JP2007095753A - Prober, prober contact method, and program therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prober wherein a defect (contact mark) due to contact with the electrode pad of a probe is limited within the electrode pad. <P>SOLUTION: The prober includes a probe guard 25 with a probe to touch an electrode, a wafer stage 18, movement mechanisms 12-17 of the wafer stage, and a movement control unit 27 to control the movement mechanism. The control unit controls the movement mechanisms in a manner that, when the electrode of a semiconductor device is brought into contact with a probe 26, the electrode thereof may be moved just beneath the probe 26, and the wafer stage 18 may be moved to the movement completion position toward the probe in a first direction so as to bring the electrode into contact with the probe 26. The control unit can control the movement mechanism so that the wafer stage may be moved at an optional speed in the first direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a prober, a probe contact method, and a program for connecting a die electrode to a tester in order to electrically inspect 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 stage 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 basic configuration of a system for inspecting chips on a wafer using a prober and a tester. As shown, the prober 10 includes a base 11, a moving base 12, a Y-axis moving table 13, an X-axis moving table 14, a Z-axis moving unit 15, and a Z-axis moving table provided thereon. 16, θ rotation unit 17, wafer stage 18, needle alignment camera 19 that detects the position of the probe, side plates 20 and 21, head stage 22, and support means (not shown) are supported on the base 11. The wafer alignment camera 23, the card holder 24 provided on the head stage 22, the probe card 25 attached to the card holder 24, and a stage movement control unit 27. The probe card 25 is provided with a cantilever type probe 26. The movement base 12, the Y-axis movement table 13, the X-axis movement table 14, the Z-axis movement unit 15, the Z-axis movement table 16, and the θ rotation unit 17 move the wafer stage 18 in the three-axis direction and the Z-axis. A movement / rotation mechanism that rotates as a center is configured and controlled by the stage movement control unit 27. Since the moving / rotating mechanism is widely known, the description thereof is omitted here. The probe card 25 has a probe 26 arranged according to the electrode arrangement of the device to be inspected, and is exchanged according to the device to be inspected.

  The tester 30 includes a tester body 31 and a contact ring 32 provided on the tester body 31. The probe card 25 is provided with a terminal connected to each probe, and the contact ring 32 has a spring probe arranged so as to contact the terminal. The tester body 31 is held with respect to the prober 10 by a support mechanism (not shown).

  When the inspection is performed, the Z-axis moving table 16 is moved so that the needle alignment camera 19 is positioned below the probe 26, and the tip position of the probe 26 is detected by the needle alignment camera 19. The detection of the tip position of the probe 26 must be performed whenever the probe card is replaced, and is appropriately performed every time a predetermined number of chips are measured even when the probe card is not replaced. Next, with the wafer W to be inspected held on the wafer stage 18, the Z-axis moving table 16 is moved so that the wafer W is positioned under the wafer alignment camera 23, and the electrode pads of the semiconductor chips on the wafer W are moved. The position of is detected. It is not necessary to detect the positions of all the electrode pads of one chip, and the positions of several electrode pads may be detected. Further, it is not necessary to detect the electrode pads of all the chips on the wafer W, and the positions of the electrode pads of several chips are detected.

  FIG. 2 is a diagram for explaining the operation of bringing the electrode pad into contact with the probe 26. After detecting the position of the probe 26 and the position of the wafer W, the θ stage 17 rotates the wafer stage 18 so that the arrangement direction of the chip electrode pads coincides with the arrangement direction of the probe 26. Then, after moving so that the electrode pad of the chip to be inspected on the wafer W is positioned below the probe 26, the wafer stage 18 is raised and the electrode pad is brought into contact with the probe 26.

  When the electrode pad is brought into contact with the cantilever type probe 26, the electrode pad is moved from a height position (contact start position) at which the surface of the electrode pad contacts the tip of the probe 26 to a position higher by a predetermined amount (movement end position). Raise. The contact start position is detected by the needle alignment camera 19. The movement end position is determined by the amount of displacement of the tip of the probe at which the bending amount of the cantilever type probe 26 is obtained so as to obtain a contact pressure that realizes reliable electrical contact between the probe 26 and the electrode pad. The height position in addition to the position. Actually, the number of probes 26 is several hundred, for example, and the movement end position is set so that reliable electrical contact is realized between all the probes 26 and the electrode pads.

  A semiconductor manufacturing apparatus such as a prober is required to have a high throughput, and it is required to perform an operation of bringing the electrode pad into contact with the probe 26 as described above at a high speed. Therefore, after the electrode pad of the chip of the wafer W is positioned under the probe 26, the speed when the wafer stage 18 is raised is also high, and the stage movement control unit 27 controls to stop accurately at the movement end position. is doing.

