JP3704440B2 - High frequency wiring board connection structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency wiring board on which high-frequency elements in a microwave band to a millimeter-wave band are mounted, and particularly to a high-frequency circuit that can transmit signals between high-frequency elements without deteriorating the characteristics of high-frequency signals. The present invention relates to a wiring board connection structure.
[0002]
[Prior art]
Conventionally, in a high-frequency package equipped with a high-frequency circuit element that handles microwaves and millimeter waves, hermetic sealing is performed in a cavity formed by a dielectric substrate and a wall or lid connected to the surface of the dielectric substrate. The signal transmission line electrically connected to the high frequency element and the signal transmission line formed on the external circuit board are electrically connected to input and output the high frequency signal. Yes.
[0003]
Therefore, conventionally, in a high frequency module which is an application example of this type of high frequency wiring board, as shown in FIG. 9A, a cavity formed by a dielectric substrate 41 made of a dielectric and lids 42 and 42 '. High frequency elements 44 and 44 ′ are mounted in 43 and 43 ′, respectively, and hermetically sealed. For high-frequency signal input / output, high-frequency transmission lines 45 and 45 ′ such as strip lines connected to the high-frequency elements 44 and 44 ′ are formed on the surface of the dielectric substrate 41. The transmission lines 45 and 45 'are connected to each other by wire bonding or a ribbon through a conductor layer 47 insulated by an insulator 46 formed on the lids 42 and 42'.
[0004]
Further, as shown in FIG. 9B, a signal transmission line 49 is formed inside the dielectric substrate 41, and the signal transmission line 49 and the transmission lines 45 and 45 ′ are connected through the through-hole conductor 50. A semiconductor package has been proposed. Furthermore, as shown in FIG. 9C, a plurality of high frequency elements are electromagnetically sealed with a conductive lid independently of each other, and at the input / output ends of each high frequency element, a dielectric substrate is respectively provided. A through hole penetrating from the main surface to the back surface of the metal plate 51 is formed, coaxial transmission lines 52 and 53 are arranged inside the through hole, and input / output ends on the main surface side of the coaxial transmission lines 52 and 53 The coaxial transmission lines 52 and 53 connected to the input end of the circuit block via the coaxial transmission line connection portions 54 and 54 ′ that electrically connect the input and output ends of the circuit block, and the output ends of other circuit blocks Japanese Patent Laid-Open No. 7-263887 proposes a configuration in which the coaxial transmission lines 52 ′ and 53 ′ are connected to each other and further connected via a connection member 55 on the back surface side.
[0005]
Such a high-frequency module is required to be able to input and output signals between high-frequency elements without degrading the transmission characteristics of high-frequency signals, and to be easy to manufacture.
[0006]
[Problems to be solved by the invention]
However, in FIG. 9A, when a high-frequency signal passes through the conductor layer 47 and passes through the wall bodies 42 and 42 ', the signal transmission line is converted from the microstrip line to the strip line at the wall body passing portion. Therefore, it is necessary to narrow the signal transmission line width in order to achieve impedance matching. As a result, there is a problem that reflection characteristics and radiation losses are likely to occur at the passing portion, and the transmission characteristics of high-frequency signals are deteriorated. In addition, in order to draw out the signal transmission lines 45 and 45 ′ to the outside of the cavities 42 and 42 ′, it is necessary to form at least the line passing portion of the wall body with a dielectric, which makes the structure complicated and reduces the cost of the entire module. It was also a factor to raise.
[0007]
On the other hand, FIG. 9B does not pass through the wall body by the through-hole conductor 50, so that the signal characteristic degradation is small. However, when the use frequency of the signal to be transmitted exceeds 40 GHz, the signal transmission line 49 and the through-hole conductor 50 Since the connection portion with the hole conductor 50 is bent, the transmission loss at the bent portion is rapidly increased, and it is difficult to transmit a high-frequency signal.
[0008]
Also in FIG. 9C, although the transmission loss of the high frequency signal can be reduced by the coaxial transmission lines 54 and 54 ′ inside the through-hole conductors 52 and 52 ′, the coaxial transmission line is provided in the through hole. There is a problem that it is difficult to form, and the reliability of the connection portion is inferior.
[0009]
Therefore, the present invention electromagnetically seals the high-frequency element formed on the surface of the dielectric substrate, has a small transmission loss during signal transmission between the high-frequency elements, and is small and highly reliable. An object of the present invention is to provide a high-frequency wiring board.
