Bolometer type detector and method for manufacturing the same

Abstract

To provide a bolometric detector which can reduce heat transfer between pixels.SOLUTION: The present invention relates to a bolometric detector including a plurality of pixels. The detector comprises at least: a substrate; a heat insulating layer placed on the substrate; a bolometer film of every pixel placed on the heat insulating layer; and wiring for signal output coupled to a contact electrode placed in contact with the bolometer film. The wiring for the signal output is disposed on a layer different from the bolometer film. The heat insulating layer between adjacent pixels is removed at least partially in the depth direction in an area of a length of 50% or more and a width of 100 nm or more of a closed curve surrounding the bolometer film.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a bolometer type detector and a method for manufacturing the same.

Background Art

[0002] Infrared sensors have a very wide range of applications, not only for security surveillance cameras, but also for human thermography, in-vehicle cameras, and inspections of structures, foods, etc. Therefore, in recent years, industrial applications have become active. In particular, the development of an inexpensive and high-performance infrared sensor capable of acquiring biological information in cooperation with IoT (Internet of Thing) is expected.

[0003] As an infrared sensor, a bolometer type uncooled infrared sensor using a titanium film or vanadium oxide as a resistance material is known (Patent Document 1). The bolometer described in Patent Document 1 has a diaphragm type heat insulation part 4 supported by leg parts 42 and separated from a silicon substrate 1 with a gap 7 on the silicon substrate 1, and an infrared detection part 3 is provided on this heat insulation part 4 (FIG. 15). When irradiated with infrared rays, the infrared detection part 3 is heated, and a resistance change due to a temperature change is detected. The gap 7 is evacuated to prevent heat from being transmitted to the silicon substrate 1 by heat conduction of air.

[0004] Such a bolometer having a diaphragm structure requires a complicated manufacturing process, and further, since the sensor needs to be vacuum-sealed and packaged, there is a problem that the cost cannot be avoided from increasing.

[0005] In response to such problems, a printed bolometer has been proposed (Patent Document 2). The bolometer described in Patent Document 2 has a structure that prevents heat conduction from the bolometer section (thermistor resistor) to the substrate by providing a heat insulation layer between the bolometer section and the substrate instead of the above-mentioned gap. Specifically, as shown in FIG. 16, a heat insulation layer 711 is provided on a substrate 710, and a light reflection film and a light transmission layer 713 are provided thereon. A first electrode 702, a second electrode 703, and a thermistor resistor 701 connected thereto are provided thereon. The first electrode 702 is connected to a column wiring 704, and the second electrode 703 is connected to a row wiring 705. The column wiring 704 and the row wiring 705 are electrically insulated by an insulating film 706. By adopting such a structure, there is an advantage that an array of bolometers can be formed without forming contacts.

[0006] Here, in the bolometer described in Patent Document 2, parylene is used as the heat insulation layer 711. Parylene has high heat insulation properties in the stacking direction but low heat insulation properties in the horizontal direction. Therefore, heat inflow between adjacent pixels easily occurs through the parylene surface, and there is a problem that heat inflow between adjacent pixels cannot be sufficiently suppressed. Further, as shown in FIG. 16, when metal column wirings 704 and row wirings 705 having high thermal conductivity are arranged between the bolometer films, heat inflow between pixels easily occurs in particular. When heat inflow between pixels occurs, there is a problem that a clear image cannot be obtained because heat is transmitted to adjacent pixels when the pixels are integrated into an array. Therefore, there is still a need for a bolometer type detector with reduced heat inflow between pixels.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a bolometer type detector in which heat inflow between pixels is reduced, and a method for manufacturing the same.

Means for Solving the Problems

[0009] One aspect of the present invention is a bolometer type detector including a plurality of pixels, a substrate, a heat insulating layer provided on the substrate, a bolometer film for each pixel provided on the heat insulating layer, and wiring for signal output connected to a contact electrode provided in contact with the bolometer film at least includes, the wiring for signal output is arranged in a layer different from the bolometer film, the heat insulating layer between adjacent pixels is at least partially removed in the depth direction in a region having a length of 50% or more of a closed curve surrounding the bolometer film and a width of 100 nm or more, relating to a detector.

[0010] Another aspect of the present invention is a method for manufacturing a bolometer type detector including a plurality of pixels, a step of forming a first heat insulating layer on a substrate, a step of forming one wiring for signal output on the first heat insulating layer, a step of forming a second heat insulating layer on the first heat insulating layer on which the wiring for signal output is formed, a step of forming the other wiring for signal output on the second heat insulating layer, a step of forming a third heat insulating layer on the second heat insulating layer on which the wiring for signal output is formed, a step of forming a bolometer film on the third heat insulating layer, a step of forming a contact electrode on the bolometer film, optionally, a step of forming a protective layer on the bolometer film on which the contact electrode is formed, A step of removing at least a part of the heat insulating layer between adjacent pixels in a region having a length of 50% or more of a closed curve surrounding the bolometer film and a width of 100 nm or more in the depth direction, and A step of connecting the contact electrodes to wirings for signal output respectively relates to a manufacturing method including the above.

Effect of the Invention

[0011] According to the present invention, a bolometer detector with reduced heat inflow between pixels can be provided.

Brief Description of the Drawings

[0012]

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Embodiments for Carrying Out the Invention

[0013] The bolometer type detector of the present invention has a feature that by removing at least a part of the heat insulating layer between pixels, the heat inflow between adjacent pixels can be reduced. Further, by providing a wiring layer having a high thermal conductivity in a layer different from the bolometer film, the heat inflow between pixels can be further reduced. Also, in one embodiment, by providing a wiring layer having a high thermal conductivity in a layer different from the bolometer film, it is not necessary to widen the interval between pixels, so that a higher fill factor can be realized. Further, according to the manufacturing method of the bolometer type detector of the present invention, particularly in a printed type bolometer detector, the heat inflow between pixels can be reduced by a simple process of removing at least a part of the heat insulating layer. Furthermore, in one embodiment, when removing the heat insulating layer by etching, by using a wiring layer disposed in a layer different from the bolometer film as an etch stop layer, a bolometer detector in which the heat insulating layer is pixel-separated can be manufactured by a simple process.

[0014] An example of the bolometer type detector and its manufacturing method according to the present embodiment will be described with reference to the drawings. In FIGS. 2 to 11, the central figure is a top view, the right figure is a cross-sectional view at the y1 - y1', y2 - y2', or y3 - y3' position, and the lower figure is a cross-sectional view at the x1 - x1' or x2 - x2' position. In FIGS. 1 and 12 to 14, the central figure is a top view, the right figure is a right side view when cut at the y1 - y1', y2 - y2', or y3 - y3' position, and the lower figure is a front view when cut at the x2 - x2' position. In addition, in FIGS. 1 to 14, an example is shown in which a parylene layer is used as the heat insulating layer, a carbon nanotube film is used as the bolometer film, an SiN layer is used as the protective layer, and the heat insulating layer is removed up to the vertical wiring or horizontal wiring or the depth of the substrate, but the bolometer type detector and its manufacturing method of the present invention are not limited to this configuration.

