WO2021131693A1 - Wiring board - Google Patents

Wiring board Download PDF

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Publication number
WO2021131693A1
WO2021131693A1 PCT/JP2020/045787 JP2020045787W WO2021131693A1 WO 2021131693 A1 WO2021131693 A1 WO 2021131693A1 JP 2020045787 W JP2020045787 W JP 2020045787W WO 2021131693 A1 WO2021131693 A1 WO 2021131693A1
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WO
WIPO (PCT)
Prior art keywords
layer
conductive layer
molybdenum
tungsten
wiring board
Prior art date
Application number
PCT/JP2020/045787
Other languages
French (fr)
Japanese (ja)
Inventor
山本　哲也
孝友 緒方
陽彦 伊藤
Original Assignee
Ｎｇｋエレクトロデバイス株式会社
日本碍子株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Ｎｇｋエレクトロデバイス株式会社, 日本碍子株式会社 filed Critical Ｎｇｋエレクトロデバイス株式会社
Priority to CN202080047926.XA priority Critical patent/CN114026968B/en
Priority to JP2021567191A priority patent/JP7001876B2/en
Publication of WO2021131693A1 publication Critical patent/WO2021131693A1/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/10—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminium oxide
    • C04B35/111—Fine ceramics
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
    • H05K3/12—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using thick film techniques, e.g. printing techniques to apply the conductive material or similar techniques for applying conductive paste or ink patterns

Definitions

  • the present invention relates to a wiring board, and more particularly to a wiring board having an insulator layer made of ceramic and a conductive layer provided on the insulator layer.
  • Patent Document 1 electroless gold is applied to a wiring pattern (metallized surface) formed on a ceramic surface containing alumina of an integrated circuit package or an electronic circuit substrate.
  • the technique of plating is being studied. Specifically, a metallized paste containing W and Mo is applied to the ceramic surface, and this is fired at, for example, 1500 ° C. It is claimed that a thick electroless gold plating layer can be formed on the metallized surface formed by this in a short time.
  • Patent Document 2 an electroplating method or an electroless plating method is applied to the surfaces of the external electrode and the wiring conductor of the wiring board. For example, a nickel plating layer and a gold plating layer are sequentially formed.
  • Patent Document 3 a configuration in which a seal ring is bonded on a multilayer ceramic structure is disclosed.
  • the multilayer ceramic structure has a ceramic insulating layer and wiring.
  • the ceramic insulating layer is made of alumina and the wiring is made of tungsten.
  • the seal ring consists of, for example, an alloy containing iron, nickel and cobalt.
  • JP-A-51-107306 it is disclosed that a metallized paste containing W and Mo is fired at a high temperature of 1500 ° C.
  • the firing temperature is high as described above, according to the study of the present inventor, even if the metal component of the metallized paste is only tungsten, the sintering can easily proceed sufficiently, so that the mechanical strength can be easily secured. it can.
  • the metal component is only tungsten, high water resistance (corrosion resistance to humidity and moisture) can be obtained as compared with the case where molybdenum is contained. Therefore, unless the purpose is to directly form a thick electroless gold-plated layer on the metallized surface in a short time, the usefulness of JP-A-51-107306 seems to be low.
  • the technique of JP-A-51-107306 does not seem to have any meaning. ..
  • the size of alumina crystal grains constituting the ceramic insulator layer may be reduced in order to increase the mechanical strength of the ceramic insulator layer constituting the wiring board.
  • the particle size of the alumina powder which is the material of the ceramic insulator layer, is also reduced, and thus the suitable firing temperature is lowered. Therefore, the material of the conductive layer that constitutes the wiring board by being laminated with the insulator layer also needs to be suitable for low-temperature sintering.
  • the metal component of the conductive layer is preferably molybdenum (rather than tungsten) as described in JP-A-2015 / 88642.
  • the metal component of the metallized paste as the material of the conductive layer is simply tungsten, it is difficult for sintering to proceed sufficiently at a low firing temperature. As a result, the mechanical strength of the conductive layer is lowered. On the other hand, according to the study of the present inventor, when the metal component is simply molybdenum, the water resistance (corrosion resistance to humidity and moisture) of the conductive layer may be insufficient.
  • the present invention has been made to solve the above problems, and an object of the present invention is to provide a wiring board including a conductive layer having high mechanical strength and high water resistance (corrosion resistance to humidity and moisture). To provide.
  • the wiring board of the present invention includes an insulator layer made of ceramic containing alumina and a conductive layer provided on the insulator layer.
  • the conductive layer includes a plurality of core portions dispersed in the conductive layer and containing molybdenum, and a coating portion that covers the surface of each of the plurality of core portions and contains tungsten.
  • the coating has a lower molybdenum concentration and a higher tungsten concentration than the core.
  • the core portion preferably has a molybdenum concentration of 80 wt% (weight percent) or more and 95 wt% or less.
  • V W Molybdenum volume when the conductive layer is regarded as molybdenum atoms and metallic molybdenum containing defined as V M
  • tungsten volume of when the conductive layer is regarded as a tungsten atoms containing a metal tungsten is defined as V W, V M
  • V W is preferably 20% or more and 50% or less.
  • the wiring board may include a base layer provided directly on the conductive layer and made of a conductor different from gold, and a gold layer provided on the conductive layer at least via the base layer.
  • the base layer preferably contains nickel.
  • the wiring board may include a metal frame bonded to the base layer and covered with a gold layer.
  • the conductive layer since the conductive layer has a core portion containing molybdenum at a relatively high concentration, the conductive layer can be sufficiently sintered even when the firing temperature in the production of the wiring board is low. Become. As a result, it is easy to secure sufficient mechanical strength of the conductive layer. Further, corrosion of the core portion is suppressed by covering each surface of the core portion with a coating portion containing tungsten at a relatively high concentration. From the above, it is possible to obtain a conductive layer having high mechanical strength and high corrosion resistance against humidity and moisture even when the firing temperature is low.
  • FIG. 1 It is a top view which shows schematic structure of the wiring board in embodiment of this invention. It is a schematic partial cross-sectional view along the line II-II of FIG. It is sectional drawing which shows typically the fine structure of the conductive layer in FIG. Shown shows a reflected electron image of a cross section of a laminate composed of an insulator layer, a conductive layer having a metal component having a converted volume of tungsten of 0 vol% and a converted volume of molybdenum of 100 vol%, and a nickel-plated layer in an initial state. It is an electron micrograph.
  • FIG. 6 is a surface photograph of a laminate composed of an insulator layer and a conductive layer having a metal component having a converted volume of tungsten of 0 vol% and a converted volume of molybdenum of 100 vol% in an initial state by a 20-magnification optical microscope.
  • the conductive layer having a metal component having a converted volume of tungsten of 0 vol% and the converted volume of molybdenum of 100 vol% After the pressure cooker test, on the insulator layer, the conductive layer having a metal component having a converted volume of tungsten of 0 vol% and the converted volume of molybdenum of 100 vol%, the nickel plating layer formed on the conductive layer, and the nickel plating layer.
  • Shown shows a reflected electron image of a cross section of a laminate composed of an insulator layer, a conductive layer having a metal component having a converted volume of tungsten of 50 vol% and a converted volume of molybdenum of 50 vol%, and a nickel plating layer in an initial state. It is an electron micrograph. A surface photograph of a laminate composed of an insulator layer and a conductive layer having a metal component having a converted volume of tungsten of 50 vol% and a converted volume of molybdenum of 50 vol% after a high temperature and high humidity test by a 20-magnification optical microscope. Is.
  • Shown shows a reflected electron image of a cross section of a laminate composed of an insulator layer, a conductive layer having a metal component having a converted volume of tungsten of 20 vol% and a converted volume of molybdenum of 80 vol%, and a nickel plating layer in an initial state. It is an electron micrograph. A surface photograph of a laminate composed of an insulator layer and a conductive layer having a metal component having a converted volume of tungsten of 20 vol% and a converted volume of molybdenum of 80 vol% after a high-temperature and high-humidity test by a 20-magnification optical microscope. Is.
  • a laminate composed of an insulator layer in an initial state and a conductive layer having a metal component having a converted volume of tungsten of 35 vol% and a converted volume of molybdenum of 65 vol%, which is the laminate shown in FIG. Is an electron micrograph showing a reflected electron image of a cross section of what was prepared separately. It is a distribution map which shows the concentration distribution of molybdenum measured by EDX of the cross section shown in FIG. 15 in the same field of view as FIG. It is a distribution map which shows the concentration distribution of tungsten measured by EDX of the cross section shown in FIG. 15 in the same field of view as FIG.
  • FIG. 1 is a plan view schematically showing the configuration of the wiring board 90 according to the present embodiment.
  • FIG. 2 is a schematic partial cross-sectional view taken along line II-II of FIG.
  • the wiring board 90 is a package used for manufacturing a module. As shown in FIG. 2, the electronic component 81 is mounted on the package, and then the lid 82 is attached to the package to obtain a module having the electronic component 81 in the sealed space.
  • the wiring board 90 has insulator layers 11 and 12 made of ceramic containing alumina as a main component, and conductive layers 21 to 23 provided on the insulator layers 11 and 12.
  • the alumina content of the ceramic may be 70 wt% or more. Further, the ceramic may contain 10 to 30 wt% of zirconia for the purpose of increasing its strength. Further, the ceramic may contain several% of a glass component for the purpose of increasing the adhesion strength between the insulator layers 11 and 12 and the conductive layers 21 to 23. Further, the wiring board 90 may have a via electrode 26. In the configuration shown in FIG.
  • the conductive layer 21 is laminated on the lower surface of the insulator layer 11, and the conductive layer 22 and the insulator layer 12 are laminated on the upper surface of the insulator layer 11 to insulate.
  • the conductive layer 23 is laminated on the upper surface of the body layer 12.
  • the insulator layer 12 has a frame shape, and a region surrounded by the frame shape on the insulator layer 11 constitutes a cavity for accommodating the electronic component 81.
  • the via electrode 26 connects the conductive layer 21 and the conductive layer 22 to each other by penetrating the insulator layer 11.
  • the laminate can be formed by forming a plurality of green sheets, printing a metallized paste on each green sheet, laminating these green sheets, and firing.
  • Insulator layers 11 and 12 are formed by sintering the green sheet, and conductive layers 21 to 23 and via electrodes 26 are formed by sintering the metallized paste.
  • the metallized paste has a solvent and a powder dispersed therein. This powder contains a powder of metallic molybdenum and a powder of metallic tungsten.
