JP2019106447A - Prober and probe inspection method - Google Patents

Abstract

To provide a prober and a probe inspection method which can determine whether an appropriate amount of overdrive can be secured and can realize good contact between a probe and an electrode pad on a wafer.SOLUTION: After a wafer chuck 34 is raised by a Z-axis movement/rotation unit 72 to form an internal space S between the wafer chuck 34 and the probe card 32, the height position of a wafer chuck 34 is detected by a distance sensor 38 for each step while the internal space S is stepped down by a vacuum electro-pneumatic regulator 54. Then, an overdrive amount calculation unit 115 calculates the overdrive amount from the detection result of the distance sensor 38.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a prober and a probe inspection method for inspecting electrical characteristics of a plurality of semiconductor devices (chips) formed on a semiconductor wafer, in particular, a multi-stage type prober and a probe inspection including a plurality of measurement units. On the way.

  The semiconductor manufacturing process has a large number of processes, and various inspections are performed in various manufacturing processes to improve quality assurance and yield. For example, when a plurality of chips of the semiconductor device are formed on the semiconductor wafer, the electrode pads of the semiconductor device of each chip are connected to the test head, the power and the test signal are supplied from the test head, and the semiconductor device outputs Wafer level inspections are performed in which signals are measured by a test head to electrically inspect whether they operate properly.

  After wafer level inspection, the wafer is attached to the frame and diced into individual chips with a dicer. For each chip that has been cut, only chips that have been confirmed to operate properly are packaged in the next assembly process, and malfunctioning chips are removed from the assembly process. In addition, the packaged final product is subjected to shipping inspection.

  Wafer level inspection is performed using a prober that brings probes into contact with the electrode pads of each chip on the wafer. Is the probe electrically connected to the terminal of the test head, and the test head supplies power and test signals to each chip through the probe, and does the test head detect the output signal from each chip and operate normally? Measure

  In the semiconductor manufacturing process, in order to reduce the manufacturing cost, the enlargement of the wafer and the further miniaturization (integration) are being promoted, and the number of chips formed on one wafer becomes very large. ing. Along with this, the time required for inspection of one wafer with a prober is also long, and improvement in throughput is required. Therefore, in order to improve the throughput, multi-probing is performed in which a large number of probes are provided so that a plurality of chips can be inspected simultaneously. In recent years, the number of chips to be simultaneously inspected has been increasing and attempts have been made to simultaneously inspect all the chips on a wafer. Therefore, the tolerance of the alignment which contacts an electrode pad and a probe is small, and it is calculated | required that a position accuracy of the movement in a prober is raised.

  On the other hand, although it is conceivable to increase the number of probers as the simplest way to increase the throughput, when the number of probers is increased, there arises a problem that the installation area of the prober in the manufacturing line also increases. In addition, if the number of probers is increased, the cost of the apparatus will be increased accordingly. Therefore, it is required to suppress the increase of the installation area and the increase of the device cost to increase the throughput.

  Under such a background, for example, Patent Document 1 proposes a multi-stage type prober provided with a plurality of measurement units. In this prober, an alignment device that performs relative alignment between the wafer and the probe card is configured to be able to move mutually between the measurement units. As a result, the alignment device can be shared by the measurement units, and space saving and cost reduction can be achieved.

  Further, in the prober described in Patent Document 1, a vacuum suction method for holding the wafer chuck on the probe card side is adopted. In this vacuum suction method, the internal space (sealed space) formed between the wafer chuck and the probe card is depressurized by the pressure reducing means to draw the wafer chuck toward the probe card side, so that each probe card has a wafer. A contact operation is performed to bring the electrode pads of each chip into contact.

JP, 2016-032110, A

  By the way, in the prober described in Patent Document 1, when bringing the electrode pads of the chips of the wafer into contact with the probes of the probe card by the pressure reduction of the internal space, it is grasped whether or not the appropriate overdrive amount can be secured. It is difficult. If an appropriate amount of overdrive can not be secured, the contact pressure necessary to electrically conduct between the probe and the electrode pad can not be secured, and accurate inspection can not be performed.

  The present invention has been made in view of such circumstances, and it is possible to grasp whether or not an appropriate amount of overdrive can be secured, and to realize a good contact between an electrode pad on a wafer and a probe. Prober and probe inspection method that can

  In order to achieve the above object, the following invention is provided.

  A prober according to a first aspect of the present invention includes a wafer chuck for holding a wafer, a probe card provided so as to face the wafer chuck and having a probe at a position corresponding to each electrode pad of the wafer, a wafer chuck and a probe An internal space is formed by an annular seal member forming an internal space between the card and a mechanical elevating means for removably supporting the wafer chuck and moving the wafer chuck up and down toward the probe card, and the seal member In the state, the pressure reduction unit performs step pressure reduction by dividing pressure reduction of the internal space into multiple steps in stages and height that detects the height position of the wafer chuck for each step when step pressure reduction is performed On the basis of the detection results of the position detection means and the height position detection means, the contact between the probe and the electrode pad Comprising the overdrive amount calculating means for calculating the over drive amount.

