Transducer

Abstract

To provide a highly reliable transducer that can be reliably bonded within a bonding region. [Solution] The transducer 1 includes a first semiconductor substrate 22 on which a functional element 2 is provided, a second semiconductor substrate 23 that houses the functional element 2 together with the first semiconductor substrate 22, a first insulating layer 34 provided on the second semiconductor substrate 23, a second insulating layer 32 provided on the first semiconductor substrate 22, and a eutectic reaction layer 24 that bonds the first semiconductor substrate 22 and the second semiconductor substrate 23 in a bonding region 35, and at least one of the first insulating layer 34 and the second insulating layer 32 has recesses 31, 33 provided in an area wider than the bonding region 35 in a planar view.

Description

[Technical Field]

[0001] The present invention relates to a transducer. [Background technology]

[0002] Conventionally, a sensor device has been known that includes a base body having a cavity, a sensor element suspended within the cavity, and a lid body that seals the cavity. The base body and the lid body are bonded together via a bonding material. The bonding material is required to have high bonding strength and high long-term sealing reliability.

[0003] For example, Patent Document 1 discloses an inertial sensor that uses an AlGe eutectic as a bonding material. According to this document, the concentration of Ge in the AlGe eutectic is either uniform or a function of the distance from the lid or base. In particular, it is disclosed that the concentration of Ge becomes uniform when a long-term heat treatment is performed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2010-0059835 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology of Patent Document 1, there is a risk that the AlGe eutectic bonding material may spread beyond the bonding area or may scatter due to the heat treatment that is performed when forming the bonding material. If the AlGe eutectic scatters, there is a risk that the inertial sensor may malfunction. Since the inertial sensor is an example of a transducer, there has been a demand for a highly reliable transducer that can be reliably bonded within the bonding area. [Means for solving the problem]

[0006] The transducer includes a first semiconductor substrate on which a functional element is provided, a second semiconductor substrate that houses the functional element together with the first semiconductor substrate, a first insulating layer provided on the second semiconductor substrate, a second insulating layer provided on the first semiconductor substrate, and a eutectic reaction layer that bonds the first semiconductor substrate and the second semiconductor substrate in a bonding region, and at least one of the first insulating layer and the second insulating layer has a recess that is provided over a range wider than the bonding region in a planar view. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing a schematic structure of a transducer according to a first embodiment. [Figure 2] 2 is a plan view showing a schematic structure in which a second semiconductor substrate serving as a lid in FIG. 1 has been removed. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIGS. 1 and 2. [Figure 4] FIG. 3 is a cross-sectional view taken along line BB in FIGS. 1 and 2. [Figure 5] FIG. 5 is a cross-sectional view showing the structure in FIG. 4 before bonding. [Figure 6] FIG. 3 is a cross-sectional view taken along line CC in FIGS. 1 and 2. [Figure 7] 3 is a plan view showing a schematic structure of a Y-axis sensor element 21y which is the functional element 2 shown in FIG. 2. [Figure 8] 3 is a plan view showing a schematic structure of a Z-axis sensor element 21z which is the functional element 2 shown in FIG. 2. [Figure 9] FIG. 10 is a plan view showing a schematic structure of a transducer according to a second embodiment. [Figure 10] FIG. 10 is a cross-sectional view taken along line DD in FIG. 9. [Figure 11] FIG. 11 is a cross-sectional view showing the structure in FIG. 10 before bonding. [Figure 12] FIG. 10 is a plan view showing a schematic structure of a transducer according to a third embodiment. [Figure 13] FIG. 13 is a cross-sectional view taken along line EE in FIG. [Figure 14]FIG. 10 is a plan view showing a schematic structure of a transducer according to a fourth embodiment. [Figure 15] 15 is a plan view showing a schematic structure in which a second semiconductor substrate serving as a lid in FIG. 14 has been removed. [Figure 16] 16 is a cross-sectional view taken along line FF in FIGS. 14 and 15. FIG. [Figure 17] 16 is a cross-sectional view taken along line GG in FIGS. 14 and 15. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] 1. First embodiment First, the transducer 1 according to the first embodiment will be described with reference to FIGS. 1 to 6, taking as an example a three-axis acceleration sensor having sensor elements that detect acceleration in the X-axis, Y-axis, and Z-axis directions as the functional element 2. 2, the second semiconductor substrate 23, which serves as a lid, is removed for the convenience of explaining the internal configuration of the transducer 1. Also, in FIG. 2, the wiring that electrically connects the tip of the wiring 30 extending from the connection terminal 29 in the X direction to the movable electrode and fixed electrode of each functional element 2 is not shown.

