JPS5954106A - Inorganic composition for insulating ceramic paste - 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 The present invention is a composition in which an insulating glass powder that can be crystallized by heat treatment is mixed with a ceramic powder and a metal oxide. The present invention relates to an inorganic composition for ceramic paste.

Conventionally, the most common method for manufacturing multilayer thick film electronic circuits, etc. is to deposit gold (Au), silver (A) on a ceramic substrate such as alumina.
, g), platinum (PT), palladium (Pd), tungsten (W), molybdenum (Mo), and a conductor paste made of these alloys to print a conductor circuit, dry it, and then put it in a furnace and fire it. p that formed a conductor circuit.
In order to obtain 1 or even finer conductor circuits, conductor circuits are formed by a plating method, and then an insulating glass paste is applied to form an insulating layer that insulates these conductor circuits from the second layer conductor circuit, and then the conductor circuits are placed in a furnace. A method is used in which an insulating layer is formed by pouring and firing the insulating layer. In this case, when applying the insulating glass paste, it is necessary to leave a connection hole connecting the first layer conductor circuit and the second layer conductor circuit. Next, t1')'Y is printed and fired so that the contact holes on the surface of the insulating layer are filled with the conductive paste to form a second layer conductor circuit.

In this way, the third and fourth layer conductor circuits and insulating layers are formed using the same method as necessary, and a desired multilayer electronic circuit is formed by connecting ICs or LSIs to the top layer depending on the application. It was implemented.

The insulating layers necessary for forming these multilayer thick film electronic circuits are 850
It can be sintered densely at temperatures of ~950°C, has few pinholes, does not bulge, and is acid resistant (especially required when forming conductor circuits by plating). There is a strong demand for materials that meet the requirements of high withstand voltage, low thermal resistance, and low dielectric constant. The inorganic composition for insulating glass paste for forming an insulating layer, which has been conventionally used for such purposes, is
A type of crystalline glass that crystallizes by firing at a temperature of 850 to 950°C is used (for example, Japanese Patent Publication No. 46-42917, Japanese Patent Publication No. 51-86168).
No., Special Publication No. 51-10844, Special Publication No. 52-3464
Publication No. 5, etc.).

However, the insulating glass paste used in the conventional insulating layer formation described above has both advantages and disadvantages. 100μ
The limit is about m, and when smaller lines are required, plating is often used. When an insulating layer is formed by the above method on a conductor circuit formed by these plating methods, blistering occurs in the insulating coating layer on the conductor circuit, making it impossible to form the next conductor circuit. Further, even if no blistering occurred, there were problems such as many pinholes, insufficient acid resistance, poor adhesion to the formed conductor, and high thermal resistance. Therefore, there is a need to develop an inorganic composition for an excellent insulating ceramic paste for forming an insulating layer used in forming a high-density packaging ceramic multilayer thick film electronic circuit.

The purpose of the present invention is to eliminate these problems, namely:
Inorganic inorganic paste for insulating ceramic paste that does not cause blistering of the insulating layer on the conductor circuit due to the plating method, has excellent adhesion and densification with the conductor, has few pinholes, has low thermal resistance, and has excellent acid resistance. An object of the present invention is to provide a composition.

The present invention has a Stow of 40 to 65% (preferably 45 to 60%) in weight%.
) PbO 5-20% (〃 8-18%) B, 0.
3-12% (〃 5-10%) OaO2-13%
(s 4-12%) MgO0,2-10% (tt
Q, 4-8%) BaOO, 2-10% (110,
3~8%) Na20 i-5% (//2~
4%) K2O1-5% (〃1-4%) Zr0.
0.5-15% (// 1-10%) total 1
00%, and among these oxides, the sum of alkaline earth metal oxides including MgO is in the range of 6 to 15%, and at a temperature of 1000°C or less. A glass material that can be crystallized by heat treatment and AJlt 03, M-g O・A11t Os,
A11t Os・St 02, 3 hit Os・S
In,.

An inorganic composition for an insulating ceramic paste is obtained, which has a composition containing at least one ceramic material selected from the group consisting of Zr 02 in a range of 20 to 60% by weight (5).

