Probe control device

Abstract

The present invention provides a prober control device that can achieve good contact between the electrode pads on the wafer and the probe without providing a shutter mechanism in the wafer chuck. [Solution] The probe control device controls a suction operation that reduces the pressure in the space between the wafer chuck 34 and the probe card 32 using a suction device 44, and a movement operation that brings the wafer chuck 34 and the probe card 32 closer together using means other than the suction device 44. The probe control device includes a control unit that controls the suction operation so that the gas equivalent to the volume reduction in the space due to the movement operation is sucked in.

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 having a plurality of measurement units and a probe inspection method.

Background Art

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

[0003] After wafer-level inspection, the wafer is attached to a frame and cut into individual chips by a dicing saw. Only the chips that have been confirmed to operate normally among the cut chips are packaged in the next assembly process, and the chips with malfunction are removed from the assembly process. Further, the packaged final product is subjected to a shipping inspection.

[0004] Wafer-level inspection is performed using a prober that contacts probes with the electrode pads of each chip on the wafer. The probes are electrically connected to the terminals of the test head, and a power supply and a test signal are supplied from the test head to each chip via the probes, and the output signal from each chip is detected by the test head to measure whether it operates normally.

[0005] In semiconductor manufacturing processes, wafer size is increasing and further miniaturization (integration) is progressing to reduce manufacturing costs, resulting in a very large number of chips formed on a single wafer. Consequently, the time required to inspect a single wafer with a prober has also increased, and there is a need to improve throughput. Therefore, to improve throughput, multi-probing is being implemented, which uses multiple probes to inspect multiple chips simultaneously. In recent years, the number of chips to be inspected simultaneously has increased even further, and attempts are being made to inspect all chips on a wafer simultaneously. As a result, the tolerance for alignment of the contact between the electrode pads and probes has become smaller, and there is a need to improve the positional accuracy of the prober's movement.

[0006] On the other hand, the simplest way to increase throughput is to increase the number of probers. However, increasing the number of probers increases the footprint of the probers on the manufacturing line. Increasing the number of probers also increases equipment costs. Therefore, there is a need to increase throughput while minimizing increases in footprint and equipment costs.

[0007] Against this backdrop, for example, Patent Document 1 proposes a multi-stage prober equipped with multiple measurement units. In this prober, the alignment device that performs relative positioning between the wafer and the probe card is configured to move between each measurement unit. This allows the alignment device to be shared among the measurement units, thereby saving space and reducing costs.

[0008] Furthermore, the prober described in Patent Document 1 employs a vacuum suction method in which the wafer chuck is held 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 depressurization means, and the wafer chuck is pulled towards the probe card side, thereby performing a contact operation in which the electrode pads of each chip on the wafer come into contact with each probe on the probe card. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2016-032110 [Overview of the project] [Problems that the invention aims to solve]

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

[0011] However, when the wafer chuck is raised by the lifting mechanism of the alignment device, if the internal space formed between the probe card and the wafer chuck is not in communication with the external space (sealed), the air in the internal space will be instantaneously compressed as the wafer chuck rises, generating a strong reaction force. This reaction force may cause the probe card and wafer to come into unintended contact. In this case, abnormal contact between the probe card and the wafer may cause damage to the probe card or wafer. Furthermore, the reaction force due to the compression of the internal space will put a load on the lifting mechanism of the alignment device, affecting the movement speed of the wafer chuck relative to the probe card, which may prevent sufficient removal of the oxide film on the electrode pads.

[0012] To address this problem, the prober described in Patent Document 1 employs a configuration in which a shutter means capable of selectively opening and closing a communication passage connecting the internal space and the external space is provided on the wafer chuck. With this configuration, when the wafer chuck is raised by the lifting mechanism of the alignment device, the communication passage is opened by the shutter means, resulting in a state of communication (non-sealed state) where the internal space is in communication with the external space. This prevents damage to the probe card or wafer due to abnormal contact between the probe card and the wafer. Furthermore, since the wafer chuck can be raised at a desired speed without being affected by the reaction force mentioned above during contact operation, it is possible to obtain a sufficient speed to remove the oxide film on the electrode pad.

