Probe apparatus

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.

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

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

As depicted in FIG. 4 , the prober chamber includes a movable mounting table 1 configured to mount a wafer W thereon, and a probe card 2 provided above the mounting table 1 . On a surface of the mounting table 1 , a conductive film electrode 3 (shown as a thick line in FIG. 4 ) made of a conductive metal such as gold or the like is formed. This conductive film electrode 3 is electrically connected to a tester 5 via a measurement line 4 (for example, cable).

If the probe apparatus depicted in FIG. 4 measures static characteristics of a power device at a wafer level, when the wafer W is mounted on the mounting table 1 , a collector electrode of the power device on a lower surface of the wafer W is brought into electrical contact with the conductive film electrode 3 of the mounting table 1 . When the probe card 2 is brought into contact with this wafer W, a gate electrode and an emitter electrode of the power device are electrically connected to multiple probes 2 A. In this state, if a voltage is applied from the probe 2 A to the gate electrode of the power device, a high current flows from the tester 5 to the measurement line 4 , the conductive film electrode 3 , 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 probes 2 A. Further, in FIG. 4 , the probe card 2 is fixed to a head plate 6 via 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 in FIG. 4 (see Patent Document 1). That is, in the probe apparatus described in Patent Document 1, the same measurement line as the measurement line 4 depicted in FIG. 4 is 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.

Patent Document 1: Japanese Patent Laid-open Publication No. 2012-058225

Problems to be Solved by the Invention

However, in the probe apparatus depicted in FIG. 4 , the conductive film electrode 3 of the mounting table 1 is continuously connected to the tester 5 through the measurement line 4 . Therefore, in the probe apparatus described in Patent Document 1 in which the same measurement line as the measurement line 4 is provided, it has been found that when dynamic characteristics, such as a switching characteristic, of a power device are measured, inductance of the measurement line 4 serves 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.

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

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

FIG. 3 is a configuration view showing main parts of a probe apparatus in accordance with another example embodiment.

FIG. 4 is a conceptual diagram showing an example of a conventional probe apparatus.

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

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

A probe apparatus 10 in accordance with the present example embodiment is configured to receive a wafer W in a prober chamber 11 from 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 chamber 11 , as depicted in, for example, FIG. 1 .

As depicted in FIG. 1 , within the prober chamber 11 , a mounting table 12 configured 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 top 12 A of the mounting table 12 and the entire surface of a circumferential surface thereof, a conductive film electrode 13 (shown as a thick line in FIG. 1 ) made of a conductive metal such as gold or the like is formed as a collector electrode. The chuck top 12 A includes a vacuum-attraction unit configured to vacuum-attract the wafer W on the mounting surface of the chuck top 12 A. Further, the mounting table 12 accommodates 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 electrode 13 includes a first conductive film electrode member 13 A formed on the entire surface of the mounting surface of the chuck top 12 A and a second conductive film electrode member 13 B formed on the entire surface of an outer peripheral surface of the chuck top 12 A.

Above the mounting table 12 , as depicted in FIG. 1 , a probe card 14 provided with a card holder is fixed to a head plate 11 A, which forms an upper surface of the prober chamber 11 , via a clamp mechanism (not illustrated). At a central portion on a lower surface of the probe card 14 , multiple probes 14 A are provided. These probes 14 A 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 apparatus 10 in accordance with the present example embodiment includes a first measurement line 15 that measures dynamic characteristics of the power devices and a second measurement line 16 that measures static characteristics of the power devices as described below.

