JP5345161B2 - Wafer carrier for power device and inspection apparatus using this wafer carrier - Google Patents

Description

The present invention relates to a wafer carrier and the inspection apparatus for a power device, and more particularly, it is possible to realize an electric characteristic inspection of the power device at the wafer level using Uehakyari for power devices, a wafer carrier for power devices And an inspection apparatus using the wafer carrier.

  A conventional inspection apparatus includes, for example, a loader chamber for storing an object to be inspected (for example, a wafer), a prober chamber for inspecting electrical characteristics of the wafer, and a control device. The loader chamber includes a wafer storage unit that stores wafers in cassette units, a wafer transfer mechanism that transfers wafers between the cassette and the prober chamber, and a pre-alignment mechanism that performs wafer pre-alignment during transfer of wafers to the prober chamber. And. The prober chamber includes a movable mounting table on which a wafer is mounted, a probe card having a plurality of probes arranged above the mounting table, and a plurality of electrode pads and a plurality of probes formed on the wafer. An alignment mechanism.

  When inspecting the wafer, the wafer is transferred from the cassette in the loader chamber onto the mounting table in the prober chamber under the control of the control device, and the pre-aligned wafer is mounted on the mounting table. After the alignment, the plurality of devices formed on the wafer are inspected by bringing the plurality of electrode pads and the plurality of probes into contact with each other with a predetermined contact load.

  By the way, in recent years, development of power devices made of silicon carbide (SiC), gallium nitride (GaN) or the like has been activated. These power devices have become practical applications for electric vehicles and hybrid vehicles, and the demand for these devices is expected to increase rapidly, so the development of power devices is an urgent task. . Inspecting the electrical characteristics of power devices in the development stage and post-development power devices, the above inspection apparatuses are also used. In that case, after the power devices are separated from the wafer one by one, an electrical characteristic inspection is performed on the separated power devices. For such inspection, for example, the chip carrier proposed by the present applicant in Patent Document 1 can be used.

  Therefore, the chip carrier proposed by the applicant will be described. For example, as shown in FIG. 5, the chip carrier includes a circular carrier body 1, a storage area 2 that is formed in a matrix shape on the upper surface of the carrier body 1 and that stores a power device, and these storage areas 2 and a rectangular positioning member 3 for positioning the power device in the storage area 2. A plurality of suction holes 4 penetrating the carrier body 1 are formed in the storage area 2.

  However, when a power device is inspected using a chip carrier, a chip carrier in which a plurality of power devices are stored in advance is transported from the wafer storage section of the loader chamber and mounted on the mounting table in the prober chamber after pre-alignment. Put. In the prober chamber, the alignment of the electrode pads of the power device and the plurality of probes is performed using the alignment mechanism, and then the individual power devices are inspected. After the inspection, the chip carrier on the mounting table is attached to the wafer in the loader chamber. Return to the original location in the storage.

  When a chip carrier is used, the power device must be cut from the wafer and stored in each storage area 2 of the chip carrier. Therefore, coupled with the recent increase in demand for power devices, there is an increasing demand for inspection in the wafer state. When inspecting a power device in a wafer state, the wafer is placed on a mounting table in a prober chamber, and a high voltage is applied to each power device to inspect the electrical characteristics of each power device.

JP 2009-128204 A

  However, when the electrical characteristics inspection of the power device is performed in the wafer state, if a defective device is mixed in the wafer, a high abnormal current flows through the defective device and a defective device is damaged. The chuck top of the mounting table may be damaged, and the expensive chuck top may need to be replaced.

The present invention has been made to solve the above-described problems, and can inspect a power device in a wafer state without damaging the chuck top of the mounting table even if a high abnormal current flows through a defective device. It is an object of the present invention to provide a power device wafer carrier and an inspection apparatus using the wafer carrier capable of inspecting electrical characteristics of the power device.

