JP2008082734A - Electric contact device, high frequency measuring system, and high frequency measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive electric contact device which measures even a device having no ground electrode, and is suitable for measurement using an error correction model. <P>SOLUTION: The device has: a body (card body 41), a plurality of measuring probes 42A-42H tips arrayed along a pair or a plurality of pairs of virtual opposite sides; a plurality of signal connectors (coaxial connector 3b) connected electrically to a plurality of high frequency signal probes among the measuring probes directly or through an electric circuit; and a plurality of ground probes 43A-43H provided in each high frequency signal probe and connected electrically to a connector part held with a ground potential or to a ground connector. Each tip of the ground probes 43A-43H is placed close to each tip of the corresponding high frequency signal probes, and positioned on the outside of the virtual opposite side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrical contact device used when performing high-frequency measurement by making electrical contact with a chip-shaped or wafer-shaped device to be inspected, a high-frequency measurement system including the electrical contact device in a prober device, and the electrical The present invention relates to a high frequency measurement method capable of removing high frequency characteristics of a mechanical contact device from measurement results.

  In a high-frequency device, measurement of high-frequency electrical characteristics in a wafer state or a bare chip state is performed using various probes and probe cards.

For example, in the case of wafer measurement, a measurement device used for this measurement includes an LSI tester and a prober device. A probe card is detachably provided in the prober device. The probe card includes a large number of measurement probes. The arrangement of the plurality of measurement probes is adapted to the electrode pad arrangement of a chip-shaped high-frequency device formed on a wafer, which is a device under test (DUT).
On the other hand, the prober apparatus has a stage on which a semiconductor wafer on which a high-frequency device is formed is placed. The tip of the measurement probe is brought into contact with an electrode pad formed on the high frequency device of the wafer on the stage.
In this state, a high frequency signal and a bias voltage are sent from the LSI tester and applied to the electrode pads of the high frequency device. Then, an output signal (high-frequency signal) is generated on the other electrode pad of the high-frequency device, the LSI tester detects the output signal, and the measurement value is evaluated based on the detection result. In the inspection, this measurement and evaluation are repeated to discriminate between good products and defective products.

  Thus, the probe card has a role of electrically connecting the LSI tester and the electrode pads of the high-frequency device. In order to accurately measure the high-frequency characteristics of the device under test (high-frequency device), it is important to reduce the attenuation and reflection of the high-frequency signal on the transmission path of the probe card.

However, it is impossible to realize an ideal transmission path, and some attenuation and reflection exist in the transmission path. Therefore, in the measurement of the high frequency device, the high frequency characteristic of the high frequency signal transmission path of the probe card is measured, and the measured value is used as an error correction model. Here, the error correction model refers to a set of evaluation values representing a certain high frequency characteristic when the transmission path is regarded as an equivalent circuit model having a certain high frequency characteristic.
In the measurement using the error correction model, the error correction model is measured in advance with the probe card alone or with the probe card mounted on the wafer measurement board. Then, the high frequency device is measured and the error correction model is subtracted from the actually measured high frequency property to obtain a characteristic closer to the true value of the high frequency characteristic of the high frequency measuring device.

There are known methods and systems for calibrating a measurement path of a device under test in such a manner and measuring the device under test while being connected to the measurement path of the calibrated device under test (for example, Patent Document 1).
Moreover, a calibration method for vector-corrected electrical measurement values is known (see, for example, Patent Document 2).

  Some high-frequency devices include a signal electrode that inputs and outputs a high-frequency signal and a ground electrode that corresponds to the signal electrode. A typical example is a semiconductor device having a signal line pattern called a coplanar line. In this case, the high-frequency signal transmission path of the probe card also needs to include a signal conductor for passing the signal and a ground conductor corresponding to the signal and held at the ground potential.

A microwave wafer probe having a coaxial connector is known as an electrical contact device for a wafer that serves as a probe card (see, for example, Patent Document 3).
The microwave wafer probe described in Patent Document 3 is provided with a high-frequency signal probe and a ground probe adjacent to the high-frequency signal probe in alignment with the coplanar line of the high-frequency device. The central axis of the coaxial connector is connected to the high-frequency signal probe, and the ground probe is in electrical contact with the body portion of the coaxial connector.

A probe card using a coaxial needle that can be used for similar purposes is known (see, for example, Patent Document 4).
The probe card described in Patent Document 4 has a coaxial needle, that is, a ground-covered conductor formed by being insulated around a signal probe (core wire). The ground covered conductor is removed from the tip of the core wire of the coaxial needle, and a ground needle joined by a conductive adhesive is provided at the end of the ground covered conductor formed by the removal.

On the other hand, a high-frequency probe having a microstrip line wiring structure is known (see, for example, Patent Document 5).
Since the high-frequency probe described in Patent Document 5 has a microstrip line structure, a portion in contact with the electrode is provided at one end of one surface of the probe substrate, and a ground surface is formed on the back side of the probe substrate. Yes.
JP 2004-109128 A Japanese Patent Laid-Open No. 02-132377 Japanese Patent Laid-Open No. 02-187666 JP 2004-309257 A JP 2000-241444 A

By the way, the device under test needs a ground electrode in order to measure a high-frequency device, but there may be a case where only a signal electrode is present and there is no ground electrode corresponding to a high-frequency signal applied to the signal electrode.
In the electrical contact device including the probe card and the probe described in Patent Documents 3 and 4, high-frequency measurement cannot be performed on a device to be inspected without such a ground electrode.
In addition, the error correction model alone cannot perform high-frequency measurement of the electrical contact device. Therefore, when such an electrical contact device is used, it is not possible to apply a high-frequency measurement method that corrects an actual measurement value using an error correction model, resulting in poor measurement accuracy.

