JP5728102B1 - MMIC integrated circuit module - Google Patents

Abstract

An increase in propagation loss of a waveguide due to warping of a dielectric substrate in an MMIC integrated circuit module is prevented. A horizontal waveguide 101, a bending waveguide 102, and a vertical waveguide 103 are formed in an MIC integrated circuit module. As a result, the opening area per dielectric substrate (1, 2, 4) can be reduced, and hence the warpage caused by the stress of the lamination applied to the dielectric substrate can be reduced, and the waveguide caused by the warpage can be reduced. An increase in propagation loss can be prevented. [Selection] Figure 1

Description

  The present invention relates to a technique for preventing an increase in propagation loss of a waveguide caused by warpage of a dielectric substrate in an MMIC integrated circuit module.

  FIG. 4 is a cross-sectional view of a conventional MMIC integrated circuit module. 5 is a BB arrow view of FIG.

  On the base 71 in the waveguide 8 cut and formed in the metal base 7, the dielectric substrate 9 on which the MMIC 3 and the power supply wiring and signal wiring to the MMIC 3 are formed is mounted. A part of the waveguide 8, the shielding part 2 a, and the IC storage part 2 b are formed on the metal lid 20 by cutting as with the metal base 7.

  In the circuit area 31 of the MMIC 3, circuits such as transmission / reception amplifiers and modulators are formed. The circuit region 31 and the external wiring pin 30 are connected via the dielectric substrate 9 and the pads 9P on the dielectric substrate 9.

  The waveguide coupling unit 32 has a function of converting the TE 10 mode of the waveguide 8 to the waveguide mode of the transmission line in the MMIC 3. In order to efficiently couple with the TE10 mode of the waveguide 8, the waveguide coupling portion 32 is disposed at approximately the center of the waveguide 8. The shield 2a is formed one step lower than the waveguide 8 so that electromagnetic waves do not leak into the IC storage 2b.

  For example, a metal horn (not shown) or the like is connected to the opening 81 of the waveguide 8.

Yi-Chi Shih, Thuy-Nhung Ton, and Long Q. Bui, “WAVEGUIDE-TO-MICROSTRIP TRANSITIONS FOR MILLIMETER-WAVE APPLICATIONS”, IEEE MTT-S International Microwave Symposium Digest, pp. 473-475, vol.1, MAY 1988. Lei Xia, Ruimin Xu, Bo Yan, “LTCC-Based Highly Integrated Millimeter-Wave Receiver Front-End Module”, Int J Infrared Milli Waves, pp. 975-983, vol.27, 2006.

  In the conventional MIC integrated circuit module shown in FIG. 4 and the like, it is difficult to reduce the size because the dielectric substrate needs to be mounted and the size of the external power supply and the external wiring pin becomes large. In addition, in order to form a waveguide with a metal base and a metal lid, high-precision cutting technology and special plating technology are required, and high cost has been a problem.

  For example, by using a multilayer dielectric substrate instead of a metal base, downsizing and reduction in processing cost can be realized.

  However, when a multilayer dielectric substrate is used, the dielectric substrate may be warped due to the stress of lamination. Then, electromagnetic wave leakage may occur due to warpage, and propagation loss of the waveguide may increase.

  The present invention has been made in view of the above problems, and an object of the present invention is to prevent an increase in propagation loss of a waveguide due to warping of a dielectric substrate in an MMIC integrated circuit module.

In order to solve the above-described problems, an MMIC integrated circuit module according to the present invention includes a first dielectric substrate having an opening formed thereon, and is stacked on one surface of the first dielectric substrate. A second dielectric substrate having an opening formed in accordance with a region where the pedestal that is the portion of the first dielectric substrate facing the portion and the opening is combined, and mounted on the one surface of the pedestal An MMIC, a third dielectric substrate laminated on the other surface of the first dielectric substrate, and having an opening formed in a region not in contact with the pedestal in the opening of the first dielectric substrate; A through hole provided in the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate so as to surround openings of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate; A metal layer and the one surface of the second dielectric substrate; Disposed toward the opening of the first dielectric substrate and a metal lid with a recess formed to open in the concave portion of the metal lid, the portion facing the opening of the third dielectric substrate , and wherein the inclined surface portion der Rukoto which are inclined in the direction of the MMIC.

  ADVANTAGE OF THE INVENTION According to this invention, the propagation loss increase of the waveguide resulting from the curvature of the dielectric substrate in a MMIC integrated circuit module can be prevented.

It is sectional drawing of the MMIC integrated circuit module which concerns on 1st Embodiment. It is an AA arrow line view of FIG. It is a top view of the MMIC integrated circuit module of FIG. It is sectional drawing of the conventional MMIC integrated circuit module. It is a BB arrow line view of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a cross-sectional view of the MMIC integrated circuit module according to the first embodiment. FIG. 2 is an AA arrow view of FIG. FIG. 3 is a top view of the MMIC integrated circuit module of FIG.