  • the metallized paste may further contain a powder of the additive, preferably having a composition similar to that of the insulator layers 11 and 12.
  • the wiring board 90 further has a base plating layer 31 to 33 (base layer), an intermediate plating layer 41 to 43, and an Au plating layer 51 to 53 (gold layer).
  • the intermediate plating layers 41 to 43 may be omitted.
  • the wiring board 90 further has a metal frame body 62 welded by the brazing material portion 61.
  • Each of the base plating layers 31 to 33 is provided directly on the conductive layers 21 to 23.
  • the base plating layers 31 to 33 are made of a conductor different from gold, preferably containing nickel, and are made of, for example, nickel or a nickel-cobalt alloy.
  • the intermediate plating layers 41 to 43 are made of a conductor different from gold, preferably nickel-containing, and are made of, for example, nickel or a nickel-cobalt alloy.
  • the Au plating layer 51 is provided on the conductive layer 21 at least via the base plating layer 31, and the Au plating layer 52 is provided on the conductive layer 22 via at least the base plating layer 32. 53 is provided on the conductive layer 23 via at least the base plating layer 33.
  • the Au plating layer 51 is provided on the base plating layer 31 via the intermediate plating layer 41.
  • the Au plating layer 52 is provided on the base plating layer 32 via the intermediate plating layer 42.
  • the Au plating layer 53 is provided on the base plating layer 33 via an intermediate plating layer 43. More specifically, the Au plating layer 53 is placed on the base plating layer 33 with a brazing material portion 61 and a metal frame 62. And is provided via an intermediate plating layer 43.
  • the metal frame body 62 is joined to the base plating layer 33 by the brazing material portion 61.
  • the metal frame 62 is covered with the Au plating layer 53 via the intermediate plating layer 43.
  • the lid 82 will be welded onto the plated metal frame 62.
  • the metal frame 62 is made of a metal, and this metal may be an alloy.
  • FIG. 3 is a cross-sectional view schematically showing the fine structure of the conductive layers 21 to 23 (FIG. 2).
  • the covering portion 72 is shown in white without hatching in order to make the figure easier to see.
  • the conductive layers 21 to 23 have a plurality of core portions 71 dispersed in the conductive layers 21 to 23 and a coating portion 72 that covers the surface of each of the plurality of core portions 71 as a microstructure that can be observed with a microscope. including.
  • Each of the conductive layers 21 to 23 preferably further includes an alumina-containing additive portion 73 as a microstructure that can be observed with a microscope. In that case, both the conductive layers 21 to 23 and the insulator layer containing alumina are included. The joint strength between 11 and 12 is increased.
  • the additive portion 73 may contain a glass component, which promotes sintering of the conductive layers 21 to 23.
  • the covering portion 72 completely covers the surface of each of the plurality of core portions 71, but the present invention is not limited to this, and a part of the plurality of core portions 71 is exposed without being covered by the covering portion 72. You may. That is, it is sufficient that the surface of most of the core portions 71 among the plurality of core portions 71 is covered with the covering portion 72.
  • the outline of each core portion 71 is relative to the total value of the outline lengths of each core portion 71.
  • the total length of the portions forming the boundary line with the covering portion 72 was 80% or more.
  • the core portion 71 contains a molybdenum atom, preferably has a molybdenum concentration of 80 wt% or more and 95 wt% or less, and may be substantially composed of molybdenum.
  • the covering portion 72 contains a tungsten atom and has a lower molybdenum concentration and a higher tungsten concentration than the core portion 71.
  • Molybdenum atoms conductive layers 21 to 23 contain the converted volume of molybdenum when regarded as metallic molybdenum is defined as V M, in terms of tungsten in the case where the conductive layers 21 to 23 is regarded as a tungsten atom and a metal tungsten containing the volume is defined as V W, defining the sum of these terms the volume V M and V W to 100%. Under these definitions, the converted volume V W is preferably in the range of 20% or more and 50% or less.
  • the metallized paste which is a material of the conductive layers 21 to 23, and the powder of the powder and metallic tungsten metal molybdenum, volume ratio satisfies the above range V M: at V W It suffices if it is mixed.
  • the alloying between the molybdenum and tungsten is preferably not very advanced, ignoring the effect of alloying, the conductive layers 21 to 23, in terms of volume V M Corresponds to the volume of the core portion 71, and the converted volume V W corresponds to the volume of the covering portion 72.
  • the metal components in the conductive layers 21 to 23 may be substantially only molybdenum and tungsten.
  • the conductive layers 21 to 23 have the core portion 71 containing molybdenum at a relatively high concentration, the conductive layer is formed even when the firing temperature in the production of the wiring board 90 is low. 21 to 23 are sufficiently easy to sinter. As a result, it is easy to secure sufficient mechanical strength of the conductive layers 21 to 23. Further, the coating portion 72 containing tungsten in a relatively high concentration covers each surface of the core portion 71, so that the corrosion of the core portion 71 is suppressed. From the above, it is possible to obtain conductive layers 21 to 23 having high mechanical strength and high corrosion resistance against humidity and moisture even when the firing temperature is low.
  • the core portion 71 preferably has a molybdenum concentration of 80 wt% or more and 95 wt% or less. This makes it easier for the conductive layers 21 to 23 to sinter.
  • concentration is less than 80 wt%, the molybdenum concentration of the covering portion 72 is relatively increased. In this case, the moisture resistance of the covering portion 72 itself is lowered.
  • concentration exceeds 95 wt%, the moisture resistance of the core portion 71 decreases. In this case, the portion of the surface of the core portion 71 that is not covered with the covering portion 72 is particularly susceptible to corrosion.
  • the covering portion 72 containing tungsten can more sufficiently cover each surface of the core portion 71. If converted volume V W is less than 50%, can be more ensured converted volume V M of molybdenum, sintering of the conductive layers 21 to 23, it is possible to proceed more thoroughly.
  • the Au plating layers 51 to 53 are directly bonded to the conductive layers 21 to 23, the Au plating layers 51 to 53 are easily peeled off. Therefore, it is preferable that the Au plating layers 51 to 53 are provided via the base plating layers 31 to 33 directly provided on the conductive layers 21 to 23.
  • the base plating layers 31 to 33 contain nickel.
  • the nickel in the base plating layers 31 to 33 is alloyed with the tungsten or molybdenum in the conductive layers 21 to 23, so that the base plating layers 31 to 33 are firmly bonded to the conductive layers 21 to 23.
  • the wiring board 90 may include a metal frame 62 (FIG. 2) bonded to the base plating layers 31 to 33 and covered with Au plating layers 51 to 53. Since the metal frame 62 is a relatively thick member, there is a relatively high possibility that a large external force will be received from the lateral direction in FIG. 2 for some reason. Further, the metal frame body 62 is likely to receive a force applied to the lid 82, which is a large member, due to some factor, almost as it is. Therefore, a large force may be applied to the conductive layer 23 that supports the metal frame body 62. Even in such a case, since the base plating layer 33 is firmly bonded to the conductive layer 23, the occurrence of peeling on the conductive layer 23 is prevented.
  • a metal frame 62 (FIG. 2) bonded to the base plating layers 31 to 33 and covered with Au plating layers 51 to 53. Since the metal frame 62 is a relatively thick member, there is a relatively high possibility that a large external force will be received from the lateral direction in
  • FIG. 4 shows a cross section of a sample to which the Ni plating layer 40 is attached for convenience of observation in the initial state (in other words, the state before being exposed to an environment that easily promotes oxidation).
  • the initial state in other words, the state before being exposed to an environment that easily promotes oxidation.
  • tungsten was not added, so that the core portion 71 and the additive portion 73 were distributed without the coating portion 72 (FIG. 3).
  • FIG. 5 shows the surface of the sample without the plating layer in the initial state.
  • the surface image of the conductive layer 20 by a 20-magnification optical microscope is almost white, indicating that the conductive layer 20 has not yet been oxidized.
  • FIG. 6 shows the surface of the sample after the high temperature and high humidity test.
  • the high temperature and high humidity test described in the present specification was performed under the conditions of a temperature of 85 ° C., a relative humidity of 85%, and a period of 96 hours.
  • the surface image of the conductive layer 20 by a 20-magnification optical microscope was substantially black, indicating that the conductive layer 20 was considerably oxidized.
  • FIG. 7 shows a cross section of the sample with the Ni plating layer 40 and the Au plating layer 50 after the pressure cooker test (PCT) near the end of the conductive layer 20 (the position indicated by the broken line ED).
  • the PCT was performed under the conditions of a temperature of 121 ° C., a relative humidity of 100%, a pressure of 2 atm, and a period of 1000 hours.
  • ED pressure cooker test
  • FIG. 8 shows the surface of a sample without a plating layer after a high temperature and high humidity test.
  • the conductive layer 20 of this sample does not contain molybdenum, it has only low mechanical strength.
  • FIG. 9 shows a cross section of a sample to which the Ni plating layer 40 is attached for convenience of observation in the initial state.
  • the core portion 71 gray portion of the conductive layer 20 in FIG. 9
  • the covering portion 72 white portion of the conductive layer 20 in FIG. 9
  • the portion) and the additive portion 73 were distributed, and the coating portion 72 almost completely covered the surface of each of the core portions 71.
  • FIG. 9 shows a cross section of a sample to which the Ni plating layer 40 is attached for convenience of observation in the initial state.
  • FIG. 11 shows a cross section of a sample to which the Ni plating layer 40 is attached for convenience of observation in the initial state. Also in this sample, the coating portion 72 almost completely covered each surface of the core portion 71.
  • FIG. 13 shows a cross section of a sample to which the Ni plating layer 40 is attached for convenience of observation in the initial state.
  • the coating portion 72 roughly covered each surface of the core portion 71.
  • the boundary line between the outer line of each core portion 71 and the covering portion 72 is relative to the total value of the lengths of the outer lines of each core portion 71.
  • the total length of the portions forming the sword was 80% or more.
  • EDX Error-Dispersive X-Ray Spectrometry
  • the cross section of the observation sample was made by ion milling, and carbon vapor deposition was performed on it.
  • Hitachi High-Technologies S-3400N was used for observing the backscattered electron image.
  • Genesis MX4 manufactured by EDAX was used for EDX.
  • the acceleration voltage in EDX was 10 kV, and the signal strength was measured by scanning for 150 seconds in the measurement field of view.
  • FIG. 15 shows a reflected electron image of a cross section of the sample without the Ni plating layer 40 (see FIG. 9) in the initial state.
  • FIG. 16 shows the results of measuring the distribution of molybdenum concentration in the same field of view as in FIG. 15 with EDX.
  • FIG. 17 shows the result of measuring the distribution of the tungsten concentration in the same field of view as in FIG. 15 with EDX.
  • the visual field range of the conductive layer was about 24 ⁇ m ⁇ about 12 ⁇ m.
  • Arrow 1 in FIGS. 15 to 17 indicates the position of the core portion 71.
  • the arrow 2 indicates the position of the covering portion 72.
  • the coating portion 72 indicated by the arrow 2 has a lower whiteness than the core portion 71 indicated by the arrow 1, it can be said that the coating portion 72 has a lower molybdenum concentration than the core portion 71.
  • the element concentration of the core portion 71 was measured by EDX by irradiating the vicinity of the central portion of the core portion 71 with an electron beam. Specifically, three core portions having different positions were arbitrarily selected, and measurements were taken at positions A to C near the center of each. The results are shown in Table 1 below.
  • the molybdenum concentration of the core portion 71 is less than 80 wt%, the molybdenum concentration of the coating portion 72 is relatively high. In this case, the moisture resistance of the covering portion 72 itself is lowered, and as shown in FIG. 6, oxidative corrosion may proceed after the high temperature and high humidity test. On the other hand, when the molybdenum concentration of the core portion 71 exceeds 95 wt%, the moisture resistance of the core portion 71 is lowered. In this case, as shown in FIG. 6, oxidative corrosion may particularly progress after the high temperature and high humidity test on the portion of the surface of the core portion 71 that is not covered by the coating portion 72.
  • the element concentration was measured by EDX while irradiating the entire surface of the conductor layer 20 of FIG. 15 with an electron beam.
  • the weight percent ratio of tungsten to molybdenum was substantially the same as the weight percent ratio of metal molybdenum to metal tungsten in the metallized paste which is the material of the conductor layer 20.

Abstract

A wiring board (90) according to the present invention comprises: insulator layers (11, 12) which are formed of a ceramic that contains alumina; and conductive layers (21-23) which are provided on the insulator layers (11, 12). Each one of the conductive layers (21-23) comprises: a plurality of core parts (71) which are dispersed in the conductive layer, while containing molybdenum; and a cover part (72) which covers the surfaces of the plurality of core parts (71), while containing tungsten. The cover part (72) has a lower molybdenum concentration and a higher tungsten concentration in comparison to the core parts (71).

Description

配線基板Wiring board
　本発明は、配線基板に関し、特に、セラミックからなる絶縁体層と、絶縁体層上に設けられた導電層とを有する配線基板に関する。 The present invention relates to a wiring board, and more particularly to a wiring board having an insulator layer made of ceramic and a conductive layer provided on the insulator layer.
　特開昭５１－１０７３０６号公報（特許文献１）によれば、集積回路用パッケージまたは電子回路基板の、アルミナを含有するセラミック表面に形成された配線パターン（金属化面）に対して無電解金めっきを施す技術について検討がなされている。具体的には、セラミック表面に、ＷおよびＭｏを含有するメタライズペーストが塗布され、これが、例えば１５００℃で焼成される。これにより形成された金属化面には、短時間に厚い無電解金めっき層を形成することができる旨が主張されている。 According to Japanese Patent Application Laid-Open No. 51-107306 (Patent Document 1), electroless gold is applied to a wiring pattern (metallized surface) formed on a ceramic surface containing alumina of an integrated circuit package or an electronic circuit substrate. The technique of plating is being studied. Specifically, a metallized paste containing W and Mo is applied to the ceramic surface, and this is fired at, for example, 1500 ° C. It is claimed that a thick electroless gold plating layer can be formed on the metallized surface formed by this in a short time.
　国際公開第２０１８／１５５４３４号（特許文献２）によれば、配線基板が有する外部電極および配線導体の表面に、電気めっき法または無電解めっき法が施される。例えば、ニッケルめっき層と、金めっき層とが、順次形成される。 According to International Publication No. 2018/155434 (Patent Document 2), an electroplating method or an electroless plating method is applied to the surfaces of the external electrode and the wiring conductor of the wiring board. For example, a nickel plating layer and a gold plating layer are sequentially formed.
　特開２０１５－８８６４２号公報（特許文献３）によれば、多層セラミック構造体上にシールリングが接合された構成が開示されている。多層セラミック構造体はセラミック絶縁層および配線を有している。例えば、セラミック絶縁層はアルミナからなり、配線はタングステンからなる。シールリングに蓋が溶接されることによって、気密封止されたキャビティが得られる。シールリングは、例えば、鉄、ニッケルおよびコバルトを含有する合金からなる。 According to Japanese Patent Application Laid-Open No. 2015-88642 (Patent Document 3), a configuration in which a seal ring is bonded on a multilayer ceramic structure is disclosed. The multilayer ceramic structure has a ceramic insulating layer and wiring. For example, the ceramic insulating layer is made of alumina and the wiring is made of tungsten. By welding the lid to the seal ring, an airtightly sealed cavity is obtained. The seal ring consists of, for example, an alloy containing iron, nickel and cobalt.
特開昭５１－１０７３０６号公報Japanese Unexamined Patent Publication No. 51-107306 国際公開第２０１８／１５５４３４号International Publication No. 2018/155434 特開２０１５－８８６４２号公報Japanese Unexamined Patent Publication No. 2015-88642
　上記特開昭５１－１０７３０６号公報の技術によれば、ＷおよびＭｏを含有するメタライズペーストが、１５００℃の高温で焼成されることが開示されている。このように焼成温度が高い場合、本発明者の検討によれば、メタライズペーストの金属成分がタングステンのみであっても焼結を十分に進行させやすいので、機械的強度を容易に確保することができる。そして、金属成分がタングステンのみであれば、モリブデンが含有される場合に比して、高い耐水性（湿度および水分に対する耐腐食性）が得られる。よって、金属化面上に短時間に厚い無電解金めっき層を直接的に形成することが目的とされていない限り、上記特開昭５１－１０７３０６号公報の有用性は低いようにみえる。特に、上記国際公開第２０１８／１５５４３４号に記載のように、金めっき層がニッケルめっき層を介して形成される場合、上記特開昭５１－１０７３０６号公報の技術は意味を有しないようにみえる。 According to the technique of JP-A-51-107306, it is disclosed that a metallized paste containing W and Mo is fired at a high temperature of 1500 ° C. When the firing temperature is high as described above, according to the study of the present inventor, even if the metal component of the metallized paste is only tungsten, the sintering can easily proceed sufficiently, so that the mechanical strength can be easily secured. it can. When the metal component is only tungsten, high water resistance (corrosion resistance to humidity and moisture) can be obtained as compared with the case where molybdenum is contained. Therefore, unless the purpose is to directly form a thick electroless gold-plated layer on the metallized surface in a short time, the usefulness of JP-A-51-107306 seems to be low. In particular, when the gold-plated layer is formed via the nickel-plated layer as described in International Publication No. 2018/155434, the technique of JP-A-51-107306 does not seem to have any meaning. ..
　近年、配線基板を構成するセラミック絶縁体層の機械的強度を高める目的で、セラミック絶縁体層を構成するアルミナ結晶粒の大きさが小さくされる場合がある。この場合、セラミック絶縁体層の材料であるアルミナ粉体の粒径も小さくされ、よってそれに適した焼成温度は低くなる。したがって、絶縁体層と積層されることによって配線基板を構成する導電層の材料も、低温焼結に適したものである必要がある。低温焼結の観点では、導電層の金属成分は、上記特開２０１５／８８６４２号公報に記載されているように、（タングステンよりは）モリブデンであることが好ましい。もしも導電層の材料としてのメタライズペーストの金属成分が単純にタングステンであるとすると、低い焼成温度では焼結が十分には進行しにくい。その結果、導電層の機械的強度が低くなる。一方で、本発明者の検討によれば、金属成分が単純にモリブデンである場合は、導電層の耐水性（湿度および水分に対する耐腐食性）が不十分となることがある。 In recent years, the size of alumina crystal grains constituting the ceramic insulator layer may be reduced in order to increase the mechanical strength of the ceramic insulator layer constituting the wiring board. In this case, the particle size of the alumina powder, which is the material of the ceramic insulator layer, is also reduced, and thus the suitable firing temperature is lowered. Therefore, the material of the conductive layer that constitutes the wiring board by being laminated with the insulator layer also needs to be suitable for low-temperature sintering. From the viewpoint of low-temperature sintering, the metal component of the conductive layer is preferably molybdenum (rather than tungsten) as described in JP-A-2015 / 88642. If the metal component of the metallized paste as the material of the conductive layer is simply tungsten, it is difficult for sintering to proceed sufficiently at a low firing temperature. As a result, the mechanical strength of the conductive layer is lowered. On the other hand, according to the study of the present inventor, when the metal component is simply molybdenum, the water resistance (corrosion resistance to humidity and moisture) of the conductive layer may be insufficient.
　本発明は以上のような課題を解決するためになされたものであり、その目的は、高い機械的強度と高い耐水性（湿度および水分に対する耐腐食性）とを有する導電層を含む配線基板を提供することである。 The present invention has been made to solve the above problems, and an object of the present invention is to provide a wiring board including a conductive layer having high mechanical strength and high water resistance (corrosion resistance to humidity and moisture). To provide.
　本発明の配線基板は、アルミナを含有するセラミックからなる絶縁体層と、絶縁体層上に設けられた導電層と、を含む。導電層は、導電層中に分散されモリブデンを含有する複数のコア部と、複数のコア部の各々の表面を被覆しタングステンを含有する被覆部と、を含む。被覆部はコア部に比して、より低いモリブデン濃度と、より高いタングステン濃度とを有している。 The wiring board of the present invention includes an insulator layer made of ceramic containing alumina and a conductive layer provided on the insulator layer. The conductive layer includes a plurality of core portions dispersed in the conductive layer and containing molybdenum, and a coating portion that covers the surface of each of the plurality of core portions and contains tungsten. The coating has a lower molybdenum concentration and a higher tungsten concentration than the core.
　コア部は、８０ｗｔ％（重量パーセント）以上９５ｗｔ％以下のモリブデン濃度を有していることが好ましい。 The core portion preferably has a molybdenum concentration of 80 wt% (weight percent) or more and 95 wt% or less.
