Prober

Abstract

To provide a prober capable of delivering a wafer chuck to an alignment device at an appropriate position even after the wafer chuck has separated from the lower surface of a measuring portion and is temporarily held by a fall prevention mechanism.SOLUTION: A prober includes a measurement unit, a wafer chuck, an alignment device, and a fall prevention mechanism. The wafer chuck holds a wafer on its upper surface and is held on the lower surface of the measurement unit. The fall prevention mechanism prevents the wafer chuck from falling from the lower surface of the measurement unit. The fall prevention mechanism includes multiple fall prevention claws and a position control device. The position control device can switch the positions of the multiple fall prevention claws between a retracted position that allows the wafer chuck to pass between the fall prevention claws, an intermediate position that receives the wafer chuck at its bottom when it moves away from the lower surface of the measurement unit, and an advanced position that centers the wafer chuck.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a prober for inspecting the electrical characteristics of semiconductor devices (chips) formed on a semiconductor wafer. [Background technology]

[0002] The semiconductor manufacturing process involves many steps, and multiple types of inspections are performed at each manufacturing step to ensure quality and improve yield. For example, at the stage where multiple chips, which are semiconductor devices, are formed on a semiconductor wafer (hereinafter simply referred to as a "wafer"), wafer-level inspection is performed in which the electrodes of each chip are connected to a test head, a power supply current and a test signal are supplied from the test head, and the signals output by each chip are measured by the test head to electrically inspect whether they are operating normally.

[0003] After the wafer-level inspection described above, the wafer is attached to a frame and cut into individual chips using a dicer. Of the cut chips, only those that are confirmed to be functioning properly are packaged in the next assembly process, while chips that are not functioning properly are removed from the assembly process. The packaged final product then undergoes shipping inspection.

[0004] Wafer-level testing is performed using a prober that contacts probes with the electrodes of each chip on the wafer. The probes that contact the electrodes are attached to a probe card that is attached to the test head. The probes are electrically connected to the terminals of the test head. Power supply current and test signals supplied from the test head are input to each chip through the probes, and output signals from each chip are output to the test head through the probes. The test head measures the signals output from each chip and determines whether the chip is operating normally based on the measurements.

[0005] A known prober used in wafer-level inspection uses a wafer chuck (wafer tray) that holds the wafer on its upper surface and is vacuum-adsorbed to the underside of the ceiling wall of the housing (the underside of the measurement section) (see, for example, Patent Documents 1 and 2).

[0006] This prober uses vacuum suction to hold a wafer chuck holding a wafer to be tested against the underside of the ceiling wall of the housing, pressing the electrodes on the wafer against the corresponding probes on the probe card and maintaining a connection between each probe and the corresponding electrode. Because this prober can maintain a connection between the wafer and the probe card using only the wafer chuck, there is no need to maintain an alignment device below the measurement unit that positions the wafer and probe card via the wafer chuck and transports the wafer chuck. This means that the alignment device can be shared with other measurement units.

[0007] Furthermore, in the case of this type of prober in which the wafer chuck is held to the ceiling wall of the housing by vacuum suction, there is a concern that the wafer chuck may fall downward if the power is turned off while the wafer chuck is still attached.

[0008] For this reason, the probers described in the cited documents 1 and 2 are provided with a fall prevention mechanism that mechanically prevents the wafer chuck from falling. This fall prevention mechanism is provided with a hook member on either the wafer chuck or the ceiling wall of the housing, which is mechanically engageable with the other. In this prober, the wafer chuck is vacuum-sucked and the hook member is displaced to a position where it can engage with a mating member, thereby preventing the wafer chuck from falling in the unlikely event of an accident. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2011 / 016097 [Patent Document 2] Japanese Patent Publication No. 2020-113701 Summary of the Invention [Problem to be solved by the invention]

[0010] The probers described in Patent Documents 1 and 2 can prevent the wafer chuck from falling by a fall prevention mechanism even if the wafer chuck attached to the ceiling wall separates from the ceiling wall due to power OFF, etc. However, when the wafer chuck is transferred from this state to an engagement part of an alignment device, the position of the wafer chuck may shift with respect to the engagement part of the alignment device, which is waiting in the correct position.

[0011] In this case, the alignment device must detect the position of the wafer chuck using a camera or the like mounted on the device and adjust the position of the engagement part to match the detected position. However, if there is a large deviation between the position of the engagement part of the alignment device and the position of the wafer chuck, it takes a long time to detect the position of the wafer chuck and adjust the position of the alignment device. This is undesirable from the perspective of improving throughput, and an early improvement is desired.

[0012] Therefore, the present invention aims to provide a prober that can transfer the wafer chuck to an alignment device in the correct position even after the wafer chuck has separated from the underside of the measurement section and is temporarily held by a drop prevention mechanism. [Means for solving the problem]

[0013] a position control device that controls the advance / retract positions of the plurality of drop-control claws, and the position control device is capable of switching the positions of the plurality of drop-control claws between a retreated position that allows the wafer chuck to pass between the drop-control claws, an intermediate position that receives the wafer chuck from below when the wafer chuck moves away from the underside of the measurement unit, and an advanced position that centers the wafer chuck.

[0014] In the prober of this embodiment, when the plurality of drop-control claws are operated to the retracted position under the control of the position control device, the wafer chuck can pass between the plurality of drop-control claws. In this state, the alignment device can raise and lower the wafer chuck and adjust its position. In this state, the alignment device adjusts the position of the wafer chuck holding a wafer on its upper surface, and then the alignment device raises the wafer chuck. Thereafter, the wafer chuck is vacuum-sucked and fixed to the lower surface of the measurement unit. Thereafter, the plurality of drop-control claws are operated to an intermediate position under the control of the position control device. As a result, even if the wafer chuck attracted to the measurement unit is separated from the measurement unit due to, for example, being turned off, the wafer chuck will be received below by the plurality of drop-control claws. Furthermore, when the plurality of drop-control claws are operated from this state to the forward position under the control of the position control device, the plurality of drop-control claws will center the wafer chuck. As a result, the positional deviation of the wafer chuck from the alignment device below is corrected. Thereafter, when the alignment device is raised, the wafer chuck is delivered to the alignment device at the appropriate position.

[0015] The outer peripheral edge of the wafer chuck may be formed in a circular shape concentric with the wafer held on the upper surface of the wafer chuck, and each of the drop-control claws may move back and forth along the radial direction of the wafer chuck.

[0016] In this case, the drop prevention claws move forward and backward along the radial direction of the wafer chuck, so that they can move forward and backward in the shortest distance without loss relative to the underside of the wafer chuck. Also, when the drop prevention claws are displaced to the forward position, they can quickly center the wafer chuck.

[0017] It is desirable that two or more of the fall-regulating claws be provided spaced apart from each other in the outer circumferential direction of the wafer chuck.

[0018] In this case, by displacing two or more fall-regulating claws to the forward position, it becomes possible to easily and accurately center the wafer chuck.

[0019] Each of the fall prevention claws may comprise a horizontal support surface capable of supporting the underside of the outer peripheral edge of the wafer chuck, and a control wall rising from the end of the support surface on the side away from the axial center position of the wafer chuck, and the surface of the control wall facing the outer peripheral edge of the wafer chuck may be made to be a centering surface that abuts against the outer peripheral edge of the wafer chuck when the fall prevention claw is in the advanced position.

