JPH1187916A - Laminated insulating structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously bake by interposing a composite layer which is obtained by sandwiching a glass layer between opposed electrodes via a ceramics layer, thereby preventing a short circuit or migration at the time of baking and integrating them. SOLUTION: A desired electrode 2 is formed by forming a ceramic board 1 by dry press molding, printing Ag paste on the electrode 2 by screen printing, and drying it. Ceramic paste 3 is printed on the entire electrode 3 and dried. Glass paste 4 is printed on the entire surface, and dried. Further, ceramic paste 5 is printed on the overall surface, and dried. Ag paste is printed on the surface and dried to form an electrode 6. Eventually, ceramic paste 7 is printed as a protective layer on the entire surface, and dried. Moreover, in the case of laminating, the step is repeated. After degreasing, it is baked at a predetermined temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating structure for preventing migration in an insulating structure for insulating two opposing electrodes, such as a laminated chip component and a multilayer wiring board.

[0002]

2. Description of the Related Art With the recent demand for smaller and lighter electronic devices, a so-called high-density mounting technology has been developed, in which electronic components or devices are more closely integrated on a substrate at a higher density. In response to this demand, electronic components have been developed into chips, miniaturized, and composited, as seen in multilayer chip components. In addition, further downsizing of electronic devices,
2. Description of the Related Art In order to meet demands for higher density, higher speed, and higher performance, multilayer wiring boards have recently been receiving attention.

[0003]

In these laminated chip components and multilayer wiring boards, Ag and Cu are used as electrode materials, and organic materials such as resins, glass and ceramics are used as insulating materials. . In particular, multilayer chip components and multilayer wiring boards using ceramics are considered to have the best balance between price and performance, and are currently becoming mainstream. As a method of manufacturing a laminated chip component or a multilayer wiring board using this ceramic, the ceramic or electrode material in the form of a sheet or paste is alternately laminated and fired integrally. The ceramic layer will be interposed.

However, in general, ceramics do not melt during firing like glass, so that holes called pinholes are likely to be generated. The interposition and the application of the DC voltage cause a metal movement phenomenon called migration, thereby causing a short circuit. As a countermeasure, a post-treatment of coating the component with a resin or the like is required to prevent intrusion of moisture, and the number of steps has been increased.

[0005] In addition, if the electrode material and the glass are simultaneously fired using glass instead of ceramics as in the prior art, the electrode material and the glass react during firing, and the electrode material diffuses into the glass and short-circuits. The electrode material and glass must be printed and fired for each layer. For example, in the case of manufacturing a multilayer substrate, there is a problem that the cost is increased because firing is performed by the number of layers to be printed. .

SUMMARY OF THE INVENTION In view of the above, the present invention can prevent short-circuiting and migration during firing in an insulating structure that insulates two opposing electrodes, such as a laminated chip component and a multilayer substrate. Moreover, an object of the present invention is to provide an insulating structure that can be integrated and fired simultaneously.

[0007]

According to the present invention, a glass layer is provided between opposing electrodes in a laminated structure formed by appropriately laminating an insulating material and an electrode material and simultaneously firing the insulating material and the electrode material. A laminated insulating structure characterized by interposing a composite layer sandwiched between ceramic layers.

Further, the present invention provides the laminated insulating structure, wherein the ceramic used for the composite layer between the electrodes is ferrite. The ferrite may contain a glass component of 20% by weight or less.

Further, the present invention is the laminated insulating structure, wherein the glass used for the composite layer between the electrodes is an amorphous or crystalline glass. The components of this glass include Li, B, Na, Mg, Al, Si, K,
Ca, Ti, Cr, Mn, Co, Cu, Zn, Ge,
Oxides such as Zr, Ba, Pb and Bi.

Further, the present invention is the laminated insulating structure, wherein the electrode material is Ag or an alloy containing Ag.

Further, the present invention provides a laminated insulating structure wherein the insulating material and the electrode material are formed by screen printing.

