CN114122245A

CN114122245A - Method for manufacturing thermopile sensor

Info

Publication number: CN114122245A
Application number: CN202111447387.1A
Authority: CN
Inventors: 陈达; 刘孟彬
Original assignee: Ningbo Semiconductor International Corp
Current assignee: Ningbo Semiconductor International Corp
Priority date: 2021-11-30
Filing date: 2021-11-30
Publication date: 2022-03-01

Abstract

A method of making a thermopile sensor, comprising: providing a thermopile structure plate, wherein the thermopile structure plate of the heat radiation induction area comprises a stacked functional layer and a substrate layer, and a thermopile structure is formed in the functional layer of the heat radiation induction area; forming a blind hole penetrating through the functional layer with partial thickness of the thermal radiation induction area on the surface of the functional layer on the side opposite to the substrate layer; the bonding between the cover plate with the first cavity and the thermopile structure plate is realized, and the first cavity is opposite to the functional layer of the thermal radiation induction area and is communicated with the blind hole; forming a bottom communicating hole penetrating through the substrate layer above the blind hole by taking the functional layer exposed out of the blind hole as an etching stop layer; removing the residual functional layer positioned between the bottom communicating hole and the blind hole to form a communicating hole which is communicated with the first cavity; realize the bonding of base plate stratum basale, be formed with the second cavity between the stratum basale of base plate and heat radiation induction zone, and the second cavity is linked together with the intercommunicating pore. The embodiment of the invention is beneficial to improving the performance of the thermopile sensor.

Description

Method for manufacturing thermopile sensor

Technical Field

The embodiment of the invention relates to the technical field of sensor manufacturing, in particular to a manufacturing method of a thermopile sensor.

Background

The thermopile (thermal-pile) is an element capable of converting temperature difference and electric energy into each other, and is composed of two or more thermocouples connected in series, the thermoelectrical potentials output by the thermocouples are mutually superposed, and when the temperature difference occurs on two sides of the thermopile, current can be generated. The thermopile sensor can be configured with various lenses and filters, thereby realizing applications in various application scenes such as temperature measurement (forehead temperature gun, ear temperature gun, food temperature detection and the like), qualitative/quantitative analysis of gas components, intelligent household appliances, lamp switches, medical equipment and the like.

However, the performance of thermopile sensors remains to be improved.

Disclosure of Invention

The embodiment of the invention aims to provide a manufacturing method of a thermopile sensor, which optimizes the performance of the thermopile sensor.

In order to solve the above problem, an embodiment of the present invention provides a method for manufacturing a thermopile sensor, including: providing a thermopile structure plate, wherein the thermopile structure plate comprises a thermal radiation induction area, the thermopile structure plate of the thermal radiation induction area comprises a functional layer and a substrate layer which are stacked, and a thermopile structure is formed in the functional layer of the thermal radiation induction area; forming a blind hole penetrating through the functional layer with partial thickness of the thermal radiation induction area on the surface of the functional layer on the side opposite to the substrate layer; providing a cover plate with a first cavity; the cover plate is bonded with the thermopile structure plate, and the first cavity is arranged opposite to the functional layer of the thermal radiation induction area and communicated with the blind hole; forming a bottom communicating hole penetrating through the substrate layer above the blind hole by taking the functional layer exposed out of the blind hole as an etching stop layer; removing the residual functional layer between the bottom communication hole and the blind hole to form a top communication hole penetrating through the functional layer, wherein the top communication hole and the bottom communication hole are communicated to form a communication hole penetrating through the thermopile structure plate, and the communication hole is communicated with the first cavity; providing a substrate; and the base plate is bonded with the basal layer of the thermopile structure plate, a second cavity is formed between the base plate and the basal layer of the thermal radiation induction area, and the second cavity is communicated with the communication hole.

Compared with the prior art, the technical scheme of the embodiment of the invention has the following advantages:

according to the manufacturing method of the thermopile sensor, the blind hole penetrating through the partial thickness functional layer of the thermal radiation sensing area is formed on the surface of the functional layer, which is opposite to the side of the substrate layer, so that after the cover plate and the thermopile structure plate are bonded, the residual functional layer on the top of the blind hole can be used as an etching stop layer to form the bottom communicating hole penetrating through the substrate layer above the blind hole, and accordingly, the first cavity is not exposed in a process environment for forming the bottom communicating hole, and the cover plate exposed out of the first cavity is prevented from being damaged by the process for forming the bottom communicating hole; after the bottom communicating hole is formed, removing the residual functional layer between the bottom communicating hole and the blind hole to form a communicating hole penetrating through the thermopile structure plate, wherein the functional layer only has partial thickness between the bottom communicating hole and the blind hole, so that the process difficulty for removing the functional layer between the bottom communicating hole and the blind hole is reduced, the required process time is short, and the residual functional layer at the top of the blind hole and the cover plate generally have higher etching selection ratio, thereby being beneficial to reducing the probability of damage of the process for removing the functional layer between the bottom communicating hole and the blind hole to the cover plate exposed from the first cavity; in summary, the embodiment of the invention reduces the damage probability of the cover plate, thereby reducing the scattering and reflection of infrared rays when the device works through the cover plate, further improving the transmittance of the infrared rays and optimizing the performance of the thermopile sensor.

Drawings

FIGS. 1-3 are schematic diagrams of corresponding steps in a method for fabricating a thermopile sensor;

fig. 4 to 15 are schematic structural diagrams corresponding to steps in an embodiment of a method for manufacturing a thermopile sensor according to the present invention.

Detailed Description

As is known in the art, the performance of thermopile sensors currently needs to be improved. The reason why the performance of the thermopile sensor needs to be improved is analyzed in combination with a method for manufacturing the thermopile sensor.

Fig. 1 to 3 are schematic structural diagrams corresponding to steps in a method for manufacturing a thermopile sensor.

Referring to fig. 1, providing a thermopile structure plate 1, wherein the thermopile structure plate 1 includes a heat radiation sensing region 1A, the thermopile structure plate 1 of the heat radiation sensing region 1A includes a functional layer 11 and a substrate layer 12 which are stacked, and a thermopile structure (not shown) is formed in the functional layer 11 of the heat radiation sensing region 1A; a top via hole 13 penetrating the functional layer 11 of the heat radiation sensitive area 1A is formed.

With continued reference to fig. 1, a cover plate 2 having a first cavity 21 is provided; and the cover plate 2 is bonded with the thermopile structure plate 1, and the first cavity 21 is arranged opposite to the functional layer 11 of the heat radiation sensing area 1A and communicated with the top communicating hole 13.