[0015] FIG. 1 shows a schematic of a bolometer type detector according to an embodiment. The bolometer type detector of this embodiment includes a first heat insulating layer (parylene first layer) 102-1 provided on a substrate 101, a wiring for signal output (vertical wiring) 103 provided on the first heat insulating layer 102-1, a second heat insulating layer (parylene second layer) 102-2 provided on the first heat insulating layer 102-1 where the wiring 103 for signal output is provided, a wiring for signal output (horizontal wiring) 104 provided on the second heat insulating layer 102-2, a third heat insulating layer (parylene third layer) 102-3 provided on the second heat insulating layer 102-2 where the wiring 104 for signal output is provided, a bolometer film (carbon nanotube film) 105 for each pixel provided on the third heat insulating layer 102-3, a pair of contact electrodes 106 connected to the bolometer film 105, and a protective film (SiN film) 107 provided on the bolometer film 105. The contact electrode 106 is connected to the wiring for signal output (vertical wiring 103 and horizontal wiring 104) by connection electrodes 109, respectively. Here, in the bolometer type detector of FIG. 1, the heat insulating layers between pixels (between adjacent bolometer films) are each removed to the depth of the wiring for signal output (vertical wiring 103 and horizontal wiring 104).

[0016] Thus, the bolometer type detector of this embodiment is characterized in that at least a part of the heat insulating layer between pixels is removed. The heat insulating layer 102 (in this specification, the heat insulating layers 102-1, 102-2, and 102-3 may be collectively referred to as the "heat insulating layer 102") only needs to have at least a part of the region of the heat insulating layer between pixels removed, but in the top view of each pixel, at least 50% or more, for example, 60% or more, preferably 70% or more, more preferably 80% or more, still more preferably 90% or more (it may be 100%) of the length of the closed curve surrounding the bolometer film region (the region of the bolometer film 105, the contact electrode 106, and the connection electrode 109) is preferably removed. The width removed at each point of the closed curve is at least 100 nm, preferably 500 nm or more, more preferably 1 μm or more. In one embodiment, it is preferable that the heat insulating layer is removed by the width of the heat insulating layer between pixels (that is, from the edge of the bolometer film region to the edge of the bolometer film region of the adjacent pixel). In one embodiment, it is preferable that the heat insulating layer is removed by the width of the heat insulating layer between pixels at 80% or more of the length of the closed curve. In one embodiment, as shown in FIG. 1, in all pixels, it is preferable that the heat insulating layer is removed by the width of the heat insulating layer between pixels over the entire length of the closed curve (100%) (that is, in all pixels, the heat insulating layer between pixels is removed over the entire region), so that the heat insulating layer is completely separated by pixels.

[0017] The closed curve surrounding the bolometer film region may be arranged at any position between two adjacent bolometer film regions. The closed curve may be amorphous, that is, at each point, it may be a straight line or any curve, but the length (%) of the non-removed region shall be converted as the shortest line connecting both ends of the non-removed region. The width removed at each point of the closed curve shall be the width in the direction perpendicular to the tangent of the closed curve at each point. It is also preferable that the closed curves of two adjacent pixels are shared in the region of the heat insulating layer between the two pixels.

[0018] Also, in the structure as shown in FIG. 1, there will be heat insulating layers on the four sides around each bolometer film region. From the viewpoint of uniformly reducing heat transfer, it is preferable that at least a part of the heat insulating layer is removed on at least two sides, preferably three or more sides, more preferably all four sides. Also, for the pixels arranged on the outer periphery of the bolometer array, there are no adjacent pixels on the outer side, but at least a part of the heat insulating layer on the side without adjacent pixels is also removed, similar to the side with adjacent pixels, that is, it is preferable that the outermost peripheral pixels are also heat-separated in the same way as other pixels. Thereby, by making the heat separation situation from the substrate of each pixel equal, the reaction speed of each pixel can be made more uniform.

[0019] In addition, in the region where the heat insulating layer 102 is removed, as long as at least a part of the depth from which the heat insulating layer is removed is removed in the depth direction from its surface (the upper surface of the parylene third layer in FIG. 1), the heat inflow through the surface of the heat insulating layer can be reduced. However, it is preferably removed from the surface to a depth of, for example, at least 100 nm or more, preferably at least 1 μm, more preferably at least 10 μm, and still more preferably at least 20 μm. In one embodiment, by removing the heat insulating layer to the respective depths of the signal extraction wirings (wirings for signal output), heat transfer between pixels can be further reduced.

[0020] An outline of an example of a method for manufacturing such a bolometer type detector will be described step by step with reference to the drawings.

[0021] Step 1: Substrate (FIG. 2) First, a substrate 101 is prepared. The substrate 101 may be either a flexible substrate or a rigid substrate and can be appropriately selected. However, at least the element formation surface is preferably insulating or semiconductive. For example, inorganic materials such as Si, Si coated with SiO2, SiO2, SiN, and glass, and organic materials such as polymers, resins, and plastics, such as parylene, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, acrylonitrile styrene resin, acrylonitrile butadiene styrene resin, fluororesin, methacrylic resin, and polycarbonate can be used, but are not limited thereto.

[0022] Step 2: Formation of the first heat insulating layer (FIG. 3) Next, a first heat insulating layer 102-1 is formed on the substrate 101. The heat insulation layer 102-1 and the heat insulation layers 102-2 and 102-3 described later are layers that block the heat transfer from the bolometer film 105 to the substrate 101. In a conventional bolometer, as shown in FIG. 15, a gap is provided as a structure for blocking the heat transfer from the bolometer film to the substrate, and a complicated manufacturing process is required for its formation. However, since the heat insulation layer in the present embodiment can be formed by a printing process or the like, a complicated manufacturing process is not required. Further, in a conventional bolometer, it is necessary to vacuum package the entire element in order to keep the gap vacuum, but the bolometer of the present embodiment also has the advantage that vacuum packaging is not required.

[0023] It is preferable to use a resin component having low thermal conductivity for the heat insulation layer 102-1. The thermal conductivity of the resin component used for the heat insulation layer is lower than the thermal conductivity of the substrate 101, and is, for example, in the range of 0.02 to 0.3 (W / mK), preferably 0.05 to 0.15 (W / mK). Further, in the bolometer type detector of the present embodiment in which the heat inflow between pixels is reduced by removing the heat insulation layer between pixels, if the heat insulation property in the vertical direction (lamination direction) is within a desired range, a material having low heat insulation property in the horizontal direction can also be adopted as the material of the heat insulation layer. Examples of such a resin component include, but are not limited to, parylene. Parylene is a general term for para-xylylene polymers and has a structure in which benzene rings are connected via CH2. Examples of parylene include parylene N, parylene C, parylene D, parylene HT, etc. Among them, parylene C (thermal conductivity: 0.084 (W / mK)) is most suitable because it has the lowest thermal conductivity.

[0024] The thickness of the heat insulation layer 102-1 may be appropriately set in consideration of the thermal conductivity of the component used. For example, when parylene such as parylene C is used, the thickness of the heat insulation layer 102-1 can be, for example, in the range of 100 nm to 30 μm, preferably 300 nm to 10 μm, more preferably 500 nm to 5 μm. Further, the total thickness of the heat insulation layer 102-1 and the heat insulation layers 102-2 and 102-3 described later can be, for example, in the range of 5 μm to 50 μm, preferably 10 μm to 20 μm.

