JP2022075881A - Prover and probe inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a prover and a probe inspection method capable of achieving good contact between an electrode pad on a wafer and a probe without providing shutter means on a wafer chuck.

SOLUTION: In a prober 10 that employs a vacuum suction method that holds a wafer chuck 34 on the probe card 32 side, and suction control means that initiates a suction operation of an internal space between the wafer chuck 34 and the probe card 32 by a vacuum electropneumatic regulator 54 before the internal space is sealed.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2022,JPO&INPIT

Description

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

The semiconductor manufacturing process has a large number of processes, and various inspections are performed in various manufacturing processes in order to guarantee quality and improve yield. For example, when a plurality of chips of a semiconductor device are formed on a semiconductor wafer, the electrode pads of the semiconductor device of each chip are connected to a test head, a power supply and a test signal are supplied from the test head, and the semiconductor device is output. Wafer level inspection is performed by measuring the signal with a test head and electrically inspecting whether it operates normally.

After wafer level inspection, the wafer is affixed to the frame and cut into individual chips with a die. For each cut chip, only the chips confirmed to operate normally are packaged in the next assembly process, and the malfunctioning chips are excluded from the assembly process. In addition, the packaged final product is inspected for shipment.

Wafer level inspection is performed using a prober that contacts the probe with the electrode pads of each chip on the wafer. The probe is electrically connected to the terminal of the test head, and the test head supplies power and test signals to each chip via the probe, and the test head detects the output signal from each chip to see if it operates normally. To measure.

In the semiconductor manufacturing process, wafers are being made larger and further miniaturized (integrated) in order to reduce manufacturing costs, and the number of chips formed on one wafer is extremely large. ing. Along with this, the time required for inspecting one wafer with a prober has become longer, and improvement in throughput is required. Therefore, in order to improve the throughput, multiprobing is performed in which a large number of probes are provided so that a plurality of chips can be inspected at the same time. In recent years, the number of chips to be inspected at the same time has been increasing more and more, and attempts have been made to inspect all the chips on the wafer at the same time. Therefore, the tolerance of alignment for contacting the electrode pad and the probe is small, and it is required to improve the positional accuracy of movement in the prober.

On the other hand, the simplest way to increase the throughput is to increase the number of probers, but increasing the number of probers causes a problem that the installation area of the probers in the production line also increases. In addition, if the number of probers is increased, the equipment cost will increase accordingly. Therefore, it is required to increase the throughput by suppressing the increase in the installation area and the increase in the equipment cost.

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

Further, in the prober described in Patent Document 1, a vacuum suction method for holding the wafer chuck on the probe card side is adopted. In this vacuum suction method, the internal space (sealed space) formed between the wafer chuck and the probe card is depressurized by a decompression means, and the wafer chuck is attracted to the probe card side, so that the wafer is attached to each probe of the probe card. A contact operation is performed in which the electrode pads of each chip are brought into contact with each other.

Japanese Unexamined Patent Publication No. 2016-032110

By the way, in the prober described in Patent Document 1, decompression of the internal space formed between the wafer chuck and the probe card is started in order to remove the oxide film formed on the electrode pad of each chip of the wafer. The wafer chuck is raised toward the probe card by the elevating mechanism of the alignment device, and each probe of the probe card is brought into contact with the electrode pad of each chip of the wafer at a predetermined pressure.

However, when the wafer chuck is raised by the elevating mechanism of the alignment device, if the internal space formed between the probe card and the wafer chuck is in a non-communication state (sealed state) in which it does not communicate with the external space, the wafer chuck is used. As the temperature rises, the air in the internal space is momentarily compressed to generate a strong reaction force, which may cause the probe card and the wafer to come into unintended contact with each other. In this case, there is a possibility that the probe card or the wafer may be damaged due to abnormal contact between the probe card and the wafer. In addition, the reaction force due to the compression of the internal space becomes a load on the elevating mechanism of the alignment device, which affects the moving speed of the wafer chuck with respect to the probe card, and there is a possibility that the oxide film on the electrode pad cannot be sufficiently removed. ..

In response to this problem, the prober described in Patent Document 1 employs a configuration in which the wafer chuck is provided with a shutter means capable of selectively opening and closing a communication passage communicating between an internal space and an external space. According to this configuration, when the wafer chuck is raised by the elevating mechanism of the alignment device, the internal space is in a communication state (non-sealed state) in which the internal space is communicated with the external space by opening the communication path by the shutter means. It is possible to prevent the probe card and the wafer from being damaged due to abnormal contact between the probe card and the wafer. Further, since the wafer chuck can be raised at a desired moving speed without being affected by the reaction force described above during the contact operation, it is possible to obtain a sufficient moving speed for removing the oxide film on the electrode pad. It will be possible.