The wafer carrier according to claim 1 of the present invention mounts the mounting table of the inspection apparatus to hold the wafer on which the plurality of power devices are formed when the electrical characteristics inspection of the power device is performed at the wafer level. a wafer carrier that is used to adsorb fixed on the surface, and the carrier body, a resin film peelably bonded on the entire upper surface of the carrier body, as the mounting surface of the wafer on the upper surface of the resin film A conductive metal film formed by laminating a plurality of metal thin films, a plate member bonded to the entire lower surface of the carrier body, a vacuum suction groove formed on the mounting surface of the wafer, and a lower end And a suction hole that opens in the vacuum suction groove of the mounting table and has an upper end that opens in the vacuum suction groove on the mounting surface of the wafer .

  According to a second aspect of the present invention, there is provided the wafer carrier according to the first aspect, wherein the conductive metal film is formed larger in diameter than the outer periphery of the wafer. .

A wafer carrier according to claim 3 of the present invention is the wafer carrier according to claim 11 or 2 , wherein the conductive metal film is deposited on a resin film. .

A wafer carrier according to claim 4 of the present invention is the wafer carrier according to any one of claims 1 to 3 , wherein the carrier body is formed of silicon or glass. Is.

According to a fifth aspect of the present invention, there is provided an inspection apparatus in which a wafer carrier for holding a wafer on which a plurality of power devices are formed is mounted by adsorbing and fixing when inspecting the plurality of power devices. A mounting table, a probe card having a plurality of probes arranged above the mounting table, an alignment mechanism for aligning the plurality of probes and the plurality of electrodes of the wafer, and the plurality of probes. An inspection apparatus for performing electrical characteristics of the plurality of power devices by a four-terminal Kelvin measurement method using two pairs and four pieces, wherein the wafer carrier can be peeled from the carrier main body and the entire upper surface of the carrier main body. A bonded resin film, a conductive metal film formed by laminating a plurality of metal thin films on the upper surface of the resin film as a mounting surface of the wafer, and A plate member bonded to the entire lower surface of the carrier body, a vacuum suction groove formed on the mounting surface of the wafer, a lower end opened in the vacuum suction groove of the mounting table, and an upper end of the wafer A suction hole that opens in a vacuum suction groove on the mounting surface, and the mounting table is spaced apart from the suction hole in addition to the vacuum suction groove in which the suction hole opens. A vacuum suction groove formed to suck the wafer carrier is provided at a position.

According to the present invention, the power device can be inspected in the wafer state, and even if a high abnormal current flows through the defective device, the conductive metal film of the wafer carrier is damaged , and the chuck top of the mounting table is damaged. providing an inspection apparatus using an electrical property test can be performed, moreover wafer carrier and the wafer carrier for power devices that can be used repeatedly replace damaged conductive metal film without power device that Can do.

It is a key map showing one embodiment of an inspection device of the present invention. It is a top view which shows the wafer carrier of this embodiment using the inspection apparatus shown in FIG. It is sectional drawing which shows typically the relationship between the mounting base of the inspection apparatus shown in FIG. 1, the wafer carrier mounted on it, and a wafer. It is a flowchart which shows the procedure of one Embodiment of the test | inspection method of this invention using the test | inspection apparatus shown in FIG. It is a plane which shows the chip carrier used for the inspection method of the conventional power device.

An embodiment of the present invention will be described with reference to FIGS.
First, an inspection apparatus to which the wafer carrier of this embodiment is applied will be described. As shown in FIG. 1, for example, the inspection apparatus 10 used in the present embodiment horizontally moves the mounting table 11 on which the wafer W held by the wafer carrier 20 of the present embodiment is mounted, and the mounting table 11. Drive mechanism 12 that moves in the vertical direction and the vertical direction, probe card 13 having a plurality of probes 13A arranged above mounting table 11, a plurality of probes 13A, and a plurality of electrodes of wafer W on wafer carrier 20 An alignment mechanism 14 that performs alignment and a control device 15 that controls each of these devices are provided, and the electrical characteristics of the wafer W are inspected under the control of the control device 15. In FIG. 1, 13B is a card holder integrated with the probe card 13, and the probe card 13 is fixed to a head plate 16 that forms the upper surface of the prober chamber via the card holder 13B.

