CN214200388U

CN214200388U - Infrared thermopile sensor

Info

Publication number: CN214200388U
Application number: CN202022364273.8U
Authority: CN
Inventors: 韩凤芹; 刘孟彬; 狄云翔
Original assignee: Smic Ningbo Co ltd Shanghai Branch
Current assignee: Smic Ningbo Co ltd Shanghai Branch; Ningbo Semiconductor International Corp Shanghai Branch
Priority date: 2020-07-17
Filing date: 2020-10-21
Publication date: 2021-09-14
Anticipated expiration: 2030-10-21

Abstract

The utility model provides an infrared thermopile sensor, include: a first substrate comprising a first region and a second region, the first substrate having opposing first and second surfaces; the first surface of the first region is provided with a thermopile structure; the first surface of the second area is provided with a thermistor structure. The embodiment of the utility model provides an infrared thermopile sensor thermopile structure and thermistor structure integration are on first base plate, and the integrated level is high, and is small, simple process.

Description

Infrared thermopile sensor

Technical Field

The utility model relates to a semiconductor manufacturing field especially relates to an infrared thermopile sensor.

Background

An infrared sensor (english name: transducer/sensor) is a detection device, which converts sensed information to corresponding signals according to a certain rule and outputs the signals, so as to detect the information. Typical infrared sensors such as temperature infrared sensors, pressure infrared sensors, optical infrared sensors, and the like not only promote the transformation and updating of the traditional industry, but also continuously develop novel industries, and become the focus of attention of people.

With the rapid development of micro-electro-mechanical systems (MEMS) technology, miniaturized infrared sensors fabricated based on MEMS micromachining technology are widely used in the fields of temperature measurement, gas sensing, optical imaging, etc. due to their advantages of small size and low price. In the process of the infrared sensor for temperature, the thermopile unit is adopted to receive radiation information to detect the temperature of a measured object, and meanwhile, in order to improve the accuracy, the thermistor unit is required to receive the current ambient temperature at the same time so as to improve the calculation accuracy.

However, the thermopile unit and the thermosensitive unit in the existing infrared thermopile sensor are separately designed and then reassembled, which is complex in process, large in volume and contrary to the trend of miniaturization. Therefore, it is desirable to provide an infrared thermopile sensor with simple process and small volume.

SUMMERY OF THE UTILITY MODEL

The utility model provides a problem how to reduce infrared thermopile sensor's device volume, simplify process flow.

In order to solve the above problem, the utility model provides an infrared thermopile sensor, include:

a first substrate comprising a first region and a second region, the first substrate having opposing first and second surfaces;

the first surface of the first region is provided with a thermopile structure;

the first surface of the second area is provided with a thermistor structure.

Compared with the prior art, the utility model discloses technical scheme has following advantage:

the utility model provides an among the infrared thermopile sensor, thermopile structure and thermistor structure all form on first base plate, can reduce the infrared thermopile sensor's of formation volume, improve the integrated level of device.

Furthermore, the thermistor structure is closer to the cold end of the thermopile structure, so that the obtained cold end temperature is more accurate, and the measurement precision of the infrared thermopile sensor can be improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic structural diagram illustrating a first substrate and a dielectric layer formed in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of forming a first electrode material layer on the dielectric layer in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a first electrode formed in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a passivation layer formed in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 5a is a schematic structural diagram of a second electrode and a thermistor structure formed in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 5b is a top view of the thermistor structure in fig. 5a in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of an absorption layer formed in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 7 is a schematic structural diagram of a protective layer formed in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 8 is a schematic structural diagram illustrating a thermal radiation isolation groove formed in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 9 is a schematic structural diagram illustrating a first interconnection structure, a second interconnection structure, a first connection structure, and a second connection structure formed in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 10 is a schematic structural diagram illustrating formation of a first cavity, a third interconnect structure and a fourth interconnect structure in a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 11 is a schematic structural diagram of an infrared thermopile sensor according to an embodiment of the present invention.

Fig. 12 is a schematic structural diagram of an infrared thermopile sensor according to yet another embodiment of the present invention.

Detailed Description

As is known in the art, the device size of the existing infrared thermopile sensor needs to be increased.

The infrared thermopile sensor is also called a thermopile infrared detector, and the traditional infrared thermopile sensor comprises a thermopile chip and a thermistor chip. The basic principle of temperature measurement of the infrared thermopile sensor is that infrared radiation energy of a human body is directly converted into a voltage signal which is continuously output through the thermopile chip, the thermistor chip forms a voltage division signal in a circuit, the voltage signal and the voltage division signal are subjected to signal processing, whether temperature difference caused by infrared radiation exists between the thermopile chip and the thermistor chip or not is calculated according to the voltage signal and the voltage division signal, and accuracy of the infrared thermopile sensor is improved. However, the thermopile chip and the thermistor chip in the infrared thermopile sensor are formed separately, and then the two are mounted on the package base and electrically connected with the signal processing chip through a wire.