[0020] In this case, when the wafer chuck moves away from the underside of the measuring unit while the fall prevention claws are in the intermediate position, the outer periphery of the wafer chuck rests on the support surface of the fall prevention claws. When the fall prevention claws are displaced from this state to the advanced position, the centering surface of the upright wall abuts on the outer periphery of the wafer chuck. As a result, the wafer chuck is centered by the centering surface while remaining placed on the support surface of the fall prevention claws. Therefore, when this configuration is adopted, the wafer chuck can be displaced to the appropriate position while maintaining a stable posture.

[0021] The centering surface may be configured as an inclined surface that slopes downward toward the axis of the wafer chuck.

[0022] In this case, even if the wafer chuck is significantly deviated from the proper position when it separates from the underside of the measuring unit, the lowered wafer chuck abuts against the inclined centering surface and is guided by the centering surface to the vicinity of the proper position. As a result, when the fall-regulating claws are displaced to the forward position, the wafer chuck is reliably centered by the centering surface. [Effects of the Invention]

[0023] According to the prober of the present invention, even after the wafer chuck has separated from the lower surface of the measurement unit and is temporarily held by the fall prevention mechanism, the wafer chuck can be delivered to the alignment device in the correct position. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 2 is a partial cross-sectional front view showing a state before a wafer chuck is mounted in the wafer inspection apparatus according to the embodiment. [Figure 2] FIG. 1 is a perspective view showing a schematic configuration of an alignment apparatus according to an embodiment. [Figure 3] FIG. 4 is a bottom view of the measuring unit and wafer chuck according to the embodiment. [Figure 4] 4 is an enlarged view of a portion of FIG. 3 when the fall-control claw is in a retracted position. [Figure 5] FIG. 10 is a circuit diagram of the fluid control unit showing a state when the three-position control device of the embodiment controls the fall-restriction pawl to a retracted position. [Figure 6] FIG. 2 is a partial cross-sectional front view showing a state in which a wafer chuck is attached to the wafer inspection device according to the embodiment. [Figure 7] 4 is an enlarged view of a portion of FIG. 3 when the fall-prevention claw is in an intermediate position. [Figure 8] FIG. 10 is a circuit diagram of the fluid control unit showing a state when the fall-prevention claw is controlled to an intermediate position. [Figure 9] FIG. 10 is a partial cross-sectional front view showing a state in which the fall of the wafer chuck of the wafer inspection device according to the embodiment is restricted. [Figure 10] FIG. 2 is a partial cross-sectional front view showing a state in which the wafer chuck of the wafer inspection device according to the embodiment is centered. [Figure 11] 4 is an enlarged view of a portion of FIG. 3 when the fall-control claw is in a forward position. [Figure 12] FIG. 10 is a circuit diagram of the fluid control unit showing a state when the fall-restricting claw is controlled to the forward position. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, arrows X, Y, and Z indicating a Cartesian coordinate system are written in appropriate places in the drawings. Arrow Z of the Cartesian coordinate system points vertically upward, arrow X points in a direction perpendicular to the Z direction, and arrow Y points in a direction perpendicular to the Z and X directions.

[0026] FIG. 1 is a partial cross-sectional front view of a wafer inspection device 1 according to an embodiment. The wafer inspection device 1 constitutes part of a system for performing wafer-level inspection. The wafer inspection device 1 includes a prober 11 that brings probes into contact with electrodes of each chip on the wafer W, and a test head 12 that is electrically connected to the probes and supplies a power supply current and a test signal to each chip to measure signals output from each chip. The test head 12 is a device for performing electrical inspection on each chip, and determines whether the chip operates normally based on measurements of the signals output from each chip.

[0027] The housing 13 of the wafer inspection device 1 has side walls 14 and a ceiling wall 15. The ceiling wall 15 forms a head stage on which a plurality of measurement units 16 are arranged. A prober 11 is disposed in each measurement unit 16. Although only one measurement unit 16 is shown on the ceiling wall 15 in FIG. 1, a plurality of measurement units 16 are provided in parallel on the ceiling wall 15 of the housing 13.

[0028] The prober 11 includes a probe card 18 having a large number of probes (not shown) corresponding to the electrodes of each chip on the wafer W, a wafer chuck 10 that holds the wafer W on its upper surface, and an alignment device 20 that detachably holds the wafer chuck 10 and aligns the wafer W and the probe card 18 via the wafer chuck 10. Each measurement unit 16 can simultaneously inspect all chips on the wafer W held on the wafer chuck 10. The alignment device 20 can be moved between the multiple measurement units 16 by a moving device (not shown). One alignment device 20 is shared by multiple probers 11. Furthermore, the test heads 12 corresponding to the respective measurement units 16 are attached to the upper part of the housing 13 via support walls 19 .

[0029] A card mounting section 21 (mounting hole) is provided in the ceiling wall 15 (head stage) of the housing 13 for each measurement section 16. A probe card 18 is replaceably disposed in each card mounting section 21. The probe card 18 is detachably attached to the underside of the corresponding test head 12 via a contactor 22. Each probe of the probe card 18 is electrically connected to a base within the test head 12 via the contactor 22. A wafer W to be inspected, held by a wafer chuck 10, is placed in a pressed state on the underside of the probe card 18.

[0030] The wafer chuck 10 is formed in a cylindrical shape with a short axis, with a ring-shaped flange wall 10f protruding upward from the outer circumferential surface of the main body 10a. The central region of the upper surface of the main body 10a is a mounting surface 10b on which a wafer W is placed. When the wafer W is placed on the mounting surface 10b, a positioning unit (not shown) positions the wafer W concentrically with the wafer chuck 10. A first suction port connected to a suction device (not shown) is formed in the mounting surface 10b. When a vacuum is drawn through the first suction port with the wafer W placed on the mounting surface 10b, the wafer W is adsorbed and fixed to the mounting surface 10b. This allows the wafer W to move and stop integrally with the wafer chuck 10. However, the means for fixing the wafer W to the mounting surface 10b is not limited to suction by vacuum suction, and the wafer W may be fixed to the mounting surface 10b by a mechanical mechanism.

[0031] The wafer chuck 10 is detachably held on the upper part of the alignment device 20 and is movable in the XYZ-θ directions by the alignment device 20. An engagement portion (not shown) is provided between the lower end of the main body 10a of the wafer chuck 10 and the chuck holding portion of the alignment device 20 to fix the relative positions of the two.

[0032] A sealing mechanism is provided on the upper part of the wafer chuck 10. The sealing mechanism includes a ring-shaped seal member 23 attached near the outer periphery of the upper surface of the wafer chuck 10, a second suction port (not shown) provided at a position away from the mounting surface 10b of the wafer chuck 10, and a suction device (not shown) connected to the second suction port. The second suction port is disposed at a position facing the inner periphery (radially inward) of the ring-shaped seal member 23.

[0033] When the wafer chuck 10 is held by the alignment device 20 and is pushed upward by the lifting unit of the alignment device 20, the ring-shaped sealing member 23 comes into contact with the underside of the ceiling wall 15 around the periphery of the probe card 18. Hereinafter, the portion of the underside of the ceiling wall 15 that comes into contact with the ring-shaped sealing member 23 will be referred to as the "chuck suction surface 15a."

