Compound sensor and manufacturing method

Abstract

To suppress deterioration in detection accuracy while collecting three detection portions in one package.SOLUTION: A compound sensor 1 comprises a package 2, a first acceleration detection portion 51, a second acceleration detection portion 52, and an angular velocity detection portion 53. The first acceleration detection portion 51 is disposed in a first cavity C1. The second acceleration detection portion 52 is disposed in a second cavity C2. The angular velocity detection portion 53 is disposed in a third cavity C3. An inner pressure of the first cavity C1 is higher than an inner pressure of the second cavity C2. An inner pressure of the third cavity C3 is lower than the inner pressure of the second cavity C2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates generally to a composite sensor and a manufacturing method, and more particularly to a composite sensor having three detection units and a manufacturing method for the composite sensor. [Background technology]

[0002] The composite sensor described in Patent Document 1 is manufactured based on a sensor wafer and a cap wafer. The sensor wafer has an acceleration sensor and an angular velocity sensor. The acceleration sensor is bonded and sealed in an atmospheric pressure atmosphere by bonding the sensor wafer and the cap wafer in an atmospheric pressure atmosphere. The angular velocity sensor is bonded and sealed in a vacuum atmosphere by deformation of the bumps due to heating and loading of the sensor wafer and the cap wafer in a vacuum atmosphere. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-242371 A Summary of the Invention [Problem to be solved by the invention]

[0004] The composite sensor described in Patent Document 1 has a structure in which an acceleration sensor (acceleration detection portion) and an angular velocity sensor (angular velocity detection portion) are housed in separate packages.

[0005] An object of the present disclosure is to provide a composite sensor and a manufacturing method thereof that can consolidate three detection units into one package while suppressing a decrease in detection accuracy. [Means for solving the problem]

[0006] A composite sensor according to an aspect of the present disclosure includes a package, a first acceleration detection unit, a second acceleration detection unit, and an angular velocity detection unit. The package has a first cavity, a second cavity, and a third cavity inside. The first acceleration detection unit is disposed in the first cavity. The second acceleration detection unit is disposed in the second cavity. The angular velocity detection unit is disposed in the third cavity. An upper limit value of acceleration detectable by the first acceleration detection unit is smaller than an upper limit value of acceleration detectable by the second acceleration detection unit. An internal pressure of the first cavity is higher than an internal pressure of the second cavity. An internal pressure of the third cavity is lower than the internal pressure of the second cavity.

[0007] A manufacturing method according to an aspect of the present disclosure is a manufacturing method for a composite sensor including a package including a bottom wall, a side portion, and a cover, and includes the following first to fourth steps. The first step is a step of forming a first acceleration detection unit, a second acceleration detection unit, and an angular velocity detection unit in a first space, a second space, and a third space provided in the side portion, respectively. The second step is a step of attaching the side portion between the bottom wall and the cover, and forming a first cavity including the first space, a second cavity including the second space, and a third cavity including the third space, between the bottom wall and the cover. The third step is a step of forming at least one first through hole and at least one second through hole in the cover, which connect the first cavity and the second cavity to the outside, respectively. The fourth step is performed after the second step. The fourth step is a step of filling each of the at least one first through hole and the at least one second through hole with a getter material that adsorbs gas. An upper limit value of acceleration detectable by the first acceleration detection unit is lower than an upper limit value of acceleration detectable by the second acceleration detection unit. An internal pressure of the first cavity is higher than an internal pressure of the second cavity. An internal pressure of the third cavity is lower than the internal pressure of the second cavity. A sum of the opening areas of the at least one second through hole is larger than a sum of the opening areas of the at least one first through hole.

[0008] A manufacturing method according to another aspect of the present disclosure is a manufacturing method for a composite sensor including a package including a bottom wall, a side portion, and a cover, and includes the following first to third and fifth steps. The first step is a step of forming a first acceleration detection unit, a second acceleration detection unit, and an angular velocity detection unit in a first space, a second space, and a third space provided in the side portion, respectively. The second step is a step of attaching the side portion between the bottom wall and the cover, and forming a first cavity including the first space, a second cavity including the second space, and a third cavity including the third space, between the bottom wall and the cover. The third step is a step of forming at least one first through hole and at least one second through hole in the cover, which connect the first cavity and the second cavity to the outside, respectively. The fifth step is a step of filling each of the at least one first through hole and the at least one second through hole with an outgassing material that generates gas. An upper limit value of acceleration detectable by the first acceleration detection unit is lower than an upper limit value of acceleration detectable by the second acceleration detection unit. An internal pressure of the first cavity is higher than an internal pressure of the second cavity. An internal pressure of the third cavity is lower than the internal pressure of the second cavity. A sum of the opening areas of the at least one first through hole is larger than a sum of the opening areas of the at least one second through hole. Effect of the Invention

[0009] The present disclosure has an advantage in that three detection units can be integrated into one package while suppressing a decrease in detection accuracy. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a side cross-sectional view of the composite sensor according to the first embodiment. [Diagram 2] FIG. 2 is a side cross-sectional view showing a base and a plurality of detection units of the above composite sensor. [Diagram 3] FIG. 3 is a side cross-sectional view showing a manufacturing process of the above composite sensor. [Figure 4] FIG. 4 is a side cross-sectional view showing a manufacturing process of the above composite sensor. [Diagram 5] 5A and 5B are plan and side sectional views showing the manufacturing process of the above composite sensor. [Figure 6] FIG. 6 is a side cross-sectional view showing a manufacturing process of the above composite sensor. [Figure 7] FIG. 7 is a flowchart showing a method for manufacturing the above composite sensor. [Figure 8] FIG. 8 is an enlarged side cross-sectional view of the above composite sensor. [Figure 9] FIG. 9 is an explanatory diagram relating to a manufacturing process of the above composite sensor. [Figure 10] FIG. 10 is a plan view of a main part of a composite sensor according to a first modification of the first embodiment. [Figure 11] FIG. 11 is a side cross-sectional view of the composite sensor according to the second embodiment. [Figure 12] FIG. 12 is a side cross-sectional view of the composite sensor according to the third embodiment. [Figure 13] FIG. 13 is a side cross-sectional view of a composite sensor according to a first modification of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In the following embodiments, the composite sensor and manufacturing method of the present disclosure will be described with reference to the drawings. However, the following embodiments are merely a part of the various embodiments of the present disclosure. The following embodiments can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. In addition, the following embodiments may be realized by appropriately combining them, including modified examples. In addition, the figures described in the following embodiments are schematic diagrams, and the ratios of the sizes and thicknesses of the components in the figures do not necessarily reflect the actual dimensional ratios.

[0012] (Embodiment 1) (overview) 1, the composite sensor 1 of this embodiment includes a package 2, a first acceleration detection unit 51, a second acceleration detection unit 52, and an angular velocity detection unit 53. Each of the first acceleration detection unit 51, the second acceleration detection unit 52, and the angular velocity detection unit 53 is an example of a detection unit 5 that is housed in the package 2 and detects a physical quantity. The number of detection units 5 may be four or more, but in this embodiment, the number of detection units 5 is three.

[0013] The package 2 has a first cavity C1 (hollow), a second cavity C2, and a third cavity C3 therein. The first acceleration detection unit 51 is disposed in the first cavity C1. The second acceleration detection unit 52 is disposed in the second cavity C2. The angular velocity detection unit 53 is disposed in the third cavity C3. The upper limit value of acceleration detectable by the first acceleration detection unit 51 is smaller than the upper limit value of acceleration detectable by the second acceleration detection unit 52. The internal pressure of the first cavity C1 is higher than the internal pressure of the second cavity C2. The internal pressure of the third cavity C3 is lower than the internal pressure of the second cavity C2.

