Prober control device and prober control method

Abstract

To provide a prober control device and a prober control method that can achieve good contact between an electrode pad on a wafer and a probe without providing shutter means on a wafer chuck.SOLUTION: The prober control device controls a suction operation that reduces the pressure in a space between a wafer chuck 34 and a probe card 32 using a suction device 44 and a movement operation that brings the wafer chuck 34 and the probe card 32 closer to each other using different means from the suction device 44. The prober control device includes a control unit that sets the suction amount by the suction device 44 on the basis of the relative movement speed between the wafer chuck 34 and the probe card 32.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

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

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

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

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

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

[0007] In light of this background, for example, Patent Document 1 proposes a multi-stage prober equipped with multiple measurement units. In this prober, an alignment device that aligns the wafer and the probe card relative to each other is configured to be able to move between each measurement unit. This allows the alignment device to be shared by each measurement unit, thereby saving space and reducing costs.

[0008] Furthermore, the prober described in Patent Document 1 employs a vacuum suction method for holding the wafer chuck on the probe card side. In this vacuum suction method, the internal space (sealed space) formed between the wafer chuck and the probe card is depressurized by a depressurizing means to draw the wafer chuck toward the probe card, thereby performing a contact operation for bringing the electrode pads of each chip on the wafer into contact with each probe of the probe card. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2016-032110 A Summary of the Invention [Problem to be solved by the invention]

[0010] Incidentally, in the prober described in Patent Document 1, in order to remove the oxide film formed on the electrode pads of each chip on the wafer, before depressurization of the internal space formed between the wafer chuck and the probe card begins, the lifting mechanism of the alignment device lifts the wafer chuck toward the probe card, and each probe of the probe card is brought into contact with the electrode pads of each chip on the wafer at a predetermined pressure.

[0011] However, when the wafer chuck is raised by the lifting mechanism of the alignment device, if the internal space formed between the probe card and the wafer chuck is in a closed state (sealed state) that does not communicate with the external space, the air in the internal space is compressed instantaneously as the wafer chuck is raised, generating a strong reaction force, which may cause the probe card and the wafer to come into contact in an unintended manner. In this case, the abnormal contact between the probe card and the wafer may cause a malfunction in which the probe card or the wafer is damaged. In addition, the reaction force caused by the compression of the internal space becomes a load on the lifting mechanism of the alignment device, which may affect the moving speed of the wafer chuck relative to the probe card, and the oxide film on the electrode pads may not be sufficiently removed.

[0012] In order to solve such a problem, the prober described in Patent Document 1 employs a configuration in which a shutter means is provided in the wafer chuck, which can selectively open and close a communication passage that communicates between the internal space and the external space. According to this configuration, when the wafer chuck is raised by the lifting mechanism of the alignment device, the shutter means opens the communication passage, so that the internal space is in a connected state (non-sealed state) with the external space, and it is possible to prevent a malfunction in which the probe card or the wafer is damaged due to abnormal contact between the probe card and the wafer. In addition, during the contact operation, the wafer chuck can be raised at a desired moving speed without being affected by the above-mentioned reaction force, so it is possible to obtain a moving speed sufficient for removing the oxide film on the electrode pad.

[0013] However, although the prober described in Patent Document 1 can prevent the effects of the reaction force caused by the compression of the internal space as the wafer chuck is raised by using a shutter means provided on the wafer chuck, it has the following problems.

[0014] That is, by attaching components of the shutter means to the wafer chuck, the components become heat dissipation elements, which have an effect on the temperature distribution of the wafer chuck. In particular, when an inspection is performed in an unusual environment such as a high or low temperature, the wafer chuck is heated or cooled during the inspection, and in that case, the effect on the temperature distribution of the wafer chuck is significant. In addition, the effect on the temperature distribution of the wafer chuck may change the flatness of the mounting surface (wafer holding surface) of the wafer chuck, which causes uneven contact pressure between each probe of the probe card and the electrode pad of each chip on the wafer, which causes a decrease in the measurement accuracy of the wafer level inspection.

[0015] Furthermore, in the case where the wafer chuck is provided with a shutter means, the components of the shutter means can cause the weight balance of the wafer chuck to be lost, which can cause the transfer of the wafer chuck from the alignment device to the probe card to become unstable, and can prevent good contact from being achieved between the electrode pads on the wafer and the probes.

[0016] The present invention has been made in consideration of the above circumstances, and has an object to provide a prober and a probe inspection method that can achieve good contact between the electrode pads on the wafer and the probes without providing a shutter means on the wafer chuck. [Means for solving the problem]

[0017] In order to achieve the above object, the following invention is provided.

[0018] The prober of the first aspect of the present invention comprises a wafer chuck for holding a wafer, a probe card having a plurality of probes on a surface facing the wafer chuck, a ring-shaped sealing member for forming an internal space between the wafer chuck and the probe card, a mechanical lifting means having a wafer chuck fixing part for removably fixing the wafer chuck and for raising and lowering the wafer chuck fixed to the wafer chuck fixing part, a suction means for adsorbing and holding the wafer chuck to the probe card side by reducing the pressure in the internal space, and a suction control means for controlling the suction operation by the suction means, which starts the suction operation by the suction means before the internal space becomes sealed.

[0019] A prober according to a second aspect of the present invention is the prober of the first aspect, wherein the mechanical lifting means moves the wafer chuck towards the probe card so as to bring the probes into contact with the electrode pads of the wafer in an overdrive state.

