JP2001010868A - Composition for ceramic substrate and ceramic circuit part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition which is used for ceramic substrates, can be sintered at a low temperature of <=1,000 deg.C, can simultaneously be sintered together with a conductor circuit consisting mainly of a low resistant metal such as an Ag-based metal or a Cu-based metal, and can give dense sintered compact. SOLUTION: This composition for ceramic substrates comprises 35 to 39 wt.% of glass powder and 61 to 65 wt.% of ceramic powder. Therein, the glass constituting the glass powder 28 to 64 wt.% of SiO2, 0 to 30 wt.% of B2O3, 0 to 30 wt.% of Al2O3, and 36 to 50 wt.% of RO (R is at least one of Mg, Ca, Sr and Ba), and the ceramic powder has an average particle diameter of <1 μm. The composition has good dispersibility between the glass and the ceramic, and can give a dense sintered compact at a sintering temperature of <=1,000 deg.C.

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 a ceramic circuit component, and more particularly to a composition for a ceramic substrate which can be sintered at a low temperature of 1000.degree. The present invention relates to ceramic circuit components such as multilayer integrated circuit components and thick film hybrid circuit components.

[0002]

2. Description of the Related Art At present, the mainstream of ceramic substrates is an alumina substrate. However, in order to obtain an alumina substrate, it must be fired at a high temperature of about 1600 ° C.,
When, for example, a multilayer circuit component is formed using an alumina substrate, a metal having a high melting point must be used for the internal conductor. However, a high melting point metal is generally not suitable as a conductor for a multilayer circuit component whose frequency and speed are increasing because of its high resistance.

[0003] Therefore, Au, Ag, Ag-Pd, Ag-
Attention has been paid to glass-ceramic substrates having a firing temperature of 1000 ° C. or less, which enable use of low-resistance metals such as Pt and Cu as internal conductors, and various developments have been made.

For example, Japanese Patent Publication No. 3-53269 discloses that 50 to 64% of glass powder and 50 to 35% by weight are used.
% Al ₂ O ₃ powder and mixed at 800-1000 ° C.
A low-temperature sintered ceramic substrate that can be sintered at is described.

[0005]

However, in the case of a substrate having the above-mentioned glass charge amount of 50% or more, the crystal ratio in the fired substrate is low, and the reliability of the mechanical characteristics of the substrate is low. There is a problem.

Accordingly, an object of the present invention is to provide a composition for a ceramic substrate and a ceramic circuit component formed using the same, which can solve the above-mentioned problems.

More specifically, according to the present invention, A
Provided is a composition for a ceramic substrate for an electronic circuit having a firing temperature of 1000 ° C. or lower, which enables a low-resistance metal such as u, Ag, Ag-Pd, Ag-Pt, or Cu to be used as an internal conductor. According to the ceramic substrate obtained by firing this composition, it is possible to realize a transverse rupture strength exceeding 350 MPa.

[0008]

In order to solve the above-mentioned technical problems, the composition for a ceramic substrate according to the present invention comprises 35 to 39% by weight of glass powder and 61 to 65% by weight of ceramic powder. Each of the glasses constituting the glass powder contains 28 to 64% by weight of SiO ₂ ,
0-30 wt% of B ₂ O _3, 0 to 30 wt% of Al ₂ O
₃ and 36-50% by weight of RO (where R is M
at least one selected from g, Ca, Sr and Ba
), And the average particle size of the ceramic powder is 1
It is characterized by being less than μm.

As described above, in the composition for a ceramic substrate according to the present invention, the particle size of the ceramic powder is reduced while the proportion of the ceramic is increased, as compared with the case of the above-described prior art, whereby the composition is improved. The purpose is to increase the mechanical strength of a ceramic substrate obtained by sintering the composition.

Generally, the driving force for sintering in a composite material consisting of glass and ceramic is provided by softening and viscous flow of glass. Therefore, when the proportion of ceramic is increased and the proportion of glass is decreased, the glass around the ceramic particles becomes insufficient, and the sinterability and mechanical strength decrease.

