KR101952071B1 - MEMS Capacitive Microphone - Google Patents

Abstract

The present invention relates to a microphone which can form, in an inner region of a diaphragm, a plurality of comb sensing units composed of a plurality of movable comb fingers attached to the diaphragm and a plurality of fixed comb fingers attached to a support, thereby significantly increasing a sensing area. In addition, a parasitic capacitance is small due to a small area of the support fixed to a substrate. Accordingly, a MEMS capacitive microphone with a high signal-to-noise ratio can be realized.

Description

[0001] MEMS CAPACITIVE MICROPHONE [0002]

The present invention relates to a MEMS capacitive microphone for sensing a capacitance change due to a sound wave in a plurality of comb sensing units formed in an inner region of a diaphragm.

In general, MEMS capacitive microphones have capacitances between a diaphragm that is displaced in proportion to the intensity of a sound pressure and a backplate disposed opposite to the diaphragm, As shown in FIG.

U.S. Patent Publication No. 07146016, U.S. Patent Application No. 08921956, U.S. Patent No. 08422702, U.S. Patent Application Publication No. 2002-0294464, and U.S. Patent Application Publication No. 2013-0108084 disclose MEMS capacitive microphones Are illustrated.

In the illustrated patent, a number of perforations are formed in the back plate to smoothly transfer sound energy to the diaphragm (Perforated Backplate). However, if the perforation is large or the number of perforations is large, the effective area of the back plate becomes small and the electrostatic capacity becomes too small. Further, when the bias voltage between the diaphragm and the back plate is increased, there is a problem that the diaphragm is attached to the back plate by the electrostatic force.

On the other hand, dual backplate MEMS capacitive microphones, in which two back plates opposed to each other in the diaphragm are disposed, are disclosed in PCT Laid-Open Patent Publication No. 2011/025939, U.S. Patent No. 09503823, It is illustrated in Publication No. 2014-0072152.

In the MEMS capacitive microphone using the dual back plate, the electrostatic force due to the bias voltage acts in both directions of the diaphragm, so that there is no problem that the diaphragm sticks to the back plate. In addition, since the change in capacitance is generated in a differential manner, the MEMS capacitor microphone has an advantage of excellent linearity and small noise compared to a MEMS capacitive microphone using a single backplate.

However, in the MEMS capacitive microphone using the back plate, noise due to the air flow between the diaphragm and the back plate always occurs, and there is a limitation in suppressing the noise. Therefore, it is known that the signal-to-noise ratio is limited to 70 dB in dual backplate MEMS capacitive microphones.

Meanwhile, as exemplified in U.S. Patent Application Publication No. 2014-0197502, a comb sensing MEMS capacitive microphone has no back plate, so that a signal signal having improved signal strength compared to a conventional dual back plate MEMS capacitive microphone Noise ratio can be realized. However, since the microphone exemplified in the patent is arranged at the edge of the diaphragm having a limited length, the number of combs is limited, so that the sensitivity is low and the counter electrode is fixed to the substrate So that a large parasitic capacitance occurs through the substrate. The parasitic capacitance through the substrate causes noise due to dielectric loss. In addition, when a plurality of comb fingers are formed, since the vent effect between the comb fingers is so large that it can not be ignored, low frequency characteristics may be deteriorated. In addition, since the comb finger is disposed at the edge of the diaphragm, it can not be applied to an edge clamped diaphragm where an edge such as a corrugated diaphragm is fixed to the substrate.

US Patent Registration No. 07146016 (registered on December 5, 2006) U.S. Patent Publication No. 08921956 (registered on December 30, 2014) U.S. Patent Publication No. 08422702 (registered on April 16, 2013) U.S. Published Patent Application No. 2012-0294464 (November 22, 2012) U.S. Published Patent Application No. 2013-0108084 (Feb. PCT Published Patent Publication No. 2011/025939 (March 23, 2011) United States Patent Publication No. 09503823 (registered on November 22, 2016) U.S. Published Patent Application No. 2014-0072152 (March 13, 2014). U.S. Published Patent Application No. 2014-0197502 (July 17, 2014)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a MEMS capacitive microphone of a comb sensing type which is excellent in sensitivity and signal-to-noise ratio, excellent in low frequency characteristics, and applicable to an edge clamped diaphragm.