Further, in the present invention, the thickness of the ceramic layer after firing is 20 μm or more and the thickness of the glass layer is 10 μm or more in the composite layer.
The laminated insulating structure described in the above.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples and comparative examples of the present invention will be described below in detail. The reason for limiting the insulating structure in the present invention is as follows. When ceramics is used as the insulating material, it can be fired simultaneously with the electrode material, but since ceramics do not melt during firing like glass, holes called pinholes are likely to occur, and short-circuits between the electrodes through these pinholes Or cause migration. In addition, when glass is used as the insulating material, the electrode material and the glass react during firing, and the electrode material diffuses into the glass and causes a short circuit.
For this reason, the electrode material and the glass must be separately fired, which increases the cost.

According to the present invention, as the insulating structure, a glass layer is sandwiched between ceramic layers to form a composite layer, so that the sandwiched glass layer is melted during firing, thereby preventing the generation of pinholes. Since the ceramic layer covering the glass layer prevents the reaction between the electrode material and the glass, simultaneous firing is possible. Thereby, short circuit between electrodes and migration can be prevented.

Glass may diffuse into the ceramic layer during firing, but there is no problem if the content of the glass component in the ceramic is 20% by weight or less. Ag and Cu are mentioned as metals having low specific resistance. However, since Cu must be fired in nitrogen, the cost increases. Therefore, Ag or an alloy containing Ag is desirable as the electrode material. The method for forming the insulating layer and the electrode layer is not particularly limited, but a general method includes screen printing. If the thickness of each ceramic layer after firing is less than 20 μm, the glass may react with the electrodes when diffused into the ceramics. Therefore, the thickness of each ceramic layer is desirably 20 μm or more. More preferably, it is 30 μm or more. When the thickness of the glass layer is less than 10 μm, the possibility of pinholes increases. Therefore, the thickness of the glass layer is desirably 10 μm or more. More preferably, 20
μm or more.

Embodiments 1 and 2 FIG. 1 is a sectional view of an embodiment according to the present invention. In this embodiment, the ceramic substrate 1 is formed by dry press molding, and an Ag paste is printed thereon by screen printing so as to have a width after firing of 200 μm and a thickness of 15 μm, and is dried. Is formed. A ceramic paste 3 is printed on the entire surface of the electrode 2 so as to have a thickness of 20 μm after firing and dried. A glass paste 4 is printed on the entire surface so as to have a thickness after firing of 10 μm and dried. Further, a ceramic paste 5 is printed on the entire surface so as to have a thickness after firing of 20 μm and dried. On this, an Ag paste is printed so as to have a size after firing of 200 μm in width and 15 μm in thickness, and dried to form an electrode 6. Finally, a ceramic paste 7 as a protective layer is printed on the entire surface so as to have a thickness of 25 μm after firing and dried. In the case of further lamination, the above steps may be repeated. After degreasing the multilayer substrate thus manufactured,
It was fired at 890 ° C. Table 1 shows the results of short-circuit and migration tests after firing these samples. A glass using amorphous glass as Example 1
Example 2 using crystalline glass is described as Example 2. Although ferrite is used for ceramics, a dielectric or a mixture thereof may be used.

Comparative Examples 1 and 2 FIG. 2 is a sectional view of a comparative example. The ceramic substrate 1 is formed by dry press molding, and an Ag paste is printed thereon by screen printing so that the dimensions after firing are 200 μm in width and 15 μm in thickness, and dried to form a desired electrode 2. I do. A glass paste 4 is placed on the electrode 2
The whole surface is printed and dried so as to have a thickness after firing of 50 μm. On this, an Ag paste is printed so as to have a size after firing of 200 μm in width and 15 μm in thickness, and dried to form an electrode 6. Finally, a glass paste 8 is printed thereon as a protective layer so as to have a thickness after firing of 25 μm and dried. When further laminating,
The above steps may be repeated. The multilayer substrate thus produced was degreased and then fired at 890 ° C. Table 1 shows the results of short-circuit and migration tests after firing these samples. The glass using amorphous glass is referred to as Comparative Example 1, and the glass using crystalline glass is referred to as Comparative Example 2.