  As shown in FIG. 1, the MMIC integrated circuit module is laminated on a first dielectric substrate 1 having an opening 11 formed on one surface (the upper surface in the figure) of the first dielectric substrate 1 and the opening A second dielectric substrate 2 in which an opening 21 is formed in accordance with a region where the pedestal 12 which is a part of the first dielectric substrate 1 facing a part of the substrate 11 and the opening 11 are combined; MMIC (monolithic microwave integrated circuit) 3 mounted on one side (upper side in the figure) and the other side (lower side in the figure) of the first dielectric substrate 1 are laminated, A third dielectric substrate 4 (three in the figure) in which an opening 41 is formed in accordance with a region 111 not in contact with the pedestal 12 in the opening 11 of the first dielectric substrate 1, and the first dielectric substrate 1 The first dielectric substrate 1 is provided so as to surround the opening 11 of the first dielectric substrate 1. Through-via 1A and metal layer 1B, through-via 2A and metal layer 2B provided in second dielectric substrate 2 so as to surround opening 21 of second dielectric substrate 2, and opening of third dielectric substrate 4 41, a through via 4A and a metal layer 4B provided in the third dielectric substrate 4 so as to surround the first dielectric substrate 1, and a first dielectric substrate 1 disposed on one surface side (the upper surface in the drawing) of the second dielectric substrate 2. And a metal lid 5 formed with a recess 51 that opens toward the opening 11.

  With such a configuration, the horizontal waveguide 101, the bending waveguide 102, and the vertical waveguide 103 are formed in the MMIC integrated circuit module. That is, an L-shaped waveguide is formed. The height of the waveguide is, for example, 0.8 mm, and the width is, for example, 0.4 mm. In this case, it becomes an H-plane bending waveguide. In order to function as a waveguide, it is preferable that the interval between through vias in the same dielectric substrate is ¼ or less of the wavelength of the electromagnetic wave propagating through the waveguide. Thereby, electromagnetic waves do not leak from between the through vias and function as a waveguide. For the metal layer and the through via, for example, a silver paste mixed with a conductive silver filler is used.

  Each dielectric substrate can be made of low temperature fired ceramics (LTCC), polyimide, or the like, and has a thickness of about 100 μm (micron), for example.

  The number of dielectric substrates is not limited to the number of the present embodiment, and for example, four or more third dielectric substrates 4 may be provided in order to lengthen the vertical waveguide 103.

  Here, as a comparative example, consider an MMIC integrated circuit module in which the bending waveguide 102 and the vertical waveguide 103 are not provided, and the horizontal waveguide 101 is extended to the left side of the figure.

  When the MMIC integrated circuit module of the present embodiment and the MMIC integrated circuit module of the comparative example have the same substantial length of the waveguide, the waveguide of the MMIC integrated circuit module of the present embodiment is L Since it is a letter shape, the opening area per dielectric substrate can be reduced. Therefore, the warpage due to the stress of the lamination applied to the dielectric substrate can be reduced, and an increase in the propagation loss of the waveguide due to the warpage can be prevented.

  The MMIC 3 includes a circuit region 31 and a waveguide coupling portion 32 connected to the circuit region 31. In the circuit area 31, circuits such as amplifiers and modulators for transmission and reception are formed. The waveguide coupling unit 32 has a function of converting the TE10 mode of the horizontal waveguide 101 to the waveguide mode of the transmission line in the MMIC 3.

  The MMIC 3 is, for example, a compound semiconductor that forms an integrated circuit. The MMIC 3 is fixed to the pedestal 12 with, for example, a conductive adhesive.

  Even if the waveguide coupling portion 32 is formed on a polymer substrate or the like on which the MMIC 3 is mounted, the same configuration is obtained.

  The waveguide coupling portion 32 is preferably arranged at the center of the H surface of the horizontal waveguide 101 by appropriately selecting the thickness of the MMIC 3 and the thickness and number of the first dielectric substrate 1, for example. Such an arrangement enables efficient coupling conversion.

  The recess 51 is plated with gold or the like. Moreover, the part which comprises the bending waveguide 102 of the recessed part 51 becomes the slope part 511, and can suppress the change of an impedance. That is, the electromagnetic wave from the horizontal waveguide 101 is guided to the vertical waveguide 103, and the electromagnetic wave from the vertical waveguide 103 is guided to the horizontal waveguide 101. The surface of the slope portion 511 is preferably flat and smooth, but may be stepped. In this case, the step of the staircase is preferably about 1/10 of the wavelength.

  Further, the portion of the recess 51 that constitutes the horizontal waveguide 101 has a height corresponding to the height of the horizontal waveguide 101, but the portion of the recess 51 that faces the pedestal 12 is the horizontal waveguide. The shielding portion 512 is one step lower so that the electromagnetic wave does not leak from the tube 101 in the right direction (an IC storage portion 514 described later) in the drawing. Further, the IC storage unit 514 connected to the shielding unit 512 is designed so as not to contact the MMIC 3 and the pad 2P.

