Prober and probe inspection method

Abstract

To provide a prober capable of realizing good contact between the electrode pad on a wafer and a probe, without damaging the wafer, and to provide a probe inspection method.SOLUTION: In a prober 10 employing a vacuum suction system for holding a wafer chuck 34 on the probe card 32 side, after the wafer chuck 34 is moved toward the probe card 32 to the contact position by a Z-axis movement / rotation part 72, the wafer chuck 34 is moved to a right overdrive position by pressure reduction of the internal space achieved by a vacuum electro-pneumatic regulator 54.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a prober and a probe inspection method for inspecting the 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 equipped with a plurality of measurement units. [Background technology]

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

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

[0004] Wafer-level testing is performed using a prober that contacts the electrode pads of each chip on the wafer with probes. The probes are electrically connected to terminals of a test head, which supplies power and test signals to each chip via the probes, and also detects output signals from each chip to determine whether they are functioning properly.

[0005] In the semiconductor manufacturing process, wafers are becoming larger and more miniaturized (integrated) to reduce manufacturing costs, resulting in a significantly larger number of chips being formed on a single wafer. Consequently, the time required to test a single wafer using a prober is also increasing, necessitating a need for improved throughput. To address this issue, multi-probing, which uses multiple probes to simultaneously test multiple chips, is being adopted to improve throughput. In recent years, the number of chips being tested simultaneously has been steadily increasing, and efforts are being made to simultaneously test all chips on a wafer. As a result, the tolerance for alignment between electrode pads and probes is becoming smaller, necessitating improved positional accuracy in prober movement.

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

[0007] Against 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 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 decompression means, and the wafer chuck is pulled toward the probe card, thereby performing a contact operation in which each probe on the probe card contacts the electrode pads of each chip on the wafer. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-032110 Summary of the Invention [Problem to be solved by the invention]

[0010] In the prober described in Patent Document 1, before the internal space formed between the wafer chuck and the probe card is depressurized, the wafer chuck is raised toward the probe card by the lifting mechanism of the alignment device, and each probe of the probe card is brought into contact with the electrode pad 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 decompressed, which may damage the wafer.

[0012] The present invention has been made in view of the above circumstances, and aims to provide a prober and a probe inspection method that can achieve good contact between electrode pads on a wafer and 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 for forming an internal space between the wafer chuck and the probe card, a mechanical lifting means having a wafer chuck fixing portion for detachably fixing the wafer chuck and for raising and lowering the wafer chuck fixed to the wafer chuck fixing portion, a suction means for adsorbing and holding the wafer chuck to 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, which moves 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, which moves 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 prober according to a third aspect of the present invention is the prober of 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 for 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 portion for detachably 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 to the probe card side by reducing the pressure of 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, the wafer chuck being moved to a contact position where the probes contact the electrode pads of the wafer; and a suction step for reducing the pressure of the internal space by the suction means, the wafer chuck being moved 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 fourth aspect, wherein the suction step is started before the internal space is sealed.

[0019] A probe inspection method according to a sixth aspect of the present invention is 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. [Effects 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 explanation 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; [Figure 2] FIG. 1 is a plan view showing the overall configuration of a prober according to an embodiment of the present invention; [Figure 3]1 is a schematic diagram showing the configuration of a measurement unit in a prober according to an embodiment of the present invention; [Figure 4] FIG. 4 is a schematic diagram showing the configuration of a measurement section in the measurement unit shown in FIG. 3. [Figure 5] FIG. 1 is a functional block diagram showing the configuration of a control device of a prober according to an embodiment of the present invention; [Figure 6] 1 is a flowchart showing a contact operation in the prober of the present embodiment. [Figure 7] FIG. 10 is a diagram for explaining a contact operation in the prober of the present embodiment. [Figure 8] FIG. 10 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. 10 is a timing chart showing another example of the contact operation in the prober of the present embodiment. [Figure 11] FIG. 10 is a timing chart showing another example of the contact operation in the prober of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present invention will now 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 this embodiment.

[0024] 1 and 2, the prober 10 of this embodiment includes a loader section 14 that supplies and retrieves 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 retrieved by the loader section 14. The prober 10 also includes an operation panel 22, a control device 60 (see FIG. 5), which will be described later, and the like.

