JP7544573B2 - Multi-probe - Google Patents

Description

The present invention relates to a prober that inspects the electrical characteristics of multiple chips formed on a semiconductor wafer, and is particularly suitable for a multi-prober that uses a single alignment device and multiple head stages to contact the probe needles with the wafer using vacuum suction force and aligns them during contact.

The semiconductor manufacturing process involves many steps, and various inspections are performed at each manufacturing step to ensure quality and improve yield. For example, when multiple semiconductor device chips are formed on a semiconductor wafer, the electrode pads of the semiconductor device of each chip are connected to a test head, and power and test signals are supplied from the test head. The signals output by the semiconductor device are then measured by the test head and electrically inspected to see if they are operating normally.

In order to improve throughput while suppressing increases in installation area and equipment costs, a prober having multiple measurement units is known, and is described in, for example, Patent Document 1. This prober has a stacked structure (multi-stage structure) in which multiple measurement units are stacked in multiple stages, and is a multi-prober that performs wafer-level inspection for each measurement unit.

A multi-prober uses one alignment device and multiple head stages to perform alignment when the probe needles come into contact with the wafer. Therefore, if the probe needles are brought into contact with the wafer using the lifting axis of the alignment device, the alignment device will be occupied by one head stage during testing. Therefore, multi-probers use contact by vacuum suction force, and during testing, the alignment device and the wafer chuck on which the wafer is placed are separated. In Patent Document 1, the internal space formed between the probe card and the wafer chuck is reduced in pressure, thereby drawing the wafer chuck toward the probe card.

JP 2019-149447 A

In the above conventional technology, the load of the wafer chuck's components may cause the wafer chuck to tilt or become misaligned. In this case, the parallelism between the probe card and the wafer deteriorates, and each probe needle of the probe card cannot be brought into uniform contact with the electrode pads of each chip on the wafer. This results in a decrease in the measurement accuracy of wafer-level inspection.

In probers that use vacuum suction to make contact between the probe needles and the wafer, if an unbalanced load is applied to the wafer chuck, the wafer chuck will tilt, causing an imbalance in the amount of overdrive required for proper contact. For this reason, it is necessary to balance the wafer chuck using a cancellation mechanism that has a counterweight attached to the opposite side to where the wiring is attached, to deal with unbalanced loads caused by the wiring and piping attached to the end of the wafer chuck. However, this cancellation mechanism cannot handle cases where the number of pipings increases and the weight of the piping changes due to the presence or absence of coolant or temperature changes.

The object of the present invention is to solve the problems of the conventional technology described above, and to always ensure proper contact in a prober that uses vacuum suction force to contact a probe needle with a wafer by eliminating uneven load on the wafer chuck caused by wiring and piping, and by suppressing tilt of the wafer chuck.

To achieve the above object, the present invention provides a multi-prober having multiple measurement units and performing alignment when a probe needle contacts a wafer in the multiple measurement units using a single alignment device, comprising a wafer chuck on which the wafer is placed and which is detachably supported and fixed to the alignment device, two rotating shafts provided 180 degrees opposite each other at a position passing through the center of gravity of the wafer chuck, a semicircular ring shaped and supported by the two rotating shafts on the outer circumferential side of the wafer chuck, and a cable guide device having one end connected to the semicircular ring via a moving end fitting and the other end fixed via a fixed end fitting.

Furthermore, in the above multi-probe, it is desirable that the semicircular ring be rotatable in the height direction of the wafer chuck around the two rotation axes.

Furthermore, in the above multi-prober, it is preferable that a cable rotation shaft is provided on the cable guide device side of the moving end fitting, and when the wafer chuck is lowered, the cable guide device rotates by the two rotation shafts and the cable rotation shaft.

Furthermore, in the above multi-probe, it is preferable to provide an alignment side ball caster and a stage side ball caster fixed to the moving end fitting of the cable guide device, the alignment side ball caster resting on the alignment side load receiver during the alignment, and the stage side ball caster resting on the stage side load receiver during contact.

