JPH08153602A - Resistance paste internally used in low temperature fired substrate - Google Patents

Abstract

PURPOSE: To provide resistance paste, having less irregurality in resistance value, which can be internally used on a low temperature fired substrate by suppressing the reaction between a conductive component and substrate material. CONSTITUTION: In the title resistance paste, in which lead ruthenate is used as a conductive component, which can be used in a low temperature firing substrate or simultaneous firing can be possible, bismuth oxide of 1 pts.wt. or more against lead ruthenate of 1 pts.wt. is contained, or the glass containing bismuth oxide of glass composition of 1 pts.wt. is contained against ruthenate of 1 pts.wt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance paste used for electronic circuit parts, and more particularly to a resistance paste for forming a resistance circuit inside or / and outside a low temperature fired substrate.

[0002]

2. Description of the Related Art With the recent miniaturization of electronic devices, the demand for high-density integration of electronic circuits has increased, and ceramic substrates for electronic devices have multiple layers and fine pitch circuits. The demand for bare chip mounting is increasing. In order to meet these requirements, conductor resistance is low, and Au, Ag, and C capable of fine patterning are available.
A temperature at which a conductor such as u can be simultaneously fired, that is, 1000
A ceramic material that can be fired at a temperature below ℃ is required.

Conventionally, alumina and organic substrates have been used as substrates for electronic devices. However, the organic substrate has a large coefficient of thermal expansion of about 50 × 10 ⁻⁶ / ° C., is inferior in thermal conductivity to alumina, and is not suitable for satisfying the above requirements. Also, in alumina, since a high temperature of 1600 ° C. is required for firing, only W or Mo having a relatively high conductor resistance can be used as an internal conductor in the case of multilayering, which limits the circuit fine patterning. was there.

In order to deal with such a problem, Au, Ag, Cu or the like having a low conductor resistance, such as Ag and Ag-based metals, which are particularly advantageous in terms of cost, can be used as the inner conductor, and the thermal conductivity is superior to that of the organic substrate. Development of low-temperature firing substrate composition is underway.

The low-temperature fired substrate is made of glass and ceramic powder such as alumina, mullite, zirconia, etc. Since it can be fired at 1000 ° C. or lower, functional parts such as resistors can be built in by simultaneous firing. It has the feature. However, in the case of resistance, there is a problem that the resistance value is greatly varied due to the reaction between the glass in the substrate material and the glass in the resistance material or the conductive component at the present time.

[0006]

In view of such conventional problems, the present invention suppresses a reaction between a conductive component and a substrate material, and thus has a small variation in resistance value and is incorporated in a low temperature baking substrate. It is intended to propose a possible resistance paste.

[0007]

According to the present invention, in a resistance paste using lead ruthenate as a conductive component, which can be built in or co-fired in a low temperature firing substrate, bismuth oxide is added to 1 part by weight of lead ruthenate. 1 parts by weight or more, or 1 part by weight of lead ruthenate,
It is a gist of a resistance paste for embedding in a low temperature firing substrate, which is characterized in that glass containing 1 part by weight or more of bismuth oxide having a glass composition is used.

[0008]

[Function] One of the causes of variations when resistors are built in a low temperature fired substrate is decomposition of lead ruthenate, which is mainly used as a conductive component in a high resistance region.
Simultaneous firing of low-temperature firing substrate material and built-in resistor paste (co-fire) in order to embed a resistor in the low-temperature firing substrate.
Is required. Generally, the low-temperature firing substrate material is composed of glass and ceramic powder, and the resistance paste material is basically a mixture of glass and an inorganic conductive material. -Mutual diffusion by liquid is unavoidable.

It is believed that the decomposition of lead ruthenate is caused by the glass in the substrate material that has penetrated into the resistor during simultaneous firing of the low temperature fired substrate and the resistor paste. That is, due to the action of the glass in which the lead ruthenate contained in the resistor is infiltrated, it is decomposed into ruthenium oxide, which causes a variation in the resistance value and further causes foaming during the decomposition reaction, which causes defects such as blisters. Cause.

In order to suppress such decomposition of lead ruthenate, it is necessary to introduce bismuth oxide into the glass used for resistance.

