Transfer mechanism for target object to be inspected

A transfer mechanism for a target object includes at least two insulating wire materials disposed spaced from each other to transverse a mounting table, at least two pairs of supporting bodies horizontally disposed at outsides of the mounting table, for stretching said at least two wire materials in parallel with a mounting surface of the mounting table, and at least two grooves formed on the mounting surface of the mounting table to respectively receive therein said at least two wire materials by said at least two pairs of supporting bodies. The transfer mechanism further includes a first elevation driving mechanism for vertically moving said wire materials between said grooves and above of the mounting surface through said pairs of supporting bodies, wherein the target object is transferred between a carrying mechanism and the mounting table through said at least two wire materials.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No. 2008-172577, filed on Jul. 1, 2008, the entire contents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a transfer mechanism for a target object to be inspected which is used for a probe apparatus for inspecting electrical characteristics of the target object such as a semiconductor wafer or the like; and, more particularly, to a transfer mechanism for the target object which can improve reliability of inspection.

BACKGROUND OF THE INVENTION

A conventional probe apparatus includes a loader chamber1and a prober chamber2arranged adjacent to each other as shown in, e.g.,FIG. 6. The loader chamber1includes a cassette receiving part for receiving a cassette containing a plurality of semiconductor wafers W therein, a wafer carrying mechanism for transferring the semiconductor wafers W taken out of the cassette one by one, and a pre-alignment mechanism for pre-aligning the semiconductor wafer W while transferring the semiconductor wafer W by the wafer carrying mechanism. The prober chamber2has a mounting table3which is movable in X, Y, Z and θ directions while mounting thereon a semiconductor wafer W, a probe card4having a plurality of probes4A to be brought into electrical contact with electrode pads of devices formed on the semiconductor wafer W mounted on the mounting table3, a fixing mechanism5for fixing the probe card4through a card holder (not shown), and a connecting ring6for electrically connecting the probe card4and a test head T.

The conventional probe apparatus is configured to inspect electrical characteristics of each of the devices by transmitting and receiving test signals between a tester (not shown) and the electrode pads of each of the devices formed on the semiconductor wafer W via the test head T, the connecting ring6and the probe card4.

Further, inFIG. 6, reference numeral ‘7’ indicates an alignment mechanism for performing position-alignment of the semiconductor wafer W and the probe card4in cooperation with the mounting table3; reference numerals ‘7A’ and ‘7B’ represent an upper camera and a lower camera, respectively; and reference numeral ‘8’ indicates a head plate to which the fixing mechanism5of the probe card4is attached.

Further, as illustrated in, e.g.,FIG. 7, the mounting table3has a mounting table main body3A, a mounting body3B movable vertically with respect to the mounting table main body3A, and a transfer mechanism for the semiconductor wafer W.

The transfer mechanism has through holes formed at three locations spaced apart from each other at regular intervals in a circumferential direction on the mounting body3B and three elevating pins3C movable vertically in the through holes. While the semiconductor wafer W is transferred by the wafer carrying mechanism9, the three elevating pins3C protrude upward from the mounting surface of the mounting body3B to be in ready for receiving the semiconductor wafer W.

Next, the wafer carrying mechanism9is lowered, and the semiconductor wafer W is delivered to the three elevating pins3C. Thereafter, the wafer carrying mechanism9is retreated from the mounting body3B into the loader chamber1. The three elevating pins3C being received the semiconductor wafer W are lowered and retreated into the mounting body3B and the semiconductor wafer W is mounted on the mounting body3B. The semiconductor wafer W is held on the mounting surface of the mounting body3B by vacuum adsorption. Next, the alignment mechanism7performs alignment of the semiconductor wafer W in cooperation with the mounting table3, and the semiconductor wafer W on the mounting table3is brought into electrical contact with the probes4A of the probe card4, thereby inspecting electrical characteristics of the semiconductor wafer W.

