Infrared thermopile sensor and method for manufacturing infrared thermopile sensor

Abstract

The application provides an infrared thermoelectric sensor and a preparation method of the infrared thermoelectric sensor, and the infrared thermoelectric sensor comprises a substrate including a first area and a second area located at the periphery of the first area, a device layer located on the substrate, the device layer comprising an interlayer insulation layer and a plurality of thermoelectric structure located in the interlayer insulation layer, the projection of the hot end of the thermoelectric structure to the substrate is located in the first area, the projection of the cold end of the thermoelectric structure to the substrate is located in the second area, an infrared absorption layer is located on the device layer, the projection of the infrared absorption layer to the device layer overlaps with the hot end of the thermoelectric structure, a lens support layer is located on the surface of the device layer and the surface of the infrared absorption layer, a focusing super-structured lens structure is located on the surface of the lens support layer on the first area and at least part of the second area, and the focusing super-structured lens structure is used for focusing incident infrared radiation to the infrared absorption layer. Therefore, the measurement accuracy of the infrared thermoelectric sensor is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an infrared thermopile sensor and a method for fabricating the infrared thermopile sensor. Background Technology

[0002] An infrared thermopile sensor is a non-contact thermoelectric conversion device based on the Seebeck effect, used to convert the infrared energy radiated by a target object into a measurable electrical signal. Infrared thermopile sensors are widely used in wearable devices, microelectronic devices, and other scenarios with weak heat sources.

[0003] Traditional infrared thermopile sensors typically use polycrystalline silicon as the thermoelectric material for the thermopile structure, and an infrared absorption layer is fabricated above the hot end of the thermopile structure to maximize the temperature of the hot end. However, the infrared flux of the infrared absorption layer is low and dispersed, and the area of ​​the infrared absorption layer is extremely limited by the device size. This results in a low absorption rate of the infrared absorption layer for incident infrared radiation, and the cold end of the thermopile structure also experiences a temperature rise due to infrared radiation. Consequently, the temperature difference between the hot and cold ends is poorly established, leading to low measurement accuracy of the infrared thermopile sensor. Summary of the Invention

[0004] This invention provides an infrared thermopile sensor and a method for fabricating the infrared thermopile sensor. By using a focusing metalens structure to focus infrared radiation onto the infrared absorption layer, the infrared flux of the infrared absorption layer is increased, thereby improving the measurement accuracy of the infrared thermopile sensor.

[0005] According to a first aspect of the present invention, an infrared thermopile sensor is provided, comprising: The substrate includes a first region and a second region located around the first region; A device layer is located on the substrate. The device layer includes an interlayer insulating layer and a plurality of thermopile structures located within the interlayer insulating layer. The projection of the hot end of the thermopile structure onto the substrate is located in a first region, and the projection of the cold end of the thermopile structure onto the substrate is located in a second region. An infrared absorption layer is located on the device layer, and the projection of the infrared absorption layer onto the device layer overlaps with the hot end of the thermopile structure. A lens support layer is located on the surface of the device layer and the surface of the infrared absorption layer; A focusing meta-lens structure is located on the surface of a lens support layer on the first region and at least part of the second region, the focusing meta-lens structure being used to focus incident infrared radiation onto the infrared absorption layer.

[0006] Optionally, the focusing metalens structure includes an array of several nanopillar structures.

[0007] Optionally, the size of the nanopillar structure gradually increases along the direction from the first region to the second region.

[0008] Optionally, the lens support layer includes: A light-transmitting dielectric layer is located on the surface of the device layer and the surface of the infrared absorption layer; An etching stop layer is located on the surface of the light-transmitting medium layer.

[0009] Optionally, the material of the light-transmitting dielectric layer is silicon dioxide; the material of the etching stop layer is silicon nitride.

[0010] Optionally, the substrate has a through cavity that penetrates the substrate of the first region and a portion of the second region.

[0011] Optionally, it may also include: an insulating support layer, the insulating support layer comprising: A first insulating layer is located on the surface of the substrate; A first support layer is located on the surface of the first insulating layer; A second insulating layer is located on the surface of the first support layer, wherein the device layer is located on the surface of the second insulating layer.

