JP5728101B1 - MMIC integrated circuit module - Google Patents

Abstract

Variations in characteristics of a waveguide microstrip line converter in an MMIC integrated circuit module are reduced. A dielectric substrate 1 of an MMIC integrated circuit module is provided with a metal wall 9 opposed to a stepped portion 8. The gap (P) between the stepped portion 8 can be narrowed by adjusting the height (L) of the stepped portion 8 and the thickness (M) of the metal wall 9, thereby blocking electromagnetic waves. Therefore, the characteristic variation of the waveguide microstrip line converter 10 can be reduced. [Selection] Figure 3

Description

  The present invention relates to a technique for reducing variation in characteristics of a waveguide microstrip line converter in an MMIC integrated circuit module.

  FIG. 9 is a partial cross-sectional view of a conventional MMIC integrated circuit module. FIG. 10 is an AA arrow view of FIG.

  In the conventional MMIC integrated circuit module, for example, a waveguide 21 formed from a metal pedestal 200 is arranged on one side (lower side in the figure) of the dielectric substrate 1. A probe 4, a conductor line 5, and a ground conductor 6 are formed on the dielectric substrate 1. Dielectric substrate 1, conductor line 5, and ground conductor 6 constitute a microstrip line. Although not shown, an antenna or the like is connected to the waveguide 21 on the lower side in the drawing. The metal lid 7 covering the dielectric substrate 1 is formed with a step portion 8 and a frame portion 7a. A waveguide microstrip line converter is configured by the back short 7b which is a space between the frame portion 7a and the stepped portion 8 (see Non-Patent Document 1).

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 MMIC integrated circuit module, there is a gap (Q in FIG. 10) between the dielectric substrate 1 and the stepped portion 8, and due to insufficient processing accuracy of the metal lid 7 and alignment accuracy with the dielectric substrate 1, When the gap becomes large, the electromagnetic wave from the back short 7b leaks from the gap, and the characteristics of the waveguide microstrip line converter vary.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the characteristic variation of the waveguide microstrip line converter in the MMIC integrated circuit module.

In order to solve the above-described problem, an MMIC integrated circuit module according to the first aspect of the present invention is laminated on a dielectric substrate on which convex portions projecting outward are formed, and on one side of the dielectric substrate, Mounted on the other surface of the dielectric substrate, one or more dielectric layers having openings formed in accordance with the protrusions, through vias and metal layers provided in the dielectric layers so as to surround the openings In the MMIC, a probe that is a metal layer formed on the convex portion on the other surface, a conductor line that is a metal layer connecting the probe and the MMIC on the other surface, and the one surface, A grounding conductor, which is a metal layer formed so as to face the conductor line, a metal lid that covers the dielectric substrate from the other surface side, a metal lid that protrudes from the metal lid to the dielectric substrate side, and the conductor line; Three-dimensional And the step portion provided so as to intersect said at other side, except for the location of the conductor line, and a metal wall which is disposed so as to face the stepped portion, the said stepped portion and the metal lid side It closed with a metal lid and the step portion, the space in which a back short opening to the dielectric substrate side is formed, characterized in Rukoto.

An MMIC integrated circuit module according to a second aspect of the present invention includes a dielectric substrate in which an opening and a protrusion protruding from the opening are formed, and is laminated on one side of the dielectric substrate, and the protrusion At least one dielectric layer having an opening formed in accordance therewith, a through via and a metal layer provided in the dielectric layer so as to surround the opening of the dielectric layer, and on the other surface of the dielectric substrate. A mounted MMIC, a probe that is a metal layer formed on the convex portion on the other surface, a conductor line that is a metal layer connecting the probe and the MMIC on the other surface, and the one surface A ground conductor which is a metal layer formed so as to face the conductor line, a metal lid which covers the dielectric substrate from the other surface side, a metal lid protruding from the metal lid to the dielectric substrate side, and the dielectric Board opening And the stepped portion formed so as to surround said at other side, except for the location of the conductor line, and a metal wall which is disposed so as to face the stepped portion, the stepped portion and the metal lid side It closed with the said metal lid and said step portion, the space in which a back short opening to the dielectric substrate side is formed, characterized in Rukoto.