[0014] Each acceleration detection unit (the first acceleration detection unit 51 and the second acceleration detection unit 52) ​​has a unique resonance frequency corresponding to the upper limit of the detectable acceleration. Vibration of each acceleration detection unit at the resonance frequency can cause a decrease in detection accuracy. In order to suppress vibration of each acceleration detection unit at the resonance frequency, it is necessary to arrange each acceleration detection unit in an environment with an internal pressure corresponding to the resonance frequency, so that the damping effect of the gas (the effect of suppressing the vibration of the acceleration detection unit) is made to have a magnitude corresponding to the resonance frequency. That is, it is necessary to provide a difference between the damping effect on the first acceleration detection unit 51 and the damping effect on the second acceleration detection unit 52. To achieve this, in the composite sensor 1 of this embodiment, a difference is provided between the internal pressure of the first cavity C1 and the internal pressure of the second cavity C2 as described above. Therefore, in the composite sensor 1 of this embodiment, it is possible to suppress a decrease in the detection accuracy of each acceleration detection unit.

[0015] Furthermore, unless the angular velocity detection unit 53 is placed in a low-pressure environment that can suppress the damping effect of gas (the effect of suppressing vibration of the angular velocity detection unit 53), the characteristics related to the detection accuracy of the angular velocity detection unit 53 may deteriorate. Therefore, as described above, the internal pressure of the third cavity C3 in which the angular velocity detection unit 53 is placed is set lower than the internal pressure of the second cavity C2. This makes it possible to suppress deterioration in the detection accuracy of the angular velocity detection unit 53.

[0016] In this way, according to the composite sensor 1 of this embodiment, the first acceleration detection unit 51, the second acceleration detection unit 52, and the angular velocity detection unit 53 can be integrated into a single package 2 while suppressing a decrease in the detection accuracy of each detection unit 5.

[0017] A desirable ratio between the internal pressure of the first cavity C1 and the internal pressure of the second cavity C2 varies depending on the characteristics of the first acceleration detection portion 51 and the second acceleration detection portion 52. In order to suppress vibration of each acceleration detection portion at a resonant frequency, as an example, the internal pressure of the first cavity C1 is equal to or greater than √5 times the internal pressure of the second cavity C2.

[0018] The upper limit of acceleration detectable by the first acceleration detection unit 51 and the second acceleration detection unit 52 is determined by the structure of each acceleration detection unit, etc. For example, each acceleration detection unit includes a movable part 5a (see FIG. 1) that displaces according to acceleration, and if the acceleration exceeds the upper limit, the movable part 5a collides with other components, making it impossible to detect the acceleration.

[0019] The composite sensor 1 is used, for example, to detect the presence or absence of a collision of an object. In this case, by suppressing a decrease in the detection accuracy of each detection unit 5, the presence or absence of a collision can be detected more accurately.

[0020] In addition, the composite sensor 1 can be used for various purposes. For example, the composite sensor 1 is a sensor mounted on an automobile, and the first acceleration detection unit 51, the second acceleration detection unit 52, and the angular velocity detection unit 53 of the composite sensor 1 are used for different purposes in the automobile. The purposes in the automobile include, for example, detection of the travel distance, detection of the orientation of the vehicle body, and detection of the presence or absence of a collision of an object with the vehicle body.

[0021] (detail) (1) Overall structure As shown in Fig. 1, the composite sensor 1 of this embodiment includes a package 2, a first acceleration detection unit 51, a second acceleration detection unit 52, an angular velocity detection unit 53, a protective film 6, and a plurality of getter materials G1 and G2. Each of the plurality of getter materials G1 and G2 is a member that adsorbs gas. The internal pressure of the first cavity C1 and the internal pressure of the second cavity C2 are adjusted by the plurality of getter materials G1 and G2 adsorbing gas.

[0022] (2) Package The package 2 is formed of, for example, a material including a silicon semiconductor. The package 2 includes a base 3 and a cover 4. In the following, the side on which the cover 4 is located as viewed from the base 3 is defined as the upper side, and the side on which the base 3 is located as viewed from the cover 4 is defined as the lower side. However, these definitions are not intended to limit the direction in which the composite sensor 1 is used.

[0023] 2 shows only the base 3 and the multiple detection units 5 of the composite sensor 1. As shown in FIGS.

[0024] As shown in FIG. 2, the base 3 has a first recess R1, a second recess R2, and a third recess R3. The first recess R1 constitutes a part of the first cavity C1. The second recess R2 constitutes a part of the second cavity C2. The third recess R3 constitutes a part of the third cavity C3. The bottom wall 31 has a bottom surface of each of the first recess R1, the second recess R2, and the third recess R3. The side portion 32 protrudes from the bottom wall 31 so as to constitute at least a part of a side surface of each of the first recess R1, the second recess R2, and the third recess R3. When viewed from above, each of the first recess R1, the second recess R2, and the third recess R3 is surrounded by the side portion 32.

[0025] The base 3 further has a first opening OP1, a second opening OP2, and a third opening OP3. The first opening OP1, the second opening OP2, and the third opening OP3 are provided at the upper ends of the first recess R1, the second recess R2, and the third recess R3, respectively. The first opening OP1 opens the first recess R1 to the outside of the base 3. The second opening OP2 opens the second recess R2 to the outside of the base 3. The third opening OP3 opens the third recess R3 to the outside of the base 3.

[0026] The cover 4 is formed in a plate shape. The cover 4 is fixed to the base 3. The cover 4 covers the first opening OP1, the second opening OP2, and the third opening OP3.

[0027] The cover 4 has a fourth recess R4, a fifth recess R5, and a sixth recess R6. The first recess R1 and the fourth recess R4 are connected to each other, and their bottom surfaces face each other. The second recess R2 and the fifth recess R5 are connected to each other, and their bottom surfaces face each other. The third recess R3 and the sixth recess R6 are connected to each other, and their bottom surfaces face each other.

[0028] The first cavity C1 is a cavity including the first recess R1 and the fourth recess R4. The second cavity C2 is a cavity including the second recess R2 and the fifth recess R5. The third cavity C3 is a cavity including the third recess R3 and the sixth recess R6.

[0029] The cover 4 has one first through hole T1 and two or more second through holes T2.

[0030] The first through hole T1 connects the first cavity C1 to the outside of the cover 4. Specifically, the first through hole T1 penetrates between the bottom surface of the fourth recess R4 and the upper surface of the cover 4 (the surface opposite to the side where the fourth recess R4 is provided). The longitudinal direction of the first through hole T1 is along the up-down direction.

[0031] Each of the two or more second through holes T2 connects the second cavity C2 to the outside of the cover 4. Specifically, each of the two or more second through holes T2 penetrates between the bottom surface of the fifth recess R5 and the upper surface of the cover 4 (the surface opposite to the side where the fifth recess R5 is provided). The longitudinal direction of each of the two or more second through holes T2 is along the up-down direction.

[0032] 5A and 5B show the package 2 before being covered with the protective film 6 in the manufacturing process of the composite sensor 1. As shown in FIG. 5A, a first through hole T1 is formed at a position overlapping with the center of the first cavity C1 when viewed from above. That is, the center of the first cavity C1 and the center of the region in which the first through hole T1 is provided overlap. Also, when viewed from above, the center of the second cavity C2 and the center of the region in which two or more second through holes T2 are provided overlap. When viewed from above, the two or more second through holes T2 are provided in the region overlapping with the second cavity C2. The two or more second through holes T2 are arranged at equal intervals from each other.

