Multi-prover

Abstract

To eliminate an unbalanced load on a wafer chuck caused by wiring or piping in a multi-prober so as to suppress tilting of the wafer chuck, thereby ensuring appropriate contact.SOLUTION: A multi-prober uses one alignment device 70 to align, in each of a plurality of measurement parts 16, a probe needle 66 with a wafer W when they come into contact with each other. The multi-prober comprises: a wafer chuck 50 which is supported by and fixed to the alignment device 70 in an attachable / detachable manner; two rotation shafts 92, 93 which are provided 180 degrees opposite to each other at positions passing through the center of gravity of the wafer chuck 50; a semicircular ring 91, shaped into a semicircular ring, which is pivoted by and fitted to a lateral face on the outer peripheral side of the wafer chuck 50 by the two rotation shafts 92, 93; and a cable guide device 40 which has one end connected to the semicircular ring 91 via a movable-end metal fitting 41 and has the other end fixed via a fixed-end metal fitting 42.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a prober for inspecting the electrical characteristics of a plurality of chips formed on a semiconductor wafer. In particular, in a multi-head stage with a single alignment device, it is suitable for a multi-prober that makes contact between a probe needle and a wafer by means of a vacuum adsorption force and performs alignment during contact.

Background Art

[0002] The semiconductor manufacturing process has a large number of steps, and various inspections are performed in various manufacturing steps to ensure quality and improve yield. For example, at the stage where a plurality of chips of semiconductor devices are formed on a semiconductor wafer, the electrode pads of the semiconductor devices of each chip are connected to a test head, and a power supply and test signals are supplied from the test head. Then, the signals output by the semiconductor device are measured by the test head, and it is electrically inspected whether it operates normally.

[0003] In addition, in order to improve throughput while suppressing an increase in installation area and device cost, a prober having a plurality of measurement units is known, for example, as described in Patent Document 1. This prober has a stacked structure (multi-stage structure) in which a plurality of measurement units are stacked in multiple stages, and is a multi-prober that performs wafer-level inspection for each measurement unit.

[0004] The multi-prober performs alignment during contact between the probe needle and the wafer in a plurality of head stages with a single alignment device. Therefore, when the contact between the probe needle and the wafer is made by the lifting axis of the alignment device, the alignment device will be occupied by one head stage during the test. Therefore, the multi-prober adopts contact by means of a vacuum adsorption force, and during the test, the alignment device and the wafer chuck on which the wafer is placed are disconnected. Patent Document 1 has a configuration in which the internal space formed between the probe card and the wafer chuck is depressurized, and the wafer chuck is attracted toward the probe card.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the above prior art, the wafer chuck may be tilted or displaced due to the influence of the load or the like caused by the components of the wafer chuck. In this case, the parallelism between the probe card and the wafer deteriorates, and each probe needle of the probe card cannot be uniformly brought into contact with the electrode pads of each chip of the wafer. As a result, the measurement accuracy of the wafer-level inspection decreases.

[0007] In a prober that makes contact between the probe needle and the wafer by means of a vacuum adsorption force, when an uneven load is applied to the wafer chuck, the wafer chuck tilts, and the over-drive amount required for proper contact becomes uneven. Therefore, it is necessary to balance the wafer chuck with a canceling mechanism in which a counterweight is attached on the side opposite to the position where the wiring is attached for the uneven load caused by the wiring and piping attached to the end of the wafer chuck. However, this canceling mechanism cannot cope with cases where the number of pipes increases and the weight of the pipes changes due to the presence or absence of a coolant or a temperature change.

[0008] An object of the present invention is to solve the problems of the above prior art, and in a prober that makes contact between the probe needle and the wafer by means of a vacuum adsorption force, to eliminate the uneven load on the wafer chuck caused by wiring and piping, and to suppress the tilt of the wafer chuck to always ensure proper contact.

Means for Solving the Problems

[0009] To achieve the above object, the present invention is a multi-prober having a plurality of measurement units, and performing alignment at the time of contact between a probe needle and a wafer in the plurality of measurement units with one alignment device, including: a wafer chuck on which the wafer is placed and which is detachably supported and fixed to the alignment device; two rotation shafts provided on the 180-degree opposite side at a position passing through the center of gravity of the wafer chuck; a semi-circular ring which is in a semi-circular ring shape and is pivotally supported and attached to the outer peripheral side surface of the wafer chuck by the two rotation shafts; and a cable guiding device having one end connected to the semi-circular ring via a moving terminal fitting and the other end fixed via a fixed terminal fitting.

