JPH10332480A - Solid state infrared image sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high sensitivity solid state infrared image sensor by arranging a plurality of wires in at least a single supporting leg. SOLUTION: A plurality of metal wires 31, 32 for supplying a current to a bolometer thin film 11 are arranged in one supporting leg 20. Insulation films 100, 110, 130 are composed of a silicon oxide, a silicon nitride, or the like, forming the mechanical structure of a detector part 10 and the insulation film 130 also serves as an interlayer insulation film between the wires 31, 32. A metal reflection film 70 is provided on an insulation film 80 below the bolometer film 11 and forms an optical resonance structure in conjunction with the detector part 10 in order to increase absorption of infrared rays at the detector part 10. Since two or more wires are arranged in one supporting leg 20, the number of the supporting legs can be decreased and the sensitivity can be enhanced because heat dissipation from the detector part 10 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a two-dimensional infrared solid-state imaging device using a thermal infrared detector.

[0002]

2. Description of the Related Art FIG. 12 is a perspective view showing an example of the structure of a conventional pixel of a two-dimensional solid-state imaging device using a bolometer, which is a thermal infrared detector whose resistance value changes with temperature. For example, an infrared detector unit 10 including a bolometer thin film 11 is provided on a substrate 1 made of a semiconductor such as silicon with a space therebetween. The two support legs 21 and 22 lift and lift the infrared detector unit 10 from the silicon substrate. The metal wirings 31 and 32 allow current to flow through the bolometer thin film 11, and ON and OFF of the current are controlled by a detection circuit.

Next, the operation of the two-dimensional infrared solid-state imaging device using the thermal infrared detector will be described. Infrared rays enter from the side where the photodetector unit 10 is present, and the photodetector unit 1
Absorbed at 0. The infrared energy absorbed by the photodetector section 10 is converted into heat, and the temperature of the photodetector section 10 is increased. The temperature rise depends on the amount of incident infrared light (the amount of incident infrared light depends on the temperature and emissivity of the imaging target). Since the amount of temperature rise can be known by measuring the change in the resistance value of the bolometer thin film, the amount of infrared radiation emitted by the imaging object can be known from the change in the resistance value of the bolometer.

[0004]

If the temperature coefficient of resistance of the bolometer thin film is the same, the greater the temperature rise of the photodetector, the greater the resistance change obtained by the same amount of incident infrared light and the higher the sensitivity. In order to increase the temperature rise, it is effective to reduce the heat escaping from the photodetector section 10 to the silicon substrate 1 as much as possible. For this reason, the supporting legs 21 and 22 are designed so as to minimize the thermal resistance. Is done. It is also important to reduce the heat capacity of the photodetector unit 10 so that the temperature time constant of the photodetector unit 10 is shorter than the frame time of the image sensor. It is also effective to increase the area of the photodetector section 10 which receives infrared rays to increase the sensitivity. However, in the conventional structure,
The heat from one photodetector unit 10 is applied to two support legs 21, 2.
2, the temperature of the photodetector did not rise sufficiently, which hindered high sensitivity.

Further, the large number of supporting legs hinders the enhancement of sensitivity. FIG. 13 is a plan view of the structure shown in FIG.
Referring to this figure, a photodetector unit 1 for receiving infrared rays
Consider the area occupied by 0 and the pixels of the support legs 21 and 22.
The width of the support leg is determined by the width of the wirings 31 and 32, the margin between the wiring and the pattern of the insulating film forming the support leg (twice the margin on one side), and the width of the detector unit 10 throughout the manufacturing process. Is determined in consideration of two widths (in this case, the thickness is also determined) determined by the mechanical strength enough to support the hollow. Heat will escape to the substrate through the two support legs determined by this width. Note that, in FIG.
2 is connected to the readout circuit via contacts 121 and 122. On each side of the support leg, a detector unit or another support leg is arranged via a gap required for pattern formation,
If the required gaps are all the same, it is necessary to allocate three gaps per pixel. Therefore, the width of the detector unit 10 in the vertical direction in the figure is a value obtained by subtracting the width of two support legs and the width of three gaps from the pixel vertical pitch, which is subject to design restrictions. The width of the photodetector 10 allocated in the drawing vertical direction is the width of two support legs 21 and 22, the width of the support legs, and the width of three gaps required between the detector unit, the support legs, and the support legs. Is subtracted from the pixel pitch.
The area of 0 is restricted, which hinders high sensitivity. An object of the present invention is to provide a high-sensitivity infrared solid-state imaging device.

