LAMINATE STRUCTURE AND METHOD FOR MANUFACTURING LAMINATE STRUCTURE

Abstract

This laminate structure (10) comprises: a frame body (20) which has a first surface (20a) and a second surface (20b) which face the directions opposite to each other in the thickness direction thereof, and which has a film body (22) supported by the frame body (20), and a hollow section (21) that is located between the film body (22) and the second surface (20b) and opens in the second surface (20b); and a lid body (30) which is attached to the frame body (20) and has a cavity (31) located on the film body (22) and an opening section (32) that communicates with the cavity (31) and is formed at a position where at least a part of the film body (22) is exposed to an outer space of the laminate structure (10). The lid body (30) includes a groove section (41A) formed in a frame body (20)-facing surface (rear surface) (30b) of the lid body (30), and the cavity (31) and the outer space of the laminate structure (10) communicate with each other through the groove section (41A).

Description

[Technical Field]

[0001] The present embodiment relates to a laminated structure in which silicon-containing materials are laminated, and a method for manufacturing the laminated structure. [Background technology]

[0002] A transducer is known as one of various MEMS (Micro Electro Mechanical Systems) manufactured using semiconductor manufacturing processes. A MEMS transducer includes a piezoelectric element and a membrane body driven by the piezoelectric element, and is housed in, for example, a portable electronic device case as a speaker or microphone (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 061805 Summary of the Invention [Problem to be solved by the invention]

[0004] MEMS membranes are formed by etching a semiconductor substrate until a membrane of the desired thickness is obtained. During this etching, membranes and hollows are simultaneously formed in the semiconductor substrate, aligned in the thickness direction of the semiconductor substrate. During this etching, a cavity may be formed in the semiconductor substrate on the opposite side of the membrane from the portion being etched (i.e., the portion where the hollow is formed). This cavity is a space reserved for installing a piezoelectric element or the like on the membrane, and is formed in another semiconductor substrate attached to the semiconductor substrate being etched.

[0005] The membrane formed by etching is very thin, meaning that during the formation of the membrane by etching, the membrane between the cavity and the etched portion becomes thin, and there is a concern that the membrane may be damaged by stress in the membrane or by the pressure difference between the cavity and the external space of the semiconductor substrate.

[0006] The present embodiment aims to provide a laminated structure capable of suppressing damage to a film body during film formation, and a method for manufacturing the laminated structure. [Means for solving the problem]

[0007] One aspect of this embodiment is a laminated structure in which a material containing silicon is laminated, the laminated structure comprising a frame having a first surface and a second surface facing in opposite directions in a thickness direction, a membrane supported by the frame, a frame positioned between the membrane and the second surface and having a hollow opening to the second surface, and a lid attached to the frame, the lid positioned on the membrane. 1st Cavity, and 1st a cover having an opening communicating with the cavity and formed at a position where at least a part of the film body is exposed to the external space of the laminated structure, the cover having a groove formed on a surface of the cover facing the frame body; a second cavity facing another membrane body; and a communication passage connecting the first cavity and the second cavity. and 1st The cavity communicates with the external space of the laminated structure.

[0008] Another aspect of this embodiment is a method for manufacturing a laminated structure in which a material containing silicon is laminated, in which a cavity formed in a lid body faces a frame body, the lid body is attached to the frame body, a support substrate is attached to the lid body, and a membrane body is formed on the frame body by etching a second surface of the frame body located opposite a first surface to which the lid body is attached, while allowing gas to flow between the cavity and the external space of the laminated structure. [Effects of the Invention]