[0025] The manufacturing method of the heat insulation layer 102-1 is not particularly limited and can be appropriately selected according to the material of the heat insulation layer. For example, when using a parylene film as the heat insulation layer, the parylene film can be formed by parylene coating a desired region using a vacuum evaporation apparatus. Specifically, when a solid dimer is heated under vacuum, it vaporizes to become a dimer gas. This gas thermally decomposes and the dimer cleaves to become a monomer form. In a deposition chamber at room temperature, this monomer gas polymerizes on all surfaces to form a thin and transparent polymer film. If necessary, before performing the deposition process, pretreatment of the substrate, cleaning of the substrate, masking of regions that should not be deposited, etc. may be performed.

[0026] Step 3: Formation of wiring for signal output (Figure 4) Next, a wiring (vertical wiring) 103 for signal output is formed. In the bolometer type detector of the present embodiment, a wiring for signal output made of metal (signal extraction wiring) is arranged in a layer different from the bolometer film. Thereby, heat transfer between pixels via a metal wiring having a high thermal conductivity can be reduced. Also, since each wiring can be arranged close to the bolometer film, a high fill factor can be achieved. As the material of the wiring for signal output, aluminum, gold, copper, tungsten, cobalt, and alloys thereof can be used. The wiring for signal output can be formed by vapor deposition or printing methods after patterning with a metal mask or the like if necessary.

[0027] Step 4: Formation of the second heat insulation layer 102-2 (Figure 5) Next, a second heat insulation layer 102-2 is formed on the first heat insulation layer 102-1 on which the formed wiring 103 for signal output is formed. The same material as that of the first heat insulation layer 102-1 may be used for the second heat insulation layer 102-2, or a different material may be used. The second heat insulation layer 102-2 can also function as an insulating layer that separates the wirings 103 and 104 for signal output. The thickness of the second heat insulation layer 102-2 can be appropriately selected according to the material used. For example, when using parylene such as parylene C, it can be in the range of 100 nm to 30 μm, preferably 300 nm to 10 μm, and more preferably 500 nm to 5 μm. The second heat insulation layer 102-2 can be formed in the same manner as the first heat insulation layer 102-1.

[0028] Step 5: Formation of Wiring for Signal Output (Fig. 6) Next, on the second heat insulation layer 102-2, another wiring (horizontal wiring) 104 for signal output is formed. The wiring 104 for signal output can be formed, for example, so as to be substantially perpendicular to the wiring (vertical wiring) 103 for signal output. The wiring 104 for signal output can be formed using the same material and method as the wiring 103 for signal output.

[0029] Step 6: Formation of the Third Heat Insulation Layer 102-3 (Fig. 7) Next, on the second heat insulation layer 102-2 on which the wiring 104 for signal output is formed, the third heat insulation layer 102-3 is formed. For the third heat insulation layer 102-3, the same material as the first heat insulation layer 102-1 or the second heat insulation layer 102-2 may be used, or a different material may be used. The thickness of the third heat insulation layer 102-3 can be appropriately selected according to the material used. For example, when using parylene such as parylene C, it can be in the range of 100 nm to 30 μm, preferably 300 nm to 10 μm, and more preferably 500 nm to 5 μm. The third heat insulation layer 102-3 can be formed in the same manner as the first heat insulation layer 102-1 or the second heat insulation layer 102-2.

[0030] Step 7: Formation of the Bolometer Film (Fig. 8) Next, a bolometer film 105 is formed on the third heat insulation layer 102-3. The bolometer type detector of this embodiment can be used for detecting a desired electromagnetic wave, and for the bolometer film, a thermoelectric conversion material can be appropriately selected and used according to the heat and electromagnetic wave to be detected. Examples of the material of the bolometer film include, in addition to the conventionally used titanium film and vanadium oxide film, organic thin films using organic materials (for example, carbon nanotube film, carbon nanohorn film, carbon nanobrush film), etc., but are not limited thereto.

[0031] As shown in FIG. 8, the bolometer film 105 may be separated into bolometer films for each pixel after forming a bolometer film layer over the entire substrate or over a plurality of pixels, or a bolometer film may be formed for each pixel.

[0032] In the bolometer type detector of this embodiment, since the wirings (vertical wiring 103 and horizontal wiring 104) for signal output made of metal are arranged in a layer different from the bolometer film 105, there is no need to increase the interval between pixels to prevent heat transfer between pixels, and a high fill factor can be achieved. Here, the interval between the bolometer films (the width of the heat insulation layer between pixels) is not particularly limited as long as at least the width where the above-described heat insulation layer is removed can be ensured. In one embodiment, the interval between the bolometer films (the width of the heat insulation layer between pixels) is preferably about the same as or greater than the depth where the above-described heat insulation layer is removed. Also, the upper limit is not particularly limited, but for example, it can be 20 μm or less, preferably 10 μm or less, and from the viewpoint of improving the fill factor, it is also preferably 5 μm or less. Also, the pixel pitch is not particularly limited and can be appropriately set in consideration of the required number of pixels, etc. From the viewpoint of the ease of the manufacturing process, 5 μm or more is preferable, 10 μm or more is more preferable, and from the viewpoint of high definition of the image, 100 μm or less is preferable, and 50 μm or less is more preferable.

[0033] An example of a preferable bolometer film, a carbon nanotube film, will be described later.

[0034] Step 8: Formation of Contact Electrodes (Fig. 9) Next, for each pixel, a contact electrode 106 is formed so as to contact the bolometer film 105. As shown in Fig. 9, the contact electrode 106 may be formed on the bolometer film 105 or may be formed under the bolometer film 105. The thickness of the contact electrode can be adjusted as appropriate, but is preferably 10 nm to 1 mm, more preferably 50 nm to 1 μm. Also, the electrode pitch is preferably 1 μm to 500 μm, and more preferably 5 to 200 μm for miniaturization. The contact electrode can be made of, for example, a single substance of gold, platinum, titanium, or a combination of a plurality thereof. The method for manufacturing the electrode is not particularly limited, and for example, it can be formed by vapor deposition, sputtering, or a printing method. If necessary, masking of regions where the contact electrode 106 should not be formed may be performed in advance.

[0035] Step 9: Formation of Protective Layer (Fig. 10) Next, a protective layer 107 is formed on the bolometer film 105. The protective layer has the effect of suppressing doping of the bolometer film (carbon nanotube film) due to adsorption of oxygen or the like, and may also have effects such as an increase in the light absorption rate by absorbing the light to be detected not only by the bolometer film but also by the protective layer. As the protective layer, materials used as protective layers in bolometers can be used without limitation, but materials having high transparency in the wavelength range to be detected are preferable. For example, in addition to silicon nitride (SiN) exemplified in Fig. 1, resins used for heat insulating layers, such as acrylic resins such as parylene, PMMA, and PMMA anisole, epoxy resins, Teflon (registered trademark), etc. can be mentioned, but are not limited thereto. The thickness of the protective layer can be, for example, 5 nm to 50 nm depending on the material. As shown in Fig. 10, the protective layer may be formed over the entire substrate or over a plurality of pixels and then separated for each pixel, or the protective layer may be formed for each pixel.

[0036] Step 10: Removal of Heat Insulating Layer (Figs. 11 to 13) Next, at least a part of the heat insulation layer 102 between adjacent pixels (between adjacent bolometer films) is removed. By removing at least a part of the heat insulation layer in this way (separating the heat insulation layer into pixels), the heat inflow between pixels through the heat insulation layer can be reduced.

