JPS63299298A - Multilayered printed board - Google Patents

Abstract

PURPOSE:To eliminate a need for mounting a capacitor use to prevent a variation in a power-supply voltage by a method wherein one out of a pair of adjacent wiring layers is used for a power-supply wiring part and the other is used for a ground while a material between the wiring layers is composed of an insulating material with a high dielectric constant so that the electrostatic capacitance can be increased. CONSTITUTION:This is a four-layer printed-circuit board; a first layer 1 and a fourth layer 4 are used mainly for wiring parts of a signal line; a second layer 2 is used mainly for a power supply; a third layer 3 is used mainly for a ground. In this board, a material between the first layer and the second layer and between the third layer and the fourth layer is composed of an insulating material 5 with a low dielectric constant which is used for a conventional printed-circuit board; the material between the second layer and the third layer is composed of an insulating material 6 with a high dielectric constant. By this setup, it is possible to increase the electrostatic capacitance between a power-supply wiring part in the second layer and a ground wiring part in the third layer while the electrostatic-capacitive coupling between the signal line in the first layer and the power-supply wiring part in the second layer and between the signal line in the fourth layer and the ground wiring part in the third layer is suppressed to be low as in a conventional case.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a multilayer printed circuit board.

[Conventional technology]

A multilayer printed circuit board is a board in which many wiring layers are stacked to achieve higher wiring density, and is an essential element for downsizing single-child devices.

However, by overlapping the wiring layers, capacitance coupling between the wiring layers increases, and there is a possibility that mutual interference of various signals within the substrate may occur.

Therefore, in the conventional multilayer printed circuit board, as shown in FIG. 2, the members between all the wiring layers 21 are made of a low dielectric constant insulating material 22 to keep the capacitance between the wiring layers small.

[Problem that the invention seeks to solve]

Generally, in order to prevent power supply voltage fluctuations, charge storage means is often added between the power supply and ground.

However, in conventional multilayer printed circuit boards, even if the LiE source wiring layer and the land wiring layer are placed next to each other, the capacitance between the power supply wiring and the ground wiring is small, and the capacitance is insufficient as the charge storage means. , it is necessary to mount a capacitor (bypass capacitor), which is disadvantageous in terms of mounting area and is a very problematic point in today's world where high-density mounting is required.

Therefore, the present invention aims to solve these problems.
The purpose is to provide a multilayer printed circuit board that has a large capacitance between the power supply wiring and the ground wiring, and does not require mounting a capacitor to prevent fluctuations in the power supply voltage.

[Means for solving problems]

The multilayer printed circuit board of the present invention is composed of at least three layers, one of which is used mainly for power supply wiring and the other is mainly used for grounding among a pair of adjacent wiring layers, and only the members between the wiring layers have high dielectric properties. It is characterized by being made of a high-density insulating material.

〔Example〕

FIG. 1 shows a four-layer printed circuit board according to an embodiment of the present invention, in which the first layer 1. The fourth layer 4 is mainly used for signal wiring, the second
Layer 2 is mainly used for power supply, and sixth layer 3 is mainly used for ground.

Here, the members between the first layer and the second layer and between the third layer and the fourth layer are made of a low dielectric constant insulating material 5. The members between the second layer and the third layer are each made of an insulating material 6 with a high dielectric constant.

As a result, the capacitance coupling between the signal line on the first layer and the power supply line on the second layer, and between the signal line on the fourth layer and the ground line on the third layer is kept small as before. At the same time, the capacitance between the power supply wiring in the second layer and the ground wiring in the third layer can be increased.

〔Effect of the invention〕

As described above, according to the present invention, the capacitance of the power supply wiring and the ground wiring is large, and the board itself can serve as a bypass capacitor.This makes it unnecessary to mount a bypass capacitor as in the past. Because there is no
This has the effect of enabling even higher density packaging and miniaturization of the board.

[Brief explanation of drawings]

FIG. 1 is a main sectional view showing an embodiment of the multilayer printed circuit board of the present invention. FIG. 2 is a main cross-sectional view of a conventional multilayer printed circuit board (four layers). 1......First layer 2......Second layer 3...Third layer 4......Third layer 4 layers 5...Low dielectric constant insulating material 6...
・・・High permittivity insulating materials and above Applicant Seiko Epson Co., Ltd. Representative Patent Attorney Mogami, ``*<1 other person) Gu' 〆

Claims (1)

[Claims] In a multilayer printed circuit board consisting of at least three or more layers, one of a pair of adjacent wiring layers is mainly used for power supply and the other is mainly used for grounding, and only the members between the wiring layers are made of high dielectric constant insulating material. A multilayer printed circuit board characterized by: