JP2000278008A - High frequency wiring board - Google Patents

Abstract

(57) [Problem] To increase the reflection loss of a high-frequency signal in a high-frequency input / output unit formed by connecting coplanar lines of a conventional high-frequency wiring board. A first coplanar line formed on an upper surface of a dielectric substrate and a second coplanar line formed on a lower surface of the dielectric substrate in parallel with the first coplanar line. The conductors are opposed to each other with the inner-layer ground conductor 9 interposed therebetween, and the ends of the line conductors 3 and 6 are electrically connected to each other by the through conductors 10. This is a high-frequency wiring board including a high-frequency input / output unit in which ground conductors 4 and 7 are electrically connected to each other by a ground through conductor 11 at a distance of 1/8 to 1 times the wavelength of the signal. The phase shift of the ground is suppressed, and the increase in the reflection loss of the high-frequency signal can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency wiring board having a high-frequency input / output section with improved electrical characteristics.

[0002]

2. Description of the Related Art In a high-frequency wiring board used for a high-frequency circuit board, a high-frequency semiconductor element storage package, a high-frequency semiconductor element mounting chip carrier, and the like, a high-frequency semiconductor element or the like mounted on the upper surface thereof is used. High-frequency transmission lines for transmitting high-frequency signals are formed on the upper and lower surfaces to electrically connect the components for high-frequency wiring of the external electric circuit board on which the high-frequency wiring board is mounted. A high-frequency input / output section is formed by electrically connecting them with a through conductor. The high-frequency wiring board is mounted on the external electric circuit board, and the high-frequency transmission line on the lower surface is electrically connected to the connection line conductor of the external electric circuit board, so that the high-frequency wiring board is mounted and used. Will be done.

As an example in which such a conventional high-frequency wiring board is applied to a package for mounting a high-frequency semiconductor device, there is a package described in, for example, Japanese Patent No. 2605502. This package mounts a package substrate, a package side wall mounted on the substrate in the package, a lid for sealing a cavity formed by the package side wall, and a semiconductor integrated circuit chip provided in the cavity. A die bonding region, an external coplanar line having an internal high-frequency transmission line made of a metal thin film on the surface of a dielectric substrate provided in the cavity, and forming a lead terminal formed of the metal thin film on the bottom portion of the package substrate; In a package composed of an internal high-frequency transmission line and a metal via hole that electrically connects the external coplanar line, the internal high-frequency transmission line formed in the cavity is formed of a coplanar line, and A plurality of metal layers are connected between each ground metal of the external coplanar line. It is characterized in that it has connected by Iahoru.

According to this, since the internal high-frequency transmission line is configured as a coplanar line, the line width of the signal line can be reduced by appropriately selecting the distance between the signal line and the ground metal. The line width can be adjusted to a lower value, the loss can be reduced, and the reflection loss can be reduced.

Further, when the external coplanar line and the internal high-frequency transmission line are connected by a plurality of via holes or via holes having a coaxial structure, high-frequency mismatch is small, and
In addition, it is possible to increase the isolation.

The reason why the coplanar line is used as the high-frequency transmission line is that the pattern width of the signal line on the side (upper surface) on which the high-frequency component is mounted on the high-frequency wiring board and the external electric circuit substrate on the lower surface are used. For the purpose of compensating for the discontinuity with the pattern width of the signal line on the side (lower surface) mounted on the substrate and improving the isolation between the signal lines, it is preferable to connect the coplanar lines as compared with the microstrip line. It is because of that.

[0007]

However, in the high-frequency wiring board applied to the package described in Japanese Patent No. 2605502, a connection between a coplanar line as an internal high-frequency transmission line and a via hole as a through conductor. Between the ground phase at the portion and the ground phase at the connection between the external coplanar line and the via hole, the ground on the front and back surfaces is conducted through the via hole,
The shift occurred due to the long ground path.
Therefore, there is a problem in that reflection of a transmitted high-frequency signal occurs at a connection portion between the internal coplanar line and the external coplanar line, and the reflection loss increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to eliminate a phase shift of the ground at the connection between the coplanar line and the through conductor, and to reduce the reflection loss of a high-frequency signal. It is an object of the present invention to provide a high-frequency wiring board provided with a high-frequency input / output section capable of suppressing the occurrence of the high-frequency wiring board.

