Prober

Abstract

To provide a prober that can achieve good contact between an electrode pad on a wafer and a probe without damaging the wafer.SOLUTION: In a prober 10, in which a vacuum suction method is adopted to hold a wafer chuck 34 on a probe card 32 side, after moving the wafer chuck 34 toward the probe card 32 to a contact position using a Z-axis movement and rotation unit 72, an internal space is depressurized using a vacuum electropneumatic regulator 54 to move the wafer chuck 34 to an appropriate overdrive position.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, 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 lifting mechanism of the alignment device brings each probe of the probe card into contact with the electrode pad of each chip on the wafer, depending on the degree of so-called overdrive, more contact pressure than necessary may be applied when the internal space is reduced in pressure, which may result in damage to the wafer.

[0012] 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 damaging the wafer. [Means for solving the problem]

[0013] In order to achieve the above object, the following invention is provided.

[0014] A prober according to a first aspect of the present invention comprises a wafer chuck for holding a wafer, a probe card having a plurality of probes on a surface facing the wafer chuck, an annular sealing member 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 on the probe card side by reducing the pressure in the internal space, a lifting control means for controlling the lifting operation by the mechanical lifting means, the lifting control means moving the wafer chuck to a contact position where the probes contact the electrode pads of the wafer, and a suction control means for controlling the suction operation by the suction means, the suction control means moving the wafer chuck from the contact position to an overdrive position where the probes contact the electrode pads of the wafer in an overdrive state.

[0015] A prober according to a second aspect of the present invention is the first aspect, wherein the suction control means starts the suction operation by the suction means before the internal space is sealed.

[0016] 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.

[0017] 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, an annular sealing member 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, and a suction means for adsorbing and holding the wafer chuck on the probe card side by reducing the pressure of the internal space, the method including a step of moving the wafer chuck toward the probe card by the mechanical lifting means, the wafer chuck moving step of moving the wafer chuck to a contact position where the probes contact the electrode pads of the wafer, and a step of reducing the pressure of the internal space by the suction means, the suction step of moving the wafer chuck from the contact position to an overdrive position where the probes contact the electrode pads of the wafer in an overdrive state.

[0018] A probe inspection method according to a fifth aspect of the present invention is the probe inspection method of the fourth aspect, wherein the suction step is started before the internal space is sealed.

[0019] A sixth aspect of the present invention relates to a probe inspection method according to the fourth or fifth aspect, wherein the 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

[0020] According to the present invention, good contact can be achieved between the electrode pads on the wafer and the probes without damaging the wafer. [Brief description of the drawings]

[0021] [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. [Figure 10] FIG. 11 is a timing chart showing another example of the contact operation in the prober of the present embodiment. [Figure 11] FIG. 11 is a timing chart showing another example of the contact operation in the prober of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0023] 1 and 2 are an external view and a plan view showing the overall configuration of a prober 10 according to the present embodiment.

[0024] 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.

[0025] 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.

[0026] 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 shown in Fig. 3.

[0027] 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.

[0028] 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.

[0029] 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).

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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).

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] FIG. 5 is a functional block diagram showing the configuration of the control device 60 of the prober 10 of the present embodiment.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] The X-axis movement control unit 102 controls the drive of the X-axis drive motor 118 provided on the X-axis moving stage 74 to move the X-axis moving stage 74 in the X-axis direction, thereby moving the wafer chuck 34 in the X-axis direction. The Y-axis movement control unit 104 controls the drive of the Y-axis drive motor 120 provided on the Y-axis moving stage 76 to move the Y-axis moving stage 76 in the Y-axis direction, thereby moving the wafer chuck 34 in the Y-axis direction. The Z-axis movement control unit 106 is an example of the elevation control means of the present invention, and controls the drive of the Z-axis drive motor 122 provided on the Z-axis moving and rotating unit 72 to elevate and lower the Z-axis moving and rotating unit 72, thereby moving the wafer chuck 34 in the Z-axis direction. The θ rotation control unit 108 controls the drive of the rotation drive motor 124 provided on the Z-axis moving and rotating unit 72 to rotate the Z-axis moving and rotating unit 72 in the θ direction, thereby rotating the wafer chuck 34 in the θ direction.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] FIG. 6 is a flow chart showing the 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 the contact operation in the prober 10 of this embodiment. Note that "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). Also, "chuck suction pressure" in FIG. 9 indicates the absolute value of the suction pressure (negative pressure) applied to the suction port 50 when the suction control unit 114 controls the operation of the vacuum electropneumatic regulator 54. Also, "Z-axis height" in FIG. 9 indicates the height position of the Z-axis moving / rotating unit 72 (specifically, the position of the wafer chuck support surface 72a in the Z-axis direction).

[0059] (Pre-action) The preliminary operation of the contact operation will be described.

[0060] 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.

