JP2012135819A - Mems device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that surely prevents the occurrence of sticking for a long period of time in an MEMS device including a substrate and a movable structure.SOLUTION: The MEMS device includes a substrate and a movable structure. The movable structure has: a movable part arranged above the substrate while being spaced apart at an interval therefrom; a fixed part fixed to the substrate via an insulating film; and each support beam for connecting the movable part and the fixed part to each other. The MEMS device has each first projection, continuously formed from the movable structure, on the lower-surface side of the movable structure. The MEMS device has each second projection, continuously formed from the substrate, on the upper-surface side of the substrate. The MEMS device is configured such that each first projection and each second projection are arranged oppositely to each other while having substantially the same size.

Description

  The present invention relates to a MEMS (Micro Electro Mechanical Systems) device.

  In recent years, a technology for manufacturing a MEMS device having a three-dimensional structure using a semiconductor integrated circuit manufacturing technology has been developed. Various technologies such as a pressure sensor, an acceleration sensor, a gyroscope, an optical deflection device, an RF switch, and a variable capacitor are provided. The device is realized. In order to realize a three-dimensional structure with a semiconductor integrated circuit manufacturing technique, a technique of selectively and locally etching a laminated substrate including a sacrificial layer is used. The MEMS device referred to in this specification is realized by selectively and locally etching a laminated substrate including a sacrificial layer using a semiconductor integrated circuit manufacturing technique represented by a film forming technique and an etching technique. An apparatus having a dimensional structure.

  Some of the above MEMS devices include a movable structure that is held above a substrate with a gap therebetween. For example, in a MEMS device that realizes an acceleration sensor, when acceleration acts on the device, the movable part of the movable structure is relatively displaced with respect to the substrate, and the capacitance between the movable part and the substrate changes. By detecting the change in capacitance between the movable part and the substrate, the acceleration acting on the device can be detected.

  In the MEMS device as described above, there may occur a situation (sticking) in which the movable structure is fixed in contact with the substrate. If sticking occurs, the movable structure is not fixed to the substrate and cannot perform its original function. Therefore, for example, Patent Documents 1-3 disclose a technique for preventing sticking in a MEMS device.

  Patent Documents 1 and 2 disclose a technique for suppressing sticking by roughening the surfaces of the movable structure and the substrate.

  Patent Document 3 discloses a technique for suppressing sticking by forming a thin convex portion on the surfaces of the movable structure and the substrate later.

JP 2007-268704 A Japanese Patent Laid-Open No. 11-340477 JP 2002-160363 A

  When the top surface side of the substrate and the bottom surface side of the movable structure are roughened as in the techniques of Patent Document 1 and Patent Document 2, when the substrate and the movable structure are repeatedly contacted, the fineness formed on the surface There is a possibility that the unevenness will be worn out and sticking cannot be prevented.

  As in the technique of Patent Document 3, when a fine convex portion is formed later on the surface of the movable structure and the substrate, when the substrate and the movable structure are repeatedly contacted, the convex portion formed later is peeled off. As a result, sticking may not be prevented.

  In any of the sticking prevention techniques according to the prior art, it is difficult to prevent sticking over a long period of time because the protrusions for preventing the surface contact between the movable structure and the substrate are worn or peeled off. Even when a MEMS device is used for a long period of time, a technique capable of reliably preventing sticking is expected.

  The present invention solves the above problems. The present invention provides a technology capable of reliably preventing sticking over a long period of time in a MEMS device including a substrate and a movable structure.

  The MEMS device disclosed in this specification is a MEMS device including a substrate and a movable structure. The movable structure includes a movable part disposed above the substrate with a gap, a fixed part fixed to the substrate via an insulating film, and a support beam connecting the movable part and the fixed part. The MEMS device has a first protrusion formed continuously from the movable structure on the lower surface side of the movable structure. The MEMS device has a second convex portion formed continuously from the substrate on the upper surface side of the substrate. In the MEMS device, the first convex portion and the second convex portion have substantially the same size and are arranged to face each other.

  In the above MEMS device, when the movable structure sinks greatly toward the substrate, the lower surface of the first convex portion on the lower surface side of the movable structure and the upper surface of the second convex portion on the upper surface side of the substrate are in contact with each other. Thus, the movable structure is prevented from sinking further toward the substrate. The contact area between the movable structure and the substrate at this time is very small compared to the contact area when the first and second protrusions are not formed. Thereby, the adhesive force resulting from van der Waals force etc. when a movable structure and a board | substrate contact can be reduced. Occurrence of a situation (sticking) in which the movable structure and the substrate are fixed in contact with each other can be suppressed.

