JP2002343602A - Thick-film resistor composition, thick-film resistor using the same and formation method the resistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thick-film resistor composition, that exhibits a high resistance value and can realize a thick-film resistor with reduced variation of a resistance value, and has a low baking temperature which is applicable for glass substrate, and a thick-film resistor using the same, and to provide its formation method. SOLUTION: This thick-film resistor composition contains a non-conductive glass powder (A), a conductive powder (B), and an organic vehicle (C). The (A) element contains 2-72 wt.% PbO, 5-30 wt.% B2 O3 , and 3-35 wt.% SiO2 in terms of oxide, and the (B) element is made of indium oxide-tin oxide powder, and furthermore, the (A) element and (B) element are mixed at ratios of 95-65 wt.% and 5-35 wt.%, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thick film resistor composition, a thick film resistor using the same, and a method of forming the same. More specifically, the present invention shows a high resistance value and a small variation in the resistance value. The present invention relates to a thick film resistor composition which provides a thick film resistor and has a low firing temperature applicable to a soda lime glass substrate for a plasma display, a thick film resistor using the same, and a method of forming the same.

[0002]

2. Description of the Related Art Conventionally, a thick film resistor composition is prepared by kneading a non-conductive glass powder and a conductive powder such as ruthenium oxide together with an organic vehicle.
Used as a resistive element material for thick film chip resistors. At that time, the organic vehicle is produced by dissolving an ethyl cellulose resin or the like in an organic solvent such as terpinol. The prepared thick film resistor composition is applied to an insulating substrate such as glass or ceramic by screen printing or the like, and then dried at a temperature at which an organic solvent can evaporate, and further at a temperature sufficient to soften the glass powder. By firing, a target thick film chip resistor was formed. In the conventional thick film resistor composition, the firing temperature is 700 to 900 ° C.,
On the other hand, the resistance value of the obtained resistor per unit area is 0.1.
It was 1 to 10 ¹⁰ Ω or more.

In recent years, plasma display panels, field emission displays, liquid crystal display panels and the like have been spotlighted. In these devices, soda lime glass or the like is used for a substrate, and depending on the lighting method, a thick film resistor is used. It is an essential component. Substrates such as soda-lime glass are softened and deformed by heating, so that there is a limit to the temperature at which they can be heated. When forming a thick film resistor on a substrate, it is necessary to limit the firing temperature of the thick film resistor composition to about 650 ° C., but the conventional thick film resistor composition achieves such a low firing temperature. That was impossible.

For this reason, attempts have been made to prepare a thick film resistor composition which can be applied even at a low firing temperature. For example, Japanese Patent Application Laid-Open No. 9-219301 discloses that the softening point is 350 to 550 ° C. _PbO-SiO 2 _-B 2 _{O 3}
-Al ₂ O ₃ system or _{PbO-SiO 2 -B 2 O 3} -Al
_A titanium oxide powder and a conductive titanium oxide powder or a conductive tin oxide powder were added to ₂ O ₃ -ZnO-based glass powder and ruthenium-based conductive powder and dispersed in an organic vehicle. Although a thick film resistor composition at -600 ° C. has been proposed, the resistance value per unit area of the obtained pressure film resistor is about 0.6 × 10 ⁵ Ω, and 10 ⁶ Ω. The above high resistance value has not been realized.

By the way, in a thick film resistor composition,
In order to control the resistance value of the obtained resistor, the compounding ratio of the conductive powder and the non-conductive glass powder is adjusted, but the resistance value of the resistor increases when the compounding ratio of the glass powder is increased. Rise. When a ruthenium oxide-based conductive powder is used, particularly in a region where the resistance value exceeds 10 ⁶ Ω, the resistance value increases sharply with an increase in the glass powder, making it difficult to control the resistance value. There is a problem that the variation in the resistance value also increases. In order to address this problem, inorganic additives (titanium oxide, tin oxide, etc.) for adjusting the resistance have been found in conventional thick film resistor compositions fired at 700 to 900 ° C. However, no such inorganic additive has been found in a low-temperature sintering type thick film resistor composition having a sintering temperature of 450 to 650 ° C., and in particular, a resistance value of 10 ⁶ Ω is obtained. In a region exceeding the above range, a problem remains in controlling the resistance value.