  According to the present invention, it is possible to reduce the characteristic variation of the waveguide microstrip line converter in the MMIC integrated circuit module.

It is sectional drawing of the MMIC integrated circuit module which concerns on 1st Embodiment. FIG. 2 is a partial cross-sectional view of the MMIC integrated circuit module of FIG. 1. It is an AA arrow line view of FIG. It is a BB arrow line view of FIG. It is a figure which shows the S parameter characteristic in the 300 GHz band of the waveguide microstrip line converter in 1st Embodiment. It is a fragmentary sectional view in the MMIC integrated circuit module concerning a 2nd embodiment. It is an AA arrow line view of FIG. It is a BB arrow line view of FIG. It is a fragmentary sectional view in the conventional MMIC integrated circuit module. It is an AA 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 a partial cross-sectional view of the MMIC integrated circuit module of FIG. FIG. 3 is an AA arrow view of FIG. FIG. 4 is a BB arrow view of FIG.

  The MMIC integrated circuit module is laminated on the dielectric substrate 1 formed with a protruding portion 1a protruding outward, and on one side (lower side in the figure) of the dielectric substrate 1, and an opening is formed in accordance with the protruding portion 1a. A plurality of (three in the figure) dielectric layers 2 formed with 2a, through vias 2b and metal layers 2c provided in the dielectric layer 2 so as to surround the openings 2a, and the other surface of the dielectric substrate 1 ( The metal formed on the convex portion 1a on the MMIC (monolithic microwave integrated circuit) 3 mounted on the upper surface in the drawing and the other surface (upper surface in the drawing) of the dielectric substrate 1 The probe 4 that is a layer, the conductor line 5 that is a metal layer that connects the probe 4 and the MMIC 3 on the other surface (the upper surface in the figure) of the dielectric substrate 1, and the one surface (the lower surface in the figure) Side surface) on the conductor line 5 A grounding conductor 6 that is a metal layer formed so as to face, a metal lid 7 that covers the dielectric substrate 1 from the other surface side (upper side in the figure), and a conductor line that protrudes from the metal lid 7 to the dielectric substrate 1 side. 5 is arranged so as to face the stepped portion 8 except for the portion of the conductor line 5 on the other surface (upper surface in the drawing) of the dielectric substrate 1. And a metal wall 9.

  For example, two dielectric layers 2 are further laminated below the three dielectric layers 2. A dielectric layer 2 (four layers in the figure) is also laminated on the other surface side (upper side in the figure) of the dielectric substrate 1 except for the metal lid 7 portion. A space in which the metal lid 7 is arranged is called a cavity. The cavity is, for example, a rectangle.

  The material of the dielectric substrate 1 is, for example, a polymer material such as polyimide having a relative dielectric constant of 4 or less, quartz, or a liquid crystal polymer. By using the dielectric substrate 1 having a low relative dielectric constant, it is possible to widen the bandwidth. The thickness of the dielectric substrate 1 is, for example, 25 μm (microns).

  The material of the dielectric layer 2 is, for example, LTCC (Low Temperature Confired Ceramics) which is a kind of ceramic material. The thickness of the dielectric layer 2 is several tens to several hundreds μm. In addition to LTCC, the material may be ceramics, a ceramic mixed material in which ceramics and a glass filler are mixed, or a polymer material such as polyimide, and a material having a small dielectric loss is desirable. When using a ceramic material, firing is performed at a high temperature after lamination.

  The MMIC 3 includes, for example, a receiving chip composed of a compound semiconductor substrate, and is flip-chip mounted on the dielectric substrate 1 via bumps in a cavity. The frame portion 7a of the metal lid 7 is in close contact with the dielectric layer 2 outside the cavity, and thus the MMIC 3 is sealed. The MMIC 3 may be mounted on the dielectric substrate 1 by wire bonding.