  In the above MEMS device, since the first convex portion is continuously formed from the movable structure, the first convex portion is not peeled off from the movable structure, and the strength is high. Moreover, since the 2nd convex part is continuously formed from the board | substrate, a 2nd convex part does not peel from a movable structure, but its intensity | strength is high. Even when the MEMS device is used for a long period of time and the first convex portion and the second convex portion repeatedly collide, the first convex portion and the second convex portion are less likely to cause wear and peeling, Thus, sticking can be reliably prevented.

  In said MEMS device, it is preferable that the 1st convex part is continuously formed from the movable part in the lower surface side of the movable part.

  In the above MEMS device, when the movable part sinks with respect to the substrate, the first convex part and the second convex part formed below the movable part come into contact with each other, so that the surface contact between the movable part and the substrate is achieved. Can be suppressed.

  Or as for said MEMS device, it is preferable that the 1st convex part is continuously formed from the support beam in the lower surface side of the support beam.

  In the MEMS device described above, when the movable part sinks with respect to the substrate, the first convex part and the second convex part formed below the support beam come into contact with each other, thereby making the surface contact between the movable part and the substrate. Can be suppressed. In this MEMS device, since it is not necessary to provide a convex portion for preventing sticking below the movable portion, the degree of freedom in designing the region below the movable portion can be increased.

  Said MEMS device can be suitably manufactured with the following method. The method includes a step of preparing an SOI substrate in which a silicon insulating film is formed between a lower silicon layer and an upper silicon layer, a step of etching the upper silicon layer in accordance with the shape of the movable structure, and the movable structure. A step of partially etching the silicon insulating film below the substrate, a step of forming a silicon insulating film on the surfaces of the upper silicon layer and the lower silicon layer, and a step of etching the silicon insulating film below the movable structure ing.

  In the above manufacturing method, after the silicon insulating film below the movable structure is partially etched, the silicon insulating film partially remains below the movable structure. In the subsequent step of forming the silicon insulating film, this remaining silicon insulating film serves as a mask, and a new silicon insulating film is newly formed only on the exposed portions of the lower and upper silicon layers. It is formed. At this time, in the part where the silicon insulating film is newly formed, the interface between the silicon insulating film and the silicon layer enters inside, but in the part where the silicon insulating film remains from the beginning, the silicon insulating film and the silicon layer The position of the interface with is almost unchanged. Thereafter, by etching the silicon insulating film below the movable structure, the first convex portion and the second convex portion are formed in the upper silicon layer and the lower silicon layer, respectively. The 1st convex part is formed continuously from the movable structure, and the 2nd convex part is formed continuously from the substrate. According to the above manufacturing method, the first convex portion and the second convex portion having substantially the same size are formed by a simple method on the lower surface side of the movable structure and the upper surface side of the substrate so as to face each other. Can do.

  According to the above manufacturing method, when the silicon insulating film below the movable structure is partially etched, the first and second convex portions that are finally formed are adjusted by adjusting the etching time. The size when viewed in plan can be adjusted. It can prevent that a 1st convex part and a 2nd convex part become small too much, and can ensure the intensity | strength of a 1st convex part and a 2nd convex part. A MEMS device that can reliably prevent sticking over a long period of time can be manufactured.

  According to the present invention, sticking can be reliably prevented over a long period of time in a MEMS device including a substrate and a movable structure.

1 is a plan view of a MEMS device 10 of Example 1. FIG. It is the II-II sectional view taken on the line of FIG. 6 is a diagram illustrating a method for manufacturing the MEMS device 10 of Example 1. FIG. 6 is a diagram illustrating a method for manufacturing the MEMS device 10 of Example 1. FIG. 6 is a diagram illustrating a method for manufacturing the MEMS device 10 of Example 1. FIG. 6 is a diagram illustrating a method for manufacturing the MEMS device 10 of Example 1. FIG. It is a figure which shows typically the position of the interface of a silicon oxide and a silicon layer at the time of a silicon layer oxidizing. 6 is a plan view of a MEMS device 20 of Example 2. FIG. It is the IX-IX sectional view taken on the line of FIG.