Comparative Example 3 FIG. 3 shows a sectional view of Comparative Example 3. The ceramic substrate 1 is formed by dry press molding, and an Ag paste is screen-printed on the ceramic substrate 1, and the width after firing is 200 μm in width.
A desired electrode 2 is formed by printing and drying to a thickness of 15 μm. A ceramic paste 3 is printed on the entire surface of the electrode 2 so as to have a thickness of 25 μm after firing and dried. Further, a ceramic paste 5 is printed and dried on the entire surface so as to have a thickness of 25 μm after firing. On this, an Ag paste is printed so as to have a size after firing of 200 μm in width and 15 μm in thickness, and dried to form an electrode 6. Finally, a ceramic paste 7 is formed thereon as a protective layer and has a thickness of 2 mm after firing.
Print and dry to 5 μm. In the case of further lamination, the above steps may be repeated. The multilayer substrate thus produced was degreased and then fired at 890 ° C. Table 1 shows the results of the short circuit and migration tests after firing in Comparative Example 3. Ferrite was used as ceramics.

As can be seen from Table 1, in the embodiment of the present invention, simultaneous firing is possible because no short circuit occurs after firing. Further, it can be seen that the embodiment of the present invention does not cause migration and has high reliability. On the other hand, when the insulating layer is made of only glass as in Comparative Examples 1 and 2, a short circuit occurs and simultaneous firing cannot be performed.
Further, for example, when the insulating layer was composed of only ferrite as in Comparative Example 3, migration occurred, which was inappropriate.

[0020]

[Table 1]

As described above, the laminated insulating structure according to the present invention can be fired at the same time because the composite layer in which the glass layer is sandwiched between the ceramic layers is interposed between the opposing electrodes, and has no migration problem. It can be seen that the reliability is high. This is extremely suitable for an insulating structure such as a multilayer chip component and a multilayer substrate. By using this multilayer insulating structure, an excellent multilayer chip component and an excellent multilayer substrate can be obtained at low cost. Note that the composite layer in which the glass layer is sandwiched between the ceramic layers may be partially formed only in a portion where migration is prevented.

[0022]

According to the present invention, short-circuiting and migration during firing can be prevented in an insulating structure portion between two opposing electrodes, such as a laminated chip component and a multilayer substrate, and furthermore, Since they can be integrated and fired at the same time, they can be manufactured at low cost and are very useful.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment according to the present invention.

FIG. 2 is a sectional view of a comparative example according to the present invention.

FIG. 3 is a sectional view of Comparative Example 3 according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic substrate 2, 6 Electrode 3, 5, 7 Ceramic 4 Glass

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akio Uchikawa 70-2 Minamisakaemachi, Tottori City, Tottori Prefecture Tottori Factory, Hitachi Metals, Ltd.

Claims (6)

[Claims] In a laminated structure in which an insulating material and an electrode material are appropriately laminated and the insulating material and the electrode material are simultaneously fired, a composite layer in which a glass layer is sandwiched between ceramic electrodes between opposing electrodes is provided. A laminated insulating structure characterized by being interposed. 2. The laminated insulating structure according to claim 1, wherein the ceramic is ferrite. 3. The laminated insulating structure according to claim 1, wherein the glass is an amorphous or crystalline glass. 4. The laminated insulating structure according to claim 1, wherein the electrode is made of Ag or an alloy containing Ag. 5. The laminated insulating structure according to claim 1, wherein the insulating material and the electrode material are formed by screen printing. 6. The laminated insulating structure according to claim 1, wherein in the composite layer, the thickness of the fired ceramic layer is 20 μm or more, and the thickness of the glass layer is 10 μm or more.