JP2012178710A - Mems device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture an MEMS device that has structure, in which an electrode surface of a substrate side and an undersurface of a vibrating member oppose to each other with a sufficient narrow gap therebetween, and uses torsional vibration.SOLUTION: A manufacturing method of an MEMS device comprising base materials, a floating structure and a raised opposing section that is detached and opposes with respect to a partial region of the floating structure includes: a step S1 for preparing an SOI substrate; a step S2 for forming the raised opposing section, a supporting beam section or the like by patterning a first silicon layer; a step S3 for removing a first region halfway in a thickness direction by etching; a step S4 for disconnecting between the raised opposing section and a second silicon layer by etching at least a part of an intermediate insulation layer; a step S5 for bonding the base materials to each other; and a step S6 for separating the raised opposing section from an outer frame section while forming the floating structure by patterning the second silicon layer.

Description

  The present invention relates to a MEMS device and a manufacturing method thereof.

  In recent years, micro electro mechanical systems (MEMS) technology has been developed that uses microfabrication technology in the semiconductor field to form a fine mechanical structure integrated with an electronic circuit, and its application to filters and resonators has been studied. ing.

  Among these, the micromechanical resonator created by such MEMS technology is preferably used for RF radio such as a remote keyless entry system and spread spectrum communication. An example of a MEMS filter using a micromechanical resonator created by such a MEMS technology is disclosed in Japanese Patent Laid-Open No. 2006-41911 (Patent Document 1). The MEMS filter device described in this document includes a resonator. The resonator included in this resonator has a square plate shape, is arranged parallel to the substrate surface and spaced from the substrate, and is supported by a cylinder connected to the substrate surface. By applying an AC voltage to a fixed electrode formed to face each side of the resonator with a predetermined interval, an electrostatic force is generated between the vibrator and the fixed electrode, and the resonator It is a mechanism that vibrates. In this case, the center and corner of each side of the vibrator vibrate horizontally. When the resonators are connected by a connecting body, the connecting body transmits longitudinal vibration.

RF-MEMS filter using silicon process with high affinity to semiconductor process is published by Akinori Hashimura et al., "Development of RF-MEMS filter using torsional vibration", IEICE Technical Report, The Institute of Electronics, Information and Communication Engineers. , IEICE Technical Report MW2005-185 (2006-3) (non-patent document 1). In this document, it is introduced that a resonator using a torsional vibration mode is effective in achieving both miniaturization and high Q factor.

  An apparatus made using the MEMS technology, such as the resonator exemplified here, is called a “MEMS device”. In order to manufacture a MEMS device, a structure body formed by patterning a silicon layer and a base material having an insulating surface may be overlapped and bonded.

JP 2006-41911 A

Akinori Hashimura et al., “Development of RF-MEMS filters using torsional vibration”, IEICE Technical Report, IEICE Technical Report, IEICE Technical Report MW2005-185 (2006-3)

  As a MEMS device using the torsional vibration mode, a device in which a beam-like vibration member is installed on a substrate can be considered. In that case, an electrode for applying vibration to the beam-like vibrating member is provided on the surface of the substrate, or is provided on the upper surface of a member provided on the surface of the substrate at a certain height. The lower surface of the vibration member is disposed so as to face the electrode with a distance.

In order to produce such a structure, first, the vibration member portion is uniquely formed of Si. On the other hand, a desired electrode pattern and lead-out wiring are formed on the surface of a separately prepared glass substrate by a conductor film. Thus, the separately produced vibrating member and glass substrate are anodically bonded to each other. At this time, it is desired that the lower surface of the vibration member is opposed to the surface of the substrate through a gap as narrow as possible, but conventionally, it has been difficult to make the gap less than 1 μm.

  Further, even if the structure in which the leg portion and the vibration member are combined as a single body and the height difference between the lower surface of the leg portion and the lower surface of the vibration member can be precisely less than 1 μm, the anodic bonding process Then, since a voltage of several hundred volts is applied under the condition of several hundred degrees Celsius, there is a problem that sticking occurs between the vibrating member and the electrode on the substrate surface.

  Therefore, the present invention provides a MEMS device using torsional vibration, which has a structure in which the electrode surface on the substrate side and the lower surface of the vibration member face each other with a sufficiently narrow gap, and can be easily manufactured, and It aims at providing the manufacturing method.

  In order to achieve the above object, a method of manufacturing a MEMS device according to the present invention includes a base material having a flat main surface and a base member that is relatively fixed to the base material so as to be separated from the main surface. A floating structure extending in parallel to the main surface, and a raised portion that is fixed to the main surface and is opposed to the partial area of the floating structure from a side close to the main surface while being separated from the floating structure It is a method of manufacturing a MEMS device provided with an opposing part. This manufacturing method includes a step of preparing an SOI substrate laminated so as to sandwich an intermediate insulating layer between a first silicon layer and a second silicon layer, and patterning the first silicon layer, whereby the outer frame portion, A step of forming a raised facing portion, a supporting beam portion connecting the raised facing portion and the outer frame portion, and a first region that is at least part of the supporting beam portion from the second silicon layer. Etching and removing from the surface on the far side to the middle in the thickness direction, and removing the bulk by etching away at least a portion of the intermediate insulating layer located between the raised facing portion and the second silicon layer. The step of disconnecting the connection between the facing portion and the second silicon layer, and the second silicon layer is opposite to the outer frame portion and the raised facing portion of the first silicon layer. Forming the floating structure by patterning the second silicon layer, and further covering the floating structure in the support beam portion. Removing the uncovered region to separate the raised facing portion from the outer frame portion.

