JP2016138794A - Electronic device, method for manufacturing electronic device, pressure sensor, vibrator, altimeter, electronic apparatus, and mobile body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic device with which it is possible to effectively reduce the collapse of a ceiling part and a method for manufacturing the electronic device, and to provide a pressure sensor, a vibrator, an altimeter, an electronic apparatus, and a mobile body equipped with the electronic device.SOLUTION: A physical quantity sensor 1 according to the present invention comprises a board 2, piezoresistive elements 5 disposed on one surface side of the board 2, a wall part disposed on the one surface side of the board 2 in a manner of enclosing the piezoresistive element 5 in a plan view of the board 2, and a ceiling part disposed on the wall part opposite the board 2 and constituting a cavity part S together with the board 2 and the wall part, the ceiling part having a coating layer 641 including metal, and a TiN layer 648 disposed on the coating layer 641 opposite the cavity part S, the thermal expansion coefficient of the TiN layer being smaller than the coating layer 641.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic device, an electronic device manufacturing method, a pressure sensor, a vibrator, an altimeter, an electronic apparatus, and a moving object.

  An electronic device having a cavity formed by using a semiconductor manufacturing process is known (for example, see Patent Document 1). As an example of such an electronic device, for example, an electric component described in Patent Document 1 can be cited. As described in Patent Document 1, the electrical component includes a substrate, a functional element formed on the substrate, a cavity for housing the functional element on the substrate, and a plurality of through holes. And a second layer formed on the first layer and blocking the plurality of through holes of the first layer.

In addition, in the electric component described in Patent Document 1, the first layer is formed on the first film (SiO ₂ film) formed on the lower side and the first film, and has a smaller thermal expansion coefficient than the first film. A second film (SiN film). Accordingly, the first layer has a structure that swells to the upper side, prevents contact between the first layer and the functional element, and improves reliability.

However, in the electric component described in Patent Document 1, since the combination of the first film and the second film is the SiO ₂ film and the SiN film, the difference between these linear expansion coefficients is small, and the bulge of the first layer is not sufficient. The first layer may be crushed.

JP 2012-045656 A

  An object of the present invention is to provide an electronic device capable of effectively reducing crushing of a ceiling portion and a manufacturing method thereof, and a pressure sensor, a vibrator, an altimeter, an electronic apparatus, and a moving body including the electronic device. Is to provide.

Such an object is achieved by the present invention described below.
[Application Example 1]
An electronic device of the present invention includes a substrate,
A wall portion annularly arranged on one surface side of the substrate in a plan view of the substrate;
A ceiling portion that is disposed on the opposite side of the substrate with respect to the wall portion and constitutes an internal space together with the substrate and the wall portion;
With
The ceiling part is
A first layer comprising a metal;
A second layer disposed on a side opposite to the internal space with respect to the first layer and having a smaller coefficient of thermal expansion than the first layer;
It is characterized by having.

  According to such an electronic device, since the thermal expansion coefficient of the first layer is larger than that of the second layer, the ceiling portion is placed on the side (outside) opposite to the internal space using the difference in thermal expansion coefficient of these layers. It can be bent into a dome shape. Thereby, crushing of a ceiling part can be reduced. In particular, since the first layer contains metal, the coefficient of thermal expansion of the first layer can be increased, and accordingly, the difference in coefficient of thermal expansion between the first layer and the second layer can be increased. . Therefore, the ceiling portion can be sufficiently bent outward, and as a result, collapse of the ceiling portion can be effectively reduced.

[Application Example 2]
In the electronic device of the present invention, the second layer preferably contains a metal compound.

  Thereby, the thermal expansion coefficient of a 2nd layer can be made small and the thermal expansion coefficient difference of a 1st layer and a 2nd layer can be enlarged in connection with it.

[Application Example 3]
In the electronic device of the present invention, it is preferable that the second layer contains titanium nitride.

  Thus, the thermal expansion coefficient of the second layer can be reduced, and the second layer can be formed by using the antireflection film when the first layer is patterned using the photolithography method.

[Application Example 4]
In the electronic device of the present invention, the first layer preferably contains aluminum.

  Thereby, the thermal expansion coefficient of the first layer can be increased. Aluminum has a high affinity with the semiconductor manufacturing process, and the first layer can be formed easily and with high accuracy.

[Application Example 5]
In the electronic device according to the aspect of the invention, it is preferable that the first layer and the wall portion include the same material.

  Thereby, a 1st layer and a wall part can be formed collectively, and a manufacturing process can be simplified.

[Application Example 6]
In the electronic device according to the aspect of the invention, it is preferable that the electronic device includes a third layer that is disposed on the opposite side to the internal space with respect to the second layer and has a smaller coefficient of thermal expansion than the second layer.

  Thereby, a ceiling part can fully bend outside using the thermal expansion coefficient difference of a 1st layer and a 2nd layer, and a 3rd layer.

[Application Example 7]
In the electronic device of the present invention, the third layer preferably contains silicon oxide or silicon nitride.

  Both silicon oxide and silicon nitride have a very low coefficient of thermal expansion. Therefore, when the third layer contains silicon oxide or silicon nitride, the difference in thermal expansion coefficient between the first layer, the second layer, and the third layer can be increased.

[Application Example 8]
In the electronic device of the present invention, the substrate is
It is preferable that a sensor element that outputs an electric signal due to strain is provided, and a diaphragm portion that is provided at a position overlapping the ceiling portion in a plan view and bends and deforms due to pressure reception.

  Thereby, an electronic device (physical quantity sensor) capable of detecting pressure can be realized.

[Application Example 9]
An electronic device manufacturing method of the present invention is an electronic device manufacturing method of the present invention,
A first step of forming the first layer using a sputtering method;
A second step of forming the second layer using a sputtering method;
It is characterized by having.

  According to such a method for manufacturing an electronic device, a dome-shaped ceiling portion that bends outward can be formed. In addition, by using the sputtering method, the film formation temperature in the second step can be easily made lower than the film formation temperature in the first step, so that the ceiling can be efficiently expanded. Moreover, since using the sputtering method is superior in productivity to using the CVD method, an electronic device can be produced at a low cost.

[Application Example 10]
In the method for manufacturing an electronic device of the present invention, the second step is preferably performed at a temperature lower than that of the first step.

  Thereby, in the obtained electronic device, distortion can be effectively generated between the first layer and the second layer so that the ceiling portion bends outward.

[Application Example 11]
The pressure sensor of the present invention includes the electronic device of the present invention.

  Thereby, the crushing of a ceiling part can be reduced effectively and the pressure sensor which has the outstanding reliability can be provided.

