MEMS Module and Method for Manufacturing the Same

Abstract

To provide a MEMS module capable of deriving a change of external air pressure with sufficient accuracy, and a method of manufacturing the MEMS module.SOLUTION: A MEMS module A1 includes: a MEMS element 3 provided with a substrate 30 in which a hollow portion 360 is formed, the MEMS element 3 including a movable portion 340, which is a portion of the substrate 30, around the hollow portion 360, the movable portion 340 having a thickness whose shape is changeable by an air pressure difference between an internal air pressure inside the hollow portion 360 and an external air pressure outside the substrate 30; and an electronic component 2, to which an output signal of the MEMS element 3 is input, formed on the substrate 30. The electronic component 2 and the MEMS element 3 are spaced apart from each other in a direction perpendicular to a thickness direction of the movable portion 340.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This embodiment relates to a MEMS module and a method for manufacturing the same.

Background Art

[0002] A MEMS (Micro Electro Mechanical System) element, which is a device integrating mechanical element parts and an electronic circuit using microfabrication technology used in the manufacture of semiconductor integrated circuits, is known.

[0003] The MEMS element has a hollow portion and a movable portion that closes the hollow portion. In the configuration disclosed in Patent Document 1, the hollow portion is formed by bonding a glass substrate to the back side of a Si substrate in which a recess is formed. In this bonding, when the hollow portion is sealed, it is required that no fine gap is generated. Further, when the movable portion is finished as a relatively thin portion, it is necessary to deeply dig the Si substrate to form the recess.

[0004] In addition, the MEMS element may be incorporated into a pressure sensor and used. The pressure sensor changes the stress generated at the end of the movable portion of the MEMS element due to a change in the external air pressure, the gauge resistance changes according to the deformation of the movable portion, and the change in the gauge resistance is output as a change in the output voltage.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the pressure sensor may cause a change in the gauge resistance not only due to a change in the external air pressure but also due to an external stress transmitted to the movable part (also referred to as a membrane) of the MEMS element. Since the above output voltage changes due to factors other than the change in the external air pressure, it may be difficult to accurately detect the change in the external air pressure. One aspect of the present embodiment provides a MEMS module capable of accurately deriving a change in the external air pressure. Another aspect of the present embodiment provides a method for manufacturing the MEMS element.

Means for Solving the Problem

[0007] In the present embodiment, by providing a MEMS element and an electronic component into which the output signal of the MEMS element is input on the same substrate, stress caused by factors other than the change in the external air pressure applied to the MEMS element can be suppressed. One aspect of the present embodiment is as follows.

[0008] One aspect of the present embodiment is that inside Sealed around a substrate in which a hollow portion is formed Formed in a MEMS element, Inside the substrate the hollow portion Arranged adjacent to having a movable part, the movable part having a thickness that can be deformed in shape by the pressure difference between the pressure inside the hollow portion and the pressure outside the substrate, a MEMS element, and an electronic component formed on the substrate and into which the output signal of the MEMS element is input, A printed circuit board, and a stress relaxation material disposed between the printed circuit board, the MEMS element, and the substrate including the electronic component and the electronic component and the MEMS element are separated from each other in a direction perpendicular to the thickness direction of the movable part, a MEMS module.

[0009] Also, another aspect of the present embodiment is A method for manufacturing a MEMS module according to an aspect of the above-described embodiment, wherein the forming a plurality of groove portions in a semiconductor layer included in a substrate, etching the semiconductor layer in a direction perpendicular to the depth direction of the groove portions from the bottom surface of the groove portions to connect the plurality of groove portions, performing heat treatment on the semiconductor layer, and a part of the semiconductor layer melted by the heat treatment closing the groove portions to form Sealed around having a hollow portion The forming a MEMS element, and inputting the output signal of the MEMS element to the substrateThe A method for manufacturing a MEMS module, which forms an electronic component, and in a direction perpendicular to the depth direction of the groove portion, the electronic component and the MEMS element are spaced apart from each other.

[0010] Another aspect of the present embodiment is A method for manufacturing a MEMS module according to an aspect of the above-described embodiment, preparing a first substrate including a semiconductor layer and a second substrate on which a semiconductor layer is laminated, forming a portion on the first substrate, and The on the first substrate on which the portion is formed, joining the second substrate, and forming a MEMS element having a hollow portion in the portion formed on the first substrate, Groove forming an electronic component into which the output signal of the MEMS element is input on the second substrate, and in a direction perpendicular to the depth direction of the groove portion, the electronic component and the MEMS element are spaced apart from each other. A method for manufacturing a MEMS module. Groove Of the semiconductor layer Groove Sealed around The Remove the oxide film of the second substrate, 2 The

[0011]

Advantages of the Invention

[0011] According to the present embodiment, it is possible to provide a MEMS module capable of accurately deriving a change in external atmospheric pressure. In addition, it is possible to provide a method for manufacturing the MEMS module.

Brief Description of the Drawings

[0012]

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Best Mode for Carrying Out the Invention

[0013] Next, this embodiment will be described with reference to the drawings. In the descriptions of the drawings below, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationships such as the thickness and planar dimensions of each component are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. Also, it goes without saying that there are portions where the dimensional relationships and ratios are different between the drawings.

[0014] In addition, the embodiments shown below illustrate devices and methods for embodying the technical idea, and do not specify the materials, shapes, structures, arrangements, etc. of each component. Various modifications can be made to this embodiment within the scope of the claims.