The features of the preferred embodiment are listed first.
(Feature 1) A MEMS device is manufactured from an SOI substrate in which a silicon oxide film is formed between a lower silicon layer and an upper silicon layer.
(Feature 2) The MEMS device is used as an acceleration sensor.

  Hereinafter, the MEMS device 10 according to the first embodiment will be described with reference to the drawings. FIG. 1 is a plan view of the MEMS device 10, and FIG. 2 is a cross-sectional view taken along line II-II of FIG. The MEMS device 10 is manufactured by using a semiconductor manufacturing process from an SOI (Silicon on Insulator) substrate in which a silicon oxide film is formed between a lower silicon layer and an upper silicon layer.

  As shown in FIGS. 1 and 2, a MEMS device 10 includes a substrate 100 formed on a lower silicon layer and a movable structure formed on an upper silicon layer and held above the substrate 100 with a gap therebetween. A body 102 is provided. As shown in FIG. 1, the movable structure 102 holds the movable portion 104 whose outer shape when viewed in plan is a rectangular shape, the support beam 106 extending from the end of the movable portion 104, and the support beam 106. A holding unit 108 is provided. The support beam 106 is an elongated beam, and connects the movable portion 104 and the holding portion 108. The holding part 108 is formed wider than the support beam 106. As shown in FIG. 2, the holding portion 108 is fixed to the substrate 100 via the insulating layer 110. In the MEMS device 10 of the present embodiment, since the support beam 106 is formed to have low rigidity, the movable portion 104 has a Y axis (an axis extending in the vertical direction in FIG. 1) and a Z axis ( It can be displaced in two axial directions (axis extending in the direction perpendicular to the plane of FIG. 1).

  The MEMS device 10 can be used as an acceleration sensor. When acceleration in the Z direction acts on the MEMS device 10, the movable unit 104 is displaced in the Z direction with respect to the substrate 100. Then, the electrostatic capacitance between the movable part 104 and the substrate 100 changes. By detecting this change in capacitance as an electrical signal, the acceleration in the Z direction can be calculated from the detected change in capacitance.

  Moreover, the MEMS device 10 can also be used as an angular velocity sensor by providing an actuator in the movable portion 104. For example, when the movable portion 104 is vibrated in the Y direction by the actuator, the angular velocity around the X axis (the axis extending in the left-right direction in FIG. 1) of the MEMS device 10 with the movable portion 104 vibrating in the Y direction. Acts, the Coriolis force in the Z direction acts on the movable portion 104, and the movable portion 104 is displaced in the Z direction with respect to the substrate 100. The capacitance between the movable portion 104 and the substrate 100 changes with the displacement in the Z direction, and the change in capacitance is detected as an electrical signal, so that the detected change in capacitance can be calculated as X The angular velocity around the axis can be calculated.

  As shown in FIG. 1, the movable portion 104 has a plurality of through holes 112. The through hole 112 is an etching hole for etching a silicon oxide film that is a sacrificial layer when the MEMS device 10 is manufactured from an SOI substrate. The through holes 112 are arranged in the X direction and the Y direction at equal intervals over the entire movable portion 104, and the movable portion 104 has a lattice shape. In the MEMS device 10 of the present embodiment, the outer shape of the movable portion 104 is formed in a rectangular shape of 500 μm square, and each through hole 112 is formed in a rectangular shape of 5 μm square, and between the adjacent through holes 112. The intervals in the X direction and the Y direction are both 5 μm.

  As shown in FIG. 2, the movable portion 104 has a plurality of first convex portions 114 formed continuously from the movable portion 104 on the lower surface side. In this embodiment, the distance between the substrate 100 and the movable portion 104 is 2 μm, the height of the first convex portion 114 is about 0.6 μm, and the size of the first convex portion 114 when viewed in plan is 1 μm to 2 μm. As shown in FIG. 1, the 1st convex part 114 is arrange | positioned in the position corresponded to the lattice point of the movable part 104 formed in the grid | lattice form.

  As shown in FIG. 2, the substrate 100 has a plurality of second convex portions 116 formed continuously from the substrate 100 on the upper surface side. In the present embodiment, the height of the second convex portion 116 is about 0.6 μm, and the size of the second convex portion 116 in a plan view is 1 μm to 2 μm. Each 2nd convex part 116 is arrange | positioned in the position facing the corresponding 1st convex part 114 mutually.