[0010] Also, in the above multi-prober, it is desirable that the semi-circular ring is rotatable in the height direction of the wafer chuck around the two rotation shafts.

[0011] Furthermore, in the above multi-prober, it is desirable to include a cable rotation shaft provided on the cable guiding device side of the moving terminal fitting, and when the wafer chuck descends, the cable guiding device rotates by the two rotation shafts and the cable rotation shaft.

[0012] Furthermore, in the above multi-prober, it is desirable to include an alignment side ball caster and a stage side ball caster fixed to the moving terminal fitting of the cable guiding device, where the alignment side ball caster rides on an alignment side load receiver during alignment, and the stage side ball caster is placed on a stage side load receiver during contact.

[0013] Furthermore, in the above multi-prober, it is desirable that the alignment device detachably supports the wafer chuck by vacuum adsorption.

[0014] Furthermore, in the above-described multi-prober, it is desirable that the alignment device be configured to be movable relative to the plurality of measurement units and shared among the plurality of measurement units arranged in the same stage.

[0015] Furthermore, in the above-described multi-prober, it is desirable that a heating / cooling mechanism as a heating / cooling source be provided inside the wafer chuck.

[0016] Furthermore, in the above-described multi-prober, it is desirable that a cooling pipe housed and guided by the cable guiding device be provided.

Advantages of the Invention

[0017] According to the present invention, a semi-circular ring having a semi-circular ring shape is pivotally supported by two rotating shafts provided on the 180-degree opposite side at a position passing through the center of gravity of the wafer chuck, and the cable guiding device is connected to the semi-circular ring. Therefore, it is possible to eliminate the uneven load caused by wiring and piping to the wafer chuck. Accordingly, it is possible to suppress the inclination of the wafer chuck and ensure appropriate contact.

Brief Description of the Drawings

[0018]

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Mode for Carrying Out the Invention

[0019] FIG. 1 is an external view showing the overall configuration of the multi-prober 10 according to an embodiment of the present invention. FIG. 2 is a plan view of the multi-prober 10 shown in FIG. 1. FIG. 3 is a view showing the internal structure of the measurement unit 12 of FIG. 1, and is a view of the measurement unit 12 as viewed from the front side (loader unit 14 side).

[0020] As shown in FIGS. 1 and 2, the multi-prober 10 includes a loader unit 14 that supplies and recovers a wafer W (see FIG. 4) to be inspected, and a measurement unit 12 that is arranged adjacent to the loader unit 14 and has a plurality of measurement units 16. In the measurement unit 12, when the wafer W is supplied from the loader unit 14 to each measurement unit 16, each measurement unit 16 inspects the electrical characteristics of each chip of the wafer W (wafer-level inspection).

[0021] Then, the wafer W inspected by each measurement unit 16 is recovered by the loader unit 14. The loader unit 14 and the measurement unit 12 are housed in a housing 30 (see FIG. 3). The multi-prober 10 also includes an operation panel 21 and a control device (not shown) that controls each part.

[0022] The loader unit 14 includes a load port 18 on which the wafer cassette 20 is placed, and a transfer unit 22 that transfers the wafer W between each measurement unit 16 of the measurement unit 12 and the wafer cassette 20. The transfer unit 22 is provided with a transfer unit drive mechanism (not shown), and is configured to be movable in the X direction and the Z direction, and is also configured to be rotatable in the θ direction (around the Z direction). Further, the transfer unit 22 includes a transfer arm 24, and the transfer arm 24 can be extended and retracted back and forth by the transfer unit drive mechanism.

[0023] An adsorption pad (not shown) is provided on the upper surface portion of the transfer arm 24, and the transfer arm 24 holds the wafer W by vacuum-adsorbing the back surface of the wafer W with the adsorption pad. Thereby, the wafer W in the wafer cassette 20 is taken out by the transfer arm 24 of the transfer unit 22 and is transferred to each measurement unit 16 of the measurement unit 12 while being held on its upper surface. Also, the inspected wafer W after the inspection is returned from each measurement unit 16 to the wafer cassette 20 along the reverse path.

