SEMICONDUCTOR DEVICE, LEAD FRAME, AND MICROPHONE PACKAGE
THEREFOR
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to semiconductor devices having sensor chips
and lead frames, which are encapsulated in microphone packages.
The application claims priority on Japanese Patent Application No.
2007-206724, the content of which is incorporated herein by reference.
Description of the Related Art
In conventionally-known semiconductor devices, sensor chips (for sensing
sounds and the like) are incorporated into the hollow cavities defined by substrates and
covers and are mounted on the surfaces of substrates. Various types of
semiconductor devices have been disclosed in various documents such as Patent
Document 1.
Patent Document 1: Japanese Unexamined Patent Application Publication No.
2007-66967
Patent Document 1 teaches a semiconductor device having a substrate which
includes a rectangular stage for mounting a sensor chip thereon, a plurality of leads
arranged in the surrounding area of the stage, and a resin layer, which is molded so as
to seal the stage and the leads. Herein, the stage for mounting a sensor chip is
partially exposed from the resin layer, and the distal ends of the leads electrically
connected to the sensor chip via wires are exposed externally of the resin layer,
wherein an opening of a cover is formed in the resin layer surrounding the surface of
the stage.

Since the stage and the cover have conductive property, it is possible to shield
electromagnetic noise from entering in to the hollow cavity by means of the stage and
the cover. This avoids erroneous operation of the sensor chip due to electromagnetic
noise.
The aforementioned semiconductor device suffers from a gap between the
periphery of the stage and the cover and gaps between the leads adjoining together,
wherein these gaps are not completely covered with the stage and the cover. Hence,
it is likely that electromagnetic noise may enter into the cavity via the gaps.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a semiconductor device,
which is designed to reduce gaps allowing electromagnetic noise to enter into a cavity
by use of resin mold technology, thus achieving shield performance substantially
equivalent to that of a ceramic package.
It is another object of the present invention to provide a lead frame for use in
the semiconductor device.
It is a further object of the present invention to provide a microphone package
adapted to the semiconductor device.
In a first aspect of the present invention, a semiconductor device includes a
sensor chip, a mold sheet having a rectangular shape in a plan view and including a
stage having a conductive property, in which a plurality of cutouts is formed in the
periphery thereof, a plurality of lead terminals each having a conductive property
which is arranged inside of the plurality of cutouts and is electrically connected to the
sensor chip, and a resin mold having an insulating property which is formed to
electrically insulate the stage from the plurality of lead terminals, and a cover having

an opening and a box-like shape, which is combined with the mold sheet so as to form
a cavity therebetween. The sensor chip is mounted on the surface of the stage which
forms the same plane as the surface of the mold sheet. The lead terminals include
connection portions having internal connection surfaces, which are exposed in the
cavity and are electrically connected to the sensor chip, and support leads which are
elongated from the connection portions towards the stage so that the distal ends thereof
are exposed on the side surface of the mold sheet. In the prescribed portions of the
support leads positioned in the cutouts, the recesses are formed and recessed in width
directions thereof and are sealed with the mold resin. The opening end of the cover is
fixed onto the mold sheet above the recesses of the support leads sealed with the resin
mold.
In the above, the sensor chip is electrically connected to the internal
connection surfaces of the lead terminals, which are exposed in the cavity, via wires.
The recesses of the lead terminals are sealed with the resin mold and are not exposed
on the surface of the mold sheet; hence, the lead terminals are electrically insulated
from the cover.
The opening end of the cover is brought into contact with the surface of the
mold sheet so that the stage is electrically connected to the cover. When the
semiconductor device is mounted on a substrate (or a circuit board) having a ground
pattern, the stage and the cover are electrically connected to the ground pattern so as to
form a shield structure for blocking electromagnetic noise from entering into the cavity.
The shield structure entirely covers the cavity except for the cutouts of the stage that
are not brought into contact with the cover; hence, it is possible to minimize gaps
allowing electromagnetic noise from entering into the cavity.
In a second aspect of the present invention, a lead frame, which is produced

using a thin metal plate, includes a stage having a rectangular shape in a plan view for
mounting a sensor chip thereon, a plurality of lead terminals which are electrically
connected to the sensor chip and which have a plurality of connection portions
integrally connected with the stage, a plurality of cutouts which are formed in the
periphery of the stage so as to arrange the lead terminals and the connection portions
therein, and a plurality of support leads which are externally elongated from the
connection portions. A plurality of recesses is formed on the support leads inside of
the cutouts.
The mold sheet for use in the semiconductor device can be easily produced
using the aforementioned lead frame. Specifically, the stage and the lead terminals
are clamped by a metal mold in the thickness direction; then, a melted resin composed
of an insulating material is injected into a cavity formed between the recesses of the
support leads of the lead terminals and the interior surface of the metal mold so as to
form the resin mold for sealing the stage and the lead terminals. Herein, the recesses
are sealed with the resin mold while the surface of the stage is exposed from the resin
mold, wherein the surface of the stage forms the same plane as the surface of the mold
sheet. When the opening end of the cover is mounted on the recesses sealed with the
resin mold, it is possible to prevent the lead terminals from coming into contact with
the cover.
In this connection, the stage and the lead terminals are integrally formed using
the lead frame produced using the thin metal plate, wherein the recesses are formed by
partially etching the surface of the thin metal plate substantially corresponding to the
surface of the stage, and wherein the stage is formed by partially etching the backside
of the thin metal plate and is thus reduced in thickness so that the lower side of the
stage is sealed with the resin mold. In the lead frame, the recesses are formed by