  In the MEMS device 10 of the present embodiment, when the movable portion 104 sinks greatly toward the substrate 100, the lower surface of the first convex portion 114 on the lower surface side of the movable portion 104 and the second convex surface on the upper surface side of the substrate 100. The upper surface of the part 116 contacts and prevents the movable part 104 from sinking further toward the substrate 100. At this time, the contact area between the movable portion 104 and the substrate 100 is very small compared to the contact area between the movable portion 104 and the substrate 100 when the first convex portion 114 and the second convex portion 116 are not formed. Thereby, the adhesive force resulting from van der Waals force etc. when the movable part 104 and the board | substrate 100 contact can be reduced. According to the MEMS device 10 of the present embodiment, it is possible to suppress the occurrence of a situation (sticking) in which the movable portion 104 is fixed to the substrate 100.

  In the MEMS device 10 of the present embodiment, since the first convex portion 114 is continuously formed from the movable portion 104, the first convex portion 114 is not peeled off from the movable portion 104, and the strength is high. Moreover, since the 2nd convex part 116 is continuously formed from the board | substrate 100, the 2nd convex part 116 does not peel from the movable part 104, but its intensity | strength is high. Even if the MEMS device 10 is used for a long period of time and the first convex portion 114 and the second convex portion 116 repeatedly collide, the first convex portion 114 and the second convex portion 116 may be worn or peeled off. And the MEMS device 10 capable of reliably preventing sticking over a long period of time can be realized.

  Hereinafter, a method for manufacturing the MEMS device 10 according to the present embodiment will be described with reference to FIGS. 3 to 6 correspond to the II-II cross section of FIG. 1, that is, the cross section of FIG.

  First, as shown in FIG. 3, an SOI substrate 300 in which a silicon oxide film 304 is formed between a lower silicon layer 302 and an upper silicon layer 306 is prepared, and a resist pattern 308 is formed on the upper surface of the upper silicon layer 306 by photolithography. Form. The resist pattern 308 corresponds to the shape of the movable portion 104, the support beam 106, and the holding portion 108 of the movable structure 102 in FIG.

  Next, as shown in FIG. 4, the upper silicon layer 306 is etched by a DRIE (Deep Reactive Ion Etching) method. As a result, the upper silicon layer 306 is trimmed into a shape corresponding to the resist pattern 308, and portions corresponding to the movable portion 104, the support beam 106, and the holding portion 108 in FIG. 1 are formed.

  Next, as shown in FIG. 5, after removing the resist pattern 308 on the upper surface of the upper silicon layer 306, the silicon oxide film 304 is etched by isotropic etching using buffered hydrofluoric acid. Hereinafter, this process is also referred to as a first sacrificial layer etching. At this time, a plurality of through holes 112 which are etching holes are formed in a portion corresponding to the movable portion 104 of the upper silicon layer 306 (see FIG. 1), so that the etching solution flows through each etching hole. The silicon oxide film 304 existing below the movable portion 104 is also etched quickly. The etching time here is set to be short, and the silicon oxide film 304 that is not removed remains in the portion where the etching solution is most difficult to go around, that is, the portion corresponding to the lattice point of the movable portion 104 formed in a lattice shape. .

  Next, as shown in FIG. 6, a silicon oxide film 310 is formed on the surfaces of the lower silicon layer 302 and the upper silicon layer 306 by thermal oxidation. By this thermal oxidation treatment, a new silicon oxide film 310 is formed on the surface where the silicon is exposed in the lower silicon layer 302 and the upper silicon layer 306. As shown in FIG. 7, when the silicon oxide film 310 is formed on the surface of the upper silicon layer 306 by thermal oxidation, the interface between the silicon oxide film 310 and the upper silicon layer 306 is 45% more than the surface of the original upper silicon layer 306. Get inside about%. However, as shown in FIG. 6, the portion already covered with the silicon oxide film 304 before the thermal oxidation process is performed (that is, the lower surface of the upper silicon layer 306 is covered with the remaining silicon oxide film 304). The interface between the upper silicon layer 306 and the silicon oxide film 304 hardly moves inward. On the lower surface of the upper silicon layer 306, the interface with the silicon oxide film 310 enters more inside than the interface with the silicon oxide film 304. Similarly, also on the upper surface of the lower silicon layer 302, the interface with the silicon oxide film 310 enters more inside than the interface with the silicon oxide film 304.