  According to the present invention, it is possible to easily provide a MEMS device having a structure in which the electrode surface on the substrate side and the lower surface of the vibration member are opposed to each other with a sufficiently narrow gap and utilizing torsional vibration.

It is a flowchart of the manufacturing method of the MEMS device in Embodiment 1 based on this invention. It is a top view which shows the state by which the 1st silicon layer was patterned by process S2 of the manufacturing method of the MEMS device in Embodiment 1 based on this invention. It is a perspective view in the state where the 1st silicon layer was patterned by process S2 of the manufacturing method of the MEMS device in Embodiment 1 based on the present invention. It is explanatory drawing which shows the 1st area | region scheduled to be removed by the etching to halfway in the thickness direction by process S3 of the manufacturing method of the MEMS device in Embodiment 1 based on this invention. It is a perspective view of the state where the 1st field was etched to the middle of the thickness direction in process S3 of the manufacturing method of the MEMS device in Embodiment 1 based on the present invention. It is arrow sectional drawing regarding the VI-VI line in FIG. It is a perspective view of the state after etching an intermediate insulating layer isotropically in process S4 of the manufacturing method of the MEMS device in Embodiment 1 based on this invention. It is arrow sectional drawing regarding the VIII-VIII line in FIG. It is sectional drawing of the state which affixed the base material by process S5 of the manufacturing method of the MEMS device in Embodiment 1 based on this invention. It is sectional drawing of the state which polished and thinned the 2nd silicon layer in the middle of the manufacturing method of the MEMS device in Embodiment 1 based on this invention. It is sectional drawing of the state which formed the mask pattern in the upper surface of the 2nd silicon layer in the middle of the manufacturing method of the MEMS device in Embodiment 1 based on this invention. It is a top view in the state where patterning of the 2nd silicon layer was completed in the middle of etching of process S6 of a manufacturing method of a MEMS device in Embodiment 1 based on the present invention, and the patterning of the 1st silicon layer has not been performed yet. . It is sectional drawing of the state which the etching of process S6 of the manufacturing method of the MEMS device in Embodiment 1 based on this invention was complete | finished. It is a perspective view in the state where the mask pattern was removed in the middle of the manufacturing method of the MEMS device in Embodiment 1 based on this invention. It is a top view of the MEMS device obtained with the manufacturing method of the MEMS device in Embodiment 1 based on this invention. It is arrow sectional drawing regarding the XVI-XVI line | wire in FIG. It is explanatory drawing which shows the 1st area | region scheduled to be removed by the etching to halfway in the thickness direction by process S3 of the manufacturing method of the MEMS device in Embodiment 2 based on this invention. It is sectional drawing of the state after performing the etching of an intermediate | middle insulating layer by process S4 of the manufacturing method of the MEMS device in Embodiment 2 based on this invention. It is sectional drawing of the state before starting the etching of process S6 of the manufacturing method of the MEMS device in Embodiment 2 based on this invention. It is sectional drawing of the state which finished the etching of process S6 of the manufacturing method of the MEMS device in Embodiment 2 based on this invention. It is sectional drawing of the state which removed the mask pattern in the middle of the manufacturing method of the MEMS device in Embodiment 2 based on this invention, and is also sectional drawing of the MEMS device in Embodiment 4. FIG. It is a top view of the state which removed the mask pattern in the middle of the manufacturing method of the MEMS device in Embodiment 2 based on this invention, and is also a top view of the MEMS device in Embodiment 4. It is the elements on larger scale of the pattern formed in a 1st silicon layer at process S2 of the manufacturing method of the MEMS device in Embodiment 3 based on this invention. It is a perspective view of the vicinity of the raising facing part in the state where step S4 of the method for manufacturing the MEMS device in the third embodiment based on the present invention is finished. It is sectional drawing of the state which finished step S6 of the manufacturing method of the MEMS device in Embodiment 3 based on this invention, and is also sectional drawing of the MEMS device in Embodiment 5. FIG. It is an enlarged view of the center part of FIG. It is a top view of the MEMS device obtained with the manufacturing method of the MEMS device in Embodiment 3 based on this invention, and is also a top view of the MEMS device in Embodiment 5. It is a perspective view of the MEMS device based on a reference technique. It is a top view of the MEMS device based on a reference technique. It is arrow sectional drawing regarding the XXX-XXX line in FIG. It is sectional drawing of the SOI substrate used with the manufacturing method of the MEMS device based on a reference technique. It is a top view of the state after patterning the 1st silicon layer of an SOI substrate with the manufacturing method of the MEMS device based on a reference technique. It is arrow sectional drawing regarding the XXXIII-XXXIII line | wire in FIG. It is sectional drawing of the state after etching an intermediate insulating layer isotropically with the manufacturing method of the MEMS device based on a reference technique. It is a top view of the base material used with the manufacturing method of the MEMS device based on a reference technique. It is sectional drawing of the state which affixed the base material with the manufacturing method of the MEMS device based on a reference technique. It is sectional drawing of the state after patterning a 2nd silicon layer with the manufacturing method of the MEMS device based on a reference technique.