[0009] For ease of explanation, each figure illustrates three mutually orthogonal axes: the X-axis, the Y-axis, and the Z-axis. The direction along the X-axis is referred to as the "X-direction," the direction along the Y-axis as the "Y-direction," and the direction along the Z-axis as the "Z-direction." The tip of the arrow in each axial direction is referred to as the "plus side," the base end as the "minus side," the plus side of the Z direction as the "upper," and the minus side of the Z direction as the "lower." The Z-direction is vertical, and the XY plane is horizontal.

[0010] Generally, a transducer refers to a converter that converts one physical quantity into another physical quantity, and includes transducers that use electromechanical conversion, transducers that use acoustoelectric conversion, transducers that use photoelectric conversion, etc. The transducer according to one embodiment of the present application may be any transducer in which a base and a lid are joined by a eutectic reaction layer, and may be an inertial sensor that converts acceleration or angular velocity into an electric signal, a vibrator (timing device) in which mechanical vibration is excited by an electric signal, an ultrasonic sensor that converts an ultrasonic signal into an electric signal, an RF filter that utilizes the electromechanical coupling coefficient of a piezoelectric material, a piezoelectric mirror, a piezoelectric actuator, a pressure sensor, etc. In this embodiment, a three-axis acceleration sensor, which is one type of inertial sensor, will be used as an example of a transducer. In an acceleration sensor in which a MEMS device element formed in a substrate is sealed with a lid, when acceleration is applied as an external force, an inertial force acts within the MEMS device element, causing a change in the capacitance value within the element. This change in capacitance is converted into an electrical signal using a differential detection circuit or the like and extracted as a sensor signal. In this embodiment, the functional element 2 is three sensor elements that constitute a three-axis acceleration sensor, but it may also be a sensor element that constitutes a one-axis acceleration sensor, another sensor element, a vibration element that constitutes a vibrator, or a piezoelectric mirror element that constitutes a piezoelectric mirror.

[0011] 1 to 6 can be used as a triaxial acceleration sensor that can independently detect acceleration in three directions. As shown in Figures 1, 2, 3, 4, and 6, such a transducer 1 includes a first semiconductor substrate 22 on which a functional element 2 is provided, a second semiconductor substrate 23 that houses the functional element 2 together with the first semiconductor substrate 22, a first insulating layer 34 provided on the second semiconductor substrate 23, a second insulating layer 32 provided on the first semiconductor substrate 22, and a eutectic reaction layer 24 that bonds the first semiconductor substrate 22 and the second semiconductor substrate 23 in a bonding region 35.

[0012] 1, 2, and 3, the first semiconductor substrate 22 corresponds to a base, and has a recess 26 recessed from its top surface toward the opposite side to the second semiconductor substrate 23, and has a plurality of support portions 11x, 11y, 11z, and 111z protruding upward from an inner bottom surface 27 of the recess 26. Sensor elements 21x, 21y, 21z, and 121z, which are functional elements 2 and detect acceleration in the X-axis, Y-axis, and Z-axis directions, are fixed to the top surfaces of the support portions 11x, 11y, 11z, and 111z so as to fit inside the recess 26 in a plan view. In this embodiment, the sensor elements 21z and 121z that detect acceleration in the two Z-axis directions are provided, thereby improving the detection accuracy of acceleration in the Z-axis direction.

