CN115136257A - Conductive paste and conductive pattern using the same - Google Patents

Abstract

An object of the present invention is to provide a conductive paste and a conductive pattern using the conductive paste, which enables printing of a conductive pattern with little variation in line width and high precision, and also has high electrical conductivity and thermal conductivity in the printed conductive pattern. properties, high migration resistance, etc. According to the present invention, as a conductive paste, a silver-coated copper sheet is used as a base, and silver-coated silica powder is added thereto, thereby providing a conductive paste comprising a silver-coated copper sheet and silver-coated silica powder, and a conductive paste using the conductive paste. conductive pattern. Furthermore, the conductive paste of the present invention may further contain a binder resin, a solvent, and a curing agent.

Description

Conductive paste and conductive pattern using the same

technical field

The present invention relates to a conductive paste for forming a conductive pattern such as an electrode of an electronic device, and a conductive pattern using the conductive paste.

Background technique

In order to mount and fix semiconductor elements (semiconductor chips) such as ICs and LSIs on metal sheets called lead frames, to form circuits on substrates by printing or the like, or to form electrodes for electronic components such as capacitors, etc. Conductive paste is used in this application.

In addition, with the recent improvement in the degree of integration of semiconductor chips and the increase in the density of circuits on circuit boards, conductive pastes are required to print circuit patterns with little variation in line width and high precision, and to print circuit patterns with high precision. Also in the circuit pattern of , it has high electrical conductivity and thermal conductivity, has high migration resistance, and has excellent workability by having moderate viscosity and fluidity.

For example, Japanese Patent Laid-Open No. 2012-18783 (Patent Document 1) discloses a conductive paste in which silver particles having an average primary particle diameter of 10 nm or more and 200 nm or less are added to silver particles having an average particle diameter of 0.5 μm or more. The flowability of the conductive paste is suppressed from decreasing, so that the wiring of the conductive film having a low volume resistivity can be formed, and the adhesion to the substrate and the printability can be improved.

In addition, JP Patent Publication No. 2019-102273 (Patent Document 2) discloses a conductive paste that has an appropriate viscosity that maintains a thin wire shape as much as possible while maintaining a low electrical resistance electrically, by using a conductive paste containing 3 kinds of fillers of nanoparticles, thereby suppressing the decrease in viscosity.

However, in the conductive pastes described in Patent Documents 1 and 2, it is difficult to disperse the nano-sized fillers, and the fluidity tends to be high. When the fluidity is too high, there is a problem in that the conductive paste is impregnated after printing, causing variation in the line width, resulting in a short circuit of the circuit. In addition, the conductive patterns formed using these conductive pastes also have a problem that they do not necessarily have high migration resistance.

In addition, when the filling amount of conductive powder such as silver particles increases, it becomes difficult to disperse. For this reason, conventional compositions highly filled with flake (or flat) silver powder, spherical silver powder, and the like tend to have poor appearance. There are also problems such as a decrease in adhesive strength and workability.

prior art literature

Patent Literature

Patent Document 1: JP Patent Publication No. 2012-18783

Patent Document 2: JP Patent Publication No. 2019-102273

SUMMARY OF THE INVENTION

Invention to solve the problem

Therefore, an object of the present invention is to provide a conductive paste and a conductive pattern (circuit pattern) using the conductive paste, which can print the conductive pattern with little deviation in line width and high accuracy, and in the printed conductive pattern , also has high electrical conductivity and high migration resistance, and has excellent workability by having moderate viscosity and fluidity.

means of solving problems

In view of the above-mentioned problems, the present inventors have developed a type and shape of conductive powder for achieving high electrical conductivity and excellent workability while suppressing the occurrence of line width variation and migration due to impregnation during printing. As a result of intensive research on the combination with different conductive powders, etc., it was found that, as a conductive paste, silver-coated copper flakes (flake) as a base and silver-coated silica powder added to it can solve the problem. As a result of the above-mentioned problems, the present inventors have completed the present invention.

That is, according to the present invention, a conductive paste containing silver-coated copper flakes and silver-coated silica powder, and a conductive pattern using the conductive paste can be provided. In addition, the conductive paste of the present invention may further contain a binder resin, a solvent, and a curing agent.

