Thick film resistor paste, thick film resistor, and electronic component

Abstract

To provide a thick film resistor paste for a resistor having a smaller resistance change rate and excellent surge resistance, a thick film resistor using the thick film resistor paste, and an electronic component provided with the thick film resistor. A thick film resistor paste comprises an organic vehicle and a conductive substance-containing glass powder comprising ruthenium oxide and lead ruthenate, the conductive substance-containing glass powder comprises 10 to 70 mass % of conductive substances, a glass composition of the conductive substance-containing glass powder comprises 3 to 30 mass % of silicon oxide. 30 to 90 mass % of lead oxide, 5 to 50 mass % of boron oxide relative to 100 mass % of glass components, and, a combined amount of silicon oxide, lead oxide and boron oxide by mass % is 50 mass % or more relative to 100 mass % of the glass components.

Claims

1. A thick film resistor paste, characterized by comprising: an organic vehicle; and a conductive substance-containing glass powder comprising ruthenium oxide and lead ruthenate, wherein the conductive substance-containing glass powder comprises 10 mass % or more and 70 mass % or less of the conductive substances; wherein a glass composition of the conductive substance-containing glass powder comprises 3 mass % or more and 60 mass % or less of silicon oxide, 30 mass % or more and 90 mass % or less of lead oxide, and 5 mass % or more and 50 mass % or less of boron oxide relative to 100 mass % of glass components; and wherein a combined amount of silicon oxide, lead oxide and boron oxide by mass % is 50 mass %0 or more relative to 100 mass % of the glass components.

2. The thick film resistor paste according to claim 1, wherein an average particle diameter of the conductive substance-containing glass powder is 5 micrometers or less.

3. The thick film resistor comprising a sintered body of the thick film resistor paste according to claim 1.

4. An electronic component provided with the thick film resistor according to claim 3.

Description

EMBODIED EXAMPLES

(1) Hereinafter, the present invention will be explained more detail with reference to embodied examples, but the present invention is not limited to these examples.

Embodied Example 1: Evaluation of Resistor Having Area Resistance Value 1 Kiloohm

(2) The conductive substance-containing glass was prepared by mixing at a ratio of 48 mass % of a glass material, 2 mass % of ruthenium oxide, and 50 mass % of lead ruthenate, melting and then cooling the mixture. The glass composition of the prepared conductive substance-containing glass was 33 mass % of SiO.sub.2, 46 mass % of PbO, 5 mass % of Al.sub.2O.sub.3, 7 mass % of B.sub.2O.sub.3, 3 mass % of ZnO, and 6 mass % of CaO, relative to 100 mass % of glass components.

(3) The obtained conductive substance-containing glass was pulverized with a ball mill so that the average particle diameter was about 1 micrometer. The thick film resistor paste of Embodied Example 1 was prepared by mixing the following thick film resistor composition in a three-roll mill so that the various inorganic materials were dispersed in the organic vehicle. The thick film resistor composition contained 59 mass % of the conductive substance-containing glass powder, 1 mass % of Nb.sub.2C.sub.5 as an additive and the rest was comprised of the organic vehicle. For the organic vehicle, 20 mass parts of ethyl cellulose dissolved relative to 100 mass parts of turpineol was used. The composition of the thick film resistor paste of Embodied Example 1 and the composition of the conductive substance-containing glass used to produce the thick film resistor paste are shown in Table 1.

(4) <Evaluation Test>

(5) (Preparing of the Samples for Evaluation)

(6) The prepared thick film resistor paste was printed at a width of 1.0 mm between five pairs of electrodes at an interval of 1.0 mm spacing, the electrodes being preliminarily formed on an alumina substrate, and dried in a belt furnace at a peak temperature of 150 degrees Celsius for five minutes. Then, the thick film resistor paste was sintered in a belt furnace at a peak temperature of 850 degrees Celsius for nine minutes. Five similarly processed samples were made in each of five units of alumina substrates to obtain 25 thick film resistors as evaluation samples.

(7) (Film Thickness Measurement)

(8) Regarding film thickness, after selecting an arbitrary alumina substrate unit among the evaluation samples, a stylus-type surface roughness meter was used to measure the film thicknesses of each of the five thick film resistors, and the average value of the measured film thicknesses at the five points was used as an actual measured film thickness.

