JP2005127952A - Contact probe and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact probe which is fine, accurate and having a good spring property and to provide the contact probe which is easy in an implementation. <P>SOLUTION: The contact probe is used in an inspection probe card and having a cantilever type spring part and a U shape type spring part. And it is characterized that an edge part of the cantilever type spring part and an arm part of the U shape type spring part are oriented in an opposite direction mutually. In the contact probe, the arm part of the U shape type spring part and the edge part of the cantilever type spring part are used for the electrical connection between a conductor electrode of the probe card and an electrode of an object to be tested, and an aspect fixed by one arm part of the U shape type spring part is desirable. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a contact probe for performing an electrical test by contacting an electrode of an electronic component such as a semiconductor IC chip or a liquid crystal device.

  In order to inspect high-density and high-speed electronic components such as LSI, a probe card having a large number of contact probes is used. In the inspection, the contact probe is pressed against the electrode of the electronic component, and various data of the electronic component is collected through the contact probe. Therefore, a reliable contact with the electrode of the electronic component to be inspected is obtained, and the contact probe needs a spring function so as not to damage the electrode.

  As electronic components are highly integrated and increased in speed, contact probes formed corresponding to the electrodes of the electronic components are also integrated. For this reason, in the conventional probe card, a contact probe of 20 to 80 pins / piece was formed, but recently, a probe card having 600 to 800 pins / piece and a pin pitch of 40 μm has become mainstream, and 2500 pins / piece. There are also cards.

  In addition, as the integration and speed of electronic components increase, the distance between the electrodes tends to become narrower. With conventional horizontal contact type probe cards, the contact probe slides from the side and overdrives when contacting. Troubles that damage adjacent electrodes are likely to occur. In order to solve such a drawback, a vertical contact type probe card in which a contact probe vertically contacts an electrode has been developed. This probe card has the advantage that the probe probe can be easily needled even if the probe card has a large number of pins and the contact area is widened.

  An example of a vertical contact type probe card is shown in FIG. The probe card shown in FIG. 3A has a contact probe 31 made of tungsten, and the contact probe 31 is soldered and fixed to a printed circuit board 32 on the inspection apparatus side with 31c. The contact probe 31 has a curved portion 31a between the two guide plates 33, passes through the guide plate 33, and protrudes toward the inspection object 34 side. When this probe card is pressed against an inspection target 34 such as a liquid crystal substrate perpendicularly in the direction of the arrow, the tip 31b of the contact probe 31 contacts the electrode 35 of the inspection target 34, and the curved portion 31a functions as a spring. Electrically conducting. The vertical contact type probe card shown in FIG. 3B includes a contact probe 31, and when the contact probe 31 is pressed vertically in the direction of the arrow, the tip 31 b of the contact probe 31 is connected to the electrode 35 of the inspection target 34. Can be contacted and inspected.

  Further, a silicon probe has been developed as a vertical probe card that can cope with miniaturization and high integration of electronic components. The silicon probe is a probe card using a silicon whisker formed by a VLS (Vapor Liquid Solid) growth technique as a contact probe. In VLS growth, a gold and silicon combined liquid is formed on a silicon single crystal, gas phase silicon tetrachloride and hydrogen are added, and silicon is introduced into the combined liquid by an air-flow interface reaction. Excess silicon is deposited at the interface to form a single crystal silicon whisker on the substrate. The silicon probe formed in this way is said to be capable of increasing the number of pins by narrowing the pin pitch to about 30 μm.

  In addition, although the prior art about this invention was demonstrated based on the general technical information which the applicant acquired, the information which should be disclosed as prior art document information before filing in the range which the applicant memorize | stores The applicant does not have

  In the vertical type probe card shown in FIG. 3A, since the contact probe is made by machining a tungsten wire, the variation in the overall length is large, and it is necessary to make a large stroke at the time of measurement. Therefore, there is a drawback that the variation in the needle pressure is large and the maximum needle pressure is increased. Further, operations such as contact probe bending, soldering, and wiring require accuracy in units of μm, resulting in poor workability and high work costs.