  In making the present invention, the inventors firstly, as a structure of the MEMS device, a base material having a flat main surface and a base member that is relatively fixed to the base material so as to be separated from the main surface, and laterally. A floating structure that extends and is fixed to the main surface, is spaced apart from the floating structure, and is opposed to a part of the floating structure that is opposed to the main surface from the side close to the main surface. The structure provided with the part was assumed. This is hereinafter referred to as “reference technology”. This reference technique is conceivable for the purpose of achieving the object of the present invention described above. A structure that satisfies such a condition may be, for example, when the MEMS device is a resonator, but a structure that satisfies the same requirements may be required for a MEMS device other than the resonator.

  Taking a case where the MEMS device is a resonator as an example, a specific example of a structure based on a reference technique will be described. This structure is shown in FIG. 28, FIG. 29, and FIG. 29 is a plan view of the structure shown in FIG. 28, and FIG. 30 is a cross-sectional view taken along the line XXX-XXX in FIG. The resonator 901 as a MEMS device is a base member 20 having a flat main surface 20a and a vibration part that is fixed to the base member 20 so as to be separated from the main surface 20a and extends laterally. The floating structure 2 is fixed to the main surface 20a, and is spaced apart from the floating structure 2 and is opposed to the part 2v of the floating structure 2 from the side close to the main surface 20a. Part 5. Resonator 901 includes electrode pattern 4 on main surface 20a. The electrode pattern 4 includes lead wires 7 and external connection terminals 8. The resonator 901 includes a basic silicon layer 21, an intermediate insulating layer 22, and an elevated silicon layer 23. The resonator 901 includes an outer wall portion 9 that surrounds the floating structure 2. The outer wall portion 9 has a notch portion 10. The raising facing portion 5 faces the region 2v of the floating structure 2 through the gap 6. The raising facing portion 5 is a block for causing vertical vibration in the region 2v. The electrode pattern 4 is for applying a voltage between the raised facing portion 5 and the floating structure 2. When a voltage is applied between the raised facing portion 5 and the floating structure 2, a vertical vibration is generated in the region 2 v, and this vibration is transmitted to the entire floating structure 2. Torsional vibrations occur in some areas.

  Assuming the case where the above-described resonator is manufactured as a MEMS device, a manufacturing method thereof will be described. First, an SOI substrate 100 as shown in FIG. 31 is prepared. The SOI substrate 100 includes a first silicon layer 101, an intermediate insulating layer 102, and a second silicon layer 103. The first silicon layer 101 of the SOI substrate 100 is patterned to obtain the structure shown in FIGS. 33 is a cross-sectional view taken along the line XXXIII-XXXIII in FIG. The basic pattern 510 formed from the first silicon layer 101 has the beam-like portion 14 so as to cross the central opening. Further, the structure shown in FIG. 34 is obtained by isotropically etching away the intermediate insulating layer 102 in this structure. That is, the beam-like portion 14 and the second silicon layer 103 are separated by removing the intermediate insulating layer 102 below the beam-like portion 14.

  As shown in FIG. 35, a base material 20 having an electrode pattern 4 formed on the main surface 20a is prepared. The structure shown in FIG. 34 is attached to the main surface 20a of the substrate 20 shown in FIG. FIG. 36 shows the state after pasting. The second silicon layer 103 is polished from the state shown in FIG. 36 to a desired thickness. Further, the second silicon layer 103 is patterned. Thus, the structure shown in FIG. 37 is obtained. The first silicon layer 101 is the basic silicon layer 21, the intermediate insulating layer 102 is the intermediate insulating layer 22, and the second silicon layer 103 is the elevated silicon layer 23. When patterning the second silicon layer 103, the floating structure 2 is formed as a vibrating portion from the second silicon layer 103. At the same time, unnecessary portions of the beam-like portion 14 are also removed, and the beam-like portion 14 A part is raised and remains as a facing portion 5. Further, several steps are performed to obtain the structure shown in FIGS.

  In the above-described MEMS device manufacturing method, a mask for forming the floating structure 2 as the vibrating portion from the second silicon layer 103 is used as it is, and the beam shape located closer to the substrate 20 than the floating structure 2 is used. The exposed portion of the portion 14 is continuously etched. Accordingly, it is assumed that the exposed portion of the beam-like portion 14 is removed over the entire thickness direction. This is because the beam-like portion 14 needs to be completely divided in order to electrically separate the raised facing portion 5 formed by a part of the beam-like portion 14 from other portions. However, if it is attempted to etch until the beam-like portion 14 is completely divided at the exposed portion of the beam-like portion 14, the etching takes a long time. If etching is performed for a long time, the floating structure 2 that should originally be left in a predetermined pattern is over-etched, and the shape accuracy of the floating structure 2 may be deteriorated.

