JP2010258719

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DESCRIPTION JP2010258719
An acoustic transducer unit capable of efficiently performing wire bonding without restriction is
provided. SOLUTION: The first member 30 is formed with (a) an opening 39 and a hollow portion
38 communicating with the opening 39; (b) it is joined to the first member 30 and covers the
opening 39 of the first member 30 The second member 20 and (c) an acoustic conversion
element 2 disposed in the hollow portion 38 of the first member 30 and converting sound into
an electric signal or converting the electric signal into sound. The terminal electrode 52 formed
on the surface 31 surrounding the periphery of the opening 39 of the first member 30 and the
electrode pad 6 formed on the upper surface 2 a of the acoustic conversion element 2 are
electrically joined via the wire 8 There is. The difference between the height of the surface 31
surrounding the periphery of the opening 39 of the first member 30 and the height of the upper
surface 2 a on which the electrode pad 6 of the acoustic conversion element 2 is formed is small.
[Selected figure] Figure 1
Acoustic transducer unit
[0001]
The present invention relates to an acoustic transducer unit, and more particularly to an acoustic
transducer unit in which acoustic conversion elements such as microphones and speakers are
housed in a housing.
[0002]
Heretofore, various configurations of acoustic transducer units have been proposed.
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[0003]
For example, in the microphone package 101 shown in the cross-sectional views of FIGS. 6 and 7,
the microphone chip 105 and the LSI chip 107 are mounted on the bottom surface 113 a of the
recess 113 formed in the ceramic multilayer substrate 103. A lid member 131 is bonded to the
upper surface 103 a of the multilayer substrate 103.
As shown in FIG. 6, the electrode pad 105b formed on the upper surface 105a of the microphone
chip 105 and the electrode pad 107b formed on the upper surface 107a of the LSI chip 107 are
electrically connected by the first wire 137. There is.
Further, as shown in FIG. 7, the other electrode pad 107 c formed on the upper surface 107 a of
the LSI chip 107 is electrically connected to the internal terminal 119 using the second wire 139.
The internal terminal 119 is formed on the upper surface 115 a of the step portion 115 provided
in the recess 113. By making the height position of the upper surface 115 a of the step portion
115 substantially the same as the height position of the upper surface 107 a of the LSI chip 107,
wire bonding can be easily performed (see, for example, Patent Document 1).
[0004]
JP 2008-66983 A
[0005]
In the configuration of FIG. 7, the upper surface 103a of the ceramic multilayer substrate 103 in
which the recess 113 is formed is located higher than the upper surface 115a of the stepped
portion 115 in which the internal terminal 119 to be wire bonded is formed. In the vicinity of the
terminal 119, a side wall portion forming the concave portion 113 of the ceramic multilayer
substrate 103 protrudes.
This sidewall portion can be an obstacle during the operation of the wire bonding process. As a
result, the selection range of mechanical equipment, tools, etc. used in the wire bonding process
is limited, and there is a problem of reducing the workability.
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[0006]
In view of such circumstances, the present invention seeks to provide an acoustic transducer unit
capable of performing wire bonding efficiently without restriction.
[0007]
The present invention provides an acoustic transducer unit configured as follows to solve the
above problems.
[0008]
The acoustic transducer unit comprises: (a) a first member formed with an opening and a cavity
communicating with the opening; (b) a first member joined to the first member and covering the
opening in the first member; And (c) an acoustic transducer element disposed in the cavity of the
first member for converting an acoustic signal into an electrical signal or an electrical signal into
an acoustic signal.
At least one of the first member and the second member is formed with an acoustic path that
communicates the hollow portion of the first member with the external space.
The depth of the hollow portion of the first member and the height of the acoustic conversion
element are substantially equal. A terminal electrode is formed on a surface surrounding the
periphery of the opening of the first member. When the acoustic conversion element is disposed
in the hollow portion of the first member, an electrode pad is formed on a surface extending in
the vicinity of the opening of the first member. The terminal electrode of the first member and
the electrode pad of the acoustic conversion element are electrically joined via a wire. The
difference between the height of the surface surrounding the periphery of the opening of the first
member and the height of the surface on which the electrode pad of the acoustic conversion
element is formed is small.
