JP2001135899A - High frequency printed circuit board and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high frequency printed circuit board and its manufacture which can reduce a reflection or a loss of signals transmitted between printed circuit boards without using a coaxial cable or a high frequency connector. SOLUTION: This device comprises a first signal line 2 which is formed on a first printed circuit board 1 and constitutes a micro strip line, a second signal line 6 which is formed at the opposite side of the first signal line on a second printed circuit board 5 and constitutes a micro strip line, a signal electrode 11 which electrically connects the first and the second signal lines by continuing in the thickness direction of the printed circuit board at a terminal of the second printed circuit board, ground patterns 3, 4, 7 and 8 formed on the first and the second printed circuit boards putting the signal electrode between both sides of the first and the second signal lines, through holes 12 formed through the second printed circuit at the inside of the ground patterns, and ground electrode 17 which electrically connects each first and second ground pattern being formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-frequency printed circuit board suitable for a high-frequency circuit.

[0002]

2. Description of the Related Art Conventional high-frequency printed wiring boards include:
For example, there is one described in JP-A-6-37412. 9 and 10 are cross-sectional views of the printed wiring board described in that patent publication. In FIG. 9, 1a is a printed wiring board, 2a is a signal line formed on the printed wiring board 1a, and 4a is formed on the printed wiring board 1a so as to protrude from the top surface of the signal line 2a with the signal line 2a interposed therebetween. The ground line 4b is a ground surface formed on the surface of the printed wiring board 1a opposite to the signal line 2a, and 6 is a through hole formed in the printed wiring board 1a for connecting the ground line 4a and the ground surface 4b. Here, the signal line 2a forms a microstrip line and a coplanar line with the ground surface 4b on the lower surface of the printed wiring board 1a and the ground lines 4a located on both sides to stabilize the characteristic impedance, 4a and the ground plane 4b are connected by a through hole 6 to stabilize the ground. In FIG. 10, 3 is a signal electrode connected to the signal line, and 16 is a coaxial cable. Here, in order to transmit a signal to another substrate or the like, a signal electrode 3 connected to a signal line is formed by a through hole, and a coaxial cable 1 is formed.
In addition to connecting the signal line 6 to the signal electrode 3, the outer conductor of the coaxial cable 16 is connected to the ground line 4a to stabilize the characteristic impedance at the connection, thereby reducing signal reflection and loss.

[0003]

However, since such a conventional high-frequency printed wiring board has no electrode on its end face, it cannot be connected to another printed wiring board 1a or connected to another substrate or the like. Therefore, since signal electrodes are formed in the printed wiring board 1a with through holes, there is a problem that a coaxial cable 16 and a high-frequency connector are required. Accordingly, the present invention has been made to solve such a problem, and a novel high-frequency printed wiring that can reduce reflection and loss of a signal transmitted between a plurality of printed wiring boards without using a coaxial cable or a high-frequency connector. An object of the present invention is to provide a board and a method for manufacturing the board.

[0004]

According to a first aspect of the present invention, there is provided a high-frequency printed wiring board comprising: a first printed wiring board;
A second printed wiring board mounted on the first printed wiring board; a first signal line formed on the first printed wiring board to constitute a microstrip line; A second signal line formed on the printed wiring board on the opposite side of the first signal line to constitute a microstrip line; and a second printed wiring board at an end of the second printed wiring board. Signal electrodes for electrically connecting the first and second signal lines continuously in the thickness direction, and on both sides of the first and second signal lines, respectively, so as to sandwich the signal electrode; The first and second printed wiring boards formed on the first and second printed wiring boards
And a second ground pattern, and a through hole is formed in the second printed wiring board inside the first and second ground patterns to electrically connect the first and second ground patterns, respectively. And a ground electrode.

