Inertial sensor, electronic component, and method for manufacturing inertial sensor

Abstract

An inertial sensor, an electronic component, and a method for manufacturing the inertial sensor. An inertial sensor or an electronic component includes: a base; a cover body; the functional element is arranged between the base body and the cover body; and a metal eutectic layer that joins the base body and the lid body around the functional element, the metal eutectic layer having a plurality of first regions that are mainly composed of a first metal and have a face-centered cubic lattice structure and a plurality of second regions that are mainly composed of a second metal and have a diamond structure. The first region and the second region are adjacent to each other.

Description

Technical Field

[0001] The present invention relates to an inertial sensor, an electronic component, and a method for manufacturing the inertial sensor. Background Art

[0002] Conventionally, a sensor device including a substrate having a chamber, a sensor element suspended in the chamber, and a lid for sealing the chamber has been known. The substrate and the lid are joined by a joining material. For the joining material, high joining strength and high long-term reliability of sealing have been sought.

[0003] For example, Patent Document 1 discloses using an AlGe eutectic as the joining material. According to this document, the concentration of Ge in the AlGe eutectic is uniform or a function of the distance from the lid or the substrate. In particular, it is disclosed that the concentration of Ge becomes uniform when a long-time heat treatment is performed.

[0004] Prior Art Documents

[0005] Patent Document 1: U.S. Patent Application Publication No. 2010 / 0059835

[0006] However, in the technology of Patent Document 1, the joining strength based on the joining material may decrease. In addition, the long-term reliability of the seal may decrease. Specifically, if the concentration of Ge decreases according to the distance from the lid, AlGe eutectic formation cannot be achieved on the substrate side, and only an Al layer is formed, which may reduce the joining strength. In addition, although long-time heat treatment is preferable for forming a joining layer with a uniform Ge concentration, hillocks or the like are generated in other metal wirings, such as Al wirings for extracting detection signals, resulting in a reduction in long-term reliability.

[0007] That is, there has been a demand for an inertial sensor, an electronic component, and a method for manufacturing an inertial sensor having high joining strength between a substrate and a lid and excellent long-term reliability. Summary of the Invention

[0008] An inertial sensor according to one aspect of the present application is an electrostatic capacitance change type inertial sensor, including: a substrate; a lid; a functional element provided between the substrate and the lid; and a metal eutectic layer that joins the substrate and the lid around the functional element, the metal eutectic layer having a plurality of first regions mainly composed of a first metal and having a face-centered cubic lattice structure and second regions mainly composed of a second metal and having a diamond structure, and the first regions and the second regions being adjacent to each other.

[0009] An electronic component according to one aspect of the present application includes: a substrate; a lid; a functional element disposed between the substrate and the lid; and a metal eutectic layer that joins the substrate and the lid around the functional element. The metal eutectic layer has a plurality of first regions mainly composed of a first metal and having a face-centered cubic lattice structure, and second regions mainly composed of a second metal and having a diamond structure, and the first regions and the second regions are adjacent to each other.

[0010] A method of manufacturing an inertial sensor according to one aspect of the present application is a manufacturing method of joining a substrate provided with a functional element and a lid covering the functional element in a joining region surrounding the functional element. The manufacturing method includes the following steps: forming a first joining portion mainly composed of a first metal in the joining region in the substrate; forming a second joining portion mainly composed of a second metal in the joining region in the lid; aligning the first joining portion and the second joining portion so as to overlap, and overlapping the substrate and the lid to form a laminate; a heating step of heating the laminate; and a weighting step of applying a weight to the laminate. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a top view of the inertial sensor according to Embodiment 1.

[0012] Figure 2 is Figure 1 a cross-sectional view of the inertial sensor taken along the b-b section of

[0013] Figure 3 is Figure 2 an enlarged view of part c of

[0014] Figure 4 is a main part cross-sectional view of the substrate and the lid before joining.

[0015] Figure 5 is a table showing the relationship of surface energy per unit area.

[0016] Figure 6 is a flowchart showing the process of the joining method.

[0017] Figure 7 is a side view showing the schematic structure of the joining device.

[0018] Figure 8 is a graph showing an example of the temperature curve in the heating step.

[0019] Figure 9 is a perspective view showing the main part of the electrical wiring structure of the metal eutectic layer.

[0020] Figure 10It is a main part cross-sectional view of the substrate and the cover before joining according to Embodiment 2.

[0021] Figure 11 It is a main part cross-sectional view of the substrate and the cover before joining according to Embodiment 3.

[0022] Figure 12 It is an enlarged view of the periphery of the metal eutectic layer after joining.

[0023] Figure 13 It is a top view of the inertial sensor according to Embodiment 4.

[0024] Figure 14 It is an exploded perspective view of the inertial measurement device.

[0025] Figure 15 It is a perspective view of the substrate.

[0026] Reference numeral description

[0027] 1: Substrate; 2: Insulating layer; 3: Semiconductor layer; 5: Recess; 6: Insulating layer; 7: Wiring layer; 8: Insulating layer; 10: Substrate body; 11: Protrusion; 12: Barrier layer; 13: First metal layer; 15: First joint; 15b: Protrusion; 16: Second joint; 16b: Second joint; 18: Contact part; 19: Table; 20: Metal eutectic layer; 20a: Joint area; 21: First area; 22: Second area; 22a, 22b: Extension; 26: Joint layer; 27: Barrier layer; 28: Second joint; 30: Cover; 31: Stopper; 35: Recess; 36: Sealing hole; 37: Solder ball; 41: Heating jig; 41h: Heating heater; 41s: Workbench; 42: Weighting jig; 42h: Heating heater; 42s: Workbench; 43, 44, 45: Curve; 48: Joining device; 52a: First rod; 52b: Second rod; 53: Third rod; 54a: First rotary spring; 54b: Second rotary spring; 55: Movable body; 60: Center line; 61: Swing axis; 65: Fixed part; 71, 71c: Movable electrode; 72, 72c: Fixed electrode; 73a - 73d: Movable electrode group; 74a - 74d: Fixed electrode group; 75a - 75d: Support part; 76n: N-type detection part; 76p: P-type detection part; 80: Sensor element; 81 - 84: Wiring; 85: Sensor element; 86: Sensor element; 91 - 94: Terminal; 99: Stacked body; 100: Inertial sensor; 110: Inertial sensor; 301: Housing; 302: Threaded hole; 310: Joining component; 315: Substrate; 316: Connector; 317x: Angular velocity sensor; 317y: Angular velocity sensor; 317z: Angular velocity sensor; 320: Inner housing; 321: Opening; 325: Sensor module; 331: Recess; 2000: Inertial measurement device. Detailed implementation mode

[0028] Embodiment 1

[0029] ***Structure of inertial sensor***

[0030] Figure 1 is a top view of the inertial sensor related to Embodiment 1. Figure 2 is Figure 1 a cross-sectional view of the inertial sensor at the b-b section of

[0031] Use Figure 1 , Figure 2 to describe the structure of the inertial sensor 100 related to this embodiment.

