Infrared sensor

Abstract

The present invention provides an infrared sensor comprising: a substrate; a plurality of thermocouple modules arranged on one surface of the substrate; and an electrode arranged on one surface of the substrate, wherein the plurality of thermocouple modules comprise a first material, a second material, and an infrared absorption layer arranged on the first material and the second material, the first material and the second material comprise a hot region of an upper portion and a cold region of a lower portion, the infrared absorption layer is arranged in the hot regions of the upper portions of the first material and the second material, the electrode comprises a first electrode arranged in the hot region of the upper portion of the thermocouple module and a second electrode formed in the cold region, and the first material and the second material comprise an empty cavity layer between the upper portion and the substrate.

Description

infrared sensor

[0001] The present invention relates to an infrared sensor.

[0002] Infrared sensors are generally used to detect radiant energy emitted from objects. Infrared sensors can be categorized into semiconductor and thermal types, depending on how they detect infrared. While semiconductor sensors exhibit varying characteristics depending on the infrared wavelength, thermal sensors exhibit consistent performance regardless of the wavelength.

[0003] Among thermal sensors, thermopile sensors can be manufactured using existing semiconductor processes, do not require cooling, and are inexpensive yet reliable, so research on them is actively being conducted.

[0004] A thermopile sensor is a sensor that detects temperature by utilizing the Seebeck effect, which generates thermoelectric power proportional to the size of the temperature difference when a temperature difference occurs between the junction and the open portion of two different materials.

[0005] The electromotive force that appears when infrared radiation energy is input is proportional to the temperature difference between the cold region and the hot region, so it is important to know how efficiently infrared energy is absorbed.

[0006] Therefore, it is important to design the sensor so that it can absorb as much energy as possible and not lose the energy once it has been absorbed.

[0007] Typically, a thermopile sensor forms multiple thermocouples on a substrate and forms an infrared absorbing layer on top of them.

[0008] Conventional thermopile sensors are manufactured in a circular shape with a two-dimensional planar structure and an infrared absorption pattern concentrated in the center, so the high temperature part (H) is concentrated in the center, making it difficult to measure uniform sensitivity at all locations.

[0009] The present invention aims to solve the above-mentioned needs and / or problems.

[0010] The present invention provides an infrared sensor with improved sensitivity.

[0011] The present invention provides a semiconductor gas sensor that ensures uniform sensitivity within all areas of the sensor.

[0012] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0013] In order to achieve the above object, an infrared sensor according to an embodiment of the present invention includes a substrate, a plurality of thermocouple modules disposed on one surface of the substrate, and electrodes disposed on one surface of the substrate, wherein the plurality of thermocouple modules include a first material, a second material, and an infrared absorbing layer disposed on the first material and the second material, wherein the first material and the second material include a high-temperature portion at an upper portion and a low-temperature portion at a lower portion, the infrared absorbing layer is disposed on the high-temperature portion at the upper portion of the first material and the second material, the electrodes include a first electrode disposed on the high-temperature portion at an upper portion of the thermocouple module and a second electrode formed on the low-temperature portion, and the first material and the second material include a hollow layer formed between the upper portion and the substrate.

[0014] Additionally, the plurality of thermocouple modules may be in the form of a taper.

[0015] Additionally, the first electrode may be disposed on the high-temperature portion of the upper portion of the first material and the second material, and the second electrode may be disposed on the low-temperature portion of the lower portion of the second material.

[0016] Additionally, the infrared absorbing layer may be disposed while covering the first electrode.

[0017] In addition, the infrared absorbing layer may be positioned in a high temperature area on the upper portion of the first material and the second material, and the surface area of ​​the infrared absorbing layer may be arranged to be smaller than the surface area of ​​the upper portion of the first material and the second material.

[0018] Additionally, the first material and the second material of the thermocouple module may be arranged as a Bi2Te3-based solid solution alloy and a PbTe alloy.

[0019] Additionally, the electrode may include a material having a Seebeck coefficient of less than -2.0 μV / K.

[0020] Additionally, the infrared absorbing layer may include graphene.

