Three-position control device and three-position control method

Abstract

To provide a three-position control device and a three-position control method capable of rapidly and accurately displacing a control object to an intermediate position, and capable of stably maintaining the displaced control object in a stop condition at an intermediate position.SOLUTION: A three-position control device includes a cylinder device, a fluid controller, and a displacement regulating device. The cylinder device displaces a piston to each of a retreating position, an intermediate position, and an advancing position. The cylinder device includes a first fluid chamber for retreating, and a second fluid chamber for advancing. The fluid controller switches the advancing and retreating position of the piston. A second working pressure at displacing from the intermediate position to the advancing position is set to be larger than a first working pressure at displacing from the retreating position to the intermediate position. The displacement regulating device includes a load receiver and energizing means. Energizing force of the energizing means is set to be larger than thrust by the first working pressure and smaller than thrust by the second working pressure.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a three-position control device and a three-position control method for stopping a controlled object at three positions: a backward position, an intermediate position, and a forward position. [Background technology]

[0002] BACKGROUND ART A three-position control device that uses an air cylinder is known as a three-position control device that stops a controlled object at three positions (see, for example, Patent Document 1).

[0003] The three-position control device described in Patent Document 1 has a piston slidably housed within the cylinder body of an air cylinder, and the interior of the cylinder body is separated into two air chambers by the piston. A piston rod that penetrates an end wall of the cylinder body is connected to the piston, and an object to be controlled can be connected to the piston rod. In addition, a magnetic sensor is provided in the cylinder body to detect the advance / retract position of the piston.

[0004] In this three-position control device, when the controlled object is to be displaced to the backward position, high-pressure air is introduced into one air chamber and the air in the other air chamber is discharged to the outside. Conversely, when the controlled object is to be displaced to the forward position, high-pressure air is introduced into the other air chamber and the air in one air chamber is discharged to the outside. When the controlled object is stopped at an intermediate position, high-pressure air is introduced into the two air chambers before and after the piston when the magnetic sensor detects that the piston has been displaced to the intermediate position. This causes the piston to be pressed by high-pressure air from both the front and rear, stopping the piston and the controlled object at the intermediate position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-2203 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the three-position control device described in Patent Document 1 fixes the position of the piston by introducing high-pressure air into the air chambers before and after the piston when a magnetic sensor detects that the piston has moved to the intermediate position. This means that a time lag is likely to occur between the time the piston moves to the intermediate position and the time the high-pressure air actually brakes the piston, making it difficult to accurately stop the piston at the intermediate position. Furthermore, when trying to accurately stop the piston at the intermediate position, it becomes difficult to quickly move the piston.

[0007] Furthermore, the three-position control device described in Patent Document 1 holds the piston in a middle position by balancing the air pressure acting on the front and rear of the piston. This makes it difficult to stably stop the piston and the controlled object in a middle position, and improvements in this regard are desired.

[0008] Therefore, the present invention aims to provide a three-position control device and a three-position control method that can quickly and accurately displace a controlled object to an intermediate position and can stably maintain the displaced controlled object in a stopped state at the intermediate position. [Means for solving the problem]

[0009] In order to solve the above problems, the three-position control device and the three-position control method according to the present invention employ the following configuration. That is, a three-position control device according to one aspect of the present invention includes a cylinder device having a piston that operates in conjunction with an object to be controlled, the piston being displaceable to a retracted position, an intermediate position, and an advanced position by receiving thrust of a hydraulic fluid; a fluid control unit that controls intake and discharge of hydraulic fluid to and from the cylinder device; and a displacement regulation device that regulates displacement of the piston from the retracted position toward the advanced position at the intermediate position, wherein the cylinder device has a first fluid chamber into which the hydraulic fluid is introduced so as to press the piston toward the retracted position, and a second fluid chamber into which the hydraulic fluid is introduced so as to press the piston toward the advanced position, and the fluid control unit controls a first fluid chamber that introduces the hydraulic fluid into the first fluid chamber at a predetermined working pressure and discharges the hydraulic fluid from the second fluid chamber. a first flow path that introduces the working fluid into the second fluid chamber at a first working pressure and discharges the working fluid from the first fluid chamber; and a third flow path that introduces the working fluid into the second fluid chamber at a second working pressure that is higher than the first working pressure and discharges the working fluid from the first fluid chamber. The displacement control device has a load receiving portion that receives a load of the piston toward the advanced position when the piston is displaced from the retracted position to the intermediate position, and a biasing means that biases the load receiving portion in a direction against the load input from the piston, and the biasing force of the biasing means is set to be greater than the thrust of the piston due to the first working pressure and smaller than the thrust of the piston due to the second working pressure.

