JPH0590070A - Composite printed circuit board with built-in capacitors - Google Patents

Abstract

PURPOSE:To realize a built-in type high permittivity capacitor and a built-in type temperature compensation capacitor having a stabilized characteristic by sandwiching such high permittivity capacitor and temperature compensation capacitor with insulator layers consisting of MgO, SiO, CaO and borosilicate magnesium glass. CONSTITUTION:Dielectric layers 4, 4' are formed by a ceramic composition mainly consisting of barium titanate (BaTiO3) and temperature compensating dielectric ceramics. The main elements of an insulator layer 1 sandwiching capacitors 2, 2' are formed by magnesia(MgO), silica(SiO2) and calcia(CaO) within the range enclosed by the points A, B, C, D, E, F expressed by weight ratio and borosilicate magnesium glass mainly consisting of silica, boricoxide(B2 O3) and barium oxide(BaO) having the parts by weight exceeding 1 but under 15 for the total 100 parts by weight of magnesia(MgO), silica (SiO2) and calcia(CaO).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor-incorporated composite circuit board having a capacitor, a resistor and a conductor layer for electric wiring.

[0002]

2. Description of the Related Art In recent years, various electronic parts have become ICs and LSIs.
Miniaturization and high-density mounting are rapidly progressing by using semiconductor integrated circuit elements such as the above, and accordingly, the insulating substrate on which the semiconductor integrated circuit elements and the like are mounted are also downsized, and higher density is required. It was Therefore, miniaturization and multi-layering of electrical wiring have been promoted, and passive components such as capacitors and resistors in electronic circuits have been made into chips. Furthermore, miniaturized passive components are provided on both sides of an insulating substrate. The double-sided mounting connected to the conductor layer has been put to practical use. However, with the remarkable development of semiconductor materials, electronic components are required to be further miniaturized and mounted at high density, and it is possible to satisfy the demand for miniaturization of the passive components. It was gone.

In order to meet such demands, therefore, an insulating layer is provided on one or both sides of a capacitor portion formed by sequentially laminating a dielectric layer and an electrode layer, and firing and integration are simultaneously performed on the surface of the insulating layer. A composite ceramic substrate has been proposed in which a conductor layer for electric wiring and a resistor layer are formed by a screen printing method or the like, and the conductor layer and the resistor layer are baked and hybridized to achieve miniaturization and high density. (Japanese Patent Publication No. 62-21260, Japanese Patent Publication No. 63-5)
5795).

[0004]

However, this conventional composite ceramic substrate is not suitable for barium titanate (BaT).
iO ₃ ) and dielectric ceramics for temperature compensation, such as barium titanate (BaTi ₄ O ₉ ), calcium titanate (CaTiO ₃ ), magnesium titanate (Mg ₂ T).
iO ₄ ), lanthanum titanate (La ₂ Ti ₂ O ₇ ), strontium titanate (SrTiO ₃ ) or neodymium titanate (Nd ₂ Ti ₂ O ₇ ) as the main component of the dielectric layer. In addition, the dielectric layer is sandwiched by an insulating layer made of alumina (Al ₂ O ₃ ) or steatite (MgSiO ₃ ) and fired and integrated, and there is an advantage that the strength of the insulating substrate itself is high. However, there is a problem that the firing temperature is as high as 1300 ° C. to 1400 ° C. and the dielectric layer and the insulating layer react with each other, so that a dielectric layer having desired characteristics cannot be obtained.

Moreover, it is difficult to match the firing temperatures of the insulating layer and the dielectric layer, and cracks are generated in the dielectric layer due to the difference in thermal expansion between the insulating layer and the dielectric layer, resulting in insulation as a capacitor. There was a problem that the resistance and the dielectric breakdown voltage would be lower than the desired characteristic values.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide an insulating layer having a high frequency insulating property, which is composed mainly of MgO, SiO ₂ , CaO and magnesium borosilicate glass, and has a high dielectric constant. That a dielectric layer mainly composed of barium titanate (BaTiO ₃ ) having a high rate can be simultaneously sintered and integrated, and a capacitor having a high capacitance and a temperature compensating capacitor having a stable temperature characteristic are respectively incorporated. An object of the present invention is to provide a possible composite circuit board.

