JP2006073280A - Metalized composition and ceramic wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metalized composition capable of forming a conductive layer having a predetermined shape and size, even if it is a low-melting-point conductive material; and to provide a ceramic wiring board equipped with a conductive layer that uses it. <P>SOLUTION: This metalized composition contains a low-melting-point metal such as Cu and a metal compound, such as WC; and when it is assumed that the total of the low-melting point metal and the metal compound is 100 vol.%, the content of the metal compound is 33-72 vol.%. This ceramic wiring board 1 comprises a ceramic part 11 (formed of alumina or the like) and a conductive layer 12 disposed on a surface thereof or in the inside thereof; and the conductive layer comprises a low-melting-point metal part (formed of Cu or the like) formed of a low-melting-point metal, having a melting point lower than the sintering temperature of a ceramic material constituting the ceramic part, and a metal compound junction part (formed of WC or the like), formed in the low-melting-point metal part and formed of a metal compound having a melting point higher than the sintering temperature of the ceramic material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metallized composition and a ceramic wiring board. More specifically, the present invention can form a conductor layer such as a wiring pattern having a predetermined shape and dimensions by holding a molten low melting point metal by a metal compound at the time of co-firing with an unfired ceramic substrate. In addition, the present invention relates to a metallized composition capable of sufficiently adhering the conductor layer and the ceramic substrate, and a ceramic wiring board provided with a conductor layer using the metallized composition.

  In recent years, with the increase in speed and integration of electronic components, ceramic wiring substrates such as multilayer wiring substrates on which semiconductor components are mounted are required to have high strength, high thermal conductivity, and low loss. Moreover, it is preferable that the conductor layer with which a ceramic wiring board is provided is low resistance.

  Conventionally, in a circuit board, a package, and the like provided with an insulator made of a ceramic material fired at a high temperature such as alumina, a refractory metal such as W and Mo is used as an internal conductor layer and a surface conductor layer. This is because the melting points of these metals are higher than, for example, the sintering temperature of alumina and can be fired simultaneously. However, the specific resistance value of the conductor layer formed using W is usually 20 μΩ · cm or more. On the other hand, when Cu is used, the specific resistance value of the conductor layer can be set to 5 μΩ · cm or less. Low resistance to W, Mo and the like. Therefore, also in the case of a ceramic material fired at a high temperature such as alumina, a method of simultaneously firing this ceramic material and Cu has been proposed (see, for example, Patent Document 1 and Patent Document 2).

JP-A-4-124071 JP-A-7-15101

  However, the melting point of a low-resistance metal material such as Cu is lower than the sintering temperature of a ceramic material fired at a high temperature such as alumina, and when these are co-fired, the molten Cu flows and the unfired alumina sheet And the like, the shape retention of the conductor layer such as the formed wiring pattern is reduced. Further, in the method described in Patent Document 1 and Patent Document 2, the conductor layer made of Cu or the like is sealed inside the unfired alumina molded body, that is, co-fired without being exposed to the surface, When the wiring is exposed on the surface, polishing or the like is necessary, and the yield tends to decrease and the cost tends to increase.

  The present invention solves the above-mentioned conventional problems, and in the simultaneous firing with the unfired ceramic substrate, the molten low-melting point metal is held by the metal compound, and a wiring pattern having a predetermined shape and size is obtained. To provide a metallized composition capable of forming a conductor layer and sufficiently adhering the conductor layer and the ceramic substrate, and a ceramic wiring board provided with a conductor layer using the metallized composition. Objective.

The present invention is as follows.
1. A low melting point metal mainly composed of at least one of Cu, Ag and Au, and a metal compound mainly composed of at least one of metal carbide, metal nitride, metal boride and metal silicide. A metallized composition containing the metal compound in an amount of 33 to 72% by volume when the total of the low melting point metal and the metal compound is 100% by volume.
2. 1. The volume resistivity of the metal compound is 45 × 10 ⁻⁸ Ω · m or less. Metallized composition as described in 2.
3. The low melting point metal is mainly composed of Cu, and the metal compound is composed mainly of WC. Or 2. Metallized composition as described in 2.
4). When the total of the low melting point metal and the metal compound is 100% by mass, the low melting point metal is 18.0 to 53.5% by mass. Metallized composition as described in 2.
5. In a ceramic wiring board comprising a ceramic substrate and a conductor layer disposed on or inside the ceramic substrate, the conductor layer has a melting point higher than the firing temperature of the ceramic material that constitutes the ceramic substrate by firing. A low melting point metal part composed of a low melting point metal, and a ceramic material formed in the low melting point metal part, the main component being at least one of metal carbide, metal nitride, metal boride and metal silicide. And a metal compound connecting portion made of a metal compound having a melting point higher than the firing temperature of the ceramic wiring board.
6). 4. The volume resistivity of the metal compound is 45 × 10 ⁻⁸ Ω · m or less. Metallized composition as described in 2.
7). The metal compound connecting portion is formed by bringing particles made of the metal compound into contact with each other. The ceramic wiring board according to 1.
8). 5. The low melting point metal is mainly composed of at least one of Cu, Ag and Au. Or 7. The ceramic wiring board according to 1.
9. A ceramic wiring board comprising a ceramic substrate and a conductor layer disposed on or inside the ceramic substrate, wherein the conductor layer is a low melting point metal mainly comprising at least one of Cu, Ag and Au. And a metal compound mainly composed of at least one of metal carbide, metal nitride, metal boride and metal silicide, and the total of the low melting point metal and the metal compound is 100% by volume. In this case, the content of the metal compound is 33 to 72% by volume.
10. 8. The volume resistivity of the metal compound is 45 × 10 ⁻⁸ Ω · m or less. Metallized composition as described in 2.
11. 5. The low melting point metal is mainly composed of Cu, and the metal compound is composed mainly of WC. 7. 9. Or 10. The ceramic wiring board according to 1.

According to the metallized composition of the present invention, the molten low melting point metal is held by the metal compound during the simultaneous firing with the unfired ceramic substrate, thereby forming a conductor layer such as a wiring pattern having a predetermined shape and size. And the conductor layer and the ceramic substrate can be sufficiently adhered to each other.
Further, when the volume resistivity of the metal compound is 45 × 10 ⁻⁸ Ω · m or less, a conductor layer having a sufficiently low resistance can be obtained.
Further, when the low melting point metal is mainly composed of Cu and the metal compound is mainly composed of WC, the molten low melting point metal is sufficiently held by the metal compound, and a conductor layer having a predetermined shape and size can be more easily formed. Can be formed.
When the total of the low melting point metal mainly composed of Cu and the metal compound mainly composed of WC is 100% by mass, the low melting point metal is 18.0 to 53.5% by mass. The molten low melting point metal is sufficiently held by the metal compound, has a predetermined shape and size, can be a low resistance conductor layer, and the conductor layer and the ceramic substrate can be sufficiently adhered to each other. it can.
According to the ceramic wiring board of the present invention in which the conductor layer includes the low melting point metal portion and the metal compound connecting portion, the conductor layer has a conductor layer such as a wiring pattern of a predetermined shape and size, and the conductor layer and the ceramic base are It is possible to provide a sufficiently closely connected wiring board, and thinning is easy.
Furthermore, when the volume resistivity of the metal compound is 45 × 10 ⁻⁸ Ω · m or less, a wiring substrate having a sufficiently low resistance conductor layer can be obtained.
Further, when the metal compound connecting portion is formed by contacting particles made of a metal compound, a low melting point metal portion without a portion where the low melting point metal is discontinuous is formed, and has a predetermined shape and size. A wiring board having a conductor layer can be obtained.
Furthermore, when the low melting point metal is mainly composed of at least one of Cu, Ag and Au, a wiring board having a sufficiently low resistance conductor layer can be obtained.
According to another ceramic wiring substrate of the present invention in which the metal layer is 33 to 72% by volume when the conductor layer contains a low melting point metal and a metal compound and the total of these is 100% by volume, The molten low melting point metal is sufficiently held by the metal compound, has a conductor layer having a predetermined shape and size, and can be a wiring board in which the conductor layer and the ceramic substrate are sufficiently adhered.
Moreover, when the volume resistivity of the metal compound is 45 × 10 ⁻⁸ Ω · m or less, a wiring substrate having a sufficiently low resistance conductor layer can be obtained.
Further, in the ceramic wiring board of the present invention and the other ceramic wiring board of the present invention, when the low melting point metal is mainly composed of Cu and the metal compound is composed mainly of WC, the molten low melting point metal is the metal compound. Therefore, the conductor layer can be a conductor layer having a predetermined shape and size and a low resistance, and the conductor layer and the ceramic substrate can be sufficiently adhered to each other.

