JPH0617250B2 - Glass ceramic sintered body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an insulating material such as a multilayer wiring board for mounting a large number of highly integrated LSIs that can be co-fired with a low resistance metal such as silver, silver-palladium, or gold. The present invention relates to a glass ceramic sintered body used for manufacturing.

[Background technology]

In recent years, in a multilayer wiring board on which a large number of highly integrated LSIs and various elements are mounted, the use of a multilayer wiring board made of a ceramic material has been expanding as the demand for miniaturization and high reliability has increased.

In the ceramic multilayer wiring board, a green sheet is formed using alumina as a main material, and a conductor wiring of a refractory metal (Mo, W, etc.) is printed and formed on the green sheet by a thick film technique. After that, a multilayer green sheet obtained by laminating and stacking the green sheets is fired in a high temperature non-oxidizing atmosphere of about 1500 to 1600 ° C.

However, in the above-mentioned multi-layered wiring board containing alumina as a main material, the high relative permittivity of alumina and the high resistance of the fine wiring conductors (high melting point metals such as Mo and W) cause the multi-layered wiring to have The transmission time of the propagating signal was long, and it was difficult to meet the demand for higher speed.

In order to solve this problem, a low resistance metal material (Au, Ag, Ag-Pd,
It is also conceivable to form fine wiring by using Cu or the like). However, each of the low resistance metal materials mentioned above has a melting point of 1
It is around 000 ° C., which is much lower than the sintering temperature of alumina. Therefore, even if it is used, there is a problem that the wiring pattern melts before the sintering and contracts due to the surface tension, resulting in disconnection.

In order to solve this problem, a multilayer wiring board of glass or a glass powder sintered body (glass-ceramic body) has been proposed.

Such a glass powder sintered body, especially SiO ₂ -Al
Specific examples of ₂ O ₃ -MgO type (hereinafter referred to as “cordierite type”) are disclosed in JP-B-59-22399, JP-A-59-178752, and JP-B-57-6257.
And Japanese Patent Publication No. 59-46900. However, Japanese Patent Publication No. 59-22399,
JP-B-57-6257 and JP-A-59-178.
In all of the glass powder sintered bodies described in Japanese Patent No. 752 Publication, migration phenomenon occurs because the composition contains elements having relatively high ion conductivity such as Na, K, Li, and Pb. Therefore, there is a problem that deterioration of the insulating property, which is the most important characteristic of the substrate, is likely to occur. On the other hand, the glass powder sintered body described in Japanese Examined Patent Publication No. 59-46900 does not contain the above-mentioned elements having high ionic conductivity, and there is no deterioration of insulation due to the migration. Moreover, the glass powder sintered body described in JP-B-59-46900 is 9
A dense sintered body can be obtained at a firing temperature near 50 ° C. However, in practice, unless the firing is performed at a temperature considerably higher than 1000 ° C., the precipitated crystals do not become complete α-cordierite, and the amount of μ-cordierite increases, so that the electrical conductivity suitable for the purpose is increased. The characteristics and coefficient of thermal expansion cannot be obtained. In addition, there is a problem that only a crystal having poor reproducibility in which α-type and μ-type are mixed can be obtained. In the conventional glass-ceramic powder, since the firing shrinkage ratio of the conductor wiring and the molded body does not match well, low resistance metal wiring is printed and formed on the molded body (green sheet) and co-fired. In some cases, there was a defect that the substrate after firing was warped or the dimensional accuracy was deteriorated.

[Object of the Invention]

In view of such circumstances, the present invention is sufficiently densified even by firing at a low temperature of 1000 ° C. or less, has a low dielectric constant, and even when used as a multilayer wiring board material, insulation deterioration due to a migration phenomenon is caused. It is an object of the present invention to provide a glass-ceramic sintered body which is suitable not only for the occurrence of wiring, but also for wiring formation using a low resistance metal material.