  In addition to the conductor line 5 and the ground conductor 6, a wiring pattern and a through via are formed on the dielectric substrate 1. In addition to the through via 2b and the metal layer 2c, a wiring pattern and a through via are formed in the dielectric layer 2. Also, solder bumps 23 are formed on the uppermost dielectric layer 2 so as to be electrically connected to the through vias.

  The material of the conductor line 5, the ground conductor 6 and the wiring pattern of the dielectric substrate 1 is copper or the like, formed by etching, and the surface is processed by gold plating or the like. The thickness is about 15 μm.

  The material of the metal layer 2c of the dielectric layer 2 and the wiring pattern is gold, silver, tungsten, copper or the like, and has a thickness of several to several tens of μm, and is formed by silk screen printing or plating.

  A data connector 31 is attached to the substrate 30, and the electrode 31 a is electrically connected to the solder bump 23.

  Thereby, the signal line 31b of the data connector 31 is electrically connected to the wiring pattern in the MMIC 3 via the wiring pattern of the dielectric layer 2 and the dielectric substrate 1 and the through vias and the bumps between the MMIC 3 and the dielectric substrate 1. Connected to. Signals are transmitted and received between the MMIC 3 and the outside via this electrical wiring.

  Further, DC pins 32 are attached to the substrate 30, and the DC pins 32 are electrically connected to the solder bumps 23 via a wiring pattern on the substrate 30.

  As a result, the DC pin 32 is electrically connected to the power supply pattern in the MMIC 3 via the wiring pattern of the dielectric layer 2 and the dielectric substrate 1, the through via, and the bump between the MMIC 3 and the dielectric substrate 1. . Power is supplied to the MMIC 3 from the outside via this electrical wiring.

  In the three dielectric layers 2 below the dielectric substrate 1, the area of the opening 2a is equal, and the through via 2b and the metal layer 2c in these dielectric layers 2 form a pseudo metal wall, That is, the waveguide 21 is configured. The dielectric layer 2 constituting the waveguide 21 may be one layer, two layers, or four or more layers.

  The diameter of the through via 2b is, for example, 100 μm. The interval between the through vias 2b (FIG. 2: D) is set to ¼ or less of the wavelength of the electromagnetic wave used, for example. That is, it is 250 μm or less at a frequency of 300 GHz.

  The size of the waveguide 21 is set in accordance with a predetermined waveguide, and is, for example, 800 μm (FIG. 2; E) × 400 μm (FIG. 2: F). Further, the length of the waveguide 21 (the total thickness of the three dielectric layers 2 in the figure) is, for example, 300 μm.

  In the two dielectric layers 2, the area of the opening 2 a increases stepwise, and the metal layer 2 c in these dielectric layers 2 constitutes the horn antenna 22 in a pseudo manner. The horn antenna 22 may be replaced with a lens or the like.

  The waveguide 21 and the horn antenna 22 are connected to the ground potential wiring of the MMIC 3 through wiring patterns and through vias of the dielectric layer 2 and the dielectric substrate 1 and bumps between the MMIC 3 and the dielectric substrate 1. Therefore, the waveguide 21 and the like are the same as the ground potential of the MMIC 3.

  The microstrip line is formed by sandwiching the dielectric substrate 1 between the conductor line 5 and the ground conductor 6.

  Reference numeral 5a denotes an impedance matching unit that matches the impedances of the probe 4 and the microstrip line to reduce reflection loss. As the impedance matching unit 5a, for example, a λ / 4 matching line having a different line width is used.

  The probe 4 is located at the center in the long side direction when the waveguide 21 is viewed in plan. The width of the probe 4 (FIG. 2: G) is, for example, 50 μm. The substrate end 1 c of the dielectric substrate 1 is mounted in alignment with the end 21 a (long side) of the waveguide 21. By such a method, the length of the probe 4 can be defined by the length of the convex portion 1a, and mounting becomes easy.

  In order to reduce the impedance of the probe 4, the convex portion 1 a is formed by, for example, removing a die from a substrate serving as a prototype of the dielectric substrate 1 or cutting a substrate using a laser.