The conductive paste of the present invention is a composition formed into a paste by adding silver-coated copper flakes and silver-coated silica powder and adding a binder resin to them. As long as the silver-coated copper sheet, the silver-coated silica powder, and the binder resin are contained, other components such as a solvent and an antifoaming agent may be contained as necessary within a range that does not impair the effects of the present invention.

The silver-coated copper sheet used in the present invention is not particularly limited as long as it is a sheet-like copper powder coated with silver, and known materials can be used. The volume average particle diameter (D ₅₀ ) of the silver-coated copper sheet is preferably 1.0 μm or more and 50 μm or less, and more preferably 2.0 μm or more and 20 μm or less. In particular, as long as the volume average particle diameter (D ₅₀ ) of the silver-coated copper sheet is 2.0 μm or more and 20.0 μm or less, it is extremely easy to deal with thin lines when drawing circuits. In addition, as copper powder coated with silver, spherical or substantially spherical copper powder or sheet-like copper powder is known, but from the viewpoint of suppressing the reduction of electrical contacts after circuit formation and suppressing the increase in resistance, the In the present invention, a silver-coated copper sheet is preferably used.

In addition, the silver-coated copper sheet may be completely covered with silver, or a part of copper may be exposed. The case where it is completely covered with silver is suitable because the resistivity value becomes small. The compounding amount of the silver-coated copper sheet is preferably 10% by volume or more and 40% by volume or less with respect to the total nonvolatile content of the conductive paste, and more preferably 30% by volume or more and 40% by volume or less. As long as the blending amount of the silver-coated copper sheet is 10% by volume or more and 40% by volume or less, the resistivity value can be kept low, and workability can be improved by having moderate viscosity and fluidity.

The silver-coated silica powder used in the present invention is not particularly limited as long as it is a silica powder coated with silver, and known materials can be used. The volume average particle diameter (D ₅₀ ) of the silver-coated silica powder is preferably 0.050 μm or more and 50.0 μm or less, and more preferably 0.1 μm or more and 5.0 μm or less. In particular, as long as the volume average particle diameter (D ₅₀ ) of the silver-coated silica powder is 0.1 μm or more and 5.0 μm or less, the resistivity value can be kept low by achieving a high filling rate.

In addition, the silver-coated silica powder may be completely covered with silver, or a part of the silica may be exposed. The case where it is completely covered with silver is suitable because the resistivity value becomes small. Regarding the compounding amount of the silver-coated silica powder, the volume ratio of the silver-coated copper flakes to the silver-coated silica powder is preferably in the range of 99:1 to 15:85, and more preferably in the range of 99:1 to 20:80. scope.

As long as the volume ratio of the silver-coated copper flakes to the silver-coated silica powder is in the range of 99:1 to 15:85, the fluidity of the resulting conductive paste is particularly suitable, and the deviation of lines during printing is reduced. Along with this, the electrical conductivity and migration resistance of the formed circuit pattern are also improved. In addition, the shape of the silver-coated silica powder can be used without particular limitation as long as it is a particle. As long as it is in the form of particles, it is particularly suitable for use because of its excellent fluidity.

In addition, the numerical value (ratio) range shown using "from" and "to" in the specification of this application means that the numerical value (ratio) described before and after "from" and "to" is the minimum value (ratio) and the maximum value ( ratio) and the range included.

It does not specifically limit as a binder resin used by this invention, A well-known resin can be used. As a thermosetting resin, an epoxy resin, a phenol resin, a urea resin, an unsaturated polyester resin, an alkyd resin, a polyurethane, a thermosetting polyimide, etc. are mentioned. In addition, thermoplastic resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyester, and polyamide in which functional groups remain at the terminals may be used together with a curing agent.

In order to realize workability and printability suitable for various printing methods such as screen printing, it is preferable to mix the resin binder in a ratio of 30 vol % or more and 60 vol % or less with respect to the total nonvolatile content of the conductive paste.

The solvent used in the conductive paste of the present invention is not particularly limited. It can be appropriately selected according to the solubility of the resin to be used, the type of printing method, and the like. Examples of the solvent of the present invention include ester-based solvents, ketone-based solvents, glycol ether-based solvents, aliphatic-based solvents, alicyclic solvents, aromatic-based solvents, alcohol-based solvents, and water. Or a solvent in which two or more kinds are mixed.

