JP2000286473A - Physical quantity sensor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a diaphragm with a simpler method and to provide a fine and highly integrated physical quantity sensor with new structure by forming a thin film on an underlying substrate having irregularities and using that the thin film takes structure that it floats from the substrate. SOLUTION: A thin film 2 which is partially opened is formed on a silicon substrate 1, and piezoelectric films 4 and 5 taking floating structures are formed on the film with a part buried in the opening part of the thin film as a column. At the time of working SiO2 2 being the thin film on the silicon substrate 1, resist 7 used as a mask forms core of SBT, increases a particle size and makes the film to be dense. The piezoelectric films bring structure formed of the column part 4 buried in the opening part and the floating part 5 floated through a gap 3 with the gap 3. Thus, the physical quantity sensor which can be thinned, can be integrated and has new structure can be manufactured by manufacturing the new diaphragm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a physical quantity sensor for converting a physical quantity such as light, heat, pressure, acceleration and the like into an electric signal and a method of manufacturing the same.

[0002]

2. Description of the Related Art A physical quantity sensor for converting a physical quantity such as light, heat, pressure, acceleration and the like into an electric signal is an indispensable device for input and control of equipment. The principle of converting these physical quantities into electric signals varies depending on each device, but from the structural features of the devices, it can be said that the main function of the physical quantity sensor is concentrated on a diaphragm (diaphragm) structure.

The reason why the function of the physical quantity sensor depends on the diaphragm structure is as follows. Taking a pressure sensor as an example, a conventional pressure sensor contains a diaphragm that is largely displaced in accordance with the pressure in order to efficiently detect the pressure. In the case of an infrared sensor, for example, the heat-sensitive part that senses infrared light has a diaphragm structure that rises from the substrate in order to prevent heat from flowing to the substrate and to reduce the heat capacity of the heat-sensitive part itself and increase sensitivity to infrared light. ing. As described above, it can be said that the functions and performances of the pressure sensor and the infrared sensor depend on the diaphragm in terms of the device structure.

[0004] On the other hand, the conventional method of manufacturing a diaphragm can only be obtained by extremely complicated steps. For example, in a general sensor manufacturing process, a process of manufacturing a diaphragm and a process of bonding the diaphragm to a substrate formed by hollowing out a movable portion of the diaphragm by an electrostatic sealing or an anodic bonding technology are required. And the process is very complicated.

On the other hand, as a method of manufacturing a diaphragm without using these bonding techniques, there is a method of forming a diaphragm by forming a thin film portion in a silicon substrate. In this method, a silicon wafer typically having a thickness of several hundreds of microns is generally etched from the back surface to form a thin film region of several microns. Such a method not only requires a long process time, but also involves problems such as waste of material due to shaving of the Si substrate, difficulty in alignment in a device manufacturing process after forming a thin film region, and the like. .

Further, a drawback common to the two typical diaphragm manufacturing methods described above is that these methods are not suitable for miniaturizing and integrating a sensor device. This is mainly because it is extremely difficult to perform positioning for forming a sensor device in the area of the diaphragm with high accuracy by the conventional method.

In addition, the conventional method of manufacturing a sensor requires a sensor-specific process for forming a diaphragm as exemplified above.
This is a factor that hinders the new possibility of mounting sensors and sensors on the same substrate.

[0008]

As described above, in the conventional physical quantity sensor, the manufacturing process of the diaphragm, which is the structural core of the sensor, is complicated, the efficiency of resource and time utilization is low, and the element is miniaturized. However, it was unsuitable for integration. In addition, the process unique to the sensor was incompatible with the existing LSI process, and closed the possibility of integration of the sensor with the LSI.

The present invention has been made in view of the above background, and has as its object to provide a method of manufacturing a diaphragm by a simpler method, thereby providing a physical quantity sensor having a new structure, The function is intended to be expanded by arranging the sensors two-dimensionally or mixing them with existing LSIs.

