Thermopile infrared sensor and method of manufacturing the same

Abstract

The present application relates to a kind of thermoelectric infrared sensor and its manufacturing method, wherein, thermoelectric infrared sensor includes: the bearing substrate provided with film-like thermistor, bearing substrate includes opposite first surface and second surface;Thermoelectric structure, thermoelectric structure includes the first substrate provided with first cavity and the thermoelectric body of setting on the first substrate, and the thermoelectric body is at least by a group of thermocouple pair constitutes, and the first substrate is set on the first surface of bearing substrate.The present application is by thermistor being arranged on bearing substrate, so that thermoelectric structure and thermistor can be formed in the same package structure simultaneously, realizes integrated package, shorten process step, reduce the volume of infrared thermoelectric sensor, improve the reliability of infrared thermoelectric sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor device manufacturing, and in particular to a thermoelectric infrared sensor and a manufacturing method thereof. BACKGROUND

[0002] With the development of the Internet of Things technology and the improvement of people's quality of life, the application prospect of infrared detectors is becoming more and more extensive. Among them, the thermoelectric infrared sensor is one of the earliest researched and practical infrared imaging devices. As a non-cryogenic infrared detector, it has the advantages of small size, light weight, no need for cooling, high sensitivity, and is widely used in safety monitoring, medical treatment, life detection and consumer products, and its development is also more rapid.

[0003] The working principle of the thermoelectric pile is mainly based on the Seebeck effect, that is, through the series connection of two different materials or two objects with the same material but different work functions, when infrared radiation is irradiated on the center position of the chip, the center will be heated, so the hot junction temperature rises, and the cold junction does not change with the center. The temperature rise of the hot junction and the cold junction forms a temperature difference ΔT, thereby forming an output voltage, and the output voltage is processed to measure the temperature of the object.

[0004] Generally, the thermoelectric infrared sensor converts the infrared radiation energy of the human body into a continuous output voltage signal through the thermoelectric chip, and forms a voltage dividing signal in the circuit loop through the thermistor chip (NTC). The voltage signal and the voltage dividing signal are processed, and whether the thermoelectric chip and the thermistor chip have a temperature difference caused by infrared radiation is calculated according to the voltage signal and the voltage dividing signal, so as to determine whether there is a human body in the surrounding space, thereby avoiding the use of a flexible delay control chip and the estimation of the delay parameter in advance, and improving the accuracy and convenience of human body sensing.

[0005] However, the thermoelectric infrared sensor produced at present is formed by the thermoelectric chip and the thermistor respectively, and is mounted on the sub-encapsulation base, so that the process steps are long, the volume is large, and the reliability is long due to the external lead connection. SUMMARY

[0006] The purpose of the present application is to provide a thermoelectric infrared sensor and a manufacturing method thereof, which can be integrated and packaged, reduce the size, and improve the reliability and measurement accuracy.

[0007] In order to achieve the above purpose, the present application provides a thermoelectric infrared sensor, comprising:

[0008] A bearing substrate provided with a film-shaped thermistor, the bearing substrate comprising opposite first and second surfaces;

[0009] A thermoelectric structure includes a first substrate provided with a first cavity and a thermoelectric body disposed on the first substrate, the thermoelectric body being formed by at least one thermocouple pair, the first substrate being disposed on a first surface of the carrier substrate.

[0010] The application also provides a manufacturing method of the thermoelectric infrared sensor, comprising:

[0011] A carrier substrate is provided, which includes opposite first and second surfaces;

[0012] A thermistor is formed in the carrier substrate, on the first surface of the carrier substrate, or on the second surface of the carrier substrate;

[0013] A thermoelectric structure is formed and bonded to the first surface of the carrier substrate, the thermoelectric structure including a first substrate formed on the first surface of the carrier substrate, and a thermoelectric body formed on the first substrate, the first substrate being provided with a first cavity penetrating the first substrate, the thermoelectric body being formed by at least one thermocouple pair, and the thermoelectric body covering the first cavity.

[0014] The thermoelectric infrared sensor has the following advantages:

[0015] By disposing the thermistor on the carrier substrate, the thermoelectric structure and the thermistor can be formed in the same package structure, realizing integrated packaging, shortening the process steps, reducing the volume of the infrared thermoelectric sensor, and improving the reliability of the infrared thermoelectric sensor. In addition, the ambient temperature of the thermoelectric structure can be detected by the thermistor, and the temperature signal detected by the thermoelectric structure can be calculated to accurately measure the body temperature, avoid the temperature error caused by the influence of infrared radiation on the thermoelectric structure, and improve the detection accuracy.

[0016] Further, by disposing the thermistor on the first surface, the second surface, and the interior of the carrier substrate, the thermistor can detect the ambient temperature of the thermoelectric structure, further improving the accuracy and convenience of human sensing.

[0017] Further, by the first electrical connection structure, the thermoelectric structure is electrically connected to the outside, and by the setting of the thermistor and the external circuit, the thermoelectric structure and the thermistor can be electrically connected to the outside, avoiding the interference between the detection signals of the thermoelectric structure and the thermistor, and further avoiding measurement errors, thereby improving the measurement accuracy.

