JP2006064511A - Metallic structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic structure having satisfactory springiness and low electric resistance, and having satisfactory shape accuracy. <P>SOLUTION: This metallic structure is equipped with a contact part making contact with an electric circuit, a spring part connected to the contact part, and a support part for supporting the spring part. This structure is characterized in that a front end part, positioned on a front end of the contact part and making direct contact with the electric circuit, has a multilayered structure of three or more layers comprising a spring metal layer, a high conductive layer, and/or an abrasion-resistant layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal structure such as a contact probe for measuring electrical characteristics of an electric circuit, a socket for inspection, or a connector terminal or a socket terminal connected to the electric circuit.

  A contact probe is used to inspect an electric circuit formed in a semiconductor chip, a liquid crystal display device, or the like. With the miniaturization of semiconductor chips and the like, the electrode pads are also miniaturized and the pitch is narrowed, so that contact probes are required to be miniaturized and miniaturized. In order to meet these requirements, contact probes manufactured by lithography and electroforming have been proposed.

  For example, as shown in FIG. 7, a contact probe manufactured by lithography and electroforming includes a contact part 71 that contacts a surface to be measured 70 such as an electric circuit, a spring part 72 connected to the contact part 71, and an inspection device. A contact probe is attached, and a support portion 73 that supports the spring portion 72 is provided. A contact probe having such a structure is pressed against a surface to be measured 70 such as an electric circuit in the direction of the arrow to inspect various electrical characteristics.

  On the other hand, in the field of semiconductor inspection, an increase in current value used for inspection is expected. For example, according to the ITRS roadmap, the electrode pitch is expected to be 175 μm in 2003 to 75 μm in 2007, and the current value is expected to be 150 mA in 2003 and 300 mA in 2007. . In addition, if there is an error, it is considered that several times the current flows. Thus, the contact probe is required to be small in size corresponding to a narrow pitch and to increase the allowable current value.

  Not only contact probes but also various connectors are highly demanded of narrow pitch. For example, in a board connector that connects a flexible printed circuit (FPC) and a printed board, the pitch is 300 μm or less, and there is a demand for narrowing the pitch to about 100 μm. For this reason, it has been proposed that terminals such as connectors and sockets are also manufactured by lithography and electroforming.

  As mentioned above, although the prior art about this invention was demonstrated based on the general technical information which the applicant acquired, the applicant does not have the information which should be disclosed as prior art document information before an application.

Conventionally, since contact probes manufactured by lithography and electroforming are made of the same material, first, the characteristics as a spring are emphasized, and materials such as Ni-Mn have been used. However, the Ni alloy has a large specific resistivity of 1.2 × 10 ⁷ Ωm and is not a good material from the viewpoint of the allowable current value.

  At present, connectors such as connectors and sockets with a wider pitch than contact probes are manufactured by stamping or etching a metal plate made of a single material. Good material is not used from the viewpoint of current value. In addition, in the case of manufacturing by lithography and electroforming, using Ni—Mn as described above is not a good material from the viewpoint of the allowable current value.

  As a method for solving such a problem, for example, a method of forming a spring with a single material and a material having good conductivity is conceivable, but in practice, such a material is formed by electroforming. difficult. This is because a material having good spring properties usually has a large number of crystal grain boundaries because the crystal grain size is small, but a crystal grain boundary is a place where electrical resistance is generated. This is because, when a material having many spring properties is used, the specific resistance value of the obtained structure must be increased.

  As another solution, there is a method in which a structure is manufactured from a material having a good spring property, and the whole or a part of the structure is coated with a material having a good conductivity by plating or the like. However, when the coating is made thick enough to obtain a sufficient conductive effect, a structure such as a contact probe formed with high accuracy is deformed, which adversely affects the electrical contact property or spring property at the tip.

