JPS62252341A - Sintered glass - Google Patents

Abstract

PURPOSE:To obtain sintered glass suitable as a material for multilayer printed circuit board, by forming and calcining a glass composition composed mainly of SiO2, Al2O3 and MgO. CONSTITUTION:A powdery glass composition composed of 40-60(wt)% SiO2, 10-40% Al2O3 and 10-40% MgO (10-30% of MgO is substituted with at least one kind of SrO, BaO and CaO) and containing <=5% nucleation agent selected from TiO2, ZrO2, SnO2, P2O5, ZnO, As2O3 and MoO3 is pulverized to fine powder having an average particle diameter of 1-10mum, formed to a desired form using a proper binder and calcined at <=1,000 deg.C. The obtained sintered material has dense texture and low dielectric constant and gives a multilayer printed circuit board resistant to deterioration of insulation.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is used as an insulating material for multilayer wiring boards on which a large number of highly integrated LSIs are mounted.
The present invention relates to a glass sintered body that can be obtained by co-firing with low resistance conductive metals such as silver-palladium and gold.

[Background technology]

Conventionally, there have been the following types of substrates on which LSIs are mounted. That is, a green sheet is formed using alumina as the main material, and a high melting point metal (Mo
, W, etc.) is printed by thick film technology. Thereafter, a multilayer green sheet made by laminating these green sheets together is fired in a high-temperature non-oxidizing atmosphere at about 1500°C. This is a so-called alumina sheet multilayer substrate obtained in this way.

However, in the multilayer wiring board mainly made of alumina as described above, due to the high dielectric constant of alumina and the high resistance of the miniaturized wiring conductor (high melting point metal such as Mo, W, etc.), the transmission time of the multilayer wiring board This made it difficult to meet demands for faster speeds.

In order to solve this problem, instead of high-resistance, high-melting-point metal materials, metal materials with low specific resistance (A u , A
It is also conceivable to form finer interconnections using materials such as Cu, Ag-Pd, Cu, etc.). however,
The melting point of these low resistance metal materials is around 1000°C, which is much lower than the sintering temperature of alumina.

Therefore, even if it were used, there was a problem that the wiring pattern would melt before sintering and shrink due to surface tension, resulting in disconnection or connection with other wiring.

To solve this problem, the melting point (
There is a need for materials that can be fired at temperatures below 0° C. and that have a low dielectric constant.

To meet this requirement, multilayer wiring boards made of glass or glass powder sintered bodies (glass-ceramic bodies) have been devised.

A specific example of such a glass powder sintered body is the
It is described in Japanese Patent Application Publication No. 223.99, Japanese Unexamined Patent Publication No. 178752/1982, Japanese Patent Publication No. 6257/1987, etc.

However, since both of them contain elements with relatively high ion conductivity, such as Na, Li, and Pb, a migration phenomenon occurs. Therefore, there is a problem in that insulation, which is the most important characteristic of a wiring board, tends to deteriorate.

[Purpose of the invention]

In view of these circumstances, the present invention has been developed to provide a material that can be sufficiently densified by firing at a temperature lower than the melting point of low-resistance metals, and can be used as a multilayer wiring board material without worrying about insulation deterioration due to migration phenomena. The purpose is to provide a glass sintered body with a low dielectric constant.

[Disclosure of the invention]

In order to achieve the above object, this invention
A glass sintered body obtained by firing a molded body of powder of a glass composition containing A 120x and MgO as main components, the composition of the glass composition having a Sin of 40 to 60.
Weight %, A1. Ogo is 10 to 40% by weight, MgO is 10 to 40% by weight, and 10 to 30% of the MgO is by weight O
, BaO and CaO, and TiOz , ZrO, % S
A glass sintered body characterized in that the proportion of at least one nucleating agent selected from the group consisting of PgOs% now, PgOs% ZnO, As, O, and MoO is 5% by weight or less. This is the summary.

Below, the glass sintered body according to the present invention will be explained in detail.

