KR0159032B1 - Resistive paste - Google Patents

Abstract

The present invention relates to a resistive paste which is characterized by containing the following _{components: (a) Nb x La 1} - x B 6 - 4x resistance material having a composition of (where x is 0.1 to 0.9 mole) (a1 ) And a solid containing a non-reducing glass frit (a2); (b) TiO ₂ added as an amount of 1-10 weight% with respect to the said solid content; (c) at least one member selected from the group consisting of Co ₃ O ₄ , CoO and Fe ₂ O ₃ added as an amount of 1 to 10% by weight based on the solid content; And (d) organic vehicles.

Description

Resistance paste

The present invention relates to a resistive paste, which can be sintered in a neutral or reducing atmosphere and has an improved resistance temperature coefficient.

Generally, an electric circuit pattern composed of electrodes, resistors, etc., on which various electronic components are mounted, has been formed on a ceramic substrate made of alumina or the like. In general, electrodes are formed by screen printing a paste containing a noble metal such as silver (Ag) or a silver-palladium alloy (Ag-Pd) on a ceramic substrate and then sintering in air.

However, in view of the fact that the precious metal paste is too expensive, and also the migration resistance of the resistance paste sufficient to cope with the reduction in the distance between the electrodes due to the miniaturization of electronic devices or components, the precious metal paste has recently been copper, It is replaced by nonmetallic pastes, such as nickel and aluminum. Such a non-metallic paste may be screen printed on a ceramic substrate and sintered in a neutral or reducing atmosphere to form a cheap electrode pattern having excellent characteristics.

When forming an electrode using such a non-metallic paste, the resistors arranged to bridge the electrodes must also use a resistor paste capable of sintering in a neutral or reducing atmosphere. Known resistance pastes that can be sintered in a neutral or reducing atmosphere include LaB _6- based pastes (see Japanese Patent Application Publication No. 59-6481), NbB _2- based pastes (see Japanese Patent Application Publication No. 63-224301), and Nb-La. -B type paste (refer Japanese Unexamined-Japanese-Patent No. 2-249203).

A wide range of surface resistivity has been obtained by varying the mixing ratio of the resist material and the glass frit (low melting glass powder). However, in the case of using a LaB _6- based or NbB _2- based resist paste, since the affinity between the resist material and the glass frit is not good, the area resistance varies significantly even with a slight change in the amount of glass frit. There is a thing. For this reason, the area resistance value which can obtain satisfactory reproducibility has been limited.

On the other hand, the resistor formed of the Nb _x La _1-x B _6-4x -based paste shows a gentle increase in area resistance compared to the resistor formed of the LaB _6- based or NbB _2- based paste. Therefore, Nb _x La _1-x B _6-4x series pastes vary from 10Ω / □ to 10MΩ / □ (where □ stands for square) as the mixing ratio of the resist material and glass frit changes. A wide range of area resistance can be obtained. However, a resistor formed with an Nb _x La _1-x B _6-4x- based paste, particularly a resistor adjusted to have a low area resistance (about 10 to 100? /?), Is referred to as its temperature coefficient of resistivity (hereinafter referred to as TCR). ) Shifts in the positive direction, and its absolute value tends to deviate from zero. In this respect, they do not always meet the characteristics required in practical use.

An object of the present invention can be sintered in a neutral or reducing atmosphere, and Nb _x La _1-x B ₆ in which the TCR in a region having low area resistance moves in the negative direction to bring the absolute value closer to zero. To provide a _-4x resistor paste

Other objects and effects of the present invention will become more apparent from the following detailed description.

The present invention relates to a resistance paste containing the following components:

(a) a solid containing a resistive material (a1) having a composition of Nb _x La _1-x B _6-4x (where x is 0.1 to 0.9 mol) and a non-reducing glass frit (a2);

(b) TiO ₂ added as an amount of 1-10 weight% with respect to the said solid content;

(c) at least one member selected from the group consisting of Co ₃ O ₄ , CoO and Fe ₂ O ₃ added as an amount of 1 to 10% by weight based on the solid content; And

(d) organic vehicles.

In the present invention, Nb _x La _1-x B _6-4x in which x is 0.1 to 0.9 mol, preferably _0.2 to _0.8 mol is used as the resistive material a1. When x is smaller than 0.1 mole, it is difficult to gradually increase the area resistance, and when x is larger than 0.9 mole, the rate of change of area resistance according to the composition of the glass frit increases, thereby improving reproducibility of area resistance. it's difficult.

The particle size of the resistive material is generally 0.1-5 μm. If the particle size is smaller than 0.1 μm, the grinding time required for producing the resistive material is long, and impurities introduced during the crushing may adversely affect the properties of the resistive material.

When the particle size is larger than 5 µm, it is difficult to obtain a constant resistance by a stable method.

The resistive material can be prepared by conventional methods such as those described in US Pat. No. 5,036,027.