[0037] The region and depth for removing the heat insulation layer are as described above. In one embodiment, it is preferable to remove the heat insulation layer to the depth of each of the signal extraction wirings. When the heat insulation layer is removed to the depth of the signal extraction wiring, the metal of the signal extraction wiring is exposed on the surface of the region where the heat insulation layer is removed (that is, the exposed metal also serves as a wiring for signal output), so there is no need to form a contact hole or the like when connecting the contact electrode and the signal extraction wiring with a connection electrode, and there is also an advantage that the manufacturing process becomes easy. Also, when removing the heat insulation layer by etching as described later, by using the metal signal extraction wiring as an etch stop layer, the heat insulation layer can be separated into pixels by a simple process. In addition, when the width of the signal extraction wiring is narrower than the width of the region between pixels, etc., in the region where there is no wiring, the heat insulation layer may be removed down to the substrate.

[0038] The method for removing at least a part of the heat insulation layer is not particularly limited, and examples include etching (dry etching, wet etching, etc.) and mechanical removal (dicer, drill, etc.). From the viewpoint of processing accuracy, dry etching, particularly anisotropic dry etching such as reactive ion etching (RIE), is preferable. When performing etching, an etching mask 108 is formed in advance on the area to be protected from etching as necessary. In one embodiment, by forming an etching mask on at least the area of the bolometer film of each pixel and performing etching, as shown in FIGS. 8 and 10, even when the bolometer film (and the protective layer) is formed over the entire substrate, the bolometer film (and the protective layer) can be separated into pixels simultaneously with the removal of the heat insulation layer between the pixels, and the manufacturing process can be simplified. The method for forming the etching mask is not particularly limited, and examples thereof include a method of forming a mask pattern with a metal such as gold by photolithography, and a method of forming a mask pattern with a photoresist.

[0039] Step 11: Formation of connection electrodes (FIG. 14) Next, the contact electrode 106 provided in contact with the bolometer film 105 and the signal extraction wirings 103 and 104 are respectively connected by connection electrodes 109. Examples of the material of the connection electrode 109 include a titanium film. The connection electrode 109 can be formed by vapor deposition, sputtering, or the like. When the heat insulation layer 102 exists at the position where the connection electrode is to be formed, contact holes or the like may be formed as necessary. A protective layer may be provided on the formed connection electrode 109.

[0040] Through the above steps, the bolometer type detector according to the present embodiment can be manufactured.

[0041] Hereinafter, as an example of the bolometer film 105, a carbon nanotube film will be described in detail. A bolometer type detector using a carbon nanotube film can be particularly preferably used for detecting electromagnetic waves having a wavelength of 0.7 μm to 1 mm. Examples of the electromagnetic waves included in the wavelength range include terahertz waves in addition to infrared rays. The bolometer type detector of the present embodiment is preferably an infrared sensor.

[0042] The carbon nanotube film as a bolometer film is a thin film composed of a plurality of carbon nanotubes that form a conductive path for electrically connecting contact electrode pairs. The carbon nanotubes can form structures such as parallel linear, fibrous, and network-like structures, etc. However, it is preferable that they form a three-dimensional network-like structure that is difficult to aggregate and can obtain a uniform conductive path.

[0043] Single-layer, bilayer, and multi-layer carbon nanotubes can be used for the carbon nanotubes. However, when separating the semiconductor type, single-layer or several layers (for example, 2 layers or 3 layers) of carbon nanotubes are preferable, and single-layer carbon nanotubes are more preferable. The carbon nanotubes preferably contain 80% by mass or more of single-layer carbon nanotubes, and more preferably contain 90% by mass or more (including 100% by mass).

[0044] From the viewpoint of increasing the bandgap and improving the TCR, the diameter of the carbon nanotubes is preferably between 0.6 and 1.5 nm, more preferably between 0.6 nm and 1.2 nm, and even more preferably between 0.7 and 1.1 nm. Also, in one embodiment, it may be particularly preferable that it is 1 nm or less. If it is 0.6 nm or more, the production of carbon nanotubes is easier. If it is 1.5 nm or less, it is easy to maintain the bandgap within an appropriate range and a high TCR can be obtained.

[0045] In this specification, the diameter of the carbon nanotubes means that when observing the carbon nanotubes on the heat insulation layer or in the formed thin film using an Atomic Force Microscope (AFM), the diameters at about 100 locations are measured, and 60% or more, preferably 70% or more, optionally preferably 80% or more, more preferably 100% are within the range of 0.6 to 1.5 nm. Preferably, 60% or more, preferably 70% or more, optionally preferably 80% or more, more preferably 100% are within the range of 0.6 to 1.2 nm, and even more preferably within the range of 0.7 to 1.1 nm. Also, in one embodiment, 60% or more, preferably 70% or more, optionally preferably 80% or more, more preferably 100% are within the range of 0.6 to 1 nm.

[0046] Also, in terms of the length of the carbon nanotubes, the range of 100 nm to 5 μm is more preferable because they are more easily dispersed and have excellent coatability. Also, from the perspective of the conductivity of the carbon nanotubes, it is preferable that the length is 100 nm or more. Also, if it is 5 μm or less, it is easy to suppress aggregation on the heat insulation layer and / or during film formation. The length of the carbon nanotubes is more preferably 500 nm to 3 μm, and even more preferably 700 nm to 1.5 μm.

[0047] In this specification, the length of the carbon nanotubes means that when observing at least 100 carbon nanotubes using an Atomic Force Microscope (AFM) and counting them, the length distribution of the carbon nanotubes is measured, and 60% or more, preferably 70% or more, optionally preferably 80% or more, more preferably 100% are within the range of 100 nm to 5 μm. Preferably, 60% or more, preferably 70% or more, optionally preferably 80% or more, more preferably 100% are within the range of 500 nm to 3 μm. More preferably, 60% or more, preferably 70% or more, optionally preferably 80% or more, more preferably 100% are within the range of 700 nm to 1.5 μm.

[0048] When the diameter and length of the carbon nanotubes are within the above ranges, the influence of the semiconducting property becomes significant, and a large current value can be obtained. Therefore, when used as the bolometer film, a high TCR value is likely to be obtained.

[0049] It is preferable to use semiconducting carbon nanotubes having a large bandgap and carrier mobility for the bolometer film. Among carbon nanotubes, the content of semiconducting carbon nanotubes, preferably semiconducting single-walled carbon nanotubes, is generally 67% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, particularly preferably 90% by mass or more, even more preferably 95% by mass or more, and still more preferably 99% by mass or more (including 100% by mass). In this specification, the ratio (mass %) of semiconducting carbon nanotubes in the carbon nanotubes may also be referred to as "semiconductor purity".

[0050] The thickness of the bolometer film is not particularly limited. For example, it is 1 nm or more, for example, several nm to 100 μm, preferably 10 nm to 10 μm, and more preferably in the range of 50 nm to 1 μm. In one embodiment, it is preferably in the range of 20 nm to 500 nm, and more preferably in the range of 50 nm to 200 nm. When the thickness of the bolometer film is 1 nm or more, a good light absorption rate can be obtained. Also, when the thickness of the bolometer film is 10 nm or more, preferably 50 nm or more, a sufficient light absorption rate can be obtained without providing a light reflection layer or a light absorption material layer, so that the element structure can be simplified. Also, when the thickness of the bolometer film is 1 μm or less, preferably 500 nm or less, it is preferable from the viewpoint of simplifying the manufacturing method. Also, if the bolometer film is too thick, the contact electrode vapor-deposited from above may not sufficiently contact the carbon nanotubes below the bolometer film, and the effective resistance value may increase. However, if it is within the above range, an increase in the resistance value can be suppressed. In addition, when providing a light reflection layer or a light absorption material layer, the thickness of the bolometer film may be made thinner than the above range to further simplify the manufacturing process and improve the resistance value. Also, when the thickness of the bolometer film is within the range of 10 nm to 1 μm as described above, it is also preferable in that printing technology can be suitably applied as a method for manufacturing the bolometer film.

