JPH0624857A - Multilayer ceramic board - Google Patents

Abstract

PURPOSE:To provide a multilayer ceramic board good for multilayer wiring on which an electronic circuit of conductors, resistors, etc., are formed in multiple layers. CONSTITUTION:This multilayer ceramic board contains an internal electrode 1, a ceramic layer 2 contg. the internal electrode has a structure different from that of a ceramic protective layer 3, and the ceramic layer 2 has a composition different from that of the ceramic protective layer 3. Consequently, the board can be sintered at 750-950 deg.C, Au, Ag, Ag-Pd, Cu, etc., are used for the internal electrode, the volume resistivity, permittivity, dielectric loss tangent, dielectric breakdown strength, flexural strength, etc., as the characteristics of a multilayer wiring board on which the electronic circuit of conductors, resistors, etc., are formed in multiple layers are satisfied, and further the TCC is easily adjusted to + or -0-100ppm/ deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer ceramic substrate used for multi-layer wiring for forming electronic circuits such as conductors and resistors in multi-layers.

[0002]

2. Description of the Related Art At present, as an electronic component for forming a circuit in multiple layers, a first method of manufacturing a circuit by alternately printing a circuit and an insulating layer on a fired alumina substrate, and baking the circuit, and a non-fired method. There is a second method in which the circuit is printed on the ceramic substrate, the circuits are laminated so that the circuits do not come into contact with each other, and the circuit is pressed and then fired. In the case of the first method, the insulating layer formed thereon has irregularities due to the influence of the circuit, and the unevenness becomes larger in the upper layer. When this unevenness becomes large, it becomes difficult to print the next circuit on it, and the limit is usually around 10 layers. On the other hand, in the second method, since the circuit printing is always performed on the substrate in a state close to a plane, it is possible to manufacture one having a large number of stacked layers and form a high-density integrated circuit. . Since the multilayer ceramic substrate used for this high-density integrated circuit has an internal electrode layer of 100 μm or less, the properties of the ceramic layer in which the internal electrode is interposed and the ceramic protective layer surrounding the ceramic layer are directly related to the circuit. Affects I / O signals. The ceramic substrate composition used for the substrate of the second method includes Al ₂ O ₃ powder and 15w.
There are those in which glass powder of t% or less is fixed with an inorganic binder, and those in which Pb and B are mixed in an Al ₂ O ₃ —SiO ₂ system and fired at a low temperature.

[0003]

However, the Al ₂ O ₃ powder of the second conventional method and the glass powder of 15 wt% or less fixed by an inorganic binder have an extremely high firing temperature of 1450 to 1600 ° C. Since the cost is high, expensive materials such as Mo and W, which do not deteriorate at this firing temperature, are used as the material for forming the circuit, and the workability is poor because firing is required in a reducing atmosphere. What is mixed with Pb or B in an Al ₂ O ₃ —SiO ₂ system at about 10 wt% and fired at a low temperature has a ceramic layer in which internal pores, that is, porosity is relatively large, and thus an internal electrode is interposed. Surface roughness is increased, and the dielectric loss tangent tends to be deteriorated. In order to reduce the internal pores of the ceramic layer, that is, the porosity, it is necessary to mix Pb and B in an amount of 20 wt% or more, so that the firing shrinkage rate becomes large, and the firing shrinkage behavior between the ceramic layer and the internal electrode. However, peeling occurs between the layers.
In addition, the rate of change of capacitance with respect to temperature change (hereinafter TCC
However, there is a problem that it becomes large.

The present invention solves the above-mentioned conventional problems. It can be fired at an extremely low temperature, that is, 750 to 950 ° C., and a paste such as Au, Ag, Ag-Pd, Cu is used as an internal electrode. It is possible to achieve volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc.
Satisfies various characteristics as a multilayer wiring board for forming electronic circuits such as conductors and resistors in multiple layers, and has a TCC of ± 0 pp
The present invention provides a multilayer ceramic substrate that can be adjusted to m / ° C to 100 ppm / ° C.

