JP2004288622A - Manufacturing method of conductive paste and substrate with conductive layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make warping of a substrate small when a conductive paste is coated on the surface of a green sheet made of a glass ceramic composition and the conductive paste is calcined together with this green sheet, and the substrate with conductive layer is manufactured. <P>SOLUTION: The conductive paste is composed of a conductive powder in which Y is adhered 0.05-1.0 parts by mass as Y<SB>2</SB>O<SB>3</SB>to a metal powder 100 parts by mass and which is produced by the following method and an organic varnish. (Method); The metal powder is dispersed in water, which is then mixed with yttria saline solution, and PH is made 7-9, then, the liquid is filtered, and the obtained powder is heated at 100-700°C and thereby, the conductive powder is made. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a conductive paste suitable for forming a conductive layer such as wiring on a so-called LTCC substrate (low temperature co-fired ceramic substrate), and a substrate with a conductive layer suitable for manufacturing an LTCC substrate on which the conductive layer is formed. It relates to a manufacturing method.

Conventionally, alumina substrates prepared by sintering alumina powder have been widely used for electronic circuit boards.
However, in the alumina substrate, since the sintering temperature of the alumina powder is as high as about 1600 ° C., the material of the electrode to be fired simultaneously with the production of the alumina substrate is as high as W (melting point: 3400 ° C.), Mo (melting point: 2620 ° C.) Only melting point metals could be used. Therefore, there is a problem that a metal having a small specific resistance but a melting point of 1600 ° C. or less, typically Ag (melting point: 962 ° C.) cannot be used as the material of the electrode.

In order to solve such problems, various glass ceramic compositions for LTCC substrates that can be sintered at 950 ° C. or lower have been developed.
Usually, these glass ceramic compositions are green sheets, and a conductive paste layer is printed thereon to form a conductive paste layer, and then the green sheet and the conductive paste layer are simultaneously fired to form a substrate with a conductive layer. The

However, there is a case where deformation such as warpage occurs in the substrate with the conductive layer due to the large mismatch between the shrinkage characteristics when the green sheet and the conductive paste layer are sintered. In order to suppress such deformation, a silver powder is disclosed in which the shrinkage due to sintering is small and the shrinkage start temperature of the conductive paste can be increased (see, for example, Patent Document 1).
Electronic circuit boards are also required to have high mechanical strength, and a glass powder in a glass ceramic composition in which crystals are precipitated during firing is disclosed (for example, see Patent Document 2).

JP 2001-240901 A (pages 2 to 5)

JP 2002-220256 A (Table 1)

In recent years, there has been a demand for an LTCC substrate that is manufactured using a glass ceramic composition containing a glass powder that precipitates crystals upon firing, and that does not cause the above-described deformation problems, in order to increase mechanical strength. Yes.
An object of this invention is to provide the conductive paste which solves such a subject, and the manufacturing method of a board | substrate with a conductive layer.

The present invention is a conductive paste consisting essentially of a conductive powder and an organic varnish in which Y is attached as Y ₂ O _{3 in} a proportion of 0.05 to 1.0 part by mass with respect to 100 parts by mass of the metal powder. The conductive paste is produced by the following method, and a conductive paste is provided.
(Method)
A slurry in which a metal powder having a mass average particle diameter (D ₅₀ ) of 0.1 to 5.0 μm is dispersed in water and an aqueous yttrium salt solution are mixed to obtain a mixed solution, and the pH of the mixed solution is less than 7 or If it exceeds 9, adjust the pH to 7-9, and if the pH of the mixture is 7-9, filter the mixture or the mixture without adjusting the pH. The obtained powder is heated to 100 to 700 ° C. to obtain a fired powder, and then the fired powder is washed with an acid to obtain a conductive powder.

