Probe apparatus

A probe apparatus 10 has a movable mounting table 12 that mounts a wafer W on which multiple power devices are formed; a probe card 14 that is provided above the mounting table 12 and has multiple probes 14A; a conductive film electrode 13 formed on a mounting surface of the mounting table 12 and an outer peripheral surface thereof; and a measurement line 16 that electrically connects the conductive film electrode 13 to a tester 17. Further, the probe apparatus measures electrical characteristics of the power devices on the mounting table 12 at a wafer level. Furthermore, the measurement line 16 includes a switch device 18 configured to open and close an electric path of the measurement line 16 between the conductive film electrode 13 and the tester 17.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a U.S. national phase application under 35 U.S.C. §371 of PCT Application No. PCT/JP2012/069923 filed on Jul. 30, 2012, which claims the benefit of Japanese Patent Application No. 2011-225335 filed on Sep. 22, 2011, the entire disclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The embodiments described herein pertain generally to a probe apparatus configured to measure electrical characteristics (static characteristics and dynamic characteristics) of a power device.

BACKGROUND

A power device has been widely used as a component for various kinds of power supplies or for electric devices of motor vehicles, or as a component for electric devices of industrial machines. As compared with a typical semiconductor device, the power device has a high breakdown voltage and a high current, and also has a high speed and a high frequency depending on an application thereof. Examples of the power device include an IGBT, a diode, a power transistor, a power MOS-FET, a thyristor, and the like. When these power devices are selected as high quality products through measurement of electrical characteristics (static characteristics and dynamic characteristics) thereof, they come into the market depending on applications thereof.

A probe apparatus has been widely used as a testing apparatus configured to measure electrical characteristics of a semiconductor device such as a memory device or the like while a power device is not separated from a wafer. The probe apparatus typically includes a loader chamber and a prober chamber adjacent thereto. While a wafer is transferred into the loader chamber, pre-alignment is carried out, and after electrical characteristics of the wafer loaded from the loader chamber are measured in the prober chamber, the measured wafer is returned back to the loader chamber. Recently, various technologies for applying such a probe apparatus to measurement of electrical characteristics of a power device have been developed, and a probe apparatus that measures static characteristics, such as resistance or the like, of a power device has been developed and commercialized.

FIG. 4is a conceptual diagram showing an example of a conventional probe apparatus.FIG. 4illustrates a prober chamber of a probe apparatus configured to measure static characteristics of a power device at a wafer level.

As depicted inFIG. 4, the prober chamber includes a movable mounting table1configured to mount a wafer W thereon, and a probe card2provided above the mounting table1. On a surface of the mounting table1, a conductive film electrode3(shown as a thick line inFIG. 4) made of a conductive metal such as gold or the like is formed. This conductive film electrode3is electrically connected to a tester5via a measurement line4(for example, cable).

If the probe apparatus depicted inFIG. 4measures static characteristics of a power device at a wafer level, when the wafer W is mounted on the mounting table1, a collector electrode of the power device on a lower surface of the wafer W is brought into electrical contact with the conductive film electrode3of the mounting table1. When the probe card2is brought into contact with this wafer W, a gate electrode and an emitter electrode of the power device are electrically connected to multiple probes2A. In this state, if a voltage is applied from the probe2A to the gate electrode of the power device, a high current flows from the tester5to the measurement line4, the conductive film electrode3, the collector electrode, and the emitter electrode. In this case, static characteristics, such as resistance or the like, of the power device are measured via other probes2A. Further, inFIG. 4, the probe card2is fixed to a head plate6via a clamp device (not illustrated).

As described above, a probe apparatus that measures static characteristics of a power device has been commercialized. However, a probe apparatus configured to measure dynamic characteristics of a power device is still under development and does not reach a level of commercialization. For this reason, dynamic characteristics of a power device need to be measured during a packaging process, and if a package product is evaluated as a defective product, it is wasted. Therefore, production yield of a power device as a product is deteriorated, so that defective products are likely to be produced.

Further, the present applicant developed a probe apparatus capable of measuring dynamic characteristics of a power device based on the probe apparatus depicted inFIG. 4(see Patent Document 1). That is, in the probe apparatus described in Patent Document 1, the same measurement line as the measurement line4depicted inFIG. 4is provided at the mounting table of the probe apparatus, so that both of static characteristics and dynamic characteristics of the power device can be measured with a single probe apparatus.

