WO2018216509A1

WO2018216509A1 - Composition for forming conductor, conductor, production method therefor, and chip resistor

Info

Publication number: WO2018216509A1
Application number: PCT/JP2018/018367
Authority: WO
Inventors: 剛川島; 慎吾粟ケ窪
Original assignee: 住友金属鉱山株式会社
Priority date: 2017-05-26
Filing date: 2018-05-11
Publication date: 2018-11-29
Also published as: KR102543291B1; CN110663088B; CN110663088A; JP6801586B2; JP2018200793A; TWI783999B; TW201901705A; KR20200016847A

Abstract

Provided are: a composition for forming a conductor, the composition requiring, during a baking step that uses a belt furnace, no jig to prevent cementing from taking place between a dried film and a belt, etc., and which enables forming of a conductor pattern with fine lines; and a production method therefor. Disclosed is a composition for forming a conductor, the composition comprising a conductive powder, an inorganic powder substance other than said conductive powder, glass frits, and an organic vehicle, wherein the inorganic powder substance has an average particle diameter of 0.3-5.0 μm as determined by SEM measurement and a sintering initiation temperature higher than that of the conductive powder, and is included in an amount of 10-45 parts by mass with respect to 100 parts by mass of the conductive powder.

Description

Conductor forming composition, conductor and method for producing the same, and chip resistor

The present invention relates to a conductor-forming composition, a conductor and a method for producing the same, and a chip resistor.

Conductors for forming electrodes and circuits such as electronic parts are formed by using a conductor-forming composition formed by dispersing conductive powder having high conductivity in an organic vehicle together with glass frit, for example. Is done. For example, the conductor is formed by applying the conductor-forming composition onto a ceramic substrate such as an alumina substrate in a required shape by a screen printing method or the like, drying at 120 ° C. to 150 ° C., and then at 600 ° C. to 900 ° C. It is formed by firing.

Conventionally, when a conductor is formed on the outer surface of a chip component such as a multilayer ceramic capacitor (hereinafter also referred to as “MLCC”), the conductor-forming composition is applied to the outer surface of the chip component, dried, and dried. In the process of firing together with the chip parts, there is a problem that adjacent chip parts are joined together or are joined to a shelf board such as a ceramic on which the chip parts are placed. In order to prevent these joining, methods such as applying powder such as alumina have been made in the subsequent process of applying the conductor forming composition, but a process of removing the powder such as alumina after firing is necessary. , It took time and effort. In view of this, several proposals have been made in order to prevent bonding between the external electrode of the multilayer ceramic capacitor and another member.

For example, Patent Document 1 describes that metal powder having various types of particles, for example, two kinds of large and small spherical powders and scale-like metal powders, etc. are used for the conductive paste. Patent Document 2 describes a conductive paste containing a metal powder and glass frit and containing 1 to 10 wt% of a metal additive having a melting point higher than that of the metal powder. These conductive pastes suppress the sintering of the metal powder during firing, the metal component does not shrink closely, and a gap is formed between the metal components, so that the glass component that causes bonding is a conductor layer. It is described that it can be prevented from oozing out on the surface of the glass.

In Patent Document 3, it is described that an inorganic powder having an average particle size of 0.1 mm or less is used. A method is described in which the inorganic powder is exposed to the surface of the conductor layer, thereby preventing seizure between MLCC chips or a ceramic mortar in which the MLCC chip is installed in the MLCC firing step. Patent Document 4 describes a conductive paste in which the composition of the glass powder is limited in order to control the fluidity of the glass and prevent it from seeping out onto the surface of the conductor layer.

The above problems also occur when manufacturing chip resistors. The chip resistor includes a pair of conductors (surface electrode and back electrode) provided on the front and back surfaces of the substrate, a resistor provided between the pair of surface electrodes, and an insulating protective layer covering the resistor. And a pair of end surface electrodes provided on the end surface of the substrate and conducting the front surface electrode and the back surface electrode. The back electrode formed on the chip resistor is for electrically bonding the chip resistor and the circuit board when the chip resistor is mounted on the circuit board.

The chip resistor is manufactured by the following method, for example. First, prepare a substrate (slit substrate) with slits in a desired dimension according to the chip size in advance, and print and dry the conductor-forming composition so as to straddle the slit on this substrate, By firing, a plurality of pairs of conductors (surface electrode and back electrode) are formed on the front surface and the back surface of the substrate, respectively. Next, after forming a resistor on the surface of the substrate so that each pair of surface electrodes is disposed at both ends thereof, a glass layer called a precoat is formed on the resistor, and a protective layer is further formed thereon. For example, a resin layer is formed. Next, the substrate is divided into strips along the slits, end electrodes are formed and plated, and then the strip-like substrate is further divided to obtain chip resistors.