However, in the prober described in Patent Document 1, although the shutter means provided on the wafer chuck can prevent the influence of the reaction force caused by the compression of the internal space due to the ascent of the wafer chuck, the following problems can be prevented. There is.

That is, by attaching the component component of the shutter means to the wafer chuck, there is a problem that the component component of the shutter means becomes a heat dissipation element and affects the temperature distribution of the wafer chuck. Especially when the inspection is performed in an unusual environment such as high temperature or low temperature, the wafer chuck is inspected in a heated or cooled state, but in that case, the influence on the temperature distribution of the wafer chuck is large. .. In addition, the flatness of the mounting surface (wafer holding surface) of the wafer chuck may change due to the influence on the temperature distribution of the wafer chuck, and the contact pressure between each probe of the probe card and the electrode pad of each chip of the wafer Becomes non-uniform, which causes a decrease in the measurement accuracy of the wafer level inspection.

Further, in the case of a configuration in which the shutter means is provided on the wafer chuck, the weight balance of the wafer chuck may be disturbed by the components of the shutter means. Therefore, the transfer operation of the wafer chuck from the alignment device to the probe card side becomes unstable, and there is a possibility that good contact cannot be realized between the electrode pad on the wafer and the probe.

The present invention has been made in view of such circumstances, and a prober and probe inspection capable of achieving good contact between an electrode pad on a wafer and a probe without providing a shutter means on the wafer chuck. The purpose is to provide a method.

The following inventions are provided in order to achieve the above object.

The prober according to the first aspect of the present invention has a wafer chuck for holding a wafer, a probe card having a plurality of probes on a surface facing the wafer chuck, and an annular shape forming an internal space between the wafer chuck and the probe card. The wafer chuck is provided with a seal member and a wafer chuck fixing portion for detachably fixing the wafer chuck, a mechanical lifting means for raising and lowering the wafer chuck fixed to the wafer chuck fixing portion, and a wafer chuck by reducing the internal space. It is provided with a suction means for sucking and holding on the probe card side, and a suction control means for controlling the suction operation by the suction means, which starts the suction operation by the suction means before the internal space is sealed. ..

According to the second aspect of the present invention, in the first aspect, the mechanical elevating means moves the wafer chuck toward the probe card so that the probe is in contact with the electrode pad of the wafer in an overdrive state.

In the prober according to the third aspect of the present invention, in the first aspect or the second aspect, the suction control means sets the suction amount by the suction means based on the moving speed of the wafer chuck by the mechanical elevating means.

In the probe inspection method according to the fourth aspect of the present invention, an internal space is formed between the wafer chuck holding the wafer, the probe card having a plurality of probes on the surface facing the wafer chuck, and the wafer chuck and the probe card. An annular sealing member, a wafer chuck fixing portion for detachably fixing the wafer chuck, a mechanical lifting means for raising and lowering the wafer chuck fixed to the wafer chuck fixing portion, and a wafer by reducing the pressure in the internal space. This is a probe inspection method in a prober equipped with a suction means for sucking and holding the chuck on the probe card side, a wafer chuck moving step in which the wafer chuck is moved toward the probe card by a mechanical elevating means, and an internal space is sealed. After the pre-suction step of starting the suction operation by the suction means and the wafer chuck moving step, the main suction step of sucking and holding the wafer chuck to the probe card side by depressurizing the internal space by the suction means. And.

In the fourth aspect of the probe inspection method according to the fifth aspect of the present invention, in the wafer chuck moving step, the wafer chuck is probed by mechanical elevating means so that the probe is brought into contact with the electrode pad of the wafer in an overdrive state. Move towards the card.

In the probe inspection method according to the sixth aspect of the present invention, in the fourth or fifth aspect, the pre-suction step sets the suction amount by the suction means based on the moving speed of the wafer chuck by the mechanical elevating means.

According to the present invention, since the suction operation by the suction means is started before the internal space is sealed, good contact is made between the electrode pad and the probe on the wafer without providing the shutter means on the wafer chuck. It can be realized.

External view showing the overall configuration of the prober of this embodiment A plan view showing the overall configuration of the prober of this embodiment. Schematic diagram showing the configuration of the measurement unit in the prober of this embodiment. Schematic diagram showing the configuration of the measurement unit in the measurement unit shown in FIG. A functional block diagram showing the configuration of the prober control device of this embodiment. A flowchart showing the contact operation in the prober of this embodiment. The figure for demonstrating the contact operation in the prober of this embodiment. The figure for demonstrating the contact operation in the prober of this embodiment. Timing chart diagram showing an example of contact operation in the prober of this embodiment

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

1 and 2 are an external view and a plan view showing the overall configuration of the prober 10 of the present embodiment.