[0020] A third aspect of the present invention relates to a prober according to the first or second aspect, wherein the suction control means sets the amount of suction by the suction means based on the moving speed of the wafer chuck by the mechanical lifting means.

[0021] A probe inspection method according to a fourth aspect of the present invention is a probe inspection method in a prober including a wafer chuck for holding a wafer, a probe card having a plurality of probes on a surface facing the wafer chuck, a ring-shaped sealing member that forms an internal space between the wafer chuck and the probe card, a mechanical lifting means having a wafer chuck fixing portion for removably fixing the wafer chuck and for raising and lowering the wafer chuck fixed to the wafer chuck fixing portion, and a suction means for adsorbing and holding the wafer chuck on the probe card side by reducing the pressure in the internal space, the method including a wafer chuck moving step for moving the wafer chuck toward the probe card by the mechanical lifting means, a pre-suction step for starting a suction operation by the suction means before the internal space becomes sealed, and a main suction step for adsorbing and holding the wafer chuck on the probe card side by reducing the pressure in the internal space by the suction means after the wafer chuck moving step is performed.

[0022] A probe inspection method according to a fifth aspect of the present invention is the fourth aspect, in which the wafer chuck moving step moves the wafer chuck toward the probe card by a mechanical lifting means so as to bring the probes into contact with the electrode pads of the wafer in an overdrive state.

[0023] A sixth aspect of the present invention relates to a probe inspection method according to the fourth or fifth aspect, wherein the pre-suction step sets the amount of suction by the suction means based on the moving speed of the wafer chuck by the mechanical lifting means. Effect of the Invention

[0024] According to the present invention, the suction operation by the suction means is started before the internal space becomes sealed, so that good contact can be achieved between the electrode pads on the wafer and the probes without providing a shutter means on the wafer chuck. [Brief description of the drawings]

[0025] [Figure 1]FIG. 1 is an external view showing the overall configuration of a prober according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a plan view showing the overall configuration of the prober according to the present embodiment; [Diagram 3] FIG. 2 is a schematic diagram showing the configuration of a measurement unit in the prober of the present embodiment; [Figure 4] FIG. 4 is a schematic diagram showing the configuration of a measurement section in the measurement unit shown in FIG. [Diagram 5] FIG. 2 is a functional block diagram showing the configuration of a control device of the prober according to the present embodiment. [Figure 6] 1 is a flowchart showing a contact operation in the prober of the present embodiment. [Figure 7] FIG. 2 is a diagram for explaining a contact operation in the prober of the present embodiment; [Figure 8] FIG. 2 is a diagram for explaining a contact operation in the prober of the present embodiment; [Figure 9] FIG. 1 is a timing chart showing an example of a contact operation in the prober of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0027] 1 and 2 are an external view and a plan view showing the overall configuration of a prober 10 according to the present embodiment.

[0028] 1 and 2, the prober 10 of this embodiment includes a loader section 14 that supplies and collects a wafer W (see FIG. 4) to be inspected, and a measurement unit 12 disposed adjacent to the loader section 14. The measurement unit 12 has a plurality of measurement sections 16, and when a wafer W is supplied from the loader section 14 to each measurement section 16, each measurement section 16 inspects the electrical characteristics of each chip on the wafer W (wafer level inspection). The wafer W inspected by each measurement section 16 is then collected by the loader section 14. The prober 10 also includes an operation panel 22, a control device 60 (see FIG. 5) to be described later, and the like.

[0029] The loader section 14 has a load port 18 on which the wafer cassette 20 is placed, and a transport unit 24 that transports the wafer W between each measuring section 16 of the measuring unit 12 and the wafer cassette 20. The transport unit 24 is provided with a transport unit drive mechanism (not shown) and is configured to be movable in the X and Z directions and rotatable in the θ direction (around the Z direction). The transport unit 24 also has a transport arm 26 that is configured to be freely extended and retracted back and forth by the transport unit drive mechanism. An adsorption pad (not shown) is provided on the upper surface of the transport arm 26, and the transport arm 26 holds the wafer W by vacuum adsorbing the back surface of the wafer W with the adsorption pad. As a result, the wafer W in the wafer cassette 20 is taken out by the transport arm 26 of the transport unit 24 and transported to each measuring section 16 of the measuring unit 12 while being held on its upper surface. The inspected wafer W is returned to the wafer cassette 20 from each measuring section 16 along the reverse path.

[0030] Fig. 3 is a schematic diagram showing the configuration of the measurement unit 12 in the prober 10 of this embodiment. Fig. 4 is a schematic diagram showing the configuration of the measurement section 16 in the measurement unit 12 shown in Fig. 3.

[0031] 3, the measurement unit 12 has a stacked structure (multi-stage structure) in which a plurality of measurement parts 16 are stacked in multiple stages, and each measurement part 16 is two-dimensionally arranged along the X direction and the Z direction. In this embodiment, as an example, four measurement parts 16 are stacked in three stages in the Z direction in the X direction.

[0032] The measurement unit 12 includes a housing (not shown) having a lattice shape in which a plurality of frames are combined in a lattice shape. This housing is formed by combining a plurality of frames extending in the X direction, Y direction, and Z direction in a lattice shape, and components of the measurement section 16 are disposed in each space formed by these frames.

[0033] Each measurement unit 16 has the same configuration, and includes a head stage 30, a probe card 32, and a wafer chuck 34, as shown in Fig. 4. Each measurement unit 16 is provided with a test head (not shown). The test head is supported above the head stage 30 by a test head holding unit (not shown).