[0012] Optionally, the thermopile structure includes: a thermocouple layer, a first metal part, and a second metal part, wherein the first metal part is located on the surface of the hot end, and the second metal part is located on the surface of the cold end.

[0013] Optionally, it may also include a protective layer located between the device layer and the infrared absorption layer.

[0014] According to a second aspect of the present invention, the present invention provides a method for fabricating an infrared thermopile sensor, for fabricating an infrared thermopile sensor as described above, comprising: A substrate is provided, the substrate comprising a first region and a second region located at the periphery of the first region; A device layer is formed on the substrate. The device layer includes an interlayer insulating layer and a plurality of thermopile structures located within the interlayer insulating layer. The projection of the hot end of the thermopile structure onto the substrate is located in a first region, and the projection of the cold end of the thermopile structure onto the substrate is located in a second region. An infrared absorption layer is formed on the surface of the device layer, and the projection of the infrared absorption layer onto the device layer overlaps with the hot end of the thermopile structure. A lens support layer is formed on the surface of the device layer and the surface of the infrared absorption layer; A focusing meta-lens structure is formed on the surface of the lens support layer in the first region and at least a portion of the second region, the focusing meta-lens structure being used to focus incident infrared radiation onto the infrared absorption layer.

[0015] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects: In the infrared thermopile sensor and its fabrication method provided by the present invention, the substrate includes a first region and a second region located around the first region. The device layer is located on the substrate and includes an interlayer insulating layer and a plurality of thermopile structures located within the interlayer insulating layer. The projection of the hot end of the thermopile structure onto the substrate is located in the first region, and the projection of the cold end of the thermopile structure onto the substrate is located in the second region. An infrared absorption layer is located on the device layer, and the projection of the infrared absorption layer onto the device layer overlaps with the hot end of the thermopile structure. A lens support layer is located on the surface of the device layer and the surface of the infrared absorption layer. A focusing metalens structure is located on the first region and on the surface of the lens support layer in at least part of the second region. The focusing metalens structure is used to focus incident infrared radiation onto the infrared absorption layer, so that the incident infrared radiation passes through the focusing metalens structure into the lens support layer and is focused on the infrared absorption layer. Therefore, by integrating a focusing metalens structure onto a traditional thermopile sensor, incident infrared radiation is focused onto the infrared absorption layer, increasing the infrared radiation flux per unit area of ​​the infrared absorption layer and raising the temperature of the hot end of the thermopile structure in the first region. At the same time, it avoids the cold end of the infrared thermopile structure in the second region from receiving infrared radiation and heating up, thereby improving the measurement accuracy of the infrared thermopile sensor. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figures 1-13 This is a schematic diagram of the structure corresponding to each step in the fabrication method of the infrared thermopile sensor according to an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 100-substrate; I-First District; II - Second Zone; 200 - Insulation support layer; 210 - First insulating layer; 220 - First support layer; 230 - Second insulating layer; 300 - Device layer; 310-Thermopile structure; 400 - Protective layer; 311 - Thermocouple layer; 3111 - First thermocouple layer; 3112 - Second thermocouple layer; 3121 - First Metal Section; 3122 - Second metal part; 320 - Interlayer insulation layer; 321 - First interlayer insulation layer; 322 - Second interlayer insulation layer; 500-Infrared Absorption Layer; 600 - Lens support layer; 610 - Transparent dielectric layer; 620 - Etching stop layer; 710 - Initial lens layer; 700-focusing meta-lens structure; 110 - Cavity. Detailed Implementation

[0019] As mentioned in the background section, the present invention aims to solve the technical problem of measurement accuracy of infrared thermopile sensors in the prior art.

[0020] In existing technologies, the method to improve the measurement accuracy of infrared thermopile sensors is to increase the area of ​​the infrared absorption layer. However, this approach has at least the following technical problems: (1) Increasing the area of ​​the infrared absorption layer will result in a larger overall size of the infrared thermopile sensor under the same measurement accuracy requirements, which cannot meet the miniaturization requirements of wearable devices, microelectronic devices, etc.

