RF circuit module and its manufacturing method

Abstract

To configure an RF circuit module that can improve heat dissipation and can be miniaturized, and suppresses the deterioration of the electrical characteristics of a circuit due to a wire to form an RF circuit module having excellent high frequency performance.SOLUTION: An RF circuit module 113A includes a module board 90, a first base material 10 in which a first circuit is configured, and a second base material 20 in which a second circuit is configured. The first circuit includes a control circuit that controls the operation of the second circuit, and the second circuit includes a high-frequency amplifier circuit that amplifies an RF signal. The second base material 20 is mounted on the first base material 10, and the first base material 10 is arranged on the module board 90 such that circuit forming surfaces face each other. The first base material 10 and the second base material 20 have an inter-circuit connection wiring 32 that electrically connects the first circuit and the second circuit without going through the module board 90.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an RF circuit module, and more particularly to an RF circuit module that is used in a circuit that handles high frequency power and has a heat generating portion, and a method for manufacturing the same. [Background technology]

[0002] Conventionally, RF front-end modules that integrate the transmission and reception functions of high-frequency signals have been built into electronic devices for mobile communications, satellite communications, etc. RF front-end modules are composed of a high-frequency amplifier, a control IC that controls the high-frequency amplifier, a switch IC, a duplexer, etc., mounted on a module substrate, and the entire module is molded in resin.

[0003] For example, the high frequency amplifier is a monolithic microwave integrated circuit (MMIC) formed on a GaAs substrate, and the control IC and switch IC are MMICs formed on a Si substrate, and are individually mounted on the surface of a module substrate.

[0004] On the other hand, in order to reduce the size of the module substrate, Patent Document 1 discloses a structure in which a control IC and the like are stacked on a high-frequency amplifier, and the high-frequency amplifier and the control IC and the like are wire-bonded to electrodes on the module substrate.

[0005] Fig. 25(A) is a plan view of a device having a similar configuration to the device shown in Patent Document 1, and Fig. 25(B) is its cross-sectional view. In this example, a heterojunction bipolar transistor die (HBT DIE) is mounted on a circuit board (LAMINATE SUBSTRATE), a silicon die (Si DIE) is mounted on this die, and wire bonding is performed between the heterojunction bipolar transistor die and the circuit board, between the silicon die and the circuit board, and between the silicon die and the heterojunction bipolar transistor die. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent Application Publication No. 2015 / 0303971 Summary of the Invention [Problem to be solved by the invention]

[0007] In a structure in which the high-frequency amplifier, control IC, switch IC, etc. are individually mounted on the surface of the module substrate, the mounting area of ​​these components on the module substrate is large, and the wiring connecting the components is long and the signal loss is large. In addition, since the high-frequency amplifier is constructed on a GaAs substrate, for example, the high-frequency amplifier itself has low heat dissipation.

[0008] According to the structure disclosed in Patent Document 1, the size of the module board can be reduced compared to the case where a high-frequency amplifier and a control IC, which occupy a relatively large area, are arranged side by side. However, space is required for wire bonding, and the reduction effect of the module board is small. In addition, the influence of parasitic inductance generated in the wires increases losses especially in the high-frequency range and impedance mismatch of the lines is likely to occur. In addition, the heat dissipation effect of the heat generated by the high-frequency amplifier is low.

[0009] On the other hand, with the recent demand for higher speed and output of high-frequency amplifiers, the characteristic limit due to self-heating has become an issue. For example, in a bipolar transistor, heat is generated due to the collector loss, and the temperature rise of the bipolar transistor itself reduces the base-emitter saturation voltage Vbe, which in turn increases the collector current and further reduces Vbe. This positive feedback leads to thermal runaway, which limits the power that can be handled within a controllable range.

[0010] Therefore, if the heat of the high-frequency amplifier cannot be dissipated with high efficiency when the RF circuit module is constructed, it will be impossible to reduce the size of the RF circuit module.

[0011] Therefore, an object of the present invention is to provide an RF circuit module that is miniaturized without being restricted by heat dissipation, or an RF circuit module that is small but has high heat dissipation, and a manufacturing method for the RF circuit module. Another object of the present invention is to provide an RF circuit module that has excellent high frequency performance by suppressing deterioration of the electrical characteristics of the circuit due to wires, and a manufacturing method for the RF circuit module. [Means for solving the problem]

[0012] (1) An RF circuit module according to one embodiment of the present disclosure comprises: A module substrate having electrodes for mounting components; A first substrate having a first circuit formed thereon; A second substrate having a second circuit formed thereon; Equipped with the first circuit includes a control circuit that controls an operation of the second circuit; the second circuit includes a high frequency amplifier circuit that amplifies an RF signal; the second substrate is mounted to the first substrate; the first substrate is flip-chip bonded to the module substrate; the first base material and the second base material each have a conductor layer that constitutes an inter-circuit connection wiring that electrically connects the first circuit and the second circuit without passing through the module substrate; the first base material has a first base material side conductor protrusion portion connected to the electrode of the module board, The second base material has a second base material side conductor protrusion portion connected to the electrode of the module board.

[0013] (2) An RF circuit module according to one embodiment of the present disclosure includes: A module substrate having electrodes for mounting components; A first substrate having a first circuit formed thereon; A second substrate having a second circuit formed thereon; Equipped with the first circuit includes a control circuit for controlling an operation of the second circuit; the second circuit includes a high frequency amplifier circuit for amplifying an RF signal; the second substrate is mounted to the first substrate; the first base material and the second base material each have a conductor layer that constitutes an inter-circuit connection wiring that electrically connects the first circuit and the second circuit without passing through the module substrate; In a plan view of the module substrate, an upper surface of a conductor layer that constitutes the inter-circuit connection wiring is located below an upper surface of the second circuit.

[0014] (3) A method for manufacturing an RF circuit module according to one embodiment of the present disclosure includes: A method for manufacturing an RF circuit module including: a module substrate having electrodes for mounting components; a first substrate having a first circuit including a control circuit; and a second substrate having a second circuit including a high-frequency amplifier circuit controlled by the control circuit, the method comprising the steps of: forming the first circuit and an inter-substrate connection conductor on the first substrate, which is a single semiconductor substrate; forming a semiconductor thin film having the second circuit and an inter-substrate connection conductor on a compound semiconductor substrate, which is the second substrate, via a release layer; removing the release layer by etching to release the semiconductor thin film from the compound semiconductor substrate to form the second substrate; a step of joining the second base material to a predetermined position of the first base material to connect the inter-base material connection conductor of the first base material to the inter-base material connection conductor of the second base material, thereby forming a laminate of the first base material and the second base material; forming a first substrate-side conductor projection connected to the first circuit and a second substrate-side conductor projection connected to the second circuit; The electrodes of the module substrate are provided with the first substrate-side conductor projections and the second substrate-side conductor projections. of mounting the stack to the module substrate by connecting; has.