[Disclosure of Invention]

In order to achieve the above-mentioned object, the inventors have conducted extensive studies to improve the performance of a sintered body by combining a new type of glass (crystallizing glass) and a filler. As a result, the present invention has been completed.

Therefore, the present invention is a glass-ceramic fired body obtained by firing a mixture of a glass composition powder and a filler, wherein the glass composition powder is SiO ₂ 48 to 63 wt%, Al ₂ O ₃ 10. 25% by weight, B ₂ O ₃ 4 to 10% by weight, MgO 10 to 25% by weight, and 3 to 20% by weight of the MgO of the mother glass is at least 1 selected from the group consisting of BaO, SrO and CaO. It is characterized in that the glass composition powder and the filler have a composition of 70 to 95% by weight and a filler of 5 to 30% by weight. The gist is a glass-ceramic sintered body.

The glass ceramic sintered body according to the present invention will be described in detail below.

The composition of the mother glass is such that SiO ₂ is 48 to 63 wt%, Al is
₂ O ₃ is 10 to 25 wt%, B ₂ O ₃ is 4 to 10 wt%, and MgO is 10 to 25 wt%. In such a mother glass, 3 to 20 wt% of MgO is BaO, S
at least 1 selected from the group consisting of rO and CaO
(Hereinafter referred to as “RO” only). By doing this, the relatively high dielectric constant (9
6% alumina has a much lower dielectric constant than about 10). Moreover, Si not substituted
Like the O ₂ —Al ₂ O ₃ —MgO—B ₂ O ₃ -based glass composition, non-porous sintering can be performed at a firing temperature of around 850 ° C., up to 950 ° C. at the most. Since the main crystal phase of the sintered body is cordierite, it has a low dielectric constant and high mechanical strength. Further, since the glass raw material can be melted at a sufficient melting temperature of 1400 ° C., it can be melted sufficiently in an ordinary clay crucible or a melting furnace, which is convenient from the viewpoint of production.

The reason why the composition ratio of the glass composition used in the present invention is limited as described above is as follows.

When the composition ratio of SiO ₂ exceeds 63% by weight, it is difficult to form a dense sintered body. If it is less than 48% by weight, the crystallization temperature of the glass powder rises, so that it cannot be sufficiently crystallized at a firing temperature of 950 ° C. or less, or densification becomes difficult.

When the composition ratio of Al ₂ O ₃ exceeds 25% by weight, the temperature at which sintering can be performed increases, and sufficient sintering cannot be performed at a firing temperature of 950 ° C. or lower. When it is less than 10% by weight, the cordierite crystals are reduced and a large amount of SiO ₂ —MgO-based crystals are deposited, so that the relative dielectric constant is increased.

If the composition ratio of MgO exceeds 25% by weight,
It is thought that magnesium silicate precipitates, but the deformation is large and it is not practical. Below 10% by weight,
Difficult to become a dense sintered body.

If B ₂ O ₃ is added to the cordierite-based glass composition, it can be fired at a lower temperature, and μ−
The phase change from cordierite to α-cordierite can also be performed at 1000 ° C or lower, but when the composition ratio of B ₂ O ₃ exceeds 10% by weight, the glass phase is large and foaming is likely to occur, and firing is possible. The temperature range is narrowed. In addition, the mechanical strength is weak and the practicability becomes poor. If it is less than 4% by weight, the crystallization of the surface layer of the glass powder will proceed too rapidly, and it will be difficult to form a dense sintered body.

When the substitution rate of RO for substitution with MgO exceeds 20% by weight, the MgO component is reduced, so that the precipitation of α-cordierite crystals is deteriorated and the electric characteristics are deteriorated. If it is less than 3% by weight, the effect is not exhibited.

The filler used in the present invention is not particularly limited, but at least selected from α-quartz, fused silica, cristobalite, cordierite, steatite, forsterite, wollastonite, anorthite, sergian, and alumina. One kind is mentioned.