Because the thermopile chip and the thermistor chip are formed respectively, the process steps are longer, and the thermopile chip and the thermistor chip are separately installed on the packaging base, so that the size is larger, and meanwhile, the reliability is poorer due to the connection of an external lead.

In order to solve the above problem, an embodiment of the present invention provides a method for manufacturing an infrared thermopile sensor, including:

providing a first substrate comprising a first region and a second region, the first substrate having opposing first and second surfaces;

forming a thermopile structure on the first region first surface;

and forming a thermistor structure on the first surface of the second area.

The embodiment of the utility model provides an among the manufacturing method of infrared thermopile sensor, thermopile structure and thermistor structure all form on first base plate, and the two distance can be nearer, has reduced the volume of the infrared thermopile sensor who forms.

The thermopile structure and the thermistor structure can be formed by a semiconductor process, and the compatibility is good.

The thermistor structure is formed in the process of forming the thermoelectric stack structure, so that the processes of respectively forming and assembling the thermistor structure and the thermistor structure are omitted, and the process flow is simple.

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Referring to fig. 1 to 11, fig. 1 to 11 are schematic structural diagrams corresponding to steps in a manufacturing method of an infrared thermopile sensor according to an embodiment of the present invention.

As shown in fig. 1, a first substrate 200 is provided; the first substrate includes a first region I and a second region II.

The second zone II surrounds the first zone I.

In one embodiment, the first substrate includes: a plurality of first zones I and a plurality of second zones II surrounding the first zones I.

The first substrate 200 may be any suitable substrate material known to those skilled in the art, such as a bulk semiconductor substrate material, e.g., silicon, germanium, silicon germanium, gallium arsenide, indium phosphide, etc.

The first substrate 200 has a first surface and a second surface opposite to each other.

In this embodiment, a dielectric layer 201 is further formed on the first substrate 200. The dielectric layer 201 is located on the first surface of the first substrate 200.

The dielectric layer 201 is used for isolating a thermopile structure formed subsequently from a first substrate, and is also used as a support layer of the thermopile structure.

The material of the dielectric layer 201 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride.

The dielectric layer 201 is formed by a deposition process or a thermal oxidation process.

As shown in fig. 2 to 7, a thermopile structure is formed on the first surface of the first region I; and forming a thermistor structure on the first surface of the second area II.

The thermopile structure includes: comprises an infrared radiation area and a peripheral area; the thermal radiation isolation groove exposes out of the thermopile structure of the infrared radiation area.

The thermopile structure includes a plurality of interconnected thermocouple pairs, each thermocouple pair including first and second electrodes electrically connected to each other, the first and second electrodes each extending from a peripheral region to an infrared radiation region.

The hot end of the thermocouple pair is located in the infrared radiation region, and the cold end of the thermocouple pair is located in the peripheral region.

The thermistor structure includes: a single layer film structure or a multi-layer film structure.

When the thermistor structure is a multilayer film structure, the materials of all the film layers can be the same or different, or the doping concentrations of all the film layers are the same or different.

The thermistor structure is at least a two-layer structure; and respectively forming two film layers of the thermistor structure when the first electrode is formed and the second electrode is formed.

The thermistor structure is a linear strip in S-shaped arrangement or spiral arrangement.

The material of the thermistor structure is the same as that of one electrode of the thermopile structure; or the material of the thermistor structure is the same as that of two electrodes of the thermopile structure.

That is, the material of the thermistor structure is the same as the material of the first electrode, or the second electrode.

The material of the thermistor structure can be a material with a negative temperature coefficient, and can also be a material with a positive temperature coefficient.

The thermistor structure is made of materials including: one, two or more than two metals or metal oxides of aluminum, copper, nickel, chromium, iron, titanium, gold, silver, platinum, manganese, cobalt, zinc and the like; or a layer of semiconductor material; or a semiconductor layer containing heavy metal doping, wherein the heavy metal doping ions are: one or more of aluminum, copper, gold, platinum, silver, nickel, iron, manganese, molybdenum, tungsten, titanium, zinc, mercury, cadmium, chromium, and vanadium.

The material of the semiconductor material layer comprises: and the semiconductor material can be in a single crystal state, a polycrystal state or an amorphous state.

In this embodiment, the thermistor structure is made of aluminum metal.

The forming method of each film layer of the thermistor structure comprises the following steps: depositing a thermosensitive material layer, and patterning the thermosensitive material layer to form a thermosensitive resistance film layer of the thermosensitive material layer; or depositing a dielectric layer, patterning the dielectric layer to form a groove, and forming each film layer of the thermistor structure in the groove.

