JP2018014211A - Resistance paste and resistive element prepared from the resistance paste - Google Patents

Abstract

A lead-free thick-film resistor having a high resistance value and good electrical characteristics with small current noise and an inexpensive lead-free resistor paste as a material thereof are provided. SOLUTION: A resistor paste substantially composed of conductive particles made of a lead-free oxide containing ruthenium, a lead-free glass frit, an organic vehicle, and an additive, wherein the additive is At least one of tin oxide, hafnium oxide and indium oxide is contained in a total amount of 0.2% by mass or more and 7.0% by mass or less. [Selection figure] None

Description

  The present invention relates to a resistor paste used as a material for resistors such as thick film chip resistors and hybrid ICs, and more particularly to a resistor paste containing no lead, and a resistor produced by firing the paste.

  As a method for forming a resistor film of an electronic component, a thick film method for forming a film using a resistance paste containing a film forming material and a thin film method for forming a film by sputtering the film forming material are generally known. ing. Among them, the thick film method is to form a resistor by printing a resistor paste on a ceramic substrate and then firing it. This method is inexpensive and has high productivity required for film formation. It is widely used for manufacturing resistors included in electronic components such as chip resistors and hybrid ICs.

The resistive paste used in the thick film system is substantially composed of conductive particles and glass frit, and an organic vehicle for making them suitable for printing. As the conductive particles, ruthenium dioxide (RuO ₂ ) or pyrochlore-type ruthenium-based oxides (Pb ₂ Ru ₂ O ₇ -X, Bi ₂ Ru ₂ O ₇ ) are generally used. The reason why the Ru-based oxide is used as the conductive particles is mainly because the resistance value changes gently with respect to the concentration of the conductive particles.

In addition, as a glass frit, a large amount of lead such as lead borosilicate glass (PbO—SiO ₂ —B ₂ O ₃ ) and lead aluminoborosilicate glass (PbO—SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ ) is used. Including lead borosilicate glass. The reason why the lead borosilicate glass is used for the glass frit in this way is that it has good wettability with the Ru-based oxide, has a thermal expansion coefficient close to that of the substrate, and has a suitable viscosity during firing.

In the above-described resistance paste, various additives have been included for a long time in order to improve the characteristics of the resistor after film formation. For example, Patent Document 1 discloses a technique of containing titanium oxide (TiO ₂ ) for improving withstand voltage characteristics. Patent Document 2 discloses a technique for containing niobium oxide (Nb ₂ O ₅ ) or the like in order to reduce the change in resistance temperature coefficient.

  Furthermore, recently, in order to protect the environment, lead-free electronic components have been developed, and lead-free solder pastes have also been proposed. For example, Patent Document 3 discloses a technique of using iridium dioxide for conductive particles in order to suppress noise while realizing high resistance without lead.

JP-A-61-206201 Japanese Patent Publication No. 63-35081 JP 2006-294589 A

In recent years, electronic components and the like manufactured using the above-described resistance paste as a material tend to be smaller and have higher performance. Therefore, the resistance paste has a low resistance temperature coefficient while having a high resistance value, and What can produce a resistor with low current noise is desired. However, when TiO ₂ or Nb ₂ O ₅ as described above is used as an additive, although the characteristics can be improved with a small addition amount, the resistance temperature coefficient also changes greatly, so the resistance temperature coefficient is reduced. There is a problem that is difficult.

  In addition, as described in Patent Document 1 and Patent Document 2, most conventional resistor pastes contain lead, and when the resistor paste is made lead-free, it is expensive as in Patent Document 3. The use of new iridium has been performed. The present invention has been made in view of the above-described conventional problems, a lead-free thick film resistor excellent in electrical characteristics capable of suppressing current noise to a small value while having a high resistance value, and the same An object is to provide an inexpensive lead-free resistance paste as a material.

  As a result of repeated studies on a lead-free resistance paste capable of achieving the above object, the present inventor uses a lead-free oxide containing ruthenium in conductive particles by including a specific additive in the resistance paste. At the same time, it has been found that a resistor having good electrical characteristics can be formed even when a glass frit containing no lead is used, and the present invention has been completed.

