JP2000065639A - Infrared sensor - Google Patents

Abstract

(57) [Summary] [Problem] Without increasing the size of a silicon substrate,
A thermal infrared sensor with high temperature resolution is obtained by increasing the number of thermocouples to increase the output. SOLUTION: A central heat sink 26 (cold junction formation region) is provided at the center of a silicon substrate 22, and an outer peripheral side heat sink 27 (cold junction formation region) is provided on the outer periphery of the silicon substrate 22 with a cavity 24 interposed therebetween. A heat insulating thin film 25 is placed on the cavity 24.
(Hot junction forming area) is provided. The thermopile 30 is wired in a zigzag manner between the central heat sink 26 and the outer heat sink 27 via the heat insulating thin film 25, and the hot junction 32 of the thermopile 30 is arranged on the heat insulating thin film 25 and the infrared ray absorber 34 is used. Cover and connect the cold junction 31 to each heat sink 2
6 and 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an infrared sensor for measuring an infrared ray amount, a temperature, or a temperature change with a plurality of thermocouples connected in series.

[0002]

2. Description of the Related Art In recent years, thermal infrared sensors for detecting infrared rays emitted from the human body and the like have been used in various fields such as security devices and thermometers. A thermal infrared sensor is a sensor that uses infrared rays as heat rays and outputs physical quantities (electromotive force, electric charge, resistance change, etc.) according to temperature changes caused by the incidence of infrared rays. Thermopile that outputs thermoelectromotive force Type, a pyro type that outputs electric charge by the pyroelectric effect, and a thermistor bolometer type that uses the temperature change of electric resistance.

FIGS. 1A and 1B show a conventional structure of a thermopile type temperature sensor among the above-mentioned thermal type infrared sensors.
FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view. In this thermopile type temperature sensor 1, a heat insulating thin film 4 is provided on the upper surface of a hollow portion 3 in a frame-shaped heat sink 2 made of a silicon substrate. A large number of two kinds of metals or semiconductors (first thermoelectric member 5 and second thermoelectric member 6) are arranged from the heat sink 2 to the heat insulating thin film 4, and both metals are joined on the heat sink 2 to form a cold junction of a thermocouple. 7 is formed, and both metals are joined on the upper surface of the heat insulating thin film 4 to form a hot junction 8 of a thermocouple.
Are formed, and electrodes 10 are provided at both ends of a thermopile 9 in which thermocouples are connected in series. Thermal insulating thin film 4
The hot junction 8 formed on the top is covered with an infrared absorber 11 formed in a rectangular shape.

[0004] The thermopile-type temperature sensor 1 detects that infrared rays are absorbed by the infrared absorber 11 and converted into heat.
When a temperature difference occurs between the cold junction 7 and the hot junction 8, an electromotive force is generated between the electrodes 10 of the thermopile 9. That is, when the temperature of the junction (thermocouple) of the first and second thermoelectric members 5 and 6 is T,
Assuming that the thermoelectromotive force generated at the junction is represented by φ (T), m hot junctions 8 are provided on the heat insulating thin film 4,
Assuming that m cold junctions 7 are also provided on the heat sink 2, the temperature of the hot junction 8 is Tw and the temperature of the cold junction 7 is T
When it is c, an electromotive force V represented by the following equation (1) is generated between the electrodes 10 at both ends of the thermopile 9. V = m [φ (Tw) −φ (Tc)] (1)

Therefore, if the temperature Tc of the heat sink 2 is known, the temperature Tw of the object to be measured can be measured in a non-contact manner by measuring the electromotive force V generated between the electrodes 10.

[0006]

As can be seen from the above equation (1), since the thermoelectromotive force output from the thermopile type temperature sensor is the sum of the thermoelectromotive forces of the thermocouples, the thermoelectric devices connected in series are connected. The larger the number of pairs, the larger the thermoelectromotive force and the higher the temperature resolution.

However, in the conventional thermopile type temperature sensor, a cold junction is formed on a heat sink left around the silicon substrate, and a heat insulating thin film is formed on a cavity formed in the center of the silicon substrate. Is formed to form a hot junction on the heat insulating thin film. Therefore, for a chip size (silicon substrate size) of several mm square, the number of thermocouples that can be formed due to restrictions on pattern design is 40 to 50 was the limit.