[Application Example 12]
A vibrator according to the present invention includes the electronic device according to the present invention.

  As a result, it is possible to effectively reduce the crushing of the ceiling and provide a vibrator having excellent reliability.

[Application Example 13]
An altimeter according to the present invention includes the electronic device according to the present invention.

  Thereby, the crushing of a ceiling part can be reduced effectively and the altimeter which has the outstanding reliability can be provided.

[Application Example 14]
An electronic apparatus according to the present invention includes the electronic device according to the present invention.

  Thereby, the crushing of a ceiling part can be reduced effectively and the electronic device which has the outstanding reliability can be provided.

[Application Example 15]
The moving body of the present invention includes the electronic device of the present invention.

  Thereby, the crushing of a ceiling part can be reduced effectively and the mobile body which has the outstanding reliability can be provided.

It is sectional drawing which shows the electronic device (physical quantity sensor) which concerns on 1st Embodiment of this invention. It is a top view which shows arrangement | positioning of the piezoresistive element (functional element) of the electronic device shown in FIG. It is a figure for demonstrating the effect | action of the electronic device shown in FIG. 1, Comprising: (a) is sectional drawing which shows a pressurization state, (b) is a top view which shows a pressurization state. It is a partial expanded sectional view of the electronic device shown in FIG. It is a figure which shows the manufacturing process of the electronic device shown in FIG. It is a figure which shows the manufacturing process of the electronic device shown in FIG. It is sectional drawing which shows the electronic device (physical quantity sensor) which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the electronic device (vibrator) which concerns on 3rd Embodiment of this invention. It is a figure for demonstrating the resonator (functional element) with which the electronic device shown in FIG. 8 is provided, Comprising: (a) is sectional drawing, (b) is a top view. It is sectional drawing which shows an example of the pressure sensor of this invention. It is a perspective view which shows an example of the altimeter of this invention. It is a front view which shows an example of the electronic device of this invention. It is a perspective view which shows an example of the moving body of this invention.

  Hereinafter, an electronic device, a manufacturing method of an electronic device, a pressure sensor, a vibrator, an altimeter, an electronic apparatus, and a moving body of the present invention will be described in detail based on each embodiment shown in the accompanying drawings.

1. Electronic Device <First Embodiment>
FIG. 1 is a cross-sectional view showing an electronic device (physical quantity sensor) according to a first embodiment of the present invention. FIG. 2 is a plan view showing an arrangement of piezoresistive elements (functional elements) of the electronic device shown in FIG. 3A and 3B are diagrams for explaining the operation of the electronic device shown in FIG. 1, wherein FIG. 3A is a cross-sectional view showing a pressurized state, and FIG. 3B is a plan view showing the pressurized state. is there. In the following, for convenience of explanation, the upper side in FIG. 1 is referred to as “upper” and the lower side is referred to as “lower”.

  A physical quantity sensor 1 (electronic device) shown in FIG. 1 includes a substrate 2 having a diaphragm section 20, a plurality of piezoresistive elements 5 (functional elements) that are functional elements arranged in the diaphragm section 20, and a cavity together with the substrate 2. The laminated structure 6 which forms the part S (internal space), and the level | step difference formation layer 3 arrange | positioned between the board | substrate 2 and the laminated structure 6 are provided.

Hereinafter, each part which comprises the physical quantity sensor 1 is demonstrated sequentially.
-Board-
The substrate 2 includes a semiconductor substrate 21, an insulating film 22 provided on one surface of the semiconductor substrate 21, and an insulating film 23 provided on the surface of the insulating film 22 opposite to the semiconductor substrate 21. Have.

  The semiconductor substrate 21 includes a silicon layer 211 (handle layer) made of single crystal silicon, a silicon oxide layer 212 (box layer) made of a silicon oxide film, and a silicon layer made of single crystal silicon. 213 (device layer) is an SOI substrate laminated in this order. The semiconductor substrate 21 is not limited to the SOI substrate, and may be another semiconductor substrate such as a single crystal silicon substrate.

  The insulating film 22 is, for example, a silicon oxide film and has an insulating property. Further, the insulating film 23 is, for example, a silicon nitride film, and has an insulation property and resistance to an etching solution containing hydrofluoric acid. Here, since the insulating film 22 (silicon oxide film) is interposed between the semiconductor substrate 21 (silicon layer 213) and the insulating film 23 (silicon nitride film), the stress generated when the insulating film 23 is formed. Is transmitted to the semiconductor substrate 21 by the insulating film 22. The insulating film 22 can also be used as an inter-element isolation film when a semiconductor circuit is formed on and above the semiconductor substrate 21. Note that the insulating films 22 and 23 are not limited to the above-described constituent materials, and any one of the insulating films 22 and 23 may be omitted as necessary.

  A patterned step forming layer 3 is disposed on the insulating film 23 of the substrate 2. The step forming layer 3 is formed so as to surround the periphery of the diaphragm portion 20 in a plan view, and is between the upper surface of the step forming layer 3 and the upper surface of the substrate 2 and on the center side (inner side) of the diaphragm portion 20. ) To form a step portion corresponding to the thickness of the step forming layer 3. Thereby, when the diaphragm part 20 bends and deform | transforms by receiving pressure, stress can be concentrated on the boundary part between the level | step-difference parts of the diaphragm part 20. FIG. Therefore, the detection sensitivity can be improved by disposing the piezoresistive element 5 at the boundary portion (or the vicinity thereof).

  The step forming layer 3 is made of, for example, single crystal silicon, polycrystalline silicon (polysilicon), or amorphous silicon. Further, the step forming layer 3 may be configured by doping (diffusing or implanting) impurities such as phosphorus and boron into single crystal silicon, polycrystalline silicon (polysilicon), or amorphous silicon, for example. In this case, since the step forming layer 3 has conductivity, for example, when a MOS transistor is formed on the substrate 2 outside the cavity S, a part of the step forming layer 3 is used as the gate electrode of the MOS transistor. Can do. A part of the step forming layer 3 can also be used as a wiring.

  Such a substrate 2 is provided with a diaphragm portion 20 which is thinner than the surrounding portion and is bent and deformed by receiving pressure. The diaphragm portion 20 is formed by providing a bottomed recess 24 on the lower surface of the semiconductor substrate 21. That is, the diaphragm portion 20 is configured to include the bottom portion of the concave portion 24 opened on one surface of the substrate 2. The diaphragm 20 has a pressure receiving surface 25 on the lower surface. In the present embodiment, as shown in FIG. 2, the diaphragm portion 20 has a square (rectangular) plan view shape.