As a method of introducing this bismuth oxide into the glass, the present invention takes a method of adding bismuth oxide alone to the resistance paste and / or a method of incorporating it into the glass in the resistor as a glass composition. . Also,
As the content, 1 part by weight or more of bismuth oxide is necessary with respect to 1 part by weight of lead ruthenate contained in the resistance paste, and preferably 1.5 parts by weight or more.
The reason is that when the amount of bismuth oxide contained in the resistor is less than 1 part by weight, it is not sufficient to suppress the decomposition reaction of lead ruthenate by the glass component that has penetrated into the resistor from the low temperature firing substrate.

[0012]

EXAMPLES SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ —ZnO—CaO system crystallized glass powder (SiO ₂ : 29 wt%, A
l ₂ O ₃ : 18 wt%, B ₂ O ₃ : 13 wt%, Zn
O: 27 wt%, CaO: 13 wt%) and Al ₂ O ₃
The powders were mixed using a ball mill in a weight ratio of 59:41 to obtain a composition for low temperature firing substrate. In addition, Al
_{The 2} O ₃ powder used had an average particle size of 0.5 to 1 μm.

48 parts by weight of butyral resin, 70 parts by weight of dibutyl phthalate as a plasticizer, 50 parts by weight of isopropyl alcohol and 50 parts by weight of methyl ethyl ketone as a solvent were added to 100 parts by weight of the composition for a low temperature fired substrate thus obtained. The slurry was prepared by mixing with a ball mill for an hour, and a green sheet was prepared on a PET film by a doctor blade method.

Next, lead ruthenate, glass powder having the composition shown in Table 1 and bismuth oxide powder were mixed in the proportions shown in Table 2, and 100 parts by weight of these mixtures were mixed with 35 parts by weight of a terpineol solution of ethyl cellulose as a vehicle. Parts were added and kneaded with a 3-roll mill to prepare a uniform paste.

The resistance paste obtained by the above method is printed on the above green sheet with silver paste used as an electrode, and then printed using a print pattern of 1 mm × 1 mm, 1
It was dried at 20 ° C. for 20 minutes.

Subsequently, three green sheets are formed by sandwiching the green sheet on which electrodes and resistors are printed in the center.
0kgf ^/ cm 2, 60~80 ℃, crimped under the conditions of 5 minutes, and cutting the sheet into a predetermined size, the maximum temperature 875
Firing was carried out at a temperature of 20 ° C for 20 minutes. Further, a silver electrode for measuring electric characteristics was provided on the uppermost layer, and it was connected to an internal electrode by a via hole using silver paste, so that electric characteristics of internal resistance could be measured.

With respect to the low-temperature fired substrate with a built-in resistor obtained by the above method, the resistance value and the resistance value variation (n = 25,
C. V = (σn / x) × 100), and the presence or absence of foaming was measured and observed by observing the cross section. Table 3 shows the results. The thickness of the obtained built-in resistor was about 10 μm.

From the results shown in Table 3, by containing 1 part by weight or more of bismuth oxide with respect to 1 part by weight of lead ruthenate, the reaction between the conductive component and the substrate material can be suppressed, and the variation in resistance value can be reduced. It can be seen that a resistance paste that can be embedded in the low temperature fired substrate is obtained.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

As described above, the resistance paste for embedding a low-temperature baked substrate according to the present invention can suppress the reaction between the conductive component and the substrate material, so that the resistance value variation is small and can be incorporated in the low-temperature baked substrate. It has an excellent effect.

Claims (2)

[Claims] 1. A resistance paste which can be built-in or co-fired in a low temperature firing substrate and which uses lead ruthenate as a conductive component, contains 1 part by weight or more of bismuth oxide per 1 part by weight of lead ruthenate. The characteristic low-temperature fired substrate built-in resistor paste. 2. A resistance paste which can be built-in or co-fired in a low temperature firing substrate and which uses lead ruthenate as a conductive component, contains 1 part by weight or more of bismuth oxide having a glass composition with respect to 1 part by weight of lead ruthenate. A low-temperature fired substrate built-in resistor paste, characterized by using a glass.