JP 2004-039752 A (Overall)

  2. Description of the Related Art In recent years, semiconductor devices (devices) have been increasingly miniaturized, and accordingly, the size of electrode pads has been reduced, and the electrode pads themselves have been rapidly reduced in thickness. In addition, a material having a low hardness has been used for the electrode pad. Further, multilayering of semiconductor devices has been promoted, and an electric circuit has been formed under an electrode pad.

  With conventional electrode pads, normal contact was established even when the probe was brought into contact with the electrode pad by the above method. However, due to the thinning of the electrode pad and the use of a low hardness material as described above. However, when the probe is brought into contact with the electrode pad by a conventional method, there is a problem that the tip of the probe penetrates the electrode pad film and normal contact cannot be established. In addition, when an electric circuit is formed under the electrode pad, if the tip of the probe penetrates the electrode pad film, the electric circuit under the electrode pad is damaged and does not operate normally.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and an object of the present invention is to make a scratch (contact trace) due to contact of an electrode pad of a probe within the electrode pad.

  In order to achieve the above object, a prober, a probe contact method for bringing a probe into contact with an electrode, and a program for the prober move the wafer stage at a plurality of different speeds.

  That is, the prober of the present invention is a prober for connecting each terminal of the tester to the electrode of the semiconductor device in order to inspect the semiconductor device formed on the wafer by the tester, and to the electrode of the semiconductor device. A probe card having a probe that contacts and connects the electrode to a terminal of the tester; a wafer stage that holds a wafer; a moving mechanism that moves the wafer stage; and a movement control unit that controls the moving mechanism; And when the electrode of the semiconductor device is brought into contact with the probe, the control unit moves so that the electrode of the semiconductor device is located immediately below the probe, and then the electrode comes into contact with the probe. A prober that controls the moving mechanism to move the wafer stage in the first direction to the movement end position with respect to the probe. Te, the control unit is characterized by the movement of the first direction of the wafer stage is controllable said moving mechanism to move at any speed.

  As described above, in the conventional prober, the speed when the wafer stage is raised after the electrode pad of the wafer is positioned under the probe is high. Therefore, even when stopping at the movement end position, the relative speed when the electrode pad first contacts the prober at the contact start position is high, and the electrode pad collides with the probe at high speed. This is the cause of the tip of the probe penetrating the electrode pad film. Therefore, in the prober of the present invention, the movement of the wafer stage in the first direction (Z direction) can be controlled to move at an arbitrary speed so that the relative speed when the electrode pad contacts the prober can be reduced. To.

  However, if the movement of the wafer stage in the Z direction is slow, there is a problem that the throughput is lowered. Therefore, the wafer stage is moved at a high speed with respect to the probe to the low-speed movement start position before the movement end position, and is moved at a low speed from the low-speed movement start position to the movement end position, thereby minimizing a decrease in throughput. Limit to the limit. At that time, it is desirable to stop at the low-speed movement start position and then move to the movement end position at low speed.

  Since the height position of the tip of the probe is measured in advance by the needle alignment camera, the contact start position where the electrode first contacts the probe is known in advance. Therefore, by temporarily stopping the wafer stage at the contact start position between the low-speed movement start position and the movement end position, the collision speed when the electrode first contacts the probe can be made very low. it can.

  Further, after the electrode comes into contact with the probe, the wafer stage moves up while the electrode is in contact with the probe, so there is no collision. Therefore, even if the movement speed from the contact start position to the movement end position is made faster than the movement speed from the low-speed movement start position to the contact start position, no problem occurs and the throughput is improved.

  However, when the collision speed of the electrode pad with the probe decreases, the contact trace becomes shallow and the damage of the electrode pad is reduced, but the electrical contact resistance value does not sufficiently decrease as the contact trace becomes shallow, There is a possibility of causing a problem that good conduction cannot be obtained. Therefore, during the movement from the contact start position where the electrode pad comes into contact with the probe to the movement end position, the electrode pad moves once in the reverse direction and then moves again toward the movement end position without deepening the contact trace. It is desirable to improve the contact condition to obtain better conduction.

  It is desirable that the low-speed movement start position, the movement end position, the movement speed between each position, and the like can be appropriately set according to the specifications of the semiconductor device (device). It can be easily realized.

  Here, the probe card provided with the probe is fixed and the wafer held on the wafer stage moves, but the wafer held on the wafer stage is fixed and the probe card provided with the probe is fixed. The present invention can also be applied to the case of movement, and movement means relative movement.