[0018] Further, by setting the top cover with an infrared filter layer, the infrared light is transmitted through the infrared filter layer, so that the thermoelectric structure can detect the temperature; by setting the annular connecting layer, the annular connecting layer, the top cover and the thermoelectric structure together form a closed cavity, so that the infrared light can be better transmitted to the thermoelectric structure, and other light can not interfere with the infrared light.

[0019] The manufacturing method of the thermoelectric infrared sensor has the following advantages:

[0020] By forming the bearing substrate with a thermistor, the thermoelectric structure and the thermistor are formed in the same packaging structure, realizing integrated packaging, shortening the process steps, reducing the volume of the infrared sensor, and the thermistor is formed on the bearing substrate, which can facilitate the detection of the ambient temperature of the thermoelectric structure, thereby avoiding the influence of the environment on the temperature measurement accuracy of the thermoelectric structure, and improving the reliability.

[0021] Further, different formation methods are used according to the formation position of the thermistor relative to the bearing substrate, so as to avoid damage to the thermistor during manufacturing, shorten the process steps, and improve the reliability of the infrared thermoelectric sensor.

[0022] Further, by forming an annular connecting layer on the thermoelectric structure and bonding a top cover, a sealed second cavity is formed by the top cover, the annular connecting layer and the thermoelectric structure, so that the infrared light can be better transmitted, and other light can not interfere with the infrared light to be detected, thereby affecting the measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor.

[0024] Figure 1 Fig. 1 shows a structure schematic diagram of a thermoelectric infrared sensor according to an embodiment of the present application;

[0025] Figure 2 Fig. 2 shows a structure schematic diagram of a thermoelectric infrared sensor according to another embodiment of the present application;

[0026] Figure 3 Fig. 3 shows a structure schematic diagram of a thermoelectric infrared sensor according to another embodiment of the present application;

[0027] Figures 4 to 14The manufacturing method of the thermoelectric infrared sensor of the embodiment 2 of the present application is shown in the structure schematic diagram corresponding to different steps.

[0028] Explanation of reference numerals:

[0029] 1, bearing substrate; 11, first surface; 12, second surface; 13, groove; 14, first substrate; 15, second substrate; 2, thermistor; 3, thermoelectric structure; 31, first substrate; 311, first cavity; 32, thermoelectric body; 33, isolation layer; 4, connecting bump; 5, first electrical connection structure; 6, first interconnection structure; 7, second interconnection structure; 8, annular connecting layer; 81, second cavity; 9, top cover. DETAILED DESCRIPTION

[0030] The thermoelectric infrared sensor manufactured at present is formed by the thermoelectric chip and the thermistor respectively, and is mounted on the sub-encapsulation base respectively, the process steps are long, the volume is large, and the reliability is long due to the external connection of the wires.

[0031] The thermoelectric infrared sensor and the manufacturing method thereof of the present application will be further described in detail below in combination with the drawings and specific embodiments. According to the following description and drawings, the advantages and features of the present application will be more apparent, however, it should be noted that the technical solutions of the present application can be implemented in various different forms, and are not limited to the specific embodiments described herein. The drawings are all in a very simplified form and use non-precise proportions, only for the purpose of facilitating and clearly assisting the description of the embodiments of the present application.

[0032] The terms "first", "second", and the like in the description and in the claims are used to distinguish between like elements, and are not necessarily used to describe a particular sequential or chronological order. It is to be understood that, where appropriate, the terms so used can be interchangeable, such that the embodiments of the application described herein can operate in other sequences than described or illustrated herein. Similarly, if a method is described herein, it is understood that the steps of the method can be performed in any order, unless otherwise specifically noted, and that some steps can be omitted, or other steps added, without departing from the scope of the method. Where components of a figure are identical to components of other figures, and these components are readily identifiable in all of the figures, the description will not label all of the identical components in every figure.

[0033] Example 1

[0034] The embodiment 1 provides a thermoelectric infrared sensor, Figure 1 The cross-sectional structure schematic diagram of the thermoelectric infrared sensor provided in the embodiment 1 of the present application is shown in the following figure. Figure 1The thermoelectric infrared sensor comprises:

[0035] The carrier substrate 1 provided with the film-shaped thermistor 2 comprises a first surface 11 and a second surface 12.

[0036] The thermoelectric structure 3 comprises a first substrate 31 provided with a first cavity 311 and a thermoelectric body 32 arranged on the first substrate 31, the thermoelectric body 32 being composed of at least one thermocouple pair, and the first substrate 31 being arranged on the first surface 11 of the carrier substrate 1.

[0037] In the embodiment, the thermistor 2 can be located on the first surface 11 or the second surface 12 of the carrier substrate 1 or inside the carrier substrate 1, so as to be formed in the same package structure with the thermoelectric structure, thereby realizing integrated packaging.