  In the substrate 2 of the present embodiment, the recess 24 penetrates the silicon layer 211, and the diaphragm portion 20 is composed of four layers of a silicon oxide layer 212, a silicon layer 213, an insulating film 22, and an insulating film 23. Here, as will be described later, the silicon oxide layer 212 can be used as an etching stop layer when the recess 24 is formed by etching in the manufacturing process of the physical quantity sensor 1, and the thickness of the diaphragm portion 20 for each product. Variations can be reduced.

  The concave portion 24 may not penetrate the silicon layer 211, and the diaphragm portion 20 may be constituted by five layers of the thin portion of the silicon layer 211, the silicon oxide layer 212, the silicon layer 213, the insulating film 22, and the insulating film 23. .

-Piezoresistive element (functional element)-
As shown in FIG. 1, the plurality of piezoresistive elements 5 are respectively formed on the cavity portion S side of the diaphragm portion 20. Here, the piezoresistive element 5 is formed in the silicon layer 213 of the semiconductor substrate 21.

  As shown in FIG. 2, the plurality of piezoresistive elements 5 are composed of a plurality of piezoresistive elements 5 a, 5 b, 5 c, and 5 d disposed on the outer periphery of the diaphragm portion 20.

  The piezoresistive element 5a, the piezoresistive element 5b, and the piezoresistor respectively correspond to the four sides of the diaphragm portion 20 that form a quadrangle when viewed from the thickness direction of the substrate 2 (hereinafter simply referred to as “planar view”). An element 5c and a piezoresistive element 5d are arranged.

  The piezoresistive element 5 a extends along a direction perpendicular to the corresponding side of the diaphragm portion 20. A pair of wirings 214a is electrically connected to both ends of the piezoresistive element 5a. Similarly, the piezoresistive element 5 b extends along a direction perpendicular to the corresponding side of the diaphragm portion 20. A pair of wirings 214b is electrically connected to both ends of the piezoresistive element 5b.

  On the other hand, the piezoresistive element 5 c extends along a direction parallel to the corresponding side of the diaphragm portion 20. A pair of wirings 214c is electrically connected to both ends of the piezoresistive element 5c. Similarly, the piezoresistive element 5 d extends along a direction parallel to the corresponding side of the diaphragm portion 20. A pair of wirings 214d is electrically connected to both ends of the piezoresistive element 5d.

  Hereinafter, the wirings 214a, 214b, 214c, and 214d are collectively referred to as “wiring 214”.

  The piezoresistive element 5 and the wiring 214 are each made of silicon (single crystal silicon) doped (diffused or implanted) with impurities such as phosphorus and boron. Here, the impurity doping concentration in the wiring 214 is higher than the impurity doping concentration in the piezoresistive element 5. Note that the wiring 214 may be made of metal.

  Further, the plurality of piezoresistive elements 5 are configured such that, for example, resistance values in a natural state are equal to each other.

  The piezoresistive element 5 as described above constitutes a bridge circuit (Wheatstone bridge circuit) via the wiring 214 and the like. A driving circuit (not shown) that supplies a driving voltage is connected to the bridge circuit. In this bridge circuit, a voltage corresponding to the resistance value of the piezoresistive element 5 is output as a detection signal.

-Laminated structure-
The laminated structure 6 is formed so as to define a cavity S between itself and the substrate 2 described above. Here, the laminated structure 6 is disposed on the piezoresistive element 5 side of the diaphragm portion 20, and defines (configures) the cavity portion S (internal space) together with the diaphragm portion 20 (or the substrate 2).

  The laminated structure 6 includes an interlayer insulating film 61 formed on the substrate 2 so as to surround the piezoresistive element 5 in plan view, a wiring layer 62 formed on the interlayer insulating film 61, a wiring layer 62, and an interlayer An interlayer insulating film 63 formed on the insulating film 61; a wiring layer 64 formed on the interlayer insulating film 63 and having a coating layer 641 having a plurality of pores 642 (openings) and a TiN layer 648; The surface protective film 65 formed on the layer 64 and the interlayer insulating film 63 and the sealing layer 66 provided on the covering layer 641 are provided.

  The interlayer insulating films 61 and 63 are each composed of, for example, a silicon oxide film. The wiring layers 62 and 64 and the sealing layer 66 are each made of a metal such as aluminum. Further, the sealing layer 66 seals the pores 642 included in the coating layer 641. The surface protective film 65 is a silicon nitride film, for example.

  In such a laminated structure 6, the structure including the wiring layer 62 and the wiring layer 64 excluding the covering layer 641 and the TiN layer 648 surrounds the piezoresistive element 5 in a plan view on one surface side of the substrate 2. It constitutes the “wall part” arranged in In addition, the structure including the covering layer 641, the TiN layer 648, and the sealing layer 66 is disposed on the opposite side of the substrate 2 from the wall, and the cavity S (internal space) is defined as the substrate 2 and the wall. It constitutes the “ceiling” that is configured together with the above. The covering layer 641 is a “first layer” containing a metal. The TiN layer 648 is a “second layer” that is disposed on the opposite side of the cavity S from the coating layer 641 and has a smaller coefficient of thermal expansion than the coating layer 641. In addition, a wall part, a ceiling part, and the matter relevant to these are explained in full detail behind.

  Moreover, such a laminated structure 6 can be formed using a semiconductor manufacturing process such as a CMOS process. Note that a semiconductor circuit may be formed on and above the silicon layer 213. This semiconductor circuit has active elements such as MOS transistors, and other circuit elements such as capacitors, inductors, resistors, diodes, and wires (including wires connected to the piezoresistive element 5) formed as necessary. ing.

  The cavity S defined by the substrate 2 and the laminated structure 6 is a sealed space. The cavity S functions as a pressure reference chamber that serves as a reference value for the pressure detected by the physical quantity sensor 1. In this embodiment, the cavity S is in a vacuum state (300 Pa or less). By making the cavity S into a vacuum state, the physical quantity sensor 1 can be used as an “absolute pressure sensor” that detects pressure based on the vacuum state, and the convenience is improved.

However, the cavity S may not be in a vacuum state, may be atmospheric pressure, may be in a reduced pressure state where the atmospheric pressure is lower than atmospheric pressure, or is a pressurized state where the atmospheric pressure is higher than atmospheric pressure. It may be. The cavity S may be filled with an inert gas such as nitrogen gas or a rare gas.
The configuration of the physical quantity sensor 1 has been briefly described above.

