JP2006261243A - Resistor paste, resistor and electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain the temperature characteristics (TCR) and the withstand voltage characteristics (STOL) of resistance having small values certainly, and to improve noise characteristics. <P>SOLUTION: The resistor paste is produced by dispersing a conductive material, a glass composition, and an additive into an organic vehicle wherein the additive contains a composite oxide which contains Ti and at least one selected from Mg, Ca, Sr, Ba, and mean particle diameter of the composite oxide is 0.7 μm or less. Assuming the mean particle diameter of the composite oxide is T, and the mean particle diameter of the glass composition is G, following relation is satisfied; T≤G. Furthermore, following relation is preferably satisfied; T≤(G/2). Assuming the mean particle diameter of the conductive material is R, following relation is satisfied more preferably; T≤R≤(G/2). The composite oxide is represented by ATiO<SB>3</SB>(in the formula, A is at least one selected from Mg, Ca, Sr, and Ba). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resistor paste containing a conductive material, a glass composition and an additive, and further relates to a resistor and an electronic component formed using the resistor paste.

  For example, a resistor paste is generally composed of a glass composition for adjusting a resistance value and imparting bonding properties, a conductive material, and an organic vehicle as main components, and after printing this on a substrate, By baking, a resistor having a thickness of about 5 to 20 μm is formed. In this type of resistor paste (resistor), lead ruthenium oxide or the like is usually used as the conductive material, and lead oxide (PbO) glass or the like is used as the glass composition.

  By the way, in recent years, environmental problems have been actively discussed. For example, in solder materials, it is required to exclude lead. Resistor paste and resistor are no exception. Therefore, in consideration of the environment, it is possible to use lead ruthenium oxide as a conductive material as described above, or to use PbO-based glass as a glass composition. Must be avoided.

Under such circumstances, research on lead-free resistor pastes and thick film resistors has been conducted in various fields. For example, Patent Document 1 preferably contains, for example, CaTiO ₃ in an amount of more than 0 vol% and 13 vol% or less, or NiO in an amount of more than 0 vol% and no more than 12 vol%, and further additives such as CuO, ZnO, and MgO It is described that it is preferable to add the two at the same time, which is suitable for obtaining a resistor having a low resistance temperature characteristic (TCR) and withstand voltage characteristic (STOL) while having a high resistance value. It is described that it is possible to provide a lead-free resistor paste.
JP 2003-197405 A

  By the way, as a problem to be improved in the lead-free resistor, there is a deterioration in noise characteristics in addition to the above TCR and STOL. However, Patent Document 1 does not recognize the problem of the noise characteristics of the resistor, and naturally, no measures are taken to improve the noise value.

  Therefore, the present invention has been proposed in view of such a conventional situation, and the temperature characteristic (TCR) and the withstand voltage characteristic (STOL) of the resistance value are surely made small values, and the noise characteristic is improved. An object of the present invention is to provide a resistor paste that can be achieved. Another object of the present invention is to provide a resistor and an electronic component using the resistor paste.

  In order to achieve the above object, a resistor paste according to the present invention is a resistor paste in which a conductive material, a glass composition, and an additive are dispersed in an organic vehicle, and the additive includes Mg, It contains a composite oxide containing at least one selected from Ca, Sr, and Ba and Ti, and an average particle size of the composite oxide is 0.7 μm or less. Moreover, the resistor according to the present invention is formed using the resistor paste. Furthermore, an electronic component according to the present invention is characterized by having the resistor.

  In the present invention, as the additive contained in the resistor paste, a composite oxide having an average particle diameter of 0.7 μm or less and containing at least one selected from Mg, Ca, Sr, and Ba and Ti is used. By using such a fine composite oxide as an additive, noise characteristics can be improved while ensuring TCR characteristics and STOL characteristics.

  By using the resistor paste of the present invention, it is possible to form a resistor and an electronic component that are excellent in any of TCR, STOL, and noise characteristics while having a lead-free composition.

  Hereinafter, embodiments of a resistor paste, a resistor, and an electronic component to which the present invention is applied will be described in detail.