  In the vertical type probe card shown in FIG. 3B, the contact probe is not fixed in the stroke direction, and there is play in the probe card, so the preliminary stroke until obtaining electrical continuity is long. There is a drawback that stroke management during measurement is difficult. Further, as with the probe card shown in FIG. 3A, the assembly cost is high because precise assembly work is required. On the other hand, the silicon probe has a drawback that the contact probe cannot be replaced because the contact probe is manufactured on the silicon substrate at a time. Further, due to buckling deformation of the silicon contact probe, the contact load is extremely small, and the electrical contact property to materials other than gold is poor.

  An object of the present invention is to provide a contact probe that is fine and has high accuracy and good spring characteristics. Another object is to provide a contact probe that is easy to mount.

The contact probe of the present invention is a contact probe of a probe card for inspection,
It has a cantilever type spring part and a U-shaped spring part,
The end of the cantilever spring and the arm of the U-shaped spring are oriented in opposite directions.

  In such a contact probe, it is preferable that the arm portion of the U-shaped spring portion and the end portion of the cantilever spring portion are electrically connected to the wiring electrode in the probe card and the electrode of the inspection object.

  Moreover, the aspect fixed by one arm part of a U-shaped spring part is preferable, and the aspect which the arm part fixed among U-shaped spring parts orientates on the extension of a cantilever type | mold spring part is more preferable. The contact probe is preferably made of nickel or a nickel alloy, and has a coating layer made of noble metal, conductive diamond-like carbon, CrN or TiN.

The method of manufacturing the contact probe of the present invention is as follows:
Forming a resin mold with a mold;
And a step of forming a layer made of a metal material on a resin mold by electroforming.

Another aspect of the method for producing a contact probe of the present invention is as follows.
Forming a resin mold by X-ray lithography;
And a step of forming a layer made of a metal material on a resin mold by electroforming.

  The probe card of the present invention is a vertical probe card on which such a contact probe is mounted. Both arm portions of the U-shaped spring portion of the contact probe are inserted into holes in the substrate of the probe card, and one arm portion is inserted. A mode in which the contact probe is mounted by fixing is preferable. Further, it is preferable that the end portion of the cantilever spring portion of the contact probe is electrically connected to the wiring electrode in the probe card. The inspection apparatus of the present invention includes such a probe card, and is useful for inspection of semiconductors or liquid crystals.

  ADVANTAGE OF THE INVENTION According to this invention, it can respond to high integration and high-speed of an electronic component, and can provide a contact probe with easy mounting.

(Contact probe)
The contact probe of the present invention comprises a cantilever type spring part and a U-shaped spring part, and the end of the cantilever type spring part and the arm part of the U-shaped spring part are oriented in opposite directions to each other. To do. The contact probe of the present invention has both a spring electrode connected to the wiring electrode in the probe card and a spring electrode connected to the electrode of the object to be inspected. Since the number of parts is small, assembly and replacement are easy, and assembly is possible. Cost is low. In addition, since the end of the cantilever type spring part and the arm part of the U-shaped spring part are oriented in opposite directions and can be used in a structure that presses down the cantilever type spring part, the tip of the U-shaped spring part is Even when pressed in contact with the device, the entire contact probe is difficult to move and can function accurately as a spring. Therefore, it is preferable that one arm portion of the U-shaped spring portion and the end portion of the cantilever spring portion are electrically connected to the wiring electrode in the probe card and the electrode of the inspection object.

  A typical example of the contact probe of the present invention is shown in FIGS. 1 is a plan view, and FIG. 2 is a perspective view. As shown in FIG. 1, this contact probe includes a cantilever type spring portion 11 and a U-shaped spring portion 12, an end portion 11 a of the cantilever type spring portion 11, and arm portions 12 b and 12 c of the U-shaped spring portion 12. Are oriented in opposite directions. In the contact probe of the present invention, one arm portion of the U-shaped spring portion, for example, the arm portion 12c is fixed to the base substrate of the probe card, and the other arm portion of the U-shaped spring portion, for example, the arm portion 12b The cantilever spring 11 can be connected to the wiring electrode in the probe card and the electrode of the inspection object with an appropriate urging force. In the present invention, since the U-shaped spring is employed, the stroke and the contact load can be increased as compared with other springs. Specifically, the stroke of the U-shaped spring part can be 200 μm or more. The stroke of the cantilever type spring part is about 150 μm. Further, since one arm portion of the U-shaped spring portion is fixed and there is no play, no preliminary stroke is required until the U-shaped spring portion becomes conductive.