  In the prober according to the second aspect of the present invention, in the first aspect, the overdrive amount calculation means is a wafer chuck when a change occurs in the height position of the wafer chuck per step when the step pressure reduction is performed. The height position is determined as the contact position at which the probe and the electrode pad have begun to contact, and the overdrive amount is calculated with the contact position as a reference position.

  In the prober according to the third aspect of the present invention, in the first aspect or the second aspect, the height position detection means is a non-contact distance sensor disposed at a position separated from the wafer chuck.

  In the probe inspection method according to the fourth aspect of the present invention, in a state in which the internal space is formed between the wafer chuck and the probe card, the pressure reduction of the internal space is divided into a plurality of steps and stepwise The probe card and the wafer of the probe card based on the detection results of the pressure reduction step to be performed, the height position detection step of detecting the height position of the wafer chuck at each step when step pressure reduction is being performed, And an overdrive amount calculating step of calculating an overdrive amount when the electrode pad on the wafer held by the chuck comes in contact with the wafer.

  The probe inspection method according to a fifth aspect of the present invention is the probe inspection method according to the fourth aspect, wherein the overdrive amount calculating step changes the height position of the wafer chuck per step when step pressure reduction is performed. The height position of the wafer chuck is determined as the contact position at which the probe and the electrode pad have begun to contact, and the overdrive amount is calculated with the contact position as a reference position.

  In the probe inspection method according to the sixth aspect of the present invention, in the fourth aspect or the fifth aspect, the height position detection step uses the non-contact distance sensor disposed at a position separated from the wafer chuck. Detect the height position of the chuck.

  According to the present invention, it can be grasped whether or not the appropriate amount of overdrive can be secured, and a good contact can be realized between the electrode pad on the wafer and the probe.

An external view showing an entire configuration of a prober of the present embodiment A plan view showing the overall configuration of the prober of the present embodiment Schematic diagram showing the configuration of the measurement unit in the prober of the present embodiment Schematic diagram showing the configuration of the measurement unit in the measurement unit shown in FIG. 3 Functional block diagram showing the configuration of the control device of the prober of this embodiment Flow chart showing the contact operation in the prober of the present embodiment Diagram for explaining the contact operation in the prober of the present embodiment The figure which showed an example of the relationship between the internal pressure of internal space at the time of contact operation in the prober of this embodiment being performed, and the height position of a wafer chuck.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings.

  FIG.1 and FIG.2 is the external view and top view which showed the whole structure of the prober 10 of this embodiment.

  As shown in FIGS. 1 and 2, the prober 10 of the present embodiment includes a loader unit 14 that supplies and recovers a wafer W to be inspected (see FIG. 4), and a measurement unit 12 disposed adjacent to the loader unit 14. And have. Measurement unit 12 has a plurality of measurement units 16. When wafer W is supplied from loader unit 14 to each measurement unit 16, each measurement unit 16 inspects the electric characteristics of each chip of wafer W. (Wafer level inspection) is performed. Then, the wafer W inspected by each measurement unit 16 is recovered by the loader unit 14. The prober 10 also includes an operation panel 22, a control device 60 (see FIG. 5) described later, and the like.

  The loader unit 14 has a load port 18 on which the wafer cassette 20 is mounted, and a transfer unit 24 for transferring the wafer W between the measurement units 16 of the measurement unit 12 and the wafer cassette 20. The transport unit 24 includes a transport unit drive mechanism (not shown), and is configured to be movable in the X and Z directions, and is configured to be rotatable in the θ direction (around the Z direction). Further, the transport unit 24 includes a transport arm 26 which is configured to be telescopically movable back and forth by the transport unit drive mechanism. A suction pad (not shown) is provided on the upper surface portion of the transfer arm 26. The transfer arm 26 holds the wafer W by vacuum suction of the back surface of the wafer W by the suction pad. Thus, the wafer W in the wafer cassette 20 is taken out by the transfer arm 26 of the transfer unit 24 and transferred to the measurement units 16 of the measurement unit 12 while being held on the upper surface thereof. Further, the inspected wafer W after the inspection is returned from each measuring unit 16 to the wafer cassette 20 in the reverse path.

  FIG. 3 is a schematic view showing the configuration of the measurement unit 12 in the prober 10 of the present embodiment. FIG. 4 is a schematic view showing the configuration of the measurement unit 16 in the measurement unit 12 shown in FIG.

  As shown in FIG. 3, the measurement unit 12 has a stacked structure (multistage structure) in which a plurality of measurement units 16 are stacked in a multistage manner, and each measurement unit 16 is arranged along the X direction and the Z direction. It is arranged in dimension. In the present embodiment, as an example, four measurement units 16 are stacked in three stages in the Z direction in the X direction.

  The measurement unit 12 includes a housing (not shown) having a grid shape in which a plurality of frames are combined in a grid shape. This housing is formed by combining a plurality of frames extending in the X direction, the Y direction, and the Z direction in a lattice, and the components of the measuring unit 16 are respectively formed in the space portions formed by these frames. Is placed.

  Each of the measurement units 16 has the same configuration, and as shown in FIG. 4, includes the head stage 30, the probe card 32, and the wafer chuck 34. In addition, each measuring unit 16 is provided with a test head (not shown). The test head is supported above the head stage 30 by a test head holder not shown.