[0009] According to the present embodiment, it is possible to provide a laminated structure and a method for manufacturing the laminated structure that can prevent damage to the film body when the film body is formed. [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1A is a top view of the laminated structure according to the first embodiment. [Figure 1B] FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A. [Figure 2A] FIG. 2A is a diagram showing one step of the method for manufacturing the laminated structure according to the first embodiment. [Figure 2B] FIG. 2B is a diagram showing one step of the method for manufacturing the laminated structure according to the first embodiment. [Figure 2C] FIG. 2C is a diagram showing one step of the method for manufacturing the laminated structure according to the first embodiment. [Figure 2D] FIG. 2D is a diagram showing one step of the method for manufacturing the laminated structure according to the first embodiment. [Figure 2E] FIG. 2E is a diagram showing one step of the method for manufacturing the laminated structure according to the first embodiment. [Figure 2F] FIG. 2F is a diagram showing one step of the method for manufacturing the laminated structure according to the first embodiment. [Figure 2G] FIG. 2G is a diagram showing one step of the method for manufacturing the laminated structure according to the first embodiment. [Figure 2H] FIG. 2H is a diagram showing one step of the method for manufacturing the laminated structure according to the first embodiment. [Figure 3A] FIG. 3A is a top view of the laminated structure according to the second embodiment. [Figure 3B] FIG. 3B is a cross-sectional view taken along line IIIB-IIIB in FIG. 3A. [Figure 4A] FIG. 4A is a diagram showing one step of the method for manufacturing the laminated structure according to the second embodiment. [Figure 4B] FIG. 4B is a diagram showing one step of the method for manufacturing the laminated structure according to the second embodiment. [Figure 4C] FIG. 4C is a diagram showing one step of the method for manufacturing the laminated structure according to the second embodiment. [Figure 4D] FIG. 4D is a diagram showing one step of the method for manufacturing the laminated structure according to the second embodiment. [Figure 5A] FIG. 5A is a diagram showing one step of the method for manufacturing the laminated structure according to the third embodiment. [Figure 5B] FIG. 5B is a diagram showing one step of the method for manufacturing the laminated structure according to the third embodiment. [Figure 5C] FIG. 5C is a diagram showing one step of the method for manufacturing the laminated structure according to the third embodiment. [Figure 5D] FIG. 5D is a diagram showing one step of the method for manufacturing the laminated structure according to the third embodiment. [Figure 6A] FIG. 6A is a top view of a laminated structure according to a fourth embodiment. [Figure 6B] FIG. 6B is a cross-sectional view taken along line VIB-VIB in FIG. 6A. [Figure 6C] FIG. 6C is a cross-sectional view taken along line VIC-VIC in FIG. 6B. [Figure 7A] FIG. 7A is a diagram showing one step of the method for manufacturing the laminated structure according to the fourth embodiment. [Figure 7B] FIG. 7B is a diagram showing one step of the method for manufacturing the laminated structure according to the fourth embodiment. [Figure 7C] FIG. 7C is a diagram showing one step of the method for manufacturing the stacked structure according to the fourth embodiment. [Figure 7D] FIG. 7D is a diagram showing one step of the method for manufacturing the laminated structure according to the fourth embodiment. [Figure 7E] FIG. 7E is a diagram showing one step of the method for manufacturing the stacked structure according to the fourth embodiment. [Figure 7F] FIG. 7F is a diagram showing a step of the method for manufacturing the stacked structure according to the fourth embodiment. [Figure 7G] FIG. 7G is a diagram showing one step of the method for manufacturing the laminated structure according to the fourth embodiment. [Figure 7H] FIG. 7H is a diagram showing one step of the method for manufacturing the stacked structure according to the fourth embodiment. [Figure 8A] FIG. 8A is a cross-sectional view of a modified example of the laminated structure according to the first embodiment. [Figure 8B]FIG. 8B is a cross-sectional view of a modified example of the laminated structure according to the second embodiment. [Figure 9A] FIG. 9A is a top view of an example of a transducer to which the laminated structure according to the fourth embodiment is applied. [Figure 9B] FIG. 9B is a cross-sectional view taken along line IXB-IXB in FIG. 9A. [Figure 9C] FIG. 9C is a cross-sectional view taken along line IXC-IXC in FIG. 9B. [Figure 10] FIG. 10 is a top view of an example of a speaker including a transducer according to this embodiment. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] The embodiments will be described with reference to the drawings. Note that the same reference numerals will be used in the drawings to designate structurally or functionally identical parts in the respective embodiments, and redundant description of these parts will be omitted.

[0012] The laminated structure according to each embodiment is a MEMS (Micro Electro Mechanical Systems) having a membrane configured to be displaceable (flexible, strainable). The laminated structure can be applied to speakers and microphones that use piezoelectric elements to control or detect the displacement (flexure, strain) of the membrane, and transducers such as pressure sensors that measure the electrical resistance of the membrane in response to the displacement (flexure, strain) of the membrane.