Hereinafter, the present invention will be described in detail.
[1] Metallized Composition The “low melting point metal” contains at least one of Cu, Ag and Au as a main component. The phrase “consisting mainly of at least one” means that when only one of Cu, Ag, and Au is contained, the content of this one is 100% by mass of the entire low-melting-point metal. In addition, it means 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more (may be 100% by mass). Further, when two or more of Cu, Ag, and Au are contained, the total content is 80% by mass or more, preferably 90% by mass or more, when the entire low-melting point metal is 100% by mass. More preferably, it means 95% by mass or more (may be 100% by mass). Cu, Ag, and Au may each be a simple substance or an alloy containing each metal. In the case of an alloy, this alloy may contain only one of Cu, Ag and Au, or may contain two or more. Furthermore, when other metals except Cu, Ag, and Au are contained in the low melting point metal, the other metals are not particularly limited, and examples thereof include Al, Ni, Zn, Sn, and Mn. The content of the other metal is 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less when the entire low-melting point metal is 100% by mass.

  The melting point of the low-melting point metal is the melting point of each of Cu, Ag, and Au. When the low melting point metal contains a plurality of metals, the melting point is not particularly limited, but is usually 1200 ° C. or lower, preferably 1150 ° C. or lower, more preferably 1100 ° C. or lower (usually 900 ° C. or higher). .

  Furthermore, an unsintered ceramic layer in which the unsintered conductor layer is disposed is formed into an unsintered conductor layer (fired to become a conductor layer such as a wiring pattern or a heater pattern) formed using the metallized composition of the present invention. When co-firing with a substrate (fired to become a ceramic substrate), the melting point of the low melting point metal is lower than the firing temperature of the ceramic material used to form the unfired ceramic substrate. That is, when the ceramic material is an alumina-based sintered body, the melting point of the low melting point metal is preferably 1300 ° C. or lower, particularly 1100 ° C. or lower (usually 800 ° C. or higher). In the case of a zirconia-based sintered body, the low melting point metal preferably has a melting point of 1300 ° C. or lower, particularly 1000 ° C. or lower (usually 800 ° C. or higher).

  The form of the low-melting-point metal in the metallized composition is not particularly limited, and may be solid or liquid like an organometallic compound. This low-melting-point metal is usually in a solid form, particularly in a powder form. That is, it is contained as a low melting point metal powder. The shape and dimensions of the low melting point metal powder are not particularly limited. The shape of the powder may be spherical, ellipsoidal, scale-like, or needle-like, or may be a mixture of powders of these shapes. Moreover, the average particle diameter of the powder (assuming that it is the average value of the maximum dimension when not spherical) is 0.5 to 8 μm, preferably 1 to 5 μm, more preferably 1.5 to 4 μm. When the average particle diameter is within this range, the shape retention of the conductor layer formed of the metallized composition can be improved.

  The “metal compound” is at least one of metal carbide, metal nitride, metal boride and metal silicide. These metal compounds may be used alone or in combination of two or more.

The melting point of this metal compound is higher than that of the low melting point metal. That is, the melting point of the metal compound exceeds 1300 ° C, preferably exceeds 1700 ° C, more preferably exceeds 3000 ° C.
Furthermore, when the unfired conductor layer formed using the metallized composition of the present invention is co-fired with the unfired ceramic substrate on which the unfired conductor layer is disposed, the melting point of the metal compound is such that the unfired ceramic substrate Higher than the firing temperature of the ceramic material used to fabricate That is, when the ceramic material is an alumina-based sintered body, the melting point of the metal compound is 1700 ° C. or higher, particularly 3000 ° C. or higher (usually 3500 ° C. or lower). Moreover, also when it is a zirconia group sintered compact, melting | fusing point of a metal compound is 1700 degreeC or more, Especially 3000 degreeC or more (usually 3500 degrees C or less).

Furthermore, the volume resistivity of the metal compound is preferably 45 × 10 ⁻⁸ Ω · m or less. The volume resistivity is more preferably 30 × 10 ⁻⁸ Ω · m or less, and particularly preferably 20 × 10 ⁻⁸ Ω · m or less. When the volume resistivity of the metal compound is 45 × 10 ⁻⁸ Ω · m or less, a conductor layer having a sufficiently low resistance can be obtained, and a wiring board having a conductor layer having a low resistance can be obtained.

Examples of the “metal carbide” include WC (2865 ° C., 19 × 10 ⁻⁸ Ω · m), TaC (3880 ° C., 22 × 10 ⁻⁸ Ω · m), NbC (3900 ° C., 44 × 10 ⁻⁸ Ω · m). m), HfC (3887 ° C., 39 × 10 ⁻⁸ Ω · m), ZrC (3540 ° C., 49 × 10 ⁻⁸ Ω · m), TiC (about 3200 ° C., 61 × 10 ⁻⁸ Ω · m), etc. Can be mentioned. Of these, WC, TaC and NbC, which have a high melting point and a small volume resistivity, are preferred. Further, WC and TaC are more preferable, and WC is particularly preferable. Only one metal carbide may be used, or two or more metal carbides may be used.

As the “metal nitride”, TiN (2950 ° C., 40 × 10 ⁻⁸ Ω · m), ZrN (2700 ° C., 18 × 10 ⁻⁸ Ω · m), HfN (3000 ° C., 32 × 10 ⁻⁸ Ω) M) and NbN (2573 ° C., 54 × 10 ⁻⁸ Ω · m). Among these, TiN and ZrN having a high melting point and a small volume resistivity are preferable, and TiN is more preferable. Only one metal nitride may be used, or two or more metal nitrides may be used.

Examples of the “metal boride” include TiB ₂ (2900 ° C., 9 × 10 ⁻⁸ Ω · m), ZrB ₂ (3000 ° C., 10 × 10 ⁻⁸ Ω · m), NbB ₂ (3050 ° C., 26 × 10 ⁻⁸ Ω · m), Mo ₂ B (2140 ° C., 26 × 10 ⁻⁸ Ω · m), MoB ₂ (2100 ° C., 45 × 10 ⁻⁸ Ω · m), LaB ₆ (2720 ° C., 15 × 10 ^{− 8} Ω · m), TaB ₂ (3200 ° C., 33 × 10 ⁻⁸ Ω · m), W ₂ B ₅ (2370 ° C., 22 × 10 ⁻⁸ Ω · m), CrB (2050 ° C., 45 × 10 ⁻⁸⁾ Ω · m) and CrB ₂ (2200 ° C., 30 × 10 ⁻⁸ Ω · m). Among these, TiB ₂ and ZrB ₂ having a high melting point and a small volume resistivity are preferable, and TiB ₂ is more preferable. Only one metal boride may be used, or two or more metal borides may be used.
Examples of the “metal silicide” include MoSi ₂ (1980 ° C., 22 × 10 ⁻⁸ Ω · m), TiSi ₂ (1500 ° C., 17 × 10 ⁻⁸ Ω · m) and WSi ₂ (2160 ° C., 13 × 10 ^-8 Ω · m), etc., and these are all preferable because of their low volume resistivity. Only one metal silicide may be used, or two or more metal silicides may be used.
In addition, the numerical value in the bracket | parenthesis in each metal compound is melting | fusing point and volume resistivity.

