JP7245418B2 - Composition for thick film resistor, paste for thick film resistor, and thick film resistor - Google Patents

Description

The present invention provides a composition for a thick film resistor and a paste for a thick film resistor, which are used for forming a thick film resistor in a resistance component such as a chip resistor or a hybrid IC, and a composition formed using these It relates to thick film resistors.

2. Description of the Related Art Conventionally, as a resistance component among electronic components, there are a thick film resistor formed using a resistance paste and a thin film resistor formed by sputtering a film forming material. Among these, thick-film resistors are widely used as resistance components such as chip resistors and hybrid ICs because of their low manufacturing facilities and high productivity.

A thick film resistor is formed by printing a paste for a thick film resistor on a ceramic substrate and firing the paste. This thick-film resistor paste is substantially composed of conductive powder, glass frit, and an organic vehicle for making these pastes suitable for printing.

Ruthenium (Ru) compounds such as ruthenium dioxide (RuO ₂ ) and pyrochlore-type ruthenium-based oxides (Pb ₂ Ru ₂ O _7-X , Bi ₂ Ru ₂ O ₇ ) are generally used as the conductive powder. ing. The reason why ruthenium dioxide and ruthenium compounds are used as the conductive powder is mainly that they have the characteristic that the resistance value changes smoothly with changes in their concentration.

However, in these ruthenium-based materials, there is a limit to lowering the resistance value, and the lower limit of the area resistance value is about 10Ω/□, and practically about 100Ω/□.

On the other hand, in JP-A-04-206602, as the conductive powder, a precious metal powder, more specifically, a composition of 44% to 47% by weight of silver and 53% to 56% by weight of palladium Compositions for thick film resistors employing noble metal powders are disclosed. Compositions for thick film resistors comprising these noble metal powders and ruthenium-based material powders are also known. Thick film resistors formed using these compositions for thick film resistors have low area resistance values in the range of 100 mΩ/□ to 10 Ω/□.

In JP-A-11-288801, as the conductive powder, a copper-based conductor, more specifically, a mixed powder of copper powder and nickel powder (Cu/Ni = 60/40 to 80/20). A film resistor paste is disclosed. This copper-based thick-film resistor paste can be obtained at a lower cost than the silver-based thick-film resistor paste. A thick film resistor is formed by firing such a thick film resistor paste in a nitrogen atmosphere.

JP-A-04-206602 JP-A-11-288801

However, silver and palladium have the problem of being expensive. In particular, in order to improve the temperature characteristics of the thick film resistor, it is necessary to use a large amount of very expensive palladium. Electromigration may also occur in silver-based electrodes and resistors.

Further, the thick film resistor using copper and nickel has a sheet resistance value of less than 1 Ω/□, and a thick film resistor having a sheet resistance value in the range of 1 Ω/□ to 10 Ω/□ is obtained. can't It is possible to increase the sheet resistance of the thick film resistor to 1 Ω/□ or more by increasing the amount of glass in the thick film resistor.

The present invention provides a thick film having a sheet resistance value in the range of 100 mΩ/□ to 15 Ω/□ and having good properties without using expensive materials such as silver, palladium, and ruthenium-based materials. An object of the present invention is to provide a resistor, and a thick film resistor composition and a thick film resistor paste for forming such a thick film resistor.

A composition for a thick film resistor of the present invention comprises a conductive powder and a glass frit substantially free of lead,
the conductive powder comprises copper, nickel, and lanthanum nickelate;
The content of copper is in the range of 30% by mass to 70% by mass, the content of nickel is in the range of 10% by mass to 35% by mass, and the content of lanthanum nickelate is in the range of 0% by mass to 20% by mass. % by mass or less, and the content of the glass frit is in the range of 5% by mass to 50% by mass,
It is characterized by

The conductive powder is composed of a powder made of copper and nickel and a powder of lanthanum nickelate, and the powder made of copper and nickel has an average particle size according to the BET method in the range of 0.1 μm to 3.0 μm. The lanthanum nickelate powder preferably has an average particle size measured by the BET method in the range of 0.01 μm to 0.2 μm.