Conductors (front electrode and back electrode) are formed into a required shape by, for example, screen-printing or the like on a substrate with a conductive composition in which an electrically conductive powder having high electrical conductivity and glass frit are dispersed in an organic vehicle. It is formed by coating and drying at about 120 ° C. to 150 ° C. and then baking at about 600 ° C. to 900 ° C. Also, in the case where conductors (surface electrode and back electrode) are formed on both sides of a substrate, conventionally, a conductor forming composition is printed on one surface of the substrate, and then dried and baked to conduct the conductor (eg, back electrode). After that, printing, drying and baking are similarly performed on the other surface of the substrate to form a conductor (for example, a surface electrode).

In recent years, from the request for cost reduction and energy saving, the process from drying to baking has been simplified. For example, in the case of a chip resistor, in the process of forming conductors (front and back electrodes), the conductor-forming composition is printed on one side of the substrate and dried to form a dry film (for example, a back dry film). Then, before firing, the conductor-forming composition is printed on the other surface of the substrate and dried to form a dry film (for example, a surface dry film). And a baking process can be skipped once by baking the dry film of both surfaces of a board | substrate simultaneously. However, in such a production method, for example, when the dried film is baked in a belt furnace, the dried film is always present on the surface facing the belt, and the dried film formed on the surface facing the belt is The belt portion of the belt furnace may be touched, the belt and the conductor may be joined, the conductor pattern may come off, or the conductor may adhere to the belt, making the belt furnace unusable. In order to prevent such bonding between the belt and the conductor, when firing the dry film formed on both surfaces of the substrate, a jig is required to prevent the dry film from touching other members.

On the other hand, in recent years, miniaturization and high density of electrode patterns have been progressing due to demands for downsizing and large capacity of electronic components, and for conductor formation capable of forming electrode patterns with finer line widths. There is a need for a composition.

JP-A-8-306580 Japanese Patent Laid-Open No. 10-12481 JP-A-9-129480 JP 2001-297628 A

Incidentally, the techniques described in Patent Documents 1 to 4 have the following problems when forming the conductors of the resistor (front electrode and back electrode). That is, in the conductive paste described in Patent Document 1 and Patent Document 2, a gap is formed between the metal components when the conductor is formed, so that the conductive powder is not sufficiently sintered, and the electrical resistivity of the conductor is low. It cannot easily be applied to electrodes of electronic parts such as resistors that are likely to be high and require a low-resistance conductor. Also, with these conductive pastes, the conductor is likely to become brittle, the bonding strength between components via the conductor is likely to be insufficient, and the surface of the conductor is likely to be sparse, so electrolytic plating is performed on the conductor. In such a case, there is a problem that the acidic plating solution easily enters the inside, and the glass component dissolves into the plating solution and the strength is easily lowered.

Further, in the conductive paste of Patent Document 3, inorganic particles having an average particle diameter of 0.05 mm to 0.2 mm are used in the examples. A conductive paste containing such large particles is used as a chip resistor. When printed on the slit substrate for manufacturing, the inorganic particles ooze out between the slits, or when the slit substrate is divided, the inorganic particles fall off, the electrodes are perforated, and the dropped inorganic particles are contaminated. As a result, defects may occur in the manufacturing process. Also, manufacturing an electronic component so that inorganic powder that does not have conductivity is usually exposed on the surface causes unsatisfactory connection when mounted on a circuit board, resulting in an increase in the defect rate. it is conceivable that.

Furthermore, in the conductive paste described in Patent Document 4, an alkali metal oxide is contained in the glass powder. For example, when combining a conductor and another member such as a resistor in a chip resistor, the alkali component is It may easily enter other members and may affect the characteristics of the members. Further, as described in the composition of the glass powder used in the conductive paste, it is difficult to obtain adhesion strength to the base material when the conductor layer is formed on the ceramic as described in that it is difficult to wet the ceramic body.

On the other hand, when firing for forming the conductors of the resistor (front electrode and back electrode) using a conventional conductor forming composition in a belt furnace, other members such as a dry film and a belt are used. Therefore, it is necessary to provide a process for preventing the contact with a jig, which is an obstacle to simplification of the process.

In view of the above circumstances, for example, in the firing process using a belt furnace, the present invention does not cause the joining of the dry film and other members such as a belt without using a jig, and the conductor pattern is made into a fine line. An object of the present invention is to provide a conductor-forming composition and a method for producing the same.

