Composite sensor and method for manufacturing same

Abstract

A composite sensor (1) comprises: a first substrate (50); a second substrate (30) that faces the first substrate (50) across a gap; a first sealing frame (43) that seals a first space (48) between the first substrate (50) and the second substrate (30); and a second sealing frame (44) that seals a second space (49) between the first substrate (50) and the second substrate (30). One of the first space (48) and the second space (49) is provided with an acceleration sensor (11), and the other is provided with an angular velocity sensor (12). The degree of vacuum of the first space (48) is different from that of the second space (49). The first sealing frame (43) and the second sealing frame (44) are each made of an eutectic alloy.

Description

Composite sensor and its manufacturing method

[0001] The present invention relates to a composite sensor and a manufacturing method thereof.

[0002] In a composite sensor equipped with an acceleration sensor and an angular velocity sensor, the acceleration sensor and the angular velocity sensor require different degrees of vacuum, so they have traditionally been manufactured separately and then mounted. However, mounting multiple sensors can cause axial misalignment between the sensors, hindering high performance. For this reason, research is underway into a manufacturing method in which spaces with different degrees of vacuum are formed within the same substrate and the acceleration sensor and the angular velocity sensor are sealed therein.

[0003] For example, Patent Document 1 discloses a method for manufacturing a physical quantity sensor, which includes: a preparation step of preparing a support substrate on which a first sensor element and a second sensor element are provided; and a sealing substrate on which a first recess and a second recess are provided on the support substrate side and which has a through hole communicating with the first recess; a bonding step of bonding the sealing substrate to the support substrate so that the first sensor element is housed in the first recess and the second sensor element is housed in the second recess; and a sealing step of filling the through hole with a sealant having a melting point lower than the melting point or softening point of the support substrate and the sealing substrate to seal the first recess.

[0004] For example, Patent Document 2 discloses a method for manufacturing a composite sensor in which a movable body of an acceleration sensor and a vibrating body of an angular velocity sensor are placed on the same sensor wafer, separated by a wall, a cap wafer is formed with gaps corresponding to each sensor, through holes and bumps are formed in the sensor sealing portion, the acceleration sensor is sealed to atmospheric pressure by anodic bonding in a first sealing process, the internal pressure of the angular velocity sensor is adjusted via the ventilation path and through holes formed by the bumps, a load is applied in a high-temperature atmosphere to deform the bumps in a second sealing process, the sensor wafer and cap wafer are brought into contact in a vacuum atmosphere and anodically bonded, and the angular velocity sensor is vacuum-sealed.

[0005] JP 2016-33464 A International Publication No. 2013 / 080238

[0006] However, the manufacturing method of a physical quantity sensor described in Patent Document 1 requires steps such as forming a through hole, arranging a sealing material, and melting the sealing material, which increases the number of manufacturing steps, and may cause problems such as increased manufacturing costs, longer lead times, and an increased rate of defective products. Furthermore, not only the joint between the support substrate and the sealing substrate but also the through hole sealed with the sealing material may become a leak path, which may increase the rate of defective sealing and reduce reliability.

[0007] Furthermore, the manufacturing method of the composite sensor described in Patent Document 2 requires the creation of through-holes in the sensor wafer and the provision of bumps on the bonding surface of the cap wafer, which must be mirror-finished for anodic bonding, making the manufacturing process complicated. Furthermore, the area around the deformed bumps may become a leak path, increasing the incidence of defective sealing and reducing reliability.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a highly reliable composite sensor that can be manufactured by a simple process, and a method for manufacturing the same.

[0009] A composite sensor according to one aspect of the present invention comprises a first substrate, a second substrate facing the first substrate with a gap therebetween, a first sealing frame sealing a first space between the first substrate and the second substrate, and a second sealing frame sealing a second space between the first substrate and the second substrate, wherein an acceleration sensor is provided in one of the first space or the second space and an angular velocity sensor is provided in the other, the degree of vacuum in the first space is different from the degree of vacuum in the second space, and both the first sealing frame and the second sealing frame are made of a eutectic alloy.

[0010] A method for manufacturing a composite sensor according to another aspect of the present invention includes preparing a first substrate and a second substrate facing the first substrate with a gap therebetween, sealing a first space between the first substrate and the second substrate with a first sealing frame, and sealing a second space between the first substrate and the second substrate with a second sealing frame, wherein an acceleration sensor is provided in one of the first space or the second space and an angular velocity sensor is provided in the other, the degree of vacuum in the first space is different from the degree of vacuum in the second space, and both the first sealing frame and the second sealing frame are made of a eutectic alloy.

[0011] According to the present invention, it is possible to provide a highly reliable composite sensor with a simple manufacturing process, and a manufacturing method thereof.

[0012] 1. A cross-sectional view of the combined sensor according to the first embodiment. 2. A plan view of the combined sensor according to the first embodiment. 3. A flowchart showing a manufacturing method for the combined sensor according to the first embodiment. 4. A cross-sectional view showing the manufacturing process of the combined sensor according to the first embodiment. 5. A cross-sectional view showing the manufacturing process of the combined sensor according to the first embodiment. 6. A cross-sectional view of the combined sensor according to the second embodiment. 7. A flowchart showing a manufacturing method for the combined sensor according to the second embodiment. 8. A cross-sectional view showing the manufacturing process of the combined sensor according to the second embodiment. 9. A cross-sectional view showing the manufacturing process of the combined sensor according to the second embodiment. 10. A cross-sectional view of the combined sensor according to the third embodiment. 11. A cross-sectional view showing the manufacturing process of the combined sensor according to the third embodiment. 12. A cross-sectional view showing the manufacturing process of the combined sensor according to the third embodiment. 13. A cross-sectional view showing the manufacturing process of the combined sensor according to the third embodiment. 14. A cross-sectional view showing the manufacturing process of the combined sensor according to the third embodiment. 15. A cross-sectional view of the combined sensor according to the fourth embodiment. 16. A cross-sectional view showing the manufacturing process of the combined sensor according to the fourth embodiment. 17. A plan view of the combined sensor according to the fifth embodiment. 18. A plan view of the combined sensor according to the sixth embodiment.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings of the present embodiment are merely examples, and the dimensions and shapes of each part are schematic, so the technical scope of the present invention should not be interpreted as being limited to the embodiment.

[0014] First Embodiment First, the configuration of a composite sensor 1 according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a cross-sectional view of the composite sensor according to the first embodiment. Fig. 2 is a plan view of the composite sensor according to the first embodiment.

[0015] The components of the composite sensor 1 are described below. For the sake of clarity and understanding of the relative positions of the components, each drawing may be accompanied by a Cartesian coordinate system consisting of an X-axis, a Y-axis, and a Z-axis. The directions parallel to the X-axis, the Y-axis, and the Z-axis are referred to as the X-axis, the Y-axis, and the Z-axis, respectively. The plane defined by the X-axis and the Y-axis is referred to as the XY plane. For the sake of convenience, the positive Z-axis direction (the direction of the arrow) will be referred to as the top or upper side, and the negative Z-axis direction (the direction opposite to the arrow) will be referred to as the bottom or lower side, but the orientation of the composite sensor 1 is not limited to this.

