JP2013258535A - Mounting structure and high frequency circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem wherein an impedance of a resistor viewed from a high frequency signal on a transmission line having the resistor presents a capacitive reactance.SOLUTION: An embodiment provides a mounting structure 1 including: a conductive plate 13 having a ground surface; a dielectric substrate 3 disposed on the plate 13 which has a reverse surface on the ground surface side of the plate 13 and a principal surface opposite to the reverse surface; a line conductor 30 disposed on the principal surface of the substrate 3 which constitutes a micro strip line with the substrate 3 and the plate 13; an insulating foundation 31 disposed on the substrate 3 in an insulated relationship to the line conductor 30; and a resistor 7 disposed on the foundation 31 in a spaced relationship to the ground surface of the plate 13 by a dimension greater than a substrate thickness of the substrate 3 by a foundation height of the foundation 31, and connected to the line conductor 30.

Description

  One embodiment relates to a mounting structure and a high-frequency circuit device.

  A Wilkinson circuit is known as an example of the arrangement of resistors used in a high-frequency circuit. For example, a large power distributor / synthesizer in which the stray capacitance of a resistor connected between two distributed constant lines is reduced is known. (See Patent Document 1).

  Also, resistors are used for various purposes such as isolation resistance between distributed constant lines and attenuator resistance of high frequency power, and a structure for reducing the parasitic capacitance of this resistor is known (for example, see Patent Document 2). ). The parasitic capacitance of the resistor means a ground capacitance with respect to the ground of the resistor.

JP 2000-77873 A Japanese Patent Laid-Open No. 9-232819 Japanese Patent Laid-Open No. 2003-77945 JP 2001-244420 A

  However, when viewed from a signal on a transmission line having a resistor in a high-frequency circuit, the impedance of the resistor may exhibit a capacitive reactance. For a high-frequency signal, there is a case where the resistor does not appear to be purely resistive, and this resistor behaves as an element exhibiting capacitance. If a resistor consisting only of a pure resistance component is connected to a transmission line with characteristic impedance, if the load impedance of this resistor shifts to the capacitive reactance region due to the characteristics, the high-frequency characteristics of this transmission line will deteriorate, It has a big influence on the performance of the circuit.

  In order to solve such a problem, according to one embodiment, the plate includes a conductive plate having a ground surface, a back surface of the plate on the ground surface side, and a main surface opposite to the back surface. A dielectric substrate provided above, and a microstrip line together with these substrate and plate, a line conductor provided on the main surface of the substrate, and insulated from the line conductor and provided on the substrate An insulating base provided on the base, and a resistor connected to the line conductor and spaced apart from the ground plane of the plate with a size larger than the substrate thickness of the base by the base height of the base. A mounting structure is provided.

  According to another embodiment, a conductive plate having a ground plane, a high-frequency semiconductor element grounded on the plate, a wall body surrounding the high-frequency semiconductor element, and a plurality of through conductors passing through the wall body And a package having a lid for sealing the space containing the high-frequency semiconductor element on the wall, and at least one of the input and output of the high-frequency semiconductor element is provided on the plate in the package. A dielectric substrate having a back surface on the ground surface side and a main surface opposite to the back surface, and a line on the substrate that forms a microstrip line together with the substrate and the plate and is electrically connected to the through conductor A conductor, an insulating base insulated from the line conductor and provided on the board; and a base of the board provided on the foundation by a height of the foundation. Spaced apart from the ground plane of the plate with a dimension greater than the thickness, the high-frequency circuit device is provided; and a resistor connected to the line conductor.

1 is an exploded perspective view of a high-frequency circuit device according to a first embodiment including a mounting structure according to the first embodiment. It is a figure which shows the longitudinal cross-section of the high frequency circuit apparatus which concerns on 1st Embodiment. It is a figure which shows an example of the mounting structure which concerns on 1st Embodiment. It is a longitudinal section of the mounting structure concerning a 1st embodiment. It is a longitudinal cross-sectional view of the mounting structure which concerns on the modification of 1st Embodiment. It is a longitudinal cross-sectional view of the mounting structure which concerns on 2nd Embodiment.

