JP2674499B2 - Wafer prober - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer prober used for measuring a device circuit formed on a wafer, and more particularly to an apparatus for preparing a measurement environment between the wafer prober and the wafer.

[0002]

2. Description of the Related Art Generally, a wafer prober is used to measure the electrical characteristics of a wafer. To perform this measurement, a large number of probes connected to a tester are provided on the wafer and electrodes are attached to the electrodes. Proper contact is required to make the electrical connection. In this case, since the normal wafer prober has a structure in which the wafer is raised and brought into contact with the probe, it is necessary to correctly set the rising position of the wafer. Therefore, the device shown in the figure has been conventionally proposed. This device is a slight improvement of the one proposed in Japanese Patent Publication No. 62-52457.

As shown in FIG. 4, a subpad 9 having a very small contact resistance is formed on a part of an element circuit formed on a wafer 6 mounted on a stage 5 so as to make good contact with the wafer substrate 7. Keep it. In addition, one probe of the measurement probe is provided as a detection probe on the wafer prober so as to make contact with the subpad 9. Then, the stage drive unit 28 that moves the detection probe 11 up and down by the signal line 4c.
Is connected to the relay 12 of the prober control unit 3 for controlling the.
The relay 12 is controlled by the prober control unit 3 via a signal line 4d, and the stage 5 is formed of a conductive material and is connected to the prober control unit 3 via the relay 12 by a signal line 4b.

In this apparatus, the wafer 6 is brought into close contact with the stage 5 by the vacuum suction force. Further, the prober control unit 3 sends a signal from the open contact to the closed contact of the relay 12 through the signal line 4d to switch the relay 12, and causes the detection probe 11 to apply a voltage through the signal line 4c. Then, when the stage 5 is raised and the detection probe 11 contacts the subpad 9, the current flowing through the wafer substrate 7 is sent to the prober controller 3 through the signal line 4e. By detecting this contact, the prober control unit 3 determines that the probe is in contact with the wafer 6, controls the stage drive unit 28 to stop the ascent of the stage 5, and thereafter, the relay 12 After returning the contacts to their original state, a signal for starting the characteristic measurement is issued.

However, in this wafer prober,
Since it is necessary to form the contact detection subpad 9 in a part of the element circuit, there is almost no room to form an extra electrode other than the element function in the wafer (chip) at the present when the integration of the element has advanced. Therefore, it is difficult to apply it to a highly integrated semiconductor device. Further, in the case where one of the wafer and the prober side is tilted, even if the detection probe 11 is in contact with the sub pad 9, it is not always the case that all of the other probes are in contact with the corresponding pads. However, there is a problem that an accurate measurement result cannot be obtained even if the measurement is performed in that state.

Therefore, in recent years, a wafer prober as shown in FIG. 5 has been proposed. In the figure, stage 5
The wafer to be measured can be placed on it, and is moved up and down by the stage drive unit 28 controlled by the prober control unit 3. The vertical movement position of the stage 5 is stored in a storage device built in the prober control unit 3 or an external storage device. Then, the probe card 22 is arranged above the stage 5, and the tester 23 is placed via the connection ring 21 and electrically connected.

The connection ring 21 has a pogo pin 2 for electrically connecting the tester 23 and the probe card 22.
4 is fixed so as to penetrate, and the pogo pin 24a,
The prober side of 24b is the Pogo seat 25 of the probe card 22.
To be electrically contacted. The pogo seat 25 is connected to a large number of probes 27 provided on the probe card 22 through the probe pattern 26 in the substrate of the probe card 22. The tester 23 side of the pogo pin is brought into contact with and electrically connected to the substrate of the tester 23. The tester 23 is connected to the prober controller 3 by a signal line 4f. Further, the prober control unit 3 is the stage drive unit 2
8 to the signal line 4b.

In this wafer prober, first, a contact wafer 6a whose surface is covered with a conductive film such as an aluminum film is placed on the stage 5 and brought into close contact by vacuum suction, and then a signal from the prober control unit 3 is sent. An operation signal is sent to the stage drive unit 28 by the line 4b to raise the stage 5. Further, the tester 23 activates a contact detection program. And pogo pin 24, pogo seat 2
5 and the probe 27 of the ground level probe group that was first contacted via the probe pattern 26.
Then, the stage 5 continues to rise until it is detected that a current has flowed between the probes 27 in the signal level probe group, and when it is detected, the prober control unit 3 passes through the signal line 4f.
To the stage 5 to stop the rising of the stage 5. The rising position of this stage is stored in the storage device. After that, the stage is once lowered, the wafer to be measured is mounted on the stage, then the stage is raised to the stored rising position, the probe is brought into contact with the wafer, and the characteristic measurement is started by the tester.