  The material of the contact probe is excellent in spring characteristics such as toughness and high hardness. Furthermore, it is suitable for manufacturing by the LIGA (Lithographie Galvanoformung Abformung) method described later. Nickel or nickel alloys such as nickel manganese Is preferred. Since the contact probe is also used for a wafer burn-in test and requires heat resistance, a nickel manganese alloy having excellent heat resistance is suitable as a material for the contact probe. Further, the nickel crystal grains are preferably 50 nm or less in order to increase the spring strength and elastic limit of the contact probe. A mode in which a coating layer of a noble metal such as gold, rhodium or palladium is preferably provided on the surface of the contact probe in terms of enhancing electrical contact and corrosion resistance. Further, if a coating layer made of conductive diamond-like carbon or CrN or TiN is formed on the surface of the contact probe, the wear resistance can be improved.

(Contact probe manufacturing method)
The contact probe manufacturing method of the present invention includes a step of forming a resin mold by X-ray lithography and a step of forming a layer made of a metal material on the resin mold by electroforming. In machining, only an accuracy of ± 10 μm can be obtained, but according to the method of the present invention, a highly accurate contact probe of ± 1 μm can be manufactured with good reproducibility. For this reason, since the spring characteristics can be kept uniform and the variation in the total length can be reduced, an unnecessary stroke for absorbing the variation in the tip position can be eliminated. Further, the fine structure can be integrally formed, the number of parts can be reduced, and the parts cost and assembly cost can be reduced. In the example shown in FIG. 1, the length (L) is 3 mm, the width (W) is 0.85 mm, and the thickness is 0.05 mm. However, the fine contact probe of 1/4 to 1/3 of the example shown in FIG. It can be produced with good reproducibility by the method of the present invention.

  In the production method of the present invention, X-rays (wavelength 0.4 nm) shorter than UV (wavelength 200 nm) are used in that a contact probe having a high aspect ratio is obtained. The X-ray (hereinafter referred to as “SR light”) having high synchrotron radiation is preferable. The LIGA method using SR light enables deep lithography, and a contact probe having a thickness of several hundreds of μm can be manufactured in large quantities with high accuracy on the order of μm. Further, since a high aspect ratio can be obtained, the contact strength is high and the contact reliability is large.

  In the manufacturing method of the present invention, a resin layer 42 is formed on a conductive substrate 41 as shown in FIG. As the conductive substrate, for example, a metal substrate made of copper, nickel, stainless steel, or the like can be used. Alternatively, a silicon substrate on which a metal material such as titanium or chromium is sputtered can be used. For the resin layer, a resin material mainly composed of polymethacrylate such as polymethyl methacrylate (PMMA) or a chemically amplified resin material sensitive to X-rays is used. The thickness of the resin layer can be arbitrarily set according to the thickness of the contact probe to be formed, and can be, for example, 40 μm to 500 mm.

  Next, a mask 43 is disposed on the resin material 42 and X-rays 44 are irradiated through the mask 43. As the X-ray, SR light is preferable. The mask 43 includes an X-ray absorption layer 43a formed according to a contact pattern and a translucent substrate 43b. Silicon nitride, silicon, diamond, titanium, or the like is used for the translucent substrate 43b. For the X-ray absorption layer 43a, a heavy metal such as gold, tungsten, or tantalum or a compound thereof is used. Of the resin layer 42, the resin layer 42a is exposed and deteriorated by the irradiation of the X-ray 44, but the resin layer 42b is not exposed by the X-ray absorption layer 43a. For this reason, only a portion that has been altered by the X-ray 44 is removed by development, and a resin mold 42b as shown in FIG. 4B is obtained.

