JP2008244924A - Directional coupler and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for reducing a directional coupler in size. <P>SOLUTION: A directional coupler 10 comprises a wiring board having a plurality of stacked insulating layers and a plurality of wiring layers wired in a specified pattern on the surface of respective insulating layers, a main line (first wiring) 11 that is formed in a single wiring layer among the plurality of wiring layers, and a sub line (second wiring) 12 which is formed across the plurality of wiring layers and comprises extensions 13a, 13b and 13c extending along the main line 11. The main line 11 comprises no bent part while the sub line 12 is formed to form a coil-like loop on one side surface side of the main line 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a directional coupler technology and a semiconductor device technology, and more particularly to a technology effective when applied to power detection of a high-frequency circuit mounted in a mobile communication device.

  Mobile communication devices such as cellular phones include, for example, surface-mounted semiconductor chips on which power amplifiers or antenna switches are formed, and surface-mounted chip components on which capacitors or resistors are formed. However, a semiconductor module having a structure mounted on a wiring board is employed. Such a semiconductor module is called an RF (Radio Frequency) module.

  In order to reduce power consumption of mobile communication devices and interference between communication device terminals, high-frequency circuits such as RF modules require fine control of transmission power.

  There is a directional coupler as a power detection device for controlling the output of a high-frequency circuit such as an RF module. Directional couplers using two electromagnetic couplings, capacitive coupling and inductive coupling, have been put to practical use as devices that detect output power without having metallic contact with the antenna signal transmission line to be measured. Yes.

  A directional coupler detects the electric power which flows through a main line by extending a detection line (henceforth a subline) along an antenna signal transmission line (henceforth a main line). Here, a direction characteristic of ∞ can be obtained in principle by placing a sub-line having a length corresponding to a quarter wavelength at a frequency to be detected along the main line.

  However, the quarter-directional coupler has a length of several centimeters in a high frequency band used for a mobile phone or the like, and cannot withstand the demand for miniaturization of components.

  In order to ensure electrical coupling between the main line and the sub-line in a limited area, there are directional couplers that meander the main line and the sub-line in a meander shape or wind in a spiral shape or a helical shape.

For example, in Japanese Patent Application Laid-Open No. 2003-133817 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2006-74830 (Patent Document 2), as a structure for increasing the length of the sub line along the main line with a limited area, A structure of a directional coupler that circulates a sub-line spirally is disclosed.
JP 2003-133817 A JP 2006-74830 A

  In recent years, mobile communication devices such as mobile phones have a need for miniaturization and weight reduction, and accordingly, components mounted on circuit boards are also required to be miniaturized.

  The inventor has studied the miniaturization of the directional coupler and found the following problems.

  In general, a directional coupler is a four-end circuit consisting of a main line having both ends and a sub-line having both ends, and a part of signal power passing between both ends of the main line is electromagnetically coupled to the main line. It is configured to be taken out from the end of one side by a sub line.

  The performance index of the directional coupler is represented by transmission loss (also referred to as insertion loss), coupling degree, and directionality. Transmission loss is defined by the ratio of the power input to the input end of the main line and the power extracted at the output end of the main line. The degree of coupling is defined by the ratio of the power input to the main line and the power extracted by the sub line, and the directionality is the ratio of the traveling wave (or reflected wave) on the main line appearing at both ends of the sub line. Defined by

  The smaller the transmission loss, the better for reducing the power consumption of the high-frequency circuit. In addition, the higher the degree of coupling, the greater the power that can be extracted to the sub-line side. For applications in which only traveling waves are separated and detected, such as a directional coupler mounted on an RF module of a mobile communication device, the higher the directionality, the better.

  As disclosed in Japanese Patent Laid-Open No. 2003-133817 (Patent Document 1), when a directional coupler is mounted on a circuit board as an individual element, there is a restriction on the mounting position of the external terminal for connection to the circuit board. For this reason, the main line must be bent. In addition, since the characteristic design of the directional coupler becomes difficult with downsizing, the main line may be inevitably formed in a plurality of layers depending on the wiring shape of the sub line.

  If the main line is bent or formed over a plurality of layers in this way, the transmission loss (also referred to as insertion loss) of the main line increases as compared with the case where the main line is formed linearly.

  In order to reduce the power consumption of mobile phones, etc., it is essential to reduce the transmission loss of high-frequency equipment. If the transmission loss of the main line increases even when downsizing, the power consumption of the high-frequency circuit will eventually increase. It will increase.