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

The loader unit 14 has a load port 18 on which the wafer cassette 20 is placed, and a transfer unit 24 for transporting the wafer W between each measurement unit 16 of the measurement unit 12 and the wafer cassette 20. The transport unit 24 includes a transport unit drive mechanism (not shown), is configured to be movable in the X and Z directions, and is configured to be rotatable in the θ direction (around the Z direction). Further, the transport unit 24 includes a transport arm 26 configured to be stretchable back and forth by the transport unit drive mechanism. A suction pad (not shown) is provided on the upper surface of the transfer arm 26, and the transfer arm 26 vacuum-sucks the back surface of the wafer W with the suction pad to hold the wafer W. As a result, the wafer W in the wafer cassette 20 is taken out by the transfer arm 26 of the transfer unit 24 and transferred to each measurement unit 16 of the measurement unit 12 while being held on the upper surface thereof. Further, the inspected wafer W that has been inspected is returned from each measuring unit 16 to the wafer cassette 20 by the reverse route.

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

As shown in FIG. 3, the measuring unit 12 has a laminated structure (multi-stage structure) in which a plurality of measuring units 16 are laminated in a multi-stage manner, and each measuring unit 16 has 2 along the X direction and the Z direction. It is arranged dimensionally. In the present embodiment, as an example, four measuring units 16 in the X direction are stacked in three stages in the Z direction.

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

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

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

The probe card 32 is provided with a plurality of probes 36 such as a cantilever and a spring pin, which are arranged corresponding to the positions of the electrode pads of each chip of the wafer W to be inspected. Each probe 36 is electrically connected to a terminal of a test head (not shown), a power supply and a test signal are supplied from the test head to each chip via each probe 36, and an output signal from each chip is detected by the test head. And measure whether it works normally. Since the connection configuration between the probe card 32 and the test head is not a main part of the present invention, detailed description thereof will be omitted.

The probe 36 has a spring characteristic, and by raising the contact point from the tip position of the probe 36, the probe 36 comes into contact with the electrode pad at a predetermined contact pressure. Further, when the electrode pad is in contact with the probe 36 in an overdrive state during an electrical inspection, the tip of the probe 36 sinks into the surface of the electrode pad and forms a needle mark on the surface of the electrode pad. It is designed to do. The overdrive is a probe so that the electrode pad and the probe 36 are surely in contact with each other in consideration of the inclination of the wafer W and the arrangement surface of the tip of the probe 36 and the variation in the tip position of the probe 36. A state in which the surface of the electrode pad, that is, the wafer W, is raised by a distance α to a position higher than the tip position of 36. Further, the amount of movement that further raises the surface of the wafer W from the tip position (contact position) of the probe 36, that is, the distance α is referred to as an overdrive amount.

The wafer chuck 34 vacuum-sucks and fixes the wafer W. 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 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 adsorption solenoid valve 46 is controlled by the wafer adsorption solenoid valve control unit 110 (see FIG. 5).

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

The head stage 30 is provided with a suction port 50 for reducing the pressure 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 electropneumatic regulator 54 is provided in the suction path connecting the suction device 44 and the suction path 52. The vacuum electropneumatic regulator 54 is a control valve that adjusts the internal pressure (vacuum degree) of the internal space S. The vacuum electropneumatic 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 electropneumatic regulator 54 are examples of the suction means of the present invention.

Inside the wafer chuck 34, a heating / cooling source is used so that the wafer W to be inspected can be inspected for electrical characteristics in a high temperature state (for example, 150 ° C. at the maximum) or in a low temperature state (for example, −40 ° C. at the minimum). A heating / cooling mechanism (not shown) is provided. As the heating / cooling mechanism, a known appropriate heater / cooler can be adopted. For example, a double-layer structure consisting of a heating layer of a surface heater and a cooling layer provided with a cooling fluid passage, or heat. Various devices such as a single-layer heating / cooling device in which a cooling tube around which a heating heater is wound are embedded in the conductor can be considered. Further, instead of electric heating, a thermal fluid may be circulated, or a Pertier element may be used.

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

The alignment device 70 detachably supports and fixes the wafer chuck 34 to move the wafer chuck 34 in the Z-axis direction, and also has a Z-axis movement / rotation unit 72 that rotates in the θ direction about the Z-axis as a rotation center, and a Z-axis movement. It is provided with an X-axis moving table 74 that supports the rotating portion 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.