[0016] The composite sensor 1 includes a device layer 10, a bottom lid 20, a top lid 30, and a bonding layer 40. The bottom lid 20, the device layer 10, the bonding layer 40, and the top lid 30 are stacked in this order in the Z-axis direction. Hereinafter, the Z-axis direction in which the bottom lid 20, the device layer 10, the bonding layer 40, and the top lid 30 are stacked will be referred to as the "thickness direction." The device layer 10 and the bottom lid 20 are bonded together to form a MEMS substrate 50. The top lid 30 is bonded to the device layer 10 of the MEMS substrate 50 by the bonding layer 40. In other words, the top lid 30 is bonded to the bottom lid 20 via the device layer 10 and the bonding layer 40. The bottom lid 20 and the top lid 30 face each other in the thickness direction, with the device layer 10 and the bonding layer 40 sandwiched between them. The bottom lid 20, the bonding layer 40, and the top lid 30 form a package structure that forms an internal space for the movable portion of the device layer 10 to move. The MEMS substrate 50 corresponds to an example of a first substrate, and the top cover 30 corresponds to an example of a second substrate.

[0017] When the device layer 10 and the lower lid 20 are considered as a MEMS substrate 50, for example, the silicon substrate P10 of the lower lid 20, which will be described later, corresponds to the support substrate (handle layer) of the SOI substrate, the silicon oxide film P11 of the lower lid 20, which will be described later, corresponds to the BOX layer of the SOI substrate, and the silicon substrate F10 of the device layer 10, which will be described later, corresponds to the active layer (device layer) of the SOI substrate.

[0018] The device layer 10 is provided by a silicon substrate F10. The silicon substrate F10 is formed, for example, of single crystal silicon. The silicon substrate F10 is formed, for example, of a p-type silicon (Si) semiconductor. The silicon substrate F10 may contain boron (B) or the like as a p-type dopant. The resistance value of the silicon (Si) used in the silicon substrate F10 is, for example, about 10 mΩ·cm. Note that the material of the device layer 10 is not limited to a silicon semiconductor, and is not particularly limited as long as it can be used to form an acceleration sensor and an angular velocity sensor.

[0019] The device layer 10 includes an acceleration sensor 11, an angular velocity sensor 12, and a convex portion 13. The acceleration sensor 11, the angular velocity sensor 12, and the convex portion 13 are formed by performing patterning by removal processing on the silicon substrate F10. The removal processing for forming the convex portion 13 is performed using, for example, HF and HNO ３ The removal process for forming the acceleration sensor 11 and the angular velocity sensor 12 is performed by dry etching called DRIE (Deep Reactive Ion Etching), which is a type of sputter etching in which ions accelerated by an electric field are irradiated. Note that the removal process for forming the protrusions 13 and the removal process for forming the acceleration sensor 11 and the angular velocity sensor 12 are not limited to the above, and may be performed by other methods such as crystal anisotropic wet etching using an alkaline etching solution, isotropic dry etching using a reactive gas or plasma, vertical anisotropic dry etching using reactive ions, and laser etching.

[0020] The device layer 10 forms movable spaces 28, 29 between itself and the lower lid 20, and forms movable spaces 48, 49 between itself and the upper lid 30. The movable spaces 28 and 29 are partitioned, and the movable spaces 48 and 49 are partitioned. The movable spaces 28 and 48 are connected, and the movable spaces 29 and 49 are connected. The movable spaces 28, 48 are movable spaces for the acceleration sensor 11, and the movable spaces 29, 49 are movable spaces for the angular velocity sensor 12. The movable spaces 28, 48 correspond to an example of a first space, and the movable spaces 29, 49 correspond to an example of a second space.

[0021] The acceleration sensor 11 detects acceleration in the X-axis, Y-axis, or Z-axis direction based on changes in the capacitance of a movable portion formed on the silicon substrate F10. It is desirable for the acceleration sensor 11 to be strongly subjected to the damping effect of the sealed gas in order to suppress free vibration of the movable portion. Therefore, the movable spaces 28, 48 in which the acceleration sensor 11 resides are sealed at a low vacuum. The air pressure in the movable spaces 28, 48 is preferably between 0.1 and 10 atmospheres, more preferably between 0.5 and 5 atmospheres, and is set to, for example, about 1 atmosphere. By setting the air pressure in the movable spaces 28, 48 to 0.1 atmospheres or higher, preferably 0.5 atmospheres or higher, the damping effect on the acceleration sensor 11 can be sufficiently obtained, improving acceleration detection sensitivity. Furthermore, by setting the air pressure to 10 atmospheres or lower, preferably 5 atmospheres or lower, the damping effect on the acceleration sensor 11 can be prevented from becoming excessive, thereby preventing a decrease in acceleration detection sensitivity.

[0022] The angular velocity sensor 12 detects angular velocity around the X-axis, Y-axis, or Z-axis direction as the rotation axis based on changes in the capacitance of a movable part formed on the silicon substrate F10. To increase the displacement and improve sensitivity, the angular velocity sensor 12 is desirably less susceptible to the damping effect of the sealed gas. Therefore, the movable spaces 29, 49 in which the angular velocity sensor 12 resides are sealed at a higher vacuum than the movable spaces 28, 48. The air pressure in the movable spaces 29, 49 is desirably between 1 Pa and 100 Pa, and more desirably between 5 Pa and 50 Pa, for example, set to approximately 10 Pa. By setting the air pressure in the movable spaces 29, 49 to 1 Pa or higher, preferably 5 Pa or higher, increases in manufacturing costs and time can be suppressed. By setting the air pressure in the movable spaces 29, 49 to 100 Pa or lower, preferably 50 Pa or lower, the damping effect on the angular velocity sensor 12 can be sufficiently suppressed, improving angular velocity detection sensitivity.

[0023] Both the movable spaces 28 and 48 corresponding to the first spaces and the movable spaces 29 and 49 corresponding to the second spaces are filled with an inert gas, such as nitrogen, argon, helium, or neon.

[0024] The protrusions 13 protrude toward the top cover 30. The protrusions 13 come into contact with contact portions 46, which will be described later, and electrically connect the MEMS substrate 50 and the top cover 30.

[0025] The lower lid 20 is made up of a silicon substrate P10 and a silicon oxide film P11. The silicon oxide film P11 is provided on the upper surface of the lower lid 20 that is bonded to the device layer 10. The silicon substrate P10 of the lower lid 20 is bonded to the silicon substrate F10 of the device layer 10 via the silicon oxide film P11.

