CN113104804A - Infrared thermopile sensor, chip and preparation method thereof - Google Patents

Infrared thermopile sensor, chip and preparation method thereof Download PDF

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Publication number
CN113104804A
CN113104804A CN202110389130.9A CN202110389130A CN113104804A CN 113104804 A CN113104804 A CN 113104804A CN 202110389130 A CN202110389130 A CN 202110389130A CN 113104804 A CN113104804 A CN 113104804A
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thermopile
substrate
region
infrared
type
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费跃
焦继伟
刘京
陈思奇
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Shanghai Core Technology Co ltd
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Shanghai Core Technology Co ltd
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/10—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects operating with only the Peltier or Seebeck effects
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
    • B81B7/0032—Packages or encapsulation
    • B81B7/007—Interconnections between the MEMS and external electrical signals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
    • B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/01—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80—Constructional details
    • H10N10/81—Structural details of the junction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2201/00—Specific applications of microelectromechanical systems
    • B81B2201/02—Sensors
    • B81B2201/0278—Temperature sensors

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Computer Hardware Design (AREA)
  • Manufacturing & Machinery (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Abstract

The embodiment of the invention discloses an infrared thermopile sensor, a chip and a preparation method thereof. The substrate includes a first region and a second region. The first suspended film is positioned on one side of the substrate and positioned in the first area, and the second suspended film is positioned on one side of the substrate and positioned in the second area. The N-type thermopile, the P-type thermopile and the switch circuit are positioned on one side of the first suspended film, which is far away from the substrate. The switch circuit is located between the N-type thermopile and the P-type thermopile. The cantilever beam and the switching signal derivation structure are positioned on one side, away from the substrate, of the second suspension film, and the switching signal derivation structure is electrically connected with the switching circuit. Through setting up switching circuit between N type thermopile and P type thermopile, be favorable to reducing the area of infrared thermopile sensor, improve infrared thermopile sensor's fill factor, and then promote its sensitivity, reduce manufacturing cost, realize the miniaturization.

Description

Infrared thermopile sensor, chip and preparation method thereof
Technical Field
The embodiment of the invention relates to the technology of infrared thermopile sensors, in particular to an infrared thermopile sensor, an infrared thermopile chip and a preparation method of the infrared thermopile sensor.
Background
The infrared thermopile sensor is a sensor which converts infrared radiation energy into an electric signal and outputs the electric signal by utilizing the seebeck effect. The infrared thermopile sensor can be manufactured into an infrared array sensor chip with a certain scale by combining MEMS and CMOS processes, all measured objects in a certain area are detected in a two-dimensional plane mode, respective temperature distribution states are shown, and the infrared thermopile sensor is widely applied to various intelligent household products.
A single pixel in the structure of a conventional infrared thermopile sensor is divided into two parts, one part being an infrared thermopile structure; the other part is a MOS tube switch circuit which is usually arranged on the side of the thermopile structure of each pixel and occupies a certain area. Due to the planar arrangement mode, when actual infrared radiation enters the infrared thermopile array sensor, the area of the MOS tube switch circuit cannot absorb the infrared radiation, so that the absorption efficiency of the whole sensor is lowered, and the filling factor of the whole sensor array is not high. Therefore, the sensitivity of the infrared thermopile array chip cannot be effectively improved, the two-dimensional plane imaging and the temperature measurement accuracy in practical application can be influenced, meanwhile, the chip area can also be increased due to the fact that the MOS tube switch circuit occupies a part of area, and the requirement for miniaturization is not met while the manufacturing cost is increased.
Disclosure of Invention
The embodiment of the invention provides an infrared thermopile sensor, a chip and a preparation method thereof, which are used for improving the filling factor of the infrared thermopile sensor, improving the infrared absorption efficiency, realizing the miniaturization of the infrared thermopile sensor and reducing the manufacturing cost.
In a first aspect, an embodiment of the present invention provides an infrared thermopile sensor, including a plurality of infrared thermopile pixels, where the infrared thermopile pixels include:
a substrate comprising a first region and a second region, the second region surrounding the first region;
the first suspended film is positioned on one side of the substrate and positioned in the first area, and the second suspended film is positioned on one side of the substrate and positioned in the second area;
the thermopile structure and the switch circuit are positioned on one side, far away from the substrate, of the first suspended film, the thermopile structure comprises an N-type thermopile and a P-type thermopile, and the switch circuit is positioned between the N-type thermopile and the P-type thermopile;
the cantilever beam and the switching signal derivation structure are positioned on one side, far away from the substrate, of the second suspension film, and the switching signal derivation structure is electrically connected with the switching circuit.