The glass frit preferably has an average particle size _D50 according to laser particle size distribution measurement of 5 μm or less.

The thick film resistor paste of the present invention contains a thick film resistor composition and an organic vehicle, and the thick film resistor composition of the present invention is used as the thick film resistor composition. It is characterized by

The content of the organic vehicle is preferably in the range of 20% by mass to 50% by mass with respect to the entire thick film resistor paste.

The thick film resistor of the present invention comprises a fired body containing a conductive component and a glass component substantially free of lead,
the conductive component comprises copper, nickel, and lanthanum nickelate;
The copper content is in the range of 30% by mass to 70% by mass, the nickel content is in the range of 10% by mass to 35% by mass, and the lanthanum nickelate content is 0% by mass to 20% by mass. % by mass or less, and the content of the glass component is in the range of 5% by mass to 50% by mass,
It is characterized by

According to the present invention, copper- and nickel-based, that is, without using expensive silver, palladium, and ruthenium-based materials, has good properties and has a resistance of 100 mΩ/square to 15 Ω/square. It is possible to provide a low resistance thick film resistor with a range of area resistance values.

Hereinafter, the composition for thick film resistors, the paste for thick film resistors, and the thick film resistors of the present invention will be described in detail.

(1) Thick Film Resistor Composition The thick film resistor composition of the present invention contains conductive powder and glass frit as main components.

[Conductive powder]
The conductive powder constituting the composition for thick film resistors of the present invention consists of copper, nickel and lanthanum nickelate.

Although the form in which the conductive powder exists is not limited, the conductive powder of the present invention is usually composed of a powder made of copper and nickel and a lanthanum nickelate powder.

The form of existence of the powder made of copper and nickel is also not limited. That is, any of mixed powder of copper powder and nickel powder, copper-nickel composite powder, and copper-nickel alloy powder can be used.

It is preferable that the average particle diameter of these powders composed of copper and nickel as determined by the BET method is in the range of 0.1 μm to 3.0 μm.

Lanthanum nickelate (LaNiO ₃ : abbreviated as “LNO”), which constitutes the lanthanum nickelate powder among the conductive powders, has a perovskite-type crystal structure and is a metallic conductive oxide with relatively low electrical resistance. It is a thing. Similar to the function of ruthenium dioxide in silver-based resistors, lanthanum nickelate has the function of stabilizing the electrically unstable state of metal and glass alone. Therefore, it has a function of sufficiently lowering the resistance value of the thick film resistor.

In the present invention, the average particle size of the lanthanum nickelate powder measured by the BET method is preferably in the range of 0.01 μm to 0.2 μm, more preferably in the range of 0.05 μm to 0.1 μm. As a result, in the thick-film resistor obtained by firing, the conductive paths become finer, and variations in the resistance value thereof can be suppressed.

The "average particle size according to the BET method" is calculated from the specific surface area assuming that the powder particles are spherical, and can be obtained by the following formula.
Average particle size (μm)={6/(theoretical density (g/cm ³ )×specific surface area (m ² /g))}

In the thick film resistor composition of the present invention, the copper content is in the range of 30% by mass to 70% by mass, the nickel content is in the range of 10% by mass to 35% by mass, and lanthanum nickelate The content is more than 0% by mass and 20% by mass or less.

The content of lanthanum nickelate is appropriately determined according to the resistance value of the thick film resistor. The resistive film forming the film resistor becomes fragile. In addition, considering the blendability, it is necessary to blend lanthanum nickelate in a small amount exceeding 0% by mass even when the thick film resistor is configured to have a low resistance.

The contents of copper and nickel are also appropriately determined according to the resistance value of the thick film resistor. When reducing the temperature coefficient of resistance (TCR) of the thick film resistor, the content ratio of copper and nickel should be in the range of 75:25 to 65:35. is preferred, and 70:30 is more preferred.