The forming method of the thermopile structure comprises the following steps: forming a first electrode material layer on the first substrate; patterning the first electrode material layer to form a plurality of discrete first electrodes; forming a second electrode material layer on the first substrate and the first electrode; and patterning the second electrode material layer to form a plurality of discrete second electrodes, wherein the first electrodes are connected with the second electrodes.

After forming the thermopile structure, forming the thermistor structure; or after the thermistor structure is formed, the thermopile structure is formed; alternatively, at least part of the thermistor structure is formed simultaneously with the thermopile structure.

Each layer of the thermistor structure may be formed in the same manner as one of the electrodes of the thermopile structure, with the two acting only in different areas.

In this embodiment, the thermistor structure is formed in the process of forming the thermopile structure.

The thermistor structure is formed in the process of forming the thermopile structure, the manufacturing processes of the thermistor structure and the thermistor structure can be compatible, the thermistor structure and the thermistor structure are formed by the same manufacturing process, the manufacturing processes are saved, and the process is simple. Meanwhile, a semiconductor process is adopted to form the thermopile structure and the thermistor structure, so that the distance between the thermopile structure and the thermistor structure is small, and the size of the formed infrared thermopile sensor can be reduced.

Referring specifically to fig. 2-7, the thermistor structure is formed during the formation of the thermopile structure.

Referring to fig. 2, a first electrode material layer 202 is on the dielectric layer 201.

The first electrode material layer 202 provides material for the subsequent formation of a first electrode.

The material of the first electrode material layer 202 includes: doping a semiconductor material or a metal material, the doping ions comprising: p type ion or N type ion, the material of the metal includes: made of one of metals such as molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re), palladium (Pd), or a stack of the above metals, and a semiconductor material such as Si, Ge, SiGe, SiC, SiGeC, or the like. In this embodiment, the material of the first electrode material layer 202 is doped polysilicon or doped monocrystalline silicon.

The forming process of the first electrode material layer 202 includes: a deposition process or an epitaxial growth process. The epitaxial growth process further comprises: and (5) epitaxial doping process.

The method for forming the first electrode material layer 202 includes: forming a layer of undoped first electrode material (e.g., polysilicon or single crystal silicon, etc.) by an epitaxial process; performing ion implantation on the undoped first electrode material layer to form the first electrode material layer 202.

After the ion implantation, the method further includes performing an annealing process on the first electrode material layer 202, where the annealing process can repair lattice loss during the ion implantation and activate implanted ions in the ion implantation process.

In other embodiments, the first electrode material layer may also be formed by ion doping during epitaxial growth.

In this embodiment, the process of the first electrode material layer includes: and depositing and forming the first electrode material layer by adopting a sputtering process.

Referring to fig. 3, the first electrode material layer 202 is patterned to form a first electrode 211.

Since the thermopile structure includes a plurality of thermocouple pairs connected in series, each thermocouple pair includes a first electrode and a second electrode, the first electrode and the second electrode are connected with each other, and the first electrode and the second electrode of the adjacent thermocouple pairs are electrically connected with each other, each first electrode is separated.

The method for forming the first electrode 211 includes:

a first mask layer (not shown) is formed on the surface of the first electrode material layer 202, the first mask layer covers an area where a first electrode is to be formed, and the first electrode material layer 202 is etched by using the first mask layer as a mask to form a plurality of discrete first electrodes 211.

In an embodiment, the first electrode material layer 202 covers the surfaces of the dielectric layer 201 in the first region I and the second region II; during the process of patterning the first electrode material layer 202 to form the first electrode 211, the thermistor structure is formed.

The first electrode and the thermistor structure are both formed by patterning the first electrode material layer, so that the first electrode and the thermistor structure are made of the same material.

In other implementations, when the doping of the materials of the first electrode and the thermistor structure are different, the first region I and the second region II may be separately ion-implanted and then patterned together to form the first electrode and the thermistor structure.

In another embodiment, the thermistor structure is a multi-layer structure, and one of the thermosensitive layers of the thermistor structure is formed during the formation of the first electrode.

When the thermistor structure is a two-layer structure; when the first electrode is formed, a bottom thermosensitive layer of the thermistor structure is formed. The material of the bottom thermosensitive layer is the same as that of the first electrode.

In other embodiments, the thermistor structure may be formed after or before the first electrode is formed. Before or after, the first electrode material layer and the thermistor material layer may be formed sequentially, or the sequential relationship between the first electrode and the thermistor structure may be formed by patterning.

Referring to fig. 4, a passivation layer 203 is formed on the first substrate 200 and the first electrode 211, the passivation layer 203 having a first trench 204 therein, the first trench 204 exposing a portion of the surface of the first electrode 211.