[0034] In this state, when vacuum suction is performed through the second suction port, the internal space S (see FIG. 6) sealed by the ring-shaped seal member 23 is depressurized, and the wafer chuck 10 is drawn toward the ceiling wall 15 (probe card 18). As a result, the upper surface of the wafer W on the wafer chuck 10 is pressed against the probe card 18, and the multiple probes of the probe card 18 come into contact with and connect to the corresponding electrodes on the wafer W. The chuck holding portion of the alignment device 20 then retreats downward. In this embodiment, the ring-shaped seal member 23 is configured to contact the lower surface of the ceiling wall 15, but the ring-shaped seal member 23 may be configured to contact the peripheral edge of the lower surface of the probe card 18.

[0035] The chuck suction surface 15a on the lower surface of the ceiling wall 15 is formed to be recessed in a circular shape upward relative to its outer region. Hereinafter, the region of the lower surface of the ceiling wall 15 that is outer than the chuck suction surface 15a will be referred to as the "outer lower surface 15b," and the portion recessed upward between the outer lower surface 15b and the chuck suction surface 15a will be referred to as the "chuck accommodating portion 15c." The outer lower surface 15b of the ceiling wall 15 is provided with a plurality of drop prevention mechanisms 24 that prevent the wafer chuck 10 from falling from the lower surface of the ceiling wall 15 (measurement portion 16). The detailed structure of the fall prevention mechanism 24 will be described later.

[0036] 2 is a perspective view showing a schematic configuration of the alignment device 20. In addition, in FIG. 2, a state in which the wafer chuck 10 is held on the upper part of the alignment device 20 is shown. The alignment device 20 includes a movement / rotation mechanism 25 that moves the wafer chuck 10 in the X, Y, Z, and θ directions, and an alignment mechanism 26 that detects the relative positional relationship between the electrodes of each chip on the wafer W held on the wafer chuck 10 and the corresponding probes on the probe card 18. The alignment device 20 detects the relative positional relationship between the electrodes of each chip on the wafer W held on the wafer chuck 10 and the probes on the probe card 18 using the alignment mechanism 26, and based on the detection result, the movement / rotation mechanism 25 moves the wafer chuck 10 so that the electrodes of each chip come into contact with the probes.

[0037] The alignment device 20 includes a base table 27 connected to a moving device (not shown). The moving device moves between the multiple measurement units 16 by the operation of an actuator (not shown). A Y-axis moving stage 28, which is movable along the Y-axis direction, is supported on the base table 27. The Y-axis moving stage 28 can be moved to any position along the Y-axis direction by a Y-axis actuator 29 using a ball screw, a motor, or the like. An X-axis moving stage 30, which is movable along the X-axis direction, is supported on the Y-axis moving stage 28. The X-axis moving stage 30 can be moved to any position along the X-axis direction by an X-axis actuator 31 using a ball screw, a motor, or the like. A Z-axis moving / rotating unit 32, which has a chuck holding unit (not shown) on top, is installed on the X-axis moving stage 30. The wafer chuck 10 is releasably held by the chuck holding unit. The movement / rotation mechanism 25 is made up of a Z-axis movement / rotation unit 32, an X-axis movement stage 30, a Y-axis movement stage 28, and the like.

[0038] A probe position detection camera 33 is installed above the X-axis moving stage 30 via a camera moving mechanism 34. The probe position detection camera 33 detects the position of the probe on the probe card 18 at a position below the measurement unit 16. An alignment camera 35 is also installed on the base table 27 via a support 36. The imaging unit of the alignment camera 35 is arranged to face downward. The alignment camera 35 detects the position of the electrodes of each chip on the wafer W when the wafer chuck 10 holding the wafer W moves below the imaging unit by the operation of the Y-axis moving stage 28. The output units of the probe position detection camera 33 and the alignment camera 35 are connected to an image processing unit (not shown). The moving / rotating mechanism 25 adjusts the position of the wafer chuck 10 (wafer W) based on the image information detected by the probe position detection camera 33 and the alignment camera 35. The alignment mechanism 26 is composed of a probe position detection camera 33, an alignment camera 35, an image processing unit, and the like.

[0039] Next, the fall prevention mechanism 24 will be described. Fig. 3 is a bottom view of the measurement unit 16 and the wafer chuck 10, and Fig. 4 is an enlarged view of a part of Fig. 3. Fig. 5 is a circuit diagram showing a fluid control unit 42 of a three-position control device 37 (position control device) used in each fall prevention mechanism 24. As shown in Fig. 3, in this embodiment, four fall restriction mechanisms 24 are provided around the periphery of the chuck accommodating portion 15c on the underside of the ceiling wall 15 of the measuring unit 16. The four fall restriction mechanisms 24 are spaced apart at 90° intervals around the periphery of the chuck accommodating portion 15c. All four fall restriction mechanisms 24 have the same configuration. As shown in Figs. 3 and 4, each fall restriction mechanism 24 includes a fall restriction claw 38 that is provided on the outer underside 15b of the ceiling wall 15 so as to be able to move forward and backward, and a three-position control device 37 that controls the forward and backward position of the fall restriction claw 38. In this embodiment, four fall restriction mechanisms 24 are provided around the periphery of the chuck accommodating portion 15c, but the number of fall restriction mechanisms 24 is not limited to four. The number of fall restriction mechanisms 24 may be two or more. However, from the viewpoint of efficient centering of the wafer chuck 10, as will be described later, three or more is preferable. Furthermore, when two fall restriction mechanisms 24 are provided, the two fall restriction mechanisms 24 are preferably arranged at positions that are point-symmetric with respect to the axial center position o of the wafer chuck 10.

[0040] The fall-preventing claws 38 are attached to the outer lower surface 15b of the ceiling wall 15 so as to move back and forth along the radial direction of the circular chuck accommodating portion 15c of the ceiling wall 15. The outer peripheral edge portion of the flange wall 10f of the wafer chuck 10 accommodated in the chuck accommodating portion 15c is formed in a circular shape in a plan view. Therefore, it can be said that the fall-preventing claws 38 move back and forth along the radial direction of the wafer chuck 10.

[0041] Hereinafter, among the advancing and retreating positions of the fall prevention claw 38, the side close to the axial center position o of the wafer chuck 10 will be referred to as the "front" and the opposite side will be referred to as the "rear." The fall prevention claw 38 can be displaced and stopped at three positions, i.e., a retreated position, an intermediate position, and an advanced position, by position control by the three-position control device 37.

[0042] The retracted position is a position where the fall restriction claws 38 are retracted to the farthest rear. When the fall restriction claws 38 are in the retracted position, the tips of the fall restriction claws 38 are positioned radially outward of the chuck accommodating portion 15c. In this state, the wafer chuck 10 can be moved in and out of the chuck accommodating portion 15c in the vertical direction. In other words, the wafer chuck 10 is allowed to pass between the plurality of fall restriction claws 38 in the vertical direction.

[0043] The intermediate position is a position between the retracted position and the advanced position. When the fall-restricting claws 38 are in the intermediate position, the tips of the fall-restricting claws 38 are positioned at a position where they protrude a predetermined amount radially inward of the chuck accommodating portion 15c. In this state, when the wafer chuck 10, which is fixed by suction to the lower surface of the measuring portion 16, moves away from the measuring portion 16 due to the power being turned off or the like, the wafer chuck 10 can be received below (see FIG. 9).