Such an inorganic composition for an insulating ceramic paste of the present invention can be manufactured using, for example, the following materials and methods. That is, in preparing glass, the raw materials of each component are weighed to prepare a batch so as to have a target composition, and this batch is heated at 1400 to 1500° C. for 1 to 3 hours to melt and vitrify. The molten glass is cooled with water or poured onto a thick iron plate and formed into flakes, and the resulting glass pieces are pulverized using an alumina ball mill or the like to obtain an average particle size of 0.5 to 4.
A glass powder of μm size is obtained. Further, the ceramic powder is suitably a fine powder having an average particle size of 0.3 to 5 μm.

A homogeneous mixed powder of glass powder and ceramic powder, that is, a homogeneous mixed powder of the present invention, is obtained by blending 20 to 60% by weight of the ceramic powder to the glass powder obtained by the above method and wet-mixing it with an alumina ball for 1 to 3 hours. An inorganic composition for insulating ceramic paste is obtained.

For clarity, the raw material powders used in this case are expressed in terms of oxides (6), but of course they can be used in the usual manner in the form of minerals, oxides, carbonates, hydroxides, etc. It is.

A vehicle is added to and mixed with the powdered inorganic composition of the present invention thus obtained, and the mixture is thoroughly kneaded using, for example, a five-roll mill, and is uniformly dispersed to obtain an insulating ceramic paste having a viscosity suitable for printing. In the present invention, there are no limitations on the components of the vehicle. As the binder, commonly used binders such as ethyl cellulose and polyvinyl butyral are sufficient, and it is convenient to form a 5 to 15% by weight solution using a solvent. As the solvent, β or α terpineol, n-butyl carpitol, butyl carpitol acetate, ethyl carpitol acetate, etc. may be used alone or in combination of two or more types.

Next, in the present invention, the reason why the blending ratio of the glass powder and the ceramic powder of the inorganic composition for an insulating ceramic paste and the composition of the glass powder are limited as described in the claims will be explained.

First, let us talk about the composition of the glass powder, which is one of the main components of the inorganic composition for insulating ceramic paste according to the present invention. It is a component constituting the silicoite (OaO.5i02) crystals that precipitate when oxidized. When 8i02<40%, the softening point of the glass becomes too low, and the glass softens and flows too much before being crystallized during heat treatment.

When 8 t 02 > 65%, vitrification is difficult and a high temperature of over 1000° C. is required for the heat treatment temperature for crystallization. OaO is also a component constituting the precipitated silicoite crystals. CaO<2% is not preferable because the amount of silica precipitated is small and blistering occurs in the insulating coating layer formed on the conductor circuit by the plating method for high-density mounting ceramic multilayer thick film circuits. OaO＞13%
In this case, the acid resistance decreases and the glass tends to devitrify when melted. PbO and B,03 are used as a flux when melting glass. PbO<5%, E, 03<
At 3%, the solubility of the glass deteriorates. PbO>20%
, B, O.

>12%, the softening point of the glass becomes too low, and during heat treatment, softening flow occurs before crystallization, making it difficult to sinter and form a fine pattern insulating coating layer.

BaO and MgO can improve the solubility of glass.

In addition, BaO contributes to the crystallization of the glass by reheating during the formation of the insulating layer and is effective for densification.
(The above effect is small at 0.2% and MgO<0.2%.

When T]aO) is 10% and MgO>10%, the thermal expansion coefficient of the glass is too large and the heat treatment temperature for crystallization is too high.

When OaO+MgO+EaO<6%, crystallization of the glass is insufficient and blistering occurs in the insulating layer formed on the conductor circuit by plating. OaO+MgO+ BaO>15
%, acid resistance decreases and is not preferred. There is also a force that inhibits densification.

Na2O and Ni20 can improve the solubility of glass. Further, although the softening point of the glass can be moderately adjusted, if it is below a limited range, there is no effect, and if it exceeds the limited range (9), the acid resistance deteriorates, which is not preferable.

Zr 02 is included to control the crystallization of the glass. With ZrO2 <0.5%, sufficient crystallization cannot be obtained. If ZrO2>1s%, the glass tends to devitrify when melted, making vitrification difficult, which is not preferable.