As described above, the use of thick film resistors is expanding to fields such as plasma displays and field emission displays using soda-lime glass or the like for the substrate. Because of the inability to sufficiently cope with such applications, there is a demand for a low-temperature-fired thick-film resistor composition that exhibits a high resistance value and provides a thick-film resistor with small variation in the resistance value, and is applicable to a glass substrate. Was.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thick-film resistor having a high resistance value and a small variation in the resistance value in view of the above-mentioned problems of the prior art. It is another object of the present invention to provide a thick film resistor composition having a low firing temperature applicable to the above, a thick film resistor using the same, and a method for forming the same.

[0008]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a thick film resistor composition containing a non-conductive glass powder, a conductive powder, and an organic vehicle has a glass composition. A glass powder having a specific composition as a powder, and further using indium oxide-tin oxide powder as a conductive powder, and then mixing the glass powder and the conductive powder at a specific ratio, the above-mentioned problem is achieved. And completed the present invention based on such findings.

That is, according to the first aspect of the present invention, there is provided a thick film resistor composition containing a non-conductive glass powder (A), a conductive powder (B), and an organic vehicle (C).
The component (A) contains 2 to 72% by weight of Pb in terms of oxide.
O, 5 to 30 wt% of _B 2 _{O 3} and 3 to 35 wt% of S
It contains iO ₂ , the component (B) is composed of indium oxide-tin oxide powder, and the components (A) and (B) are 95-65% by weight of the former and 5-35 of the latter. There is provided a thick film resistor composition characterized in that it is blended in a proportion of% by weight.

Further, according to the second aspect of the present invention, the first aspect
The present invention provides a thick film resistor composition characterized in that at least one inorganic additive (D) selected from TiO ₂ or SnO ₂ is blended with the component (A).

Further, according to the third aspect of the present invention, the first aspect is provided.
Alternatively, there is provided a method for forming a thick film resistor, which comprises applying the thick film resistor composition according to the second invention to an insulating substrate and then firing the composition at a temperature in the range of 450 to 650 ° C.

Further, according to a fourth aspect of the present invention, there is provided a thick-film resistor obtained by the method of the third aspect.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

1. Non-conductive glass powder (A) non-conductive glass powder used in the present invention (A) is a glass powder of _PbO-B 2 O 3 -SiO ₂ system of specific composition, softening of 430-650 ° C. Characterized by having points.

The lead component contained in the glass powder is preferably 2 to 72% by weight in terms of oxide (PbO). If the ratio of the lead component is less than 2% by weight, the softening point becomes too high, and the function of the binder may not be exhibited. On the other hand, if it exceeds 72% by weight, the softening point of the glass powder becomes too low, and the seepage of the glass on the resistor surface increases, which is not preferable.

The proportion of the boron component contained in the glass powder is preferably from 5 to 30% by weight in terms of oxide (B ₂ O ₃ ). If the proportion of the boron component is less than 5% by weight, the softening point becomes too high, and the function of the binder may not be exhibited. On the other hand, if it exceeds 30% by weight, the softening point of the glass powder becomes too low, and the seepage of the glass on the resistor surface increases, which is not preferable.

The silicon component contained in the glass powder constitutes the skeleton of the glass.
In O ₂₎ in terms of, preferably 3 to 35 wt%. If the proportion of the silicon component exceeds 35% by weight, the softening point becomes too high, and the function of the binder may not be exhibited. Meanwhile, 3
If the amount is less than% by weight, the softening point is too low, and the seepage of glass on the resistor surface increases, which is not preferable. Although the cause is unknown, if the proportion of the silicon component is small, it becomes difficult to control the resistance value by the addition amount of indium oxide-tin oxide.

The non-conductive glass powder (A) has at least one inorganic additive (D) selected from TiO ₂ or SnO ₂ as another component in order to increase the resistance of the thick film resistor. ) Can be added. Although the effect is inferior, at least one inorganic additive (D) selected from TiO ₂ powder or SnO ₂ powder is added to the thick film resistor composition in order to increase the resistance value of the thick film resistor. You can also. The amount of TiO ₂ and / or SnO ₂ added as other components or powder may be 0.5% by weight or more.