REFERENCES

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

However, in the probe apparatus depicted inFIG. 4, the conductive film electrode3of the mounting table1is continuously connected to the tester5through the measurement line4. Therefore, in the probe apparatus described in Patent Document 1 in which the same measurement line as the measurement line4is provided, it has been found that when dynamic characteristics, such as a switching characteristic, of a power device are measured, inductance of the measurement line4serves as an obstacle, so that the dynamic characteristics cannot be measured with high accuracy.

In view of the foregoing problems, example embodiments provide a probe apparatus capable of measuring both of static characteristics and dynamic characteristics of a power device at a wafer level, and particularly capable of surely measuring dynamic characteristics of a power device at a wafer level without being affected by a measurement line that measures static characteristics.

Means for Solving the Problems

In order to solve the above-mentioned problems, in a first example embodiment, a probe apparatus has a movable mounting table that mounts a target object on which multiple power devices are formed; a probe card that is provided above the mounting table and has multiple probes; a conductive film electrode formed on at least a mounting surface of the mounting table; a first measurement line that electrically connects the conductive film electrode to a tester via the probe card and measures dynamic characteristics of the power devices; and a second measurement line that electrically connects the conductive film electrode to the tester and measures static characteristics of the power devices. Further, the probe apparatus is configured to measure the static characteristics or the dynamic characteristics of the power devices by electrically connecting the multiple probes with multiple electrodes of each of the power devices of the target object mounted on the mounting table. Here, the second measurement line includes a switch device configured to open and close the second measurement line between the conductive film electrode and the tester.

In the first example embodiment, the switch device may include a relay switch device.

In the first example embodiment, the switch device may include a solenoid device and a contactor configured to be electrically attached and detached to and from the conductive film electrode via the solenoid device.

In the first example embodiment, the first measurement line may include a conductor provided between the conductive film electrode and the probe card.

Effect of the Invention

In accordance with example embodiments, a probe apparatus can measure both of static characteristics and dynamic characteristics of a power device at a wafer level, and particularly can surely measure dynamic characteristics of a power device at a wafer level without being affected by a measurement line that measures static characteristics.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a probe apparatus in accordance with an example embodiment will be explained with reference toFIG. 1toFIG. 3.

FIG. 1is a conceptual diagram showing a probe apparatus in accordance with an example embodiment.

A probe apparatus10in accordance with the present example embodiment is configured to receive a wafer W in a prober chamber11from a loader chamber (not illustrated) that transfers the wafer W, and to measure electrical characteristics (static characteristics and dynamic characteristics) of multiple power devices formed on the wafer W within the prober chamber11, as depicted in, for example,FIG. 1.

As depicted inFIG. 1, within the prober chamber11, a mounting table12configured to mount the wafer W thereon is provided to be movable in directions of X, Y, Z, and θ. Further, on the entire surface of a mounting surface of a chuck top12A of the mounting table12and the entire surface of a circumferential surface thereof, a conductive film electrode13(shown as a thick line inFIG. 1) made of a conductive metal such as gold or the like is formed as a collector electrode. The chuck top12A includes a vacuum-attraction unit configured to vacuum-attract the wafer W on the mounting surface of the chuck top12A. Further, the mounting table12accommodates a temperature control unit therein, and is configured to heat or cool the wafer W to be a preset temperature and configured to measure electrical characteristics (static characteristics and dynamic characteristics) of the power devices. The conductive film electrode13includes a first conductive film electrode member13A formed on the entire surface of the mounting surface of the chuck top12A and a second conductive film electrode member13B formed on the entire surface of an outer peripheral surface of the chuck top12A.

Above the mounting table12, as depicted inFIG. 1, a probe card14provided with a card holder is fixed to a head plate11A, which forms an upper surface of the prober chamber11, via a clamp mechanism (not illustrated). At a central portion on a lower surface of the probe card14, multiple probes14A are provided. These probes14A are configured to be electrically connected to a gate electrode and an emitter electrode of each of the power devices formed on the wafer W and measure electrical characteristics of the power devices.

Further, the probe apparatus10in accordance with the present example embodiment includes a first measurement line15that measures dynamic characteristics of the power devices and a second measurement line16that measures static characteristics of the power devices as described below.