[0010] When the three-position control device of this aspect displaces the controlled object to the retracted position, the fluid control section is switched to the first flow path. This introduces working fluid at a predetermined working pressure into the first fluid chamber and discharges working fluid from the second fluid chamber to the outside. As a result, the piston displaces to the retracted position together with the controlled object. Furthermore, when the controlled object is to be displaced from the retracted position to the intermediate position, the fluid control section is switched to the second flow path. This introduces working fluid at the first working pressure into the second fluid chamber, and the working fluid in the first fluid chamber is discharged to the outside. As a result, the piston displaces to the intermediate position together with the controlled object. At this time, when the piston displaces to the intermediate position, the piston directly or indirectly abuts against the load receiving portion of the displacement control device, thereby receiving the load in the displacement direction. At this time, the load receiving portion is biased by the biasing means in a direction against the load input from the piston, and the biasing force of the biasing means is set to be greater than the thrust of the piston due to the first operating pressure but smaller than the thrust of the piston due to the second operating pressure. Therefore, the piston, which moves forward due to the thrust of the first operating pressure, is restricted from further forward displacement while the load is received by the load receiving portion of the displacement restriction device. As a result, the piston and the controlled object are maintained in a stable stopped state at the intermediate position. When the controlled object is to be displaced from the intermediate position to the forward position, the fluid control section is switched to the third flow path. This introduces working fluid at the second working pressure into the second fluid chamber, and the working fluid in the first fluid chamber is discharged to the outside. As a result, the piston receives a thrust greater than the biasing force of the biasing means of the displacement restriction device, and is displaced to the forward position together with the controlled object. In the three-position control device of this configuration, the piston can be displaced by appropriate operating pressures (first operating pressure and second operating pressure) depending on the presence or absence of a biasing force of the biasing means of the displacement control device, so that the controlled object can be quickly displaced to the desired stopping position.

[0011] The biasing means may be a spring member, and an initial load at which the spring member begins to deform may be set to be greater than the thrust of the piston due to the first operating pressure and smaller than the thrust of the piston due to the second operating pressure.

[0012] In this case, the biasing force at the start of biasing can be easily set and adjusted by adjusting the initial load of the spring member, and the structure of the biasing means can be simplified.

[0013] The predetermined operating pressure is preferably set to the same pressure as the first operating pressure or the second operating pressure.

[0014] In this case, the pressure sources that can be switched between in the fluid control section can be limited to only two different pressure sources, so if this configuration is adopted, the fluid system used can be simplified and the fluid control section can be made more compact.

[0015] The fluid control unit may include a flow path switching valve that can selectively switch the supply flow path and discharge flow path of the working fluid between the first fluid chamber and the second fluid chamber, and a pressure switching valve that can selectively switch the pressure source connected to the supply flow path between a first pressure source whose pressure is the first working pressure and a second pressure source whose pressure is the second working pressure.

[0016] In this case, by combining the flow path switching valve and the pressure switching valve, it is possible to easily obtain a fluid control section that can switch between the first, second, and third flow paths.