  As shown in FIG. 3, a plurality of suction grooves 11A are concentrically formed on the upper surface of the mounting table 11, and these suction grooves 11A communicate with each other by grooves (not shown) formed in the radial direction. . Further, an exhaust passage 11B connected to a vacuum device is opened in the suction groove 11A, and the wafer carrier 20 is vacuum-sucked in the suction groove 11A by exhausting from the suction groove 11A and the exhaust passage 11B by the vacuum device. . A part of the suction grooves 11 </ b> A communicates with a vacuum suction groove of the wafer carrier 20.

  In addition, as shown in FIG. 1, the alignment mechanism 14 is attached to the side of the mounting table 11 and has a first CCD camera 14A that images the plurality of probes 13A, and an alignment bridge 14B and a wafer on the mounting table 11. A second CCD camera 14C for imaging W; and an image processing device 14D for image processing based on imaging signals from the first and second CCD cameras 14A and 14C, and imaging from the first and second CCD cameras 14A and 14C. Based on the signal, the plurality of probes 13A and the plurality of electrodes of the wafer W are aligned.

  Thus, as shown in FIG. 1, the wafer carrier 20 of the present embodiment is placed on the mounting table 11 while holding the wafer on which the plurality of power devices are formed, and the electrical power of the plurality of power devices is determined. The characteristic inspection can be performed in the wafer state, and is stored in, for example, a buffer table provided in the loader chamber. For example, as shown in FIG. 2, the wafer carrier 20 is formed in a circular shape having a diameter larger than the outer diameter of the wafer W, and is formed to hold, for example, three types of wafers of 4 inches, 6 inches, and 8 inches. Yes. On the upper surface of the wafer carrier 20, for example, three vacuum suction grooves (hereinafter referred to as "suction grooves") 20A are formed concentrically. In these suction grooves 20 </ b> A, suction holes 20 </ b> B that communicate with the concentric suction grooves 11 </ b> A of the mounting table 11 and penetrate the wafer carrier 20 are opened as shown in FIG. 3. When the wafer is an 8-inch wafer, the wafer is sucked by all the suction grooves 20A, and when the wafer is a 4-inch wafer, the wafer is sucked by the suction groove 20A having the smallest diameter.

  Accordingly, the vacuum device is driven to exhaust from the exhaust passage 11 </ b> B of the mounting table 11, the wafer carrier 20 is vacuum-adsorbed onto the mounting table 11, and the wafer carrier 20 is fixed onto the mounting table 11. 2 and 3, reference numeral 20 </ b> C denotes a through hole through which the elevating pins provided on the mounting table 11 pass, and when the wafer W is transferred on the wafer carrier 20, the elevating pins move from the through hole 20 </ b> C to the upper surface of the wafer carrier 20. Protruding.

  For example, as shown in FIGS. 2 and 3, the wafer carrier 20 includes a carrier body 21, a resin film 22 formed on the entire upper surface of the carrier body 21, and a conductive metal film formed on the entire upper surface of the resin film 22. 23 and a plate member 24 bonded to the entire lower surface of the carrier body 21, and the conductive metal film 23 is configured to function as a collector electrode by being in electrical contact with the collector electrode C of the wafer W. Yes.

  Each layer of the wafer carrier 20 is configured as follows. The carrier body 21 is made of, for example, silicon or glass, and the resin film 22 is made of, for example, a polyimide resin. The resin layer 22 is bonded to the carrier body 21 via an adhesive, and can be replaced together with the resin film 22 when the conductive metal film 23 is damaged. As shown in FIG. 3, the conductive metal film 23 includes a copper thin film layer 23A deposited on the upper surface of the resin film 22, a nickel thin film layer 23B deposited on the entire upper surface of the copper thin film layer 23A, and a nickel thin film. And a gold thin film layer 23C deposited on the upper surface of the layer 23B. These thin film layers are all formed by, for example, plating.

