JP2018100882A - Pressure sensor, method for manufacturing pressure sensor, pressure sensor module, electronic apparatus, and mobile body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor which has a high pressure detection sensitivity and can suppress reduction in the reliability, a method for manufacturing the pressure sensor, a pressure sensor module, an electronic apparatus, and a mobile body.SOLUTION: The pressure sensor includes: a diaphragm which is deflected and deformed by pressures; a sensor part in the diaphragm; and a first silicon nitride film on one surface of the diaphragm, the first silicon nitride film containing hydrogen in a concentration of 10 atom% or less, and the pressure sensor further having a wiring electrically connected to the sensor part and a second silicon nitride film covering at least a part of the wiring.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure sensor, a pressure sensor manufacturing method, a pressure sensor module, an electronic device, and a moving body.

  Conventionally, for example, a configuration described in Patent Document 1 is known as a pressure sensor. The pressure sensor of Patent Document 1 has a diaphragm that is bent and deformed by receiving pressure, and a piezoresistive element formed on the diaphragm, and utilizes the fact that the resistance value of the piezoresistive element changes based on the deflection of the diaphragm. The pressure is detected.

International Publication No. 2010/055734

In the pressure sensor disclosed in Patent Document 1, a protective film made of a silicon oxide film (SiO ₂ film) is formed on the upper surface of the diaphragm in order to protect the circuit portion including the piezoresistive element. However, the silicon oxide film easily allows moisture, gas, etc. to pass through, and the components of the silicon oxide film (moisture, gas, etc.) have deteriorated the reaction of the circuit part, etc., reducing the reliability of the pressure sensor. End up. Further, when the protective film is made thicker in order to suppress this deterioration, the diaphragm is difficult to bend, and the pressure detection sensitivity is lowered.

  An object of the present invention is to provide a pressure sensor, a pressure sensor manufacturing method, a pressure sensor module, an electronic apparatus, and a moving body that have high pressure detection sensitivity and can suppress a decrease in reliability.

  Such an object is achieved by the present invention described below.

The pressure sensor of the present invention includes a diaphragm that bends and deforms by receiving pressure,
A sensor provided in the diaphragm;
A first silicon nitride film provided on one surface side of the diaphragm,
The hydrogen content of the first silicon nitride film is 10 atomic% or less.
Thereby, a denser first silicon nitride film is obtained. Therefore, pinholes are hardly generated, and the barrier function of the first silicon nitride film can be further enhanced. Therefore, the sensor unit can be more effectively protected from moisture, gas, and the like, and the pressure sensor is highly reliable (deterioration of the pressure sensor reliability can be suppressed). Further, since the first silicon nitride film can be made thin, the pressure detection sensitivity can be increased.

In the pressure sensor of the present invention, wiring electrically connected to the sensor unit,
And a second silicon nitride film covering at least a part of the wiring.
Thereby, the wiring can be protected from moisture or the like by the second silicon nitride film.

The pressure sensor of the present invention includes a diaphragm that bends and deforms by receiving pressure,
A sensor provided in the diaphragm;
A first silicon nitride film provided on one surface side of the diaphragm;
Wiring electrically connected to the sensor unit;
A second silicon nitride film covering at least a part of the wiring,
The hydrogen content of the first silicon nitride film is lower than the hydrogen content of the second silicon nitride film.
Thereby, a denser first silicon nitride film is obtained. Therefore, pinholes are hardly generated, and the barrier function of the first silicon nitride film can be further enhanced. Therefore, the sensor unit can be more effectively protected from moisture, gas, and the like, and the pressure sensor is highly reliable (deterioration of the reliability of the pressure sensor 1 can be suppressed). Further, the first silicon nitride film and the second silicon nitride film can be formed more easily.

In the pressure sensor of the present invention, the hydrogen content of the first silicon nitride film is preferably 10 atomic% or less.
Thereby, the barrier function of the first silicon nitride film can be further enhanced. Therefore, the sensor unit can be more effectively protected from moisture, gas, and the like.

The pressure sensor according to the present invention preferably includes a silicon oxide film provided between the first silicon nitride film and the diaphragm.
Thereby, more excellent pressure detection characteristics can be exhibited.

In the pressure sensor of the present invention, it is preferable that the first silicon nitride film has a thickness of 200 nm or less.
Thereby, the first silicon nitride film can be made sufficiently thin while sufficiently exhibiting the barrier characteristics. Therefore, the pressure detection sensitivity of the pressure sensor can be improved.

In the pressure sensor of the present invention, it is preferable that the second silicon nitride film is thicker than the first silicon nitride film.
Thereby, the first silicon nitride film can be thinned, and the pressure detection sensitivity of the pressure sensor can be improved. Further, the second silicon nitride film can be thickened, and the barrier function of the second silicon nitride film can be enhanced.

The pressure sensor according to the present invention preferably has a pressure reference chamber disposed on the other surface side of the diaphragm.
Thereby, the pressure received by the diaphragm can be detected with reference to the pressure in the pressure reference chamber. Therefore, it is possible to detect the pressure with a relatively simple configuration and with high accuracy.

The method of manufacturing a pressure sensor of the present invention includes a step of forming a sensor portion on a substrate,
Disposing a first silicon nitride film having a hydrogen content of 10 atomic% or less on one surface side of the substrate;
Forming a concave portion on the other surface side of the substrate and forming a diaphragm that is bent and deformed by pressure reception.
As a result, a denser first silicon nitride film having excellent barrier properties can be obtained, and the sensor portion can be more effectively protected from moisture, gas, and the like. Therefore, a highly reliable pressure sensor can be obtained.

The method of manufacturing a pressure sensor of the present invention includes a step of forming a sensor portion on a substrate,
Disposing a first silicon nitride film on one surface side of the substrate;
Arranging a wiring electrically connected to the sensor unit on one surface side of the substrate;
Disposing a second silicon nitride film covering at least part of the wiring;
Forming a recess on the other surface side of the substrate, and forming a diaphragm that bends and deforms under pressure.
The hydrogen content of the first silicon nitride film is lower than the hydrogen content of the second silicon nitride film.
As a result, a denser first silicon nitride film having excellent barrier properties can be obtained, and the sensor portion can be more effectively protected from moisture, gas, and the like. Therefore, a highly reliable pressure sensor can be obtained.

The pressure sensor module of the present invention includes the pressure sensor of the present invention,
And a package housing the pressure sensor.
Thereby, a pressure sensor module with high sensitivity and high reliability can be obtained.

The electronic device of the present invention includes the pressure sensor of the present invention.
Thereby, a high-performance and highly reliable electronic device can be obtained.

The moving body of the present invention has the pressure sensor of the present invention.
As a result, a mobile body with high performance and high reliability can be obtained.