[0021] (2) After the area of ​​the infrared absorption layer is increased, the infrared radiation is more dispersed on the surface of the infrared absorption layer. The infrared flux per unit area of ​​the infrared absorption layer is not increased. The local temperature rise at the hot end of the thermopile structure is limited, and the temperature difference between the hot and cold ends is difficult to be effectively amplified. The improvement in measurement accuracy is not obvious.

[0022] (3) After the area of ​​the infrared absorption layer increases, the heat capacity of the infrared absorption layer increases, the heating rate of the hot end of the thermopile structure slows down, and the response speed of the infrared thermopile sensor decreases.

[0023] In view of this, the present invention proposes an infrared thermopile sensor, comprising a substrate including a first region and a second region located around the first region; a device layer on the substrate, the device layer including an interlayer insulating layer and a plurality of thermopile structures located within the interlayer insulating layer, wherein the projection of the hot end of the thermopile structure onto the substrate is located in the first region, and the projection of the cold end of the thermopile structure onto the substrate is located in the second region; an infrared absorption layer is located on the device layer, the projection of the infrared absorption layer onto the device layer overlapping the hot end of the thermopile structure; a lens support layer is located on the surface of the device layer and the surface of the infrared absorption layer; a focusing metalens structure is located on the first region and at least part of the lens support layer surface on the second region, the focusing metalens structure being used to focus incident infrared radiation onto the infrared absorption layer. Thus, by integrating a focusing metalens structure onto a conventional thermopile sensor, incident infrared radiation is focused onto the infrared absorption layer, increasing the infrared radiation flux per unit area of ​​the infrared absorption layer, increasing the temperature of the hot end of the thermopile structure in the first region, and simultaneously preventing the cold end of the infrared thermopile structure in the second region from receiving infrared radiation and heating up, thereby improving the measurement accuracy of the infrared thermopile sensor.

[0024] Furthermore, since the infrared radiation flux per unit area of ​​the infrared absorption layer is increased, the area of ​​the infrared absorption layer can be reduced while maintaining the same measurement accuracy of the infrared thermopile sensor, thereby reducing the area of ​​the infrared thermopile sensor.

[0025] Furthermore, while maintaining the same measurement accuracy for infrared thermopile sensors, reducing the area of ​​the infrared absorption layer decreases its heat capacity, thereby improving the response speed of the infrared absorption layer.

[0026] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0028] Figures 1-13This is a schematic diagram of the structure corresponding to each step in the fabrication method of the infrared thermopile sensor according to an embodiment of the present invention.

[0029] Please refer to Figure 1 A substrate 100 is provided, which may include a first region I and a second region II located around the first region I.

[0030] In this embodiment, the substrate 100 can be made of silicon. As an example, the substrate 100 may also include at least one of the following materials: Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP, InGaAs, or other III / V compound semiconductors. The size of the substrate 100 may be, for example, 6 inches, 8 inches, or 12 inches, and the present invention does not limit this.

[0031] Please refer to Figure 2 An insulating support layer 200 is formed on the surface of the substrate 100.

[0032] In one embodiment, forming an insulating support layer 200 on the surface of the substrate 100 may include: Please refer to Figure 2 A first insulating layer 210 is formed on the surface of the substrate 100.

[0033] In this embodiment, the material of the first insulating layer 210 can be silicon dioxide.

[0034] Please continue to refer to this. Figure 2 A first support layer 220 is formed on the surface of the first insulating layer 210.

[0035] In this embodiment, the material of the first support layer 220 can be silicon nitride.

[0036] Please continue to refer to this. Figure 2 A second insulating layer 230 is formed on the surface of the first support layer 220.

[0037] In this embodiment, the material of the second insulating layer 230 can be silicon dioxide.

[0038] In another example, forming an insulating support layer 200 on the surface of the substrate 100 may also include: first forming an insulating layer on the surface of the substrate 100; and then forming a support layer on the insulating layer. This invention is not limited thereto.

