JPH03116608A - Conductor paste and conductor - Google Patents

Abstract

PURPOSE:To sufficiently secure adhesion strength of a base and a conductor and avoid aging deterioration of the adhesion strength and reduce generation of warping by specifying the composition of a paste for forming the conductor of the base. CONSTITUTION:The composite of a conductor paste contains Ag or an Ag alloy and Pd, which are fundamental components of a conductor, and more than two kinds of metal oxides of Al, Cu, Sr, Mg and Ca and/or their precursors and further contains vehicles. As examples of the Ag alloy, an Ag-Pd alloy containing Pd by less than 25wt.%, an Ag-Pd alloy or an Ag-Pd-Pt alloy containing Pd by less than 25wt.% and Pt by less than 10wt.%, etc., may be cited. After sintering, oxides of those metals therefore exist near the interface of a conductor 2 and a base 4 and high adhesion strength is permanently obtained by anchor effect, and warping is also prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a paste for forming a conductor of a wiring board on which elements such as a semiconductor integrated circuit are mounted, and a thick film conductor obtained by firing the paste.

<Prior Art> In recent years, the development of wiring boards obtained by co-firing a board material and a conductor at a low temperature of about 1000° C. or lower has been progressing.

The substrate material for such low-temperature fired wiring boards is alumina.
The main component is a glass composite.

On the other hand, as the conductor material, instead of the conventional W or Mo, Al, which has an excellent low conduction resistance (approximately 2 mΩ/hole), and an Ag-Pd alloy, which has improved migration resistance, are used.

By the way, the conductor forming paste before firing contains carbon which reacts with the alumina of the substrate to form spinel during simultaneous firing.
Attempts have been made to add uO and the like.

However, even if such a conductor-forming paste is co-fired with a glass-alumina composite substrate, only a very small amount of spinel is produced, and therefore sufficient adhesive strength with the conductor cannot be obtained.

In particular, even if the initial strength is sufficient, aging deterioration occurs (for example, aging at 150°C for 1000 hours reduces the initial strength from 3.0 Kgf/2mm to 1.5 Kgf/2mm2 or less).
, sufficient adhesive strength cannot be obtained continuously.

Further, the warpage after firing becomes large.

<Problems to be Solved by the Invention> The purpose of the present invention is to create a conductive paste that ensures sufficient adhesive strength between a substrate and a conductor through simultaneous firing, and that the adhesive strength is resistant to deterioration due to aging (and that causes less warpage). and conductors.

<Means for Solving the Problems> Such objects are achieved by the following inventions (1) to (7).

(1) Ag or Ag alloy, Al1, Cu, Ca, S
Compounds of two or more different metal species selected from oxides of metal compounds of one or more metals r, Mg, and Ba and/or their precursor compounds (provided that two or more metals are 8β+Cu) A conductive paste characterized by containing (excluding cases).

(2) Ag, Pd, A42, Cu, and Ca.

Compounds of two or more different metal species selected from oxides of different metal compounds of one or more of Sr, Mg, and Ba and/or their precursor compounds (provided that two or more metals are Aff+Cu) A conductive paste characterized by containing () and (excluding cases).

(3) The metal species of the two or more compounds are Ag and/or
or Cu, Ca s S r % M g and Ba
The conductor paste according to (1) or (2) above, which is one or more of the following.

(4) The content of the two or more types of compounds is such that when the paste composition is fired to form a conductor, 1 oxide is present in the conductor.
The conductive paste according to any one of (1) to 3) above, which has a content of ~12 wt%.

(5) the two or more compounds contain Ag and Cu,
The oxide of Al and Cu is copper aluminate or
The conductor paste according to any one of (1) to 4) above, which is copper aluminate and alumina.

(6) A conductor formed on the surface and/or inside of a low-temperature fired ceramic substrate by co-firing, the composition of which is Ag or Ag-based alloy, Aρ, Cu, Ca, S
r, two or more metals of Mg and Ba (however, An+
A conductor characterized by containing an oxide of Cu).

(7) The content of the oxides of the two or more metals is 1 to 8w.
The conductor according to (6) above, which is t%.

Specific composition> Hereinafter, a specific configuration of the present invention will be explained in detail.

The composition of the conductor paste of the present invention includes Ag or Ag alloy or Ag and Pd, which is the basic composition of the conductor, and Al
, Cu, Sr, Mg and Ca metal oxides and/or their precursors (however, if the metal is Al
10 Cu), and further includes a vehicle.