However, in the conventional transfer mechanism for a semiconductor wafer W, the through holes which allow the elevating pins3C to pass therethrough are formed at three locations, so that leakage of electromagnetic waves from the lower portions of the through holes toward the semiconductor wafer W can be occurred. This causes electrical noise during inspection of devices formed on the semiconductor wafer W, which may adversely affect the inspection result. Further, in the case that devices generate heat, the semiconductor wafer W can be cooled to a predetermined inspection temperature by a temperature control mechanism provided at the mounting table3. However, it is not possible to cool down devices formed at portions corresponding to the three through holes. Accordingly, heat spots may be generated, and the inspection may not be performed at the required inspection temperature. Moreover, in the case of devices to be inspected by applying a high voltage, abnormal discharge may occur in the through holes during the inspection.

The above-described elevating pins have been widely used conventionally. For example, elevating pins described in Japanese Patent Laid-open Application No. 2002-64132 and correspond U.S. Pat. No. 6,739,208 are different from those shown inFIG. 7in that they are used to transfer a curved semiconductor wafer. These elevating pins are made to project upward from the mounting table with different projection amounts to incline the curved semiconductor wafer. This makes is possible to reliably transfer the semiconductor wafer W between the wafer carrying mechanism and the mounting table. In addition, elevating pins described in Japanese Patent Laid-open Application No. 2007-288101 are substantially the same as those illustrated inFIG. 7which are widely used in general.

SUMMARY OF THE INVENTION

In view of the above, the present invention provides a transfer mechanism for a target object to be inspected which can perform highly reliable inspection with high accuracy without generating electrical noise, heat spots or the like.

In accordance with an aspect of the present invention, there is provided a transfer mechanism for a target object to be inspected which transfers the target object between a carrying mechanism and a mounting table in order to inspect electrical characteristics of the target object mounted on the mounting table of which temperature is controllable.

The transfer mechanism includes: at least two insulating wire materials disposed spaced apart from each other to transverse the mounting table; at least two pairs of supporting bodies disposed at outsides of the mounting table in a horizontal direction thereof, for stretching respective said at least two wire materials in parallel with a mounting surface of the mounting table; at least two grooves formed on the mounting surface of the mounting table to respectively receive therein said at least two wire materials stretched by said at least two pairs of supporting bodies; and a first elevation driving mechanism for vertically moving said at least two wire materials between said at least two grooves and above of the mounting surface through said at least two pairs of supporting bodies, wherein target object is transferred between the carrying mechanism and the mounting table through said at least two wire materials.

Further, the mounting table may include a mounting table main body, a mounting body movable vertically with respect to the mounting table main body, and a second elevation driving mechanism also serving as the first elevation driving mechanism for elevating the mounting body, wherein the mounting body may have stopper plates to bring into contact with lower ends of the respective supporting bodies and elevation guide mechanisms for guiding vertical movement of the respective supporting bodies.

The mounting table may also include a mounting table main body and a mounting body provided above the mounting table main body, and wherein the mounting body has at least two pairs of cylinder mechanisms as the first elevation driving mechanism, each pair connected with lower ends of said at least two pairs of supporting bodies and elevation guide mechanisms for guiding vertical movement of said at least two pairs of supporting bodies, respectively.

Each pair of the supporting bodies may have therein respective spring member connected with opposite end of each of the wire materials, and the spring members may apply tensile force to the respective wire materials.

In accordance with the present invention, it is possible to provide a transfer mechanism for a target object to be inspected which can perform highly reliable inspection with high accuracy without generating electrical noise, heat spots or the like.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present invention will be described with reference toFIGS. 1A to 5Cwhich form a part hereof.

First Embodiment

A transfer mechanism for a target object to be inspected (hereinafter, simply referred to as a “transfer mechanism”) in accordance with the first embodiment is used to transfer the target object (e.g., a semiconductor wafer) between a carrying mechanism for carrying the target object (hereinafter, referred to as a “wafer carrying mechanism”) which is provided in a loader chamber of a probe apparatus and a mounting table in a prober chamber. The loader chamber has a conventional configuration and the transfer mechanism is provided in the prober chamber. As in the conventional case, the prober chamber includes a mounting table capable of moving in X, Y, Z and θ directions, a probe card having a plurality of probes, an alignment mechanism and a control unit. After the semiconductor wafer mounted on the mounting table and the probe card are aligned under the control of the control unit, the semiconductor wafer is brought into electrical contact with the probe card, thereby inspecting electrical characteristics of the semiconductor wafer.