The Z-axis moving / rotating unit 72, the X-axis moving table 74, and the Y-axis moving 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. To. The mechanical drive mechanism includes, for example, a ball screw drive mechanism in which a servomotor and a ball screw are combined. Further, the mechanism is not limited to the ball screw drive mechanism, and may be composed of a linear motor drive mechanism, a belt drive mechanism, or the like. The Z-axis moving / rotating unit 72, the X-axis moving table 74, and the Y-axis moving table 76 are configured so that the moving distance, moving direction, moving speed, and acceleration of the wafer chuck 34 can be changed by each control unit described later. ing. Specifically, the present embodiment has the following configuration.

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

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

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

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

The alignment device 70 is provided for each stage (see FIG. 3), and is configured to be mutually movable between a plurality of measuring units 16 arranged in each stage by an alignment device drive mechanism (not shown). .. That is, the alignment device 70 is shared among a plurality of (four in this example) measuring units 16 arranged in the same stage, and moves between the plurality of measuring units 16 arranged in the same stage. do. The alignment device 70 moved to each measuring unit 16 is fixed in a state of being positioned at a predetermined position by a positioning and fixing device (not shown), and the wafer chuck 34 is moved in the X, Y, Z, and θ directions and held by the wafer chuck 34. Relative alignment is performed between the wafer W and the probe card 32. Although not shown, the alignment device 70 includes a needle position detection camera and a needle position detection camera in order to detect the relative positional relationship between the electrode pad of each chip of the wafer W held by the wafer chuck 34 and the probe 36. It is equipped with a wafer alignment camera. The alignment device drive mechanism is composed of a mechanical drive mechanism such as a ball screw drive mechanism, a linear motor drive mechanism, and a belt drive mechanism.

A ring-shaped sealing member (Z-axis sealing rubber) 78 having elasticity formed in an annular shape along the outer periphery is provided on the wafer chuck support surface 72a of the Z-axis moving / rotating portion 72 constituting the upper surface of the alignment device 70. Further, a suction port 80 is provided inside the ring-shaped seal member 78 of the wafer chuck support surface 72a. The suction port 80 is connected to the suction device 44 via a suction path 82 formed inside the wafer chuck 34. In the suction path connecting the suction device 44 and the suction path 82, a chuck fixing solenoid valve 84 and a throttle valve 86 are provided in order from the suction device 44 side. The chuck fixing solenoid valve 84 is controlled by the 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 portion 72 is an example of the wafer chuck fixing portion of the present invention. Further, the suction port 80 provided on the wafer chuck support surface 72a is an example of a component of the wafer chuck fixing portion.

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

In the present embodiment, the alignment device 70 vacuum-sucks and fixes the wafer chuck 34, but any fixing means other than vacuum suction may be used as long as the wafer chuck 34 can be fixed, for example, by mechanical means. It may be fixed.

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

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

The control device 60 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, and the like. In the control device 60, various programs such as control programs stored in the ROM are expanded in the RAM, and the programs expanded in the RAM are executed by the CPU, so that each part in the control device 60 shown in FIG. 5 is executed. Functions are realized, and various arithmetic processing and control processing are executed via the input / output interface.

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, and a wafer suction solenoid valve control. A unit 110, a chuck fixing solenoid valve control unit 112, a suction control unit 114, and the like are provided.

The overall control unit 100 comprehensively controls each unit constituting the prober 10. Specifically, the overall control unit 100 controls an operation (contact operation) in which the electrode pad of each chip of the wafer W to be inspected and each probe 36 of the probe card 32 are brought into contact with each other. Further, in addition to the contact operation, the overall control unit 100 controls the movement of the alignment device 70 to be moved between the measurement units 16 and the operation of the wafer level inspection by the test head. Since the control other than the contact operation is not a characteristic part of the present invention, detailed description thereof will be omitted.

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

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

The chuck fixing solenoid valve control unit 112 adjusts the suction pressure by the suction port 80 by controlling ON / OFF (opening / closing) of the chuck fixing solenoid valve 84, and the wafer with respect to the Z-axis moving / rotating unit 72. The chuck 34 is selectively switched between fixed and non-fixed.

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

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

FIG. 6 is a flowchart showing the contact operation in the prober 10 of the present embodiment. 7 and 8 are diagrams for explaining the contact operation in the prober 10 of the present embodiment. FIG. 9 is a timing chart showing an example of the contact operation in the prober 10 of the present embodiment. The time width of the timing chart shown in FIG. 9 is expressed for the purpose of simplifying the drawing, and is different from the actual time. Further, the "Z-axis height" in FIG. 9 indicates the height position of the Z-axis moving / rotating portion 72 (specifically, the position of the wafer chuck support surface 72a in the Z-axis direction). Further, the "chuck height" in FIG. 9 indicates the height position of the wafer chuck 34 (specifically, the position of the wafer holding surface 34a in the Z-axis direction).