[0051] The thickness of the bolometer film can be determined as the average value of the thicknesses measured at any 10 points of the bolometer film.

[0052] Also, the density of the bolometer film is, for example, 0.3 g / cm 3 or more, preferably 0.8 g / cm 3 or more, more preferably 1.1 g / cm 3 or more. The upper limit is not particularly limited, but can be the upper limit value of the true density of the carbon nanotubes used (for example, about 1.4 g / cm 3 ). When the density of the bolometer film is 0.3 g / cm 3 or more, a good light absorption rate can be obtained. Also, when the density of the bolometer film is 0.5 g / cm 3 or more, it is preferable in that a sufficient light absorption rate can be obtained without providing a light reflection layer or a light absorption material layer, and the element structure can be simplified. In addition, when providing a light reflection layer or a light absorption material layer, a lower density than the above may be appropriately selected as the density of the bolometer film.

[0053] The density of the bolometer film can be calculated from the weight, area, and thickness obtained above of the bolometer film.

[0054] Also, in the bolometer film, in addition to the above-described components, for example, a negative thermal expansion material, an ion conductive agent (surfactant, ammonium salt, inorganic salt), a resin, an organic binder, etc. described later may be appropriately used.

[0055] The content of carbon nanotubes in the bolometer film can be appropriately selected. Preferably, 0.1% by mass or more based on the total mass of the bolometer film is effective, more preferably 1% by mass or more is effective. For example, it can be 30% by mass, and even more preferably 50% by mass or more, and in some cases 60% by mass or more may be preferred.

[0056] Hereinafter, an example of the method for manufacturing a carbon nanotube film will be described in detail.

[0057] The carbon nanotubes may be those obtained by removing impurities such as surface functional groups and amorphous carbon, and catalysts, etc. by performing heat treatment in an inert atmosphere under vacuum. The heat treatment temperature can be appropriately selected, but 800 - 2000 °C is preferred, and 800 - 1200 °C is more preferred.

[0058] The nonionic surfactant can be appropriately selected. It is preferable to use one or a combination of a plurality of nonionic surfactants composed of a hydrophilic moiety that does not ionize and a hydrophobic moiety such as an alkyl chain, such as a nonionic surfactant having a polyethylene glycol structure typified by polyoxyethylene alkyl ether, or an alkyl glucoside-based nonionic surfactant. As such a nonionic surfactant, polyoxyethylene alkyl ether represented by the formula (1) is preferably used. Also, the alkyl part may contain one or more unsaturated bonds.

[0059] C n H 2n+1 (OCH2CH2) m OH (1) (In the formula, n is preferably 12 - 18, m is 10 - 100, preferably 20 - 100)

[0060] Particularly, nonionic surfactants defined by polyoxyethylene(n) alkyl ethers such as polyoxyethylene(23) lauryl ether, polyoxyethylene(20) cetyl ether, polyoxyethylene(20) stearyl ether, polyoxyethylene(10) oleyl ether, polyoxyethylene(10) cetyl ether, polyoxyethylene(10) stearyl ether, polyoxyethylene(20) oleyl ether, polyoxyethylene(100) stearyl ether (where n is 20 or more and 100 or less, and the alkyl chain length is C12 or more and C18 or less) are more preferable. Also, N,N-bis[3-(D-gluconamido)propyl]deoxycholamide, n-dodecyl β-D-maltoside, octyl β-D-glucopyranoside, and digitonin can also be used.

[0061] As nonionic surfactants, polyoxyethylene sorbitan monostearate (molecular formula: C 64 H 126 O 26 , trade name: Tween 60, manufactured by Sigma-Aldrich, etc.), polyoxyethylene sorbitan trioleate (molecular formula: C 24 H 44 O6, trade name: Tween 85, manufactured by Sigma-Aldrich, etc.), octylphenol ethoxylate (molecular formula: C 14 H 22 O(C2H4O) n , n = 1 to 10, trade name: Triton X-100, manufactured by Sigma-Aldrich, etc.), polyoxyethylene(40) isooctylphenyl ether (molecular formula: C8H 17 C6H 40 (CH2CH 20 ) 40 H, trade name: Triton X-405, manufactured by Sigma-Aldrich, etc.), poloxamer (molecular formula: C5H 10 O2, trade name: Pluronic, manufactured by Sigma-Aldrich, etc.), polyvinylpyrrolidone (molecular formula: (C6H9NO) n , n = 5 to 100, manufactured by Sigma-Aldrich, etc.), etc. can also be used.

[0062] The method for obtaining a dispersion solution of carbon nanotubes is not particularly limited, and conventionally known methods can be applied. For example, a carbon nanotube mixture, a dispersion medium, and a nonionic surfactant are mixed to prepare a solution containing carbon nanotubes, and this solution is ultrasonicated to disperse the carbon nanotubes, thereby preparing a carbon nanotube dispersion (micelle dispersion solution). The dispersion medium is not particularly limited as long as it can disperse and suspend carbon nanotubes during the separation process. For example, water, heavy water, an organic solvent, an ionic liquid, or a mixture thereof can be used, but water and heavy water are preferred. In addition to or instead of the ultrasonic treatment, a carbon nanotube dispersion method using mechanical shear force may be used. The mechanical shearing may be performed in the gas phase. In the micelle-dispersed aqueous solution of carbon nanotubes and a nonionic surfactant, it is preferable that the carbon nanotubes are in an isolated state. Therefore, if necessary, ultracentrifugation treatment may be used to remove bundles, amorphous carbon, impurity catalysts, etc. During the dispersion treatment, the carbon nanotubes can be cut, and the length can be controlled by changing the grinding conditions, ultrasonic output, ultrasonic treatment time, etc. of the carbon nanotubes. For example, untreated carbon nanotubes can be ground with tweezers, a ball mill, etc. to control the aggregate size. After these treatments, by using an ultrasonic homogenizer, the output is 40 - 600 W, in some cases 100 - 550 W, 20 - 100 KHz, and the treatment time is 1 - 5 hours, preferably ~3 hours, the length can be controlled to 100 nm - 5 μm. If it is shorter than 1 hour, depending on the conditions, it may hardly disperse and may remain almost the original length. Also, from the viewpoints of shortening the dispersion treatment time and reducing costs, 3 hours or less is preferable. This embodiment may also have the advantage that the adjustment of cutting is easy due to the use of a nonionic surfactant. It also has the advantage of not containing an ionic surfactant that is difficult to remove.

[0063] By dispersing and cutting carbon nanotubes, surface functional groups are generated on the surface or ends of the carbon nanotubes. The functional groups generated include carboxyl groups, carbonyl groups, hydroxyl groups, etc. In the case of liquid-phase treatment, carboxyl groups and hydroxyl groups are generated, and in the case of gas-phase treatment, carbonyl groups are generated.