[0039] Please refer to Figures 3-8 A device layer 300 is formed on a substrate 100. The device layer 300 may include an interlayer insulating layer 320 and a plurality of thermopile structures 310 located within the interlayer insulating layer 320. The projection of the hot end of the thermopile structure 310 onto the substrate 100 is located in a first region I, and the projection of the cold end of the thermopile structure 310 onto the substrate 100 is located in a second region II.

[0040] In one embodiment, please continue to refer to Figures 3-7 Each thermopile structure 310 may include: a thermocouple layer 311, a first metal part 3121 and a second metal part 3122, an interlayer insulating layer 320 located on the surface of the thermocouple layer 311 and the substrate 100, the first metal part 3121 located on the surface of the hot end, and the second metal part 3122 located on the surface of the cold end.

[0041] In one example, the thermocouple layer 311 can be a single-layer structure.

[0042] In another example, the thermocouple layer 311 can also be a multilayer thermocouple structure. This structure may include a first thermocouple layer 3111 and a second thermocouple layer 3112, with opposite conductivity types. When the thermocouple layer 311 is a multilayer thermocouple structure, the corresponding interlayer insulation layer 320 can also be a multilayer interlayer insulation layer structure. This structure includes a first interlayer insulation layer 321 and a second interlayer insulation layer 322. The first interlayer insulation layer 321 is located on the surface of the first thermocouple layer 3111 and the surface of the insulating support layer 200, while the second interlayer insulation layer 322 is located on the surface of the second thermocouple layer 3112 and the surface of the first interlayer insulation layer 321.

[0043] In this embodiment, the thermocouple layer 311 can be made of polycrystalline silicon.

[0044] In this embodiment, the material of the interlayer insulating layer 320 can be silicon dioxide.

[0045] In one specific embodiment, the method of forming a device layer 300 on a substrate 100 may include: Please refer to Figure 3 A plurality of first thermocouple layers 3111 are formed on the surface of a partial insulating support layer 200, each first thermocouple layer 3111 being located on a first region I and a second region II.

[0046] Specifically, each first thermocouple layer 3111 is located on the surface of the insulating support layer 200 on the second region II and extends to a portion of the surface of the insulating support layer 200 on the first region I. Each first thermocouple layer 3111 spans the interface between the first region I and the second region II.

[0047] Please refer to Figure 4 A first interlayer insulation layer 321 is formed on the surface of several first thermocouple layers 3111 and the surface of the insulating support layer 200.

[0048] Please refer to Figure 5A corresponding second thermocouple layer 3112 is formed on the surface of the first interlayer insulation layer 321 on each first thermocouple layer 3111, and each second thermocouple layer 3112 is located on the first region I and the second region II.

[0049] In this embodiment, the projection of the second thermocouple layer 3112 onto the substrate is located within the projection range of the corresponding first thermocouple layer 3111 onto the substrate.

[0050] Please refer to Figure 6 A second interlayer insulation layer 322 is formed on the surface of several second thermocouple layers 3112 and on the surface of the first interlayer insulation layer 321.

[0051] Please refer to Figure 7 A first metal portion 3121 is formed on the surface of each first thermocouple layer 3111 in the first region I and on the surface of each second thermocouple layer 3112 in the first region I, and a second metal portion 3122 is formed on the surface of each first thermocouple layer 3111 in the second region II and on the surface of each second thermocouple layer 3112 in the second region II. Both the first metal portion 3121 and the second metal portion 3122 are located within the interlayer insulation layer 320.

[0052] Specifically, the first metal portion 3121 on the first region I penetrates the interlayer insulation layer 320, and the second metal portion 3122 on the surface of the first thermocouple layer 3111 on the second region II is connected to the second metal portion 3122 on the surface of the second thermocouple layer 3112 through the metal layer.

[0053] Please refer to Figure 8 A protective layer 400 is formed on the surface of the second interlayer insulating layer 322 and the surface of the second metal part 3122.

[0054] As an example, the material of the protective layer 400 can be silicon nitride.