[0015] One aspect of the specific embodiment is as follows.

[0016] <1> A MEMS element including a substrate having a hollow portion formed therein, the MEMS element having a movable portion which is a part of the substrate around the hollow portion, the movable portion having a thickness such that its shape can be deformed by a pressure difference between the pressure inside the hollow portion and the pressure outside the substrate, and an electronic component formed on the substrate and to which an output signal of the MEMS element is input, wherein the electronic component and the MEMS element are separated from each other in a direction perpendicular to the thickness direction of the movable portion. A MEMS module.

[0017] <2> The MEMS module according to <1>, wherein in the substrate, there is a groove portion extending in the thickness direction of the substrate from the main surface of the substrate between the MEMS element and the electronic component.

[0018] <3> The MEMS module according to <2>, further comprising a first wiring having a region located on the outer edge side of the substrate from the end of the groove portion in a direction perpendicular to the direction in which the electronic component and the MEMS element are separated from each other and the thickness direction of the movable portion, wherein the MEMS element and the electronic component are electrically connected to the first wiring.

[0019] <4> The MEMS module according to any one of <1> to <3>, further comprising a protective film having an opening on the substrate, the protective film covering at least a part of the electronic component, and the opening being above the movable portion when viewed from the thickness direction of the movable portion.

[0020] <5> The MEMS module according to any one of <1> to <4>, further comprising a printed circuit board and a stress relaxation material disposed between the printed circuit board and the MEMS element, wherein the thickness of the stress relaxation material is 35 to 80 μm.

[0021] <6> The MEMS module according to <5>, further comprising a second wiring electrically connecting the printed circuit board and the electronic component, and the second wiring is electrically connected to the electronic component on the side opposite to the side where the MEMS element is located.

[0022] <7> The MEMS module according to any one of <1> to <6>, wherein the substrate is made of silicon.

[0023] <8> Form a plurality of grooves in the semiconductor layer included in the substrate, etch the semiconductor layer in a direction perpendicular to the depth direction of the groove from the bottom surface of the groove to connect the plurality of grooves, perform heat treatment on the semiconductor layer, and a part of the semiconductor layer melted by the heat treatment closes the groove to form a MEMS element having a hollow portion, form an electronic component into which the output signal of the MEMS element is input on the substrate, and in a direction perpendicular to the depth direction of the groove, the electronic component and the MEMS element are separated from each other. A method for manufacturing a MEMS module.

[0024] <9> The hollow portion is formed by deep etching and isotropic etching. The method for manufacturing a MEMS module according to <8>.

[0025] <10> The heat treatment is performed at 1100 to 1200 ° C to cause a thermal migration phenomenon in the semiconductor layer to close the groove and form the hollow portion. The method for manufacturing a MEMS module according to <8> or <9>.

[0026] <11> Prepare a first substrate including a semiconductor layer and a second substrate having a semiconductor layer laminated on an oxide film, form an opening in the first substrate, bond the second substrate on the first substrate on which the opening is formed, and form a MEMS element having a hollow portion formed in the opening of the first substrate, form an electronic component into which the output signal of the MEMS element is input on the first substrate, and in a direction perpendicular to the depth direction of the groove, the electronic component and the MEMS element are separated from each other. A method for manufacturing a MEMS module.

[0027] <12> The oxide film is a silicon oxide layer. The method for manufacturing a MEMS module according to <11>.

[0028] <13> The semiconductor layer is a silicon layer. The method for manufacturing a MEMS module according to any one of <8> to <12>.

[0029] (First Embodiment) The MEMS module A1 according to this embodiment will be described.

[0030] FIG. 1 is a perspective view showing the MEMS module A1. FIG. 2 is a perspective view of the main part with the illustration of some components (such as the cover 6 and the bonding material 7 described later) of the MEMS module A1 shown in FIG. 1 omitted. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 1. The MEMS module A1 includes a substrate 1, electronic components 2, a MEMS element 3, a plurality of wirings 4, a cover 6, and a bonding material 7. The electronic components 2 and the MEMS element 3 are formed on one chip (in this embodiment, the substrate 30). The MEMS module A1 of this embodiment detects atmospheric pressure and is, for example, surface-mounted on the circuit board of various electronic devices such as mobile terminals. For example, in a mobile terminal, the MEMS module A1 detects atmospheric pressure. The detected atmospheric pressure is used as information for calculating altitude.

[0031] Also, in this embodiment, the thickness direction (plan view direction) of the MEMS module A1 is defined as the z direction (z1 - z2 direction), the direction along one side of the MEMS module A1 orthogonal to the z direction is defined as the x direction (x1 - x2 direction), and the direction orthogonal to the z direction and the x direction is defined as the y direction (y1 - y2 direction). In this embodiment, the MEMS module A1 has, for example, an x-direction dimension of about 2 mm, a y-direction dimension of about 2 mm, and a z-direction dimension of about 0.8 mm to 1 mm.

[0032] The substrate 1 is a member for mounting the electronic components 2 and the MEMS element 3 and mounting the MEMS module A1 on the circuit board of various electronic devices as shown in FIG. 2 and the like. The substrate 1 has a base material 1A, a wiring portion 1B, and an insulating layer 1C as shown in FIG. 3. Note that the specific configuration of the substrate 1 is not particularly limited as long as it can appropriately support the electronic components 2, the MEMS element 3, etc., and examples include printed circuit boards and the like.