[0038] When the thermistor 2 is located on the first surface 11 of the carrier substrate 1 beyond the range of the first cavity 311, the thermistor 2 is partially embedded in the first substrate 31; when the thermistor 2 is located on the first surface 11 of the carrier substrate 1 within the range of the first cavity 311, the first cavity 311 exposes at least part of the thermistor 2, that is, the part of the thermistor 2 protruding from the first surface 11 of the carrier substrate 1 is exposed to the first cavity 311. It should be noted that the thermoelectric structure 3 comprises a hot end and a cold end, the hot end being located above the first cavity 311, and the cold end being away from the first cavity 311. When the thermistor 2 is located on the first surface 11 of the carrier substrate 1 beyond the range of the first cavity 311, the thermistor 2 is close to the cold end, so as to obtain a more accurate cold end temperature of the thermistor 2, thereby improving the measurement accuracy of the sensor. When the thermistor 2 is located on the first surface 11 of the carrier substrate 1 within the range of the first cavity 311, the first cavity 311 prevents the heat absorbed by the thermoelectric body 32 from being transmitted to the carrier substrate 1, so as to avoid the influence of the temperature of the hot end above the first cavity 311 on the measurement result of the thermistor 2, thereby improving the measurement accuracy.

[0039] When the thermistor 2 is located on the second surface 12 of the carrier substrate 1, the thermistor 2 protrudes from the second surface 12 of the carrier substrate 1, so as to be directly electrically connected with the outside, thereby saving the process steps, shortening the process time and improving the production efficiency.

[0040] The thermistor 2 is arranged in the carrier substrate 1 in one of the following manners: the thermistor 2 is entirely wrapped in the carrier substrate 2; or the thermistor 2 is embedded in the carrier substrate 1 with its upper surface flush with the first surface 11 of the carrier substrate 1; or the thermistor 2 is embedded in the carrier substrate 1 with its lower surface flush with the second surface 12 of the carrier substrate 1. By arranging the thermistor 2 in the carrier substrate 1, the thermistor 2 is prevented from being affected by the hot end temperature or the cold end temperature of the thermoelectric element body 32, so that the thermistor 2 cannot measure the ambient temperature of the thermoelectric element structure 3 accurately, and the measurement accuracy of the thermistor 2 is improved.

[0041] Specifically, the carrier substrate 1 can be any suitable substrate material known to those skilled in the art, such as silicon (Si), germanium (Ge), silicon-germanium (SiGe), silicon-carbon (SiC), silicon-germanium-carbon (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III / V compound semiconductors, and can also be a ceramic substrate such as aluminum oxide, a quartz substrate, a glass substrate, or the like.

[0042] The thermoelectric element structure 3 is formed on the first surface 11 of the carrier substrate 1, and includes a first substrate 31 having a first cavity 311, and a thermoelectric element body 32 formed by at least one pair of thermocouples, which is arranged on the first substrate 31 and covers the first cavity 311, and the first cavity 311 exposes part of the first surface 11 of the carrier substrate 1. The pair of thermocouples includes two thermoelectric materials that are electrically connected to each other, and a plurality of pairs of thermocouples can be arranged in series to achieve high sensitivity of the infrared thermoelectric sensor, thereby improving the quality and reliability of the sensor. The two thermoelectric materials can be arranged side by side in the same horizontal plane, or can be stacked in a direction perpendicular to the carrier substrate 1.

[0043] In order to facilitate electrical connection of the thermoelectric element body 32 to the outside, a connecting bump 4 is arranged between the carrier substrate 1 and the first substrate 31, the thermoelectric element body 32 is provided with a first electrical connection structure 5 for electrically connecting the thermoelectric element body 32 and the connecting bump 4, the carrier substrate 1 is provided with a first interconnection structure 6 for electrically leading out the connecting bump 4, and the first interconnection structure 6 is electrically connected to an external circuit. In this embodiment, the first electrical connection structure 5 includes a plug and an interconnection line, the interconnection line is arranged on the upper surface of the thermoelectric element body 32 and electrically leads out the thermoelectric element body 32, the plug penetrates the thermoelectric element body 32 and the first substrate 31, and electrically connects the interconnection line to the connecting bump 4, thereby electrically leading out the thermoelectric element body 32.

[0044] In order to avoid interference between the monitoring signal of the thermistor 2 and the monitoring signal of the thermoelectric structure 3, the thermoelectric structure 3 and the thermistor 2 need to be electrically connected to the external circuit respectively, so as to improve the measurement accuracy. Specifically, when the thermistor is embedded in the bearing substrate 1 as a whole: the bearing substrate 1 is provided with a second interconnection structure 7, and the second interconnection structure 7 electrically connects the thermistor 2 to the external circuit. When the thermistor 2 is arranged on the first surface 11 of the bearing substrate 1, or the lower surface of the thermistor 2 is embedded in the bearing substrate 1, and the upper surface of the thermistor 2 is flush with the first surface 11 of the bearing substrate 1: the thermistor 2 is electrically connected to the connection bump 4 through the wiring layer, and the reference Figure 2 When the thermistor 2 is arranged on the second surface 12 of the bearing substrate 1, or the upper surface of the thermistor 2 is embedded in the bearing substrate 1, and the lower surface of the thermistor 2 is flush with the second surface 12 of the bearing substrate 1: the thermistor 2 is electrically connected to the external circuit, and the reference Figure 3 .