[0021] Additionally, each row of the infrared modules may be electrically connected in a zig-zag shape by the electrodes on the substrate.

[0022] Additionally, each row of the infrared modules can be individually electrically connected and arranged on the substrate by the electrodes.

[0023] An infrared sensor according to the embodiment can provide high sensitivity by implementing more thermocouples in a small area.

[0024] In addition, it can provide a uniform deviation of sensitivity concentrated in the center in a conventional two-dimensional planar circular structure.

[0025] Additionally, the space underneath the thermocouple module is empty, minimizing heat dissipation.

[0026] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0027] FIG. 1 is a plan view of an infrared sensor according to one embodiment of the present invention.

[0028] Figure 2 is a plan view of an infrared sensor according to another embodiment of the present invention.

[0029] Figure 3 is an enlarged view of part A of Figure 1.

[0030] Figure 4 is a cross-sectional view of the BB' portion of Figure 3.

[0031] Figure 5 is a process flow diagram of an infrared sensor according to an embodiment of the present invention.

[0032] Figures 6a to 6l are flowcharts according to the process sequence of the infrared sensor of the present invention.

[0033] Figure 7 is a plan view of an infrared sensor according to another embodiment of the present invention.

[0034] Fig. 8 is a cross-sectional view of the CC' portion of Fig. 7.

[0035] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined solely by the scope of the claims.

[0036] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are illustrative and are not limited to the details depicted. Like reference numerals designate like elements throughout the specification. Furthermore, in describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to unnecessarily obscure the gist of the present invention.

[0037] In the specification, when "includes," "has," and "consists of" are used, other parts may be added unless "only" is used. When a component is expressed in the singular, it includes the plural unless there is a special explicit description.

[0038] When interpreting a component, it is interpreted as including the error range even if there is no separate explicit description.

[0039] When the positional relationship and interconnectedness between two components are described as ‘on’, ‘above’, ‘below’, ‘next to’, ‘connect, couple’, crossing, intersecting, etc., one or more other components may be interposed between the components unless there is a mention of ‘directly’ or ‘directly’.

[0040] When the temporal relationship is explained with phrases such as ‘after’, ‘following’, ‘next to’, or ‘before’, it may not be continuous on the time axis unless ‘right away’ or ‘directly’ is used.

[0041] In the description of the embodiments, terms such as "first" and "second" are used to describe various components, but these components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, a "first" component referred to below may also be a "second" component within the technical scope of the present invention.

[0042] Identical reference numerals throughout the specification refer to identical components.

[0043] The features of the various embodiments may be partially or wholly combined or combined with each other, and various technical connections and operations are possible, and each embodiment may be implemented independently of each other or may be implemented together in a related relationship.

[0044] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0045] FIG. 1 is a plan view of an infrared sensor according to one embodiment of the present invention, FIG. 3 is an enlarged view of part A of FIG. 1, and FIG. 4 is a cross-sectional view of part AA' of FIG. 3.

[0046] Referring to FIG. 1, an infrared sensor (10) according to the present invention includes a substrate (100), a thermocouple module (200) disposed on the substrate (100), and an electrode (300) for electrically connecting each thermocouple module (200).

[0047] Each thermocouple module (200) is placed on a substrate (100) and the electrodes in each row can be connected in a zig-zag shape so as to be electrically connected to a common electrode (not shown).

[0048] When the rows of each thermocouple module (200) are connected in a zig-zag shape, the thermocouple modules (200) in odd rows and the thermocouple modules (200) in even rows can be arranged in a symmetrical structure.

[0049] To explain in detail, when the thermocouple modules and electrodes in odd rows are arranged in the order of electrode (300), first material (210), infrared absorbing layer (230), and second material (220) from the left, the thermocouple modules (200) in even rows may be arranged in the order of electrode (300), second material (220), infrared absorbing layer (230), and first material (210).

[0050] However, it is not necessarily limited to this, and can be modified in various ways as long as the thermocouple module (200) and the electrode are connected continuously.

[0051] For example, referring to FIG. 2, the thermocouple modules (200) of each row may be configured to be connected to electrodes by their respective common electrode connections (330). In this case, even if a defect such as a short circuit occurs in a row of individual thermocouple modules, there is no problem with the operation of other rows, which is advantageous in the reliability of the infrared module.

