JP6135485B2 - High frequency module - Google Patents

Description

  The present invention relates to a high frequency module.

  Conventionally, a semiconductor element is mounted on one side of a resin base, the other side of the resin base is placed on a stiffener, and one side of the resin base is connected to an antenna module via an aluminum waveguide adapter. Modules are known (see, for example, Patent Document 1).

  Further, there is a high-frequency module for a radar apparatus in which an RF substrate on which semiconductor elements such as a mixer and an oscillator are mounted is surface-connected to one surface of the RF chassis, and the other surface of the RF chassis is surface-connected to the antenna chassis and the antenna substrate ( For example, see Patent Document 2).

JP 2006-261767 A JP 2013-79890 A

  Since the conventional high-frequency module connects a resin substrate (a substrate made of a resin base material or an RF substrate) on which a semiconductor element is mounted to an antenna, the resin substrate and the antenna are separated from each other between the resin substrate and the antenna. A metal plate such as a metal waveguide adapter or an RF chassis has been disposed. This type of metal plate is formed from a metal processed part obtained by machining a metal by aluminum die casting, cutting or the like. In general, this type of metal plate has a high component price, and accordingly, there is a problem that the component price of the high-frequency module increases accordingly.

  Further, when a gap is generated in the joint surface between the metal plate and the resin substrate, radio waves leak from the waveguide formed on the metal plate. In order to prevent leakage of the radio wave, an electromagnetic shielding space is formed to cover the semiconductor element and the plurality of waveguides mounted on the surface of the resin substrate, and the metal plate is bonded to the resin substrate on the outer wall of the electromagnetic shielding space. Adhere to. For this purpose, it is necessary to provide a special mechanism such as a rubber member, a screw, and an adhesive for pressing the resin substrate against the metal plate from the back side of the resin substrate. There was a problem of becoming. In addition, the high-frequency module described in Patent Document 2 has a structure in which an antenna substrate is attached to the upper surface of a metal plate and a resin substrate is attached to the back surface of the metal plate. Here, since the outer dimension of the antenna substrate is increased so as to obtain an antenna having a required gain, the outer dimension of the metal plate is increased in accordance with the antenna substrate. The outer portion of the metal plate is fixed with a screw, and the outer wall of the electromagnetic shielding space for housing the semiconductor element presses the joint surface with the resin substrate with a rubber member, thereby bringing the metal plate and the resin substrate into close contact with each other. At this time, since the outer dimension of the metal plate to be screwed is larger than the dimension of the outer wall of the electromagnetic shielding space that houses the semiconductor element, and the outer wall of the electromagnetic shielding space is pressed by the rubber member, the outer wall of the electromagnetic shielding space There is a problem that the adhesion strength between the resin substrate and the resin substrate is weakened, the performance of suppressing radio wave leakage is deteriorated, and the electrical characteristics of the high-frequency module are deteriorated.

  The present invention has been made to solve such problems, and a separate metal plate in which an electromagnetic shielding space for housing a semiconductor element is formed is sandwiched between a semiconductor element mounted on a resin substrate and an antenna. The object is to construct a high-frequency module with no structure.

  A high-frequency module according to the present invention includes a semiconductor element, a plurality of antenna elements, a microstrip line connected to the antenna element, and a converter that performs signal connection between the microstrip line and the waveguide. An antenna substrate having the antenna substrate is bonded to the front surface, the semiconductor element is bonded to the back surface, and a waveguide is formed on the inner layer. The microstrip line and the microstrip line and the waveguide are formed on the back surface. A resin substrate provided with a converter for performing signal connection between the resin substrate and a cover substrate bonded to the back surface of the resin substrate and containing the semiconductor element together with the resin substrate, and a waveguide of the resin substrate Are arranged so as to connect the converter of the resin substrate and the converter of the antenna substrate vertically to the substrate surface.

  According to the present invention, a separate metal plate in which an electromagnetic shielding space for housing a semiconductor element is formed is provided with a cheaper structure that is not sandwiched between a semiconductor element mounted on a resin substrate and an antenna. External leakage of radio waves generated from the microstrip line can be shielded.

1 is a diagram showing a configuration of a high-frequency module according to Embodiment 1. FIG. 1 is a cross-sectional view illustrating a configuration of a high frequency module according to Embodiment 1. FIG. It is a figure which shows the structural example which joined the cover board | substrate formed with the metal by Embodiment 1 to the resin substrate. It is a figure which shows the other structural example which joined the cover board | substrate formed with the metal by Embodiment 1 to the resin substrate.