[0013] X-axis sensor element 21x, which detects acceleration in the X-axis direction, has a fixed portion 22x, which is fixed to the upper surface of support portion 11x. Y-axis sensor element 21y, which detects acceleration in the Y-axis direction, has a fixed portion 22y, which is fixed to the upper surface of support portion 11y. Z-axis sensor element 21z, which detects acceleration in the Z-axis direction, has a fixed portion 22z, which is fixed to the upper surface of support portion 11z. Z-axis sensor element 121z, which detects acceleration in the Z-axis direction, has a fixed portion 122z, which is fixed to the upper surface of support portion 111z.

[0014] 4 and 6, a second insulating layer 32 is provided on the first semiconductor substrate 22, and the second insulating layer 32 is provided with a recess 31 that surrounds the recess 26 in a plan view and is recessed from the top surface toward the opposite side to the second semiconductor substrate 23. An insulating layer 20 is disposed on the first semiconductor substrate 22 to prevent electrical conduction between the wiring 30 and the first semiconductor substrate 22.

[0015] Furthermore, a plurality of connection terminals 29 are provided on the first semiconductor substrate 22 along the Y direction at an end on the negative side in the X direction at positions that do not overlap with the second semiconductor substrate 23 in a plan view. Wiring 30 extending in the X direction is provided from each connection terminal 29. Note that the second insulating layer 32 is not formed on the connection terminals 29 and wiring 30 that are arranged at positions that do not overlap with the second semiconductor substrate 23 in a plan view.

[0016] The second semiconductor substrate 23 corresponds to a lid body, and as shown in Figures 1 and 3, has a recess 28 recessed from the underside on the side opposite to the first semiconductor substrate 22, and together with the recess 26 of the first semiconductor substrate 22, it accommodates the functional element 2.

[0017] 4 and 6, a first insulating layer 34 is provided on the lower surface of the second semiconductor substrate 23, and the first insulating layer 34 is provided with a recess 33 that surrounds the recess 28 in a plan view and is recessed from the lower surface toward the opposite side to the first semiconductor substrate 22. The recess 33 provided in the first insulating layer 34 is disposed at a position that overlaps the recess 31 provided in the second insulating layer 32 in a plan view.

[0018] The first semiconductor substrate 22 and the second semiconductor substrate 23 are bonded by the eutectic reaction layer 24 in a bonding region 35 between a recess 31 provided in the second insulating layer 32 of the first semiconductor substrate 22 and a recess 33 provided in the first insulating layer 34 of the second semiconductor substrate 23. The recess 31 of the second insulating layer 32 and the recess 33 of the first insulating layer 34 have a larger area than the bonding region 35 in a planar view. That is, the length in the X direction of the eutectic reaction layer 24 that forms the bonding region 35 is shorter than the lengths in the X direction of the recess 31 and the recess 33, and the length in the Y direction of the eutectic reaction layer 24 that forms the bonding region 35 is shorter than the lengths in the Y direction of the recess 31 and the recess 33. This prevents the bonding region 35 of the eutectic reaction layer 24 that serves as the bonding material from protruding from the recess 31 and the recess 33 and prevents the eutectic reaction layer 24 that serves as the bonding material from scattering.

[0019] In this embodiment, both the first insulating layer 34 and the second insulating layer 32 have recesses 31, 33 that are wider than the bonding region 35 in a planar view, but this is not limited to this, and recesses 31, 33 that are wider than the bonding region 35 in a planar view may be provided in either the first insulating layer 34 or the second insulating layer 32.

[0020] Fig. 5 is a cross-sectional view of a main portion of the first semiconductor substrate 22 and the second semiconductor substrate 23 before bonding, and corresponds to Fig. 4. Before bonding, as shown in Fig. 5, a first metal layer 39 is provided in the recess 33 of the first insulating layer 34, and a second metal layer 38 is provided in the recess 31 of the second insulating layer 32. The first metal layer 39 is a Ge layer. The second metal layer 38 is an AlCu layer. The Cu content of the AlCu layer is low and is incorporated to prevent electromigration. Therefore, the main component of the second metal layer 38 is Al.

