JP2016219256A - Cu paste composition and thick film conductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Cu paste composition capable of improving sulfur resistance of a thick film electrode or a thick film wiring formed by applying same on a surface of a substrate and firing and capable of enhancing reliability of an electronic component or an electronic circuit.SOLUTION: There is provided a method for providing a Cu paste composition by mixing a Cu powder, a Ni powder and an organic vehicle with 0.7 to 20 pts.mass of the Ni powder and 5 to 40 pts.mass of the organic vehicle based on total 100 pts.mass of the Cu power and the Ni powder to obtain the Cu paste composition and mixing CuO powder of 1 to 15 pts.mass additionally.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a copper (Cu) paste composition for forming thick film conductors such as thick film electrodes and thick film wirings. Moreover, this invention relates to the thick film conductor formed with this Cu paste composition.

  In the field of chip resistors, hybrid ICs, resistor networks, touch panels and other electronic devices such as solar cells, and electronic circuits using these electronic components, conductive powder is uniformly used in organic solvents, etc. Generally, a thick film electrode or a thick film wiring is formed by applying a paste (conductive paste) dispersed on the surface of a glass substrate, an alumina substrate, a silicon substrate or the like and baking or thermosetting the paste. Has been done.

At this time, the conductive paste is applied by screen printing, gravure printing or drawing using a dispenser. As the conductive powder used in these conductive pastes, silver (Ag) powder having a low resistance value and excellent oxidation resistance is widely used. However, when a conductive paste containing Ag powder is used to form a thick film electrode or thick film wiring on the surface of the substrate, when a voltage is applied in an environment with a lot of moisture, the silver ionized between the electrodes There is a problem that a phenomenon (ion migration) occurs in which (Ag ⁺ ) moves and short-circuits. In addition, Ag powder has a high unit price, and it is difficult to reduce the manufacturing cost. Therefore, in recent years, as a conductive paste for forming thick film electrodes and thick film wiring, instead of Ag powder, copper (Cu) powder having a low resistance value and excellent migration properties has been used. The use of conventional conductive pastes has been studied and put into practical use.

  For example, in patent document 1 (Unexamined-Japanese-Patent No. 2004-039355), the electrically conductive paste which contains Cu powder and the glass powder which consists of crystallized glass and the difference of a softening point and crystallization start temperature is 100 degreeC or more. Has proposed. Such a conductive paste can form a conductive film having excellent sealing properties and good plating adhesion. However, since the conductive paste described in this document is mainly intended for connectivity with the external electrode of the multilayer ceramic capacitor, it is sufficient with respect to shrinkage, oxidation resistance and sulfidation resistance during firing. It is hard to say that it has been evaluated.

  On the other hand, in Patent Document 2 (Japanese Patent No. 3237497), although it is for through-hole conduction of a ceramic substrate, it is composed of Cu powder, nickel (Ni) powder, glass frit and organic vehicle, and Cu powder and Ni powder. Proposing a conductive paste in which the amount of Ni powder relative to the total amount is 1% by mass to 20% by mass, and the amount of glass frit relative to the total amount of Cu powder, Ni powder and glass frit is 1% by mass to 40% by mass. Yes. According to this document, it is said that by adding a certain amount of Ni powder to Cu powder, shrinkage during firing can be suppressed and peeling between the conductor and the through-hole side wall can be prevented.

  Patent Document 3 (Japanese Patent No. 4646362) discloses that the surface of an insulating substrate made of glass ceramics and / or the internal metallized wiring layer is Ni powder or nickel oxide (NiO) powder with respect to 100 parts by mass of Cu powder. Is formed by a conductive paste containing 1 part by mass to 10 parts by mass in terms of NiO and cupric oxide (CuO) powder at a rate of 0.1 part by mass to 3 parts by mass. In this conductive paste, CuO powder is added in order to suppress alloying of Cu and Ni during the firing process and to ensure the conductivity of the resulting metallized wiring layer.

