U.S. patent application number 13/014340 was filed with the patent office on 2011-05-19 for shield case and mems microphone having it.
This patent application is currently assigned to PANASONIC CORPORATION. Invention is credited to Norio Kimura, Katsuhiro Makihata.
Application Number | 20110116661 13/014340 |
Document ID | / |
Family ID | 39183839 |
Filed Date | 2011-05-19 |
United States Patent
Application |
20110116661 |
Kind Code |
A1 |
Makihata; Katsuhiro ; et
al. |
May 19, 2011 |
SHIELD CASE AND MEMS MICROPHONE HAVING IT
Abstract
To provide a shield case and an MEMS microphone having the
shield case which can secure on a top plate the minimum distance
for adhering with a gasket in a view point of airtightness. The
shield case according to the invention is a shield case for
shielding an MEMS chip mounted on a board from the outside, which
includes a top plate and a plurality of side plates and the
thickness of each of the plurality of side plates is larger than
that of the top plate. According to this configuration, the area of
the top plate can be made larger as compared with a conventional
shield case having a uniform thickness. Thus, the area for adhering
the gasket to the top plate can be secured without changing the
position, size and range etc. of the chucking area from those of
the conventional shield case.
Inventors: |
Makihata; Katsuhiro;
(Kanagawa, JP) ; Kimura; Norio; (Kanagawa,
JP) |
Assignee: |
PANASONIC CORPORATION
Osaka
JP
|
Family ID: |
39183839 |
Appl. No.: |
13/014340 |
Filed: |
January 26, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12160663 |
Jul 11, 2008 |
7904123 |
|
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PCT/JP2007/067846 |
Sep 13, 2007 |
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13014340 |
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Current U.S.
Class: |
381/174 |
Current CPC
Class: |
H01L 2924/3025 20130101;
H04R 2499/11 20130101; H04R 31/00 20130101; H01L 2924/3025
20130101; H04R 19/005 20130101; H01L 2924/01004 20130101; H01L
2924/16152 20130101; H01L 2924/1461 20130101; H01L 2224/48091
20130101; H01L 2924/19041 20130101; H01L 2224/48091 20130101; H01L
2924/1461 20130101; H01L 2924/00 20130101; H01L 2924/00014
20130101; H01L 2924/00 20130101; H01L 2224/48227 20130101; B81B
7/0077 20130101; B81B 2201/0257 20130101; H01L 23/552 20130101;
H01L 2924/16315 20130101; H01L 2924/01078 20130101; H04R 19/016
20130101 |
Class at
Publication: |
381/174 |
International
Class: |
H04R 11/04 20060101
H04R011/04 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 15, 2006 |
JP |
2006-250915 |
Claims
1-6. (canceled)
7. A MEMS microphone, comprising: a board; a MEMS chip mounted on
the board; and a shield case formed over the mounted MEMS chip, the
shield case having atop plate and a side plate, wherein a thickness
of the side plate is larger than a thickness of the top plate, and
an end portion of the side plate is attached on a surface of the
board, said MEMS being mounted on said surface of the board.
8. The MEMS microphone according to claim 7, wherein the end
portion of the side plate has an R shaped portion disposed inside
of the shield case.
9. The MEMS microphone according to claim 7, wherein a bent portion
formed by an end portion of the top plate and the other end portion
or the side plate is formed to have a corner.
10. The MEMS microphone according to claim 8, wherein a bent
portion formed by an end portion of the top plate and the other end
portion of the side plate is formed to have a corner.
11. The MEMS microphone according to claim 7, wherein the end
portion of the side plate is attached on the surface of the board
by a solder.
12. The MEMS microphone according to claim 8, wherein a solder is
formed between the R shaped portion of the end portion of the side
plate and the board.
13. The MEMS microphone according to claim 10, wherein a solder s
formed between the R shaped portion of the other end portion of the
side plate and the board.
14. The MEMS microphone according claim 7, wherein a thickness of
the top plate is approximately 0.1 mm and a thickness of the side
plate is approximately 0.25 mm.
15. The MEMS microphone according to claim 8, wherein a thickness
of the top plate is approximately 0.1 mm and a thickness of the
side plate is approximately 0.25 mm.
16. The MEMS microphone according to claim 11, wherein a thickness
of the top plate is approximately 0.1 mm and a thickness of the
side plate is approximately 0.25 mm.
17. The MEMS microphone according to claim 7, wherein the shield
case has a Ni plating.
