WO2004031070A1

WO2004031070A1 - Micro movable device

Info

Publication number: WO2004031070A1
Application number: PCT/JP2003/012664
Authority: WO
Inventors: Satoshi Morishita
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2002-10-03
Filing date: 2003-10-02
Publication date: 2004-04-15
Also published as: JPWO2004031070A1; JP4312717B2; AU2003271081A1

Abstract

Formed on a substrate (20) are one or more layers of microcell forming members (43, 48, 49) defining a plurality of microcells (44, 45, 46, 53, 54). The hollow microcell (44) having the greatest dimension in the plurality of microcells (44, 45, 46, 53, 54) has a micro movable section (41) disposed therein. Predetermined microcells (53, 54) in the plurality of microcells (44, 45, 46, 53, 54) are left filled with sacrifice films used when the microcells are formed, whereby the strength in the portions in the vicinity of the microcells (53, 54) can be increased and the trouble of discharging the sacrifice films can be saved.

Description

Description Micro movable device Technical field

The present invention relates to a micro movable device that can be incorporated as a part of an integrated circuit on a substrate, and more particularly to a micro movable device that forms a micro 'elect port' mechanism. Background art

2. Description of the Related Art Conventionally, as a micro movable device that forms a micro, electoral port, mechanical system (MEMS), for example, there is one described in US Pat. No. 5,589,082. FIG. 5 is a cross-sectional view showing a conventional micro movable device. This microphone opening movable device produces a sealing structure for sealing the micro movable portion as described below. That is, the first silicon nitride film 55 2 is formed on the silicon substrate 55 so as to cover the micro filter 55 1 as a micro movable portion and the sacrificial film used for manufacturing the micro filter 55 1. Is deposited. From the opening 553 provided in the silicon nitride film 552, the silicon oxide film serving as the sacrificial film is etched and removed with a diluted hydrofluoric acid solution to form a cavity portion 555. Then, a second silicon nitride film 554 is deposited on the first silicon nitride film 552 by a CVD method, and the opening 553 is closed to complete a sealing structure.

Here, the resonance frequency of the micro movable part strongly depends on the pressure of the cavity in the sealing structure in which the micro movable part is arranged (for example, Ref. 1: YT Cheng et al. et al.), Proceedings of MEMS Conf., 2001, pi 8). Therefore, in the microphone opening movable device of FIG. 5, it is necessary to reduce the pressure of the cavity portion 555 where the microfilter 551 is located to about 3 OmTorr.

In this microphone opening movable device, the entire microfinoleta 551 is sealed with a sealing structure including the first silicon nitride film 552 and the second silicon nitride film 554. They are collectively covered to form a relatively large cavity 555. Therefore, in order to maintain the pressure in the relatively large hollow portion 555, the sealing structure is required to have relatively high strength. If the strength is insufficient, the sealing structure is deformed due to a pressure difference between the inside of the hollow portion 5.55 and the outside of the sealing structure, and the durability is reduced. However, when the thickness of the first and second silicon nitride films 55 2 and 55 4 is increased in order to increase the strength of the sealing structure, the internal stress of these films increases, In some cases, the sealing structure is deformed and durability is reduced. As described above, the conventional micro movable device has a problem that it is extremely difficult to ensure the durability of the sealing structure.

Reference 1 discloses a technique for sealing a micro movable portion by bonding glass substrates. An apparatus for bonding glass substrates under a force vacuum is a general LSI (large-scale integrated circuit). It is not used for the manufacturing process of the circuit, and its introduction requires a large capital investment. In addition, the vacuum sealing technology by bonding the glass substrates may cause a problem of impurity contamination.

As described above, the conventional microphone opening movable device has problems such as an increase in cost and a decrease in durability, particularly when considering the incorporation into an integrated circuit. Disclosure of the invention

Accordingly, the present invention has been made to solve the problems of the above-mentioned conventional micro movable device, and has a micro movable device having a microphone opening movable portion that can be threaded as a part of an integrated circuit on a substrate. An object of the present invention is to provide a micro movable device which can be manufactured at low cost and has good durability.

A micro movable device according to the present invention comprises: a substrate; a single-layer or multi-layer micro-synthesis member that is provided on the substrate and defines a plurality of micro cells; and a non-minimum micro among the plurality of micro cells. A microphone opening movable section disposed in the cell. The sealing structure of the micro movable portion is formed by the one or more layers of the micro cell forming member. Since the microcell forming member has a structure that defines a plurality of microcells, the microcell forming member is formed using a member having a relatively small thickness, and can prevent uneven concentration of stress. Therefore, a sealing structure that is difficult to deform Therefore, a micro movable device having good durability can be obtained.

In one embodiment, the microphone opening cell in which the microphone opening movable section is arranged is the largest microcell among the plurality of microcells. Therefore, the relatively large micro movable portion can be sealed.

In one embodiment of the present invention, the microphone cell in which the micro movable section is arranged is at least twice as large as the micro cell in which the micro movable section is not arranged. The micro cell in which the micro movable portion is arranged can be formed by, for example, removing a portion of a micro cell forming member between two or more adjacent micro cells. Therefore, a microcell having an appropriate size can be easily formed according to the size of the micro movable portion to be sealed.

-The microphone opening movable device of the embodiment is provided in the microphone opening cell forming member and has a communication hole for connecting the microcells to each other. By using this communication hole, it is possible to obtain a relatively short path and a plurality of paths for discharging the sacrificial film and the like used for manufacturing each of the microcells and the microphone opening movable section. Therefore, the removal efficiency of the sacrificial film and the like can be improved.

In the microphone opening movable device of the embodiment, a discharge hole communicating with the microcell is opened on the upper surface of the microphone opening cell forming member in the uppermost layer. Therefore, an upward path for discharging the sacrificial film or the like to the outside can be obtained directly or through a plurality of microcells from the microcell where the micro movable portion is located. Further, by providing a plurality of the discharge holes, a plurality of paths for discharging the sacrificial film and the like from the microphone opening cell where the microphone opening movable portion is located can be formed. Therefore, the sacrificial film and the like can be discharged more efficiently than when one discharge port is provided at each end of the sealing structure as in the conventional microphone port movable device.