[0008] A large number of thermocouples can be formed by increasing the chip size. However, depending on the application (for example, an ear thermometer that measures the body temperature by being inserted into the ear canal), the chip size is increased. Therefore, a reduction in chip size is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to form a large number of thermocouples in a small chip size to increase the output of an infrared sensor and to increase the temperature. The purpose is to increase the resolution.

[0010]

In the infrared sensor according to the first aspect, a thermopile is wired on a hot junction forming area and a cold junction forming area of a substrate, and a thermopile hot junction is arranged on the hot junction forming area. In an infrared sensor in which a thermopile cold junction is arranged on a cold junction formation area, a plurality of cold junction formation areas separated by a hot junction formation area are provided.

The infrared sensor according to claim 2 is
Infrared with a thermopile wired on the hot junction formation area and the cold junction formation area of the substrate, a thermopile hot junction arranged on the hot junction formation area, and a thermopile cold junction arranged on the cold junction formation area The sensor is characterized in that a plurality of hot junction forming regions separated by a cold junction forming region are provided.

In the infrared sensor according to the first or second aspect, since a larger number of hot junction forming regions or cold junction forming regions can be provided than in the conventional example, a larger number of hot junctions and cold junctions can be provided thereon. Can be formed. Therefore, a large number of thermocouples can be provided on a substrate having a small chip size, the output of the infrared sensor can be increased without increasing the chip size, and the temperature resolution of the infrared sensor can be increased.

Further, by providing a large number of hot junction forming regions or cold junction forming regions, the area of the hot junction forming region is reduced if the chip size is the same. In addition, the mechanical strength of the hot junction forming region can be increased. Also, when the thin-film hot junction forming region is formed by etching, the etching area can be reduced, so that the etching time can be shortened.

According to a third aspect of the present invention, there is provided an infrared sensor, wherein a thermopile is wired on a hot junction forming area and a cold junction forming area of a substrate, and a thermopile hot junction is arranged on the hot junction forming area. In the infrared sensor in which a thermopile cold junction is arranged on a formation area, the cold junction formation area is formed by bending or intersecting, and the thermopile is wired along substantially the entire outer edge of the cold junction formation area. And

Further, the infrared sensor according to claim 4 is
Infrared with a thermopile wired on the hot junction formation area and the cold junction formation area of the substrate, a thermopile hot junction arranged on the hot junction formation area, and a thermopile cold junction arranged on the cold junction formation area The sensor is characterized in that the hot junction forming region is formed by bending or crossing, and a thermopile is wired along substantially the entire outer edge of the hot junction forming region.

In the infrared sensor according to the third or fourth aspect, since the hot junction forming area and the cold junction forming area are bent or crossed, the outer edges of the hot junction forming area and the cold junction forming area are formed. Since the distance is long and the thermopile is formed along substantially the entire extension, a large number of hot junctions and cold junctions can be formed. Therefore, even in these infrared sensors, a large number of thermocouples can be provided on a substrate having a small chip size, and the output of the infrared sensor can be increased without increasing the chip size. Resolution can be increased.

[0017]

(First Embodiment) FIG. 2 is a plan view showing a structure of an infrared sensor 21 according to a first embodiment of the present invention, and FIGS. 3 (a) and 3 (b) are bottom views thereof. It is sectional drawing. In this infrared sensor 21, FIG.
As shown in (b), the upper surface of the silicon substrate 22 is covered with SiO 2.
₂ and a dielectric thin film 23 of SiN or the like, the silicon substrate 2
2 is etched from the back side to form an annular cavity 24 in the silicon substrate 22. At this time, the silicon substrate 2
2 is selectively etched and the dielectric thin film 23 is not etched, so that the dielectric thin film 23 is exposed on the top surface in the cavity 24 (hereinafter, the dielectric thin film 23 is exposed in the cavity 24). The hot junction forming region is a heat insulating thin film 2
Five. ). Therefore, a central heat sink 26 (a cold junction forming region composed of the silicon substrate 22 and the dielectric thin film 23) is formed in the center of the silicon substrate 22, and an outer peripheral heat sink 27 (the silicon substrate 22 and the dielectric thin film 23) is formed in the outer peripheral portion. Is formed, and the center heat sink 26 and the outer heat sink 27 are separated by the hollow portion 24 having a tapered cross section. The heat insulating thin film 25 has a thickness of several microns in order to reduce the heat capacity.