  The head stage 30 is supported by a frame member (not shown) which constitutes a part of the housing, and the probe card 32 is detachably mounted and fixed. The probe card 32 mounted and fixed to the head stage 30 is provided to face the wafer holding surface 34 a of the wafer chuck 34. The probe card 32 is replaced in accordance with the wafer W (device) to be inspected.

  The probe card 32 is provided with a plurality of probes 36 such as cantilevers and spring pins which are arranged corresponding to the positions of the electrode pads of the respective chips of the wafer W to be inspected. Each probe 36 is electrically connected to a terminal of a test head (not shown), and power and test signals are supplied from the test head to each chip through each probe 36, and an output signal from each chip is detected by the test head To determine if it works properly. The connection configuration between the probe card 32 and the test head is not an essential part of the present invention, and thus detailed description will be omitted.

  The probe 36 has spring characteristics, and contacts the electrode pad with a predetermined contact pressure by raising the contact point from the tip position of the probe 36. In addition, when the probe 36 is in contact with the electrode pad in an overdrive state when performing an electrical inspection, the tip of the probe 36 is embedded in the surface of the electrode pad and a needle mark is formed on the surface of the electrode pad. It is supposed to Note that the overdrive is a probe that ensures that the electrode pad and the probe 36 contact with each other in consideration of the inclination of the wafer W and the array surface of the tip of the probe 36, and the variation of the tip position of the probe 36, etc. This is a state in which the surface of the electrode pad, that is, the surface of the wafer W is raised by a distance α to a position higher than the tip position of 36. In addition, the movement amount to further raise the surface of the wafer W from the tip position (contact position) of the probe 36, that is, the distance α is referred to as an overdrive amount.

  The wafer chuck 34 sucks and fixes the wafer W by vacuum suction. The wafer chuck 34 has a wafer holding surface 34a on which the wafer W to be inspected is placed, and a plurality of suction ports 40 are provided on the wafer holding surface 34a (only one is shown in FIG. 4). The suction port 40 is connected to a suction device (vacuum source) 44 such as a vacuum pump via a suction passage 42 formed inside the wafer chuck 34. A wafer suction electromagnetic valve 46 is provided in a suction path connecting the suction device 44 and the suction path 42. The wafer suction electromagnetic valve 46 is controlled by the wafer suction electromagnetic valve control unit 110 (see FIG. 5).

  An elastic ring-shaped seal member (chuck seal rubber) 48 formed to surround the wafer W held on the wafer holding surface 34 a is provided outside the wafer holding surface 34 a of the wafer chuck 34. When the wafer chuck 34 is moved (lifted) toward the probe card 32 by the Z-axis movement / rotation unit 72 described later, the ring-shaped seal member 48 contacts the lower surface of the head stage 30. An internal space S (see FIG. 7) surrounded by the probe card 32 and the ring-shaped seal member 48 is formed. The ring-shaped seal member 48 is an example of the annular seal member of the present invention.

  The head stage 30 is provided with a suction port 50 for reducing the pressure in the internal space S formed between the probe card 32 and the wafer chuck 34. The suction port 50 is connected to the suction device 44 via a suction passage 52 formed inside the head stage 30. A vacuum electropneumatic regulator 54 is provided in a suction path connecting the suction device 44 and the suction path 52. The vacuum electro-pneumatic regulator 54 is a control valve that adjusts the internal pressure (vacuum degree) of the internal space S. The vacuum electro-pneumatic regulator 54 is controlled by a suction control unit 114 (see FIG. 5) described later. The vacuum electro-pneumatic regulator 54 is an example of the pressure reducing means of the present invention.

  A heating / cooling source is provided inside the wafer chuck 34 so that the wafer W to be inspected can be inspected for electrical characteristics at high temperature (for example, at most 150 ° C.) or low temperature (for example at least -40 ° C.) A heating and cooling mechanism (not shown) is provided. As a heating and cooling mechanism, a known appropriate heater / cooler can be adopted, for example, a double layer structure of a heating layer of a surface heater and a cooling layer provided with a passage of a cooling fluid, or heat Various things are considered, such as a heating / cooling device having a single layer structure in which a cooling pipe having a heater wound around the conductor is embedded. Also, instead of electrical heating, a thermal fluid may be circulated, or a Peltier element may be used.

  The wafer chuck 34 is detachably supported by an alignment device 70 described later. The alignment device 70 performs relative alignment between the wafer W held by the wafer chuck 34 and the probe card 32 by moving the wafer chuck 34 in the X, Y, Z, and θ directions.

  The alignment device 70 detachably supports the wafer chuck 34, moves the wafer chuck 34 in the Z-axis direction, and rotates in the θ direction about the Z axis while rotating in the θ direction, and the Z axis movement An X-axis moving base 74 supporting the rotating unit 72 and moving in the X-axis direction, and a Y-axis moving base 76 supporting the X-axis moving base 74 and moving in the Y-axis direction.