[0013] However, while the prober described in Patent Document 1 can prevent the effects of reaction forces caused by compression of the internal space as the wafer chuck rises by using a shutter mechanism provided on the wafer chuck, it has the following problems.

[0014] In other words, attaching the components of the shutter mechanism to the wafer chuck creates a heat dissipation element, which affects the temperature distribution of the wafer chuck. This is especially problematic when inspections are performed in unusual environments such as high or low temperatures, as the wafer chuck is heated or cooled during the inspection, which significantly impacts the temperature distribution of the wafer chuck. Furthermore, this impact on the temperature distribution of the wafer chuck can change the flatness of the wafer chuck's mounting surface (wafer holding surface), resulting in uneven contact pressure between each probe on the probe card and the electrode pads on each chip of the wafer, which reduces the measurement accuracy of wafer-level inspections.

[0015] Furthermore, in configurations where a shutter mechanism is provided on the wafer chuck, the components of the shutter mechanism can disrupt the weight balance of the wafer chuck. As a result, the transfer operation of the wafer chuck from the alignment device to the probe card may become unstable, potentially preventing good contact between the electrode pads on the wafer and the probe.

[0016] The present invention has been made in view of these circumstances, and aims to provide a prober and probe inspection method that can achieve good contact between an electrode pad on a wafer and a probe without providing a shutter mechanism in the wafer chuck. [Means for solving the problem]

[0017] To achieve the above objective, the following invention is provided.

[0018] 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 wafer chuck fixing part for detachably fixing the wafer chuck, a mechanical lifting means for raising and lowering the wafer chuck fixed to the wafer chuck fixing part, a suction means for adsorbing and holding the wafer chuck to the probe card side by reducing the pressure of the internal space, and a suction control means for controlling the suction operation by the suction means, the suction control means for starting the suction operation by the suction means before the internal space becomes sealed.

[0019] In a probe according to a second aspect of the present invention, in the first aspect, the mechanical lifting means moves the wafer chuck toward the probe card so that the probe is in overdrive contact with the electrode pads of the wafer.

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

[0021] The probe inspection method according to the 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 seal member forming an internal space between the wafer chuck and the probe card, a wafer chuck fixing portion for detachably fixing the wafer chuck, mechanical lifting means for lifting and lowering the wafer chuck fixed to the wafer chuck fixing portion, and suction means for sucking and holding the wafer chuck on the probe card side by decompressing the internal space. The method includes a wafer chuck moving step of moving the wafer chuck toward the probe card by the mechanical lifting means, a pre-suction step of starting a suction operation by the suction means before the internal space becomes airtight, and a main suction step of sucking and holding the wafer chuck on the probe card side by decompressing the internal space by the suction means after the wafer chuck moving step is performed.

[0022] The probe inspection method according to the fifth aspect of the present invention is, in the fourth aspect, the wafer chuck moving step is to move the wafer chuck toward the probe card by the mechanical lifting means so that the probes contact the electrode pads of the wafer in an overdrive state.

[0023] The probe inspection method according to the sixth aspect of the present invention is, in the fourth or fifth aspect, the pre-suction step is to set the suction amount by the suction means based on the moving speed of the wafer chuck by the mechanical lifting means.

Advantages of the Invention

[0024] According to the present invention, since the suction operation by the suction means is started before the internal space becomes airtight, good contact can be realized between the electrode pads on the wafer and the probes without providing shutter means on the wafer chuck.

Brief Description of the Drawings

[0025] [Figure 1]External view showing the overall configuration of the prober of this embodiment. [Figure 2] Plan view showing the overall configuration of the prober of this embodiment. [Figure 3] A schematic diagram showing the configuration of the measurement unit in the prober of this embodiment. [Figure 4] Schematic diagram showing the configuration of the measurement section in the measurement unit shown in Figure 3. [Figure 5] Functional block diagram showing the configuration of the control device for the prober of this embodiment. [Figure 6] A flowchart illustrating the contact operation in the prober of this embodiment. [Figure 7] A diagram illustrating the contact operation in the prober of this embodiment. [Figure 8] A diagram illustrating the contact operation in the prober of this embodiment. [Figure 9] Timing chart diagram showing an example of contact operation in the prober of this embodiment. [Modes for carrying out the invention]

[0026] Preferred embodiments of the present invention will be described below with reference to the attached drawings.

