JP2002321970A - Method of manufacturing ceramic sintered compact and method of manufacturing laminated ceramic electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a ceramic sintered compact which can be manufactured at a low temperature and which is sufficiently densified and crystallized. SOLUTION: When a raw material mainly composed of a ceramic composition in which a hard-to-sinter high temperature phase can be formed from a easy-to- sinter low temperature phase is calcined, the following processes are carried out: a primary heat treatment process for obtaining an intermediate sintered- compact sintered and densified by heat treatment at a first temperature which is higher than the sintering temperature of the low temperature phase and at which the high temperature phase is not formed substantially; a secondary heat treatment process for obtaining a ceramic sintered compact, or the object, by forming the high temperature phase by heat-treating the intermediate sintered-compact at a second temperature higher than the first one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a ceramic sintered body and a method for manufacturing a multilayer ceramic electronic component, and more particularly to an improvement in a firing profile in a firing step.

[0002]

2. Description of the Related Art A multilayer ceramic electronic component such as a multilayer ceramic substrate used for forming various module substrates, various package components, composite devices, and the like, is composed of a plurality of laminated ceramic layers. It has a tie laminate. Various types of wiring conductors are provided in such a multilayer ceramic electronic component. As the wiring conductor, for example, inside the sintered laminate, an internal conductor film extending along a specific interface between ceramic layers is formed, or a via hole conductor extending to penetrate a specific ceramic layer is formed, Also,
An outer conductor film extending on the outer surface of the sintered laminate is formed.

It is desirable that the above-mentioned wiring conductor has a low electric resistance. Therefore, a metal having a high electric conductivity such as copper or silver is used as a conductive material for the wiring conductor.

[0004] In order to obtain a sintered laminate, a step of firing the green laminate is required. However, since the wiring conductor is already formed in the raw laminate, the wiring conductor is also subjected to the firing step. Will be attached. Therefore, the temperature applied in the firing step must be lower than the melting point of the metal included as a conductive material in the wiring conductor.

Under such circumstances, the above-mentioned copper or silver has a relatively low melting point, so that a so-called low-temperature sintered ceramic material which can be sintered at a relatively low temperature is used as a ceramic material constituting the ceramic layer. Used.

Conventionally, as a low-temperature sintered ceramic material,
A mixed composition of an inorganic aggregate such as alumina and a low-melting glass, that is, a so-called glass ceramic is mainly used. In glass ceramic, about half of the volume is occupied by a glass phase having an indeterminate structure.

For this reason, glass ceramics are often inferior to polycrystalline materials in terms of dielectric loss and thermal conductivity. In addition, low-melting glass generally contains a large amount of alkali metal and boron, which may cause a decrease in reliability under conditions such as a plating step and high temperature and high humidity. Furthermore, the cost of manufacturing glass is high, which increases the material cost of the entire glass ceramic.

In order to solve these problems of glass ceramics, Japanese Patent Application Laid-Open No. 8-175864 discloses that low-temperature sintering is realized by using a kaolinite group clay or a mixture of kaolin and CaO as a ceramic raw material. It is described. In the technique described here, kaolin and CaO interdiffuse at a high temperature to become a Si-Al-Ca-based amorphous material, and soften and flow to sinter.
Anorthite and gehlenite are deposited. In particular, anorthite has excellent electrical characteristics and a thermal expansion coefficient close to that of Si, and thus is suitable for uses such as a substrate and a package.

[0009]

SUMMARY OF THE INVENTION The above-mentioned JP-A-8-1
No. 75864, the Si-Al-Ca amorphous and the so-called crystallized glass are completely different thermodynamically.

[0010] Crystallized glass is in a liquid supercooled state, and the lower the temperature, the more thermodynamically the crystal is stable. On the other hand, the Si-Al-Ca-based amorphous is a precursor for crystal precipitation, and the higher the temperature, the more stable the crystal.

Further, when the amorphous becomes crystalline, the sinterability is greatly reduced.