[0010]

According to a first aspect of the present invention, a step of selectively forming a mask material on a substrate, a step of removing a predetermined amount of the substrate using the mask material as a mask, a step of removing the substrate and A method of manufacturing a physical quantity sensor, comprising: a step of forming a piezoelectric film on the mask material; a step of removing the mask material; and a step of forming a semiconductor sensor on the piezoelectric film. It is.

According to a second aspect of the present invention, there is provided a physical quantity comprising a substrate having irregularities on the surface, a piezoelectric film formed on the surface of the substrate, and a semiconductor sensor formed on the piezoelectric film. It is a sensor.

That is, the present invention is characterized in that a physical quantity sensor having a new structure is provided by utilizing a structure in which a thin film is formed on an underlying substrate having irregularities and the thin film rises from the substrate. I do.

According to the present invention, a normal
Since the diaphragm structure can be made using only the processes used in LSI, the number of processes is reduced as compared with the conventional sensor manufacturing method, and materials and time are not wasted. This has the effect of making alignment very easy. As a result, the present invention not only provides a physical quantity sensor having a new structure and function, but also facilitates the fabrication of a finer and integrated sensor element than before, and incorporates the sensor element into a part of an integrated circuit. It also gives you the possibility.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a physical quantity sensor having a new structure by utilizing a structure in which a thin film is formed on a base substrate having irregularities and the thin film rises from the substrate. Features. This will be described below with reference to the drawings.

FIG. 1 is a sectional structural view of a physical quantity sensor for detecting pressure according to a first embodiment of the present invention. A thin film 2 (eg, SiO ₂₎ partially opened on a silicon substrate 1
) Is formed thereon, and the piezoelectric film 4 having a floating structure is formed on the portion embedded in the opening of the thin film as a support.
And 5 are formed. A thin film transistor (Thin Film Transistor: TF) is formed on the piezoelectric film by a known method.
T) is formed. Here, silicon substrate 1 and thin film 2
Together, they are called a substrate. A piezoelectric material is a substance in which the value of spontaneous polarization of a crystal changes due to a slight atomic displacement inside the crystal due to an external pressure, and a charge (voltage) is generated on the surface.

Next, a method of manufacturing the physical quantity sensor will be described with reference to the drawings. As shown in FIG.
A thin film 2, for example, SiO ₂ is deposited thereon. Thereafter, the resist 7 which is usually used is patterned by lithography such as ordinary electron beam exposure, and the thin film 2 is processed using the resist 7 as a mask to open a contact hole.

Subsequently, on the substrate shown in FIG. 2, a piezoelectric film, here, for example, SrBi ₂ Ta ₂ O ₉ (SBT) is formed by a metal organic decomposition (MOD) method. In the MOD method, a polycrystalline dielectric film is obtained by applying a MOD solution to a substrate by spin coating or the like, evaporating the solvent in the solution by baking, and performing an oxygen heat treatment at a high temperature of about 800 ° C. . Here, the dielectric is an insulator that does not have conduction electrons and is a substance that causes dielectric polarization due to an external electric field.

At this time, the resist used as a mask when processing SiO ₂ in the present invention (for example, the resist MES-EP2 for KrF was used) acts on the nucleation and growth process of SBT and has a grain size. As shown in FIG. 3, the piezoelectric film is separated from the support portion 4 embedded in the opening and the floating portion 5 that floats through the gap 3 between the thin film 2 as shown in FIG. Resulting in such a structure. The height at which the piezoelectric film rises depends on the thickness of the SBT, the diameter and interval of the contact hole. SBT film thickness
90nm, 150nm, 230nm, contact hole size 0.25
In most cases, a lift of about 20 to 40 nm was observed for each case of 0.5 micron square and 0.5 micron square and 1 micron square. As an exception, when the SBT film thickness is 90 nm, the contact hole size is 0.5 μm square, and the spacing is 1 μm, the SBT film portion between the contact holes bends downward, and the thin film 2 in FIG.
Since the and the piezoelectric body (floating portion) 5 came into contact with each other, a floating structure could not be obtained. The MOD here
Although a ferroelectric film formation method was used, any manufacturing method such as a sol-gel method, a sputtering method, or a CVD method may be used. Here, a ferroelectric substance is a substance whose spontaneous polarization possessed by a crystal can be reversed by an external electric field, whereby the electric field-polarization characteristic shows a hysteresis characteristic.