By the way, due to the recent demand for miniaturization of electronic parts and electronic circuits, the demand for miniaturization of the thick film electrode and thick film wiring, in other words, the thick film electrode and the thickness that are narrower and the interval is narrower. There is an increasing demand for conductive pastes that enable the formation of film wiring. On the other hand, along with the miniaturization of such thick film electrodes or thick film wirings, it is caused by atmospheric hydrogen sulfide (H ₂ S) gas or sulfurous acid (H ₂ SO ₃ ) gas, which has not been a problem in the prior art. Sulfidation gradually increases the resistance value of thick film electrodes or thick film wiring, and eventually leads to disconnection, which is one of the factors that reduce the reliability of electronic components and electronic circuits. It has become one.

Japanese Patent Laid-Open No. 2004-039355 Japanese Patent No. 3237497 Japanese Patent No. 4646362

  The present invention is a Cu paste that can improve the reliability of electronic components and electronic circuits by improving the resistance to sulfidation of thick film electrodes and thick film wiring formed by applying and firing on the surface of a substrate. An object is to provide a composition and a thick film conductor.

  The Cu paste composition of the present invention is composed of Cu powder, Ni powder and an organic vehicle. The total amount of Cu powder and Ni powder is 100 parts by mass of Ni powder, and 0.7 to 20 parts by mass of Ni powder and organic vehicle. It contains 5 to 40 parts by mass.

  When the Cu paste composition is baked at 550 ° C. to 750 ° C. in a non-oxidizing atmosphere to form a thick film conductor having a thickness of 10 μm, the sheet resistance of the thick film conductor is 50 mΩ / □ or less. be able to.

The Cu paste composition preferably further contains 1 to 15 parts by mass of Cu ₂ O powder with respect to 100 parts by mass in total of the Cu powder and Ni powder.

By adding the Cu ₂ O powder, the firing temperature of the Cu paste composition can be lowered. That is, the Cu paste composition containing the Cu ₂ O powder is fired at 500 ° C. to 750 ° C. in a non-oxidizing atmosphere to form a thick film conductor having a thickness of 10 μm. The resistance value can be 50 mΩ / □ or less.

The average particle size of the Cu ₂ O powder is preferably 0.5 μm to 5 μm.

  Moreover, the Cu paste composition of this invention may further contain 0.5 mass part-5 mass parts of glass powder with respect to a total of 100 mass parts of the said Cu powder and Ni powder.

  The average particle diameter of the Cu powder and Ni powder is preferably 0.2 μm to 0.7 μm.

In the Cu paste composition of the present invention, a thick film conductor was formed between a pair of Au electrodes, the sheet resistance in the initial state of the thick film conductor was R _s0 , and the thick film conductor was held at 80 ° C. the area resistance value after immersion for 6 hours in cutting oil containing 0.3 wt% of sulfur in the case of the R _s6, the resistance change ratio defined by the ratio R _s6 / R _s0 of R _s6 for R _s0 20 It can be as follows.

  The thick film conductor of the present invention can be formed by the above-described Cu paste composition.

  According to the Cu paste composition and the thick film conductor of the present invention, an increase in resistance value due to sulfidation of a thick film electrode or a thick film wiring formed on the surface of the substrate can be suppressed over a long period of time. It becomes possible to improve the reliability of components and electronic circuits. Moreover, the Cu paste composition of the present invention can be easily mass-produced industrially. For this reason, the industrial significance of the present invention is extremely large.

FIG. 1 is a diagram showing the sulfidation resistance of the samples obtained in Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-3. FIG. 2 is a diagram showing the sulfidation resistance of the samples obtained in Examples 2-1 to 2-13 and Comparative Examples 2-1 to 2-3.

  In view of the above-mentioned problems, the present inventors have added various elements to a Cu paste composition for forming a thick film conductor such as a thick film electrode and a thick film wiring, and have improved the area resistance value and the sulfidation resistance. The test to be evaluated was repeated. As a result, when a predetermined amount of Ni powder is added to the Cu paste composition, Cu and Ni are alloyed when the Cu paste composition is fired, and the sulfidation resistance of the thick film conductor is dramatically improved. The knowledge that it can be obtained. The present invention has been completed based on this finding.

