JPH10303609A - Dielectric line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate high volume production of a transmission line which is usable for a multi-layered substrate or semiconductor package through a lamination technology by providing two arrays of a via hole conductor groups in a signal transmission direction at an interval less than a half wavelength of a signal to be transmitted by inserting them into a base body where a low- dielectric-constant and a high-dielectric-constant layer are laminated, and electrically connecting them. SOLUTION: The base body 10 of this dielectric line comprises the low- dielectric-constant layers 1a and 1c and high-dielectric-constant layer 1b. Then the via hole conductors 3 are arranged at the interval (c) in the signal transmission direction X and the interval (c) is less than half as large as the wavelength of the signal to be transmitted through the high-dielectric-contact layer. Further, the via hole conductors 3 are inserted into the base body 10 in the lamination direction to form groups A and B of the via hole conductors 3 in two arrays in the signal transmission direction X. A couple of beltlike conductor layers 2 which are formed on the top surface of the base body 10 are electrically connected to end parts of the via hole conductors 3 appearing on the top surface of the base body 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric line for transmitting high-frequency signals such as microwaves and millimeter waves, and more particularly to a dielectric line built in a wiring board such as a multilayer wiring board or a semiconductor package. It is about.

[0002]

2. Description of the Related Art Conventionally, as transmission lines in the high frequency field,
Waveguides, dielectric waveguides, striplines, microstrip lines, and the like are known. Also, as a dielectric line, an NRD guide is known for its excellent characteristics.

[0003]

However, these have the following problems. First, strip lines or microstrip lines have a very simple structure,
Although suitable for fabrication by a lamination technique, there is a problem that transmission characteristics are degraded in a millimeter wave band of 30 GHz or more.

[0004] On the other hand, waveguides are very excellent in transmission characteristics, but have the disadvantage of being large in size. For example, even a standard rectangular waveguide for 60 GHz has an inner diameter of 3.76 mm × 1.88 mm, which is too large to be applied to a multilayer substrate or a semiconductor package for microwaves or millimeter waves. In this regard, the dielectric waveguide in which the dielectric is clogged has a size of 1 / ε1 / ² , where the relative dielectric constant of the dielectric is ε, so by increasing the relative dielectric constant, , The size of the waveguide can be reduced. However, since it is basically necessary to cover the outside of the dielectric with a conductor wall, it has been difficult to produce the dielectric by a lamination technique.

[0005] In recent years, NRD guides have attracted attention due to their high characteristics, and various research results have been reported. This has a structure very similar to an H guide in which a dielectric strip is inserted between two parallel metal flat plates. H guides are known for their very high transmission characteristics. However, if the line is bent to take the metal plate interval to be １ ／ or more of the wavelength of the transmitted signal, the radiated wave generated at the bent portion cannot be suppressed.
In the case of the NRD guide, since the distance between the metal plates is set to be equal to or less than の of the wavelength of the signal to be transmitted, radiation does not occur at the bent portion and high transmission characteristics are maintained. Thus, NR
Although the D guide has a very simple structure and excellent transmission characteristics, it has not been put to practical use until now.
This was due to productivity problems. In addition, it cannot be integrated with a conventional wiring board, and is difficult to use.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric line which can be used as a transmission line in a multilayer substrate or a semiconductor package and can be easily mass-produced by using a lamination technique.

[0007]

As a result of repeated studies on the above problems, the inventor has found that a large number of electrically connected via holes are used instead of the metal plate used for the H line or the NRD guide. It has been found that, by adopting a structure in which a high dielectric constant layer is sandwiched between low dielectric constant layers, a dielectric line that can be easily manufactured by ordinary multilayering technology and can be built into a high-density wiring board or package can be formed. Invented the invention.

That is, a dielectric line according to the present invention comprises a base formed by sequentially stacking a low dielectric layer, a high dielectric layer and a low dielectric layer, and inserting the base in the stacking direction to form the high dielectric layer. And two rows of via-hole conductor groups formed in the signal transmission direction at an interval c equal to or less than 波長 of the wavelength of the signal to be transmitted. And a pair of strip-shaped conductor layers that are electrically connected to each other.