  Therefore, the present invention aims to further solve the problems found by the inventors themselves in the reference technique assumed by the inventors. That is, it is a further object of the present invention to provide a MEMS device and a manufacturing method thereof for preventing the floating structure from being over-etched by etching for separating the raised facing portion in the MEMS device.

(Embodiment 1)
(Production method)
With reference to FIGS. 1-16, the manufacturing method of the MEMS device in Embodiment 1 based on this invention is demonstrated. A flowchart of a method for manufacturing a MEMS device in the present embodiment is shown in FIG. The MEMS device manufacturing method according to the present embodiment includes a base material having a flat main surface, and is relatively fixed to the base material so as to be separated from the main surface, and extends parallel to the main surface. A floating structure, and a raised facing portion that is fixed to the main surface and is spaced apart from the floating structure while facing a part of the floating structure from a side near the main surface. A method of manufacturing a MEMS device, comprising: preparing an SOI substrate laminated so as to sandwich an intermediate insulating layer between a first silicon layer and a second silicon layer; and patterning the first silicon layer A step S2 of forming an outer frame portion, the raised facing portion, and a supporting beam portion connecting the raised facing portion and the outer frame portion, and a first region that is at least a part of the supporting beam portion Before Etching and removing step S3 of etching from the surface far from the second silicon layer to the middle of the thickness direction, and at least a portion of the intermediate insulating layer located between the raised facing portion and the second silicon layer And disconnecting the connection between the raised facing portion and the second silicon layer, and the second silicon layer with respect to the outer frame portion and the raised facing portion of the first silicon layer. Step S5 for attaching the base material so as to cover the entire surface from the opposite side, patterning the second silicon layer to form the floating structure, and further, the floating of the support beam portion And step S6 of separating the raised facing portion from the outer frame portion by removing a region not covered with the structure.

Each step will be described in detail below.
As step S1, an SOI substrate as shown in FIG. 31 is prepared. The SOI substrate 100 is formed by laminating an intermediate insulating layer 102 between a first silicon layer 101 and a second silicon layer 103.

  As step S2, patterning is performed as shown in FIG. That is, by patterning the first silicon layer 101, the outer frame portion 16, the raised facing portion 5 and the support beam portion 15 are formed. A cutout portion 10 is provided at one location on the outer periphery of the outer frame portion 16. The support beam portion 15 connects the raised facing portion 5 and the outer frame portion 16. In the example shown in FIG. 2, the raised facing portion 5 and the support beam portion 15 are formed so as to be aligned in a straight line with the same width, but this is merely an example. In applying the present invention, the raised facing portion 5 and the support beam portion 15 do not have to have the same width. In applying the present invention, the positional relationship in which the raised facing portion 5 and the support beam portion 15 are aligned in a straight line is not necessary. For example, a structure may be employed in which the support beam portions 15 are radially connected to the raised facing portion 5 disposed in the center.

  A perspective view of the structure shown in FIG. 2 is shown in FIG. Only the first silicon layer 101 is patterned, and the intermediate insulating layer 102 and the second silicon layer 103 remain on the entire surface.

  As step S3, as shown in FIG. 4, the first region 17 which is at least a part of the support beam portion 15 is removed by etching from the surface far from the second silicon layer 103 to the middle in the thickness direction. In FIG. 4, the first region 17 is hatched for easy understanding of the portion corresponding to the first region 17 in the support beam portion 15. As a result of etching the first region halfway in the thickness direction, a structure as shown in FIG. 5 is obtained. Further, FIG. 6 shows a cross-sectional view taken along the line VI-VI in FIG. In the portion corresponding to the first region 17 in the support beam portion 15, the first silicon layer 101 is etched and thinned partway in the thickness direction. At this point, the intermediate insulating layer 102 and the second silicon layer 103 remain on the entire surface.

  In step S4, at least a portion of the intermediate insulating layer 102 located between the raised facing portion 5 and the second silicon layer 103 is removed by etching to remove the space between the raised facing portion 5 and the second silicon layer 103. Disconnect the. This etching is isotropic. As a result of etching the intermediate insulating layer 102, a state as shown in FIG. 7 is obtained. In the region where the intermediate insulating layer 102 is exposed, the intermediate insulating layer 102 is completely removed, so that the intermediate insulating layer 102 is not visible in FIG. In FIG. 7, the intermediate insulating layer 102 remains in a partial region below the outer frame portion 16, but the intermediate insulating layer 102 is hidden behind the outer frame portion 16 and is not visible. FIG. 8 shows a cross-sectional view taken along the line VIII-VIII in FIG. In step S4, the portion where the intermediate insulating layer 102 is to be removed by etching is at least a portion located between the raised facing portion 5 and the second silicon layer 103. As a result of this etching, the portion shown in FIGS. As described above, the intermediate insulating layer 102 in other portions may also be removed. For example, the intermediate insulating layer 102 may be completely removed in the projection region of the support beam portion 15 with respect to the second silicon layer 103. However, a part of the intermediate insulating layer 102 should remain under the outer frame portion 16.