  Hereinafter, the mounting structure and the high-frequency circuit device according to the embodiment will be described with reference to FIGS. 1 to 6. In the drawings, the same portions are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is an exploded perspective view of a high-frequency circuit device including a mounting structure according to the first embodiment. FIG. 2 is a view showing a longitudinal sectional structure taken along line I-II of the high-frequency circuit device according to the present embodiment. In these drawings, elements having the same reference numerals represent the same elements.

  The high-frequency circuit device 10 is a microwave power amplifier, and includes a conductive plate 13 having a ground plane, a semiconductor element 24 (high-frequency semiconductor element) grounded on the plate 13, and a frame-like wall surrounding the semiconductor element 24. A package 12 having a body 12, two through-input conductors 16 and 18 passing through the wall body 12, and a lid 11 for sealing a space including the semiconductor element 24 on the wall body 12, and a semiconductor element in the package 2 A dielectric substrate 3 provided on the plate 13 on the input side 24 and having a back surface on the grounding surface side of the plate 13 and a main surface opposite to the back surface, and on the plate 13 on the output side of the semiconductor element 24 And a dielectric substrate 4 having a back surface provided with a plate ground and a main surface opposite to the back surface. The high-frequency circuit device 10 is disposed so as to face another dielectric substrate 5 provided on the plate 13 between the substrate 3 and the semiconductor element 24, with the substrate 5 and the semiconductor element 24 interposed therebetween. 4 and a dielectric substrate 6 provided on the plate 13.

  Further, the high-frequency circuit device 10 constitutes a power branch circuit 25 (microstrip line) together with the substrate 3 and the plate 13, and the line conductor 30 on the substrate 3 electrically connected to the through conductor 16 of the package 2, 4 and the plate 13 constitute a power combining circuit 26 (microstrip line), and are provided between the line conductor 33 on the substrate 4 electrically connected to the through conductor 18, the power branch circuit 25 and the semiconductor element 24. The input impedance matching circuit 27 and the output impedance matching circuit 28 provided between the power combining circuit 26 and the semiconductor element 24 are provided.

  Further, the high-frequency circuit device 10 includes an insulating base 31 that is insulated from the line conductor 30 on the input side of FIG. And a resistor 7 connected to the line conductor 30 with a dimension larger than the substrate thickness and spaced from the plate ground plane. The high-frequency circuit device 10 has an insulating base 34 that is insulated from the line conductor 33 on the output side and is provided on the substrate 4, and a base plate thickness of the base 34 that is provided on the base 34. And a resistor 8 connected to the line conductor 33 with a large dimension and spaced from the plate ground plane.

  The plate 13 is a metal base plate, and is fastened and fixed to a conductive metal case (not shown) with four screws through four notches 50.

  The semiconductor element 24 is a high-frequency power amplifier having one or more field effect transistors (FETs). The semiconductor element 24 amplifies two signals output from the input impedance matching circuit 27. The semiconductor element 24, the input impedance matching circuit 27, and the output impedance matching circuit 28 are connected by a bonding wire 29.

  The package 2 hermetically seals a space including the semiconductor element 24, the input impedance matching circuit 27, the output impedance matching circuit 28, and the like. As shown in FIG. 2, the package 2 includes a dielectric 22 on the left side, another dielectric 21 provided on the dielectric 22, a wall body 12 standing on the dielectric 21, and a dielectric 23 on the right. The other dielectric 21 on the dielectric 23 and the opposing wall 12 standing on the dielectric 21 are provided. The lid 11 is fixed on a wall body 12 having a four-sided wall shape via a metal sealing material 20. The package 2 may be opened at the bottom, and the semiconductor element 24 may be directly grounded on the plate 13. In a state where the semiconductor element 24, the input impedance matching circuit 27, and the like are recessed in the package 2, the wall 12 surrounds the periphery of the semiconductor element 24, the input impedance matching circuit 27, and the like. The wall body 12 forming two pairs of standing walls is a metal member or dielectric member covered with a metal. Openings extending in the horizontal direction are formed in the lower portions of these wall bodies 12, and dielectrics 21 and 21 are arranged as plugs in the openings, respectively, so that the airtightness of the internal space is maintained. .

