JP2005310895A - Multilayer printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer printed wiring board which can improve the accuracy of capacitor characteristics, by preventing the generation of no stray capacitance. <P>SOLUTION: The multilayer printed wiring board is provided with a capacitor that comprises a first electrode formed in a lower layer of vertically continuous overlapping two layers and a second electrode formed, in parallel with the first electrode inside an upper layer of the two layers with a dielectric in-between. In this case, an interlayer connection conductor from the first electrode is connected to a circuit pattern formed in a layer beneath the lower layer, and an interlayer connection conductor from the second electrode is connected to a circuit pattern formed in the upper layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multilayer wiring board such as a multilayered printed circuit board.

2. Description of the Related Art Conventionally, there is a technique for configuring an electronic circuit by connecting circuit components such as a resistor, a capacitor, a coil, and an IC chip on a printed circuit board with a thin copper wire. In recent years, there has been a demand for higher density electronic circuits on printed circuit boards, and multilayer printed circuit boards that use printed circuit boards in multiple layers to form electronic circuits on each layer and connect each layer using vias are often used. Has been. Patent Document 1 is disclosed as a technique of a multilayer wiring board.
JP-A-5-235554

  Here, a conventional capacitor built in a multilayer wiring board has a circuit pattern ground conductor layer 4 in which an upper electrode 2 on the upper side of two insulating layers is formed on a lower layer as shown in FIG. The lower electrode 1 is connected to a circuit pattern formed in the upper layer by a via or the like. However, in the capacitor configuration as shown in FIG. 2, stray capacitance is generated between the lower electrode 1 and the ground conductor layer 4 due to a potential difference between the lower electrode and the ground conductor layer 4. This stray capacitance has a problem that the self-resonant frequency of the built-in capacitor is lowered. In particular, when the insulating layer is thin, or when the insulating layer is made of a material having a high dielectric constant, the effect of stray capacitance becomes significant and the characteristics of the capacitor are greatly deteriorated.

  Accordingly, an object of the present invention is to provide a multilayer wiring board that can improve the accuracy of capacitor characteristics by not generating stray capacitance.

  The present invention has been made to solve the above-described problems. In the multilayer wiring board, a first electrode formed in the lower layer of two layers that are continuously overlapped in the vertical direction, and a dielectric in the upper layer of the two layers. A multilayer wiring board having a built-in capacitor comprising a second electrode formed in parallel with the first electrode across a body, wherein the first electrode is connected to a circuit pattern formed in a layer below the lower layer The multilayer connection board is characterized in that the interlayer connection conductor from the second electrode is connected to the circuit pattern formed in the upper layer.

  According to the present invention, there is no potential difference between the first electrode and the circuit pattern formed in the lower layer of the two lower layers that overlap in the vertical direction in the multilayer wiring board. For this reason, stray capacitance is not generated between the first electrode and the circuit pattern formed in the lower layer of the lower layer of the two layers that continuously overlap each other in the multilayer wiring board, and the self-resonant frequency is reduced. Can be prevented. That is, it is possible to produce a multilayer wiring board having a built-in capacitor with good capacitance accuracy and frequency characteristics.

  Hereinafter, a multilayer wiring board according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the multilayer wiring board according to the embodiment. In this figure, reference numeral 1 denotes a lower electrode. Reference numeral 2 denotes an upper electrode. 3 is a dielectric. Reference numeral 4 denotes a ground conductor layer. 5A and 5b are vias or through holes (interlayer connection conductors). Reference numerals 6A and 6B denote insulating layers.

  The multilayer wiring board in FIG. 1 shows two continuous upper and lower insulating layers (upper layer 6A and lower layer 6B). First, the lower electrode 1 integrated with the circuit pattern is formed on the surface of the lower layer. An upper electrode 2 is formed in the upper layer in parallel with the lower electrode 1. The lower electrode 1 and the upper electrode 2 are separated from each other with the dielectric 3 interposed therebetween, and a circuit pattern is integrated with the upper electrode 2. The lower electrode 1, the upper electrode 2 and the dielectric 3 constitute a built-in capacitor.

  In the multilayer wiring board of FIG. 1, the circuit pattern integrated with the upper electrode 2 of the built-in capacitor is connected to the circuit pattern formed in the upper layer through the via 5A. The circuit pattern integrated with the lower electrode 2 of the built-in capacitor is connected to the ground conductor layer 4 of the circuit pattern formed in the lower layer below via a via 5B.

  1, the lower electrode 1 of the built-in capacitor and the ground conductor layer 4 are connected by the via 5B, so that no potential difference occurs. For this reason, stray capacitance is not generated between the lower electrode 1 and the ground conductor layer 4, and the reduction of the self-resonance frequency can be prevented. That is, a multilayer wiring board having a built-in capacitor with good capacitance accuracy and frequency characteristics can be manufactured.

It is a figure which shows the structure of the multilayer wiring board by one Embodiment of this invention. It is a figure which shows the structure of the conventional multilayer wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lower electrode 2 ... Upper electrode 3 ... Dielectric 4 ... Grounding conductor layer 5A, 5B ... Via 6 ... Insulating layer 6A ... Insulating layer (upper layer)
6B ... Insulating layer (lower layer)

Claims (1)

A first electrode formed in a lower layer of two layers that continuously overlap each other in the multilayer wiring board;
A second electrode formed in parallel with the first electrode with a dielectric sandwiched between the upper layers of the two layers;
A multilayer wiring board comprising a built-in capacitor comprising:
An interlayer connection conductor from the first electrode is connected to a circuit pattern formed in a layer below the lower layer,
A multilayer wiring board, wherein an interlayer connection conductor from the second electrode is connected to a circuit pattern formed in the upper layer.

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