Glass powder within the above composition range can be sufficiently densified at a firing temperature of 850 to 950°C, and the main crystal phase of the sintered body is cordierite, so it has a low dielectric constant.
It also has great mechanical strength. In addition, when producing glass, approximately 140
Since the raw materials can be melted at temperatures below 0°C, a normal melting furnace or clay crucible can be used, which is convenient for production.

Further, the glass composition does not contain elements with relatively high ion conductivity such as Na--Li-Pb, which may cause migration.

The reason why the composition ratio of the glass composition used in this invention is limited as described above is because if the composition ratio of SiO□ exceeds 60% by weight, the sintering temperature becomes high.
It does not become densified at temperatures below 000°C. If it is less than 40% by weight, it may not be possible to vitrify the glass sufficiently even at 1500 to 1600°C during glass melting, or even if glass is obtained, the
Crystallization does not occur below ℃.

When the composition ratio of Al2O3 exceeds 40%, the temperature at which sintering can be performed increases, and sufficient sintering cannot be performed at a firing temperature of 1000° C. or lower. When it is less than 10% by weight, the amount of cordierite crystals as the main crystalline phase decreases, resulting in a sintered body with a large amount of glass, resulting in a high dielectric constant.

When the composition ratio of MgO exceeds 40% by weight, the main crystal phase is not cordierite, but MgO-5iO□-based crystals (forsterite, enstatite) are precipitated, and the dielectric constant becomes large. At the same time, the sintering temperature also increases. If it is less than 10%, it is difficult to form a dense sintered body.

Of the MgO in the above composition ratio, 10 to 30% by weight is S
r O% B a Replaced with one or more selected from the group consisting of O and CaO. When the substitution rate is less than 10% by weight, the glass melting temperature increases to 1400°C.
Melting in the vicinity becomes difficult. Further, the effect of lowering the dielectric constant cannot be achieved. When it exceeds 30% by weight, the sintering temperature becomes high and the dielectric constant becomes high. Furthermore, since the MgO component decreases, precipitation of α-cordierite crystals becomes worse, resulting in poor electrical properties.

The nucleating agent is used at a composition ratio of 5% by weight or less in order to more reliably form the crystals of the sintered body into α-cordierite. As a nucleating agent, TtO, , Z ro, , SnO
, P, Os, ZnO, MoO, As2O, etc., each of which may be used singly or in combination.

When the nucleating agent exceeds 5% by weight, the crystallization rate becomes rapid, resulting in a sintered body that is not sufficiently densified.

The powder of the above-mentioned glass composition is obtained by, for example, blending and melting each component so that the weight percent composition is within the above-mentioned range, and then rapidly cooling the melt so as not to precipitate crystals to obtain a transparent glass. Although it can be obtained by finely pulverizing it, it may also be obtained by other methods. The particle size of the powder of the glass composition is
Although not particularly limited, it is preferable that the average particle size is 1 to 10 μm. If the average particle size exceeds 10 μm, the surface unevenness of the glass sintered body becomes severe, and when used as a wiring board, the conductor accuracy of the circuit may deteriorate. Furthermore, since the crystallization temperature may become high, sufficient crystal precipitation will not occur if the temperature is 1000° C. or lower, resulting in a sintered body with a low amount of crystals, so there is a possibility that a reduction in dielectric constant cannot be expected. At the same time, the mechanical strength may become low, which may lead to a lack of practicality. On the other hand, if it is less than 1 μm, the crystallization rate of the glass composition may accelerate, and the crystallization may end before sufficient sintering occurs, making it difficult to increase the sintered density. There is.

Examples of the molded body of the powder of the glass composition include, but are not limited to, a green sheet or a stack of a plurality of green sheets. resin to obtain the molded body,
When an organic substance such as a solvent is used, it is preferable to perform pre-firing in advance to remove the organic substance, and then carry out the firing for sintering. Note that the organic substance is not particularly limited, and various types can be used. Moreover, materials other than organic substances may be used, or a molded article may be obtained without using anything.