  Next, electroforming is performed, and a metal material 45 is deposited on the resin mold 42b as shown in FIG. Electroforming refers to forming a layer made of a metal material on a conductive substrate using a metal ion solution. By performing electroforming using the conductive substrate 41 as a plating electrode, the metal material 45 can be deposited on the resin mold 42b. When the metal material 45 is deposited to such an extent that the holes of the resin mold 42b are filled, the contact probe of the present invention can be finally obtained from the deposited metal material layer. Further, when a metal material is deposited on the resin mold 42b exceeding the height of the resin mold 42b, the resin mold 42b and the substrate 41 are removed to obtain and obtain a metal microstructure having pores. Thus, the structure can be used effectively in the method for manufacturing a contact probe of the present invention using a mold described later.

  After electroforming, when a predetermined thickness is obtained by polishing or grinding, a structure as shown in FIG. 4D is obtained. Thereafter, as shown in FIG. 4E, the resin mold 42b is removed by wet etching or plasma etching. Subsequently, when the conductive substrate 41 is removed by wet etching with acid or alkali, or by machining, the contact probe of the present invention as shown in FIG. 4F can be obtained. The obtained contact probe can be coated with a coat layer made of gold having a thickness of 0.05 μm to 1 μm, if necessary.

  Another aspect of the method for manufacturing a contact probe of the present invention includes a step of forming a resin mold by a mold and a step of forming a layer made of a metal material on the resin mold by electroforming. Also with this method, a highly reliable contact probe having a uniform spring characteristic with high accuracy can be manufactured at low cost, as in the above-described manufacturing method of forming a resin mold by X-ray lithography. Also, mass production of contact probes is possible using the same mold.

  In this manufacturing method, as shown in FIG. 5A, a concave resin mold 53 as shown in FIG. 5B is formed by a mold such as press or injection molding using a mold 52 having convex portions. To do. As the resin, a thermoplastic resin such as an acrylic resin such as polymethyl methacrylate, a polyurethane resin, or a polyacetal resin such as polyoxymethylene is used. Since the mold 52 is a metal microstructure similar to the contact of the present invention, it is preferable to manufacture the mold 52 by the above-described method in which an X-ray lithography method and electroforming are combined.

  Next, after the resin mold 53 is turned upside down, it is attached to the conductive substrate 51 as shown in FIG. Subsequently, as shown in FIG. 5D, the resin mold 53 is polished to form the resin mold 53a. Thereafter, as described above, a metal material 55 is deposited on the resin mold 53a by electroforming (FIG. 5E), and after adjusting the thickness (FIG. 5F), the resin mold 53a is removed (FIG. 5). 5 (g)), when the conductive substrate 51 is removed, the contact probe of the present invention as shown in FIG. 5 (h) is obtained.

(Contact probe mounting)
The probe card of the present invention is a vertical contact type probe card on which such a contact probe is mounted. An example of mounting a contact probe is shown in FIG. 6A is a plan view showing a method of mounting the contact probe 62 on the base substrate 65 of the probe card, and FIG. 6B is a cross-sectional view of the probe card on which the contact probe 62 is mounted. First, as shown in FIG. 6A, the arms 62b and 62c of the U-shaped spring portion of the contact probe 62 are inserted into two holes formed in the base substrate 65 as indicated by arrows. Similarly, after inserting a plurality of contact probes into the holes of the base substrate, one arm portion of the U-shaped spring portion, for example, the arm portion 62c is fixed by a fixing plate 67 as shown in FIG. To do. Subsequently, when the base substrate 65 and the wiring substrate 63 are joined by, for example, screwing through the insert plate 66, the probe card of the present invention is obtained. By pressing this probe card against a substrate 64 such as an electronic device as an object to be inspected, as shown by an arrow in FIG. 6B, the electrode 64a on the substrate 64 and the contact probe 62 are connected, Electrical continuity between the probe card and the object to be inspected is obtained. Therefore, information on the object to be inspected is transmitted to the inspection apparatus via the electrode 64a, the contact probe 62, the electrode 63a, and the wiring 63b. By using an inspection apparatus provided with such a probe card, it is possible to inspect semiconductors and liquid crystals, which are increasingly integrated and increased in speed, at a low cost.