In the MEMS-capacitive microphone of the present invention, a plurality of fixed comb fingers attached on a certain area of the diaphragm, and a plurality of fixed comb fingers attached to a support which is vertically spaced from the diaphragm and traverses the diaphragm, And a comb sensing unit disposed on both sides of the finger at regular intervals. When the sound wave is applied, the diaphragm is shifted up and down, so that the floating comb finger attached to the diaphragm also shifts up and down. On the other hand, fixed comb fingers attached to a support having a large rigidity do not change. Since the fixed comb fingers are shifted upward or downward with respect to the floating comb fingers, the capacitance between the floating comb fingers and the fixed comb fingers changes in proportion to the intensity of the sound waves. When the change in capacitance of the comb sensing portion is detected, .

Since the comb sense unit can be formed in a large number in the diaphragm, the sensing area can be greatly increased as compared with the conventional comb sensing MEMS capacitive microphone in which the comb sense unit is formed at the edge of the diaphragm. In addition, since the area of the support fixed to the substrate is small, the parasitic capacitance through the substrate is small, and noise due to this is low. As a result, the MEMS capacitive microphone of the present invention can greatly improve the signal-to-noise ratio.

In addition, since the floating comb finger is formed on the diaphragm and the diaphragm is closed, the vent effect due to the gap between the comb fingers generated in the conventional comb sensing method is not generated, which is advantageous in that the low frequency characteristic is excellent.

In addition, since the comb sensing portion is formed inside the diaphragm, an edge released diaphragm in which the edge is separated from the substrate, as well as an edge clamped diaphragm in which the edge is fixed to the substrate, for example, It can also be applied to a corrugated diaphragm.

The MEMS capacitive microphone of the present invention provides a high signal-to-noise ratio because the MEMS capacitive microphone has excellent low-frequency characteristics, but has a small sensing area and small noise.

1 shows a planar structure of a MEMS capacitive microphone of the present invention.
Figure 2 shows a cross section of a structure in which a floating comb finger and a stiffener are formed on top of the diaphragm and a fixed comb finger is shifted upward relative to the floating comb finger.
Figure 3 shows a cross section of a structure in which a floating comb finger and a stiffener are formed at the bottom of the diaphragm and a fixed comb finger is shifted downward relative to the floating comb finger.
4A and 4B show cross sections of a structure in which a floating comb finger and a stiffener are formed on the top and bottom of the diaphragm and a fixed comb finger is formed on the upper and lower sides of the floating comb finger.
Figure 5 shows a planar structure in which two and three struts and supports are combined.
6A to 6C show a manufacturing process of a capacitive microphone of the present invention in which a floating comb finger and a stiffener are formed on top of a diaphragm and a fixed comb finger is shifted upward relative to a floating comb finger.
7 shows a manufacturing process of a capacitive microphone of the present invention in which a floating comb finger and a stiffener are formed at the bottom of the diaphragm and a fixed comb finger is shifted downward relative to the floating comb finger.
8 shows a manufacturing process of a capacitive microphone of the present invention in which a floating comb finger and a stiffener are formed on the upper and lower sides of the diaphragm and fixed comb fingers are formed on upper and lower sides of the floating comb finger.
9 shows a planar structure of a MEMS capacitive microphone of the present invention when the diaphragm is circular.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and the inventor can properly define the concept of the term to describe its invention in the best possible way And should be construed in accordance with the principles and meanings and concepts consistent with the technical idea of the present invention.

Therefore, the embodiments described in the present specification and the drawings are only the most preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents It should be understood that water and variations may be present.

Before describing the present invention with reference to the accompanying drawings, it should be noted that the present invention is not described or specifically described with respect to a known configuration that can be easily added by a person skilled in the art, Let the sound be revealed.

1 shows a planar structure of a MEMS capacitive microphone provided in the present invention. The structure of the diaphragm was exemplified by an edge released diaphragm from which the diaphragm was separated from the substrate.

