Wave transmission lines and networks – Long line elements and components – Strip type
Reexamination Certificate
2000-11-13
2004-08-10
Lee, Benny (Department: 2817)
Wave transmission lines and networks
Long line elements and components
Strip type
C257S664000, C257S728000
Reexamination Certificate
active
06774748
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an RF package and, more particularly, to an RF package with a feed-through.
A package using a coplanar line is suitable for mounting an MMIC (Microwave Monolithic Integrated Circuit) by flip-chip mounting. D. R. Decker et al., “Multichip MMIC Package for X and Ka Bands”, IEEE Transactions on Components, Packaging and Manufacturing Technology—Part B. Vol. 20, February 1997, pp. 27-33 proposes a ceramic package which is comprised of a promisingly low-cost multilayered substrate.
FIGS. 8
to
11
show the structure of a conventional ceramic package. Referring to
FIG. 8
, a ceramic package
1
is comprised of a cavity
3
where a semiconductor element
2
is to be mounted, and a feed-through
4
for connecting the inside and outside of the cavity
3
. As shown in
FIGS. 9 and 10
, the feed-through
4
is divided into a coplanar line
4
a
and inner layer line
4
b
, and is comprised of a signal conductor
5
, a ground conductor
6
a
on the lower surface of a first layer substrate
1
a
, a ground conductor
6
b
of the coplanar line
4
a
, and a ground conductor
6
c
on the upper surface of a second layer substrate
1
b
(see FIG.
9
).
The cavity
3
is hermetically sealed by an upper lid
7
so that it is hermetically held (see FIG.
8
). In order to equalize electric potential, a plurality of via holes
8
a
for connecting the ground conductors
6
a
and ground conductor
6
b
to each other, and a plurality of via holes
8
b
for connecting the ground conductors
6
a
,
6
b
, and
6
c
to each other are formed along the signal propagating direction (see FIG.
9
).
As shown in
FIGS. 10 and 11
, in the structure of the conventional ceramic package, when a distance &lgr; from a connection interface c-c′ (see
FIG. 10
) between the coplanar line
4
a
and inner layer line
4
b
to the center of the endmost via hole
8
b
formed to extend through the first and second layer substrates
1
a
and
1
b
(see
FIG. 11
) increases with respect to a signal wavelength, a signal is radiated in an outward propagation mode between the connection interface c-c′ and the endmost via hole
8
b
into a plane-parallel plate, constituted by the ground conductor
6
b
of the coplanar line
4
a
and the ground conductor
6
c
on the upper surface of the second layer substrate
1
b
. Studies made by the present inventors clarified that in the conventional ceramic package, the transmission characteristics in the feed-through
4
degraded due to this signal radiation.
For example, in the prior art, when a signal up to 60 GHz is to be transmitted to a feed-through made of a dielectric substrate with a specific dielectric constant of 7.1, the distance &lgr; must be 0.3 mm or less. To form a via hole at such a short distance degrades the yield because cracking occurs in the manufacture. For this reason, it is difficult to set the distance &lgr; very small (to about up to 0.4 mm), and problems arise in the yield of the manufacture, degradation in transmission characteristics of an RF signal, and the like.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an RF package with a feed-through structure in which transmission characteristics of an RF signal do not degrade.
It is another object of the present invention to provide an RF package with a feed-through structure in which the yield in the manufacture is improved.
In order to achieve the above objects, according to the present invention, there is provided an RF package comprising a multilayered dielectric substrate on which first and second dielectric substrates are formed, the multilayered dielectric substrate having a cavity where a semiconductor element is to be mounted, a feed-through for connecting an inside and outside of the cavity and comprised of a coplanar line formed on the first dielectric substrate and an inner layer line obtained by forming the second dielectric substrate on the coplanar line, the coplanar line and the inner layer line sharing a strip-like signal conductor, and metal members formed at a connection interface between the coplanar line and the inner layer line on two sides of the signal conductor.
REFERENCES:
patent: 4908694 (1990-03-01), Hidaka et al.
patent: 5852391 (1998-12-01), Watanabe et al.
patent: 5929728 (1999-07-01), Barnett et al.
patent: 6057600 (2000-05-01), Kitazawa et al.
patent: 6215377 (2001-04-01), Douriet
patent: 6617946 (2003-09-01), Kennedy et al.
patent: 63-107055 (1988-05-01), None
patent: 63-261859 (1988-10-01), None
patent: 2-291152 (1990-11-01), None
patent: 4-312960 (1992-11-01), None
patent: 5-75313 (1993-03-01), None
patent: 5-175356 (1993-07-01), None
patent: 5-86859 (1993-12-01), None
patent: 6-112352 (1994-04-01), None
patent: 6-224604 (1994-08-01), None
patent: 8-172303 (1996-07-01), None
patent: 9-23106 (1997-01-01), None
patent: 9-321501 (1997-12-01), None
patent: 10-242716 (1998-09-01), None
patent: 10-303333 (1998-11-01), None
patent: 11-68416 (1999-03-01), None
patent: 11-312751 (1999-11-01), None
“Multichip MMIC Package for X and Ka Bands”, IEEE Transactions on Components, Packaging and Manufacturing Technology—Part B, vol. 20, Feb. 1997.
Ikuina Kazuhiro
Ito Masaharu
Maruhashi Kenichi
Ohata Keiichi
Choate Hall & Stewart
Lee Benny
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