[0033] The base material 1A is made of an insulator and is a main component of the substrate 1. Examples of the base material 1A include glass epoxy resin, polyimide resin, phenolic resin, and ceramics. The base material 1A is, for example, in the shape of a rectangular plate in plan view and has a mounting surface 1a and a mounting surface 1b. The mounting surface 1a and the mounting surface 1b face opposite sides in the thickness direction (z direction) of the substrate 1. The mounting surface 1a is a surface facing the z1 direction and is a surface on which the electronic component 2 and the MEMS element 3 are mounted. The mounting surface 1b is a surface facing the z2 direction and is a surface used when mounting the MEMS module A1 on the circuit board of various electronic devices. In the present embodiment, the dimension of the substrate 1 in the z direction is about 100 to 200 μm, and the dimensions in the x direction and the y direction are each about 2 mm.

[0034] The wiring portion 1B forms a conduction path for conducting the electronic component 2 and the MEMS element 3 with a circuit or the like outside the MEMS module A1. The wiring portion 1B is made of, for example, one or a plurality of metals such as Cu, Ni, Ti, and Au, and is formed by, for example, plating. In the present embodiment, the wiring portion 1B has a plurality of mounting surface portions 100 and back surface pads 19, but these are an example of a specific configuration of the wiring portion 1B, and the configuration is not particularly limited.

[0035] The plurality of mounting surface portions 100 are formed on the mounting surface 1a of the base material 1A and are a plurality of independent regions spaced apart from each other. The mounting surface portion 100 has an electrode pad 11, and the end portion of the wiring 4 is bonded to the electrode pad 11.

[0036] The back surface pad 19 is provided on the mounting surface 1b and is used as an electrode to be conductively joined when mounting the MEMS module A1 on a circuit board or the like. The back surface pad 19 is in conduction with an appropriate position of the mounting surface portion 100.

[0037] The insulating layer 1C covers an appropriate position of the wiring portion 1B to insulate and protect the portion. The insulating layer 1C is made of an insulating material and is formed by, for example, a resist resin. The insulating layer 1C may be formed in a rectangular annular shape in plan view, for example.

[0038] The bonding material 7 bonds the substrate 1 and the cover 6, and is composed of, for example, a paste bonding material containing a metal such as Ag. In the present embodiment, the bonding material 7 is provided in a rectangular ring shape in plan view, and a part of the bonding material 7 is formed in a region overlapping the insulating layer 1C.

[0039] The electronic component 2 processes the electrical signals detected by the sensor, and is configured as a so-called ASIC (Application Specific Integrated Circuit) element. The electronic component 2 may include, for example, a temperature sensor, and processes the electrical signals detected by the temperature sensor and the electrical signals detected by the MEMS element 3. The electronic component 2 multiplexes the electrical signals detected by the temperature sensor and the electrical signals detected by the MEMS element 3 with a multiplexer, and converts them into digital signals with an analog / digital conversion circuit. Then, the signal processing unit performs processes such as amplification, filtering, and logical operation while using the storage area of the storage unit based on the clock signal. The signal after signal processing is output via the interface. Thereby, the MEMS module A1 can output the signals detecting the atmospheric pressure and the atmospheric temperature after performing appropriate signal processing.

[0040] The electronic component 2 is for controlling various elements mounted on a substrate and packaged. As shown in FIGS. 3 to 5, the electronic component 2 has a substrate 30 that is rectangular plate-shaped in plan view and has a main surface 2a and a mounting surface 2b. The main surface 2a and the mounting surface 2b face opposite sides in the thickness direction (z direction) of the substrate 30. In the present embodiment, the dimension of the electronic component 2 in the z direction is the same as that of the MEMS element 3, for example, about 200 to 300 μm, the dimension in the x direction is the same as that of the MEMS element 3, for example, about 1 to 1.2 mm, and the dimension in the y direction is, for example, about 1 to 1.2 mm.

[0041] The electronic component 2 is mounted closer to the x1 direction on the mounting surface 1a of the substrate 1. The electronic component 2 and the substrate 1 are joined by a stress-relieving material 9 such as silicone resin and die attach film. A plurality of electrode pads 24 are provided on the main surface 2a of the electronic component 2. The electrode pads 24 are used as electrodes that are conductively joined (electrically connected) to the electrode pads 11 of the substrate 1. Wiring 4 is bonded to the electrode pads 24. The electrode pads 24 are made of a metal such as Al or an aluminum alloy, and are formed by, for example, sputtering or plating. In this embodiment, an Al layer formed by sputtering is used as the electrode pad 24. The electrode pads 24 are connected to the wiring pattern on the main surface 2a. Here, in this specification etc., "electrically connected" includes cases where it is connected via "something having some electrical action". Here, "something having some electrical action" is not particularly limited as long as it enables the transfer of electrical signals between the connection targets. For example, "something having some electrical action" includes electrodes, wirings, switching elements, resistance elements, inductors, capacitance elements, and other elements having various functions.

[0042] The electrode pads 24 are provided on the main surface 2a of the electronic component 2 on the side opposite to the side where the MEMS element 3 is located (the y2 direction side of the electronic component 2), and the wiring 4 is bonded thereto. The wiring 4 is protected by the resin 8. By providing the wiring 4 protected by the resin 8 on the main surface 2a on the y2 direction side of the main surface 2a of the electronic component 2, the bonding location of the wiring 4 can be moved away from the movable part 340 of the MEMS element 3, and thereby, the influence of the stress by the resin 8 on the movable part 340 can be suppressed.