  Although the form of the metal compound in the metallized composition is not particularly limited, it is usually in a solid form and further in a powder form. That is, it is contained as a metal compound powder. The shape and dimensions of the metal compound powder are not particularly limited. The shape of the powder may be spherical, ellipsoidal, scale-like, or needle-like, or may be a mixture of powders of these shapes. Moreover, the average particle diameter of the powder (assuming that it is the average value of the maximum dimension when it is not spherical) is 1 to 10 μm, preferably 1 to 5 μm, more preferably 1 to 3 μm. When the average particle diameter is within this range, the conductor layer has excellent shape retention, and a conductor layer having a low resistance in which a molten low melting point metal is continuously formed can be obtained.

Further, when the total of the low melting point metal and the metal compound is 100% by volume, the content of the metal compound is 33 to 72% by volume, that is, the low melting point metal is 28 to 67% by volume. The metal compound content is preferably 35 to 65% by volume, that is, the low melting point metal is preferably 35 to 65% by volume, and the metal compound content is 38 to 55% by volume, that is, the low melting point metal is 45 to 65% by volume. It is more preferably 62% by volume, and the content of the metal compound is 38 to 48% by volume, that is, the low melting point metal is particularly preferably 52 to 62% by volume. When the content of the metal compound is less than 33% by volume, that is, when the low melting point metal exceeds 67% by volume, the low melting point metal in which the metal compound is melted cannot be sufficiently retained, and the predetermined shape and dimensions are reduced. It cannot be a conductor layer such as a wiring pattern. On the other hand, when the content of the metal compound exceeds 72% by volume, that is, when the low melting point metal is less than 28% by volume, the adhesion between the conductor layer and the ceramic substrate is lowered, and the conductor layer is peeled off from the ceramic substrate. Sometimes. This adhesion can be evaluated by, for example, the adhesion strength in Examples described later, and this adhesion strength is preferably 1.8 MPa or more, particularly 2.5 MPa or more, and more preferably 3.0 MPa or more.
The volume ratio of the low melting point metal to the metal compound is determined by heating a predetermined amount of the metallized composition at 500 ° C. for 10 hours in a non-oxidizing atmosphere to remove the organic binder, solvent, etc., and then the low melting point metal and other elements. On the other hand, the type of the metal compound is confirmed by X-ray diffraction, the mass of the metal compound is calculated from the quantitative value of the element, and then each mass of the low melting point metal and the metal compound is divided by the density. It can be calculated from each volume value in terms of volume.

The combination of the low-melting-point metal and the metal compound is not particularly limited, but a combination having excellent wettability is preferable. The excellent wettability is, for example, a combination in which at least a part of the low-melting-point metal is absorbed inside a molded body made of a metal compound when evaluated by the method described in the examples described later (FIG. 15). In the embodiment, FIG. 15, all of the low melting point metal is absorbed by the molded body made of the metal compound.), And the combination in which the molten low melting point metal flows on the surface of the molded body made of the metal compound (FIG. 16). Embodiment) is preferred. As a combination having excellent wettability, for example, when the main component of the low melting point metal is Cu, examples of the metal compound include WC, NbC, TaC, TiC, TiN, and TiB ₂ . Of these, WC is preferred. Further, a combination in which 95% by mass or more, particularly 100% by mass of the low melting point metal is Cu, and 95% by mass or more, particularly 100% by mass of the metal compound is WC is particularly preferable.

  In addition to the low melting point metal and the metal compound, the metallized composition may contain the following. For example, an organic vehicle can be included. This organic vehicle usually contains a binder and a solvent. The type and content of the binder and solvent are not particularly limited. When the unfired ceramic substrate and the unfired conductor layer made of the metallized composition are simultaneously fired, a material suitable for the binder, solvent, etc. contained in the unfired ceramic substrate can also be selected.

  Examples of the binder include acrylic resins, cellulose resins, polyurethane resins, polyester resins, phenol resins, and polyvinyl acetal resins. Only one type of binder may be used, or two or more types of binders may be used.

  Examples of the solvent include carbitols, cellosolves, acetic acid esters, phthalic acid esters, sebacic acid esters, monohydric alcohols, and ketones. Examples of carbitols include butyl carbitol, methyl carbitol, and ethyl carbitol. Examples of cellosolves include methyl cellosolve, ethyl cellosolve, and butyl cellosolve. Examples of acetates include methyl acetate, ethyl acetate, and butyl acetate. Examples of phthalic acid esters include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, and dioctyl phthalate. Examples of sebacic acid esters include dimethyl sebacate, diethyl sebacate, dibutyl sebacate, and dioctyl sebacate. Examples of monohydric alcohols include isopropyl alcohol. Examples of ketones include acetone, cyclohexanone, and trimethylcyclohexanone. Only 1 type may be used for a solvent and 2 or more types may be used for it.

  Although content of an organic vehicle is not specifically limited, When the metallized composition whole is 100 mass%, it can be 5-30 mass%, Preferably it can be 10-20 mass%. Moreover, among organic vehicles, a binder can be 5-30 mass%, Preferably it can be 10-20 mass%, and a solvent can be 70-95 mass%, Preferably it can be 80-90 mass%. This makes it possible to obtain a metallized composition that does not cause printing defects such as generation of mesh marks, printing sagging, blurring, and blurring, particularly when an unfired conductor layer is formed by screen printing.

  Further, in addition to the organic vehicle, the metallized composition may contain an antifoaming agent, a leveling agent, a thickener, a dispersant, a lubricant, an antioxidant, a firing shrinkage ratio adjusting agent, a ceramic component, and the like. These may be used alone or in combination of two or more.

  The viscosity of the metallized composition is not particularly limited, but using a rotating cylinder viscometer [for example, a model “VISCO TESTER VT-4” manufactured by RION, and using a No. 2 rotor (rotor diameter 15 mm, rotor thickness 1 mm) The rotor rotation speed can be measured at 62.5 rpm. ], The viscosity measured at a temperature of 23 ° C. is 5000 dPa · s or less, preferably 100 to 3000 dPa · s, more preferably 500 to 1500 dPa · s. This makes it possible to obtain a metallized composition that does not cause printing defects such as generation of mesh marks, printing sagging, blurring, and blurring, particularly when an unfired conductor layer is formed by screen printing.

  The metallized composition can be prepared by mixing a low melting point metal and a metal compound. The mixing method is not particularly limited, but a method capable of uniformly mixing the low melting point metal and the metal compound is preferable. For this mixing, it is preferable to use a mixer such as a ball mill and a bead mill. When the mixing is insufficient and the low melting point metal and the metal compound are not sufficiently uniformly dispersed, the specific resistance of the formed conductor layer tends to increase.

The method of using the metallized composition of the present invention is not particularly limited. For example, the unfired conductor layer made of the metallized composition may be directly formed on a predetermined portion of the unfired ceramic substrate or indirectly formed. May be.
This direct formation is a method in which a metallized composition is directly applied to a predetermined portion of an unfired ceramic substrate to form an unfired conductor layer. This coating method is not particularly limited, and may be any of screen printing, roll coating, curtain coating, and the like. On the other hand, to form indirectly, a metallized composition is applied to the surface of a thin film such as a polyester film to produce a metallized film, and then the unfired conductor layer is transferred from the metallized film to a predetermined portion of the unfired ceramic substrate. It is the method of forming. The coating method at this time is not particularly limited, and any of a screen printing method, a doctor blade method, a roll coating method, and a curtain coating method may be used.

  The conductor layer formed using the metallized composition of the present invention is not particularly limited. For example, a conductor layer having a minimum width of 100 μm or less, particularly 75 μm or less, and further 50 μm or less (usually 20 μm or more) can be used. Moreover, it can be set as the conductor layer whose thickness is 30 micrometers or less, especially 20 micrometers or less, and also 10 micrometers or less (usually 5 micrometers or more). Furthermore, a conductor layer having a minimum width of 100 μm or less and a thickness of 30 μm or less can be obtained, and in particular, a conductor layer having a minimum width of 75 μm or less and a thickness of 20 μm or less can be obtained. A conductor layer having a minimum width of 50 μm or less (usually 20 μm or more) and a thickness of 10 μm or less (usually 5 μm or more) can be obtained.