[0061] (Step S10: Wafer chuck fixing process) After the wafer chuck 34 is delivered to the alignment device 70, as indicated by reference numeral 500A in Fig. 7, the chuck fixing solenoid valve control unit 112 turns on (open) the chuck fixing solenoid valve 84 to adsorb and fix the wafer chuck 34 to the wafer chuck support surface 72a (see Fig. 4) of the Z-axis moving / rotating unit 72. 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.

[0062] 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).

[0063] (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.

[0064] (Step S14: 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 T1 in FIG. 9). As a result, the chuck suction pressure (negative pressure applied to the suction port 50) gradually increases from pressure value 0 toward set pressure value P1. Note that it is preferable that the timing at which the set pressure value P1 is reached is at least before or simultaneously with the timing at which a wafer chuck release process described below starts (time T3 in FIG. 9). This allows the wafer chuck 34 to be stably transferred from the alignment device 70 (Z-axis moving / rotating unit 72) to the head stage 30 (probe card 32 side).

[0065] Here, the above-mentioned set pressure value P1 is set to a value at which the wafer chuck 34 rises to a proper overdrive amount (proper OD position H2) of the probe card 32 when a wafer chuck fixing release process described later is performed in a state in which an internal space S (sealed space) is formed between the probe card 32 and the wafer chuck 34. The suction control unit 114 controls the operation of the vacuum electro-pneumatic regulator 54 so that a pressure (negative pressure) of the set pressure value P1 (negative pressure) is applied to the suction port 50.

[0066] The set pressure value P1 may be empirically or experimentally obtained, or may be obtained from a design value. For example, the set pressure value P1 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 is raised to the appropriate overdrive amount of the probe card 32, and the total number of the probes 36 provided on the probe card 32. If the total needle pressure of the probe card 32 (the sum of the pressures received from the probes 36) is known, the negative pressure to be applied to the internal space S can be obtained by dividing it by the area of ​​the surface (the suction surface) surrounded by the ring-shaped seal member 48. However, it is necessary to set the set pressure value P1 taking into account the weight of the wafer chuck 34 and the reaction force caused by crushing the ring-shaped seal member 48.

[0067] (Step S16: Z-axis rising process) 7, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to raise the Z-axis moving / rotating unit 72, thereby moving the wafer chuck 34 toward the probe card 32 (times T2 to T3 in FIG. 9). Specifically, the wafer chuck 34 is moved from a predetermined height position (standby position) H0 to the tip position (contact position) H1 of the probe 36. The Z-axis raising step is an example of a wafer chuck moving step of the present invention.

[0068] When the Z-axis lifting step is performed, as the wafer chuck 34 lifts, the ring-shaped seal member 48 comes into contact with the head stage 30 before the wafer chuck 34 reaches the contact position H1. At this time, the internal space S formed between the wafer chuck 34 and the probe card 32 is sealed off from the outside.

[0069] Here, in this embodiment, when the wafer chuck 34 is moved toward the probe card 32 in the Z-axis lifting step, the suction step started before the Z-axis lifting step is performed, 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, the wafer chuck 34 is not affected by the reaction force due to compression of the internal space S. This makes it 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.

[0070] In addition, in this embodiment, when the Z-axis rising process is performed, it is preferable that the suction control unit 114 controls the operation of the vacuum electro-pneumatic regulator 54 by controlling the suction amount based on the movement speed (rising speed) of the wafer chuck 34 during the Z-axis rising process.

[0071] 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.

[0072] 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.

[0073] The suction step may be started at least before the ring-shaped seal member 48 comes into contact with the head stage 30 in the Z-axis raising step and the internal space S becomes sealed (see reference numeral 500B in FIG. 7). For example, the 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 suction step may also be started simultaneously with the wafer chuck fixing step or the alignment step.

[0074] (Step S18: Wafer chuck height determination process) Next, the Z-axis movement control unit 106 judges whether or not the height position of the wafer chuck 34 has reached the contact position H1. This judgment is repeated until the height position of the wafer chuck 34 reaches the contact position H1, and when the height position of the wafer chuck 34 has reached the contact position H1, the process proceeds to the next step S20.

[0075] A preferred method for detecting the height position of the wafer chuck 34 is to detect the height position of the wafer chuck 34 based on the detection result of a Z-axis encoder provided in the Z-axis moving / rotating unit 72. However, this method is not limited to this method. For example, the height position of the wafer chuck 34 may be obtained from the detection result by detecting the distance (relative distance) between the wafer chuck 34 and the probe card 32 using a distance sensor provided in the wafer chuck 34 or the head stage 30.

[0076] (Step S20: Stopping process) In the above-described wafer chuck height determination step (step S18), when it is determined that the height position of the wafer chuck 34 has reached the contact position H1, the Z-axis movement control unit 106 stops raising the Z-axis movement / rotation unit 72. As a result, each probe 36 of the probe card 32 comes into contact with the electrode pad of each chip on the wafer W with an overdrive amount of 0 (zero).