By replacing the ceramic powder, which is another main component of the inorganic composition for an insulating ceramic paste, with the glass powder, it is possible to promote crystallization during heat treatment of the composition consisting of the glass powder and the ceramic powder. It is possible to provide effects such as fluidity caused by residual glass after crystallization, suppression of foaming on the surface of the insulating layer, reduction of thermal resistance, acid resistance, and densification. If the amount of ceramic powder used instead of glass powder is less than 20% by weight, the insulating layer will be dense, but the surface will become more prone to foaming, the adhesion with the conductor will decrease, and the thermal resistance will become worse. It's nice that it's getting bigger. Also, if it exceeds 60%, 850-10
A dense insulating layer cannot be obtained at a relatively low temperature of 00°C,
Pinholes increase and insulation deteriorates.

(10) As mentioned above, there are various types of ceramic powder, but among these, alumina (A40s) is a substance with high thermal conductivity, and when this is used as a ceramic powder, the thermal conductivity of the formed insulating layer will increase. is 2 compared to a single glass layer.
~4 times the size.

In particular, as the density of multilayer thick film circuits increases, an inorganic insulating layer with high heat dissipation properties is inevitably required, and in this sense, it is preferable to use alumina.

Examples of the present invention will be listed below and will be explained in detail based on the examples.
0.6.8%, PbO16.6%, Na2O2.3
7%.

K, 02.17%, MgO4, 88%, CaO5,
4%.

A glass powder having a composition of 00.21% Ba and 25.5% Zr was produced by the method described above, and further pulverized for 16 hours using an alumina ball mill with alcohol as a dispersion medium. This was sized with a sieve and then dried with alcohol to obtain a glass powder having an average particle size of 0.91 μm. As the ceramic powder, alumina powder having an average particle size of 1.5 μm was used. The blending ratio of glass powder and ceramic powder is 48% glass powder and 52% ceramic powder. A predetermined amount of each powder was weighed, mixed in an alumina ball mill for 3 hours using alcohol as a dispersion medium, and then the alcohol was dried to obtain a homogeneous glass-ceramic mixed powder. The vehicle was a 5% solution of ethyl cellulose, and α-terpineol was used as the solvent. 30% vehicle and 70% glass-ceramic mixed powder were thoroughly kneaded using a three-roll mill, and the powder was uniformly dispersed in the vehicle to form a paste.

For evaluation of the obtained insulating ceramic paste, 50X
50X0.8mmt 96%A11t Au on Os substrate
was metalized by a plating method to form a lower electrode, on which the insulating ceramic paste prepared according to the present invention was applied with a screen, dried, and then sintered in an electric furnace at 930° C. for 10 minutes. The atmosphere during sintering was air, and the sintering cycle (temperature rise, peak temperature, temperature fall, removal from the furnace) was 60 minutes. Application of the insulating ceramic paste, drying, and sintering were repeated twice to obtain an insulating layer with a thickness of 40 μm. An Au paste was applied to the surface of the obtained insulating layer, dried, and baked at 930° C. for 8 minutes to obtain an upper electrode.

This was measured at I MHz. Dielectric constant is 8.4, dielectric loss is O, 0O18%, insulation resistance is 2 x 10”Ωcrr
t(atloovDa).

The measurement of pinholes takes advantage of the fact that when measuring the weak leakage current flowing in an insulating layer, the leakage current increases when there are many pinholes, and conversely, the leakage current decreases when there are few pinholes. First, a conductor (Au) is metallized on an M2O substrate under the same conditions as in this embodiment described above, and an insulating layer with a thickness of 40 μm is formed thereon, and a part of the metallization is used as an electrode. This is a 15% Na0 aqueous solution (electrolyte)
The other electrode was a copper plate, and the other electrode was immersed in the same aqueous solution, and a direct current voltage (DC) IOV was applied to measure the leakage current. Leakage current was 5 μA.

To evaluate the adhesion with the plated conductor (Au), an insulating layer with a thickness of 40 μm was formed on the Altos substrate under the same conditions as in this experiment, and a plurality of 4×4 (13) Au electrodes were placed on top of it by plating. Formed. A copper core (with screws) was bonded onto this electrode with In/Pb solder, a screw hook was screwed into this core, and the adhesion strength was measured using a tensile tester. The average adhesion strength was 2.5 kg/1 m2.

80% of the above glass ceramic powder without vehicle
Pressure molded at 0 kg/cfI and heated at 930°C in an electric furnace.
- A sintered body with a diameter of 20 m and a thickness IM was obtained by sintering for 10 minutes. This was measured and the thermal conductivity was 0.00580m//m-5
Obtain the value of ec・℃. Furthermore, no foaming or blistering occurred in the insulating coating layer formed on the Au conductor by plating.