Therefore, if the temperature is set too high in the firing process, the amorphous will crystallize before sintering,
A dense sintered body cannot be obtained. Conversely, when the temperature is too low, sintering occurs, but crystallization hardly occurs substantially, so that a sintered body with much crystallinity cannot be obtained. Therefore, if firing is performed while controlling the temperature range so that the crystallization rate is not too high and not too low, it is possible to obtain a crystalline dense sintered body.

However, the above-mentioned method has a serious practical problem as follows.

1. The rate of progress of crystallization is not constant in reality, and is sensitive to slight variations in the composition, particle size or history of the raw materials, or firing conditions. Therefore, when a firing step of performing crystallization at the same time as sintering is employed, the sintering rate is greatly affected by the crystallization rate. As a result, variations in the density and the crystal volume ratio after firing for each manufacturing lot tend to increase, which is not suitable for applications requiring extremely narrow tolerances in characteristics of electronic components and the like.

2. To reduce the dielectric loss, it is necessary to increase the crystallinity, and to increase the crystallinity,
Heat treatment at a high temperature is most effective.
According to the method described in Japanese Patent No. 864, the firing temperature cannot be sufficiently higher than the crystallization temperature.

3. In the method described in Japanese Patent Application Laid-Open No. 8-175864, the only crystalline phase that can be used is the crystalline phase that precipitates first when the amorphous material is gradually heated, and the crystalline phase that precipitates at a higher temperature cannot be used.

It is an object of the present invention to provide a method for manufacturing a ceramic sintered body and a method for manufacturing a multilayer ceramic electronic component based on the method, which can solve the above-mentioned problems.

[0018]

SUMMARY OF THE INVENTION A method for producing a ceramic sintered body according to the present invention is capable of producing a hardly sinterable high temperature phase from an easily sinterable low temperature phase. Preparing a raw material mainly composed of a ceramic composition containing a low-temperature phase of a substance that does not substantially generate a high-temperature phase at or below a sintering temperature of a powder compact having a particle size of 1.0 μm or less; A first heat treatment step for obtaining a sintered and densified intermediate sintered body by subjecting the raw material to a heat treatment at a first temperature not lower than the sintering temperature and substantially not producing a high-temperature phase; The second is higher than the first temperature
Heat treatment at a temperature of
Thereby, a secondary heat treatment step for obtaining a target ceramic sintered body is provided.

As described above, the reason why "the center particle size is 1.0 μm or less" is for specifying the sintering temperature. That is, if the center particle size changes, the sintering temperature also changes, so that the sintering temperature cannot be specified without defining the center particle size.

In order to more reliably achieve sintering for obtaining a ceramic sintered body, it is preferable that the above-mentioned ceramic composition contains at least 20% by weight of a low-temperature phase.

As described above, according to the present invention, in the firing profile, two-stage heat treatment of the first heat treatment and the second heat treatment is performed, and in the first heat treatment step, sintering proceeds, but crystallization proceeds. Performs a heat treatment in a temperature range that does not substantially occur, that is, in a densification region, whereby the densification can proceed sufficiently. A heat treatment in the activation zone is performed, whereby crystals can be sufficiently precipitated.

In the present invention, the first heat treatment step is preferably performed until the water absorption of the intermediate sintered body becomes 5% or less.

Preferably, in the first heat treatment step,
Heat treatment is performed for 10 minutes or more in a temperature range of 800 to 930 ° C., and in the second heat treatment step, heat treatment is performed at a temperature of 1050 ° C. or less.

[0024] Preferably, in the first heat treatment step,
800 to 93 until the water absorption of the intermediate sintered body becomes 5% or less.
The heat treatment is performed in a temperature range of 0 ° C., and in the second heat treatment step, the heat treatment is performed at a temperature of 1050 ° C. or less.

In the present invention, the ceramic composition to which the above-described heat treatment is applied includes, for example,
(1) 62 to 82 parts by weight in terms of oxide weight after burning,
Kaolinite group layered aluminosilicate or 10
An AlSi-based layered oxide powder obtained by heat treatment at a temperature of not more than 00 ° C .;
~ 38 parts by weight of CaO, Ca (OH) ₂ and CaC
A mixture obtained by mixing fine powder of a Ca compound selected from O ₃ and calcining the mixture at a temperature of 800 to 950 ° C. is used.