(Preliminary operation)
The pre-operation of the contact operation will be described.

First, as a preliminary operation of the contact operation, the alignment device 70 is moved to the measuring unit 16 to be inspected, and then the wafer chuck 34 is delivered to the alignment device 70 in a state of being positioned and fixed by a positioning and fixing device (not shown). .. Since the transfer operation of the wafer chuck 34 before the start of the contact operation is not a main part of the present invention, detailed description thereof will be omitted.

(Step S10: Wafer chuck fixing process)
After the wafer chuck 34 is delivered to the alignment device 70, as shown by reference numeral 500A in FIG. 7, the chuck fixing solenoid valve control unit 112 sets the chuck fixing solenoid valve 84 to ON (open state) and Z-axis. The wafer chuck 34 is attracted and fixed to the wafer chuck support surface 72a (see FIG. 4) of the moving / rotating portion 72 (time T1 in FIG. 9). At this time, by engaging the positioning pin 88 of the Z-axis moving / rotating portion 72 into the V groove of the V block 90 of the wafer chuck 34, the alignment device 70 and the wafer chuck 34 are relatively positioned.

After that, when the wafer W is supplied (loaded) to the wafer chuck 34 supported and fixed to the alignment device 70, the wafer adsorption solenoid valve control unit 110 turns on the wafer adsorption solenoid valve 46 (open state) and the wafer. The wafer W is adsorbed and fixed to the holding surface 34a (see FIG. 4) (time T2 in FIG. 9).

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

(Step S14: Pre-suction step)
Next, the suction control unit 114 controls the operation of the vacuum electropneumatic regulator 54 and starts suction through the suction port 50 (time T3 in FIG. 9).

Here, in the present embodiment, when controlling the operation of the vacuum electropneumatic regulator 54, the suction control unit 114 controls the suction amount based on the moving speed (rising speed) of the wafer chuck 34 in the Z-axis ascending step described later. do.

Specifically, when the area of the surface (suction surface) surrounded by the ring-shaped sealing member 48 is A [mm ² ] and the moving speed of the wafer chuck 34 is V _z [mm / s], the ring-shaped sealing member After the 48 is in contact with the head stage 30, the internal space S formed between the wafer chuck 34 and the probe card 32 decreases with the movement of the wafer chuck 34 (volume). Since V [mm ³ / s] is expressed by the following equation, control is performed so that the suction amount is at least the volume V or more.

V = AV _z
As a result, when the wafer chuck 34 is moved toward the probe card 32, the volume of the internal space S accompanying the movement of the wafer chuck 34 even after the ring-shaped sealing member 48 is in contact with the head stage 30. Since the gas corresponding to the decrease in (volume) is sucked, the reaction force due to the compression of the internal space S does not occur.

The pre-suction step may be started at least before the ring-shaped seal member 48 comes into contact with the head stage 30 (see reference numeral 500B in FIG. 7) in the Z-axis raising step described later. For example, the pre-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. Further, the pre-suction step may be started at the same time as the wafer chuck fixing step or the alignment step.

(Step S16: Z-axis rising step)
Next, as shown by reference numerals 500B and 500C in FIG. 7, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to raise the Z-axis movement / rotation unit 72 to raise the wafer chuck 34. Move toward the probe card 32 (time T4 to T6 in FIG. 9).

Specifically, the Z-axis movement control unit 106 moves the wafer from the predetermined height position (standby position) H0 to the height position H1 where the ring-shaped seal member 48 contacts the head stage 30. The chuck 34 is raised (see reference numeral 500B in FIG. 7), and the wafer chuck 34 is raised to a position H2 higher than the tip position (contact position) of the probe 36 (see reference numeral 500C in FIG. 7). As a result, each probe 36 of the probe card 32 comes into contact with the electrode pad of each chip of the wafer W in an overdrive state.

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

At this time, in the present embodiment, the pre-suction step is started before the ring-shaped seal member 48 comes into contact with the head stage 30 (see reference numeral 500B in FIG. 7) in the Z-axis ascending step, so that the ring-shaped seal member 48 is ring-shaped. Even after the sealing member 48 comes into contact with the head stage 30 and the internal space S is sealed, it is not affected by the reaction force due to the compression of the internal space S. Therefore, it is possible to prevent abnormal contact between the probe card 32 and the wafer W, and the wafer chuck 34 is stably moved toward the probe card 32 at a moving speed sufficient for removing the oxide film on the electrode pad. It becomes possible.