  The resistor paste of the present invention is a composite comprising at least one selected from Mg, Ca, Sr, and Ba, having an average particle size of 0.7 μm or less as a glass composition, a conductive material, and an additive. A resistor composition containing an oxide and composed of these components is mixed with an organic vehicle.

Here, the conductive material has a role of imparting conductivity to the resistor, which is a structure, by being dispersed in the glass composition that is an insulator. As the conductive material, a lead-free conductive material substantially containing lead is used. Specifically, a conductive material containing Ru, for example, RuO ₂ or a Ru composite oxide is used. As the Ru composite oxide, one or more selected from CaRuO ₃ , SrRuO ₃ , BaRuO ₃ , and Bi ₂ Ru ₂ O ₇ are preferable.

  The composition of the glass composition is not particularly limited, but in the present invention, it is preferable to use a lead-free glass composition that does not substantially contain lead for environmental protection. In the present invention, “substantially free of lead” means not containing lead exceeding the impurity level, and the amount of the impurity level (for example, the content in the glass composition or the conductive material is If it is about 0.05% by mass or less), it may be contained. Lead may be contained in a trace amount as an inevitable impurity.

  When the glass composition is a resistor, it has a role of binding the conductive material and the additive to the substrate in the resistor. As the glass composition, it is possible to use a material obtained by mixing a raw material modified oxide component, a network-forming oxide component, etc., and vitrifying it. In particular, as a main modified oxide component, an alkaline earth metal oxide is used. Specifically, so-called CaO-based glass using one or more selected from CaO, SrO, and BaO is preferable.

But with the other ingredients in the glass composition, as a network-forming oxide component may include B ₂ O ₃ and SiO _2.

In addition to the main modified oxide component, any other metal oxide can be used as another modified oxide component. Specific examples of the metal oxide include, for example, ZrO ₂ , Al ₂ O ₃ , ZnO, CuO, NiO, CoO, MnO, Cr ₂ O ₃ , V ₂ O ₅ , MgO, Li ₂ O, Na ₂ O, and K _2. Examples include O, TiO ₂ , SnO ₂ , Y ₂ O ₃ , Fe ₂ O ₃ , MnO ₂ , Mn ₃ O _4, Ta ₂ O ₅ , Nb ₂ O ₅ , Sc ₂ O ₃ , and In ₂ O _3. One or two or more selected from these may be used.

  Each component of the glass composition can be selected according to the resistance value of the resistor.

  In the present invention, a composite oxide containing at least one selected from Mg, Ca, Sr, and Ba and Ti (hereinafter simply referred to as Ti composite oxide) is used as an additive. A major feature is that the average particle size is 0.7 μm or less. By setting the average particle size of the Ti composite oxide within an appropriate range, noise characteristics can be improved in addition to TCR and STOL. The noise characteristic tends to be improved as the average particle size of the Ti composite oxide used is reduced, and TCR and STOL are also maintained. Accordingly, the average particle diameter of the Ti composite oxide may be a value exceeding 0, but the manufacture becomes more difficult as the Ti composite oxide is made finer. For example, 0.01 μm or more, preferably 0.02 μm or more. To do.

  A Ti composite oxide having an average particle size of 0.7 μm or less is produced by pulverizing a Ti composite oxide having a normal particle size. The average particle diameter of the Ti composite oxide can be measured, for example, by observation with an electron microscope.

  In order to further improve the noise characteristics, it is preferable to pay attention to the relationship between the average particle size of the Ti composite oxide contained in the resistor paste and the average particle size of the glass composition. Specifically, when the average particle size of the Ti composite oxide is T and the average particle size of the glass composition is G, the relationship of T ≦ G is satisfied. By setting the average particle size T of the Ti composite oxide to be equal to or less than the average particle size G of the glass composition, the solubility of the Ti composite oxide in the glass component is improved, and the noise characteristics are further improved. By setting the relationship between the average particle diameter T of the Ti composite oxide and the average particle diameter G of the glass composition to be T ≦ (G / 2), a higher noise characteristic improving effect is exhibited.

