Prober and probe inspection method

Abstract

To provide a prober and a probe inspection method that can stably release a wafer chuck without damaging a wafer or a probe.SOLUTION: A prober includes a probe card having a plurality of probes on a surface facing a wafer chuck, a sealing member forming an internal space between the wafer chuck and the probe card, a communication path that communicates between the internal space and the external space, and has an effective cross-sectional area that can secure the air flow rate necessary to release the wafer chuck suctioned and held on the probe card side at the target release speed due to the air flowing into the internal space from the external space when the internal space is switched to a non-sealed state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a prober and a probe inspection method for inspecting electrical characteristics of a plurality of semiconductor devices (chips) formed on a semiconductor wafer, and more particularly to a multi-stage prober and a probe inspection method having a plurality of measuring units. [Background technology]

[0002] The semiconductor manufacturing process has many steps, and various inspections are performed in each manufacturing process to ensure quality and improve yield. For example, at the stage where multiple semiconductor device chips are formed on a semiconductor wafer, a wafer-level inspection is performed in which the electrode pads of the semiconductor device of each chip are connected to a test head, power and test signals are supplied from the test head, and the signals output by the semiconductor device are measured by the test head to electrically inspect whether the semiconductor device operates normally.

[0003] After the wafer-level inspection, the wafer is attached to a frame and cut into individual chips using a dicer. Only chips that are confirmed to work properly are packaged in the next assembly process, while chips that do not work are removed from the assembly process. The packaged final products are then inspected for delivery.

[0004] Wafer-level testing is performed using a prober that brings probes into contact with the electrode pads of each chip on the wafer. The probes are electrically connected to terminals of a test head, and power and test signals are supplied from the test head to each chip via the probes, while the output signals from each chip are detected by the test head to measure whether they are operating normally.

[0005] In the semiconductor manufacturing process, wafers are becoming larger and further miniaturized (integrated) in order to reduce manufacturing costs, and the number of chips formed on one wafer is becoming very large. Accordingly, the time required to inspect one wafer using a prober is also increasing, and there is a demand for improving throughput. In order to improve throughput, multi-probing is being used, which allows multiple chips to be inspected simultaneously by providing multiple probes. In recent years, the number of chips to be inspected simultaneously is increasing, and there are also attempts to inspect all chips on a wafer simultaneously. For this reason, the allowable error in aligning the electrode pads and the probes to contact each other is decreasing, and there is a demand for improving the positional accuracy of the movement of the prober.

[0006] On the other hand, the easiest way to increase throughput is to increase the number of probers, but increasing the number of probers causes a problem that the installation area of ​​the probers in the manufacturing line also increases. Furthermore, increasing the number of probers increases the equipment cost accordingly. Therefore, there is a demand for increasing throughput while suppressing the increase in installation area and equipment cost.

[0007] In light of this background, for example, Patent Document 1 proposes a test device equipped with multiple measurement units (multi-stage prober). In this test device, an alignment device that performs relative alignment between the wafer and the probe card is configured to be able to move between the measurement units.

[0008] However, although the test device described in Patent Document 1 can save space and reduce costs by sharing an alignment device among the measurement sections, it has the following problems.

[0009] That is, when the moving distance of the alignment device becomes long, the moving mechanism for moving the alignment device to each measurement unit and the support member (frame) to which the moving mechanism is attached are easily distorted due to the weight of the alignment device and the effects of thermal expansion or contraction, which causes a decrease in the positional accuracy of the alignment device that has moved to each measurement unit. For this reason, it takes time to detect the positions of the electrode pads and probes on the wafer using the imaging means, resulting in a problem that the alignment operation takes time and the throughput is slow.

[0010] In response to this, the applicant of the present application has proposed a multi-stage prober equipped with multiple measurement units that solves the above problems (see Patent Document 2). In this prober, the alignment device that has been moved to each measurement unit is positioned and fixed by a positioning and fixing device, so that it is possible to improve throughput while maintaining the accuracy of the moving position of the alignment device and suppressing increases in installation area and equipment costs. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] JP 2010-186998 A [Patent Document 2] JP 2014-192218 A Summary of the Invention [Problem to be solved by the invention]

[0012] Incidentally, in the conventional probers described in Patent Documents 1 and 2, after the wafer and the probe card are aligned relative to each other with the wafer chuck detachably supported by the alignment device, the wafer chuck is transferred from the alignment device to the probe card. That is, after the wafer chuck is raised toward the probe card by the lifting mechanism (Z-axis moving / rotating unit) of the alignment device, the internal space formed between the probe card and the wafer chuck is depressurized to attract the wafer chuck to the probe card, and each probe of the probe card comes into contact with the electrode pad of each chip on the wafer at a predetermined pressure.

[0013] However, in conventional probers, after the wafer-level inspection is completed, in order to transfer the wafer chuck from the probe card side to the alignment device, an operation (release operation) is performed to release (separate) the wafer chuck from the probe card side by breaking the vacuum in the internal space. In this case, since it takes a long time to break the vacuum in the internal space, an unstable state in which some of the probes are in contact with the wafer is likely to occur due to the inclination of the wafer chuck and the variation in the length (needle length) of the probes. In such an unstable state, the binding force is small and the positional relationship between the probe and the wafer is easily shifted, and there is a risk of damaging the wafer or the probe at that point.

[0014] The present invention has been made in consideration of the above circumstances, and has an object to provide a prober and a probe inspection method that can stably release a wafer chuck without damaging the wafer or the probe. [Means for solving the problem]

[0015] In order to solve the above problems, a prober according to a first aspect of the present invention comprises a wafer chuck for holding a wafer, a probe card having a plurality of probes on a surface facing the wafer chuck, an annular sealing member for forming an internal space between the wafer chuck and the probe card, a mechanical lifting means having a wafer chuck fixing part for removably fixing the wafer chuck and for raising and lowering the wafer chuck fixed to the wafer chuck fixing part, a negative pressure applying means for adsorbing and holding the wafer chuck on the probe card side by applying negative pressure to the internal space, a communicating passage connecting the internal space and an external space, the communicating passage having an effective cross-sectional area capable of ensuring a flow rate of air required to release the wafer chuck from the probe card side at a target release speed when the internal space is switched to an unsealed state, and a shutter means attached to the communicating passage and capable of selectively switching the internal space between an unsealed state and a sealed state.

[0016] A prober according to a second aspect of the present invention is the prober of the first aspect, further comprising a shutter control means for controlling the shutter means to switch the internal space from a non-sealed state to a sealed state when the wafer chuck is released from the probe card side.

[0017] A probe inspection method according to a third aspect of the present invention is a probe inspection method in which a wafer chuck is adsorbed and held on the probe card by applying negative pressure to an internal space formed between a wafer chuck and a probe card, and a wafer held on the wafer chuck is inspected.The method includes a step of opening a communication passage connecting the internal space and the external space by a shutter means when releasing the wafer chuck from the probe card side, thereby making the internal space non-sealed, and the communication passage has an effective cross-sectional area capable of ensuring the flow rate of air required to release the wafer chuck from the probe card side at a target release speed when the internal space is switched to an non-sealed state. Effect of the Invention

[0018] According to the present invention, the wafer chuck can be stably released without damaging the wafer and the probe. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is an external view showing an overall configuration of a prober according to a first embodiment; [Diagram 2] FIG. 1 is a plan view showing an overall configuration of a prober according to a first embodiment; [Diagram 3] FIG. 1 is a schematic diagram showing a configuration of a measurement unit in a prober according to a first embodiment; [Figure 4] FIG. 4 is a schematic diagram showing the configuration of a measurement section in the measurement unit shown in FIG. [Diagram 5] Diagram showing the relationship between positioning pins and V-blocks [Figure 6] A plan view showing a wafer chuck. [Figure 7] FIG. 2 is an enlarged plan view of the shutter means; [Figure 8] FIG. 1 is a functional block diagram showing a configuration of a control device of a prober according to a first embodiment; [Figure 9] 1 is a flowchart showing a contact operation in a prober according to a first embodiment; [Figure 10] FIG. 1 is a diagram for explaining a contact operation in a prober according to a first embodiment; [Figure 11] FIG. 1 is a timing chart of a contact operation in the prober according to the first embodiment; [Figure 12] 1 is a flowchart showing a release operation in a prober according to a first embodiment; [Figure 13] FIG. 1 is a diagram for explaining a release operation in the prober according to the first embodiment; [Figure 14] FIG. 1 is a timing chart showing a release operation in the prober according to the first embodiment; [Figure 15] A graph showing the relationship between the chuck release speed and the effective cross-sectional area of ​​the communication passage [Figure 16] FIG. 13 is a schematic diagram showing the configuration of a prober according to a second embodiment; [Figure 17]FIG. 13 is a diagram for explaining a contact operation in a prober according to a second embodiment; [Figure 18] FIG. 11 is a diagram for explaining a release operation in a prober according to a second embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a prober and a probe inspection method according to the present invention will be described with reference to the accompanying drawings.