  The mounting method illustrated in FIG. 6 is a simple method in which two arms of the U-shaped spring part of the contact probe are inserted into two holes and one of the spring parts is fixed, and the assembly is easy. The method is preferable in that the assembly cost is low and mechanization is possible. Furthermore, the contact probe can be easily exchanged, the contact probe is properly fixed, and there is no play, so no preliminary stroke is required. It is preferable to join the base substrate 65 and the wiring substrate 63 via the insert plate 66 because the mechanical strength is increased. In addition, the aspect in which the fixed arm portion of the U-shaped spring portion is oriented on the extension of the cantilever spring portion can sufficiently utilize the spring characteristics of the cantilever spring portion and the U-shaped spring portion. it can. FIG. 6B shows an example in which the cantilever spring portion of the contact probe 62 protrudes from the wiring board 63 on the inspection apparatus side. On the other hand, the U-shaped spring portion of the contact probe 62 can be projected to the wiring board 63, but the U-shaped spring portion having a large stroke and contact load is directed to the inspection object side. The former mode shown in FIG. 6B is preferable.

  For the base substrate 65, polyimide resin, ceramics, silicon, or the like can be used. When a polyimide resin or ceramic is used, the base substrate can be drilled by laser processing or drilling. In the case of using silicon, the hole can be formed by wet etching or dry etching, but dry etching (ICP) in plasma gas is particularly preferable. In the base substrate 65, two holes are formed for one contact probe, and the positions of the holes correspond to the positions of the electrodes 64a of the inspection target 64.

  In the above example, the contact probe 62 is fixed to the base substrate 65 via the fixing plate 67 by screws or the like. As described above, in addition to the fixing plate, it can be fixed by an adhesive, but fixing by the fixing plate is preferable in terms of easy replacement of the contact probe. In the example shown in FIG. 6B, after the contact probe 62 is temporarily fixed by the fixing plate 67, the base substrate 65 and the wiring substrate 63 are joined, but without using the fixing plate 67, the base substrate 65 and The contact probe 62 may be fixed by being sandwiched between and pressed against the wiring board 63. In addition, a transformer may be provided between the contact probe 62 and the wiring board 63 to increase the pitch, and a multilayer ceramic substrate or a multilayer resin substrate with a built-in wiring can be used as the truss former. .

Example 1
First, as shown in FIG. 4A, the resin layer 42 was formed on the conductive substrate 41. As the conductive substrate, a silicon substrate obtained by sputtering titanium was used. As a material for forming the resin layer, a copolymer of methyl methacrylate and methacrylic acid was used, and the thickness of the resin layer was 70 μm.

  Next, a mask 43 was placed on the resin layer 42, and X-rays 44 were irradiated through the mask 43. X-rays were irradiated with SR light from an SR device (NIJI-III). As the mask 43, a mask having an X-ray absorption layer 43a made of a contact pattern is used. The translucent substrate 43b constituting the mask 43 is made of silicon nitride, and the X-ray absorption layer 43a is made of tungsten nitride. Using.

  After irradiation with X-rays 44, development with methyl isobutyl ketone was performed, and when a portion altered by X-rays 44 was removed, a resin mold 42b as shown in FIG. 4B was obtained. Next, electroforming was performed, and a metal material 45 was deposited in the holes of the resin mold 42b (FIG. 4C). Nickel was used as the metal material.

  After electroforming, polishing is performed to remove surface irregularities, and the contact probe thickness is adjusted to 50 μm (FIG. 4D), and the resin mold 42b is removed by oxygen plasma (FIG. 4E). When the conductive substrate 41 was removed by wet etching with an aqueous NaOH solution, a contact probe as shown in FIG. 4F was obtained. A plan view of the obtained contact probe is shown in FIG. A perspective view is shown in FIG. As shown in FIG. 1, the obtained contact probe includes a cantilever spring and a U-shaped spring, and the end of the cantilever spring and the arm of the U-shaped spring are oriented in opposite directions. It was.