　導電層が含有するモリブデン原子を金属モリブデンとみなした場合のモリブデン体積をＶＭと定義し、導電層が含有するタングステン原子を金属タングステンとみなした場合のタングステン体積をＶＷと定義し、ＶＭおよびＶＷの和を１００％（パーセント）と定義すると、ＶＷは２０％以上５０％以下であることが好ましい。 Molybdenum volume when the conductive layer is regarded as molybdenum atoms and metallic molybdenum containing defined as V M, tungsten volume of when the conductive layer is regarded as a tungsten atoms containing a metal tungsten is defined as V W, V M When the sum of V W and V W is defined as 100% (percentage), V W is preferably 20% or more and 50% or less.
　配線基板は、導電層上に直接的に設けられ金とは異なる導体からなる下地層と、導電層上に少なくとも下地層を介して設けられた金層と、を含んでよい。 The wiring board may include a base layer provided directly on the conductive layer and made of a conductor different from gold, and a gold layer provided on the conductive layer at least via the base layer.
　下地層はニッケルを含有していることが好ましい。 The base layer preferably contains nickel.
　配線基板は、下地層に接合され金層によって覆われた金属枠体を含んでよい。 The wiring board may include a metal frame bonded to the base layer and covered with a gold layer.
　本発明によれば、相対的に高濃度にモリブデンを含有するコア部を導電層が有することによって、配線基板の製造における焼成温度が低い場合であっても、導電層が十分に焼結しやすくなる。これにより導電層の十分な機械的強度が確保しやすい。また、相対的に高濃度にタングステンを含有する被覆部がコア部の各々の表面を覆うことによって、コア部の腐食が抑制される。以上から、焼成温度が低い場合であっても、高い機械的強度と、湿度および水分に対する高い耐腐食性とを有する導電層を得ることができる。 According to the present invention, since the conductive layer has a core portion containing molybdenum at a relatively high concentration, the conductive layer can be sufficiently sintered even when the firing temperature in the production of the wiring board is low. Become. As a result, it is easy to secure sufficient mechanical strength of the conductive layer. Further, corrosion of the core portion is suppressed by covering each surface of the core portion with a coating portion containing tungsten at a relatively high concentration. From the above, it is possible to obtain a conductive layer having high mechanical strength and high corrosion resistance against humidity and moisture even when the firing temperature is low.
　この発明の目的、特徴、局面、および利点は、以下の詳細な説明と添付図面とによって、より明白となる。 The objectives, features, aspects, and advantages of the present invention will be made clearer by the following detailed description and accompanying drawings.
本発明の実施の形態における配線基板の構成を概略的に示す平面図である。It is a top view which shows schematic structure of the wiring board in embodiment of this invention. 図１の線ＩＩ－ＩＩに沿う概略的な部分断面図である。It is a schematic partial cross-sectional view along the line II-II of FIG. 図２における導電層の微細構造を模式的に示す断面図である。It is sectional drawing which shows typically the fine structure of the conductive layer in FIG. 初期状態における、絶縁体層と、タングステンの換算体積０ｖｏｌ％かつモリブデンの換算体積１００ｖｏｌ％の金属成分を有する導電層と、ニッケルめっき層と、によって構成された積層体の断面の反射電子像を示す電子顕微鏡写真である。Shown shows a reflected electron image of a cross section of a laminate composed of an insulator layer, a conductive layer having a metal component having a converted volume of tungsten of 0 vol% and a converted volume of molybdenum of 100 vol%, and a nickel-plated layer in an initial state. It is an electron micrograph. 初期状態における、絶縁体層と、タングステンの換算体積０ｖｏｌ％かつモリブデンの換算体積１００ｖｏｌ％の金属成分を有する導電層と、によって構成された積層体の、２０倍率の光学顕微鏡による表面写真である。6 is a surface photograph of a laminate composed of an insulator layer and a conductive layer having a metal component having a converted volume of tungsten of 0 vol% and a converted volume of molybdenum of 100 vol% in an initial state by a 20-magnification optical microscope. 高温高湿試験後における、絶縁体層と、タングステンの換算体積０ｖｏｌ％かつモリブデンの換算体積１００ｖｏｌ％の金属成分を有する導電層と、によって構成された積層体の、２０倍率の光学顕微鏡による表面写真である。A surface photograph of a laminate composed of an insulator layer and a conductive layer having a metal component having a converted volume of tungsten of 0 vol% and a converted volume of molybdenum of 100 vol% after a high-temperature and high-humidity test by a 20-magnification optical microscope. Is. プレッシャークッカー試験後における、絶縁体層と、タングステンの換算体積０ｖｏｌ％かつモリブデンの換算体積１００ｖｏｌ％の金属成分を有する導電層と、導電層上に形成されたニッケルめっき層と、ニッケルめっき層上に形成された金めっき層と、によって構成された積層体の、導電層の端近傍での断面の反射電子像を示す電子顕微鏡写真である。After the pressure cooker test, on the insulator layer, the conductive layer having a metal component having a converted volume of tungsten of 0 vol% and the converted volume of molybdenum of 100 vol%, the nickel plating layer formed on the conductive layer, and the nickel plating layer. It is an electron micrograph which shows the reflected electron image of the cross section in the vicinity of the edge of the conductive layer of the laminated body composed of the formed gold plating layer. 高温高湿試験後における、絶縁体層と、タングステンの換算体積１００ｖｏｌ％かつモリブデンの換算体積０ｖｏｌ％の金属成分を有する導電層と、によって構成された積層体の、２０倍率の光学顕微鏡による表面写真である。A surface photograph of a laminate composed of an insulator layer and a conductive layer having a metal component having a converted volume of tungsten of 100 vol% and a converted volume of molybdenum of 0 vol% after a high-temperature and high-humidity test by a 20-magnification optical microscope. Is. 初期状態における、絶縁体層と、タングステンの換算体積３５ｖｏｌ％かつモリブデンの換算体積６５ｖｏｌ％の金属成分を有する導電層と、ニッケルめっき層と、によって構成された積層体の断面の反射電子像を示す電子顕微鏡写真である。Shown shows a reflected electron image of a cross section of a laminate composed of an insulator layer, a conductive layer having a metal component having a converted volume of tungsten of 35 vol% and a converted volume of molybdenum of 65 vol%, and a nickel plating layer in an initial state. It is an electron micrograph. 高温高湿試験後における、絶縁体層と、タングステンの換算体積３５ｖｏｌ％かつモリブデンの換算体積６５ｖｏｌ％の金属成分を有する導電層と、によって構成された積層体の、２０倍率の光学顕微鏡による表面写真である。A surface photograph of a laminate composed of an insulator layer and a conductive layer having a metal component having a converted volume of tungsten of 35 vol% and a converted volume of molybdenum of 65 vol% after a high temperature and high humidity test by a 20-magnification optical microscope. Is. 初期状態における、絶縁体層と、タングステンの換算体積５０ｖｏｌ％かつモリブデンの換算体積５０ｖｏｌ％の金属成分を有する導電層と、ニッケルめっき層と、によって構成された積層体の断面の反射電子像を示す電子顕微鏡写真である。Shown shows a reflected electron image of a cross section of a laminate composed of an insulator layer, a conductive layer having a metal component having a converted volume of tungsten of 50 vol% and a converted volume of molybdenum of 50 vol%, and a nickel plating layer in an initial state. It is an electron micrograph. 高温高湿試験後における、絶縁体層と、タングステンの換算体積５０ｖｏｌ％かつモリブデンの換算体積５０ｖｏｌ％の金属成分を有する導電層と、によって構成された積層体の、２０倍率の光学顕微鏡による表面写真である。A surface photograph of a laminate composed of an insulator layer and a conductive layer having a metal component having a converted volume of tungsten of 50 vol% and a converted volume of molybdenum of 50 vol% after a high temperature and high humidity test by a 20-magnification optical microscope. Is. 初期状態における、絶縁体層と、タングステンの換算体積２０ｖｏｌ％かつモリブデンの換算体積８０ｖｏｌ％の金属成分を有する導電層と、ニッケルめっき層と、によって構成された積層体の断面の反射電子像を示す電子顕微鏡写真である。Shown shows a reflected electron image of a cross section of a laminate composed of an insulator layer, a conductive layer having a metal component having a converted volume of tungsten of 20 vol% and a converted volume of molybdenum of 80 vol%, and a nickel plating layer in an initial state. It is an electron micrograph. 高温高湿試験後における、絶縁体層と、タングステンの換算体積２０ｖｏｌ％かつモリブデンの換算体積８０ｖｏｌ％の金属成分を有する導電層と、によって構成された積層体の、２０倍率の光学顕微鏡による表面写真である。A surface photograph of a laminate composed of an insulator layer and a conductive layer having a metal component having a converted volume of tungsten of 20 vol% and a converted volume of molybdenum of 80 vol% after a high-temperature and high-humidity test by a 20-magnification optical microscope. Is. 初期状態における、絶縁体層と、タングステンの換算体積３５ｖｏｌ％かつモリブデンの換算体積６５ｖｏｌ％の金属成分を有する導電層と、によって構成された積層体であって、図９に示された積層体とは別個に準備されたものの断面の反射電子像を示す電子顕微鏡写真である。A laminate composed of an insulator layer in an initial state and a conductive layer having a metal component having a converted volume of tungsten of 35 vol% and a converted volume of molybdenum of 65 vol%, which is the laminate shown in FIG. Is an electron micrograph showing a reflected electron image of a cross section of what was prepared separately. 図１５に示された断面の、ＥＤＸで測定された、モリブデンの濃度分布を、図１５と同じ視野で示す分布図である。It is a distribution map which shows the concentration distribution of molybdenum measured by EDX of the cross section shown in FIG. 15 in the same field of view as FIG. 図１５に示された断面の、ＥＤＸで測定された、タングステンの濃度分布を、図１５と同じ視野で示す分布図である。It is a distribution map which shows the concentration distribution of tungsten measured by EDX of the cross section shown in FIG. 15 in the same field of view as FIG.
　以下、図面に基づいて本発明の実施の形態について説明する。なお、以下の図面において同一または相当する部分には同一の参照番号を付しその説明は繰返さない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings below, the same or corresponding parts are given the same reference numbers, and the explanations are not repeated.
　＜構成＞
　図１は、本実施の形態における配線基板９０の構成を概略的に示す平面図である。図２は、図１の線ＩＩ－ＩＩに沿う概略的な部分断面図である。 <Structure>
FIG. 1 is a plan view schematically showing the configuration of the wiring board 90 according to the present embodiment. FIG. 2 is a schematic partial cross-sectional view taken along line II-II of FIG.