1. Constituent Components Hereinafter, the Cu paste composition of the present invention will be described in detail for each constituent component. In the present invention, Cu powder and Ni powder, which are cheaper than Ag powder, are used as the conductive powder, so that the production cost can be greatly reduced. Moreover, the manufacturing method of the Cu paste composition of the present invention is not limited as long as the following constituent components can be uniformly mixed. For example, it can manufacture by mixing and stirring by well-known means, such as a 3 roll mill and a mixer.

(1) Cu powder and Ni powder The Cu paste composition of the present invention is characterized by adding a certain amount of Ni powder to Cu powder. Thereby, the sulfidation resistance of the thick film conductor obtained by applying the Cu paste composition onto the substrate and baking it can be improved.

[Content of Ni powder]
The content of the Ni powder is 0.7 parts by mass to 20 parts by mass, preferably 0.7 parts by mass to 12 parts by mass, more preferably 1 part by mass to 100 parts by mass of the total of the Cu powder and the Ni powder. 3 parts by mass. When the Ni content is less than 0.7 parts by mass, the sulfidation resistance of the thick film conductor cannot be sufficiently improved. On the other hand, if the Ni content exceeds 20 parts by mass, the area resistance value of the thick film conductor becomes high and cannot be used as an electrode material or a wiring material.

[Average particle diameter of Cu powder and Ni powder]
Since Ni has a higher melting point and slower diffusion rate than Cu, the addition of Ni powder inhibits the sintering of the Cu paste composition, and if it is not fired at a high temperature, Cu and Ni are appropriately alloyed. Can not do. On the other hand, it is generally known that sintering can be promoted by making the sintered material fine. For this reason, in the Cu paste composition of the present invention, the average particle size of Cu powder and Ni powder is preferably 0.2 μm to 0.7 μm, more preferably 0.2 μm to 0.5 μm, More preferably, the thickness is 0.3 μm to 0.5 μm. If the average particle diameter of Cu powder and Ni powder is in such a range, sintering of Cu powder and Ni powder can be promoted, and even when the firing temperature is relatively low, Cu and It becomes possible to alloy with Ni appropriately.

  On the other hand, when the average particle size of the Cu powder and Ni powder is less than 0.2 μm, it becomes possible to fire at a lower temperature, but the oxygen content in the Cu paste composition increases, and the Cu powder and Ni powder increase. The alloying of the powder will be hindered. On the other hand, if the average particle size of the Cu powder and Ni powder exceeds 0.7 μm, the sintering may be inhibited, and the above-described sintering acceleration effect may not be obtained.

In addition, in this invention, an average particle diameter means the volume reference | standard average particle diameter (MV) calculated | required by the laser diffraction scattering method, and can measure it with a laser diffraction scattering type particle size distribution measuring apparatus. The same applies to cuprous oxide (Cu ₂ O) powder and glass powder described later.

(2) Organic vehicle Although an organic vehicle is required at the time of application | coating of Cu paste composition, it burns down at the time of baking and does not contribute to the improvement of the sulfidation resistance of a thick film conductor. For this reason, in the Cu paste composition of this invention, the kind of organic vehicle is not restrict | limited, A well-known thing can be used. Typical organic vehicles include those obtained by dissolving ethyl cellulose, acrylic resin or methacrylic resin in a solvent such as terpineol or higher alcohol.

  The content of the organic vehicle is 5 parts by mass to 40 parts by mass, preferably 10 parts by mass to 35 parts by mass, more preferably 20 parts by mass to 30 parts by mass with respect to 100 parts by mass of the total of Cu powder and Ni powder. To do. When the content of the organic vehicle is less than 5 parts by mass, the viscosity of the Cu paste composition becomes high and a uniform coating film cannot be formed. On the other hand, if the content of the organic vehicle exceeds 40 parts by mass, not only the fired thick film electrode or thick film wiring becomes too thin, but also the organic vehicle cannot be completely burned off during firing, Sintering of Ni powder will be inhibited.

