Patent Grant
6975271
1. Filed of the Invention
The present invention relates to an antenna switch module, an all-in-one communication module, a communication apparatus and a method for manufacturing the antenna switch module. For instance, it relates to antenna switch modules for high-frequency and high-power signals.
2. Related Art of the Invention
In recent years, there has been a demand for a portable telephone supporting a multi band capable of using a plurality of methods. The reason for this is an expanding user base of mobile communication such as portable telephones and globalization. For instance, there is a demand for a triple-band portable telephone using three communication methods of different frequency bands of ESGM (Enhanced-Global System for Mobile Communication) method mainly used in Europe, a DCS (Digital Cellular System) method increasingly used in conjunction with the expanding user base of portable telephones and a PCS (Personal Communication Services) method mainly used in the U.S.A. Furthermore, there is a demand for a quad-band portable telephone adding UMTS (Universal Mobile Telecommunication System) which implements next-generation high-speed communication.
For that reason, development is underway antenna switches using FET switches comprised of GaAs-field-effect transistors (hereafter, FETs) capable of easily supporting the trend toward multi band.
As shown in
The capacitor 17 is formed in the semiconductor chip by using the MIM capacitor for the following reason. To be more specific, if an impedance between the FET of the shunt circuit and the ground in the antenna switch circuit becomes high, a ground potential of the FET of the shunt circuit becomes high on operation and a high-frequency characteristic deteriorates. Thus, as shown in
The above-mentioned antenna switch in the prior art uses an MIM capacitor formed in the semiconductor chip as a capacitor for connecting an FET of a shunt circuit to a ground. The MIM capacitor is generally a parallel plate type capacitor sandwiching an insulator such as SiO2 or SiN of 0.2 to 0.3 μm thickness with a conductive material such as Au. Therefore, there is a problem that, if an electrostatic surge of 300V or so gets in from the outside, the capacitor connected to the FET of the shunt circuit is destroyed so that it no longer functions as the switch.
The present invention resolves the problem in the prior art, and an object thereof is to provide an antenna switch module, an all-in-one communication module, a communication apparatus and a method for manufacturing the antenna switch module, wherein the capacitor is not destroyed and a high-frequency characteristic does not deteriorate even in the case where a high-voltage signal such as the electrostatic surge flows in.
The 1st aspect of the present invention is an antenna switch module comprising a switch circuit for switching between transmitting and/or receiving of a signal between an antenna and a transmitting portion and/or a receiving portion and having a shunt circuit, wherein a capacitor of the shunt circuit of said switch circuit is provided to a dielectric layered body, and remaining elements of said switch circuit are provided to a semiconductor chip mounted on said dielectric layered body.
The 2nd aspect of the present invention is the antenna switch module according to the 1st aspect of the present invention, wherein said semiconductor chip is mounted face down on a top surface of said dielectric layered body.
The 3rd aspect of the present invention is the antenna switch module according to the 2nd aspect of the present invention, wherein an electrical connection between said semiconductor chip and said dielectric layered body is made in a surface of said semiconductor chip if projectively viewed from the top surface of said dielectric layered body.
The 4th aspect of the present invention is the antenna switch module according to the 1st aspect of the present invention, wherein said semiconductor chip is mounted by wire bonding.
The 5th aspect of the present invention is the antenna switch module according to the 2nd or the 4th aspects of the present invention, wherein said dielectric layered body has a plurality of dielectric sheets including a first dielectric sheet on which a first electrode pattern connected to a ground potential is formed and a second dielectric sheet on which a second electrode pattern placed opposite said first electrode pattern is formed, and said capacitor is formed between said first electrode pattern and said second electrode pattern.
The 6th aspect of the present invention is the antenna switch module according to the 5th aspect of the present invention, wherein said first electrode pattern is provided closer to said semiconductor chip than said second electrode pattern in said dielectric layered body.
The 7th aspect of the present invention is the antenna switch module according to the 5th aspect of the present invention, wherein said second electrode pattern is provided closer to said semiconductor chip than said first electrode pattern in said dielectric layered body.
The 8th aspect of the present invention is the antenna switch module according to the 2nd or the 4th aspects of the present invention, wherein said first dielectric sheet is placed on said dielectric layered body except its top layer, and said first electrode pattern has a shape for including at least the entire contours of said semiconductor chip if projectively viewed from the top surface of said dielectric layered body.