[0021] The first metal layer 39 and the second metal layer 38 are bonded by a heating process and a weighting process. Specifically, the stacked body of the first semiconductor substrate 22 and the second semiconductor substrate 23 is heated to a temperature equal to or higher than the eutectic temperature of the first metal layer 39 and the second metal layer 38, and weight is applied in the heated state to form a eutectic bond. The eutectic temperature of AlGe is approximately 420°C. In a preferred example, the stacked body is placed on a stage of a heating jig with the first semiconductor substrate 22 facing downward. Once the stacked body reaches a predetermined temperature, a load is applied from the second semiconductor substrate 23 side using a weighting jig for a predetermined period of time. The weighting jig is also heated during this process. A eutectic generally refers to an alloy formed by solidifying a mixture of two or more metals from a liquid phase.

[0022] Next, the principle of detecting acceleration by the Y-axis sensor element 21y, the X-axis sensor element 21x, and the Z-axis sensor elements 21z and 121z, which are the functional element 2, will be described with reference to FIGS.

[0023] 7, the Y-axis sensor element 21y has three fixed portions 22y aligned in the X direction and two connecting portions 61 aligned in the Y direction, with the three fixed portions 22y arranged between the two connecting portions 61 and the central fixed portion 22y connected to the connecting portion 61. The distance between the connecting portion 61 located on the positive side of the Y direction and the fixed portion 22y is longer than the distance between the connecting portion 61 located on the negative side of the Y direction and the fixed portion 22y.

[0024] The two connecting portions 61 are connected to a movable portion 62 that surrounds the two connecting portions 61 and the three fixed portions 22y on the side opposite to the fixed portion 22y. The movable portion 62 has a plurality of movable electrodes 63 that extend to the positive and negative sides in the X direction between the connecting portion 61 located on the positive side in the Y direction and the fixed portion 22y. Note that the connecting portion 61 is elastically deformable in the Y direction like a spring, and therefore the movable portion 62 is displaceable in the Y direction.

[0025] The two fixed portions 22y located on the positive and negative sides in the X direction of the central fixed portion 22y each have a fixed beam 64 extending diagonally in the Y direction, and a plurality of fixed electrodes 65 extending respectively to the positive and negative sides in the X direction from the fixed beam 64. The plurality of fixed electrodes 65 are arranged on the positive or negative sides in the Y direction of the movable electrode 63, and are arranged in a comb-like shape that meshes with the corresponding movable electrode 63 at intervals.

[0026] When acceleration in the Y direction is applied to such Y-axis sensor element 21y, movable part 62 is displaced in the Y direction based on the magnitude of the acceleration. As the displacement occurs, the magnitude of the capacitance between movable electrode 63 and fixed electrode 65 changes, and the acceleration can be determined based on the change in the capacitance.

[0027] The X-axis sensor element 21x is an element that detects acceleration in the X direction. The X-axis sensor element 21x has the same configuration as the Y-axis sensor element 21y, except that the X-axis sensor element 21x is arranged rotated by 90 degrees in a plan view relative to the Y-axis sensor element 21y.

[0028] The connecting portion 61 connected to the fixed portion 22x is elastically deformable in the X direction like a spring, and therefore the movable portion 62 is displaceable in the X direction, making it possible to detect acceleration in the X direction.

[0029] 8, Z-axis sensor element 21z has fixed part 22z, movable part 72, and a pair of support beams 71 that connect movable part 72 to fixed part 22z so that it can swing, and movable part 72 swings in a seesaw manner relative to fixed part 22z around support beam 71 as axis J1. Such Z-axis sensor element 21z is formed from a silicon substrate doped with impurities such as phosphorus or boron.

