JP2000077729A - Manufacturing method of sensor - Google Patents

Abstract

(57) [Problem] To provide a method for manufacturing a sensor having high sensor sensitivity and high mechanical strength of a device during a manufacturing process. SOLUTION: A step of forming a supporting insulating film 53 on a semiconductor substrate 7, a step of forming a protective film 55 thereon,
Removing a portion of the protective film 55 to expose the supporting insulating film 53 to form the thin film supporting portion 43; and removing a portion of the semiconductor substrate 7 below the supporting insulating film 53 to remove the supporting insulating film 53. The method includes at least a step of forming the cavity region 22 in the lower part and a step of forming the separation groove by removing the thin-film supporting portion 43 by dry etching. During the manufacturing process,
The membrane region above the cavity region 22 is a thin film support 43
It is strongly supported by.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sensor, and more particularly to a method for manufacturing a semiconductor sensor using semiconductor micromachining technology.

[0002]

2. Description of the Related Art As a semiconductor sensor using a semiconductor micromachining technology, an infrared sensor, a physical quantity sensor, and the like are known. An infrared sensor will be described as an example of these semiconductor sensors. As shown in the plan view of FIG. 22A, a typical conventional infrared sensor includes light receiving units 29 and 31 that convert infrared light into heat and light receiving units 29 and 3.
1, the connecting portions 35 and 37, the substrate 130 supporting the connecting portions 35 and 37, the light receiving portions 29 and 31, and the substrate 130.
And a thermocouple 131 for detecting a temperature difference between the two. The light receiving sections 29 and 31 are in contact with the substrate 130 via the connection sections 35 and 37, respectively, and have no other thermal contact.
The thermocouple 131 includes a p-type polysilicon resistance wiring 132, an n-type polysilicon resistance wiring 133, and an aluminum wiring 134.

FIG. 22B is a sectional view taken along the line FF in FIG. 22A. A support insulating film 143 is formed over the single crystal silicon substrate 130, and the support insulating film 143 is formed.
A cavity region 26 in which a crystal plane 150 is exposed is formed below the surface. A p-type polysilicon resistance wiring 132 is arranged on the supporting insulating film 143, and an interlayer insulating film 144 is formed on the p-type polysilicon resistance wiring 132. An aluminum wiring 134 is arranged on the interlayer insulating film 144,
A protective film 145 is formed on the aluminum wiring 134. Further thereon, infrared absorption films 146 and 147 for converting infrared light into heat are formed, respectively. Anisotropic etching holes 141 and 142 are selectively formed in each layer (143 to 145) formed on the cavity region 26. The connection portion 35 and the light receiving portions 29 and 31 are formed separately from the substrate 130 by the anisotropic etching holes 141 and 142 and the cavity region 26.

The infrared rays incident on the infrared absorbing films 146 and 147 are converted into heat, and the heat is converted into heat.
The temperature of the hot junction 148 is transmitted to the hot junction 148 disposed below the hot junction 47 and the temperature of the hot junction 148 rises. Therefore, the hot junction 148
And a cold junction 149, a temperature difference is generated, and a thermoelectromotive force is generated by the Seebeck effect.

FIG. 2 shows a method of manufacturing this infrared sensor.
This will be described with reference to FIGS. (B) in each figure
The drawing is a cross-sectional configuration diagram along the FF direction in FIG.

(A) First, as shown in FIG.
A supporting insulating film 143 is formed on the entire surface of the substrate. On the supporting insulating film 143, a polysilicon film to which impurities are not added (non-doped polysilicon film) is formed. Then, p-type impurities and n-type impurities are selectively ion-implanted, and the polysilicon film (doped polysilicon film) to which these impurities are added is patterned to form polysilicon resistance wirings 132 and 133. An interlayer insulating film 144 is formed on the entire surface of the polysilicon resistance wirings 132 and 133. A contact hole is formed in the portion of the interlayer insulating film 144 where the hot junction 148 and the cold contact 149 are formed, and an aluminum wiring 134 is formed on the interlayer insulating film 144. A protective film 145 is formed on the entire surface of the aluminum wiring 134.
Further, infrared absorbing films 146 and 147 are selectively formed thereon.

(B) Next, as shown in FIG.
The anisotropic etching holes 141 and 142 are selectively formed in each layer (143 to 145) formed on the substrate 0 to expose the silicon substrate 130.

(C) Next, a silicon etchant is introduced through the anisotropic etching holes 141 and 142 shown in FIG. 24, and the substrate 130 is anisotropically etched. As a result, a cavity 26 as shown in FIG. 22 is formed, and the infrared sensor is completed.

[0009]

In order to improve the sensitivity of the sensor, it is necessary to increase the thermal resistance between the light receiving sections 29, 31 and the substrate 130. To increase the thermal resistance, the connecting portions 35 and 37 need to be thin or thin. However, by making the connection portions 35 and 37 thinner or thinner, the mechanical strength of the connection portions 35 and 37 decreases, and the substrate 130
The device is damaged by an etching process using a chemical solution such as anisotropic etching described above, a water washing process thereafter, and a water pressure or vibration applied at the time of chip division or the like, thereby causing a reduction in manufacturing yield. On the other hand, if the connection portions 35 and 37 are made thick or thick enough not to damage the device, the sensitivity of the sensor is reduced.

[0010] These problems also apply to a dynamic quantity sensor or the like having a similar structure.

The present invention has been made in order to solve such a problem, and an object of the present invention is to manufacture a sensor which has high mechanical strength of a device during a manufacturing process and can prevent destruction during the manufacturing process. Is to provide a way.

Still another object of the present invention is to reduce the size (width) of the connection portion and to reduce the thickness of the thin film forming the connection portion, thereby realizing a high-sensitivity sensor with a high production yield. It is an object of the present invention to provide a method for manufacturing a sensor which can be used.

It is still another object of the present invention to provide a method of manufacturing an infrared sensor having a high manufacturing yield and high detection sensitivity.

Still another object of the present invention is to provide a method for manufacturing a physical quantity sensor having a high production yield and high detection sensitivity.

Still another object of the present invention is to provide a method of manufacturing a sensor having high processing accuracy and a small number of manufacturing steps.

Still another object of the present invention is to provide a manufacturing method that can easily realize a membrane structure required for a sensor and that does not break the membrane structure during a manufacturing process.

[0017]

In order to solve such a problem, a first feature of the present invention is that (a) a step of forming a supporting insulating film on a semiconductor substrate; and (b) a supporting insulating film. (C) removing a portion of the protective film to expose a portion of the supporting insulating film to form a thin-film supporting portion; and (d) forming a thin film supporting portion on the lower portion of the supporting insulating film. Removing a portion of the semiconductor substrate, and exposing a portion of the lower portion of the supporting insulating film,
(E) forming a separation groove by removing the thin-film supporting portion by dry etching. Here, the steps (b) to (d) do not necessarily have to be performed in this order. For example,
Since the step (d) can also be performed by etching from the back surface of the substrate, between the steps (a) and (b),
It may be performed between the step (b) and the step (c).

The thin film supporting portion is finally removed in the step (e) and becomes a separation groove, that is, a so-called “dummy” portion. By the above step (d), a cavity is formed below the supporting insulating film, and the supporting insulating film and the laminated structure thereon become a so-called "membrane". The membrane is supported by the thin film supporting portion. ing. The membrane support has the freedom to select its support area independently of the final structure of the sensor. Therefore, according to the first aspect of the present invention, it is easy to increase the mechanical strength for supporting the membrane, so that the sensor is resistant to mechanical shock during the manufacturing process. “Mechanical impact” refers to a mechanical force applied to a membrane during wet etching or washing with water after wet etching. Finally, by removing the thin film support in the step (e) to form a separation groove, a structure in which the membrane is finally supported by the thin support can be realized. No water washing or the like is required in the dry etching in the step (e), and no mechanical shock is applied in this step. Therefore, it is possible to prevent the sensor from being damaged during the manufacturing process.