[0006]

According to a first aspect of the present invention, there is provided:
The two-dimensional infrared solid-state imaging device includes a thermal photodetector section supported on a semiconductor substrate by a support leg having a large thermal resistance, and detects a change in characteristics of the thermal detector due to the incidence of infrared rays through wiring in the support leg. An infrared solid-state imaging device, wherein a plurality of wirings are arranged in at least one support leg. Preferably, in this infrared solid-state imaging device,
A plurality of wirings are stacked and arranged in at least one support leg. Preferably, in this infrared solid-state imaging device, a plurality of wirings are arranged in parallel in at least one support leg. Preferably, in the above-mentioned infrared solid-state imaging device, the lower one of the stacked wirings is arranged so as to occupy most of the area under the thermal detector. Preferably, in the infrared solid-state imaging device described above,
Two stacked wirings are arranged so as to sandwich the thermal detector.

A second infrared solid-state imaging device according to the present invention includes a thermal-type photodetector section supported by supporting legs having a large thermal resistance above a hollow section provided in a semiconductor substrate. An infrared solid-state imaging device for detecting a change in characteristics of a thermal detector unit through wiring in a support leg, wherein a plurality of wirings are arranged in at least one support leg. Preferably,
In this infrared solid-state imaging device, a plurality of wirings are stacked and arranged in at least one support leg. Preferably, in this infrared solid-state imaging device, a plurality of wirings are arranged in parallel in at least one support leg. Preferably, in the above-mentioned infrared solid-state imaging device, the lower one of the stacked wirings is arranged so as to occupy most of the area under the thermal detector. Preferably, in the above-described infrared solid-state imaging device, the two stacked wirings are arranged so as to sandwich the thermal detector.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Embodiment 1 FIG. FIG. 1 shows Embodiment 2 using a bolometer which is a thermal infrared detector and whose resistance value changes with temperature.
FIG. 2 is a schematic perspective view showing a structure of one pixel of the three-dimensional infrared solid-state imaging device, and FIG. 2 is a schematic cross-sectional view along a current path of the infrared solid-state imaging device. FIG. 2 omits a signal readout circuit provided on the substrate 1 which is not directly related to the present invention for simplicity. In the two-dimensional solid-state imaging device, the pixels shown in FIGS. 1 and 2 are two-dimensionally arranged.

In the structure shown in FIGS. 1 and 2, the infrared detector section 10 includes a bolometer thin film 11 whose resistance changes with temperature. The infrared detector section 10 is provided with a space 90 separated from the substrate 1 made of a semiconductor such as silicon. An insulating film 80 is provided on the substrate 1, and one support leg 20 having a large thermal resistance is fixed on the insulating film 80.
The infrared detector 10 is lifted off the silicon substrate 1. That is, the infrared detector section 10 is supported above the substrate 1 by one support leg 20. Infrared detector unit 1
0 denotes an insulating film 110, a metal wiring 31, and an insulating film 13 from below.
0, a bolometer film 11, a metal wiring 32 connected to the bolometer film 11, and an insulating film 100 are sequentially laminated to form a five-layer structure. The metal wirings 31 and 32 are square bolometer films 11.
Are electrically connected to both ends. The support leg 20 also has a similar five-layer structure, and a plurality of (two in this embodiment) for supplying a current to the bolometer thin film 11 is provided inside one support leg 20.
Metal wirings 31, 32 are arranged. Insulating film 10
0, 110, and 130 correspond to the support leg 20 and the detector unit 10.
The insulating film 130 is formed of a silicon oxide film, a silicon nitride film, or the like forming the mechanical structure of FIG.
It also serves as the second interlayer insulating film. On the substrate 1, a two-dimensional matrix is formed by the signal lines 50 and the read circuit control clock bus lines 60, and the read circuit 40 is provided at each intersection of the signal lines 50 and the read circuit control clock bus lines 60. The support leg 20 is attached to the substrate 1 on the signal line 50 in this embodiment. At the portion where the support leg 20 is connected to the substrate, metal wirings 31, 32
Are connected to a signal readout circuit 40 on the silicon substrate 1 (not shown) through contact holes 121 and 122 provided in the insulating films 130, 110 and 80. In the signal readout circuit 40, the metal wiring 31 is connected to a control clock line via a switch transistor, and the metal wiring 32 is connected to a signal line. switch·
The transistor turns on and off a current flowing through the wirings 31 and 32 and the bolometer thin film 11 according to a clock signal from a control clock line. Further, the metal reflection film 70 is provided on the insulating film 80 at a position corresponding to the position below the bolometer film 11, and forms an optical resonance structure with the detector unit 10 to increase the absorption of infrared rays by the detector unit 10. Let it. In some cases, the detector unit 10 is formed with a thin metal infrared absorbing film to help absorb infrared light. As is apparent from FIGS. 1 and 2, the two-dimensional infrared solid-state imaging device has a structure in which two or more wirings are arranged in one support leg 20, so that the number of support legs can be reduced as compared with the related art. Thus, the amount of heat escaping from the detector section 10 is reduced, and the sensitivity can be increased.