[0025] The loader section 14 includes a load port 18 on which a wafer cassette 20 is placed and a transfer unit 24 that transfers wafers W between the wafer cassette 20 and each measurement section 16 of the measurement unit 12. The transfer unit 24 is equipped with a transfer 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 transfer unit 24 also includes a transfer arm 26 that is configured to be extendable and retractable back and forth by the transfer unit drive mechanism. A suction pad (not shown) is provided on the upper surface of the transfer arm 26, and the transfer arm 26 holds the wafer W by vacuum suction of the backside of the wafer W using this suction pad. As a result, the wafer W in the wafer cassette 20 is removed by the transfer arm 26 of the transfer unit 24 and transferred to each measurement section 16 of the measurement unit 12 while held on its upper surface. After inspection, the inspected wafer W is returned from each measurement section 16 to the wafer cassette 20 via the reverse route.

[0026] 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.

[0027] 3, the measurement unit 12 has a stacked structure (multi-tier structure) in which a plurality of measurement parts 16 are stacked in multiple tiers, and the measurement parts 16 are arranged two-dimensionally along the X and Z directions. In this embodiment, as an example, four measurement parts 16 are stacked in the X direction, and three tiers are stacked in the Z direction.

[0028] The measurement unit 12 includes a housing (not shown) having a lattice shape formed by combining multiple frames in a lattice pattern. This housing is formed by combining multiple frames extending in the X, Y, and Z directions in a lattice pattern, and components of the measurement section 16 are arranged 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 also provided with a test head (not shown). The test head is supported above the head stage 30 by a test head holder (not shown).

[0030] The head stage 30 is supported by a frame member (not shown) that constitutes 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 disposed 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, while output signals from each chip are detected by the test head to measure whether they are operating normally. Note that the connection configuration between the probe card 32 and the test head is not a main part of the present invention, so a detailed description thereof will be omitted.

[0032] The probes 36 have spring characteristics, and by raising the contact points from the tip positions of the probes 36, they contact the electrode pads with a predetermined contact pressure. Furthermore, when the probes 36 contact the electrode pads in an overdrive state during electrical testing, the tips of the probes 36 sink into the surfaces of the electrode pads, leaving needle marks on the surfaces of the electrode pads. Note that overdrive refers to a state in which the electrode pads, i.e., the surface of the wafer W, are raised by a distance α to a position higher than the tip positions of the probes 36 to ensure reliable contact between the electrode pads and the probes 36, taking into consideration the inclination of the wafer W and the arrangement surface of the tips of the probes 36 and variations in the tip positions of the probes 36. The distance α, which is the amount of movement by which the surface of the wafer W is further raised from the tip position (contact position) of the probes 36, 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 the wafer holding surface 34a is provided with a plurality of suction ports 40 (only one of which 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 in 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 a Z-axis moving / rotating unit 72 (described later), the ring-shaped seal member 48 comes into contact with the underside 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 ), which will be described later. The suction device 44 and the vacuum electro-pneumatic regulator 54 are examples of the suction means of the present invention.

[0036] A heating / cooling mechanism (not shown) is provided inside the wafer chuck 34 as a heating / cooling source so that the electrical characteristics of the wafer W to be inspected can be inspected at a high temperature (e.g., up to 150°C) or a low temperature (e.g., down to -40°C). Any suitable known heater / cooler can be used as the heating / cooling mechanism, and various types are conceivable, including a double-layer structure consisting of a heating layer of a surface heater and a cooling layer with a cooling fluid passage, or a single-layer heating / cooling device in which a cooling pipe wrapped around a heater is embedded in a thermal conductor. Instead of electrical heating, a device that circulates a thermal fluid or a Peltier element may also be used.

[0037] The wafer chuck 34 is detachably supported and fixed to an alignment device 70, which will be described later. The alignment device 70 moves the wafer chuck 34 in the X, Y, Z, and θ directions to align the wafer W held by the wafer chuck 34 with the probe card 32 relative to one another.

[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 around 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 using a mechanical drive mechanism including at least a motor. The mechanical drive mechanism may be, for example, a ball screw drive mechanism that combines a servo motor and a ball screw. The mechanism is not limited to a ball screw drive mechanism, and may also be a linear motor drive mechanism or a belt drive mechanism. The Z-axis moving / rotating unit 72, the X-axis moving stage 74, and the Y-axis moving stage 76 are configured so that the movement distance, movement direction, movement speed, and acceleration of the wafer chuck 34 can be changed by the respective control units described below. This embodiment specifically has the following configuration.