[0015] (4) A method for manufacturing an RF circuit module according to one embodiment of the present disclosure includes: A method for manufacturing an RF circuit module including: a module substrate having electrodes for mounting components; a first substrate having a first circuit including a control circuit; and a second substrate having a second circuit including a high-frequency amplifier circuit controlled by the control circuit, the method comprising the steps of: forming the first circuit on the first substrate, which is a free-standing semiconductor substrate; forming a semiconductor thin film having the second circuit on a compound semiconductor substrate, which is the second substrate, via a release layer; removing the release layer by etching to release the semiconductor thin film from the compound semiconductor substrate to form the second substrate; a step of bonding the second base material to a predetermined position of the first base material to form a laminate of the first base material and the second base material; forming an inter-substrate connection conductor connecting the first circuit and the second circuit; mounting the laminate on the module substrate; has. Effect of the Invention

[0016] According to the present invention, it is possible to obtain an RF circuit module that is miniaturized without being restricted by heat dissipation, or an RF circuit module that is small but has high heat dissipation properties. In addition, it is possible to obtain an RF circuit module that has excellent high frequency performance by avoiding deterioration of the electrical characteristics of the circuit due to wires. [Brief description of the drawings]

[0017] [Figure 1] Fig. 1(A) is a plan view of an RF circuit module 111 according to a first embodiment. Fig. 1(B) is a cross-sectional view taken along the line XX in Fig. 1(A). [Diagram 2] 2A and 2B are diagrams showing the manufacturing process of the RF circuit module 111. [Diagram 3] FIG. 3 is a diagram showing two heat conduction paths, which are heat dissipation paths from the circuit elements formed on the second base material 20 in the RF circuit module 111. As shown in FIG. [Figure 4]FIG. 4 is a diagram showing a method for manufacturing the PA circuit element 3. In FIG. [Diagram 5] FIG. 5 is a diagram illustrating a method for producing the second base material 20 and a method for bonding the second base material 20 to the first base material 10, and is a perspective view of each step. [Figure 6] FIG. 6A is a plan view of a front-end module 120 according to the second embodiment, and FIG. 6B is a cross-sectional view of a portion XX in FIG. 6A. [Figure 7] FIG. 7 is a block diagram showing a circuit configuration of a front-end module 120 according to the second embodiment. [Figure 8] FIG. 8 is a partial cross-sectional view of an RF circuit module 113A according to the third preferred embodiment. [Figure 9] FIG. 9 is a partial enlarged view showing the configuration of an HBT formed on second base material 20. As shown in FIG. [Figure 10] FIG. 10 is a diagram showing two heat conduction paths, which are heat dissipation paths from the circuit element 21 in the RF circuit module 113A. [Figure 11] FIG. 11 is a partial cross-sectional view of another RF circuit module 113B according to the third preferred embodiment. [Figure 12] FIG. 12 is a cross-sectional view of the heat spreader HS at the via layer. [Figure 13] FIG. 13 is a diagram showing a heat dissipation path from the circuit element 21 in the RF circuit module 113B. [Figure 14] FIG. 14 is a partial cross-sectional view of still another RF circuit module 113C according to the third preferred embodiment. [Figure 15] FIG. 15 is a cross-sectional view of a laminate 104A included in an RF circuit module according to the fourth preferred embodiment. [Figure 16] FIG. 16 is a cross-sectional view of another circuit module 114B according to the fourth embodiment. [Figure 17] FIG. 17 is a diagram showing a method for manufacturing a laminate including a PA circuit element and the like according to the fourth embodiment. [Figure 18]FIG. 18 is a block diagram showing a circuit configuration of a front-end module 120 according to the fourth embodiment. [Figure 19] FIG. 19 is a cross-sectional view of an RF circuit module 115 according to the fifth embodiment. [Figure 20] FIG. 20 is a schematic front view of an RF circuit module 116A according to the sixth embodiment. [Figure 21] FIG. 21 is a front view of another RF circuit module 116B according to the sixth embodiment. [Figure 22] FIG. 22 is a front view of an RF circuit module 117A according to the seventh preferred embodiment. [Diagram 23] FIG. 23 is a front view of another RF circuit module 117B according to the seventh embodiment. [Figure 24] 24(A) and 24(B) are diagrams showing the configuration of a front-end module as a comparative example of the front-end module according to the second embodiment. [Diagram 25] FIG. 25(A) is a plan view of a device having a similar configuration to the device shown in Patent Document 1, and FIG. 25(B) is its cross-sectional view. [Figure 26] FIG. 26 is a diagram showing the configuration of an RF circuit module as a comparative example of the RF circuit module according to the fourth embodiment. [Figure 27] FIG. 27 is a diagram showing the configuration of an RF circuit module serving as another comparative example of the RF circuit module according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, several specific examples will be given with reference to the drawings to show several embodiments for carrying out the present invention. In each drawing, the same reference numerals are given to the same parts. In consideration of the ease of explanation or understanding of the main points, the embodiments are shown divided into several embodiments for convenience of explanation, but partial replacement or combination of the configurations shown in different embodiments is possible. In the second and subsequent embodiments, the description of matters common to the first embodiment will be omitted, and only the differences will be described. In particular, similar actions and effects due to similar configurations will not be mentioned in each embodiment.

[0019] First Embodiment In the first embodiment, an RF circuit module including basic components will be illustrated.

[0020] Fig. 1(A) is a plan view of an RF circuit module 111 according to a first embodiment. Fig. 1(B) is a cross-sectional view of part XX in Fig. 1(A). This RF circuit module 111 includes a module substrate 90 having module substrate side electrodes 91, 92 for mounting components, a first base material 10 having a first circuit formed thereon, a second base material 20 having a second circuit formed thereon, and a molded resin 100. The module substrate 90 is, for example, a PCB (Printed Circuit Board) such as a glass-epoxy substrate. The molded resin 100 is, for example, an epoxy resin.

[0021] The first circuit includes a control circuit that controls the operation of the second circuit, and the second circuit includes a high-frequency amplifier circuit that amplifies an RF signal. The second substrate 20 is mounted on the first substrate 10, and the first substrate 10 is flip-chip bonded (mounted face down) to the module substrate 90.

[0022] The first substrate 10 and the second substrate 20 have inter-circuit connection wiring that electrically connects the circuits formed on the first substrate 10 and the circuits formed on the second substrate 20 without going through the module substrate 90.

[0023] The first substrate 10 has a first substrate-side electrode 12 and a first conductive pillar bump PB1, and the second substrate 20 has a second substrate-side electrode 22 and a second conductive pillar bump PB2. The first conductive pillar bump PB1 corresponds to the "first substrate-side conductive protrusion" according to the present invention, and the second conductive pillar bump PB2 corresponds to the "second substrate-side conductive protrusion" according to the present invention.

[0024] The first conductor pillar bump PB1 is composed of a conductor pillar 13 formed on the first substrate side electrode 12 of the first substrate 10, and a solder layer 14 applied to the tip of the conductor pillar 13. The second conductor pillar bump PB2 is composed of a conductor pillar 23 formed on the second substrate side electrode 22 of the second substrate 20, and a solder layer 24 applied to the tip of the conductor pillar 23. The conductor pillars 13, 23 are, for example, Cu plating films, and the solder layers 14, 24 are, for example, SnAg alloy films.

[0025] The first circuit formed on the first base material 10 and the second circuit formed on the second base material 20 face the electrode formation surface of the module substrate 90.

[0026] Module substrate side electrodes 91, 92 are formed on the module substrate 90. The first conductive pillar bump PB1 of the first base material 10 is connected to the module substrate side electrode 91 of the module substrate 90. In addition, the second conductive pillar bump PB2 of the second base material 20 is connected to the module substrate side electrode 92 of the module substrate 90.

[0027] In this way, the first circuit formed on the first base material 10 and the second circuit formed on the second base material 20 face the electrode formation surface of the module substrate 90 and are connected to the module substrate side electrodes 91, 92 of the module substrate 90 via the first conductive pillar bump PB1 and the second conductive pillar bump PB2, thereby minimizing the path between the first circuit and the circuit on the module substrate 90 side and the path between the second circuit and the circuit on the module substrate 90 side. This suppresses deterioration of electrical characteristics in the signal paths.

[0028] After the power amplifier module (PA circuit element 3, which will be described later) including the first base material 10 and the second base material 20 is mounted on the module substrate 90, the surface of the module substrate 90 is molded with molding resin 100.

[0029] 2(A) and 2(B) are diagrams showing the manufacturing process of the RF circuit module 111. Fig. 2(A) is a cross-sectional view showing a state immediately before mounting a PA circuit element 3 including a first base material 10 and a second base material 20 on a module substrate 90. Fig. 2(B) is a cross-sectional view showing a state after the PA circuit element 3 has been mounted on the module substrate 90.