Furthermore, in the above multi-probe, it is preferable that the alignment device detachably supports the wafer chuck by vacuum suction.

Furthermore, in the above multi-probe, it is desirable that the alignment device be configured to be movable between the multiple measurement units and shared between the multiple measurement units arranged on the same stage.

Furthermore, in the above multi-probe, it is desirable that a heating/cooling mechanism is provided inside the wafer chuck as a heating/cooling source.

Furthermore, it is preferable that the above multi-probe is provided with a cooling pipe that is housed and guided in the cable guide device.

According to the present invention, a semicircular ring shaped like a ring is supported by two rotating shafts arranged 180 degrees apart at a position passing through the center of gravity of the wafer chuck, and the cable guide device is connected to the semicircular ring, eliminating uneven loads caused by wiring and piping to the wafer chuck. This makes it possible to suppress tilting of the wafer chuck and ensure proper contact.

FIG. 1 is an external view showing the overall configuration of a prober according to an embodiment of the present invention; FIG. 2 is a plan view showing the prober shown in FIG. FIG. 2 is a front view of the measurement unit shown in FIG. 1 , illustrating the internal structure of the measurement unit; Schematic diagram showing the configuration of the measurement unit FIG. 1 is a side view showing a state in which the wafer chuck 50 is drawn toward the probe card 56 (a side view showing the measurement unit in a state in which inspection can be started). FIG. 1 is a perspective view of a conventional wafer chuck 50 viewed obliquely from below. FIG. 7 is a side view of the wafer chuck 50 in the conventional example of FIG. FIG. 7 is a side view showing a state in which the wafer chuck 50 in the conventional example of FIG. 6 is separated from the probe card 56. FIG. 1 is a perspective view of a wafer chuck 50 according to an embodiment of the present invention, viewed obliquely from below. FIG. 10 is a partially enlarged side view of FIG. A side view of a wafer chuck 50 in one embodiment. FIG. 1 is a side view showing a state in which the wafer chuck 50 is separated from the probe card 56 in one embodiment.

Figure 1 is an external view showing the overall configuration of a multi-probe 10 according to an embodiment of the present invention. Figure 2 is a plan view of the multi-probe 10 shown in Figure 1. Figure 3 is a diagram showing the internal structure of the measurement unit 12 in Figure 1, as seen from the front side (loader unit 14 side).

As shown in Figures 1 and 2, the multi-prober 10 includes a loader section 14 that supplies and collects the wafer W (see Figure 4) to be inspected, and a measurement unit 12 that is disposed adjacent to the loader section 14 and has multiple measurement sections 16. In the measurement unit 12, when the wafer W is supplied from the loader section 14 to each measurement section 16, each measurement section 16 inspects the electrical characteristics of each chip on the wafer W (wafer-level inspection).

The wafers W inspected by each measuring section 16 are then collected by the loader section 14. The loader section 14 and the measuring units 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 section.

The loader section 14 has a load port 18 on which the wafer cassette 20 is placed, and a transport unit 22 that transports wafers W between each measurement section 16 of the measurement unit 12 and the wafer cassette 20. The transport unit 22 has a transport unit drive mechanism (not shown) and is configured to be movable in the X direction and Z direction, and is also configured to be rotatable in the θ direction (around the Z direction). The transport unit 22 also has a transport arm 24, and the transport unit drive mechanism allows the transport arm 24 to be extended and retracted back and forth.

A suction pad (not shown) is provided on the upper surface of the transport arm 24, and the transport arm 24 holds the wafer W by vacuum-adhering the back surface of the wafer W with the suction pad. As a result, the wafer W in the wafer cassette 20 is taken out by the transport arm 24 of the transport unit 22 and transported to each measurement section 16 of the measurement unit 12 while being held on its upper surface. In addition, the inspected wafer W is returned from each measurement section 16 to the wafer cassette 20 via the reverse route.