Referring to fig. 2, a bottom communication hole 14 penetrating through the base layer 12 above the top communication hole 13 is formed, the top communication hole 13 and the bottom communication hole 14 communicate to constitute a communication hole 15 penetrating through the thermopile structure plate 1, and the communication hole 15 communicates with the first cavity 21.

Referring to fig. 3, a substrate 3 is provided; and the substrate 3 is bonded with the substrate layer 12 of the thermopile structure plate 1, a second cavity 31 is formed between the substrate 3 and the substrate layer 12 of the heat radiation sensing region 1A, and the second cavity 31 is communicated with the communication hole 15.

In the manufacturing method of the thermopile sensor, before the bonding of the cover plate 2 and the thermopile structure plate 1 is realized, a top communicating hole 13 penetrating the functional layer 11 of the heat radiation sensing area 1A is formed; after the cover plate 2 and the thermopile structure plate 1 are bonded, a bottom communication hole 14 penetrating through the base layer 12 above the top communication hole 13 is formed, the top communication hole 13 and the bottom communication hole 14 are communicated to form a communication hole 15 penetrating through the thermopile structure plate 1, the communication hole 15 is communicated with the first cavity 21, wherein in the step of forming the bottom communication hole 14, as the first cavity 21 is communicated with the top communication hole 13, the cover plate 2 exposed by the first cavity 21 is easily damaged, the probability of scattering and reflection when infrared rays pass through the cover plate 2 is easily increased when the cover plate 2 is damaged, and further, the infrared ray transmittance is easily influenced, so that the performance of the thermopile sensor is poor.

In order to solve the technical problem, an embodiment of the present invention provides a method for manufacturing a thermopile sensor, including: providing a thermopile structure plate, wherein the thermopile structure plate comprises a thermal radiation induction area, the thermopile structure plate of the thermal radiation induction area comprises a functional layer and a substrate layer which are stacked, and a thermopile structure is formed in the functional layer of the thermal radiation induction area; forming a blind hole penetrating through the functional layer with partial thickness of the thermal radiation induction area on the surface of the functional layer on the side opposite to the substrate layer; providing a cover plate with a first cavity; the cover plate is bonded with the thermopile structure plate, and the first cavity is arranged opposite to the functional layer of the thermal radiation induction area and communicated with the blind hole; forming a bottom communicating hole penetrating through the substrate layer above the blind hole by taking the functional layer exposed out of the blind hole as an etching stop layer; removing the residual functional layer between the bottom communication hole and the blind hole to form a top communication hole penetrating through the functional layer, wherein the top communication hole and the bottom communication hole are communicated to form a communication hole penetrating through the thermopile structure plate, and the communication hole is communicated with the first cavity; providing a substrate; and the base plate is bonded with the basal layer of the thermopile structure plate, a second cavity is formed between the base plate and the basal layer of the thermal radiation induction area, and the second cavity is communicated with the communication hole.

In the manufacturing method of the thermopile sensor provided by the embodiment of the invention, the blind hole penetrating through the functional layer with partial thickness of the thermal radiation sensing area is formed on the surface of the functional layer on the side opposite to the substrate layer, so that after the bonding of the cover plate and the thermopile structure plate is realized, the residual functional layer on the top of the blind hole can be used as an etching stop layer to form a bottom communicating hole penetrating through the substrate layer above the blind hole, and accordingly, the first cavity is not exposed in the process environment for forming the bottom communicating hole, and the process for forming the bottom communicating hole is prevented from damaging the cover plate exposed from the first cavity; after the bottom communicating hole is formed, removing the residual functional layer between the bottom communicating hole and the blind hole to form a communicating hole penetrating through the thermopile structure plate, wherein the functional layer only has partial thickness between the bottom communicating hole and the blind hole, so that the process difficulty for removing the functional layer between the bottom communicating hole and the blind hole is reduced, the required process time is short, and the residual functional layer at the top of the blind hole and the cover plate generally have higher etching selection ratio, thereby being beneficial to reducing the probability of damage of the process for removing the functional layer between the bottom communicating hole and the blind hole to the cover plate exposed from the first cavity; in summary, the embodiment of the invention reduces the damage probability of the cover plate, thereby reducing the scattering and reflection of infrared rays when the device works through the cover plate, further improving the transmittance of the infrared rays and optimizing the performance of the thermopile sensor.

In order to make the aforementioned objects, features and advantages of the embodiments of the present invention comprehensible, specific embodiments accompanied with figures are described in detail below.

Referring to fig. 4, a thermopile structure plate 20 is provided, the thermopile structure plate 20 including a heat radiation sensing region 20A, the thermopile structure plate 20 of the heat radiation sensing region 20A including a functional layer 210 and a base layer 200 stacked, the functional layer 210 of the heat radiation sensing region 20A having a thermopile structure (not shown) formed therein.

The thermopile structure plate 20 serves as a sensing structure for receiving thermal radiation, thereby sensing temperature information.

In this embodiment, the distribution region of the thermopile structure is a heat radiation sensing region 20A, and the region around the heat radiation sensing region 20A is used for the subsequent fabrication of the interconnection conductive structure.

The base layer 200 is used to provide a process platform for the formation of the thermopile structure.

The functional layer 210 of the thermal radiation sensing region 20A includes an insulating layer 201 in contact with the substrate layer 200 and a functional structure layer 202 on a surface of the insulating layer 201 facing away from the substrate layer 200, and the thermopile structure is located in the functional structure layer 202.

The insulating layer 201 is used to electrically isolate the functional structure layer 202 from the substrate layer 200.

The functional structure layer 202 is used to form a thermopile structure.

Specifically, in this embodiment, the thermopile structure plate 200 includes a silicon-on-insulator substrate, the base layer 200 is a bottom semiconductor layer, and the functional structure layer 202 is a top semiconductor layer.

In this embodiment, the material of the base layer 200 may be an undoped semiconductor material (e.g., polysilicon or monocrystalline silicon); the material of the insulating layer 201 is an insulating material, for example: one or more of silicon oxide, silicon nitride, and silicon oxynitride; the material of the functional structure layer 202 may be an undoped semiconductor material (e.g., polysilicon or monocrystalline silicon), an N-type doped semiconductor material, or a P-type doped semiconductor material, and the formation process of the top semiconductor layer 202 includes an epitaxial process or an ion implantation process.

As an example, the material of the substrate layer 200 and the functional structure layer 202 is monocrystalline silicon, and the material of the insulating layer 201 is silicon oxide.

In other embodiments, the thermopile structure plate may not be a silicon-on-insulator substrate, and the thermopile structure includes a semiconductor substrate, an insulating layer on the semiconductor substrate, and the functional structure layer on the insulating layer. The semiconductor substrate is used as the base layer. The insulating layer may be a Shallow Trench Isolation (STI) structure or a Local Oxidation of Silicon (LOCOS) structure.