  In step S5, the base material 20 is attached so that the outer frame portion 16 and the raised facing portion 5 of the first silicon layer 101 are collectively covered from the side opposite to the second silicon layer 103. . The substrate 20 may be as shown in FIG. The substrate 20 has a main surface 20a. The base material 20 includes the electrode pattern 4 on the main surface 20a. The electrode pattern 4 includes lead wires 7 and external connection terminals 8. As a result of pasting the base material 20 in step S5, the structure shown in FIG. 9 is obtained. In FIG. 9, the substrate 20 is displayed on the lower side and the second silicon layer 103 is displayed on the upper side. In FIG. 9, the cross section of the raising facing portion 5 is visible. The support beam portion 15 extends in a direction perpendicular to the paper surface so as to be connected to the raised facing portion 5. A tunnel 31 is formed in advance in at least one location of the outer frame portion 16 of the first silicon layer 101. As a result of step S5, the lead-out wiring 7 is pulled out through the tunnel 31. As a result of step S <b> 5, the raising facing portion 5 faces the surface of the second silicon layer 103 with the gap 6 interposed therebetween.

  As shown in FIG. 10, the 2nd silicon layer 103 is grind | polished from the opposite side to the base material 20, and the 2nd silicon layer 103 is made thin so that it may become predetermined thickness.

  In step S6, the floating structure 2 is formed by patterning the second silicon layer 103 from the state shown in FIG. 10, and the region of the support beam 15 that is not covered by the floating structure 2 is removed. As a result, the raised facing portion 5 is separated from the outer frame portion 16. For this purpose, first, a mask pattern is formed with a resist on the upper surface of the second silicon layer 103 in the state shown in FIG. This mask pattern corresponds to the planar shape of the floating structure. That is, a mask pattern 18 is formed as shown in FIG. FIG. 11 is a cross-sectional view taken in a direction different from that of FIG. 10 by 90 °. The first region 17 corresponds to a region where the second silicon layer 103 is not covered with the mask pattern 18. The silicon layer is etched using mask pattern 18 as a mask. In this etching, both the second silicon layer 103 and the first silicon layer 101 are patterned by the mask pattern 18. FIG. 12 shows a plan view of the state in which the patterning of the second silicon layer 103 is completed and the patterning of the first silicon layer 101 is not yet performed in the middle of the etching in the step S6. In FIG. 12, the mask pattern 18 is not shown. In FIG. 12, the support beam portion 15 behind the floating structure 2 is partially visible. The visible portion of the support beam portion 15 is the first region 17. As the etching further proceeds, the portion of the support beam 15 that is not covered by the floating structure 2 in FIG. 12 is removed by etching. That is, the portion of the support beam portion 15 that was in the first region 17 is removed.

  When the etching in step S6 is completed, as shown in FIG. 13, the second silicon layer 103 is patterned so that the portions 2a, 2b, and 2c remain, and these become the floating structure 2. Members 19b and 19c remain below the portions 2a and 2c. The members 19b and 19c are unnecessary members, but there is no problem if they remain. By this patterning, the first silicon layer 101 becomes the “base silicon layer 21”, and the second silicon layer 103 becomes the “elevated silicon layer 23”. The intermediate insulating layer 102 partially remaining between the base silicon layer 21 and the elevated silicon layer 23 is renamed as “intermediate insulating layer 22” for convenience of explanation.

  The mask pattern 18 is removed from the state shown in FIG. A perspective view with the mask pattern 18 removed is shown in FIG. At this point, a resonator 901 as a MEMS device has been completed. A plan view of the resonator 901 is as shown in FIG. The floating structure 2 is surrounded by the outer wall 9. The raised facing portion 5 and the members 19b and 19c are hidden under the floating structure 2. As a result of the etching in step S <b> 6, the raised facing portion 5 has already been separated from the outer frame portion 16. Of the two silicon layers included in the outer wall portion 9, one layer closer to the main surface 20 a is the outer frame portion 16. Both the raised facing portion 5 and the outer frame portion 16 are originally formed from the first silicon layer 101. As a result of the etching in step S6, the members 19b and 19c are also separated from the outer frame portion 16 and have independent shapes. A lead-out wiring 7 is connected to the raising facing portion 5. No wiring is connected to the members 19b and 19c. FIG. 16 is a cross-sectional view taken along the line XVI-XVI in FIG.

(Action / Effect)
According to the present embodiment, it is possible to easily provide a MEMS device using a torsional vibration having a structure in which the electrode surface on the substrate side and the lower surface of the vibration member face each other with a sufficiently narrow gap.