  Each of the Z-axis movement / rotation unit 72, the X-axis movement base 74, and the Y-axis movement base 76 is configured to move or rotate the wafer chuck 34 in a predetermined direction by a mechanical drive mechanism including at least a motor. Ru. As a mechanical drive mechanism, it is comprised by the ball screw drive mechanism which combined the servomotor and the ball screw, for example. Further, the present invention is not limited to the ball screw drive mechanism, and may be configured by a linear motor drive mechanism, a belt drive mechanism, or the like. The Z-axis movement / rotation unit 72, the X-axis movement base 74, and the Y-axis movement base 76 are configured such that the movement distance, movement direction, movement speed, and acceleration of the wafer chuck 34 can be changed by control units described later. ing. Specifically, the present embodiment has the following configuration.

  The Z-axis movement / rotation unit 72 is an example of the mechanical elevating means of the present invention, and a Z-axis drive motor 122 (for example, a stepping motor, a servomotor, a linear motor, etc.) for moving the wafer chuck 34 in the Z-axis direction. 5) and a Z-axis encoder (for example, a rotary encoder, a linear scale, etc.) (not shown) for detecting the movement distance of the wafer chuck 34 in the Z-axis direction. The Z-axis drive motor 122 is controlled based on a motor control signal from a Z-axis movement control unit 106 (see FIG. 5) described later, and drives the wafer chuck 34 to move to the target position at a desired movement speed or acceleration. . Further, the Z-axis encoder outputs an encoder signal in accordance with the movement of the wafer chuck 34.

  The Z-axis movement / rotation unit 72 also includes a rotation drive motor 124 (for example, a stepping motor, a servomotor, a linear motor, etc.) (see FIG. 5) for rotating the wafer chuck 34 in the θ direction. The rotary encoder (for example, a rotary encoder etc.) (not shown) for detecting the rotation angle to (theta) direction is provided. The rotation drive motor 124 is controlled based on a motor control signal from a θ rotation control unit 108 (see FIG. 5) described later, and drives the wafer chuck 34 to move to the target position at a desired rotation speed or acceleration. In addition, the rotary encoder outputs an encoder signal according to the rotation of the wafer chuck 34.

  The X-axis moving table 74 is an X-axis drive motor 118 (for example, a stepping motor, a servomotor, a linear motor, etc.) (see FIG. 5) for moving the wafer chuck 34 in the X-axis direction. An X-axis encoder (for example, a rotary encoder, a linear scale, etc.) (not shown) for detecting the movement distance in the direction is provided. The X-axis drive motor 118 is controlled based on a motor control signal from an X-axis movement control unit 102 (see FIG. 5) described later, and drives the wafer chuck 34 to move to the target position at a desired movement speed or acceleration. . In addition, the X-axis encoder outputs an encoder signal according to the movement of the wafer chuck 34.

  The Y-axis moving table 76 is a Y-axis drive motor 120 (for example, a stepping motor, a servomotor, a linear motor, etc.) (see FIG. 5) for moving the wafer chuck 34 in the Y-axis direction. A Y-axis encoder (for example, a rotary encoder, a linear scale, etc.) (not shown) for detecting the movement distance in the direction is provided. The Y-axis drive motor 120 is controlled based on a motor control signal from a Y-axis movement control unit 104 (see FIG. 5) described later, and drives the wafer chuck 34 to move to the target position at a desired movement speed or acceleration. . In addition, the Y-axis encoder outputs an encoder signal according to the movement of the wafer chuck 34.

  The alignment device 70 is provided for each stage (see FIG. 3), and is configured to be mutually movable between the plurality of measurement units 16 arranged in each stage by an alignment device drive mechanism (not shown). . That is, the alignment apparatus 70 is shared among a plurality of (four in this example) measurement units 16 arranged in the same stage, and mutually moves between the plurality of measurement units 16 arranged in the same stage. Do. The alignment device 70 moved to each measurement unit 16 is fixed while being positioned at a predetermined position by a positioning and fixing device (not shown), and the wafer chuck 34 is moved in the X, Y, Z, θ directions and held by the wafer chuck 34 The relative alignment between the wafer W and the probe card 32 is performed. Although not shown, the alignment device 70 detects the relative positional relationship between the electrode pads of the respective chips of the wafer W held by the wafer chuck 34 and the probes 36, and And a wafer alignment camera. Further, the alignment device drive mechanism is constituted by a mechanical drive mechanism such as a ball screw drive mechanism, a linear motor drive mechanism, and a belt drive mechanism.

  A ring-shaped seal member (Z-axis seal rubber) 78 having elasticity and annularly formed along the outer periphery is provided on the wafer chuck support surface 72a of the Z-axis movement / rotation unit 72 that constitutes the upper surface of the alignment device 70. In addition, a suction port 80 is provided inside the ring-shaped seal member 78 of the wafer chuck support surface 72a. The suction port 80 is connected to the suction device 44 via a suction passage 82 formed inside the wafer chuck 34. In the suction path connecting the suction device 44 and the suction path 82, a chuck fixing electromagnetic valve 84 and a throttle valve 86 are provided in order from the suction device 44 side. The chuck fixing solenoid valve 84 is controlled by a chuck fixing solenoid valve control unit 112 (see FIG. 5) described later.