  The package 2 includes feedthrough portions 14 and 15 for transmitting signal power to the inside and outside of the space in the package 2 on the input / output side on the plate 13. The feedthrough portion 14 includes a dielectric 22 on the plate 13 and a through conductor 16 that is provided on the dielectric 22 and penetrates the dielectric 21 below the wall 12. The plate 13, the dielectric 22 and the through conductor 16 constitute a microstrip line. An input terminal 17 extending outward from the space in the wall 2 is connected to the through conductor 16 by solder bonding. The feedthrough portion 15 includes a dielectric 23 on the plate 13 and a through conductor 18 that is provided on the dielectric 23 and penetrates another dielectric 21 below the wall 12. The plate 13, the dielectric 23, and the through conductor 18 constitute a microstrip line. An output terminal 19 extending outward from the space defined by the wall 12 and the lid 11 is connected to the through conductor 18 by solder bonding.

  The substrates 3, 4, 5, and 6 are all provided on the ground of the plate 13, and all have substantially the same substrate width. The substrate width refers to a direction orthogonal to the substrate length direction, which is the propagation direction of signal power, on the main surface. The substrate 3, the substrate 5, the substrate 6 and the substrate 4 are juxtaposed in the substrate length direction in this order.

  The power branch circuit 25 is a microstrip line that distributes signal power from the input terminal 17. The line conductor 30 constituting the power branch circuit 25 has a branched conductor pattern surface with one input and two outputs so that the power of the input signal is branched into two. The line conductor 30 is formed by patterning after a metal film is formed on the main surface of the substrate 3, for example. The power branch circuit 25 and the through conductor 16 are connected by a bonding wire 29. The power branch circuit 25 may include a stub and a λ / 4 transmission line. λ represents one wavelength of the microwave signal on the line conductor 30.

  The base 31 is fixed on the substrate surface between the branched conductor pattern surfaces of the line conductor 30.

  FIG. 3 is a diagram showing a mounting structure example according to the present embodiment, and only the power branch circuit 25 alone is extracted and displayed. The above described symbols represent the same elements. The mounting structure 1 comprises a plate 13 having a ground plane, a dielectric substrate 3 provided on the plate 13, and a power branch circuit 25 (microstrip line) together with the substrate 3 and the plate 13. A line conductor 30 provided on the main surface of the substrate, an insulating base 31 insulated from the line conductor 30 and provided on the substrate 3, and a substrate height of the substrate 3 provided on the base 31. And a resistor 7 connected to the line conductor 30 with a dimension larger than the thickness and spaced from the plate ground surface.

  The base 31 has, for example, a rectangular parallelepiped shape. The base 31 is provided in an area different from the area where the line conductor 30 is formed. As the shape of the base 31, various shapes such as a trapezoidal shape or a shape protruding upward from the main surface of the substrate 3 may be used. It is sufficient that the base 31 supports the resistor 7 while being separated from the grounding surface of the plate 13. The base 31 may be composed of a plurality of pedestals. For example, a plurality of pedestals each having a convex shape or an island shape are formed on the substrate 3 and bridged between these pedestals like bridge piers. A resistor 7 may be provided.

  The resistor 7 is an isolation resistor that constitutes a Wilkinson power combining circuit. The resistor 7 is connected to each branch pattern of the line conductor 30 by a bonding wire 32. A thin film resistor is used for the resistor 7.

  The power combining circuit 26 in FIGS. 1 and 2 is a microstrip line that combines the amplified signals from the output impedance matching circuit 28. The line conductor 33 constituting the power combining circuit 26 has a two-input and one-output constricted conductor pattern surface, and synthesizes the branched signals amplified for each FET cell of the semiconductor element 24. For example, the line conductor 33 is formed by patterning after a metal film is formed on the main surface of the substrate 4. The power combining circuit 26 and the through conductor 18 are connected by a bonding wire 29. The power combining circuit 26 may include a stub and a λ / 4 transmission line.