  The width (FIG. 2: H) of the convex portion 1a is, for example, 100 μm, and the length (FIG. 2: I) is, for example, 200 μm.

  By providing the convex portion 1a, the size of the area where the MMIC 3 is mounted can be freely selected, so that the size of the MMIC 3 can be freely selected.

The back short 7b, which is the space between the frame portion 7a of the metal lid 7 and the stepped portion 8, the convex portion 1a located in the back short 7b, and the probe 4 form a waveguide microstrip line converter 10. The waveguide microstrip line converter 10 transmits an electromagnetic wave received by the horn antenna 22 or the like and conducted through the waveguide 21 to the microstrip line, and impedances on the waveguide 21 side and the microstrip line side are transmitted. The back short 7b to be aligned is configured by forming the frame portion 7a and the stepped portion 8 from the metal lid 7 by cutting. The size of the back short 7b is set in accordance with a predetermined waveguide, and is, for example, 800 μm (FIG. 2: E) × 400 μm (FIG. 2: F). The height of the back short 7b (FIG. 3: J) is, for example, about ¼ of the wavelength, for example, 300 μm.

  The height of the back short 7b (FIG. 3: J) is adjusted for impedance matching between the waveguide 21 and the microstrip line. Further, the impedance of the waveguide 21 and the microstrip line can be matched by adjusting the impedance of the waveguide 21.

  The impedance of the waveguide 21 depends on the distance (FIG. 2: K) from the layer end of the dielectric layer 2 constituting the waveguide 21 to the through via 2b. However, if the distance (K) is short, the dielectric layer 2 may be broken. Therefore, it is preferable to adjust the impedance within such a range.

  The frame portion 7a and the step portion 8 are for electromagnetically shielding the back short 7b from the storage area of the MMIC 3, and the height of the frame portion 7a (FIG. 3: J) is, for example, 300 μm. The height 8 (FIG. 3: L) is, for example, 200 μm.

  The metal wall 9 is formed by further plating the wiring pattern of the dielectric substrate 1. The thickness of the metal wall 9 (FIG. 3: M) is about 30 μm.

  The distance between the microstrip line (5, 6) and the metal wall 9 (FIG. 2: N) is about 100 μm. When the microstrip lines (5, 6) are viewed in plan, the metal walls 9 are arranged on both sides with the metal walls 9 therebetween.

  The gap (FIG. 3: P) between the stepped portion 8 and the metal wall 9 can be narrowed by adjusting the height (L) of the stepped portion 8 and the thickness (M) of the metal wall 9. Can be cut off. Therefore, the characteristic variation of the waveguide microstrip line converter 10 can be reduced.

  Further, by providing the metal wall 9, even if the metal lid 7 is slightly displaced in the y direction, the leakage of electromagnetic waves can be reduced, and the characteristic variation of the waveguide microstrip line converter 10 can be reduced.

  The metal wall 9 is electrically connected to the metal layer 2 c through the through via 1 b provided in the dielectric substrate 1, and the metal layer 2 c is connected to the ground potential wiring of the MMIC 3. Therefore, the metal wall 9 becomes the same as the ground potential of the MMIC 3.

  The through vias 1b are provided along the substrate end 1c of the dielectric substrate 1, for example, at intervals of 1/4 of the wavelength.

  Further, the frame portion 7a of the metal lid 7 is in close contact with the dielectric layer 2 outside the cavity, and thus the MMIC 3 is sealed, so that mounting errors can be reduced.

  Further, the height (L) of the stepped portion 8 of the metal lid 7 and the height (J) of the frame portion 7a are adjusted so that the stepped portion 8 is in close contact with the metal wall 9 outside the cavity, and thus the MMIC 3 is sealed. By doing so, mounting errors can be reduced.

  FIG. 5 is a diagram showing S parameter characteristics in the 300 GHz band of the waveguide microstrip line converter according to the first embodiment.

The insertion loss S1 has a flat band up to 330 GHz. The reflection characteristic S2 has a band of 40 GHz or more in a 15 dB band, and shows a good frequency characteristic [second embodiment].
FIG. 6 is a partial cross-sectional view of the MMIC integrated circuit module according to the second embodiment. FIG. 7 is an AA arrow view of FIG. FIG. 8 is a BB arrow view of FIG.

