JPH1143369A - High strength ceramic sintered body and method of manufacturing the same - Google Patents

Abstract

(57) [Problem] To provide a ceramic sintered body having high strength and high dielectric constant, which can be simultaneously fired with gold, silver, and copper wiring conductors, and a method of manufacturing the same. SOLUTION: As a crystal phase, a composite oxide crystal phase composed of Al ₂ O ₃ , SiO ₂ and alkaline earth oxide, for example, anorthite and / or slausonite, and Zr
And O ₂ crystal phase mainly news, further MgAl
Contains ₂ O ₄ crystal phase and TiO ₂ crystal phase and has a crystallinity of 9
By increasing it to 5% or more, a sintered body having a dielectric constant of 8 or more and a bending strength of 35 kg / mm ² or more is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength ceramic sintering which is preferably used for an insulating substrate in a wiring board on which an integrated circuit (IC) or an electronic component is mounted and which does not cause breakage or chipping due to stress. The present invention relates to a body and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as an insulating substrate such as a ceramic wiring substrate, an insulating substrate made of an alumina sintered body and having a wiring layer made of a high melting point metal such as tungsten or molybdenum formed on the surface or inside thereof is most often used. Widespread. However, conventional high melting point metals such as tungsten and molybdenum have high conductor resistance and cannot be used particularly in the millimeter wave region of 30 GHz or more. Therefore, instead of these metals, low-resistance metals such as copper, silver, and gold are used. It is necessary to use. Since a wiring layer made of such a low-resistance metal cannot be co-fired with alumina, a so-called glass ceramic made of glass or a composite material of glass and ceramic filler has recently been used as an insulating substrate. Wiring boards are being developed.

For example, as disclosed in Japanese Patent Publication No. 4-12639, an SiO ₂ filler is added to glass to form copper, silver,
Wiring layer made of low resistance metal such as gold and 900 to 1000
A multilayer wiring board and the like which are simultaneously fired at a temperature of ° C. have been proposed.

As disclosed in JP-A-60-240135, a sheet-like molded body is prepared by adding a filler such as Al ₂ O ₃ , ZrO ₂ , and mullite to a zinc borosilicate glass, and the surface thereof has a low resistance. A glass ceramic wiring board and the like which have been coated with a paste containing a metal and fired simultaneously have been proposed. In addition, JP-A-5-298919 proposes a glass-ceramic sintered body in which mullite or cordierite is precipitated as a crystal phase.

On the other hand, in order to prevent the substrate from being broken or chipped due to the stress applied to the substrate in the process of connecting various electronic components, input / output terminals, etc. to the multilayer circuit board, a material machine is used. High target strength is also required.

[0006]

However, the conventional glass-ceramic sintered body can be multi-layered and simultaneously fired with metallized layers of gold, silver, copper, etc., but has a low relative dielectric constant of 7 or less. However, it was not suitable for miniaturization. In order to increase the strength, various ceramic sintered bodies in which a spinel crystal phase such as garnet or a ZrO ₂ crystal phase is precipitated in a glass ceramic sintered body have been proposed. At most, it is about 30 kg / mm ² , which causes a problem such as cracking or chipping of the insulating substrate when connecting electronic components, input / output terminals, and the like. In addition, conventional Al
Its use is extremely limited because it is much lower than ceramic materials such as ₂ O ₃ , which is a major factor that hinders the spread of glass ceramic sintered bodies.

Accordingly, an object of the present invention is to provide a ceramic sintered body which can be multilayered using gold, silver and copper as wiring conductors and has high strength and high dielectric constant. Another object of the present invention is to provide a method for producing a ceramic sintered body which can be produced by firing a ceramic sintered body having a high strength and a high dielectric constant at a low temperature.

[0008]

[Means for Solving the Problems] The present inventors have conducted intensive studies on the above problems, and as a result, found that Al ₂ O
₃ , a sintered body mainly composed of a composite oxide crystal phase containing SiO ₂ and an alkaline earth oxide, and further containing a ZrO ₂ crystal phase, by increasing the crystallinity of the sintered body to 95% or more. It was found that the strength of the solidified body was 35 kg / mm ² or more, which was extremely high as never before.
The present invention has been reached.

That is, the ceramic sintered body of the present invention mainly comprises, as crystal phases, a composite oxide crystal phase composed of Al ₂ O ₃ and SiO ₂ and an alkaline earth oxide, and a ZrO ₂ crystal phase. A ceramic sintered body containing the sintered body having a crystallinity of 95% or more and a transverse rupture strength of 35%.
kg / mm ² or more,
Further, as a crystal phase, a MgAl ₂ O ₄ crystal phase or Ti
It contains an O ₂ crystal phase, and the composite oxide crystal phase is anorthite and / or slausonite.