  The base 34 is fixed on the substrate surface between the constricted conductor pattern surfaces of the line conductor 33. The shape of the base 34 is the same as the example of the base 31.

  The resistor 8 is an isolation resistor that constitutes a Wilkinson power combining circuit. A thin film resistor is used for the resistor 8. The resistor 8 is connected to the pattern of the line conductor 33 by a bonding wire 36.

  Further, the input impedance matching circuit 27 saw the characteristic impedance of the semiconductor element 24 seen from the output signal branched into two by the power branch circuit 25 (microstrip line), and the power branch circuit 25 seen from the gate electrode of the semiconductor element 24. Match the characteristic impedance. The input impedance matching circuit 27 is a line conductor 30 on the plate 13, a chip inductor, or a chip capacitor.

  The output impedance matching circuit 28 matches the characteristic impedance of the power combining circuit 26 (microstrip line) viewed from the drain electrode of the semiconductor element 24 and the characteristic impedance of the semiconductor element 24 viewed from the input side of the power combining circuit 26. The output impedance matching circuit 28 is also a line conductor 33 on the plate 13, a chip inductor, and a chip capacitor. Both the input impedance matching circuit 27 and the semiconductor element 24 and the semiconductor element 24 and the output impedance matching circuit 28 are connected by a bonding wire 29.

  When a microwave signal is input from the input terminal 17 to the high-frequency circuit device 10 having the above-described configuration, the high-frequency circuit device 10 guides the microwave signal on the line conductor 30 and branches it into two. The power combining circuit 25 outputs each signal with equal amplitude to an input impedance matching circuit 27 connected in parallel to the power combining circuit 26. The microwave signal is bifurcated without changing its impedance and causing reflection. The semiconductor element 24 amplifies the microwave signal input from the input impedance matching circuit 27 via each gate terminal pad. The semiconductor element 24 outputs an amplified signal to the impedance matching circuit 28 from each drain terminal pad arranged opposite to each gate terminal pad. Each of the amplified microwave signals is converted in impedance and propagated to the power combining circuit 26. The power combining circuit 26 combines the microwave signals and outputs them from the output terminal 19.

  The power branch circuit 25 propagates microwave signals having substantially the same amplitude and phase. The resistor 7 does not substantially pass a current as an isolation resistor, or if it flows, converts the current into Joule heat and does not pass power. The resistor 7 substantially does not consume power. Thereby, the line conductor 30 of the power branch circuit 25 propagates the microwave signal so as not to cause a potential difference between the branched conductor pattern surfaces. The resistor 8 in the power combining circuit 26 is the same as the example of the resistor 7.

  FIG. 4 is a longitudinal sectional view of the mounting structure 1 and shows a section taken along the line III-IV in FIG. The above described symbols represent the same elements. Illustration of the bonding wire 32 is omitted.

  The bottom surface of the base 31 of the mounting structure 1 is located in the same plane a11 as the formation surface of the line conductor 30, and the upper surface thereof is located above the plane a11 and in a plane a12 parallel to the plane a11. . The mounting structure 1 forms the resistor 7 by aligning the back surface of the resistor 7 in the plane a12. This mounting structure 1 makes it possible to mount the resistor 7 at a height position away from the ground plane a14. The height measured from the ground surface a14 of the resistor 7 when the resistor 7 is provided on the base 31 is the ground surface a14 of the resistor 7 when the resistor 7 is provided on the plane a11. You can earn more than the height measured from Compared to the conventional example in which a resistance film is formed on a flat surface, the parasitic capacitance due to the resistor 7 can be reduced. The parasitic capacitance of the resistor 7 to the plate 13 can be reduced more than the parasitic capacitance of the resistance film according to the conventional example. The resistor 8 and the base 34 are the same as the example using the resistor 7 and the base 31.

  The circuit connection structure according to the conventional example uses a mounting method in which a resistor is formed on the same plane as the formation surface of the line conductor of the microstrip line. However, in this mounting method, the resistor has a large parasitic capacitance with respect to the ground plane depending on the distance between the resistor and the ground plane and the substrate material of the dielectric substrate. The large parasitic capacitance means that the signal power propagating through the microstrip line is so large that the constant of the distributed line changes.