  As shown in FIG. 3A, the physical quantity sensor 1 having such a configuration deforms the diaphragm portion 20 in accordance with the pressure P received by the pressure receiving surface 25 of the diaphragm portion 20, and as a result, FIG. As shown, the piezoresistive elements 5a, 5b, 5c and 5d are distorted, and the resistance values of the piezoresistive elements 5a, 5b, 5c and 5d change. Accordingly, the output of the bridge circuit formed by the piezoresistive elements 5a, 5b, 5c, and 5d changes, and the magnitude of the pressure received by the pressure receiving surface 25 can be obtained based on the output.

  More specifically, in the natural state before the deformation of the diaphragm portion 20 as described above, for example, when the resistance values of the piezoresistive elements 5a, 5b, 5c, 5d are equal to each other, the piezoresistive elements 5a, 5b Is equal to the product of the resistance values of the piezoresistive elements 5c and 5d, and the output (potential difference) of the bridge circuit is zero.

  On the other hand, when the deformation of the diaphragm portion 20 as described above occurs, compressive strain along the longitudinal direction and tensile strain along the width direction are generated in the piezoresistive elements 5a and 5b as shown in FIG. At the same time, tensile strain along the longitudinal direction and compressive strain along the width direction are generated in the piezoresistive elements 5c and 5d. Therefore, when the deformation of the diaphragm portion 20 as described above occurs, one of the resistance values of the piezoresistive elements 5a and 5b and the piezoresistive elements 5c and 5d increases, and the other resistance. The value decreases.

  Due to the distortion of the piezoresistive elements 5a, 5b, 5c, and 5d, a difference between the product of the resistance values of the piezoresistive elements 5a and 5b and the product of the resistance values of the piezoresistive elements 5c and 5d occurs. The output (potential difference) is output from the bridge circuit. Based on the output from the bridge circuit, the magnitude (absolute pressure) of the pressure received by the pressure receiving surface 25 can be obtained.

  Here, when the deformation of the diaphragm portion 20 as described above occurs, one of the resistance values of the piezoresistive elements 5a and 5b and the resistance values of the piezoresistive elements 5c and 5d increases. Since the resistance value decreases, the change in the difference between the product of the resistance values of the piezoresistive elements 5a and 5b and the product of the resistance values of the piezoresistive elements 5c and 5d can be increased. The output can be increased. As a result, the pressure detection sensitivity can be increased.

  As described above, in the physical quantity sensor 1, the diaphragm portion 20 included in the substrate 2 is provided at a position overlapping the coating layer 641 in a plan view, and is deformed by receiving pressure. Thereby, the physical quantity sensor 1 capable of detecting the pressure can be realized. Further, since the piezoresistive element 5 disposed in the diaphragm unit 20 is a sensor element that outputs an electric signal due to distortion, the pressure detection sensitivity can be improved.

(Wall and ceiling)
Hereinafter, a wall part and a ceiling part are explained in full detail.
FIG. 4 is a partially enlarged cross-sectional view of the electronic device shown in FIG.

  As described above, the covering layer 641 (first layer), the TiN layer 648 (second layer), and the sealing layer 66 constitute a “ceiling part”, and this ceiling part is opposite to the cavity part S. It bends (swells) into a dome shape. Thereby, crushing of a ceiling part can be reduced. Here, the coating layer 641 contains a metal, and the TiN layer 648 is disposed on the side opposite to the cavity S with respect to the coating layer 641, and the coefficient of thermal expansion (in the in-plane direction) is higher than that of the coating layer 641. (Linear expansion coefficient) is small. Thereby, the ceiling part can be bent to the opposite side (outside) from the cavity part S using the difference in coefficient of thermal expansion between the coating layer 641 and the TiN layer 648 to form a dome shape. In particular, since the coating layer 641 contains a metal, the thermal expansion coefficient of the coating layer 641 can be increased, and accordingly, the difference in thermal expansion coefficient between the coating layer 641 and the TiN layer 648 can be increased. . Therefore, the ceiling portion can be sufficiently bent outward (largely), and as a result, collapse of the ceiling portion can be effectively reduced.

Hereinafter, each part which comprises a wall part and a ceiling part is demonstrated in detail.
As shown in FIG. 4, the wiring layer 62 includes a Ti layer 622 made of titanium (Ti), a TiN layer 623 made of titanium nitride (TiN), and an Al layer 624 made of aluminum (Al). And a TiN layer 625 made of titanium nitride (TiN), which are laminated in this order. Similarly, the wiring layer 64 includes a Ti layer 645 made of titanium (Ti), a TiN layer 646 made of titanium nitride (TiN), an Al layer 647 made of aluminum (Al), and titanium nitride. And a TiN layer 648 made of (TiN), which are laminated in this order. The surface protective film 65 includes a silicon oxide film 652 and a silicon nitride film 653, and these are stacked in this order.

  Here, the covering layer 641 is composed of an Al layer 647. Thus, when the coating layer 641 contains aluminum, the thermal expansion coefficient of the coating layer 641 can be increased. Aluminum has a high affinity with the semiconductor manufacturing process, and the first layer can be formed easily and with high accuracy.

  Further, as described above, the structure including the wiring layer 62 and the wiring layer 64 excluding the covering layer 641 and the TiN layer 648 is disposed on one surface side of the substrate 2 so as to surround the piezoresistive element 5 in plan view. It constitutes a “wall”. The Al layer 647 constitutes the coating layer 641 and part of the wall. Therefore, the covering layer 641 and the wall portion contain the same material. Thereby, the coating layer 641 (first layer) and the wall portion can be formed in a lump, and the manufacturing process can be simplified.

  The constituent material of the coating layer 641 is not limited to aluminum as long as it includes a single metal, and for example, various metals having high affinity with the semiconductor manufacturing process can be used.

  In addition, the metal compound generally has an extremely low coefficient of thermal expansion compared to a metal. Therefore, when the TiN layer 648 contains a metal compound (titanium nitride), the thermal expansion coefficient of the TiN layer 648 can be reduced, and accordingly, the difference in thermal expansion coefficient between the coating layer 641 and the TiN layer 648 can be increased. it can. In addition, the TiN layer 648 can be formed using an antireflection film when the coating layer 641 is patterned using a photolithography method.

  The constituent material of the second layer is not limited to titanium nitride as long as it has a smaller coefficient of thermal expansion (linear expansion coefficient in the plane direction) than the constituent material of the coating layer 641. A compound (metal nitride, metal oxide, metal oxynitride, or the like) can be used.

