JP2007116650

Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JP2007116650
PROBLEM TO BE SOLVED: To provide a diaphragm whose internal stress is controlled with high
accuracy, a method of manufacturing the same, and a condenser microphone using the
diaphragm. A multilayer film having a first thin film and a second thin film by forming a first thin
film by deposition and forming a second thin film having a different internal stress from the first
thin film. And adjusting the internal stress of the diaphragm. [Selected figure] Figure 1
Method of manufacturing diaphragm and diaphragm, and condenser microphone
[0001]
The present invention relates to a diaphragm and a method of manufacturing the diaphragm and
a condenser microphone, and more particularly to a diaphragm used for a MEMS (Micro
Electronics Mechanical System) such as a condenser microphone and an acceleration sensor
using a semiconductor film, a manufacturing method thereof and a condenser microphone.
[0002]
Condenser microphones and acceleration sensors that can be manufactured by applying the
manufacturing process of semiconductor devices are known.
The condenser microphone has an electrode on each of the plate and the diaphragm that vibrates
by sound waves, and the plate and the diaphragm are supported apart from each other by the
insulating spacer. The condenser microphone converts a capacitance change due to the
11-05-2019
1
displacement of the diaphragm into an electrical signal and outputs it. Therefore, in the
condenser microphone, properly controlling the internal stress of the diaphragm is essential for
improving the sensitivity. For example, in the condenser microphone disclosed in Non-Patent
Document 1, when tensile stress remains in the diaphragm, the sensitivity decreases due to the
decrease in amplitude of the diaphragm, and when compressive stress remains, it is due to
deflection of the diaphragm. Desensitization occurs.
[0003]
Conventionally, when the diaphragm is formed by deposition such as LPCVD (Low Pressure
Chemical Vapor Deposition), the internal stress is adjusted by setting the conditions of annealing
after deposition. However, since the precision with which the internal stress can be controlled by
setting the conditions for annealing is not high, the annealing conditions are set such that the
internal stress remains in any of the allowable directions of tension and compression with a
considerable margin.
[0004]
In the condenser microphone in which one end of the diaphragm is a free end disclosed in Patent
Document 1, the influence of the internal stress of the diaphragm on the sensitivity is reduced.
However, since the structure for supporting the diaphragm is complicated, there is a problem
that the manufacturing yield is lowered and the manufacturing cost is increased. Also, in the
conventional condenser microphone, since the plate serving as the counter electrode of the
condenser and the diaphragm are directly opposed to each other through the space of the
pressure chamber, dew condensation occurs between the plate and the diaphragm in a high
humidity environment Also, there is a problem that a leak current is generated between the
opposing electrodes and the sensitivity of the microphone is lowered. Furthermore, when socalled pull-in occurs, there is a possibility that the counter electrode may be shorted, and there is
also a problem that a circuit failure or a breakdown due to a spark occurs due to the short.
[0005]
The Institute of Electrical Engineers of Japan MSS-01-34
[0006]
11-05-2019
2
The present invention is created to solve the above-mentioned problems, and it is a first object of
the present invention to provide a diaphragm whose internal stress is controlled with high
precision, a method of manufacturing the same, and a condenser microphone using the
diaphragm. To aim.
Another object of the present invention is to provide a highly sensitive and stable performance
condenser microphone that prevents current leakage and short circuit between the opposing
electrodes of the condenser.
[0007]
(1) A method of manufacturing a diaphragm to achieve the above first object comprises: forming
a first thin film by deposition; and forming a second thin film having different internal stress
from the first thin film. Adjusting an internal stress of a diaphragm made of a multilayer film
having one thin film and the second thin film. When the diaphragm having the required function
is formed of a single layer thin film, the single layer thin film must have all the chemical,
mechanical or electrical characteristics to realize the function required of the diaphragm. It is
extremely difficult to find process conditions that can control the internal stress of a single layer
thin film with high precision while meeting these requirements, so when forming a diaphragm
with a strict specification of internal stress requirements with a single layer thin film, The
manufacturing yield will be reduced. When the diaphragm is formed of a multilayer film, each
thin film can mutually complement the function required for the diaphragm. Therefore, when
manufacturing a multilayer film diaphragm, for example, a first thin film for achieving the
required electrical characteristics is deposited, and then the second internal stress of the entire
multilayer film is precisely adjusted. By forming a thin film of the above, it is possible to improve
the internal stress characteristics which are mechanical characteristics while satisfying the
required electrical characteristics.