[0030] A method for forming the PA circuit element 3 will be described later. A first conductive pillar bump PB1 and a second conductive pillar bump PB2 are formed on the underside of the PA circuit element 3. The first conductive pillar bump PB1 and the second conductive pillar bump PB2 of this PA circuit element 3 are aligned with the module substrate 90 and heated and pressurized, whereby the solder layers 14, 24 of the first conductive pillar bump PB1 and the second conductive pillar bump PB2 of the PA circuit element 3 are connected to the module substrate side electrodes 91, 92, as shown in Fig. 2(B).

[0031] 3 is a diagram showing two heat conduction paths, which are heat dissipation paths from the circuit elements formed on the second substrate 20 in the RF circuit module 111. In FIG. 3, dashed arrows indicate the two heat conduction paths. The first heat conduction path is formed by the second substrate side electrode 22 and the second conductive pillar bump PB2, and heat generated by the circuit elements is dissipated and exhausted to the module substrate side electrode 92 and the module substrate 90 via this first heat conduction path. The second heat conduction path is a heat conduction path from the second substrate 20 to the first substrate 10, and heat generated by the circuit elements is dissipated and exhausted via the second heat conduction path.

[0032] The second conductive pillar bump PB2 is provided in close proximity to the second substrate side electrode 22 which is part of the second circuit formed on the second substrate 20. Therefore, the heat dissipation and waste heat efficiency is high.

[0033] The height of the first conductive pillar bump PB1 is smaller than the thickness of the first base material 10. Therefore, the wiring length can be made shorter and the loop inductance can be reduced compared to the case where the first base material 10 on which the second base material 20 is mounted is connected to the module substrate 90 by a mounting technique such as wire bonding.

[0034] Next, a method for manufacturing the RF circuit module 111 will be illustrated. Fig. 4 is a diagram showing the method for manufacturing the PA circuit element 3. Steps S1 to S7 in Fig. 4 are cross-sectional views of the PA circuit element 3 during the manufacturing process, and step S8 is a cross-sectional view of the completed PA circuit element 3. Although the actual manufacturing is performed in wafer units, Fig. 4 illustrates a single semiconductor device.

[0035] First, as shown in step S1 in Fig. 4, a first base material 10 made of a Si base material is placed. If necessary, a bonding layer may be formed on the surface of the first base material 10 made of the Si base material using a general semiconductor process. This bonding layer is a metal film such as an Au film, an organic material film such as a polyimide (PI) film, polybenzoxazole (PBO) or benzocyclobutene (BCB), or an insulator such as AlN, SiC or diamond.

[0036] Next, as shown in step S2, the second base material 20 is bonded onto the first base material 10. Circuit elements and electrodes have already been formed on the second base material 20 in a separate process.

[0037] Next, as shown in step S3, the second substrate side electrode 22 is formed on the second substrate 20, and the first substrate side electrode 12 is formed on the first substrate 10 by a general semiconductor process.

[0038] Next, as shown in step S4, a resist film 85 having openings in areas where the conductor pillars 13 and the solder layers 14 (FIGS. 2A and 2B) are to be formed is formed. In the openings of the resist film 85, the electrodes 12 and 22 are exposed.

[0039] Thereafter, as shown in steps S5 and S6, the conductor pillars 13, 23 and the solder layers 14, 24 are deposited by plating on the electrodes 12, 22 exposed in the openings of the resist film 85. The conductor pillars 13, 23 are made of Cu and have a thickness of, for example, 40 μm. In this manner, a CPB (Copper Pillar Bump) is formed. The solder layers 14, 24 are made of a SnAg alloy and have a thickness of, for example, 30 μm.

[0040] Thereafter, as shown in step S7, resist film 85 is removed, and finally, a reflow process is performed to melt solder layers 14 and 24, which are then solidified to obtain PA circuit element 3 as shown in step S8.

[0041] 5 is a perspective view of each step of a method for manufacturing the second base material 20 and a method for bonding the second base material 20 to the first base material 10. Although the actual manufacturing is performed in wafer units, FIG. 5 illustrates a single semiconductor device.

[0042] 5, first, a release layer 29 is formed on a mother substrate 200, which is a compound semiconductor substrate, and then a semiconductor thin film is formed on the top of the release layer 29 by epitaxial growth. Then, a plurality of circuit elements and electrodes connected to the circuit elements are formed on the semiconductor thin film. This portion is the second substrate 20.

[0043] Next, as shown in step S12, a process of selectively etching only the release layer 29 is performed, whereby the second base material 20 (the semiconductor thin film piece) is peeled off from the mother substrate 200.

[0044] Thereafter, as shown in step S13, the second substrate 20 is bonded to the first substrate 10. That is, the semiconductor thin film pieces are transferred from the mother substrate 200 to the first substrate 10. This bonding is achieved by van der Waals bonds or hydrogen bonds. Alternatively, the bonding may be achieved by electrostatic forces, covalent bonds, eutectic alloy bonds, or the like. Alternatively, in a separate process, an Au film may be formed on the first substrate 10 as a bonding layer, and the second substrate 20 may be pressed against and adhered to the surface of the bonding layer, so that the Au of the bonding layer diffuses into the GaAs layer of the second substrate to form a eutectic bond, thereby achieving bonding.

[0045] The formation of circuit elements and electrodes on the second substrate 20 may be performed not only by the step shown in step S11, but also by a process (photolithography and etching process) on the second substrate 20 after the second substrate 20 is bonded to the first substrate 10, as shown in step S14.

[0046] The method of peeling and transferring the semiconductor thin film piece can be the method disclosed in Japanese Patent No. 5132725. That is, as shown in step S12 in FIG. 5, when peeling the second substrate 20 (semiconductor thin film piece) from the mother substrate 200, the second substrate 20 is peeled from the mother substrate 200 while being supported by a support. Also, as shown in step S13 in FIG. 5, when bonding the second substrate 20 to the first substrate 10, it is performed while being supported by the support. In steps S12 and S13 in FIG. 5, the support is omitted for the convenience of clearly showing the second substrate 20.

[0047] The RF circuit module 111 of this embodiment configured as above provides the following effects.

[0048] (a) The first base material 10 is flip-chip bonded (mounted face down) to the module substrate 90, eliminating the need for space to place wire-bonding pads and wires, allowing for an overall compact size.

[0049] (b) Since the first substrate 10 and the second substrate 20 are electrically connected by inter-substrate connecting conductors, without going through the module substrate 90, and since the first substrate 10 has a first conductive pillar bump PB1 connected to an electrode of the module substrate 90, and the second substrate 20 has a second conductive pillar bump PB2 connected to an electrode of the module substrate 90, there is no need to form wiring on the module substrate 90 to connect the circuit formed on the first substrate 10 and the circuit formed on the second substrate 20, and the overall size can be reduced.

[0050] (c) Since the heat generated by the high-frequency amplifier circuit formed on the second substrate 20 can be dissipated and removed with high efficiency, it is possible to obtain a miniaturized RF circuit module without being restricted by heat dissipation properties, or an RF circuit module which is compact yet has high heat dissipation properties.

[0051] Second Embodiment In the second embodiment, an RF circuit module configured as a front-end module will be illustrated.

[0052] Fig. 6(A) is a plan view of a front-end module 120 according to a second embodiment, and Fig. 6(B) is a cross-sectional view of a portion XX in Fig. 6(A). However, Fig. 6(A) is a plan view without a top shield layer and a molded resin, which will be described later.

[0053] This front-end module 120 is a circuit connected between an antenna and a transmitting circuit and a receiving circuit. This front-end module 120 is configured by mounting a plurality of chip components on a module substrate 90. Ground conductors are formed on the inner layer and the bottom layer of the module substrate 90. An antenna switch 70, a low-noise amplifier 67, a PA circuit element 3, a duplexer, a chip inductor, a chip capacitor, and the like are mounted on the module substrate 90. The upper part of the module substrate 90 is molded with a molded resin 100, and a metal layer for a top surface shield is formed on the surface of the molded resin 100.