  Then, the silicon oxide film 304 remaining below the movable portion 104 and the newly formed silicon oxide film 310 are removed by isotropic etching using buffered hydrofluoric acid. Hereinafter, this process is also referred to as a second sacrificial layer etching. Thereby, the MEMS device 10 as shown in FIG. 2 can be manufactured. According to the above manufacturing method, the first convex portion 114 and the second convex portion 116 having substantially the same size can be formed on the lower surface side of the movable portion 104 and the upper surface side of the substrate 100 so as to face each other. it can.

  The first convex portion 114 is formed by cutting out the lower surface side of the movable portion 104 by partial thermal oxidation and etching, and is formed continuously from the movable portion 104. The second convex portion 116 is formed by cutting out the upper surface side of the substrate 100 by partial thermal oxidation and etching, and is continuously formed from the substrate 100. According to the above manufacturing method, the first convex portion 114 continuously formed from the movable portion 104 and continuously from the substrate 100 in a positional relationship facing each other on the lower surface side of the movable portion 104 and the upper surface side of the substrate 100. Thus, the second protrusion 116 can be formed by a simple method.

  According to said manufacturing method, the magnitude | size when planarly viewing the 1st convex part 114 and the 2nd convex part 116 is adjusted to a desired magnitude | size by adjusting the etching time in the 1st sacrificial layer etching. be able to. Therefore, by adjusting the size of the first convex portion 114 and the second convex portion 116 in plan view so as not to be too small (for example, securing a size of about 1 μm to 2 μm), the first The strength of the convex portion 114 and the second convex portion 116 can be ensured.

  In the above description, the case where the first protrusions 114 and the second protrusions 116 are formed in lattice points by arranging the through holes 112 at equal intervals in the X direction and the Y direction has been described. By making the intervals unequal, the shape and arrangement of the first convex portion 114 and the second convex portion 116 can be changed. For example, if the interval between part of the through-holes 112 is 15 μm and the interval between other parts is 5 μm, only the silicon oxide film 304 at the interval of 15 μm is left in the first sacrificial layer etching, leaving 5 μm. It is possible to remove the silicon oxide film 304 at the locations defined by the intervals. As a result, the first convex portion 114 and the second convex portion 116 can be formed only at a location where the interval between the through holes 112 is 15 μm.

  Hereinafter, the MEMS device 20 according to the second embodiment will be described with reference to the drawings. 8 is a plan view of the MEMS device 20, and FIG. 9 is a cross-sectional view taken along the line IX-IX of FIG.

  As shown in FIGS. 8 and 9, the MEMS device 20 includes a substrate 800 formed on the lower silicon layer and a movable structure formed on the upper silicon layer and held above the substrate 800 with a gap therebetween. A body 802 is provided. As shown in FIG. 8, the movable structure 802 holds a movable portion 804 having a rectangular outer shape when viewed in plan, a support beam 806 extending from the end of the movable portion 804, and the support beam 806. A holding unit 808 is provided. The support beam 806 is an elongated beam, and connects the movable portion 804 and the holding portion 808. The holding portion 808 is formed wider than the support beam 806. As shown in FIG. 9, the holding portion 808 is fixed to the substrate 800 with an insulating layer 810 interposed therebetween. Since the support beam 806 is formed to have low rigidity, the movable portion 804 can move in two directions of the Y axis and the Z axis with respect to the substrate 800. Similar to the MEMS device 10 of the first embodiment, the MEMS device 20 of the present embodiment can be used as an acceleration sensor or an angular velocity sensor.

  As shown in FIG. 8, the movable portion 804 is formed with a plurality of through holes 812 which are etching holes when the sacrificial layer is etched. The through holes 812 are arranged in the X direction and the Y direction at equal intervals over the entire movable portion 804, and the movable portion 804 has a lattice shape. Compared to the MEMS device 10 of the first embodiment, in the MEMS device 20 of the present embodiment, a larger number of through holes 812 are arranged more densely, and the interval between the adjacent through holes 812 is narrower. ing.

  As shown in FIG. 9, the support beam 806 has a first convex portion 814 formed continuously from the support beam 806 on the lower surface side thereof. Further, the substrate 800 has a plurality of second convex portions 816 formed continuously from the substrate 800 on the upper surface side. The second convex portion 816 is disposed at a position facing the corresponding first convex portion 814. Unlike the MEMS device 10 of the first embodiment, in the MEMS device 20 of the present embodiment, no convex portion is formed on the lower surface side of the movable portion 804, and the portion facing the movable portion 804 on the upper surface side of the substrate 800. Has no protrusions.