  In addition, a conductive paste is applied to at least one surface of a substrate-like molded body obtained by molding a glass ceramic composition consisting essentially of 40 to 90% glass powder and 10 to 60% ceramic filler in a mass percentage display. A method for producing a substrate with a conductive layer by firing a substrate-like molded body with a conductive paste layer produced by coating, wherein the glass powder has a glass transition point of 690 to 800 ° C. and crystallizes upon firing. The present invention provides a method for manufacturing a substrate with a conductive layer, wherein the conductive paste is the conductive paste.

  According to the present invention, it is possible to obtain a substrate with a conductive layer that can be manufactured by co-firing at a temperature of 950 ° C. or less and has a small warpage.

  The conductive paste of the present invention (hereinafter referred to as the paste of the present invention) is usually a substrate such as an alumina substrate or a glass ceramic substrate, or a glass ceramic composition substrate-like molded body (for example, a green sheet) to be fired to become a substrate. A conductive paste layer (hereinafter referred to as “paste layer”) is applied thereon by a method such as screen printing, and is then baked typically at a temperature of 950 ° C. or lower to form a conductive layer such as a wiring.

Next, the component of the paste of this invention is demonstrated using the mass percentage display content.
The conductive powder in which Y adheres to the metal powder is a conductivity imparting component and is essential. If the adhesion ratio C _{Y of Y} to the metal powder is less than 0.05 parts by mass with respect to 100 parts by mass of the metal powder, the mismatch between the shrinkage characteristics of the paste layer and the substrate-shaped molded body becomes large. Preferably it is 0.1 mass part or more, More preferably, it is 0.2 mass part or more. If it exceeds 1.0 part by mass, the specific resistance of the conductive layer becomes large. Preferably it is 0.6 mass part or less, More preferably, it is 0.4 mass part or less. Incidentally, _{C Y} can be measured for example using ICP emission spectrometry.
The conductive powder adheres at a ratio of 0.03 to 0.70 parts by mass as P ₂ O _{5 with} respect to 100 parts by mass of the metal powder, for example, when it is desired to reduce the mismatch of the shrinkage characteristics. Preferably it is.

  The content of the conductive powder is preferably 75 to 95%. If it is less than 75%, the conductivity may be insufficient. More preferably, it is 80% or more. If it exceeds 95%, the organic varnish is reduced and the applicability (printability) of the paste may be lowered. More preferably, it is 90% or less, and particularly preferably 86% or less.

The organic varnish is obtained by dissolving an organic resin having a binder function in a solvent, and is an application property imparting component and is essential.
The organic varnish content is preferably 5 to 25%. If it is less than 5%, the coatability is lowered, and for example, printing may be difficult. More preferably, it is 10% or more, and particularly preferably 14% or more. If it exceeds 25%, the printing accuracy during printing may decrease, or the sinterability may decrease, making it difficult to densify the conductive layer and increasing the specific resistance. More preferably, it is 20% or less.

Examples of the organic resin include ethyl cellulose resin, acrylic resin, styrene resin and the like that are easily available.
Examples of the solvent include α-terpineol, butyl carbitol, butyl carbitol acetate, phthalate and the like which are easily available and easily dissolve the organic resin exemplified above.
The paste of the present invention consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired.
For example, you may contain electroconductive powder other than the electroconductive powder which Y has adhered to the said metal powder. The content of such conductive powder is preferably 20% or less, more preferably 15% or less.

Next, a method for producing the conductive powder will be described.
(1) Preparation of metal powder water slurry Metal powder is dispersed in water to form a metal powder water slurry. The metal powder concentration in the slurry is preferably 50 to 300 g / L, more preferably 100 to 200 g / L.
In the slurry, P (phosphorus) is adhered to the surface of the metal powder, or a P-containing layer is formed on the surface, thereby making Y ₂ O ₃ adhesion to the metal powder described later stronger. One or more phosphoric acid compounds selected from the group consisting of phosphorous acid, water-soluble phosphite, hypophosphorous acid and water-soluble hypophosphite may be contained. When the phosphoric acid compound is contained, the total content is preferably 0.3 to 1.3 parts by mass as P ₂ O _{5 with} respect to 100 parts by mass of the metal powder.

