JP4563751B2 - Manufacturing method of probe needle - Google Patents

Description

  The present invention relates to a probe card mainly used in an inspection process in a manufacturing process of a semiconductor device, and more particularly to a probe needle used in the probe card.

  In recent years, with the high integration and miniaturization of semiconductor devices, the distance between bonding pads or inspection pads has become narrower and the number of pads has increased. As a result, the probe needles mounted on the probe card are also densely packed. In addition, since a plurality of semiconductor devices are inspected at the same time in order to reduce the inspection cost, the number of probe needles mounted on one probe card is further increased and the density is increased. In such a situation, adjacent probe needles influence each other during inspection, and noise such as crosstalk is generated. Therefore, there is a need for a probe needle that can suppress the influence of noise without reducing the density.

  A probe card having cantilever type probe needles has a large number of probe needles arranged radially on a substrate. The proximal end of each probe needle is soldered onto the substrate, and the distal end is held in a state where it is lifted from the substrate by the distal position fixing member. Then, the tip of each probe needle is pressed against the pad of the semiconductor device at the center of the probe needle group located radially, and the device is inspected.

  In such a probe card, when the number of probe needles increases, adjacent probe needles influence each other, and it becomes easy to pick up noise such as crosstalk. Further, in a probe card that simultaneously inspects a plurality of semiconductor devices, probe needles may be arranged close to each other in the vertical direction, and noise is easily picked up.

Therefore, due to such noise, the inspection accuracy is lowered, or a re-inspection is required, resulting in an increase in inspection time.
In order to reduce the influence of noise caused by such probe needles, a probe card using a coaxial probe needle has been proposed. In this probe needle having a coaxial structure, an intermediate portion of a central conductor is covered with an insulating tube, and the periphery thereof is covered with an outer conductor made of a conductive metal tube.

By connecting both end portions of the outer conductor to the ground wiring on the substrate, the outer conductor acts as a shield layer, so that the influence of noise can be reduced.
Patent Documents 1 and 2 disclose a probe card using a coaxial probe needle.
JP-A-8-22463 Japanese Patent Laid-Open No. 2-50452

  In the conventional probe needle having the coaxial structure as described above, the diameter of the central conductor is 130 μm or more, and usually 150 μm. When covered with an insulating tube, the diameter becomes 170 μm, and when covered with an external conductor, the diameter increases by about 200 μm. Accordingly, the diameter of the coaxial needle is twice or more than that of a normal probe needle covered with an insulating tube.

Therefore, not all probe needles can have a coaxial structure, and the probe needles having a coaxial structure have been used only for a part requiring noise countermeasures.
However, since the diameter of such a coaxial needle is large, it is necessary to secure a larger interval than the normal needle interval, and the force for pressing the pad is different from the normal probe needle due to the difference in the diameter, so the needle trace is Management becomes complicated.

  In addition, since the probe needle of the coaxial structure is greatly different from the diameter of the normal probe needle, it cannot be attached to the probe card with the same needle standing rule as the normal probe needle, and it is necessary to use a different rule. . Therefore, there is a problem that the assembly work of the probe card becomes complicated.

  An object of the present invention is to provide a probe needle capable of easily assembling a probe card while having a coaxial configuration capable of reducing the influence of noise.

The above object is a method of manufacturing a probe needle in which a central conductor is covered with an insulating tube, and a conductive layer is formed around the insulating tube to form a coaxial structure, wherein the conductive layer is a first mixed with a conductive material. The central conductor is immersed in the solvent, then drawn out from the solvent and dried, and the central conductor is immersed in the first solvent leaving one end of the insulating tube, and after drying, the other end of the central conductor is formed. This is achieved by a method for manufacturing a probe needle in which the conductive layer of the part is removed with a second solvent to expose the other end of the insulating tube .

  ADVANTAGE OF THE INVENTION According to this invention, the probe needle which can assemble a probe card easily can be provided, although it is the coaxial structure which can reduce the influence of noise.

(First embodiment)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the probe card shown in FIGS. 1 and 2, a large number of probe needles 2 are radially arranged on a disc-shaped substrate 1 from the center of the substrate 1 toward the outer periphery.

  The proximal end portion of each probe needle 2 is soldered to the needle stand portion 3 of the substrate 1, and the distal end portion is held by a fixing member 4 made of synthetic resin at the center portion of the substrate 1. Accordingly, each probe needle 2 has a cantilever structure in which the distal end portion is closely packed in the central portion of the substrate 1 and rises from the substrate toward the distal end from the proximal end.

  A specific configuration of the probe needle 2 and a manufacturing method thereof will be described with reference to FIG. The center conductor 5 of the probe needle 2 shown in FIG. 3A is made of tungsten and has a diameter of 130 μm. Further, the tip is shaped so as to taper toward the tip.