[0026] The lower lid 20 has a bottom plate 22, side walls 23, a support portion 24, and an inner wall 25. Movable spaces 28, 29 surrounded by the bottom plate 22 and the side walls 23 are formed in the lower lid 20 on the side facing the acceleration sensor 11 and the angular velocity sensor 12 of the device layer 10. The inner wall 25 partitions the movable spaces 28 and 29. The movable space 28 is a rectangular parallelepiped opening that opens toward the acceleration sensor 11. The movable space 29 is a rectangular parallelepiped opening that opens toward the angular velocity sensor 12.

[0027] The bottom plate 22 is provided at a distance in the thickness direction from the acceleration sensor 11 and the angular velocity sensor 12. The bottom plate 22 is a plate-shaped portion having a main surface extending along the XY plane. The bottom plate 22 is provided by a silicon substrate P10.

[0028] The sidewall 23 extends from the peripheral edge of the bottom plate 22 toward the top lid 30. The sidewall 23 is a frame-shaped portion that surrounds the acceleration sensor 11 and the angular velocity sensor 12 in a plan view. The base end of the sidewall 23, which connects to the bottom plate 22, is provided by the silicon substrate P10. A silicon oxide film P11 is provided at the tip of the sidewall 23, and the sidewall 23 is joined to the silicon substrate F10 of the device layer 10 via the silicon oxide film P11.

[0029] The support portion 24 extends from the bottom plate 22 toward the device layer 10. The base end of the support portion 24, which connects to the bottom plate 22, is provided by the silicon substrate P10. A silicon oxide film P11 is provided at the tip end of the support portion 24, and the support portion 24 is connected to the silicon substrate F10 of the acceleration sensor 11 via the silicon oxide film P11.

[0030] The inner wall 25 extends from the center of the bottom plate 22 toward the top lid 30. In plan view, the inner wall 25 is located between the acceleration sensor 11 and the angular velocity sensor 12. A base end of the inner wall 25 that connects to the bottom plate 22 is provided by a silicon substrate P10. A silicon oxide film P11 is provided at the tip of the inner wall 25, and the inner wall 25 is joined to the silicon substrate F10 of the device layer 10 via the silicon oxide film P11.

[0031] The top cover 30 is provided in a flat plate shape. The top cover 30 is formed, for example, by a silicon substrate Q10 and a glass substrate Q11. The silicon substrate Q10 is formed, for example, by a p-type silicon (Si) semiconductor. The resistance value of the silicon (Si) used in the silicon substrate Q10 is, for example, about 10 mΩ·cm. The glass substrate Q11 is formed, for example, by a silicon oxide (for example, SiO ２ The glass substrate Q11 is formed of silicate glass primarily composed of ammonium hydroxide. Here, the term "major component" refers to a component that accounts for 50% by mass or more of all components constituting the glass. As an example, the glass substrate Q11 is formed of alkali-free glass. When the glass substrate Q11 of the top cover 30 and the silicon substrate F10 of the device layer 10 are anodically bonded, the glass substrate Q11 must be alkali glass. However, in the present embodiment, in which bonding is performed using a eutectic alloy H10, which will be described later, the glass substrate Q11 may be formed of alkali-free glass. When the glass substrate Q11 is formed of alkali-free glass, no change in characteristics due to alkali migration occurs, thereby improving the reliability of the composite sensor 1.

[0032] The glass substrate Q11 is mainly provided on the MEMS substrate 50 side of the silicon substrate Q10. The silicon substrate Q10 is provided in multiple regions spaced apart in the XY plane. The glass substrate Q11 extends between the multiple silicon substrates Q10 provided in the regions spaced apart in the XY plane, electrically insulating the multiple silicon substrates Q10 from each other. In the region overlapping with the contact portion 46 (described later), the silicon substrate Q10 penetrates the glass substrate Q11 in the Z-axis direction.

[0033] The material of the top cover 30 is not limited to the silicon substrate Q10 and the glass substrate Q11. The top cover 30 may have a silicon oxide film instead of the glass substrate Q11, or may further have a silicon oxide film in addition to the silicon substrate Q10 and the glass substrate Q11. The top cover 30 may also be formed using a compound semiconductor substrate, a glass substrate, a ceramic substrate, a resin substrate, or a substrate combining these. Furthermore, a through electrode penetrating the glass substrate Q11 may be provided in a region overlapping with the contact portion 46 (described later). Such a through electrode is formed, for example, by filling a through hole with polycrystalline silicon (Poly-Si), copper (Cu), gold (Au), or the like.

[0034] The bonding layer 40 has sealing frames 43 and 44 , a spacer portion 45 and a contact portion 46 .

[0035] As shown in Fig. 1, the sealing frames 43 and 44 join the MEMS substrate 50 and the upper cover 30. The sealing frame 43 seals the movable space 48, and the sealing frame 44 seals the movable space 49. As shown in Fig. 2, the sealing frame 43 is provided in the shape of a continuous frame in the circumferential direction surrounding the movable space 48, and the sealing frame 44 is provided as part of a frame in the circumferential direction surrounding the movable space 49. The sealing frame 44 is connected to the sealing frame 43, and the movable space 49 is surrounded by the sealing frame 43 and the sealing frame 44. The sealing frame 43 corresponds to an example of a first sealing frame, and the sealing frame 44 corresponds to an example of a second sealing frame.

[0036] As shown in FIG. 1 , the sealing frame 43 has a silicon oxide film G10 and a eutectic alloy H11 stacked in the thickness direction, and the sealing frame 44 has a silicon oxide film G10 and a eutectic alloy H12 stacked in the thickness direction. The eutectic alloy H11 is provided between the silicon oxide film G10 and the glass substrate Q11, and the eutectic alloy H12 is provided between the silicon oxide film G10 and the glass substrate Q11. The silicon oxide film G10 is provided between the silicon substrate F10 and the eutectic alloy H11, and between the silicon substrate F10 and the eutectic alloy H12. The silicon oxide film G10 is provided on the surface of the silicon substrate F10 facing the top lid 30. The eutectic alloys H11 and H12 are provided on the surface of the glass substrate Q11 facing the MEMS substrate 50. The silicon oxide film G10 prevents components of the silicon substrate F10 from mixing with the eutectic alloys H11 and H12.

[0037] The eutectic alloys H11 and H12 are, for example, Al-Ge-Ti eutectic alloys containing aluminum (Al), germanium (Ge), and titanium (Ti). The composition of the eutectic alloy H11 is different from the composition of the eutectic alloy H12. For example, the weight ratio of aluminum to germanium present in the eutectic alloy H11 is Al:Ge = 1:1, and the weight ratio of aluminum to germanium present in the eutectic alloy H12 is Al:Ge = 4:6.

[0038] The eutectic alloys H11 and H12 are not limited to Al-Ge-Ti eutectic alloys, and may be, for example, Al-Ge eutectic alloys, Au-Sn eutectic alloys, Al-Si eutectic alloys, etc. The weight ratio of aluminum to germanium present in the eutectic alloy H11 may be approximately the same as the weight ratio of aluminum to germanium present in the eutectic alloy H12.