[0009]

A high-frequency wiring board according to the present invention comprises a first coplanar line formed on an upper surface of a dielectric substrate for transmitting a high-frequency signal, and a first coplanar line formed on a lower surface of the dielectric substrate. The first coplanar line and the second coplanar line formed in parallel are disposed to face each other with an inner-layer ground conductor formed inside the dielectric substrate interposed therebetween. Electrically connected with an inner layer ground conductor and an insulated through conductor, and at a distance of 1/8 to 1 times the wavelength of the high-frequency signal on both sides in a direction orthogonal to both coplanar lines from the through conductor, A high-frequency input / output unit is provided, wherein the ground conductors of both coplanar lines are electrically connected to each other by a ground through conductor electrically connected to the inner layer ground conductor.

According to the high-frequency wiring board of the present invention, the structure of the high-frequency input / output unit is such that the first and second coplanar lines are arranged opposite to each other with the inner-layer ground conductor formed in the dielectric substrate interposed therebetween. The ground conductors of the two coplanar lines are electrically connected to each other through the ground through conductor electrically connected to the inner-layer ground conductor at the predetermined position from the through conductor that electrically connects the ends of the line conductors of the line. Since the connection part is formed by the through conductor, the inner-layer ground conductor, and the ground through conductor, the ground conductor is arranged around the through conductor to perform impedance matching, and therefore has electrical characteristics close to a coaxial structure. And the high-frequency mismatch can be reduced to reduce the reflection loss. In addition, since an inner-layer ground conductor is formed between the coplanar lines, and the inner-layer ground conductor and the ground conductors of both coplanar lines are electrically connected by the ground through conductor, the ground conductor is in the same plane. Since the phase difference of the ground due to the length of the signal line due to the length of the via hole is eliminated, the phase of the ground at the connection portion between the line conductor and the through conductor can be equalized and the shift can be eliminated. The reflection loss can be suppressed by suppressing the occurrence of signal reflection.

Further, according to the high-frequency wiring board of the present invention, when the lead terminal is attached to the line conductor of the second coplanar line, the pattern width of the line conductor is required to increase the attachment strength of the lead terminal. And the width of the lead terminal are related to each other, the impedance of the second coplanar line and the inner-layer ground conductor are separated to perform impedance matching, so that the line width of the line conductor can be increased. The wearing strength can be increased.

Further, in the high-frequency wiring board according to the present invention, the ground conductor of the first and second coplanar lines extends so as to surround a tip of each of the line conductors. 1 of the wavelength of the high-frequency signal from the through conductor in the extension direction of the transmission direction at the tip of the conductor
The inner layer ground conductor and the extended ground conductor are electrically connected by auxiliary ground through conductors at a distance of / 8 to 1 times.

As described above, the ground conductor extends in the direction of extension of the transmission direction at the tip of the line conductor, and the ground conductor and the inner-layer ground conductor extending at a predetermined position in the direction are electrically connected by the auxiliary ground through conductor. In the case of connection, since the ground conductor wall is formed by providing the ground through conductor in the signal transmission direction, the high-frequency wave from the tip of the line conductor into the dielectric substrate extending in the transmission direction extension direction. Leakage of the electromagnetic field of the signal can be effectively suppressed, and reflection loss of the high-frequency signal at the high-frequency input / output unit can be further suppressed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a high-frequency wiring board according to the present invention will be described with reference to the drawings.

FIGS. 1A and 1B show an embodiment of a high-frequency wiring board according to the present invention. FIG. 1A is a top view, FIG. 1B is a cross-sectional view taken along the line AA ′ of FIG. (c) is a sectional view taken along the line BB 'of (a), and (d) is a bottom view. Each shows the vicinity of the high frequency input / output unit.

In these figures, reference numeral 1 denotes a high-frequency wiring board. Reference numeral 2 denotes a dielectric substrate, 3 denotes a first line conductor formed on the upper surface of the dielectric substrate 2 for transmitting a high-frequency signal, and 4 denotes a first ground disposed on both sides of the first line conductor 3. Conductor, and the line conductor 3 and the ground conductor 4
The coplanar line 5 of FIG. Reference numeral 6 denotes a second line conductor formed on the lower surface of the dielectric substrate 2 in parallel with the first line conductor 3 so that the front end thereof faces the first line conductor 3, and 7 denotes a second line conductor 6. , And a second coplanar line 8 is formed by the line conductor 6 and the ground conductor 7. In this example,
Two first and second coplanar lines 5 and 8 are formed respectively.

Reference numeral 9 denotes an inner-layer ground conductor formed inside the dielectric substrate 2 so as to face the first coplanar line 5 and the second coplanar line 8, and 10 denotes a line conductor of the first coplanar line 5. 3 and second coplanar line 8
And the through conductor 10 is electrically insulated from the inner layer ground conductor 9.

