JPH03146466A - Dielectric porcelain composition for combined circuit board - Google Patents

Abstract

PURPOSE:To obtain an insulator layer, a dielectric layer, etc., having superior high frequency insulating property by blending BaTiO3 with CaZrO3, Nb2O5 and ZnO in a prescribed ratio. CONSTITUTION:BaTiO3 is blended with CaZrO3, Nb2O5 and ZnO or Co2O3 so as to obtain a compsn. represented by formula I (where 5.0<=x<=14.0mol%, 1.0<=y<=3.0mol% and 0.5<=z<=3.0mol%) or formula V (where 5.0<=x<=14.0mol%, 1.0<=y<=3.0mol% and 0.25<=z<=1.5mol%) and an org. binder, a dispersant, a plasticizer, etc., are added as required. They are mixed and molded to produce a dielectric porcelain compsn. for a combined circuit board forming a dielectric layer. Electrode layers are formed on both sides of the dielectric layer to obtain a capacitor part and this capacitor part is held between insulator layers to produce a combined circuit board with a built-in capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a dielectric ceramic composition for a composite circuit board, which is applied to a dielectric layer forming a composite circuit board incorporating a capacitor.

[Prior art j] In recent years, various electronic components have rapidly become smaller and more densely packaged through the use of semiconductor integrated circuit elements such as ICs and LSIs. In addition to miniaturization, there has also been a demand for higher density. Therefore, progress has been made in increasing the density of electrical wiring through miniaturization and multilayering, and in chipping passive components such as capacitors and resistors in electronic circuits. Double-sided mounting connected to conductor layers for electrical wiring has been put into practical use.

However, with the remarkable development of semiconductor materials, electronic components are required to be smaller and more densely packaged, and these demands cannot be met by miniaturizing the passive components mentioned above. It was gone.

In order to meet these demands, a part of the capacitor, which is a passive element, is formed by thick-film printing a dielectric paste on an insulating substrate using a screen printing method, and an electrode layer and a conductor layer for internal wiring are formed by the same thick-film printing. Then, after laminating and pressing the insulating substrate and burning it, a conductor layer for electric wiring and a resistor layer formed by thick film printing similar to the above are baked on the surface of the laminated and integrated sintered body to hybridize it, Dielectric materials have been proposed with the aim of producing compact, high-density composite ceramic circuit boards that have excellent temperature characteristics over a wide range and large-capacity capacitor circuits. (Unexamined Japanese Patent Publication No. 63-224
(See Publication No. 107) [Problems to be Solved by the Invention] However, although this conventional composite ceramic circuit board has a dielectric constant of 100 or more, it has a dielectric constant of 1200 or more.
M that can be simultaneously fired and integrated at temperatures from °C to 1350 °C
gO-5iOz-CaO-AI! The difference in thermal expansion coefficient between 40°C and 200°C with the insulating substrate whose main component is om
0XIO-'/'C, which causes cracks in some capacitors after firing, and the dielectric constant is 15.
In the case of a dielectric material having a composition exhibiting a temperature of 0.00 or higher, the temperature characteristics of the dielectric material are -55°C based on the capacitance at 20°C.
Since the rate of change in capacity from +125° C. exceeds ±15%, there was a problem that it could only be used under extremely limited conditions.

[Object of the Invention] The present invention was devised in view of the above-mentioned drawbacks, and its purpose is to simultaneously burn out an insulator layer and a dielectric layer with excellent high frequency insulation properties, and to achieve excellent temperature characteristics over a wide range and large capacity. An object of the present invention is to provide a dielectric ceramic composition for a composite circuit board from which a highly reliable capacitor-embedded composite circuit board incorporating a part of a capacitor having the following characteristics is obtained.

[Means for Solving the Problems 1] The dielectric ceramic composition for a composite circuit board according to the present invention is a capacitor in which a part of a capacitor formed by providing electrode layers on the upper and lower surfaces of a dielectric layer is sandwiched between insulating layers. In the built-in composite circuit board, the compositional formula of the dielectric layer is (100-x - y -z) BaTi0m 6 x
caZros・yNbt05・zZnO However, X5VsZ represents mol% and is 5.0≦x≦14.0 1.0≦y≦3.0 0.5≦z≦3.0 or (100-x −y −z) BaTiOs-xc
aZrOs・y NbzOs・Z CotOaHowever, x, y, and z represent mol%, and are 5.0≦x≦14.0 1.0≦y≦3.0 0.25≦z≦1.5 This is a characteristic feature.

That is, in the composition formula of the dielectric layer, the value of X is 5.0 mol%.
In both cases, the coefficient of thermal expansion of the dielectric layer is less than 1.
22 If it exceeds 0 mol %, the dielectric constant decreases to 1500 or less and the temperature characteristics deteriorate.

Further, when the value of y is less than 1.0 mol%, the volume/volume change rate is out of the range of ±15% on the high temperature side of the temperature range of -55°C to +125°C. On the other hand, when the value of y exceeds 3.0 mol%, the temperature ranges from -55°C to +12°C.
The capacitance change rate deviates from the range of ±15% over the entire temperature range of 5°C.

