JP2003198213A - Wiring board for high frequency - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency board which can transmit a high frequency signal at a higher frequency band, by reducing a the distance between ground-penetrating conductor and penetrating conductor, and preventing short- circuit between an inner conductor layer and an inner ground conductor layer. <P>SOLUTION: A first and a second coplanar lines are formed on the upper and a lower surfaces of a dielectric board 1, which is provided with a penetrating conductor 4 penetrating a central part of an almost circular inner conductor layer 4a and a plurality of ground-penetrating conductors 5 penetrating central parts of a plurality of almost circular inner ground conductor layers 5a, which are formed at an almost constant interval on a circumference D, having the inner conductor layer 4a as a center. Around the ground-penetrating conductor 5, the inner ground conductor layer 5a is formed in configuration with an annular conductor layer cutting out a part of the penetrating conductor 4 side along a radius R. An angle on the conductor layer side, which a line L passing a center C1 of the penetrating conductor 4 and a center C2 of the ground penetrating conductor 5 makes with respect to the radius R, is 90-120°, a distance between the center C1 and the center C2 is 0.5-0.64 mm and a thickness T of the dielectric layer is 0.1-0.8 mm. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency wiring board provided with a high-frequency input / output unit having improved electrical characteristics. 2. Description of the Related Art A conventional high-frequency wiring board (hereinafter referred to as a high-frequency board) is shown in FIGS. FIG. 4 is a perspective view of the high-frequency substrate, FIG. 5 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 6 is a partially enlarged plan view taken along line BB ′ of FIG. 5. This high-frequency substrate is composed of a dielectric substrate 11 and is used as a high-frequency circuit substrate, a high-frequency semiconductor element storage package, a high-frequency semiconductor element mounting chip carrier, or the like. The first line conductor 12a is electrically connected to a high-frequency component such as a high-frequency semiconductor element mounted on the upper surface of the high-frequency substrate.
A first coplanar line comprising: a first line conductor 12b; a second line conductor 12b; a second coplanar ground conductor layer 13b; Are formed on the upper and lower surfaces, respectively. A through conductor 14 for electrically connecting the first line conductor 12a and the second line conductor 12b,
The same plane ground conductor layer 13a and the second plane ground conductor layer 13b
And a high-frequency input / output unit composed of a ground through conductor 15 that electrically connects the input and output terminals. The through conductor 14 penetrates a substantially central portion of the inner conductor layer 14a having a substantially circular shape in plan view, and is formed from the first line conductor 12a to the second line conductor 12b. As shown in FIG. 6, the ground through conductor 15 is formed at a center C2 of a substantially circular inner-layer ground conductor layer 15a formed at substantially constant intervals on a circumference D centered on the center C1 of the inner-layer conductor layer 14a. And is formed from the first same-plane ground conductor layer 13a to the second same-plane ground conductor layer 13b. [0004] The high-frequency substrate described above comprises a first line conductor 12a.
Through conductor 14 for electrically connecting the second line conductor 12b to the second line conductor 12b
A ground through conductor 15 is formed around the through conductor 14 in order to suppress the reflection loss of the high-frequency signal at the portion. Also, an inner conductor layer formed on each dielectric layer of the dielectric substrate 11
The inner conductor 14a and the inner ground conductor layer 15a have a predetermined width, so that even if misalignment occurs during lamination, the through conductors 14 and the ground through conductors 15 formed on the respective dielectric layers are reliably electrically connected. Can be connected to [0005] However, in the above-mentioned conventional high-frequency board, the recent high-frequency signal for operating a high-frequency semiconductor element or the like has recently become higher in frequency.
When a high-frequency high-frequency signal is transmitted by the first line conductor 12a and the second line conductor 12b, the high-frequency signal leaks from between the ground through conductors 15, the reflection loss increases, and the transmission characteristic of the high-frequency signal increases. There was a problem of deterioration. Therefore, it is conceivable to improve the transmission characteristics of high-frequency signals by electrically connecting the respective ground through conductors 15 so as to form a so-called waveguide.