According to the present invention, not only is the ratio of ceramic increased, but also the average particle size of the ceramic powder is made smaller than 1 μm, thereby increasing the molding density of the composite material composed of glass and ceramic and preventing the sinterability from lowering. can do. If the relative density after sintering is substantially the same, the mechanical strength is increased as the proportion of ceramic increases.

In the present invention, the glass constituting the glass powder is SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ and RO
With respect to 100 parts by weight of the total of the above, further contains at least 5 parts by weight of an oxide of at least one alkali metal selected from Li ₂ O, K ₂ O and Na ₂ O, TiO ₂ , ZrO ₂ , Cr ₂ O ₃ , C
At least one compound selected from aF ₂ and CuO may be further contained at a content of 5 parts by weight or less.

Preferably, the ceramic powder contains an alumina powder.

The present invention also provides a ceramic circuit component comprising: a substrate obtained by molding and firing the composition for a ceramic substrate as described above; and a conductor circuit formed in connection with the substrate. Is also directed.

In this ceramic circuit component, the conductor circuit preferably contains at least one metal selected from Ag, Au and Cu as a main component.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composition for a ceramic substrate which can be sintered at a low temperature and contains a glass powder and a ceramic powder.
9%, and 61-65% of ceramic powder, respectively. The reason for limiting to such a content ratio is as follows.

If the glass powder content is less than 35% and the ceramic powder content is more than 65%, the glass cannot sufficiently cover the ceramic particles, and a dense sintered body cannot be obtained.
Conversely, if the glass powder content is more than 39% and the ceramic powder content is less than 61%, the mechanical strength is 350M because the glass is dominant even if the obtained sintered body is dense.
Below Pa, the reliability of the mechanical properties of the ceramic substrate is insufficient.

In the present invention, the glass constituting the glass powder contains 28 to 64% by weight of SiO ₂ , 0 to 3% by weight.
0 wt% of B ₂ O _3, 0~30 wt% Al ₂ O _3, and 36 to 50 wt% of RO (wherein, R is, Mg, C
a, Sr and Ba). The reason for limiting the composition of such glass is as follows.

SiO ₂ forms the skeleton of glass. When the content of SiO ₂ is less than 28% by weight, the softening point of the glass becomes too low, and the heat resistance of the obtained ceramic substrate deteriorates. On the other hand, if it exceeds 64% by weight,
The softening point of the glass is too high, so that firing at a temperature of 1000 ° C. or less cannot be applied to obtain a ceramic substrate, and as a result, Au, Ag, Cu, etc. are used as conductive components for forming a conductive circuit. become unable.

B ₂ O ₃ has the effect of lowering the firing temperature for obtaining a ceramic substrate, but if its content exceeds 30% by weight, water resistance and chemical resistance deteriorate, and In a high-temperature, high-humidity environment, the quality of the ceramic substrate may be altered, and the softening point of the glass may be too low, thereby deteriorating the heat resistance of the obtained ceramic substrate.

Al ₂ O ₃ stabilizes the glass structure,
It has the effect of improving the heat resistance of the obtained ceramic substrate, but if its content exceeds 30% by weight, the softening and fluidity of the glass deteriorate, and the ceramic substrate is sintered at 1000 ° C. or lower. Therefore, the crystallization of glass is hindered, and characteristics such as high mechanical strength and low loss cannot be realized.

RO has the effect of promoting the softening and fluidity of glass, but its content is 36% by weight.
If it is less, the softening point of the glass becomes too high, so that firing at a temperature of 1000 ° C. or less cannot be applied to obtain a ceramic substrate. As a result, Au, Ag, Cu, etc. Can no longer be used. On the other hand, if the content of RO exceeds 50% by weight, the glass structure becomes unstable, and it becomes impossible to obtain glass of stable quality.