Optionally, the cantilever beam includes a first cantilever beam and a second cantilever beam;
the first cantilever beam is respectively and electrically connected with the N-type thermopile and the first metal contact hole to form a cold end signal transmission path of the infrared thermopile sensor;
and the second cantilever beam is respectively and electrically connected with the P-type thermopile and the second metal contact hole to form a hot end signal transmission path of the infrared thermopile sensor.
Optionally, the switch circuit includes a source, a gate, a drain, and a ground via;
the switch signal leading-out structure comprises a source electrode connecting wire, a grid electrode connecting wire, a drain electrode connecting wire and a grounding connecting wire;
the source electrode connecting wire is electrically connected with the second metal contact hole and the source electrode respectively to form an input signal transmission path of the switch circuit;
the grid connecting line is electrically connected with the switch signal connecting line and the grid respectively to form a switch signal transmission path of the switch circuit;
the drain electrode connecting wire is respectively and electrically connected with an output signal receiving end and the drain electrode to form an output signal transmission path of the switch circuit;
the grounding connecting wire is electrically connected with the grounding signal terminal and the grounding hole respectively to form a grounding signal transmission path of the switch circuit.
Optionally, a vertical projection of the source connecting line located in the second region on the plane of the substrate overlaps with a vertical projection of the second cantilever beam on the plane of the substrate;
the vertical projection of the ground connection line on the plane of the substrate in the second area is overlapped with the vertical projection of the first cantilever beam on the plane of the substrate.
Optionally, the N-type thermopile, the P-type thermopile, the gate, and the gate connection line are disposed on the same layer;
the source electrode, the drain electrode, the grounding hole, the source electrode connecting wire, the drain electrode connecting wire and the grounding connecting wire are arranged on the same layer.
Optionally, the infrared thermopile sensor further includes an N-well region and a P-well region;
the N-well region and the P-silicon region are located between the first suspended film and the substrate, and the P-well region is located in the N-well region.
Optionally, the N-type thermopile and the P-type thermopile are electrically connected through a third metal contact hole.
In a second aspect, an embodiment of the present invention further provides an infrared thermopile sensor chip, including a plurality of infrared thermopile sensors described in any one of the above;
and a plurality of infrared thermopile sensor arrays are arranged.
In a third aspect, an embodiment of the present invention further provides a preparation method of an infrared thermopile sensor, for preparing any one of the infrared thermopile sensors, where the preparation method includes:
providing a substrate;
preparing a first oxidation layer on one side of the substrate, wherein the first oxidation layer comprises a first region, a second region, a first spacing region positioned between the first region and the second region, and a second spacing region positioned on one side, far away from the first region, of the second region;
preparing a thermopile structure and a switching circuit on one side of the first oxidation layer far away from the substrate and in the first area, and preparing a cantilever beam and a switching signal leading-out structure on one side of the first oxidation layer far away from the substrate and in the second area; the thermopile structure comprises an N-type thermopile and a P-type thermopile, the switching circuit is positioned between the N-type thermopile and the P-type thermopile, and the switching signal derivation structure is electrically connected with the switching circuit;
etching the substrate in the first interval region and the second interval region to form a cavity; the first oxide layer located on the surface of the cavity and in the first area is a first suspended film, and the first oxide layer located on the surface of the cavity and in the second area is a second suspended film.
Optionally, the cantilever beam includes a first cantilever beam and a second cantilever beam;
the switch circuit comprises a source electrode, a grid electrode, a drain electrode and a grounding hole;
the switch signal leading-out structure comprises a source electrode connecting wire, a grid electrode connecting wire, a drain electrode connecting wire and a grounding connecting wire;
the infrared thermopile sensor further comprises an N-well region and a P-well region; the N-well region and the P-well region are positioned between the first suspended film and the substrate, and the P-well region is positioned in the N-well region;
preparing a thermopile structure and a switching circuit on a side of the first oxide layer away from the substrate and in the first region, preparing a cantilever beam and a switching signal deriving structure on a side of the first oxide layer away from the substrate and in the second region, comprising:
carrying out N-type doping on the substrate by utilizing a CMOS photoetching development technology to form an N-well region;
performing P-type doping on the N-well region by utilizing a CMOS photoetching development technology to form a P-well region;
preparing a polysilicon layer on one side of the first oxidation layer, which is far away from the substrate, and etching the polysilicon layer to form the N-type thermopile, the P-type thermopile, the grid and the grid connecting line;
preparing a second oxide layer on one side of the polycrystalline silicon layer, which is far away from the substrate, and etching the first oxide layer and the second oxide layer by utilizing a CMOS photoetching development technology to form a source contact hole, a drain contact hole, a first metal contact hole and a second metal contact hole;
preparing a metal layer on one side of the second oxide layer, which is far away from the substrate, and forming the source electrode, the drain electrode, the source electrode signal wire, the drain electrode connecting wire and the grounding wire;
etching the first oxide layer and the second oxide layer in the first interval area and the second interval area to form an etching hole;
and etching the substrate by using the etching hole to form the cantilever beam, the first suspended film, the second suspended film and the cavity.
