JP2008294292A - Prober, contacting method and program for prober - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and program for obtaining a prober at a low cost which permits quick contacting operation of the prober to an electrode in the prober, for improved throughput. <P>SOLUTION: The prober is equipped with a wafer chuck for retaining a wafer, an XY-moving mechanism and a Z-moving mechanism for moving the wafer chuck into the directions of X, Y and Z axes, a head stage 13 for retaining a probe card 23 and a head stage supporting mechanism, which changes the inclination of the head stage 13 and moves the same while being equipped with a motor 51, a gear 52, a feeding screw mechanism 54, a guide 56 and the like. Upon contacting an electrode with the probe 24, the electrode is moved to a position immediately below the probe by the XY-moving mechanism and, thereafter, the electrode is moved to a predetermined position, whereat the electrode is contacted with the probe, by the Z-moving mechanism, then, the head stage 13 is moved by the head stage supporting mechanism thereafter to contact the probe with the electrode under a contacting pressure within a predetermined range. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a prober, a probe contact method, and a program for connecting electrodes of a semiconductor chip to a tester in order to perform electrical inspection of a plurality of semiconductor chips (dies) formed on a semiconductor wafer.

  In the semiconductor manufacturing process, various processes are performed on a thin disk-shaped semiconductor wafer to form a plurality of chips (dies) each having a semiconductor device (device). Each chip is inspected for electrical characteristics, then separated by a dicer, and then fixed to a lead frame and assembled. The inspection of the electrical characteristics is performed using a prober and a tester. The prober fixes the wafer to the wafer chuck and brings the probe into contact with the electrode pad of each chip. The tester supplies power and various test signals from the terminals connected to the probe, and analyzes the signals output to the electrodes of the chip with the tester to check whether it operates normally.

  FIG. 1 is a diagram showing a schematic configuration of a conventional wafer test system including a prober 10 and a tester 30. As shown in the figure, the prober 10 has a housing composed of a base member 11, a plurality of struts 12 provided on the base member 11, and a head stage 13 provided on the plurality of struts 12. . The base member 11 includes a Y moving base 14, a Y moving member 15 that moves on the Y moving base 14, a Y moving portion 16 attached to the Y moving member 15, and an X provided on the Y moving portion 16. A moving base 17, an X moving member 18 that moves on the X moving base 17, an X moving portion 19 attached to the X moving member 18, and a Z moving mechanism and a θ rotation mechanism provided on the X moving portion 19. A chuck moving mechanism including a Z / θ mechanism unit 20 to be accommodated and a wafer chuck 21 provided in the Z / θ mechanism unit 20 is provided. The wafer W to be inspected is placed on the wafer chuck 21 and fixed by vacuum suction or the like. The fixed wafer W can be moved in three axial directions by the chuck moving mechanism, and can be rotated about the Z axis.

  The head stage 13 is provided with a hole 25, and a probe card 23 is attached to the hole 25. The probe card 23 is provided with an elastic probe 24 of a cantilever type or a spring pin type, and the probe 24 contacts an electrode of a device (die) formed on the wafer W to be inspected. The probe 24 needs to be arranged according to the electrode arrangement of the device, and the probe card 23 is exchanged according to the device to be inspected. Here, the configuration in which the probe card 23 is directly attached to the head stage 13 is shown, but there may be a case where a card holder is provided on the head stage 13 and the probe card 23 is attached to the card holder.

  The tester 30 includes a tester body 31 and a contact ring 32 provided on the tester body 31. The tester body 31 is held with respect to the prober 10 by a support mechanism (not shown). The contact ring 32 is provided with a spring probe. The contact ring 32 is brought close to the probe card 23 so that the spring probe is brought into contact with a terminal provided on the upper surface of the probe card 23. The terminals are connected to the probes 24, and the probe 24 and the tester 30 are thus connected.