Although the basic composition of the paste composition is Ag, it may alternatively be a binary or higher alloy of Ag and a desired metal. As an example of Ag alloy, preferably 25w
Ag-Pd alloy containing t% or less of Pd, preferably 25
Pd below wt% and PT below 10wt% if necessary
Ag-Pd alloy or Ag-Pd-Pt alloy containing
Preferred examples include Ag-Pt alloys containing 10 wt% or less of pt.

Components other than Ag in such an Ag alloy and their content are appropriately determined depending on the purpose. For example, Ag-
Pd alloy has better migration resistance and moisture resistance than pure Ag. If the Pd content of this alloy is less than 5 wt%, the above effect will be small, and if it exceeds 25 wt%, the conductivity of the conductor will deteriorate.
It is preferable to set it as wt%.

Also, Ag and other metals such as Pd may be present separately in the paste composition.

In this case, an Ag alloy is formed by subsequent firing.

Such Ag or Ag alloys, or metals that become Ag alloys, such as Pd, are usually present in the paste composition as particles.

The average particle size of Ag or Ag-based alloy particles is 0.01 to 1
It is preferable to set the number to about 0.

The reason for this is that if the average particle size is less than 0.01 μm, the shrinkage rate of the conductor becomes too large, and if it exceeds 10 μm, the printability and dispersibility of the conductor paste composition will be poor.

Further, it is preferable that the average particle diameter of the metal particles forming the Ag alloy, particularly the Pd particles, is about 0.01 to 10 ps.

The reason for this is that if the average particle size is less than 0.01pxr, the shrinkage rate will be insufficient, as in the case of the Ag or Ag alloy particles mentioned above, and if it exceeds 10μ, the improvement in migration resistance due to the addition of Pd will occur. This is because it becomes smaller.

A feature of the present invention is that the paste composition contains two or more types of oxides of predetermined metals and/or precursor compounds that become oxides upon firing.

As a result, after firing, the above metal oxide exists near the interface between the conductor and the substrate, and high adhesive strength can be permanently obtained due to the anchor effect.

In particular, Sn in the solder when an element etc. is soldered to a conductor.
Even if the adhesive diffuses into the conductor and this may reduce the adhesive strength between the substrate and the conductor, high adhesive strength can be maintained against this.

Warping is also prevented.

The metals constituting the metal oxide and/or its precursor compound used in the present invention are two or more of Aρ, Cu, Ca, Mg, Sr, and Ba. .

The effects of the present invention can be achieved by using two or more of these, ie, 2 to 6 of these in combination.

However, Afi+Cu was developed by the inventors in Japanese Patent Application No. 63-8.
Since it is proposed in No. 6396, it is excluded in this application.

In such a case, a more preferable combination is (
Afi and/or Cu) + (1 to 4 types of Ca, Sr, Mg, and Ba).

In this case, as Al1 and/or Cu, Ag or Al+Cu is preferable, and Al+Cu is particularly preferable.

Further, as the 1 to 4 types of Ca, Sr, Mg, and Ba, those having one or more of Ca, Sr, and Mg as an essential component are preferable, and in particular, the above 1 to 4 types having Ca as an essential component are preferable.
Seeds are preferred.

As Ag and Cu oxides, copper aluminate (Cu
Aff204, CuAl202) and the like. In addition, it is not limited to the one type mentioned above, but two or more types, such as copper aluminate and alumina (α-A jla 203
) Copper oxide and alumina may also be used.

In addition, when alumina or its precursor is included as an essential component in the paste composition, the consistency of the shrinkage rate when the substrate and the conductor shrink during subsequent firing is improved, and the interface between the substrate and the conductor improves. This has the advantage of suppressing the occurrence of cracks in the vicinity.

Any precursor compound for Ag and Cu oxides may be used as long as it becomes Ag and Cu oxides by firing, such as CuO and Al1 (OH).
Examples include Cu metal and Ag(OH).

In addition, in the present invention, in the case where Al1 and Cu are essential, the most preferable case is to use oxides of Ag and Cu, especially copper aluminate (CuAg204), from the viewpoint of ease of production, stability of properties, etc. More preferably, it is added as a paste. However, this does not apply to precursor compounds of Al1 and Cu oxides as long as they do not cause the above problems.

Furthermore, examples of oxides of divalent metals such as Ca, Mg, Sr and Ba include Cab and MgO.

