Thermocouple sensor and its preparation method

Abstract

The present invention provides a thermocouple sensor and a preparation method thereof. The thermocouple sensor includes a substrate, a thermocouple structure, and a heat collection structure. The first thermocouple part and the second thermocouple part of each thermocouple in the thermocouple structure are arranged in a first direction pointing from the bottom of the substrate to the top of the substrate, forming a double-layer structure. In the same thermocouple, the first end of the first thermocouple part and the first end of the second thermocouple part are joined to form a hot end structure, and a plurality of the hot end structures are arranged around the middle of the isolation dielectric layer, effectively improving the integration degree; the heat transfer structure is opposite to the plurality of hot end structures, and the heat collection structure is arranged on the heat transfer structure, which is beneficial to improving the heat conduction effect from the heat transfer structure to the plurality of hot end structures and enhancing the sensitivity of the thermopile structure.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor device manufacturing, and particularly to a thermocouple sensor and a preparation method thereof. Background Art

[0002] Generally, a thermopile is a single-layer structure. For example, the thermopile sensor chip disclosed in the utility model with the authorization announcement number CN210040257U has multiple thermocouple pairs connected in series arranged at the same height to form a single-layer structure, resulting in a large chip occupation area and low integration.

[0003] Therefore, it is necessary to develop a new type of thermocouple sensor to solve the above problems existing in the prior art. Summary of the Invention

[0004] The purpose of the present invention is to provide a thermocouple sensor and a preparation method thereof to improve the integration and sensitivity.

[0005] To achieve the above purpose, the thermocouple sensor of the present invention includes:

[0006] A substrate, with a cavity structure provided on the back surface of the substrate and an isolation dielectric layer covering the front surface opposite to the cavity structure;

[0007] A thermocouple structure, disposed on the isolation dielectric layer, including a heat transfer structure and a plurality of thermocouples connected in series;

[0008] A heat collection structure, disposed on the top of the heat transfer structure;

[0009] Each thermocouple includes a first thermocouple part and a second thermocouple part to sense temperature and generate a thermoelectromotive force. In the same thermocouple, the first ends of the first thermocouple part and the second thermocouple part are joined to form a hot end structure;

[0010] The first thermocouple part and the second thermocouple part are arranged along a first direction, and the first direction points from the bottom of the substrate to the top of the substrate;

[0011] A plurality of the hot end structures are arranged around the middle of the isolation dielectric layer;

[0012] The heat transfer structure is opposite to a plurality of the hot end structures.

[0013] The beneficial effects of the thermocouple sensor of the present invention are as follows: The first thermocouple part and the second thermocouple part of each thermocouple are arranged in a first direction pointing from the bottom of the substrate to the top of the substrate, forming a double-layer structure. In the same thermocouple, the first end of the first thermocouple part and the first end of the second thermocouple part are joined to form the hot end structure. A number of the hot end structures are arranged around the middle of the isolation dielectric layer, effectively improving the integration degree; the heat transfer structure is opposite to a number of the hot end structures, and the heat collection structure is arranged on the heat transfer structure, which is beneficial to improving the heat conduction effect of the heat transfer structure to the number of hot end structures and enhancing the sensitivity of the thermopile structure.

[0014] Preferably, the heat collection structure includes a heat absorption structure, a heat conduction structure, and a heat conduction support structure that are sequentially connected in the direction towards the heat transfer structure. The beneficial effects are as follows: It is beneficial to improving the heat conduction effect of the heat transfer structure to the number of hot end structures and enhancing the sensitivity of the thermopile structure.

[0015] More preferably, the heat absorption structure, the heat conduction structure, and the heat transfer structure are all layered structures. The heat conduction structure is arranged at the bottom of the heat absorption structure, and the top surface area of the heat transfer structure is smaller than the bottom surface area of the heat absorption structure.

[0016] Preferably, the thermocouple structure further includes a number of series connection structures. Among adjacent two thermocouples, the second end of the first thermocouple part of one thermocouple is serially connected to the second end of the second thermocouple part of the other thermocouple through the series connection structure. The beneficial effects are as follows: When there is a temperature difference between the two ends of one thermocouple, a voltage will be formed. Connecting multiple thermocouples in series can form a parallel connection of multiple voltages, that is, obtain a larger voltage signal, thereby enhancing the sensitivity.

[0017] More preferably, the bottom of the substrate includes a peripheral substrate structure surrounding the cavity structure, and the number of series connection structures is opposite to the peripheral substrate structure.

[0018] More preferably, the cavity structure includes a number of sub-cavity structures. The number of sub-cavity structures divides the bottom of the substrate into a middle substrate structure and the peripheral substrate structure. All the hot end structures of the number of thermocouples are opposite to the sub-cavity structures. Among all the second ends of the number of thermocouples, a part of the second ends is opposite to the middle substrate structure, and another part of the second ends is opposite to the peripheral substrate structure. The beneficial effects are as follows: Improve the integration degree.