  Further, according to the present embodiment, the first region 17 that is a part of the support beam portion 15 is started at the time of starting the etching in the step S6, that is, the etching for separating the raised facing portion in the MEMS device. Is already thinned, the first region 17 is divided only by a short etching time. By dividing the first region 17, the purpose of separating the raised facing portion 5 from the outer frame portion 16 is achieved, and the etching can be completed, so that the total time for etching can be shortened. Therefore, it is possible to prevent the floating structure 2 from being over-etched by the etching in step S6.

  In addition, it is preferable that the 1st area | region 17 is arrange | positioned avoiding the area | region which overlaps the side of the floating structure 2 among the support beam parts 15. FIG. In step S <b> 6, the place where the support beam portion 15 is divided by etching is a place that is not covered by the floating structure 2. Therefore, in order to shorten the etching time, it is preferable that the first region 17, which is a region where the support beam portion 15 is thinned in advance, coincide with a place not covered with the floating structure 2. In other words, as described above, the first region 17 is preferably arranged so as to avoid a region of the support beam 15 that overlaps the side of the floating structure 2. As shown in FIGS. 11 and 12, the present embodiment shows an example in which this preferable condition is satisfied.

(Embodiment 2)
(Production method)
With reference to FIGS. 17-22, the manufacturing method of the MEMS device in Embodiment 2 based on this invention is demonstrated. The manufacturing method of the MEMS device in the present embodiment is basically the same as that described in the first embodiment, but the position of the first region 17 set in step S3 is different. In the first embodiment, the first region 17 is set in step S3 as shown in FIG. 4, but in the present embodiment, preferably, the first region 17 is shown in FIG. Is set. That is, the first region 17 is arranged so as to be spaced from the end of the portion to be the raised facing portion 5 so as to interpose the raised overhang portion 51. The raised overhang 51 is a part of the support beam 15. By etching in step S3 in this state, the first region 17 of the support beam portion 15 becomes thin, but the raised overhang portion 51 does not become thin. Further, part of the intermediate insulating layer 102 is removed by etching in step S4. As a result, the present embodiment is as shown in FIG. Raised portions 51 are provided on both sides of the raised facing portion 5. The support beam portion 15 is connected to the raised facing portion 5.

  In the present embodiment, when the etching of step S6 is started, it becomes as shown in FIG. The raised projecting portion 51 protrudes from the projection area of the mask pattern 18. When the etching in step S6 is completed, the state is as shown in FIG. The portion of the support beam 15 that was in the first region 17 was not covered with the mask pattern 18 and was thin, and has already been removed by this etching. The raised part 51 originally had the same thickness as the raised part 5 but was not covered with the mask pattern 18 and was exposed to the etching in step S6. It is thinner than part 5. Further, the mask pattern 18 is removed, as shown in FIG. The resulting MEMS device is a resonator 902. A plan view of the resonator 902 in this state is as shown in FIG. The raised facing portion 5 is covered and hidden by the floating structure 2, but the raised protruding portion 51 is not covered by the floating structure 2 and is visible.

  The structure of the MEMS device finally obtained in the present embodiment is the same as that of the MEMS device shown in the first embodiment, except that there is a raised protruding portion 51 adjacent to the raised facing portion 5. It is. In the present embodiment, the configuration in which the raised protrusions 51 are adjacent to each other on the both sides of the raised facing portion 5 with substantially the same width is shown. However, the bulking facing portion 5 is bulky on one side and the other side. The width of the raised overhang part 51 may be different. Moreover, the structure which does not have the raising overhang | projection part 51 in the other side may be sufficient as the raising overhang part 51 only in the one side of the raising opposition part 5.

(Action / Effect)
Also in this embodiment, the same effect as in the first embodiment can be obtained. Furthermore, in the present embodiment, the first region 17 is arranged so as to be spaced apart from the end of the portion to be the raised facing portion 5 so as to interpose the raised overhanging portion 51, so that the patterning in step S6 is performed. Even if the position is slightly deviated, the raised projecting portion 51 newly becomes a part of the raised facing portion 5, and thus can serve as the raised facing portion 5. In other words, the raised projecting portion 51 can serve as a margin for absorbing the patterning position shift of the raised opposing portion 5.

(Embodiment 3)
(Production method)
With reference to FIGS. 23 to 27, a method of manufacturing a MEMS device according to the third embodiment of the present invention will be described. The manufacturing method of the MEMS device in the present embodiment is basically the same as that described in the second embodiment, but the pattern etched in step S2 is different. FIG. 23 shows an enlarged view of only the region corresponding to the central raised facing portion 5 and the support beam portion 15 when patterning the first silicon layer 101 in step S2. In the present embodiment, preferably, the step S2 of patterning the first silicon layer 101 is a second region which is a portion separated from the raised facing portion 5 of the raised overhang portion 51 as shown in FIG. 52 includes a step of providing a plurality of through holes 35 in the raised facing portion 5 and a portion of the support beam portion 15 other than the second region 52 without providing the through holes. In step S <b> 4 for cutting off the connection between the raised facing portion 5 and the second silicon layer 103, the intermediate insulating layer 102 is left in the second region 52. FIG. 24 shows a perspective view of the vicinity of the raised facing portion 5 in the state where step S4 is finished in the present embodiment. Since the through hole 35 is not provided in the second region 52, when performing step S <b> 4, in the second region 52, the etching removal rate of the intermediate insulating layer 102 under the support beam portion 15 is slow. As a result, the intermediate insulating layer 102 can be left only in the second region 52. Since the through hole 35 is provided in the other part, the etching with respect to the intermediate insulating layer 102 efficiently proceeds. As a result, the intermediate insulating layer 102 is sufficiently removed except in the second region 52, and the first silicon is removed. Layer 101 and second silicon layer 103 are already separated.