[0008]
(2) In the method of manufacturing the diaphragm, the internal stress of the first thin film is
reduced by annealing the first thin film, and the thickness of the second thin film deposited on
the surface of the first thin film Adjusting the internal stress of the multilayer film. By annealing
the deposited first thin film, the internal stress of the first thin film can be reduced and
approximately eliminated, but its control accuracy is not high. For the second thin film deposited
11-05-2019
3
on the surface of the first thin film, only the function of stress adjustment can be determined, so
the internal stress of the multilayer film can be finely adjusted with the film thickness. In this
way, it is possible to almost completely remove the internal stress of the diaphragm made of a
multilayer film having the first and second thin films.
[0009]
(3) The method for manufacturing the diaphragm reduces the internal stress of the first thin film
by annealing the first thin film, and deposits the second thin film on the surface of the first thin
film, Adjusting the internal stress of the multilayer film by etching a portion of the second thin
film may be included. By annealing the deposited first thin film, the internal stress of the first
thin film can be reduced and approximately eliminated, but its control accuracy is not high. Since
the second thin film to be deposited on the surface of the first thin film can be determined only
for its stress control function, the internal stress of the multilayer film is delicately adjusted by
etching the second thin film. Can. In this way, it is possible to almost completely remove the
internal stress of the diaphragm made of a multilayer film having the first and second thin films.
[0010]
(4) In the method of manufacturing the diaphragm, the second thin film is deposited on the
surface of the first thin film, and the first thin film and the second thin film are annealed at the
same time. Adjusting the internal stress of the multilayer film having the second thin film.
[0011]
(5) A diaphragm for achieving the first object comprises: a first thin film; and a second thin film
having an internal stress different from that of the first thin film adhered to the surface of the
first thin film. And a multi-layered film whose entire circumference is fixed.
When the diaphragm having the required function is formed of a single layer thin film, the single
layer thin film must have all the chemical, mechanical or electrical characteristics to realize the
function required of the diaphragm. It is extremely difficult to find process conditions that can
control the internal stress of a single layer thin film with high precision while meeting these
requirements, so when forming a diaphragm with a strict specification of internal stress
requirements with a single layer thin film, The manufacturing yield will be reduced. When the
diaphragm is formed of a multilayer film, each thin film can mutually complement the function
11-05-2019
4
required for the diaphragm. Thus, the diaphragm of the multilayer film, for example, deposits a
first thin film that achieves the required electrical characteristics, and then a second thin film for
precisely adjusting the internal stress of the entire multilayer film. Since it can be manufactured
by the method of forming, internal stress characteristics can be improved.
[0012]
(6) The second thin film may be narrower than the first thin film, and may have a shape having a
plurality of radially arranged plural form elements. By forming the thin film having the function
of adjusting stress into a shape having a predetermined form element radially arranged in a
plurality, it is possible to realize an internal stress distribution in which the displacement of the
multilayer film becomes constant in the circumferential direction.
[0013]
(7) The first thin film may be made of polycrystalline silicon. The second thin film may be made
of an insulator. The thin film made of an insulator includes a silicon oxide film (SiO2), a silicon
nitride film (Si3N4), a silicon oxynitride film (SiON), an alumina film (Al2O3), and the like.
[0014]
(8) The first thin film may be made of polycrystalline silicon doped with an impurity such as
phosphorus (P). The second thin film may be made of polycrystalline silicon or amorphous silicon
(amorphous silicon) substantially free of impurity diffusion.
[0015]
(9) A condenser microphone for achieving the above first object comprises a plate having a fixed
electrode and a through hole, and a movable electrode, and is vibrated by an acoustic wave
according to any one of claims 5 to 8. A diaphragm, and a spacer which supports the plate and
the diaphragm while insulating it, and which forms an air gap between the fixed electrode and
the movable electrode.
[0016]
11-05-2019
5
(10) A condenser microphone for achieving the above second object supports a plate having a
fixed electrode and a through hole, a diaphragm having a movable electrode, which is vibrated by
a sound wave, and insulating the plate and the diaphragm A spacer forming an air gap between
the fixed electrode and the movable electrode, wherein the diaphragm is formed of a conductive
first thin film and an insulator, or a polycrystal substantially free of impurities. The second thin
film is a composite film having a second thin film of silicon or amorphous silicon, and the second
thin film is provided on the plate side of the first thin film.
Since the insulating or high-resistance second thin film of the diaphragm is provided on the plate
side of the conductive first thin film, even if condensation occurs between the plate and the
diaphragm in a high humidity environment, Leakage current is prevented from occurring
between the opposing electrodes of the capacitor to lower the sensitivity of the microphone.
