JPH07187766A - Composition for ceramic base plate - Google Patents

Abstract

PURPOSE:To obtain a composition for high-frequency ceramic base plates by containing a glass component, titanate salts, ceramics and, when needed, wallastonite in a prescribed proportion. CONSTITUTION:Individual raw material powders are weighted, mixed, molten, and cooled down to obtain glass flakes comprising (calculated as oxides) 20 to 50wt.% of SiO2, 5 to 20wt.% of Ai2O3, 10 to 20wt.% of CaO, 0 to 10wt.% of BaO, 1 to 10wt.% of MgO, 0 to 20wt.% of ZnO, 5 to 20wt.% of TiO2, 5 to 15wt.% of B2O3, and 4 to 25wt.% of PbO. Further, 60 to 85wt.% of this glass component, 5 to 20wt.% of one or more titanates selected from CaTiO3, SrTiO3, MgTiO3 10 to 35wt.% of one or more ceramics selected from Al2O3, ZrO2, ZrSiO4, TiO2, MgO and the like are used and combined with 5wt.% or less amount of wallastonite to give the objective composition for ceramic base plates. The composition is used to form green sheets. Electronic circuits are printed on the green sheets, and they are laminated, and fired to give the multilayered circuit base plate for high-frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for a ceramic substrate, and is particularly preferable as a material for a high-frequency multilayer wiring substrate formed by laminating electronic circuit layers such as conductors and resistors in multiple layers and firing the layers. The present invention relates to a ceramic substrate composition that can be used.

[0002]

2. Description of the Related Art A multilayer wiring board is a board suitable for downsizing of a device, in which electronic circuits such as conductors and resistors are printed on the surface of an unfired ceramic board (green sheet), etc. A plurality of printed unfired ceramic substrates (green sheets) are stacked and fired. BACKGROUND ART Conventionally, various low-temperature fired multilayer substrate materials capable of firing at the same time as a low resistance conductor having a relatively low melting point such as Ag, Ag—Pd, Au and Cu have been provided. In addition, JP-A-4-28618
Japanese Patent Publication No. 1 discloses a composition for a ceramic substrate composed of glass frit and titanate. In addition, the inventors of the present invention have disclosed that, in Japanese Patent Application No. 5-45773, Ag, Ag-Pd, A
When a conductor material such as u or Cu or a resistor material such as RuO ₂ is co-fired, the warpage of the multilayer substrate caused by a mismatch in thermal expansion coefficient, wettability, and other characteristics between the two,
Provided is a composition for a ceramic substrate, which improves defects such as delamination at the interface between the substrate and the conductor material or resistor material.

[0003]

However, the low temperature multi-layer substrate material, which has been conventionally provided and can be co-fired with a low resistance conductor having a relatively low melting point, can be fired at a low temperature, but it is not affected by temperature change. Rate of change in capacitance (hereinafter TCC
Is too large, and particularly when it is used for a high frequency substrate, there is a drawback that the quality is not stable. on the other hand,
The composition for a ceramic substrate described in JP-A-4-286181 can adjust the TCC in the range of ± 0 to ± 100 ppm / ° C, but this composition for a substrate is generally used. are Ag, Ag-Pd, Au, when resistor material and co-fired, such as conductive materials and RuO _2, such as Cu, the thermal expansion coefficient therebetween, wettability, shrinkage, by mismatch other characteristics, a multilayer substrate There are drawbacks such as warping and peeling (delamination) at the interface between the substrate and the conductor material or resistor material. Furthermore, in the composition for a ceramic substrate described in Japanese Patent Application No. 5-45773, TCC is ± 0.
Adjustment is now possible within the range of ± 50ppm / ℃. However, Ag, Ag-Pd, A used as internal electrodes
Due to the diversification of the shapes of the conductor materials such as u and Cu and the resistor materials such as RuO ₂ and the diversification of the layer thickness and the number of layers of the green sheets, the heat generated between the composition for a ceramic substrate and the conductor materials and the resistor materials described above. Unless the expansion coefficient difference, wettability, contraction rate difference, and other characteristics differences are further improved, the multilayer board may warp slightly or delamination may occur at the interface between the board and the conductor material or resistor material. It became clear that a slight defect occurred.