According to a second feature of the present invention, before the step of forming the protective film, the method further includes a step of forming a temperature detecting element on the supporting insulating film and a step of forming an interlayer insulating film. Forming an infrared absorbing film on the protective film after forming the protective film.

According to a second feature of the present invention, a temperature detecting element, an interlayer insulating film, a protective film and an infrared absorbing film are formed on a supporting insulating film, and a part of the semiconductor substrate below the supporting insulating film is formed. Even if it is removed and the hollow portion is provided below the supporting insulating film, the membrane having the laminated structure can be firmly supported by the supporting insulating film. Therefore, the infrared sensor can be prevented from being damaged during the manufacturing process, and
Finally, the required membrane support can be made thinner,
The sensitivity of the infrared sensor is improved.

A third feature of the present invention is that the method for manufacturing a sensor further includes a step of forming a physical quantity measurement sensor section on the supporting insulating film before the step of forming the protective film.

According to the third feature of the present invention, even if a part of the semiconductor substrate below the supporting insulating film is removed and a cavity is provided below the supporting insulating film, the supporting insulating film is removed. A mechanical measurement section and a protective film are formed on the substrate, and the membrane having a laminated structure of these can be firmly supported by the supporting insulating film. Therefore, the physical quantity sensor can be prevented from being damaged during the manufacturing process, and the final structure may have a thin structure, so that the sensitivity of the physical quantity sensor is improved.

A fourth feature of the present invention is a method for manufacturing a sensor in which the supporting insulating film is a silicon nitride film and the protective film is a silicon oxide film.

According to the fourth feature of the present invention, it is easy to select an etching gas or an etching solution that increases the etching selectivity between the silicon nitride film and the silicon oxide film. Therefore, in the step (c) of the first feature, if an etching gas or an etching solution is selected so that the etching rate of the silicon oxide film is higher than the etching rate of the silicon nitride film, the silicon nitride film forming the thin film supporting portion is selected. Can function as an etching stopper layer. That is, since the end point of the etching in the step (c) can be automatically determined, highly accurate etching can be performed. Conversely, if an etching gas with a high etching rate of the silicon nitride film is selected as the dry etching gas in the step (e) of the first feature, only the silicon nitride film is selected in a self-aligned manner without using any mask. Separation grooves can be easily formed by etching. Therefore, according to the fourth aspect of the present invention, in addition to the points described in the first aspect, it is possible to manufacture the sensor with high accuracy and simple steps.

A fifth feature of the present invention is a method for manufacturing a sensor in which a protective film is formed after anisotropic etching holes for etching a semiconductor substrate are formed in a part of a supporting insulating film. .

According to a fifth aspect of the present invention, a portion of the semiconductor substrate below the supporting insulating film is removed through the anisotropic etching hole to expose a portion of the lower portion of the supporting insulating film. Can be. In addition, anisotropic etching holes having a minimum area required for anisotropic etching can be formed, and the remaining portion can be used as a thin film support. Then, since the support insulating film may be removed by utilizing the selectivity of etching between the protective film and the support insulating film, a structure resistant to mechanical shock during the manufacturing process can be easily realized.

[0027]

According to the present invention, it is possible to provide a method for manufacturing a sensor in which the mechanical strength of a device during a manufacturing process is high and destruction during the manufacturing process can be prevented.

According to the present invention, the dimension (width) of the connection portion is also provided.
And the thickness of the thin film forming the connecting portion can be reduced, and a sensor manufacturing method that can realize a high-sensitivity sensor with a high manufacturing yield can be provided.

Further, according to the present invention, it is possible to provide a method of manufacturing an infrared sensor having a high production yield and high detection sensitivity.

Further, according to the present invention, it is possible to provide a method of manufacturing a dynamic quantity sensor having a high production yield and a high selection sensitivity.

Further, according to the present invention, the processing accuracy is high,
In addition, it is possible to provide a sensor manufacturing method with a small number of manufacturing steps.

Further, according to the present invention, it is possible to easily realize a membrane structure necessary for the sensor and to easily realize a manufacturing method in which the membrane structure is not damaged during the manufacturing process.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of the present invention will be described below. FIG. 1A is a plan view of an infrared sensor according to the first embodiment of the present invention. As shown in FIG. 1A, the infrared sensor according to the first embodiment of the present invention includes light receiving units 28 and 30 that convert infrared light into heat, and a connection unit 13 that supports the light receiving units 28 and 30. , The substrate 7 supporting the connecting portion 13 and the light receiving portion 2
Temperature detecting element 4 for detecting a temperature difference between 8, 30 and substrate 7
7 to 49. The light receiving sections 28 and 30 contact the substrate 7 via the connection section 13 and have no other thermal contact. As the temperature detecting elements 47 to 49, for example, a thermocouple, a bolometer, a pyroelectric element, or the like is used. Here, a case where a thermocouple using the Seebeck effect is used will be described. The case where a bolometer is used will be described in a second embodiment. The thermocouple includes, for example, a p-type polysilicon resistance wiring 47, an n-type polysilicon resistance wiring 48, and an aluminum wiring 49. If the Seebeck effect is remarkable, polysilicon resistance wirings 47 and 48
Of course, other metals may be used instead of One end of each of the p-type polysilicon resistance wiring 47 and the n-type polysilicon resistance wiring 48 is arranged in the light receiving units 28 and 30, and the other end is arranged on the substrate 7 via the connection part 13. The aluminum wiring 49 connects the end of the p-type polysilicon resistance wiring 47 and the end of the n-type polysilicon resistance wiring 48. The connection points between the polysilicon resistance wirings 47 and 48 and the aluminum wiring 49 are connected to the hot junctions 51 and
On the substrate 7, the cold junction 52 is formed.

FIG. 1 (b) is a cross-sectional configuration diagram along the AA direction of FIG. 1 (a). As shown in FIG.
On the (00) plane single-crystal silicon substrate 7, a supporting insulating film 53 having corrosion resistance to a silicon etchant is formed. The supporting insulating film 53 is, for example, a silicon nitride film (Si
₃ N ₄ film) is used. Below the supporting insulating film 53, (1
The cavity region 22 in which the crystal plane 65 of the (10) plane is exposed is formed. On the supporting insulating film 53, a p for forming a thermocouple is formed.
Type polysilicon resistance wiring 47 is arranged. FIG.
Although not shown in (b), n-type polysilicon resistance wiring 48
Are also arranged on the supporting insulating film 53. The thickness of the polysilicon resistance wirings 47 and 48 is, for example, 3
50 nm, and electrically supported on the substrate 7 by the supporting insulating film 53.
Insulated from Polysilicon resistance wiring 47, 48
An interlayer insulating film 54 having a thickness of 300 to 600 nm is formed thereon. As the interlayer insulating film 54, for example, a silicon oxide film (SiO ₂ film) is used. On the interlayer insulating film 54, an aluminum wiring 49 forming a thermocouple is arranged. The aluminum wiring 49 is electrically insulated from the polysilicon resistance wirings 47 and 48 by the interlayer insulating film 54. In the interlayer insulating film 54, a p-type polysilicon resistance wire 47 and an aluminum wire 49 are electrically connected, and a contact hole for forming a hot contact 51 and a cold contact 52 is formed. Although not shown in FIG. 1B, similar contact holes are formed in the n-type polysilicon resistance wiring 48. On the aluminum wiring 49, for example, a thickness of 50
A protective film 55 of about 0 nm is formed. Protective film 55
For example, a silicon oxide film is used. On the protective film 55, gold black (Au-Blac) for selectively converting infrared rays into heat is used.
k), infrared absorbing films 61, 62 of Ni-Cr (an alloy of nickel and chromium), amorphous silicon, etc. are formed to form light receiving portions 28, 30, respectively.
Then, each layer (53 to 5) formed on the substrate 7 is formed.
5) penetrating anisotropic etching hole 40 and separation groove 4
5 is selectively formed on the cavity region 22. The width of the separation groove 45 is, for example, about 5 to 10 μm. The first and second light receiving portions 28 and 30 and the connection portion 13 are formed separately from the substrate 13 by the anisotropic etching hole 40, the separation groove 45 and the cavity region 22.

