JP2004363276A - High-frequency circuit module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a high-frequency circuit module in which the reflection of a high frequency generated in the connecting section of a carrier substrate and a main substrate is reduced and the deterioration of high-frequency characteristics by the connecting section of the carrier substrate and the main substrate is prevented. <P>SOLUTION: The high-frequency circuit module has the main substrate 103, the carrier substrates 102 loaded on the main substrate 103, a semiconductor element 101 joined on the carrier substrates and connecting sections 108 connecting a first signal conductor 105 on the main substrate and second signal conductors 106 on the carrier substrates. The surface height of the carrier substrates is constituted so as to coincide with that of the main substrate, and discontinuous sections of impedance in the connecting sections are eliminated while a distribution constant line such as a microstrip line transmitting a high-frequency signal is connected continuously without a shape change. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-frequency circuit module that prevents deterioration of high-frequency characteristics due to a connection between a carrier substrate and a main substrate.
[0002]
[Prior art]
In general, high-frequency semiconductor elements having a signal frequency exceeding several GHz are often mounted on a substrate with bare chips for reasons such as miniaturization of equipment and improvement of high-frequency characteristics. Repairability became an issue.
A conventional high-frequency circuit module is configured by mounting a carrier substrate to which a semiconductor element is bonded on a main substrate by soldering. In addition, when a failure occurs, the semiconductor element can be repaired by replacing the soldered carrier substrate (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP 2002-158509 A
[Problems to be solved by the invention]
As described above, since the conventional high-frequency circuit module connects the high-frequency line and the ground with solder or the like via the connection electrode, there is a discontinuity in the connection portion such as a step, so that the frequency is low. There is a problem that the reflection amount increases as the height increases, and the transmission characteristics deteriorate.
[0005]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a high-frequency signal is transmitted by eliminating a discontinuity in impedance at a connection portion of a signal line (and ground) due to soldering or the like. Continuously connect distributed constant lines such as microstrip lines without changing the shape, reduce high-frequency reflection that can occur at the connection between the carrier substrate and the main substrate, and improve the high-frequency characteristics due to the connection between the carrier substrate and the main substrate. An object is to obtain a high-frequency circuit module in which deterioration is prevented.
[0006]
[Means for Solving the Problems]
A high-frequency circuit module according to the present invention includes a main substrate, a carrier substrate mounted on the main substrate, a semiconductor element bonded on the carrier substrate, a first signal line on the main substrate, and a first signal line on the carrier substrate. A connection portion for connecting the second signal line to the second signal line, wherein a surface height of the carrier substrate is configured to be equal to a surface height of the main substrate.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a plan view and a side sectional view partially showing in detail a first embodiment of the present invention.
In FIG. 1, the high-frequency circuit module includes a semiconductor element 101 such as an MMIC (Monolithic Microwave IC), a carrier substrate 102 to which the semiconductor element 101 is bonded, and a main substrate 103 on which the carrier substrate 102 is mounted.
[0008]
A counterbore 104 having the same depth as the thickness of the carrier substrate 102 is formed at a position on the upper surface of the main substrate 103 where the carrier substrate 102 is mounted, and the carrier substrate 102 is positioned and inserted into the counterbore 104. By doing so, the surface height of the carrier substrate 102 is configured to match the surface height of the main substrate 103.
A first signal line 105 composed of a microstrip line is provided on the upper surface of the main substrate 103, and a second signal line 106 composed of a similar microstrip line is provided on the upper surface of the carrier substrate 102. The signal lines 105 and 106 are electrically connected via a connection unit 108.
[0009]
In the main substrate 103, a ground 107 for a high-frequency signal line composed of a distributed constant line is provided so as to be exposed at the bottom of the counterbore 104, and the ground 107 contacts the bottom of the carrier substrate 102. As a result, it is connected to the ground of the carrier substrate 102 and also serves as the ground of the distributed constant line on the carrier substrate 102.