18. The MEMS microphone according to claim 8, wherein the shield
case has a Ni plating.
19. The MEMS microphoneaccording according to claim 11 wherein
shield case has a Ni plating.
20. The MEMS microphone according to claim 7, wherein a size of a
mounting surface of the board is 3.times.4 mm or less.
21. The MEMS microphone according to claim 8, wherein a size of a
mounting surface of the board is 3.times.4 mm or less.
22. The MEMS microphone according claim 11, wherein a size of a
mounting surface of the board is 3.times.4 mm or less.
23. The MEMS microphone according to claim 12, wherein the top
plate has a sound hole and a distance from the sound hole to an end
portion of the top plate is 1 mm or more.
24. The MEATS microphone according to claim 7, wherein the top
plate and the side plate are single-piece and the top plate and the
side plate comprise metal.
25. The MEMS microphone according to claim 8, wherein the top plate
and the side plate are single-piece and the top plate and the side
plate comprise metal.
26. The MEMS microphone according to claim 11, wherein the top
plate and the side plate are single-piece and the top plate and the
side plate comprise metal.
Description
TECHNICAL FIELD
[0001] The present invention relates to a shield case that covers
an MEMS chip using the micro-machining technique utilizing the
semiconductor technique. Further, the invention relates to an MEMS
microphone and, more in detail, relates to an MEMS microphone
having a shield case.
BACKGROUND ART
[0002] Conventionally, a shield case has been employed in order to
protect electronic parts such as chips mounted on a board from
electromagnetic wave noise or dust etc. from the outside.
[0003] FIG. 6 shows a perspective outside view of a conventional
MEMS microphone. FIG. 7(a) is a side view of the conventional MEMS
microphone. FIG. 7(b) is a plan view of the conventional MEMS
microphone. FIG. 7(c) is a longitudinal sectional diagram (a
sectional diagram along a line A-A in FIG. 6) of the conventional
MEMS microphone.
[0004] The conventional MEMS microphone 300 shown in FIGS. 6 and 7
is configured by a board 301, an MEMS chip 200 and a shield case
303. The MEMS chip 200 is a chip for converting a sound signal into
an electric signal.
[0005] Such an MEMS microphone 300 is used in a state of being
mounted on the main board of a mobile phone etc. In this case, in
order to secure a passing path of the sound signal, the sound hole
for the microphone of the casing in the mobile phone and a sound
hole 303c on the top plate 303a of the shield case are disposed and
mounted in an overlapped manner. However, even if the sound holes
are disposed at an almost overlapping position, when there is a
space between the casing and the shield case 303, the sound signal
leaks from the space and so there arises a case that the acoustic
characteristics designed in advance changes.
[0006] Thus, an improvement has been made that a gasket made of
material such as rubber of silicon is adhered and sandwiched
between the top plate 303a of the shield case and the casing of the
mobile phone thereby to eliminate the space.
[0007] Further, similarly in a view point of the airtightness, a
patent document 1 describes an example in which a gasket is pasted
between a transparent panel plate and an external cover in the
mechanism of the display portion of a mobile phone (see the patent
document 1, for example).
[0008] Patent Document 1: JP-A-2005354377
DISCLOSURE OF THE INVENTION
[0009] <Problems that the Invention is to Solve>
[0010] In the case of employing the aforesaid method of filling the
space by the gasket, in order to secure the airtightness, it is at
least required to secure an area for adhering the gasket to the top
plate 303a on the top plate 303a of the shield case. In other
words, as shown in FIG. 7(b), minimum distances are at least
required as distances L1, L2 between the sound hole 303c of the
shield case and the end portions of the top plate 303a.
[0011] On the other hand, in the case of mounting the MEMS
microphone 300 on the main board of a mobile phone etc., it is
required to secure on the top plate 303a a chucking area S for
picking up and placing the MEMS microphone 300. As shown in FIG.
7(b), the chucking area S is required to avoid the sound hole 303c
on the top plate 303a of the shield case and have a constant area
in order to prevent the failure of the MEMS chip 200. Further, in
order to transport the MEMS microphone 300 stably, it is desirable
to dispose the chucking area S near the center of gravity of the
shield case as close as possible, that is, near the center of the
top plate 303a.
[0012] In addition to the aforesaid circumstances, in recent years,
the MEMS microphone 300 has been required to be further reduced in
its size and thickness, and accordingly the shield case 303 has
been reduced in its size and thickness. Accordingly, the area of
the top plate 303a of the shield case has also been reduced, and
hence it becomes difficult to secure the area for adhering the
gasket while securing the area and location etc. for the chucking
area S on the top plate.