[0010]
[Means for Solving the Problems]
As a result of repeated studies on a structure capable of reducing loss and miniaturization in the connection structure of a high-frequency wiring board, the present inventors have formed one end portion on the surface of the dielectric substrate in the cavity by the lid. Is connected between the high-frequency elements by connecting the first high-frequency transmission line electrically connected to the high-frequency elements by electromagnetic coupling with a second high-frequency transmission line formed in a region outside the cavity. It has been found that electrical connection can be made without degrading characteristics, and that a simple and miniaturized wiring board can be connected.
[0011]
That is, the connection structure of the high frequency wiring board of the present invention is formed on the first dielectric substrate and the high frequency device mounted on the first dielectric substrate surface and the surface of said first dielectric substrate, whereas of a high frequency wiring board whose ends comprises a first high frequency transmission line path that is connected to the high frequency device and electrically, is ground layer surface or the slot hole is provided is formed, the interior or back surface it comprises a second dielectric substrate second high frequency transmission line path is formed, together with the second dielectric substrate is made of a material having a low dielectric constant than the first dielectric substrate, wherein said first high frequency transmission line at high frequency wiring board, wherein a second dielectric said in the substrate second high frequency transmission line, electromagnetically through the slot hole formed in the ground layer Specially connected It is an.
[0012]
Another connection structure of a high frequency wiring board of the present invention is formed on the first dielectric substrate and the first dielectric mounted on the substrate surface a high frequency device and the first surface of the dielectric substrate , a high frequency one end comprises said formed on the back surface of the first high-frequency transmission line and said first dielectric substrate that is the high frequency element and electrically connected, and a ground layer in which the slot hole is provided Comprising a wiring substrate and a second dielectric substrate having a second high-frequency transmission line formed therein or on the back surface;
Together consist of a low dielectric constant material than the second dielectric substrate is the first dielectric substrate, said first high-frequency transmission line in the high frequency wiring board, said in the second dielectric substrate a second high frequency transmission line, is characterized in that formed by electromagnetically connected via the slot hole formed in the ground layer.
[0013]
In addition, the first high-frequency transmission line is composed of one selected from a microstrip line, a coplanar line, and a coplanar line with a ground, and the second high-frequency transmission line is a microstrip line, a coplanar line, and a coplanar with a ground. It is desirable to be comprised from 1 type chosen from a track | line and a triplate track | line.
[0014]
[Action]
According to the above configuration of the present invention, in particular, the other end of the first high-frequency transmission line and the end of the second high-frequency transmission line are electromagnetically connected through, for example, a slot hole formed in the ground layer. The transmission line does not pass through the dielectric wall or through the through-hole conductor or the coaxial line, so that the high-frequency signal is generated when passing through the wall or the bent portion. The generation of reflection loss and radiation loss can be suppressed as much as possible, and it is not necessary to form a coaxial line or the like, and it is possible to connect a wiring board that can be reduced in size with low transmission loss.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a schematic cross-sectional view of the first embodiment of a high-frequency module that is an application example of a high-frequency wiring board connection structure according to the present invention.
According to the high-frequency module 1 of FIG. 1, two or more lids 3 and 3 ′ are joined to the surface of a dielectric substrate 2 made of a dielectric material, and the dielectric substrate 2 and the lids thereof. Cavities 4, 4 'are formed by 3, 3'. High-frequency elements 5 and 5 ′ for high frequency such as MMIC and MIC are mounted on the surface of the dielectric substrate 2 in the cavities 4 and 4 ′, respectively. Further, in the cavities 4 and 4 ′ of the module, a line for transmitting a signal to the high-frequency elements 5 and 5 ′ is selected from one selected from a microstrip line, a strip line, and a grounded coplanar line. First high-frequency transmission lines (hereinafter abbreviated as first lines) 6 and 6 ′ are formed on the surface of the dielectric substrate 2 in the cavities 4 and 4 ′ to electrically connect the high-frequency elements 5 and 5 ′. It is connected to the.
[0016]
The dielectric substrate 2 is made of ceramics such as alumina, mullite, silicon nitride, silicon carbide, and aluminum nitride having a dielectric constant of 20 or less, glass ceramics, ceramic metal composite materials, glass organic resin composite materials, and dielectric materials such as quartz. It is desirable to consist of.
[0017]
The lids 3 and 3 ′ are made of an electromagnetic shielding material that can prevent electromagnetic waves from the cavities 4 and 4 ′ from leaking to the outside or electromagnetic waves from leaking to the outside. For example, metal, conductive ceramics A ceramic metal composite material or the like can be used, but a conductive material may be applied to the surface of the insulating substrate, but from the viewpoint of cost, a metal is preferable.