[0054] The PA circuit element 3 is a PA module composed of a first substrate 10 and a second substrate 20. A switch for selecting one of two transmission signals (described later) and a control circuit for a high-frequency amplifier are formed on the first substrate 10. A high-frequency amplifier circuit is formed on the second substrate 20.

[0055] 7 is a block diagram showing a circuit configuration of a front-end module 120 according to this embodiment. The front-end module 120 includes a band-pass filter 71 connected to an antenna ANT, an antenna switch 70, impedance matching circuits 69A and 69B, duplexers 68A and 68B, a switch 65, an impedance matching circuit 66, a low-noise amplifier 67, a switch 62, a high-frequency amplifier 60, a high-frequency amplifier control circuit 61, an impedance matching circuit 63, and a switch 64.

[0056] The switch 62 and the high frequency amplifier control circuit 61 are formed on the first substrate 10, and the high frequency amplifier 60 is formed on the second substrate.

[0057] 7, an antenna switch 70 is a switch that selects the connection between the antenna and two transmission / reception circuit systems. A low noise amplifier 67 is a first-stage amplifier for the received signal.

[0058] Here, a configuration example of a front-end module as a comparative example of the front-end module according to the second embodiment is shown in Figures 24(A) and 24(B). Figure 24(B) is a cross-sectional view of part XX in Figure 24(A). Unlike the examples shown in Figures 6(A) and 6(B), this includes a high-frequency amplifier 60, a high-frequency amplifier control circuit 61, and a switch 62, which are individual components.

[0059] According to the second embodiment, as is clear from a comparison with the front-end module shown in Figures 24(A) and 24(B) as a comparative example, the mounting area of ​​electronic components on the module substrate 90 is reduced. Furthermore, the wiring length between the high-frequency amplifier 60 and the switch 62 and the wiring length between the high-frequency amplifier 60 and the high-frequency amplifier control circuit 61 are shortened, reducing signal loss and impedance mismatch.

[0060] Furthermore, since the switch 62 and the high-frequency amplifier control circuit 61 are configured on the first substrate 10, the size is appropriately larger than the size of the switch 62 alone or the high-frequency amplifier control circuit 61 alone, facilitating the formation of the PA circuit element 3, which is a laminate of the first substrate 10 and the second substrate 20 on which the high-frequency amplifier 60 is formed. Furthermore, by configuring the PA circuit element 3 as a laminate of the first substrate 10 and the second substrate 20, the efficiency of reducing the area of ​​the front-end module 120 is improved.

[0061] In addition, in the conventional configuration in which, for example, a GaAs substrate is connected by wire bonding or bumps, a thick GaAs substrate is required for handling. However, in this embodiment, a thin second substrate 20, for example a GaAs substrate, is attached to a first substrate 10, for example a Si substrate, so that a low height can be achieved even though the two chips are stacked.

[0062] Third embodiment In the third embodiment, several configuration examples of an RF circuit module including a PA circuit element will be described.

[0063] Fig. 8 is a partial cross-sectional view of an RF circuit module 113A according to the third preferred embodiment of the present invention, which shows a cross section of the PA circuit element 3 and a part of a module substrate 90 on which the PA circuit element 3 is mounted.

[0064] Module substrate side electrodes 91, 92 for mounting components are formed on a module substrate 90 made of a PCB (Printed Circuit Board). The PA circuit element 3 includes a first conductive pillar bump PB1 and a second conductive pillar bump PB2. The first conductive pillar bump PB1 and the second conductive pillar bump PB2 of the PA circuit element 3 are connected to the module substrate side electrodes 91, 92 of the module substrate 90, thereby mounting the PA circuit element 3 face-down. The structures of the first conductive pillar bump PB1 and the second conductive pillar bump PB2 are as shown in the first embodiment.

[0065] The PA circuit element 3 includes a first base material 10 and a second base material 20. The first base material 10 has a SiO2 layer as an insulating layer, a Si layer as a device layer, a SiO2 layer as a wiring formation layer, and a SiN layer as a passivation layer formed in this order on a Si substrate Si-sub.

[0066] A plurality of circuit elements 21 and electrodes for applying an operating voltage or passing an operating current to the plurality of circuit elements 21 are formed on the second substrate 20. The second substrate 20 is formed in a separate process as shown in Fig. 5 in the first embodiment, and the circuit elements are formed on the epitaxial layer. The epitaxial layer is, for example, about 3 µm thick, and the electrodes (wiring layer) are about 10 µm thick.

[0067] On the surface of the SiN layer, there are formed rewiring layers: a first substrate-side electrode 12, a second substrate-side electrode 22, and an inter-circuit connection wiring 32. During manufacture, the conductor layer constituting the inter-circuit connection wiring 32 is made of the same layer as the second substrate-side electrode 22 (the "conductor layer constituting the second circuit" according to the present invention).

[0068] 8, one of the first conductor pillar bumps PB1 is in direct contact with the conductor layer that constitutes the inter-circuit connection wiring 32. Therefore, a part of the first circuit and a part of the second circuit are connected via a short path, and also connected to the circuit on the module substrate side via a short path.

[0069] The surfaces of the first substrate side electrode 12 , the second substrate side electrode 22 and the inter-circuit connection wires 32 are insulated and coated with a resin layer 15 .

[0070] In this embodiment, the first substrate 10 is a substrate of a single semiconductor, and is mainly composed of, for example, Si or Ge. The first substrate 10 may be composed of a plurality of materials including any of GaAs, AlAs, InAs, InP, GaP, InSb, GaN, InN, AlN, SiC, Ga2O3, DLC (Diamond-Like Carbon), Graphite, Diamond, Glass, Sapphire, and Al2O3.

[0071] In this embodiment, the second substrate 20 is a compound semiconductor substrate, and is made of, for example, any one of GaAs, AlAs, InAs, InP, GaP, InSb, GaN, InN, AlN, SiGe, SiC, Ga2O3, and GaBi. The second substrate 20 may be a multi-element mixed crystal material made of a plurality of these materials.

[0072] However, the material selected for the first substrate 10 is different from the material selected for the second substrate 20, and the manufacturing processes for the first substrate 10 and the second substrate 20 are different. Basically, the second substrate 20 is made of a material that provides predetermined electrical characteristics such as an amplification factor and a cutoff frequency, and the first substrate 10 is preferably selected to have a higher thermal conductivity than the second substrate 20.

[0073] In this embodiment, the first substrate 10 is a Si substrate, and the second substrate 20 is a GaAs substrate. The thermal conductivity of the Si substrate is 156, and the thermal conductivity of the GaAs substrate is 46. The circuit element 21 is, for example, a heterojunction bipolar transistor (HBT) in which a plurality of unit transistors are connected in parallel, and is formed by a process on the GaAs substrate, which is the second substrate 20. The conductor pillar bump PB2 is electrically connected to the emitters of the plurality of unit transistors. The plurality of unit transistors are arranged in a first direction (the left-right direction in FIGS. 1(A) and 1(B)), and the conductor pillar bump PB2 is formed in a shape that extends in the first direction as well.

[0074] 9 is a partial enlarged view showing the configuration of an HBT formed on a second substrate 20. The second substrate 20 includes a GaAs substrate 20N and an epitaxial layer 20D formed on the surface thereof. A circuit element 21 (HBT) is formed on the epitaxial layer 20D. The second substrate 20 serves as a common collector. The emitters of the multiple HBTs are commonly connected via a base electrode 22U and a second substrate-side electrode 22.

[0075] 8, a CMOS circuit including a P-channel MOS PM and an N-channel MOS NM is formed in the Si layer as the device layer. Between the Si layer as the device layer and the SiN layer as the passivation layer, wiring is formed to extend the circuit formed in the Si layer as the device layer to the first substrate side electrode 12 and the inter-circuit connection wiring 32. This wiring is composed of multiple wiring layers made of Cu or Al and vias V made of Cu or Al that connect between the wiring layers.