Examples include SrO, BaO, and composite oxides thereof.

Further, as these precursors, hydroxides, carbonates, sulfates, nitrates, organic salts, etc. can also be used.

The content of two or more metal oxides and/or their precursor compounds in the paste composition is such that when the paste composition is fired to form a conductor, the content of two or more metal oxides and/or their precursor compounds is It is preferable that the content is 1 to 12 wt%.

The reason for this is that if the content of oxide in the conductor is less than 1wt%, sufficient adhesive strength cannot be permanently obtained;
This is because if it exceeds t%, the conduction resistance of the conductor increases, the conductivity deteriorates, and the solder wettability decreases.

With such a content, the addition amount ratio of two or more types of compounds is arbitrary.

However, in a more preferable case, the content of Ag and Cu is such that the amount of oxides after firing is 0.5 to 8 wt%.
, particularly preferably 2 to 8 wt%.

In this case, the content of Aj2 in the 8β and Cu is preferably 30 to 100 wt%, particularly 40 to 60 wt% of Al2, as the amount of oxide after firing.

In particular, it is preferable to add copper aluminate so that the content in the conductor is about 3 to 8 wt%, and when alumina is added, the content in the conductor is 1 to 3 wt%.
It is preferable to add so that the amount of

In a more preferable case, the content of 1 to 4 of Ca, Mg%Sr, and Ba is preferably such that the amount of oxides after firing is 0.5 to 4 wt%.

In this case, it is preferable that one or more of the oxides of Ca%Mg and Sr account for 40 to 100wt% of these, and in particular, Ca accounts for 60 to 100wt% of these.
It is preferable that it accounts for t%.

Two different types of metals among these oxides or precursors
The species, especially the copper aluminate and the divalent metal oxide or precursor, are usually present in the paste as powder or granules.

The average particle size of these powders is preferably 0.1 to 1 (about the size of scales).

The reason for this is that if the average particle size is less than 0.1, the effect of improving the consistency of the shrinkage rate between the substrate and the conductor cannot be sufficiently obtained, and if the average particle size exceeds 10, the This is because the effect of suppressing aging deterioration is insufficient.

As a vehicle for the paste composition, a binder such as Nitino 1 cellulose, Nido cellulose, or acrylic type Yoyoyo can be used.
Examples include solvents such as terpineol and butyl-bitol, fine dispersants thereof, and activators, and any one of these may be added as appropriate depending on the purpose.

In general, the proportion of the vehicle in the paste is 1.
It is about 0 to 70 wt%.

Further, the paste may contain sludge in relation to the conductor component.

Next, the conductor of the present invention will be explained.

FIG. 1 shows a multi-counterfeit circuit containing the conductor of the present invention! It is a partial cross-sectional view of a single plate.

As shown in the figure, the multilayer wiring board l has an insulating substrate 4 in which a plurality of layers are laminated and integrated by firing, and internal conductors 2 in a predetermined pattern are formed inside this substrate 4. An outer conductor 3 is formed in a portion where the inner conductor 2 is exposed on the surface of the substrate 4.

The constituent materials of the substrate 4 include alumina-borosilicate glass, alumina-lead borosilicate glass, alumina-barium borosilicate glass, and alumina-borosilicate glass, which can be fired simultaneously with the inner and outer conductors 2.3 and the resistor 8. Low temperature sintered materials containing glass and oxide aggregates such as calcium glass, alumina-strontium borosilicate glass, alumina-magnesium borosilicate glass, etc. are preferred.

In such a substrate material, the glass content C, g
J(: It is preferable to set it to about 50 to 80 wt%.

The internal conductors 2 are usually multilayered and electrically connected to each other via through holes 5 formed in the thickness direction of the substrate 4.

The external conductor 3 is formed on the surface of the substrate 4 and is used as a pad for soldering surface-mounted components 7 such as chip components such as chip inductors and chip capacitors, semiconductor integrated circuit elements, and elements such as diodes with solder 6. or used for conduction to the resistor 8.

Note that an insulating coating layer 9 is formed to cover this resistor 8.

The conductor of the present invention is applied to the inner conductor 2 and/or the outer conductor 3. That is, since both the inner conductor 2 and the outer conductor 3 are bonded to the substrate 4, it is possible to prevent cracks from occurring near the interface thereof.