Next, the operation of the infrared sensor having such a configuration will be described. First and second light receiving sections 2
The infrared rays incident on 8, 30 are absorbed by the infrared absorbing films 61, 62 and converted into heat. The converted heat is transmitted to the hot junction 51 disposed below the infrared absorbing films 61 and 62, and the temperature of the hot junction 51 rises. Therefore, a temperature difference occurs between the hot junction 51 and the cold junction 52, and a thermoelectromotive force is generated between the hot junction 51 and the cold junction 52 by the Seebeck effect. This thermoelectromotive force can be extracted from the terminals 63 and 64 to the outside of the sensor.

Next, a method of manufacturing the infrared sensor according to the first embodiment of the present invention will be described with reference to FIGS. In each of the drawings, (a) is a plan configuration diagram, and (b) is a cross-sectional configuration diagram along the AA direction of (a).

(A) First, as shown in FIG. 2, a silicon nitride film as a supporting insulating film 53 is formed on the entire surface of a substrate 7 having a main surface having a (100) plane orientation by a CVD method.
A mask such as a photoresist having a window at a portion where the anisotropic etching hole 40 is formed is formed on the supporting insulating film 53 by a photolithography method. Using this mask,
The supporting insulating film 53 is selectively removed by etching such as the IE method, and anisotropic etching holes 40 are formed as shown in FIG.

(B) Next, the supporting insulating film 5 is formed by the CVD method.
Then, a non-doped polysilicon film is formed on the entire surface.
A mask for ion implantation such as a photoresist is formed using a photolithography method, and boron (
A p-type impurity ion such as ¹¹ B ⁺ ) is selectively implanted into the non-doped polysilicon film. Although not shown to selectively ion-implanting an n-type impurity ions such as phosphorus ⁽³¹ P ⁺⁾ in the same manner for the region where n-type polysilicon resistor wire 48 is formed in FIG. 3 (b). The impurity ions implanted by the heat treatment are activated to form an impurity-added polysilicon film (doped polysilicon film). An etching mask is formed using a photolithography method. Using this etching mask, the polysilicon resistance wires 47 and 48 are patterned by etching such as RIE as shown in FIG. Note that patterning may be performed first, and then ion implantation may be performed. Next, an interlayer insulating film 54 is formed on the entire surface of the polysilicon resistance wirings 47 and 48 by the CVD method. A mask having a window at a portion where the hot junction 51 and the cold junction 52 are formed is formed on the interlayer insulating film 54 by photolithography. Using this mask, the interlayer insulating film 54 is selectively removed by the RIE method to form a contact hole, and the polysilicon resistance wirings 47 and 48 in this portion are exposed. An aluminum film is formed on the entire surface of the interlayer insulating film 54 by a sputtering method, a vacuum evaporation method, or the like. At this time, the contact hole is filled with the aluminum film. Then, an etching mask is formed on the aluminum film by a photolithography method, and the aluminum wiring 49 is patterned into a plane shape as shown in FIG. 3A by etching such as RIE using the etching mask. Thereafter, a silicon oxide film as a protective film 55 is formed on the entire surface of the aluminum wiring 49 by the CVD method. Further thereon, the infrared absorbing film 61 is selectively provided in a region where the first and second light receiving portions are formed.
62 is formed. For this selective formation, a lift-off method may be used. It is needless to say that a film may be formed on the entire surface first and then patterned.

(C) Next, an etching mask is formed on the laminated structure shown in FIG. 3 by photolithography. Using this etching mask, the interlayer insulating film 54 and the protective film 55 are selectively removed by etching such as RIE. For example, CHF ₃ / CO as an etching gas
Is performed, the selectivity between the silicon oxide film as the interlayer insulating film 54 and the protective film 55 and the silicon nitride film as the supporting insulating film 53 can be 15 or more, so that the supporting insulating film 53 is an etching stopper. Work as Alternatively, ammonium fluoride (NH ₄ F) and hydrofluoric acid (HF)
The interlayer insulating film 54 and the protective film 55 may be etched using an oxide etchant such as a mixture of the above. Since the oxide film etching solution hardly etches the silicon nitride film, the etching selectivity can be regarded as almost infinite. Therefore, the silicon substrate 7 is exposed in the portion where the anisotropic etching hole 40 is opened first, but the silicon nitride film (supporting insulating film) 53 is exposed in other portions. The exposed portion of the silicon nitride film becomes the thin film support portion 43.

(D) Next, the substrate 7 exposed through the anisotropic etching holes 40 is subjected to anisotropic etching of the substrate 7 by introducing an etching solution such as KOH or hydrazine. At this time, since the supporting insulating film 53 has corrosion resistance to the etchant, only the silicon substrate 7 can be etched. As a result, a crystal plane ((1) plane) different from the plane orientation ((100) plane) of the main surface of the silicon substrate.
10) The cavity region 22 in which the surface 65 is exposed is formed.
The laminated structure above the cavity region 22 becomes a so-called “membrane”. In the state shown in FIG.
Are supported by the connecting portion 13 and the supporting insulating film 53 of the thin film supporting portion 43. After the anisotropic etching, it is sufficiently washed. In particular, the inside of the cavity 22 has a small anisotropic etching hole 4.
Open it up and water goes in and out, so do it carefully. Also,
The selective formation of the infrared absorbing films 61 and 62 by the lift-off method in the step (b) may be performed after the formation of the hollow region 22.

(E) Next, dry etching is performed to selectively remove the supporting insulating film 53 of the thin film supporting portion 43.
The separation groove 45 shown in FIG. At this time, the separation groove 4
By performing dry etching using CF ₄ or the like as an etching gas without using a mask for selectively etching the supporting insulating film 53 to be 5 without affecting other parts of the device, Consistently with thin film support 43
Only the silicon nitride film (support insulating film) 53 can be removed. That is, since the etching selectivity of the silicon nitride film 53 with respect to the uppermost infrared absorption films 61 and 62 and the silicon oxide films (interlayer insulating film and protective film) 54 and 55 is large, only the silicon nitride film 53 can be used without using a mask. Can be selectively removed. For example, the ratio (selection ratio) between the etching rates of gold black as the infrared absorption films 61 and 62 and the silicon nitride film 53 is almost infinite, and the selection between the silicon oxide film and the silicon nitride film 53 as the protection film 55 is made. The ratio is around 5. Also,
Since it is not a process of forming a pattern but a simple removal process, the etching accuracy may be low. Through the above steps, the infrared sensor shown in FIG. 1 is completed.

In the above description, although the description of the step of removing each photoresist is omitted, each photoresist is removed using an oxygen plasma treatment, a sulfuric acid (H ₂ SO ₄ ) treatment, a resist stripper, and the like. Washed with water.