[0017] The cylinder device includes a cylinder body in which the piston is accommodated so as to be able to move back and forth freely, and a piston rod connected to the piston and protruding to the outside from the axial end of the cylinder body, and the displacement control device is installed outside the cylinder body so that the displacement direction of the load receiving part is parallel to the axial direction of the piston rod, and a load transmission arm capable of transmitting the load acting on the piston rod from the piston to the load receiving part may be connected to the piston rod.

[0018] In this case, when the piston receives thrust from the working fluid and moves back and forth, the displacement is transmitted via the piston rod to the load transmission arm outside the cylinder body. Therefore, even if the displacement control device is located at a distance outside the cylinder body, the movement of the piston can be transmitted to the load receiving portion of the displacement control device via the load transmission arm. Therefore, when this configuration is adopted, the spatial occupation form of the three-position control device can be flexibly changed depending on the installation location, etc.

[0019] Furthermore, a three-position control method according to one aspect of the present invention is a three-position control method using a cylinder device having a piston that is interlocked with an object to be controlled, the piston being displaceable to a retracted position, an intermediate position, and an advanced position by receiving thrust of a hydraulic fluid, and a displacement restriction device that restricts displacement of the piston from the retracted position toward the advanced position at the intermediate position, wherein the cylinder device is provided with a first fluid chamber into which the hydraulic fluid is introduced so as to press the piston toward the retracted position, and a second fluid chamber into which the hydraulic fluid is introduced so as to press the piston toward the advanced position, and the displacement restriction device is provided with a load receiving portion that receives a load of the piston toward the advanced position when the piston is displaced from the retracted position to the intermediate position, and biasing means that biases the load receiving portion in a direction against the load input of the piston, and the biasing force of the biasing means is The thrust force of the working fluid is set to be greater than the thrust force due to the working pressure of the working fluid when the piston is displaced from the retracted position to the intermediate position and smaller than the thrust force due to the working pressure of the working fluid when the piston is displaced from the intermediate position to the advanced position; when the piston is displaced to the retracted position, the working fluid is introduced into the first fluid chamber at a predetermined working pressure and the working fluid is discharged from the second fluid chamber; when the piston is displaced from the retracted position to the intermediate position and stopped at the intermediate position, the working fluid is introduced into the second fluid chamber at a first working pressure and the working fluid is discharged from the first fluid chamber; and when the piston is displaced from the intermediate position to the advanced position, the working fluid is introduced into the second fluid chamber at a second working pressure that is higher than the first working pressure and the working fluid is discharged from the first fluid chamber.

[0020] In this three-position control method, the load receiving portion is biased by the biasing means in a direction against the load input from the piston. The biasing force of the biasing means is set to be greater than the thrust of the piston due to the first operating pressure when displacing the piston from the retracted position to the intermediate position, and smaller than the thrust of the piston due to the second operating pressure when moving the piston from the intermediate position to the advanced position. Therefore, when the piston is advanced by the thrust of the first operating pressure when displacing from the retracted position to the intermediate position, the load of the piston is received by the load receiving portion of the displacement restriction device, and further forward displacement of the piston is restricted. As a result, the piston and the controlled object are stably maintained in a stopped state at the intermediate position. Furthermore, in the three-position control method of this aspect, the pressure of the working fluid introduced into the second fluid chamber is changed when the piston is displaced from the retracted position to the intermediate position and when the piston is displaced from the intermediate position to the advanced position, which makes it possible to quickly displace the piston from the intermediate position to the advanced position without being significantly affected by factors such as the difference in pressure-receiving surfaces at the front and rear of the piston. [Effects of the Invention]

[0021] The three-position control device and three-position control method of the present invention can quickly and accurately displace a controlled object to an intermediate position, and can maintain the displaced controlled object in a stable stopped state at the intermediate position. [Brief explanation of the drawings]

[0022] [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

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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 .

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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."

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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).

[0042] 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.

[0043] The drop-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 facing upward and is formed approximately 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 drop-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 top 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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).