  This MMIC integrated circuit module eliminates the gap (P) in FIG. 3 and reliably blocks electromagnetic waves from the back short 7b. Hereinafter, differences from the MMIC integrated circuit module according to the first embodiment will be described.

  An opening 1d is formed in the dielectric substrate 1, and the protrusion 1a protrudes into the opening 1d. Further, the stepped portion 8 is formed so as to surround the opening 1 d of the dielectric substrate 1 when the dielectric substrate 1 is viewed in plan. The metal wall 9 is disposed so as to face the stepped portion 8 formed so as to surround the opening 1 d of the dielectric substrate 1.

  Since the metal wall 9 is arranged in this way, it is not necessary to provide the frame portion 7a having a height different from the thickness of the stepped portion 8 as in the first embodiment. Accordingly, the stepped portion 8 can be formed by, for example, the same cutting process, and can have a uniform thickness. Therefore, the metal wall 9 and the stepped portion 8 can be brought into close contact with each other, that is, the gap (P) in FIG. 3 can be eliminated, and leakage of electromagnetic waves can be reliably prevented. Further, since the metal wall 9 and the stepped portion 8 are in contact with each other, both can be set to the same potential (ground potential). In addition, since the cutting process is small and the metal lid 7 can have a simple structure, the cost can be reduced.

DESCRIPTION OF SYMBOLS 1 ... Dielectric substrate 1a ... Convex part 1b, 2b ... Through-via 1c ... Substrate edge 1d ... Opening part 2 ... Dielectric layer 2a ... Opening part 2c ... Metal layer 3 ... MMIC
DESCRIPTION OF SYMBOLS 4 ... Probe 5 ... Conductor line 6 ... Grounding conductor 7 ... Metal lid 7a ... Frame part 7b ... Back short 8 ... Step part 9 ... Metal wall 10 ... Waveguide microstrip line converter 21 ... Waveguide 21a ... Waveguide End of tube 22 ... Horn antenna

Claims (2)

A dielectric substrate having a convex portion protruding outward;
One or more dielectric layers laminated on one side of the dielectric substrate and having openings formed in accordance with the convex portions;
A through via and a metal layer provided in the dielectric layer so as to surround the opening;
MMIC mounted on the other surface of the dielectric substrate;
A probe that is a metal layer formed on the convex portion on the other surface;
On the other side, a conductor line that is a metal layer connecting the probe and the MMIC;
On the one surface, a ground conductor, which is a metal layer formed to face the conductor line,
A metal lid that covers the dielectric substrate from the other side;
A stepped portion that protrudes from the metal lid to the dielectric substrate side and is three-dimensionally intersected with the conductor line;
On the other side, except for the location of the conductor line, a metal wall arranged to face the stepped portion, and
MMIC integrated circuit module, wherein the metal lid side of the stepped portion is closed by the said metal lid and said step portion, the Ru space in which a back short opening to the dielectric substrate side is formed. A dielectric substrate having an opening and a protrusion protruding from the opening;
One or more dielectric layers laminated on one side of the dielectric substrate and having openings formed in accordance with the convex portions;
A through via and a metal layer provided in the dielectric layer so as to surround the opening of the dielectric layer;
MMIC mounted on the other surface of the dielectric substrate;
A probe that is a metal layer formed on the convex portion on the other surface;
On the other side, a conductor line that is a metal layer connecting the probe and the MMIC;
On the one surface, a ground conductor, which is a metal layer formed to face the conductor line,
A metal lid that covers the dielectric substrate from the other side;
A stepped portion that protrudes from the metal lid toward the dielectric substrate and surrounds the opening of the dielectric substrate;
On the other side, except for the location of the conductor line, a metal wall arranged to face the stepped portion, and
MMIC integrated circuit module, wherein the metal lid side of the stepped portion is closed by the said metal lid and said step portion, the Ru space in which a back short opening to the dielectric substrate side is formed.