On the other hand, the high frequency probe having the microstrip line structure described in Patent Document 5 has a conductor (ground surface) held at the ground potential in the vicinity of the probe tip that contacts the signal electrode of the device under test. The high-frequency measurement of the error correction model is possible by devising how to make contact.
However, this high-frequency probe has a ground block that supports the tip substrate that forms the signal transmission path of the microstrip line structure, and the tip substrate is formed on the upper surface side thereof, so the lower part of the ground block is obstructive. Therefore, it is considered difficult to measure the device under inspection in the wafer state. Further, since the tip of the probe is easily bent when contacted by a flexible substrate, a plate spring for supporting the probe from the ground surface is required, and a large main body block for screwing the plate spring is also required, which has a complicated structure. For this reason, it is inevitable that the high-frequency probe is expensive.
Although it is preferable that the high-frequency probe has a microstrip line structure or a coaxial structure itself, these structures are not necessarily required if an error correction model is assumed. This is because if the high-frequency characteristic of the error correction model can be measured stably, the characteristic component is removed from the actual measurement value and error correction is performed, so the quality of the characteristic component (error component) is not a problem.

The problem to be solved by the present invention is that a high-frequency signal that can be measured even when the device to be inspected does not have an adjacent ground electrode corresponding to the signal electrode, and is suitable for measurement using an error correction model, is inexpensive. It is an object to provide an electrical contact device and a high-frequency measurement system comprising a probe.
Another problem to be solved by the present invention is to provide a high-frequency measurement method capable of acquiring high-frequency characteristics of a device under test alone using an apparatus having a configuration similar to that of the electrical contact apparatus.

The electrical contact device according to the present invention has a main body and a tip that is supported by the main body and arranged along one or more pairs of virtual opposing sides corresponding to the arrangement of the electrode pads of the device to be inspected. A plurality of measurement probes and a plurality of measurement probes provided in the main body for electrical connection directly or via an electric circuit to a plurality of high-frequency signal probes that receive or output a high-frequency signal among the plurality of measurement probes. A signal connector, and a plurality of ground probes provided for each of the high-frequency signal probes, supported by the main body, and electrically connected to a portion of the signal connector or a ground connector held at a ground potential. Each of the plurality of ground probes has a tip that is close to a tip of the corresponding high-frequency signal probe and is located outside the virtual opposing side.
Preferably, in the present invention, the tip of the ground probe and the tip of the corresponding high-frequency signal probe have a distance between both tips in a plane parallel to the main body from the center of the electrode pad of the device under test. It is set to be equal to or larger than the distance to the center of the width of the scribe line that is the wafer portion between the devices to be inspected.
More preferably, when the distance between the tips of the ground probe and the high-frequency signal probe is larger than the distance from the center of the electrode pad to the width center of the scribe line, it is inclined from the virtual line perpendicular to the virtual opposing side. The tip of the grounding probe is displaced with respect to the tip of the high-frequency signal probe.

  A high-frequency measurement system according to the present invention includes a prober device including an electrical contact device that makes electrical contact with a semiconductor device in a wafer state or a chip state, and a tester that is connected to the prober device and measures high-frequency characteristics of the semiconductor device. And the electrical contact device is supported by the main body, and tips are arranged along one or more pairs of virtual opposing sides corresponding to the arrangement of the electrode pads of the device under test. A plurality of measurement probes, and a plurality of high-frequency signal probes to which a high-frequency signal is input or output among the plurality of measurement probes are provided directly or via an electric circuit. A plurality of signal connectors and the signal connector provided for each of the high-frequency signal probes, supported by the body, and held at a ground potential. A plurality of ground probes electrically connected to a portion of the connector or a ground connector, wherein each of the plurality of ground probes has a tip close to a tip of the corresponding high-frequency signal probe, and It is located outside the virtual facing side.

  A high-frequency measurement method according to the present invention includes a plurality of measurement probes and tip signal connectors whose tips are arranged along one or more pairs of virtual opposing sides corresponding to the arrangement of electrode pads of a device under test. A high-frequency measurement method for measuring high-frequency characteristics of the device under test using an electrical contact device that includes a plurality of pairs of high-frequency signal probes and ground probes in the plurality of measurement probes. A tip and a signal connector electrically connected to the high-frequency signal probe; and a portion connected to a high-frequency measuring device and held at a ground potential of the signal connector or a ground connector; and A tip of one grounding probe that is close to the vicinity of the tip of the high-frequency signal probe and is located outside the virtual opposing side; and A first step of connecting to a ground potential of a fixed device, a second step of measuring high-frequency characteristics between the high-frequency signal probe connected to the high-frequency measuring device and the signal connector, and all other high-frequency signal probes. The first step and the second step are repeated, and the third step of acquiring the high frequency characteristics of the electrical contact device, and all of the grounding probes are not connected to the device under test when the device under test has a chip shape. If the device to be inspected is in the shape of a wafer, all the ground probes are not in contact with the wafer or in contact with the scribe line between the devices. A fourth step of contacting the plurality of measurement probes; and the plurality of signal connectors in the state of the fourth step. The high-frequency measuring device is connected to the cable and all the ground probes are commonly connected to the ground potential of the high-frequency measuring device, and the electrical contact device and the object to be covered are in the state of the fifth step. From the sixth step of measuring the synthesized high frequency characteristic of the inspection device and the characteristic obtained in the sixth step, the high frequency characteristic of the device under test alone is obtained using the characteristic obtained in the third step. And a seventh step.