  Further, since the tip of the contact probe is easily worn, it is desirable to manufacture the contact probe with a material having high wear resistance. On the other hand, the tip portion needs to have good conductivity. However, since the material having good electrical conductivity that has been used conventionally has a large crystal grain size, it has low hardness and low wear resistance, and is not suitable as a material for the tip portion. Therefore, when a material having good conductivity is coated, it is necessary to increase the wear resistance of the tip portion, and further, it has to be coated with a wear resistant material, which causes deformation of the structure.

  An object of the present invention is to provide a metal structure such as a contact probe or a connector having good spring properties and low electrical resistance and good shape accuracy.

  The metal structure of the present invention is a metal structure including a contact portion that contacts an electric circuit, a spring portion that is connected to the contact portion, and a support portion that supports the spring portion. The tip portion directly in contact with the circuit is characterized by having a multilayer structure of three or more layers including a spring metal layer, a highly conductive layer and / or a wear-resistant layer.

The multilayer structure at the tip is preferably a line-symmetric structure. The thickness T ₁ of the highly conductive layer at the tip is preferably 1/3 or less of the thickness T ₂ of the tip, and the thickness T ₄ of the wear-resistant layer at the tip is the thickness of the tip. 1/3 or less of the length T ₂ is preferable.

  The spring metal layer is made of nickel or a nickel alloy, the highly conductive layer is made of gold, silver, copper, ruthenium, rhodium, palladium-cobalt or an alloy based on these, and the wear-resistant layer is made of rhodium. Each aspect which consists of at least 1 sort (s) chosen from the group which consists of a rhodium alloy, a palladium-cobalt alloy, ruthenium, and chromium is preferable. Here, the main material means that the blending ratio in the total material is preferably 75% by mass or more, and more preferably 80% by mass or more.

  According to the present invention, it is possible to provide a metal structure having good spring properties, low electrical resistance, and good shape accuracy.

(Metal structure)
The metal structure of the present invention includes a contact portion that contacts an electric circuit, a spring portion that is connected to the contact portion, and a support portion that supports the spring portion. Such a metal structure includes a contact probe used for measuring electrical characteristics of an electric circuit, a test socket, a connector terminal or a socket terminal connected to the electric circuit, and the like.

  The metal structure of the present invention has a multi-layer structure of three or more layers, the tip of which is in contact with the electric circuit at the tip of the contact portion, and is composed of a spring metal layer, a highly conductive layer and / or a wear-resistant layer. It is characterized by having. With such a multilayer structure, the characteristics as a spring can be realized by the spring metal layer, and the allowable current value can be increased by the highly conductive layer. Further, in an electrical connection component that requires wear resistance such as a contact probe, the wear resistance can be increased by forming a wear-resistant layer. Furthermore, by using a multilayer structure of a spring metal layer, a highly conductive layer, and an abrasion resistant layer, a spring structure having a large allowable current value and high abrasion resistance can be obtained.

  In addition, by adopting a multi-layer structure, even if the thermal expansion coefficient or the internal stress of the material is different for each layer material, there is no change in the amount of warpage and warpage, and the shape balance is not lost. A structure can be provided. In terms of enhancing such an effect, it is preferable that the multi-layered structure at the distal end portion is axisymmetric including its material. Furthermore, among highly conductive materials, even if the internal stress at the time of plating is high and it is difficult to increase the thickness, it is possible to use the structure by sandwiching a large number of thin layers between spring metal layers. Further, even if the material is soft or brittle, the spring metal layer can be used because it maintains strength.

  FIG. 1C illustrates only the contact portion of the metal structure of the present invention. In the example shown in FIG. 1 (c), the tip portion 2 at the tip of the contact portion 1 and in direct contact with the electric circuit has a multilayer structure composed of the spring metal layer 4 (4a, 4b) and the highly conductive layer 3. Have. With such a multilayer structure, the characteristics as a spring can be realized by the spring metal layer, and the allowable current value can be increased by the highly conductive layer. In addition, by forming a highly conductive material layer with high conductivity and good wear resistance, it is possible to obtain both conductivity and wear resistance as a material for contact probes. Is preferred. FIG. 1C illustrates a case of three layers, but a multilayer structure composed of more constituent layers can be formed according to specifications required for the metal structure. By increasing the number of constituent layers, a large current can be passed while maintaining a stress balance.