[0018]
The first lines 6, 6 ′ are preferably made of a low resistance conductor such as Ag, Cu, Au, etc. From this point, the dielectric substrate 2 is best made of glass ceramics having a firing temperature of about 800 to 1000 ° C. Yes, this combination enables simultaneous firing of the dielectric substrate 2 and the signal transmission line.
[0019]
The high-frequency elements 5 and 5 ′ can be connected with small transmission loss by mounting the flip chip directly on the first lines 6 and 6 ′, but the present invention is not limited to this, for example, It can also be connected by a gold ribbon, a plurality of wire bondings, or a conductor plate in which a conductor such as Cu is formed on a substrate such as polyimide.
[0020]
According to the present invention, as shown in FIG. 1, a ground layer 8 is formed almost entirely on the surface of a second dielectric substrate (hereinafter abbreviated as second substrate) 13 which is another member and made of a dielectric material. In the ground layer 8, slot holes 9 and 9 ′ are formed.
[0021]
According to FIG. 1, a second high-frequency transmission line (hereinafter abbreviated as a second line) 7 made of one selected from a microstrip line, a strip line, a grounded coplanar line, and a triplate is a second. It is formed inside the substrate 13.
[0022]
Then, as shown in FIG. 1, the other end of the first line 6 electrically connected to the high-frequency element 5 and one end of the second line 7 formed inside the second substrate 13 are shown in FIG. The first line 6 and the second line 13 are bonded to each other so as to face each other through the slot hole 9, thereby electromagnetically coupling the first line 6 and the second line 7. Thus, a signal with a small loss is transmitted.
[0023]
Similarly, the other end portion of the first line 6 ′, one end of which is electrically connected to the high-frequency element 5 ′, and one end of the second line 7 formed inside the second substrate 13 are shown in FIG. As described above, the first line 6 and 6 ′ and the second line 7 can be electromagnetically coupled by forming the positions so as to face each other via the slot hole 9 ′. A signal with a small loss is transmitted between the first line 6 ′ and the second line 7.
[0024]
As a result, the high frequency element 5 and the high frequency element 5 ′ can be connected with low loss via the first line 6, the second line 7, and the first line 6 ′.
[0025]
The specific structure of the electromagnetic coupling will be described. The first line 6 and the second line 7 have an end of each line 1/1 of a transmission signal having a necessary frequency from a position immediately above the center of the slot hole 9. It is desirable that the slot hole 9 is formed in a position opposite to the length corresponding to the four wavelengths, and the shape of the slot hole 9 is a rectangular hole having a long side and a short side. It is set as appropriate according to the bandwidth. In particular, it is desirable that the long side of the slot hole 9 has a length corresponding to ½ wavelength of the signal frequency, and the short side of the slot hole 9 is set to a length corresponding to 1/5 wavelength to 1/50 wavelength. It is desirable. The first line 6 ′ and the second line 7 are also arranged in the same manner.
[0026]
In addition, the first substrate 2 and the second substrate 13 can be bonded and fixed by an adhesive or screwing, and there is no problem if they are simply overlapped without using an adhesive.
[0027]
Although FIG. 1 shows the case where the ground layer 8 is formed on the surface of the second substrate 13, the configuration of the present invention is not limited to this, and the ground layer 8 is not limited to the second substrate 13. 13, and in this case, the second line 7 is formed inside or on the back surface of the second substrate 13.
[0028]
Further, as shown in FIG. 1, a ground layer 10 is formed at the junction between the first substrate 2 and the electromagnetic wave shielding lids 3 and 3 ′, and is electrically connected to the ground layer 8 through the via holes 11. Since the electromagnetic waves in the cavities 4 and 4 'can be shielded, the electromagnetic waves generated in the high-frequency elements 5, 5' and the first lines 6 and 6 'are prevented from leaking to the outside and adverse effects due to the external electromagnetic field. Since the operation can be prevented, the reliability of the wiring board can be improved. Furthermore, an electromagnetic wave absorber may be attached to the inner surfaces of the lids 3 and 3 ′ so that resonance from the signal transmission line does not affect other circuits and the like.
[0029]
Furthermore, a power supply line to the high frequency elements 5 and 5 ′ and a low frequency signal transmission line (not shown) through which a low frequency signal of 1 GHz or less is transmitted are formed on the surfaces of the cavities 4 and 4 ′ of the first substrate 2. In addition, other electronic components may be mounted, and these are led out of the cavities 4 and 4 ′ via via holes or through holes by a general multilayer wiring board technology, and further, high frequency To the outside of the module 1 for use.