　配線基板９０は、モジュールを製造するために用いられるパッケージである。図２に示されているように、パッケージに電子部品８１が搭載され、その後にパッケージに蓋８２が取り付けられることによって、密封された空間中に電子部品８１を有するモジュールが得られる。 The wiring board 90 is a package used for manufacturing a module. As shown in FIG. 2, the electronic component 81 is mounted on the package, and then the lid 82 is attached to the package to obtain a module having the electronic component 81 in the sealed space.
　配線基板９０は、主成分としてアルミナを含有するセラミックからなる絶縁体層１１，１２と、絶縁体層１１，１２上に設けられた導電層２１～２３とを有している。当該セラミックのアルミナ含有量は７０ｗｔ％以上であってよい。また当該セラミックは、その強度を高める目的で、ジルコニアを１０～３０ｗｔ％含んでいてもよい。また当該セラミックは、絶縁体層１１，１２と導電層２１～２３との密着強度を高める目的で、ガラス成分を数％含有していてもよい。さらに、配線基板９０はビア電極２６を有していてよい。図２に示された構成においては、絶縁体層１１の下面上に導電層２１が積層されており、絶縁体層１１の上面上に導電層２２および絶縁体層１２が積層されており、絶縁体層１２の上面上に導電層２３が積層されている。絶縁体層１２は枠形状を有しており、絶縁体層１１上においてこの枠形状に囲まれた領域が、電子部品８１を収めるためのキャビティを構成している。ビア電極２６は、絶縁体層１１を貫通することによって導電層２１と導電層２２とを互いに接続している。 The wiring board 90 has insulator layers 11 and 12 made of ceramic containing alumina as a main component, and conductive layers 21 to 23 provided on the insulator layers 11 and 12. The alumina content of the ceramic may be 70 wt% or more. Further, the ceramic may contain 10 to 30 wt% of zirconia for the purpose of increasing its strength. Further, the ceramic may contain several% of a glass component for the purpose of increasing the adhesion strength between the insulator layers 11 and 12 and the conductive layers 21 to 23. Further, the wiring board 90 may have a via electrode 26. In the configuration shown in FIG. 2, the conductive layer 21 is laminated on the lower surface of the insulator layer 11, and the conductive layer 22 and the insulator layer 12 are laminated on the upper surface of the insulator layer 11 to insulate. The conductive layer 23 is laminated on the upper surface of the body layer 12. The insulator layer 12 has a frame shape, and a region surrounded by the frame shape on the insulator layer 11 constitutes a cavity for accommodating the electronic component 81. The via electrode 26 connects the conductive layer 21 and the conductive layer 22 to each other by penetrating the insulator layer 11.
　上記積層体は、複数のグリーンシートの形成と、各グリーンシート上へのメタライズペーストの印刷と、これらグリーンシートの積層と、焼成と、によって形成され得る。グリーンシートが焼結することによって絶縁体層１１，１２が形成され、メタライズペーストが焼結することによって導電層２１～２３およびビア電極２６が形成される。メタライズペーストは、溶媒と、その中に分散された粉体とを有している。この粉体は、金属モリブデンの粉体と、金属タングステンの粉体とを含む。メタライズペーストはさらに、添加材の粉体を含んでいてよく、その組成は絶縁体層１１，１２の組成と類似していることが好ましい。 The laminate can be formed by forming a plurality of green sheets, printing a metallized paste on each green sheet, laminating these green sheets, and firing. Insulator layers 11 and 12 are formed by sintering the green sheet, and conductive layers 21 to 23 and via electrodes 26 are formed by sintering the metallized paste. The metallized paste has a solvent and a powder dispersed therein. This powder contains a powder of metallic molybdenum and a powder of metallic tungsten. The metallized paste may further contain a powder of the additive, preferably having a composition similar to that of the insulator layers 11 and 12.
　本実施の形態においては、配線基板９０はさらに、下地めっき層３１～３３（下地層）と、中間めっき層４１～４３と、Ａｕめっき層５１～５３（金層）とを有している。中間めっき層４１～４３は省略されてもよい。また本実施の形態においては、配線基板９０はさらに、ろう材部６１によって溶接された金属枠体６２を有している。 In the present embodiment, the wiring board 90 further has a base plating layer 31 to 33 (base layer), an intermediate plating layer 41 to 43, and an Au plating layer 51 to 53 (gold layer). The intermediate plating layers 41 to 43 may be omitted. Further, in the present embodiment, the wiring board 90 further has a metal frame body 62 welded by the brazing material portion 61.
　下地めっき層３１～３３のそれぞれは、導電層２１～２３上に直接的に設けられている。下地めっき層３１～３３は、金とは異なる導体からなり、好ましくはニッケルを含有しており、例えば、ニッケル、またはニッケルコバルト合金からなる。中間めっき層４１～４３は、金とは異なる導体からなり、好ましくはニッケルを含有しており、例えば、ニッケル、またはニッケルコバルト合金からなる。 Each of the base plating layers 31 to 33 is provided directly on the conductive layers 21 to 23. The base plating layers 31 to 33 are made of a conductor different from gold, preferably containing nickel, and are made of, for example, nickel or a nickel-cobalt alloy. The intermediate plating layers 41 to 43 are made of a conductor different from gold, preferably nickel-containing, and are made of, for example, nickel or a nickel-cobalt alloy.
　Ａｕめっき層５１は導電層２１上に少なくとも下地めっき層３１を介して設けられており、Ａｕめっき層５２は、導電層２２上に少なくとも下地めっき層３２を介して設けられており、Ａｕめっき層５３は導電層２３上に少なくとも下地めっき層３３を介して設けられている。具体的には、Ａｕめっき層５１は下地めっき層３１上に中間めっき層４１を介して設けられている。Ａｕめっき層５２は下地めっき層３２上に中間めっき層４２を介して設けられている。Ａｕめっき層５３は下地めっき層３３上に中間めっき層４３を介して設けられており、より具体的には、Ａｕめっき層５３は下地めっき層３３上に、ろう材部６１、金属枠体６２および中間めっき層４３を介して設けられている。 The Au plating layer 51 is provided on the conductive layer 21 at least via the base plating layer 31, and the Au plating layer 52 is provided on the conductive layer 22 via at least the base plating layer 32. 53 is provided on the conductive layer 23 via at least the base plating layer 33. Specifically, the Au plating layer 51 is provided on the base plating layer 31 via the intermediate plating layer 41. The Au plating layer 52 is provided on the base plating layer 32 via the intermediate plating layer 42. The Au plating layer 53 is provided on the base plating layer 33 via an intermediate plating layer 43. More specifically, the Au plating layer 53 is placed on the base plating layer 33 with a brazing material portion 61 and a metal frame 62. And is provided via an intermediate plating layer 43.
　金属枠体６２はろう材部６１によって下地めっき層３３に接合されている。金属枠体６２は中間めっき層４３を介してＡｕめっき層５３によって覆われている。めっき処理された金属枠体６２上に蓋８２が溶接されることになる。なお金属枠体６２は、金属からなり、この金属は合金であってよい。 The metal frame body 62 is joined to the base plating layer 33 by the brazing material portion 61. The metal frame 62 is covered with the Au plating layer 53 via the intermediate plating layer 43. The lid 82 will be welded onto the plated metal frame 62. The metal frame 62 is made of a metal, and this metal may be an alloy.
　図３は、導電層２１～２３（図２）の微細構造を模式的に示す断面図である。なお図３において、図を見やすくするために、被覆部７２は、ハッチングなしに白抜きで示されている。 FIG. 3 is a cross-sectional view schematically showing the fine structure of the conductive layers 21 to 23 (FIG. 2). In FIG. 3, the covering portion 72 is shown in white without hatching in order to make the figure easier to see.
　導電層２１～２３は、顕微鏡で観察可能な微細構造として、導電層２１～２３中に分散された複数のコア部７１と、これら複数のコア部７１の各々の表面を被覆する被覆部７２とを含む。導電層２１～２３の各々はさらに、顕微鏡で観察可能な微細構造として、アルミナを含有する添加材部７３を含むことが好ましく、その場合、共にアルミナを含有する導電層２１～２３と絶縁体層１１，１２との間の接合強度が高められる。添加材部７３は、ガラス成分を含有していてもよく、これにより導電層２１～２３の焼結が促進される。なお、被覆部７２は複数のコア部７１の各々の表面を完全に被覆することが好ましいが、これに限定されず、複数のコア部７１の一部が被覆部７２で被覆されずに露出してもよい。つまり、複数のコア部７１のうち大部分のコア部７１の表面が被覆部７２で被覆されていればよい。図３に示されるように数十個程度のコア部７１が含まれる視野内での観察例において、各コア部７１の外形線の長さの合計値に対して、各コア部７１の外形線のうち被覆部７２との境界線をなす部分の長さの合計値は、８０％以上であった。 The conductive layers 21 to 23 have a plurality of core portions 71 dispersed in the conductive layers 21 to 23 and a coating portion 72 that covers the surface of each of the plurality of core portions 71 as a microstructure that can be observed with a microscope. including. Each of the conductive layers 21 to 23 preferably further includes an alumina-containing additive portion 73 as a microstructure that can be observed with a microscope. In that case, both the conductive layers 21 to 23 and the insulator layer containing alumina are included. The joint strength between 11 and 12 is increased. The additive portion 73 may contain a glass component, which promotes sintering of the conductive layers 21 to 23. It is preferable that the covering portion 72 completely covers the surface of each of the plurality of core portions 71, but the present invention is not limited to this, and a part of the plurality of core portions 71 is exposed without being covered by the covering portion 72. You may. That is, it is sufficient that the surface of most of the core portions 71 among the plurality of core portions 71 is covered with the covering portion 72. As shown in FIG. 3, in an observation example in a field of view including several tens of core portions 71, the outline of each core portion 71 is relative to the total value of the outline lengths of each core portion 71. The total length of the portions forming the boundary line with the covering portion 72 was 80% or more.
　コア部７１は、モリブデン原子を含有しており、好ましくは８０ｗｔ％以上９５ｗｔ％以下のモリブデン濃度を有しており、実質的にモリブデンからなっていてよい。被覆部７２は、タングステン原子を含有しており、コア部７１に比して、より低いモリブデン濃度と、より高いタングステン濃度とを有している。 The core portion 71 contains a molybdenum atom, preferably has a molybdenum concentration of 80 wt% or more and 95 wt% or less, and may be substantially composed of molybdenum. The covering portion 72 contains a tungsten atom and has a lower molybdenum concentration and a higher tungsten concentration than the core portion 71.