Therefore, the present invention solves the above-mentioned drawbacks of the prior art, and uses a low resistance conductor having a relatively low melting point such as Ag, Ag-Pd, Au, or Cu as an internal electrode of a multilayer substrate at a relatively low temperature (about Can be co-fired at 800-1000 ℃,
In addition, it satisfies general characteristics such as volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc. required for a multilayer wiring board for forming electronic circuits in multiple layers, and is necessary for the stability of the quality of high-frequency boards. Small TCC (± 0 to ± 50 ppm
/ ° C.), and further, it is intended to provide a composition for a ceramic substrate that does not warp the multilayer wiring substrate after firing and does not cause peeling of an electronic circuit.

[0005]

In order to achieve the above object, the composition for a ceramic substrate of the present invention has a SiO ₂ content of 20 to 50% by weight and an Al ₂ O ₃ content of 5 to 20% in terms of oxides. % By weight, 10 to 20% by weight of CaO, 0 to 10% by weight of BaO,
0-10% by weight of MgO, 0-20% by weight of ZnO, TiO
₂ to 5 to 20% by weight, B ₂ O ₃ to 5 to 15% by weight, PbO to 4 to 25% by weight, glass component 60 to 85% by weight, titanate 5 to 20% by weight, ceramic 10 The first feature is that the content is up to 35% by weight. The composition for a ceramic substrate of the present invention has, in addition to the above first characteristic, 5% by weight with respect to the total amount of the glass component, the titanate, and the ceramic.
The second feature is that it includes the following wollastonite. In addition to the first or second characteristic, the composition for a ceramic substrate of the present invention has a titanate of CaTi.
The third feature is that it is composed of O ₃ , SrTiO ₃ , MgTiO ₃ , or at least one of solid solutions of these titanates. Further, the composition for a ceramic substrate of the present invention has, in addition to any one of the above first to third characteristics,
A fourth feature is that the ceramic is made of at least one of alumina, zirconia, zircon, titania, magnesia, and mullite.

In the above, if the glass component is less than 60% by weight, it becomes difficult to densify the substrate, and the dielectric breakdown strength and bending strength decrease. On the other hand, if the glass component exceeds 85% by weight, the reaction with titanate, ceramics and wollastonite proceeds too much during sintering, which makes it difficult to adjust the TCC and also difficult to adjust the shrinkage ratio. The titanate is used in an amount of 5 to 20% by weight. For example, CaTiO ₃ , SrTi
A titanate composed of O ₃ , MgTiO ₃ or at least one of solid solutions of these titanates has a negative TCC.
Since it has characteristics, the TCC of the substrate is ± 0 to ± 50 by mixing with a glass component having positive TCC characteristics and sintering.
It can be adjusted within ppm / ℃. If the titanate is less than 5% by weight, it has no effect as a TCC modifier. On the contrary, 20% by weight
If it exceeds, not only TCC becomes a negative value than −50, but also it becomes difficult to densify the substrate. Of the above titanates, CaTiO ₃ is the most preferable in consideration of the sintering property of the substrate.

The ceramic is used at 10 to 35% by weight.
For example, alumina, zirconia, zircon, titania,
Magnesia and mullite, alone or in combination, not only contribute to adjusting the thermal expansion coefficient of the substrate and imparting heat resistance, but also reduce the shrinkage ratio of the substrate to Ag, Ag-Pd, A.
It can be matched with a conductor material such as u or Cu or a resistor material such as RuO ₂ . If the ceramic content is less than 10% by weight, it becomes difficult to adjust the shrinkage ratio of the sintered body, and the substrate is slightly warped. If it exceeds 35% by weight, it becomes difficult to densify the substrate and the withstand voltage characteristics deteriorate. The above-mentioned zirconia also includes partially stabilized zirconia and stabilized zirconia.

A small TCC (±) which satisfies general characteristics such as volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc. required for a multilayer wiring board and which is necessary for stability of quality of a high frequency board. (0 to ± 50 ppm / ° C), and in order to obtain each of these characteristics in a well-balanced manner so as not to warp the multilayer wiring board after firing and peel off the electronic circuit, the glass component and the titanate are used. More preferably, the ratios of the ceramic and the ceramic are 63 to 80% by weight, 7 to 15% by weight, and 12 to 30% by weight, respectively. In this case and in the first feature described above, the sum of the glass component, the titanate, and the ceramic is
100% by weight.