As shown in FIG. 2, a first thermoelectric material 28 and a second thermoelectric material 29 are alternately arranged between the outer peripheral heat sink 27 and the central heat sink 26 via the heat insulating thin film 25 to form a zigzag pattern. Thermopile 30 is formed. The first thermoelectric material 28 and the second thermoelectric material 29 are joined on the outer heat sink 27 to form a cold junction 31 of a thermocouple.
Are formed on the heat insulating thin film 25 to form a hot junction 32, and further bonded on the central heat sink 26 to form a cold junction 31. In this way, the thermopile 30 for temperature measurement, in which a large number of thermocouples are connected in series, is wired in a zigzag manner along the heat insulating thin film 25, and electrodes 3 are provided at both ends of the thermopile 30, respectively.
3 are provided. Further, an infrared absorber 34 made of metal black such as Au or Bi is provided along the heat insulating thin film 25, and each hot junction 32 is covered with the infrared absorber 34.

When infrared light is incident on the infrared sensor 21, the infrared light is absorbed by an infrared absorber 34 formed on the hot junction 32 and converted into heat. Then, the cold junction 31 formed on the central heat sink 26 and the outer heat sink 27 and the hot junction 32 formed on the heat insulating thin film 25 are formed.
Is generated between the electrodes 33 of the thermopile 30 due to the temperature difference.

In the infrared sensor 1 having the structure as in the conventional example, only 0.5 hot junctions 32 and 0.5 cold junctions 31 can be provided for each linear pattern portion of the thermopile 9. 21, the heat sink (central heat sink 2) separated by the cavity 24 is provided.
6. By providing two outer heat sinks 27), one hot junction 32 and one cold junction 31 can be provided for each linear pattern portion of the thermopile 30, thereby achieving twice the thermocouple density. be able to. Therefore, a large number of thermocouples can be provided in a small chip size, the output of the infrared sensor 21 can be increased without increasing the chip size, and the temperature resolution of the infrared sensor 21 can be increased.

(Second Embodiment) FIGS. 4A and 4B are a plan view and a sectional view showing the structure of an infrared sensor 41 according to a second embodiment of the present invention. This infrared sensor 41
In this case, the silicon substrate 22 is etched from the rear surface while leaving the central portion and the outer peripheral portion of the silicon substrate 22 to expose the heat insulating thin film 25 on the top surface of the hollow portion 24 that is opened in an annular shape. That is, the shape of the silicon substrate 22 is the same as that of the first embodiment, and the central heat sink 26 and the outer heat sink 27 are separated by the cavity 24.

In this infrared sensor 41, the distance between the upper surface of the outer heat sink 27 and the heat insulating thin film 25 is
A thermopile 30 having a zigzag pattern is formed by alternately wiring the first thermoelectric materials 28 and the second thermoelectric materials 29. The first thermoelectric material 28 and the second thermoelectric material 29 of the thermopile 30 are joined on the outer heat sink 27 to form a cold junction 31, and joined on the heat insulating thin film 25 to form a hot junction 32. . In addition, a thermopile 30 having a zigzag pattern is formed between the upper surface of the central heat sink 26 and the heat insulating thin film 25 by alternately wiring the first thermoelectric material 28 and the second thermoelectric material 29. The first thermoelectric material 28 and the second thermoelectric material 29 of the thermopile 30 are joined on the central heat sink 26 to form a cold junction 31, and joined on the heat insulating thin film 25 to form a hot junction 32. Thus, the thermopile 30 arranged annularly along the outer periphery of the heat insulating thin film 25 and the thermopile 3 arranged annularly along the inner periphery of the heat insulating thin film 25.
0 is connected in series at the ends, and electrodes 33 are provided at both ends. Further, along the heat insulating thin film 25, an infrared absorber 34 made of metal black such as Au, Bi, etc.
, And each hot junction 32 is covered with an infrared absorber 34.