[0044] The forward position is a position where the fall restriction claws 38 are advanced forward to the maximum extent. When the fall restriction claws 38 are in the forward position, the tips of the fall restriction claws 38 are positioned at a position where they further protrude radially inward of the chuck accommodating portion 15c. In this state, the fall restriction claws 38 abut against the outer peripheral edge of the wafer chuck 10, and the position of the wafer chuck 10 can be corrected to the specified centering position.

[0045] The fall-preventing claws 38 include a support surface 39 (see FIG. 1) that can support the underside of the outer peripheral edge of the wafer chuck 10 (flange wall 10f) when the upper part of the wafer chuck 10 is positioned within the chuck accommodating portion 15c, and a restricting wall 40 (see FIG. 1) that stands upward from the end of the support surface 39 that is away from the axial center position o of the wafer chuck 10. The support surface 39 is a flat surface that faces upward and is formed horizontally. The surface of the restricting wall 40 that faces the outer peripheral edge of the wafer chuck 10 when the upper part of the wafer chuck 10 is positioned within the chuck accommodating portion 15c serves as a centering surface 40c (see FIG. 1). When the fall-preventing claws 38 are in the advanced position, the centering surface 40c abuts against the outer peripheral edge of the wafer chuck 10, thereby centering the wafer chuck 10 with respect to the card mounting portion 21 of the ceiling wall 15. The centering surface 40c of the fall-regulating claw 38 is configured as an inclined surface that slopes downward toward the axis of the wafer chuck 10. The inclination of the centering surface 40c may be a flat surface or a conical tapered surface.

[0046] As shown in Fig. 4, the three-position control device 37 includes a cylinder device 41, a fluid control unit 42, and a displacement restriction device 43. The cylinder device 41 has a piston 44 that operates in conjunction with the forward and backward movement of the fall restriction claw 38, which is the object to be controlled. The piston 44 is displaceable to a retracted position, an intermediate position, and an advanced position by receiving thrust from air, which is the working fluid. The three positions of the piston 44, i.e., the retracted position, the intermediate position, and the advanced position, correspond to the forward and backward positions of the fall restriction claw 38 described above. The fluid control unit 42 controls the supply and exhaust of air to and from the cylinder device 41. The displacement restriction device 43 mechanically restricts the displacement of the piston 44 from the retracted position toward the advanced position to the intermediate position.

[0047] The cylinder device 41 includes a cylinder body 45 in which a piston 44 is housed so as to be able to move back and forth, and a piston rod 46 that is connected to the piston 44 and penetrates an end wall on one axial end of the cylinder body 45 and protrudes to the outside. The cylinder body 45 is fixedly installed on the outer lower surface 15b of the ceiling wall 15 in parallel with the fall-restricting claw 38. The cylinder body 45 is fixed to the outer lower surface 15b of the ceiling wall 15 so that the direction of advancement and retreat of the piston 44 is parallel to the direction of advancement and retreat of the fall-restricting claw 38. With regard to the cylinder device 41, the side from which the piston rod 46 protrudes relative to the cylinder body 45 is referred to as the "front," and the opposite side is referred to as the "rear." The front and rear of the cylinder device 41 coincide with the front and rear of the fall-restricting claw 38.

[0048] The cylinder body 45 is formed in the shape of a sealed cylindrical container. The interior of the cylinder body 45 is separated by the piston 44 into a first air chamber 47 (first fluid chamber) and a second air chamber 48 (second fluid chamber). The first air chamber 47 is a chamber located in front of the piston 44, and when air, which is a working fluid, is introduced into the first air chamber 47, the pressure of the introduced air presses the piston 44 in the backward direction. The second air chamber 48 is a chamber located behind the piston 44, and when air, which is a working fluid, is introduced into the second air chamber 48, the pressure of the introduced air presses the piston 44 in the forward direction.

[0049] As shown in FIG. 5 , the cylinder body 45 is formed with a first port 49 communicating with the first air chamber 47 and a second port 50 communicating with the second air chamber 48. The first port 49 is connected to a first inlet / outlet passage 51 (inlet / outlet piping) of a fluid control circuit constituting the fluid control unit 42. The second port 50 is connected to a second inlet / outlet passage 52 (inlet / outlet piping) of the fluid control circuit. When the piston 44 moves backward, air at a predetermined pressure is introduced into the first air chamber 47 through the first inlet / outlet passage 51, and air in the second air chamber 48 is discharged to the outside through the second inlet / outlet passage 52. When the piston 44 moves forward, air at a first operating pressure (described later) or a second operating pressure higher than the first operating pressure is introduced into the second air chamber 48 through the second inlet / outlet passage 52, and air in the first air chamber 47 is discharged to the outside through the first inlet / outlet passage 51. The pressure of the air introduced into the second air chamber 48 when the piston 44 moves forward (the first operating pressure and the second operating pressure) is switched depending on the operating position of the piston 44. The specific configuration of the fluid control circuit (fluid control unit 42) will be described in detail later.

[0050] As shown in Figure 4, the displacement restriction device 43 includes a base block 53 fixed to the outer lower surface 15b of the ceiling wall 15, an actuation rod 54 supported by the base block 53 so as to be able to move back and forth, and a spring member 55 that biases the actuation rod 54 toward one end in the axial direction. The base block 53 slidably supports the actuation rod 54 via a thrust bearing (not shown). The actuation rod 54 penetrates the base block 53 in the front-to-rear direction. The base block 53 is fixed to the outer lower surface 15b of the ceiling wall 15 so that the axis L1 of the actuation rod 54 is parallel to the axis L2 of the piston rod 46 of the cylinder device 41.

[0051] The fall restriction claws 38, the cylinder device 41, and the displacement restriction device 43 are arranged in parallel to one another. If the direction perpendicular to the forward / backward movement direction of the fall restriction claws 38 and the vertical direction is referred to as the "width direction" in the three-position control device 37, then the fall restriction claws 38, the cylinder device 41, and the displacement restriction device 43 are arranged in this order in the width direction. In other words, the fall restriction claws 38 are arranged on one side of the cylinder device 41 in the width direction, and the displacement restriction device 43 is arranged on the other side of the cylinder device 41 in the width direction.

[0052] Hereinafter, the side of the displacement restriction device 43 that is the same as the front side of the fall restriction claw 38 and the piston 44 will be referred to as the "front", and the side that is the same as the rear side of the fall restriction claw 38 and the piston 44 will be referred to as the "rear". The operating rod 54 of the displacement restriction device 43 is provided with a slip-out prevention flange 56 at its front end and a load-receiving flange 57 at its rear end. The slip-out prevention flange 56 is disposed on the front side of the base block 53, and the load-receiving flange 57 is disposed on the rear side of the base block 53. The outer diameters of the slip-out prevention flange 56 and the load-receiving flange 57 are larger than the outer diameter of the middle part of the operating rod 54. The slip-out prevention flange 56 abuts against the front end face of the base block 53, thereby preventing the operating rod 54 from slipping out rearward. A spring member 55 (coil spring) serving as a biasing means is disposed on the outer periphery of the rear region of the operating rod 54. The front end of the spring member 55 abuts against a spring receiving portion 53a recessed in the rear end face of the base block 53, and the other end abuts against the front side of the load-receiving flange 57. In this embodiment, the spring member 55 is a compression spring.