[0055] Please refer to Figure 9 An infrared absorption layer 500 is formed on the surface of the device layer 300. The projection of the infrared absorption layer 500 onto the device layer 300 overlaps with the hot end of the thermopile structure 310. That is, the projection of the infrared absorption layer 500 onto the substrate is located within the substrate of the first region I.

[0056] In this embodiment, an infrared absorption layer 500 is formed on the surface of the device layer 300, which may specifically include: forming an infrared absorption layer 500 on the surface of the protective layer 400 on the first region I.

[0057] In this embodiment, the material of the infrared absorption layer 500 can be, for example, silicon nitride. Of course, the present invention is not limited to this, and the infrared absorption layer 500 can also be, for example, titanium and platinum, materials with strong infrared radiation absorption capabilities.

[0058] Please refer to Figure 10 A lens support layer 600 is formed on the surface of the device layer 300 and the surface of the infrared absorption layer 500.

[0059] In one embodiment, forming a lens support layer 600 on the surface of the device layer 300 and the surface of the infrared absorption layer 500 may include: Please continue to refer to this. Figure 10 A light-transmitting dielectric layer 610 is formed on the surface of the device layer 300 and the surface of the infrared absorption layer 500.

[0060] In this embodiment, the material of the light-transmitting medium layer 610 can be silicon dioxide. Of course, it should be understood that the present invention is not limited thereto, and the material of the light-transmitting medium layer 610 can also be a material with high light transmittance, such as alumina.

[0061] In this embodiment, the thickness of the light-transmitting medium layer 610 is set based on the focal length of the subsequently formed focusing meta-lens structure. Specifically, the thickness of the light-transmitting medium layer 610 is the focal length of the focusing meta-lens structure ±0.5μm.

[0062] Please continue to refer to this. Figure 10 An etching stop layer 620 is formed on the surface of the light-transmitting medium layer 610.

[0063] In this embodiment, the material of the etch stop layer 620 can be silicon nitride.

[0064] Please refer to Figures 11-12 A focusing metalens structure 700 is formed on the surface of the lens support layer in the first region I and at least part of the second region II. The focusing metalens structure 700 is used to focus incident infrared radiation onto the infrared absorption layer 500.

[0065] In this embodiment, the incident infrared radiation passes through the focusing meta-lens structure 700 and the lens support layer 600, and is focused in the infrared absorption layer 500.

[0066] In this embodiment, a focusing metalens structure 700 is formed on the lens support layer surface in the first region I and at least a portion of the second region II, which may include: Please refer to Figure 11 An initial lens layer 710 is formed on the surface of the lens support layer 600 on the first region I and at least part of the second region II.

[0067] Please refer to Figure 12 The initial lens layer 710 is etched to form a focusing metalens structure 700.

[0068] In this embodiment, the focusing metalens structure 700 may include an array composed of several nanopillar structures.

[0069] As a specific embodiment, the size of the nanocolumnar structure gradually increases along the direction from the first region I to the second region II.

[0070] In this embodiment, the material of the focusing metalens structure 700 can be silicon.

[0071] Silicon exhibits excellent transmittance in the 1μm-8μm wavelength range, and focusing metalenses made of silicon can achieve focusing efficiencies of up to 88%~92%. Furthermore, silicon materials are highly compatible with existing infrared thermopile sensor fabrication processes.

[0072] In this embodiment, an array of nanopillar structures is used as the focusing metalens structure 700. This allows incident infrared radiation to be focused onto the infrared absorption layer 500 through the focusing metalens structure 700, thereby improving the absorption of incident infrared radiation by the infrared thermopile sensor. Furthermore, by forming an array of nanopillar structures, the absorption of incident infrared radiation can be adjusted by modifying the size and spacing of the nanopillar structures, thus improving the accuracy of controlling the phase of infrared radiation. Additionally, the array of nanopillar structures can also refract the incident infrared radiation, focusing it onto the infrared absorption layer 500 after refraction, further enhancing the absorption of incident infrared radiation by the infrared absorption layer 500.

[0073] Please refer to Figure 13 A cavity 110 is formed in the substrate 100 under the first region I, penetrating the substrate 100.