A high-frequency printed wiring board according to a second aspect of the present invention includes a first printed wiring board and a second printed circuit mounted on the first printed wiring board and having a concave portion formed at an end. A wiring board, a first signal line extending inside the recess and formed on the first printed wiring board to constitute a microstrip line, and the first signal on the second printed wiring board A second signal line formed on the opposite side of the line to constitute a microstrip line, and the end of the concave portion of the second printed wiring board continuously in the thickness direction of the second printed wiring board. First
And a signal electrode for electrically connecting the second signal line;
First and second formed on the first and second printed wiring boards, respectively, in the vicinity of the recess on both sides of the first and second signal lines, respectively, so as to sandwich the signal electrode. Forming through holes in the ground pattern and the second printed wiring board inside the first and second ground patterns, respectively,
And a ground electrode for electrically connecting the second ground pattern.

According to a third aspect of the present invention, in the high-frequency printed wiring board, a conductive layer is formed inside or outside the second ground pattern in the concave portion. .

A high-frequency printed wiring board according to a fourth aspect of the present invention is the high-frequency printed wiring board according to any one of the first to third aspects, wherein the through-hole is an elongated through-hole.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a high-frequency printed wiring board, comprising the steps of: forming copper layers on both sides of the printed wiring board; Arranging holes, forming second through holes between the through holes, and etching the opposing ground pattern including the first through holes and the signal line including the second through holes; Forming a conductive layer on the inner wall of the first and second through holes; and forming a through hole at the end of the printed wiring board of the first through hole and the second through hole. And forming a notch in the printed wiring board through the substrate, and placing the printed wiring board on another printed wiring board.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 of a high-frequency printed wiring board according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic perspective view of a high-frequency printed wiring board according to the present invention. In FIG. 1, 1 is a first printed wiring board, 2 is a signal line formed on the printed wiring board 1,
Reference numerals 3 and 4 denote ground patterns formed on the printed wiring board 1 on both sides of the signal line 2 at a constant interval from the signal line 2. Reference numeral 5 denotes a second printed wiring board, 6 denotes a signal line extending on the printed wiring board 5 in the same direction as the signal line 2 on the printed wiring board 1, and 7 and 8 denote a predetermined interval from the signal line 6. These are ground patterns formed on the printed wiring board 5 and on the ground patterns 3 and 4 on both sides of the signal line 6, respectively.
Reference numeral 9 denotes the signal line 2 exposed at the end of the printed wiring board 5,
A notch formed to cover the ground patterns 3 and 4;
Reference numeral 10 denotes a connection pad formed by soldering or the like on the printed wiring board 1 for electrically connecting the signal line 2 and the signal line 6, and 11 denotes a connection pad for electrically connecting the signal line 2 and the signal line 6. The signal electrodes are continuous in the thickness direction of the printed wiring board 5, and are formed of a conductive member in a side surface of the cutout 9 formed in the printed wiring board 5 or in a groove formed in the side surface. Therefore, signal line 2
The signal lines 6 are electrically connected through the signal electrodes 11 and the connection pads 10.

On the other hand, the signal line 2 on the printed wiring board 1 and the signal line 6 on the printed wiring board 5
Constitute a microstrip line by a ground pattern (not shown) formed inside or on the back of the printed wiring board 1 and the printed wiring board 5, respectively. Reference numeral 12 denotes a plurality of through holes formed in the printed wiring board 5, which are formed inside the printed wiring board 1 and the ground patterns 3, 4, 7 and 8 formed on the printed wiring board 5. These through holes may have a cylindrical shape as shown in FIG. 1 or an elongated hole shape as shown in FIG. A conductive through-hole layer is provided in each of the cylindrical through-holes 12 or the elongated through-holes to electrically connect the ground patterns 3 and 7, and 4 and 8, respectively. It constitutes an electrode.

As described above, the signal line 2 on the printed wiring board 1 and the signal line 6 on the printed wiring board 5 constitute a microstrip line.
The signal flowing through the upper signal line 6 is transmitted to the signal line 2 on the printed wiring board 1 through the signal electrode 11. At this time, the plurality of ground electrodes connected to the ground patterns 3, 7, 4, and 8 make the signal electrodes 11 on both sides in the vicinity of the signal electrodes 11 in the thickness direction of the printed wiring board 5.
It is configured to sandwich. This means that the structure of the signal electrode 11 is a pseudo coaxial line structure. Therefore,
The change in the characteristic impedance at the signal electrode 11 is reduced, so that signal reflection and loss can be reduced.