  The prober 10 is also provided with a needle alignment camera that detects the position of the probe and a wafer alignment camera that detects the electrode position of the die of the wafer W. is doing.

  Further, since semiconductor devices are used in a wide temperature range, it is necessary to inspect them under various temperature conditions. Therefore, in order to heat or cool the wafer W held on the wafer chuck 21, a temperature adjustment mechanism for changing the temperature of the wafer chuck 21 such as a heater mechanism, a chiller mechanism, or a heat pump mechanism may be provided in the wafer chuck 21. However, illustration is omitted here.

  When inspection is performed, a relative position between the die electrode of the wafer W held on the wafer chuck 21 and the probe 24 is detected by a needle alignment camera and a wafer alignment camera (not shown), and the arrangement direction of the die electrodes is determined. The wafer chuck 21 is rotated so as to coincide with the arrangement direction of the probes 24, the electrode of the die to be inspected is moved so as to be positioned below the probe 24, the wafer chuck 21 is raised, and the electrode pad is attached to the probe 24. Make contact.

  The probe 24 is elastic and contacts the electrode with a predetermined contact pressure by raising the contact point from the tip position of the probe. In consideration of the inclination of the wafer W and the arrangement surface of the tip of the probe 24 and the variation in the tip position of the probe 24, the electrode is positioned up to a position higher than the tip position of the probe 24 so that the electrode pad and the probe 24 are in reliable contact The surface of the pad, that is, the wafer W is raised. This is referred to as overdrive, and the amount of movement that further raises the surface of the wafer W from the detected tip position of the probe 24 is referred to as overdrive amount. Therefore, if all the probes are in contact with the electrodes of the wafer at a predetermined contact pressure, a contact pressure obtained by multiplying the contact pressure of one probe by the number of probes is applied to the entire wafer chuck 21.

  In recent years, in order to improve throughput, multi-probing processing for inspecting a plurality of dies simultaneously has been performed, and the number of probes may be several tens of thousands. In such a case, the probe card 23 and A very large contact pressure is applied to the wafer chuck 21 as a whole.

  The configuration of the prober described above is widely known and described in, for example, Patent Documents 1 and 2.

  The probe card 23 is replaced according to the wafer W to be inspected. In order for each probe 24 to contact at a contact pressure within a predetermined range of the electrodes, the tip portions of the plurality of probes 24 of the probe card 23 form a plane, and this plane is required to be parallel to the wafer chuck 21.

  Therefore, the head stage 13 has a reference surface for attaching the probe card 23, and the probe card 23 is manufactured so that the tip portion of the probe 24 is flat with respect to the reference surface. Then, adjustment is performed so that the reference surface of the head stage 13 is parallel to the wafer chuck 21. Specifically, a mechanism for moving the tips of the plurality of columns 12 up and down independently by a push screw mechanism or the like is provided so that the inclination of the head stage 13 can be adjusted, and the reference surface of the head stage 13 and the wafer chuck 21 are mounted. While measuring the interval between the mounting surfaces and the change thereof, the inclination of the head stage 13 is adjusted and fixed so that the reference surface of the head stage 13 and the mounting surface of the wafer chuck 21 are parallel. This adjustment was done manually.

Japanese Patent Laid-Open No. 10-150081 JP 2002-170855 A

  As described above, in order to improve the throughput, multi-probing processing in which a plurality of dies are inspected at the same time is performed, and the number of probes may be several tens of thousands, for example, 20,000 probes each. When the electrode is contacted with a contact pressure of 5 g or more, a pressure (load) of 100 kg or more is applied to the wafer chuck 21, the probe card 23, and the head stage 13. Therefore, as a matter of course, the wafer chuck 21, the probe card 23, the head stage 13, and the like are configured to withstand such pressure. In recent years, it has been studied to further increase the number of probes, and the applied load is assumed to be 200 kg or more.