[0005]

To solve this problem, a multilayer ceramic substrate of the present invention is a multilayer ceramic substrate having internal electrodes, wherein the structure of the ceramic layer in which the internal electrodes are interposed is the same as the structure of the ceramic protective layer. Different multilayer ceramic substrates. Specifically, the structure of the ceramic layer in which the internal electrode is interposed in the range of 5 μm to 100 μm from the internal electrode is different from the structure of the ceramic protective layer, and the porosity of the ceramic layer in which the internal electrode is interposed is 5.00%. Hereinafter, the porosity of the ceramic protective layer is 5.00 to 10.00.
% Range. Further, in the multilayer ceramic substrate having internal electrodes, the ceramic composition of the ceramic layer in which the internal electrodes are interposed is different from the ceramic composition of the ceramic protective layer, and the ceramic composition of the ceramic layer in which the internal electrodes are interposed is Al ₂ O ₃ -SiO ₂ -Ca
_{O-ZnO-TiO 2 -B 2} O 3 -MgO based, or, Al
_{2 O 3 -SiO 2 -CaO-SrO} -ZrO 2 -BaO-B
₂ O ₃ -TiO ₂ system, ceramic composition of the ceramic protective _{layer, Al 2 O 3 -SiO 2 -PbO} -B 2 O 3 -CaO-M
_{gO-Na 2 O-K 2} O-TiO 2 system, or, Al ₂ O ₃ -
_{SiO 2 -SrO-ZrO 2 -BaO-} B 2 O 3 -TiO 2
It is a multi-layer ceramic substrate different from that of the system.

The reasons for limiting each item will be described below. It is difficult to form a multilayer ceramic substrate itself because it is difficult to manufacture and laminate a sheet having a thickness of about 6 μm or less with a ceramic layer of 5 μm or less with an internal electrode interposed. The structure of the ceramic layer in which the internal electrode is interposed and the structure of the multilayer ceramic substrate including the ceramic protective layer having a layer having a thickness of 100 μm or more from the internal electrode and different from the structure of the ceramic layer in which the internal electrode is interposed are Due to the different firing shrinkage behavior of layers, peeling between layers occurs during firing,
Not preferable.

The porosity of the ceramic layer in which the internal electrodes are interposed is preferably 5.00% or less. When the porosity is 5.00% or more, the internal pores of the ceramic layer are relatively large, so that the surface roughness of the ceramic layer in which the internal electrodes are interposed becomes large, the dielectric loss tangent deteriorates, and the direct entry into the circuit is prevented. It adversely affects the output signal.

The porosity of the ceramic protective layer is preferably 5.00% or more in order to stabilize the firing shrinkage behavior of the ceramic layer in which the internal electrodes are interposed and the ceramic protective layer. A porosity of 10.00% or more is not preferable because the mechanical strength of the multilayer ceramic substrate decreases.

The ceramic composition of the ceramic layer interposing the internal electrodes has an extremely low temperature, that is, 750 to 950.
Al ₂ O ₃ —SiO ₂ —CaO—ZnO—TiO ₂ —B ₂ which can be fired at ℃, and whose porosity can be controlled and TCC can be easily adjusted.
O ₃ -MgO based, _{or, Al 2 O 3 -SiO 2 -CaO} -S
_{rO-ZrO 2 -BaO-B 2} O 3 -TiO 2 based ceramic composition is desirable.

The ceramic composition of the ceramic protective layer is extremely
Can be fired at a very low temperature, that is, 750 to 950 ° C,
Porosity can be controlled to 5.00 to 10.00%, and
Relatively mechanical, the main constituent material of multilayer ceramic substrates
Al with high strength and easy TCC adjustment₂O₃-Si
O₂-PbO-B₂O₃-CaO-MgO-Na₂OK ₂
O-TiO₂System or Al₂O₃-SiO₂-SrO-Z
rO₂ -BaO-B₂O ₃-TiO₂ System ceramic composition
Is desirable.