The first coplanar line 5 formed on the upper surface of the dielectric substrate 2 and the second coplanar line 8 formed on the lower surface of the dielectric substrate 2 Opposingly disposed with the inner-layer ground conductor 9 formed therein interposed therebetween, the line conductors 3 of both coplanar lines 5.8 are provided.
The six tips are electrically connected to each other by the through conductor 10 to constitute a high-frequency input / output unit of the high-frequency wiring board 1. In such a high-frequency input / output unit, the line conductor 7 of the second coplanar line 8 also serves as a mounting electrode for connection to an external electric circuit board.

Reference numeral 11 denotes a grounding through conductor, which is electrically connected to the inner layer grounding conductor 9 and has a high frequency signal on both sides in a direction orthogonal to the first and second coplanar lines 5.8 from the through conductor 10. 1/8 (1/8) of the wavelength of
The ground conductors 4 and 7 of the first and second coplanar lines 5.8 are electrically connected to each other at the double distance position.

In this example, the first ground conductor 4 formed on the upper surface of the dielectric substrate 2 and the second ground conductor 7 formed on the lower surface surround the ends of the respective line conductors 3 and 6. , So that a better grounding state can be obtained.

Reference numeral 12 denotes a frame joined to the upper surface of the dielectric substrate 2, and M denotes a mounting portion for electronic components such as semiconductor elements formed on the upper surface of the dielectric substrate 2. By providing the mounting portion M and the frame 12 in this manner, the high-frequency wiring board 1 can be used as an electronic component storage package for storing high-frequency electronic components. Such a high-frequency wiring board 1 can be manufactured by, for example, a ceramic green sheet laminating method or the like. In this case, the dielectric substrate 2 is formed by laminating a plurality of dielectric layers 2a and 2b. At this time, by setting the dielectric layers 2a and 2b to an appropriate thickness, the position of the inner-layer ground conductor 9, that is, the inner-layer ground conductor 9 and the first and second coplanar lines 5.8
Can be set as desired according to the required specifications for the high-frequency input / output unit.

In particular, the position where the inner-layer ground conductor 9 is formed is
When the distance from the first coplanar line 5 is set to be smaller than the distance from the second coplanar line 8, impedance matching can be performed, and the pattern width of the second coplanar line can be increased. This is preferable because the attachment strength of the terminal is increased.

According to such a high frequency wiring board 1 of the present invention, the first and second
The connection between the coplanar lines 5 and 8 can be made to have electrical characteristics close to a coaxial structure by the through conductor 10, the inner-layer ground conductor 9 and the ground through conductor 11, thereby reducing high-frequency mismatch. Return loss can be reduced, and
The phase of the ground at the connection between the line conductors 3 and 6 and the through conductor 10 can be equalized to eliminate the shift, and the reflection loss of the high-frequency signal can be suppressed and the reflection loss can be suppressed.

Here, the position where the ground through conductor 11 is formed is defined by the first and second coplanar lines 5.8 from the through conductor 10.
If the position is closer than 1/8 of the wavelength of the high-frequency signal on both sides in the direction perpendicular to the direction, the capacitive component increases.
A resonance point tends to appear, and manufacturing tends to be difficult. On the other hand, if the position where the ground through conductor 11 is formed is a position farther than one time the wavelength of the high-frequency signal,
Since the inductive component increases, a resonance point tends to appear. Therefore, the position where the ground through conductor 11 is formed should be at a distance of １ ／ to 1 times the wavelength of the high-frequency signal on both sides in the direction orthogonal to the first and second coplanar lines 5.8. It is.

The high-frequency wiring board 1 of the present invention is mounted on the upper surface of an external electric circuit board.
The line conductor 7 of the second coplanar line 8 is connected to the line conductor for connection of the external electric circuit board, and the ground conductor 7 is connected to the ground conductor of the external electric circuit board by a conductive connecting member such as a solder bump or a solder material. By electrically connecting by the used reflow process, the high-frequency wiring board 1 is mounted on the external electric circuit board.

Next, another embodiment of the high-frequency wiring board according to the present invention is shown in FIG. 2 in the same view as FIG. In FIG. 2, (a) is a top view, and (b) is A-
A ′ line sectional view, (c) is a BB ′ line sectional view of (a),
(D) is a bottom view, all showing the vicinity of the high frequency input / output unit. The same parts as those in FIG. 1 are denoted by the same reference numerals.