Further, in the metallized composition of the present invention, 33 to 72% by volume of WC was used as a metal compound, and when a conductor layer was formed by co-firing with an unfired ceramic sheet, evaluation was performed by the method in the examples described later. The specific resistance value of the conductor layer can be 3.8 to 25.0 μΩ · cm, and the adhesion strength between the conductor layer and the ceramic substrate can be 1.8 to 4.0 MPa. Furthermore, when the metal compound is 35 to 65% by volume, the specific resistance value can be 3.8 to 20.0 μΩ · cm, the adhesion strength can be 1.8 to 4.0 MPa, and the metal compound is 38 to When it is 55% by volume, the specific resistance value can be 3.8 to 12.0 μΩ · cm, the adhesion strength can be 1.8 to 4.0 MPa, and when the metal compound is 38 to 48% by volume. The specific resistance value can be 3.8 to 6.0 μΩ · cm, and the adhesion strength can be 2.5 to 4.0 MPa. Further, when the content of the metal compound is 33 to 72% by volume, even if there are voids in the conductor layer, the number of voids is small, especially there are almost no voids having a diameter of 5 μm or more, and the conductor has an excellent appearance. It can be a layer. The metal compound is in the case of TiB ₂ and TaC, same in content can be the same specific resistance and adhesion strength, respectively, it can be a conductive layer having the same excellent appearance.

[2] Ceramic wiring board The ceramic wiring board of the present invention includes a ceramic base and a conductor layer disposed on or inside the ceramic base, and the conductive layer constitutes the ceramic base by firing. A low melting point metal part made of a low melting point metal having a melting point lower than the firing temperature of the ceramic material, and a metal compound connecting part formed in the low melting point metal part and made of a metal compound having a melting point higher than the firing temperature of the ceramic material, Prepare.

  The “ceramic substrate” is a portion made of fired ceramic in the ceramic wiring board. The ceramic constituting the ceramic substrate is not particularly limited, and alumina, zirconia, cordierite, mullite, titania, quartz, forsterite, wollastonite, anorthite, enstatite, diopsite, akermanite, gehlenite, spinel, garnite, And titanates such as magnesium titanate, calcium titanate, strontium titanate and barium titanate. As this ceramic, alumina, zirconia, cordierite, mullite and the like are preferable from the viewpoints of insulation and strength. Only one type of ceramic may be used. For example, two or more types of ceramics may be used as long as they can be mixed and fired, such as alumina and zirconia.

Further, the ceramic substrate can contain components derived from the sintering aid, glass components, and the like.
The component derived from the sintering aid may be a crystalline component or an amorphous component. Examples of the component derived from the sintering aid include metal oxides such as SiO ₂ , MgO, SrO, and rare earth oxides. Further, examples of the glass component include those containing Si, Al, Na, K, Mg, Ca, Ba, B, Pb, Zn, Zr, Fe, Ti, and the like. Examples thereof include aluminosilicate glass and aluminoborosilicate glass.

The “conductor layer” is disposed on the surface or inside of the ceramic substrate. The form of the conductor layer is not particularly limited, and only one layer may be disposed on the surface or inside of the ceramic substrate, or two or more layers may be disposed on the surface or inside of the ceramic substrate. When two or more conductor layers are arranged via a part of the ceramic substrate, each conductor layer may be electrically connected by interlayer connection, and each conductor layer is independent without being connected. It may be. Furthermore, in the ceramic wiring board of the present invention, a conductor layer having a predetermined shape and size can be obtained even when a conductor layer is provided on the surface of the ceramic substrate. The conductivity of the conductor layer is not particularly limited, but the conductivity varies depending on the type of the metal compound, and therefore it is preferable to select the metal compound according to the purpose, application, and the like. The specific resistance value of the conductor layer can be 70 μΩ · cm or less, particularly 35 μΩ · cm or less at room temperature, 18 μΩ · cm or less, particularly 15 μΩ · cm or less, more preferably 10 μΩ · cm or less, and preferably 5 μΩ · cm or less. The following is more preferable. Further, the adhesion strength of the conductor layer and the ceramic substrate, as measured by the method described in Examples below, is 1.8 MPa or more, particularly 2.5 MPa or more, and more preferably 3.0 MPa or more.
Examples of the conductor layer include normal conductive wiring, resistance wiring, capacitor wiring such as a pad shape, inductance wiring, and a bonding pad.

The conductor layer includes a low melting point metal part and a metal compound connecting part formed in the low melting point metal part.
The “low-melting-point metal part” is made of a low-melting-point metal having a melting point lower than the firing temperature of the ceramic material that constitutes the ceramic substrate by firing. This low melting point metal part is a part contributing to conductivity in the conductive layer. In addition, about the low melting metal, the description regarding the low melting metal in the said metallization composition can be applied as it is. However, although the form of the low melting point metal in the metallized composition is usually a powder or the like, the form in the low melting point metal part is usually a continuous phase composed of a low melting point metal.

  The “metal compound connecting part” is formed in the low melting point metal part and mainly contains at least one of metal carbide, metal nitride, metal boride and metal silicide, and has a melting point higher than the firing temperature of the ceramic material. It is a portion made of a high metal compound. In addition, about each of a metal carbide, a metal nitride, a metal boride, and a metal silicide, the description regarding the metal compound in the said metallization composition is applicable as it is. However, the form of the metal compound in the metallized composition is usually a powder or the like, but the form in the low melting point metal part is usually a continuous phase composed of the metal compound. Further, the continuous phase may be continuous by sintering metal compound particles or the like, or may not be sintered and may be continuously in contact with adjacent particles. When the unfired ceramic substrate and the unfired conductor layer are simultaneously fired by the metal compound connecting portion, the flow of the molten low melting point metal is suppressed, and a conductor layer having a predetermined shape and size is formed.

Another ceramic wiring board of the present invention includes a ceramic substrate and a conductor layer disposed on or inside the ceramic substrate, the conductor layer containing a low-melting point metal and a metal compound. When the total is 100% by volume, the content of the metal compound is 33 to 72% by volume.
For this ceramic substrate, the description relating to the ceramic substrate in the ceramic wiring board of the present invention can be applied as it is. Moreover, about the form of a conductor layer, electroconductivity, and the adhesive strength with a ceramic base | substrate, the description regarding the conductor layer in the ceramic wiring board of the said this invention is applicable as it is. Furthermore, regarding the contents of the low melting point metal, the metal compound, and the metal compound, the description regarding the metallized composition of the present invention can be applied as it is.
The volume ratio between the low melting point metal and the metal compound is a ratio between the area of the low melting point metal and the area of the metal compound in a field of a predetermined area when the cross section of the conductor layer is observed with an electron microscope.

  In a ceramic wiring substrate, warpage may occur due to a difference in thermal expansion coefficient between the unfired ceramic substrate and the unfired conductor layer during firing. The presence or absence of warpage and the degree of warpage vary depending on the types of low melting point metal and metal compound and their ratio, the type of ceramic constituting the ceramic substrate, the firing temperature, and the like. Therefore, when setting a combination of a low-melting-point metal, a metal compound and a ceramic, a firing temperature, and the like, it is preferable to set a preferable combination and a firing temperature that can suppress this warp. The warp is the difference between the maximum height and the minimum height from the flat surface when the ceramic wiring board is placed on the flat surface. Usually, there is no problem if the difference is 300 μm or less.

  The ceramic wiring board of the present invention and the other ceramic wiring board of the present invention are a normal wiring board such as a mother board, a flip chip wiring board, a CSP wiring board, an MCP wiring board, a wiring board for a crystal, etc. As a wiring board for antenna switch modules, a wiring board for mixer modules, a wiring board for modules such as a wiring board for PLL modules and a wiring board for MCM, a wiring board for PA, a wiring board for SAW filter, etc. Can be used.

