JP2008045950A - Probe card - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe card that adopts a coaxial structure, readily manufacturable even if positional accuracy of a needle tip is improved, and capable of accurately inspecting a chip device in a high-frequency band, concerning the probe card used for inspection of the electrical characteristics of chip devices that are highly densely integrated on a semiconductor wafer. <P>SOLUTION: This probe card is equipped with a substrate, having a signal wire and a grounding wire, a coaxial cable having a center conductor whose one end is connected to the signal wire and an outside conductor whose one end is connected to the grounding wire, a signal probe bonded to the other end of the center conductor and connected to the signal wire through the center conductor, and a grounding probe bonded to the other end of the outside conductor and connected to the grounding wire through the outside conductor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a probe card used for inspecting electrical characteristics of chips that are densely integrated on a semiconductor wafer, and more particularly to a probe card capable of measurement in a high frequency band.

  As is well known, in a semiconductor device manufacturing process, after a large number of chip devices are formed on a semiconductor wafer, an electrical measurement called a probe test is performed to inspect the electrical characteristics of each chip device. . In this probe test, a probe card having a large number of probes arranged corresponding to the electrode pad arrangement of the chip device formed on the semiconductor wafer is used. The probe card is electrically connected to the tester and transmits a test signal between the tester and the test target chip device by bringing the corresponding probe into contact with each electrode pad of the test target chip device. It is used for.

  Recently, the operation speed of semiconductor devices has been further increased, and in accordance with this, in a probe test, a chip device is inspected using a test signal having a high frequency of several hundred MHz. In the probe test using such a high-frequency signal, for example, two parallel probes shown in FIG. 2a, that is, a signal probe 2 and a grounding probe 3 arranged in parallel at a predetermined interval are used. The aim is to reduce the transmission loss at high frequencies, to reduce the noise entering the transmission signal, and to stabilize the characteristic impedance. The length cannot be shortened, and the frequency band can only be achieved at 400 MHz.

A probe card employing a coaxial line structure apart from the parallel two-line structure is disclosed. As shown in FIG. 2b, the probe card 1 is provided with a coaxial needle 6 and a ground needle (not shown) extending next to the coaxial needle 6, and the outer cover of the coaxial needle 6 is grounded. The probe 2 is provided in contact with the wiring 7-1 and protruding from the outer jacket. The ground needle is joined to the tip of the coaxial needle 6 while the needle is joined to the grounding wiring 7-1. Further, the coaxial needle 6 and the ground needle are bonded and fixed by the intermediate support portion 5. (Reference 1)
JP 2004-309257 A ([0022], [0030], FIG. 3)

  The probe card described above is effective in shortening the portion of the core wire 2 that is not impedance matched with respect to the probe and extending the transmittable frequency to a higher band. However, since the coaxial needle 6 is indirectly fixed by adhering the outer cover thereof with the intermediate support portion 5 on the lower surface of the substrate, the needle tip of the probe 2 is compared with the case where the core wire 2 itself is bonded and fixed. The accuracy of the position becomes worse. Further, a part of the coaxial needle 6 is supported by adhering to the outer jacket by a ground needle extending next to it, but this is also not directly bonded and fixed to the core wire, so it is unlikely that the position accuracy of the needle tip will improve. Further, since the coaxial needle 6 is naturally thicker than the core wire, there is a problem that it is difficult to manufacture a probe card of a coaxial needle corresponding to this when the electrode pitch of the chip device is minimized.

The present invention has been made in order to solve these problems in view of the above circumstances, and is used particularly for high-frequency pulses used for inspection of electrical characteristics of chips integrated on a semiconductor wafer at a high density. The probe card that inspects using waves adopts a coaxial structure, improves the probe part that is not coaxial, and is easy to manufacture even if the needle tip position accuracy is improved. A probe card capable of inspecting a wafer is provided.

  In order to achieve the above object, a probe card according to a first aspect of the present invention includes a substrate having signal wiring and grounding wiring, a central conductor having one end connected to the signal wiring, and one end to the grounding wiring. A coaxial cable having an outer conductor connected thereto, joined to the other end of the central conductor, and connected to the signal probe connected to the signal wiring through the central conductor, and joined to the other end of the outer conductor, A grounding probe connected to the grounding wiring through an outer conductor is provided. Further, the invention of the probe card according to claim 2 is the probe card according to claim 1, wherein the intermediate portion of each of the signal probe and the grounding probe is integrated with the intermediate support portion protruding from the substrate. It is characterized by being fixed to. According to a third aspect of the present invention, there is provided the probe card according to the first or second aspect, wherein the probe card according to the first or second aspect includes a plurality of pairs of the grounding probes spaced apart from each other in parallel by the signal probe and the signal probe. It is characterized by that.