The above-described ceramic composition may contain borosilicate glass. In this case, 100 parts by weight of the above-mentioned mixture,
~ 30 parts by weight of borosilicate glass are mixed, and
Those obtained by calcining at a temperature of 00 to 950 ° C are used.

Other ceramic compositions include, for example, (1) a layered aluminosilicate of a kaolinite group or an AlSi-based layered oxide powder obtained by heat-treating the same at a temperature of 1000 ° C. or less; 2) MgO, Mg
A fine powder of a Mg compound selected from (OH) ₂ and MgCO ₃ is mixed at a ratio of 0.8 to 1.0 mol of MgO with respect to 1 mol of Al ₂ O ₃ , and this mixture is mixed with 800 What was obtained by calcining at a temperature of ９950 ° C. can be used.

The above-described ceramic composition may contain a boron compound. In this case, as a ceramic composition, 100 parts by weight of the above-mentioned mixture and further 0.1 parts by weight.
A mixture obtained by mixing 1 to 3.5 parts by weight of a boron compound and calcining the mixture at a temperature of 800 to 950 ° C. can be used.

The present invention is also directed to a method for manufacturing a multilayer ceramic electronic component.

This method of manufacturing a laminated ceramic electronic component is capable of generating a hardly sinterable high-temperature phase from an easily sinterable low-temperature phase. A step of preparing a ceramic slurry comprising a ceramic composition including a low-temperature phase of a substance that does not substantially generate a high-temperature phase below a sintering temperature of a powder compact, and a plurality of steps formed by using the ceramic slurry. A step of producing a green laminate, comprising a laminated ceramic green layer, and a wiring conductor provided in relation to a specific one of the ceramic green layers, and forming the green laminate at a temperature equal to or higher than the sintering temperature. The first in which a high-temperature phase is not substantially formed
A first heat treatment step for obtaining a sintered and densified intermediate sintered body, and a heat treatment of the intermediate sintered body at a second temperature higher than the first temperature. A secondary heat treatment step for generating a high-temperature phase and thereby obtaining a sintered laminate for the intended multilayer ceramic electronic component.

[0031]

FIG. 1 is a cross-sectional view schematically showing a multilayer ceramic substrate 1 as an example of a multilayer ceramic electronic component having a ceramic sintered body manufactured by a manufacturing method according to an embodiment of the present invention. It is.

The multilayer ceramic substrate 1 has a sintered laminate 3 composed of a plurality of laminated ceramic layers 2. In this sintered laminate 3, the ceramic layer 2
Various wiring conductors are provided in connection with the specific one of the above.

As the above-mentioned wiring conductor, the sintered laminate 3
The outer conductor films 4 and 5 formed on the end faces in the stacking direction of the ceramic layers 2, the inner conductor films 6 formed along a specific interface between the ceramic layers 2, and the specific layers of the ceramic layer 2 There are several via-hole conductors 7 formed so as to penetrate through.

The above-described external conductor film 4 is used for connection to electronic components 8 and 9 to be mounted on the outer surface of the sintered laminate 3. In FIG. 1, for example, an electronic component 8 having a bump electrode 10 like a semiconductor device and a planar terminal electrode 1 like a chip capacitor are shown.
An electronic component 9 comprising 1 is shown.

The external conductor film 5 is used for connection to a mother board (not shown) on which the multilayer ceramic substrate 1 is mounted.

The sintered laminate 3 provided on the multilayer ceramic substrate 1 includes a plurality of laminated ceramic green layers to be the ceramic layers 2, wiring conductors such as the internal conductor film 6 and the via-hole conductor 7, and In some cases,
This is obtained by firing a green laminate including the wiring conductors such as the external conductor films 4 and 5.

The above-mentioned ceramic green layer is capable of forming a hardly sinterable high-temperature phase from an easily sinterable low-temperature phase, and is a powder compact having a low-temperature phase having a center particle size of 1.0 μm or less. A ceramic slurry containing a ceramic composition containing a low-temperature phase of a substance that does not substantially form a high-temperature phase below the sintering temperature of. Typically,
The laminated structure of the ceramic green layer is provided by stacking ceramic green sheets obtained by molding a ceramic slurry. Here, preferably,
It is intended to contain at least 20% by weight of the low-temperature phase.

