Infrared sensor and manufacturing method thereof

Abstract

The invention discloses an infrared sensor and a manufacturing method thereof. The method comprises the following steps: providing a first semiconductor substrate; forming an insulating layer covering the front surface of the first semiconductor substrate; forming an infrared induction stacking layer on the insulating layer, wherein the infrared induction stacking layer sequentially comprises a lower pole plate thin film, a lithium tantalate thin film and an upper pole plate thin film; forming a second semiconductor substrate, wherein a concave part is formed on the front surface of the second semiconductor substrate; and carrying out bonding processing on the front surface of the first semiconductor substrate and the front surface of the second semiconductor substrate so as to enable the concave part to cover the infrared induction stacking layer. The heat preservation performance can be effectively improved, and the gesture recognition operation accuracy is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to an infrared sensor and a manufacturing method thereof. Background Art

[0002] The infrared sensor can receive infrared signals (such as infrared radiation energy from the human body) and detect the infrared signals by converting them into continuously output electrical signals (such as voltage signals).

[0003] In an existing infrared signal detection technology, multiple infrared sensor chips can be set up to receive the changing trend of heat through different infrared sensor chips, determine the movement of the heat source (such as infrared radiation energy of the human body), and thus realize gesture recognition operation.

[0004] The heat source can be moved in a horizontal, vertical, or oblique manner, and can be flexibly set to more movement modes. For example, when the heat source is infrared radiation energy from a human body, the heat source can be moved through appropriate human body movements and / or gestures.

[0005] However, the existing infrared sensor chips have insufficient thermal insulation, resulting in poor accuracy of gesture recognition operations. There is an urgent need for a manufacturing method for infrared sensors that can effectively improve thermal insulation and enhance the accuracy of gesture recognition operations. Summary of the invention

[0006] The technical problem solved by the present invention is to provide an infrared sensor and a manufacturing method thereof, which can effectively improve the heat preservation performance and enhance the accuracy of gesture recognition operation.

[0007] To solve the above technical problems, an embodiment of the present invention provides a method for manufacturing an infrared sensor, comprising: providing a first semiconductor substrate; forming an insulating layer covering the front side of the first semiconductor substrate; forming an infrared sensing stacking layer on the insulating layer, the infrared sensing stacking layer sequentially comprising a lower electrode film, a lithium tantalate film and an upper electrode film; forming a second semiconductor substrate, a recessed portion being formed on the front side of the second semiconductor substrate; bonding the front side of the first semiconductor substrate and the front side of the second semiconductor substrate so that the recessed portion covers the infrared sensing stacking layer.

[0008] Optionally, the infrared sensing stack layer includes a plurality of infrared sensing structures, each of which includes a stack structure of a lower electrode plate film, a lithium tantalate film and an upper electrode plate film; wherein adjacent infrared sensing structures are spaced apart.

[0009] Optionally, the front surface of the second semiconductor substrate has a plurality of recessed portions; wherein, after the front surface of the first semiconductor substrate and the front surface of the second semiconductor substrate are bonded together, the infrared sensing structure of each infrared sensor is covered by a single recessed portion.

[0010] Optionally, the plurality of infrared sensing structures are arranged in an M×N array; wherein M and N are positive integers, and M≥1, N≥1.

[0011] Optionally, an infrared sensing stacked layer is formed on the insulating layer, including: sequentially forming a stacked lower electrode plate film, a lithium tantalate film and an upper electrode plate film on the insulating layer; and etching the stacked lower electrode plate film, the lithium tantalate film and the upper electrode plate film to form the multiple infrared sensing structures.

[0012] Optionally, before forming the insulating layer covering the first semiconductor substrate, the method further includes: forming a plurality of conductive buried layer structures on the first semiconductor substrate; after forming the insulating layer covering the first semiconductor substrate, the method further includes: forming a plurality of plug holes penetrating the insulating layer, each plug hole exposing a portion of the conductive buried layer structure; forming a conductive metal structure inside and on the surface of the plug hole; wherein the lower electrode plate films of different infrared sensing structures are electrically connected to their respective conductive metal structures, and the upper electrode plate films of different infrared sensing structures are electrically connected to their respective conductive metal structures.

[0013] Optionally, a portion of the conductive metal structure is an import-end conductive metal structure for applying electrical signals, and another portion is an export-end conductive metal structure for exporting electrical signals; wherein the conductive buried layer structures coupled to the export-end conductive metal structure are electrically insulated; and at least a portion of the conductive buried layer structures coupled to the import-end conductive metal structure are electrically insulated.

[0014] Optionally, the same process is used to form the lower electrode film on the insulating layer, and to form a conductive metal structure inside and on the surface of a portion of the plug hole.

[0015] Optionally, the same process is used to form the upper electrode film on the lithium tantalate film, and to form a conductive metal structure inside and on the surface of another part of the plug hole.

[0016] Optionally, a portion of the plug holes corresponds to the conductive metal structure at the outlet end, and another portion of the plug holes corresponds to the conductive metal structure at the inlet end.

[0017] Optionally, forming a second semiconductor substrate includes: etching the second semiconductor substrate from the back side of the second semiconductor substrate to form a cover with a lens on the back side of the second semiconductor substrate; wherein the infrared sensing structure of each infrared sensor after bonding is covered by a single lens.

[0018] Optionally, the method for manufacturing the infrared sensor further includes: etching the first semiconductor substrate from the back side of the first semiconductor substrate to form one or more grooves.

[0019] Optionally, the method further includes: forming a third semiconductor substrate; and bonding the back side of the first semiconductor substrate and the third semiconductor substrate so that the third semiconductor substrate covers the trench.

[0020] Optionally, the infrared sensing stacked layer includes multiple infrared sensing structures, each infrared sensing structure includes a stacked structure of a lower electrode film, a lithium tantalate film and an upper electrode film, and there is a gap between adjacent infrared sensing structures; wherein the multiple infrared sensing structures are arranged in an M×N array, and there are multiple grooves; wherein, in a direction perpendicular to the surface of the first semiconductor substrate, the grooves correspond one-to-one to the infrared sensing structures.

[0021] Optionally, the method further includes: forming a reflective material layer on an inner wall of the groove.

[0022] Optionally, the reflective material layer is made of metal material; and forming the reflective material layer on the inner wall of the groove includes: forming the reflective material layer on the inner wall of the groove by a sputtering process.

[0023] Optionally, before etching the semiconductor substrate from the back side of the semiconductor substrate, the semiconductor substrate is thinned from the back side of the semiconductor substrate.

[0024] Optionally, before etching the first semiconductor substrate from the back side of the first semiconductor substrate, thinning the first semiconductor substrate from the back side of the first semiconductor substrate is performed.

[0025] Optionally, the method further comprises: cutting the bonded first semiconductor substrate to obtain a plurality of the infrared sensors; wherein a single recessed portion exists in each infrared sensor and completely covers the infrared sensing stacked layer in the infrared sensor.

[0026] To solve the above technical problems, an embodiment of the present invention provides an infrared sensor, comprising: a first semiconductor substrate and a second semiconductor substrate bonded together; an insulating layer covering the front surface of the first semiconductor substrate; an infrared sensing stacked layer formed on the insulating layer, the infrared sensing stacked layer sequentially comprising a lower electrode film, a lithium tantalate film and an upper electrode film; a recessed portion formed on the front surface of the second semiconductor substrate; wherein the front surface of the first semiconductor substrate and the front surface of the second semiconductor substrate are bonded together so that the recessed portion covers the infrared sensing stacked layer.

[0027] Optionally, the infrared sensing stack layer includes a plurality of infrared sensing structures, each of which includes a stack structure of a lower electrode plate film, a lithium tantalate film and an upper electrode plate film; wherein adjacent infrared sensing structures are spaced apart.