In these figures, 1 is a high-frequency wiring board, 2 is a dielectric board formed by laminating a plurality of dielectric layers 2a and 2b, and 3 is a first dielectric board formed on the upper surface of the dielectric board 2. Are the first ground conductors disposed on both sides of the first line conductor 3, and 5 are the first line conductors 3 and the ground conductors 4.
And a first coplanar line composed of: Reference numeral 6 denotes a second substrate formed on the lower surface of the dielectric substrate 2 in parallel with the first line conductor 3 so that the front end thereof faces the first line conductor 3.
Is a second ground conductor provided on both sides of the second line conductor 6, and 8 is a second coplanar line 8 composed of the line conductor 6 and the ground conductor 7. In this example, as in the example of FIG. 1, two first and second coplanar lines 5 and 8 are formed.

Reference numeral 9 denotes a first and a second inside the dielectric substrate 2.
The inner layer ground conductor formed so as to face the coplanar lines 5 and 8 of the first coplanar line 5 is a line conductor 3 of the first coplanar line 5.
Are penetrating conductors that electrically connect the tip of the line conductor 6 and the tip of the line conductor 6 of the second coplanar line 8. Reference numeral 11 denotes a ground through conductor, which is electrically connected to the inner layer ground conductor 9 and has a wavelength of a high-frequency signal on both sides in a direction orthogonal to the first and second coplanar lines 5 and 8 from the through conductor 10. 1
The ground conductors 4.7 of the first and second coplanar lines 5.8 are electrically connected to each other at a distance of / 8 to 1 times.

Reference numeral 12 denotes a frame joined to the upper surface of the dielectric substrate 2, and M denotes a mounting portion for electronic components such as semiconductor elements formed on the upper surface of the dielectric substrate 2.

Reference numeral 13 denotes an auxiliary ground through conductor, which connects the first ground conductor 4 formed on the upper surface of the dielectric substrate 2 and the second ground conductor 7 formed on the lower surface to the respective line conductors 3 and 6. , So that a better grounding state can be obtained, and the respective ends of the line conductor 3 of the first coplanar line 5 and the line conductor 6 of the second coplanar line 8 can be obtained. At the distance of 1/8 to 1 times the wavelength of the high-frequency signal from the through conductor 10 in the extension direction of the transmission direction of the inner layer ground conductor 9 and the ground conductor 4.
7 are electrically connected to each other by these auxiliary ground through conductors 13.

According to such a high-frequency wiring board 1 of the present invention, the connection between the first and second coplanar lines 5.8 is connected to the through conductor 10 in the high-frequency input / output section as in the example of FIG. And the inner layer ground conductor 9 and the ground through conductor 11 can have electrical characteristics close to a coaxial structure, thereby reducing high-frequency mismatch and reducing reflection loss. It is possible to equalize the phases of the grounds at the connection portions of the through conductors 3 and 6 to eliminate the shift, and to suppress the occurrence of reflection of the high-frequency signal and the reflection loss. By providing the auxiliary ground through conductor 13 at a predetermined position, the leakage of the electromagnetic field of the high-frequency signal from the tip of the line conductor into the dielectric substrate extending in the transmission direction as described above can be effectively prevented. Thus, the reflection loss of the high-frequency signal in the high-frequency input / output unit can be further suppressed.

Here, if the position where the auxiliary ground through conductor 13 is formed is located at a distance from the through conductor 10 in the extension direction of each of the line conductors 3 and 6 and less than １ ／ of the wavelength of the high-frequency signal, the capacitive component is reduced. Because of the increase, a resonance point tends to appear. On the other hand, when the position where the ground through conductor 13 is formed is located at a position farther than one time the wavelength of the high-frequency signal, the inductive component increases, so that a resonance point tends to appear. Therefore, the position at which the auxiliary ground through conductor 13 is formed is determined by extending the high-frequency wave from the through conductor 10 in the extension direction of the transmission direction at the tip of each of the line conductor 3 of the first coplanar line 5 and the line conductor 6 of the second coplanar line 8. 1 of signal wavelength
It is necessary to set the position at a distance of / 8 to 1 times.

When the ground conductor 4 of the first coplanar line 5 and the ground conductor 7 of the second coplanar line 8 are extended so as to surround the ends of the line conductors 3 and 6, respectively, the first coplanar line 5 The ground conductors 4 and 7 are formed by adjusting the capacitance component so as to minimize the loss when transmitting signals to the second coplanar line 8 through the through conductor 10 and vice versa. At this time, it is preferable that the resistance, the inductor, and the capacitance are formed at matching positions in the entire signal line.

The high-frequency wiring board 1 of the present invention is also mounted on the upper surface of the external electric circuit board and the line conductor 7 of the second coplanar line 8 is mounted.
Is electrically connected to the connection line conductor of the external electric circuit board, and the ground conductor 7 is electrically connected to the ground conductor of the external electric circuit board by a conductive connection member such as a solder bump or a reflow process using a solder material. By
The high-frequency wiring board 1 is mounted on the external electric circuit board.