[0024] As shown in FIG. 3, the measurement unit 12 has a stacked structure (multi-stage structure) in which a plurality of measurement units 16 are stacked in multiple stages, and each measurement unit 16 is two-dimensionally arranged along the X direction and the Z direction. In FIG. 3, four measurement units 16 are stacked in three stages in the Z direction in the X direction. Note that each measurement unit 16 has the same configuration and is configured to include a wafer chuck 50, a probe card 56, and the like. Here, in FIG. 3, an example in which the measurement unit 12 has a stacked structure (multi-stage structure) stacked in multiple stages by a plurality of measurement units 16 has been described, but the case of only one stage instead of multiple stages is also included in the scope of the present invention.

[0025] Next, the configuration of the measurement unit 16 will be described. FIG. 4 is a side view showing the configuration of the measurement unit 16. The measurement unit 16 includes a wafer chuck 50, a head stage 52, a test head 54, a probe card 56, and a pogo frame 58. The head stage 52 is supported by a frame member 34 that forms a part of the housing 30. The receiving portion 54a of the test head 54 is supported above the head stage 52 by a test head holding portion 80.

[0026] A spring member 88 is interposed between the receiving portion 54a of the test head 54 and a spring receiving portion 87 fixed to the frame member 34. The test head 54 is electrically connected to the probe needles 66 of the probe card 56, and supplies power and test signals to each chip formed on the wafer W for electrical inspection, and detects output signals from each chip to measure whether it operates normally.

[0027] The pogo frame 58 includes a number of pogo pins (not shown) that electrically connect the terminals formed on the lower surface of the test head 54 (the surface facing the pogo frame 58) and the terminals formed on the upper surface of the probe card 56 (the surface facing the pogo frame 58). Also, the test head 54, the pogo frame 58, and the probe card 56 are integrated by suction means or the like.

[0028] The probe card 56 is provided with a plurality of probe needles 66, and each probe needle 66 is formed to protrude downward from the lower surface of the probe card 56 (the surface facing the wafer chuck 50). Also, the probe needles 66 are electrically connected to the respective terminals of the test head 54 via the pogo frame 58.

[0029] The wafer chuck 50 adsorbs and places the wafer W by vacuum adsorption or the like. The wafer chuck 50 is detachably supported and fixed to the alignment device 70. The alignment device 70 performs alignment, that is, relative positioning between the wafer W held by the wafer chuck 50 and the probe card 56, by moving the wafer chuck 50 in the X, Y, Z, and θ directions.

[0030] FIG. 5 is a side view showing the measurement unit 16 in a state where the wafer chuck 50 is drawn toward the probe card 56, indicating the measurement unit 16 in a state where inspection can be started. An outer peripheral portion of the upper surface (wafer placement surface) of the wafer chuck 50 is provided with a chuck seal rubber 64 as an elastic ring-shaped seal member.

[0031] The Z-axis movement / rotation unit 72 moves (raises) the wafer chuck 50 toward the probe card 56, and brings the chuck seal rubber 64 into contact with the lower surface of the head stage 52. Then, an internal space S surrounded by the wafer chuck 50, the probe card 56 (head stage 52), and the chuck seal rubber 64 is formed.

[0032] Then, by reducing the pressure in the internal space S by a suction device (for example, a vacuum pump) (not shown), the wafer chuck 50 is drawn toward the probe card 56 (head stage 52). As a result, each probe needle 66 of the probe card 56 comes into contact with the electrode pads of each chip of the wafer W, and the inspection can be started. Note that the chuck seal rubber 64 is an example of an annular seal member.

[0033] Inside the wafer chuck 50, a heating / cooling mechanism (not shown) as a heating / cooling source is provided so that electrical characteristics inspection can be performed on the chips in a high-temperature state (for example, up to 150° C.) or a low-temperature state (for example, as low as -40° C.). Therefore, the wafer chuck 50 serves as a movable part and is connected via a cable guide device 40 (see FIG. 6) through which wiring and piping are guided to a control unit (not shown) or the like.

[0034] The cable guide device 40 is a component that houses and protects and guides wiring, piping, etc. connected to the movable part, and small components are connected like a chain. In particular, when performing electrical characteristics inspection in a low-temperature state, that is, in a low-temperature specification, a cooling pipe through which a coolant flows is housed and guided by the cable guide device 40.

[0035] The alignment device 70 detachably supports the wafer chuck 50 by means of vacuum adsorption or the like. Further, the alignment device 70 performs relative alignment between the wafer W held by the wafer chuck 50 and the probe card 56. Then, the alignment device 70 detachably supports and fixes the wafer chuck 50 and moves the wafer chuck 50 in the Z-axis direction. And the alignment device 70 includes a Z-axis movement / rotation unit 72 that rotates in the θ direction with the Z-axis as the rotation center, an X-axis moving stage 74 that supports the Z-axis movement / rotation unit 72 and moves in the X-axis direction, and a Y-axis moving stage 76 that supports the X-axis moving stage 74 and moves in the Y-axis direction.