[0053] The load-receiving flange 57 is biased rearward by the spring member 55. The spring member 55 is disposed between the spring receiving portion 53a and the load-receiving flange 57 in a state in which it is pre-compressed by a predetermined amount. As a result, when the fall-off prevention flange 56 on the front end side of the operating rod 54 abuts against the front end surface of the base block 53, a preload is applied to the spring member 55 from the spring receiving portion 53a and the load-receiving flange 57. This preload serves as an initial load that causes the spring member 55 to start compressive deformation (spring deformation) when an external force directed forward is applied to the rear end surface 57r of the load-receiving flange 57. Therefore, a predetermined initial load is applied to the spring member 55 when it is set in the displacement prevention device 43. This initial load will be described in detail later. The rear end surface 57r of the load-receiving flange 57 serves as a load-receiving portion that receives the load of the piston 44 moving toward the forward position when the piston 44 of the cylinder device 41 is displaced from the retracted position to the intermediate position. The load-receiving flange 57 may be biased by an air cylinder instead of the spring member 55.

[0054] A load transmission arm 58 is connected to the front end of the piston rod 46 of the cylinder device 41, and is capable of transmitting the load acting on the piston rod 46 from the piston 44 to a rear end surface 57r of a load-receiving flange 57. The rear end surface 57r of the load-receiving flange 57, which is the load-receiving portion, is disposed in a position where a front surface 59a of a pressing claw 59 (described later) of the load transmission arm 58 abuts against the rear side when the piston 44 is displaced from the retracted position to the intermediate position (see FIG. 7).

[0055] The load transmission arm 58 is connected to the front end of the piston rod 46 that protrudes forward of the cylinder body 45. The load transmission arm 58 is composed of a base rod 60 that extends linearly below the outer lower surface 15b in a direction perpendicular to the extension direction of the piston rod 46, and an L-shaped rod 61 that is connected to the end of the base rod 60 and has a substantially L-shape in a front view. The end of the base rod 60 opposite the connection part with the L-shaped rod 61 is connected to the side of the fall-restricting claw 38. Therefore, the piston 44 of the cylinder device 41 and the fall-restricting claw 38 are connected to be able to move together via the piston rod 46 and the base rod 60. Although the cylinder device 41 has been described as an example of a cylinder having a piston rod 46, a rodless cylinder may also be used. In that case, the load transmission arm 58 may be connected to a member that moves in conjunction with the piston of the rodless cylinder.

[0056] The L-shaped rod 61 has a rear offset portion 62 extending rearward from the connection portion with the base rod 60, and a pressing claw 59 bending and extending from the rear end of the rear offset portion 62 toward a side away from the fall-restriction claw 38. The L-shaped rod 61 is disposed in a position where it does not overlap with the cylinder body 45 of the cylinder device 41 in the front-rear direction. The rear offset portion 62 of the L-shaped rod 61 has an extension length set so that the pressing claw 59 can be displaced rearward beyond the front end surface of the cylinder body 45 when the piston 44 of the cylinder device 41 is displaced rearward from the forward position. A front surface 59a of the pressing claw 59 is disposed so as to be able to abut from the rear side against a rear end surface 57r of the load-receiving flange 57, which is the load-receiving surface of the displacement-restriction device 43. The pressing claw 59 abuts against the rear end surface 57r of the load-receiving flange 57 when the piston 44 of the cylinder device 41 is displaced rearward from the forward position (see FIG. 7). At this time, the rear end surface 57r, which is the load receiving portion, receives the load of the piston 44 moving toward the forward position. In this embodiment, the rear offset portion 62 is provided in a part of the load transmission arm 58, which makes it possible to shorten the length in the front-rear direction from the front end of the displacement restriction device 43 to the rear end of the cylinder device 41. Therefore, each fall restriction mechanism 24 can be installed compactly in the limited installation space around the chuck accommodation portion 15c.

[0057] In FIG. 4, reference numeral 17 denotes a position detection sensor for detecting whether the fall-restricting claw 38 is positioned at the intermediate position. For example, a laser-type position detection sensor having a light-emitting element and a light-receiving element can be used as this position detection sensor 17. Position information detected by the position detection sensor 17 is output to a control device (not shown) that controls each part of the device. The cylinder device 41 is also provided with a position sensor (not shown) that detects when the piston 44 in the cylinder body 45 has reached the forward position, and a position sensor (not shown) that detects when the piston 44 has reached the retracted position. Whether the fall-restricting claw 38 is in the forward position or the retracted position is detected based on information from these two position sensors. This detection information is output to a control device (not shown).

[0058] 5, 8, and 12 are circuit diagrams of the fluid control unit 42. Fig. 5 shows the circuit state when the fall-restricting claw 38 is controlled to the retracted position, and Fig. 8 shows the circuit state when the fall-restricting claw 38 is controlled from the retracted position to the intermediate position. Also, Fig. 12 shows the circuit state when the fall-restricting claw 38 is controlled from the intermediate position to the advanced position. As shown in these figures, the fluid control unit 42 is equipped with a first pressure source 63 and a second pressure source 64 which have different air pressures (working pressures), a pressure switching valve 65 which can selectively switch the air supply from these pressure sources 63, 64, and a flow path switching valve 66 which can selectively switch the connection of the supply flow path and discharge flow path of air (working fluid) to the first air chamber 47 and the second air chamber 48 of the cylinder device 41.

[0059] The first pressure source 63 is capable of supplying a predetermined air pressure (hereinafter referred to as "first working pressure") such as 0.1 MPa, while the second pressure source 64 is capable of supplying an air pressure (hereinafter referred to as "second working pressure") that is higher than the first working pressure, such as 0.6 MPa.

[0060] The pressure switching valve 65 is disposed in the flow path upstream (on the pressure source side) of the flow path switching valve 66. The pressure switching valve 65 and the flow path switching valve 66 are connected by a relay passage 67. The pressure switching valve 65 is switchable between a first position (see FIGS. 5 and 12) where an introduction passage 68 communicating with the high-pressure second pressure source 64 is connected to the relay passage 67, and a second position (see FIG. 8) where an introduction passage 69 communicating with the low-pressure first pressure source 63 is connected to the relay passage 67. The pressure switching valve 65 is configured, for example, by a solenoid valve that can be switched between two positions. The solenoid of the pressure switching valve 65 is controlled by a control device (not shown).

[0061] In addition to the relay passage 67, the flow path switching valve 66 is connected to a first inlet / outlet passage 51 communicating with the first air chamber 47 of the cylinder device 41, a second inlet / outlet passage 52 communicating with the second air chamber 48 of the cylinder device 41, and a discharge passage 70 for discharging air to the outside. The flow path switching valve 66 is switchable between a first position (see FIG. 5) in which the relay passage 67 is connected to the first inlet / outlet passage 51 (first air chamber 47) and the second inlet / outlet passage 52 (second air chamber 48) is connected to the discharge passage 70, and a second position (see FIGS. 8 and 12) in which the relay passage 67 is connected to the second inlet / outlet passage 52 (second air chamber 48) and the first inlet / outlet passage 51 (first air chamber 47) is connected to the discharge passage 70. The flow path switching valve 66 is configured, for example, by a solenoid valve that can be switched between two positions. The solenoid of the flow path switching valve 66 is controlled by a control device (not shown).