[0053] 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.

[0054] 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.

[0055] 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).

[0056] 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.

[0057] 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.

[0058] 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).

[0059] 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).

[0060] 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.

[0061] 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.

[0062] 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 begins to displace from the intermediate position toward the forward position. At this time, the piston 44 and the fall restriction pawl 38 begin to displace 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] On the other hand, when the wafer chuck 10 is attached to 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] As described above, the three-position control device 37 of this embodiment includes the cylinder device 41, the fluid control unit 42, and the displacement restriction device 43. The cylinder device 41 is provided with a first air chamber 47 (first fluid chamber) into which air is introduced so as to press the piston 44 toward the retracted position, and a second air chamber 48 (second fluid chamber) into which air is introduced so as to press the piston 44 toward the advanced position. The fluid control unit 42 is switchable between a first flow path that introduces air at a predetermined pressure into the first air chamber 47 and discharges air from the second air chamber 48, a second flow path that introduces air at a first operating pressure (low pressure) into the second air chamber 48 and discharges air from the first air chamber 47, and a third flow path that introduces air at a second operating pressure (high pressure) into the second air chamber 48 and discharges air from the first air chamber 47. The displacement restriction device 43 includes a load receiving portion (rear end surface 57r of the load receiving flange 57) that receives a load in the forward direction of the piston 44 when the piston 44 is displaced from the retracted position side to the intermediate position, and a spring member 55 that biases the load receiving portion in a direction against the load input from the piston 44. The biasing force of the spring member 55 is set to be greater than the thrust in the forward direction of the piston 44 due to the first operating pressure and smaller than the thrust in the forward direction of the piston 44 due to the second operating pressure.

[0082] Therefore, by appropriately switching the flow path of air supplied to and discharged from the first air chamber 47 and the second air chamber 48 of the cylinder device 41 using the fluid control unit 42, the piston 44, which is linked to the controlled object, can be stopped accurately at three positions: the retracted position, the intermediate position, and the advanced position. In particular, when the piston 44 is displaced from the retracted position to the intermediate position, air at the first operating pressure is introduced into the second air chamber 48, and the piston 44 is displaced to the intermediate position. Then, the load transmission arm 58, which is linked to the piston 44, abuts against the load receiving portion (rear end surface 57r of the load receiving flange 57) of the displacement regulation device 43, and the piston 44 is stopped accurately at the intermediate position. In other words, the position of the piston 44 can be accurately maintained at the intermediate position by the balance between the initial load of the spring member 55 of the displacement regulation device 43 and the thrust of the air acting on the piston 44. Therefore, when the three-position control device 37 of this embodiment is adopted, the controlled object can be displaced to an intermediate position quickly and accurately, and the displaced controlled object can be stably maintained in a stopped state at the intermediate position.

[0083] Furthermore, in the three-position control device 37 of this embodiment, the air actuation pressure when displacing the piston 44 from the intermediate position to the retracted position is set to the same pressure as the air actuation pressure (second actuation pressure) when displacing the piston 44 from the intermediate position to the advanced position. This allows the fluid control unit 42 to switch between only two pressure sources with different pressures (the low-pressure first pressure source 63 and the high-pressure pressure source 64). Therefore, when this configuration is adopted, the air supply and discharge system used can be simplified, and the fluid control unit 42 can be made more compact. The air actuation pressure when the piston 44 is displaced from the intermediate position to the retracted position may be set to the same pressure as the air actuation pressure (first actuation pressure) when the piston 44 is displaced from the retracted position to the intermediate position, in which case the same effect can be obtained.

[0084] Furthermore, in the three-position control device 37 of this embodiment, the fluid control unit 42 is provided with a flow path switching valve 66 that can selectively switch the connection of the supply flow path and the discharge flow path between the first air chamber 47 and the second air chamber 48, and a pressure switching valve 65 that can selectively switch the pressure source connected to the air supply flow path between the first pressure source 63 and the second pressure source 64. Therefore, when this configuration is adopted, a fluid control unit 42 that can switch between the first, second, and third flow paths can be easily obtained by combining the flow path switching valve 66 and the pressure switching valve 65.

