JP3629185B2 - Semiconductor sensor and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor sensor for detecting a physical quantity applied to a diaphragm formed on a semiconductor substrate and a method for manufacturing the same.
[0002]
[Prior art]
As a conventional semiconductor pressure sensor, for example, there is one as shown in FIG. 12 (for example, JP 2000-2610 A).
In FIG. 12, an insulating film 18 is formed on the back surface of the Si substrate 1, an etching solution is injected from a small opening 24 provided on the insulating film 18, and the Si substrate 1 is etched to form a cavity 6. To do.
[0003]
And there exists a system which seals the cavity part 6 by sealing the small opening part 24 with the sealing part 23, and forms the reference | standard pressure chamber and the diaphragm part 10. FIG.
[0004]
In addition, 11 is a piezoresistor, 12 is a surface insulating layer, 13 is a metal wiring.
[0005]
Another example of the semiconductor pressure sensor is shown in FIG. 13 (for example, Japanese Patent Application Laid-Open No. 11-284204).
In FIG. 13, a sacrificial layer is formed on the Si substrate 1, a polycrystalline silicon layer is deposited on the sacrificial layer, and the movable electrode 22 is formed. Thereafter, there is a method of forming the pressure reference chamber and the diaphragm portion by etching away the sacrificial layer from the opening portion 24 and sealing the opening portion 24 with the sealing portion 23.
Reference numeral 19 denotes a fixed electrode, 20 denotes a polycrystalline insulating film, and 21 denotes a scaffold.
[0006]
[Problems to be solved by the invention]
However, the conventional semiconductor pressure sensor as shown in FIG. 12 has a problem that the process of forming the diaphragm portion and the reference pressure chamber is complicated and requires a lot of cost.
[0007]
Further, in the conventional semiconductor pressure sensor as shown in FIG. 13, since the insulating film 20 is made of polycrystalline silicon, a structurally unstable substance such as polycrystalline silicon must be used for the diaphragm portion, and the residual stress. There is a problem that it is difficult to control the film warpage due to this, and it is difficult to improve the accuracy of pressure measurement.
[0008]
An object of the present invention is to realize a semiconductor sensor capable of reducing costs, having high mechanical strength, and capable of measuring with high accuracy, and a manufacturing method thereof.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
(1) In a semiconductor sensor that converts a mechanical displacement amount into an electrical signal, a plurality of grooves or holes are formed in a predetermined region of the semiconductor substrate, and the semiconductor substrate in which the plurality of grooves or holes are formed is heat-treated, A cavity region is formed in the semiconductor substrate in the region where the plurality of grooves or holes are formed.
[0010]
(2) In the semiconductor pressure sensor, a plurality of grooves or holes are formed in a predetermined region of the semiconductor substrate, the semiconductor substrate on which the plurality of grooves or holes are formed is heat-treated, and the plurality of grooves or A cavity region is formed in the region where the hole is formed, and this cavity region is used as a pressure chamber. A part of the wall portion of the pressure chamber is used as a diaphragm portion, and the pressure is measured by displacement of the diaphragm portion.
[0011]
(3) In the semiconductor acceleration sensor, a plurality of grooves or holes are formed in a predetermined region of the semiconductor substrate, the semiconductor substrate on which the plurality of grooves or holes are formed is heat-treated, and the plurality of grooves or A hollow region is formed in the region where the hole is formed, a part of the wall portion of the hollow region is used as a diaphragm portion, and a movable electrode is formed in the diaphragm portion by etching the diaphragm portion. Detect acceleration.
[0012]
(4) In the semiconductor airflow sensor, a plurality of grooves or holes are formed in a predetermined region of the semiconductor substrate, the semiconductor substrate on which the plurality of grooves or holes are formed is heat-treated, and the plurality of grooves in the semiconductor substrate Alternatively, a cavity region is formed in a region where a hole is formed, a part of the wall portion of the cavity region is used as a diaphragm portion, and a heating resistor is formed on the diaphragm portion.