[0074] In the above embodiments, by integrating a focusing metalens structure 700 onto a conventional thermopile sensor, incident infrared radiation is focused onto the infrared absorption layer 500, increasing the infrared radiation flux per unit area of ​​the infrared absorption layer 500, thereby increasing the temperature of the hot end of the thermopile structure 310 in the first region I. At the same time, it prevents the cold end of the infrared thermopile structure 310 in the second region II from receiving infrared radiation and heating up, thus improving the measurement accuracy of the infrared thermopile sensor.

[0075] Furthermore, in this embodiment, since the infrared radiation flux per unit area of ​​the infrared absorption layer 500 is increased, the area of ​​the infrared absorption layer 500 can be reduced while maintaining the same measurement accuracy of the infrared thermopile sensor, thereby reducing the area of ​​the infrared thermopile sensor.

[0076] Specifically, in this embodiment, the infrared radiation flux per unit area of ​​the infrared absorption layer 500 is more than double that of the infrared absorption layer 500 in a conventional infrared thermopile sensor. Therefore, while maintaining the same measurement accuracy, the area of ​​the infrared absorption layer 500 can be reduced by more than half.

[0077] Furthermore, in this embodiment, while maintaining the same measurement accuracy of the infrared thermopile sensor, the area of ​​the infrared absorption layer 500 is reduced, which can reduce the heat capacity of the infrared absorption layer 500 and thereby improve the response speed of the infrared absorption layer 500.

[0078] Accordingly, please refer to Figures 1-13 The present invention also provides an infrared thermopile sensor formed by the above-described method for preparing an infrared thermopile sensor, which may include: a substrate 100, a device layer 300, an infrared absorption layer 500, a lens support layer 600, and a focusing metalens structure 700.

[0079] Device layer 300 is located on substrate 100. Device layer 300 includes interlayer insulating layer 320 and a plurality of thermopile structures 310 located within interlayer insulating layer 320. The projection of the hot end of thermopile structure 310 onto substrate 100 is located in first region I, and the projection of the cold end of thermopile structure 310 onto substrate 100 is located in second region II.

[0080] The infrared absorption layer 500 is located on the device layer 300, and the projection of the infrared absorption layer 500 onto the device layer 300 overlaps with the hot end of the thermopile structure.

[0081] The lens support layer 600 is located on the surface of the device layer 300 and the surface of the infrared absorption layer 500.

[0082] The focusing meta-lens structure 700 is located on the surface of the lens support layer 600 on the first region I and at least part of the second region II. The focusing meta-lens structure 700 is used to focus incident infrared radiation onto the infrared absorption layer 500.

[0083] In this embodiment, the incident infrared radiation passes through the focusing meta-lens structure 700 and the lens support layer 600, and is focused in the infrared absorption layer 500.

[0084] In one embodiment, the material of the focusing metalens structure 700 is silicon.

[0085] Silicon exhibits excellent transmittance in the 1μm-8μm wavelength range, and the focusing efficiency of a silicon-based meta-lens structure 700 can reach 88%~92%. Furthermore, silicon materials are highly compatible with existing infrared thermopile sensor fabrication processes.

[0086] In this embodiment, the focusing metalens structure 700 may include an array composed of several nanopillar structures.

[0087] In this embodiment, using an array of several nano-pillar structures as the focusing metalens structure 700 can improve the accuracy of controlling the infrared radiation phase.

[0088] As a specific embodiment, the size of the nanocolumnar structure gradually increases along the direction from the first region I to the second region II.

[0089] In this embodiment, the material of the infrared absorption layer 500 can be, for example, silicon nitride. Of course, the present invention is not limited to this. The infrared absorption layer 500 can also be, for example, titanium and platinum, materials with strong infrared radiation absorption capabilities, so as to maximize the absorption rate of infrared light.

[0090] As can be seen, by integrating a focusing metalens structure 700 onto a conventional thermopile sensor, the present invention focuses incident infrared radiation onto the infrared absorption layer 500, increases the infrared radiation flux per unit area of ​​the infrared absorption layer 500, and increases the temperature of the hot end of the thermopile structure 310 in the first region I. At the same time, it avoids the cold end of the infrared thermopile structure 310 in the second region II from receiving infrared radiation and heating up, thereby improving the measurement accuracy of the infrared thermopile sensor.