  Subsequently, as shown in FIG. 6A, a contact probe 62 was mounted on a base substrate 65 in which a through hole was formed corresponding to the position of a semiconductor (LSI) electrode to be inspected. As shown in FIG. 6B, after mounting the arms 62c and 62b of the U-shaped spring portion of the contact probe 62 into the holes of the base board 65, the fixing plate 67 is screwed to fix the arms 62c. did. Subsequently, the wiring board 63 was attached to the base board 65 via the insert plate 66 and screwed. The base substrate 65 is made of polyimide resin and has a thickness of 1.2 mm. In the obtained probe card, the tip of the cantilever spring portion of the contact probe 62 is in contact with the electrode 63a on the wiring board 63, and the U-shaped spring of the contact probe from the surface of the base board 62 on the inspection object side. The part 62b protruded 0.5 mm.

  As shown by the arrow in FIG. 6B, the probe card is pressed against a substrate 64 such as an electronic device as an object to be inspected, whereby the arm portion of the U-shaped spring portion of the contact probe 62 and the cantilever spring. The end of each part electrically connected the wiring electrode 63a in the probe card and the electrode 64a of the object to be inspected. As a result, the information on the object to be inspected can be transmitted to the probe card via the electrode 64a, the contact probe 62, the electrode 63a, and the wiring 63b, and high integration and high speed can be achieved by the inspection apparatus including the probe card. Inspection of semiconductors and liquid crystals progressing at low cost was possible.

  The mounting method illustrated in FIG. 6 is a simple method in which the U-shaped spring part of the contact probe is inserted into the two holes and one of the spring parts is fixed, the assembly is easy, the assembly cost is low, and Mechanization was also possible. Further, the contact probe can be easily exchanged, the contact probe is properly fixed, and there is no play, so a preliminary stroke is not necessary.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  A contact probe that can cope with high integration and high speed of electronic components, a probe card including the contact probe, and an inspection apparatus including the probe card can be provided at low cost.

It is a top view of the contact probe of the present invention. It is a perspective view of the contact probe of the present invention. It is sectional drawing of the conventional perpendicular contact type probe card. It is process drawing which shows the manufacturing method of the contact probe of this invention. It is process drawing which shows the manufacturing method of the contact probe of this invention. It is a schematic diagram which shows the example of mounting of the contact probe of this invention.

Explanation of symbols

  11 Cantilever type spring part, 12 U-shaped spring part, 42b Resin mold, 44 X-ray, 45 Metal material, 52 Mold.

Claims (13)

A contact probe for an inspection probe card,
It has a cantilever type spring part and a U-shaped spring part,
A contact probe characterized in that the end of the cantilever spring and the arm of the U-shaped spring are oriented in opposite directions.   2. The contact probe according to claim 1, wherein the arm portion of the U-shaped spring portion and the end portion of the cantilever spring portion are electrically connected to the wiring electrode in the probe card and the electrode of the object to be inspected.   The contact probe according to claim 1, wherein the contact probe is fixed by one arm portion of the U-shaped spring portion.   The contact probe according to claim 3, wherein an arm portion to be fixed of the U-shaped spring portion is oriented on an extension of the cantilever spring portion.   The contact probe according to claim 1, wherein the contact probe is made of nickel or a nickel alloy.   The contact probe according to any one of claims 1 to 5, wherein the contact probe has a coat layer made of any of precious metal, conductive diamond-like carbon, CrN, or TiN. It is a manufacturing method of the contact probe in any one of Claims 1-6,
Forming a resin mold with a mold;
And a step of forming a layer made of a metal material on the resin mold by electroforming. It is a manufacturing method of the contact probe in any one of Claims 1-6,
Forming a resin mold by X-ray lithography;
And a step of forming a layer made of a metal material on the resin mold by electroforming.   A vertical probe card on which the contact probe according to claim 1 is mounted.   The probe card according to claim 9, wherein the contact probe is mounted by inserting both arm portions of the U-shaped spring portion of the contact probe into a hole of the substrate of the probe card and fixing one arm portion.   The probe card according to claim 9 or 10, wherein an end of the cantilever spring portion of the contact probe is electrically connected to a wiring electrode in the probe card.   A semiconductor or liquid crystal inspection method using the probe card according to claim 9.   An inspection apparatus comprising the probe card according to claim 9.

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