Example 2 8i0□59.4%, B, 0.8.48%, pboi
o.

%, Na2O2, 4%, 02.2%, Mg06.4
%.

Oao 5.4%, Ba00.22%, ZrO
46% of glass with a composition of 25.5% prepared to a powder particle size of 1.2 μm in average particle size and 54% alumina powder with an average particle size of 2.3 μm were mixed in the same manner and under the same conditions as in Example 1. , dry, paste, form an insulating layer, and apply various properties (1).
4) Sex was measured.

As a result, dielectric constant 8.5, dielectric loss 0.0012, insulation resistance 3 x 10"9m (at 100VDO), leakage current 10μA, adhesion strength 2.9kg/ttan2
, the thermal conductivity was 0.0065 °C. Further, there was no foaming or blistering of the insulating coating layer.

Example 3 Sin, 52.3%, B2O3 3.8%, Pb01
6.6%.

Na2O2, 37%, K2O2, 07%, MgO
O,41,%.

BaO6.1%, C! a05.4% + Zr0.5.
Average particle size of 95% glass produced by conventional method: 0.7
50% glass powder of 9 μm and 50% alumina powder of average particle size 3.0 μm were mixed, dried, and made into a paste in the same manner and under the same conditions as in Example 1 to form an insulating layer. The property was measured.

As a result, the dielectric constant was 8.3, and the dielectric loss was 0.0025. The insulation resistance was 4 x 10"9m (at 100VDO), the leakage current was 40μA, the adhesion strength was 3.0kg/B2, and the thermal conductivity was 0.00520ab~Psec・℃. Also, the insulation coating layer on the plated conductor (Au) No foaming or blistering was observed.

Comparative example 1 810□61. ．． 34%, B, 0.6.8%, PbO
16.6%.

Na2O2, 37%, 02.17%, MgO0,
41%.

0a05.3%, Ba00.21%, 'l'1o21.
This was carried out by blending 48% of glass powder with an average particle size of 0.98 μm produced by a conventional method using glass with a composition of 2%, Zr0° and 3.6%, and 52% of alumina powder with an average particle size of 2.3 μm. The mixture was mixed, dried, and made into a paste using the same method and conditions as in Example 1 to form an insulating layer, and various properties were measured.

The results were as follows: dielectric constant 8.7, dielectric loss 0.0045, insulation resistance 2.5 x 1013 Ωm (atlooVD (3), leakage current 50 μA, adhesion strength 1.8 kg/2, thermal conductivity 0.00410 al/cs. ℃. Also, many bubbles and blisters occurred in the insulating layer on the plated conductor (Au).

Comparative Example 2 Conventionally, crystallized glass has been used as an inorganic material in an insulating paste for thick film lamination. For example, 810153%.

) Jt Os 3% + L12017%, MgO1,2
%, ZrO28.4%, P,0I111.9%. This is done using the method of Example 1.
It is made into a paste under certain conditions, applied, and sintered to form an insulating layer.
Various properties were measured.

As a result, insulation resistance 2X10'Ωα, thermal conductivity 0.00
220al/crn ・see "C, leakage current 12
00μA1 adhesion strength was 0.45 kg/il'+2. In addition, numerous bubbles and blisters occurred in the insulating coating layer on the plated conductor (A, u).

As explained above, as a result of using the inorganic composition for insulating ceramic paste of the present invention, the occurrence of foaming and blistering of the insulating coating layer on the plated conductor (Au) was observed compared to the conventional crystallized glass-based insulating paste. This makes it possible to provide an insulating paste with excellent insulating layer density, adhesion, and thermal conductivity, which contributes to higher density packaging and improved reliability of thick-film multilayer electronic circuits. can.

Agent Bentakushi Susumu Hara (17)

Claims (1)

[Claims] 5iot 40-65%, pbo 5-20%E in weight%
x 03 3-12%, □a O2-13%Mg
O0,2~10S, BaOO,2~101Na,0
1-5%, 01-5% Zr0. 0.5-15
% K so that the total is 100%, and among these oxides, alkaline earth ・5i02 containing MgO
1. An inorganic composition for an insulating ceramic paste, characterized by having a composition containing 20 to 60% by weight of one or more ceramic materials selected from the group consisting of: (1)