In the production of glass having the above composition, if it is desired to further promote softening and fluidity, use Li
_At least one selected from ₂ O, K ₂ O and Na ₂ O
Oxide species of the alkali metal, as described above, B ₂ O
₃ , SiO ₂ , Al ₂ O ₃ and RO may be contained at a content of 5 parts by weight or less based on 100 parts by weight in total. If the content of these alkali metal oxides exceeds 5 parts by weight, the electrical insulation of the glass decreases, so that the insulation resistance of the sintered ceramic substrate decreases.

Further, the crystallization of the glass during the firing process can be improved.
Promotes high mechanical strength of the obtained ceramic substrate,
To promote low loss, TiO_Two, ZrO_Two, Cr_TwoO
_Three, CaF_TwoAnd at least one selected from CuO
With the compound of the aforementioned B_TwoO _Three, SiO_Two, Al_TwoO_Three
5 parts by weight or less based on 100 parts by weight of RO and RO
May be contained. In addition, these
When the content of the compound exceeds 5 parts by weight, the dielectric constant of the glass becomes
The dielectric constant of the ceramic substrate after sintering
There is a problem that it becomes too much.

The ceramic powder contained in the composition for a ceramic substrate according to the present invention has an average particle diameter of 1 μm.
Must be less than. The average particle size of the ceramic powder is 1
If it is more than μm, the dispersibility with glass is poor and the molding density is low, so that the sinterability is low and the sintered body obtained by firing, that is, the ceramic substrate has a mechanical strength of 350 MPa or less.

As the ceramic powder, for example, alumina powder can be advantageously used.

The composition for a ceramic substrate as described above is used to produce a ceramic circuit component comprising a substrate obtained by molding and firing the same, and a conductor circuit formed in connection with the substrate. It is advantageously used for:

FIG. 1 is an example of the above-described ceramic circuit component, and is a cross-sectional view schematically showing a ceramic multilayer circuit component 1 according to an embodiment of the present invention. The ceramic multilayer circuit component 1 is, roughly speaking, a ceramic substrate 2
And a conductor circuit 3 formed inside and / or on the surface of the ceramic substrate 2.

The ceramic substrate 2 is obtained by firing a ceramic molded body obtained by laminating a plurality of green sheets containing the composition for a ceramic substrate having the above-described composition. It comprises a plurality of ceramic layers 4 resulting from the firing of each of the green sheets.

The conductor circuit 3 is formed, for example, by simultaneously firing a conductive paste containing a conductive component mainly composed of at least one metal selected from Ag, Au and Cu, with the above-mentioned ceramic molded body. It was done. The conductor circuit 3 includes, for example, external conductors 5, 6, and 7 formed on the surface of the ceramic substrate 2, and includes the internal conductor 8 formed on the inside of the ceramic substrate 2, for example. , 9,10,11
And via hole connection part 1
3, 14, 15, 16, 17, 18, and 19, and the like.

The internal conductors 8 and 9 are opposed to each other via a specific ceramic layer 4 to form a capacitor section 20. Also, via-hole connection portions 16 to 19 and internal conductor 1
0 to 12 are connected alternately and sequentially to form the inductor unit 21.

[0032]

EXPERIMENTAL EXAMPLES Hereinafter, the composition for a ceramic substrate according to the present invention will be described more specifically based on experimental examples.

Table 1 shows the composition of the composition for a ceramic substrate produced in this experimental example.

[0034]

[Table 1]

As shown in Table 1, alumina powder having a particle diameter of 0.7 to 1.4 μm and forsterite powder having a particle diameter of 0.9 μm were prepared as ceramic powders.

On the other hand, as a glass constituting the glass powder, a mixture of oxides or carbonates as starting materials weighed so as to have a glass composition shown in Table 1 was used in the range of 1300 to 17
After being melted and vitrified at a temperature of 00 ° C., the glass was quenched in water, and the quenched glass was pulverized until the particle diameter became 1.4 μm, thereby producing a glass powder.

In Table 1, the starting material Si
O ₂ , B ₂ O ₃ , Al ₂ O ₃ , and MgO / CaO /
For SrO / BaO, the composition ratio between them is shown in units of “% by weight”, and for “other” starting materials such as Li ₂ O, SiO ₂ , B ₂ O ₃ , Al
It is shown in terms of "parts by weight" with respect to 100 parts by weight of the total amount of ₂ O ₃ and MgO / CaO / SrO / BaO.