[0013] To be concrete, the board 301 of the MEMS microphone is
planed to have a size of 3 mm in the longitudinal direction and 4
mm in the transverse direction. When this size is employed, as the
chucking area S, an area of at least 1.2 mm or more in each of the
longitudinal and transverse directions is required to be secured in
view of the weight of the shield case and the performance of a
chucking device. Further, as shown in FIG. 7(b), the chucking area
S is required to be disposed near the center of the top plate 303a
of the shield case as close as possible.
[0014] Further, in order to secure the airtightness due to the
sandwiching of the gasket, each of the distances L1, L2 from the
sound hole 303c of the shield case to the end portions of the top
plate 303a is required to be at least 1 mm or more. This distance
is desirably as long as possible in a view point of the
airtightness.
[0015] In this manner, when the area of the top plate is reduced in
the case of miniaturizing the conventional shield case, it has
become difficult to secure the distances from the sound hole 206 of
the shield case to the end portions of the top plate 303a while
securing the area and location for the chucking area S.
[0016] Further, in addition to the progress of the miniaturization,
the uniform thinning of the shield case 303 has also been
progressed within a range where the intensity of the shield case
can be secured as a structure. As an example of the current
thinnest shield case, there is one in which the thickness of each
of the plate 303 and a side plate 303b is 0.1 mm. The shield case
thus thinned is light-weighted and can secure a large size in each
of the height, width etc. of an inner frame. However, since the end
portions of the side plate are made small, the shield case is
configured in a shape soldered hardly. Thus, when the end portions
are merely fixed by the solder, the adhesive strength between the
end portions and the board is weak. Thus, as shown in FIG. 7(c), in
the conventional uniformly thinned shield case, a bent portion 303d
is provided at the end portions of the side plates 303b thereby to
provide a space where a suitable amount of the solder is collected.
A solder filet 303e is formed at a space formed by the bent portion
303d thereby to obtain the fixing intensity of the shield case.
[0017] However, the shield case 303 thinned uniformly in the
aforesaid manner is required to have a size housed within the board
301 together with the bent portion 303d, and hence the size of the
top plate 303a is made small by a size of the bent portion
303d.
[0018] Further, since the conventional shield case is usually
formed by the squeezing processing and so a bent portion 303f
formed by the end portion of the plate 303 and the side plate 303b
is configured to have an R-shaped portion (round corner). Thus, the
conventional shield case does not have a shape that can secure the
area of the flat portion of the top plate to the maximum.
[0019] The invention has been made in view of the aforesaid
problems and an object of the invention is to provide a shield case
and an MEMS microphone having the shield case which can secure on a
top plate the minimum distance for adhering with a gasket in a view
point of airtightness without changing the position, size, range
etc. of a chucking area on the top plate of a shield case, that is,
while securing the area and position of the chucking area.
<Means for Solving the Problems>
[0020] The shield case according to the invention is a shield case
for shielding an MEMS chip mounted on a board from outside, which
includes a top plate and a plurality of side plates, wherein the
thickness of each of the plurality of side plates is larger than
the thickness of the top plate.
[0021] According to this configuration, the area of the top plate
can be enlarged as compared with the conventional shield case
having a uniform thickness. Thus, the area for adhering the gasket
to the top plate can be secured without changing the position, size
and range etc. of a chucking area from the conventional shield
case.
[0022] Further, the shield case according to the invention is
arranged in a manner that a bent portion formed by the end portion
of the top plate and the side plate is formed to have a corner.
[0023] According to this configuration, the area of the flat
portion of the top plate can be enlarged. The shield case according
to the invention can be formed to have a corner portion by the
hammering processing performed within a pressing mold, for example.
The bent portion formed by the end portion of the top plate and the
side plate can be formed to have an R of 0.05 or less, whereby the
area of the flat portion of the top plate can be enlarged
sufficiently and so the adhering property with the gasket can also
be improved.
[0024] Further, the shield case according to the invention is
arranged in a manner that each of end portions of the plurality of
side plates has an R shaped portion toward the inside of the shield
case.
[0025] According to this configuration, in the case of mounting the
shield case by the reflow soldering processing, since solder enters
into the space of the R-shaped portion to form a solder filet, the
shield case can be firmly fixed to the board etc. with a suitable
amount of the solder. The R-shaped portion desirably has an R of
0.1 or less, and so the space formed by the R-shaped portion can
hold a sufficient amount of the solder.