The passivation layer 203 serves to protect the first electrode 211.

The material of the passivation layer 203 includes: one or more of silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxycarbonitride, silicon oxynitride, boron nitride, and boron carbonitride.

In this embodiment, the passivation layer 203 is made of silicon oxide.

The first trench 204 is used for forming a second electrode or forming an interconnection structure of the first electrode and the second electrode.

The method for forming the passivation layer 203 comprises the following steps: forming an initial passivation layer on the first electrode 211 and the first substrate 200; forming a second mask layer on the initial passivation layer, wherein the second mask layer exposes the initial passivation layer of the region where the second electrode is to be formed; and etching the initial passivation layer by using the second mask layer as a mask to form the first trench 204 and the passivation layer 203, wherein a part of the surface of the first electrode 211 is exposed by the first trench 204.

In this embodiment, the first trench 204 exposes a portion of the surface of the first substrate and a portion of the surface of the first electrode 211.

In an embodiment, the first trench 204 exposes only a portion of the surface of the first electrode 211.

When the thermistor structure is a multilayer structure and one of the thermosensitive layers has been formed during the formation of the first electrode, the passivation layer 203 in the second region II further has a second groove therein to expose the surface of the thermosensitive layer.

In one embodiment, the thermistor structure is a two-layer structure, and the second groove exposes the surface of the bottom thermosensitive layer.

After the first trench 204 is formed, the method further includes: and removing the second mask layer.

The material of the second mask layer comprises photoresist, and the process for removing the second mask layer comprises one or more of an ashing process and a wet etching process.

Referring to fig. 5a, a second electrode 212 is formed within the first trench 204.

The material of the second electrode 212 includes: doping a semiconductor material or a metal material, the doping ions comprising: p type ion or N type ion, the material of the metal includes: made of one of metals such as molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re), palladium (Pd), or a stack of the above metals, and a semiconductor material such as Si, Ge, SiGe, SiC, SiGeC, or the like.

In this embodiment, the material of the second electrode 212 is metal, for example: aluminum or copper.

The second electrode 212 connects the first electrodes 211 of adjacent thermocouple pairs in the thermopile structure.

The method for forming the second electrode 212 comprises the following steps: forming a second electrode material layer on the passivation layer 203, wherein the second electrode material layer fills the first trench 204; the second electrode material layer around the first trench 204 is removed to form the second electrode 212.

In one embodiment, the method for forming the second electrode 212 includes: after the first trench 204 is formed, depositing a second electrode material layer on the second mask layer; and removing the second mask layer by a wet etching process to form the second electrode 212.

In this embodiment, the thermistor structure 213 is a linear strip arranged in an S-shape, and referring to fig. 5b, fig. 5b is a top view of the thermistor structure 213.

Line width or the actual conditions of design basis in using in the thermistor structure rationally set up, the utility model discloses in do not limit.

In this embodiment, the infrared thermopile sensor in the cold junction of thermopile structure with thermistor structure 213 distance scope is 3um to 200 um.

The cold end of the thermopile structure is within a distance range of 3um to 200um from the thermistor structure 213. The heat at the hot end in the thermopile structure can be well ensured not to be rapidly radiated to the outside through the thermistor structure, the measurement precision of the infrared thermopile sensor is influenced, and the total area occupied by the thermopile and the thermosensitive structure can be ensured not to be too large.

The cold end of the thermopile structure is located in the peripheral region, where the distance is the minimum distance of the cold end from the thermistor structure 213.

In this embodiment, the thermistor structure 213 is formed during the formation of the second electrode 212.

Specifically, the process of forming the second electrode 212 further includes: and patterning the second electrode material layer on the second area II, and forming a thermistor structure on the surface of the passivation layer 203 of the second area II.

The second electrode 212 and the thermistor structure 213 are both formed by patterning the second electrode material layer, so that both materials are the same.

In other embodiments, when the materials of the second electrode 212 and the thermistor structure 213 are different, the first region I and the second region II may be patterned and the trench may be filled, respectively, to form the second electrode 212 and the thermistor structure 213. Or before or after forming the second electrode, forming a third mask layer on the first substrate 200, where the third mask layer covers the passivation layer 203 in the first region I and exposes a portion of the surface of the passivation layer 203 in the second region II, where the portion is used to form the thermistor structure; forming a thermistor material layer on the third mask layer; and removing the third mask layer to form the thermistor structure 213.

In another embodiment, the thermistor structure is a multi-layer structure, and one of the thermosensitive layers of the thermistor structure is formed during the formation of the second electrode.