There are no particular restrictions on the method for producing each powder that constitutes the conductive powder, and powders obtained by various production methods can be used.

In the composition for a thick film resistor of the present invention, the content of the powder composed of copper and nickel and the lanthanum nickelate powder, which constitute the conductive powder, is determined by the resistance value of the thick film resistor, the conductive powder and the glass. It is adjusted appropriately according to the type and particle size of the frit. For example, when the area resistance value is 100 mΩ/□ to 1 Ω/□, the content of the powder made of copper and nickel is relatively increased, and the content of the lanthanum nickelate powder and the glass frit powder is relatively increased. to less. When the area resistance value is 1 Ω/□ or more, as the area resistance value increases, the content of the powder composed of copper and nickel is relatively decreased, and the content of the lanthanum nickelate powder and the glass frit powder is reduced. Relative increase.

[Glass frit]
The glass frit constituting the composition for a thick film resistor of the present invention is made of glass substantially free of lead.

Here, "substantially free of lead" in the glass frit means that the lead content in the glass frit is the RoHS directive regulation value (0.1% by mass) or less, or the lead content is It means that it is below the detection limit in normal measuring equipment.

Other glass components in the glass frit constituting the composition for thick film resistors of the present invention are basically not limited. Alkaline earth zinc aluminoborosilicate glass (SiO ₂ —B ₂ O ₃ —RO—ZnO—Al ₂ O ₃ : R is at least one selected from Ca, Sr, and Ba), borosilicate glass as glass frit (SiO ₂ —B ₂ O ₃ ), aluminoborosilicate glass (SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ ), or alkaline earth borosilicate glass (SiO ₂ —B ₂ O ₃ —RO: R is Ca , Sr, and Ba) can be suitably used.

The glass frit preferably has an average particle size D ₅₀ according to laser particle size distribution measurement of 5 μm or less, in particular in the range from 0.5 μm to 5.0 μm. In order to obtain a glass frit having a desired average particle size, the melted and cooled glass frit may be pulverized using a known pulverization method such as a ball mill or a jet mill. The average particle size D ₅₀ of the glass frit determined by laser particle size distribution measurement is preferably in the range from 1.0 μm to 3.0 μm.

The content of the glass frit in the composition for thick film resistors is also appropriately adjusted according to the desired resistance value in the resulting thick film resistor, the types and particle sizes of the conductive powder and glass frit, as described above. be done. The glass frit content is preferably in the range of 5% to 60% by mass, more preferably in the range of 5% to 50% by mass, and in the range of 7% to 30% by mass. is more preferred.

[Optional ingredients]
In addition to the conductive powder and the glass frit, other additives may be added to the thick film resistor composition of the present invention. For example, in a thick film resistor, the thick film resistor of the present invention is used for the purpose of adjusting electrical characteristics such as resistance value and temperature coefficient of resistance, temperature characteristics, adjusting expansion coefficient, improving voltage resistance, and other modifications. The body composition can optionally contain inorganic ingredients such as manganese oxide, copper oxide, niobium oxide, tin oxide, tantalum oxide and titanium oxide.

The content of these inorganic components is generally in the range of 0.05% by mass or more and 10% by mass or less with respect to the total mass of the conductive powder and the glass frit.

(2) Thick film resistor paste The thick film resistor paste of the present invention comprises a thick film resistor composition and an organic vehicle. A composition for a membrane resistor is used. Specifically, the paste for thick film resistors of the present invention is composed of a kneaded product of the composition for thick film resistors of the present invention and an organic vehicle. Details will be described below.

[Organic vehicle]
The organic vehicle that constitutes the thick film resistor paste is composed of at least a resin and a solvent.

Examples of resins that can be used as organic vehicles include ethyl cellulose resins, acrylic resins, and methylstyrene resins. These resins are preferably resins that decompose at a temperature before the glass is softened when baked in a nitrogen atmosphere. A resin that decomposes at a temperature of 500° C. or less is more preferable.