[0021] (First embodiment) 1 and 2 are an external view and a plan view showing the overall configuration of a prober 10 according to a first embodiment.

[0022] 1 and 2, the prober 10 of this embodiment includes a loader section 14 that supplies and collects a wafer W (see FIG. 4) to be inspected, and a measurement unit 12 disposed adjacent to the loader section 14. The measurement unit 12 has a plurality of measurement sections 16, and when a 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 wafer W inspected by each measurement section 16 is then collected by the loader section 14. The prober 10 also includes an operation panel 22, a control device (see FIG. 8) to be described later, and the like.

[0023] The loader section 14 has a load port 18 on which a wafer cassette is placed, and a transport unit 24 that transports the wafer W between each measurement section 16 of the measurement unit 12 and the wafer cassette.

[0024] The loader unit 14 has a card stocker 20 on which a card (probe card 32) is placed. In the example shown in Fig. 1, the measurement units 16 and the card stockers 20 are arranged in the X direction in equal numbers and at equal pitches (same intervals).

[0025] The transport unit 24 includes a transport unit drive mechanism (not shown), and is configured to be movable in the X and Z directions, and is also configured to be rotatable in the θ direction (around the Z direction).

[0026] The transfer unit 24 also includes a transfer arm 26 that is configured to be freely extended and retracted back and forth by the transfer unit drive mechanism. The transfer arm 26 has suction holes (not shown) on its upper surface, and the transfer arm 26 holds the wafer W by vacuum suctioning the back surface of the wafer W through the suction holes. As a result, the wafer W in the wafer cassette is taken out by the transfer arm 26 of the transfer unit 24 and transferred to each measurement section 16 of the measurement unit 12 while being held on its upper surface. After inspection, the inspected wafer W is returned to the wafer cassette from each measurement section 16 via the reverse route.

[0027] Fig. 3 is a schematic diagram showing the configuration of a measurement unit in a prober according to an embodiment of the present invention, Fig. 4 is a schematic diagram showing the configuration of a measurement section in the measurement unit shown in Fig. 3.

[0028] 3, the measurement unit 12 has a stacked structure (multi-stage structure) in which a plurality of measurement parts 16 are stacked in multiple stages, and each measurement part 16 is two-dimensionally arranged along the X direction and the Z direction. In this embodiment, as an example, four measurement parts 16 are stacked in three stages in the Z direction in the X direction.

[0029] The measurement unit 12 includes a housing (not shown) having a lattice shape in which a plurality of frames are combined in a lattice shape. This housing is formed by combining a plurality of frames extending in the X direction, Y direction, and Z direction in a lattice shape, and components of the measurement section 16 are disposed in each space formed by these frames.

[0030] Each measurement unit 16 has the same configuration, and includes a head stage 30, a probe card 32, and a wafer chuck 34, as shown in Fig. 4. Each measurement unit 16 is provided with a test head (not shown). The test head is supported above the head stage 30 by a test head holding unit (not shown).

[0031] The head stage 30 is supported by a frame member (not shown) that constitutes a part of the housing, and a probe card 32 is detachably attached and fixed to the head stage 30. The probe card 32 attached and fixed to the head stage 30 is provided so as to face a wafer holding surface 34a of a wafer chuck 34. The probe card 32 is replaced depending on the wafer W (device) to be inspected.

[0032] The probe card 32 is provided with a plurality of probes 36, such as cantilevers or spring pins, arranged corresponding to the positions of the electrode pads of each chip on the wafer W to be inspected. Each probe 36 is electrically connected to a terminal of a test head (not shown), and power and test signals are supplied from the test head to each chip via each probe 36, and output signals from each chip are detected by the test head to measure whether the chip operates normally. A detailed description of the connection between the probe card 32 and the test head will be omitted.

[0033] The probe 36 has spring characteristics, and contacts the electrode pad with a predetermined contact pressure by raising the contact point from the tip position of the probe 36. When the probe 36 contacts the electrode pad in an overdrive state during electrical testing, the tip of the probe 36 sinks into the surface of the electrode pad and forms a needle mark on the surface of the electrode pad. Note that the overdrive state refers to a state in which the electrode pad, i.e., the surface of the wafer W, is raised by a distance α to a position higher than the tip position of the probe 36 so that the electrode pad and the probe 36 are surely in contact with each other, taking into consideration the inclination of the wafer W and the arrangement surface of the tips of the probes 36 and the variation in the tip positions of the probes 36. Note that the amount of movement by which the surface of the wafer W is further raised from the tip position (contact position) of the probe 36, i.e., the above distance α, is referred to as the overdrive amount.

[0034] The wafer chuck 34 fixes the wafer W by vacuum suction. The wafer chuck 34 has a wafer holding surface 34a on which the wafer W to be inspected is placed, and a plurality of suction ports 40 are provided on the wafer holding surface 34a (only one is shown in FIG. 4). The suction port 40 is connected to a suction device (vacuum source) 44 such as a vacuum pump via a suction path 42 formed inside the wafer chuck 34. A wafer suction solenoid valve 46 is provided on the suction path connecting the suction device 44 and the suction path 42. The wafer suction solenoid valve 46 is controlled by a wafer suction solenoid valve control unit 110 (see FIG. 8).

[0035] An elastic ring-shaped seal member (chuck seal rubber) 48 is provided outside the wafer holding surface 34a of the wafer chuck 34 so as to surround the wafer W held on the wafer holding surface 34a. When the wafer chuck 34 is moved (raised) toward the probe card 32 by the Z-axis moving / rotating unit 72 described below, the ring-shaped seal member 48 comes into contact with the lower surface of the head stage 30, thereby forming an internal space R (see FIG. 10) surrounded by the wafer chuck 34, the probe card 32, and the ring-shaped seal member 48. The ring-shaped seal member 48 is an example of an annular seal member of the present invention.

[0036] The head stage 30 is provided with a pressure supply port 50 for applying a negative pressure to the internal space R formed between the probe card 32 and the wafer chuck 34. The pressure supply port 50 is provided on the lower surface of the head stage 30 and opens into the internal space R. The pressure supply port 50 is also formed at one end (the lower end in FIG. 4) of a supply path 52 formed inside the head stage 30, and the other end (the upper end in FIG. 4) of the supply path 52 is connected to one end of a pipe 60. That is, the pipe 60 communicates with the internal space R via the supply path 52 and the pressure supply port 50. The other end of the pipe 60 is connected to the suction device 44 (vacuum pump) via a pressure reducing regulator (vacuum electropneumatic regulator) 54.

[0037] The suction device 44 can reduce the pressure in the internal space R to a negative pressure that is lower than atmospheric pressure by discharging air from the internal space R through the piping 60. The pressure reduction regulator 54 can be set to any pressure (negative pressure) from atmospheric pressure to, for example, -100 kPa (gauge pressure), and when the pressure reduction regulator 54 is used to reduce the degree of vacuum (reduce the negative pressure), air flows into the internal space R from the air intake port 54a until a predetermined pressure is reached. The suction device 44 and the pressure reduction regulator 54 are an example of the negative pressure applying means of the present invention.

[0038] The wafer chuck 34 is provided with a communication passage 56 that communicates between the internal space R and the external space. One end of the communication passage 56 opens to an area of ​​the wafer holding surface 34a of the wafer chuck 34 near the outer periphery where the wafer W is not placed, and the other end of the communication passage 56 opens to a side surface of the wafer chuck 34.

[0039] Furthermore, the head stage 30 is provided with a shutter means 58 that can selectively switch between a connected state (non-sealed state) in which the internal space R is connected to the external space and a non-connected state (sealed state) in which the internal space R is not connected to the external space.