In the floating structure of the piezoelectric film as shown in FIG. 3, for example, a carbon film is used in place of the thin film 2 and the resist 7 in FIG. 2, and a piezoelectric film is formed thereon by a known method. An existing aerial wiring method may be adopted, for example, by manufacturing by volatilizing carbon by oxygen heat treatment.

A thin film transistor 6 is formed on a piezoelectric film having a floating structure manufactured as shown in FIG.
By manufacturing the pressure sensor, the structure of the pressure sensor as shown in FIG. 1 is obtained. At this time, for example, a silicon nitride film may be inserted as a reaction prevention film between the piezoelectric body and the thin film transistor. Note that the step of heating the diffusion layer of the thin film transistor and the step of heat treatment for removing the resist may be the same.

The principle of pressure detection by the physical quantity sensor shown in FIG. 1 will be described with reference to FIG. Here, the floating portion 5 of the piezoelectric film
It is assumed that pressure is applied to the thin film transistor manufactured above as shown in FIG. At this time, the floating portion 5 of the piezoelectric film has a structure movable by the gap 3 and can be easily displaced. When the piezoelectric film is displaced, distortion is generated inside the piezoelectric film, and electric charges corresponding to the direction of displacement and the crystal orientation of the piezoelectric material are induced on the surface of the piezoelectric film. The electric charge induced on the surface of the piezoelectric film acts on the electric charge distribution in the channel region of the adjacent thin film transistor, and changes the threshold voltage of the transistor in short. It can be converted into an electric signal and detected with high sensitivity.

As a preliminary experiment, a MISFET (Metal-Insulator-Semiconduct
In a device in which an insulator film portion of a field effect transistor (or field effect transistor) is made of a piezoelectric material, transistor characteristics when distortion was applied to the transistor were measured. FIG. 5 shows the results of the experiment, in which the threshold voltage of the transistor shifts in the negative direction by about 1.8 V with the application of pressure, and the threshold value control of the transistor using the piezoelectric surface charge is possible in principle. It was shown that. Considering this experimental result, the charge induced on the surface when pressure is applied to the piezoelectric film is as shown in FIG.

In the physical quantity sensor of FIG. 1, since the displacement at the atomic level can be converted into a large electric signal by utilizing the piezoelectric effect, the pressure can be detected with high sensitivity and efficiency.

In the above-described embodiment, the pressure detection method using the piezoelectric effect is used. However, in the present invention, the following physical quantity sensor can be configured using a floating film structure. The piezoelectric elements 4 and 5 of FIG. 1 are more general insulator films, and the thin film transistor 6 of FIG. 1 is a piezoresistive element to constitute a piezoresistive physical quantity sensor as shown in FIG. Here, the thin film transistor 6 and the piezoresistive element are called a semiconductor sensor.

Further, the thin film 2 of FIG. 1 is composed of an insulating film, a lower electrode is provided on the insulating film, the piezoelectric members 4 and 5 are more general insulating films, and an upper electrode is formed on the insulating film. By configuring, a capacitance type physical quantity sensor as shown in FIG. 7 is configured.

In any of these embodiments, the physical quantity to be detected is not limited to pressure, and acceleration can be detected. The part of a conventional physical quantity sensor that senses the physical quantity
The (sensing part) was required to be in the form of a diaphragm (diaphragm) so that it could easily be displaced by an external force, and it was essential for existing physical quantity sensors to form a diaphragm structure. A feature of the present invention is that, in this diaphragm manufacturing method, as shown in FIG. 3, an insulator film is formed on a base substrate having irregularities, and a structure is employed in which the film rises from the substrate. It is in. The advantages of the diaphragm manufacturing method of the present invention over the conventional method will be described below.

FIGS. 8 and 9 show a typical diaphragm structure according to the conventional method. The conventional method is described for each example, the problems are pointed out, and the effectiveness of the present invention with respect to the conventional method is explained.