[0036] The alignment devices 70 are provided for each stage (see FIG. 3), and are configured to be mutually movable among a plurality of measurement units 16 arranged in each stage by an alignment device drive mechanism (not shown). That is, the alignment devices 70 are shared among the plurality of measurement units 16 arranged in the same stage, and move mutually among the plurality of measurement units 16 arranged in the same stage.

[0037] FIG. 6 is a perspective view of the conventional wafer chuck 50 as viewed obliquely from below, showing the relationship with the cable guiding device 40. One end of the cable guiding device 40 is connected via a moving end fitting 41 at a point M indicated by an arrow, which is the end on the outer peripheral side of the wafer chuck 50. The other end of the cable guiding device 40 is fixed via a fixed end fitting 42. The counterweight 100 is attached on the side opposite to the position where the cable guiding device 40 is attached. Thereby, the counterweight 100 cancels the eccentric load caused by wiring and piping, and balances the wafer chuck 50.

[0038] FIG. 7 is a side view of the wafer chuck 50 portion in the conventional example of FIG. 6, showing a state where the wafer chuck 50 is attracted toward the probe card 56. FIG. 8 is a side view showing a state where the wafer chuck 50 in the conventional example of FIG. 6 is separated from the probe card 56.

[0039] At both ends of the cable guiding device 40, that is, on the cable guiding device 40 side of the moving terminal fitting 41, a cable rotating shaft 43 is provided, and a fixed side rotating shaft 44 is provided on the fixed terminal fitting 42. When the wafer chuck 50 is separated from the probe card 56 and descends, the cable guiding device 40 rotates as indicated by the arrow K in FIG. 8 around the cable rotating shaft 43 and the fixed side rotating shaft 44.

[0040] In the conventional examples shown in FIGS. 7 and 8, when the number of pipes increases and the weight of the pipes changes due to the presence or absence of the coolant or temperature changes, etc., the counterweight 100 could not always maintain balance. Also, since the cable rotating shaft 43 and the fixed side rotating shaft 44 are provided at both ends of the cable guiding device 40, the cable guiding device 40 tilts as the wafer chuck 50 moves up and down. Therefore, the space efficiency is poor, and when the number of pipes for cooling etc. increases, it was impossible to cope with it in terms of space.

[0041] FIG. 9 is a perspective view of the wafer chuck 50 according to the embodiment as seen from obliquely below. The wafer chuck 50 is attached with two semi-circular rings 91 formed of semi-circular ring-shaped plates on the outer peripheral side surfaces being pivotally supported by two rotating shafts 92 and 93. The two rotating shafts 92 and 93 are provided on opposite sides by 180 degrees at a position passing through the center C of the wafer chuck 50, that is, the center of gravity position.

[0042] Therefore, the semi-circular ring 91 is rotatable around the rotating shafts 92 and 93 in the direction of the arrow H, actually the Z direction (see FIG. 4) which is the height direction of the wafer chuck 50. One end of the cable guiding device 40 is connected to the semi-circular ring 91 at the arrow M point via the moving terminal fitting 41. The other end of the cable guiding device 40 is fixed via the fixed terminal fitting 42. The wiring or piping from the wafer chuck 50 to the control unit is protected and guided by the cable guiding device 40 and connected.

[0043] The load caused by wiring or piping is applied to the wafer chuck 50 via the semi-circular ring 91 and the rotating shafts 92 and 93. However, since the rotating shafts 92 and 93 are provided at the center C of the wafer chuck 50, that is, at the center of gravity position, the points of force of the load caused by wiring or piping become the rotating shafts 92 and 93 and the center of gravity position of the wafer chuck 50. Therefore, the wafer chuck 50 does not receive a moment due to the force from the cable guiding device 40, so the balance is maintained. Therefore, the wafer chuck 50 is not affected by the uneven load caused by wiring or piping even without providing the counterweight 100.

[0044] Also, the alignment side ball caster 45 and the stage side ball caster 46 are fixed to the cable guiding device 40 (the moving end fitting 41). FIG. 10 is a partially enlarged side view of FIG. 9, showing the relationship between the alignment side ball caster 45 and the stage side ball caster 46, and the alignment device 70 and the head stage 52.