As described above, in the first embodiment, the light receiving portions 28 and 30 are anisotropically formed on the silicon substrate 7 while being firmly supported by the connecting portion 13 and the supporting insulating film 53 of the thin film supporting portion 43. Performs processes with high risk of damage to devices, such as etching with chemicals such as etching, photoresist removal with chemicals, and water washing after these processes. The supporting insulating film 53 of the thin film supporting portion 43 supporting the thin films 28 and 30 is removed by dry etching with little mechanical impact, and the separation groove 45 is opened. Further, a mask such as a photoresist is not required in the dry etching for forming the separation groove. Therefore, a treatment with a chemical solution required for removing the photoresist and a subsequent washing step are unnecessary, and no mechanical impact is generated in the separation groove step. As described above, since the light receiving portions 28 and 30 after the formation of the cavity region 22 are supported by the connection portion 13 and the thin film support portion 43 until almost immediately before the final step, the water pressure applied to the membrane portion during a series of steps of manufacturing the sensor is increased. Sufficient mechanical strength against vibration, vibration, etc. can be obtained. Also, the thin film support 43
Since the etching removal does not require precision, it may be performed after the chip is cut. In this manner, breakage of the device due to cutting water at the time of chip cutting can be prevented. Further, the mechanical strength of the connecting portion 13 does not need to consider the damage in the manufacturing process.
3 can be made thin or thin to such an extent that it will not be damaged in a normal use environment. For example, although the thickness of the interlayer insulating film 54 is described to be 300 to 600 nm, it is possible to select a smaller thickness. Therefore, the thermal resistance of the connection portion 13 is increased, and the sensitivity of detecting infrared rays is improved.

(First Modification) In the first modification, the first modification
The method for manufacturing an infrared sensor according to the embodiment includes a step of forming a polycrystalline silicon film 72 between the supporting insulating film 53 and the single-crystal silicon substrate 7. The structure of the completed infrared sensor is substantially similar to the structure shown in FIG. The operation is basically the same as the operation of the sensor having the structure shown in FIG. Hereinafter, a method of manufacturing the infrared sensor according to the first modified example will be described with reference to FIGS. In each figure, (b) is BB of (a).
FIG.

(A) As shown in FIG. 5, a polycrystalline silicon film 72 having a thickness of about 100 to 350 nm is formed on the entire surface of the single crystal silicon substrate 7 by the CVD method. A predetermined mask such as a photoresist is formed by a photolithography method. Using this mask, a rectangular polycrystalline silicon film 72 is formed by etching such as RIE. CV
The supporting insulating film 53 is formed on the polycrystalline silicon film 72 by the D method.
Is formed on the entire surface. A predetermined mask is formed by photolithography, and as shown in FIG. 5A, silicon nitride on the four corners of the rectangular polycrystalline silicon film 72 is etched by RIE or the like using this mask. The film 53 is selectively removed to form an anisotropic etching hole 40 of, for example, about 30 to 40 μm square.
The polycrystalline silicon film is exposed in the anisotropic etching hole 40.

(B) Next, as shown in FIG. 6, in the same manner as in the first embodiment, the polysilicon resistance wirings 47 and 48 and the silicon oxide film as the interlayer insulating film 54 are formed on the supporting insulating film 53. , An aluminum wiring 49, a silicon oxide film as a protective film 55, and an infrared absorbing film are sequentially arranged and formed. FIG.
(B) does not show the infrared absorbing film, the hot junction and the cold junction of the thermocouple, but it is needless to say that they are formed in the same manner as in the first embodiment. Further, in the first embodiment, the light receiving section is divided into two, but here it is integrally formed in a square shape. Therefore, the infrared absorbing film is also formed integrally. Further, light receiving portion 9 is formed inside polycrystalline silicon film 72 and is formed such that anisotropic etching holes 40 are arranged on the outer periphery of light receiving portion 9. FIG. 6 shows a state in which the above steps have been completed.

(C) Next, an etching mask is formed on the laminated structure shown in FIG. 7 by photolithography. Using this etching mask, the interlayer insulating film 54 and the protective film 55 are selectively removed by etching such as RIE. Therefore, the anisotropic etching hole 40
The silicon substrate 7 is exposed in the portion where the hole is opened, but the silicon nitride film (supporting insulating film) 53 is exposed in other portions. The exposed portion of the silicon nitride film becomes the thin film support portion 43.
A silicon etchant is introduced into the polycrystalline silicon film 72 exposed by the anisotropic etching holes 40. At this time, since the etching rate with respect to the silicon etchant to be used is higher in polycrystalline silicon than in monocrystalline silicon, the polycrystalline silicon film is first removed by etching, and then the monocrystalline silicon substrate 7 is etched. Therefore, a flat cavity is formed in the region where the polycrystalline silicon film 72 is formed, and anisotropic etching of the single crystal silicon substrate 7 is started from the entire cavity region on the flat plate. As a result, a cavity region 22 exposing a predetermined crystal plane 65 similar to that of the first embodiment is formed.
The light receiving section 9 is supported by the connecting section 13 and the supporting insulating film 53 of the thin film supporting section 43.

(D) Next, dry etching using an etching gas such as CF ₄ is performed to selectively remove the supporting insulating film 53 of the thin film supporting portion 43 to form a separation groove 45.
After the above steps are completed, the infrared sensor shown in FIG. 8 is completed.

In the method of manufacturing the infrared sensor according to the first modification, the silicon etchant first removes the polycrystalline silicon film 72 by etching to form a thin plate-shaped cavity, and this thin plate-shaped cavity is formed. , Anisotropic etching of the single crystal silicon substrate 7 can be performed.
That is, the anisotropic etching hole 40 may be formed at a location, size and shape necessary for etching the polycrystalline silicon film 72 which is easier to etch than the single crystal silicon 7. Need not be considered. That is, as shown in FIG. 4, when the anisotropic etching of the single crystal silicon substrate 7 is started immediately from the anisotropic etching hole 40, it is necessary to consider the plane orientation of the substrate 7 in order to form a square cavity. There is. That is, it is necessary to stop the etching at the crystal plane (111) during the anisotropic etching of the substrate 7. For this reason,
As shown in FIG. 1, an anisotropic etching hole 40 was required in a long band-like region rising to the left between the oblique sides of the light receiving unit 28 and the oblique sides of the light receiving unit 30. However, in the first modification,
An etching hole 40 necessary for etching the polycrystalline silicon film 72 may be formed, and the long strip-shaped region as shown in FIG. 1 is not required. That is, in the first modification, the location, size, and shape of the anisotropic etching hole can be freely selected. Here, the case where anisotropic etching holes are formed at four corners of the cavity region 22 has been shown.
That is, since it is not necessary to form the anisotropic etching hole 40 having a large area as shown in FIG. 1, the area of the light receiving section 9 can be made large.

(Second Modification) In a second modification, anisotropic etching of the substrate 7 for forming the cavity region 22 is performed from the back surface of the substrate 7 with reference to FIGS.
This will be described with reference to FIG. Similar to the sensor shown in FIG. 1, the structure of the completed infrared sensor has a substantially similar structure, and the operation is basically the same. In each figure, (b) is a step cross-sectional view along the CC direction of (a). The step portion in (a) is indicated by cc in (b).