FIG. 3 is a plan view of the device structure shown in FIGS. 1 and 2 excluding portions related to the metal wiring 31. FIG. 4 is a plan view of the device structure shown in FIGS.
It is the top view which omitted the part regarding. Upper wiring 32
Is in contact with the left end of the bolometer film 11 as shown in FIG. 3, and the lower wiring 31 is in contact with the bolometer film 11 at the right end as shown in FIG. As is clear from FIGS. 3 and 4, this two-dimensional infrared solid-state imaging device can reduce the number of supporting legs compared to the conventional one, so that the area allocated to the detector unit 10 is smaller than that of the conventional one. Can be increased by the reduced amount. The area equivalent to the sum of the area occupied by the support legs in the reduced portion and the area corresponding to the gap between the support legs and the detector unit can also be assigned to the photodetector unit, increasing the aperture ratio. This is effective for increasing the sensitivity.

Next, the operation of detecting infrared light of the pixels of the two-dimensional infrared solid-state imaging device using the thermal infrared detector according to the present embodiment will be described. Infrared rays enter from the detector section 10 side. The incident infrared rays are absorbed by the detector unit 10 and increase the temperature of the detector unit 10. The temperature rise of the detector unit 10 is detected by a change in resistance of the bolometer film 11.
This resistance change is applied to the wirings 31, 32, contacts 121, 1
An infrared ray is detected by detecting the signal through a signal readout circuit 22 formed on a silicon substrate. The reflection film 70
And the detector section 10 form an optical resonance structure to enhance the efficiency of infrared absorption.

Embodiment 2 FIG. 5 and 6 are schematic sectional views along a current path of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to a second embodiment of the present invention, and correspond to FIG. 3 of the first embodiment. It is a top view. In this structure, as shown in FIG. 6, the lower metal wiring 32 is formed below the bolometer film 11 so as to extend from the bolometer film 11, and the reflection film formed by the element of the first embodiment is removed. I have. Other components are the same as those of the first embodiment.

In this structure, the metal electrode 32 functions as a reflection film in a portion of the metal wiring 32 located on the bolometer film 11. Insulating films 130 and 10 on metal electrode 32
The optical resonance structure is configured by appropriately designing the film type and the film thickness of the bolometer film 11 (and the thin metal infrared absorption film formed on any part of the metal wiring in some cases). can do. In the first embodiment, the degree of the effect of the optical resonance structure changes according to the height of the cavity 90, and depending on the configuration of the film, the detector unit 11 and the support legs 20 may be warped, so that control is difficult. In the structure of the present embodiment, the effect of the optical resonance structure is determined by the thickness of the solid thin film, and is easy to control and stable.