[0009]
According to the above configuration, the depth of the hollow portion of the first member and
the height of the acoustic conversion element are substantially equal, and the height of the
surface surrounding the periphery of the opening of the first member and the surface on which
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the electrode pad of the acoustic conversion element is formed The difference with the height is
small. As described above, when the surface on which the electrode pad of the acoustic
conversion element is formed and the surface surrounding the opening of the first member have
the same height, or if one is smaller than the other in dimension, the wire bonding The wire
bonding can be efficiently performed without interference or the like which is restricted during
the operation.
[0010]
Preferably, in the second member, a recess into which the wire is inserted is formed in at least a
portion of the main surface facing the first member facing the wire and in the vicinity thereof.
[0011]
In this case, the recess formed in the second member can prevent the wire connecting the
terminal electrode of the first member and the electrode pad of the acoustic conversion element
from interfering with the second member.
[0012]
Preferably, the second member has a peripheral wall portion protruding toward the first member
on the periphery of the main surface facing the first member.
[0013]
In this case, the second member can be formed with a recess to avoid interference with the wire
with a simple configuration.
Further, the peripheral wall portion of the second member is configured to be engaged or fitted
with the first member, so that alignment and assembly of the first member and the second
member can be easily performed.
[0014]
The acoustic transducer unit of the present invention can perform wire bonding efficiently
without restriction.
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[0015]
(A) Partial cross section disassembled perspective view of acoustic transducer unit, (b) It is an
assembly sectional view.
(Example 1) (a) A partial cross-sectional exploded perspective view of an acoustic transducer
unit, (b) a perspective view of a second member, and (c) an exploded cross-sectional view of an
acoustic transducer unit.
(Example 2) (a) An exploded perspective view of an acoustic transducer unit, (b) It is an assembly
sectional view.
(Example 2) (a) is a perspective view of an acoustic transducer unit, (b) is a sectional view, and (c)
is a sectional view. (Example 3) (a) is a perspective view of an acoustic transducer unit, (b) is a
sectional view, and (b) is a sectional view. (Example 4) It is sectional drawing of an acoustic
transducer unit. (Prior Art) FIG. 6 is a cross-sectional view of an acoustic transducer unit.
(Conventional example)
[0016]
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to
5.
[0017]
Example 1 An acoustic transducer unit 10 of Example 1 will be described with reference to FIG.
[0018]
FIG. 1A is a partial cross-sectional exploded perspective view of the acoustic transducer unit 10.
FIG. 1 (b) is an assembled cross-sectional view taken along line A-A of FIG. 1 (a).
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As shown in FIG. 1, in the acoustic transducer unit 10, a microphone element 2 which is an
acoustic conversion element is accommodated in a housing which is generally constituted by a
first member 30 and a second member 20.
[0019]
The first member 30 is a member in which the cylindrical portion 32 and the bottom portion 34
are combined, and the concave portion 38 is formed by the cylindrical portion 32 and the bottom
portion 34. The recess 38 is a cavity communicating with the opening 39 formed in the upper
surface 31 a of the first member 30. The upper surface 31 a of the first member 30 is a surface
surrounding the periphery of the opening 39 of the first member 30. The first member 30 is
integrally formed with the terminal member 50 by insert molding, for example, using a resin
material.
[0020]
The terminal member 50 includes a terminal electrode 52 extending along the upper surface 31
a of the first member 30, an external terminal 56 extending along the lower surface 31 b of the
first member 30, and a side surface 31 c of the first member 30. And an intermediate portion 54
extending between the terminal electrode 52 and the external terminal 56. The terminal member
50 is formed of a conductive material such as metal, for example, copper.
[0021]
The microphone element 2 is a module component including an acoustic conversion element unit
(sensor unit) 4 that converts sound into an electric signal and a peripheral circuit, and is, for
example, a MEMS microphone. Instead of the microphone element 2, an acoustic conversion
element, such as a speaker element, which converts an electric signal to sound may be used.
[0022]
The microphone element 2 is mounted on the bottom 34 of the first member 30. For example,
the lower surface 2b is fixed to the bottom 35 of the bottom 34 by an adhesive (not shown). An
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electrode pad 6 is formed on the top surface 2 a of the microphone element 2. The electrode pad
6 formed on the upper surface 2 a of the microphone element 2 and the terminal electrode 52
formed on the upper surface 31 a of the first member 30 are electrically connected to each other
through the wire 8. The external terminal 56 of the terminal member 50 is electrically connected
to an external circuit (not shown) when the acoustic transducer unit 10 is mounted on the
external circuit (not shown).