  Another example of the metal structure of the present invention is shown in FIG. In the example shown in FIG. 6A, the tip 62 at the tip of the contact 61 directly contacts the electric circuit is formed by the spring metal layer 64 (64a, 64b, 64c), the highly conductive layer 63, and the resistance to resistance. It has a multilayer structure composed of a wear layer 65. By adopting such a multilayer structure, a high allowable current value and high wear resistance can be realized in a metal structure that also requires wear resistance, such as a contact probe. FIG. 6A shows an example of a five-layer structure, but the number of constituent layers can be further increased.

  By adopting such a multilayer structure, for example, even a highly conductive material that has a large internal stress during electroforming and is difficult to increase in thickness, a spring metal layer is formed as a large number of thin layers. It becomes possible to use it by making it the structure inserted | pinched between. Moreover, even if it is a soft material or a brittle material, a spring metal layer can be utilized in order to maintain strength. Furthermore, even if the thermal expansion coefficient or internal stress differs for each layer material, such a multi-layer structure does not cause warpage, the amount of warpage does not change, and the balance of the shape is lost. A highly accurate metal structure can be obtained.

  When used as a contact probe, the tip of the contact portion contacts the electric circuit. Therefore, as shown in FIG. 2D and FIG. 3D, it is preferable to increase the contact pressure with the electric circuit to be inspected by processing the tip portions 22 and 32 to be thin. In the contact portion shown in FIG. 2D, the tip portion 22 has a three-layer structure including a spring metal layer 24 (24 a, 24 b) and a highly conductive layer 23. The same applies to the contact portion shown in FIG. 3D, and the tip portion 32 has a three-layer structure including the spring metal layer 34 (34 a, 34 b) and the highly conductive layer 33.

  The spring metal layer is preferably made of nickel or a nickel alloy because it has excellent spring characteristics such as toughness, high hardness, and is suitable for production by electroforming described later. When the metal structure of the present invention is used as a contact probe, a nickel-manganese alloy is suitable because it is also used for a wafer burn-in test and requires heat resistance. The composition ratio of the alloy varies depending on the use, but from the viewpoint of electrodeposition efficiency during electroforming, 0.01 mass% to 0.3 mass% of nickel is preferable, and 0.01 mass% to 0.15 of manganese. The mass% is more preferable.

The highly conductive layer is preferably made of gold, silver or copper, or a gold alloy, silver alloy or copper alloy. Since these metals are soft, they could not be used as springs in the past. However, in the present invention, a high-conductivity of these metals can be used by forming a multilayer structure sandwiched between the spring metal layers and retaining the spring property by the spring metal layers. For example, the specific resistivity of silver is 1.6 × 10 ⁻⁸ Ωm, which is 1/7 of the specific resistivity of Ni—Mn, so that 1/7 of the total thickness at the tip is the silver layer. As a result, the conductivity of the tip can be doubled.

Similarly, the specific resistivity of gold is 2.4 × 10 ⁻⁸ Ωm, the specific resistivity of copper is 1.7 × 10 ⁻⁸ Ωm, and since the specific resistivity is small, it is between the spring metal layers. By sandwiching, the conductivity can be improved while maintaining the spring characteristics. In addition, since these highly conductive materials have high thermal conductivity, resistance heating can be suppressed by increasing the conductivity, and the generated heat can be easily released, thereby contributing to an improvement in the allowable current value. From such a viewpoint, as shown in FIGS. 2D and 3D, the thickness T ₁ of the highly conductive layer at the tip is preferably 1/3 or less of the thickness T ₂ of the tip.