partially etching the surface of the thin metal plate, and the stage is formed by partially
etching the backside of the thin metal plate.
In the mold sheet forming step, even when the stage and the lead terminals are
clamped by the metal mold in the thickness direction, it is possible to prevent the stage
and the lead terminals from being deformed; thus, it is possible to easily produce the
semiconductor device. When the lead terminals are subjected to press working or
bending while the stage is upset so that the recesses are positioned lower than the
surface of the stage, the connection portions and bent portions of the lead terminals
may be easily deformed during clamping of the lead frame by the metal mold so that
the stage and the lead terminals may be partially distanced from the interior surface of
the metal mold, whereby resin burrs may be formed in boundaries between the stage,
the lead terminals, and the metal mold. In contrast, the present invention is designed
such that the stage and the recesses are formed via etching; hence, it is possible to
prevent the stage and the lead terminals from being deformed during the formation of
the resin mold; thus, it is possible to easily avoid the formation of resin burrs.
In this connection, the thickness of the resin mold (for sealing the stage and
the lead terminals) is substantially identical to the original thickness of the thin metal
plate prior to etching; hence, it is possible to reduce the overall thickness of the
semiconductor device.
Alternatively, the connection portions of the lead terminals can be formed by
etching the backside of the thin metal plate so that the lower sides of the connection
portions are sealed with the resin mold. In this case, the lead terminals are clamped
in the thickness direction by the metal mold; hence, it is possible to improve the
engagement between the lead terminals and the resin mold; in other words, it is
possible to prevent the lead terminals from being unexpectedly separated from the

resin mold.
The mold sheet has a ground terminal (having a conductive property) which is
formed integrally with the stage so as to project from the backside of the stage and
which is electrically connected to the sensor chip. The external connection surface of
the ground terminal is exposed from the resin mold below the stage. The
aforementioned shield structure can be formed by simply bringing the ground terminal
in contact with the ground pattern of the substrate. That is, the stage engages with
the resin mold via the ground terminal. In other words, it is possible to improve the
engagement between the stage and the resin mold due to the anchor effect of the
ground terminal; hence, it is possible to prevent the stage from being separated from
the resin mold.
The sensor chip is a microphone chip having a sound detector for detecting
pressure variations, for example. A sound hole allowing the cavity to communicate
with the external space can be formed to run through the cover. The sound hole
allows pressure variations (e.g. variations of sound pressures) to enter into the cavity
and to reach the sound detector, which thus detect pressure variations.
In a third aspect of the present invention, a microphone package includes a
microphone chip, a mold sheet having a rectangular shape in a plan view and including
a stage having a conductive property, in which a plurality of cutouts is formed in the
periphery thereof, a plurality of lead terminals each having a conductive property
which is arranged inside of the cutouts and is electrically connected to the microphone
chip, and a resin mold having an insulating property which is formed to electrically
insulate the stage from the lead terminals, and a cover having a box-like shape, which
is combined with the mold sheet so as to form a housing including a cavity and a
sound hole. The lead terminals are arranged inside of the cutouts and are thus

electrically insulated from the stage via the resin mold. The lead terminals include a
ground terminal formed integrally with the stage and a plurality of internal connection
surfaces electrically connected to the microphone chip. The stage and the lead
terminals are sealed with the resin mold such that the surface of the stage and the
internal connection surfaces are exposed from the mold sheet in the housing. The
cover is electrically insulated from the lead terminals and is electrically connected to
the stage.
In the above, the microphone chip is electrically connected to the internal
connection surfaces of the lead terminals, which are exposed in the housing, via wires.
By electrically connecting the external connection surface of the ground terminal to
the ground pattern of the substrate (for mounting the microphone package), it is
possible to form the shield structure (for blocking electromagnetic noise from entering
into the cavity) by means of the cover and the stage. The shield structure entirely
covers the cavity except for the cutouts of the stage which do not come in contact with
the lead terminals; hence, it is possible to minimize gaps allowing electromagnetic
noise from entering into the cavity.
In the microphone package, the mold sheet includes a lead frame, which is
produced using a thin metal plate, wherein the lead terminals have support leads which
are externally extended from the periphery of the stage so that the distal ends thereof
are exposed on the side surface of the mold sheet. The support leads have recesses,
which are sealed with the insulating resin mold relative to the surface of the mold
sheet so as to mount the opening end of the cover.
The lead frame is equipped with a frame so that the support leads extended
from the lead terminals join the frame. The recesses are formed by performing
half-etching on the support leads. The stage is interconnected with a plurality of

interconnection leads which are externally extended from the periphery of the stage so
that the distal ends thereof are exposed on the side surface of the mold sheet. The
lead frame is sealed with the resin mold such that the recesses of the support leads are
sealed with the resin mold. The mold sheet is subjected to cutting so as to cut out the
interconnection leads.
In the mold sheet forming step, it is possible to prevent the stage and the lead
terminals from being deformed during the formation of the resin mold by claming the
lead frame in the thickness direction; hence, it is possible to easily produce the
microphone package.
The interconnection leads are externally extended from the periphery of the
stage so that the distal ends thereof are exposed on the side surface of the mold sheet
in the microphone package, wherein they are brought into contact with the cover when
the cover is fixed onto the mold sheet. Herein, the cover can be directly and
electrically connected to the stage.
As described above, the present invention can minimize the gaps allowing
electromagnetic noise from entering into the cavity; hence, it is possible to further
improve the shield effect of the semiconductor device and the microphone package.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, aspects, and embodiments of the present invention
will be described in more detail with reference to the following drawings.
FIG. 1 is a plan view of a semiconductor device in view of the surface of a
resin mold in accordance with a preferred embodiment of the present invention.
FIG. 2 is a plan view of the semiconductor device in view of the backside of
the resin mold.