The mass average particle size (D ₅₀ ) of the metal powder is 0.1 to 5.0 μm. If the thickness is less than 0.1 μm, the metal powder tends to aggregate, resulting in a decrease in printing accuracy or a large variation in shrinkage during sintering. Preferably it is 0.2 micrometer or more, More preferably, it is 0.3 micrometer or more. If it exceeds 5.0 μm, the shrinkage ratio at the time of sintering becomes too small, for example, the difference from the same shrinkage ratio of the green sheet becomes large, and the deformation during firing described above increases, or the specific resistance of the conductive layer increases. To do. Preferably it is 1.0 micrometer or less, More preferably, it is 0.7 micrometer or less. Note that D is measured by, for example, a laser diffraction particle size distribution meter.
When it is desired to further increase the dispersibility of the metal powder in the slurry, the metal powder is preferably spherical particles, and it is preferable to use a metal powder having a small variation in particle size.

  The metal powder preferably contains 90% or more of Ag in terms of mass percentage. If it is less than 90%, the specific resistance of the conductive layer may increase. The preferable metal powder is silver powder, silver alloy powder, mixed powder of silver powder and silver alloy powder, or mixed powder of silver powder and / or silver alloy powder and other metal powder. Examples of the silver alloy powder include silver platinum alloy powder, silver palladium alloy powder and silver rhodium alloy powder, and examples of the other metal powder include gold powder and platinum powder.

(2) Mixing of the metal powder water slurry and the yttrium aqueous solution While stirring the metal powder water slurry, the yttrium aqueous solution is added thereto and mixed. The temperature is preferably 30 to 60 ° C.
Examples of the yttrium aqueous solution include an aqueous solution of a water-soluble yttrium salt such as yttrium nitrate, a solution obtained by dissolving a water-insoluble yttrium salt such as yttrium oxide, yttrium hydroxide, and yttrium carbonate in nitric acid.
The Y ₂ O ₃ content of the yttrium aqueous solution is preferably 0.5 to 4 parts by mass with 100 parts by mass of the metal powder in the metal powder water slurry. If the amount is less than 0.5 parts by mass, the metal powder may be sintered in the firing step described later. More preferably, it is 1 part by mass or more. Even if it contains exceeding 4 mass parts, only the effect similar to the case where it contains 4 mass parts is exhibited. Preferably it is 3 mass parts or less.

(3) Adjusting the pH of the mixture When the pH of the mixture of the metal powder water slurry and the yttrium aqueous solution is less than 7 or more than 9, add an alkali (for example, sodium hydroxide) or acid to the mixture to adjust the pH to 7-9. To. In addition, when the pH of the said liquid mixture is already 7-9, it is not necessary to adjust the pH of a liquid mixture, However, You may adjust pH in the range.

(4) Filtration of mixed liquid and washing / drying of separated powder It is preferable but not essential to perform filtration of mixed liquid and washing / drying of separated powder described here.
The mixture is filtered at a pH of 7-9 to separate the powder.
Next, the separated powder, that is, the separated powder is washed. Washing is preferably performed using water, and more preferably, further washing is performed using a water-soluble organic solvent such as methanol, ethanol, or isopropanol. In addition, by performing water-soluble organic solvent cleaning, drying described later can be efficiently performed at less than 100 ° C.
Next, the washed separated powder is dried. Drying is preferably performed at less than 100 ° C. If it exceeds 100 ° C, the powder tends to aggregate.

(5) Heating of the mixed solution or separated powder When the mixed solution prepared in (3) with a pH of 7-9 or the separated powder obtained in (4), the separated powder is heated to 100-700 ° C. To produce a fired powder.
Heating is preferably performed in a nitrogen stream or the like in order to suppress or prevent oxidation during heating.
When heating the separated powder, the heating time is typically 0.5 to 2 hours. The separated powder is heated using a rotary furnace, a fluidized furnace, a stationary furnace, or the like. Since the separated powder is agitated during heating, it is preferable to use a rotary furnace or a fluidized furnace.
By performing such heating, the specific resistance of the conductive powder can be lowered as compared with the case where such heating is not performed.