It is sectional drawing of the pressure sensor which concerns on 1st Embodiment of this invention. It is a top view which shows the sensor part which the pressure sensor shown in FIG. 1 has. It is a figure which shows the bridge circuit containing the sensor part shown in FIG. It is a flowchart which shows the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing of the pressure sensor which concerns on 2nd Embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the pressure sensor shown in FIG. It is sectional drawing of the pressure sensor which concerns on 3rd Embodiment of this invention. It is sectional drawing of the pressure sensor which concerns on 4th Embodiment of this invention. It is sectional drawing of the pressure sensor module which concerns on 5th Embodiment of this invention. It is a top view of the support substrate which the pressure sensor module shown in FIG. 21 has. It is a perspective view which shows the altimeter as an electronic device which concerns on 6th Embodiment of this invention. It is a front view which shows the navigation system as an electronic device which concerns on 7th Embodiment of this invention. It is a perspective view which shows the motor vehicle as a moving body which concerns on 8th Embodiment of this invention.

  Hereinafter, a pressure sensor, a pressure sensor manufacturing method, a pressure sensor module, an electronic device, and a moving body according to the present invention will be described in detail based on embodiments shown in the accompanying drawings.

<First Embodiment>
First, the pressure sensor according to the first embodiment of the present invention will be described.

  FIG. 1 is a cross-sectional view of a pressure sensor according to a first embodiment of the present invention. FIG. 2 is a plan view showing a sensor unit included in the pressure sensor shown in FIG. FIG. 3 is a diagram illustrating a bridge circuit including the sensor unit illustrated in FIG. 2. FIG. 4 is a flowchart showing a manufacturing method of the pressure sensor shown in FIG. 5 to 14 are cross-sectional views for explaining a method of manufacturing the pressure sensor shown in FIG. In the following description, the upper side in FIGS. 1 and 5 to 14 is also referred to as “upper”, and the lower side is also referred to as “lower”.

  As shown in FIG. 1, the pressure sensor 1 includes a substrate 2, a sensor unit 3 disposed on the substrate 2, a base substrate 4 bonded to the substrate 2, and the substrate 2 and the base substrate 4. And a pressure reference chamber S that is formed.

  The substrate 2 is an SOI substrate (that is, a substrate in which the first silicon layer 2a, the silicon oxide layer 2b, and the second silicon layer 2c are stacked in this order). However, as the substrate 2, for example, a single layer silicon substrate may be used instead of the SOI substrate. Further, a semiconductor substrate other than a silicon substrate may be used.

  Further, the substrate 2 is provided with a diaphragm 21 that is thinner than the surrounding portion and is bent and deformed by receiving pressure. The substrate 2 is formed with a bottomed recess 22 that opens downward, and the diaphragm 21 is above the recess 22 (the portion where the substrate 2 is thinned by the recess 22). The upper surface of the diaphragm 21 is a pressure receiving surface that receives pressure. The concave portion 22 is a space (hollow portion) for forming a pressure reference chamber S (described later) formed on the side opposite to the pressure receiving surface of the diaphragm 21. In the present embodiment, the planar view shape of the diaphragm 21 is substantially square, but the planar view shape of the diaphragm 21 is not particularly limited, and may be, for example, a circular shape.

  Here, in this embodiment, the recess 22 is formed by dry etching using a silicon deep etching apparatus. Specifically, the recesses 22 are formed by digging the first silicon layer 2a by repeating the processes of isotropic etching, protective film formation, and anisotropic etching from the lower surface side of the substrate 2. This process is repeated, and when the etching reaches the silicon oxide layer 2b, the silicon oxide layer 2b serves as an etching stopper to complete the etching, and the recess 22 is obtained. According to such a forming method, since the side surface of the recess 22 is substantially perpendicular to the main surface of the substrate 2, the opening area of the recess 22 can be reduced. Therefore, a decrease in mechanical strength of the substrate 2 can be suppressed, and an increase in the size of the pressure sensor 1 can be suppressed. In addition, although not shown in the figure, periodic unevenness is formed in the digging direction on the inner wall side surface of the recess 22 by repeating the above-described steps.

  However, the method of forming the recess 22 is not limited to the above method, and may be formed by wet etching, for example. In the present embodiment, the silicon oxide layer 2b remains on the diaphragm 21, but the silicon oxide layer 2b may be further removed. That is, the diaphragm 21 may be constituted by a single layer of the second silicon layer 2c. Thereby, the diaphragm 21 can be made thinner, and the diaphragm 21 which is easier to bend and deform is obtained.

  The thickness of the diaphragm 21 is not particularly limited, and varies depending on the size of the diaphragm 21. For example, when the width of the diaphragm 21 is 100 μm or more and 150 μm or less, the thickness is preferably 1 μm or more and 10 μm or less. More preferably, it is 1 μm or more and 3 μm or less. With such a thickness, it is possible to obtain a diaphragm 21 that is sufficiently thin while maintaining sufficient mechanical strength, and that is easily deformed by receiving pressure, that is, has high sensitivity.

The silicon oxide film 28 (SiO ₂ film) and the first silicon nitride film 29 (SiN film) are formed on the upper surface of the substrate 2 as described above. More specifically, a silicon oxide film 28 is formed on the upper surface of the substrate 2, and a first silicon nitride film 29 is formed on the upper surface of the silicon oxide film 28. The silicon oxide film 28 and the first silicon nitride film 29 are arranged so as to overlap the entire area of the diaphragm 21 in plan view of the substrate 2.

  With the silicon oxide film 28, it is possible to reduce the interface state of piezoresistive elements 31, 32, 33, and 34, which will be described later, which the sensor unit 3 has, thereby suppressing the generation of noise. The first silicon nitride film 29 can protect the sensor unit 3 from moisture and dust.

  Here, the total thickness (total thickness) of the silicon oxide film 28 and the first silicon nitride film 29 is not particularly limited, but is preferably 1/10 or less of the thickness of the diaphragm 21. More preferably, it is 100 or less. Thereby, the silicon oxide film 28 and the first silicon nitride film 29 can be made sufficiently thin.

  Further, the thickness of the silicon oxide film 28 is not particularly limited, but when the thickness of the diaphragm 21 is about 1 μm or more and 10 μm or less, for example, it is preferably 5 nm or more and 100 nm or less, and preferably 5 nm or more and 50 nm or less. More preferably. Thereby, the silicon oxide film 28 can be made sufficiently thin while sufficiently exhibiting the above-described effects.

  Further, the thickness T1 of the first silicon nitride film 29 is not particularly limited. However, when the thickness of the diaphragm 21 is about 1 μm or more and 10 μm or less, for example, it is preferably 10 nm or more and 200 nm or less. More preferably, it is 50 nm or less. Thereby, the first silicon nitride film 29 can be made sufficiently thin while sufficiently exhibiting the above-described effects. In particular, the first silicon nitride film 29 is a dense film whose hydrogen content is suppressed to 10 atomic% or less, as will be described later. Can be demonstrated.

  The silicon oxide film 28 may be omitted. Further, instead of the silicon oxide film 28, a film made of another material (for example, SiNO) may be disposed.

  The diaphragm 21 is provided with a sensor unit 3 that can detect the pressure acting on the diaphragm 21. As shown in FIG. 2, the sensor unit 3 includes four piezoresistive elements 31, 32, 33, and 34 provided on the diaphragm 21. Further, the piezoresistive elements 31, 32, 33, and 34 are electrically connected to each other via a wiring 35 to constitute a bridge circuit 30 (Wheatstone bridge circuit) shown in FIG. The bridge circuit 30 is connected to a drive circuit (not shown) that supplies a drive voltage AVDC. The bridge circuit 30 outputs a detection signal (voltage) corresponding to a change in resistance value of the piezoresistive elements 31, 32, 33, and 34 based on the deflection of the diaphragm 21. Therefore, the pressure received by the diaphragm 21 can be detected based on the output detection signal.