[0043] The MEMS element 3 is configured as a pressure sensor for detecting atmospheric pressure. The MEMS element 3 detects atmospheric pressure and outputs the detection result as an electrical signal to the electronic component 2. As shown in FIGS. 3 to 5, the MEMS element 3 includes a substrate 30 having a main surface 3a and a mounting surface 3b. The main surface 3a and the mounting surface 3b face opposite sides in the thickness direction (z direction) of the substrate 30. The main surface 3a is a surface facing the z1 direction. The mounting surface 3b is a surface facing the z2 direction and is the surface used when mounting the MEMS element 3 on the substrate 1. In the present embodiment, the dimension of the MEMS element 3 in the z direction is the same as that of the electronic component 2, for example, about 200 to 300 μm, the dimension in the x direction is the same as that of the electronic component 2, for example, about 1 to 1.2 mm, and the dimension in the y direction is, for example, about 1 to 1.2 mm.

[0044] The MEMS element 3 and the substrate 1 are joined by a stress-relieving material 9 such as silicone resin and die attach film. Also, in the y direction, the electronic component 2 and the MEMS element 3 are spaced apart from each other.

[0045] Since the stress-relieving material 9 has the electronic component 2 and the MEMS element 3 formed on one chip (substrate 30), it can be made thick enough to suppress the influence of external stress on the movable part 340. For example, when the thickness (dimension in the z direction) of the stress-relieving material 9 is 35 μm or more, the influence of external stress on the movable part 340 can be suppressed. Also, as the thickness of the stress-relieving material 9 increases, the external stress decreases, and when it exceeds 80 μm, the external stress becomes extremely small. Therefore, the thickness (dimension in the z direction) of the stress-relieving material 9 is preferably, for example, 35 to 80 μm, and more preferably 45 to 70 μm.

[0046] The substrate 30 includes a semiconductor layer, and examples of the semiconductor layer include a silicon layer. The substrate 30 may be composed of, for example, only a silicon layer, or may be composed of a laminated film of an oxide film such as a silicon oxide layer and a silicon layer.

[0047] Inside the substrate 30, a hollow portion 360 of the MEMS element 3 is provided. Also, a part of the substrate 30 around the hollow portion 360 is the movable portion 340 of the MEMS element 3. Further, a fixed portion 370 of the MEMS element 3 is provided on the substrate 30.

[0048] The movable portion 340 overlaps the hollow portion 360 in the z direction and moves in the z direction to detect the air pressure. In the present embodiment, the movable portion 340 is rectangular when viewed from the z direction. The film thickness T of the movable portion 340 may be a thickness that can be deformed in shape by the air pressure difference between the air pressure inside the hollow portion 360 and the air pressure outside the substrate 30, and is, for example, 5 to 15 μm.

[0049] The hollow portion 360 is a cavity provided in the substrate 30 and is sealed in the present embodiment. The hollow portion 360 may be a vacuum. Also, in the present embodiment, the hollow portion 360 is rectangular when viewed in the z direction, but is not limited thereto. The depth (z-direction dimension) of the hollow portion 360 is, for example, 5 to 15 μm.

[0050] The fixed portion 370 is a portion that supports the movable portion 340 and is a portion fixed to the substrate 1 when the movable portion 340 operates. In the present embodiment, the portion of the substrate 30 other than the movable portion 340 and the hollow portion 360 is defined as the fixed portion 370.

[0051] In the present embodiment, the movable portion 340 and the fixed portion 370 are made of the same and single semiconductor without having a joint at their mutual boundary, and are made of, for example, silicon. The movable portion 340 has a recess in the region 330. The recess is located in the region of the movable portion 340 that overlaps the hollow portion 360 when viewed in the z direction and is gently recessed in the z direction.

[0052] The recessed portion is formed by a part of the substrate melted by heat treatment closing the groove portion, as will be described in the manufacturing method hereinafter. Just closing the groove portion is not enough because the film thickness T of the movable portion 340 is thin. Therefore, an interlayer film 350 may be provided on the movable portion 340 to increase the film thickness T. In the present embodiment, when the interlayer film 350 is provided, the interlayer film 350 has a region 335 that functions as a part of the movable portion 340. Thus, the movable portion 340 has the region 330 of the substrate 30 and the region 335 of the interlayer film 350. Also, the main surface 3a of the MEMS element 3 is the surface of the interlayer film 350 in the z1 direction. In this specification and the like, the "flat surface" includes a surface with an average surface roughness of 0.5 μm or less. Note that the average surface roughness can be obtained, for example, in accordance with JIS B 0601:2013 or ISO 25178. The interlayer film 350 can be made of, for example, the same material as the substrate 30 and may be made of silicon. When the interlayer film 350 is provided, the surface on which the protective film 10 is formed is a flat surface, which is preferable because the coverage of the protective film 10 is improved.

[0053] The MEMS element 3 generates an electrical signal corresponding to the shape (degree of distortion) of the movable portion 340 that deforms due to the difference between the air pressure inside the hollow portion 360 and the air pressure outside the substrate 30, and outputs the electrical signal to the electronic component 2. On the main surface 3a of the MEMS element 3, a strain gauge 320 whose resistance value changes according to the deformation of the movable portion 340 is provided.