The diaphragm, which is separated from the substrate by the gap between the lower substrate and the wing, is suspended from the substrate by a supporting spring. When the sound wave is applied, the diaphragm is displaced up and down by the pressure of the sound wave. The diaphragm is provided with a plurality of stiffeners for reinforcing the stiffness of the diaphragm. The diaphragms are mechanically fixed to the diaphragm with both ends fixed to the substrate and spaced upward or downward from the diaphragm and the stiffener. A large number of supporting beams (supporting beams) are formed. A plurality of comb fingers (referred to as moving comb fingers) having a predetermined thickness, width, and length are disposed at predetermined intervals on a certain area of the diaphragm. On the other hand, the support supports a plurality of comb fingers (referred to as stationary comb fingers) having a certain thickness, width, and length arranged at equal intervals on both sides of the liquid comb finger. At this time, the fixed comb finger is shifted in the vertical direction based on the floating comb finger. Since the diaphragm, the support, the floating comb finger, and the fixed comb finger are made of conductors, there is a capacitance between the floating comb finger and the fixed comb finger, which is fixed to the substrate of the support spring, It becomes possible to measure at the point.

When the sound wave is applied, the diaphragm is shifted in the vertical direction, and the liquid comb finger is also shifted in the vertical direction. On the other hand, since the fixed comb finger is attached to a rigid support, there is little variation due to sound waves. Thus, the capacitance between the floating comb finger and the fixed comb finger changes, and the intensity of the sound wave is obtained by measuring the change in capacitance. In the present invention, a region consisting of a floating comb finger and a fixed comb finger for sensing a sound wave is referred to as a comb sensor. In FIG. 1, three support bars and four comb sense portions are formed. The number of supports and comb sense portions can be increased according to need, and the stiffener and the support can be crossed and connected as illustrated in FIG.

Since the gap between the diaphragm and the wing is small within a few micrometers, the sound wave can not escape almost under the diaphragm. Therefore, in order to prevent the diaphragm from being broken when a large pressure wave is applied, a separate vent hole ) Is preferably formed.

The flow comb finger and the stiffener are preferably formed by the same process, and depending on the design, the flow comb finger and the stiffener may be attached to the top of the diaphragm or may be attached to the bottom of the diaphragm. Further, after the supporting bar is formed above and below the diaphragm, fixed comb fingers may be formed in pairs in the vertical both directions of the floating comb finger. The cross section (section A-A ') of the comb sense unit of FIG. 1 and the cross section (cross section B-B') of the support and the diaphragm and the stiffener are illustrated in FIGS. have.

FIG. 2 (a) shows a cross section of the comb sensing unit in which the floating comb finger and the stiffener are attached to the upper side of the diaphragm and the fixed comb finger is shifted upward relative to the floating comb finger. As shown in (B) of FIG. 2, at the portion where the support, the diaphragm and the stiffener intersect, the support is grooved upward to avoid collision with the stiffener.

3 (A) shows a cross section of the comb sensing unit in which the floating comb finger and the stiffener are attached to the lower side of the diaphragm and the fixed comb finger is shifted downward relative to the floating comb finger. As shown in (B) of FIG. 6A, at the portion where the support, the diaphragm and the stiffener intersect, the support member has a groove downward to avoid collision with the stiffener.

4A shows a cross section of the comb sensing unit in the case where the floating comb finger and the stiffener are attached to the upper and lower sides of the diaphragm and the fixed comb fingers are formed on the upper and lower sides of the floating comb finger, respectively. At this time, the upper fixed comb finger shifts upward with reference to the upper flow comb finger, and the lower fixed comb finger shifts downward with reference to the lower floating comb finger. In this structure, the capacitance change between the upper flow comb finger and the upper fixed comb finger and the capacitance change between the lower floating comb finger and the lower fixed comb finger are reversed, so that the differential capacitance change can be detected. As shown in (B) of FIG. 4B, in order to avoid collision with the diaphragm and the stiffener at the portion where the support, the diaphragm and the stiffener intersect, the upper support member is grooved upward and the lower support member is recessed downward.