[0009]

In such a conventional wafer prober, a contact state is detected by the flow of a current between the two probes that make contact first,
Although the stage position at that time is stored, even in this case, when one of the wafer and the prober is tilted, not all the probes are in contact with each other, and accurate measurement cannot be performed. There is a risk.

Further, in this apparatus, a tester detects that a current has flowed between two of the probe group for the ground level and the probe group for the signal level. When detecting the position, the position of the probe and the number of target will be changed, and in order to cope with this, it is necessary to change the connection on the tester side following the change. There is a problem that it is troublesome and the workability is reduced. An object of the present invention is to provide a wafer prober capable of detecting whether the prober is tilted or not, and performing accurate measurement correspondingly, and capable of promptly responding to a change in element type. is there.

[0011]

SUMMARY OF THE INVENTION A wafer prober of the present invention comprises a stage on which a semiconductor wafer is placed and which is moved up and down, and an electrode of the semiconductor wafer which is arranged above the stage and which is moved upward. Probe card with a large number of probes that are in contact with the probe card, a connection ring with pogo pins that are electrically connected to this probe card, and a probe card that is detachably installed on the connection ring The tester to be connected, the slide substrate arranged on the connection ring and contacting the upper end of the pogo pin when it moves downward, the vertical movement of the stage can be controlled, and the movement height position thereof can be stored, and It is equipped with a prober controller that can detect the contact state between the probe and the wafer when a signal from the probe card is input. Is vertically moved with respect to the connection ring with emissions tact pattern is formed, configured to electrically connect to the prober controller pogo pins through the contact pattern when it is moved downward.

Here, on the upper surface of the connection ring, there are provided a base board having a contact seat connected to the pogo pin, a connector pin electrically connected to the prober control section, and a drive section for vertically moving the slide board. The slide board is provided with a contactor arranged at a position facing the contact seat, and a terminal connected to the contactor via a contact pattern and facing the connector pin, and the drive section moves the slide board downward. The contactor and the contact seat are electrically contacted with each other, and the connector pin and the terminal are electrically contacted with each other. Also, the prober control unit
A storage device capable of storing at least the stage height at which the probe first contacts the wafer as the stage moves up and the stage height at which the probe finally contacts the wafer are provided.
Further, the prober control unit is provided with a relay that switches and connects the stage between the ground line and the bais line of the tester. Further, preferably, the slide substrate is attachable / detachable to / from the connection ring and is configured to be replaceable with another slide substrate having a different contact pattern.

[0013]

[Function] The probe card is electrically connected to the prober control unit by moving the slide substrate downward, and the prober control unit sequentially detects the contact state between the probe and the wafer while raising the stage in this state, and the first contact height is detected. And the last contact height are memorized, the quality of the probe card is detected by calculating the difference between the heights, and the stage is set to the last contact height position stored during wafer measurement. Wafer measurement is possible.

[0014]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is A of FIG.
It is a part enlarged view. In FIG. 1, the stage 5 on which a wafer is placed is configured to be vertically moved by a stage drive unit 28. The stage drive unit 28 is controlled by the prober control unit 3, and the prober control unit 3 has a built-in storage device for storing the vertical movement position of the stage 5. A relay 12 is attached to the prober control unit 3.

On the other hand, a probe card 22 supporting a large number of probes is arranged above the stage 5 and is electrically connected to a connection ring 21 fixedly supported on the head plate 20. The required number of pogo pins 24 are installed on the connecting ring 21 so as to penetrate the connecting ring 21 in the ring plate thickness direction while being insulated from the connecting ring 21.
In particular, the lower portion of the pogo pin 24 is brought into contact with the pogo seat 25 provided on the probe card 22 here. The pogo seat 25 is electrically connected to a probe 27 by a probe pattern 26 provided on the probe card 22.

The upper portion of the pogo pin 24 projects above the connection ring 21. As shown in FIG. 2, the protruding portion of the pogo pin 24 is connected to the connection ring 21.
Through the through hole 41 provided in the base substrate 30 fixed on the upper surface of the substrate while maintaining insulation. Then, the cylindrical contact seat 2 with a collar fitted in the through hole 41
9 is electrically and mechanically connected by a conductive adhesive 42 such as solder.