Even with the infrared sensor 41 having the thermopile 30 having such a pattern, the hot junction 32 and the cold junction 31 can be formed at the same density as the infrared sensor 41 of the first embodiment, and the infrared sensor 41 can output high power. Can be

(Third Embodiment) FIG. 5 is a plan view showing the structure of an infrared sensor 42 according to a third embodiment of the present invention, and FIGS. 6 (a) and 6 (b) are a bottom view and a sectional view thereof. .
In the infrared sensor 42, after the dielectric thin film 23 is formed on the upper surface of the silicon substrate 22,
The silicon substrate 22 is etched from the back surface side, leaving the inner and outer peripheral portions of the silicon substrate 22 open. Therefore, a rectangular hollow portion 24 is formed at the center of the silicon substrate 22.
a is formed, an inner heat sink 27a is formed outside thereof, and an annular cavity 24b is formed outside thereof,
An outer heat sink 27b is formed outside the outer heat sink 27b. Further, since only the silicon substrate 22 is selectively etched and the dielectric thin film 23 is not etched, the heat insulating thin film is formed in the hollow portion 24a formed in the center portion of the silicon substrate 22 and the hollow portion 24b on the outer peripheral side thereof. 25
a and 25b are exposed.

As shown in FIG. 5, the infrared sensor 42
In the above, the first thermoelectric material 28 and the second thermoelectric material 29 are alternately wired between the upper side of the outer peripheral heat sink 27b and the outer peripheral heat insulating thin film 25b to form the thermopile 30 having a zigzag pattern. The first thermoelectric material 28 and the second thermoelectric material 29 of the thermopile 30 are joined on the outer heat sink 27b to form the cold junction 31, and joined on the heat insulating thin film 25b to form the hot junction 32. The heat insulating thin film 25b and the inner heat sink 2
A thermopile 30 having a zigzag pattern is formed between the upper part 7a and the first thermoelectric material 28 and the second thermoelectric material 29 alternately. The first of this thermopile 30
The thermoelectric material 28 and the second thermoelectric material 29 are joined on the inner peripheral heat sink 27a to form a cold junction 31, and joined on the heat insulating thin film 25b to form a hot junction 32. Further, a first thermoelectric material 28 and a second thermoelectric material 28 are provided between the upper part of the inner peripheral heat sink 27a and the central heat insulating thin film 25a.
A thermopile 30 having a zigzag pattern is formed by alternately wiring thermoelectric materials 29. This thermopile 30
The first thermoelectric material 28 and the second thermoelectric material 29 are joined on the inner peripheral heat sink 27a to form the cold junction 31, and joined on the heat insulating thin film 25a to form the hot junction 32.

Thus, the thermopile 30 annularly arranged along the outer peripheral portion of the heat insulating thin film 25b, the thermopile 30 annularly arranged along the inner peripheral portion of the heat insulating thin film 25b, and the heat insulating thin film 25a Are connected in series with the thermopile 30 arranged in an annular shape along the circumference thereof, and electrodes 33 are provided at both ends thereof. Further, Au and Bi are formed along each of the heat insulating thin films 25a.
An infrared absorber 34 made of metallic black is provided, and each hot junction 32 is covered with the infrared absorber 34.

In the infrared sensor 42 having such a structure,
The density of the hot junction 32 and the cold junction 31 can be further increased, and the output of the infrared sensor 42 can be further increased.