As described above, in the conventional thick film resistor composition fired at a high temperature, an inorganic additive is used to adjust the resistance value. However, indium oxide-tin oxide powder and glass powder are mainly used. In the low-temperature firing type thick film resistor composition of the present invention having a firing temperature of 450 to 650 ° C. as a component, by adding at least one inorganic additive (D) selected from TiO ₂ or SnO _2. The fact that the resistance of the thick film resistor was found to increase increased the resistance to 10 ^6.
Even in a region exceeding Ω, the resistance value of the thick film resistor can be effectively controlled.

Further, the non-conductive glass powder (A) includes:
In order to adjust the thermal expansion coefficient and the like, as necessary, Al ₂
Known oxides such as O ₃ and ZnO may be added.

On the other hand, the softening point of the non-conductive glass powder (A) is determined by changing the ratio of the above glass component to 430 in order to set the firing temperature of the thick film resistor composition at 450 to 650 ° C.
It is preferable to adjust the temperature to a range of 650 ° C. If the softening point of the glass powder is less than 430 ° C, the cause is unknown,
It becomes difficult to control the resistance value by the amount of indium oxide-tin oxide added. On the other hand, if the softening point exceeds 650 ° C., the softening of the glass becomes insufficient under the firing conditions used in the present invention, and a thick film resistor cannot be formed.

The particle size of the non-conductive glass powder (A) is preferably 5 μm or less so as to be uniformly mixed with the conductive powder, which is a fine powder, and to improve the firing efficiency. Particle size 5μ
In order to obtain a glass powder of m or less, a glass lump obtained by melting and cooling the raw material may be ground using a known ball mill, jet mill, or the like.

Although the glass powder functions as a binder for the conductive powder of the thick film resistor, in the present invention, the mixing ratio of the nonconductive glass powder (A) and the conductive powder (B) is usually The component (A) is 65 to 95% by weight, the component (B) is 35 to 5% by weight, preferably the component (A) is 70 to 90% by weight, and the component (B) is 30 to 10% by weight. It is. If the compounding ratio of the component (A) is less than 65% by weight, it does not function as a binder for the conductive powder, while if it exceeds 95% by weight, it becomes difficult to control the resistance value by the conductive powder.

2. Conductive Powder (B) The present invention is characterized in that indium oxide-tin oxide powder is used as the conductive powder (B). Indium oxide-tin oxide has a high specific resistance, and is 1 × 10 ⁻⁵ Ω / cm to 1 × 10 ⁻⁵ Ω / cm.
⁻⁴ Ω / cm. When a conductive powder having a high specific resistance is used, a high resistance value can be obtained without increasing the compounding ratio of a non-conductive glass powder that increases the resistance value exponentially, so that the resistance value can be easily controlled. Becomes

As described above, the mixing ratio of indium oxide-tin oxide powder to the inorganic component of the thick film resistor composition is 5%.
３５35% by weight, preferably 10-30% by weight. If the indium oxide-tin oxide powder is less than 5% by weight,
If the resistance value is difficult to control, on the other hand, if it exceeds 35% by weight, sintering of the thick film resistor composition becomes difficult, and a resistor cannot be formed. The particle diameter of the indium oxide-tin oxide powder is preferably 1 μm or less in order to make the resistor homogeneous.

3. Organic Vehicle (C) The organic vehicle (C) used in the present invention is not particularly limited, and an organic vehicle widely used in the technology of a thick film composition, for example, ethyl cellulose or an acrylic resin may be terpinol or butyl carbitol acetate. And the like can be used. The mixing ratio of the resin and the organic solvent may be appropriately determined in consideration of the suitability of the thick film resistor composition for screen printing.

4. Thick film resistor composition thick film resistor composition of the present invention, certain _PbO-B 2 O 3 -SiO ₂ based glass powder and indium oxide composition having a softening point of 430-650 ° C. - a tin oxide powder It is a composition blended at a specific ratio, and is characterized in that it can be fired at a low temperature.

The firing temperature of the thick film resistor composition is adjusted to 450 to 650 ° C. by changing the composition (softening point) of the glass powder. If the firing temperature is lower than 450 ° C., in a device such as a plasma display or a field emission display, after forming an element such as a thick film resistor,
Since there is a step of heating to 50 to 430 [deg.] C. for sealing, a problem occurs that the resistance value of the thick film resistor greatly changes in the sealing step. On the other hand, if the firing temperature exceeds 650 ° C., the soda lime glass, which is the substrate of these devices, is softened and deformed, so that the dimensional accuracy of the devices themselves cannot be ensured.