[0019] Further preferably, the middle substrate structure and the peripheral substrate structure are connected so that any two of the several sub-cavity structures are not communicated with each other. The beneficial effect is: to improve the support strength of the substrate.

[0020] Preferably, the thermocouple structure further includes a hot-end connection structure. In the same thermocouple, the first end of the first thermocouple part and the first end of the second thermocouple part are connected through the hot-end connection structure to form the hot-end structure. The beneficial effect is: to improve the heat conduction performance.

[0021] Preferably, the thermocouple structure further includes a first external connection part and a second external connection part for externally connecting a voltage. The first external connection part penetrates through part of the isolation dielectric layer and is connected to at least one of the first thermocouple parts, and the second external connection part penetrates through part of the isolation dielectric layer and is connected to at least one of the second thermocouple parts.

[0022] Preferably, the absolute value of the difference between the Seebeck coefficient of the constituent material of the first thermocouple part and the Seebeck coefficient of the constituent material of the second thermocouple part is greater than 1.

[0023] The preparation method of the thermocouple sensor includes the following steps:

[0024] S1: Provide a substrate, form a first isolation dielectric layer on the top surface of the substrate, and then form a number of first thermocouple parts on the top surface of the first isolation dielectric layer, so that the first end of each first thermocouple part faces the middle of the first isolation dielectric layer;

[0025] S2: Form a second isolation dielectric layer covering the top surface of the first isolation dielectric layer and the top surfaces of the several first thermocouple parts, form a number of second thermocouple parts on the second isolation dielectric layer that are arranged opposite to each of the first thermocouple parts one by one, connect the first ends of the relatively arranged first thermocouple parts and the first ends of the second thermocouple parts to obtain a number of thermocouples, and connect the number of thermocouples in series;

[0026] S3: Form a third isolation dielectric layer covering the top surface of the second isolation dielectric layer and the top surfaces of the several thermocouples, form a heat transfer structure on the third isolation dielectric layer, and the first isolation dielectric layer, the second isolation dielectric layer, and the third isolation dielectric layer constitute an isolation dielectric layer covering the top surface of the substrate;

[0027] S4: Form a sacrificial layer covering the top surface of the isolation dielectric layer, form a heat collection structure on the sacrificial layer, and connect the heat collection structure to the heat transfer structure;

[0028] S5: Form a cavity structure at the bottom of the substrate so that the cavity structure is opposite to the several thermocouples;

[0029] S6: Remove the sacrificial layer. Description of the Drawings

[0030] Figure 1 Schematic diagram of the structure of a thermocouple sensor according to an embodiment of the present invention;

[0031] Figure 2 is Figure 1 Schematic diagram of the arrangement of several thermocouples shown;

[0032] Figure 3 is Figure 2 Schematic diagram of the assembly structure of two adjacent hot end couples shown;

[0033] Figure 4 Flowchart of the preparation method of the thermocouple sensor according to an embodiment of the present invention;

[0034] Figure 5 Schematic diagram of the structure obtained after forming a first isolation dielectric layer and a first original thermocouple layer on the top surface of the original substrate according to an embodiment of the present invention;

[0035] Figure 6 is on Figure 5 Schematic diagram of the structure obtained after forming several first thermocouple parts by patterning on the basis of the structure shown;

[0036] Figure 7 is on Figure 6 Schematic diagram of the structure obtained after depositing a second isolation dielectric layer on the basis of the structure shown;

[0037] Figure 8 is on Figure 7 Schematic diagram of the structure obtained after forming several hole structures on the basis of the structure shown;

[0038] Figure 9 is on Figure 8 Schematic diagram of the structure obtained after depositing and patterning with a metal material on the basis of the structure shown;

[0039] Figure 10 is on Figure 9 Schematic diagram of the structure obtained after forming several second thermocouple parts on the basis of the structure shown;

[0040] Figure 11 is on Figure 10 Schematic diagram of the structure obtained after forming an external structure of the thermocouple structure on the basis of the structure shown;

[0041] Figure 12 is on Figure 11 Schematic diagram of the structure obtained after depositing a third isolation dielectric layer and forming a heat transfer cavity on the basis of the structure shown;

[0042] Figure 13 Schematic diagram of the structure obtained after depositing a heat transfer metal and patterning it on the structure shown Figure 12 ;

[0043] Figure 14 Schematic diagram of the structure obtained after depositing a sacrificial layer and forming a support hole structure on the structure shown Figure 13 ;

[0044] Figure 15 Schematic diagram of the structure obtained after forming a heat conduction support structure 163 on the structure shown Figure 14 ;