As a solvent for dissolving the resin, terpineol, butyl carbitol, butyl carbitol acetate, etc. can be used.

The compounding ratio of the resin and the solvent in the organic vehicle prepared from these resins and the solvent can be appropriately adjusted depending on the desired viscosity and application.

In addition, a plasticizer having a high boiling point can be further added from the viewpoint of controlling the drying rate of the paste in consideration of the continuous printability required for the paste for thick film resistors. The blending ratio of the plasticizer in this case can also be appropriately adjusted according to the desired drying rate.

The content of the organic vehicle in the thick film resistor paste is not particularly limited, but is generally 20% by mass to 50% by mass with respect to the entire thick film resistor paste.

[Other ingredients]
The thick film resistor paste of the present invention can contain additives in addition to the thick film resistor composition and the organic vehicle. For example, a dispersant can be included from the viewpoint of preventing aggregation of the conductive powder and other inorganic components. Moreover, from the viewpoint of coating workability, a rheology control agent can be included.

[Method for preparing thick film resistor paste]
The thick film resistor paste may be prepared using a known technique, such as a three-roll mill, ball mill, or the like.

In pastes for thick film resistors, it is desirable to break up agglomeration of conductive powder, glass frit, and other inorganic components and to disperse them in an organic vehicle.

(3) Thick Film Resistor The thick film resistor of the present invention is made of a fired body containing a conductive component and a glass component. The conductive component includes copper, nickel and lanthanum nickelate. The glass component is characterized by being substantially free of lead. That is, the thick film resistor of the present invention is formed using the paste for thick film resistor of the present invention, and is composed of a fired body of the composition for thick film resistor of the present invention.

Therefore, the conductive component has the same composition as the conductive powder that constitutes the composition for thick film resistors of the present invention, and the glass component has the same composition as the glass frit that constitutes the composition for thick film resistors of the present invention. is the composition of Specifically, the copper content is in the range of 30% by mass to 70% by mass, the nickel content is in the range of 10% by mass to 35% by mass, and the lanthanum nickelate content is 0% by mass. more than 20% by mass or less. A detailed description of these is omitted here because it is the same as the content of the composition for thick film resistors.

A method for manufacturing a thick film resistor will be described below. Incidentally, the resistance value of the thick film resistor can be appropriately adjusted by the ratio of the conductive component and the glass component in the thick film resistor.

[Manufacturing method of thick film resistor]
The manufacturing method of the thick film resistor of the present invention is not limited to the following contents, and the processing conditions can be appropriately changed using known means and methods.

First, a coating step of coating a substrate with a thick-film resistor paste is performed. That is, an electrode made of copper or the like is formed on a ceramic substrate such as alumina (Al ₂ O ₃ ), and the thick film resistor paste of the present invention is applied thereon by means of screen printing or the like.

Next, a baking step is performed to bake the substrate coated with the paste for thick film resistors, thereby fabricating the thick film resistors. Specifically, in the coating step, the thick-film resistor paste applied to the substrate is dried using an oven or the like, and then baked in a nitrogen atmosphere using a belt furnace or the like to combine with the conductive component. A fired body containing a glass component is obtained. Basically, the components other than the conductive powder and the glass frit contained in the thick film resistor paste, that is, the resin and solvent constituting the organic vehicle, and the addition of other organic substances All the agents are decomposed through the firing process.

The thick-film resistor of the present invention is obtained through the steps described above.

The thick film resistor of the present invention is composed of at least a conductive component containing copper, nickel and lanthanum nickelate and a glass component substantially free of lead. Accordingly, a thick film resistor is provided which does not substantially contain lead, has a sheet resistance value in the range of 100 mΩ/square to 15 Ω/square, and has excellent characteristics.

[Resistance value]
The resistance value of the thick film resistor of the present invention is evaluated by the area resistance value calculated from the resistance value with the ratio of resistor width to resistor length being 1:100. The thick film resistor of the present invention has a sheet resistance value in the range of 100 mΩ/square to 15 Ω/square.