In FIG. 8, the silicon substrate 11 is etched from the back of the substrate with an alkaline solution or the like to form a groove 12.
To produce Thus, the thickness of the Si substrate is reduced to about several microns, and the diaphragm 13 is formed. Then, a pressure-sensitive element such as a piezoresistor is manufactured in accordance with the diaphragm to constitute a physical quantity sensor.

In such a method for manufacturing a diaphragm,
Since a large amount of Si substrate is etched from the back surface of the substrate, process time, an etchant, and Si raw materials are wasted.
Furthermore, since elements such as piezoresistors are configured by fitting to thinly processed parts, positioning is not easy, and for example, it is difficult to make a fine and highly integrated physical quantity sensor in terms of alignment accuracy. .

On the other hand, in the manufacturing method of the present invention, since the diaphragm is formed from the substrate surface side, there is no waste.
Since there is no need to etch the Si substrate and there is no problem in positioning the element with respect to the diaphragm, it is possible in principle to manufacture a physical quantity sensor that is finer and more integrated than in the past. Also, the number of steps is smaller than in the conventional method.

In the conventional manufacturing method shown in FIG. 9, a diaphragm is formed from the substrate surface side. A hole 19 for etching is opened in the etching mask film 16, the lower support film 15 is etched through this hole to produce a cavity 18, and the upper support film 17 is formed on the etching mask film 16. 20.

In this diaphragm manufacturing method, the problems of unnecessary etching and difficulty in alignment as in the example of FIG. 8 are solved. However, this method has a multi-layer structure, a large number of processes, and an etching mask film 16.
The process conditions are severely limited, as represented by the fact that the etching selectivity of the lower support film 15 to the substrate must be high. Further, in the step of forming the upper support film 17 on the etching mask film 16 after the formation of the cavity 18, it is considered difficult to form the film continuously on the etching hole 19 so as not to fall into the hole. In short, the process of forming the upper support film after the formation of the cavity through the etching hole in the process of forming the diaphragm makes the method itself difficult to realize. Further, in the method of manufacturing the diaphragm as shown in FIG. 9, a laminated structure of dissimilar materials, such as the lower support film 15, the etching mask film 16, and the upper support film 17, is inevitable. Occurrence of structural defects (cracks) near the interface of each layer is expected due to the difference in expansion coefficient, and the structure shown in FIG. 9 also has a problem in this respect.

On the other hand, in the manufacturing method of this embodiment,
Since the diaphragm structure is completed when the piezoelectric film is formed in FIG. 3, the diaphragm structure can be reliably obtained with a smaller number of processes than in FIG. Further, in the manufacturing method of the present embodiment, unlike the conventional manufacturing method of FIG. 9, since the constituent elements of the diaphragm are a single substance, they do not contain structural weakness due to contact of different kinds of substances. .

As described above, in the physical quantity sensor according to the present embodiment, the diaphragm for detecting the physical quantity such as pressure and acceleration is structurally stronger with a smaller number of processes than the conventional method, and is further positioned. It is possible to manufacture in an easy way. Further, a high-performance physical quantity sensor based on a new principle and structure using the piezoelectric effect can be provided.

FIG. 10 is a sectional view of a physical quantity sensor for detecting infrared rays according to the second embodiment. Silicon substrate 2
1, a partially opened insulating film 22 (for example, SiO 2
₂ ) and a lower electrode 23 are formed, and a pyroelectric film 24 having a floating structure is formed on the lower electrode 23 by using a portion embedded in the opening of the insulating film as a support. An upper electrode 25 and an infrared absorbing film 26 are manufactured on the pyroelectric film. Here, a pyroelectric substance is a substance that generates an electric charge (voltage) on its surface due to a change in the spontaneous polarization of the crystal caused by an atomic displacement inside the crystal due to a change in temperature.