[0052] Referring to FIGS. 3 and 4, the thermocouple module (200) may include a first material (210), a second material (220), and an infrared absorbing layer (230).

[0053] In order to increase the temperature difference between the upper high-temperature part (H) where the infrared absorption layer (230) is placed and the lower low-temperature part (L) of the substrate (100), a cavity layer (400) may be placed between the first material (210) and the second material (220) and the substrate.

[0054] Even if a common layer (400) is placed inside each thermocouple module (200), each thermocouple module (200) may be placed in a tapered shape rather than being formed vertically so that sufficient support can be provided.

[0055] The infrared absorption layer (230) may be positioned at the center of the upper portion of the first material (210) and the second material (220). The surface area of ​​the infrared absorption layer (230) may be formed to be smaller than the high temperature portion (H) of the upper portion of each of the first material (210) and the second material (220).

[0056] Unlike the conventional two-dimensional thermocouple module (200) of an infrared sensor in which a high temperature section (H) is placed in the center and a low temperature section (L) is placed on the outside, the three-dimensional thermocouple module (200) of the present invention has a high temperature section (H) placed at the top where the infrared absorption layer (230) is placed, and a low temperature section (L) placed at the bottom. Therefore, it is necessary to increase the temperature difference between the upper and lower parts of each thermocouple module. Accordingly, a hollow layer (400) for lowering thermal conductivity can be placed at the bottom of the first material (210) and the second material (220).

[0057] An electromotive force is generated in proportion to the size of the temperature difference between the first electrode (310) positioned on the upper high temperature section (H) of the thermocouple module (200) and the second electrode (320) positioned on the second material layer at the lower portion of the thermocouple module (200). To this end, an infrared absorption layer (230) for efficiently absorbing infrared energy may be positioned on the first electrode (310) to cover the first electrode (310).

[0058] Since the high temperature of the upper high temperature part (H) is not transferred to the lower part by the common layer (400), the lower low temperature part (L) where the second electrode (320) is located is maintained, and an electromotive force is generated due to this temperature difference, allowing the infrared sensor (10) to operate.

[0059] FIG. 5 is a flowchart showing a method for manufacturing an infrared sensor according to one embodiment of the present invention, and FIGS. 6a to 6l are flowcharts according to the process sequence of the infrared sensor of the present invention.

[0060] First, a photoresist (PR) is patterned and placed on a substrate (100) (S501).

[0061] More specifically, referring to FIGS. 6A and 6B, a photoresist (PR) can be patterned and placed in a tapered shape on the upper portion of the substrate (100). The photoresist (PR) is placed in a tapered trapezoidal shape so that it can have sufficient support even when the cavity layer (400) is formed after the photoresist (PR) is removed later, and this will be described in detail later.

[0062] Afterwards, the first material (210) can be deposited and placed over the entire substrate (100) (S502).

[0063] The first material (210) is preferably disposed as a Bi2Te3-based solid solution alloy, but is not limited thereto. The first material (210) may also be disposed as a PbTe alloy. In addition, the first material (210) may also be disposed as another material having a high Seebeck coefficient and low electrical resistivity and thermal conductivity.

[0064] Next, a second material is placed (S503). More specifically, referring to FIGS. 6c to 6e, an additional photoresist (PR2) is patterned on top of the first material (210) placed on top of the patterned photoresist (PR), and then the first material (210) except for the first material (210) under the patterned photoresist (PR) is removed using an etching process or the like.

[0065] Afterwards, a second material (220) may be deposited and placed in the space where the first material (210) was etched, and the additional photoresist (PR2) may be removed. The first material (210) and the second material (220) may be placed with a slight gap between them. The second material (220) is preferably placed as a Bi2Te3-based solid solution alloy, but is not limited thereto. The second material (210) may also be placed as a PbTe alloy. In addition, the second material (210) may also be placed as another material having a large Seebeck coefficient and low electrical resistivity and thermal conductivity.