[0045] Figure 16 Schematic diagram of the structure obtained after forming an original heat conduction structure and an original heat absorption structure on the structure shown Figure 15 ;

[0046] Figure 17 Schematic diagram of the structure obtained after forming a heat conduction structure, a heat absorption structure, and a cavity structure on the structure shown Figure 16 ;

[0047] Figure 18 Schematic diagram of the structure of another thermocouple sensor according to an embodiment of the present invention

[0048] Figure 19 Schematic diagram of the arrangement of several thermocouples shown Figure 18 ; Detailed implementation manners

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art in the field to which the present invention pertains. The words such as "including" used herein mean that the elements or items appearing before the word cover the elements or items listed after the word and their equivalents, without excluding other elements or items

[0050] An embodiment of the present invention provides a thermocouple sensor with high integration and high sensitivity. The thermocouple sensor includes a substrate, a thermocouple structure, and a heat collection structure

[0051] Figure 1 Schematic diagram of the structure of a thermocouple sensor according to an embodiment of the present invention Figure 2For Figure 1 Schematic diagram of the arrangement of several thermocouples shown

[0052] Referring to Figure 1 and Figure 2 , in the thermocouple sensor 1, it includes a substrate 11, a cavity structure 12 is provided on the back of the substrate 11, and an isolation dielectric layer 13 covering the front is opposite to the cavity structure 12. Specifically, one end of the cavity structure 12 is open.

[0053] In some specific embodiments, the substrate 11 is a silicon substrate.

[0054] In some embodiments, the thermocouple structure is disposed on the isolation dielectric layer, including a heat transfer structure and a plurality of thermocouples connected in series. Each of the thermocouples includes a first thermocouple portion and a second thermocouple portion made of different materials. Specifically, referring to Figure 1 and Figure 2 , a plurality of first thermocouple portions 141 and a plurality of second thermocouple portions 142 are disposed on the isolation dielectric layer 13. One of the first thermocouple portions 141 and one of the second thermocouple portions 142 connected to each other form a thermocouple, and a plurality of thermocouples (not marked in the figure) are connected in series. The heat transfer structure 15 is disposed on the isolation dielectric layer 13, and the heat transfer structure 15 is located above the plurality of thermocouples (not marked in the figure).

[0055] In some embodiments, the absolute value of the difference between the Seebeck's coefficient of the material of the first thermocouple portion and the Seebeck's coefficient of the material of the second thermocouple portion is greater than 1.

[0056] In some embodiments, the heat transfer structure 15 is disposed on the top surface of the isolation dielectric layer 13.

[0057] In some specific embodiments, the material of the first thermocouple portion 141 is N-type silicon, and the material of the second thermocouple portion 142 is P-type silicon.

[0058] In some specific embodiments, the material of the first thermocouple portion 141 is P-type silicon, and the material of the second thermocouple portion 142 is N-type silicon.

[0059] In some specific embodiments, the material of the isolation dielectric layer 13 is silicon dioxide.

[0060] In some embodiments, the material of the heat transfer structure 15 is a heat conductive material. In some specific embodiments, the heat conductive material is a metal.

[0061] In some embodiments, the first thermocouple portion and the second thermocouple portion are arranged in a first direction. Specifically, referring toFigure 1 , the first thermocouple part 141 and the second thermocouple part 142 are arranged along the first direction, that is, the B direction shown in the figure, so that the second thermocouple part 142 is directly above the first thermocouple part 141, making reasonable use of the space of the isolation dielectric layer 13 and improving the integration degree.

[0062] In some embodiments, the first direction points from the bottom of the substrate 11 to the top of the substrate 11.

[0063] In some embodiments, each thermocouple part has a first end and a second end. The first end of each thermocouple part is the end close to the middle of the isolation dielectric layer, and the second end is the end far from the middle of the isolation dielectric layer. Refer to Figure 1 , taking the first thermocouple part 141 as an example, the first end 1411 of the first thermocouple part is close to the middle of the isolation dielectric layer 13, and the second end 1412 of the first thermocouple part is far from the middle of the isolation dielectric layer 13 and is opposite along the A direction shown in the figure.

[0064] In the embodiments of the present invention, the hot end structure formed by each thermocouple receives the heat transferred by the heat transfer structure 15 as the measurement end. Since there is a temperature difference between both ends of each thermocouple, a thermoelectric potential is generated. By measuring the magnitude of the thermoelectric potential and determining the measurement temperature according to the certain proportional relationship between the magnitude of the thermoelectric potential and the measured temperature.