[0032] The inertial sensor 100 is, for example, an acceleration sensor that detects the acceleration in the vertical direction. In addition, in each figure, three mutually perpendicular axes, namely the X-axis, the Y-axis, and the Z-axis, are illustrated. In the present embodiment, the Z-axis direction is set as the vertical direction, but it is not limited thereto. The direction along the X-axis is referred to as the "X direction", the direction along the Y-axis is referred to as the "Y direction", and the direction along the Z-axis is referred to as the "Z direction". In addition, the end side of the arrow in each axis direction is also referred to as the "positive side", and the base end side of the arrow is referred to as the "negative side". For example, the Y direction refers to both the positive side and the negative side of the Y direction. In addition, the positive side of the Z direction is also referred to as "up", and the negative side of the Z direction is referred to as "down". In addition, in the following figures, for the sake of easy understanding of the description, the figures are sometimes drawn in different sizes and scales from the actual ones.

[0033] The inertial sensor 100 is a uniaxial acceleration sensor composed of a MEMS (Micro Electro Mechanical Systems) device. In addition, it is not limited to an acceleration sensor, and as long as it is an inertial sensor of the electrostatic capacitance change type, it can also be, for example, an angular velocity sensor.

[0034] As Figure 2 shown, the inertial sensor 100 is composed of a base 10, a sensor element 80 disposed on the base 10, a wiring layer 7 led out from the sensor element 80, a cover 30 covering the sensor element 80, and the like.

[0035] The base 10 is a SOI (Silicon On Insulator) substrate, and is formed by laminating a substrate 1, an insulating layer 2, a semiconductor layer 3, and a wiring layer 7 in this order along the Z direction. The substrate 1 is a single crystal silicon substrate, and an insulating layer 2 is provided on its upper surface. The insulating layer 2 is a buried insulating layer made of SiO2.

[0036] A recess 5 is provided in the substrate 1 and is dug downward from the peripheral portion. The recess 5 is a chamber and is a part of the accommodation space S for accommodating the sensor element 80. Through the recess 5, the movable body 55 of the sensor element 80 ( Figure 1 ) becomes a structure capable of swinging. In addition, in Figure 2 , an insulating layer 2 is provided on the bottom surface of the recess 5, but an insulating layer 2 may not be provided on the bottom surface of the recess 5.

[0037] The semiconductor layer 3 is, for example, a conductive silicon substrate doped with impurities such as phosphorus (P), boron (B), and arsenic (As). In a preferred example, the semiconductor layer 3 and the insulating layer 2 are joined by Si-SiO2 fusion bonding.

[0038] The sensor element 80 is a functional element formed by etching and patterning the semiconductor layer 3. In a preferred example, a deep etching technique based on the Bosch process is used. The sensor element 80 is fixed to the substrate 1 by means of a fixing portion 65 ( Figure 1 ).

[0039] As a preferred example, the cover body 30 uses a silicon substrate. A recess 35 is provided in the cover body 30 by digging downward from the peripheral portion. The recess 35 is a part of the accommodation space S for accommodating the sensor element 80. A convex portion, i.e., a stopper portion 31, for restricting the excessive swing of the movable body 55 of the sensor element 80 is provided in the recess 35.

[0040] The base body 10 and the cover body 30 are joined at their peripheral portions by a metal eutectic layer 20. In a preferred example, the accommodation space S is filled with an inert gas such as nitrogen, helium, or argon and is hermetically sealed. In addition, in a use temperature environment of around -40°C to 120°C, it is preferably in a state of approximately atmospheric pressure or vacuum. For example, when the sensor element 80 is an acceleration sensor, it is better for the accommodation space S to be at a pressure close to atmospheric pressure, and when the sensor element 80 is an angular velocity sensor, it is better for the accommodation space S to be at a vacuum pressure.

[0041] ***Structure of the sensor element***

[0042] As Figure 1 shown, the sensor element 80, which is a functional element, is an acceleration sensor for detecting acceleration in the Z direction and adopts a so-called single-sided seesaw structure in which the movable body 55 swings about a swing axis 61.

[0043] The sensor element 80 is composed of a fixing portion 65, a movable body 55 that can swing about a swing axis 61 passing through the center of the fixing portion 65 and along the Y axis, and first and second torsion springs 54a, 54b, etc. that connect the fixing portion 65 and the movable body 55. The fixing portion 65 is fixed to an unillustrated pedestal portion protruding from the substrate 1 ( Figure 2 ). A recess 5 ( Figure 2 ) is formed around the pedestal portion, and the movable body 55 is configured to be able to swing. In addition, in Figure 1 , a line segment perpendicular to the swing axis 61 and passing through the center of the sensor element 80 along the X axis is defined as the center line 60.

[0044] The movable body 55 has a first rod 52a extending in the positive X direction from the first torsion spring 54a, a second rod 52b extending in the positive X direction from the second torsion spring 54b, and a third rod 53 connecting the first rod 52a and the second rod 52b.

[0045] Four movable electrode groups 73a to 73d in a comb shape are provided on the third rod 53.

[0046] The movable electrode group 73a is composed of six movable electrodes 71c extending from the third rod 53 in the positive X direction on the negative Y side of the center line 60.

[0047] The movable electrode group 73b is composed of six movable electrodes 71c extending from the third rod 53 in the negative X direction on the negative Y side of the center line 60. In addition, the number of the movable electrodes 71c is not limited to six, and as long as it is plural.

[0048] The movable electrode groups 73c and 73d are provided at positions line-symmetric with the movable electrode groups 73a and 73b on the positive Y side with the center line 60 as the axis of symmetry.

[0049] Moreover, on the substrate 1 ( Figure 2 ) side, fixed electrode groups 74a to 74d opposed to the movable electrode groups 73a to 73d are provided.

[0050] The fixed electrode group 74a is composed of a support portion 75a fixed to the substrate 1 and seven fixed electrodes 72 extending from the support portion 75a in the negative X direction.

[0051] The fixed electrode group 74b is composed of a support portion 75b fixed to the substrate 1 and seven fixed electrodes 72 extending from the support portion 75b in the positive X direction. In addition, the number is not limited to seven, and as long as it is the number corresponding to the number of the movable electrodes 71c.