Here, the distance a between the two rows of via-hole conductor groups is larger than 波長 of the wavelength of the signal to be transmitted in the high dielectric constant layer, and smaller than 波長 of the wavelength of the signal to be transmitted in the low dielectric constant layer. It is desirable that the setting is made smaller.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, reference numerals 1a,
1c is a low dielectric layer, 1b is a high dielectric layer, 2 is a strip-shaped conductor layer, and 3 is a via-hole conductor. Low dielectric layers 1a, 1
The base 10 is formed from the substrate c and the high dielectric constant layer 1b. FIG. 1 is a perspective view so that the conductor can be easily understood.

The low dielectric layers 1a and 1c and the high dielectric layers 1b
Is composed of an organic resin, ceramics, or a composite thereof. In the case of using ceramics, the dielectric constant is generally higher than that of resin. However, the use of ceramic materials having a small dielectric loss even at a high frequency has the advantage of reducing the transmission loss.

[0012] The thickness of the low dielectric layer 1a is t _1, the thickness of the low dielectric layer 1c is t _3, the thickness of the high dielectric constant layer 1b t ₂
It has been.

The via-hole conductors 3 are formed at intervals c in the signal transmission direction X, and the interval c is set to be equal to or less than 波長 of the wavelength of a signal transmitted through the high dielectric constant layer.
The via-hole conductor 3 penetrates the base 10 in the stacking direction, and two rows of via-hole conductor groups A and B are formed in the signal transmission direction X.

A pair of strip-shaped conductor layers 2 formed on the surface of the base 10 are electrically connected to the ends of the via-hole conductors 3 exposed on the surface of the base 10. That is, the base 10
Via-hole conductors 3 are electrically connected to each other by a pair of strip-shaped conductor layers 2 formed on the upper surface and the lower surface, respectively. It is sufficient that the width of the strip-shaped conductor layer 2 is about the diameter of the via-hole conductor 3.

The third group of via-hole conductors A and B have a predetermined distance a
And the via-hole conductors 3 are formed at a predetermined interval c in the signal transmission direction X, that is, the line forming direction. The predetermined interval c is set to an interval equal to or less than の of the wavelength of the signal transmitted through the high dielectric constant layer to form an electric wall. As a result, the same structure as the H guide, that is, the dielectric A body track is formed. In other words, pseudo conductors formed by via-hole conductors 3A and 3B, the upper and lower surfaces of which are formed by low dielectric layers 1a and 1c, and the side surfaces of which are formed at intervals c which are equal to or less than half the wavelength of a signal transmitted through the high dielectric layer. The dielectric line surrounded by the surface is formed.

The above-described dielectric line can be easily manufactured by a conventional lamination technique. For example, a via hole is formed in an organic resin or ceramic sheet having a predetermined thickness for forming a low dielectric constant layer, and the hole is filled with a conductive ink to form a via hole conductor. Then, a strip-shaped conductor layer connected to the via-hole conductor is formed on the lower surface of the organic resin or ceramic sheet by a screen printing method or the like.

In a similar manner, via holes are formed in an organic resin or ceramic sheet having a predetermined thickness for forming a high dielectric constant layer, and the holes are filled with a conductive ink to form via hole conductors. Furthermore, a via hole is formed in an organic resin or ceramic sheet having a predetermined thickness to form a low dielectric constant layer, and conductive ink is filled in the hole to form a via hole conductor, and screen printing is performed on the upper surface of the organic resin or ceramic sheet. A strip-shaped conductor layer connected to the via-hole conductor is formed by a method or the like.

Thereafter, these are sequentially laminated as shown in FIG. 1, and when the dielectric layer is made of a thermosetting resin, it is cured by heating, and when it is a ceramic green sheet, it is laminated and fired. can do.

In a structure in which a high dielectric layer is sandwiched between low dielectric layers, when an electromagnetic wave is fed to the high dielectric layer 1b, reflection occurs at the interface between the upper and lower low dielectric layers 1a and 1c, and the electromagnetic wave is two-dimensionally reflected. Propagation is possible. Even if the via-hole conductors 3A and B are provided, if the distance c between the via-hole conductors 3 is larger than 1/2 of the wavelength of the signal transmitted through the high dielectric constant layer 1b, the electromagnetic wave is transmitted to the via-hole conductors 3A. , B, and also spreads two-dimensionally. However, if the distance c between the via-hole conductors 3 is smaller than 1/2 of the wavelength of the signal transmitted through the high dielectric constant layer 1b, the electromagnetic wave cannot propagate in the direction perpendicular to the transmission line, and Propagated.

