JP5504546B1 - Prober - Google Patents

Abstract

Provided is a prober for performing high-frequency measurement and wafer level inspection of dynamic characteristics with high accuracy on a wafer on which a plurality of chips having electrodes on both sides are formed.
A wafer chuck having a conductive support surface a holding a wafer W having electrodes on both sides and capable of contacting the back electrode of the chip, a moving rotation mechanism for moving and rotating the wafer chuck 18, and a chip A head stage 22 holding a probe card 24 having a probe 25 for contacting the surface electrode and connecting the surface electrode to a terminal of the tester body 31 is formed in parallel with and electrically connected to the support surface 18a. A stage member 50 having a conductive stage surface 50a that can move integrally with the wafer chuck 18, and a spring that is fixed at a position facing the stage member 50 and whose tip is in electrical contact with the stage surface 50a. A pin 52 is provided, and the back electrode of the chip is electrically connected to the tester body 31 via the spring pin 52.
[Selection] Figure 1

Description

  The present invention relates to a prober that performs electrical inspection of a plurality of chips 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 by a wafer test system composed of a prober and a tester. The prober fixes the wafer to the wafer chuck and brings the probe into contact with the electrode of each chip. The tester is electrically connected to the probe, and measures the characteristics by applying current and voltage to each chip for electrical inspection.

  Semiconductor devices (devices) such as power transistors, power MOSFETs (field effect transistors), IGBTs (insulated gate bipolar transistors), LEDs, and semiconductor lasers generally have electrodes (chip surface electrodes) formed on the surface of a wafer. An electrode (chip back electrode) is also formed on the back surface of the wafer. For example, in an IGBT, a gate electrode and an emitter electrode are formed on the front surface of a wafer, and a collector electrode is formed on the back surface of the wafer.

  In order to perform wafer level inspection on a wafer in which a plurality of chips having electrodes are formed on both surfaces of the wafer as described above, the wafer chuck holds the back surface of the wafer in contact and acts as a measurement electrode for the tester. A supporting surface (wafer mounting surface) is provided. This support surface is electrically connected to the tester via a cable drawn from the wafer chuck. When inspection is performed, various measurements are performed in a state where the wafer is held on the wafer chuck and the probe is in contact with the electrode (chip surface electrode) of each chip formed on the surface of the wafer. Yes.

  However, since the cable connecting the wafer chuck and the tester is arranged in a state of being routed inside and outside the housing via a connection connector provided on the side surface or the back surface of the housing constituting the prober. The length is usually about 1 to 3m. For this reason, the electrical path formed between the chip back electrode and the tester becomes longer, and the resistance and inductance increase, resulting in measurement errors in high frequency measurement and dynamic measurement, and wafer level inspection with the required accuracy. There is a problem that cannot be performed properly.

  On the other hand, in Patent Document 1, in order to solve the above problem, a chuck lead plate provided so as to face the conductive support surface of the wafer chuck, a pogo pin fixed to the peripheral portion of the wafer chuck, An inspection device comprising a is described. According to this inspection apparatus, since the electrical path formed between the chip back electrode and the tester is configured via the pogo pin and the chuck lead plate, the electrical path is generated in the electrical path as compared with the conventional configuration described above. Resistance and inductance can be reduced.

JP2011-138865A

  However, in the inspection apparatus described in Patent Document 1, since the pogo pins are fixed to the wafer chuck, the length of the electrical path between the chip back electrode and the tester varies depending on the position of the chip to be inspected on the wafer. . For example, the length of the electrical path is different between the case of inspecting a chip existing near the center of the wafer and the case of inspecting a chip existing near the edge of the wafer. For this reason, the resistance and impedance generated in the electrical path change depending on the position of the chip to be inspected on the wafer, which adversely affects high frequency measurement and dynamic measurement, and the wafer level inspection cannot be performed with high accuracy. There is a problem.

  The present invention has been made in view of such circumstances, and provides a prober capable of performing high-frequency measurement and wafer level inspection of dynamic characteristics with high accuracy on a wafer on which a plurality of chips having electrodes on both sides are formed. The purpose is to do.

In order to achieve the above object, a prober of the present invention holds a wafer on which a plurality of chips having electrodes on both sides are formed, and has a wafer chuck having a conductive support surface capable of contacting the back electrode of the chip, and a wafer A moving and rotating mechanism for moving and rotating the chuck, a head stage for holding a probe holding unit having a probe for contacting the surface electrode of the chip and connecting the surface electrode to the terminal of the tester for electrically inspecting the chip; A conductive stage surface formed in parallel to the support surface and electrically connected to the support surface, and a stage member movable integrally with the wafer chuck, and fixed at a position facing the stage member And a contact that can be electrically contacted with the front end of the stage surface, and the back electrode of the chip is tested via the wafer chuck, the stage member, and the contact. To be electrically connected, said stage member, said wafer chuck is constructed by separated, the support surface and the stage surface is Ru are electrically connected through a wiring member.