[0064] Also, the concentration of the surfactant in the liquid containing the heavy water or water and the nonionic surfactant is preferably from the critical micelle concentration to 10% by mass, more preferably from the critical micelle concentration to 3% by mass. It is not preferable because dispersion cannot be achieved below the critical micelle concentration. Also, if it is 10% by mass or less, a sufficient density of carbon nanotubes can be applied while reducing the amount of the surfactant after separation. In this specification, the critical micelle concentration (CMC) refers to, for example, the concentration at the inflection point when the surface tension is measured by changing the concentration of an aqueous surfactant solution using a surface tensiometer such as a Wilhelmy type surface tensiometer at a constant temperature. In this specification, the "critical micelle concentration" is taken as the value at 25°C under atmospheric pressure.

[0065] The concentration of carbon nanotubes in the above cutting and dispersion step (weight of carbon nanotubes / (total weight of dispersion medium and surfactant) × 100) is not particularly limited, but can be, for example, 0.0003 to 10% by mass, preferably 0.001 to 3% by mass, more preferably 0.003 to 0.3% by mass.

[0066] The dispersion obtained through the above cutting and dispersion step may be used as it is in the separation step described later, or steps such as concentration and dilution may be performed before the separation step.

[0067] The separation of carbon nanotubes can be carried out, for example, by an electric field-induced layer formation method (ELF method: see, for example, K. Ihara et al. J. Phys. Chem. C. 2011, 115, 22827-22832, Japanese Patent No. 5717233, these documents are incorporated herein by reference). An example of a separation method using the ELF method will be described. Carbon nanotubes, preferably single-walled carbon nanotubes, are dispersed with a nonionic surfactant, and the dispersion is placed in a vertical separation device, and a voltage is applied to the electrodes arranged vertically and horizontally, and separation is carried out by carrier-free electrophoresis. The separation mechanism can be estimated as follows, for example. When carbon nanotubes are dispersed with a nonionic surfactant, the micelles of semiconducting carbon nanotubes have a negative zeta potential, while the micelles of metallic carbon nanotubes have a zeta potential of the opposite sign (positive) (in recent years, it is also considered that they have a slightly negative zeta potential or are hardly charged). Therefore, when an electric field is applied to the carbon nanotube dispersion, due to the difference in zeta potential, etc., the conducting carbon nanotube micelles electrophorese in the anode (+) direction, and the metallic carbon nanotube micelles electrophorese in the cathode (-) direction. Finally, a layer in which semiconducting carbon nanotubes are concentrated is formed near the anode, and a layer in which metallic carbon nanotubes are concentrated is formed in the separation tank near the cathode. The separation voltage can be appropriately set in consideration of the composition of the dispersion medium, the charge amount of the carbon nanotubes, etc., but is preferably 1 V or more and 200 V or less, and more preferably 10 V or more and 200 V or less. From the viewpoint of shortening the time of the separation process, 100 V or more is preferable. Also, from the viewpoint of suppressing the generation of bubbles during separation and maintaining the separation efficiency, 200 V or less is preferable. The separation can be repeated to improve the purity. The dispersion after separation may be reset to the initial concentration and the same separation operation may be performed. Thereby, further purification can be achieved.

[0068] By the above-described carbon nanotube dispersion / cutting step and separation step, a dispersion liquid in which semiconducting carbon nanotubes having a desired diameter and length are concentrated can be obtained. In the present specification, a carbon nanotube dispersion liquid in which semiconducting carbon nanotubes are concentrated may be referred to as a "semiconducting carbon nanotube dispersion liquid". The semiconducting carbon nanotube dispersion liquid obtained by the separation step means a dispersion liquid containing semiconducting carbon nanotubes generally at 67% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, particularly preferably 90% by mass or more, more preferably 95% by mass or more, and still more preferably 99% by mass or more (the upper limit may be 100% by mass) in the total amount of carbon nanotubes. The separation tendency of metallic and semiconducting carbon nanotubes can be analyzed by microscopic Raman spectrum analysis and ultraviolet-visible near-infrared absorption photometry.

[0069] After the above-described carbon nanotube dispersion / cutting step and before the separation step, a centrifugation treatment may be performed to remove bundles, amorphous carbon, metal impurities, etc. of the carbon nanotube dispersion liquid. The centrifugal acceleration can be adjusted as appropriate, but is preferably 10,000×g to 500,000×g, more preferably 50,000×g to 300,000×g, and may be 100,000×g to 300,000×g in some cases. The centrifugation time is preferably 0.5 hour to 12 hours, and more preferably 1 to 3 hours. The centrifugation temperature can be adjusted as appropriate, but is preferably 4°C to room temperature, and more preferably 10°C to room temperature.

[0070] The concentration of the surfactant in the carbon nanotube dispersion liquid after separation can be controlled as appropriate. The concentration of the surfactant in the carbon nanotube dispersion liquid is preferably from the critical micelle concentration to about 5% by mass, more preferably 0.001% by mass to 3% by mass, and particularly preferably 0.01 to 1% by mass in order to suppress re-aggregation after coating.

[0071] The semiconductor carbon nanotube dispersion obtained by the above process can be applied onto a heat insulating layer or a predetermined substrate, dried, and optionally heat-treated to form a bolometer film.

[0072] The method of applying the semiconductor carbon nanotube dispersion onto the heat insulating layer or a predetermined substrate is not particularly limited, and examples thereof include a dropping method, spin coating, printing, inkjet, spray coating, dip coating, etc. From the viewpoint of reducing manufacturing costs, the printing method is preferred. Examples of the printing method include coating (dispenser, inkjet, etc.), transfer (microcontact printing, gravure printing, etc.).

[0073] The surfactant and the solvent can be removed from the semiconductor carbon nanotube dispersion applied onto the heat insulating layer or a predetermined substrate by heat treatment. The temperature of the heat treatment can be appropriately set to be equal to or higher than the decomposition temperature of the surfactant, but is preferably 150 to 500°C, more preferably 200 to 500°C, for example, 200 to 400°C. If it is 200°C or higher, it is more preferable because it is easy to suppress the residue of the decomposition product of the surfactant. Further, if it is 500°C or lower, for example, 400°C or lower, it is preferable because it is possible to suppress the alteration of the substrate and other components. Further, it is possible to suppress the decomposition, size change, and detachment of functional groups of the carbon nanotubes.

[0074] (Negative thermal expansion material) In one embodiment, the bolometer film can contain a negative thermal expansion material in addition to the carbon nanotubes. The bolometer film according to this embodiment is a carbon nanotube composite material in which a negative thermal expansion material is dispersed in a carbon nanotube aggregate having a three-dimensional network structure that constitutes a network structure formed by entangled and aggregated dispersed carbon nanotubes. Such a three-dimensional conductive network of carbon nanotubes is not all connected and contributes to conduction in the bolometer material, and some carbon nanotubes do not contribute to the conduction mechanism. These carbon nanotubes construct new conduction paths due to the effect of the volume reduction of the negative thermal expansion material accompanying the temperature rise. Or, due to the effect of the volume reduction, the contact area between carbon nanotubes increases, and furthermore, the conduction paths also increase. As a result, the increase in current accompanying the temperature rise becomes larger, and the TCR value improves. That is, since the negative thermal expansion material mixed with the semiconducting carbon nanotubes contracts as the temperature rises, a network of carbon nanotubes that were separated from each other is additionally generated at that time, the number of conduction paths increases, and more current flows. Further, in one embodiment, by using a negative thermal expansion material having a higher resistance than the semiconducting carbon nanotubes, the conduction paths of the semiconducting carbon nanotubes can be formed more efficiently.