The wear-resistant layer is preferably made of chromium. Chromium has a hardness of about 1000 Hv and good wear resistance. Therefore, the wear resistance of the entire tip can be improved by sandwiching the layer made of chromium between the spring metal layers. Although it is difficult to form a thick film with a single material, chromium can be used by forming a multilayer structure like the above-described highly conductive layer. From such a viewpoint, as shown in FIG. 6A, the thickness T ₄ of the wear-resistant layer at the tip is preferably 1/3 or less of the thickness T ₂ of the tip.

  Moreover, the aspect which consists of at least 1 sort (s) chosen from the group which a wear-resistant layer becomes from rhodium, a rhodium alloy, a palladium-cobalt alloy, and ruthenium is preferable. Rhodium, a rhodium alloy, a palladium-cobalt alloy, and ruthenium are useful as materials for the metal structure of the present invention because they are wear-resistant and have high conductivity.

  Rhodium is more preferable in that it has the lowest specific resistivity among the platinum group, high hardness, and good wear resistance. Rhodium has a large internal stress, is difficult to form a thick film, and is a relatively brittle material. In the present invention, it can be effectively used by forming a spring metal layer and a multilayer structure. Ruthenium is useful in that it has the same properties as rhodium in terms of conductivity and hardness, and is low in cost. Since it is difficult to form a thick film of ruthenium, it cannot be used alone as a material for a contact probe or the like, but effectiveness can be obtained by using a multilayer structure.

  Rhodium alloys and palladium-cobalt alloys likewise have both high electrical conductivity and wear resistance. As the rhodium alloy, an alloy with platinum, iridium, iron, manganese, or the like is preferable from the viewpoint of improving hardness and heat resistance. The composition ratio of the alloy varies depending on the type of metal to be blended, but from the viewpoint of maintaining the conductivity and the limit of electroforming, an aspect of blending at a ratio of 10% by mass or less of rhodium is preferable. On the other hand, the composition ratio of the palladium-cobalt alloy is preferably an aspect in which cobalt is blended at a ratio of 5% by mass to 25% by mass with respect to palladium from the viewpoint of maintaining electrical conductivity, and the blending ratio of cobalt is 10% by mass. -20 mass% is more preferable.

(Metal structure manufacturing method)
The method for producing a metal structure of the present invention includes a step of forming a resin mold by lithography, a resin mold on a conductive substrate, a three-layer structure comprising a spring metal layer, a highly conductive layer and / or an abrasion-resistant layer. It includes a step of forming the above layers by electroforming, a step of polishing or grinding, a step of removing the resin mold, and a step of removing the conductive substrate. Since three or more layers of spring metal layers and the like are formed on one resin mold, it is not necessary to perform lithography and electroforming a plurality of times, the process is simple, and the manufacturing cost can be reduced. Further, in machining, only accuracy of about ± 10 μm can be obtained, but according to the method of the present invention, a highly accurate metal structure of ± 1 μm can be easily manufactured with good reproducibility and the material composition is uniform. . Therefore, the spring characteristics can be kept uniform. Furthermore, variations in the overall length can be reduced, and the occurrence of excessive stress can be suppressed even for brittle electrodes. Further, since the fine structure can be integrally formed, the number of parts can be reduced, and the part cost and the assembly cost can be reduced.

  Specifically, as shown in FIG. 4A, first, a resin layer 42 is formed on a conductive substrate 41. As the conductive substrate, for example, a metal substrate made of copper, nickel, stainless steel, aluminum, or the like can be used. Alternatively, a silicon substrate or a glass substrate on which a metal material such as titanium, aluminum, copper, 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 ultraviolet rays (UV) or X-rays is used. The thickness of the resin layer can be arbitrarily set according to the thickness of the metal structure to be formed, and can be, for example, 40 μm to 500 μm.