Note that the outer conductor 3 is made of a conductor mainly made of Ag-Pd alloy, which has excellent migration resistance and moisture resistance, and the inner conductor 2 is made of a conductor mainly made of Ag, since good conductivity is given priority. is preferred.

Also, I! of the internal conductor 2! ! [Usually about 5 to 20,
The film thickness of the external conductor 3 is usually about 5 to 20 μs.

The conduction resistance of the inner conductor and the outer conductor depends on their composition, but for boat fishing, the former is preferably about 2 to 10 mΩ/mouth, and the latter is about 10 to 3 ohmΩ/mouth.

Next, preferred examples of the paste composition and conductor manufacturing method of the present invention will be described.

The paste composition includes metal grains such as the aforementioned AA grains or Ag-based alloy grains or AA grains and Pd grains, and AA,
It can be obtained by mixing oxides of Cu, Ca%Mg, Sr, and Ba and/or their precursor compounds with powder, adding a vehicle such as a binder and solvent, and kneading these to form a slurry. I can do it. here,
The viscosity of the paste composition is preferably adjusted to about 30,000 to 300,000 cps.

A conductor is manufactured using such a paste composition through the following steps.

# fjt, fa tan11 shi? ) *s++-s
, -s, + m ry eh, +.

This green sheet is made of aggregate such as alumina powder, which is the raw material for the substrate, and glass powder (for example, borosilicate glass).
A binder resin, a solvent, etc. are added thereto, and the mixture is kneaded to form a slurry. A predetermined number of green sheets having a thickness of about 0.1 to 0.3 mm are produced by, for example, a doctor blade method.

Next, through holes 5 are formed in the green sheets using a punching machine or a mold press, and then the paste composition is printed on each green sheet by, for example, screen printing to form internal and external conductor layers in a predetermined pattern. At the same time, the through hole 5 is filled.

In addition, resistor raw material paste (for example, Ru
O2 (containing glass frit)) is printed by a screen printing method or the like to form the resistor 8. Note that the resistor 8 is not limited to the case where it is integrally sintered with the substrate, but may be formed by printing and baking the substrate after baking the substrate.

Next, overlap each green sheet and heat press (approximately 4
0 to 120° C. and 50 to 100,100 O/cm 2 ) to form a green sheet laminate, and if necessary, the binder is removed, cutting grooves are formed, etc.

After that, the green sheet laminate was heated for 800 minutes in normal air.
The multilayer wiring board is fired and formed at a temperature of about 1000°C to obtain a multilayer wiring board in which internal and external conductors are formed on the substrate 4. Since the oxides of Al1 and Cu are contained in the conductor, an anchor effect occurs near the interface between the conductor and the substrate, so that high bonding strength between the conductor and the substrate can be permanently obtained.

Thereafter, a predetermined surface mount component 7 is soldered to the external conductor 3, and an insulating coating layer 9 is formed to obtain the multilayer wiring board 1 shown in FIG. 1.

Note that the substrate may be manufactured by a printing method instead of the green sheet method described above.

Although an example in which the present invention is applied to a multilayer wiring board has been described above, the present invention is not limited to this, but can also be applied to a single layer board such as a co-fired wiring board.

<Example> Hereinafter, specific examples of the present invention will be described.

(Example 1 of the present invention) 20 to 40 parts by weight of an acrylic resin and a high boiling point solvent (terpineol) were added as a vehicle to 100 parts by weight of the pigment of a paste composition for a conductor having the following composition, and the mixture was kneaded to form a composition for a conductor. Obtained.

Ag: 100wt% CuAflz 04: 4wt%Ca(OH)
: 2wt% (CaO conversion) In addition, Al,
CuAj2z 04 and Ca(OH) had average particle diameters of 1.0, 2, 2, and 2, respectively. It was added as a powder.

(Example 2 of the present invention) 20 to 40 parts by weight of an acrylic resin and a high boiling point solvent (terpineol) were added as a vehicle to 100 parts by weight of the pigment of a paste composition for a conductor having the following composition, and the mixture was kneaded to form a composition for a conductor. Obtained.

Ag: 85wt% Pd: 15wt% AAxOs: 1wt% Ca(OH): 4wt% (CaO conversion) In addition, Ag, Pd%A j2203 and Ca(
OH) have average particle diameters of 1.0, 1, Op, and 1, respectively.
．． It was added as a powder of 5 and 2.0 μm.