Embodiment 1 FIG.
1A and 1B are diagrams showing the configuration of a high-frequency module according to Embodiment 1 of the present invention, in which FIG. 1A is a top view of the high-frequency module, and FIG. 1B is a bottom view of the high-frequency module. 2A and 2B are diagrams showing the configuration of the high-frequency module according to Embodiment 1, wherein FIG. 2A is a cross-sectional view taken along line AA of the high-frequency module, FIG. It is sectional drawing.

  1 and 2, the high-frequency module according to the first embodiment includes a resin substrate 1, an antenna substrate 2, a cover substrate 3, a conductive connection member 50, a semiconductor component 6 made of semiconductor elements, and an electronic component 7. It is prepared for. The antenna substrate 2 is bonded to the front surface (upper surface) of the resin substrate 1 by an adhesive. The cover substrate 3 is bonded to the back surface (lower surface) of the resin substrate 1 by a plurality of conductive bonding members 50. The semiconductor component 6 and the electronic component 7 are attached to the back surface (lower surface) of the resin substrate 1 and mounted on the back surface. The conductive connection member 50 is made of a solder bump, a gold bump, or the like. The resin substrate 1 and the cover substrate 3 are bump-bonded by a plurality of conductive connection members 50.

  The resin substrate 1 is composed of a multilayer printed wiring board made of resin such as glass epoxy resin or polyimide resin. Ground conductors 27 and 71 are formed on the surface of the dielectric 20 on the surface side of the resin substrate 1. A wiring circuit pattern to which the semiconductor component 6 and the electronic component 7 are connected and a ground conductor 52 are formed on the surface of the dielectric 11 on the back surface side of the resin substrate 1. A ground conductor 70 is formed on the inner layer of the resin substrate 1. The semiconductor component 6 includes a high-frequency semiconductor element that processes a high-frequency RF (Radio Frequency) signal such as a millimeter wave or a microwave, and a circuit is formed of, for example, a SiGe (silicon germane) semiconductor. The semiconductor component 6 includes a receiving (RX) chip and a transmitting (TX) chip. The receiving semiconductor component 6 (RX) is composed of a high-frequency semiconductor element such as an amplifier or a mixer (frequency mixing circuit). The semiconductor component 6 (TX) for transmission is composed of high-frequency semiconductor elements such as an amplifier, a power distributor, and an oscillator. The electronic component 7 includes a microcomputer, a memory, a system IC, an AD converter, a DA converter, a capacitor, a resistor, and the like. The electronic component 7 performs FFT (Fast Fourier Transform), radar signal processing, power transformation processing, and the like. In the resin substrate 1, a plurality of waveguides 13 are formed in the inner layer between the ground conductor 27 on the front surface side of the resin substrate 1 and the back surface of the dielectric 11 on the back surface side. That is, the opening hole above the waveguide 13 is blocked by the antenna substrate 2, and the opening hole below the waveguide 13 is blocked by the dielectric 11. A converter 14 and transmission lines 18 and 19 are formed on the back side of the resin substrate 1. The transmission lines 18 and 19 are each constituted by a microstrip line. The transmission line 19 is connected to the converter 14 and to the semiconductor component 6. The semiconductor component 6 is connected to the wiring pattern 17 by flip chip connection via a plurality of conductive connection members 61. The conductive connection member 61 is made of a gold bump. The transmission semiconductor component 6 (TX) and the reception semiconductor component 6 (RX) are connected by a transmission line 18. A plurality of conductive connection members 50 are disposed on the ground conductor 52 of the resin substrate 1. A solder non-joining region with poor solder adhesion is formed around the ground conductor 52 with which the conductive connecting member 50 contacts. The plurality of conductive connection members 50 are arranged so as to surround the converter 14. The RF signal transmitted through the waveguide 13 is connected to the converter 14. The ground conductor 27 on the surface of the resin substrate 1, the ground conductor 70 on the inner layer of the resin substrate 1, and the ground conductor 52 on the back surface are connected by the conductor via 12.