The method for producing a ceramic sintered body according to the present invention is directed to a glass powder 45 containing at least SiO ₂ , Al ₂ O ₃ , an alkaline earth metal, ZnO and B ₂ O _3.
80 wt% and 5 to 30 wt% CaO and ZrO _2, or those compounds in total, SrO and Ti
A molded body containing O ₂ or a compound thereof in a total amount of 5 to 30% by weight is fired while being maintained at a temperature of 700 to 750 ° C., and is further heated to 800 to 1000 ° C. for firing. Further, a composite oxide crystal phase composed of Al ₂ O ₃ , SiO ₂ and an alkaline earth oxide, and a ZrO ₂ crystal phase are mainly deposited.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As shown in the schematic diagram of the structure of FIG.
₂ , a composite oxide crystal phase (Sl) 1 comprising Al ₂ O ₃ and an alkaline earth element oxide is defined as a main crystal phase. As the main crystal phase, an anorthite crystal represented by a chemical formula of CaAl ₂ Si ₂ O ₈ or (Ca, Sr) Al ₂ S
Slausonite crystals represented by i ₂ O ₈ are mentioned.
This main crystal phase exists as crystal particles having an average particle size of 1 to 3 μm in the sintered body. This main crystal phase contains 5
It is contained in a proportion of 0% by weight or more.

Further, as a second crystal phase other than the main crystal phase, a ZrO ₂ crystal phase (Z) 2 is essentially contained.
This ZrO ₂ crystal phase exists mainly as tetragonal and / or cubic. This ZrO ₂ crystal phase is present in the form of fine crystal particles having an average particle diameter of 100 nm or less in the grains and the grain boundaries of the composite oxide crystal phase as the main crystal phase. As described above, the presence of ZrO ₂ crystals as fine particles in the main crystal phase serves to increase the strength of the main crystal phase, and can increase the strength of the entire ceramic sintered body. ZrO _{2 also} has a function of increasing the dielectric constant of the sintered body because of its high dielectric constant. This Z
and rO _2, in the sintered body, desirably in a proportion of 10 to 30 wt%, including at particular proportion of 10 to 20 wt%. Therefore, the content of ZrO ₂ is 10% by weight.
If the amount is less than the above, it is difficult to increase the strength, and if it exceeds 30% by weight, the sinterability tends to decrease.

The ceramic sintered body of the present invention contains the above-mentioned main crystal phase and ZrO ₂ crystal phase as indispensable crystal phases as crystal phases in the sintered body. The ceramic sintered body has a high crystallinity of 95% or more, particularly 97% or more. This degree of crystallinity is very important in increasing the strength of the sintered body. In the present invention, by setting the degree of crystallinity to 95% or more, an excellent strength with a transverse rupture strength of 35 kg / mm ² or more can be obtained. Can be demonstrated.

In order to increase the crystallinity of the ceramic sintered body of the present invention, in addition to the main crystal phase and the second crystal phase, a MgAl ₂ O ₄ (spinel type) crystal phase (SP) is used.
3. It may contain at least one or more of TiO ₂ (rutile type) crystal phases (T) 4. These are crystal phases precipitated by various components contained in the sintered body, and have an action of controlling the dielectric properties of the sintered body together with the composite oxide crystal phase as the main crystal phase. . In some cases, an Al ₂ O ₃ crystal phase is precipitated.

Further, the ceramic sintered body of the present invention may contain a small amount of the glass phase 5 in some cases. In that case, the glass phase is SiO ₂ , alkaline earth element oxide,
It is made of aluminum or the like.

The ceramic sintered body of the present invention has, for example, at least SiO ₂ , Al ₂ O ₃ ,
Crystallized glass containing MgO, ZnO and B ₂ O ₃
5-80% by weight, in particular with 50 to 70 wt%, 5-30 wt% CaO and ZrO ₂ as a filler component, or those compounds in total, in particular 10 to 25 wt%, more dielectric constant and transverse rupture Zr from the relationship between the intensity total amount of 4-29 wt% in terms of ZrO ₂ amount, Ca is added in amounts of 1-15 wt% in the total amount calculated as CaO. Furthermore 5-30 wt% in total of SrO and TiO ₂ or a compound thereof as a filler, in a proportion of particularly 10 to 20 wt%. The compact containing the mixed powder in which the above ratio is blended can be densified by firing at a temperature of 800 ° C. to 1000 ° C. in a non-oxidizing atmosphere or an oxidizing atmosphere. In addition, the crystallinity can be increased to 95% or more by holding at 700 to 750 ° C. for about 0.1 to 1 hour in a non-oxidizing atmosphere or an oxidizing atmosphere. This is presumably because crystal seeds are generated by the above-mentioned temporary holding, which facilitates crystallization.