  According to the present invention, a plurality of pairs of signal probes and grounding probes are arranged in such a way that a signal probe that cannot have a coaxial structure from the end in the needle tip direction of the coaxial cable is made into a parallel two-wire structure with a predetermined distance from the grounding probe By disposing, the imperfection of impedance 50Ω matching can be reduced, and the chip device can be inspected under a higher high frequency band. In addition, the needle support for the multiple pairs of signal probes and grounding probes is performed by the intermediate support part, so that the position accuracy of the needle tip can be ensured and the connection with the coaxial cable is facilitated, and the workability becomes easy. This is preferable in manufacturing. In addition, by connecting the grounding probe to the grounding wiring via the outer conductor of the coaxial probe, the grounding circuit can be shortened compared to connecting directly to the grounding wiring, thereby improving transmission characteristics. Becomes better and the frequency band can be expanded.

  According to the probe card according to the first to third aspects of the present invention, a plurality of pairs of signal probes and ground probes are provided, and a system LSI, It is possible to inspect chip devices using a pulse wave in a higher frequency band for LCD drivers and the like, and thus it is possible to sufficiently inspect chip devices compatible with high-speed processing. In addition, it is possible to manufacture because it has a simple structure that ensures the positional accuracy at the needle tips of multiple pairs of signal probes and grounding probes by the intermediate support part and facilitates the connection work with the coaxial cable. It is easy and economical, and the position accuracy of the probe needle tip can be improved and maintained. In addition, since multiple pairs of signal probes and grounding probes have a parallel two-wire structure from the tip of the needle and a certain length can be secured, the probe has a small outer diameter and interval as a probe necessary for inspection of a highly integrated chip. The present invention can be sufficiently applied to a probe card structure having a probe.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a probe card according to an embodiment of the present invention, in which a is a schematic cross-sectional view and b is a cross-sectional view taken along line AA.

  A probe card 1 according to an embodiment of the present invention will be described with reference to FIG. 1. The probe card 1 mainly extends with a plurality of pairs of signal probes 2, ground probes 3, and the signal probes 2. A coaxial cable 6 composed of a central conductor 6-1 and an outer conductor 6-2 that are connected to each other and a dielectric 6-3 interposed therebetween, and a substrate 7 that is in electrical contact with the needle side of the central conductor 6-1. , And grounding wiring 7-1 on the substrate 7 connected to the outer conductor 6-2 of the coaxial cable 6. The grounding probe 3 is disposed in parallel with the signal probe 2 at a predetermined interval, is electrically connected to the end of the coaxial cable 6 on the needle tip side of the outer conductor 6-2, and As described above, the outer conductor 6-2 connects the end portion on the needle side to the ground wiring 7-1. That is, the grounding probe 3 is connected to the grounding wiring 7-1 through the outer conductor 6-2 of the coaxial cable 6.

  Further, as shown in FIGS. 1a and 1b, by arranging the grounding probe 3 below the signal probe 2 (a position far from the substrate), the probe needle tip, that is, from the needle tip to the tip end bending. Since the grounding probe 3 can be made shorter, the impedance characteristics can be further improved, and as a result, the high frequency band can be increased.

  The signal probe 2 and the grounding probe 3 are cantilever type probes made of a conductive metal having springiness and wear resistance, such as a palladium alloy or a rhenium tungsten alloy. The central conductor 6-1 of the coaxial cable 6 uses a good conductor metal such as copper, and the dielectric 6-3 is an insulator having a small relative dielectric constant for reducing transmission loss, that is, a fluorine-based resin such as polytetrafluoroethylene. Resin is used. The outer conductor 6-2 of the coaxial cable 6 is made of a conductive metal, such as copper, aluminum, or an alloy thereof, and is usually in a net shape. Further, instead of connecting the signal probe 2 and the center conductor 6-1 by soldering, the signal probe 2 and the center conductor 6-1 may be integrally formed as a signal probe 2.

  The substrate 7 is a synthetic resin printed board on which the signal wiring 8 connected to the central conductor 6-1 of the coaxial cable 6 connected to the signal probe 2 is provided. (Not shown). In addition, on the lower surface of the substrate 7, a ground wiring 7-1 for connecting the outer conductor 6-2 of the coaxial cable 6 by soldering is disposed. In addition, the grounding probe 3 is connected by soldering to the needle tip side end portion of the outer conductor 6-2 having the cylindrical shape of the coaxial cable 6 and the needle tip side end portion of the outer conductor 6-2. Solder and connect to the ground wiring 7-1. In this way, the grounding probe 3 is connected to the grounding wiring 7-1 via the outer conductor 6-2 of the coaxial cable 6, so that the grounding circuit of the grounding probe 3 can be shortened, and the transmission characteristics can be reduced. Becomes better and the frequency band can be expanded.