[0034] The head stage 30 is supported by a frame member (not shown) that constitutes a part of the housing, and a probe card 32 is detachably attached and fixed to the head stage 30. The probe card 32 attached and fixed to the head stage 30 is provided so as to face a wafer holding surface 34a of a wafer chuck 34. The probe card 32 is replaced depending on the wafer W (device) to be inspected.

[0035] The probe card 32 is provided with a plurality of probes 36, such as cantilevers or spring pins, arranged corresponding to the positions of the electrode pads of each chip on the wafer W to be inspected. Each probe 36 is electrically connected to a terminal of a test head (not shown), and power and test signals are supplied from the test head to each chip via each probe 36, and output signals from each chip are detected by the test head to measure whether or not it operates normally. Note that the connection configuration between the probe card 32 and the test head is not an essential part of the present invention, so a detailed description thereof will be omitted.

[0036] The probe 36 has spring characteristics, and contacts the electrode pad with a predetermined contact pressure by raising the contact point from the tip position of the probe 36. When the probe 36 contacts the electrode pad in an overdrive state during electrical testing, the tip of the probe 36 sinks into the surface of the electrode pad and forms a needle mark on the surface of the electrode pad. Note that the overdrive state refers to a state in which the electrode pad, i.e., the surface of the wafer W, is raised by a distance α to a position higher than the tip position of the probe 36 so that the electrode pad and the probe 36 are surely in contact with each other, taking into consideration the inclination of the wafer W and the arrangement surface of the tips of the probes 36 and the variation in the tip positions of the probes 36. Note that the amount of movement by which the surface of the wafer W is further raised from the tip position (contact position) of the probe 36, i.e., the above distance α, is referred to as the overdrive amount.

[0037] The wafer chuck 34 fixes the wafer W by vacuum suction. The wafer chuck 34 has a wafer holding surface 34a on which the wafer W to be inspected is placed, and a plurality of suction ports 40 are provided on the wafer holding surface 34a (only one is shown in FIG. 4). The suction port 40 is connected to a suction device (vacuum source) 44 such as a vacuum pump via a suction path 42 formed inside the wafer chuck 34. A wafer suction solenoid valve 46 is provided on the suction path connecting the suction device 44 and the suction path 42. The wafer suction solenoid valve 46 is controlled by a wafer suction solenoid valve control unit 110 (see FIG. 5).

[0038] An elastic ring-shaped seal member (chuck seal rubber) 48 is provided outside the wafer holding surface 34a of the wafer chuck 34 so as to surround the wafer W held on the wafer holding surface 34a. When the wafer chuck 34 is moved (raised) toward the probe card 32 by the Z-axis moving / rotating unit 72 described below, the ring-shaped seal member 48 comes into contact with the lower surface of the head stage 30, thereby forming an internal space S (see FIG. 7) surrounded by the wafer chuck 34, the probe card 32, and the ring-shaped seal member 48. The ring-shaped seal member 48 is an example of an annular seal member of the present invention.

[0039] The head stage 30 is provided with a suction port 50 for reducing the pressure of 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 path 52 formed inside the head stage 30. A vacuum electro-pneumatic regulator 54 is provided in the 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 (degree of vacuum) 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 suction device 44 and the vacuum electro-pneumatic regulator 54 are an example of the suction means of the present invention.

[0040] Inside the wafer chuck 34, a heating / cooling mechanism (not shown) is provided as a heating / cooling source so that the electrical characteristics of the wafer W to be inspected can be inspected at a high temperature (for example, up to 150° C.) or at a low temperature (for example, down to −40° C.). As the heating / cooling mechanism, any suitable known heater / cooler can be used, and various types are conceivable, such as a double-layer structure with a heating layer of a surface heater and a cooling layer with a passage for a cooling fluid, or a single-layer heating / cooling device with a cooling pipe wrapped around a heater embedded in a thermal conductor. Also, instead of electrical heating, a device that circulates a thermal fluid or a Peltier element may be used.

[0041] The wafer chuck 34 is detachably supported and fixed to an alignment device 70 described later. The alignment device 70 moves the wafer chuck 34 in the X, Y, Z, and θ directions to perform relative alignment between the wafer W held by the wafer chuck 34 and the probe card 32.

[0042] The alignment device 70 includes a Z-axis moving / rotating unit 72 that detachably supports and fixes the wafer chuck 34 and moves the wafer chuck 34 in the Z-axis direction while rotating it in the θ direction about the Z axis, an X-axis moving stage 74 that supports the Z-axis moving / rotating unit 72 and moves it in the X-axis direction, and a Y-axis moving stage 76 that supports the X-axis moving stage 74 and moves it in the Y-axis direction.

[0043] The Z-axis moving / rotating unit 72, the X-axis moving stage 74, and the Y-axis moving stage 76 are each configured to move or rotate the wafer chuck 34 in a predetermined direction by a mechanical driving mechanism including at least a motor. The mechanical driving mechanism may be, for example, a ball screw driving mechanism that combines a servo motor and a ball screw. The mechanical driving mechanism is not limited to the ball screw driving mechanism, and may be a linear motor driving mechanism or a belt driving mechanism. The Z-axis moving / rotating unit 72, the X-axis moving stage 74, and the Y-axis moving stage 76 are configured to change the moving distance, moving direction, moving speed, and acceleration of the wafer chuck 34 by each control unit described later. In this embodiment, specifically, the following configuration is provided.

