JP3641710B2 - Method of connecting circuit function blocks using conversion line of high-frequency transmission line, high-frequency circuit board using the same, and mounting structure thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a circuit functional block connection method using a conversion line of a high-frequency transmission line, a high-frequency circuit board using the same, and a mounting structure thereof.
[0002]
[Prior art]
In wireless communication, since the amount of information to be transmitted can be increased as the frequency of electromagnetic waves used increases, research in high-frequency regions such as microwaves, quasi-millimeter waves, and millimeter waves is actively conducted. On the other hand, the higher the frequency, the shorter the wavelength of the electromagnetic wave, so that higher physical dimensional accuracy is required in the configuration of the device (circuit) that handles it, and the mounting method and measurement technique become difficult.
[0003]
Conventionally, the most commonly used high-frequency circuit board mounting structure is, as shown in FIG. 7, a high-frequency semiconductor device 1 and a ceramic substrate 2 each formed as a functional block, for example, a pedestal formed of Kovar. 3 is fixed by an Au-Sn eutectic solder 5, and the high-frequency semiconductor device 1 and the ceramic substrate 2 are connected by a wire 4 such as Au.
[0004]
As shown in FIG. 8, the connection portion includes an input / output pad 10 of the high-frequency semiconductor device 1 designed with a coplanar line, a microstrip line 14 of the ceramic substrate 2, a GND pad 11 of the high-frequency semiconductor device 1, and a ceramic substrate. Two GND patterns 12 are connected by Au wires 4 respectively. The GND pad 12 is connected to a GND layer (not shown) formed on the back surface through the through hole 13.
[0005]
Each functional block constituted by the high-frequency semiconductor device 1 and the ceramic substrate 2 has one function such as a passive element block such as BPF and BEF constituted by a pattern as well as a transmission line, and an impedance matching circuit block. Consists of blocks with.
[0006]
As shown in FIG. 7, when configured as a high-frequency circuit module, generally, the mounting surface of the pedestal 3 is subjected to a difference between the thickness of the high-frequency semiconductor device 1 and the thickness of the ceramic substrate 2 by a processing method such as etching. Corresponding steps are formed, the height of the connection surface between the high-frequency semiconductor device 1 and the ceramic substrate 2 after mounting is made uniform, and the length of the Au wire 4 for connection is made as short as possible to reduce the deterioration of the high-frequency characteristics. I have to. Further, in order to shorten the length of the Au wire 4, it is necessary to make the distance between the high-frequency semiconductor device 1 and the ceramic substrate 2 as small as possible, and the processing accuracy of the base 3 and the positional accuracy at the time of mounting are required. Yes.
[0007]
Further, as disclosed in “Basics of Microwave Circuits and Their Applications” P221, FIG. 4.97 (Yoshihiro Konishi, 1992, General Electronic Publishing Co., Ltd.), coplanar lines and microstrip lines are converted on a substrate. It has been proposed to use a conversion substrate.
[0008]
As shown in FIGS. 9 and 10, the conversion substrate is formed on a ceramic substrate 2 serving as a conversion substrate, with a center conductor 18 having a line width Wc and a GND pattern formed on both sides thereof with a predetermined width G therebetween. A coplanar line composed of 19, a microstrip line 14 having a line width Wm, and a trapezoidal conductor connecting the central conductor 18 and the microstrip line 14 are formed.
[0009]
Note that the end of the GND pattern 19 on the microstrip line 14 side has a wider spread angle than the spread angle of the trapezoidal conductor. The GND pattern 19 is connected to the GND pattern 15 formed on the entire back surface of the ceramic substrate 2 through the through hole 13.
[0010]
Therefore, instead of the ceramic substrate 2 of FIG. 8, the conversion substrate of FIGS. 9 and 10 can be used.
[0011]
In FIG. 10, when the coplanar line and the microstrip line 14 are arranged on the same substrate, the characteristic impedance of the microstrip line 14 is determined by the line width Wm, the thickness H of the ceramic substrate 2, and the dielectric constant ε. If the thickness H and the dielectric constant ε of the ceramic substrate 2 are determined, the line width Wm of the microstrip line 2 is uniquely determined.
