JP7045631B2 - Prover and probe inspection method - Google Patents

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 products are 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 power and test signals are supplied from the test head to each chip via the probe, and the output signal from each chip is detected by the test head 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, it is grasped whether or not an appropriate overdrive amount can be secured when the electrode pads of each chip of the wafer are brought into contact with each probe of the probe card by depressurizing the internal space. That is difficult. If an appropriate amount of overdrive cannot be secured, the contact pressure required for electrical conduction between the probe and the electrode pad cannot be secured, and accurate inspection cannot be performed.

The present invention has been made in view of such circumstances, and it is possible to grasp whether or not an appropriate amount of overdrive is secured, and to realize good contact between the electrode pad on the wafer and the probe. It is an object of the present invention to provide a prober and probe inspection method capable of performing.

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

The prober according to the first aspect of the present invention includes a wafer chuck for holding a wafer, a probe card provided so as to face the wafer chuck and having a probe at a position corresponding to each electrode pad of the wafer, and a wafer chuck and a probe. An internal space was formed by an annular seal member that forms an internal space between the card and the wafer chuck, a mechanical elevating means that supports the wafer chuck detachably and raises and lowers the wafer chuck toward the probe card, and a seal member. In the state, the decompression means for performing step decompression in which the depressurization of the internal space is divided into a plurality of steps and the depressurization is performed stepwise, and the height at which the height position of the wafer chuck is detected for each step when the step decompression is performed. A position detecting means and an overdrive amount calculating means for calculating an overdrive amount when the probe and the electrode pad come into contact with each other based on the detection result of the height position detecting means are provided.

In the prober according to the second aspect of the present invention, in the first aspect, the overdrive amount calculation means is a wafer chuck when the height position of the wafer chuck per step is changed when the step depressurization is performed. The height position of is determined to be the contact position where the probe and the electrode pad have started to contact, and the overdrive amount is calculated with the contact position as a reference position.

In the prober according to the third aspect of the present invention, in the first aspect or the second aspect, the height position detecting means is a non-contact type distance sensor arranged at a position away from the wafer chuck.

In the probe inspection method according to the fourth aspect of the present invention, in a state where an internal space is formed between the wafer chuck and the probe card, the depressurization of the internal space is divided into a plurality of steps and the step decompression is performed stepwise. Probe card probe and wafer based on the detection results of the decompression step to be performed, the height position detection step to detect the height position of the wafer chuck step by step when step decompression is being performed, and the height position detection step. A step of calculating an overdrive amount when the electrode pad on the wafer held by the chuck comes into contact with the electrode pad is provided.

In the fourth aspect of the probe inspection method according to the fifth aspect of the present invention, in the overdrive amount calculation step, when the height position of the wafer chuck per step changes when the step depressurization is performed. The height position of the wafer chuck is determined to be the contact position where the probe and the electrode pad have started to contact, and the overdrive amount is calculated with the contact position as a reference position.

In the probe inspection method according to the sixth aspect of the present invention, in the fourth or fifth aspect, the height position detection step is a wafer using a non-contact distance sensor arranged at a position away from the wafer chuck. Detects the height position of the chuck.

According to the present invention, it is possible to grasp whether or not an appropriate amount of overdrive is secured, and it is possible to realize good contact between the electrode pad on the wafer and the probe.

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 which showed an example of the relationship between the internal pressure of an internal space and the height position of a wafer chuck when the contact operation is performed 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 vacuum electropneumatic regulator 54 is an example of the depressurizing 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, moves the wafer chuck 34 in the Z-axis direction, and rotates in the θ-direction with the Z-axis as the center of rotation. 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 between 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.

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.