(A) As shown in FIG. 9, a silicon nitride film as a supporting insulating film 53, polysilicon resistance wirings 47 and 48, a silicon oxide film as an interlayer insulating film 54, an aluminum wiring 49, A silicon oxide film as a protective film 55 and an infrared absorption film 56 are arranged and formed. However, no anisotropic etching holes are formed in the support insulating film 53. A back surface etching prevention film 73 is formed on the entire back surface of the substrate 7 by the CVD method. The back surface etching prevention film 73 is, for example, a silicon oxide film (S
iO ₂ film) is used. A predetermined mask is formed by a photolithography method, and an anisotropic etching hole 44 is formed in the back surface etching prevention film 73 by etching such as RIE using the mask.

(B) As shown in FIG. 10, an etching mask is formed on the laminated structure shown in FIG. 9 by using a photolithography method. RI using this etching mask
The interlayer insulating film 45 and the protective film 55 are selectively removed by etching such as E method. Therefore, it is possible to form the thin film support portion 43 in which the silicon nitride film (support insulating film) 53 is exposed. A silicon etchant is introduced from the back surface of the substrate 7 to the back surface of the substrate 7 using the etching prevention film 73 as a mask. As a result, the silicon substrate 7 under the light receiving section 9 and the connection section 13 is removed, and the cavity region 23 is formed. At this time, the light receiving section 9 is connected to the connecting section 13 and the supporting insulating film 53.
Is supported all around it.

(C) Dry etching is performed using an etching gas such as CF ₄ to remove the supporting insulating film 53 of the thin film supporting portion 43 in a self-aligned manner. After the above steps are completed, the infrared sensor shown in FIG. 11 is completed.

In the second modification, since the anisotropic etching of the substrate 7 is performed from the back surface, it is not necessary to form anisotropic etching holes on the surface of the substrate. Therefore, the cavity region 23
The entire outer periphery of the formed light receiving section 9 can be supported by the connection section 13 and the supporting insulating film 53. Since the entire outer periphery of the light receiving unit 9 can be supported, the mechanical strength of the device during the manufacturing process increases. The step of forming the hollow region 23 may be performed immediately after the formation of the supporting insulating film 53 or before the formation of the protective film 55.

(Second Embodiment) In the first embodiment of the present invention, a thermocouple is used as a temperature detecting element constituting an infrared sensor. In addition, an infrared sensor using a bolometer or a pyroelectric element is used. Is similarly applicable.
In the second embodiment of the present invention, a case where a bolometer is used as a temperature detecting element will be described.

As shown in FIG. 12A, the infrared sensor according to the second embodiment has a light receiving section 10 for converting infrared rays into heat, and connecting sections 36 and 38 for supporting the light receiving section 10, and connecting sections 36, The substrate 7 supports the substrate 38 and titanium wires 91 and 92 for outputting a temperature change of the light receiving section 10 to the outside of the sensor as an electric signal. The light receiving section 10 and the connection sections 36 and 38 are formed separately from the substrate 7 by anisotropic etching holes 41 and 42 and separation grooves 98. The light receiving unit 10 is connected to the substrate 7 only through the connection units 36 and 38.
And no other thermal contact. Although not shown in FIG. 12A, the light receiving unit 10 has an infrared absorbing film for converting incident infrared light into heat and a bolometer material film. The titanium wiring is composed of titanium wirings 91 and 92, each having one end connected to the bolometer material film and extending to the outside of the sensor via the connection portion.

FIG. 12B is a sectional view taken along line DD of FIG. 12A. As shown in FIG. 12B, a support insulating film 53 having corrosion resistance to a silicon etchant is formed on the single crystal silicon substrate 7. As the support insulating film 53, for example, a silicon nitride film (Si ₃ N ₄ film) is used. In the substrate 7 below the supporting insulating film 53, a cavity region 24 in which a crystal plane different from the surface of the substrate 7 is formed is formed. Titanium wirings 91 and 92 are formed on the supporting insulating film 53.
Is arranged. The titanium wirings 91 and 92 are electrically insulated from the substrate 7 by the supporting insulating film 53. A silicon oxide film as an interlayer insulating film 54 is formed on the titanium wires 91 and 92. A bolometer material film 60 is formed on the interlayer insulating film 54 in a region where the light receiving unit 10 is formed. The bolometer material film 60 is electrically insulated from the titanium wirings 91 and 92 by the interlayer insulating film 54.
In the interlayer insulating film 54, contact holes for electrically connecting the bolometer material film 60 and the titanium wirings 91 and 92 are selectively formed. As the bolometer material film 60, for example, vanadium oxide, polycrystalline silicon, platinum, or the like is used. The protective film 5 is formed on the bolometer material film 60.
A silicon oxide film as No. 5 is formed. On the protective film 55, an infrared absorbing film 57
Are formed. Then, the anisotropic etching hole 4 penetrating each layer (53 to 55) formed on the cavity region 24 is formed.
1, 42 and a separation groove 98 are selectively formed.
The light receiving portion 10 and the connection portions 36 and 38 are formed separately from the substrate 7 by the anisotropic etching holes 41 and 42, the separation groove 98 and the cavity region 24.

The infrared light incident on the infrared absorbing film 57 is absorbed by this film and converted into heat. The converted heat is applied to the bolometer material film 6 disposed below the infrared absorption film 57.
0, the temperature of the bolometer material film 60 rises.
The resistance value of the bolometer material film 60 changes due to the temperature rise. The change in the resistance value is determined by using titanium wires 91 and 92.
Is detected by flowing a current through the bolometer material film 60 using

Next, a method of manufacturing an infrared sensor according to the second embodiment will be described with reference to FIGS. Here, in each drawing, (b) is a cross-sectional configuration diagram in the DD direction of (a).

(A) First, as shown in FIG. 13, a polycrystalline silicon film 7 is formed on a single crystal silicon substrate 7 by CVD.
5 is formed on the entire surface. A mask having a predetermined shape is formed by photolithography, and R
The rectangular polycrystalline silicon film 75 is patterned by etching such as the IE method. A silicon nitride film as a supporting insulating film 53 is formed on the entire surface of the polycrystalline silicon film 75 by the CVD method. A predetermined etching mask is formed by photolithography, and RIE is performed using this mask.
The silicon nitride film 53 is removed by etching such as a method, and anisotropic etching holes 41 and 42 are selectively formed. As a result, the polycrystalline silicon film is exposed in the anisotropic etching holes 41 and 42.

(B) A titanium (Ti) film is formed on the entire surface of the supporting insulating film 53 by a sputtering method or a vacuum evaporation method. A predetermined mask is formed by photolithography, and etching such as RIE is performed using this mask to pattern the titanium wirings 91 and 92 as shown in FIG. A silicon oxide film as an interlayer insulating film 54 is formed on the entire surface of the titanium wirings 91 and 92 by a CVD method. A predetermined mask is formed by a photolithography method, and etching such as RIE is performed using the mask to form titanium masks 91 and 92 disposed on the sides 87 and 89 of the rectangular region constituting the light receiving unit 10. The interlayer insulating film 54 is selectively removed to form a contact hole. As a result, titanium wirings 91 and 92 are exposed in the contact holes. A bolometer material film 60 is formed on the entire surface of the interlayer insulating film 54. A predetermined etching mask is formed by photolithography, and etching such as RIE is performed using the mask to pattern the bolometer material film 60 disposed in the light receiving unit 10. The bolometer material film 60 thus formed is in electrical contact with the titanium wirings 91 and 92 via the contact holes. CV
A silicon oxide film as a protective film 55 is formed on the entire surface of the bolometer material film 60 by Method D. Further, an infrared absorbing film 57 is selectively formed in a region of the light receiving section 10 on the protective film 55. For this selective formation, a lift-off method may be used. Alternatively, after an infrared absorbing film is formed on the entire surface, patterning may be performed by photolithography and RIE.