Further, on the side surface of the carrier substrate 102, a concave connection electrode 110 for connecting a high frequency signal and a low frequency signal is formed as shown in detail in a two-dot chain line frame in FIG.
[0010]
Next, a mounting procedure in the case where the main substrate 103 is formed of a multilayer substrate will be described with reference to FIGS.
FIG. 2 is a side view showing a mounting structure in a case where the main substrate 103 in FIG. 1 is composed of a multilayer (two-layer) substrate, that is, an upper first layer 201 and a lower second layer 202.
In FIG. 2, a through hole 204 corresponding to the counterbore hole 104 is formed in the center of the first layer 201, and a ground 107 is provided on the upper surface of the second layer 202.
[0011]
In FIG. 1, a semiconductor element 101 is bonded and mounted on a carrier substrate 102, and the carrier substrate 102 is mounted in a counterbore 104 of a main substrate 103.
The first signal line 105 on the main substrate 103 and the second signal line 106 on the carrier substrate 102 are connected via a connection unit 108. The high-frequency ground 107 of each of the signal lines 105 and 106 is provided only on the main substrate 103.
[0012]
As the material of the carrier substrate 102 and the main substrate 103, all the substrate materials such as glass epoxy, ceramic, and Teflon (registered trademark) can be used.
Here, a case where the most typical microstrip line is used as each of the signal lines 105 and 106 which are high-frequency signal lines when the carrier substrate 102 and the main substrate 103 are made of the same material will be described as an example.
By manufacturing both microstrip lines on the carrier substrate 102 and the main substrate 103 in the same shape, equivalent performance (characteristic impedance, wavelength shortening rate) can be obtained. , 106 can be connected to the carrier substrate 102 and the main substrate 103 most continuously without any change.
[0013]
On the other hand, as shown in FIG. 2, a through hole 204 is formed in the first layer 201 of the main substrate 103 and a microstrip is formed on the upper surface of the second layer 202 in order to manufacture the recessed counterbore 104 in the main substrate 103. An earth 107 composed of a line is provided.
Here, if the thickness of the first layer 201 is 0.3 mm, the relative dielectric constant is 3.76, and the conductor thickness L1 of the first layer 201 of the main substrate 103 is 0.05 mm, the width of the second signal line 106 is Is set to 0.55 mm, a microstrip line having a characteristic impedance of 50Ω can be formed.
[0014]
Further, as described above, the high-frequency semiconductor element 101 such as an MMIC is mounted on the carrier substrate 102 by flip chip or wire bonding, but the semiconductor element (MMIC) 101 mounted on the carrier substrate 102 has It is necessary to connect not only a high frequency signal but also a power supply, a ground, and a low frequency signal.
For this purpose, similarly to the high-frequency signal line, the conductor of the first layer 201 of the main substrate 103 and the surface of the carrier substrate 102 on which the MMIC 101 is mounted can be connected by the respective signal lines 105 and 106. It is.
[0015]
However, in this case, a pattern of a power supply, a ground, and a low-frequency signal is provided on the second layer 202 of the main substrate 103, and this pattern is connected to the concave connection electrode 110 (see FIG. The high frequency signal and the low frequency signal are supplied to the semiconductor element (MMIC) 101 by soldering to the two-dot chain line frame).
FIG. 3 is a plan view showing a mounting structure using the recess connection electrode 110. FIG.
In FIG. 3, a connection portion 108 is formed in the recess connection electrode 110, and the pattern of the ground 107 and the high-frequency signal line 306 on the main substrate 303 is connected to the MMIC 301 on the carrier substrate 302 via the connection portion 108. ing.
[0016]
As described above, the height of the surface of the carrier substrate 102 to which the semiconductor element 101 is bonded and the height of the surface of the main substrate 103 on which the carrier substrate 102 is mounted are matched, so that the signal lines 105 and 106 are connected without any step. Therefore, deterioration of high-frequency characteristics due to reflection at the connection portion 108 between the carrier substrate 102 and the main substrate 103 can be reduced as much as possible.