According to the above-described electrical contact device and high-frequency measurement system of the present invention, a plurality of tips whose ends are arranged along one or more pairs of virtual opposing sides corresponding to the arrangement of the electrode pads of the device under test. Among the measurement probes, one high-frequency signal probe is provided with one ground probe whose tips are close to each other.
When the measurement probe of the electrical contact device is in electrical contact with the device to be inspected, when the device to be inspected has a chip shape, the ground probe is positioned outside the chip and is in a non-contact state with the chip. Become. On the other hand, when the device to be inspected has a wafer shape, in most cases, it contacts the scribe line between the chips, or when the scribe line is sufficiently lower than the electrode, it is not contacted above the scribe line because of the step. Become. Further, in the device at the end of the wafer, even when the level difference is small, the ground probe may be located outside the wafer and contactless. The scribe line is usually covered with an insulating film at the measurement stage whether the bare semiconductor substrate is exposed. Therefore, even if the ground probe contacts the scribe line, the measurement is not affected.

In the high frequency measurement method of the present invention using such an electrical contact device, the high frequency characteristics of the electrical contact device are measured and acquired by the high frequency measurement device in the first to third steps described above. At this time, since the high-frequency signal probe and the grounding probe are close to each other on the distal end side, electrical connection to both distal ends is easy, and the characteristics of the electrical contact device are accurately measured.
Next, contact for electrically connecting the device to be inspected to the electrical contact device is performed in the fourth step. At this time, all the high-frequency signal probes come into contact with the electrode pads of the device while the ground probe is in contact with the scribe line or is not in contact with the device. In the fifth step, the electrical contact device is connected to the high-frequency measuring device by a cable, and in the sixth step, high-frequency measurement is performed. The characteristic obtained by this measurement is a characteristic obtained by combining the characteristics of the electrical contact device and the device under test. Accordingly, error correction is performed in the next seventh step to obtain an accurate high frequency characteristic of the device under test alone.

According to the present invention, it is possible to perform measurement even when the device to be inspected does not have an adjacent ground electrode corresponding to the signal electrode, and it is suitable for measurement using an error correction model and is provided with an inexpensive high-frequency signal probe. A mechanical contact device and a high frequency measurement system can be provided.
In addition, it is possible to provide a high-frequency measurement method capable of acquiring high-frequency characteristics of a device under test alone using an apparatus having the same configuration as the electrical contact apparatus.

Embodiments of the present invention will be described below with reference to the drawings.
First, an outline of a high-frequency measurement system using a probe card as an electrical contact device according to this embodiment will be described.

[High-frequency measurement system]
FIG. 1 is a schematic configuration diagram of a high-frequency measurement system.
The illustrated high-frequency measurement system is roughly divided into a prober device 5 and an LSI tester 1.
The prober device 5 includes a main body 5A, a test head 5B, and a drive unit 5D that drives the test head 5B up and down via an arm 5C.

An XYZ table 8 is provided in the main body 5A, and a wafer stage 7 is provided thereon. A semiconductor wafer 6 is fixed on the wafer stage 7 by, for example, vacuum suction. A large number of semiconductor IC chips (hereinafter simply referred to as chips) as devices to be inspected are formed on the semiconductor wafer 6.
The XYZ table 8 can move the wafer stage 7 in three axes in the X direction, the Y direction, and the Z direction, and the semiconductor wafer 6 also moves as the wafer stage 7 moves.

A wafer measurement board 2 is provided between the main body 5A and the test head 5B. The wafer measurement board 2 may be fixed to the test head 5B side, but here, the wafer measurement board 2 is fixed on the main body 5A.
On the wafer measurement board 2, a measurement circuit of a chip as a device to be inspected (hereinafter referred to as DUT (device under test) 10 in the meaning of a device under inspection) is formed. This measurement circuit includes a DC power supply circuit, an interface circuit, and the like. The wafer measurement board 2 can be replaced with one corresponding to the device to be inspected.

  A probe card 4 is detachably attached to the lower surface of the wafer measurement board 2, that is, the surface on the DUT 10 side. In the probe card 4, the arrangement of the probe tip according to the arrangement between the electrodes of the DUT 10 is determined. Normally, if the DUT 10 is different, the probe card 4 is replaced with a corresponding one. However, the same probe card 4 may be used in a minor change semiconductor IC. Details of the probe card 4 will be described later.

When the test head 5B is moved upward by the drive unit 5D via the arm 5C, the DUT 10 can be visually recognized through the openings of the wafer measurement board 2 and the probe card 4. The test head 5B is lowered during the test, and the test environment can be prepared in that state to start the test. The test head 5B may be configured to provide a common interface with a high-frequency measurement system even if the type of the wafer measurement board 2 is different. In this case, as shown in the figure, the cable 3a from the LSI tester 1 is connected to a coaxial connector 3b, which is a type of signal connector, provided in the test head 5B. The coaxial connector 3b may be provided on the wafer measurement board 2, and a special device (for example, a high-frequency discrete device or a simple IC) requires almost no measurement circuit, so the measurement circuit and signal connector are used as a probe card. 4 may be provided in itself.
The cable 3a is generally a coaxial cable, and the coaxial connector 3b is also a coaxial connector.