[0045] The shape of the thermistor 2 includes a line-shaped surface electrode arranged in an S shape or a spiral shape. The material of the thermistor 2 can be a material with a negative temperature coefficient or a material with a positive temperature coefficient. The material of the thermistor 2 includes one, two or more than two metals or metal oxides such as aluminum, copper, nickel, chromium, iron, titanium, gold, silver, platinum, manganese, cobalt, zinc, etc.; or the thermistor includes a semiconductor material layer; or the thermistor includes a heavy metal doped semiconductor layer, and the ions of the heavy metal doping are one or more of aluminum, copper, gold, platinum, silver, nickel, iron, manganese, molybdenum, tungsten, titanium, zinc, mercury, cadmium, chromium and vanadium. In this embodiment, the material of the thermistor 2 is aluminum. The thermistor 2 is in a thin film structure, so that the thermistor 2 has a small volume, a fast thermal response speed and a high sensitivity. The thermistor 2 can be formed by atomic layer deposition or sputtering process, and the specific steps are described below. The thermistor 2 is made by a semiconductor process, which improves the process compatibility compared with the traditional chip form of the mounting structure, and can better realize the integration of the thermistor and the thermoelectric structure, so as to simplify the process and meet the requirements of miniaturization and mass production.

[0046] The bearing substrate 1 is provided with a CMOS circuit, and the CMOS circuit is a readout circuit or a driving circuit; the thermistor 2 is located on the same layer as any one of the metal layers in the CMOS circuit; or the thermistor 2 is located above the CMOS circuit; or the thermistor 2 is located below the CMOS circuit. It should be noted that the thermistor 2 and the CMOS circuit can be electrically connected or not electrically connected. When the thermistor 2 and the CMOS circuit are not electrically connected, the CMOS circuit needs an additional electrical connection structure to electrically connect it to the external circuit. When the thermistor 2 is embedded in the bearing substrate 1 as a whole, the thermistor 2 can be formed when any one of the metal layers of the CMOS circuit 2 is formed.

[0047] In the embodiment, the thermoelectric structure 3 is provided with an annular connecting layer 8, the annular connecting layer 8 has a first opening penetrating through the annular connecting layer 8, the annular connecting layer 8 is provided with a top cover 9, the top cover 9 covers the first opening to form a second cavity 81, and the part of the top cover 9 opposite to the second cavity 81 is provided with an infrared filter layer. Specifically, an infrared radiation penetration window can be formed above the infrared radiation area of the top cover 9, and the material of the top cover 9 can be glass, plastic, semiconductor or the like, so as to transmit infrared light through the infrared radiation penetration window. The shape of the infrared radiation penetration window can be selected as needed, for example, circular, rectangular or the like. The material of the infrared radiation penetration window includes one or both of a semiconductor or an organic filter material. The semiconductor material includes silicon, germanium, silicon-on-insulator or the like, and the organic filter material includes polyethylene, polypropylene or the like. The infrared radiation penetration window can be provided with an infrared filter layer 9. The infrared filter layer 9 filters infrared rays of a specific wavelength, reducing optical crosstalk. The material of the infrared filter layer 9 is an infrared filter.

[0048] The annular connecting layer 8 includes: a first annular protrusion arranged on the thermoelectric structure 3; an annular bonding layer arranged on the first annular protrusion; and a second annular protrusion arranged on the annular bonding layer and bonded to the top cover 9. It should be noted that the bonding mode includes metal bonding, and the materials of the first annular protrusion and the second annular protrusion can be metal materials, which include single-layer, alloy or laminated film of aluminum, titanium, nickel, gold, chromium, copper or platinum.

[0049] In other embodiments, the thermoelectric structure 3 is provided with a top cover having a groove extending to a part of the thickness of the top cover, the top cover and the thermoelectric structure 3 form a second cavity, and the part of the top cover opposite to the second cavity is provided with an infrared filter layer.

[0050] In summary, the embodiments of the present application arrange the thermistor on the carrier substrate, so that the thermoelectric structure and the thermistor can be formed in the same packaging structure at the same time, realizing integrated packaging, shortening the process steps, reducing the volume of the infrared thermopile sensor, and improving the reliability of the infrared thermopile sensor. In addition, the ambient temperature of the thermoelectric structure can be detected by the thermistor, and the temperature signal detected by the thermoelectric structure can be calculated, so as to accurately measure the body temperature, avoid the temperature error caused by the influence of infrared radiation on the thermoelectric structure, and improve the detection accuracy.

[0051] Further, by arranging the thermistor on the first surface, the second surface and the inside of the carrier substrate, the ambient temperature of the thermoelectric structure can be detected by the thermistor, further improving the accuracy and convenience of human sensing.

[0052] Further, the thermoelectric pile structure is electrically led out through the first electric connection structure, and the thermistor is electrically connected to the external circuit, so that the detection signal of the thermoelectric pile structure and the detection signal of the thermistor are prevented from interfering with each other, and measurement error is avoided, and measurement accuracy is improved.

[0053] Further, the top cover with the infrared filter layer is arranged, so that the infrared light is transmitted through the infrared filter layer, and the thermoelectric pile structure detects the temperature; the annular connection layer is arranged, so that the annular connection layer, the top cover and the thermoelectric pile structure jointly form a closed cavity for the second cavity, so that the infrared light is better transmitted to the thermoelectric pile structure, and other light is prevented from interfering with the infrared light.