The wollastonite (CaO.Si
O ₂ ) serves as an external crystal nucleating agent for lowering the crystallization temperature and improving the crystallinity, thereby improving the heat resistance and bending strength of the substrate. Further, it is possible to reduce variations in substrate characteristics. However, since the wollastonite itself does not have heat resistance, the heat resistance of the substrate is deteriorated when the content exceeds 5% by weight with respect to the total amount of the glass component, the titanate, and the ceramic.

The glass component will be described. SiO ₂ is a glass-forming oxide, and if it is less than 20% by weight, the softening temperature becomes too low, and anorthite (C
aO ・ Al ₂ O ₃・ 2SiO ₂ ) and celsian (BaO
・ Al ₂ O ₃・ 2SiO ₂ ) and titanite (CaO ・ T
Since it is a constituent component of iO ₂ · SiO _2, it is difficult for these crystal phases to precipitate. The precipitation of these crystal phases improves the heat resistance and bending strength of the obtained substrate. On the other hand, when the SiO ₂ content exceeds 50% by weight, the coefficient of thermal expansion of the obtained substrate becomes too low. This SiO ₂ is 22-45
Weight percent is more preferred.

Al ₂ O ₃ is a glass intermediate oxide, and A
If the content of l ₂ O ₃ is less than 5% by weight, the glass transition point becomes too low and one of the crystal phases, CaO · Al ₂ O ₃ · 2S.
Precipitation of iO ₂ or BaO.Al ₂ O ₃ .2SiO ₂ becomes difficult, and the chemical durability of the substrate also deteriorates. Conversely, Al ₂ O
_{When 3} exceeds 20% by weight, the liquidus temperature becomes too high and devitrification occurs during melting, so high temperature melting is required. This Al ₂ O
₃ to 8 to 16% by weight is more preferable.

CaO is a glass-modifying oxide and a crystal constituent. The CaO is less than 10 wt%, the thermal expansion coefficient of the substrate becomes too small, which is one _{CaO · Al 2 O 3 · 2SiO} 2 precipitation of the crystal phase becomes difficult.
On the other hand, when CaO exceeds 20% by weight, the thermal expansion coefficient of the substrate becomes too large and the chemical durability deteriorates. This CaO is more preferably 12 to 18% by weight.

BaO is a glass-modified oxide. By adding BaO as a glass component, CaO.Al ₂
O ₃ · 2SiO ₂ plus BaO · Al ₂ O ₃ · 2Si
Although O ₂ is precipitated, it is preferable, but if it is added in excess of 10% by weight, the thermal expansion coefficient of the substrate becomes too large and the chemical durability deteriorates. The BaO content is more preferably 8% by weight or less. MgO is a glass modified oxide. If it exceeds 10% by weight, cordierite (2MgO.
2Al ₂ O ₃ .5SiO ₂ ) crystals are deposited, the coefficient of thermal expansion of the substrate becomes too low, and the bending strength decreases. This MgO is more preferably 0.5 to 8% by weight. ZnO is used as a fluxing agent and a thermal expansion coefficient adjusting agent. ZnO is 20
If it exceeds 5% by weight, the glass transition point is lowered, the coefficient of thermal expansion of the substrate is too small, and the heat resistance is also lowered. This ZnO is more preferably 3 to 17% by weight.

TiO ₂ imparts chemical durability to the substrate and is one of the crystalline phases of CaO.TiO ₂ .SiO _2.
It is a component of ₂ . If TiO ₂ is less than 5% by weight, Ca
It becomes difficult to precipitate the crystal phase of O ・ TiO ₂・ SiO ₂ ,
On the other hand, if TiO ₂ exceeds 20% by weight, the liquidus temperature becomes too high and devitrification occurs during melting, so high temperature melting is required. This TiO ₂ is more preferably 7 to 18% by weight.

B ₂ O ₃ not only serves as a flux for glass but also as a sintering aid for the ceramic substrate, and if it is less than 5% by weight, it becomes difficult to densify the sintered body. If it exceeds 15% by weight, it reacts with other materials such as conductors. This B ₂ O ₃ is more preferably 6 to 13% by weight.