  In addition to the relationship between the average particle size T of the Ti composite oxide contained in the resistor paste and the average particle size G of the glass composition, attention should be paid to the relationship with the average particle size R of the conductive material. The noise characteristics of the resistor can be further improved. Specifically, the relationship of T ≦ R ≦ (G / 2) is satisfied.

The Ti composite oxide is not particularly limited as long as it is a composite oxide containing Ti and at least one selected from Mg, Ca, Sr, and Ba, as described above. For example, ATiO ₃ (wherein A is at least one selected from Mg, Ca, Sr, and Ba.). Further, the composite oxide is not limited to the composite oxide represented by the above formula. For example, A (Ti, Zr) O ₃ , A (Ti, Hf) in which a part of Ti in the composite oxide is substituted with Zr, Hf, or the like. O _{3 and the} like are also included in the Ti composite oxide of the present invention. Furthermore, for example, Mg ₂ TiO ₄ or the like can be used as the Ti composite oxide.

  The resistor paste preferably includes a metal material as an additive in addition to the Ti composite oxide. As the metal material, fine particles of any conductive metal such as Ag can be used, but Ag is most preferable from the viewpoint of combination with Ti composite oxide. By adding to the resistor paste in a combination of a Ti composite oxide and a metal material, the TCR of the formed resistor is remarkably flattened to ± 100 ppm or less. Moreover, about STOL, the value close | similar to zero (0.1% or less) is achieved in a wide composition range.

  The combined use of the Ti composite oxide and the metal material can sufficiently improve TCR and STOL without using other additives, but other additives are included as necessary. Also good. As an additive, an arbitrary metal oxide can be exemplified, but STOL can be further improved by using CuO in combination.

  The resistor composition described above is made into a resistor paste by being dispersed in an organic vehicle. However, any organic vehicle for resistor paste can be used for this type of resistor paste. Yes, for example, a binder resin such as ethyl cellulose, polyvinyl butyral, methacrylic resin, butyl methacrylate, and a solvent such as terpineol, butyl carbitol, butyl carbitol acetate, acetate, toluene, various alcohols, xylene may be used. it can. At this time, various dispersants, activators, plasticizers, and the like can be appropriately used in accordance with the application.

  Although it is the compounding ratio of the said organic vehicle, the ratio (W2 / W1) of the mass (W1) of a resistor composition and the mass (W2) of an organic vehicle is 0.25-4 (W2: W1 = 1: 0). .25 to 1: 4). More preferably, the ratio (W2 / W1) is 0.5-2. If the ratio is outside the above range, a resistor paste having a viscosity suitable for forming a resistor on, for example, a substrate may not be obtained.

In order to form the resistor, the resistor paste containing the above-described components may be printed (applied) on the substrate by a method such as screen printing and fired at a temperature of about 850 ° C. As the substrate, a dielectric substrate such as an Al ₂ O ₃ substrate or a BaTiO ₃ substrate, a low-temperature fired ceramic substrate, an AlN substrate, or the like can be used. The substrate form may be any of a single layer substrate, a composite substrate, and a multilayer substrate. In the case of a multilayer substrate, the resistor may be formed on the surface or inside. In the formed resistor, the composition of the resistor composition contained in the resistor paste is maintained almost as it is.

  In forming the resistor, a conductive pattern to be an electrode is usually formed on the substrate, and this conductive pattern is printed with a conductive paste containing an Ag-based highly conductive material containing Ag, Pt, Pd, or the like, for example. Can be formed. Further, a protective film (overglaze) such as a glass film may be formed on the surface of the formed resistor.

  The electronic component to which the resistor of the present invention can be applied is not particularly limited. For example, a single-layer or multi-layer circuit board, a resistor such as a chip resistor, an isolator element, a CR composite element, a module element, and a laminated layer Capacitors such as chip capacitors, inductors and the like can be mentioned, and the present invention can also be applied to electrode portions such as capacitors and inductors.

  Hereinafter, specific examples of the present invention will be described based on experimental results.