On the other hand, for a value of 2, the composition formula is (100-x -y -z
) BaTiOs −x CaZr0= −y NbzO
If it is represented by s −z ZnO and is less than 0°5 mol%,
Or the composition formula is (100-x-y-z) BaTi
0.・xcaZrO, ・7NbzO5+ zco, 0
3 and less than 0.25 mol%, all -
On the high temperature side of the temperature range of 55°C to +125°C, the rate of change in capacity deviates from the range of ±15%. On the other hand, the composition formula is (10
0-x-y-z) BaTi0.・xCaZrO,・)
'NbzOs・z ZnO and the value of 2 exceeds 3.0 mol%, or the composition formula is (100-x -y
-z ) BaTi0゜・xcaZrO,・yNb*
It is expressed as os ・zcozOz, and the value of 2 is 1.5 mol%
-55°C to +125° if exceeding
The capacitance change rate deviates from the range of ±15% over the entire temperature range of C.

Therefore, the values of xs 3' and 2 in the compositional formula of the dielectric layer are respectively specified within the above ranges.

■Function] Use Ba as a dielectric layer for composite circuit boards with built-in capacitors.
Ti0. A dielectric material mainly composed of Nb, 0. and Zn
By dissolving either O or Cot(h), the rate of change in capacity over a wide temperature range becomes extremely small, within ±15%.

Furthermore, by dissolving both NbzOs, ZnO, Co, O, and CaZr01, which has extremely low thermal expansion, the heat of the dielectric layer can be reduced without affecting the capacitance change rate of the dielectric layer. Expanded Grudge 121 Xl0-7
It becomes possible to control the temperature to a low temperature of /℃ or less.

[Example 1] Next, dielectric ceramic MLt7. for composite circuit boards of the present invention was prepared. The object will be explained in detail based on examples.

The dielectric layer constituting the capacitor part has the composition shown in Table 1, with BaTiOs as the main component, CaZrOs, Nb, 05, ZnO or Co,
A suitable organic binder, dispersant, plasticizer and solvent are added to the raw material powder of the dielectric material consisting of 03 and mixed in a ball mill to prepare a slurry. The obtained slurry was punched out into a green sheet having a thickness of 25 μm to 55 μm to set the capacitor capacity by, for example, a conventionally well-known drawing method to obtain a dielectric sheet of 170 mm square.

Next, silver/palladium (Ag-
A conductive paste made by adding and mixing a metal powder such as a Pb) alloy with an appropriate solvent is used to produce an electrostatic paste that requires an electrode pattern of about 2 mm to 9In11 squares using a conventional thick film printing method such as screen printing. Printing was performed according to the capacity.

On the other hand, the insulator layer is made of MgO, Sin, CaO and A1.
A slurry was prepared by adding and mixing an organic binder dispersant, a plasticizer, and a solvent to the calcined powder of the mixture consisting of 0.03, and a green sheet with a thickness of 200 μm was shaped using the conventionally well-known doctor blade method. The green sheet was punched to obtain a 170 mm square insulator sheet, and through-holes were formed to ensure electrical continuity between the capacitor part and the upper and lower surfaces of the insulator layer, and the conductive paste was also applied to the through-holes. Filled.

Next, a plurality of laminated dielectric sheets made of barium titanate were sandwiched between the plurality of insulator sheets and thermocompression bonded, and the resulting laminate was exposed to air for 200 minutes.
Debinding at a temperature of 12°C to 400°C, followed by
The product is baked in the air at a temperature of 40'C to 1340C to be integrated to obtain an insulating substrate with a part of the capacitor built therein.

Thus, a conductor pattern for electrical wiring was formed on the insulating substrate after the firing and integration using a screen printing method using an Ag-Pb alloy paste, and electrodes were baked.

After confirming the presence or absence of a short circuit between the electrode layers of a part of the capacitor using the above evaluation sample using an LCR meter, the JIS
The capacitance of the capacitor part was measured under the measurement conditions of frequency IKk, input signal level l, and QVrms according to the regulations of C5102, and the relative dielectric constant (gr) was calculated from the capacitance. 55℃ to +125℃
The capacitance at °C was measured, and the capacitance change rate was calculated as a temperature characteristic (TCC) based on the capacitance at +25 °C.

In addition, the thermal expansion coefficients of the dielectric layer and the insulating layer were determined by incinerating a prismatic test piece of 3 mm in width, 3 openings in width, and 49 ma+ in length, which had the same composition as the evaluation sample, at the same time as the bottom of the pit of the evaluation sample. Then, the average coefficient of thermal expansion was measured in a temperature range of 40"C to 2O0"C.

The above results are shown in Table 1.

(Left below) [Advantageous Effects of the Invention 1] According to the dielectric ceramic m-paraboloid for a composite circuit board of the present invention, an insulating layer having excellent high frequency insulation properties and a dielectric layer having a high dielectric constant react with each other. It is possible to simultaneously bake and integrate the insulator layer and the dielectric layer at a low temperature, and the thermal expansion coefficients of the insulator layer and the dielectric layer can be made very similar to each other. It is possible to simultaneously incorporate a part of a capacitor with excellent temperature characteristics over a wide range and a large capacity without causing heat generation, and as a result, a compact, high-density capacitor-embedded composite circuit board that is ideal for hybrid boards, etc. can be obtained. Can be done.

Claims (1)

[Claims] (1) The compositional formula is (100-x-y-z)BaTiO_3.xCaZrO
_3・yNb_2O_5・zZnO However, x, y, and z represent mol%, and are for composite circuit boards consisting of 5.0≦x≦14.0 1.0≦y≦3.0 0.5≦z≦3.0 Dielectric porcelain composition. (2) The composition formula is (100-x-y-z)BaTiO_3・xCaZrO
_3・yNb_2O_3・zCO_2O_3 However, x, y, and z represent mol%, and are for composite circuit boards consisting of 5.0≦x≦14.0 1.0≦y≦3.0 0.25≦z≦1.5 Dielectric porcelain composition.