  In the MEMS device 20 of the present embodiment, when the movable portion 804 sinks greatly toward the substrate 800, the lower surface of the first convex portion 814 on the lower surface side of the support beam 806 and the second convex surface on the upper surface side of the substrate 800. The upper surface of the portion 816 comes into contact with the movable portion 804 to prevent the movable portion 804 from sinking further toward the substrate 800. At this time, the contact area between the support beam 806 and the substrate 800 is very small compared to the contact area between the movable portion 804 and the substrate 800 when the first protrusion 814 and the second protrusion 816 are not formed. According to the MEMS device 20 of the present embodiment, it is possible to suppress the occurrence of a situation (sticking) in which the movable portion 804 is fixed to the substrate 800.

  The MEMS device 20 according to the present embodiment is manufactured by substantially the same method as the MEMS device 10 according to the first embodiment. In the MEMS device 20 of the present embodiment, since the large number of through holes 812 are densely arranged in the movable portion 804, the silicon oxide film existing below the movable portion 804 is completely formed during the first sacrificial layer etching. As a result, the silicon oxide film existing below the support beam 806 partially remains. Then, the MEMS device 20 shown in FIGS. 8 and 9 can be manufactured by performing a thermal oxidation process and a second sacrificial layer etching.

  As mentioned above, although the Example of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  For example, in the above-described embodiment, the case of performing isotropic etching using buffered hydrofluoric acid in the first sacrificial layer etching and the second sacrificial layer etching has been described, but instead of etching using buffered hydrofluoric acid. Thus, vapor etching using vapor-phase hydrofluoric acid may be performed.

  In the above embodiment, the case where the MEMS device is manufactured by the semiconductor manufacturing process from the SOI substrate in which the silicon oxide film is formed between the lower silicon layer and the upper silicon layer has been described. Unlike this, first, the upper silicon layer and the lower silicon layer are manufactured separately, and the first and second protrusions are formed on the respective surfaces, and then both are formed on the silicon oxide film. The MEMS device may be manufactured by adhering with a sandwich.

  In the above embodiment, the MEMS device used as a sensor for detecting a physical quantity such as acceleration or angular velocity has been described as an example, but the scope to which the present invention can be applied is not limited thereto. For example, a MEMS device having a configuration in which a mirror is provided on the upper surface of the movable portion and supported by a support beam so that the movable portion can swing around the swing axis can be used for an optical deflection apparatus. Also for such a MEMS device, according to the present invention, it is possible to suppress sticking in which the movable portion is fixed to the substrate. The present invention can be applied to any MEMS device provided with a movable structure that is held above a substrate with a gap.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

10, 20 MEMS device 100 Substrate 102 Movable structure 104 Movable portion 106 Support beam 108 Holding portion 110 Insulating layer 112 Through hole 114 First convex portion 116 Second convex portion 300 SOI substrate 302 Lower silicon layer 304 Silicon oxide film 306 Upper side Silicon layer 308 Resist pattern 310 Silicon oxide film 800 Substrate 802 Movable structure 804 Movable portion 806 Support beam 808 Holding portion 810 Insulating layer 812 Through hole 814 First convex portion 816 Second convex portion

Claims (4)

A MEMS device comprising a substrate and a movable structure,
The movable structure includes a movable part disposed above the substrate with a gap, a fixed part fixed to the substrate via an insulating film, and a support beam connecting the movable part and the fixed part.
On the lower surface side of the movable structure, it has a first protrusion formed continuously from the movable structure,
On the upper surface side of the substrate, there is a second protrusion formed continuously from the substrate,
A MEMS device in which a first convex portion and a second convex portion have substantially the same size and are arranged to face each other.   The MEMS device according to claim 1, wherein the first convex portion is continuously formed from the movable portion on the lower surface side of the movable portion.   The MEMS device according to claim 1, wherein the first convex portion is formed continuously from the support beam on the lower surface side of the support beam. A method of manufacturing the MEMS device of claim 1, comprising:
Preparing an SOI substrate having a silicon insulating film formed between a lower silicon layer and an upper silicon layer;
Etching the upper silicon layer according to the shape of the movable structure;
Partially etching the silicon insulating film below the movable structure;
Forming a silicon insulating film on the surfaces of the upper silicon layer and the lower silicon layer;
A method comprising a step of etching a silicon insulating film below a movable structure.

Images