  In a preferred aspect of the present invention, the stage member is configured such that the contact can always contact the stage surface when the probe contacts the surface electrode of the chip within the movable range of the wafer chuck.

  Moreover, the preferable aspect of this invention WHEREIN: A contact consists of a spring pin.

  In a preferred embodiment of the present invention, the contact comprises a probe card-like contact.

  In a preferred aspect of the present invention, the contact is fixed to the head stage or the probe holding unit.

  Moreover, the preferable aspect of this invention is arrange | positioned as a contactor group which a contactor consists of a some contactor which adjoins mutually, and a contactor group is arrange | positioned at predetermined intervals.

  According to the present invention, since the resistance and impedance in the electrical path formed between the chip back electrode and the tester are small and less fluctuating, high-frequency measurement and dynamic measurement can be performed stably, and wafer level inspection is performed. Can be performed with high accuracy.

The figure which shows schematic structure of the wafer test system of embodiment of this invention. Plan view showing wafer chuck and stage member The figure which shows the position change on the wafer of the chip to be inspected, and the position change of the spring pin Explanatory drawing of a 1st modification Explanatory drawing of a 1st modification Explanatory drawing of a 2nd modification Explanatory drawing of a 4th modification

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a schematic configuration of a wafer test system according to an embodiment of the present invention. As shown in the figure, the wafer test system includes a prober 10 for contacting the probe to the electrode of each chip on the wafer and an electrical connection to the probe for applying current and voltage to each chip for electrical inspection. And a tester 30 for measuring the characteristics.

  The prober 10 includes a base 11, a moving base 12 provided on the base 11, a Y-axis moving base 13, an X-axis moving base 14, a Z-axis moving / rotating unit 15, a wafer chuck 18, and wafer alignment. The camera 19 includes support columns 20 and 21, a head stage 22, a card holder 23 provided on the head stage 22, and a probe card 24 to which the card holder 23 is attached. A probe 25 is provided on the probe card 24.

  The movement base 12, the Y-axis movement table 13, the X-axis movement table 14, and the Z-axis movement / rotation unit 15 constitute a movement / rotation mechanism that rotates the wafer chuck 18 in the three axis directions and around the Z axis. Since the moving / rotating mechanism is widely known, the description thereof is omitted here.

  The probe card 24 has a probe 25 arranged according to the electrode arrangement of the device to be inspected, and is exchanged according to the device to be inspected. A needle alignment camera for detecting the position of the probe and a cleaning mechanism for cleaning the probe are provided, but are omitted here.

  The tester 30 includes a tester body 31 and a contact ring 32 provided on the tester body 31. The probe card 24 is provided with a terminal connected to each probe 25, 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).

  The wafer chuck 18 has a conductive support surface (wafer mounting surface) 18 a that holds the back surface of the wafer W in contact with the wafer W and acts as a measurement electrode of the tester 30.

  In the present embodiment, in addition to the above-described configuration, a stage member 50 provided on the side of the wafer chuck 18 and a plurality of spring pins 52 fixed to the head stage 22 at a position facing the stage member 50, It is configured with.

  The stage member 50 is fixed to a side portion of the wafer chuck 18 and is configured to be movable integrally with the wafer chuck 18. The stage member 50 has a conductive stage surface 52a with which each spring pin 52 can come into contact. The stage surface 50 a is configured to be parallel and flush with the support surface 18 a of the wafer chuck 18 and is electrically connected to the support surface 18 a of the wafer chuck 18. The stage surface 50a may not be flush with the support surface 18a as long as the spring pin 52 can always come into contact with the probe 25 when contacting the chip surface electrode of the wafer W.

  FIG. 2 is a plan view showing the stage member 50 and the wafer chuck 18. As shown in the figure, the stage member 50 is formed in a large shape having a larger area than the wafer chuck 18, and has a convex portion 50 b that is curved outward and a concave portion that is curved inward. 50c and connecting portions 50d and 50e that connect the two. The connecting portions 50d and 50e are formed in parallel with each other and have the same width as the outer diameter of the wafer chuck 18. The concave portion 50c has a shape that matches the outer shape (semicircular arc shape) of the side portion of the wafer chuck 18. Then, the stage member 50 is integrated with the wafer chuck 18 by bonding the two in a state where the concave portion 50c of the stage member 50 is in close contact with the side portion of the wafer chuck 18.