[0054] Example 2

[0055] Embodiment 2 provides a manufacturing method of a thermoelectric pile infrared sensor, and the manufacturing method of the thermoelectric pile infrared sensor comprises:

[0056] S01: providing a bearing substrate, the bearing substrate comprising opposite first and second surfaces;

[0057] S02: forming a thermistor in the bearing substrate, on the first surface of the bearing substrate or on the second surface of the bearing substrate;

[0058] S03: forming a thermoelectric pile structure, and bonding the thermoelectric pile structure to the first surface of the bearing substrate, wherein the thermoelectric pile structure comprises a first substrate formed on the first surface of the bearing substrate, a thermoelectric pile body formed on the first substrate, a first cavity penetrating through the first substrate formed on the first substrate, the thermoelectric pile body being composed of at least one group of thermocouple pairs, and the thermoelectric pile body covering the first cavity.

[0059] Step S0N does not represent the sequence.

[0060] Figures 4 to 14 The corresponding structure diagram of the corresponding step of the manufacturing method of the thermoelectric pile infrared sensor of the embodiment is shown in Figures 4 to 14 The manufacturing method of the thermoelectric pile infrared sensor provided by the embodiment is described in detail.

[0061] Reference Figure 4 Step S01 is performed to provide a bearing substrate 1 comprising opposite first and second surfaces 11 and 12. The material of the bearing substrate 1 can refer to that described in Embodiment 1, which will not be described here.

[0062] Reference Figures 4-8 Step S02 is performed to form a thermistor 2 in the bearing substrate 1, on the first surface 11 of the bearing substrate 1 or on the second surface 12 of the bearing substrate 1.

[0063] In the present embodiment, the thermistor 2 is formed in the carrier substrate 1, or, when the thermistor 2 is formed on the first surface 11 of the carrier substrate 1: the thermistor 2 is formed before the thermoelectric structure 3 is formed. It should be noted that, when the thermistor 2 is formed in the carrier substrate 1, the thermistor 2 can be completely embedded in the carrier substrate 1, or, the lower surface of the thermistor 2 is embedded in the carrier substrate 1 and the upper surface is flush with the first surface 11 of the carrier substrate 1, or, the upper surface of the thermistor 2 is embedded in the carrier substrate 1 and the lower surface is flush with the second surface 12 of the carrier substrate 1.

[0064] Referring to Figures 4-6 , when the lower surface of the thermistor 2 is embedded in the carrier substrate 1 and the upper surface is flush with the first surface 11 of the carrier substrate 1, or, the upper surface of the thermistor 2 is embedded in the carrier substrate 1 and the lower surface is flush with the second surface 12 of the carrier substrate 1, the method of forming the thermistor 2 in the carrier substrate 1 comprises: providing the carrier substrate 1, referring to Figure 4 ; forming a groove 13 in the carrier substrate 1, referring to Figure 5 ; depositing the thermistor 2, the thermistor 2 filling the groove 13, referring to Figure 6 .

[0065] Referring to Figures 7-8 , when the thermistor 2 is completely embedded in the carrier substrate 1, the method of forming the thermistor 2 in the carrier substrate 1 comprises: providing a first substrate 14, referring to Figure 7 ; depositing the thermistor 2 on the first substrate 14, continuing to refer to Figure 7 ; forming a second substrate 15 on the first substrate 14, the second substrate 15 covering the thermistor 2, referring to Figure 8 , the first substrate 14 and the second substrate 15 constitute the carrier substrate 1. It should be noted that, when the thermistor 2 is deposited on the first substrate 14, a groove can be etched on the first substrate 14; then the thermistor is deposited to fill the groove, and the formed thermistor is embedded in one side of the first substrate 14 and flush with the surface of the first substrate 14 on the other side; or, a thermistor material layer is formed on the first substrate 14; then the thermistor material layer is etched to form the thermistor 2, and the formed thermistor 2 protrudes from the surface of the first substrate 14.

[0066] The method of forming the thermistor 2 on the first surface 11 or the second surface 12 of the carrier substrate 1 comprises: providing a first substrate; depositing a thermistor material layer on the first surface or the second surface of the first substrate; etching the thermistor material layer to form the thermistor. It should be noted that, when the thermistor 2 is formed on the second surface 12 of the carrier substrate 1: the thermistor 2 is formed before or after the thermoelectric structure 3 is bonded to the first surface 11 of the carrier substrate 1.

[0067] In addition, after the thermistor 2 is formed, the connecting bump 4 is formed on the first surface 11 of the carrier substrate 1 before the thermoelectric structure 3 is bonded to the first surface 11 of the carrier substrate 1, so as to facilitate the thermoelectric structure formed subsequently to be electrically led out; the first interconnection structure 6 is formed on the carrier substrate 1 before or after the connecting bump 4 is formed, the first interconnection structure 6 is electrically connected with the external circuit, so as to facilitate the thermoelectric structure formed subsequently to be electrically connected with the external circuit through the connecting bump 4 and the first interconnection structure 6. It should be noted that the forming step of the connecting bump 4 can refer to the forming step of the thermistor 2 when the lower surface of the thermistor 2 is embedded in the carrier substrate 1 and the upper surface is flush with the first surface 11 of the carrier substrate, or when the upper surface of the thermistor 2 is embedded in the carrier substrate 1 and the lower surface is flush with the second surface 12 of the carrier substrate; when the lower surface of the thermistor 2 is embedded in the carrier substrate 1 and the upper surface is flush with the first surface 11 of the carrier substrate, or when the upper surface of the thermistor 2 is embedded in the carrier substrate 1 and the lower surface is flush with the second surface 12 of the carrier substrate, the connecting bump 4 can be formed synchronously with the thermistor 2, which will not be described herein. In other embodiments, the connecting bump 4 can also be formed after the thermoelectric structure is formed, which can refer to the prior art, which will not be described herein.