In general, when the capacitance C between the electrodes by the parallel plate electrode pair is filled with a material, the capacitance C is expressed by C = ε · S / d. ε represents the dielectric constant in the substance, S represents the electrode area, and d represents the distance between the electrodes. In the case where a charge is placed between the resistor 7 and the plate 13 to form a capacitor with a pair of parallel plate electrodes, the parasitic capacitance is determined between the film-like or chip-like resistor 7 and the ground plane of the plate 13. It is represented by the grounding capacity between. The height of the insulating base 31 increases the distance d between the electrodes in order to increase the distance between the resistor 7 and the grounding surface of the plate 13. The distance between the electrodes forming the parasitic capacitance according to the conventional example is d ₀ (d> d ₀ ). If ε and S are taken in common, the capacitance C by the mounting structure 1 can be made smaller than the capacitance C ₀ by the conventional example. When the microwave signal propagates through the power branch circuit 25, there is a case where the microwave signal shows a capacitive reactance when the impedance of the resistor 7 which is purely resistive is seen. According to the mounting structure 1, even if the microwave signal is viewed by the resistor 7 as a capacitive element, the value of the parasitic capacitance can be reduced by the presence of the base 31, and the characteristic impedance of the line is not changed. The degree to which the resistor 7 acts as a microwave signal as an element having a capacitive reactance component does not deteriorate the high frequency characteristics of the line and does not affect the performance of the high frequency circuit.

  FIG. 5 shows a mounting structure according to the modification. FIG. 5 is a longitudinal sectional view of a mounting structure according to a modified example, and shows a section taken along the line III-IV in FIG. The above described symbols represent the same elements. The illustration of the bonding wire material is omitted. The mounting structure 9 includes a plate 13, a substrate 3, a line conductor 30 constituting a microstrip line, an insulating base 35, and a resistor 7. The surface on which the resistor 7 is formed on the base 35 may be inclined. Since the resistor 7 is separated from the plate ground surface by a size larger than the substrate thickness by the height of the base 35, the parasitic capacitance is reduced. The surface on which the resistor 7 is formed on the base 35 may be curved. FIG. 5 shows an example of the power branch circuit on the input side, but the base 34 of the power synthesis circuit on the output side may also be inclined or curved on the surface on which the resistor 8 is formed.

(Second Embodiment)
In the mounting structures 1 and 9 and the high-frequency circuit device 10, the base 31 is fixed on the main surface of the substrate 3. In the second embodiment, a method for mounting the resistor 7 for a high-frequency circuit will be described.

  FIG. 6 is a longitudinal sectional view of the mounting structure according to the second embodiment. The above described symbols represent the same elements. The illustration of the bonding wire material is omitted. The mounting structure 40 is a structure in which a substrate 37 on which the resistor 7 is formed is bonded onto the substrate 3 by using an adhesive 38. In other respects, the mounting structure 40 is the same as the mounting structures 1 and 9 described above. The high frequency circuit device according to the present embodiment includes the mounting structure 40 and has the same configuration as the high frequency circuit device 10.

  The substrate 37 is a dielectric substrate. AuSn (gold tin) solder is used for the adhesive 38. In the manufacturing apparatus, the resistor 7 is formed in advance on the upper surface of the substrate 37, and the substrate 37 on which the resistor 7 is placed is placed on the main surface of the substrate 3 from above the substrate 3 on which the high-frequency circuit such as the line conductor 30 exists. Glue. As a result, the resistor 7 is separated from the ground plane 39. Thereby, the parasitic capacitance of the resistor 7 is reduced. The high frequency circuit device may have the same mounting structure as the mounting structure 40 on the power combining board 26 side.

  In the high-frequency circuit device according to this embodiment having such a configuration, an Au layer as a base material is formed on a desired region on the substrate 3, and AuSn solder as a brazing material is used on the Au layer. For example, the bottom surface of the rectangular parallelepiped substrate 37 is fixed to the main surface of the substrate 3 with an adhesive 38. The manufacturing apparatus separately prepares a substrate 37 with a resistor 7, and bonds the substrate 37 with a resistor 7 onto the substrate 3 from above the substrate 3. The mounting surface of the resistor 7 can be separated from the ground plane 39, and the parasitic capacitance can be reduced.