On the other hand, in order to further increase rigidity, the stiffener and the support base may be connected to each other in parallel, as shown in Fig. 5 (A), or in parallel with each other as shown in Fig. 5 (B).

Further, the stiffness may be increased by connecting one or more stiffeners and / or supports to each other in various polygonal shapes such as triangular, square, and hexagonal.

Furthermore, by connecting the stiffener and / or the support, it is of course possible to connect them in all the more various forms. For example, a stiffener configured in a polygonal shape and / or a stiffener and / or a support in a form parallel to a support are combined to form a variety of shapes. Another example is the mesh shape through the above polygonal shape.

The floating comb fingers and the fixed comb fingers are small in width, large in thickness, and large in length, and the smaller the interval between the floating comb fingers and the fixed comb fingers, the larger the capacitance is. It is preferable that the degree of deviation of the fixed comb finger is about 1/2 of the thickness of the fixed comb finger in terms of sensing a change in capacitance. In addition, it is preferable that the larger the interval between the fixed comb fingers and the fixed comb fingers is, the larger the interval between the fixed comb fingers and the fixed comb fingers is, because the resistance of the air becomes smaller when the diaphragm is shifted by the sound waves. It is preferable that the thickness of the diaphragm is increased because the stiffener and the support are thicker because the stiffener becomes thicker and the diaphragm is reinforced by the stiffener. Further, it is preferable that the support member is spaced apart from the diaphragm and the stiffener at a large interval.

However, in the present invention, the width of the floating comb finger and the fixed comb finger is 1 탆 to 10 탆, the thickness is 2 탆 to 20 탆, and the length is 10 탆 to 100 탆, the gap between the floating comb finger and the fixed comb finger is 0.5 탆 to 5 탆, and the interval between the fixed comb finger and the fixed comb finger is 2 탆 to 20 탆. Further, the width of the stiffener and the support was 1 탆 to 10 탆, the thickness was 2 탆 to 20 탆, and the thickness of the diaphragm was 0.3 탆 to 3 탆. It has been observed that the support can be spaced from 1 탆 to 20 탆 from the diaphragm and the stiffener. Since the capacitance at the comb sensing unit must be measured at the terminals formed on the substrate, the floating comb finger, the fixed comb finger, the diaphragm, and the supporting member must be made of a conductive material.

Hereinafter, a manufacturing method for implementing each structure shown in FIG. 2 to FIG. 4B will be described with reference to FIGS. 6A to 8.

6A to 6C show a manufacturing process of a microphone according to the present invention in which a floating comb finger and a stiffener are formed on the diaphragm while a fixed comb finger is shifted upward with respect to a floating comb finger.