[0013]
(5) Preferably, in the above (1), (2), and (3), the corner of the hollow region is rounded with a radius of 0.3 μm or more.
[0014]
(6) Preferably, in the above (1), (2), and (3), the peripheral portion forming the cavity region is made of the same single crystal material.
[0015]
(7) Preferably, in the above (1), a part of the wall portion forming the hollow region is a first diaphragm, and a scaffold part to be fixed is provided on the first diaphragm. A second diaphragm was formed that displaced in response to the change.
[0016]
(8) In a semiconductor sensor manufacturing method for converting a mechanical displacement amount into an electrical signal, a step of forming a plurality of grooves or holes in a predetermined region of the semiconductor substrate, and a semiconductor substrate having the plurality of grooves or holes formed therein And a step of forming a cavity region in the region where the plurality of grooves or holes are formed in the semiconductor substrate.
[0017]
(9) In the method of manufacturing a semiconductor pressure sensor, a step of forming a plurality of grooves or holes in a predetermined region of the semiconductor substrate, and heat-treating the semiconductor substrate on which the plurality of grooves or holes are formed, Forming a cavity region in the region where the plurality of grooves or holes are formed, making the cavity region a pressure chamber, and making a part of the wall portion of the pressure chamber a diaphragm portion.
[0018]
(10) In the method of manufacturing a semiconductor acceleration sensor, a step of forming a plurality of grooves or holes in a predetermined region of the semiconductor substrate, and heat-treating the semiconductor substrate having the plurality of grooves or holes formed therein, A step of forming a hollow region in a region where the plurality of grooves or holes are formed, and forming a part of a wall portion of the hollow region as a diaphragm portion, and etching the diaphragm portion to form a movable electrode in the diaphragm portion A process.
[0019]
(11) In the method for manufacturing a semiconductor airflow sensor, a step of forming a plurality of grooves or holes in a predetermined region of the semiconductor substrate, and heat-treating the semiconductor substrate having the plurality of grooves or holes formed therein, Forming a cavity region in the region where the plurality of grooves or holes are formed, and forming a part of the wall portion of the cavity region as a diaphragm portion, and forming a heating resistor on the diaphragm portion. .
[0020]
A plurality of grooves or holes are formed in a predetermined region of the semiconductor substrate, and the semiconductor substrate in which the plurality of grooves or holes are formed is heat-treated, whereby a cavity region is formed in the region where the plurality of grooves or holes are formed in the semiconductor substrate. Is formed, and the thin film portion on the cavity portion is configured as a diaphragm portion.
[0021]
With the above configuration, the cavity region serving as the reference pressure chamber and the diaphragm portion can be formed at the same time using a normal Si wafer processing step, and the manufacturing process can be simplified.
[0022]
In the manufacturing method of the present invention, the diaphragm portion can be made of single crystal silicon made of the same material as that of the substrate, and the corner portion of the cavity portion for forming the diaphragm portion has a rounded shape. . For this reason, it is possible to form a diaphragm having high mechanical strength without stress being concentrated on the diaphragm support portion.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1-3 is explanatory drawing of the semiconductor pressure sensor which is the 1st Embodiment of this invention, and its manufacturing method.
[0024]
FIG. 1 is a schematic cross-sectional configuration diagram of a semiconductor pressure sensor manufactured by the semiconductor sensor manufacturing method according to the first embodiment of the present invention.
In FIG. 1, an impurity diffusion region 2 is formed on the surface of a Si substrate 1, and this impurity diffusion region 2 serves as a lower electrode.
[0025]
Further, a high concentration impurity diffusion region 7 is formed in the diaphragm portion 10 on the cavity portion 6, and this high concentration impurity diffusion region 7 serves as an upper electrode. The impurity diffusion region 2 and the high-concentration impurity diffusion region 7 are respectively implanted with N-type and P-type impurities to form a PN junction. When used in a reverse bias state, the upper electrode 7 and the lower electrode 2 are used. It is the structure which ensures insulation with.