(Example 3 of the present invention) 20 to 40 parts by weight of an acrylic resin and a high boiling point solvent (terpineol) were added as a vehicle to 100 parts by weight of the pigment of a paste composition for a conductor having the following composition, and the mixture was kneaded to form a composition for a conductor. Obtained.

Ag: 85wt%Pd
:15wt%CuA ρz 04 :
4wt%Ca(OH): 2wt% (
CaO conversion) In addition, A g P d %Cu A A
20 g and Ca(OH) had an average particle size of 1.0μ and 1.0μ, respectively. Own, 2.0ta and 260μ
It was added as a powder.

(Example 4 of the present invention) 20 to 40 parts by weight of an acrylic resin and a high boiling point solvent (terpineol) were added as a vehicle to 100 parts by weight of the pigment of a paste composition for a conductor having the following composition, and kneaded to obtain Example 2 of the present invention. A conductor composition was similarly obtained.

Ag-Pd alloy (Pd15wt%): 100wt% CuAl1x O4: 4wt% Ca(OH): 2wt% (CaO conversion)
Note that the Ag-Pd alloy is Ag-P with an average particle size of 1.0 mm.
The above powder was used except that it was added as alloy grains.

(Example 5 of the present invention) 20 to 40 parts by weight of an acrylic resin and a high boiling point solvent (terpineol) were added as a vehicle to 100 parts by weight of the pigment of a paste composition for a conductor having the following composition, and the mixture was kneaded to form a composition for a conductor. Obtained.

Ag: 85wt% Pd: 15wt% CuAAz 04: 4wt% Ca(OH): 2wt% (CaO conversion) Sr
(OH)z・8Ha O: 1wt% (SrO conversion)
was added as Pd particles with an average particle size of 1.0 mm, and Cu A
j2*04 is the average particle size 2. As Opm powder,
Ca(OH), 5r(OH), and .8H20 were added as powders with an average particle size of 2.0μ.

(Example 6 of the present invention) 20 to 40 parts by weight of an acrylic resin and a high boiling point solvent (terpineol) are added as a vehicle to 100 parts by weight of the pigment of a paste composition for conductors having the following composition, and the mixture is kneaded to form a composition for conductors. I got it.

Ag: 85wt%Pd
:15wt%CuO1 mole and A! ! , (OH): 4 wt% Mixing ratio with 2 moles Ca(OH): 1 wt% (in terms of CaO) Mg
(OH)2: 1wt% (M g O conversion) Note that Ag is Ag grains with an average grain size of 1.0, and Pd is
Added as Pd particles with an average particle size of 1.0μ, CuO1Al
(OH) Ca(OH) and Mg(OH) were each added as powders with an average particle size of 2.0-.

(Example 7 of the present invention) 20 to 40 M parts of an acrylic resin and a high boiling point solvent (≠ rubineol) are added as a vehicle to 100 parts by weight of the pigment of a paste composition for a conductor having the following composition, and the mixture is kneaded to form a composition for a conductor. I got it.

Ag: 85wt%Pd
: 15 wt% Mixing ratio of 1 mole of CuO and 2 moles of Aρ(OH) a-AIlx O3: 1 wt% (in terms of α-Al2O3) Ca(OH): 2 wt% (in terms of CaO) Mg (OH): 0.5 wt% ( Mg
(converted to O) Ba (OH)2.8H, O: 0.5wt% (BaO
(conversion) In addition, Ag is added as Ag particles with an average particle size of 1.0: 2 wt%, Pd is added as Pd particles with an average particle size of 1.0, Cub, Aj2 (OH) Ca (OH) M
g (OH) and Ba(OH) 8H20 respectively as powders with an average particle size of 2.0-
No. 3 was added as a powder with an average particle size of 1.5.

(Comparative Example 1) 20 to 40 parts by weight of an acrylic resin and a high boiling point solvent (terpineol) were added as a vehicle to 100 parts by weight of the pigment of a conductor paste composition having the following composition, and the mixture was kneaded to obtain a conductor composition. Ta.

Ag: 85 wt% Pd: 15 wt% In addition, Ag is Pd as Ag grains with an average grain size of 1.0
is an average particle size of 1. It was added as Q- Pd grains.

Comparative Example 2 In Comparative Example 1 above, the average particle size of Pd was set to 0.15-, and A g + P d 100 wt%
A conductor composition was obtained in exactly the same manner except that 2 wt % of α-ApzOs having an average particle size of 1.5 mm was added.