When the thermistor structure is a two-layer structure; and forming a top thermosensitive layer of the thermistor structure when the second electrode is formed. The material of the top thermosensitive layer is the same as that of the second electrode.

In this embodiment, the thermistor structure is a single-layer structure and is formed simultaneously with the second electrode. The thermistor structure and the second electrode are made of aluminum.

The thermistor structure and the second electrode are formed at the same time, and the thermistor structure and the second electrode can be formed by the same patterning process, so that the manufacturing process can be saved. And the thermistor structure is positioned on the surface of the first substrate, so that the temperature of the thermopile chip can be better detected, the precision is improved, and the performance of the infrared thermopile sensor is improved.

The thermistor structure with the two-layer structure has the advantages that the bottom thermosensitive layer is doped polycrystalline silicon, the top thermosensitive layer is made of metal, the metal transmission rate is high, and the signal transmission rate can be improved.

The infrared thermopile sensor further includes: a first interconnect structure for connecting the thermopile structure to an external circuit.

The infrared thermopile sensor further includes: a second interconnect structure for connecting the thermistor structure to an external circuit.

In one embodiment, forming the second electrode further includes: a first interconnect structure is formed on the passivation layer 203, and the first interconnect structure is connected to a second electrode. The first interconnect structure is located in a first zone I peripheral zone.

The process of forming the thermistor structure further comprises: a second interconnect structure is formed on the passivation layer 203, the second interconnect structure being connected to a thermistor structure. The second interconnection structure is located in the region outside the second region II forming the thermistor.

In an embodiment, the first interconnect structure may be further located on the surface of the dielectric layer 201 and connected to the first electrode 211.

When the thermistor structure and the first electrode are formed simultaneously, the second interconnect structure may also be located on the surface of the dielectric layer 201 and connected to the thermistor structure.

The material of the first interconnection structure or the second interconnection structure can be one or more of metal such as copper, titanium, aluminum, tungsten and the like and/or metal silicide materials.

Referring to fig. 6, an absorption layer 205 is formed on the passivation layer 203.

The absorbing layer 205 is used to absorb infrared light and protect the second electrode 212 and the thermistor structure 213. In particular, the absorption layer of the radiation region is used for absorbing infrared light, converting heat energy, the second electrode and

the absorption layer 205 has a first opening 206 therein, the first opening 206 is located in the first region I, and the first opening 206 is used for subsequently forming an electrical connection structure to connect the thermopile structure and an external circuit.

In this embodiment, the absorption layer 205 has a second opening 207 therein, the second opening 207 is located in the second region II, and the second opening 207 is used for subsequently forming an electrical connection structure to connect the thermistor structure and an external circuit.

The material of the absorption layer 205 includes: one or more of silicon oxide, silicon nitride, silicon carbide, silicon carbonitride, silicon oxycarbonitride, silicon oxynitride, boron nitride, and boron carbonitride.

In this embodiment, the material of the absorption layer 205 is silicon nitride.

The forming process of the absorption layer 205 includes: a physical vapor deposition process or a chemical vapor deposition process.

In this embodiment, the method for forming the first opening 206 and the second opening 207 includes:

forming an initial absorption layer on the passivation layer 203, the initial absorption layer further covering the second electrode 212 and the thermistor structure 213; the initial absorber layer is patterned to form the first opening 205 and the second opening 207.

After the absorber layer 205 is formed, the substrate is etched from the second surface to form a thermal radiation isolation trench in the first region. Please refer to fig. 7 and 8.

Referring to fig. 7, a protective layer 208 is formed on the surface of the absorption layer 205.

The protective layer 208 protects the thermopile structure and the thermistor structure in a subsequent thinning process.

The material of the protective layer 208 includes: photoresist

The forming process of the protective layer 208 includes: and (4) spin coating.

In order to improve the precision of the subsequent thinning process, the protective layer can be subjected to chemical mechanical flat grinding, so that the flatness of the protective layer is improved.

Referring to fig. 8, the first substrate 200 is thinned from the second surface of the first substrate 200.

In this embodiment, the process of thinning the first substrate 200 is a chemical mechanical mask process. The thinning process may also be any process known in the art. For example, the first substrate is first ion implanted and then sliced. Or the first substrate 200 is thinned by adopting an etching process.

And thinning the first substrate 200 to reduce the process difficulty of subsequently forming a thermal radiation isolation groove.

With continued reference to fig. 8, the first substrate 200 is etched from the second surface of the first substrate 200, and a thermal radiation isolation groove 220 is formed in the first substrate 200 in the first region I.

The thermal radiation isolation groove 220 is located in the infrared radiation region.

The thermal radiation isolation groove 220 exposes a part of the thermopile structure, and the electrode end of the thermopile structure located in the thermal radiation isolation groove 220 region is the hot end of the thermopile structure.

