JP3318581B2 - Semiconductor flow measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor flow measuring device for measuring a flow rate of a fluid, which has a function of detecting dust deposited on the semiconductor flow measuring device and removing the detected dust. It is about.

[0002]

2. Description of the Related Art Generally, in an electronically controlled fuel injection system for an automobile engine, it is important to accurately measure the flow rate of intake air to the engine for controlling the air-fuel ratio.
As a device for measuring the flow rate of a fluid such as intake air, a vane type device has conventionally been the mainstream, but recently, a thermal type flow rate measuring device utilizing a fluid cooling effect of a heating element has become widespread. . The thermal type flow measuring device is characterized in that it can be miniaturized, can measure the inflow amount from the flow velocity, and has good responsiveness. Among them, a semiconductor flow measuring device in which a measuring element is formed on a semiconductor substrate by utilizing a semiconductor manufacturing process such as photolithography, diffusion, and etching has been actively studied.

FIG. 28 shows the structure of a conventional semiconductor flow measuring device. This is a sectional view of a semiconductor flow measuring device described in Japanese Patent Application Laid-Open No. 58-72059. In FIG. 28, reference numeral 30 denotes a semiconductor substrate having a single crystal structure, and 31 denotes a concave portion formed by performing anisotropic etching on the surface of the semiconductor substrate 30. 12 and 13 are insulator layers. Reference numeral 51 denotes a resistance element for detecting a flow rate. The resistance element 51 is mounted on the insulator layer 13 so as to be located above the concave portion 31. In addition, heat is generated by passing a current through the resistance element 51.
Further, since the insulator layer 13 exists between the resistance element 51 and the semiconductor substrate 30, the resistance element 51 and the semiconductor substrate 30 are electrically insulated. Further, the resistance value of the resistance element 51 changes depending on the relationship with the ambient temperature, and this relationship has been examined in advance. Reference numeral 12 denotes an insulator layer provided to protect the resistance element 51. The insulation layers 12 and 13 cover the resistance element 51. An opening (not shown) is formed above the concave portion 31 and near the resistance element 51 so that heat generated by the resistance element 51 can easily move upward. The opening (not shown) is formed so that the surface of the semiconductor flow measuring device and the recess 31 penetrate. Since the gas has a smaller thermal conductivity than the solid, the opening (not shown) makes it possible to suppress the heat generated from the resistance element 51 from diffusing into the insulator layers 12 and 13. Further, the depth of the concave portion 31 is
And the bottom of the concave portion 31 have such a depth as to be thermally insulated. Thermal conductivity is higher for solids than for gases. Therefore, by providing the opening (not shown) and the recess 31, it is possible to suppress the heat generated by the resistance element 51 from diffusing inside the insulator layers 12 and 13 and moving to the semiconductor substrate 30. Therefore, the heat generated from the resistance element 51 moves upward and is released to the atmosphere, so that the heat generated from the resistance element 51 can be used efficiently.

[0004] The semiconductor flow rate measuring device comprises a semiconductor substrate 30.
Is removed by using a technique such as anisotropic etching to form a concave portion 31, and by holding the insulating layers 12 and 13 on which the resistive element 51 is formed on the concave portion 31, Most of the resistance element 51 has a structure in which the resistance element 51 is not in contact with the semiconductor substrate 30.

Next, the operation of the semiconductor flow measuring device will be described. The principle of measuring the flow rate uses the following physical phenomena. That is, the amount by which the fluid removes the heat generated by the resistance element 51 depends on the flow velocity of the fluid. When a current flows through the resistance element 51, the resistance element 51 generates heat. The heat generated from the resistance element 51 is taken away by the fluid flowing into the semiconductor flow rate measuring device.
It depends on the flow rate of the fluid. On the other hand, since the temperature of the resistance element 51 changes due to the deprivation of heat, the resistance value changes. Therefore, the flow rate of the flowing fluid can be detected by checking the resistance value.

[0006]

The above-described semiconductor flow rate measuring apparatus has a problem of accumulation of dust contained in a fluid. In the conventional semiconductor flow rate measuring device, the opening (not shown) and the recess 31 are provided so that the heat generated by the resistance element 51 can easily move upward. That is, the provision of the opening (not shown) is for suppressing the heat generated by the resistance element 51 from diffusing into the insulator layers 12 and 13, and the provision of the recess 31 is provided for the resistance element 51. 5
This is to reduce the loss due to heat conduction from 1 to the semiconductor substrate 30. However, due to the presence of the opening (not shown), dust smaller than the size of the opening (not shown) may enter the recess 31 and accumulate. The dust accumulates in the concave portion 31 so that the resistance element 51
A part of the heat that is supposed to be released to the atmosphere is transmitted to the semiconductor substrate through the dust, which changes the amount of heat released to the atmosphere, causing an error when measuring the flow rate It becomes a factor.

If the dust is larger than the opening (not shown), the opening (not shown) may be blocked. If the dust blocks the opening, much heat generated from the resistance element 51 is dissipated by the insulating layers 12 and 13.
Not only does it diffuse into the inside, but it also disturbs the flow of the fluid flowing near the upper part of the resistance element 51, and causes an error when measuring the flow rate.

[0008] As described above, the dust contained in the fluid accumulates on the semiconductor flow rate measuring device, which causes an error in the flow rate measurement. Since the semiconductor flow measurement device is exposed to the fluid, if the fluid contains dust, the dust may accumulate on the semiconductor flow measurement device. Therefore, it is necessary to detect the accumulation of dust and desirably remove the accumulated dust to prevent deterioration of the characteristics of the sensor and malfunction.

However, the conventional semiconductor flow rate measuring apparatus does not have a function of detecting such dust accumulation or a function of removing accumulated dust. SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems, and it is an object of the present invention to detect dust that blocks an opening or dust that accumulates in a concave portion and removes the dust.

[0010]

According to a first aspect of the present invention, there is provided a semiconductor flow measuring device for measuring a flow rate of a fluid by arranging the semiconductor substrate in a fluid, the semiconductor substrate having a concave portion on a surface thereof; A heating element disposed above the concave portion via a space that provides thermal insulation with the semiconductor substrate, wherein a characteristic of the heating element changes in accordance with a flow rate of the surrounding fluid to reduce a flow rate of the fluid. In a semiconductor flow rate measuring device capable of measuring, in order to detect dust accumulated in a space enough to provide the thermal insulation ,
A first electrode disposed above, and a first electrode disposed on a bottom surface of the concave portion;
A dust detection element comprising a second electrode .