  A positioning pin 88 is provided on the outside of the ring-shaped seal member 78 of the wafer chuck support surface 72a of the Z-axis movement / rotation unit 72 so that the relative positional relationship of the wafer chuck 34 with the alignment device 70 is always constant. ing. The positioning pins 88 are provided at three locations at equal intervals along the circumferential direction centering on the central axis of the wafer chuck 34 (only two are shown in FIG. 4). On the lower surface of the wafer chuck 34, a V block 90 which is a positioning member is provided at a position corresponding to each positioning pin 88. When the wafer chuck 34 is suctioned and fixed by vacuum suction, the corresponding positioning pins 88 are engaged in the V grooves of each V block 90 to move the wafer chuck 34 in the horizontal direction (X direction and Y direction). And the relative positioning between the alignment device 70 and the wafer chuck 34 is performed.

  In the present embodiment, the alignment apparatus 70 vacuum-chucks and fixes the wafer chuck 34. However, as long as the wafer chuck 34 can be fixed, the alignment unit 70 may be a fixing unit other than vacuum-chucking. It may be fixed.

  The prober 10 in the present embodiment further includes a distance sensor (length measuring sensor) 38 in addition to the above configuration. The distance sensor 38 is an example of the height position detection means of the present invention, and detects the height position (position in the Z direction) of the wafer chuck 34. If the height position of the wafer chuck 34 can be detected as the distance sensor 38, various sensors can be used regardless of contact type or non-contact type, but the height of the wafer chuck 34 to be measured can be used. A non-contact sensor that does not affect the position is desirable. As a noncontact sensor, a noncontact distance sensor (for example, a laser length measuring sensor or the like) using a laser or an ultrasonic wave is suitably used. The distance sensor 38 in the present embodiment is a non-contact distance sensor, and is attached to the sensor attachment portion of the Z-axis movement / rotation unit 72. The distance sensor 38 detects the height position (the position in the Z-axis direction) of the wafer chuck 34 by measuring the distance from the distance sensor 38 to the wafer chuck 34.

  The position where the distance sensor 38 is disposed is not particularly limited to this embodiment, and may be disposed, for example, on the head stage 30 side (for example, the head stage 30 or the probe card 32).

  FIG. 5 is a functional block diagram showing the configuration of the control device 60 of the prober 10 of the present embodiment.

  The control device 60 stores data necessary for the operation and processing of each part of the prober 10, and the like. The control device 60 is realized by, for example, a general-purpose computer such as a personal computer or a microcomputer.

  The control device 60 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), an input / output interface, and the like. In the control device 60, various programs such as control programs stored in the ROM are expanded in the RAM, and the programs expanded in the RAM are executed by the CPU, whereby each of the units in the control device 60 shown in FIG. A function is realized, and various arithmetic processing and control processing are executed via the input / output interface.

  As shown in FIG. 5, the control unit 60 includes an overall control unit 100, an X-axis movement control unit 102, a Y-axis movement control unit 104, a Z-axis movement control unit 106, a θ rotation control unit 108, and a wafer suction electromagnetic valve control. And a chuck fixing electromagnetic valve control unit 112, a suction control unit 114, and the like.

  The overall control unit 100 centrally controls the units that constitute the prober 10. Specifically, the overall control unit 100 controls an operation (contact operation) for bringing the electrode pads of the respective chips of the wafer W to be inspected into contact with the respective probes 36 of the probe card 32. Further, in addition to the contact operation, the overall control unit 100 performs movement control for mutually moving the alignment apparatus 70 between the measurement units 16 and control of the wafer level inspection operation by the test head. The control other than the contact operation is not a characteristic part of the present invention, and thus the detailed description is omitted.

  The X-axis movement control unit 102 controls the drive of the X-axis drive motor 118 provided on the X-axis movement base 74 to move the wafer chuck 34 in the X-axis direction by moving the X-axis movement base 74 in the X-axis direction. Move to The Y-axis movement control unit 104 controls the driving of the Y-axis drive motor 120 provided on the Y-axis movement base 76 to move the Y-axis movement base 76 in the Y-axis direction, thereby the wafer chuck 34 is in the Y-axis direction. Move to The Z-axis movement control unit 106 moves the wafer chuck 34 in the Z-axis direction by raising and lowering the Z-axis movement / rotation unit 72 by controlling the drive of the Z-axis drive motor 122 provided in the Z-axis movement / rotation unit 72. Move to The θ rotation control unit 108 controls the driving of the rotation drive motor 124 provided in the Z axis movement / rotation unit 72 to rotate the Z axis movement / rotation unit 72 in the θ direction, thereby the wafer chuck 34 in the θ direction. Rotate to.

  The wafer suction electromagnetic valve control unit 110 adjusts the suction pressure by the suction port 40 by controlling ON / OFF (open / close) of the wafer suction electromagnetic valve 46 to fix the wafer W to the wafer chuck 34 / Selectively switch non-fixed.

  The chuck fixing electromagnetic valve control unit 112 adjusts the suction pressure by the suction port 80 by controlling ON / OFF (open / close) of the chuck fixing electromagnetic valve 84, and the wafer for the Z axis movement / rotation unit 72 The fixation / non-fixation of the chuck 34 is selectively switched.

  The suction control unit 114 controls the operation of the vacuum electro-pneumatic regulator 54 to steplessly adjust the internal pressure (degree of vacuum) of the internal space S.