[0052] The fixed electrode groups 74c and 74d are provided at positions line-symmetric with the fixed electrode groups 74a and 74b on the positive Y side with the center line 60 as the axis of symmetry.

[0053] The detection portions based on the fixed electrode group 74a and the movable electrode group 73a, and the detection portions based on the fixed electrode group 74b and the movable electrode group 73b are collectively referred to as the N-type detection portion 76n.

[0054] In the N-type detection portion 76n, a parallel plate type capacitor is formed by the opposed fixed electrode 72 and movable electrode 71c. This capacitor changes according to the change in the overlapping area with the fixed electrode 72 as the displacement of the movable electrode 71c caused by acceleration.

[0055] Similarly, the detection portions based on the fixed electrode group 74c and the movable electrode group 73c, and the detection portions based on the fixed electrode group 74d and the movable electrode group 73d are collectively referred to as the P-type detection portion 76p. In the P-type detection portion 76p, a parallel plate type capacitor is formed by the opposed fixed electrode 72c and movable electrode 71. This capacitor changes according to the change in the overlapping area with the fixed electrode 72c as the displacement of the movable electrode 71 caused by acceleration.

[0056] The movable electrode 71c of the N-type detection section 76n is thinner in the Z direction than the movable electrode 71 of the P-type detection section 76p. Specifically, the movable electrode 71c is cut into a stepped shape and thinned from the same thickness as the third rod 53 at the root in the middle of the extending direction. As a result, the thickness on the positive Z side of the 12 movable electrodes 71c becomes thinner at the portion facing the fixed electrode 72.

[0057] The fixed electrode 72c of the P-type detection section 76p is thinner in the Z direction than the fixed electrode 72 of the N-type detection section 76n. Specifically, the fixed electrode 72c is cut into a stepped shape and thinned from the thickness at the root on the support section 75c, 75d side in the middle of the extending direction. As a result, the thickness on the positive Z side of the 14 fixed electrodes 72c becomes thinner at the portion facing the movable electrode 71.

[0058] According to such a structure, when an acceleration is generated in the positive Z direction, the overlapping area decreases in the N-type detection section 76n, and the overlapping area is maintained in the P-type detection section 76p. In addition, when an acceleration in the negative Z direction is generated, the overlapping area is maintained in the N-type detection section 76n, and the overlapping area decreases in the P-type detection section 76p.

[0059] Based on such a correlation, in the sensor element 80, by differentially detecting the change in the overlapping area in the N-type detection section 76n and the P-type detection section 76p as a change in electrostatic capacitance, the acceleration in the positive / negative Z directions can be detected.

[0060] ***Top view shape of the bonding region***

[0061] As Figure 1 shown, the base 10 is substantially rectangular, and the short side in the negative X direction forms an extending portion 11 that extends from the short side of the lid 30. Terminals 91 to 94 for external connection are provided on the extending portion 11.

[0062] The terminal 91 is a movable electrode terminal and is electrically connected to all the movable electrodes 71, 71c through the wiring 81.

[0063] The terminal 92 is an N-type fixed electrode terminal and is electrically connected to all the fixed electrodes 72 of the N-type detection section 76n through the wiring 82.

[0064] The terminal 93 is a P-type fixed electrode terminal and is electrically connected to all the fixed electrodes 72c of the P-type detection section 76p through the wiring 83.

[0065] The terminal 94 is a GND terminal and is electrically connected to the metal eutectic layer 20 through the wiring 84. In addition, the details of the connection method between the terminal 94 and the metal eutectic layer 20 will be described later.

[0066] The base body 10 and the lid body 30 are joined at a four-sided annular joining region 20a surrounding the sensor element 80. The joining region 20a is a four-sided annular region that is one circle smaller than the outer peripheral edge of the lid body 30. A metal eutectic layer 20 is formed in the joining region 20a. Further, the metal eutectic layer 20 is formed to cross the wirings 81 to 83 in a plan view.

[0067] In other words, the capacitance-variable type inertial sensor 100 includes: a base body 10, a lid body 30, a sensor element 80 as a functional element provided between the base body 10 and the lid body 30, a wiring layer 7 laminated on the sensor element 80, and a metal eutectic layer 20 that joins the base body 10 and the lid body 30 around the sensor element 80.

[0068] ***Details of the metal eutectic layer***

[0069] Figure 3 is Figure 2 an enlarged view of part c. Figure 4 is a main part cross-sectional view of the base body and the lid body before joining, corresponding to Figure 2 corresponds.

[0070] Figure 3 The cross-section of the overlapping part of the joining region 20a and the wiring 82 connected to the terminal 92 is shown. An insulating layer 6, a wiring layer 7 including the wiring 82, an insulating layer 8, a barrier layer 12, a metal eutectic layer 20, and a lid body 30 are laminated in this order on the base body 10.

[0071] The insulating layer 6 is an interlayer insulating layer, and is a SiO2 layer in a preferred example. Further, the insulating layer 6 may also be a SiN layer. The same applies to the insulating layer 8.

[0072] The wiring layer 7 is formed of multiple layers, and is, for example, a four-layer structure laminated in order from the bottom with Ti, TiN, AlCu, and TiN.

[0073] Here, the barrier layer 12 refers to a double-layer structure of Ti and TiN, and is the structure remaining as the base layer of the first joint portion 15 ( Figure 4 ) on the base body 10 side before forming the metal eutectic layer 20. The Ti layer functions to improve the adhesion to the insulating layer 8, and the TiN layer functions to prevent Al from diffusing from the AlCu. If the adhesion of the barrier layer 12 to the insulating layer 8 is good, the Ti layer can be omitted.

[0074] As Figure 4As shown, before forming the metal eutectic layer 20, a first joint portion 15 is provided on the substrate 10, and a second joint portion 16 is provided on the cover 30. The first joint portion 15 has a double-layer structure of a barrier layer 12 and a first metal layer 13. The barrier layer 12 has a double-layer structure of Ti and TiN, and the first metal layer 13 is an AlCu layer. The second joint portion 16 is a Ge layer as the second metal layer. Among them, Cu in the AlCu layer is mixed in to prevent electromigration, and the content rate is low as described later. Therefore, the main component of the first metal layer 13 is Al. On the other hand, the second joint portion 16 is a Ge layer as the second metal layer. The second joint portion 16 is also referred to as the second metal layer 16. In other words, the main component of the first metal is Al, and the main component of the second metal is Ge.

[0075] The metal eutectic layer 20 is a eutectic layer formed by eutecticizing and joining the first joint portion 15 and the second joint portion 16 through the joining method described later. Eutectic generally refers to an alloy formed by solidifying two or more metals from a mixed liquid phase state.

[0076] Figure 3 The shown metal eutectic layer 20 is obtained by truthfully tracing a micrograph of the eutectic layer.