[0030] The fixed portion 22z is anodically bonded to the upper surface of the support portion 11z, which protrudes upward from the inner bottom surface 27 of the recess 26 of the first semiconductor substrate 22. Movable portions 72 are provided on the positive and negative Y-direction sides of the fixed portion 22z. The movable portion 72 has a first movable electrode 73 located on the positive Y-direction side of the axis J1, and a second movable electrode 74 and a third movable electrode 75 located on the negative Y-direction side of the axis J1. The first movable electrode 73 and the second movable electrode 74 are designed to have different rotational moments when acceleration in the Z direction is applied, so that a predetermined tilt occurs in the movable portion 72 in response to the acceleration. As a result, when acceleration in the Z direction occurs, the movable portion 72 performs a seesaw swing around the axis J1.

[0031] Furthermore, a first detection electrode 76 is arranged at a position facing the first movable electrode 73 on the inner bottom surface 27 of the recess 26, a second detection electrode 77 is arranged at a position facing the second movable electrode 74, and a dummy electrode 78 is arranged at a position facing the third movable electrode 75. Therefore, a capacitance is formed between the first movable electrode 73 and the first detection electrode 76, and a capacitance is formed between the second movable electrode 74 and the second detection electrode 77. The dummy electrode 78 is provided to suppress electrostatic charge generation on the inner bottom surface 27 of the recess 26.

[0032] When acceleration in the Z direction is applied to such Z-axis sensor element 21z, the movable part 72 undergoes a seesaw oscillation around axis J1. This seesaw oscillation of movable part 72 changes the distance between first movable electrode 73 and first detection electrode 76 and the distance between second movable electrode 74 and second detection electrode 77, and the capacitance therebetween changes accordingly, so that the acceleration can be determined based on the change in capacitance.

[0033] The Z-axis sensor element 121z is an element that detects acceleration in the Z direction. The Z-axis sensor element 121z has the same configuration as the Z-axis sensor element 21z, except that the Z-axis sensor element 121z is arranged rotated 180 degrees in a plan view relative to the Z-axis sensor element 21z.

[0034] In this embodiment, a transducer 1 having a configuration in which a functional element 2 is bonded onto a first semiconductor substrate 22 has been described as an example, but this is not limited to this, and the first semiconductor substrate 22 may be an SOI (Silicon On Insulator) substrate with the functional element 2 integrated therein.

[0035] As described above, in the transducer 1 of this embodiment, the recess 31 provided in the second insulating layer 32 and the recess 33 provided in the first insulating layer 34 have a larger area in plan view than the bonding region 35 of the eutectic reaction layer 24. This makes it possible to prevent the bonding region 35 of the eutectic reaction layer 24, which serves as the bonding material, from protruding from the recess 31 and the recess 33, and to prevent the eutectic reaction layer 24, which serves as the bonding material, from scattering.

[0036] 2. Second embodiment Next, a transducer 1a according to a second embodiment will be described with reference to FIGS.

[0037] The transducer 1a of this embodiment is similar to the transducer 1 of the first embodiment except that the structures of the first insulating layer 34a and the second insulating layer 32a are different from those of the transducer 1 of the first embodiment. Note that the following description will focus on the differences from the first embodiment described above, and a description of similar points will be omitted.

[0038] 9 and 10, the transducer 1a includes a first semiconductor substrate 22a on which a functional element 2 is provided, a second semiconductor substrate 23a that houses the functional element 2 together with the first semiconductor substrate 22a, a first insulating layer 34a provided on the second semiconductor substrate 23a, a second insulating layer 32a provided on the first semiconductor substrate 22a, and a eutectic reaction layer 24 that bonds the first semiconductor substrate 22a and the second semiconductor substrate 23a in a bonding region 35. An insulating layer 20 that prevents conduction between the wiring 30 and the first semiconductor substrate 22a is disposed on the first semiconductor substrate 22a.