  In particular, the piezoresistive elements 31, 32, 33, and 34 are disposed on the outer edge portion of the diaphragm 21. When the diaphragm 21 is bent and deformed by pressure reception, a large stress is particularly applied to the outer edge portion of the diaphragm 21. Therefore, by arranging the piezoresistive elements 31, 32, 33, and 34 on the outer edge portion, the above-described detection signal is increased. This improves the sensitivity of pressure detection. The arrangement of the piezoresistive elements 31, 32, 33, and 34 is not particularly limited. For example, the piezoresistive elements 31, 32, 33, and 34 may be arranged across the outer edge of the diaphragm 21.

  Further, as described above, the following effects can be exhibited by thinning the silicon oxide film 28 and the first silicon nitride film 29. In the present embodiment, it can be said that the laminated body of the diaphragm 21 and the silicon oxide film 28 and the first silicon nitride film 29 on the diaphragm 21 functions as a “diaphragm” that is bent and deformed by receiving pressure. If this diaphragm is discussed in the thickness direction, the stress generated when the diaphragm is bent and deformed by pressure from the central portion in the thickness direction of the diaphragm toward the surface (upper surface and lower surface) becomes large. Therefore, by arranging the piezoresistive elements 31, 32, 33, 34 closer to the upper surface or the lower surface of the diaphragm, a larger detection signal can be obtained even when the same pressure is applied. In view of this point, as described above, by thinning the silicon oxide film 28 and the first silicon nitride film 29, the piezoresistive elements 31, 32, 33, and 34 are made diaphragms (diaphragm 21, silicon oxide film 28, and first oxide film 28). 1 can be arranged closer to the upper surface of the laminate (with the silicon nitride film 29), a larger detection signal can be obtained, and the pressure detection sensitivity can be further improved.

  Each of the piezoresistive elements 31, 32, 33, and 34 is configured, for example, by doping (diffusing or injecting) impurities such as phosphorus and boron into the second silicon layer 2c of the substrate 2. The wiring 35 is configured by doping (diffusing or injecting) impurities such as phosphorus and boron at a higher concentration than the piezoresistive elements 31, 32, 33, and 34 into the second silicon layer 2 c of the substrate 2, for example. Has been.

  An interlayer insulating film 51 is disposed on the substrate 2, and a wiring 52 is provided on the interlayer insulating film 51. Further, a through hole is formed in the interlayer insulating film 51, and the wiring 52 is electrically connected to the wiring 35 through this through hole. An interlayer insulating film 53 is provided on the interlayer insulating film 51 and the wiring 52, and the wiring 52 is insulated and protected by the interlayer insulating film 53.

  Such interlayer insulating films 51 and 53 are made of, for example, a silicon oxide film. The wiring 52 is made of a metal film such as an aluminum film, for example. However, the constituent material of each part is not particularly limited as long as the function can be exhibited.

  A second silicon nitride film 55 is disposed on the interlayer insulating film 53. In plan view of the substrate 2, the second silicon nitride film 55 is disposed so as to overlap (cover) at least part of the wiring 52. Such a second silicon nitride film 55 has a function of protecting the sensor unit 3 and the wiring 52 from moisture and dust.

  The interlayer insulating films 51 and 53 and the second silicon nitride film 55 are provided so as not to overlap with the diaphragm 21, respectively, and in the present embodiment, have a frame shape surrounding the periphery of the diaphragm 21 in plan view. ing.

  Further, a through hole penetrating the interlayer insulating film 53 and the second silicon nitride film 55 is provided, and a terminal electrically connected to the wiring 35 through the through hole on the second silicon nitride film 55. 54 is provided.

  The base substrate 4 is disposed so as to face the diaphragm 21 so as to form a pressure reference chamber S between the base substrate 4 and the diaphragm 21. Specifically, the base substrate 4 is bonded to the lower surface of the substrate 2 so as to close the opening of the recess 22. As such a base substrate 4, a silicon substrate, a glass substrate, a ceramic substrate etc. can be used, for example.

  The pressure reference chamber S is formed by hermetically sealing the concave portion 22 with such a base substrate 4. Therefore, it can be said that the pressure reference chamber S is located on the lower side of the diaphragm 21 (the side opposite to the pressure receiving surface). The pressure reference chamber S is preferably a vacuum (for example, about 10 Pa or less). Thereby, the pressure sensor 1 can be used as an “absolute pressure sensor” that detects a pressure with reference to a vacuum. Therefore, the pressure sensor 1 is highly convenient. However, the pressure reference chamber S may not be in a vacuum state. The present invention can also be applied to a differential pressure sensor or a gauge pressure sensor in which a pressure introduction port is formed in the base substrate 4 and the recess 22 is communicated with the outside.

  The configuration of the pressure sensor 1 has been briefly described above. Next, characteristic parts of the pressure sensor 1 will be described in detail. In the pressure sensor 1, the first silicon nitride film 29 is preferably a high-purity film, and in particular, even if hydrogen (H) is inevitably contained, a film having an extremely small amount is preferable. That is, the hydrogen (H) content of the first silicon nitride film 29 is preferably 10 atomic% or less. As described above, by setting the hydrogen content of the first silicon nitride film 29 to 10 atomic% or less, a denser first silicon nitride film 29 can be obtained. Therefore, pinholes are hardly generated, and the barrier function of the first silicon nitride film 29 can be further enhanced. Therefore, the sensor unit 3 can be more effectively protected from components such as moisture and gas. Further, the first silicon nitride film 29 can be made thinner by the denseness of the film. Therefore, for the reasons described above, a larger detection signal is obtained from the sensor unit 3, and the pressure detection sensitivity is further improved.

  The hydrogen content of the first silicon nitride film 29 is further preferably 6 atomic percent or less, and more preferably 4 atomic percent or less. Thereby, the effect mentioned above becomes more remarkable.

  Further, the thickness T1 of the first silicon nitride film 29 is not particularly limited, but as described above, for example, it is preferably 10 nm or more and 200 nm or less, and more preferably 10 nm or more and 50 nm or less. Thereby, the first silicon nitride film 29 can be made sufficiently thin while sufficiently exerting the barrier function. Therefore, the internal stress of the first silicon nitride film 29 can be reduced, and the diaphragm 21 can be prevented from being bent and deformed by a force other than the pressure to be detected. Therefore, more excellent pressure detection characteristics can be exhibited. Here, the reason why the first silicon nitride film 29 can be thinned as described above is that the hydrogen content is suppressed to 10 atomic% or less and the first silicon nitride film 29 is formed of a dense film.