As depicted in FIG. 1 , the first measurement line 15 includes, for example, multiple conducting pins 15 A arranged at preset intervals along an outer periphery of the lower surface of the probe card 14 in a circumferential direction thereof, and a cable 15 B electrically connected to the multiple conducting pins 15 A via a conductive member (not illustrated). The other end of the cable 15 B is electrically connected to a tester 17 . The conductive member configured to connect the conducting pins 15 A and the cable 15 B is provided on the lower surface of the probe card 14 . The multiple conducting pins 15 A are configured to be electrically attached and detached to/from the first conductive film electrode member 13 A by moving the chuck top 12 A up and down through an elevation driving device (not illustrated) embedded in the mounting table 12 . Like, for example, pogo pins, the conducting pins 15 A have elasticity and are configured to be elastically brought into contact with the first conductive film electrode member 13 A. These conducting pins 15 A may be desirably formed on multiple places at preset intervals along the outer periphery of the probe card 14 , but may be formed on a single place.

When dynamic characteristics of the power devices are measured, the chuck top 12 A of the mounting table 12 is raised by a certain amount. Thus, the first conductive film electrode member 13 A (collector electrode) of the chuck top 12 A is brought into electrical contact with the conducting pins 15 A, and the tester 17 is electrically connected to the conductive film electrode (collector electrode) 13 of the chuck top 12 A via the first measurement line 15 . Further, the multiple probes 14 A 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 top 12 A. In this state, if a preset voltage is applied from the tester 17 to the gate electrode of the power device, a high current flows from the tester 17 to the first conductive film electrode member 13 A of the chuck top 12 A via the first measurement line 15 , and this current flows from the collector electrode of the power device to the tester 17 through the emitter electrode. Since the first measurement line 15 has 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) 16 electrically connects the tester 17 to the second conductive film electrode member 13 B and is configured to measure static characteristics of the power devices. Desirably, this measurement line 16 may 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 line 16 includes a switch device 18 configured to open and close an electric path between the second conductive film electrode member 13 B and the tester 17 . This switch device 18 separates the second measurement line 16 from the chuck top 12 A by opening a switch to suppress affection of the inductance of the second measurement line 16 when dynamic characteristics of the power devices are measured as described above.

Examples of the switch device 18 may include, for example, a relay switch device, a solenoid switch device, and a cylinder switch device. Depending on a kind of the switch device 18 , a connection example between the second measurement line 16 and the second conductive film electrode member 13 B varies as depicted in FIG. 2 and FIG. 3 . FIG. 2 illustrates a probe apparatus having a relay switch device, and FIG. 3 illustrates 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. 2 is a configuration view showing main parts of the probe apparatus depicted in FIG. 1 .

As depicted in FIG. 2 , a relay switch device 181 as the switch device 18 includes a switch 181 A provided at the second measurement line 16 , a contact point 181 B of the switch 181 A, a coil 181 C configured to magnetize the contact point 181 B, a wiring 181 D configured to connect the coil 181 C to a power supply (not illustrated), and a controller 181 E configured to control the coil 181 C. If the contact point 181 B is magnetized via the coil 181 C, the switch 181 A is brought into electrical contact with the contact point 181 B as indicated by a dashed dotted line, and the collector electrode of the power device on the chuck top 12 A is electrically connected to the tester 17 via the second measurement line 16 . The switch 181 A, the contact point 181 B, and the coil 181 C are all accommodated in a high-insulation block 181 F.