Embodiment 3 FIG. 7 is a cross-sectional structure along a current path of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to a third embodiment of the present invention. In this embodiment, the bolometer film 11 of the first embodiment shown in FIGS. 1 and 2 is sandwiched between electrodes 31 and 32. That is, in the portion where the bolometer film 11 exists,
The infrared detector unit 10 includes an insulating film 110, a metal electrode 31, a bolometer film 11, a metal electrode 32, and an insulating film 100 from below.
Are stacked, and the two electrodes 31 and 32 are arranged so as to be in contact with almost the entire bolometer film 11 in plan view.

If the upper electrode 32 can be made of a material that transmits infrared rays or can be made thinner enough to transmit infrared rays, the lower electrode 31 can be operated as a reflection film.
In this case, although not shown, if a thin-film metal infrared absorbing layer is provided on an arbitrary portion located above the wiring 31, infrared rays can be absorbed more efficiently. In the case where the electrode 32 cannot be made thin enough to transmit infrared rays or sufficiently transmit infrared rays, the electrode 32 on the upper side (light incident side) can be operated as a reflection film. In this case, although not shown, infrared light can be absorbed more efficiently by providing a thin-film metal infrared absorbing layer on an arbitrary portion located above the wiring 32.

In the first to third embodiments, the detector is a bolometer and the wiring is two elements. However, even in the case where another detector that requires three or more wirings is used, in the first to third embodiments, by disposing the part or all of them on one support leg, The number of supporting legs can be reduced as compared with the structure, and the same effect can be obtained. Further, in the above-described first to third embodiments, the stacked wirings are shown. However, although the thermal effect is slightly reduced, a similar effect can be obtained even if the wires are arranged in parallel in one support leg in the first to third embodiments.

Embodiment 4 FIG. 8 is a schematic perspective view showing the structure of one pixel of a two-dimensional solid-state imaging device using a bolometer whose resistance value changes with temperature, which is a thermal infrared detector according to Embodiment 4 of the present invention. FIG. 9 is a schematic sectional view along a current path of the two-dimensional infrared solid-state imaging device. 8 and 9, a signal readout circuit provided on the substrate 1 which is not directly related to the present invention is omitted for simplicity. In the two-dimensional solid-state imaging device, the pixels shown in FIGS. 8 and 9 are two-dimensionally arranged. In the structure shown in FIGS. 8 and 9, the infrared detector unit 10 has the same structure as that of the above-described embodiment, and is similarly provided with a space separated from the substrate 1 made of a semiconductor such as silicon. Are different. A concave portion (hollow portion) 200 is formed on the upper portion of the silicon substrate 1, and the infrared detector
0 is located above. There is room in the plane layout of the circuit,
This simple structure is suitable when it is not necessary to stack the readout circuit for each pixel with the detector section.

One support leg 20 having a large thermal resistance raises the infrared detector unit 10 by lifting it from the silicon substrate 1 and supports it above the substrate 1. However, unlike the above-described embodiment, the infrared detector section 10 and the support leg 20 are formed in the same plane, that is, at the same height with respect to the substrate 1. The infrared detector section 10 and the support leg 20 are formed from below with the insulating film 110, the metal wiring 31, the insulating film 130, and the bolometer film 1.
1 and metal wiring 32 connected thereto, insulating film 100
Are sequentially laminated. Metal wiring 31, 3
2 is electrically connected to both ends of the square bolometer film 11. A plurality of (two in this embodiment) metal wirings 31 and 32 for flowing a current to the bolometer thin film 11 are arranged in one support leg 20. In the present embodiment, the support leg 20 is attached to the substrate 1 at the intersection of the signal line 50 and the read circuit control clock bus line 60. Support leg 2
0 is a portion connected to the substrate, and the metal wirings 31 and 32 are
Through a contact hole 121, 122 provided in the insulating film 130, 110, 80, it is connected to a signal reading circuit (not shown) on the silicon substrate 1. In this signal reading circuit, the metal wiring 31 is connected to a control clock line via a switch transistor,
2 is connected to the signal line. The switch transistor turns on and off the current flowing through the wirings 31 and 32 and the bolometer thin film 11 according to a clock signal from the control clock line.