[0077] As a result of elemental analysis, as Figure 3 shown, the metal eutectic layer 20 is formed with a first region 21 mainly composed of Al as the first metal and a second region 22 mainly composed of Ge as the second metal in an adjacent state. The content rate of the first metal in the first region 21 is higher than that of the first metal in the second region 22. The content rate of the second metal in the second region 22 is higher than that of the second metal in the first region 21.

[0078] The second region 22 extends widely along the cover 30, but a part of it reaches the boundary between the metal eutectic layer 20 and the substrate 10. For example, in Figure 3 it, the extension portions 22a, 22b reach the substrate 10. The boundary between the first region 21 and the second region 22 has many irregularities and is intricately entangled with each other. In addition, regarding the part extending from the cover 30 to the substrate 10, the second region 22 is more than the first region 21.

[0079] The distribution of Ge in the metal eutectic layer 20 is not uniform, and it exists more in the second region 22, and is uniform and has no concentration gradient within this region. However, in the first region 21, although in small amounts, Ge also exists uniformly. The first region 21 and the second region 22 are in contact with each other without gaps, and their contact area is larger than the planar area of the joint region 20a. That is, the first region 21 and the second region 22 are randomly interlocked, and their joint strength is very high. In other words, the contact area between the first region 21 and the second region 22 is larger than the area of the joint region 20a where the substrate 10 and the cover 30 are joined through the metal eutectic layer 20.

[0080] Figure 5 It is a table showing the relationship of the surface energy per unit area. In addition, Figure 5 The source of Table 19 is based on: Yokota et al., Precision Engineering 31(10) (1965) pp.828 - 835, and H.W.Sheng et al., PhysRevB.83.134118(2011).

[0081] Generally, it is known that Ge has a diamond structure and Al has a face - centered cubic lattice structure. As the main components of the eutectic layer, if there is more Ge, a solid solution with a diamond structure is formed, and if there is more Al, a solid solution with a face - centered cubic lattice structure is formed. A solid solution refers to a substance in which two elements are fused and the whole becomes a solid phase with a relatively uniform concentration. However, each solid solution has different composition ratios within the solid solubility limit.

[0082] That is, the second region 22 with more Ge realizes a solid solution with a diamond structure, and the first region 21 with more Al realizes a solid solution with a face - centered cubic lattice structure. When the crystal is cut to expose the surface, the target is the surface energy. As Figure 5 shown in Table 19, it can be seen that for the surface energy per unit area, if Ge and Al are compared, Ge is higher in any crystal plane orientation. In other words, the metal eutectic layer 20 has a plurality of first regions 21 mainly composed of the first metal and having a face - centered cubic lattice structure and second regions 22 mainly composed of the second metal and having a diamond structure, and the first region 21 and the second region 22 are adjacent.

[0083] As Figure 3 shown, a part of the second region 22 reaches the boundary between the metal eutectic layer 20 and the substrate 10. Moreover, the second region 22 extends from the cover body 30 to the substrate 10. In other words, the second region 22 reaches the boundary between the metal eutectic layer 20 and the substrate 10. That is, the second region 22 reaches the substrate 10 regardless of the distance from the cover body 30. At the same time, the second region 22 with more Ge contains Al within the solid solubility limit with respect to Ge. Moreover, the composition ratio of Ge and Al in the second region 22 is relatively uniform and does not depend on the distance from the cover body 30. From the viewpoint of surface energy, when the second region 22 with more Ge reaches the boundary between the metal eutectic layer 20 and the substrate 10, the bonding strength is high. More preferably, it is better when the part of the second region 22 with more Ge extending from the cover body 30 to the substrate 10 is larger.

[0084] On the other hand, at the boundary between the cover body 30 and the metal eutectic layer 20 in Figure 3 , a second joint portion 16 made of Ge is directly formed on the cover body 30 ( Figure 4), so Ge diffuses into the silicon that serves as the lid 30. That is, the second region 22 mainly composed of Ge forms a fine concavo-convex shape at the boundary portion ( Figure 3 the dashed line in) with the lid 30, increasing the contact area and raising the bonding strength.

[0085] ***Bonding method of the bonding region***

[0086] Figure 6 is a flowchart showing the process of the bonding method.

[0087] Here, regarding the bonding method of the base 10 and the lid 30, Figure 6 is the main body, and will be described appropriately in combination with other drawings.

[0088] In step S10, the first bonding portion 15 is formed on the base 10. In addition, before step S10, the case where the base 10 formed with the sensor element 80 included is described.

[0089] As Figure 4 shown, the first bonding portion 15 has a double-layer structure of the barrier layer 12 and the first metal layer 13. In a preferred example, the barrier layer 12 has a double-layer structure of Ti and TiN. The first metal layer 13 is an AlCu layer. In a preferred example, the content concentration of Cu is 0.1 to 1.0 wt%, and the layer thickness is about The first bonding portion 15 is formed, for example, after being formed by DC sputtering and patterned corresponding to the bonding region 20a.

[0090] In step S11, the second bonding portion 16 is formed on the lid 30. In addition, before step S11, the case where the lid 30 formed with the recess 35 included is described. Additionally, the formation of the base 10 and the lid 30 can also be carried out in parallel in other processes.

[0091] As Figure 4 shown, the second bonding portion 16 is a Ge layer as the second metal layer. In the present embodiment, the second bonding portion 16 made of Ge is directly formed on the silicon substrate constituting the lid 30. In a preferred example, after forming a Ge layer of about by DC sputtering, it is patterned corresponding to the bonding region 20a to form the second bonding portion 16. In addition, as long as the desired film thickness can be obtained for the formation of the first bonding portion 15 and the second bonding portion 16, the RF sputtering method can also be used.

[0092] Figure 7 is a side view showing the schematic structure of the bonding device. In addition, for the sake of convenience in explanation, before bonding, the state obtained by overlapping the base 10 and the lid 30 is called the laminate 99.

[0093] The bonding device 48 is disposed in a chamber (not shown) and is composed of a heating jig 41, a weighting jig 42, etc. The heating jig 41 includes a metal workbench 41s for placing the laminate 99 and a heating heater 41h such as a sheathed heater. The weighting jig 42 includes a workbench 42s opposed to the workbench 41s and a heating heater 42h such as a sheathed heater. In addition, the heating heater is not limited to a sheathed heater, and any heater capable of heating may be used. For example, a carbon heater may also be used.