The thermopile structure includes at least one heat-sensing microstructure, which may be formed of any suitable thermally conductive material, for example, the material of the heat-sensing microstructure includes at least one of a metal, an undoped semiconductor material, a doped semiconductor material, and a metal silicide. The undoped semiconductor material or the doped semiconductor material each comprises one or more of silicon, germanium, gallium arsenide, and indium phosphide, and the doped semiconductor material has doping ions comprising N-type ions (e.g., arsenic, germanium, etc.) or P-type ions (e.g., boron fluoride, phosphorus, etc.).

In this embodiment, a partial region of the functional structure layer 202 is doped with N-type ions to form an N-type doped region, a partial region of the functional structure layer 202 is doped with P-type ions to form a P-type doped region, and the N-type doped region and the P-type doped region are used as a thermopile structure.

Specifically, the step of forming the thermopile structure includes: providing a functional structure layer 202; and performing at least one of N-type ion doping and P-type ion doping on a partial region of the functional structure layer 202 to form at least one of an N-type doped region and a P-type doped region as the thermopile structure.

The thermal sensing microstructure in the thermopile structure includes an N-type doped region and a P-type doped region formed in the functional structure layer 202, so that the fabrication of the thermopile structure is compatible with the CMOS process, thereby simplifying the process and reducing the cost.

Correspondingly, the N-type doped region is used as a first heat induction microstructure, the P-type doped region is used as a second heat induction microstructure, the thermopile structure comprises a first heat induction microstructure and a second heat induction microstructure which are made of different materials, the first heat induction microstructure is N-type doped monocrystalline silicon, and the second heat induction microstructure is P-type doped monocrystalline silicon.

The thermopile structure is not limited to a structure formed by doping, and may be another structure formed by another method.

The first heat-sensitive microstructure and the second heat-sensitive microstructure may be linear (e.g., linear, curved, or polygonal), array, or comb.

The first heat-sensing microstructure and the second heat-sensing microstructure can have approximately symmetrical structures, for example, when the first heat-sensing microstructure and the second heat-sensing microstructure are both linear structures, the first heat-sensing microstructure and the second heat-sensing microstructure have approximately the same length, which is beneficial to generating approximately symmetrical heat-sensing effect between the first heat-sensing microstructure and the second heat-sensing microstructure, and thus, the measurement accuracy of the thermopile sensor is beneficial to being improved.

Furthermore, the overall distribution of the first and second heat-sensitive microstructures may be juxtaposed in the plane of the thermopile structure plate 20 without overlap, or with partial regions nested, so as to be at least partially overlapping. As an example, the overall distribution area of the first thermal sensing microstructure and the overall distribution area of the second thermal sensing microstructure partially overlap in the plane of the thermopile structure plate 20, for example, the first thermal sensing microstructure and the second thermal sensing microstructure are both comb-shaped structures, and a part of comb teeth of the first thermal sensing microstructure are inserted into corresponding comb tooth gaps of the second thermal sensing microstructure, so that the thermopile sensor performance can be further improved without increasing the surface area of the thermopile sensor.

It should be noted that the materials of the first and second thermally induced microstructures are not limited to doped semiconductor materials. In other embodiments, the corresponding thermal-induced microstructures may also be formed on the semiconductor substrate by at least one of patterned etching of the metal layer, patterned etching of the semiconductor layer, and silicidation of the semiconductor layer. Correspondingly, the material of the heat-sensitive microstructure may also be at least one of a metal, an undoped semiconductor material, a metal silicide, and the like.

In other embodiments, the thermopile structure may have only one heat-sensitive microstructure, or at least three heat-sensitive microstructures of different materials, different structures, or both different materials and different structures, thereby forming different heat-sensitive microstructures. The material of the heat-sensitive microstructure comprises at least one of a metal, an undoped semiconductor material, a doped semiconductor material and a metal silicide; the undoped semiconductor material or the doped semiconductor material includes at least one of silicon, germanium, gallium arsenide, and indium phosphide, and the doped semiconductor material includes N-type ions or P-type ions.

In this embodiment, a conductive interconnection structure 300 is further formed on a surface of the functional layer 210 facing away from the substrate layer 200, and the conductive interconnection structure 300 is located in a peripheral region of the heat radiation sensing region 20A.

Specifically, the conductive interconnect structure 300 is electrically connected to the thermopile structure, and the conductive interconnect structure 300 is used to electrically connect the thermopile structure to an external circuit.

In this embodiment, the conductive interconnect structure 300 includes a PAD (PAD). As an example, the material of the conductive interconnect structure 300 includes aluminum.

In this embodiment, a passivation layer (not shown) is further formed on the surface of the conductive interconnect structure 300. The material of the passivation layer may include at least one of silicon dioxide, silicon nitride, and a low-k dielectric material.

Referring to fig. 5, blind holes 220 are formed through a part of the thickness of the functional layer 210 of the thermal radiation sensing region 20A on the surface of the functional layer 210 facing away from the base layer 200.

The blind hole 220 is used for the subsequent formation of a top communication hole.

By forming the blind hole 220 penetrating through a part of the thickness functional layer of the thermal radiation sensing area 20A, after the subsequent bonding of the cover plate with the first cavity and the thermopile structure plate 20 is realized, the bottom communication hole penetrating through the substrate layer 200 above the blind hole 220 can be formed by using the residual functional layer 210 at the top of the blind hole 220 as an etching stop layer, accordingly, the first cavity is not exposed in the process environment for forming the bottom communication hole, and the process for forming the bottom communication hole is prevented from damaging the cover plate exposed from the first cavity.

In this embodiment, the blind hole 220 penetrates through the functional structure layer 210, or the blind hole 220 penetrates through the functional structure layer 210 and a part of the thickness of the insulating layer 201.

The blind hole 220 at least penetrates through the functional structure layer 210, so that only the residual insulating layer 201 exposed from the blind hole 220 needs to be etched in the subsequent process of forming the top communicating hole, the process time for etching the insulating layer 210 to form the top communicating hole is favorably shortened, the functional structure layer 210 does not need to be etched, and the functional structure layer 210 is favorably prevented from being damaged in the process of forming the top communicating hole.

It should be noted that, in the step of forming the blind via 220, the thickness of the remaining functional layer 210 at the bottom of the blind via 220 is not too small, and is not too large.