Next, a method for manufacturing the physical quantity sensor will be described with reference to the drawings. First, as shown in FIG. 11, an insulating film (for example, SiO ₂ ) 22 and a lower electrode 23 are successively deposited on a silicon substrate 21. As the lower electrode 23, an electrode material having oxidation resistance, for example, a platinum group element such as Pt, Ir, Ru, or an oxide thereof, such as IrO ₂ or RuO ₂
And so on.

Further, as shown in FIG. 12, the insulating film (for example, SiO ₂ ) is
22, the lower electrode 23 is etched to form a hole for burying the pyroelectric film.

Subsequently, a pyroelectric thin film is formed on the substrate by, for example, the MOD method. The resist 29 left on the lower electrode 23 increases the particle diameter and densifies the film, and as shown in FIG. 13, a pillar 27 in which a pyroelectric film is embedded in the opening, A structure including a floating portion 28 floating between the electrode 23 and the electrode 23 via the gap 31 is provided. The floating structure of the pyroelectric film may be realized by a known method as in the description of the first embodiment.

On the pyroelectric film 24 shown in FIG.
5. The infrared absorbing film 26 is formed continuously. Upper electrode 2
Reference numeral 5 uses the same material as the lower electrode 23, and uses a material such as NiCr as the conventional infrared absorbing film. After that, the upper electrode 25 and the infrared absorbing film 26 are processed by a normal technique to obtain the structure of the physical quantity sensor as shown in FIG.

The principle of infrared detection by the physical quantity sensor shown in FIG. 10 will be described with reference to FIG. FIG. 14 illustrates a heat-sensitive portion of the physical quantity sensor of FIG. 10 extracted and drawn. When infrared light enters the infrared absorbing film 26, the temperature of the incident portion rises due to the thermal energy of the infrared light, and the temperature of the pyroelectric body 24 rises. At this time, as shown in FIG. 10, since the heat-sensitive portion has a diaphragm structure, the outflow of heat to the substrate is suppressed,
Its heat capacity is small. Therefore, it is possible to detect infrared rays with high sensitivity. When the temperature of the pyroelectric body 24 increases, electric charges are generated on the surface of the pyroelectric body 24 according to the temperature and the crystal orientation of the pyroelectric body 24 as shown in FIG. By detecting the newly generated charge as, for example, a transient current, a sensor that converts infrared rays into an electric signal and detects the electric signal is configured.

In the above embodiment, the method of detecting the charge of the pyroelectric body as a transient current of the circuit has been described. However, if a thin film transistor similar to that of the first embodiment is formed instead of the upper electrode 25 in FIG. It becomes possible to detect the incidence of infrared light as a change in the threshold value of the transistor.
(FIG. 15).

In the conventional physical quantity sensor, a portion for receiving infrared rays (heat-sensitive portion) has a diaphragm (diaphragm) structure as if it were raised from the substrate in order to prevent diffusion of heat to the substrate and to reduce heat capacity. Is required. A feature of the present invention is that, in the method of manufacturing a diaphragm, as shown in FIG. 13, an insulating film is formed on a base substrate having irregularities and a structure is employed in which the film rises from the substrate. It is in. The advantages of the diaphragm manufacturing method of the present invention over the conventional method will be described below.

FIG. 16 shows a typical diaphragm structure according to the conventional method. Pyroelectric body 37 sandwiched between upper and lower electrodes
Are fixed to a ceramics substrate 32 with an adhesive 33 based on polyimides 34 and 35. Hereinafter, the manufacturing process of the pyroelectric sensor of FIG. 16 will be described with reference to the drawings.

First, a pyroelectric body 37 is formed on a substrate (for example, MgO) 39, and the pyroelectric body 37 is processed as shown in FIG. Subsequently, a polyimide film 35 is deposited on this substrate,
By forming a contact hole in the polyimide film 35 and forming an electrode 36 for the pyroelectric body, a structure as shown in FIG. 18 is obtained.

Further, the polyimide film 3 is formed on the substrate shown in FIG.
4 to obtain a structure as shown in FIG. Next, FIG.
The substrate is turned upside down and fixed to the ceramics substrate 32 with an adhesive 33. As a result, a structure as shown in FIG. 20 is obtained.

