RF POWER MODULE

Abstract

A technique is provided for achieving reduction in size of an electronic device with a power amplifier circuit, while enhancing the performance of the electronic device. An RF power module for a mobile communication device includes first and second semiconductor chips, a passive component, and first and second integrated passive components, which are mounted over a wiring board. In the first semiconductor chip, MISFET elements constituting power amplifier circuits for the GSM 900 and for the DCS 1800 are formed, and a control circuit is also formed. In the first integrated passive component, a low pass filter circuit for the GSM 900 is formed, and in the second integrated passive component, a low pass filter circuit for the DCS 1800 is formed. In the second semiconductor chip, antenna switch circuits for the GSM 900 and DCS 1800 are formed. Over the upper surface of the wiring board, the second semiconductor chip is disposed next to the first semiconductor chip between the integrated passive components.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a circuit block diagram of amplifier circuits constituting an RF power module according to one embodiment of the invention;

FIG. 2 is a circuit diagram showing an example of a circuit structure of a low pass filter;

FIG. 3 is an explanatory diagram of an example of a digital cellular phone system using the RF power module of the embodiment of the invention;

FIG. 4 is a circuit diagram showing an example of a circuit structure of a switch circuit;

FIG. 5 is a circuit diagram of a HEMT element used in the switch circuit of FIG. 4,

FIG. 6 is an equivalent circuit diagram of the HEMT element of FIG. 5 when it is turned on;

FIG. 7 is an equivalent circuit diagram of the HEMT element of FIG. 5 when it is turned off;

FIG. 8 is a circuit diagram showing an example of another circuit structure of the switch circuit;

FIG. 9 is a top view showing a structure of the RF power module according to the embodiment;

FIG. 10 is a sectional view of the RF power module according to the embodiment;

FIG. 11 is a sectional view of a main part of a semiconductor chip when a semiconductor amplification element is formed of a LDMOSFET;

FIG. 12 is a sectional view of a main part of the semiconductor chip when the switch circuit is formed using a HEMT element;

FIG. 13 is a plan view of a main part of the semiconductor chip of FIG. 12;

FIG. 14 is a sectional view showing a main part of a manufacturing step of an integrated passive component used in the RF power module of the embodiment;

FIG. 15 is a sectional view showing a main part of a manufacturing step of the integrated passive component, following the step of FIG. 14;

FIG. 16 is a sectional view showing a main part of a manufacturing step of the integrated passive component, following the step of FIG. 15;

FIG. 17 is a sectional view showing a main part of a manufacturing step of the integrated passive component, following the step of FIG. 16;

FIG. 18 is a sectional view showing a main part of a manufacturing step of the integrated passive component, following the step of FIG. 17;

FIG. 19 is a sectional view showing a main part of a manufacturing step of the integrated passive component, following the step of FIG. 18;

FIG. 20 is a sectional view of a manufacturing step of the RF power module of the embodiment;

FIG. 21 is a sectional view showing a manufacturing step of the RF power module, following the step of FIG. 20.

FIG. 22 is a sectional view showing a manufacturing step of the RF power module, following the step of FIG. 21.

FIG. 23 is a sectional view showing a manufacturing step of the RF power module, following the step of FIG. 22.

FIG. 24 is a schematic sectional view of a wiring board in a comparative example, which incorporates therein a low pass filter;

FIG. 25 is a top perspective drawing of a RF power module 1 according to one preferred embodiment of the invention;

FIG. 26 is a main plan view showing the vicinity of a semiconductor chip in the RF power module of the embodiment;

FIG. 27 is a main plan view showing the vicinity of a semiconductor chip in an RF power module of a comparative example;

FIG. 28 is a main plan view of the RF power module of the embodiment;

FIG. 29 is a plan view of the integrated passive component;

FIG. 30 is a main top view of the wiring board before mounting the integrated passive component;

FIG. 31 is a main top view of the wiring board before mounting the integrated passive component;

FIG. 32 is a sectional view of a main part of the wiring board before mounting the integrated passive component;

FIG. 33 is a sectional view showing a main part of a state in which the integrated passive component is mounted over the upper surface of the wiring board; and

FIG. 34 is a main plan view showing a main part of a case where the position of the integrated passive component deviates from a predetermined position.

Claims

1. An electronic device including a power amplifier circuit and a switch circuit to which an output of the power amplifier circuit is connected, the electronic device comprising: a wiring board;a first semiconductor chip mounted over a main surface of the wiring board, the first semiconductor chip including a MISFET (Metal Insulator Semiconductor Field Effect Transistor) formed therein for constituting the power amplifier circuit; anda second semiconductor chip mounted over the main surface of the wiring board for constituting the switch circuit.