Examples of the non-reducing glass frit (a2) used in the present invention include alkaline earth borosilicate, boroaluminosilicate, and the like. The particle size of the non-reducing glass frit is generally 1-10 μm. If the particle size is smaller than 1 m, the change rate of the area resistance tends to be too large. If the particle size is larger than 10 m, it is difficult to obtain a uniform resistor in a stable manner. Non-reducing glass frits can be prepared by conventional methods such as mixing with a suitable oxide to melt.

The weight ratio of the resistive material (a1) to the non-reducing glass frit (a2) in the solid content (a) can be varied within a range depending on the desired area resistance, and in the present invention is 5/100 to 70/100 by weight ratio.

TiO _{2, which} is the first additive (b), is added to the solids containing the resistive material and glass frit in an amount of 1 to 10% by weight, preferably 2 to 7% by weight relative to the solids.

Further, as the second additive (c), at least one selected from the group consisting of Co ₃ O ₄ , CoO and Fe ₂ O ₃ is also in an amount of 1 to 10% by weight, preferably 2 to 5% by weight, based on the solid content. Amount is added to the solids. If the added amount of at least one of the first and second additives is less than 1% by weight, the resistor obtained will insufficiently move the TCR in the negative direction. If the added amount of at least one of the first and second additives exceeds 10% by weight, the resulting resistor will cause the TCR to move too much in the negative direction.

In the present invention, (1) a combination of 2 to 7% by weight (preferably 5% by weight) of TiO ₂ and ₂ to 5% by weight (preferably 5% by weight) of Co ₃ O ₄ ; Or (2) a combination of 2 to 7 wt% (preferably 5 wt%) of TiO ₂ and 1 to 3 wt% (preferably 3 wt%) of Fe ₂ O ₃ .

The organic carrier (d) is used to form the resistance paste according to the present invention. Examples include terpenes such as α-terpineol, β-terpineol, or these, kerosine, butyl carbitol, butyl carbitol acetate, and the like. Acrylic resin and ethyl cellulose diluted with mixture with other solvents, such as high boiling alcohol and alcohol ester, are mentioned. Such organic carriers must have thixotropy (thixotropy) in order to be quickly hardened after screening to obtain good resolution.

In the resistance paste of the present invention, the weight ratio of the organic carrier (d) to the total weight of solids (a) and additives (b) and (c) is 20/80 to 60/40, preferably 30/70 to 50/50. to be.

The resistance paste of the present invention can be produced by a conventional method for producing a resistance paste. For example, the resistance material and the glass frit are separately prepared, mixed with the first and second additives, and then the obtained mixture is kneaded together with the organic carrier to form a resistance paste according to the present invention.

The resist paste according to the invention can be used in a similar way as in conventional pastes. For example, the resist paste is printed on a suitable substrate such as a ceramic substrate by screen printing, dried for 10 minutes at 150 ° C., and then sintered for 10 minutes at a peak temperature of 900 ° C. in a nitrogen atmosphere. Are manufactured.

The area magnetic term of the resistor formed of the resistor paste according to the present invention is not particularly limited, but is usually 10 to 200 Ω / □, preferably 20 to 100 Ω / □.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. All percentages below refer to% by weight unless otherwise specified.

EXAMPLE

[Production of Electrode]

A conductive paste containing copper as a base metal was screen printed on an alumina ceramic substrate, and then sintered in a nitrogen atmosphere to form an electrode.

[Production of Resistance Paste]

As shown in Table 1 below, NbB ₂ and LaB ₆ powders were weighed and mixed in a Nb _x La _1-x B _{6-4x so} that x varies within a range of 0.1 to 0.9 moles. The resultant mixture was calcined in a nitrogen atmosphere at which the normal temperature was set to 1000 ° C. for 2 hours, at a temperature rising rate of 3 ° C./min, to form a solid solution of LaB ₆ in NbB ₂ . The resulting mixture is ground in a vibration mill to have an average particle size of 1 μm, and then dried to obtain a resistive material having a composition of Nb _x La _1-x B _6-4x (where x is 0.1 to 0.9 mol). Got it.

Separately, B ₂ O ₃ , SiO ₂ , BaO, CaO, Nb ₂ O _5, and K ₂ O were each mixed in a molar ratio of 35.56 / 31.24 / 17.79 / 10.04 / 2.41 / 2.97, and the resulting mixture was prepared at a temperature of 1,200 to 1,350 ° C. Melting at temperature gave fused glass. The molten glass was quenched in pure water and then pulverized in a vibrating mill to have an average particle size of about 5 μm to obtain a non-reducing glass frit.

The obtained mixture was kneaded together with an organic carrier made of acrylic resin diluted with α-terpineol to obtain a resist paste.

