JPS6050003B2 - Inorganic composition for insulating ceramic paste - Google Patents

Description

Detailed Description of the Invention The present invention is a composition comprising an insulating glass powder that can be crystallized by heat treatment, mixed with a ceramic powder and a metal oxide, and is mainly used for forming an insulating layer of a multilayer thick film electronic circuit. The present invention relates to an inorganic composition for insulating 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) A conductor circuit is printed using a conductor paste made of platinum (Pt), palladium (Pd), tungsten (W), molybdenum (Mo), and an alloy thereof, and after drying, this is placed in a furnace and fired. In order to form conductor circuits or to obtain finer conductor circuits, conductor circuits are formed by plating, and then insulating glass is used to form an insulating layer that insulates these conductor circuits from the second layer conductor circuit. A method is used in which a paste is applied, placed in a furnace, and fired to form an 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, a second layer conductive circuit is formed by printing and firing the conductive paste so that it fills the connection holes on the surface of the insulating layer. In this way, the third and fourth layer conductor circuits and insulating layers are formed using the same method as necessary, and the desired result is achieved by connecting IC) or u■ to the top layer depending on the application. It was equipped with a multilayer electronic circuit. These insulating layers necessary for forming multilayer thick film electronic circuits can be densely sintered at a temperature of 850 to 950°C, have few pinholes, do not bulge, are acid resistant, have good properties (conductor circuits can be formed by plating) (especially required when molding).

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 that has been conventionally used for this purpose is a crystalline glass type that is crystallized by firing at a temperature of 850 to 950 ° C. ( For example, Special Publication No. 46-42917, Special Publication No. 51
-86168, Special Publication No. 51-10844, Special Publication No. 51
2-34645, etc.). However, the insulating glass paste used in the conventional insulating layer formation mentioned above has its advantages and disadvantages. Plating is often used when there is a limit and a finer line is required.

When an insulating layer is formed by the above method on a conductor circuit formed by these plating methods, the insulating coating layer on the conductor circuit may blister, making it impossible to form the next conductor circuit. Further, even if no blistering occurs, there are problems such as a large number of 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, that is, there is no blistering of the insulating layer on the conductor circuit due to the plating method, excellent adhesion and densification with the conductor, fewer pinholes, and
An object of the present invention is to provide an inorganic composition for an insulating ceramic paste that has low thermal resistance and excellent acid resistance.

In the present invention, in weight percent, SlO24O to 65% (preferably 45 to 60%) Pb
O5-20% (〃 8-18%)B. O33-15
% ( 〃 5-10%) CaO2-13% ( 〃
4-12%) MgOO. 2-10% (〃0.4-8
%) BaOO. 2-10% (〃0.3-8%) Na
2Ol ~ 5% ( 〃 2 ~ 4%) K2Ol ~ 5% (
(1-4%) ZrO2O. 5 to 15% (〃 1 to 10%) for a total of 100%, and among these oxides, the sum of alkaline earth metal oxides including MgO is in the range of 6 to 15%. A glass material having a composition that can be crystallized by heat treatment at a temperature of 1000° C. or lower and AI2O3, MgO.A]203,A1.

to SlO2,3Al. 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 O3.SiO2 and zrO2 in a range of 20 to 60% by weight. Such an inorganic composition for an insulating ceramic paste of the present invention can be manufactured using, for example, the following materials and methods. In other words, when preparing glass, prepare a batch by weighing the raw materials for each component so that it has the target composition, and then heat this batch at 1400 to 1500°C for 1 to 3 hours.
Heat for a period of time to melt and vitrify. The molten glass is cooled with water or poured onto a thick iron plate to form flakes, and the resulting glass pieces are pulverized using an alumina ball mill or the like to obtain glass powder with an average particle size of 0.5 to 4 μm. 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, the present invention, is obtained by adding 20 to 6 weight percent 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. The raw material powder used in this case is expressed in terms of oxides for clarity, but minerals,
Of course, they can be used in the form of oxides, carbonates, hydroxides, etc. by conventional methods.

A vehicle is added to the thus obtained powdered inorganic composition of the present invention, and the mixture is thoroughly kneaded using, for example, a three-roll mill to uniformly disperse the composition 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 terpionel, n-butyl carbitol, butyl carbitol acetate, ethyl carbitol acetate, etc. may be used alone or in combination of two or more. 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, to describe the composition of the glass powder, which is one of the main components of the inorganic composition for an insulating ceramic paste according to the present invention, SiO2 is a network former of glass, and the glass of the present invention is fired. It is a component constituting silicoite (CaO-SiO2) crystals that precipitate when heat treated and crystallized.

At SiO2 <40%, the softening point of the glass becomes too low,
During heat treatment, the glass softens and becomes too fluid before it crystallizes.
At SiO2〉65%, vitrification is difficult, and
A high heat treatment temperature exceeding 1000° C. is required for crystallization.