Since this dielectric line has a structure having an electric wall on the side, no radiation occurs even if there is a bent portion, and excellent transmission characteristics can be obtained.

As described above, the dielectric line according to the present invention
Basically, electromagnetic waves are reflected at the interface between the low dielectric layers 1a and 1c. However, since electromagnetic waves are not completely confined in the high dielectric layer 1b, they are also distributed to the low dielectric layers 1a and 1c. , But attenuate exponentially in the low dielectric layers 1a and 1c. Therefore, the thicknesses t ₁ and t ₃ of the low dielectric layers 1a and 1c are required to some extent. In particular, the low dielectric constant layer 1
In a and 1c, in order to effectively attenuate electromagnetic waves, t ₁ and t ₃ are made as thick as possible, and t _{2 is set} to λ / 2.
It is desirable to increase the thickness of the high dielectric constant layer 1b as much as possible.

The signal to be transmitted is larger than 1/2 of the wavelength of the signal transmitted through the high dielectric layer in the high dielectric layer 1b, and the signal transmitted through the high dielectric layer is transmitted in the low dielectric layers 1a and 1c. The high dielectric constant layer 1 is set so as to be smaller than half the wavelength.
b, the material constituting the low dielectric layers 1a and 1c is selected, and the distance a between the two rows of via-hole conductors 3A and B is larger than 1/2 of the wavelength of the signal to be transmitted in the high dielectric layer. ,
In addition, by setting the low-k layer to be smaller than half the wavelength of the signal to be transmitted, the electromagnetic wave can be effectively confined in the high-k layer 1b.

In the above embodiment, the base in which the high dielectric layer is sandwiched between the pair of low dielectric layers is described. However, the present invention is not limited to the above embodiment, and the upper surface of the low dielectric layer and An insulating layer may be formed on the lower surface so as to cover the strip-shaped conductor layer 2. That is, the present invention can be applied to a case where a dielectric line is formed inside a substrate.

The materials of the strip-shaped conductor layer 2 and the via-hole conductor 3 may be the same metal or different metals. Further, it is not necessary to be a metal, and any conductor may be used.

FIGS. 3 and 4 show a structure between the low dielectric constant layer 1a and the high dielectric constant layer 1b and between the low dielectric constant layer 1c and the low dielectric constant layer 1c in order to strengthen the electric wall formed by the via hole conductors 3A and 3B. FIG. 4 is a diagram showing an example in which a sub-conductor layer 11 is formed between the sub-conductor layer 11 and a high dielectric layer 1b. The sub-conductor layer 11 is electrically connected to the via-hole conductor 3 like the strip-shaped conductor layer 2.

[0026]

As described above, the present invention provides an unprecedented dielectric line which can be easily manufactured by applying the conventional ceramic lamination technology and can be used from microwave to millimeter wave. The dielectric line for transmitting high-frequency signals such as microwaves and millimeter waves can be built in a wiring board such as a multilayer wiring board or a semiconductor package.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a dielectric line according to the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is a perspective view showing another embodiment of the dielectric waveguide of the present invention.

FIG. 4 is a sectional view of FIG. 3;

[Explanation of symbols]

 1a, 1c: low dielectric constant layer 1b: high dielectric constant layer 2: band-shaped conductor layer 3: via hole conductor 10: base body 11: sub-conductor layer A, B ... Via-hole conductor group

Claims (2)

[Claims] 1. A base in which a low dielectric layer, a high dielectric layer, and a low dielectric layer are sequentially stacked, and a wavelength of a signal transmitted through the high dielectric layer when the base is inserted in the stacking direction and transmitted through the base. / 2 rows of via-hole conductor groups formed in the signal transmission direction at an interval c of not more than / 2, and a pair of strip-shaped conductors formed on the upper and lower surfaces of the base and electrically connecting the via-hole conductors for each row And a layer. 2. The distance a between two rows of via-hole conductor groups is larger than 1/2 of the wavelength of a signal to be transmitted in the high dielectric constant layer.
2. The dielectric line according to claim 1, wherein the low dielectric constant layer is set to be smaller than half the wavelength of the signal to be transmitted.