  Next, a mask 43 is disposed on the resin material 42, and UV or X-ray 44 is irradiated through the mask 43. In the production method of the present invention, it is preferable to use X-rays (wavelength 0.4 nm) having a shorter wavelength than UV (wavelength 200 nm) in that a metal structure having a high aspect ratio is obtained. Further, it is more preferable to use synchrotron radiation X-ray (hereinafter referred to as “SR”) having high directivity among X-rays. The LIGA method using SR is capable of deep lithography, and can manufacture a metal structure having a thickness of several hundreds of micrometers with a high accuracy on the order of microns.

  The mask 43 includes an absorbing layer 43a such as UV or X-ray 44 formed according to the pattern of the metal structure, and a translucent substrate 43b. In the case of an X-ray mask, silicon nitride, silicon, diamond, titanium, or the like is used for the translucent substrate 43b. The absorption layer 43a is made of heavy metal such as gold, tungsten, or tantalum or a compound thereof. Of the resin layer 42, the resin layer 42a of the resin layer 42 is exposed and deteriorated by the irradiation of the X-ray 44, but the resin layer 42b is not exposed by the absorption layer 43a. For this reason, in the case of a positive type resin, only the part that has been altered (molecular chain is cut) is removed by development, and a resin type comprising a resin layer 42b as shown in FIG. 4B is obtained.

  Next, electroforming is performed, and as shown in FIG. 4C, three or more metal material layers 45 including a spring metal layer and a highly conductive layer are deposited on the resin mold. 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 layer 45 can be deposited on the resin mold. When the metal material layer 45 is deposited to such an extent that the resin-type holes are filled, the metal structure of the present invention can be finally obtained from the deposited metal material layer.

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

  Other aspects of the method for producing a metal structure of the present invention include a step of forming a resin mold with a mold, a step of forming a layer made of a metal material on the resin mold on an electroconductive substrate by electroforming, polishing or It includes a step of grinding, a step of removing the resin mold, and a step of removing the conductive substrate. Also by such a method, a metal structure having a good stress balance and little warpage can be manufactured, as in the above-described manufacturing method of forming a resin mold by lithography. Further, since the fine structure can be integrally formed, the number of parts can be reduced, and the part cost and the assembly cost can be reduced. Furthermore, mass production is possible using the same mold.

  As shown in FIG. 5 (a), this manufacturing method uses a mold 52 having a convex portion and molds such as emboss molding, reactive molding or injection molding to form a concave shape as shown in FIG. 5 (b). A resin mold 53 is formed. 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 metal structure of the present invention, it is preferable to manufacture the mold 52 by the above-described method in which a lithography method and electroforming are combined. However, in this case, it is not necessary to have a multilayer structure.

  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, in the same manner as described above, three or more metal material layers 55 composed of a spring metal layer and a highly conductive layer are deposited on the resin mold 53a by electroforming (FIG. 5E), and the thickness is obtained by polishing or grinding. (FIG. 5F), the resin mold 53a is removed (FIG. 5G), and the conductive substrate 51 is removed. As a result, the metal structure of the present invention as shown in FIG. can get.

  About the manufacturing method of the metal structure of this invention, only a contact part is taken up and it shows in FIGS. 1-3. The method shown in FIG. 1 is an embodiment in which tip processing is not performed. First, in the electroforming process described above, a spring metal layer 4b is formed in a resin-shaped hole (not shown) (FIG. 1A), and then the highly conductive layer 3 is formed on the spring metal layer 4b. Finally, the spring metal layer 4a is formed on the highly conductive layer 3 to complete the electroforming. By setting the two spring metal layers 4 to the same thickness, the multilayer structure at the tip portion is line-symmetric including the material composition, and a metal structure with a good stress balance can be obtained.