CaO is also a component constituting the precipitated silicoite crystals. At 2% CaO, the amount of precipitated silicicite 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 electronic circuits, which is not preferable. When CaO>13%, the acid resistance decreases and the glass tends to devitrify when melted. PbO and B2O3 are used as a flux when melting glass. When PlO is 5% and B2O3 is 3%, the solubility of the glass deteriorates. PbO〉20%, B2O3〉12
%, the softening point of the glass becomes too low, causing softening flow before crystallization during heat treatment, making it difficult to sinter and form an insulating coating layer with a fine pattern. BaO and MgO are
It can improve the solubility of glass.

Furthermore, reheating during the formation of the insulating layer contributes to crystallization of the glass and is effective in densification. BaO<
0.2% and MgO<0.2%, the above effect is small. B
If aO>10% and MgO>10%, the thermal expansion coefficient of the glass becomes too large or the heat treatment temperature for crystallization becomes too high. When CaO+MgO+BaO<6%, glass crystallization is insufficient and blistering occurs in the insulating layer formed on the conductor circuit by plating. CaO+MgO+B
When aO>15%, the acid resistance decreases, which is not preferable. It also inhibits denseness. Na2O and K2O can improve the solubility of glass.

Further, although the softening point of the glass is appropriately controlled, if the softening point is below a limited range, there is no effect, and if it exceeds the limited range, the acid resistance deteriorates, which is not preferable. ZrO2 is included to control crystallization of the glass.

With ZrO2 <0.5%, sufficient crystallization cannot be obtained.
If ZrO2>15%, 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 ceramic powder added in place of the glass powder is less than 20% by weight, the insulating layer will be dense, but the surface will become more prone to foaming, and the adhesion with the conductor will deteriorate.
This is not preferable because the thermal resistance becomes larger. Also 6
If it exceeds 0%, a dense insulating layer cannot be obtained at a relatively low temperature of 850 to 1000° C., and the number of pinholes increases and the insulation properties deteriorate. There are various types of ceramic powder as mentioned above, but among them, alumina (Al2O3)
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 be 2 to 4 times as large as that of a single glass layer.

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 The present invention will be described in detail below based on examples.

Example 1 Sj0256.07% by weight (hereinafter simply expressed as %), B2
O36.8%, PbOl6.6%, Na2O2.37%
, K2O2. l7%, MgO4.88%, CaO5.4
%, BaOO. A glass powder having a composition of 21% and 5.5% of ZrO was produced by the above method, and further wet-pulverized for 1 hour using an alumina ball mill and alcohol as a dispersion medium.

After sifting this with a sieve and drying it with alcohol, the average particle size is 0.
．． A glass powder with a particle size of 91P7T1 was obtained. 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 was 48% glass powder and 52% ceramic powder. A predetermined amount of each powder was weighed and 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. To evaluate the obtained insulating ceramic paste, a 50×50×0.87 Tgnt96% Al2O-filled plate was metalized with Au using a plating method to form a lower moving electrode, and the insulating ceramic paste prepared according to the present invention was placed on top of this by a screen. After coating and drying, the material was sintered in an electric furnace at 930° C. for one hour.

The atmosphere during sintering was air, and the sintering cycle (temperature increase, peak temperature, temperature decrease, removal from the furnace) was 6 times. Application of the insulating ceramic paste, drying, and sintering were repeated twice to obtain an insulating layer with a thickness of 40 μm. Au on the surface of the obtained insulating layer
The paste was applied, dried, and baked at 930°C for 8 minutes to form an upper electrode. This was measured at 1 MHz.

The dielectric constant is 8.4. The dielectric loss was 0.0018, and the insulation resistance was 2×10 14 ΩG (AtlOOVDC). When pinholes are measured, the weak leakage current flowing through the insulating layer is measured. If there are many pinholes, the leakage current increases.
Conversely, we took advantage of the fact that the leakage current decreases when there are fewer pinholes.

First, a conductor (Au) is metallized on an Al2O3 substrate under the same conditions as in the present 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 was immersed in a 5% NaCl aqueous solution (electrolyte solution), and the other electrode was a copper plate, immersed in the same aqueous solution, and a direct current voltage (DC) of 1
Apply 0V and measure the leakage current. Ta. The leakage current was 5 μA. To evaluate the adhesion with the plated conductor (Au), an insulating layer with a thickness of 40 pm was formed on the Al2O3 substrate under the same conditions as in this experiment, and an Au electrode 4 was formed on it by plating.
A plurality of ×4 frames were formed.

A copper core (with screws) was bonded onto this electrode using In/Pb solder, a screw hook was screwed into the core, and the adhesion strength was measured using a tensile tester. Average adhesion strength is 2.5k
9/T! It was d. The vehicle-free glass-ceramic powder was pressure-molded at 800k9/c#I and sintered at 930℃-1 in an electric furnace to a diameter of 20TWL.
Thickness 1? A sintered body was obtained.