(week): 1: x in NbLaB

2: weight% for resistive material / glass frit

3: Sample outside the scope of the present invention

[Production of Resistor]

Each of the resist pastes in Table 1 was screen printed on alumina substrates with a length of 1.5 mm in length, 1.5 mm in width, and 20 μm in thickness (dry thickness), including the positive electrode, and then dried at 150 ° C. for 10 minutes. Subsequently, the normal temperature was 900 ° C., followed by sintering for 10 minutes in a nitrogen atmosphere to form a resistor.

[evaluation]

Area reduction and TCR of each sample were measured. The results are shown in Table 2.

(week) Samples outside the scope of the present invention

As shown in Table 2, Sample 1 (x = 0.50 moles) containing no first additive and only 5% CoO as second additive had a TCR of +478 ppm / ° C. at −55 ° C. and +150 For samples with a TCR of +468 ppm / ° C. while containing 1-10% TiO as the first additive and 5% CoO as the second additive, the TCR was negative compared to that of Sample 1. Moved in the direction of-).

Sample 5 containing 10% or more of the first additive (TiO) did not exhibit satisfactory properties as a resistor because TCR moved largely in the negative direction.

Sample 7, containing no second additive and containing only the first additive, had a TCR of +420 ppm / ° C. at −55 ° C. and a TCR of +367 ppm / ° C. at + 150 ° C., while in addition to the first additive. It can be seen that the samples containing 1 to 10% of the second additive selected from CoO, CoO and FeO have almost the same area resistance compared to Sample 7, while the TCR has moved in the negative direction. On the other hand, in the case of samples 11, 15 and 19 containing 10% or more of the second additive, the TCR moved too much in the negative direction and did not exhibit satisfactory properties as a resistor.

Similarly, sample 21 (x = 0.75 moles) containing no second additive and only the first additive showed a TCR of +355 ppm / ° C. at −55 ° C. and +341 ppm / ° C. at + 150 ° C. Samples containing 1 to 10% of a second additive selected from CoO, CoO and FeO in addition to the first additive have almost the same area resistance as that of Sample 21, while the TCR moves in the negative direction. It was. It should be noted that samples 25, 29 and 33 containing at least 10% of a second additive had too much TCR in the negative direction and did not show satisfactory properties as resistors.

Samples containing the first additive and a total of 6% of the second additive (samples 34,35,36,37) also had a TCR of +49 to +79 ppm / ° C at -55 ° C and + 150 ° C. Satisfactory properties such as having a TCR of +55 to +83 ppm / ° C.

In brief, adding the first and second additives to the NbLaB-based resist paste (x is 0.1 to 0.9 mol) causes the TCR to move in the negative direction with little change in the area resistance. It is effective to bring the TCR of the resistor formed of the resist paste close to 0. When the addition amount of either of the first and second additives exceeds 10%, the area resistance increases and the TCR is in the negative direction. Too much is moved.

In the NbLaB paste, when x is less than 0.1, the resistance is significantly decreased, and when it is larger than 0.9, the resistance is significantly increased. In both cases, this resistive material did not perform satisfactorily as a resistor at any mixing ratio with the glass frit.

As described above, the resist paste according to the present invention comprises a solid content of a resistive material having a composition of NbLaB (x is 0.1 to 0.9 mol) and a non-reducing glass frit; As a first additive, 1-10 weight% TiO with respect to an electrical solid content; As the second additive, at least one member selected from the group consisting of CoO, CoO and FeO contains 1 to 10% by weight based on the solid content. According to the present invention, in a resistor formed by sintering a NbLaB-based resistance paste, the resistance temperature coefficient of the area resistance can be moved in the negative direction in a region having a low area resistance, whereby the resistance paste of the present invention. The effect of sufficiently satisfying the properties required for the resist paste in sintering in a neutral or reducing atmosphere can be obtained.

While the invention has been described in detail with reference to the embodiments in particular, it is also possible for various changes and modifications without departing from the scope of this qf name, which is obvious to those skilled in the art.

Claims (4)

A resistive paste characterized by containing the following components: (a) a resistive material (a1) having a composition of Nb _x La _1-x B _6-4x (where x is 0.1 to 0.9 mol) and a non-reducing glass Solids containing frit (a2); (b) TiO ₂ added as an amount of 1-10 weight% with respect to the said solid content; (c) at least one member selected from the group consisting of Co ₃ O ₄ , CoO and Fe ₂ O ₃ added as an amount of 1 to 10% by weight based on the solid content; And (d) organic vehicles. The resistance paste of claim 1, wherein the amount of the first additive (b) is 2 to 7% by weight based on the solids, and the amount of the second additive (c) is 2 to 5% by weight based on the total weight of the solids. The method according to claim 2, wherein the first additive (b) is 2 to 7% by weight of TiO _{2 based} on the solids, and the second additive (c) is 2 to 5% by weight of Co ₃ O _{4 based} on the solids. Resistance paste made with. The method according to claim 2, wherein the first additive (b) is 2 to 7% by weight of TiO _{2 based} on the solids, and the second additive (c) is 1 to 3% by weight of Fe ₂ O _{3 based} on the solids. Resistance paste made with.