[0045] The alignment side ball caster 45 rides on the alignment side load receiver 47 during the alignment of the wafer chuck 50. The stage side ball caster 46 is placed on the stage side load receiver 48 during contact, that is, when the wafer chuck 50 is pulled toward the probe card 56 and the alignment device 70 moves to the other measurement unit 16.

[0046] As a result, the load of the wiring and piping is received on the alignment device 70 or the head stage 52 side in both cases during alignment and during contact. Therefore, even during alignment or contact, regardless of the presence or absence of the pipe through which the cooling liquid passes and the temperature change, no load is applied to the wafer chuck 50, so the inclination of the wafer chuck 50 is suppressed.

[0047] FIG. 11 is a side view of the wafer chuck 50 in the embodiment of FIG. 9, showing a state where the wafer chuck 50 is attracted toward the probe card 56. FIG. 12 is a side view showing a state where the wafer chuck 50 in the embodiment is separated from the probe card 56. On the side of the cable guiding device 40 of the moving terminal fitting 41, a cable rotating shaft 49 is provided.

[0048] When the wafer chuck 50 is separated from the probe card 56 and descends, the semi-circular ring 91 rotates about the rotation shafts 92 and 93 in the Z direction (see FIG. 4). Similarly, the cable guiding device 40 rotates about the rotation shafts 93, 92 and the cable rotating shaft 49 to reach the state shown in FIG. 12. Then, the cable guiding device 40 is kept horizontal without tilting as the wafer chuck 50 moves up and down. As a result, the space of the cable guiding device 40 can be effectively utilized, making it possible to add cooling pipes or the like.

[0049] As described above, according to this embodiment, it is possible to suppress the occurrence of tilting and displacement of the wafer chuck 50 due to the influence of loads and the like caused by the components of the wafer chuck 50. Thereby, the parallelism between the probe card 56 and the wafer W can be ensured, and each probe needle 66 of the probe card 56 can be uniformly brought into contact with the electrode pads of each chip of the wafer W. And the measurement accuracy of the wafer level inspection can be improved.

[0050] Also, according to this embodiment, a counterweight 100 for balancing the wafer chuck 50 is not required, improving space efficiency, and making it possible to cope with an increase in the number and weight of pipes.

Description of Reference Numerals

[0051] 10... Multi-prober 12... Measurement unit 14... Loader unit 16... Measurement section 18... Load port 20... Wafer cassette 21... Operation panel 22…Conveyor unit 24…Conveyor arm 30…Housing 34…Frame member 40…Cable guiding device 41…Moving terminal fitting 42…Fixed terminal fitting 43, 49…Cable rotating shaft 44…Fixed side rotating shaft 45…Alignment side ball caster 46…Stage side ball caster 47…Alignment side load receiver 48…Stage side load receiver 50…Wafer chuck 52…Head stage 54…Test head 54a…Receiving part 56…Probe card 58…Pogo frame 64…Chuck seal rubber 66…Probe needle 70…Alignment device 72…Z-axis movement and rotation part 74…X-axis moving table 76…Y-axis moving table 80…Test head holding part 87…Spring receiving part 88…Spring member 91…Semicircular ring 92, 93…Rotating shaft 100…Counterweight C…Center H, K, M…Arrow S…Internal space W…Wafer

Claims

1. A multi-prober having a plurality of measurement units, in which a single alignment device performs contact and alignment between a probe needle and a wafer in the plurality of measurement units, a wafer chuck on which the wafer is placed and which is detachably supported and fixed to the alignment device; a cable guide device for guiding wiring connected to the wafer chuck; An alignment side ball caster fixed to a moving end of the cable guide device; and a stage side ball caster; The alignment side ball caster rides on an alignment side load receiver during the alignment, and the stage side ball caster is placed on the stage side load receiver during contact.

2. 2. The multi-prober according to claim 1, wherein said alignment device detachably supports said wafer chuck by vacuum suction.

3. 2. The multi-probe according to claim 1, wherein the alignment device is configured to be movable between the plurality of measurement units and is shared among the plurality of measurement units arranged on the same stage.

4. 2. The multi-prober according to claim 1, wherein a heating / cooling mechanism serving as a heating / cooling source is provided inside said wafer chuck.

5. 2. The multi-probe according to claim 1, further comprising a cooling pipe that is accommodated and guided in the cable guide device.

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