  The method shown in FIG. 2 is a mode in which a part of the tip of the contact portion is removed. First, a spring metal layer 24b is formed in a resin-type hole (not shown) (FIG. 2A), and then a highly conductive layer 23 is formed on the spring metal layer 24b (FIG. b)) Subsequently, the spring metal layer 24c is formed on the highly conductive layer 23 (FIG. 2C), and finally the spring metal layer 24c is partially removed (FIG. 2D). Since the tip processing can be performed collectively after forming each layer, it is not necessary to form each layer by lithography and electroforming, and the manufacturing cost can be reduced. By removing a part of the tip and aligning the thickness of the spring metal layer 24a at the tip 22 of the contact portion 21 with the thickness of the spring metal layer 24b, the multilayer structure at the tip 22 is axisymmetric.

  The method shown in FIG. 3 is an embodiment in which the tip of the contact portion is electropolished. First, a spring metal layer 34c is formed in a resin-type hole (not shown) (FIG. 3A), and then a highly conductive layer 33 is formed on the spring metal layer 34c (FIG. 3 ( b)) Subsequently, a spring metal layer 34d is formed on the highly conductive layer 33 (FIG. 3C), and finally, the spring metal layers 34c and 34d are electropolished (FIG. 3D). By aligning the thicknesses of the spring metal layers 34a and 34b at the distal end portion 32 of the contact portion 31, the multilayer structure at the distal end portion 32 is axisymmetric. In addition, the tip processing of the contact portion can be performed by mechanical polishing or chemical etching.

Example 1
First, as shown in FIG. 4A, the resin layer 42 was formed on the conductive substrate 41. A substrate made of stainless steel was used as the conductive substrate. The material for forming the resin layer was acrylic resin, and the thickness of the resin layer was 60 μm.

  Next, a mask 43 was placed on the resin layer 42, and X-rays 44 were irradiated through the mask 43. SR was irradiated as X-rays. As the mask 43, a mask having an absorption layer 43a composed of a plurality of contact probe patterns was used. The translucent substrate 43b was made of silicon nitride, and the absorbing layer 43a was made of tungsten nitride.

  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 composed of a resin layer 42b as shown in FIG. 4B was obtained. Next, electroforming was performed, and a metal material layer 45 was deposited in the resin mold holes (FIG. 4C).

  In the electroforming process, first, a nickel-manganese layer having a thickness of 20 μm was formed as a first spring metal layer using a nickel sulfamate-manganese bath. Next, after washing and surface activation treatment, a rhodium layer having a thickness of 10 μm was formed as a second wear-resistant layer and highly conductive layer by a rhodium sulfate bath. Subsequently, after washing and surface activation treatment, a nickel-manganese layer is formed as a third spring metal layer by the same plating bath as the first layer until it overflows from a resin mold having a depth of 60 μm. did.

  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 is removed by plasma ashing (FIG. 4E). The conductive substrate 41 was removed to obtain a contact probe as shown in FIG.

  The obtained contact probe has a three-layer structure in which a rhodium wear-resistant and highly conductive layer having a thickness of 10 μm is sandwiched between two nickel-manganese spring metal layers having a thickness of 20 μm. It was 4 mm. Further, the warpage at the total length of 4 mm was 2 μm or less, which was the same as that of a conventional contact probe having a single layer structure made of nickel-manganese. Subsequently, when the state of warping was observed while heating from room temperature (25 ° C.) to 200 ° C., the warp was 3 μm at maximum, but it was the same warp as a conventional nickel-manganese single-layer contact probe. It was.

  Simulating an electrode pad of an IC, an Al film having a thickness of 0.7 μm was formed on a Si substrate by sputtering to prepare a specimen. The electrical resistance of the object measured using the contact probe manufactured in this example is 0.18Ω, which is compared with 0.23Ω which is a measurement value of a conventional nickel-manganese single layer contact probe. The resistance value was as low as 20% or more. In addition, a load of 5 g was applied to the contact probe manufactured in this example, and the contact test was performed 100,000 times with a stroke of 100 μm on the subject, but no probe breakage and delamination were observed.