Moreover, ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, dimethyl carbonate, etc. are mentioned as an example of an ester type solvent. Examples of the ketone-based solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone benzene, diisobutyl ketone, diacetone alcohol, isophorone, cyclohexanone, and the like. Examples of the glycol ether-based solvent include acetates of these monoethers, such as ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, and ethylene glycol monobutyl ether, diglyme, and diethylene glycol. Diethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc., acetate esters of these monoethers, and the like.

On the other hand, n-heptane, n-hexane, isohexane, isoheptane, etc. are mentioned as an example of an aliphatic solvent. Examples of the alicyclic solvent include methylcyclohexane, ethylcyclohexane, cyclohexane, and the like. As an example of an aromatic solvent, toluene, xylene, tetralin, etc. are mentioned. Examples of the alcohol-based solvent (other than the above-mentioned glycol ether-based solvent) include ethanol, propanol, butanol, and the like.

In addition, a plurality of linear lines are printed on the PET resin sheet with an interval of about 100 μm using the above-described conductive paste of the present invention. In the circuit pattern obtained in this way, the deviation of line width is small, and therefore adjacent lines are mutually adjacent. There is no short circuit (contact), and furthermore, a circuit pattern excellent in the electrical conductivity of each line can be obtained.

effect of invention

Since the conductive paste of the present invention has a moderate viscosity and moderate fluidity, it has excellent workability, and also has the excellent effect of being able to print circuit patterns with little deviation in line width and high accuracy. , and also in the printed conductive pattern, excellent effects such as high electrical conductivity and high migration resistance can be achieved.

Description of drawings

FIG. 1 is a microscope photograph of a circuit pattern (conductive pattern) printed using the conductive paste of Example 4. FIG.

2 is a microscope photograph of a circuit pattern (conductive pattern) printed using the conductive paste of Comparative Example 1. FIG.

3 is a microscope photograph of a circuit pattern (conductive pattern) printed using the conductive paste of Comparative Example 3. FIG.

Detailed ways

Hereinafter, a conductive paste according to an embodiment of the present invention and a conductive pattern using the conductive paste will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited to the Example shown below, Various changes can be added in the range which does not deviate from the technical idea of this invention.

【Example】

1. Production of conductive paste

The conductive paste according to one embodiment of the present invention and the conductive paste of the comparative example were prepared according to the following raw materials and conditions (refer to "Table 1").

[Example 1]

The conductive paste of Example 1 was prepared by mixing the following parts, followed by kneading with a dispersant and a 3-roll mixer: As a silver-coated copper sheet, 65.1 g of TOYAL having a volume average particle size (D ₅₀ ) of 6 μm was mixed TecFiller (registered trademark)/TFM-C05F (manufactured by Toyo Aluminum Co., Ltd.); as silver-coated silica powder, 0.29 g of TOYAL _TecFiller (registered trademark)/TFM-S02P ( Toyo Aluminum Co., Ltd.); as a binder resin, 12.0 g of Elite (registered trademark)/UE-3210 (manufactured by UNITIKA) was prepared; as a curing agent, 1.7 g of blocked isocyanate (product name: 7992, Baxenden Co., Ltd.) was prepared and, as a solvent, 24.9 g of a mixed solvent obtained by mixing ethyl carbitol acetate and isophorone at a weight ratio of 16:9 was prepared.

[Example 2]

The same conditions as in Example 1 were followed except that 0.57 g of TOYALTecFiller (registered trademark)/TFM-S02P (manufactured by Toyo Aluminum Co., Ltd.) having a volume average particle diameter (D ₅₀ ) of 2 μm was prepared as the silver-coated silica powder The conductive paste of Example 2 was produced.

[Example 3]

As the silver-coated silica powder, 1.2 g of TOYAL TecFiller (registered trademark)/TFM-S02P (manufactured by Toyo Aluminum Co., Ltd.) having a volume average particle diameter (D ₅₀ ) of 2 μm was prepared in the same manner as in Example 1. conditions to produce the conductive paste of Example 3.

[Example 4]

As the silver-coated silica powder, 2.3 g of TOYAL TecFiller (registered trademark)/TFM-S02P (manufactured by Toyo Aluminum Co., Ltd.) having a volume average particle diameter (D ₅₀ ) of 2 μm was prepared in the same manner as in Example 1. conditions to produce the conductive paste of Example 4.