Further, even when pull-in occurs, a short circuit between the opposing electrodes is prevented,
and the occurrence of a breakdown phenomenon due to a circuit failure or a spark due to such a
short circuit is avoided. Note that the order of operations of the method described in the claims is
not limited to the order of description unless it is a technical hindrance, and may be performed in
any order, and may be performed simultaneously. It is also good.
[0017]
Hereinafter, embodiments of the present invention will be described based on a plurality of
examples. First Embodiment FIG. 1A is a schematic view showing a configuration of a condenser
microphone 1 according to a first embodiment. The condenser microphone 1 includes a sound
sensing unit depicted as a cross-sectional view in FIG. 1A and a detection unit depicted as a
circuit diagram in FIG. 1A.
[0018]
(Structure of the sound sensing unit) The respective ends of the back plate 10 and the diaphragm
30 are connected to the spacer 44, and are supported in parallel with each other with the
pressure chamber 46 formed between the both by the spacer 44 There is. A back plate 10 is
provided on the sound source side of the diaphragm 30. The back plate 10 is formed with a
plurality of acoustic holes 18 which are through holes for propagating the sound waves to the
diaphragm 30. A base 40 forming a side wall surface 52 of the pressure buffer chamber 33 is
11-05-2019
6
provided on the side opposite to the back plate 10 of the diaphragm 30.
[0019]
The back plate 10 is formed of a disk-shaped portion which is not fixed to the insulating film 45
of the conductive film 22. The diaphragm 30 is composed of a disk-shaped portion not fixed to
the insulating film 43 of the first thin film 32 and a disk-shaped portion not fixed to the
insulating film 45 of the second thin film 14. The first thin film 32 and the conductive film 22
having conductivity are made of, for example, polycrystalline Si (silicon) doped with an impurity,
and constitute a counter electrode of the parallel plate capacitor. The second thin film 14
adjusting the internal stress of the diaphragm 30 is made of an insulator such as Si3N4. The
second thin film 14 is provided on the back plate 10 side of the first thin film 32. The spacer 44
is composed of the insulating film 45 constituting the side wall surface 16 of the pressure
chamber 46 and the portion of the first thin film 32, the second thin film 14 and the conductive
film 22 outside the side wall surface 16 of the pressure chamber 46. It is done. The base 40 is
composed of the insulating film 43 and the base film 51. The insulating film 43 and the
insulating film 45 are made of, for example, SiO2. The base film 51 is made of, for example,
single crystal silicon.
[0020]
The internal stress of the first thin film 32 is adjusted to approximately zero. A portion adjusting
the internal stress of the diaphragm 30 of the second thin film 14, that is, the diaphragm 30 of
the second thin film 14 is formed over the entire portion of the first thin film 32 constituting the
diaphragm 30. The whole part is fixed. A small tensile stress remains in the second thin film 14.
The internal stress of the second thin film 14 is adjusted by the film thickness of the second thin
film 14.
[0021]
Further, since the insulating second thin film 14 of the diaphragm 30 is provided on the plate 10
side of the conductive first thin film 32, dew condensation occurs between the plate 10 and the
diaphragm 30 in a high humidity environment. Even when it occurs, the second thin film 14
exerts an insulating function to prevent a leak current from being generated between the
opposing electrodes of the capacitor to reduce the sensitivity of the microphone 1. Furthermore,
11-05-2019
7
even when so-called pull-in occurs between the opposing electrodes, the interposition of the
second thin film 14 prevents a short circuit between the opposing electrodes, thereby causing a
circuit failure due to such a short circuit or a breakdown due to sparks. To avoid.
[0022]
(Structure of Detection Unit) A lead wire 104 connected to one end of the resistor 100 is
connected to the conductive first thin film 32 forming the counter electrode of the diaphragm
30. A lead wire 106 connected to the ground is connected to the conductive film 22 constituting
the counter electrode of the back plate 10. The other end of the resistor 100 is connected to a
lead 108 connected to the output end of the bias power supply circuit 102. As the resistor 100,
one having a large resistance value is used. Specifically, the resistor 100 desirably has an
electrical resistance of G order. A lead wire 114 connected to one end of the capacitor 112 is
connected to the input end of the preamplifier 110. The lead wire 104 connecting the diaphragm
30 and the resistor 100 is also connected to the other end of the capacitor 112.