[0033] (3) Protective film The upper surface of the package 2 is covered with a protective film 6. In other words, the upper surface of the cover 4 (the surface opposite to the first cavity C1, the second cavity C2, and the third cavity C3) is covered with the protective film 6. The protective film 6 also covers the first through hole T1 and two or more second through holes T2 that the cover 4 has.

[0034] The protective film 6 is, for example, a silicon oxide film or a silicon nitride film, or is formed of a material containing polyimide, such as polyimide-polybenzoxazole (PBO).

[0035] (4) Three detectors The composite sensor 1 includes three detection units 5, namely, a first acceleration detection unit 51, a second acceleration detection unit 52, and an angular velocity detection unit 53. Each of the three detection units 5 includes a movable unit 5a and a plurality of detection elements 5b (two in FIG. 1). The movable unit 5a is displaced in response to the acceleration or angular velocity. The detection elements 5b are disposed around the movable unit 5a. The detection elements 5b input a signal to the movable unit 5a or output a signal from the movable unit 5a.

[0036] When acceleration is applied to each of the first acceleration detection unit 51 and the second acceleration detection unit 52, the movable unit 5a is displaced by the acceleration. A signal according to the amount of displacement is output as an acceleration signal representing the acceleration via the detection element 5b.

[0037] In the angular velocity detection unit 53, when an angular velocity is applied while the movable part 5a is being driven to vibrate, the movable part 5a is displaced by the Coriolis force. A signal according to the amount of displacement is output as an angular velocity signal representing the angular velocity via the detection element 5b.

[0038] (5) Multiple getter materials The composite sensor 1 includes a getter material G1 and two or more getter materials G2 as a plurality of getter materials. The getter material G1 and the two or more getter materials G2 are each a member that adsorbs gas, and are, for example, a zirconium (Zr) alloy or a titanium (Ti) alloy. More specifically, the getter material G1 and the two or more getter materials G2 are, for example, a Zr-V-Fe alloy, a Zr-Al-Ni alloy, a Ti-Zr-V alloy, a Ti-Cr-V alloy, or a Ti-Zr-Cr-V alloy. The gases adsorbed by the getter material G1 and the two or more getter materials G2 are, for example, hydrogen, nitrogen, oxygen, carbon dioxide, carbon monoxide, methane, ammonia, water vapor, hydrogen sulfide, and organic compounds.

[0039] The number of getter materials G1 is the same as the number of first through holes T1, and the number of getter materials G2 is the same as the number of second through holes T2.

[0040] The first through-hole T1 is filled with a getter material G1. The two or more second through-holes T2 are each filled with a getter material G2.

[0041] The first cavity C1 is sealed by a getter material G1. The second cavity C2 is sealed by two or more getter materials G2. The first through hole T1 and the two or more second through holes T2 are respectively filled with the getter material G1 and the two or more getter materials G2, and a protective film 6 is formed on the getter material G1 and the two or more getter materials G2.

[0042] The sum of the opening areas of the two or more second through holes T2 is larger than the opening area of ​​the first through hole T1. More specifically, as shown in Fig. 5A, the opening areas of the first through hole T1 and the two or more second through holes T2 are approximately the same, but the number of the second through holes T2 is greater than the number of the first through holes T1.

[0043] (6) Manufacturing method Next, a method for manufacturing the composite sensor 1 will be described with reference to Fig. 1 and Fig. 3 to Fig. 7. The composite sensor 1 is manufactured using one or more manufacturing devices. Note that the flowchart shown in Fig. 7 merely shows one example of a method for manufacturing the composite sensor 1, and the order of each step included in the manufacturing method may be changed as appropriate, and steps may be added or omitted as appropriate.

[0044] First, the bottom wall 31, the side portion 32 supporting the three detection units 5, and the cover 4P that serves as the base of the cover 4 are individually prepared.

[0045] More specifically, the side portion 32 and the three detection units 5 are formed by processing a material (silicon wafer) that is the base of the side portion 32 (step ST1 in FIG. 7). As shown in FIG. 3, the side portion 32 includes a first space SP1 in which the first acceleration detection unit 51 is disposed, a second space SP2 in which the second acceleration detection unit 52 is disposed, and a third space SP3 in which the angular velocity detection unit 53 is disposed. The side portion 32 is penetrated in the up-down direction by each of the first space SP1, the second space SP2, and the third space SP3.

[0046] The system consisting of the side portion 32 and the three detection portions 5 is formed using microfabrication technology, and is a so-called MEMS (Micro Electro Mechanical Systems).

[0047] Similarly to the cover 4, the cover 4P has a fourth recess R4, a fifth recess R5, and a sixth recess R6. The cover 4P further has a recess T10 which is the base of the first through hole T1, and two or more recesses T20 which are the bases of two or more second through holes T2. The recess T10 is formed on the bottom surface of the fourth recess R4. The recess T20 is formed on the bottom surface of the fifth recess R5.

[0048] 4, in an atmosphere of lower pressure than atmospheric pressure (e.g., vacuum), the cover 4P is joined to the upper surface of the side portion 32 (step ST2), and the bottom wall 31 is joined to the lower surface of the side portion 32 (step ST3). Either the cover 4P or the bottom wall 31 may be joined to the side portion 32 first.

[0049] A first recess R1, a second recess R2, and a third recess R3 are formed by joining the bottom wall 31 to the side portion 32. At this time, a first acceleration detection unit 51, a second acceleration detection unit 52, and an angular velocity detection unit 53 are disposed in the first recess R1, the second recess R2, and the third recess R3, respectively. The first recess R1, the second recess R2, and the third recess R3 include a first space SP1, a second space SP2, and a third space SP3, respectively.

[0050] Furthermore, by joining the bottom wall 31 and the cover 4P to the side portion 32, a first cavity C1, a second cavity C2, and a third cavity C3 are formed between the bottom wall 31 and the cover 4P.

[0051] Next, the cover 4 is formed as shown in FIG. 5B by forming the first through hole T1 and two or more second through holes T2 in the cover 4P (step ST4). More specifically, the upper part of the cover 4P is scraped off to connect the recess T10 and two or more recesses T20 to the space above the cover 4P. The recess T10 and two or more recesses T20 connected to the space above the cover 4P correspond to the first through hole T1 and two or more second through holes T2, respectively. That is, the first through hole T1 and two or more second through holes T2 are formed by scraping off the upper part of the cover 4P.

[0052] Next, the first through hole T1 and the two or more second through holes T2 are filled with getter materials G1 and G2, respectively (step ST5). Here, the getter materials G1 and G2 are made of the same material. When the material of the getter materials G1 and G2 (for example, titanium alloy) is irradiated onto the upper surface of the cover 4 by sputtering, as shown in FIG. 6, the first through hole T1 and the two or more second through holes T2 are filled with the getter materials G1 and G2, respectively, and a getter material G0 is formed in a layer on the upper surface of the cover 4. The getter material G0 is removed (step ST6), and then, as shown in FIG. 1, a protective film 6 is formed (step ST7). For example, magnetron sputtering is suitable for sputtering.

[0053] In the manufacturing process of the composite sensor 1, a wafer including a plurality of composite sensors 1 is manufactured by the above-mentioned steps. After that, the wafer is divided into a plurality of composite sensors 1 by dicing (step ST8). In this way, a plurality of composite sensors 1 are completed.

[0054] In steps ST2 and ST3, the cover 4P and the bottom wall 31 are joined to the side portion 32 in an atmosphere lower than atmospheric pressure, so that the internal pressure of the third cavity C3 sealed by the cover 4P (or the cover 4) becomes the same as the atmospheric pressure.