  The Y moving member 15 and the X moving member 18 do not have any problem as long as the load resistance in a stationary state is equal to or higher than the above load because the probe and the electrode are not in contact when the wafer chuck 21 is moved. On the other hand, the Z moving mechanism by the Z · θ mechanism unit 20 needs to move the wafer chuck 21 in a state where the probe and the electrode are in contact, and the same load as that in the stationary state is applied in the final state of the movement. become. Therefore, the Z moving mechanism is required to be movable with such a load. In order to realize such a load resistance during operation, a motor that generates high torque is used as a motor that drives the Z movement mechanism, or a reduction gear using a gear is used.

  The prober is required to have high throughput and low cost to shorten the time required for inspecting one wafer. In order to increase the throughput, the number of dies that can be inspected at the same time is increased as described above. However, it is necessary to increase the moving speed of the wafer chuck and bring the wafer electrode into contact with the probe. Time also needs to be reduced. However, since the use of the speed reducer as described above makes the moving speed low, it works in the reverse direction to reduce the throughput.

  In addition, a motor that generates high torque has a problem of high cost and large size.

  Thus, an increase in the number of dies that can be simultaneously inspected for high throughput works in the opposite direction that causes a decrease in throughput that lowers the moving speed of the drive motor of the Z moving mechanism.

  An object of the present invention is to improve the throughput by allowing the probe to contact the electrode in the prober in a short time.

  In order to achieve the above object, the prober of the present invention supports the head stage at a plurality of points to adjust the parallelism between the head stage and the wafer chuck surface, and changes the tilt of the head stage relative to the surface of the wafer chuck. Using the stage support mechanism, after the wafer chuck is moved to a predetermined position so that the electrode contacts the probe by the Z movement mechanism, the head stage (probe card) is moved further by the head stage support mechanism. Is realized by moving the wafer relative to the surface of the wafer chuck.

  That is, the prober of the present invention is a prober for connecting a plurality of terminals of the tester to a plurality of electrodes of the device in order to inspect a device formed on the wafer by a tester, and holds the wafer. A wafer chuck, an XY movement mechanism for moving the wafer chuck in the X-axis and Y-axis directions parallel to the surface of the wafer chuck, and the wafer chuck in the Z-axis direction perpendicular to the surface of the wafer chuck A prober comprising: a Z moving mechanism; and a head stage that holds a probe card having a plurality of probes that contact the plurality of electrodes of the device and connect the electrodes to the terminals of the tester, the prober comprising: The head is supported at a plurality of points, and the inclination of the head stage with respect to the surface of the wafer chuck is changed, and the head A head stage support mechanism for moving the stage relative to the surface of the wafer chuck, and when the plurality of electrodes of the wafer held by the wafer chuck are brought into contact with the plurality of probes of the head stage, the XY movement After the electrode is moved by the mechanism so that the electrode is located immediately below the probe, the wafer chuck is moved by the Z moving mechanism to move to a predetermined position where the electrode contacts the probe, and then the head stage support mechanism By moving the head stage, the plurality of probes are brought into contact with the plurality of electrodes with a contact pressure within a predetermined range.

  In the probe contact method of the present invention, in order to inspect a device formed on a wafer with a tester, a plurality of probes of a probe card to which a plurality of terminals of the tester are connected are connected to a plurality of electrodes of the device. A probe contact method for contacting the wafer, wherein the wafer chuck holding the wafer is moved so that the electrode is positioned directly below the probe, and the wafer chuck is moved to a predetermined position where the electrode is in contact with the probe. The head stage holding the probe card is moved so that the plurality of probes come into contact with the plurality of electrodes with a predetermined range of contact pressure.