FIG. 3 is a longitudinal sectional view taken along line A-A in FIGS. 1 and 2.
FIG. 4 is a plan view showing a lead frame for use in the semiconductor
device in view of the surface of a thin metal plate.
FIG. 5 is a plan view showing the lead frame in view of the backside of the
thin metal plate.
FIG. 6 is a plan view showing the lead frame sealed with a resin mold in view
of the surface of the thin metal plate.
FIG. 7 is a plan view showing the lead frame sealed with the resin mold in
view of the backside of the thin metal plate.
FIG. 8 is a cross-sectional view taken along line B-B in FIGS. 6 and 7.
FIG. 9 is an enlarged cross-sectional view showing essential parts of the
semiconductor device which is partially modified.
FIG. 10 is a longitudinal sectional view showing the semiconductor device
which is further modified.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will be described in further detail by way of examples
with reference to the accompanying drawings.
A semiconductor device 1 according to a preferred embodiment of the present
invention will be described with reference to FIGS. 1 to 8. The semiconductor device
1 is designed to detect variations of pressures such as sound pressures generated in the
external space and is a surface mount type produced using a lead frame.
As shown in FIGS. 1 to 3, the semiconductor device 1 is constituted using a
mold sheet 3 having a rectangular shape in a plan view, a microphone chip (or a sensor
chip) 5 and a companion chip 7 formed on a surface 3a of the mold sheet 3, and a

cover 9 which is arranged above the mold sheet 3 so as to cover the microphone chip 5
and the companion chip 7.
The mold sheet 3 is constituted of a stage 11 which has a rectangular shape in
a plan view so as to form the surface 3a of the mold sheet 3, a plurality of lead
terminals (e.g. three lead terminals serving as conductive portions) 13, and a resin
mold (or an insulating portion) 15 for molding the stage 11 and the lead terminals 13.
Both the stage 11 and the lead terminals 13 having conductive properties are formed
using a lead frame which is composed of a thin metal plate.
The surface 3 a of the mold sheet 3 corresponding to the surface of the stage
11 is exposed externally of a surface 15a of the resin mold 15. A backside 11b of the
stage 11 is sealed with the resin mold 15. In the present embodiment, the surface of
the stage 11 and the surface 15a of the resin mold 15 form the same plane, i.e. the
surface 3 a of the mold sheet 3 for mounting the microphone chip 5 and the companion
chip 7 thereon.
A plurality of cutouts (e.g. three cutouts) 17 are formed to cut into the stage
11 from its peripheral end. The lead terminals 13 are partially arranged inside of the
cutouts 17. Each of the cutouts 17 are increased in area inside of the stage so that an
opening 17a thereof is narrower than the bottom of the cutout 17 in width dimensions.
In the present embodiment, two of the three cutouts 17 are aligned along a first side
11c of the stage 11, while the remaining one cutout 17 is arranged along a second side
11d (which is opposite to the first side 11c) of the stage 11 and is positioned opposite
to one of the two cutouts 17 aligned along the first side 11c of the stage 11.
A plurality of interconnection leads (e.g. three interconnection leads) 19 are
extended from the peripheral end of the stage 11 towards a side surface 4 of the resin
mold 15. Together with the surface 3a of the stage 11, the interconnection leads 19

are exposed externally of the surface 15a of the resin mold 15.
In the present embodiment, one interconnection lead 19 is formed along the
second side 11d of the stage 11 in such a way that it is aligned together with one cutout
17 along the second side 1 1d and is positioned opposite to the other of the two cutouts
17 aligned along the first side 11 c of the stage 11. The other two interconnection
leads 19 are formed along the respective sides of the stage 11 which are perpendicular
to the first side 11c and the second side 11d, wherein they are positioned opposite to
each other.
A ground terminal 21 that projects from the backside 11b of the stage 11 is
integrally formed together with the stage 11. The distal end of the ground terminal
21 is exposed externally of the resin mold 15. Specifically, an external connection
surface 21b of the ground terminal 21 forms the same plane with a backside 15b of the
resin mold 15 substantially matching the backside of the mold sheet 3. When the
semiconductor device 1 is mounted on a substrate (or a circuit board, not shown), the
ground terminal 21 is electrically connected to a ground pattern (or an external wire,
not shown) via solder.
Each of the lead terminals 13 arranged inside of the cutouts 17 of the stage 11
is constituted of a connection portion 13a (having an internal connection surface 14a
electrically connected to the companion chip 7) and a support lead 18 (having a
plate-like shape elongated externally from the stage 11), so that each of them is not
placed in contact with the stage 11. The support lead 18 is arranged in the opening
17a of the cutout 17 so as to project externally from the peripheral portion of the stage
11, wherein the distal end of the support lead 18 is exposed on the side surface 4 of the
resin mold 15. The support lead 18 is narrower than the connection portion 13a in
width dimensions.

The lead terminals 13 have external connection surfaces 14b, which are
exposed externally of the resin mold 15 and are electrically connected to external
wires (not shown). The external connection surfaces 14b of the lead terminals 13
form the same plane together with the backside 15b of the resin mold 15. In the
present embodiment, the external connection surface 14b entirely covers the backside
of the connection portion 13a and the backside of the support lead 18.
As described above, the lead terminals 13 are formed to integrally combine
the internal connection surfaces 14a and the external connection surfaces 14b. When
the semiconductor device 1 is mounted on a substrate (or a circuit board, not shown),
the lead terminals 13 serve as external connection terminals for electrically connecting
the microphone chip 5 and the companion chip 7 to connection terminals (or external
wires) of the substrate via solder.
All the stage 11, the support leads 18, and the interconnection leads 19 are
formed by way of half-etching applied to the foregoing thin metal plate; hence, they
have very thin portions that are thinner than the mold sheet 3.
The support leads 18 of the lead terminals 13 are formed by etching the
surface of the thin metal plate (forming the surface 3 a of the stage 11 and the internal
connection surfaces 14a of the connection portions 13 a); hence, they have
approximately half of the original thickness of the thin metal plate. For this reason,
the support leads 18 are positioned lower than the surface 3a of the stage 11. That is,
the support leads 18 form a recess 24 which is recessed from the surface of the mold
sheet 3 for mounting the cover 9.
The stage 11 and the interconnection leads 19 are formed by etching the
backside of the thin metal plate, wherein the thickness of the corresponding portions is
reduced approximately a half the original thickness of the thin metal plate. In the

