JPH0425098A - Ceramic multilayer substrate - Google Patents

Abstract

PURPOSE:To prevent the generation of an obstacle among signal lines such as a cross-talk and a delay of signals by forming plural via-holes and plural through-holes on a low-dielectric-constant substrate, whereas filling a high- dielectric material inside the via-holes ahd the through-holes of a necessary number, and further providing a capacitor inside the substrate. CONSTITUTION:A surface conductor 24 electrically connects wirings formed on both sides of a low-dielectric-constant substrate 21. An inner layer conductor 23 composes wirings formed on a surface of said low-dielectric-constant substrate 21 which forms an inner layer substrate, and at the same time, acts as an electrode of a high-dielectric material 22 filling through-holes 26 of the low- dielectric-constant substrate 21, thereby composing a capacitor 28 inside the through-holes 26 and the via-holes 27 together with the high-dielectric material 22.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a ceramic multilayer substrate that can be widely used in circuits of electronic devices and the like.

Conventional technology In recent years, ceramic multilayer substrates have improved thermal conductivity and heat resistance.

Because it has superior properties to organic material substrates in terms of chemical durability, etc., it can be used as an alternative to organic material substrates, and as electronic devices become smaller and more diverse, it can be used as high-density wiring and high-density mounting substrates. It has become widely used2. Furthermore, demand for ceramic multilayer substrates that incorporate passive components such as containers is expected to increase in the future.

A conventional ceramic multilayer substrate will be described below with reference to the drawings.

FIG. 2 is a sectional view showing a part of the manufacturing process of a conventional ceramic multilayer board, and FIG. 3 is a sectional view of a ceramic multilayer board manufactured by the conventional manufacturing method.

As shown in FIG. 2, via holes 2 are formed using a punching machine or the like at necessary locations on a ceramic green sheet 1a which is formed by adding a thermoplastic resin or the like to the inorganic powder having a low dielectric constant as a main component. A conductive layer 3 is provided by filling the inside with a conductive paste by printing or the like. Furthermore, wiring 4 and electrode paste 5 for capacitors are printed using conductive paste on another ceramic green sheet) Ib. In addition, beer holes/I/2 are similarly formed at necessary locations on the high dielectric green sheet 6, which is formed by molding an inorganic powder having a high dielectric constant and adding a thermoplastic resin, etc., to the inorganic powder 3. , - and a conductor layer 3 is provided therein. After sequentially stacking the required number of Green Sea I's thus constructed, the ceramic multilayer substrate shown in FIG. 3 is obtained by firing.

In FIG. 3, 7 is a high dielectric layer, 8 is an electrode, and 9 is a high dielectric layer.
is a capacitor sandwiched between electrodes 8. 10 more
is a via hole, 11 is a through hole, and the high dielectric layer 7
It is electrically connected to the wiring conductor 13 and the electrode 8 provided on the low dielectric constant ceramic layer 12 .

Generally, circuit components and the like are mounted on the ceramic multilayer substrate configured in this way and used in electronic devices and the like.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, if the potentials differ between the electrodes 8 formed on the high dielectric layer 7, an electric capacitance occurs, and therefore a capacitor 9 can be formed.
Electrical capacitance also occurs between wirings connecting the capacitors 9 provided in the high dielectric layer 7'2 and between signal lines, causing signal crosstalk and delay. In addition, when wiring a signal line or the like to the high dielectric layer γ, the wiring conductors 13 provided on the low dielectric constant ceramic layer 12 are connected through through holes)
The via hole /I/1 must be connected through the high dielectric layer 7 as shown in FIG.
There were major problems such as unnecessary capacitance being generated between 0 and Null-Ho/v11.

Furthermore, the capacitor 9 built into the ceramic multilayer board
In order to increase the capacitance of the high dielectric layer 7, it is necessary to increase the number of high dielectric layers 7, and therefore the volume of the high dielectric layer 7 that occupies a large amount of the ceramic multilayer substrate 9. When the body layers 7 are fired at the same time, there is a very serious problem in that cracks occur at the interface between them and delamination occurs.