  According to the present invention, even when the electrode pad is made of a thin and low hardness material and a circuit is provided under the electrode pad, the probe penetrates the electrode pad when the electrode pad is brought into contact with the probe. And the yield can be improved by reducing the occurrence of defective chips during inspection.

  Examples of the present invention will be described below. The embodiment of the present invention has the same configuration as the conventional prober described in FIGS. 1 and 2, and only the movement control method in the Z-axis direction by the stage movement control unit 27 when the electrode pad is brought into contact with the probe. Suppose they are different. The stage movement control unit 27 is realized by a computer, and the above control method is realized by changing a computer program. Accordingly, only the movement control in the Z-axis direction of the stage when the electrode pad is brought into contact with the probe will be described here, and other description will be omitted.

  In the embodiment of the present invention, the stage movement control unit 27 can control the moving speed in five steps, and can control the acceleration / deceleration in five steps. The reversal operation is also possible.

  FIG. 3A is a diagram for explaining the movement of the stage in the Z-axis direction when the electrode pad is brought into contact with the probe in the embodiment. In the figure, the horizontal axis indicates the position in the Z direction, and the position indicated by zero (0) is the height position of the distal end portion of the probe 26 detected by the needle alignment camera 19, and is referred to here as the contact start position. . The electrode pad is raised to a movement end position (position +50 in the figure) 50 μm higher than the contact start position and stopped. Below the contact start position (negative Z position in the figure), the electrode pad does not contact the probe. This area is called a clearance area, and above the contact start position (positive Z position in the figure), the electrode pad is the probe. This region is called a contact region. The solid line indicates the speed at the time of movement, and the broken line indicates the maximum movement speed in each change, and control is performed so that the maximum movement speed is not exceeded in each region. The movement is actually controlled by the wafer stage, and the above position is determined by adding the thickness of the wafer to the position of the upper surface of the wafer stage.

  As shown in FIG. 3A, the maximum movement speed is set at a high level in a region below a predetermined amount below the contact start position (−50 position) (low speed movement start position). In the region above the low-speed movement start position, the maximum movement speed is set to a low level. In the area below the low-speed movement start position, when the movement is started, the speed is increased to the highest level of the maximum movement speed, and after maintaining the maximum movement speed, the vehicle is decelerated so as to stop once at the low-speed movement start position. Thereafter, the speed is increased to a low level maximum movement speed, and after maintaining the maximum movement speed, the vehicle is decelerated so as to stop once at the contact start position. The speed is again increased to a lower level maximum movement speed, and after maintaining the maximum movement speed, the vehicle is decelerated so as to stop at the movement end position.

  As described above, since the tip of the probe is located in the vicinity of the contact start position, the speed when the electrode pad collides with the probe is below the maximum moving speed at a low level, particularly in FIG. Since the vehicle is accelerated after being decelerated so as to stop once near the contact start position, the collision speed is very small. Therefore, the tip of the probe does not penetrate the electrode pad film.

  When the electrode pad is separated from the probe, it is not necessary to perform the above-described control, and it may be moved downward at a high level maximum moving speed.

  FIG. 3B is a diagram for explaining a modification of the above embodiment. As shown in the drawing, in the modification of FIG. 3B, the operation until stopping once at the low-speed movement start position is the same as that of FIG. After stopping once at the low-speed movement start position, the speed is increased to a low level maximum movement speed, and after maintaining the maximum movement speed, the vehicle is decelerated so as to stop once at the contact start position. Next, the speed is increased to an intermediate level maximum movement speed higher than the low level maximum movement speed, and after maintaining the maximum movement speed, the vehicle is decelerated to stop at the movement end position. As a result, the movement time is slightly shortened and the throughput is improved.

  Also in the modified example of FIG. 3B, since the vehicle is accelerated after being decelerated so as to temporarily stop near the contact start position, the collision speed is very low. After the electrode pad comes into contact with the probe, the electrode pad is raised while in contact with the probe, so there is no impact due to collision, and even if the moving speed is slightly high, the impact on the electrode pad is small and no problem occurs.

  FIG. 4 is a diagram for explaining still another modification of the above embodiment. As shown in the figure, in the modified example of FIG. 4, the operation until stopping once at the low-speed movement start position is the same as (A) of FIG. After stopping once at the low-speed movement start position, the speed is increased to a low level maximum movement speed, and after maintaining the maximum movement speed, the vehicle is decelerated to stop once before the contact start position. Next, the speed is increased to the maximum moving speed in the reverse direction at a low level so as to move in the descending direction, and then decelerated to stop once after a while. Then, the speed is increased to a lower maximum moving speed so as to rise again, and after maintaining the highest moving speed, the speed is decelerated so as to stop once before the contact start position. This reduces throughput, but provides good continuity between the probe and the electrode pad without damaging the electrode pad, since the collision is only performed once at a low speed.