[0068] In order to electrically connect the thermistor 2 with the external circuit, it is also necessary to make specific arrangements according to the forming position of the thermistor 2. For example, referring to Figure 9 When the thermistor 2 is formed on the first surface 11 of the carrier substrate 1, or the thermistor 2 is formed in the carrier substrate 1 and the upper surface of the thermistor 2 is flush with the first surface 11 of the carrier substrate 1, it further comprises: forming a wiring layer on the carrier substrate 1 before the thermoelectric structure is bonded to the first surface 11 of the carrier substrate 1, so as to electrically connect the thermistor 2 with the connecting bump 4. Referring to Figure 10 When the thermistor 2 is formed on the second surface 12 of the carrier substrate 1, or the thermistor 2 is formed in the carrier substrate 1 and the lower surface of the thermistor 2 is flush with the second surface 12 of the carrier substrate 1, it further comprises: electrically connecting the thermistor 2 with the external circuit after the thermoelectric structure 3 is bonded to the first surface 11 of the carrier substrate 1, and more specifically, electrically connecting the thermistor 2 with the external circuit after the thermoelectric structure 3 is electrically connected with the external circuit. Referring to Figure 11 When the thermistor 2 is embedded in the carrier substrate 1 as a whole, it further comprises: forming a second interconnection structure 7 on the carrier substrate 1 after the carrier substrate 1 is formed, so as to electrically lead the thermistor 2 out to the external circuit.

[0069] In the present embodiment, the CMOS circuit can also be formed in the carrier substrate 1 before or after the thermistor 2 is formed in the carrier substrate 1, so that the formed thermistor 2 is located below or above the CMOS circuit. In other embodiments, the thermistor 2 is formed in the carrier substrate 1 when the CMOS circuit is formed in the carrier substrate 1. It should be noted that the thermistor 2 is formed when any metal layer of the CMOS circuit is formed, so that the formed thermistor 2 is located in the same layer as the metal layer.

[0070] Referring to Figures 12-13 , step S03 is performed to form a thermoelectric structure 3, and the thermoelectric structure 3 is bonded to the first surface 11 of the carrier substrate 1. The thermoelectric structure 3 includes a first substrate 31 formed on the first surface 11 of the carrier substrate 1, and a thermoelectric body 32 formed on the first substrate 31. The first substrate 31 has a first cavity 311 formed therethrough. The thermoelectric body 32 is formed by at least one pair of thermocouples, and covers the first cavity 311.

[0071] In the present embodiment, referring to Figure 12 , the thermoelectric structure 3 is formed first. The method for forming the thermoelectric structure 3 includes forming an isolation layer 33 on the first substrate 31. The isolation layer 33 is used to isolate the thermoelectric body 32 formed later from the first substrate 31, and also serves as a support layer for the thermoelectric body 32. The material of the isolation layer 33 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride. The isolation layer 33 is formed by a deposition process or a thermal oxidation process. The thermoelectric body 32 is formed on the isolation layer 33. The thermoelectric body 32 includes at least one pair of thermocouples. The thermocouples are two kinds of thermoelectric materials that are electrically connected to each other. The two kinds of thermoelectric materials can be located in the same plane and arranged side by side, or stacked one on top of the other. Then, an absorption layer is formed on the thermocouples. The absorption layer is used to absorb infrared light and convert it into heat energy. The material of the absorption layer includes one or more of silicon oxide, silicon nitride, silicon carbide, silicon carbon nitride, silicon carbon oxynitride, silicon oxynitride, boron nitride, and boron carbon nitride. The formation process of the absorption layer includes a physical vapor deposition process or a chemical vapor deposition process.

[0072] Referring to Figure 13 , after the thermoelectric structure 3 is formed, the thermoelectric structure 3 is bonded to the first surface 11 of the carrier substrate 1. It should be noted that the thermoelectric structure 3 can be formed before or after the thermistor is formed in the carrier substrate 1, or the thermoelectric structure 3 can be formed when the thermistor is formed in the carrier substrate 1.

[0073] In order to facilitate the electrical connection of the thermoelectric structure to the connecting bump 4, a first electrical connection structure 5 is formed on the thermoelectric structure 3 before or after the thermoelectric structure 3 is bonded to the first surface 11 of the carrier substrate 1, the first electrical connection structure 5 electrically connects the thermoelectric body 31 to the connecting bump 4. Specifically, a through hole is formed through the thermoelectric body 32 and the first substrate 31 to expose at least part of the connecting bump 4; a plug is formed to fill the through hole and cover the surface of the exposed connecting bump 4; an interconnection line is formed to electrically connect the plug and the thermoelectric body 32.