stage 11, the ground terminal 21 is not subjected to the foregoing half etching, so that
the thickness thereof is identical to the original thickness of the thin metal plate. That
is, the thickness of the ground terminal 21 is identical to the thickness of the
prescribed parts of the resin mold 15 formed inside of the cutouts 17. The connection
portions 13a of the lead terminals 13 are not subjected to half etching, so that the
thickness thereof is identical to the original thickness of the thin metal plate.
The resin mold 15 is composed of an electrically insulating material, wherein
it is formed to cover the backside 11b of the stage 11, the lower surfaces of the
interconnection leads 19, and the recesses 24 of the support leads 18. In addition, the
resin mold 15 is also formed to seal the gaps between the stage 11 and the lead
terminals 13 arranged inside of the cutouts 17. The surface 3a of the stage 11 and the
internal connection surfaces 14a of the lead terminals 13 are exposed externally of the
surface 15a of the resin mold 15. The external connection surfaces 14b of the lead
terminals 13 and the external connection surface 21b of the ground terminal 21 are
exposed externally of the backside 15b of the resin mold 15.
As described above, the thickness of the prescribed portions of the resin mold
15 sealing the gaps between the stage 11 and the lead terminals 13 arranged inside of
the cutouts 17 is substantially identical to the thickness of the thin metal plate prior to
foregoing half-etching, whereby the thickness of the mold sheet 3 is substantially
identical to the thickness of the thin metal plate.
The cover 9 composed of a conductive material such as copper is formed in a
box-like shape having a bottom. The cover 9 is arranged to cover the resin mold 15
formed on the surface 3a of the stage 11 and the recesses 24 of the support leads 18.
Herein, an opening end 9a of the cover 9 (which is integrally formed together with the
center portion of the cover 9 having the sound hole 9b) is placed on the periphery of

the surface 3a of the stage 11 and the prescribed portions of the resin mold 15 formed
inside of the openings 17a of the cutouts 17. The opening end 9a of the cover 9 is
bonded and fixed onto the surface 3 a of the stage 11 via a conductive bonding material
32. This makes it possible to electrically connect the stage 11 to the cover 9.
The support leads 18 arranged in the openings 17a of the cutouts 17 are sealed
with the resin mold 15 which forms the same plane as the surface 3 a of the stage 11
and are thus not exposed from the surface 3 a of the stage 11; hence, the lead terminals
13 are electrically insulated from the cover 9.
By arranging the cover 9 on the mold sheet 3, the hollow cavity S1
incorporating the microphone chip 5 and the companion chip 7 is defined between the
cover 9 and the mold sheet 3. That is, the cover 9 is combined together with the mold
sheet 3 so as to form a housing having the hollow cavity S1.
The surface 3 a of the stage 11 and the internal connection surfaces 14a of the
connection portions 13a of the lead terminals 13 are exposed inside of the cavity S1
from the resin mold 15. That is, the internal connection surfaces 14a electrically
insulated from the stage 11 are exposed inside of the housing. The sound hole 9b
allowing the cavity S1 to communicate with the external space is formed at the
prescribed position of the cover 9.
The microphone chip 5 is basically composed of silicon and converts pressure
variations such as variations of sound pressures into electric signals, wherein it has s
sound detector 5a that vibrates in response to pressure variations. The microphone
chip 5 translates vibrations of the sound detector 5 as variations of electric resistance;
hence, it produces electric signals based on variations of resistance or variations of
capacitance.
The microphone chip 5 is bonded and fixed onto the stage 11 via an insulating

bonding paste (not shown) in such a way that the sound detector 5a is positioned
opposite to the surface 3 a of the stage 11. That is, a cavity S2 is formed between the
sound detector 5a of the microphone chip 5 and the surface 3 a of the stage 11.
The companion chip 7 drives and controls the microphone chip 5, wherein it
includes an amplifier for amplifying electric signals output from the microphone chip
5, an A/D converter for converting electric signals into digital signals, and a digital
signal processor (DSP). Similar to the microphone chip 5, the companion chip 7 is
fixed onto the surface 3 a of the stage 11 via an insulating bonding paste (not shown).
The companion chip 7 is electrically connected to the microphone chip 5 via
first wires (or internal wires) 23 and is electrically connected to the internal connection
surfaces 14a of the lead terminals 13 via second wires (or internal wires) 25. In
addition, the companion chip 7 is electrically connected to the surface 3 a of the stage
11 via a third wire 27. Thus, the microphone chip 5 is electrically connected to the
stage 11 and the lead terminals 13 by way of the companion chip 7.
When pressure variations (e.g. variations of sound pressures) enter into the
cavity S1 via the sound hole 9b of the cover 9, they reach the sound detector 5a of the
microphone chip 5. That is, the semiconductor device 1 forms a microphone package
for detecting pressure variations.
Next, a manufacturing method of the semiconductor device 1 will be
described in detail.
In the manufacturing of the semiconductor device 1, a mold sheet producing
step is firstly performed so as to produce the mold sheet 3. In the mold sheet
producing step, as shown in FIGS. 4 and 5, the thin metal plate 31 composed of copper
is subjected to press working and/or etching so as to perform a lead frame forming step,
in which the lead frame 33 is formed in such a way that the lead terminals 13 and the

interconnection leads 19 project inwardly of the frame 35, and the interconnection
leads 19 are integrally connected with the stage 11 having a rectangular shape in a plan
view (which is arranged inside of the frame 35). In the lead frame 33, the frame 35
and the interconnection leads 19 serve as interconnection means for integrally
interconnecting the stage 11 and the lead terminals 13.
In the lead frame forming step, the cutouts 17 are formed in the stage 11 such
that they are cut into from the periphery of the surface 3 a of the stage 11
(corresponding to the surface 31a of the thin metal plate 31), wherein they are
positioned such that the connection portions 13a of the lead terminals 13 do not come
in contact with the stage 11, and the support leads 18 do not partially come in contact
with the stage 11. That is, a plurality of cutouts 17 is formed in the stage 11 having a
rectangular shape in a plan view such that they are cut into from the periphery of the
stage 11. In addition, the lead terminals 13 are arranged inside of the cutouts 17 with
prescribed distances therebetween so as to allow the stage 11 to be molded with a resin
while being electrically insulated from the internal connection surfaces 14a and the
external connection surfaces 14b.
Next, a half-etching step is performed such that the support leads 18 of the
lead terminals 13, the stage 11, and the interconnection leads 19 are subjected to half
etching. In this step, half-etching is performed on the surface 31a of the thin metal
plate 31 so as to entirely reduce the thickness of the support leads 18 (see hatched
areas in FIG. 4) to be smaller than the original thickness of the thin metal plate 31.
This forms the recesses 24 of the support leads 18, which are recessed from the
prescribed surface for mounting the opening end 9a of the cover 9.
In this step, half-etching is performed on the backside 31b of the thin metal
plate 31, so that a relatively large part of the thin metal plate 31 including the stage 11