[0094] In step S12, the position of the bonding region 20a is aligned to obtain a state of the laminate 99 in which the substrate 10 and the cover 30 are overlapped, and then it is set on the heating jig 41 of the bonding device 48. Specifically, as Figure 7 shown, the laminate 99 with the substrate 10 facing downward is placed on the workbench 41s of the heating jig 41. In addition, it may be placed on the heating jig 41 with the cover 30 facing downward. Alternatively, after the alignment of the bonding region 20a, the substrate 10 and the cover 30 may be temporarily fixed using fixing pins (not shown).

[0095] In this step S12, the weighting jig 42 is not in contact with the laminate 99 and is in a separated state. In addition, the laminate 99 may be in a state of a large substrate on which a plurality of sensor elements 80 are arranged. Therefore, the substrate 10 and the cover 30 may have the same size. Additionally, it is preferable that moisture is removed as much as possible in the chamber to form an environment filled with an inert gas such as N2 or Ar. Alternatively, it may be set to an atmospheric pressure state, or it may be depressurized to a vacuum state. For example, when the sensor element 80 is an acceleration sensor, the chamber is preferably in an atmospheric pressure state. This is because the damping effect based on the atmospheric pressure sometimes improves the characteristics of the acceleration sensor. Additionally, when the sensor element 80 is an angular velocity sensor, it is preferable that the pressure is in a vacuum state of 0.1 to 10 Pa. This is because the vibration characteristics become good in such a vacuum state.

[0096] Figure 8 is a graph showing an example of the temperature curve in the heating process. The horizontal axis represents the elapsed time (minutes), the left vertical axis represents the temperature (°C), and the right vertical axis represents the weighting (arbitrary unit).

[0097] In Figure 8 it, the curve 43 shows the set temperature of the heating jig 41, the curve 44 shows the set temperature of the weighting jig 42. The curve 45 shows the temperature of the laminate 99. The curve 47 shows the application state of the weighting.

[0098] In step S13, the heating process of the heating and bonding device 48 is performed. In the heating process, both the heating jig 41 and the weighting jig 42 are heated using a first set temperature of 400 °C or higher. In addition, the eutectic temperature of AlGe is 420 °C.

[0099] Figure 8 An example of the temperature curve in the preferred example is shown. As shown by curve 43, in the heating jig 41, 425 °C is set as the first set temperature. In addition, it is not limited to 425 °C, and any temperature from 415 °C to 425 °C is acceptable.

[0100] In addition, as shown by curve 44, in the weighting jig 42, 445 °C is set as the first set temperature. In addition, it is not limited to 445 °C, and any temperature from 420 °C to 450 °C is acceptable.

[0101] In step S14, it is determined whether the temperature of the laminate 99 has stabilized through heating based on the first set temperature. If the temperature has stabilized, the process proceeds to step S15. If the temperature has not stabilized, the heating based on the first set temperature in step S13 continues. In Figure 8 this case, as shown by curve 45, the temperature has stabilized at approximately 435 °C, so the process proceeds to step S15. At this time, the temperature of the laminate 99 exceeds the eutectic temperature of AlGe, which is 420 °C, but no weighting is applied, so the formation of the metal eutectic layer 20 of AlGe does not proceed significantly and is limited. As the first set temperature, 425 °C is set in the heating jig 41 and 445 °C is set in the weighting jig 42, thereby enabling sufficient heat to be transferred to the laminate 99.

[0102] In step S15, the heating setting is changed to a second set temperature lower than the first set temperature. In Figure 8 this case, the heating jig 41 is changed from 425 °C of the first set temperature to 415 °C of the second set temperature. In addition, it is not limited to 415 °C, and any temperature from 410 °C to 420 °C is acceptable. Similarly, the weighting jig 42 is changed from 445 °C of the first set temperature to 425 °C of the second set temperature. In addition, it is not limited to 425 °C, and any temperature from 410 °C to 430 °C is acceptable.

[0103] In this step S15, the purpose of changing the heating setting to the second set temperature lower than the first set temperature is to prevent the temperature of the laminate 99 from rising excessively when the weight application jig 42 is brought into contact with the laminate 99. In addition, it is estimated that one reason for the excessive temperature rise is that the heat dissipation area disappears due to the close contact between the weight application jig 42 and the laminate 99. If the temperature of the laminate 99 rises excessively, there is a case where the metal eutectic layer 20 rapidly liquefies and overflows the designed bonding area 20a. By making the second set temperature lower than the first set temperature in this way, the rapid liquefaction phenomenon and overflow of the metal eutectic layer 20 can be prevented.

[0104] In step S16, the weight application jig 42 is lowered to contact the laminate 99, and a specified weight is applied for a specified time. When the cover 30 is on the upper side of the laminate 99, the weight application jig 42 contacts the cover 30, and when the base 10 is on the upper side of the laminate 99, the weight application jig 42 contacts the base 10. As shown by the curve 47 in Figure 8 , the weight is applied after the set temperature drops. In the case of Figure 8 , a load of about 100 is applied for a specified time in arbitrary units. In addition, as shown by the curve 45, the temperature of the laminate 99 drops to about 425 °C before the weight is applied, and gradually rises synchronously with the application of the weight until it reaches about 433 °C.

[0105] In step S17, the heating setting is changed to the third set temperature lower than the second set temperature. In the case of Figure 8 , the heating jig 41 is changed from 415 °C of the second set temperature to 100 °C of the third set temperature. In addition, it is not limited to 100 °C, and for example, it can also be room temperature. Similarly, the weight application jig 42 is changed from 425 °C of the second set temperature to 100 °C of the third set temperature. In addition, it is not limited to 100 °C, and for example, it can also be room temperature. At this time, after the temperature of the laminate 99 is lower than the eutectic temperature 420 °C of AlGe, the weight is released. That is, the specified time of the weight application ends after the temperature becomes 420 °C or lower of the eutectic temperature. Thereby, the eutectic reaction can be suppressed in a short time, and the generation of mounds in the wiring layer 7 including the wirings 81 to 83 can be suppressed. Therefore, the inertial sensor 100 with long-term reliability can be provided.

[0106] According to the above bonding method, the metal eutectic layer 20 shown in Figure 3 is formed in the bonding area 20a, and the base 10 and the cover 30 are firmly bonded, and the inertial sensor 100 is completed. In particular, by performing the heating process and the weight application process based on the above temperature curve 4, good eutectic bonding can be achieved without leaving an unreacted layer of Al or Ge in the eutectic layer.