[0040] The Z-axis moving / rotating unit 72 is an example of a 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 or 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. The Z-axis encoder outputs an encoder signal in accordance with the movement of the wafer chuck 34.

[0041] The Z-axis moving / rotating unit 72 also 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 rotational speed or acceleration. The rotary encoder also 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, servo motor, 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 or 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. The X-axis encoder also 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, servo motor, 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 or 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. The Y-axis encoder also outputs an encoder signal in accordance with the movement of the wafer chuck 34.

[0044] An 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 among the multiple (four in this example) measurement units 16 arranged on the same stage and moves between the multiple measurement units 16 arranged on the same stage. After moving to each measurement unit 16, the alignment device 70 is fixed in a predetermined position by a positioning and fixing device (not shown). The alignment device 70 then moves the wafer chuck 34 in the X, Y, Z, and θ directions to align the wafer W held on the wafer chuck 34 with the probe card 32 relative to each other. Although not shown, the alignment device 70 is equipped with a needle position detection camera and a wafer alignment camera to detect the relative positional relationship between the electrode pads of each chip on the wafer W held on the wafer chuck 34 and the probes 36. The alignment device drive mechanism is configured with a mechanical drive mechanism such as a ball screw drive mechanism, a linear motor drive mechanism, or a belt drive mechanism.

[0045] A wafer chuck support surface 72a of the Z-axis moving / rotating unit 72, which constitutes the upper surface of the alignment device 70, is provided with an elastic ring-shaped seal member (Z-axis seal rubber) 78 formed in a ring shape along the outer periphery. A suction port 80 is provided inside the ring-shaped seal member 78 on 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. The suction path connecting the suction device 44 and the suction path 82 is provided with, in order from the suction device 44 side, a chuck fixing solenoid valve 84 and a throttle valve 86. 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 unit 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 unit 72 so that the relative position of the wafer chuck 34 with respect to the alignment device 70 is always constant. These positioning pins 88 are provided at three locations equally spaced circumferentially around the central axis of the wafer chuck 34 (only two are shown in FIG. 4). V-blocks 90, which serve as positioning members, are provided on the underside of the wafer chuck 34 at positions corresponding to the positioning pins 88. When the wafer chuck 34 is vacuum-sucked and fixed, the corresponding positioning pins 88 are engaged with the V-grooves of the V-blocks 90, thereby restricting movement of the wafer chuck 34 in the horizontal directions (X and Y directions), 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 suction, but any fixing means other than vacuum suction may be used as long as it is capable of fixing the wafer chuck 34, and for example, mechanical means may be used to fix the wafer chuck 34.

[0048] FIG. 5 is a functional block diagram showing the configuration of the control device 60 of the prober 10 of this 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 on 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 controls movement of the alignment device 70 between each measurement unit 16, and controls 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 an 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 a 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 an elevation control means of the present invention, and controls the drive of a Z-axis drive motor 122 provided on the Z-axis moving / rotating unit 72 to elevate the Z-axis moving / rotating 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 on the Z-axis moving / rotating unit 72 to rotate the Z-axis moving / 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 fixing and not fixing 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 switch between fixing and not fixing 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 continuously 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, the contact operation (one example of a probe inspection method) of 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 flowchart 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 unit 16 where the inspection will be performed, and then the wafer chuck 34 is positioned and fixed by a positioning and fixing device (not shown) and then transferred to the alignment device 70. 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 state) the chuck fixing solenoid valve 84 to attract 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 on (opens) the wafer adsorption solenoid valve 46, 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 images captured by the needle position detection camera and the wafer alignment camera, to perform relative alignment between the wafer W held on 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 via 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 a pressure value of 0 toward a set pressure value P1. Note that the timing at which the set pressure value P1 is reached is preferably at least before or simultaneously with the timing at which the wafer chuck release process described below starts (time T3 in FIG. 9). This allows for stable transfer of the wafer chuck 34 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 the appropriate overdrive amount (appropriate OD position H2) of the probe card 32 when a wafer chuck release step described later is performed in a state where 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 electropneumatic 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 determined empirically or experimentally, or may be determined from a design value. For example, the set pressure value P1 can be determined from the reaction force (the reaction force when the probes 36 are crushed) received from the probes 36 when the wafer chuck 34 is raised 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 negative pressure to be applied to the internal space S can be determined 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 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) 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 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] During the Z-axis lifting step, as the wafer chuck 34 rises, 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] In this embodiment, when the wafer chuck 34 is moved toward the probe card 32 in the Z-axis lifting step, the suction step, which is 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 moving speed sufficient to remove the oxide film on the electrode pads.