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

[0028] As shown in Figures 1 and 2, the prober 10 of this embodiment includes a loader unit 14 for supplying and retrieving wafers W (see Figure 4) to be inspected, and a measurement unit 12 arranged adjacent to the loader unit 14. The measurement unit 12 has a plurality of measurement sections 16, and when wafers W are supplied from the loader unit 14 to each measurement section 16, each measurement section 16 performs an inspection of the electrical characteristics of each chip on the wafer W (wafer-level inspection). The wafers W inspected by each measurement section 16 are then retrieved by the loader unit 14. The prober 10 also includes an operation panel 22, a control device 60 (see Figure 5), etc., which will be described later.

[0029] The loader unit 14 includes a load port 18 on which the wafer cassette 20 is placed, and a transport unit 24 that transports wafers W between each measuring unit 16 of the measuring unit 12 and the wafer cassette 20. The transport unit 24 is equipped 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 includes a transport arm 26 that is configured to extend and retract back and forth by the transport unit drive mechanism. A suction 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 adsorption of the back surface of the wafer W with this suction pad. As a result, the wafer W in the wafer cassette 20 is removed by the transport arm 26 of the transport unit 24 and transported to each measuring unit 16 of the measuring unit 12 while being held on its upper surface. After the inspection is completed, the inspected wafer W is returned to the wafer cassette 20 from each measuring unit 16 via the reverse path.

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

[0031] As shown in Figure 3, the measurement unit 12 has a stacked structure (multi-stage structure) in which multiple measurement sections 16 are stacked in a multi-stage manner, and each measurement section 16 is arranged two-dimensionally along the X and Z directions. In this embodiment, as an example, four measurement sections 16 are stacked in the X direction in three stages in the Z direction.

[0032] The measurement unit 12 includes a housing (not shown) having a grid shape formed by combining multiple frames in a grid pattern. This housing is formed by combining multiple frames extending in the X, Y, and Z directions in a grid pattern, and the components of the measurement section 16 are arranged in each of the spaces formed by these frames.

[0033] Each measurement unit 16 has the same configuration and, as shown in Figure 4, includes a head stage 30, a probe card 32, and a wafer chuck 34. 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).

[0034] The headstage 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 it. The probe card 32 attached and fixed to the headstage 30 is positioned to face the wafer holding surface 34a of the wafer chuck 34. The probe card 32 is replaced depending on the wafer W (device) to be inspected.

[0035] The probe card 32 is equipped with multiple probes 36, such as cantilevers and spring pins, which are arranged to correspond to the positions of the electrode pads on each chip of the wafer W to be tested. 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 the output signals from each chip are detected by the test head to measure whether they are functioning correctly. Note that the connection configuration between the probe card 32 and the test head is not a key part of the present invention, so a detailed explanation is omitted.

[0036] The probe 36 has spring properties and makes contact with the electrode pad with a predetermined contact pressure by raising the contact point from the tip position of the probe 36. Furthermore, when the electrode pad is in an overdrive state during electrical testing, the tip of the probe 36 will sink into the surface of the electrode pad, forming needle marks on the surface of the electrode pad. Overdrive 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, taking into account the inclination between the wafer W and the alignment surface of the tip of the probe 36, and variations in the tip position of the probe 36, in order to ensure reliable contact between the electrode pad and the probe 36. The amount of movement of the wafer W surface further raised from the tip position (contact position) of the probe 36, i.e., the above distance α, is called the overdrive amount.