Embodiment 5 FIG. 10 shows a sectional structure along a current path of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to another embodiment 5 of the present invention. The structure of the infrared detector unit 10 and a plurality of metal wirings 3 for passing a current through the bolometer thin film 11 in one support leg 20
1 and 32 are the same as in the second embodiment, except that a concave portion 200 is formed in the silicon substrate 1.
The point that the support leg 20 is formed at the same height as the infrared detector unit 10 is the same as in the fourth embodiment. If there is room in the planar arrangement of the circuit and it is not necessary to stack the readout circuit for each pixel with the detector section, this simple structure is suitable.

Embodiment 6 FIG. 11 shows a sectional structure along a current path of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to another embodiment of the present invention.
The structure of the infrared detector unit 10 and the point in which a plurality of metal wirings 31 and 32 for flowing a current to the bolometer thin film 11 in one support leg 20 are the same as those in the third embodiment. However, it is the same as the fourth embodiment in that the concave portion 200 is formed in the silicon substrate 1 and the support leg 20 is formed at the same height as the infrared detector unit 10. If there is room in the planar arrangement of the circuit and it is not necessary to stack the readout circuit for each pixel with the detector section, this simple structure is suitable. In the above fourth to sixth embodiments, the detector has a bolometer and two wires. However, even in the case of another detector that requires three or more wires, in Embodiments 4 to 6, by laminating all or all of the parts, the number of supporting legs can be reduced as compared with the conventional structure. The same effect is achieved. In the fourth to sixth embodiments, the stacked wirings are shown. However, although the thermal effect is slightly reduced, a similar effect can be obtained even if the wires are arranged in parallel in one support leg in the fourth to sixth embodiments.

[0021]

The infrared solid-state imaging device according to the present invention includes a thermal photodetector section supported on a semiconductor substrate by a supporting leg having a large thermal resistance, and detects a change in characteristics of the thermal detector due to the incidence of infrared rays. An infrared solid-state imaging device for detecting through a wiring in a supporting leg. Since a plurality of wirings are arranged in at least one supporting leg, the number of supporting legs can be reduced, and the amount of heat escaping through the supporting leg can be reduced. And high sensitivity can be realized. In addition, since the number of supporting legs can be reduced, the area allocated to the supporting legs can be reduced, and as a result, the area of the detector section can be increased and the aperture ratio can be increased, thereby achieving high sensitivity. . Preferably, in this infrared solid-state imaging device, since a plurality of wirings are stacked and arranged in at least one support leg, the number of support legs can be reduced. Preferably, in this infrared solid-state imaging device, a plurality of wirings are arranged in parallel in at least one support leg, so that the number of support legs can be reduced.
Preferably, in this infrared solid-state imaging device, the lower wiring among the stacked wirings is arranged so as to occupy most of the area under the thermal detector, so that the lower wiring is used as a reflection film. Can be used to form a stable optical resonance structure. Preferably, in this infrared solid-state imaging device, 2
Since the two stacked wirings are arranged so as to sandwich the thermal detector, the upper or lower wiring can be used as a reflection film. An infrared solid-state imaging device according to the present invention includes a thermal-type photodetector section supported by a supporting leg having a large thermal resistance above a cavity provided in a semiconductor substrate, and a characteristic of the thermal-type detector due to incidence of infrared rays. An infrared solid-state imaging device that detects a change through a wiring in a supporting leg, and a plurality of wirings are arranged in at least one supporting leg, so that the number of supporting legs can be reduced, and the amount of heat escaping through the supporting leg can be reduced. The sensitivity can be reduced and the sensitivity can be increased. In addition, since the number of supporting legs can be reduced, the area allocated to the supporting legs can be reduced, and as a result, the area of the detector section can be increased and the aperture ratio can be increased, thereby achieving high sensitivity. . Preferably, in this infrared solid-state imaging device, a plurality of wirings are stacked and arranged in at least one support leg.
The number of supporting legs can be reduced. Preferably, in this infrared solid-state imaging device, a plurality of wirings are arranged in parallel in at least one support leg, so that the number of support legs can be reduced. Preferably, in this infrared solid-state imaging device, the lower wiring among the stacked wirings is arranged so as to occupy most of the area under the thermal detector, so that the lower wiring is used as a reflection film. Can be used to form a stable optical resonance structure. Preferably, in this infrared solid-state imaging device, the two stacked wirings are arranged so as to sandwich the thermal detector, so that the upper or lower wiring can be used as a reflection film.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to Embodiment 1 of the present invention.