The 9th aspect of the present invention is the antenna switch module according to the 8th aspect of the present invention, wherein, on said dielectric layered body, a third electrode pattern formed on a third dielectric sheet placed on said first dielectric sheet overlapping said first electrode pattern if projectively viewed from the top surface is connected to a fourth electrode pattern formed on a fourth dielectric sheet placed under said first dielectric sheet through an opening formed on said first electrode pattern so as not to short the ground potential.
The 10th aspect of the present invention is the antenna switch module according to the 7th aspect of the present invention, wherein said third electrode pattern is connected to an arbitrary terminal of said semiconductor chip, and said fourth electrode pattern is the same as said second electrode pattern.
The 11th aspect of the present invention is the antenna switch module according to the 1st aspect of the present invention, wherein said switch circuit has one pair or a plurality of pairs of a first field-effect transistor and a second field-effect transistor, and each of said pairs has a drain terminal of said first field-effect transistor connected to a source terminal of said second field-effect transistor and the drain terminal of said second field-effect transistor connected to a ground potential via said capacitor.
The 12th aspect of the present invention is the antenna switch module according to the 1st aspect of the present invention, wherein said switch circuit has one pair or a plurality of pairs of a first field-effect transistor and a second field-effect transistor, and each of said pairs has a source terminal of said first field-effect transistor connected to a drain terminal of said second field-effect transistor and the source terminal of said second field-effect transistor connected to a ground via said capacitor.
The 13th aspect of the present invention is the antenna switch module according to the 5th aspect of the present invention, wherein a combination of electrode patterns of certain dielectric sheets of said plurality of dielectric sheets forming said dielectric layered body forms one high-frequency filter or a plurality of high-frequency filters.
The 14th aspect of the present invention is the antenna switch module according to the 13th aspect of the present invention, wherein said first electrode pattern has a shape for including all the electrode patterns of said certain dielectric sheets forming said high-frequency filters if projectively viewed from the top surface of said dielectric layered body.
The 15th aspect of the present invention is an all-in-one communication module comprising:
the antenna switch module according to the 1st aspect of the present invention;
a low-pass filter of said transmitting portion provided in said dielectric layered body; and
a power amplifier for supplying a transmitting signal to said low-pass filter provided on said dielectric layered body.
The 16th aspect of the present invention is the all-in-one communication module according to the 15th aspect of the present invention, further comprising:
a band pass filter of said receiving portion provided in said dielectric layered body; and
a voltage-controlled oscillator for supplying a transmitting signal to said power amplifier on the transmitting side provided on said dielectric layered body.
The 17th aspect of the present invention is a communication apparatus comprising:
the antenna switch module according to the 1st aspect of the present invention;
an antenna connected to said antenna switch module;
the transmitting portion for supplying the transmitting signal to said antenna switch module; and
the receiving portion.
The 18th aspect of the present invention is a communication apparatus comprising:
the all-in-one communication module according to any one of the 15th and the 16th aspects of the present invention; and
an antenna connected to said low-pass filter and/or said band pass filter.
The 19th aspect of the present invention is a method for manufacturing an antenna switch module comprising a switch circuit for switching between transmitting and receiving of a signal between an antenna and a transmitting portion or a receiving portion and having a shunt circuit, wherein the method has the steps of:
placing a capacitor of the shunt circuit of said switch circuit on a dielectric layered body; and
placing remaining elements of said switch circuit on a semiconductor chip mounted on said dielectric layered body.
The 20th aspect of the present invention is the method for manufacturing the antenna switch module according to the 19th aspect of the present invention, wherein said semiconductor chip is mounted face down on a top surface of said dielectric layered body.
The 21st aspect of the present invention is the method for manufacturing the antenna switch module according to the 19th or the 20th aspects of the present invention, wherein said dielectric layered body is manufactured by laminating a plurality of dielectric sheets including a first dielectric sheet on which a first electrode pattern connected to a ground potential is formed and a second dielectric sheet on which a second electrode pattern placed opposite said first electrode pattern is formed, and said capacitor is formed between said first electrode pattern and said second electrode pattern.
Hereafter, preferred embodiments of the present invention will be described based on the attached drawings.
(First Embodiment)
An example of a method for manufacturing the dielectric layered body 31 will be described. The dielectric layered body may be manufactured by using a dielectric material of an A1-Mg—Si—Gd—O system. First, a plurality of via holes are made by using mechanical punching or a laser process on green sheets made by molding slurry obtained by mixing the ceramic powder with an organic binder and an organic solvent. Next, a conductive paste of which main component is Ag (or a conductive material of low resistance such as Au or Cu) is filled in the via holes for interlayer-connecting wiring patterns formed on the green sheets. And the wiring patterns are formed on the green sheets by a screen printing method so as to form a stripline electrode pattern and a capacitor electrode pattern.