First, a protective layer is formed on the substrate as shown in (a) of FIG. 6A, and an elastic layer pattern having conductivity is formed on the protective layer as shown in (B) of FIG. 6A. The elastic layer pattern forms a diaphragm, a wing and a support spring. In the present invention, a silicon wafer of (100) plane was used as the substrate, a silicon nitride film of 0.5 mu m thickness was used as the protective layer, and polysilicon of 0.5 mu m thickness was used as the elastic layer. Next, as shown in (c) of FIG. 6A, a first conductor filled in a first sacrificial layer pattern is formed. There are various methods of filling the conductor in the sacrificial layer pattern as described above. As a sacrificial layer, an undoped silicon oxide glass (PSG), a phosphosilicate glass (PSG), a borophosphosilicate glass (BPSG), a spin on glass (SOG), and a tetraethyl orthosilicate (TEOS) are etched by RIE (Reactive Ion Etching) A conductive layer such as polysilicon or amorphous silicon or aluminum or titanium or magnesium or nickel or tungsten or copper is deposited and then polished by a CMP (Chemical Mechanical Polishing) method to flatten the trench with the conductor (Method 1). Alternatively, a pattern is formed with a photoresist as a sacrificial layer, or a polyimide as a sacrificial layer is etched to form a trench. Then, a metal such as aluminum or titanium or nickel or tungsten or copper is deposited, and the metal surface layer is etched to form a trench (Method 2). As another method, a pattern is formed using a photoresist as a sacrificial layer, or a polyimide as a sacrificial layer is etched to form a trench, and then nickel or copper is electroless plated to form a conductor (Method 3). In the present invention, "Method 1" was used. USG as a first sacrificial layer and USG as a first sacrificial layer were formed by depositing polysilicon in a thickness of 1 mu m and polished by a CMP method. Subsequently, as shown in Fig. 6B (d), a 2 탆 thick USG was deposited as a second sacrificial layer by using "Method 1 ", a trench was formed to a depth of 2 탆 of the first sacrificial layer, Polysilicon was deposited to a thickness of 1 mu m and polished by the CMP method. Then, as shown in FIG. 6 (e), a third conductor using polysilicon was filled in the third sacrificial layer pattern using USG having a thickness of 4 탆. Then, the bottom surface of the substrate and the protective layer were sequentially etched as shown in FIG. 6C (bar). Finally, when the sacrificial layer is removed as shown in FIG. 6C, a separated diaphragm having a gap from the wing is formed, and a floating comb finger and a strainer attached to the upper portion of the diaphragm are formed. The fixed comb fingers are disposed on both sides of the floating comb fingers at regular intervals and are shifted upward with reference to the floating comb fingers. The fixed comb fingers are fixed to the substrate and supported on the support frame spaced upward from the diaphragm and the stiffener Respectively. As a result, the set of the floating comb finger and the fixed comb finger constitute the comb sense unit in which the capacitance is changed by the sound wave. In the present invention, since a plurality of supporters and comb sense units are formed, each supporter is electrically connected to one electrode. Such an interconnection process is common and is omitted in the illustrated manufacturing process.

7 shows a manufacturing process of a microphone according to the present invention in which a floating comb finger and a stiffener are formed under the diaphragm while a fixed comb finger is shifted downward with respect to a floating comb finger.

7A shows a structure in which respective sacrificial layers and respective conductors and elastic layers filled in each sacrificial layer pattern are stacked on a protective layer. Each of these sacrificial layers and conductors was formed using the "Method 1" process described in Figs. 6A to 6C. A silicon nitride film having a thickness of 0.5 mu m was used as the protective layer, and a polysilicon film having a thickness of 0.5 mu m was used as the elastic layer. All sacrificial layers were made of USG and all conductors were made of polysilicon. The thickness of the first sacrificial layer was 4 mu m, the thickness of the second sacrificial layer was 4 mu m, and the thickness of the third sacrificial layer was 2 mu m. When the substrate, the protective layer and the sacrificial layer are sequentially etched from the bottom surface of the substrate as shown in (b) of FIG. 7 after the step (a) of FIG. 7 is completed, diaphragms separated from each other with a gap are formed, A floating comb finger and a strapper attached to the lower part of the frame are formed. The fixed comb fingers are disposed on both sides of the floating comb fingers at regular intervals and are shifted downward with respect to the floating comb fingers. The fixed comb fingers are fixed to the substrate while being separated from the diaphragm and the stiffener, Respectively. As a result, the set of the floating comb finger and the fixed comb finger constitute the comb sense unit in which the capacitance is changed by the sound wave. In the present invention, since a plurality of supporters and comb sense units are formed, each supporter is electrically connected to one electrode. Such an interconnection process is common, and thus is omitted in the illustrated manufacturing process.

 8 shows a manufacturing process of a microphone according to the present invention in which a floating comb finger and a stiffener are formed on upper and lower portions of a diaphragm while fixed comb fingers are formed on upper and lower sides with respect to a floating comb finger.