[0012]

Embodiment 2 Next, Embodiment 2 of the present invention.
Will be described with reference to the drawings. FIG. 3 is a schematic perspective view of the second printed wiring board 5 as viewed from above, and FIGS. 4A to 4F show a manufacturing method for manufacturing the second printed wiring board 5 shown in FIG. It is a manufacturing process diagram to be described. First,
As shown in FIG. 4A, copper layers 12a are formed on both surfaces of the second printed wiring board 5.

Next, as shown in FIG. 4 (b), a plurality of circular holes 13 are linearly formed on both sides of the printed wiring board 5, a circular hole 14 is provided at the center thereof, and a plurality of circular holes 13 are provided. hand,
Long holes 15 are formed near the center of the circular hole 14 by drilling or the like.

Next, as shown in FIG.
A conductor 16 is formed on the inner walls of the holes 3 and 14 and the elongated hole 15 and on the copper layer 12a by an electroless copper plating method or an electrolytic copper plating method. Next, the copper layer 12a other than the predetermined layer is etched by using a photosensitive mask to form the ground patterns 7, 8 and the signal lines 6 as shown in FIG. At this time, the ground pattern 7 has a plurality of circular holes 13 on one side.
And the ground pattern 8 is formed so as to include the plurality of circular holes 13 and the elongated holes 15 on the other side, and the signal line 6 includes the central circular hole 14.
It is formed along the ground patterns 7 and 8.

Next, as shown in FIG. 4 (e), of the plurality of circular holes 13 on both sides of the printed wiring board 5, the center of the circular hole 13 at the end, a part of the elongated hole 15, and the center. The end of the printed wiring board 5 is cut along the dotted line shown in FIG. 4E so as to pass through the center of the circular hole 14 of the portion, and a groove is formed at the end of the printed wiring board 5. This cutting is performed by using a die or a router. In this way, as shown in FIG. 4F, the signal electrode 11 is formed by the conductive layer left in the circular hole 14 at the center, and the conductive electrode in the circular hole 13 left at the extreme ends of the circular holes 13 on both sides. A ground electrode 17 is formed by the layers, and ground patterns 7 and 8 are further formed.
The end face conductor layer 18 is formed by the conductive layer left in the long hole 15 on the signal electrode 11 side of the first embodiment.

As shown in FIG. 5, the ground patterns 7 and 8 may be formed with protrusions extending parallel to the printed wiring board 5, and may be formed to extend to these protrusions.
At this time, the area of the printed wiring board 5 can be reduced, and high-density mounting and miniaturization are possible. In this case, a ground electrode 17 may be formed on the opposite side of the signal electrode 11 at the projecting portions of the ground patterns 7 and 8 as shown in FIG. At this time, when the printed wiring board 5 is soldered to another board, the ground electrode pad on the other board is formed inside the protruding portion forming the ground electrode 17 of the printed wiring board 5, so that the solder The attachment area can be reduced. Also, it goes without saying that the configuration shown in FIG. 7 may be combined with the configuration shown in FIG. 5 and FIG. Further, the signal line 6 may be formed on the inner layer of the printed wiring board 5 as shown in FIG. 8, and the ground electrodes on both sides of the signal electrode 11 may be connected.

[0017]

As described above, according to the present invention, the signal line on the printed wiring board constitutes a microstrip line, and a plurality of ground electrodes are provided on both sides near the signal electrode in the thickness direction of the printed wiring board. Since the signal electrode is configured to sandwich the signal electrode, the structure of the signal electrode is a pseudo coaxial line structure, so that there is little change in characteristic impedance at the signal electrode portion, and signal reflection and loss are reduced. It has the effect of being able to do so.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a high-frequency printed wiring board according to the present invention.