Next, ceramic powders of various particle sizes prepared as described above and glass powders of various compositions were prepared at various ratios as shown in Table 1 and mixed with a solvent (ethanol / toluene). And a dispersant (sorbitan ester), and the mixture was dispersed. A binder (butyral resin) and a plasticizer (dioctyl phthalate) were added and mixed to obtain a slurry. Then, by applying a doctor blade method to the slurry,
I got a green sheet.

Next, based on the green sheets of the respective samples obtained as described above, several types of samples were prepared, and the “bending strength”, “dielectric constant”,
"Q", "insulation resistance", and "appearance of substrate" were each evaluated.

[0040]

[Table 2]

First, a predetermined number of green sheets for each sample are laminated, cut into a predetermined size, and then fired at a firing temperature shown in Table 2 to obtain a sintered body. The dimensions were 36 mm, width 4 mm and thickness 3 mm. The sintered body according to each sample obtained in this manner was subjected to the JIS standard (JIS R160
The bending strength (three-point bending) was measured according to 1).

Further, a ceramic multilayer circuit component 1 as shown in FIG. 1 was manufactured using the green sheets of the respective samples. That is, a hole is formed in the green sheet, and an Ag-based paste is filled in these holes to form via-hole connection portions 13 to 1.
9 is formed, and an Ag-based paste is screen-printed to form a predetermined pattern of the outer conductors 5 to 7 and the inner conductors 8 to
No. 12 was formed. Thereafter, a predetermined number of these green sheets to become the ceramic layers 4 were laminated and pressed. Next, firing was performed at a firing temperature shown in Table 2 in air to produce a ceramic multilayer circuit component 1.

In the ceramic multilayer circuit component 1 thus obtained, a frequency of 1M is applied between the outer conductors 5 and 6.
A voltage of Hz was applied to measure the capacitance and Q of the capacitor unit 20 to calculate the dielectric constant (ε _r ). Further, a voltage of 100 V was applied between the outer conductors 5 and 6, and the insulation resistance was measured. The dielectric constant, Q and insulation resistance are shown in Table 2.

Further, the appearance of the above-mentioned ceramic multilayer circuit component 1 was observed, and whether or not glass had flowed out to the surface of the ceramic substrate 2 was evaluated.

In Tables 1 and 2, Samples 1 to 19
Corresponds to Examples within the scope of the present invention, and
No. 4 corresponds to a comparative example outside the scope of the present invention.

Referring to Table 2, samples 1 to 3 as examples were used.
According to No. 19, when the firing temperature is 1000 ° C. or less, 3
When the flexural strength exceeds 50 MPa, the dielectric constant is 7.8 to 8.8, Q is 1400 to 2000, and the insulation resistance exceeds 10 ¹⁰ Ω · cm, which is sufficient for a ceramic substrate in a ceramic circuit component. The characteristics were shown.

In particular, Sample 1 using a mixed powder of alumina powder and forsterite powder as ceramic powder
Also in 1, the firing temperature is 1000 ° C. or less and 3
The flexural strength exceeds 50 MPa, the dielectric constant is 7.8, Q is 1400, and the insulation resistance is 10 ¹⁰ Ω · c.
m.

In the glass constituting the glass powder,
In Li ₂ O, samples 12 to 14 which contains the K ₂ O or Na ₂ alkali metal oxides such as O, since the softening temperature of the glass decreases, the same except that it does not contain alkali metal Compared with Sample 9 having a glass composition, it was confirmed that firing could be performed at the same temperature despite the small amount of glass added, and the bending strength was slightly increased.

Further, TiO ₂ , ZrO ₂ ,
Sample 1 containing Cr ₂ O ₃ , CaF ₂ or CuO
5 to 19, not shown in Table 2, compared to Sample 1 having similar glass composition and similar glass / ceramic ratio except that these compounds were not included, It was confirmed that crystallization was promoted. Further, due to the promotion of the crystallization, the transverse rupture strength and the Q value were higher than those of the sample 1.