The invention provides an infrared thermopile sensor, a chip and a preparation method thereof. The first suspended film is positioned on one side of the substrate and positioned in the first area, and the second suspended film is positioned on one side of the substrate and positioned in the second area. The thermopile structure and the switch circuit are positioned on one side, far away from the substrate, of the first suspended film. The thermopile structure comprises an N-type thermopile and a P-type thermopile, and the switching circuit is positioned between the N-type thermopile and the P-type thermopile. The cantilever beam and the switching signal derivation structure are positioned on one side, away from the substrate, of the second suspension film, and the switching signal derivation structure is electrically connected with the switching circuit. Through setting up switch circuit between N type thermopile and P type thermopile and be located first unsettled membrane and keep away from substrate one side, be favorable to improving infrared thermopile sensor's fill factor, promote infrared absorption efficiency, realize infrared thermopile sensor's miniaturization.
Drawings
To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description will be given below of the drawings required for the embodiments or the technical solutions in the prior art, and it is obvious that the drawings in the following description, although being some specific embodiments of the present invention, can be extended and extended to other structures and drawings by those skilled in the art according to the basic concepts of the device structure, the driving method and the manufacturing method disclosed and suggested by the various embodiments of the present invention, without making sure that these should be within the scope of the claims of the present invention.
Fig. 1 is a schematic structural diagram of an infrared thermopile pixel according to an embodiment of the present invention;
FIG. 2 is a cross-sectional view along AA of an infrared thermopile sensor provided in accordance with an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of an infrared thermopile sensor chip according to an embodiment of the present invention;
FIG. 4 is a schematic flow chart of a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention;
FIG. 5 is a schematic flow chart of another method for fabricating an infrared thermopile sensor in accordance with an embodiment of the present invention;
fig. 6 is a schematic view of a manufacturing process of an infrared thermopile sensor according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described through embodiments with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the basic idea disclosed and suggested by the embodiments of the present invention, are within the scope of the present invention.
Fig. 1 is a schematic structural diagram of an infrared thermopile pixel according to an embodiment of the present invention, and as shown in fig. 1, the infrared thermopile sensor includes a plurality of infrared thermopile pixels, and the infrared thermopile pixels include:
a substrate 100, the substrate 100 comprising a first region 101 and a second region 102, the second region 102 surrounding the first region 101;
a first suspended film 103 located on the substrate 100 side and located in the first region 101 and a second suspended film 104 located on the substrate 100 side and located in the second region 102;
a thermopile structure 105 and a switch circuit 106 located on a side of the first suspended membrane 103 away from the substrate 100, the thermopile structure 105 including an N-type thermopile 1051 and a P-type thermopile 1052, the switch circuit 106 being located between the N-type thermopile 1051 and the P-type thermopile 1052;
a cantilever beam 107 located on a side of the second flying film 104 away from the substrate 100 and a switching signal derivation structure 108, the switching signal derivation structure 108 being electrically connected to the switching circuit 106.