[0070] Furthermore, in this embodiment, when the Z-axis raising process is performed, the suction control unit 114 preferably controls the operation of the vacuum electropneumatic regulator 54 by controlling the amount of suction based on the movement speed (rising speed) of the wafer chuck 34 during the Z-axis raising process.

[0071] Specifically, the area of ​​the surface (attraction 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], after the ring-shaped seal member 48 comes into contact with the head stage 30, the volume (volume) V [mm 3 / s] is expressed by the following equation, so the suction volume is controlled to be at least equal to the 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, gas corresponding to the decrease in volume (capacity) of the internal space S due to the movement of the wafer chuck 34 is sucked in, so no reaction force is generated due to compression of the internal space S.

[0073] The suction step only needs to be started before at least 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 is 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 before the wafer chuck fixing step. Furthermore, the suction step may 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 determines whether the height position of the wafer chuck 34 has reached the contact position H1. This determination is repeated until the height position of the wafer chuck 34 reaches the contact position H1, and if 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 results of a Z-axis encoder provided in the Z-axis moving / rotating unit 72. However, this method is not limitative, and for example, the distance (relative distance) between the wafer chuck 34 and the probe card 32 may be detected by a distance sensor provided in the wafer chuck 34 or the head stage 30, and the height position of the wafer chuck 34 may be obtained from the detection results.

[0076] (Step S20: Stopping process) In the wafer chuck height determination step (step S18) described above, 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 (the pressure applied to the suction port 50 by the vacuum electropneumatic regulator 54) is at the set pressure value P1, so when the wafer chuck 34 is released from the Z-axis moving / rotating unit 72, the wafer chuck 34 separates from the Z-axis moving / rotating unit 72, is attracted toward the probe card 32, and moves to the proper OD position H2 (T3 to T4 in FIG. 9). As a result, the electrode pads of each chip on the wafer W to be inspected and each probe 36 on the probe card 32 are reliably brought into contact with each other at a predetermined contact pressure, regardless of the inclination of the wafer W relative to the arrangement surface of the tips of the probes 36 and the variations in the positions of the tips of the probes 36.

[0079] In this manner, in this embodiment, the wafer chuck 34 is released from its fixed position while a negative pressure is applied to the internal space S, so that 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.

[0080] Furthermore, in this embodiment, 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. This prevents a sudden loss of negative pressure below the wafer chuck 34 (the Z-axis moving / rotating unit 72 side) even when the wafer chuck 34 is released after the internal space S has been depressurized. Therefore, even when the wafer chuck 34 is being pulled from both the top and bottom (i.e., from both the Z-axis moving / rotating unit 72 and the probe card 32), the constraint from below (i.e., the fixing force due to suction from the Z-axis moving / rotating unit 72) is not suddenly lost. This reduces abnormal vibrations and abnormal contacts that may occur due to sudden movement of the wafer chuck 34. Therefore, the wafer chuck 34 is prevented from suddenly separating from the Z-axis moving / rotating unit 72 when the wafer chuck release step is performed, thereby enabling a more stable transfer operation of the wafer chuck 34.

[0081] In this embodiment, as an example, a configuration has been shown in which the 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, but 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, and 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 movement / rotation 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. Thereafter, 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 signals output from each chip.

[0084] After the wafer chuck 34 is transferred from the alignment device 70 (Z-axis movement / rotation unit 72) to the head stage 30 (probe card 32 side), the alignment device 70 moves to another measurement unit 16, where contact operations are performed in the same 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] Furthermore, according to this embodiment, the suction process is initiated before the Z-axis lifting process (more precisely, at least before the ring-shaped seal member 48 contacts the head stage 30 and seals the internal space S). Therefore, when the wafer chuck 34 is moved toward the probe card 32 during the Z-axis lifting process, even after the ring-shaped seal member 48 contacts the head stage 30 and seals the internal space S, the wafer chuck 34 is not affected by a reaction force due to compression of the internal space S. Therefore, no excessive reaction force (a reaction force attempting to return the wafer chuck 34 to its original position) is generated on the wafer chuck 34, preventing abnormal contact between the probe card 32 and the wafer W and preventing damage to the probe card 32 or the wafer W. Furthermore, the wafer chuck 34 can be moved toward the probe card 32 stably, efficiently, and accurately at a sufficient moving speed to remove oxide films on the electrode pads. Therefore, good contact between the electrode pads on the wafer W and the probes 36 can be achieved without providing a shutter mechanism on the wafer chuck 34.