[0028] Optionally, the front surface of the second semiconductor substrate has a plurality of recessed portions; wherein, after the front surface of the first semiconductor substrate and the front surface of the second semiconductor substrate are bonded together, the infrared sensing structure of each infrared sensor is covered by a single recessed portion.

[0029] Optionally, the plurality of infrared sensing structures are arranged in an M×N array; wherein M and N are positive integers, and M≥1, N≥1.

[0030] Optionally, a cover having a lens is formed on the back side of the second semiconductor substrate; wherein the infrared sensing structure of each infrared sensor after bonding is covered by a single lens.

[0031] Optionally, the infrared sensor further includes: one or more grooves located on the back side of the semiconductor substrate.

[0032] Optionally, the infrared sensor further includes: a third semiconductor substrate bonded to the first semiconductor substrate; wherein the back side of the first semiconductor substrate is bonded to the third semiconductor substrate so that the third semiconductor substrate covers the groove.

[0033] Optionally, the plurality of infrared sensing structures are arranged in an M×N array, and the number of the grooves is multiple; wherein, in a direction perpendicular to the surface of the semiconductor substrate, the grooves correspond one-to-one to the infrared sensing structures.

[0034] Optionally, the infrared sensor is obtained by cutting the bonded first semiconductor substrate; wherein a single recessed portion exists in each infrared sensor and completely covers the infrared sensing stacked layer in the infrared sensor.

[0035] Optionally, the infrared sensor is a pyroelectric infrared sensor.

[0036] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0037] In an embodiment of the present invention, a second semiconductor substrate is formed by providing a first semiconductor substrate, forming an insulating layer, and then forming an infrared sensing stacked layer on the insulating layer. A recessed portion is formed on the front side of the second semiconductor substrate. The front side of the first semiconductor substrate and the front side of the second semiconductor substrate are bonded to each other so that the recessed portion covers the infrared sensing stacked layer. The recessed portion is used to insulate the heat received by the infrared sensing stacked layer, thereby effectively improving the thermal insulation of the infrared sensor and enhancing the accuracy of gesture recognition operations.

[0038] Furthermore, the infrared sensing stacking layer includes a plurality of infrared sensing structures, each of which includes a stacking structure of a lower electrode film, a lithium tantalate film and an upper electrode film; wherein, there is a gap between adjacent infrared sensing structures. Compared with the prior art which requires multiple infrared sensor chips to judge the movement of infrared signals chip by chip, in order to reduce the judgment error, the process consistency between chips is required to be high, the accuracy is poor and the production cost is high. The solution in the embodiment of the present invention is adopted, and the infrared sensing stacking layer includes a plurality of infrared sensing structures, each of which includes a stacking structure of a lower electrode film, a lithium tantalate film and an upper electrode film; it is possible to form multiple infrared sensing structures in a single chip, and judge infrared signals one by one. Compared with the prior art which requires multiple chips to judge infrared signals chip by chip, the solution in the embodiment of the present invention is adopted, and the process consistency within a single chip is better, and a better error control effect can be obtained; in addition, due to the adjacent infrared There are intervals between the sensing structures, so the movement of infrared signals (such as infrared radiation energy of the human body) can be judged through independent and spaced infrared sensing results, providing a good foundation for technologies such as gesture recognition; in addition, the infrared sensor in the embodiment of the present invention is formed based on a lithium tantalate film. Compared with the use of a lithium tantalate wafer, there are problems such as high cost, decreased detection rate and relative detection rate due to the excessive thickness of the lithium tantalate, or too low assembly yield due to the excessive thinness of the lithium tantalate. The solution of the embodiment of the present invention is formed in a single chip, so there is no need to consider assembly requirements, and the thickness of the lithium tantalate film can be effectively controlled. The use of a lithium tantalate film with less material requirements can control production costs and improve detection rates and relative detection rates.

[0039] Furthermore, after the front side of the first semiconductor substrate and the front side of the second semiconductor substrate are bonded, the infrared sensing structure of each infrared sensor is covered by a single recessed portion, so that the recessed portion can be used to insulate the heat received by the infrared sensing structure, thereby better improving the thermal insulation of the infrared sensor and further enhancing the accuracy of gesture recognition operations.

[0040] Furthermore, the multiple infrared sensing structures are arranged in an M×N array. Compared with the prior art in which multiple chips are arranged with poor standardization and prone to detection errors, the above-mentioned scheme can reduce the computational complexity of judging the moving direction and distance of the infrared signal through array arrangement, and the process consistency within a single chip is better, which can obtain better error control effect.

[0041] Furthermore, a plurality of infrared sensing structures are formed on the insulating layer, including: sequentially forming a stacked lower electrode film, a lithium tantalate film and an upper electrode film on the insulating layer; etching the stacked lower electrode film, the lithium tantalate film and the upper electrode film to form the plurality of infrared sensing structures. By adopting the above scheme, a plurality of independent and spaced infrared sensing structures can be formed through an etching process on the basis of first forming a large-area stacked film, thereby effectively reducing the process complexity.

[0042] Furthermore, before forming the insulating layer covering the semiconductor substrate, a plurality of conductive buried layer structures are formed on the first semiconductor substrate; after forming the insulating layer covering the front side of the first semiconductor substrate, a plurality of plug holes and conductive metal structures are formed, and the lower electrode plate films of different infrared sensing structures are electrically connected to their respective conductive metal structures, and the upper electrode plate films of different infrared sensing structures are electrically connected to their respective conductive metal structures. By adopting the above scheme, a structure capable of transmitting electrical signals can be formed. Compared with the prior art that requires establishing electrical connections between multiple chips to transmit electrical signals, by adopting the scheme in the embodiment of the present invention, the process consistency within a single chip is better, and a better error control effect can be obtained. In addition, compared with other electrical connection methods (such as wire bonding processes), the area requirement can be reduced and the production cost can be controlled.

[0043] Furthermore, a part of the conductive metal structure is an import-end conductive metal structure for applying electrical signals, and the other part is an export-end conductive metal structure for exporting electrical signals; wherein, the conductive buried layer structures coupled to the export-end conductive metal structure are electrically insulated; and at least a part of the conductive buried layer structures coupled to the import-end conductive metal structure are electrically insulated. By adopting the above scheme, the exported electrical signals can be independent of each other, thereby enabling the signals of multiple independent and spaced-apart infrared sensing structures to be independently exported. In addition, at least a part of the imported electrical signals can be independent of each other, so that when the imported electrical signals are not completely consistent, the electrical signals to be imported can be transmitted to multiple independent and spaced-apart infrared sensing structures according to needs, which helps to more accurately judge the movement of infrared signals (such as infrared radiation energy of the human body) and provides a good foundation for technologies such as gesture recognition.

[0044] Furthermore, by adopting the same process to form the lower electrode film on the insulating layer, and to form a conductive metal structure inside and on the surface of a portion of the plug hole, multiple parts can be formed by adopting the same process, thereby effectively reducing process costs and process complexity, and further improving process consistency within a single chip.

[0045] Furthermore, by adopting the same process to form the upper electrode film on the lithium tantalate film, and to form a conductive metal structure inside and on the surface of another part of the plug hole, multiple parts can be formed by adopting the same process, thereby effectively reducing process costs and process complexity, and further improving process consistency within a single chip.

[0046] Furthermore, the part of the plug hole corresponds to the conductive metal structure at the lead-out end, and the other part of the plug hole corresponds to the conductive metal structure at the lead-in end. By adopting the above process, the conductive metal structure at the lead-out end can be formed by the same process as the lower electrode film, and then the conductive metal structure at the lead-in end can be formed by the same process as the upper electrode film. The same process can be used to form multiple parts, which effectively reduces the process cost and process complexity, is more suitable for the flow direction of carriers, and improves electrical performance.