[0054] The electronic component 2 includes a plurality of wirings 12A and a plurality of electrode layers 12B. The electrical signal generated in the MEMS element 3 is output to the electronic component 2 via the plurality of wirings 12A and the plurality of electrode layers 12B. A part of the wiring 12A is electrically connected to the electrode pad 24 of the electronic component 2, and the electrode pad 24 is electrically connected to the electrode pad 11 of the substrate 1 via the wiring 4.

[0055] Also, at least a part of the electronic component 2 and the MEMS element 3 may be covered with the protective film 10. By covering with the protective film 10, the inside of the electronic component 2 and the MEMS element 3 can be protected. Examples of the protective film 10 include resin and insulating film.

[0056] The wiring 4 electrically connects the electrode pad 11 on the substrate 1 to the electrode pad 24 of the electronic component 2, and is made of a metal such as Au. Note that the material of the wiring 4 is not limited and may be, for example, Al, Cu, etc. The wiring 4 is bonded to the electrode pad 11 and the electrode pad 24.

[0057] The cover 6 is a box-shaped member made of metal, and is joined to the mounting surface 1a of the substrate 1 by a bonding material 7 so as to surround the electronic component 2, the MEMS element 3, and the wiring 4. In the illustrated example, the cover 6 is rectangular in plan view. Note that the cover 6 may be made of a material other than metal. Also, the manufacturing method of the cover 6 is not particularly limited. The space between the cover 6 and the substrate 1 is in a state of being filled with a soft resin such as a hollow or silicone resin.

[0058] As shown in FIGS. 1 and 3, the cover 6 has an opening 61 and an extension 62. The opening 61 is for taking in outside air inside. By providing the opening 61 and being in a state of being filled with a hollow or soft resin, the MEMS element 3 can detect the air pressure (e.g., atmospheric pressure) around the MEMS module A1, and the temperature sensor of the electronic component 2 can detect the air temperature around the MEMS module A1. In the present embodiment, only one opening 61 is arranged at the position on the z1 direction side of the MEMS element 3. Note that the number of the openings 61 is not particularly limited. The extension 62 extends from the edge of the opening 61 and overlaps at least a part of the opening 61 in plan view. The extension 62 is located in the z2 direction as it moves away from the edge of the opening 61 and is inclined so as to approach the substrate 1. Also, in the illustrated configuration, the tip of the extension 62 is provided at a position avoiding the electronic component 2 and the MEMS element 3 in plan view. Also, the base of the extension 62 is provided at a position overlapping the electronic component 2 and the MEMS element 3. Note that the extension 62 may not be provided.

[0059] Next, a method for manufacturing the MEMS module A1 will be described.

[0060] First, as shown in FIG. 6, a substrate 30 including a semiconductor layer is prepared. As the semiconductor layer, for example, a silicon layer can be mentioned. The thickness of the substrate 30 is, for example, about 700 to 800 μm.

[0061] Next, as shown in FIG. 7, a plurality of groove portions 31 are formed in the substrate 30. The groove portions 31 can be formed, for example, by deep etching such as the Bosch method. As an example of the dimensions and the like of the plurality of groove portions 31, the diameter of the groove portion 31 having a circular shape in the z-direction view is 0.2 to 0.8 μm, and the pitch (center-to-center distance) between adjacent groove portions 31 is 0.4 to 1.4 μm. Also, in the present embodiment, the dimensions of the plurality of groove portions 31 in the z-direction view are substantially the same.

[0062] Next, as shown in FIG. 8, the substrate 30 is etched in a direction perpendicular to the depth direction of the groove portion 31 from the bottom surface of the groove portion 31 to form a hollow portion 360 that connects the plurality of groove portions 31 (hollow portion forming step). In the hollow portion forming step, isotropic etching is performed so that the cross-sectional area perpendicular to the z-direction gradually increases. Thereby, the step of forming the groove portion 31 and the hollow portion forming step can be continuously performed by the same process, and the hollow portion 360 can be efficiently formed.

[0063] Next, as shown in FIG. 9, the substrate 30 is heat-treated (for example, at 1100 to 1200 ° C.) in an atmosphere containing hydrogen, and a part of the substrate 30 melted by the heat treatment closes the groove portion 31. Thereby, the hollow portion 360 is sealed. At the same time, the region 330 of the substrate 30 becomes a part of the movable portion 340 (movable portion forming step). In this manufacturing method, in order to form the movable portion 340 and the hollow portion 360, a step of joining a plurality of different members is unnecessary. Thereby, there is an advantage that there is no possibility of deterioration in airtightness at the joint portion. Also, there is an advantage that it is not necessary to provide an excessive groove portion that penetrates the substrate 30, for example, in order to form the hollow portion 360.

[0064] In the movable part forming process, a plurality of grooves 31 are closed by partially moving the semiconductor layer using thermal migration. Therefore, the movable part 340 is a part composed only of the material of the semiconductor layer, and has a configuration that is integrally connected to the fixed part 370, which is also made of the material of the semiconductor layer, without passing through a joint part. Thereby, the sealing performance of the hollow part 360 can be enhanced.