On the other hand, Sample 20 as a comparative example
According to Nos. 21 and 21, the sintering density was high because the proportion of alumina powder as the ceramic powder was small, but the transverse rupture strength was 350 MPa or less.

According to Samples 22 and 23, since the proportion of alumina powder as the ceramic powder was large, the molding density and, consequently, the sintering density were low, and the bending strength was 350%.
MPa or less. In particular, when the ratio of alumina powder is 70
Sample 2 significantly exceeding 65% by weight, such as% by weight
In No. 3, since the density of the obtained ceramic substrate was further reduced, only a low Q was obtained.

According to Samples 24 to 26, since the particle size of the alumina powder as the ceramic powder is large, the molding density and, consequently, the sintering density are low, and the transverse rupture strength is 350M.
Pa or less. In particular, when the particle size of the alumina powder is 1.2
In Samples 25 and 26 having a size of not less than μm, Q was further reduced because the density of the ceramic substrate was further reduced.

In sample 27, SiO _{2 in} the glass was used.
Due to the small amount, the softening point of the glass is low and the firing temperature is 8
Even at a low temperature of 00 ° C., the glass flowed out of the substrate surface.

[0054] On the other hand, in Sample 28, SiO in the glass ₂
Due to the large amount, the softening point of the glass was increased, and even when the firing temperature was increased to 1000 ° C., the sintering density was low and the bending strength was 350 MPa or less.

In the sample 29, B ₂ O ₃
Due to the large amount, the softening point of the glass is low and the firing temperature is 80
Even at as low as 0 ° C., the glass flowed out of the substrate surface.

In sample 30, Al ₂ O in glass
_{Since the} amount was large, the softening point of the glass became high, and even when the firing temperature was increased to 1000 ° C., the sintering density was low and the transverse rupture strength was 350 MPa or less.

In sample 31, since the content of the alkaline earth metal oxide, ie, RO, in the glass is small, the softening point of the glass is high, and the sintering density is low even when the firing temperature is as high as 1000 ° C. Also, the bending strength became 350 MPa or less.

On the other hand, in Sample 32, since the content of the alkaline earth metal oxide, ie, RO, in the glass was large, the structure of the glass was unstable, and a glass of stable quality could not be obtained. Therefore, the sinterability of the substrate varies greatly,
The transverse rupture strength was 350 MPa or less.

In sample 33, K in glass_TwoO's
Due to high content, insulation resistance is 10 ⁹Ω · cm and low
There was a problem in the reliability of the substrate.

In Sample 34, since the content of CuO in the glass was large, the dielectric constant was as high as 9.0.

[0061]

As described above, according to the composition for a ceramic substrate of the present invention, 3 parts by weight of glass powder is used.
Despite containing 5 to 39% and ceramic powder of 61 to 65%, and increasing the proportion of ceramic, the particle size of the ceramic powder is set to less than 1 μm, whereby the glass and the ceramic are mixed. it is possible to make dispersibility good, the glass constituting the glass powder, 28 to 64 wt% of SiO _2, 0 to 30 wt% of B ₂ O _3, 0 to 30 wt% Al ₂ O _3, And 36-
Since it has a composition containing 50% by weight of RO (where R is at least one selected from Mg, Ca, Sr and Ba), a dense sintered body, A ceramic substrate can be obtained. In addition to the denseness of such a sintered body, an increase in the proportion of ceramic also contributes to increasing the mechanical strength of a ceramic substrate obtained by firing the composition.

Further, as described above, according to the composition for a ceramic substrate according to the present invention, a firing temperature of 1000 ° C. or less can be applied, so that a low-resistance metal such as an Ag-based or Cu-based metal is mainly used. A ceramic circuit component having a conductor circuit containing as a component can be obtained without problems by co-firing, and therefore, it is easy to obtain a ceramic circuit component having a ceramic substrate having a low dielectric constant, a high Q, and a high mechanical strength. become.