In the Z-axis raising step, the height at which the wafer chuck 34 is raised by the Z-axis moving / rotating portion 72 is set from the tip position (contact position) of the probe 36 to the appropriate overdrive amount (appropriate OD position) of the probe card 32. The height position is preferably 30 to 70% (more preferably 40 to 60%). The Z-axis raising step is an example of the wafer chuck moving step of the present invention.

(Step S18: Main suction step)
Next, as shown by reference numeral 500D in FIG. 8, the suction control unit 114 controls the operation of the vacuum electropneumatic regulator 54 to continuously perform suction from the suction port 50 following the pre-suction step. , The internal space S is continuously depressurized (time T7 in FIG. 9). At this time, the suction control unit 114 has an appropriate overdrive amount (appropriate OD position H3) of the probe card 32 when the wafer chuck 34 is released from being fixed by the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72. ) Is set so that the wafer chuck 34 rises to the set pressure (target pressure), and the internal pressure of the internal space S is adjusted so as to be the set pressure. The set pressure of the internal space S may be obtained empirically or experimentally, or may be obtained from the design value. For example, in order to determine the set pressure, 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 probe card 32. It can be obtained from the total number of probes 36 provided in the above. Once the total stylus pressure of the probe card 32 (total pressure received from the probe 36) is known, the required negative pressure is set in the internal space S by dividing by the area of the surface (suction surface) surrounded by the ring-shaped sealing member 48. Obtained as pressure. However, it is necessary to set the set pressure of the internal space S in consideration of the weight of the wafer chuck 34 and the reaction force caused by crushing the ring-shaped sealing member 48.

In this embodiment, the case where the pre-suction step and the main suction step are continuously performed is shown, but the present invention is not limited to this, and the pre-suction step is once completed before the main suction step is started. , The main suction process may be started.

(Step S20: Judgment process)
Next, the suction control unit 114 determines whether or not the internal pressure (pressure value P1) of the internal space S has reached the set pressure (pressure value P2) by the vacuum electropneumatic regulator 54. This determination is repeated until the internal pressure (pressure value P1) reaches the set pressure (pressure value P2), and when the set pressure (pressure value P2) is reached, the process proceeds to the next step S22. As a result, when the internal pressure of the internal space S stabilizes at the set pressure, the wafer chuck fixing release step (step S22) described later is performed. The internal pressure of the internal space S may be directly detected by, for example, a pressure sensor provided in the wafer chuck 34 or the head stage 30, or may be built in or connected to the vacuum electropneumatic regulator 54. It may be detected by a pressure sensor.

(Step S22: Wafer chuck fixing release step)
Next, as shown by reference numeral 500E in FIG. 8, the chuck fixing solenoid valve control unit 112 turns off the chuck fixing solenoid valve 84 (closed state), and the suction port 80 of the Z-axis moving / rotating unit 72 (FIG. 8). 4) is released from the fixing of the wafer chuck 34 (time T8 in FIG. 9).

At this time, since the internal pressure of the internal space S is adjusted to the set pressure by the vacuum electropneumatic regulator 54, when the fixing of the wafer chuck 34 by the Z-axis moving / rotating portion 72 is released, the wafer chuck 34 has the Z-axis. It separates from the moving / rotating portion 72, is attracted to the probe card 32 side, and moves to the appropriate OD position H3 (T8 to T9 in FIG. 9). As a result, the electrode pads and the probe card 32 of each chip of the wafer W to be inspected are not affected by the inclination of the wafer W and the arrangement surface of the tip of the probe 36 and the variation of the tip position of the probe 36. The probe 36 is surely in contact with the probe 36 at a predetermined contact pressure.

As described above, in the present embodiment, the wafer chuck 34 is released from being fixed after the decompression of the internal space S is started, so that the wafer chuck 34 is not fixed to either side at the moment of switching between these steps. The (free state) disappears, and the transfer operation of the wafer chuck 34 can be stably performed.