Next, a plurality of green sheets obtained as above are correctly aligned, laminated in order and warmed and pressurized under predetermined conditions so as to obtain an integrated dielectric layered body. The dielectric layered body is dried and is then burned at 400 to 500 degrees C. in a burning furnace in an oxidized atmosphere so that the organic binders in the green sheets are burned out. Next, a final dielectric layered body 31 is obtained by burning the dielectric layered body in a temperature range of approximately 850 to 950 degrees C. in the ordinary air in the case of using the powder of Au or Ag as the main component of the conductive material or in an inactive gas or a reducing atmosphere in the case of using the powder of Cu.
The electrode patterns formed in the dielectric layers will now be described.
In
The stripline electrode patterns Lp1 to Lp17 and the land electrode pattern for dies bond Dp1 have via hole electrodes punched thereon respectively. On the top surface of the dielectric layers L2, an earthed electrode pattern Gp1 is formed by printing, which has larger area than the land electrode pattern for dies bond Dp1 formed on the top surface of the dielectric layer L1. On the earthed electrode pattern Gp1, spacer patterns Sp1 to Sp7 are formed in its electrode surface for the sake of punching the via hole electrodes not shorting the earthed electrode pattern Gp1. The land electrode pattern for dies bond Dp1 of the dielectric layer L1 is connected to the earthed electrode pattern Gp1 of a dielectric layers L2 via the plurality of via hole electrodes.
In
A description will be given by using
The spacer pattern Sp1 has a shape of a string of circular spacer patterns with a 300 μm radius centering on the via land electrode pattern. The capacitor electrode pattern Cp4 is placed opposite the earthed electrode pattern Gp1 except the area projectively overlapping the spacer pattern Sp1. Thus, a capacitor C4 is formed by the capacitor electrode pattern Cp4 and the earthed electrode pattern Gp1. Likewise, capacitors C1 to C6 are formed by the capacitor electrode patterns Cp1 to Cp6 and the opposite earthed electrode pattern Gp1 respectively.
Here, the dielectric layer L2 is an example of the first dielectric sheet of the present invention, and the earthed electrode pattern Gp1 formed on the dielectric layer L2 is an example of the first electrode pattern of the present invention. The dielectric layer L3 is an example of the second dielectric sheet of the present invention, and the capacitor electrode patterns Cp1 to Cp6 formed on the dielectric layer L3 are an example of the second electrode pattern of the present invention. And the capacitors C1 to C6 are an example of the capacitors of a shunt circuit provided to the dielectric layered body of the present invention. And the spacer patterns Sp1 to Sp7 are an example of openings formed on the first electrode pattern of the present invention.
In
On the top surface of the dielectric layer L4, there are the wiring electrode patterns necessary for connecting the electrode pattern formed on the top surface of the dielectric layer L1 to the under surface electrode patterns T1 formed by printing. The earthed electrode pattern Gp2 has the via hole electrodes punched thereon, and the via hole electrodes are connected to the under surface ground electrode patterns TG respectively. The earthed electrode pattern Gp2 is connected to the earthed electrode pattern Gp1 formed on the top surface of the dielectric layer L2 via the plurality of via hole electrodes.
The RF signal under surface electrode patterns TR are connected to the stripline electrode patterns Lp2, Lp4, Lp9, Lp11, Lp13, Lp15 and Lp17 formed on the top surface of the dielectric layer L1 via the wiring electrode patterns formed on the dielectric layers constituting the via hole electrodes and the dielectric layered body 31 respectively. And the control signal under surface electrode patterns TS are connected to the stripline electrode patterns Lp5 to Lp8 formed on the top surface of the dielectric layer L1 via the via hole electrodes and the wiring electrode patterns formed on the dielectric layers constituting the dielectric layered body 31 respectively.
A circuit of the portion enclosed by the dashed line in
An SPST switch circuit is comprised of the SPST switch 10, a second DC cut capacitor 18 and a third DC cut capacitor 19 both of which are connected to the outside of the SPST switch 10. And a first high-frequency signal input-output terminal P1 of the SPST switch 10 is connected to an antenna 13 via the second DC cut capacitor 18, a second high-frequency signal input-output terminal P2 is connected to a receiving portion 20 via the third DC cut capacitor 19, and a third high-frequency signal input-output terminal P3 is connected to the ground.