[0062] The fluid control unit 42 is capable of selectively switching the flow path through which air (working fluid) flows to any of the following first, second, and third flow paths by controlling the pressure switching valve 65 and the flow path switching valve 66 in combination. <First flow path> A flow path that introduces air at a high second operating pressure into the first air chamber 47 and discharges air from the second air chamber 48. This first flow path is obtained by combining the operating states of the pressure switching valve 65 and the flow path switching valve 66 shown in Figure 5. <Second flow path> A flow path that introduces air at a low first operating pressure into the second air chamber 48 and discharges air from the first air chamber 47. This second flow path is obtained by combining the operating states of the pressure switching valve 65 and the flow path switching valve 66 shown in Figure 8. <Third flow path> A flow path that introduces air at a high second operating pressure into the second air chamber 48 and discharges air from the first air chamber 47. This third flow path is obtained by combining the operating states of the pressure switching valve 65 and the flow path switching valve 66 shown in Figure 12. In this embodiment, the pressure of the air introduced into the first air chamber 47 in the first flow path is the same as the pressure of the air introduced into the second air chamber 48 in the third flow path (second operating pressure). However, for example, by adding a pressure source with a different operating pressure and setting the switching position of the pressure switching valve 65 to position three, the pressure of the air introduced into the first air chamber 47 in the first flow path can be made different from the second operating pressure.

[0063] Here, the initial load of the spring member 55 of the displacement regulation device 43 described above is set to be greater than the thrust of the piston 44 when air of the first working pressure (low pressure) is introduced into the second air chamber 48 of the cylinder device 41, and smaller than the thrust of the piston 44 when air of the second working pressure (high pressure) is introduced into the second air chamber 48. The working load of the spring member 55 (the load until the piston moves to the forward position) is set to be smaller than the thrust of the piston 44 when air of the second working pressure (high pressure) is introduced into the second air chamber 48. In other words, the biasing force of the spring member 55, which is a biasing means, is set to be smaller than the thrust of the piston 44 when air of the second working pressure (high pressure) is introduced into the second air chamber 48.

[0064] The operating rod 54 of the displacement restriction device 43, which is biased in the backward direction by the spring member 55, is maintained in a stopped state at the intermediate position until the forward thrust of the piston 44, which is input through the load transmission arm 58, exceeds the initial load of the spring member 55. At this time, the piston 44 and the fall restriction pawl 38 are maintained at the intermediate position together with the operating rod 54. On the other hand, when the forward thrust of the piston 44, which is input through the load transmission arm 58, becomes greater than the initial load of the spring member 55, the operating rod 54 is displaced from the intermediate position toward the forward position. At this time, the piston 44 and the fall restriction pawl 38 are displaced from the intermediate position toward the forward position together with the operating rod 54. In addition, when the load-receiving flange 57 is biased by an air cylinder instead of the spring member 55, the thrust of the air cylinder at its initial position can be set to be greater than the thrust of the piston 44 when air at the first operating pressure (low pressure) is introduced into the second air chamber 48 of the cylinder device 41, and smaller than the thrust of the piston 44 when air at the second operating pressure (high pressure) is introduced into the second air chamber 48.

[0065] Next, the inspection operation using the prober 11 of this embodiment will be described. 6, 9, and 10 are partial cross-sectional front views of the wafer inspection device 1 similar to FIG. 1. Fig. 6 shows a state in which the wafer chuck 10 is fixed by suction to the underside of the ceiling wall 15 of the measurement section 16, Fig. 9 shows a state in which the fall-restricting claws 38 restrict the fall of the wafer chuck 10, and Fig. 10 shows a state in which the fall-restricting claws 38 center the wafer chuck 10. Fig. 7 is a view corresponding to Fig. 4 when the fall-restricting claws 38 are in the intermediate position, and Fig. 11 is a view corresponding to Fig. 4 when the fall-restricting claws 38 are in the advanced position. In the initial state, as shown in FIG. 1, the wafer chuck 10 is held by a chuck holder on the upper part of the alignment device 20, and the wafer W is placed on the placement surface 10b of the wafer chuck 10.

[0066] The alignment device 20 is moved by a moving device (not shown) to the measuring unit 16 where the inspection is performed. In this state, the chuck holder on the top of the alignment device 20 is maintained in a lowered state. In this state, an alignment operation is performed. Specifically, the X-axis moving stage 30 is moved so that the probe position detection camera 33 shown in Fig. 2 is positioned below the probe of the probe card 18. After this, the camera moving mechanism 34 moves the probe position detection camera 33 in the Z-axis direction to adjust the focus, and the probe position detection camera 33 detects the tip position of the probe on the probe card 18. The position of the probe tip in the horizontal plane (position in the X and Y directions) is detected by the camera coordinates, and the vertical position (position in the Z direction) is detected based on the focal position of the camera. Note that the probe card 18 is usually provided with several hundred to several thousand or more probes. For this reason, the probe position detection camera 33 does not detect the tip positions of all the probes, but usually only detects specific probes.

[0067] Next, the X-axis moving stage 30 is moved so that the wafer W held by the wafer chuck 10 is positioned below the alignment camera 35. In this state, the position of the electrodes of each chip on the wafer W is detected by the alignment camera 35. At this time, it is not necessary to detect the positions of all the electrodes on one chip, but it is sufficient to detect the positions of some of the electrodes. Also, it is not necessary to detect the electrodes of all the chips on the wafer W, but it is sufficient to detect the electrodes of some of the chips.

[0068] Next, based on the arrangement of the probes on the probe card 18 detected as described above and the arrangement of the electrodes on the wafer W, the Z-axis moving / rotating unit 32 adjusts the rotational position so that the arrangement direction of the probes coincides with the arrangement direction of the electrodes on the wafer W. Thereafter, the X-axis actuator 31 and the Y-axis actuator 29 adjust the positions of the wafer chuck 10 in the X and Y directions so that the electrodes of the chip to be inspected on the wafer W are positioned below the corresponding probes on the probe card 18. Thereafter, the Z-axis moving / rotating unit 32 raises the wafer chuck 10 in the Z-axis direction. At this time, the fall restriction claws 38 of the four fall restriction mechanisms 24 arranged on the underside of the ceiling wall 15 of the measuring section 16 are positioned in the retracted position as shown in FIGS.

[0069] The Z-axis moving / rotating unit 32 stops raising the wafer chuck 10 when the electrodes of the chip on the wafer W reach a height at which they come into contact with the probes of the probe card 18. At this time, the ring-shaped sealing member 23 on the upper part of the wafer chuck 10 comes into contact with the lower surface (chuck suction surface 15a) of the ceiling wall 15 around the periphery of the probe card 18, as shown in FIG. 6, and a sealed internal space S is formed between the lower surface of the ceiling wall 15 and the wafer chuck 10.

[0070] After this, the internal space S is evacuated by operating a suction device (not shown). This reduces the pressure in the internal space, and the wafer chuck 10 is pulled toward the underside of the probe card 18. As a result, each probe of the probe card 18 comes into contact with the corresponding electrode on the wafer W with a uniform force.