[0047] Furthermore, the second semiconductor substrate is etched from the back side of the second semiconductor substrate to form a cover with a lens on the back side of the second semiconductor substrate. The infrared sensing structure of each infrared sensor after bonding is covered by a single lens, so that the lens can be used to converge the infrared signal to the corresponding infrared sensing structure through the lens, so as to better acquire the infrared signal, thereby further improving the signal acquisition efficiency and thermal insulation of the infrared sensor.

[0048] Furthermore, the first semiconductor substrate is etched from the back side of the first semiconductor substrate to form one or more grooves, so as to form a groove-shaped heat-insulating cavity, thereby effectively performing heat-insulating treatment on the infrared sensor and improving the device quality.

[0049] Furthermore, the multiple infrared sensing structures are arranged in an M×N array, and there are multiple grooves; wherein, in a direction perpendicular to the surface of the first semiconductor substrate, the grooves correspond one-to-one to the infrared sensing structures, thereby forming a one-to-one insulation cavity with the infrared sensing structure. Compared with a plurality of infrared sensing structures corresponding to a single larger insulation cavity, the above scheme can make the temperature influence between adjacent infrared sensing structures more independent, thereby being able to more accurately judge the infrared signals corresponding to the adjacent infrared sensing structures (such as the infrared radiation energy of the human body).

[0050] Furthermore, a reflective material layer is formed on the inner wall of the groove, thereby further improving the heat insulation effect and the function of the heat insulation cavity.

[0051] Furthermore, the reflective material layer is made of metal material and is formed on the inner wall of the groove by a sputtering process, thereby forming a metal grid by sputtering, thereby effectively improving the uniformity and heat insulation effect of the reflective material layer.

[0052] Furthermore, the first semiconductor substrate after bonding is cut to obtain a plurality of the infrared sensors; wherein a single recessed portion in each infrared sensor completely covers the infrared sensing stacked layer in the infrared sensor, and the infrared sensor is obtained by cutting, the process is simple, and a plurality of infrared sensors can be formed at one time. Furthermore, in combination with the lens of the second semiconductor substrate and the groove formed by the third semiconductor substrate, a plurality of infrared sensors with excellent thermal insulation performance can be formed at one time by cutting. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the cross-sectional structure of an infrared signal detection device in the prior art;

[0054] Figure 2 is a flow chart of a method for manufacturing an infrared sensor in an embodiment of the present invention;

[0055] Figures 3 to 11 is a schematic diagram of a device cross-sectional structure corresponding to each step in a method for manufacturing an infrared sensor in an embodiment of the present invention;

[0056] Figure 12 to Figure 13 is a schematic diagram of a device cross-sectional structure corresponding to some steps in another method for manufacturing an infrared sensor according to an embodiment of the present invention;

[0057] Figures 14 to 17 It is a schematic diagram of a device cross-sectional structure corresponding to some steps in another method for manufacturing an infrared sensor in an embodiment of the present invention.

[0058] Description of reference numerals:

[0059] Infrared signal detection chip 11, conductive column 12, first semiconductor substrate 20, conductive buried layer structure 21, insulating layer 22, plug hole 231, conductive metal structure 232, lower electrode film 23, lithium tantalate film 24, upper electrode film 25, infrared sensing structure 26, plug hole 251, conductive metal structure 252, groove 27, reflective material layer 28, second semiconductor substrate 30, groove mask layer 31, recessed portion 32, lens 33, third semiconductor substrate 40. DETAILED DESCRIPTION

[0060] In the prior art, multiple infrared sensor chips can be set up, and the change trend of heat received by different infrared sensor chips can be used to determine the movement of the heat source (such as infrared radiation energy of the human body), thereby realizing gesture recognition operation.

[0061] Reference Figure 1 , Figure 1 The invention is a schematic diagram of the cross-sectional structure of an infrared signal detection device in the prior art.

[0062] As shown in the figure, the infrared signal detection device may include a plurality of infrared signal detection chips 11, and each infrared signal detection chip 11 is respectively connected to a corresponding conductive column 12 to realize the import and export of electrical signals.

[0063] The material of the conductive pillar 12 may be silicon or metal.

[0064] However, the infrared signal detection chips 11 judge the movement of the infrared signal one by one. In order to reduce the judgment error, the process consistency between the infrared signal detection chips 11 is required to be high, the accuracy is poor and the production cost is high.

[0065] After research, it was found that in an existing improved process, lithium tantalate material is used as a wafer substrate material to obtain a lithium tantalate wafer, and an infrared sensor chip is made on the lithium tantalate wafer.

[0066] Specifically, the infrared signal detection chip 11 formed based on the lithium tantalate wafer can have higher detection sensitivity.

[0067] like Figure 1 The infrared signal detection chip 11 shown may be formed by performing various process steps on a lithium tantalate wafer.

[0068] However, existing infrared sensor chips have insufficient thermal insulation, resulting in poor accuracy in gesture recognition operations.

[0069] In an embodiment of the present invention, a second semiconductor substrate is formed by providing a first semiconductor substrate, forming an insulating layer, and then forming an infrared sensing stacked layer on the insulating layer. A recessed portion is formed on the front side of the second semiconductor substrate. The front side of the first semiconductor substrate and the front side of the second semiconductor substrate are bonded to each other so that the recessed portion covers the infrared sensing stacked layer. The recessed portion is used to insulate the heat received by the infrared sensing stacked layer, thereby effectively improving the thermal insulation of the infrared sensor and enhancing the accuracy of gesture recognition operations.

[0070] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0071] Reference Figure 2 , Figure 2 1 is a flow chart of a method for manufacturing an infrared sensor in an embodiment of the present invention. The method for manufacturing an image sensor may include steps S21 to S25:

[0072] Step S21: providing a first semiconductor substrate;

[0073] Step S22: forming an insulating layer covering the front surface of the first semiconductor substrate;

[0074] Step S23: forming an infrared sensing stacked layer on the insulating layer, wherein the infrared sensing stacked layer sequentially comprises a lower electrode film, a lithium tantalate film and an upper electrode film;

[0075] Step S24: forming a second semiconductor substrate, wherein a recessed portion is formed on the front surface of the second semiconductor substrate;

[0076] Step S25: performing bonding processing on the front surface of the first semiconductor substrate and the front surface of the second semiconductor substrate so that the recessed portion covers the infrared sensing stacked layer.

[0077] Combine the following Figures 3 to 11 Each of the above steps is described below.

[0078] Figures 3 to 11 It is a schematic diagram of the device cross-sectional structure corresponding to each step in a method for manufacturing an infrared sensor in an embodiment of the present invention.

[0079] Reference Figure 3 , providing a first semiconductor substrate 20 , and forming a plurality of conductive buried layer structures 21 on the first semiconductor substrate 20 .

[0080] The first semiconductor substrate 20 may be a silicon substrate, or the material of the first semiconductor substrate 20 may also include germanium, silicon germanium, silicon carbide, gallium arsenide or indium gallium, and the first semiconductor substrate 20 may also be a silicon-on-insulator substrate or a germanium-on-insulator substrate, or a substrate on which an epitaxy layer (Epi layer) is grown. Preferably, the first semiconductor substrate 20 is a lightly doped semiconductor substrate.

[0081] The conductive buried layer structure 21 is used to realize the conductive function, and can be buried between the first semiconductor substrate 20 and the insulating layer. The material of the conductive buried layer structure 21 can be a conductive material, for example, can be selected from: metal material and polysilicon material.

[0082] Specifically, an initial conductive material layer (not shown) can be formed on the surface of the first semiconductor substrate 20, and then a patterned mask layer can be formed on the surface of the initial conductive material layer. Then, using the patterned mask layer as a mask, the initial conductive material layer is etched to obtain a plurality of conductive buried layer structures 21, and then the mask layer is removed.

[0083] Reference Figure 4 , forming an insulating layer 22 covering the first semiconductor substrate 20.

