodes are juxtaposed, it can be used for power supply.

The reason is that a plurality of signal transmission lines corresponding to a plurality of signal electrodes and a power supply electrode of the device under test can be arranged on the tip substrate, so that a wide operating frequency band and low signal crosstalk between the signal transmission lines cause This is because the influence on the device to be measured when the tip of the signal transmission path of the tip substrate comes into contact can be minimized.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing one embodiment of the present invention.

FIG. 2 is a perspective view illustrating a structure and an operation function of a distal end portion in FIG.

FIG. 3 is a perspective view showing one embodiment at a tip portion different from FIG. 2;

FIG. 4 is a perspective view illustrating a structure of a distal end portion when a plurality of signal paths are provided in FIG.

FIG. 5 is a plan view of the distal end shown in FIG. 4;

FIG. 6 is a cross-sectional view showing one embodiment along the line CC in FIG. 5;

FIG. 7 is a sectional view showing an embodiment having a structure different from that of FIG. 6;

FIG. 8 is a plan view and a side view showing an example of a conventional high-frequency probe.

FIG. 9 is a functional block diagram illustrating an example of a distal end portion in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Main body block 12 Relay board 20, 201 Tip part 21, 211 Tip board 22, 221 Solid ground surface 23, 231 Signal transmission path 24, 241 Leaf spring 25, 251, 252 Ground block 26 Contact protrusion 30, 301 Device under measurement 31 Signal electrode 40 Device stage

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirofumi Inoue 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Koji Matsunaga 5-7-1 Shiba, Minato-ku, Tokyo Japan Inside Electric Company (72) Inventor Masahiko Nikaido 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation Inside (72) Inventor Yuichi Yamagishi 5-27, Minamiazabu 5-chome, Minato-ku, Tokyo Anritsu shares In-house (72) Inventor Satoshi Hayakawa 5-10-27 Minamiazabu, Minato-ku, Tokyo F-term in Anritsu Corporation (reference) 2G003 AE03 AG03 AG05 AG12 AH09 2G011 AA13 AA15 AA21 AB09 AC32 4M106 AA02 AA07 BA09 BA14 DJ33 DJ40

Claims (6)

[Claims] An end of a signal transmission path is pressed against a signal electrode of a device to be measured disposed on a device stage which is electrically connected to a ground electrode of the device to be measured and functions as a ground electrode. In a high-frequency probe connected to an external measuring instrument by a connector connected to the other end, a film-shaped tip substrate having the signal transmission path on a surface in contact with a signal electrode of the device under test,
When the tip of the signal transmission path is pressed against the signal electrode of the device under test, the leaf spring is at a position to press the tip substrate, and the tip of the signal transmission path is pressed against the signal electrode of the device under test. A high-frequency probe, comprising: a ground block that is located between the signal transmission path and the device stage when the device stage is in contact with the device stage to obtain electrical continuity. 2. The high-frequency probe according to claim 1, further comprising: a contact protrusion made of a conductive material that comes into contact with said signal electrode at a tip of a signal transmission path pressed against a signal electrode of a device under test. probe. 3. The high-frequency probe according to claim 1, wherein the signal transmission path forms a microstrip line on the surface of the tip substrate whose back surface is a solid ground surface. 4. The high-frequency probe according to claim 3, wherein the ground block has electrical continuity with the solid ground surface of the tip substrate and surrounds the signal transmission path with the solid ground surface with a predetermined gap. A high-frequency probe having a surrounding shape. 5. The high-frequency probe according to claim 1, wherein the tip substrate includes a plurality of signal transmission paths corresponding to a plurality of signal electrodes on a surface pressed against the signal electrodes of the device under test. High frequency probe. 6. The high-frequency probe according to claim 5, wherein the signal transmission path forms a microstrip line on a surface of the tip substrate whose back surface is a solid ground surface, and a ground block is formed on the tip substrate. It has an electrical continuity with the solid ground plane, and has a shape surrounding the signal transmission path with a predetermined gap together with the solid ground plane and having a partition wall between each of the plurality of signal transmission paths. High frequency probe.