Fig. 8 (a) shows a structure in which respective sacrificial layers and respective conductors and elastic layers packed in respective sacrificial layer patterns are stacked on a protective layer. Each of these sacrificial layers and conductors was formed using the "Method 1" process described in Figs. 6A to 6C. A silicon nitride film having a thickness of 0.5 mu m was used as the protective layer, and a polysilicon film having a thickness of 0.5 mu m was used as the elastic layer. All sacrificial layers were made of USG and all conductors were made of polysilicon. The thickness of the first sacrificial layer is 4 占 퐉, the thickness of the second sacrificial layer is 4 占 퐉, the thickness of the third sacrificial layer is 2 占 퐉, the thickness of the fourth sacrificial layer is 4 占 퐉, the thickness of the fifth sacrificial layer is 2 占 퐉, The thickness of the sixth sacrificial layer was 4 mu m. When the substrate, the protective layer and the sacrifice layer are sequentially etched from the bottom surface of the substrate as shown in Fig. 8 (b) after the step (a) of Fig. 8 is completed, a diaphragm separated from the wing with a gap is formed, An upper flow comb finger attached to the upper portion of the diaphragm, and a lower flow comb finger and strainer attached to the lower portion of the diaphragm. The upper and lower movable comb fingers are disposed at equal intervals on both sides of the upper and lower movable comb fingers to form upper fixed comb fingers shifted upward and lower fixed comb fingers shifted downward with reference to the lower flow comb finger . The upper fixed comb finger is attached to the upper support which is fixed to the substrate and spaced upward from the diaphragm and the stiffener and the lower fixed comb finger is attached to the lower support which is fixed to the substrate and spaced downward from the diaphragm and the stiffener. As a result, the set of the floating comb finger, the upper fixed comb finger, and the lower fixed finger forms a comb sense unit in which capacitance changes in a differential manner due to a sound wave. In the present invention, since a plurality of upper supporters, a lower supporter and a comb sensing unit are formed, each upper supporter is electrically connected to one electrode and each lower supporter is connected to another electrode. Such an interconnection process is conventional and is omitted in the illustrated manufacturing process.

Meanwhile, the thickness of each sacrificial layer and the conductor used in each manufacturing process of the present invention is in the range of 2 to 4 탆, but it can be increased to 20 탆 according to the design. Depending on the design, stainless steel, nickel, copper, titanium, glass, polyimide or the like can be used as the material of the substrate in addition to silicon. As the protective layer, a silicon oxide film or polyimide can be used in addition to the silicon nitride film. As the elastic layer, amorphous silicon, aluminum, magnesium, nickel, titanium, vanadium, zirconium, chromium, tungsten, molybdenum and tantalum may be used in addition to polysilicon.

On the other hand, the area of the diaphragm can be designed in the range of 0.1 mm x 0.1 mm (0.01 mm ² ) to 2 mm x 2 mm (4 mm ² ). It is to be understood that the shape of the diaphragm may be rectangular, octagonal, or circular in addition to the square illustrated in Fig.

For example, FIG. 9 illustrates a microphone of the present invention in which a circular diaphragm is used in the form of an edge released diaphragm.

A circular diaphragm mechanically separated from the substrate by a gap from the wing is attached with a stiffener in the circumferential and radial directions. On a certain area of the diaphragm, a floating comb finger is attached, and fixed comb fingers attached to the supporting rods which are spaced apart from the diaphragm and the stiffener and crossing in the radial direction are arranged at equal intervals on both sides of the floating comb finger.

The stiffener and the floating comb finger are attached to the upper, lower or upper and lower portions of the diaphragm so that the fixed comb fingers and the support are positioned above, below, or above and below the diaphragm.

The diaphragm of the MEMS capacitive microphone of the present invention illustrated in Figures 1 and 9 is in the form of an Edge Released Diaphragm. However, according to the present invention, since the comb sense unit is formed inside the diaphragm, it is obvious that the comb sense unit can be applied to an edge clamped diaphragm, for example, a corrugated diaphragm.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or scope of the invention as defined in the appended claims. It is self-evident to those who have.

Therefore, the above-described embodiments are to be considered as illustrative rather than restrictive, and accordingly the present invention is not limited to the above description, but may be modified within the scope of the appended claims and equivalents thereof.