The ceramic composition contained in the ceramic slurry includes, for example, (1) 62 to 82 parts by weight of a kaolinite group layered aluminosilicate or a temperature of 1000 ° C. or less, in terms of oxide weight after burning. And (2) 18 to 38 parts by weight of CaO, in terms of oxide weight after burning,
Ca (OH) was mixed with fine powder of ₂ and CaCO ₃ Ca compounds selected from the mixture 800 to 950
The one obtained by calcining at a temperature of ° C. is used.

The above-described ceramic composition may include borosilicate glass. In this case, 100 parts by weight of the above-mentioned mixture,
~ 30 parts by weight of borosilicate glass are mixed, and
Those obtained by calcining at a temperature of 00 to 950 ° C are used.

Alternatively, contained in the ceramic slurry
As the ceramic composition, for example, (1) Kaolina
Layered aluminosilicate of the group
Of AlSi-based layered oxide obtained by heat treatment at the following temperature
Powder and (2) MgO, Mg (OH)_TwoAnd MgCO
_ThreeA fine powder of a Mg compound selected from_TwoO _Three
The ratio of MgO to 0.8 to 1.0 mole per mole of
The mixture is temporarily mixed at a temperature of 800 to 950 ° C.
What is obtained by baking is used.

The above-mentioned ceramic composition may contain a boron compound such as boric acid or borosilicate glass. In this case, the ceramic composition includes the mixture 10 described above.
A mixture obtained by further mixing 0.1 to 3.5 parts by weight of a boron compound with 0 parts by weight and calcining the mixture at a temperature of 800 to 950 ° C. is used.

In the firing step for obtaining the sintered laminate 3 from the green laminate obtained as described above, a primary heat treatment step in the temperature range of the densification region and a sintering process in the temperature range of the crystallization region are performed. 2
A two-stage heat treatment including a next heat treatment process is performed.

The first heat treatment step is for heat-treating the green laminate to obtain a sintered and densified intermediate sintered body. In this case, as described above, the central grain size of the low-temperature phase is used. Is applied at a temperature not lower than the sintering temperature of the powder compact having a particle size of 0.1 μm or less and a high temperature phase is not substantially generated.

In the second heat treatment step, the intermediate sintered body is heat-treated at a second temperature higher than the first temperature to generate a high-temperature phase. To gain.

In the above-mentioned first heat treatment step, in order to sufficiently achieve the densification of the intermediate sintered body, it is preferable to perform heat treatment until the water absorption of the intermediate sintered body becomes 5% or less. , 800-930 ° C. for 10 minutes or more.

On the other hand, in the second heat treatment step, heat treatment is performed at a second temperature higher than the first temperature applied in the first heat treatment step in order to sufficiently precipitate crystals of a high-temperature phase. Preferably, a temperature of 1050 ° C. or lower is applied.

The outer conductor films 4 and 5 are formed on the outer surface of the sintered laminate 3 obtained as described above, if necessary, are subjected to rust prevention treatment, and the electronic components 8 and 9 are mounted. Then, the multilayer ceramic substrate 1 as shown in FIG. 1 is completed.

Next, the present invention will be described based on more specific embodiments.

(Example 1) As a ceramic raw material, a kaolinite clay produced in the United States fired at 900 ° C (hereinafter, “baked kaolin”) was used. This calcined kaolin is
Its central particle size was 1.2 μm, and according to the analysis by XRD, no large diffraction peak was recognized except for some Al ₂ SiO ₅ crystals. From this, it is considered that most of the calcined kaolin has an amorphous structure.

