JP3217502B2 - Cordierite powder and method for producing porcelain - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of sintering at a temperature of about 1000.degree. C., and can be co-fired with a low-resistance conductor such as Au, Ag, Cu, and the like. Is related to a large cordierite powder and a method for producing the porcelain.

[0002]

2. Description of the Related Art Conventionally, an alumina substrate has been used as an electronic circuit board. However, as the speed of a semiconductor device increases, a signal propagation delay of a wiring connecting the devices cannot be ignored, and a large dielectric constant (1 MHz) is required. The relative dielectric constant at is 9.
5) The alumina substrate is said to be unsuitable for high-frequency circuits and the like. In other words, it is desired that the dielectric constant of the substrate material is low in order to propagate signals at high speed, and the thermal expansion coefficient is close to that of silicon so that the element can be mounted directly on the substrate in a naked state, and It is required that sintering be performed at a low temperature of 1000 ° C. or less so that the electrode material having a low melting point such as Au, Ag, and Cu can be co-fired.

Incidentally, the chemical formula 2MgO.2Al ₂ O ₃
・ Indicated by 5SiO ₂ , 13.8 wt% of MgO, Al
Cordierite having a composition of 34.9 wt% of ₂ O _{3 and} 51.3 wt% of SiO ₂ has a melting point of 1455.
° C, low dielectric constant (relative dielectric constant at 1 MHz is 5.0), and low coefficient of thermal expansion (15 × 10 ^-7 / 20 to 400 ° C).
C) crystalline material. Cordierite is also a useful material for electronic circuit packages because of its excellent electrical insulation.

[0004] However, cordierite has a sinterable temperature range of from the melting point (1455 ° C) to within 25 ° C, and therefore, sintering is difficult without a sintering aid. Therefore, a ceramic composite of cordierite and glass is made of Au, Ag,
Attention has been paid because it can be co-fired with a conductor such as Cu. That is, a mixture of cordierite and glass having a specific composition is melted at a temperature of 1500 ° C. or more to produce a homogeneous glass, and then quenched and pulverized into fine glass powder, and then TiO ₂ , ZrO ₂ , P ₂ O ₅ , S
A nucleating agent such as nO ₂ is added and formed into a sheet.
It has been proposed to obtain a ceramic composite made of crystalline cordierite by firing at a temperature of about 00 ° C.

However, this is not preferable as an electronic circuit board because of its low mechanical strength, high dielectric constant, and high thermal expansion coefficient. It is also known to obtain high purity and crystalline cordierite powder by a sol-gel method using a metal alkoxide, which can be sintered without a sintering aid, If it is not the temperature of sintering, A
It cannot be co-fired with electrode materials having a low melting point, such as u, Ag, and Cu.

[0006] Under these circumstances, research and development have been earnestly promoted.
For example, SiO_TwoIs 40 to 58% by weight, A
l_TwoO_Three17-35% by weight, MgO 10-20% by weight
% ZrO_Two1 to 10% by weight
1 to 10% by weight of B_TwoO _Three, 1-12% by weight P_Two
O_Five, At least one selected from 1 to 8% by weight of BaO
Add, melt, cool, pulverize, pulverize this
Of cordierite porcelain for molding and sintering
It has been proposed (JP-B-51-37655).

In addition, SiO_Two, Al_TwoO_ThreeAnd MgO
By firing a molded body of glass composition powder as a component
A glass sintered body, wherein the composition of the glass composition is Si
O_TwoIs 45 to 60% by weight, Al_TwoO_ThreeIs 10-25 weight
%, 25-40% by weight of MgO, TiO_Two, ZrO_Two,
SnO_Two, P_TwoO_Three, ZnO, As_TwoO_ThreeAnd MoO _Three
At least one nucleating agent selected from the group consisting of
Glass sintered body characterized in that the proportion is not more than% by weight
Has been proposed (JP-A-62-252340).
You.