2. The electronic device according to claim 1, wherein the first semiconductor chip further includes a control circuit for the switch circuit formed therein.

3. The electronic device according to claim 1, wherein the second semiconductor chip includes a HEMT (High Electron Mobility Transistor) or a diode formed therein for constituting the switch circuit.

4. The electronic device according to claim 1, wherein the electronic device is mounted over a mobile communication device.

5. The electronic device according to claim 4, wherein the switch circuit is a switch circuit serving as an antenna switch circuit for the mobile communication device.

6. The electronic device according to claim 1, further comprising a low pass filter circuit electrically connected between the power amplifier circuit and the switch circuit, wherein the low pass filter circuit is formed of an integrated passive element which is mounted over the main surface of the wiring board.

7. The electronic device according to claim 1, wherein the electronic device comprises the power amplifier circuits of first and second systems, the switch circuits of the first and second systems electrically connected to the outputs of the power amplifier circuits of the first and second systems, respectively, and the low pass filter circuits of the first and second systems electrically connected between the power amplifier circuits of the first and second systems and the switch circuits of the first and second systems, respectively,wherein the MISFETs constituting the power amplifier circuits of the first and second systems are formed in the first semiconductor chip,wherein the switch circuits of the first and second systems are formed in the second semiconductor chip, andwherein the low pass filter circuits of the first and second systems are formed of first and second integrated passive elements mounted over the main surface of the wiring board, respectively.

8. The electronic device according to claim 7, wherein a transmission frequency band of the power amplifier circuit of the first system is the 0.9 GHz band, andwherein a transmission frequency band of the power amplifier circuit of the second system is the 1.8 GHz band.

9. The electronic device according to claim 7, wherein the second semiconductor chip is disposed between the first integrated passive element and the second integrated passive element over the main surface of the wiring board.

10. The electronic device according to claim 9, wherein the second semiconductor chip is disposed next to the first semiconductor chip over the main surface of the wiring board.

11. The electronic device according to claim 10, wherein the first semiconductor chip further comprises a control circuit for the switch circuit formed therein, wherein the first semiconductor chip and the second semiconductor chip are electrically connected to each other via a conductive pattern of the wiring board or via the conductive pattern and a bonding wire over the main surface of the wiring board, andwherein a control signal of the switch circuit is supplied from the first semiconductor chip to the second semiconductor chip.

12. The electronic device according to claim 7, wherein no passive component is disposed between the first integrated passive element and the second semiconductor chip, and between the second integrated passive element and the second semiconductor chip over the main surface of the wiring board.

13. The electronic device according to claim 7, wherein electrical connections are established between the first integrated passive element and the second semiconductor chip, and between the second integrated passive element and the second semiconductor chip over the main surface of the wiring board via the conductive pattern of the wiring board or via the conductive pattern and the bonding wire without via the passive component.

14. The electronic device according to claim 1, further comprising an inductor element formed by the conductive pattern of the wiring board, wherein the inductor element is used for an output matching circuit of the power amplifier circuit.

15. The electronic device according to claim 7, wherein a plurality of first electrodes of the first semiconductor chip and a plurality of second electrodes of the wiring board are electrically connected to each other via a plurality of bonding wires over the main surface of the wiring board, andwherein each of the plurality of bonding wires is prevented from passing through and on another second electrode having a potential different from that of the second electrode connected.

16. The electronic device according to claim 15, wherein the plurality of second electrodes are arranged in line around the first semiconductor chip over the main surface of the wiring board.

17. The electronic device according to claim 16, wherein the first semiconductor chip further includes a control circuit for the switch circuit formed therein.

18. An electronic device including a power amplifier circuit and a low pass filter circuit electrically connected to the power amplifier circuit, the electronic device comprising: a wiring board;a first semiconductor chip mounted over a main surface of the wiring board for constituting the power amplifier circuit; andan integrated passive element mounted over the main surface of the wiring board for constituting the lowpass filter circuit,wherein a pattern for identifying a position of the integrated passive element is formed over the main surface of the wiring board.

19. The electronic device according to claim 18, wherein the pattern for identifying the position of the integrated passive element is formed of the same conductive layer as that of a plurality of fourth electrodes disposed over the main surface of the wiring board and electrically connected to a plurality of third electrodes of the integrated passive element.

20. The electronic device according to claim 18, wherein the pattern for identifying the position of the integrated passive element is provided at least in a part around the integrated passive element over the main surface of the wiring board, andwherein the integrated passive element does not exist directly above at least one part of the pattern for identifying the position of the integrated passive element.