[0037] The wafer chuck 34 secures 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 multiple suction ports 40 are provided on the wafer holding surface 34a (only one is shown in Figure 4). The suction ports 40 are connected to a suction device (vacuum source) 44, such as a vacuum pump, via a suction passage 42 formed inside the wafer chuck 34. A wafer suction solenoid valve 46 is provided in the suction path connecting the suction device 44 and the suction passage 42. The wafer suction solenoid valve 46 is controlled by a wafer suction solenoid valve control unit 110 (see Figure 5).

[0038] Outside the wafer holding surface 34a of the wafer chuck 34, an elastic ring-shaped sealing member (chuck seal rubber) 48 is provided, formed 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 movement / rotation unit 72, which will be described later, the ring-shaped sealing member 48 comes into contact with the lower surface of the head stage 30, thereby forming an internal space S (see Figure 7) surrounded by the wafer chuck 34, the probe card 32, and the ring-shaped sealing member 48. The ring-shaped sealing member 48 is an example of an annular sealing member of the present invention.

[0039] The headstage 30 is provided with a suction port 50 for reducing the pressure in the internal space S formed between the probe card 32 and the wafer chuck 34. The suction port 50 is connected to a suction device 44 via a suction passage 52 formed inside the headstage 30. A vacuum electro-pneumatic regulator 54 is provided in the suction path connecting the suction device 44 and the suction passage 52. The vacuum electro-pneumatic regulator 54 is a control valve that adjusts the internal pressure (vacuum level) of the internal space S. The vacuum electro-pneumatic regulator 54 is controlled by a suction control unit 114 (see Figure 5), which will be described later. The suction device 44 and the vacuum electro-pneumatic regulator 54 are examples of suction means of the present invention.

[0040] Inside the wafer chuck 34, a heating / cooling mechanism (not shown) is provided as a heating / cooling source so that the electrical characteristics of the wafer W to be inspected can be tested at high temperatures (e.g., up to 150°C) or low temperatures (e.g., down to -40°C). As the heating / cooling mechanism, any known suitable heater / cooler can be used. For example, a double-layer structure consisting of a heating layer of a surface heater and a cooling layer with passages for a cooling fluid, or a single-layer heating / cooling device with a cooling tube embedded in a heat conductor wrapped around a heating element, are all conceivable. Furthermore, instead of electric heating, a system that circulates a thermal fluid may be used, or a Peltier element may be used.

[0041] 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 perform relative alignment between the wafer W held in the wafer chuck 34 and the probe card 32.

[0042] The alignment apparatus 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 and rotates it in the θ direction with the Z-axis as the center of rotation, an X-axis moving table 74 that supports the Z-axis moving / rotating unit 72 and moves in the X-axis direction, and a Y-axis moving table 76 that supports the X-axis moving table 74 and moves in the Y-axis direction.

[0043] The Z-axis movement / rotation unit 72, the X-axis movement table 74, and the Y-axis movement table 76 are each configured to move or rotate the wafer chuck 34 in a predetermined direction by a mechanical drive mechanism including at least a motor. The mechanical drive mechanism is, for example, a ball screw drive mechanism that combines a servo motor and a ball screw. However, it is not limited to a ball screw drive mechanism, and may also be a linear motor drive mechanism, a belt drive mechanism, etc. The Z-axis movement / rotation unit 72, the X-axis movement table 74, and the Y-axis movement table 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 later. In this embodiment, the configuration is specifically as follows.

[0044] The Z-axis movement and rotation 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, servo motor, linear motor, etc.) (see Figure 5) for moving the wafer chuck 34 in the Z-axis direction, and a Z-axis encoder (e.g., a rotary encoder, linear scale, etc.) (not shown) for detecting the distance the wafer chuck 34 moves in the Z-axis direction. The Z-axis drive motor 122 is controlled based on a motor control signal from the Z-axis movement control unit 106 (see Figure 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.

[0045] The Z-axis movement and rotation unit 72 also includes a rotary drive motor 124 (e.g., a stepping motor, servo motor, linear motor, etc.) (see Figure 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 the θ rotation control unit 108 (see Figure 5), which will be described later, and drives the wafer chuck 34 to move to the target position at a desired rotational speed or acceleration. The rotary encoder outputs an encoder signal according to the rotation of the wafer chuck 34.