According to a first aspect of the present invention, there is provided a conductor-forming composition comprising a conductive powder, an inorganic powder other than the conductive powder, a glass frit, and an organic vehicle, wherein the inorganic powder is used for SEM measurement. The average particle size is 0.3 μm or more and 5.0 μm or less, has a sintering start temperature higher than that of the conductive powder, and includes 10 parts by mass or more and 45 parts by mass or less with respect to 100 parts by mass of the conductive powder. A conductor-forming composition is provided.

The inorganic powder preferably contains at least one of a metal powder, a metal oxide powder, and a metal powder having an oxide film. The inorganic powder preferably contains at least one of copper powder, copper oxide powder, and copper powder having an oxide film. Moreover, it is preferable that an organic vehicle contains binder resin and a solvent, and binder resin is contained 1 mass% or more and 10 mass% or less with respect to the composition for conductor formation. The conductive powder preferably contains at least one of Au, Ag, Pd and Pt. Further, when the conductor-forming composition is placed on a belt using a belt furnace and fired, the inorganic powder is present on the surface more than the inside of the conductor, whereby the conductive powder belt. It is preferable that seizure to the member can be prevented. Further, it is preferably used for forming at least one of a front electrode and a back electrode of the chip resistor.

In the second aspect of the present invention, the conductor-forming composition is applied to at least one surface of the substrate, and the substrate coated with the conductor-forming composition is dried to be contained in the conductor-forming composition. Removing at least a portion of the solvent, forming a dry film on the substrate, firing the substrate on which the dry film is formed, sintering the conductive powder contained in the conductor-forming composition, and inorganic powder Forming a conductor that is present more on the surface opposite to the surface in contact with the substrate than on the inside.

In the method for producing a conductor, the conductor-forming composition contains a metal powder as an inorganic powder, and the metal powder reacts with oxygen in the atmosphere during firing to have a metal oxide powder or an oxide film. Can be formed. The metal powder is preferably copper powder.

In the third aspect of the present invention, the conductor is formed on the substrate using the above-mentioned conductor-forming composition, and the inorganic powder is disposed in the conductor so as to be biased toward the surface opposite to the surface in contact with the substrate. A conductor is provided.

In the fourth aspect of the present invention, there is provided an electronic component having a conductor formed using the above-described conductor-forming composition.

In a fifth aspect of the present invention, there is provided a chip resistor that includes at least a substrate, a conductor, and a resistor, and the conductor is formed using the above-described conductor-forming composition.

The conductor-forming composition of the present invention can suppress the phenomenon that the dried film obtained in the conductor production process is bonded to other members such as a belt of a belt furnace in the firing process. Moreover, the conductor pattern obtained using the conductor forming composition of the present invention can be made into a fine line. In addition, the conductor manufacturing method of the present invention can easily and efficiently produce a fine line conductor pattern. In addition, even when the conductor obtained using the conductor-forming composition is obtained by placing on a belt of a belt furnace and firing, the bonding of the conductor component to the belt is suppressed and low. It can have a resistance value.

FIG. 1A is a cross-sectional view schematically showing an example of a conductor formed on a substrate portion, and FIG. 1B is an enlarged cross-sectional view of a part of the conductor. FIG. 2A is a cross-sectional view schematically showing an example of a state in which the substrate portion on which the conductor is formed is placed on the belt of the belt furnace, and FIG. 2B is an enlarged view of a part of the conductor. FIG. 2C is a sectional view schematically showing a dry film (or conductor). FIG. 3 is a flowchart showing an example of a conductor manufacturing method. FIG. 4 is a schematic diagram illustrating an example of a chip resistor. FIG. 5 is a SEM photograph showing a contact portion of the conductor of Example 1 with the belt. FIG. 6 is an SEM photograph showing a contact portion of the conductor of Comparative Example 1 with the belt.

Hereinafter, an example of each embodiment of the present invention will be described in detail with reference to FIGS. In the drawings, in order to make each configuration easy to understand, some parts are emphasized or some parts are simplified, and actual structures, shapes, scales, and the like may be different.

The conductor-forming composition of the present embodiment includes a conductive powder, an inorganic powder other than the conductive powder, a glass frit, and an organic vehicle. By including the inorganic powder, the conductor-forming composition can suppress bonding of the obtained conductor to other members. Hereinafter, with reference to FIGS. 1 and 2, a dry film obtained using the conductor-forming composition of the present embodiment and the formed conductor will be described.