[0026] The MEMS microphone according to the invention is arranged
to include a board; an MEMS chip mounted on the board; and a shield
case, for shielding the MEMS chip from outside, which includes a
top plate and a plurality of side plates, wherein the thickness of
each of the plurality of side plates is larger than the thickness
of the top plate.
[0027] According to this configuration, the area of the top plate
of the shield case can be enlarged as compared with the
conventional shield case having a uniform thickness. Thus, the
distance for adhering the gasket to the top plate can be secured to
be long without changing the position, size and range etc. of the
chucking area from the conventional shield case.
[0028] Further, the MEMS microphone according to the invention is
arranged in a manner that a bent portion formed by the end portion
of the top plate and the side plate of the shield case is formed to
have a corner.
[0029] According to this configuration, the area of the flat
portion of the top plate of the shield case covering the MEMS chip
can be enlarged.
[0030] Further, the MEMS microphone according to the invention is
arranged in a manner that each of the end portions of the plurality
of side plates has an R shaped portion toward inside of the shield
case.
[0031] According to this configuration, in the case of mounting the
shield case by the reflow soldering processing etc., since solder
enters into the space of the R-shaped portion to form a solder
filet, the shield case can be firmly fixed to the board with a
suitable amount of the solder.
<Effects of the Invention>
[0032] According to the invention, since the area of the top plate
can be enlarged, the area for adhering the gasket to the top plate
can be secured without changing the position, size and range etc.
of the chucking area from the conventional shield case.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 is a perspective outside view of an MEMS microphone
100 according to the first embodiment.
[0034] FIG. 2 is a longitudinal sectional view (a sectional diagram
along a line B-B of FIG. 1) of the MEMS microphone 100.
[0035] FIG. 3 (a) is a side view of the MEMS microphone 100, (b) is
a plan view of the MEMS microphone 100, (c) is a sectional view
along a line C-C in FIG. 3(b), and (d) is a sectional view along a
line D-D in FIG. 3(b).
[0036] FIG. 4 is a perspective outside view of a mobile phone 150
in which the MEMS microphone 100 is mounted.
[0037] FIG. 5 is a sectional view of a main portion (sectional view
along a line E-E in FIG. 4) near the microphone portion of the
mobile phone 150.
[0038] FIG. 6 is a perspective outside view of a conventional MEMS
microphone.
[0039] FIG. 7 (a) is a side view of the conventional MEMS
microphone, (b) is a plan view of the conventional MEMS microphone,
and (c) is a longitudinal sectional diagram (a sectional diagram
along a line A-A in FIG. 6) of the conventional MEMS
microphone.
EXPLANATION OF SIGNS
[0040] 100 MEMS microphone [0041] 101 board [0042] 102 MEMS chip
[0043] 103 shield case [0044] 103a top plate [0045] 103b side plate
[0046] 103c sound hole [0047] 103d R-shaped portion [0048] 103e
solder filet [0049] 103f bent portion [0050] 150 mobile phone
[0051] 151 casing [0052] 152 sound hole on casing [0053] 154 gasket
[0054] 155 main board of mobile phone
BEST MODE FOR CARRYING OUT THE INVENTION
First Embodiment
[0055] FIG. 1 shows a perspective outside view of an MEMS
microphone 100 according to the first embodiment. FIG. 2 shows a
longitudinal sectional view (a sectional diagram along a line B-B
of FIG. 1) of the MEMS microphone 100. As shown in FIGS. 1 and 2,
the MEMS microphone 100 includes a board 101, an MEMS chip 102 and
a shield case 103 and is characterized in that the thickness of
each of a plurality of side plates 103b constituting the shield
case 103 is larger than that of a top plate 103a.
[0056] The board 101 is a printed board for mounting the MEMS chip
102 thereon. The size of the mounting surface of the board 101 is 3
mm in the longitudinal direction and 4 mm in the transverse
direction, for example.
[0057] As shown in FIG. 2, the MEMS chip 102 converts a sound
signal obtained from a vibration film electrode 43 into an electric
signal. To be concrete, the MEMS chip 102 includes the vibration
film electrode 43 and an electret film 44 via a first insulation
layer 42 on the silicon board 41 and further includes a fixed
electrode 46 provided with a sound hole 47 via a second insulation
layer 45 on the first insulation layer. Further, a back air chamber
55 is formed on the rear surface of the vibration film electrode 43
by etching the silicon board 41. MEMS (Micro Electro Mechanical
System) means an electromechanical system configured by fine parts
which are fabricated by using the micro fabrication technique for a
semiconductor.