FIG. 2 shows a schematic diagram of a second example using the thermal infrared detector according to the first embodiment.
FIG. 2 is a schematic cross-sectional view along a current path of a pixel of the three-dimensional infrared solid-state imaging device.

FIG. 3 shows a second example using the thermal infrared detector according to the first embodiment.
The top view which shows the layout of the upper wiring of the pixel of the three-dimensional infrared solid-state imaging device.

FIG. 4 shows a second example using the thermal infrared detector according to the first embodiment.
FIG. 3 is a plan view showing a layout of a lower wiring of a pixel of the three-dimensional infrared solid-state imaging device.

FIG. 5 is a schematic cross-sectional view along a current path of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to Embodiment 2 of the present invention.

FIG. 6 shows a second example using the thermal infrared detector according to the second embodiment.
FIG. 3 is a plan view showing a layout of a lower wiring of a pixel of the three-dimensional infrared solid-state imaging device.

FIG. 7 is a schematic cross-sectional view along a current path of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to Embodiment 3 of the present invention.

FIG. 8 is a schematic perspective view of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to Embodiment 4 of the present invention.

FIG. 9 is a schematic cross-sectional view along a current path of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to Embodiment 4 of the present invention.

FIG. 10 is a schematic cross-sectional view along a current path of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to Embodiment 5 of the present invention.

FIG. 11 is a schematic sectional view along a current path of a pixel of a two-dimensional infrared solid-state imaging device using a thermal infrared detector according to Embodiment 6 of the present invention.

FIG. 12 is a perspective view showing the structure of a pixel of a two-dimensional infrared solid-state imaging device using a conventional thermal infrared detector.

FIG. 13 is a plan view showing a pixel structure of a two-dimensional infrared solid-state imaging device using a conventional thermal infrared detector.

[Explanation of symbols]

1 silicon substrate, 10 infrared detector section, 1
1 bolometer thin film, 21, 22 support leg, 31,
32 metal wiring, 40 readout circuit, 50 signal line, 60 readout circuit control clock bus line, 70 reflective film, 80 insulating film, 9
0 cavity, 100 insulating film, 110 insulating film, 121, 122 contact, 130 insulating film, 200 cavity in substrate.

Claims (10)

[Claims] 1. An infrared sensor comprising a thermal photodetector section supported on a semiconductor substrate by supporting legs having a large thermal resistance, and detecting a characteristic change of the thermal detector section due to the incidence of infrared rays through a wiring in the supporting leg. An infrared solid-state image sensor, wherein a plurality of wirings are arranged in at least one support leg. 2. The infrared solid-state imaging device according to claim 1, wherein a plurality of wirings are stacked and arranged in at least one support leg. 3. The infrared solid-state imaging device according to claim 1, wherein a plurality of wirings are arranged in parallel in at least one support leg. 4. The infrared solid-state imaging device according to claim 1, wherein the lower one of the stacked wirings occupies most of the area under the thermal detector. An infrared solid-state imaging device, wherein: 5. The infrared solid-state imaging device according to claim 1, wherein two stacked wirings are arranged so as to sandwich the thermal detector. . 6. A thermal-type photodetector section supported by supporting legs having a large thermal resistance over a cavity provided in a semiconductor substrate,
An infrared solid-state imaging device that detects a change in characteristics of the thermal detector unit due to the incidence of infrared rays through wiring in the support legs,
An infrared solid-state imaging device, wherein a plurality of wirings are arranged in at least one support leg. 7. The infrared solid-state imaging device according to claim 6, wherein a plurality of wirings are stacked and arranged in at least one support leg. 8. The infrared solid-state imaging device according to claim 6, wherein a plurality of wirings are arranged in parallel in at least one support leg. 9. The infrared solid-state imaging device according to claim 6, wherein the lowermost one of the stacked wirings occupies most of the area under the thermal detector. An infrared solid-state imaging device, wherein: 10. The infrared solid-state imaging device according to claim 6, wherein two stacked wirings are arranged so as to sandwich the thermal detector. .