[0076] Fig. 10 is a diagram showing two heat conduction paths, which are heat dissipation paths from the circuit element 21 in the RF circuit module 113A. In Fig. 10, dashed arrows indicate the two heat conduction paths. The first heat conduction path is formed by the second substrate side electrode 22 and the second conductive pillar bump PB2, and heat generated by the circuit element 21 is dissipated and exhausted to the module substrate side electrode 92 and the module substrate 90 via this first heat conduction path. The second heat conduction path is a heat conduction path from the second substrate 20 to the first substrate 10, and heat generated by the circuit element 21 is dissipated and exhausted via the second heat conduction path.

[0077] The thermal conductivity of the SiO2 layer as the wiring formation layer is 1.0 [W / cm K], the thermal conductivity of the Si base material is 156 [W / cm K], and the thermal conductivity of the GaAs substrate is 46 [W / cm K]. That is, the thermal conductivity of the first base material 10 is higher than that of the second base material 20. Therefore, the first base material 10 acts as a highly efficient heat radiator. Since the first base material 10 acts as a heat conduction path in this way, the conductor pillar 13, the solder layer 14, and the module substrate side electrode 92 also act as heat conduction paths.

[0078] In the examples shown in FIGS. 8 and 10, the heat dissipation and exhaust effect to the module substrate 90 side is high, so that the thermal influence on the CMOS circuit and the like is suppressed.

[0079] In the RF circuit module 113A configured in this manner, similarly to the example shown in the first embodiment, an RF circuit module that is miniaturized overall and has high heat dissipation properties is obtained.

[0080] Fig. 11 is a partial cross-sectional view of another RF circuit module 113B according to the third embodiment. It differs from the RF circuit module 113A shown in Fig. 8 in that it includes a heat spreader HS. In this RF circuit module 113B, not only is wiring formed in the SiO2 layer as the wiring formation layer, leading the circuit formed in the Si layer as the device layer to the first substrate side electrode 12, but also a heat spreader HS is formed in the vicinity of the circuit element 21, which is an HBT. This heat spreader HS is composed of multiple wiring layers made of Cu or Al and vias V made of Cu or Al that connect the wiring layers.

[0081] Figure 12 is a cross-sectional view of the via layer of the heat spreader HS. As shown, the conductor of the wiring layer constituting the heat spreader HS spreads out in a planar shape, and a large number of vias are arranged in the planar direction. In this way, the heat spreader HS has a lattice-like shape in both the horizontal and vertical cross-sectional directions, with the wiring layer (conductor layer) and the periphery of the vias (insulator layer).

[0082] FIG. 13 is a diagram showing heat dissipation paths from the circuit element 21 in the RF circuit module 113B. In FIG. 13, as shown by dashed arrows, heat generated by the circuit element 21 (HBT) is dissipated and exhausted through three heat conduction paths. The first heat conduction path is a path for dissipating and exhausting the heat of the circuit element 21 to the module board side electrode 92 and the module board 90 via the second substrate side electrode 22 and the second conductive pillar bump PB2. The second heat conduction path is a path for dissipating and exhausting the heat generated by the circuit element 21 to the first substrate 10. The third heat conduction path is a path for dissipating and exhausting the heat of the circuit element 21 to the module board side electrode 91 and the module board 90 via the heat spreader HS, the first substrate side electrode 12, and the first conductive pillar bump PB1. Since the heat spreader HS is formed on this first base material 10, the heat in the direction of the first base material 10 is dissipated and exhausted with high efficiency via the heat spreader HS. In addition, since the third heat conduction path is also formed, the heat of the circuit element 21 is dissipated and exhausted with high efficiency.

[0083] Fig. 14 is a partial cross-sectional view of yet another RF circuit module 113C according to the third embodiment. This RF circuit module 113C differs from the RF circuit module 113B shown in Fig. 11 in that the area in which the heat spreader HS is formed is wider. In this RF circuit module 113C, the size of the heat spreader HS is large, so that the heat of the circuit element 21 is effectively dissipated via the heat spreader HS. Also, compared to the example shown in Fig. 13, a plurality of heat conduction paths are formed to dissipate and exhaust the heat of the circuit element 21 to the module substrate side electrode 91 and the module substrate 90 via the heat spreader HS, the first substrate side electrode 12, and the first conductive pillar bump PB1, so that the heat dissipation effect via these heat conduction paths is also high.

[0084] In the RF circuit modules 113B and 113C configured in this manner, a heat dissipation / waste heat path to the heat spreader HS is added, and further, a heat conduction path via the first substrate side electrode 12 and the first conductive pillar bump PB1 is added, thereby obtaining an RF circuit module with higher heat dissipation performance. Also, since the vias V of the heat spreader HS reach the Si substrate, the heat dissipation / waste heat efficiency of the Si substrate is high.

[0085] In the example shown in FIG. 12, the heat spreader HS has a wiring layer conductor that spreads in a planar shape, but the wiring layer conductor may have an independent pattern for each location where the via V is conductive. This suppresses eddy currents flowing in the wiring layer conductor. The wiring layer conductor may also have a lattice shape in a plan view of the wiring layer. This also suppresses eddy currents flowing in the wiring layer conductor.

[0086] Fourth embodiment In the fourth embodiment, an RF circuit module will be illustrated which is mounted on a module substrate in a state in which the circuit formation surface of a first base material is not opposed to the module substrate.

[0087] 15 is a cross-sectional view of a laminate 104A included in an RF circuit module according to the fourth embodiment. The PA circuit element 3 includes a first substrate 10 and a second substrate 20. The laminate 104A is a laminate made of the first substrate 10 and the second substrate 20.

[0088] The first base material 10 has a SiO2 layer as an insulating layer, a Si layer as a device layer, a SiO2 layer as a wiring formation layer, and a SiN layer as a passivation layer formed in this order on a Si substrate Si-sub. The first base material side electrode 12, the second base material side electrode 22, and the inter-circuit connection wiring 32 are formed on the surface of the SiN layer as rewiring layers.

[0089] During manufacturing, the inter-circuit connection wiring 32, the second substrate side electrode 22 (the "conductor layer constituting the second circuit" according to the present invention), and the conductor layer constituting the first substrate side electrode 12 may be configured in the same layer, which can simplify the manufacturing process.

[0090] A plurality of circuit elements 21 and electrodes for applying an operating voltage or passing an operating current to the plurality of circuit elements 21 are formed on the second substrate 20. The second substrate 20 is formed in a separate process as shown in Fig. 5 in the first embodiment, and the circuit elements are formed on the epitaxial layer thereof.

[0091] Furthermore, a first substrate side electrode 12 and an inter-circuit connection wiring 32 are formed on the surface of the first substrate 10 at a position that does not overlap with the second substrate 20. The surfaces of the first substrate side electrode 12, the second substrate side electrode 22, and the inter-circuit connection wiring 32 are exposed for external connection.

[0092] The configurations of the first substrate 10, the first circuit formed on the first substrate 10, the second substrate 20, and the second circuit formed on the second substrate 20 are the same as those in the example shown in FIG.

[0093] In the laminate 104A, the bottom surface of the first substrate 10 is mounted on a module substrate, and the first substrate side electrode 12, the second substrate side electrode 22 or the inter-circuit connection wiring 32 are connected to the electrodes on the module substrate via wires.

[0094] As indicated by the thin auxiliary lines in FIG. 15, in a plan view of the module substrate, the upper surface of the conductor layer that constitutes the inter-circuit connection wiring 32 is lower than the upper surface of the second substrate side electrode 22 that is the uppermost part of the second circuit.