Moreover, in the wiring board of the present invention and the other ceramic wiring board of the present invention, by using the metallized composition of the present invention containing a specific amount of WC as a metal compound, the same specific resistance value and adhesion strength as described above can be obtained. It can be set as the conductor layer which has and has the outstanding external appearance similarly. The metal compound is in the case of TiB ₂ and TaC, same in content can be the same specific resistance and adhesion strength, respectively, it can be a conductive layer having the same excellent appearance.

[3] Manufacture of Ceramic Wiring Board The manufacturing method of the ceramic wiring board of the present invention and another ceramic wiring board of the present invention is not particularly limited, but can be manufactured as follows, for example.
(1) Production of unsintered ceramic sheet A ceramic raw material, a sintering aid, a binder resin, a solvent, and the like are mixed by a mixer such as a ball mill or a bead mill to prepare a slurry. The order in which each component is blended is not particularly limited, and all the components may be put into a ball mill or the like and mixed together, or may be blended and mixed according to a specific order. As the ceramic raw material, a ceramic raw material that constitutes the ceramic base can be used.

Various types of sintering aids can be used depending on the type of ceramic constituting the ceramic substrate. Examples of the sintering aid include SiO ₂ , MgO, SrO and rare earth oxides, and compounds such as carbonates and hydroxides that become these oxides upon heating. As the binder resin, acrylic resin, polyamide, polypeptide, polyvinyl butyral resin, phenoxy resin, cellulose derivative, polyoxyethylene, polyvinyl alcohol, and the like can be used. As the solvent, aromatic hydrocarbons such as toluene, aliphatic hydrocarbons such as cyclohexane, ketones such as acetone and methyl ethyl ketone, and the like can be used. These sintering aids, binder resins and solvents may be used alone or in combination of two or more. If necessary, at least one of a plasticizer, a dispersant, an antifoaming agent, a coloring agent, an oxidizing agent, and the like can be blended in the slurry.

  A sheet is formed using this slurry. This sheet can be formed on the surface of a support such as a resin film made of polyester such as polyethylene terephthalate and a metal plate made of stainless steel by a doctor blade method, a roll coater method or the like. Thereafter, the sheet is dried at a predetermined temperature depending on the type of the solvent, and the solvent is removed to produce an unfired ceramic sheet. (When only one sheet is used, the sintered body of this sheet is When two or more sheets are used, a sintered body obtained by integrally firing these sheets is a ceramic substrate.)

(2) Formation of unsintered conductor layer On the surface of the unsintered ceramic sheet prepared in (1) above, a coating film made of a metallized composition is disposed by screen printing or the like and dried to form an unsintered conductor layer. An unfired ceramic wiring board can be formed. Furthermore, when two or more conductor layers are formed on both sides of the ceramic layer in the ceramic wiring board and they are conducted, a via filling paste is filled in via holes provided at predetermined positions of the unfired ceramic sheet. By forming an unsintered conductor layer on both sides of the unsintered ceramic sheet, an unsintered ceramic wiring board can be produced.

  In the case of a multilayer wiring board, a via filling paste is filled in a via hole provided at a predetermined position of the unfired ceramic sheet, and a via hole is formed in the via hole on the surface of the unfired ceramic sheet on which the unfired conductor layer is formed. Laminate other unfired ceramic sheets filled with filling paste, form unfired conductor layers on the surface of the unfired ceramic sheets in the same way, and repeat this operation to produce unfired multilayer wiring boards (When using a plurality of sheets as described above, a sintered body of a laminate in which these sheets are laminated becomes a ceramic substrate as described above.) As the via filling paste, those having the same composition as the metallized composition and those having different compositions can be used, and those having the same composition are often used. In this way, an unfired ceramic wiring board and an unfired multilayer wiring board can be produced.

(3) Firing A ceramic wiring substrate, for example, a multilayer wiring substrate as shown in FIG. 1, can be produced by firing the unfired ceramic wiring substrate and the unfired multilayer wiring substrate prepared in (2) above. The firing temperature and the time for maintaining this firing temperature are not particularly limited, and can be set according to the types of low melting point metal and ceramic raw material. Also, the firing atmosphere is not particularly limited, and may be a non-oxidizing atmosphere such as a nitrogen atmosphere and an inert gas atmosphere such as argon, or an oxidizing atmosphere such as an air atmosphere, depending on the type of low melting point metal and ceramic raw material. it can. This non-oxidizing atmosphere is an atmosphere having a low oxygen partial pressure, and is usually an atmosphere having an oxygen partial pressure of 10 Pa or less, particularly 0.1 Pa or less (usually 0.0001 Pa or more). Further, the firing atmosphere may be a humid atmosphere. This wet atmosphere is an atmosphere in which the dew point is controlled, and is an atmosphere in which the dew point is maintained at 90 ° C. or lower, particularly 80 ° C. or lower (usually 5 ° C. or higher). Note that this firing atmosphere needs to be a non-oxidizing atmosphere when Cu is contained in the low melting point metal, and is preferably a non-oxidizing atmosphere and a wet atmosphere.

[4] When the ceramic constituting the ceramic substrate is alumina, the low melting point metal is Cu, and the metal compound is WC, the unfired ceramic substrate mainly composed of alumina, the low melting point metal mainly composed of Cu, and WC In the case of co-firing with an unfired conductor layer made of a metal compound containing as a main component, considering the shape retention of the conductor layer after firing and diffusion of molten Cu into the ceramic substrate, the firing temperature is 1200 to 1300 ° C. It is preferable that Furthermore, it is preferable that alumina is sufficiently densified when fired in this temperature range, and the relative density is 95% or more, particularly 97% or more.

Thus, in order to sufficiently densify alumina at a low temperature, it is preferable to use a fine powder having an average particle size of 0.1 to 1.0 μm, particularly 0.1 to 5 μm, as an alumina raw material. Moreover, it is preferable to use at least 4 or more types of compounds of each element of periodic table 2 group, such as Si, Mn, Ti, Zr and Mg, Ca, Sr, and Ba, as a sintering aid. Furthermore, when the total of the alumina raw material and the sintering aid is 100% by mass, the sintering aid is preferably 5 to 20% by mass in terms of oxide. Thereby, a sintered compact can be densified at the calcination temperature 1200-1300 degreeC. Incidentally, the terms of oxide, Si is _SiO 2, Mn is _MnO 2, Ti is _TiO 2, Zr is _ZrO 2, Mg is MgO, Ca is CaO, Sr is SrO, Ba is calculated as BaO.

  As a sintering aid, it is possible to use a combination of one or more of the compounds of each element of Si, Mn, Ti and Zr and one or more of the compounds of each element of Group 2 of the periodic table. preferable. Furthermore, it is preferable to use two or more compounds of each element of Group 2 of the Periodic Table. Sinterability is further improved by using two or more compounds of Group 2 elements of the periodic table. As the combination of the sintering aids, a combination of each compound of Si, Mn, Ti and Mg and a combination of each compound of Si, Mn, Ti and Ba are preferable, and each of Si, Mn, Ti, Zr and Ba is preferable. The combination of these compounds is more preferable, and the combination of each compound of Si, Mn, Ti, Zr, Sr and Ba, and the combination of each compound of Si, Mn, Ti, Zr, Mg and Ba is particularly preferable.

  As the sintering aid, oxides of the respective elements described above or compounds that are heated to become oxides can be used. Moreover, this oxide or the compound which becomes an oxide by being heated may have only one kind of the above elements, or may have two or more kinds. For example, a double oxide containing two or more elements may be used. Furthermore, the kind of the compound that is heated to become an oxide is not particularly limited, and examples thereof include carbonates, hydroxides, hydrogen carbonates, nitrates, and organometallic compounds.