[0026]
Further, in order to electrically connect the electrode portions 7 and 2 and the outside, an insulating layer 8 is formed, a contact hole is formed in the insulating layer 8, and the metal wiring 9 and each of the electrodes 7 and 2 are connected. Is connected.
[0027]
Next, the operation of the semiconductor pressure sensor according to the first embodiment of the present invention will be described.
In the example shown in FIG. 1, the cavity 6 serves as a reference pressure chamber, and the diaphragm 10 is displaced according to the external pressure applied. For example, if the external pressure increases, the diaphragm portion 10 bends toward the Si substrate 1 side.
[0028]
On the other hand, the electrostatic capacitance between the lower electrode 2 and the upper electrode 7 is inversely proportional to the height of the cavity 6, that is, the size in the vertical direction of FIG. Therefore, when the diaphragm 10 is displaced according to the external pressure, the height of the cavity 6 changes, and as a result, the capacitance changes. In the structure of the semiconductor pressure sensor in the first embodiment, a change in external pressure is detected as a change in capacitance.
[0029]
FIG. 2 is a process diagram of the manufacturing method of the semiconductor pressure sensor according to the first embodiment of the present invention.
In FIG. 2, first, in FIG. 2A, impurities are selectively implanted into the surface of the Si substrate 1 by ion implantation or the like, and an impurity diffusion region 2 is formed by heat treatment. This impurity diffusion region 2 becomes a lower electrode.
[0030]
Thereafter, a structure 3 in which a plurality of trenches (grooves) or a plurality of holes (holes) are formed in the impurity diffusion region 2 is dry-etched to form a trench width of 0.3 μm and a trench interval (between the trenches). The region width is 0.3 μm and the depth is 2 μm.
[0031]
FIG. 3 is a schematic plan view of the structure 3.
3A shows a case where a plurality of trenches 4 are formed in the impurity diffusion region 2, and FIG. 3B shows a case where a plurality of holes 5 are formed in the impurity diffusion region 2.
[0032]
The area for forming the structure 3 in the impurity diffusion region 2 is that the upper part of the structure 3 becomes the upper electrode 7. Therefore, the area for increasing the capacitance change is a 250 μm square area (250 μm × 250 μm). And
[0033]
Next, in FIG. 2B, the Si substrate 1 on which the structure 3 is formed is annealed (eg, heat treatment at 1100 ° C.) in a high temperature state, for example, in a hydrogen atmosphere or under a high vacuum. .
[0034]
When such annealing is performed, Si flows to move so as to minimize the surface area, so that a cavity 6 depending on the pattern of the structure 3 formed inside the Si substrate 1 is formed. The cavity 6 is used as a pressure reference chamber, and a part of the wall forming the pressure reference chamber is used as a diaphragm 10.
[0035]
By forming the structure 3 with the above dimensions, the lateral dimension of the cavity 6 is approximately 200 μm, the height dimension is 0.8 m, and the thickness of the diaphragm 10 is approximately 1 μm.
[0036]
Note that if the Si substrate 1 having the structure 3 in which a plurality of trenches or holes are formed is annealed in a high temperature state without oxidizing the surface, a cavity is formed in the impurity diffusion region 2 for different purposes. However, it is known in the field related to the manufacturing method of transistors.
[0037]
Next, in FIG. 2C, impurities are selectively introduced onto the diaphragm portion 10 by ion implantation or the like and diffused by heat treatment to form a high-concentration impurity diffusion region 7. This impurity diffusion region 7 becomes the upper electrode.
[0038]
Next, in FIG. 2D, an insulating layer 8 such as an oxide film or a nitride film is formed on the surface of the Si substrate 1 by a CVD method or the like, contact holes are formed by photoetching, and a metal film such as Al is formed. And metal wiring 9 is formed.