[0008]

However, in the cordierite porcelain disclosed in the first proposal (Japanese Patent Publication No. 51-37655), impurities cannot be avoided and the sintering temperature is relatively high. Has a problem that the strength is insufficient. Further, the second proposal (Japanese Patent Laid-Open No. 62-252340)
Publication) can be co-fired with a low-resistance conductive metal such as silver, silver-palladium, or gold. Even when used as a multilayer wiring board material, there is no fear of insulation deterioration due to the migration phenomenon and the dielectric constant is high. Although it is vomited when low features are exhibited, there is a problem that the strength characteristics are not sufficient.

An object of the present invention is to provide, for example, a circuit board having sufficient mechanical strength, a coefficient of thermal expansion close to that of silicon, a low dielectric constant, and a low temperature (a temperature of about 1000 ° C.). An object of the present invention is to provide a cordierite powder that can be fired and a porcelain thereof.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
l ₂ O ₃ minutes 25 to 38 wt%, SiO ₂ minutes 45-5
8 wt%, and cordierite composition sol adjustment step of adjusting the cordierite composition sol by mixing the alumina sol and silica sol and water soluble magnesium salt to MgO content at a ratio of 12 to 20 wt%, the Kodie Light
Hou in terms _of B ₂ O ₃ in the sol obtained by the composition sol adjustment step
Acid added to cordierite at 0.05 to 10% by weight
And a gelling step of gelling,
Calcining the gelled product at a temperature of 850-950 ° C
It is achieved by the method for producing a cordierite powder characterized by comprising a degree.

The object of the present invention is that the content of Al ₂ O ₃ is 25 to 38% by weight, the content of SiO ₂ is 45 to 58% by weight,
In a cordierite composition sol obtained by mixing an alumina sol, a silica sol, and a water-soluble magnesium salt such that the gO content is 12 to 20% by weight, boric acid is added in an amount of 0.05 to 10% by weight in terms of B ₂ O _3. 800 of added slurry
It is achieved by a method for producing cordierite powder, which comprises spray roasting at a temperature of about 1200 ° C.

Further, the object of the present invention is that the content of Al ₂ O ₃ is 25 to 38% by weight, the content of SiO ₂ is 45 to 58% by weight,
a cordierite composition sol adjustment step of adjusting the cordierite composition sol gO content by mixing the alumina sol and silica sol and water soluble magnesium salt to be a proportion of 12 to 20 wt%, the cordierite composition sol adjustment
Boric acid is converted into B ₂ O ₃ equivalent to the sol obtained in the process.
Adds 0.05 to 10% by weight with respect to erite to gel
Gelation step, and the gel obtained in the gelation step
A calcining step of calcining, and a calcined product obtained in the calcining step.
After crushing and molding, sintering at a temperature of 950 to 1050 ° C
And a sintering step .

The object of the present invention is that the content of Al ₂ O ₃ is 25 to 38% by weight, the content of SiO ₂ is 45 to 58% by weight,
In a cordierite composition sol obtained by mixing an alumina sol, a silica sol, and a water-soluble magnesium salt such that the gO content is 12 to 20% by weight, boric acid is added in an amount of 0.05 to 10% by weight in terms of B ₂ O _3. Spray roasting the added slurry, and molding the powder obtained in the above step,
It is achieved by the method for producing a cordierite ceramic, characterized in that <br/> comprising a sintering step of sintering at a temperature of 0-1,050 ° C..

In the present invention, the powder of the sintering raw material is preferably spherical. That is, by using a spherical one, the fluidity of the slurry during casting during molding is good, the green density is high, and
Shrinkage during sintering is isotropic and uniform, and a highly accurate product with little distortion or variation can be obtained.

Hereinafter, the present invention will be described in detail. As the alumina source of the alumina sol used in the present invention, non-hydrated alumina such as amorphous alumina or γ-alumina, δ-alumina, θ-alumina, κ-alumina, or gibbsite, payalite, northlandite, bauxite, Hydrated alumina such as boehmite, diamondspore, dootite, or aluminum salt such as aluminum nitrate or aluminum sulfate can be used, and a liquid in which such an alumina source is dispersed in water or an inert solvent is used to produce the ceramic powder of the present invention. Used for
In particular, it is preferably obtained by heating an aqueous dispersion of γ-alumina or boehmite to 80 ° C. or higher, adding an appropriate amount of an inorganic acid such as nitric acid or hydrochloric acid, or acetic acid, or an organic acid such as formic acid, and peptizing. A boehmite sol solution is used.