[0084] It should be noted that the insulating layer 22 may cover the first semiconductor substrate 20 and the plurality of conductive buried layer structures 21 .

[0085] Furthermore, the insulating layer 22 may be selected from: a stack of silicon nitride and silicon oxide, a silicon nitride layer, and a silicon oxide layer.

[0086] Reference Figure 5 The lower electrode film 23 is formed on the insulating layer 22, and a plurality of plug holes 231 are formed to penetrate the insulating layer 22, each plug hole 231 exposes a portion of the conductive buried layer structure 21, and a conductive metal structure 232 is formed inside and on the surface of the plug hole 231, wherein the lower electrode films 23 of different infrared sensing structures are electrically connected to their respective conductive metal structures 232.

[0087] It should be pointed out that in the subsequent process, the stacked layers including the lower electrode plate film 23 will be etched to obtain the infrared sensing structure, so there are gaps between the lower electrode plate films 23 of different infrared sensing structures.

[0088] The lower electrode film 23 is used to realize the conductive function, and its material can be a conductive material, for example, can be selected from: metal material and polysilicon material.

[0089] More specifically, the metal material and the polysilicon material can be selected from: gold, platinum, iridium, tungsten, magnesium, molybdenum, platinum-iridium alloy, titanium alloy, graphite, carbon nanotubes, polyethylene dioxythiophene (PEDOT), and the like.

[0090] It should be pointed out that the step of forming a plurality of plug holes 231 penetrating the insulating layer 22 may include: forming a patterned mask layer on the surface of the insulating layer 22, etching the insulating layer 22 using the patterned mask layer as a mask to obtain the plug holes 231 penetrating the insulating layer 22, and then removing the mask layer.

[0091] It should be pointed out that by setting the lower electrode film 23 with different infrared sensing structures to be electrically connected with the respective conductive metal structures 232, the electrical signal of the lower electrode film 23 can be exported through the corresponding part of the conductive metal structure (i.e., the conductive metal structure 232), or vice versa, the electrical signal of the lower electrode film 23 can be imported through the corresponding part of the conductive metal structure (i.e., the conductive metal structure 232).

[0092] In an embodiment of the present invention, before forming the insulating layer 22 covering the first semiconductor substrate 20, a plurality of conductive buried layer structures 21 are formed on the first semiconductor substrate 20; after forming the insulating layer 22 covering the first semiconductor substrate 20, a plurality of plug holes 231 and a conductive metal structure 232 are formed, and the lower electrode films 23 of different infrared sensing structures are electrically connected to their respective conductive metal structures 232. By adopting the above scheme, a structure capable of transmitting electrical signals can be formed. Compared with the prior art that requires electrical connections to be established between multiple chips to transmit electrical signals, by adopting the scheme in the embodiment of the present invention, the process consistency within a single chip is better, and a better error control effect can be obtained. In addition, compared with other electrical connection methods (such as wire bonding processes), the area requirement can be reduced and the production cost can be controlled.

[0093] Furthermore, a portion of the conductive metal structure 232 is an import-end conductive metal structure for applying electrical signals, and another portion is an export-end conductive metal structure for exporting electrical signals; wherein the conductive buried layer structure 21 coupled to the export-end conductive metal structure is electrically insulated; and at least a portion of the conductive buried layer structure 21 coupled to the import-end conductive metal structure is electrically insulated.

[0094] In the embodiment of the present invention, it is possible to achieve mutual independence between the derived electrical signals, thereby enabling the independent export of signals from a plurality of mutually independent and mutually spaced infrared sensing structures. In addition, it is also possible to achieve mutual independence of at least a portion of the imported electrical signals, thereby enabling the electrical signals to be imported to be transmitted to a plurality of mutually independent and mutually spaced infrared sensing structures when the imported electrical signals are not completely consistent as required, which helps to more accurately judge the movement of infrared signals (such as infrared radiation energy of the human body) and provides a good foundation for technologies such as gesture recognition.

[0095] Furthermore, the lower electrode film 23 is formed on the insulating layer 22 , and a conductive metal structure 232 is formed inside and on the surface of a portion of the plug hole 231 by using the same process.

[0096] In the embodiment of the present invention, the lower electrode film 23 is formed on the insulating layer 22, and the conductive metal structure 232 is formed inside and on the surface of a portion of the plug hole 231. Multiple parts can be formed by adopting the same process, which effectively reduces the process cost and process complexity, and further improves the process consistency within a single chip.

[0097] Reference Figure 6 A lithium tantalate film 24 is formed on the surface of the lower electrode film 23 .

[0098] In the embodiment of the present invention, since it is formed in a single chip, there is no need to consider assembly requirements, and the thickness of the lithium tantalate film 24 can be effectively controlled. The lithium tantalate film 24 with less material requirements can be used to control production costs and improve detection rate and relative detection rate.

[0099] Reference Figure 7 An upper electrode film 25 is formed on the surface of the lithium tantalate film 24, and a plurality of plug holes 251 are formed that penetrate the insulating layer 22. Each plug hole 251 exposes a portion of the conductive buried layer structure 21, and a conductive metal structure 252 is formed inside and on the surface of the plug hole 251, wherein the upper electrode films 25 of different infrared sensing structures are electrically connected to their respective conductive metal structures 252.

[0100] It should be pointed out that in the subsequent process, the stacked layers including the upper electrode plate film 25 will be etched to obtain the infrared sensing structure, so there are gaps between the upper electrode plate films 25 of different infrared sensing structures.

[0101] It should be pointed out that by setting the upper electrode film 25 with different infrared sensing structures to be electrically connected with the respective conductive metal structures 252, the electrical signal of the upper electrode film 25 can be introduced through the corresponding other part of the conductive metal structure (i.e., the conductive metal structure 252), or vice versa, the electrical signal of the upper electrode film 25 can be exported through the corresponding other part of the conductive metal structure (i.e., the conductive metal structure 252).

[0102] It should be particularly pointed out that in another specific implementation of the embodiment of the present invention, Figure 5 The steps shown form a plurality of plug holes 231 penetrating the insulating layer 22 while forming the plug hole 251 to improve process efficiency.

[0103] Furthermore, the upper electrode film 25 is formed on the lithium tantalate film 24 , and a conductive metal structure 252 is formed inside and on the surface of another portion of the plug hole 251 by using the same process.

[0104] In the embodiment of the present invention, the same process is adopted to form the upper electrode film 25 on the lithium tantalate film 24, and to form a conductive metal structure 252 inside and on the surface of another part of the plug hole 251. By adopting the same process to form multiple parts, the process cost and process complexity can be effectively reduced, and the process consistency within a single chip can be further improved.

[0105] Further, the part of the plug hole 231 corresponds to the conductive metal structure at the outlet end, and the other part of the plug hole 251 corresponds to the conductive metal structure at the inlet end.

[0106] In the embodiment of the present invention, the part of the plug hole 231 corresponds to the conductive metal structure at the lead-out end, and the other part of the plug hole 251 corresponds to the conductive metal structure at the lead-in end. By adopting the above process, the conductive metal structure at the lead-out end can be formed by the same process as the lower electrode film 23, and then the conductive metal structure at the lead-in end can be formed by the same process as the upper electrode film 25. The same process can be used to form multiple parts, which effectively reduces the process cost and process complexity, is more suitable for the flow direction of carriers, and improves electrical performance.

[0107] Furthermore, the upper electrode film 25 is used to realize the conductive function, and its material can be a conductive material, for example, can be selected from: metal material and polysilicon material.

[0108] More specifically, the metal material and the polysilicon material can be selected from: gold, platinum, iridium, tungsten, magnesium, molybdenum, platinum-iridium alloy, titanium alloy, graphite, carbon nanotubes, polyethylene dioxythiophene (PEDOT), and the like.

[0109] Furthermore, the materials of the lower electrode plate film 23 and the upper electrode plate film 25 may be consistent or inconsistent.