[0039] The spacer portion 45 has an aluminum layer H31, a titanium layer H32, and an aluminum layer H33. The aluminum layer H31, titanium layer H32, and aluminum layer H33 are stacked in this order in the Z-axis direction. The aluminum layer H31 is provided on the MEMS substrate 50 side of the glass substrate Q11 of the top cover 30. The titanium layer H32 is provided on the MEMS substrate 50 side of the aluminum layer H31. The aluminum layer H33 is provided on the MEMS substrate 50 side of the titanium layer H32. The aluminum layers H31 and H33 are made of aluminum (Al), and the titanium layer H32 is made of titanium (Ti).

[0040] The spacer portion 45 controls the gap between the MEMS substrate 50 and the top lid 30. The spacer portion 45 extends from the top lid 30 in the negative Z-axis direction and abuts against the silicon substrate F10 of the device layer 10. At a temperature sufficiently lower than the melting point of aluminum, the spacer portion 45 maintains the gap between the MEMS substrate 50 and the top lid 30 against pressure in a direction narrowing the gap between the MEMS substrate 50 and the top lid 30. At a temperature close to the melting point of aluminum, the spacer portion 45 deforms in response to pressure in a direction narrowing the gap between the MEMS substrate 50 and the top lid 30, and the gap narrows in response to the pressure.

[0041] The contact portion 46 has an aluminum layer H31. The contact portion 46 extends from the top cover 30 toward the negative side of the Z axis and abuts against the convex portion 13 of the silicon substrate F10 of the device layer 10. The contact portion 46 electrically connects the silicon substrate Q10 exposed on the MEMS substrate 50 side of the top cover 30 to the convex portion 13 of the device layer 10. This electrically connects an external electrode (not shown) of the composite sensor 1 to the acceleration sensor 11 or the angular velocity sensor 12.

[0042] Next, a method for manufacturing the composite sensor 1 according to the first embodiment will be described with reference to Fig. 3 to Fig. 6. Fig. 3 is a flowchart showing the method for manufacturing the composite sensor according to the first embodiment. Fig. 4 to Fig. 6 are cross-sectional views showing the manufacturing process of the composite sensor according to the first embodiment.

[0043] In manufacturing the composite sensor 1, first, a first substrate (MEMS substrate 50) and a second substrate (upper cover 30) are prepared (S10).

[0044] In the process of preparing the MEMS substrate 50, first, a silicon substrate P10 is prepared and one side thereof is mirror-polished. A silicon oxide film P11 is formed on the mirror surface side of the silicon substrate P10. The silicon oxide film P11 and the upper surface side of the silicon substrate P10 are partially removed by dry etching or the like to form movable spaces 28 and 29.

[0045] Next, the silicon substrate F10 is bonded to the lower lid 20. First, the silicon substrate F10 is prepared and one side is mirror-polished. The mirror surface of the silicon substrate F10 is brought into contact with the silicon oxide film P11 and heat-treated to directly bond the silicon substrate F10 and the silicon oxide film P11. Next, a protrusion 13 is formed on the silicon substrate F10 by wet etching. Note that the protrusion 13 may be formed prior to the direct bonding of the silicon substrate F10 and the silicon oxide film P11.

[0046] Next, the silicon substrate F10 is removed to form the device layer 10. Specifically, a photoresist is patterned on the upper surface of the silicon substrate F10, and the silicon substrate F10 is removed by dry etching. As a result, an acceleration sensor 11 and an angular velocity sensor 12 are formed, as shown in FIG.

[0047] Next, as shown in FIG. 4 , metal frames 53 and 54 are provided. The metal frame 53 corresponds to an example of a first metal frame, and the metal frame 54 corresponds to an example of a second metal frame. The metal frames 53 and 54 include a titanium layer H51 and a germanium layer H52. Providing the metal frames 53 and 54 includes providing a silicon oxide film G10 in the area of ​​the surface of the silicon substrate F10 where the sealing frames 43 and 44 will be provided, providing a titanium layer H51 on the silicon oxide film G10, and providing a germanium layer H52 on the titanium layer H51. The titanium layer H51 of the metal frames 53 and 54 is provided in the same process, and the germanium layer H52 of the metal frames 53 and 54 is provided in the same process. The thickness of the metal frame 53 along the Z-axis direction is equal to the thickness of the metal frame 54 along the Z-axis direction.

[0048] In the process of preparing the top cover 30, first, a composite substrate is prepared by combining a silicon substrate Q10 and a glass substrate Q11, and both surfaces of the composite substrate are polished.

[0049] Next, as shown in FIG. 4 , metal frames 33 and 34, a spacer portion 45, and a contact portion 46 are provided. The metal frame 33 corresponds to an example of a third metal frame, and the metal frame 34 corresponds to an example of a fourth metal frame. The metal frame 33 and the spacer portion 45 include an aluminum layer H31, a titanium layer H32, and an aluminum layer H33. The metal frame 34 includes a titanium layer H32 and an aluminum layer H33. The contact portion 46 includes an aluminum layer H31. The thickness of the metal frame 33 along the Z-axis direction is equal to the thickness of the spacer portion 45 along the Z-axis direction. The thickness of the metal frame 34 along the Z-axis direction is smaller than the thickness of the metal frame 33 along the Z-axis direction. The thickness of the contact portion 46 along the Z-axis direction is smaller than the thickness of the metal frame 34 along the Z-axis direction.

[0050] Providing the metal frame 33 and the spacer portion 45 includes providing an aluminum layer H31 on the glass substrate Q11 in the region where the sealing frame 43 and the spacer portion 45 are to be provided, providing a titanium layer H32 on the aluminum layer H31, and providing an aluminum layer H33 on the titanium layer H32. Providing the metal frame 34 includes providing a titanium layer H32 on the glass substrate Q11 in the region where the sealing frame 44 is to be provided, and providing an aluminum layer H33 on the titanium layer H32. Providing the contact portion 46 includes providing an aluminum layer H31 on the silicon substrate Q10 in the region where the contact portion 46 is to be provided. The metal frame 33, the spacer portion 45, and the aluminum layer H31 of the contact portion 46 are provided in the same process. The titanium layer H32 of the metal frames 33, 34, and the spacer portion 45 are provided in the same process. The aluminum layer H33 of the metal frames 33, 34, and the spacer portion 45 are provided in the same process.

[0051] 4 , the MEMS substrate 50 and the top lid 30 are disposed facing each other in the chamber CH. Between the opposed MEMS substrate 50 and top lid 30, the gap between the metal frames 53 and 33 is smaller than the gap between the metal frames 54 and 34. The gap between the spacer portion 45 and the silicon substrate F10 is equal in size to the gap between the contact portion 46 and the protrusion 13, is larger than the gap between the metal frames 53 and 33, and is smaller than the gap between the metal frames 54 and 34. In other words, as the MEMS substrate 50 and the top lid 30 approach each other, first the metal frames 53 and 33 come into contact, then the spacer portion 45 and the silicon substrate F10 come into contact, then the contact portion 46 and the protrusion 13 come into contact, and finally the metal frames 54 and 34 come into contact.