[0071] When the wafer chuck 10 holding the wafer W is fixed by suction to the ceiling wall 15 of the measurement unit 16, the alignment device 20 lowers the chuck holding portion in the Z-axis direction by operating the Z-axis moving / rotating unit 32. As a result, the chuck holding portion of the alignment device 20 moves away from the wafer chuck 10.

[0072] Thereafter, under the control of the fluid control units 42 of the four fall restriction mechanisms 24, each fall restriction claw 38 is advanced to the intermediate position as shown in FIGS. 6 and 7. At this time, each fluid control unit 42 is switched from the state shown in FIG. 5 (first flow path state) to the state shown in FIG. 8 (second flow path state). As a result, low-pressure air (first fluid pressure) is introduced into the second air chamber 48 of the cylinder device 41, and the air in the first air chamber 47 is discharged to the outside. At this time, when the piston 44 of the cylinder device 41 is displaced to the intermediate position by the thrust of the low-pressure air, the load transmission arm 58 connected to the piston rod 46 abuts against the rear end surface 57r (load receiving portion) of the load receiving flange 57 of the displacement restriction device 43 as shown in FIG. 7. As a result, the piston 44 and the fall restriction claw 38 stop at the intermediate position.

[0073] At this time, an initial load of the spring member 55 acts on the load-receiving flange 57, but this initial load is set to be larger than the thrust of the piston 44 when air at the first operating pressure (low pressure) is introduced into the second air chamber 48. Therefore, even if the load transmission arm 58 receives the thrust of the piston 44 and abuts against the rear end surface 57r of the load-receiving flange 57, the operating rod 54 does not displace forward. Therefore, the fall-restricting pawl 38 is maintained in the specified intermediate position. In this state, the tips of all four fall-regulating claws 38 protrude a predetermined amount into the inside of the chuck accommodating portion 15c, and the flat support surface 39 of each fall-regulating claw 38 is positioned below the flange wall 10f of the wafer chuck 10. As a result, even if the wafer chuck 10 moves away from the lower surface of the ceiling wall 15 due to the power being turned off, for example, the wafer chuck 10 can be received by the support surface 39 of the fall-regulating claws 38.

[0074] Once preparation for testing in measurement unit 16 is completed in this manner, test head 12 supplies a power supply current and a test signal to each chip on wafer W. Test head 12 receives a detection signal output from each chip on wafer W, and determines whether each chip is operating normally based on the detection signal. After the inspection, the wafer W waits with the wafer chuck 10 still attached to the ceiling wall 15 until the alignment device 20 returns from the other measurement unit 16.

[0075] When the alignment device 20 returns to the position below the wafer chuck 10 , the alignment device 20 raises the chuck holder by the Z-axis moving / rotating unit 32 and engages the chuck holder with the wafer chuck 10 . Thereafter, the fall restriction claws 38 of the four fall restriction mechanisms 24 are displaced to the retracted position as shown in Fig. 4 under the control of the fluid control unit 42. At this time, the fluid control unit 42 switches the flow path as shown in Fig. 5, and air at the second operating pressure (high pressure) is introduced into the first air chamber 47 of the cylinder device 41, while the air in the second air chamber 48 is discharged to the outside.

[0076] Next, the reduced pressure in the internal space S between the wafer chuck 10 and the ceiling wall 15, which is sealed by the ring-shaped seal member 23, is released, and the wafer chuck 10 is separated from the lower surface of the ceiling wall 15. As a result, the wafer chuck 10 is transferred to the chuck holding portion of the alignment device 20.

[0077] Thereafter, the alignment device 20 operates the Z-axis moving / rotating unit 32 to lower the inspected wafer W together with the wafer chuck 10. The alignment device 20 then moves to a predetermined transfer position and unloads the inspected wafer W.

[0078] On the other hand, when the wafer chuck 10 is held on the lower surface of the ceiling wall 15 by vacuum suction, a situation may occur in which the wafer chuck 10 separates from the lower surface of the ceiling wall 15 due to, for example, the power supply to the suction device being turned off. At this time, the fall restriction claws 38 of each fall restriction mechanism 24 are maintained in the intermediate position, so the wafer chuck 10 is received by the plurality of fall restriction claws 38, as shown in Fig. 9. However, when the decompression of the internal space S is released and the wafer chuck 10 separates from the lower surface of the ceiling wall 15, the wafer chuck 10 does not necessarily fall to a fixed position in a stable posture, and a situation may occur in which part of the outer periphery of the wafer chuck 10 falls to a position deviating from the support surface 39 of the fall restriction claws 38. In this case, a part of the outer peripheral edge of the wafer chuck 10 abuts against the inclined centering surfaces 40c of the drop-regulating claws 38 and is guided along the inclination of the centering surfaces 40c toward the support surfaces 39. As a result, the wafer chuck 10 is reliably supported in a stable position on the support surfaces 39 of the four drop-regulating claws 38.

[0079] When the wafer chuck 10 is transferred to the alignment device 20 together with the wafer W from a state in which the wafer chuck 10 is supported on the support surfaces 39 of the four drop-regulating claws 38 as described above, the drop-regulating claws 38 of the four drop-regulating mechanisms 24 are first displaced to their forward positions as shown in FIGS. 10 and 11 to center the wafer chuck 10 relative to the chuck accommodating portion 15c. At this time, the fluid control unit 42 is switched to the flow path state (third flow path state) shown in FIG. 12, and air at the second operating pressure (high pressure) is introduced into the second air chamber 48 of the cylinder device 41, while the air in the first air chamber 47 is discharged to the outside. In this case, the load transmission arm 58 connected to the piston rod 46 has already abutted against the rear end surface 57r of the load-receiving flange 57 of the displacement regulation device 43, but the thrust of the piston 44 acting on the load-receiving flange 57 through the load transmission arm 58 increases.

[0080] Here, the initial load of the spring member 55 acting on the operating rod 54 of the displacement regulation device 43 is set to be smaller than the thrust of the piston 44 when air at the second operating pressure (high pressure) is introduced into the second air chamber 48. Therefore, when air at the second operating pressure is introduced into the second air chamber 48 at this time and a thrust in the forward direction acts on the piston 44, the load transmission arm 58 overcomes the load of the spring member 55 of the displacement regulation device 43 and is displaced to the forward position. As a result, each fall regulation claw 38 is displaced to the forward position as shown in Figures 10 and 11.

[0081] In this manner, when each fall-regulating claw 38 is displaced to the forward position, the support surface 39 of each fall-regulating claw 38 comes into sliding contact with the underside of the flange wall 10f of the wafer chuck 10, while the centering surface 40c presses the outer peripheral edge of the flange wall 10f of the wafer chuck 10 toward the center of the chuck accommodating portion 15c. As a result, the wafer chuck 10 is centered so as to coincide with the specified centering position, and the relative position of the wafer chuck 10 with respect to the chuck holding portion of the alignment device 20 below is also corrected.

[0082] 7 and 9, the fall restriction claws 38 of the four fall restriction mechanisms 24 are then retracted to the intermediate position, and in this state, the chuck holder of the alignment device 20 is raised to engage the chuck holder with the wafer chuck 10. Thereafter, the fall restriction claws 38 of the four fall restriction mechanisms 24 are displaced to the retracted position, and the chuck holder of the alignment device 20 is lowered. The alignment device 20 then moves to a predetermined transfer position and unloads the inspected wafer W.