and the interconnection leads 19 (see hatched area shown in FIG. 5) except for the
ground terminal 21 is reduced in thickness compared with the original thickness of the
thin metal plate 31.
This half-etching step can be performed simultaneously with the lead frame
forming step; alternatively, it can be performed before or after the lead frame forming
step. The lead frame 33 can be formed using a single sheet of the thin metal plate 31;
alternatively, it can be formed using multiple sheets laminated together.
After completion of the lead frame forming step and the half-etching step, the
lead frame 33 is molded with the resin mold 15 as shown in FIGS. 6 to 8. In this
molding step, the lead frame 33 is clamped in the thickness direction by means of a
metal mold (not shown) used for the formation of the resin mold 15, wherein a cavity
is formed between the thinned portion of the lead frame 33 (whose thickness is
reduced compared with the original thickness of the thin metal plate 31 in the
half-etching step) and the interior surface of the metal mold. A melted resin
(composed of an insulating material) is injected into the cavity of the metal mold, thus
forming the resin mold 15.
Thereafter, the lead terminals 13 and the interconnection leads 19 (which are
molded with the resin mold 15) are subjected to cutting and are thus separated from
the frame 35 (which is positioned outside of the resin mold 15). This cutting step
ends the production of the mold sheet 3. Separation is achieved by cutting the
prescribed portion of the resin mold 15 positioned between the stage 11 and the frame
35, whereby the distal ends of the support leads 18 and the distal ends of the
interconnection leads 19 are exposed on the cut surface.
Hatched areas shown in FIG. 6 indicate the resin mold 15 (which is formed in
the molding step) in view of the surface 3a of the stage 11. As shown in FIGS. 6 and

8, the surface 3 a of the stage 11, the internal connection surfaces 14a of the connection
portions 13a of the lead terminals 13, and the interconnection leads 19 are exposed
from the resin mold 15 in the same plane as the surface 15a of the resin mold 15.
Gaps between the stage 11 and the frame 35 and gaps between connection portions 13a
(arranged inside of the cutouts 17 of the stage 11) and the support leads 18 are also
filled with the resin. In addition, the upper portions of the support leads 18 are
covered with the resin mold 15.
The hatched area shown in FIG. 7 indicates the resin mold 15 (which is
formed in the molding step) in view of the backside of the stage 11. As shown in
FIGS. 7 and 8, the external connection surfaces 14b of the lead terminals 13 and the
external connection surface 21b of the ground terminal 21 are exposed from the resin
mold 15 in the same plane as the backside 15b of the resin mold 15. In addition, the
backside 11b of the stage 11 and the lower portions of the interconnection leads 19 are
covered with the resin mold 15.
In this mold sheet forming step, the mold sheet 3 is formed with the same
thickness as the original thickness of the thin metal plate 31.
After completion of the mold sheet forming step, a chip mounting step is
performed as shown in FIGS. 1 to 3 such that the microphone chip 5 and the
companion chip 7 are fixed onto the stage 11 (forming the surface 3a of the mold sheet
3) via an insulating bonding paste (not shown). Next, an electric connection step is
performed such that the microphone chip 5 is electrically connected to the companion
chip 7 via the first wires 23 by way of wire bonding, the companion chip 7 is
electrically connected to the internal connection surfaces 14a of the lead terminals 13
via the second wires 25, and the companion chip 7 is electrically connected to the
surface 3 a of the stage 11 via the third wire 27.

Lastly, the cover 9 is fixed onto the periphery of the surface 3 a of the stage 11
such that the microphone chip 5 and the companion chip 7 are completely covered
with the cover 9. This cover fixing step completes the production of the
semiconductor device 1.
In the cover fixing step, the cover 9 is fixed onto the mold sheet 3 via the
conductive bonding material 32. Due to the cover fixing step, the opening end 9a of
the cover 9 is arranged across the openings 17a of the cutouts 17 in the width direction,
whereas the recesses 24 of the support leads 18 are positioned lower than the surface
3a of the stage 11. The recesses 24 of the support leads 18 are sealed with the
prescribed portions of the resin mold 15; hence, it is possible to prevent the lead
terminals 13 from easily coming in contact with the cover 9.
The manufacturing method of the semiconductor device 1 can be partially
modified such that the cutting step of the mold sheet forming step is performed in the
prescribed time period between the chip mounting step and the cover fixing step.
When the semiconductor device 1 (which is manufactured in accordance with
the aforementioned manufacturing method) is mounted on a substrate (or a circuit
board, not shown), the backside 15b of the resin mold 15 is positioned opposite to the
surface of the substrate, then, the lead terminals 13 and the ground terminal 21 are
electrically connected to lands of the substrate via solder.
Thus, the cover 9 and the stage 11 are electrically connected to the ground
pattern of the substrate, thus forming a shield structure for blocking electromagnetic
noise from entering into the cavity S1 defined by the cover 9 and the stage 11. The
shield structure entirely covers the cavity S1 except for the cutouts 17 (in which the
cover 9 does not come in contact with the stage 11) and the sound hole 9b of the cover
9; hence, it is possible to minimize gaps allowing electromagnetic noise to enter into