Using the paste compositions of Examples 1 to 7 of the present invention and Comparative Example 1, substrates having conductors were manufactured by the following method.

First, α-alumina: 40wt%, glass powder: 60w
A green sheet with a thickness of ioo to 300 t% was prepared with a composition of
s Si Oz-MO system, where M=Ca% BaS
(Sr, Mg) Next, a conductive paste was applied to this green sheet by screen printing at a shrinkage rate of 15%, and the size after firing was 2 m.
The pad was printed to have a size of m×2 mm and a film thickness of 12±2P.

Next, in order to obtain mechanical strength of the substrate, this sheet and several other unprinted sheets were laminated by hot pressing to obtain a green sheet laminate.

Thereafter, this laminate was degreased and co-fired in air at a temperature of 900° C. to produce a substrate having a conductor.

For each of the obtained substrates, the initial adhesion strength of the conductor and after aging, the solder wettability of the conductor, and the amount of warpage were examined. The results are shown in Table 1 below.

Note that the adhesive strength test was based on the peel test of Teyubon.

Stretch a copper wire with a diameter of 0.8 mm in the horizontal direction of the conductor film and solder the part that overlaps with the conductor film, and then connect the copper wire extending from one end of the soldered end to the conductor film almost perpendicular to the surface to which the conductor film is applied. The membrane was pulled in the direction of peeling using a tensile tester, and the load at the time of peeling was read.

For aging, the sample was left in a constant temperature bath at 150°C for a predetermined period of time.

Further, solder wettability was evaluated by immersing each sample in molten solder at 230'C for about 5 seconds and evaluating the wetted area ratio of the pad.

Furthermore, when calculating the amount of warpage, use a sample with one layer of conductors on the board, and place the board flat on a flat surface with the conductor facing upward. Find the height between the lower surface and the upper surface of the conductor, which indicates the pore height,
The amount of warpage (mm) was calculated (the substrate thickness at this time was 0.30 m)
As is clear from Table 1 above, all of the conductors according to the present invention showed less decrease in adhesive strength to the substrate even after a long period of time than those of the comparative examples (and less warpage). confirmed.

<Effects of the Invention> According to the paste composition and conductor of the present invention, by containing a predetermined oxide in the conductor after firing, an anchoring effect is produced at the interface between the substrate and the conductor, and these properties are maintained for a long period of time. High adhesive strength can be obtained.

Also, there is less warping.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a multilayer wiring board having a conductor according to the present invention. Explanation of symbols 1...Multilayer wiring board 2...Inner conductor 3...Outer conductor 4...Board 5...Through hole 6...Solder 7...Surface mount component 8...Resistance 9...Insulating coating layer Applicant: TDTK Co., Ltd. Representative: Patent attorney: Yo Ishii - Patent attorney: Masu 1) Tatsuya FIG.

Claims (7)

[Claims] (1) Ag or Ag alloy, Al, Cu, Ca, Sr
, two or more compounds of different metal species selected from oxides of metal compounds of one or more metals such as Mg and Ba and/or their precursor compounds (however, in the case where the two or more metals are Al + Cu) A conductive paste characterized by containing (excluding) (2) Ag, Pd, Al, Cu, Ca, Sr, Mg
and oxides of different metal compounds of one or more metals of Ba and/or compounds of two or more different metal types selected from the precursor compounds thereof (excluding cases where the two or more metals are Al + Cu) ) A conductive paste characterized by containing. (3) The metal species of the two or more compounds are Al and/or
The conductor paste according to claim 1 or 2, which is Cu and one or more of Ca, Sr, Mg and Ba. (4) The content of the two or more types of compounds is such that when the paste composition is fired to form a conductor, 1 oxide is present in the conductor.
Claims 1 to 3 wherein the content is ~12 wt%.
A conductor paste as described in any of the above. (5) the two or more compounds contain Al and Cu,
The oxide of Al and Cu is copper aluminate or
The conductive paste according to any one of claims 1 to 4, which is copper aluminate and alumina. (6) A conductor formed on the surface and/or inside of a low-temperature fired ceramic substrate by co-firing, the composition of which is Ag or Ag-based alloy, Al, Cu, Ca, S
r, two or more metals of Mg and Ba (however, Al+
A conductor characterized by containing an oxide of Cu). (7) The content of the oxides of the two or more metals is 1 to 8w.
7. The conductor according to claim 6, wherein the conductor is t%.