[0058] The vibration film electrode 43 is formed by conductive
polysilicon. The electret film 44 is formed by a silicon nitride
film or a silicon oxide film. By laminating conductive polysilicon
and a silicon oxide film or a silicon nitride film, the fixed
electrode 46 is formed.
[0059] An amplifying circuit 48 for amplifying the electric signal
from the MEMS chip 102 is electrically coupled by a wire. The MEMS
chip 102 and the amplifying circuit 48 are covered by the shield
case 103.
[0060] Next, the explanation will be made as to the shield case
103. FIG. 3(a) is a side view of the MEMS microphone 100. FIG. 3(b)
is a plan view of the MEMS microphone 100. FIG. 3(c) is a sectional
view along a line C-C in FIG. 3(b). FIG. 3(d) is a sectional view
along a line D-D in FIG. 3(b). In each diagram of FIG. 3, the MEMS
chip 102 is not shown.
[0061] As shown in each diagram, the shield case 103 is configured
by a top plate 103a of an almost rectangular shape having four
round corners and four side plates 103b. The material of the shield
case is metal having the electric shield property such as nickel
silver (alloy formed by copper, lead and nickel), kovar or 42
alloy. The shield case may be subjected to the surface processing
such as Ni plating in order to join with a board by the soldering
etc. The thickness of the top plate 103a is 0.1 mm and the
thickness of each of the side plates 103b is 0.25 mm. The shield
case 103 has a different thickened structure in which the side
plate 103b has a larger thickness than the top plate 103a. Further,
the end portion 103f of the top plate 103a is formed to have a
corner portion. The shield case 103 can be configured in a shape
having corner portions by the hammering processing performed within
a pressing mold, for example. The corner of the end portion 103f of
the top plate 103a according to the invention is formed to have an
R of 0.05 or less. On the other hand, the corner of the end portion
according to the conventional squeezing processing is formed to
have an R of 0.2 or less. The shape of the corner may have the R
smaller (radius of a circle is smaller) than that of the shape of
the corner of the bent portion formed by the conventional squeezing
processing.
[0062] According to this configuration, since the bent portion
formed by the end portion of the top plate and the side plate is
not formed to have a relatively large R like the conventional
shield case but formed to have a corner, that is, a small R, the
flat portion of the top plate is enlarged by an amount
corresponding to the thickness of the side plate. Further, the area
of the top plate is enlarged by an amount corresponding to the
enlarged thickness of the side plate. Thus, in the design of the
top plate of the shield case, the area to be adhered to the gasket
can be secured and also the chucking area can be secured.
[0063] That is, for example, the top plate 103a of the shield case
according to the first embodiment includes the sound hole 103c
having a diameter of 0.6 mm. In the top plate 103a of the shield
case, the chucking area S is secured at the position not
overlapping with the sound hole 103c. The chucking area S is set to
have a size of 1.2 mm in each of the longitudinal and transverse
directions and is disposed in a manner that the center portion
thereof locates near the center portion of the top plate 103a of
the shield case. Since the corner is formed at each of the end
portions of the top plate and the side plate is configured in the
different thickened structure thereby to enlarge the area of the
flat portion of the top plate 303a, it becomes possible to dispose
the sound hole 103c at the position not overlapping with the
chucking area S and further at such a position that the distances
L1, L2 from the sound hole 103c to the end portions of the top
plate 103a are 1 mm or more. Since the shield case is formed in a
manner that a single plate is processed so as to have different
thicknesses, then the plate is subjected to the forming processing
within the pressing mold and subjected to the hammering processing
within the pressing mold, the side plate is formed to have a larger
thickness than the top plate and have the small R. Further, the
side plates 103b of the shield case are formed at the end portions
of the respective sides o f the top plate 103a of the rectangular
shape, respectively. The shield case 103 is formed by the top plate
103a and the four side plates 103b and is configured in a lid shape
of an almost rectangular shape. The end portion of the side plate
103b is processed so as to have an R-shaped portion 103d toward the
inside of the shield case 103.