[0039]
As described above, the semiconductor pressure sensor according to the first embodiment of the present invention is manufactured.
[0040]
As described above, in the first embodiment of the present invention, by forming a plurality of trenches or holes in the impurity diffusion region 2 (1 step) and performing annealing (2 steps), the pressure reference chamber and the diaphragm portion are formed. Can be formed simultaneously.
[0041]
On the other hand, in the conventional technique, an insulating film is formed in the impurity diffusion region (1 step), an opening is formed in this insulating film (2 steps), and the cavity (pressure) is formed by etching from this opening. A reference chamber) was formed (3 steps), and the formed opening had to be sealed (4 steps).
[0042]
Therefore, according to the first embodiment of the present invention, a semiconductor pressure sensor capable of simplifying the manufacturing process, reducing cost, having high mechanical strength, and capable of measuring with high accuracy and a method for manufacturing the same are realized. can do.
[0043]
In addition, since a pressure sensor such as a diaphragm is formed on the surface of the semiconductor substrate, a reference pressure chamber is formed at the same time, so a large number of semiconductor pressure sensors can be manufactured simultaneously with the badge processing of the Si wafer, and the cost can be reduced. It becomes.
[0044]
In addition, since it matches a normal Si wafer process, a circuit for processing the sensor output can be easily integrated on the same chip.
[0045]
In addition, the diaphragm part is formed of single crystal silicon of the same material as the substrate, and the cavity part for forming the diaphragm is formed by reflow of Si atoms, so the corner part of the cavity part is rounded, Since the structure is such that stress is not easily concentrated on the diaphragm support portion, a semiconductor pressure sensor having high mechanical strength can be manufactured.
[0046]
Next, a second embodiment of the present invention will be described.
FIG. 4 is a schematic cross-sectional view of a semiconductor pressure sensor according to the second embodiment of the present invention. This second embodiment detects a change in pressure as a resistance change of a piezoresistor formed on a diaphragm. is there.
[0047]
In FIG. 4, similarly to the manufacturing process shown in FIG. 2, a plurality of trenches and the like are formed on the Si substrate 1 and annealed to form the cavity 6.
[0048]
A piezoresistor 11 using a diffused resistor is formed in the diaphragm 10 on the cavity 6. A surface insulating layer 12 for protecting the surface is formed on the surface of the piezoresistor 11. A contact hole is formed in a part of the surface insulating layer 12, and the piezoresistor 11 is connected to the metal wiring 13.
[0049]
Similarly to the first embodiment shown in FIG. 1, the second embodiment shown in FIG. 4 has the cavity 6 as a reference pressure chamber, and the diaphragm 10 is displaced according to the external pressure applied. For example, when the external pressure increases, the diaphragm 10 bends toward the Si substrate 1 side.
[0050]
Thus, if the diaphragm 10 bends, stress will generate | occur | produce in the diaphragm 10, As a result, the resistance value of the piezoresistor 11 formed in the surface of the diaphragm 10 will change, and pressure can be detected by it.
[0051]
FIG. 5 is a diagram showing the steps of the method for manufacturing the semiconductor pressure sensor according to the second embodiment of the present invention shown in FIG.
[0052]
5, first, in FIG. 5A, a structure 3 such as a plurality of trenches or holes is formed on the surface of the Si substrate 1 by a dry etching method.
[0053]
Next, in FIG. 5B, the Si substrate 1 on which the structure 3 is formed is annealed in a state where the surface is not oxidized at a high temperature, for example, in a hydrogen atmosphere or under a high vacuum.
[0054]
When such annealing is performed, as described above, since Si flows to move to minimize the surface area, the cavity 6 depending on the pattern of the structure 3 formed inside the Si substrate 1 is formed. The
[0055]
Next, in FIG. 5C, an impurity diffusion layer is formed on the Si substrate 1 by ion implantation or the like, and a piezoresistor 11 is formed.