The process of forming the heat radiation isolation layer 220 is one or more of a dry etching process or a wet etching process.

In an embodiment, the process of forming the thermal radiation isolation trench 220 further includes: and etching the first substrate 200 in the second area II to form an isolation groove, wherein the isolation groove exposes the dielectric layer in the area where the thermistor structure is located.

According to the infrared thermopile sensor formed by the method, the thermopile structure and the thermistor structure are both positioned on the first substrate, the integration level is high, and the size of the formed infrared thermopile sensor is reduced. And the thermopile structure and the thermistor structure can be formed by a semiconductor process, so that the compatibility is good. The thermistor structure is formed in the process of forming the thermoelectric stack structure, so that the processes of respectively forming and assembling the thermistor structure and the thermistor structure are omitted, and the process flow is simple.

Referring to fig. 9, before or after forming the thermal radiation isolation trench 200, further includes: an interlayer dielectric layer 217 is formed on the first surface of the first substrate 200. The interlayer dielectric layer 217 exposes the surface of the absorption layer of the infrared radiation region.

The interlayer dielectric layer 217 covers the absorption layer outside the infrared radiation region and fills the first opening.

A first interconnect structure is formed in the interlevel dielectric layer 217.

In this embodiment, forming the first interconnect structure includes: and forming a first plug and a first interconnection line.

In other embodiments, forming the first interconnect structure comprises: forming interconnect lines or forming pads.

The forming method of the first interconnection structure comprises the following steps: etching the interlayer dielectric layer 217 to form a plug opening exposing the second electrode 212; and forming an initial metal layer in the plug opening and on the interlayer dielectric layer 217, and patterning the initial metal layer to form the first interconnection structure.

The first interconnection structure located in the plug opening is a first plug 231, the first interconnection structure located on the interlayer dielectric layer is a first interconnection line 241, the first plug 231 is connected with the second electrode 212, and the first plug interconnection line 241 is connected with the first plug 231.

After forming the first interconnect structure, forming the thermistor structure; or, after forming the thermistor structure, forming the first interconnect structure; alternatively, at least part of the thermistor structure is formed simultaneously with the first interconnect structure.

In one embodiment, the thermistor structure is formed during the formation of the first interconnect structure. That is, in the process of patterning the initial metal layer, a thermistor structure is formed on the interlayer dielectric layer 217 of the second region II.

That is, the thermistor structure is formed during the formation of the first plugs 231 or the formation of the first interconnection lines 241, or the thermistor structure is formed during the formation of the first plugs 231 and the formation of the first interconnection lines 241.

In this embodiment, in the process of forming the first interconnect structure, the second interconnect structure is formed.

The second interconnect structure includes: the second plug 232 is located in the interlayer dielectric layer 217 of the second area II, and the second interconnecting line is located on the interlayer dielectric layer 217 of the second area II, the second plug 232 is connected with the thermistor structure 213, and the second interconnecting line is connected with the second plug 232.

In other embodiments, after forming the first interconnect structure, forming the second interconnect structure; or after the second interconnection structure is formed, the first interconnection structure is formed.

After forming galvanic pile structure and thermistor structure, still include: a first connection structure is formed to connect the thermopile structure to an external circuit. A second connecting structure is formed to connect the thermistor structure to an external circuit.

In this embodiment, a first connection structure is formed to connect the first interconnect structure with an external circuit. Forming a second connection structure connecting the second interconnect structure to an external circuit.

The first connection structure includes: a third plug 233 located in the first region I peripheral region and penetrating through the interlayer dielectric layer 217, the absorption layer, the passivation layer and the first substrate 200, and a third interconnection 243 located on the second surface of the first substrate 200.

The second connecting structure includes: the region of the non-thermistor structure in the second region II penetrates through the interlayer dielectric layer 217, the absorber layer, the passivation layer and the fourth plug 234 of the first substrate 200 and the fourth interconnection line 244 on the second surface of the first substrate 200.

In one embodiment, the method for forming the first connection structure includes:

in the process of forming the thermal radiation isolation groove 200, the first substrate 200, the passivation layer 203 and the absorption layer 205 in the peripheral region are etched to form a third opening, and the first interconnection structure is exposed out of the third opening; forming a third plug within the third opening; and forming a third interconnecting wire on the second surface of the first substrate.

The method for forming the second connection structure comprises the following steps:

in the process of forming the thermal radiation isolation groove 200, etching the first substrate 200, the passivation layer 203 and the absorption layer 205, in which the thermistor structure is not formed, in the second region II to form a fourth opening, which exposes the second interconnection structure; forming a fourth plug within the fourth opening; and forming a fourth interconnecting wire on the second surface of the first substrate.