[0013] (First embodiment) The configuration of the laminated structure 10 according to the first embodiment will be described. FIG. 1A is a top view of a laminated structure 10 according to this embodiment, and FIG. 1B is a cross-sectional view taken along line IB-IB in FIG. 1A. As shown in FIGS. 1A and 1B, the laminated structure 10 includes a frame body 20, a lid body 30, and an air passage 40A. The frame body 20 and the lid body 30 are made of a material containing silicon (Si), for example. For ease of explanation, the direction in which the frame body 20 and the lid body 30 are arranged (in other words, the direction in which the frame body 20 and the lid body 30 are stacked on top of each other) is referred to as the Z direction, and two directions perpendicular to the Z direction and perpendicular to each other are referred to as the X direction and the Y direction.

[0014] The frame 20 has a front surface (first surface) 20a and a back surface (second surface) 20b that face in opposite directions in the Z direction. The frame 20 has, for example, a rectangular outer shape extending in the X and Y directions, and has a hollow portion (first space) 21 located between the membrane 22 and the back surface 20b and opening to the back surface 20b. This hollow portion 21 is formed by the inner surface 20c of the frame 20. The frame 20 is formed using an SOI (Silicon on Insulator) wafer 50 (see FIG. 2A) that has an interlayer insulating layer 53 formed at the boundary between an active layer 51 on which the membrane 22 is formed and a support layer 52 on which the hollow portion 21 is formed. Note that the wafer that constitutes the frame 20 is not limited to an SOI wafer, and may be a wafer that does not have the interlayer insulating layer 53.

[0015] The frame 20 has a membrane 22. The membrane 22 is located, for example, at the same height as the front surface 20a in the Z direction. In this case, the surface facing the lid 30 is continuous with the front surface 20a of the frame 20. The membrane 22 is supported by the frame 20 and covers at least a portion of the hollow portion 21. The membrane 22 is a thin film that extends in the X and Y directions and has a thickness (e.g., 2 to 3 μm) that allows it to be displaced (flexible, deformable) in the Z direction. The thickness of the membrane 22 may be equal to or less than the thickness of the active layer 51 of the SOI wafer.

[0016] The membrane body 22 is formed by etching the back surface 20b of the frame body 20, and is supported by the inner surface 20c that forms the hollow portion 21 between the hollow portion 21 formed by etching and the cavity (second space) 31 of the lid body 30, and is formed integrally with the frame body 20. In addition, the outer edge 22a of the membrane body 22 is supported by the frame body 20 over the entire periphery. Alternatively, as will be described later, only a part of the outer edge 22a of the membrane body 22 may be supported by the frame body 20.

[0017] The lid 30 is attached to the front surface 20a of the frame 20 and is integrated with the frame 20. The lid 30 also has a cavity 31 located above the membrane 22. The lid 30 has an opening 32 formed in the front surface 30a of the lid 30 and an opening 33 formed in the back surface 30b of the lid 30, which communicate with the cavity 31. That is, the cavity 31 penetrates the lid 30 in the Z direction. The opening 32 is formed in a position where at least a portion of the membrane 22 is exposed to the external space of the laminated structure 10. In other words, when viewed from the Z direction, the opening 32 and the membrane 22 are positioned so that at least a portion of each other overlap. The opening area of the opening 32 is smaller than the area of the membrane 22, and the opening area of the opening 33 is larger than the area of the membrane 22. Like the frame 20, the lid 30 may also be formed from a silicon wafer.

[0018] The cavity 31 communicates with the external space of the laminated structure 10 via the groove 41A. In this embodiment, the cavity 31 communicates with the external space of the laminated structure 10 via the groove 41A and the ventilation path 40A. The groove 41A is formed on the surface (hereinafter referred to as the back surface) 30b of the lid 30 facing the front surface 20a of the frame 20, and is open to the front surface 20a and the cavity 31. As shown in FIG. 1B, the groove 41A extends from the cavity 31 along the back surface 30b of the lid 30 to a predetermined position within the back surface 30b. In other words, the groove 41A does not reach the side surface 30c of the lid 30. Furthermore, the ventilation path 40A extends from this predetermined position to the back surface 20b of the frame 20 and opens to the back surface 20b. In other words, the ventilation path 40A penetrates the frame 20 in the Z direction.

[0019] Next, a method for manufacturing the laminated structure 10 according to this embodiment will be described. 2A to 2H are diagrams showing the main steps of the manufacturing method according to this embodiment. The laminated structure 10 is manufactured using a frame 20, a lid 30, and a support substrate 60. The frame 20 and the lid 30 are made of separate silicon wafers. The silicon wafer constituting the frame 20 is assumed to be the SOI wafer described above. Furthermore, the lid 30 has a cavity 31 and a groove 41A formed in advance by microfabrication such as etching. Depending on the application of the laminated structure 10, various processes such as the formation of elements such as piezoelectric elements, electrodes, and wiring layers, ion implantation, and the formation or removal of resists, protective films, etc. are appropriately performed.