(C) Next, as shown in FIG. 15, a predetermined etching mask is formed by photolithography, and using this mask, a silicon oxide film as an interlayer insulating film 54 and a protective film 55 in predetermined regions is formed. Only those portions are selectively etched and removed. For example, the silicon oxide films 54 and 55 may be selectively removed with a mixed solution of NH ₄ F / HF that makes the etching selectivity with the silicon nitride film almost infinite. Alternatively, if the RIE method using CHF ₃ / CO as an etching gas is performed, the selectivity between the silicon oxide film as the interlayer insulating film 54 and the protective film 55 and the silicon nitride film as the supporting insulating film 53 can be 15 or more. The support insulating film 53 functions as an etching stopper. Therefore, the polycrystalline silicon film 75 is exposed in the portion where the anisotropic etching holes 41 and 42 are formed first, but the silicon nitride film (support insulating film) 53 is exposed in other portions. The exposed portion of the silicon nitride film becomes the thin film support 93.

(D) Next, the anisotropic etching holes 41, 4
An anisotropic silicon etchant is introduced into the exposed portion of the polycrystalline silicon film 75 in the portion 2. As in the case of the first modification of the first embodiment, the silicon etching liquid first etches the polycrystalline silicon film 75, and then etches the single crystal silicon substrate 7. Therefore, anisotropic etching of substrate 7 is started from the entire region where polycrystalline silicon film 75 is formed. As a result, the cavity region 24 exposing a crystal plane 65 different from the surface of the substrate 7 is formed. In the state shown in FIG. 16, the connection portions 36 and 38 and the support insulating film 53 of the thin film support portion 93 support the light receiving portion 10.

(E) Next, dry etching is performed to selectively remove the supporting insulating film 53 of the thin film supporting portion 93.
A separation groove 98 as shown in FIG. At this time, CF ₄
By performing dry etching using such as an etching gas, only the supporting insulating film 53 of the thin film supporting portion 98 can be removed in a self-aligned manner without affecting other parts of the device. That is, when CF ₄ is used as an etching gas, the etching selectivity of the silicon nitride film 53 to the uppermost infrared absorbing film 57 and silicon oxide films (interlayer insulating film and protective film) 54 and 55 is almost infinite and about 5, respectively. Therefore, only the silicon nitride film 53 can be selectively removed without using a mask. Also, the etching accuracy may be low because it is a simple removal process instead of a pattern formation process. After the above steps are completed, the infrared sensor shown in FIG. 12 is completed.

As described above, also in the infrared sensor using the bolometer material, the light receiving section 10 is connected to the connecting section 3.
While supporting the substrates 6 and 38 and the thin film support 93, anisotropic etching of the substrate, subsequent cleaning, chip splitting and other steps that may cause damage to the device are performed, and then the thin film support 98 is removed. By performing the process, the mechanical strength of the device during the manufacturing process can be kept high. In the step of removing the thin film support 98, C
By performing dry etching using an etching gas of F _4, etc., without giving mechanical impact, it is possible to selectively remove the thin film support 93. Also, the separation groove 9
In the dry etching for forming 8, a mask such as a photoresist is not required. Therefore, a treatment with a chemical solution accompanying the removal of the photoresist and a subsequent washing step are not required, and no mechanical impact force is generated in the separation groove step. Conventionally, the connecting portions 36 and 38 have to be made thick or thick with a mechanical strength enough to avoid such a breakage in the manufacturing process. According to the second embodiment of the present invention, there is no need to consider the possibility of breakage during the manufacturing process.
38 only needs to have mechanical strength not to be damaged in the use environment. Therefore, the shapes of the connecting portions 36 and 38 can be made thinner and thinner than in the past.
For this reason, the thermal resistance of the connection portions 36 and 38 increases, and the sensitivity of the infrared sensor using the bolometer material improves.

(Third Embodiment) In the first and second embodiments, the infrared sensor has been described. However, the manufacturing method of the sensor according to the present invention is not limited to the infrared sensor. The same can be applied to a method of manufacturing a mechanical quantity sensor such as an angular velocity sensor. Third
In the embodiment, a method of manufacturing a flow sensor will be described as a representative of various physical quantity sensors.

The flow rate sensor according to the third embodiment comprises:
As shown in FIG. 17A, the heating elements 94 and 95, the temperature measuring resistors 96 and 97, the heating elements 94 and 95, and the temperature measuring resistor 9
6, a heating element wiring 100 for heating the fluid, a temperature-measuring resistance wiring 98 for measuring the temperature of the fluid,
99. For example, platinum (Pt) is used for the heating element wiring 100 and the temperature measuring resistance wirings 98 and 99.

FIG. 17 (b) is a cross-sectional configuration diagram along the EE direction of FIG. 17 (a). As shown in FIG. 17B, a support insulating film 53 having corrosion resistance to a silicon etchant is formed on the single crystal silicon substrate 7. The supporting insulating film 53 is, for example, a silicon nitride film (Si
₃ N ₄ film) is used. Below the supporting insulating film 53, a cavity region 25 in which a crystal plane different from the surface of the substrate 7 is exposed is formed. The heating element wiring 100 is formed on the supporting insulating film 53.
Also, temperature measuring resistance wires 98 and 99 are formed. Further, a protective film 55 is formed thereon. Protective film 55
For example, a silicon oxide film (SiO ₂ film) is used. Then, anisotropic etching holes 101 and 102 and an isolation groove 111 penetrating through the supporting insulating film 53 and the protective film 55 formed on the substrate 7 are selectively formed on the cavity region 25. Cavity region 25, anisotropic etching holes 101,
The heating pair parts 94 and 95 and the temperature measuring resistance parts 96 and 97 are formed separately from the substrate 7 by the separation groove 111 and the separation groove 111.

Next, when a predetermined current is applied to the heating element wiring 100 and the heating elements 94 and 95 are controlled at a certain high temperature, a certain amount of heat of the heating elements 94 and 95 is released.
4 and 95, the temperatures of the temperature measuring resistance portions 96 and 97 are controlled to be lower than those of the heating elements 94 and 95. In this state, when the fluid moves from the temperature measuring resistor section 96 to the temperature measuring resistor section 97, the temperature measuring resistor section 96 on the upstream side is cooled by the fluid to lower the temperature. On the other hand, in the downstream temperature measuring resistor section 97, heat conduction from the heating elements 94 and 95 is promoted by using a fluid flow as a medium, and the temperature rises. Therefore, the temperature measuring resistor section 9
A temperature difference occurs between the temperature measuring resistor 6 and the resistance temperature measuring unit 97. By incorporating the temperature measuring resistor sections 96 and 97 having the temperature difference into the Wheatstone bridge circuit, the temperature difference can be converted into a voltage, and a voltage output according to the flow rate of the fluid can be obtained.

Next, a method of manufacturing the flow sensor according to the third embodiment will be described with reference to FIGS. In each of the drawings, (b) is a cross-sectional configuration diagram along the EE direction of (a).

(A) First, as shown in FIG. 18, a silicon nitride film as a supporting insulating film 53 is formed on the entire surface of a single crystal silicon substrate 7 by the CVD method. A predetermined etching mask is formed by photolithography, and etching such as RIE is performed using this mask to selectively form anisotropic etching holes 101 and 102. The substrate 7 is exposed at the portions of the anisotropic etching holes 101 and 102. The supporting insulating film 53 is formed by sputtering or vacuum evaporation.
A platinum film is formed on the substrate. A predetermined mask is formed by photolithography, and etching such as RIE is performed using the mask to pattern the heating element wiring 100 and the temperature measurement resistance wiring 98 and 99.