[0085] Furthermore, in the three-position control device 37 of this embodiment, the displacement regulation device 43 is installed outside the cylinder body 45 so that the displacement direction (axial direction of the operating rod 54) of the load receiving portion (rear end surface 57r of the load receiving flange 57) is parallel to the axial direction of the piston rod 46. A load transmission arm 58 capable of transmitting the load acting on the piston rod 46 from the piston 44 to the load receiving portion (rear end surface 57r of the load receiving flange 57) is connected to the piston rod 46. Therefore, even when the displacement regulation device 43 is installed at a separate position outside the cylinder body 45 (a position separated in the width direction), the behavior of the piston 44 can be transmitted to the load receiving portion of the displacement regulation device 43 via the load transmission arm 58. Therefore, when this configuration is adopted, it becomes possible to flexibly change the spatial occupation form of the three-position control device 37 according to the installation position, etc. Specifically, for example, as shown in Fig. 3, the fall-controlling claw 38 (control object), the cylinder device 41, and the displacement-controlling device 43 can be arranged almost side by side, and these can be compactly arranged in the four corners of the ceiling wall 15.

[0086] Furthermore, in the three-position control method of the present embodiment described above, the initial load of the spring member 55 of the displacement regulation device 43 is set to be greater than the thrust caused by the first working pressure when displacing the piston 44 from the retracted position to the intermediate position and less than the thrust caused by the second working pressure when moving the piston 44 from the intermediate position to the advanced position. When actually displacing the piston 44 from the retracted position to the intermediate position and stopping it at the intermediate position, air at the first working pressure is introduced into the second air chamber 48 and air is discharged from the first air chamber 47. When displacing the piston 44 from the intermediate position to the advanced position, air at a second working pressure higher than the first working pressure is introduced into the second air chamber 48 and air is discharged from the first air chamber 47. As a result, the balance between the initial load of the spring member 55 of the displacement regulation device 43 and the thrust of the air acting on the piston 44 allows the piston 44 to be accurately maintained at the intermediate position. Therefore, when the three-position control method of this embodiment is adopted, the controlled object can be displaced to an intermediate position quickly and accurately, and the displaced controlled object can be maintained in a stable stopped state at the intermediate position. Furthermore, in the three-position control method of this embodiment, the pressure of the air introduced into the second air chamber 48 is different when the piston 44 is displaced from the retracted position to the intermediate position and when the piston 44 is displaced from the intermediate position to the advanced position. This makes it possible to quickly displace the piston 44 from the intermediate position to the advanced position without being significantly affected by factors such as the difference in pressure-receiving surfaces at the front and rear of the piston 44.

[0087] 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 object of position control by the three-position control device 37 is the fall-prevention claw 38 of the wafer inspection device 1, but the object of position control by the three-position control device 37 is not limited to this. The object of position control may be another part of the wafer inspection device 1. Furthermore, the three-position control device 37 can be applied to various devices other than the wafer inspection device 1.

[0088] 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]

[0089] 37...Three-position control device 41...Cylinder device 42...Fluid control section 43...Displacement control device 44...Piston 45...Cylinder body 46...Piston rod 47...First air chamber (first fluid chamber) 48...Second air chamber (second fluid chamber) 55...spring member (urging means) 57r…Rear end surface 58...Load transfer arm 63...First pressure source 64...Second pressure source 65...Pressure switching valve 66...Flow path switching valve