[0011] Semiconductor flow measurement equipment according to claim 2,
An apparatus for measuring a flow rate of a fluid by arranging the semiconductor substrate in a fluid, the semiconductor substrate having a concave portion on a surface thereof, and a heat generator disposed above the concave portion via a space providing thermal insulation with the semiconductor substrate. A semiconductor flow rate measuring device capable of measuring the flow rate of the fluid by changing the characteristics of the heating element in accordance with the flow rate of the surrounding fluid. In order to detect dust accumulated in the inside, a dust detection element including a temperature-sensitive resistor disposed on a bottom surface of the concave portion is provided.

[0012] Semiconductor flow measurement equipment according to claim 3,
An apparatus for measuring a flow rate of a fluid by arranging the semiconductor substrate in a fluid, the semiconductor substrate having a concave portion on a surface thereof, and a heat generator disposed above the concave portion via a space providing thermal insulation with the semiconductor substrate. A semiconductor flow rate measuring device capable of measuring the flow rate of the fluid by changing the characteristics of the heating element in accordance with the flow rate of the surrounding fluid. And a dust detecting element including a first electrode disposed above the concave portion and a second electrode disposed on the outer periphery of the concave portion for detecting dust accumulated in the inside. Things.

[0013] Semiconductor flow measurement equipment according to claim 4,
An apparatus for measuring a flow rate of a fluid by arranging the semiconductor substrate in a fluid, the semiconductor substrate having a concave portion on a surface thereof, and a heat generator disposed above the concave portion via a space providing thermal insulation with the semiconductor substrate. A semiconductor flow rate measuring device capable of measuring the flow rate of the fluid by changing the characteristics of the heating element in accordance with the flow rate of the surrounding fluid. In order to detect dust accumulated in the inside, a dust detection element including a temperature-sensitive resistor disposed on an outer periphery of the concave portion is provided.

[0014] Semiconductor flow measurement equipment according to claim 5,
A device for measuring the flow rate of a fluid by placing the fluid in the fluid
A semiconductor substrate having a concave portion on the surface;
Over the recess through a space that provides thermal insulation with the conductive substrate
And a heating element arranged on the side, wherein the characteristics of the heating element are
By changing according to the flow velocity of the surrounding fluid,
Semiconductor flow rate measuring device capable of measuring fluid flow rate
Dust deposited in the space providing the thermal insulation
A first arranged above the recess to remove
An electrode and a second electrode disposed on the bottom surface of the recess.
A dust removing element is provided .

A semiconductor flow measuring device according to claim 6 is
An apparatus for measuring a flow rate of a fluid by being disposed in a fluid , comprising: a semiconductor substrate; and an insulator disposed on the semiconductor substrate.
The layer is convex and a cavity is provided inside, and the space of the cavity
A heating element disposed above the semiconductor substrate via
Wherein the characteristics of the heating element correspond to the flow velocity of the surrounding fluid.
Measuring the flow rate of the fluid by changing
In a semiconductor flow measurement device capable of
In order to detect dust that accumulates in the space that gives
A first electrode and a second electrode in a space for providing thermal insulation;
And a dust detection element comprising:

A semiconductor flow measuring device according to claim 7 is
An apparatus for measuring a flow rate of a fluid by being disposed in a fluid, comprising: a semiconductor substrate; and an insulator disposed on the semiconductor substrate.
The layer is convex and a cavity is provided inside, and the thermal
Above the semiconductor substrate via a space that provides insulation
And a heating element disposed in the vicinity of the heating element.
The flow is varied by changing the flow rate of the surrounding fluid.
A semiconductor flow measurement device that can measure body flow
Deposited in a space that provides thermal insulation.
In order to detect dust, in the space giving the thermal insulation
A dust detection element comprising a temperature-sensitive resistor is provided .

[0017] Semiconductor flow measurement equipment according to claim 8,
An apparatus for measuring a flow rate of a fluid by arranging the same in a fluid, comprising a semiconductor substrate and a cavity formed therein with an insulator layer formed on the semiconductor substrate in a convex shape, and thermally insulating the cavity. A heating element disposed above the semiconductor substrate via a given space, and measuring the flow rate of the fluid by changing the characteristics of the heating element in accordance with the flow velocity of the surrounding fluid. In a possible semiconductor flow measuring device, a first electrode and a second electrode disposed in the space for providing thermal insulation to remove dust accumulated in the space for providing thermal insulation. And a dust removing element comprising:

[0018]

The semiconductor flow measuring device according to any one of the first to fourth and sixth and seventh aspects makes it possible to detect dust accumulated in a space that can keep thermal insulation.

The semiconductor flow measuring device according to any one of claims 5 and 8 makes it possible to remove dust accumulated in a space enough to maintain thermal insulation.

[0020]

[Embodiment 1] FIG. 1A is a plan view showing a semiconductor flow measuring device according to a first embodiment of the present invention, and FIG. 1B is a sectional view of the semiconductor flow measuring device according to the first embodiment. The present embodiment is characterized in that two electrodes are used as a dust detection element for detecting accumulation of dust and a dust removal element for removing accumulated dust. In FIG. 1, reference numeral 30 denotes a semiconductor substrate of single crystal silicon or the like. Is formed.
Since the recess 31 is located at an appropriate distance from the end of the semiconductor substrate 30, the fluid flowing on the insulator layer 12 is close to a laminar flow. Reference numerals 12, 13 and 14 are insulator layers made of an insulating material such as SiO2 or SiN. 1
Reference numeral 6 denotes a heating element having conductivity such as a resistance, and both ends of the heating element 16 are located on a diagonal line of a square concave portion 31,
At least one end is located on the insulator layer 13. Reference numeral 20 denotes an electrode attached to the bottom surface of the concave portion 31 for detecting dust accumulated on the concave portion 31. Reference numeral 18 denotes an electrode for detecting dust deposited on the concave portion 31. The electrode 18 is positioned so as to bridge over the concave portion 31, and both ends thereof are fixed on the insulator layer 14. In the electrode 18, a portion located above the concave portion 31 faces the outside air. In addition, the electrode 18 and the electrode 20 form a capacitor.

Reference numeral 32 denotes an opening formed by removing the insulating layers 12 and 13 located above the recess 31 and near the heating element 16 by etching or the like. By forming the opening 32, it is possible to suppress the heat generated by the heating element 16 from diffusing in the insulator layers 12, 13, and 14. The insulating layer 12, the insulating layer 13, the heating element 16, and the electrode 18 located above the concave portion 31 by the opening 32 have a structure bridging the upper portion of the concave portion 31.
Is configured. Although the bridge portion 100 has a structure that bridges over the concave portion 31, one end of the bridge portion 100 may be opened to have a cantilever structure. Bridge 10
At 0, the heating element 16 is covered by the insulator layers 12 and 13, and the electrode 18 is located below the insulator layer 13.