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

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

[0048] The alignment device 70 is provided for each stage (see Figure 3) and is configured to move between multiple measuring units 16 located on each stage by an alignment device drive mechanism (not shown). That is, the alignment device 70 is shared among multiple (four in this example) measuring units 16 located on the same stage and moves between multiple measuring units 16 located on the same stage. Once the alignment device 70 has moved to each measuring unit 16, it is fixed in a predetermined position by a positioning fixing device (not shown), and moves the wafer chuck 34 in the X, Y, Z, and θ directions to perform relative alignment between the wafer W held in the wafer chuck 34 and the probe card 32. 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 of the wafer W held in the wafer chuck 34 and the probe 36. The alignment device drive mechanism is composed of a mechanical drive mechanism such as a ball screw drive mechanism, a linear motor drive mechanism, or a belt drive mechanism.

[0049] The wafer chuck support surface 72a of the Z-axis moving / rotating section 72, which constitutes the upper surface of the alignment device 70, is provided with an elastic ring-shaped sealing member (Z-axis sealing rubber) 78 formed in an annular shape along its outer circumference. A suction port 80 is provided inside the ring-shaped sealing member 78 of the wafer chuck support surface 72a. The suction port 80 is connected to the suction device 44 via a suction passage 82 formed inside the wafer chuck 34. The suction path connecting the suction device 44 and the suction passage 82 is provided with a chuck fixing solenoid valve 84 and a throttle valve 86, in that 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 Figure 5), which will be described later. The wafer chuck support surface 72a of the Z-axis moving / rotating section 72 is an example of the wafer chuck fixing section 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 section.

[0050] On the outside of the ring-shaped sealing member 78 of the wafer chuck support surface 72a of the Z-axis moving / rotating unit 72, positioning pins 88 are provided to ensure that the relative position of the wafer chuck 34 with respect to the alignment device 70 remains constant. These positioning pins 88 are provided at three equally spaced locations along the circumferential direction centered on the central axis of the wafer chuck 34 (only two are shown in Figure 4). V-blocks 90, which are positioning members, are provided on the lower surface of the wafer chuck 34 at positions corresponding to each positioning pin 88. When the wafer chuck 34 is attracted and fixed by vacuum suction, the horizontal movement (X and Y directions) of the wafer chuck 34 is constrained by engaging the corresponding positioning pins 88 in the V-grooves of each V-block 90, thereby achieving relative positioning between the alignment device 70 and the wafer chuck 34.

[0051] 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 to fix the wafer chuck 34, such as mechanical means.

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

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

[0054] The control unit 60 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and an input / output interface. In the control unit 60, various programs, such as control programs stored in ROM, are loaded into RAM, and the CPU executes the programs loaded into RAM. This realizes the functions of each part of the control unit 60 shown in Figure 5, and various arithmetic and control processes are executed via the input / output interface.

[0055] As shown in Figure 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, etc.

[0056] The overall control unit 100 comprehensively controls each component of 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 the 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 detailed explanations of controls other than the contact operation are omitted as they are not characteristic parts of the present invention.

[0057] The X-axis movement control unit 102 moves the wafer chuck 34 in the X-axis direction by controlling the drive of the X-axis drive motor 118 provided on the X-axis movement table 74, thereby moving the X-axis movement table 74 in the X-axis direction. The Y-axis movement control unit 104 moves the wafer chuck 34 in the Y-axis direction by controlling the drive of the Y-axis drive motor 120 provided on the Y-axis movement table 76, thereby moving the Y-axis movement table 76 in the Y-axis direction. The Z-axis movement control unit 106 moves the wafer chuck 34 in the Z-axis direction by controlling the drive of the Z-axis drive motor 122 provided on the Z-axis movement / rotation unit 72, thereby raising and lowering the Z-axis movement / rotation unit 72. The θ-rotation control unit 108 rotates the wafer chuck 34 in the θ direction by controlling the drive of the rotation drive motor 124 provided on the Z-axis movement / rotation unit 72, thereby rotating the Z-axis movement / rotation unit 72 in the θ direction.