[0110] In a specific implementation of the embodiment of the present invention, the infrared sensing stack layer includes a plurality of infrared sensing structures, each of which includes a stack structure of a lower electrode film, a lithium tantalate film and an upper electrode film; wherein adjacent infrared sensing structures are spaced apart.

[0111] Reference Figure 8 The stacked lower electrode film 23 , lithium tantalate film 24 and upper electrode film 25 are etched to form the plurality of infrared sensing structures 26 , with spaces between adjacent infrared sensing structures 26 .

[0112] In an embodiment of the present invention, a plurality of infrared sensing structures 26 are formed on the insulating layer 22, including: sequentially forming a stacked lower electrode film 23, a lithium tantalate film 24 and an upper electrode film 25 on the insulating layer 22; etching the stacked lower electrode film 23, the lithium tantalate film 24 and the upper electrode film 25 to form the plurality of infrared sensing structures 26. By adopting the above scheme, a plurality of independent and spaced infrared sensing structures 26 can be formed by an etching process on the basis of first forming a large-area stacked film, thereby effectively reducing the process complexity.

[0113] Each infrared sensing structure 26 includes a stacked structure of a lower electrode film 23 , a lithium tantalate film 24 and an upper electrode film 25 .

[0114] In the embodiment of the present invention, since there is a gap between adjacent infrared sensing structures 26, the movement of infrared signals (such as infrared radiation energy of the human body) can be judged through independent and spaced infrared sensing results, providing a good foundation for technologies such as gesture recognition.

[0115] Furthermore, the plurality of infrared sensing structures 26 are arranged in an M×N array; wherein M and N are positive integers, and M≥1, N≥1.

[0116] like Figure 8 The infrared sensing structure 26 shown may be a 3×1 array, which can determine the movement of the infrared signal from left to right in the figure.

[0117] In a specific implementation of the embodiment of the present invention, the infrared sensing structure 26 may be a 3×3 array, which can determine the movement of infrared signals in all directions of up, down, left, and right.

[0118] In the embodiment of the present invention, the multiple infrared sensing structures 26 are arranged in an M×N array. Compared with the prior art in which multiple chips are arranged in an array, the standardization is poor and detection errors are prone to occur. By adopting the above scheme, the computational complexity of judging the moving direction and distance of the infrared signal can be reduced through array arrangement, and the process consistency within a single chip is better, which can obtain better error control effect.

[0119] It should be pointed out that if Figure 8 As shown in the dotted line direction, the lower electrode film 23 of different infrared sensing structures 26 is electrically connected to the respective conductive metal structure 232 , and the upper electrode film 25 of different infrared sensing structures 26 is electrically connected to the respective conductive metal structure 252 .

[0120] In addition, due to Figure 8What is shown is a cross-sectional view, so the infrared sensing structure 26 not shown by dotted lines (such as the middle infrared sensing structure 26) can be electrically connected with its conductive metal structure 232 and conductive metal structure 252 in directions other than the direction shown in the cross-section, which will not be repeated here.

[0121] In an embodiment of the present invention, the infrared sensing stacking layer includes a plurality of infrared sensing structures 26, each infrared sensing structure 26 includes a stacking structure of a lower electrode film 23, a lithium tantalate film 24 and an upper electrode film 25; wherein, there is a gap between adjacent infrared sensing structures 26. Compared with the prior art which requires multiple infrared sensor chips to judge the movement of infrared signals chip by chip, in order to reduce the judgment error, the process consistency requirements between chips are high, the accuracy is poor and the production cost is high. By adopting the scheme in the embodiment of the present invention, it is possible to form multiple infrared sensing structures 26 in a single chip, and judge the infrared signals by the infrared sensing structures 26 one by one. Compared with the prior art which requires multiple chips to judge the infrared signals chip by chip, by adopting the scheme in the embodiment of the present invention, the process consistency within a single chip is better, and a better error control effect can be obtained; in addition, since there is a gap between adjacent infrared sensing structures 26, it is possible to achieve the effect of error control by being independent and spaced apart from each other. The infrared sensing results can be used to judge the movement of infrared signals (such as infrared radiation energy of the human body), providing a good foundation for technologies such as gesture recognition. In addition, the infrared sensor in the embodiment of the present invention is formed based on a lithium tantalate film 24. Compared with the use of a lithium tantalate wafer, there are problems such as high cost, decreased detection rate and relative detection rate due to the lithium tantalate being too thick, or a problem of too low assembly yield due to the lithium tantalate being too thin. The solution of the embodiment of the present invention is formed in a single chip, so there is no need to consider assembly requirements, and the thickness of the lithium tantalate film 24 can be effectively controlled. The use of a lithium tantalate film 24 with less material requirements can control production costs and improve detection rate and relative detection rate.

[0122] Reference Fig. 9 , forming a second semiconductor substrate 30 , and forming a patterned groove mask layer 31 on the surface of the second semiconductor substrate 30 .

[0123] The second semiconductor substrate 30 may be a silicon substrate, or the material of the second semiconductor substrate 30 may also include germanium, silicon germanium, silicon carbide, gallium arsenide or indium gallium, and the second semiconductor substrate 30 may also be a silicon substrate on an insulator or a germanium substrate on an insulator, or a substrate on which an epitaxy layer (Epi layer) is grown. Preferably, the second semiconductor substrate 30 is a lightly doped semiconductor substrate.

[0124] The material of the second semiconductor substrate 30 may be consistent with or different from the material of the first semiconductor substrate 20 .

[0125] Reference Fig.10 , using the groove mask layer 31 as a mask, the second semiconductor substrate 30 is etched to obtain a recessed portion 32 .

[0126] Reference Fig.11 , a bonding process is performed on the front surface of the first semiconductor substrate 20 and the front surface of the second semiconductor substrate 30 so that the recessed portion 32 covers the infrared sensing stacked layer.

[0127] After the front surface of the first semiconductor substrate 20 and the front surface of the second semiconductor substrate 30 are bonded together, the infrared sensing structure 26 of each infrared sensor is covered by a single recess 32 .

[0128] by Fig.11 Taking the example of a single infrared sensor including an infrared sensing stacked layer including three infrared sensing structures 26 , a single recessed portion 32 may cover the three infrared sensing structures 26 .

[0129] In an embodiment of the present invention, after the front side of the first semiconductor substrate 20 and the front side of the second semiconductor substrate 30 are bonded, the infrared sensing structure 26 of each infrared sensor is covered by a single recessed portion 32, so that the recessed portion 32 can be used to insulate the heat received by the infrared sensing structure 26, thereby better improving the thermal insulation of the infrared sensor and further enhancing the accuracy of gesture recognition operations.

[0130] It should be pointed out that in Fig.11 Only a single recess 32 is used as an example for illustration; however, there are actually multiple recesses 32 spaced apart from each other on the entire semiconductor substrate 30. After the bonded first semiconductor substrate 20 is cut in a subsequent process to obtain multiple infrared sensors, at least a single recess 32 corresponding to a single infrared sensor will be obtained.

[0131] In an embodiment of the present invention, a second semiconductor substrate 30 is formed by providing a first semiconductor substrate 20, forming an insulating layer 22, and then forming an infrared sensing stacking layer on the insulating layer 22. A recessed portion 32 is formed on the front side of the second semiconductor substrate 30. The front side of the first semiconductor substrate 20 and the front side of the second semiconductor substrate 30 are bonded to each other so that the recessed portion 32 covers the infrared sensing stacking layer. The recessed portion 32 is used to insulate the heat received by the infrared sensing stacking layer, thereby effectively improving the thermal insulation of the infrared sensor and enhancing the accuracy of gesture recognition operations.

[0132] In another method for manufacturing an infrared sensor in an embodiment of the present invention, the second semiconductor substrate 30 is a cover having a lens.