[0007]

A composite circuit board with a built-in capacitor according to the present invention comprises barium titanate (BaTiO 3).
₃ ) and a ceramic composition mainly composed of temperature-compensating dielectric ceramics as a dielectric layer, and the main component of the insulating layer for sandwiching the capacitor part is represented by the following weight ratio A shown in FIG. B, C, D, E, magnesia range surrounded by points of F (MgO), silica (SiO ₂₎ and calcia (CaO), magnesia (MgO), silica (SiO ₂₎ and calcia (CaO ), The insulating layer is composed of magnesium borosilicate glass in an amount of more than 1 and less than 15 with respect to 100 parts by weight in total, and the insulating layer comprises forsterite (Mg ₂ SiO ₄ ) and merwinite (C).
a ₃ MgSi ₂ O ₈ ), monticerite (CaMgSi
O ₄ ), akermanite (Ca ₂ MgSi ₂ O ₇ ) or enstatite (MgSiO ₃ ) at least one crystal phase is contained, and a capacitor portion formed from the dielectric and the dielectric layer and the electrode layer is formed. The cladded insulator layer is characterized by being co-fired to form an integral sintered body. However, X, Y, and Z are magnesia (M
gO), silica (SiO ₂ ) and calcia (CaO) are represented by weight%.

[0008] That is, when the MgO content in the insulator exceeds 59% by weight, the firing temperature exceeds 1300 ° C., the reactivity with the dielectric material becomes large, and simultaneous firing is not possible. Moreover, periclase (MgO) is present as a crystal phase. Moisture resistance deteriorates due to precipitation. On the other hand,
If it is less than 31% by weight, the insulation resistance value and the dielectric breakdown voltage of the capacitor part are lowered, which exceeds the practical range. Further, when SiO ₂ exceeds 59% by weight, the coefficient of thermal expansion of the insulating layer decreases, the difference in thermal expansion between the insulating layer and the dielectric layer becomes large, and cracks occur in the dielectric layer. The desired dielectric properties cannot be obtained. On the other hand, if it is less than 31% by weight, the firing temperature is 1300 ° C. or higher, and the firing cannot be performed simultaneously with the dielectric material.

On the other hand, when CaO exceeds 29% by weight, the reactivity with the dielectric material becomes large, the simultaneous firing is not possible, and C
Calcium silicate such as aSiO ₃ or Ca ₂ SiO ₄ is deposited, and the moisture resistance is deteriorated, and the insulation resistance value and the dielectric breakdown voltage are decreased, which exceeds the practical range. On the other hand, if it is less than 5% by weight, the coefficient of thermal expansion of the insulating layer decreases, and for the same reason as described above, cracks occur in the dielectric layer and desired stable dielectric characteristics cannot be obtained.

Further, when the content of magnesium borosilicate glass is 15% by weight or more, the firing temperature of the insulating layer becomes 1200 ° C. or lower, and the capacitor portion formed by the dielectric layer and the electrode layer cannot be fired at the same time. On the other hand, when the content is 1% by weight or less,
There is a problem that the firing temperature becomes 1300 ° C. or higher and the firing cannot be performed simultaneously with the dielectric material. Therefore, the main component of the insulator layer is specified in the above range.

[0011]

[Function] By adjusting the magnesia (MgO), silica (SiO ₂ ), calcia (CaO) and magnesium borosilicate glass, which are the main components of the insulating layer having the capacitor portion attached, so as to fall within the above range, A dielectric material mainly composed of barium titanate (BaTiO ₃ ) and a temperature compensating dielectric ceramic sinters the insulating material 1
Simultaneous firing at a firing temperature of 210 ° C to 1280 ° C,
Forsterite (Mg ₂
In addition to the SiO ₄ ) crystal phase, merwinite (Ca ₃ MgS) having a coefficient of thermal expansion different from that of the forsterite crystal phase.
i ₂ O ₈ ), monticerite (CaMgSiO ₄ ), akermanite (Ca ₂ MgSi ₂ O ₇ ) or enstatite (MgSiO ₃ ) at least one crystal phase can be formed to adjust the thermal expansion coefficient of the insulator. Therefore, the occurrence of thermal stress after firing and integration is extremely reduced.