As the heating element 16, an element whose characteristic (for example, resistance value) changes when the temperature changes is used. It is assumed that the characteristics of the heating element 16 with respect to the temperature are known in advance because they have been examined by experiments and the like. FIG. 2A shows an example in which the heating element 16 is incorporated in the semiconductor flow rate measuring apparatus of the first embodiment, and FIG. 2B shows an enlarged view of the heating element 16. In FIG.
Reference numeral 1 denotes a heating unit made of a silicide such as platinum or W-Si. The heating element 16 generates heat when a current flows through the heating unit 161. The heating section 161 is corrugated so as to increase its resistance value.
The amount of heat generated by 61 increases. 162 is a heating unit 1
This is a lead portion connecting the first and second components 61, and the tip of the lead portion 162 serves as a terminal for connecting to another element. The material of the lead portion 162 may be the same as the material of the heat generating portion 161, but the material of the lead portion is Al or Cu having a small resistance value.
When such a material is used, the heat generated by the current flowing through the lead portion 162 can be designed to be sufficiently smaller than the heat generated by the current flowing through the heat generating portion 161. Alternatively, when the material of the lead portion 162 is the same as the material of the heat generating portion 161, simply increasing the width of the lead portion 162 in comparison with the width of the heat generating portion 162 is not sufficient.
The heat generated by the current flowing through 62 can be designed to be sufficiently smaller than the heat generated by the current flowing through the heat generating portion 161. As shown in FIG. 2, the heating element 16 is located on the insulator layer 13, and the heating section 161 is located above the recess 31. Since heat moves from a high temperature to a low temperature, most of the heat generated by the heating element 16 moves to the surface of the insulator layer 12 and is released to the atmosphere.

Next, a method for measuring a flow rate using the semiconductor flow rate measuring device of FIG. 1 and a method for detecting dust deposited on the semiconductor flow rate measuring device will be described. First, a method for measuring the flow rate will be described. After checking characteristics (resistance, etc.) of the heating element 16 with respect to temperature in advance, in order to detect a flow rate, a current is applied to the heating element 16 so that the heating element 16 generates a constant amount of heat per unit time, and an output is generated. A flow rate measurement circuit (not shown) whose value depends on a change in resistance value due to a change in temperature of the heating element 16 is configured. When a current flows through the heating element 16, the heating element 16 generates heat, and the generated heat moves to the surface of the insulating layer 12 and is released to the atmosphere. The released heat is taken away by the fluid flowing on the surface of the semiconductor flow measuring device. The temperature of the heating element 16 changes as the heat released to the atmosphere is taken away. The amount by which the temperature changes depends on the flow rate of the fluid. When the temperature of the heating element 16 changes, the resistance value of the heating element 16 changes. When the resistance value of the heating element 16 changes, the output value of the flow measurement circuit (not shown) changes. Therefore, the output value of the flow measurement circuit (not shown) changes depending on the value of the flow velocity of the fluid flowing through the semiconductor flow measurement device. Therefore, if the relationship between the flow rate and the flow rate at the measurement position is checked in advance, the flow rate of the fluid can be measured by checking the characteristics of the output value with respect to the flow rate of the fluid.

Next, a method for detecting dust accumulated on the semiconductor flow measuring device will be described. First, a dust detection circuit (not shown) is configured to detect a change in capacitance of a capacitor formed between the electrode 18 and the electrode 20 for detecting dust.

FIG. 3 is a view showing a state in which dust is deposited on the semiconductor flow measuring device. In FIG. 3, reference numeral 200 denotes dust accumulated in the semiconductor flow rate measuring device. Since the dust 200 is accumulated in the concave portion 31, heat generated from the heating element 16 is transmitted to the semiconductor substrate 30 via the dust 200.
Therefore, heat that should be released to the atmosphere is transmitted to the semiconductor substrate 30, and the amount of heat released to the atmosphere via the insulating layer 12 changes, thereby causing an error in the measured flow rate. At this time, the dust 2 is placed between the electrode 18 and the electrode 20.
The accumulation of 00 changes the capacitance of the capacitor formed by the electrode 18 and the electrode 20. Therefore, when a dust detection circuit (not shown) detects a change in capacitance, it is determined that dust has accumulated. By configuring such a dust detection circuit (not shown), it is possible to confirm the presence of dust 200 that accumulates in the recess 31.

When a large amount of dust 200 accumulates in the concave portion 31, heat transfer to the substrate 30 increases, which causes an error in measuring the flow rate. Therefore, simply detecting the dust 200 is not sufficient, and it is necessary to remove the dust 200 after detecting the dust 200. When the dust 200 has conductivity, the dust 200 can be removed by the following method. Dust detection circuit (not shown)
Detects dust 200, after the measurement of the flow rate by the flow rate measurement circuit (not shown) is completed, the dust removal circuit (not shown) operates to cause a current to flow between the electrode 18 and the electrode 20, The dust 200 is heated to about several hundred degrees. By heating the dust 200 to about several hundred degrees, the dust 20 is heated.
0 is burned off, and the dust 200 deposited on the concave portion 31 is removed. As described above, by operating the dust removal circuit (not shown) after the measurement of the flow rate, the heat released when the dust is heated does not affect the measurement of the flow rate. Can be operated.

As described above, the presence of the dust 200 deposited on the concave portion 31 of the semiconductor flow measuring device can be confirmed by the dust detection circuit (not shown) and the dust removal circuit (not shown). Since the dust 200 can be removed, it is possible to prevent an error from occurring when measuring the flow rate.

In this example, the dust detection circuit includes the electrode 18 and
Although the circuit configuration is such that the capacitance between the electrodes 20 is detected, the circuit configuration may be such that the resistance value between the electrodes 18 and 20 is detected. In this case, when the dust 200 accumulates in the concave portion 31, a current flows between the electrode 18 and the electrode 20 via the dust 200, so that the resistance value between the electrode 18 and the electrode 20 changes. Thus, electrode 1
If the resistance value between the electrode 8 and the electrode 20 changes, it may be determined that dust is accumulated. By configuring the dust detection circuit (not shown) as described above, it is possible to confirm the accumulation of the dust 200.