[0055] When the package 2 is placed under atmospheric pressure with the cover 4 having the first through hole T1 and the two or more second through holes T2, the first cavity C1 and the second cavity C2 take in outside air through the first through hole T1 and the two or more second through holes T2, respectively, and the internal pressure becomes equal to atmospheric pressure. However, in step ST5, the getter materials G1 and G2 are filled, and the getter materials G1 and G2 adsorb gas, so that the internal pressure of the first cavity C1 and the second cavity C2 decreases. The first cavity C1 is exposed to the getter material G1 filled in the first through hole T1, and the second cavity C2 is exposed to two or more getter materials G2 filled in two or more second through holes T2. The sum of the opening areas of the two or more second through holes T2 is greater than the opening area of ​​the first through hole T1. Therefore, the amount of gas adsorbed by the two or more getter materials G2 in the second cavity C2 is greater than the amount of gas adsorbed by the getter material G1 in the first cavity C1. As a result, the internal pressure of the first cavity C1 becomes higher than the internal pressure of the second cavity C2.

[0056] To summarize the above, the manufacturing method of the composite sensor 1 of this embodiment includes the following first to fourth steps. The first step (step ST1) is a step of forming the first acceleration detection unit 51, the second acceleration detection unit 52, and the angular velocity detection unit 53 in the first space SP1, the second space SP2, and the third space SP3 provided in the side portion 32, respectively. The second step (steps ST2 and ST3) is a step of attaching the side portion 32 between the bottom wall 31 and the cover 4, and forming the first cavity C1 including the first space SP1, the second cavity C2 including the second space SP2, and the third cavity C3 including the third space SP3 between the bottom wall 31 and the cover 4. The third step (step ST4) is a step of forming at least one first through hole T1 and at least one second through hole T2 in the cover 4, which connect the first cavity C1 and the second cavity C2 to the outside, respectively. The fourth step (step ST5) is performed after the second step. The fourth step is a step of filling at least one first through hole T1 and at least one second through hole T2 with getter materials G1 and G2 that adsorb gas. The upper limit value of acceleration detectable by the first acceleration detection unit 51 is lower than the upper limit value of acceleration detectable by the second acceleration detection unit 52. The internal pressure of the first cavity C1 is higher than the internal pressure of the second cavity C2. The internal pressure of the third cavity C3 is lower than the internal pressure of the second cavity C2. The sum of the opening areas of at least one second through hole T2 is larger than the sum of the opening areas of at least one first through hole T1.

[0057] The order of the steps may be changed as appropriate. For example, the cover 4 may be attached to the side portion 32 after at least one first through hole T1 and at least one second through hole T2 are formed in the cover 4.

[0058] (7) Dimensions of the first and second through holes 8 is an enlarged view of the first through hole T1. The maximum width of the first through hole T1 is D, and the depth is F. The first through hole T1 is, for example, a circular hole, and the maximum width D is the diameter.

[0059] The getter material G1 is filled into the first through-hole T1 by sputtering. That is, the material of the getter material G1 becomes particulate and enters the first through-hole T1. The smaller the F / D, the higher the possibility that the sputtered particles will pass through the first through-hole T1 and enter the first cavity C1. In order to prevent the sputtered particles from adhering to the first acceleration detection unit 51 arranged in the first cavity C1, it is preferable that the F / D be a relatively large value.

[0060] 9 represents the minimum F / D at which sputtered particles can pass through the first through hole T1 and enter the first cavity C1 when the incident angle of the sputtered particles in magnetron sputtering is θ. For example, when θ=5.7°, if F / D is less than 10, the sputtered particles can pass through the first through hole T1 and enter the first cavity C1. Therefore, in this case, F / D is preferably 10 or more.

[0061] It is easy to set the main distribution of the incident angle θ of the sputtered particles to about 10°. From Fig. 9, when θ = 10°, it is preferable that F / D is 6 or more. It is preferable to leave some margin and satisfy the condition 10≦F / D.

[0062] Although it has been described herein that the F / D of the first through hole T1 is preferably 10 or more, the same can be said for each of the two or more second through holes T2. That is, it is preferable that the F / D of each of the two or more second through holes T2 is 10 or more.

[0063] Moreover, it becomes difficult to manufacture the first through hole T1 and the second through hole T2 when F / D exceeds 100. Therefore, F / D of each of the first through hole T1 and the two or more second through holes T2 is preferably 100 or less.

[0064] (Modification of the first embodiment) Modifications of the first embodiment are listed below. The following modifications may be implemented in appropriate combination. Hereinafter, the configuration of the first embodiment described above will be referred to as a basic example 1. Configurations similar to those of the basic example 1 will be given the same reference numerals and will not be described.

[0065] (Modification 1 of the first embodiment) 10 is a view of a part of the cover 4 seen from the opposing direction of the base 3 and the cover 4. Note that the protective film 6 and the two or more getter materials G2 are omitted from the illustration.

[0066] 10, when viewed from the opposing direction of the base 3 and the cover 4, the two or more second through holes T2 are provided around an area 5ab that overlaps with the movable part 5a of the second acceleration detection unit 52. More specifically, the two or more second through holes T2 are provided outside the area 5ab, in an area that overlaps with the second cavity C2. The two or more second through holes T2 are arranged so as to surround the area 5ab.

[0067] By providing two or more second through holes T2 around the region 5ab, it is possible to reduce the possibility that the getter material G2 will adhere to the movable part 5a.

[0068] Similarly, when viewed from the opposing direction of the base 3 and the cover 4, the first through-hole T1 is preferably provided around the area 5aa overlapping with the movable part 5a of the first acceleration detection part 51. This can reduce the possibility that the getter material G1 will adhere to the movable part 5a.

[0069] (Other Modifications of the First Embodiment) The first recess R1 or the first space SP1 may constitute the entirety of the first cavity C1, not just a part of it. The second recess R2 or the second space SP2 may constitute the entirety of the second cavity C2, not just a part of it. The third recess R3 or the third space SP3 may constitute the entirety of the third cavity C3, not just a part of it.

[0070] The number of each of the first through hole T1 and the second through hole T2 may be 1 or 2 or more. The sum of the opening areas of the at least one second through hole T2 is preferably larger than the sum of the opening areas of the at least one first through hole T1.

[0071] In Basic Example 1, the second cavity C2 is disposed between the first cavity C1 and the third cavity C3, but such an arrangement is not essential.

[0072] The first through hole T1 does not have to be filled with the getter material G1, in which case the internal pressure of the first cavity C1 becomes equal to the atmospheric pressure.

[0073] (Embodiment 2) Hereinafter, a composite sensor 1A according to the second embodiment and a manufacturing method thereof will be described with reference to Fig. 11. The same components as those in the first basic example will be denoted by the same reference numerals and description thereof will be omitted.

[0074] The composite sensor 1A of this embodiment differs from the basic example 1 in the number of first through holes T1 and the number of second through holes T2. Furthermore, the composite sensor 1A of this embodiment differs from the basic example 1 in that it includes a plurality of outgassing materials M1 and M2 instead of a plurality of getter materials G1 and G2.

[0075] The cover 4 has two or more first through holes T1 connecting the first cavity C1 to the outside, and a second through hole T2 connecting the second cavity C2 to the outside.

[0076] The composite sensor 1A includes two or more outgassing materials M1 and one outgassing material M2. The outgassing materials M1 and M2 are members that generate gas, and the gas is, for example, argon (Ar) gas. The outgassing materials M1 and M2 are formed, for example, by sputtering a metal containing titanium or chromium in an atmosphere into which argon gas is injected. In addition, after the outgassing materials M1 and M2 are formed into a coating by sputtering, argon may be injected into the outgassing materials M1 and M2 by argon plasma irradiation or the like.

