JPS61242950A - Composition for ceramic substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a ceramic composition suitable for a multilayer wiring board on which electronic circuits such as resistors and conductors are formed in multiple layers.

``Conventional technology'' Electronic components with multilayer circuits are manufactured by alternately printing circuits and insulating layers on a substrate previously formed by sintering, such as the alumina substrate 7, and then firing them. After type 1, a circuit is printed on an unsintered ceramic substrate, and the circuits are stacked so that they do not touch each other.
There is a second type that is produced by pressing and then sintering. In the case of the ml type, unevenness occurs in the insulating layer formed thereon due to the influence of the circuit, and the unevenness becomes larger as the layer increases. As this unevenness increases, it becomes difficult to print the next circuit on it, and this is one of the rules for the number of laminated layers.Normally, the limit for the first type is 5 to 6 layers. .

On the other hand, in the second type, one circuit is always printed on a nearly flat substrate, so there are no rules like the first type, and it is possible to manufacture products with a large number of layers. , higher density integration can be achieved.

As the ceramic composition used for this second tie≠ substrate, there is one in which alumina powder and glass powder of IEiwt% or less are fixed with an organic binder.

[Problems to be solved by the invention] However, in these conventional products, the sintering temperature is 150
Since the temperature is extremely high at 0°C to 1600°C, the materials constituting one circuit must be made of expensive materials such as W and No, which do not deteriorate at such sintering temperatures, and must be fired in a reducing atmosphere, resulting in poor workability. Ta.

The present invention was made as a result of research to solve the difficulties of the second type of ceramic for substrates. The purpose is to provide a composition.

[Means for Solving the Problems] Namely, 1. The present invention uses glass powder of 25 to 65%, alumina powder of 0 to 80%, and forsterite powder of 5 to 60% by weight.
%, and the glass powder is essentially Si in weight %.
O2 25~TO, Al2O34~15°820325
-45 and BaO0.5-30.

As mentioned above, the composition according to the present invention can be sintered at an extremely low temperature of less than 100°C, so it has excellent workability and can be used as a single circuit material as well as Au, Ag-, which is widely used in thick film technology. Pastes such as Pd, old, and Cu can be applied, making them easy to obtain. Furthermore, the sintered body satisfies the following physical properties required for a multilayer wiring board. That is, it has high bending strength, good thermal conductivity, low dielectric constant, high insulation resistance, does not deteriorate circuit materials, and has excellent moisture resistance.

The reasons for the limitations in the composition of the present invention are as follows.

If the glass powder content is less than 25% by weight, the sintering temperature will be high, making it difficult to perform sintering at a low temperature, which is the objective of the present invention.On the other hand, if the glass powder content exceeds 65% by weight, the sintered body will bend. It is more desirable for the glass powder to be in the range of 30 to 50% by weight within the above range, which is undesirable due to decreased strength and moisture resistance.

Although alumina powder is not an essential component, adding it increases the thermal conductivity of the sintered body, improving heat dissipation when used as a multilayer wiring board, and reducing the dielectric loss tangent, so it is particularly desirable for high frequencies.

However, addition of more than 60% is undesirable because the sintering temperature increases, and the preferred amount is 10 to 50% by weight within the above range. - As forsterite powder, 1g2Sj04, which is usually used as a solid solution containing Mg2SiO4 as a main component and a trace amount of Fe25iOs, can be used, as well as pure 1g2Sj04. If the amount of forsterite powder is less than 5% by weight, the sintered body will become loose and the moisture resistance will decrease, which is undesirable. If it exceeds 60% by weight, the sintering temperature will become high, which is not preferable. Forsterite is within the above range. 5-50%
is more desirable.

The glass frit in the present invention preferably has the following composition in terms of forming a sintered body with a low 1M electrical conductivity and excellent bending strength and moisture resistance, that is, SiO2 25 to 65 AI2034 expressed as %. It has a composition of ~15820325~45Ran0.5~30. The reason for this composition limitation is as follows.

If the SiO2 content is less than 25%, the dielectric constant of the sintered body becomes too high, and if it exceeds 65%, the sintering temperature becomes too high, both of which are undesirable.More preferably, it is in the range of 35 to 50%.

If Al2O3 is less than 4%, the moisture resistance of the sintered body will be poor;
If it exceeds 15%, devitrification may occur during the manufacture of glass lift, which is not preferable, and more preferably 5 to 5%.
The range is 13%.