  Further, the thickness of the TiN layer 648 (second layer) is determined according to the thickness of the coating layer 641, the constituent material, and the like, and is not particularly limited, but is preferably 300 to 2000 mm, more preferably 500 to 1500 mm. More preferably, it is more preferably 800 to 1200. Accordingly, the ceiling portion can be efficiently expanded by utilizing the difference in thermal expansion coefficient between the coating layer 641 and the TiN layer 648 while ensuring good productivity. On the other hand, if the thickness of the TiN layer 648 is too thin, depending on the thickness of the covering layer 641, the constituent material, etc., the ceiling portion is sufficiently expanded using the difference in thermal expansion coefficient between the covering layer 641 and the TiN layer 648. It may not be possible. On the other hand, if the thickness of the TiN layer 648 is too thick, it may take a long time for film formation, or unnecessary stress may be applied to other parts (for example, the diaphragm portion 20).

(Electronic device manufacturing method)
Next, a method for manufacturing the physical quantity sensor 1 will be briefly described.

  5 and 6 are diagrams showing manufacturing steps of the electronic device shown in FIG. Hereinafter, a method for manufacturing the physical quantity sensor 1 will be described with reference to these drawings.

[Element formation process]
First, as shown in FIG. 5A, a semiconductor substrate 21 which is an SOI substrate is prepared.

  Then, by doping (ion implantation) impurities such as phosphorus (n-type) or boron (p-type) into the silicon layer 213 of the semiconductor substrate 21, a plurality of piezoresistive elements 5 are obtained as shown in FIG. And the wiring 214 is formed.

For example, when ion implantation of boron is performed at +80 keV, the ion implantation concentration into the piezoresistive element 5 is set to about 1 × 10 ¹⁴ atoms / cm ² . Further, the concentration of ion implantation into the wiring 214 is made larger than that of the piezoresistive element 5. For example, when boron is ion-implanted at 10 keV, the ion implantation concentration into the wiring 214 is set to about 5 × 10 ¹⁵ atoms / cm ² . Further, after the ion implantation as described above, for example, annealing is performed at about 1000 ° C. for about 20 minutes.

[Insulating film forming process]
Next, as illustrated in FIG. 5C, the insulating film 22, the insulating film 23, and the step forming layer 3 are formed in this order on the silicon layer 213.

  The insulating films 22 and 23 can be formed by, for example, a sputtering method, a CVD method, or the like. The step forming layer 3 is formed, for example, by depositing polycrystalline silicon by a sputtering method, a CVD method, or the like, and then doping (ion-implanting) an impurity such as phosphorus or boron as necessary, followed by patterning by etching. By doing so, it can be formed.

[Interlayer insulation film / wiring layer formation process]
Next, as shown in FIG. 5D, a sacrificial layer 41, a wiring layer 62, a sacrificial layer 42, and a wiring layer 64 are formed in this order on the insulating film 23.

  The sacrificial layers 41 and 42 are partly removed by a cavity forming step to be described later, and the remaining portions become the interlayer insulating films 61 and 63. The sacrificial layers 41 and 42 are formed by forming a silicon oxide film by sputtering, CVD, or the like, and patterning the silicon oxide film by etching.

  The thicknesses of the sacrificial layers 41 and 42 are not particularly limited, but are, for example, about 1500 nm to 5000 nm.

  The wiring layers 62 and 64 are formed by patterning after forming a layer made of aluminum, for example, by sputtering or CVD. Although not shown, when forming the wiring layer 62 having the Ti layer 622, the TiN layer 623, the Al layer 624 and the TiN layer 625, the Ti layer and the TiN layer are formed uniformly in this order, and then these The Ti layer 622 and the TiN layer 623 are formed by patterning the layers, and then the Al layer and the TiN layer 625 are formed uniformly in this order, and then the Al layer 624 and the TiN layer 625 are formed by patterning these layers. Form. Here, the TiN layer 623 has a function of improving the wettability of Al in order to improve the Al filling property in the through hole of the sacrificial layer 41, and the Ti layer 622 includes the TiN layer 623 and the sacrificial layer 41. It has a function to improve the adhesion. The TiN layer uniformly formed on the Al layer functions as an antireflection film for preventing reflection of exposure light of photolithography when the Al layer 624 and the TiN layer 625 are formed by patterning. Similarly, the wiring layer 64 can also be formed.

  Here, the coating layer 641 and the TiN layer 648 after film formation are placed at a temperature lower than the temperature at the time of film formation, and a stress that tends to contract in the surface direction is generated. At this time, since the thermal expansion coefficient of the coating layer 641 is larger than that of the TiN layer 648 as described above, the coating layer 641 tends to contract more than TiN. However, at this stage, the lower surface of the covering layer 641 is bonded to the sacrificial layer 42, and the shrinkage of these layers is regulated (restricted).

  The Al layer 647 and the TiN layer 648 are preferably formed using a sputtering method. Thus, the film formation temperature in the step of forming the TiN layer 648 (second step) can be easily made lower than the film formation temperature of the step of forming the Al layer 647 (first step), and will be described later. In this process, the ceiling portion can be efficiently expanded using the difference in thermal expansion coefficient between the coating layer 641 and the TiN layer 648. Further, unnecessary deposits in the cavity S can be reduced as compared with the case where the CVD method is used. As a result, the physical quantity sensor 1 having excellent reliability can be obtained.

  Further, the step of forming the TiN layer 648 (second step) is preferably performed at a lower temperature than the step of forming the Al layer 647 (first step). That is, the deposition temperature of the covering layer 641 (Al layer 647) is preferably higher than the deposition temperature of the TiN layer 648. Thereby, the stress difference between the coating layer 641 and the TiN layer 648 as described above can be increased. As a result, in the obtained physical quantity sensor 1, distortion can be effectively generated between the coating layer 641 and the TiN layer 648 so that the ceiling portion bends outward. Moreover, the specific film formation temperature of the coating layer 641 is preferably, for example, 200 ° C. or more and 500 ° C. or less, and more preferably 250 ° C. or more and 450 ° C. or less. Further, the specific film formation temperature of the TiN layer 648 is preferably, for example, 80 ° C. or higher and 170 ° C. or lower, and more preferably 100 ° C. or higher and 150 ° C. or lower.

  The thicknesses of the wiring layers 62 and 64 are not particularly limited, but are, for example, about 300 nm to 900 nm.

  Such a laminated structure composed of the sacrificial layers 41 and 42 and the wiring layers 62 and 64 is formed using a normal CMOS process, and the number of laminated layers is appropriately set as necessary. That is, more sacrificial layers and wiring layers may be stacked as necessary.

[Cavity formation process]
Next, by removing a part of the sacrificial layers 41 and 42, a cavity S (cavity) is formed between the insulating film 23 and the covering layer 641, as shown in FIG. 6 (e). Thereby, interlayer insulating films 61 and 63 are formed.