[0012]
On the other hand, since the characteristic impedance of the central conductor 18 of the coplanar line is determined by Wc / (Wc + 2 × G) and the dielectric constant ε, the characteristic impedance basically depends on the design conditions of the surface of the ceramic substrate 2. If the thickness H exceeds a certain level, it does not depend on the thickness H of the ceramic substrate 2. However, since the existence of unnecessary mode spurs such as a microstrip line is basically known in the coplanar line, the thickness H of the ceramic substrate 2 is generally several times or more than (Wc + 2 × G). Set to
[0013]
From the above, when the coplanar line and the microstrip line exist on the same thickness substrate, the design is usually made in the relationship of Wc <Wm. Further, there is a so-called conversion chip in which the conversion portion of FIG. 10 is formed into a chip shape, which is used when a microstrip line is measured with a coplanar probe or when a coplanar line is measured using a connector. In that case, the chip and the substrate are connected by an Au wire.
[0014]
In a high-frequency circuit, when a module is created by mounting a plurality of functional blocks at the same time and the characteristics of the module are measured, the characteristics of each functional block cannot be confirmed, so a specific functional block includes an adjustment circuit. It becomes difficult to deal with cases and defects. For this reason, a dedicated measuring jig is created for each functional block, its characteristics are measured for each functional block before mounting, and then assembled as a module. At this time, the conversion chip is often used.
[0015]
Further, in measuring the characteristics, it is necessary to consider that the ceramic substrate 2 is mechanically fixed securely and an electrically stable connection is obtained so that there is no error in the measurement result.
[0016]
[Problems to be solved by the invention]
When configuring a high-frequency circuit module with multiple functional blocks, the characteristics of each functional block are measured and mounted on the pedestal, which requires not only strict precision in processing and mounting accuracy of the pedestal, but also in proportion to the number of mounting points. Large implementation costs.
[0017]
In addition, in measuring each functional block, an expensive jig must be used to eliminate variations and errors in the measurement results, and the actual use such as connecting with a temporary wire or using a conversion chip for measurement. Measurement is performed in a state different from the shape, and improvement in measurement accuracy cannot be expected. For this reason, the reproducibility of the characteristic of the functional block after incorporating it as a module falls.
[0018]
Furthermore, the work such as attachment / detachment of temporary wiring for measurement and wiring as a module is troublesome twice, and the work cost and material cost are greatly increased.
[0019]
In view of the above circumstances, the object of the present invention is to make it possible to measure the characteristics of each functional block individually after assembling a plurality of functional blocks on a single board and assembling them into a pedestal, eliminating the need for expensive measurement jigs Circuit function block connection method using a high-frequency transmission line conversion line, which can reduce the mounting cost, work cost, material cost, eliminate measurement variations, and improve the reproducibility of characteristics to provide a mounting structure of a high-frequency circuit board and the high-frequency circuit board using the same.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 of the present application provides a high-frequency transmission line conversion line for converting a coplanar line and a microstrip line for connecting a plurality of circuit functional blocks. A GND pattern is formed on the entire back surface, and the surface of the substrate is connected by a central conductor of a coplanar line having a central conductor blocked by a slit and a trapezoidal conductor whose width gradually increases from the central conductor. A center conductor of the microstrip line and an opening having a spread angle larger than the spread angle of the trapezoidal conductor, connected to the GND pattern on the back surface through a through hole, and on both sides of the center conductor of the coplanar line The formed GND pattern is formed, and a plurality of circuit function blocks are assembled on a pedestal and provided on the central conductor of the coplanar line. By applying a high-frequency coplanar probe before and after the slit to block the planar line after the measurement of the characteristics of the circuit function blocks, and to connect the center conductor of the blocked coplanar line with the slit in the conductor for connection.