[0077] In order to keep the amount of argon gas generated at an appropriate level, it is preferable that the atomic percentage n of argon atoms in each of the multiple outgassing materials M1 and M2 satisfies the condition of 0.1≦n. It is also preferable that the atomic percentage n of argon atoms in each of the multiple outgassing materials M1 and M2 satisfies the condition of n≦20. For example, if the outgassing material M1 is composed of titanium atoms and argon atoms and the ratio of the number of titanium atoms to the number of argon atoms is 9:1, the atomic percentage n of argon atoms in the outgassing material M1 is n=1 / (9+1)×100=10.

[0078] The number of outgassing materials M1 is the same as the number of first through holes T1, and the number of outgassing materials M2 is the same as the number of second through holes T2.

[0079] Each of the two or more first through holes T1 is filled with an outgassing material M1. The second through holes T2 are filled with an outgassing material M2.

[0080] The first cavity C1 is sealed with two or more outgassing materials M1. The second cavity C2 is sealed with an outgassing material M2. The two or more first through holes T1 and the two or more second through holes T2 are filled with two or more outgassing materials M1 and M2, respectively, and a protective film 6 is formed on the two or more outgassing materials M1 and M2.

[0081] The sum of the opening areas of the two or more first through holes T1 is larger than the opening area of ​​the second through holes T2. More specifically, the opening areas of each of the two or more first through holes T1 and each of the two or more second through holes T2 are approximately the same, but the number of the first through holes T1 is greater than the number of the second through holes T2.

[0082] The multiple outgassing materials M1 and M2 generate gas, and thereby the internal pressure of the first cavity C1 and the internal pressure of the second cavity C2 are adjusted. The internal pressure of the first cavity C1 is higher than the internal pressure of the second cavity C2. The internal pressure of the third cavity C3 is lower than the internal pressure of the second cavity C2.

[0083] More specifically, the internal pressure of the first cavity C1 and the second cavity C2 increases as the multiple outgassing materials M1 and M2 generate gas. The first cavity C1 is exposed to the two or more outgassing materials M1 filled in the two or more first through holes T1, and the second cavity C2 is exposed to the outgassing material M2 filled in the second through holes T2. The sum of the opening areas of the two or more first through holes T1 is larger than the opening area of ​​the second through holes T2. Therefore, the amount of gas generated in the first cavity C1 by the two or more outgassing materials M1 is larger than the amount of gas generated in the second cavity C2 by the outgassing material M2. As a result, the internal pressure of the first cavity C1 becomes higher than the internal pressure of the second cavity C2.

[0084] More specifically, when the package 2 is placed under atmospheric pressure after the cover 4 and the bottom wall 31 are joined to the side portion 32, the first cavity C1 and the second cavity C2 take in outside air through the two or more first through holes T1 and the two or more second through holes T2, respectively, and the internal pressure becomes equal to atmospheric pressure. After that, the outgassing materials M1 and M2 are filled, and the outgassing materials M1 and M2 generate gas, thereby increasing the internal pressure of the first cavity C1 and the second cavity C2.

[0085] The positional relationship between the two or more first through holes T1, the first cavity C1, and the first acceleration detection unit 51 in this embodiment is, for example, similar to the positional relationship between the two or more second through holes T2, the second cavity C2, and the second acceleration detection unit 52 in the basic example 1. That is, for example, when viewed from above, the center of the first cavity C1 overlaps with the center of the area in which the two or more first through holes T1 are provided. When viewed from above, the two or more first through holes T1 are provided in an area that overlaps with the first cavity C1. The two or more first through holes T1 are arranged at equal intervals from each other.

[0086] Further, a second through hole T2 is formed at a position overlapping with the center of the second cavity C2 when viewed from above.

[0087] As described in the first modification of the first embodiment, it is also preferable that the two or more first through holes T1 are provided around the area overlapping with the movable part 5a of the first acceleration detection unit 51 when viewed from the opposing direction of the base 3 and the cover 4. It is also preferable that the second through hole T2 is provided around the area overlapping with the movable part 5a of the second acceleration detection unit 52 when viewed from the opposing direction of the base 3 and the cover 4.

[0088] Similarly to Basic Example 1, the ratio F / D of the depth to the maximum width of each of the two or more first through holes T1 and second through holes T2 is preferably 10 or more. Also, F / D is preferably 100 or less.

[0089] Next, the manufacturing method of the composite sensor 1A of this embodiment will be described only in terms of differences from the basic example 1. In step ST4 (see FIG. 7) of forming through holes in the cover 4P, two or more first through holes T1 connected to the first cavity C1 and a second through hole T2 connected to the second cavity C2 are formed. Then, instead of step ST5 (see FIG. 7) of filling the through holes (the first through hole T1 and two or more second through holes T2) with the getter materials G1 and G2 by sputtering in the basic example 1, a step of filling the through holes (the first through hole T1 and two or more second through holes T2) with the outgas materials M1 and M2 by sputtering is performed. After that, instead of step ST6 (see FIG. 7) of removing the getter material G0 of the surface layer formed by sputtering, a step of removing the outgas material of the surface layer formed by sputtering is performed.

[0090] Therefore, the manufacturing method of the composite sensor 1A of this embodiment has the following first to third and fifth steps. The first step is a step of forming the first acceleration detection unit 51, the second acceleration detection unit 52 and the angular velocity detection unit 53 in the first space SP1, the second space SP2 and the third space SP3 provided in the side portion 32, respectively. The second step is a step of attaching the side portion 32 between the bottom wall 31 and the cover 4, and forming the first cavity C1 including the first space SP1, the second cavity C2 including the second space SP2 and the third cavity C3 including the third space SP3 between the bottom wall 31 and the cover 4. The third step is a step of forming at least one first through hole T1 and at least one second through hole T2 in the cover 4, which connect the first cavity C1 and the second cavity C2 to the outside, respectively. The fifth step is a step of filling at least one first through hole T1 and at least one second through hole T2 with outgassing materials M1 and M2 that generate gas. The upper limit value of acceleration detectable by the first acceleration detection unit 51 is lower than the upper limit value of acceleration detectable by the second acceleration detection unit 52. The internal pressure of the first cavity C1 is higher than the internal pressure of the second cavity C2. The internal pressure of the third cavity C3 is lower than the internal pressure of the second cavity C2. The sum of the opening areas of the at least one first through hole T1 is larger than the sum of the opening areas of the at least one second through hole T2.

[0091] The order of each step can be changed as appropriate. For example, at least one first through hole T1 and at least one second through hole T2 may be formed in the cover 4, and then the cover 4 may be attached to the side portion 32. Also, for example, at least one first through hole T1 and at least one second through hole T2 may each be filled with the outgassing materials M1 and M2, and then the cover 4 may be attached to the side portion 32.

[0092] (Modification of the second embodiment) Modifications of the second embodiment are listed below. The following modifications may be implemented in appropriate combination. Hereinafter, the configuration of the second embodiment described above will be referred to as a second basic example. Configurations similar to those of the second basic example will be given the same reference numerals and will not be described.

[0093] The first recess R1 or the first space SP1 may constitute the entirety of the first cavity C1, not just a part of it. The second recess R2 or the second space SP2 may constitute the entirety of the second cavity C2, not just a part of it. The third recess R3 or the third space SP3 may constitute the entirety of the third cavity C3, not just a part of it.