The present invention is intended to solve the above-mentioned problems, and aims to provide a highly reliable ceramic multilayer board that does not cause problems such as crosstalk or signal delay between signal lines. be.

Means for Solving the Problems Page 5 - 7 In order to achieve the above object, the present invention provides a plurality of via holes and through holes in a low dielectric constant substrate constituting a ceramic multilayer substrate, and provides the required number of via holes and through holes. 4. High dielectric material inside the through hole. J is completely filled and has a structure with a built-in capacitor inside the board.

Sakukawa Therefore, the present invention does not generate unnecessary capacitance due to the two-layer structure, so there is no problem such as crosstalk or signal delay between signal lines, and the high dielectric layer It is also possible to avoid phenomena such as cracks and delamination due to shrinkage strain that occur during simultaneous firing of low dielectric constant ceramic layers.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention.

In the figure, 21 is a low dielectric material made of alumina, glass, etc.
``E-rate board, 22 is a high dielectric material mainly composed of iron-lead-based perovunkai l-4g, 23 is an inner layer conductor, 24 is a surface conductor, and 25 is an electrical connection between the inner layer conductor 23 and the surface conductor 24. The high dielectric material 22 is a through-hole conductor.The high dielectric material 22 is filled in necessary locations of a large number of through holes 26 provided in a low dielectric constant substrate 21 constituting an inner layer substrate.

Next, the operation of the two-layer embodiment will be described. In the two-layer embodiment, the surface conductor 24 is formed on both sides of the low dielectric constant substrate 210 to electrically connect wiring (not shown), and the inner layer conductor 23 is the low dielectric conductor 23 forming the inner layer substrate. At the same time, it constitutes the wiring formed on the surface of the low dielectric constant substrate 21, and acts as an electrode for the high dielectric layer 22 filled in the through holes 26 of the low dielectric constant substrate 21. A capacitor 28 is configured inside the via hole 27.

As described below, according to this embodiment, the capacitor 28 built into the ceramic multilayer substrate does not need to be formed as a green sheet, and can be provided inside the through hole 26 or via hole 27, and the capacitor 28 built in the high dielectric layer 22 The amount can be extremely small compared to the amount of the low dielectric constant substrate 21, so the low dielectric constant JI (
The effect of the difference in shrinkage rate between the plate 21 and the high dielectric structure 22 is small, and problems such as cracks and delamination can be prevented.

In this embodiment, alumina and glass were used as the main components for the 4J of the low dielectric constant substrate 21, but other ceramic materials can be used as long as they have a low dielectric constant. Although iron-lead based perovsky 1- is used as the body material, other dielectric materials can be used as long as they have a high dielectric constant.

Effects of the Invention As described in -1-, according to the present invention, a plurality of via holes and null holes are provided in a low dielectric constant substrate, and the required number of via holes and through holes are filled with a high dielectric structure and laminated sequentially. By doing this, a capacitor is formed inside the multilayer ceramic substrate, so the signal lines do not face each other with a high dielectric layer in between, eliminating problems such as cross daughters and signal delays, and thus reducing wiring density. can be done.

Furthermore, since the high dielectric structure occupies a small proportion of the entire ceramic multilayer substrate, the strain caused by the difference in shrinkage rate with the material of the low dielectric constant substrate is small, and there is an advantage that cracks and delamination between the layers do not occur.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a cefmic multilayer board according to an embodiment of the present invention, Fig. 2 is a sectional view showing part of the manufacturing process of a conventional ceramic multilayer board, and Fig. 3 is a sectional view of the same ceramic multilayer board. be. 21...Low dielectric constant substrate, 22...High dielectric system, 26...Through hole, 27... Via hole, 28... Capacitor.

Claims (1)

[Claims] In a ceramic multilayer substrate formed by laminating a plurality of low dielectric constant substrates, a plurality of via holes and a plurality of through holes are formed in the low dielectric constant substrate, and a required number of via holes and through holes are formed. A ceramic multilayer board filled with a high dielectric material and with a built-in capacitor inside the board.