(B) Next, as shown in FIG. 19, the heating element wiring 100 and the temperature-measuring resistance wiring 98, 99 are formed by the CVD method.
A silicon oxide film as a protective film 55 is formed on the entire surface. An etching mask having a window in a predetermined region is formed by photolithography, and the protective film 55 is selectively removed by etching such as RIE using this mask. Then, the anisotropic etching holes 101, 10
The silicon substrate 7 is exposed in the portion where the holes 2 are opened, but the silicon nitride film (supporting insulating film) 53 is exposed in other portions.
The exposed portion of the silicon nitride film becomes the thin film support portion 110.

(C) Next, anisotropic etching holes 101,
An etching solution such as KOH or hydrazine is introduced into the exposed silicon substrate 7 at 102 to perform anisotropic etching of the silicon substrate 7. As a result, a cavity region 25 that has a crystal plane different from the surface of the substrate 7 is formed.
At this time, the supporting insulating film 53 is not etched because it has corrosion resistance to the etchant. Therefore, the heat generating parts 94 and 95 and the temperature measuring resistance parts 96 and 97 are connected to each other by the supporting insulating film 53 of the thin film supporting part 110.

(D) Next, dry etching is performed to selectively remove the supporting insulating film 53 of the thin film supporting portion 110, and a separation groove 111 as shown in FIG. 17 is opened. At this time, dry etching using CF ₄ or the like as an etching gas is performed without using a mask for performing selective etching, so that the thin film supporting portion can be selectively formed without affecting other parts of the device. The supporting insulating film 53 of 110 can be removed. That is, if CF ₄ is used, a large etching selectivity of the silicon nitride film 53 with respect to the silicon oxide film as the protective film 55 can be obtained, so that only the silicon nitride film 53 is selectively removed without using a mask. it can.
In addition, since the process is not a process of forming a pattern but a simple process of removing a film, the etching accuracy may be low. Through the above steps, the flow sensor shown in FIG. 17 is completed.

As described above, also in the flow rate sensor, the anisotropy of the substrate is obtained in a state where the heating elements 94 and 95 and the temperature measuring resistance sections 96 and 97 are connected to each other by the supporting insulating film 53 of the thin film supporting section 110. By using a manufacturing method of performing a process that may damage the device such as etching, subsequent cleaning, and chip splitting, and then selectively removing the supporting insulating film 53 of the thin film supporting portion 110 by dry etching, The same effects as those of the first and second embodiments can be obtained. That is, the mechanical strength of the heating elements 94 and 95 and the temperature measuring resistors 96 and 97 during the manufacturing process can be kept high. Further, in the step of selectively removing the supporting insulating film 53 of the thin film supporting portion 110, the heating elements 94 and 95 and the temperature measuring resistance sections 96 and 97 are performed by performing dry etching using an etching gas such as CF _4. Can selectively remove the supporting insulating film 53 of the thin film supporting portion 93 without receiving a mechanical shock. Further, in the dry etching for forming the separation groove 111, a mask such as a photoresist is not required. For this reason, treatment with a chemical solution accompanying the removal of the photoresist and a subsequent washing step are not required,
No mechanical impact is generated in this separation groove process. Conventionally,
The heating elements 94 and 95 and the resistance temperature detectors 96 and 97 are required to have sufficient mechanical strength to prevent such damage in consideration of the damage in the manufacturing process, and have to be thick or thick. Was. The third aspect of the present invention described above
By using the manufacturing method according to the embodiment, it is not necessary to consider the damage in the manufacturing process, and it is only necessary to have a mechanical strength that is not damaged in the use environment. In other words, the heating element portion 9 which is thinner and thinner than in the related art.
4 and 95 and the resistance temperature measuring portions 96 and 97 can be formed. If it can be formed thin and thin, the heat resistance of the heating elements 94 and 95 and the temperature measuring resistance sections 96 and 97 will be high. The higher the thermal resistance, the higher the sensitivity of the flow sensor.

(Other Embodiments) As described above, the present invention has been described with reference to the first to third embodiments.
The discussion and drawings forming part of this disclosure should not be understood as limiting this invention. From this disclosure, various alternative embodiments, examples, and operation techniques will be apparent to those skilled in the art.

For example, in the first to third embodiments described above, a silicon nitride film is used as the thin film support portion and a silicon oxide film is used as the interlayer insulating and film protective film. The film and the silicon oxide film may be used interchangeably, or the same material may be used. When the same material is used, if the thickness of the protective film is made larger than the thickness of the thin film support portion, the thickness of the protective film is reduced by dry etching, but finally, only the support insulating film of the thin film support portion is removed. Can be removed. Further, as the supporting insulating film, in addition to the silicon nitride film (Si ₃ N ₄ ), alumina (Al ₂ O ₃ )
Other insulating films may be used. Further, various insulating films such as a BSG film, a PSG film, a BPSG film, and a polyimide film can be used as the protective film.

Further, by removing the thin film supporting portion by isotropic etching instead of anisotropic etching, the silicon nitride film under the connecting portion can be removed, and the connecting portion can be made thinner. be able to. If the connection portion can be formed thin, the thermal resistance of the connection portion can be increased.

Further, the semiconductor substrate is not limited to a silicon substrate. Ge may be used, or a compound semiconductor such as GaAs may be used.

Further, a method of manufacturing a single sensor has been described. However, a plurality of sensors may be formed in a matrix on the same silicon substrate, and a switch circuit and an amplifier circuit for sensor outputs may be formed simultaneously. It does not matter. A case in which a plurality of infrared sensors are formed and a switch circuit for outputs from these infrared sensors is formed simultaneously will be described with reference to FIG.

Infrared sensors having output terminals 63 and 64 are arranged in a matrix. The terminals 63 of all the infrared sensors are connected to the second output 124, respectively. The terminals 64 of all the infrared sensors are X
It is connected to the first output 125 via a gate transistor and a Y-gate transistor, respectively. The gate electrode of the X gate transistor connected to the infrared sensor arranged in the X ₁ column is connected to the X ₁ coordinate input 126. That is, the gate electrodes of the X gate transistors connected to the infrared sensors arranged in the X _n column are connected to the X _n coordinate input. Similarly, the gate electrode of the Y gate transistor connected to the infrared sensor arranged in the Y ₁ row is connected to the Y ₁ coordinate input 128. That is,
The gate electrode of the Y gate transistor connected to the infrared sensor arranged in the Y _m row is connected to the Y _m coordinate input.

When it is desired to output a signal from the infrared sensor disposed at the coordinates (n, m), the Xn coordinate input is set to a high level ("H"). Next, the Ym coordinate input is set to a high level (“H”). Then, the X gate transistor 11 connected to the infrared sensor arranged at the coordinates (n, m)
6, 118, 120, and 122 and the Y gate transistors 117, 119, 121, and 123 are turned on, and the terminal 64 of the infrared sensor disposed at the coordinates (n, m) is connected to the first terminal.
Output 125. Therefore, by changing the input of the coordinates, it is possible to randomly access the infrared sensor to be output.

As described above, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the matters specifying the invention described in the claims that are reasonable from this disclosure.

[Brief description of the drawings]

FIG. 1A is a plan view of an infrared sensor according to a first embodiment of the present invention, and FIG.
It is sectional drawing along AA of (a).

FIG. 2A is a plan view showing a manufacturing process of the infrared sensor according to the first embodiment of the present invention.
FIG. 2B is a cross-sectional configuration view along AA in FIG. 2A (part 1).