To 68.6 parts by weight of the calcined kaolin, 31.4 parts by weight of a CaCO ₃ powder having a center particle diameter of 1.0 μm was added, and mixed for 24 hours by a wet method. The composition of this mixture, expressed in terms of the mole fraction of oxides, is 49.5% SiO _2.
%, Al ₂ O ₃ is estimated to be 25.0%, and CaO is estimated to be 25.5%. According to the XRD analysis of this mixture, as shown in FIG. 2, no large peak was observed other than the peak of CaCO ₃ , and the calcined kaolin was found to have undergone structural destruction during wet pulverization and became amorphous. Guessed.

Next, the above mixture was calcined at 830 ° C. for 4 hours. By this calcination, CaCO ₃ is thermally decomposed and CaO 3
At the same time, mutual diffusion between calcined kaolin and CaO proceeds. According to the XRD analysis of the calcined product, almost no sharp diffraction peak was observed as shown in FIG.
It is presumed that the whole became amorphous. This calcined material can be sintered at a low temperature similarly to glass powder, and at the same time, has properties as a precursor for crystallization.

Next, a ceramic slurry was prepared by mixing the calcined product with generally available additives such as an organic binder, an organic solvent and a dispersant. A ceramic green sheet was formed by applying a doctor blade method to the ceramic slurry. Then, a green laminate was obtained by laminating and pressing the ceramic green sheets.

Next, the green laminate was fired in an electric furnace. More specifically, the binder removal is almost completed at a temperature of 800 ° C. or less while adjusting the heating rate and the atmosphere.
The temperature was raised to a temperature of 900 ° C. at a rate of temperature rise of 900 ° C./min, and the temperature was maintained for 60 minutes to substantially complete the densification of the sintered body. Further, the temperature was raised to a temperature of 970 ° C. 30
Crystallization was carried out by holding for minutes.

The XR of the sintered laminate thus obtained was
According to D analysis, anorthite was formed as the main phase.

(Comparative Examples 1 to 3) As in the case of Example 1, the green laminate obtained in Example 1 was debindered at a temperature of 800 ° C. or less. The temperature was raised to a temperature of 950 ° C. in Comparative Example 2 and 980 ° C. in Comparative Example 3, respectively, at a temperature rising rate of 5 ° C./min. A bonded laminate was obtained.

(Comparison between Example 1 and Comparative Examples 1 to 3) In Comparative Example 1, the sintering was performed at a temperature of 920 ° C.
%, But the anorthite crystal precipitation was insufficient, leaving a considerable amount of amorphous phase. For this reason, the dielectric loss is large, and it is not suitable as an electronic component.

Next, in Comparative Example 2, although it was fired at a temperature of 950 ° C., it was sufficiently densified and crystals were precipitated, but the firing temperature was low, so that the crystallinity was low and the dielectric loss was somewhat low. It was big.

Next, in Comparative Example 3, since sintering was performed at a temperature of 980 ° C., crystallization proceeded before sintering was completed.
As a result, a very porous sintered body was obtained.

On the other hand, in Example 1, since the sintering and densification was almost completed, the temperature was raised to a sufficiently high temperature to precipitate crystals, so that the mechanical and electrical characteristics were increased. In each case, excellent sintered bodies were obtained. In Example 1, since the progress of sintering does not depend on the rate of crystallization, the tolerance of density and shrinkage after sintering becomes small,
A sintered body suitable for applications requiring high precision, such as electronic components, was obtained.

The Q value and bending strength of each of Example 1 and Comparative Examples 1 to 3 were evaluated. The Q value was measured at 1 MHz, and the average value for 5 samples was obtained. The bending strength was 20 mm × 8.8.
Using a test piece of mm × 1.0 mm, a three-point bending test was performed, and an average value for 10 samples was obtained. These results are shown in Table 1.

[0061]

[Table 1]

From Table 1, it can be seen that the sintered body according to Example 1 is superior in both mechanical properties and electrical properties as compared with the sintered bodies according to Comparative Examples 1 to 3. Understand.

Example 2 59.7 parts by weight of the calcined kaolin used in Example 1 was mixed with CaC having a central particle size of 1.0 μm.
40.3 parts by weight of O ₃ powder was added and mixed for 24 hours by a wet method. The composition of this mixture, expressed in terms of mole fraction of oxide,
SiO ₂ is 44.1% Al ₂ O ₃ 22.2% and CaO is estimated 33.7%.