(9) (Converted Area Resistance)

(10) Resistance values of 25 evaluation samples formed on five alumina substrates at 25 degrees Celsius, were measured with a circuit meter (2001 MULTIMETER KEITHLEY Inc.), and the average value was used as the actual measured resistance. The following equation (1) was used to calculate the converted area resistance when the film thickness was 7 micrometers. The calculated converted area resistance is shown in Table 3.
Converted area resistance (kiloohm)=Measured resistance (kiloohm)?(Measured film thickness (micrometer)/7 (micrometer))(1)
(Temperature Coefficient of High Temperature Resistance: High Temperature TCR)

(11) The resistance values of the five thick film resistors of the evaluation samples formed on one alumina substrate, were measured while holding in thermostatic chambers at 25 degrees Celsius and at 125 degrees Celsius for 30 minutes, respectively. The measured resistance values were set to R.sub.25 and R.sub.125, respectively. And the high temperature TCR was calculated using the following equation (2). The calculated average value of high temperature TCRs of the five points is shown in Table 3.
High temperature TCR (ppm/degrees Celsius)=[(R.sub.125?R.sub.25)/R.sub.25]/(100)?10.sup.6(2)
(Evaluation of Trimming Property)

(12) A glass paste was prepared by kneading with a three-roll mill so as to disperse a glass material containing 30 mass % of SiO.sub.2, 55 mass % of PbO, 5 mass % of Al.sub.2O.sub.3, and 10 mass % of B.sub.2O.sub.3, in an organic vehicle of the same composition as that used in Embodied Example 1. The glass paste was applied to cover the thick film resistor of the evaluation sample and dried in a belt furnace at a peak temperature of 150 degrees Celsius for five minutes. The glass material was then sintered in a belt furnace at a peak temperature of 600 degrees Celsius for five minutes. The resistance value of the thick film resistor coated with the glass paste was set as the initial resistance value Rs(t), and then laser trimmed with a laser trimming device (SL432R, OMRON Laserfront, Inc.) so as to achieve a resistance value 1.5 times that of Rs(t). Laser trimming conditions were as follows: straight cut, cutting speed 100 mm/sec, laser intensity 2 W, and Q-rate of 6 kHz. The resistance value after trimming was set as Re(t), and the percentage of resistance value deviation before and after trimming was calculated using the following equation (3).
Resistance value deviation (%)=(Re(t)?1.5?Rs(t))/Rs(t)?100(3)

(13) If the resistance value deviation of any one of the five thick film resistors was 1% or more, the evaluation of trimming property was set to X, and if all the resistance value deviations were less than 1%, the evaluation was set to O. The evaluation results are shown in Table 3.

(14) (Evaluation of Surge Resistance: Resistance Value Change Rate)

(15) If the evaluation of trimming property was O, an electrostatic discharge test was conducted on the thick film resistor of the evaluation sample by applying a voltage under the condition of an electric capacity of 200 pF and an internal resistance of zero ohm, using a semiconductor device electrostatic tester (ESS-6008, Noise Research Labs). A voltage of 5 kV was applied to the thick film resistor of the evaluation sample five times at one-second intervals, and the resistance value before the voltage application Rs and the resistance value after the voltage application Re were measured. Resistance value change rates were calculated using the following equation (4). The calculated average value of the resistance value change rates at five points is shown in Table 3.
Resistance value change rate (%)=(Re?Rs)/Rs?100(4)

Embodied Examples 2-12

(16) Glass materials, ruthenium oxide, and lead ruthenate were mixed and melted in the proportions shown in Table 1, respectively, and then cooled to produce conductive substance-containing glass. The glass compositions of each of the manufactured conductive substance-containing glasses comprise SiO.sub.2, PbO, Al.sub.2O.sub.3, B.sub.2O.sub.3, ZnO, and CaO, wherein the proportions of each content relative to 100 mass % of the glass components are shown in Table 1.

(17) Each of the obtained conductive substance-containing glasses was pulverized with a ball mill to obtain the average particle diameter shown in Table 1. Each of thick film resistor pastes of Embodied Examples 2 to 12 was prepared by mixing the thick film resistor composition that contained the conductive substance-containing glass powder, the additives, and the organic vehicle in the proportions shown in Table 1, in a three-roll mill so that the various inorganic materials were dispersed in the organic vehicle. Each of the organic vehicles used in Embodied Examples 2 to 12 was the same composition as used in Embodied Example 1.

(18) Thick film resistors of the evaluation samples were also prepared in the same manner as in Embodied Example 1, and evaluated in the same manner as in Embodied Example 1. The results of each evaluation are shown in Table 3.