[0058] The wafer adsorption solenoid valve control unit 110 controls the ON / OFF (open / close) of the wafer adsorption solenoid valve 46 to adjust the suction pressure from the suction port 40, and selectively switches between fixing / not fixing the wafer W to the wafer chuck 34.

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

[0060] The suction control unit 114 controls the operation of the vacuum electro-pneumatic regulator 54 to continuously adjust the internal pressure (vacuum level) of the internal space S. Note that the suction control unit 114 is an example of the suction control means of the present invention.

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

[0062] Figure 6 is a flowchart showing the contact operation in the prober 10 of this embodiment. Figures 7 and 8 are diagrams illustrating the contact operation in the prober 10 of this embodiment. Figure 9 is a timing chart diagram showing an example of the contact operation in the prober 10 of this embodiment. Note that the time widths in the timing chart shown in Figure 9 are represented for the sake of simplifying the drawing and do not represent actual time. Also, "Z-axis height" in Figure 9 refers to the height position of the Z-axis moving / rotating part 72 (specifically, the position of the wafer chuck support surface 72a in the Z-axis direction). Also, "chuck height" in Figure 9 refers to the height position of the wafer chuck 34 (specifically, the position of the wafer holding surface 34a in the Z-axis direction).

[0063] (Preliminary actions) This section explains the pre-contact actions.

[0064] First, as a preliminary step to the contact operation, the alignment device 70 is moved to the measurement unit 16 that will be inspected, and then the wafer chuck 34 is handed over to the alignment device 70 while it is positioned and fixed by a positioning and fixing device (not shown). Note that the handover operation of the wafer chuck 34 before the start of the contact operation is not a key part of the present invention, so a detailed explanation is omitted.

[0065] (Step S10: Wafer chuck fixing process) After the wafer chuck 34 is handed over to the alignment device 70, as shown by reference numeral 500A in Figure 7, the chuck fixing solenoid valve control unit 112 turns on (opens) the chuck fixing solenoid valve 84, and fixes the wafer chuck 34 by attraction to the wafer chuck support surface 72a (see Figure 4) of the Z-axis movement / rotation unit 72 (time T1 in Figure 9). At this time, the relative positioning of the alignment device 70 and the wafer chuck 34 is performed by engaging the positioning pin 88 of the Z-axis movement / rotation unit 72 into the V-groove of the V-block 90 of the wafer chuck 34.

[0066] Subsequently, when the wafer W is supplied (loaded) to 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 to the wafer holding surface 34a (see Figure 4) (time T2 in Figure 9).

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

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

[0069] In this embodiment, the suction control unit 114 controls the suction amount based on the movement speed (upward speed) of the wafer chuck 34 in the Z-axis lifting process, which will be described later, when controlling the operation of the vacuum electro-pneumatic regulator 54.

[0070] Specifically, the area of ​​the surface (adsorption surface) surrounded by the ring-shaped sealing member 48 is A [mm²] 2 ] and set the moving speed of the wafer chuck 34 to V z When the movement speed is set to [mm / s], the volume (capacity) V [mm²] of the internal space S formed between the wafer chuck 34 and the probe card 32 decreases per unit time as the wafer chuck 34 moves after the ring-shaped sealing member 48 has come into contact with the head stage 30. 3 Since [ / s] is expressed by the following equation, control is performed so that the suction amount is at least equal to volume V.

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

[0072] The pre-suction process only needs to be started at least before the ring-shaped sealing member 48 comes into contact with the head stage 30 during the Z-axis lifting process described later (see reference numeral 500B in Figure 7). For example, the pre-suction process may be started between the wafer chuck fixing process and the alignment process, or it may be started before the wafer chuck fixing process. Alternatively, the pre-suction process may be started simultaneously with the wafer chuck fixing process or the alignment process.