FIG. 1A is a schematic diagram showing an example of a conductor of the present embodiment formed on a substrate part. The conductor 10 is formed in layers on one or both surfaces of the substrate unit 20. The conductor 10 is formed by applying a conductor-forming composition to the substrate unit 20, drying it, and firing it. The board | substrate part 20 is a board | substrate part (area | region) which forms one chip component among slit substrates, for example. The substrate unit 20 is not particularly limited, and a known substrate can be used. For example, an alumina substrate containing alumina as a main component can be used. In addition, the conductor 10 may be formed on one surface (front surface or back surface) of the board | substrate part 20, and may be formed on both surfaces (front surface and back surface).

FIG. 1 (B) is an enlarged view showing a portion of the conductor 10 surrounded by a broken line in FIG. 1 (A). As shown in FIG. 1B, the conductor 10 includes an inorganic powder 1 and a conductor portion 2 formed by sintering conductive powder. The conductor part 2 contains the metal derived from electroconductive powder, and the glass derived from a glass frit. In addition, the component originating in the organic vehicle contained in the composition for conductor formation is removed by the process of drying and baking.

The inorganic powder 1 is disposed on the surface of the conductor 10, at least on the surface opposite to the surface where the conductor 10 and the substrate portion 20 are in contact with each other, so as to be present more than the inside. Since many inorganic powders 1 are arranged so as to be biased toward the surface of the conductor 10, the contact area between the metal component contained in the conductor 10 and another member (for example, a belt member of a belt furnace) in contact with the conductor 10 is reduced. It is possible to suppress the bonding between the other member and the metal component. When the conductor 10 is used as a conductor of a resistor (at least one of a front electrode and a back electrode), the thickness of the conductor 10 can be 2 μm or more and 10 μm or less, and preferably 3 μm or more and 8 μm or less. The thickness of the conductor can be measured with a stylus type surface roughness meter.

FIG. 2 (A) to FIG. 2 (C) are diagrams schematically showing a dry film or a conductor. The dry film 11 can be obtained by applying the conductor-forming composition of the present embodiment on the substrate portion 20 and drying it. The obtained dry film 11 is placed on, for example, a belt member 25 of a belt furnace as shown in FIG. The belt member 25 contacts at least a part of the surface of the dry film 11 formed on the substrate unit 20. FIG. 2B is an enlarged schematic view showing a contact portion between the dry film 11 and the belt member 25. As shown in FIG. 2B, the inorganic powder 1 is dispersed almost uniformly in the dry film 11.

FIG. 2C is a schematic diagram showing the dry film 11 or the layered conductor 10 in the step of firing the dry film 11 to form the conductor 10. As shown in FIG. 2 (C), in the firing step, the inorganic powder 1 moves toward the surface of the dry film 11 or the conductor portion 2 (conductor 10), and gradually appears to be present on the surface more than the inside. become. Although it does not specifically limit as this reason, since the sintering start temperature of the inorganic powder 1 is higher than the sintering start temperature of the conductive powder, the inorganic powder 1 is used when the conductive powder is sintered in the firing step. However, it is possible to move so that it may be extruded to the outer side (surface) of the dry film | membrane 11. In the conductor 10 obtained after firing, the inorganic powder 1 is present on the surface of the conductor 10 more than the inside.

In addition, the inorganic powder 1 should just exist more than the inside of the conductor 10 in the surface on the opposite side to the surface which contact | connects the board | substrate part 20, for example, may exist also in the surface which contact | connects the board | substrate part 20. FIG. In addition, the inorganic powder 1 is disposed on the surface opposite to the surface in contact with the substrate portion 20 in the conductor obtained by reacting with the substrate on the surface in contact with the substrate portion 20 and alloying, for example. May be. Hereinafter, the inorganic powder 1 will be described in detail.

[Inorganic powder]
In the conductor-forming composition, the inorganic powder 1 has an average particle size (SEM average particle size) based on scanning electron microscope (SEM) measurement of 0.3 μm or more and 5.0 μm or less. When the SEM average particle size is in the above range, the obtained conductor has a low resistance value, can have excellent conductivity, and can suppress the bonding of the conductor to other members. Moreover, when the SEM average particle diameter is in the above range, it can be suitably used particularly for fine-lined electronic components.