the cavity S1. The semiconductor device 1 having the lead frame 33 according to the
present embodiment can improve the shield performance.
In the semiconductor device 1 having the lead frame 33, the stage 11,
half-etching is performed on the interconnection leads 19, and the support leads 18 of
the lead terminals 13, so that no bent portion is formed in the lead terminals 13 and the
like. This reliably prevent the stage 11 and the lead terminals 13 from being
unexpectedly deformed in the molding step in which the lead frame 33 is clamped in
the thickness direction by the metal mold. This simplifies the production of the
semiconductor device 1.
By way of press working, it may be possible to bend the lead terminals 13 and
the interconnection leads 19; then, the stage 11 is upset so that the lead terminals 13
except for the connection portions 13a are positioned lower than the surface 3 a of the
stage 11. However, in the molding step in which the stage 11 and the lead terminals
13 are clamped by the metal mold, the bent portions of the lead terminals 13 and the
bent portions of the interconnection leads 19 are deformed so that the stage 11 and the
lead terminals 13 may be partially distanced from the interior wall of the metal mold.
In this case, resin burrs may be formed in boundaries between the stage 11 and the
interconnection leads 19 and in boundaries between the lead terminals 13 and the resin
mold 15.
In contrast, the present embodiment is characterized in that the stage 11 and
the lead terminals 13 except for the connection portions 13a are reduced in thickness
compared with the original thickness of the thin metal plate 31. This prevents the
stage 11 and the lead terminals 13 from being unexpectedly deformed in the molding
step; hence, it is possible to easily avoid the formation of resin burrs.
Since the thickness of the resin mold 15 for molding the stage 11 and the lead

terminals 13 is substantially identical to the original thickness of the thin metal plate
31, it is possible to easily reduce the overall thickness of the semiconductor device 1.
Since the prescribed part of the resin mold 15 is formed in the surrounding
area of the ground terminal 21 (which projects from the backside lib of the stage 11),
the stage 11 engages with the resin mold 15 via the ground terminal 21. This
improves the engagement between the stage 11 and the resin mold 15; hence, it is
possible to prevent the stage 11 from being unexpectedly separated from the resin
mold 15.
It is possible to introduce another method for improving the engagement
between the stage 11 and the resin mold 15. For example, a through-hole is formed at
a prescribed position of the stage 11 in the thickness direction in the prescribed area
except for the regions for mounting the microphone chip 5 and the companion chip 7
and is sealed with the resin mold 15. The resin formed in the through-hole provides
an anchor effect, by which the engagement between the stage 11 and the resin mold 15
can be further improved. It is preferable that the through-hole be formed at a
prescribed position of the stage 11 which does not degrade the shield performance of
the semiconductor device 1.
In the present embodiment, the connection portions 13a of the lead terminals
13 have a thickness substantially identical to the original thickness of the thin metal
plate 31 prior to etching; but this is not a restriction. For example, as shown in FIG. 9,
the connection portions 13a of the lead terminals 13 are reduced in thickness to
approximately half of the original thickness of the thin metal plate 31 such that the
connection portions 13a are recessed from the external connection surfaces 14b. That
is, it is possible to form recessed steps, which are recessed from the backside 15b of
the mold sheet 3, in the surrounding areas of the external connection surfaces 14b of

the lead terminals 13. In this case, the lower sides of the connection portions 13a are
additionally sealed with the resin mold 15 while the recesses 24 of the support leads 18
(which are formed integrally with the connection portions 13 a) are sealed with the
resin mold 15; hence, the lead terminals 13 are vertically held in the thickness
direction by the resin mold 15. This further improves the engagement between the
lead terminals 13 and the resin mold 15; hence, it is possible to easily prevent the lead
terminals 13 from being unexpectedly separated from the resin mold 15.
In the present embodiment, the interconnection leads 19 (which are integrally
formed together with the stage 11) are exposed externally of the surface 15a of the
resin mold 15; but this is not a restriction. For example, it is possible to partially
modify the semiconductor device 1 as shown in FIG. 10 such that the interconnection
leads 19 are not exposed externally of the surface 15a of the resin mold 15 but are
exposed externally of the backside 15b of the resin mold 15. That is, similar to the
support leads 18, the interconnection leads 19 are processed by performing
half-etching on the surface of the thin metal plate 31. In other words, the surfaces of
the interconnection leads 19 are recessed from the surface 3 a of the mold sheet 3 for
mounting the opening end 9a of the cover 9.
In this case, the upper sides of the interconnection leads 19 and the lower side
of the stage 11 are sealed with the resin mold 15; in other words, the stage 11 and the
interconnection leads 19 (both of which are integrally formed together) are vertically
held by the resin mold 15 in the thickness direction. Thus, it is possible to further
improve the engagement between the stage 11 and the resin mold 15.
In the case above, similar to the support leads 18 which project outside of the
periphery of the stage 11, the interconnection leads 19 interconnected with the frame
35 are exposed from the backside 15b of the resin mold 15 in the lead frame 33; hence,

it is possible to easily and rapidly divide the mold sheet 3 into individual pieces by
way of press working. In short, it is possible to improve the manufacturing efficiency
with regard to semiconductor devices.
In this connection, the interconnection leads 19 can be formed to partially
overlap with the ground terminal 21 as shown in FIG. 10.
In the present embodiment, the lead terminals 13 are aligned along the first
side 11c and the second side 11d of the stage 11 having a rectangular shape in a plan
view; but this is not a restriction. For example, the semiconductor device 1 can be
modified such that the lead terminals 13 are aligned along only the first side 11c of the
stage 11. In this case, no lead terminal 13 is formed along the other three sides of the
stage 11. This eliminates the necessity of forming the cutouts 17 arranging the lead
terminals 13; hence, no gap is formed due to the cutouts 17 between the stage 11 and
the cover 9 along the other three sides of the stage 11. This reliably blocks
electromagnetic noise from entering into the cavity S1 via the other three sides of the
stage 11.
In the above, it is preferable that a plurality of ground terminals (similar to the
ground terminal 21 that projects from the backside 11b of the stage 11) is aligned in
proximity to and along the second side 11d of the stage 11. Due to the
aforementioned alignment of multiple ground terminals, it is possible to mount the
semiconductor device 1 on the substrate in a stable manner.
In the present embodiment, both the microphone chip 5 and the companion
chip 7 are fixed onto the surface 3 a of the stage 11 via the insulating bonding paste;
but this is not a restriction. The present embodiment simply requires that they are
mounted on the surface 3a of the stage 11. That is, the semiconductor device 1 is
partially modified such that the microphone chip 5 and the companion chip 7 are fixed