[0073] (Step S16: Z-axis lifting process) Next, as shown by reference numerals 500B and 500C in Figure 7, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to raise the Z-axis movement and rotation unit 72, thereby moving the wafer chuck 34 toward the probe card 32 (times T4 to T6 in Figure 9).

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

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

[0076] In this embodiment, the pre-suction process is started before the ring-shaped sealing member 48 comes into contact with the head stage 30 during the Z-axis lifting process (see reference numeral 500B in Figure 7). Therefore, even after the ring-shaped sealing member 48 comes into contact with the head stage 30 and the internal space S becomes sealed, the internal space S is not affected by the reaction force due to compression. As a result, abnormal contact between the probe card 32 and the wafer W can be prevented, and the wafer chuck 34 can be stably moved toward the probe card 32 at a sufficient speed to remove the oxide film on the electrode pads.

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

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

[0079] In this embodiment, the pre-suction process and the main suction process are shown to be performed continuously. However, the embodiment is not limited to this, and the pre-suction process may be terminated before the main suction process begins.

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

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

[0082] At this time, the internal pressure of the internal space S is adjusted to the set pressure by the vacuum electro-pneumatic regulator 54. When the wafer chuck 34 is released from the Z-axis movement / rotation unit 72, the wafer chuck 34 detaches from the Z-axis movement / rotation unit 72 and is pulled towards the probe card 32, moving to the appropriate OD position H3 (T8-T9 in Figure 9). As a result, the electrode pads of each chip in the wafer W to be inspected and each probe 36 of the probe card 32 make reliable contact with a predetermined contact pressure, without being affected by the inclination between the wafer W and the arrangement surface of the tips of the probes 36, or by variations in the tip positions of the probes 36.

[0083] In this embodiment, since the wafer chuck 34 is released after the depressurization of the internal space S begins, there is no state in which the wafer chuck 34 is not fixed to either side (free state) at the moment of switching between these processes, and the wafer chuck 34 can be stably transferred.

[0084] Furthermore, in this embodiment, a throttle valve 86 is provided in the suction path connecting the suction passage 82 of the Z-axis movement / rotation unit 72 and the solenoid valve 84 for fixing the chuck. Therefore, even if the wafer chuck 34 is released after the depressurization of the internal space S begins, the negative pressure on the lower side of the wafer chuck 34 (the side of the Z-axis movement / rotation unit 72) is not suddenly lost. As a result, the restraint from below (i.e., the fixing force due to suction from the Z-axis movement / rotation unit 72) does not suddenly disappear while the wafer chuck 34 is being pulled from both the upper and lower sides (i.e., both sides of the Z-axis movement / rotation unit 72 and the probe card 32), thus reducing abnormal vibrations and abnormal contacts associated with the rapid movement of the wafer chuck 34. Consequently, it is possible to suppress the wafer chuck 34 from rapidly detaching from the Z-axis movement / rotation unit 72 when the wafer chuck release process is performed, making it possible to perform the wafer chuck 34 transfer operation more stably.

[0085] In this embodiment, as an example, a configuration is shown in which a throttle valve 86 is provided in the suction path connecting the suction passage 82 of the Z-axis moving / rotating unit 72 and the solenoid valve 84 for fixing the chuck. However, it is sufficient for the throttle valve 86 to be 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 passage 82 of the Z-axis moving / rotating unit 72.

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

[0087] As described above, 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), each probe 36 of the probe card 32 makes contact with the electrode pads of each chip on the wafer W with uniform contact pressure, and the wafer level inspection can be started. Subsequently, power and test signals are supplied from the test head to each chip on the wafer W via each probe 36, and electrical operation tests are performed by detecting the signals output from each chip.

[0088] 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 carried out sequentially.

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

[0090] According to this embodiment, the pre-suction process is started before the ring-shaped sealing member 48 comes into contact with the head stage 30 during the Z-axis lifting process (see reference numeral 500B in Figure 7). Therefore, when the wafer chuck 34 is moved toward the probe card 32, even if the ring-shaped sealing member 48 comes into contact with the head stage 30 and the internal space S becomes sealed, it is not affected by the reaction force due to the compression of the internal space S. As a result, 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 abnormal contact between the probe card 32 and the wafer W can be prevented, and problems such as damage to the probe card 32 or wafer W can be prevented. Furthermore, 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 between the electrode pads on the wafer W and the probe 36 can be achieved without providing a shutter means on the wafer chuck 34.