On the other hand, when the SEM average particle size is less than 0.3 μm, the inorganic powder 1 may be buried in the conductor, and the joint prevention effect may be insufficient. Moreover, when the SEM average particle diameter is more than 5.0 μm, the resistivity of the obtained conductor may be increased. The SEM average particle size of the inorganic powder 1 was measured using a scanning electron microscope (SEM) at a magnification at which 300 or more particles that can be seen in the entire shape of the particle can be confirmed in the photograph. The diameter of each particle was calculated from the average value of the longest diameter and the shortest diameter, and was determined by the average value of the diameters of the obtained inorganic powders (total calculated diameter of each particle / number of particles measured, number average). In the present specification, the SEM average particle size has the same meaning in other portions. The magnification when observing with SEM can be arbitrarily set as long as 300 or more can be confirmed as described above, but in the case of the inorganic powder used in the present invention, the magnification is observed in the range of 1,000 to 20,000 times. Is preferred.

The inorganic powder 1 may be a powder composed of particles that are not sintered when the conductor-forming composition is fired at a temperature at which the conductive powder can be sintered. That is, the inorganic powder 1 has a sintering start temperature higher than that of the conductive powder. For example, particles that are not sintered when fired (heat treated) at 120 ° C. or higher and 900 ° C. or lower in the air atmosphere can be used. When such particles are used, as described above, when the dried film formed from the conductor-forming composition is fired, the inorganic powder 1 can be distributed unevenly to the surface of the conductor.

The inorganic powder 1 is not particularly limited as long as it is a powder having the above characteristics, and a known powder material used for a conductor-forming composition can be used. As the inorganic powder 1, for example, ceramic powder can be used, but preferably, at least one of metal powder, metal oxide powder, and metal powder having an oxide film can be used, more preferably. At least one of copper powder, copper oxide powder, and copper powder having an oxide film can be used. When a powder containing copper is used as the inorganic powder 1, most of the powder is biased to the side opposite to the surface in contact with the substrate, but the powder remaining on the substrate side also has an effect of improving the adhesion with the substrate. preferable.

In addition, as the inorganic powder 1, insulating particles can be used. For example, a powder (for example, alumina powder) made of the same material as the substrate 11 can be used.

The inorganic powder 1 is preferably contained in an amount of 10 to 45 parts by mass, and more preferably 15 to 45 parts by mass with respect to 100 parts by mass of the conductive powder. When the content of the inorganic powder 1 is less than 10 parts by mass, the joint prevention effect may be insufficient. When the content of the inorganic powder 1 is more than 45 parts by mass, the powder may be easily transferred to another adjacent member, or the resistivity of the obtained conductor may be increased.

In addition to the inorganic powder 1, the conductor-forming composition of the present embodiment includes a conductive powder, a glass frit, and an organic vehicle. These components are not particularly limited, and known powder materials used for the conductor-forming composition can be used. Hereinafter, an example of each component constituting the conductor-forming composition will be described.

[Conductive powder]
The conductive powder is not particularly limited, and a known conductive powder used for the conductor-forming composition can be used. The conductive powder can include, for example, at least one of Au, Ag, Pd, and Pt. Further, the conductive powder can be contained in an amount of 30% by mass or more and 60% by mass or less based on the entire conductor-forming composition.

[Glass frit]
The glass frit is not particularly limited, and a known glass frit used for the conductor-forming composition can be used. As the glass frit, for example, a glass frit having an average particle size of 0.5 μm or more and 5 μm or less and a softening point of 500 ° C. or more and 700 ° C. or less can be used. The glass frit is preferably a lead-free glass frit, and specifically, a glass frit substantially free of alkali metal such as borosilicate glass (SiO ₂ —B ₂ O ₃ series) can be used. Glass frit is made of CaO, BaO, ZnO, TiO ₂ , V ₂ O ₅ or the like for the purpose of improving the wettability between glass and substrate, the adhesion between the substrate and conductor, and further improving the oxidation resistance of the conductor. It may be included as a component. Further, the glass frit can be contained in the range of 0.1% by mass or more and 5% by mass or less with respect to the entire conductor-forming composition.

[Organic vehicle]
The organic vehicle is obtained by dissolving a binder resin in a solvent. The binder resin is not particularly limited, and a resin similar to the conventional one can be used. For example, ethyl cellulose, methacrylate or the like can be used. The binder resin is preferably contained in the range of 1% by mass to 10% by mass with respect to the conductor-forming composition. When the content of the binder resin is less than 1% by mass, the handling property of the conductor-forming composition is poor, and the viscosity characteristic as a paste necessary for forming a conductor may not be obtained. On the other hand, when the content of the binder resin exceeds 10% by mass, the binder resin easily overflows on the surface of the obtained dry film, and the overflowing binder resin covers the inorganic powder 1 and adheres to other adjacent members. The obtained conductor and other members may be joined.

The solvent is not particularly limited, and a known solvent can be used. For example, an organic solvent such as terpineol or butyl carbitol can be used.