  Although not shown, the contact surface between the stage member 50 and the wafer chuck 18 also serves as an electrical connection portion, and the stage surface 50a of the stage member 50 and the support surface 18a of the wafer chuck 18 are connected via this electrical connection portion. Between the two is secured.

  Returning to FIG. 1, a plurality of spring pins 52 that can come into contact with the stage surface 50 a of the stage member 50 are provided on the lower surface 22 a of the head stage 22 (opposite surface of the stage member 50). In this example, four spring pins 52 are provided. Each spring pin 52 is formed of a thin conductive needle having spring characteristics. When the wafer chuck 18 is raised and the probe 25 comes into contact with the chip surface electrode of the wafer W, the spring pin 52 contacts the stage surface 50a of the stage member 50. Each spring pin 52 is configured to contact at a predetermined contact pressure. In FIG. 2, reference numeral 60 indicates a contact position on the stage surface 50a on the stage member 50 with which the spring pin 52 contacts. Reference numeral 62 indicates the position of the chip on the wafer W with which the probe 25 contacts.

  On the upper surface 22 b of the head stage 22, a connector portion 54 connected in common to each spring pin 52 is provided. One end of a cable 56 is connected to the connector portion 54, and the other end of the cable 56 is connected to a connector portion 58 of the tester body 31. Thereby, the chip back surface electrode formed on the back surface of the wafer W is electrically connected to the tester body 31 via the wafer chuck 18, the stage member 50, the spring pin 52, the connector portion 54, the cable 56, and the connector portion 58. Connected.

  When performing the inspection, the tip position of the probe 25 is detected by a needle alignment camera (not shown). Next, in a state where the wafer W is held on the wafer chuck 18, the wafer chuck 18 is moved so that the wafer W is positioned under the wafer alignment camera 19, and the chip electrodes (chip surface electrodes) on the wafer W are moved. Detect position. It is not necessary to detect the positions of all the electrodes of one chip, and the positions of several electrodes may be detected. Further, it is not necessary to detect the electrodes of all the chips on the wafer W, and the positions of the electrodes of several chips are detected.

  After detecting the position of the probe 25 and the position of the chip electrode on the wafer W, the wafer chuck 18 is rotated by the Z-axis moving / rotating unit 15 so that the arrangement direction of the chip electrode coincides with the arrangement direction of the probe 25. To do. Then, after moving so that the electrode of the chip to be inspected on the wafer W is positioned below the probe 25, the wafer chuck 18 is raised and the electrode of the chip is brought into contact with the probe 25. At this time, the stage member 50 fixed to the side portion of the wafer chuck 18 is also raised together, and each spring pin 52 comes into contact with the stage surface 50 a of the stage member 50. Thereby, the chip back surface electrode formed on the back surface of the wafer W is electrically connected to the tester body 31 via the wafer chuck 18, the stage member 50, and the spring pins 52. Then, current and voltage are applied to the chip from the tester body 31 to measure the characteristics.

  When the inspection of this chip is completed, the wafer W and the probe 25 are once separated, and other chips move so as to be positioned under the probe 25, and the same operation is performed. Hereinafter, each chip is selected and inspected. When the inspection of all the designated chips on the wafer is completed, the inspection of one wafer is completed.

  FIG. 3 is a diagram showing the relative positional relationship between the position of the chip to be inspected on the wafer W and the spring pin 52. FIGS. 3A to 3E show cases in which the center, left end, right end, upper end, and lower end chips on the wafer W are inspected, respectively. As described above, the wafer chuck 18 moves so that the electrode (chip surface electrode) of the chip to be inspected on the wafer W is positioned below the probe 25. On the other hand, since the spring pin 52 is fixed to the head stage 22, even if the wafer chuck 18 moves, the relative positional relationship between the probe 25 and the spring pin 52 does not change. For this reason, even if the position 62 of the chip to be inspected on the wafer W changes, the distance L from the position 62 to the position 60 on the stage member 50 with which the spring pin 52 contacts is always constant.

  As described above, according to the present embodiment, the chip back surface electrode is connected to the tester body 31 via the wafer chuck 18, the stage member 50, and the spring pin 52 regardless of the position of the chip to be inspected on the wafer W. The length of the electrical path is always constant. For this reason, since resistance and impedance in the electrical path are small and have little fluctuation, high-frequency measurement and dynamic measurement can be stably performed, and wafer level inspection can be performed with high accuracy.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the scope of the present invention. . Hereinafter, some modified examples will be described.