  When a part of the sacrificial layers 41 and 42 is removed in this way, the coating layer 641 and the TiN layer 648 are deformed so as to expand outward due to the stress caused by the difference in thermal expansion coefficient between the coating layer 641 and the TiN layer 648 described above. . The stress (internal stress) generated in the coating layer 641 and the TiN layer 648 is due to the crystal grain boundary of each layer (intrinsic stress) in addition to the above-mentioned difference in thermal expansion coefficient (thermal stress). This can also contribute to the expansion of the ceiling.

  The cavity S is formed by removing a part of the sacrificial layers 41 and 42 by etching through the plurality of pores 642 formed in the coating layer 641. Here, when wet etching is used as such etching, an etching solution such as hydrofluoric acid or buffered hydrofluoric acid is supplied from the plurality of pores 642, and when dry etching is used, hydrofluoric acid gas or the like is supplied from the plurality of pores 642. Etching gas is supplied. In such etching, the insulating film 23 functions as an etching stop layer. In addition, since the insulating film 23 has resistance to the etching solution, the function of protecting the components below the insulating film 23 (for example, the insulating film 22, the piezoresistive element 5, the wiring 214, etc.) from the etching solution. It also has.

  Here, before the etching, the surface protective film 65 is formed by sputtering, CVD, or the like. Thereby, the part used as the interlayer insulation films 61 and 62 of the sacrificial layers 41 and 42 can be protected in the case of this etching. The constituent material of the surface protective film 65 includes, for example, a silicon oxide film, a silicon nitride film, a polyimide film, an epoxy resin film, etc. having resistance to protect the element from moisture, dust, scratches, etc. A silicon nitride film is preferable. Although not shown, when the surface protective film 65 having the silicon oxide film 652 and the silicon nitride film 653 is formed, the silicon oxide film and the silicon nitride film are uniformly formed in this order, and then these layers are patterned. To form. Although the thickness of the surface protective film 65 is not specifically limited, For example, it is about 500 nm or more and 2000 nm or less.

[Sealing process]
Next, as shown in FIG. 6F, a sealing layer 66 made of a silicon oxide film, a silicon nitride film, a metal film such as Al, Cu, W, Ti, TiN, or the like is formed on the coating layer 641 by a sputtering method. The pores 642 are sealed by a CVD method or the like. Thus, the cavity S is sealed with the sealing layer 66, and the laminated structure 6 is obtained.

  Here, the deposition temperature of the sealing layer 66 is preferably lower than the deposition temperature of the covering layer 641 (Al layer 647), and the deposition temperature of the covering layer 641 (Al layer 647) and the TiN layer 648 are formed. More preferably, it is lower than both film temperatures. Thereby, in the obtained physical quantity sensor 1, distortion can be effectively generated between the coating layer 641 and the TiN layer 648 so that the ceiling portion is bent outward. The specific film formation temperature of the sealing layer 66 is, for example, preferably 80 ° C. or higher and 170 ° C. or lower, and more preferably 100 ° C. or higher and 150 ° C. or lower.

  When the sputtering method is used, unnecessary deposits in the internal space can be reduced as compared with the case where the CVD method is used. As a result, an electronic device having excellent reliability can be obtained.

  Further, the thickness of the sealing layer 66 is not particularly limited, but is, for example, about 1000 nm to 5000 nm.

[Diaphragm formation process]
Next, after grinding the lower surface of the silicon layer 211 as necessary, a part of the lower surface of the silicon layer 211 is removed (processed) by etching to form a recess 24 as shown in FIG. To do. Thereby, the diaphragm part 20 which opposes the coating layer 641 through the cavity part S is formed.

  Here, when part of the lower surface of the silicon layer 211 is removed, the silicon oxide layer 212 functions as an etching stop layer. Thereby, the thickness of the diaphragm part 20 can be prescribed | regulated with high precision.

Note that a method for removing a part of the lower surface of the silicon layer 211 may be dry etching, wet etching, or the like.
The physical quantity sensor 1 can be manufactured through the processes as described above.

  According to the manufacturing method of the physical quantity sensor 1 as described above, a dome-shaped ceiling portion that bends outward can be formed. Further, by using the sputtering method, the deposition temperature of the TiN layer 648 can be easily lowered than the deposition temperature of the coating layer 641, and thus the ceiling portion can be efficiently expanded. Moreover, since using the sputtering method is superior in productivity to using the CVD method, an electronic device can be produced at a low cost.

Second Embodiment
Next, a second embodiment of the present invention will be described.

  FIG. 7 is a sectional view showing an electronic device (physical quantity sensor) according to the second embodiment of the present invention.

Hereinafter, although 2nd Embodiment of this invention is described, it demonstrates centering around difference with embodiment mentioned above, The description of the same matter is abbreviate | omitted.
The present embodiment is the same as the first embodiment described above except that the configuration of the ceiling portion is different.

  The physical quantity sensor 1A (electronic device) shown in FIG. 7 is the same as the physical quantity sensor 1 of the first embodiment described above except that the layer 67 is provided on the sealing layer 66.

  The layer 67 is a “third layer” that is disposed on the opposite side of the cavity S from the TiN layer 648 and has a smaller coefficient of thermal expansion than the TiN layer 648. By providing such a third layer, the ceiling portion can be sufficiently bent outward using the thermal expansion coefficient difference between the covering layer 641 (Al layer 647) and the TiN layer 648 and the layer 67.

The constituent material of the layer 67 may be any material having a smaller coefficient of thermal expansion than the TiN layer 648, but is preferably silicon oxide (SiO ₂ ) or silicon nitride (SiN). Both silicon oxide and silicon nitride have a very low coefficient of thermal expansion. Therefore, when the layer 67 contains silicon oxide or silicon nitride, the thermal expansion coefficient difference between the coating layer 641 and the TiN layer 648 and the layer 67 can be increased.

  According to the second embodiment as described above, the collapse of the ceiling can be effectively reduced.

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

  FIG. 8 is a cross-sectional view showing an electronic device (vibrator) according to the third embodiment of the present invention. 9A and 9B are diagrams for explaining a resonator (functional element) included in the electronic device shown in FIG. 8, in which FIG. 9A is a cross-sectional view and FIG. 9B is a plan view.

  Hereinafter, the third embodiment of the present invention will be described. The description will focus on differences from the above-described embodiment, and description of similar matters will be omitted.

  The present embodiment is the same as the first embodiment described above except that the electronic device of the present invention is applied to a vibrator.

  An electronic device 1B shown in FIG. 8 is the same as the physical quantity sensor 1 of the first embodiment described above except that the substrate 2B and the resonator 5B (functional element) are provided instead of the substrate 2 and the piezoresistive element 5. It is configured. That is, the electronic device 1B includes a substrate 2B, a resonator 5B that is a functional element disposed on the substrate 2B, a laminated structure 6 that forms a cavity S (internal space) together with the substrate 2B, and a substrate 2B. And a step forming layer 3 disposed between the laminated structure 6 and the laminated structure 6.