Further, at a position facing the base substrate 30, a slide substrate 31 provided with a through hole 41 through which the projecting portion of the pogo pin 24 is inserted is arranged. The through hole 41 of the slide substrate 31 is merely a through hole, is formed to have a diameter slightly larger than the pogo pin 24, and the contact seat 29 of the base substrate 30 is formed on the lower surface of the slide substrate 31 surrounding the through hole 41.
There is provided an annular contactor 32 that can be brought into contact with. Further, a contact pattern 33 formed according to the contact detection condition is connected to the contact 32.

As shown in FIG. 1, the contact pattern 33 is connected at its end to a terminal 43 provided on one side of the slide substrate 31. The terminal 43 is arranged at a position facing the connector pin 34 attached to the outer circumference of the connection ring 21, and is brought into contact with the connector pin 34 when the slide substrate 31 is moved downward. The connector pin 34 is connected to the contact signal line 5
0 is connected to the prober control unit 3. The slide substrate 31 is detachably connected to rods 36 of a driving device 35 evenly arranged on the outer periphery of the connecting ring 21, and is vertically moved by the driving device 35 with respect to the connecting ring 21. It has become so. The drive device 35 is connected to the prober control unit 3 by a drive signal line 51.

The stage 5 is the stage drive unit 2
8 works in conjunction with, but is electrically isolated,
It is connected to the common of the relay 12 of the prober control unit 3 by the signal line 4e. When the relay 12 is not in operation, the common is connected to the lower terminal in the figure, and this terminal is connected to the contact on the bias line 40 side of the tester (not shown). Further, the relay 12 has a common connected to the upper terminal in the drawing when it is operated, and is connected to the prober control unit 3. 3 shows the prober control unit 3, the relay 12, the probe 27.
FIG. 9 is a schematic wiring diagram showing a mutual connection state of a plurality of probes, in which a large number of probes are divided into a plurality of groups, and each group has a connector pin 34 and contact signal lines 50a-50.
The prober control unit 3 is connected by d.

Next, the operation of this embodiment having the above configuration will be described. First, the contact wafer 6a whose surface is covered with a conductive film is placed on the stage 5. At the same time, the contact of the relay 12 of the prober control unit 3 is switched by the signal from the signal line 4d to electrically bring the stage 5 to the ground level, and the prober control unit 3 sends an operation signal through the drive signal line 51 to the driving device 35. Feed rod 36 is shortened to move slide substrate 31 downward, and contact 32
Are electrically contacted with the contact seats 29 of the base substrate 30. Further, the terminal 43 connected to the contactor 32 via the contact pattern 33 is connected to the connector pin 34 arranged on the outer circumference of the connection ring 21, and the prober control unit 3 is connected.
A constant voltage is applied to the probe 27 via the contact signal line 50.

Next, the stage drive unit 28 is connected to the signal line 4b.
Sends an ascending signal to raise the stage 5. When at least one of the probes 27 comes into contact with the contact wafer 6a, an electric circuit is formed, and the prober controller 3 is connected via the relay 12 which connects the contact wafer 6a, the stage 5 and the signal line 4e. Current flows to. As a result, the prober control unit 3 can detect the presence of the first contact, and store the contact height at that time and in which of the contact signal lines 50a to 50d the current flows in the built-in storage device.

Further, the stage 5 is raised to sequentially detect the probe 27 and the contact signal line at that time which are sequentially contacted with the contact wafer 6a by the prober control unit 3, and the contact height and the contact signal line at that time are stored in the storage device. Remember. This operation is repeated, and when it is detected that the last contacted signal line is contacted, the prober control unit 3 stops the ascending operation of the stage 5. Also,
Memorize this stage height. Then, calculate the difference in contact height between the first and last contacted probes,
When this difference exceeds a value preset by an internal parameter of the wafer prober, an alarm is issued and it is determined that the probe card 22 is extremely inclined,
The abnormality of the probe card 22 is notified. Upon receiving this notification, the worker replaces the probe card 22.

After replacing the probe card 22, the above-mentioned operation is performed again. Then, if the obtained difference in contact height is within the set value, a signal is sent from the prober control unit 3 to the drive device 35 through the drive signal line 51,
The slide board 31 is lifted to separate the contact seat 29 of the base board 30 and the contact 32 of the slide board 31 from the connector pin 34, and the relay 12 of the prober control unit 3 is switched by the signal line 4d to bias the tester. Connect to line 40.