[0023]
The height of the microphone element 2 is substantially equal to the depth of the recess 38 of
the first member 30. The difference between the height of the top surface 2 a of the microphone
element 2 and the height of the top surface 31 a of the first member 30 is small. That is, when
wire bonding between the electrode pad 6 formed on the upper surface 2 a of the microphone
element 2 and the terminal electrode 52 formed on the upper surface 31 of the first member 30,
flexibility in process design such as selection of mechanical equipment and tools Is small enough
not to cause interference or the like. For example, the height difference is preferably 0.6 mm or
less, and more preferably 0.4 mm or less. Therefore, wire bonding can be efficiently performed
between the electrode pad 6 formed on the upper surface 2 a of the microphone element 2 and
the terminal electrode 52 formed on the upper surface 31 of the first member 30 without being
restricted.
[0024]
The second member 20 is a member in which the plate-like main body 21 and the peripheral
wall 23 are joined, and the main body 21 and the peripheral wall 23 form a recess 22. The
peripheral wall portion 23 is formed on the peripheral edge of the main surface 21 s facing the
first member 30 of the main body portion 21 so as to protrude toward the first member 30 side.
The second member 20 is formed using, for example, a resin.
[0025]
As shown in FIG. 1B, the second member 20 adheres to the end surface 23s of the peripheral
wall portion 23 of the lower surfaces 23s and 21s so as to cover the opening 39 formed in the
upper surface 31 of the first member 30. It joins to the upper surface 31a of the 1st member 30
by an agent, thermocompression bonding, heat sealing etc. Thus, the microphone element 2 is
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sealed in the internal space 40 formed by the recess 38 of the first member 30 and the second
member 20. At this time, the wire 8 enters the recess 22 of the second member 20.
[0026]
A through hole 36 is formed in the bottom portion 34 of the first member 30 as an acoustic path
that communicates the recess 38 in which the microphone element 2 is disposed with the
external space.
[0027]
The acoustic path connecting the internal space 40 in which the microphone element 2 is
disposed to the external space may be formed in the second member 20 or in both the first
member 30 and the second member 20. .
Further, even if the internal space 40 is formed to extend from the internal space 40 to the
external space through the first member 30 and the second member 20, the internal space 40 is
formed to extend to the external space through the second member 20 and the first member 30.
You may Moreover, even if it forms multiple, you may form so that it may merge or branch.
[0028]
If there is a difference in height between the two pads 105b and 107b to be bonded as in FIG. 6
described above, recognition failure due to focusing failure or the like tends to occur in the wire
bonding apparatus. In addition, it takes time to focus and recognize an image per mounted chip,
and when the number of mounted chips increases, the time can not be ignored, which affects
productivity. In addition, it is difficult to wire-bond in the vicinity of the chip, and a wire wiring
space is required, so the size can not be reduced. Furthermore, an unnecessary volume is
required, which makes it difficult to optimize the microphone characteristics.
[0029]
On the other hand, in the acoustic transducer unit 10 of the first embodiment, since the
difference in height between the wire bonding pads 6 and 52 is small, the above problem can be
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avoided. At the same time, wire bonding can be performed in the vicinity of the microphone
element 2 even by using a normal wire bonding tool or a wire bonding method, and the wire can
be shortened. Therefore, parasitic capacitance is reduced and the S / N ratio is improved. An
acoustic transducer unit can be provided.
[0030]
In addition, accurate bonding of the position can be achieved, and the yield rate can be improved,
the element can be miniaturized, and an inexpensive acoustic transducer unit can be provided.
[0031]
Second Embodiment An acoustic transducer unit 10a according to a second embodiment will be
described with reference to FIG.
[0032]
The acoustic transducer unit 10a of the second embodiment is configured substantially the same
as the acoustic transducer unit 10 of the first embodiment.
Below, the same code ¦ symbol is used for the same component as Example 1, and it
demonstrates focusing on difference with Example 1. FIG.
[0033]
FIG. 2A is an exploded perspective view of a partial cross section of the acoustic transducer unit
10a.
FIG.2 (b) is a perspective view of the 2nd member 20a seen along line B-B of FIG. 2 (a). FIG.2 (c)
is a disassembled sectional view cut ¦ disconnected along line CC of FIG. 2 (a).
[0034]
As shown in FIG. 2, in the acoustic transducer unit 10 a of the second embodiment, the second
member 20 a is fitted to the first member 30.