[0023]
(Operation of Condenser Microphone) When a sound wave passes through the acoustic hole 18
of the back plate 10 and propagates to the diaphragm 30, the diaphragm 30 vibrates by the
sound wave. When the diaphragm 30 vibrates, the distance between the back plate 10 and the
diaphragm 30 changes, so the capacitance of the capacitor formed by the diaphragm 30 and the
back plate 10 changes. Since the diaphragm 30 is connected to the resistor 100 having a large
resistance value, even if the capacitance of the capacitor changes due to the vibration of the
diaphragm 30, the charge stored in the capacitor hardly flows through the resistor 100. . That is,
the charge stored in the capacitor formed by the diaphragm 30 and the back plate 10 can be
regarded as not changing. Therefore, it is possible to extract the change in capacitance of the
capacitor as a change in voltage between the diaphragm 30 and the back plate 10. The capacitor
microphone 1 outputs a very slight change in the capacitance of the capacitor as an electrical
signal by amplifying the change in voltage of the diaphragm 30 with respect to the ground by the
preamplifier 110. That is, the condenser microphone 1 converts a change in sound pressure
applied to the diaphragm 30 into a change in capacitance of the capacitor, and converts a change
in capacitance of the capacitor into a change in voltage, thereby correlating with the change in
sound pressure Output an electrical signal.
[0024]
11-05-2019
8
(Manufacturing Method) FIGS. 2 and 3 are cross-sectional views showing a method of
manufacturing the condenser microphone 1 according to the first embodiment. First, as shown in
FIG. 2A, a base film 51 and an insulating film 43 are formed. Specifically, for example, the
insulating film 43 is formed by depositing SiO 2 on the surface of the single crystal silicon
substrate which is the base film 51 by the CVD method. Although the insulating film 43 may be
formed by thermal oxidation of a single crystal silicon substrate, in order to equalize the etching
rate of the insulating film 45 made of SiO 2 and the insulating film 43 made of SiO 2 described
later, It is preferable to
[0025]
Next, as shown in FIG. 2B, the first thin film 32 is deposited on the surface of the insulating film
43. Specifically, polycrystalline Si is deposited on the surface of the insulating film 43 by, for
example, the LPCVD method. The deposited polycrystalline Si film may be doped with an
impurity serving as a donor or an acceptor by ion implantation, or may be doped in situ when
depositing the polycrystalline Si film.
[0026]
Next, by annealing the first thin film 32, the internal stress of the first thin film 32 is reduced and
almost eliminated. Specifically, for example, the internal stress is substantially removed by
heating a polycrystalline Si film in which, for example, P is diffused as an impurity to about
1000.degree. However, since the control accuracy for removing internal stress is not so high, for
example, compressive stress may occur in the first thin film 32 as an adjustment error.
[0027]
Next, as shown in FIG. 2C, a second thin film 14 is deposited on the surface of the first thin film
32. Specifically, Si 3 N 4 is deposited on the surface of the first thin film 32 by LPCVD, for
example. The film thickness of the second thin film 14 is set to the minimum film thickness in the
range in which the minimum tensile stress which can almost completely cancel the compressive
stress which may occur as the maximum adjustment error of the internal stress of the first thin
film 32 is generated. Ru. Furthermore, when forming a film of Si 3 N 4, a method may be used in
11-05-2019
9
which the flow ratio of H 2 Cl 2 and NH 3 and the film forming temperature are adjusted to
change the internal stress in advance. In this way, it is possible to almost completely remove the
internal stress of the multilayer film consisting of the first thin film 32 and the second thin film
14.
[0028]
Next, as shown in FIG. 2D, the first thin film 32 and the second thin film 14 are etched to obtain
a desired pattern. Specifically, a mask is formed on the surface of the second thin film 14 by
lithography, and the second thin film 14 and the first thin film 32 are formed using a mixed gas
of CH4 and CHF3, a mixed gas of Cl2 and O2, etc. Etch.
[0029]
Next, as shown in FIG. 2E, an insulating film 45 is deposited on the surface of the second thin
film 14. Specifically, for example, SiO 2 is deposited by the CVD method.
[0030]
Next, as shown in FIG. 3F, the conductive film 22 is formed on the surface of the insulating film
45. Specifically, for example, polycrystalline Si is deposited on the surface of the insulating film
45 by the LPCVD method. The deposited polycrystalline Si film may be doped with an impurity
serving as a donor or an acceptor by ion implantation, or may be doped in situ when depositing
the polycrystalline Si film.