  A power device such as an IGBT is formed on the wafer W to which the wafer carrier 20 is applied. The IGBT has a gate electrode, an emitter electrode, and a collector electrode. In FIG. 3, only the emitter electrode E formed on the upper surface of the wafer W and the collector electrode C formed on the lower surface of the wafer are shown. The electrical characteristic inspection of these power devices is performed by a four-terminal Kelvin measurement method using two pairs and four probes as shown in FIG.

A pair of the probes 13A, together with the source power supply 30A is connected to the 13A, another pair of probes 13A, the 13A are connected to the monitor 30B. On the source power supply 30A side, one probe 13A is in electrical contact with the emitter electrode of the power device, and the other probe 13A is in electrical contact with the conductive metal film 23 of the wafer carrier 20. On the monitor 30B side, one probe 13A is in electrical contact with the emitter electrode E of the power device, and the other probe 13A is in electrical contact with the conductive metal film 23 of the wafer carrier 20. Therefore, a current is passed from the source power source 30A to the power device, and the voltage between the power devices is detected by the monitor 30B, thereby checking the electrical characteristics of the power device. Further, the probe 13A that contacts the wafer W side can be switched each time a power device is inspected one by one or plural by a switch mechanism (not shown).

  Next, the inspection method of this embodiment will be described with reference to FIG. First, in the loader chamber, the wafer transfer mechanism unloads the wafer carrier 20 from the buffer table and delivers it to a pre-alignment mechanism (not shown), where the wafer carrier 20 is pre-aligned (step S1). Thereafter, when the wafer carrier mechanism places the wafer carrier 20 on the placement table 11 in the prober chamber from the pre-alignment mechanism (step S2), the wafer carrier 20 is fixed on the placement table 11 by vacuum suction. At this time, since the wafer carrier 20 is after pre-alignment, the center thereof coincides with the center of the mounting surface of the mounting table 11.

  Thereafter, when the wafer transfer mechanism carries the wafer W out of the cassette (not shown), the pre-alignment mechanism performs pre-alignment of the wafer W in the same manner as the wafer carrier 20 (step S3). The wafer transfer mechanism places the pre-aligned wafer W on the wafer carrier 20 fixed on the mounting table 11 (step S4). Also at this time, the center of the wafer W coincides with the centers of the mounting table 11 and the wafer carrier 20. At this time, the wafer carrier 20 vacuum-sucks and fixes the wafer W via the suction groove 20.

  Subsequently, after the mounting table 11 and the alignment mechanism 14 cooperate to perform the alignment of the wafer W (step S5), the mounting table 11 moves in the horizontal direction and transports the wafer W directly below the probe card 13. Ascending from the position, the wafer W and the plurality of probes 13A are brought into electrical contact collectively. Then, a plurality of power devices are inspected one or more at a time (step S6). Thereafter, it is determined whether or not all power devices have been inspected. If there is an uninspected power device, the process returns to step S6 to inspect the next power device. Steps S6 and S7 are repeated, and if it is determined in step 7 that all power devices have been inspected, the wafer W is returned to the original location of the cassette via the wafer transfer mechanism (step S8).

  Next, it is determined whether or not there is a next wafer W to be inspected in the cassette (step S9). If it is determined that there is a next wafer W to be inspected, the process returns to step S3 to The inspection is performed on all the power devices on the wafer W by following the procedure from step S3 to step S7. When the inspection of the last wafer W is completed, it is determined in step S9 that the inspection of all the wafers W has been completed, and the inspection of the wafers W is completed.

  While the inspection of the wafer W is repeated, an abnormal current flows in the inspection of a defective device of any one of the wafers W, and the conductive metal film 23 of the wafer carrier 20 may be burnt or damaged. In that case, after the inspection of other power devices in the wafer W is completed, the wafer carrier 20 is replaced and the inspection is continued using the spare wafer carrier 20. The damaged wafer carrier 20 peels off the resin film 22 from the carrier main body 21 and attaches a substitute resin film 23 to the carrier main body 21 to repair the wafer carrier 20.