[0074] Reference Figure 14 After the thermoelectric structure 3 is bonded to the first surface 11 of the carrier substrate 1, a ring-shaped connecting layer 8 is formed on the thermoelectric structure 3, the ring-shaped connecting layer 8 has a first opening; a top cover 9 with an infrared filter layer is provided, the top cover 9 is bonded to the ring-shaped connecting layer 8 and covers the first opening to form a second cavity 81. Specifically, a first ring-shaped bump is formed on the thermoelectric body; a top cover 9 with an infrared filter layer is provided, a second ring-shaped bump is formed on the top cover 9; a ring-shaped bonding layer is formed on the first ring-shaped bump or the second ring-shaped bump, and the other ring-shaped bump formed with the ring-shaped bonding layer is bonded to the ring-shaped bonding layer, the bonding can be metal bonding, thereby achieving the bonding of the top cover 9 and the thermoelectric structure 3, and fully ensuring the sealing of the second cavity 81. In other embodiments, a connecting layer is formed on the surface of the thermoelectric body; the connecting layer is etched to form a first opening through the connecting layer, and the connecting layer outside the first opening forms a ring-shaped connecting layer 8; a top cover 9 with an infrared filter layer is provided; the top cover 9 is bonded to the ring-shaped connecting layer 8 and covers the first opening to form a second cavity 81.

[0075] In summary, the embodiments of the present application form a carrier substrate with a thermistor, so that the thermoelectric structure and the thermistor are formed in the same packaging structure, achieving integrated packaging, shortening the process steps, reducing the volume of the infrared sensor, and additionally, the thermistor is formed on the carrier substrate, which can facilitate the detection of the ambient temperature of the thermoelectric structure, thereby avoiding the influence of the environment on the temperature measurement accuracy of the thermoelectric structure, and improving the reliability.

[0076] Further, different formation methods are used according to the formation position of the thermistor relative to the carrier substrate to avoid damage to the thermistor during manufacturing, shorten the process steps, and improve the reliability of the infrared thermoelectric sensor.

[0077] Further, by forming a ring-shaped connecting layer on the thermoelectric structure and then bonding a top cover, a sealed second cavity is formed by the top cover, the ring-shaped connecting layer and the thermoelectric structure, thereby better transmitting infrared light and avoiding interference of other light with the detected infrared light to affect the measurement accuracy.

[0078] It should be noted that each of the embodiments in the specification adopts a relevant manner for description, and the same and similar parts between the embodiments can be referred to each other, and each embodiment focuses on the difference from other embodiments. Especially, for the structural embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the related parts can be referred to the part of the method embodiments.

[0079] The above description is only a description of the preferred embodiments of the present application, and is not any limitation on the scope of the present application. Any modification or modification made by a person skilled in the art according to the above disclosure is within the protection scope of the claims.

Claims

1. A thermopile infrared sensor, characterized by The application relates to a thermal sensor, comprising: a carrier substrate provided with a film-shaped thermal resistor, the carrier substrate comprising opposite first and second surfaces; a thermoelectric structure comprising a first substrate provided with a first cavity and a thermoelectric body arranged on the first substrate, the thermoelectric body being composed of at least one group of thermocouples, the first substrate being arranged on the first surface of the carrier substrate; the thermal resistor is wholly wrapped in the carrier substrate, or the thermal resistor is embedded in the carrier substrate with its upper surface flush with the first surface of the carrier substrate, or the thermal resistor is embedded in the carrier substrate with its lower surface flush with the second surface of the carrier substrate.

2. The thermopile infrared sensor of claim 1, wherein, a connecting bump is arranged between the carrier substrate and the first substrate, the thermoelectric body is provided with a first electrical connection structure for electrically connecting the thermoelectric body and the connecting bump, and the carrier substrate is provided with a first interconnection structure for electrically leading out the connecting bump, the first interconnection structure being electrically connected with an external circuit.

3. The thermopile infrared sensor of claim 2, wherein, when the thermal resistor is embedded in the carrier substrate with its upper surface flush with the first surface of the carrier substrate: the thermal resistor is electrically connected with the connecting bump through a wiring layer; or a second interconnection structure is arranged in the carrier substrate, the second interconnection structure electrically leading out the thermal resistor to an external circuit; when the thermal resistor is embedded in the carrier substrate with its lower surface flush with the second surface of the carrier substrate: the thermal resistor is electrically connected with an external circuit.

4. The thermopile infrared sensor of claim 1, wherein, when the thermal resistor is arranged on the first surface of the carrier substrate within the range of the first cavity, the first cavity exposes at least part of the thermal resistor.

5. The thermopile infrared sensor of claim 1, wherein, the shape of the thermal resistor comprises a linear surface electrode arranged in an S shape or a spiral shape.

6. The thermopile infrared sensor of claim 1, wherein, the material of the thermal resistor comprises one, two or more than two metals or metal oxides selected from aluminum, copper, nickel, chromium, iron, titanium, gold, silver, platinum, manganese, cobalt and zinc; or the thermal resistor comprises a semiconductor material layer; or the thermal resistor comprises a semiconductor layer doped with heavy metals, the ions of the heavy metal doping being one or more of aluminum, copper, gold, platinum, silver, nickel, iron, manganese, molybdenum, tungsten, titanium, zinc, mercury, cadmium, chromium and vanadium.

7. The thermopile infrared sensor of claim 1, wherein, a CMOS circuit is arranged in the carrier substrate, the CMOS circuit being a readout circuit or a driving circuit; the thermal resistor is located at the same layer as any one of the metal layers in the CMOS circuit; or the thermal resistor is located above the CMOS circuit; or the thermal resistor is located below the CMOS circuit.