[Temperature coefficient of resistance (TCR)]
A temperature coefficient of resistance (TCR) is an index of thermal stability (temperature characteristics) of a thick film resistor. The temperature coefficient of resistance is calculated as follows. The unit of temperature coefficient of resistance is ppm/°C.

High temperature resistance temperature coefficient (HTCR) = [(R ₁₂₅ - R ₂₅ )/R ₂₅ (125 - 25)] x 10 ⁶
Low temperature temperature coefficient of resistance (CTCR) = [(R ₋₅₅ −R ₂₅ )/R ₂₅ (−55−25)]×10 ⁶

Here, _R25 is the resistance value at 25°C, _R125 is the resistance value at 125°C, and R _-55 is the resistance value at -55°C.

Both the high temperature temperature coefficient of resistance (HTCR) and the low temperature temperature coefficient of resistance (CTCR) are preferably within ±100 ppm/°C.

[Load characteristics]
The load characteristics serve as an index of the stability (stability of electrical characteristics) of the thick film resistor with respect to current load. In the present invention, the measured value (ΔR) of the rate of change in resistance when a 200 pF capacitor is charged at 2 kV and discharged five times to a resistor is used as the load characteristic.

This rate of change in resistance value (ΔR) is preferably 1% or less.

The thick film resistor of the present invention can contain inorganic components such as manganese oxide, copper oxide, niobium oxide, tin oxide, tantalum oxide, and titanium oxide in addition to the conductive component and the glass component.

In the foregoing, the present invention has been primarily described using specific embodiments, and also the best configuration, method, etc. for carrying out the present invention has been disclosed. However, the present invention is not limited to these. A person skilled in the art can make omissions, additions, changes or modifications to the above-described embodiments with respect to the shape, material, quantity, and other detailed configurations without departing from the scope of the technical idea and purpose of the present invention. Additions are possible and are also included in the scope of the present invention.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples of the present invention. However, the present invention is not limited by the following examples.

(Example 1)
[Composition for thick film resistor]
[Conductive powder]
Copper powder, nickel powder, and lanthanum nickelate powder were used as the conductive powder.

Atomized copper powder having an average particle size of 2.5 μm as determined by the BET method was used as the copper powder.

As the nickel powder, nickel powder having an average particle size of 0.5 μm according to the BET method obtained by hydrogen reduction of nickel hydroxide at 400° C. was used.

As the lanthanum nickelate powder, lanthanum nickelate powder having an average particle size of 0.05 μm according to the BET method, which was produced by roasting a coprecipitate obtained from nickel chloride, lanthanum nitrate and alkali, was used.

[Glass frit]
A glass frit having a composition of 37 wt % BaO-43 wt % SiO ₂ -7 wt % B ₂ O ₃ -13 wt % Al ₂ O ₃ was used as the glass frit. The glass frit was made by conventional means of mixing, melting, quenching, and grinding. The average particle size _D50 of the glass frit after the pulverization step was 2.0 μm, as measured using a laser particle size distribution analyzer.

Copper powder: 63.5% by mass, nickel powder: 27.2% by mass, lanthanum nickelate powder: 1.5% by mass, and glass frit: 7.7% by mass were mixed to form a thick film resistor composition. got stuff Table 1 shows the compositions of the compositions for thick film resistors.

[Paste for thick film resistors]
70% by mass of composition for thick film resistor and 30% by mass of organic vehicle mainly composed of acrylic and terpineol (acrylic:terpineol is 1:4) were mixed and kneaded in a triple roll mill. A resistor paste was prepared by

The thick-film resistor paste was screen-printed in a pattern of 0.5 mm width x 50 mm length on an alumina substrate on which electrodes had been formed in advance using copper paste. is dried at 150° C. for 10 minutes, and then the thick film resistor paste is fired at a peak temperature of 900° C. for 10 minutes in a nitrogen atmosphere using a belt firing furnace to form a thick film resistor. Obtained.