  As described above, according to the present embodiment, when inspecting the power device of the wafer W, the wafer carrier 20 holding the wafer W is set on the mounting table 11 in advance, and the wafer W is mounted on the wafer carrier 20. Therefore, the electrical property inspection of the wafer W can be performed in the wafer state. In addition, even if a defective device is mixed in the wafer W and an abnormal current is generated during the inspection of the defective device, the conductive metal film 23 of the wafer carrier 20 is only sacrificed and the mounting table 11 is prevented from being damaged. can do.

  Moreover, according to this embodiment, since the resin film 22 to which the conductive metal film 23 is applied can be peeled from the carrier body 21, the conductive metal film 23 is damaged by an abnormal current or the like. Even if there is, the wafer carrier 20 can be regenerated by replacement. The wafer carrier 20 of the present embodiment can also be used for transporting thin wafers and TAIKO wafers depending on the specifications.

  In addition, this invention is not restrict | limited at all to the said embodiment, The design change of the component of this invention can be carried out suitably. For example, although the conductive metal film 23 has a three-layer structure of a copper thin film 23A, a nickel thin film 23B, and a gold thin film 23C, a layer structure other than the three-layer structure can be adopted using other metals.

DESCRIPTION OF SYMBOLS 10 Inspection apparatus 11 Mounting base 13 Probe card 13A Probe 14 Alignment mechanism 15 Control apparatus 20 Wafer carrier 20A Adsorption groove 20B Adsorption hole 21 Carrier body 22 Resin film 23 Conductive metal film 23A Copper thin film 23B Nickel foil film 23C Gold thin film W Wafer

Claims (5)

When inspecting electrical characteristics of the power device at a wafer level, in adsorbed and fixed to the wafer carrier that is used on the mounting surface of the mounting table of the test apparatus to hold the wafer in which a plurality of power devices are formed There,
The carrier body,
A resin film that is releasably bonded to the entire upper surface of the carrier body ;
A conductive metal film formed by laminating a plurality of metal thin films on the upper surface of the resin film as a mounting surface of the wafer;
A plate member bonded to the entire lower surface of the carrier body;
A groove for vacuum suction formed on the mounting surface of the wafer ;
A wafer carrier comprising: a suction hole having a lower end opened in a vacuum suction groove of the mounting table and an upper end opened in a vacuum suction groove on the wafer mounting surface .   The wafer carrier according to claim 1, wherein the conductive metal film is formed to have a larger diameter than the outer periphery of the wafer. The wafer carrier according to claim 1 or 2 , wherein the conductive metal film is attached to a resin film. The wafer carrier according to claim 1, wherein the carrier body is made of silicon or glass. A movable mounting table for mounting a wafer carrier for holding a wafer on which a plurality of power devices are formed by suction and fixing when inspecting the plurality of power devices, and a position above the mounting table. A probe card having a plurality of probes, an alignment mechanism for aligning the plurality of probes and the plurality of electrodes of the wafer, and a four-terminal Kelvin measurement method using two or four pairs of the plurality of probes. An inspection apparatus for performing electrical characteristics of the plurality of power devices ,
The wafer carrier is
The carrier body,
A resin film that is releasably bonded to the entire upper surface of the carrier body;
A conductive metal film formed by laminating a plurality of metal thin films on the upper surface of the resin film as a mounting surface of the wafer;
A plate member bonded to the entire lower surface of the carrier body;
A groove for vacuum suction formed on the mounting surface of the wafer;
A suction hole having a lower end opened in the vacuum suction groove of the mounting table and an upper end opened in the vacuum suction groove of the mounting surface of the wafer, and
The table above is
In addition to the vacuum suction groove in which the suction hole is opened , an inspection apparatus comprising a vacuum suction groove formed to suck the wafer carrier at a position spaced from the suction hole .

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