[0039] The first insulating layer 34a has a first through-hole 37 in a region overlapping with the eutectic reaction layer 24 and the recess 33 in a plan view, and the second semiconductor substrate 23a and the eutectic reaction layer 24 are in contact with each other via the first through-hole 37. Therefore, the second semiconductor substrate 23a and the eutectic reaction layer 24 can be at the same potential.

[0040] The second insulating layer 32a has a second through hole 36 at a position overlapping the first through hole 37 in a region overlapping with the eutectic reaction layer 24 and the recess 31 in a plan view, and the wiring 30 provided between the first semiconductor substrate 22 and the second insulating layer 32a and the eutectic reaction layer 24 are in contact with each other via the second through hole 36. Therefore, the wiring 30 and the eutectic reaction layer 24 can be at the same potential.

[0041] Before bonding, as shown in FIG. 11, the second semiconductor substrate 23a and the first metal layer 39 are in contact with each other through a first through hole 37 provided in the first insulating layer 34a, and the wiring 30 and the second metal layer 38 are in contact with each other through a second through hole 36 provided in the second insulating layer 32a.

[0042] With this configuration, the eutectic reaction layer 24, the second semiconductor substrate 23a, and the wiring 30 can be at the same potential, and the same effect as that of the transducer 1 of the first embodiment can be obtained.

[0043] 3. Third embodiment Next, a transducer 1b according to a third embodiment will be described with reference to FIGS.

[0044] The transducer 1b of this embodiment is similar to the transducer 1 of the first embodiment except that the structure of the recess 33b in the first insulating layer 34b is different from that of the transducer 1 of the first embodiment. Note that the following description will focus on the differences from the first embodiment described above, and a description of similar points will be omitted.

[0045] 12 and 13, the transducer 1b includes a first semiconductor substrate 22 on which a functional element 2 is provided, a second semiconductor substrate 23b that houses the functional element 2 together with the first semiconductor substrate 22, a first insulating layer 34b provided on the second semiconductor substrate 23b, a second insulating layer 32 provided on the first semiconductor substrate 22, and a eutectic reaction layer 24 that bonds the first semiconductor substrate 22 and the second semiconductor substrate 23 in a bonding region 35. An insulating layer 20 that prevents conduction between the wiring 30 and the first semiconductor substrate 22 is disposed on the first semiconductor substrate 22.

[0046] The second semiconductor substrate 23b has a recess 28b provided with a protrusion 41 extending from the Y-direction end toward the positive side in the Y-direction. The recess 33b of the first insulating layer 34b provided on the lower surface of the second semiconductor substrate 23b has a third through-hole 40 in the protruding portion 41, and the second semiconductor substrate 23b and the first metal layer 39 that does not form eutectic are in contact with each other via the third through-hole 40. Therefore, the second semiconductor substrate 23b and the eutectic reaction layer 24 are in contact with each other via the first metal layer 39, and the second semiconductor substrate 23b and the eutectic reaction layer 24 can be at the same potential.

[0047] With this configuration, the eutectic reaction layer 24 and the second semiconductor substrate 23b can be at the same potential, and the same effect as that of the transducer 1 of the first embodiment can be obtained.

[0048] 4. Fourth embodiment Next, a transducer 1c according to a fourth embodiment will be described with reference to FIGS.

[0049] The transducer 1c of this embodiment is similar to the transducer 1 of the first embodiment except that the structure of the functional element 2c is different from that of the transducer 1 of the first embodiment. Note that the following description will focus on the differences from the first embodiment described above, and a description of similar points will be omitted.

[0050] As shown in Figures 14 to 17, the transducer 1c is a vibrator with a three-legged structure, and includes a first semiconductor substrate 22c on which a functional element 2c is provided, a second semiconductor substrate 23c that houses the functional element 2c together with the first semiconductor substrate 22c, a first insulating layer 34 provided on the second semiconductor substrate 23c, a second insulating layer 32 provided on the first semiconductor substrate 22c, and a eutectic reaction layer 24 that bonds the first semiconductor substrate 22 and the second semiconductor substrate 23 in a bonding region 35.