[0020] 2A and 2B, the active layer 51 is etched from the front surface 20a of the frame body 20 to form the bottomed holes 42 that will become part of the ventilation paths 40A (step SA1). This etching is performed until the bottomed holes 42 reach a predetermined depth (for example, a depth that reaches the interlayer insulating layer 53). Note that if an SOI wafer is not used, this step may be omitted.

[0021] 2C and 2D, the lid 30 is attached to the front surface 20a of the frame 20 with the opening 33 of the cavity 31 facing the frame 20 (step SA2). At this time, the lid 30 is positioned relative to the frame 20 so that the groove 41A is located at the position of the bottomed hole 42. Next, the support substrate 60 is attached to the front surface 30a of the lid 30 (step SA3).

[0022] An adhesive member 61 such as an adhesive tape is provided on the support substrate 60, and the support substrate 60 supports the lid 30 via this adhesive member 61. At this time, the opening 32 of the cavity 31 is closed by the support substrate 60, and the flow of gas between the cavity 31 and the external space of the laminated structure 10 is restricted.

[0023] 2E, before forming the membrane body 22, the back surface 20b of the frame body 20 is etched at a portion corresponding to the groove portion 41A (or the bottomed hole 42 if step SA1 is performed) to form the ventilation path 40A (step SA4). The formation of the ventilation path 40A connects the cavity 31 to the external space of the laminated structure 10, allowing gas to flow between them.

[0024] 2F and 2G, a region 23 (see FIG. 2E) corresponding to the cavity 31 on the rear surface 20b of the frame 20 is etched (step SA5). The etching is continued until the film thickness of the film 22 reaches a desired value (in other words, until the depth of the hollow portion 21 in the Z direction reaches a desired value). For example, the etching is continued until the interlayer insulating layer 53 is exposed in the hollow portion 21 or until the interlayer insulating layer 53 is removed.

[0025] During the etching in step SA5, there is a concern that the pressure difference between the cavity 31 and the etching atmosphere may become excessive. However, in this embodiment, gas is allowed to flow between the cavity 31 and the space outside the laminated structure 10 via the groove portion 41A and the ventilation path 40A. This reduces the pressure difference between the cavity 31 and the space outside the laminated structure 10, making it possible to prevent damage to the film 22 due to an excessive pressure difference during the formation of the film 22. As a result, the film thickness of the film 22 can be made thinner than conventional values, or the area of the film 22 can be increased.

[0026] 2H, the support substrate 60 is removed from the lid 30 (step SA6), completing the manufacturing process according to this embodiment. Even when the support substrate 60 is removed from the lid 30, the flow of gas between the cavity 31 and the external space of the laminated structure 10 is permitted via the ventilation path 40A. Therefore, even in the process of step SA6, damage to the film body 22 can be suppressed, and the support substrate 60 can be safely removed.

[0027] (Second embodiment) The configuration of the laminated structure 10 according to the second embodiment will be described. Fig. 3A is a top view of the laminated structure 10 according to the second embodiment, and Fig. 3B is a cross-sectional view taken along line IIIB-IIIB in Fig. 3A. As shown in these figures, in the second embodiment, a groove 41B is formed instead of the groove 41A. In this embodiment, the cavity 31 communicates with the external space of the laminated structure 10 via the groove 41B.

[0028] As in the first embodiment, the groove 41B according to the second embodiment is formed on the back surface 30b of the lid 30. However, as shown in FIG. 3B, the groove 41B extends from the cavity 31 to the external space of the laminated structure 10. That is, the groove 41B opens to the side surface 30c of the lid 30 and forms an air passage 40B. In other words, the air passage 40B is formed only in the lid 30. Like the air passage 40A, the air passage 40B also allows gas to flow between the cavity 31 and the external space of the laminated structure 10 when the membrane 22 is formed.

[0029] Next, a method for manufacturing the laminated structure 10 according to this embodiment will be described. 4A to 4D are diagrams showing main steps of the manufacturing method according to this embodiment. The manufacturing method according to this embodiment is generally the same as the manufacturing method according to the first embodiment. That is, as shown in FIG. 4A, with the opening 33 of the cavity 31 facing the frame body 20, the lid body 30 is attached to the front surface (first surface) 20a of the frame body 20 (step SB1), and then the support substrate 60 is attached to the front surface 30a of the lid body 30 (step SB2).