FIG. 3A is a plan view showing a manufacturing process of the infrared sensor according to the first embodiment of the present invention.
FIG. 3B is a cross-sectional view taken along the line AA of FIG.

FIG. 4A is a plan view showing a manufacturing process of the infrared sensor according to the first embodiment of the present invention.
FIG. 4B is a cross-sectional configuration diagram along AA in FIG. 4A (part 3).

FIG. 5 (a) shows a first embodiment of the first embodiment of the present invention.
FIG. 5B is a cross-sectional view taken along a line BB in FIG. 5A, showing a manufacturing process of the infrared sensor according to the modified example (Part 1).

FIG. 6 (a) shows a first embodiment of the first embodiment of the present invention.
FIG. 6B is a cross-sectional view taken along the line BB of FIG. 6A, illustrating a manufacturing process of the infrared sensor according to the modified example (Part 2).

FIG. 7A shows a first embodiment of the first embodiment of the present invention.
FIG. 7B is a cross-sectional view taken along the line BB of FIG. 7A, showing a manufacturing process of the infrared sensor according to the modified example (part 3).

FIG. 8A shows a first embodiment of the first embodiment of the present invention.
FIG. 8B is a plan view showing a manufacturing process of the infrared sensor according to the modification of FIG. 8B, and FIG. 8B is a cross-sectional view taken along the line BB of FIG.

FIG. 9A shows a second embodiment of the first embodiment of the present invention.
FIG. 9B is a cross-sectional view taken along the line CC of FIG. 9A, showing a manufacturing process of the infrared sensor according to the modified example (Part 1).

FIG. 10A is a plan view showing a manufacturing process of an infrared sensor according to a second modification of the first embodiment of the present invention, and FIG. 10B is a plan view of FIG. FIG. 7 is a sectional configuration view taken along the line CC of FIG.

FIG. 11A is a plan view showing a manufacturing process of an infrared sensor according to a second modified example of the first embodiment of the present invention, and FIG. 11B is a plan view of FIG. 11A. FIG. 6 is a sectional configuration view taken along the line CC of FIG.

12A is a plan view of an infrared sensor according to a second embodiment of the present invention, and FIG. 12B is a cross-sectional view taken along a line DD in FIG. 12A. It is.

FIG. 13A is a plan view showing a manufacturing process of an infrared sensor according to a second embodiment of the present invention, and FIG. 13B is a view along a line DD in FIG. 13A. FIG. 2 is a cross-sectional configuration diagram (part 1).

FIG. 14A is a plan view showing a manufacturing process of an infrared sensor according to a second embodiment of the present invention, and FIG. 14B is a sectional view taken along a line DD in FIG. FIG. 2 is a sectional configuration view (part 2).

FIG. 15A is a plan view showing a manufacturing process of an infrared sensor according to a second embodiment of the present invention, and FIG. 15B is a view along a line DD in FIG. 15A. FIG. 3 is a cross-sectional configuration view (part 3).

FIG. 16A is a plan view showing a manufacturing process of an infrared sensor according to a second embodiment of the present invention, and FIG. 16B is a view along a line DD in FIG. 16A. FIG. 4 is a sectional configuration view (part 4).

FIG. 17A is a plan view of a flow rate sensor according to a third embodiment of the present invention, and FIG.
FIG. 7 (a) is a cross-sectional configuration diagram along EE.

FIG. 18 (a) is a plan view showing a manufacturing process of a flow sensor according to a third embodiment of the present invention.
FIG. 8B is a cross-sectional configuration diagram along EE in FIG. 18A (part 1).

FIG. 19 (a) is a plan view showing a manufacturing process of a flow sensor according to a third embodiment of the present invention.
FIG. 9B is a cross-sectional configuration diagram along EE in FIG. 19A (part 2).

FIG. 20A is a plan view showing a manufacturing process of a flow sensor according to a third embodiment of the present invention, and FIG.
0 (b) is a cross-sectional configuration diagram along EE in FIG. 20 (a) (part 3).

FIG. 21 is a circuit diagram showing an arrayed infrared sensor and a switch circuit according to another embodiment of the present invention.

FIG. 22A is a plan view of an infrared sensor according to the related art, and FIG.
It is sectional drawing along F.

FIG. 23A is a plan view showing a manufacturing process of an infrared sensor according to the related art, and FIG. 23B is a plan view of FIG.
FIG. 3A is a cross-sectional configuration view along line FF of FIG.

FIG. 24A is a plan view showing a manufacturing process of an infrared sensor according to the related art, and FIG.
FIG. 4A is a cross-sectional view taken along line FF of FIG.

[Explanation of symbols]

7, 130 Substrate 9, 10 Light receiving portion 13 Connection portion 22 to 24 Cavity region 28, 30 Light receiving portion 35 to 38 Connection portion 41, 42, 101, 102, 141, 142 Anisotropic etching hole 43, 93, 110 Thin film support Parts 45, 98, 111 Separation grooves 47, 132 P-type polysilicon resistance wiring 48, 133 N-type polysilicon resistance wiring 49, 134 Aluminum wiring 51, 148 Hot contact 52, 149 Cold contact 53, 143 Support insulating film 54, 144 Interlayer insulating film 55, 145 Protective film 56-58 Infrared absorbing film 60 Bolometer material film 61, 62, 146, 147 Infrared absorbing film 63, 64 Terminal 65, 150 Crystal plane 72, 75 Polycrystalline silicon film 73 Backside etching prevention film 90 Anisotropic etching holes 91, 92 Titanium wiring 94, 95 Heating elements 96, 97 Antibody part 98,99 Resistance temperature measuring wire 100 Heating element wiring 112 First infrared sensor 113 Second infrared sensor 114 Third infrared sensor 115 Fourth infrared sensor 116,118,120,122 X gate transistor 117,119 , 121 and 123 Y gate transistor 124 second output 125 the first output 126 X ₁ coordinate input 127 X ₂ coordinate input 128 Y ₁ coordinate input 129 Y ₂ coordinate input

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 49/00 H01L 21/302 J F term (Reference) 2G065 AB02 BA11 BA12 BA13 BA14 BA34 BE08 CA27 4M112 AA03 BA01 CA02 DA03 DA04 EA07 5F004 DA01 DB01 DB02 DB03 DB07 DB09 DB14 DB25 DB26 DB28 EA10 EB01 EB02 EB03 EB04 FA02

Claims (5)

[Claims] 1. A method for manufacturing a sensor, comprising at least the following steps: (A) forming a supporting insulating film on the semiconductor substrate; (b) forming a protective film on the supporting insulating film; and (c) removing a part of the protective film to form the supporting insulating film. A step of exposing a part and forming a thin film support part (d) a step of removing a part of the semiconductor substrate below the support insulating film and exposing a part of the lower part of the support insulating film (e) The thin film support is removed by dry etching,
Step of forming separation groove 2. The method according to claim 1, further comprising: a step of forming a temperature detecting element on the supporting insulating film; and a step of forming an interlayer insulating film before the step of forming the protective film. The method according to claim 1, further comprising: forming an infrared absorbing film on the protective film. 3. The method of manufacturing a sensor according to claim 1, further comprising, before the step of forming the protective film, a step of forming a physical quantity measurement unit on the supporting insulating film. 4. The semiconductor device according to claim 1, wherein the supporting insulating film is a silicon nitride film, and the protective film is a silicon oxide film.
4. The method for manufacturing a sensor according to any one of claims 3 to 3. 5. An anisotropic etching hole for etching the semiconductor substrate in a part of the supporting insulating film,
5. The method according to claim 1, wherein the protective film is formed.
A method for manufacturing a sensor according to any one of the above.