In the SPST switch 10, the first high-frequency signal input-output terminal P1 is connected to a drain terminal of a first FET 15, and a source terminal of the first FET 15 is connected to the second high-frequency signal input-output terminal P2. The source terminal of the first FET 15 is connected to the drain terminal of a second FET 16, and the source terminal of the second FET 16 is connected to the third high-frequency signal input-output terminal P3 via the first DC cut capacitor 17. Here, the second FET 16 and first DC cut capacitor 17, and the second high-frequency signal input-output terminal P2, third high-frequency signal input-output terminal P3 and a gate terminal G12 connected thereto form the shunt circuit of the SPST switch 10.
The operation of the SPST switch 10 constituted as above will be described below.
Bias voltages of +VG [V], 0 [V] to the ground are applied to a gate terminal G11 of the first FET 15 and a gate terminal G12 of the second FET 16 respectively. In this case, a potential to the ground at the source terminal of the first FET 15 (hereafter, referred to as VS1) and the potential to the ground at the drain terminal of the second FET 16 (hereafter, referred to as VD2) are the same so that a potential relationship of these terminals is as in a formula 1. Here, VG1 and VG2 are the potentials to the ground at the gate terminals of the first FET 15 and second FET 16 respectively.
+VG=VG1>VS1=VD2>VG2=0[V] (Formula 1)
When the first FET 15 is seen on such a bias condition, it is a forward bias between the gate and source terminals. And when the second FET 16 is seen, it is a backward bias between the drain and gate terminals. As the third DC cut capacitor 19 is connected to the second high-frequency signal input-output terminal P2, it is considered that a forward current and a backward current thereof are the same, and the relationship between a potential difference VG1−VS1 between the gate and source terminals of the first FET 15 and the potential difference VD2−VG2 between the drain and gate terminals of the second FET 16 is as in a formula 2.
VG1−VS1<<VD2−VG2 (Formula 2)
As it is the backward bias between the drain and gate terminals of the second FET 16, the running current is very little. Therefore, the potential VS1 of the source terminal of the first FET 15 and the potential VD2 of the drain terminal of the second FET 16 are as in a formula 3, and so they are in the relationship in a formula 4.
VS1=VD2 (Formula 3)
VD2≈VG (Formula 4)
Consequently, the first FET 15 is in an on state and the second FET 16 is in an off state so that the signals inputted from the antenna 13 are outputted to the receiving portion 20.
Likewise, in the case of applying the bias voltages of 0 [V], +VG [V] to the gate terminal G11 of the first FET 15 and the gate terminal G12 of the second FET 16 respectively, the first FET 15 is put in the off state and the second FET 16 is put in the on state. Therefore, the signals inputted from the antenna 13 are mostly attenuated at the first FET 15, and the few signals passing through it flow to the ground via the second FET 16 so that there is no signal flowing from the antenna 13 to the receiving portion 20.
Therefore, it is possible, as described above, to control the potential VG1 of the gate terminal G11 of the first FET 15 and the potential VG2 of the gate terminal G12 of the second FET 16 so as to have the SPST switch 10 function as the antenna switch.
In the case where a high-voltage signal such as an electrostatic surge flows in from the outside via the antenna 13 and so on, the first DC cut capacitor 17 of the SPST switch 10 plays a role of a surge-absorbing capacitor so as to protect the SPST switch 10.
The above configuration and operation of the antenna switch circuit were described by taking as an example the case where the electronics device receives the signals from the antenna. However, the configuration and operation of the antenna switch circuit are the same as to the electronics device for transmitting the signals from the antenna. In the case of transmitting the signals from the antenna, the second high-frequency signal input-output terminal P2 is connected to a transmitting portion instead of the receiving portion 20 via the third DC cut capacitor 19 in
The antenna switch module 30 according to the first embodiment is the portion enclosed by the dashed line in
And all the remaining elements of each SPST switch 10, that is all the circuit portions such as the first FET 15 and second FET 16 except the DC cut capacitor 17 are provided to the switch semiconductor chip 32 and logic semiconductor chip 33. And terminals P4 after the second high-frequency signal input-output terminals P2 go through the third DC cut capacitors 19 are connected to different receiving portion or transmitting portion respectively.
It is possible, as to each route, to control a bias potential to be applied to the gate terminal G11 of the first FET 15 and the gate terminal G12 of the second FET 16 of the SPST switch 10 so as to switch the route to the receiving portion or transmitting portion to be connected to the antenna 13 and have the antenna switch module 30 according to the first embodiment function as an SP6T antenna switch module.