As depicted inFIG. 1, the first measurement line15includes, for example, multiple conducting pins15A arranged at preset intervals along an outer periphery of the lower surface of the probe card14in a circumferential direction thereof, and a cable15B electrically connected to the multiple conducting pins15A via a conductive member (not illustrated). The other end of the cable15B is electrically connected to a tester17. The conductive member configured to connect the conducting pins15A and the cable15B is provided on the lower surface of the probe card14. The multiple conducting pins15A are configured to be electrically attached and detached to/from the first conductive film electrode member13A by moving the chuck top12A up and down through an elevation driving device (not illustrated) embedded in the mounting table12. Like, for example, pogo pins, the conducting pins15A have elasticity and are configured to be elastically brought into contact with the first conductive film electrode member13A. These conducting pins15A may be desirably formed on multiple places at preset intervals along the outer periphery of the probe card14, but may be formed on a single place.

When dynamic characteristics of the power devices are measured, the chuck top12A of the mounting table12is raised by a certain amount. Thus, the first conductive film electrode member13A (collector electrode) of the chuck top12A is brought into electrical contact with the conducting pins15A, and the tester17is electrically connected to the conductive film electrode (collector electrode)13of the chuck top12A via the first measurement line15. Further, the multiple probes14A are brought into electrical contact with the gate electrode and the emitter electrode of each of the power devices formed on the wafer W mounted on the chuck top12A. In this state, if a preset voltage is applied from the tester17to the gate electrode of the power device, a high current flows from the tester17to the first conductive film electrode member13A of the chuck top12A via the first measurement line15, and this current flows from the collector electrode of the power device to the tester17through the emitter electrode. Since the first measurement line15has a short length, inductance is low. Therefore, it is possible to surely measure dynamic characteristics of the power devices without being affected by the inductance.

Further, the second measurement line (cable)16electrically connects the tester17to the second conductive film electrode member13B and is configured to measure static characteristics of the power devices. Desirably, this measurement line16may have a short length to suppress affection of electromagnetic interference from its surroundings as much as possible, and in the present example embodiment, it is set to be about 2000 mm. This measurement line16includes a switch device18configured to open and close an electric path between the second conductive film electrode member13B and the tester17. This switch device18separates the second measurement line16from the chuck top12A by opening a switch to suppress affection of the inductance of the second measurement line16when dynamic characteristics of the power devices are measured as described above.

Examples of the switch device18may include, for example, a relay switch device, a solenoid switch device, and a cylinder switch device. Depending on a kind of the switch device18, a connection example between the second measurement line16and the second conductive film electrode member13B varies as depicted inFIG. 2andFIG. 3.FIG. 2illustrates a probe apparatus having a relay switch device, andFIG. 3illustrates a probe apparatus having a solenoid switch device. Therefore, hereinafter, a relay switch device and a solenoid switch device as examples will be explained.

FIG. 2is a configuration view showing main parts of the probe apparatus depicted inFIG. 1.

As depicted inFIG. 2, a relay switch device181as the switch device18includes a switch181A provided at the second measurement line16, a contact point181B of the switch181A, a coil181C configured to magnetize the contact point181B, a wiring181D configured to connect the coil181C to a power supply (not illustrated), and a controller181E configured to control the coil181C. If the contact point181B is magnetized via the coil181C, the switch181A is brought into electrical contact with the contact point181B as indicated by a dashed dotted line, and the collector electrode of the power device on the chuck top12A is electrically connected to the tester17via the second measurement line16. The switch181A, the contact point181B, and the coil181C are all accommodated in a high-insulation block181F.

One end of the second measurement line16including the relay switch device181is electrically connected to the second conductive film electrode member13B formed on the entire surface of the circumferential surface of the chuck top12A and the other end thereof is electrically connected to the tester17as depicted inFIG. 2. In order to ensure the electrical connection between the second measurement line16and the second conductive film electrode member13B, at a connecting portion between the second measurement line16and the second conductive film electrode member13B, a conductive plate12B is provided in a certain range. The second measurement line16is firmly fixed to this conductive plate12B by a fixing member such as a screw or the like. The relay switch device181is provided at the second measurement line16to be close to the mounting table12as depicted inFIG. 2. The relay switch device181is in an opened state when dynamic characteristics of the power devices are measured, and it is in a closed state when static characteristics of the power devices are measured.