This was measured and the thermal conductivity was 0.0058Ca1/c! n・
The value of Sec·°C was obtained. Furthermore, no foaming or blistering occurred in the insulating coating layer formed on the Au conductor by plating. Example 2 S10259.4%, 8038.48%, PbOlO.
O%, Na2O2.4%, K2O2.2%, MgO6.
4%, CaO5.4%, BaOO. 22%, ZrO25
．． 46% of glass with a composition of 5% prepared into powder particles with an average particle size of 1.2 μm and 54% of alumina powder with an average particle size of 2.3 μm were mixed and dried in the same manner and under the same conditions as in Example 1. , paste), an insulating layer was formed, and various properties were measured.

As a result, the dielectric constant was 8.5. The dielectric loss was 0.0012, the insulation resistance was 3×10 14 ΩC7X (AtlOOVDC), the leakage current was 10 μA, the adhesion strength was 2.9 k9/Tnltl, and the thermal conductivity was 0.0065 Ca1/0-Sec·°C. Further, there was no foaming or blistering of the insulating coating layer. Example 3
Sj0252.3%, B. O38.8%, PbOl6.
6%, Na2O2.37%, K2O2. O7%, MgO
O. 4l%, BaO6. 1%, CaO5.4%, ZrO
Example 1 was prepared by blending 50% glass powder with an average particle size of 0.79 μm and 50% alumina powder with an average particle size of 3.0 μm, which was produced by a conventional method using glass with a composition of 25.95%. They were mixed, dried, and made into a paste using the same method and under the same conditions to form an insulating layer and measure various properties.

As a result, the dielectric constant was 8. & Dielectric loss 0.0025, insulation resistance 014ΩCm (AtlOOVDC), leakage current μA, adhesion strength 3.0kg/i1 thermal conductivity 0.005
The temperature was AI/[・Sec・℃.

Further, no foaming or blistering of the insulating coating layer on the plated conductor (Au) was observed. Comparative example 1 S10261.34%, B, O36.8%, PbOl6
．． 6%, Na2O2.37%, K2O2. l7%, Mg
OO. 4l%, CaO5.3%, BaOO. 2l%, T
lO2l. 2% ZrO2 and 3.6% ZrO were mixed with 43% glass powder with an average particle size of 0.98 PTrL and 52% alumina powder with an average particle size of 2.3 μm, which was prepared by a conventional method. Mix in the same way and under the same conditions as 1.
It was dried and made into a paste to form an insulating layer, and various properties were measured.

As a result, dielectric constant 8.7, dielectric loss 0.0045, insulation resistance 2.5×1013ΩCln (AtlOOVDC),
The leakage current was 50 μA, the adhesion strength was 1.8 k9/i, and the thermal conductivity was 0.0041 Ca1/d-Sec·°C.

Further, 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, SjO253%, A]2033%, Ll2Ol7
%, MgOl2%, ZrO28.4%, P2O, ll.
It consists only of glass powder with a composition ratio of 9%. Example 1
The paste was made into a paste using the method and conditions described above, applied, and sintered to form an insulating layer, and various properties were measured. As a result, the insulation resistance is 2×1
CPΩ01 Thermal conductivity 0.0022Ca1/Cm-Sec
・°C, leakage current 1200pA1 adhesion strength 0.45k9
It was /i.

In addition, numerous bubbles and blisters occurred in the insulating coating layer on the plated conductor (Au). As explained above, the results of using the inorganic composition for insulating ceramic paste of the present invention show that the inorganic composition for plated conductors (
It is now possible to provide an insulating paste that does not cause foaming or blistering of the insulating coating layer on the Au) and has excellent density, adhesion, and thermal conductivity of the insulating layer, allowing for high-density packaging of thick-film multilayer electronic circuits. This can contribute to improving reliability.

Claims (1)

[Claims] 1 SiO_240-65% PbO5-20% B_2O_3 in weight%
3-12%CaO2-13%MgO0.2-10%Ba
O0.2~10% Na_2O1~5% K_2O1~5%
A glass having a composition in which the total of ZrO_20.5 to 15% is 100%, and among these oxides, the sum of alkaline earth metal oxides including MgO is in the range of 6 to 15%. Materials are 40-80% by weight and Al_2O_3, MgO・Al
_2O_3, Al_2O_3, SiO_2, 3Al_2
20 to 60% by weight of one or more ceramic materials selected from the group consisting of O_3, SiO_2, and ZrO_2
An inorganic composition for an insulating ceramic paste, characterized by having a composition within the range of. 2. The inorganic composition for an insulating ceramic paste according to claim 1, wherein the glass material is a glass material that can be crystallized by heat treatment at a temperature of 1000° C. or lower.