  Furthermore, the program of the present invention includes a wafer chuck for holding a wafer, an XY movement mechanism for moving the wafer chuck in X and Y axis directions parallel to the surface of the wafer chuck, and the wafer chuck for the wafer. A Z moving mechanism that moves in the Z-axis direction perpendicular to the surface of the chuck, and a plurality of probes that contact the plurality of electrodes of the device formed on the wafer and connect the plurality of electrodes to the plurality of terminals of the tester. A head stage that holds the probe card, and supports the head stage at a plurality of points, changes the inclination of the head stage relative to the surface of the wafer chuck, and moves the head stage relative to the surface of the wafer chuck. Head stage supporting mechanism, the XY moving mechanism, the Z moving mechanism, and the head stage supporting machine A program for operating a computer constituting the movement control unit, wherein the plurality of wafers held by the wafer chuck are held by the plurality of probes of the probe card. When the electrode is brought into contact, the wafer chuck is moved by the XY movement mechanism so that the electrode is located immediately below the probe, and the electrode is brought into contact with the probe by the Z movement mechanism. The wafer stage is moved, and the head stage is moved by the head stage support mechanism so that the plurality of probes come into contact with the plurality of electrodes with a contact pressure within a predetermined range.

  As described above, in the conventional prober, the inclination of the head stage is adjusted and fixed so that the reference surface of the head stage and the mounting surface of the wafer chuck are parallel to each other. Therefore, the tilt of the head stage with respect to the wafer chuck is also fixed. However, as described above, the temperature of the wafer chuck is changed in order to inspect the wafer at a high temperature or low temperature, and the inclination of the head stage and the wafer chuck is minute due to the expansion and contraction of each part caused by the temperature change. There is a big difference. Similarly, when the probe card is replaced with another card, a difference in inclination of the individual difference of the card occurs. In particular, as the wafer size increases in recent years, even a slight difference in tilt between the head stage and the wafer chuck causes a considerable difference in position at both ends of the wafer. There is a problem that a large difference occurs in the contact pressure of the electrodes.

  In order to solve such a problem, the present applicant provides a head stage support mechanism that supports the head stage at a plurality of points and changes the tilt of the head stage relative to the surface of the wafer chuck. We are considering adjusting the degree of parallelism. The amount of movement by this head stage support mechanism is small because it is for tilt adjustment, but the amount of overdrive that further raises the wafer after the electrode contacts the probe is small, so overdrive can be performed with the head stage support mechanism. Is possible.

  The wafer chuck is moved by the XY movement mechanism so that the electrode is located immediately below the probe, and then the wafer chuck is moved to a predetermined position where the electrode contacts the probe by the Z movement mechanism. The predetermined position in this case may be a position where the load applied to the Z moving mechanism, which is a combination of the load generated by the contact between the electrode and the probe and the load of the wafer chuck, is smaller than the load resistance when the Z moving mechanism is moved. The movement up to this point can be performed at high speed even if a low-cost and not high torque motor is used because the load resistance may be small. Next, the head stage is moved by the head stage support mechanism so that the plurality of probes come into contact with the plurality of electrodes with a contact pressure within a predetermined range. This movement needs to have a high torque, but the movement is completed in a short time even at a low speed because the movement distance is short. Therefore, even if the head stage support mechanism uses a speed reducer to move at a high torque, the throughput is hardly reduced.

  According to the present invention, even if a low-cost and low-torque motor is used, the contact operation between the probe and the electrode can be performed in a short time, so that a high-throughput prober can be realized at a low cost.

  The prober according to the embodiment of the present invention has the same configuration as the conventional one shown in FIG. 1, but is provided with a head stage support mechanism for changing the tilt of the head stage 13 and moving the head stage 13 by a small amount. The operation when the electrode is brought into contact with the probe 24 is different.

  FIG. 2 is a diagram illustrating the configuration of the head stage support mechanism.