[0094] The number of each of the first through hole T1 and the second through hole T2 may be 1 or may be 2 or more. The sum of the opening area of ​​the at least one first through hole T1 is preferably larger than the sum of the opening area of ​​the at least one second through hole T2.

[0095] In the second basic example, the second cavity C2 is disposed between the first cavity C1 and the third cavity C3, but such an arrangement is not essential.

[0096] The second through hole T2 may not be filled with the outgassing material M2. In this case, the internal pressure of the second cavity C2 becomes equal to the atmospheric pressure.

[0097] The second through holes T2 may be filled with a getter material instead of the outgassing material M2.

[0098] The outgassing materials M1 and M2 may be formed by unbalanced magnetron (UBM) sputtering, which can increase the number of argon atoms contained in the outgassing materials M1 and M2.

[0099] The outgassing materials M1 and M2 are not limited to materials that generate argon gas, but are preferably materials that generate an inert gas such as a rare gas, for example, argon, krypton (Kr), or xenon (Xe).

[0100] (Embodiment 3) Hereinafter, a composite sensor 1B according to the third embodiment and a manufacturing method thereof will be described with reference to Fig. 12. The same components as those in the first basic example will be denoted by the same reference numerals and description thereof will be omitted.

[0101] In the composite sensor 1B of this embodiment, the cover 4 does not have the first through hole T1 and the second through hole T2. Therefore, the composite sensor 1B does not include the getter materials G1 and G2 filled in the first through hole T1 and the second through hole T2, respectively.

[0102] The composite sensor 1B includes an outgassing material M11 disposed in the first cavity C1 and a getter material G3 disposed in the third cavity C3. The outgassing material M11 generates gas. The getter material G3 adsorbs the gas.

[0103] In the manufacturing process of the composite sensor 1B, an outgassing material M11 is placed in the first cavity C1, and a getter material G3 is placed in the third cavity C3. Then, in an atmosphere of a predetermined pressure, the cover 4 and the bottom wall 31 are joined to the side portion 32 to seal the first cavity C1, the second cavity C2, and the third cavity C3.

[0104] The internal pressure of the second cavity C2 becomes the predetermined pressure. In the first cavity C1, the internal pressure becomes higher than the predetermined pressure because gas is generated from the outgassing material M11. In the third cavity C3, the getter material G3 adsorbs the gas, so the internal pressure becomes lower than the predetermined pressure.

[0105] The composition of the getter material G3 may be similar to the composition of the getter materials G1 and G2 of Basic Example 1. The composition of the outgassing material M11 may be similar to the composition of the outgassing materials M1 and M2 of Basic Example 2.

[0106] (Modification of the third embodiment) Modifications of the third embodiment are listed below. The following modifications may be implemented in appropriate combination. Hereinafter, the configuration of the third embodiment described above will be referred to as a third basic example. Configurations similar to those of the third basic example will be given the same reference numerals and will not be described.

[0107] (Modification 1 of the third embodiment) Fig. 13 is a cross-sectional view of a composite sensor 1C according to Modification 1. As shown in Fig. 13, in Modification 1, the outgassing material and the getter material are also disposed in the second cavity C2. That is, the composite sensor 1C further includes an outgassing material M22 and a getter material G22 disposed in the second cavity C2. The other configurations are the same as those of the basic example 3.

[0108] In this first modification, the internal pressure of the second cavity C2 can be adjusted by the outgassing material M22 and the getter material G22.

[0109] In the manufacturing process of the composite sensor 1C, the cover 4 and the bottom wall 31 are joined to the side portion 32 in an atmosphere of a predetermined pressure to seal the second cavity C2. After that, the internal pressure of the second cavity C2 is adjusted by the outgassing material M22 and the getter material G22. Even if the predetermined pressure is, for example, atmospheric pressure, the internal pressure of the second cavity C2 can be made different from atmospheric pressure. In other words, the configuration of the composite sensor 1C of this modified example 1 is also suitable for performing the operation of joining the cover 4 to the base 3 under atmospheric pressure.

[0110] (Other Modifications of the Third Embodiment) The first recess R1 or the first space SP1 may constitute the entirety of the first cavity C1, not just a part of it. The second recess R2 or the second space SP2 may constitute the entirety of the second cavity C2, not just a part of it. The third recess R3 or the third space SP3 may constitute the entirety of the third cavity C3, not just a part of it.

[0111] In the basic example 3, the second cavity C2 is disposed between the first cavity C1 and the third cavity C3, but such an arrangement is not essential.

[0112] The outgassing materials M11 and M22 may be formed by unbalanced magnetron (UBM) sputtering, which can increase the number of argon atoms contained in the outgassing materials M11 and M22.

[0113] The outgassing materials M11 and M22 are not limited to materials that generate argon gas, but are preferably materials that generate an inert gas such as a rare gas. The rare gas is, for example, argon, krypton (Kr), or xenon (Xe). In particular, the gas generated from the outgassing material M22 is preferably a rare gas that is difficult to be adsorbed by the getter material G22.

[0114] As in Basic Example 1 or 2, the cover 4 may have at least one of the first through hole T1 and the second through hole T2 filled with a getter material or an outgassing material.

[0115] (summary) The above-described embodiments and the like disclose the following aspects.

[0116] A composite sensor (1; 1A; 1B; 1C) according to a first aspect includes a package (2), a first acceleration detection unit (51), a second acceleration detection unit (52), and an angular velocity detection unit (53). The package (2) has a first cavity (C1), a second cavity (C2), and a third cavity (C3) therein. The first acceleration detection unit (51) is disposed in the first cavity (C1). The second acceleration detection unit (52) is disposed in the second cavity (C2). The angular velocity detection unit (53) is disposed in the third cavity (C3). The upper limit value of acceleration detectable by the first acceleration detection unit (51) is smaller than the upper limit value of acceleration detectable by the second acceleration detection unit (52). The internal pressure of the first cavity (C1) is higher than the internal pressure of the second cavity (C2), and the internal pressure of the third cavity (C3) is lower than the internal pressure of the second cavity (C2).

[0117] According to the above configuration, the angular velocity detection unit (53) and the first acceleration detection unit (51) and the second acceleration detection unit (52), each of which has a different upper limit value of detectable acceleration, can be integrated into one package (2). By providing a difference in internal pressure, it is possible to suppress a decrease in detection accuracy caused by the first acceleration detection unit (51) and the second acceleration detection unit (52) vibrating at their resonant frequencies. In addition, by lowering the internal pressure of the third cavity (C3) in which the angular velocity detection unit (53) is arranged, it is possible to suppress a decrease in characteristics related to the detection accuracy of the angular velocity detection unit (53). Therefore, it is possible to suppress a decrease in detection accuracy while integrating three detection units into one package (2).

[0118] In the composite sensor (1) according to the second aspect, in the first aspect, the package (2) includes a base (3) and a cover (4). The base (3) has a first recess (R1) constituting at least a part of the first cavity (C1), a second recess (R2) constituting at least a part of the second cavity (C2), and a third recess (R3) constituting at least a part of the third cavity (C3), and a first opening (OP1), a second opening (OP2), and a third opening (OP3) that open the first recess (R1), the second recess (R2), and the third recess (R3) to the outside of the base (3), respectively. The cover (4) covers the first opening (OP1), the second opening (OP2), and the third opening (OP3). The cover (4) has at least one first through hole (T1) and at least one second through hole (T2) that connect the first cavity (C1) and the second cavity (C2) to the outside, respectively. The composite sensor (1) further includes a getter material (G1; G2) that adsorbs gas. The getter material (G1; G2) is filled in each of the at least one first through hole (T1) and the at least one second through hole (T2). The sum of the opening areas of the at least one second through hole (T2) is greater than the sum of the opening areas of the at least one first through hole (T1).