[0107] In other words, a manufacturing method in which a substrate 10 provided with a sensor element 80 and a cover 30 covering the sensor element 80 are joined in a joining region 20a surrounding the sensor element 80, the manufacturing method including the following steps: forming a first joining portion 15 mainly composed of a first metal in the joining region 20a in the substrate 10; forming a second joining portion 16 mainly composed of a second metal in the joining region 20a in the cover 30; overlapping the substrate 10 and the cover 30 such that the first joining portion 15 and the second joining portion 16 overlap to form a laminate 99; a heating step of heating the laminate 99; and a weighting step of applying a weight to the laminate 99. Further, in the heating step, heating is started at a first set temperature, and after the temperature of the laminate 99 stabilizes, the heating setting is changed to a second set temperature lower than the first set temperature, and then the weighting step is performed. Then, when the weighting step ends, the temperature setting is changed to a third set temperature lower than the second set temperature.

[0108] ***Potential of the cover***

[0109] Figure 9 is a perspective view showing a main part of the electrical wiring structure of the metal eutectic layer, and is Figure 1 an enlarged perspective view around the terminal 94.

[0110] As Figure 9 shown, the metal eutectic layer 20 is electrically connected to a terminal 94 serving as a GND terminal through a protruding portion 15b of the first joining portion 15 ( Figure 4 ). The protruding portion 15b is a wiring pattern formed together with the first joining portion 15 and extends from the joining region 20a toward the terminal 94 side. Since there is no opposing portion on the side of the second joining portion 16 ( Figure 4 ) in the protruding portion 15b, it functions as an electrical wiring led out from the metal eutectic layer 20.

[0111] The protruding portion 15b is provided so as to overlap a wiring 84 connected to the terminal 94 with an insulating layer 8 interposed therebetween. A conductive contact portion 18 is provided at a portion where the wiring 84 and the protruding portion 15b overlap in the insulating layer 8.

[0112] Accordingly, the terminal 94 and the metal eutectic layer 20 are electrically connected via the wiring 84, the contact portion 18, and the protruding portion 15b. In addition, it is not limited to the GND potential, and any electrically stable potential may be used. For example, as long as it is a constant potential including a power supply potential. In other words, the cover 30 is electrically connected to the power wiring of the substrate 10 via the metal eutectic layer 20.

[0113] In addition, in the above description, the sensor element 80 is described as an acceleration sensor in the Z direction, but it is not limited thereto. Any electronic component that requires an airtight environment can be used. For example, it can also be an MEMS device such as an angular velocity sensor, a quartz oscillator, a ceramic oscillator element, or other timing devices.

[0114] As described above, according to the inertial sensor 100 and the manufacturing method of the inertial sensor 100 of the present embodiment, the following effects can be obtained.

[0115] The inertial sensor 100 is an electrostatic capacitance change type inertial sensor, and includes: a base body 10; a cover body 30; a sensor element 80, which is a functional element and is disposed between the base body 10 and the cover body 30; and a metal eutectic layer 20, which joins the base body 10 and the cover body 30 around the sensor element 80. The metal eutectic layer 20 has a plurality of first regions 21 mainly composed of a first metal and having a face-centered cubic lattice structure, and second regions 22 mainly composed of a second metal and having a diamond structure, and the first region 21 and the second region 22 are adjacent to each other.

[0116] Thus, the base body 10 and the cover body 30 are joined by the metal eutectic layer in which the first region 21 composed of the face-centered cubic lattice structure and the second region 22 composed of the diamond structure are randomly intercalated, so that high joining strength can be obtained. Furthermore, the entire region of the joining region 20a is AlGe eutecticized, so the reliability is excellent.

[0117] Therefore, an inertial sensor 100 with high joining strength between the base body 10 and the cover body 30 and excellent long-term reliability can be provided.

[0118] In addition, the second region 22 reaches the boundary between the metal eutectic layer 20 and the base body 10.

[0119] Thus, the second region 22 with a large amount of Ge reaches the boundary between the metal eutectic layer 20 and the base body 10, so the joining strength in the joining region 20a becomes high.

[0120] In addition, the second region 22 extends from the cover body 30 to the base body 10.

[0121] Thus, the joining strength in the joining region 20a becomes even higher.

[0122] In addition, regarding the part extending from the cover body 30 to the base body 10, the second region 22 is more than the first region 21. Thus, the extended part of the second region 22 with a large amount of Ge is more, so the joining strength in the joining region 20a becomes high.

[0123] In addition, the contact area between the first region 21 and the second region 22 is larger than the area of the joining region 20a where the base body 10 and the cover body 30 are joined by the metal eutectic layer 20.

[0124] Thus, since the first region 21 and the second region 22 are randomly fitted with a large contact area, their bonding strength becomes very high.

[0125] In addition, the cover 30 is electrically connected to the power supply wiring of the base 10 via the metal eutectic layer 20. Thus, since the cover 30 becomes the power supply potential and is electrically stable, it is not easily affected by noise, and the operation of the sensor element 80 can be stabilized.

[0126] In addition, the first metal is Al and the second metal is Ge.

[0127] Thus, a metal eutectic layer 20 with high bonding strength can be formed.

[0128] The manufacturing method of the inertial sensor 100 is a manufacturing method of bonding the base 10 provided with the sensor element 80 and the cover 30 covering the sensor element 80 in the bonding region 20a surrounding the sensor element 80. The manufacturing method includes the following steps: forming a first bonding portion 15 mainly composed of the first metal in the bonding region 20a of the base 10; forming a second bonding portion 16 mainly composed of the second metal in the bonding region 20a of the cover 30; aligning the first bonding portion 15 and the second bonding portion 16 to overlap, and overlapping the base 10 and the cover 30 to form a laminate 99; a heating step of heating the laminate 99; and a weighting step of applying a weight to the laminate 99.

[0129] According to this manufacturing method, the temperature and weight required for forming the eutectic layer can be applied through the heating step and the weighting step. Thus, a metal eutectic layer 20 with high bonding strength can be formed in the bonding region 20a.

[0130] In addition, after the temperature of the laminate 99 is stabilized by the heating step set at the first set temperature, the temperature setting is changed to the second set temperature lower than the first set temperature, and then the weighting step is performed.

[0131] Thus, excessive temperature rise when the weighting jig 42 abuts against the laminate 99 can be prevented. Thus, the metal eutectic layer 20 can be formed at an appropriate heating temperature.

[0132] In addition, when the weighting step is completed, the temperature setting is changed to the third set temperature lower than the second set temperature. Thus, the metal eutectic layer 20 can be formed at an appropriate heating temperature.

[0133] In addition, when the laminate 99 is placed on the heating jig 41 with the base 10 facing down, a weighting jig 42 is arranged above the cover 30 in the laminate 99. In the heating step, the heating jig and the weighting jig generate heat. In the weighting step, the weighting jig abuts against the cover 30 to apply a weight.

[0134] Thus, the metal eutectic layer 20 can be formed by an appropriate method using the bonding device 48, and the base body 10 and the lid body 30 can be bonded.