[0056]
Next, in FIG. 5D, a surface insulating layer 12 is formed on the surface of the Si substrate 1 by using a CVD method or the like, and then contact holes are formed in a part of the formed surface insulating layer 12 by photoetching. After that, the metal wiring 13 is formed.
[0057]
As described above, the semiconductor pressure sensor according to the second embodiment of the present invention is manufactured.
[0058]
As described above, also in the second embodiment of the present invention, the same effect as that of the first embodiment can be obtained.
[0059]
Next, an insulation separation method between the sensor unit and the peripheral circuit element will be described.
FIG. 6 is an explanatory diagram of an insulation separation method between the semiconductor pressure sensor and other elements. In this isolation method, the STI technique used in the semiconductor integrated circuit manufacturing process is used. That is, this is a technique in which a trench is formed on the surface of the Si substrate 1 and the insulating film 14 is embedded in the trench portion.
[0060]
This STI technique is suitable for the insulation of the pressure sensor part because the insulation in the depth direction can be secured. Further, compared with the conventional LOCOS separation technique, there is an advantage that the horizontal plane line can be reduced, which is suitable for high integration.
[0061]
FIG. 7 is a top view of an example in which the semiconductor pressure sensor shown in FIG. 1 or FIG. 3 is arranged on the Si substrate 1, which is an explanatory diagram of the insulation separation method between the semiconductor pressure sensor and other elements. The STI insulating portion 15 is used for insulating and separating each sensor portion 16. In the example of FIG. 7, each sensor unit 16 can detect pressure, so that it is possible to detect pressure distribution on the surface of the substrate 1.
[0062]
Next, a third embodiment of the present invention will be described.
FIG. 8 is a schematic sectional view of a relative pressure detection type pressure sensor according to a third embodiment of the present invention. In the third embodiment, in the example shown in FIG. 1, Si is etched from the back side of the Si substrate 1 with an alkali etching solution to form an opening 24, and is opposed to the diaphragm 10 on the surface of the Si substrate 1. A diaphragm 17 is formed on the surface.
[0063]
Other configurations and manufacturing methods are the same as the example shown in FIGS. In addition, the same code | symbol is attached | subjected to the member equivalent to the example shown in FIG.
[0064]
Next, the operation of the semiconductor pressure sensor according to the third embodiment of the present invention will be described.
In FIG. 8, the cavity 6 serves as a reference pressure chamber, and the diaphragm 10 is displaced by the pressure applied from the surface side of the Si substrate 1. Moreover, the diaphragm part 17 is displaced by the pressure applied from the back surface side of the Si substrate 1.
[0065]
Therefore, the height of the cavity 6, that is, the distance between the diaphragm 10 and the diaphragm 17 is determined by the relative difference between the pressure on the front surface side and the pressure on the back surface side of the Si substrate 1. Become.
[0066]
By detecting this relative pressure difference as a change in capacitance that is inversely proportional to the height of the cavity 6, the apparatus shown in FIG. 8 can be used as a pressure sensor for detecting relative pressure.
[0067]
As described above, in the third embodiment of the present invention, the same effect as that of the first embodiment can be obtained, and the relative pressure is detected as the change in capacitance, so that the output fluctuation with respect to the temperature is relatively small. A pressure detection sensor can be realized.
[0068]
Next, a fourth embodiment of the present invention will be described.
FIG. 9 is a schematic cross-sectional view of a semiconductor pressure sensor according to a fourth embodiment of the present invention. This fourth embodiment is an example in which another pressure sensor is formed on a diaphragm.
[0069]
In FIG. 9, the cavity 6 and the diaphragm 10 are formed in the Si substrate 1 in the same manner as the manufacturing method shown in FIGS. 5 (a) and 5 (b). Next, after an insulating film 18 such as an oxide film is formed on the formed diaphragm portion 10 (first diaphragm), a fixed electrode 19 is formed. Then, an insulating layer 20 is further formed for insulating the fixed electrode 19. Thereafter, the movable electrode 22 (second diaphragm) having a scaffold portion is formed on the diaphragm 10.