[0031]
Next, as shown in FIG. 3G, an acoustic hole 18 is formed in the conductive film 22. Specifically, a
mask is formed on the surface of the conductive film 22 by lithography, and the conductive film
22 is etched by a mixed gas of Cl 2 and O 2.
[0032]
11-05-2019
10
Next, as shown in FIG. 3H, the base film 51 is etched to form a part of the pressure buffer
chamber 33. Specifically, a mask having a circular opening corresponding to the side wall surface
52 of the pressure buffer chamber 33 is formed on the surface of the base film 51 by
lithography, and the base film 51 is etched using SF 6 gas.
[0033]
Next, as shown in FIG. 3I, the insulating film 43 and the insulating film 45 are etched to form the
remaining portion of the pressure buffer chamber 33 and the pressure chamber 46. Specifically,
the insulating film 43 and the insulating film 45 are etched using an HF solution or the like using
the base film 51 and the conductive film 22 as a mask. As a result, the disk-shaped portions of
the first thin film 32 and the second thin film 32 are opened with an air gap therebetween, and
the sound sensing unit of the condenser microphone 1 is completed.
[0034]
Second Embodiment FIG. 4 is a schematic view showing a condenser microphone 2 according to
a second embodiment. Components corresponding to the components described in the first
embodiment are assigned the same reference numerals. As shown in FIG. 4, the conductive first
thin film 32 may be formed on the back plate 10 side of the second thin film 14 for adjusting
internal stress. That is, either the first thin film 32 or the second thin film 14 may be formed first.
However, when the first thin film 32 is formed on the back plate 10 side of the second thin film
14, the second thin film 14 does not exhibit the insulating function between the opposing
electrodes of the capacitor.
[0035]
Third Embodiment FIGS. 5 and 6 are diagrams for explaining a condenser microphone 3
according to a third embodiment. Components corresponding to the components described in the
first embodiment are assigned the same reference numerals. The portion of the second thin film
14 constituting the diaphragm 30 is fixed to a part of the portion constituting the diaphragm 30
of the first thin film 32. The portion of the second thin film 14 constituting the diaphragm 30 has
a fragmentary shape which is arranged at equal intervals in the circumferential direction of the
11-05-2019
11
diaphragm 30 as shown in FIGS. 5 (B) and 5 (C). It may be a radiation shape as shown in FIG. 6
(A), or may be a shape concentric with the diaphragm 30 as shown in FIG. 6 (B).
[0036]
The plan view shape of the diaphragm 30 may be circular as shown in FIG. 5 (B) or rectangular
as shown in FIG. 5 (C). That is, the plan view shape of the pressure chamber 46 and the pressure
buffer chamber 33 may be circular or rectangular.
[0037]
The capacitor microphone 3 according to the third embodiment is a mask for etching the first
thin film 32 in the step shown in FIG. 2D described as one step of the method of manufacturing
the capacitor microphone 1 according to the first embodiment. It can be manufactured by
forming the mask for etching the second thin film 14 into a different shape.
[0038]
By forming the portion of the second thin film 14 that makes up the diaphragm 30 smaller than
the portion of the first thin film 32 that makes up the diaphragm 30, the film thickness of the
second thin film 14 is advantageous for film formation. Film thickness can be set.
That is, after setting the film thickness that can ensure high uniformity and the film thickness
that increases the throughput, it is possible to set the shape of the portion of the second thin film
14 that constitutes the diaphragm 30 from which the target stress is obtained.
[0039]
Fourth Embodiment FIG. 7 is a schematic view showing a condenser microphone 4 according to a
fourth embodiment. Components corresponding to the components described in the first
embodiment are assigned the same reference numerals. The diaphragm 30 may be partially
disconnected from the spacer 44. Specifically, the portion of the first thin film 32 constituting the
diaphragm 30 may be largely separated from the portion of the first thin film 32 constituting the
spacer 44. With this configuration, the rigidity of the peripheral portion of the diaphragm 30 can
11-05-2019
12
be reduced, so that the amplitude of the diaphragm 30 can be increased and the sensitivity of the
condenser microphone 4 can be increased.