Next, as shown in FIG. 2B, the intermediate portion of the center conductor 5 is covered with an insulating tube 6. By covering with the insulating tube 6, the diameter becomes 150 μm.
Next, as shown in FIG. 2C, the central conductor 5 is immersed in the solvent L, leaving the insulating tube 6 on the tip side slightly. This solvent L is a one-part room-temperature-curing silver-based material obtained by kneading and dispersing fine flaky silver powder, which is a conductive material, with a high polymer acrylic resin as a binder together with a solvent such as ethyl acetate or butyl acetate. It is a conductive adhesive.

  Thereafter, as shown in FIG. 4D, the central conductor 5 is taken out of the solvent and dried to form a conductive layer 7 having a film pressure of 10 μm so as to cover the insulating tube 6. This film pressure can be adjusted by the temperature of the solvent, the viscosity of the solvent based on the composition (ratio) of the conductive material and the solvent, the pulling speed from the solvent, and the temperature and humidity in the drying process.

  Next, as shown in FIG. 5E, the base end portion of the central conductor 5 is immersed in the solvent M not mixed with the conductive material to remove the conductive layer 7, and as shown in FIG. The proximal insulating tube 6 is exposed. By such a process, the probe needle 2 having a coaxial configuration is formed, and the diameter thereof is 170 μm.

  In order to mount the probe needle 2 thus configured on the substrate 1, as shown in FIG. 4, the tip of the probe needle 2 is attached to the fixing member 4, and the fixing member 4 is attached to the substrate 1. To do. Then, the proximal end of the probe needle 2 is soldered to the substrate 1 and both ends of the conductive layer 7 are connected to the ground wiring 8 on the substrate 1 by soldering or a conductive adhesive.

  The ground wiring 8 is extended to the vicinity of the front end side of the conductive layer 7 by sticking a copper foil from the through hole 9 in the center of the substrate 1 to the side surface of the fixing member 4. The tip is connected.

The following effects can be obtained by the probe needle manufacturing method as described above.
(1) The probe needle 2 having a coaxial structure can be formed with a diameter substantially equal to that of a normal probe needle covered with an insulating tube 6.
(2) Since the probe needle 2 having a coaxial structure can be formed with a diameter almost equal to that of a normal probe needle, all the probe needles can be coaxial needles.
(3) Since all the probe needles mounted on the substrate can be coaxial needles, a probe card that is less susceptible to noise can be formed.
(4) Since the probe needle 2 having the coaxial structure can be formed with a diameter substantially equal to that of the normal probe needle, the coaxial needle can be mounted on the substrate according to the same rule as the normal needle stand rule. Accordingly, the probe card can be easily assembled.
(Second embodiment)
FIG. 5 shows a second embodiment. In this embodiment, the diameter of the probe needle 2 is reduced by reducing the diameter of the central conductor 5 at the portion covered with the insulating tube 6.

  That is, the portion covered with the insulating tube 6 is the reduced diameter portion 10. The reduced diameter portion 10 is formed with a diameter 20 μm smaller than other portions of the central conductor 5 if the thickness of the conductive layer 7 is 10 μm as in the first embodiment.

  By adopting such a configuration, the diameter after being covered with the insulating tube 6 and the conductive layer 7 becomes equivalent to that of a conventional probe needle covered only with the insulating tube 6. Therefore, the probe card can be assembled with the same needle stand rule as that of the conventional probe needle.

Further, since the diameter of the portion fixed by the fixing member 4 and the diameter of the tip portion are not changed, durability, needle pressure, contactability, etc. equivalent to those of the conventional probe needle can be obtained.
The above embodiment may be modified as follows.
-The conductive material is fine particles of low melting point alloy such as copper, copper alloy, silver, nickel, solder, metal oxide fine particles such as zinc oxide and inbidium oxide, various carbon black, conductive polymer particles such as polypyrrole and polyaniline, Polymer fine particles coated with metal, copper or silver fine particles coated with noble metal, metal fibers, carbon fibers, and the like may be used. In addition, tin, lead, zinc, iron, phosphorus, silicon, chromium, bismuth, cadmium, titanium, magnesium, aluminum, arsenic, antimony, molybdenum, cobalt, and the like may be used.
The conductive layer 7 may be formed by applying a solvent mixed with a conductive material around the insulating tube 6 and then drying it.
The conductive layer 7 may be formed by laminating a conductive material around the insulating tube 6 by vapor deposition.

It is sectional drawing which shows the probe card of 1st embodiment. It is a top view which shows a probe card. (A)-(f) is explanatory drawing which shows the manufacturing process of a probe needle. It is sectional drawing which shows a probe card. It is sectional drawing which shows the probe needle of 2nd embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Probe needle 5 Center conductor 6 Insulation tube 7 Conductive layer

Claims (1)

A method of manufacturing a probe needle in which a central conductor is covered with an insulating tube and a conductive layer is formed around the insulating tube to form a coaxial structure.
The conductive layer is formed by immersing the central conductor in a first solvent mixed with a conductive material, and then pulling out from the solvent and drying.
The central conductor is immersed in the first solvent leaving one end of the insulating tube, and after drying, the conductive layer at the other end of the central conductor is removed with a second solvent, and the other end of the insulating tube A method for manufacturing a probe needle, wherein the probe needle is exposed.

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