The conditions for firing the molded body are not particularly limited, but since sintering can be performed at a temperature lower than the melting point of the above-mentioned low-resistance metal material (around 0°C), it is recommended that the molded body be fired at that temperature. This allows printing and firing of low-resistance metal materials at the same time. It does not have to be fired at the same time. The multilayer wiring board is, for example, formed by alternately laminating insulating material layers of the glass sintered body of the present invention and low resistance conductor wiring layers, but is not limited thereto. Applications are not limited to multilayer wiring boards.

Next, the glass sintered body according to the present invention will be explained in detail based on Examples.

Examples 1 to Table 1 (Part 1) and Table 1 (Part 2)
Glass raw materials were prepared to have compositions in the proportions shown in No. 31 and Comparative Examples 1 to 5, and after mixing, they were placed in an alumina crucible and melted at a heating temperature of about 1400°C. The melt thus obtained was dropped into water to obtain a transparent glass composition (frit). This composition was wet or dry milled in a ball mill to give a glass powder with an average particle size of 1 to IO μm.

Polybutyl methacrylate resin, dibutyl phthalate, toluene, etc. were added to this glass powder and kneaded, followed by defoaming treatment under reduced pressure to obtain a slurry. Then, using this slurry, 0.2
* A continuous sheet of mK was produced. After this was dried, it was peeled off from the film sheet and punched out to obtain a green sheet of an appropriate size. Next, through-holes were formed in each green sheet, and a wiring pattern was printed using a low-resistance metal conductor paste. A plurality of green sheets with through holes and wiring patterns formed thereon were laminated and press-molded to form a molded body.

2. This laminated green sheet is heated from room temperature to 500°C.
The temperature was raised at a rate of 5° C./min and held at 500° C. for 2 hours and 45 minutes to thoroughly degrease. After that, 3.3℃/m
Table 1 (Part 1) and Table 1 (Part 2) at the speed of in
Raise the temperature to the specified firing temperature shown in 3.
The laminated green sheets were fired by holding for a certain period of time. Thereafter, the temperature was lowered to 400°C at a rate of 1.8°C/min, and then allowed to cool naturally to obtain a sintered body.

Examples 1 to 31 and Comparative Examples 1 to 5 thus obtained
The dielectric constant and water absorption rate of the sintered bodies were measured, and the results are shown in Table 1 (Part 1) and Table 1 (Part 2). Measurements of dielectric constant were performed at a frequency of IM Hz.

The water absorption rate was measured according to JIS C-2141.

As is clear from Table 1 (Part 1) and Table 1 (Part 2), the sintered bodies of Examples have lower dielectric constants (and have better electrical properties) than those of Comparative Examples. Moreover, the sintered bodies of the examples were all fired at a lower temperature than that of the comparative example, and it can be seen that the sintered bodies of the examples were sufficiently sintered by firing at a temperature of 1000° C. or lower.

〔Effect of the invention〕

As described above, the glass sintered body of the present invention is obtained by firing a molded body of powder of the glass composition having the above composition.
It is sufficiently densified by firing at a low temperature of 1000℃ or less,
It is possible to obtain a sintered body with a low dielectric constant (and even when used as a material for a multilayer wiring board, there is no fear of insulation deterioration due to migration phenomena).

Claims (1)

[Claims] (1) A glass sintered body obtained by firing a molded body of powder of a glass composition containing SiO_2, Al_2O_3 and MgO as main components, the composition of the glass composition being: 40 to 60% by weight of SiO_2; Al_2O_3 is 10 to 40% by weight, MgO is 10 to 40% by weight, and 10 to 30% by weight of the MgO is SrO.
, is substituted with at least one member selected from the group consisting of BaO and CaO, TiO_2, ZrO_2, SnO_2, P_2O_5,
A glass sintered body characterized in that at least one nucleating agent selected from the group consisting of ZnO, As_2O_3 and MoO_3 is contained in a proportion of 5% by weight or less.