(Fourth Embodiment) FIGS. 7A and 7B are a plan view and a sectional view showing the structure of an infrared sensor 43 according to a fourth embodiment of the present invention. This infrared sensor 43
In the above, the shape of the silicon substrate 22 having the dielectric thin film 23 formed on the upper surface is the same as that used in the third embodiment, but the pattern of the thermopile 30 is different from that of the third embodiment. Is different. That is, in the infrared sensor 43, the first thermoelectric material 28 and the second thermoelectric material are placed between the outer heat sink 27b and the central heat insulating thin film 25a, the inner heat sink 27a or the outer heat insulating thin film 25b. 29 are alternately wired to form a thermopile 30 having a zigzag pattern. Then, the first thermoelectric material 28 and the second thermoelectric material 29 are joined on the outer and inner heat sinks 27b and 27a to form the cold junction 31 of the thermocouple.
Are formed, and are joined by both the heat insulating thin films 25a and 25b to form the hot junction 32. As shown in FIGS. 7A and 7B, the cold junction 31 and the hot junction 32
The thermopile 30 is also formed at a position where the thermopile 30 passes through the heat insulating thin film 25b on the outer peripheral side and the heat sink 27a on the inner peripheral side. Electrodes 33 are provided at both ends of the thermopile 30 wired in zigzag. further,
An infrared absorber 34 made of metal black such as Au or Bi is provided on each of the heat insulating thin films 25a and 25b on the center and outer peripheral sides, and each hot junction 32 is covered with the infrared absorber 34.

Therefore, as can be seen from FIG. 7A, the infrared sensor 43 having a large cold junction and hot junction density can be manufactured.

(Fifth Embodiment) FIG. 8 is a plan view showing the structure of an infrared sensor 44 according to a fifth embodiment of the present invention, and FIGS. 9A and 9B are a bottom view and a sectional view thereof. .
In this infrared sensor 44, the dielectric thin film 2
The silicon substrate 22 on which the substrate 3 is formed is etched in a U-shape from the lower surface side to form a cavity 24, and the thermally insulating thin film 25 is exposed on the top surface of the cavity 24.

A thermopile 30 having a zigzag pattern is formed between the heat sink 45 and the heat insulating thin film 25 by alternately wiring the first thermoelectric material 28 and the second thermoelectric material 29. The first thermoelectric material 28 of the thermopile 30 and the second thermoelectric material 28
The thermoelectric material 29 is joined on the heat sink 45 to form the cold junction 31, and joined on the heat insulating thin film 25 to form the hot junction 32. Thus, the thermopile 30 arranged zigzag along the outer peripheral portion of the heat insulating thin film 25
Are provided with electrodes 33 at both ends. Further, an infrared absorber 34 made of metal black such as Au or Bi is provided along the heat insulating thin film 25, and each hot junction 32 is covered with the infrared absorber 34.

In this embodiment, since the thermopile 30 is formed along the edge of the hollow portion 24 bent in a U-shape, the distance along the line forming the thermopile 30 is long, and a large number of small chip sizes are required. The hot junction 32 and the cold junction 31 can be formed, and the output of the infrared sensor 44 can be increased.

In this embodiment, the U-shaped hollow portion 2 is used.
Since the thermopile 30 is provided on the outer periphery and the inner periphery of 4, the density of the cold junction 31 and the hot junction 32 can be increased.

The cavity 24 is not limited to the U-shape, but may be a T-shape or a cross (not shown).

(Sixth Embodiment) FIG. 10 shows a sixth embodiment of the present invention.
11 (a) and 11 (b) are a bottom view and a sectional view showing the structure of the infrared sensor 46 according to the embodiment. In the infrared sensor 46, a plurality of rectangular cavities 24 formed by etching the silicon substrate 22 having the dielectric thin film 23 formed on the upper surface from the lower surface side are arranged in a lattice pattern. The heat insulating thin film 25 is exposed on the top surface.

The first thermoelectric material 28 is provided between the heat sink 45 and the heat insulating thin film 25 around each cavity 24.
And the second thermoelectric material 29 are alternately wired to form a thermopile 30 having a zigzag pattern. The first thermoelectric material 28 and the second thermoelectric material 29 of the thermopile 30 are joined on a heat sink 45 to form a cold junction 31, and joined by a heat insulating thin film 25 to form a hot junction 32. The thermopiles 30 formed in a zigzag around the respective heat insulating thin films 25 are connected in series, and electrodes 33 are provided at both ends of the entire thermopile 30 connected in series. Furthermore, each heat insulating thin film 25
Absorber 3 made of metal black such as Au or Bi
4 and each hot junction 32 is covered with an infrared absorber 34.