FIG. 4 is a cross-sectional view of the semiconductor flow measuring device in each step for explaining the method of manufacturing the semiconductor flow measuring device according to the first embodiment. After a doping protective film 110a is formed and patterned on the n-type semiconductor substrate 30, a p-type impurity is doped to diffuse the p-type impurity layer 111 to a desired thickness (step (a)). Next, the p formed on the surface of the semiconductor substrate 30
A doping protective film 110b is formed to protect the n-type impurity layer 111, and an n-type impurity is doped and diffused.
m. The p-type impurity layer 111 of the semiconductor substrate formed in this step becomes the electrode 20 (step (b)). Next, a sacrificial layer 120 made of polysilicon or the like is formed on a portion where the concave portion 31 is to be formed, and an insulator layer 14 made of SiO2 or SiN is formed on other portions. An electrode 18 made of silicide such as Si or polycrystalline silicon is formed (step (c)). Next, the insulator layer 13,
The heating element 16 and the insulator layer 12 are formed (step (d)). Next, the insulator layer 1 is formed in order to form the recess 31.
2. After forming an opening 32 by etching a part of the insulator layer 13 to the surface of the sacrificial layer 120,
The sacrificial layer 120 is removed with an etchant of an alkali such as TMAH (tetramethylammonium hydroxide) or KOH, and the semiconductor substrate 30 is etched near the surface of the electrode 20 or until the surface of the electrode 20 appears. The sacrifice layer 120 is removed by etching, and the concave portion 31 and the bridge portion 100 are formed (step (e)).

In this example, the semiconductor substrate 30 is of the n-type and the impurity layer is of the p-type. However, if the semiconductor substrate 30 is of the p-type, the n-type impurity is doped to form the electrode 20 in the step (a). Then, in the step (b), by doping a p-type impurity, a semiconductor flow rate measuring device can be manufactured even with a p-type semiconductor substrate. With the above-described manufacturing method, it is possible to manufacture a semiconductor flow measurement device capable of detecting dust 200 deposited on the concave portion 31 and removing the dust 200.

Embodiment 2 FIG. FIG. 5 is a plan view of a semiconductor flow measurement device according to the second embodiment,
FIG. The present embodiment is characterized in that two electrodes are used for a dust detection element for detecting dust accumulated in the opening and a dust removal element for removing dust accumulated in the opening. If the size of the dust is larger than the size of the opening 32, the dust 200 may block the opening 32. When the dust 200 closes the opening 32, heat generated from the heating element 16 is transferred to the insulator layer 1.
In addition to the diffusion in the fluid 2 and 13, the flow of the fluid flowing on the surface of the semiconductor flow measuring device is disturbed, which causes an error in measuring the flow. The semiconductor flow rate measuring apparatus according to the second embodiment is characterized in that the provision of the electrode 18 and the electrode 20 on the insulator layer 12 makes it possible to detect dust that blocks the opening 32 and remove it. It is. In the semiconductor flow rate measuring device of FIG. 5, the method of detecting the flow rate is the same as that of the first embodiment, and therefore the description is omitted here. In the semiconductor flow measuring device of FIG. 5, a method of detecting dust accumulated in the opening 32 and removing the dust will be described. First, in order to detect dust, the electrodes 18 and 2
A dust detection circuit (not shown) capable of detecting a change in resistance value between 0 and 0, and when the dust detection circuit (not shown) determines that dust is deposited, the electrodes 18 and 20 And a dust removing circuit (not shown) for passing an electric current enough to burn out the dust accumulated between them.

FIG. 6 is an explanatory view showing a state in which dust blocks the opening 32 of the semiconductor flow measuring device. In FIG. 6, reference numeral 200 denotes dust accumulated in the opening 32. Since the dust 200 is accumulated in the recess 31, the flow of the fluid flowing on the surface of the semiconductor flow measuring device is disturbed. At this time, a current flows between the electrode 18 and the electrode 20 via the dust 200, so that the resistance value between the electrode 18 and the electrode 20 changes. Therefore, when a dust detection circuit (not shown) detects a change in the resistance value, it is determined that dust has accumulated.

When a large amount of dust 200 is deposited on the opening 32, the heat generated by the heating element 16 is
In order to greatly disturb the movement of the fluid flowing on the surface of the semiconductor flow measurement device,
This may cause errors in the measured flow rate. Therefore, dust 2
It is not sufficient to simply detect 00, and it is necessary to remove the dust 200 after detecting the dust 200.

The method of removing the dust 200 accumulated in the opening 32 is similar to that of the first embodiment, and a dust removing circuit (not shown) is configured to remove the dust 200 accumulated in the opening 32. It is possible.

With such a configuration, the presence of dust 200 deposited on the opening 32 of the semiconductor flow rate measuring device can be confirmed, and the dust 2 deposited on the opening 32 can be confirmed.
The removal of 00 makes it possible to operate the flow rate measurement normally.

FIG. 7 is an explanatory diagram for illustrating a method of manufacturing the semiconductor flow measuring device of the second embodiment. After forming the insulator layer 13 on the semiconductor substrate 30, the heating element 16 is formed on the insulator layer 13 (step (a)). Next, the insulator layer 1
3, and after forming the insulator layer 12 on the heating element 16, the electrodes 18 and 20 are formed on the insulator layer 12 (step (b)). The electrode 18 and the electrode 20 are Pt
In the case of a metal that does not react with an etchant such as, for example, a mask treatment is performed, the opening 32 is formed by etching to the surface of the semiconductor substrate 30, and then the semiconductor exposed to the outside air is formed by forming the opening 32. The concave portion 31 is formed by etching the substrate 30 (step (c)). The electrode 18 and the electrode 20 are made of Al or Cu
In the case of a metal that reacts with an etchant such as, for example, an insulating layer (not shown) is formed to protect the electrodes 18 and 20, and then the opening 32 is formed. The semiconductor substrate 30 exposed to the outside air by the fabrication of
Then, an insulator layer (not shown) formed to protect the electrodes 18 and 20 is removed.

The opening 32 is formed by the above-described manufacturing method.
It is possible to manufacture a semiconductor flow measurement device capable of detecting and removing dust 200 blocking dust.

Embodiment 3 FIG. FIG. 8 is an upper plan view and a sectional view showing a semiconductor flow measuring device according to Embodiment 3 of the present invention. In FIG. 8, 1
Reference numeral 50 denotes a temperature-sensitive resistor made of a conductive material, and it is assumed that the resistance characteristics of the temperature-sensitive resistor 150 with respect to temperature have been examined in advance.