Thereafter, the substrate 39 is entirely removed by etching, and an infrared absorbing electrode 38 is formed on the pyroelectric film 37 to obtain a physical quantity sensor having a structure as shown in FIG.

The conventional method for manufacturing a physical quantity sensor described above is a general method described in a textbook, but requires a complicated process and wastes material and process time. Furthermore, it is not suitable in principle for producing a fine and integrated sensor element.

As a method of manufacturing a physical quantity sensor, there is a method of manufacturing a diaphragm on a Si substrate, but as described with reference to FIG. 8 of the first embodiment, a thin film is formed by etching the Si substrate from the back surface of the substrate. Most methods are used, and as described in detail in the first embodiment, materials and steps are wasted, and alignment is difficult.

On the other hand, in the method of manufacturing the physical quantity sensor according to the present embodiment, the number of processes is smaller than that of the conventional method because the manufacturing method of the diaphragm is simpler. A highly integrated physical quantity sensor is provided.

In the present embodiment, the description has been limited to the detection of infrared rays. However, since the pyroelectric body generates surface-induced charges in accordance with the temperature change of the substance itself, factors other than the partial incidence of infrared rays are considered. In principle, it is also possible to detect a temperature change by heat conduction, for example, a temperature change of an object in contact with the heat-sensitive part by heat conduction.

The third embodiment relates to a circuit configuration of a sensor in which three-terminal type physical quantity sensors are two-dimensionally arranged. FIG.
Reference numeral 1 denotes the thin film transistor type physical quantity sensor of FIG. 1 in the first embodiment or FIG. 15 in the second embodiment.
2 is a circuit diagram in which the thin film transistor type physical quantity sensors are two-dimensionally arranged.

By arranging the physical quantity sensors two-dimensionally as shown in FIG. 21, it is possible to read the shape of the surface of an object such as a fingerprint. Further, application as a pointing device in a conventional personal computer is also possible. If a three-terminal pressure sensor is two-dimensionally arranged on a substrate that is flexible against external force, for example, a resin substrate, it can be used as a motion sensor that senses the movement of the human body in virtual reality.

On the other hand, if the physical quantity sensors are two-dimensionally arranged as shown in FIG. 21, application as an infrared image sensor becomes possible. At this time, the infrared detection sensitivity is improved by making each infrared detecting element independent for each cell and suppressing the diffusion of heat in the in-plane direction.

The two-dimensional array of sensors as shown in FIG. 21 is not limited to the three-terminal type physical quantity sensor according to the first or second embodiment, but is also applicable to a known three-terminal type sensor element. It is possible.

The fourth embodiment relates to a manufacturing method in which the sensor according to the first or second embodiment is monolithically arranged on a conventional LSI substrate. The present invention, as already described,
Since a diaphragm can be formed by a process only from a substrate surface side and a process that is used even in a normal LSI, and a physical quantity sensor can be configured, it is easy to mount a sensor on an existing LSI.

The mixed mounting of the sensor and the LSI will be described with reference to two examples. First, in the first example, an application in which an infrared image sensor and a peripheral circuit used in an infrared imaging device are mixedly mounted on the same substrate can be considered. Specifically, a physical quantity sensor array in which the physical quantity sensors shown in the third embodiment are two-dimensionally arranged, a pyroelectric current detection circuit detected by the sensor, an image processing circuit, a storage circuit, and the like are replaced by the same Si. Mixed on the substrate. As a result, a more compact infrared imaging device with more functions than before can be realized. As a second example, an application in which a pressure sensor and a peripheral circuit are mixedly mounted can be considered. Functions such as shape recognition, shape storage, reference, etc. in one chip by combining a circuit that detects threshold value change, resistance change, capacitance change, etc. detected by the pressure sensor, and a memory circuit, control circuit, etc. Can be aggregated.

The feature of this embodiment resides in that the physical quantity sensor and the LSI according to the present invention, which can be manufactured by the same process as the LSI, are integrated on one chip to achieve function integration. It is not limited to.