[0040] The shutter means 58 is composed of an air cylinder mechanism 300 and an on-off valve 302, and opens and closes the communication passage 56 by moving the on-off valve 302 back and forth between a closed position where the communication passage 56 is closed and an open position where the communication passage 56 is opened by the air cylinder mechanism 300. In other words, as the shutter means 58 is moved back and forth by the air cylinder mechanism 300, the internal space R is selectively switched between a non-communicating state and a communicating state.

[0041] The air cylinder mechanism 300 moves the on-off valve 302 back and forth in the horizontal direction, and is configured to include a cylinder 304, a piston 306 housed inside the cylinder 304, and a piston rod 308 fixed to the piston 306. The cylinder 304 is connected to an air cylinder drive device 310 via a gas supply path, and the piston 306 and the piston rod 308 move back and forth by the gas supplied from the air cylinder drive device 310. The on-off valve 302 is attached to the tip of the piston rod 308, and is configured to be able to move back and forth between an open position that opens the communication passage 56 and a cut-off position that cuts off the communication passage 56 in response to the forward and backward movements of the piston 306 and the piston rod 308. When the on-off valve 302 moves to the open position, the communication passage 56 is opened, and the internal space R is in a communicated state in which it is communicated with the external space via the communication passage 56. On the other hand, when the on-off valve 302 is moved to the blocking position, the communication passage 56 is blocked, and the internal space R is not in communication with the external space. The shutter means 58 (air cylinder mechanism 300) is controlled by the shutter control unit 116 (see FIG. 7), which will be described later.

[0042] As described above, according to this embodiment, since the shutter means 58 is provided on the head stage 30, the components of the shutter means 58 that act as heat dissipation elements are not provided on the wafer chuck 34, and the influence on the temperature distribution of the wafer chuck 34 can be eliminated. Furthermore, the elimination of the influence on the temperature distribution of the wafer chuck 34 improves the flatness of the wafer holding surface 34a of the wafer chuck 34. This allows the parallelism between the wafer W and the probe card 32 to be improved, and wafer level inspection can be performed with high accuracy. Furthermore, since the number of components mounted on the wafer chuck 34 can be reduced, it becomes easier to balance the weight of the wafer chuck 34. As a result, the contact operation and release operation by the vacuum suction method can be stably performed without destroying the weight balance of the wafer chuck 34. The shutter means 58 can also be provided on the wafer chuck 34 side.

[0043] In the present embodiment, as an example, the communication path 56 and the shutter means 58 provided in the wafer chuck 34 are selectively switched between a communication state (non-sealed state) in which the internal space R is communicated with the external space and a non-communication state (sealed state). Instead of the configuration of the present embodiment, for example, a communication path and a shutter means may be provided in the head stage 30 or the probe card 32. According to this configuration, the wafer chuck 34 is not provided with a communication path and a shutter means that serve as heat dissipation elements, so that the influence on the temperature distribution of the wafer chuck 34 can be reduced. Furthermore, the flatness of the wafer holding surface 34a of the wafer chuck 34 is improved by reducing the influence on the temperature distribution of the wafer chuck 34. This allows the parallelism between the wafer W and the probe card 32 to be increased, and wafer-level inspection can be performed with high accuracy. Furthermore, the number of parts mounted on the wafer chuck 34 can be reduced compared to the configuration of the present embodiment, so that the weight balance of the wafer chuck 34 can be easily achieved. As a result, during the contact operation and release operation of the wafer chuck 34, the weight balance of the wafer chuck 34 is not disturbed and the wafer chuck 34 can be transferred in a stable state.

[0044] Inside the wafer chuck 34, a heating / cooling mechanism (not shown) is provided as a heating / cooling source so that the electrical characteristics of the wafer W to be inspected can be inspected at a high temperature (for example, up to 150° C.) or at a low temperature (for example, down to −40° C.). As the heating / cooling mechanism, any suitable known heater / cooler can be used, and various types are conceivable, such as a double-layer structure with a heating layer of a surface heater and a cooling layer with a passage for a cooling fluid, or a single-layer heating / cooling device with a cooling pipe wrapped around a heater embedded in a thermal conductor. Also, instead of electrical heating, a device that circulates a thermal fluid or a Peltier element may be used.

[0045] The wafer chuck 34 is detachably supported and fixed to an alignment device 70, which will be described later. The alignment device 70 moves the wafer chuck 34 in the X, Y, Z, and θ directions to perform relative alignment between the wafer W held by the wafer chuck 34 and the probe card 32.

[0046] The alignment device 70 includes a Z-axis moving / rotating unit 72 that detachably supports and fixes the wafer chuck 34 and moves the wafer chuck 34 in the Z-axis direction while rotating it in the θ direction about the Z axis, an X-axis moving stage 74 that supports the Z-axis moving / rotating unit 72 and moves it in the X-axis direction, and a Y-axis moving stage 76 that supports the X-axis moving stage 74 and moves it in the Y-axis direction.

[0047] The Z-axis moving / rotating unit 72, the X-axis moving stage 74, and the Y-axis moving stage 76 are each configured to move or rotate the wafer chuck 34 in a predetermined direction by a mechanical driving mechanism including at least a motor. The mechanical driving mechanism may be, for example, a ball screw driving mechanism that combines a servo motor and a ball screw. The mechanical driving mechanism is not limited to the ball screw driving mechanism, and may be a linear motor driving mechanism or a belt driving mechanism. The Z-axis moving / rotating unit 72, the X-axis moving stage 74, and the Y-axis moving stage 76 are configured to change the moving distance, moving direction, moving speed, and acceleration of the wafer chuck 34 by each control unit described later. In this embodiment, specifically, the following configuration is provided.

[0048] The Z-axis moving / rotating unit 72 is an example of the mechanical lifting means of the present invention, and includes a Z-axis drive motor 122 (e.g., a stepping motor, a servo motor, a linear motor, etc.) (see FIG. 8) for moving the wafer chuck 34 in the Z-axis direction, and a Z-axis encoder (e.g., a rotary encoder or a linear scale, etc.) (not shown) for detecting the movement distance of the wafer chuck 34 in the Z-axis direction. The Z-axis drive motor 122 is controlled based on a motor control signal from a Z-axis movement control unit 106 (see FIG. 7), which will be described later, and drives the wafer chuck 34 to move to a target position at a desired movement speed or acceleration. In addition, the Z-axis encoder outputs an encoder signal in accordance with the movement of the wafer chuck 34.

[0049] Furthermore, the Z-axis moving / rotating unit 72 includes a rotary drive motor 124 (e.g., a stepping motor, a servo motor, a linear motor, etc.) (see FIG. 8) for rotating the wafer chuck 34 in the θ direction, and a rotary encoder (e.g., a rotary encoder, etc.) (not shown) for detecting the rotation angle of the wafer chuck 34 in the θ direction. The rotary drive motor 124 is controlled based on a motor control signal from a θ rotation control unit 108 (see FIG. 8) described later, and drives the wafer chuck 34 to move to a target position at a desired rotation speed or acceleration. Furthermore, the rotary encoder outputs an encoder signal in accordance with the rotation of the wafer chuck 34.

[0050] The X-axis moving stage 74 is equipped with an X-axis drive motor 118 (e.g., a stepping motor, a servo motor, a linear motor, etc.) (see FIG. 8) for moving the wafer chuck 34 in the X-axis direction, and an X-axis encoder (e.g., a rotary encoder, a linear scale, etc.) (not shown) for detecting the movement distance of the wafer chuck 34 in the X-axis direction. The X-axis drive motor 118 is controlled based on a motor control signal from an X-axis movement control unit 102 (see FIG. 8) described later, and drives the wafer chuck 34 to move to a target position at a desired movement speed or acceleration. In addition, the X-axis encoder outputs an encoder signal in accordance with the movement of the wafer chuck 34.

[0051] The Y-axis moving stage 76 is equipped with a Y-axis drive motor 120 (e.g., a stepping motor, a servo motor, a linear motor, etc.) (see FIG. 8) for moving the wafer chuck 34 in the Y-axis direction, and a Y-axis encoder (e.g., a rotary encoder or a linear scale, etc.) (not shown) for detecting the movement distance of the wafer chuck 34 in the Y-axis direction. The Y-axis drive motor 120 is controlled based on a motor control signal from a Y-axis movement control unit 104 (see FIG. 8), which will be described later, and drives the wafer chuck 34 to move to a target position at a desired movement speed or acceleration. In addition, the Y-axis encoder outputs an encoder signal in accordance with the movement of the wafer chuck 34.