[0095] 16 is a cross-sectional view of another circuit module 114B according to the fourth embodiment. The circuit module 114B includes a module substrate 90 and a laminate 104B.

[0096] The basic configuration of the laminate 104B is the same as that of the laminate 104A shown in Figure 15, but the surfaces of the first substrate 10 and the second substrate 20 are coated with a resin layer 15, and the surfaces of the external connection electrode (bonding pad) 31, the second substrate side electrode 22, and the inter-circuit connection wiring 32, which are conductive to the first substrate side electrode 12, are exposed from this resin layer 15.

[0097] The laminate 104B is mounted on a module substrate 90, and an external connection electrode 31 on the upper surface of the laminate 104B and an electrode 93 on the module substrate are connected via a wire 41.

[0098] In the example shown in FIG. 16, in a plan view of the module substrate 90, the upper surface of the conductor layer that constitutes the inter-circuit connection wiring 32 is flush with the upper surface of the second substrate side electrode 22 that is at the top of the second circuit.

[0099] In this embodiment as well, the conductor layers constituting the external connection electrode (bonding pad) 31 conductive to the first substrate side electrode 12, the second substrate side electrode 22, and the inter-circuit connection wiring 32 may be formed in the same layer, and forming them in the same layer can simplify the manufacturing process.

[0100] 17A to 17C are diagrams showing a method for manufacturing a laminate such as a power amplifier module according to the fourth embodiment, in particular, a method for forming inter-circuit connection wiring.

[0101] Steps S1 to S3 in Fig. 17 are cross-sectional views of a power amplifier module during the manufacturing process. Although the actual manufacturing process is performed in wafer units, Fig. 17 illustrates a single semiconductor device.

[0102] First, as shown in step S1 in Fig. 17, a first base material 10 made of a Si base material is placed. If necessary, a bonding layer may be formed on the surface of the first base material 10 made of the Si base material using a general semiconductor process. This bonding layer is a metal film such as an Au film, an organic material film such as a polyimide (PI) film, polybenzoxazole (PBO) or benzocyclobutene (BCB), or an insulator such as AlN, SiC, or diamond.

[0103] Next, as shown in step S2, the second base material 20 is bonded onto the first base material 10. Circuit elements and electrodes have already been formed on the second base material 20 in a separate process.

[0104] Next, as shown in step S3, a second-substrate-side electrode 22 is formed on the second substrate 20, a first-substrate-side electrode 12 is formed on the first substrate 10, and an inter-circuit connection wiring 32 is formed from the second substrate 20 to the first substrate 10 by a general semiconductor process. This inter-circuit connection wiring 32 connects a first circuit formed on the first substrate 10 and a second circuit formed on the second substrate 20.

[0105] The first substrate side electrode 12, the second substrate side electrode 22, and the inter-circuit connection wiring 32 can be formed simultaneously in one step.

[0106] 18 is a block diagram showing a circuit configuration of a front-end module 120 according to the fourth embodiment. The front-end module 120 includes a band-pass filter 71 connected to an antenna ANT, an antenna switch 70, impedance matching circuits 69A and 69B, duplexers 68A and 68B, switches 64 and 65, an impedance matching circuit 66, a low-noise amplifier 67, a switch 62, a high-frequency amplifier 60, a high-frequency amplifier control circuit 61, impedance matching circuits 63i and 63o, and a switch 64.

[0107] The switch 62 and the high-frequency amplifier control circuit 61 are formed in the first circuit 10C of the first substrate 10, and the high-frequency amplifier 60 is formed in the second circuit 20C of the second substrate 20. The impedance matching circuit 63o is formed in the first circuit 10C, the second circuit 20C, or both. The impedance matching circuit 63i is also formed in the first circuit 10C, the second circuit 20C, or both. Each of the impedance matching circuits 63i and 63o is composed of, for example, inductance and capacitance generated in a conductor portion connecting the first circuit 10C and the second circuit 20C.

[0108] The basic configuration of the front-end module 120 shown in Fig. 18 is the same as that of the front-end module 120 shown in Fig. 7. In Fig. 18, if the input part of the transmission signal to the switch 62 is represented by (1), the output part of the transmission signal to the first circuit 10C is represented by (2), and the input part of the transmission signal to the second circuit 20C is represented by (3), the paths of (2) and (3) are very close to each other.

[0109] Here, cross-sectional views of an RF circuit module as a comparative example are shown in Figures 26 and 27. In both of the examples shown in Figures 26 and 27, a first substrate 10 having a first circuit formed thereon is mounted on a module board 90, and a second substrate 20 having a second circuit formed thereon is mounted on this first substrate 10.

[0110] In the example shown in FIG. 26, module substrate side electrode 93A and a portion of the first circuit are connected via wire 41A, module substrate side electrode 93B and a portion of the first circuit are connected via wire 41B, and module substrate side electrode 93B and a portion of the second circuit are connected via wire 43.

[0111] In the example shown in FIG. 27, the module substrate side electrode 93 and a part of the first circuit are connected via a wire 41, and a part of the first circuit and a part of the second circuit are connected via a wire 42.

[0112] In the structure shown in Fig. 26, a part of the first circuit and a part of the second circuit are connected via wires 41B and 43, but this connection path is the path between (2) and (3) shown in Fig. 18, so the parasitic inductance and parasitic capacitance of the wires 41B and 43 are large, resulting in a large signal loss and making it difficult to obtain the desired characteristics of the impedance matching circuit 63i.

[0113] In the structure shown in Fig. 27, a part of the first circuit and a part of the second circuit are connected via a wire 42, but this connection path is the path between (2) and (3) shown in Fig. 18, and is therefore affected by the parasitic inductance and parasitic capacitance of the wire 42. Therefore, although there is an improvement over the structure shown in Fig. 26, there is signal loss and the characteristics of the specified impedance matching circuit 63i cannot be obtained.

[0114] In contrast, in the RF circuit module of this embodiment shown in Figures 15, 16 and 17, the path between (2) and (3) shown in Figure 18 is formed by the inter-circuit connection wiring 32. The parasitic inductance and parasitic capacitance occurring in this inter-circuit connection wiring 32 are small. Therefore, the signal loss is small, and the desired characteristics of the impedance matching circuit 63i can be obtained.

[0115] Fifth embodiment In the fifth embodiment, an RF circuit module having a through conductor in the first base material 10 will be illustrated.

[0116] 19 is a cross-sectional view of an RF circuit module 115 according to a fifth embodiment. In this RF circuit module 115, wiring such as vias V that lead out a circuit formed in a Si layer as a device layer to a first substrate side electrode 12 is formed in a SiO2 layer as a wiring formation layer. In addition, a heat spreader HS is formed in the vicinity of a circuit element 21 that is an HBT. This heat spreader HS is composed of multiple wiring layers made of Cu or Al and vias V made of Cu or Al that connect between the respective wiring layers. A surface conductor 52 is formed on the upper surface of the first substrate 10, and a plurality of through conductors 51 are formed between the surface conductor 52 and the heat spreader HS.

[0117] When the first substrate 10 is made of Si, the through conductor 51 is made of, for example, W (tungsten) or Cu. When the first substrate 10 is made of GaAs, the through conductor 51 can be made of, for example, Au.

[0118] According to this embodiment, heat generated by the circuit element 21, which is an HBT, can be dissipated and removed to the outside via the heat spreader HS, the through conductors 51, and the surface conductors 52 with high efficiency.

[0119] Sixth Embodiment In the sixth embodiment, an RF circuit module will be described in which the connection structure between a first circuit and a second circuit, and the connection structure of the first circuit and the second circuit to a module substrate are different from those in the examples described thus far.

[0120] 20 is a schematic front view of an RF circuit module 116A according to the sixth embodiment. A first circuit 10C is formed on a surface of a first substrate 10, and a second circuit 20C is formed on a surface of a second substrate 20.

[0121] Module substrate 90 has module substrate side electrodes 93 formed thereon, which are electrodes for connecting components.