(6) Cleaning of baked powder The cleaning of the baked powder described here is for the purpose of removing Y or yttrium compounds that are not attached to the metal powder, adjusting the adhesion rate of Y to the metal powder, etc. It is done and not required.
The calcined powder is dispersed in water to prepare a slurry, and an acid such as nitric acid or acetic acid is added thereto to remove a desired amount of Y or yttrium compound.
Next, the slurry is filtered to separate the powder, and the separated powder is washed and dried as described in (4).

The specific resistance of the fired product obtained by firing the paste of the present invention is preferably 4 μΩ · cm or less. More preferably, it is 3 μΩ · cm or less.
The paste of the present invention is manufactured by a known paste manufacturing method. It is manufactured by mixing conductive powder and organic varnish using, for example, a three-roll mill.

Next, the manufacturing method of the board | substrate with a conductive layer of this invention is demonstrated.
First, the components of the glass ceramic composition will be described using the mass percentage display content.
A glass transition point Tg of 690 to 800 ° C., and a glass powder that crystallizes upon firing (hereinafter referred to as the present glass powder) is a component that increases the denseness of the fired body (substrate) and is essential. If the glass powder is less than 40%, the denseness of the fired body is insufficient. Preferably it is 50% or more, more preferably 55% or more. If it exceeds 90%, the strength of the fired body is insufficient. Preferably it is 70% or less.

If the Tg is less than 690 ° C., the fluidity during firing becomes excessive. If it exceeds 800 ° C., the density of the fired product is lowered when it is fired at a temperature of 950 ° C. or lower. Preferably it is 760 degrees C or less, More preferably, it is 730 degrees C or less.
If it does not crystallize during firing, the strength of the fired body is reduced. Whether the glass powder is crystallized can be determined by X-ray diffraction or differential thermal analysis.
The glass powder is preferably crystallized when fired at a temperature of 950 ° C. or lower, and more preferably crystallized when fired at a temperature of 900 ° C. or lower.
When ε _G or tan δ _G, which will be described later, is desired to be smaller, the crystal precipitated when crystallization is composed of cordierite, diopside, anorthite, enstatite, forsterite, and BaAl ₂ SiO _8. One or more crystals selected from the group are preferred.

The present glass powder is expressed in terms of mol% based on the following oxides: SiO ₂ 35 to 55%, Al ₂ O ₃ 0.5 to 20%, MgO 5 to 40%, CaO 5 to 40%, B ₂ O ₃ 0 It preferably consists essentially of -10% and ZnO 0-10%. In this preferred embodiment, components other than the above components may be contained within a range not impairing the object of the present invention, but when such components are contained, the content is preferably less than 10 mol% in total. .

_{D 50} of the glass powder is preferably from 0.5 to 15 m. If it is less than 0.5 μm, the storage stability of a substrate-like molded product such as a green sheet may be lowered. If it exceeds 15 μm, the sinterability may decrease.

The relative dielectric constant ε _G at 20 ° C. and 35 GHz of the crystal precipitation fired body obtained by firing the present glass powder is preferably 8 or less. Note that ε _G is typically 4 or more.
Further, the dielectric loss tan δ _G at 20 ° C. and 35 GHz of the crystal precipitation fired body is preferably 0.0070 or less. More preferably, it is 0.0055 or less, Most preferably, it is 0.0030 or less. Note that tan δ _G is typically 0.0010 or more.
The crystal precipitation fired body is preferably obtained by firing at 900 ° C.