Comparative Example 1

(19) A thick film resistor paste was prepared by the conventional manufacturing method in which conductive substances and glass were added in respective powder form, without using a conductive substance-containing glass. However, if a ruthenium oxide powder, a lead ruthenate powder, and a glass powder were respectively added without using a conductive substance-containing glass powder that was obtained by grinding the conductive substance-containing glass, differences in electrical characteristics (TCR) or the like were occurred, in adjusting the resistance value suitable for the thick film resistor paste. Therefore, in Comparative Example 1 prepared by the conventional manufacturing method, to adjust TCR or the like, combination amounts of the ruthenium oxide powder and the lead ruthenate powder that were added as conductive substances, and combination amounts of the glass composition were adjusted. Namely, the thick film resistor composition comprising 6 mass % of ruthenium oxide powder, 17 mass % of lead ruthenate powder, 36 mass % of glass powder, 1 mass % of Nb.sub.2O.sub.5 as an additive and the rest comprising organic vehicle were mixed to make the thick film resistor paste of Comparative Example 1 in a three-roll mill so that the various inorganic materials were dispersed in the organic vehicle. The glass composition in the prepared thick film resistor paste was, 33 mass % of SiO.sub.2, 47 mass % of PbO, 5 mass % of Al.sub.2O.sub.3, 7 mass % of B.sub.2O.sub.3, 3 mass % of ZnO, and 5 mass % of CaO, relative to 100 mass % of the glass components. The organic vehicle used in Comparative Example 1 was the same composition as used in Embodied Example 1. The composition of the thick film resistor paste in Comparative Example 1 and the composition of the glass used to manufacture the thick film resistor paste are shown in Table 2.

(20) Thick film resistors of the evaluation samples were also prepared in the same manner as in Embodied Example 1, and evaluated in the same manner as in Embodied Example 1. The results of each evaluation are shown in Table 3.

Comparative Example 2

(21) A conductive substance-containing glass was manufactured by mixing at a ratio of 70 mass % of glass, 5 mass % of ruthenium oxide, and 25 mass % of lead ruthenate, melting and then cooling the mixture. The glass composition of the prepared conductive substance-containing glass was 30 mass % of SiO.sub.2, 65 mass % of PbO, 2 mass % of Al.sub.2O.sub.3, and 3 mass % of B.sub.2O.sub.3, relative to 100 mass % of the glass components.

(22) The obtained conductive substance-containing glass was pulverized with a ball mill so that the average particle diameter was about 1 micrometer. The thick film resistor paste of Comparative Example 2 was prepared by mixing the thick film resistor composition that contained 69 mass % of conductive substance-containing glass powder, 2 mass % of Mn.sub.2O.sub.3 as an additive and the rest comprising organic vehicle, in a three-roll mill so that the various inorganic materials were dispersed in the organic vehicle. The organic vehicle used in Comparative Example 2 was the same composition as used in Embodied Example 1.

(23) Thick film resistors of the evaluation samples were also prepared in the same manner as in Embodied Example 1, and evaluated in the same manner as in Embodied Example 1. The results of each evaluation are shown in Table 3.

Comparative Examples 3-10

(24) Glass materials, ruthenium oxide, and lead ruthenate were mixed and melted in the proportions shown in Table 1, respectively, and then cooled to produce conductive substance-containing glass. The glass compositions of each of the prepared conductive substance-containing glasses comprise SiO.sub.2, PbO, Al.sub.2O.sub.3, B.sub.2O.sub.3, ZnO, and CaO, wherein the proportions of each content relative to 100 mass % of the glass components are shown in Table 1.

(25) Each of the obtained conductive substance-containing glasses was pulverized with a ball mill so as to obtain the average particle diameter shown in Table 1. Each of the thick film resistor pastes of Comparative Examples 3 to 10 was prepared by mixing the thick film resistor composition that contained the conductive substance-containing glass powder, the additives, and the organic vehicle in the proportions shown in Table 1, in a three-roll mill so that the various inorganic materials were dispersed in the organic vehicle. Each of the organic vehicles used in Comparative Examples 3 to 10 was the same composition as used in Embodied Example 1.

(26) Thick film resistors of the evaluation samples were also prepared in the same manner as in Embodied Example 1, and evaluated in the same manner as in Embodied Example 1. The results of each evaluation are shown in Table 3.