[0040]
Fifth Embodiment In the embodiments described above, the adjustment of the internal stress of
the first thin film 32 constituting the diaphragm 30 and the adjustment of the internal stress of
the entire diaphragm 30 by the second thin film 14 will be described. did. However, the internal
stress of the entire diaphragm 30 can also be adjusted by simultaneously adjusting the internal
stress of the first thin film 32 and the second thin film 14. Specifically, for example,
polycrystalline Si is deposited by the LPCVD method to form a first thin film 32 doped with an
impurity such as P, and thereafter, without the annealing step, the impurity is not doped by the
LPCVD method. Crystalline Si is deposited to form the second thin film 14, and then the internal
stress of the first thin film 32 and the second thin film 14 is simultaneously adjusted by the
annealing process. As shown in FIG. 8, polycrystalline Si deposited by LPCVD and doped with P
has a large tensile stress before annealing, and the tensile stress decreases with the increase of
the annealing temperature, and it is about 1000 ° C. The stress is removed and the compressive
stress increases as the annealing temperature increases. Conversely, polycrystalline Si deposited
by LPCVD and doped with no impurities has a large compressive stress before annealing, and the
compressive stress gradually decreases as the annealing temperature increases. On the other
hand, amorphous Si which is not doped with impurities has a large compressive stress before
annealing, but the compressive stress rapidly decreases with the increase of the annealing
temperature, and the stress is removed at 750 ° C. As the annealing temperature increases, it
will have tensile stress. Therefore, by utilizing these characteristics, the internal stress of
polycrystalline Si doped with P and the internal stress of polycrystalline Si or amorphous Si not
doped with an impurity mutually cancel each other, The annealing temperature is adjusted so
that the sum of the internal stresses, that is, the internal stress of the composite film consisting of
the first thin film 32 and the second thin film 14 is almost completely removed or becomes a
very small tensile stress. The graphs shown in FIG. 8 to FIG. 10 show experimental results
obtained by annealing using a rapid thermal annealing (RTA) apparatus.
[0041]
In the case of a laminated film of polycrystalline Si doped with P and polycrystalline Si not doped
with impurities, the annealing temperature can be lowered. As shown in FIG. 9, for example, if the
film thickness ratio to the entire laminated film of a polycrystalline Si layer doped with P is 76 to
800 to 900 ° C. and the film thickness ratio to 68, 590 to 830 ° C. Depending on the annealing
11-05-2019
13
temperature, the internal stress of the laminated film can be almost completely removed or the
tensile stress (for example, 0 to 5 MPa) can be extremely small. On the other hand, in the case of
a single layer film, a high annealing temperature of more than 930 ° C. is required to make the
internal stress a very small tensile stress (eg, 0 to 5 MPa).
[0042]
Similarly, even in the case of a composite film of a combination of polycrystalline Si doped with P
and amorphous Si not doped with impurities, the internal stress of the composite film is almost
completely removed by setting the annealing temperature. It can be adjusted to have a very low
tensile stress. For example, as shown in FIG. 10, when the annealing temperature exceeds 930 °
C. regardless of the film thickness ratio, the internal stress of the composite film is almost
completely removed or extremely small tensile stress (for example, 0 to 5 MPa) . On the other
hand, when the annealing temperature is set low, in the combination of polycrystalline Si doped
with P and amorphous Si not doped with impurities, any internal stress is obtained by adjusting
the film thickness ratio and the annealing temperature. be able to. C. to 930.degree. C. is not
preferable as the setting of the annealing temperature because amorphous crystallizes.
[0043]
FIG. 1A is a schematic view showing a condenser microphone according to a first embodiment of
the present invention. (B) is a top view which shows the diaphragm by 1st Example of this
invention. FIG. 7 is a cross-sectional view showing the method of manufacturing the condenser
microphone according to the first embodiment of the present invention. FIG. 7 is a cross-sectional
view showing the method of manufacturing the condenser microphone according to the first
embodiment of the present invention. FIG. 5 is a schematic view showing a condenser
microphone according to a second embodiment of the present invention. (A) is a schematic
diagram which shows the condenser microphone by 3rd Example of this invention. (B) and (C)
are top views which show the diaphragm by 3rd Example of this invention. The top view which
shows the diaphragm by 3rd Example of this invention. (A) is a schematic view showing a
condenser microphone according to a fourth embodiment of the present invention. (B) is a top
view which shows the diaphragm by 4th Example of this invention. It is a graph which shows the
relationship between the internal stress of silicon-type material, and annealing temperature. It is
a graph which shows the relationship between the internal stress of a silicon ¦ silicone multilayer
film, and annealing temperature. It is a graph which shows the relationship between the internal
stress of a silicon ¦ silicone multilayer film, and annealing temperature.
11-05-2019
14
Explanation of sign
[0044]
1, 2, 3, 4: capacitor microphone, 10: back plate, 14: second thin film, 18: acoustic hole, 30:
diaphragm, 32: first thin film, 44: spacer, 44: pressure Chamber (air gap).
11-05-2019
15