Claims

1. a cylinder device having a piston that moves in conjunction with a controlled object, the piston being displaceable to a retreated position, an intermediate position, and an advanced position by receiving thrust from a working fluid; a fluid control unit that controls the intake and exhaust of the working fluid to and from the cylinder device; a displacement restriction device that restricts displacement of the piston from the retracted position toward the advanced position at the intermediate position, The cylinder device a first fluid chamber into which the working fluid is introduced so as to press the piston toward the retracted position; a second fluid chamber into which the hydraulic fluid is introduced so as to urge the piston toward the forward position, the fluid control section is switchable among a first flow path that introduces the working fluid into the first fluid chamber at a predetermined working pressure and discharges the working fluid from the second fluid chamber, a second flow path that introduces the working fluid into the second fluid chamber at a first working pressure and discharges the working fluid from the first fluid chamber, and a third flow path that introduces the working fluid into the second fluid chamber at a second working pressure that is higher than the first working pressure and discharges the working fluid from the first fluid chamber, the displacement restriction device includes a load receiving portion that receives a load of the piston toward the advanced position when the piston is displaced from the retracted position to the intermediate position, and biasing means that biases the load receiving portion in a direction against the load input from the piston, A three-position control device in which the biasing force of the biasing means is set to be greater than the thrust of the piston due to the first operating pressure and smaller than the thrust of the piston due to the second operating pressure.

2. the biasing means is a spring member, 2. The three-position control device according to claim 1, wherein an initial load at which the spring member begins to deform is set to be greater than the thrust of the piston due to the first operating pressure and smaller than the thrust of the piston due to the second operating pressure.

3. 3. The three-position control device according to claim 1, wherein the predetermined operating pressure is set to be the same as the first operating pressure or the second operating pressure.

4. The fluid control unit includes: a flow path switching valve that can selectively switch the connection of a supply flow path and a discharge flow path of the working fluid to the first fluid chamber and the second fluid chamber; 4. The three-position control device according to claim 3, further comprising a pressure switching valve that can selectively switch a pressure source connected to the supply flow path between a first pressure source whose pressure is the first operating pressure and a second pressure source whose pressure is the second operating pressure.

5. The cylinder device a cylinder body in which the piston is accommodated so as to be able to move forward and backward; a piston rod connected to the piston and protruding from an axial end of the cylinder body to the outside, the displacement restriction device is installed outside the cylinder body so that the displacement direction of the load receiving portion is parallel to the axial direction of the piston rod, 3. A three-position control device according to claim 1, wherein a load transmission arm is connected to the piston rod, and is capable of transmitting a load acting on the piston rod from the piston to the load receiving portion.

6. a cylinder device having a piston that moves in conjunction with a controlled object, the piston being displaceable to a retreated position, an intermediate position, and an advanced position by receiving thrust from a working fluid; a displacement restriction device that restricts displacement of the piston from the retracted position toward the advanced position at the intermediate position, the cylinder device is provided with a first fluid chamber into which the working fluid is introduced so as to press the piston toward the retracted position, and a second fluid chamber into which the working fluid is introduced so as to press the piston toward the advanced position, the displacement restriction device is provided with a load receiving portion that receives a load of the piston directed toward the forward position when the piston is displaced from the retracted position side to the intermediate position, and a biasing means that biases the load receiving portion in a direction against the load input of the piston, the biasing force of the biasing means is set to be greater than the thrust force due to the working pressure of the working fluid when the piston is displaced from the retracted position to the intermediate position, and smaller than the thrust force due to the working pressure of the working fluid when the piston is displaced from the intermediate position to the advanced position, When the piston is displaced to the retracted position, the working fluid is introduced into the first fluid chamber at a predetermined working pressure, and the working fluid is discharged from the second fluid chamber; When the piston is displaced from the retracted position to the intermediate position and stopped at the intermediate position, the working fluid is introduced into the second fluid chamber at a first working pressure and the working fluid is discharged from the first fluid chamber; A three-position control method in which, when the piston is displaced from the intermediate position to the forward position, the working fluid is introduced into the second fluid chamber at a second working pressure higher than the first working pressure, and the working fluid is discharged from the first fluid chamber.

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