In the present embodiment, the LSI tester 1 is provided with a vector network analyzer (VNA) 1A, a power supply unit 1B, and a control unit 1C as a high-frequency measuring device. The LSI tester 1 also has a measuring device for DC measurement, but this is not shown.
The vector network analyzer 1A is a measuring instrument that measures high-frequency characteristics (impedance, etc.) of a high-frequency circuit or device. The high-frequency characteristics of the circuit or element are measured by inputting a high-frequency to the circuit or element and measuring reflection and passage from the circuit or element. It is a device that measures.
The power supply unit 1B is a device that supplies DC power to be applied to the DUT 10 to the test head 5B or the wafer measurement board 2 via a cable (not shown) during high frequency measurement and DC measurement. The power supply unit 1B also supplies power to the vector network analyzer 1A and the control unit 1C.
The control unit 1C is a computer-based device, and controls the vector network analyzer 1A, the power supply unit 1B and other tester parts (for example, a DC measuring instrument and a switching relay circuit) in accordance with a built-in or externally installed program. Then, a predetermined test is executed.

FIG. 2 shows a simplified measurement path configuration of the high-frequency measurement system.
This measurement system exemplifies the simplest two-terminal measurement in which a high frequency signal is applied to one electrode pad of the DUT 10 and a signal (high frequency signal) from the other electrode pad is measured. In addition, when a high frequency signal is given to a plurality of electrode pads, even when a high frequency output signal is obtained from a plurality of electrode pads, the basics are as shown in the figure. Further explanation will be given.

The vector network analyzer 1A and the coaxial connector 3b are connected as shown (see FIG. 1).
The signal transmission path (transmission path A) 101A from the coaxial connector 3b to one signal input / output end (electrode pad) of the DUT 10 and the other signal input terminal (other electrode pad) of the DUT 10 from the other coaxial connector 3b. The signal transmission path (transmission path B) 101B up to) is a measurement path portion where an error correction model needs to be obtained.
Here, the calibration (calibration) from the vector network analyzer 1A itself and from the vector network analyzer 1A to the ends of the cable 3a used for actual measurement (two coaxial connectors 3b) has already been completed. Assuming that Under the premise, if the high-frequency characteristics of the signal transmission paths 101A and 101B can be measured, the high-frequency characteristics of the signal transmission paths 101A and 101B are considered from the measured values of the high-frequency measurement in the measurement system shown in FIG. By (normally subtracting), more accurate high-frequency characteristics of the DUT 10 can be obtained.

[Electric contact device]
The “electric contact device” of the present invention includes from the coaxial connector 3b connected to the high-frequency measuring device (vector network analyzer 1A) through the cable 3a to the probe tip that contacts the electrode pad of the DUT 10. .
Therefore, the electrical contact device of the present invention has various forms depending on where the coaxial connector 3b to be cable-connected to the high-frequency measuring device is provided.

For example, in the high-frequency measurement system shown in FIG. 1, when the coaxial connector 3b is provided on the wafer measurement board 2, the signal path (including the electric circuit) in the wafer measurement board 2 from the coaxial connector 3b, the wafer measurement board 2 And the probe card 4 and the signal path in the probe card 4 are included in the electrical contact device.
When the coaxial connector 3b is provided on the probe card 4, the signal path in the probe card 4 (including the electrical circuit if it has an electrical circuit) and the signal path to the probe end are electrically connected. Included in contact device.
On the other hand, when the coaxial connector 3b is provided in the test head 5B, not only the signal path of the wafer measurement board 2 and the probe card 4, but also the signal path in the test head 5B (if it has an electrical circuit, the electrical circuit thereof). Are included in the electrical contact device.

  Hereinafter, in order to simplify the drawings and description, the detailed configuration of the electrical contact device (probe card 4) according to the present embodiment will be described by taking as an example the case where the coaxial connector 3b is provided on the probe card 4.

FIG. 3B is a schematic cross-sectional view of the probe card 4 in contact with the semiconductor wafer 6.
The probe card 4 has a card body 41, a plurality of coaxial connectors 3 b fixed to the upper surface of the card body 41, a measurement probe 42 whose tip is in contact with the semiconductor wafer 6, and a tip which is in contact with the semiconductor wafer 6. And a probe holding part 44 for holding the measurement probe 42 and the ground probe 43 on the lower surface side of the card body 41 and fixing them to the card body 41.
The measurement probe 42 and the ground probe 43 are both bent at one end (downward in the figure) and the tips are in contact with the semiconductor wafer 6.
The card body 41 has an opening 41A at the center.

FIG. 3A is a view as seen from above the opening 41A.
On the semiconductor wafer 6, semiconductor IC chips (DUTs 10) surrounded by grid-like scribe lines 61 are regularly arranged.
In the DUT 10, electrode pads 11A to 11H are provided in regions along the pair of opposing sides. The electrode pad may also be provided in a region along another pair of opposite sides.

In FIG. 3, whether any of the electrode pads 11 </ b> A to 11 </ b> H is input or output with a high frequency signal or another low frequency signal or DC voltage is arbitrary. That is, if the electrode arrangement of the DUT 10 is the same, the probe card 4 has a high versatility because the electrode pad usage method, that is, the correspondence between the electrode pad and the signal or voltage is arbitrary. Therefore, all the measurement probes 42A to 42H can be used as high-frequency signal probes to which high-frequency signals are input or output.
The tips of the measurement probes 42A to 42H are in contact with any of the corresponding electrode pads 11A to 11H.