[0052] Note that, as long as the metal frame 53 and the metal frame 33 come into contact first, the configuration is not limited to one in which the thickness of the metal frame 53 is equal to the thickness of the metal frame 54 and the thickness of the metal frame 33 is greater than the thickness of the metal frame 34. For example, the thickness of the metal frame 53 may be greater than the thickness of the metal frame 54 and the thickness of the metal frame 33 may be equal to the thickness of the metal frame 34. Furthermore, the thickness of the metal frame 53 may be greater than the thickness of the metal frame 54 and the thickness of the metal frame 33 may be greater than the thickness of the metal frame 34.

[0053] The air in the chamber CH is evacuated and the chamber CH is filled with an inert gas GS. The degree of vacuum in the chamber CH is preferably about 0.1 atmospheres or more and 10 atmospheres or less, more preferably about 0.5 atmospheres or more and 5 atmospheres or less, and is set to, for example, about 1 atmosphere.

[0054] In this embodiment, the spacer portion 45 is provided on the top cover 30, but the configuration of the spacer portion is not limited to this. The spacer portion may be provided on the MEMS substrate, or on both the MEMS substrate and the top cover. Similarly, the contact portion may be provided on the MEMS substrate, or on both the MEMS substrate and the top cover.

[0055] Next, the first spaces (movable spaces 28, 48) are sealed (S20).

[0056] Sealing the movable spaces 28, 48 includes causing a eutectic reaction between the metal frame 53 and the metal frame 33. Specifically, the MEMS substrate 50 and the top cover 30 are heated to a first temperature, and then the MEMS substrate 50 and the top cover 30 are sandwiched together at a first pressure so that they approach each other. The first temperature is higher than the eutectic temperature of the Al-Ge-Ti eutectic alloy and lower than the melting point of aluminum. The first pressure is also lower than the pressure that deforms aluminum at the first temperature. Therefore, when the MEMS substrate 50 and the top cover 30 approach each other, the metal frame 53 and the metal frame 33 first come into contact, causing a eutectic reaction. By forming the eutectic alloy H11, the movable spaces 28, 49 are sealed at the vacuum level within the chamber CH.

[0057] As the eutectic reaction progresses, the metal frames 53 and 33 change into a molten eutectic alloy H11, and the MEMS substrate 50 and the top cover 30 move closer to each other. At this time, the spacer portions 45 come into contact with the MEMS substrate 50 and function as supports that maintain the distance between the MEMS substrate 50 and the top cover 30. When the spacer portions 45 are in contact with the MEMS substrate 50, a gap is formed between the metal frames 54 and 34.

[0058] Next, the degree of vacuum in the chamber CH is increased (S30).

[0059] Specifically, the degree of vacuum in the chamber CH is changed with the spacer portion 45 abutting against the MEMS substrate 50 to form a gap between the metal frame 54 and the metal frame 34. By evacuating the chamber CH, the inert gas GS in the chamber CH is removed, and the degree of vacuum increases. At this time, the degree of vacuum in the chamber CH is preferably about 1 Pa or more and 100 Pa or less, more preferably 5 Pa or more and 50 Pa or less, and is set to about 10 Pa, for example.

[0060] Next, the gap between the second metal frame (metal frame 34) and the fourth metal frame (metal frame 54) is closed (S40).

[0061] Specifically, while maintaining the first temperature, the pressure sandwiching the MEMS substrate 50 and the top cover 30 is changed from the first pressure to a second pressure. The second pressure is greater than the first pressure and is a pressure at which aluminum deforms at the first temperature. As a result, the spacer portion 45 is crushed in the Z-axis direction, the MEMS substrate 50 and the top cover 30 are brought closer to each other, and the metal frames 54 and 34 are brought into contact with each other. At this time, since the MEMS substrate 50 and the top cover 30 are heated to the first temperature, the eutectic alloy H11 is melted. Therefore, as the MEMS substrate 50 and the top cover 30 are brought closer to each other, the thickness of the eutectic alloy H11 along the Z-axis direction decreases and the eutectic alloy H11 is spread along the XY plane.

[0062] Next, the second spaces (movable spaces 29, 49) are sealed (S50).

[0063] Sealing the movable spaces 29, 49 includes causing a eutectic reaction between the metal frames 54 and 34. As shown in Fig. 6, the metal frames 54 and 34, which are heated to a first temperature higher than the eutectic temperature of the Al-Ge-Ti eutectic alloy, come into contact with each other, causing the eutectic reaction between the metal frames 54 and 34 to proceed. The formation of the eutectic alloy H12 seals the movable spaces 29, 49 at the vacuum level within the chamber CH.

[0064] Finally, the composite sensor 1 is taken out of the chamber CH.

[0065] As described above, in one embodiment, the composite sensor 1 comprises a MEMS substrate 50, an upper cover 30 facing the MEMS substrate 50 with a gap therebetween, a sealing frame 43 that seals the movable spaces 28, 48, and a sealing frame 44 that seals the movable spaces 29, 49, an acceleration sensor 11 is provided in the movable spaces 28, 48, an angular velocity sensor 12 is provided in the movable spaces 29, 49, the degree of vacuum in the movable spaces 28, 48 is lower than the degree of vacuum in the movable spaces 29, 49, and the sealing frames 43, 44 are both made of a eutectic alloy.

[0066] By providing the acceleration sensor 11 and the angular velocity sensor 12 on a single MEMS substrate 50, axial misalignment between the sensors can be suppressed, improving the performance of the combined sensor 1. Furthermore, the two movable spaces are sealed by the MEMS substrate 50, the top cover 30, and the sealing frames 43 and 44. The MEMS substrate 50, the top cover 30, and the sealing frames 43 and 44 do not have through-holes or bumps for adjusting the vacuum level of the two movable spaces. This simplifies the manufacturing process. Furthermore, since there are fewer potential leak paths, reliability can be improved. Furthermore, because the MEMS substrate 50 and the top cover 30 are bonded together using a eutectic alloy, the bonding surfaces of the substrates may be made of alkali-free glass. Because alkali-free glass does not experience changes in properties due to alkali migration, it can provide improved reliability compared to alkali glass.

[0067] The angular velocity sensor 12 may be provided in the movable spaces 28, 48, and the acceleration sensor 11 may be provided in the movable spaces 29, 49. In this case, the degree of vacuum in the movable spaces 28, 48 is higher than the degree of vacuum in the movable spaces 29, 49.

[0068] In one aspect of the above, a spacer 45 is further provided between the MEMS substrate 50 and the upper cover 30 , and the spacer 45 has a metal layer made of a metal that constitutes the eutectic alloy of the sealing frames 43 and 44 .