[0066] The following electrodes are placed (S504). More specifically, referring to FIGS. 6F to 6H, a photoresist (PR3) may be placed on the outer surface of the first and second materials (220) placed on top of the photoresist (PR) patterned in a tapered shape, and an electrode (300) may be placed.

[0067] Next, the photoresist (PR3) can be removed to form an electrode (300) formed as a first electrode (310) on the lower second material (220) and a second electrode (320) formed on the upper first material (210) and second material (220). The electrode (300) is positioned between a plurality of infrared absorbing layers (230) to electrically connect the infrared absorbing layers (230). Any commonly used metal can be used as the electrode, but it is preferable to select a material with a low Seebeck coefficient. Table 1 below shows the Seebeck coefficient of each metal.

[0068] Metal Seebeck coefficient (㎶ / K)Metal Seebeck coefficient (㎶ / K)Molybdenum (Mo) 10Graphite (C) 3.0Cadmium (Cd) 7.5Platinum (Pt) 0Tungsten (W) 7.5Sodium (Na) - 2.0Gold (Au) 6.5Potassium (K) - 9.0Silver (Ag) 6.5Nickel (Ni) - 15Copper (Cu) 6.5Constantan (constantan) - 35Aluminum (Al) 3.5Bismuth (Bi) - 72

[0069] Referring to the above [Table 1], it can be seen that molybdenum and gold have relatively high Seebeck coefficients, while sodium potassium nickel, constantan, etc. have low Seebeck coefficients. Since the Seebeck coefficient of graphene is generally about 20 to 40 μV / K, sodium potassium nickel, constantan, etc. with low Seebeck coefficients are suitable for the electrode pattern, but nickel is preferably selected when considering the manufacturing cost, etc. Next, an infrared absorbing layer (230) can be placed (S505). More specifically, referring to FIGS. 6i to 6k, an infrared absorbing layer (230) can be placed on a first electrode (310) placed on a thermocouple module (200). The infrared absorbing layer (230) may be composed of graphene oxide in the central portion of the upper portion where the first material (210) and the second material (220) are connected. Graphene oxide can be produced by oxidizing graphite with a strong oxidizing agent. In addition, in an embodiment of the present invention, the infrared absorption pattern can be arranged by stacking multiple graphene layers, adding a catalyst, or heat-treating a material partially including graphene to increase detection sensitivity. Next, the internal photoresist (PR) can be removed to arrange the cavity layer (400) (S506). More specifically, referring to FIG. 6l, the cavity layer (400) can be formed by removing the photoresist (PR) arranged under the first material (210) and the second material (220) of the thermocouple module (200).

[0070] In the case of the three-dimensional infrared sensor of the present invention, a high temperature section (H) and a low temperature section (L) are arranged for each thermocouple module (200), so that more detection layers can be formed in a small area, and naturally, an infrared sensor with improved sensitivity can be manufactured.

[0071] Figure 7 is a plan view of an infrared sensor according to another embodiment of the present invention.

[0072] Referring to Fig. 7, the high temperature section (H) and the low temperature section (L) of the thermocouple module for generating electromotive force can be formed alternately in the same row on the same plane. In this case, a large-area low temperature section (L) in which the electrode (300), the first material (210), and the second material (220) are partially overlapped and arranged, and a high temperature section (H) in which the first material (210) and the second material (220) are formed overlapping on the upper portion of the electrode (300) and an infrared absorbing layer (230) is additionally arranged over the upper portion can be arranged intersectingly.

[0073] Fig. 8 is a cross-sectional view of the CC' portion of Fig. 7.

[0074] Referring to Fig. 8, an insulating layer (510) and a planarization layer (520) for insulation and planarization may be placed on the upper portion of the substrate (100) using a chemical vapor deposition method (CVD). The insulating layer (510) may be formed of silicon oxide (SiO2, SiO X ) and, in the case of the planarization layer (520), it can be formed of silicon nitride (SiN).

[0075] In the case of the insulating layer (510) and the flattening layer (520), any inorganic material capable of insulation can be used, without limitation thereto.