(3) Glass powder In the case where a thick film conductor is directly formed on a substrate using the Cu paste composition of the present invention, the above-described configuration is used from the viewpoint of improving the adhesion between the Cu paste composition and the substrate. You may add glass powder to a component further. However, when wire bonding or soldering is performed, it may be better not to add glass powder. For this reason, the addition of the glass powder needs to be appropriately selected according to the use and purpose of the Cu paste composition.

  The glass powder added to the Cu paste composition is not particularly limited as long as the softening point is lower than the firing temperature of the Cu paste composition, but from the viewpoint of environmental protection, lead (Pb) and Those containing no toxic substances such as cadmium (Cd) are preferred.

  When glass powder is added to the Cu paste composition, the content is preferably 0.5 parts by mass to 5 parts by mass with respect to 100 parts by mass in total of Cu powder and Ni powder. More preferably, it is 3 parts by mass. When the content of the glass powder is less than 0.5 parts by mass, the adhesion between the thick film conductor and the substrate may not be sufficiently improved after firing. On the other hand, when the content of the glass powder exceeds 5 parts by mass, not only the resistance value of the thick film conductor becomes high, but also the solder wettability and plating adhesion of the thick film conductor may be lowered.

  The average particle size of the glass powder is not particularly limited, but is preferably 1 μm to 10 μm, more preferably 3 μm to 5 μm from the viewpoint of uniform mixing with Cu powder, Ni powder, and the like.

(4) Cu ₂ O powder When Ni powder is added to the Cu paste composition as described above, the sintering may be inhibited. Further, when a resin that is difficult to be burned down by firing in a non-oxidizing atmosphere, such as ethyl cellulose, is used as the organic vehicle, depending on the amount of addition, the sintering of the Cu paste composition may be inhibited.

As a result of repeated studies on this point, the present inventors have determined that a certain amount of cuprous oxide (Cu) is added to the Cu paste composition in which the above-described Cu powder, Ni powder and organic vehicle or glass powder in addition to these are added. _{It has been found} that by further adding ₂ O) powder, the sinterability is improved and Cu and Ni can be appropriately alloyed even when fired at a lower temperature.

The reason why such a sinterability improvement effect can be obtained by adding Cu ₂ O powder is unknown at present, but the present inventors have used cupric oxide (CuO) instead of Cu ₂ O powder. A Cu paste composition was prepared in the same manner except that the powder was added, and the experiment for measuring the firing temperature was repeated. As a result, this Cu paste composition did not provide a sufficient sinterability improvement effect. It was confirmed. That is, although the above-mentioned Japanese Patent No. 464362 describes that a copper oxide powder is added to a Cu paste composition, the copper oxide powder in this document is a CuO powder. Thus, it is considered that the effect of improving the sinterability is hardly obtained. In this document, CuO powder is added in order to suppress alloying of Cu and Ni. Therefore, it can be said that the Cu paste composition described in the present invention and Japanese Patent No. 464362 is a technology that is greatly different in these respects.

Since Cu ₂ O powder in the Cu paste composition of the present invention is decomposed during firing, it is present in the thick film conductor in an alloyed state with Cu powder and Ni powder after firing. it is conceivable that.

[Cu ₂ O powder content]
When adding Cu ₂ O powder, the content thereof, per 100 parts by weight of Cu powder and Ni powder, 15 parts by weight 1 part by weight, preferably 5 parts by mass to 10 parts by mass. If the range content, such as this of Cu ₂ O powder, it is possible to obtain a sufficient sintering property improving effect of the Cu paste composition. Specifically, even when the Cu paste composition is fired at 500 ° C., the Cu powder and the Ni powder can be sufficiently sintered, and Cu and Ni can be appropriately alloyed.