  As shown in the figure, the head stage 13 is supported at four corners by four head stage support mechanisms. Each head stage support mechanism includes a motor 51 to which a high-precision encoder is attached and whose rotation amount can be precisely controlled, and a reduction gear (gear) 52 that decelerates the rotation output from the motor 51 and converts it into high-torque rotation. The feed screw is rotated by the rotating shaft 53 of the gear 52 and converted into movement in the axial direction, the moving member 55 is moved in the axial direction by the feed screw mechanism 54, and the movement of the moving member 55 is guided. The guide 56 includes a connecting member 58 that connects the tip of the moving member 55 and the corner portion of the head stage. The motor 51, the gear 52, and the guide 56 are fixed to the column 12. A universal joint or the like may be used as the connecting member 58. However, since the moving amount is small here, the connecting member 58 firmly fixes the tip of the moving member 55 and the corner portion of the head stage 13, and four pieces are provided. The head stage 13 moves in parallel when the head stage support mechanism moves by the same amount of movement, but the case including the head stage 13 is distorted when the amount of movement differs, but there is no problem because the amount of movement is small. .

  In FIG. 2, the column 12 extends in a direction perpendicular to the paper surface, and two head stage support mechanisms are attached to the same column 12. In FIG. 2, the interval between the columns 12 needs to be a distance that allows the wafer chuck 21 to move at least the diameter of the wafer W, that is, a distance that is twice or more the diameter of the wafer chuck 21. Also, an alignment camera (not shown) is provided at a portion away from the probe card 23 in a direction perpendicular to the paper surface of FIG. 2, and the wafer chuck 21 is moved below to perform an alignment operation. 21 can move a distance longer than the above distance in a direction perpendicular to the paper surface of FIG.

  The four motors 51 of the head stage support mechanism are driven by a head stage motor driver 61, and the head stage motor driver 61 is controlled by a control signal H from the movement control unit 62. The movement control unit 62 is realized by a computer or the like, and outputs movement control signals such as an XY movement mechanism and a Z / θ mechanism.

  Next, the probe contact operation in the prober of the embodiment of the present invention will be described based on the flowchart of FIG.

  It is assumed that the head stage tilt is adjusted by the head stage support mechanism so that the tip of the probe 24 and the surface of the wafer chuck 21 are parallel before starting the probe contact operation. Further, when the wafer W to be inspected is placed on the wafer chuck 21, an alignment operation or the like is performed, the positional relationship between the electrode of the wafer W and the probe 24 is obtained, and the wafer chuck 21 is rotated by the Z · θ mechanism unit 20. Thus, it is assumed that the arrangement of the electrodes on the wafer W and the arrangement of the probes 24 are adjusted to coincide.

  In step 101, the wafer chuck 21 is moved by the XY moving mechanism so that the electrode to be contacted is located immediately below the corresponding probe 24.

  In step 102, movement of the wafer chuck 21 in the Z direction by the Z · θ mechanism, that is, raising of the wafer chuck 21 is started.

  In step 103, when the wafer chuck 21 reaches a predetermined position in the Z direction, the movement in the Z direction is stopped. The movement in the Z direction is performed so as to reach a predetermined position by further moving the first overdrive amount after the probe 24 contacts the wafer W. The first overdrive amount is appropriately set in a range in which the load due to the contact between the probe and the electrode does not exceed the load resistance when the Z moving mechanism moves. The amount of movement in this case is determined from the height of the wafer surface detected by the alignment camera and the probe camera and the tip of the probe 24, but is detected by the Z moving mechanism after detecting that the probe 24 has contacted the wafer W. You may make it move to Z direction only by fixed quantity.

  The movement from step 101 to step 103 can be performed at high speed without the need for significant deceleration with gears because no load is applied due to contact between the probe and the electrode.

  In step 104, the head stage 13 starts moving the head stage 13 in the Z direction, that is, lowering the head stage 13 by the head stage support mechanism.

  In step 105, the movement is stopped when the head stage 13 moves to a predetermined position in the Z direction.

  The amount of movement in steps 104 and 105 is a second overdrive amount obtained by subtracting the first overdrive amount from the desired overdrive amount after the electrode contacts the probe. The movements in steps 104 and 105 are low-speed movements, but are completed in a short time because the movement amount is very small.