　導電層２１～２３が含有するモリブデン原子を金属モリブデンとみなした場合のモリブデンの換算体積をＶＭと定義し、導電層２１～２３が含有するタングステン原子を金属タングステンとみなした場合のタングステンの換算体積をＶＷと定義し、これら換算体積ＶＭおよびＶＷの和を１００％と定義する。これら定義の下、換算体積ＶＷは２０％以上５０％以下の範囲にあることが好ましい。このような組成を得るためには、導電層２１～２３の材料であるメタライズペースト中において、金属モリブデンの粉体と金属タングステンの粉体とが、上記範囲を満たす体積比ＶＭ：ＶＷで混合されていればよい。図３に示された構造において、モリブデンとタングステンとの間での合金化は、あまり進行していないことが好ましく、合金化の影響を無視すれば、導電層２１～２３において、換算体積ＶＭはコア部７１の体積に対応し、換算体積ＶＷは被覆部７２の体積に対応する。なお導電層２１～２３中の金属成分は、実質的に、モリブデンおよびタングステンのみであってよい。 Molybdenum atoms conductive layers 21 to 23 contain the converted volume of molybdenum when regarded as metallic molybdenum is defined as V M, in terms of tungsten in the case where the conductive layers 21 to 23 is regarded as a tungsten atom and a metal tungsten containing the volume is defined as V W, defining the sum of these terms the volume V M and V W to 100%. Under these definitions, the converted volume V W is preferably in the range of 20% or more and 50% or less. To obtain such a composition, the metallized paste which is a material of the conductive layers 21 to 23, and the powder of the powder and metallic tungsten metal molybdenum, volume ratio satisfies the above range V M: at V W It suffices if it is mixed. In the structure shown in FIG. 3, the alloying between the molybdenum and tungsten is preferably not very advanced, ignoring the effect of alloying, the conductive layers 21 to 23, in terms of volume V M Corresponds to the volume of the core portion 71, and the converted volume V W corresponds to the volume of the covering portion 72. The metal components in the conductive layers 21 to 23 may be substantially only molybdenum and tungsten.
　＜効果＞
　本実施の形態によれば、相対的に高濃度にモリブデンを含有するコア部７１を導電層２１～２３が有することによって、配線基板９０の製造における焼成温度が低い場合であっても、導電層２１～２３が十分に焼結しやすくなる。これにより導電層２１～２３の十分な機械的強度が確保しやすい。また、相対的に高濃度にタングステンを含有する被覆部７２がコア部７１の各々の表面を覆うことによって、コア部７１の腐食が抑制される。以上から、焼成温度が低い場合であっても、高い機械的強度と、湿度および水分に対する高い耐腐食性とを有する導電層２１～２３を得ることができる。 <Effect>
According to the present embodiment, since the conductive layers 21 to 23 have the core portion 71 containing molybdenum at a relatively high concentration, the conductive layer is formed even when the firing temperature in the production of the wiring board 90 is low. 21 to 23 are sufficiently easy to sinter. As a result, it is easy to secure sufficient mechanical strength of the conductive layers 21 to 23. Further, the coating portion 72 containing tungsten in a relatively high concentration covers each surface of the core portion 71, so that the corrosion of the core portion 71 is suppressed. From the above, it is possible to obtain conductive layers 21 to 23 having high mechanical strength and high corrosion resistance against humidity and moisture even when the firing temperature is low.
　コア部７１は、８０ｗｔ％以上９５ｗｔ％以下のモリブデン濃度を有していることが好ましい。これにより、導電層２１～２３が、より焼結しやすくなる。当該濃度が８０ｗｔ％未満であると、相対的に被覆部７２のモリブデン濃度が高まる。この場合、被覆部７２自体の耐湿性が低下する。一方、当該濃度が９５ｗｔ％を超えると、コア部７１の耐湿性が低下する。この場合、コア部７１の表面のうち被覆部７２で被覆されていない部分が特に腐食されやすくなる。 The core portion 71 preferably has a molybdenum concentration of 80 wt% or more and 95 wt% or less. This makes it easier for the conductive layers 21 to 23 to sinter. When the concentration is less than 80 wt%, the molybdenum concentration of the covering portion 72 is relatively increased. In this case, the moisture resistance of the covering portion 72 itself is lowered. On the other hand, if the concentration exceeds 95 wt%, the moisture resistance of the core portion 71 decreases. In this case, the portion of the surface of the core portion 71 that is not covered with the covering portion 72 is particularly susceptible to corrosion.
　タングステンの換算体積ＶＷが２０％以上の場合、タングステンを含有する被覆部７２が、コア部７１の各々の表面を、より十分に被覆することができる。換算体積ＶＷが５０％以下の場合、モリブデンの換算体積ＶＭをより確保することができるので、導電層２１～２３の焼結を、より十分に進行させることができる。 When the converted volume V W of tungsten is 20% or more, the covering portion 72 containing tungsten can more sufficiently cover each surface of the core portion 71. If converted volume V W is less than 50%, can be more ensured converted volume V M of molybdenum, sintering of the conductive layers 21 to 23, it is possible to proceed more thoroughly.
　Ａｕめっき層５１～５３が導電層２１～２３に直接的に接合されたとすると、Ａｕめっき層５１～５３は容易に剥離する。よってＡｕめっき層５１～５３は、導電層２１～２３上に直接的に設けられた下地めっき層３１～３３を介して設けられることが好ましい。 Assuming that the Au plating layers 51 to 53 are directly bonded to the conductive layers 21 to 23, the Au plating layers 51 to 53 are easily peeled off. Therefore, it is preferable that the Au plating layers 51 to 53 are provided via the base plating layers 31 to 33 directly provided on the conductive layers 21 to 23.
　下地めっき層３１～３３はニッケルを含有していることが好ましい。この場合、下地めっき層３１～３３中のニッケルが導電層２１～２３中のタングステンまたはモリブデンと合金化することによって、導電層２１～２３へ下地めっき層３１～３３が強固に接合される。 It is preferable that the base plating layers 31 to 33 contain nickel. In this case, the nickel in the base plating layers 31 to 33 is alloyed with the tungsten or molybdenum in the conductive layers 21 to 23, so that the base plating layers 31 to 33 are firmly bonded to the conductive layers 21 to 23.
　配線基板９０は、下地めっき層３１～３３に接合されＡｕめっき層５１～５３によって覆われた金属枠体６２（図２）を含んでよい。金属枠体６２は、比較的厚い部材であることから、何らかの要因によって、図２における横方向から大きな外力を受ける可能性が比較的高い。また金属枠体６２は、大きな部材である蓋８２へ何らかの要因によって加わった力を、ほぼそのまま受けやすい。よって、金属枠体６２を支持している導電層２３へ大きな力が加わる可能性がある。そのような場合であっても、導電層２３へ下地めっき層３３が強固に接合していることによって、導電層２３上での剥離の発生が防止される。これにより、剥離に起因しての導電層２３上でのリークパスの発生が防止される。さらに、導電層２３の機械的強度が高いことによって、上述した大きな力に起因しての導電層２３の破壊も防止される。これにより、リークパスの発生が、より確実に防止される。 The wiring board 90 may include a metal frame 62 (FIG. 2) bonded to the base plating layers 31 to 33 and covered with Au plating layers 51 to 53. Since the metal frame 62 is a relatively thick member, there is a relatively high possibility that a large external force will be received from the lateral direction in FIG. 2 for some reason. Further, the metal frame body 62 is likely to receive a force applied to the lid 82, which is a large member, due to some factor, almost as it is. Therefore, a large force may be applied to the conductive layer 23 that supports the metal frame body 62. Even in such a case, since the base plating layer 33 is firmly bonded to the conductive layer 23, the occurrence of peeling on the conductive layer 23 is prevented. This prevents the occurrence of leak paths on the conductive layer 23 due to peeling. Further, the high mechanical strength of the conductive layer 23 prevents the conductive layer 23 from being destroyed due to the large force described above. As a result, the occurrence of leak paths is more reliably prevented.
　＜実験＞
　反射電子像を示す電子顕微鏡による断面写真（図４、図７、図９、図１１および図１３）と、２０倍率の光学顕微鏡による表面写真（図５、図６、図８、図１０、図１２および図１４）とを参照して、絶縁体層１１，１２に対応するアルミナ層（絶縁体層）１０上に、換算体積ＶＭおよびＶＷの比率が異なる導電層２０を形成することによって、複数種類の積層体（サンプル）を形成した。そしてその、湿度および水分に対する耐腐食性、具体的には耐酸化性、について検討を行った。 <Experiment>
A cross-sectional photograph (FIG. 4, FIG. 7, FIG. 9, FIG. 11, and FIG. 13) showing a reflected electron image and a surface photograph (FIG. 5, FIG. 6, FIG. 8, FIG. 10, FIG. 12 and with reference to FIG. 14) and, on the alumina layer (insulator layer) 10 corresponding to the insulating layers 11 and 12, by the ratio of the converted volume V M and V W to form a different conductive layer 20 , Multiple types of laminates (samples) were formed. Then, the corrosion resistance to humidity and moisture, specifically, the oxidation resistance was examined.
　はじめに、図４～図７を参照して、ＶＷ：ＶＭ＝０：１００のサンプルの実験結果について、以下に説明する。 First, with reference to FIGS. 4 to 7, V W: V M = 0: the 100 samples of the experimental results will be described below.
　図４は、初期状態（言い換えれば、酸化を促進しやすい環境にさらされる前の状態）における、観察の都合上Ｎｉめっき層４０が付されたサンプルの断面を示す。このサンプルにおいては、前述した実施の形態とは異なりタングステンが添加されていなかったので、コア部７１および添加材部７３が被覆部７２（図３）なしに分布していた。 FIG. 4 shows a cross section of a sample to which the Ni plating layer 40 is attached for convenience of observation in the initial state (in other words, the state before being exposed to an environment that easily promotes oxidation). In this sample, unlike the above-described embodiment, tungsten was not added, so that the core portion 71 and the additive portion 73 were distributed without the coating portion 72 (FIG. 3).