[0070]
In this pressure sensor, a change in capacitance between the movable electrode 22 and the fixed electrode 19 is detected as a change in external pressure applied to the movable electrode 22.
[0071]
In the case of the pressure sensor having the mounting structure shown in FIG. 9, the movable electrode 22 and the fixed electrode 19 serving as a sensing portion are formed on the diaphragm 10, so that, for example, heat is applied from the outside, and the Si substrate 1 is caused by the thermal stress. Even when a strain is generated, the cavity 6 can reduce the strain, and the sensing portion is a pressure sensor that is not easily affected by the Si substrate 1 and is resistant to changes in the external environment.
[0072]
Therefore, according to the fourth embodiment of the present invention, a pressure sensor that is resistant to changes in the external environment is manufactured by simply adding a simple manufacturing process (the processes shown in FIGS. 5A and 5B). can do.
[0073]
Further, by forming the semiconductor pressure sensor on the diaphragm using the diaphragm itself of the present invention as a substrate, it is possible to realize a semiconductor pressure sensor in which the influence of distortion due to thermal stress from the substrate is reduced.
[0074]
Next, a fifth embodiment of the present invention will be described.
FIG. 10 is a schematic cross-sectional view and a plan view of a semiconductor sensor according to a fifth embodiment of the present invention. The fifth embodiment is an example of a semiconductor sensor that detects acceleration.
[0075]
Then, in the fifth embodiment, after forming the cavity 6 in the same manner as the manufacturing process shown in FIGS. 2A and 2B, the upper electrode portion on the diaphragm 10 is processed by photoetching, A movable electrode 25 having a cantilever structure is formed.
[0076]
Next, the operation of the semiconductor acceleration sensor according to the fifth embodiment of the present invention will be described.
In FIG. 10, when an acceleration is applied to the semiconductor acceleration sensor, the movable electrode portion 25 is displaced to the Si substrate 1 side or the opposite side because it has a cantilever structure. Here, the capacitance between the lower electrode 2 and the movable electrode 25 is inversely proportional to the height of the cavity 6, that is, the distance between the lower electrode 2 and the movable electrode 25.
[0077]
Therefore, when the movable electrode portion 25 is displaced according to the acceleration, the height of the cavity portion 6 changes, and as a result, the capacitance changes. In the structure of the fifth embodiment of the present invention, a change in acceleration is detected as a change in capacitance.
[0078]
Also in the fifth embodiment, the cavity 6 can be formed by a simple manufacturing process, and an acceleration detection sensor can be manufactured only by processing the surface of the Si substrate 1 thereafter. That is, according to the fifth embodiment of the present invention, a semiconductor acceleration sensor capable of simplifying the manufacturing process, reducing the cost, having high mechanical strength, and capable of measuring with high accuracy and a method for manufacturing the same are realized. can do.
[0079]
Next, a sixth embodiment of the present invention will be described.
FIG. 11 is a schematic cross-sectional view and a plan view of a semiconductor sensor according to a sixth embodiment of the present invention, and this sixth embodiment is an example of an airflow sensor that detects an air flow rate.
[0080]
In FIG. 11, the cavity 6 is formed by forming a plurality of trenches or holes in the Si substrate 1 and annealing under vacuum in the same manner as the manufacturing process shown in FIGS. 5A and 5B. To do. Then, after an insulating film 12 such as an oxide film is formed on the Si substrate 1 by thermal oxidation or the like, a poly-Si film is formed, and photo-etching is performed to form the heating resistor 26.
[0081]
Next, the operation of the semiconductor airflow sensor according to the sixth embodiment of the present invention will be described.