  The method for forming the first silicon nitride film 29 is not particularly limited as long as the hydrogen content can be 10 atomic% or less. For example, low pressure CVD (LP-CVD) can be used. Low-pressure CVD is, for example, CVD performed by reducing the growth pressure to about 0.1 Torr or more and 30 Torr or less, and forming the first silicon nitride film 29 having a low hydrogen content and a good and uniform film quality. Can do. Note that the low pressure CVD is performed in an environment of, for example, 700 ° C. or more (specifically, about 780 ° C. according to low pressure CVD using ammonia and dichlorosilane gas). Thus, when the first silicon nitride film 29 is formed, since the wiring 52 made of a metal material such as aluminum is not formed, the wiring 52 is not damaged (for example, softened or disconnected due to melting). .

  Further, the method for forming the second silicon nitride film 55 is not particularly limited, and for example, plasma CVD can be used. According to plasma CVD, although the hydrogen content is higher than that of the aforementioned low pressure CVD, the second silicon nitride film 55 can be formed at a relatively low temperature. Therefore, as will be described later in the manufacturing method, it is possible to suppress the wiring 52 made of a metal wiring such as aluminum from receiving thermal damage (disconnection due to softening, melting, etc.). Note that plasma CVD is, for example, a method in which high-frequency power is applied to a chamber, a source gas is turned into plasma, and a film is grown at a relatively low temperature of about 250 ° C. to 400 ° C. and a reduced pressure of about 0.1 Torr to 30 Torr. It is.

  The hydrogen content of the first silicon nitride film 29 is preferably lower than the hydrogen content of the second silicon nitride film 55. Conversely, the hydrogen content of the second silicon nitride film 55 is preferably higher than the hydrogen content of the first silicon nitride film 29. Thus, by making the hydrogen content of the second silicon nitride film 55 higher than the hydrogen content of the first silicon nitride film 29, it becomes possible to form the film at a lower temperature, and the second silicon nitride film 55 is formed. It is possible to form a film more easily without damaging other portions (while keeping the damage small).

  Further, the hydrogen (H) content of the second silicon nitride film 55 is not particularly limited, but is preferably more than 10 atom% and not more than 20 atom%, more preferably more than 10 atom% and not more than 15 atom%. preferable. As a result, the second silicon nitride film 55 is formed which is relatively dense and hardly forms pinholes, although it does not reach the first silicon nitride film 29. Therefore, the barrier function of the second silicon nitride film 55 can be further enhanced. Therefore, the sensor unit 3 can be more effectively protected from moisture, gas, and the like.

  The thickness T2 of the second silicon nitride film 55 is preferably thicker than the thickness T1 of the first silicon nitride film 29. As described above, the second silicon nitride film 55 has a higher hydrogen content than the first silicon nitride film 29, and is inferior in barrier function against moisture, gas, and the like. Therefore, by making the second silicon nitride film 55 thicker than the first silicon nitride film 29, the barrier function of the second silicon nitride film 55 against moisture, gas, etc. can be enhanced. Since the second silicon nitride film 55 is not disposed on the diaphragm 21, it is necessary to reduce the film thickness in order to increase the output of the sensor unit 3 like the first silicon nitride film 29 as described above. There is no. In other words, even if the thickness of the second silicon nitride film 55 is increased, the pressure detection sensitivity of the pressure sensor 1 is hardly affected.

  The thickness T2 of the second silicon nitride film 55 is not particularly limited, but is preferably 0.3 μm or more and 3 μm or less, for example. Thereby, the effect mentioned above becomes more remarkable.

  The hydrogen content in the first silicon nitride film 29 and the second silicon nitride film 55 is, for example, using Rutherford Backscattering Spectrometry (RBS) or Hydrogen Forward Scattering (HFS). Can be measured.

  The configuration of the pressure sensor 1 has been described in detail above. The pressure sensor 1 as described above includes a diaphragm 21 that is bent and deformed by receiving pressure, a sensor unit 3 provided on the diaphragm 21, and a first silicon nitride film provided on the upper surface (one surface) side of the diaphragm 21. 29. The hydrogen (H) content of the first silicon nitride film 29 is 10 atomic% or less. Thereby, a denser first silicon nitride film 29 is obtained. Therefore, pinholes are hardly generated, and the barrier function of the first silicon nitride film 29 can be further enhanced. Therefore, the sensor unit 3 can be more effectively protected from moisture, gas, and the like, and reaction deterioration of the sensor unit 3 with moisture, gas, and the like can be suppressed. Therefore, the pressure sensor 1 is highly reliable. Further, the first silicon nitride film 29 can be made thinner by the denseness of the film. Therefore, a larger detection signal is obtained from the sensor unit 3, and the pressure detection accuracy is further improved.

  Further, the pressure sensor 1 has a wiring 52 electrically connected to the sensor unit 3 and a second silicon nitride film 55 covering at least a part of the wiring 52. Thereby, the wiring 52 can be protected from moisture or the like by the second silicon nitride film 55. The hydrogen (H) content of the first silicon nitride film 29 is preferably lower than the hydrogen content of the second silicon nitride film 55. Thereby, the barrier function of the first silicon nitride film 29 can be further enhanced. Also, the first silicon nitride film 29 and the second silicon nitride film 55 can be formed more easily.

  From another point of view, as described above, the pressure sensor 1 includes the diaphragm 21 that is bent and deformed by receiving pressure, the sensor unit 3 provided on the diaphragm 21, and the upper surface (one surface) side of the diaphragm 21. A first silicon nitride film 29 provided on the wiring portion 52, a wiring 52 electrically connected to the sensor unit 3, and a second silicon nitride film 55 covering at least a part of the wiring 52. The hydrogen content of the first silicon nitride film 29 is lower than the hydrogen content of the second silicon nitride film 55. Thereby, a denser first silicon nitride film 29 is obtained. Therefore, pinholes are hardly generated, and the barrier function of the first silicon nitride film 29 can be further enhanced. Therefore, the sensor unit 3 can be more effectively protected from moisture, gas, etc., and the pressure sensor 1 is highly reliable. Further, the first silicon nitride film 29 can be made thinner by the denseness of the film. Therefore, a larger detection signal is obtained from the sensor unit 3, and the pressure detection accuracy is further improved. Also, the first silicon nitride film 29 and the second silicon nitride film 55 can be formed more easily.

  Further, the hydrogen content of the first silicon nitride film 29 is preferably 10 atomic% or less. Thereby, the barrier function of the first silicon nitride film 29 can be further enhanced. Therefore, the sensor unit 3 can be more effectively protected from moisture, gas, and the like. Further, the first silicon nitride film 29 can be made thinner by the denseness of the film. Therefore, a larger detection signal is obtained from the sensor unit 3, and the pressure detection accuracy is further improved.

  Further, as described above, the pressure sensor 1 has the silicon oxide film 28 provided between the first silicon nitride film 29 and the diaphragm 21. Thereby, the interface state of the piezoresistive elements 31, 32, 33, and 34 can be reduced and the generation of noise can be suppressed. In particular, when the first silicon nitride film 29 is formed by low pressure CVD, the first silicon nitride film 29 having a relatively large internal stress may be obtained. The silicon oxide film 28 has a function of relieving the internal stress of the first silicon nitride film 29 and making it difficult to transmit the internal stress of the first silicon nitride film 29 to the diaphragm 21. Thereby, it can suppress that the diaphragm 21 bends and deform | transforms by force other than the pressure which is a detection target. Therefore, more excellent pressure detection characteristics can be exhibited.