<Preparation of glass composition>
A predetermined amount of a compound such as B ₂ O ₃ , SiO ₂ , CaCO ₃ , SrCO ₃ , BaCO ₃ , ZrO ₂ , Ta ₂ O ₅ was weighed so as to have the composition shown in Table 1, mixed in a ball mill, and then dried. . The obtained powder was heated to 1300 ° C. at a rate of 5 ° C./min, held at that temperature for 1 hour, and then rapidly cooled by being put into water to be vitrified. The obtained vitrified product was pulverized with a ball mill to obtain a glass composition powder. The composition of the obtained glass powder is shown in Table 1 below.

<Conductive material, Ti composite oxide, additive>
As the conductive material, RuO ₂ , CaRuO ₃ , SrRuO ₃ , and BaRuO ₃ were used. Further, using _{BaTiO 3, SrTiO 3, CaTiO 3} , MgTiO 3 , etc. as Ti composite oxide. Furthermore, as an additive, Ag was used as a metal material, and CuO was used as another additive.

<Preparation of organic vehicle>
Using ethyl cellulose as the binder and terpineol as the organic solvent, the binder was dissolved while heating and stirring the organic solvent to prepare an organic vehicle.

<Preparation of resistor paste>
The conductive material, the glass composition powder, the Ti composite oxide, the additive, and the organic vehicle were weighed so as to have each composition, and kneaded with a three-roll mill to obtain a resistor paste. The ratio of the total mass of the conductive material, glass composition powder, Ti composite oxide and additive to the mass of the organic vehicle is such that the obtained resistor paste has a viscosity suitable for screen printing. In the range of 1: 0.25 to 1: 4, a resistor paste was prepared.

<Fabrication of resistor>
On a 96% alumina substrate, the Ag—Pt conductor paste was screen-printed in a predetermined shape and dried. The Ag ratio in the Ag-Pt conductor paste was 95% by mass, and the Pt ratio was 5% by mass. This alumina substrate was placed in a belt furnace and baked in a pattern of 1 hour from charging to discharging. The baking temperature at this time was 850 ° C., and the holding time at that temperature was 10 minutes.

  On the alumina substrate on which the conductor was formed in this manner, the resistor paste prepared previously was applied in a pattern of a predetermined shape (1 mm × 1 mm square shape) by screen printing and dried. Thereafter, the resistor paste was baked under the same conditions as the conductor baking to obtain a resistor.

<Evaluation of resistor characteristics>
(1) Resistance value
Measurement was performed with Agilent Technologies product number 34401A. The average value of 24 samples was determined.

(2) TCR
The resistance value change rate when the temperature was changed to −55 ° C. and 125 ° C. was obtained based on the room temperature of 25 ° C. The average value of 10 samples. When resistance values of −55 ° C., 25 ° C., and 125 ° C. are R-55, R25, and R125 (Ω / □), CTCR and HTCR are expressed as follows.
CTCR (ppm / ° C) = [(R-55-R25) / R25 / 80] x 1000000
HTCR (ppm / ° C) = [(R125-R25) / R25 / 100] x 1000000
Of CTCR and HTCR, the larger absolute value was taken as the TCR value. TCR ≦ ± 100 ppm is a standard for characteristics.

(3) STOL (short-time overload)
A test voltage was applied to the resistor for 5 seconds, and the change rate of the resistance value before and after that was determined. The average value of 10 samples. Test voltage = 2.5 × rated voltage, rated voltage = √ (R / 4), and R is a resistance value (Ω / □). For a resistor having a resistance value with a calculated test voltage exceeding 400V, the test voltage was 400V.

(4) Noise characteristics
It was measured by a trade name model 315c manufactured by Quan-Tech. The average value of 10 samples was determined. At a level of 500 kΩ to 1 MΩ, 15 dB or less is a characteristic reference. In general, the noise value tends to increase as the resistance value increases.