[0052] The 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). That is, the alignment device 70 is shared between the multiple measurement units 16 (four in this example) arranged on the same stage, and moves between the multiple measurement units 16 arranged on the same stage. The alignment device 70 that has moved to each measurement unit 16 is fixed in a predetermined position by a positioning and fixing device (not shown), and the wafer chuck 34 is moved in the X, Y, Z, and θ directions to perform relative alignment between the wafer W held on the wafer chuck 34 and the probe card 32. Although not shown, the alignment device 70 includes a needle position detection camera and a wafer alignment camera in order to detect the relative positional relationship between the electrode pads of each chip of the wafer W held on the wafer chuck 34 and the probes 36. The alignment device drive mechanism is configured by a mechanical drive mechanism such as a ball screw drive mechanism, a linear motor drive mechanism, or a belt drive mechanism.

[0053] A ring-shaped seal member (Z-axis seal rubber) 78 having elasticity and formed in an annular shape along the outer periphery is provided on the wafer chuck support surface 72a of the Z-axis moving / rotating part 72 constituting the upper surface of the alignment device 70. A suction port 80 is provided on the inner side of the ring-shaped seal member 78 of the wafer chuck support surface 72a. The suction port 80 is connected to the suction device 44 via a suction path 82 formed inside the wafer chuck 34. A chuck fixing solenoid valve 84 and a throttle valve 86 are provided in this order from the suction device 44 side on the suction path connecting the suction device 44 and the suction path 82. The chuck fixing solenoid valve 84 is controlled by a chuck fixing solenoid valve control unit 112 (see FIG. 8 ) described later. The wafer chuck support surface 72a of the Z-axis moving / rotating part 72 is an example of a wafer chuck fixing part of the present invention. The suction port 80 provided on the wafer chuck support surface 72a is an example of a component of the wafer chuck fixing part.

[0054] Positioning pins 88 are provided on the outer side of the ring-shaped seal member 78 on the wafer chuck support surface 72a of the Z-axis moving / rotating section 72 so that the relative positional relationship of the wafer chuck 34 with respect to the alignment device 70 is always constant. As shown in FIG. 5, the positioning pins 88 are provided at three positions at equal intervals along the circumferential direction centered on the central axis of the wafer chuck 34 (only two are shown in FIG. 4). V-blocks 90, which are positioning members, are provided on the lower surface of the wafer chuck 34 at positions corresponding to the positioning pins 88. When the wafer chuck 34 is attracted and fixed by vacuum suction, the corresponding positioning pins 88 are engaged in the V-grooves of the V-blocks 90 to restrict the movement of the wafer chuck 34 in the horizontal direction (X direction and Y direction), thereby positioning the alignment device 70 and the wafer chuck 34 relative to each other. FIG. 5 is a diagram showing the corresponding relationship between the positioning pins 88 and the V-blocks 90. In FIG. 5, in order to simplify the drawing, configurations other than the positioning pin 88 and the V-block 90 are omitted.

[0055] In this embodiment, the alignment device 70 fixes the wafer chuck 34 by vacuum adsorption, but any fixing means other than vacuum adsorption may be used as long as it is capable of fixing the wafer chuck 34, and for example, the wafer chuck 34 may be fixed by mechanical means, etc.

[0056] FIG. 6 is a plan view showing the wafer chuck, and FIG. 7 is an enlarged plan view showing the shutter means.

[0057] 6, four shutter means 58 are attached to the wafer chuck 34. The shutter means 58 are provided corresponding to the communication passages 56 that communicate between the internal space R surrounded by the wafer chuck 34, the probe card 32, and the ring-shaped seal member 48 and the external space. The communication passages 56 are used for exhausting gas when cleaning the probe card 32 of the prober 10, etc.

[0058] As shown in Fig. 7, the shutter means 58 includes a driving unit 300. The driving unit 300 includes, for example, an air cylinder, and moves a piston 306 and a piston rod 308 in the length direction. As the driving unit 300, for example, one including a motor or a linear motor can also be used. Note that in Fig. 4 and the like, the shutter means 58 is shown in a simplified form.

[0059] The reference symbol 56A in the drawing denotes a sealing part (for example, a rubber packing, etc.). The sealing part 56A is attached to the tip of the on-off valve 302 (see FIG. 4), and when the on-off valve 302 is moved to close the communication passage 56, the sealing part 56A abuts against the opening of the communication passage 56 to ensure airtightness.

[0060] When the sealing part 56A comes into contact with the opening of the communication passage 56, the communication passage 56 is closed by the sealing part 56A, and the internal space R is isolated from the external space. On the other hand, when the sealing part 56A moves away from the opening of the communication passage 56, the communication passage 56 is opened, and the internal space R is connected to the external space. This allows the internal space R to be switched between being opened and being blocked.

[0061] In addition, reference numeral 50A in FIG. 7 denotes a connection portion that connects the supply path 52 and the pipe 60.

[0062] FIG. 8 is a functional block diagram showing the configuration of a control device of a prober according to an embodiment of the present invention.

[0063] As shown in FIG. 8, the control device of the prober 10 of this embodiment includes an overall control unit 100, an X-axis movement control unit 102, a Y-axis movement control unit 104, a Z-axis movement control unit 106, a θ rotation control unit 108, a wafer suction solenoid valve control unit 110, a chuck fixing solenoid valve control unit 112, a pressure control unit 115, a shutter control unit 116, etc.

[0064] The overall control unit 100 performs overall control of each unit constituting the prober 10. Specifically, the overall control unit 100 controls a contact operation for adsorbing and holding the wafer chuck 34 on the probe card 32 side, and a release operation for releasing (separating) the wafer chuck 34 from the probe card 32 side. In addition to these operations, the overall control unit 100 also performs movement control for moving the alignment device 70 between the measurement units 16, and controls the operation of wafer-level inspection by the test head. Note that controls other than the contact operation and release operation are not characteristic of the present invention, and therefore detailed explanations will be omitted.

[0065] The X-axis movement control unit 102 controls the drive of the X-axis drive motor 118 provided in the X-axis moving stage 74 to move the X-axis moving stage 74 in the X-axis direction, thereby moving the wafer chuck 34 in the X-axis direction. The Y-axis movement control unit 104 controls the drive of the Y-axis drive motor 120 provided in the Y-axis moving stage 76 to move the Y-axis moving stage 76 in the Y-axis direction, thereby moving the wafer chuck 34 in the Y-axis direction. The Z-axis movement control unit 106 controls the drive of the Z-axis drive motor 122 provided in the Z-axis moving / rotating unit 72 to raise and lower the Z-axis moving / rotating unit 72, thereby moving the wafer chuck 34 in the Z-axis direction. The θ rotation control unit 108 controls the drive of the rotation drive motor 124 provided in the Z-axis moving / rotating unit 72 to rotate the Z-axis moving / rotating unit 72 in the θ direction, thereby rotating the wafer chuck 34 in the θ direction.

[0066] The wafer suction solenoid valve control unit 110 controls the ON / OFF (open / close) of the wafer suction solenoid valve 46 to adjust the suction pressure by the suction port 40 and selectively switch between fixed and unfixed states of the wafer W to the wafer chuck 34.

[0067] The chuck fixing solenoid valve control unit 112 controls the ON / OFF (open / close) of the chuck fixing solenoid valve 84 to adjust the suction pressure by the suction port 80, and selectively switches between fixed and unfixed states of the wafer chuck 34 relative to the Z-axis moving / rotating unit 72.

[0068] The pressure control unit 115 controls the operation of the pressure reducing regulator 54 to set the internal pressure of the internal space R to a negative pressure lower than the atmospheric pressure.

[0069] The shutter control unit 116 selectively switches between opening and closing of the communication passage 56 that communicates between the internal space R and the external space by controlling the opening and closing of the shutter means 58. Here, the shutter control unit 116 functions as a shutter control unit.

[0070] Next, a contact operation (one example of a probe inspection method) in the prober 10 according to the first embodiment will be described with reference to Figures 9 to 11. This operation is performed under the control of the overall control unit 100.

