JP2000230938A - Contact probe equiped with tungsten needle and probe device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make adjustable a characteristic impedance with use of a tungsten needle, and reduce external noises and signal losses at high frequencies. SOLUTION: Base parts 6b... of a plurality of tungsten needles 6... are soldered to electrodes of a printed board. Middle parts are fixed to a holding part 16 and leading end parts 6a are curved. A double-layer film 20 is applied via an adhesive from each of the base parts 6b... of the tungsten needles 6... to the holding part 16, thereby constituting a contact probe 14. The double-layer film 20 is comprised of an insulating resin film 22 and a grounded metallic film 24 of a good conductivity. The contact probe 14 constitutes a microstrip line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a contact probe and a probe device used for performing an electrical test by contacting each terminal of a member to be inspected such as a semiconductor IC chip, an LSI chip, a liquid crystal device or the like.

[0002]

2. Description of the Related Art In general, a probe device having a contact probe mounted on a printed circuit board in order to conduct an electrical test of a semiconductor chip such as an IC chip or an LSI chip, or a member to be inspected such as an LCD (liquid crystal display). Is used. As an example of such a probe device, there is one using a tungsten needle (hereinafter, referred to as a tungsten needle) as a contact probe as shown in FIGS. 7 and 8, for example. In the probe device 1, the printed circuit board 2 has a substantially disk shape, for example, and an opening 3
Are formed. The device surface 4 which is one surface of the printed circuit board 1 has, for example, approximately 9
Contact probes 5A, 5B, 5 in four directions at 0 ° intervals
C and 5D are provided and face each other at the opening 3. A plurality of tungsten needles 6 are arranged in each of the contact probes 5A to 5D, and a base 6b as one end thereof is connected to an electrode of a pattern wiring (not shown) of the printed circuit board 2 by soldering or the like. .., Which are the other ends, protrude into the opening 3 in plan view as contact pins, and are brought into contact with terminals of a member to be inspected such as an IC chip during an electrical test. Moreover, the plurality of tungsten needles 6 of each of the contact probes 5A to 5D are
They are arranged in a substantially fan shape so that the distance between them gradually decreases from the base 6b toward the tip 6a.

As shown in FIG. 8, each of the tungsten needles 6 extends from the base 6b toward the tip 6a.
Of the device surface 4 and is fixed at an inclined position at a predetermined angle by a holding portion 7 made of resin attached near the opening 3 of the device surface 4. Further, a ring-shaped metal plate 9 for reinforcement is attached to a connection surface 8 for connection with a tester on the opposite side of the device surface 4 of the printed circuit board 2 by screws or the like, and is disposed around the opening 3. Has been established.

[0004]

By the way, high-speed processing is required in accordance with high integration and miniaturization of IC chips and the like. However, a contact probe of a tungsten needle has a long transmission line and adjusts characteristic impedance. However, there is a disadvantage that reflection noise occurs at a point where the impedance is not uniform. In this case, there is a problem in that the longer the transmission lines having different characteristic impedances are, the larger the reflected noise is generated. The reflected noise becomes a signal distortion and becomes liable to cause a malfunction at a high frequency. For this reason, in the case of a tungsten needle, if the frequency of the transmission signal increases, the loss of the signal increases, making transmission difficult, and there is a disadvantage that the function as a high-frequency transmission line is not sufficiently satisfied.

In view of such circumstances, the present invention provides a contact probe and a probe device capable of adjusting characteristic impedance by using a tungsten needle to reduce external noise and signal loss at high frequencies. The purpose is to do.

[0006]

A contact probe according to the present invention is characterized in that a film provided with a dielectric layer and a metal layer is applied to a plurality of tungsten needles, and the tips of the tungsten needles protrude from the film. And The contact probe according to the present invention constitutes a microstrip line using a tungsten needle. Further, the contact probe according to the present invention is configured such that a plurality of tungsten needles are coated with a dielectric layer and a metal layer to form respective coaxial lines, and the tip of the tungsten needle projects from the dielectric layer and the metal layer. Features.

Therefore, according to the present invention, the tungsten needle can be used as a contact probe and the metal layer can be used as ground, and the characteristic impedance can be adjusted by the thickness of the dielectric layer between the tungsten needle and the metal layer. Noise can be reduced, and signal loss at high frequencies can be reduced. These contact probes have a high-frequency transmission path structure.

In a probe device according to the present invention, a plurality of tungsten needles are connected to a wiring substrate on which a pattern wiring is formed, and a film provided with a dielectric layer and a metal layer on the surface of the tungsten needles is adhered. The tip of the tungsten needle is projected from the film. The film may also be applied to a soldered portion between the tungsten needle and the electrode of the wiring substrate. Since the soldered portion is particularly noisy, it is effective to reduce the noise of the soldered portion by the ground metal layer.