The capacitors C1 to C6 formed inside the dielectric layered body 31 function as the first DC cut capacitor 17 constituting the shunt circuit of the antenna switch module 30 according to the first embodiment.
Dielectric film thickness of the capacitors C1 to C6 formed inside the dielectric layered body 31 is 12.5 μm or so, which is thicker than the film thickness of 0.3 μm or so of the capacitors formed inside the semiconductor chip manufactured by using a GaAs material of the past. Therefore, there is an experimental result that electrostatic surge withstand pressure improves by two to three times in comparison with the antenna switch module in the prior art. In this case, the electrostatic surge withstand pressure in the antenna switch module 30 according to the first embodiment is determined by the withstand pressure of the FETs instead of the withstand pressure of the capacitors.
According to this embodiment, the FETs of the SPST switch are electrically connected to the capacitors by using the via hole electrodes and utilizing a thickness direction of the dielectric layered body. As a result of having such a configuration, a wiring Ls1 shown in
The antenna switch module 30 according to the first embodiment has the earthed electrode pattern Gp1 of large area formed on the dielectric layer L2 which is the second electrode layer from the top of the dielectric layered body 31. And the first DC cut capacitor 17 is formed by including the earthed electrode pattern Gp1 of the large area inside the dielectric layered body 31.
Furthermore, an SPnT (n: an arbitrary natural number) switch such as the SPST switch of this embodiment requires n pieces of the capacitors to be used for the shunt circuit. However, it is possible, by taking the above configuration, to sandwich the capacitors with two ground electrodes of the earthed electrode patterns Gp1 and Gp2 so as to render electrode area small. To be more specific, in the dielectric layered body 31, the first dielectric layer L1 is set to have a thicker film thickness than other layers in order to keep its strength. Therefore, it is more advantageous, for the sake of rendering the area small, to form capacitor electrodes between the ground electrodes of the first dielectric layer L1 and the third dielectric layer L3 rather than to form the capacitors with the ground electrodes, land electrode pattern for dies bond Dp1 and so on.
Furthermore, the dies bond electrode must have wire-bonded electrodes placed around it, and so it is limited area-wise by the ground electrode of the first dielectric layer L1.
Therefore, it is easier, by forming the capacitors with the ground electrode of the first dielectric layer L1, to form a large number of capacitors of large area and obtain a necessary capacity.
Furthermore, the earthed electrode pattern Gp1 is connected to a plurality of under surface ground electrode patterns TG by a plurality of via hole electrodes so that it is possible to curb the parasitic inductance component between the second FET 16 of a FET switch and the ground. Therefore, it is possible to realize the reduction in the impedance between the second FET 16 of the FET switch and the ground on a switch operation, and the antenna switch module 30 according to the first embodiment can improve the high-frequency characteristic.
The stripline electrode patterns on the dielectric layer L1 are connected to the electrode patterns such as the capacitor electrode patterns Cp1 to Cp6 on the dielectric layer L3 via the via hole electrodes provided to the spacer patterns Sp1 to Sp7 formed inside the earthed electrode pattern Gp1. Thus, it is possible to render line length shorter than the case of connecting via the via hole electrodes provided outside the earthed electrode patterns in the prior art so as to reduce the impedance. To be more specific, this configuration also has an effect of reducing the impedance between the second FET 16 of the FET switch and the ground on the switch operation, and so the antenna switch module 30 according to the first embodiment can further improve the high-frequency characteristic.
Thus, as for the antenna switch module according to the first embodiment, the capacitors are not destroyed even in the case where the high-voltage signal such as the electrostatic surge flows in, and it can present the ground potential of the FET of the shunt circuit from rising on the switch operation. Therefore, it is possible to provide the antenna switch module excellent in the high-frequency characteristic.
The switch semiconductor chip 32 and logic semiconductor chip 33 are dies-bond-mounted on the top surface of the dielectric layered body and have the earthed electrode pattern Gp1 which is larger than the land electrode pattern for dies bond Dp1. Therefore, the ground potentials of the switch semiconductor chip 32 and logic semiconductor chip 33 become stable. For this reason, it is possible to provide the antenna switch module of a stable switch operation.
