JP2007165598A - Prober, probe contact method, and program for it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a prober which can make a probe and an electrode pad contact at all times at a desired contact pressure in multi-probing. <P>SOLUTION: The prober to connect the each terminal of a tester to an electrode of a semiconductor device for inspecting a semiconductor device 41 formed on a wafer W by a tester 30 is equipped with a probe card 25 having a probe 26 to contact the electrode, a wafer stage 18, a moving mechanism 12-17, and a movement control portion 27. The movement control unit controls the movement control mechanism so that, after the electrode of the semiconductor device moves so as to be positioned right under the probe, the wafer stage is moved in the first direction to the move end position against the probe so as to make the electrode contact the probe. In the prober, the probe card is provided with a plurality of probes to inspect a plurality of semiconductor devices at the same time, the movement control unit changes the movement end position according to the number of the probe which contacts. <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 wafer test system for inspecting chips on a wafer with 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 for detecting the position of the probe, support columns 20 and 21, head stage 22, and wafer alignment camera provided on a support column (not shown). 23, a card holder 24 provided on the head stage 22, a 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 direction. A movement / rotation mechanism that rotates around 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. The amount of movement from the contact start position to the movement end position is called the overdrive amount.

  Semiconductor manufacturing equipment such as probers require high throughput, and wafer test systems improve inspection throughput by inspecting multiple chips simultaneously with a single contact between a probe and an electrode pad. ing. The process of inspecting a plurality of chips simultaneously is called multi-probing.

  3A shows an example of the arrangement of chips 41 on the wafer W, and FIG. 3B shows an example of the arrangement of chips that are simultaneously inspected in multi-probing. As shown in FIG. 3A, rectangular (or square) chips 41 are arranged on a circular wafer W. As shown in FIG. 3B, in the multi-probing, 11 chips 41 arranged continuously in each row are inspected collectively for every five rows. In other words, 55 chips are tested simultaneously. Here, the range of chips that are simultaneously inspected is referred to as a multi-probing range.

  In order to perform such multi-probing, the probe card 25 is provided with a probe 26 corresponding to the electrode pad of each chip. In recent years, the number of chips to be inspected simultaneously tends to increase. For example, 50 or more chips are inspected at the same time. In that case, when each chip has 50 electrode pads, the probe card 25 is provided with 50 × 55 = 2750 probes.

  In FIG. 3, chips for five rows are alternately inspected every other row, but there are various modifications to the arrangement of chips to be simultaneously inspected. For example, chips in a plurality of consecutive rows may be inspected simultaneously.

  As described above, when the probe is brought into contact with the electrode pad, the probe is moved by the overdrive amount from the contact start position to the movement end position. The probe is bent by the movement of the overdrive amount, and the probe contacts the electrode pad with a predetermined contact pressure. For example, if the desired contact pressure of one probe is 5 g, when there are 2500 probes, the probe card 25 receives a total pressure of 12.5 kg in the central portion as a whole. The probe card is made of a multilayer epoxy resin or the like having a wiring pattern, and bends and deforms upward when it receives a large pressure at the central portion. Such deformation of the probe card substantially reduces the amount of overdrive, and lowers the contact pressure. Therefore, the amount of overdrive is set in anticipation of a decrease in contact pressure due to deformation of the probe card. This overdrive amount is set experimentally using, for example, an actual probe card. All the probes on the probe card are brought into contact with the wafer, and a probe deflection amount corresponding to a desired contact pressure is obtained. It is set to be able to.

JP 2004-039752 A (Overall)

  As shown in FIG. 3A, since the wafer W is circular and each chip 41 is rectangular (or square), the number of chips arranged in each row is different. Further, the number of rows and the number of columns in the chip array is not necessarily an integral multiple of the number of rows and the number of columns in the chip array that are simultaneously inspected by multi-probing. Therefore, when measuring a chip arranged near the center of the wafer W, all the chips within the multi-probing range are inspected at the same time, and all the probes 26 of the probe card 25 come into contact with the electrode pads. When measuring the chips arranged around W, some of the chips in the multi-probing range do not exist, and the probes 26 that do not contact the electrode pads are generated.

  When the number of contacting probes changes, the total contact pressure received by the entire probe card changes accordingly, and the deflection amount of the probe card also changes accordingly. Therefore, as described above, if all probes on the probe card are in contact with each other and the overdrive amount is set, the actual contact pressure will change according to the number of probes that do not contact the electrode pad. Become. However, until now, such a change in the contact pressure has not been particularly taken into account because the influence is small.

  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, electrode pads and materials having low hardness have been used. Further, multilayering of semiconductor devices has been promoted, and an electric circuit has been formed under an electrode pad.

  With conventional electrode pads, the allowable range of contact pressure was large, and normal contact could be established even if the contact pressure varied somewhat. For this reason, when the probe is brought into contact with the electrode pad by a conventional method, a problem has arisen 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.