The ceramic filler is a component that increases the strength of the fired body and is essential. If it is less than 10%, the strength is insufficient. Preferably it is 20% or more. If it exceeds 60%, the denseness of the fired product is insufficient. Preferably it is 50% or less, More preferably, it is 40% or less.
When it is desired to reduce the tan δ (described later) of the fired body, the ceramic filler is α-alumina (melting point = 2050 ° C.), cordierite (melting point = 1460 ° C.), forsterite (melting point = 1890 ° C.), enstatite. It is preferably a powder of one or more inorganic substances selected from the group consisting of (melting point = 1550 ° C.) and spinel (melting point = 2050 ° C.). More preferably, α-alumina powder is contained.

The D ₅₀ of the ceramic filler is preferably 1 to 20 μm. If it is less than 1 μm, the fluidity is lowered, and the denseness of the fired product may be insufficient, or the strength of the fired product may be insufficient. More preferably, it is 2 μm or more, particularly preferably 5 μm or more, and most preferably 7 μm or more. If it exceeds 20 μm, the degree of mixing may decrease, or the strength of the fired product may be insufficient. More preferably, it is 15 micrometers or less, Most preferably, it is 12 micrometers or less.

The glass ceramic composition consists essentially of the above components, but may contain other components as long as the object of the present invention is not impaired. The content of the other components is preferably 10% or less in total, more preferably 7% or less.
Examples of the other components include heat-resistant color pigments, cerium oxide powder, boron oxide powder, copper oxide powder, silver oxide powder, titanium oxide powder, and zinc oxide powder.

The glass-ceramic composition is formed into a substrate shape to form a substrate-shaped formed body. In addition, the said board-shaped molded object is a green sheet normally.
The glass ceramic composition is formed into a green sheet as follows, for example. That is, the glass ceramic composition includes a resin such as polyvinyl butyral and acrylic resin, a solvent such as toluene, xylene, and butanol, and a plasticizer such as dibutyl phthalate, dioctyl phthalate, and butyl benzyl phthalate as necessary. Add a dispersing agent and mix to make a slurry, then form the slurry on a film of polyethylene terephthalate (PET) etc. by a doctor blade method etc., then dry to remove the solvent, A sheet.

Next, the paste of the present invention is applied to at least one surface of the substrate-like molded body by screen printing or the like to form a conductive paste layer in a wiring pattern, for example.
The substrate-like molded body with a conductive paste layer thus produced is fired to obtain a substrate with a conductive layer. In the substrate with a conductive layer, the conductive layer corresponds to the fired body of the conductive paste layer, and the substrate corresponds to the fired body of the substrate-like molded body.
The maximum temperature during firing is preferably 950 ° C. or lower. It is typically 850 to 950 ° C. More preferably, the maximum temperature is 900 ° C. or lower.
The firing condition is typically maintained at 850 to 950 ° C. for 5 to 180 minutes.

  The relative permittivity ε and dielectric loss tan δ of the substrate-like molded body with a conductive paste layer or the fired body of the glass ceramic composition are 8.6 or less and 0.0020 or less at 20 ° C. and 35 GHz, respectively. preferable. Note that ε and tan δ are typically 4 or more and 0.0005 or more, respectively.

  The method for producing a substrate with a conductive layer of the present invention is not limited to the above-described method. For example, another substrate-shaped molded body with a conductive paste layer is stacked on a substrate-shaped molded body with a conductive paste layer, for example, 100 Heating to ~ 150 ° C., pressing, and subsequent firing may produce a substrate with a two-layer type conductive layer, or a multilayer type substrate with a conductive layer of three or more layers may be produced in the same manner .

  The warp of the substrate with a conductive layer by the method for manufacturing a substrate with a conductive layer of the present invention is preferably 75 μm / cm or less even if it exists. If it exceeds 75 μm / cm, mounting of a bare chip, bonding to a base substrate and the like may be difficult. More preferably, it is 50 μm / cm or less, and particularly preferably 25 μm / cm or less. A method for measuring the warpage will be described later.

SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , MgO, CaCO ₃ , ZnO are used as a glass raw material, and SiO ₂ is 44%, Al ₂ O ₃ is 8%, MgO in terms of mol% based on oxide. Was mixed in a platinum crucible, melted at 1500 ° C. for 120 minutes, poured out, and cooled. The obtained glass was ground by a ball mill made of alumina D ₅₀ to obtain a glass powder A of 2.5 [mu] m. D ₅₀ was measured with a laser diffraction particle size distribution analyzer SALD2100 manufactured by Shimadzu Corporation using water as a solvent.