In this embodiment, a large number of cavities 2
4, the large number of hot junctions 32 and cold junctions 31 can be formed in a small chip size, and the output of the infrared sensor 46 can be increased.

(Seventh Embodiment) FIG. 12 shows a seventh embodiment of the present invention.
13 (a) and 13 (b) are a bottom view and a sectional view showing the structure of the infrared sensor 47 according to the embodiment. In this infrared sensor 47, a plurality of rectangular cavities 24 formed by etching the silicon substrate 22 having the dielectric thin film 23 formed on the upper surface from the lower surface side are arranged side by side. The heat insulating thin film 25 is exposed on the surface.

The first thermoelectric material 28 is provided between the heat sink 45 and the heat insulating thin film 25 around each cavity 24.
And the second thermoelectric material 29 are alternately wired to form a thermopile 30 having a zigzag pattern. The first thermoelectric material 28 and the second thermoelectric material 29 of the thermopile 30 are joined on a heat sink 45 to form a cold junction 31, and joined by a heat insulating thin film 25 to form a hot junction 32. The thermopiles 30 formed in a zigzag around the respective heat insulating thin films 25 are connected in series, and electrodes 33 are provided at both ends of the entire thermopile 30 connected in series. Furthermore, each heat insulating thin film 25
Absorber 3 made of metal black such as Au or Bi
4 and each hot junction 32 is covered with an infrared absorber 34.

Also in this embodiment, a large number of cavities 2
4, the large number of hot junctions 32 and cold junctions 31 can be formed in a small chip size, and the output of the infrared sensor 47 can be increased.

(Eighth Embodiment) FIGS. 14A and 14B are a plan view and a sectional view showing the structure of an infrared sensor 48 according to an eighth embodiment of the present invention. This infrared sensor 4
8, the shape of the silicon substrate 22 having the dielectric thin film 23 formed on the upper surface is the same as that used in the seventh embodiment, but the pattern of the thermopile 30 is the same as that of the seventh embodiment.
Is different from the embodiment. That is, in the infrared sensor 48, the first thermoelectric material 28 and the second thermoelectric material 28 pass through the intermediate heat insulating thin film 25 and the heat sink 45 and are located between the left end heat insulating thin film 25 and the right end heat insulating thin film 25. Thermoelectric materials 29 are alternately wired to form a thermopile 30 having a zigzag pattern. Then, the first thermoelectric material 28 and the second thermoelectric material 29 are joined on the heat sink 45 to form the cold junction 31 of the thermocouple, and are joined by the heat insulating thin films 25 to form the hot junction 32. Electrodes 33 are provided at both ends of the thermopile 30 wired in zigzag. Further, an infrared absorber 34 made of metal black such as Au or Bi is provided on each of the heat insulating thin films 25 on the center and outer peripheral sides, and each hot junction 32 is covered with the infrared absorber 34.

Therefore, also in this embodiment, the large cold junction 3
One and hot junction 32 density infrared sensors 48 can be fabricated.

(Ninth Embodiment) FIGS. 15A and 15B are a plan view and a sectional view showing the structure of an infrared sensor 49 according to a ninth embodiment of the present invention. This infrared sensor 4
9 is a modification of the eighth embodiment, in which the silicon substrate 2
2, a hollow portion 24 extending in a direction inclined at an angle of 45 degrees with respect to the vertical or horizontal direction is provided, and the thermopile 30 is also wired along the direction at an angle of 45 degrees.

In FIGS. 15 to 19, the thermopile 30, the cold junction 31 and the hot junction 32 are schematically shown.