[0083] As described above, the prober 11 of this embodiment includes a fall prevention mechanism 24 for preventing the wafer chuck 10 from falling, a plurality of fall prevention claws 38 that are provided on the underside of the measuring unit 16 so as to be movable forward and backward and that prevent the wafer chuck 10 from falling from the underside of the measuring unit 16 in an advanced state, and a three-position control device 37 that controls the advance and retreat positions of the plurality of fall prevention claws 38. The three-position control device 37 can switch the positions of the plurality of fall prevention claws 38 between a retreated position that allows the wafer chuck 10 to pass between the fall prevention claws 38, an intermediate position that receives the wafer chuck 10 that has moved away from the underside of the measuring unit 16, and an advanced position that centers the wafer chuck 10. Therefore, even if the wafer chuck 10 that is attracted to the measuring unit 16 moves away from the measuring unit 16 due to, for example, being turned off, the fall of the wafer chuck 10 can be prevented by the fall prevention claws 38 by displacing the fall prevention claws 38 to the intermediate position under the control of the three-position control device 37. Furthermore, from this state, by displacing the plurality of fall-control claws 38 to the forward position under the control of the three-position control device 37, the wafer chuck 10 can be centered by the plurality of fall-control claws 38, and the positional deviation between the wafer chuck 10 and the alignment device 20 below it can be corrected. Therefore, when the prober 11 of this embodiment is adopted, even after the wafer chuck 10 moves away from the underside of the measurement section 16 and is temporarily held by the fall prevention mechanism 24, the wafer chuck 10 can be handed over to the alignment device 20 in the appropriate position.

[0084] Furthermore, in the prober 11 of this embodiment, the outer peripheral edge of the wafer chuck 10 is formed in a circular shape concentric with the wafer W held on its upper surface, and each of the fall prevention claws 38 of the fall prevention mechanism 24 moves forward and backward along the radial direction of the wafer chuck 10. This allows each of the fall prevention claws 38 to move forward and backward in the shortest distance without loss relative to the lower surface of the wafer chuck 10, and also makes it possible to quickly center the wafer chuck 10 when centering the wafer chuck 10 using the plurality of fall prevention claws 38.

[0085] Furthermore, in the prober 11 of this embodiment, two or more (specifically, four) drop-preventing claws 38 are provided spaced apart in the outer circumferential direction of the wafer chuck 10. Therefore, by displacing the two or more drop-preventing claws 38 to the forward position, the wafer chuck 10 can be easily and accurately centered.

[0086] Furthermore, in the prober 11 of this embodiment, each drop restriction claw 38 has a horizontal support surface 39 capable of supporting the underside of the wafer chuck 10, and a restriction wall 40 standing from the end of the support surface 39 on the side away from the axial position o of the wafer chuck 10. The surface of the restriction wall 40 facing the outer periphery of the wafer chuck 10 serves as a centering surface 40c that abuts against the outer periphery of the wafer chuck 10 when the drop restriction claws 38 are in the advanced position. Therefore, while the wafer chuck 10 is placed on the support surface 39 of the drop restriction claws 38, the centering surface 40c of the drop restriction claws 38 can press the outer periphery of the wafer chuck 10 from the radially outward side, thereby centering the wafer chuck 10. Therefore, when this configuration is adopted, the wafer chuck 10 can be corrected to the appropriate position while maintaining a stable posture.

[0087] Furthermore, in the prober 11 of this embodiment, the centering surface 40c of the drop-restricting claws 38 is configured as an inclined surface that slopes downward toward the axis of the wafer chuck 10. Therefore, even if the wafer chuck 10 is significantly deviated from the appropriate position when the wafer chuck 10 moves away from the lower surface of the measurement unit 16 due to, for example, being turned off, the lowered wafer chuck 10 can be guided to the vicinity of the appropriate position by the inclined centering surface 40c. Therefore, when this configuration is adopted, the wafer chuck 10 can be reliably centered by the centering surface 40c when the drop-restricting claws 38 are displaced to the advanced position.

[0088] The present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the centering surface 40c of the fall-restricting claw 38 is configured as an inclined surface, but the centering surface 40c does not necessarily have to be an inclined surface. The centering surface 40c may be, for example, a surface that stands up vertically.

[0089] In the above embodiment, the position control device that controls the advance / retract position of the fall-restriction claw 38 is configured by the three-position control device 37. However, the position control device is not limited to the three-position control device 37. The position control device may have a function of being able to stop at four or more positions as long as it can stop at at least three positions, namely, the retreat position, the intermediate position, and the advance position.

[0090] In addition, in the above embodiment, the cylinder device 41 that operates the piston 44 by air pressure is employed, but the cylinder device 41 is not limited to this. The cylinder device 41 may be configured to operate the piston 44 by the pressure of other fluids such as special gases or liquids, for example. [Explanation of symbols]

[0091] 10...Wafer chuck 11...Prober 12...Test head 16…Measuring part 18...Probe card 20...Alignment device 24...Fall prevention mechanism 37...Three-position control device (position control device) 38...Fall prevention claw 39…support surface 40...Regulatory barriers 40c...Centering surface 57r...Rear end surface (load receiving part) W...wafer

Claims

1. a measurement unit having a probe card electrically connected to the test head; a wafer chuck that holds a wafer on an upper surface thereof, on which a plurality of chips are formed, and that is held on a lower surface of the measurement unit to bring electrodes of the chips into contact with corresponding probes of the probe card; an alignment device that detachably engages with the wafer chuck and aligns the wafer held by the wafer chuck with respect to the probe card; a fall prevention mechanism that prevents the wafer chuck from falling from the lower surface of the measurement unit, The fall prevention mechanism includes: a plurality of drop prevention claws provided on the underside of the measuring unit so as to be able to move forward and backward, and which, in an advanced state, prevent the wafer chuck from dropping from the underside of the measuring unit; a position control device that controls the advance / retract positions of the plurality of fall-prevention claws, The position control device is capable of switching the positions of the plurality of drop-control claws among a retracted position that allows the wafer chuck to pass between the drop-control claws, an intermediate position that receives the wafer chuck from below after it has moved away from the underside of the measuring unit, and an advanced position that centers the wafer chuck.

2. the outer peripheral edge of the wafer chuck is formed in a circular shape concentric with the wafer held on the upper surface of the wafer chuck; 2. The prober according to claim 1, wherein each of said drop-regulating claws moves forward and backward along the radial direction of said wafer chuck.

3. 3. The prober according to claim 2, wherein two or more of the drop-regulating claws are provided spaced apart from each other in the circumferential direction of the wafer chuck.

4. Each of the fall prevention claws is a horizontal support surface capable of supporting a lower surface of an outer peripheral edge portion of the wafer chuck; a restriction wall rising from an end of the support surface on a side away from an axial center position of the wafer chuck, 4. The prober according to claim 2, wherein a surface of the regulating wall facing the outer peripheral edge of the wafer chuck is a centering surface that abuts against the outer peripheral edge when the fall-regulating claw is in the advanced position.

5. 5. The prober according to claim 4, wherein the centering surface is configured as an inclined surface that slopes downward toward the axis of the wafer chuck.

Images