JPH0642373Y2 - Ceramic multilayer board - Google Patents

Description

[Detailed Description of the Invention] [Outline] In a ceramic multilayer substrate, with respect to ensuring conductivity of via connection portions between layers, in particular, ensure conductivity of via connection portions with respect to various shift elements and increase resistance. For the purpose of prevention, in a ceramic multilayer substrate in which a conductor pattern is formed on a green sheet, a via is filled with a conductor paste, and a land is provided at the end to laminate multiple layers, each via connection part of the green sheet of each layer In addition, the metal pin is configured to be inserted in a straight line over its entire length.

[Industrial application field]

The present invention relates to a ceramic multi-layer substrate, especially between each layer.
Concerning the continuity of via connection.

In recent years, in order to meet the demands for high density, high speed, miniaturization, etc. of printed wiring boards, it has been considered to increase the number of layers, and there are active movements to realize this in a ceramic substrate. As one of the multilayer methods for this ceramic substrate, a green sheet multilayer method in which an alumina green sheet is used, and a conductor pattern is printed on this green sheet is laminated in multiple layers while conducting vias with vias, and baked to integrate. There is.

[Conventional technology]

Therefore, the conventional ceramic multilayer substrate by the green sheet multilayer method has a structure as shown in FIG. 3 (a), for example. That is, reference numerals L ₁ , L ₂ , ... Represent each layer, and when describing one layer L ₁ , the conductor pattern 2 is formed by printing on the surface of the thin green sheet 1. Also, a small diameter via3 is opened in the interlayer connection part of the green sheet 1.
The via 3 is filled with the conductive paste 4, and a land 5 having a larger diameter is provided at the end of the via 3 so as to ensure electrical continuity with the vias in the upper and lower layers. Then, the green sheets 1 of the respective layers L ₁ , L ₂ , ... Are accurately positioned and laminated as shown in the drawing, and are fired.

Here, since the green sheet 1 is fired in a high temperature atmosphere, shrinkage of several% to several tens% occurs after firing. Therefore, the green sheet 1 before firing is preliminarily formed in consideration of shrinkage. The contraction in this case is particularly affected by via
This is a connection portion, and the land 5 is designed to be electrically connected even if the size and the like of the land 5 deviate due to contraction.

[Problems to be solved by the device]

By the way, in the above conventional example, each layer L ₁ , L ₂ ,
Since only the green sheet 1 having the via 3 and the land 5 formed separately is simply laminated, the conductivity is determined only by the positional relationship between the via 3 and the land 5. Here, the vias 3 and the lands 5 of the layers L ₁ , L ₂ , ... Are positioned with high accuracy before firing, but a deviation γ of several tens of μ may occur due to a processing error of each green sheet 1. In addition, the green sheets 1 themselves between the layers may be displaced due to uneven pressure distribution during lamination, or may be displaced due to shrinkage during firing. On the other hand, the size of the land 5 cannot be increased so much due to the restriction of the wiring density. Due to the above factors, in some cases, after firing, the via ₃ of one layer L ₂ is completely separated from the upper and lower layers L ₁ and L ₃ and is disconnected due to various misalignment elements as shown in (b).

Also, since the via 3 is filled only with the conductor paste 4,
Due to the insufficient filling, voids or the like may occur during firing, leading to an increase in resistance and a decrease in reliability.

The present invention has been made in view of the above problems, and an object thereof is to ensure the conductivity of the via connection portion with respect to various displacement elements, prevent an increase in resistance value, and have high reliability. It is to provide a multilayer substrate.

[Means for Solving the Problems]

In order to achieve the above object, the ceramic multilayer substrate of the present invention inserts a metal pin into the via connecting portion of the green sheet of each layer. In this case, in the case where the via connecting portion has one or more layers, A metal pin is inserted and installed along the entire length of each connection part.

[Action]

Based on the above configuration, when the via connection part extends over multiple layers, the vias and lands of each green sheet are positioned and held by the metal pin so that they do not shift, and the via connection part after firing has a small resistance value due to the metal pin. This will ensure continuity.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, symbols L ₁ , L ₂ , ...
1 is a green sheet, 2 is a conductor pattern, 3 is via, 4
Is a conductor paste, 5 is a land, and each green sheet 1 is via3 while filling the via3 with the semi-kneaded conductor paste 4.
The lands 5 are positioned and stacked. Therefore, a thin metal pin 6 is inserted between the land 3 and the land 5 when the green sheets are laminated. Here, one layer of via
At the connecting part 7a, the metal pin 6 is cut to its length and
Inserted in the center of each via3. Via over 2 or 3 layers
In the connecting portions 7b and 7c, the metal pin 6 has substantially the same length as those of the connecting portions 7b and 7c, and penetrates the land 5 in the middle to penetrate two or three vias 3.
The metal pin 6 is inserted and installed so as to straddle between the two or three green sheets 1. The metal pin 6 inserted into the via 3 is supported by the viscosity of the conductor paste 4.

After the green sheets are laminated and pressed at a higher temperature, deviations due to uneven press pressure and deviations due to firing contraction occur. Deviation is regulated. For this reason, at least the via connection portions 7b and 7c, the metal pin 6 together with the via 3 and the land 5 are formed.
Are aligned and held, thus the via connection 7
The conductivity of b and 7c is secured. Also, each connection 7
In a, 7b, and 7c, the metal pin 6 functions as a conductor having a small resistance value.

The metal pin 6 is preferably made of the same material as the conductor paste 4 of the via 3 mechanically and electrically, but is not limited to this. The metal pin 6 may have a cylindrical shape as well as a rod shape, and various shapes and numbers can be considered in consideration of thermal deformation, compatibility with the paste, and the like.

[Effect of device]

As described above, according to the present invention, in the ceramic multi-layer substrate, the metal pin is inserted over the entire length of each via connecting portion to regulate the deviation, so that the disconnection of the via connecting portion after firing is prevented, and the via connecting portion is prevented. Connection reliability is improved.

Since the metal pin in the via portion conducts electricity with a constant small resistance value, the electrical characteristics are improved.

By positioning the via connection part with a metal pin, the land shape can be made smaller, which promotes the improvement of wiring density and improves the workability of stacking. Further, the substrate is locally positioned, and shrinkage and deformation are restricted as a whole, which is advantageous.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a ceramic multilayer substrate of the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, FIG. 3 (a) is a sectional view of a conventional example, and FIG. It is sectional drawing which shows a state. In the figure, 1 is a green sheet, 2 is a conductor pattern, 3 is a via, 4 is a conductor paste, 5 is a land, 6 is a metal pin, and 7a, 7b and 7c are via connecting portions.

Claims (1)

[Scope of utility model registration request] 1. A plurality of layers in which a conductor pattern (2) is formed on a green sheet (1), a via (3) is filled with a conductor paste (4) and a land (5) is provided at an end thereof. In the ceramic multilayer substrate, each via connection part (7a, 7b, 7) of the green sheet (1) of each layer
For each c), a metal multi-layered board in which metal pins (6) are inserted and installed in a straight line over their entire length.