onto the surface of a base mold (composed of a resin) which is additionally formed on
the surface 3 a of the stage 11.
The base mold can be formed simultaneously with the resin mold 15 in the
mold sheet forming step. Herein, it is necessary that the base mold be formed at a
prescribed position evading certain region of the surface 3 a of the stage 11 vertically
overlapping the opening end 9a of the cover 9.
In the present embodiment, the opening end 9a of the cover 9 is arranged on
the periphery of the surface 3 a of the stage 11; but this is not a restriction. The
present embodiment simply requires the opening end 9a of the cover 9 to be arranged
on the surface 3a of the stage 11 such that the microphone chip 5, the companion chip
7, and the internal connection surfaces 14a of the lead terminals 13 are embraced in the
cavity S1. In other words, the opening end 9a of the cover 9 must be electrically
connected to a part of the stage 11 such that it is electrically insulated from the lead
terminals 13. Furthermore, the opening end 9 a of the cover 9 can be arranged on the
internal area of the stage 11 positioned inwardly of its periphery except for the
prescribed regions for arranging the internal connection surfaces 14a of the lead
terminals 13, the microphone chip 5, and the companion chip 7.
In addition, the opening end 9a of the cover 9 can be brought into contact with
the interconnection leads 19 and connected to the surface 3 a of the stage 11.
Alternatively, the opening end 9a of the cover 9 can be brought into contact with the
interconnection leads 19 and electrically connected to the surface 3 a of the stage 11 via
a conductive member which is arranged between the opening end 9a of the cover 9 and
the surface 3 a of the stage 11.
The aforementioned modifications increase the overall contact area between
the cover 9 and the stage 11; hence, it is possible to establish a reliable fixation

between the cover 9 and the stage 11.
In the present embodiment, the cover 9 is fixed onto the surface 3 a of the
mold sheet 3 via the conductive bonding material 32; but this is not a restriction.
Alternatively, the cover can be fixed onto the surface 3 a of the mold sheet 3 via solder.
In this case, it is possible to fix the cover 9 onto the mold sheet 3 for mounting the
microphone chip 5 and the companion chip 7 while soldering mold sheet 3
(electrically connected to the microphone chip 5 and the companion chip 7) to the
substrate in the reflow process.
In the present embodiment, the recesses 24 are formed in the entirely lengths
of the support leads 18; however, the recesses 24 can be formed in only the prescribed
parts of the support leads 18 as long as the cover 9 does not come in contact with the
support leads 18. In other words, the recesses 24 can be formed in width directions
of the support leads 18 positioned in the openings 17a of the cutouts 17 as long as the
cover 9 is fixed onto the mold sheet 3 as described in the present embodiment.
The support leads 18 do not necessarily partially project outside of the cutouts
17. Alternatively, the support leads 18 can be entirely positioned in the cutouts 17.
The lead terminals 13 are not necessarily partially arranged inside of the cutouts 17 of
the stage 11. Alternatively, the lead terminals 13 can be entirely arranged inside of
the cutouts 17 of the stage 11.
The lead frame 33 is processed by way of half-etching. Instead, the lead
frame 33 can be processed by way of press working when the mold sheet 3 is not
necessarily reduced in thickness, and when the semiconductor device 1 can be
designed without consideration of resin burrs. That is, the lead terminals 13 can be
subjected to bending. In this case, it is possible to form other recesses (similar to the
recesses 24) which are positioned below the surface 3a of the stage 11.

The sound hole 9b allowing the cavity S1 to communicate with the external
space is not necessarily formed in the cover 9. Alternatively, the sound hole 9b can
be formed at a prescribed position of the mold sheet 3.
The lead terminals 13 and the ground terminal 21 are not necessarily exposed
on the backside 15b of the resin mold 15. The present embodiment simply requires
that they are exposed externally of the mold sheet 3 so as to establish electric
connection with the substrate (for mounting the semiconductor device 1).
Alternatively, they can be exposed externally of the side surface 4 of the mold sheet 3.
In this case, the ground terminal 21 can be formed using the interconnection lead 19.
The semiconductor device 1 does not necessarily include the companion chip
7 mounted on the surface 3 a of the stage 11. The present embodiment simply
requires that the semiconductor device 1 includes at least the microphone chip 5. In
this case, it is necessary to individually mount the companion chip 7 on the substrate
(for mounting the semiconductor device 1), wherein the semiconductor device 1 is
electrically connected to the companion chip 7 via the substrate.
The present embodiment describes the semiconductor chip 1 that has the
microphone chip 5 for detecting pressure variations; but this is not a restriction. The
present embodiment can be applied to any type of the semiconductor device having a
sensor chip incorporated in the hollow cavity S1 defined between the mold sheet 3 and
the cover 9. In other words, it can be applied to any type of the semiconductor device
in which the sound hole 9b is not formed in the mold sheet 3 and the cover 9. It is
possible to list various types of sensor chips such as acceleration sensor chips arranged
inside of the cavity S1 that is air-tightly closed and isolated from the external space.
Lastly, the present invention is not necessarily limited to the present
embodiment and variations thereof, which can be further modified in a variety of ways

within the scope of the invention as defined by the appended claims.