A transfer mechanism of the present embodiment is assembled to a mounting table20for mounting thereon the semiconductor wafer W, as illustrated in, e.g.,FIGS. 1A and 1C. The mounting table20includes a mounting table main body21, a mounting body22movable vertically with respect to the mounting table main body21, and elevation driving mechanism23for vertically moving the mounting body22under the control of the control unit. The mounting table20is disposed on an XY table30, and is configured to move in X and Y directions through the XY table30.

The elevation driving mechanism23includes a ball screw having an upper end connected with the mounting body22, a motor for driving the ball screw and a nut member screw-coupled with the ball screw, and the mounting body22is configured to move vertically with respect to the mounting table main body21via the elevation driving mechanism23. Moreover, the mounting body22has a temperature control mechanism, and is configured to heat and cool the semiconductor wafer to a predetermined inspection temperature.

Besides, as shown inFIGS. 1A and 1C, the transfer mechanism10includes: two insulating and heat-resistant wire materials11(e.g., zylon: registered trademark of TOYOBO CO., LTD.) spaced apart from each other by a distance on the mounting table20, more specifically on the mounting body22, so as to transverse the mounting body22; two pairs of supporting bodies12provided at outside of the mounting body22in the horizontal direction thereof, for stretching the wire materials11in parallel with the mounting surface of the mounting body22; two grooves13formed on the mounting surface of the mounting body22to receive therein the respective wire materials11stretched by the supporting bodies12, and the elevation driving mechanism23for vertically moving up the wire materials11from the grooves13on the mounting surface to above the mounting body22and moving down the wire materials11into the grooves13.

When the elevation driving mechanism23is driven under the control of the control unit, the two wire materials11move vertically through the supporting bodies12and elevation guide mechanisms15, so that the semiconductor wafer W (seeFIGS. 3A and 3B) is transferred between a wafer carrying mechanism40(seeFIGS. 3A and 3B) and the mounting body22. In the present embodiment, as for the elevation driving mechanism23of the transfer mechanism10which is referred to as a first elevation driving mechanism, the elevation driving mechanism23of the mounting body22, which is referred to as a second elevation driving mechanism, is used. That is, the second elevation driving mechanism for vertically moving the mounting body22serves as the first elevation driving mechanism. Therefore, in the present embodiment, the second elevation driving mechanism will be simply described as the elevation driving mechanism23.

Further, in the present embodiment, the two wire materials11are provided instead of the conventional elevating pins and the two grooves13for receiving therein the two wire materials11are formed instead of the through holes where the elevating pins are received and moved vertically therethrough. The absence of the through holes makes it possible to prevent the conventional problems such as the leakage of electromagnetic waves from the bottom surface of the mounting body22toward the mounting surface, the generation of heat spots and the occurrence of discharge between the elevation pins and the through holes.

In other words, the two wire materials11are generally provided inside the two grooves13which are spaced apart from each other so as to transverse the mounting surface of the mounting body22. The wire materials11are respectively connected with the two pairs of supporting bodies12having both ends disposed to have the mounting body22therebetween, and move vertically between the inside of the grooves13and above of the mounting surface of the mounting body22while being stretched by the two pairs of supporting bodies12.

As shown inFIGS. 1A and 1C, the two pairs of supporting bodies13are vertically movably attached to the fixed members14fixed to a periphery of a bottom surface of the mounting body22. The fixed members14include horizontal portions connected with the periphery of the bottom surface of the mounting body22along the diametrical direction thereof and vertical portions suspended from outer ends of the respective horizontal portions. The supporting bodies12are vertically movably attached to the vertical portions of the fixed members14via the elevation guide mechanisms15.

The elevation guide mechanisms15have vertically extending linear guides15A fixed to the vertical portions of the fixed members14and engaging members15B to be engaged with the linear guides15A. The two wire materials11are moved vertically between the grooves13in which the two wire materials11are respectively received and above of the mounting surface of the mounting body22by moving the supporting bodies12vertically along the linear guide15A via the engaging member15B.