  When the low melting point metal is mainly composed of Cu, the firing is performed in a non-oxidizing atmosphere having an oxygen partial pressure of 10 Pa or less, preferably 0.1 Pa or less (usually 0.0001 Pa or more). Examples of the non-oxidizing atmosphere include a nitrogen gas atmosphere and an inert gas atmosphere such as argon. Furthermore, when the low melting point metal is mainly composed of Cu, the firing atmosphere is preferably a non-oxidizing atmosphere and a humid atmosphere. This wet atmosphere is an atmosphere in which the dew point is controlled, and is usually an atmosphere in which the dew point is maintained at 90 ° C. or lower, preferably 80 ° C. or lower. In the case of Cu, the dew point is particularly preferably 7 to 35 ° C, more preferably 10 to 35 ° C, and particularly preferably 15 to 35 ° C. When the dew point is 7 to 35 ° C., the wettability between the molten Cu and the unfired alumina is high, the molten Cu is sufficiently held by the WC, and the diffusion of Cu is suppressed, so that the conductor layer has a low resistance. be able to.

Hereinafter, the present invention will be described specifically by way of examples.
[1] Manufacture of ceramic wiring board and production of conductor layer for measurement of adhesion strength (1) Preparation of metallized composition Cu powder (average particle size 3.6 μm) and WC powder (average particle size 1.5 μm) (experimental example) 2-11), TiB ₂ powder (average particle size 1.5 μm) (experimental example 12), TaC powder (average particle size 1.2 μm) (experimental example 13), ZrC powder (average particle size 1.5 μm) (experimental) Example 14) and TiC powder (average particle size 1.2 μm) (Experimental Example 15) were weighed so as to have the volume ratio shown in Table 1 and put into a ball mill provided with a resin lining. Also, this ball mill is made of alumina cobblestone, and 55 parts by weight of acetone and 15 parts by weight of butyl carbitol as a solvent [the content of this solvent is Cu powder, WC powder, TiB ₂ powder, TaC powder, ZrC powder. Or it is the value which made the sum total with TiC powder 100 mass parts. ], Mixed for 18 hours, and pulverized. Thereafter, an organic vehicle in which 4 parts by mass of ethyl cellulose as an organic binder and 12 parts by mass of acetone and 10 parts by mass of butyl carbitol as a solvent are mixed in a ball mill is 15 parts by mass when the total metallized composition is 100 parts by mass. The mixture was further mixed for 20 hours and pulverized to prepare a metallized composition.
In Experimental Example 1, a metallized composition was prepared in the same manner as in Experimental Examples 2 to 15 except that W powder was used as the metal powder for the conductor layer and no metal compound powder was used.

(2) Production of Unsintered Alumina Sheet In Experimental Examples 2 to 15, Al ₂ O ₃ powder (purity 99%, average particle size 0.6 μm) 92% by mass as the ceramic raw material powder, and SiO ₂ as the sintering aid powder Powder (purity 99%, average particle size 1.5 μm) 2.7% by mass, MgCO ₃ powder (purity 99%, average particle size 6.0 μm) 0.6% by mass, BaCO ₃ powder (purity 99%, average particle size) Diameter 1.8 μm) 1.1% by mass, TiO ₂ powder (purity 99%, average particle size 1.0 μm) 1.5% by mass, MnO ₂ powder (purity 90%, average particle size 7.0 μm) 1.5 % By mass and ZrO ₂ powder (purity 99%, average particle size 1.5 μm) 0.6% by mass [The blending amount of the following other components is the value when the total of each ceramic powder is 100 parts by mass. is there. ], 2.0 parts by mass of sorbitan monooleate as a dispersant and 20 parts by mass of methyl ethyl ketone and 15 parts by mass of toluene as a solvent were placed in a ball mill and wet mixed for 16 hours. Thereafter, 12 parts by mass of polyvinyl butyral resin as an organic binder, 4 parts by mass of dioctyl phthalate as a plasticizer, 20 parts by mass of methyl ethyl ketone and 15 parts by mass of toluene as a solvent were further mixed for 16 hours to prepare a slurry. Next, a sheet is formed by using this slurry by a doctor blade method, and this sheet is dried at 40 ° C. for 30 minutes and further at 70 ° C. for 1 hour to obtain unfired alumina having a length of 140 mm, a width of 170 mm, and a thickness of 0.1 mm. A sheet was produced.
In Experimental Example 1, 93.3% by mass of Al ₂ O ₃ powder (purity 99%, average particle size 1.2 μm) as the ceramic raw material powder, and SiO ₂ powder (purity 99%, average) as the sintering aid powder (Particle diameter 1.5 μm) 5.2 mass%, MgCO ₃ powder (purity 99%, average particle diameter 6.0 μm) 0.6 mass% and CaCO ₃ powder (purity 99%, average particle diameter 1.5 μm) An unsintered alumina sheet was produced in the same manner as in Experimental Examples 2 to 15 except that 9% by mass was used.

(3) Formation of unsintered conductor layer The metallized compositions of Experimental Examples 1 to 15 prepared in (1) above are screen-printed on the surface of the unsintered alumina sheet prepared in (2) above, and an unsintered wiring pattern Formed. Moreover, the metallized compositions of Experimental Examples 2 to 15 were screen-printed on the surface of an unfired alumina sheet to form an unfired conductor layer having a length of 2 mm, a width of 2 mm, and a thickness of 10 μm for measuring adhesion strength.

(4) Firing An unfired wiring layer and an unfired conductor layer for measuring adhesion strength produced in (3) above were formed (in Experimental Example 1, the unfired conductor layer for measuring adhesion strength was Not formed.) An unsintered alumina sheet is housed in a hydrogen furnace, and in an inert atmosphere composed of 50% by volume hydrogen gas and 50% by volume nitrogen gas, in Experimental Examples 2 to 15, 1250 ° C. No. 1 was fired at a firing temperature of 1550 ° C. and each dew point shown in Table 1 for 2 hours. Thus, in Experimental Examples 2 to 15, a conductor layer having a ceramic base made of alumina, a low melting point metal part made of Cu, and a metal compound connecting part made of WC, TiB ₂ , TaC, ZrC, or TiC, And a conductor layer for measuring adhesion strength was formed at the same time. In Experimental Example 1, a ceramic wiring substrate including a ceramic substrate made of alumina and a conductor layer made of W was manufactured.

  FIG. 2 shows a cross section of the wiring board of Experimental Example 4 observed with a scanning electron microscope at a magnification of 1500 times. According to FIG. 2, the conductor layer is in close contact with the ceramic substrate made of alumina (the black portion on the right side in FIG. 2), and the conductor layer is made of a continuous phase formed by solidified molten Cu and WC particles. It can be seen that it is formed by a continuous phase (the particles are connected to each other is a continuous phase composed of WC particles). The conductor layer 12 has a planar shape as shown in FIG. 3, has a line width of 200 μm, an inter-wiring distance of 600 μm, a thickness of 20 μm, a of 12 mm, and b of 3 mm. Reference numeral 121 denotes a resistance measurement terminal.

[2] Evaluation of conductor layer (1) Specific resistance value The resistance of the formed conductor layer was measured by a four-terminal method, and the specific resistance value was calculated using the following equation. The results are also shown in Table 1, and are shown graphically in FIG.
Specific resistance value (μΩ · cm) = [resistance value (Ω) × conductor layer thickness (μm) × conductor layer width (μm)] / [100 × conductor layer length (cm)]

(2) Adhesion Strength As shown in FIG. 4, Ni plating layer 22 is formed on the entire surface of conductor layer 21 for measuring adhesion strength by electroless plating to form a Ni plating layer 22 having a diameter of 0.5 mm. The Ni-based lead wire 23 was soldered. Thereafter, the lead wire was pulled in the vertical direction at a speed of 20 mm / min, and the strength when peeled was measured. This peel strength is defined as the adhesion strength of the conductor layer to the alumina substrate. c is 15 mm. The results are also shown in Table 1, and are shown graphically in FIG. Furthermore, the correlation between the dew point and the adhesion strength when the low melting point metal is 60% by volume is shown in the graph of FIG.