In addition, since the softening temperature of the insulating material decreases as the content of magnesium borosilicate glass in the insulating composition increases, the coefficient of thermal expansion of the insulating material and the dielectric material during the temperature decrease during firing is decreased. The residual stress caused by the difference can be reduced, and as a result, the generation of cracks in the dielectric layer can be prevented.

[0013]

EXAMPLE A composite circuit board with a built-in capacitor of the present invention will be described in detail with reference to the example shown in FIG. Figure 2
FIG. 3 is a cross-sectional view showing an example of a composite circuit board with a built-in capacitor of the present invention. In the figure, 1 is an insulator layer, 2,
2'is a capacitor part, 3 is a conductor for electric wiring, and the capacitor parts 2, 2'are alternately laminated dielectric layers 4 and electrode layers 5 and temperature compensation mainly composed of barium titanate (BaTiO ₃ ). It is composed of a dielectric layer 4'having an insulating dielectric ceramic as a main component and an electrode layer 5 '.

The composition of the insulator layer 1 is shown by the weight% of magnesia (MgO), silica (SiO ₂ ), and calcia (CaO) represented by X, Y, and Z, respectively.
The following points A, B, C, D, E, F MgO, SiO ₂ and CaO within the range surrounded by, and M
For 100 parts by weight of gO, SiO ₂ and CaO in total,
Ceramic raw material powder consisting of magnesium borosilicate glass in an amount of more than 1 and less than 15 is mixed, and the mixture is mixed with 1
Calcination is performed at a temperature of 000 ° C to 1300 ° C.

Then, a suitable organic binder, a dispersant, a plasticizer and a solvent are added to and mixed with the ceramic powder obtained by crushing the calcined product to prepare a slurry, and the slurry is formed into a sheet by, for example, a conventionally known doctor blade method. An insulator layer is formed by stacking a plurality of green sheets obtained by forming the green sheet.

The condenser parts 2 and 2'are made of Ba.
A slurry prepared by adding and mixing an organic binder, a solvent and the like to a finely powdered dielectric material containing TiO ₃ and a temperature compensating dielectric as main components is formed into a sheet by a conventionally known pulling method.

Next, a silver / palladium (Ag-Pd) alloy paste is applied on the green sheet to a predetermined electrode pattern by a conventionally known screen printing method or the like to form electrode layers 5 and 5 '.

The insulator layer 1 and the capacitor section 2,
In order to establish continuity between the upper and lower surfaces of 2 ', a through hole portion 6 is formed on the green sheet of the insulator and the dielectric material by punching or the like, and the through hole portion 6 is filled with the alloy paste.

Then, the above-mentioned insulator, the green sheets of the dielectrics containing barium titanate (BaTiO ₃ ) and the temperature-compensating dielectric ceramics as main components are laminated and thermocompression-bonded, and the obtained laminated body is exposed to the atmosphere. , 200 ° C to 400
Debinding at a temperature of ℃, then 1210 ℃ ~ 1
By firing and integrating at a temperature of 280 ° C., an insulating substrate having the capacitor parts 2 and 2 ′ built therein is obtained.

In particular, the capacitor parts 2 and 2 ′ have dielectric layers mainly composed of temperature compensating dielectric ceramics on the upper and lower surfaces of the dielectric layer 4 mainly composed of barium titanate (BaTiO ₃ ) having a high dielectric constant. By stacking the body layers 4 ′, it is possible to suppress the movement of Ti and Ba, which have a large diffusion rate in the dielectric layer, at the same time when they are fired and integrated, and the temperature characteristics of the capacitor part are deteriorated. Can be prevented.