In addition to the signal lines 105 and 106 as well as the ground 107, a distributed constant line such as a microstrip line for transmitting a high-frequency signal is formed by avoiding as much as possible the occurrence of a discontinuity in the connection impedance due to soldering or the like. Can be continuously connected without a change in shape, high-frequency reflection that can occur at a connection portion 108 between the carrier substrate 102 and the main substrate 103 can be further reduced, and deterioration of high-frequency characteristics due to the connection portion 108 can be reduced. Can be prevented.
[0017]
Embodiment 2 FIG.
In the first embodiment, the ground 107 on the main substrate 103 side is connected to the carrier substrate 102, but the ground 107 may be provided only in relation to the main substrate 103.
FIG. 4 is a side sectional view showing main substrate 403 according to the second embodiment of the present invention in which ground 107 is provided only on the main substrate.
Here, a microstrip line in the case where the main substrate 403 is a single-layer substrate will be described.
[0018]
In FIG. 4, a counterbore 104 is provided on the upper surface of a main substrate 403 made of a single-layer substrate.
In addition, a ground 107 is provided on the lower surface of the main substrate 403 opposite to the surface on which the counterbore 104 is formed.
The other configuration is the same as that described above (see FIG. 1) except that the cross-sectional shape of the main substrate 403 is different.
[0019]
Also in this case, by providing the carrier substrate 102 (see FIG. 1) in the counterbore 104, a step at the connecting portion 108 can be eliminated.
However, the carrier substrate 102 does not contact the ground 107, and the carrier substrate 102 is not provided with a ground for a high-frequency signal line.
If the dielectric constant of the carrier substrate 102 and that of the main substrate 403 are the same (preferably, the same material is preferable), the signal lines 105 and 106 are formed to have the same width, so that the signal lines 105 and 106 are formed. Of the signal lines 105 and 106 can be connected at the connection unit 108 without causing a change in the shape of the signal lines 105 and 106.
As described above, by providing the ground 107 made of a distributed constant line only on the main substrate 403, the connection portion of the ground 107 between the main substrate 403 and the carrier substrate 102 can be eliminated, and the carrier substrate 102 and the main substrate The reflection at the connection portion 108 of the high-frequency signal line such as the distributed constant line 403 can be reduced as much as possible.
[0020]
Embodiment 3 FIG.
In the first and second embodiments, the case where the carrier substrate and the main substrate are made of the same material is described as an example. However, the carrier substrate and the main substrate may be made of different materials.
FIG. 5 is a plan view showing a third embodiment of the present invention in which the carrier substrate 502 and the main substrate 503 are made of different materials.
[0021]
In FIG. 5, a first signal line 505 on a main substrate 503 and a second signal line 506 on a carrier substrate 502 are formed to have different widths, and a connection portion of each of the signal lines 505 and 506 is , And a tapered portion 508.
The main substrate 503 is formed of an organic substrate having a relative dielectric constant of 3.76, and the carrier substrate 502 is formed of a Teflon (registered trademark) substrate having a relative dielectric constant of 2.00.
[0022]
In this case, since the relative dielectric constants of the main substrate 503 and the carrier substrate 502 are different from each other, if the microstrip line is manufactured so that the shapes such as the substrate thickness and the line width are the same, the characteristic impedance will be different. Reflection characteristics deteriorate.
Therefore, in order to make the characteristic impedance of the microstrip line of the main substrate 503 and the carrier substrate 502 the same, it is necessary to change the thickness of the substrate or the width of each signal line 505, 506 as shown in FIG. .
At this time, an equation for calculating the characteristic impedance Z of the microstrip line is expressed as follows.
[0023]
Z = 60 / {(0.475εr + 0.67) × ln {4h / 0.67 (0.8w + t)}}
[0024]
In the above equation, εr is the relative dielectric constant of the material of the dielectric substrate, h is the thickness of the dielectric, t is the thickness of the high-frequency signal conductor, and w is the width of the high-frequency signal line.