In one embodiment, at least one of the plurality of microphone opening cells is filled with a filling member. Therefore, it is possible to form a sealing structure having greater strength than only the microcell forming member. When the sacrificial film used for forming the microcell is used as a filling member, it is not necessary to remove the sacrificial film. Therefore, when, for example, an eyebrow insulating film or the like is provided between the plurality of microsynthesized components, the interlayer insulating film is used as an etcher for removing the sacrificial film. No damage is caused by the device. Furthermore, even when the sacrificial film is made of a material having high hygroscopicity, the sacrificial film is discharged to the outside of the microcell forming member because the sacrificial film remains filled in the microphone opening cell. At this time, no sacrificial film remains in the microcell that should be hollow. Therefore, when the microcell in which the micro movable portion is located is sealed, gas is not released due to the remaining sacrificial film. This can improve the reliability of the micro movable device. In addition, by leaving the sacrificial film, which does not need to be removed, of the plurality of microcells filled as a filling member, the labor for removing the sacrificial film can be reduced, and the manufacturing process of the micro movable device can be simplified.

In one embodiment of the present invention, the microphone opening member has a wall portion and a ceiling portion, and the wall portion and the ceiling portion are electrically connected. By setting the potential of the ceiling to O V, the wall can be set to O V. Therefore, when the micro movable part is a filter or the like and an AC (alternating current) signal is input, noise can be reduced. In addition, by electrically separating a part of the ceiling of the microcell forming member from other parts, a local wiring is formed between the part of the ceiling and the wall electrically connected to the part. Alternatively, a through electrode can be formed.

In one embodiment of the present invention, the uppermost micro cell forming member is electrically insulated from the lower micro cell forming member. Therefore, the microcell forming member below the lowermost layer can be electrically disconnected from the outside. The uppermost microcell forming member can be used as a wiring layer.

In one embodiment of the micro movable device, the micro cell forming member has a wall and a ceiling integrally formed. Therefore, the microcell forming member can be formed by a simple process. In addition, since the strength of the micro cell forming member is relatively large, the micro movable portion in the micro cell can be effectively sealed. In the microphone opening movable device according to one embodiment, the microcell arranged around the microphone opening cell in which the microphone opening movable section is arranged is not filled with a filling member and is hollow. Thereby, it is possible to communicate between the micro cell on which the micro movable portion is arranged and a desired micro cell among the surrounding micro cells. Accordingly, a desired sacrificial film or the like is formed from the microcell in which the micro movable portion is disposed. Since the liquid can be discharged in the direction, the sacrificial film and the like can be reliably discharged from the microcell.

In the microphone opening movable device of one embodiment, the microcell above the microphone opening cell in which the microphone opening movable portion is arranged is not filled with a filling member and is hollow. Therefore, the micro cell in which the micro movable portion is arranged can communicate with the micro cell on the upper side of the micro cell. Therefore, the micro movable portion is relatively large having a dimension of, for example, 100 μππ or more, and has a complicated shape, and is relatively large for disposing the microphone opening movable portion. Even when a microcell having a complicated shape is formed, a sacrificial film or the like can be effectively discharged from the microcell.

In the microphone opening movable device of one embodiment, a microcell arranged around the microphone opening cell in which the microphone opening movable section is arranged is filled with a filling member. Therefore, the strength around the microcell in which the microphone opening movable section is arranged can be increased. Therefore, the micro movable portion can be sealed with good reliability and durability.

In one embodiment, the micro cell arranged around the hollow micro cell is filled with a filling member. Therefore, the strength of the portion around the hollow microcell of the microcell forming member defining the hollow microcell can be improved, and the reliability and durability of the sealing structure can be improved.

-In the micro movable device of the embodiment, the filling member is made of a material having a smaller coefficient of thermal expansion than a material of the micro cell forming member. Therefore, even when the temperature of the micro movable device changes, the influence of the thermal expansion and thermal contraction of the filling member on the micro cell forming member is reduced, so that the microphone opening movable portion has good reliability and durability. Can be sealed.

In the microphone opening movable device of one embodiment, the plurality of microcell forming members separated from each other are located at the same level. Therefore, it is possible to prevent the stress concentration to each microcell shaped forming member, it is possible to improve the reliability ■ durable I ¹ production of the micro-cell member.

In one embodiment of the present invention, the movable part of the microphone is characterized in that the movable part of the microphone is nitrided of a high melting point metal. It is composed of materials containing objects. Therefore, the micro movable portion can be formed not only on a substrate made of Si (silicon) but also on a substrate made of a material having a melting point higher than that of Si.

In one embodiment, the micro cell forming member is made of a material containing a nitride of a high melting point metal. Therefore, the microcell forming member can be formed not only on a substrate having Si force but also on a substrate made of a material having a melting point higher than Si.

In the microphone opening movable device of one embodiment, the microphone opening movable portion is formed of two or more layers having different internal residual stresses. Therefore, by adjusting the working direction and the magnitude of the internal residual stress of each of the layers, the residual stress in the 內 portion when the entire micro movable portion is considered can be reduced.

In one embodiment, the microcell forming member is formed of two or more layers having different internal residual stresses. Therefore, by adjusting the action direction and the magnitude of the internal residual stress of each of the layers, the internal residual stress when the entire microcell forming member is considered can be reduced.

In one embodiment, the microphone opening movable section includes a layer made of a high melting point metal and a layer made of the nitride. Therefore, the electrical conductivity of the micro movable portion can be increased, the potential of the microphone opening movable portion can be accurately controlled, and the internal residual stress of the micro movable portion can be reduced.

—In the micro movable device according to the embodiment, the microceno component includes a layer made of a high melting point metal and a layer made of the nitride. Therefore, the electric conductivity of the microcell forming member can be increased, the potential of the microphone cell forming member can be accurately controlled, and the internal residual stress of the microcell forming member can be reduced. In addition, since a part of the microcell forming member can be used as a wiring or a penetrating electrode, a space for the wiring can be reduced, and the size can be reduced. Can be simplified and the cost can be reduced. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan sectional view showing a part of a microphone opening movable device according to a first embodiment of the present invention. You.