In the probe apparatus according to the present invention, a coaxial line covered with a dielectric layer and a metal layer is connected to a plurality of tungsten needles, respectively, on a wiring substrate on which a pattern wiring is formed. The tip of the needle protrudes from the dielectric layer and the metal layer.

In the present invention, by using the metal layer as the ground, it is possible to design impedance matching up to the vicinity of the tip of the tungsten needle, and it is possible to prevent adverse effects due to reflected noise even when performing a test in a high frequency range. . That is, if the characteristic impedance between the wiring pattern of the wiring board and the tip of the tungsten needle does not match in the middle of the transmission line from a tester called a prober, reflected noise occurs, and in that case, transmission lines having different characteristic impedances are generated. There is a problem that as the length is longer, a larger reflected noise is generated. Reflected noise causes signal distortion, and tends to cause signal degradation at high frequencies. In the present invention, by using the metal layer as the ground, it is possible to suppress the deviation of the characteristic impedance from the wiring pattern of the wiring substrate up to the vicinity of the tip of the tungsten needle, and to suppress the deterioration of the signal due to the reflection noise.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, in which the same reference numerals are used for the same parts or members as those in the above-mentioned prior art. 1 to 3 relate to the first embodiment, FIG. 1 is a longitudinal sectional view of a probe device according to the embodiment, FIG. 2 is a plan view showing a device surface of the probe device shown in FIG. 1, and FIG. FIG. 3 is a partial perspective view of a contact probe of the probe device shown in FIGS. 1 and 2. In the probe device 12 shown in FIGS. 1 and 2, the printed circuit board 2 (wiring board) has a disk shape made of, for example, glass epoxy resin, and one surface of the printed circuit board 2 is the device surface 4 and the other surface is the opposite side. Is a connecting surface 8 with the tester. A substantially rectangular opening 3 is formed in the center of the printed circuit board 2, for example. A wiring pattern (not shown) is provided on the device surface 4 from the periphery of the opening 3 toward the outer periphery, and is provided on the connection surface 8 via a conductive member inserted in the thickness direction of the printed circuit board 2. The electrode is connected to an electrode (not shown) for connection with the tester.

On the device surface 4, contact probes 14 in which a plurality of tungsten needles 6 are arranged are arranged, for example, in four directions substantially orthogonal to each other, and are contact probes 14A, 14B, 14C, and 14D, respectively. . For example, in the contact probe 14A, the bases 6b of the tungsten needles 6 are connected and fixed as soldering portions to electrode terminals of a wiring pattern (not shown) on the device surface 4 by soldering or the like, and the tungsten needles 6 face the other end. Direction to gradually separate from device surface 4 (downward in FIG. 1)
The tip portion 6a projects into the opening 3 in plan view. The tip portion 6a of the tungsten needle 6 is formed to be curved downward in, for example, a substantially L-shape or a substantially arc shape (see FIGS. 1 and 3), and is a member to be inspected at the time of an overdrive scrub. An aluminum oxide film on the surface of a terminal such as a pad of an IC chip is scraped off so that electrical contact can be reliably made. As shown in FIG. 3, the tip 6a has a tip edge converging in a conical shape, and the top thereof forms a small circular plane 6a-1. It can be identified with an optical microscope or the like.

On the device surface 4, a substantially rectangular cylindrical first holding frame 16 made of an appropriate resin material is formed so as to surround the opening 3 so as to surround the opening 3. A tungsten needle 6 is attached to the corner of the tip of the first holding frame 16.
Are held in contact with each other. A second holding frame 17 is further provided at the tip of the first holding frame 16 with which the tungsten needles 6 abut, and the first and second holding frames 16,
Reference numeral 17 denotes a holding portion 18 for holding and fixing the tungsten needles 6. The first and second holding frames 16 and 17 are made of, for example, an insulating resin member.

Moreover, in the contact probe 14A, a large number of tungsten needles 6 which are held in the above-described posture and are arranged in a substantially fan shape so as to gradually increase the distance from the tip 6a toward the base 6b are provided. As shown in FIGS. 2 and 3, the two-layer film 2 is interposed with an insulating adhesive.
0 is attached. This two-layer film 20
Are an insulating resin film 22 (dielectric layer) made of, for example, a polyimide resin and adhered to the plurality of tungsten needles 6 via an adhesive layer, and a metal film 24 (metal layer) forming a grounded ground layer. ). The two-layer film 20 is formed so as to cover from the bases 6b of the tungsten needles 6 to the holding frame 18 which are soldered portions to the electrodes of the wiring pattern. Therefore, the contact probe 14A forms a high-frequency transmission path structure of a microstrip line. Other contact probes 14
B, 14C, and 14D have the same configuration and are incorporated in the probe device 12, respectively.