[Example 5]

As the silver-coated copper sheet, 25.9 g of TOYAL TecFiller (registered trademark)/TFM-C05F (manufactured by Toyo Aluminum Co., Ltd.) having a volume average particle diameter (D ₅₀ ) of 6 μm was prepared, and as the silver-coated silica powder, 32.3 g of A conductive paste of Example 5 was prepared under the same conditions as in Example 1, except that the volume average particle size (D ₅₀ ) was TOYAL TecFiller (registered trademark)/TFM-S02P (manufactured by Toyo Aluminum Co., Ltd.) of 2 μm.

[Comparative Example 1]

A conductive paste of Comparative Example 1 was produced under the same conditions as in Example 1, except that the silver-coated silica powder was not blended.

[Comparative Example 2]

The silver-coated copper flakes were not prepared, but 47.9 g of TOYAL TecFiller (registered trademark)/TFM-S02P (manufactured by Toyo Aluminum Co., Ltd.) having a volume average particle diameter (D ₅₀ ) of 2 μm was prepared as the silver-coated silica powder. The conductive paste of Comparative Example 2 was produced under the same conditions as in Example 1.

[Comparative Example 3]

The silver-coated copper flakes were not prepared, but 7.9 g of TOYAL TecFiller (registered trademark)/TFM-S02P (manufactured by Toyo Aluminum Co., Ltd.) having a volume average particle diameter (D ₅₀ ) of 2 μm was prepared as the silver-coated silica powder. The conductive paste of Comparative Example 3 was produced under the same conditions as in Example 1.

[Comparative Example 4]

In place of the silver-coated silica powder, 2.3 g of spherical silver powder (product name: HXR-Ag, manufactured by Nippon Atomize Processing Co., Ltd.) having a volume average particle diameter (D ₅₀ ) of 5.7 μm was prepared in the same manner as The conductive paste of Comparative Example 4 was produced under the same conditions as Example 1.

[Comparative Example 5]

Instead of the silver-coated copper flakes, 65.1 g of silver flakes having a volume average particle diameter (D ₅₀ ) of 4.8 μm (product name: TCG-1, manufactured by Tokuli Chemical Laboratory Co., Ltd.) were prepared as silver-coated dioxide A comparative example was prepared under the same conditions as in Example 1, except that 2.3 g of silicon powder was prepared with TOYAL TecFiller (registered trademark)/TFM-S02P (manufactured by Toyo Aluminum Co., Ltd.) having a volume average particle diameter (D ₅₀ ) of 2 μm. 5 of the conductive paste.

[Comparative Example 6]

Instead of the silver-coated copper flakes, 65.1 g of silver flakes with a volume average particle diameter (D ₅₀ ) of 4.8 μm (product name: TCG-1, manufactured by Toku Chemical Research Institute Co., Ltd.) were prepared, and no silver-coated 2 was prepared. The conductive paste of Comparative Example 6 was prepared under the same conditions as in Example 1 except for silicon oxide powder.

Table 1 shows the addition amount (g) of each component prepared as the conductive pastes of Examples 1 to 5 and Comparative Examples 1 to 6 and the compounding ratio (Vol%) of each component with respect to the total nonvolatile content of the conductive paste.

【Table 1】

2. Fabrication of circuit pattern (conductive pattern)

Using the conductive pastes of Examples 1 to 5 and Comparative Examples 1 to 6, a screen plate was produced using a circuit pattern made of stainless steel, a wire mesh of 325 meshes, an emulsion thickness of 10 μm, a line width of 100 μm, and an interval of 100 μm between lines. , using this screen plate, by a screen printing machine (product name: DP-320 type screen printing machine, made by Newlong Precision Industry Co., Ltd.), printing was carried out on a PET resin sheet. Next, the sheet on which the circuit pattern was printed was dried at 150° C. for 30 minutes to prepare a circuit pattern for evaluation.

3. Evaluation of conductive paste and circuit pattern

(1) Viscosity

In order to investigate the relationship with the workability and impregnation properties of the conductive paste, Examples 1 to 5 and comparisons were measured under the conditions of a temperature of 25° C. and a rotational speed of 0.5 rpm using a Brookfield viscometer (model: DV2THBCJ0, manufactured by Brookfield Corporation). Viscosity of the conductive pastes of Examples 1 to 6. Table 2 shows the results.