[0133] Figure 12 to Figure 13 It is a schematic diagram of a device cross-sectional structure corresponding to some steps in another method for manufacturing an infrared sensor in an embodiment of the present invention.

[0134] Specifically, Fig.12 The infrared sensor shown can be Fig.10 continued to be implemented on the basis of.

[0135] Reference Fig.12 , the second semiconductor substrate 30 is etched from the back side of the second semiconductor substrate 30 to form a cover having a lens 33 on the back side of the second semiconductor substrate 30 .

[0136] Specifically, the step of forming a cap having a lens 33 may include: forming a patterned photoresist layer (not shown) on the back side of the second semiconductor substrate 30; heating the photoresist layer to form one or more photoresist blocks, the shape, size, and position of the photoresist blocks defining the shape, size, and position of the lens to be formed; using the photoresist blocks as masks, etching the back side of the second semiconductor substrate 30 to form a lens 33 defined by the photoresist blocks on the back side of the second semiconductor substrate 30, thereby obtaining a cap having a lens 33.

[0137] It should be pointed out that it is also possible to Fig. 9 Based on the above, a step of first forming a cover having a lens 33 on the back side of the second semiconductor substrate 30 is performed, and then performing Fig.10 The step of forming the recessed portion 32 is shown.

[0138] Reference Fig.13 The front side of the first semiconductor substrate 20 and the front side of the second semiconductor substrate 30 are bonded together, and after bonding, the infrared sensing structure 26 of each infrared sensor is covered by a single lens 33 .

[0139] In an embodiment of the present invention, the second semiconductor substrate 20 is etched from the back side of the second semiconductor substrate 20 to form a cover having a lens 33 on the back side of the second semiconductor substrate 20. After bonding, the infrared sensing structure 26 of each infrared sensor is covered by a single lens 33, so that the lens 33 can be utilized to converge the infrared signal through the lens 33 to the corresponding infrared sensing structure 26, so as to better acquire the infrared signal and further improve the signal acquisition efficiency and thermal insulation of the infrared sensor.

[0140] In yet another method for manufacturing an infrared sensor in an embodiment of the present invention, a groove may be formed on the back surface of the first semiconductor substrate 20 and a third semiconductor substrate may be used for bonding.

[0141] Figures 14 to 17It is a schematic diagram of a device cross-sectional structure corresponding to some steps in another method for manufacturing an infrared sensor in an embodiment of the present invention.

[0142] It should be pointed out that Fig.14 It can be in Fig.11 The infrared sensor shown continues to perform, however Fig.14 You can also Fig.13 The infrared sensor shown is continued on the basis of the above.

[0143] Reference Fig.14 , the first semiconductor substrate 20 is etched from the back side of the first semiconductor substrate 20 to form one or more grooves 27.

[0144] In the embodiment of the present invention, the first semiconductor substrate 20 is etched from the back side of the first semiconductor substrate 20 to form one or more grooves 27, which can form a groove-shaped thermal insulation cavity, effectively performing thermal insulation treatment on the infrared sensor and improving the device quality.

[0145] Furthermore, the infrared sensing stacking layer includes a plurality of infrared sensing structures 26, each infrared sensing structure 26 includes a stacking structure of a lower electrode film 23, a lithium tantalate film 24 and an upper electrode film 25, and there is a gap between adjacent infrared sensing structures 26; wherein the plurality of infrared sensing structures 26 are arranged in an M×N array, and there are a plurality of grooves 27; wherein, in a direction perpendicular to the surface of the first semiconductor substrate 20, the grooves 27 correspond one-to-one to the infrared sensing structures 26.

[0146] In the embodiment of the present invention, the plurality of infrared sensing structures are arranged in an M×N array, and there are a plurality of grooves 27; wherein, in a direction perpendicular to the surface of the first semiconductor substrate 20, the grooves 27 correspond one-to-one to the infrared sensing structures 26, thereby forming a one-to-one insulation cavity with the infrared sensing structures 26. Compared with a plurality of infrared sensing structures 26 corresponding to a single larger insulation cavity, the above scheme can make the temperature influence between adjacent infrared sensing structures 26 more independent, thereby being able to more accurately judge the infrared signals corresponding to the adjacent infrared sensing structures 26 (such as infrared radiation energy of the human body).

[0147] Further, in Fig.14 As shown, the first semiconductor substrate 20 is thinned from the back side of the first semiconductor substrate 20 before being etched.

[0148] In the embodiment of the present invention, by performing a thinning process on the first semiconductor substrate 20 , the thickness of the semiconductor substrate can be controlled, and the difficulty and process complexity of forming the trench 27 can be reduced.

[0149] Reference Fig.15 A reflective material layer 28 is formed on the inner wall of the groove 27 .

[0150] In the embodiment of the present invention, by forming a reflective material layer 28 on the inner wall of the groove 27, the heat insulation effect can be further improved, thereby improving the function of the heat insulation cavity.

[0151] Furthermore, the material of the reflective material layer 28 is a metal material; the step of forming the reflective material layer 28 on the inner wall of the groove 27 includes: forming the reflective material layer 28 on the inner wall of the groove 27 by a sputtering process.

[0152] The metal material may be selected from the group consisting of aluminum, cobalt, titanium, silver, gold, tin, cadmium, platinum, iridium, tungsten, magnesium, molybdenum, platinum-iridium alloy, titanium alloy, graphite, carbon nanotubes, and polyethylene dioxythiophene (PEDOT).

[0153] In the embodiment of the present invention, the reflective material layer 28 is formed on the inner wall of the groove 27 by a sputtering process, so that a metal grid can be formed by sputtering, thereby effectively improving the uniformity and heat insulation effect of the reflective material layer 28 .

[0154] Furthermore, after the reflective material layer 28 is formed by sputtering, the reflective material layer 28 may be etched to remove part or all of the reflective material layer 28 on the bottom surface of the groove 27 .

[0155] By adopting the above scheme, the temperature correlation between the groove 27 and the infrared sensing structure 26 on the front side of the first semiconductor substrate 20 can be further improved, so that the change of the infrared signal received by the infrared sensing structure 26 can more significantly affect the temperature change in the groove 27, thereby improving the judgment sensitivity.

[0156] Furthermore, the step of etching the reflective material layer 28 to remove part or all of the reflective material layer 28 on the bottom surface of the groove 27 may include: the farther the infrared sensing structure is from the central area, the smaller the thickness of the reflective material layer 28 retained on the bottom surface of the corresponding groove 27.

[0157] The central area is used to represent a single infrared sensing structure 26 located at the center or multiple infrared sensing structures 26 located at the center.

[0158] Furthermore, along the direction away from the central area of ​​the infrared sensing structure 26 , the thickness of the reflective material layer 28 retained on the bottom surface of the corresponding subsequent groove 27 is 60% to 90% of the thickness of the reflective material layer 28 retained on the bottom surface of the previous groove 27 .

[0159] Specifically, the further away the infrared sensing structure 26 is from the central area, the more seriously the temperature in the groove 27 is lost through the side wall. Therefore, by adopting the above scheme, the temperature correlation between the groove 27 and the infrared sensing structure 26 on the front side of the first semiconductor substrate 20 can be further improved while taking the side wall temperature loss into consideration, so that the change of the infrared signal received by the infrared sensing structure 26 can more significantly affect the temperature change in the groove 27, thereby improving the judgment sensitivity.

[0160] Reference Fig.16 , forming a third semiconductor substrate 40.

[0161] The third semiconductor substrate 40 may be a silicon substrate, or the material of the third semiconductor substrate 40 may also include germanium, silicon germanium, silicon carbide, gallium arsenide or indium gallium, and the third semiconductor substrate 40 may also be a silicon substrate on an insulator or a germanium substrate on an insulator, or a substrate on which an epitaxy layer (Epi layer) is grown. Preferably, the third semiconductor substrate 40 is a lightly doped semiconductor substrate.