(27) TABLE-US-00001 TABLE 1 Composition of thick film resistor paste Composition of conductive Content substance-containing glass amount of Conductive substances conductive Other additives Content Enbodied substance- Content Content Content Content amount Content Examples containing amount of amount of amount of amount of of lead amount of and glass organic niobium manganese ruthenium ruthenate conductive Comparative powder vehicle oxide oxide oxide oxide substances Examples (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) Embodied 59 40 1 2 50 52 Example 1 Embodied 59 40 1 0.4 9.6 10 Example 2 Embodied 59 40 1 2.7 67.3 70 Example 3 Embodied 59 40 1 2 50 52 Example 4 Embodied 59 40 1 2 50 52 Example 5 Embodied 59 40 1 2 50 52 Example 6 Embodied 59 40 1 2 50 52 Example 7 Enbodied 59 40 1 2 50 52 Example 8 Embodied 59 40 1 2 50 52 Example 9 Embodied 59 40 1 2 50 52 Example 10 Embodied 59 40 1 2 50 52 Example 11 Embodied 59 40 1 2 50 52 Example 12 Comparative 40 1 Example 1 Comparative 69 29 2 5 25 30 Example 2 Comparative 59 40 1 0.2 4.8 5 Example 3 Comparative 59 40 1 2.9 72.1 75 Example 4 Comparative 59 40 1 2 50 52 Example 5 Comparative 59 40 1 2 50 52 Example 6 Comparative 59 40 1 2 50 52 Example 7 Comparative 59 40 1 2 50 52 Example 8 Comparative 59 40 1 2 50 52 Example 9 Comparative 59 40 1 2 50 52 Example 10 Composition of conductive substance-containing glass Average Glass components particle Essential glass components diameter Combined Other glass components of the Content amount Context conductive Enbodied Content amount of these Content Content Amount substance- Examples amount of Content of essential amount amount of containing and silicon of lead boron glass aluminium of zinc calcium glass Comparative oxide oxide oxide components oxide oxide oxide powder Examples (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (micrometer) Embodied 33 46 7 86 5 3 6 1 Example 1 Embodied 33 46 7 86 5 3 6 1 Example 2 Embodied 33 46 7 86 5 3 6 1 Example 3 Embodied 3 66.6 10.1 79.7 7.3 4.3 8.7 1 Example 4 Embodied 60 30 5 95 1.8 1.2 2 1 Example 5 Embodied 42.8 30 9.1 81.9 6.5 3.8 7.8 1 Example 6 Embodied 4 90 5 99 0.4 0.2 0.4 1 Example 7 Enbodied 33.7 47 5 85.7 5.1 3.1 6.1 1 Example 8 Embodied 17.7 30 50 97.7 0.8 0.5 1 1 Example 9 Embodied 15 30 5 50 17.9 12.1 20 1 Example 10 Embodied 33 46 7 86 5 3 6 5 Example 11 Embodied 33 46 7 86 5 3 6 6 Example 12 Comparative Example 1 Comparative 30 65 3 98 2 1 Example 2 Comparative 33 46 7 86 5 3 6 1 Example 3 Comparative 33 46 7 86 5 3 6 1 Example 4 Comparative 1 68 10.3 79.3 7.4 4.4 8.9 1 Example 5 Comparative 70 20.6 3.1 93.7 2.3 1.3 2.7 1 Example 6 Comparative 48.9 20 10.4 79.3 7.4 4.4 8.9 1 Example 7 Comparative 3.1 95 0.6 98.7 0.5 0.2 0.6 1 Example 8 Comparative 14.2 19.8 60 94 2.2 1.2 2.6 1 Example 9 Comparative 15.3 21.4 3.3 40 21.4 12.9 25.7 1 Example 10 *Each of the shown content amount (wt %) of conductor-containing glass powder, organic vehicle, niobium oxide, and manganese oxide is relative to 100 wt % of the thick film resistor paste composition. *Each of the shown content amount (wt %) of ruthenium oxide, lead ruthenate, and conductive substances are relative to 100 wt % of the conductive substance-containing glass composition. *Each of the shown content amount (wt %) of silicon oxide, lead oxide, boron oxide, combined amount of these essential glass components, aluminum oxide, zinc oxide, and calcium oxide is relative to 100 wt % of the glass components.

