Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Reexamination Certificate
2001-06-05
2003-03-18
Paladini, Albert W. (Department: 2827)
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
C174S261000, C361S777000, C361S783000, C257S664000, C257S728000, C257S778000, C333S247000
Reexamination Certificate
active
06534725
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a high-frequency circuit board used for transmission/reception in a high-frequency band, particularly the millimeter-wave band, and also to a semiconductor device using the high-frequency circuit board.
2. Background Art
One known switch for switching signals is employed in 15 transmission equipment, reception equipment, and transmission/reception modules used for radar or for communications in the microwave or millimeter-wave band.
FIG. 15
is a plan view of a conventional switch MMIC (Monolithic Microwave IC) chip, and
FIG. 16
is a circuit diagram showing an equivalent circuit of the switch.
Referring to
FIG. 15
, reference numeral
100
denotes a switch MMIC chip;
102
a GaAs substrate;
104
an FET;
104
a
a source electrode;
104
b
a drain electrode;
104
c
a gate electrode;
104
d
an air-bridge wire interconnecting source electrodes
104
a
;
106
an input terminal;
108
an input line;
110
an air-bridge wire bridging between the input line
108
and each drain electrode
104
b
;
112
an output line;
114
a connection line connecting between the output line
112
and each drain electrode
104
b
;
116
an output terminal; and
118
a via hole connected to each source electrode
104
a
and to a grounding conductor disposed on the back surface of the GaAs substrate
102
.
Furthermore, in the figure, reference numeral
120
denotes a gate signal input terminal, and
122
denotes a control signal line connected to each gate electrode
104
c
. Reference numeral
124
indicates a capacitor having a first end connected to the control signal line
122
and a second end connected to a via hole
126
, which is further connected to the grounding conductor disposed on the back surface of the GaAs substrate
102
. Reference numeral
128
denotes a resistor.
In
FIG. 16
, the input line
108
and the output line
112
each have a characteristic impedance of 50 &OHgr;. The switch
100
supplies an ON/OFF signal from the gate signal input terminal to each gate electrode
104
c
to pass or cut off a high-frequency signal applied to the input terminal
106
. When the high-frequency signal is passed from the input terminal
106
to the output terminal
116
, the FET
104
is in the OFF-state, and therefore can be regarded as a capacitor having the off-capacitance of the FET. This means that the high-frequency signal is output to the output terminal
116
through a filter composed of the inductance components of the input line
108
and the output line
112
and the off-capacitance of the FET
104
.
In the conventional switch
100
having a configuration as described above, the FET
104
formed on the GaAs substrate
102
is composed of a plurality of FET devices. Accordingly, the value of the off-capacitance of the FET
104
may vary when not all of the FET devices have identical electrical characteristics, which occurs depending on position of the wafer on which the switch
100
is formed or which is caused by process variations.
Especially, when the conventional switch MMIC was applied to a millimeter-wave band, a variation in the off-capacitance affected the filter characteristics and, as a result, the frequency characteristics of the switch varied, reducing the yield of the switch in some cases.
SUMMARY OF THE INVENTION
In order to solve the above problems, it is a first object of the present invention to provide an inexpensive high-frequency circuit board used for switches having good high-frequency characteristics. A second object of the present invention is to provide an inexpensive and highly reliable semiconductor device using such a high-frequency circuit board.
According to one aspect of the present invention, a high-frequency circuit board comprises a dielectric substrate, and a high-frequency signal line is mounted on a main surface of said dielectric substrate and has an input end and an output end for high-frequency signals. Another signal line is disposed on said main surface along said high-frequency signal line, and a first grounding conductor is disposed on said main surface along said high-frequency signal line.
In another aspect, in the high-frequency circuit, said high-frequency signal line may have a plurality of branch portions along which said first grounding conductor and said another signal line are disposed.
In another aspect, the high-frequency circuit may further comprise a second grounding conductor. The first grounding conductor is disposed on one side of said high-frequency signal line with said another signal line between said first grounding conductor and said high-frequency signal line, and said second grounding conductor is preferably disposed along said high-frequency signal line on the other side of said high-frequency signal line.
According to another aspect of the present invention, a semiconductor device comprises a high-frequency circuit board as described above and a plurality of bumps disposed on said high-frequency signal line, said another signal line, and said first grounding conductor of said high-frequency circuit board. Further, a semiconductor chip is disposed on said high-frequency circuit board. The semiconductor chip includes a semiconductor substrate and a transistor disposed on said semiconductor substrate, and the transistor has a control electrode, a first electrode, and a second electrode, wherein said control electrode is connected to said another signal line through one of said plurality of bumps, said first electrode is connected to said first grounding conductor through one of said plurality of bumps, and said second electrode is connected to said high-frequency signal line through one of said plurality of bumps.
REFERENCES:
patent: 4045750 (1977-08-01), Marshall
patent: 4615604 (1986-10-01), Yamada
patent: 5006820 (1991-04-01), Prioste et al.
patent: 5942957 (1999-08-01), Mohwinkel et al.
patent: 6320476 (2001-11-01), Tsukahara
patent: 11-225019 (1999-08-01), None
patent: 2000-165101 (2000-06-01), None
U.S. patent application Ser. No. 09/416,525, Tsukahara, filed Oct. 12, 1999.
Leydig , Voit & Mayer, Ltd.
Mitsubishi Denki & Kabushiki Kaisha
Paladini Albert W.
Vigushin John B.
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