As shown in FIG. 3, the measurement unit 12 has a stacked structure (multi-stage structure) in which multiple measurement parts 16 are stacked in multiple stages, and each measurement part 16 is arranged two-dimensionally along the X and Z directions. In FIG. 3, four measurement parts 16 are stacked in three stages in the Z direction in the X direction. Each measurement part 16 has the same configuration and is equipped with a wafer chuck 50, a probe card 56, etc. Here, in FIG. 3, an example is described in which the measurement unit 12 has a stacked structure (multi-stage structure) in which multiple measurement parts 16 are stacked in multiple stages, but a case in which there is only one stage rather than multiple stages is also included in the scope of the present invention.

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 constitutes 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.

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 configured on the wafer W for electrical testing, and detects output signals from each chip to measure whether it is operating normally.

The pogo frame 58 has a large number of pogo pins (not shown) that electrically connect the terminals formed on the lower surface (the surface facing the pogo frame 58) of the test head 54 to the terminals formed on the upper surface (the surface facing the pogo frame 58) of the probe card 56. In addition, the test head 54, the pogo frame 58, and the probe card 56 are integrated by a suction means or the like.

The probe card 56 is provided with a plurality of probe needles 66, each of which protrudes downward from the lower surface of the probe card 56 (the surface facing the wafer chuck 50). The probe needles 66 are electrically connected to the respective terminals of the test head 54 via the pogo frame 58.

The wafer W is placed on the wafer chuck 50 by vacuum suction or the like. The wafer chuck 50 is supported and fixed to the alignment device 70 so that it can be attached and detached freely. The alignment device 70 moves the wafer chuck 50 in the X, Y, Z, and θ directions to perform relative positioning, i.e. alignment, between the wafer W held on the wafer chuck 50 and the probe card 56.

Figure 5 is a side view of the measurement unit 16, showing the state in which the wafer chuck 50 is pulled toward the probe card 56 and the measurement unit 16 in a state in which testing can begin. The outer periphery 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.

The Z-axis moving/rotating unit 72 moves (raises) the wafer chuck 50 toward the probe card 56, and brings the chuck seal rubber 64 into contact with the underside of the head stage 52. Then, an internal space S is formed that is surrounded by the wafer chuck 50, the probe card 56 (head stage 52), and the chuck seal rubber 64.

Then, the internal space S is depressurized by a suction device (e.g., a vacuum pump) (not shown), and the wafer chuck 50 is drawn toward the probe card 56 (head stage 52). This causes each probe needle 66 of the probe card 56 to come into contact with the electrode pad of each chip on the wafer W, making it possible to start the inspection. The chuck seal rubber 64 is an example of an annular seal member.

The inside of the wafer chuck 50 is provided with a heating/cooling mechanism (not shown) as a heating/cooling source so that electrical characteristics testing can be performed on the chips at high temperatures (e.g., up to 150°C) or low temperatures (e.g., down to -40°C). Therefore, the wafer chuck 50 is a movable part, and is connected to a control part (not shown) and the like via a cable guide device 40 (see FIG. 6) that guides wiring and piping.

The cable guide device 40 is a component that houses and protects and guides wiring and piping connected to the moving part, and is made up of small parts connected together like a chain. In particular, when electrical characteristic testing is performed in low temperature conditions, i.e., in the case of low temperature specifications, the cooling piping through which the cooling liquid flows is housed and guided in the cable guide device 40.

The alignment device 70 detachably supports the wafer chuck 50 by vacuum suction or the like. The alignment device 70 also aligns the relative positions of the wafer W held on the wafer chuck 50 and the probe card 56. The alignment device 70 detachably supports and fixes the wafer chuck 50 and moves the wafer chuck 50 in the Z-axis direction. The alignment device 70 includes a Z-axis moving/rotating unit 72 that rotates in the θ direction around the Z-axis, an X-axis moving stage 74 that supports the Z-axis moving/rotating 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.

An alignment device 70 is provided for each stage (see FIG. 3), and is configured to be movable between the multiple measurement units 16 arranged on each stage by an alignment device drive mechanism (not shown). In other words, the alignment device 70 is shared between the multiple measurement units 16 arranged on the same stage, and moves between the multiple measurement units 16 arranged on the same stage.