[0011]

With this structure, it can be fired at a temperature extremely lower than the conventional one, that is, at 750 to 950 ° C., and it can be used as an internal electrode of a paste such as Au, Ag, Ag-Pd, Cu which is widely used in thick film technology. In addition, the multilayer ceramic substrate has high mechanical strength, excellent thermal conductivity, relatively low dielectric constant, large insulation resistance, and excellent moisture resistance. Since the porosity of the ceramic layer is small, the surface roughness of the ceramic layer is small, so that the dielectric loss tangent can be small. Furthermore, by adjusting the ratio of the ceramic composition, TC
The control of C can be facilitated.

[0012]

EXAMPLES Examples of the present invention will be described below.

First, the glass frit, which is a raw material for forming the ceramic layer with the internal electrodes interposed, is Al ₂ O _{3 in} wt%.
45, SiO ₂ 27, ZnO 8.1, TiO ₂ 8.
1, CaO 8.0, B ₂ O ₃ 2.5, MgO 1.
Each raw material was prepared by a usual method so as to have the composition of 3, and melted with stirring at a temperature of 1400 to 1500 ° C, and after melting, granulated or flaked to prepare a glass frit. .

Next, the glass frit and CaTiO _{3 of} titanate were weighed so as to be 85 wt% and 15 wt%, respectively, and pulverized and mixed with a ball mill to obtain a composition of the present invention. A binder was added to the pulverized and mixed composition.
Was added for 10 minutes by weight, granulated and molded, and then fired at 950 ° C. for 15 minutes. The relative density of this fired body was measured and found to be 9
Since it was 9.98%, the diameter is 30 mm and the thickness is 0.35.
After processing to mm, the Ag electrode was baked and the TCC was measured. As a result, it was ± 0 ppm / ° C at -25 ° C to + 85 ° C. Therefore, various binders, plasticizers, and solvents are added to this pulverized and mixed composition and kneaded to obtain a viscosity of 10 ps to 30
A ps paste was made. This paste was made into a green sheet having a thickness of 0.05 mm by a conventional doctor method.

Next, the glass frit as a raw material for producing the ceramic protective layer is SiO ₂ 22.0, P in wt%.
bO 8.1, B ₂ O ₃ 2.7, CaO 3.6, Mg
O1.35, Na ₂ O 1.35, K ₂ O 0.9, Ti
Each raw material was blended by a usual method so as to have a composition of O ₂ 5.0, melted with stirring at a temperature of 1400 to 1500 ° C., and after melting, granulated or flaked, and A
A glass frit was manufactured by adding 55 wt% of 1 ₂ O ₃ .

Next, the glass frit and CaTiO _{3 of} titanate were weighed so as to be 85 wt% and 15 wt%, respectively, and pulverized and mixed with a ball mill to obtain a composition of the present invention. A binder was added to the pulverized and mixed composition.
Was added for 10 minutes by weight, granulated and molded, and then fired at 950 ° C. for 15 minutes. The relative density of this fired body was measured and found to be 9
Since it was 9.98%, the diameter is 30 mm and the thickness is 0.35.
After processing to mm, the Ag electrode was baked and the TCC was measured. As a result, it was ± 0 ppm / ° C at -25 ° C to + 85 ° C. Therefore, various binders, plasticizers, and solvents are added to this pulverized and mixed composition and kneaded to obtain a viscosity of 10 ps to 30
A ps paste was made. This paste was made into a green sheet having a thickness of 0.05 mm by a conventional doctor method. Then, an Ag paste is printed by about 10 μm on the green sheet which becomes the ceramic layer in which the internal electrodes are interposed by a screen printing method to form a green sheet which becomes the ceramic protective layer and a circuit. Each sheet was laminated as described above, and then thermocompression-bonded at 35 ° C. under a pressure of about 50 tons, and baked at 950 ° C. for 15 minutes.