[0091] Furthermore, in this embodiment, since the infrared radiation flux per unit area of ​​the infrared absorption layer 500 is increased, the area of ​​the infrared absorption layer 500 can be reduced while maintaining the same measurement accuracy of the infrared thermopile sensor, thereby reducing the area of ​​the infrared thermopile sensor.

[0092] Specifically, in this embodiment, the infrared radiation flux per unit area of ​​the infrared absorption layer 500 is more than double that of the infrared absorption layer 500 in a conventional infrared thermopile sensor. Therefore, while maintaining the same measurement accuracy, the area of ​​the infrared absorption layer 500 can be reduced by more than half.

[0093] Furthermore, in this embodiment, while maintaining the same measurement accuracy of the infrared thermopile sensor, the area of ​​the infrared absorption layer 500 is reduced, which can reduce the heat capacity of the infrared absorption layer 500 and thereby improve the response speed of the infrared absorption layer 500.

[0094] In one specific embodiment, please continue to refer to Figure 13 The lens support layer includes a light-transmitting dielectric layer 610 and an etching stop layer 620.

[0095] The light-transmitting dielectric layer 610 is located on the surface of the device layer 300 and the surface of the infrared absorption layer 500.

[0096] The etching stop layer 620 is located on the surface of the light-transmitting dielectric layer 610.

[0097] In one specific embodiment, the material of the light-transmitting dielectric layer 610 can be silicon dioxide; the material of the etch stop layer 620 can be silicon nitride.

[0098] In this embodiment, the material of the light-transmitting medium layer 610 can also be a material with high light transmittance, such as alumina.

[0099] In this embodiment, the thickness of the light-transmitting medium layer 610 is set based on the focal length of the subsequently formed focusing meta-lens structure 700. Specifically, the thickness of the light-transmitting medium layer 610 is the focal length of the focusing meta-lens structure 700 ± 0.5 μm.

[0100] In one embodiment, the infrared thermopile sensor may further include an insulating support layer 200, which may include a first insulating layer 210, a first support layer 220, and a second insulating layer 230.

[0101] The first insulating layer 210 is located on the surface of the substrate 100.

[0102] The first support layer 220 is located on the surface of the first insulating layer 210.

[0103] The second insulating layer 230 is located on the surface of the first support layer 220, wherein the device layer 300 is located on the surface of the second insulating layer 230.

[0104] In this embodiment, the first insulating layer 210 can be made of silicon dioxide. The first support layer 220 can be made of silicon nitride. The second insulating layer 230 can be made of silicon dioxide.

[0105] In another example, the insulating support layer 200 may also include an insulating layer and a support layer located on the insulating layer. The invention is not limited thereto.

[0106] In one embodiment, each thermopile structure 310 may include: a thermocouple layer 311, a first metal portion 3121 and a second metal portion 3122, with an interlayer insulating layer 320 located on the surface of the thermocouple layer 311 and the substrate 100, the first metal portion 3121 located on the surface of the hot end and the second metal portion 3122 located on the surface of the cold end.

[0107] In one example, the thermocouple layer 311 can be a single-layer structure.

[0108] In another example, the thermocouple layer 311 can also be a multilayer thermocouple structure. This structure may include a first thermocouple layer 3111 and a second thermocouple layer 3112, with opposite conductivity types. When the thermocouple layer 311 is a multilayer thermocouple structure, the corresponding interlayer insulation layer 320 can also be a multilayer interlayer insulation layer structure. This structure includes a first interlayer insulation layer 321 and a second interlayer insulation layer 322. The first interlayer insulation layer 321 is located on the surface of the first thermocouple layer 3111 and the surface of the insulating support layer 200, while the second interlayer insulation layer 322 is located on the surface of the second thermocouple layer 3112 and the surface of the first interlayer insulation layer 321.

[0109] In this embodiment, the thermocouple layer 311 can be made of polycrystalline silicon.