  That is, the resistance paste provided by the present invention is a resistance paste substantially composed of conductive particles made of a lead-free oxide containing ruthenium, a lead-free glass frit, and an organic vehicle, It is characterized by containing at least one of tin oxide, hafnium oxide and indium oxide as an additive in a total amount of 0.2% by mass or more and 7.0% by mass or less.

  According to the present invention, it is possible to inexpensively form a thick film resistor having excellent electrical characteristics that can suppress current noise while keeping a high resistance value without causing environmental pollution due to lead.

  Hereinafter, embodiments of the resistance paste of the present invention will be described. The resistive paste according to the embodiment of the present invention is substantially composed of conductive particles made of a lead-free oxide containing ruthenium, a lead-free glass frit, and an organic vehicle. Among these, the oxide is not particularly limited as long as it has conductivity, and oxides obtained by various production methods can be used. However, in order to prevent variation in the resistance value of the thick film resistor formed by firing and deterioration of current noise, it is desirable to make the conductive path in the thick film resistor fine. It is desirable that the average particle diameter of the BET diameter is 1.0 μm or less.

  If the glass frit which comprises the said resistance paste does not contain lead, there will be no restriction | limiting in particular in the composition. For example, borosilicate glass, aluminoborosilicate glass, borosilicate alkaline earth glass, borosilicate alkali glass, borosilicate zinc glass, borosilicate bismuth glass, or the like can be used. As described above, in order to prevent variation in resistance value of the thick film resistor and deterioration of current noise, it is desirable to make the conductive path in the thick film resistor fine. It is preferable that D50 (median diameter) by distribution measurement is 5 μm or less.

  The organic vehicle constituting the resistance paste may be one normally used for the resistance paste, for example, a resin obtained by dissolving a resin such as ethyl cellulose, butyral, or acrylic in a solvent such as terpineol or butyl carbitol acetate. Used for.

The resistance paste further includes at least one of tin oxide (SnO ₂ ), hafnium oxide (HfO ₂ ) and indium oxide (In ₂ O ₃ ) as an additive in a total amount of 0.2% by mass or more and 7.0% by mass. Contains the following. These additives serve to increase the resistance value of the resistor formed by firing and reduce current noise. The reason why the total content of the additives is set to 0.2% by mass or more with respect to the resistance paste is that if the content is less than 0.2% by mass, the effect of reducing current noise cannot be obtained sufficiently. Conversely, if the total content of the additives is 7.0% by mass or less, if the content exceeds 7.0% by mass, the resistance value becomes too high, and the effect of reducing the current noise cannot be obtained sufficiently. This is because the temperature coefficient of resistance may become too large.

  There is no restriction | limiting in particular in the manufacturing method of the resistance paste of embodiment mentioned above, It can produce by charging and knead | mixing the component of resistance paste mentioned above to commercially available kneading apparatuses, such as a roll mill. At that time, the mixing ratio of the conductive particles and the glass frit is preferably about 5/95 to 50/50 in terms of the ratio of the conductive particles / glass frit on a mass basis. Further, the method for manufacturing the resistor is not particularly limited, and the resistor can be formed by the same method as the conventional one using the resistor paste of the embodiment of the present invention as a material. For example, the above-described resistance paste is applied to a normal substrate such as an alumina substrate by screen printing or the like, dried, and then fired at a peak temperature of about 800 to 900 ° C. using a belt furnace or the like, thereby lead-free. Can be formed.

  As described above, since the resistive paste of the embodiment of the present invention does not contain lead, it does not cause environmental pollution like conventional resistive pastes and resistors containing lead, and does not contain expensive iridium. Therefore, the cost can be suppressed. A resistor formed by using this resistance paste as a material has good electrical characteristics similar to those of the conventional one, and in particular, there is little variation in resistance value, and noise can be kept small. it can. In addition to the above-described additives such as tin oxide, the resistor paste according to the embodiment of the present invention is conventionally used for adjusting the electrical characteristics of the thick film resistor, for example, a dispersing agent or a plasticizer. You may add various additives, such as, as needed.