[0069] With this, the spacer portions 45 function as supports that maintain the gap between the MEMS substrate 50 and the top cover 30, thereby preventing the gap between the MEMS substrate 50 and the top cover 30 from changing at undesired times during the manufacturing process. Therefore, the degree of vacuum in the movable spaces 28, 48 and the degree of vacuum in the movable spaces 29, 49 can be appropriately set, thereby improving reliability. Furthermore, since the spacer portions 45 can be provided during the process of providing the sealing frames 43, 44, the spacer portions 45 can be provided without increasing the number of manufacturing steps.

[0070] In another aspect, the manufacturing method of the composite sensor 1 includes preparing a MEMS substrate 50 and an upper cover 30, sealing the movable spaces 28, 48 with a sealing frame 43, and sealing the movable spaces 29, 49 with a sealing frame 44, wherein an acceleration sensor 11 is provided in the movable spaces 28, 48, and an angular velocity sensor 12 is provided in the movable spaces 29, 49, the degree of vacuum in the movable spaces 28, 48 is lower than the degree of vacuum in the movable spaces 29, 49, and the sealing frames 43, 44 are both made of a eutectic alloy.

[0071] This arrangement, by providing the acceleration sensor 11 and the angular velocity sensor 12 on a single MEMS substrate 50, reduces axial misalignment between the sensors, thereby improving the performance of the combined sensor 1. Furthermore, the two movable spaces are sealed by the MEMS substrate 50, the top cover 30, and the sealing frames 43 and 44. The manufacturing method for the combined sensor 1 does not include the step of providing through-holes or bumps in the MEMS substrate 50, the top cover 30, and the sealing frames 43 and 44 to adjust the vacuum level of the two movable spaces. This simplifies the manufacturing process. Furthermore, the reduced number of potential leak paths improves reliability. Furthermore, since the MEMS substrate 50 and the top cover 30 are bonded together using a eutectic alloy, the bonding surfaces of the substrates may be made of alkali-free glass. Because alkali-free glass does not experience changes in properties due to alkali migration, it offers improved reliability compared to alkali glass.

[0072] In one aspect of the above, preparing the MEMS substrate 50 includes providing metal frames 53, 54 on a side facing the top cover 30, preparing the top cover 30 includes providing metal frames 33, 34 on a side facing the MEMS substrate 50, sealing the movable spaces 28, 48 with the sealing frame 43 includes causing a eutectic reaction between the metal frame 53 and the metal frame 33, and sealing the movable spaces 29, 49 with the sealing frame 44 includes causing a eutectic reaction between the metal frame 54 and the metal frame 34. Preparing the MEMS substrate 50 includes providing a spacer portion 45 on a side facing the top cover 30, and further includes reducing the degree of vacuum in the chamber CH in a state where the spacer portion 45 abuts against the MEMS substrate 50 to form a gap between the metal frame 54 and the metal frame 34 after sealing the movable spaces 28, 48 with the sealing frame 43 and before sealing the movable spaces 29, 49 with the sealing frame 44. Here, the spacer portion 45 has the same layer structure as the metal frame 33.

[0073] With this, the spacer portions 45 function as supports that maintain the gap between the MEMS substrate 50 and the top cover 30, thereby preventing the gap between the MEMS substrate 50 and the top cover 30 from changing at undesired times during the manufacturing process. Therefore, the degree of vacuum in the movable spaces 28, 48 and the degree of vacuum in the movable spaces 29, 49 can be appropriately set, thereby improving reliability. Furthermore, since the spacer portions 45 can be provided during the process of providing the metal frame 33, the spacer portions 45 can be provided without increasing the number of steps in the manufacturing process.

[0074] Other embodiments will be described below. Note that components that are the same as or similar to those in the first embodiment are denoted by the same or similar reference numerals, and descriptions thereof will be omitted as appropriate. Furthermore, similar effects resulting from similar components will not be mentioned one after another.

[0075] Second Embodiment Next, the structure and manufacturing method of a composite sensor 2 according to a second embodiment will be described with reference to Fig. 7 to Fig. 11. Fig. 7 is a cross-sectional view of the composite sensor according to the second embodiment. Fig. 8 is a flowchart showing a manufacturing method of the composite sensor according to the second embodiment. Figs. 9 to 11 are cross-sectional views showing the manufacturing process of the composite sensor according to the second embodiment.

[0076] As shown in Fig. 7, the composite sensor 2 differs from the composite sensor 1 in that it does not include a spacer portion 45. As shown in Fig. 8, the manufacturing method of the composite sensor 2 includes a step S21 of provisionally sealing the first space instead of the step S20 of sealing the first space, and a step S51 of sealing the first space and the second space instead of the step S50 of sealing the second space.

[0077] As shown in FIG. 9, in step S10 of preparing the first substrate (MEMS substrate 50) and the second substrate (top cover 30), the top cover 30 does not have a spacer portion 45.

[0078] As shown in FIG. 10 , in step S21 of provisionally sealing the first space (movable spaces 28, 48), the MEMS substrate 50 and the top cover 30 are heated to a second temperature, and then the MEMS substrate 50 and the top cover 30 are sandwiched together in a direction approaching each other under a second pressure. The second temperature is higher than the eutectic temperature of the Al-Ge-Ti eutectic alloy and lower than the melting point of aluminum. The second pressure is a pressure at which the metal frames 53 and 33 are hermetically abutted against each other at the second temperature. The second pressure causes one of the metal frames 53 and 33 to sink into the other, and the metal frames 53 and 33 function as a metal gasket. The state in which the metal frames 53 and 33 are sealed without undergoing a eutectic reaction and are in abutting contact is referred to as "provisional sealing." At this time, the metal frames 33 and 53 also function as spacers that form a gap between the metal frames 54 and 34, and in this state, step S30 is carried out to reduce the degree of vacuum in the chamber CH.

[0079] 11 , in step S51 for sealing the first space (movable spaces 28, 48) and the second space (movable spaces 29, 49), the MEMS substrate 50 and the top cover 30 are heated to a first temperature. The metal frames 53 and 33, which are already in contact with each other, undergo a eutectic reaction and melt to form a eutectic alloy H11, losing their function as spacers. The MEMS substrate 50 and the top cover 30 move closer to each other, and the metal frames 54 and 34 come into contact with each other and undergo a eutectic reaction to form a eutectic alloy H12.

[0080] Third Embodiment Next, the structure and manufacturing method of a composite sensor 3 according to a third embodiment will be described with reference to Fig. 12 to Fig. 15. Fig. 12 is a cross-sectional view of the composite sensor according to the third embodiment. Figs. 13 to 15 are cross-sectional views showing the manufacturing process of the composite sensor according to the third embodiment.

[0081] As shown in FIG. 12, in the composite sensor 3, a step is provided on the side of the upper cover 30 facing the MEMS substrate 50, and the thickness of the sealing frame 43 is smaller than the thickness of the sealing frame 44.