[Solvent for adjusting viscosity]
The conductor-forming composition of this embodiment may further contain a solvent for adjusting the viscosity when the paste is produced. The solvent for adjusting the viscosity is not particularly limited, and a known solvent can be used. For example, an organic solvent such as terpineol or butyl carbitol can be used. The solvent for adjusting the viscosity may be the same as or different from the solvent contained in the organic vehicle. Moreover, content of the solvent in the whole conductor formation composition can be adjusted suitably, for example, can be 20 mass% or more and 60 mass% or less with respect to the whole conductor formation composition.

The manufacturing method of the composition for forming a conductor according to this embodiment is not particularly limited, and a conventionally known manufacturing method can be used. For example, the conductive powder, the inorganic powder 1, the glass frit, and the organic vehicle are used. Can be manufactured by mixing with a three-roll mill or the like.

FIG. 3 is a flowchart showing an example of a method for producing a conductor of the present embodiment produced using the above-described conductor-forming composition. Hereinafter, with reference to FIG. 3, the manufacturing method of the conductor of this embodiment is demonstrated.

First, the conductor forming composition is applied to at least one surface of the substrate (step S1). Application | coating can use screen printing etc., for example. As the substrate, for example, a slit substrate having a slit can be used. In a later step, the slit substrate is divided along the slits to form respective chip components. When using a slit substrate, the substrate portion 20 shown in FIGS. 1 and 2 is a substrate portion corresponding to one chip in a chip component (for example, a chip resistor).

Next, the substrate coated with the conductor-forming composition is dried to form a dry film on the substrate (step S2). The drying conditions are not particularly limited as long as at least a part of the solvent contained in the conductor-forming composition can be removed. Drying temperature is 80 degreeC or more and 150 degrees C or less, for example. Drying time is 1 minute or more and 15 minutes or less, for example.

When applying the conductor forming composition to both surfaces (front and back surfaces) of the substrate, after applying and drying on one surface of the substrate by screen printing or the like, the conductor formation is similarly applied to the other surface of the substrate. Apply composition for drying. Through this step, for example, as shown in FIG. 2A, a pair of dry films 11 having a predetermined interval on both the back surface and the front surface of the substrate portion 20 can be obtained.

Next, the substrate on which the dry film is formed is baked (step S3). In the firing step (step S3), the conductive powder contained in the conductor-forming composition is sintered to form the conductor portion 2 as shown in FIG. Further, as firing proceeds, the inorganic powder 1 is present on the surface more than the inside opposite to the surface in contact with the substrate. The firing conditions are not particularly limited, and the conditions under which the conductive powder is sintered can be used, but it is preferably performed in an air atmosphere. The firing temperature is, for example, 600 ° C. or higher and 900 ° C. or lower. When firing using a belt furnace, in consideration of the conveyance speed, it is set to be held at a peak temperature set at 600 ° C. or higher and 900 ° C. or lower for a predetermined time, for example, 1 minute or longer and 15 minutes or shorter.

When the conductor-forming composition contains a metal powder as the inorganic powder 1, the metal powder can react with oxygen in the air during firing to form a metal oxide powder or a metal powder having an oxide film. When the inorganic powder 1 is a copper powder, the copper powder reacts with oxygen in the atmosphere during firing to form a copper oxide powder or a copper powder having an oxide film. It is preferable to use copper powder as the inorganic powder 1 because it is excellent in adhesion to the substrate. In addition, as the inorganic powder 1 used for the conductor forming composition, a copper oxide powder or a copper powder having an oxide film may be used directly.

FIG. 4 is a schematic diagram showing an example of the resistor of the present embodiment. The resistor 100 includes at least the substrate 20, the conductor 10, and the resistor 30. The resistor 100 includes a protective layer 40 such as a glass layer or a resin layer on the resistor 30.

The conductor 10 which comprises the resistor 100 contains the surface electrode 10a and the back surface electrode 10b, as shown in FIG. The front electrode 10a and / or the back electrode 10b are formed using the conductor forming composition. The conductor 10 includes an end face electrode 10c. The conductor 10 obtained using the conductor-forming composition has a low resistance value and excellent conductivity, so that it can be suitably used for fine-lined electronic components.

Hereinafter, the present invention will be further described with reference to examples, but the scope of the present invention is not limited by the examples. Hereinafter, details of each example and comparative example will be described.