(2) Deviation of line width

The circuit patterns for evaluation prepared using the conductive pastes of Examples 1 to 5 and Comparative Examples 1 to 6 were observed and imaged using an inspection microscope (product name: ECLIPSE L200, manufactured by Nikon Corporation) at a magnification of 50 times. Next, the obtained image was subjected to binarization processing using image analysis software (product name: Winroof2018, manufactured by Mitani Shoji Co., Ltd.). From the binarized image, the line width of 1000 parts was measured, and the value of 3σ, which is an index of the deviation of the line width, was obtained. 3σ refers to an interval that is three times the standard deviation (σ), and as long as it is normally distributed, about 99.7% of the samples will be within the range of ±3σ from the mean.

The variation in the line width of the circuit pattern is preferably as small as the value of 3σ, but when the value of 3σ exceeds 50 μm, there is a possibility of short-circuiting between adjacent lines at the time of energization, so the evaluation is “×”. (defective), the case of 50 μm or less was evaluated as “◯” (good). In addition, when a short circuit (contact) was observed in a part of adjacent lines from the beginning of circuit pattern formation, it evaluated as "x" (defective), and did not depend on the value of 3σ. Table 2 shows the above results.

In addition, among the circuit patterns for evaluation described above, FIG. 1 shows a microscope photograph of a circuit pattern produced using the conductive paste of Example 4, and FIG. 2 shows a microscope photograph of a circuit pattern produced using the conductive paste of Comparative Example 1. A photograph, and FIG. 3 shows a microscope photograph of a circuit pattern produced using the conductive paste of Comparative Example 3.

(3) Migration resistance

The migration resistance of the circuit pattern was evaluated by maintaining each of the above-mentioned circuit patterns for evaluation under the conditions of 85° C., humidity of 85%, and applied voltage of 50V, and measuring the time until a short circuit occurred. The presence or absence of a short circuit in the circuit pattern was confirmed using a migration tester (product name: MODEL MIG-87B, manufactured by IMV Co., Ltd.).

The migration resistance shows that the longer the time until the short circuit occurs in the circuit pattern, the more excellent the migration resistance is. Good), and the case of less than 800 hours was evaluated as "X" (defective). Table 2 shows the above results.

(4) Resistivity value

Regarding the resistivity value (Ω·em) of the circuit pattern, a screen plate for evaluation was produced using a polyester resin, a screen mesh of 280 meshes, an emulsion thickness of 9 μm, and a quadrilateral shape of 4.8 cm×4.8 cm. With the screen plate for evaluation, the conductive paste was printed on a PET film, and dried at 150° C. for 30 minutes, and a coating film was formed on the product thus obtained. In addition, the thickness of the coating film was confirmed by measuring with a digital caliper outside micrometer (trade name: IP65COOLANTPROOF Micrometer, manufactured by Mitutoyo Co., Ltd.). This was confirmed by measuring using a 4-probe type surface resistance measuring device (trade name: LorestaGP, manufactured by Mitsubishi Analytech Co., Ltd.). In each circuit pattern for evaluation, arbitrary 5 points were measured respectively, and the average value was made into a resistivity value. Specifically, the value obtained by inputting the size of the printed matter, the average thickness of the printed matter, and the coordinate data of the measurement point into the above-mentioned 4-pin surface resistance measuring device and automatically calculating it was used as the conductor layer (circuit pattern/conductive pattern). ) resistivity value.

The resistivity value shows a characteristic that the smaller the value is, the more excellent the conductivity is. The size of the printed matter refers to the size constituted by the maximum length and the maximum width in a pattern of a given shape that the printed matter has. When the resistivity value is small, it is good, and the case where the resistivity value is less than 2.0×10 ^-4 Ω·cm is evaluated as "○" (good), and the case where the resistivity value is larger than 2.0×10 ^-4 Q·cm is evaluated as "×""(bad). Table 2 shows the above results.

Regarding the comprehensive evaluation of each circuit pattern for evaluation, in the evaluation of the above-mentioned "variation in line width", "migration resistance", and "resistivity value", only the case where "○" was obtained was evaluated as "○" in all cases. "○" (good), even if there is one "x" in each evaluation, it is evaluated as "x" (bad) in the comprehensive evaluation.

Table 2 shows the evaluations of the conductive pastes of Examples 1 to 5 and Comparative Examples 1 to 6 and circuit patterns (conductive patterns) produced using these conductive pastes.