In the subsequent process of forming the bottom communicating hole, a vacuum environment is present in a space where the first cavity and the blind hole 220 are connected, if the thickness of the remaining functional layer 210 at the bottom of the blind hole 220 is too small, the mechanical strength of the remaining functional layer 210 exposed by the blind hole 220 is easily reduced, so that the remaining functional layer 210 is easily broken in the subsequent process of forming the bottom communicating hole, and further the vacuum environment of the first cavity is difficult to ensure, and moreover, the risk that the remaining functional layer 210 exposed by the blind hole 220 is etched in the subsequent process of forming the bottom communicating hole is high, and the effect that the remaining functional layer 210 exposed by the blind hole 220 is used as an etching stop layer is easily reduced.

If the thickness of the remaining functional layer 210 at the bottom of the blind via 220 is too large, the process time required for subsequently etching the remaining functional layer 210 exposed by the blind via 220 is easily long, and further, the risk of damage to the functional structure layer 210 is easily increased.

As an embodiment, the thickness of the remaining functional layer 210 at the bottom of the blind via 220 is

To

For example: the remaining functional layer 210 at the bottom of the blind via 220 has a thickness of

In this embodiment, the process of forming the blind via 220 includes a dry etching process. Specifically, a patterned layer is formed on the functional layer 210; and etching the functional layer 210 by using the patterning layer as a mask and adopting a dry etching process to form the blind hole 220. The dry etching process has high etching precision and etching profile controllability, and is favorable for accurately controlling the depth and the opening size of the blind hole 220.

The number of the blind holes 220 is one or more. In this embodiment, the number of the blind holes 220 is plural.

It should be noted that the blind holes 220 are located in the thermal radiation sensing region 20A, the region between the thermopile structures, so as to prevent damage to the thermopile structures, thereby ensuring the integrity of the thermopile structures.

With continued reference to fig. 5, in this embodiment, the method for manufacturing a thermopile sensor further includes: after the formation of the blind hole 220, a first bonding ring 230(bonding ring) is formed on the functional layer 210 at a peripheral region of the heat radiation sensing area 20A.

The first bonding ring 230 is used for bonding with a second bonding ring formed on the cover plate, so as to bond the thermopile structure plate 20 with the cover plate, and is also used for sealing the first cavity after being bonded with the second bonding ring.

The first bonding ring 230 is a ring structure surrounding the heat radiation sensing region 20A. The first key ring 230 protrudes from the functional layer 210.

In this embodiment, the first bonding ring 230 is located between the heat radiation sensing region 20A and the conductive interconnection structure 300.

In this embodiment, the first bonding ring 230 is a metal bonding layer, and the material of the first bonding ring 230 is metal.

As an example, the first bonding ring 230 includes a metal layer 22 and a solder layer 23 on the metal layer 22. In this embodiment, the material of the metal layer includes one or both of copper and titanium, and the material of the solder layer 23 includes tin.

As an example, the step of forming the first keying ring 230 includes: forming a seed layer (not shown) on the functional layer 210; forming a patterned layer (not shown) on the seed layer, the patterned layer having an annular opening (not shown) formed therein around the heat radiation sensing region 20A; forming the first bonding ring 230 in the annular opening by an electroplating process; the exposed seed layer of the patterned layer and the first bonding ring 230 is removed.

The patterned layer is used to provide support for forming the first keyed ring 230 and also to define the pattern and dimensions of the first keyed ring 230. The annular opening is used to provide a spatial location for filling the first keyed ring 230.

As an example, the material of the patterned layer is photoresist.

In this embodiment, in the step of forming the first bonding ring 230, a first sealing layer 235 is further formed on an edge region of the functional layer 210. The first sealing layer 235 serves to seal the internal structure during subsequent processing, thereby protecting the internal structure from the external environment.

Specifically, the first sealing layer 235 is located at a peripheral region of the conductive interconnect structure 300. In this embodiment, the first sealing layer 235 also has a ring structure.

In this embodiment, the material of the first sealing layer 235 is the same as the material of the first bonding ring 230.

In this embodiment, after the first bonding ring 230 is formed, the method for manufacturing the thermopile sensor further includes: the passivation layer on the conductive interconnect structure 300 is removed to expose the conductive interconnect structure 300. The conductive interconnection structure 300 is exposed so that the electrical connection between the conductive interconnection structure 300 and an external circuit is subsequently achieved.

Referring to fig. 6, a cover plate 70 having a first cavity 701 is provided.

Subsequently, the cover plate 70 is bonded to the thermopile structure plate 20. The arrangement of the first cavity 701 can reduce the direct absorption of the incident thermal radiation by the upper layer structure as much as possible, and simultaneously store the incident thermal radiation to a certain extent, so that the thermopile structure receives the incident radiation heat to the maximum extent, and the performance of the thermopile sensor can be improved.

A radiation penetration window (not shown) is further disposed on the cover plate 70 at a side of the first cavity 701 facing away from the thermopile structure plate 20, the radiation penetration window is at least vertically aligned with the thermopile structure, and a material of the radiation penetration window includes a semiconductor (e.g., silicon, germanium, silicon-on-insulator, etc.) and/or an organic filter material (e.g., polyethylene, polypropylene, etc.).

The material of the cover plate 70 may be any suitable material known to those skilled in the art, such as glass, plastic, semiconductor, etc.

In this embodiment, a second key ring 702 is further formed on the cover plate 70 in the peripheral region of the first cavity 701. The second bonding ring 702 is used for subsequent bonding with the first bonding ring, thereby achieving bonding between the thermopile structure plate 20 and the cover plate 70 and sealing the first cavity 701.

In this embodiment, the second bonding ring 702 is a metal bonding layer, and the material of the second bonding ring 702 is metal.

As an example, the second bonding ring 702 includes a metal layer (not labeled) and a solder layer (not labeled) on the metal layer. In this embodiment, the material of the metal layer includes one or both of copper and titanium, and the material of the solder layer includes tin.

For a detailed description of the structure and materials of the second key ring 702, please refer to the corresponding description of the first key ring 230, which is not repeated herein.

In this embodiment, the cover plate 70 has an annular groove (not labeled) surrounding the first cavity 701; the second key ring 702 is formed in the annular recess.

In this embodiment, the annular groove serves as a spill-proof ring (sealing ring) to prevent the plating solution from spilling out during the formation of the second bonding ring 702.

In this embodiment, in the step of forming the second key ring 702, a second sealing layer 703 is further formed on an edge region of the cap plate 70. The second sealing layer 703 is used for subsequent bonding with the first sealing layer 235, thereby sealing the internal structure during subsequent processing, and further preventing the external environment from affecting the internal structure.

Specifically, the second sealing layer 703 is located at the peripheral region of the second key ring 702. In this embodiment, the second sealing layer 703 also has a ring structure.