[0065] In some embodiments, the thermocouple structure further includes a hot end connection structure. In the same thermocouple, the first end of the first thermocouple part and the first end of the second thermocouple part are connected by the hot end connection structure. Refer to Figure 1 , the first end 1411 of the first thermocouple part and the first end (not marked in the figure) of the second thermocouple part 142, that is, the end close to the middle of the isolation dielectric layer 13, are connected by the hot end connection structure 143 to form a hot end structure and realize heat transfer between different thermocouple layers.

[0066] In some specific embodiments, the constituent material of the hot end connection structure is metal.

[0067] In some embodiments, the first end 1411 of the first thermocouple part is directly connected to the first end of the second thermocouple part to form a hot end structure.

[0068] In some embodiments, several of the hot end structures are arranged around the middle of the isolation dielectric layer. Refer to Figure 1 and Figure 2, the first ends 1411 of several of the first thermocouple portions and the first ends (not marked in the figure) of several of the second thermocouple portions 142 located above the first ends 1411 of several of the first thermocouple portions are all arranged around the middle of the isolation dielectric layer 13, effectively improving the integration degree.

[0069] In some embodiments, the heat collection structure includes a heat absorption structure, a heat conduction structure, and a heat conduction support structure. The heat collection structure is disposed on the top of the heat transfer structure, and the heat transfer structure faces several of the hot end structures. Refer to Figure 1 and Figure 2 , a heat collection structure including a heat absorption structure 161, a heat conduction structure 162, and a heat conduction support structure 163 is disposed on the heat transfer structure 15. The heat absorption structure 161 and the heat conduction structure 162 are stacked, and the heat absorption structure 161 transfers the collected heat energy through the heat conduction structure 162. The heat conduction support structure 163 connects the heat conduction structure 162 and the heat transfer structure 15, and transfers the heat energy of the heat conduction structure 162 to the heat transfer structure 15. The heat transfer structure 15 faces several hot end structures (not shown in the figure) to conduct heat to the several hot end structures (not shown in the figure).

[0070] In some embodiments, several of the hot end structures are all projected onto the bottom surface of the heat conduction structure 15 along Figure 1 the B direction shown.

[0071] In some embodiments, the heat absorption structure 161, the heat conduction structure 162, and the heat transfer structure 15 are all layered structures. The heat conduction structure 162 covers the bottom surface of the heat absorption structure 161, and the top surface area of the heat transfer structure 15 is smaller than the bottom surface area of the heat absorption structure 161, so that the heat absorption structure 161 can obtain sufficient heat energy through a large heat absorption area and realize heat conduction to the heat transfer structure 15.

[0072] In some embodiments, the top surface area of the heat absorption structure 161 is not greater than the top surface area of the isolation dielectric layer 13.

[0073] In some embodiments, refer to Figure 1 , the thermocouple sensor 1 further includes a first external connection portion 17 and a second external connection portion 18. The first external connection portion 17 penetrates through a part of the isolation dielectric layer 13 and is connected to the first thermocouple portion 141 to lead out a first electrode pad, and the second external connection portion 18 penetrates through a part of the isolation dielectric layer 13 and is connected to the second thermocouple portion 142 to lead out a second electrode pad with a polarity opposite to that of the first electrode pad.

[0074] In some embodiments, the first external connection part 17 and the second external connection part 18 are respectively arranged at two ends of at least two thermocouples connected in series that need to lead out electrodes.

[0075] In some specific embodiments, the first external connection part 17 and the second external connection part 18 are made of metals with the same constituent materials.

[0076] Figure 3 For Figure 2 the schematic assembly structure diagram of two adjacent hot ends of the thermocouples shown.

[0077] In some embodiments, the thermocouple structure further includes a plurality of series connection structures. Among two adjacent thermocouples, the second end of the first thermocouple part of one thermocouple is connected in series with the second end of the second thermocouple part of the other thermocouple through the series connection structure. When there is a temperature difference between two ends of a thermocouple, a voltage will be formed. Connecting multiple thermocouples in series can form a parallel connection of multiple voltages, that is, obtain a larger voltage signal, thereby enhancing the sensitivity. Refer to Figures 1 to 3 , each thermocouple has the same structure. Taking the thermocouple including the first thermocouple part 141 and the second thermocouple part 142 as an example, the second end 1412 of the first thermocouple part is connected with a first extending part 21, and the second end (not marked in the figure) of the second thermocouple part opposite to the second end 1412 of the first thermocouple part along the B direction is connected with a second extending part 22. The adjacent thermocouple (not marked in the figure) includes an adjacent first extending part 21' connected to the adjacent first thermocouple part 141", and an adjacent second extending part 22" connected to the adjacent second thermocouple part 142". The adjacent first extending part 21' is connected to the second extending part 22 through the series connection structure 31.