Thereafter, as shown in FIG. 5, the tester 23 is placed on the connection ring 21, and the pogo pin 24 of the connection ring 21 is brought into electrical contact with the tester 23. Further, the stage 5 is lowered once, and then a wafer (not shown) to be measured is placed thereon instead of the contact wafer, and the stage 5 has the highest stage height stored in the prober controller 3. Raise it up to As a result, all the probes 27 come into contact with the wafer, and in this state, the tester 23 energizes the wafer and executes accurate measurement of the wafer. For this reason, when the prober side is extremely inclined, it can be replaced as an abnormality, so that it is possible to always perform normal wafer measurement with the prober. Also,
Even if the wafer side is slightly tilted, all the probes 27
Since the position of the stage 5 is set in a state of being in contact with the wafer, accurate measurement is always possible.

Further, when the type of element on the wafer is changed or the probe card 22 is changed, the slide substrate 3 formed with different contact patterns.
If it is replaced with 1, the connection between each probe 22 and the prober control unit 3 can be changed to set the stage position according to the element type, and the work can be simplified. Further, since the optimum position of the wafer can be detected without using a tester, it is possible to eliminate mechanical restrictions such as a large test head at this time.

[0026]

As described above, according to the present invention, the probe board can be electrically connected to the prober control section with a required circuit configuration by vertically moving the slide substrate provided on the connection ring, and the prober control section is the probe card. It is possible to detect the height of the stage from the state of contact with the wafer in step 1, and to detect the quality of the probe card from this, and also to detect the stage height suitable for wafer measurement. As a result, accurate measurement can be realized even when the prober or wafer is tilted. Further, the prober alone can detect the suitable position of the stage without using a tester, so that there is no mechanical limitation such as a large test head. Further, by exchanging the slide substrate with one having a different contact pattern, it becomes possible to detect whether the probe card is good or bad and a suitable stage position according to the type of the probe card or element.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of a wafer prober of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a schematic circuit diagram of the embodiment shown in FIG.

FIG. 4 is a schematic cross-sectional view of a conventionally proposed wafer prober.

FIG. 5 is a cross-sectional view of an example of a conventional improved wafer prober.

[Explanation of symbols]

 3 Prober Control Section 5 Stage 6 Wafer 6a Contact Wafer 21 Connection Ring 22 Probe Card 23 Tester 24 Pogo Pin 27 Probe 31 Slide Substrate

Claims (5)

(57) [Claims] 1. A stage including a stage on which a semiconductor wafer is placed and which is moved up and down, and a plurality of probes which are arranged above the stage and which are brought into contact with electrodes of the semiconductor wafer when the stage is moved upward. A probe card, a connection ring having pogo pins electrically connected to the probe card, a tester removably installed on the connection ring and electrically connected to the probe card via the pogo pins, and the connection A slide substrate arranged on the ring and brought into contact with the upper end of the pogo pin when the slide substrate moves downward;
Along with controlling the vertical movement of the stage, it is possible to store the moving height position, and comprises a prober control unit capable of detecting the contact state between the probe and the wafer when a signal from the probe card is input, The slide substrate has a contact pattern formed thereon and can move up and down with respect to the connection ring. When the slide substrate is moved down, the pogo pin is electrically connected to the prober control unit via the contact pattern. Wafer prober. 2. The upper surface of the connection ring is provided with a base board having a contact seat connected to a pogo pin, a connector pin electrically connected to the prober control section, and a drive section for moving the slide board up and down. The board is provided with a contactor at a position facing the contact seat, and a terminal connected to the contactor via a contact pattern and facing the connector pin, and when the slide board is moved downward by the driving unit. The wafer prober according to claim 1, wherein the contactor and the contact seat are electrically contacted with each other, and the connector pin and the terminal are electrically contacted with each other. 3. The prober control unit includes a storage device capable of storing at least a stage height at which the probe first contacts the wafer as the stage moves upward and a stage height at which the probe finally contacts the wafer. 1 or 2 wafer prober. 4. The wafer prober according to claim 3, wherein the prober control section is provided with a relay for switching and connecting the stage between a ground line and a baice line of the tester. 5. The wafer prober according to claim 2, wherein the slide substrate is attachable to and detachable from the connection ring, and can be replaced with another slide substrate having a different contact pattern.