Each of the measurement probes 42A to 42H is provided with any one of the ground probes 43A to 43H. Further, any one of coaxial connectors 3bA to 3bH is provided for two pairs of probes (measurement probe 42 and ground probe 43, hereinafter also referred to as a probe pair).
For example, the measurement probe 42A is provided with a ground probe 43A close to its two tips, the measurement probe 42A is electrically connected to the axis of the coaxial connector 3bA, and the ground probe 43A has a ground potential. It is electrically connected to the body part applied when the cable is connected.
The relationship between the close arrangement of the probe tips and the electrical connection is the same for the other measurement probes 42B to 42H.

However, the tips of the ground probes 43A to 43H are located on the outside in the facing direction of the virtual facing sides formed by the tips of the measurement probes 42A to 42H.
When the relationship is representatively shown in FIG. 3C as a pair of probes, the linear distance D2 between the tips of the measurement probe 42 and the ground probe 43 is from the center of the electrode pad 11 where the tip of the measurement probe 42 is located. It is larger than the shortest linear distance D1 to the center of the scribe line 61 in the width direction. This is a result of disposing the measurement probe 42 and the ground probe 43 so as to be easily seen from the upper surface. However, the two distances D1 and D2 may be the same.

In the present invention, it is sufficient that at least two of the measurement probes are paired with the measurement probe and the ground probe.
FIG. 4 shows a top view of the probe card 4 having two pairs of probes arranged close to each other.
A ground probe 43C is provided for the measurement probe 42C that contacts the electrode pad 11C of the DUT 10, a ground probe 43F is provided for the measurement probe 42F that contacts the electrode pad 11F, and a ground probe is provided for the other measurement probes 42. Not.
When high frequency signal probes are determined, the number of ground probes is provided in this way. In the present embodiment, an arbitrary number of probe pairs can be provided in the range of 3 pairs or more and 7 pairs or less.
The above configuration is similarly applied to the case where electrical contact is made on the remaining opposing side of the DUT 10 even when the number of electrode pads is not eight.

FIG. 5 shows a connection structure between the probe pairs 42 and 43 and the coaxial connector 3b.
A signal connection wiring 45 is formed on the lower surface of the card body 41, whereby the measurement probe 42 and the axial external terminal 31 of the coaxial connector 3b are electrically connected.
A ground connection wiring 46 is formed on the upper surface of the card body 41, whereby the ground probe 43 and the body portion 32 of the coaxial connector 3b are electrically connected.
In addition, although the material of the probe holding | maintenance part 44 is arbitrary, it consists of resin, for example.

As a reference example, FIG. 6A shows a top view of a probe card when the present invention is not applied, and FIG. 6B shows a cross section thereof.
Comparing this reference example with FIG. 3 and FIG. 4 relating to the present embodiment, it can be seen that at least two ground probes 43 held at the ground potential are added in the present embodiment.

[High-frequency measurement method]
FIG. 7 is a flowchart showing a measurement procedure of the high-frequency measurement method in the present embodiment.
In step ST1, calibration at the end of the coaxial cable is performed. In this calibration, instead of the signal transmission lines 101A and 101B and the DUT 10 shown in FIG. 2, a through, open, short circuit is provided between the open end of the cable 3a and the open end of the other cable 3a. A predetermined standard called “short” and “load” are sequentially connected, and each time, a measurement for obtaining a scattering parameter (S parameter) is performed by the vector network analyzer 1A. Note that the type of standard differs depending on the calibration method, and is not limited to the above four examples.
As a result, variations due to the state of the vector network analyzer 1A, signal reflection at the connection end, signal delay due to the cable, and the like are corrected.

Next, in step ST2 of FIG. 7, the probe card 4 is connected.
FIG. 8 shows the connection method.
The probe card 4 shown in FIG. 3B is attached to the fixing jig 120 in FIG. 8 with the needle tips of the measurement probe 42 and the ground probe 43 facing upward, for example. Then, the calibrated cable 3 a connected to one terminal of the vector network analyzer 1 A is connected to the coaxial connector 3 b of the probe card 4. Further, a high-frequency prober 110 having a measurement head 112 capable of contacting the tips of at least two probes is connected to another calibrated cable 3a connected to the other terminal of the vector network analyzer 1A. The illustrated high-frequency prober 110 includes a coaxial connector 111, and the coaxial connector 111 is connected to the coaxial connector at the tip of the cable 3a. In this state, the high-frequency prober 110 is attached to a stage that can move in three axes of the fixing jig 120.

Thereafter, the stage is controlled, and the measurement probe 42 and the ground probe 43 are compared with the two probes 113 and 114 provided on the measurement head 112 of the high-frequency prober 110 as shown in FIG. In contact with each other.
In this state, a high-frequency test signal is applied to the probe card 4 from the vector network analyzer 1A, and the high-frequency characteristics from the measurement probe 42 to the axis of the coaxial connector 3b are measured from the ground probe 43 to the ground fuselage of the coaxial connector 3b. Is obtained in a sufficiently grounded state. Thereby, step ST3 (preliminary measurement) in FIG. 7 ends.
When the probe card 4 has a plurality of high-frequency signal transmission paths, measurement is performed for each. For example, in the case of FIG. 3A, since there are eight measurement probes that can serve as a transmission path for a high-frequency signal, the preliminary measurement is performed for each of the eight measurement probes 42A to 42H. On the other hand, in FIG. 4, since the high-frequency probe is one of the measurement probes 42C, the preliminary measurement is performed on the measurement probe.
The high-frequency characteristics of the probe card 4 are temporarily stored in a predetermined storage area of the control unit 1C shown in FIG.