[0044] The Z-axis moving / rotating unit 72 is an example of the mechanical lifting means of the present invention, and includes a Z-axis drive motor 122 (e.g., a stepping motor, a servo motor, a linear motor, etc.) (see FIG. 5) for moving the wafer chuck 34 in the Z-axis direction, and a Z-axis encoder (e.g., a rotary encoder, a linear scale, etc.) (not shown) for detecting the movement distance of the wafer chuck 34 in the 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), which will be described later, and drives the wafer chuck 34 to move to a target position at a desired movement speed or acceleration. In addition, the Z-axis encoder outputs an encoder signal in accordance with the movement of the wafer chuck 34.

[0045] Furthermore, the Z-axis moving / rotating unit 72 includes a rotary drive motor 124 (e.g., a stepping motor, a servo motor, a linear motor, etc.) (see FIG. 5) for rotating the wafer chuck 34 in the θ direction, and a rotary encoder (e.g., a rotary encoder, etc.) (not shown) for detecting the rotation angle of the wafer chuck 34 in the θ direction. The rotary drive motor 124 is controlled based on a motor control signal from a θ rotation control unit 108 (see FIG. 5), which will be described later, and drives the wafer chuck 34 to move to a target position at a desired rotation speed or acceleration. Furthermore, the rotary encoder outputs an encoder signal in accordance with the rotation of the wafer chuck 34.

[0046] The X-axis moving stage 74 is equipped with an X-axis drive motor 118 (e.g., a stepping motor, a servo motor, a linear motor, etc.) (see FIG. 5) for moving the wafer chuck 34 in the X-axis direction, and an X-axis encoder (e.g., a rotary encoder, a linear scale, etc.) (not shown) for detecting the movement distance of the wafer chuck 34 in the X-axis direction. The X-axis drive motor 118 is controlled based on a motor control signal from an X-axis movement control unit 102 (see FIG. 5), which will be described later, and drives the wafer chuck 34 to move to a target position at a desired movement speed or acceleration. In addition, the X-axis encoder outputs an encoder signal in accordance with the movement of the wafer chuck 34.

[0047] The Y-axis moving stage 76 is equipped with a Y-axis drive motor 120 (e.g., a stepping motor, a servo motor, a linear motor, etc.) (see FIG. 5) for moving the wafer chuck 34 in the Y-axis direction, and a Y-axis encoder (e.g., a rotary encoder, a linear scale, etc.) (not shown) for detecting the movement distance of the wafer chuck 34 in the Y-axis direction. The Y-axis drive motor 120 is controlled based on a motor control signal from a Y-axis movement control unit 104 (see FIG. 5), which will be described later, and drives the wafer chuck 34 to move to a target position at a desired movement speed or acceleration. In addition, the Y-axis encoder outputs an encoder signal in accordance with the movement of the wafer chuck 34.

[0048] The alignment device 70 is provided for each stage (see FIG. 3), and is configured to be movable between the multiple measurement units 16 arranged on each stage by an alignment device drive mechanism (not shown). That is, the alignment device 70 is shared between the multiple measurement units 16 (four in this example) arranged on the same stage, and moves between the multiple measurement units 16 arranged on the same stage. The alignment device 70 that has moved to each measurement unit 16 is fixed in a predetermined position by a positioning and fixing device (not shown), and the wafer chuck 34 is moved in the X, Y, Z, and θ directions to perform relative alignment between the wafer W held on the wafer chuck 34 and the probe card 32. Although not shown, the alignment device 70 includes a needle position detection camera and a wafer alignment camera in order to detect the relative positional relationship between the electrode pads of each chip of the wafer W held on the wafer chuck 34 and the probes 36. The alignment device drive mechanism is configured by a mechanical drive mechanism such as a ball screw drive mechanism, a linear motor drive mechanism, and a belt drive mechanism.

[0049] A ring-shaped seal member (Z-axis seal rubber) 78 having elasticity and formed in an annular shape along the outer periphery is provided on the wafer chuck support surface 72a of the Z-axis moving / rotating part 72 constituting the upper surface of the alignment device 70. A suction port 80 is provided on the inner side of the ring-shaped seal member 78 of the wafer chuck support surface 72a. The suction port 80 is connected to the suction device 44 via a suction path 82 formed inside the wafer chuck 34. A chuck fixing solenoid valve 84 and a throttle valve 86 are provided in the suction path connecting the suction device 44 and the suction path 82, in this 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), which will be described later. The wafer chuck support surface 72a of the Z-axis moving / rotating part 72 is an example of a wafer chuck fixing unit of the present invention. The suction port 80 provided on the wafer chuck support surface 72a is an example of a component of the wafer chuck fixing unit.

[0050] Positioning pins 88 are provided on the outer side of the ring-shaped seal member 78 on the wafer chuck support surface 72a of the Z-axis moving / rotating section 72 so that the relative positional relationship of the wafer chuck 34 with respect to the alignment device 70 is always constant. The positioning pins 88 are provided at three locations at equal intervals along the circumferential direction centered on the central axis of the wafer chuck 34 (only two are shown in FIG. 4). V-blocks 90, which are positioning members, are provided on the lower surface of the wafer chuck 34 at positions corresponding to the positioning pins 88. When the wafer chuck 34 is attracted and fixed by vacuum suction, the corresponding positioning pins 88 are engaged with the V-grooves of the V-blocks 90, thereby restricting the movement of the wafer chuck 34 in the horizontal direction (X direction and Y direction), thereby positioning the alignment device 70 and the wafer chuck 34 relative to each other.