　図５は、初期状態における、めっき層なしのサンプルの表面を示す。２０倍率の光学顕微鏡による導電層２０の表面像はほぼ白色を呈し、これは導電層２０が未だ酸化されていなかったことを示す。図６は、上記サンプルの、高温高湿試験後における表面を示す。なお、本明細書に記載する高温高湿試験は、温度８５℃、相対湿度８５％、期間９６時間の条件で行われた。２０倍率の光学顕微鏡による導電層２０の表面像はほぼ黒色を呈し、これは導電層２０がかなり酸化されていたことを示す。 FIG. 5 shows the surface of the sample without the plating layer in the initial state. The surface image of the conductive layer 20 by a 20-magnification optical microscope is almost white, indicating that the conductive layer 20 has not yet been oxidized. FIG. 6 shows the surface of the sample after the high temperature and high humidity test. The high temperature and high humidity test described in the present specification was performed under the conditions of a temperature of 85 ° C., a relative humidity of 85%, and a period of 96 hours. The surface image of the conductive layer 20 by a 20-magnification optical microscope was substantially black, indicating that the conductive layer 20 was considerably oxidized.
　図７は、Ｎｉめっき層４０およびＡｕめっき層５０が付されたサンプルの、プレッシャークッカー試験（ＰＣＴ）後における断面を、導電層２０の端（破線ＥＤで示された位置）近傍で示す。ＰＣＴは、温度１２１℃、相対湿度１００％、圧力２ａｔｍ、期間１０００時間の条件で行われた。破線ＥＤ（図７）のすぐ左側において、導電層２０の端部とＮｉめっき層４０との界面に異常がみられた。これは腐食が発生したことを示している。 FIG. 7 shows a cross section of the sample with the Ni plating layer 40 and the Au plating layer 50 after the pressure cooker test (PCT) near the end of the conductive layer 20 (the position indicated by the broken line ED). The PCT was performed under the conditions of a temperature of 121 ° C., a relative humidity of 100%, a pressure of 2 atm, and a period of 1000 hours. Immediately to the left of the broken line ED (FIG. 7), an abnormality was observed at the interface between the end of the conductive layer 20 and the Ni plating layer 40. This indicates that corrosion has occurred.
　以上、図４～図７の結果から、ＶＷ：ＶＭ＝０：１００のサンプルは湿度および水分に対する耐腐食性が低いことがわかった。 Above, from the results of FIGS. 4 to 7, V W: V M = 0: 100 of the samples were found to be less corrosion resistance to humidity and moisture.
　次に、図８を参照して、ＶＷ：ＶＭ＝１００：０のサンプルの実験結果について説明する。この図８は、めっき層なしのサンプルの、高温高湿試験後における表面を示す。２０倍率の光学顕微鏡による導電層２０の表面像はほぼ白色を呈し、これは導電層２０がほとんど酸化されていなかったことを示す。よって、ＶＷ：ＶＭ＝１００：０の場合、湿度および水分に対する耐腐食性が高いことがわかった。一方でこのサンプルの導電層２０は、モリブデンを含有していないので、低い機械的強度しか有していなかった。 Next, with reference to FIG. 8, V W: V M = 100: 0 Sample experimental results will be described. FIG. 8 shows the surface of a sample without a plating layer after a high temperature and high humidity test. The surface image of the conductive layer 20 by a 20-magnification optical microscope was almost white, indicating that the conductive layer 20 was hardly oxidized. Therefore, V W: V M = 100 : 0, it was found that higher corrosion resistance to humidity and moisture. On the other hand, since the conductive layer 20 of this sample does not contain molybdenum, it has only low mechanical strength.
　次に、図９および図１０を参照して、ＶＷ：ＶＭ＝３５：６５のサンプルの実験結果について、以下に説明する。図９は、初期状態における、観察の都合上Ｎｉめっき層４０が付されたサンプルの断面を示す。このサンプルにおいては、前述した実施の形態において図３を参照して説明したように、コア部７１（図９における導電層２０のグレー部）と、被覆部７２（図９における導電層２０の白色部）と、添加材部７３（図９における導電層２０の黒色部）とが分布しており、コア部７１の各々の表面を被覆部７２がほぼ完全に被覆していた。図１０は、めっき層なしのサンプルの、高温高湿試験後における表面を示す。２０倍率の光学顕微鏡による導電層２０の表面像は、図６に比して、より白色に近い明るい色を呈した。これは、ＶＷ：ＶＭ＝０：１００の場合に比して、ＶＷ：ＶＭ＝３５：６５の場合の方が、導電層２０の酸化が抑制されたことを示す。 Next, with reference to FIGS. 9 and 10, V W: V M = 35: For a sample of experimental results 65 will be described below. FIG. 9 shows a cross section of a sample to which the Ni plating layer 40 is attached for convenience of observation in the initial state. In this sample, as described with reference to FIG. 3 in the above-described embodiment, the core portion 71 (gray portion of the conductive layer 20 in FIG. 9) and the covering portion 72 (white portion of the conductive layer 20 in FIG. 9) The portion) and the additive portion 73 (the black portion of the conductive layer 20 in FIG. 9) were distributed, and the coating portion 72 almost completely covered the surface of each of the core portions 71. FIG. 10 shows the surface of a sample without a plating layer after a high temperature and high humidity test. The surface image of the conductive layer 20 by a 20-magnification optical microscope exhibited a bright color closer to white as compared with FIG. This, V W: compared with the case of 100, V W:: V M = 0 V M = 35: 65 is more in the case of indicating that the oxidation of the conductive layer 20 is suppressed.
　次に、図１１および図１２を参照して、ＶＷ：ＶＭ＝５０：５０のサンプルの実験結果について、以下に説明する。図１１は、初期状態における、観察の都合上Ｎｉめっき層４０が付されたサンプルの断面を示す。このサンプルにおいても、コア部７１の各々の表面を被覆部７２がほぼ完全に被覆していた。図１２は、めっき層なしのサンプルの、高温高湿試験後における表面を示す。２０倍率の光学顕微鏡による導電層２０の表面像は、図６に比して、より白色に近い明るい色を呈した。これは、ＶＷ：ＶＭ＝０：１００の場合に比して、ＶＷ：ＶＭ＝５０：５０の場合の方が、導電層２０の酸化が抑制されたことを示す。 Next, with reference to FIGS. 11 and 12, V W: V M = 50: Experimental results of 50 samples will be described below. FIG. 11 shows a cross section of a sample to which the Ni plating layer 40 is attached for convenience of observation in the initial state. Also in this sample, the coating portion 72 almost completely covered each surface of the core portion 71. FIG. 12 shows the surface of the sample without the plating layer after the high temperature and high humidity test. The surface image of the conductive layer 20 by a 20-magnification optical microscope exhibited a bright color closer to white as compared with FIG. This, V W: compared with the case of 100, V W:: V M = 0 V M = 50: 50 is more in the case of indicating that the oxidation of the conductive layer 20 is suppressed.
　次に、図１３および図１４を参照して、ＶＷ：ＶＭ＝２０：８０のサンプルの実験結果について、以下に説明する。図１３は、初期状態における、観察の都合上Ｎｉめっき層４０が付されたサンプルの断面を示す。このサンプルにおいては、コア部７１の各々の表面を被覆部７２がおおよそ被覆していた。ただし図９および図１１の各々のサンプルと比べると、コア部７１の表面が露出しかけているようにみえる部分があった。画像解析ソフトＩｍａｇｅＪを用いて図１３の画像解析を行った結果、各コア部７１の外形線の長さの合計値に対して、各コア部７１の外形線のうち被覆部７２との境界線をなす部分の長さの合計値は、８０％以上であった。図１４は、めっき層なしのサンプルの、高温高湿試験後における表面を示す。２０倍率の光学顕微鏡によるこのサンプルの導電層２０の表面像は、図１０および図１２の各々のサンプルと比べると若干黒色に近くなり暗いものの、図６に比べれば、より白色に近い明るい色を呈した。これは、ＶＷ：ＶＭ＝０：１００の場合に比して、ＶＷ：ＶＭ＝２０：８０の場合の方が、導電層２０の酸化が抑制されたことを示す。 Next, with reference to FIGS. 13 and 14, V W: V M = 20: for 80 samples of experimental results will be described below. FIG. 13 shows a cross section of a sample to which the Ni plating layer 40 is attached for convenience of observation in the initial state. In this sample, the coating portion 72 roughly covered each surface of the core portion 71. However, as compared with the samples of FIGS. 9 and 11, there was a portion where the surface of the core portion 71 seemed to be exposed. As a result of performing the image analysis of FIG. 13 using the image analysis software ImageJ, the boundary line between the outer line of each core portion 71 and the covering portion 72 is relative to the total value of the lengths of the outer lines of each core portion 71. The total length of the portions forming the sword was 80% or more. FIG. 14 shows the surface of a sample without a plating layer after a high temperature and high humidity test. The surface image of the conductive layer 20 of this sample by a 20-magnification optical microscope is slightly blacker and darker than the samples of FIGS. 10 and 12, but has a brighter color closer to white than that of FIG. Presented. This, V W: compared with the case of 100, V W:: V M = 0 V M = 20: 80 is more in the case of indicating that the oxidation of the conductive layer 20 is suppressed.
　一般に原子番号が大きいほど反射電子の信号強度は大きいので、反射電子像は白色度が高くなる。このことから、図１３において、グレー部であるコア部７１はモリブデン濃度が高く、白色部である被覆部７２はタングステン濃度が高いと推定される。 Generally, the higher the atomic number, the higher the signal strength of the reflected electron, so the reflected electron image has a higher whiteness. From this, it is estimated that in FIG. 13, the core portion 71, which is a gray portion, has a high molybdenum concentration, and the coating portion 72, which is a white portion, has a high tungsten concentration.
　上記推定を検証するために、反射電子像の観察と共に、ＥＤＸ（Ｅｎｅｒｇｙ－Ｄｉｓｐｅｒｓｉｖｅ　Ｘ－Ｒａｙ　Ｓｐｅｃｔｒｏｍｅｔｒｙ）を行った。観察サンプルの断面はイオンミリングで製作され、その上にカーボン蒸着が行われた。反射電子像の観察のためには日立ハイテクノロジーズ製Ｓ－３４００Ｎが用いられた。ＥＤＸにはＥＤＡＸ製ＧｅｎｅｓｉｓＭＸ４が用いられた。ＥＤＸにおける加速電圧は１０ｋＶであり、測定視野範囲における１５０秒間の走査によって信号強度が計測された。 In order to verify the above estimation, EDX (Energy-Dispersive X-Ray Spectrometry) was performed together with the observation of the reflected electron image. The cross section of the observation sample was made by ion milling, and carbon vapor deposition was performed on it. Hitachi High-Technologies S-3400N was used for observing the backscattered electron image. Genesis MX4 manufactured by EDAX was used for EDX. The acceleration voltage in EDX was 10 kV, and the signal strength was measured by scanning for 150 seconds in the measurement field of view.