This embodiment is characterized in that a temperature sensing resistor is used as a dust detecting element for detecting dust accumulated in the recess 31 and a dust removing element for removing dust accumulated in the recess 31. is there. By detecting the resistance value of the temperature-sensitive resistor 150, the accumulation of dust can be detected.
A method for detecting the accumulation of dust in the third embodiment will be described. In order to detect the accumulation of dust, a dust detection circuit (not shown) for detecting the resistance value of the temperature-sensitive resistor 150 is configured in advance. FIG. 9 shows a state diagram when dust accumulates in the recess 31. Referring to FIG.
00 is accumulated, the heat generated in the heat generating portion 16 is
00 to the temperature-sensitive resistor 150. Therefore, the temperature of the temperature-sensitive resistor 150 rises, and the temperature of the temperature-sensitive resistor 150 changes. Therefore, by detecting a change in the resistance value of the temperature-sensitive resistor 150 by a dust detection circuit (not shown), the accumulation of dust can be detected.

When the accumulation of dust 200 is detected,
After the flow rate is measured, the dust 200 can be removed by forming a dust removal circuit (not shown) for flowing a current enough to burn out the dust 200 to the temperature-sensitive resistor 150. Thus, it is possible to check whether dust is accumulated on the semiconductor flow rate measuring device, and when it is confirmed that dust is accumulated, it is possible to remove the dust.

Next, a method for manufacturing the semiconductor flow rate measuring device according to the third embodiment is shown in FIG. After forming a protective film for doping 110 a (not shown) on the n-type semiconductor substrate 30 and patterning the temperature-sensitive resistor 150, a p-type impurity is doped to form a desired p-type impurity layer 111. After being diffused to the thickness, the doping protection film 110 a is formed to protect the p-type impurity layer 111 formed on the surface of the semiconductor substrate 30.
(Not shown), the protective film 110 for doping is removed.
b is deposited, and an n-type impurity is doped and diffused, so that the p-type impurity layer 111 below the diffusion has a thickness of about several hundred nm. This p-type impurity layer 111 forms the temperature-sensitive resistor 15
0 (step (a)). Next, doping protective film 1
After removing 10b, an insulating layer 13, a heating element 16, and an insulating layer 12 made of SiO2, SiN, or the like are formed (step (b)). Next, after opening a window for substrate etching, the concave portion 31 is etched by etching the semiconductor substrate 30 with an alkali etchant such as TMAH (tetramethylammonium hydroxide) or KOH.
And the bridge portion 100 having the insulator layers 12 and 13 and the heating element 16 are formed (step (c)).

In the method of manufacturing a semiconductor flow measuring device described above, the semiconductor substrate 30 is of an n-type. The semiconductor substrate 30 is p
In the case of the p-type semiconductor substrate 30, in the step (a), after doping an n-type impurity and then doping a p-type impurity, the n-type impurity layer 111 is formed. This also makes it possible to manufacture a semiconductor flow measurement device.

According to the above-described method, it is possible to manufacture a semiconductor flow measuring device capable of detecting dust 200 deposited on the concave portion 31 and removing the dust 200.

Embodiment 4 FIG. FIG. 11 is a plan view and a sectional view of a semiconductor flow measuring device according to a fourth embodiment. In FIG. 11, reference numerals 12 and 13 denote insulating layers made of an insulating material, 150 denotes a temperature-sensitive resistor made of a conductive material, and the temperature-sensitive resistor 150 is mounted near the opening 32. The body 150 is mounted on the surface of the semiconductor flow measuring device, that is, on the insulator layer 12. Reference numeral 31 denotes a concave portion formed in a part of the semiconductor substrate 30.

In this embodiment, a temperature sensing resistor is used as a dust detecting element for detecting dust accumulated in the opening 32 and a dust removing element for removing accumulated dust. That is, this embodiment is characterized in that the temperature-sensitive resistor 150 is provided near the opening 32. This temperature sensitive resistor 15
By checking the resistance value of 0, it is possible to detect the accumulation of dust that blocks the opening 32. The method for measuring the flow rate is the same as that in the first embodiment, and will not be described here. The method of removing dust is the same as that of the third embodiment, and therefore will not be described here. A method for detecting dust that blocks the opening will be described. A dust detection circuit (not shown) for detecting the resistance value of the temperature-sensitive resistor 150 for detecting the dust blocking the opening 32 is configured. For example, when dust 200 accumulates on the opening 32 as shown in FIG. 12, heat is conducted from the heat generating portion 16 through the dust 200 and the temperature of the temperature-sensitive resistor 150 is increased. It becomes possible.

When the accumulation of dust 200 is detected,
After the flow rate is detected, the dust 200 can be removed by forming a dust removal circuit (not shown) that causes the temperature-sensitive resistor 150 to pass a current enough to burn the dust 200. Thus, it is possible to check whether dust is accumulated on the semiconductor flow rate measuring device, and when it is confirmed that dust is accumulated, it is possible to remove the dust.

Next, a method of manufacturing the semiconductor flow measuring device of the fourth embodiment will be described. FIG. 13 is an explanatory diagram for illustrating a method of manufacturing the semiconductor flow measurement device according to the fourth embodiment. After forming the insulator layer 13 on the semiconductor substrate 30, the heating element 16 is formed on the insulator layer 13 (step (a)). Next, after the insulator layer 12 is formed on the insulator layer 13 and the heating element 16, the temperature-sensitive resistor 150 is formed on the insulator layer 12 (step (b)). When the temperature-sensitive resistor 150 is made of a metal that does not react with an etchant such as Pt, after performing a mask process, the opening 32 is formed by etching to the surface of the semiconductor substrate 30 and then the opening 32 is formed. Thus, the semiconductor substrate 30 exposed to the outside air is subjected to (anisotropic) etching to form the concave portion 31 (step (c)). The temperature sensitive resistor 150 is Al or Cu
In the case of a metal that reacts with an etchant such as, for example, an insulating layer (not shown) is formed to protect the temperature-sensitive resistor 150, and then the opening 32 is formed.
Semiconductor substrate 10 exposed to the outside air by fabricating
Is etched (anisotropic) to form a concave portion 31, and then, an insulating layer (not shown) formed to protect the temperature-sensitive resistor 150 is removed.

According to the above-described manufacturing method, it is possible to manufacture a semiconductor flow measuring device for detecting dust that blocks the opening 32 and removing the dust.