[0065] Also, the movable part 340 has a recess in the region 330. In order to increase the film thickness T of the movable part 340, as shown in FIG. 10, an interlayer film 350 is formed on the main surface (recess) of the substrate 30 facing the z1 direction. The interlayer film 350 has a region 335 that functions as a part of the movable part 340. Therefore, the movable part 340 has the region 330 of the substrate 30 and the region 335 of the interlayer film 350. For the interlayer film 350, for example, a silicon layer deposited by a CVD method can be used. Due to the interlayer film 350, the surface on which the protective film 10 is formed becomes a flat surface, and the coverage of the protective film 10 is improved.

[0066] Next, as shown in FIG. 11, in a direction (y direction) perpendicular to the thickness direction of the movable part 340, a plurality of wirings 12A and a plurality of electrode layers 12B are formed inside the substrate 30 and the interlayer film 350 in a region separated from the region where the MEMS element 3 is formed. Further, a protective film 10 that covers the interlayer film 350 and the uppermost (z1 direction side) wiring 12A is formed.

[0067] Through the above processes, the electronic component 2 and the MEMS element 3 can be manufactured. Since the electronic component 2 and the MEMS element 3 are formed on one chip (substrate 30), the influence of the stress caused by the resin 8 formed later on the movable part 340 can be suppressed, and the process can be simplified. Further, since the electronic component 2 and the MEMS element 3 are not laminated, the height occupied by the electronic component 2 and the MEMS element 3 can be reduced, and the stress relaxation material 9 can be made thicker. Thereby, the influence of the external stress on the movable part 340 can be suppressed.

[0068] Next, as shown in FIG. 5, the substrate 1, the electronic component 2, and the MEMS element 3 are joined by a stress relaxation material 9. Further, a wiring 4 that electrically connects the electrode pad 11 of the substrate 1 and the electrode pad 24 of the electronic component 2 is formed, and the wiring 4 is covered with a resin 8. Finally, the cover 6 and the substrate 1 are joined by a joining material 7.

[0069] Through the above steps, the MEMS module A1 can be manufactured. Since the electronic component 2 and the MEMS element 3 are formed on one chip (substrate 30), the stress relaxation material 9 can be made thick enough to suppress the influence of external stress on the movable part 340.

[0070] According to the present embodiment, the MEMS module A1 in which the electronic component 2 and the MEMS element 3 are provided on one chip (substrate 30) can accurately derive changes in external atmospheric pressure.

[0071] (Second Embodiment) The MEMS module A2 according to the present embodiment will be described.

[0072] FIG. 12 is a cross-sectional view showing the MEMS element 3A and the electronic component 2A in the MEMS module A2. The MEMS module A2 according to the present embodiment is different from the MEMS module A1 according to the first embodiment in that an interlayer film 350 is not provided, and the shape and formation method of the hollow portion 360A, etc. In the present embodiment, the points common to the first embodiment (for example, the substrate 1, the plurality of wirings 4, the cover 6, and the joining material 7, etc.) are incorporated in the description of the first embodiment, and the different points will be described below.

[0073] The MEMS element 3A and the electronic component 2A are formed on the substrate 30A and the substrate 30B. The hollow portion 360A of the MEMS element 3A can be formed by joining the substrate 30A having a groove portion and the substrate 30B. A plurality of wirings 12A and a plurality of electrode layers 12B of the electronic component 2A are formed inside the substrate 30B.

[0074] The substrate 30A can be made of the same material as the substrate 30 in the first embodiment. Examples of the substrate 30B include an SOI substrate in which an oxide film such as a silicon oxide layer and a semiconductor layer such as a silicon layer are laminated. The thickness of the substrate 30B is, for example, about 700 to 800 μm.

[0075] The hollow portion 360A is sealed. The hollow portion 360A may be a vacuum. Also, in the present embodiment, the hollow portion 360A is rectangular in the z-direction view, but is not limited thereto. The depth (z-direction dimension) of the hollow portion 360A is, for example, 5 to 15 μm.

[0076] The description of the movable portion 340 and the fixed portion 370 in the first embodiment can be applied to the movable portion 340A and the fixed portion 370A. Since the groove portion of the substrate 30A becomes the hollow portion 360A and the main surface (the main surface on the z1-direction side) of the movable portion 340A is formed from the substrate 30B, the movable portion 340A is not as thin as the movable portion 340 in the first embodiment and has a sufficient thickness to function as a movable portion. Therefore, it is not necessary to provide the interlayer film 350 as in the first embodiment.

[0077] Next, a method for manufacturing the MEMS module A2 will be described.

[0078] First, as shown in FIG. 13, a substrate 30A including a semiconductor layer is prepared. Examples of the semiconductor layer include a silicon layer. The thickness of the substrate 30A is, for example, about 700 to 800 μm.

[0079] Next, as shown in FIG. 14, a groove portion 38 is formed in the substrate 30A. The groove portion 38 can be formed, for example, by etching.

[0080] Next, as shown in FIG. 15, the substrate 30B is joined to the substrate 30A to form the hollow portion 360A. Also, in the present embodiment in which the movable portion 340A is simultaneously formed, the substrate 30B is an SOI substrate on which the oxide film 35 and the semiconductor layer 36 are laminated. In a later step, when removing a part of the substrate 30B, since the etching selectivity of the oxide film 35 with respect to the semiconductor layer 36 is large and only the oxide film 35 is etched, the depth of the hollow portion 360A can be fixed and good reproducibility can be obtained.