  Furthermore, the overall control unit 100 in the present embodiment includes an overdrive amount calculation unit 115. The overdrive amount calculation unit 115 functions as an overdrive amount calculation means of the present invention, and calculates the overdrive amount when each probe 36 of the probe card 32 contacts the electrode pad of each chip of the wafer W. Do.

  Further, a distance sensor 38 is connected to the overall control unit 100. The distance sensor 38 detects the height position (the position in the Z direction) of the wafer chuck 34 as described above. The detection result of the distance sensor 38 is stored in a storage device (not shown) of the control device 60. The storage device is configured of, for example, a readable and writable storage device such as a RAM or an HDD.

  The overdrive amount calculation unit 115 acquires the detection result of the distance sensor 38 from the storage device described above. Then, the overdrive amount calculation unit 115 calculates the overdrive amount based on the detection result of the distance sensor 38. The method of calculating the overdrive amount will be described later.

  Next, the contact operation (an example of the probe inspection method) in the prober 10 of the present embodiment will be described with reference to FIGS. This operation is performed under the control of the overall control unit 100.

  FIG. 6 is a flowchart showing the contact operation in the prober 10 of the present embodiment. FIG. 7 is a view for explaining the contact operation in the prober 10 of the present embodiment. FIG. 8 is a view showing an example of the relationship between the internal pressure (negative pressure) in the internal space S and the height position of the wafer chuck 34 when the contact operation in the prober 10 of the present embodiment is performed.

(Pre-operation)
The preliminary operation of the contact operation will be described.

  First, the wafer chuck 34 is delivered to the alignment apparatus 70 in a state in which the alignment device 70 is moved to the measurement unit 16 to be inspected from now on as a preliminary operation of the contact operation and then positioned and fixed by a positioning fixing device not shown. . The delivery operation of the wafer chuck 34 before the start of the contact operation is not an essential part of the present invention, and thus the detailed description is omitted.

  After the wafer chuck 34 is delivered to the alignment apparatus 70, the chuck fixing electromagnetic valve control unit 112 turns on the chuck fixing electromagnetic valve 84 (open state), and the wafer chuck support surface of the Z axis movement / rotation unit 72 The wafer chuck 34 is suctioned and fixed to 72a (see FIG. 4). At this time, relative positioning between the alignment device 70 and the wafer chuck 34 is performed by engaging the positioning pin 88 of the Z-axis moving / rotating unit 72 in the V groove of the V block 90 of the wafer chuck 34.

  Thereafter, when the wafer W is supplied (loaded) to the wafer chuck 34 supported and fixed to the alignment apparatus 70, the wafer suction electromagnetic valve control unit 110 turns on the wafer suction electromagnetic valve 46 (opened state). The wafer W is fixed by suction to the holding surface 34a (see FIG. 4).

(Step S10: alignment process)
Next, the X-axis movement control unit 102, the Y-axis movement control unit 104, and the θ rotation control unit 108 are controlled by the overall control unit 100 based on the result of imaging by the needle position detection camera and the wafer alignment camera. The X-axis drive motor 118, the Y-axis drive motor 120, and the rotation drive motor 124 are controlled to perform relative alignment between the wafer W held by the wafer chuck 34 and the probe card 32.

(Step S12: Z-axis raising process)
Next, as indicated by reference numerals 500A and 500B in FIG. 7, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to raise the Z-axis movement / rotation unit 72, thereby forming a ring-shaped seal member. The wafer chuck 34 is moved toward the probe card 32 to a height position where the contact 48 contacts the lower surface of the head stage 30. As a result, the ring-shaped seal member 48 contacts the lower surface of the head stage 30, and the internal space S formed between the wafer chuck 34 and the probe card 32 is sealed from the outside.

(Step S14: Decompression Process)
Next, as shown by reference numeral 500C in FIG. 7, the suction control unit 114 controls the operation of the vacuum electro-pneumatic regulator 54 to start the pressure reduction of the internal space S via the suction port 50 (time in FIG. 8). t ₀ ). At this time, the suction control unit 114 performs step pressure reduction in which pressure reduction of the internal space S is divided into a plurality of steps and stepwise. Specifically, the internal pressure of the internal space S changes from the initial pressure P ₀ to the set pressure P ₁ as shown in the graph in the upper part of FIG. 8 (graph showing temporal changes in internal pressure of the internal space) The internal pressure (negative pressure) of the internal space S is controlled to be gradually increased by a minute pressure ΔP every predetermined time Δt.

  In the depressurization step, the wafer chuck fixing release step is performed at the same time as or after the start of the depressurization step. In the wafer chuck fixing release step, the chuck fixing electromagnetic valve control unit 112 turns off the chuck fixing electromagnetic valve 84 (closed state), and the wafer chuck by the suction port 80 (see FIG. 4) of the Z axis movement / rotation unit 72. Unlock 34. As a result, when the pressure reduction step is performed, the wafer chuck 34 moves (rises) toward the probe card 32 in accordance with the internal pressure of the internal space S.