As for the FET switch of the past including the first DC cut capacitor 17 inside a semiconductor chip 46 in FIG. 14, a size of the MIM capacitor for functioning as the first DC cut capacitor 17 is 100 μm square or so. In the case of using the antenna switch module 30 according to the first embodiment, it is possible to eliminate the MIM capacitor from the inside of the semiconductor chip of the past so as to reduce the semiconductor chip size. The switch semiconductor chip in which the MIM capacitor was placed in the prior art uses expensive semiconductors such as GaAs, and so the number of the semiconductor chips producible from one wafer can be increased by reducing the chip size so as to allow reduction in semiconductor chip costs.
According to the first embodiment, the dielectric material of an A1-Mg—Si—Gd—O system is used as the material of the dielectric layered body. However, it is possible to obtain the same effect by using another dielectric material of a higher dielectric constant. In this case, it is possible to reduce the area occupied by the capacitors placed inside dielectric layered body so as to realize miniaturization of the antenna switch module.
The same effect can also be obtained in the case where the drain terminal and source terminal of the first FET 15 and the second FET 16 are connected contrary to the first embodiment.
According to the first embodiment, the dielectric layered body 31 is formed by five layers of the dielectric layers L1 to L5. However, the number of the dielectric layers forming the dielectric layered body is not limited, and so it may be either more or less than the five layers.
(Second Embodiment)
The antenna switch module according to a second embodiment will be described by referring to the drawings.
The dielectric layered body 51 has a high-frequency filter 37 formed by an internal electrode pattern 35 and a via hole electrode 36 formed by printing the high-frequency filter 37 being placed, below an earthed electrode pattern Gp5 and capacitor electrode patterns Cp11 to Cp16. The high-frequency filter 37 referred to here is a low-pass filter connected between the antenna switch and the transmitting portion, for instance. Capacitors C11 to C16 to be connected to a shunt of an FET switch circuit are implemented by the earthed electrode pattern Gp5 and capacitor electrode patterns Cp11 to Cp16.
And a switch semiconductor chip 52 and a logic semiconductor chip 53 having an FET switch function are mounted face down on the top surface of the dielectric layered body 51. In this case, the switch semiconductor chip 52 and logic semiconductor chip 53 are electrically connected to the dielectric layered body 51 by flip chip mounting using a bump inside the surface of each semiconductor chip if projectively viewed from the top surface of the dielectric layered body 51.
The earthed electrode pattern Gp5 of the dielectric layer L102 is formed by printing. And the electrode patterns such as inductor electrodes, capacitor electrodes and stripline electrodes formed by combining the electrode patterns of the dielectric layers lower than the dielectric layer L103 constitute the high-frequency filter 37. The area of the earthed electrode pattern Gp5 is large enough to cover the high-frequency filter area 55 in which the electrode patterns for constituting the high-frequency filter are formed.
The spacer patterns for punching the via hole electrodes not shorting the earthed electrode pattern Gp5 are formed in the electrode surface of the earthed electrode pattern Gp5 formed on the dielectric layer L102. The dielectric layer L101 has the electrode patterns for mounting the switch semiconductor chip 52 and logic semiconductor chip 53 and the stripline electrode patterns comprising via land electrodes formed on the top surface thereof.
The stripline electrode patterns are connected to the capacitor electrode patterns Cp11 to Cp16 formed on the dielectric layer L103 and the internal electrode pattern 35 for forming the high-frequency filter 37 and so on placed in the dielectric layer L103 or in the dielectric layer lower than that or the under surface electrode patterns formed on the under surface of the dielectric layered body 51. And the via hole electrodes for connecting the stripline electrode patterns formed on the dielectric layer L101 to the electrode patterns formed in the layers lower than the dielectric layer L102 are punched on the spacer patterns formed in the electrode surface of the earthed electrode pattern Gp5 on the dielectric layer L102.
A description will be given by using
The spacer pattern Sp10 has a shape of the string of the circular spacer patterns with the 300 μm radius centering on the via land electrode pattern. The capacitor electrode pattern Cp11 is placed opposite the earthed electrode pattern Gp5 except the area projectively overlapping the spacer pattern Sp10. Thus, a capacitor C11 is formed by the capacitor electrode pattern Cp11 and the earthed electrode pattern Gp5. Likewise, capacitors C12 to C16 are formed by the capacitor electrode patterns Cp12 to Cp16 and the opposite earthed electrode pattern Gp5 respectively.