As depicted inFIG. 3, a solenoid switch device182as the switch device18includes a contactor182A electrically connected to an end portion of the second measurement line16, a solenoid182B configured to straightly move the contactor182A, a driving control unit182C configured to magnetize the solenoid182B, and a coil spring182D configured to return the contactor182A to its original position when the magnetization of the solenoid182B is removed. Under the control of the driving control unit182C, the contactor182A is straightly moved back and forth in cooperation with the solenoid182B and the coil spring182D, and a front end of the contactor182A is configured to be attached and detached to/from the second conductive film electrode member13B of the chuck top12A. When static characteristics of the power devices are measured, the contactor182A is in contact with the second conductive film electrode member13B, and the tester17is electrically connected to the second conductive film electrode member13B. Meanwhile, when dynamic characteristics of the power devices are measured, the contactor182A is separated from the second conductive film electrode member13B to separate the second measurement line16from the conductive film electrode13and disconnect the second conductive film electrode member13B from the tester17. Although not illustrated, the solenoid182B includes a plunger, a receiving portion configured to receive the plunger, and a coil configured to move the plunger back and forth. The contactor182A is provided along an axis center of the plunger and is moved back and forth via the plunger.

Hereinafter, an operation of the probe apparatus10in accordance with the present example embodiment will be explained. When electrical characteristics of the power devices are measured, for example, after static characteristics are measured, dynamic characteristics are measured. In order to do so, the switch device18is driven in advance to close an electric path of the second measurement line16and electrically connect the second conductive film electrode member13B of the chuck top12A to the tester17. In this state, the wafer W on which the multiple power devices are formed is unloaded from the loader chamber and then mounted on the chuck top12A of the mounting table12within the prober chamber11. Thereafter, the wafer W is held onto the chuck top12A via the vacuum-attraction unit. Then, the gate electrode and the emitter electrode of the wafer W on the mounting table12are aligned with the multiple probes14A of the probe card14via an alignment device.

Thereafter, by moving the mounting table12to be raised from right below a power device to be measured first, a gate electrode and an emitter electrode of the power device are brought into electrical contact with the multiple probes14A. In this state, if a voltage is applied to the gate electrode of the power device from the tester17via the probe14A, a high current flows from the tester17to the second conductive film electrode member13B of the chuck top12A, i.e. the conductive film electrode13, via the second measurement line16. This current flows from the collector electrode of the power device to the emitter electrode. In this case, static characteristics, such as resistance, of the power device are measured via another probe14A, and the tester17obtains the static characteristics such as resistance based on a result of the measurement. After the static characteristics are measured from the first power device, the mounting table12is moved, and then, static characteristics of a next power device are sequentially measured.

After the static characteristics of the power devices are measured, dynamic characteristics are measured. That is, the switch device18is driven to open the electric path of the second measurement line16and disconnect the tester17from the chuck top12A. In this state, a power device to be measured first is moved to right below the probe card14. Then, when the chuck top12A is raised, a gate electrode and an emitter electrode of the power device are brought into electrical contact with the multiple probes14A of the probe card14, and the first conductive film electrode member13A of the chuck top12A is brought into electrical contact with the multiple conducting pins15A protruding downwardly from the probe card14. Thus, the gate electrode and the emitter electrode of the power device are connected to the tester17via the probes14A, and the collector electrode of the power device is electrically connected to the tester17via the first conductive film electrode member13A of the chuck top12A and the multiple conducting pins15A (first measurement line15).

Then, when a voltage is applied from the tester17to the gate electrode of the power device via the probe14A, a high current flows from the tester17to the conductive film electrode13of the chuck top12A via the first measurement line15(cable15B) and the conducting pins15A. Then, the high current flows to the collector electrode of the power device and then introduced from the emitter electrode to the tester17. As a result, the tester17can measure dynamic characteristics of the power device. In this case, since the second measurement line16is disconnected from the chuck top12A, it is possible to suppress affection of inductance caused by the second measurement line16.

As explained above, in accordance with the present example embodiment, both of static characteristics and dynamic characteristics of the power devices can be measured with the single probe apparatus10, and when dynamic characteristics are measured, the dynamic characteristics of the power devices can be surely measured at a wafer level without being affected by the second measurement line16that measures static characteristics.

The above-described example embodiment is not provided for limitation, and each component can be modified and changed in design as necessary. The switch device provided at the second measurement line16is not limited to the description of the present example embodiment, and any one including a switch device can be appropriately employed.

EXPLANATION OF REFERENCE NUMERALS