[0051] In this embodiment, the alignment device 70 fixes the wafer chuck 34 by vacuum adsorption, but any fixing means other than vacuum adsorption may be used as long as it is capable of fixing the wafer chuck 34, and for example, the wafer chuck 34 may be fixed by mechanical means, etc.

[0052] FIG. 5 is a functional block diagram showing the configuration of the control device 60 of the prober 10 of the present embodiment.

[0053] The control device 60 stores data necessary for the operation and processing of each part of the prober 10. The control device 60 is realized by a general-purpose computer such as a personal computer or a microcomputer.

[0054] The control device 60 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, etc. In the control device 60, various programs such as a control program stored in the ROM are loaded into the RAM, and the programs loaded into the RAM are executed by the CPU, thereby realizing the functions of the various parts in the control device 60 shown in Fig. 5, and various arithmetic processing and control processing are executed via the input / output interface.

[0055] As shown in FIG. 5, the control device 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, a wafer suction solenoid valve control unit 110, a chuck fixing solenoid valve control unit 112, and a suction control unit 114.

[0056] The overall control unit 100 performs overall control of each unit constituting the prober 10. Specifically, the overall control unit 100 controls the operation (contact operation) of bringing the electrode pads of each chip of the wafer W to be inspected into contact with each probe 36 of the probe card 32. In addition to the contact operation, the overall control unit 100 also performs movement control for moving the alignment device 70 between each measurement unit 16, and control of the operation of wafer-level inspection by the test head. Note that controls other than the contact operation are not characteristic of the present invention, and therefore detailed description thereof will be omitted.

[0057] The X-axis movement control unit 102 controls the drive of an X-axis drive motor 118 provided in the X-axis movement stage 74 to move the X-axis movement stage 74 in the X-axis direction, thereby moving the wafer chuck 34 in the X-axis direction. The Y-axis movement control unit 104 controls the drive of a Y-axis drive motor 120 provided in the Y-axis movement stage 76 to move the Y-axis movement stage 76 in the Y-axis direction, thereby moving the wafer chuck 34 in the Y-axis direction. The Z-axis movement control unit 106 controls the drive of a Z-axis drive motor 122 provided in the Z-axis movement / rotation unit 72 to raise and lower the Z-axis movement / rotation unit 72, thereby moving the wafer chuck 34 in the Z-axis direction. The θ rotation control unit 108 controls the drive of a 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 moving the wafer chuck 34 in the θ direction. Rotate in the direction.

[0058] The wafer suction solenoid valve control unit 110 controls the ON / OFF (open / close) of the wafer suction solenoid valve 46 to adjust the suction pressure by the suction port 40 and selectively switch between fixed and unfixed states of the wafer W to the wafer chuck 34.

[0059] The chuck fixing solenoid valve control unit 112 controls the ON / OFF (open / close) of the chuck fixing solenoid valve 84 to adjust the suction pressure by the suction port 80, and selectively switches between fixed and unfixed states of the wafer chuck 34 relative to the Z-axis moving / rotating unit 72.

[0060] The suction control unit 114 controls the operation of the vacuum electropneumatic regulator 54 to steplessly adjust the internal pressure (degree of vacuum) of the internal space S. The suction control unit 114 is an example of the suction control means of the present invention.

[0061] Next, a contact operation (one example of a probe inspection method) in the prober 10 of this embodiment will be described with reference to Figures 6 to 9. This operation is performed under the control of the overall control unit 100.

[0062] FIG. 6 is a flow chart showing a contact operation in the prober 10 of this embodiment. FIGS. 7 and 8 are diagrams for explaining the contact operation in the prober 10 of this embodiment. FIG. 9 is a timing chart showing an example of a contact operation in the prober 10 of this embodiment. Note that the time width of the timing chart shown in FIG. 9 is expressed to simplify the drawing and differs from the actual time. Also, the "Z-axis height" in FIG. 9 indicates the height position of the Z-axis moving / rotating part 72 (specifically, the position of the wafer chuck support surface 72a in the Z-axis direction). Also, the "chuck height" in FIG. 9 indicates the height position of the wafer chuck 34 (specifically, the position of the wafer holding surface 34a in the Z-axis direction).

[0063] (Pre-action) The preliminary operation of the contact operation will be described.

[0064] First, as a preliminary operation for the contact operation, the alignment device 70 is moved to the measurement section 16 where the inspection will be performed, and then the wafer chuck 34 is transferred to the alignment device 70 while being positioned and fixed by a positioning and fixing device (not shown). Note that the transfer operation of the wafer chuck 34 before the start of the contact operation is not an essential part of the present invention, so a detailed description thereof will be omitted.

[0065] (Step S10: Wafer chuck fixing process) After the wafer chuck 34 is delivered to the alignment device 70, the chuck fixing solenoid valve control unit 112 turns on (open) the chuck fixing solenoid valve 84, as indicated by reference numeral 500A in Fig. 7, and adsorbs and fixes the wafer chuck 34 to the wafer chuck support surface 72a (see Fig. 4) of the Z-axis moving / rotating unit 72 (time T1 in Fig. 9). At this time, the positioning pin 88 of the Z-axis moving / rotating unit 72 is engaged with the V-groove of the V-block 90 of the wafer chuck 34, thereby performing relative positioning between the alignment device 70 and the wafer chuck 34.