  In the present embodiment, thereafter, similarly to the case described in the first embodiment, the base material 20 is pasted in step S5. The base material 20 is attached so as to be covered from the upper side in FIG. Further, the second silicon layer 103 is polished from the side opposite to the base material 20, and the second silicon layer 103 becomes thin. The second silicon layer 103 is patterned by step S6. In step S <b> 6, the floating structure 2 is formed by patterning the second silicon layer 103, but the side of the floating structure 2 that overlaps the raised facing portion 5 extends in a direction orthogonal to the support beam portion 15. Extend as direction. FIG. 25 shows a cross-sectional view in a state where the step S6 is completed and the floating structure 2 is formed. Thus, a resonator 903 as a MEMS device could be obtained. Furthermore, the place which expanded the center part in FIG. 25 is shown in FIG. Most of the raised projecting part 51 is removed from the upper surface by etching in step S6, and as a result, is lower than the raised opposing part 5. Since the second region 52 of the raised overhang 51 is covered with the intermediate insulating layer 102, in this portion, the intermediate insulating layer 102 serves as a mask for protecting the first silicon layer 101 during the etching in step S6. It becomes. As a result, in the second region 52, the first silicon layer 101 has a convex shape only in the portion covered by the intermediate insulating layer 102. However, the first silicon layer 101 is thin in a portion not covered with the intermediate insulating layer 102 even in the second region 52. FIG. 27 shows a plan view of the resonator 903 as the obtained MEMS device.

(Action / Effect)
In the present embodiment, the same effect as in the second embodiment can be obtained. Furthermore, in the present embodiment, the intermediate insulating layer 102 is left in a part between the first silicon layer 101 and the second silicon layer 103 as shown in FIG. 24 in step S4. Further, the raised facing portion 5 supported by the support beam portion 15 is not separated from the surface of the second silicon layer 103 and floats in the air, but the surface of the second silicon layer 103 using the intermediate insulating layer 102 as a leg. It will be fixed to the shape. Therefore, the raising facing portion 5 is stably supported. It is possible to prevent a situation in which the support beam portion 15 is bent by the surface tension and the raised facing portion 5 comes into contact with the second silicon layer 103.

  In the present embodiment, finally, as shown in FIGS. 25 to 27, the intermediate insulating layer 102 remains in the vicinity of the raised facing portion 5. Since it is located away from any part of the floating structure 2 in plan view, it does not hinder the torsional vibration of the floating structure 2.

(Embodiment 4)
(Constitution)
A MEMS device according to Embodiment 4 based on the present invention will be described. The MEMS device in the present embodiment is a MEMS device that can be obtained by the method for manufacturing a MEMS device described in the second embodiment. A sectional view of the resonator 902 as the MEMS device is as shown in FIG. 21, and a plan view is as shown in FIG. The resonator 902 as the MEMS device in the present embodiment is fixed relatively to the base material 20 so as to be separated from the main surface 20a and parallel to the main surface 20a. The floating structure 2 extending to the main surface 20a is fixed to the main surface 20a, and is spaced apart from the floating structure 2, while facing a part of the floating structure 2 from the side close to the main surface 20a. A portion 5 and a raised raising portion 51 that is continuous with the raised facing portion 5 and protrudes so as to protrude from the projection region of the floating structure 2 are provided.

(Action / Effect)
According to the present embodiment, a MEMS device having a structure in which the substrate surface and the lower surface of the vibration member are opposed to each other with a sufficiently narrow gap can be used.

  Since the MEMS device according to the present embodiment includes the overhanging overhanging portion 51 that protrudes so as to protrude from the projection region of the floating structure 2, the overhanging overhanging portion 51 is provided even if the patterning position in step S6 is slightly shifted. Becomes a part of the raised facing portion 5, thereby serving as the raised facing portion 5. In other words, the positional error between the floating structure 2 and the raised facing portion 5 during assembly can be absorbed by the raised projecting portion 51. Therefore, since it can be set as the structure where the raising opposing part 5 opposes reliably with respect to the floating structure 2, it is easy to manufacture and it can be set as a highly reliable MEMS device.