[Modification 1]
In the above-described embodiment, the configuration in which the stage member 50 is fixed while being in close contact with the side portion of the wafer chuck 18 has been described. However, for example, as illustrated in FIG. 4, the wafer chuck 18 and the stage member 50 are configured separately. May be. In this case, the support surface 18 a of the wafer chuck 18 and the stage surface 50 a of the stage member 50 are electrically connected via a plurality of wires 64. The stage member 50 is connected to the moving / rotating mechanism of the wafer chuck 18 by a connecting member (not shown), and is configured to be movable integrally with the wafer chuck 18.

  The stage member 50 is not particularly limited as long as the spring pin 52 is always in contact with the stage member 50 in a movable range, and may be configured in a circular shape as shown in FIG. 5, for example. In this case, similarly to the configuration shown in FIG. 4, the support surface 18a of the wafer chuck 18 and the stage surface 50a of the stage member 50 are electrically connected via a plurality of wirings 64, and the stage member 50 is connected to the wafer chuck. 18 is configured to be movable together.

[Modification 2]
In the above-described embodiment, the configuration in which the spring pin 52 is provided on the head stage 22 that constitutes the housing of the prober 10 is shown. However, the spring pin 52 may be provided on a member held by the head stage 22. For example, as shown in FIG. 6, the probe card 24 may be provided with a spring pin 52. In this case, the spring pin 52 is electrically connected to the tester body 31 through the contact ring 32. Thereby, even if the wafer chuck 18 moves, the relative positional relationship between the spring pin 52 and the probe 25 does not change, so that the same effect as the above-described embodiment can be obtained.

[Modification 3]
In the embodiment described above, the spring pin 52 is preferably used as a contact (conduction pin) that can contact the stage surface 50a of the stage member 50. However, a probe card-like contact such as a cantilever type or a vertical needle type is used. Also good.

[Modification 4]
In the above-described embodiment, the head stage 22 is configured to be provided with a contact group composed of a plurality of spring pins 52 in a state of being close to each other. However, the head stage 22 is in contact with a plurality of locations at predetermined intervals. It is good also as a structure which provided the child group. For example, in the example shown in FIG. 7, the head stage 22 (only part of which is shown) is provided with two attachment positions 68A and 68B at a predetermined interval, and each of the attachment positions 68A and 68B has eight springs. A contact group consisting of pins 52 is arranged. As described above, according to the configuration in which the contact groups are provided at a plurality of locations, the stage member 50 can be downsized as compared with the configuration in which the contact groups are provided at one location.

[Modification 5]
In the embodiment described above, the configuration including the probe card 24 is shown, but the present invention may be applied to a probe head type that does not include the probe card 24. That is, the probe holding unit held by the head stage 22 is not limited to the probe card 24 but may be a manipulator type probe head or the like.

  DESCRIPTION OF SYMBOLS 10 ... Prober, 11 ... Base, 12 ... Base member, 13 ... Y-axis moving table, 14 ... X-axis moving table, 15 ... Z-axis moving / rotating part, 18 ... Wafer chuck, 18a ... Support surface, 19 ... Alignment Camera, 20, 21 ... post, 22 ... head stage, 23 ... card holder, 24 ... probe card, 25 ... probe, 30 ... tester, 31 ... tester body, 32 ... contact ring, 50 ... stage member, 50a ... stage surface

Claims (7)

A wafer chuck that holds a wafer on which a plurality of chips having electrodes on both sides are formed and has a conductive support surface that can contact the back electrode of the chip;
A moving rotation mechanism for moving and rotating the wafer chuck;
In order to electrically inspect the chip, a head stage that holds a probe holding unit having a probe that contacts a surface electrode of the chip and connects the surface electrode to a terminal of a tester;
A conductive stage surface formed in parallel to the support surface and electrically connected to the support surface, and a stage member movable integrally with the wafer chuck;
A contactor disposed at a position facing the stage member and having a tip electrically contactable with the stage surface;
The back electrode of the chip is electrically connected to the tester via the wafer chuck, the stage member, and the contact.
The stage member, said wafer chuck is constructed by separated, the support surface and the stage surface characteristics and to pulp rover to be electrically coupled via a wire member.   The said stage member is comprised so that the said contactor can always contact the said stage surface when the said probe contacts the surface electrode of the said chip | tip within the movable range of the said wafer chuck | zipper. Prober. The contactor is prober according to claim 1 or 2, characterized in that it consists of a spring pin. The prober according to any one of claims 1 to 3 , wherein the contactor comprises a probe card-like contactor. The contactor is prober according to any one of claims 1 to 4, characterized in that fixed to the head stage. The contactor is prober according to any one of claims 1 to 5, characterized in that fixed to the probe holder. The said contactor is arrange | positioned as a contactor group which consists of a some contactor which adjoins mutually, The said contactor group is arrange | positioned at predetermined intervals, The any one of Claims 1-6 characterized by the above-mentioned. The prober described in 1.

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