The filler not only increases the mechanical strength of the sintered body, but also reduces the relative dielectric constant. The addition ratio is 5% by weight to 30% by weight, preferably 5% by weight to 20% by weight. When the addition ratio of the filler exceeds 30% by weight, it becomes difficult to sinter and it becomes impossible to sinter at 1000 ° C or lower. Also, a large amount of pores will be contained inside the sintered body bulk. When the amount of the filler is less than 5% by weight, it is difficult to recognize the effects of adding the filler, such as lowering the dielectric constant, adjusting the thermal expansion coefficient, and improving the thermal conductivity.

Among the above-mentioned fillers, if a filler such as α-quartz, fused silica, cristobalite, and cordierite is used, the coefficient of thermal expansion becomes particularly close to that of silicon, so that high density is achieved. It is useful as a multi-layered substrate, and if a group other than the above is used, the thermal conductivity is particularly improved, so that it tends to be useful as a multi-layered substrate.

If a filler that does not contain the above-mentioned elements having relatively high ionic conductivity is used as the filler, even if the sintered body is used as the material for the multilayer wiring board, there is no risk of deterioration of the insulation due to the migration phenomenon.

The powder of the above glass composition is prepared, for example, by mixing the respective components so that the composition in% by weight falls within the above range, melting the mixture, and rapidly cooling the melt so as not to precipitate crystals, to obtain transparent glass. Although it can be obtained by pulverizing, it may be obtained by other methods.

The particle size of the powder of the glass composition is not particularly limited, but the average particle size is preferably 1 to 10 μm. If the average particle size exceeds 10 μm, the surface irregularities of the glass-ceramic sintered body become severe, and when the wiring board is used, the conductor accuracy of the circuit may deteriorate. In addition, since the crystallization temperature may increase, firing at 1000 ° C. or lower does not cause sufficient crystal precipitation, resulting in a sintered body with a low crystal amount.
There is a possibility that a decrease in the dielectric constant cannot be expected. At the same time, the mechanical strength may decrease, which may impair practicality. On the other hand, if it is less than 1 μm, the crystallization rate of the glass composition may be increased, and crystallization may be completed before sufficient sintering occurs, which may make it difficult to increase the sintered density. There is.

The particle size of the filler is also not particularly limited, but it is preferably set to be approximately equal to or slightly smaller than the particle size of the glass composition.

The method of mixing the glass composition and the filler is not particularly limited, and either a wet method or a dry method may be used. When an organic substance such as a resin or a solvent is used to obtain a molded body, it is preferable to perform pre-firing to remove the organic substance and then perform firing for sintering. The organic substance is not particularly limited, and various types can be used. Further, a material other than an organic material may be used, or the molded body may be obtained without using anything.

Examples of the powder compact formed by mixing the powder of the glass composition and the filler include, but are not limited to, a green sheet or a laminate of a plurality of green sheets.

The conditions for firing the shaped body are not particularly limited, but since firing can be performed even if firing is performed at a temperature lower than the melting point (around 1000 ° C.) of the low resistance metal material described above, firing at that temperature is recommended. For example, a low resistance metal material can be printed and co-fired. Of course, it is not necessary to perform simultaneous firing.

Applications of the glass ceramic sintered body according to the present invention are not limited to wiring boards such as multilayer wiring boards.

Next, a glass ceramic sintered body according to the present invention will be described in detail based on examples.

Glass compositions G-1 to G-18 in the proportions shown in Table 1
(Of these, G-1 to G-14 are those of the embodiment, G-1
5 to G-18 are those of the comparative example),
It was placed in an alumina crucible and melted at a heating temperature of about 1400 to 1500 ° C. The molten liquid thus obtained is dropped into water to give a transparent glass composition (frit).
Got This composition was thoroughly pulverized by a wet or dry method in an alumina ball mill to obtain a glass powder having an average particle size of 1 to 10 μm.