Among them, the infrared thermopile sensor is a temperature measuring element for measuring a small temperature difference or an average temperature, and has been widely used in the fields of ear thermometers, radiation thermometers, electric ovens, food temperature detection, and the like. The substrate comprises a first area 101 and a second area 102, and a first suspended film 103 positioned in the first area 101 and a second suspended film 104 positioned in the second area 102. the second suspended film 103 are used for absorbing infrared radiation emitted by a measured object and converting the infrared radiation into heat energy. The thermopile structure 105 located on the side of the first suspended membrane 103 remote from the substrate 100 converts thermal energy into an electrical signal using the seebeck effect. The cantilever beam 107 on the side of the second suspended membrane 104 away from the substrate 100 is used to retain most of the thermal energy on the first suspended membrane 103 and the second suspended membrane 103 without being dissipated, thereby playing a certain role of thermal insulation and mechanical support. The thermopile structure 105 is composed of two or more thermocouples connected in series, the thermoelectric potentials output by the thermocouples are mutually superimposed, and the thermocouples mainly include semiconductor thermocouples and metal thermocouples. As shown in fig. 1, the exemplary depicted thermopile structure includes an N-type thermopile 1051 and a P-type thermopile 1052, and the switching circuit 106 may be of the type MOS transistor switching circuit for gating infrared thermopile pixels. Compare and adopt planar mode of arranging in traditional infrared thermopile sensor, set up MOS transistor switch circuit at the edge of infrared thermopile structure, occupy certain area, when the infrared radiation that the object sent actually awaits measuring gets into infrared thermopile sensor, must be at the unable absorption infrared radiation of MOS transistor switch circuit area-occupied part, thereby make the absorption efficiency step-down of infrared thermopile sensor, infrared thermopile sensor's fill factor can not be very high, sensitivity can not effectively be promoted, can influence the precision of two-dimensional plane formation of image and temperature measurement among the practical application. And the switching circuit 106 is located between the N-type thermopile 1051 and the P-type thermopile 1052 on the side of the first suspended film 103 away from the substrate 100. When receiving the infrared radiation that the object to be measured launched, MOS transistor switch circuit part also can improve the absorption to the infrared radiation signal as infrared absorption layer owing to be in on first suspended film 103, simultaneously because whole infrared thermopile sensor is except necessary metal wire part, just does not have other invalid absorption areas for infrared thermopile sensor's fill factor becomes very high, promotes absorption efficiency greatly. In addition, the high-density structural design also reduces the area of the infrared thermopile sensor, reduces the manufacturing cost and is suitable for miniaturized application.
According to the technical scheme, the infrared thermopile sensor is arranged between the N-type thermopile and the P-type thermopile of the thermopile structure through the switch structure and is positioned on one side, far away from the substrate, of the first suspension film, so that the occupied area of a switch circuit in the plane of the infrared array sensor is effectively avoided, the area for ineffective absorption of infrared radiation is reduced, the filling factor of the infrared thermopile sensor is effectively improved, and the detection sensitivity is improved.
Optionally, cantilever beam 107 includes a first cantilever beam 1071 and a second cantilever beam 1072;
the first cantilever beam 1071 is respectively and electrically connected with the N-type thermopile 1051 and the first metal contact hole 109 to form a cold end signal transmission path of the infrared thermopile sensor;
the second cantilever beam 1072 is electrically connected to the P-type thermopile 1052 and the second metal contact hole 110, respectively, to form a hot side signal transmission path of the infrared thermopile sensor.
Wherein, N type electric pile 1051 can be called the cold junction, and N type electric pile 1051 is connected with first metal contact hole 109 electricity through first cantilever beam 1071, forms infrared thermopile sensor's cold junction signal transmission route and reference signal connecting wire, guarantees the normal transmission of cold junction signal, and the reference signal of infrared thermopile sensor also can be regarded as to the cold junction signal for the bias voltage of infrared thermopile pixel in the modulation infrared thermopile sensor. The P-type thermopile 1052 may be referred to as a hot end, the P-type end of the P-type thermopile 1052 is electrically connected to the second metal contact hole 110 through the second cantilever beam 1072 to form a hot end signal transmission path of the infrared thermopile sensor, thereby ensuring normal transmission of a hot end signal, and the second cantilever beam 1072 is electrically connected to the source 1061 of the switching circuit 106, thereby ensuring voltage control of the source 1061 of the switching circuit 106. Meanwhile, the cantilever beam 107 plays a role of thermal insulation and mechanical support for the infrared thermopile sensor, so that the infrared radiation heat absorbed by the object to be measured is retained to the maximum extent and is not scattered to the periphery, and the thermopile structure 105 is converted to obtain a higher electric signal.
Optionally, the switch circuit 106 includes a source 1061, a gate 1062, a drain 1063, and a ground hole 1064;
the switch signal deriving structure 108 includes a source connection line 1081, a gate connection line 1082, a drain connection line 1083 and a ground connection line 1084;
the source connecting line 1081 is electrically connected to the second metal contact hole 110 and the source 1061, respectively, to form an input signal transmission path of the switch circuit 106;
the gate connection line 1082 is electrically connected to the switching signal connection line 11 and the gate 1062, respectively, to form a switching signal transmission path of the switching circuit 106;
the drain connecting line 1083 is electrically connected to the output signal receiving terminal and the drain 1063, respectively, to form an output signal transmission path of the switch circuit 106;
the ground connection line 1084 is electrically connected to the ground signal terminal and the ground hole 1064, respectively, to form a ground signal transmission path of the switch circuit 106.