Embodiment 5 FIG. FIG. 14 is a perspective view showing a semiconductor flow measuring device according to the fifth embodiment. FIG. 15 is a cross-sectional view of the semiconductor flow measuring device of the fifth embodiment. In the above embodiments, the semiconductor substrate 30
In contrast, the semiconductor flow rate measuring device of the fifth embodiment has a convex portion, a hollow portion provided therein, and a dust detecting element for detecting the accumulation of dust in the hollow portion. It is characterized by having a dust removing element for removing accumulated dust. Further, in this embodiment, as a dust detection element for detecting dust accumulated in the cavity and a dust removal element for removing accumulated dust, electrodes were provided on the upper surface and the lower surface in the cavity. It is a feature. 14 and 15, reference numeral 21 denotes a hollow portion provided so as to penetrate the inside of the insulator layer 13 having a convex shape. The hollow portion 21 enhances thermal insulation between the heating element 16 and the semiconductor substrate 30. As well as a fluid flow path. FIG. 16 shows an example of the heating element 16 used in the semiconductor flow measuring device of the fifth embodiment. The heating element 16 has a heating section 161 and a lead section 162 and is mounted such that the heating section 161 is located above the cavity 21. Further, by selecting a material of the lead portion 162 from a material having a sufficiently smaller heat generation amount than that of the heat generating portion 161, heat generated by the lead portion can be ignored.

First, a method for measuring the flow rate will be described. After checking the characteristics of the resistance of the heating element 16 with respect to the temperature in advance, in order to detect the flow rate, a current is applied to the heating element 16 so that the heating element 16 generates a constant amount of heat per unit time,
In addition, a flow rate measuring circuit (not shown) is configured such that the output value depends on a change in resistance value due to a change in temperature of the heating element 16. When a current flows through the heating element 16, the heating element 16 generates heat, and the generated heat moves to the surface of the insulating layer 12 or the surface of the cavity 21 and is released to the atmosphere. The released heat is taken away by the fluid flowing into the semiconductor flow measuring device. The temperature of the heating element 16 changes as the fluid that has released into the atmosphere is taken by the fluid. The amount by which the temperature changes depends on the flow rate of the fluid. When the temperature of the heating element 16 changes, the resistance value of the heating element 16 changes. Heating element 16
Changes the output value of the flow rate measurement circuit (not shown). Therefore, the output value of the flow measurement circuit (not shown) changes depending on the fluid flowing through the semiconductor flow measurement device. Therefore, if the relationship between the flow rate and the flow rate at the measurement position is checked in advance, the flow rate of the fluid can be measured by checking the characteristics of the output value with respect to the flow rate of the fluid. Further, the method of detecting and removing dust entering the hollow portion 21 is the same as that of the first embodiment, and a description thereof will be omitted.

Next, a method of manufacturing the semiconductor flow measuring device according to the fifth embodiment will be described. FIG. 17 is a cross-sectional view illustrating a method of manufacturing the semiconductor flow measurement device according to the fifth embodiment in the order of steps. An insulator layer 14 made of silicon nitride, silicon oxide, or the like is formed on the semiconductor substrate 30, and an electrode 20 made of a conductive material is patterned and formed. Then, a sacrificial layer 120 made of polysilicon or the like is deposited, An electrode 18 made of a conductive material is formed (step (a)). Next, the insulator layer 1
3. The heating element 16 made of a metal such as platinum or a silicide such as W-Si, and the insulator layer 12 are formed (step (b)). Next, the sacrificial layer 120 is removed with an etchant such as TMAH (tetramethylammonium hydroxide) or KOH to form a cavity 21 (step (c)).

By the above manufacturing method, the cavity 21
It is possible to manufacture a semiconductor flow measurement device capable of detecting dust accumulated on a surface and removing the dust.

Embodiment 6 FIG. FIG. 18 is a perspective view showing a semiconductor flow measuring device according to Embodiment 6 of the present invention, and FIG. 19 is a sectional view thereof. In FIGS. 18 and 19, reference numeral 17 denotes a heating element having conductivity such as a resistor for removing dust accumulated in the hollow portion 21, and generates heat by passing a current through the heating element 17. FIG. 20 shows an example of the heating element 17.
The heating element 17 has a heating section 171 and a lead section 172 and is mounted such that the heating section 171 is located on the electrode 20. Further, by selecting the material of the lead portion 172 from a material having a sufficiently smaller amount of heat generation than the heat generating portion 171, it is possible to ignore the heat generated by the lead portion. Although the heating element 17 has been described as being on the electrode 20, an insulating layer may be formed on the electrode 20 and the heating element 17 may be formed thereon (not shown). In this embodiment, the cavity 2 is used as a dust detection element for detecting the accumulation of dust in the cavity 21.
1, two electrodes are provided, and a heating element 17 is provided in the hollow portion 21 as a dust removing element for removing accumulated dust.
It is characterized by having.

The method for measuring the flow rate is the same as that in the fifth embodiment, and will not be described here. The method of detecting dust accumulated in the hollow portion 21 is the same as that in the fifth embodiment, and will not be described here. A method for removing dust accumulated in the gap will be described. First, in order to remove dust accumulated in the voids, a dust removal circuit (not shown) for supplying a current sufficient to burn out the dust to the heating resistor 17 is configured. When the semiconductor flow measurement device detects the accumulation of dust, after the detection of the flow rate is completed, a current is applied to the heating element 17 by a dust removal circuit (not shown), and dust 200 (shown in FIG. Is heated to about several hundred degrees. Dust 200 (not shown)
Is heated to about several hundred degrees, the dust 200 (not shown) is burned off, and the dust 200 (not shown) deposited on the cavity 21 is removed. With such a configuration, it is possible to remove dust accumulated in the cavity 21.

Next, a method of manufacturing the semiconductor flow measuring device of the sixth embodiment will be described. FIG. 21 is a cross-sectional view illustrating a method for manufacturing the thermal flow rate measuring element according to the sixth embodiment in the order of steps. After the insulator layer 14 made of silicon nitride, silicon oxide, or the like is formed on the semiconductor substrate 30, the electrode 20 made of a conductive material and the heating element 17 are patterned and formed, and then the sacrificial layer 120 made of polysilicon or the like is formed. Is deposited, and after patterning the electrode 18 made of a conductive material, a film is formed (step (a)). Further, the insulating layer 13 and the heating element 1 made of a metal such as platinum or a silicide such as W-Si.
6, and an insulator layer 12 is formed (step (b)). T
The sacrifice layer 120 is removed by an etchant such as MAH (tetramethylammonium hydroxide) or KOH to form the cavity 21 (step (c)). With the above-described manufacturing method, it is possible to manufacture a semiconductor flow measurement device capable of detecting and removing dust accumulated in the hollow portion 21.