Claims (19)

A diaphragm separated from the substrate by a gap between the wing is suspended from the substrate by a support spring, a plurality of floating comb fingers are attached in a plurality of regions inside the diaphragm to which the stiffener is attached, A plurality of fixed comb fingers arranged at equal intervals on both sides and shifted upward from the floating comb fingers are formed, whereby a number of comb sense units formed with the plurality of floating comb fingers and fixed comb fingers are formed, A plurality of supports spaced vertically from the diaphragm and the stiffener being supported by the substrate and traversing the diaphragm are formed, the fixed comb fingers being attached to the support.
The method according to claim 1,
Wherein the diaphragm is an edge-released diaphragm or an edge-clamped diaphragm.
The method according to claim 1,
Characterized in that the stiffener and the floating comb finger are attached to the top of the diaphragm and the fixed comb finger is shifted upward relative to the floating comb finger and the support is spaced upward from the diaphragm and the stiffener. Microphones.
The method according to claim 1,
Characterized in that the stiffener and the floating comb fingers are attached to the bottom of the diaphragm and the fixed comb fingers are shifted downward relative to the floating comb fingers and the supports are spaced downwardly from the diaphragm and the stiffener. Microphones.
The method according to claim 1,
The stiffener and the floating comb finger are attached to the upper and lower portions of the diaphragm and the upper fixed comb finger is shifted upward with respect to the upper floating comb finger and the lower fixed comb finger is moved with respect to the lower floating comb finger Wherein the upper fixed comb finger is attached to a support stand spaced upward from the diaphragm and support and the lower fixed comb finger is attached to a support stand spaced downwardly from the diaphragm and support. , MEMS capacitive microphones.
The method according to claim 1,
Wherein the width of the floating comb finger and the fixed comb finger is in the range of 1 탆 to 10 탆, the thickness is in the range of 2 탆 to 20 탆, and the length is in the range of 10 탆 to 100 탆.
The method according to claim 1,
The spacing between the fixed comb fingers and the fixed comb fingers is in the range of 0.5 μm to 5 μm and the spacing between the fixed comb fingers and the fixed comb fingers is in the range of 2 μm to 20 μm, And wherein the fixed comb fingers are shifted upward or downward in the range of 1 탆 to 10 탆 with respect to the floating comb finger.
The method according to claim 1,
Wherein the width of the stiffener and the support is in the range of 1 占 퐉 to 10 占 퐉 and the thickness is in the range of 2 占 퐉 to 20 占 퐉.
The method according to claim 1,
Wherein the support is spaced upward or downward from the diaphragm and the stiffener in the range of 1 [mu] m to 20 [mu] m.
The method according to claim 1,
Wherein the stiffener or support is configured to couple one or more parallel sides to one another for rigidity.
The method according to claim 1,
Wherein the material of the substrate is one of silicon, stainless steel, nickel, copper, titanium, glass or polyimide.
The method according to claim 1,
Wherein the material of the protective layer formed on the substrate is one of a silicon nitride film, a silicon oxide film, and a polyimide film.
The method according to claim 1,
Wherein the material of the diaphragm, the wing and the support spring is one of polysilicon, amorphous silicon, aluminum, magnesium, nickel, titanium, vanadium, zirconium, chromium, tungsten, molybdenum or tantalum.
The method according to claim 1,
The material of the floating comb finger, the fixed comb finger, the stiffener,
Wherein the at least one layer is one of polysilicon, amorphous silicon, aluminum, titanium, magnesium, nickel, tungsten or copper.
The method according to claim 1,
Wherein the diaphragm has a thickness in the range of 0.3 탆 to 3 탆 and the planar shape is one of a square, a rectangle, an octagonal or a circle, and an area ranging from 0.01 mm ² to 4 mm ² .
The method according to claim 1,
The stiffener, the floating comb finger, the fixed comb finger,
Forming a sacrificial layer; Forming a trench in the sacrificial layer; Filling the trench with a conductor; Removing the sacrificial layer from the sacrificial layer.
17. The method of claim 16,
Wherein the sacrificial layer is one of USG, PSG, BPSG, SOG, TEOS, photoresist, or polyimide.
17. The method of claim 16,
Wherein the method of forming the trench is one of a method of forming by RIE or photoresist exposure or a method of forming polyimide by etching.
17. The method of claim 16,
Wherein the conductor is any one of polysilicon, amorphous silicon, aluminum, titanium, magnesium, nickel, tungsten, or copper.

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