The preferred composition of the crystallized glass is as follows: SiO ₂ : 40 to 45% by weight, Al ₂ O ₃ : 25 to
30% by weight, MgO: 8 to 12% by weight, ZnO: 6 to 9
Wt%, B ₂ O _3: is a 8-11 wt%.

The reason why the amounts of glass and filler are limited to the above-mentioned ratios in the starting raw material composition is that the amount of glass is less than 45% by weight, in other words, the total amount of filler components other than glass is 55% by weight. If more, 8
At a temperature of 00 to 1000 ° C., the porcelain cannot be sufficiently densified. Conversely, if the amount of the glass is more than 80% by weight, in other words, if the total amount of the filler components is less than 20% by weight, the dielectric constant becomes low. 8, which does not meet the purpose of the present invention.

When the content of Ca and Zr is less than 5% by weight as a filler component, the strength of the sintered body is low. On the other hand, when the content is more than 30% by weight, the sintering temperature becomes higher than 1000 ° C., and gold, silver, copper This is because it becomes impossible to perform simultaneous firing such as described above.

Further, Sr and Ti are necessary for controlling the dielectric properties, and if the above range is deviated, adverse effects such as an increase in the dielectric constant, the dielectric loss tangent, or the temperature characteristic of the dielectric constant will occur.

Further, in the present invention, in order to enhance the chemical resistance of the starting material composition, an oxide of Al (Al ₂ O ₃ ) or an oxide of Al and an oxide of Si ( SiO ₂ ) in a total amount of 0.1 to 20% by weight,
Desirably, the content is 10 to 10% by weight. In particular, S
i is preferably in the range of 0 to 15% by weight of the total amount in terms of SiO ₂ . When the amount of Al or the total amount of Al and Si is less than 0.1% by weight in terms of oxide, or the amount of Al ₂ O ₃ is less than 0.1% by weight, the effect of improving chemical resistance is small. , Si and Al are more than 20% by weight or Al ₂ O ₃ is more than 20% by weight, the densification temperature of the porcelain is 100%.
This is because the temperature becomes higher than 0 ° C., and the shrinkage curves of copper, gold, and silver as conductors are greatly deviated, and a problem that the conductors peel off occurs.

In order to produce a wiring substrate using the ceramic sintered body of the present invention as an insulating substrate, the mixed powder produced as described above is subjected to a known tape molding method, for example, a doctor blade method, a rolling method or the like. After preparing a green sheet for forming an insulating layer, a metal pattern containing a powder of Ag, Au or Cu, particularly a Cu powder is used as a metallization for a wiring layer on the surface of the sheet, and a wiring pattern is formed on the sheet surface. Screen printing is performed, and in some cases, through holes are formed in the sheet to fill the holes with the paste. After that, a plurality of sheets are laminated and pressed, baked under the above-described conditions, and further subjected to a process of increasing the crystallinity, whereby a multilayer wiring board having a wiring layer on the surface and / or inside of a high-strength insulating substrate is provided. Can be produced.

[0023]

[Example] SiO ₂ -Al ₂ O ₃ -MgO-ZnO-B
Crystalline glass A: SiO ₂ 44% by weight—Al ₂ O ₃ 29 as ₂ O ₃ -based crystalline glass
Wt% -MgO11 wt% -ZnO7 wt% -B ₂ O ₃
9% by weight crystalline glass B: SiO ₂ 45% by weight, Al ₂ O ₃ 25
Wt% -MgO10 wt% -ZnO9 wt% -B ₂ O ₃
11% by weight of two kinds of glass, ZrO ₂ and CaCO _{3 having} an average particle diameter of 1 μm or less, and SrTi having an average particle diameter of 1 μm or less.
O ₃ , Al ₂ O ₃ and SiO ₂ having an average particle diameter of 1 μm or less were mixed according to the compositions shown in Tables 1 and 2. In Tables 1 and 2, for samples Nos. 1 to 17, CaZ with an average particle size of 0.7 μm was used.
rO ₃ powder was added.

Then, an organic binder, a plasticizer, and toluene were added to the mixture, and a green sheet having a thickness of 300 μm was prepared by a doctor blade method. Then, five green sheets are laminated, and 100
Thermocompression bonding was performed by applying a pressure of kg / cm ² . After debinding the obtained laminate at 500 to 700 ° C. in a water vapor-containing / nitrogen atmosphere, after holding at 730 ° C. for 30 minutes,
Further, it was fired in dry nitrogen under the conditions shown in Tables 1 and 2.

The obtained sintered body was evaluated for relative permittivity, flexural strength, and crystallinity by X-ray diffraction by the following methods.
The relative permittivity was measured by cutting a sample having a diameter of 50 mm and a thickness of 1 mm from the sample shape at 3.0 GHz by a cavity resonator method using a network analyzer and a synthesized sweeper. The measurement was performed with a dielectric substrate of a sample interposed between cylindrical cavities filled with sapphire.
The relative dielectric constant was calculated from the resonance characteristic of the TE011 mode of the resonator.