  The mounting structure according to the conventional example uses a mounting method in which a resistor is formed on the same plane as the transmission line. In this mounting method, the resistor has a large parasitic capacitance with respect to the ground plane depending on the distance between the resistor and the ground plane or the substrate material. On the other hand, the mounting structure 40 can increase the height dimension of the mounting surface of the resistor 7 by bonding and fixing with the adhesive 38. The height measured from the ground surface 39 of the resistor 7 when the resistor 7 is mounted on the substrate 37 is the same as the ground surface 39 of the resistor 7 when the resistor 7 is mounted on the substrate 3. It can be made larger than the height measured from The parasitic capacitance due to the resistor 7 can be reduced as compared with the conventional example.

(Other)
The above-described embodiment is not limited to the embodiment as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. In the above embodiment, the bases 31 and 34 are provided on the input and output sides, respectively, but even if only one of the base 31 and the base 34 is provided, the effect of reducing the parasitic capacitance can be obtained.

  In the second embodiment, a brazing material such as lead tin solder, gold silicon (AuSi), or gold germanium (AuGe) may be used as the adhesive. A conductive adhesive such as epoxy, polyimide, polymer or silver glass may be used.

  Although several embodiments have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1,9,40 ... Mounting structure, 2 ... Package, 3, 4, 5, 6 ... Board | substrate, 7, 8 ... Resistor, 10 ... High frequency circuit apparatus, 11 ... Cover, 12 ... Wall body, 13 ... Plate, 14 , 15 ... feed-through portion, 16, 18 ... through conductor, 17 ... input terminal, 19 ... output terminal, 20 ... sealing material, 21, 22, 23 ... dielectric, 24 ... semiconductor element (high-frequency semiconductor element), 25 ... Power branching circuit (microstrip line), 26 ... Power combining circuit (microstrip line), 27 ... Input impedance matching circuit, 28 ... Output impedance matching circuit, 29 ... Bonding wire, 30 ... Line conductor, 31,34,35 ... Base, 32 ... bonding wire, 33 ... line conductor, 36 ... bonding wire, 37 ... substrate, 38 ... adhesive, 39 ... grounding surface, 50 ... notch.

Claims (5)

A conductive plate having a ground plane;
A dielectric substrate provided on the plate, having a back surface on the grounding surface side of the plate and a main surface opposite to the back surface;
A microstrip line is configured with these substrates and plates, and a line conductor provided on the main surface of the substrate;
An insulating base provided on the substrate and insulated from the line conductor;
A resistor provided on the base and spaced apart from the ground plane of the plate in a dimension larger than the substrate thickness of the base by the base height of the base, and connected to the line conductor;
A mounting structure comprising   The mounting structure according to claim 1, wherein the base is fixed to the main surface of the substrate with an adhesive. A conductive plate having a ground plane;
A high-frequency semiconductor element grounded to the plate;
A package having a wall that surrounds the high-frequency semiconductor element, a plurality of through conductors that pass through the wall, and a lid that seals a space including the high-frequency semiconductor element on the wall;
A dielectric substrate having a back surface on the grounding surface side of the plate and a main surface opposite to the back surface, provided on at least one of the input and output of the high-frequency semiconductor element in the package;
A microstrip line is configured with the substrate and the plate, and the line conductor on the substrate is electrically connected to the through conductor;
An insulating base provided on the substrate and insulated from the line conductor;
A resistor provided on the base and spaced apart from the ground plane of the plate in a dimension larger than the substrate thickness of the base by the base height of the base, and connected to the line conductor;
A high frequency circuit device comprising:   The high-frequency circuit device according to claim 3, wherein the base is fixed to the main surface of the substrate with an adhesive.   The high-frequency circuit device according to claim 3, wherein a surface on which the resistor is formed is inclined with respect to a main surface of the substrate.

Images