  The antenna substrate 2 is formed of a dielectric 20 such as a fluororesin substrate made of polytetrafluoroethylene (PTFE) or a liquid crystal polymer (Liquid Crystal Polymer) substrate. The plurality of antenna elements 21, the plurality of feed lines 23, and the plurality of converters 25 are formed on the surface (upper surface) of the dielectric 20 of the antenna substrate 2 to constitute an array antenna including a plurality of subarray antennas 26. . The subarray antenna 26 is provided with one or a plurality of channels for transmission and a plurality of channels for reception. FIG. 1 shows an example in which a power supply system of one channel for transmission and two channels for reception is provided. For example, a radar transmission radio wave is radiated from the transmission subarray antenna 26. In addition, the reception subarray antennas 26 for two channels receive the radio waves transmitted from the radar, reflected by the target, and transmitted back to the converter 14 via the waveguide 13. The received signal transmitted to the converter 14 is subjected to signal processing such as low noise amplification, filtering, frequency mixing processing, etc. in the receiving semiconductor component 6 (RX), and then in the radar signal processing electronic component 7. The detected signal is subjected to radar signal processing such as distance measurement processing and angle measurement processing. Each of the plurality of antenna elements 21 is connected to the feed line 23. The feed line 23 is connected to the converter 25. The plurality of antenna elements 21 are connected to the converter 25 via the feed line 23. The feed line 23 is configured by a microstrip line. The converters 25 are provided for the number of transmission channels and the number of reception channels. The converter 25 includes a power supply terminal 24 and a shield plate 22. The feed terminal 24 is formed at the end of the feed line 23. The shield plate 22 is formed of a conductor plate in which a concave cut is formed. The power supply terminal 24 is disposed in a non-contact manner inside the cutout of the shield plate 22, and the periphery is surrounded by the conductive surface of the shield plate 22. The power supply terminal 24 is electromagnetically coupled to the waveguide 13 through the notch of the shield plate 22. Thereby, the waveguide 13 connects between the converter 14 on the back surface of the resin substrate 1 and the converter 25 on the surface of the antenna substrate 2 perpendicularly to the substrate surface (the front surface or the back surface of the resin substrate 1). That is, an RF signal is transmitted between the converter 14 and the converter 25 via the waveguide 13. The ground conductor 22 on the front surface of the antenna substrate 2 and the ground conductor 27 on the back surface are connected by a conductor via 28.

  The cover substrate 3 is composed of a dielectric 30 made of resin such as glass epoxy resin or polyimide resin. A ground conductor 32 is formed on the surface of the dielectric 30 of the cover substrate 3. A ground conductor 31 is formed on the back surface of the dielectric 30 of the cover substrate 3. The ground conductor 32 on the front surface of the cover substrate 3 and the ground conductor 31 on the back surface are connected by a conductor via 33. By connecting the front surface (upper surface) of the cover substrate 3 to the back surface (lower surface) of the resin substrate 1 through the plurality of conductive connection members 50, the resin substrate 1, the cover substrate 3, and the plurality of conductive connection members 50, An electromagnetic shielding space 100 surrounded by the ground plane is formed. As a result, the semiconductor component 6 can be housed in the electromagnetic shielding space 100 surrounded by the ground surface between the resin substrate 1 and the cover substrate 3, so that external leakage of radio waves generated from the semiconductor component 6 is shielded. can do.

  In addition, the plurality of conductive connection members 50 are arranged between the semiconductor component 6 (TX) for transmission and the semiconductor component 6 (RX) for reception, so that the semiconductor component 6 (TX) for transmission and the reception are received. Electromagnetic interference between the semiconductor components 6 (RX) can be prevented. At this time, some of the two conductive connection members 50 (the conductive connection member 501 and the conductive connection member 502) have a transmission semiconductor component 6 (TX) and a reception semiconductor component 6 ( RX) is connected. The distance between the conductive connecting member 501 and the conductive connecting member 502 is smaller than a quarter of the signal propagation wavelength λ of the RF signal in the transmission line 18.

  As described above, in the high-frequency module shown in FIGS. 1 and 2, a metal plate separate from the resin substrate 1 and the antenna substrate 2 is provided between the semiconductor element mounted on the resin substrate 1 and the antenna substrate 2. The semiconductor element can be accommodated in the electromagnetic shielding space 100. For this reason, since there is no separate metal plate having a high component price, the component price of the entire high-frequency module can be further reduced as compared with the conventional high-frequency modules disclosed in Patent Documents 1 and 2. In addition, since the electromagnetic shielding space surrounding the semiconductor element is formed by the bump bonding of the resin substrate 1 and the cover substrate 3, the adhesion force of the bonding surface becomes strong, and radio wave leakage from the bonding surface can be suppressed. Therefore, it is possible to prevent deterioration of electrical characteristics of the high frequency module.