When various characteristics of the fired substrate were measured, the volume resistivity was 10 ¹⁴ to ¹⁶ Ω, the dielectric constant was 10 to 15,
Dielectric loss tangent ≤ 5 × 10 ^-4 , dielectric breakdown strength 700-900k
V / cm, bending strength 1500-2000 kg / cm ² ,
It was TCC (-25 degreeC- + 85 degreeC) +/- 0 ppm / degreeC. That is, results were obtained that satisfied the characteristics as a multilayer wiring board in which electronic circuits such as conductors and resistors were formed in multiple layers. Figure 1
A cross-sectional view of the multilayer ceramic substrate in the embodiment of the present invention is shown in FIG.

In FIG. 1, 1 is an internal electrode, 2 is a ceramic layer in which the internal electrode is interposed, and 3 is a ceramic protective layer. 4 is an internal pore of 5 to 10 μm. The porosities of the ceramic layer and the ceramic protective layer in which the internal electrodes are interposed were measured to be 3.5% and 8.0%, respectively.
The porosity is different from the above, and the space between the ceramic layer in which the internal electrode is interposed and the ceramic protective layer is about 43 μm, which is a satisfactory result.

Further, the glass frit as a raw material for producing the ceramic layer in which the internal electrodes are interposed is wt%, and Al ₂ O _{3 is used.}
8.5, SiO ₂ 27.0, CaO 8.5, Sr
O12.0, ZrO ₂ 25.0, BaO 11.0,
The respective raw materials were blended so as to have a composition of TiO ₂ 3.0 and B ₂ O ₃ 5.0, and a glass frit was manufactured in the same manner as the above method. Next, the glass frit and CaTiO _{3 of} titanate were weighed so as to be 90 wt% and 10 wt%, respectively, and pulverized and mixed with a ball mill to obtain a composition of the present invention. A binder was added to the pulverized and mixed composition.
Was added at 10 wt%, granulated, molded, and then fired at 900 ° C. for 15 minutes. The relative density of this fired body was measured and found to be 9
Since it was 9.98%, the diameter is 30 mm and the thickness is 0.35.
After processing into mm, the Ag electrode was baked and the TCC was measured. As a result, it was +30 ppm / ° C at -25 ° C to + 85 ° C. Therefore, various binders, plasticizers and solvents are added to the pulverized and mixed composition and kneaded to obtain a viscosity of 10 ps to 3
A 0 ps paste was made. This paste was made into a green sheet having a thickness of 0.05 mm by a conventional doctor method.

The glass frit as a raw material for producing the ceramic protective layer was made of Al ₂ O ₃ 8.5 and SiO ₂ 2 in wt%.
7.0, SrO 12.0, ZrO ₂ 29.0, Ba
The respective raw materials were blended so as to have a composition of O12.5, TiO ₂ 3.0 and B ₂ O ₃ 8.0, and a glass frit was manufactured in the same manner as the above method.

Next, the glass frit and SrTiO _{3 of} titanate were weighed so as to be 90 wt% and 10 wt%, respectively, and pulverized by a ball mill and mixed to obtain a composition of the present invention. A binder was added to the pulverized and mixed composition.
Was added at 10 wt%, granulated and molded, then at 900 ° C for 15
Minutes were fired. When the relative density of this fired body was measured,
Since it was 99.98%, the diameter is 30 mm and the thickness is 0.3.
After processing to 5 mm, the Ag electrode was baked and the TCC was measured. As a result, it was +30 ppm / ° C at -25 ° C to + 85 ° C. Therefore, various binders, plasticizers and solvents are added to the pulverized and mixed composition and kneaded to obtain a viscosity of 10 ps to
A 30 ps paste was made. This paste was made into a green sheet having a thickness of 0.05 mm by a conventional doctor method.

Next, in the same manner as in the above method, a green sheet which becomes a ceramic layer with an internal electrode interposed is printed with an Ag paste to a thickness of about 10 μm by a screen printing method to form a ceramic protective layer. -The sheets are laminated so that the sheet and the circuit are configured, and then at 50C at about 50 ° C.
It was thermocompression bonded at a pressure of ton and baked at 900 ° C. for 15 minutes.