[0081] Next, as shown in FIG. 16, a part of the substrate 30B (oxide film 35 and semiconductor layer 36) is removed. The removal can be performed, for example, by etching using hydrogen fluoride or the like. A planarization process may be performed on the main surface of the remaining semiconductor layer 36 (the main surface on the z1 direction side) so as to obtain a flatter surface. Examples of the planarization process include grinding and providing an interlayer film having a flat surface.

[0082] Next, as shown in FIG. 17, in a direction (y direction) perpendicular to the thickness direction of the movable portion 340A, a plurality of wirings 12A and a plurality of electrode layers 12B are formed inside the substrate 30B in a region separated from the region where the MEMS element 3A is formed. Further, a protective film 10 covering the substrate 30B and the uppermost wiring 12A (on the z1 direction side) is formed.

[0083] Through the above steps, the electronic component 2A and the MEMS element 3A can be manufactured. Since the electronic component 2A and the MEMS element 3A are formed on one chip (substrate 30A and substrate 30B), the influence of the stress caused by the later-formed resin 8 on the movable portion 340A can be suppressed, and the process can be simplified. Further, since the electronic component 2A and the MEMS element 3A are not laminated, the height occupied by the electronic component 2A and the MEMS element 3A can be reduced, and the stress relaxation material 9 can be made thicker. Thereby, the influence of the external stress on the movable portion 340A can be suppressed.

[0084] Next, as shown in FIG. 12, the substrate 1, the electronic component 2A, and the MEMS element 3A are joined by a stress-relieving material 9. Further, a wiring 4 that electrically connects the electrode pad 11 of the substrate 1 and the electrode pad 24 of the electronic component 2 is formed, and the wiring 4 is covered with a resin 8. Finally, the cover 6 and the substrate 1 are joined by a joining material 7.

[0085] Through the above steps, the MEMS module A2 can be manufactured. Since the electronic component 2A and the MEMS element 3A are formed on one chip (substrate 30A and substrate 30B), the stress-relieving material 9 can be made thick enough to suppress the influence of external stress on the movable part 340A.

[0086] According to the present embodiment, the MEMS module A2 in which the electronic component 2A and the MEMS element 3A are provided on one chip (substrate 30A and substrate 30B) can accurately derive changes in the external atmospheric pressure.

[0087] (Third Embodiment) The MEMS module A3 according to the present embodiment will be described.

[0088] FIG. 18 is a plan view showing the MEMS element 3B and the electronic component 2B in the MEMS module A3. FIG. 19 is a cross-sectional view taken along the line V-V in FIG. 18. The difference between the MEMS module A3 according to the present embodiment and the MEMS module A1 according to the first embodiment is that in the substrate 30, there is a groove portion 13 that extends in the thickness direction from the main surface of the substrate 30 facing the z1 direction between the MEMS element 3B and the electronic component 2B. In the present embodiment, the points common to the first embodiment (for example, the substrate 1, the plurality of wirings 4, the cover 6, and the joining material 7, etc.) are incorporated by reference from the description of the first embodiment, and the differences will be described below.

[0089] Also, the MEMS element 3B and the electronic component 2B are electrically connected by a wiring 12A. The wiring 12A has a region 14 that is located on the outer edge side of the substrate 30 from the end of the groove portion 13 in the x direction.

[0090] By providing the groove portion 13, the stress applied to the MEMS element 3B and the stress applied to the electronic component 2B can be separated, and the influence on the MEMS element 3B due to the stress applied to the electronic component 2B can be suppressed.

[0091] Also, the description of the MEMS element 3 in the first embodiment can be applied to the MEMS element 3B.

[0092] The manufacturing method of the MEMS module A3 is, for example, when forming the plurality of wirings 12A and the plurality of electrode layers 12B in the first embodiment, in the x direction, the wiring 12A is formed so as to have a region 14 located on the outer edge side of the substrate 30 from the end of the groove portion 13. Then, a protective film 10 is formed as in the first embodiment, the substrate 1, the electronic component 2B, and the MEMS element 3B are joined by the stress relaxation material 9, the wiring 4 is formed, the wiring 4 is covered with the resin 8, and the cover 6 and the substrate 1 are joined by the joining material 7, whereby the MEMS module A3 can be manufactured.

[0093] According to the present embodiment, the MEMS module A3 in which the electronic component 2B and the MEMS element 3B are provided on one chip (substrate 30) can accurately derive the change in the external air pressure.

[0094] (Fourth Embodiment) The MEMS module A4 according to the present embodiment will be described.

[0095] FIG. 20 is a cross-sectional view showing the MEMS element 3C and the electronic component 2C in the MEMS module A4. The difference between the MEMS module A4 according to the present embodiment and the MEMS module A1 according to the first embodiment is that it includes a protective film 10A having an opening 10B. In the present embodiment, the points common to the first embodiment (for example, the substrate 1, the plurality of wirings 4, the cover 6, and the joining material 7, etc.) are applied to the description of the first embodiment, and the different points will be described below.

[0096] The MEMS element 3C includes a protective film 10A having an opening 10B. The opening 10B is above the movable part 340 when viewed from the thickness direction (x direction) of the movable part 340. By providing the opening 10B in the protective film 10A, the stress caused by the protective film 10A and the like applied to the MEMS element 3C can be suppressed.

[0097] Also, the description of the electronic component 2 in the first embodiment can be applied to the electronic component 2C.