(Tenth Embodiment) FIGS. 16A and 16B
Is an infrared sensor 50 according to the tenth embodiment of the present invention.
3A and 3B are a plan view and a sectional view showing the structure of FIG. In the infrared sensor 50, a dielectric thin film 23 is provided on the upper surface of a silicon substrate 22, an etching hole 52 is partially opened in the dielectric thin film 23, and the upper surface of the silicon substrate 22 is etched through the etching hole 52. By etching, an annular concave portion 51 is formed on the upper surface of the silicon substrate 22, and the heat insulating thin film 25 is formed on the concave portion 51. Therefore, on the upper surface of the silicon substrate 22, the annular concave portion 51 is formed outside the central heat sink 26, and the outer peripheral side heat sink 27 is formed outside the concave portion 51.

A thermopile 30 having a zigzag pattern is formed between the upper side of the outer heat sink 27 and the heat insulating thin film 25 by alternately arranging the first thermoelectric material 28 and the second thermoelectric material 29. The first thermoelectric material 28 and the second thermoelectric material 29 of the thermopile 30 are joined on the outer heat sink 27 to form the cold junction 31, and the heat insulating thin film 25
The junction is formed above to form a hot junction 32. Further, a thermopile 30 having a zigzag pattern is formed between the heat insulating thin film 25 and above the central heat sink 26 by alternately wiring the first thermoelectric material 28 and the second thermoelectric material 29. The first thermoelectric material 28 and the second thermoelectric material 29 of the thermopile 30 are joined on the central heat sink 26 to form a cold junction 31, and joined on the heat insulating thin film 25 to form a hot junction 32. Electrodes 33 are provided at both ends of the thermopile 30 wired in zigzag. Furthermore, on the heat insulating thin film 25, Au,
An infrared absorber 34 made of metal black such as Bi is provided, and each hot junction 32 is covered with the infrared absorber 34.

In this embodiment, the silicon substrate 2
2 is etched from the upper surface side to form the concave portion 51, so that the entire manufacturing process can be performed only from the upper surface side of the silicon substrate 22, and the manufacturing process can be simplified.

(Eleventh Embodiment) FIGS. 17A and 17B
Is an infrared sensor 53 according to the eleventh embodiment of the present invention.
3A and 3B are a plan view and a sectional view showing the structure of FIG. In this infrared sensor 53, as shown in FIG. 18 (b), the silicon substrate 22 is etched from the rear side except for the central part and the outer peripheral part of the silicon substrate 22 having the dielectric thin film 23 formed on the upper surface. An annular cavity 24 is formed in the silicon substrate 22. Therefore, the heat insulating thin film 25 is formed on the outer periphery of the central heat sink 26, and the outer heat sink 27 is formed on the outer side thereof. Further, as shown in FIG. 18A, the inside of the central heat sink 26 is etched from an etching hole (not shown) formed in the dielectric thin film 23 to form a concave portion 51, and the upper surface of the concave portion 51 is also thermally insulated. The conductive thin film 25 is formed.

The thermopile shown in FIGS. 17A and 17B has the same pattern as that shown in FIG. 4A, but may have the same pattern as that shown in FIG. 2A.

As in this embodiment, the concave portion 51 etched from the upper surface and the cavity 2 etched from the lower surface are used.
In combination with 4, the taper directions of the side surfaces are opposite to each other, so that the silicon substrate can be made smaller.

(Twelfth Embodiment) FIGS. 19A and 19B
Is an infrared sensor 54 according to the twelfth embodiment of the present invention.
3A and 3B are a bottom view and a sectional view showing the structure of FIG. In the infrared sensor 54, the silicon substrate 22 is etched from the front side and the rear side except for the central portion and the outer peripheral portion of the silicon substrate 22 on which the dielectric thin film 23 is formed on the upper surface. A cavity 24 is formed. Therefore, the heat insulating thin film 25 is formed on the outer periphery of the central heat sink 26, and the outer heat sink 27 is formed on the outer side thereof. Although the pattern of the thermopile 30 is not shown, a pattern similar to any of the above-described embodiments may be used.

In this embodiment, since the cavity 24 is formed by etching from the front side and the back side, the etching time can be shortened.

[Brief description of the drawings]

FIGS. 1A and 1B are a plan view and a cross-sectional view showing the structure of a conventional thermopile infrared sensor.

FIG. 2 is a plan view showing the infrared sensor according to the first embodiment of the present invention.