FIG. 2 is a longitudinal sectional view showing a part of the micro movable device according to the first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a part of the micro movable device according to the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a part of the micro movable device according to the first embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a conventional micro movable device.

FIG. 6 is a plan sectional view showing a micro movable device according to a second embodiment of the present invention. FIG. 7A is a longitudinal sectional view taken along line AB in FIG. 6, and FIG. 7B is a longitudinal sectional view taken along line AC in FIG.

FIG. 8A is a longitudinal sectional view showing a part of the uppermost layer microcell forming member provided in the micro movable device of the present invention, and FIG. 8B is a longitudinal section showing a modification of the uppermost microphone opening cell forming member. FIG.

FIG. 9 is a perspective view showing a state where the micro cell forming member provided in the micro movable device of the present invention is cut along a plane parallel to the plane of the substrate. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First Embodiment)

FIG. 1 is a plan cross-sectional view showing a part of a microphone opening movable device according to a first embodiment of the present invention, and shows a state in which a portion where a microcell is formed is cut along a plane parallel to a plane of a substrate. ing. FIG. 2 is a vertical cross-sectional view showing a part of the micro movable device of the first embodiment, and shows a state where a part where a micro cell is formed is cut in a direction perpendicular to a plane of a substrate.

This micro movable device is provided with a single or multi-layered micro cell forming member 22, 23, 24 formed on the substrate 20. Microcells 11, 12, 13 are defined. The microcells 11, 12, and 13 are cut parallel to the plane of the substrate as shown in FIG. The surface is partitioned by the wall 10 of the microcell forming member. The microcell is formed to have dimensions such that the width and length are within predetermined ranges.

The substrate 20 is a silicon substrate, and the microphone opening cell forming members 22, 23, 24 are formed of polysilicon doped with impurities.

In the micro movable device of the present embodiment, the thickness of the wall portion of the microcell forming member 22 of the first layer closest to the substrate 20 is formed to be 1.5 to 2 / im. The second- and third-layer microcell forming members 23 and 24 formed on the first-layer microcell forming member 22 have a wall thickness of 2-3 μm. Is formed. The height of each of the above-mentioned walls is preferably formed to be substantially the same as the thickness of the walls in consideration of strength. Therefore, the height of the wall, that is, the height from the bottom to the ceiling of the microcell is set to 2 μιη for the first layer and 3 μιη for the second and third layers. In order to seal the micro movable portion on the substrate at low cost and compactly, it is preferable that the thickness of the sealing structure is small. However, the inside and outside of the sealing structure when the microphone opening movable portion is vacuum-sealed is preferably used. It must be able to withstand the deflection caused by the pressure difference and the stress generated by this deflection. Here, in order to vacuum seal a square region having a side of 200 / Xm on the substrate, a conventional sealing structure having a film as shown in FIG. An experiment was conducted to measure the bending and stress generated in each sealing structure in the case where the sealing structure including the light microcell forming member was used. Regarding the sealing structure using the microcell forming member of the present invention, a microcellular member having four square microcells each having a side of about 100 m on a plane is used, Experiments were conducted on a case where a microcell forming member having nine square microcells each having a side of about 67 μm was used.

From this experimental result, the maximum bending amount can be reduced to a value of about 6% according to the sealing structure using the microcell forming member having four microcells as compared with the sealing structure using the conventional membrane. It was also found that the maximum stress could be reduced to about 22%. Furthermore, according to the sealing structure using the micro-ceno forming member having nine microcells, the maximum radius can be reduced to 1% or less as compared with the sealing structure using the conventional membrane. However, it was found that the maximum stress can be reduced to a value of 10% or less. Therefore, a sealing structure is formed using the microcell forming member of the present invention, By forming the microcell defined by the microcell forming member of the above in a plane having a width and a length within a range of less than 10 μm, the maximum deflection amount of the sealing structure can be reduced to 0.01 μm. The stress concentration can be reduced to πι or less, and the vacuum sealing can be performed using a thin film of several microns.

Here, the width in the plane of the microcell is preferably about 3 to 5 times or less the thickness of the wall, specifically, 10 μm or less. The smaller the width of the microcell is, the more the bending of the sealing structure can be suppressed and the stress can be reduced. On the other hand, the length in the plane of the microcell may be several 100 μπι if the width of the microcell is set within a predetermined range. As described above, by using the microcell forming member that defines the microcell having a predetermined dimension, even when the movable portion of the microphone opening on the substrate is vacuum-sealed, the bending and the concentration of stress are reduced, and the A sealing structure capable of withstanding a pressure difference can be formed.

Further, in the microcell forming member, it is not necessary that all the microcells are hollow microcells in which a filling member or the like is not filled. Therefore, a sealing structure can be formed with one or more microcells being kept filled with the sacrificial film used when the microcells were formed. Therefore, the labor for removing the sacrificial film can be reduced.

In addition, since the micro movable portion uses a film thicker than that used in a normal LSI process, non-uniform stress and stress concentration are likely to occur on the substrate on which the micro movable portion is formed. However, by disposing the microphone opening cell forming member around the micro movable portion on the substrate, a sealing structure fixed to the substrate over a relatively wide area can be formed. Therefore, it is possible to prevent the occurrence of uneven stress and the occurrence of localized stress in the substrate, thereby improving the reliability and durability of the sealing. Further, since the microcell forming member is fixed to the substrate over a wider area than before, no warping or steps occur on the substrate. Therefore, the micro movable portion and the sealing structure can be formed while maintaining the flatness of the substrate. In the above embodiment, the force using a rectangular microcell in the plane is not limited to this, but may be a polygon such as a regular hexagon. Further, preferably, communication holes 14, 27, and 28 are formed as necessary in the wall and ceiling of the microcell forming member that separates the hollow microcells. For example, as shown in FIG. 1, adjacent hollow microcells communicate with each other through communication holes 14 formed in the wall 10 as shown by arrows 15. Also, as shown in FIG. 2, through a communication hole 28 formed in the wall of the microcell forming member 24 in the uppermost layer, as shown by an arrow 29, a hollow microcell adjacent to the same level is formed. Cells are communicated with each other.