[0076] Thereafter, a reinforcing layer (530) may be placed on the lower portion of the substrate (100) to enhance durability. The reinforcing layer (530) is preferably formed with a thickness of about 100 nm using a sputtering method and made of aluminum (Al), but is not limited thereto and may be used with any material capable of enhancing the durability of the etched substrate (100).

[0077] After forming a reinforcing layer (530) on the substrate (100), the reinforcing layer (530), the substrate (100), and the planarization layer (520) under the high-temperature section can be etched as a rear process.

[0078] The thermocouple module formed on the upper part of the insulating layer (510) can be arranged so that the low-temperature part (L) and the high-temperature part (H) intersect on the same plane.

[0079] First, the electrode (300) can be patterned and placed on a high temperature section (H) placed on top of an insulating layer (510) on which a substrate (10) is etched, and a low temperature section (L) placed spaced apart from the high temperature section (H).

[0080] A first material (210) and a second material (220) may be placed on the upper portion of the patterned electrode (300).

[0081] First, the first material (210) can be patterned and placed, and the second material (220) can be placed overlapping the portion where the first material (210) is not placed and the upper portion of the first material (210).

[0082] Afterwards, in the case of the low-temperature section (L), an electrode may be additionally placed on top of the first material (210) and the second material (220) placed on top of the patterned electrode (300). In the case of the high-temperature section (H), an infrared absorption layer (230) may be additionally placed on top of the electrode (300) to generate a temperature difference with the low-temperature section (L).

[0083] Since the content of the specification described in the problem to be solved, the means for solving the problem, and the effect described above does not specify the essential features of the claim, the scope of the claim is not limited by the matters described in the content of the specification.

[0084] While the embodiments of the present invention have been described in more detail with reference to the attached drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be implemented without departing from the technical spirit of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to illustrate, rather than limit, the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments.

[0085] Therefore, it should be understood that the embodiments described above are exemplary in all respects and not limiting.

Claims

1. Substrate; A plurality of thermocouple modules arranged on one surface of the above substrate; and Including an electrode arranged on one surface of the above substrate, The above plurality of thermocouple modules include a first material, a second material, and an infrared absorbing layer disposed on top of the first material and the second material, The above plurality of thermocouple modules include a high temperature section spaced apart from the substrate and a low temperature section arranged on the substrate, The above infrared absorbing layer is disposed on the high temperature section, The electrode includes a first electrode disposed on the high-temperature portion and a second electrode formed on the low-temperature portion, An infrared sensor comprising a hollow layer disposed between the high temperature section and the substrate.

2. Substrate; A plurality of thermocouple modules arranged on one surface of the above substrate; and Including an electrode arranged on one surface of the above substrate, The above-described plurality of thermocouple modules include a first material, a second material and an infrared absorbing layer, The above plurality of thermocouple modules include a low-temperature section formed by partially overlapping the electrodes and the first and second materials, and a high-temperature section formed with a smaller area than the low-temperature section and having an infrared absorbing layer disposed on the uppermost part of the overlapping section of the electrodes and the first and second materials. An infrared sensor in which the high temperature section and the low temperature section are arranged intersectingly on the same plane.

3. In paragraph 1, The above multiple thermocouple modules are infrared sensors in the form of a taper.

4. In paragraph 1, An infrared sensor in which the infrared absorbing layer is arranged to cover the first electrode.

5. In paragraph 4, An infrared sensor in which the surface area of ​​the infrared absorbing layer is arranged to be smaller than the surface areas of the upper portions of the first material and the second material.

6. In paragraph 1 or 2, The first and second materials of the above thermocouple module are Bi 2 Te 3 Infrared sensor arranged with a PbTe alloy and a PbTe alloy.

7. In paragraph 1 or 2, The above electrode is an infrared sensor containing a material having a Seebeck coefficient smaller than -2.0㎶ / K.

8. In paragraph 1 or 2, An infrared sensor wherein the infrared absorbing layer comprises graphene.

9. In paragraph 1 or 2, An infrared sensor in which each row of the above infrared modules is arranged in a zig-zag shape on the substrate by the electrodes.

10. In paragraph 1 or 2, An infrared sensor in which each row of the above infrared modules is individually connected and arranged on the substrate by the above electrodes.

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