[0071] FIG. 9 is a flow chart showing the contact operation in the prober according to the first embodiment. FIG. 10 is a diagram for explaining the contact operation in the prober according to the first embodiment. FIG. 11 is a timing chart showing the contact operation in the prober according to the first embodiment. Note that the time width of the timing chart shown in FIG. 11 is expressed to simplify the drawing and differs from the actual time. Also, the "Z-axis height" in FIG. 11 indicates the position (height position) in the Z-axis direction of the wafer chuck support surface 72a of the Z-axis moving / rotating part 72. Also, the "chuck height" in FIG. 11 indicates the height position of the wafer chuck 34 (specifically, the position in the Z-axis direction of the wafer holding surface 34a) when the tip position (contact position) of the probe 36 is set as the reference position (0 point position).

[0072] (Pre-action) The preliminary operation of the contact operation will be described.

[0073] First, as a preliminary operation for the contact operation, the alignment device 70 is moved to the measurement section 16 where the inspection will be performed, and then the wafer chuck 34 is transferred to the alignment device 70 while being positioned and fixed by a positioning and fixing device (not shown). Note that the transfer operation of the wafer chuck 34 before the start of the contact operation is not an essential part of the present invention, so a detailed description thereof will be omitted.

[0074] (Step S10: Wafer chuck fixing process) After the wafer chuck 34 is delivered to the alignment device 70, as shown in Fig. 10(A), the chuck fixing solenoid valve control unit 112 turns on (open) the chuck fixing solenoid valve 84 to attract and fix the wafer chuck 34 to the wafer chuck support surface 72a (see Fig. 4) of the Z-axis moving / rotating unit 72 (time T1 in Fig. 11). At this time, the positioning pin 88 of the Z-axis moving / rotating unit 72 is engaged with the V-groove of the V-block 90 of the wafer chuck 34, thereby performing relative positioning between the alignment device 70 and the wafer chuck 34.

[0075] Thereafter, when the wafer W is supplied (loaded) onto the wafer chuck 34 supported and fixed by the alignment device 70, the wafer adsorption solenoid valve control unit 110 turns the wafer adsorption solenoid valve 46 ON (open state) and adsorbs and fixes the wafer W onto the wafer holding surface 34a (see FIG. 4) (time T2 in FIG. 11).

[0076] (Step S12: Alignment process) Next, under the control of the overall control unit 100, the X-axis movement control unit 102, the Y-axis movement control unit 104, and the θ rotation control unit 108 control the X-axis drive motor 118, the Y-axis drive motor 120, and the rotation drive motor 124 based on the results of imaging by the needle position detection camera and the wafer alignment camera, to perform relative alignment between the wafer W held by the wafer chuck 34 and the probe card 32.

[0077] (Step S14: Shutter opening process) Next, as shown in FIG. 10(A), the shutter control section 116 opens the shutter means 58 to open the communication passage 56 (time T3 in FIG. 11).

[0078] The shutter-opening process only needs to be performed at least before the ring-shaped seal member 48 comes into contact with the head stage 30 (see FIG. 10(B)) in the Z-axis raising process described below. For example, the shutter-opening process may be performed between the wafer chuck fixing process and the alignment process, or may be performed prior to the wafer chuck fixing process. Furthermore, the shutter-opening process may be performed simultaneously with the wafer chuck fixing process or the alignment process.

[0079] (Step S16: Z-axis rising process) 10B and 10C, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to raise the Z-axis moving / rotating unit 72, thereby moving the wafer chuck 34 toward the probe card 32 (times T4 to T5 in FIG. 11). Specifically, the wafer chuck 34 is raised so that the wafer chuck 34 moves from a predetermined height position (standby position) to a height position where the ring-shaped seal member 48 contacts the head stage 30 (see FIG. 10B), and further, the wafer chuck 34 is raised to a position at least higher than the tip position (contact position) of the probe 36 (see FIG. 10C). As a result, each probe 36 of the probe card 32 contacts the electrode pad of each chip of the wafer W in an overdrive state.

[0080] In the Z-axis lifting step, the height to which the wafer chuck 34 is lifted by the Z-axis moving / rotating unit 72 is a height position that is 30 to 70% of the appropriate overdrive amount (appropriate OD position) of the probe card 32 from the tip position (contact position) of the probe 36. Alternatively, the height to which the wafer chuck 34 is lifted is a height position that is 0 to 70% of the appropriate overdrive amount. The Z-axis lifting step is an example of a wafer chuck moving step of the present invention.

[0081] (Step S18: Shutter Closing Process) 10(D), the shutter control unit 116 closes the shutter means 58 to block the communication path 56 (time T6 in FIG. 11). As a result, the internal space R formed between the wafer chuck 34 and the probe card 32 by the ring-shaped seal member 48 becomes in a non-communicating state (sealed state) that does not communicate with the external space.

[0082] (Step S20: Decompression process) Next, as shown in FIG. 10(D), the pressure control unit 115 controls the operation of the pressure reducing regulator 54 to start depressurizing the internal space R (time T7 in FIG. 11). At this time, the pressure control unit 115 sets a target pressure such that the wafer chuck 34 rises to the appropriate overdrive amount (appropriate OD position) of the probe card 32 when the fixation of the wafer chuck 34 by the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72 is released, and adjusts the internal pressure of the internal space R to the target pressure. The target pressure of the internal space R may be obtained empirically or experimentally, or may be obtained from a design value. For example, the target pressure can be determined from the reaction force (the reaction force when the probe 36 is crushed) received from the probe 36 when the wafer chuck 34 rises to the appropriate overdrive amount of the probe card 32, and the total number of the probes 36 provided on the probe card 32. If the total needle pressure of the probe card 32 (the sum of pressures received from the probes 36) is known, the required negative pressure can be obtained as the target pressure of the internal space R by dividing it by the area of ​​the surface (adsorption surface) surrounded by the ring-shaped seal member 48. However, it is necessary to set the target pressure of the internal space R taking into account the weight of the wafer chuck 34 and the reaction force caused by crushing the ring-shaped seal member 48. The depressurization process is an example of the negative pressure application process of the present invention.

[0083] In step S20, the target pressure is set, but the present invention is not limited to this. For example, a sensor that detects the relative height between the wafer chuck 34 and the head stage 30 may be used to measure the overdrive amount and perform feedback control to an appropriate overdrive amount.

[0084] (Step S22: Judgment step) Next, the pressure control unit 115 judges whether the internal pressure of the internal space R (pressure value P1) has reached the set pressure (pressure value P2) set by the pressure reducing regulator 54. This judgment is repeated until the internal pressure (pressure value P1) reaches the set pressure (pressure value P2), and when the set pressure (pressure value P2) has been reached, the process proceeds to the next step S24. As a result, when the internal pressure of the internal space R is stabilized at the set pressure, a wafer chuck fixation release step (step S24) described later is performed. The internal pressure of the internal space R may be directly detected by a pressure sensor provided in the wafer chuck 34 or the head stage 30, for example, or may be detected by a pressure sensor built into or connected to the pressure reducing regulator 54.

[0085] (Step S24: Wafer chuck release process) Next, the chuck fixing solenoid valve control unit 112 turns the chuck fixing solenoid valve 84 OFF (closed state) and releases the fixing of the wafer chuck 34 by the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72 (time T9 in FIG. 11).

[0086] At this time, since the internal pressure of the internal space R is adjusted to the set pressure by the pressure reducing regulator 54, when the fixation of the wafer chuck 34 by the Z-axis moving and rotating unit 72 is released, the wafer chuck 34 is detached from the Z-axis moving and rotating unit 72 and is attracted toward the probe card 32 (T9 to T10 in FIG. 11). As a result, the electrode pads of each chip of the wafer W to be inspected and each probe 36 of the probe card 32 are reliably contacted with each other at a predetermined contact pressure, without being affected by the inclination of the wafer W and the arrangement surface of the tips of the probes 36 and the variation in the tip positions of the probes 36.

[0087] In this manner, in the present embodiment, the fixation of the wafer chuck 34 is released after depressurization of the internal space R has begun, so that at the moment of switching between these processes, the wafer chuck 34 is no longer in a state where it is not fixed to either side (a free state), and the transfer operation of the wafer chuck 34 can be performed stably.