[0064] According to the aforesaid configuration, in the case of
mounting the shield case 103 on the board 101 by the reflow
soldering processing etc., since the solder enters into the space
of the R-shaped portion 103d to form a solder filet 103e as shown
in FIG. 2, the shield case can be firmly fixed to the board with a
suitable amount of the solder. Conventionally, since the R-shaped
portion has an R of about 0.15, the space of the R-shaped portion
103d can not hold a sufficient amount of the solder. However, since
the R-shaped portion of the embodiment has an R of 0.1 or less, the
space of the R-shaped portion 103d can hold a sufficient amount of
the solder.
[0065] Although the first embodiment is explained as to the case
where the shield case is configured in the rectangular lid shape,
the shape of the shield case is not limited thereto and may be
modified in accordance with the shape of the board. For example,
when the board 101 has a circular shape, the top plate of the
shield case 103 also may be configured in a circular shape.
Further, when the board 101 has a polygonal shape, the top plate of
the shield case 103 also may be configured in a polygonal
shape.
Second Embodiment
[0066] Next, the explanation will be made as to a case where the
MEMS microphone 100 is used for a mobile phone. FIG. 4 is a
perspective outside view of a mobile phone 150 in which the MEMS
microphone 100 is mounted. FIG. 5 is a sectional view of a main
portion (sectional view along a line E-E in FIG. 4) near the
microphone portion of the mobile phone 150.
[0067] In the casing 151 of the mobile phone 150 shown in FIG. 4, a
sound hole 152 for the microphone is formed at a position
corresponding to near the mouth of a user in use.
[0068] A gasket 154 is sandwiched between the top plate 103a of the
shield case of the MEMS microphone 100 and the inner side surface
of the casing 151. Like the shield case of the first embodiment,
this shield case 103 is also characterized in that the thickness of
the side plate 103b is larger than that of the top plate 103a. As
shown in FIG. 5, the sound hole 152 of the casing 151 has almost
the same shape as the sound hole 103c of the shield case, and these
sound holes are formed so as to be overlapped to each other after
the assembling.
[0069] The gasket 154 is also provided with a hole 154a having
almost the same shape as the sound hole 103c. An acoustic
resistance material 154b is formed at the end portion on the casing
side of the hole 154a. The acoustic resistance material 154b serves
to reduce the propagation speed of the sound signal and in this
case acts to adjust the acoustic characteristics of the MEMS
microphone 100.
[0070] The thickness of the gasket 154 is slightly larger than the
space between the top plate 103a and the inner side surface of the
casing 151, and so the gasket is sandwiched in a closely adhered
state from the sound hole 103c to each of the end portions of the
top plate 103a of the shield case.
[0071] That is, as the area for sandwiching the gasket 154, the
distances L1, L2 from the sound hole 103c to the respective end
portions of the top plate 103a of the shield case are designed to
be 1 mm or more, the airtightness after sandwiching the gasket 154
can be secured.
[0072] Accordingly, since the sound signal entering from the sound
hole 152 of the casing does not leak into the space between the top
plate 103a and the inner side surface of the casing 151, the
acoustic characteristics of the MEMS microphone 100 can not be
degraded.
[0073] Sound entered from the sound hole 152 of the casing passes
the acoustic resistance material 154b and propagated to the
vibration film electrode 43 of the MEMS chip. Thus, the
electrostatic capacity of a plate capacitor configured by the
vibration film electrode 43 and the fixed electrode 46 changes and
so the sound is taken out as a voltage change between the vibration
film electrode 43 and the fixed electrode 46.
[0074] The MEMS microphone 100 is enlarged in the area of the top
plate by employing the different thickened structure at the shield
case 103, whereby the problem of the sound leak at the gasket can
be solved. Thus, the miniaturized MEMS microphone 100 can be
mounted on a mobile phone, which contributes to the miniaturization
and thinning of the entire shape of the mobile phone 150.
[0075] Further, since the shield case 103 has the different
thickened structure in which the thickness of the side plate has a
larger thickness than the top plate, the position of the center of
the gravity is stable as compared with a shield case having a
uniform thickened structure. Thus, in the assembling process, when
a chucking device chucks the chucking area S of the shield case 103
and transports the MEMS microphone 100, the microphone can be
transported stably. In other words, a process of transporting the
MEMS microphone 100 to the mounting position of the main board 155
of the mobile phone 150 can be performed surely and stably.
INDUSTRIAL APPLICABILITY
[0076] According to the invention, since the area of the top plate
of the shield case can be enlarged, the invention is useful as the
shield case and the MEMS microphone having the shield case which
can secure the area for adhering the gasket to the top plate
without changing the position, size and range etc. of the chucking
area from the conventional ones.
* * * * *