[0091] Furthermore, in this embodiment, since there is no need to provide a shutter mechanism on the wafer chuck 34, the wafer chuck 34 is not equipped with components of a shutter mechanism that would serve as a heat dissipation element, thus eliminating any influence on the temperature distribution of the wafer chuck 34. In addition, by eliminating the influence on the temperature distribution of the wafer chuck 34, the flatness of the wafer holding surface 34a of the wafer chuck 34 is improved. As a result, the parallelism between the wafer W and the probe card 32 can be increased, enabling high-precision wafer level inspection. Also, since the number of components mounted on the wafer chuck 34 can be reduced, it becomes easier to balance the weight of the wafer chuck 34. As a result, it becomes possible to stably perform contact operations using the vacuum suction method without disrupting the weight balance of the wafer chuck 34.

[0092] Furthermore, in this embodiment, the wafer chuck 34 may be moved up and down (in the Z direction) by the Z-axis movement and rotation unit 72, thereby performing an operation to bring the electrode pads on the wafer W and the probe 36 into contact multiple times in an overdrive state. Since the Z-axis movement and rotation unit 72 in this embodiment is composed of a mechanical drive mechanism including at least a motor (Z-axis drive motor 122), it is possible to precisely adjust the movement distance and movement speed of the wafer chuck 34. In addition, the Z-axis movement and rotation unit 72 can move the wafer chuck 34 at a sufficiently faster movement speed compared to when the wafer chuck 34 is moved toward the probe card 32 by reducing the pressure of the internal space S. Therefore, when bringing the electrode pads on the wafer W into contact with the probe 36, it is possible to remove the oxide film (insulator) on the electrode pads by contact with the probe 36, and good contact can be achieved between the electrode pads on the wafer W and the probe 36 without damaging the wafer W.

[0093] Furthermore, in this embodiment, the wafer chuck 34 is released from the suction port 80 (see Figure 4) of the Z-axis moving / rotating unit 72 at a later timing (second timing; time T8 in Figure 9) than the timing (first timing; time T7 in Figure 9) when the main suction process (depressurization of the internal space S) is started. As a result, there is no unstable state (free state) in which the wafer chuck 34 is not fixed to either side at the moment of switching between these processes, and the wafer chuck 34 can be stably transferred.

[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 rapidly detaching from the Z-axis moving / rotating unit 72 when the chuck fixing solenoid valve 84 is turned OFF (open to the atmosphere), making it possible to perform the wafer chuck 34 transfer operation more stably.

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

[0096] 10…Probe, 12…Measurement unit, 14…Loader section, 16…Measurement section, 18…Load port, 20…Wafer cassette, 22…Operation panel, 24…Transportation unit, 26…Transportation 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 adsorption, 48…Ring-shaped sealing member, 50…Suction port, 54…Vacuum electro-pneumatic regulator, 56…Communication passage, 60…Control device, 70…Alignment device, 72…Z-axis movement / rotation section, 72a…Wafer chuck support surface, 74…X-axis movement table, 76 ...Y-axis moving table, 78...Ring-shaped sealing member, 78...Ring-shaped sealing member, 80...Suction port, 82...Suction passage, 84...Solenoid valve for chuck fixing, 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...Solenoid valve control unit for wafer adsorption, 112...Solenoid valve control unit for chuck fixing, 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 prober control device that controls a suction operation to reduce the pressure in the space between a wafer chuck and a probe card using a suction means, and a movement operation to bring the wafer chuck and the probe card closer together using means other than the suction means, The system includes a control unit that controls the suction operation so that the gas equivalent to the volume reduction in the space due to the movement operation is sucked in. Control device for probers.

2. The control unit sets the amount of suction by the suction means based on the relative movement speed between the wafer chuck and the probe card. Control device for probers.

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