[0135] On the contrary, when the laminate 99 is placed on the heating jig 41 with the lid body 30 facing downward, a weighting jig 42 is disposed above the base body 10 in the laminate 99. In the heating process, the heating jig and the weighting jig generate heat. In the weighting process, the weighting jig abuts against the base body 10 to apply weighting.

[0136] Embodiment 2

[0137] *** Different Modes of Bonding Layer - 1 ***

[0138] Figure 10 is a main - part cross - sectional view of the base body and the lid body before bonding according to Embodiment 2, corresponding to Figure 4 Corresponding.

[0139] In the above - mentioned embodiment, the case where the second bonding portion 16 is patterned corresponding to the bonding region 20a has been described, but it is not limited thereto, and patterning may not be performed. Hereinafter, the same parts as those in the above - mentioned embodiment are denoted by the same reference numerals, and repeated descriptions are omitted.

[0140] In the present embodiment, a Ge layer is directly formed on the entire surface of the lid body 30, and this Ge layer is used as the bonding layer 26. Specifically, as Figure 10 shown, the portion of the bonding layer 26 that overlaps with the first bonding portion 15 becomes the second bonding portion 16b, and can be bonded to the first bonding portion 15 to form the metal eutectic layer 20. Other structures are the same as those described in Embodiment 1.

[0141] This structure can also provide an inertial sensor 100 with high bonding strength between the base body 10 and the lid body 30 and excellent long - term reliability. Furthermore, since patterning of the second bonding portion is not required, the processing man - hours are reduced, and the manufacturing cost can be lowered.

[0142] Embodiment 3

[0143] *** Different Modes of Bonding Layer - 2 ***

[0144] Figure 11 is a main - part cross - sectional view of the base body and the lid body before bonding according to Embodiment 3, corresponding to Figure 4 Corresponding. Figure 12 is an enlarged view of the periphery of the metal eutectic layer after bonding, corresponding to Figure 3 Corresponding.

[0145] In the above-described embodiment, the case where the second joint portion 16 is directly formed on the lid 30 has been described, but it is not limited thereto, and a barrier layer 27 may be provided on the substrate. In addition, a sealing hole 36 may be provided in the lid 30. Hereinafter, the same reference numerals are assigned to the same parts as those in the above-described embodiment, and redundant descriptions are omitted.

[0146] In the present embodiment, the second joint portion 28 is formed as a double-layer structure. Specifically, the second joint portion 28 is composed of a barrier layer 27 and a second metal layer 16. The barrier layer 27 is composed of a TiN layer, and the second metal layer 16 is composed of a Ge layer. The barrier layer 27 is provided on the silicon substrate constituting the lid 30. The barrier layer 27 may be a material having a melting point higher than the eutectic point of the metal eutectic layer 20, and may be Ti, Mo, W, Co, Pt, Ta, TiN, or an alloy thereof. In a preferred example, after each layer is formed by using DC sputtering, the second joint portion 28 is formed by patterning corresponding to the joint region 20a. In addition, an RF sputtering method may also be used.

[0147] In addition, a sealing hole 36 penetrating the lid 30 is provided in the lid 30. The sealing hole 36 functions to communicate the outside gas with the accommodation space S when the base 10 and the lid 30 are joined. The sealing hole 36 is formed in a recessed portion recessed from the upper surface of the lid 30, and after the base 10 and the lid 30 are joined, for example, the sealing hole 36 can be sealed using solder balls 37. Alternatively, the sealing hole 36 can be directly melted by a laser for sealing. Except for these structures, the structure is the same as that in Embodiment 1.

[0148] By providing the sealing hole 36, it is not necessary to seal the inside of the accommodation space S when forming the metal eutectic layer 20, so the manufacturing efficiency can be improved.

[0149] Figure 12 is a micrograph of the eutectic layer in the metal eutectic layer 20 formed by joining the first joint portion 15 and the second joint portion 28 by the joining method as described above. Figure 6 and obtained by truthfully tracing.

[0150] As Figure 12 shown, in the metal eutectic layer 20, a first region 21 mainly composed of Al as the first metal and a second region 22 mainly composed of Ge as the second metal are formed in an adjacent state. The second region 22 extends widely along the lid 30, but a part of it reaches the boundary between the metal eutectic layer 20 and the base 10. That is, similar to the description in Figure 3 , a joint with high joint strength is achieved through the metal eutectic layer 20.

[0151] Furthermore, by providing the barrier layer 27, the diffusion of Ge into the lid 30 is prevented, and good electrical contact with the silicon constituting the lid 30 is achieved. That is, ohmic contact between the metal eutectic layer 20 and the lid 30 can be realized through the barrier layer 27.

[0152] Embodiment 4

[0153] ***Application to Inertial Measurement Devices***

[0154] Figure 13 is a top view of the inertial sensor according to Embodiment 4, corresponding to Figure 1 Corresponding.

[0155] In the above embodiment, the case where one sensor element 80 is accommodated in the inertial sensor 100 is described, but it is not limited thereto, and a plurality of sensor elements may be accommodated. Hereinafter, the same parts as those in the above embodiment are denoted by the same reference numerals, and repeated descriptions are omitted.

[0156] As Figure 13 shown, the inertial sensor 110 of the present embodiment includes, in addition to the above-described sensor element 80, a sensor element 85 and a sensor element 86.

[0157] The sensor element 85 is a capacitive acceleration sensor that detects changes in electrostatic capacitance of acceleration in the X direction. The sensor element 86 is a capacitive acceleration sensor that detects changes in electrostatic capacitance of acceleration in the Y direction. That is, the inertial sensor 110 is a three-axis acceleration sensor that can detect acceleration in three axes of the XYZ directions.

[0158] The inertial sensor 110, like the inertial sensor 100, has a structure in which the base 10 and the lid 30 are joined in the joining region 20a through the metal eutectic layer 20, and has a storage space S inside. Three sensor elements 80, 85, and 86 are stored in the storage space S in a swingable state. In Figure 13 , the joining region 20a is a four-sided annular region that is one circle smaller than the outer peripheral edge of the lid 30, but is not limited thereto. The joining region 20a only needs to enclose the sensor elements 80, 85, and 86 and be closed, and may be a polygon or an ellipse. However, it is configured to cross the lead wiring (not shown) in a top view.

[0159] Figure 14 is an exploded perspective view of the inertial measurement device. Figure 15 is a perspective view of the substrate.

[0160] In Figure 14 shown, the inertial measurement device 2000 of the present embodiment is equipped with the inertial sensor 110. The inertial measurement device 2000 is a rectangular parallelepiped having a substantially square top view shape.