In this embodiment, the material of the second sealing layer 703 is the same as the material of the second bonding ring 702.

In other embodiments, the first bonding ring may not be formed on the thermopile structure plate, and the second bonding ring may not be formed on the cover plate. The cover plate may include a cover plate base and a cavity wall on the cover plate base, the cavity wall enclosing the first cavity.

Accordingly, the step of forming the cap plate may include: providing a cover plate substrate; depositing a cavity material layer on the cover plate substrate; and etching the cavity material layer until the surface of the cover plate substrate is exposed, forming a second cavity in the cavity material layer, and forming a cavity wall by the residual cavity material. Accordingly, the bonding between the cover plate and the thermopile structure plate can be achieved subsequently by bonding the cavity wall with the thermopile structure plate.

Referring to fig. 7, the cover plate 70 is bonded to the thermopile structure plate 20, and the first cavity 701 is disposed opposite to the functional layer 210 of the thermal radiation sensing region 20A and is communicated with the blind hole 220.

Specifically, the step of bonding the cover plate 70 and the thermopile structure plate 20 includes: the bonding between the first bonding ring 230 and the second bonding ring 702 is achieved, and the first bonding ring 230 and the second bonding ring 702 seal the first cavity 701.

The first bonding ring 230 and the second bonding ring 702 seal the first cavity 701, and the first cavity 701 is communicated with the blind hole 220, so that a vacuum environment is ensured in the first cavity 701.

Accordingly, the first bonding ring 230 and the second bonding ring 702 are aligned and bonded in the vertical position, which is beneficial to preventing the problem of splintering caused by stress during the bonding process. Specifically, the bonding of the first bonding ring 230 and the second bonding ring 702 is achieved through a metal bonding process.

In this embodiment, in the step of achieving the bonding between the first bonding ring 230 and the second bonding ring 702, the first bonding ring 230 and the second bonding ring 702 are located between the heat radiation sensing region 20A and the conductive interconnection structure 300.

In this embodiment, in the step of bonding the first bonding ring 230 and the second bonding ring 702, the first sealing layer 235 and the second sealing layer 703 are aligned and bonded in an up-down position, so as to seal the heat radiation sensing region 20A, the first bonding ring 230 and the second bonding ring 702, and the conductive interconnection structure 300, and prevent the internal environment from being affected by the subsequent processes.

Referring to fig. 8 in combination, in this embodiment, the method for manufacturing the thermopile sensor further includes: after the cover plate 70 and the thermopile structure plate 20 are bonded, the surface of the base layer 200 facing away from the functional layer 210 is thinned.

The surface of the substrate layer 200, which is opposite to the functional layer 210 side, is thinned, so that the thickness of the thermopile structure plate 20 is reduced, thinning of the thermopile sensor is facilitated, the thickness of the substrate layer 200 is also reduced, in the subsequent process of forming the bottom communicating hole penetrating through the substrate layer 200 above the blind hole 220, the thickness of the substrate layer 200, which needs to be etched, for forming the bottom communicating hole is correspondingly reduced, the process difficulty for forming the bottom communicating hole is reduced, the process time for forming the bottom communicating hole is shortened, and the probability of damage of the formed bottom communicating hole to other film layer structures is reduced.

As an example, the substrate layer 200 is thinned by an etching process. Specifically, the base layer 200 is thinned by a wet etching process. In other embodiments, the base layer may be thinned by a dry etching process.

In other embodiments, the substrate layer may be thinned by a grinding process or a process combining a grinding process and an etching process.

Referring to fig. 9, in this embodiment, the method for manufacturing a thermopile sensor further includes: after the bonding of the cover plate 70 to the thermopile structure plate 20 is achieved, a third bonding ring 203 surrounding the heat radiation sensing region 20A is formed on the surface of the substrate layer 200 on the side facing away from the functional layer 210.

Specifically, after the surface of the substrate layer 200 facing away from the functional layer 210 is thinned, the third bond ring 203 is formed.

The third bonding ring 203 is used for being bonded with a fourth bonding ring formed on the substrate subsequently to realize bonding between the thermopile structure plate 20 and the subsequent substrate, and is also used for sealing a second cavity formed between the thermopile structure plate 20 and the substrate after being bonded with the fourth bonding ring.

The third bond ring 203 is a ring structure surrounding the heat radiation sensing region 20A. The third bond rings 203 protrude from the substrate layer 200.

As an example, the third bonding ring 203 includes a metal layer (not shown) and a solder layer (not shown) on the metal layer. In this embodiment, the material of the metal layer includes one or both of copper and titanium, and the material of the solder layer includes tin.

For a detailed description of the material and the structure of the third bond ring 203, please refer to the corresponding description of the first bond ring 230, which is not repeated herein.

In this embodiment, the line width of the third bonding ring 203 is greater than the line widths of the first bonding ring 230 and the second bonding ring 702, which is beneficial to increase the mechanical strength of the third bonding ring 203 in the subsequent process of implementing the bonding between the third bonding ring 203 and the fourth bonding ring, thereby reducing the probability of the substrate or the thermopile structure plate 20 breaking during the bonding process.

In one embodiment, the line width of the third bond ring 203 is greater than the total width of the first bond ring 230 and the conductive interconnect structure 300, so that during the subsequent process of exposing the conductive interconnect structure 300 to achieve the electrical connection between the conductive interconnect structure 300 and the external circuit (e.g., wire bonding process), the third bond ring 203 can support the conductive interconnect structure 300 to prevent the rupture of the thermopile structure plate.

In this embodiment, in the step of forming the third bonding ring 203, a third sealing layer 204 is further formed on an edge region of the substrate layer 200. Third sealing layer 204 is used to seal the internal structure during subsequent processing, thereby protecting the structure from the external environment.

Specifically, the third sealing layer 204 is located at a peripheral region of the third bonding ring 203. In this embodiment, the third sealing layer 204 also has a ring structure.

In this embodiment, the material of third sealing layer 204 is the same as the material of third sealing ring 203.

Referring to fig. 10, a bottom via 240 penetrating the base layer 200 above the blind via 220 is formed by using the functional layer 210 exposed by the blind via 220 as an etching stop layer.

The functional layer 210 exposed by the blind via 220 is used as an etching stop layer to form a bottom communication hole 240 penetrating through the substrate layer 200 above the blind via 220, accordingly, the first cavity 701 and the bottom communication hole 240 are sealed by the functional layer 210, the first cavity 701 is not exposed in a process environment for forming the bottom communication hole 240, damage to the cover plate 70 exposed by the first cavity 701 due to the process for forming the bottom communication hole 240 is prevented, and a vacuum environment of the first cavity 701 is ensured.