(Embodiment 5)
(Constitution)
A MEMS device according to Embodiment 5 based on the present invention will be described. The MEMS device in the present embodiment is a MEMS device that can be obtained by the method for manufacturing a MEMS device described in the third embodiment. A cross-sectional view of the resonator 903 as the MEMS device is as shown in FIG. 25, and a plan view is as shown in FIG. In the MEMS device according to the present embodiment, at least a part of the upper surface of the raised projecting portion 51 is covered with an intermediate insulating layer 22 as an insulating layer in a portion separated from the projection region of the floating structure 2.

(Action / Effect)
According to the present embodiment, the same effect as in the fourth embodiment can be obtained. Furthermore, in the MEMS device according to the present embodiment, at least a part of the upper surface of the raised projecting portion 51 is covered with the insulating layer in a portion separated from the projection region of the floating structure 2. In the middle of manufacturing, the raised facing portion 5 is fixed to the surface of the second silicon layer 103 using the insulating layer as a leg. Therefore, the raising facing portion 5 is stably supported. As a result, it is possible to prevent a situation in which the support beam portion 15 is bent by the surface tension and the raised facing portion 5 comes into contact with the second silicon layer 103. Therefore, the MEMS device is easy to manufacture and has high reliability. be able to.

  In each of the above embodiments, as the structure of the MEMS device, a structure in which the floating structure 2 is disposed so as to be exposed on the inner side surrounded by the outer wall portion 9 is shown. However, a space surrounded by the outer wall portion 9 is shown. A cover member may be attached so as to cover up. This cover member preferably seals the space surrounded by the outer wall portion 9 so as not to contact the floating structure 2. By attaching such a cover member, it is possible to prevent foreign matter from entering the periphery of the floating structure 2.

  In each of the above embodiments, the MEMS device based on the present invention is a resonator. However, the MEMS device based on the present invention may be other than the resonator.

  In addition, the said embodiment disclosed this time is an illustration in all the points, Comprising: It is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

  2 Floating structure, 2a, 2b, 2c (floating structure) part, 2v (uplift facing part), 4 electrode pattern, 5 lifting facing part, 6 gap, 7 lead-out wiring, 8 external connection Terminal, 9 Outer wall part, 10 Notch part, 14 Beam-like part, 15 Supporting beam part, 16 Outer frame part, 17 First region, 18 Mask pattern, 19b, 19c Member, 20 Base material, 20a Main surface, 21 Foundation Silicon layer, 22 Intermediate insulating layer, 23 Elevated silicon layer, 31 Tunnel, 35 Through hole, 51 Raised overhang, 52 Second region, 100 SOI substrate, 101 First silicon layer, 102 Intermediate insulating layer, 103 Second Silicon layer, 901, 902, 903 resonator.

Claims (6)

A substrate having a flat main surface;
A floating structure that is relatively fixed to the substrate so as to be separated from the main surface, and extends parallel to the main surface;
A MEMS device comprising a raised facing portion fixed to the main surface and spaced apart from the floating structure and facing a part of the floating structure from a side close to the main surface is manufactured. A method,
Preparing an SOI substrate laminated so as to sandwich an intermediate insulating layer between a first silicon layer and a second silicon layer;
Patterning the first silicon layer to form an outer frame portion, the raised facing portion, and a support beam portion connecting the raised facing portion and the outer frame portion;
Etching and removing the first region, which is at least part of the support beam portion, from the surface far from the second silicon layer to the middle in the thickness direction;
Cutting the connection between the raised facing portion and the second silicon layer by etching away at least a portion of the intermediate insulating layer located between the raised facing portion and the second silicon layer. When,
Attaching the base material so as to cover the outer frame portion and the raised facing portion of the first silicon layer together from the side opposite to the second silicon layer;
The floating structure is formed by patterning the second silicon layer, and the region of the support beam that is not covered by the floating structure is removed, thereby removing the raised facing portion from the outer frame. A method for manufacturing the MEMS device, including a step of separating from the part.   2. The method for manufacturing a MEMS device according to claim 1, wherein the first region is disposed so as to avoid a region overlapping with a side of the floating structure in the support beam portion.   3. The method of manufacturing a MEMS device according to claim 1, wherein the first region is arranged so as to be spaced apart from an end of a portion to be the raised facing portion so as to interpose a raised protruding portion. In the patterning process of the first silicon layer, a through hole is not provided in the second region, which is a portion separated from the raised facing portion of the raised projecting portion, and the raised facing portion and the support beam Including a step of providing a plurality of through holes in a portion of the portion other than the second region,
4. The method of manufacturing a MEMS device according to claim 3, wherein, in the step of disconnecting the connection between the raised facing portion and the second silicon layer, the intermediate insulating layer is left in the second region. A substrate having a flat main surface;
A floating structure that is relatively fixed to the substrate so as to be separated from the main surface, and extends parallel to the main surface;
A raised facing portion that is fixed to the main surface and is spaced apart from the floating structure while facing a part of the floating structure from a side near the main surface,
A MEMS device, comprising a raised overhanging portion that is continuous with the raised facing portion and protrudes so as to protrude from a projection region of the floating structure.   The MEMS device according to claim 5, wherein at least a part of the upper surface of the raised projecting portion is covered with an insulating layer at a portion separated from a projection region of the floating structure.

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