[0051] 15 and 16, the first semiconductor substrate 22 is provided with a recess 26 recessed from the top surface toward the opposite side to the second semiconductor substrate 23, and has a support portion 11c protruding upward from an inner bottom surface 27 of the recess 26. A vibration element having three vibration arms 43, which is a functional element 2c, is fixed to the top surface of the support portion 11c so as to fit inside the recess 26 in a plan view.

[0052] The functional element 2c has a fixed portion 42 and three vibrating arms 43 extending in a predetermined direction from the fixed portion 42, and the fixed portion 42 is fixed to the upper surface of the support portion 11c.

[0053] 17, a second insulating layer 32 is provided on the first semiconductor substrate 22c, and the second insulating layer 32 is provided with a recess 31 that surrounds the recess 26 in a plan view and is recessed from the top surface toward the opposite side to the second semiconductor substrate 23. An insulating layer 20 is disposed on the first semiconductor substrate 22c to prevent electrical conduction between wiring (not shown) and the first semiconductor substrate 22c.

[0054] As shown in FIG. 17, the second semiconductor substrate 23c is provided with a recess 28 recessed from the lower surface toward the opposite side to the first semiconductor substrate 22c, and accommodates the functional element 2c together with the recess 26 of the first semiconductor substrate 22c.

[0055] A first insulating layer 34 is provided on the lower surface of the second semiconductor substrate 23c, and the first insulating layer 34 is provided with a recess 33 that surrounds the recess 28 in a plan view and is recessed from the lower surface toward the opposite side to the first semiconductor substrate 22c side. The recess 33 provided in the first insulating layer 34 is disposed at a position that overlaps with the recess 31 provided in the second insulating layer 32 in a plan view.

[0056] The first semiconductor substrate 22c and the second semiconductor substrate 23c are bonded by the eutectic reaction layer 24 in a bonding region 35 between a recess 31 provided in the second insulating layer 32 of the first semiconductor substrate 22c and a recess 33 provided in the first insulating layer 34 of the second semiconductor substrate 23c. The recess 31 of the second insulating layer 32 and the recess 33 of the first insulating layer 34 have a wider area than the bonding region 35 in a plan view.

[0057] With this configuration, it is possible to obtain the same effects as the transducer 1 of the first embodiment. [Explanation of symbols]

[0058] 1, 1a, 1b, 1c... transducer, 2... functional element, 20... insulating layer, 22... first semiconductor substrate, 23... second semiconductor substrate, 24... eutectic reaction layer, 26... recess, 27... inner bottom surface, 28... recess, 29... connection terminal, 30... wiring, 31... recess, 32... second insulating layer, 33... recess, 34... first insulating layer, 35... bonding region, 36... second through hole, 37... first through hole, 38... second metal layer, 39... first metal layer.

Claims

1. a first semiconductor substrate provided with a functional element; a second semiconductor substrate that accommodates the functional element together with the first semiconductor substrate; a first insulating layer provided on the second semiconductor substrate; a second insulating layer provided on the first semiconductor substrate; a eutectic reaction layer that bonds the first semiconductor substrate and the second semiconductor substrate in a bonding region; At least one of the first insulating layer and the second insulating layer has a recess provided in a range wider than the bonding region in a plan view. Transducer.

2. the first insulating layer has a first through hole in a region overlapping with the eutectic reaction layer and the recess in a plan view; the second semiconductor substrate and the eutectic reaction layer are in contact with each other through the first through hole; The transducer of claim 1 .

3. further comprising wiring provided between the first semiconductor substrate and the second insulating layer; the second insulating layer has a second through hole in a region overlapping with the eutectic reaction layer and the recess in a plan view; the wiring and the eutectic reaction layer are in contact with each other through the second through hole; The transducer of claim 2 .

4. the first through hole and the second through hole overlap in a plan view; The transducer of claim 3 .

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