The drain connecting line 1083 is electrically connected to the output signal receiving terminal and the drain 1063, respectively, to form an output signal transmission path of the switch circuit 106 and the output signal connecting line 12. The ground connection line 1084 is electrically connected to the ground signal terminal and the ground hole 1064, respectively, and forms the ground signal transmission path and the ground line 13 of the switch circuit 106. The N-type thermopile 1051, P-type thermopile 1052, gate 1062, and switching signal connection 11 may all be polycrystalline materials, such as polysilicon. The source 1061, the drain 1063, the source connecting line 1081, the gate connecting line 1082, the ground connecting line 1084, the reference signal connecting line 11, the output signal connecting line 12, and the ground line 13 may be made of a metal material, such as aluminum, copper, or the like. The contact part of the polycrystalline material and the metal material enables the polycrystalline material and the metal material to be isolated by an insulating layer and not connected, so that the polycrystalline material and the metal material can be arranged in an up-down laminated mode and further connected through the first metal hole 109, the second metal hole 110 and the like to form an electric path.
Optionally, a vertical projection of the source connecting line 1081 located in the second region 102 on the plane of the substrate 100 overlaps with a vertical projection of the second cantilever beam 1072 on the plane of the substrate 100;
the perpendicular projection of the ground connection line 1084 located at the second region 102 onto the plane of the substrate 100 overlaps the perpendicular projection of the first cantilever beam 1071 onto the plane of the substrate 100.
The vertical projection of the source connecting line 1081 on the plane of the substrate 100 is overlapped with the vertical projection of the second cantilever beam 1072 on the plane of the substrate 100, and the vertical projection of the ground connecting line 1084 on the plane of the substrate 100 is overlapped with the vertical projection of the first cantilever beam 1071 on the plane of the substrate 100, and the vertical projection and the ground connecting line 1084 are arranged in an up-and-down laminated mode, so that the occupied area of the source connecting line 1081 and the ground connecting line 1084 on the plane of the infrared thermopile sensor can be effectively reduced, the manufacturing cost of the infrared thermopile sensor is reduced, and the miniaturization is realized.
Optionally, the N-type thermopile 1051, the P-type thermopile 1052, the gate 1062, and the gate connection line 1082 are disposed in the same layer;
the source 1061, the drain 1063, the ground hole 1064, the source connection line 1081, the drain connection line 1083, and the ground connection line 1084 are disposed in the same layer.
The N-type thermopile 1051, the P-type thermopile 1052, the gate 1062, and the gate connection line 1082 are disposed in the same layer, so as to reduce the process flow and the cost. Similarly, the source 1061, the drain 1063, the ground hole 1064, the source connection line 1081, the drain connection line 1083, and the ground connection line 1084 are disposed in the same layer under the condition that the infrared thermopile sensor can be used normally, which is also beneficial to reducing the manufacturing cost.
Fig. 2 is a cross-sectional view along AA of an infrared thermopile sensor according to an embodiment of the present invention, as shown in fig. 2, and optionally, the infrared thermopile sensor further includes an N-well region 111 and a P-well region 112;
the N-well region 111 and the P-silicon region 112 are located between the first suspended film 103 and the substrate 100, and the P-well region 112 is located within the N-well region 111.
The material of the substrate 100 may be silicon, the N-well region 111 and the P-silicon region 112 may be etched by using MEMS silicon etching technology, according to anisotropic etching characteristics of silicon, the etching rate may be suppressed due to heavy doping, the selected pre-formed N-well region is heavily doped, a phenomenon of silicon etching self-termination is formed by doping a certain amount of boron ions, and the heavily doped region is retained in the N-well region 111 after etching. The selected pre-formed P-well region is further heavily doped, which may be doped with a certain dose of phosphorus ions, to finally form a P-well silicon region 112 in the heavily doped region. The formed N-well region 111 and P-silicon region 112 are located between the first suspended film 103 and the substrate 100, and the P-well region 112 is located in the N-well region 111, so that the formed switch circuit 106 can still operate effectively, and the infrared thermopile sensor can also operate normally.
Optionally, N-type thermopile 1051 and P-type thermopile 1052 are electrically connected through third metal contact hole 113.
Wherein, thermopile structure 105 on the first suspended membrane 103 is divided into N-type thermopile 1051 and P-type thermopile 1052, and N-type thermopile 1051 and P-type thermopile 1052 utilize third metal contact hole 113 to electrically connect, realize that N-type thermopile 1051 and P-type thermopile 1052 are connected in series, and the thermoelectric force of each thermopile output is superimposed each other, and infrared thermopile sensor strengthens the detection ability of the object to be detected.
Fig. 3 is a schematic structural diagram of an infrared thermopile sensor chip according to an embodiment of the present invention, and as shown in fig. 3, the infrared thermopile sensor chip 200 includes a plurality of infrared thermopile sensors 201;
a plurality of the infrared thermopile sensors 201 are arrayed.