  As described above, the thickness T1 of the first silicon nitride film 29 is preferably 200 nm or less. Thereby, the first silicon nitride film 29 can be made sufficiently thin while sufficiently exhibiting the barrier characteristics.

  Further, as described above, the thickness T2 of the second silicon nitride film 55 is preferably thicker than the thickness T1 of the first silicon nitride film 29. Thereby, the first silicon nitride film 29 can be thinned, and the pressure detection characteristic of the pressure sensor 1 can be improved. In addition, the second silicon nitride film 55 can be thickened, and the barrier function of the second silicon nitride film 55 can be enhanced.

  Further, as described above, the pressure sensor 1 has the pressure reference chamber S arranged on the lower surface (the other surface) side of the diaphragm 21. Thereby, the pressure received by the upper surface (pressure receiving surface) of the diaphragm 21 can be detected with the pressure in the pressure reference chamber S as a reference. Therefore, it is possible to detect the pressure with a relatively simple configuration and with high accuracy.

  Next, a manufacturing method of the pressure sensor 1 will be described. As shown in FIG. 4, the manufacturing method of the pressure sensor 1 includes a sensor part forming step, a first silicon nitride film forming step, a wiring forming step, a second silicon nitride film forming step, and a diaphragm forming step. Have.

[Sensor part formation process]
First, as shown in FIG. 5, a substrate 2 composed of an SOI substrate formed by laminating a first silicon layer 2a, a silicon oxide layer 2b, and a second silicon layer 2c is prepared. Next, for example, the surface of the second silicon layer 2c is thermally oxidized to form a silicon oxide film 28 on the upper surface of the substrate 2 as shown in FIG. Next, as shown in FIG. 7, the sensor unit 3 is formed on the upper surface of the substrate 2. The sensor unit 3 can be formed by doping (diffusing or injecting) impurities such as phosphorus and boron into the upper surface (second silicon layer 2c) of the substrate 2.

[First silicon nitride film forming step]
Next, as shown in FIG. 8, a first silicon nitride film 29 having a hydrogen content of 10 atomic% or less is formed on the silicon oxide film 28. The first silicon nitride film 29 has a lower hydrogen content than the second silicon nitride film 55 to be formed later. The first silicon nitride film 29 can be formed by, for example, low pressure CVD (LP-CVD). As a result, the first silicon nitride film 29 having a good and uniform film quality with a low hydrogen content can be formed. Note that the low-pressure CVD is performed in an environment of 700 ° C. or higher, for example, but at this point, the wiring 52 made of a metal material such as aluminum is not formed. Therefore, the wiring 52 does not receive damage (for example, disconnection due to softening or melting) by low pressure CVD.

[Wiring formation process]
Next, after patterning the silicon oxide film 28 and the first silicon nitride film 29 by using a photolithography technique and an etching technique, an interlayer insulating film 51, a wiring 52, and an interlayer insulating film are formed on the substrate 2 as shown in FIG. The film 53 is formed in order using a sputtering method, a CVD method, or the like. The interlayer insulating films 51 and 53 are made of, for example, a silicon oxide film, and the wiring 52 is made of, for example, a metal film such as an aluminum film. Further, the wiring 52 is patterned into a predetermined shape using, for example, a photolithography technique and an etching technique.

  At this time, the interlayer insulating film 51 and the interlayer insulating film 53 are also disposed on the portion 21 </ b> A that will later become the diaphragm 21.

[Second silicon nitride film forming step]
Next, as shown in FIG. 10, a second silicon nitride film 55 is formed on the interlayer insulating film 53. A method for manufacturing the second silicon nitride film 55 is not particularly limited, and for example, plasma CVD can be used. According to plasma CVD, the second silicon nitride film 55 can be formed at a relatively low temperature (for example, 400 ° C. or lower). Therefore, thermal damage (such as disconnection due to softening, melting, etc.) to the wiring 52 formed of metal wiring such as aluminum can be suppressed.

  Next, as shown in FIG. 11, the second silicon nitride film 55 on the portion 21A to be the diaphragm 21 later is removed by wet etching. According to wet etching, the etching selectivity between the second silicon nitride film 55 and the interlayer insulating film 53 can be increased relatively easily. Therefore, the interlayer insulating film 53 can be used as an etching stopper, and the second silicon nitride film 55 can be more reliably removed in this step. However, the second silicon nitride film 55 may be removed by dry etching.

  Next, as shown in FIG. 12, the interlayer insulating films 51 and 53 on the portion 21A to be the diaphragm 21 later are removed by wet etching. According to wet etching, the etching selectivity between the interlayer insulating films 51 and 53 and the first silicon nitride film 29 can be increased relatively easily. Therefore, in this step, the removal of the first silicon nitride film 29 together with the interlayer insulating films 51 and 53 can be effectively suppressed.

  Here, as described above, since the first silicon nitride film 29 is a dense film having a hydrogen content of 10 atomic% or less, the first silicon nitride film 29 has a high etching resistance with respect to a film having a higher hydrogen content, for example. It can be demonstrated. Therefore, removal of the first silicon nitride film 29 in this step can be more effectively suppressed. Further, as described above, since the first silicon nitride film 29 has a homogeneous film quality, there is almost no difference in the etching rate in each part. Therefore, in this step, even if a part of the first silicon nitride film 29 is removed, the first silicon nitride film 29 is unlikely to have a film thickness variation (that is, a place where it is removed excessively does not easily occur). Therefore, the first silicon nitride film 29 does not adversely affect the detection accuracy of the pressure sensor 1.

  Next, the terminals 54 are sequentially formed on the second silicon nitride film 55 by using a sputtering method, a CVD method, or the like.

[Diaphragm formation process]
Next, as shown in FIG. 13, a recess 22 is formed in the lower surface of the substrate 2 to obtain a diaphragm 21. The method for forming the recess 22 is not particularly limited, but can be formed by dry etching using a silicon deep etching apparatus as described above. In addition, this process is not limited to the said order, You may perform before a 2nd silicon nitride film formation process, specifically, for example, before a sensor part formation process.

  Next, as shown in FIG. 14, the base substrate 4 is bonded to the lower surface of the substrate 2 so as to close the opening of the recess 22 while the inside of the recess 22 is evacuated. Thereby, the pressure reference chamber S in a vacuum state is obtained. Thus, the pressure sensor 1 that can detect the absolute pressure is obtained.

  Such a method for manufacturing the pressure sensor 1 includes a step of forming the sensor unit 3 on the substrate 2, and a hydrogen (H) content of 10 atomic% or less on the upper surface (one surface) side of the substrate 2. It can be said that the method includes a step of disposing the silicon nitride film 29 and a step of forming the concave portion 22 on the lower surface (the other surface) side of the substrate 2 and forming the diaphragm 21 that is bent and deformed by receiving pressure. Thereby, a denser first silicon nitride film 29 having excellent barrier characteristics can be obtained, and the sensor unit 3 can be more effectively protected from moisture, gas, and the like. Therefore, a highly reliable pressure sensor 1 can be obtained.