The strength of the dielectric layer between the penetrating conductor 14 and the ground penetrating conductor 15 is reduced, and the dielectric layer tends to be brittle. That is, when a thermal shock or the like is applied to the high-frequency substrate, the dielectric substrate 11 between the penetrating conductor 14 and the ground penetrating conductor 15 is likely to be damaged such as a crack. It is also conceivable that the distance between the through conductor 14 and the ground through conductor 15 is made as short as possible and the ground through conductors 15 are formed so as not to be electrically connected to each other. However, in this case, the inner conductor layer 14a and the inner ground conductor layer 15a may be electrically connected. In other words, a portion where a high-frequency signal is transmitted and a portion for grounding are electrically short-circuited, so that a problem that transmission characteristics are deteriorated is likely to occur. Accordingly, the present invention has been completed in view of the above problems, and has as its object to shorten the distance between the ground through conductor and the short circuit between the inner conductor layer and the inner ground conductor layer. An object of the present invention is to provide a high-frequency board capable of transmitting a high-frequency signal in a higher frequency band by preventing the high-frequency signal. [0009] The high-frequency substrate of the present invention comprises:
A first line conductor is formed on the upper surface of a dielectric substrate formed by laminating a plurality of dielectric layers, and a first ground conductor layer is formed on both sides of the first line conductor at substantially constant intervals. And a second line conductor formed at a portion of the lower surface of the dielectric substrate facing the first line conductor, and formed on both sides of the second line conductor at substantially constant intervals. A second coplanar line comprising a second coplanar ground conductor layer is provided, and is formed from an end of the first line conductor to an end of the second line conductor and provided between both ends. A through conductor formed through the center of the substantially circular inner conductor layer formed, and a plurality of inner ground conductor layers formed at substantially constant intervals on a circumference centered on the inner conductor layer. And each of the first A high-frequency wiring board comprising a plurality of grounded through-conductors formed from the surface grounded conductor layer to the second same-plane grounded conductor layer, wherein the inner-layer grounded conductor layer has an annular conductor around the grounded through-conductor. The conductor layer is formed so that a layer has a shape obtained by cutting a part of the through conductor side along a radius, and a straight line passing through a center of the through conductor and a center of the ground through conductor and the radius. And the distance between the center of the through conductor and the center of the ground through conductor is 0.5 to 0.64 m.
m, and the thickness of the dielectric layer is 0.1 to 0.8 mm. According to the present invention, since the distance between the ground through conductor and the through conductor can be made extremely short and the short circuit between the inner conductor layer and the inner ground conductor layer can be prevented by the above configuration, a high frequency signal of a higher frequency band can be obtained. Can be transmitted with low loss. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The high-frequency substrate of the present invention will be described in detail below. 1 is a perspective view of a high-frequency substrate according to the present invention, FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. 1, and FIG. 3 is a partially enlarged plan view taken along line BB ′ of FIG. In these figures, 1 is a dielectric substrate, 2a and 2b are formed on the upper and lower surfaces of the dielectric substrate 1, and a first line conductor, a second line conductor, and 3a and 3b through which a high-frequency signal is transmitted are: On both upper and lower surfaces of the dielectric substrate 1, both sides of the first line conductor 2a and the second
A first ground conductor layer and a second ground conductor layer formed on both sides of the line conductor 2b at substantially constant intervals. The first line conductor 2a and the first coplanar ground conductor layer 3a form a first coplanar line, and the second line conductor 2b and the second coplanar ground conductor layer 3b.
Thus, a second coplanar line is formed. Note that the first line conductor 2a and the first same-plane ground conductor layer 3a are not electrically short-circuited, and the second line conductor 2b and the second
Is also formed so as not to be electrically short-circuited. Reference numeral 4 denotes a through conductor for electrically connecting an end of the first line conductor 2a and an end of the second line conductor 2b, and 5 denotes a first same-plane ground conductor layer 3a and a second The ground through conductors 4a connecting to the same plane ground conductor layer 3b are formed on each dielectric layer, and the inner conductor layers connecting the through conductors 4 of each dielectric layer are formed on each dielectric layer. This is an inner ground conductor layer that connects the ground through conductors 5 of each dielectric layer. The first coplanar line and the second coplanar line are electrically connected to the through conductor 4, the inner conductor layer 4a, the ground through conductor 5, and the inner ground conductor layer 5a. A high-frequency board on which high-frequency components are mounted is configured. The through conductor 4 is formed from the end of the first line conductor 2a to the end of the second line conductor 2b, and penetrates substantially the center of the inner conductor layer 4a having a substantially circular shape in plan view. It is formed. In addition, a plurality of ground through conductors 5
Are formed at substantially constant intervals around the inner conductor layer 4a.