The cover substrate may be composed of a metal plate formed by machining a metal.
FIG. 3 is a diagram illustrating a configuration example of another aspect in which a cover substrate 301 formed of a metal material is bonded to the resin substrate 1. In FIG. 3, the cover substrate 301 is formed of a metal material having a small difference in linear expansion coefficient from the resin substrate. The cover substrate 301 is formed with a solder joint portion 302 with improved solder adhesion. Between adjacent solder joints 302, a groove or a solder non-joint region with poor solder adhesion is formed. The solder joint portion 302 of the cover substrate 301 is connected to the conductive connection member 50 and joined to the resin substrate 1 via the conductive connection member 50. An electromagnetic shielding space 105 surrounding the semiconductor component 6 is formed by the cover substrate 301, the plurality of conductive connection members 50, and the ground conductor 70 of the resin substrate 1. As a result, like the cover substrate 3 shown in FIGS. 1 and 2, the semiconductor component 6 is accommodated in the electromagnetic shielding space 105 without providing a metal plate separate from the resin substrate 1 and the antenna substrate 2. Can do.

  FIG. 4 is a diagram showing another configuration example of another aspect in which the cover substrate 310 formed of metal is bonded to the resin substrate 1. In FIG. 4, a cover substrate 310 is a metal case formed by sheet metal processing, extrusion molding, cutting processing, aluminum die casting, or the like, and is formed of, for example, a hexahedron having an opening on one surface. The cover substrate 310 has an outer wall that forms a part of the electromagnetic shielding space 110 that houses the semiconductor component 6. An electromagnetic shielding space 105 surrounding the semiconductor component 6 is formed by the cover substrate 310 and the ground conductor 70 of the resin substrate 1. The cover substrate 310 is bonded to the ground conductor 52 of the resin substrate 1 by solder bonding. Thus, like the cover substrate 3 shown in FIG. 1 and FIG. 2, the metal plate separate from the resin substrate 1 and the antenna substrate 2 is inserted between the resin substrate 1 and the antenna substrate 2 without being inserted between the semiconductor substrate 1 and the antenna substrate 2. The component 6 can be stored in the electromagnetic shielding space 105. Compared to the RF chassis disclosed in Patent Document 2, the cover substrate 310 can be configured with a smaller metal case.

  As described above, the high-frequency module according to Embodiment 1 includes a semiconductor element (semiconductor component 6), a plurality of antenna elements 21, and a microstrip line (transmission line 23) connected to the antenna element 21. The antenna substrate 2 having a converter 25 that performs signal connection between the microstrip line (transmission line 23) and the waveguide 13 and the antenna substrate 2 are joined to the surface, and the semiconductor element (semiconductor component 6). ) Is bonded to the back surface, and a waveguide 13 is formed on the inner layer, and a signal connection is made between the microstrip line (transmission line 23) and the microstrip line (transmission line 23) and the waveguide 13 on the back surface. And the semiconductor element (semiconductor component) together with the resin substrate 1 and bonded to the back surface of the resin substrate 1. ), And the waveguide 13 of the resin substrate 1 is perpendicular to the substrate surface between the converter 14 of the resin substrate 1 and the converter 25 of the antenna substrate 2. It is arranged to be connected.

  As a result, a separate metal plate in which an electromagnetic shielding space for housing a semiconductor element is formed is a less expensive structure that does not sandwich the semiconductor element mounted on the resin substrate and the antenna, and the semiconductor element or microstrip line It is possible to shield the external leakage of radio waves generated from the. Further, since the semiconductor element is mounted on the back surface of the resin substrate 1 and is not mounted on the cover substrate 3, the wiring circuit pattern of the cover substrate 3 can be configured more easily and inexpensively.

  Further, the cover substrate may be bonded to the back surface of the resin substrate 1 by a plurality of conductive bonding members 50.

  Further, the cover substrate may be constituted by cover substrates 301 and 310 formed of a metal material.

  DESCRIPTION OF SYMBOLS 1 Resin board | substrate, 2 Antenna board | substrate, 3 Cover board | substrate, 6 Semiconductor component, 7 Electrical component, 13 Waveguide, 14 Converter, 23 Transmission line, 25 Converter, 50 Conductive connection member, 61 Conductive connection member, 301 Cover substrate, 310 cover substrate.

Claims (2)

A semiconductor element;
Resin in which the semiconductor element is bonded to the back surface, a waveguide is formed in the inner layer, and a microstrip line and a converter for signal connection between the microstrip line and the waveguide are provided on the back surface A substrate,
A plurality of arrayed antenna elements joined to the surface of the resin substrate, a microstrip line connected to the antenna element, and a converter for performing signal connection between the microstrip line and the waveguide of the resin substrate An antenna substrate having
A cover substrate formed of a metal material, which is bonded to the back surface of the resin substrate and houses the semiconductor element together with the resin substrate;
The waveguide of the resin substrate is a high-frequency module arranged so as to vertically connect between the converter of the resin substrate and the converter of the antenna substrate.   The high frequency module according to claim 1, wherein the cover substrate is bonded to the back surface of the resin substrate by a plurality of conductive bonding members.

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