[0030] Next, as shown in FIGS. 4B and 4C, an area 23 corresponding to the cavity 31 is etched on the rear surface (second surface) 20b of the frame body 20 (step SB3). The process of step SB3 is the same as the process of step SA5. After the membrane body 22 is formed by etching in step SB3, the support substrate 60 is removed from the lid body 30 as shown in FIG. 4D (step SB4). The process of step SB4 is the same as the process of step SA6.

[0031] In the process of step SB2, the opening 32 of the cavity 31 is closed by the support substrate 60. However, because the groove portion 41B is formed in advance in the lid body 30, the flow of gas between the cavity 31 and the space outside the laminated structure 10 is maintained in a permitted state. Therefore, compared to the manufacturing method according to the first embodiment, the manufacturing method according to the second embodiment can omit the processes of step SA1 for forming the bottomed hole 42 in the frame body 20 and step SA3 for forming the ventilation path 40A.

[0032] In addition, as with the first embodiment, the manufacturing method of this embodiment can also suppress damage to the membrane 22 due to excessive pressure differences during the formation of the membrane 22, and can make the film thickness of the membrane 22 thinner than conventional values, or can increase the area of the membrane 22.

[0033] (Third embodiment) A method for manufacturing the laminated structure 10 according to the third embodiment will be described. The laminated structure 10 according to this embodiment does not have the groove 41B of the first embodiment or the groove 41B of the second embodiment. Instead, in the manufacturing method according to the third embodiment, an adhesive member 61 and a gap 62 are provided between the front surface 30a of the lid 30 and the support substrate 60, and while the support substrate 60 is supporting the lid 30, the gap 62 ensures the flow of gas between the cavity 31 and the space outside the laminated structure 10. In other words, the gap 62 functions as the air passage 40C similar to the air passage of the first or second embodiment.

[0034] 5A to 5D are diagrams showing main steps of the manufacturing method according to this embodiment. Note that FIGS. 5B to 5D are views taken from the SS cross section in FIG. 5A. As shown in FIG. 5A, an adhesive member 61 and a gap 62 serving as an air passage 40C are provided between the front surface 30a of the lid body 30 and the support substrate 60. The gap 62 is formed so as to communicate from the cavity 31 to the external space of the laminated structure, and extends, for example, in the X direction. Furthermore, as shown in FIGS. 5B and 5C, when the membrane body 22 is formed, gas is released from the cavity 31 through the gap 62, thereby suppressing an increase in the internal pressure of the cavity 31.

[0035] The other steps are the same as those in the manufacturing method according to the first or second embodiment. Therefore, in the manufacturing method according to the third embodiment, the step of forming the ventilation channel 40A in the laminated structure 10 can be omitted. Furthermore, in this embodiment, the same effects as in the first embodiment described above can be obtained.

[0036] (Fourth embodiment) The configuration of the laminated structure 10 according to the fourth embodiment will be described. In the laminated structure 10 according to each of the first to third embodiments, the entire periphery of the outer edge 22a of the membrane 22 is supported by the frame 20. On the other hand, in the present embodiment, only a portion of the outer edge 22a of the membrane 22 is supported by the frame 20. That is, the membrane 22 can function as a so-called cantilever.

[0037] FIG. 6A is a top view of the laminated structure 10 according to the fourth embodiment, and FIG. 6B is a cross-sectional view taken along line VIB-VIB in FIG. 6A. FIG. 6C is a cross-sectional view taken along line VIC-VIC in FIG. 6B. As shown in FIGS. 6A and 6B, the ventilation path 40A includes a groove 41B formed in the rear surface 30b of the lid 30, and communicates between the cavity 31 and the external space of the laminated structure 10 via the groove 41B. The ventilation path 40A also extends from the groove 41B to the rear surface 20b of the frame 20 and opens to the rear surface 20b. That is, the configuration of the ventilation path 40A of this embodiment is the same as that of the first embodiment.

[0038] As shown in Fig. 6C, a slit 25 is formed in part of the outer periphery of the membrane 22 on the frame 20 (front surface 20a of the frame 20). The slit 25 forms the outer edge 22a of the membrane 22, and is formed so that only a part of the outer edge 22a of the membrane 22 is supported by the frame 20. For example, if the membrane 22 has a rectangular shape extending in the X and Y directions, only one side of the total four outer edges extending in the X or Y direction is supported by the frame 20. In other words, the membrane 22 is configured as a cantilever that is flexible in the Z direction.