The bending strength was a sample shape having a length of 70 mm, a thickness of 3 mm, and a width of 4 mm, and a three-point bending test was performed in accordance with JIS-C-2141. Tables 1 and 2 show the measurement results.
It was shown to.

The crystallinity was evaluated by the Rietveld method since a plurality of crystal phases were precipitated. In the Rietveld method, after the obtained sintered body was pulverized, ZnO was added as an internal standard sample, ethanol was added, and wet mixing was performed. This mixing was performed until the sintered body powder and the internal standard sample became substantially uniform. From the previously weighed weights and the quantitative results obtained by the Rietveld method, the proportion of crystalline substances present in the sintered body, that is, the degree of crystallinity, was evaluated. Table 3 shows the quantitative results of the crystal phases and the crystallinity of Samples No. 2 and No. 4.

As a comparative example, a sintered body was prepared and evaluated similarly using Al ₂ O ₃ and forsterite instead of ZrO ₂ and CaO as a filler component (samples Nos. 23 and 24).

In place of the above crystalline glass, crystalline glass C: 55.2% by weight of SiO ₂ , Al ₂ O ₃
12 wt% B ₂ O ₃ 4.4 wt%, MgO20 wt%, ZnO6.
7 wt%, Na ₂ O 1.6 wt%, ZrO ₂ 0.1 wt% Crystalline glass D: SiO ₂ 60.7 wt%, Al
₂ O ₃ : 9.3 wt% B ₂ O ₃ 5 wt%, MgO 15.4 wt%, ZnO 8.
A sintered body was prepared in the same manner using glass of 6% by weight and 1% by weight of K ₂ O, and was similarly evaluated.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

As is clear from the results in Tables 1 and 2, crystallization treatment was performed and (Ca, Sr) -Al-S
i-O (slausonite) composite oxide crystal phase, ZrO
_The sintered body of the present invention containing _two crystals and having a crystallinity of 95% or more has a dielectric constant of 8 or more and a strength of 35 kg / m2.
It showed a high value of m ² or more. On the other hand, in Samples Nos. 1, 3, 5, and 7 which were not subjected to the crystallization treatment, the crystallinity could not be increased to 95% or more, and the transverse rupture strength was 35%.
It was less than kg / mm ² .

Further, Al ₂ O ₃ , SiO ₂
Samples Nos. 20 to 25 containing no composite oxide crystal phase containing ₂ and alkaline earth oxides or no ZrO ₂ crystal phase could not achieve a strength of 35 kg / mm ² or more.

[0035]

As described in detail above, the high-strength ceramic sintered body of the present invention has a high dielectric constant and excellent strength, so that it can be miniaturized in microwave circuit elements and the like. By increasing the strength of the material, it is possible to improve the reliability of the substrate in bonding and mounting leads applied to the input / output terminals. Moreover, since it is fired at 800 to 1000 ° C.,
Wiring made of Au, Ag, Cu, or the like can be formed by simultaneous firing.

[Brief description of the drawings]

FIG. 1 is a schematic view of the structure of a high-strength ceramic sintered body of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 (Ca, Sr) -Al-Si-O (slausonite) type composite oxide crystal phase 2 ZrO ₂ crystal phase 3 Spinel type crystal phase 4 TiO ₂ (rutile type) crystal phase 5 glass phase

Claims (5)

[Claims] 1. A composite oxide crystal phase comprising Al ₂ O ₃ , SiO ₂ and an alkaline earth oxide,
A ceramic sintered body mainly containing an rO ₂ crystal phase, wherein the sintered body has a crystallinity of 95% or more and a transverse rupture strength of 35 kg / mm ² or more. High strength ceramic sintered body. 2. The high-strength ceramic sintered body according to claim 1, further comprising a MgAl ₂ O ₄ crystal phase as a crystal phase. 3. The high-strength ceramic sintered body according to claim 1, further comprising a TiO ₂ crystal phase as a crystal phase. 4. The high-strength ceramic sintered body according to claim 1, wherein the composite oxide crystal phase is anorthite and / or slausonite. 5. A total amount of 45 to 80% by weight of a glass powder containing at least SiO ₂ , Al ₂ O ₃ , alkaline earth metal, ZnO and B ₂ O ₃ , and CaO and ZrO ₂ or a compound thereof. 5 to 30 wt%, the molded body containing SrO and TiO ₂ or a compound thereof in a proportion of 5 to 30 wt% in total, was calcined by keeping at a temperature of 700 to 750 ° C., further 800 to 1,000 ° C and fired to precipitate a composite oxide crystal phase composed of Al ₂ O ₃ , SiO ₂ and alkaline earth oxides, and a ZrO ₂ crystal phase mainly, thereby sintering a high-strength ceramic. How to make the body.