  Therefore, by making the probe card with a material with little deformation, the difference in deformation due to the difference in the number of contact probes has been reduced, but there is actually no better material than currently used. , Not enough effect. In addition, a reinforcing plate is provided on the probe card to reduce the difference in deformation due to the difference in the number of contact probes, but the reinforcement of the probe card and the head stage that fixes the probe card is also a structural limit, Similarly, sufficient effects are not obtained.

  An object of the present invention is to solve such a problem, and an object of the present invention is to always allow a probe and an electrode pad to contact each other at a desired contact pressure in multi-probing.

  In order to achieve the above object, the prober of the present invention, the probe contact method for bringing a probe into contact with an electrode, and the program therefor include the amount of movement from the contact start position to the movement end position, that is, the amount of overdrive. It changes according to (the number of probes which do not contact).

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 the movement control unit is arranged such that when the electrode of the semiconductor device is brought into contact with the probe, the electrode of the semiconductor device moves so that the electrode is positioned immediately below the probe, and then the electrode comes into contact with the probe. A prober for controlling the moving mechanism so as to move the wafer stage in the first direction to the movement end position with respect to the probe. Oite, the probe card, in order to inspect a plurality of the semiconductor devices at the same time, provided with a plurality of sets of probes for contact with the electrode of the plurality of semiconductor devices,
The movement control unit changes the movement end position according to the number of the probes in contact with the electrodes of the semiconductor device.

  Further, the probe contact method of the present invention is a probe contact method in which a probe provided on a probe card of a prober is brought into contact with an electrode of a semiconductor device formed on a wafer, and the electrode of the semiconductor device is connected to the probe. When the wafer stage holding the wafer is moved in the first direction with respect to the probe to the movement end position so that the electrode comes into contact with the probe after moving so as to be positioned directly below, The movement end position is changed according to the number of the probes in contact with the electrodes.

  The program according to the present invention is a program for causing a computer that controls a prober to control a probe provided on a probe card of the prober so as to contact an electrode of a semiconductor device formed on the wafer. After the electrode of the apparatus has moved so as to be positioned immediately below the probe, the wafer stage holding the wafer is moved in the first direction with respect to the probe to the movement end position so that the electrode contacts the probe. In this case, the movement end position is changed according to the number of the probes in contact with the electrodes of the semiconductor device.

  Specifically, the movement end position is changed by the difference in the deformation amount of the probe card in accordance with the number of probes that are in contact with the electrodes of the semiconductor device.

  The contact pressure of the entire probe card changes according to the number of probes in contact, and the amount of deformation of the probe card also changes accordingly, but according to the present invention, according to the number of probes that contact the overdrive amount, Since the probe card is changed by the difference in deformation amount of the probe card, the contact pressure of the probe can be kept constant even if the number of probes in contact changes.

  According to the present invention, in multi-probing, even when the number of contacting probes changes, the contact pressure of the probes can be kept constant, so that stable contact between the probe and the electrode pad can be established at all times. As a result, 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 and damages the circuit when the electrode pad is brought into contact with the probe. Thus, the generation of defective chips during inspection can be reduced and the yield can be improved.

  Examples of the present invention will be described below. The embodiment of the present invention has the same configuration as the conventional wafer test system and prober described with reference to FIGS. 1 to 3, and the Z axis by the stage movement controller 27 when the electrode pad is brought into contact with the probe during multi-probing. Only the direction movement control method is 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.

  FIG. 4A is a diagram illustrating an example of a multi-probing range 51 that can be simultaneously inspected by one contact when a chip formed on the wafer W is inspected by a multi-probing process. Here, the multi-probing range 51 is shown as being square, but may be rectangular as shown in FIG. 3B, and even if all the chips 41 in the range are inspected at the same time, FIG. You may make it test | inspect every other line. The probe and the electrode pad are contacted while moving each range 51 in the horizontal direction or the vertical direction, and the chips in the range are simultaneously inspected. In the case of inspecting every other line, when the inspection by one contact is completed, the inspection is performed by making contact by shifting by one line. The relationship between the wafer W and the multi-probing array range 51 shown in FIG. 4A is sent from the tester 30 to the stage movement control unit 27 of the prober 10 via a communication path not shown in FIG.

  As shown in FIG. 4A, the four central multi-probing areas are all in the wafer W, and when inspecting each of the four areas, the probes in the multi-probing area (that is, all the probes on the probe card). ) Are all in contact with the electrode pads, but in the other areas, a part of the area is located outside the wafer W, and when inspecting each of these areas, a part of the probe in the multi-probing area, that is, A part of the probe of the probe card is not in contact with the electrode.

  FIG. 4B shows a case where the center chip of the wafer W is inspected. At this time, all the probes in the multi-probing range 51 are in contact with the electrode pads. FIG. 5A shows a case where the chip on the upper side of the wafer W is inspected. At this time, about 80% of the probes in the multi-probing range 51 come into contact with the electrode pads. FIG. 5B shows a case where the chip on the right side of the wafer W is inspected. At this time, about 45 percent of the probes in the multi-probing range 51 come into contact with the electrode pads. As described above, when the number of contacting probes is different, the deformation amount of the probe card is also different.