[0039] Compared to when the entire periphery of the membrane 22 is supported by the frame 20, the membrane 22 of this embodiment is more likely to be displaced in the Z direction for the same film thickness. Therefore, for example, when the membrane 22 is driven by a piezoelectric element, the voltage applied to the piezoelectric element can be reduced. Furthermore, when detecting the displacement of the membrane 22 due to a change in external force, the sensitivity of the membrane 22 to the external force is improved.

[0040] Next, a method for manufacturing the laminated structure 10 according to this embodiment will be described. The manufacturing method of this embodiment can be applied to each of the manufacturing methods of the first to third embodiments, except that the manufacturing method of this embodiment includes the step of forming the slits 25 described above.

[0041] 7A to 7H are diagrams showing main steps of the manufacturing method according to this embodiment. For convenience of explanation, these figures show an example in which the manufacturing method according to the first embodiment is applied, in which the air passage 40A is formed. That is, as shown in FIGS. 7A and 7B, before the film body 22 is formed, the active layer 51 is etched from the front surface 20a of the frame body 20 to form the slits 25 and the bottomed holes 42 (step SC1). This etching is carried out until it reaches a depth equal to or greater than the film thickness of the film body 22.

[0042] 7C and 7D, the lid 30 is attached to the front surface 20a of the frame 20 with the opening 33 of the cavity 31 facing the frame 20 (step SC2). At this time, the lid 30 is positioned relative to the frame 20 so that the groove 41A is located at the position of the bottomed hole 42 and so that the inner circumferential surface of the cavity 31 is out of alignment with the opening surface of the slit 25. Furthermore, the support substrate 60 is attached to the front surface 30a of the lid 30 (step SC3).

[0043] 7E, the back surface 20b of the frame 20 is etched in a portion corresponding to the groove 41A to form the ventilation path 40A (step SC4). The formation of the ventilation path 40A connects the cavity 31 to the external space of the laminated structure 10, allowing gas to flow between them.

[0044] Next, as shown in FIGS. 7F and 7G, an area 23 (see FIG. 2E) corresponding to the cavity 31 on the back surface 20b of the frame 20 is etched (step SC5). Etching is continued until the film thickness of the film 22 reaches the desired value (in other words, until the depth of the hollow portion 21 in the Z direction reaches the desired value). Note that the process of step SC1 has already formed a slit 25 having a depth equal to or greater than the desired film thickness of the film 22. Therefore, when the film 22 and the hollow portion 21 having the desired film thickness are formed by etching in step SC5, the slit 25 communicates with the hollow portion 21, and the outer edge 22a of the film 22 is supported by the frame 20 at only one point.

[0045] During the etching in step SC5, gas is allowed to flow between the cavity 31 and the space outside the laminated structure 10 via the ventilation path 40A. Similar to the effects obtained in each of the above-described embodiments, breakage during the formation of the film body 22 is suppressed, and the film thickness of the film body 22 can be made thinner than the conventional value, or the area of the film body 22 can be increased.

[0046] 7H, the support substrate 60 is removed from the lid 30 (step SC6), completing the manufacturing process according to this embodiment. At this time, damage to the film 22 can be suppressed, and the support substrate 60 can be safely removed.

[0047] (Variation) Fig. 8A is a cross-sectional view of a laminated structure 10 showing a modified example of the first embodiment, and is a view corresponding to Fig. 1B. Fig. 8B is a cross-sectional view of a laminated structure 10 showing a modified example of the second embodiment, and is a view corresponding to Fig. 3B. As shown in these figures, the air passage 40A or the air passage 40B may be blocked by a filler member 43. The filler member 43 is a metal paste or a resin paste, which is filled into the air passage 40A or the air passage 40B and hardened.

[0048] By blocking the air passage 40A (40B) with the filling member 43, it is possible to prevent foreign matter from entering the cavity 31. In addition, it is possible to suppress disturbances caused by the flow of gas through the air passage 40A (40B) in response to the movement (vibration or displacement) of the membrane body 22.

[0049] The lid body 30 according to the first to fourth embodiments does not need to have the opening 32. That is, the cavity 31 is formed so as to open via the opening 33. The cavity 31 and the membrane body 22 located thereunder (and the piezoelectric element 81 in the application example) are covered by the front surface 30a of the lid body 30.