Embodiment 7 FIG. FIG. 22 is a perspective view showing a semiconductor flow measuring element according to the seventh embodiment, and FIG. 23 is a sectional view thereof. The present embodiment is characterized in that a temperature detecting resistor 150 is provided as a dust detecting element for detecting dust 200 accumulated in the cavity 21 and a dust removing element for removing the accumulated dust 200. In the present embodiment, the temperature sensitive resistor 150 is
1 is provided on the lower surface. When dust accumulates in the hollow portion 21 due to the presence of the temperature-sensitive resistor 150, heat conduction occurs through the dust from the heating element 16 and the temperature-sensitive resistor 150
In order to raise the temperature, the accumulation of dust can be detected. This makes it possible to confirm whether or not a measurement error has occurred. The method for measuring the flow rate is the same as that in the fifth embodiment, and therefore will not be described here. The method for detecting the accumulated dust and the method for removing the accumulated dust are the same as those in the third embodiment, and a description thereof will be omitted.

FIG. 24 is a view showing a method of manufacturing the thermal type flow measuring element according to the seventh embodiment in the order of steps. Insulator layer 1 made of silicon nitride, silicon oxide, etc. on semiconductor substrate 30
4, a temperature-sensitive resistor 150 made of a conductive material is patterned and formed, and then a sacrificial layer 120 made of polysilicon or the like is deposited (step (a)). Next, an insulator layer 13, a heating element 16 made of a metal such as platinum or a silicide such as W-Si, and an insulator layer 12 are formed (step (b)). The sacrifice layer 120 is removed by an etchant such as TMAH (tetramethylammonium hydroxide) or KOH to form a cavity 21 (step (c)).

According to the above-described manufacturing method, it becomes possible to manufacture a semiconductor flow rate measuring device capable of detecting and removing dust accumulated in the hollow portion 21.

Embodiment 8 FIG. FIG. 25 is a perspective view showing a semiconductor flow measurement device according to the eighth embodiment. FIG. 26 is a cross-sectional view of the semiconductor flow measurement device of the eighth embodiment. The present embodiment is characterized in that a temperature sensing resistor 150 is provided as a dust detecting element for detecting dust accumulation, and a heating element 17 is provided as a dust removing element for removing accumulated dust. In this embodiment, the heating element 17 is provided on the temperature-sensitive resistor 150 via the insulator layer 11.

The method for measuring the flow rate is the same as that in the fifth embodiment, and will not be described here. The method for detecting the accumulation of dust is the same as in the seventh embodiment, and a description thereof will be omitted. The method of removing the accumulated dust is the same as that of the sixth embodiment, and thus the description is omitted here.

FIG. 27 is a view showing a method of manufacturing the semiconductor flow measuring device according to the eighth embodiment in the order of steps. Semiconductor substrate 30
An insulator layer 14 made of silicon nitride, silicon oxide, or the like is formed thereon, and a temperature-sensitive resistor 150 made of a conductive material is formed.
After forming the insulator layer 11 and the heating element 17, a sacrificial layer 120 made of polysilicon or the like is deposited (step (a)). Next, an insulator layer 13, a heating element 16 made of a metal such as platinum or a silicide such as W-Si, and an insulator layer 12 are formed (step (b)). TMAH
(Tetramethylammonium hydroxide), K
The sacrificial layer 120 is removed by an etchant such as OH,
The cavity 21 is formed (step (c)).

According to the above-described manufacturing method, it is possible to manufacture a semiconductor flow measuring device capable of detecting the accumulation of dust in the cavity and removing the accumulated dust.

[0063]

According to the semiconductor flow measurement of any one of the first to fourth and sixth and seventh aspects, it is possible to detect dust accumulated in a space that can keep thermal insulation. .

[0064] possible to remove dust deposited in the space so as maintain the thermal insulation of a semiconductor flow measuring device according to any one of apparatus claims 5 and 8 and that Do.

[Brief description of the drawings]

FIG. 1 is a plan view and a cross-sectional view of a semiconductor flow measurement device according to a first embodiment.

FIG. 2 is an explanatory diagram illustrating an example of a specific configuration of a heating element in the semiconductor flow measurement device according to the first embodiment.

FIG. 3 is an explanatory diagram showing a state in which dust is accumulated in the semiconductor flow measurement device of the first embodiment.

FIG. 4 is an explanatory diagram for illustrating a method of manufacturing the semiconductor flow measurement device according to the first embodiment.

FIG. 5 is a plan view and a cross-sectional view of a semiconductor flow measurement device according to a second embodiment.

FIG. 6 is an explanatory diagram showing a state in which dust is deposited in the semiconductor flow measurement device according to the second embodiment.

FIG. 7 is an explanatory diagram for illustrating a method of manufacturing the semiconductor flow measurement device according to the second embodiment.

FIG. 8 shows a plan view and a cross-sectional view of a semiconductor flow measurement device according to a third embodiment.

FIG. 9 is an explanatory diagram showing a state in which dust is accumulated in the semiconductor flow measurement device according to the third embodiment.

FIG. 10 is an explanatory diagram for illustrating a method for manufacturing the semiconductor flow measurement device of the third embodiment.

FIG. 11 shows a plan view and a cross-sectional view of a semiconductor flow measurement device according to a fourth embodiment.

FIG. 12 shows a semiconductor flow measurement device according to a fourth embodiment.
It is an explanatory view for showing the state where dust accumulated.

FIG. 13 is an explanatory diagram for illustrating a method for manufacturing the semiconductor flow measurement device of the fourth embodiment.

FIG. 14 is a perspective view of a semiconductor flow measurement device according to a fifth embodiment.

FIG. 15 is a sectional view of a semiconductor flow measuring device according to a fifth embodiment.

FIG. 16 illustrates a semiconductor flow measuring device according to a fifth embodiment.
FIG. 4 is an explanatory diagram illustrating an example of a specific configuration of a heating element.

FIG. 17 is an explanatory diagram for illustrating the method for manufacturing the semiconductor flow measurement device of the fifth embodiment.

FIG. 18 is a perspective view of a semiconductor flow measurement device according to a sixth embodiment.

FIG. 19 is a sectional view of a semiconductor flow measuring device according to a sixth embodiment.

FIG. 20 illustrates a semiconductor flow measuring device according to a sixth embodiment.
FIG. 4 is an explanatory diagram showing an example of a specific configuration of a heating element for removing dust accumulated in a cavity.

FIG. 21 is an explanatory diagram for illustrating a method for manufacturing the semiconductor flow measurement device of the sixth embodiment.