[0077] (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 T3 in FIG. 9).

[0078] At this time, the chuck suction pressure (pressure applied to suction port 50 by vacuum electropneumatic regulator 54) is at set pressure value P1, so when the fixation of wafer chuck 34 by Z-axis moving / rotating unit 72 is released, wafer chuck 34 leaves Z-axis moving / rotating unit 72 and is attracted toward probe card 32, moving to proper OD position H2 (T3 to T4 in FIG. 9). As a result, the electrode pads of each chip of wafer W to be inspected and each probe 36 of probe card 32 are reliably contacted with a predetermined contact pressure, without being affected by the inclination of wafer W relative to the arrangement surface of the tips of probes 36 and the variation in the tip positions of probes 36.

[0079] In this manner, in this embodiment, the wafer chuck 34 is released from its fixed state while negative pressure is applied to the internal space S. Therefore, at the moment of switching between these processes, the wafer chuck 34 is never 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.

[0080] 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.

[0081] 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.

[0082] (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 T5 to T6 in FIG. 9).

[0083] 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.

[0084] 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.

[0085] Next, the effects of this embodiment will be described.

[0086] According to this embodiment, the operation of moving the wafer chuck 34 to the contact position H1 is performed by the Z-axis moving / rotating unit 72, and the subsequent overdrive is performed by vacuum suction due to the reduced pressure in the internal space S. As a result, the contact operation by the Z-axis moving / rotating unit 72 is limited to the extent of removing the oxide film on the electrode pads, so that good contact can be achieved between the electrode pads on the wafer and the probes without damaging the wafer W.

[0087] Further, according to the present embodiment, the suction step is started before the Z-axis lifting step is performed (more precisely, at least before the ring-shaped seal member 48 comes into contact with the head stage 30 and the internal space S is sealed), so that when the wafer chuck 34 is moved toward the probe card 32 in the Z-axis lifting step, even after 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, 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, so that abnormal contact between the probe card 32 and the wafer W can be prevented, and problems such as damage to the probe card 32 and the wafer W can be prevented. 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 pads. 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.

[0088] In this embodiment, as one example of a preferred embodiment, the suction step is started before the Z-axis lifting step is performed, but the embodiment is not necessarily limited to this embodiment, and for example, the suction step may be started simultaneously with (or after) the Z-axis lifting step as shown in Fig. 10. Also, as shown in Fig. 11, the suction step may be started simultaneously with (or after) the timing at which the Z-axis lifting step is completed (i.e., the timing at which the wafer chuck release step is performed).

[0089] 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.

[0090] In this embodiment, as one example of a preferred embodiment, a mode in which no shutter means is provided on the wafer chuck 34 has been shown, but the present invention is not limited to this mode, and the wafer chuck 34 may be provided with a shutter means. The shutter means provided on the wafer chuck 34 is described in the above-mentioned Patent Document 1, and therefore a description thereof will be omitted here.

[0091] Furthermore, in this embodiment, a negative pressure is applied to the internal space S before the wafer chuck release process is performed. Therefore, when the wafer chuck 34 is released from its position by the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72 in the wafer chuck release process, the unstable state (free state) in which the wafer chuck 34 is not fixed to either side at the moment of switching between these processes is eliminated, and the transfer operation of the wafer chuck 34 can be performed stably.

[0092] In this embodiment, as one example of a preferred embodiment, the chuck adsorption pressure is set to the set pressure value P1 before the wafer chuck release process is performed. However, this is not necessarily limited to this embodiment. For example, as shown in FIG. 10 and FIG. 11, the chuck adsorption pressure may be set to the set pressure value P1 after the wafer chuck release process is performed.

[0093] In this embodiment, the Z-axis moving / rotating unit 72 may move the wafer chuck 34 up and down (in the Z direction) between the contact position and a position below the contact position, thereby making the electrode pads on the wafer W come into contact with the probes 36 multiple times. 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 it is possible to precisely adjust the moving distance and moving speed of the wafer chuck 34. 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 come 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.

[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

[Claim 1] A wafer chuck for holding the wafer; a probe card having a plurality of probes on a surface facing the wafer chuck; a suction means for suction-holding the wafer chuck to the probe card side by reducing the pressure in an internal space between the wafer chuck and the probe card; a relative moving means for moving the wafer chuck and the probe card relatively closer to each other to a contact position where the probes contact the electrode pads of the wafer, using a means other than the suction means; a suction control means for starting a suction operation by the suction means before the internal space is sealed, and for moving the wafer chuck from the contact position to an overdrive position where the probe contacts the electrode pad of the wafer in an overdrive state; The prober comprises:

Images