[0050] (Application example) An example will be described in which the laminated structure 10 according to each of the above-described embodiments is applied to a transducer 80. This transducer 80 constitutes, for example, a speaker 90 (see FIG. 10) described below.

[0051] Fig. 9A is a top view of transducer 80, Fig. 9B is a cross-sectional view taken along line IXB-IXB in Fig. 9A, and Fig. 9C is a cross-sectional view taken along line IXC-IXC in Fig. 9B. As shown in these figures, transducer 80 employs the laminated structure 10 of the fourth embodiment shown in Fig. 6A.

[0052] 9B, the transducer 80 includes a piezoelectric element 81. The piezoelectric element 81 is placed on the film 22 so as to face the opening 33 of the lid 30. Note that a portion of the piezoelectric element 81 may straddle the connection between the film 22 and the frame 20. In either case, the entire piezoelectric element 81 faces the opening 33 of the lid 30.

[0053] The piezoelectric element 81 includes a pair of electrodes 82, 84, and a piezoelectric film 83 sandwiched between the pair of electrodes 82, 84. The pair of electrodes 82, 84 and the piezoelectric film 83 have shapes corresponding to the shape of the film body 22.

[0054] An electrode 82, a piezoelectric film 83, and an electrode 84 are laminated in this order on the film body 22 along the direction from the film body 22 toward the opening 32 (Z direction). The piezoelectric element 81 is formed on the film body 22 before the lid body 30 is attached to the frame body 20 (before the bottomed hole 42 and the slit 25 are formed, if any). When a drive voltage is applied between the pair of electrodes 82, 84, the film body 22 is displaced due to expansion and contraction of the piezoelectric film 83. Specifically, the tip side of the film body 22 is displaced so as to warp along the Z direction.

[0055] By repeatedly applying a drive voltage to the pair of electrodes 82, 84, the film 22 alternately repeats displacement toward the hollow portion 21 side and toward the cavity 31 side. This vibration of the film 22 vibrates the air around the film 22, generating sound waves. These sound waves propagate through the opening 32 of the cavity 31 into the space outside the transducer 80 (laminated structure 10).

[0056] The electrodes 82 and 84 are formed of a thin conductive metal film such as platinum, molybdenum, iridium, or titanium. The electrode 82 is located on the upper surface of the piezoelectric film 83 and is connected to a wiring 86. The electrode 84 is located on the lower surface of the piezoelectric film 83 and is connected to a wiring 88.

[0057] The piezoelectric film 83 is made of, for example, lead zirconate titanate (PZT), but may also be made of aluminum nitride (AlN), zinc oxide (ZnO), lead titanate (PbTiO3), or the like.

[0058] A plurality of the above-described transducers 80 may be arranged. The plurality of transducers 80 are arranged in a line or in a matrix. Figures 10 to 12 show an example of a speaker 90 including a plurality of transducers 80, 80, 80 arranged in a line. Figure 10 is a top view of the speaker 90, Figure 11 is a cross-sectional view taken along line XI-XI in Figure 10, and Figure 12 is a cross-sectional view taken along line XII-XII in Figure 11.

[0059] As shown in Figures 10 to 12, each of the lids 30 for the three transducers 80 is formed as a single structure. Furthermore, a partition wall 30d between two adjacent ones of the three transducers 80 is provided with a communication passage 91 that connects the respective cavities 31 (in other words, the first cavity and the second cavity). This communication passage 91 is formed as a groove in the back surface 30b of the lid 30 that constitutes each transducer 80. The communication passage 91 allows gas to flow between the two adjacent cavities 31.

[0060] As shown in Fig. 11, speaker 90 has a single groove 41A and an air passage 40A communicating therewith. Note that speaker 90 may also have a single groove 41B (air passage 40B) (see Fig. 3B). In either case, groove 41A and air passage 40A or air passage 40B are provided at the end of an array of multiple transducers 80, as shown in Fig. 10, for example, and communicate between cavity 31 of transducer 80 closest to that end and the space outside transducer 80.

[0061] 9A to 9C, except for the above-mentioned communication path 91 and the fact that a single air passage 40A (40B) is shared by multiple transducers 80. That is, each transducer 80 includes a membrane 22 and a piezoelectric element 81 as a sound wave generating source.