[0021]
According to the second aspect of the present invention, the GND pattern is formed on the entire back surface of the substrate, the conversion line of the high-frequency transmission line for converting the coplanar line and the microstrip line for connecting a plurality of circuit functional blocks, On the surface of the substrate, a central conductor of a coplanar line provided with a central conductor cut off by a slit, and a trapezoidal conductor whose width gradually spreads from the central conductor to both sides in the input / output direction of the central conductor of the coplanar line And a central conductor of the coplanar line that is connected to the GND pattern on the back surface through a through hole, and has a central conductor of the microstrip line connected by And a GND pattern formed on both sides of the circuit board, and a plurality of circuit function blocks are assembled on a pedestal. After measuring the characteristics of the circuit functional block by applying a high-frequency coplanar probe before and after the slit that cuts off the coplanar line provided in the core conductor, connect the central conductor of the coplanar line blocked by the slit with a connecting conductor I tried to do it.
[0022]
According to a third aspect of the present invention, there is provided a high frequency circuit board configured by mounting a plurality of circuit function blocks on a substrate and connecting input / output portions of the function blocks with a conductor. The input / output unit is connected by the connection method according to claim 1 or claim 2.
[0023]
Furthermore, the invention described in claim 4 is a mounting structure of a high frequency circuit board in which a plurality of circuit functional blocks are mounted on a board and the input / output portions of each functional block are connected by a conductor to constitute the high frequency circuit board. Thus, at least one of the plurality of circuit function blocks is configured by a high-frequency semiconductor device, and an input / output unit of the circuit function block configured by another circuit function block and the high-frequency semiconductor device is the claim 1 or claim. The connection method described in Item 2, and the other circuit function block and the circuit function block configured by the high-frequency semiconductor device are connected by a bump.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 5 show a first embodiment of the present invention. FIG. 1 is an enlarged cross-sectional view showing a main part of a mounting structure according to the present invention. FIG. 2 is a diagram of a high-frequency transmission line in FIG. FIG. 3 is a front view showing a mounting state according to the present invention, and FIGS. 4 and 5 are front views showing measurement states of each functional block.
[0025]
In the figure, the same components as those in FIGS. 7 to 10 are denoted by the same reference numerals. A trapezoidal conductor 32 connects the microstrip line 14 and the central conductor 18 of the coplanar line. A slit 31 is formed on the central conductor 18 of the coplanar line.
[0026]
A bump 20 is formed on each input / output pad of the high-frequency semiconductor device 1, aligned with each predetermined connection position of the substrate, and connected by being heated and pressurized. In the figure, the input / output pad 10 of the high-frequency semiconductor device 1 is connected to the central conductor 18 of the coplanar line, and the GND pad 11 and the GDN pattern 19 of the high-frequency semiconductor device 1 are connected. Moreover, although the bump height after mounting is about several tens of μm per piece, bumps may be formed in multiple stages as required. Reference numeral 16 denotes a connection conductor, which connects GND patterns 19 formed on both sides of the center conductor 18.
[0027]
With such a configuration, as shown in FIG. 3, the ceramic substrate 2 is mounted on the pedestal 3 via the Au—Su eutectic solder 5, and the high-frequency semiconductor device 1 is further mounted on the ceramic substrate 2 via the bumps 20. Is implemented. At this time, the Au wire 4 shown in FIG. 2 is not connected, and the central conductor 18 of the coplanar line is cut by the slit 31.
[0028]
Therefore, the characteristics of the high-frequency semiconductor device 1 as one circuit functional block are measured by applying a high-frequency coplanar probe 40 to the connecting conductor 16 side of the central conductor 18 cut by the slit 31 as shown in FIG. can do.
[0029]
In addition, as shown in FIG. 5, a high-frequency coplanar probe 40 is applied to the microstrip line 14 side of the central conductor 18 cut by the slit 31 to measure the characteristics of the ceramic substrate 2 as a circuit functional block. it can.
[0030]
After each circuit function block is measured (adjusted in some cases), as shown in FIG. 2, the central conductor 18 cut by the slit 31 is connected by the Au wire 4 (two wires in FIG. 2).
