Active solid-state devices (e.g. – transistors – solid-state diode – Housing or package – For high frequency device
Reexamination Certificate
2001-10-05
2002-12-03
Talbott, David L. (Department: 2827)
Active solid-state devices (e.g., transistors, solid-state diode
Housing or package
For high frequency device
C257S784000, C257S786000, C330S066000, C333S247000, C361S777000, C361S783000
Reexamination Certificate
active
06489680
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device. More particularly, the present invention relates to a technology effectively applicable to a semiconductor device designed into a configuration of a multistage amplifier circuit.
A semiconductor device known as a high-frequency power amplifier (or a high-frequency power module) is incorporated in a portable communication apparatus such as a portable telephone or an car telephone of the PDC (Personal Digital Cellular) system or a portable telephone of the PHS (Personal Handyphone System). This high-frequency power amplifier is designed into a configuration of a multistage amplifier circuit in which a plurality of amplifying means are electrically connected to each other to form a multistage structure.
The high-frequency power amplifier is built by mounting a semiconductor chip on a main surface of a wiring substrate.
The semiconductor chip has an amplifying means formed on a main surface thereof. Electrodes formed on a main surface of the semiconductor chip are electrically connected to electrodes formed on a main surface of the wiring substrate by conductive wires. The amplifying means has a configuration in which typically a plurality of field-effect transistors are electrically connected to each other to form a parallel circuit. A gate terminal (serving as the input unit) of the amplifying means is electrically connected to a chip-side input electrode formed on the main surface of the semiconductor chip. On the other hand, a drain terminal (serving as the output unit) of the amplifying means is electrically connected to a chip-side output electrode formed on the main surface of the semiconductor chip. The chip-side input electrode is placed at a position on a particular side of the semiconductor chip whereas the chip-side output electrode is placed at a position on another side of the semiconductor chip facing the particular side. A source terminal of the amplifying means is electrically connected to a back-surface electrode formed on a back surface of another semiconductor chip facing the main surface. The back-surface electrode is fixed at a reference electric potential. The chip-side input electrode is electrically connected to a substrate-side input electrode formed on the main surface of the wiring substrate by an input wire. The substrate-side input electrode is placed at a position facing the particular side of the semiconductor chip cited above. The chip-side output electrode is electrically connected to a substrate-side output electrode formed on the main surface of the wiring substrate by an output wire. The substrate-side output electrode is placed at a position facing the other side of the semiconductor chip cited above.
By the way, in order to reduce the size and the cost of the high-frequency power amplifier, an attempt has been made to form a plurality of amplifying means on one semiconductor chip. In the case of two amplifying means formed on one semiconductor chip, for example, the amplifying means at the front stage is oriented in a direction opposite to a direction in which the amplifying means at the rear stage is oriented so that the input and the output of the amplifying means at the front stage are placed at locations in close proximity to respectively the output and the input of the amplifying means at the rear stage. As a result, the input and output wires at the front stage and the output and input wires at the rear stage are close to each other. As a result, there is raised a problem of a deteriorating high-frequency characteristic due to a mutual-induction effect between the input and output wires. In particular, the mutual-induction effect between the input wire of the front stage and the output wire of the rear stage is a serious problem since a difference between a power flowing through the input wire and a power flowing through the output wire is big.
A technology to prevent the high-frequency characteristic from deteriorating due to a mutual-induction effect between wires is disclosed for example in Japanese Patent Laid-open No. Hei 9-260412 (1997). According to this technology, a chip-side bonding electrode is formed between the chip-side input electrode and the chip-side output electrode whereas a substrate-side bonding electrode is formed between the substrate-side input electrode and the substrate-side output electrode. The chip-side bonding electrode is electrically connected to the substrate-side bonding electrode and, by fixing the chip-side bonding electrode and the substrate-side bonding electrode at a reference electric potential, the high-frequency characteristic can be prevented from deteriorating due to a mutual-induction effect between the input and output wires.
In addition, the high-frequency power amplifier module employing transistors is a key device of a portable telephone of mobile communication adopting systems such as the PDC (Personal Digital Cellular) system and the GSM (Global System for Mobile communication). The demand for such a portable telephone has been growing tremendously in recent years. Specifications of such a high-frequency power amplifier include a small size and a low cost in addition to good high-frequency characteristics for applications to mobile communication systems.
A technique to respond to such a demand is disclosed in Japanese Patent Laid-open No. 2755250. By placing 2 transistors, namely, a first-stage transistor
2000
and a second-stage transistor
3000
, at locations close to each other on a semiconductor chip
1000
as shown in a top-view diagram of
FIG. 21 and a
squint-view diagram of
FIG. 22
, the size and the cost can be reduced. A bonding input electrode
2000
b
of the first-stage transistor
2000
is electrically connected to a bonding electrode
7000
d
of a wiring substrate
6000
by an input bonding wire
9000
d
. A bonding output electrode
3000
c of the second-stage transistor
3000
is electrically connected to a bonding electrode
7000
a
of the wiring substrate
6000
by an output bonding wire
9000
a
. A bonding electrode
10000
a
on the semiconductor chip
1000
is electrically connected to a bonding electrode
12000
a
of the wiring substrate
6000
by a shield bonding wire
13000
a
. The shield bonding wire
13000
a
is provided between the input bonding wire
9000
d
and the output bonding wire
9000
a
. The bonding electrode
10000
a
and the bonding electrode
12000
a
at the ends of the shield bonding wire
13000
a
are connected to the ground at high frequencies by via holes bored through the semiconductor chip
1000
and the wiring substrate. It should be noted that the via holes themselves are not shown in the figure. By providing a shield bonding wire
13000
a
, the amount of coupling through a mutual inductance between the input bonding wire
9000
d
and the output bonding wire
9000
a
can be reduced, allowing the degree of deterioration of isolation between the high-frequency input and output terminals to be lowered. As a result, the high-frequency characteristic is improved.
The problem of coupling through a mutual inductance between the input bonding wire
9000
d
and the output bonding wire
9000
a
is raised by a location of the input of the first-stage transistor
2000
in close proximity to a location of the output of the second-stage transistor
3000
and a location of the output of the first-stage transistor
2000
in close proximity to the location of the input of the second-stage transistor
3000
which are caused by the fact that the first-stage transistor
2000
and the second-stage transistor
3000
are oriented in directions opposite to each other. In particular, the mutual-induction effect between the input bonding wire
9000
d
of the first-stage transistor
2000
and the output bonding wire
9000
a
of the second-stage transistor
3000
is a serious problem. This is because the high-frequency power output by the second-stage transistor
3000
is higher than the high-frequency power input to the first-stage transistor
2000
by 20 to 30 dB (or 100 to 1,000 t
Adachi Tetsuaki
Hase Eiichi
Kagaya Osamu
Kikuchi Sakae
Kohjiro Iwamichi
Hitachi , Ltd.
Mattingly Stanger & Malur, P.C.
Talbott David L.
Vigushin John B.
LandOfFree
Semiconductor device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2978696