Wherein, the size of infrared thermopile sensor chip 200 can be 10um ~ 1mm, can make the infrared thermopile sensor chip 200 of different sizes according to actual need.
The infrared thermopile sensor chip provided by the embodiment of the present invention may execute the infrared thermopile sensor provided by the above embodiments of the present invention, and has the same or corresponding functional modules and beneficial effects, which are not described herein in detail.
Fig. 4 is a schematic flow chart of a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention, as shown in fig. 4, for manufacturing the infrared thermopile sensor according to any one of the foregoing embodiments, the method includes:
s101, providing a substrate.
The material of the substrate 100 may be monocrystalline silicon, the shape of the substrate 100 may be selected according to actual requirements, and may be square or rectangular, and the material and the shape of the substrate 100 are not specifically limited in the embodiments of the present invention.
S102, preparing a first oxidation layer on one side of the substrate, wherein the first oxidation layer comprises a first area, a second area, a first interval area positioned between the first area and the second area, and a second interval area positioned on one side of the second area far away from the first area.
The first oxide layer 301 may be made of silicon nitride, silicon oxynitride, phosphosilicate glass, borophosphosilicate glass, or the like, and may be prepared by using processes such as silicon nitride growth deposition, silicon selective oxidation process, phosphosilicate glass deposition, borophosphosilicate glass deposition, or silicon oxide silicon nitride passivation layer, or the like. The first oxide layer 301 has a thickness of 10nm to 10000nm, and functions to filter impurity particles and function as a gate oxide layer.
S103, preparing a thermopile structure and a switch circuit on one side of the first oxidation layer far away from the substrate in a first area, and preparing a cantilever beam and a switch signal leading-out structure on one side of the first oxidation layer far away from the substrate in a second area; the thermopile structure comprises an N-type thermopile and a P-type thermopile, the switching circuit is positioned between the N-type thermopile and the P-type thermopile, and the switching signal derivation structure is electrically connected with the switching circuit.
S104, etching the substrate in the first interval area and the second interval area to form a cavity; the first oxide layer on the surface of the cavity and in the first region is a first suspended film, and the first oxide layer on the surface of the cavity and in the second region is a second suspended film.
The formation of the cavity 302 may be performed by wet etching, for example, by using a KOH solution or a TMAH solution, and the existence of the cavity 302 may ensure that the heat of the absorbed infrared radiation is gathered on the first suspended film 103 and the second suspended film 104, so as to store the heat.
Fig. 5 is a schematic flow chart of another method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention, and fig. 6 is a schematic flow chart of a method for manufacturing an infrared thermopile sensor according to an embodiment of the present invention, as shown in fig. 5 and 6, with continued reference to fig. 1 and 2, optionally, the cantilever beam 107 includes a first cantilever beam 1071 and a second cantilever beam 1072;
the switch circuit 106 includes a source 1061, a gate 1062, a drain 1063, and a ground hole 1064;
the switch signal deriving structure 108 includes a source connection line 1081, a gate connection line 1082, a drain connection line 1083 and a ground connection line 1084;
the infrared thermopile sensor further includes an N-well region 111 and a P-well region 112; the N-well region 111 and the P-well region 112 are located between the first suspended film 103 and the substrate 100, and the P-well region 112 is located within the N-well region 111;
preparing the thermopile structure 105 and the switching circuit 106 on the side of the first oxide layer 301 away from the substrate 100 and in the first region 101, preparing the cantilever beam 107 and the switching signal deriving structure 108 on the side of the first oxide layer 301 away from the substrate 100 and in the second region 102, comprising:
s201, providing a substrate.
S202, preparing a first oxidation layer on one side of the substrate, wherein the first oxidation layer comprises a first region, a second region, a first interval region positioned between the first region and the second region, and a second interval region positioned on one side of the second region far away from the first region.
And S203, carrying out N-type doping on the substrate by utilizing the CMOS photoetching development technology to form an N-well region.
Firstly, cleaning the surface of the substrate by utilizing the CMOS photoetching development technology, removing impurities, coating photoresist 14 on other areas where the N-shaped well region is removed, heavily doping the N-shaped well region, injecting boron ions with a certain dosage by adopting an NPLUS injection process, wherein the doping concentration of the N-shaped well region is 1 x 105～1*1020cm-3After the N-well region is formed, the photoresist 14 is removed.
And S204, performing P-type doping on the N-well region by utilizing the CMOS photoetching development technology to form a P-well region.
Wherein, P-well region 112 is located in N-well region 111, P-well region 112 can be prepared by the same CMOS photoetching development technology as that of N-well region, coating photoresist 14 on other regions except the pre-formed P-well region, heavily doping the pre-formed P-well region, injecting phosphorus ions with a certain dosage by PPLUS injection process, the doping concentration of the pre-formed P-well region is 1 × 105～1*1020cm-3After the P-well region is formed, the photoresist 14 is removed.