  As shown in FIG. 2, through vias (1A, 2A, 4A) and metal layers (1B, 2B, etc.) are formed around the horizontal waveguide 101 and the bent waveguide 102.

  The E-face wall E on the short side of the waveguide is composed of the metal layer 1B. Further, through-vias (1A, 2A, 4A) and metal layers (2B, etc.) are formed on the H-side wall H on the long side of the waveguide.

  The impedance of the horizontal waveguide 101 can be controlled by the size of the waveguide and the arrangement of through vias, and it is preferable that the coupling efficiency with the waveguide coupling portion 32 is maximized.

  Further, the horn antenna may be formed by gradually expanding the vertical waveguide 103 in the direction of the E plane and the H plane.

  On the upper surface of the second dielectric substrate 2, a power supply wiring and signal wiring (both not shown) to the MMIC 3 and a connection pad 2P are formed.

  Further, the MMIC integrated circuit module has a minute gap due to the warp of the substrate sandwiched between the peripheral portion 52 of the recess 51 in the metal lid 5 and the metal layer 2B of the second dielectric substrate 2 facing the peripheral portion. In order to close it, a plurality of stud bumps 6 may be further provided. The stud bump 6 is made of, for example, gold. Further, it has the same potential as the metal layer 2B, the through via 2A, or the like.

  The stud bump 6 is arranged so as not to be electrically connected to the power supply wiring, the signal wiring, and the pad 2P in a portion where the metal layer 2B of the second dielectric substrate 2 is not present.

  The stud bump 6 has, for example, a spherical shape, and prevents the electromagnetic waves from leaking between the metal lid 5 and the metal layer 2B by setting the arrangement interval between the centers to ¼ or less of the wavelength (for example, 200 μm). it can.

  In an ideal state where there is no warpage due to lamination in each dielectric substrate, each stud bump 6 is not necessary. However, if there is a warp, the arrangement distance between the centers of the stud bumps 6 is set to, for example, ¼ or less of the wavelength as described above to prevent leakage of electromagnetic waves, and the lowest third dielectric in FIG. It is preferable to individually adjust (leveling adjustment) the size of each stud bump 6 so that the upper surface of the metal lid 5 is parallel to the lower surface (bottom surface) of the substrate 4.

  As described above, according to the MIC integrated circuit module according to the present embodiment, the horizontal waveguide 101, the bending waveguide 102, and the vertical waveguide 103 are formed. The area of the opening can be reduced, so that the warp caused by the stress of the lamination applied to the dielectric substrate can be reduced, and an increase in the propagation loss of the waveguide caused by the warp can be prevented.

  In addition, since the MMIC integrated circuit module according to the present embodiment is formed by stacking dielectric substrates, power can be supplied to the MMIC and signals can be supplied by providing through vias and wiring on the dielectric substrate. Since the wave tube can be integrally formed, the MMIC integrated circuit module can be reduced in size. In addition, a metal base is not required, and therefore high-precision cutting technology and special plating technology are not required, so that the processing cost can be reduced.

DESCRIPTION OF SYMBOLS 1 ... 1st dielectric substrate 1A, 2A, 4A ... Through-via 1B, 2B, 4B ... Metal layer 2 ... 2nd dielectric substrate 3 ... MMIC
DESCRIPTION OF SYMBOLS 4 ... 3rd dielectric substrate 5 ... Metal lid 6 ... Stud bump 7 ... Metal base 11 ... Opening part 12 ... Base 21 ... Opening part 31 ... Circuit area 32 ... Waveguide coupling part 41 ... Opening part 51 ... Concave part 52 ... Surrounding portion 101 ... Horizontal waveguide 102 ... Bending waveguide 103 ... Vertical waveguide 111 ... Region 511 ... Slope portion 512 ... Shielding portion 514 ... IC storage portion E ... E surface wall H ... H surface wall

Claims (2)

A first dielectric substrate having an opening formed thereon;
The first dielectric substrate is laminated on one surface, and an opening is formed in accordance with a region where the pedestal that is a portion of the first dielectric substrate facing a part of the opening and the opening is combined. A second dielectric substrate;
MMIC mounted on the one surface of the pedestal;
A third dielectric substrate laminated on the other surface of the first dielectric substrate and having an opening formed in a region not in contact with the pedestal in the opening of the first dielectric substrate;
Through vias provided in the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate so as to surround the openings of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate. And with a metal layer,
A metal lid disposed on the one surface side of the second dielectric substrate and formed with a recess that opens toward the opening of the first dielectric substrate ;
In the recess of the metal cover, the portion facing the opening of the third dielectric substrate, MMIC integrated circuit module, wherein the Ru slope portion der which is inclined in the direction of the MMIC. 2. The MMIC integrated circuit according to claim 1, further comprising: a plurality of stud bumps sandwiched between a peripheral portion of the concave portion of the metal lid and a metal layer of the second dielectric substrate facing the peripheral portion. module.