Thereby, when discharging the sacrificial film in each microcell to the outside of the microcell forming member, a plurality of paths can be secured. Therefore, the shortest discharge path can be obtained for the sacrificial film of each microcell, and the sacrificial film can be dispersed and discharged in a plurality of paths. Therefore, the removal efficiency of the sacrificial film can be improved. Further, preferably, a plurality of discharge holes 30 communicating with the microcells to be hollowed are provided in the ceiling of the uppermost microcell forming member. Thus, when the hollow microcell is formed, the sacrificial film at the microcell portion can be quickly discharged upward. Further, when the sacrificial film is discharged from the microcell in the microcell forming member below the uppermost layer, a plurality of discharge paths can be formed from the central portion of the microcell. Therefore, it is possible to discharge the sacrificial film more efficiently than discharging the sacrificial film only from the end of the sealing film as in the conventional sealing structure. Usually, the micro movable portion used in the MEMS has a size of several 10 to several 1 O O / m in the plane of the substrate. Therefore, if the sacrificial film in the sealing structure that covers the micro movable portion is to be removed from the horizontal end of the substrate of the sealing structure as in the related art, the length of the removal path of the sacrificial film significantly increases. The efficiency of removing the sacrificial film is very low. On the other hand, the sealing structure of the present embodiment has a structure in which a plurality of communication ports are provided in the ceiling portion of each microcell forming member so that the microcells 25 above the lowermost layer as shown by arrows 31 in FIG. The sacrificial film can be removed. Accordingly, a relatively short removal path having a length substantially equal to about 10 μΐη, which is the dimension in the thickness direction of the sealing structure, can be obtained, so that the sacrificial film can be quickly discharged.

More preferably, in a microcell in which a filling member is filled, the filling member is completely covered with a surface of a ceiling, a wall, and a floor of the microcell forming member. It is not exposed outside this microcell. For example, in the present embodiment, the microcell 26 in FIG. 2 is filled with a sacrificial film, and the sacrificial film is completely covered with the microcell component 22 that defines the microcell 26. Therefore, the strength of the sealing structure can be increased by the sacrificial film, and the deterioration of the microcell forming member 22 due to the etchant for removing the sacrificial film can be reduced. When an interlayer insulating film is formed between the microphone opening cell forming members 22, 23, 24, damage to the interlayer insulating film from the etchant can be reduced.

Further, in this embodiment, a silicon oxide film having relatively high hygroscopicity is used as the sacrificial film. However, since the silicon oxide film is not exposed to the hollow microcell in which the micro movable portion is disposed, gas release after sealing the movable portion of the microphone can be suppressed, and the reliability of the sealing is improved. it can. Further, since it is not necessary to remove all the sacrificial films in the sealing structure, the removal efficiency of the sacrificial films can be improved. More preferably, the wall and the ceiling of the microcell forming member are electrically connected to each other. For example, in FIG. 3, which shows the vicinity of the microcell 44 in which the micro movable portion 41 is arranged, the wall portion 431 and the ceiling portion 432 of the lowermost microcell forming member 43 are electrically connected to each other. And the wall portion 48 1 of the second-layer microcell forming member 48 and the ceiling portion 48 2 are electrically connected. Then, the wall portion 43 1 of the lowermost micro cell forming member 43 is connected to the electrode 40. In addition, the ceiling portion 43 of the lowermost microphone opening cell forming member 43 and the wall portion 481 of the second microphone opening cell forming member 48 are electrically connected. Thereby, the potential of the inner surface of the micro cell 44 on which the micro movable portion 41 is arranged can be kept at OV. Accordingly, when the micro movable section 41 is a filter, an AC signal is often input to the filter, so that noise can be reduced. In each of the sealing structures shown in FIGS. 1, 2, 3 and 4, a predetermined wall portion and a ceiling portion of each microcell forming member 22, 23, 24, 43, 48, 49 are required. By electrically disconnecting and connecting to other parts, local wiring and through electrodes can be formed. More preferably, the uppermost layer of the microcell forming member is electrically insulated from the lower microcell forming member. In the present embodiment, the microphone opening cell is formed. The uppermost layers 24, 49 of the members are made of a silicon nitride film, so that they are electrically insulated from the respective microcell forming members 23, 48 below. As a result, the sealing structure can be electrically shielded from the outside, and a wiring layer can be formed on the uppermost layers 24 and 49 of the microcell forming member.

More preferably, the microcell forming members 22, 23, 24, 43, 48,

49 The wall and ceiling are integrally formed. By integrally forming the wall and the ceiling, the manufacturing process of the microcell forming members 22, 23, 24, 43, 48 and 49 can be simplified. The sealing performance of the micro movable section 41 by the sealing structure using the members 22, 23, 24, 43, 48, 49 can be improved.

The micro movable portion shown in the cross-sectional views of FIGS. 3 and 4 is a Beam type micro filter 41. The microfilter 41 is formed so as to vibrate by a signal from the input electrode 42 formed downward. The microfilter 41 is formed by the same process as the microcell forming member of the first layer. Accordingly, the substrate 20 has a step, a warp, and the like between a portion where the microfilter 41 is formed and a portion where the microcell forming member 43 around the microfilter 41 is formed. The flatness is maintained without occurrence of cracks.

The microcell 44 on which the microfilter 41 is arranged is defined by a first-layer microcell forming member 43 and a second-layer microcell member 48. Therefore, the second-layer microcell forming member 48 can maintain the flatness without any step or warpage.

The sealing structure of the present invention is not limited to the beam type microfilter 41, but can be applied to a filter having a complicated shape such as a comb type or a tuning fork type. Due to the structure, the necessary minimum number of microcells according to the shape of the micro movable portion can be easily formed only around the micro movable portion.