[0078] In some embodiments, refer to Figure 1 and Figure 3 , the part of the substrate 11 except the cavity structure 12 is the peripheral substrate structure, and a plurality of the series connection structures 31 are opposite to the peripheral substrate structure (not marked in the figure) along the B direction.

[0079] The embodiment of the present invention also provides a preparation method of the thermocouple sensor. Refer to Figure 4 , including:

[0080] S1: Provide a substrate, form a first isolation dielectric layer on the top surface of the substrate, and then form a plurality of first thermocouple parts on the top surface of the first isolation dielectric layer, so that the first end of each first thermocouple part faces the middle of the first isolation dielectric layer;

[0081] S2: Form a second isolation dielectric layer covering the top surface of the first isolation dielectric layer and the top surfaces of the plurality of first thermocouple portions. Form a plurality of second thermocouple portions on the second isolation dielectric layer, each of which is disposed opposite to one of the first thermocouple portions. Connect the first ends of the relatively disposed first thermocouple portions and the first ends of the second thermocouple portions to obtain a plurality of thermocouples, and connect the plurality of thermocouples in series;

[0082] S3: Form a third isolation dielectric layer covering the top surface of the second isolation dielectric layer and the top surfaces of the plurality of thermocouples. Form a heat transfer structure on the third isolation dielectric layer. The first isolation dielectric layer, the second isolation dielectric layer, and the third isolation dielectric layer constitute an isolation dielectric layer covering the top surface of the substrate;

[0083] S4: Form a sacrificial layer covering the top surface of the isolation dielectric layer. Form a heat collection structure on the sacrificial layer, and connect the heat collection structure to the heat transfer structure;

[0084] S5: Form a cavity structure at the bottom of the substrate, and make the cavity structure opposite to the plurality of thermocouples;

[0085] S6: Remove the sacrificial layer.

[0086] The following will Figure 1 , Figures 5 - 17 elaborate in detail on the preparation method of the thermocouple sensor.

[0087] Figure 5 FIG. is a schematic diagram of the structure obtained after forming a first isolation dielectric layer and a first original thermocouple layer on the top surface of the original substrate in some embodiments of the present invention. Figure 6 is in Figure 5 FIG. is a schematic diagram of the structure obtained after forming a plurality of first thermocouple portions by patterning on the basis of the shown structure.

[0088] In step S1 of some embodiments, referring to Figure 5 and Figure 6 , the steps of forming a first isolation dielectric layer on the top surface of the original substrate and then forming a plurality of first thermocouple portions on the top surface of the first isolation dielectric layer include: depositing an isolation material on the top surface of the original substrate 51 to form a first isolation dielectric layer 52 covering the top surface of the original substrate 51, and then depositing a first thermocouple material to form a first original thermocouple layer 53 covering the top surface of the first isolation dielectric layer 52. Remove a part of the first original thermocouple layer 53 by patterning to obtain a plurality of the first thermocouple portions 141.

[0089] Figure 7 is in Figure 6 FIG. is a schematic diagram of the structure obtained after depositing and forming a second isolation dielectric layer on the basis of the shown structure.Figure 8 A structural schematic diagram obtained by forming a number of hole structures on the basis of the structure shown Figure 7 afterwards.

[0090] In the step S2 of some embodiments, after forming the second isolation dielectric layer, a number of hot-end connection hole structures, a number of initial external connection hole structures, and a number of series connection hole structures are formed on the second isolation dielectric layer. The number of hot-end connection hole structures exposes part of the top surface of the hot-end structure of each first thermocouple portion. The number of first initial external connection hole structures serves as the first layer of through holes to expose part of the top surface of the thermocouple layer where electrodes need to be led out. The number of series connection hole structures exposes part of the top surface of the first extending portion of each first thermocouple portion. Refer to Figure 7 and Figure 8 , and the isolation material is deposited on the top surface of the first isolation dielectric layer 52 to form a second isolation dielectric layer 71 covering the top surface of the first isolation dielectric layer 52 and the top surfaces of the number of first thermocouple portions 141. After the second isolation dielectric layer 71 is formed, a number of hot-end connection hole structures 81, a number of initial external connection hole structures 82, and a number of series connection hole structures (not labeled in the figure) are formed by patterning.

[0091] Specifically, refer to Figure 3 , Figure 7 and Figure 8 , the number of hot-end connection hole structures 81 is arranged towards the first end portion 1411 of each first thermocouple portion and exposes part of the top surface of the first end portion 1411 of each first thermocouple portion. The number of first initial external connection hole structures 82 is arranged towards the second end portion 1412 of each first thermocouple portion and exposes part of the top surface of the second end portion 1412 of each first thermocouple portion. A number of series connection hole structures (not labeled in the figure) are arranged towards the first extending portion 21 of each first thermocouple portion 141 and expose part of the top surface of each first extending portion 21.