Figure 6 is a perspective view of a conventional wafer chuck 50 viewed from diagonally below, showing its relationship with the cable guide device 40. One end of the cable guide device 40 is connected via a moving end fitting 41 at the end of the outer periphery of the wafer chuck 50, indicated by the arrow M. The other end of the cable guide device 40 is fixed via a fixed end fitting 42. The counterweight 100 is attached to the side opposite the position where the cable guide device 40 is attached. In this way, the counterweight 100 cancels the uneven load caused by the wiring and piping, and balances the wafer chuck 50.

Figure 7 is a side view of the wafer chuck 50 in the conventional example of Figure 6, showing the wafer chuck 50 being pulled toward the probe card 56. Figure 8 is a side view of the wafer chuck 50 in the conventional example of Figure 6, showing the wafer chuck 50 being pulled away from the probe card 56.

A cable rotation shaft 43 is provided on both ends of the cable guide device 40, that is, on the cable guide device 40 side of the moving end fitting 41, and a fixed side rotation shaft 44 is provided on the fixed end fitting 42. When the wafer chuck 50 is pulled away from the probe card 56 and lowered, the cable guide device 40 rotates in the direction of arrow K as shown in FIG. 8 by the cable rotation shaft 43 and the fixed side rotation shaft 44.

In the conventional example shown in Figures 7 and 8, when the number of pipes increases and the weight of the pipes changes depending on the presence or absence of cooling liquid or temperature changes, the counterweight 100 cannot always maintain balance. In addition, because the cable guide device 40 has a cable rotation shaft 43 and a fixed side rotation shaft 44 at both ends, the cable guide device 40 tilts as the wafer chuck 50 rises and falls. This results in poor space efficiency, and when the number of pipes for cooling, etc. increases, it is not possible to accommodate this in terms of space.

Figure 9 is a perspective view of a wafer chuck 50 according to an embodiment, seen from diagonally below. The wafer chuck 50 has a semicircular ring 91 made of a semicircular ring-shaped plate attached to the outer peripheral side and supported by two rotating shafts 92 and 93. The two rotating shafts 92 and 93 are provided 180 degrees opposite each other at positions passing through the center C of the wafer chuck 50, i.e., the center of gravity.

Therefore, the semicircular ring 91 can rotate around the rotation axes 92, 93 in the Z direction (see FIG. 4), which is actually the height direction of the wafer chuck 50, as indicated by the arrow H. One end of the cable guide device 40 is connected to the semicircular ring 91 at the point indicated by the arrow M via a moving end fitting 41. The other end of the cable guide device 40 is fixed via a fixed end fitting 42. The wiring or piping from the wafer chuck 50 to the control unit is protected and guided by the cable guide device 40 before being connected.

The load from the wiring or piping is applied to the wafer chuck 50 via the semicircular ring 91 and the rotating shafts 92 and 93. However, since the rotating shafts 92 and 93 are located at the center C of the wafer chuck 50, i.e., at the center of gravity, the force point of the load from the wiring or piping is the rotating shafts 92 and 93, which is the center of gravity of the wafer chuck 50. Therefore, the wafer chuck 50 does not receive a moment due to the force from the cable guide device 40, and therefore balance is maintained. Therefore, the wafer chuck 50 is not affected by the unbalanced load from the wiring or piping even without the provision of a counterweight 100.

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

The alignment side ball caster 45 rests on the alignment side load receiver 47 when aligning the wafer chuck 50. The stage side ball caster 46 rests on the stage side load receiver 48 when contact is made, that is, when the wafer chuck 50 is pulled toward the probe card 56 and the alignment device 70 moves to another measurement unit 16.

As a result, the load of the wiring and piping is received by the alignment device 70 or the head stage 52 during both alignment and contact. Therefore, even during alignment or contact, no load is applied to the wafer chuck 50, regardless of the presence or absence of piping carrying a cooling liquid or temperature changes, so tilting of the wafer chuck 50 is suppressed.