The Tg and the crystallization peak temperature _{T C} of the glass powder A, measured by using a Mac Science Corp. Differential Thermal analyzer TG-DTA, 720 ° C., respectively, was 948 ° C..
Moreover, as a result of investigating the presence or absence of crystal precipitation by the X-ray diffraction method for the fired body obtained by maintaining the glass powder A at 900 ° C. for 30 minutes, precipitation of anorthite, diopside and forsterite was observed.

Both were mixed such that the glass powder A was 65% and the alumina powder (Sumitomo Random AA10 manufactured by Sumitomo Chemical Co., Ltd.) was 35% in terms of mass percentage, and a glass ceramic composition as a mixed powder thereof was produced.
To 100 parts by mass of this glass ceramic composition, 70 parts by mass of an organic solvent composed of toluene, xylene, isopropyl alcohol and n-butyl alcohol, 5 parts by mass of dibutyl phthalate, and 0.5% of a dispersant (BYK180 manufactured by BYK Chemie) are added. A smooth slurry was obtained by adding and mixing at a mass part ratio.
This slurry was applied onto a PET film by a doctor blade method and dried to prepare a green sheet having a thickness of about 200 μm.

Next, a paste was produced as follows.
First, a silver powder 1 having a spherical shape when observed with a scanning electron microscope and having a particle size of about 0.5 μm was prepared.
150 g of silver powder 1 was dispersed in 1 L of pure water and stirred to prepare a silver powder water slurry.
To this silver powder water slurry, an aqueous yttrium chloride solution containing 3.75 g of Y as Y ₂ O ₅ was added and stirred for 30 minutes to prepare a mixed solution.
A sodium hydroxide aqueous solution was added to the mixture to adjust the pH to 8.
The pH 8 mixture was filtered, and the powder separated by filtration was washed and dried to obtain a separated powder.
150 g of the separated powder was put in an electric furnace, kept at 300 ° C. for 1 hour while flowing nitrogen gas, and then cooled to obtain a fired powder.

  This baked powder is divided into three equal parts, and 3.9 mL, 3.2 mL, and 1.9 mL of glacial acetic acid are added to each of the three baked powders, followed by stirring for 1 hour, followed by filtration, washing, and drying. 2, Silver powder 3 and Silver powder 4 were obtained. The adhesion ratio of Y to the silver powder in the silver powders 2, 3, and 4 was measured using ICP emission analysis. As a result, 100 parts by mass of the silver powder was 0.2 parts by mass, 0.3 parts by mass, and. It was 5 parts by mass.

Further, as the silver powder 5 was prepared MITSUI MINING & SMELTING Co. _Al 2 _{O 3} coated silver _{powder Al} 2 _{O 3} is deposited in a proportion of 0.3 part by weight of silver powder 100 parts by weight.

In addition, 150 g of silver powder 1 was dispersed in 1 L of pure water, a sodium silicate solution was added while maintaining the temperature at 50 ° C., the mixture was stirred for 1 hour, and nitric acid was added to adjust the pH to 8. Thereafter, filtration and drying were performed to obtain silver powder 6. The silver powder 6 was measured using ICP emission spectrometry, Si was deposited at a rate of 0.3 parts of silver powder 100 parts by SiO _2.

  Both are prepared so that the silver powder 1 is 85% by mass and the organic varnish obtained by dissolving ethyl cellulose in α-terpineol at a mass ratio of 1: 9 is 15%. After kneading in a porcelain mortar for 1 hour, Dispersion was performed three times with this roll to prepare paste 1. Similarly, pastes 2-6 were prepared using silver powders 2-6. Pastes 2, 3, and 4 are examples, and pastes 1, 5, and 6 are comparative examples.