Contact probe 1 according to the present embodiment
Since the probe 4 and the probe device 12 are configured as described above, the metal film 24 can be used as a ground by attaching the two-layer film 20 to the tungsten needles 6. The deviation of the characteristic impedance from the wiring pattern of the printed circuit board 2 can be minimized, and the deterioration of the signal due to the reflection noise can be suppressed, and the high frequency can be supported. In addition, since the two-layer film 20 is disposed up to the base 6b, which is the soldering portion of the tungsten needle 6, the deterioration of the signal due to the reflection noise is suppressed even in the soldering portion where the reflection noise is large, so that it is possible to cope with a high frequency. Has the effect of The resin film 22 between the tungsten needle 6 and the metal film 24
It is possible to adjust the characteristic impedance by the thickness of the substrate, thereby reducing external noise and loss of signals at high frequencies.

In the above-described embodiment, when disposing the two-layer film 20 on the tungsten needles 6, the base 6b of each tungsten needle 6 is soldered to the printed circuit board 2 and the tip 6a is held in the holding portion 18. In the state fixed with, the tungsten needles 6 from the holding portion 18 to the base 6b are provided.
The two-layer film 20 is applied to the surface opposite to the printed circuit board 2 of FIG.
As shown in the figure, a two-layer film 20 may be provided on the surface of the tungsten needle 6 on the printed circuit board 2 side. In this case, the two-layer film 20 may be applied to the soldering portion of the base 6b as in the above-described embodiment. Alternatively, attaching the two-layer film 20 on the base 6b may be omitted.

Next, a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. The same reference numerals are used for the same or similar members as those in the above-described first embodiment, and the description is given. Omitted. FIG. 5 is a partial perspective view showing a coaxial line including one tungsten needle of the contact probe according to the second embodiment, and FIG. 6 is a main part of a probe device equipped with the contact probe having the coaxial line shown in FIG. It is a longitudinal cross-sectional view. In the contact probe 30 according to the second embodiment shown in FIG.
A resin layer 34 (dielectric layer) made of a resin that is an insulator, for example, a polyimide resin is coated over the entire circumference to be formed, for example, in a ring shape in cross section.
A grounded ground layer 36 (metal layer) made of a highly conductive metal such as u, Ni or the like is formed over the entire circumference, for example, in a ring shape in cross section, and these constitute a coaxial line 38.
The contact probe 30 has a high-frequency transmission structure. The coaxial line 38 has a distal end 38a and a proximal end 38b.
Then, the resin layer 34 and the ground layer 36 are cut off, and the tungsten needle 6 is exposed. The tip 38a of the tungsten needle 6 is curved in a substantially arc shape and converges on the top surface 6a-1 of the small circle in a substantially conical shape. And a proximal end 38b.
Is a base 6b (soldering portion) at which the tungsten needle 6 is soldered to the electrode of the wiring pattern of the printed circuit board 2.

The plurality of coaxial lines 38 are connected to a probe device 40 shown in FIG. 6 as in the first embodiment.
The contact probe 30 is mounted and arranged on the device surface 4 of the printed circuit board 2. Each coaxial line 3
Reference numeral 8 denotes a soldering portion in which the base 6b of the tungsten needle 6 is soldered to an electrode of a wiring pattern of the printed circuit board 2, and a middle portion is fixed by being held by a holding portion 18 including a first holding frame 16 and a second holding frame 17. Have been. Then, the resin layer 34
The tip 6a exposed from the ground layer 36 is brought into contact with a pad of an IC chip at the time of a test. Note that the soldered portion of the base 6b may be covered as in the first embodiment. As described above, also with the contact probe 30 and the probe device 40 according to the second embodiment, the adjustment of the characteristic impedance is facilitated similarly to the first embodiment, and the signal loss at a high frequency can be reduced. In addition, the influence of external noise can be reduced. Moreover, each coaxial line 38 of the contact probe 30 extends beyond the holding portion 18 to the vicinity of the distal end portion 6a, so that impedance matching can be further improved than in the first embodiment.

Next, an example of a method of manufacturing each coaxial line 38 of the contact probe 30 according to the second embodiment will be described. First, a tungsten wire having a wire diameter of several mm is processed to an appropriate diameter of several μm. Next, a resin layer is formed by coating the surface of the tungsten wire with a resin. On the surface of the resin layer 34, Au,
The ground layer 36 is formed by coating a conductive metal such as Ag or Cu.
Is configured. The coated tungsten wire is cut into a predetermined length together with the resin layer 34 and the metal layer 36 to form the tungsten needle 6, and the resin layer 34 and the ground layer 36 are removed from the tip 6a and the base 6b to expose the tungsten needle 6. ,
The tip 6a is curved and polished to sharpen the tip. Thus, the coaxial line 38 is obtained.