One end of the second measurement line 16 including the relay switch device 181 is electrically connected to the second conductive film electrode member 13 B formed on the entire surface of the circumferential surface of the chuck top 12 A and the other end thereof is electrically connected to the tester 17 as depicted in FIG. 2 . In order to ensure the electrical connection between the second measurement line 16 and the second conductive film electrode member 13 B, at a connecting portion between the second measurement line 16 and the second conductive film electrode member 13 B, a conductive plate 12 B is provided in a certain range. The second measurement line 16 is firmly fixed to this conductive plate 12 B by a fixing member such as a screw or the like. The relay switch device 181 is provided at the second measurement line 16 to be close to the mounting table 12 as depicted in FIG. 2 . The relay switch device 181 is 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 in FIG. 3 , a solenoid switch device 182 as the switch device 18 includes a contactor 182 A electrically connected to an end portion of the second measurement line 16 , a solenoid 182 B configured to straightly move the contactor 182 A, a driving control unit 182 C configured to magnetize the solenoid 182 B, and a coil spring 182 D configured to return the contactor 182 A to its original position when the magnetization of the solenoid 182 B is removed. Under the control of the driving control unit 182 C, the contactor 182 A is straightly moved back and forth in cooperation with the solenoid 182 B and the coil spring 182 D, and a front end of the contactor 182 A is configured to be attached and detached to/from the second conductive film electrode member 13 B of the chuck top 12 A. When static characteristics of the power devices are measured, the contactor 182 A is in contact with the second conductive film electrode member 13 B, and the tester 17 is electrically connected to the second conductive film electrode member 13 B. Meanwhile, when dynamic characteristics of the power devices are measured, the contactor 182 A is separated from the second conductive film electrode member 13 B to separate the second measurement line 16 from the conductive film electrode 13 and disconnect the second conductive film electrode member 13 B from the tester 17 . Although not illustrated, the solenoid 182 B includes a plunger, a receiving portion configured to receive the plunger, and a coil configured to move the plunger back and forth. The contactor 182 A is provided along an axis center of the plunger and is moved back and forth via the plunger.

Hereinafter, an operation of the probe apparatus 10 in 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 device 18 is driven in advance to close an electric path of the second measurement line 16 and electrically connect the second conductive film electrode member 13 B of the chuck top 12 A to the tester 17 . 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 top 12 A of the mounting table 12 within the prober chamber 11 . Thereafter, the wafer W is held onto the chuck top 12 A via the vacuum-attraction unit. Then, the gate electrode and the emitter electrode of the wafer W on the mounting table 12 are aligned with the multiple probes 14 A of the probe card 14 via an alignment device.

Thereafter, by moving the mounting table 12 to 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 probes 14 A. In this state, if a voltage is applied to the gate electrode of the power device from the tester 17 via the probe 14 A, a high current flows from the tester 17 to the second conductive film electrode member 13 B of the chuck top 12 A, i.e. the conductive film electrode 13 , via the second measurement line 16 . 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 probe 14 A, and the tester 17 obtains 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 table 12 is 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 device 18 is driven to open the electric path of the second measurement line 16 and disconnect the tester 17 from the chuck top 12 A. In this state, a power device to be measured first is moved to right below the probe card 14 . Then, when the chuck top 12 A is raised, a gate electrode and an emitter electrode of the power device are brought into electrical contact with the multiple probes 14 A of the probe card 14 , and the first conductive film electrode member 13 A of the chuck top 12 A is brought into electrical contact with the multiple conducting pins 15 A protruding downwardly from the probe card 14 . Thus, the gate electrode and the emitter electrode of the power device are connected to the tester 17 via the probes 14 A, and the collector electrode of the power device is electrically connected to the tester 17 via the first conductive film electrode member 13 A of the chuck top 12 A and the multiple conducting pins 15 A (first measurement line 15 ).

Then, when a voltage is applied from the tester 17 to the gate electrode of the power device via the probe 14 A, a high current flows from the tester 17 to the conductive film electrode 13 of the chuck top 12 A via the first measurement line 15 (cable 15 B) and the conducting pins 15 A. Then, the high current flows to the collector electrode of the power device and then introduced from the emitter electrode to the tester 17 . As a result, the tester 17 can measure dynamic characteristics of the power device. In this case, since the second measurement line 16 is disconnected from the chuck top 12 A, it is possible to suppress affection of inductance caused by the second measurement line 16 .

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 apparatus 10 , 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 line 16 that 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 line 16 is not limited to the description of the present example embodiment, and any one including a switch device can be appropriately employed.

10 : Probe apparatus

12 : Mounting table

12 A: Chuck top

14 : Probe card

14 A: Probe

15 : First measurement line

15 A: Conducting pins (Conductors)

16 : Second measurement line

17 : Tester

18 : Switch device

181 : Relay switch device

182 : Solenoid switch device

W: Wafer