  Moreover, since the directional coupler disclosed in Patent Document 1 has a complicated shape of the sub-line on both sides of the linear portion of the main line in order to obtain a predetermined degree of coupling in a limited area, The degree of freedom in designing the power detection circuit is reduced. In addition, since the main line and the sub line are intertwined in a complicated manner, the characteristic design becomes difficult.

  As described above, there is a problem that a desired characteristic cannot be obtained by simply increasing the length of the sub-line along the main line, or that transmission loss increases, and there is a limit to downsizing.

  An object of the present invention is to provide a technique capable of downsizing a directional coupler.

  Another object of the present invention is to provide a technique capable of improving the degree of freedom in designing the characteristics of a directional coupler.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  That is, a wiring board having a plurality of laminated insulating layers and a plurality of wiring layers in which wirings are formed in a desired pattern on the respective surfaces of the plurality of insulating layers, and a single of the plurality of wiring layers A directional coupler comprising: a first wiring formed in the wiring layer; and a second wiring formed over the plurality of wiring layers and provided with an extending portion extending along the first wiring. Thus, the first wiring does not have a bent portion, and the second wiring is formed so as to form a coil-shaped loop on one side surface of the first wiring.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  That is, according to the present invention, the directional coupler can be reduced in size.

  Components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof is omitted in principle. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
In the first embodiment, an RF module, which is a high-frequency circuit module mounted on a mobile communication device such as a mobile phone, will be described as an example of a semiconductor device incorporating a directional coupler.

  FIG. 1 is a plan view showing the main components of the RF module according to the first embodiment. In FIG. 1, a directional coupler 10 is built in a wiring board 1 provided in an RF module (semiconductor device) 100. In addition, a semiconductor chip (semiconductor element) 20 and an antenna switch 30 are mounted on the wiring board 1.

  The wiring substrate 1 has a multilayer structure in which a plurality of dielectric insulating layers such as dielectric ceramics are stacked, and each insulating layer has a wiring layer in which wiring is formed in a desired pattern on the surface of each insulating layer. Yes. The structure of the insulating layer of the wiring board 1 will be described in detail when the detailed structure of the directional coupler 10 is described.

  One end of the transmission power wiring 2 is electrically connected to the transmission power output terminal 21 of the semiconductor chip 20. The transmission power wiring 2 is wired so as to pass through the output matching circuit 40, the directional coupler 10, and the low-pass filter 50 in this order, and the opposite end is electrically connected to the input terminal 31 of the antenna switch 30. It is connected to the.

  Although not shown in FIG. 1, the uppermost layer of the wiring board 1 is sealed with a sealing resin. The state sealed with this sealing resin will also be described when the detailed structure of the directional coupler 10 is described.

  Next, the flow of power when the mobile communication device performs a transmission operation will be described using FIG. 2 which is an equivalent circuit of the RF module 100 shown in FIG. FIG. 2 is an equivalent circuit diagram of the RF module shown in FIG.

  First, the transmission signal current input to the transmission input terminal 101 is amplified by the power amplifier 22 formed in the semiconductor chip 20. The amplified current is impedance-converted by the output matching circuit 40, and then input to the input terminal 31 of the antenna switch 30 via the directional coupler 10 and the low-pass filter 50, and the antenna output terminal of the RF module 100 The signal is output to an antenna (not shown) via 102.

  Here, when the current amplified by the power amplifier 22 flows through the main line (first wiring) 11 of the directional coupler 10, it is transmitted by the sub line (second wiring) 12 formed in the directional coupler 10. Part of the power is taken out. Part of the transmission power extracted by the sub line 12 is fed back to the semiconductor chip 20, and the voltage of the transmission power is detected by the detector 23 formed in the semiconductor chip 20.

  A bias voltage adjustment circuit 24 is also formed in the semiconductor chip 20. The bias voltage adjustment circuit 24 adjusts the gain of the power amplifier 22 while referring to the voltage detected by the detector 23, and a desired transmission power is obtained. It has come to be obtained.

  Thus, the directional coupler 10 has a function of detecting the power flowing through the transmission power wiring and feeding it back to the semiconductor chip 20.

  Next, the detailed structure of the directional coupler 10 according to the first embodiment will be described with reference to FIGS. 3 and 4. 3 is an enlarged cross-sectional view taken along line AA shown in FIG. 1, and FIG. 4 is a perspective view showing the structure of the main line and the sub line of the directional coupler portion of the RF module shown in FIG.