S205, preparing a polysilicon layer on the side of the first oxide layer far away from the substrate, and etching the polysilicon layer to form an N-type thermopile, a P-type thermopile, a grid and a grid connecting line.
S206, preparing a second oxide layer on one side of the polycrystalline silicon layer far away from the substrate, and etching the first oxide layer and the second oxide layer by utilizing a CMOS photoetching development technology to form a source electrode contact hole, a drain electrode contact hole, a first metal contact hole and a second metal contact hole.
The source contact hole 15, the drain contact hole 16, the first metal contact hole 109 and the second metal contact hole 110 are formed by using a CMOS photolithography and development technology according to actual shape and size requirements.
And S207, preparing a metal layer on one side of the second oxide layer, which is far away from the substrate, and forming a source electrode, a drain electrode, a source electrode signal wire, a drain electrode connecting wire and a grounding wire.
And S208, etching the first oxide layer and the second oxide layer in the first interval region and the second interval region to form corrosion holes.
S209, etching the substrate by using the etching hole to form a cantilever beam, a first suspended film, a second suspended film and a cavity.
The thickness ranges of the polysilicon layer 303 and the metal layer 305 are both 100 nm-1000 nm, which is beneficial to reducing the difficulty of the manufacturing process. The second oxide layer 304 may be made of silicon nitride, silicon oxynitride, phosphorosilicate glass, borophosphosilicate glass, or the like, the thickness of the second oxide layer 304 is 10nm to 1000nm, and the second oxide layer 304 plays a role of electrical insulation to prevent a short circuit caused by direct contact between the polysilicon layer 303 and the metal layer 305. And the thickness and the material of the first oxide layer 301 and the second oxide layer 304 can be set to be the same, which is beneficial to reducing the difficulty of the manufacturing process and the processing cost. The etch hole 306 is formed by etching the first oxide layer and the second oxide layer in the first spacer region and the second spacer region, and a KOH solution or a TMAH solution for wet etching is injected through the etch hole 306 to etch and form the cavity 302. In the embodiment of the present invention, the infrared thermopile sensor is exemplarily prepared by using a CMOS 1P1M process, and is applicable to a CMOS 1P1M process used in an embodiment, and is also applicable to 1P2M, 2P2M, 2P3M, 2P5M processes, and the like, and the processes can be selected according to actual needs of the infrared thermopile sensor preparation, which is not specifically limited in the present invention.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (10)

1. An infrared thermopile sensor comprising a plurality of infrared thermopile pixels, said infrared thermopile pixels comprising:
a substrate comprising a first region and a second region, the second region surrounding the first region;
the first suspended film is positioned on one side of the substrate and positioned in the first area, and the second suspended film is positioned on one side of the substrate and positioned in the second area;
the thermopile structure and the switch circuit are positioned on one side, far away from the substrate, of the first suspended film, the thermopile structure comprises an N-type thermopile and a P-type thermopile, and the switch circuit is positioned between the N-type thermopile and the P-type thermopile;
the cantilever beam and the switching signal derivation structure are positioned on one side, far away from the substrate, of the second suspension film, and the switching signal derivation structure is electrically connected with the switching circuit.
2. The infrared thermopile sensor of claim 1, wherein the cantilevered beams include a first cantilevered beam and a second cantilevered beam;
the first cantilever beam is respectively and electrically connected with the N-type thermopile and the first metal contact hole to form a cold end signal transmission path of the infrared thermopile sensor;
and the second cantilever beam is respectively and electrically connected with the P-type thermopile and the second metal contact hole to form a hot end signal transmission path of the infrared thermopile sensor.
3. The infrared thermopile sensor of claim 2, wherein the switching circuit includes a source, a gate, a drain, and a ground via;
the switch signal leading-out structure comprises a source electrode connecting wire, a grid electrode connecting wire, a drain electrode connecting wire and a grounding connecting wire;
the source electrode connecting wire is electrically connected with the second metal contact hole and the source electrode respectively to form an input signal transmission path of the switch circuit;
the grid connecting line is electrically connected with the switch signal connecting line and the grid respectively to form a switch signal transmission path of the switch circuit;
the drain electrode connecting wire is respectively and electrically connected with an output signal receiving end and the drain electrode to form an output signal transmission path of the switch circuit;
the grounding connecting line is electrically connected with the grounding signal end and the grounding hole respectively to form a grounding signal transmission path of the switch circuit.