As the silica source of the silica sol, colloidal silica (Si (OH) ₄ ), fume silica (SiO
₂ ), silica polymer (for example, TEOS), silicate (Na ₂ O.SiO ₂ , H ₂ SiO ₃ ), etc. can be used, and there is no particular limitation as long as the silica sol is generated by hydrolysis. . As the magnesium salt, a water-soluble salt such as magnesium nitrate, magnesium chloride, magnesium carbonate, and magnesium hydroxide is desirable.

As the boron oxide (B ₂ O ₃ ) source, boric acid (H ₃ BO ₃ ), aluminum borate, magnesium borate, and the like can be preferably used. In producing cordierite porcelain, the sol-gel method was used.
This is because the raw materials are uniformly mixed and impurities are less mixed than in the case where the glass is crushed, whereby a high-quality product is obtained.

The cordierite composition sol is prepared, for example, by adding a water-soluble magnesium salt to a boehmite sol and a silica sol at a ratio of the theoretical composition of cordierite. Next, the gelation of the cordierite composition sol obtained as described above is performed,
It is important to use boric acid for this gelation. That is, the cordierite-boron-based material obtained by adding boric acid, heating and drying to be gelled can be fired at a low temperature and promote crystallization. In particular,
When the amount of boric acid is adjusted to 0.5 to 10% by weight with respect to cordierite in terms of B ₂ O ₃ , the above-mentioned features are remarkably exhibited.

The gelled material thus obtained is calcined. In this calcining step, 850 to 9
Crystallization is preferably performed by calcination at 50 ° C.
That is, cordierite calcined under such conditions has a remarkable strength. It is preferable that the cordierite powder obtained as described above is calcined at a temperature of 950 to 1050 ° C. If the temperature is too low below 950 ° C, sintering is insufficient and strength is not sufficient. ,
If the temperature is higher than 1050 ° C., the number of pores increases, the density decreases, and the strength decreases.

Also, boric acid is added to the cordierite composition sol in an amount of 0.05 to 10 in terms of B ₂ O ₃ without using the sol-gel method.
Spraying the slurry with weight percent added in a heating furnace and roasting it to produce a spherical powder, adding a binder and various additives to it and producing a sheet (including a plate-like one) by press molding Or green sheet by extrusion molding, doctor blade method or calender roll method, etc., and cutting, punching, conductor printing, laminating etc. , A porcelain with high strength can be obtained. That is, a spherical powder can be produced by spraying and roasting the composite sol without going through the gelling step, and a porcelain with higher strength can be obtained.

At this time, it is preferable to prepare the spherical powder finely because the finer the spherical powder can be sintered at a lower temperature. For example, 10 μm or less, preferably 5 μm
m or less. This preparation can be performed by controlling the spraying conditions. And although only such a spherical powder may be used, a spherical powder and a non-spherical powder (preferably 40% by weight or less) are mixed, or a part of the spherical powder is pulverized, and this non-spherical powder ( (Preferably 40% by weight or less) may be molded and fired.

The roasting temperature in the spraying / roasting step is 800 to 1200 ° C., preferably 900 to 1100.
° C. That is, if the roasting temperature is too low, the moldability is poor, and if it is too high, the particles fuse together and aggregates are easily formed. The sintering temperature in the sintering process is 9
The temperature is preferably from 50 to 1050C. That is, if the firing temperature is too low, sintering does not proceed sufficiently and the strength tends to decrease. Conversely, if the firing temperature is too high, the pores increase in the sintered body, the density decreases, and the strength decreases. This is because it will decrease.

[0023]

【Example】

[Examples 1 to 4, Comparative Examples 1 to 4] First, alumina sol (boehmite sol) as a starting sol raw material was prepared by dispersing a commercially available boehmite powder in a 0.2N nitric acid aqueous solution,
Obtained by heating at 3 ° C. for 3 hours.