[0082] As shown in FIG. 13 , providing the upper cover 30 includes providing a step between the area where the metal frame 33 is provided and the area where the metal frame 34 is provided. Specifically, the area of ​​the glass substrate Q11 where the metal frame 34 is provided is recessed by removing the recess. As a result, even if the heights of the metal frames 33 and 34 are the same, a gap is formed between the metal frames 53 and 34 when they come into contact, as shown in FIG. 14 . As in the manufacturing method of the composite sensor 2 of the second embodiment, step S51 is performed to seal the first space (movable spaces 28, 48) and the second space (movable spaces 29, 49), as shown in FIG. 15 , and a sealing frame 43 and a sealing frame 44 that is thicker than the sealing frame 43 are formed.

[0083] In this embodiment, the step is provided on the top cover 30 side, but the step may be provided on the MEMS substrate 50 side, or steps may be provided on both the MEMS substrate 50 and the top cover 30 side.

[0084] Fourth Embodiment Next, the structure and manufacturing method of a composite sensor 4 according to a fourth embodiment will be described with reference to Fig. 16 and Fig. 17. Fig. 16 is a cross-sectional view of the composite sensor according to the fourth embodiment. Fig. 17 is a cross-sectional view showing a manufacturing process of the composite sensor according to the fourth embodiment.

[0085] 16, in the composite sensor 4, the angular velocity sensor 12 is sealed in the movable spaces 28, 48, and the acceleration sensor 11 is sealed in the movable spaces 29, 49. The degree of vacuum in the movable spaces 28, 48 is higher than the degree of vacuum in the movable spaces 29, 49.

[0086] 17 , the chamber CH is evacuated to a high vacuum, the movable spaces 28 and 48 are temporarily sealed, and then the degree of vacuum in the chamber CH is reduced while a gap is formed between the metal frame 54 and the metal frame 34. Next, the movable spaces 28 and 48 and the movable spaces 29 and 49 are sealed.

[0087] In addition, in this embodiment, the sensors sealed in the first space and the second space are reversed compared to the second embodiment, and the vacuum level is reduced after temporary sealing. However, the above changes may also be applied to the first embodiment or the third embodiment.

[0088] Fifth Embodiment Next, the structure of a composite sensor 5 according to a fifth embodiment will be described with reference to Fig. 18. Fig. 18 is a plan view of the composite sensor according to the fifth embodiment.

[0089] As shown in FIG. 18, the sealing frame 43 and the sealing frame 44 are arranged with a gap therebetween in a plan view.

[0090] Sixth Embodiment Next, the structure of a composite sensor 6 according to a sixth embodiment will be described with reference to Fig. 19. Fig. 19 is a plan view of the composite sensor according to the sixth embodiment.

[0091] 19 , in a plan view, the sealing frame 43 is surrounded by the sealing frame 44. The first space is inside the sealing frame 43, and the second space is outside the sealing frame 43 and inside the sealing frame 44.

[0092] Some or all of the embodiments of the present invention will be described below, but the present invention is not limited to the following descriptions.

[0093] <1> A composite sensor comprising: a first substrate; a second substrate facing the first substrate with a gap therebetween; a first sealing frame sealing a first space between the first substrate and the second substrate; and a second sealing frame sealing a second space between the first substrate and the second substrate; wherein an acceleration sensor is provided in one of the first space or the second space, and an angular velocity sensor is provided in the other space; the degree of vacuum in the first space is different from the degree of vacuum in the second space; and the first sealing frame and the second sealing frame are both made of a eutectic alloy.

[0094] <2> The composite sensor according to <1>, wherein the composition of the eutectic alloy of the first sealing frame is different from the composition of the eutectic alloy of the second sealing frame.

[0095] <3> The composite sensor according to <2>, wherein the eutectic alloy of the first sealing frame and the eutectic alloy of the second sealing frame contain aluminum, and the aluminum content in the eutectic alloy of the first sealing frame is lower than the aluminum content in the eutectic alloy of the second sealing frame.

[0096] <4> The composite sensor according to any one of <1> to <3>, wherein the thickness of the first sealing frame is different from the thickness of the second sealing frame.

[0097] <5> The composite sensor according to any one of <1> to <4>, wherein the metals constituting the eutectic alloy of the first sealing frame include aluminum and germanium, and the metals constituting the eutectic alloy of the second sealing frame include aluminum and germanium.

[0098] <6> The composite sensor according to <5>, wherein the metals constituting the eutectic alloy of the first sealing frame further contain titanium.

[0099] <7> The composite sensor according to any one of <1> to <6>, further comprising a spacer portion provided between the first substrate and the second substrate, wherein the spacer portion has a metal layer made of a metal that forms a eutectic alloy of the first sealing frame and the second sealing frame.

[0100] <8> The composite sensor according to any one of <1> to <7>, wherein, in a plan view of the first substrate, the first sealing frame is surrounded by the second sealing frame.

[0101] <9> The composite sensor according to any one of <1> to <7>, wherein the first sealing frame is arranged adjacent to the second sealing frame with a gap therebetween in a plan view of the first substrate.

[0102] <10> The composite sensor according to any one of <1> to <7>, wherein, in a plan view of the first substrate, the first sealing frame is connected to the second sealing frame.

[0103] <11> A method for manufacturing a composite sensor, comprising: preparing a first substrate and a second substrate facing the first substrate with a gap therebetween; sealing a first space between the first substrate and the second substrate with a first sealing frame; and sealing a second space between the first substrate and the second substrate with a second sealing frame; wherein an acceleration sensor is provided in one of the first space or the second space, and an angular velocity sensor is provided in the other space; the degree of vacuum in the first space is different from the degree of vacuum in the second space; and the first sealing frame and the second sealing frame are both made of a eutectic alloy.

[0104] <12> The method for manufacturing a composite sensor according to <11>, wherein preparing the first substrate includes providing a first metal frame and a second metal frame on a side facing the second substrate, preparing the second substrate includes providing a third metal frame and a fourth metal frame on a side facing the first substrate, sealing the first space with the first sealing frame includes causing a eutectic reaction between the first metal frame and the third metal frame, and sealing the second space with the second sealing frame includes causing a eutectic reaction between the second metal frame and the fourth metal frame.

[0105] <13> The method for manufacturing a composite sensor according to <12>, wherein preparing the second substrate further includes providing a spacer portion on a side facing the first substrate, and further including, after sealing the first space with the first sealing frame and before sealing the second space with the second sealing frame, changing the degree of vacuum in a chamber having the first substrate and the second substrate therein in a state in which the spacer portion abuts against the first substrate to form a gap between the second metal frame and the fourth metal frame.

[0106] <14> The method for manufacturing a composite sensor according to <13>, wherein the spacer portion has the same layer structure as the third metal frame.

[0107] <15> The method for manufacturing a composite sensor according to any one of <12> to <14>, further comprising bringing the first metal frame and the third metal frame into contact at a temperature lower than the eutectic temperature of the eutectic alloy to provisionally seal the first space, and further comprising, after provisionally sealing the first space and before sealing the second space with the second sealing frame, changing the degree of vacuum of a chamber having the first substrate and the second substrate therein in a state in which the third metal frame abuts against the first metal frame to form a gap between the second metal frame and the fourth metal frame.