Each glass powder thus obtained and each filler were mixed in the proportions shown in Table 2, and further, polybutyl methacrylate resin as an organic binder, dibutyl phthalate as a plasticizer, toluene as a solvent, and the like were kneaded. , Defoamed under reduced pressure. Then, a 0.2 mm-thick continuous sheet was produced on the film sheet by the doctor blade method using this kneaded material. After this was dried, it was peeled off from the film sheet and punched out so as to form a 50 mm square to produce a green sheet.

Next, a wiring pattern made of a through hole and a low resistance metal material was formed by printing on each green sheet. A plurality of green sheets having the wiring pattern and the like formed thereon were laminated and press-molded to obtain a molded body.

This laminated green sheet was first heated to 500 ° C. at a rate of 150 ° C./hour and kept as it was for 2 hours and 45 minutes to remove organic substances in the green sheet. Then, at a rate of 200 ° C./hour per hour, the temperature was raised to the predetermined firing temperature shown in Table 2, and this state was maintained for 3 hours, then the temperature was lowered to 400 ° C. at a rate of 110 ° C./hour, The mixture was naturally cooled to obtain a sintered body.

Examples 1 to 20 and Comparative Examples 1 to 8 thus obtained
The permittivity (relative permittivity) and the water absorption rate of the sintered body were measured, and the results are also shown in Table 2. The coefficient of thermal expansion and the coefficient of thermal conductivity are also shown. Measurement of relative permittivity is 1M
Performed at a frequency of Hz. The water absorption was measured according to JIS C-2141.

As shown in Table 2, in the sintered bodies of Examples 1 to 20, as compared with the sintered bodies of Comparative Examples 1 to 8, in spite of the firing temperature of 950 ° C. or less, an extremely dense sintered state. Has been achieved. The relative permittivity is also a small value that is sufficiently practical. The coefficient of thermal expansion and thermal conductivity are also good.

The sintered compacts of Comparative Examples 1 to 8 did not become a dense sintered compact unless fired at a temperature of 1100 ° C. or higher. In addition, the sintered bodies of Comparative Examples 1 to 8 are not in a dense sintered state, and their relative permittivity values are apparent values (measured values appear small), and the true value of the material itself. Not a value.
Therefore, in the comparative example, the relative permittivity, thermal expansion coefficient, and thermal conductivity are not shown.

〔The invention's effect〕

As described above, the glass-ceramic sintered body of the present invention is formed by firing a powder compact formed by mixing the powder of the glass composition having the specially selected composition and the filler powder, Moreover, the relative dielectric constant is small. Moreover, it can be achieved at sintering temperatures below 1000 ° C. Since it is dense and has a low relative dielectric constant, this sintered body is suitable for a multilayer wiring board material, and since the firing temperature is 1000 ° C. or less, firing is performed at the same time by printing a low resistance metal material. The wiring can also be formed.

Claims (3)

[Claims] 1. A glass ceramic sintered body obtained by firing a mixture of a glass composition powder and a filler, wherein the glass composition powder is SiO ₂ 48 to 63 wt%, Al ₂ O ₃ 10. 25% by weight, B ₂ O ₃ 4 to 10% by weight, MgO 10 to 25% by weight, and 3 to 20% by weight of the MgO of the mother glass is at least 1 selected from the group consisting of BaO, SrO and CaO. It is characterized in that the glass composition powder and the filler have a composition of 70 to 95% by weight and a filler of 5 to 30% by weight. Glass-ceramic sintered body. 2. A patent in which the filler is at least one selected from the group consisting of α-quartz, fused silica, cristobalite, cordierite, steatite, forsterite, wollastonite, anorthite, sergian and alumina. The glass ceramic sintered body according to claim 1. 3. The glass ceramic sintered body according to claim 1 or 2, wherein firing is performed at a temperature of 1000 ° C. or lower.