  In FIG. 3, the wiring substrate 1 has a structure in which a plurality of dielectric insulating layers 3 such as dielectric ceramics (three layers in FIG. 3) are laminated, and the uppermost layer is sealed with a sealing resin 4. It has a structure.

  The directional coupler 10 shown in FIG. 1 has a structure built in the wiring board 1 of the RF module 100, and the entire wiring board 1 of the RF module 100 shown in FIG. The insulating layer 3 is stacked, and the uppermost layer of the wiring substrate 1 is sealed with a sealing resin 4.

  In FIG. 4, the insulating layer 3 and the sealing resin 4 shown in FIG. 3 are not shown in order to facilitate the explanation of the structure of the main line and the sub line. In the following description of the embodiments, the illustration of the insulating layer and the sealing resin is omitted for the perspective view showing the structure of the main line and the sub line.

  3 and 4, the main line 11 is formed in the uppermost layer among the plurality of wiring layers provided in the wiring board 1. That is, the main line 11 is not formed over a plurality of wiring layers, but is formed in a single layer.

  The transmission signal current amplified by the power amplifier 22 described in FIG. 2 flows in the direction from the input end 11a of the main line 11 to the output end 11b. Since the directional coupler 10 has the main line 11 formed in a single layer, the transmission loss of the transmission signal current can be reduced.

  The main line 11 is formed in a substantially straight line from the input end 11a to the output end 11b. This substantially straight line means that the sub-line 12 does not have a bent portion, and does not exclude the case where the line becomes slightly non-linear due to a processing accuracy error or the like.

  Here, the main line 11 is a part of the transmission power wiring 2 shown in FIG. That is, the sub-line 12 is arranged on one side surface of the place where the transmission power wiring 2 is arranged substantially linearly, and the region arranged in parallel with the extending portion of the sub-line 12 is the main part of the directional coupler 10. The track 11 is considered.

  Since the directional coupler 10 of the first embodiment is formed so that the main line 11 does not have a bent portion, it is possible to reduce transmission loss of the transmission signal current.

  Moreover, since the main line 11 should just be formed in a substantially straight line on a single layer, the directional coupler 10 can be placed at an arbitrary position of the transmission power wiring 2 of the RF module 100 shown in FIG. Can be built in. That is, it is possible to improve the degree of freedom in designing the place where the directional coupler 10 is mounted.

  Further, when the main line 11 is regarded as a part of the transmission power wiring 2 shown in FIG. 1, when the main line 11 shown in FIG. 3 is formed on the surface of the insulating layer 3 other than the uppermost layer of the wiring board 1, FIG. The wiring path of the shown transmission power wiring 2 extends over a plurality of layers.

  For this reason, the transmission loss increases as compared with the case where the transmission power wiring 2 is formed on the surface of the uppermost insulating layer 3 of the wiring substrate 1. In the first embodiment, it is possible to reduce transmission loss of transmission signal power by forming the main line 11 of the directional coupler 10 on the surface of the uppermost insulating layer 3 of the wiring board 1.

  Next, as shown in FIG. 3, the sub-line 12 is formed across a plurality of layers on one side of the main line 11 extending on the surface of the uppermost insulating layer 3 of the wiring board 1. The sub-line 12 includes a surface wiring 13 (see FIG. 4) formed in the wiring layer on the surface of each insulating layer 3, and a via 15 that is a conductive path for electrically connecting the surface wiring.

  In the first embodiment, for ease of explanation, the wiring board 1 of the RF module 100 (see FIG. 1) is described as having a structure in which three insulating layers 3 are stacked. The surface wiring 13 of the line 12 is not necessarily formed on the surface of all the insulating layers 3.

  For example, when the wiring board 1 is composed of four or more insulating layers 3, the surface wiring 13 of the sub line 12 described in the first embodiment may be formed in any three of them.

  The surface wiring 13 has extending portions 13 a, 13 b, and 13 c that extend along the main line 11. The extending portions 13 a, 13 b and 13 c are formed so as to be substantially parallel to the main line 11. The degree of parallelism is not limited as long as the main line 11 and the sub line 12 have a degree of parallelism that can obtain a predetermined degree of coupling. It is not excluded.