In addition to the above configuration, the prober 10 in the present embodiment further includes a distance sensor (length measuring sensor) 38. The distance sensor 38 is an example of the height position detecting means of the present invention, and detects the height position (position in the Z direction) of the wafer chuck 34. As the distance sensor 38, various sensors can be used regardless of whether they are contact type or non-contact type as long as the height position of the wafer chuck 34 can be detected. However, the height of the wafer chuck 34 to be measured is high. A non-contact sensor that does not affect the position is desirable. As the non-contact type sensor, a non-contact type distance sensor using a laser or ultrasonic waves (for example, a laser length measuring sensor or the like) is preferably used. The distance sensor 38 in the present embodiment is a non-contact type distance sensor, and is attached to the sensor mounting portion of the Z-axis moving / rotating portion 72. The distance sensor 38 detects the height position (position in the Z-axis direction) of the wafer chuck 34 by measuring the distance from the distance sensor 38 to the wafer chuck 34.

The location of the distance sensor 38 is not particularly limited to this embodiment, and may be arranged on the head stage 30 side (for example, the head stage 30 or the probe card 32).

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.

Further, the overall control unit 100 in the present embodiment includes an overdrive amount calculation unit 115. The overdrive amount calculation unit 115 functions as the overdrive amount calculation means of the present invention, and calculates the overdrive amount when each probe 36 of the probe card 32 and the electrode pad of each chip of the wafer W come into contact with each other. do.

Further, a distance sensor 38 is connected to the overall control unit 100. As described above, the distance sensor 38 detects the height position (position in the Z direction) of the wafer chuck 34. The detection result of the distance sensor 38 is stored in a storage device (not shown) of the control device 60. The storage device is composed of a literate storage device such as a RAM or an HDD.

The overdrive amount calculation unit 115 acquires the detection result of the distance sensor 38 from the above-mentioned storage device. Then, the overdrive amount calculation unit 115 calculates the overdrive amount based on the detection result of the distance sensor 38. The method of calculating the overdrive amount will be described later.

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 8. 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. FIG. 7 is a diagram for explaining a contact operation in the prober 10 of the present embodiment. FIG. 8 is a diagram showing an example of the relationship between the internal pressure (negative pressure) of the internal space S and the height position of the wafer chuck 34 when the contact operation in the prober 10 of the present embodiment is performed.

(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.

After the wafer chuck 34 is delivered to the alignment device 70, the chuck fixing solenoid valve control unit 112 turns the chuck fixing solenoid valve 84 ON (open state), and the wafer chuck support surface of the Z-axis moving / rotating unit 72 is turned on. The wafer chuck 34 is attracted and fixed to 72a (see FIG. 4). 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).

(Step S10: 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 S12: Z-axis rising step)
Next, as shown by reference numerals 500A and 500B in FIG. 7, the Z-axis movement control unit 106 controls the Z-axis drive motor 122 to raise the Z-axis movement / rotation unit 72, thereby causing the ring-shaped seal member. The wafer chuck 34 is moved toward the probe card 32 to a height position where the 48 contacts the lower surface of the head stage 30. As a result, the ring-shaped sealing member 48 comes into contact with the lower surface of the head stage 30, and the internal space S formed between the wafer chuck 34 and the probe card 32 is sealed from the outside.

(Step S14: Decompression step)
Next, as shown by reference numeral 500C in FIG. 7, the suction control unit 114 controls the operation of the vacuum electropneumatic regulator 54 to start depressurizing the internal space S through the suction port 50 (time in FIG. 8). t ₀ ). At this time, the suction control unit 114 divides the decompression of the internal space S into a plurality of steps and performs step decompression in which the decompression is performed stepwise. Specifically, as shown in the graph shown in the upper part of FIG. 8 (graph showing the temporal change of the internal pressure in the internal space), the internal pressure in the internal space S changes from the initial pressure P ₀ to the set pressure P ₁ . Until then, the internal pressure (negative pressure) of the internal space S is controlled to be gradually increased by a minute pressure ΔP at intervals of Δt for a certain period of time.