4. The infrared thermopile sensor of claim 3, wherein a perpendicular projection of the source connection line at the second region onto the plane of the substrate overlaps a perpendicular projection of the second cantilevered beam onto the plane of the substrate;
the vertical projection of the ground connection line on the plane of the substrate in the second area is overlapped with the vertical projection of the first cantilever beam on the plane of the substrate.
5. The infrared thermopile sensor of claim 3, wherein the N-type thermopile, the P-type thermopile, the gate, and the gate connection line are disposed in the same layer;
the source electrode, the drain electrode, the grounding hole, the source electrode connecting wire, the drain electrode connecting wire and the grounding connecting wire are arranged on the same layer.
6. The infrared thermopile sensor of claim 1, further comprising an N-well region and a P-well region;
the N-well region and the P-silicon region are located between the first suspended film and the substrate, and the P-well region is located in the N-well region.
7. The infrared thermopile sensor of claim 1, wherein the N-type thermopile and the P-type thermopile are electrically connected through a third metal contact hole.
8. An infrared thermopile sensor chip comprising a plurality of infrared thermopile sensors of any one of claims 1-7;
and a plurality of infrared thermopile sensor arrays are arranged.
9. A method for manufacturing an infrared thermopile sensor according to any one of claims 1-7, said method comprising:
providing a substrate;
preparing a first oxidation layer on one side of the substrate, wherein the first oxidation layer comprises a first region, a second region, a first spacing region positioned between the first region and the second region, and a second spacing region positioned on one side, far away from the first region, of the second region;
preparing a thermopile structure and a switching circuit on one side of the first oxidation layer far away from the substrate and in the first area, and preparing a cantilever beam and a switching signal leading-out structure on one side of the first oxidation layer far away from the substrate and in the second area; the thermopile structure comprises an N-type thermopile and a P-type thermopile, the switching circuit is positioned between the N-type thermopile and the P-type thermopile, and the switching signal derivation structure is electrically connected with the switching circuit;
etching the substrate in the first interval region and the second interval region to form a cavity; the first oxide layer located on the surface of the cavity and in the first area is a first suspended film, and the first oxide layer located on the surface of the cavity and in the second area is a second suspended film.
10. The infrared thermopile sensor of claim 9, wherein the cantilevered beams include a first cantilevered beam and a second cantilevered beam;
the switch circuit comprises a source electrode, a grid electrode, a drain electrode and a grounding hole;
the switch signal leading-out structure comprises a source electrode connecting wire, a grid electrode connecting wire, a drain electrode connecting wire and a grounding connecting wire;
the infrared thermopile sensor further comprises an N-well region and a P-well region; the N-well region and the P-well region are positioned between the first suspended film and the substrate, and the P-well region is positioned in the N-well region;
preparing a thermopile structure and a switching circuit on a side of the first oxide layer away from the substrate and in the first region, and thermally preparing a cantilever beam and a switching signal deriving structure on a side of the first oxide layer away from the substrate and in the second region, comprising:
carrying out N-type doping on the substrate by utilizing a CMOS photoetching development technology to form an N-well region;
performing P-type doping on the N-well region by utilizing a CMOS photoetching development technology to form a P-well region;
preparing a polysilicon layer on one side of the first oxidation layer, which is far away from the substrate, and etching the polysilicon layer to form the N-type thermopile, the P-type thermopile, the grid and the grid connecting line;
preparing a second oxide layer on one side of the polycrystalline silicon layer, which is far away from the substrate, and etching the first oxide layer and the second oxide layer by utilizing a CMOS photoetching development technology to form a source contact hole, a drain contact hole, a first metal contact hole and a second metal contact hole;
preparing a metal layer on one side of the second oxide layer, which is far away from the substrate, and forming the source electrode, the drain electrode, the source electrode signal wire, the drain electrode connecting wire and the grounding wire;
etching the first oxide layer and the second oxide layer in the first interval area and the second interval area to form an etching hole;
and etching the substrate by using the etching hole to form the cantilever beam, the first suspended film, the second suspended film and the cavity.
CN202110389130.9A 2021-04-12 2021-04-12 Infrared thermopile sensor, chip and preparation method thereof Pending CN113104804A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115876835A (en) * 2022-12-08 2023-03-31 中国科学院上海微***与信息技术研究所 Differential thermal MEMS (micro-electromechanical systems) gas sensor and gas detection method

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115876835A (en) * 2022-12-08 2023-03-31 中国科学院上海微***与信息技术研究所 Differential thermal MEMS (micro-electromechanical systems) gas sensor and gas detection method
CN115876835B (en) * 2022-12-08 2023-09-08 中国科学院上海微***与信息技术研究所 Differential calorimetric MEMS gas sensor and gas detection method

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