  From another point of view, the manufacturing method of the pressure sensor 1 described above includes the step of forming the sensor portion 3 on the substrate 2 and the first silicon nitride film 29 on the upper surface (one surface) side of the substrate 2. A step of arranging the wiring 52 electrically connected to the sensor unit 3 on the upper surface (one surface) side of the substrate 2, and a second silicon nitride film 55 covering at least a part of the wiring 52. And a step of forming a concave portion 22 on the lower surface (the other surface) side of the substrate 2 and forming a diaphragm 21 that is bent and deformed by receiving pressure. The hydrogen (H) content of the obtained first silicon nitride film 29 is lower than the hydrogen content of the second silicon nitride film 55. Thereby, a denser first silicon nitride film 29 having excellent barrier characteristics can be obtained, and the sensor unit 3 can be more effectively protected from moisture, gas, and the like. Therefore, a highly reliable pressure sensor 1 can be obtained.

Second Embodiment
Next, a pressure sensor according to a second embodiment of the present invention will be described.

  FIG. 15 is a sectional view of a pressure sensor according to the second embodiment of the present invention. 16 to 18 are cross-sectional views for explaining a method of manufacturing the pressure sensor shown in FIG.

  Hereinafter, the pressure sensor according to the second embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.

  The pressure sensor according to the second embodiment of the present invention is substantially the same as the first embodiment described above except that the configuration of the second silicon nitride film 55 is different. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above.

  As shown in FIG. 15, in the pressure sensor 1 of this embodiment, the second silicon nitride film 55 is disposed so as to cover not only the upper surface of the interlayer insulating film 51 but also the inner surfaces of the interlayer insulating films 51 and 53. . Thereby, the penetration | invasion of the water | moisture content, gas, etc. to the interlayer insulation films 51 and 53 can be suppressed more effectively.

  Next, the manufacturing method of the pressure sensor 1 of this embodiment is demonstrated. As in the first embodiment described above, the manufacturing method of the pressure sensor 1 includes a sensor part forming step, a first silicon nitride film forming step, a wiring forming step, a second silicon nitride film forming step, and a diaphragm forming step. And have. The manufacturing method of the present embodiment is the same as the manufacturing method of the first embodiment except for the second silicon nitride film forming step. Therefore, only the second silicon nitride film forming process will be described below.

[Second silicon nitride film forming step]
First, as shown in FIG. 16, the interlayer insulating films 51 and 53 on the portion 21A to be the diaphragm 21 later are removed by wet etching. At this time, the first silicon nitride film 29 functions as an etching stopper.

  Next, as shown in FIG. 17, a second silicon nitride film 55 is formed on the substrate 2 and the interlayer insulating film 53. A method for manufacturing the second silicon nitride film 55 is not particularly limited, and for example, plasma CVD can be used. According to plasma CVD, since excellent step coverage can be exhibited, the second silicon nitride film 55 can be more reliably formed on the portion where the interlayer insulating films 51 and 53 are removed.

  Next, as shown in FIG. 18, the second silicon nitride film 55 on the portion 21A to be the diaphragm 21 later is removed by wet etching. The first silicon nitride film 29 is located immediately below the second silicon nitride film 55. Although the first and second silicon nitride films 29 and 55 are made of the same material but have different film forming methods, a sufficiently high etching selectivity can be ensured. Therefore, excessive removal of the first silicon nitride film 29 can be suppressed in this step.

  Also according to the second embodiment, the same effects as those of the first embodiment described above can be exhibited.

<Third Embodiment>
Next, a pressure sensor according to a third embodiment of the present invention will be described.

FIG. 19 is a cross-sectional view of a pressure sensor according to a third embodiment of the present invention.
Hereinafter, the pressure sensor according to the third embodiment will be described focusing on the differences from the above-described embodiment, and description of similar matters will be omitted.

  The pressure sensor according to the third embodiment of the present invention is substantially the same as the first embodiment described above except that the arrangement of the pressure reference chamber S is different. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above.

  As shown in FIG. 19, the pressure sensor 1 of the present embodiment has a pressure reference chamber S formed on the upper side of the diaphragm 21. Therefore, in accordance with this, in the pressure sensor 1 of the present embodiment, the base substrate 4 is omitted from the configuration of the first embodiment described above, but the periphery for forming the pressure reference chamber S on the substrate 2 is omitted. A structure 6 is provided.

  The surrounding structure 6 forms a pressure reference chamber S with the substrate 2. The surrounding structure 6 includes an interlayer insulating film 61 disposed on the substrate 2, a wiring layer 62 disposed on the interlayer insulating film 61, and an interlayer insulating film 63 disposed on the wiring layer 62 and the interlayer insulating film 61. A wiring layer 64 disposed on the interlayer insulating film 63, a second silicon nitride film 65 disposed on the wiring layer 64 and the interlayer insulating film 63, and a wiring layer 64 and the second silicon nitride film 65. And a sealing layer 66 formed.

  The wiring layer 62 includes a frame-shaped guard ring 621 disposed so as to surround the pressure reference chamber S, and a wiring 622 connected to the wiring 35 of the sensor unit 3. Similarly, the wiring layer 64 includes a frame-shaped guard ring 641 disposed so as to surround the pressure reference chamber S, and a wiring 642 connected to the wiring 622. The sensor unit 3 is pulled out to the upper surface of the surrounding structure 6 by these wirings 622 and 642 and connected to the terminal 54.

  The wiring layer 64 has a covering layer 644 that is located on the ceiling of the pressure reference chamber S and is integrally formed with the guard ring 641. In addition, a plurality of through holes 645 that communicate between the inside and outside of the pressure reference chamber S are disposed in the coating layer 644. The plurality of through holes 645 are holes for release etching when removing the sacrificial layer filling the pressure reference chamber S until the middle of manufacture. The guard rings 621 and 641 function as etching stoppers during the release etching.

  In addition, a sealing layer 66 is disposed on the covering layer 644, and the through hole 645 is sealed by the sealing layer 66 to form an airtight pressure reference chamber S.

  The second silicon nitride film 65 has a function of protecting the surrounding structure 6 from moisture, dust, scratches, and the like. Such a second silicon nitride film 65 is disposed on the interlayer insulating film 63 and the wiring layer 64 so as not to block the through hole 645 of the coating layer 644.

Among such surrounding structures 6, for example, an insulating film such as a silicon oxide film (SiO ₂ film) can be used as the interlayer insulating films 61 and 63. Further, as the wiring layers 62 and 64, for example, a metal film such as an aluminum film can be used. Further, as the sealing layer 66, for example, a metal film such as Al, Cu, W, Ti, or TiN, a silicon oxide film, or the like can be used.

  Also according to the third embodiment, the same effects as those of the first embodiment described above can be exhibited.

<Fourth embodiment>
Next, a pressure sensor according to a fourth embodiment of the present invention will be described.

FIG. 20 is a cross-sectional view of a pressure sensor according to the fourth embodiment of the present invention.
Hereinafter, the pressure sensor according to the fourth embodiment will be described with a focus on differences from the above-described embodiment, and description of similar matters will be omitted.

  The pressure sensor according to the fourth embodiment of the present invention is substantially the same as the first embodiment described above except that the pressure reference chamber S is not provided. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above.