[0108] <16> The method for manufacturing a composite sensor according to <15>, wherein the thickness of the third metal frame is greater than the thickness of the fourth metal frame.

[0109] <17> The method for manufacturing a composite sensor according to <15>, wherein providing the second substrate includes providing a step between a region where the third metal frame is provided and a region where the fourth metal frame is provided.

[0110] <18> The method for manufacturing a composite sensor according to any one of <12> to <17>, wherein providing the first metal frame and the second metal frame includes providing a germanium layer, and providing the third metal frame and the fourth metal frame includes providing an aluminum layer.

[0111] <19> The method for manufacturing a composite sensor according to <18>, wherein providing the third metal frame further includes providing a titanium layer and providing a second aluminum layer, and providing the fourth metal frame further includes providing a titanium layer.

[0112] As described above, according to one aspect of the present invention, a highly reliable composite sensor with a simple manufacturing process and a manufacturing method thereof can be provided.

[0113] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from its spirit, and such modifications and improvements are also included within the scope of the present invention. In other words, designs modified by those skilled in the art as appropriate are also encompassed within the scope of the present invention as long as they incorporate the characteristics of the present invention. For example, the elements of the present embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those exemplified and can be modified as appropriate. Furthermore, the elements of the present embodiments can be combined to the extent technically possible, and such combinations are also encompassed within the scope of the present invention as long as they incorporate the characteristics of the present invention.

[0114] DESCRIPTION OF SYMBOLS 1...Composite sensor 10...Device layer 11...Acceleration sensor 12...Angular velocity sensor 20...Lower cover 28, 29...Moving space 30...Upper cover 33, 34...Metal frame 40...Joining layer 48, 49...Moving space 43, 44...Sealing frame 45...Spacer portion 46...Contact portion 50...MEMS substrate 53, 54...Metal frame P10, Q10, F10...Silicon substrate P11, G10...Silicon oxide film Q11...Glass substrate H11, H12...Eutectic alloy H31, H33...Aluminum layer H32, H51...Titanium layer H52...Germanium layer GS...Inert gas

Claims

1. A composite sensor comprising: a first substrate; a second substrate facing the first substrate with a gap therebetween; a first sealing frame sealing a first space between the first substrate and the second substrate; and a second sealing frame sealing a second space between the first substrate and the second substrate; an acceleration sensor is provided in one of the first space or the second space and an angular velocity sensor is provided in the other space; the degree of vacuum in the first space is different from the degree of vacuum in the second space; and the first sealing frame and the second sealing frame are both made of a eutectic alloy.

2. The composite sensor according to claim 1, wherein the composition of the eutectic alloy of the first sealing frame is different from the composition of the eutectic alloy of the second sealing frame.

3. The composite sensor according to claim 2, wherein the eutectic alloy of the first sealing frame and the eutectic alloy of the second sealing frame contain aluminum, and the aluminum content in the eutectic alloy of the first sealing frame is smaller than the aluminum content in the eutectic alloy of the second sealing frame.

4. The composite sensor according to claim 1, wherein the thickness of the first sealing frame is different from the thickness of the second sealing frame.

5. A composite sensor according to any one of claims 1 to 4, wherein the metals constituting the eutectic alloy of the first sealing frame include aluminum and germanium, and the metals constituting the eutectic alloy of the second sealing frame include aluminum and germanium.

6. The composite sensor according to claim 5, wherein the metals constituting the eutectic alloy of the first sealing frame further include titanium.

7. A composite sensor as described in any one of claims 1 to 6, further comprising a spacer portion provided between the first substrate and the second substrate, the spacer portion having a metal layer made of a metal that constitutes a eutectic alloy of the first sealing frame and the second sealing frame.

8. The composite sensor according to claim 1, wherein, in a plan view of the first substrate, the first sealing frame is surrounded by the second sealing frame.

9. The composite sensor according to claim 1, wherein, in a plan view of the first substrate, the first sealing frame is arranged adjacent to the second sealing frame with a gap therebetween.

10. A composite sensor as described in any one of claims 1 to 7, wherein, in a plan view of the first substrate, the first sealing frame is connected to the second sealing frame.

11. A method for manufacturing a composite sensor, comprising: preparing a first substrate and a second substrate facing the first substrate with a gap therebetween; sealing a first space between the first substrate and the second substrate with a first sealing frame; and sealing a second space between the first substrate and the second substrate with a second sealing frame; an acceleration sensor is provided in one of the first space or the second space, and an angular velocity sensor is provided in the other space; the degree of vacuum in the first space is different from the degree of vacuum in the second space; and both the first sealing frame and the second sealing frame are made of a eutectic alloy.

12. A method for manufacturing a composite sensor as described in claim 11, wherein preparing the first substrate includes providing a first metal frame and a second metal frame on a side facing the second substrate, preparing the second substrate includes providing a third metal frame and a fourth metal frame on a side facing the first substrate, sealing the first space with the first sealing frame includes causing a eutectic reaction between the first metal frame and the third metal frame, and sealing the second space with the second sealing frame includes causing a eutectic reaction between the second metal frame and the fourth metal frame.

13. A method for manufacturing a composite sensor as described in claim 12, wherein preparing the second substrate further includes providing a spacer portion on a side facing the first substrate, and further includes changing the degree of vacuum of a chamber having the first substrate and the second substrate therein, after sealing the first space with the first sealing frame and before sealing the second space with the second sealing frame, in a state in which the spacer portion abuts against the first substrate to form a gap between the second metal frame and the fourth metal frame.

14. The method for manufacturing a composite sensor according to claim 13, wherein the spacer portion has the same layer structure as the third metal frame.

15. A method for manufacturing a composite sensor described in any one of claims 12 to 14, further comprising contacting the first metal frame with the third metal frame at a temperature lower than the eutectic temperature of the eutectic alloy to provisionally seal the first space, and further comprising, after provisionally sealing the first space and before sealing the second space with the second sealing frame, changing the degree of vacuum of a chamber having the first substrate and the second substrate therein, in a state in which the third metal frame abuts against the first metal frame to form a gap between the second metal frame and the fourth metal frame.

16. The method for manufacturing a composite sensor according to claim 15, wherein the thickness of the third metal frame is greater than the thickness of the fourth metal frame.

17. The method for manufacturing a composite sensor as described in claim 15, wherein providing the second substrate includes providing a step between an area where the third metal frame is provided and an area where the fourth metal frame is provided.

18. A method for manufacturing a composite sensor as described in any one of claims 12 to 17, wherein providing the first metal frame and the second metal frame includes providing a germanium layer, and providing the third metal frame and the fourth metal frame includes providing an aluminum layer.

19. The method for manufacturing a composite sensor as described in claim 18, wherein providing the third metal frame further includes providing a titanium layer and providing a second aluminum layer, and providing the fourth metal frame further includes providing a titanium layer.

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