  In step ST4 of FIG. 7, the probe card 4 whose signal path has been calibrated (high-frequency characteristics have been acquired) is removed from the fixing jig 120 shown in FIG. 8, and set in the prober device 5 shown in FIG. Then, the cable 3a already calibrated and used in the preliminary measurement of FIG. 8 is connected to a predetermined coaxial connector of the prober device 5 (in this example, the coaxial connector 3b provided on the probe card 4).

Next, by controlling the XYZ table 8 in the prober device 5, as shown in FIG. 3A or 4, the measurement probes 42A to 42H are placed on the electrode pads 11A to 11H provided in the DUT 10 to be measured. The contact is made with sufficient needle pressure (step ST5). At this time, the ground probes 43 </ b> A to 43 </ b> H are in contact with the scribe line 61. Alternatively, when the height difference between the electrode pad and the scribe line, that is, the step in the thickness direction of the semiconductor wafer 6 is relatively large, the ground probes 43 </ b> A to 43 </ b> H may not reach the scribe line 61. However, in either case, the ground conductor (ground probe) is close to the signal path (high frequency probe) in the same state as in the preliminary measurement, and the influence on the measurement accuracy is constant.
In this state, the main measurement is performed in step ST6, and various high frequency characteristics are performed in accordance with a predetermined program.

After the actual measurement, in step ST7, the error correction model, that is, the evaluation value of the high frequency characteristics of the electrical contact device (probe card 4) obtained in the preliminary measurement in step ST3 is used as the actual measurement obtained in step ST6. Subtract from the evaluation value. This calculation is executed according to a predetermined program using the result of the main measurement input from the vector network analyzer 1A by the control unit 1C shown in FIG. 1 and the result of the preliminary measurement temporarily stored.
As a result, as shown in step ST8 of FIG. 7, more accurate high frequency characteristics of the device under test (DUT 10) can be obtained. Thereafter, if necessary, the measurement target is changed, the above steps ST5 to ST8 are repeated as many times as necessary, and the measurement result is displayed or printed, thereby completing the high frequency measurement.

[Modification]
Hereinafter, variations of the present embodiment will be described.
The measurement probe in the above description is a cantilever type that protrudes from the probe holding portion 44 as shown in FIG. Even in the same cantilever type, for example, the probe holding portion 44 may be provided with a screw capable of adjusting the position of the needle tip so that the relative positional relationship between the needle tips of the measurement probe 42 and the ground probe 43 can be changed. However, in this case, if the positional relationship of the needle tip is changed, the high frequency characteristics also change. Therefore, after adjusting the positional relationship of the needle tip according to the device to be measured, the preliminary measurement shown in FIG. It is necessary to perform this measurement without changing the positional relationship of

  Further, when the same coaxial needle as in Patent Document 4 described above is used, the tip of the ground needle joined to the end of the ground coating conductor by a conductive adhesive is connected to a high-frequency signal as shown in FIG. The present invention can also be applied by positioning it outside the virtual opposing side formed by the tip of the probe.

Furthermore, a structure having a microstrip structure conductor that can be deformed by pressure from the outside and embedded in a metal having a blade shape in an insulating state, for example, and a probe attached to the end of the conductor may be used.
Further, the entire probe may be formed from a deformable conductive material.
However, in any case, it is necessary not only to adjust the position of the needle tip but also to change the entire deformable signal path between the preliminary measurement and the main measurement.

  Furthermore, regarding the shape and material of the probe and its support structure, the probe is not limited to a pointed needle, and may be in surface contact. Hereinafter, an example of the measurement probe capable of surface contact will be described with reference to the drawings.

FIG. 9 shows a surface contact type probe card having a so-called membrane type support.
In the illustrated probe card 4A, the card body 41B does not have an opening. A membrane-type support base 47 having an inclined tapered portion and two-dimensionally expanding is fixed to the lower surface of the card body 41B. Flexible substrates 42x and 42y as measurement probers are arranged along the oblique taper portion of the membrane-type support base 47, and flexible substrates 43x and 43y are arranged as ground probers on the outer sides thereof. This flexible substrate has a three-layer structure in which both sides in the thickness direction of a conductive film serving as a high-frequency signal transmission line or a ground potential conductor are covered with an insulating thin film.
Although the illustrated flexible substrates are two pairs, the four taper portions of the membrane-type support base 47 are provided in the required number of the predetermined taper portions.

A cap-shaped outer support portion 48 that is slightly larger than the membrane-type support base 47 is attached so that a gap of two sheets is formed by a combination of the flexible substrates 42x and 43x or 42y and 43y.
The flexible substrates 42x and 42y that transmit high-frequency signals have their ends bent to the inside of the membrane-type support base 47 and fixed to the lower surface (flat surface) of the support base 47. At each end of the flexible substrates 42x and 42y, a part of the insulating thin film on the lower surface side is removed, and surface contact conductors 49x and 49y are formed in the portions.
On the other hand, the end portions of the flexible substrates 43 x and 43 y to which the ground potential is applied are fixed to the lower surface of the outer support portion 48. At each end of the flexible substrates 43x and 43y, a part of the insulating thin film on the lower surface side is removed, and surface contact conductors 50x and 50y are formed in the portions.