The substantially central portions of the plurality of inner-layer ground conductor layers 5a formed on the circumference D (FIG. 3) around the center a are respectively extended from the first same-plane ground conductor layer 3a to the second same-plane ground conductor layer 3b. It is formed so as to penetrate. In the case of FIG. 3, the interval between the inner ground conductor layers 5a is 72 ° in terms of the angle between the center C2 of the ground through conductor 5 with respect to the center C1 of the through conductor 4.
In terms of the interval on the circumference D between the centers C2 of the ground through conductors 5,
About 0.64mm (diameter of ground through conductor 5 is about 0.2mm)
The distance is preferably about 0.25 mm or more on the circumference D between the inner ground conductor layers 5a. In this case, breakage of the dielectric substrate 1 can be effectively prevented. More preferably, the interval on the circumference D between the inner-layer ground conductor layers 5a is
The thickness is preferably about 0.5 mm (the diameter of the ground through conductor 5 is about 0.1 mm) or more, and if it is less than 0.5 mm, cracks easily occur in the dielectric layer between the ground through conductors 5. The first, other than the through conductor 4 and the ground through conductor 5,
Line conductor 2a, second line conductor 2b, first same-plane ground conductor layer 3a, second same-plane ground conductor layer 3b, inner-layer conductor layer 4a, and inner-layer ground conductor layer 5a are made of tungsten (W),
A metal paste obtained by adding and mixing an organic solvent and a solvent to a powder of molybdenum (Mo), manganese (Mn), etc. is mixed with a raw material powder to be a dielectric substrate 1 by adding and mixing an appropriate organic binder and a solvent. The paste is applied to a ceramic green sheet formed by a doctor blade method or a calender roll method in a desired shape in advance by a conventionally known screen printing method, and then sintered at a high temperature of about 1600 ° C. Be produced. On the other hand, the through conductors 4 and the ground through conductors 5 are provided at desired positions on the ceramic green sheets.
A through hole serving as the ground through conductor 5 is formed.
An organic solvent is added to a powder of W, Mo, Mn, or the like, and a metal paste obtained by adding and mixing the solvent is filled, and the first line conductor 2a, the second line conductor 2b, the first same-plane ground conductor layer 3a, Second
Of the same plane ground conductor layer 3b, inner conductor layer 4a, and inner ground conductor layer 5a. The dielectric substrate 1 is appropriately selected from alumina (Al ₂ O ₃ ) ceramics, aluminum nitride (AlN) ceramics, and the like according to characteristics such as the dielectric constant and the coefficient of thermal expansion. In the present invention, as shown in FIG. 3, the inner ground conductor layer 5a has a shape in which an annular conductor layer is formed by cutting a part of the through conductor 4 side along the radius R around the ground through conductor 5. The angle between the straight line L passing through the center C1 of the through conductor 4 and the center C2 of the ground through conductor 5 and the radius R on the conductor layer side is 90 to 120 °.