  FIG. 6 is a diagram showing the relationship between the number of chips to be inspected and the deformation amount of the probe card. (This data is an example when the wafer having the chip arrangement shown in FIG. 3 is inspected by the multi-probing arrangement shown in the figure.) The number of probes contacting the electrode pad is equal to the number of chips to be inspected. Although it is approximately equal to the value multiplied by the number of pads, when inspecting the chip at the periphery of the wafer, there is a probe that contacts the part without the chip. Is small and will be ignored here.

  The data of FIG. 6 shows the probe when the sensor for detecting the displacement of the center of the probe card 25 is provided and the overdrive OD amount is set to 80 μm in the corresponding multi-probing range 51 of FIG. This is a value obtained by detecting the displacement amount at the center of the card 25, and the probe card 25 is deformed in the direction of reducing the contact pressure. As shown in the figure, when 55 chips were inspected simultaneously, that is, when all the probes of the probe card were in contact with the electrode pads, the escape amount of the probe card was 30 μm. When 42 chips were inspected simultaneously, the probe card escape amount was 24 μm, and when 22 chips were inspected simultaneously, the probe card escape amount was 17 μm.

  Considering the probe card escape amount, the substantial overdrive OD amount is a value obtained by subtracting the probe card escape amount from the set OD amount (80 μm), and the substantial OD amount is inspected for 55 chips simultaneously. In this case, the difference is 50 μm, 56 μm when 42 chips are simultaneously inspected, and 63 μm when 22 chips are simultaneously inspected. Therefore, based on the case where 55 chips are inspected simultaneously, the OD amount is 80 μm when inspecting 55 chips simultaneously, and 74 μm when 22 chips are inspected simultaneously, and 22 chips are used. In the case of simultaneous inspection, if the correction is made to 67 μm, the actual OD amount is 50 μm in all cases.

  The stage movement control unit 27 measures and stores in advance the relationship between the number of inspection chips and the card escape amount as shown in FIG. 6, and calculates a correction OD amount according to the position of the multi-probing array with respect to the wafer W. Then, overdrive is performed by the amount of correction OD.

  In addition, since it is necessary to manufacture the probe card for each chip to be inspected, if the wafer diameter is the same, the arrangement of the multi-probing range for the wafer in FIG. 4A is uniquely determined. It is also possible to detect the card escape amount by actually making contact at each array position, and calculate and store the corrected OD amount for each position.

  The present invention can be applied to any type of prober.

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. It is a figure which shows the example of a chip | tip arrangement | sequence on the wafer W, and the example of a chip | tip arrangement | sequence test | inspected simultaneously in multi-probing. In an Example, it is a figure which shows the position in the case of test | inspecting the arrangement | sequence of the range test | inspected simultaneously in the multiprobing with respect to a wafer, and a center chip | tip. In an Example, it is a figure which shows the position in the case of test | inspecting a periphery chip | tip. In an Example, it is a figure which shows the relationship between the chip | tip number to test | inspect and the deformation amount of a probe card.

Explanation of symbols

18 Wafer stage 19 Needle alignment camera 23 Wafer alignment camera 25 Probe card 26 Probe 41 Chip 51 Multi-probing range W Wafer

Claims (6)

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 movement control unit moves so that the electrode of the semiconductor device is positioned immediately below the probe, and then the electrode comes into contact with the probe. In a prober that controls the moving mechanism to move the stage in the first direction to the movement end position with respect to the probe,
The probe card includes a plurality of sets of probes that contact electrodes of a plurality of semiconductor devices in order to simultaneously inspect the plurality of semiconductor devices,
The prober, wherein the movement control unit changes the movement end position in accordance with the number of the probes in contact with the electrodes of the semiconductor device.   2. The prober according to claim 1, wherein the movement control unit changes the movement end position by a difference in deformation amount of the probe card according to the number of the probes contacting the electrodes of the semiconductor device. A probe contact method for contacting a probe provided on a probe card of a prober with an electrode of a semiconductor device formed on a wafer,
After the electrode of the semiconductor device has moved so as to be positioned directly below the probe, the wafer stage holding the wafer is moved in the first direction to the movement end position with respect to the probe so that the electrode contacts the probe. The movement end position is changed in accordance with the number of the probes that are in contact with the electrodes of the semiconductor device when moved to the position.   The method according to claim 3, wherein the movement end position is changed by a difference in deformation amount of the probe card according to the number of the probes contacting the electrode of the semiconductor device. A program for controlling a prober to control a probe provided on a probe card of a prober so as to contact an electrode of a semiconductor device formed on a wafer,
After the electrode of the semiconductor device has moved so as to be positioned directly below the probe, the wafer stage holding the wafer is moved in the first direction to the movement end position with respect to the probe so that the electrode contacts the probe. A program for changing the movement end position in accordance with the number of the probes in contact with the electrodes of the semiconductor device when moving to the position.   The program according to claim 5, wherein the movement end position is changed by a difference in deformation amount of the probe card according to the number of the probes contacting the electrode of the semiconductor device.

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