Here, if the thicknesses of the main substrate 503 and the carrier substrate 502 are changed, a step is generated between the main substrate 503 and the carrier substrate 502. Therefore, it is necessary to change the widths of the signal lines 505 and 506. It turns out that it cannot be obtained.
[0025]
As described above, when the material of the carrier substrate 502 and the material of the main substrate 503 are different from each other and the widths of the signal lines 505 and 506 are different from each other, the pattern of the connection portion is formed by the taper portion 508 as shown in FIG. By doing so, the characteristic impedance of the distributed constant line can be made the same while the thickness of the carrier substrate 502 and the depth of the counterbore hole 104 are made the same, and the reflection at the connection portion can be reduced as much as possible.
Further, as shown in FIG. 4, the pattern of the connection portion can be formed in a coplanar structure.
[0026]
【The invention's effect】
As described above, according to the present invention, the main substrate, the carrier substrate mounted on the main substrate, the semiconductor element bonded on the carrier substrate, the first signal line on the main substrate, and the A connection portion for connecting the second signal line to the second signal line, wherein the surface height of the carrier substrate is configured to coincide with the surface height of the main substrate, and the impedance of the connection portion is reduced. Discontinuous portions are eliminated, and distributed constant lines such as microstrip lines for transmitting high-frequency signals are connected continuously without shape change, so high-frequency reflections that can occur at the connection between the carrier substrate and the main substrate are eliminated. Thus, there is an effect that a high-frequency circuit module can be obtained in which the high-frequency circuit module is prevented from deteriorating due to the connection between the carrier substrate and the main substrate.
[Brief description of the drawings]
FIG. 1 is a plan view, a side cross-sectional view, and a main part detailed view showing Embodiment 1 of the present invention.
FIG. 2 is a side sectional view showing a configuration example of a main substrate according to the first embodiment of the present invention.
FIG. 3 is a plan view showing a mounting example of a connection unit according to the first embodiment of the present invention.
FIG. 4 is a side sectional view showing a configuration example of a main substrate according to a second embodiment of the present invention.
FIG. 5 is a plan view showing a third embodiment of the present invention.
[Explanation of symbols]
101 semiconductor element, 102, 302, 502 carrier substrate, 103, 303, 403, 503 main substrate, 104 counterbore, 105, 505 first signal line, 106, 506 second signal line, 107 ground, 108 connection , 110 concave connection electrode, 301 MMIC, 508 tapered portion.

Claims (6)

A main board,
A carrier substrate mounted on the main substrate,
A semiconductor element bonded on the carrier substrate,
A high-frequency circuit module comprising: a connection portion that connects a first signal line on the main substrate and a second signal line on the carrier substrate,
The high-frequency circuit module according to claim 1, wherein a surface height of the carrier substrate is equal to a surface height of the main substrate. A concave connection electrode formed on a side surface of the carrier substrate,
Comprising a low-frequency signal pattern disposed on the main board,
The semiconductor device is made of an MMIC,
The high-frequency circuit module according to claim 1, wherein the pattern is electrically connected to the recess connection electrode. The main substrate is
A first layer having a through hole into which the carrier substrate is inserted;
The first layer is constituted by a second layer laminated on the upper surface,
An earth composed of a distributed constant line is provided on the upper surface of the second layer,
3. The high-frequency circuit module according to claim 1, wherein the ground is connected to the carrier substrate, and also serves as a ground for a distributed constant line on the carrier substrate. The main substrate is
Having a concave-shaped hole on the upper surface into which the carrier substrate is inserted,
The high-frequency circuit module according to claim 1, wherein a ground made of a distributed constant line is provided on a lower surface located on a side opposite to a surface on which the hole is formed. The main substrate and the carrier substrate are made of the same material,
The high-frequency circuit module according to any one of claims 1 to 4, wherein the first and second signal lines are formed to have the same width in the connection part. The main substrate and the carrier substrate are made of different materials,
In the connection portion, the first and second signal lines are formed to have different widths from each other,
The high-frequency circuit module according to any one of claims 1 to 4, wherein the connection portion is configured by a tapered portion.

Images