[0066] Thereafter, when the wafer W is supplied (loaded) onto the wafer chuck 34 supported and fixed by the alignment device 70, the wafer adsorption solenoid valve control unit 110 turns the wafer adsorption solenoid valve 46 ON (open state) and adsorbs and fixes the wafer W onto the wafer holding surface 34a (see FIG. 4) (time T2 in FIG. 9).

[0067] (Step S12: Alignment process) Next, under the control of the overall control unit 100, the X-axis movement control unit 102, the Y-axis movement control unit 104, and the θ rotation control unit 108 control the X-axis drive motor 118, the Y-axis drive motor 120, and the rotation drive motor 124 based on the results of imaging by the needle position detection camera and the wafer alignment camera, to perform relative alignment between the wafer W held by the wafer chuck 34 and the probe card 32.

[0068] (Step S14: Pre-suction process) Next, the suction control unit 114 controls the operation of the vacuum electropneumatic regulator 54 to start suction through the suction port 50 (time T3 in FIG. 9).

[0069] In this embodiment, when controlling the operation of the vacuum electropneumatic regulator 54, the suction control unit 114 controls the amount of suction based on the moving speed (rising speed) of the wafer chuck 34 in a Z-axis rising process described later.

[0070] Specifically, the area of ​​the surface (the adsorption surface) surrounded by the ring-shaped seal member 48 is defined as A [mm 2 ], and the moving speed of the wafer chuck 34 is V z [mm / s], the volume (capacity) V [mm 3 / s] is expressed by the following equation, so the suction volume is controlled so that it is at least volume V.

[0071] V = A V z As a result, when the wafer chuck 34 is moved toward the probe card 32, even after the ring-shaped sealing member 48 comes into contact with the head stage 30, the gas corresponding to the decrease in volume (capacity) of the internal space S caused by the movement of the wafer chuck 34 is sucked in, so that no reaction force is generated due to compression of the internal space S.

[0072] The pre-suction step only needs to be started at least before the ring-shaped seal member 48 comes into contact with the head stage 30 (see reference numeral 500B in FIG. 7) in the Z-axis raising step described below. For example, the pre-suction step may be started between the wafer chuck fixing step and the alignment step, or may be started prior to the wafer chuck fixing step. The pre-suction step may also be started simultaneously with the wafer chuck fixing step or the alignment step.

[0073] (Step S16: Z-axis rising process) Next, as indicated by reference numerals 500B and 500C 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 moving the wafer chuck 34 toward the probe card 32 (times T4 to T6 in FIG. 9).

[0074] Specifically, the Z-axis movement control unit 106 raises the wafer chuck 34 so that the wafer chuck 34 moves from a predetermined height position (standby position) H0 to a height position H1 where the ring-shaped seal member 48 contacts the head stage 30 (see reference numeral 500B in FIG. 7), and further raises the wafer chuck 34 to a position H2 that is at least higher than the tip positions (contact positions) of the probes 36 (see reference numeral 500C in FIG. 7). As a result, the probes 36 of the probe card 32 contact the electrode pads of the chips on the wafer W in an overdrive state.

[0075] Here, in this embodiment, when the wafer chuck 34 is moved toward the probe card 32 as described above, when the ring-shaped sealing member 48 comes into contact with the head stage 30, the internal space S formed between the wafer chuck 34 and the probe card 32 becomes sealed and isolated from the outside.

[0076] At this time, in this embodiment, the pre-suction step is started before the ring-shaped seal member 48 comes into contact with the head stage 30 (see reference numeral 500B in FIG. 7) in the Z-axis lifting step, so that even after the ring-shaped seal member 48 comes into contact with the head stage 30 and the internal space S is sealed, there is no effect of the reaction force due to compression of the internal space S. Therefore, it is possible to prevent abnormal contact between the probe card 32 and the wafer W, and to stably move the wafer chuck 34 toward the probe card 32 at a sufficient moving speed to remove the oxide film on the electrode pads.

[0077] In the Z-axis lifting step, the height to which the wafer chuck 34 is lifted by the Z-axis moving / rotating unit 72 is preferably 30 to 70% (more preferably 40 to 60%) of the appropriate overdrive amount (appropriate OD position) of the probe card 32 from the tip position (contact position) of the probe 36. The Z-axis lifting step is an example of a wafer chuck moving step of the present invention.

[0078] (Step S18: Main suction process) Next, as shown by reference numeral 500D in FIG. 8, the suction control unit 114 controls the operation of the vacuum electropneumatic regulator 54 to continue suction from the suction port 50 following the pre-suction step, thereby continuously reducing the pressure in the internal space S (time T7 in FIG. 9). At this time, the suction control unit 114 sets a set pressure (target pressure) such that the wafer chuck 34 rises to the appropriate overdrive amount (appropriate OD position H3) of the probe card 32 when the fixation of the wafer chuck 34 by the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72 is released, and adjusts the internal pressure of the internal space S to the set pressure. The set pressure of the internal space S may be obtained empirically or experimentally, or may be obtained from a design value. For example, the set pressure can be determined from the reaction force (the reaction force when the probe 36 is crushed) received from the probe 36 when the wafer chuck 34 rises to the appropriate overdrive amount of the probe card 32, and the total number of probes 36 provided on the probe card 32. If the total needle pressure of the probe card 32 (the sum of the pressures received from the probes 36) is known, the necessary negative pressure can be obtained as the set pressure of the internal space S by dividing it by the area of ​​the surface (adsorption surface) surrounded by the ring-shaped seal member 48. However, it is necessary to set the set pressure of the internal space S taking into account the weight of the wafer chuck 34 and the reaction force caused by crushing the ring-shaped seal member 48.