[0119] According to the above configuration, the getter material (G1; G2) adsorbs gas, so that a difference in internal pressure can be created. Moreover, the internal pressure can be adjusted by adjusting the total opening area of ​​at least one first through hole (T1) and the total opening area of ​​at least one second through hole (T2).

[0120] In the composite sensor (1A) according to the third aspect, in the first aspect, the package (2) includes a base (3) and a cover (4). The base (3) has a first recess (R1) constituting at least a part of the first cavity (C1), a second recess (R2) constituting at least a part of the second cavity (C2), and a third recess (R3) constituting at least a part of the third cavity (C3), and a first opening (OP1), a second opening (OP2), and a third opening (OP3) that open the first recess (R1), the second recess (R2), and the third recess (R3) to the outside of the base (3), respectively. The cover (4) covers the first opening (OP1), the second opening (OP2), and the third opening (OP3). The cover (4) has at least one first through hole (T1) and at least one second through hole (T2) that connect the first cavity (C1) and the second cavity (C2) to the outside, respectively. The composite sensor (1A) further includes an outgassing material (M1; M2) that generates gas. The outgassing material (M1; M2) is filled in each of the at least one first through hole (T1) and the at least one second through hole (T2). The sum of the opening areas of the at least one first through hole (T1) is greater than the sum of the opening areas of the at least one second through hole (T2).

[0121] According to the above-mentioned configuration, the outgassing material (M1; M2) generates gas, so that a difference in the internal pressure can be created. Moreover, the internal pressure can be adjusted by adjusting the total opening area of ​​at least one first through hole (T1) and the total opening area of ​​at least one second through hole (T2).

[0122] In the composite sensor (1) according to the fourth aspect, in the second aspect, the number of the at least one second through hole (T2) is greater than the number of the at least one first through hole (T1).

[0123] According to the above configuration, the internal pressure can be adjusted by adjusting the number of the at least one first through hole (T1) and the number of the at least one second through hole (T2).

[0124] In the composite sensor (1A) according to the fifth aspect, in the third aspect, the number of the at least one first through hole (T1) is greater than the number of the at least one second through hole (T2).

[0125] According to the above configuration, the internal pressure can be adjusted by adjusting the number of the at least one first through hole (T1) and the number of the at least one second through hole (T2).

[0126] In addition, in the composite sensor (1;1A) according to the sixth aspect, in any one of the second to fifth aspects, at least one first through hole (T1) and at least one second through hole (T2) each satisfy the condition 10≦F / D, where D is the maximum width and F is the depth.

[0127] According to the above configuration, when the getter material (G1; G2) or the outgassing material (M1; M2) is filled into at least one first through hole (T1) and at least one second through hole (T2), the possibility of the getter material (G1; G2) or the outgassing material (M1; M2) reaching the first cavity (C1) or the second cavity (C2) can be reduced.

[0128] In addition, in the composite sensor (1;1A) according to the seventh aspect, in any one of the second to sixth aspects, at least one first through hole (T1) is provided around an area (5aa) overlapping with the movable part (5a) of the first acceleration detection part (51) when viewed from the opposing direction of the base (3) and the cover (4).

[0129] According to the above-mentioned configuration, it is possible to reduce the possibility that the getter material (G1; G2) or the outgassing material (M1; M2) will adhere to the movable part (5a).

[0130] In addition, in the composite sensor (1;1A) according to the eighth aspect, in any one of the second to seventh aspects, at least one second through hole (T2) is provided around an area (5ab) overlapping with the movable part (5a) of the second acceleration detection part (52) when viewed from the opposing direction of the base (3) and the cover (4).

[0131] According to the above-mentioned configuration, it is possible to reduce the possibility that the getter material (G1; G2) or the outgassing material (M1; M2) will adhere to the movable part (5a).

[0132] In addition, the composite sensor (1B; 1C) according to the ninth aspect is any one of the first to eighth aspects, and further includes an outgassing material (M11) arranged in the first cavity (C1) and generating gas, and a getter material (G3) arranged in the third cavity (C3) and adsorbing gas.

[0133] According to the above-mentioned configuration, the getter material (G3) adsorbs gas and the outgassing material (M11) generates gas, so that a difference in the internal pressure can be created. Moreover, the internal pressure can be adjusted by adjusting the amount of each of the getter material (G3) and the outgassing material (M11).

[0134] In the composite sensor (1C) according to the tenth aspect, in the ninth aspect, the outgassing material (M22) and the getter material (G22) are also disposed in the second cavity (C2).

[0135] According to the above configuration, the internal pressure of the second cavity (C2) can be adjusted.

[0136] In addition, in the composite sensor (1A; 1B; 1C) according to the eleventh aspect, in the third, fifth, ninth or tenth aspect, the outgassing material (M1; M2; M11; M22) satisfies the condition that the atomic percentage n of argon atoms is 0.1≦n.

[0137] According to the above configuration, a sufficient amount of argon gas is generated from the outgassing materials (M1; M2; M11; M22).

[0138] In addition, in the composite sensor (1A; 1B; 1C) according to the twelfth aspect, in the third, fifth, ninth, tenth or eleventh aspect, the outgassing material (M1; M2; M11; M22) satisfies the condition that the atomic percentage n of argon atoms is n≦20.

[0139] According to the above configuration, the amount of argon gas generated from the outgassing materials (M1; M2; M11; M22) can be kept at an appropriate level.

[0140] The configurations other than those of the first aspect are not essential to the composite sensor (1; 1A; 1B; 1C) and may be omitted as appropriate.

[0141] A manufacturing method according to a thirteenth aspect is a manufacturing method for a composite sensor (1) including a package (2) including a bottom wall (31), a side portion (32), and a cover (4), and includes first to third steps. The first step is a step of forming a first acceleration detection unit (51), a second acceleration detection unit (52), and an angular velocity detection unit (53) in a first space (SP1), a second space (SP2), and a third space (SP3) provided in the side portion (32), respectively. The second step is a step of attaching the side portion (32) between the bottom wall (31) and the cover (4), and forming a first cavity (C1) including the first space (SP1), a second cavity (C2) including the second space (SP2), and a third cavity (C3) including the third space (SP3) between the bottom wall (31) and the cover (4). The third step is a step of forming at least one first through hole (T1) and at least one second through hole (T2) in the cover (4) for connecting the first cavity (C1) and the second cavity (C2) to the outside, respectively. The fourth step is performed after the second step. The fourth step is a step of filling each of the at least one first through hole (T1) and the at least one second through hole (T2) with a getter material (G1; G2) that adsorbs gas. The upper limit value of acceleration that the first acceleration detection unit (51) can detect is lower than the upper limit value of acceleration that the second acceleration detection unit (52) can detect. The internal pressure of the first cavity (C1) is higher than the internal pressure of the second cavity (C2). The internal pressure of the third cavity (C3) is lower than the internal pressure of the second cavity (C2). The sum of the opening areas of the at least one second through hole (T2) is greater than the sum of the opening areas of the at least one first through hole (T1).

[0142] According to the above configuration, the getter material (G1; G2) adsorbs gas, so that a difference in internal pressure can be created. Moreover, the internal pressure can be adjusted by adjusting the total opening area of ​​at least one first through hole (T1) and the total opening area of ​​at least one second through hole (T2).