  In the modification of FIG. 4, an example in which the movement in the reverse direction is performed only once is shown, but it may be performed twice or more.

  Since the speed at which the electrode pad collides with the probe is reduced, not only the electrode pad is damaged, but also the damage to the probe is reduced, so that there is an advantage that the life of the probe is extended.

  The present invention can be applied to any prober as long as it is a prober. For example, the same effect can be obtained even when a probe card using a spring probe is used instead of a cantilever probe.

It is a figure which shows the basic composition of the system which test | inspects the chip | tip on a wafer with a prober and a tester. It is a figure explaining the operation | movement which makes an electrode pad contact a probe. In an Example, it is a figure explaining the movement of the Z-axis direction of a stage when making an electrode pad contact a probe. In an Example, it is a figure explaining the movement of the Z-axis direction of a stage when making an electrode pad contact a probe.

Explanation of symbols

18 Wafer stage 19 Needle alignment camera 23 Wafer alignment camera 25 Probe card 26 Probe

Claims (14)

A prober for connecting each terminal of the tester to an electrode of the semiconductor device in order to inspect the semiconductor device formed on the wafer by a tester,
A probe card having a probe that contacts the electrode of the semiconductor device and connects the electrode to a terminal of the tester;
A wafer stage for holding the wafer;
A moving mechanism for moving the wafer stage;
A movement control unit for controlling the movement mechanism,
When the electrode of the semiconductor device is brought into contact with the probe, the controller moves so that the electrode of the semiconductor device is positioned immediately below the probe, and then the wafer stage is brought into contact with the probe. A prober for controlling the moving mechanism to move the probe in the first direction to the movement end position with respect to the probe;
The prober, wherein the control unit is capable of controlling the moving mechanism so as to move the wafer stage in the first direction at an arbitrary speed.   The control unit moves the wafer stage with respect to the probe at a high speed to a low-speed movement start position before the movement end position and moves at a low speed from the low-speed movement start position to the movement end position. The prober according to claim 1, wherein the prober controls the moving mechanism.   3. The prober according to claim 2, wherein the control unit controls the moving mechanism so that the wafer stage is temporarily stopped at the low-speed movement start position and then moved to the movement end position at a low speed.   4. The prober according to claim 3, wherein the control unit controls the moving mechanism so that the wafer stage is temporarily stopped at a contact start position between the low-speed movement start position and the movement end position.   The said control part controls the said moving mechanism so that the moving speed from the said contact start position to the said movement end position may be made faster than the moving speed from the said low-speed movement start position to the said contact start position. The described prober.   5. The control unit according to claim 4, wherein the control unit controls the moving mechanism so as to move once in the reverse direction from the contact start position to the movement end position and then move toward the movement end position again. 6. Prober. A probe contact method for contacting a probe of a prober with an electrode of a semiconductor device formed on a wafer,
When the wafer stage is moved in the first direction with respect to the probe to the movement end position so that the electrode contacts the probe after the electrode of the semiconductor device moves so as to be positioned immediately below the probe. ,
The method according to claim 1, wherein the movement of the wafer stage in the first direction can be performed at an arbitrary speed.   8. The wafer stage according to claim 7, wherein the wafer stage is moved at a high speed with respect to the probe to a low-speed movement start position before the movement end position, and is moved at a low speed from the low-speed movement start position to the movement end position. Method.   The method according to claim 8, wherein the wafer stage is temporarily stopped at the low-speed movement start position and then moved to the movement end position at a low speed.   The method according to claim 9, wherein the wafer stage is temporarily stopped at a contact start position between the low-speed movement start position and the movement end position.   The method according to claim 10, wherein a movement speed from the contact start position to the movement end position is higher than a movement speed from the low-speed movement start position to the contact start position.   The method according to claim 10, wherein the method once moves in a reverse direction from the contact start position to the movement end position and then moves again toward the movement end position. A program for controlling a prober to control a prober probe to come into contact with an electrode of a semiconductor device formed on a wafer,
When the wafer stage is moved in the first direction with respect to the probe to the movement end position so that the electrode contacts the probe after the electrode of the semiconductor device moves so as to be positioned immediately below the probe. ,
A program characterized in that the movement of the wafer stage in the first direction can be moved at an arbitrary speed.   The program according to claim 13, wherein the wafer stage is moved at a high speed with respect to the probe to a low-speed movement start position before the movement end position, and is moved at a low speed from the low-speed movement start position to the movement end position. .

Images