In this way, a conductor pattern for electrical wiring of Ag-Pd system and a resistance pattern of ruthenium oxide (RuO ₂ ) or the like are formed by printing on the surface of the insulating layer 1 which has been fired and integrated, and at a temperature of about 850 ° C. in the atmosphere. By firing, a composite circuit board with a built-in capacitor having the resistor 7 can be obtained.

Copper (C
When the paste containing u) as a main component is used, a resistance pattern is formed with a resistor material containing lanthanum boride (LaB ₆ ) or tin oxide (SnO ₂ ) as a main component, and the paste is formed in a nitrogen atmosphere at about 900 ° C. By firing at a temperature of, a composite circuit board with a built-in capacitor similar to the above can be obtained.

As the inevitable impurities remaining in the insulating layer 1, iron oxide (Fe ₂ O ₃ ) and alumina (Al ₂
The total amount of O ₃ ) is MgO, SiO ₂ , CaO and A
When the total amount of l ₂ O ₃ is 100 parts by weight, if the amount is 5 parts by weight or less, various characteristics of the capacitor part are not deteriorated.

Next, the present invention will be specifically described based on the following examples. Ceramic raw material powders composed of MgO ₂ , SiO ₂ , CaO and magnesium borosilicate glass were mixed so that the composition of the insulating layer would be the composition ratio shown in Table 1,
The mixture was calcined at a temperature of 1100 ° C to 1250 ° C. Then, pulverize and adjust the calcination product to a desired particle size,
A suitable organic binder and a solvent are added to and mixed with the obtained raw material powder to form a slurry, and a green sheet having a thickness of about 200 μm is formed from the slurry by a doctor blade method, and then punched into the green sheet. Processing was performed to obtain a 170 mm square insulator sheet.

On the other hand, barium titanate (BaTiO ₃ )
In order to set the capacity of each capacitor by adding and mixing an appropriate organic binder and a solvent to each raw material powder containing the temperature-compensating dielectric material as a main component to form a slurry, and pulling up the slurry. 20 μm to 60 in thickness
A green sheet of μm was formed, and the green sheet was punched to obtain a 170 mm square dielectric sheet.

Next, an electrode pattern of about 1 mm to 10 mm square is printed on the above-mentioned two kinds of dielectric sheets by a thick film printing method such as screen printing using Ag-Pd alloy paste according to the required capacitance. Formed. The Ag-Pd alloy paste was also filled in the through-hole portions previously formed on the insulating sheet and the dielectric sheet by screen printing or the like.

Thereafter, between the insulating sheets, on the upper and lower surfaces of the dielectric sheet laminated body made of barium titanate,
A plurality of laminated dielectric sheets made of temperature compensating dielectric ceramics are sandwiched and thermocompression-bonded, and the obtained laminated body is debindered at a temperature of 200 ° C. to 400 ° C. in the atmosphere, and then shown in Table 1. Firing in air at temperature.

After confirming the presence or absence of a short circuit between the electrode layers of the capacitor part for high capacity and temperature compensation by using the above-mentioned evaluation sample using an LCR meter, a frequency of 1 KHz and an input signal were measured by the LCR meter in accordance with JIS C 5102. The capacitance of the high-capacity capacitor section is measured under the measurement condition of level 1.0 Vrms, and the relative permittivity (ε _r ) is calculated from the capacitance, and the temperature-compensating capacitor section has a temperature range of −55 ° C. to 125 ° C. The capacitance at 0 ° C. was measured, and the rate of change of the capacitance was calculated as a temperature characteristic (TCC) based on the capacitance at 25 ° C.

The insulation resistance value of each capacitor section is a resistance value measured 60 seconds after applying a DC voltage of 25V, and the insulation breakdown voltage is applied between the terminals of the capacitor section at a boosting rate of 100V per second. The voltage value at the moment when the leakage current value at that time exceeded 1.0 mA.

On the other hand, the crystal phase of the insulating layer was identified by an X-ray diffraction pattern on the surface of the evaluation sample by performing X-ray diffraction using the evaluation sample.