  Further, the position accuracy of the needle tips of the grounding probe 3 group which is paired with the signal probe 2 group and the signal probe 2 and spaced in parallel is increased, and each signal probe 2 and the grounding probe are grounded. In order to keep the distance between the probes 3 constant, the intermediate portions of the signal probe 2 group and the grounding probe 3 group are supported and fixed by the intermediate support portion 5. The intermediate support portion 5 includes a support plate 5-1 for accurately positioning the needle tips of the grounding probe 3 group adjacent to the signal probe 2 group, the support plate 5-1, and the probes 2, 3. And a resin fixing part 5-2 for fixing the middle part of the group. The support plate 5-1 is usually made of ceramic and is an annular plate.

  The production of the coaxial portion of the probe card 1 according to the present invention will be described. The needle end side end surface of each signal probe 2 and the needle end side end surface of the central conductor 6-1 of the coaxial cable 6 are connected by soldering. Similarly, the connecting portion 9 is formed by connecting the end surface on the needle base side of each grounding probe 3 and the end surface on the needle tip side of the outer conductor 6-2 of the coaxial cable 6 by soldering. Next, the central conductor 6-1 on the needle base side of the coaxial cable 6 group to which the signal probe 2 group and the ground probe 3 group are connected is connected to the signal wiring 8 at the connection portion 9 by soldering, and the outer conductor. 6-2 is connected to the installation board 7-1 on the board 7 by soldering. In this way, the coaxial cable 6 group is arranged, and the probe card 1 is completed. Further, both the signal probe group 2 and the grounding probe group 3 can be flattened in a fan shape on the needle base side from the intermediate support portion 5, facilitating connection work with the coaxial cable group 6. Can do.

    The operation of the probe card 1 according to the present invention will be described. The signal probe 2 and the grounding probe 3 have a probe length of about 15 mm due to workability and are arranged in a parallel two-line structure. Is a 50Ω coaxial cable 6 having a length of about 15 mm, and is connected to a center conductor 6-1 and an outer conductor 6-2 having a diameter of about 0.15 mm. As described above, the connection from the probe tip to the substrate 7 of the signal probe 2 and the grounding probe 3 is a transmission line configuration of a probe configured by a parallel two-line structure and a coaxial line structure, so that transmission at a high frequency is performed. The loss can be reduced and the characteristic impedance can be stabilized. As a result, the frequency band of the probe card 1 used for inspecting the electrical characteristics of the logic chip devices such as the system LSI and the LCD driver with the pulse wave signal can be increased to about 1.1 GHz. Incidentally, in the case of the probes 2 and 3 having a parallel two-line structure with a needle length of about 30 mm in FIG. 2A, only a frequency band of about 400 MHz could be achieved. Thus, in the probe card according to the present invention, the frequency used for the electrical characteristic inspection of the chip device of the semiconductor wafer can be increased up to about three times.

  In a semiconductor wafer, it can be used for a probe card that uses a signal in a high frequency band, particularly a pulse wave, for inspection of electrical characteristics of a highly integrated chip device.

BRIEF DESCRIPTION OF THE DRAWINGS It is a probe card which is embodiment of this invention, Comprising: a is typical sectional drawing, b is AA arrow sectional drawing. a is a schematic sectional view of a conventional probe card, and b is a schematic sectional view of another conventional probe card.

Explanation of symbols

1: Probe card 2: Signal probe 3: Grounding probe 4: Needle base 5: Intermediate support portion 5-1: Support plate
5-2: Resin fixing part 6: Coaxial cable 6-1: Center conductor 6-2: Outer conductor 6-3: Dielectric 7: Substrate 7-1: Grounding wiring 8: Signaling wiring 9: Connection part

Claims (3)

A substrate having a signal wiring and a ground wiring, a coaxial cable having a central conductor connected at one end to the signal wiring and an outer conductor connected at one end to the ground wiring, and at the other end of the central conductor A signal probe connected to the signal wiring through the central conductor, and a grounding probe connected to the other end of the outer conductor and connected to the ground wiring through the outer conductor. Featured probe card. 2. The probe card according to claim 1, wherein intermediate portions of the signal probe and the ground probe are integrally fixed to the substrate by an intermediate support portion protruding from the substrate. 3. The probe card according to claim 1, further comprising a plurality of pairs of the grounding probes spaced apart from each other by a predetermined interval in parallel with the signal probes.

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