In FIG. 3, L1 is a line segment on the conductor layer side of the straight line L. In other words, in the present invention, the angle between the line segment L1 and the radius R is
90-120 °. Thereby, the distance between the ground through conductor 5 and the through conductor 4 can be made extremely short, and a short circuit between the inner conductor layer 4a and the inner ground conductor layer 5a can be prevented, so that a high frequency signal in a higher frequency band is transmitted. it can. When the angle is less than 90 °, the conductor layer of the inner ground conductor layer 5a is small, so that if there is any displacement of the ground through conductor 5 formed on each dielectric layer of the dielectric substrate 1, it is possible to displace it. In addition, the ground through conductor 5 and the inner ground conductor layer 5a are not electrically connected, and the ground potential is not strengthened. 120
When the angle exceeds °, the inner conductor layer 4a and the inner ground conductor layer 5a may be electrically short-circuited, and the transmission characteristics of high-frequency signals deteriorate. Even if the inner ground conductor layers 5a are partially short-circuited, the transmission characteristics of high-frequency signals do not deteriorate, but the strength between the penetrating conductor 4 and the ground penetrating conductor 5 is reduced to make them brittle. Easy to be. That is, when a thermal shock or the like is applied to the high-frequency substrate 1 in this case, the dielectric substrate 1 between the penetrating conductor 4 and the ground penetrating conductor 5 is liable to be damaged such as a crack. The ground through conductor 5 is formed on the inner conductor layer 4a.
It should be formed on the circumference D at substantially constant intervals around the through conductor 4 so as not to cause a short circuit. Ground through conductor 5
If the interval is not substantially constant, the transmission characteristics of the high-frequency signal tend to deteriorate. In other words, the ground through conductor 5 has a strong ground potential wall around the through conductor 4, and has a pseudo-coaxial structure close to a coaxial structure to improve the transmission characteristics of high-frequency signals and reduce transmission loss. Can be smaller. In the present invention, the center C1 of the through conductor 4
And the distance between the center C2 of the ground through conductor 5 is 0.5 to 0.64.
mm. Thereby, the ground through conductor 5 and the through conductor 4
Can be made very short, and a high-frequency signal in a high frequency band can be transmitted with lower loss. If the distance is less than 0.5 mm, the distance between the through conductor 4 and the ground through conductor 5 becomes very short, so that cracks easily occur in the dielectric layer between the ground through conductors 5 during drilling. Also, 0.64mm
When the distance exceeds the distance, the distance from the through conductor 4 to the ground through conductor 5 becomes large, which is the same as the distance from the conventional through conductor 4 to the ground through conductor 5, and the transmission characteristics of high frequency signals in a high frequency band are improved. Disappears. The thickness T of one dielectric layer is 0.1 to 0.8.
mm. If the thickness is less than 0.1 mm, it becomes difficult to fabricate the dielectric layer itself and print and laminate the conductor pattern. On the other hand, when the thickness exceeds 0.8 mm, the thickness T of the dielectric layer becomes too large, so that it becomes difficult to form a hole. Further, in the present invention, a ground conductor layer different from the inner ground conductor layer 5a is formed in the inner layer so as to fill the gap between the ground conductors 5 around the through conductor 4 with the metallized layer. The conductors 5 may be electrically connected to each other in the inner layer. In other words, the portion formed by filling with the metallization layer is preferably formed from the circumference D where the inner ground conductor layer 5a around the ground through conductor 5 is located to the outer portion. as a result,
Since the grounding function of the entire high-frequency substrate 1 is further enhanced, high-frequency characteristics in a high-frequency band can be stabilized. Then, I is placed on the upper surface of the high-frequency substrate 1 of the present invention.
A high-frequency component such as a C, LSI, or semiconductor laser (LD) is mounted via an adhesive such as solder, and an electrode pad of the high-frequency component and the first line conductor 2a are electrically connected by a bonding wire. , A second line conductor 2b on the lower surface of the high-frequency substrate 1, and a second ground conductor layer 3b on the same plane.
Are connected to the connection line conductor and the ground conductor layer of the external electric circuit board via an adhesive such as solder, respectively.
The high-frequency component is connected to the external electric circuit board via the high-frequency board 1 so that high-frequency signals can be input and output in a higher-frequency band. The high frequency band referred to in the present invention is 1 to 100 GHz.