[0075] In this specification, the negative thermal expansion material means a material having a negative expansion coefficient that contracts as the temperature rises. Examples of the negative thermal expansion material include, for example, in any temperature range from -100 to +200 °C, for example, in the range from -100 to +100 °C, preferably in the temperature range of use of the bolometer, for example, at least from -50 to 100 °C, the linear thermal expansion coefficient ΔL / L per 1 K temperature difference ((length after expansion - length before expansion) / length before expansion) is preferably -1×10 -6 / K to -1×10 -3 / K, more preferably -1×10 -5 / K to -1×10 -3 / K. The thermal expansion coefficient can be measured, for example, in accordance with JIS Z 2285 (Method for Measuring Linear Expansion Coefficient of Metallic Materials) or JIS R 1618 (Method for Measuring Thermal Expansion by Thermomechanical Analysis of Fine Ceramics).

[0076] In one embodiment, the negative thermal expansion material is preferably a material that exhibits sufficient negative thermal expansion in the usage environment of the bolometer. The temperature of the usage environment of the bolometer is, for example, -350°C to 100°C, preferably -40°C to 80°C, and in some cases more preferably 20°C to 30°C, such as 21°C to 30°C. Also, as for the humidity of the usage environment of the bolometer, for example, when used in a structure where the bolometer part is open to the atmosphere, it may be the environmental humidity, and for example, 75%RH or less is preferable. Also, when used in a structure that is vacuum packaged or has an inert gas introduced into the package, for example, 5%RH or less is preferable, but depending on the degree of vacuum, etc., it may be outside the above range. From the perspective of the long-term stability of the device, a lower humidity is preferable, so the lower limit is not particularly limited in any case, and it is 0%RH or more, for example, more than 0%RH.

[0077] Also, the resistivity of the negative thermal expansion material is not particularly limited, but in an arbitrary temperature range of -100 to +100°C, preferably the operating temperature of the bolometer, for example, room temperature (about 23°C), it is 10 Ωcm to 10 8 Ωcm, preferably 10 2 Ωcm to 10 7 Ωcm. The resistivity can be measured according to standard methods such as JIS K 7194, JIS K 6911, etc.

[0078] In this specification, examples of the negative thermal expansion material include, but are not limited to, oxides, nitrides, sulfides, or multi-element compounds containing any one or more of Li, Al, Fe, Ni, Co, Mn, Bi, La, Cu, Sn, Zn, V, Zr, Pb, Sm, Y, W, Si, P, Ru, Ti, Ge, Ca, Ga, Cr, Cd. A mixture of two or more compounds may also be used. Examples of the negative thermal expansion materials include, but are not limited to, vanadium oxides, β-eucryptite, bismuth nickel oxides, zirconium tungstenates, ruthenium oxides, manganese nitrides, lead titanates, samarium monosulfide, etc. (including those in which one or more elements of these compounds are replaced with the above elements). For example, LiAlSiO4, ZrW2O8, Zr2WO4(PO4)2, BiNi 0.85 Fe 0.15 O3, Bi 0.95 La 0.05 NiO3, Pb 0.76 La 0.04 Bi 0.20 VO3, Sm 0.78 Y 0.22 S, Cu 1.8 Zn 0.2 V2O7, Cu2V2O7, 0.4PbTiO3-0.6BiFeO3, MnCo 0.98 Cr 0.02 Ge, Ca2RuO 3.74 , Mn3Ga 0.7 Ge 0.3 N 0.88 C 0.12 , Cd(CN)2·xCCl4, LaFe 10.5 Co 1.0 Si 1.5 , Ca2RuO4, Mn 3.27 Zn 0.45 Sn 0.28 N, Mn3Ga 0.9 Sn 0.1 N 0.9 , Mn3ZnN are suitable.

[0079] In one embodiment, among the negative thermal expansion materials, oxides, nitrides, and sulfides are preferred from the viewpoints of ease of synthesis and availability.

[0080] In this specification, the size of the negative thermal expansion material can be appropriately selected. Preferably, it is 10 nm to 100 μm, more preferably 15 nm to 10 μm, and in some cases, it is also preferably 50 nm to 5 μm. Also, the form of the negative thermal expansion material is not particularly limited, and examples include spherical, needle-like, rod-like, plate-like, fibrous, flaky, etc. From the viewpoint of film-forming property, spherical is preferred.

[0081] In addition, the content of the negative thermal expansion material in the bolometer film can be appropriately selected, but it is preferably contained in an amount of 1 to 99% by mass, more preferably 1 to 70% by mass, based on the total mass of the bolometer film. For example, it is preferably 1 to 50% by mass, and in some cases, it is also preferably 10 to 50% by mass. In some cases, it is preferably 40% by mass or less.

[0082] In addition to the carbon nanotubes and the negative thermal expansion material, the bolometer film may contain a binder and, if desired, other components. However, the total mass of the carbon nanotubes and the negative thermal expansion material is preferably 70% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the mass of the bolometer film.

[0083] The bolometer film containing carbon nanotubes and a negative thermal expansion material can be manufactured by using a dispersion obtained by adding a negative thermal expansion material, a binder, etc., if necessary, to the carbon nanotube dispersion in the method for manufacturing a bolometer film using the above carbon nanotube dispersion.

[0084] In addition to the above components, the bolometer type detector of the present embodiment can further be provided with any components that the bolometer can include.

[0085] <Light reflection layer> A light reflection layer may be provided in the bolometer type detector of the present embodiment in order to improve the absorption rate of the electromagnetic wave to be detected. The light reflection layer can be provided between the bolometer film 105 and the substrate 101, for example, between the heat insulating layer 102. The light reflection layer is preferably disposed at a position where the distance d between the bolometer film 105 and the light reflection layer is d = λ / 4 in consideration of the wavelength λ of the electromagnetic wave to be absorbed. As the light reflection layer, materials used as the light reflection layer in a bolometer can be used without limitation. Generally, metals such as gold, silver, aluminum, etc. can be mentioned, and it can be formed by vapor deposition, sputtering, plating, etc.

[0086] <Light absorption material layer> In the bolometer type detector of the present embodiment, a light absorption material layer may be provided to improve the absorption rate of the electromagnetic wave to be detected. The light absorption material layer can be provided on the side where the electromagnetic wave to be detected is incident, for example, on the upper side of the bolometer film 105 or the protective layer 107. The thickness of the light absorption material layer can be appropriately set according to the material, but can be, for example, 50 nm to 1 μm. As the light absorption material layer, a material used as the light absorption material layer in the bolometer can be used without particular limitation, and examples include a coated film of polyimide, a titanium nitride thin film, and the like.

[0087] In addition to the above, in the bolometer type detector and its manufacturing method of the present embodiment, except for the point of removing a part of the heat insulating layer and the point of arranging the wiring for signal output in a layer different from the bolometer film, the configuration and manufacturing method used for the bolometer type detector, particularly the printed type bolometer type detector, can be applied without particular limitation.

[0088] For example, although a simple matrix type bolometer type detector is shown above, the bolometer type detector of the present embodiment may be an active matrix type array such as a TFT (thin film transistor) array.