As shown inFIG. 1B, each of the supporting bodies12includes a cylindrical body12A, a cylindrical protrusion12B projecting upward from an upper end of the cylindrical body12A while being coaxial with the cylindrical body12A, and a spring member12C provided in the cylindrical body12A. Further, as illustrated inFIG. 1C, two adjacent supporting bodies12are connected with each other by a connecting member12D to maintain the distance therebetween. Moreover, the spring member12C in the cylindrical body12A has an upper end connected with an end portion of the corresponding wire material11and a lower end fixed to a bottom surface of the cylindrical body12A, and applies tensile force to the corresponding wire material11. That is, each pair of supporting bodies has therein respective spring member connected with opposite end of each of the wire materials11, and the spring members apply tensile force to the respective wire materials. Thus, due to the constant application of the tensile force by the spring member12C, the wire materials11do not lose their tension even if the wire materials11are extended or contracted by the temperature of the mounting body22, thereby reliably supporting the semiconductor wafer.

As depicted inFIG. 1D, the width and the depth of the grooves13formed on the mounting surface of the mounting body22are greater than the thickness of the wire materials11, and the wire materials11are brought into contact with the bottom surfaces of the grooves13when the supporting bodies12reach the lowermost end. In the present embodiment, the thickness of the wire materials11is, e.g., about 0.2 mm; the width of the grooves13is, e.g., about 0.6 mm, and the depth of the grooves13is, e.g., about 1.0 mm.

Further, a plurality of circular first adsorption grooves22A for vacuum-adsorbing the semiconductor wafer is formed in a concentric circular shape on the mounting surface of the mounting body22, and these first adsorption grooves22A communicate with each other by second adsorption grooves22B formed in a diametrical direction of the mounting body22. Openings are formed in desired portions of the first adsorption grooves22A to be connected with a gas exhaust line (not shown) formed inside the mounting body22. The first and the second adsorption grooves22A and22B intersect the grooves13, as can be seen fromFIG. 1C. At the intersection portions, the first and the second adsorption grooves22A and22B communicate with each other by a passageway22C formed below the grooves13, and the semiconductor wafer is adsorbed and held on the mounting surface through the first and the second absorption grooves22A and22B.

Further, as described inFIGS. 1A and 1C, two pairs of stopper plates16corresponding to the two pairs of supporting bodies12are fixed to side surfaces of the mounting body21. The stopper plates16horizontally extend from the side surfaces of the mounting table main body21to correspond to the supporting bodies12provided thereabove.

While the mounting body22is lowered by the elevation driving mechanism23of the mounting table20, the stopper plates16are brought into contact with the lower ends of the supporting bodies12. The supporting bodies12are relatively moved up by the stopper plates16with respect to the fixed members14until the mounting body22reaches the lowermost position, so that the two pairs of wire materials11are raised from the mounting surface of the mounting body22by a predetermined distance. The supporting bodies12are raised vertically by the elevation guide mechanisms15while being relatively moved up by the stopper plates16with respect to the fixed members14.

Hereinafter, an operation of the transfer mechanism10of the present embodiment will be described with reference toFIGS. 2A and 3C. The mounting table20moves toward the loader chamber via the XY table30under the control of the control unit to thereby wait for the semiconductor wafer, as shown inFIG. 2A. In order to transfer the semiconductor wafer from the wafer carrying mechanism40to the mounting table20(seeFIGS. 3A and 3B), the mounting body22is lowered by the elevation driving mechanism23, and the two pairs of supporting bodies12come into contact with the stopper plates16fixed to the mounting table main body21, as illustrated inFIG. 2B.

When the mounting body22is further lowered to be close to the mounting table main body21, the supporting bodies12are moved vertically upward by the stopper plates16relatively to the fixed members14. Thus, the two wire materials11are raised from the grooves13of the mounting body22by a predetermined distance to thereby receive the semiconductor wafer, as described inFIG. 2C.