On the other hand, when the content of the Cu ₂ O powder is less than 1 part by mass, the effect of improving the sinterability cannot be sufficiently obtained. On the other hand, if the content of Cu ₂ O powder exceeds 15 parts by mass, unreacted Cu ₂ O powder may remain, which may inhibit sintering or reduce the adhesion of solder and plating. is there.

[Average particle diameter of Cu ₂ O powder]
The average particle diameter of the Cu ₂ O powder is preferably 0.5 μm to 5 μm, preferably 1 μm to 2 μm from the viewpoint of uniformly mixing with Cu powder, Ni powder, and the like and efficiently obtaining a sinterability improvement effect. More preferably.

(5) Other additive components In the Cu paste composition of the present invention, In, Sn, Zn, and the like can be added from the viewpoint of lowering the firing temperature in addition to the above-described components. It is also possible to add a dispersant or a viscosity modifier. However, it is necessary to regulate the amount of addition of these other additive components within a range that does not hinder the effects of the addition of the Ni powder or Cu ₂ O powder described above.

2. Characteristics of Cu Paste Composition (1) Firing Temperature The temperature (firing temperature) at which the Cu paste composition of the present invention is applied and fired on the surface of the substrate is 550 when Cu ₂ O powder is not included. ℃ ～ 750 ℃ On the other hand, when Cu ₂ O powder is included, the temperature is set to 500 ° C. to 750 ° C. By setting the firing temperature of the Cu paste composition in such a range, it becomes possible to form a thick film conductor even on a substrate having low high-temperature durability. Moreover, since it becomes possible to form a multilayer wiring, the application range of Cu paste composition can be expanded.

On the other hand, when the firing temperature of the Cu paste composition containing no Cu ₂ O powder is less than 550 ° C., or when the firing temperature of the Cu paste composition containing Cu ₂ O powder is less than 500 ° C., Cu and Ni cannot be appropriately alloyed. On the other hand, none of the Cu paste compositions can obtain a further effect even if the firing temperature exceeds 750 ° C., and also causes an increase in production cost.

(2) Area Resistance Value When the Cu paste composition of the present invention is applied onto a substrate and baked at the baking temperature described above to form a thick film conductor having a thickness of 10 μm, the area resistance value R _s Is preferably 50 mΩ / □ or less, more preferably 20 mΩ / □ or less, and even more preferably 10 mΩ / □ or less. Here, the sheet resistance value R _s is also called sheet resistance, and it is known that the resistance value R has the following relationship.
R = ρ × L / A = ρ × L / (W × t) = ρ / t × L / W = R _s × L / W
ρ: resistivity,
A: Cross-sectional area of sample L: Length of sample W: Width of sample t: Sample thickness

  In addition, the area resistance value of the thick film conductor mentioned above is so preferable that it is small, and the minimum is not restrict | limited. The sheet resistance value can be measured by a known means.

(3) Sulfide resistance Since the thick film conductor obtained by the Cu paste composition of the present invention is excellent in sulfidation resistance, the sheet resistance value can be maintained within the above-described range for a long period of time. The sulfidation resistance of such a thick film conductor can be evaluated by a sulfidation test described below.

First, a pair of Au electrodes is formed by printing an Au paste composition on a substrate so that the distance between the electrodes is 50 mm and baking the Au paste composition. Subsequently, a Cu paste composition is applied between the Au electrodes and fired at the firing temperature described above in an inert atmosphere to form a thick film conductor having a width of 0.5 mm and a thickness of 10 μm to 13 μm. In this state (initial state), the resistance value is measured at five or more positions between the Au electrodes, and the area resistance value R _s0 of the thick film conductor is calculated from the average value and thickness of the resistance value of the thick film conductor. To do. Next, the thick film conductor is immersed in the cutting oil containing 0.3% by mass of sulfur (S) kept at 80 ° C. together with the substrate. After the elapse of time t, the thick film conductor is pulled up and the _sheet resistance value _Rst of the thick film conductor is calculated in the same manner. By calculating the resistance change rate defined by the ratio R _st / R _s0 of R _{st to} R _s0 from the area resistance values R _s0 and R _st thus obtained, the resistance to sulfidation of the thick film conductor can be improved. Can be evaluated. In this sulfidation test, the Au electrode is used as the electrode. Since Au is not corroded by sulfur (S), the influence of the electrode is ignored when measuring the sheet resistance of the thick film conductor after the sulfidation test. Because it can be done.