Further, preferably, at least one hollow microcell 46 is disposed above the microcell 44 in which the microfilter 41 is located. That is, a third-layer microcell defining a hollow microcell is placed on a second-layer microcell forming member 48 defining a microphone opening cell in which the microfilter 41 is located. At least one layer of the cell forming member 49 is formed. As a result, a communication hole 47 is provided in the ceiling of the second layer of the micro-senore forming member 48, and the communication hole 47 in the ceiling allows the sacrifice in the microcell 44 where the microfilter 41 is located. The membrane can be quickly discharged to the upper hollow microcell 46, and the sacrificial membrane can be quickly discharged from the hollow microcell 46 to the outside of the sealing structure through the discharge hole. By closing the discharge hole of the third-layer microcell forming member 49 with the cap film 491, the microfilter 41 can be easily and reliably sealed. In this case, the third-layer microcell forming member 49 defining the hollow microcell is not provided, and the communication hole 47 of the second-layer microcell forming member 48 is formed as the discharge hole of the sacrificial film. If used, the inconvenience that the material of the cap film is deposited on the microfilter 41 when the cap film closing the discharge hole is deposited. Further, preferably, a hollow microcell 45 is arranged around the microcell 44 in which the microfilter 41 is located. For example, only the communication hole 47 located at the center of the microcell 44 can be formed on the ceiling of the microcell forming member 48 defining the microcello 44 where the microfilter 41 is located, If the communication hole located at the end of the microcell 44 cannot be provided, an etchant for removing the sacrificial film remains at the end of the microcell 44 or the sacrificial film is not removed. May remain. Therefore, by arranging a hollow microcell 45 around the microcell 44 where the microfilter 41 is located, the microfilter 4 is passed through the hollow microcell 45.

The etching liquid and the sacrificial film can be reliably removed from the end of the microcell 44 where 1 is located.

Preferably, microcells 53, 54 filled with a filling member are arranged around the hollow microcells 45, 46. Thus, the first microcell forming member 43 defining the hollow microcells 45 and 46 and the microcellular forming member 49 of the uppermost layer around the hollow microcells 45 and 46 of the uppermost microcellular forming member 49 are formed. The strength of the part can be improved. Therefore, the reliability and durability of the sealing structure using the microcell forming members 43 and 49 can be improved.

(Second embodiment) FIG. 6 is a diagram illustrating a micro movable device according to a second embodiment of the present invention. In this micro movable device, a tuning fork resonator 101 as a micro movable portion having a size exceeding 10 in the plane of the substrate and having a complicated shape is sealed.

FIG. 6 is a cross-sectional plan view showing a state cut along a plane parallel to the substrate at a position corresponding to the wall of the microcell forming member of the second layer from the substrate side. FIG. 7A is a longitudinal sectional view taken along line AB in FIG. 6, and FIG. 7B is a longitudinal sectional view taken along line AC in FIG.

The sealing structure 100 of the microphone opening movable device includes three layers of micro-senor forming members 13 1, 13 2, and 13 3 formed on the substrate 130. The three-layer microcell forming members 1311, 1332, and 1333 define a hollow microcell 112 and a microcell 113 filled with a filling member. The hollow microcell 105 in which the resonator 101 as the micro movable portion is located is composed of a first-layer microcell forming member 131, and a second-layer microphone opening cell forming member 132 It is defined as Since the resonator 101 has a dimension exceeding 100 / m, the distance between the walls defining the microcell 105 is very long. However, in the present embodiment, by arranging the microcells 112 and 113 according to the shape of the resonator 101, the microcells 105 in which the resonator 101 is arranged The size is minimized. Further, the anchor portion 104, which is a non-movable portion of the resonator 101, is a microcell defined by the first to third microcell forming members 13 1, 13 2, and 13 3 respectively. It is formed by filling a microcell with a filler at the same position on a plane. Further, the column 106 is provided at a position where the operation of the movable portion of the resonator 101 is not hindered and the potential of the movable portion is not substantially affected.

Since the potential of the portion of the resonator adjacent to the column 106 is determined by the electrode 107 connected to the anchor portion 104, the column 106 is set to the same potential as the electrode 107. By doing so, it is possible to reduce the influence on the above-mentioned resonator portion.

Further, as shown in FIG. 7A, a hollow microcell 135 is arranged on the microcell 105 where the resonator 101 is located. This hollow microcell 1 3 According to 5, the sacrificial film in the microcell 105 where the resonator 101 is located can be quickly removed upward of the microcell 105 when the sealing structure is manufactured. The ceiling of the second-layer microphone opening senor forming member 132 is reinforced by the uppermost microcell forming member 133 that defines the hollow microcell 135, and the ceiling is formed. And the local concentration of the stress can be prevented. Therefore, the maximum amount of radius can be set to 0.01 jum or less, even though the interval between the wall portions defining the microcell 105 exceeds 100 μπι.

As described above, according to the present embodiment, the use of the microcell forming members 13 1, 13 2, and 13 3 allows the tuning fork resonator 101 to have a large and complicated shape. However, it is possible to form a sealing structure having a shape corresponding to the shape of the resonator 101, having relatively high strength and excellent durability.

Further, in the present embodiment, there is provided means for alleviating expansion and contraction of the sealing structure due to a temperature change or the like. As shown in FIG. 7, this means is a cut 120 formed in the ceiling of the microcell forming member 133 of the uppermost layer. FIG. 8A is an enlarged schematic cross-sectional view showing the vicinity of the portion where the cut 120 is formed. This notch 120 is formed in the ceiling other than the portion where the microcell 122 connected to the microcell 105 where the resonator 101 is located and the communication hole 124 is located. ing. Through the notch 120, a wall portion 141 defining the microcell 122, which is in communication with the microphone opening cell 105, in which the resonator 101 is located, outside the micro movable device. Facing

For example, when the temperature of a part of the uppermost microcell forming member 133 changes, the force generated by thermal expansion or thermal contraction is transmitted to the other part of the microcell forming member 133. Prevented by 120. Therefore, concentration of stress on the connection portion between the sealing structure including the uppermost microcell structure member 133 and the substrate 130 can be reduced, and the durability and reliability of the sealing can be improved. In the conventional sealing structure of FIG. 5, the stress caused by the difference in the coefficient of thermal expansion between the substrate 550 and the sealing films 552, 554 is caused by the stress generated by the substrate 550 and the sealing films 552, 5 5 Concentrated near the connection with 4 and a large stress is generated in this part, which causes deterioration and destruction of the sealing structure It was. The same applies to a case where an impact is applied to the substrate 550 or a case where the substrate 550 is deformed such as a warp.