  Here, in the present embodiment, since the throttling valve 86 is provided in the suction path connecting between the suction path 82 of the Z-axis movement / rotation unit 72 and the chuck fixing electromagnetic valve 84, the start of the pressure reduction process Even if the wafer chuck fixing release process is performed at the same time as or after the above, the negative pressure on the lower side (the Z axis movement / rotation part 72 side) of the wafer chuck 34 is not suddenly lost There is. Therefore, when the wafer chuck 34 is pulled from both the upper and lower sides (that is, both sides of the Z-axis moving and rotating portion 72 and the probe card 32), restraint from the lower side suddenly (ie, Z-axis moving and rotating portion 72) Since the fixing force (due to adsorption from the surface) is not lost, it is possible to reduce abnormal vibration and abnormal contact accompanying rapid movement of the wafer chuck 34. Therefore, since the wafer chuck 34 can be prevented from being rapidly detached from the Z-axis moving / rotating portion 72 when the wafer chuck fixing release step is performed, the delivery operation of the wafer chuck 34 can be performed more stably. It becomes possible.

  In the present embodiment, as an example, the configuration in which the throttling valve 86 is provided in the suction path connecting the suction path 82 of the Z-axis movement / rotation unit 72 and the chuck fixing electromagnetic valve 84 is shown. The throttling valve 86 may be provided in a path connecting the suction port 80 of the axial movement / rotation unit 72 and the suction device 44, for example, the throttling valve 86 in the suction passage 82 of the Z axis movement / rotation unit 72. May be provided.

(Step S16: height position detection step)
The distance sensor 38 detects the height position of the wafer chuck 34 for each step when the step pressure reduction of the internal space S is performed. The detection result of the distance sensor 38 is output to and stored in a storage device (not shown) of the control device 60.

(Step S18: Judgment process)
Next, the suction control unit 114 determines whether the internal pressure of the inner space S has reached the set pressure P _1. In a case where the internal pressure of the inner space S does not reach the set pressure P ₁ (when No in step S18), and returns to step S14, repeating the step S14 and subsequent steps. On the other hand, when the internal pressure of the inner space S has reached the set pressure P ₁ (in the case of Yes in step S18), and proceeds to the next step S20.

  The internal pressure of the internal space S may be detected directly by, for example, a pressure sensor provided on the wafer chuck 34 or the head stage 30, or may be incorporated in or connected to the vacuum electro-pneumatic regulator 54. It may be detected by a pressure sensor.

(Step S20: Contact position detection step)
Next, the overdrive amount calculation unit 115 acquires the detection result of the distance sensor 38 from the storage device (not shown) of the control device 60. Then, the overdrive amount calculation unit 115 detects a contact position (reference position) at which the probe 36 and the electrode pad on the wafer W start to contact based on the detection result of the distance sensor 38. Specifically, the contact position is detected as follows.

  The graph shown in the lower part of FIG. 8 is a graph showing temporal changes in the height position of the wafer chuck 34 when the step pressure reduction in the internal space S (see the graph shown in the upper part of FIG. 8) is performed. As shown in this graph, when step pressure reduction of the internal space S is performed, the height position of the wafer chuck 34 changes by the micro height Δh each time the internal pressure of the internal space S changes by the micro pressure ΔP. . At this time, before and after the contact between the probe 36 and the electrode pad on the wafer W, the amount of change in the height position of the wafer chuck 34 per step (minute height Δh) differs. That is, after contact between the probe 36 and the electrode pad on the wafer W, the wafer chuck 34 receives a reaction force (a reaction force when the probe 36 is crushed) from each probe 36, so before they contact each other. Compared to this, the amount of change in the height position of the wafer chuck 34 per step becomes smaller.

  The overdrive amount calculation unit 115 utilizes the characteristic that the moving amount of the wafer chuck 34 per step changes before and after the probe 36 and the electrode pad on the wafer W contact when the internal space S is stepped down in steps. The contact position where the probe 36 and the electrode pad on the wafer W begin to contact is detected.

For example, in the example shown in FIG. 8, variation in the height position of the wafer chuck 34 per one step it is changed at time t _s. In this case, the overdrive amount calculation unit 115 detects the height position H ₀ of the wafer chuck 34 at time t _s as the contact position. If the reaction force of the ring-shaped seal member 48 is very small, the amount of change in the height position of the wafer chuck 34 per step may change immediately after the step pressure reduction of the internal space S is started. .

(Step S22: Overdrive Amount Calculation Step)
Next, the overdrive amount calculating unit 115, a height position H ₁ of the wafer chuck 34 when the internal pressure of the inner space S has reached the set pressure P _1, a contact position H detected by the above contact position detection step The difference with ₀ is calculated as the overdrive amount D.

  The overdrive amount calculation unit 115 outputs the calculated overdrive amount D to a monitor (not shown). Thus, the overdrive amount D is displayed on the monitor. Therefore, the operator can grasp the overdrive amount D by confirming the display on the monitor.

When the overdrive amount calculated by the overdrive amount calculation unit 115 is not appropriate under the control of the overall control unit 100, the suction control unit 114 sets the pressure so that the overdrive amount falls within the appropriate range. Control to change P ₁ may be performed. Also, change of the set pressure P ₁ may also be operator performs manual.

  As described above, when the wafer chuck 34 is delivered from the alignment device 70 (Z-axis movement / rotation unit 72) to the head stage 30 (the probe card 32 side), each probe 36 of the probe card 32 has a uniform contact pressure. At this time, the wafer W is in contact with the electrode pads of the chips, and the wafer level inspection can be started. Thereafter, power and test signals are supplied from the test head to the respective chips of the wafer W through the respective probes 36, and signals output from the respective chips are detected to conduct an electrical operation inspection.