[0030]
Furthermore, although the case where the ground layer 8 is formed on the second substrate 13 is shown in FIG. 1, the present invention is not limited to this, and the ground layer 8 is not necessarily limited to the second substrate 13. There is no need to be provided. A second embodiment in which the ground layer 8 is formed on the first substrate 2 is shown in FIG. FIG. 2 is an exploded cross-sectional view of the second embodiment.
[0031]
According to FIG. 2, in the high-frequency wiring board 14, the first substrate 2, the lids 3 and 3 ′, the cavities 4 and 4 ′, the high-frequency elements 5 and 5 ′, and the first lines 6 and 6 ′ are high-frequency. Although the configuration is the same as that of the wiring substrate 1, the ground layer 8 is formed almost entirely on the back surface of the first substrate 2 so as to be parallel to the first lines 6 and 6 '. Slot holes 9 and 9 'are formed in the ground layer 8, and a second line 7 made of one of a microstrip line, a strip line, a grounded coplanar line, and a triplate is formed as a dielectric. It is formed inside the second substrate 13 made of body material.
[0032]
The end portions of the first lines 6 and 6 ′ and the second line 7 formed inside the second substrate 13 are predetermined through the slot holes 9 and 9 ′ as described in FIG. By bonding the first substrate 2 and the second substrate 13 so as to be in a positional relationship, it is possible to electromagnetically couple the first lines 6 and 6 ′ and the second line 7, A signal with a small loss is transmitted.
[0033]
In addition, the 1st board | substrate 2 and the 2nd board | substrate 13 can be bonded together and fixed similarly to the high frequency wiring board 14 of FIG.
[0034]
In the high frequency module 14 of FIG. 2, the second line 7 is provided in the second substrate 13, but the second line is not necessarily provided in the second substrate 13. Therefore, FIG. 3 shows a third embodiment in which the second line 7 is formed on the back surface of the second substrate 13 which is another member. FIG. 2 is an exploded cross-sectional view of the second embodiment.
According to FIG. 3, in the high-frequency wiring board 15, the first substrate 2, the lids 3, 3 ′, the cavities 4, 4 ′, the high-frequency elements 5, 5 ′, the first lines 6, 6 ′, the slot. The holes 9, 9 ′ and the ground layer 8 have the same configuration as that of the high-frequency wiring board 1, but according to FIG. 2, the second line 7 is formed on the back surface of the second board 13.
[0035]
Then, the end portion of the first line 6 and the end portion of the second line 7 formed on the back surface of the second substrate 13 are in a predetermined positional relationship via the slot hole 9 as described in FIG. By bonding the first substrate 2 and the second substrate 13 so that the first line 6 and the second line 7 are bonded to each other, it is possible to electromagnetically couple the first line 6 and the second line 7, so that a signal with a small loss can be obtained. Transmission takes place.
[0036]
In addition, the 1st board | substrate 2 and the 2nd board | substrate 13 can be bonded together and fixed similarly to the high frequency modules 1 and 14 of FIG.1 and FIG.2.
[0037]
The second substrate 13 shown in FIGS. 1-3, the material of the first low dielectric constant than the substrate 2, to be particularly made of resin, is important in enhancing the electromagnetic coupling properties. The second substrate 13 may also have a heat sink, a housing, etc., and of course may be a member independent of this.
[0038]
In the present invention, the second line 7 is preferably electromagnetically shielded in the embodiment of FIGS.
[0039]
Moreover, in the high frequency module of the present invention, all of the modules shown in FIGS. 1 to 3 include the lids 3 and 3 ′, the cavities 4 and 4 ′, the high frequency elements 5 and 5 ′, and the first lines 6 and 6 ′. Although formed on the same dielectric substrate 2, the present invention is not limited to this, and the lid 3, the cavity 4, the high-frequency element 5, and the first line 6 are provided on the dielectric substrate 2, and the lid 3 A structure in which ', cavity 4', high-frequency element 5 ', and first line 6' are formed on another dielectric substrate 2 'may be employed.
[0040]
Further, the lid bodies 3 and 3 ′ have been described as separate bodies, but the lid bodies 3 and 3 ′ may have any structure that can electromagnetically shield the high-frequency elements 5 and 5 ′ individually. 3 'is completely integrated and separated into first and second cavities by the wall 3a, or the lid 3, 3' has a structure in which the opening of the wall 3a is covered with the lid 3b. It may be an integrated lid that is constituted by the wall 3a and the lid 3b and is separated into the first and second cavities by the wall 3a.