  As shown in FIG. 20, in the pressure sensor 1 of the present embodiment, a through hole 41 communicating with the recess 22 is formed in the base substrate 4. And the pressure sensor 1 of this embodiment is arrange | positioned so that the upper surface and lower surface of the diaphragm 21 may be located in a mutually different space. Specifically, the upper surface of the diaphragm 21 is located in the space S2, and the lower surface of the diaphragm 21 is located in the space S3. According to such a configuration, the pressure sensor 1 can detect the pressure difference between the space S2 and the space S3. That is, the pressure sensor 1 can be used as a differential pressure sensor.

  According to the fourth embodiment, the same effect as that of the first embodiment described above can be exhibited.

<Fifth Embodiment>
Next, a pressure sensor module according to a fifth embodiment of the invention will be described.

  FIG. 21 is a sectional view of a pressure sensor module according to the fifth embodiment of the present invention. FIG. 22 is a plan view of a support substrate included in the pressure sensor module shown in FIG.

  Hereinafter, the pressure sensor module according to the fourth embodiment will be described with a focus on differences from the above-described embodiments, and description of similar matters will be omitted.

  As shown in FIG. 21, the pressure sensor module 100 includes a package 110 having an internal space S1, a support substrate 120 arranged to be drawn out of the package 110 from the internal space S1, and a support substrate in the internal space S1. The circuit element 130 and the pressure sensor 1 supported by 120, and the filling unit 140 disposed in the internal space S1 are included. According to such a pressure sensor module 100, the pressure sensor 1 can be protected by the package 110 and the filling unit 140. As the pressure sensor 1, for example, any one of the first, second, and third embodiments described above can be used.

  The package 110 includes a base 111 and a housing 112, and the base 111 and the housing 112 are joined to each other via an adhesive layer so as to sandwich the support substrate 120. The package 110 formed in this way has an opening 110a formed at the upper end portion thereof, and an internal space S1 communicating with the opening 110a.

  The constituent materials of the base 111 and the housing 112 are not particularly limited. For example, various ceramics such as oxide ceramics such as alumina, silica, titania and zirconia, and nitride ceramics such as silicon nitride, aluminum nitride and titanium nitride. Insulating materials such as various resin materials such as polyethylene, polyamide, polyimide, polycarbonate, acrylic resin, ABS resin, and epoxy resin can be used, and one or more of these can be used in combination. it can. Among these, it is particularly preferable to use various ceramics.

  Although the package 110 has been described above, the configuration of the package 110 is not particularly limited as long as the function can be exhibited.

  The support substrate 120 is sandwiched between the base 111 and the housing 112, and is arranged so as to be drawn out of the internal space S1 to the outside of the package 110. The support substrate 120 supports the circuit element 130 and the pressure sensor 1 and electrically connects the circuit element 130 and the pressure sensor 1. As shown in FIG. 22, such a support substrate 120 includes a flexible base material 121 and a plurality of wirings 129 arranged on the base material 121.

  The substrate 121 has a frame-like base portion 122 having an opening 122 a and a belt-like strip body 123 extending from the base portion 122. Then, the band body 123 extends outside the package 110 by being sandwiched between the base 111 and the housing 112 at the outer edge portion of the base portion 122. As such a substrate 121, for example, a commonly used flexible printed circuit board can be used. In addition, in this embodiment, although the base material 121 has flexibility, all or one part of the base material 121 may be hard.

  In a plan view of the substrate 121, the circuit element 130 and the pressure sensor 1 are located inside the opening 122a and arranged side by side. Further, the circuit element 130 and the pressure sensor 1 are respectively suspended from the base material 121 via the bonding wires BW and supported by the support substrate 120 in a state of floating from the support substrate 120. The circuit element 130 and the pressure sensor 1 are electrically connected via a bonding wire BW and a wiring 129, respectively. As described above, by supporting the circuit element 130 and the pressure sensor 1 in a floating state with respect to the support substrate 120, it becomes difficult for stress to be transmitted from the support substrate 120 to the circuit element 130 and the pressure sensor 1. Detection accuracy is improved.

  The circuit element 130 includes a drive circuit for supplying a voltage to the bridge circuit 30, a temperature compensation circuit for temperature compensating the output from the bridge circuit 30, a pressure detection circuit for obtaining a pressure received from the output from the temperature compensation circuit, An output circuit for converting the output from the pressure detection circuit into a predetermined output format (CMOS, LV-PECL, LVDS, etc.) and the like is provided.

  The filling unit 140 is disposed in the internal space S <b> 1 so as to cover the circuit element 130 and the pressure sensor 1. The filling unit 140 protects the circuit element 130 and the pressure sensor 1 (dustproof and waterproof), and external stress (for example, drop impact) acting on the pressure sensor 1 is not easily transmitted to the circuit element 130 and the pressure sensor 1. Become.

  Moreover, the filling part 140 can be comprised with a liquid or a gel-like filler, and is comprised especially with a gel-like filler in the point which can suppress the excessive displacement of the circuit element 130 and the pressure sensor 1. Is preferred. According to such a filling unit 140, the circuit element 130 and the pressure sensor 1 can be effectively protected from moisture, and the pressure can be efficiently transmitted to the pressure sensor 1. The filler constituting the filling unit 140 is not particularly limited, and for example, silicone oil, fluorine-based oil, silicone gel, or the like can be used.

  The pressure sensor module 100 has been described above. Such a pressure sensor module 100 includes a pressure sensor 1 and a package 110 that houses the pressure sensor 1. Therefore, the pressure sensor 1 can be protected by the package 110. Moreover, the effect of the pressure sensor 1 mentioned above can be enjoyed, high sensitivity and excellent reliability can be exhibited.

  In addition, as a structure of the pressure sensor module 100, it is not limited to the above-mentioned structure, For example, the filling part 140 may be abbreviate | omitted. In this embodiment, the pressure sensor 1 and the circuit element 130 are supported by the bonding wire BW while being suspended from the support substrate 120. For example, the pressure sensor 1 and the circuit element 130 are directly supported. It may be disposed on the substrate 120. Moreover, in this embodiment, although the pressure sensor 1 and the circuit element 130 are arrange | positioned side by side, the pressure sensor 1 and the circuit element 130 may be arrange | positioned along with the height direction, for example.

<Sixth Embodiment>
Next, an electronic apparatus according to a sixth embodiment of the invention will be described.

FIG. 23 is a perspective view showing an altimeter as an electronic apparatus according to the sixth embodiment of the present invention.
As shown in FIG. 23, an altimeter 200 as an electronic device can be worn on the wrist like a wristwatch. In addition, the pressure sensor 1 (pressure sensor module 100) is mounted inside the altimeter 200, and the altitude from the sea level of the current location, the atmospheric pressure of the current location, or the like can be displayed on the display unit 201. The display unit 201 can display various information such as the current time, the user's heart rate, and weather.

  An altimeter 200 as an example of such an electronic device has a pressure sensor 1. Therefore, the altimeter 200 can enjoy the effect of the pressure sensor 1 described above, and can exhibit high performance and high reliability.

<Seventh embodiment>
Next, an electronic apparatus according to a seventh embodiment of the invention will be described.

  FIG. 24 is a front view showing a navigation system as an electronic apparatus according to the seventh embodiment of the present invention.