When various characteristics of the fired substrate were measured, the volume resistivity was 10 ¹⁴ to ¹⁶ Ω, the dielectric constant was 10 to 15,
Dielectric loss tangent ≤ 5 × 10 ^-4 , dielectric breakdown strength 700-900k
V / cm, bending strength 1500-2000 kg / cm ² ,
It was TCC (-25 degreeC- + 85 degreeC) +35 ppm / degreeC. That is, results were obtained that satisfied the characteristics as a multilayer wiring board in which electronic circuits such as conductors and resistors were formed in multiple layers.

When the porosities of the ceramic layer and the ceramic protective layer with which the internal electrodes are interposed were measured,
The porosity is different from 3.0% to 7.0%, and there is about 4 between the ceramic layer with the internal electrode and the ceramic protective layer.
A satisfactory result of 3 μm was obtained.

The glass frit, which is a raw material for forming the ceramic layer with the internal electrodes interposed, is Al ₂ O ₃ 4 in wt%.
5, SiO ₂ 27, ZnO 8.1, TiO ₂ 8.
1, CaO 8.0, B ₂ O ₃ 2.5, MgO 1.
In the composition of 3, the composition when the glass frit and the CaTiO _{3 of the} titanate are 92 wt% and 8 wt%, respectively, and the glass frit of the raw material for producing the ceramic protective layer is Al ₂ O ₃ 8 wt% .5, SiO ₂ 2
7.0, SrO 12.0, ZrO ₂ 29.0, Ba
The composition of O 12.5, TiO ₂ 3.0, B ₂ O ₃ 8.0, and SrTi of this glass frit and titanate.
A sheet was made in the same manner as the above method with a composition of O ₃ of 92 wt% and 8 wt% respectively, and Ag paste was printed, and the sheets were laminated so that a circuit was formed, and 850
It was baked at 15 ° C for 15 minutes. When various characteristics of the fired substrate were measured, the same values as above were obtained for the volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, and bending strength. TCC
(−25 ° C. to + 85 ° C.) was +65 ppm / ° C. The porosities of the ceramic layer and the ceramic protective layer, in which the internal electrodes are interposed, were measured to be 3.5%,
The porosity is different from 7.0%, and a satisfactory result of about 43 μm was obtained between the ceramic layer in which the internal electrode is interposed and the ceramic protective layer. The glass frit as a raw material for producing the ceramic layer in which the internal electrode is interposed is wt% and is Al.
₂ O ₃ 8.5, SiO ₂ 27.0, CaO 8.5,
SrO 12.0, ZrO ₂ 25.0, BaO 11.
0, TiO ₂ 3.0, B ₂ O ₃ 5.0, the glass frit and the CaTiO 3 titanate.
_{When 3} is 95 wt% and 5 wt% respectively, the composition and the glass frit of the raw material for producing the ceramic protective layer are
Al ₂ O ₃ 55.0, SiO ₂ 22. 0,
PbO 8.1, CaO 3.6, MgO 1.35,
Na ₂ O 1.35, K ₂ O 0.9, B ₂ O ₃ 2.7,
The composition of TiO ₂ 5.0 and the glass frit and CaTiO _{3 of} titanate are 95 wt% and 5 w, respectively.
A sheet was prepared with the composition of t% in the same manner as described above, and A
g paste was printed, each sheet was laminated so as to form a circuit, and baked at 800 ° C. for 15 minutes. When various characteristics of the fired substrate were measured, the same values as above were obtained for the volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, and bending strength. TCC (-25 ° C to + 85 ° C) is +80
It was ppm / ° C.

The porosities of the ceramic layer and the ceramic protective layer in which the internal electrodes are interposed were measured.
The porosity is different from 3.0% to 8.0%, and the space between the ceramic layer in which the internal electrodes are interposed and the ceramic protective layer is about 4%.
A satisfactory result of 3 μm was obtained.