(3) Appearance The appearance of the conductor layer was observed with an optical microscope at a magnification of 450 times. Appearance evaluation criteria are as follows. The results are also shown in Table 1. 5 to 11 are explanatory diagrams based on the result of observing and photographing the conductor layer of each wiring board in Experimental Examples 2 to 8. FIG.
◯: When there are voids in the conductor layer (in the explanatory diagrams of the conductor layers in FIGS. 5 to 11, there is no conductor and the ceramic base looks black), the number of voids is small, and the diameter is particularly 5 μm or more. There are almost no voids.
X: There are many voids including voids having a diameter of 5 μm or more in the conductor layer.

  According to Table 1 and FIGS. 12 to 14, the outer appearance was good in Experimental Example 1 in which W was used as the conductor layer and was fired at 1550 ° C., which is the firing temperature of normal alumina, as in the past. It can be seen that the specific resistance is as high as 20.0 μΩ · cm. Further, in Experimental Example 2 in which the content of WC is as low as 30% by volume, although the specific resistance value is as low as 7.0 μΩ · cm, there are many voids in the conductor layer, and the shape retention of the conductor layer is poor. Furthermore, in Experimental Example 9 in which the content of WC is excessively 75% by volume, the appearance is good, but the adhesion strength is as low as 1.2 MPa, and the adhesion between the conductor layer and the ceramic substrate is inferior.

On the other hand, in Experimental Examples 3 to 8 and 10 to 11 in which the metallized composition contains 35 to 70% by volume of WC, the specific resistance value is 24.4 μΩ · cm or less, the appearance is excellent, and the adhesion strength is sufficient. You can see that it ’s big. Moreover, in Experimental Examples 3-5, 10, and 11 in which the content of WC is 35 to 45% by volume, the specific resistance value is 4.0 to 5.0 μΩ · cm, which is particularly low resistance. Furthermore, it is found that the adhesion strength is particularly high in Experimental Examples 3 to 4 and 11 in which the content of WC is 35 to 40% by volume and the dew point is 20 to 30 ° C. In Experimental Example 12 containing 40% by volume of TiB ₂ , the specific resistance value is sufficiently low as 3.7 μΩ · cm, and in Experimental Example 13 containing 40% by volume of TaC, the specific resistance value is 5.8 μΩ. It can be seen that it is as low as cm and the adhesion strength is sufficiently large. Further, in Experimental Example 14 containing 40% by volume of ZrC, the specific resistance value was 31.6 μΩ · cm, and in Experimental Example 15 containing 40% by volume of TiC, the specific resistance value was 66.8 μΩ · cm. Higher than 1. As described above, a conductor layer having a high specific resistance value can be obtained depending on the type of the metal compound even if it has excellent shape retention and appearance. Therefore, it is preferable to select the metal compound depending on the purpose and application.
5 to 11, in Experimental Example 2 (see FIG. 5) in which the WC content is 30% by volume, the specific resistance value is not so high because the WC is small, but the diameter of the conductor layer exceeds 5 μm. Many large voids are observed, many small-diameter voids, and the appearance is poor. Further, in Experimental Example 3 (see FIG. 6) in which the WC content is 35% by volume, a slightly large void is observed in the conductor layer, but the specific resistance value is sufficiently low. Furthermore, in Experimental Examples 4 to 8 (see FIGS. 7 to 11) containing 40 to 60% by volume of WC, although fine voids are seen, the appearance is good. In Experimental Examples 4 to 8, it can be seen that the specific resistance value increases as WC increases.

[3] Evaluation of wettability between low melting point metal and metal compound The wettability was evaluated as follows.
(1) Cu powder (average particle size 3.6 μm), which is a powder of a low melting point metal, is press-molded to form a disk-shaped molded body having a diameter of 10 mm and a thickness of 1 mm, and this molded body is then subjected to a pressure of 98 MPa. CIP processed.
(2) WC powder (average particle size 1.5 μm), TaC powder (average particle size 1.2 μm), NbC powder (average particle size 1.5 μm), TiC powder (average particle size 1.2 μm), TiN powder ( Each of an average particle diameter of 1.2 μm) and TiB ₂ powder (average particle diameter of 1.5 μm) was press-molded to form a disk-shaped molded body having a diameter of 19 mm and a thickness of 7 mm, and then subjected to CIP treatment at a pressure of 686 MPa. .
(3) On the molded body made of the metal compound produced in the above (2), the molded body made of Cu produced in the above (1) is placed in the same center and accommodated in a hydrogen furnace. The atmosphere is a dry mixed gas atmosphere of 50% by volume of nitrogen and 50% by volume of hydrogen, then the temperature is raised to 1250 ° C. at a rate of temperature increase of 6 ° C./min, held at 1250 ° C. for 15 minutes, and then released to room temperature. It was cooled and removed.
(4) In each taken-out test body, it was observed visually whether the form of the molded body made of Cu (low melting point metal) was one of the following FIGS.

  FIG. 15 schematically shows a particularly preferable state in which all of the low-melting point metal has penetrated into a molded body made of a metal compound. FIG. 16 shows the case where a part of the low melting point metal penetrates into the molded body made of the metal compound or does not penetrate, but the low melting point metal flows on the surface of the molded body (solidifies during observation). ) And the like. Further, FIG. 17 schematically shows a state where the low melting point metal is spherical and the wettability between the low melting point metal and the molded body made of the metal compound is inferior. In addition, the wettability of the low melting point metal and the molded body made of the metal compound is inferior, and the low melting point metal may flow down from the surface of the molded body when melted.

As a result of evaluating the wettability between Cu, which is a low melting point metal, and each metal compound as described above, the WC was in the state of FIG. 15 and was particularly excellent in wettability with Cu. Further, NbC, TaC, TiC, TiN, and TiB ₂ were in the state of FIG. 16 and were excellent in wettability with Cu. In the same manner as in (2) above, a disk-shaped formed body using alumina, which is an oxide of aluminum, and CIP-treated, the state shown in FIG. 17 is obtained, and the metal oxide has a wettability with Cu. It turns out that it is inferior.

[4] Evaluation of warpage (1) Preparation of test specimen for warpage evaluation 60% by volume of Cu powder (average particle size 3.6 μm), WC powder (average particle size 1.5 μm), TaC powder (average particle size 1. 2 μm), NbC powder (average particle size 1.5 μm), TiC powder (average particle size 1.2 μm), TiN powder (average particle size 1.2 μm) and TiB ₂ powder (average particle size 1.5 μm). The metallized composition was prepared in the same manner as in the above [1] and (1). Further, each metallized composition was screen-printed in the same manner as in the above [1] and (3) on the surface of an unfired alumina sheet produced in the same manner as in the above [1] and (2), An unfired conductor layer having a width of 50 mm and a thickness of 0.1 μm was formed. Thereafter, in the same manner as in the above [1] and (4), a test specimen for warpage evaluation was produced by simultaneous firing at 1250 ° C. and a dew point of 20 ° C.

(2) Evaluation of Warpage Warpage of each test specimen for warpage evaluation produced in the above (1) was evaluated by the difference between the maximum height and the minimum height from the flat surface when the test body was placed on the flat surface. As a result, in WC, the difference between the maximum height and the minimum height is 20 μm, and it can be said that there is substantially no warpage. Moreover, warping is the difference in TiC and TiB ₂ is 50~100μm is small, NbC, the difference in the TaC and TiN are warpage is 200~300μm was large. Thus, it can be seen that the combination of Cu and WC is a preferable combination from the viewpoint of warpage in co-firing with an unfired alumina substrate as well as excellent wettability.