[Evaluation of thick film resistor]
Next, the characteristics (area resistance value, temperature coefficient of resistance (TCR), load characteristics) of the obtained thick film resistor were measured.

Here, the resistance value was measured by the 4-probe method using a multimeter (Model 2001 manufactured by KEITHLEY), and the area resistance value was calculated.

Next, the high-temperature temperature coefficient of resistance (HTCR) and the low-temperature temperature coefficient of resistance (CTCR) were calculated by the following equation using the obtained sheet resistance values. The unit of temperature coefficient of resistance is ppm/°C.

High temperature resistance temperature coefficient (HTCR) = [(R ₁₂₅ - R ₂₅ )/R ₂₅ (125 - 25)] x 10 ⁶
Low temperature temperature coefficient of resistance (CTCR) = [(R ₋₅₅ −R ₂₅ )/R ₂₅ (−55−25)]×10 ⁶

Here, _R25 is the resistance value at 25°C, _R125 is the resistance value at 125°C, and R _-55 is the resistance value at -55°C.

Also, as load characteristics, a rate of change in resistance value obtained by measuring a charge charged at 2 kV in a 200 pF capacitor at 2 kV to a thick film resistor and measuring it was obtained.

Table 2 shows the characteristics of each thick film resistor.

For Examples 2 and 3 and Comparative Examples 1 to 4, the thick film resistor composition was prepared in the same manner as in Example 1 except that the composition of the thick film resistor composition was changed as shown in Table 1. A paste and a thick film resistor were prepared, and the properties of the resulting thick film resistor were measured. Table 1 also shows the characteristics of the thick film resistors of Examples 2 and 3 and Comparative Examples 2 and 4. In Comparative Example 1, the characteristics were not evaluated because the resistive film constituting the thick film resistive element was fragile.

From the comparison of the characteristics of the thick film resistors produced in the above examples and comparative examples, the thick film resistor according to the present invention has a sheet resistance value in the range of 100 mΩ/□ to 15 Ω/□, and The absolute values of the high temperature resistance temperature coefficient (HTCR) and the low temperature resistance temperature coefficient (CTCR) as well as the resistance value change rate, which indicates the load characteristics, are small. is.

Claims (6)

comprising a conductive powder and a glass frit substantially free of lead;
the conductive powder comprises copper, nickel, and lanthanum nickelate;
The content of copper is in the range of 30% by mass to 70% by mass, the content of nickel is in the range of 10% by mass to 35% by mass, and the content of lanthanum nickelate is in the range of 0% by mass to 20% by mass. % by mass or less, and the content of the glass frit is in the range of 5% by mass to 50% by mass. The conductive powder is composed of a powder made of copper and nickel and a powder of lanthanum nickelate, and the powder made of copper and nickel has an average particle size according to the BET method in the range of 0.1 μm to 3.0 μm. 2. The composition for a thick film resistor according to claim 1, wherein said lanthanum nickelate powder has an average particle size according to the BET method in the range of 0.01 μm to 0.2 μm. 3. The composition for a thick film resistor according to claim 1, wherein said glass frit has an average particle size _D50 according to laser particle size distribution measurement of 5 [mu]m or less. A thick film comprising a composition for a thick film resistor and an organic vehicle, wherein the composition for a thick film resistor according to any one of claims 1 to 3 is used as the composition for a thick film resistor. Paste for resistors. 5. The thick film resistor paste according to claim 4, wherein the content of said organic vehicle is in the range of 20% by mass to 50% by mass with respect to said entire thick film resistor paste. Consisting of a fired body containing a conductive component and a glass component substantially free of lead,
the conductive component comprises copper, nickel, and lanthanum nickelate;
The copper content is in the range of 30% by mass to 70% by mass, the nickel content is in the range of 10% by mass to 35% by mass, and the lanthanum nickelate content is 0% by mass to 20% by mass. % by mass or less, and the content of the glass component is in the range of 5% by mass to 50% by mass.
thick film resistor.