8. The thermopile infrared sensor of claim 1, wherein, an annular connecting layer is arranged on the thermoelectric structure, the annular connecting layer has a first opening penetrating through the annular connecting layer, a top cover is arranged on the annular connecting layer, the top cover covers the first opening to form a second cavity, and an infrared filter layer is arranged on the part of the top cover opposite to the second cavity; or a top cover is arranged on the thermoelectric structure, the top cover has a groove extending to part of the thickness of the top cover, the top cover and the thermoelectric structure enclose a second cavity, and an infrared filter layer is arranged on the part of the top cover opposite to the second cavity.

9. The thermopile infrared sensor of claim 8, wherein, the annular connecting layer comprises: a first annular bump disposed on the thermoelectric structure; an annular bonding layer disposed on the first annular bump; a second annular bump disposed on the annular bonding layer and connected to the top cover.

10. A method of manufacturing a thermopile infrared sensor, characterized by, comprising: providing a carrier substrate, the carrier substrate comprising opposite first and second surfaces; forming a thermistor within the carrier substrate, on the first surface of the carrier substrate, or on the second surface of the carrier substrate, the thermistor being entirely enclosed within the carrier substrate, or the thermistor being embedded in the carrier substrate with its upper surface flush with the first surface of the carrier substrate, or the thermistor being embedded in the carrier substrate with its lower surface flush with the second surface of the carrier substrate; forming a thermoelectric structure, the thermoelectric structure being bonded to the first surface of the carrier substrate, the thermoelectric structure comprising a first substrate formed on the first surface of the carrier substrate, and a thermoelectric body formed on the first substrate, the first substrate having a first cavity formed therethrough, the thermoelectric body being formed of at least one pair of thermocouples, and the thermoelectric body covering the first cavity.

11. The method of manufacturing a thermopile infrared sensor according to claim 10, wherein, when the thermistor is formed on the first surface of the carrier substrate, the thermistor is formed before the thermoelectric structure is bonded to the first surface of the carrier substrate.

12. The method of manufacturing a thermopile infrared sensor according to claim 10, wherein, when the thermistor is formed on the second surface of the carrier substrate: the thermistor is formed after the thermoelectric structure is bonded to the first surface of the carrier substrate.

13. The method of manufacturing a thermopile infrared sensor according to claim 10, wherein, a method for forming the thermistor within the carrier substrate comprises: providing a carrier substrate; forming a recess in the carrier substrate; depositing a thermistor to fill the recess; or, providing a first substrate; depositing a thermistor on the first substrate; forming a second substrate on the first substrate, the second substrate covering the thermistor, the first and second substrates constituting the carrier substrate.

14. The method of manufacturing a thermopile infrared sensor according to claim 10, wherein, a method for forming the thermistor on the first or second surface of the carrier substrate comprises: providing a first substrate; depositing a thermistor material layer on the first or second surface of the first substrate; etching the thermistor material layer to form the thermistor.

15. The method of manufacturing a thermopile infrared sensor according to claim 10, wherein, forming a connecting bump on the first surface of the carrier substrate before the thermoelectric structure is bonded to the first surface of the carrier substrate; forming a first interconnection structure on the carrier substrate to electrically lead out the connecting bump before or after forming the connecting bump, the first interconnection structure being electrically connected to an external circuit; forming a first electrical connection structure on the thermoelectric structure before or after the thermoelectric structure is bonded to the first surface of the carrier substrate, the first electrical connection structure electrically leading out the thermoelectric body to the connecting bump.

16. The method of manufacturing a thermopile infrared sensor according to claim 15, wherein, when the thermistor is formed on the first surface of the carrier substrate, or when the thermistor is formed within the carrier substrate with its upper surface flush with the first surface of the carrier substrate, the method further comprises: forming a wiring layer on the carrier substrate before bonding the thermoelectric structure to the first surface of the carrier substrate, to electrically connect the thermistor to the connecting bump; the thermistor is formed on the second surface of the carrier substrate, or the thermistor is formed in the carrier substrate, and when the lower surface of the thermistor is flush with the second surface of the carrier substrate, further comprising: after bonding the thermoelectric structure to the first surface of the carrier substrate, electrically connecting the thermistor to an external circuit.

17. The method of manufacturing a thermopile infrared sensor according to claim 10, wherein, when the thermistor is disposed on the first surface of the carrier substrate, or when the thermistor is disposed in the carrier substrate, further comprising: after forming the carrier substrate, forming a second interconnection structure on the carrier substrate to electrically connect the thermistor to an external circuit.

18. The method of manufacturing a thermopile infrared sensor according to claim 10, wherein, before or after forming the thermistor in the carrier substrate, forming a CMOS circuit in the carrier substrate; or, when the CMOS circuit is formed in the carrier substrate, forming the thermistor in the carrier substrate.

19. The method of manufacturing a thermopile infrared sensor according to claim 10, wherein, after bonding the thermoelectric structure to the first surface of the carrier substrate, further comprising: forming an annular connecting layer on the thermoelectric structure, the annular connecting layer having a first opening; providing a top cover having an infrared filter layer, the top cover being bonded to the annular connecting layer and covering the first opening to form a second cavity.

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