Example 2
A nickel-manganese layer having a thickness of 5 μm is formed as a first spring metal layer, a rhodium layer having a thickness of 5 μm is formed as a second wear-resistant and highly conductive layer, and a third layer is formed. A contact probe was manufactured in the same manner as in Example 1 except that a nickel-manganese layer having a thickness of 40 μm was formed as a spring metal layer, and after removing the resin mold, a part of the tip was removed on the conductive substrate. A sectional view of the contact portion of this contact probe is shown in FIG. As shown in FIG. 2 (d), the _second thickness T ₂ of the range of 20μm from the tip 22 is machined such that 15 [mu] m. As a result, the tip 22 has a three-layer structure including a spring metal layer 24a having a thickness of 5 μm, a wear-resistant and highly conductive layer 23 having a thickness of 5 μm, and a spring metal layer 24b having a thickness of 5 μm. .

  This contact probe had a warp of 2 μm or less at a total length of 4 mm, and this warp was not increased even by heat treatment up to 200 ° C. Moreover, the electrical resistance with respect to the specimen was 0.18Ω, and no damage or delamination was observed in the 100,000 contact test. Furthermore, the change in electrical resistance due to the 10,000 contact tests is 0.18Ω → 0.4Ω in this example, and 0.23Ω → 2.0Ω with a conventional nickel-manganese single layer contact probe. Compared with the results, it was found that the product of this example was very stable.

  Next, the tip of a conventional nickel-manganese single-layer contact probe was processed in the same manner as in this example. This conventional contact probe was subjected to the above contact test 100,000 times, and as a result, the tip was worn by 4 μm to 5 μm. On the other hand, the wear in this example product was 2 μm to 3 μm, indicating that the hardness was high. Further, a short experiment was performed by energizing the subject used in the above contact test with a contact load of 5 g and a current of 1 A for 1 second. As a result, the tip portion melted in the conventional product and the contact probe function such as springiness was lost, whereas the contact probe function was maintained in the present embodiment product.

Example 3
A contact probe was produced in the same manner as in Example 1 except that the contact portion of the contact probe was electropolished. The electrolytic polishing was performed by immersing a range of 50 μm from the tip of the contact portion in hydrochloric acid (pH 1.0). The obtained contact probe is shown in FIG. The contact probe was subjected to 10,000 contact tests in the same manner as in Example 2. As a result, the electrical resistance value changed from 0.18Ω to 0.4Ω as in Example 2.

Example 4
A contact probe was produced in the same manner as in Example 2 except that the second wear-resistant and highly conductive layer was formed using a palladium sulfamate-cobalt bath to form a 5 μm-thick palladium-cobalt layer. did. The warpage at the full length of 4 mm was further as small as 1 μm, and the warp was not increased even by heat treatment up to 200 ° C. Moreover, the electrical resistance performed similarly was 0.19 (ohm), and neither damage nor delamination was observed in the contact test of 100,000 times. Furthermore, the change in electric resistance after 10,000 contact tests was 0.19Ω → 0.41Ω, which was found to be very stable.

  Further, the wear of the product of this example by 100,000 contact tests was 1 μm to 2 μm, and it was found that the product of this example had higher durability than the conventional product. Furthermore, as a result of performing a short experiment, the tip portion melted in the conventional product and the contact probe function such as the spring property was lost, whereas the contact probe function was maintained in the product of this example.

Example 5
At the tip, the first spring metal layer is a nickel-manganese layer with a thickness of 3 μm, the second wear-resistant and highly conductive layer is a ruthenium layer with a thickness of 2 μm, and the third layer The spring metal layer is a 3 μm thick nickel-manganese layer, the fourth wear-resistant and highly conductive layer is a 2 μm thick ruthenium layer, and the fifth spring metal layer is a 3 μm thick nickel layer. A contact probe was produced in the same manner as in Example 2 except that the manganese layer was used.