The circuit of the portion enclosed by an alternate long and short dashed line in
An SPST switch circuit is comprised of the SPST switch 22, and a second DC cut capacitor 48 and a third DC cut capacitor 49 both of which are connected to the outside of the SPST switch 22. And a first high-frequency signal input-output terminal P11 of the SPST switch 22 is connected to an antenna 23 via the second DC cut capacitor 48, a second high-frequency signal input-output terminal P12 is connected to a receiving portion 21 via the third DC cut capacitor 49, and a third high-frequency signal input-output terminal P13 is connected to the ground. The SPST switch 22 is comprised of a first FET group 24 consisting of FETs 24a, 24b, 24c and 24d connected in parallel in four stages, a second FET group 25 consisting of FET 25a, 25b, 25c and 25d connected in parallel in four stages likewise and a first DC cut capacitor 47.
The first high-frequency signal input-output terminal P11 is connected to the drain terminal of a FET 24a on the first stage of the first FET group 24, and the source terminal of the FET 24a on the first stage of the first FET group is connected to the drain terminal of the second FET 24b on the second stage of the first FET group 24. The source terminal of the FET 24b on the second stage of the first FET group 24 is connected to the drain terminal of the FET 24c on the third stage of the first FET group 24, and the source terminal of the FET 24c on the third stage of the first FET group 24 is connected to the drain terminal of the FET 24d on the fourth stage of the first FET group 24. And the source terminal of the FET 24d on the fourth stage of the first FET group 24 is connected to the second high-frequency signal input-output terminal P12. The source terminal of the FET 24d on the forth stage of the first FET group 24 is connected to the drain terminal of the FET 25a on the first stage of the second FET group 25. The second FET group 25 is connected in parallel as with the first FET group 24, and the source terminal of the FET 25d on the fourth stage of the second FET group 25 is connected to the third high-frequency signal input-output terminal P13 via the first DC cut capacitor 47.
The operation of the SPST switch 22 constituted as above will be described below.
The gate terminals of the FETs 24a, 24b, 24c and 24d forming the first FET group 24 are mutually connected, and the gate terminals of the FETs 25a, 25b, 25c and 25d forming the second FET group 25 are also mutually connected likewise. To be more specific, the same bias voltage is applied to all the gate terminals of the FETs 24a, 24b, 24c and 24d forming the first FET group 24, and likewise, the same bias voltage is applied to all the gate terminals of the FETs 25a, 25b, 25c and 25d forming the second FET group 25. Therefore, it is possible to consider the operation of the antenna switch module of the second embodiment as the one in which the first FET 15 and the second FET 16 of the first embodiment shown in
In the case of applying the bias voltages of +VG [V] 0 [V] to a gate terminal G21 of the first FET group 24 and a gate terminal G22 of the second FET group 25 respectively, the first FET group 24 is put in the on state and the second FET group 25 is put in the off state. Therefore, the signals inputted from the antenna 23 are outputted to the receiving portion 21.
Inversely, in the case of applying the bias voltages of 0 [V], +VG [V] to the gate terminal G21 of the first FET group 24 and the gate terminal G22 of the second FET group 25 respectively, the first FET group 24 is put in the off state and the second FET group 25 is put in the on state. Therefore, the signals inputted from the antenna 23 are mostly attenuated in the first FET group 24, and the few signals passing through it flow to the ground via the second FET group 25 so that there is no signal flowing from the antenna 23 to the receiving portion 21.
In the case where the high-voltage signal such as the electrostatic surge flows in from the outside via the antenna 23, the first DC cut capacitor 47 plays a role of the surge-absorbing capacitor so as to protect the SPST switch 22.
The above configuration and operation of the antenna switch circuit were described by taking as an example the case where the electronics device receives the signals from the antenna. However, the configuration and operation of the antenna switch circuit are the same as to the electronics device for transmitting the signals from the antenna. In the case of transmitting the signals from the antenna, the second high-frequency signal input-output terminal P12 is connected to the transmitting portion instead of the receiving portion 21 via the third DC cut capacitor 49 in
The antenna switch module 50 according to the second embodiment is the antenna switch module wherein six SPST switches 22 shown in
The capacitors C11 to C16 formed inside the dielectric layered body 51 function as the first DC cut capacitor 47 of the antenna switch module 50 according to the second embodiment. As with the antenna switch module 30 according to the first embodiment, it is possible, by using the capacitors C11 to C16 formed inside the dielectric layered body 51 as the first DC cut capacitor 47, to improve the electrostatic surge withstand pressure of the antenna switch module 50 according to the second embodiment by two to three times in comparison with the antenna switch module in the prior art.