The material of the first connection structure or the second connection structure may be one or more of metal such as copper, titanium, aluminum, tungsten, and/or metal silicide material.

In an embodiment, solder balls are formed on the third interconnect lines 243 and the fourth interconnect lines 244 to facilitate subsequent connection to external circuits.

Referring to fig. 10, a second substrate 100 is provided; and bonding the second substrate 100 with the second surface of the first substrate 200, so that the thermal radiation isolation groove is sandwiched between the thermopile structure and the second substrate 100 to form a first cavity.

The second substrate 100 has a readout circuit therein.

The forming method of the infrared thermopile sensor further comprises the following steps:

a third interconnection structure is formed in the second substrate 100 to connect the first connection structure with an external circuit. Specifically, the third interconnect lines 243 are connected by the fifth plugs, so that the thermopile structure is electrically connected to an external signal.

A fourth interconnection structure is formed in the second substrate 100 to connect the second connection structure with an external circuit. Specifically, the fourth interconnecting lines 244 are connected by the sixth plugs, so as to electrically connect the thermistor structure and an external signal.

The third and fourth interconnect structures include: insulating layer 101 and metal layer 110.

The forming method of the third interconnection structure and the fourth interconnection structure comprises the following steps: etching the second substrate 100 until the third interconnection line 243 and the fourth interconnection line 244 are exposed, and forming a fifth opening and a sixth opening respectively; forming an insulating layer 101 on a surface of the second substrate 100 opposite to the first substrate 200, wherein the insulating layer also covers sidewalls of the fifth opening and the sixth opening; etching the insulating layer 101 to expose the third interconnection line 243 and the fourth interconnection line 244 at the bottom of the fifth opening and the sixth opening; forming an initial metal layer on the surface of the insulating layer 101, the initial metal layer being connected to the third interconnection line 243 and the fourth interconnection line 244; the initial metal layer is patterned to form the metal layer 110.

In an embodiment, the method further includes forming an interconnection line in the second substrate 100, the interconnection line being connected to a readout circuit in the second substrate 100, and the interconnection line being electrically connected to the metal layer 110, so that the readout circuit is electrically connected to the thermopile structure and the thermistor structure.

In this embodiment, forming a cap 300 on the first surface of the first substrate 200 is further included.

Referring to fig. 11, a cap 300 is bonded on the interlayer dielectric layer 217.

The interlayer dielectric layer 217 and the cap 300 are bonded by a bonding layer 301, and the material of the bonding layer includes a dry film or other suitable materials.

Wherein, the material of the sealing cover can be glass, plastic, semiconductor and the like,

a radiation transmissive window may be formed over the infrared radiation region of the cover.

Wherein the material of the cover can be glass, plastic, semiconductor, etc., and the infrared radiation area of the thermopile structure is covered by bonding the cover to the surface of the thermopile structure plate, which faces away from the second substrate.

The shape of the radiation penetration window can be selected according to the requirement, such as a circle, a rectangle and the like. The material of the radiation transparent window comprises one or two of a semiconductor (such as silicon, wire or ring, silicon on insulator, etc.) or an organic filter material (such as polyethylene, polypropylene, etc.).

An infrared filter layer 302 may be disposed on the radiation transmissive window. The infrared filter layer 302 filters infrared light of a specific wavelength to reduce optical crosstalk.

The infrared filter layer 302 is made of an infrared filter.

After the cap is formed, solder balls are formed on the surface of the second substrate 100 away from the first substrate 200 to connect the external circuit with the third plug and the fourth plug.

Fig. 12 is a schematic diagram of an infrared thermopile sensor in another embodiment, in which the first interconnect structure is an interconnect line or pad, and is not formed in an interlevel dielectric layer.

In this embodiment, the first interconnect structure is an interconnect line having an electrode interconnect end 214.

After forming the first interconnect structure, forming the thermistor structure; alternatively, the first interconnect structure is formed after the thermistor structure is formed.

In this embodiment, the thermistor structure is formed simultaneously with the first interconnect structure.

In other implementations, the first interconnect structure further includes a pad.

In this embodiment, the first interconnection structure is formed in the process of forming the second electrode.

The first connection structure is connected to the electrode interconnect 214 and the second connection structure is connected to the thermistor structure.

The forming method of the first connecting structure comprises the following steps: in the process of forming the thermal radiation isolation groove 200, the first substrate 200, the passivation layer 203 and the absorption layer 205 of the peripheral region are etched to form a third opening, and the electrode interconnection terminal 214 is exposed from the third opening; forming a third plug 233 in the third opening; a third interconnect line 243 is formed on the second surface of the first substrate.

The third interconnecting line 243 is connected to a third interconnecting structure in the second substrate 100 to introduce an external electrical signal to the thermopile structure.