  By providing the extending portions 13a, 13b, and 13c as described above, the main line 11 and the extending portions 13a, 13b, and 13c can be capacitively coupled. For example, in FIGS. 3 and 4, focusing on the main line 11 and the extending portion 13 b formed in the second layer, the main line 11 and the extending portion 13 b are parallel to each other via the dielectric insulating layer 3. Can be regarded as a capacitor arranged in

  The capacitance of the capacitor is defined by the area of the mutually facing surfaces of the conductors arranged in parallel, the distance between the conductors, and the dielectric constant of the dielectric interposed between the conductors. The capacity increases as the area of the opposing surfaces of the conductor increases and as the distance between the conductors decreases.

  For this reason, when the transmission signal current flows through the main line 11, the extending portions 13 a, 13 b, and 13 c become capacitors that form a pair with the main line 11, and a part of the transmission signal power can be taken out.

  Moreover, the directional coupler 10 of this Embodiment 1 can set the distance of extension part 13a, 13b, 13c and the main line 11 for each layer separately. Thus, by setting the distances between the extending portions 13a, 13b, and 13c and the main line 11 for each layer individually, it is possible to easily adjust the coupling degree of capacitive coupling.

  For example, in the first embodiment, as shown in FIG. 4, the distance between the extension 13b formed in the second layer and the main line 11 is the same as the extension a and the main line formed in the uppermost layer. 11 is set so as to be shorter than the distance to 11. Thus, the distance between the extended portion 13b formed in the layer where the main line 11 is not formed and the main line 11 is determined from the distance between the extended portion 13a of the layer where the main line 11 is formed and the main line 11. By shortening the length, it is possible to improve the degree of capacitive coupling.

  Although FIG. 4 illustrates the case where only the extending portion 13b is brought closer to the main line 11, the extending portion 13c may be brought closer to the main line 11 instead of the extending portion 13b. Further, both the extending portions 13 b and 13 c may be brought close to the main line 11. In this case, the coupling degree of capacitive coupling can be further improved.

  Moreover, the distance between the main line 11 and the extending portions 13b and 13c can be adjusted by changing the thickness of the insulating layer 3 shown in FIG. By setting the thickness of the insulating layer to be different for each layer, it is possible to adjust the degree of coupling due to capacitive coupling between the main line 11 and the extending portions 13b and 13c.

  For example, in FIG. 3, in order to improve the capacitive coupling between the main line 11 and the extending portion 13b, the thickness of the uppermost insulating layer may be made thinner than the thickness of the second insulating layer.

  The directional coupler 10 according to the first embodiment can obtain a desired degree of coupling by arbitrarily adjusting the distance between the main line 11 and the extending portions 13a, 13b, and 13c. The degree of freedom can be improved.

  Next, as shown in FIGS. 3 and 4, each surface wiring 13 of the sub-line 12 has a bent portion at a predetermined position, and the entire wiring is formed so as to form a coil-shaped loop. In the first embodiment, a three-layered coil-shaped sub line 12 is used.

  Here, when a transmission signal current flows through the main line 11, a magnetic field is generated around the main line 11. Therefore, when the sub line 12 is formed in a coil shape, the magnetic flux is surrounded by a loop of the sub line 12 (first An induced electromotive force is generated in the sub line 12.

  That is, the sub line 12 can extract part of the transmission signal power by inductively coupling with the main line 11.

  As shown in FIGS. 3 and 4, in the circuit in which the sub-line 12 is in a coil shape, the degree of coupling due to inductive coupling is larger than the circuit in which the straight sub-line 12 is simply arranged along the main line 11. Become. That is, the degree of inductive coupling can be improved by forming the sub-line 12 so as to form a coil-shaped loop.

  Further, since the coil-shaped loop of the sub line 12 is formed only on one side surface side of the main line 11, the main line 11 is not limited by the wiring shape of the sub line 12. For this reason, the structure of the main line 11 can be made a preferable structure from the viewpoint of transmission loss. That is, it is possible to form the main line 11 having no bent portion in a single wiring layer.

  Further, in the directional coupler 10 according to the first embodiment, the areas of the regions (first regions) 14a, 14b, and 14c surrounded by the loops of the surface wirings 13 can be set individually for each layer. In this manner, by individually setting the areas of the regions 14a, 14b, and 14c surrounded by the loops of the respective surface wirings 13, it is possible to easily adjust the degree of coupling of inductive coupling.

  For example, in the first embodiment, as shown in FIG. 4, the area 14b surrounded by the loop of the second-layer surface wiring 13 is surrounded by the uppermost surface wiring 13 on which the main line 11 is formed. The area is set to be larger than the area of the region 14a.