When the mounting table20is being in ready for receiving the semiconductor wafer, the wafer carrying mechanism40moves from the loader chamber toward above of the mounting table20, and the semiconductor wafer W reaches directly above the mounting table20, as illustrated inFIG. 3A. Thereafter, while the wafer carrying mechanism40is lowered in a space between the two wire materials11and the mounting surface of the mounting body22, the semiconductor wafer W is delivered and mounted onto the two wire materials11, as shown inFIG. 3B. Next, the wafer carrying mechanism40retreats from above of the mounting table20to the loader chamber and, the mounting body22is raised by the elevation driving mechanism23. Further, the two wire materials11are received in the two grooves13of the mounting body22and, the semiconductor wafer W is mounted on the mounting surface of the mounting body22.

Moreover, when the mounting body22is raised by the elevation driving mechanism23, the two pairs of supporting bodies12are moved down relatively to the fixed members14through the elevation guide mechanism15while being supported by the stopper plates16, and when the mounting body22is further raised, the supporting bodies12rise from the stopper plates16, respectively, as shown inFIG. 4.

Next, while the mounting table20moves in X, Y, Z and θ directions, the alignment of the semiconductor wafer W and the probe card is carried out by the alignment mechanism. Thereafter, the mounting table20reaches a predetermined position below the probe card. In that position, the mounting body22is raised by the elevation driving mechanism23. Accordingly, the semiconductor wafer W is brought into electrical contact with the probes of the probe card, thereby inspecting electrical characteristics of the semiconductor wafer W by the probes.

In such a case unlike in the conventional case, the mounting body22is not provided with through holes, so that the highly reliable inspection can be carried out with high accuracy while preventing leakage of electromagnetic waves from the bottom surface of the mounting body22toward the mounting surface and generation of electrical noise. In addition, unlike in the conventional case, the mounting body22is not provided with elevating pins and through holes, and the semiconductor wafer W is transferred by the two insulating and heat-resistant wire materials11. Therefore, discharge does not occur in the mounting body22, and devices of the semiconductor wafer W or the probes are not damaged.

Further, even in the case of performing high-temperature inspection for a vehicle-loaded device, the absence of through holes in the mounting body22makes it possible to uniformly cool the entire surface of the semiconductor wafer W without generating heat spots. As a consequence, highly reliable inspection can be carried out with high accuracy.

As described above, in accordance with the present embodiment, the transfer mechanism10includes: the two insulating and heat-resistant wire materials11disposed spaced apart from each other by a distance so as to transverse the mounting table20(the mounting body22); the two pairs of supporting bodies12disposed at the outside of the mounting body22in the horizontal direction thereof, for stretching the wire materials11in parallel with the mounting surface of the mounting body22; the two grooves13formed on the mounting surface of the mounting body22to receive therein the respective wire materials11; and the elevation driving mechanism23for vertically moving the wire materials11between above of the mounting body22and the grooves13.

In this configuration, when the elevation driving mechanism23is driven under the control of the control unit, the two wire materials11are raised through the supporting bodies12and the elevation guide mechanism15, so that the semiconductor wafer W (seeFIGS. 3A and 3B) is transferred between the wafer carrying mechanism40(seeFIGS. 3A and 3B) and the mounting body22. Accordingly, the highly reliable inspection can be performed with high accuracy without generating electrical noise or heat spots.

Further, in accordance with the present embodiment, the mounting table20includes the mounting table main body21, the mounting body22movable vertically with respect to the mounting table main body21, and the elevation driving mechanism23for vertically moving the mounting body22with respect to the mounting table main body21. Moreover, the mounting table main body21has the stopper plates16to bring into contact with the lower ends of the two pairs of supporting bodies12, and the mounting body22has the elevation guide mechanisms15to guide vertical movement of the respective supporting bodies12. Accordingly, the semiconductor wafer W can be moved vertically with high accuracy by the elevation guide mechanisms15, and semiconductor wafers can be mounted at the same position on the mounting surface of the mounting body22.