The method for forming the second connection structure comprises the following steps: in the process of forming the thermal radiation isolation groove 200, etching the first substrate 200, the passivation layer 203 and the absorption layer 205, which do not form the thermistor structure, in the second region II to form a fourth opening, wherein the thermistor structure is exposed out of the fourth opening; forming a fourth plug 234 within the fourth opening; a fourth interconnect line 244 is formed on the first substrate second surface.

The fourth interconnection line 244 is connected to a fourth interconnection structure in the second substrate 100 to introduce an external electrical signal to the thermistor structure.

The utility model also provides an infrared thermopile sensor, as shown in FIG. 11, include:

a first substrate 200, the first substrate 200 including a first region I and a second region II, the first substrate 200 having opposing first and second surfaces;

the first surface of the first region I is provided with a thermopile structure;

and the first surface of the second region II is provided with a thermistor structure.

The infrared thermopile sensor further includes: a thermal radiation isolation groove 220 penetrating the first substrate 200 from the rear surface of the first region I, the thermal radiation isolation groove 220 being opposite to the thermopile structure.

In the infrared thermopile sensor, the thermistor structure 213 includes: a single layer film structure or a multi-layer film structure. When the thermistor structure is a multilayer film structure, the materials of all the film layers can be the same or different, or the doping concentrations of all the film layers are the same or different.

The infrared thermopile sensor, the thermopile structure includes: a first electrode and a second electrode;

the material of the first electrode is the same as that of one layer of the thermistor structure 213, and both are located in the same layer;

in another embodiment, the material of the second electrode is the same as that of one layer of the thermistor in the thermal resistor structure, and the second electrode and the thermistor are located in the same layer.

The materials, shapes and structures of the first electrode, the second electrode and the thermistor structure are specifically described with reference to the foregoing embodiments, and are not repeated herein.

In one embodiment, the infrared thermopile sensor further includes: a first interconnect structure electrically connecting the thermopile structure;

the first interconnect structure includes: a first interconnection line and a first plug;

one of the thermistor layers in the thermistor structure is located at the same layer as the first interconnection line or the first plug of the first interconnection structure.

In another embodiment, referring to fig. 12, the first interconnect structure includes: an interconnect line or pad; the thermistor structure is located in the same layer as the interconnect line or pad.

In the infrared thermopile sensor, the thermopile structure and the thermosensitive structure are both formed on the first substrate, so that the size of the formed infrared thermopile sensor can be reduced, and the integration level of devices is improved.

Although the embodiments of the present invention are disclosed above, the embodiments of the present invention are not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the embodiments of the present invention, and it is intended that the scope of the embodiments of the present invention be defined by the appended claims.

Claims

1. An infrared thermopile sensor, comprising:

the first surface of the first region is provided with a thermopile structure;

the first surface of the second area is provided with a thermistor structure.

2. The infrared thermopile sensor of claim 1, wherein the thermistor structure comprises: a single layer film structure or a multi-layer film structure.

3. The infrared thermopile sensor of claim 1, wherein the thermopile structure comprises: a first electrode and a second electrode;

the material of the first electrode is the same as that of one layer of the thermistor structure, and the first electrode and the thermistor structure are positioned on the same layer;

or the material of the second electrode is the same as one layer of the thermistor structure, and the second electrode and the thermistor structure are positioned in the same layer.

4. The infrared thermopile sensor of claim 1, wherein the thermistor structure is located on the first substrate below the thermopile structure.

5. The infrared thermopile sensor of claim 1, wherein the thermistor structure is located above the thermopile structure.

6. The infrared thermopile sensor of claim 1, further comprising: a first interconnect structure electrically connecting the thermopile structure;

one layer of the thermistors in the thermistor structure is positioned at the same layer as the first interconnection line or the first plug of the first interconnection structure;

alternatively, the first and second electrodes may be,

the first interconnect structure includes: an interconnect line or pad; the thermistor structure is located in the same layer as the interconnect line or pad.

7. The infrared thermopile sensor of claim 1, wherein the cold end of the thermopile structure is located a distance from the thermistor structure in the range of 3um to 200 um.

8. The infrared thermopile sensor of claim 1, wherein a back surface of the first region has a thermal radiation isolation slot extending through the first substrate, the thermal radiation isolation slot being opposite the thermopile structure.

9. The infrared thermopile sensor of claim 8, further comprising: and the second substrate is bonded with the first substrate, so that the heat radiation isolation groove is clamped between the thermopile structure and the second substrate to form a first cavity.

10. The infrared thermopile sensor of claim 8, further comprising: and the cover plate is bonded with the first substrate, and the part of the cover plate corresponding to the thermal radiation isolation groove is provided with an infrared filter layer.