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[0035]
That is, as in the first embodiment, the second member 20a is a member in which the plate-like
main body portion 21a and the peripheral wall portion 23a are combined.
However, unlike the first embodiment, as shown in FIG. 2C, the second member 20a is formed so
as to expand outward from the first member 30, and the peripheral wall 23a is a side surface 31c
of the first member 30. It is supposed to fit outside.
[0036]
Further, as shown in FIG. 2B, in the second member 20a, a projection 24 whose height is lower
than that of the peripheral wall 23a is formed on the main surface 21t of the main body 21a
facing the first member 30. There is. When the second member 20a is fitted to the first member
30, the distal end surface 24s of the projection 24 abuts on the upper surface 31a of the first
member 30 to restrict the height of the main surface 21t, as shown in FIG. As shown in c), the
main surface 21t opposite to the first member 30 of the main body 21a is prevented from
interfering with the wire 8.
[0037]
In addition, in FIG. 2, illustration is abbreviate ¦ omitted about parts other than terminal electrode
52a about a terminal member. Moreover, illustration of the acoustic path which connects
between the recessed part 38 of the 1st member 30 and external space is abbreviate ¦ omitted.
[0038]
Since the difference between the height of the upper surface 2a of the microphone element 2 on
which the electrode pad 6 is formed and the height of the upper surface 31a of the first member
30 is small, the acoustic transducer unit 10a of the second embodiment is the same as the first
embodiment. Wire bonding can be efficiently performed without any restriction. Further, by
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configuring the second member 20a to be fitted to the first member 30, the alignment and
assembly of the first member 30 and the second member 20a can be facilitated.
[0039]
Third Embodiment An acoustic transducer unit 10b according to a third embodiment will be
described with reference to FIG.
[0040]
FIG. 3 (a) is an exploded perspective view of the acoustic transducer unit 10b.
FIG.3 (b) is an assembly sectional view cut ¦ disconnected along line B-B of FIG. 3 (a). As shown in
FIG. 3, the acoustic transducer unit 10 b of the third embodiment is configured substantially the
same as the acoustic transducer unit 10 of the first embodiment.
[0041]
However, unlike the first embodiment, the second member 20 b includes the plate member 26 in
which the through hole 27 is formed, and the sealing layer 28 joined to the upper surface 26 a of
the plate member 26 and closing the through hole 27. . The through hole 27 formed in the plate
member 26 functions as a recess into which the wire 8 is inserted when the second member 20b
is joined to the first member 30, as shown in FIG. 3 (b).
[0042]
The through hole 27 can be formed at low cost, for example, by subjecting a flat plate-like
member to be the plate member 26 to a simple additional processing. The sealing layer 28 can
be easily formed by attaching a film material or the like to the plate member 26.
[0043]
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The acoustic transducer unit 10b of Example 3 reduces the difference between the height of the
upper surface 2a of the microphone element 2 on which the electrode pad 6 is formed and the
height of the upper surface 31a of the first member 30 to obtain the acoustic transducer unit
10b. Similarly, wire bonding can be performed efficiently without restriction. In addition, since
the second member 20b has a simple shape and is easy to manufacture, the manufacturing cost
can be reduced.
[0044]
Example 4 An acoustic transducer unit of Example 4 will be described with reference to FIG.
[0045]
FIG. 4A is a perspective view of a first member 30c of the acoustic transducer unit according to
the fourth embodiment.
FIG.4 (b) is sectional drawing cut ¦ disconnected along line AA of Fig.4 (a). FIG. 4 (b c) is a crosssectional view taken along line A-A in FIG. 4 (a), and is a cross-sectional view of the first member
30 c when the microphone element 2 is mounted.
[0046]
As shown in FIG. 4, the first member 30 c is a member in which the cylindrical portion 32 c and
the bottom portion 34 are joined as in the first embodiment, but unlike the first embodiment, the
first member 30 c is formed of the cylindrical portion 32 c of the first member 30 c. The
protrusion 32p is formed, and a step is formed on the surface surrounding the periphery of the
opening 39c of the first member 30c. A terminal electrode 52c is formed on a tip end surface
32s of the protrusion 32p which becomes the highest among surfaces surrounding the periphery
of the opening of the first member.