The method of mixing the components of the composition is not particularly limited. For example, a thick film resistor composition can be obtained by kneading glass powder, indium oxide-tin oxide powder, and an organic vehicle with three rolls or the like. Can be Further, a lubricant, an antioxidant, a viscosity modifier, an antifoaming agent, and the like can be added to the thick film resistor composition of the present invention, if necessary, as long as the object of the present invention is not impaired. .

5. Thick-film resistor and method of forming the same As a method of forming the thick-film resistor of the present invention, the thick-film resistor composition described above is used to be applicable to a glass substrate.
There is no particular limitation other than baking in a temperature range of 50 to 650 ° C. For example, a thick film resistor composition is applied to an insulating substrate such as glass or ceramic on which a gold electrode is formed by screen printing or the like, and an organic solvent is applied. Is evaporated and dried, and then fired using a belt furnace or the like. The thick film resistor of the present invention obtained by the above forming method has a thickness of 10
^It has an excellent feature of exhibiting a high resistance value of ⁶ Ω or more and having a small variation in the resistance value.

[0031]

EXAMPLES Examples and comparative examples of the present invention will be shown below, but the present invention is not limited to these examples.

Examples 1 to 14, Comparative Examples 1 to 5 As described in Tables 1 and 2, non-conductive glass powder (A)
A thick film resistor composition and a thick film resistor were manufactured by the following procedure. When the resistance value of the obtained thick film resistor was evaluated, the results as shown in Table 2 were obtained.

(Production of Non-Conductive Glass Powder (A)) The non-conductive glass powder (A) has the composition shown in Table 1
It was melted at 00 ° C., quenched, and pulverized with a ball mill to produce. Table 1 shows the particle size of the obtained glass powder.

(Production of Thick Film Resistor Composition) 70% by weight of an inorganic component obtained by mixing a nonconductive glass powder (A) and an indium oxide-tin oxide powder having a particle size of 0.1 μm in a ratio shown in Table 2 and an organic vehicle (C) 30% by weight was kneaded with a three-roll mill to obtain a thick film resistor composition. The organic vehicle (C) was obtained by mixing 4% by weight of ethylcellulose and 96% by weight of terpineol and heating and dissolving the mixture at 70 ° C.

(Manufacture of Thick-Film Resistor) A thick-film resistor composition of 1 m was placed on a 96% alumina substrate on which a gold electrode was formed by a thick-film method.
After screen printing to a size of mx 1 mm, it was fired in a belt firing furnace at a firing temperature x holding time shown in Table 2 to obtain a thick film resistor. The resistance values of the fifteen thick film resistors were measured with a digital multimeter, and the coefficient of variation of the resistance value was calculated by equation (1). Table 2 shows the obtained results. Coefficient of variation = (standard deviation of resistance value / average resistance value) × 100 (1) The coefficient of variation is desirably suppressed to 30% or less.

[0036]

[Table 1]

[0037]

[Table 2]

As is evident from the results in Table 2, the thick film resistor composition of the present invention has a low firing temperature of 650 ° C. or less. , 10
A high resistance value of ⁶ Ω or more is shown, and the variation of the resistance value is as small as 30% or less.

[0039]

As described above, according to the present invention,
A thick film resistor composition having a high resistance value and a small variation in the resistance value is provided, and a low firing temperature applicable to a soda lime glass substrate for a plasma display is obtained.

Claims (4)

[Claims] 1. A thick film resistor composition containing a non-conductive glass powder (A), a conductive powder (B) and an organic vehicle (C), wherein the component (A) is 2% in terms of oxide. ~ 72
Wt% of PbO, 5-30 wt% _B 2 _{O 3} and 3 to 3
It contains 5% by weight of SiO ₂ , the component (B) is composed of indium oxide-tin oxide powder, and the components (A) and (B) are 95% to 65% by weight of the former. Is contained at a ratio of 5 to 35% by weight. 2. The thick film resistor composition according to claim 1, wherein at least one inorganic additive (D) selected from TiO ₂ or SnO ₂ is blended with the component (A). 3. A method for forming a thick film resistor, comprising: applying the thick film resistor composition according to claim 1 or 2 to an insulating substrate, followed by firing at a temperature of 450 to 650 ° C. 4. A thick-film resistor obtained by the method according to claim 3.