Next, the above mixture is calcined at a temperature of 800 ° C. for 4 hours, and the obtained calcined product is mixed with generally commercially available additives such as an organic binder, an organic solvent and a dispersant. Then, a ceramic slurry was prepared, and a ceramic green sheet was formed by applying a doctor blade method to the ceramic slurry, and the ceramic green sheets were laminated and pressed to obtain a raw laminate.

Next, the green laminate was fired in an electric furnace. More specifically, the binder removal is almost completed at a temperature of 800 ° C. or less while adjusting the heating rate and the atmosphere.
The temperature was raised to a temperature of 860 ° C. at a rate of temperature increase of 60 ° C./min, and the temperature was maintained for 60 minutes. Almost the sinter densification was completed. By doing so, crystallization was performed. According to XRD analysis of the obtained sintered body, anorthite and gehlenite were generated as main phases.

(Comparative Examples 4 to 6) The green laminate obtained in Example 2 was debindered at a temperature of 800 ° C. or less, as in Example 2, and in Comparative Example 4, 850 ° C. The temperature was raised to a temperature of 900 ° C. in Comparative Example 5 and to 950 ° C. in Comparative Example 6, respectively, at a rate of 5 ° C./min. A bonded laminate was obtained.

(Comparison between Example 2 and Comparative Examples 4 to 6) In Comparative Example 4, since it was fired at a temperature of 850 ° C., it was sufficiently sintered, but the crystal precipitation was insufficient and a considerable amount of The amorphous phase remained. For this reason, the dielectric loss is large,
It became unsuitable as an electronic component.

Next, in Comparative Example 5, although it was fired at a temperature of 900 ° C., it was sufficiently densified and crystals were precipitated. However, since the firing temperature was low, the crystallinity was low, and thus the dielectric loss was somewhat low. It was big.

Next, in Comparative Example 6, since sintering was performed at a temperature of 950 ° C., crystallization progressed before sintering was completed.
As a result, a very porous sintered body was obtained.

On the other hand, in Example 2, since the sintering and densification was almost completed, the temperature was raised to a sufficiently high temperature to precipitate the crystals, so that the same as in Example 1 was used. Thus, a sintered body having excellent mechanical properties and electrical properties was obtained. In addition, according to the second embodiment, as in the first embodiment, the progress of sintering does not depend on the crystallization speed, so that the tolerance of density and shrinkage after sintering is reduced,
A sintered body suitable for applications requiring high precision, such as electronic components, was obtained.

Table 2 shows the Q value and flexural strength of Example 2 and Comparative Examples 4 to 6 evaluated by the same method as in Example 1 described above.

[0072]

[Table 2]

From Table 2, it can be seen that the sintered body according to Example 2 can obtain excellent mechanical and electrical characteristics as compared with the sintered bodies according to Comparative Examples 4 to 6. Understand.

(Example 3) Baking used in Example 1
With respect to 84.2 parts by weight of kaolin, the center particle diameter is 0.6 μm.
14.6 parts by weight of MgO powder and B_TwoO_ThreePowder 1.
Each 2 parts by weight was added and mixed for 24 hours by a wet method. this
The composition of the mixture, expressed in terms of mole fraction of oxide, is SiO 2_Two
Is 49.9%, Al_TwoO_Three25.1%, MgO 2
4.8%, B _TwoO_ThreeIs estimated to be 0.2%.

Next, the above mixture was heated at a temperature of 850 ° C. for 12 hours.
A ceramic slurry is prepared by mixing the calcined product obtained by calcining for hours with additives such as an organic binder, an organic solvent and a dispersant which are commercially available, and a doctor blade method is applied to the ceramic slurry. By applying, a ceramic green sheet was formed, and these ceramic green sheets were laminated and pressed to obtain a green laminate.

Next, the green laminate was fired in an electric furnace. More specifically, the binder removal is almost completed at a temperature of 800 ° C. or less while adjusting the heating rate and the atmosphere.
The temperature was raised to a temperature of 930 ° C. at a rate of temperature increase of 30 ° C./min, and maintained at this temperature for 60 minutes, thereby almost completing the sintering densification. By doing so, crystallization was performed. According to the XRD analysis of the obtained sintered laminate, cordierite was generated as a main phase.