[0092] Figure 9 A structural schematic diagram obtained by depositing and patterning with a metal material on the basis of the structure shown Figure 8 afterwards. Figure 10 A structural schematic diagram obtained by forming a number of second thermocouple portions on the basis of the structure shown Figure 9 afterwards.

[0093] In the step S2 of some embodiments, refer to Figure 3 , Figure 8 and Figure 9, after forming the plurality of hot-end connection hole structures 81, the plurality of initial external connection hole structures 82, and the plurality of series connection hole structures (not labeled in the figure), metal materials are deposited and patterned to fill the plurality of hot-end connection hole structures 81, the plurality of first initial external connection hole structures 81, and the plurality of series connection hole structures (not labeled in the figure), obtaining a plurality of the hot-end connection structures 143, a plurality of first bottom external connection structures 91, and a plurality of the series connection structures 31, and exposing the remaining top surfaces of the top surface of the second isolation dielectric layer 71 except for the top surfaces of the plurality of the hot-end connection structures 143, the top surfaces of the plurality of first bottom external connection structures 91, and the top surfaces of the plurality of the series connection structures 31.

[0094] In the step S2 of some embodiments, referring to Figure 3 , Figure 9 and Figure 10 , after using the second thermocouple material to deposit and form a second original thermocouple layer (not labeled in the figure) covering the top surface of the second isolation dielectric layer 71, the top surface of the hot-end connection structure 143, the top surfaces of the plurality of first bottom external connection structures 91, and the top surfaces of the plurality of the series connection structures 31, then patterning is performed to remove a part of the second original thermocouple layer (not labeled in the figure) to form a plurality of the second thermocouple portions 142, and making the plurality of the second thermocouple portions 142 be in one-to-one correspondence and connected to the plurality of the hot-end connection structures 143 and the plurality of the series connection structures 31, and exposing the top surfaces of the plurality of first bottom external connection structures 91.

[0095] Specifically, each of the second thermocouple portions 142 forms a plurality of thermocouples through the corresponding connection with each of the first thermocouple portions 141 via each of the hot-end connection structures 143; the one-to-one connection of the second extending portions 22 of the plurality of the second thermocouple portions 142 to the plurality of the series connection structures 31 realizes the series connection between different thermocouple portions.

[0096] Figure 11 For Figure 10 a schematic diagram of the structure obtained after forming the external connection structure of the thermocouple structure on the basis of the structure shown.

[0097] In the step S2 of some embodiments, referring to Figure 11, using the metal material to perform the AL-PAD process to form a plurality of first top external connection structures 1001 and a plurality of second external connection parts 18, and making the plurality of first top external connection structures 1001 be correspondingly connected to the plurality of first bottom external connection structures 91 one by one, and the plurality of second external connection parts 18 be correspondingly connected to the plurality of second thermocouple parts 142 one by one. The first top external connection structure 1001 and the first bottom external connection structure 91 constitute the first external connection part 17. The plurality of first external connection parts 17 and the plurality of second external connection parts 18 constitute the external connection structure of the thermocouple.

[0098] Figure 12 For depositing a third isolation dielectric layer and forming a heat transfer cavity on the basis of the structure shown in Figure 11 a schematic diagram of the obtained structure. Figure 13 For depositing a heat transfer metal and patterning on the basis of the structure shown in Figure 12 a schematic diagram of the obtained structure.

[0099] In the step S3 of some embodiments, referring to Figure 12 and Figure 13 , forming a third isolation dielectric layer covering the top surface of the second isolation dielectric layer, the top surfaces of the plurality of thermocouples, and the top surface of the external connection structure, the steps of forming a heat transfer structure on the third isolation dielectric layer include: using the isolation material to deposit and form a third initial isolation dielectric layer (not labeled in the figure) covering the top surface of the second isolation dielectric layer 71, the exposed surfaces of the plurality of second thermocouple parts 142, the exposed surfaces of the plurality of first external connection parts 17, and the exposed surfaces of the plurality of second external connection parts 18, and then patterning the third initial isolation layer (not labeled in the figure) to form a heat transfer cavity 1201 with one end open and a third isolation layer 1202, and making the top surfaces of the plurality of first external connection parts 17 and the plurality of second external connection parts 18 exposed; depositing a heat transfer metal material and then performing CMP polishing to form the heat transfer structure 15 filling the heat transfer cavity 1201, and making the top surfaces of the plurality of first external connection parts 17 and the plurality of second external connection parts 18 exposed. The first isolation dielectric layer 52, the second isolation dielectric layer 71, and the third isolation dielectric layer 1202 together constitute the isolation dielectric layer 13.