  Here, the substrate 2B includes a semiconductor substrate 21B, an insulating film 22 provided on one surface of the semiconductor substrate 21B, and an insulating film 23 provided on the surface of the insulating film 22 opposite to the semiconductor substrate 21B. And have.

  The semiconductor substrate 21B is a flat plate, for example, a silicon single crystal substrate. Note that an SOI substrate may be used as the semiconductor substrate 21B.

  The resonator 5B includes four lower electrodes 51, a lower electrode 52, and an upper electrode 53 supported by the lower electrode 52.

  The four lower electrodes 51 (fixed electrodes) are two lower electrodes 51a and 51b arranged in a first direction (left and right direction in FIG. 9B) across the lower electrode 52 in plan view, It consists of two lower electrodes 51c and 51d arranged along a second direction (vertical direction in FIG. 9B) perpendicular to the first direction across the lower electrode 52. In addition, the four lower electrodes 51 are respectively arranged away from the lower electrode 52 in plan view.

  The two lower electrodes 51a and 51b are electrically connected to each other via a wiring (not shown) and are configured to have the same potential. Similarly, the two lower electrodes 51c and 51d are electrically connected to each other via a wiring (not shown) and are configured to have the same potential.

  The upper electrode 53 (vibrating body) includes four movable portions 531 (movable electrodes), a fixed portion 532 fixed to the lower electrode 52, and a connecting portion 533 that connects each movable portion 531 and the fixed portion 532. And have.

  The four movable parts 531 are provided corresponding to the four lower electrodes 51 described above, and each movable part 531 is opposed to the corresponding lower electrode 51 with an interval. That is, the four movable parts 531 sandwich two fixed parts 532 with two movable parts 531a and 531b arranged along the first direction (left and right direction in FIG. 9B) with the fixed part 532 interposed therebetween. It consists of two movable parts 531c and 531d arranged along a second direction (vertical direction in FIG. 9B) orthogonal to the first direction.

  The lower electrodes 51 and 52 and the upper electrode 53 are configured by doping (diffusing or implanting) impurities such as phosphorus and boron into single crystal silicon, polycrystalline silicon (polysilicon), or amorphous silicon, respectively. Have conductivity. The lower electrodes 51 and 52 can be formed together with the step forming layer 3.

  In the electronic device 1B configured as described above, a first voltage (alternating voltage) that periodically changes is applied between the lower electrodes 51a and 51b and the upper electrode 53, and the lower electrodes 51c and 51d and the upper electrode are applied. A second voltage similar to the first voltage is applied except that the phase is shifted by 180 ° between the first voltage and the third voltage.

  Then, the movable parts 531a and 531b are alternately displaced in the direction approaching and separating from the lower electrodes 51a and 51b and bend and vibrate, and the movable parts 531a and 531b have a phase opposite to that of the movable parts 531c and 531b. 531d is alternately displaced in the direction approaching and separating from the lower electrodes 51c and 51d, and bends and vibrates. That is, when the movable parts 531a and 531b are displaced in the direction approaching the lower electrodes 51a and 51b, the movable parts 531c and 531d are displaced in the direction away from the lower electrodes 51c and 51d, while the movable parts 531a and 531b are movable. When the parts 531a and 531b are displaced in a direction away from the lower electrodes 51a and 51b, the movable parts 531c and 531d are displaced in a direction approaching the lower electrodes 51c and 51d.

  In this way, by vibrating the movable parts 531a and 531b and the movable parts 531c and 531d in opposite phases, vibrations transmitted from the movable parts 531a and 531b to the fixed part 532 and vibrations transmitted from the movable parts 531c and 531d to the fixed part 532 are obtained. Can be offset each other. As a result, these vibrations leak to the outside through the fixed portion 532, so-called vibration leakage can be reduced, and the vibration efficiency of the electronic device 1B can be increased. As described above, the electronic device 1B can reduce vibration leakage from the movable portion 531 to the outside because the number of the movable portions 531 is plural.

  Such an electronic device 1B can be used, for example, as an oscillator that extracts a signal of a predetermined frequency by combining with an oscillation circuit (drive circuit). Such an oscillation circuit can be provided as a semiconductor circuit on the substrate 2B.

  According to the third embodiment as described above, the collapse of the ceiling can be effectively reduced.

2. Next, a pressure sensor (a pressure sensor of the present invention) including the physical quantity sensor of the present invention will be described. FIG. 10 is a cross-sectional view showing an example of the pressure sensor of the present invention.

  As shown in FIG. 10, the pressure sensor 100 of the present invention includes a physical quantity sensor 1, a casing 101 that houses the physical quantity sensor 1, and a calculation unit 102 that calculates a signal obtained from the physical quantity sensor 1 to pressure data. ing. The physical quantity sensor 1 is electrically connected to the calculation unit 102 via the wiring 103.

  The physical quantity sensor 1 is fixed to the inside of the housing 101 by fixing means (not shown). Further, the housing 101 has a through-hole 104 through which the diaphragm unit 20 of the physical quantity sensor 1 communicates with, for example, the atmosphere (outside the housing 101).

  According to such a pressure sensor 100, the diaphragm portion 20 receives pressure through the through hole 104. The pressure-received signal is transmitted to the calculation unit via the wiring 103, and pressure data is calculated. The calculated pressure data can be displayed via a display unit (not shown) (for example, a monitor of a personal computer).

3. Next, an example of an altimeter (the altimeter of the present invention) including the physical quantity sensor of the present invention will be described. FIG. 11 is a perspective view showing an example of an altimeter according to the present invention.

  The altimeter 200 can be worn on the wrist like a wristwatch. In addition, the physical quantity sensor 1 (pressure sensor 100) is mounted inside the altimeter 200, and the altitude from the current location above sea level, the atmospheric pressure at 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.

4). Next, a navigation system to which an electronic device including the physical quantity sensor of the present invention is applied will be described. FIG. 12 is a front view showing an example of an electronic apparatus of the present invention.

  The navigation system 300 includes map information (not shown), position information acquisition means from GPS (Global Positioning System), self-contained navigation means using a gyro sensor, acceleration sensor, and vehicle speed data, physical quantity sensor 1, The display unit 301 displays predetermined position information or course information.