(Comparative Examples 7 to 9) As in Example 3, the green laminate obtained in Example 3 was debindered at a temperature of 800 ° C. or less. The temperature was raised at a rate of 5 ° C./min to 980 ° C. in Comparative Example 8, and to 1030 ° C. in Comparative Example 9 for 60 minutes. A bonded laminate was obtained.

(Comparison between Example 3 and Comparative Examples 7 to 9) In Comparative Example 7, since it was fired at a temperature of 930 ° C., it was sufficiently sintered, but the crystal precipitation was insufficient and a considerable amount of The amorphous phase remained. Therefore, the dielectric loss is large,
It became unsuitable as an electronic component.

Next, in Comparative Example 8, although it was fired at a temperature of 980 ° C., it was sufficiently densified and crystals were precipitated, but the crystallinity was low due to the low firing temperature, so that the dielectric loss was slightly high. It was big.

Next, in Comparative Example 9, since sintering was performed at a temperature of 1030 ° C., crystallization proceeded before sintering was completed, and as a result, a very porous sintered body was obtained.

On the other hand, in Example 3, after the sinter densification was almost completed, the temperature was raised to a sufficiently high temperature.
Since crystals were precipitated, a sintered body excellent in both mechanical properties and electrical properties was obtained as in Examples 1 and 2. Further, according to Example 3, similarly to Examples 1 and 2, the progress of sintering does not depend on the crystallization speed, so that the tolerance of the density and shrinkage after sintering is reduced, and electronic components and the like are reduced. A sintered body suitable for applications requiring high precision was obtained.

Table 3 shows the results of evaluating the Q value and bending strength of Example 3 and Comparative Examples 7 to 9 in the same manner as in Example 1 and the like.

[0083]

[Table 3]

From Table 3, it can be seen that the sintered body according to Example 3 can obtain excellent mechanical and electrical characteristics as compared with the sintered bodies according to Comparative Examples 7 to 9. Understand.

[0085]

As described above, according to the present invention, it is possible to generate a hardly sinterable high-temperature phase from an easily sinterable low-temperature phase, and the low-temperature phase has a center particle diameter of 1.0 μm. When firing a raw material mainly composed of a ceramic composition containing a low-temperature phase of a substance that does not substantially generate a high-temperature phase at or below the sintering temperature of the powder compact, the raw material is heated at the sintering temperature or higher. A first heat treatment step for obtaining a sintered and densified intermediate sintered body by performing a heat treatment at a first temperature at which a high-temperature phase is not substantially generated; and a step of heating the intermediate sintered body to a temperature higher than the first temperature. By performing the heat treatment at the second temperature, a high-temperature phase is generated, and thereby, a two-stage sintering step including a secondary heat treatment step for obtaining a target ceramic sintered body is performed.

Accordingly, in the first heat treatment step, sintering proceeds, but crystallization does not substantially occur, so that densification can be sufficiently advanced. In the second heat treatment step, crystals are sufficiently precipitated. be able to.

Therefore, the mechanical and electrical properties of the obtained ceramic sintered body can be improved. Further, according to the present invention, since the progress of sintering does not depend on the crystallization speed, the tolerance of the density and shrinkage after sintering is reduced, such as a multilayer ceramic electronic component requiring high precision. A ceramic sintered body suitable for use in electronic components can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a multilayer ceramic substrate 1 as an example of a multilayer ceramic electronic component obtained by applying a manufacturing method according to an embodiment of the present invention.

FIG. 2 is a view showing an XRD pattern of a mixture in Example 1.