[0089] Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

[0090] Some or all of the above embodiments may be described as follows in the appended claims, but are not limited thereto. [Appended Claim 1] A bolometer type detector including a plurality of pixels, a substrate, a heat insulating layer provided on the substrate, a bolometer film for each pixel provided on the heat insulating layer, and A wiring for signal output connected to a contact electrode provided in contact with the bolometer film comprising at least the wiring for signal output is disposed in a layer different from the bolometer film, a detector in which an insulating layer between adjacent pixels is at least partially removed in the depth direction in a region having a length of 50% or more of a closed curve surrounding the bolometer film and a width of 100 nm or more. [Appendix 2] The detector according to Appendix 1, wherein the insulating layer is a parylene layer. [Appendix 3] The detector according to Appendix 1 or 2, wherein the bolometer film contains an organic material. [Appendix 4] The detector according to any one of Appendices 1 to 3, wherein the bolometer film contains semiconducting carbon nanotubes. [Appendix 5] The detector according to any one of Appendices 1 to 4, wherein the bolometer film contains semiconducting carbon nanotubes and a negative thermal expansion material. [Appendix 6] The detector according to any one of Appendices 1 to 5, further comprising a light absorbing layer on the upper side of the bolometer film. [Appendix 7] The detector according to any one of Appendices 1 to 6, wherein metal is exposed on the surface of the region where the insulating layer is removed. [Appendix 8] The detector according to Appendix 7, wherein the exposed metal also serves as a wiring for signal output. [Appendix 9] A method for manufacturing a bolometer type detector including a plurality of pixels, comprising: forming a first insulating layer on a substrate; forming one wiring for signal output on the first insulating layer; forming a second insulating layer on the first insulating layer on which the wiring for signal output is formed; forming the other wiring for signal output on the second insulating layer; forming a third insulating layer on the second insulating layer on which the wiring for signal output is formed; forming a bolometer film on the third insulating layer; A step of forming a contact electrode on a bolometer film, Optionally, a step of forming a protective layer on the bolometer film on which the contact electrode is formed, A step of removing at least a part in the depth direction of the heat insulating layer between adjacent pixels in a region having a length of 50% or more of a closed curve surrounding the bolometer film and a width of 100 nm or more, and A step of connecting each contact electrode to a wiring for signal output A manufacturing method including these steps. [Appendix 10] A step of forming a first heat insulating layer on a substrate, A step of forming one wiring for signal output on the first heat insulating layer, A step of forming a second heat insulating layer on the first heat insulating layer on which the wiring for signal output is formed, A step of forming the other wiring for signal output on the second heat insulating layer, A step of forming a third heat insulating layer on the second heat insulating layer on which the wiring for signal output is formed, A step of forming a bolometer film layer on the third heat insulating layer, A step of forming a contact electrode for each pixel on the bolometer film layer, A step of forming a protective layer on the bolometer film layer on which the contact electrode is formed, A step of forming an etching mask covering a region to be a bolometer film for each pixel on the protective layer, A step of removing at least a part in the depth direction of the heat insulating layer between adjacent pixels in a region having a length of 50% or more of a closed curve surrounding the bolometer film and a width of 100 nm or more by etching, A step of removing the etching mask, and A step of connecting each contact electrode to a wiring for signal output The manufacturing method according to Appendix 9 including these steps. [Appendix 11] The manufacturing method according to Appendix 10 including a step of removing the heat insulating layer between adjacent pixels by etching to the depth of the wiring for signal output.

Explanation of reference numerals

[0091] 101 Substrate 102 Heat insulation layer 102-1 First heat insulation layer 102-2 Second heat insulation layer 102-3 Third heat insulation layer 103 Wiring for signal output (vertical wiring) 104 Wiring for signal output (horizontal wiring) 105 Bolometer film 106 Contact electrode 107 Protective layer 108 Etching mask 109 Connection electrode 1 Base substrate 3 Temperature detection part 4 Heat insulation part 6 Infrared reflection film 7 Gap 42 Leg part 701 Thermistor resistor 702 First electrode 703 Second electrode 704 Column wiring 705 Braid wiring 706 Insulating film 710 Substrate 711 Heat insulation layer 712 Light reflection film 713 Light transmission layer

Claims

1. A bolometer type detector comprising a plurality of pixels, a substrate, a heat insulation layer provided on the substrate, a bolometer film for each pixel provided on the heat insulation layer, and wiring for signal output connected to a contact electrode provided in contact with the bolometer film at least, the wiring for signal output is disposed in a layer different from the bolometer film, the heat insulation layer between adjacent pixels is removed at least partially in the depth direction in a region having a length of 50% or more of a closed curve surrounding the bolometer film and a width of 100 nm or more, a detector in which the heat insulation layer between the substrate and the bolometer film does not contain voids.

2. The detector according to claim 1, wherein the heat insulation layer is a parylene layer.

3. The detector according to claim 1 or 2, wherein the bolometer film contains an organic material.

4. The detector according to any one of claims 1 to 3, wherein the bolometer film contains semiconducting carbon nanotubes.

5. The detector according to any one of claims 1 to 4, wherein the bolometer film contains semiconducting carbon nanotubes and a negative thermal expansion material.

6. The detector according to any one of claims 1 to 5, further comprising a light absorption material layer on the upper side of the bolometer film.

7. The detector according to any one of claims 1 to 6, wherein metal is exposed on the surface of the region where the heat insulation layer is removed.

8. The detector according to claim 7, wherein the exposed metal also serves as wiring for signal output.

9. A method for manufacturing a bolometer type detector comprising a plurality of pixels, a step of forming a first heat insulation layer on a substrate, a step of forming one wiring for signal output on the first heat insulation layer, a step of forming a second heat insulation layer on the first heat insulation layer on which the wiring for signal output is formed, a step of forming the other wiring for signal output on the second heat insulation layer, a step of forming a third heat insulation layer on the second heat insulation layer on which the wiring for signal output is formed, a step of forming a bolometer film on the third heat insulation layer, a step of forming a contact electrode on the bolometer film, a step of forming a protective layer on the bolometer film on which the contact electrode is formed, a step of removing at least partially in the depth direction the heat insulation layer between adjacent pixels in a region having a length of 50% or more of a closed curve surrounding the bolometer film and a width of 100 nm or more, and a step of connecting each contact electrode to the wiring for signal output including.

10. A step of forming a first heat insulation layer on a substrate, A step of forming one wiring for signal output on the first heat insulation layer, A step of forming a second heat insulation layer on the first heat insulation layer on which the wiring for signal output is formed, A step of forming the other wiring for signal output on the second heat insulation layer, A step of forming a third heat insulation layer on the second heat insulation layer on which the wiring for signal output is formed, A step of forming a bolometer film layer on the third heat insulation layer, A step of forming contact electrodes for each pixel on the bolometer film layer, A step of forming a protective layer on the bolometer film layer on which the contact electrodes are formed, A step of forming an etching mask on the protective layer to cover the region to be the bolometer film for each pixel, A step of removing at least a part in the depth direction of the heat insulation layer between adjacent pixels in a region having a length of 50% or more of the closed curve surrounding the bolometer film and a width of 100 nm or more by etching, A step of removing the etching mask, and A step of connecting the contact electrodes to the wirings for signal output respectively The manufacturing method according to claim 9, comprising

Images