[0143] A manufacturing method according to a fourteenth aspect is a manufacturing method for a composite sensor (1A) having a package (2) including a bottom wall (31), a side portion (32), and a cover (4), and includes first to third and fifth steps. The first step is a step of forming a first acceleration detection unit (51), a second acceleration detection unit (52), and an angular velocity detection unit (53) in a first space (SP1), a second space (SP2), and a third space (SP3) provided in the side portion (32), respectively. The second step is a step of attaching the side portion (32) between the bottom wall (31) and the cover (4), and forming a first cavity (C1) including the first space (SP1), a second cavity (C2) including the second space (SP2), and a third cavity (C3) including the third space (SP3) between the bottom wall (31) and the cover (4). The third step is to form at least one first through hole (T1) and at least one second through hole (T2) in the cover (4) to connect the first cavity (C1) and the second cavity (C2) to the outside, respectively. The fifth step is to fill each of the at least one first through hole (T1) and the at least one second through hole (T2) with an outgassing material (M1; M2) that generates gas. The upper limit value of acceleration detectable by the first acceleration detection unit (51) is lower than the upper limit value of acceleration detectable by the second acceleration detection unit (52). The internal pressure of the first cavity (C1) is higher than the internal pressure of the second cavity (C2). The internal pressure of the third cavity (C3) is lower than the internal pressure of the second cavity (C2). The sum of the opening areas of the at least one first through hole (T1) is greater than the sum of the opening areas of the at least one second through hole (T2).

[0144] According to the above-mentioned configuration, the outgassing material (M1; M2) generates gas, so that a difference in the internal pressure can be created. Moreover, the internal pressure can be adjusted by adjusting the total opening area of ​​at least one first through hole (T1) and the total opening area of ​​at least one second through hole (T2). [Explanation of symbols]

[0145] 1;1A;1B;1C Combined Sensor 2 Package 3. Bass 4 Cover 5a Moving part 5aa area 5ab area 31 Bottom Wall 32 Side 51 First acceleration detection unit 52 Second acceleration detection unit 53 Angular velocity detector C1 First cavity C2 Second Cavity C3 Third Cavity G1;G2;G3;G22 getter material M1;M2;M11;M22 Outgassing Materials OP1 First opening OP2 Second opening OP3 Third opening R1 First recess R2 Second recess R3 Third recess SP1 First Space SP2 Second Space SP3 The Third Space T1 First through hole T2 Second Through Hole

Claims

1. a package having a first cavity, a second cavity, and a third cavity therein; a first acceleration detection unit disposed in the first cavity; a second acceleration detection unit disposed in the second cavity; an angular velocity detection unit disposed in the third cavity; an upper limit value of acceleration detectable by the first acceleration detection unit is smaller than an upper limit value of acceleration detectable by the second acceleration detection unit; the internal pressure of the first cavity is higher than the internal pressure of the second cavity; the internal pressure of the third cavity is lower than the internal pressure of the second cavity; Composite sensor.

2. The package includes a base and a cover. The base is a first recess constituting at least a part of the first cavity, a second recess constituting at least a part of the second cavity, and a third recess constituting at least a part of the third cavity; a first opening, a second opening, and a third opening that open the first recess, the second recess, and the third recess, respectively, to the outside of the base; the cover covers the first opening, the second opening, and the third opening; the cover has at least one first through hole and at least one second through hole connecting the first cavity and the second cavity to the outside, respectively; The at least one first through hole and the at least one second through hole are filled with a getter material that adsorbs a gas, A sum of an opening area of ​​the at least one second through hole is greater than a sum of an opening area of ​​the at least one first through hole; The composite sensor according to claim 1 .

3. The package includes a base and a cover. The base is a first recess constituting at least a part of the first cavity, a second recess constituting at least a part of the second cavity, and a third recess constituting at least a part of the third cavity; a first opening, a second opening, and a third opening that open the first recess, the second recess, and the third recess, respectively, to the outside of the base; the cover covers the first opening, the second opening, and the third opening; the cover has at least one first through hole and at least one second through hole connecting the first cavity and the second cavity to the outside, respectively; The at least one first through hole and the at least one second through hole are filled with an outgassing material that generates a gas, A sum of an opening area of ​​the at least one first through hole is greater than a sum of an opening area of ​​the at least one second through hole; The composite sensor according to claim 1 .

4. The number of the at least one second through hole is greater than the number of the at least one first through hole. The composite sensor according to claim 2 .

5. The number of the at least one first through hole is greater than the number of the at least one second through hole. The composite sensor according to claim 3 .

6. In each of the at least one first through hole and the at least one second through hole, a maximum width is D and a depth is F, and a condition of 10≦F / D is satisfied. The composite sensor according to any one of claims 2 to 5.

7. When viewed from a direction in which the base and the cover face each other, the at least one first through hole is provided around a region overlapping with a movable portion of the first acceleration detection portion. The composite sensor according to any one of claims 2 to 5.

8. When viewed from a direction in which the base and the cover face each other, the at least one second through hole is provided around a region overlapping with a movable portion of the second acceleration detection portion. The composite sensor according to any one of claims 2 to 5.

9. an outgassing material disposed in the first cavity and configured to generate a gas; A getter material disposed in the third cavity and configured to adsorb gas. The composite sensor according to claim 1 .

10. The outgassing material and the getter material are also disposed in the second cavity. The composite sensor according to claim 9.

11. The outgassing material has an atomic percentage n of argon atoms that satisfies the condition 0.1≦n.

11. The composite sensor according to claim 3, 5, 9 or 10.

12. The outgassing material has an atomic percentage n of argon atoms that satisfies the condition n≦20; 11. The composite sensor according to claim 3, 5, 9 or 10.

13. 1. A method for manufacturing a composite sensor having a package including a bottom wall, a side portion, and a cover, comprising: a first step of forming a first acceleration detection unit, a second acceleration detection unit, and an angular velocity detection unit in a first space, a second space, and a third space provided in the side portion, respectively; a second step of attaching the side portion between the bottom wall and the cover to form a first cavity including the first space, a second cavity including the second space, and a third cavity including the third space between the bottom wall and the cover; a third step of forming at least one first through hole and at least one second through hole in the cover, the first cavity and the second cavity respectively connecting to the outside; and a fourth step of filling each of the at least one first through hole and the at least one second through hole with a getter material that adsorbs a gas, after the second step, an upper limit value of acceleration detectable by the first acceleration detection unit is smaller than an upper limit value of acceleration detectable by the second acceleration detection unit; the internal pressure of the first cavity is higher than the internal pressure of the second cavity; the internal pressure of the third cavity is lower than the internal pressure of the second cavity; A sum of an opening area of ​​the at least one second through hole is greater than a sum of an opening area of ​​the at least one first through hole; Manufacturing method.

14. A method for manufacturing a composite sensor having a package including a bottom wall, a side portion, and a cover, comprising: a first step of forming a first acceleration detection unit, a second acceleration detection unit, and an angular velocity detection unit in a first space, a second space, and a third space provided in the side portion, respectively; a second step of attaching the side portion between the bottom wall and the cover to form a first cavity including the first space, a second cavity including the second space, and a third cavity including the third space between the bottom wall and the cover; a third step of forming at least one first through hole and at least one second through hole in the cover, the first cavity and the second cavity respectively connecting to the outside; and a fifth step of filling each of the at least one first through hole and the at least one second through hole with an outgassing material that generates a gas, an upper limit value of acceleration detectable by the first acceleration detection unit is smaller than an upper limit value of acceleration detectable by the second acceleration detection unit; the internal pressure of the first cavity is higher than the internal pressure of the second cavity; the internal pressure of the third cavity is lower than the internal pressure of the second cavity; A sum of an opening area of ​​the at least one first through hole is greater than a sum of an opening area of ​​the at least one second through hole; Manufacturing method.

Images