However, in the present embodiment, transmission of force from the sealing structure to the substrate 130 and transmission of force from the substrate 130 to the sealing structure are cut off by the cut 120. Therefore, the concentration of the force on the end of the sealing structure and the concentration of the force on the connecting portion between the first-layer micro-synthesized component 13 1 and the substrate 130 are alleviated. As a result, deterioration and destruction of the sealing structure due to stress concentration can be prevented, and the durability of the sealing structure can be improved.

The cut 120 may be formed as shown in FIG. 8B. That is, an extended portion 140 extending from the lower end of the wall of the uppermost microcell forming member 133 toward the inside of the cut 120 is provided, and this extended portion 140 is attached to the microcell forming member 1 of the second layer. Fix it to the top of 32 ceiling. As a result, the wall portion of the uppermost layer of the microporous member 133 can be firmly fixed to the upper surface of the ceiling portion of the second-layer microcell forming member 132 without any gap. Therefore, the microcell 122 communicating with the microcell 105 in which the resonator 101 is located can be reliably sealed to the outside, so that the reliability of the sealing structure can be improved.

The cuts 120 may be provided at the same level, for example, on the uppermost layer so that a plurality of microcell forming members 133a, 133b, and 133c are separated from each other. That is, as shown in FIG. 7A, a plurality of microcell forming members 133a, 133b, 133c are formed in the uppermost layer, and the plurality of microcell forming members 133a, 133 are formed. b, 133 c are separated by the notch 120. Thus, transmission of force from one of the plurality of microcell forming members to the other is reliably prevented.

The cut 120 may be partially provided on the ceiling of the same microphone opening cell forming member. The cuts 120 are not limited to the uppermost layer, and may be formed in the microphone opening cell forming members 13 1 and 13 2 of the first layer or the second layer. FIG. 9 is a perspective view showing a state where the uppermost microcell forming member 133 is cut at a position of a wall portion of the microseno forming member 133 by a plane parallel to the plane of the substrate 130. As shown in Fig. 9, the microcell at the second eyebrow and the top layer A large number of communication holes are provided on the ceiling of the second-layer microcell forming member. Also, a plurality of communication holes communicating between the adjacent hollow microcells in the uppermost layer are provided in the wall of the microcell forming member in the uppermost layer. Due to the plurality of communication holes 151, the wall has a shape like pillars. In addition, a communication hole 153 communicating between the microcells filled with the filling members adjacent to each other in the uppermost layer is provided in the wall of the microseno component member in the uppermost layer. A plurality of communication holes 153 may be provided. The shapes of the communication holes 150, 151, 153 are not limited to those shown in FIG.

Due to the large number of communication holes 150 and 151, the efficiency of discharging the sacrificial film to the outside when forming a hollow microcell can be improved. In addition, by providing the above-mentioned large number of communication holes 150, 151, and 153, stress generated by thermal expansion or thermal contraction, or impact force or warpage of the substrate 130 can be easily dispersed. it can. In addition, by providing a cutout 152 in the ceiling of the microseno-forming member so as to communicate between adjacent hollow microcells, stress concentration can be prevented. In addition, by providing a notch (not shown) in the ceiling of the microcell forming member so that the adjacent microcells communicate with the filled microcells, stress concentration can be prevented. In this way, the durability of the sealing structure formed using the microcell forming members 13 1, 13 2, and 13 3 can be improved. Further, in the present embodiment, the microcell 105 in which the resonator 101 is located and the microcell adjacent to the microcell 105 are formed in a hollow shape. The microcell is also hollow. For example, as shown in FIG. 6, a plurality of hollow microcells 115 that are not connected to the microcell 105 where the resonator 101 is located are placed on the plane of the sealing structure 100. It is provided in the vicinity of the corner. The plurality of hollow microcells 115 communicate with each other through communication holes. As described above, by providing the hollow microcell 115 that does not communicate with the microcell 105 in which the micro movable portion is arranged, it is possible to prevent the stress from being generated unevenly in the sealing structure 100, The stress can be evenly distributed throughout the sealing structure 100, and the reliability and durability of the sealing structure 100 can be improved.

In the present embodiment, the sealing structure 100 is used when forming a microcell. A microcell 113 filled as a filling member without discharging the silicon oxide as a sacrificial film. Since the microcell 113 is filled with the filling member, the strength of the sealing structure 100 can be increased as compared with the case where only the microcell forming member is used. The coefficient of thermal expansion of the silicon oxide is about 0.5 ppm / ^ C, and the coefficient of thermal expansion of silicon-silicon nitride forming the microcell forming members 131, 132, 133 (2.5 ppm / ° C). Degree). Therefore, the combined portion of the microcell 113 filled with the silicon oxide and the microcell forming member defining the microcell 113 is larger than the portion including only the microcell forming member defining the hollow microcell. The stress generated when a temperature change occurs is reduced. Thus, by providing the microcell filled with silicon oxide as the filling member, the strength can be increased and the stress due to thermal expansion and thermal contraction can be reduced. Therefore, by dispersing the microcells filled with the silicon oxide in the sealing structure 100, it is possible to effectively concentrate the stress due to thermal expansion and thermal contraction at a predetermined position of the sealing structure 100. Can be prevented. In addition, as shown in Fig. 6, around the microcell 105 where the resonator 101 is located, and around the hollow microcell 109 communicating with the microcell 105. A microphone port cell filled with the above filling member is arranged. By doing so, the reliability and durability of the sealing function of the microphone opening Senole 105 can be improved.