Further, in the present embodiment, since the throttle valve 86 is provided in the suction path connecting between the suction path 82 of the Z-axis moving / rotating portion 72 and the chuck fixing solenoid valve 84, the pressure in the internal space S is reduced. Even if the fixing of the wafer chuck 34 is released after the start of the operation, the negative pressure on the lower side (Z-axis moving / rotating portion 72 side) of the wafer chuck 34 is not suddenly lost. Therefore, the wafer chuck 34 is suddenly restrained from below (that is, the Z-axis moving / rotating portion 72) while being pulled from both the upper and lower sides (that is, both sides of the Z-axis moving / rotating portion 72 and the probe card 32). Since the fixing force due to adsorption from the wafer chuck 34 is not lost, abnormal vibration and abnormal contact due to sudden movement of the wafer chuck 34 can be reduced. Therefore, it is possible to prevent the wafer chuck 34 from suddenly detaching from the Z-axis moving / rotating portion 72 when the wafer chuck fixing release step is performed, so that the transfer operation of the wafer chuck 34 is performed more stably. It becomes possible.

In the present embodiment, as an example, a configuration in which the throttle valve 86 is provided in the suction path connecting between the suction path 82 of the Z-axis moving / rotating portion 72 and the chuck fixing electromagnetic valve 84 is shown. A throttle valve 86 may be provided in the path connecting between the suction port 80 of the shaft moving / rotating portion 72 and the suction device 44. For example, the throttle valve 86 may be provided in the suction path 82 of the Z-axis moving / rotating portion 72. May be provided.

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

As described above, when the wafer chuck 34 is transferred from the alignment device 70 (Z-axis moving / rotating portion 72) to the head stage 30 (probe card 32 side), each probe 36 of the probe card 32 has a uniform contact pressure. The wafer W is in contact with the electrode pads of each chip, and the wafer level inspection can be started. After that, a power supply and a test signal are supplied from the test head to each chip of the wafer W via each probe 36, and the signal output from each chip is detected to perform an electrical operation inspection.

After the wafer chuck 34 is handed over from the alignment device 70 (Z-axis moving / rotating unit 72) to the head stage 30 (probe card 32 side), the alignment device 70 moves to another measuring unit 16 and measures the wafer chuck 34. In the unit 16, the contact operation is performed in the same procedure, and the wafer level inspection is sequentially performed.

Next, the effect of this embodiment will be described.

According to the present embodiment, the pre-suction step is started before the ring-shaped seal member 48 comes into contact with the head stage 30 (see reference numeral 500B in FIG. 7) in the Z-axis ascending step. Therefore, even if the ring-shaped sealing member 48 comes into contact with the head stage 30 and the internal space S is sealed when the wafer chuck 34 is moved toward the probe card 32, the reaction force due to the compression of the internal space S has an effect. Never receive. Therefore, since an unreasonable reaction force (reaction force for returning the wafer chuck 34 to its original position) does not occur in the wafer chuck 34, abnormal contact between the probe card 32 and the wafer W can be prevented, and the probe card 32 can be prevented. And the problem that the wafer W is damaged can be prevented. Further, the wafer chuck 34 can be stably and efficiently moved toward the probe card 32 at a moving speed sufficient for removing the oxide film on the electrode pad. Therefore, good contact can be realized between the electrode pad on the wafer W and the probe 36 without providing the shutter means on the wafer chuck 34.

Further, in the present embodiment, since it is not necessary to provide the shutter means on the wafer chuck 34, the wafer chuck 34 is not provided with the component of the shutter means which is a heat dissipation element, and has an influence on the temperature distribution of the wafer chuck 34. Can be eliminated. Further, the flatness of the wafer holding surface 34a of the wafer chuck 34 is improved by eliminating the influence on the temperature distribution of the wafer chuck 34. As a result, the parallelism between the wafer W and the probe card 32 can be made higher, and the wafer level inspection can be performed with high accuracy. Further, since the number of parts mounted on the wafer chuck 34 can be reduced, it becomes easy to balance the weight of the wafer chuck 34. As a result, the contact operation by the vacuum suction method can be stably performed without disturbing the weight balance of the wafer chuck 34.

Further, in the present embodiment, the wafer chuck 34 is moved up and down (Z direction) by the Z-axis moving / rotating portion 72, so that the electrode pad on the wafer W and the probe 36 are brought into contact with each other a plurality of times in an overdrive state. The operation may be performed. Since the Z-axis moving / rotating unit 72 in the present embodiment is composed of at least a mechanical drive mechanism including a motor (Z-axis drive motor 122), the moving distance, moving speed, and the like of the wafer chuck 34 should be adjusted accurately. Is possible. Further, the Z-axis moving / rotating unit 72 can move the wafer chuck 34 at a sufficiently high moving speed as compared with the case where the wafer chuck 34 is moved toward the probe card 32 by reducing the pressure in the internal space S. Therefore, when the electrode pad on the wafer W and the probe 36 are brought into contact with each other, the oxide film (insulator) on the electrode pad can be removed by the contact of the probe 36, and the wafer W is not damaged. , Good contact can be achieved between the electrode pad on the wafer W and the probe 36.