PbO is used as a fluxing agent, a thermal expansion coefficient adjusting agent, and a component for improving the adhesion between an electronic circuit layer such as a conductor and a resistor and a substrate. This PbO has a large effect of preventing peeling between the substrate and the electronic circuit layer and a large effect of preventing warpage of the substrate on which the electronic circuit layer is arranged. If PbO is less than 4% by weight, the thermal expansion coefficient of the substrate cannot be sufficiently increased, and it is difficult to sufficiently increase the adhesive strength between the substrate and the electronic circuit layer. On the other hand, if the PbO content exceeds 25% by weight, the coefficient of thermal expansion of the substrate becomes too high, heat resistance deteriorates, and chemical durability also deteriorates. This PbO is 7-20% by weight
Is more preferable.

The composition for ceramic substrate according to the present invention is produced, for example, as follows. First, the glass composition is oxide conversion weight%, SiO ₂ is 20 to 50 weight%, Al
₂ O ₃ 5-20 wt%, CaO 10-20 wt%, BaO
Is 0 to 10% by weight, MgO is 0 to 10% by weight, ZnO is 0 to
20 wt%, TiO ₂ 5-20 wt%, B ₂ O ₃ 5-15
The raw material powders are weighed and mixed so that the weight% and PbO are 4 to 25% by weight, melted, and then cooled to form glass flakes. And the glass component consisting of this glass flake is 60 to 85% by weight, CaTiO ₃ , SrTi
5 to 20% by weight of titanate composed of O ₃ , MgTiO ₃ or a solid solution of these titanates, and at least one of alumina, zirconia, zircon, titania, magnesia and mullite. Glass flake, titanate powder and ceramic powder are weighed out so that the ratio of ceramic is 10 to 35% by weight, and if necessary, based on the total amount of glass flake, titanate powder and ceramic powder. Wollastonite powder is added, pulverized and mixed so that the content becomes 5% by weight or less. Thereby, the composition for ceramic substrate of the present invention can be obtained.

The production of a multilayer substrate from the composition for ceramic substrate of the present invention is carried out, for example, as follows. First, to the composition for a ceramic substrate of the present invention obtained above, a binder, a plasticizer, and a solvent suitable as a conventional method are added and kneaded to prepare a slurry, and this slurry is then doctor blade. A green sheet is formed by a method or the like, then the electronic circuit layer material is printed on this green sheet, and then a plurality of the printed green sheets are stacked and fired. As a result, a multi-layer substrate in which electronic circuit layers are formed in multiple layers can be obtained.

[0019]

According to the composition for a ceramic substrate of claim 1, Ag, Ag-Pd, Au, and Ag, Ag-Pd, Au, are formed by forming a multilayer substrate using the composition for a ceramic substrate.
A low resistance conductor such as Cu having a relatively low melting point can be co-fired at a relatively low temperature (about 800 to 1000 ° C) as an internal electrode of a multi-layer substrate, and as a multi-layer wiring substrate for forming electronic circuits in multiple layers. Satisfies general characteristics such as required volume resistivity, dielectric constant, dielectric loss tangent, dielectric breakdown strength, bending strength, etc., and especially small TCC (± 0 to ± 50 ppm) required for quality stability of high frequency board. It is possible to obtain a ceramic multilayer substrate which can be suppressed to / ° C.) and which does not warp the multilayer wiring substrate after firing and peel off the electronic circuit. Further, according to the composition for a ceramic substrate according to claim 2, in addition to the effect of the configuration according to claim 1, 5% by weight or less based on the total amount of the glass component, the titanate, and the ceramic. By including Wollastonite,
The characteristics of the obtained ceramic substrate can be further improved. Further, according to the composition for a ceramic substrate of claim 3, in addition to the effect of the structure of claim 1 or 2, the titanate is CaTiO ₃ , S or S.
rTiO _3, MgTiO _3, or so it composed of at least one of a solid solution of these titanates, by the negative TCC characteristics of these titanates, sintered mixed with a glass component having a positive TCC properties This ensures that the TCC of the substrate can be adjusted within ± 0 to ± 50 ppm / ° C. According to the composition for a ceramic substrate according to claim 4, in addition to the effect of the configuration according to any one of claims 1 to 3, the ceramic is alumina, zirconia, zircon, titania, magnesia, Since it is composed of at least one of mullite, it can not only contribute to the adjustment of the thermal expansion coefficient of the substrate and the provision of heat resistance, but also can reliably reduce the shrinkage rate of the substrate from Ag, Ag-Pd, Au, C.
It can be matched with a conductor material such as u or a resistor material such as RuO ₂ .