Example 1
[Preparation of conductor forming composition (conductive paste)]
In advance, an organic vehicle containing 15% by mass of ethyl cellulose as the binder resin in the organic vehicle and 85% by mass of terpineol as the solvent in the organic vehicle was prepared.
Next, as the conductive powder, Ag powder is 50% by mass with respect to the entire conductive paste, Cu powder having an SEM average particle size of 1.0 μm is 20 parts by mass with respect to 100 parts by mass of the conductive powder, and glass frit is the conductive paste. A 3 roll mill (Bueller Co., Ltd., SDY-) was added in an amount such that 3.0% by mass of the organic vehicle and 3.0% by mass of ethyl cellulose with respect to the entire conductive paste. 300), and finally a solvent for viscosity adjustment was added to prepare a paste-like conductor-forming composition (conductive paste).

[Dry film and conductor production]
The obtained conductive paste was printed on a 96% alumina substrate in a predetermined pattern (width 20 mm × length 20 mm) using a screen printer, and dried at 150 ° C. for 5 minutes using a belt-type drying furnace. A dry film (film thickness 15 μm) was formed. Next, the dried film was placed in contact with the belt of the belt furnace and fired at a peak temperature of 850 ° C. for 9 minutes for a total of 50 minutes to form a conductor.

[Evaluation of joining with belt]
The formed conductor was evaluated by visually observing the contact portion with the belt or with an optical microscope, and visually observing the presence or absence of bonding and the presence or absence of transfer (inorganic powder adhesion) to the belt. The evaluation results are shown in Table 1. Moreover, the observation result by the optical microscope of a conductor (conductive film) is shown in FIG. A portion indicated by an arrow corresponds to a contact portion (joint portion) with the belt.

[Measurement of conductor thickness and resistance]
The thickness of the obtained conductor was measured using a stylus type surface roughness meter (manufactured by Tokyo Seimitsu Co., Ltd., SURFCOM 480A). Next, using a digital multimeter (manufactured by ADVANTEST, R6871E), the resistance value of the conductor pattern having a width of 0.5 mm and a length of 50 mm was measured, and the film thickness measured previously was set to 5 μm. The resistance value when converted was calculated. The measurement results are shown in Table 1.

(Example 2)
A conductive paste was produced under the same conditions as in Example 1 except that the SEM average particle size of the Cu powder was changed to 4.0 μm. The measurement results are shown in Table 1.

(Example 3)
A paste was prepared in the same manner as in Example 1 except that the Cu powder content was changed to 40 parts by mass with respect to 100 parts by mass of the conductive powder. The measurement results are shown in Table 1.

Example 4
A conductive paste was produced under the same conditions as in Example 1 except that the Cu powder (inorganic powder) was changed to CuO powder. The measurement results are shown in Table 1.

(Example 5)
A conductive paste was produced under the same conditions as in Example 1 except that the Cu powder (inorganic powder) was changed to alumina powder. The measurement results are shown in Table 1.

(Comparative Example 1)
A paste was prepared in the same manner as in Example 1 except that the SEM average particle size of the Cu powder was changed to 0.1 μm. The measurement results are shown in Table 1.

(Comparative Example 2)
A paste was prepared in the same manner as in Example 1 except that the SEM average particle size of the Cu powder was changed to 10.0 μm. The measurement results are shown in Table 1.

(Comparative Example 3)
A paste was prepared in the same manner as in Example 1 except that the content of the Cu powder was changed to 2.0 parts by mass with respect to 100 parts by mass of the conductive powder. The measurement results are shown in Table 1.

(Comparative Example 4)
A paste was prepared in the same manner as in Example 1 except that the Cu powder content was changed to 50 parts by mass with respect to 100 parts by mass of the conductive powder.

(Evaluation results)
The conductor obtained in the example had a film thickness of about 7 μm to 9 μm, and a resistance value in terms of 5 μm was 20 mΩ or more and 40 mΩ or less. The resistance value in terms of 5 μm could be 25 mΩ or less depending on the conditions. Further, when the surfaces of these conductors were visually and SEM-observed, the joining with the belt and the transfer to the belt were not confirmed. In FIG. 5, the photograph which observed the part of the belt which mounted the conductor formed using the composition of Example 1 by SEM is shown. The portion of the belt on which the conductor was placed was confirmed, but the constituent components of the conductor and the adhesion of Cu powder were not confirmed.

On the other hand, the conductor formed using the composition of Comparative Example 1 uses an inorganic powder having an SEM average particle size of 0.1 μm, and it was visually confirmed that the surface of the portion placed on the belt was deformed. . In FIG. 6, the photograph which observed the part of the belt which mounted the conductor part formed using the composition of the comparative example 1 by SEM is shown. As shown in FIG. 6, it was confirmed that the conductor formed using the composition of Comparative Example 1 was peeled off from the surface of the conductor (film), joined to the belt, and transferred.