  Thus, the area of the regions 14b and 14c surrounded by the surface wiring 13 of the layer where the main line 11 is not formed is larger than the area of the region 14a surrounded by the surface wiring 13 of the layer where the main line 11 is formed. By doing so, it becomes possible to improve the degree of coupling by inductive coupling.

  Although FIG. 4 illustrates the case where only the area of the region 14b is increased, the area of the region 14c may be increased instead of the region 14b. Further, the area of both the regions 14b and 14c may be larger than the area of the region 14a. In this case, the degree of inductive coupling can be further improved.

  Next, the direction in which the current generated when the transmission signal current flows through the main line 11 flows through the sub line 12 will be described.

  As shown in FIG. 4, the sub-line 12 has a coil shape as a whole. One end of the coil shape is a detection end 12a and the other end 12b. The coil shape of the sub line 12 is such that the direction (first direction) 16 from the terminal end 12 b to the detection end 12 a is opposite to the direction (second direction) 17 from the input end 11 a to the output end 11 b of the main line 11. It is formed as follows.

  Here, when a traveling wave of the transmission signal current flows in the direction 17 from the input end 11a to the output end 11b of the main line 11 shown in FIG. 4, the extension portions 13a, 13b, and 13c of the sub-line 12 are connected to the input end. A traveling wave current flows in the direction 16 opposite to the direction 17 from the 11a toward the output end 11b.

  For this reason, the directional coupler 10 of Embodiment 1 can efficiently detect the traveling wave of the transmission signal power. That is, the directional characteristic of the directional coupler 10 can be improved.

  The sub-line 12 is formed on one side of the main line 11, and the loop hole regions (first regions) 14a, 14b, and 14c surrounded by the loop of the coil-shaped sub-line 12 are all main lines. 11 is not superimposed.

  Here, “not overlapping” means that the positions of the main line 11 and the loop hole regions 14a, 14b, and 14c on the plane do not overlap when the directional coupler 10 is viewed from the upper surface or the lower surface.

  By arranging the loop hole regions 14a, 14b, and 14c so as not to overlap the main line 11 in this way, the direction of the magnetic flux that occurs when the transmission signal power flows through the main line 11 and penetrates the loop hole region is made uniform. Is possible.

  For this reason, the directional coupler 10 according to the first embodiment can improve the directional characteristics.

  Further, as shown in FIG. 4, the coil-shaped portion of the directional coupler 10 according to the first embodiment is formed on the upper surface wiring 13 as it proceeds in the direction 16 from the terminal end 12b of the sub line 12 toward the detection end 12a. Configured to be connected.

  By configuring the spiral structure of the sub-line 12 in this way, the detection end 12a of the sub-line 12 can be arranged in the uppermost layer.

  Next, as shown in FIG. 1, the detection end 12a (see FIG. 4) of the sub line 12 is electrically connected to a detection terminal 25 connected to the detector 23 (see FIG. 2) of the semiconductor chip 20. Yes. Since the semiconductor chip 20 is mounted on the uppermost layer of the wiring substrate 1, the detection end 12 a can be disposed on the uppermost layer, that is, the same layer as the layer on which the semiconductor chip 20 is mounted.

  By disposing the detection end 12a in the same layer as the layer on which the semiconductor chip 20 is mounted, the detection end 12a and the detection terminal 25 can be electrically connected without using an interlayer conductive path such as a via. For this reason, it becomes possible to transmit the detected electric power to the detector 23 efficiently.

  In addition, the termination 12 b that is the end of the sub-line 12 opposite to the detection end 12 a is electrically connected to a termination resistor element (termination resistor) 5 having a higher impedance than the wiring impedance of the sub-line 12. Since the generation of the reflected wave current can be suppressed by electrically connecting the terminal end 12b of the sub line to the terminal resistance element 5, the directional characteristic of the directional coupler 10 can be improved.

  Further, as shown in FIG. 1, by using a termination resistor element 5 such as a chip resistor as a termination resistor, it is easier than the case where an impedance adjustment circuit is formed in order to suppress the reflected wave current at the termination 12b. In addition, it becomes possible to improve the directivity characteristics.

  As described above, the directional coupler 10 according to the first embodiment can improve the coupling degree characteristic and the directional characteristic with a small area. For this reason, even if the directional coupler is reduced in size, it is possible to obtain desired characteristics, so that the directional coupler can be reduced in size.

  Moreover, since the freedom degree of the design layout of the main line 11 can be improved, it becomes possible to arrange the substantially linear main line 11 in a single layer. For this reason, the transmission loss of the directional coupler 10 can be reduced.