[0162] The material of the third semiconductor substrate 40 , the material of the first semiconductor substrate 20 , and the material of the second semiconductor substrate 30 may be consistent or inconsistent.

[0163] Reference Fig.17 , a bonding process is performed on the back side of the first semiconductor substrate 20 and the third semiconductor substrate 40 so that the third semiconductor substrate 40 covers the groove.

[0164] exist Fig.17 The processes on the front and back sides of the third semiconductor substrate 40 shown can be consistent, so the back side of the first semiconductor substrate 20 and the front side of the third semiconductor substrate 40 can be bonded, and the back side of the first semiconductor substrate 20 and the back side of the third semiconductor substrate 40 can also be bonded.

[0165] In an embodiment of the present invention, by bonding the back side of the first semiconductor substrate 20 and the third semiconductor substrate 40, the third semiconductor substrate 40 can be used to seal the groove 27, thereby further insulating the heat in the groove-shaped thermal insulation cavity and better improving the thermal insulation of the infrared sensor signal.

[0166] Furthermore, the manufacturing method of the infrared sensor may also include: cutting the bonded first semiconductor substrate 20 to obtain a plurality of the infrared sensors; wherein a single recessed portion 32 exists in each infrared sensor to completely cover the infrared sensing stacked layer in the infrared sensor.

[0167] In the embodiment of the present invention, the first semiconductor substrate 20 after bonding is cut to obtain a plurality of the infrared sensors; wherein, a single recess 32 is present in each infrared sensor to completely cover the infrared sensing stacked layer in the infrared sensor, and the infrared sensor is obtained by cutting, the process is simple, and a plurality of infrared sensors can be formed at one time. Furthermore, in combination with the lens of the second semiconductor substrate 30 and the groove formed by the third semiconductor substrate 40, a plurality of infrared sensors with excellent thermal insulation performance can be formed at one time by cutting.

[0168] In an embodiment of the present invention, an infrared sensor is also disclosed. Fig.17 , may include: a bonded first semiconductor substrate 20 and a second semiconductor substrate 30; an insulating layer 22, covering the front side of the first semiconductor substrate 20; an infrared sensing stacked layer, formed on the insulating layer 22, the infrared sensing stacked layer sequentially including a lower electrode film 23, a lithium tantalate film 24 and an upper electrode film 25; a recessed portion 32, formed on the front side of the second semiconductor substrate 30; wherein the front side of the first semiconductor substrate 20 and the front side of the second semiconductor substrate 30 are bonded so that the recessed portion 32 covers the infrared sensing stacked layer.

[0169] Furthermore, the infrared sensing stack layer includes a plurality of infrared sensing structures 26 , each of which includes a stack structure of a lower electrode film 23 , a lithium tantalate film 24 and an upper electrode film 25 ; wherein adjacent infrared sensing structures 26 are spaced apart from each other.

[0170] Furthermore, the front surface of the second semiconductor substrate 30 has a plurality of recessed portions 32 ; wherein, after the front surface of the first semiconductor substrate 20 and the front surface of the second semiconductor substrate 30 are bonded, the infrared sensing structure 26 of each infrared sensor is covered by a single recessed portion 32 .

[0171] Furthermore, the plurality of infrared sensing structures 26 are arranged in an M×N array; wherein M and N are positive integers, and M≥1, N≥1.

[0172] Furthermore, the infrared sensor also includes: a plurality of conductive buried layer structures 21 formed on the semiconductor substrate 2; a plurality of plug holes 231 (251) penetrating the insulating layer 22, each plug hole 231 exposing a portion of the conductive buried layer structure 21; a conductive metal structure 232 (252) formed inside and on the surface of the plug hole 231 (251); wherein the lower electrode film 23 of different infrared sensing structures 26 is electrically connected to their respective conductive metal structures 232, and the upper electrode film 25 of different infrared sensing structures 26 is electrically connected to their respective conductive metal structures 252.

[0173] Furthermore, a portion of the conductive metal structure 26 is an import-end conductive metal structure for applying electrical signals, and another portion is an export-end conductive metal structure for exporting electrical signals; wherein the conductive buried layer structures 21 coupled to the export-end conductive metal structure are electrically insulated; and the conductive buried layer structures 21 coupled to the import-end conductive metal structure are electrically conductive or electrically insulated.

[0174] Furthermore, a cover having a lens 33 is formed on the back side of the second semiconductor substrate 30 ; wherein the infrared sensing structure 26 of each infrared sensor after bonding is covered by a single lens 33 .

[0175] Furthermore, the infrared sensor further includes: one or more grooves 27 located on the back side of the first semiconductor substrate 20 .

[0176] Furthermore, the infrared sensor further includes: a third semiconductor substrate 40 bonded to the first semiconductor substrate 20 ; wherein the back surface of the first semiconductor substrate 20 is bonded to the third semiconductor substrate 40 , so that the third semiconductor substrate 40 covers the groove 27 .

[0177] Furthermore, the infrared sensing stacking layer includes a plurality of infrared sensing structures 26, each infrared sensing structure 26 includes a stacking structure of a lower electrode film 23, a lithium tantalate film 24 and an upper electrode film 25, and there is a gap between adjacent infrared sensing structures 26; wherein the plurality of infrared sensing structures 26 are arranged in an M×N array, and there are a plurality of grooves 27; wherein, in a direction perpendicular to the surface of the first semiconductor substrate 20, the grooves 27 correspond one-to-one to the infrared sensing structures 26.

[0178] Furthermore, the infrared sensor further includes: a reflective material layer 28 formed on the inner wall of the groove 27 .

[0179] Furthermore, the reflective material layer 28 is made of metal material; wherein the reflective material layer 28 is formed on the inner wall of the groove 2 by using a sputtering process.

[0180] Furthermore, the infrared sensor is obtained by cutting the bonded first semiconductor substrate 20; wherein, there is a single recessed portion 32 in each infrared sensor that completely covers the infrared sensing stacked layer in the infrared sensor.

[0181] For more information about infrared sensors, please refer to the previous article and Figures 2 to 17 The description is carried out and will not be repeated here.

[0182] Furthermore, the infrared sensor is a pyroelectric infrared sensor.

[0183] Specifically, by using lithium tantalate thin film to form a pyroelectric infrared sensor, the detection effect can be improved.

[0184] Specifically, the pyroelectric infrared sensor is a sensor with great application potential. It can detect infrared rays emitted by humans or certain animals and convert them into electrical signals for output. It is a new type of highly sensitive infrared detection element that can detect infrared rays emitted by the human body. It can detect the changes in the infrared energy radiated by the human body in a non-contact form and convert it into a voltage signal for output. By amplifying the output voltage signal, it can drive various control circuits, such as power switch control, anti-theft and fire alarm, etc.

[0185] It should be understood that the term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article indicates that the associated objects before and after are in an "or" relationship.

[0186] The "plurality" appearing in the embodiments of the present application refers to two or more.

[0187] The first, second, etc. descriptions appearing in the embodiments of the present application are only used for illustration and distinction of the description objects. There is no order, nor do they indicate any special limitation on the number of devices in the embodiments of the present application, and cannot constitute any limitation on the embodiments of the present application.

[0188] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A method for manufacturing an infrared sensor, characterized in that: include: providing a first semiconductor substrate; forming an insulating layer covering the front surface of the first semiconductor substrate; forming an infrared sensing stacked layer on the insulating layer, wherein the infrared sensing stacked layer sequentially comprises a lower electrode film, a lithium tantalate film and an upper electrode film; forming a second semiconductor substrate, wherein a recessed portion is formed on a front surface of the second semiconductor substrate; The front surface of the first semiconductor substrate and the front surface of the second semiconductor substrate are bonded to each other so that the recessed portion covers the infrared sensing stacked layer.