[0110] In this embodiment, the material of the interlayer insulating layer 320 can be silicon dioxide.

[0111] In one specific embodiment, the infrared thermopile sensor may further include a protective layer 400, which is located between the device layer 300 and the infrared absorption layer 500.

[0112] As an example, the material of the protective layer 400 can be silicon nitride.

[0113] In one implementation, please refer to [link / reference needed]. Figure 13 The substrate 100 has a through cavity 110 that penetrates the first region I and part of the second region II of the substrate 100.

[0114] Since the infrared thermopile sensor in this embodiment corresponds to the fabrication method of the infrared thermopile sensor described above, please refer to the detailed explanation of the corresponding part in the fabrication method of the infrared thermopile sensor described above for the explanation of each feature structure in the infrared thermopile sensor in this embodiment, and it will not be repeated here.

[0115] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An infrared thermopile sensor, characterized in that, include: The substrate includes a first region and a second region located around the first region; A device layer is located on the substrate. The device layer includes an interlayer insulating layer and a plurality of thermopile structures located within the interlayer insulating layer. The projection of the hot end of the thermopile structure onto the substrate is located in a first region, and the projection of the cold end of the thermopile structure onto the substrate is located in a second region. An infrared absorption layer is located on the device layer, and the projection of the infrared absorption layer onto the device layer overlaps with the hot end of the thermopile structure. A lens support layer is located on the surface of the device layer and the surface of the infrared absorption layer; A focusing meta-lens structure is located on the surface of a lens support layer on the first region and at least part of the second region, the focusing meta-lens structure being used to focus incident infrared radiation onto the infrared absorption layer.

2. The infrared thermopile sensor as described in claim 1, characterized in that, The focusing metalens structure comprises an array of several nanopillar structures.

3. The infrared thermopile sensor as described in claim 2, characterized in that, The size of the nanopillar structure gradually increases along the direction from the first region to the second region.

4. The infrared thermopile sensor as described in claim 1, characterized in that, The lens support layer includes: A light-transmitting dielectric layer is located on the surface of the device layer and the surface of the infrared absorption layer; An etching stop layer is located on the surface of the light-transmitting medium layer.

5. The infrared thermopile sensor as described in claim 4, characterized in that, The material of the light-transmitting medium layer is silicon dioxide; the material of the etching stop layer is silicon nitride.

6. The infrared thermopile sensor as described in claim 1, characterized in that, The substrate has a through cavity that penetrates the substrate of the first region and a portion of the second region.

7. The infrared thermopile sensor as described in claim 1, characterized in that, Also includes: An insulating support layer, the insulating support layer comprising: A first insulating layer is located on the surface of the substrate; A first support layer is located on the surface of the first insulating layer; A second insulating layer is located on the surface of the first support layer, wherein the device layer is located on the surface of the second insulating layer.

8. The infrared thermopile sensor as described in claim 1, characterized in that, The thermopile structure includes: a thermocouple layer, a first metal part, and a second metal part, wherein the first metal part is located on the surface of the hot end, and the second metal part is located on the surface of the cold end.

9. The infrared thermopile sensor as described in claim 1, characterized in that, Also includes: A protective layer is located between the device layer and the infrared absorption layer.

10. A method for fabricating an infrared thermopile sensor, characterized in that, include: A substrate is provided, the substrate comprising a first region and a second region located at the periphery of the first region; A device layer is formed on the substrate. The device layer includes an interlayer insulating layer and a plurality of thermopile structures located within the interlayer insulating layer. The projection of the hot end of the thermopile structure onto the substrate is located in a first region, and the projection of the cold end of the thermopile structure onto the substrate is located in a second region. An infrared absorption layer is formed on the surface of the device layer, and the projection of the infrared absorption layer onto the device layer overlaps with the hot end of the thermopile structure. A lens support layer is formed on the surface of the device layer and the surface of the infrared absorption layer; A focusing meta-lens structure is formed on the surface of the lens support layer in the first region and at least a portion of the second region, the focusing meta-lens structure being used to focus incident infrared radiation onto the infrared absorption layer.

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