FIG. 3 is a view showing an XRD pattern of a calcined product in Example 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multilayer ceramic substrate 2 Ceramic layer 3 Sintered laminated body 4, 5 Outer conductor film 6 Inner conductor film 7 Via-hole conductor

Claims (9)

[Claims] 1. A sintering temperature of a powder compact having a low-temperature phase having a center particle size of 1.0 μm or less, which is capable of generating a low-sinterability high-temperature phase from an easily-sinterable low-temperature phase. In the following, a step of preparing a raw material mainly composed of a ceramic composition including a low-temperature phase of a substance in which the generation of a high-temperature phase does not substantially occur, and the high-temperature phase is substantially higher than the sintering temperature of the raw material. By performing the heat treatment at the first temperature that does not generate,
A first heat treatment step for obtaining a sintered and densified intermediate sintered body; and a heat treatment of the intermediate sintered body at a second temperature higher than the first temperature to generate a high-temperature phase, And a secondary heat treatment step for obtaining a target ceramic sintered body. 2. The method for producing a ceramic sintered body according to claim 1, wherein the first heat treatment step is performed until the water absorption of the intermediate sintered body becomes 5% or less. 3. The method according to claim 1, wherein in the first heat treatment step, 800 to 93
The method for producing a ceramic sintered body according to claim 1, wherein heat treatment is performed for 10 minutes or more in a temperature range of 0 ° C., and in the second heat treatment step, heat treatment is performed at a temperature of 1050 ° C. or less. 4. In the first heat treatment step, heat treatment is performed in a temperature range of 800 to 930 ° C. until the water absorption of the intermediate sintered body becomes 5% or less, and in the second heat treatment step, 1050 ° C. The method for producing a ceramic sintered body according to claim 1, wherein the heat treatment is performed at the following temperature. 5. The ceramic composition comprises: (1) 62 to 82 parts by weight in terms of oxide weight after burning,
Kaolinite layered aluminosilicate or 10
AlSi-based layer obtained by heat treatment at a temperature below 00 ° C
(2) 18 to 38 parts by weight in terms of oxide weight after burning,
CaO, Ca (OH) _TwoAnd CaCO_ThreeChosen from
It is obtained by mixing with a fine powder of Ca compound and calcining this mixture at a temperature of 800 to 950 ° C.
The cell according to any one of claims 1 to 4, wherein
A method for producing a lamic sintered body. 6. The ceramic composition according to claim 1, wherein
The ceramic sintered body according to claim 5, which is obtained by further mixing 1 to 30 parts by weight of borosilicate glass with 00 parts by weight and calcining the mixture at a temperature of 800 to 950 ° C. How to make the body. 7. The ceramic composition comprises: (1) a layered kaolinite aluminosilicate or AlSi obtained by heat-treating the same at a temperature of 1000 ° C. or lower.
System powder layered oxide, (2) MgO, and fine powder of Mg (OH) ₂ and MgCO ₃ Mg compound selected from, MgO is relative to 1 mole of Al ₂ O ₃ 0.8 to 1 The method for producing a ceramic sintered body according to any one of claims 1 to 4, wherein the mixture is obtained by mixing at a ratio of 0.0 mol and calcining the mixture at a temperature of 800 to 950 ° C. 8. The mixture of claim 1, wherein the ceramic composition comprises
The method according to claim 7, wherein the mixture is obtained by further mixing 0.1 to 3.5 parts by weight of a boron compound with 00 parts by weight and calcining the mixture at a temperature of 800 to 950 ° C. Manufacturing method of ceramic sintered body. 9. A sintering temperature of a powder compact having a low-temperature phase having a center particle diameter of 1.0 μm or less, wherein a high-temperature phase having low sinterability can be generated from a low-temperature phase having easy sinterability. In the following, a step of preparing a ceramic slurry comprising a ceramic composition comprising a low temperature phase of a substance in which the formation of a high temperature phase substantially does not occur, and a plurality of laminated ceramic green layers formed with the ceramic slurry, and Producing a green laminate, comprising a wiring conductor provided in association with a particular one of the ceramic green layers; A first heat treatment step for obtaining a sintered and densified intermediate sintered body by performing a heat treatment at a first temperature which is not performed, and a heat treatment of the intermediate sintered body at a second temperature higher than the first temperature. By Rukoto, to produce a high-temperature phase, thereby and a second heat treatment step to obtain a sintered laminate for multilayer ceramic electronic components of interest, the method of fabricating the multilayer ceramic electronic component.