In FIG. 11, the heating resistor 26 is heated by passing an electric current. The temperature of the heating resistor 26 is lowered by the air flow coming into contact with the heating resistor 26. However, the current flowing through the heating resistor 26 is controlled by an external circuit so that the temperature of the heating resistor 26 becomes constant. The air flow rate is converted by the change of the flowing current, and it operates as an air flow sensor.
[0082]
As described above, also in the sixth embodiment, the cavity 6 can be formed by a simple manufacturing process, and a sensor for airflow detection having a high heat insulation effect only by subsequent processing of the surface of the Si substrate 1. Can be manufactured at low cost.
[0083]
That is, according to the sixth embodiment of the present invention, since the cavity 6 is evacuated, the heating resistor 26 can suppress heat from the outside other than air to be measured by the cavity 6. The mounting structure has a high thermal insulation effect.
[0084]
【The invention's effect】
According to the present invention, since the reference pressure chamber can be formed at the same time as forming the pressure detecting portion such as a diaphragm on the semiconductor substrate surface, the manufacturing process can be simplified, the cost can be reduced, and the mechanical strength can be reduced. And a manufacturing method of the semiconductor sensor capable of measuring with high accuracy and high accuracy can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional configuration diagram of a semiconductor pressure sensor manufactured by a semiconductor sensor manufacturing method according to a first embodiment of the present invention.
FIG. 2 is a process diagram of a method for manufacturing a semiconductor pressure sensor according to the first embodiment of the present invention.
FIG. 3 is a schematic plan view of a structure 3 in the first embodiment.
FIG. 4 is a schematic sectional view of a semiconductor pressure sensor according to a second embodiment of the present invention.
FIG. 5 is a diagram showing a process of a method for manufacturing a semiconductor pressure sensor according to the second embodiment of the present invention shown in FIG. 4;
FIG. 6 is an explanatory diagram of an insulation separation method between a semiconductor pressure sensor and other elements.
FIG. 7 is an explanatory diagram of a method for insulating and separating a semiconductor pressure sensor from other elements.
FIG. 8 is a schematic cross-sectional view of a relative pressure detection type pressure sensor according to a third embodiment of the present invention.
FIG. 9 is a schematic sectional view of a semiconductor pressure sensor according to a fourth embodiment of the present invention.
FIG. 10 is a schematic cross-sectional and plan view of a semiconductor sensor according to a fifth embodiment of the present invention.
FIG. 11 is a schematic cross-sectional and plan view of a semiconductor sensor according to a sixth embodiment of the present invention.
FIG. 12 is a schematic cross-sectional view of an example of a semiconductor pressure sensor in the prior art.
FIG. 13 is a schematic cross-sectional view of another example of a semiconductor pressure sensor in the prior art.
[Explanation of symbols]
1 Si substrate 2 Impurity diffusion region (lower electrode)
3 Structure 4 Trench 5 Hole 6 Cavity 7 High-concentration impurity diffusion region (upper electrode)
8 Insulating film 9 Metal wiring 10 Diaphragm 11 Piezoresistor 12 Surface insulating layer 13 Metal wiring 14 Insulating film 15 STI insulating part 16 Sensor part 17 Diaphragm part 18 Insulating film 19 Fixed electrode 20 Insulating film 21 Scaffold 22 Movable electrode 23 Sealing part 24 Opening 25 Movable electrode (cantilever)
26 Heating resistor

Claims (11)

In semiconductor sensors that convert mechanical displacement into electrical signals,
A plurality of grooves or holes are formed in a predetermined region of the semiconductor substrate, the semiconductor substrate in which the plurality of grooves or holes are formed is heat-treated, and a cavity is formed in the region of the semiconductor substrate in which the plurality of grooves or holes are formed. A semiconductor sensor characterized by forming a region. In semiconductor pressure sensor,