  Further, by adjusting the distance between the main line 11 and the extending portions 13a, 13b, and 13b and the areas of the regions 14a, 14b, and 14c surrounded by the loop of the sub-line 12, a desired degree of coupling characteristic can be obtained. As a result, the degree of freedom in characteristic design can be improved.

(Embodiment 2)
In the first embodiment, the embodiment in which the sub line of the directional coupler is arranged so as not to overlap the main line has been described. In the second embodiment, an embodiment in which a part of the sub line of the directional coupler is arranged so as to overlap with the main line will be described.

  FIG. 5 is an enlarged cross-sectional view of a directional coupler portion built in the wiring board of the RF module of the second embodiment, and FIG. 6 shows directional coupling built in the wiring board of the RF module of the second embodiment. It is a perspective view which shows the structure of the main track | line and subline | track of a container part.

  The plan view schematically showing the RF module of the second embodiment is the RF module shown in FIG. 1 except that the main line 11 of the directional coupler 10 is formed not in the uppermost layer but in the second layer. Since it is the same as 100, the illustration is omitted.

  The first difference between the directional coupler 10 of the RF module 100 described in the first embodiment and the directional coupler 10 of the second embodiment is a sub-layer formed in a wiring layer different from the main line 11. The extending portions 13 a and 13 c of the line 12 overlap with the main line 11.

  Here, overlapping means that the positions of the main line 11 and the extending portions 13a and 13c on the plane overlap when the directional coupler 10 is viewed from the upper surface or the lower surface. Compared with the method of reducing the distance between the main line 11 and the extension part 13b described in the first embodiment by overlapping the main line 11 and the extension parts 13a and 13c in this manner, The degree of coupling due to capacitive coupling with the sub-line 12 can be further improved.

  As shown in FIGS. 5 and 6, the directional coupler 10 according to the second embodiment is the direction described in the first embodiment as a method of superimposing the main line 11 and the extending portions 13a and 13c. Compared with the sexual coupler 10, a method of expanding the area of the loop hole regions 14 a and 14 c surrounded by the loop of the sub-line 12 rather than simply bringing the sub-line 12 closer to the main line 11 side is adopted. .

  By expanding the loop hole regions 14a and 14c in this manner, the degree of coupling by inductive coupling can be improved.

  However, the loop hole regions 14 a, 14 b and 14 c surrounded by the loop of the sub-line 12 are not overlapped with the main line 11. Thus, even when the extending portions 13 a and 13 c are overlapped with the main line 11, the transmission signal power flows through the main line 11 by not overlapping the loop hole regions 14 a, 14 b and 14 c with the main line 11. It is possible to align the direction of the magnetic flux penetrating the loop hole regions 14a, 14b, and 14c.

  For this reason, the directional characteristic of the directional coupler 10 can be improved.

  The second difference between the directional coupler 10 of the RF module 100 described in the first embodiment and the directional coupler 10 of the second embodiment is that the main line 11 is the uppermost layer and the lowermost layer. It is the point formed in the 2nd layer which is an intermediate | middle layer between.

  By forming the main line 11 in the intermediate layer in this way, the extension part 13a of the sub line 12 above the main line 11 and the extension part 13c of the sub line 12 below the main line 11 are mainly used. It becomes possible to superimpose on the track 11.

  For this reason, the directional coupler 10 according to the second embodiment can improve the degree of coupling by capacitive coupling as compared with the directional coupler 10 described in the first embodiment.

  In the second embodiment, the embodiment in which both the extending portions 13a and 13c are overlapped with the main line 11 has been described. However, the present invention is not limited to this. When a desired degree of coupling is obtained by superimposing either one of the extending part 13a or the extending part 13c on the main line 11, only one of them may be superposed. A modification of the second embodiment will be described.

  FIG. 7 is an enlarged cross-sectional view of a directional coupler portion built in a wiring board of an RF module which is a modification of the second embodiment, and FIG. 8 is a wiring of an RF module which is a modification of the second embodiment. It is a perspective view which shows the structure of the main line of the directional coupler part built in the board | substrate, and a subline.

  In FIG. 7 and FIG. 8, the extending portion 13 c arranged in the lowermost wiring layer of the sub-line 12 overlaps with the main line 11, but the extending portion 13 b arranged in the intermediate layer is connected to the main line 11. It is not superimposed. When arranged in this way, the degree of coupling due to capacitive coupling is lower than that of the directional coupler 10 shown in FIGS.