[0122] The first circuit 10C or the second circuit 20C includes a high-frequency amplifier circuit that amplifies a high-frequency signal. The other circuit in which the high-frequency amplifier circuit is configured includes a control circuit that controls the operation of the high-frequency amplifier circuit. For example, the second circuit 20C includes the high-frequency amplifier, and the first circuit 10C includes the control circuit. This "high-frequency amplifier circuit" corresponds to, for example, the high-frequency amplifier 60 shown in FIG. 18, and the "control circuit" corresponds to, for example, the high-frequency amplifier control circuit 61 shown in FIG. 18.

[0123] The second base material 20 and the first base material 10 overlap with one being contained within the other in a plan view of the module substrate 90. In the example shown in Fig. 20, the second base material 20 overlaps with the first base material 10 with the second base material 20 being contained within the first base material 10.

[0124] A conductor layer constituting the inter-circuit connection wiring 32 electrically connecting the first circuit 10C and the second circuit 20C is formed from the second substrate 20 on which the second circuit 20C is formed to the first substrate 10 on which the first circuit 10C is formed. In other words, the first substrate 10 and the second substrate 20 have a conductor layer constituting the inter-circuit connection wiring 32 electrically connecting the first circuit 10C and the second circuit 20C without going through the module substrate 90.

[0125] The conductor layer constituting the inter-circuit connection wiring 32 is made of the same layer as the conductor layer constituting the first circuit 10C or the second circuit 20C. That is, a part of the conductor layer constituting the inter-circuit connection wiring 32 is in the same layer as the conductor layer constituting the first circuit 10C, and a part of the conductor layer constituting the inter-circuit connection wiring 32 is in the same layer as the conductor layer constituting the second circuit 12C.

[0126] With this structure, a part of the first circuit 10C and a part of the second circuit 20C are electrically connected, and the electrically connected part is electrically connected to the module board side electrode 93 via the wire 41.

[0127] 21 is a front view of another RF circuit module 116B according to the sixth embodiment. A first circuit 10C is formed on a surface of a first substrate 10, and a second circuit 20C is formed on a surface of a second substrate 20.

[0128] In this RF circuit module 116B, a surface conductor 52 is formed on the lower surface of the first base material 10, and a plurality of through conductors 51 are formed between this surface conductor 52 and the first circuit 10C. The other configuration is similar to that of the RF circuit module 116A. According to the RF circuit module 116B, heat generated by the first circuit 10C can be dissipated and discarded to the outside via the through conductors 51 and the surface conductor 52 with high efficiency.

[0129] Seventh embodiment In the seventh embodiment, an RF circuit module in which a first base material and a second base material are mounted on a module substrate with a first circuit and a second circuit facing the module substrate will be illustrated.

[0130] 22 is a front view of an RF circuit module 117A according to the seventh embodiment. A first circuit 10C is formed on a surface of the first substrate 10, and a second circuit 20C is formed on a surface of the second substrate 20.

[0131] The first circuit 10C of the first base material 10 and the second circuit 20C of the second base material 20 face the surface of the module substrate 90 on which the electrodes are formed.

[0132] The first base material 10 has conductor pillar bumps PB1A, PB1B connected to electrodes of the module substrate 90. The conductor pillar bump PB1B is in direct contact with a conductor layer constituting the inter-circuit connection wiring 32. The conductor pillar bumps PB1A, PB1B correspond to the "conductor protrusion" according to the present invention. This structure shortens the connection path between a part of the first circuit 10C and a part of the second circuit 20C, and also shortens the connection path between the first circuit 10C and the second circuit 20C and the electrodes of the module substrate 90. Therefore, the connection path can have lower impedance and lower inductance than a conventional structure in which a connection is made using a wire.

[0133] The first circuit 10C or the second circuit 20C includes a high-frequency amplifier circuit that amplifies a high-frequency signal. The other circuit in which the high-frequency amplifier circuit is configured includes a control circuit that controls the operation of the high-frequency amplifier circuit. For example, the second circuit 20C includes the high-frequency amplifier, and the first circuit 10C includes the control circuit. This "high-frequency amplifier circuit" corresponds to, for example, the high-frequency amplifier 60 shown in FIG. 18, and the "control circuit" corresponds to, for example, the high-frequency amplifier control circuit 61 shown in FIG. 18.

[0134] The second base material 20 and the first base material 10 overlap with one being contained within the other in a plan view of the module substrate 90. In the example shown in Fig. 22, the second base material 20 overlaps with the first base material 10 with the second base material 20 being contained within the first base material 10.

[0135] A conductor layer constituting inter-circuit connection wiring 32 electrically connecting the first circuit 10C and the second circuit 20C is formed from the second substrate 20 on which the second circuit 20C is formed to the first substrate 10 on which the first circuit 10C is formed.

[0136] With this structure, a portion of the first circuit 10C and a portion of the second circuit 20C are electrically connected via the inter-circuit connection wiring 32, and a portion of the first circuit 10C and a portion of the second circuit 20C are electrically connected to an electrode of the module substrate via the conductive pillar bump PB1.

[0137] 23 is a front view of another RF circuit module 117B according to the seventh embodiment. A first circuit 10C is formed on a surface of a first substrate 10, and a second circuit 20C is formed on a surface of a second substrate 20.

[0138] The first circuit 10C of the first substrate 10 and the second circuit 20C of the second substrate 20 face the electrode formation surface of the module substrate 90. The first substrate 10 has conductive pillar bumps PB1A and PB1B connected to the electrodes of the module substrate 90. In addition, the second substrate 20 has a conductive pillar bump PB2 connected to the electrode of the module substrate 90.

[0139] The conductor pillar bump PB2 is in direct contact with the conductor layer constituting the inter-circuit connection wiring 32. This structure shortens the connection path between a part of the first circuit 10C and a part of the second circuit 20C, and also shortens the connection path between the first circuit 10C and the second circuit 20C and the electrodes of the module substrate 90. In particular, the connection path between the second circuit 20C and the electrodes formed on the module substrate 90 can be made shorter. Therefore, the connection path can have lower impedance and lower inductance than in a conventional structure in which a connection is made using a wire.

[0140] Finally, the above-described embodiment is illustrative in all respects and is not restrictive. Modifications and changes are possible for those skilled in the art. The scope of the present invention is indicated by the claims, not the above-described embodiment. Furthermore, the scope of the present invention includes modifications from the embodiments within the scope of the claims and the equivalent scope. [Explanation of symbols]

[0141] ANT…Antenna HS…Heat spreader PB1: First conductive pillar bump PB2: Second conductive pillar bump PM…P-MOS NM...N-MOS Si-sub...Si substrate V…Via 3...PA circuit element 10...First base material 10C…1st circuit 12...First base material side electrode 13,23…Conductor pillar 14,24…Solder layer 15…Resin layer 20…Second base material 20C…Second circuit 20D…Epitaxial layer 20N…GaAs base material 21...Circuit element 22…Second base material side electrode 22U…base electrode 29…Peeling layer 31...External connection electrode (bonding pad) 32...Intercircuit connection wiring 41, 41A, 41B, 42, 43... Bonding wire 51...Through conductor 52...Surface conductor 60...High frequency amplifier 61...High frequency amplifier control circuit 62,64,65…Switch 63, 66, 69A, 69B...Impedance matching circuit 67...Low noise amplifier 68A, 68B…Duplexer 70…Antenna switch 71...Bandpass filter 85...Resist film 90...Module board 91, 92, 93...Module board side electrodes 100…Mold resin 104A, 104B...Laminate 111, 113A, 113B, 113C, 114B, 115, 116A, 116B... RF circuit modules 120…Front-end module 200…Motherboard

Claims

1. A module substrate having electrodes for mounting components; A first substrate having a first circuit formed thereon; A second substrate having a second circuit formed thereon; Equipped with the first circuit includes a control circuit that controls an operation of the second circuit; the second circuit includes a high frequency amplifier circuit that amplifies an RF signal; the second substrate is mounted to the first substrate; the first substrate is flip-chip bonded to the module substrate; the first base material and the second base material each have a conductor layer that constitutes an inter-circuit connection wiring that electrically connects the first circuit and the second circuit without passing through the module substrate; the first base material has a first base material side conductor protrusion portion connected to the electrode of the module board, the second substrate has a second substrate side conductor protrusion portion connected to the electrode of the module substrate; RF circuit module.