In the composition for a ceramic substrate according to the present invention, the glass constituting the glass powder is Li ₂ O, K
An oxide of at least one alkali metal selected from ₂ O and _{Na 2 O, SiO 2, B} 2 O 3, Al 2 O 3
And a total content of RO of 5 parts by weight or less relative to 100 parts by weight promotes softening and fluidity of the glass, and reduces the content of glass in the ceramic substrate composition. Also, the sintering temperature can be kept relatively low.

In the composition for a ceramic substrate according to the present invention, the glass constituting the glass powder is TiO.
₂ , at least one compound selected from the group consisting of ZrO ₂ , Cr ₂ O ₃ , CaF ₂ and CuO is converted to SiO ₂ , B ₂ O
₃ , when the content of Al ₂ O ₃ and RO is not more than 5 parts by weight based on 100 parts by weight of the total amount, crystallization of glass is promoted, and further high mechanical strength of the obtained ceramic substrate is obtained. And lower loss can be contributed.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a ceramic multilayer circuit component 1 according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic multilayer circuit component 2 Ceramic board 3 Conductor circuit 4 Ceramic layer 5-7 External conductor 8-12 Internal conductor 13-19 Via hole connection part

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/46 H01L 23/14 C (72) Inventor Osamu Yokokura 2-26-10 Tenjin, Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (reference) 4G030 AA36 BA09 BA20 GA11 GA22 GA27 PA07 4G062 AA09 AA15 BB01 BB05 DA04 DA05 DA06 DB01 DB02 DB03 DB04 DC01 DC02 DC03 DC04 DD01 DE01 DF01 EA01 EA02 EA03 EA10 EB02 EC03 EB02 EC03 ED04 ED05 EE01 EE02 EE03 EE04 EE05 EF01 EF02 EF03 EF04 EF05 EG01 EG02 EG03 EG04 EG05 FA01 FA10 FB01 FB02 FB03 FC01 FC02 FC03 FD01 FE01 FF01 FG01 FH01 FJ01 F03 H01 GE01H01 GE01H01 H01 GE01H01 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM28 NN26 NN32 NN33 PP03 5E346 AA12 AA15 CC18 CC32 CC38 CC3 9 EE24 EE27 EE29 GG04 GG09 HH11

Claims (6)

[Claims] 1. A glass powder in a weight ratio of 35 to 39.
%, And 61-65% of ceramic powder, respectively, and the glass constituting the glass powder is 28-64% by weight.
Of SiO ₂ , 0 to 30% by weight of B ₂ O ₃ , 0 to 30% by weight of Al ₂ O ₃ , and 36 to 50% by weight of RO (where R is selected from Mg, Ca, Sr and Ba) The composition for ceramic substrates has a composition containing at least one of the above-mentioned ceramic powders, and wherein the average particle size of the ceramic powder is less than 1 μm. 2. The glass constituting the glass powder is L
i_TwoO, K_TwoO and Na_TwoAt least selected from O
The one kind of alkali metal oxide is converted to the SiO 2 _Two, B_TwoO
_Three, Al_TwoO_ThreeAnd 100 parts by weight of RO
Claim 1 wherein the content is less than 5 parts by weight.
The composition for a ceramic substrate according to the above. 3. The glass constituting the glass powder is T
iO ₂ , ZrO ₂ , Cr ₂ O ₃ , CaF ₂ and CuO
At least one compound selected from the group consisting of Si
Total amount of O ₂ , B ₂ O ₃ , Al ₂ O ₃ and RO is 100
The composition for a ceramic substrate according to claim 1, wherein the composition is contained in an amount of 5 parts by weight or less based on parts by weight. 4. The composition for a ceramic substrate according to claim 1, wherein the ceramic powder includes an alumina powder. 5. A ceramic comprising: a substrate obtained by molding and firing the composition for a ceramic substrate according to claim 1; and a conductor circuit formed in relation to the substrate. Circuit components. 6. The conductor circuit according to claim 6, wherein said conductor circuit comprises Ag, Au and C.
The ceramic circuit component according to claim 5, comprising at least one metal selected from u as a main component.