  Six green sheets obtained by cutting the green sheet into 4 cm × 4 cm are stacked, heated to 110 ° C. and pressed, and pastes 1 to 6 are used on the surface of the green sheet laminate (reference numeral 1 in FIG. 1). A comb-like wiring pattern (paste layer) 2 as shown in FIG. 1 was printed and fired at 900 ° C. for 1 hour to obtain a fired body (substrate with conductive layer) on which silver conductor wiring was formed. The thickness of the fired body was 0.9 mm.

The warpage of the fired body was measured as shown in FIG. That is, the thickness t, width a, and height b of the fired body were measured using calipers, and the warpage (unit: μm / cm) was calculated according to the following formula. In addition, 3 is a conductor wiring and 4 is a board | substrate.
Warpage = {(b−t) / a} × 10000
In addition, the electrical resistance R was measured using a digital multimeter manufactured by Advantest Co., Ltd., and the cross-sectional area S was calculated by an integration method using a surfcom manufactured by Tokyo Seimitsu Co., Ltd. Moreover, the length L of the silver conductor wiring was measured with a digital caliper with an optical microscope.
The specific resistance (unit: μΩ · cm) was calculated from the R, S, and L by the following equation.
Specific resistance = R × S ÷ L

The figure explaining the manufacturing method of the measurement sample of the curvature of the sintered compact in which conductor wiring was formed. The figure explaining the measuring method of the curvature of the sintered compact in which conductor wiring was formed.

Explanation of symbols

1: Green sheet laminate 2: Printed comb pattern wiring (paste layer)
3: Conductor wiring 4: Board

Claims (7)

A conductive paste consisting essentially of a conductive powder and an organic varnish adhering at a ratio of 0.05 to 1.0 part by mass as Y ₂ O _{3 with} respect to 100 parts by mass of the metal powder, A conductive paste, wherein the conductive powder is prepared by the following method.
(Method)
When a slurry in which a metal powder having a mass average particle size of 0.1 to 5.0 μm is dispersed in water and an aqueous yttrium salt solution are mixed to form a mixed solution, and the pH of the mixed solution is less than 7 or more than 9, The pH is adjusted to 7 to 9, and when the pH of the mixture is 7 to 9, the mixture or the powder obtained by filtering the mixture is filtered without adjusting the pH. It heats to 100-700 degreeC, is set as a baked powder, and the baked powder is acid-washed after that, and is set as electroconductive powder.   The conductive paste according to claim 1, wherein the metal powder contains 90% or more of Ag in terms of mass percentage. A conductive paste is applied to at least one surface of a substrate-like molded body in which a glass ceramic composition essentially composed of 40 to 90% glass powder and 10 to 60% ceramic filler is formed into a substrate shape in terms of mass percentage. A method for producing a substrate with a conductive layer by firing a substrate-like molded body with a conductive paste layer produced in a step,
The glass powder has a glass transition point of 690 to 800 ° C. and crystallizes upon firing, and the conductive paste is the conductive paste according to claim 1 or 2, Production method.   The maximum temperature at the time of baking is 850-950 degreeC, The board | substrate manufacturing method with a conductive layer of Claim 3 characterized by the above-mentioned.   5. The specific dielectric constant and dielectric loss of a substrate obtained by firing the substrate-shaped molded body are 8.6 or less and 0.0020 or less at 20 ° C. and 35 GHz, respectively. 6. A method for manufacturing a substrate with a conductive layer. Glass powder represented by mol% based on the following _{oxides, SiO 2 35~55%, Al 2} O 3 0.5~20%, 5~40% MgO, CaO 5~40%, B 2 O 3 0~10 %, ZnO 0 to 10%, and the method for producing a substrate with a conductive layer according to claim 3, 4 or 5. The substrate with conductive layer according to claim 3, 4, 5, or 6, wherein the ceramic filler is one or more inorganic powders selected from the group consisting of α-alumina, cordierite, forsterite, enstatite, and spinel. Method.

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