2. The method for manufacturing an infrared sensor according to claim 1, characterized in that: The infrared sensing stack layer includes a plurality of infrared sensing structures, each of which includes a stack structure of a lower electrode film, a lithium tantalate film and an upper electrode film; There are intervals between adjacent infrared sensing structures.

3. The method for manufacturing an infrared sensor according to claim 2, characterized in that: The front surface of the second semiconductor substrate has a plurality of recessed portions; After the front surface of the first semiconductor substrate and the front surface of the second semiconductor substrate are bonded, the infrared sensing structure of each infrared sensor is covered by a single recessed portion.

4. The method for manufacturing an infrared sensor according to claim 2, characterized in that: The plurality of infrared sensing structures are arranged in an M×N array; Wherein, M and N are positive integers, and M≥1, N≥1.

5. The method for manufacturing an infrared sensor according to claim 2, characterized in that: An infrared sensing stacking layer is formed on the insulating layer, comprising: A stacked lower plate film, a lithium tantalate film and an upper plate film are sequentially formed on the insulating layer; and the stacked lower plate film, the lithium tantalate film and the upper plate film are etched to form the plurality of infrared sensing structures.

6. The method for manufacturing an infrared sensor according to claim 5, characterized in that: Before forming the insulating layer covering the front surface of the first semiconductor substrate, the method further includes: forming a plurality of conductive buried layer structures on the first semiconductor substrate; After forming the insulating layer covering the front surface of the first semiconductor substrate, the method further includes: forming a plurality of plug holes penetrating the insulating layer, each plug hole exposing a portion of the conductive buried layer structure; forming a conductive metal structure inside and on the surface of the plug hole; The lower electrode plate films of different infrared sensing structures are electrically connected to their respective conductive metal structures, and the upper electrode plate films of different infrared sensing structures are electrically connected to their respective conductive metal structures.

7. The method for manufacturing an infrared sensor according to claim 6, characterized in that: A portion of the conductive metal structure is an inlet conductive metal structure for applying an electrical signal, and another portion is an outlet conductive metal structure for deriving an electrical signal; Wherein, the conductive buried layer structure coupled to the conductive metal structure at the lead-out end is electrically insulated; At least a portion of the conductive buried layer structure coupled to the lead-in conductive metal structure is electrically insulated.

8. The method for manufacturing an infrared sensor according to claim 7, characterized in that: The lower electrode film is formed on the insulating layer and a conductive metal structure is formed inside and on the surface of a portion of the plug hole by using the same process.

9. The method for manufacturing an infrared sensor according to claim 8, characterized in that: The same process is used to form the upper electrode film on the lithium tantalate film, and to form a conductive metal structure inside and on the surface of another part of the plug hole.

10. The method for manufacturing an infrared sensor according to claim 8 or 9, characterized in that: The part of the plug hole corresponds to the conductive metal structure at the lead-out end, and the other part of the plug hole corresponds to the conductive metal structure at the lead-in end.

11. The method for manufacturing an infrared sensor according to claim 2, characterized in that: forming a second semiconductor substrate, comprising: Etching the second semiconductor substrate from the back side of the second semiconductor substrate to form a cover having a lens on the back side of the second semiconductor substrate; Among them, the infrared sensing structure of each infrared sensor after bonding is covered by a single lens.

12. The method for manufacturing an infrared sensor according to claim 1, characterized in that: Also includes: The first semiconductor substrate is etched from the back side of the first semiconductor substrate to form one or more grooves.

13. The method for manufacturing an infrared sensor according to claim 12, characterized in that: Also includes: forming a third semiconductor substrate; A bonding process is performed on the back side of the first semiconductor substrate and the third semiconductor substrate so that the third semiconductor substrate covers the trench.

14. The method for manufacturing an infrared sensor according to claim 12, characterized in that: The infrared sensing stack layer includes a plurality of infrared sensing structures, each of which includes a stack structure of a lower electrode film, a lithium tantalate film and an upper electrode film, and there is a gap between adjacent infrared sensing structures; Wherein, the plurality of infrared sensing structures are arranged in an M×N array, and the number of the grooves is multiple; In a direction perpendicular to the surface of the first semiconductor substrate, the grooves correspond to the infrared sensing structures one by one.

15. The method for manufacturing an infrared sensor according to claim 12, characterized in that: The method further comprises: A reflective material layer is formed on the inner wall of the groove.

16. The method for manufacturing an infrared sensor according to claim 15, characterized in that: The reflective material layer is made of metal material; Forming a reflective material layer on the inner wall of the groove comprises: The reflective material layer is formed on the inner wall of the groove by a sputtering process.

17. The method for manufacturing an infrared sensor according to claim 12, characterized in that: Before etching the first semiconductor substrate from the back side of the first semiconductor substrate, the first semiconductor substrate is thinned from the back side of the first semiconductor substrate.

18. The method for manufacturing an infrared sensor according to claim 1, characterized in that: Also includes: Cutting the bonded first semiconductor substrate to obtain a plurality of infrared sensors; There is a single recessed portion in each infrared sensor that completely covers the infrared sensing stacked layer in the infrared sensor.

19. An infrared sensor, characterized in that: include: a bonded first semiconductor substrate and a second semiconductor substrate; an insulating layer, covering the front surface of the first semiconductor substrate; An infrared sensing stacked layer is formed on the insulating layer, and the infrared sensing stacked layer sequentially comprises a lower electrode film, a lithium tantalate film and an upper electrode film; a recessed portion formed on the front surface of the second semiconductor substrate; The front surface of the first semiconductor substrate and the front surface of the second semiconductor substrate are bonded so that the recessed portion covers the infrared sensing stacked layer.

20. The infrared sensor according to claim 19, characterized in that: The infrared sensing stack layer includes a plurality of infrared sensing structures, each of which includes a stack structure of a lower electrode plate film, a lithium tantalate film and an upper electrode plate film; There are intervals between adjacent infrared sensing structures.

21. The infrared sensor according to claim 20, characterized in that: The front surface of the second semiconductor substrate has a plurality of recessed portions; After the front surface of the first semiconductor substrate and the front surface of the second semiconductor substrate are bonded, the infrared sensing structure of each infrared sensor is covered by a single recessed portion.

22. The infrared sensor according to claim 20, characterized in that: The plurality of infrared sensing structures are arranged in an M×N array; Wherein, M and N are positive integers, and M≥1, N≥1.

23. The infrared sensor according to claim 20, characterized in that: A cover having a lens is formed on the back side of the second semiconductor substrate; Among them, the infrared sensing structure of each infrared sensor after bonding is covered by a single lens.

24. The infrared sensor according to claim 19, characterized in that: Also includes: One or more trenches are located on the back side of the first semiconductor substrate.

25. The infrared sensor according to claim 24, characterized in that: Also includes: a third semiconductor substrate bonded to the first semiconductor substrate; The back side of the first semiconductor substrate is bonded to the third semiconductor substrate so that the third semiconductor substrate covers the groove.

26. The infrared sensor according to claim 24, characterized in that: The infrared sensing stack layer includes a plurality of infrared sensing structures, each of which includes a stack structure of a lower electrode film, a lithium tantalate film and an upper electrode film, and there is a gap between adjacent infrared sensing structures; Wherein, the plurality of infrared sensing structures are arranged in an M×N array, and the number of the grooves is multiple; In a direction perpendicular to the surface of the first semiconductor substrate, the grooves correspond to the infrared sensing structures one by one.

27. The infrared sensor according to claim 19, characterized in that: The infrared sensor is obtained by cutting the bonded first semiconductor substrate; There is a single recessed portion in each infrared sensor that completely covers the infrared sensing stacked layer in the infrared sensor.

28. The infrared sensor according to claim 19, characterized in that: The infrared sensor is a pyroelectric infrared sensor.

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