  However, in the directional coupler 10 shown in FIGS. 7 and 8, since the loop region 14c surrounded by the loop arranged in the lowermost layer of the sub-line 12 is expanded, the degree of coupling by inductive coupling is improved. Can do. In addition, depending on the application, it may be sufficient to obtain this degree of coupling property.

  As described above, when improvement in the degree of coupling characteristic by capacitive coupling is not required, the main line 11 is preferably formed on the surface of the uppermost insulating layer 3 of the wiring board 1 as shown in FIG. By forming the main line 11 on the surface of the uppermost insulating layer 3 of the wiring board 1, it is possible to reduce transmission loss of the transmission power wiring 2 (see FIG. 1).

  As described above, the directional coupler 10 according to the second embodiment has a coupling degree due to capacitive coupling by overlapping at least one of the extending portions 13a, 13b, and 13c with the main line 11. It becomes possible to improve. Moreover, a desired coupling degree characteristic can be obtained by adjusting the number of extending portions to be superimposed on the main line 11. For this reason, it becomes possible to improve the freedom degree in the characteristic design of a coupling degree characteristic.

  Further, since desired characteristics can be obtained even if the plane area occupied by the sub-line 12 is reduced, the directional coupler 10 can be reduced in size.

(Embodiment 3)
In the second embodiment, the case has been described in which the line widths of the surface wirings of the sub-lines formed over the three layers are all equal. However, in the third embodiment, the surface wiring has a different line width for each wiring layer. The embodiment to be formed will be described.

  FIG. 9 is an enlarged cross-sectional view of a directional coupler portion built in the wiring board of the RF module of the third embodiment, and FIG. 10 shows directional coupling built in the wiring board of the RF module of the third embodiment. FIG.

  The difference between the directional coupler 10 described in the second embodiment and the directional coupler 10 according to the third embodiment is that the surface wiring 13 constituting the sub line 12 as shown in FIG. 9 and FIG. The line width is different for each layer.

  More specifically, as shown in FIG. 10, the line widths of the extension portions 13 b of the sub-line 12 that overlap with the main line 11 are the extension portions 13 a and 13 c of the sub-line 12 that do not overlap with the main line 11. It is thicker than the line width.

  As described in the first embodiment, the degree of coupling by capacitive coupling is defined by the distance between the main line 11 and the extending portion and the plane area of the surfaces facing each other.

  Therefore, the coupling characteristic of the directional coupler 10 can be adjusted by configuring the surface wiring 13 constituting the sub line 12 so that the line width is different for each layer. That is, according to the third embodiment, the degree of freedom in the characteristic design of the directional coupler 10 can be improved.

  Moreover, since the degree of coupling can be improved by increasing the line width of the sub-line 12, the plane area occupied by the sub-line 12 can be reduced. For this reason, it becomes possible to reduce the size of the directional coupler 10.

(Embodiment 4)
In the first embodiment, the directional coupler in which the wiring layer on which the surface wiring of the sub line is formed has a three-layer structure has been described, but the number of layers of the wiring board is not limited thereto. For example, the sub line may be formed over two layers, or may be formed over four or more wiring layers.

  In the fourth embodiment, as an example of a directional coupler having a wiring structure other than a three-layer structure, a case where a directional coupler is built in a wiring board having two wiring layers will be described.

  FIG. 11 is an enlarged cross-sectional view of a directional coupler portion built in the wiring board of the RF module of the fourth embodiment, and FIG. 12 shows directional coupling built in the wiring board of the RF module of the fourth embodiment. FIG.

  The difference between the directional coupler 10 of the RF module 100 described in the first embodiment and the directional coupler 10 of the fourth embodiment is that the surface wiring of the sub-line 12 as shown in FIGS. 13 is a point formed over two layers.

  Thus, the directional coupler 10 can be thinned by making the subline 12 have a two-layer structure.

  By the way, when the wiring structure of the sub-line 12 is a two-layer structure, the degree of coupling characteristics is reduced as compared with the case where the sub-line 12 having a three-layer structure is used. However, by increasing the area of the loop hole regions 14a and 14b of the loop surrounded by the sub line 12, it is possible to suppress a decrease in the coupling characteristic.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiments of the invention. However, the present invention is not limited to the embodiments of the invention, and various modifications can be made without departing from the scope of the invention. Is possible.

  The present invention can be applied to a semiconductor device used as a high frequency circuit module and a directional coupler used as a power detector of the high frequency circuit module.