FIG. 22 is a perspective view of a semiconductor flow measuring device according to a seventh embodiment.

FIG. 23 is a sectional view of a semiconductor flow measuring device according to a seventh embodiment.

FIG. 24 is an explanatory diagram for illustrating the method for manufacturing the semiconductor flow measurement device of the seventh embodiment.

FIG. 25 is a perspective view of a semiconductor flow measurement device according to an eighth embodiment.

FIG. 26 is a sectional view of a semiconductor flow measuring device according to an eighth embodiment.

FIG. 27 is an explanatory diagram for illustrating the method for manufacturing the semiconductor flow measurement device of the eighth embodiment.

FIG. 28 is a sectional view of a conventional semiconductor flow measuring device.

[Explanation of symbols]

11 Insulator layer 12 Insulator layer 1
3 Insulator layer 14 Insulator layer 16 Heating element 1
7 heating element 18 electrode 20 electrode 3
0 semiconductor substrate 31 recess 32 opening 5
DESCRIPTION OF SYMBOLS 1 Resistance element 100 Bridge part 110a Protective film for doping 110b Protective film for doping 1
Reference Signs List 11 impurity layer 120 sacrificial layer 150 temperature-sensitive resistor 2
00 Dust 161 Heating section 162 Lead section 171 Heating section 172 Lead section

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01F 1/68-1/699 G01F 15/12

Claims (8)

(57) [Claims] 1. An apparatus for measuring a flow rate of a fluid by disposing the semiconductor substrate in a fluid, the semiconductor substrate having a recess on a surface thereof, and a space above the semiconductor substrate being provided with thermal insulation from the semiconductor substrate. A heating element disposed in the semiconductor flow rate measuring device capable of measuring the flow rate of the fluid by changing the characteristics of the heating element in accordance with the flow velocity of the surrounding fluid; to detect dust deposited on the extent of the space that gives, on the concave
A first electrode disposed on the bottom side, and a first electrode disposed on a bottom surface of the recess.
A semiconductor flow measurement device comprising a dust detection element comprising a second electrode . 2. A flow of the fluid by placing the fluid
An apparatus for measuring an amount of a semiconductor having a concave portion on a surface.
Through a substrate and a space that provides thermal insulation from the semiconductor substrate.
And a heating element disposed above the recess.
The characteristics of the thermal element change according to the flow velocity of the surrounding fluid
Semiconductor capable of measuring the flow rate of the fluid by
In the body flow measuring device, the thermal insulation
In order to detect dust accumulated in the space, the bottom of the recess is detected.
Equipped with a dust detection element consisting of a temperature-sensitive resistor placed on the surface
A semiconductor flow measurement device. 3. A flow of the fluid by placing the fluid
An apparatus for measuring an amount of a semiconductor having a concave portion on a surface.
Through a substrate and a space that provides thermal insulation from the semiconductor substrate.
And a heating element disposed above the recess.
The characteristics of the thermal element change according to the flow velocity of the surrounding fluid
Semiconductor capable of measuring the flow rate of the fluid by
In the body flow measuring device, the thermal insulation
In order to detect dust that accumulates in the space,
A first electrode disposed on one side, and a first electrode disposed on an outer periphery of the recess.
And a dust detection element comprising a second electrode.
Semiconductor flow rate measuring device to. 4. A flow of the fluid by placing the fluid
An apparatus for measuring an amount of a semiconductor having a concave portion on a surface.
Through a substrate and a space that provides thermal insulation from the semiconductor substrate.
And a heating element disposed above the recess.
The characteristics of the thermal element change according to the flow velocity of the surrounding fluid
Semiconductor capable of measuring the flow rate of the fluid by
In the body flow measuring device, the thermal insulation
In order to detect dust accumulated in the space, the outside of the recess is detected.
Equipped with a dust detection element consisting of a temperature-sensitive resistor
A semiconductor flow measuring device. 5. The method according to claim 5, wherein said fluid is disposed in a fluid.
An apparatus for measuring an amount of a semiconductor having a concave portion on a surface.
Through a substrate and a space that provides thermal insulation from the semiconductor substrate.
And a heating element disposed above the recess.
The characteristics of the thermal element change according to the flow velocity of the surrounding fluid
Semiconductor capable of measuring the flow rate of the fluid by
In the body flow measuring device, in the space providing the thermal insulation
In order to remove dust accumulated on the
A first electrode disposed on the second electrode and a second electrode disposed on a bottom surface of the concave portion.
A semiconductor flow measuring device, comprising: a dust removing element comprising the electrodes described above . 6. An apparatus for measuring a flow rate of a fluid by arranging the semiconductor layer in a fluid, wherein a cavity is provided inside the semiconductor substrate by forming an insulator layer on the semiconductor substrate in a convex shape,
A heating element disposed above the semiconductor substrate via the space of the cavity, wherein the flow rate of the fluid is measured by changing characteristics of the heating element according to the flow velocity of the surrounding fluid. In a possible semiconductor flow measurement device,
In order to detect dust that accumulates in the space that provides the thermal insulation, a first electrode is provided in the space that provides the thermal insulation.
A semiconductor flow measuring device comprising a dust detection element comprising a pole and a second electrode . 7. A flow of the fluid by placing the fluid
An apparatus for measuring an amount, comprising: a semiconductor substrate;
Provide a cavity inside the insulator layer on the substrate by making the insulator layer convex,
Through a space that provides thermal insulation of the cavity.
A heating element disposed above the conductive substrate.
The characteristics of the element may change according to the flow velocity of the surrounding fluid.
Semiconductor capable of measuring the flow rate of the fluid by
In the flow rate measuring device, an empty space sufficient to provide the thermal insulation
In order to detect dust accumulated in the space, the thermal insulation
Equipped with a dust detection element consisting of a temperature sensitive resistor in the space to be given
A semiconductor flow measurement device. 8. The method according to claim 8, wherein said fluid is disposed in a fluid.
An apparatus for measuring an amount , comprising: a semiconductor substrate;
Provide a cavity inside the insulator layer on the substrate by making the insulator layer convex,
Through a space that provides thermal insulation of the cavity.
A heating element disposed above the conductive substrate.
The characteristics of the element may change according to the flow velocity of the surrounding fluid.
Semiconductor capable of measuring the flow rate of the fluid by
In the flow rate measuring device, an empty space sufficient to provide the thermal insulation
In order to remove dust accumulated in the space, the thermal insulation
A first electrode and a second electrode arranged in a given space
A semiconductor flow measuring device comprising a dust removing element comprising: