CN111854976A - Infrared thermopile sensor and manufacturing method thereof - Google Patents

Infrared thermopile sensor and manufacturing method thereof Download PDF

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Publication number
CN111854976A
CN111854976A CN202010694077.9A CN202010694077A CN111854976A CN 111854976 A CN111854976 A CN 111854976A CN 202010694077 A CN202010694077 A CN 202010694077A CN 111854976 A CN111854976 A CN 111854976A
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China
Prior art keywords
electrode
thermistor
layer
thermopile
substrate
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CN202010694077.9A
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Chinese (zh)
Inventor
韩凤芹
刘孟彬
狄云翔
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Smic Ningbo Co ltd Shanghai Branch
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Smic Ningbo Co ltd Shanghai Branch
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Priority to CN202010694077.9A priority Critical patent/CN111854976A/en
Priority to CN202011133388.4A priority patent/CN112129418A/en
Publication of CN111854976A publication Critical patent/CN111854976A/en
Pending legal-status Critical Current

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/10Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
    • G01J5/20Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J5/00Radiation pyrometry, e.g. infrared or optical thermometry
    • G01J5/10Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
    • G01J5/20Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
    • G01J2005/202Arrays
    • G01J2005/204Arrays prepared by semiconductor processing, e.g. VLSI

Abstract

The embodiment of the invention provides an infrared thermopile sensor and a manufacturing method thereof, wherein the infrared thermopile sensor comprises the following steps: 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; forming a thermistor structure on the first surface of the second area; and etching the first substrate from the second surface to form a thermal radiation isolation groove in the first area. The thermopile structure and the thermistor structure of the infrared thermopile sensor obtained by the method for manufacturing the infrared thermopile sensor provided by the embodiment of the invention are integrated on the first substrate, so that the integration level is high, the volume is small, and the process is simple.

Description

Infrared thermopile sensor and manufacturing method thereof
Technical Field
The invention relates to the field of semiconductor manufacturing, in particular to a manufacturing method of 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.
Disclosure of Invention
The invention solves the problem of how to reduce the device volume of the infrared thermopile sensor and simplify the process flow.
In order to solve the above problems, the present invention provides a method for manufacturing an infrared thermopile sensor, comprising:
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;
forming a thermistor structure on the first surface of the second area;
and etching the substrate from the second surface to form a thermal radiation isolation groove in the first area.
The invention also provides an infrared thermopile sensor comprising:
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 back surface of the first region is provided with a thermal radiation isolation groove penetrating through the first substrate, and the thermal radiation isolation groove is opposite to the thermopile structure.
Compared with the prior art, the technical scheme of the embodiment of the invention has the following advantages:
in the manufacturing method of the infrared thermopile sensor, the thermopile structure and the thermosensitive structure are both formed on the first substrate and are both formed by adopting a semiconductor process, so that the size of the formed infrared thermopile sensor can be reduced, and the integration level of devices is improved.
Furthermore, the thermopile structure and the thermistor structure can be formed through a semiconductor process, and the compatibility is good.
Furthermore, a 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.
In the infrared thermopile sensor provided by the invention, the thermopile structure and the thermosensitive structure are both formed on the first substrate, so that the volume of the formed infrared thermopile sensor can be reduced, and the integration level of devices is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings 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 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.
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 as a thermopile infrared detector, the traditional infrared thermopile sensor comprises a thermopile chip and a thermistor chip, and 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 the 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;
forming a thermistor structure on the first surface of the second area;
and etching the substrate from the second surface to form a thermal radiation isolation groove in the first area.
In the method for manufacturing the infrared thermopile sensor provided by the embodiment of the invention, the thermopile structure and the thermistor structure are both formed on the first substrate, and the distance between the thermopile structure and the thermistor structure can be relatively short, so that the volume of the formed infrared thermopile sensor is reduced.
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 clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within 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.
The first base 200 may be any suitable substrate material known to those skilled in the art, such as a bulk semiconductor substrate material of silicon, germanium, silicon germanium, gallium arsenide, indium phosphide, or the like.
The first substrate 200 has opposite first and second surfaces.
In this embodiment, a dielectric layer 201 is formed on the first substrate 200.
The dielectric layer 201 is used for isolating a thermopile structure formed subsequently from a first substrate, and serves 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 thermistor structure includes: the thermistor structure is a multilayer film structure, and materials of all film layers are different or doping concentrations of all film layers are different.
The thermistor structure is a linear strip which is arranged in a snake shape or a spiral shape.
The material of the thermistor structure is the same as that of the first electrode or the second electrode.
The thermistor structure is made of a material with a negative temperature coefficient, and comprises the following components: one, two or more than two metals or metal oxides of manganese, copper, silicon, cobalt, iron, nickel, zinc and the like; 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 thermistor structure is formed in the process of forming 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: an epitaxial growth process or an ion 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 be formed by epitaxial growth.
Referring to fig. 3, the first electrode material layer 202 is patterned to form a first electrode 211.
The thermopile structure comprises a plurality of thermocouple pairs connected in series, each thermocouple pair comprises a first electrode and a second electrode, the first electrodes and the second electrodes are connected with each other, and the first electrodes and the second electrodes of the adjacent thermocouple pairs are electrically connected with each other.
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 one embodiment, the thermistor structure is formed during the formation of the first electrode 211.
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 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.
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; 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 a serpentine shape, and referring to fig. 5b, fig. 5b is a top view of the thermistor structure 213.
The line width or design in the thermistor structure is reasonably set according to the actual situation in application, and the invention is not limited.
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, in the process of forming the second electrode 212 in the first trench 204, a thermistor structure is further formed on the surface of the passivation layer 203 in the second region 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 for forming 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 has a single-layer structure and is formed simultaneously with the second electrode.
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 thermopile structure further includes: a first interconnect structure for connecting external circuitry.
The thermistor structure further includes: a second interconnect structure for connecting external circuitry.
In one embodiment, forming the second electrode further includes: a second 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 206 is used for 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 207 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.
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 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 207 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 first plug within the third opening; forming a third interconnection structure on the second surface of the first substrate; and forming a solder ball on the third interconnection structure so as to introduce an external electrical signal.
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 207, 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 second plug within the fourth opening; forming a fourth interconnection structure on the second surface of the first substrate; and forming a solder ball on the fourth interconnection structure so as to introduce an external electrical signal.
In one embodiment, the thermistor structure is formed during the formation of the first interconnect structure.
Referring to fig. 9, after forming the thermal radiation isolation trench 200, the method 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.
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 plug interconnection line 240, the first plug 231 is connected with the second electrode 212, and the first plug 231 interconnection line 241 is connected with the first plug 231.
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.
In this embodiment, in the process of forming the first interconnect structure, the second interconnect structure is formed.
The second interconnect structure includes: a second plug 232 located in the interlayer dielectric layer 217 of the second region II and a second plug interconnection line 242 located on the interlayer dielectric layer 217 of the second region II, wherein the second plug 232 is connected with the thermistor structure 213, and the second plug interconnection line 242 is connected with the second plug 232.
In this embodiment, forming a first connection structure to connect the first interconnect structure to an external circuit is further included. 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 plug interconnection line 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 plug interconnection 244 on the second surface of the first substrate 200.
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 plug interconnect lines 243 and the fourth plug interconnect lines 244 to facilitate subsequent connection to external circuits.
Referring to fig. 10, a second substrate is provided; and bonding the second substrate with the second surface of the first substrate, so that the thermal radiation isolation groove is clamped between the thermopile structure and the second substrate to form a first cavity.
The second substrate has a readout circuit therein. The forming method of the infrared thermopile sensor further comprises the following steps:
and forming a third interconnection structure in the second substrate, and connecting the first connection structure with a readout circuit. Specifically, the third plug interconnection line 243 is connected to the readout circuit through the fifth plug.
And forming a fourth interconnection structure in the second substrate, and connecting the second connection structure with a readout circuit. Specifically, the fourth plug interconnection line 244 and the readout circuit are connected by a sixth plug.
In this embodiment, forming a cover 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 connection structure and the second connection structure are not formed on the interlayer dielectric layer.
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 207 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 first plug within the third opening; and forming a third interconnection structure on the second surface of the first substrate.
The third interconnection structure is connected with a third interconnection structure in the second substrate so as to introduce an external electrical signal.
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 207, 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 second plug within the fourth opening; and forming a fourth interconnection structure on the second surface of the first substrate.
And the fourth interconnection structure is connected with the fourth interconnection structure in the second substrate so as to lead in external electric signals.
The present invention also provides an infrared thermopile sensor comprising:
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;
the first surface of the second area II is provided with a thermistor structure;
the rear surface of the first region I has a thermal radiation isolation groove 220 penetrating the first substrate 200, the thermal radiation isolation groove 220 being opposite to the thermopile structure.
In the infrared thermopile sensor, the thermistor structure 213 includes: in the case where the thermistor structure 213 is a multilayer film structure, the material of each film layer is different or the doping concentration is 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: interconnection lines and conductive plugs;
one layer of the thermistors in the thermistors structure is positioned at the same layer as the interconnection line or the conductive plug of the first interconnection structure.
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.
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 present embodiments, and it is intended that the scope of the present embodiments be defined by the appended claims.

Claims (17)

1. A manufacturing method of an infrared thermopile sensor is characterized by comprising the following steps:
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;
forming a thermistor structure on the first surface of the second area;
and etching the first substrate from the second surface to form a thermal radiation isolation groove in the first area.
2. The method of making an infrared thermopile sensor of claim 1, wherein said thermistor structure comprises: the thermistor structure is a multilayer film structure, and materials of all film layers are different or doping concentrations of all film layers are different.
3. The method of making an infrared thermopile sensor of claim 1, wherein said thermopile structure comprises: a first electrode and a second electrode;
The thermistor structure is a single-layer film structure; the thermistor structure is formed when the first electrode is formed or when the second electrode is formed.
4. The method of claim 1, wherein the thermistor structure is made of the same material as the first electrode or the second electrode.
5. The method of making an infrared thermopile sensor of claim 1, wherein said thermopile structure comprises: a first electrode and a second electrode;
the thermistor structure is a two-layer structure; when the first electrode is formed and when the second electrode is formed, corresponding film layers of the thermistor structure are formed respectively.
6. The method for manufacturing an infrared thermopile sensor of claim 1, wherein the thermistor structure is made of a material comprising one, two or more metals or metal oxides of manganese, copper, silicon, cobalt, iron, nickel, zinc, etc.; 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.
7. The method of claim 1, wherein the thermistor has a shape comprising a serpentine or helical arrangement of linear surface electrodes.
8. The method of making an infrared thermopile sensor of claim 2, wherein said thermopile structure is formed by a method comprising:
forming a first electrode material layer on the first substrate; patterning the first electrode material layer to form a plurality of discrete first electrodes, wherein a first groove is formed between every two adjacent first electrodes;
forming a barrier layer on the first substrate and the first electrode, wherein the barrier layer covers the first electrode and fills the first groove; patterning the barrier layer to form a second groove, wherein part of the surface of the first electrode is exposed out of the second groove;
forming a second electrode material layer in the second trench and on the barrier layer; patterning the second electrode material layer to form a plurality of discrete second electrodes;
the first electrodes and the second electrodes of the adjacent thermocouple pairs are mutually and electrically connected to form a plurality of groups of thermocouple pairs, and the thermocouple pairs are electrically connected in series.
9. The method of claim 3, wherein the material of the first electrode and/or the second electrode comprises: 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: molybdenum, aluminum, copper, tungsten, tantalum, platinum, ruthenium, rhodium, iridium, chromium, titanium, gold, osmium, rhenium, palladium.
10. The method of claim 3, wherein the thermistor structure is a single-layer structure; the thermistor structure is formed when the first electrode is formed or when the second electrode is formed.
11. The method of making an infrared thermopile sensor of claim 1, wherein said thermopile structure further comprises: a first interconnect structure electrically connecting the thermopile structure;
the forming method of the first interconnection structure comprises the following steps:
forming a dielectric layer on the first surface of the first substrate, wherein the dielectric layer covers the thermopile structure;
etching the dielectric layer to form an opening exposing the thermopile structure;
and forming a first interconnection structure which is interconnected with the thermopile structure in the opening and on the dielectric layer.
12. The method of claim 6, wherein the thermistor structure is formed during the process of forming the first interconnect structure.
13. An infrared thermopile sensor, comprising:
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 back surface of the first region is provided with a thermal radiation isolation groove penetrating through the first substrate, and the thermal radiation isolation groove is opposite to the thermopile structure.
14. The infrared thermopile sensor of claim 13, wherein the thermistor structure comprises: the thermistor structure is a multilayer film structure, and materials of all film layers are different or doping concentrations of all film layers are different.
15. The infrared thermopile sensor of claim 13, 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 of the thermal resistance structure, and the first electrode and the thermistor are positioned on the same layer;
or the material of the first electrode is the same as that of one layer of the thermistor in the thermal resistance structure, and the first electrode and the thermistor are positioned in the same layer.
16. The infrared thermopile sensor of claim 13, further comprising: a first interconnect structure electrically connecting the thermopile structure;
The first interconnect structure includes: interconnection lines and conductive plugs;
interconnection line or interconnection line of one layer of thermistor in thermistor structure and first interconnection structure
The conductive plugs are located in the same layer.
17. The infrared thermopile sensor of claim 13, wherein the cold end of the thermopile structure is located a distance from the thermistor structure in the range of 3um to 200 um.
CN202010694077.9A 2020-07-17 2020-07-17 Infrared thermopile sensor and manufacturing method thereof Pending CN111854976A (en)

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CN113340366A (en) * 2021-06-08 2021-09-03 百易晟信息科技(苏州)有限公司 Double-sided MEMS (micro-electromechanical system) thermal type gas flow sensor and manufacturing method thereof

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CN112736185B (en) * 2020-12-28 2023-08-08 中芯集成电路(宁波)有限公司 Manufacturing method of infrared thermopile sensor

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113340366A (en) * 2021-06-08 2021-09-03 百易晟信息科技(苏州)有限公司 Double-sided MEMS (micro-electromechanical system) thermal type gas flow sensor and manufacturing method thereof

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