[0031]
Regarding the connection between the high-frequency semiconductor device 1 and the ceramic substrate 2, the above-described bump connection configuration has much less loss than the conventional wire connection of FIGS. 7 and 8, and the wire connection distance is the conventional length. In contrast, in the above configuration, the width of the slit 31 formed in the central conductor 18 of the coplanar line can be greatly shortened, so that the deterioration of characteristics can be extremely reduced.
[0032]
That is, the length of the Au wire 4 used for the connection is required to be about 600 to 800 μm at the minimum in the conventional connection length, whereas in the above configuration of the present invention, the width of the slit 31 is several tens to several hundred μm even if it is long. Since it can be significantly shortened (about G to Wc in FIG. 2), deterioration in characteristics due to the wire can be suppressed to a small level.
[0033]
Further, since the ceramic substrate 2 does not need to be divided and formed as in the prior art, the high-frequency semiconductor device 1 can be connected to the ceramic substrate 2 via the bumps 20. The number of parts to be reduced can be reduced, and the accuracy of the mounting position can be relaxed. Moreover, it becomes unnecessary to provide a level | step difference in the surface of the base 3, and the process of the base 3 becomes easy.
[0034]
FIG. 6 shows a second embodiment of the present invention and is a plan view showing a structure of a conversion line of a high-frequency transmission line.
In the figure, the same components as those in FIG. 2 are denoted by the same reference numerals.
[0035]
This embodiment is for measuring characteristics of each circuit functional block using a high-frequency coplanar probe in a high-frequency circuit board on which a plurality of circuit functional blocks are mounted. The length of the central conductor 18 of the coplanar line is as follows. It is sufficient that the length allows the high-frequency coplanar probe to be brought into contact with the measurement.
[0036]
A coplanar line is inserted between the microstrip lines 14, and a slit 31 is formed in the central conductor 18 of the coplanar line. For this reason, transmission loss occurs in microstrip / coplanar conversion, slit-to-slit connection, and coplanar / microstrip conversion, but each loss is very small, and each functional block divided as before is connected with wires. Compared to this, there is no practical problem because the wire length can be shortened.
[0037]
In each of the above embodiments, only one through hole 13 for connecting the GND pattern on the back surface of the ceramic substrate 2 and the GND pattern 19 on the front surface is shown, but it is necessary that the number of through holes 13 is one. However, a plurality of them can be provided as necessary. In particular, in a coplanar line, an appearance of an unnecessary spurious response such as a microstrip line or a slot line differs depending on the number and position of the through holes 13, and it is preferable to confirm and set in advance.
[0038]
Furthermore, the conductor connecting the central conductor 18 cut by the slit 31 is not limited to the Au wire, and an Au ribbon or the like may be used.
[0039]
The connection conductor 16 is provided for the purpose of minimizing the disturbance of characteristic impedance due to the edge effect at the end of the center conductor 18 of the coplanar line. The gap between the end of the center conductor 18 and the center conductor 18 The gap G of the GND pattern 19 formed on both sides thereof is the same. Although the width of the connection conductor 16 is not specified, it is desirable that the connection conductor 16 be as thick as possible. Further, when there is a restriction on the pattern layout, the connection conductor 16 may not be provided.
[0040]
【The invention's effect】
As described above, according to the present invention, a plurality of circuit functional blocks including a high-frequency semiconductor device are formed by forming a coplanar line in a microstrip line that transmits a high-frequency signal and forming a slit in the central conductor of the coplanar line. Is mounted on a single high-frequency circuit board, its characteristics are measured for each circuit functional block, and after adjustment is made in some cases, the slit portion of the central conductor of the coplanar line is connected with a connecting conductor such as an Au wire. As a result, the number of components constituting the high-frequency circuit module can be reduced, and at the same time, it is not necessary to mount a plurality of circuit function block substrates with high accuracy as in the prior art.
[0041]
In addition, since the characteristics of each circuit functional block can be measured after being mounted on a high-frequency circuit board, not only jigs for measuring the characteristics for each circuit functional block can be eliminated, but also the measurement. Therefore, the cost of the mounting work can be greatly reduced.