In particular, in the case where a thick film conductor is formed using the Cu paste composition of the present invention, the cutting oil containing 0.3% by mass of sulfur held at 80 ° C. with respect to the _sheet resistance value R _{s0 in the} initial state is 6 the resistance change ratio defined by the ratio R _s6 / R _s0 of the area resistance value after immersion time R _s6, preferably 20 or less, more preferably 10 or less, more preferably, to 1.5 or less .

3. Thick film conductor The thick film conductor of this invention can be formed with the Cu paste composition mentioned above. As described above, this thick film conductor has excellent sulfidation resistance and is not corroded by hydrogen sulfide gas or sulfurous acid gas in the atmosphere. Therefore, in response to miniaturization of electronic components and electronic circuits, even when the thick film electrode or thick film wiring made of this thick film conductor is miniaturized, it is effective to effectively disconnect or increase the resistance value. Can be suppressed. For this reason, it becomes possible by using the thick film conductor of this invention to improve the reliability of an electronic component or an electronic circuit dramatically.

  Specific examples to which the present invention is applied will be described below, but the present invention is not limited to these examples.

(Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-3)
[Preparation of Cu paste composition]
Components of Cu paste composition include Cu powder and Ni powder having average particle diameters of 0.2 μm and 0.5 μm, SiO ₂ —B ₂ O ₃ —ZnO glass powder having an average particle diameter of 3 μm and a softening point of 450 ° C. In addition, an organic vehicle in which an acrylic resin was dissolved in terpineol was prepared. In addition, the average particle diameter of these powders is measured with a laser diffraction scattering type particle size distribution measuring apparatus (Nikkiso Co., Ltd., Microtrack). Examples 1-1 to 1-9 and Comparative Example 1 were prepared by blending these components so as to have a composition ratio shown in Table 1, kneading using a three-roll mill, and sufficiently dispersing each component. Cu paste compositions of −1 to 1-3 were obtained.

[Evaluation of sheet resistance and sulfidation resistance]
A film after firing using a pattern having a width W of 0.5 mm and an electrode spacing L of 50 mm on the surface of a 96% alumina substrate on which an Au electrode has been formed by printing and firing an Au paste composition in advance. The Cu paste compositions of Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-3 were printed so that the thickness t was 10 μm to 13 μm, and baked at 750 ° C. for 1 hour in an N ₂ atmosphere. As a result, samples for the sulfidation test were prepared.

A resistance value measuring probe of a digital multimeter (manufactured by Advantest Co., Ltd.) was contacted at five locations between the Au electrodes of these samples, and the resistance value R [t] of the thick film conductor was measured. Subsequently, the resistance value R [t] is converted into an area resistance value R _s [t] (= R (t) × W / L) to obtain an average value R _s0 [t]. The sheet resistance value R _s0 (= R _s [t] × t / 10) when the thickness of the conductor is 10 μm was calculated.

Next, these samples were immersed in a cutting oil containing 0.3% by mass of S held at 80 ° C. for acceleration evaluation, after 1 hour, 2 hours, 3 hours and 6 hours. The sheet resistance values R _s1 , R _s2 , R _S3 and R _s6 were calculated in the same manner. These results are shown in Table 2 and FIG.