【Table 2】

4. Inspection

According to Table 2, when the conductive pastes of Examples 1 to 5 and the conductive pastes of Comparative Examples 1 to 6 are compared, the conductive paste of the present invention is based on a silver-coated copper sheet and adds silver-coated silica powder to it. , and good results were obtained in the evaluation of any of the "variation in line width", "migration resistance" and "resistivity value" of the printed circuit pattern (conductive pattern), and it was found that the The conductive pattern is printed with little line width deviation and high precision, and the printed conductive pattern also has high electrical and thermal conductivity and high migration resistance, and has 30 Pa·s or more and A viscosity of 70 Pa·s or less provides excellent workability.

In particular, by comparing the conductive pastes of Examples 1 to 5 and the conductive pastes of Comparative Examples 1 to 3, it was found that the volume ratio of the silver-coated copper sheet to the silver-coated silica powder is preferably 99:1 to 15:1. In the range of 85, more preferably in the range of 99:1 to 20:80, in the printed circuit pattern, the deviation of the line width is small, and excellent migration resistance and conductivity can be obtained. As in the conductive pastes of Examples 1 to 4, when the volume ratio of the silver-coated copper flakes and the silver-coated silica powder is in the range of 99:1 to 90:10, more excellent migration resistance can be obtained.

In addition, with regard to the conductive pastes of Examples 1 to 5, by setting the blending amount of the silver-coated copper sheets to 10% by volume or more and 40% by volume or less with respect to the total nonvolatile content of the conductive paste, the printed circuit patterns can be found in the printed circuit patterns. , the variation in line width is small, excellent migration resistance and electrical conductivity can be obtained, and workability can be improved by having moderate viscosity and fluidity while keeping the resistivity value low. It was further found that, as in the conductive pastes of Examples 1 to 4, when the compounding amount of the silver-coated copper sheets was 30% by volume or more and 40% by volume or less with respect to the total nonvolatile content of the conductive paste, more excellent results were obtained. migration resistance.

In addition, it was found that in the conductive pastes of Examples 1 to 5, in order to realize workability and printability suitable for various printing methods such as screen printing, the total nonvolatile content of the resin binder relative to the conductive paste was It is effective to mix in a ratio of 30 volume % or more and 60 volume % or less.

Regarding the conductive pastes of Examples 1 to 5, it was found that when the volume average particle diameter (D ₅₀ ) of the silver-coated copper sheet is preferably 1.0 μm or more and 50 μm or less, and more preferably 2.0 μm or more and 20 μm or less, the printed In the circuit pattern of , there is little variation in the line width, and it is extremely easy to deal with thin lines when drawing the circuit pattern.

In addition, with regard to the conductive pastes of Examples 1 to 5, it was found that the volume average particle diameter (D ₅₀ ) of the silver-coated silica powder is preferably 0.050 μm or more and 50.0 μm or less, and more preferably 0.1 μm or more and 5.0 μm. Hereinafter, by achieving a high filling rate, the variation of the line width in the printed circuit pattern is also reduced while the resistivity value is kept low.

1 to 3 , it was found that, in a circuit pattern (conductive pattern) obtained by printing a plurality of lines with an interval of about 100 μm using the conductive paste of the present invention, since the variation in line width is small, adjacent ones The lines are not short-circuited (contacted) with each other, and furthermore, a circuit pattern excellent in the electrical conductivity of each line can be obtained.

Description of reference numerals

L...Printing Line

G... Gap (PET resin sheet)

S... short circuit portion (contact portion).

Claims (5)

1. A conductive paste, characterized in that, Contains silver-coated copper flakes and silver-coated silica powder. 2. The conductive paste according to claim 1, characterized in that, The blending ratio of the silver-coated copper sheet and the silver-coated silica powder is in the range of 99:1 to 15:85 by volume. 3. The conductive paste according to claim 1 or 2, characterized in that, The average particle diameter of the silver-coated copper sheet is 2.0 μm or more and 20.0 μm or less, and the average particle diameter of the silver-coated silica powder is 0.1 μm or more and 5.0 μm or less. 4 . The conductive paste according to claim 1 , wherein: 4 . The resin binder is further contained in a compounding amount of 30 vol % or more and 60 vol % or less with respect to the total nonvolatile content of the conductive paste. 5 . A conductive pattern formed using the conductive paste according to claim 1 .

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