[0100] Figure 14 For depositing a sacrificial layer and forming a support hole structure on the basis of the structure shown in Figure 13 a schematic diagram of the obtained structure. Figure 15 For forming a thermal conduction support structure 163 on the basis of the structure shown in Figure 14 a schematic diagram of the obtained structure. Figure 16 For forming a raw heat conduction structure and a raw heat absorption structure on the basis of the structure shown in Figure 15 a schematic diagram of the obtained structure. Figure 17 ForFigure 16 Schematic diagram of the structure obtained after forming a heat conduction structure, a heat absorption structure, and a cavity structure on the shown structure basis.

[0101] In the step S4 of some embodiments, referring to Figures 14 to 17 , the steps of forming a sacrificial layer covering the top surface of the isolation dielectric layer, forming a heat collection structure on the sacrificial layer, and connecting the heat collection structure to the heat transfer structure include:

[0102] After depositing a sacrificial material to form a sacrificial layer 1402 covering the top surface of the isolation dielectric layer 13, a support hole structure 1401 is patterned on the sacrificial layer 1402 to expose a part of the top surface of the heat transfer structure 15 through the support hole structure 1401;

[0103] After depositing a thermally conductive support material to form an initial thermally conductive support layer (not marked in the figure) that fills the support hole structure 1401 and covers the top surface of the sacrificial layer 1402 and then patterning, a thermally conductive support structure 163 that fills the support hole structure 1401 is formed, and the top surface of the sacrificial layer 1402 is exposed;

[0104] After the thermally conductive support structure 163 is formed, a raw heat conduction structure 1601 covering the thermally conductive support structure 163 and the top surface of the sacrificial layer 1402 is deposited using a heat-dispersing material, and then a raw heat absorption structure 1602 covering the top surface of the raw heat conduction structure 1601 is deposited using a heat-absorbing material;

[0105] The raw heat conduction structure 1601 and the raw heat absorption structure 1602 are patterned once to form the heat conduction structure 162 and the heat absorption structure 161; the thermally conductive support structure 163, the heat conduction structure 162, and the heat absorption structure 161 constitute the heat collection structure.

[0106] In the step S5 of some embodiments, referring to Figure 16 and Figure 17 , after the heat conduction structure 162 and the heat absorption structure 161 are formed, the bottom of the original substrate 51 is patterned to form a cavity structure 12, and the cavity structure 12 is opposite to the isolation dielectric layer 13.

[0107] In the step S6 of some embodiments, referring to Figure 1 and Figure 17 , the steps of removing the sacrificial layer include: removing the sacrificial layer 1402 using a chemical etching method to expose the top surface of the isolation dielectric layer 13, the top surfaces of several first external connection parts 17, the top surfaces of several second external connection parts 18, and the other top surfaces of the heat transfer structure 15 except for the part connected to the thermally conductive support structure 163.

[0108] Figure 18 This is a schematic structural diagram of another thermocouple sensor according to an embodiment of the present invention. Figure 19 is Figure 18 a schematic diagram showing the arrangement of several thermocouples as shown.

[0109] In some embodiments, referring to Figure 1 、 Figure 18 and Figure 19 , in another thermocouple sensor 180, the cavity structure 12 includes a plurality of sub-cavity structures 1802. The plurality of sub-cavity structures 1802 divide the bottom of the substrate 11 into a middle substrate structure 1803 and the peripheral substrate structure 1801. The first end (not labeled in the figure) of each thermocouple layer of the plurality of thermocouples faces the sub-cavity structure 1801, and a part of the second end (not labeled in the figure) of each thermocouple layer of the plurality of thermocouples faces the middle substrate structure 1803, and the other part faces the peripheral substrate structure 1801, so as to further improve the integration degree.

[0110] In some embodiments, the middle substrate structure 1803 and the peripheral substrate structure 1801 are connected to each other, so that any two of the plurality of sub-cavity structures 1802 are not communicated with each other, thereby improving the support strength of the substrate.

[0111] In some embodiments, referring to Figure 1 and Figure 18 , in the another thermocouple sensor 180, the heat absorption structure 161 and the heat conduction structure 162 are stacked. Each sub-cavity structure 1802 corresponds to a heat transfer structure 15 provided. Each heat transfer structure 15 is connected to at least one heat conduction support structure 163, and all the heat conduction support structures 163 are connected to the heat conduction structure 162.

[0112] Although the embodiments of the present invention have been described in detail above, it is obvious to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes are all within the scope and spirit of the present invention described in the claims. Moreover, the present invention described herein can have other embodiments and can be implemented or realized in various ways.