[5] Mixing of low melting point metal and metal compound and examination of grinding method Conductor when Cu powder and WC powder are mixed by ball mill and pulverized, and mixed and pulverized using mortar and pestle The external appearance of the layer was observed, its resistance was measured, and the specific resistance value was calculated in the same manner as described above.
(1) Preparation of metallized composition 60% by volume of Cu powder (average particle size 3.6 μm), 40% by volume of WC powder (average particle size 1.5 μm) (total mass is 100 g), 50 ml of acetone and butylcarb as solvent 20 ml of torr was mixed (1) for 16 hours using a cobblestone made of alumina by a ball mill with a resin lining, and pulverized. (2) A dispersion having the same composition was mixed and ground for 15 minutes using a mortar and pestle. Thereafter, in both cases (1) and (2), 25 ml of acetone and 14 ml of butyl carbitol as the solvent and 3.8 g of ethyl cellulose as the organic binder were further added. In (1), 18 hours, in (2) Mixing and pulverization were continued for 5 minutes, respectively, and then bathing was performed to prepare a metallized composition.

(2) Formation and firing of unfired conductor layer Each metallized composition prepared in (1) above was screen-printed on the surface of an unfired alumina sheet prepared in the same manner as in [1] and (2) above. Then, an unfired conductor layer having the same planar shape and thickness as those in [1] and (3) is formed, and then the unfired ceramic wiring board is subjected to a vacuum high-temperature furnace (oxygen partial pressure is 0.1 Pa or less). The ceramic wiring board was manufactured by holding at 1250 ° C. for 2 hours and firing.

(3) Evaluation of Conductor Layer The specific resistance value of the formed conductor layer was calculated in the same manner as [2] and (1). Further, the appearance of the conductor layer was observed and evaluated in the same manner as [2] and (2). As a result, when mixed and pulverized using a ball mill as in (1) above, both Cu and WC are uniformly dispersed as fine particles as shown in FIG. A continuous phase was formed, and the specific resistance value was 4 μΩ · cm. On the other hand, when mixed and pulverized using a mortar and pestle as in (2) above, Cu does not sufficiently form a continuous phase as shown in FIG. 19, and the specific resistance value is 6 μΩ · cm. Met. Thus, in order to affect the appearance and resistance of the conductor layer formed by the mixing and pulverization method, the low melting point metal and the metal compound can be mixed and pulverized by a ball mill or the like, and dispersed sufficiently uniformly with each other. preferable.

  In the present invention, the present invention is not limited to the specific embodiments described above, and various modifications can be made within the scope of the present invention depending on the purpose, application, and the like. That is, the warpage of the ceramic wiring board varies depending on the ceramic material, the low melting point metal and the metal compound, the combination thereof, the firing temperature, and the like that constitute the ceramic portion. Even in each case, in each of NbC, TaC, and TiN, in which the warpage was large in the above evaluation results, for example, by setting the firing temperature to an appropriate temperature lower than 1250 ° C., the warpage can be further suppressed.

It is a schematic diagram which shows the cross section of an example of the ceramic wiring board (multilayer wiring board) of this invention. It is explanatory drawing based on the result which observed the cross section of the ceramic wiring board of Experimental example 4 with the scanning electron microscope, and image | photographed. It is a schematic diagram which shows the planar shape of the conductor layer in the ceramic wiring board of each experiment example. It is a schematic diagram which shows the mode of the test body for measuring adhesive strength. It is explanatory drawing based on the result of having observed and image | photographed a part of conductor layer formed in the ceramic wiring board of Experimental example 2 with the optical microscope. It is explanatory drawing based on the result of having observed and image | photographed a part of conductor layer formed in the ceramic wiring board of Experimental example 3 with the optical microscope. It is explanatory drawing based on the result of having observed and image | photographed a part of conductor layer formed in the ceramic wiring board of Experimental example 4 with the optical microscope. It is explanatory drawing based on the result of having observed and image | photographed a part of conductor layer formed in the ceramic wiring board of Experimental example 5 with the optical microscope. It is explanatory drawing based on the result of having observed and image | photographed a part of conductor layer formed in the ceramic wiring board of Experimental example 6 with the optical microscope. It is explanatory drawing based on the result of having observed and image | photographed a part of conductor layer formed in the ceramic wiring board of Experimental example 7 with the optical microscope. It is explanatory drawing based on the result of having observed and image | photographed a part of conductor layer formed in the ceramic wiring board of Experimental example 8 with the optical microscope. It is a graph showing the correlation with WC content and specific resistance value in the conductor layer formed in the ceramic wiring board of Experimental Examples 1-9. It is a graph showing the correlation with WC content and adhesion strength in the conductor layer formed in the ceramic wiring board of Experimental Examples 2-9. It is a graph showing the correlation with the dew point and adhesion strength in the conductor layer formed in the ceramic wiring board of Experimental example 4, 10 and 11. It is explanatory drawing which shows typically a mode when wettability is especially excellent when the wettability of Cu and various metal compounds is evaluated. It is explanatory drawing which shows typically a mode when wettability is excellent when the wettability of Cu and various metal compounds is evaluated. It is explanatory drawing which shows typically a mode when wettability is inferior, when wettability with Cu and various metal compounds is evaluated. It is explanatory drawing based on the result of having observed and photographed the external appearance of the conductor layer in a ceramic wiring board at the time of mixing and grind | pulverizing Cu and WC with a ball mill. It is explanatory drawing based on the result of having observed and image | photographed the external appearance of the conductor layer in a ceramic wiring board at the time of mixing and grind | pulverizing Cu and WC with a mortar and a pestle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Ceramic wiring board, 11; Ceramic part, 12; Conductor layer, 121; Resistance measurement terminal, 13 via conductor, 21; Adhesion strength measurement conductor layer, 22; Ni plating layer, 23; Lead wire, 31; Molded body, 32; Cu molded body, 321; Cu infiltrated into alumina molded body, 322; Melted and flowable Cu, 323;

Claims (11)

  A low melting point metal mainly composed of at least one of Cu, Ag and Au, and a metal compound mainly composed of at least one of metal carbide, metal nitride, metal boride and metal silicide. A metallized composition containing the metal compound in an amount of 33 to 72% by volume when the total of the low melting point metal and the metal compound is 100% by volume. The metallized composition according to claim 1, wherein the metal compound has a volume resistivity of 45 × 10 ⁻⁸ Ω · m or less.   The metallized composition according to claim 1 or 2, wherein the low-melting-point metal has Cu as a main component, and the metal compound has WC as a main component.   The metallized composition according to claim 3, wherein the low-melting-point metal is 18.0 to 53.5% by weight when the total of the low-melting-point metal and the metal compound is 100% by weight. In a ceramic wiring board comprising a ceramic substrate and a conductor layer disposed on or inside the ceramic substrate,
The conductor layer is formed in a low melting point metal portion made of a low melting point metal having a melting point lower than the firing temperature of the ceramic material that constitutes the ceramic base by firing, and is formed in the metal carbide, metal A metal compound connecting portion comprising at least one of a nitride, a metal boride, and a metal silicide as a main component and comprising a metal compound having a melting point higher than the firing temperature of the ceramic material. Ceramic wiring board. The metallized composition according to claim 5, wherein the volume resistivity of the metal compound is 45 × 10 ⁻⁸ Ω · m or less.   The ceramic wiring board according to claim 6, wherein the metal compound connecting portion is formed by bringing particles made of the metal compound into contact with each other.   The ceramic wiring board according to claim 6 or 7, wherein the low melting point metal is mainly composed of at least one of Cu, Ag and Au. In a ceramic wiring board comprising a ceramic substrate and a conductor layer disposed on or inside the ceramic substrate,
The conductor layer is mainly composed of a low melting point metal mainly composed of at least one of Cu, Ag and Au, and at least one of metal carbide, metal nitride, metal boride and metal silicide. And the metal compound content is 33 to 72% by volume when the total of the low melting point metal and the metal compound is 100% by volume. substrate. The metallized composition according to claim 9, wherein the volume resistivity of the metal compound is 45 × 10 ⁻⁸ Ω · m or less.   The ceramic wiring board according to claim 6, 7, 9 or 10, wherein the low melting point metal contains Cu as a main component and the metal compound contains WC as a main component.