[0047]
The terminal electrode 52c is electrically connected to the electrode pad 6 formed on the upper
surface 2a of the microphone element 2 mounted in the recess 38 of the first member 30c via
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the wire 8 as shown in FIG. 4C. Be done. By reducing the difference between the height of the
upper surface 2a of the microphone element 2 on which the electrode pad 6 is formed and the
height of the tip surface 32s of the protrusion 32p of the first member 30c, the same restriction
as in the first embodiment is given. Thus, wire bonding can be performed efficiently.
[0048]
Although not shown, the second member joined to the first member 30c is configured to engage
or engage with a stepped portion formed on the surface surrounding the opening 39c of the first
member 30c. For example, corresponding to the protrusion 32p of the first member 30c, a notch
is formed in the peripheral wall of the second member, and the protrusion 32p of the first
member 30c is engaged with the notch of the peripheral wall of the second member Configure to
mate. As a result, alignment and assembly of the first member 30c and the second member can
be facilitated.
[0049]
Example 5 An acoustic transducer unit of Example 5 will be described with reference to FIG.
[0050]
FIG. 5A is a perspective view of a first member 30 d of the acoustic transducer unit according to
the fifth embodiment.
FIG. 5 (b) is a cross-sectional view taken along line A-A of FIG. 5 (a). FIG.5 (c) is sectional drawing
cut ¦ disconnected along line AA of Fig.5 (a), and is sectional drawing of the 1st member 30d
when the microphone element 2 is mounted.
[0051]
As shown in FIG. 5, the first member 30 d is a member in which the cylindrical portion 32 d and
the bottom portion 34 are combined as in the first embodiment, but unlike the first embodiment,
the notch 32 q is formed in the cylindrical portion 32 d. A step is formed on the surface
surrounding the periphery of the opening 39d of the first member 30d. A terminal electrode 52d
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is formed on the bottom surface 32t of the lowest notch 32q on the surface surrounding the
opening 39 of the first member 30d.
[0052]
The terminal electrode 52d is electrically connected to the electrode pad 6 formed on the upper
surface 2a of the microphone element 2 mounted in the recess 38 of the first member 30d via
the wire 8 as shown in FIG. 5C. Be done. By reducing the difference between the height of the
upper surface 2a of the microphone element 2 on which the electrode pad 6 is formed and the
height of the bottom surface 32t of the notch 32q of the first member 30d, the notch 32q has
appropriate dimensions and shapes As in the first embodiment, wire bonding can be efficiently
performed without restriction.
[0053]
As in the second embodiment, the second member 20 d is configured to be fitted around the first
member 30 d. The first member 20d is formed with the notch 32q so that the upper surface 31t
is higher than the wire 8, so that the wire 8 does not interfere with the second member 20d.
Therefore, unlike the second embodiment, the second member 20d is not formed with a
projection that defines the depth to which the second member 20d fits into the first member
30d. Therefore, the acoustic transducer unit of the fifth embodiment can simplify the
configuration of the second member more than the acoustic transducer unit of the second
embodiment.
[0054]
<Summary> As described above, a microphone element in which a terminal electrode is formed
on the surface surrounding the periphery of the opening of the first member, and an electrode
pad electrically connected to the terminal electrode through a wire is formed. By reducing the
difference between the height of the upper surface and the height of the surface surrounding the
opening of the first member on which the terminal electrode is formed, wire bonding can be
efficiently performed without restriction.
[0055]
The present invention is not limited to the above embodiment, and can be implemented with
various modifications.
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[0056]
For example, in the first embodiment, the external terminal 56 side of the terminal member 50 is
extended and bent to the second member side, and the terminal portion for mounting the
acoustic transducer unit on the external circuit is not the bottom surface of the housing but the
top surface of the housing. It may be provided in
In this case, only by changing the bending direction of the terminal member 50 in the same
package, the direction of the acoustic path at the time of mounting can be easily changed.
[0057]
Reference Signs List 2 microphone element (acoustic conversion element) 6 electrode pad 8 wire
10, 10a, 10b acoustic transducer unit 20, 20a, 20b, 20d second member 21, 21a, 21d main body
portion 22, 22a, 22d concave portion 23, 23a, 23d Peripheral wall portion 24 Protrusion portion
26 Plate member 27 Through hole (recessed portion) 28 Sealing layer 30, 30c, 30d First
member 32, 32c, 32d Tube portion 34 Bottom portion 36 Through hole (acoustic path) 38
Recessed portion (cavity portion) 39 Opening 52, 52c, 52d terminal electrode
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