Silica sol is commercially available colloidal silica powder
Is dispersed in a 0.2N aqueous nitric acid solution, and the pH is adjusted to 3 at room temperature.
Lower and adjusted. This alumina sol and silica sol
On the other hand, the aqueous solution of magnesium nitrate was_TwoO _Three: SiO
_Two: MgO in a ratio shown in Table 1 below
By mixing, a cordierite composition sol was prepared.

The cordierite composition sol is treated with H
_An aqueous solution of ₃ BO ₃ was added at the ratio shown in Table 1, and dried by heating to gel. The gelled material thus obtained was calcined at 850 to 950 ° C. to be crystallized. Then, this powder was uniaxially formed at a pressure of 1 t / cm ² , and the following table was used.
It was fired at the temperature shown in Fig. 2 to obtain cordierite-based porcelain.

Examples 5 to 8 and Comparative Examples 5 to 7 Alumina sol (boehmite sol) as a starting sol material was prepared by dispersing a commercially available boehmite powder in a 0.2N aqueous nitric acid solution at 80 ° C. under normal pressure for 3 hours. Obtained by heating. The silica sol was prepared by dispersing a commercially available colloidal silica powder in a 0.2N nitric acid aqueous solution and adjusting the pH to below 3 at room temperature.

The alumina sol and the silica sol are mixed with nitric acid.
Aqueous solution of magnesium silicate_TwoO _Three: SiO_Two: Mg
O is mixed so as to have a ratio shown in Table 1 below,
Cordierite composition sol was prepared. This cordier
H in light composition sol_ThreeBO_ThreeRatio of aqueous solution shown in Table-1
The sol that was added and mixed in and stabilized at pH 1 to 4 was added.
Prepared.

Thereafter, the mixture was immediately sprayed into a calciner heated to 800 to 1300 ° C. to obtain a spherical powder. Then, this powder was uniaxially formed at a pressure of 1 t / cm ² , and the following Table 2 was used.
Was fired at the temperature shown in Table 1 to obtain cordierite-based porcelain. Table 1 Composition (parts by weight) Firing temperature Al ₂ O ₃ SiO ₂ MgOB ₂ O ₃ (° C.) Example 1 28.0 56.5 13.5 2.0 950 Example 2 30.9 52.1 15.0 2.0 850 Example 3 33.0 50.0 13.0 4.0 900 Example 4 33.9 52.1 13.0 1.0 950 Example 5 35.0 48.5 15. 0 1.5 800 Example 6 30.0 49.5 17.5 3.0 1000 Example 7 26.0 50.5 16.5 7.0 1100 Example 8 30.0 55.5 13.5 1 0.0 1200 Comparative Example 1 21.0 64.5 13.5 1.0 1100 Comparative Example 2 40.0 45.5 13.5 1.0 1000 Comparative Example 3 37.5 40.0 22.50 1300 Compare Example 4 38.0 40.0 10.0 12.0 1100 Comparative Example 5 22.5 57.5 20.0 0 1100 Comparative Example 6 32.5 58.5 8.0 1.0 1200 Comparative Example 7 21.5 57.5 18.0 3.0 1100 [Characteristics] The obtained cordierite-based porcelain was examined for its coefficient of thermal expansion, three-point bending strength, relative dielectric constant, and crystal phase. The results are shown in Table 2.