[0041]
Further, in the cavities 4 and 4 ', other high frequency elements and low frequency elements may be incorporated in addition to one high frequency element, and three or more electromagnetic coupling portions exist in one cavity. There is no problem.
[0042]
According to the present invention, when three or more cavities are provided on the surface of the dielectric substrate and the high frequency elements are accommodated in the respective cavities, the structure between the three or more high frequency elements is the same as described above. May be interconnected, or there may be independent high frequency elements that are not interconnected.
[0043]
Further, in the high frequency module of the present invention, a matching circuit is provided between the connection ends of the second line 7 and the first lines 6 and 6 ′, or electronic components are connected to and interposed between the lines. You may do it.
[0044]
Furthermore, in the present invention, a signal is directly transmitted to the antenna element or the like by connecting a waveguide or the like from the first line 6 through the slot hole 9 to the high-frequency element at the end of the module. Is possible.
[0045]
【The invention's effect】
As described above in detail, the connection structure of the high-frequency wiring board according to the present invention includes, for example, a first line in each cavity containing a high-frequency element in a high-frequency module and the like, and a second line formed outside the cavity. Since the high-frequency signal transmission line does not pass through the wall for forming the cavity, the signal is transmitted between the lines and between the high-frequency circuit elements with low transmission loss. And can be easily and inexpensively manufactured. In addition, the cavity in which the high-frequency element and the first line are accommodated is electromagnetically shielded by a conductive layer, etc., so that the effects of external electromagnetic waves and the influence between elements and lines can be reduced with a very simple structure. Therefore, it is possible to provide a high-frequency module that can be prevented and can be miniaturized with high reliability.
[Brief description of the drawings]
FIG. 1 is an exploded cross-sectional view showing a first embodiment of a high-frequency module that is an application example of a connection structure for a high-frequency wiring board according to the present invention.
FIG. 2 is an exploded cross-sectional view showing a second embodiment of a high frequency module which is an application example of the connection structure of the high frequency wiring board of the present invention.
FIG. 3 is an exploded cross-sectional view showing a third embodiment of a high frequency module which is an application example of the connection structure of the high frequency wiring board of the present invention.
FIG. 4 is a schematic cross-sectional view showing the structure of a conventional high-frequency module.
[Explanation of symbols]
1, 14, 15 High-frequency module 2 First dielectric substrate 3 Lid 4 Cavity 5 High-frequency element 6 First high-frequency transmission line 7 Second high-frequency transmission line 8, 10 Ground layer 9 Slot hole 11 Via hole 12 Second Dielectric substrate

Claims (4)

Is formed on the first dielectric substrate and the first dielectric substrate surface high frequency device and the first mounted on the dielectric surface of the substrate, was one end connected to the high frequency device and the electrical a high frequency wiring board having a first high frequency transmission line path,
Surface or the slot holes are ground layer provided is formed, it comprises a second dielectric substrate second high frequency transmission line path is formed inside or back surface,
Together consist of a low dielectric constant material than the second dielectric substrate is the first dielectric substrate, said first high-frequency transmission line in the high frequency wiring board, said in the second dielectric substrate connection structure of a high frequency wiring board, characterized in that a second high-frequency transmission line, formed by electromagnetically connected via the slot hole formed in the ground layer. Is formed on the first dielectric substrate and the first dielectric substrate surface high frequency device and the first mounted on the dielectric surface of the substrate, was one end connected to the high frequency device and the electrical A high-frequency wiring board having a ground layer formed on the back surface of the first high-frequency transmission line and the first dielectric substrate and provided with a slot hole;
A second dielectric substrate having a second high-frequency transmission line formed therein or on the back surface,
Together consist of a low dielectric constant material than the second dielectric substrate is the first dielectric substrate, said first high-frequency transmission line in the high frequency wiring board, said in the second dielectric substrate connection structure of a high frequency wiring board, characterized in that a second high-frequency transmission line, formed by electromagnetically connected via the slot hole formed in the ground layer. 3. The connection structure for a high-frequency wiring board according to claim 1, wherein the first high-frequency transmission line is composed of one type selected from a microstrip line, a coplanar line, and a coplanar line with a ground. 3. The connection structure for a high-frequency wiring board according to claim 1, wherein the second high-frequency transmission line is composed of one selected from a microstrip line, a coplanar line, a grounded coplanar line, and a triplate line.

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