As shown in
Therefore, it is possible to curb the parasitic inductance component in the line length connecting the second FET group 25 of the FET switch to the ground so as to reduce the impedance between the second FET group 25 of the FET switch and the ground on the switch operation and realize the improvement in the high-frequency characteristic.
Thus, according to the antenna switch module 50 of the second embodiment, it is possible to provide the antenna switch module excellent in the high-frequency characteristic, wherein the capacitors are not destroyed even in the case where the high-voltage signal such as the electrostatic surge flows in, and it functions as the switch and further keeps the ground potential of the FET of the shunt from rising on the switch operation.
As shown in
Furthermore, in order to prevent the capacitor electrode patterns Cp11 to Cp16 from extending off the area covered by the earthed electrode pattern Gp5 due to the lamination drift, the capacitor electrode patterns Cp11 to Cp16 are placed 50 μm or so inside from a surface position of the earthed electrode pattern Gp5 as shown in
It is also possible to shield electromagnetic waves generated by the switch semiconductor chip 52 and the high-frequency filter 37 with the earthed electrode pattern Gp5 so as to obtain a desired high-frequency characteristic from the switch semiconductor chip 52 and the high-frequency filter 37.
As the high-frequency filter 37 is formed by combining the dielectric layers lower than the earthed electrode pattern Gp5 while sandwiching the capacitor electrode patterns Cp11 to Cp16, it is also possible to reduce a stray capacitance generated between the earthed electrode pattern Gp5 and the high-frequency filter 37, in particular, the stripline electrode pattern for implementing the inductor. Therefore, the high-frequency filter 37 allows improvement in the high-frequency characteristic.
As the stripline electrode patterns on the dielectric layer L101 are connected to the electrode patterns on the dielectric layer L103 and lower layers via the via hole electrodes provided to the spacer patterns formed inside the earthed electrode pattern Gp5, it is possible to shorten the line length of the stripline electrodes on the top surface of the dielectric layer L101. If the line length of the stripline electrodes on the top surface of the dielectric layer L101 is shortened, it is possible to reduce the impedance between the FET of the shunt of the FET switch circuit and the ground in conjunction therewith so as to further improve the high-frequency characteristic.
According to the second embodiment, it is possible to obtain the same effect even if the high-frequency filter 37 formed in the dielectric layered body 51 is not the low-pass filter but the high-pass filter.
According to the second embodiment, it is possible to obtain the same effect, without being influenced by any other circuit configuration such as a resistance connected to the gate terminal, in the case of the circuit configuration wherein the FET switch has the FET in the shunt and the capacitor between the FET and the ground.
According to the second embodiment, one FET group is the FET switch comprised of the FETs connected in parallel in four stages. However, the FETs constituting one FET group is not limited to the four stages, but it is possible to obtain the same effect no matter how many stages the FETs constituting one FET group are in.
It is also possible to obtain the same effect even if the drain and source terminals of the FETs of the first FET group 24 and the second FET group 25 are connected inversely with the second embodiment respectively.
Both the embodiments defined that the antenna switch module has the configuration of the SP6T switch. However, it is possible to obtain the same effect even in the case of other configurations such as the SPST, SPDT, SP4T and SP7T.
According to the second embodiment, the electrical connections among the switch semiconductor chip 52, logic semiconductor chip 53 and dielectric layered body 51 are made inside the surface of each semiconductor chip if projectively viewed from the top surface of the dielectric layered body 51. However, it is also possible, as shown in
The switch semiconductor chip for constituting the antenna switch module is not limited to the semiconductor chip using GaAs. And the logic semiconductor chip for controlling the operation of the switch semiconductor chip is not limited to the semiconductor chip using Si. It is also possible to obtain the same effect even in the case of the antenna switch module using a single semiconductor chip instead of the one comprised of a plurality of semiconductor chips as shown in the embodiments.
As described in the description of the operation examples of the embodiments, the antenna switch module of the present invention can be used for the communication apparatus comprising a plurality of receiving portions or transmitting portions.
Here,
Furthermore, as shown in
Furthermore, as shown in
As is apparent from the above description, the present invention has the effect that the capacitor is not destroyed and the high-frequency characteristic does not deteriorate even in the case where the high-voltage signal such as the electrostatic surge flows in.
The antenna switch module, all-in-one communication module, communication apparatus and method for manufacturing the antenna switch module according to the present invention have the effect that the capacitor is not destroyed and the high-frequency characteristic does not deteriorate even in the case where the high-voltage signal such as the electrostatic surge flows in, and are useful as the antenna switch module for high-frequency and high-power signals and applied products thereof for instance.
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