  According to this navigation system, altitude information can be acquired in addition to the acquired position information. By obtaining altitude information, for example, when traveling on an elevated road that shows approximately the same position as a general road, if you do not have altitude information, you are traveling on an ordinary road or on an elevated road The navigation system was unable to determine whether or not the vehicle was being used, and the general road information was provided to the user as priority information. Therefore, in the navigation system 300 according to the present embodiment, altitude information can be acquired by the physical quantity sensor 1, and a change in altitude due to entering from an ordinary road to an elevated road is detected, and navigation information in the traveling state of the elevated road is obtained. Can be provided to the user.

  The display unit 301 is configured to be small and thin, such as a liquid crystal panel display or an organic EL (Organic Electro-Luminescence) display.

  The electronic device provided with the physical quantity sensor of the present invention is not limited to the above-described ones. For example, a personal computer, a mobile phone, a medical device (for example, an electronic thermometer, a blood pressure meter, a blood glucose meter, an electrocardiogram measuring device, an ultrasonic diagnostic device) , Electronic endoscope), various measuring instruments, instruments (for example, vehicles, aircraft, ship instruments), flight simulators, and the like.

5. Next, the moving body (the moving body of the present invention) to which the physical quantity sensor of the present invention is applied will be described. FIG. 13 is a perspective view showing an example of the moving body of the present invention.

  As shown in FIG. 13, the moving body 400 includes a vehicle body 401 and four wheels 402, and is configured to rotate the wheels 402 by a power source (engine) (not shown) provided in the vehicle body 401. ing. Such a moving body 400 incorporates a navigation system 300 (physical quantity sensor 1).

  As described above, the electronic device, pressure sensor, vibrator, altimeter, electronic device, and moving body of the present invention have been described based on the illustrated embodiments, but the present invention is not limited thereto, and the configuration of each part is as follows. It can be replaced with any configuration having a similar function. Moreover, other arbitrary components may be added.

  Moreover, although the number of piezoresistive elements (functional elements) provided in one diaphragm portion has been described as an example in the above-described embodiment, it is not limited to this. For example, one or more three The number may be 5 or less. Further, the arrangement, shape, and the like of the piezoresistive element are not limited to the above-described embodiment. For example, in the above-described embodiment, the piezoresistive element may be arranged at the center of the diaphragm portion.

  In the above-described embodiment, the case where a piezoresistive element is used as a sensor element for detecting the deflection of the diaphragm portion has been described as an example. However, such an element is not limited to this, for example, a resonator. Also good.

  In the above-described embodiment, the case where the resonator included in the vibrator has a plurality of movable parts has been described. However, the number of movable parts is not limited to this, but one or more, three or less, or five. It may be the above.

  In addition, the electronic device of the present invention is not limited to the physical quantity sensor and the vibrator described above, and as described above, the wall portion and the ceiling portion are formed on the substrate using the semiconductor manufacturing process, and the substrate, the wall portion, and the ceiling portion are formed. Thus, the present invention can be applied to various electronic devices that form an internal space.

1. Physical quantity sensor 1A ... Physical quantity sensor 1B ... Electronic device 2 ... Substrate 2B ... Substrate 3 ... Step formation layer 5 ... Piezoresistive element 5B ... Resonator 5a ... Piezoresistive element 5b ... Piezo Resistive element 5c ... Piezoresistive element 5d ... Piezoresistive element 6 ... Multilayer structure 20 ... Diaphragm part 21 ... Semiconductor substrate 21B ... Semiconductor substrate 22 ... Insulating film 23 ... Insulating film 24 ... Recess 25 · · · Pressure-receiving surface 41 · · · Sacrificial layer 42 · · · Sacrificial layer 51 · · · Lower electrode 51a · · · Lower electrode 51c · · · Lower electrode 51d · · · Lower electrode 52 · · · Lower electrode 53 · · · Upper electrode 61 Interlayer insulating film 62 Wiring layer 63 Interlayer insulating film 64 Wiring layer 65 Surface protective film 66 Sealing layer 67 Layer 100 Pressure sensor 101 Case 102 Calculation unit 103. Wiring 104 ... Through hole 200 ... Altimeter 201 ... Display 211 ... Silicon layer 212 ... Silicon oxide layer 213 ... Silicon layer 214 ... Wiring 214a ... Wiring 214b ... Wiring 214c ... Wiring 214d ... Wiring 300 ··· Navigation system 301 ··· Display unit 400 ··· Moving body 401 ··· Vehicle body 402 ··· Wheel 531 ··· Movable portion 531a ··· movable portion 531b ··· movable portion 531c ··· movable portion 531d · · · · · Fixing portion 533 · · · Connection portion 622 · · · Ti layer 623 · · · TiN layer 624 · · · Al layer 625 · · · TiN layer 641 · · · Coating layer 642 · · · Pore 645 · · · Ti layer 646 · · · TiN layer 647 ... Al layer 648 ... TiN layer 652 ... Silicon oxide film 653 ... Silicon nitride film S ... Cavity P ... Pressure

Claims (15)

A substrate,
A wall portion annularly arranged on one surface side of the substrate in a plan view of the substrate;
A ceiling portion that is disposed on the opposite side of the substrate with respect to the wall portion and constitutes an internal space together with the substrate and the wall portion;
With
The ceiling part is
A first layer comprising a metal;
A second layer disposed on a side opposite to the internal space with respect to the first layer and having a smaller coefficient of thermal expansion than the first layer;
An electronic device comprising:   The electronic device according to claim 1, wherein the second layer includes a metal compound.   The electronic device according to claim 2, wherein the second layer includes titanium nitride.   The electronic device according to claim 1, wherein the first layer contains aluminum.   The electronic device according to claim 1, wherein the first layer and the wall portion include the same material.   6. The electronic device according to claim 1, further comprising a third layer disposed on a side opposite to the internal space with respect to the second layer and having a smaller coefficient of thermal expansion than the second layer. .   The electronic device according to claim 3, wherein the third layer includes silicon oxide or silicon nitride. The substrate is
5. The electronic device according to claim 1, further comprising a diaphragm element that includes a sensor element that outputs an electric signal due to strain, is provided at a position overlapping the ceiling part in a plan view, and is bent and deformed by pressure reception. . A method for manufacturing an electronic device according to any one of claims 1 to 8,
A first step of forming the first layer using a sputtering method;
A second step of forming the second layer using a sputtering method;
A method for manufacturing an electronic device, comprising:   The method for manufacturing an electronic device according to claim 9, wherein the second step is performed at a temperature lower than that of the first step.   A pressure sensor comprising the electronic device according to claim 1.   A vibrator comprising the electronic device according to claim 1.   An altimeter comprising the electronic device according to claim 1.   An electronic apparatus comprising the electronic device according to claim 1.   A moving body comprising the electronic device according to claim 1.

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