As shown in the figure, when contacting the semiconductor wafer 6, the surface contact conductors 49x and 49y provided at the tip portions of the flexible substrates 42x and 42y are in surface contact with the electrode pads 11x and 11y of the DUT 10, respectively. At this time, the other surface contact conductors 50 x and 50 y are not in contact with the scribe line 61. However, as described above, this state does not affect the measurement accuracy.
At the other end of the flexible boards 42x and 42y, a conductive film as a high-frequency signal transmission path is connected to the external terminal 31 of the coaxial connector 3b. Further, at the other end of the flexible substrates 43x and 43y, a conductive film as a ground potential conductor is connected to the body portion 32 of the coaxial connector 3b via a ground connection wiring 46.
Therefore, the electrical connection between the electrode pads 11x and 11y of the DUT 10 and the coaxial connector 3b is realized as in FIG.

  Since the probe card 4A is a surface contact type, there is an advantage that the surface of the electrode pads 11x and 11y can be prevented from being damaged and the contact resistance is small. The flexible substrates 42x and 43x or 42y and 43y forming the probe pair are similar to so-called microstrip lines if the conductive films in the flexible substrates 43x and 43y to which the ground potential is applied are relatively wide. It becomes a structure and the impedance fluctuation of a signal line can be suppressed by noise or the like. Moreover, since it is a flexible substrate, the cost is relatively low.

The support structure of the region A surrounded by the broken-line circle in FIG. 9 can be changed, for example, as shown in FIG. 10 (A) or FIG. 10 (B).
That is, instead of the membrane-type support base 47, the inner support member 47A or 47B is provided in FIG. 10, and the outer support member 48A or 48B is provided in FIG.
FIG. 10A is a structural example in which the tip portions of the flexible substrate pairs 42y and 43y are supported from the side in contact with the flexible substrate pair, and FIG. 10B is a structural example in which the tip portions are supported from the outside. Various other support methods can be used.

FIG. 11 shows a modification example of the region B surrounded by a broken-line circle in FIG. This change can be combined with FIG. 10A or FIG. 10B.
In FIG. 11, anisotropic conductive rubber 51 is interposed between the surface contact conductors 49x and 49y and the electrode pads 11x and 11y. This is provided in common with a plurality of measurement probes, in this figure flexible substrates 42x and 42y. The anisotropic conductive rubber 51 may be common to all the measurement probes or may be provided for several measurement probes. For example, referring to FIG. 3 (A), for each line arranged inline, in the example shown in FIG. 3 (A), one is measured probe 42A-42D and one is measured by other measurement probes 42E-H. An anisotropic conductive rubber 51 may be provided. In any case, the anisotropic conductive rubber 51 is fixed to the surface contact conductor of the measurement probe with a conductive adhesive or the like.
As shown in FIG. 11, the anisotropic conductive rubber 51 exhibits conductivity only at a local portion where the pressure is applied when a pressure is applied. Therefore, the insulation between the electrode pads is maintained.
As described above, when the anisotropic conductive rubber 51 is used, the contact resistance is sufficiently low, and the electrode pad can be further hardly damaged.
In addition, various modifications can be made without departing from the spirit of the present invention.

According to this embodiment, high-frequency measurement can be performed with high accuracy in a wafer state or a chip state with respect to a high-frequency device having no ground electrode. This is due to the following reason.
A grounding probe is provided in a pair with a high-frequency signal probe that transmits a high-frequency signal among a plurality of measurement probes, their tips are close to each other, and the height from the card body is substantially uniform. Therefore, high frequency measurement (preliminary measurement) is possible using a general high frequency prober 110 having probes 113 and 114 having the same height as shown in FIG.
Further, when measuring an actual high-frequency device (DUT 10), the tip of the ground probe is located outside the virtual opposing side formed by the tips of the plurality of measurement probes, so that the circuit portion of the DUT 10 is damaged or other There is no contact with the electrode pad. Even if the grounding probe contacts the semiconductor wafer, the positional relationship between the tips of the probe pair is set so that it becomes a scribe line.
For the above reasons, it is possible to apply an error correction method that measures the unique high-frequency characteristics of the electrical contact device including this probe pair, and removes the characteristics from the results of device measurement performed using the electrical contact device. And Therefore, high-frequency device measurement with higher accuracy is possible.

Moreover, although the electrical contact apparatus of this embodiment is not basically a microstrip line structure, the measurement accuracy is still high. This is because it is important that the preliminary measurement for measuring the jig characteristics is stable, that is, it is possible to obtain almost the same result by a plurality of measurements, and the quality of the characteristics is not a problem. This is because the result of the preliminary measurement is finally excluded from the device evaluation result regardless of whether the characteristics are good or bad.
Therefore, the electrical contact device of this embodiment including various modifications can be manufactured at a lower cost than a high-frequency probe having a highly accurate microstrip line structure.

1 is a schematic configuration diagram of a high-frequency measurement system according to an embodiment of the present invention. It is the simplified measurement path figure at the time of a high frequency measurement. (A) is a top view when a needle is placed on a wafer, (B) is a cross-sectional view of an electrical contact device (probe card) according to the present embodiment, and (C) is an explanatory diagram of a relative positional relationship between probe tips. . It is a top view which shows the example of a change of FIG. It is a partial cross section figure of the probe card which shows the connection of a probe and a coaxial connector. (A) and (B) are the top view and sectional drawing of a reference example. It is a flowchart which shows the procedure of the high frequency measuring method in connection with this embodiment. It is a connection diagram which shows the method of preliminary measurement. It is sectional drawing which shows a modification. (A) And (B) is a partial cross section figure which shows the change of the support structure in FIG. FIG. 10 is a partial view showing a changed part of a contact portion in FIG. 9.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... LSI tester, 1A ... Vector network analyzer, 1B ... Power supply part, 1C ... Control part, 2 ... Wafer measurement board, 3a ... Cable, 3b ... Coaxial connector, 4, 4A ... Probe card, 5 ... Prober device, 5A ... Main body, 5B ... Test head, 5C ... Arm, 5D ... Drive unit, 6 ... Semiconductor wafer, 7 ... Wafer stage, 8 ... XYZ table, 10 ... DUT, 11 etc ... Electrode pad, 41, 41B ... Card body, 41A ... opening, 42, etc .... measurement probe, 43 ... ground probe, 44 ... probe holding part, 45 ... signal connection wiring, 46 ... ground connection wiring, 47 ... membrane-type support base, 48 ... outer support part, 49x, 49y, 50x, 50y ... surface contact conductor, 51 ... anisotropic conductive rubber, 101A, 101B ... signal transmission path, 110 ... high frequency prober, 111 ... Axial connector 112 ... measurement head, 113, 114 ... probe 120 ... fixing jigs