FIGS. 3A and 3B are a bottom view and a cross-sectional view of the infrared sensor according to the embodiment.

FIGS. 4A and 4B are a plan view and a sectional view showing an infrared sensor according to a second embodiment of the present invention.

FIG. 5 is a plan view showing an infrared sensor according to a third embodiment of the present invention.

FIGS. 6A and 6B are a bottom view and a cross-sectional view of the infrared sensor according to the embodiment.

FIGS. 7A and 7B are a plan view and a sectional view showing an infrared sensor according to a fourth embodiment of the present invention.

FIG. 8 is a plan view illustrating an infrared sensor according to a fifth embodiment of the present invention.

FIGS. 9A and 9B are a bottom view and a cross-sectional view of the infrared sensor according to the embodiment.

FIG. 10 is a plan view showing an infrared sensor according to a sixth embodiment of the present invention.

FIGS. 11A and 11B are a bottom view and a cross-sectional view of the infrared sensor according to the embodiment.

FIG. 12 is a plan view illustrating an infrared sensor according to a seventh embodiment of the present invention.

FIGS. 13A and 13B are a bottom view and a cross-sectional view of the infrared sensor according to the embodiment.

FIGS. 14A and 14B are a plan view and a sectional view showing an infrared sensor according to an eighth embodiment of the present invention.

15A is a plan view illustrating an infrared sensor according to a ninth embodiment of the present invention, and FIG. 15B is a cross-sectional view taken along line XX of FIG.

FIGS. 16A and 16B are a plan view and a sectional view showing an infrared sensor according to a tenth embodiment of the present invention.

FIGS. 17 (a) and (b) are a plan view and a sectional view showing an infrared sensor according to an eleventh embodiment of the present invention.

18 (a) and (b) are a plan view and a bottom view of a silicon substrate used for the infrared sensor of the above.

FIGS. 19A and 19B are a bottom view and a sectional view showing an infrared sensor according to a twelfth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 22 silicon substrate 24 cavity 25, 25a, 25b heat insulating thin film 26 central heat sink 27, 27b outer heat sink 27a inner heat sink 30 thermopile 31 cold junction 32 hot junction 34 thermopile

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masakazu Shiiki O-Muron Co., Ltd. (72) Inventor Mikishi Danno 10 Hanazono Todo-cho, Ukyo-ku, Kyoto-shi, Kyoto Incorporated (72) Inventor Masaaki Sasaki 10th Hanazono Todocho, Ukyo-ku, Kyoto City, Kyoto Prefecture F-term (reference) 2G065 AB02 BA11 BA12 BA13 BA14 DA20 2G066 AC13 BA01 BA08 BA09 BA55

Claims (4)

[Claims] 1. A thermopile is wired on a hot junction forming area and a cold junction forming area of a substrate, a thermopile hot junction is arranged on a hot junction forming area, and a thermopile cold junction is formed on a cold junction forming area. An infrared sensor having contacts arranged therein, wherein a plurality of cold contact forming regions separated by a hot contact forming region are provided. 2. A thermopile is wired on the hot junction forming area and the cold junction forming area of the substrate, a thermopile hot junction is arranged on the hot junction forming area, and a thermopile cold junction is formed on the cold junction forming area. An infrared sensor having contacts arranged therein, wherein a plurality of hot junction forming regions separated by cold contact forming regions are provided. 3. A thermopile is wired on the hot junction forming area and the cold junction forming area of the substrate, the hot junction of the thermopile is arranged on the hot junction forming area, and the thermopile is cooled on the cold junction forming area. An infrared sensor having a contact disposed therein, wherein the cold junction formation region is formed by bending or crossing, and a thermopile is wired along substantially the entire outer edge of the cold junction formation region. 4. A thermopile is wired on the hot junction forming area and the cold junction forming area of the substrate, a thermopile hot junction is arranged on the hot junction forming area, and a thermopile cold junction is formed on the cold junction forming area. An infrared sensor having a contact, wherein the hot junction forming region is formed by bending or crossing, and a thermopile is wired along substantially the entire outer edge of the hot junction forming region.