1. A semiconductor device comprising:
a sensor chip;
a mold sheet having a rectangular shape in a plan view and including a stage
having a conductive property, in which a plurality of cutouts is formed in a periphery
thereof, a plurality of lead terminals each having a conductive property which is
arranged inside of the plurality of cutouts and is electrically connected to the sensor
chip, and a resin mold having an insulating property which is formed to electrically
insulate the stage from the plurality of lead terminals; and
a cover having an opening and a box-like shape, which is combined with the
mold sheet so as to form a cavity therebetween,
wherein the sensor chip is mounted on a surface of the stage which forms a
single plane as a surface of the mold sheet,
wherein the plurality of lead terminals includes a plurality of connection
portions having internal connection surfaces, which are exposed in the cavity and are
electrically connected to the sensor chip, and a plurality of support leads which are
elongated from the plurality of connection portions towards the stage so that distal
ends thereof are exposed on a side surface of the mold sheet,
wherein the plurality of support leads has a plurality of recesses which are
recessed in width directions thereof and which is sealed with the mold resin, and
wherein an opening end of the cover is fixed onto the mold sheet above the
recesses of the support leads sealed with the resin mold.
2. A semiconductor device according to claim 1, wherein the stage and the lead

terminals are integrally formed using a lead frame that is produced using a thin metal
plate, wherein the recesses are formed by partially etching a surface of the thin metal
plate substantially corresponding to the surface of the stage, wherein the stage is
formed by partially etching a backside of the thin metal plate and is thus reduced in
thickness so that the lower side of the stage is sealed with the resin mold.
3. A semiconductor device according to claim 2, wherein the connection
portions are formed by partially etching the backside of the thin metal plate and are
thus reduced in thickness so that the lower sides of the connection portions are sealed
with the resin mold.
4. A semiconductor device according to claim 1, wherein the mold sheet is
integrally formed with the stage such that the mold sheet partially projects from the
lower side of the stage so as to form a ground terminal, which is electrically connected
to the sensor chip, and wherein an external connection surface of the ground terminal
is exposed externally of the resin mold that is formed to seal the lower side of the
stage.
5. A semiconductor device according to claim 1, wherein the sensor chip is a
microphone chip having a sound detector for detecting pressure variations, and
wherein a sound hole is formed to run through the cover so as to allow the cavity to
communicate with an external space.
6. A lead frame, which is produced using a thin metal plate, comprising:
a stage having a rectangular shape in a plan view for mounting a sensor chip

thereon;
a plurality of lead terminals which are electrically connected to the sensor
chip and which have a plurality of connection portions integrally connected with the
stage;
a plurality of cutouts which are formed in a periphery of the stage so as to
arrange the plurality of lead terminals and the plurality of connection portions therein;
and
a plurality of support leads which are externally elongated from the plurality
of connection portions, wherein a plurality of recesses is formed in the plurality of
support leads inside of the plurality of cutouts.
7. A lead frame according to claim 6, wherein the plurality of recesses is formed
by partially etching a surface of the thin metal plate which forms a same plane as a
surface of the stage, and wherein the stage is formed by partially etching a backside of
the thin metal plate and is thus reduced in thickness.
8. A microphone package
a microphone chip;
a mold sheet having a rectangular shape in a plan view and including a stage
having a conductive property, in which a plurality of cutouts is formed in a periphery
thereof, a plurality of lead terminals each having a conductive property which is
arranged inside of the plurality of cutouts and is electrically connected to the
microphone chip, and a resin mold having an insulating property which is formed to
electrically insulate the stage from the plurality of lead terminals; and
a cover having a box-like shape, which is combined with the mold sheet so as

to form a housing including a cavity and a sound hole,
wherein the plurality of lead terminals is arranged inside of the plurality of
cutouts and is thus electrically insulated from the stage via the resin mold,
wherein the plurality of lead terminals includes a ground terminal formed
integrally with the stage and a plurality of internal connection surfaces electrically
connected to the microphone chip,
wherein the stage and the plurality of lead terminals are sealed with the resin
mold such that the surface of the stage and the plurality of internal connection surfaces
are exposed from the mold sheet in the housing, and
wherein the cover is electrically insulated from the plurality of lead terminals
and is electrically connected to the stage.
9. A microphone package according 8, wherein the mold sheet includes a lead
frame, which is formed using a thin metal plate and which includes the stage, the
plurality of lead terminals, and a plurality of support leads which are elongated from
the plurality of lead terminals so that distal ends thereof are exposed on. a side surface
of the mold sheet, and wherein a plurality of recesses is formed in the plurality of
support leads and is sealed with the resin mold.
10. A microphone package according to claim 9, wherein a plurality of
interconnection leads is extended from a periphery of the stage so that distal ends
thereof are exposed on the side surface of the mold sheet, and wherein the plurality of
interconnection leads come in contact with the cover when the cover is mounted and
fixed onto the mold sheet.

11. A microphone package according to claim 8, wherein the mold sheet includes
a lead frame having a frame, which is formed using a thin metal plate, wherein the
plurality of lead terminals has a plurality of support leads which are extended
therefrom so as to join the frame, wherein a plurality of recesses is formed by
performing half-etching on the plurality of support leads, wherein a plurality of
interconnection leads is extended from a periphery of the stage so that distal ends
thereof are exposed on a side surface of the mold sheet, wherein the lead frame of the
mold sheet is sealed with a resin such that the plurality of recesses is sealed with the
resin mold, and wherein the mold sheet is subjected to cutting so as to cut out the
plurality of interconnection leads.

Dated this 5th day of August, 2008.

A semiconductor device is constituted of a mold sheet for mounting a sensor chip and a cover having a box-like shape, both of which are combined together so as to form a cavity therebetween. The mold sheet includes a stage having a rectangular shape in a plan view, a plurality of cutouts formed in the periphery of the stage, and a plurality of lead terminals arranged inside of the cutouts. The lead terminals include a plurality of connection portions electrically connected to the sensor chip and a plurality of support leads which are externally extended from the periphery of the
stage. The stage and the lead terminals are sealed with a mold resin, by which they
are electrically insulated from each other. The recesses of the support leads are sealed with the insulating resin mold relative to the surface of the mold sheet so as to mount the opening end of the cover.