In the above embodiment, the sealing structure 100 is formed by using the three-layer microphone opening cell forming members 131: 132, 133. However, the number of the microcell forming members forming the sealing structure is not limited to three layers, Any number of layers above the layer may be used.

(Third embodiment)

The microphone opening movable device according to the third embodiment of the present invention is the same as the micro movable device according to the first and second embodiments, except that the microcell forming members 22, 23, 24, 43, 48, 49, 131, 132, 133 As a material, tungsten nitride is used instead of silicon / silicon nitride. Tungsten nitride can be formed by a reactive sputtering method. For example, sputtering pressure 2.3 Pa, RF (high frequency oscillation) power 300 W, Ar (anoregon) gas flow rate 33.6 sccm, N ₂ (nitrogen ) Gas flow rate 8.4 sccm _s Substrate temperature 25 ° C Nsten can be formed. In other words, it is possible to form a microceno-composed member at a significantly lower temperature than when silicon / silicon nitride formed using an LPCVD method having a relatively high process temperature is used as a material for a microphone-opened cenocomposed member. Therefore, according to the present embodiment, for example, CMOS (complementary metal oxide semiconductor:

Compatible Metal-Oxide Semiconductor) process has low heat resistance, such as silicon substrate on which LSI is fabricated, glass substrate or resin substrate on which Cu (copper) wiring and low dielectric constant organic insulating film are formed. A sealing structure using a microcell forming member can also be formed on a substrate on which elements are formed.

Further, in the micro movable device according to the first and second embodiments, the micro movable portions 41 and 101 are combined with the micro cell forming members 22, 23, 24, 43, 48, 49, and

It is preferable to use tungsten nitride as in the case of the materials 131, 132, and 133. Thus, the production of the micro movable portions 41 and 101 and the production of the sealing structure using the micro cell forming members 22, 23, 24, 43, 48, 49, 131, 132 and 133 are relatively low. It can be performed in common steps under process temperature. Therefore, on a silicon substrate on which an LSI is fabricated by a CMOS process, or on a substrate on which low heat-resistant elements are formed, such as a glass substrate or a resin substrate on which Cu wiring or an organic insulating film with a low dielectric constant is formed. In addition, the micro movable portion and the sealing structure can be formed with little effort.

Here, for example, when the above-mentioned micro cell forming member 可動 micro movable portion is formed using a single metal material such as tungsten, there are the following disadvantages. In other words, due to the influence of the crystal structure oriented in the growth direction of the material and the difficulty in controlling the grain growth as the film thickness increases, internal stress accumulates during the deposition of tungsten, or during deposition or deposition of tungsten. Later, destruction such as film peeling may occur. In addition, when a load such as stress acts on a member formed by depositing tungsten, defects such as cracking are generated, and deformation and calculus are generated. Therefore, it is difficult to ensure the reliability and durability of the microcell forming member / microphone opening movable portion formed using a single metal material such as the above-mentioned tungsten.

When the movable part of the microphone opening is formed of silicon, the internal residual stress can be obtained by annealing at about 1000 ° C for about 1 hour after silicon deposition. Can be alleviated. However, if the microseno component ゃ microphone opening movable part is formed of a single metal such as tungsten, if the internal stress is reduced by recrystallization by high temperature treatment, coagulation 形状 changes in shape such as faceting Problems often arise.

Here, by using tungsten nitride as the material of the microcell forming members 22, 23, 24, 43, 48, 49, 131, 132, 133 and the micro movable parts 41, 101, the internal stress is reduced. Can solve the problem of accumulation of defects and the occurrence of defects. That is, when the shape forming the tungsten nitride by reactive sputtering, under the low temperature of about room temperature, by changing the conditions such as N ₂ partial pressure Ya sputtering pressure, it can be easily changed the composition and properties of the tungsten nitride. For example, by changing the sputtering pressure in the range of about 1.5 Pa to 3 Pa, the type of residual stress in the formed tungsten nitride film can be changed from tensile stress to compressive stress. it can. Therefore, in the process of forming tungsten nitride, it is possible to grow by continuously or intermittently changing the internal stress and composition, thereby almost eliminating the internal stress during deposition and the residual stress after deposition. be able to. In addition, since it is possible to form a tungsten nitride film having a different composition and grain state in the thickness direction, it is possible to avoid rupture due to internal stress, for example, by forming adjacent compositions that generate stresses in opposite directions. can do. Also, by making the composition different in the thickness direction of the tungsten nitride film, even if a stress or the like is applied from the outside after the film is formed and a defect is partially generated, the defect hardly penetrates the entire film. be able to. Therefore, the resistance to deformation and breakage due to cracking can be increased. Such a tungsten nitride film is formed, for example, under the following conditions. First, under the conditions of sputtering pressure 2. OP a, RF power 300 W, Ar gas flow rate 33.6 sccm, N ₂ gas flow rate 8.4 sccm, and substrate temperature 25 ° C, tungsten nitride was 0.5 μπα. Deposit to thickness. Subsequently, the sputtering pressure was changed to 2.4 Pa, and 1.2 μπι deposition was performed. Finally, the sputtering pressure was returned to 2.0 Pa, and 0.3 μΐη deposition was performed.

Further, by using a film having a tungsten layer at the center in the thickness direction of the tungsten nitride layer, the lowermost microcell forming members 22, 43, 131 and the micro movable portion 4 are formed. It is preferred to form 1,101. Such a film is formed as follows. First, sputtering pressure 2. 3-Way a, RF power 300 W, Ar gas flow rate 33. 6 sc cm, N ₂ gas flow 8. 4 sccm, under the condition of a substrate temperature of 25 ° C, to 1. 2Myuiotaita deposited nitride data tungsten . Then, instead of the New ₂ gas flow rate of 0 on the sccm both Ar gas flow rate of 42 sc cm, to 0. 5Myuiotaita deposit tungsten film nitrogen hardly contain. Finally, the Ar gas flow rate was returned to 33.6 sccm, the N ₂ gas flow rate was returned to 8.4 sccm, the sputtering pressure was 2.0 Pa, and the tungsten nitride film was 0.3 / xm is deposited. The film thus formed can reduce the residual stress and the effective electrical resistance. Therefore, by using this film, the controllability of the potential of the microcell forming member and the movable portion of the microphone opening can be improved. In addition, since a part of the microcell forming member can be used as a wiring or a through electrode, a wiring space can be reduced, and a manufacturing process of a micro movable device can be simplified and cost can be reduced.