[0079] In this embodiment, the pre-suction process and the main suction process are performed consecutively, but this is not limited to the above. The pre-suction process may be temporarily terminated before the main suction process is started, and then the main suction process may be started.

[0080] (Step S20: Judgment step) Next, the suction control unit 114 judges whether the internal pressure (pressure value P1) of the internal space S has reached the set pressure (pressure value P2) set by the vacuum electro-pneumatic regulator 54. This judgment is repeated until the internal pressure (pressure value P1) reaches the set pressure (pressure value P2), and when the set pressure (pressure value P2) is reached, the process proceeds to the next step S22. As a result, when the internal pressure of the internal space S is stabilized at the set pressure, a wafer chuck fixation release step (step S22) described later is performed. The internal pressure of the internal space S may be directly detected by a pressure sensor provided in the wafer chuck 34 or the head stage 30, for example, or may be detected by a pressure sensor built into or connected to the vacuum electro-pneumatic regulator 54.

[0081] (Step S22: Wafer chuck release process) Next, as indicated by the symbol 500E in FIG. 8, the chuck fixing solenoid valve control unit 112 turns the chuck fixing solenoid valve 84 OFF (closed state) and releases the fixation of the wafer chuck 34 by the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72 (time T8 in FIG. 9).

[0082] At this time, the internal pressure of the internal space S is adjusted to the set pressure by the vacuum electropneumatic regulator 54, so when the fixation of the wafer chuck 34 by the Z-axis moving / rotating unit 72 is released, the wafer chuck 34 leaves the Z-axis moving / rotating unit 72 and is drawn toward the probe card 32 to the proper OD position H3 (T8 to T9 in FIG. 9). As a result, the electrode pads of each chip of the wafer W to be inspected and each probe 36 of the probe card 32 are reliably contacted with a predetermined contact pressure without being affected by the inclination of the wafer W and the arrangement surface of the tips of the probes 36 and the variation in the tip positions of the probes 36.

[0083] In this manner, in this embodiment, the wafer chuck 34 is released from its fixed state after the depressurization of the internal space S begins. Therefore, at the moment of switching between these processes, the wafer chuck 34 is no longer in a state where it is not fixed to either side (a free state), and the transfer operation of the wafer chuck 34 can be performed stably.

[0084] In this embodiment, the suction path connecting the suction path 82 of the Z-axis moving / rotating part 72 and the chuck fixing solenoid valve 84 is provided with a throttle valve 86, so that even if the wafer chuck 34 is released from the fixed position after the internal space S is depressurized, the negative pressure on the lower side (the Z-axis moving / rotating part 72 side) of the wafer chuck 34 is not suddenly lost. Therefore, when the wafer chuck 34 is pulled from both the upper and lower sides (i.e., both sides of the Z-axis moving / rotating part 72 and the probe card 32), the constraint from the lower side (i.e., the fixing force due to suction from the Z-axis moving / rotating part 72) is not suddenly lost, so that abnormal vibrations and abnormal contacts caused by the sudden movement of the wafer chuck 34 can be reduced. Therefore, the wafer chuck 34 can be prevented from suddenly coming off the Z-axis moving / rotating part 72 when the wafer chuck fixing release step is performed, so that the transfer operation of the wafer chuck 34 can be performed more stably.

[0085] In this embodiment, as an example, a configuration has been shown in which a throttle valve 86 is provided in the suction path connecting the suction path 82 of the Z-axis moving / rotating unit 72 and the chuck fixing solenoid valve 84. However, it is sufficient that the throttle valve 86 is provided in the path connecting the suction port 80 of the Z-axis moving / rotating unit 72 and the suction device 44. For example, the throttle valve 86 may be provided in the suction path 82 of the Z-axis moving / rotating unit 72.

[0086] (Step S24: Z-axis lowering process) Next, as indicated by reference numeral 500F in FIG. 8, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to lower the Z-axis movement / rotation unit 72 to a predetermined height position (standby position) (times T10 to T11 in FIG. 9).

[0087] When the wafer chuck 34 is transferred from the alignment device 70 (Z-axis moving / rotating unit 72) to the head stage 30 (probe card 32 side) in the above manner, each probe 36 of the probe card 32 comes into contact with the electrode pad of each chip on the wafer W with uniform contact pressure, and the wafer-level inspection is ready to begin. After that, power and test signals are supplied from the test head to each chip on the wafer W via each probe 36, and an electrical operation inspection is performed by detecting the signal output from each chip.

[0088] After the wafer chuck 34 is transferred from the alignment device 70 (Z-axis movement / rotation section 72) to the head stage 30 (probe card 32 side), the alignment device 70 moves to another measurement section 16, where a contact operation is performed in a similar procedure, and wafer-level inspections are performed sequentially.

[0089] Next, the effects of this embodiment will be described.

[0090] According to this embodiment, the pre-suction step is started before the ring-shaped seal member 48 comes into contact with the head stage 30 (see reference numeral 500B in FIG. 7) in the Z-axis rising step. Therefore, when the wafer chuck 34 is moved toward the probe card 32, even if the ring-shaped seal member 48 comes into contact with the head stage 30 and the internal space S is sealed, the wafer chuck 34 is not affected by the reaction force due to the compression of the internal space S. Therefore, since no excessive reaction force (a reaction force that tries to return the wafer chuck 34 to its original position) is generated in the wafer chuck 34, abnormal contact between the probe card 32 and the wafer W can be prevented, and the probe card 32 and the wafer W can be prevented from being damaged. In addition, the wafer chuck 34 can be moved toward the probe card 32 stably, efficiently, and accurately at a sufficient moving speed to remove the oxide film on the electrode pad. Therefore, good contact can be achieved between the electrode pads on the wafer W and the probes 36 without providing a shutter means in the wafer chuck 34.