  As mentioned above, although the Example of this invention was described, it cannot be overemphasized that various modifications are possible. For example, although the feed screw mechanism is used as the head stage support mechanism in the embodiment, it can also be realized by a moving mechanism using a piezo element. Moreover, you may implement | achieve the connection part of a head stage support mechanism with a universal joint.

  The present invention is applicable to any prober as long as it is a prober.

It is a figure which shows schematic structure of the wafer test system which test | inspects the chip | tip on a wafer with a prober and a tester. It is a figure which shows the structure of the head stage support mechanism of the prober of the Example of this invention. It is a flowchart which shows the probe contact operation | movement in the prober of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Base member 12 Support | pillar 13 Head stage 22 Card holder 23 Probe card 24 Probe 30 Tester 51 Motor 52 Gear 54 Feed screw mechanism 56 Guide 57 Connecting member W Wafer

Claims (3)

A prober for connecting a plurality of terminals of the tester to a plurality of electrodes of the device in order to inspect the device formed on the wafer by a tester,
A wafer chuck for holding the wafer;
An XY movement mechanism for moving the wafer chuck in the X-axis and Y-axis directions parallel to the surface of the wafer chuck;
A Z movement mechanism for moving the wafer chuck in a Z-axis direction perpendicular to the surface of the wafer chuck;
A head stage holding a probe card having a plurality of probes that contact a plurality of electrodes of the device and connect the electrodes to terminals of the tester;
A prober comprising:
A head stage support mechanism for supporting the head stage at a plurality of points, changing the inclination of the head stage relative to the surface of the wafer chuck, and moving the head stage relative to the surface of the wafer chuck;
When the plurality of electrodes of the wafer held by the wafer chuck are brought into contact with the plurality of probes of the probe card, the XY movement mechanism moves the electrodes so that the electrodes are located immediately below the probes, The wafer chuck is moved by a Z movement mechanism to move the electrode to a predetermined position where it contacts the probe, and then the head stage is moved by the head stage support mechanism, so that the plurality of probes become the plurality of electrodes. A prober that makes contact with a contact pressure within a predetermined range. A probe contact method for contacting a plurality of probes of a probe card, to which a plurality of terminals of the tester are connected, with a plurality of electrodes of the device, in order to inspect the device formed on the wafer with a tester,
Move the wafer chuck holding the wafer so that the electrode is located directly under the probe,
Moving the wafer chuck to a predetermined position where the electrode contacts the probe;
The probe contact method, wherein the head stage is moved so that the plurality of probes come into contact with the plurality of electrodes with a contact pressure within a predetermined range. A wafer chuck for holding a wafer, an XY movement mechanism for moving the wafer chuck in the X-axis and Y-axis directions parallel to the surface of the wafer chuck, and a Z-axis perpendicular to the surface of the wafer chuck Head stage for holding a probe card having a plurality of probes that contact a plurality of electrodes of a device formed on a wafer and connect the plurality of electrodes to a plurality of terminals of a tester And a head stage support mechanism that supports the head stage at a plurality of points, changes the inclination of the head stage relative to the surface of the wafer chuck, and moves the head stage relative to the surface of the wafer chuck; An XY movement mechanism, a Z movement mechanism, and a movement control unit for controlling the head stage support mechanism. In that prober, a program for operating the computer constituting the moving control unit,
When contacting the plurality of electrodes of the wafer held by the wafer chuck to the plurality of probes of the probe card,
The wafer chuck is moved by the XY moving mechanism so that the electrode is located immediately below the probe,
By the Z moving mechanism, the wafer chuck is moved to a predetermined position where the electrode contacts the probe,
A program characterized in that the head stage is moved by the head stage support mechanism so that the plurality of probes are in contact with the plurality of electrodes with a contact pressure within a predetermined range.

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