(28) TABLE-US-00002 TABLE 2 Composition of thick film resistor paste Conductive substances Additives Composition of glass Content Content Content Content Content Content Content amount of amount Content amount amount amount Content Content amount Content amount ruthenium of lead amount of of of amount amount of amount of oxide ruthenate of glass organic niobium silicon of lead of boron aluminium of zinc calcium Comparative powder powder powder vehicle oxide oxide oxide oxide oxide oxide oxide Examples (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) (wt %) Comparative 6 17 36 40 1 33 47 7 5 3 5 Example 1 *Each of the shown content amount (wt %) of ruthenium oxide powder, lead ruthenate powder, glass powder, organic vehicle, and niobium oxide is relative to 100 wt % of the thick film resistor paste composition. *Each of the shown content amount (wt %) of silicon oxide, lead oxide, boron oxide, aluminum oxide, zinc oxide, and calcium oxide is relative to 100 wt % of the glass components.

(29) TABLE-US-00003 TABLE 3 High Embodied Converted temperature Resistance Examples and area TCR Evaluation value Comparative resistance (ppm/degrees of trimming change rate Examples (kiloohm) Celsius) property (%) Embodied 1 42 ? ?0.13 Example1 Embodied 50000 ?123 ? ?0.9 Example2 Embodied 0.2 252 ? ?0.2 Example3 Embodied 0.41 120 ? ?0.42 Example4 Embodied 2.2 20 ? ?0.21 Example5 Embodied 1.2 35 ? ?0.1 Example6 Embodied 0.5 65 ? ?0.4 Example 7 Embodied 1.2 40 ? ?0.15 Example8 Embodied 0.25 172 ? ?0.72 Example9 Embodied 1.5 ?10 ? ?0.33 Example10 Embodied 0.92 45 ? ?1.2 Example11 Embodied 0.87 51 ? ?1.6 Example12 Comparative 0.94 ?6 ? ?4 Example1 Comparative 0.93 ?30 X Example2 Comparative >100000 Example3 Comparative 0.2 250 ? 10 Example4 Comparative 0.35 165 ? ?3.1 Example5 Comparative 1.9 ?11 X Example6 Comparative 1.1 32 ? ?3.3 Example7 Comparative 0.48 110 X Example8 Comparative 0.24 173 ? ?4.1 Example9 Comparative 1.3 10 X Example10

(30) As shown in Table 3, the thick film resistors of Embodied Examples 1 to 12 were observed to have extremely low resistance value change rates before and after the electrostatic discharge tests and had excellent surge resistances, as compared with the thick film resistor of Comparative Example 1 formed by the conventional thick film resistor paste without using the conductive substance-containing glass powder. The thick film resistors of Embodied Examples 1 to 12 were formed by the thick film resistor pastes prepared by using the conductive substance-containing glass powders of the present invention.

(31) The thick film resistors of Comparative Examples 2, 6, 8, and 10 were observed to have insufficient trimming properties and were not suitable for commercialization. The thick film resistors of Comparative Examples 2, 6, 8, and 10 were formed by the thick film resistor pastes obtained by using the conductive substance-containing glasses that were prepared by using glass components of which boron oxide content were less than the claimed range of the present invention.

(32) Furthermore, the thick film resistor of Comparative Example 3 was observed to present almost no conductivity, because the resistance value of the conductive substance-containing glass powder became too high. The thick film resistor of Comparative Example 3 was formed by the thick film resistor paste obtained by using the conductive substance-containing glass of which content of the conductive substance was less than the claimed range of the present invention.

(33) Furthermore, the thick film resistor of Comparative Example 4 was observed to have extremely high resistance value change rate before and after the electrostatic discharge test and to have low surge resistance. The thick film resistor of Comparative Example 4 was formed by the thick film resistor paste obtained by using the conductive substance-containing glass of which content of the conductive substance was more than the claimed range of the present invention.

(34) Furthermore, the thick film resistors of Comparative Examples 5 and 7 were observed to have higher resistance value change rates before and after the electrostatic discharge tests and to have lower surge resistances, as compared with the thick film resistors of Embodied Examples 1 to 12. The thick film resistors of Comparative Examples 5 and 7 were formed by the thick film resistor pastes obtained by using the glass components whose content of silicon oxide or lead oxide, or the combined amount of these essential glass components were outside the claimed range of the present invention. The thick film resistor of Comparative Example 9 was also observed to have higher resistance value change rate before and after the electrostatic discharge test and to have lower surge resistance, as compared with the thick film resistors of Embodied Examples 1 to 12. The thick film resistor of Comparative Example 9 was formed by the thick film resistor paste using the glass components of which content of boron oxide was more than the claimed range of the present invention.

(35) From the above test results, it is recognized that the thick film resistor formed by using the thick film resistor paste of the present invention has excellent trimming property and surge resistance, and can be suitably used for electronic components which have been miniaturized in recent years.