In the above-described example, the ground layer 36 is covered on the resin layer 34 made of resin by electroless plating. However, when the ground layer 36 is formed thick, the ground layer 36 is formed by electroless plating. It is also possible to form a thin metal layer on the surface of the substrate 34 so as to have conductivity, and then to perform electrolytic plating. When coating the ground layer 36 on the resin layer 34, the ground layer 36 may be formed by a dry method such as vacuum evaporation or sputtering without being limited to a plating method, that is, a wet method. The method of sharpening the tip of the tungsten needle 6 is not limited to a mechanical polishing method, but may be a chemical polishing method.

[0021]

As described above, in the contact probe according to the present invention, a film provided with a dielectric layer and a metal layer is attached to a plurality of tungsten needles, and the tips of the tungsten needles protrude from the film. Further, the contact probe according to the present invention is configured such that the dielectric layer and the metal layer are coated on each of the plurality of tungsten needles to form the respective coaxial lines, and the tips of the tungsten needles protrude from the dielectric layer and the metal layer. The metal layer can be used as the ground, and the characteristic impedance can be adjusted by the thickness of the dielectric layer between the tungsten needle and the metal layer, thereby reducing external noise and signal loss at high frequencies.

In the probe device according to the present invention, a plurality of tungsten needles are connected to a wiring substrate on which a pattern wiring is formed, and a film provided with a dielectric layer and a metal layer on the surface of the tungsten needles is adhered. The tip portion of the tungsten needle is exposed from the film, and in the probe device according to the present invention, the dielectric substrate and the metal layer are respectively coated on the plurality of tungsten needles on the wiring substrate on which the pattern wiring is formed. The coaxial lines are connected to each other, and since the tip of the tungsten needle projects from the dielectric layer and the metal layer, the coaxial line is designed to use the metal layer as the ground to perform impedance matching near the tip of the tungsten needle. This makes it possible to prevent adverse effects due to reflected noise even when performing a test in a high frequency range.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a probe device according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a device surface of the probe device shown in FIG.

FIG. 3 is a partial perspective view of a contact probe.

FIG. 4 is a longitudinal sectional view showing a modification of the contact probe according to the first embodiment.

FIG. 5 is a perspective view of a main part showing a coaxial line of a contact probe according to a second embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a probe device equipped with a contact probe according to a second embodiment.

FIG. 7 is a plan view showing a device surface of a probe device equipped with a contact probe having a tungsten needle.

8 is a longitudinal sectional view of the probe device shown in FIG.

[Explanation of symbols]

Reference Signs List 2 Printed circuit board (wiring board) 6 Tungsten needle 6a Tip 12 Probe device 14, 14A, 14B, 14C, 14D, 30 Contact probe 20 Two-layer film 22 Resin film (dielectric layer) 24 Metal film (metal layer) 34 Resin layer (dielectric layer) 36 Ground layer (metal layer)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideaki Yoshida 12th Techno Park, Mita City, Hyogo Prefecture Inside the Mita Plant of Mitsubishi Materials Corporation (72) Inventor Naofumi Iwamoto 12th Techno Park, Mita City, Hyogo Prefecture Mitsubishi Materials Corporation Mita Plant F-term (reference) 2G003 AA06 AA07 AE03 AG03 AH00 2G011 AA02 AB06 AB09 AC32 AE03 AE22 4M106 AA02 BA01 BA14 DD03 DD04 DD10 DD11 DD15

Claims (4)

[Claims] 1. A contact probe comprising: a film having a dielectric layer and a metal layer attached to a plurality of tungsten needles; and a tip of the tungsten needle protruding from the film. 2. A wiring substrate on which a pattern wiring is formed, wherein a plurality of tungsten needles are connected, and a film provided with a dielectric layer and a metal layer is applied to the surface of the tungsten needles. A probe device, wherein a tip portion of the probe protrudes from the film. 3. A contact probe comprising: a plurality of tungsten needles each covered with a dielectric layer and a metal layer to form coaxial lines; and a tip of the tungsten needle protruding from the dielectric layer and the metal layer. 4. A wiring substrate on which a pattern wiring is formed, a plurality of tungsten needles each connected to a coaxial line covered with a dielectric layer and a metal layer, and the coaxial line has a tip end of the tungsten needle. A probe device protruding from a dielectric layer and a metal layer.