[0161] The inertial measurement device 2000 is an inertial measurement sensor unit (IMU: Inertial Measurement Unit) that detects the posture and behavior of an object to be installed such as an automobile or a robot. The inertial measurement device 2000 functions as a so-called six-axis motion sensor equipped with a three-axis acceleration sensor and angular velocity sensors around the three axes.

[0162] The inertial measurement device 2000 includes a housing 301, a joining member 310, and a sensor module 325 on which an inertial sensor is mounted.

[0163] The outer shape of the housing 301 is a rectangular parallelepiped with a substantially square shape in plan view, similar to the overall shape of the inertial measurement device 2000. Threaded holes 302 are formed near two vertices in the diagonal direction of the square. Two screws can be passed through the two threaded holes 302 to fix the inertial measurement device 2000 to the mounting surface of an object to be installed such as an automobile.

[0164] In addition, the housing 301 is box-shaped, and the sensor module 325 is housed inside it. Specifically, a structure is adopted in which the sensor module 325 is inserted into the housing 301 with the joining member 310 interposed therebetween.

[0165] The sensor module 325 includes an inner housing 320 and a substrate 315.

[0166] The inner housing 320 is a component that supports the substrate 315, and the substrate 315 is joined to the lower surface of the inner housing 320 by an adhesive.

[0167] In addition, the inner housing 320 is shaped to be housed inside the housing 301. A recess 331 for preventing contact with the substrate 315 and an opening 321 for exposing a connector 316 described later are formed in the inner housing 320. The inner housing 320 is joined to the housing 301 by the joining member 310.

[0168] Next, the substrate 315 on which the inertial sensor 110 is mounted will be described.

[0169] As Figure 15 shown, an inertial sensor 110, a connector 316, an angular velocity sensor 317z for detecting the angular velocity around the Z axis, etc. are mounted on the upper surface of the substrate 315, i.e., the surface on the inner housing 320 side. An angular velocity sensor 317x for detecting the angular velocity around the X axis and an angular velocity sensor 317y for detecting the angular velocity around the Y axis are mounted on the side surface of the substrate 315. In addition, an inertial sensor 100 may be mounted instead of the inertial sensor 110.

[0170] In addition, a control IC 319 serving as a control unit is mounted on the lower surface of the substrate 315, i.e., the surface on the housing 301 side. The control IC 319 is an MCU (Micro Controller Unit), and is built-in with a storage unit including a non-volatile memory, an A / D converter, etc., and controls each part of the inertial measurement device 2000. A program that specifies the sequence and content for detecting acceleration and angular velocity, a program that digitizes the detection data and assembles it into packet data, attached data, etc. are stored in the storage unit. In addition, a plurality of electronic components are mounted on the substrate 315 in addition to this.

[0171] According to such an inertial measurement device 2000, since the inertial sensor 110 is used, it is possible to provide an inertial measurement device 2000 with excellent long-term reliability that enjoys the effects of the above-described embodiment.

Claims

1. An inertial sensor, which is an electrostatic capacitance change type inertial sensor, having: A substrate; A cover; A functional element disposed between the substrate and the cover; and A metal eutectic layer that joins the substrate and the cover around the functional element, The metal eutectic layer has a plurality of first regions mainly composed of a first metal and having a face-centered cubic lattice structure and second regions mainly composed of a second metal and having a diamond structure, and the first regions and the second regions are adjacent to each other.

2. The inertial sensor according to claim 1, wherein The second region reaches the boundary between the metal eutectic layer and the substrate.

3. The inertial sensor according to claim 2, wherein The second region extends from the cover to the substrate.

4. The inertial sensor according to claim 3, wherein Regarding the portion extending from the cover to the substrate, the second region is more than the first region.

5. The inertial sensor according to claim 3, wherein The contact area between the first region and the second region is larger than the area of the bonding region where the substrate and the cover are bonded through the metal eutectic layer.

6. The inertial sensor according to claim 2, wherein The cover is electrically connected to the power supply wiring of the substrate via the metal eutectic layer.

7. The inertial sensor according to claim 2, wherein The first metal is Al and the second metal is Ge.

8. An electronic component, having: A substrate; A cover; A functional element disposed between the substrate and the cover; and A metal eutectic layer that joins the substrate and the cover around the functional element, The metal eutectic layer has a plurality of first regions mainly composed of a first metal and having a face-centered cubic lattice structure and second regions mainly composed of a second metal and having a diamond structure, and the first regions and the second regions are adjacent to each other.

9. The electronic component according to claim 8, wherein The second region reaches the boundary between the metal eutectic layer and the substrate.

10. The electronic component according to claim 9, wherein The second region extends from the cover to the substrate.

11. The electronic component according to claim 10, wherein Regarding the portion extending from the cover to the substrate, the second region is more than the first region.

12. The electronic component according to claim 10, wherein The contact area between the first region and the second region is larger than the area of the bonding region where the substrate and the cover are bonded through the metal eutectic layer.

13. The electronic component according to claim 9, wherein The cover is electrically connected to the power supply wiring of the substrate via the metal eutectic layer.

14. The electronic component according to claim 9, wherein The first metal is Al and the second metal is Ge.

15. A manufacturing method of an inertial sensor, which is a manufacturing method of joining a substrate provided with a functional element and a cover covering the functional element in a bonding region surrounding the functional element, The manufacturing method includes the following steps: A first joint part mainly composed of a first metal is formed in the joint area in the base body; A second joint part mainly composed of a second metal is formed in the joint area in the cover body; Alignment is performed in such a manner that the first joint part overlaps with the second joint part, and the base body and the cover body are overlapped to form a laminate; A heating step of heating the laminate; and A weighting step of applying a weight to the laminate.

16. The method for manufacturing an inertial sensor according to claim 15, wherein, In the heating step, heating is started at a first set temperature, After the temperature of the laminate is stabilized, after changing the heating setting to a second set temperature lower than the first set temperature, the weighting step is performed.

17. The method for manufacturing an inertial sensor according to claim 16, wherein, When the weighting step is completed, the heating setting is changed to a third set temperature lower than the second set temperature.

18. The method for manufacturing an inertial sensor according to claim 15, wherein, The laminate is placed on a heating jig with the base body facing downward, A weighting jig is disposed above the cover body in the laminate, In the heating step, the heating jig and the weighting jig generate heat, In the weighting step, the weighting jig abuts against the cover body to apply a weight.

19. The method for manufacturing an inertial sensor according to claim 15, wherein, The laminate is placed on a heating jig with the cover body facing downward, A weighting jig is disposed above the base body in the laminate, In the heating step, the heating jig and the weighting jig generate heat, In the weighting step, the weighting jig abuts against the base body to apply a weight.

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