B2O3 is a flux, and if it is less than 25%, the sintering temperature will become too high, and if it exceeds 45%, the chemical stability of the glass will decrease, which is not preferable, and more preferably 30 to 4
The range is 0%.

BaO has the effect of improving the meltability during the production of Himi sfrito. If it is less than 0.5%, the effect is small;
If it exceeds 0%, the dielectric constant of the sintered body becomes too large. It is preferably in the range of 5 to 25%.

It is preferable to add the following components to the glass powder according to the present invention in addition to the above-mentioned components, since this can improve the meltability in the manufacture of the glass powder. However, if the above components are too large, the dielectric constant becomes too high. Since the propagation loss in the high frequency region increases, it is desirable to add the following amounts of each component: Na2O + K2O + Li2O
<1%, ZnO+CaO+NgO+SrO<5
Weight%.

In the present invention, the particle size of each powder such as glass is not particularly limited, and a particle size of about 0.5 to 5 μm is used.

The composition of the present invention is one in which each powder is mixed in the above proportions, and a multilayer wiring board using the composition is manufactured, for example, as follows.

An organic binder and a plasticizer solvent are added to the composition of the present invention and kneaded to form a paste. As the organic binder, polyvinyl butyral, as the plasticizer, dioctyl phthalate or polyethylene glycol, as the solvent, toluene, alcohol, etc., which are all commonly used, can be used.

Next, this paste is formed into a sheet and further 60 to 80
An unsintered sheet, a so-called green sheet, is formed by drying at a temperature of about °C.Next, a predetermined circuit is printed on one side of this green sheet by the thick film method, and then it is laminated.Next, this is pressed. After combining the
Fire and sinter the green sheet and circuit. The product manufactured in this manner has circuits laminated in multiple layers with an insulating substrate interposed therebetween.

[Example] A composition was prepared by mixing glass powders shown in the upper row of Table 1 and glass powders 1 to 20 produced by a conventional method, and then mixing fillers of the type and amount shown in the lower row of the same table with Kamiji J glass powder. Obtained. Note that the amount of glass powder in each sample is the remainder of the filler.

Moreover, positive numbers 17 to 20 are comparative examples.

Next, polyvinyl butyral as an organic binder, dioctyl phthalate and polyethylene glycol as plasticizers, and toluene and alcohol as solvents were added and kneaded to give a viscosity of 10,000 to 30,000 cp.
I made a paste of 0.s and then added this paste to about 0.
After forming a sheet with a thickness of 5 ms, it was dried at 80 to 80°C for about 2 hours.The sheet was then heated at a rate of 300°C/hr and finally fired for 1 hour at the firing temperature listed in Table 2 for sintering. The sheet was inserted. The dielectric constant, dielectric loss tangent, coefficient of thermal expansion, and moisture resistance of this sintered sheet were measured, and the results are shown in Table 2. In the same table, the mark 0 for moisture resistance indicates that the weight loss was less than 1% when immersed in hot water at 100°C for 2 hours, and the mark X indicates that the weight loss was 1% or more.

In addition, for No. 18.19, the physical properties were not measured because the green sheet became powdery and a sintered sheet could not be obtained.

The bending strengths listed in Table 2 are the average values of 10 samples measured as follows.

The sintered sheet was cut into pieces with a length of 10 mm and a length of 50 m, which were arranged in layers at a constant distance of L40. It was placed on two fulcrums, and a load was applied to one point between the fulcrums at a rate of 0.5 mm/min to determine the load P at which it broke. From these values, bending σ was calculated using the following formula.

PL σ=□ (t is the thickness of the sheet) 2wt As is clear from Table 2, the composition according to the present invention has a
It can be fired at temperatures below 0°C, and the fired sheet has excellent moisture resistance. In addition, the strength dielectric constant and S expansion coefficient have characteristics that can be used as a multilayer circuit board.

[Effects of the Invention] According to the present invention, the substrate can be fired at a low temperature and the fired substrate has excellent moisture resistance, so when manufacturing a multilayer circuit element, a 6x-element with little change in characteristics over time can be obtained. It is expected to be. Furthermore, the electrical properties such as bending strength are sufficient for use as a multilayer circuit board.

Claims (2)

[Claims] (1) Consisting of 25-65% glass powder, 0-60% alumina powder and 5-60% forsterite powder in weight%, the glass powder is essentially SiO_22 in weight%
5-70, Al_2O_34-15, B_2O_325
-45 and BaO0.5-30. (2) The glass powder is essentially SiO_ in weight percent.
230-50, Al_2O_35-13, B_2O_3
30-40 and BaO5-25.