The coefficient of thermal expansion of the insulating layer and each of the dielectric layers has the same composition as that of the evaluation sample and is 3 mm in the vertical direction,
A rectangular rod-shaped test piece having a width of 3 mm and a length of 40 mm was fired at the same time as the firing of the evaluation sample, and the average coefficient of thermal expansion in the temperature range of 40 ° C. to 800 ° C. was measured.

The above results are shown in Tables 1 to 9.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

[0037]

[Table 5]

[0038]

[Table 6]

[0039]

[Table 7]

[0040]

[Table 8]

[0041]

[Table 9]

The composite circuit board with a built-in capacitor of the present invention is not limited to the above-mentioned embodiment, but if resistors, which are passive components, are formed on both sides of the insulating board, the size can be further reduced. It goes without saying that high density can be realized.

[0043]

According to the composite circuit board with a built-in capacitor of the present invention, magnesia (MgO), silica (SiO ₂ )
And an insulator layer mainly composed of calcia (CaO) and excellent in high frequency insulation, and a dielectric layer mainly composed of barium titanate (BaTiO ₃ ) having a high dielectric constant and a temperature compensation dielectric layer. Since it becomes possible to perform firing and integration simultaneously at low temperature without reacting with each other, and the coefficient of thermal expansion of the insulator layer and the dielectric layer can be made to be extremely close to each other, cracks in the dielectric layer can occur. Built-in miniaturized and densified capacitor ideal for hybrid boards, etc. that have a built-in capacitor with high electrostatic capacity that is excellent in insulation resistance and dielectric breakdown voltage and temperature compensating capacitor without causing defects such as A composite circuit board can be obtained.

[Brief description of drawings]

1 is a part of the composition of an insulating layer according to the present invention, Mg
It is a ternary system diagram which shows the composition range of O, SiO, and CaO.

FIG. 2 is a sectional view showing an embodiment of a composite circuit board with a built-in capacitor of the present invention.

[Explanation of symbols]

 1 Insulator layer 2, 2'Capacitor part 4, 4 'Dielectric layer 5, 5' Electrode layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Yamaguchi 1-4 No. 4 Yamashita-cho, Kokubun-shi, Kagoshima Kyocera Stock Company Research Institute (72) Inventor Shinjiro Shimo No. 1-4 Yamashita-cho, Kokubun-shi, Kagoshima Kyocera Corporation (72) Inventor Nobuyoshi Fujikawa, 1-4 Yamashita-cho, Kokubun City, Kagoshima Prefecture Kyocera Corporation Inside Research Institute

Claims (3)

[Claims] 1. A composite circuit board with a built-in capacitor in which electrode layers are provided on the upper and lower surfaces of a dielectric layer to form a capacitor portion, and the capacitor portion is sandwiched by an insulating layer, wherein the dielectric layer is barium titanate ( BaTiO ₃ ) and a ceramic composition containing a temperature compensating dielectric ceramic as a main component, and the main component of the insulating layer sandwiching the capacitor part is shown by the following weight ratios A, B and C shown in FIG. , D, E, F
Of magnesia (MgO), silica (SiO ₂ ) and calcia (CaO), and magnesia (MgO), silica (SiO ₂ ) and calcia (Ca)
O based on 100 parts by weight of a total of 1 to 15 parts by weight of silica (SiO ₂ ), magnesia (MgO), boron oxide (B ₂ O ₃ ), barium oxide (BaO) as a main component. A composite circuit board with a built-in capacitor, which is composed of magnesium silicate glass. However, X, Y,
Z is magnesia (MgO), silica (Si
O ₂ ) and% by weight of calcia (CaO). _{2. The} forsterite (Mg ₂
SiO ₄ ) and melwinite (Ca ₃ MgSi
₂ O ₈ ), monticerite (CaMgSiO ₄ ), akermanite (Ca ₂ MgSi ₂ O ₇ ), or enstatite (MgSiO ₃ ), and at least one crystal phase is contained therein. Composite circuit board. 3. The dielectric layer and the insulator layer sandwiching the capacitor portion formed of the dielectric layer and the electrode layer are co-sintered integral sintered bodies.
And the composite circuit board with a built-in capacitor described in 2.