FIG. 2 is a schematic perspective view of a high-frequency printed wiring board according to the present invention.

FIG. 3 is a schematic perspective view of a high-frequency printed wiring board according to the present invention.

FIG. 4 is a manufacturing process diagram for explaining a manufacturing method for manufacturing a high-frequency printed wiring board according to the present invention.

FIG. 5 is a plan view of a printed wiring board of the high-frequency printed wiring board according to the present invention.

FIG. 6 is a plan view of a printed wiring board of the high-frequency printed wiring board according to the present invention.

FIG. 7 is a plan view of a printed wiring board of the high-frequency printed wiring board according to the present invention.

FIG. 8 is a schematic perspective view of a high-frequency printed wiring board according to the present invention.

FIG. 9 is a cross-sectional view of a conventional printed wiring board.

FIG. 10 is a cross-sectional view of a conventional printed wiring board.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st printed wiring board, 2 ... signal line, 3, 4 ...
Ground pattern, 5: second printed wiring board, 6: signal line, 7, 8: ground pattern, 9: notch, 1
DESCRIPTION OF SYMBOLS 1 ... Signal electrode, 12 ... Through hole, 13, 14 ... Circular hole, 15 ... Elongated hole, 16 ... Conductor, 17 ... Ground electrode,
18 ... End face 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 F term (Reference) 5E317 AA22 AA24 AA25 BB01 BB11 CC15 GG16 5E338 AA03 BB02 BB13 BB25 BB65 CC02 CC04 CC06 CD01 CD23 CD32 EE13 5E344 AA01 AA22 BB02 BB06 BB15 CC05 CC13 CC23 CD09 DD02 EE08 5E346 AA42 BB02 BB11 FF42 HH06

Claims (5)

[Claims] A first printed wiring board; a second printed wiring board mounted on the first printed wiring board;
A first signal line formed on the first printed wiring board to constitute a microstrip line;
A second signal line formed on the other side of the printed wiring board opposite to the first signal line to form a microstrip line; and a second printed circuit board at an end of the second printed wiring board. Signal electrodes for electrically connecting the first and second signal lines continuously in the thickness direction, and on both sides of the first and second signal lines, respectively, so as to sandwich the signal electrode; Forming through holes in the first and second ground patterns formed on the first and second printed wiring boards and the second printed board inside the first and second ground patterns; And a ground electrode for electrically connecting the first and second ground patterns, respectively. 2. A first printed wiring board, a second printed wiring board mounted on the first printed wiring board and having a notch formed at an end, and extending inside the notch. A first signal line formed on the first printed wiring board to form a microstrip line; and a microstrip formed on the second printed wiring board on the side opposite to the first signal line. A second signal line that forms a line and an electrical connection between the first and second signal lines in the thickness direction of the second printed wiring board at an end of the concave portion of the second printed circuit board. And a signal electrode connected to the first and second signal lines, respectively, formed on the first and second printed wiring boards so as to sandwich the signal electrode in the vicinity of the concave portion on both sides of the first and second signal lines, respectively. First and second 2 ground pattern and the second ground pattern inside the first and second ground patterns.
And a ground electrode for electrically connecting the first and second ground patterns, respectively, to the printed wiring board. 3. The high-frequency printed wiring board according to claim 2, wherein a conductive layer is formed inside or outside the second ground pattern in the recess. 4. The high-frequency printed wiring board according to claim 1, wherein said through-hole is an elongated through-hole. 5. A step of forming copper layers on both sides of a printed wiring board, and arranging a plurality of first through holes in a straight line on both sides of the printed wiring board; Forming a through hole; forming a facing ground pattern including the first through hole and a signal line including the second through hole by etching; and forming the first and second through holes. Forming a conductive layer on the inner wall of the printed wiring board, forming a recess in the printed wiring board through the through hole at the end of the printed wiring board of the first through hole and the second through hole, Mounting the printed wiring board on another printed wiring board.