Further, in the depressurizing step, the wafer chuck fixing release step is performed at the same time as or after the start of the depressurizing step. In the wafer chuck fixing release step, the chuck fixing solenoid valve control unit 112 turns off the chuck fixing solenoid valve 84 (closed state), and the wafer chuck is provided by the suction port 80 (see FIG. 4) of the Z-axis moving / rotating unit 72. Release the fixing of 34. As a result, when the decompression step is performed, the wafer chuck 34 moves (rises) toward the probe card 32 side according to the internal pressure of the internal space S.

Here, in the present embodiment, since the throttle valve 86 is provided in the suction path connecting the suction path 82 of the Z-axis moving / rotating portion 72 and the chuck fixing solenoid valve 84, the pressure reducing step is started. Even if the wafer chuck fixing release step is performed at the same time as or later than that, the negative pressure on the lower side (Z-axis moving / rotating portion 72 side) of the wafer chuck 34 is not suddenly lost. There is. 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 this embodiment, as an example, a throttle valve 86 is provided in the suction path connecting the suction path 82 of the Z-axis moving / rotating portion 72 and the chuck fixing electromagnetic valve 84, but Z A throttle valve 86 may be provided in the path connecting 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 S16: Height position detection step)
The distance sensor 38 detects the height position of the wafer chuck 34 step by step when the step depressurization of the internal space S is performed. The detection result of the distance sensor 38 is output to and stored in a storage device (not shown) of the control device 60.

(Step S18: Judgment step)
Next, the suction control unit 114 determines whether or not the internal pressure of the internal space S has reached the set pressure P ₁ . If the internal pressure of the internal space S has not reached the set pressure P ₁ (No in step S18), the process returns to step S14 and the processes after step S14 are repeated. On the other hand, when the internal pressure of the internal space S reaches the set pressure P ₁ (Yes in step S18), the process proceeds to the next step S20.

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 S20: Contact position detection step)
Next, the overdrive amount calculation unit 115 acquires the detection result of the distance sensor 38 from the storage device (not shown) of the control device 60. Then, the overdrive amount calculation unit 115 detects the contact position (reference position) at which the probe 36 and the electrode pad on the wafer W start to come into contact with each other based on the detection result of the distance sensor 38. Specifically, the contact position is detected as follows.

The graph shown in the lower part of FIG. 8 is a graph showing the temporal change of the height position of the wafer chuck 34 when the step depressurization of the internal space S (see the graph shown in the upper part of FIG. 8) is performed. As shown in this graph, when the step depressurization of the internal space S is performed, the height position of the wafer chuck 34 changes by the minute height Δh each time the internal pressure of the internal space S changes by the minute pressure ΔP. .. At this time, before and after the probe 36 and the electrode pad on the wafer W come into contact with each other, the amount of change in the height position of the wafer chuck 34 per step (small height Δh) is different. That is, after the probe 36 and the electrode pad on the wafer W come into contact with each other, the wafer chuck 34 receives a reaction force (reaction force when the probe 36 is crushed) from each probe 36, and therefore, before they come into contact with each other. In comparison, the amount of change in the height position of the wafer chuck 34 per step is small.

The overdrive amount calculation unit 115 utilizes the characteristic that the movement amount of the wafer chuck 34 per step changes before and after the probe 36 and the electrode pad on the wafer W come into contact with each other when the internal space S is stepped down. , Detects the contact position where the probe 36 and the electrode pad on the wafer W start to come into contact with each other.

For example, in the example shown in FIG. 8, the amount of change in the height position of the wafer chuck 34 per step changes at time t _s . In this case, the overdrive amount calculation unit 115 detects the height position H ₀ of the wafer chuck 34 at time _ts as the contact position. If the reaction force of the ring-shaped sealing member 48 is very small, the amount of change in the height position of the wafer chuck 34 per step may change immediately after the step depressurization of the internal space S is started. ..

(Step S22: Overdrive amount calculation step)
Next, the overdrive amount calculation unit 115 determines the height position H ₁ of the wafer chuck 34 when the internal pressure of the internal space S reaches the set pressure P ₁ and the contact position H detected in the above-mentioned contact position detection step. The difference from ₀ is calculated as the overdrive amount D.