Specifically, the insulating layer 201 exposed by the blind via 220 is used as an etching stop layer, and the base layer 200 above the blind via 220 is etched to form the bottom via 220.

The material of the insulating layer 201 is different from that of the base layer 200, and an etching selection ratio is provided between the insulating layer 201 and the base layer 200, so that the insulating layer 201 can define the position where etching stops in the step of forming the bottom communication hole 220.

More specifically, in this embodiment, the material of the insulating layer 201 is silicon oxide, the material of the base layer 200 is silicon, and a high etching selectivity ratio is provided between silicon and silicon oxide, so as to improve an effect of the insulating layer 201 for defining an etching stop position.

In this embodiment, the process of forming the bottom via 220 includes a dry etching process. The dry etching process has high process controllability and is easy to realize high etching selection ratio.

Referring to fig. 11, the remaining functional layer 210 between the bottom via hole 240 and the blind hole 220 is removed, and a top via hole 250 penetrating the functional layer 210 is formed, the top via hole 250 and the bottom via hole 250 are communicated to form a via hole 260 penetrating the thermopile structure plate 20, and the via hole 260 is communicated with the first cavity 701.

In the process of forming the top via 250 penetrating through the functional layer 210, since the functional layer 210 only has a partial thickness between the bottom via 240 and the blind via 220, the difficulty of the process for removing the functional layer 210 between the bottom via 240 and the blind via 220 is reduced, the required process time is short, and a high etching selectivity ratio is usually provided between the residual functional layer 210 on the top of the blind via 220 and the cap plate 20, which is beneficial to reducing the possibility that the process for removing the functional layer 210 between the bottom via 240 and the blind via 220 damages the cap plate 70 exposed from the first cavity 701.

To sum up, this embodiment reduces the impaired probability of apron 70 to when the device work, can reduce the scattering and the reflection of infrared ray when passing apron 70, and then improve the infrared ray transmissivity, optimized the performance of thermopile sensor.

In this embodiment, the process of removing the remaining functional layer 210 located between the bottom via 240 and the blind via 220 includes a dry etching process. The dry etching process has high process controllability and is easy to realize a high etching selection ratio, thereby further reducing the probability of damage to the cover plate 70 exposed from the first cavity 701.

In other embodiments, based on the actual process, other etching processes may be used to remove the remaining functional layer between the bottom via and the blind via.

Referring to fig. 12, a substrate 10 is provided.

The substrate 10 is used to achieve bonding with the thermopile structure plate 20. Specifically, follow-up with thermopile structure board 20 bonding on base plate 10 to form the second cavity between thermopile structure board 20 and base plate 10, the bottom of base plate 10 sealed second cavity, thereby reduce the thermal loss in the second cavity, and then be favorable to improving the measurement accuracy of thermopile sensor.

The substrate 10 may be a carrier wafer (carrier wafer) or a circuit substrate, and the circuit substrate is a CMOS substrate that performs a FEOL (front end of line) process and a BEOL (back end of line) process and a wafer probe test, and a readout circuit structure is formed in the circuit substrate. The FEOL process and the BEOL process are both conventional process technologies for manufacturing CMOS integrated circuits in the art, and wafer probing is a conventional test scheme for testing performance of CMOS integrated circuits in the art, which is not described herein again.

As an example, the substrate 10 is a circuit substrate. After the thermopile structure plate 20 is bonded on the substrate 10, the substrate 10 is located below the thermopile structure plate 20, so that vertical system integration of the readout circuit structure can be realized without increasing the area, the interconnection length from a sensing signal to the readout circuit structure, signal loss and noise can be shortened, and the miniaturization of the thermopile sensor can be facilitated; in addition, it is beneficial to further extend to 3D system integration of fabricating active thermal imaging sensor arrays with CMOS readout pixel arrays and peripheral circuits.

The substrate 10 includes a base 100, electronic components formed in the base 100, and an interconnect layer (not shown) formed on the base 100, and the base 100 may be any suitable semiconductor substrate material known to those skilled in the art, such as silicon, silicon-on-insulator, germanium, silicon germanium, gallium arsenide, indium phosphide, and the like.

The substrate 100 has formed therein respective electronic elements formed by a CMOS manufacturing process, including at least one of a MOS transistor including a gate structure and source and drain regions in the substrate at both sides of the gate structure, a resistor, a diode, a capacitor, a memory, and the like, and an isolation structure between adjacent electronic elements. Wherein the MOS transistor may include at least one of a PMOS transistor and an NMOS transistor; the isolation structure may be formed by a local field oxidation process or a Shallow Trench Isolation (STI) process; the interconnect layer is formed by BEOL process and specifically includes an inter-metal dielectric (IMD) and a readout circuitry structure (not shown) located in the IMD, the readout circuitry structure being isolated by the IMD.

The reading circuit structure comprises a bottom contact plug which is directly electrically contacted with a corresponding terminal of an electronic element and a multilayer metal interconnection structure which is electrically connected with the bottom contact plug, wherein the multilayer metal interconnection structure comprises a plurality of metal interconnection layers which are sequentially stacked, the adjacent metal interconnection layers are isolated through metal interlayer dielectric layers, and the adjacent metal interconnection layers are electrically connected through a conductive through hole (via) structure positioned in the metal interlayer dielectric layers in a local area. The interconnect layer has openings therein that expose portions of the surface of the readout circuitry structure to form probing points for wafer probing.

In this embodiment, the method for manufacturing the thermopile sensor further includes: a fourth bond ring 102 is formed on the substrate 10. The fourth bonding ring 102 is used for bonding with the third bonding ring 203, so as to bond the substrate 10 and the thermopile structure plate 20.

The fourth bonding ring 102 is an annular structure, and an area enclosed by the fourth bonding ring 102 corresponds to the heat radiation reaction area 20A in the subsequent thermopile structure plate 20.

For a detailed description of the material and the structure of the fourth key ring 102, please refer to the corresponding description of the first key ring 230, which is not repeated herein.

In this embodiment, an anti-overflow ring is also formed on the substrate 10, and the anti-overflow ring is an annular groove for preventing the plating solution from overflowing during the process of forming the fourth bonding ring 102. The fourth key ring 102 is formed in an overflow preventing ring on the base plate 10.

It should be noted that, in the subsequent process of implementing the bonding between the substrate 10 and the thermopile structure plate 20, the fourth bonding ring 102 is aligned with the third bonding ring 203 and the bonding is implemented, so that the position of the fourth bonding ring 102 corresponds to the position of the third bonding ring 203, and the line width of the fourth bonding ring 102 is the same as the line width of the third bonding ring 203.