Claims

1. A thermocouple sensor, characterized in that, Comprising: A substrate, with a cavity structure provided on the back surface of the substrate and an isolation dielectric layer covering the front surface opposite to the cavity structure; A thermocouple structure, disposed on the isolation dielectric layer, comprising a heat transfer structure and a plurality of thermocouples connected in series; A heat collection structure, disposed on the top of the heat transfer structure; Each thermocouple includes a first thermocouple portion, a second thermocouple portion and a series connection structure to sense temperature and generate a thermoelectromotive force; in the same thermocouple, the first ends of the first thermocouple portion and the second thermocouple portion are joined to form a hot end structure; a first extension is connected to the second end of each first thermocouple portion, and a second extension is connected to the second end of each second thermocouple portion; in two adjacent thermocouples, the first extension of the first thermocouple portion of one thermocouple is connected in series with the second extension of the second thermocouple portion of the other thermocouple through the series connection structure; The first thermocouple portion and the second thermocouple portion are arranged in a first direction, and the first direction points from the bottom of the substrate to the top of the substrate; the second thermocouple portion is located directly above the first thermocouple portion; A plurality of the hot end structures are arranged around the middle of the isolation dielectric layer; The heat transfer structure is opposite to a plurality of the hot end structures.

2. The thermocouple sensor according to claim 1, wherein, The heat collection structure includes an endothermic structure and a heat conduction structure connected in sequence towards the heat transfer structure, and a heat conduction support structure connecting the heat conduction structure and the heat transfer structure.

3. The thermocouple sensor according to claim 2, characterized in that, The endothermic structure, the heat conduction structure and the heat transfer structure are all layered structures, the heat conduction structure is disposed at the bottom of the endothermic structure, and the top surface area of the heat transfer structure is smaller than the bottom surface area of the endothermic structure.

4. The thermocouple sensor according to claim 1, wherein The bottom of the substrate includes a peripheral substrate structure surrounding the cavity structure, and the plurality of series connection structures are opposite to the peripheral substrate structure.

5. The thermocouple sensor according to claim 4, characterized in that, The cavity structure includes a plurality of sub-cavity structures, the plurality of sub-cavity structures divide the bottom of the substrate into a middle substrate structure and the peripheral substrate structure, all the hot end structures of the plurality of thermocouples are opposite to the sub-cavity structures, and among all the second ends of the plurality of thermocouples, a part of the second ends are opposite to the middle substrate structure, and the other part of the second ends are opposite to the peripheral substrate structure.

6. The thermocouple sensor according to claim 5, wherein, The middle substrate structure and the peripheral substrate structure are connected so that any two of the plurality of sub-cavity structures are not in communication with each other.

7. The thermocouple sensor according to claim 1, characterized in that, The thermocouple structure further includes a hot end connection structure, and in the same thermocouple, the first ends of the first thermocouple portion and the second thermocouple portion are joined through the hot end connection structure to form the hot end structure.

8. The thermocouple sensor according to claim 1, characterized in that, The thermocouple structure further includes a first external connection portion and a second external connection portion for externally connecting a voltage, the first external connection portion penetrates through a part of the isolation dielectric layer and is connected to at least one first thermocouple portion, and the second external connection portion penetrates through a part of the isolation dielectric layer and is connected to at least one second thermocouple portion.

9. The thermocouple sensor according to claim 1, wherein, The absolute value of the difference between the Seebeck coefficient of the constituent material of the first thermocouple portion and the Seebeck coefficient of the constituent material of the second thermocouple portion is greater than 1.

10. A method for preparing a thermocouple sensor, which is used to manufacture the thermocouple sensor according to any one of claims 1 to 9, characterized in that, It includes the following steps: S1: Provide a substrate, form a first isolation medium layer on the top surface of the substrate, and then form a number of first thermocouple parts on the top surface of the first isolation medium layer, with the first end of each first thermocouple part facing the middle of the first isolation medium layer; S2: Form a second isolation medium layer covering the top surface of the first isolation medium layer and the top surfaces of the number of first thermocouple parts, form a number of second thermocouple parts on the second isolation medium layer that are arranged in one-to-one correspondence with each first thermocouple part, connect the first ends of the relatively arranged first thermocouple parts and the first ends of the second thermocouple parts to obtain a number of thermocouples, and connect the number of thermocouples in series; S3: Form a third isolation medium layer covering the top surface of the second isolation medium layer and the top surfaces of the number of thermocouples, form a heat transfer structure on the third isolation medium layer, and the first isolation medium layer, the second isolation medium layer, and the third isolation medium layer constitute an isolation medium layer covering the top surface of the substrate; S4: Form a sacrificial layer covering the top surface of the isolation medium layer, form a heat collection structure on the sacrificial layer, and connect the heat collection structure to the heat transfer structure; S5: Form a cavity structure at the bottom of the substrate, and make the cavity structure opposite to the number of thermocouples; S6: Remove the sacrificial layer.

Images