  A short experiment was conducted on the contact probes of this example and Example 2. As a result, the tip of the contact probe of Example 2 melted due to a current of 1.5A and lost its function, while the product of this example maintained its function even when the current was increased to 2.1A. Was.

Example 6
The first spring metal layer is a nickel-manganese layer having a thickness of 10 μm, the second highly conductive layer is a silver layer having a thickness of 5 μm, and the third spring metal layer is a nickel-manganese layer having a thickness of 10 μm. The fourth highly conductive layer is a 5 μm thick silver layer, the fifth spring metal layer is a 10 μm thick nickel-manganese layer, and a connector terminal is manufactured in the same manner as in Example 1. did. When the resistance value was measured for this example, the resistance value was reduced to about 1 / 2.5 compared to the connector terminal made of only nickel-manganese.

Example 7
As shown in FIG. 6A, the first spring metal layer 64c is a nickel-manganese layer having a thickness of 5 μm, and the second wear-resistant and highly conductive layer 65 is rhodium having a thickness of 5 μm. A third spring metal layer 64b is a nickel-manganese layer having a thickness of 10 μm, a fourth highly conductive layer 63 is a silver layer having a thickness of 5 μm, and a fifth spring metal layer 64a is formed. Was made into a nickel-manganese layer having a thickness of 20 μm, and a connector terminal was produced in the same manner as in Example 1.

  Subsequently, in the same manner as in Example 2, the portion from the tip 62 to 20 μm was removed so that the thickness became 15 μm, and a connector terminal as shown in FIG. 6B was obtained. The obtained connector terminal had a contact resistance of 0.14Ω to aluminum having a thickness of 0.7 μm, which was 40% lower than the conventional one. Further, the wear by the contact test of 100,000 times was about 2 μm, and this point was also improved from the conventional product.

  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, an inspection socket, a connector terminal, a socket terminal, or the like having good spring properties, low electrical resistance, and good shape accuracy can be provided.

It is process drawing which shows the manufacturing method of the contact part in the metal structure of this invention. It is process drawing which shows the manufacturing method of the contact part in the metal structure of this invention. It is process drawing which shows the manufacturing method of the contact part in the metal structure of this invention. It is process drawing which shows the manufacturing method of the metal structure of this invention. It is process drawing which shows the manufacturing method of the metal structure of this invention. It is a schematic diagram which shows the structure of the contact part in the contact probe of this invention. It is a schematic diagram which shows the structure of the conventional contact probe.

Explanation of symbols

  1, 21, 31 Contact portion, 2, 22, 32 Tip portion, 3, 23, 33 Highly conductive layer, 4, 24, 34 Spring metal layer.

Claims (7)

  In a metal structure including a contact portion that contacts an electrical circuit, a spring portion connected to the contact portion, and a support portion that supports the spring portion, the metal structure is in direct contact with the electrical circuit at the tip of the contact portion. A metal structure characterized in that the tip portion has a multilayer structure of three or more layers comprising a spring metal layer and a highly conductive layer and / or an abrasion-resistant layer.   The metal structure according to claim 1, wherein the multilayer structure at the tip is a line-symmetric structure. 3. The metal structure according to claim 1, wherein a thickness T ₁ of the highly conductive layer at the tip portion is 1/3 or less of a thickness T ₂ of the tip portion. Wherein the distal end portion, the thickness T ₄ of the abrasion-resistant layer is a metal structure according to any one of claims 1 to 3 or less 1/3 of the thickness T ₂ of the tip.   The metal structure according to claim 1, wherein the spring metal layer is made of nickel or a nickel alloy.   The metal structure according to claim 1, wherein the highly conductive layer is made of gold, silver, copper, ruthenium, rhodium, palladium-cobalt, or an alloy mainly composed of these.   The metal structure according to claim 1, wherein the wear-resistant layer is made of at least one selected from the group consisting of rhodium, rhodium alloy, palladium-cobalt alloy, ruthenium, and chromium.

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