It is a high frequency band of about z (gigahertz) and a millimeter wave band, and is preferably used in a band of about 1 to 80 GHz. This is because in a high-frequency band exceeding 80 GHz, a high-frequency signal is easily affected by an external magnetic field, resulting in an increase in noise and loss. More preferably, the frequency is about 1 to 40 GHz. It should be noted that the present invention is not limited to the above-described embodiment, and that changes and improvements can be made without departing from the scope of the present invention. For example, the high-frequency substrate 1 of the present invention may be used as a high-frequency signal input / output unit that is a part of a semiconductor package. According to the present invention, a first line conductor and a first line conductor formed on both sides of the first line conductor at substantially constant intervals on the upper surface of a dielectric substrate formed by laminating a plurality of dielectric layers are provided. A first coplanar line made of one ground conductor layer on the same plane is provided, and both sides of the second line conductor and the second line conductor formed at a portion of the lower surface of the dielectric substrate facing the first line conductor; A second coplanar line formed of a second same-surface ground conductor layer formed at substantially constant intervals,
A through conductor formed from an end of the first line conductor to an end of the second line conductor and penetrating a center portion of a substantially circular inner layer conductor layer provided between both ends; Each of the plurality of inner-layer ground conductor layers formed at substantially constant intervals on the circumference centered on the conductor layer penetrates the center portion thereof, and is formed from the first same-plane ground conductor layer to the second same-plane ground conductor layer. A plurality of grounded through conductors, and the inner ground conductor layer is formed so that an annular conductor layer has a shape obtained by cutting a part of the through conductor side along the radius around the grounded through conductor. The angle of the conductor layer side between the straight line passing through the center of the through conductor and the center of the ground through conductor and the radius is 90 to 120 °, and the angle between the center of the through conductor and the center of the ground through conductor is The distance is 0.5 ~ 0.64mm,
And by the thickness of the dielectric layer is 0.1 to 0.8 mm,
Since the distance between the ground through conductor and the through conductor can be made very short and the short circuit between the inner conductor layer and the inner ground conductor layer can be prevented, a high-frequency signal in a higher frequency band can be transmitted with low loss.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a high-frequency board according to the present invention. FIG. 2 is a cross-sectional view of the high-frequency substrate taken along line AA ′ in FIG. FIG. 3 is a partially enlarged plan view of the high-frequency board taken along line BB ′ of FIG. 2; FIG. 4 is a perspective view of a conventional high-frequency board. FIG. 5 is a sectional view of the high-frequency substrate taken along line AA ′ of FIG. 4; FIG. 6 is a partially enlarged plan view of the high-frequency board taken along line BB ′ of FIG. 5; [Description of Signs] 1: Dielectric substrate 2a: First line conductor 2b: Second line conductor 3a: First same-plane ground conductor layer 3b: Second same-plane ground conductor layer 4: Through conductor 4a: Inner layer conductor layer 5: Ground through conductor 5a: Inner layer ground conductor layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/46 H05K 3/46 Z

Claims (1)

1. A first line conductor and a first line conductor formed on both sides of the first line conductor at substantially constant intervals on an upper surface of a dielectric substrate formed by laminating a plurality of dielectric layers. A first coplanar line formed of one coplanar ground conductor layer, a second line conductor formed at a portion of the lower surface of the dielectric substrate opposed to the first line conductor, and the second line; A second coplanar line composed of a second coplanar ground conductor layer formed at substantially constant intervals on both sides of the conductor is provided, and an end of the first line conductor is connected to an end of the second line conductor. And a through conductor formed through the center of a substantially circular inner conductor layer provided between both ends and formed at substantially constant intervals on a circumference centered on the inner conductor layer. The center of the multiple inner conductor layers In high frequency wiring board and a plurality of ground vias formed toward the second identical plane ground conductor layer from the first same plane ground conductor layer with which penetrates,
The inner-layer ground conductor layer is formed so that an annular conductor layer has a shape obtained by cutting a part of the through conductor side along a radius around the ground through conductor, and the center of the through conductor and the An angle on the conductor layer side between the straight line passing through the center of the ground through conductor and the radius is 90 to 120 °, and a distance between the center of the through conductor and the center of the ground through conductor is 0.5 to 0.64 mm. And the thickness of the dielectric layer is
A high-frequency wiring board having a thickness of 0.1 to 0.8 mm.