Accordingly, the line width of the fourth bonding ring 102 is greater than the line widths of the first bonding ring 230 and the second bonding ring 702, which is beneficial to increasing the mechanical strength and the bonding strength of the third bonding ring 203 and the fourth bonding ring 102 in the subsequent process of realizing the bonding between the third bonding ring 203 and the fourth bonding ring 102, and further reducing the probability of the substrate 10 or the thermopile structure plate 20 breaking in the bonding process.

In one embodiment, the line width of the fourth bonding ring 102 is greater than the total width of the first bonding ring 230 and the conductive interconnect structure 300, so that after the third bonding ring 203 and the fourth bonding ring 102 are implemented, the conductive interconnect structure 300 is subsequently exposed, and during an electrical connection process (e.g., a wire bonding process) between the conductive interconnect structure 300 and an external circuit, the fourth bonding ring 102 and the third bonding ring 203 can support the conductive interconnect structure 300, thereby preventing the thermopile structure board from being broken.

In this embodiment, in the step of forming the fourth bonding ring 102, a fourth sealing layer 104 is further formed on an edge region of the substrate 10. Fourth encapsulant layer 104 is configured to subsequently bond to third encapsulant layer 204 to seal the internal structure during subsequent processing to protect the structure from the external environment.

Specifically, the fourth sealing layer 104 is located at a peripheral region of the fourth bonding ring 102. In this embodiment, the fourth sealing layer 104 also has a ring structure.

In this embodiment, the material of the fourth sealing layer 104 is the same as the material of the fourth bonding ring 102.

In this embodiment, in the step of providing the substrate 10, a getter layer 103 is further formed on the substrate 10.

The getter layer 103 is used for adsorbing target gas molecules, so as to maintain a vacuum environment in the first cavity 701 and the second cavity, and further ensure that the first cavity 701 and the second cavity have a heat insulation function.

Referring to fig. 13, the substrate 10 is bonded to the base layer 200 of the thermopile structure plate 20, a second cavity 101 is formed between the substrate 10 and the base layer 200 of the heat radiation sensing region 20A, and the second cavity 101 communicates with the communication hole 260.

The second cavity 101 is aligned with the first cavity 701 up and down.

The second cavity 101 is communicated with the first cavity 701 through the communicating hole 260, so that heat energy is transferred between the hot end and the cold end in the thermopile structure through one path, the thermal resistance is increased, the effect of vacuum heat insulation of the second cavity 101 and the first cavity 701 is improved, and the performance of the thermopile sensor is improved.

In this embodiment, the step of bonding the substrate 10 and the thermopile structure plate 20 includes: bonding between the third bonding ring 203 and the fourth bonding ring 102 is achieved, and the third bonding ring 203 and the fourth bonding ring 102, the substrate 10 and the substrate layer 200 enclose the sealed second cavity 101.

In this embodiment, in the step of bonding third bonding ring 203 and fourth bonding ring 102, bonding between third sealing layer 204 and fourth sealing layer 104 is also achieved.

Accordingly, the bonding between third bonding ring 203 and fourth bonding ring 102, and the bonding between third encapsulant layer 204 and fourth encapsulant layer 104 are achieved by means of metal bonding.

In other embodiments, the second cavity may be formed between the substrate and the thermopile structure plate by other suitable methods based on the actual process.

In this embodiment, in the process of achieving the bonding between the substrate 10 and the thermopile structure plate 20, the getter layer 103 is located in the second cavity 101, so as to facilitate maintaining a vacuum insulation environment of the second cavity 101 and the first cavity 701.

Referring to fig. 14 in combination, in this embodiment, the method for manufacturing the thermopile sensor further includes: realize the base plate 10 with behind the bonding of thermopile structure board 20, it is right base plate 10 dorsad the surface of thermopile structure board 20 one side carries out the attenuate processing, and to apron 70 dorsad one side surface of thermopile structure board 20 carries out the attenuate processing.

And thinning the two sides, thereby reducing the thickness of the thermopile sensor. Wherein, it is right that one side surface of the apron 70 back to the thermopile structure board 20 carries out attenuate processing to reduce the thickness of apron 70, be favorable to the transmission of infrared ray in apron 70.

With continued reference to fig. 14, the method of fabricating the thermopile sensor further includes: an antireflection film 710 is formed on the surface of the cover plate 70 on the side facing away from the thermopile structure plate 20. The antireflection film 710 is used to increase the transmittance of infrared rays, thereby improving the performance of the thermopile sensor.

As an example, the material of the antireflection film 710 includes silicon oxide.

Specifically, after the surface of the substrate 10 facing away from the thermopile structure plate 20 is thinned and the surface of the cover plate 70 facing away from the thermopile structure plate 20 is thinned, an antireflection film 710 is formed on the surface of the cover plate 70 facing away from the thermopile structure plate 20.

Referring to fig. 15, after the bonding of the substrate 10 and the thermopile structure plate 20 is achieved, the method for manufacturing the thermopile sensor further includes: a portion of the cover plate 70 at the peripheral region of the heat radiation sensing region 20A is removed to expose the conductive interconnection structure 300. The conductive interconnect structure 300 is exposed to facilitate subsequent electrical connection between the conductive interconnect structure 300 and external circuitry.

In this embodiment, after the antireflection film 710 is formed on the surface of the cover plate 70 on the side facing away from the thermopile structure plate 20, a part of the cover plate 70 in the peripheral region of the heat radiation sensing region 20A is removed.

Specifically, the edge of the cover plate 70 is trimmed by a laser cutting process or the like, exposing the conductive interconnection structure 300.

In the method for manufacturing a thermopile sensor according to this embodiment, the blind hole 220 penetrating through the functional layer 210 with a partial thickness of the thermal radiation sensing region 20A is formed on the surface of the functional layer 210 facing away from the base layer 200, so that after the cover plate 70 and the thermopile structure plate 20 are bonded, the bottom via 250 penetrating through the base layer 200 above the blind hole can be formed by using the remaining functional layer 210 at the top of the blind hole 220 as an etching stop layer, and accordingly, the first cavity 701 is not exposed in the process environment for forming the bottom via 250, and the process for forming the bottom via 250 is prevented from damaging the cover plate 70 exposed by the first cavity 701.