Resistance value for thick film resistors prepared by mixing conductive particles, glass frit, organic vehicle, and additives at various blending ratios to prepare multiple resistance paste samples and firing them individually. Etc. were evaluated. Specifically, RuO ₂ powder having a BET diameter of 40 nm prepared by roasting ruthenium hydroxide was used as the conductive particles. For glass frit, 10 mass% SrO-43 mass% SiO ₂ -16 mass% B ₂ O ₃ -4 mass% Al ₂ O ₃ -20 mass produced by mixing, melting, quenching, and pulverizing by a general method. A glass frit having a composition of% ZnO-7 mass% Na ₂ O and having a D50 of 1.9 μm as measured by laser diffraction particle size distribution was used. SnO ₂ , HfO ₂ , In ₂ O ₃ , and TiO ₂ were prepared as additives, and the organic vehicle used was composed mainly of ethyl cellulose and terpineol. These RuO ₂ powder, glass frit, additive, and organic vehicle were weighed so as to have various blending ratios and kneaded by a three-roll mill. As a result, resistance pastes of Samples 1 to 16 having the compositions shown in Table 1 below were produced.

  Next, an alumina substrate on which two electrodes having an interelectrode distance of 1 mm are formed using AgPd paste is prepared for the resistance paste of each sample, and the two electrodes are connected on the alumina substrate. Was screen printed to a width of 1 mm, dried at 150 ° C. for 10 minutes, and then fired in a belt furnace at a peak temperature of 850 ° C. for 9 minutes. The electrical characteristics (resistance value, current noise) of the thick film resistor thus manufactured were measured, and the resistance temperature coefficient was calculated using the resistance value. The results are shown in Table 2 below.

The resistance value was measured by a four-terminal method using a Model 2001 Multimeter manufactured by KEITHLEY, and the current noise was measured by applying 1/10 W using a noise meter Model 315C manufactured by Quan-Tech. Table 2 lists the resistance values at 25 ° C. In addition, the resistance values at 125 ° C. and −55 ° C. were also measured, and the high temperature resistance temperature coefficient (HTCR) [ppm / ° C] and low temperature resistance temperature coefficient (CTCR) [ppm / ° C], respectively. Here, R ₂₅ is a resistance value at 25 ° C., R ₁₂₅ is a resistance value at 125 ° C., and R ₋₅₅ is a resistance value at −55 ° C.

[Formula 1]
HTCR = [(R ₁₂₅ -R ₂₅ ) / R ₂₅ (125-25)] × 10 ⁶
[Formula 2]
CTCR = [(R ₋₅₅ −R ₂₅ ) / R ₂₅ (−55−25)] × 10 ⁶

From the results of Table 2 above, the resistance pastes of Samples 1 to 13 of the present invention containing SnO ₂ , HfO ₂ , and In ₂ O ₃ as additives are inexpensive RuO ₂ conductive particles and lead-free glass. It can be seen that even when a thick film resistor having a high resistance value is formed using a frit, the resistance temperature coefficient can be reduced and the current noise can be reduced.

On the other hand, the resistance pastes of Samples 14 and 16 that do not add any of SnO ₂ , HfO ₂ , and InO ₃ as additives, or contain conventionally used TiO ₂ as additives, When a thick film resistor having a high resistance value is formed using conductive particles of RuO ₂ and glass frit as in Samples 1 to 13 of the present invention, current noise or resistance temperature coefficient cannot be sufficiently reduced. I understand. The resistance paste sample 15 the content of SnO ₂ exceeds the requirements of the present invention, it can be seen that the resistance temperature coefficient than that of any of the samples 1 to 13 is high.

Claims (4)

  A resistive paste substantially composed of conductive particles made of a lead-free oxide containing ruthenium, a lead-free glass frit, an organic vehicle, and an additive, wherein the additive includes tin oxide, oxide A resistance paste characterized by containing at least one of hafnium and indium oxide in a total amount of 0.2% by mass or more and 7.0% by mass or less.   It forms by baking the resistance paste of Claim 1, The lead-free resistor characterized by the above-mentioned.   An electronic component comprising the resistor according to claim 2. A method for producing a lead-free resistor, comprising producing a resistor by firing the resistor paste according to claim 1.