Second Embodiment

A transfer mechanism10A in accordance with the second embodiment is basically the same as that of the first embodiment except that there is provided an elevation driving mechanism for vertically moving only the wire materials as shown inFIGS. 5A to 5C. Therefore, in the present embodiment, the present invention will be described by giving like reference numerals to like or corresponding parts of the first embodiment.

As shown in, e.g.,FIGS. 5A to 5C, in the transfer mechanism10A of the present embodiment, cylinder mechanisms17serving as a first elevation driving mechanism are provided at vertical portions of the fixed members14fixed on the bottom surface of the mounting body22to correspond to the two pairs of supporting bodies12. Upper ends of rods17A of the cylinder mechanisms17are connected with lower ends of the supporting bodies12.

The rods17A are extended and contracted by the cylinder mechanisms17under the control of the control unit to move the supporting bodies12vertically. The two pairs of supporting bodies12move vertically along the side surfaces of the mounting body22through the elevation guide mechanisms15attached to the side surfaces of the mounting body22in a vertical direction of the mounting body22and, further, the two wire materials11move vertically between the grooves13of the mounting body22and above of the mounting body22.

In the present embodiment, the cylinder mechanisms17serve as the first elevation driving mechanism for vertically moving only the wire materials11via the supporting bodies12, and the second elevation driving mechanism23serves as an elevation driving mechanism for vertically moving only the mounting body22.

Hereinafter, an operation of the transfer mechanism10A of the present embodiment will be described with reference toFIGS. 5A to 5C.FIGS. 5A to 5Cshow an operation of transferring an inspected semiconductor wafer W on the mounting table20to the wafer carrying mechanism40. When the inspection of the semiconductor wafer W is completed, the mounting table20moves toward the loader chamber and waits for the wafer carrying mechanism40.

That is, as illustrated inFIG. 5A, the mounting table20waits while mounting thereon the inspected semiconductor wafer W. In order to transfer the semiconductor wafer W from the mounting table20to the wafer carrying mechanism40, the rods17A of the cylinder mechanisms17are extended up under the control of the control unit, as shown inFIG. 5B. Accordingly, the two pairs of supporting bodies12are raised along the side surfaces of the mounting body22through the elevation guide mechanisms15. Along with the upward movement of the two pairs of supporting bodies12, the two wire materials11mount thereon the semiconductor wafer W and are raised from the grooves13of the mounting body22beyond the mounting surface by a predetermined distance, so that the semiconductor wafer is being ready to be transferred.

After the semiconductor wafer is being ready to be transferred, the wafer carrying mechanism40moves from the loader chamber toward a gap between the mounting surface of the mounting table20and the semiconductor wafer W, as illustrated inFIG. 5C. Next, the wafer carrying mechanism40moves up to receive the semiconductor wafer W on the two wire materials11and reaches a position slightly above the two wire materials11. Then, the wafer carrying mechanism40transfers the semiconductor wafer W from the mounting table20to a predetermined position in the loader chamber. Thereafter, a next semiconductor wafer W to be inspected is transferred by the wafer carrying mechanism40from the loader chamber to above the mounting table20, and then is mounted on the mounting table20through the processes shown inFIGS. 2A to 4. Next, the electrical characteristics of the semiconductor wafer W are inspected in the same manner described in the first embodiment.

As set forth above, in accordance with the second embodiment, the semiconductor wafer W can be transferred between the mounting body22and the wafer carrying mechanism40by vertically moving the two wire materials11, and the vertical movement of the two wire materials11is performed by extending/contracting the cylindrical mechanisms17corresponding to the two pairs of supporting bodies12without vertically moving the mounting body22. Accordingly, it is possible to obtain the operation effects same as those in the first embodiment.

Moreover, the present invention is not limited to the above-described embodiments, and the components thereof can be appropriately modified if necessary. For example, although two wire materials11are provided in the above-described embodiments, the number of wire materials may be three or more, and the number of supporting bodies may increase depending on the number of wire materials. In addition, the wire material is not particularly limited as long as it is an insulating material, and the first and the second elevation driving mechanism are not limited to those of the above-described embodiments.

The present invention can be preferably used as a transfer mechanism for a target object to be inspected which is used in a probe apparatus.