[0088] In this embodiment, as an example of a preferred mode, the suction step is started before the Z-axis lifting step is performed, but the present invention is not necessarily limited to this mode, 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] Furthermore, in this embodiment, there is no need to provide a shutter means on the wafer chuck 34, and therefore the wafer chuck 34 does not need to be provided with components of the shutter means that act as heat dissipation elements, thereby eliminating any effect on the temperature distribution of the wafer chuck 34. Furthermore, the elimination of any effect 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 for a higher degree of parallelism between the wafer W and the probe card 32, enabling highly accurate wafer-level inspection. Furthermore, since the number of components mounted on the wafer chuck 34 can be reduced, it is easier to achieve a weight balance for the wafer chuck 34. As a result, contact operations using the vacuum suction method can be stably performed without disrupting the weight balance of the wafer chuck 34.

[0090] In this embodiment, as an example of a preferred embodiment, a mode in which a shutter means is not provided on the wafer chuck 34 has been shown, but the present invention is not necessarily limited to this mode, and a shutter means may be provided on the wafer chuck 34. 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 fixation 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 an example of a preferred embodiment, the chuck suction pressure is set to the set pressure value P1 before the wafer chuck release step is performed. However, this is not necessarily limited to this embodiment. For example, as shown in FIGS. 10 and 11, the chuck suction pressure may be set to the set pressure value P1 after the wafer chuck release step 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 allowing the probes 36 to contact the electrode pads on the wafer W multiple times. The Z-axis moving / rotating unit 72 in this embodiment is configured with a mechanical drive mechanism including at least a motor (Z-axis drive motor 122), making it possible to precisely adjust the movement distance and movement speed of the wafer chuck 34. Furthermore, the Z-axis moving / rotating unit 72 can move the wafer chuck 34 at a movement speed that is sufficiently faster than when the wafer chuck 34 is moved toward the probe card 32 by depressurizing 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 contact with the probes 36, thereby achieving good contact 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 unit 72. This prevents the wafer chuck 34 from suddenly detaching from the Z-axis moving / rotating unit 72 when the chuck fixing solenoid valve 84 is turned OFF (when open to the atmosphere), making it possible to perform the transfer operation of the wafer chuck 34 more stably.

[0095] The prober and probe inspection method according to the present invention have been described in detail above, but 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...measuring unit, 14...loader section, 16...measuring section, 18...load port, 20...wafer cassette, 22...operation panel, 24...transport unit, 26...transport 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...wafer suction solenoid valve, 48...ring-shaped seal member, 50...suction port, 54...vacuum electro-pneumatic regulator, 56...communicating 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 sealing member, 78...ring-shaped sealing 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 drive motor, 120...Y-axis drive motor, 122...Z-axis drive motor, 124...rotation drive motor, W...wafer, S...internal space

Claims

1. A wafer chuck for holding the wafer; a probe card having a plurality of probes on a surface facing the wafer chuck; a mechanical lifting means for lifting and lowering 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 lift control means for controlling a lift operation by the mechanical lift means, the lift control means lifting and moving the wafer chuck to a contact position where the probes contact the electrode pads of the wafer; a suction control means for controlling a suction operation by the suction means, the suction control means 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; Equipped with The suction control means starts a suction operation by the suction means before the internal space is sealed. Prover.

2. 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.

2. The prober of claim 1.

3. A wafer chuck for holding the wafer; a probe card having a plurality of probes on a surface facing the wafer chuck; a mechanical lifting means for lifting and lowering 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 probe inspection method in a prober comprising: a wafer chuck moving step of moving the wafer chuck toward the probe card by the mechanical lifting means, the wafer chuck being lifted and moved to a contact position where the probes contact the electrode pads of the wafer; a step of reducing the pressure of the internal space by the suction means, the suction step being for 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; Equipped with The suction step is started before the internal space is sealed. Probe testing method.

4. the suction step sets a suction amount by the suction means based on a moving speed of the wafer chuck by the mechanical lifting means; The probe inspection method according to claim 3 .

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