Figure 11 is a side view of the wafer chuck 50 in the embodiment of Figure 9, showing the wafer chuck 50 being pulled towards the probe card 56. Figure 12 is a side view showing the wafer chuck 50 in the embodiment being pulled away from the probe card 56. A cable rotation shaft 49 is provided on the cable guide device 40 side of the moving end fitting 41.

When the wafer chuck 50 is pulled away from the probe card 56 and lowered, the semicircular ring 91 rotates around the rotation shafts 92, 93 in the Z direction (see FIG. 4). Similarly, the cable guide device 40 rotates by the rotation shafts 93, 92 and the cable rotation shaft 49 to the state shown in FIG. 12. The cable guide device 40 is kept horizontal without tilting as the wafer chuck 50 is raised and lowered. This allows the space of the cable guide device 40 to be used efficiently, making it possible to add cooling piping, etc.

As described above, according to this embodiment, it is possible to prevent the wafer chuck 50 from tilting or shifting due to the influence of the load of the components of the wafer chuck 50. This ensures the parallelism of the probe card 56 and the wafer W, and allows each probe needle 66 of the probe card 56 to uniformly contact the electrode pads of each chip on the wafer W. This improves the measurement accuracy of the wafer-level inspection.

In addition, this embodiment eliminates the need for a counterweight 100 to balance the wafer chuck 50, improving space efficiency and making it possible to accommodate an increase in the number of pipes, weight, etc.

10... multi-prober 12... measuring unit 14... loader section 16... measuring section 18... load port 20... wafer cassette 21... operation panel 22... transport unit 24... transport arm 30... housing 34... frame member 40... cable guide device 41... moving end fitting 42... fixed end fitting 43, 49... cable rotation shaft 44... fixed side rotation 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 portion 56...probe card 58...pogo frame 64...chuck seal rubber 66...probe needle 70...alignment device 72...Z-axis moving/rotating portion 74...X-axis moving stage 76...Y-axis moving stage 80...test head holding portion 87...spring receiving portion 88...spring member 91...semicircular rings 92, 93...rotating shaft 100...counterweight C...center H, K, M...arrow S...internal space W...wafer

Claims (8)

A multi-prober having a plurality of measurement units, in which alignment and contact between a probe needle and a wafer are performed in the plurality of measurement units by a single alignment device,
a wafer chuck on which the wafer is placed and which is detachably supported and fixed to the alignment device;
Two rotation shafts are provided at 180 degrees opposite sides of a position passing through the center of gravity of the wafer chuck;
a semicircular ring having a semicircular ring shape and attached to an outer peripheral side surface of the wafer chuck by being supported by the two rotating shafts;
a cable guide device having one end connected to the semicircular ring via a moving end fitting and the other end fixed via a fixed end fitting;
A multi-probe comprising: The multi-probe according to claim 1, characterized in that the semicircular ring is rotatable in the height direction of the wafer chuck around the two rotation axes. The multi-probe according to claim 1 or 2, characterized in that it has a cable rotation shaft provided on the cable guide device side of the moving end fitting, and when the wafer chuck descends, the cable guide device rotates by the two rotation shafts and the cable rotation shaft. The multi-probe according to any one of claims 1 to 3, characterized in that it comprises an alignment side ball caster and a stage side ball caster fixed to the moving end fitting of the cable guide device, the alignment side ball caster resting on the alignment side load receiver during the alignment, and the stage side ball caster resting on the stage side load receiver during contact. The multi-probe according to any one of claims 1 to 4, characterized in that the alignment device detachably supports the wafer chuck by vacuum suction. The multi-probe according to any one of claims 1 to 5, characterized in that the alignment device is configured to be movable between the multiple measurement units and is shared between the multiple measurement units arranged on the same stage. The multi-probe according to any one of claims 1 to 6, characterized in that a heating/cooling mechanism is provided inside the wafer chuck as a heating/cooling source. 8. The multi-prober according to claim 1, further comprising a cooling pipe that is accommodated and guided by the cable guide device.