  As shown in FIG. 24, a navigation system 300 as an electronic device includes map information (not shown), position information acquisition means from a GPS (Global Positioning System), a gyro sensor, an acceleration sensor, vehicle speed data, Self-contained navigation means, pressure sensor 1 (pressure sensor module 100), and display unit 301 for displaying predetermined position information or course information.

  According to the navigation system 300, altitude information can be acquired in addition to the acquired position information. For example, when driving on an elevated road that shows approximately the same position as that of a general road, if the navigation system does not have altitude information, the navigation system determines whether the vehicle is traveling on an ordinary road or an elevated road. It was not possible to provide the user with general road information as priority information. Therefore, by installing the pressure sensor 1 in the navigation system 300 and acquiring altitude information by the pressure sensor 1, it is possible to detect an altitude change due to entering the elevated road from a general road, and in the traveling state of the elevated road Navigation information can be provided to the user.

  A navigation system 300 as an example of such an electronic device includes the pressure sensor 1. Therefore, the navigation system 300 can enjoy the effect of the pressure sensor 1 described above, and can exhibit high performance and high reliability.

  The electronic device of the present invention is not limited to the altimeter and the navigation system described above. For example, a personal computer, a digital still camera, a mobile phone, a smartphone, a tablet terminal, a watch (including a smart watch), a drone, a medical device ( For example, it is applied to electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic devices, electronic endoscopes), various measuring instruments, instruments (for example, vehicles, aircraft, ship instruments), flight simulators, etc. be able to.

<Eighth Embodiment>
Next, a moving object according to an eighth embodiment of the invention will be described.

FIG. 25 is a perspective view showing an automobile as a moving body according to the eighth embodiment of the invention.
As shown in FIG. 25, an automobile 400 as a moving body has a vehicle body 401 and four wheels 402 (tires), and wheels 402 are driven by a power source (engine) (not shown) provided in the vehicle body 401. Is configured to rotate. Further, the automobile 400 has an electronic control unit (ECU) 403 mounted on the vehicle body 401, and the pressure sensor 1 is built in the electronic control unit 403. The electronic control unit 403 can grasp the moving state, the posture, and the like by the pressure sensor 1 detecting the acceleration, the inclination, and the like of the vehicle body 401, and can accurately control the wheels 402 and the like. Thereby, the automobile 400 can move safely and stably. The pressure sensor 1 may be mounted on a navigation system or the like provided in the automobile 400.

  An automobile 400 as an example of such a moving body has a pressure sensor 1. Therefore, the automobile 400 can enjoy the effect of the pressure sensor 1 described above, and can exhibit high performance and high reliability.

  As described above, the pressure sensor, the pressure sensor manufacturing method, the pressure sensor module, the electronic device, and the moving body of the present invention have been described based on the illustrated embodiments, but the present invention is not limited to these, The configuration can be replaced with any configuration having a similar function. In the above-described embodiment, the piezoresistive pressure sensor has been described. However, the embodiment can also be applied to a capacitive pressure sensor. Moreover, other arbitrary structures and processes may be added. Moreover, you may combine each embodiment suitably.

  DESCRIPTION OF SYMBOLS 1 ... Pressure sensor, 2 ... Board | substrate, 2a ... 1st silicon layer, 2b ... Silicon oxide layer, 2c ... 2nd silicon layer, 21 ... Diaphragm, 21A ... Part, 22 ... Recessed part, 28 ... Silicon oxide film, 29 ... 1st DESCRIPTION OF SYMBOLS 1 Silicon nitride film, 3 ... Sensor part, 30 ... Bridge circuit, 31, 32, 33, 34 ... Piezoresistive element, 35 ... Wiring, 4 ... Base substrate, 41 ... Through-hole, 51 ... Interlayer insulating film, 52 ... Wiring , 53 ... interlayer insulating film, 54 ... terminal, 55 ... second silicon nitride film, 6 ... surrounding structure, 61 ... interlayer insulating film, 62 ... wiring layer, 621 ... guard ring, 622 ... wiring, 63 ... interlayer insulating film 64 ... wiring layer, 641 ... guard ring, 642 ... wiring, 644 ... coating layer, 645 ... through hole, 65 ... second silicon nitride film, 66 ... sealing layer, 100 ... pressure sensor module, 110 ... package DESCRIPTION OF SYMBOLS 110a ... Opening, 111 ... Base, 112 ... Housing, 120 ... Support substrate, 121 ... Base material, 122 ... Base, 122a ... Opening, 123 ... Band, 129 ... Wiring, 130 ... Circuit element, 140 ... Filling part, 200 Altimeter, 201 ... display unit, 300 ... navigation system, 301 ... display unit, 400 ... automobile, 401 ... vehicle body, 402 ... wheel, 403 ... electronic control unit, BW ... bonding wire, S ... pressure reference chamber, S1 ... inside Space, S2, S3 ... Space

Claims (13)

A diaphragm that bends and deforms under pressure,
A sensor provided in the diaphragm;
A first silicon nitride film provided on one surface side of the diaphragm,
The pressure sensor according to claim 1, wherein a hydrogen content of the first silicon nitride film is 10 atomic% or less. Wiring electrically connected to the sensor unit;
The pressure sensor according to claim 1, further comprising: a second silicon nitride film that covers at least a part of the wiring. A diaphragm that bends and deforms under pressure,
A sensor provided in the diaphragm;
A first silicon nitride film provided on one surface side of the diaphragm;
Wiring electrically connected to the sensor unit;
A second silicon nitride film covering at least a part of the wiring,
The pressure sensor according to claim 1, wherein a hydrogen content of the first silicon nitride film is lower than a hydrogen content of the second silicon nitride film.   The pressure sensor according to claim 3, wherein the hydrogen content of the first silicon nitride film is 10 atomic% or less.   5. The pressure sensor according to claim 1, further comprising a silicon oxide film provided between the first silicon nitride film and the diaphragm. 6.   The pressure sensor according to claim 1, wherein the first silicon nitride film has a thickness of 200 nm or less.   5. The pressure sensor according to claim 2, wherein a thickness of the second silicon nitride film is thicker than a thickness of the first silicon nitride film. 6.   The pressure sensor according to claim 1, further comprising a pressure reference chamber disposed on the other surface side of the diaphragm. Forming a sensor portion on the substrate;
Disposing a first silicon nitride film having a hydrogen content of 10 atomic% or less on one surface side of the substrate;
Forming a recess on the other surface side of the substrate, and forming a diaphragm that bends and deforms by receiving pressure. Forming a sensor portion on the substrate;
Disposing a first silicon nitride film on one surface side of the substrate;
Arranging a wiring electrically connected to the sensor unit on one surface side of the substrate;
Disposing a second silicon nitride film covering at least part of the wiring;
Forming a recess on the other surface side of the substrate, and forming a diaphragm that bends and deforms under pressure.
The method of manufacturing a pressure sensor, wherein a hydrogen content of the first silicon nitride film is lower than a hydrogen content of the second silicon nitride film. A pressure sensor according to any one of claims 1 to 8,
A pressure sensor module comprising: a package housing the pressure sensor.   An electronic apparatus comprising the pressure sensor according to claim 1.   A moving body comprising the pressure sensor according to claim 1.

Images