The overdrive amount calculation unit 115 outputs the calculated overdrive amount D to a monitor (not shown). As a result, the overdrive amount D is displayed on the monitor. Therefore, the operator can grasp the overdrive amount D by checking the display on the monitor.

The suction control unit 114 sets the pressure so that the overdrive amount falls within an appropriate range when the overdrive amount calculated by the overdrive amount calculation unit 115 is not appropriate under the control of the overall control unit 100. Control to change P ₁ may be performed. Further, the operator may manually change the set pressure _P1 .

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.

As described above, according to the present embodiment, the height position of the wafer chuck 34 can be detected step by step while the internal space S is stepped down, and the overdrive amount can be calculated from the detection result. Therefore, the operator can easily and accurately grasp whether or not an appropriate amount of overdrive can be secured, and can realize good contact between the electrode pad on the wafer W and the probe 36.

In particular, in the present embodiment, on the wafer W, based on the amount of change in the height position of the wafer chuck 34 per step (movement amount of the wafer chuck 34 per step) when the step decompression of the internal space S is performed. The contact position where the electrode pad and the probe 36 start to come into contact with each other is detected, and the amount of overdrive is calculated based on the contact position. Therefore, even if there is an error between the design value of the probe card 32 and the actual product dimensions, it is possible to accurately grasp whether or not an appropriate overdrive amount can be secured without being affected by the error. It becomes possible to do. As a result, the electrode pad on the wafer W and the probe 36 are surely in contact with each other, and a highly reliable inspection can be performed.

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, 38 ... Distance sensor, 40 ... Suction port, 42 ... Suction path, 44 ... Suction device, 46 ... Wafer suction electromagnetic valve, 48 ... Ring Shape 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 Shaft 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 ... Squeeze 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 adsorption electromagnetic valve control unit, 112 ... Chuck fixing electromagnetic valve control unit, 114 ... Suction control unit, 115 ... Overdrive amount calculation 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 provided so as to face the wafer chuck and having a probe at a position corresponding to each electrode pad of the wafer.
An annular sealing member forming an internal space between the wafer chuck and the probe card,
A mechanical elevating means that detachably supports the wafer chuck and raises and lowers the wafer chuck toward the probe card.
A decompression means for performing step decompression in which the decompression of the internal space is divided into a plurality of steps and the decompression is performed stepwise in a state where the internal space is formed by the sealing member.
A height position detecting means for detecting the height position of the wafer chuck for each step when the step depressurization is performed,
An overdrive amount calculating means for calculating the overdrive amount when the probe and the electrode pad come into contact with each other based on the detection result of the height position detecting means.
Prober equipped with. The overdrive amount calculation means determines the height position of the wafer chuck when the height position of the wafer chuck per step changes when the step decompression is performed, and the probe and the electrode pad. The overdrive amount is calculated with the contact position as a reference position, determining that the contact position has begun to come into contact with.
The prober according to claim 1. The height position detecting means is a non-contact type distance sensor arranged at a position away from the wafer chuck.
The prober according to claim 1 or 2. In a state where an internal space is formed between the wafer chuck and the probe card, a decompression step of dividing the decompression of the internal space into a plurality of steps and gradually depressurizing the internal space, and a decompression step of performing decompression.
A height position detection step of detecting the height position of the wafer chuck step by step when the step decompression is performed, and a height position detection step.
An overdrive amount calculation step of calculating the overdrive amount when the probe of the probe card and the electrode pad on the wafer held by the wafer chuck come into contact with each other based on the detection result of the height position detection step.
Probe inspection method. In the overdrive amount calculation step, the probe and the electrode pad determine the height position of the wafer chuck when the height position of the wafer chuck per step changes when the step decompression is performed. The overdrive amount is calculated with the contact position as a reference position, determining that the contact position has begun to come into contact with.
The probe inspection method according to claim 4. In the height position detection step, the height position of the wafer chuck is detected by using a non-contact distance sensor arranged at a position away from the wafer chuck.
The probe inspection method according to claim 4 or 5.

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