[0042]
In addition, since it is possible to measure the characteristics of each circuit functional block after mounting on a high-frequency circuit board, the variation in measurement results is reduced compared to the case of mounting after measuring each circuit functional block individually. The reliability of the circuit board can be improved.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view showing a main part of a mounting structure according to the present invention.
2 is a plan view showing the structure of a conversion line of the high-frequency transmission line in FIG. 1. FIG.
FIG. 3 is a front view showing a mounting state according to the present invention.
FIG. 4 is a front view showing a measurement state of each functional block.
FIG. 5 is a front view showing a measurement state of each functional block.
FIG. 6 is an enlarged plan view showing a structure of a conversion line of a high-frequency transmission line according to another embodiment.
FIG. 7 is a front view showing a mounting form on a conventional high-frequency circuit board.
8 is an enlarged plan view showing a connection state between the high-frequency semiconductor device and the microstrip line in FIG. 7;
FIG. 9 is a perspective view of a conventional coplanar / microstrip conversion line substrate.
10 is an enlarged plan view of FIG. 9;
[Explanation of symbols]
3 ... pedestal, 4 ... conductor, 14 ... microstrip line,
15 ... GND pattern, 18 ... center conductor, 19 ... GND pattern,
31 ... slit, 32 ... conductor, 40 ... high frequency coplanar probe.

Claims (4)

A conversion line of a high-frequency transmission line for converting a coplanar line and a microstrip line for connecting a plurality of circuit function blocks is formed on the entire back surface of the substrate with a GND pattern cut off by a slit on the surface of the substrate. A central conductor of a coplanar line having a central conductor formed therein, a central conductor of a microstrip line connected by a trapezoidal conductor whose width gradually increases from the central conductor, and a spread larger than the spread angle of the trapezoidal conductor A structure having a corner opening, connected to the GND pattern on the back surface through a through hole, and formed on both sides of the central conductor of the coplanar line;
After assembling a plurality of circuit function blocks on the pedestal, measuring the characteristics of the circuit function blocks by applying a high-frequency coplanar probe before and after the slit for blocking the coplanar line provided on the central conductor of the coplanar line, and then blocking with the slit A circuit functional block connection method using a conversion line of a high-frequency transmission line, wherein a center conductor of a coplanar line is connected by a connection conductor. A GND pattern is formed on the entire back surface of the substrate, and a high-frequency transmission line conversion line for converting a coplanar line and a microstrip line for connecting a plurality of circuit functional blocks is cut off by a slit on the surface of the substrate. A central conductor of a microstrip line connected by a trapezoidal conductor whose width gradually increases from the central conductor on both sides in the input / output direction of the central conductor of the coplanar line with the central conductor An opening having a spread angle larger than the spread angle of the trapezoidal conductor, connected to the GND pattern on the back surface through a through hole, and formed on both sides of the central conductor of the coplanar line And the configuration
After assembling a plurality of circuit function blocks on the pedestal, measuring the characteristics of the circuit function blocks by applying a high-frequency coplanar probe before and after the slit for blocking the coplanar line provided on the central conductor of the coplanar line, and then blocking with the slit A circuit functional block connection method using a conversion line of a high-frequency transmission line, wherein a center conductor of a coplanar line is connected by a connection conductor. In a high-frequency circuit board configured by mounting a plurality of circuit function blocks on a board and connecting the input / output parts of each function block with a conductor,
The high-frequency circuit board according to claim 1, wherein input / output portions of the respective circuit functional blocks are connected by the connection method according to claim 1. A mounting structure of a high-frequency circuit board, in which a plurality of circuit functional blocks are mounted on a board, and the input / output parts of each functional block are connected by a conductor to constitute a high-frequency circuit board,
3. At least one of the plurality of circuit function blocks is configured by a high frequency semiconductor device, and an input / output unit of a circuit function block configured by another circuit function block and the high frequency semiconductor device is the claim 1 or 2. A mounting structure for a high-frequency circuit board, wherein the other circuit function block and the circuit function block configured by the high-frequency semiconductor device are connected by a bump.

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