[0020]

EXAMPLES Examples of the present invention will be described below. Glass composition is wt%, SiO ₂ is 26, Al ₂ O ₃ is 12, C
aO = 15, MgO = 1, ZnO = 11, TiO ₂ = 10, B
Weigh and mix the raw materials so that ₂ O ₃ is 9 and PbO is 16, and use a platinum furnace to melt at 1450 ° C. for 2 hours with continuous stirring using a platinum stirring rod, and place on a water-cooled roll. The glass flakes were made to flow out. Next, 72 parts by weight, 12 parts by weight, 16 parts by weight and 1 part by weight of the glass flakes, CaTiO ₃ powder as a titanate, alumina powder as a ceramic, and wollastonite (CaO · SiO ₂ ) powder as an external nucleating agent, respectively. Were weighed and pulverized with a ball mill for 24 hours and mixed to obtain the composition of the present invention. After molding the crushed and mixed composition using a pelletizer,
It was 22 kgf / mm ² when the bending strength (three-point bending) was measured according to JIS-R1601 by baking at 900 ° C. for 15 minutes. The coefficient of thermal expansion of a sintered body sample manufactured by the same method was measured using TMA (thermomechanical analyzer) and found to be 67 × 10 ⁻⁷ / ° C.

Further, various binders, plasticizers and solvents were added to the crushed and mixed composition and kneaded to prepare a slurry. This slurry by the doctor blade method,
A green sheet with a thickness of about 0.1 mm was used. Then, 20 layers of this green sheet were stacked and thermocompression bonded, and then baked at 900 ° C. for 15 minutes. When various characteristics of the fired sheet were measured,
Volume resistivity 10 ¹⁵ Ω · cm, dielectric constant 16 and dielectric loss tangent 4
× 10 ^-4 , dielectric breakdown strength 780 kV / cm, TCC 25 ~ 85 ℃
Was +5 ppm / ° C. In addition, A on the green sheet
When the g electrode was printed, thirty sheets of this green sheet were stacked and thermocompression-bonded, and baked at 900 ° C. for 15 minutes, no warpage or peeling was observed. The results are shown in Table 1. Samples were prepared by using the composition according to the other composition of the present invention in the same manner as in the above case, and the results of measuring the physical properties are shown in. In addition, as a comparative example, the results of the measurement in the same manner as above for the compositions not falling within the range of the composition of the present invention are shown in Table 2.
Shown in. In Table 2, the mark "*" indicates that the component is out of the composition range of the present invention.

[0022]

[Table 1]

[0023]

[Table 2]

As is clear from Tables 1 and 2, the characteristics of the materials within the scope of the present invention are TCC of ± 0 to ± 50.
It is in the range of ppm / ° C., and the substrate does not warp or peel (delamination). Other properties are also good. On the other hand, in all cases outside the scope of the present invention, at least the value of TCC is bad, the substrate is warped, or peeling (delamination) occurs.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H05K 3/46 T 6921-4E H 6921-4E

Claims (4)

[Claims] 1. In terms of oxides, SiO ₂ is 20 to 50% by weight, Al ₂ O ₃ is 5 to 20% by weight, CaO is 10 to 20% by weight, BaO is 0 to 10% by weight, and MgO is 0 to 10% by weight, ZnO 0 to 20% by weight, TiO ₂ 5 to 20% by weight, B ₂ O ₃ 5 to 15% by weight, PbO 4 to 25% by weight, and a glass component of 60 to 85% by weight. 5% by weight, titanate
A composition for a ceramic substrate comprising 20% by weight and 10 to 35% by weight of ceramic. 2. The composition for a ceramic substrate according to claim 1, which contains 5% by weight or less of wollastonite with respect to the total amount of the glass component, the titanate and the ceramic. 3. The titanate is CaTiO ₃ , SrTi.
The composition for a ceramic substrate according to claim 1 or 2, comprising O ₃ , MgTiO ₃ , or at least one solid solution of these titanates. 4. The ceramic is alumina, zirconia,
The composition for a ceramic substrate according to claim 1, comprising at least one of zircon, titania, magnesia, and mullite.