2. the second substrate side conductor protrusion is provided immediately adjacent to the second circuit; The RF circuit module according to claim 1 .

3. a first substrate side electrode is formed on a surface of the first substrate at a position not overlapping the second substrate; The first substrate-side conductor protrusion is connected to the first substrate-side electrode.

3. The RF circuit module according to claim 1 or 2.

4. A module substrate having electrodes for mounting components; A first substrate having a first circuit formed thereon; A second substrate having a second circuit formed thereon; Equipped with the first circuit includes a control circuit for controlling an operation of the second circuit; the second circuit includes a high frequency amplifier circuit for amplifying an RF signal; the second substrate is mounted to the first substrate; the first base material and the second base material each have a conductor layer that constitutes an inter-circuit connection wiring that electrically connects the first circuit and the second circuit without passing through the module substrate; an upper surface of the conductor layer constituting the inter-circuit connection wiring is located below an upper surface of the second circuit in a plan view of the module substrate; RF circuit module.

5. the first circuit or the second circuit has an impedance matching circuit or a part of an impedance matching circuit that matches impedance between the high frequency amplifier circuit and an input or an output of the high frequency amplifier circuit; The RF circuit module according to claim 4 .

6. the first substrate is a substrate of a single semiconductor; The second substrate is a compound semiconductor substrate.

6. The RF circuit module according to claim 1.

7. The first base material has a higher thermal conductivity than the second base material.

7. The RF circuit module according to claim 1.

8. The second substrate is thinner than the first substrate. The RF circuit module according to claim 1 .

9. The control circuit includes a switch circuit for the RF signal.

9. The RF circuit module according to claim 1.

10. the first base material includes a heat spreader configured by laminating a conductor layer and an insulator layer, and the heat spreader is disposed in the vicinity of the second circuit; The RF circuit module according to claim 1 .

11. The conductor layer constituting the inter-circuit connection wiring is made of the same layer as the conductor layer constituting the second circuit. The RF circuit module according to claim 1 .

12. the first substrate has a first substrate side conductor protrusion connected to the electrode of the module board, the second substrate has a second substrate side conductor protrusion connected to the electrode of the module substrate, the first circuit and the second circuit face an electrode formation surface of the module substrate; The RF circuit module according to claim 1 .

13. the first substrate-side conductor protrusion is in direct contact with a conductor layer constituting the inter-circuit connection wiring; The RF circuit module according to claim 12.

14. a height of the first substrate side conductor protrusion portion is smaller than a thickness of the first substrate; The RF circuit module according to claim 12 or 13.

15. A module substrate having electrodes for connecting components; a first substrate having a first circuit formed thereon and electrically connected to an electrode of the module substrate; a second substrate having a second circuit formed thereon and electrically connected to an electrode of the module substrate; Equipped with the first circuit or the second circuit includes a high-frequency amplifier circuit that amplifies a high-frequency signal, The other circuit of the circuits in which the high frequency amplifier circuit is configured includes a control circuit for controlling the operation of the high frequency amplifier circuit, the second base material and the first base material overlap each other in a plan view of the module substrate, the first base material and the second base material each have a conductor layer that constitutes an inter-circuit connection wiring that electrically connects the first circuit and the second circuit without passing through the module substrate; The conductor layer constituting the inter-circuit connection wiring is made of the same layer as the conductor layer constituting the first circuit or the second circuit. RF circuit module.

16. A module substrate having electrodes for connecting components; a first substrate having a first circuit formed thereon and electrically connected to an electrode of the module substrate; a second substrate having a second circuit formed thereon and electrically connected to an electrode of the module substrate; Equipped with the first circuit or the second circuit includes a high-frequency amplifier circuit that amplifies a high-frequency signal, The other circuit of the circuits in which the high frequency amplifier circuit is configured includes a control circuit for controlling the operation of the high frequency amplifier circuit, the second base material and the first base material overlap each other in a plan view of the module substrate, the first base material and the second base material each have a conductor layer that constitutes an inter-circuit connection wiring that electrically connects the first circuit and the second circuit without passing through the module substrate; Of the first base material or the second base material, the base material arranged adjacent to the module substrate has a through conductor that electrically connects a first surface on which a circuit is configured and a second surface that forms a pair with the first surface. RF circuit module.

17. A module substrate having electrodes for connecting components; a first substrate having a first circuit formed thereon and electrically connected to an electrode of the module substrate; a second substrate having a second circuit formed thereon and electrically connected to an electrode of the module substrate; Equipped with the first circuit or the second circuit includes a high-frequency amplifier circuit that amplifies a high-frequency signal, The other circuit of the circuits in which the high frequency amplifier circuit is configured includes a control circuit for controlling the operation of the high frequency amplifier circuit, the second base material and the first base material overlap each other in a plan view of the module substrate, the first base material and the second base material each have a conductor layer that constitutes an inter-circuit connection wiring that electrically connects the first circuit and the second circuit without passing through the module substrate; the first base material or the second base material has a conductor protrusion portion connected to an electrode of the module substrate, and the first circuit of the first base material and the second circuit of the second base material face a surface of the module substrate on which the electrode is formed. RF circuit module.

18. the conductor protrusion is in direct contact with a conductor layer constituting the inter-circuit connection wiring; The RF circuit module according to claim 17.

19. a height of the conductor projection provided on one of the first base material and the second base material which includes the other in a plan view of the module substrate is smaller than a thickness of the first base material; 19. The RF circuit module according to claim 17 or 18.

20. A method for manufacturing an RF circuit module including: a module substrate having electrodes for mounting components; a first substrate having a first circuit including a control circuit; and a second substrate having a second circuit including a high-frequency amplifier circuit controlled by the control circuit, the method comprising the steps of: forming the first circuit and an inter-substrate connection conductor on the first substrate, the single-piece semiconductor substrate; forming a semiconductor thin film having the second circuit and an inter-substrate connection conductor on a compound semiconductor substrate, which is the second substrate, via a release layer; removing the release layer by etching to release the semiconductor thin film from the compound semiconductor substrate to form the second substrate; a step of joining the second base material to a predetermined position of the first base material to connect the inter-base material connection conductor of the first base material to the inter-base material connection conductor of the second base material, thereby forming a laminate of the first base material and the second base material; forming a first substrate-side conductor projection connected to the first circuit and a second substrate-side conductor projection connected to the second circuit; mounting the laminate on the module substrate by connecting the first substrate-side conductor projections and the second substrate-side conductor projections to the electrodes of the module substrate; A method for manufacturing an RF circuit module having the above structure.

21. A method for manufacturing an RF circuit module including: a module substrate having electrodes for mounting components; a first substrate having a first circuit including a control circuit; and a second substrate having a second circuit including a high-frequency amplifier circuit controlled by the control circuit, the method comprising the steps of: forming the first circuit on the first substrate, which is a free-standing semiconductor substrate; forming a semiconductor thin film having the second circuit on a compound semiconductor substrate, which is the second substrate, via a release layer; removing the release layer by etching to release the semiconductor thin film from the compound semiconductor substrate to form the second substrate; a step of joining the second base material to a predetermined position of the first base material to form a laminate of the first base material and the second base material; forming an inter-substrate connection conductor connecting the first circuit and the second circuit; mounting the laminate on the module substrate; A method for manufacturing an RF circuit module having the above structure.

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