[0062] 12, the communication passage 91 spatially connects the cavities 31 of each transducer 80. Therefore, when manufacturing a plurality of laminated structures 10 arranged in one direction (i.e., a plurality of transducers 80 constituting a speaker 90), by providing a single air passage 40A (40B) shared by these, the number of laminated structures 10 (transducers 80) manufactured per wafer can be increased. Furthermore, it is possible to suppress breakage during the formation of the film body 22 obtained in each embodiment, to make the film body 22 thinner, and to increase the area of the film body 22. [Explanation of symbols]

[0063] 10. Laminated structure 20 Frame 20a Front (first side) 20b Back (2nd side) 20c inner surface 21 Hollow part (hollow) 22 Membrane body 22a outer edge 23 areas 25 slit 30 Lid 30a front 30b back 30c side 30d partition wall 31 Cavity 32 Opening 33 Opening 40A Ventilation Channel 40B Ventilation channel 40C Ventilation Channel 41A Groove 41B Groove 42 Bottomed hole 43 Filler material 50 wafers 51 Active layer 52 Support layer 53 Interlayer insulating layer 60 Support substrate 61 Adhesive material 62 Gap 80 transducers 81 Piezoelectric element 82 electrode 83 Piezoelectric film 84 electrode 86 Wiring 88 Wiring 90 Speaker 91 Communication path

Claims

1. A laminated structure in which a material containing silicon is laminated, a frame having a first surface and a second surface facing in opposite directions in a thickness direction, the frame having a membrane supported by the frame, and a hollow portion located between the membrane and the second surface and opening to the second surface; a lid attached to the frame, the lid having a first cavity located above the membrane and an opening communicating with the first cavity and formed at a position where at least a portion of the membrane is exposed to an external space of the laminated structure; the lid body includes a groove portion formed on a surface of the lid body facing the frame body, a second cavity facing another membrane body, and a communication passage connecting the first cavity and the second cavity, the first cavity communicates with an external space of the laminated structure via the groove portion; Laminated structure.

2. the first cavity communicates with an external space of the laminated structure through an air passage that communicates with the groove and passes through the frame; The laminated structure according to claim 1 .

3. The groove portion extends from the first cavity to an external space of the laminated structure. The laminated structure according to claim 1 .

4. A slit formed on the first surface of the frame at the outer periphery of the film body. Further comprising: The laminated structure according to any one of claims 1 to 3.

5. The outer edge of the membrane is supported by the frame only in part. The laminated structure according to any one of claims 1 to 4.

6. The outer edge of the membrane body is supported by the frame body around the entire periphery. The laminated structure according to any one of claims 1 to 3.

7. The ventilation passage is blocked by a filling member. The laminated structure according to claim 2 .

8. The groove portion is filled with a filling member. The laminated structure according to claim 3 .

9. a piezoelectric element disposed on the membrane in the first cavity of the lid; Further comprising: The laminated structure according to any one of claims 1 to 8.

10. The material of the lid includes silicon. The laminated structure according to any one of claims 1 to 9.

11. A method for manufacturing a laminated structure in which a material containing silicon is laminated, comprising the steps of: attaching the lid to the frame in a state where the cavity formed in the lid faces the frame; a support substrate attached to the lid; a second surface of the frame body facing in a direction opposite to the first surface to which the lid body is attached in a thickness direction of the frame body, the second surface being etched while allowing a gas to flow between the cavity and the external space of the laminated structure, to form a membrane body on the frame body; A method for manufacturing a laminated structure.

12. the lid body includes a groove portion formed on a surface of the lid body facing the frame body, Before forming the membrane body, an air passage is formed that communicates with the cavity from the second surface of the frame body via the groove portion. The method for producing the laminated structure according to claim 11 .

13. the lid body includes a groove portion formed on a surface of the lid body facing the frame body, The groove portion extends from the cavity to the external space of the laminated structure. The method for producing the laminated structure according to claim 11 .

14. The cavity of the lid body is open toward the support substrate. A method for producing the laminated structure according to any one of claims 11 to 13.

15. the cavity of the lid body is open toward the support substrate, An adhesive member and a gap communicating from the cavity to an external space of the laminated structure are provided between the lid and the support substrate. The method for producing the laminated structure according to claim 11 .

16. Before forming the film body, a slit is formed in a part of the outer periphery of the frame body in the region where the film body is to be formed. A method for producing the laminated structure according to any one of claims 11 to 15.

Images