  In addition, after the wafer chuck 34 is delivered from the alignment device 70 (Z-axis movement / rotation unit 72) to the head stage 30 (the probe card 32 side), the alignment device 70 moves to another measurement unit 16 and measures it. The contact operation is performed in the same procedure in section 16 and wafer level inspection is sequentially performed.

  As described above, according to the present embodiment, it is possible to detect the height position of the wafer chuck 34 for each step while reducing the pressure in the internal space S in steps, and calculate the overdrive amount from the detection result. Therefore, the operator can easily and accurately grasp whether or not the appropriate amount of overdrive can be secured, and a good contact can be realized between the electrode pad on the wafer W and the probe 36.

  In particular, in the present embodiment, the wafer W is positioned on the wafer W based on the amount of change in the height position of the wafer chuck 34 per step (the amount of movement of the wafer chuck 34 per step) when step pressure reduction of the internal space S is performed. The contact position at which the electrode pad of the first contact with the probe 36 starts to contact is detected, and the overdrive amount is calculated based on the contact position. Therefore, even if there is an error between the design value of the probe card 32 and the dimensions of the actual product, it is accurately understood whether or not the appropriate amount of overdrive can be secured without being affected by the error. It is possible to As a result, the electrode pad on the wafer W and the probe 36 are reliably in contact with each other, and highly reliable inspection can be performed.

  Although the prober and the probe inspection method according to the present invention have been described above in detail, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the scope of the present invention. Of course it's good.

  DESCRIPTION OF SYMBOLS 10 Prober 12 Measurement unit 14 Loader unit 16 Measurement unit 18 Load port 20 Wafer cassette 22 Operation panel 24 Transport unit 26 Transport arm 30 Head stage 32 ..... Probe card, 34 ... Wafer chuck, 34 a ... Wafer holding surface, 36 ... Probe, 38 ... Distance sensor, 40 ... Suction port, 42 ... Suction path, 44 ... Suction device, 46 ... Solenoid valve for wafer suction, 48 ... Ring Seal member 50 suction port 54 vacuum electro-pneumatic regulator 56 communication path 60 control device 70 alignment device 72 Z axis movement / rotation unit 72a wafer chuck support surface 74 X Axis moving base, 76: Y axis moving base, 78: ring seal member, 78: ring seal member, 80: suction port, 82: suction path, 84: chuck fixed Solenoid valve 86 throttle valve 88 positioning pin 90 V block 92 Z axis movement mechanism 94 rotation mechanism 100 whole control unit 102 X axis movement control unit 104 Y axis movement Control unit 106 ... Z-axis movement control unit 108 ... θ rotation control unit 110 ... Solenoid valve control unit for wafer adsorption 112 ... Solenoid valve control unit for chuck fixation 114 ... Suction control unit 115 ... 115 Overdrive amount calculation , 118 ... X-axis drive motor, 120 ... Y-axis drive motor, 122 ... Z-axis drive motor, 124 ... rotational drive motor, W ... wafer, S ... internal space

Claims (6)

A wafer chuck for holding a wafer;
A probe card provided opposite to the wafer chuck and having a probe at a position corresponding to each electrode pad of the wafer;
An annular seal member forming an internal space between the wafer chuck and the probe card;
Mechanical elevating means for detachably supporting the wafer chuck and for moving the wafer chuck up and down toward the probe card;
In a state where the inner space is formed by the seal member, a pressure reducing means for performing step pressure reduction in which pressure reduction of the inner space is divided into a plurality of steps and stepwise
Height position detection means for detecting the height position of the wafer chuck in each step when the step pressure reduction is performed;
An overdrive amount calculation unit that calculates an overdrive amount when the probe and the electrode pad are in contact with each other based on the detection result of the height position detection unit;
Prober equipped with The overdrive amount calculation means determines the height position of the wafer chuck when the height position of the wafer chuck per step changes when the step pressure reduction is performed, the probe and the electrode pad Calculating the overdrive amount with the contact position as a reference position, judging that the contact position has started to come into contact
The prober according to claim 1. The height position detection means is a noncontact distance sensor disposed at a position away from the wafer chuck.
The prober according to claim 1 or 2. In a state where an internal space is formed between the wafer chuck and the probe card, a step of depressurizing the internal space by dividing it into a plurality of steps and performing stepwise depressurization;
A height position detection step of detecting the height position of the wafer chuck at each step when the step pressure reduction is performed;
An overdrive amount calculating step of calculating an overdrive amount when the probe of the probe card contacts the electrode pad on the wafer held by the wafer chuck based on the detection result of the height position detecting step;
Probe inspection method comprising: In the overdrive amount calculation step, the height position of the wafer chuck when the height position of the wafer chuck per step changes when the step pressure reduction is performed, the probe and the electrode pad Calculating the overdrive amount with the contact position as a reference position, judging that the contact position has started to come into contact
The probe inspection method according to claim 4. The height position detection step detects the height position of the wafer chuck using a non-contact distance sensor disposed at a position separated from the wafer chuck.
The probe inspection method according to claim 4 or 5.

Images