<Examination of Ti composite oxide>
In the preparation of the resistor paste, with a glass composition powder 1, CrRuO _3, BaTiO _3, etc. as Ti composite oxide, Ag, selected from CuO used as additives, the description of the fabrication of the section of the resistor Thus, resistors of Sample 1 to Sample 18 were prepared. Table 2 shows the average particle sizes of the conductive material, glass composition and Ti composite oxide used. Table 2 shows the composition of the resistor composition in each sample and the results of the characteristic evaluation. In the following table, the same applies, but the particle size in the table is the average particle size, and its unit is μm. Moreover, in each table | surface, * mark was attached | subjected to the sample etc. (equivalent to a comparative example) remove | deviating from the range prescribed | regulated by this invention.

  First, the average particle size of the Ti composite oxide will be examined. As shown in Table 2, in sample 1 and sample 5 in which the average particle size of the Ti composite oxide exceeds 0.7 μm, the noise value is significantly higher than 15 dB or less. In contrast, Samples 2 to 4 and Samples 6 to 8 in which the average particle size of the Ti composite oxide is appropriately set achieves TCR ± 100 ppm or less and STOL 0.1% or less, and also has a good noise value. The value is shown. Moreover, the sample whose average particle diameter T of Ti composite oxide is below the average particle diameter G of a glass composition compared with the sample 6 whose average particle diameter T of Ti composite oxide exceeds the average particle diameter G of a glass composition 2 to Sample 4, Sample 7 and Sample 8 have improved noise characteristics, and Sample 3, Sample 4 and Sample 8 satisfying the relationship of T ≦ (G / 2) have obtained better results. Furthermore, considering the relationship with the average particle diameter R of the conductive material, the noise value becomes almost zero by satisfying the relationship of T ≦ R ≦ (G / 2).

Further, from Sample 9 to Sample 18, Ti composite oxides such as SrTiO ₃ , CaTiO ₃ , MgTiO ₃ , (Ba, Ca) TiO ₃ , (Ba, Mg) TiO ₃ , Ba (Ti, Zr) O ₃ , (Ba , Sr) (Ti, Hf) O ₃ also showed the same results as when BaTiO ₃ was used.

<Examination of conductive materials, glass compositions and additives>
In preparing the resistor paste, the components shown in Table 3 below were selected and used, and Sample 19 to Sample 33 were prepared in accordance with the description in the section of resistor production. Table 3 shows the composition of the resistor composition in each of these samples and the results of characteristic evaluation.

In Table 3, when RuO ₂ , SrRuO ₃ , and BaRuO ₃ are used as conductive materials from Sample 19 to Sample 24, Ti having an average particle size T of 0.7 μm or less is the same as in the case of using CaRuO _3. By using the composite oxide, a significant improvement in noise characteristics is realized. Further, when the modified oxide component in the composition is changed from the sample 25 to the sample 31 (glass composition powder 2 to glass composition powder 4), the average particle diameter T of the Ti composite oxide is 0.7 μm. A favorable noise characteristic was acquired by setting it as follows. Furthermore, from the sample 32 and the sample 33, it was confirmed that the present invention is also effective when the resistor paste does not contain CuO as a metal material or other additive.

Claims (7)

A resistor paste in which a conductive material, a glass composition and an additive are dispersed in an organic vehicle,
A resistance comprising a composite oxide containing Ti and at least one selected from Mg, Ca, Sr, and Ba as the additive, wherein the composite oxide has an average particle size of 0.7 μm or less. Body paste.   2. The resistor paste according to claim 1, wherein a relation of T ≦ G is satisfied, where T is an average particle diameter of the composite oxide and G is an average particle diameter of the glass composition.   3. The resistor paste according to claim 2, wherein a relationship of T ≦ (G / 2) is satisfied.   The resistor paste according to claim 3, wherein when the average particle diameter of the conductive material is R, a relationship of T ≦ R ≦ (G / 2) is satisfied. 5. The composite oxide according to claim 1, wherein the composite oxide is represented by ATiO ₃ (wherein A is at least one selected from Mg, Ca, Sr, and Ba). Resistor paste.   A resistor formed using the resistor paste according to any one of claims 1 to 5.   An electronic component comprising the resistor according to claim 6.