A plurality of grooves or holes are formed in a predetermined region of the semiconductor substrate, the semiconductor substrate in which the plurality of grooves or holes are formed is heat-treated, and a cavity is formed in the region of the semiconductor substrate in which the plurality of grooves or holes are formed. A semiconductor pressure sensor characterized in that a region is formed, the hollow region is used as a pressure chamber, a part of a wall portion of the pressure chamber is used as a diaphragm portion, and a pressure is measured by displacement of the diaphragm portion. In semiconductor acceleration sensors,
A plurality of grooves or holes are formed in a predetermined region of the semiconductor substrate, the semiconductor substrate in which the plurality of grooves or holes are formed is heat-treated, and a cavity is formed in the region of the semiconductor substrate in which the plurality of grooves or holes are formed. A region is formed, a part of the wall portion of the hollow region is used as a diaphragm portion, a movable electrode is formed on the diaphragm portion by etching the diaphragm portion, and acceleration is detected by displacement of the movable electrode. A semiconductor acceleration sensor. In semiconductor airflow sensor,
A plurality of grooves or holes are formed in a predetermined region of the semiconductor substrate, the semiconductor substrate in which the plurality of grooves or holes are formed is heat-treated, and a cavity is formed in the region of the semiconductor substrate in which the plurality of grooves or holes are formed. A semiconductor airflow sensor characterized in that a region is formed, a part of a wall portion of the cavity region is a diaphragm portion, and a heating resistor is formed on the diaphragm portion. 4. The semiconductor sensor according to claim 1, wherein corners of the hollow region are rounded with a radius of 0.3 [mu] m or more. 4. The semiconductor sensor according to claim 1, wherein peripheral portions forming the cavity region are made of the same single crystal material. 2. The semiconductor sensor according to claim 1, wherein a part of the wall portion forming the hollow region is a first diaphragm, and a scaffold part to be fixed is provided on the first diaphragm, and is displaced according to a change in pressure. A semiconductor pressure sensor characterized in that a second diaphragm is formed. In a manufacturing method of a semiconductor sensor for converting a mechanical displacement amount into an electrical signal,
Forming a plurality of grooves or holes in a predetermined region of the semiconductor substrate;
Heat treating the semiconductor substrate in which the plurality of grooves or holes are formed, and forming a cavity region in the region in which the plurality of grooves or holes are formed in the semiconductor substrate;
The manufacturing method of the semiconductor sensor characterized by the above-mentioned. In the manufacturing method of the semiconductor pressure sensor,
Forming a plurality of grooves or holes in a predetermined region of the semiconductor substrate;
The semiconductor substrate in which the plurality of grooves or holes are formed is heat-treated to form a cavity region in the region in which the plurality of grooves or holes are formed in the semiconductor substrate, and the cavity region is used as a pressure chamber. A step of making a part of the wall portion of the pressure chamber a diaphragm portion;
The manufacturing method of the semiconductor pressure sensor characterized by the above-mentioned. In a method for manufacturing a semiconductor acceleration sensor,
Forming a plurality of grooves or holes in a predetermined region of the semiconductor substrate;
The semiconductor substrate in which the plurality of grooves or holes are formed is heat-treated to form a cavity region in the region in which the plurality of grooves or holes are formed in the semiconductor substrate, and a part of the wall portion of the cavity region is a diaphragm. A process to be a part,
Etching the diaphragm part to form a movable electrode on the diaphragm part;
The manufacturing method of the semiconductor acceleration sensor characterized by the above-mentioned. In the manufacturing method of the semiconductor airflow sensor,
Forming a plurality of grooves or holes in a predetermined region of the semiconductor substrate;
The semiconductor substrate in which the plurality of grooves or holes are formed is heat-treated to form a cavity region in the region in which the plurality of grooves or holes are formed in the semiconductor substrate, and a part of the wall portion of the cavity region is a diaphragm. A process to be a part,
Forming a heating resistor on the diaphragm portion;
The manufacturing method of the semiconductor airflow sensor characterized by the above-mentioned.

Images