Table 2 Coefficient of thermal expansion Three-point bending strength Relative permittivity Crystal phase Sintering temperature (/ ° C.) (MPa) (1 MHz) (° C.) Example 1 31 × 10 ⁻⁷ 250 5.1 C 950 Example 2 30 × 10 ⁻⁷ 250 5.2 C 950 Example 3 29 × 10 ⁻⁷ 230 5.3 C 1000 Example 4 32 × 10 ⁻⁷ 230 5.2 C 1050 Example 5 25 × 10 ⁻⁷ 200 5 0.0 C 1000 Example 6 28 × 10 ⁻⁷ 200 5.2 C 950 Example 7 35 × 10 ⁻⁷ 190 5.4 C 950 Example 8 36 × 10 ⁻⁷ 230 5.2 C 1000 Comparative Example 150 × 10 ⁻⁷ 180 6.6 C + SP 1200 Comparative Example 2 48 × 10 ⁻⁷ 150 7.2 C + AB 1100 Comparative Example 3 45 × 10 ⁻⁷ 180 6.5 C + SP 1400 Comparative Example 4 50 × 10 ⁻⁷ 180 6.5 C + SP + AB 1200 Comparative Examples ^{5 60 × 10 -7 170 5.5 C} + CR 1200 Comparative Example ^{6 70 × 10 -7 180 8.0 GA} + SP 1500 Comparative Example ^{7 60 × 10 -7 200 7.5 MS} + C + CR 1300 * C is 2MgO · 2Al ₂ O ₃ · 5SiO ₂ (cordierite) SP 2Al is · MgO ₂ O ₃ AB is _{Al 2 O 3 · B 2 O} 3 CR are SiO ₂ (cristobalite) MS is MgO · SiO ₂ GA is γ-Al ₂ O ₃ ( Gamma alumina)

[0030]

According to the present invention, it is uniform, contains few impurities, has excellent mechanical strength, has a thermal expansion coefficient close to that of silicon, has a low dielectric constant, and can be sintered at a low temperature.
For example, cordierite porcelain that can use Au, Ag, Cu, or the like as a wiring material can be provided at low cost.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuko Haga 5310 Mikajiri, Kagoya-shi, Saitama Chichibu Cement Co., Ltd. Fine Ceramics Headquarters (56) References JP-A-4-338164 (JP, A) JP-A-2-116613 (JP, A) JP-A-4-213805 (JP, A) JP-A-58-176127 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 35 / 00-35/22 C04B 35/42-35/632 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. Al₂O₃25-38% by weight, Si
O₂45-58% by weight, MgO content 12-20% by weight
% Of alumina sol, silica sol and water-soluble
Cordierite composition sol by mixing with magnesium salt
Cordierite composition sol adjustment step of adjusting theThe sol obtained in the cordierite composition sol adjustment step
To B ₂ O ₃ In terms of conversion, boric acid was added to cordierite in an amount of 0.
A gelling step of adding 0.05 to 10% by weight and gelling; 850-950 ° C.
Calcining process of calcining at different temperatures Characterized by having
For producing cordierite powder. 2. An Al ₂ O ₃ content of 25 to 38% by weight, Si
O ₂ minutes 45-58 wt%, MgO content from 12 to 20 weight
% Of alumina sol, silica sol and water-soluble
Cordierite set made by mixing with magnesium salt
Boric acid is added to the synthesized sol in an amount of 0.05 to 10 weight in terms of B ₂ O _3.
% Added slurry at a temperature of 800 to 1200 ° C.
A method for producing cordierite powder, which is performed by mist roasting . (3)Al ₂ O ₃ 25-38% by weight, Si
O ₂ 45-58 wt%, MgO content 12-20 wt%
% Of alumina sol, silica sol and water-soluble
Cordierite composition sol by mixing with magnesium salt
Cordierite composition sol adjustment step of adjusting the The sol obtained in the cordierite composition sol adjustment step
To B ₂ O ₃ In terms of conversion, boric acid was added to cordierite in an amount of 0.
A gelling step of adding 0.05 to 10% by weight and gelling; A calcining step of calcining the gelled product obtained in the gelling step
When, After pulverizing and molding the calcined product obtained in the calcining step,
A sintering step of sintering at a temperature of 0 to 1050 ° C.
 Cordierite characterized by the following:porcelainManufacturing method. (4)Al ₂ O ₃ 25-38% by weight, Si
O ₂ Minutes 45-58 Weight%, MgO content is 12 ~ 20 weight
% Of alumina sol, silica sol and water-soluble
Cordierite set made by mixing with magnesium salt
Boric acid is B in synthetic sol ₂ O ₃ 0.05-10 weight in conversion
Spray roasting the slurry with the% added, The powder obtained in the above step is molded, and 950 to 1050 ° C
A sintering step of sintering at a temperature of Characterized by
CordieriteporcelainManufacturing method.