Further, a sheet of Au, Ag-Pd, Cu or the like is used.
The same results as above were obtained when the circuit was constructed using the strike as an internal electrode.

In addition to the above ceramic composition, since the titanate forms a solid solution with the glass frit, TC is used.
It was difficult to adjust and control C. The above results (Table 1)
~ (Table 3).

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

According to the present invention, as can be seen from (Table 1) to (Table 3), firing can be realized at an extremely low temperature as compared with the conventional multilayer ceramic substrate, and the TCC can be easily adjusted.

[0033]

The present invention solves the above-mentioned problems of the prior art. It can be fired at an extremely low temperature, that is, 750 to 950 ° C, and a paste such as Au, Ag, Ag-Pd, Cu is used as an internal electrode. It can be used, and satisfies various characteristics such as volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc. as a multilayer wiring board for forming electronic circuits such as conductors and resistors in multiple layers. , Furthermore, TCC is ± 0
It is possible to realize a multilayer ceramic substrate that can be easily adjusted to ppm / ° C. to 100 ppm / ° C.

[Brief description of drawings]

FIG. 1 is a sectional view of a multilayer ceramic substrate according to an embodiment of the present invention.

[Explanation of symbols]

 1 Internal Electrode 2 Ceramic Layer with Internal Electrode 3 Ceramic Protective Layer 4 Internal Pore

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication H01L 23/15 9355-4M H01L 23/14 C

Claims (8)

[Claims] 1. A multilayer ceramic substrate having internal electrodes,
A multilayer ceramic substrate, wherein a structure of a ceramic layer in which an internal electrode is interposed is different from a structure of a ceramic protective layer located near the ceramic layer. 2. The porosity of the ceramic layer interposing the internal electrodes is 5.00% or less, and the porosity of the ceramic protective layer is 5.0.
The multilayer ceramic substrate according to claim 1, characterized in that it is in the range of 0 to 10.00%. 3. The multilayer ceramic substrate according to claim 1, wherein the structure of the ceramic layer in which the internal electrode is interposed is within a range of 5 μm to 100 μm from the internal electrode, which is different from the structure of the ceramic protective layer. 4. The multilayer ceramic substrate according to claim 2, wherein the structure of the ceramic layer in which the internal electrode is interposed is 5 μm to 100 μm from the internal electrode, which is different from the structure of the ceramic protective layer. 5. A multilayer ceramic substrate having internal electrodes,
The ceramic composition of the ceramic layer in which the internal electrodes intervene,
The multilayer ceramic substrate according to claim 1, wherein the ceramic composition of the ceramic protective layer is different from that of the ceramic protective layer. 6. A multilayer ceramic substrate having internal electrodes,
The ceramic composition of the ceramic layer in which the internal electrodes intervene,
_{Al 2 O 3 -SiO 2 -CaO-} ZnO-TiO 2 -B 2 O 3
-MgO system, _{or, Al 2 O 3 -SiO 2 -CaO} -S
_{rO-ZrO 2 -BaO-B 2} O 3 -TiO 2 system, ceramic composition of the ceramic protective layer, Al ₂ O ₃ -SiO _{2
-PbO-B 2 0 3 -CaO-} MgO-Na 2 O-K 2 O-
TiO ₂ system, _{or, Al 2 O 3 -SiO 2 -SrO} -ZrO
The multilayer ceramic substrate according to claim 5, which is different from the _2- BaO-B ₂ O ₃ -TiO ₂ system. 7. The multilayer ceramic substrate according to claim 6, wherein the ceramic composition of the ceramic layer in which the internal electrode is interposed is different from the ceramic composition of the ceramic protective layer in the range of 5 μm to 100 μm from the internal electrode layer. 8. The porosity of the ceramic layer in which the internal electrodes are interposed is 5.00% or less, and the porosity of the ceramic protective layer is 5.0.
The multilayer ceramic substrate according to claim 7, which is in a range of 0 to 10.00%.