Moreover, after the bottom communication hole 250 is formed, the residual functional layer 210 between the bottom communication hole 250 and the blind hole 220 is removed, and the communication hole 260 penetrating through the thermopile structure plate 20 is formed, because the functional layer 210 only has a partial thickness between the bottom communication hole 250 and the blind hole 220, the process difficulty of removing the functional layer 210 between the bottom communication hole 250 and the blind hole 220 is reduced, the required process time is short, and a higher etching selection ratio is usually provided between the residual functional layer 210 on the top of the blind hole 220 and the cover plate 70, which is beneficial to reducing the probability of damage to the cover plate 70 exposed from the first cavity 701 by the process of removing the functional layer 210 between the bottom communication hole 250 and the blind hole.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method of making a thermopile sensor, comprising:

providing a thermopile structure plate, wherein the thermopile structure plate comprises a thermal radiation induction area, the thermopile structure plate of the thermal radiation induction area comprises a functional layer and a substrate layer which are stacked, and a thermopile structure is formed in the functional layer of the thermal radiation induction area;

forming a blind hole penetrating through the functional layer with partial thickness of the thermal radiation induction area on the surface of the functional layer on the side opposite to the substrate layer;

providing a cover plate with a first cavity;

the cover plate is bonded with the thermopile structure plate, and the first cavity is arranged opposite to the functional layer of the thermal radiation induction area and communicated with the blind hole;

forming a bottom communicating hole penetrating through the substrate layer above the blind hole by taking the functional layer exposed out of the blind hole as an etching stop layer;

removing the residual functional layer between the bottom communication hole and the blind hole to form a top communication hole penetrating through the functional layer, wherein the top communication hole and the bottom communication hole are communicated to form a communication hole penetrating through the thermopile structure plate, and the communication hole is communicated with the first cavity;

providing a substrate;

and the base plate is bonded with the basal layer of the thermopile structure plate, a second cavity is formed between the base plate and the basal layer of the thermal radiation induction area, and the second cavity is communicated with the communication hole.

2. The method of making a thermopile sensor of claim 1, further comprising: and after the cover plate and the thermopile structure plate are bonded, thinning the surface of the substrate layer, which is opposite to the functional layer, before the bottom communicating hole is formed.

3. The method of manufacturing a thermopile sensor according to claim 1, wherein in the step of providing a thermopile structure plate, the functional layer of the thermal radiation sensing region includes an insulating layer in contact with the base layer and a functional structure layer on a surface of the insulating layer opposite to the base layer;

in the step of forming the blind hole, the blind hole penetrates through the functional structure layer, or the blind hole penetrates through the functional structure layer and the insulating layer with partial thickness;

and in the step of forming the bottom communicating hole, etching the substrate layer above the blind hole by taking the insulating layer exposed out of the blind hole as an etching stop layer to form the bottom communicating hole.

4. The method of manufacturing a thermopile sensor according to claim 1 or 3, wherein the method is carried out inIn the step of forming the blind hole, the thickness of the residual functional layer at the bottom of the blind hole is

To

5. The method of claim 3, wherein the thermopile structure plate comprises a silicon-on-insulator substrate, the base layer is a bottom semiconductor layer, and the functional structure layer is a top semiconductor layer.

6. The method of fabricating a thermopile sensor according to claim 1, wherein the process of forming the blind via comprises a dry etching process.

7. The method of making a thermopile sensor of claim 1, further comprising: after the blind holes are formed and before the cover plate is bonded with the thermopile structure plate, a first bonding ring is formed in the peripheral area of the heat radiation induction area on the functional layer;

in the step of providing the cover plate with the first cavity, a second key ring is further formed on the cover plate in the peripheral area of the first cavity;

the step of bonding the cover plate and the thermopile structure plate comprises the following steps: and realizing bonding between the first bonding ring and the second bonding ring, wherein the first bonding ring and the second bonding ring seal the first cavity.

8. The method according to claim 7, wherein in the step of providing a thermopile structure plate, a surface of the functional layer facing away from the base layer is further formed with an electrically conductive interconnection structure, and the electrically conductive interconnection structure is located in a peripheral region of the heat radiation sensing region;

in the step of forming the first bond ring, the first bond ring is located between the thermal radiation-sensitive region and the electrically conductive interconnect structure;

in the step of effecting bonding between the first and second bonding rings, the first and second bonding rings are located between the heat radiation sensing region and the conductive interconnect structure.

9. The method of claim 7, wherein the process of effecting bonding between the first bonding ring and the second bonding ring comprises a metal bonding process.

10. The method of fabricating a thermopile sensor according to claim 1, wherein the process of forming the bottom via hole comprises a dry etching process.

11. The method of fabricating a thermopile sensor according to claim 1, wherein the process of removing the remaining functional layer between the bottom via hole and the blind hole comprises a dry etching process.

12. The method of making a thermopile sensor of claim 1, further comprising: after the cover plate and the thermopile structure plate are bonded, before a bottom communication hole penetrating through the base layer above the blind hole is formed, a third bonding ring surrounding the heat radiation induction area is formed on the surface of one side, opposite to the functional layer, of the base layer;

the step of bonding the substrate and the thermopile structure plate comprises the following steps: forming a fourth bond ring on the substrate; and realizing the bonding between the third bonding ring and the fourth bonding ring, wherein the third bonding ring and the fourth bonding ring, the substrate and the substrate layer enclose the sealed second cavity.

13. The method of claim 12, wherein the functional layer has a first bonding ring formed on a peripheral region of the thermal radiation sensing area, and the first cavity has a second bonding ring formed on a cover plate of the peripheral area, and the bonding of the cover plate to the thermopile structure plate comprises: realizing the bonding of the first bonding ring and the second bonding ring, wherein the first bonding ring and the second bonding ring seal the first cavity;

in the step of forming the third bond ring and the fourth bond ring, line widths of the third bond ring and the fourth bond ring are greater than line widths of the first bond ring and the second bond ring.

14. The method of making a thermopile sensor of claim 1, further comprising: realize the base plate with behind the bonding of thermopile structural slab, it is right the base plate dorsad the attenuate processing is carried out on the surface of thermopile structural slab one side, and to the apron dorsad one side surface of thermopile structural slab carries out the attenuate processing.

15. The method for manufacturing a thermopile sensor according to claim 1, wherein in the step of providing a thermopile structure plate, a conductive interconnection structure is further formed on a surface of the functional layer facing away from the base layer, the conductive interconnection structure being located in a peripheral region of the heat radiation sensing region;

after the substrate is bonded with the thermopile structure plate, the manufacturing method of the thermopile sensor further comprises the following steps: and removing part of the cover plate in the peripheral area of the heat radiation sensing area to expose the conductive interconnection structure.

16. The method of fabricating a thermopile sensor according to claim 1, wherein in the step of providing a substrate, a getter layer is further formed on the substrate;

in the process of realizing the bonding of the substrate and the thermopile structure plate, the getter layer is positioned in the second cavity.