It is a top view which shows the structure principal part of RF module of Embodiment 1 of this invention. FIG. 2 is an equivalent circuit diagram of the RF module shown in FIG. 1. It is an expanded sectional view along the AA line shown in FIG. It is a perspective view which shows the structure of the main line of the directional coupler part of the RF module shown in FIG. 1, and a subline. It is sectional drawing to which the directional coupler part incorporated in the wiring board of RF module of Embodiment 2 of this invention was expanded. It is a perspective view which shows the structure of the main line of a directional coupler part built in the wiring board of RF module of Embodiment 2 of this invention, and a subline. It is sectional drawing to which the directional coupler part incorporated in the wiring board of RF module which is a modification of Embodiment 2 of this invention was expanded. It is a perspective view which shows the structure of the main line of a directional coupler part built in the wiring board of RF module which is a modification of Embodiment 2 of this invention, and a subline. It is sectional drawing to which the directional coupler part incorporated in the wiring board of RF module of Embodiment 3 of this invention was expanded. It is a perspective view which shows the structure of the main line of a directional coupler part built in the wiring board of RF module of Embodiment 3 of this invention, and a subline. It is sectional drawing to which the directional coupler part incorporated in the wiring board of RF module of Embodiment 4 of this invention was expanded. It is a perspective view which shows the structure of the main line of a directional coupler part built in the wiring board of RF module of Embodiment 4 of this invention, and a subline.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wiring board 2 Transmission power wiring 3 Insulating layer 4 Sealing resin 5 Termination resistance element 10 Directional coupler 11 Main line (1st wiring)
11a Input end 11b Output end 12 Sub line (second wiring)
12a Detection end 12b Termination 13 Surface wiring 13a, 13b, 13c Extension portions 14a, 14b, 14c Region 15 Via 16 direction (first direction)
17 direction (second direction)
20 Semiconductor chip (semiconductor element)
21 Transmission power output terminal 22 Power amplifier 23 Detector 24 Bias voltage adjustment circuit 25 Detection terminal 30 Antenna switch 31 Input terminal 40 Output matching circuit 50 Low-pass filter 100 RF module (semiconductor device)
101 Transmission input terminal 102 Antenna output terminal

Claims (7)

A wiring board having a plurality of laminated insulating layers, and a plurality of wiring layers in which wiring is formed in a desired pattern on the surface of each of the plurality of insulating layers;
A first wiring formed in a single wiring layer among the plurality of wiring layers;
A second wiring that is formed across the plurality of wiring layers and includes an extending portion that extends along the first wiring;
The first wiring does not have a bent portion,
The directional coupler according to claim 1, wherein the second wiring is formed so as to form a coil-shaped loop on one side surface side of the first wiring. A wiring board having a directional coupler, and a semiconductor element mounted on the wiring board,
The wiring board is
A plurality of laminated insulating layers;
A plurality of wiring layers in which wiring is formed in a desired pattern on the surface of each of the plurality of insulating layers;
The directional coupler is
A first wiring formed in a single wiring layer among the plurality of wiring layers;
A second wiring that is formed across the plurality of wiring layers and includes an extending portion that extends along the first wiring;
The first wiring does not have a bent portion,
The semiconductor device, wherein the second wiring is formed so as to form a coil-shaped loop on one side of the first wiring. The semiconductor device according to claim 2,
The first wiring has an input end and an output end,
The second wiring has a termination and a detection end,
The coil-shaped loop of the second wiring is such that, in the extending portion, the first direction from the termination side to the detection end is opposite to the second direction from the input end to the output end of the first wiring. A semiconductor device characterized by being arranged in a direction. The semiconductor device according to claim 3.
The second wiring is
A surface wiring that is formed on the surface of the plurality of insulating layers and has an extending portion that extends along the first wiring; and a bent portion that is bent to form the loop;
A conductive path electrically connecting the upper surface wiring and the lower surface wiring;
The semiconductor device according to claim 1, wherein the first region surrounded by the loop of the second wiring does not overlap with the first wiring. The semiconductor device according to claim 3.
The first wiring is formed in an arbitrary wiring layer located between the uppermost layer and the lowermost layer among the plurality of wiring layers. The semiconductor device according to claim 3.
A semiconductor device, wherein a terminal resistance element is connected to the terminal end side of the second wiring. The semiconductor device according to claim 3.
The semiconductor device according to claim 1, wherein the second wiring has a line width different for each of the plurality of wiring layers.

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