Claims (8)

The body,
A plurality of measurement probes supported by the main body and having tips arranged along one or more pairs of virtual opposing sides corresponding to the arrangement of the electrode pads of the device under test;
A plurality of signal connectors provided in the main body for electrical connection directly or via an electric circuit to a plurality of high-frequency signal probes to which high-frequency signals are input or output among the plurality of measurement probes;
A plurality of ground probes provided for each of the high-frequency signal probes, supported by the main body, and electrically connected to a portion of the signal connector or a ground connector held at a ground potential;
Have
Each of the plurality of ground probes is an electrical contact device in which each tip is close to the tip of the corresponding high-frequency signal probe and is located outside the virtual facing side. The tip of the ground probe and the tip of the corresponding high-frequency signal probe are such that the distance between the two tips in a plane parallel to the main body is from the center of the electrode pad of the device under test to the wafer between the devices under test. The electrical contact device according to claim 1, wherein the electrical contact device is set to be equal to or larger than a distance to a width center of a scribe line as a part. When the distance between the tips of the ground probe and the high-frequency signal probe is larger than the distance from the center of the electrode pad to the width center of the scribe line, it is obliquely displaced from the virtual line perpendicular to the virtual opposing side, The electrical contact device according to claim 2, wherein a tip of the ground probe is disposed with respect to a tip of the high-frequency signal probe. 4. The electrical contact device according to claim 1, wherein each of the plurality of measurement probes including the high-frequency signal probe and the grounding probe has a probe conductor having a pointed tip that performs point contact. 5. The electrical contact device according to claim 1, wherein each of the plurality of measurement probes including the high-frequency signal probe and the ground probe includes a conductor surface that performs surface contact at a tip. Each of the plurality of measurement probes including the high-frequency signal probe and the ground probe includes a conductor surface for each probe that makes surface contact, and a common anisotropic conductive member between the plurality of probes. The contact between the plurality of probes and the plurality of electrode pads of the device to be inspected is made by utilizing the fact that the anisotropic conductive member is locally conductive at the pressure of The electrical contact device as described. A prober apparatus including an electrical contact device for making electrical contact with a semiconductor device in a wafer state or a chip state;
A tester connected to the prober device and measuring high-frequency characteristics of the semiconductor device,
The electrical contact device comprises:
The body,
A plurality of measurement probes supported by the main body and having tips arranged along one or more pairs of virtual opposing sides corresponding to the arrangement of the electrode pads of the device under test;
A plurality of signal connectors provided in the main body for electrical connection directly or via an electric circuit to a plurality of high-frequency signal probes to which high-frequency signals are input or output among the plurality of measurement probes;
A plurality of ground probes provided for each of the high-frequency signal probes, supported by the main body, and electrically connected to a portion of the signal connector or a ground connector held at a ground potential;
Have
Each of the plurality of ground probes has a tip that is close to a tip of the corresponding high-frequency signal probe and is located outside the virtual facing side. A plurality of measurement probes and tip connectors arranged along one or more pairs of virtual opposing sides corresponding to the arrangement of the electrode pads of the device to be inspected are provided. A high-frequency measurement method for measuring high-frequency characteristics of the device under test using an electrical contact device including a plurality of pairs of signal probes and ground probes,
A portion in which the tip of one high-frequency signal probe and one signal connector electrically connected to the high-frequency signal probe are cable-connected to the high-frequency measuring device and held at the ground potential of the signal connector Alternatively, a first step of connecting a ground connector and a tip of one ground probe located near the tip of the high-frequency signal probe and outside the virtual facing side to a ground potential of the high-frequency measurement device; ,
A second step of measuring high-frequency characteristics between the high-frequency signal probe connected to the high-frequency measuring device and the signal connector;
Repeating the first and second steps for all other high frequency signal probes to obtain a high frequency characteristic of the electrical contact device;
All of the ground probes are in non-contact with the device to be inspected when the device to be inspected is in a chip shape, or all of the ground probes are in non-contact with the wafer or in the case of the device to be inspected in a wafer shape A fourth step of bringing the plurality of measurement probes into contact with the plurality of electrode pads of the device to be inspected so as to be in contact with the scribe line therebetween;
A fifth step of connecting the high-frequency measuring device to the plurality of signal connectors in the state of the fourth step, and connecting all the ground probes in common with a ground potential of the high-frequency measuring device;
A sixth step of measuring the combined high frequency characteristics of the electrical contact device and the device under test in the state of the fifth step;
From the characteristic obtained in the sixth step, a seventh step of obtaining the high frequency characteristic of the device under test alone using the characteristic obtained in the third step;
A high frequency measurement method including:

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