[0058]

As described above in detail, a physical quantity sensor having a new structure can be manufactured by the new method for manufacturing a diaphragm according to the present invention. In principle, these sensors can be manufactured using a simpler process than conventional sensors, require fewer processes, and can be miniaturized and integrated. Sensors can be easily mixed on the same substrate, and function expansion beyond the role of a single sensor can be expected.

[Brief description of the drawings]

FIG. 1 is a sectional view of a physical quantity sensor according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a manufacturing process of the physical quantity sensor according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a manufacturing process of the physical quantity sensor according to the first embodiment of the present invention.

FIG. 4 is a principle diagram of pressure detection in the physical quantity sensor according to the first embodiment of the present invention.

FIG. 5 is a principle diagram of pressure detection in the physical quantity sensor according to the first embodiment of the present invention.

FIG. 6 is a sectional view of the physical quantity sensor according to the first embodiment of the present invention.

FIG. 7 is a sectional view of the physical quantity sensor according to the first embodiment of the present invention.

FIG. 8 is a sectional view of a diaphragm in a conventional physical quantity sensor.

FIG. 9 is a sectional view of a diaphragm in a conventional physical quantity sensor.

FIG. 10 is a sectional view of a physical quantity sensor according to a second embodiment of the present invention.

FIG. 11 is a sectional view showing a manufacturing process of the physical quantity sensor according to the second embodiment of the present invention.

FIG. 12 is a sectional view showing a manufacturing process of the physical quantity sensor according to the second embodiment of the present invention.

FIG. 13 is a sectional view showing a manufacturing process of the physical quantity sensor according to the second embodiment of the present invention.

FIG. 14 is a principle diagram of infrared detection in a physical quantity sensor according to a second embodiment of the present invention.

FIG. 15 is a sectional view (TFT type) of a physical quantity sensor according to a second embodiment of the present invention.

FIG. 16 is a cross-sectional view of a conventional physical quantity sensor.

FIG. 17 is a sectional view showing a manufacturing process of a conventional physical quantity sensor.

FIG. 18 is a sectional view showing a manufacturing process of a conventional physical quantity sensor.

FIG. 19 is a sectional view showing a manufacturing process of a conventional physical quantity sensor.

FIG. 20 is a sectional view showing a manufacturing process of a conventional physical quantity sensor.

FIG. 21 is a conceptual diagram showing a two-dimensional arrangement of physical quantity sensors according to a third embodiment of the present invention.

[Explanation of symbols]

 1, 11, 14, 21 Si substrate 2 Thin film 3, 31 Gap 4 Piezoelectric body (post) 5 Piezoelectric body (floating part) 6 Thin film transistor 7, 29 Resist 8 Piezoresistive element 9, 23 Lower electrode 10, 25 Upper electrode 12 Etching grooves 13, 20 Diaphragm part 15 Lower support film 16 Etching mask film 17 Upper support film 18 Cavity 19 Etching hole 20 Diaphragm part 22 Insulating film 24 Pyroelectric film 26 Infrared absorbing film 27 Pyroelectric film (post) 28 Pyroelectric film (floating part) 30 Post groove 32 Ceramic substrate 33 Adhesive 34, 35 Polyimide 36 Readout electrode 37 Pyroelectric body 38 Absorbing electrode 39 Substrate 40 Physical quantity sensor (transistor type)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akira Toriumi 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 2F055 AA40 BB20 CC02 DD04 DD05 DD09 DD19 EE14 EE23 EE25 FF43 GG01 GG11 2G065 AB02 BA13 BA34 BC11 BC33 DA20 4M112 AA01 BA01 BA03 BA07 CA03 CA16 DA02 EA02 EA06 EA20

Claims (2)

[Claims] A step of selectively forming a mask material on a substrate; a step of removing the substrate by a predetermined amount using the mask material as a mask; and forming a piezoelectric film on the substrate and the mask material. Performing the step of: removing the mask material; and forming a semiconductor sensor on the piezoelectric film. 2. A physical quantity sensor comprising: a substrate having irregularities on its surface; a piezoelectric film formed on the surface of the substrate; and a semiconductor sensor formed on the piezoelectric film.