[0088] In this embodiment, the suction path connecting the suction path 82 of the Z-axis moving / rotating part 72 and the chuck fixing solenoid valve 84 is provided with a throttle valve 86, so that even if the wafer chuck 34 is released from the fixed position after the internal space R is depressurized, the negative pressure on the lower side (the Z-axis moving / rotating part 72 side) of the wafer chuck 34 is not suddenly lost. Therefore, the wafer chuck 34 is not suddenly restrained from the lower side (i.e., the fixing force due to suction from the Z-axis moving / rotating part 72) in a state where the wafer chuck 34 is pulled from both the upper and lower sides (i.e., both sides of the Z-axis moving / rotating part 72 and the probe card 32), so that abnormal vibrations and abnormal contacts caused by the sudden movement of the wafer chuck 34 can be reduced. Therefore, the wafer chuck 34 can be prevented from suddenly coming off the Z-axis moving / rotating part 72 when the wafer chuck fixing release step is performed, so that the wafer chuck 34 can be transferred more stably.

[0089] In this embodiment, as an example, a configuration has been shown in which a throttle valve 86 is provided in the suction path connecting the suction path 82 of the Z-axis moving / rotating unit 72 and the chuck fixing solenoid valve 84. However, it is sufficient that the throttle valve 86 is provided in the path connecting the suction port 80 of the Z-axis moving / rotating unit 72 and the suction device 44. For example, the throttle valve 86 may be provided in the suction path 82 of the Z-axis moving / rotating unit 72.

[0090] (Step S26: Z-axis lowering process) Next, as shown in FIG. 10(E), the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to lower the Z-axis movement / rotation unit 72 to a predetermined height position (standby position) (times T11 to T12 in FIG. 11).

[0091] When the wafer chuck 34 is transferred from the alignment device 70 (Z-axis moving / rotating unit 72) to the head stage 30 (probe card 32 side) in the above manner, each probe 36 of the probe card 32 comes into contact with the electrode pad of each chip on the wafer W with uniform contact pressure, and the wafer-level inspection is ready to begin. After that, power and test signals are supplied from the test head to each chip on the wafer W via each probe 36, and an electrical operation inspection is performed by detecting the signal output from each chip.

[0092] After the wafer chuck 34 is transferred from the alignment device 70 (Z-axis movement / rotation section 72) to the head stage 30 (probe card 32 side), the alignment device 70 moves to another measurement section 16, where a contact operation is performed in a similar procedure, and wafer-level inspections are performed sequentially.

[0093] This completes the contact operation in the prober 10 according to the first embodiment.

[0094] Next, a release operation (one example of a probe inspection method) performed after the wafer-level inspection is completed in the prober 10 of the first embodiment will be described with reference to FIGS.

[0095] Fig. 12 is a flowchart showing the release operation in the prober 10 of the first embodiment. Fig. 13 is a diagram for explaining the release operation in the prober 10 of the first embodiment. Fig. 14 is a timing chart showing the release operation in the prober 10 of the first embodiment.

[0096] (Step S30: Z-axis rising process) First, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to raise the Z-axis movement / rotation unit 72 from a predetermined height position to a height position (chuck receiving height) at which the wafer chuck 34 can be received, as shown in FIG. 13(A) (times T1 to T2 in FIG. 14).

[0097] 13A, when the Z-axis moving / rotating unit 72 is raised to the chuck receiving height and the wafer chuck 34 is moved to the release position, the positional relationship between the wafer chuck 34 and the Z-axis moving / rotating unit 72 is preferably such that the positioning pin 88 is not engaged with the V-block (positioning groove) 90 and the ring-shaped seal member 78 is in contact with the bottom surface of the wafer chuck 34. By bringing the ring-shaped seal member 78 into contact with the bottom surface of the wafer chuck 34 before the chuck release step described later is performed, the ring-shaped seal member 78 can effectively absorb the impact when the wafer chuck 34 is released.

[0098] (Step S32: Chuck release process) Next, the shutter control unit 116 controls the shutter means 58 to open the communication passage 56. As a result, air flows from the external space into the internal space R, the pressure in the internal space R increases, and the wafer chuck 34 is released (time T4 in FIG. 14).

[0099] In this embodiment, in order to prevent damage to the wafer W and the probes 36, it is necessary to minimize the time that the wafer chuck 34 is in an unstable state, and for this purpose, it is desirable that the release speed of the wafer chuck 34 is sufficiently faster than the case where the internal space R is opened to the atmosphere or a small pressure is applied to break the vacuum. Therefore, although the target release speed differs depending on the types of the probe card 32, the probes 36, and the wafer W, it has been confirmed through experiments that a speed of 10 mm / sec or more is preferable, for example.

[0100] In this embodiment, the effective cross-sectional area of ​​the communication path 56 is adjusted so that the wafer chuck 34 is released at a preset target release speed from the probe card 32. A method for calculating the effective cross-sectional area of ​​the communication path 56 will be described below.

[0101] The moving distance when the wafer chuck 34 is released is y (mm), the speed when the wafer chuck 34 is released is v (mm / sec), and the area of ​​the region surrounded by the ring-shaped seal member 48 (hereinafter referred to as the seal area) is A (mm 2 ), the load applied to the wafer chuck 34 from the probe card 32 is F (kgf) (proper OD position), the weight of the wafer chuck 34 is m (kgf), and the temperature is t (° C.) (maximum operating temperature).

[0102] Then, the change in volume of the internal space R when the wafer chuck 34 is released is A×y (mm 3 ), and the time required to release the wafer chuck 34 is expressed as y / v (sec). Note that the acceleration required to reach the velocity v when the wafer chuck 34 is released is not taken into consideration here.

[0103] When the wafer chuck 34 is released, the flow rate (maximum flow rate) Q of the air flowing into the internal space R surrounded by the wafer chuck 34, the probe card 32, and the ring-shaped seal member 48 per unit time is calculated by the following formula (1).

[0104]

number

[0105] On the other hand, the chucking pressure P of the wafer chuck 34 is calculated by the following formula (2): Here, g is the gravitational acceleration.

[0106] P = -(F + m) × g / A (MPa) … (2) If it is assumed that the air flow from the external space to the internal space R is a subsonic flow slower than the speed of sound at any point, the effective cross-sectional area S of the communication passage 56 is calculated by the following formula (3).

[0107]

number

[0108] As an example, y = 400 μm, v = 10 mm / sec, A = 106940 mm 2 , F = 20 kgf (value at 100 μm from the proper OD position), m = 10 kgf, t = 150 °C, S = 20 mm 2 Therefore, in this case, in order to make v≧10mm / sec, the necessary effective cross-sectional area S is S≧20mm 2 It becomes.

[0109] Under the above conditions, the relationship between the chuck release speed and the required effective cross-sectional area is as shown in the graph in Fig. 15. As shown in Fig. 15, there is, for example, a certain correlation (proportional relationship) between the release speed of the wafer chuck 34 and the effective cross-sectional area of ​​the communicating passage 56. This relationship (release speed-effective cross-sectional area characteristics) can be obtained in advance by experiment. Therefore, the effective cross-sectional area S of the communicating passage 56 can be obtained from the target release speed using the previously obtained release speed-effective cross-sectional area characteristics. Note that the release speed-effective cross-sectional area characteristics differ depending on the individual prober, and are preferably obtained for each prober.

[0110] In the example shown in FIG. 6, four of the communication passages 56 are provided in parallel on the periphery of the wafer chuck 34. In this case, the combined effective cross-sectional area S is the effective cross-sectional area S i If (i=1 to n, n=4), it can be calculated by the following formula (4).

[0111] S=S1+S2+…+S n …(4) Here, the effective cross-sectional area S of each communication passage 56 i It is preferable to make the effective cross-sectional area S i In order to prevent the wafer chuck 34 from being tilted during release due to the pressure distribution in the internal space R, for example, the effective cross-sectional areas S of the communication paths 56 located opposite to the center of the wafer chuck 34 of each communication path 56 may be set to be equal to each other. i In other words, the effective cross-sectional area S of the communication passages 56 located at point symmetric positions with respect to the center of the wafer chuck 34 should be equal to each other.i may be set to be equal.

[0112] As a result, the wafer chuck 34 is released from the probe card 32 at a sufficiently fast release speed. Then, the wafer chuck 34 released from the probe card 32 is supported by the Z-axis moving and rotating portion 72.

[0113] After the wafer chuck 34 is released, the chuck fixing solenoid valve control unit 112 turns on (open state) the chuck fixing solenoid valve 84 and fixes the wafer chuck 34 via the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72 (time T5 in FIG. 14). Note that suction (application of negative pressure) by the suction port 80 may be started before the wafer chuck 34 is released. By setting the space between the alignment device 70 and the wafer chuck 34 to a negative pressure lower than atmospheric pressure before the wafer chuck 34 is released, the release speed of the wafer chuck 34 can be improved.

[0114] (Step S34: Z-axis lowering process) Next, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to lower the Z-axis moving / rotating unit 72 as shown in Fig. 13(C), thereby changing the wafer chuck 34 to a predetermined height position (standby height position) (times T6 to T7 in Fig. 14). In step S34, the communication passage 56 may be closed by the shutter means 58.

[0115] This completes the release operation in the prober 10 according to the first embodiment.

[0116] Next, the effects of the first embodiment will be described.

[0117] In the release operation in the first embodiment, the pressure control unit 115 adjusts the effective cross-sectional area of ​​the communication passage 56 so that the wafer chuck 34 is released from the probe card 32 side at a target release speed. This allows the wafer chuck 34 to be released from the probe card 32 side at a release speed that is sufficiently faster than when the internal space R is opened to the atmosphere or a small pressure is applied to break the vacuum. As a result, the time that the wafer chuck 34 is in an unstable state can be eliminated, making it possible to prevent damage to the wafer W and the probes 36.

[0118] In the contact operation in the first embodiment, the Z-axis moving / rotating unit 72 moves the wafer chuck 34 up and down (Z direction), thereby bringing the electrode pads on the wafer W into contact with the probes 36 in an overdrive state. The Z-axis moving / rotating unit 72 is configured with a mechanical drive mechanism including at least a motor (Z-axis driving motor 122), so that it is possible to precisely adjust the moving distance and moving speed of the wafer chuck 34. The Z-axis moving / rotating unit 72 can move the wafer chuck 34 at a moving speed that is sufficiently faster than the contact operation by the vacuum suction method as in the conventional technology. Therefore, when the electrode pads on the wafer W are brought into contact with the probes 36, it is possible to remove the oxide film (insulator) on the electrode pads by the contact of the probes 36, and good contact can be achieved between the electrode pads on the wafer W and the probes 36 without damaging the wafer W.

[0119] In the first embodiment, the wafer chuck 34 is released from the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72 at a timing (second timing; time T9 in FIG. 11) later than the timing (first timing; time T7 in FIG. 11) at which the pressure reduction of the internal space R is started, so that the wafer chuck 34 is not fixed to either side at the moment of switching between these processes (an unstable state (free state)) and the wafer chuck transfer operation can be stably performed. The above control is realized by the pressure control unit 115 and the chuck fixing solenoid valve control unit 112 controlling in cooperation with each other under the control of the overall control unit 100 functioning as the timing control means of the present invention.

[0120] In the first embodiment, the shutter opening step (step S12) is performed at least before the ring-shaped seal member 48 of the wafer chuck 34 comes into contact with the head stage 30 (see FIG. 10(B)). That is, in the Z-axis lifting step (step S14), from the state in which the ring-shaped seal member 48 comes into contact with the head stage 30 (see FIG. 10(B)) until the wafer chuck 34 is further lifted (see FIG. 10(C)), the internal space R is in a communicated state (non-sealed state) in which it communicates with the external space via the communication path 56.

[0121] Here, if the wafer chuck 34 is attempted to be raised by the Z-axis moving / rotating unit 72 in a closed state (sealed state) in which the internal space R is not in communication with the external space, the air in the internal space R is instantaneously compressed as the wafer chuck 34 is raised, generating a strong reaction force, which may vibrate the head stage 30 and cause the probe card 32 and the wafer W to come into contact in an unintended manner. In this case, the abnormal contact between the probe card 32 and the wafer W may damage the probe card 32 and the wafer W.

[0122] In contrast, in the first embodiment, as described above, the Z-axis moving / rotating unit 72 raises the wafer chuck 34 in a connected state (non-sealed state) in which the internal space R is connected to the external space. Therefore, no excessive reaction force (a reaction force attempting to return the wafer chuck 34 to its original position) is generated when raising the wafer chuck 34, and the wafer chuck 34 can be raised stably and efficiently, thereby preventing damage to the probe card 32 and the wafer W.

[0123] Furthermore, in the first embodiment, a throttle valve 86 for limiting the flow rate of gas is provided in the path connected to the suction port 80 of the Z-axis moving / rotating section 72. This makes it possible to prevent the wafer chuck 34 from suddenly detaching from the Z-axis moving / rotating section 72 when the chuck fixing solenoid valve 84 is turned OFF (when open to the atmosphere), thereby making it possible to perform the transfer operation of the wafer chuck 34 more stably.

[0124] Second embodiment Next, a second embodiment will be described. Below, the description will be omitted for the parts common to the above-mentioned embodiment, and the description will focus on the characteristic parts of this embodiment.

[0125] In the contact operation in the first embodiment, the fixation of the wafer chuck 34 by the Z-axis moving / rotating unit 72 is released at a timing later than the timing when the decompression of the internal space R is started, and when the fixation of the wafer chuck 34 is released, the wafer chuck 34 is detached from the Z-axis moving / rotating unit 72, and the wafer chuck 34 moves toward the probe card 32 as if being attracted to it. At this time, the movement of the wafer chuck 34 in the horizontal direction (X, Y directions) is restricted only by the contact pressure between the electrode pads on the wafer W and the probes 36 (i.e., the needle pressure of the probe card 32). Therefore, if the wafer chuck 34 is subjected to an external disturbance such as vibration during the decompression process, the wafer chuck 34 is likely to be misaligned or tilted in the horizontal direction, and there is a possibility that the wafer chuck 34 will not rise straight in the vertical direction (Z direction).

[0126] The release operation in the first embodiment also has a similar problem. That is, when the wafer chuck 34 is released from the probe card 32 side by pressurizing the internal space R, the movement of the wafer chuck 34 in the horizontal direction (X, Y directions) is restricted only by the contact pressure between the electrode pads on the wafer W and the probes 36 (i.e., the needle pressure of the probe card 32). Therefore, if the wafer chuck 34 is subjected to an external disturbance such as vibration when it is released, the wafer chuck 34 is likely to be displaced or tilted in the horizontal direction, and the wafer chuck 34 may not descend straight in the vertical direction (Z direction).

[0127] Therefore, in the second embodiment, in order to improve stability against disturbances in the contact operation and release operation of the wafer chuck 34, the following configuration is provided.

[0128] FIG. 16 is a schematic diagram showing the configuration of a prober 10 according to the second embodiment.

[0129] 16, the prober 10 according to the second embodiment includes a chuck guide mechanism 200 that guides the wafer chuck 34 in the Z direction (vertical direction) as a configuration for improving stability against disturbances during contact and release operations of the wafer chuck 34. The chuck guide mechanism 200 is an example of a guide means.

[0130] A plurality of chuck guide mechanisms 200 are provided in parallel along the circumferential direction of the peripheral portion of the wafer chuck 34, specifically, the outer periphery of the chuck guide holding portion 35 integrated with the wafer chuck 34. The chuck guide mechanism 200 functions as a guide mechanism that restricts the horizontal movement of the wafer chuck 34 while moving it parallel to the Z direction by vacuum-adsorbing and fixing a chuck guide 204 (described later) to the head stage 30 before the contact operation or release operation of the wafer chuck 34 is performed. For this reason, at least three chuck guide mechanisms 200 are provided on the wafer chuck 34 (chuck guide holding portion 35) at different positions in the horizontal direction (X and Y directions) perpendicular to the moving direction (Z direction) of the wafer chuck 34. Although not shown in the figure in this example, four chuck guide mechanisms 200 are provided on the chuck guide holding portion 35 at equal intervals (every 90 degrees) along the circumferential direction (only two are shown in FIG. 16).

[0131] Here, the configuration of the chuck guide mechanism 200 will be described in detail.

[0132] The chuck guide mechanism 200 has a bearing portion 202 formed in the chuck guide holding portion 35, and a chuck guide (guide shaft portion) 204 configured to be movable in the Z direction (vertical direction) while movement in the X and Y directions (horizontal directions) is restricted by the bearing portion 202. The bearing portion 202 is configured of, for example, a ball bearing.

[0133] The chuck guide 204 is rotatably supported by the bearing portion 202, and a fixed portion 206 for detachably fixing the chuck guide 204 to the head stage 30 is provided at its upper portion. A ring-shaped seal member (hereinafter referred to as "chuck guide seal rubber") 208 is provided on the upper surface of the fixed portion 206, and a suction port (not shown) connected to a suction path (not shown) and a clearance retaining member 210 for maintaining a constant distance (gap) between the fixed portion 206 and the head stage 30 are provided on the inside of the chuck guide seal rubber 208. The shape of the clearance retaining member 210 is not particularly limited as long as it can maintain a constant gap between the fixed portion 206 and the head stage 30.

[0134] Next, a contact operation (one example of a probe inspection method) in the prober 10 according to the second embodiment will be described. Fig. 17 is a diagram for explaining the contact operation in the prober 10 according to the second embodiment.

[0135] First, in the same manner as in the first embodiment, the wafer chuck fixing step, the alignment step, and the shutter opening step are performed in order, and then the Z-axis raising step is performed.

[0136] In the Z-axis lifting step, the Z-axis moving / rotating unit 72 moves (lifts) the wafer chuck 34 toward the probe card 32, whereby, as shown in Fig. 17(A), the probes 36 of the probe card 32 come into contact with the electrode pads of the chips on the wafer W in an overdrive state. At this time, the chuck guide seal rubber 208 comes into contact with the underside of the head stage 30 as the wafer chuck 34 moves toward the probe card 32.

[0137] Next, when the internal space Q formed inside the chuck guide seal rubber 208, the head stage 30, and the fixed part 206 is depressurized by the suction device 44 through a suction port and a suction path (not shown), the chuck guide 204 rises upward (toward the head stage 30) and the fixed part 206 of the chuck guide 204 is fixed by suction to the head stage 30 (see FIG. 17(B)). At this time, the above-mentioned clearance holding member 210 ensures a certain gap between the head stage 30 and the fixed part (suction part) 206 of the chuck guide 204, so that excessive suction by the fixed part (suction part) 206 of the chuck guide 204 is suppressed, and the inclination of the chuck guide 204 fixed to the head stage 30 can be prevented.

[0138] After the chuck guide 204 has been fixed to the head stage 30 by suction in this manner, the shutter closing step, the depressurizing step, and the determining step are carried out in sequence, as in the first embodiment, and then the wafer chuck release step is carried out.

[0139] In the wafer chuck fastening release process, when the fastening of the wafer chuck 34 by the Z-axis moving / rotating unit 72 is released, the wafer chuck 34 separates from the Z-axis moving / rotating unit 72 and moves so as to be attracted toward the probe card 32 by the reduced pressure in the internal space R. At this time, the wafer chuck 34 moves while being guided in the Z direction by the chuck guide 204 fixed to the head stage 30 while its movement in the X and Y directions is restricted (see FIG. 17(C)).

[0140] This completes the contact operation in the prober 10 according to the second embodiment.

[0141] Next, a release operation (one example of a probe inspection method) in the prober 10 according to the second embodiment will be described. Fig. 18 is a diagram for explaining the release operation in the prober 10 according to the second embodiment.

[0142] First, in the same manner as in the first embodiment, the Z-axis raising step is performed, and then the chuck release step is performed.

[0143] In the chuck release step, the shutter control unit 116 controls the shutter means 58 to open the communication passage 56. This causes air to flow from the external space into the internal space R, increasing the pressure in the internal space R, and the wafer chuck 34 is released from the probe card 32 side at a sufficiently fast release speed. At this time, as shown in FIG. 18(B), the wafer chuck 34 is guided downward in the Z direction while its movement in the X and Y directions is restricted by the chuck guide 204, and is supported by the Z-axis moving / rotating unit 72.

[0144] Thereafter, the chuck fixing solenoid valve control unit 112 turns the chuck fixing solenoid valve 84 ON (open state) to fix the wafer chuck 34 via the suction port 80 of the Z-axis moving / rotating unit 72 (see FIG. 4).

[0145] Next, as a chuck guide release process, the internal space Q formed inside the chuck guide seal rubber 208, the head stage 30, and the fixed part 206 is opened to the atmosphere or vacuum-destroyed by applying a small amount of pressure. This releases the adhesion of the chuck guide 204 to the head stage 30, as shown in FIG. 18(C).

[0146] Thereafter, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to lower the Z-axis movement / rotation unit 72.

[0147] This completes the release operation in the prober 10 according to the second embodiment.

[0148] As described above, according to the second embodiment, the chuck guide mechanism 200 is provided for guiding the wafer chuck 34 in the Z direction along the chuck guide 204 with the chuck guide 204 (fixing portion 206) fixed to the head stage 30 by vacuum suction, so that it is possible to prevent the wafer chuck 34 from shifting or tilting when transferring the wafer chuck 34 in the contact operation or release operation of the wafer chuck 34. Therefore, it is possible to prevent tilting or shifting due to an uneven load due to the components of the wafer chuck 34, and it is possible to stably transfer the wafer chuck 34 while maintaining the parallelism between the probe card 32 and the wafer W, and it is possible to achieve good contact between the electrode pads on the wafer W and the probes 36.

[0149] In the second embodiment, a vacuum suction fixing method is shown as a fixing method for the chuck guide mechanism 200, but various well-known methods can be used as long as the chuck guide 204 can be detachably fixed to the head stage 30, and a mechanical method using a clamp or the like may also be used.

[0150] In addition, in the second embodiment, a configuration is shown in which the chuck guide mechanism 200 is provided on the wafer chuck 34 side and the chuck guide 204 (fixed portion 206) is adsorbed to the head stage 30 side, but a configuration in which the chuck guide mechanism 200 is provided on the head stage 30 side and the chuck guide 204 (fixed portion 206) is adsorbed to the wafer chuck 34 side may also be used.

[0151] The prober and the probe inspection method according to the present invention have been described in detail above. However, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0152] 10... prober, 12... measurement unit, 14... loader section, 16... measurement section, 18... load port, 20... card stocker, 22... operation panel, 24... transport unit, 26... transport arm, 30... head stage, 32... probe card, 34... wafer chuck, 34a... wafer holding surface, 36... probe, 40... suction port, 42... suction path, 44... suction device, 46... solenoid valve for wafer suction, 48... ring-shaped seal member, 50... pressure supply port, 52... supply path, 54... pressure reducing regulator, 56... communication path, 58... shutter means, 60... piping, 70... alignment device, 72... Z-axis moving / rotating section, 72a... wafer chuck support surface, 74... X-axis moving stage, 76... Y-axis moving stage, 78... ring-shaped seal member, 80... suction port, 82... suction path, 84... solenoid valve for chuck fixation, 86... throttle valve, 88...positioning pin, 90...V-block, 100...overall control unit, 102...X-axis movement control unit, 104...Y-axis movement control unit, 106...Z-axis movement control unit, 108...θ rotation control unit, 110...wafer suction solenoid valve control unit, 112...chuck fixing solenoid valve control unit, 115...pressure control unit, 116...shutter control unit, 118...X-axis drive motor, 120...Y-axis drive motor, 122...Z-axis drive motor, 124...rotation drive motor, 200...chuck guide mechanism, 202...bearing unit, 204...chuck guide, 206...fixed unit, 208...chuck guide seal rubber, 210...clearance retaining member, 300...air cylinder mechanism, 302...opening / closing valve, 304...cylinder, 306...piston, 308...piston rod, 310...air cylinder drive unit, W...wafer, R...internal space, Q...internal space

Claims

1. A wafer chuck for holding the wafer; a probe card having a plurality of probes on a surface facing the wafer chuck; a seal member that forms an internal space between the wafer chuck and the probe card; a communication passage that communicates between the internal space and the external space, the communication passage having an effective cross-sectional area capable of ensuring a flow rate of air required for releasing the wafer chuck, which is attracted and held on the probe card side, at a target release speed by air flowing from the external space into the internal space when the internal space is switched to an unsealed state; A prober comprising:

2. When the wafer chuck is released from the probe card side, the internal space is switched from a sealed state to an unsealed state.

2. The prober according to claim 1.

3. A probe inspection method for inspecting a wafer held by a wafer chuck by suction on a probe card, comprising the steps of: a step of opening a communication passage that communicates between an internal space formed between the wafer chuck and the probe card and an external space when the wafer chuck is released from the probe card side, thereby making the internal space unsealed; a probe inspection method in which the communicating passage has an effective cross-sectional area capable of ensuring a flow rate of air required for releasing the wafer chuck, which is adsorbed and held on the probe card side, at a target release speed by air flowing from the external space into the internal space when the internal space is switched to an unsealed state.

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