In the present embodiment, tungsten is reacted with nitrogen. However, the same effect can be obtained by reacting tungsten with carbon or oxygen without being limited to nitrogen. The same effect can be obtained by using other metals such as tantalum, molybdenum, titanium, nickel, and aluminum. In particular, high melting point metals such as tungsten, tantalum, molybdenum, and titanium, which can provide a high Young's modulus, are preferable. For example, when the Young's modulus of tungsten nitride was measured using an indentation type thin film tester, the Young's modulus was changed from 36 OGP a to 25 OGP by depositing while changing the nitrogen content from 0% to about 60%. It can be changed to a degree. As described above, the nitride of the high melting point metal can obtain a higher Young's modulus than polysilicon ゃ SiGe.

The present invention is not limited to the embodiments described above, and it goes without saying that various changes and additions are possible within the scope shown in the claims.

Claims

The scope of the claims

1. Substrate (20, 130)

It is provided on the substrate (20, 130) and has a plurality of microcells (11, 12, 13, 25, 44, 45, 46, 26, 104, 105, 112, 113,

115, 122, 135) and one or more layers of microcell forming members (22, 23, 24, 43, 48, 49, 131, 132, 133) and a non-minimum microcell of the plurality of microcells. Micro movable parts (41, 101) placed in cells (44, 105)

A micro movable device comprising:

2. The micro movable device according to claim 1,

The microcell (105) in which the microphone opening movable part is arranged is the largest microcell among the plurality of microsores (104, 105, 112, 113, 115, 122, 135). Mic mouth movable device.

3. The micro movable device according to claim 1,

The microcell (105) with the movable part of the microphone opening is twice the size of the microcell (104, 112, 113, 115, 122, 135) without the movable part. A micro movable device characterized by the above.

4. The micro movable device according to claim 1,

The microcell forming member (22, 23, 24, 43, 48, 49, 131, 132, 133) and the communication hole (14, 27, 28, 47, 150, 151, 153).

5. The microphone opening movable device according to claim 1,

The upper surface of the microcell forming member (24) is connected to the microcell. A micro movable device characterized in that the discharge hole (30) through which it passes is open,

6. The micro movable device according to claim 1,

A micro movable device characterized in that at least one (13, 26, 113, 104) of the plurality of micro-sensors is filled with a filling member.

7. The microphone opening movable device according to claim 1,

The microcell forming member (43, 48) has a wall (431, 481) and a ceiling (432, 482), and the wall (431, 481) and the ceiling (432, 482) are electrically connected. A micro movable device, wherein the micro movable device is connected to the micro movable device.

8. The microphone opening movable device according to claim 1,

The micro movable device, wherein the micro cell forming member (24, 49) in the uppermost layer is electrically insulated from the micro cell forming member (23, 48) in the lower layer.

9. The micro movable device according to claim 1,

The micro movable cell forming member (22, 23, 24, 43, 48, 49) has a wall part (431, 481) and a ceiling part (432, 482) formed integrally. apparatus.

10. The micro movable device according to claim 1,

The microcells (45, 46, 122, 135) arranged around the microcells (44, 105) in which the micro movable parts are arranged are characterized in that they are hollow without being filled with a filling member. Micro movable device.

11. The micro movable device according to claim 1,

The microcells (46, 122, 135,) above the microphone port cells (44, 105) in which the above-mentioned microphone port movable parts are arranged are not filled with a filling member and are hollow. A micro movable device, comprising:

1 2. The microphone opening movable device according to claim 1,

A micro movable device characterized in that the micro cell (1 13) arranged around the micro cell (44, 105) in which the micro movable portion is arranged is filled with a filling member.

1 3. The micro movable device according to claim 10, wherein

A micro movable device characterized in that the micro cells (53, 54) arranged around the hollow micro cells (45, 46) are filled with a filling member.

14. The micro movable device according to claim 12,

The micro movable device, wherein the filling member is made of a material having a smaller coefficient of thermal expansion than a material constituting the micro cell forming member (43, 49, 132).

1 5. The micro movable device according to claim 13,

The micro movable device, wherein the filling member is made of a material having a smaller coefficient of thermal expansion than a material of the micro cell forming member (43, 49, 132).

1 6. The microphone opening movable device according to claim 1,

A plurality of the micro cell forming members (133a, 133b, 133c) separated from each other. Force A micro movable device characterized by being located at the same level.

1 7. The micro movable device according to claim 1,

The micro movable device (41, 101) is made of a material containing a nitride of a high melting point metal.

1 8. The microphone opening movable device according to claim 1,

The above microcell forming members (22, 23, 24, 43, 48, 49, 131, 132, 133) are micro movable devices made of a material containing a nitride of a high melting point metal.

19. The micro movable device according to claim 17,

The micro movable device, wherein the micro movable portion (41, 101) is formed of two or more layers having different internal residual stresses.

20. The microphone opening movable device according to claim 18,

A micro movable device characterized in that the microseno component (22, 23, 24, 43, 48, 49, 131, 132, 133) is formed of two or more layers having different internal residual stresses.

21. The microphone opening movable device according to claim 17,

The micro movable device (41, 101), comprising: a layer made of a high melting point metal; and a layer made of the nitride.

22. The micro movable device according to claim 18, wherein

The micro cell forming member (22, 23, 24, 43, 48, 49, 131, 132, 133) includes a layer composed of a high melting point metal and a layer composed of the nitride. apparatus.