Further, in the present embodiment, the Z axis is at a timing later (second timing; time T8 in FIG. 9) than the timing (first timing; time T7 in FIG. 9) at which the main suction step (decompression of the internal space S) is started. Since the wafer chuck 34 is released from being fixed by the suction port 80 (see FIG. 4) of the moving / rotating portion 72, the wafer chuck 34 is not fixed to either side at the moment of switching between these processes, which is an unstable state. The (free state) disappears, and the transfer operation of the wafer chuck 34 can be stably performed.

Further, in the present embodiment, since the throttle valve 86 for limiting the flow rate of gas is provided in the path connected to the suction port 80 of the Z-axis moving / rotating portion 72, the chuck fixing solenoid valve 84 is turned off. In this case (when the wafer chuck 34 is open to the atmosphere), it is possible to prevent the wafer chuck 34 from suddenly detaching from the Z-axis moving / rotating portion 72, and the transfer operation of the wafer chuck 34 can be performed more stably.

The prober and probe inspection methods 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 gist of the present invention. Of course it is good.

10 ... Probe, 12 ... Measurement unit, 14 ... Loader unit, 16 ... Measurement unit, 18 ... Load port, 20 ... Wafer cassette, 22 ... Operation panel, 24 ... Transfer unit, 26 ... Transfer arm, 30 ... Head stage, 32 ... Probe card, 34 ... Wafer chuck, 34a ... Wafer holding surface, 36 ... Probe, 40 ... Suction port, 42 ... Suction path, 44 ... Suction device, 46 ... Wafer suction electromagnetic valve, 48 ... Ring-shaped seal member, 50 ... Suction port, 54 ... Vacuum electropneumatic regulator, 56 ... Communication path, 60 ... Control device, 70 ... Alignment device, 72 ... Z-axis moving / rotating part, 72a ... Wafer chuck support surface, 74 ... X-axis moving table, 76 ... Y-axis moving table, 78 ... ring-shaped seal member, 78 ... ring-shaped seal member, 80 ... suction port, 82 ... suction path, 84 ... chuck fixing electromagnetic valve, 86 ... throttle valve, 88 ... positioning pin, 90 ... V block, 92 ... Z-axis movement mechanism, 94 ... θ rotation mechanism, 100 ... Overall control unit, 102 ... X-axis movement control unit, 104 ... Y-axis movement control unit, 106 ... Z-axis movement control unit, 108 ... θ rotation Control unit, 110 ... Wafer suction electromagnetic valve control unit, 112 ... Chuck fixing electromagnetic valve control unit, 114 ... Suction control unit, 118 ... X-axis drive motor, 120 ... Y-axis drive motor, 122 ... Z-axis drive motor, 124 ... Rotary drive motor, W ... Wafer, S ... Internal space

Claims (6)

A wafer chuck that holds the wafer,
A probe card having a plurality of probes on the surface facing the wafer chuck,
A suction means for sucking and holding the wafer chuck on the probe card side by reducing the pressure in the internal space between the wafer chuck and the probe card.
A suction control means for controlling the suction operation by the suction means, the suction control means for initiating the suction operation by the suction means before the internal space is sealed.
Equipped with
After starting the suction operation by the suction means, the wafer chuck is raised to seal the internal space.
Prober. The suction control means sets the suction amount by the suction means based on the moving speed of the wafer chuck.
The prober according to claim 1. The suction amount is determined based on the moving speed of the wafer chuck so that the gas corresponding to the volume reduction of the internal space accompanying the movement of the wafer chuck is sucked.
The prober according to claim 2. A wafer chuck that holds the wafer,
A probe card having a plurality of probes on the surface facing the wafer chuck,
A suction means for sucking and holding the wafer chuck on the probe card side by reducing the pressure in the internal space between the wafer chuck and the probe card.
It is a probe inspection method in a prober equipped with
A wafer chuck moving step of moving the wafer chuck toward the probe card, and
A pre-suction step of initiating a suction operation by the suction means before the internal space is sealed by the wafer chuck moving step, and a pre-suction step.
After the wafer chuck moving step is performed, the main suction step of sucking and holding the wafer chuck on the probe card side by depressurizing the internal space by the suction means.
Probe inspection method. In the pre-suction step, the suction amount by the suction means is set based on the moving speed of the wafer chuck.
The probe inspection method according to claim 4. The suction amount is determined based on the moving speed of the wafer chuck so that the gas corresponding to the volume reduction of the internal space accompanying the movement of the wafer chuck is sucked.
The probe inspection method according to claim 5.

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