The conductor formed using the composition of Comparative Example 2 uses an inorganic powder having an SEM average particle diameter of 10 μm, and the resistance value in terms of 5 μm was as high as 51.2 mΩ. In addition, no trace of bonding with the belt was confirmed on the surface of the conductor, and no adhesion of the constituent components of the conductor and Cu powder was confirmed on the belt in contact with the conductor.

The conductor formed using the composition of Comparative Example 3 had an inorganic powder content of less than 10 parts by mass, and it was visually confirmed that the surface of the part placed on the belt was deformed. As a result of SEM observation, it was confirmed that the surface of the conductor was peeled off, joined to the belt, and transferred.

The conductor formed using the composition of Comparative Example 4 had an inorganic powder content of more than 45 parts by mass and a high resistance value of 65.7 mΩ in terms of 5 μm. When the surface of the conductor was visually and SEM-observed, bonding with the belt was not confirmed. On the other hand, when a portion in contact with the conductive film of the belt was confirmed, it was confirmed that a part of the Cu powder was transferred.

Note that the technical scope of the present invention is not limited to the above embodiment. For example, one or more of the requirements described in the above embodiments may be omitted. The requirements described in the above embodiments can be combined as appropriate. In addition, as long as it is permitted by law, the contents of Japanese Patent Application No. 2017-104658, which is a Japanese patent application, and all the references cited in the above-described embodiments, etc., are incorporated into the description of this text.

DESCRIPTION OF SYMBOLS 1 ... Inorganic substance powder 2 ... Conductor part 10 ... Conductor 10a ... Surface electrode 10b ... Back electrode 10c ... End face electrode 11 ... Dry film 20 ... Substrate part 25 ... Belt member 30 ... Resistor 40 ... Protective layer 100 ... Resistor

Claims

A conductor-forming composition comprising a conductive powder, an inorganic powder other than the conductive powder, a glass frit, and an organic vehicle,
The inorganic powder has an average particle size based on SEM measurement of 0.3 μm or more and 5.0 μm or less, has a sintering start temperature higher than that of the conductive powder, and is 10 per 100 parts by mass of the conductive powder. A composition for forming a conductor, which is contained in an amount of from 45 parts by weight to 45 parts by weight.
2. The conductor-forming composition according to claim 1, wherein the inorganic powder includes at least one of a metal powder, a metal oxide powder, and a metal powder having an oxide film.
3. The conductor-forming composition according to claim 2, wherein the inorganic powder includes at least one of copper powder, copper oxide powder, and copper powder having an oxide film.
The organic vehicle includes a binder resin and a solvent, and the binder resin is included in an amount of 1% by mass to 10% by mass with respect to the conductor-forming composition. The composition for conductor formation as described in any one of.
The conductor-forming composition according to any one of claims 1 to 4, wherein the conductive powder contains at least one of Au, Ag, Pd, and Pt.
When the conductor-forming composition is baked in contact with a belt member using a belt furnace, the inorganic powder is present on the surface more than the inside of the conductor, whereby the conductive powder is applied to the belt member. The composition for forming a conductor according to any one of claims 1 to 5, which can prevent seizure.
The conductor forming composition according to any one of claims 1 to 6, which is used for forming at least one of a front electrode and a back electrode of a chip resistor.
Applying the composition for forming a conductor according to any one of claims 1 to 7 to at least one surface of a substrate;
Drying the substrate coated with the conductor-forming composition, removing at least a portion of the solvent contained in the conductor-forming composition, and forming a dry film on the substrate;
The substrate on which the dry film is formed is fired to sinter the conductive powder contained in the conductor-forming composition, and the inorganic powder is more on the surface opposite to the surface in contact with the substrate than inside. Forming an existing conductor;
A method for producing a conductor.
The conductor-forming composition includes a metal powder as the inorganic powder, and the metal powder reacts with oxygen in the atmosphere during firing to form a metal powder having a metal oxide powder or an oxide film. The method for producing a conductor according to 8.
The method for producing a conductor according to claim 9, wherein the inorganic powder is a copper powder.
A conductor formed on a substrate using the conductor-forming composition according to any one of claims 1 to 7, wherein the inorganic powder is a side of the conductor opposite to a surface in contact with the substrate. A conductor that is biased to the surface.
An electronic component having a conductor formed using the conductor-forming composition according to any one of claims 1 to 7.
A chip resistor comprising at least a substrate, a conductor, and a resistor, wherein the conductor is formed using the conductor-forming composition according to any one of claims 1 to 7.