[0091] In addition, in this embodiment, since there is no need to provide the wafer chuck 34 with a shutter means, the wafer chuck 34 does not need to be provided with components of the shutter means that act as heat dissipation elements, and the influence on the temperature distribution of the wafer chuck 34 can be eliminated. Furthermore, the elimination of the influence on the temperature distribution of the wafer chuck 34 improves the flatness of the wafer holding surface 34a of the wafer chuck 34. This allows the parallelism between the wafer W and the probe card 32 to be improved, and wafer level inspection can be performed with high accuracy. Furthermore, the number of components mounted on the wafer chuck 34 can be reduced, making it easier to balance the weight of the wafer chuck 34. As a result, the contact operation by the vacuum suction method can be stably performed without disrupting the weight balance of the wafer chuck 34.

[0092] In this embodiment, the Z-axis moving / rotating unit 72 may move the wafer chuck 34 up and down (Z direction) to bring the electrode pads on the wafer W into contact with the probes 36 multiple times in an overdrive state. The Z-axis moving / rotating unit 72 in this embodiment is configured with a mechanical driving mechanism including at least a motor (Z-axis driving motor 122), so that the moving distance and moving speed of the wafer chuck 34 can be adjusted with high precision. In addition, the Z-axis moving / rotating unit 72 can move the wafer chuck 34 at a moving speed that is sufficiently faster than the case where the wafer chuck 34 is moved toward the probe card 32 by reducing the pressure of the internal space S. Therefore, when the electrode pads on the wafer W are brought into contact with the probes 36, the oxide film (insulator) on the electrode pads can be removed by the contact of the probes 36, and good contact can be achieved between the electrode pads on the wafer W and the probes 36 without damaging the wafer W.

[0093] Furthermore, in this embodiment, the fixation of the wafer chuck 34 by the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72 is released at a timing (second timing; time T8 in FIG. 9) that is later than the timing (first timing; time T7 in FIG. 9) at which the main suction process (pressure reduction of the internal space S) is started. Therefore, at the moment of switching between these processes, the unstable state (free state) in which the wafer chuck 34 is not fixed to either side is eliminated, and the transfer operation of the wafer chuck 34 can be performed stably.

[0094] Furthermore, in this embodiment, a throttle valve 86 that limits the flow rate of gas is provided in the path connected to the suction port 80 of the Z-axis moving / rotating section 72. This makes it possible to prevent the wafer chuck 34 from suddenly detaching from the Z-axis moving / rotating section 72 when the chuck fixing solenoid valve 84 is turned OFF (when open to the atmosphere), thereby making it possible to perform the transfer operation of the wafer chuck 34 more stably.

[0095] The prober and the probe inspection method according to the present invention have been described in detail above. However, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0096] 10... prober, 12... measurement unit, 14... loader section, 16... measurement section, 18... load port, 20... wafer cassette, 22... operation panel, 24... transfer unit, 26... transfer arm, 30... head stage, 32... probe card, 34... wafer chuck, 34a... wafer holding surface, 36... probe, 40... suction port, 42... suction path, 44... suction device, 46... solenoid valve for wafer suction, 48... ring-shaped seal member, 50... suction port, 54... vacuum electro-pneumatic regulator, 56... communication path, 60... control device, 70... alignment device, 72... Z-axis moving / rotating section, 72a... wafer chuck support surface, 74... X-axis moving stage, 76 ...Y-axis moving stage, 78...ring-shaped seal member, 78...ring-shaped seal member, 80...suction port, 82...suction path, 84...electromagnetic valve for fixing chuck, 86...throttle valve, 88...positioning pin, 90...V-block, 92...Z-axis moving mechanism, 94...θ rotation mechanism, 100...overall control unit, 102...X-axis moving control unit, 104...Y-axis moving control unit, 106...Z-axis moving control unit, 108...θ rotation control unit, 110...electromagnetic valve for suction of wafer, 112...electromagnetic valve for fixing chuck, 114...suction control unit, 118...X-axis driving motor, 120...Y-axis driving motor, 122...Z-axis driving motor, 124...rotation driving motor, W...wafer, S...internal space

Claims

1. A prober control device that controls a suction operation for reducing the pressure of a space between a wafer chuck and a probe card by a suction means, and a movement operation for bringing the wafer chuck and the probe card relatively closer to each other by a means different from the suction means, a control unit that sets a suction amount by the suction means based on a relative moving speed between the wafer chuck and the probe card; Prober control device.

2. The suction amount is determined based on the moving speed so that gas equivalent to a volume reduction of the space caused by the moving operation is sucked in. Prober control device.

3. A prober control method for controlling a suction operation for reducing the pressure of a space between a wafer chuck and a probe card by a suction means, and a movement operation for bringing the wafer chuck and the probe card relatively closer to each other by a means different from the suction means, comprising: a suction amount by the suction means is set based on a relative moving speed between the wafer chuck and the probe card; A control method for a prober.

4. The suction amount is determined based on the moving speed so that gas equivalent to a volume reduction of the space caused by the moving operation is sucked in. A control method for a prober.

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