　図１５～図１７は、図９と同様にＶＷ：ＶＭ＝３５：６５の組成比を有するサンプルについての分析結果である。ただしこのサンプルは、観察の都合上、図９のサンプルとは別個に準備された。図１５は、初期状態における、Ｎｉめっき層４０（図９参照）が付されていない当該サンプルの断面の反射電子像を示す。図１６は、図１５と同一視野におけるモリブデン濃度の分布をＥＤＸで測定した結果を示す。図１７は、図１５と同一視野におけるタングステン濃度の分布をＥＤＸで測定した結果を示す。導電層の視野範囲は約２４μｍ×約１２μｍであった。図１５～図１７における矢印１は、コア部７１の位置を示している。同様に、矢印２は、被覆部７２の位置を示している。 15 to 17 are similarly V W and Figure 9: V M = 35: the analysis results for the samples having a composition ratio of 65. However, this sample was prepared separately from the sample shown in FIG. 9 for convenience of observation. FIG. 15 shows a reflected electron image of a cross section of the sample without the Ni plating layer 40 (see FIG. 9) in the initial state. FIG. 16 shows the results of measuring the distribution of molybdenum concentration in the same field of view as in FIG. 15 with EDX. FIG. 17 shows the result of measuring the distribution of the tungsten concentration in the same field of view as in FIG. 15 with EDX. The visual field range of the conductive layer was about 24 μm × about 12 μm. Arrow 1 in FIGS. 15 to 17 indicates the position of the core portion 71. Similarly, the arrow 2 indicates the position of the covering portion 72.
　図１６に示されたＥＤＸ測定においては、白色度が高いほどモリブデン濃度が高い。矢印１で示されるコア部７１よりも矢印２で示される被覆部７２の方が白色度が低いので、コア部７１よりも被覆部７２の方がモリブデン濃度が低いと言える。 In the EDX measurement shown in FIG. 16, the higher the whiteness, the higher the molybdenum concentration. Since the coating portion 72 indicated by the arrow 2 has a lower whiteness than the core portion 71 indicated by the arrow 1, it can be said that the coating portion 72 has a lower molybdenum concentration than the core portion 71.
　図１７に示されたＥＤＸ測定においては、白色度が高いほどタングステン濃度が高い。矢印１で示されるコア部７１よりも矢印２で示される被覆部７２の方が白色度が高いので、コア部７１よりも被覆部７２の方がタングステン濃度が高いと言える。 In the EDX measurement shown in FIG. 17, the higher the whiteness, the higher the tungsten concentration. Since the covering portion 72 indicated by the arrow 2 has a higher whiteness than the core portion 71 indicated by the arrow 1, it can be said that the covering portion 72 has a higher tungsten concentration than the core portion 71.
　次に、コア部７１の中心部付近に電子ビームを照射することで、ＥＤＸによってコア部７１の元素濃度が計測された。具体的には、位置の異なるコア部が任意で３つ選択され、そのそれぞれの中心部付近の位置Ａ～Ｃで計測がなされた。その結果を、以下の表１に示す。 Next, the element concentration of the core portion 71 was measured by EDX by irradiating the vicinity of the central portion of the core portion 71 with an electron beam. Specifically, three core portions having different positions were arbitrarily selected, and measurements were taken at positions A to C near the center of each. The results are shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　この計測結果から、コア部におけるモリブデン濃度は８０ｗｔ％～９５ｗｔ％であることが分かった。また、この計測と同様の計測が、図１１のサンプルと同じくＶＷ：ＶＭ＝５０：５０の比を有するサンプルと、図１３のサンプルと同じくＶＷ：ＶＭ＝２０：８０の比を有するサンプルとに対しても行われ、その結果は表１と同様であった。 From this measurement result, it was found that the molybdenum concentration in the core portion was 80 wt% to 95 wt%. Moreover, this measurement similar to the measurement, like V W and Sample 11: a sample having a 50 ratio, sample Like V W in Figure 13:: V M = 50 V M = 20: 80 ratio of It was also performed with the sample to have, and the result was the same as in Table 1.
　コア部７１のモリブデン濃度が８０ｗｔ％未満である場合、相対的に被覆部７２のモリブデン濃度が高まる。この場合、被覆部７２自体の耐湿性が低下し、図６に示されるように、高温高湿試験後に酸化腐食が進行するおそれがある。一方、コア部７１のモリブデン濃度が９５ｗｔ％を超える場合、コア部７１の耐湿性が低下する。この場合、コア部７１の表面のうち被覆部７２で被覆されていない部分において高温高湿試験後に、図６に示されるように、特に酸化腐食が進行するおそれがある。 When the molybdenum concentration of the core portion 71 is less than 80 wt%, the molybdenum concentration of the coating portion 72 is relatively high. In this case, the moisture resistance of the covering portion 72 itself is lowered, and as shown in FIG. 6, oxidative corrosion may proceed after the high temperature and high humidity test. On the other hand, when the molybdenum concentration of the core portion 71 exceeds 95 wt%, the moisture resistance of the core portion 71 is lowered. In this case, as shown in FIG. 6, oxidative corrosion may particularly progress after the high temperature and high humidity test on the portion of the surface of the core portion 71 that is not covered by the coating portion 72.
　次に、電子ビームが図１５の導体層２０の全面へ照射されつつ、ＥＤＸによって元素濃度が計測された。その結果、タングステンとモリブデンとの重量パーセントの比率は、導体層２０の材料であるメタライズペースト中における、金属モリブデンと金属タングステンの重量パーセントの比率とほぼ一致していた。 Next, the element concentration was measured by EDX while irradiating the entire surface of the conductor layer 20 of FIG. 15 with an electron beam. As a result, the weight percent ratio of tungsten to molybdenum was substantially the same as the weight percent ratio of metal molybdenum to metal tungsten in the metallized paste which is the material of the conductor layer 20.
　この発明は詳細に説明されたが、上記した説明は、すべての態様において、例示であって、この発明がそれに限定されるものではない。例示されていない無数の変形例が、この発明の範囲から外れることなく想定され得るものと解される。 Although the present invention has been described in detail, the above description is exemplary in all embodiments and the invention is not limited thereto. It is understood that innumerable variations not illustrated can be assumed without departing from the scope of the present invention.
　１０　　　：アルミナ層（絶縁体層）
　１１，１２：絶縁体層
　２０～２３：導電層
　２６　　　：ビア電極
　３１～３３：下地めっき層（下地層）
　４０　　　：Ｎｉめっき層
　４１～４３：中間めっき層
　５０～５３：Ａｕめっき層（金層）
　６１　　　：ろう材部
　６２　　　：金属枠体
　７１　　　：コア部
　７２　　　：被覆部
　７３　　　：添加材部
　８１　　　：電子部品
　８２　　　：蓋
　９０　　　：配線基板 10: Alumina layer (insulator layer)
11, 12: Insulator layer 20 to 23: Conductive layer 26: Via electrode 31 to 33: Base plating layer (base layer)
40: Ni plating layer 41 to 43: Intermediate plating layer 50 to 53: Au plating layer (gold layer)
61: Wax material part 62: Metal frame body 71: Core part 72: Coating part 73: Additive material part 81: Electronic parts 82: Lid 90: Wiring board

Claims (6)

  1. 　アルミナを含有するセラミックからなる絶縁体層と、
    　前記絶縁体層上に設けられた導電層と、
    を備え、前記導電層は、
    　　前記導電層中に分散されモリブデンを含有する複数のコア部と、
    　　前記複数のコア部の各々の表面を被覆しタングステンを含有する被覆部と、
    を含み、前記被覆部は前記コア部に比して、より低いモリブデン濃度と、より高いタングステン濃度とを有している、配線基板。     An insulator layer made of ceramic containing alumina,
    The conductive layer provided on the insulator layer and
    The conductive layer is provided with
    A plurality of core portions dispersed in the conductive layer and containing molybdenum,
    A covering portion that covers the surface of each of the plurality of core portions and contains tungsten,
    A wiring board, wherein the covering portion has a lower molybdenum concentration and a higher tungsten concentration as compared with the core portion.
  2. 　前記コア部は、８０重量パーセント以上９５重量パーセント以下のモリブデン濃度を有している、請求項１に記載の配線基板。 The wiring board according to claim 1, wherein the core portion has a molybdenum concentration of 80% by weight or more and 95% by weight or less.
  3. 　前記導電層が含有するモリブデン原子を金属モリブデンとみなした場合のモリブデン体積をＶＭと定義し、前記導電層が含有するタングステン原子を金属タングステンとみなした場合のタングステン体積をＶＷと定義し、ＶＭおよびＶＷの和を１００パーセントと定義すると、ＶＷは２０パーセント以上５０パーセント以下である、請求項１または２に記載の配線基板。 The molybdenum volume when the conductive layer is regarded as a molybdenum atoms containing a molybdenum metal is defined as V M, tungsten volume of when the conductive layer is regarded as a tungsten atoms containing a metal tungsten is defined as V W, When defining the sum of V M and V W and 100%, V W is less than 50 percent over 20 percent, the wiring board according to claim 1 or 2.
  4. 　前記導電層上に直接的に設けられ、金とは異なる導体からなる下地層と、
    　前記導電層上に少なくとも前記下地層を介して設けられた金層と、
    をさらに備える、請求項１から３のいずれか１項に記載の配線基板。     A base layer provided directly on the conductive layer and made of a conductor different from gold,
    A gold layer provided on the conductive layer at least via the base layer, and
    The wiring board according to any one of claims 1 to 3, further comprising.
  5. 　前記下地層はニッケルを含有している、請求項４に記載の配線基板。 The wiring board according to claim 4, wherein the base layer contains nickel.
  6. 　前記下地層に接合され、前記金層によって覆われた金属枠体をさらに備える、請求項４または５に記載の配線基板。 The wiring board according to claim 4 or 5, further comprising a metal frame bonded to the base layer and covered with the gold layer.
PCT/JP2020/045787 2019-12-26 2020-12-09 Wiring board WO2021131693A1 (en)

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TW202133698A (en) 2021-09-01
JP7001876B2 (en) 2022-01-20
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TWI753709B (en) 2022-01-21
CN114026968B (en) 2022-08-30

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