[0098] For example, in the manufacturing method of the MEMS module A4, after forming the protective film 10 in the first embodiment, an opening 10B is formed above the movable part 340 when viewed from the thickness direction (x direction) of the movable part 340 by etching or the like, so that a protective film 10A having the opening 10B can be obtained. Thereafter, the substrate 1, the electronic component 2C, and the MEMS element 3C are joined by the stress relaxation material 9 as in the first embodiment, the wiring 4 is formed, the wiring 4 is covered with the resin 8, and the cover 6 and the substrate 1 are joined by the joining material 7, whereby the MEMS module A4 can be manufactured.

[0099] (Other Embodiments) As described above, although one embodiment has been described, the discussions and drawings forming a part of the disclosure are exemplary and should not be construed as limiting. Various alternative embodiments, examples, and operation techniques will be apparent to those skilled in the art from this disclosure. Thus, this embodiment includes various embodiments and the like not described herein.

Description of Reference Numerals

[0100] 1, 30, 30A, 30B Substrate 1a Mounting Surface 1b, 2b, 3b Mounting Surface 1A Base Material 1B Wiring Portion 1C Insulating Layer 2, 2A, 2B, 2C Electronic Component 2a, 3a Main Surface 3, 3A, 3B, 3C MEMS Element 4, 12A Wiring 6 Cover 7 Bonding material 8 Resin 9 Stress relaxation material 10, 10A Protective film 10B, 61 Opening 11, 24 Electrode pad 12B Electrode layer 13, 31, 38 Groove 14, 330, 335 Region 19 Back pad 35 Oxide film 36 Semiconductor layer 62 Extension 100 Mounting surface 320 Gauge resistor 340, 340A Movable part 350 Interlayer film 360, 360A Hollow part 370, 370A Fixed part A1, A2, A3, A4 MEMS module

Claims

1. A MEMS device formed on a substrate having a hollow portion with a sealed perimeter inside, having a movable portion disposed adjacent to the hollow portion inside the substrate, wherein the movable portion has a thickness such that its shape can be deformed by the pressure difference between the air pressure inside the hollow portion and the air pressure outside the substrate, and the MEMS device; an electronic component formed on the substrate and to which the output signal of the MEMS device is input; a printed circuit board; and a stress relaxation material disposed between the printed circuit board, the MEMS device, and the substrate including the electronic component, wherein the electronic component and the MEMS device are spaced apart from each other in a direction perpendicular to the thickness direction of the movable portion. A MEMS module.

2. The MEMS module according to claim 1, wherein in the substrate, there is a groove portion extending in the thickness direction of the substrate from the main surface of the substrate between the MEMS device and the electronic component.

3. Further comprising a first wiring having a region located on the outer edge side of the substrate from the end of the groove portion in a direction in which the electronic component and the MEMS device are spaced apart from each other and in a direction perpendicular to the thickness direction of the movable portion, wherein the MEMS device and the electronic component are electrically connected to the first wiring. The MEMS module according to claim 2.

4. Further comprising a protective film having an opening on the substrate, wherein the protective film covers at least a part of the electronic component, and the opening is above the movable portion when viewed from the thickness direction of the movable portion. The MEMS module according to any one of claims 1 to 3.

5. The MEMS module according to any one of claims 1 to 4, wherein the thickness of the stress relaxation material is 35 to 80 μm.

6. Further comprising a second wiring electrically connecting the printed circuit board and the electronic component, wherein on the side of the electronic component opposite to the side where the MEMS device is located, the second wiring is electrically connected to the electronic component. The MEMS module according to claim 5.

7. The MEMS module according to any one of claims 1 to 6, wherein the substrate is made of silicon.

8. A plurality of groove portions are formed in the semiconductor layer included in the substrate, Etch the semiconductor layer in a direction perpendicular to the depth direction of the groove portion from the bottom surface of the groove portion to connect the plurality of groove portions, perform a heat treatment on the semiconductor layer, and a part of the semiconductor layer melted by the heat treatment closes the groove portion to form the MEMS element having a hollow portion with a sealed periphery. Form the electronic component into which the output signal of the MEMS element is input on the substrate. The manufacturing method of the MEMS module according to claim 1, wherein the electronic component and the MEMS element are separated from each other in a direction perpendicular to the depth direction of the groove portion.

9. The plurality of groove portions are formed by deep etching. The manufacturing method of the MEMS module according to claim 8, wherein the etching is isotropic etching.

10. The heat treatment is performed at 1100 to 1200 ° C. to cause a thermal migration phenomenon in the semiconductor layer to close the groove portion to form the hollow portion. The manufacturing method of the MEMS module according to claim 8 or 9.

11. Prepare a first substrate including a semiconductor layer and a second substrate having the semiconductor layer laminated on an oxide film. Form a groove portion on the first substrate. Bond the semiconductor layer of the second substrate on the first substrate on which the groove portion is formed to form the MEMS element having a hollow portion with a sealed periphery formed in the groove portion of the first substrate. Remove the oxide film of the second substrate. Form the electronic component into which the output signal of the MEMS element is input on the second substrate. The manufacturing method of the MEMS module according to claim 1, wherein the electronic component and the MEMS element are separated from each other in a direction perpendicular to the depth direction of the groove portion.

12. The manufacturing method of the MEMS module according to claim 11, wherein the oxide film is a silicon oxide layer.

13. The manufacturing method of the MEMS module according to any one of claims 8 to 12, wherein the semiconductor layer is a silicon layer.

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