It should be noted that the present invention is not limited to the above-described embodiments, and various changes and improvements may be made without departing from the spirit of the present invention. For example, in the example of the above-described embodiment, the case where two line conductors are provided as the first and second coplanar lines, respectively, is shown. However, a case where one line conductor is provided or a plurality of line conductors are provided. It may be the case of a port.

Further, a plurality of ground through conductors may be provided near the ground through conductor at a repetition interval of about １ ／ or less of the wavelength of the high frequency signal.
Still further, a plurality of auxiliary ground through conductors may be provided near the auxiliary ground through conductor at a repetition interval of about 以下 or less of the wavelength of the high-frequency signal.

Further, a structure in which a connecting metal member such as a lead terminal or a ball is attached to the line conductor of the coplanar line may be adopted.

[0038]

According to the high-frequency wiring board of the present invention, the first and second coplanar lines are opposed to each other with the inner-layer ground conductor formed in the dielectric substrate interposed therebetween. A high-frequency input / output section formed by electrically connecting the ground conductors of both coplanar lines via a ground through conductor electrically connected to the inner-layer ground conductor at the predetermined position from a through conductor electrically connected to each other; The connection portion can have electrical characteristics close to a coaxial structure by the through conductor, the inner-layer ground conductor, and the ground through conductor, thereby reducing high-frequency mismatch and reflecting light. Loss can be reduced. Also, since an inner-layer ground conductor is formed between the coplanar lines, and the inner-layer ground conductor and the ground conductors of both coplanar lines are electrically connected by the ground through conductor, the ground at the connection between the line conductor and the through conductor is formed. Can be made equal to eliminate the shift, and the occurrence of reflection of the high-frequency signal can be suppressed to suppress the reflection loss.

According to the high-frequency wiring board of the present invention, the ground conductor extends in the direction of extension of the transmission direction at the tip of the line conductor, and the ground conductor and the inner-layer ground conductor extending at predetermined positions in that direction. Is electrically connected to the auxiliary ground through conductor, the leakage of the electromagnetic field of the high-frequency signal from the tip of the line conductor into the dielectric substrate extending in the transmission direction can be effectively suppressed, The reflection loss of the high-frequency signal in the high-frequency input / output unit can be further suppressed.

As described above, according to the present invention, a high-frequency input / output unit provided with a high-frequency input / output unit capable of eliminating the phase shift of the ground at the connection between the coplanar line and the through conductor and suppressing the reflection loss of the high-frequency signal. The wiring board for use was able to be provided.

[Brief description of the drawings]

1A is a top view showing an example of an embodiment of a high-frequency wiring board according to the present invention, FIG. 1B is a cross-sectional view taken along line AA ′ of FIG. 1A, and FIG. FIG. 3D is a sectional view taken along the line BB ′, and FIG.

2A is a top view showing another example of the high-frequency wiring board according to the embodiment of the present invention, FIG. 2B is a cross-sectional view taken along the line AA ′ of FIG. 2A, and FIG. ) Is a sectional view taken along line BB ′, and (d) is a bottom view.

[Explanation of symbols]

 1 high frequency wiring board 2 dielectric board 3, 6 line conductor 4, 7 ground conductor 5 first coplanar line 8 ..The second coplanar line 9 ... the inner layer ground conductor 10 ... the through conductor 11 ... the ground through conductor 13 ... the auxiliary ground through conductor

Claims (2)

[Claims] 1. A first coplanar line formed on an upper surface of a dielectric substrate for transmitting a high-frequency signal, and a second coplanar line formed on a lower surface of the dielectric substrate in parallel with the first coplanar line. The coplanar line is disposed facing the inner layer ground conductor formed inside the dielectric substrate, and the ends of the line conductors of both coplanar lines are electrically connected to each other by a through conductor insulated from the inner layer ground conductor. Connected, and the ground conductors of both coplanar lines are connected to the inner-layer ground conductor at a distance of 1/8 to 1 times the wavelength of the high-frequency signal on both sides in a direction orthogonal to both coplanar lines from the through conductor. A high-frequency wiring board, comprising: a high-frequency input / output unit electrically connected by an electrically connected ground through conductor. 2. The ground conductor of each of the first and second coplanar lines extends so as to surround an end of each of the line conductors, and the penetrating ends of the line conductors extend in an extension direction of the transmission direction. 1 / of the wavelength of the high-frequency signal from the conductor
2. The high-frequency wiring board according to claim 1, wherein the inner-layer ground conductor and the extended ground conductor are electrically connected to each other by auxiliary through-hole conductors at a distance of 8 to 1 times.