(Examples 2-1 to 2-13 and Comparative Examples 2-1 to 2-3)
[Preparation of Cu paste composition]
Components of Cu paste composition include Cu powder and Ni powder having an average particle size of 0.2 μm and 0.3 μm, SiO ₂ —B ₂ O ₃ —ZnO glass powder having an average particle size of 3 μm and a softening point of 450 ° C. Cu ₂ O powder having an average particle diameter of 0.5 μm and 1.5 μm, and an organic vehicle in which ethyl cellulose was dissolved in terpineol were prepared. Examples 2-1 to 2-13 and Comparative Example 2 were prepared by blending these components so as to have the composition ratio shown in Table 3, kneading using a three-roll mill, and sufficiently dispersing each component. Cu paste compositions of −1 to 2-3 were obtained.

[Evaluation of sheet resistance and sulfidation resistance]
Using a pattern having a width of 0.5 mm and an electrode interval of 50 mm on the surface of a 96% alumina substrate on which an Au electrode was formed by printing and firing an Au paste in advance, the film thickness after firing was 10 μm to The Cu paste compositions of Examples 2-1 to 2-13 and Comparative Examples 2-1 to 2-3 were printed so as to be 13 μm, and baked at 550 ° C. for 1 hour in an N ₂ atmosphere, thereby sulfiding. Test samples were prepared.

The area resistance values R _s0 , R _s1 , R _s2 , R _s3 and R _s6 of these samples were calculated in the same manner as in Examples 1 to 9 and Comparative Examples 1 to 3. These results are shown in Table 4 and FIG.

(Evaluation)
From Tables 1-4, FIG. 1 and FIG. 2, the thick film conductor obtained by apply | coating and baking the Cu paste composition of Examples 1-1 to 1-9 and Examples 2-1 to 2-13, In both cases, the area resistance value R _s0 in the initial state is 50 mΩ / □ or less, and the resistance change rate R _s6 / R _s0 is 20 or less, and it is confirmed that the film has excellent sulfidation resistance.

When the thick film conductor obtained by applying and printing the Cu paste composition of Example 2-12 was analyzed by X-ray diffraction, the diffraction peaks of Cu and Ni were observed as in the other examples. Only the diffraction peak of the Cu—Ni alloy was observed. Therefore, when Cu ₂ O powder is added, it is confirmed that Cu and Ni can be appropriately alloyed even when the firing temperature is set to about 500 ° C., and the sulfidation resistance can be improved. It was.

Claims (9)

  It consists of Cu powder, Ni powder and organic vehicle, and contains 0.7 to 20 parts by mass of Ni powder and 5 to 40 parts by mass of organic vehicle with respect to a total of 100 parts by mass of Cu powder and Ni powder. Cu paste composition.   2. The area resistance value of the thick film conductor is 50 mΩ / □ or less when a thick film conductor having a thickness of 10 μm is formed by firing at 550 ° C. to 750 ° C. in a non-oxidizing atmosphere. Cu paste composition. The Cu paste composition according to claim 1, further comprising 1 to 15 parts by mass of Cu ₂ O powder with respect to 100 parts by mass in total of the Cu powder and Ni powder.   4. The area resistance value of the thick film conductor is 50 mΩ / □ or less when the thick film conductor having a thickness of 10 μm is formed by firing at 500 ° C. to 750 ° C. in a non-oxidizing atmosphere. Cu paste composition. The average particle size of the Cu ₂ O powder is 0.5 m to 5 m, according to claim 3 or Cu paste composition according to 4.   The Cu paste composition according to claim 1 or 3, further comprising 0.5 to 5 parts by mass of a glass powder with respect to 100 parts by mass in total of the Cu powder and Ni powder.   The Cu paste composition according to claim 1, 3 or 6, wherein the Cu powder and the Ni powder have an average particle size of 0.2 μm to 0.7 μm. A thick film conductor is formed between a pair of Au electrodes, the sheet resistance in the initial state of the thick film conductor is R _s0 , and the thick film conductor is kept at 80 ° C. and contains 0.3% by mass of sulfur. in the case of a 6-hour immersion area resistance value after the set to R _s6, the resistance change ratio defined by the ratio R _s6 / R _s0 of R _s6 for R _s0 is 20 or less, any of the preceding claims Cu paste composition according to any one of the above. A thick film conductor formed of the Cu paste composition according to claim 1.

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