CN113720475B

CN113720475B - Infrared detector mirror image element based on CMOS (complementary metal oxide semiconductor) process and infrared detector

Info

Publication number: CN113720475B
Application number: CN202110324034.6A
Authority: CN
Inventors: 翟光杰; 武佩; 潘辉; 翟光强
Original assignee: Beijing North Gaoye Technology Co ltd
Current assignee: Beijing North Gaoye Technology Co ltd
Priority date: 2021-03-26
Filing date: 2021-03-26
Publication date: 2023-01-06
Anticipated expiration: 2041-03-26
Also published as: CN113720475A

Abstract

The present disclosure relates to an infrared detector mirror image element and an infrared detector based on CMOS process, the mirror image element includes: the CMOS measuring circuit system and the CMOS infrared sensing structure are both prepared by using a CMOS process, and the CMOS infrared sensing structure is directly prepared above the CMOS measuring circuit system; the CMOS infrared conversion structure comprises a reflecting layer, an infrared conversion structure and a first columnar structure, wherein the reflecting layer comprises a reflecting plate and a supporting base, and the infrared conversion structure is electrically connected with the CMOS measurement circuit system through the first columnar structure and the supporting base; the beam structure is located on one side, close to the CMOS measuring circuit system, of the absorption plate, the CMOS infrared conversion structure further comprises a patterned metal structure arranged corresponding to the beam structure, and at least part of the reflection plate is located in the orthographic projection of the patterned metal structure. Through the technical scheme, the problems of low performance, low pixel scale, low yield and the like of the traditional MEMS process infrared detector are solved.

Description

Infrared detector mirror image element based on CMOS (complementary metal oxide semiconductor) process and infrared detector

Technical Field

The disclosure relates to the technical field of infrared detection, in particular to an infrared detector mirror image pixel based on a CMOS (complementary metal oxide semiconductor) process and an infrared detector.

Background

The fields of monitoring markets, vehicle and auxiliary markets, home markets, intelligent manufacturing markets, mobile phone applications and the like have strong demands on uncooled high-performance chips, certain requirements are provided for the performance of the chips, the performance consistency and the product price, the potential demands of more than one hundred million chips are expected every year, and the current process scheme and architecture cannot meet the market demands.

At present, an infrared detector adopts a mode of combining a measuring circuit and an infrared sensing structure, the measuring circuit is prepared by adopting a Complementary Metal-Oxide-Semiconductor (CMOS) process, and the infrared sensing structure is prepared by adopting a Micro-Electro-Mechanical System (MEMS) process, so that the following problems are caused:

(1) The infrared sensing structure is prepared by adopting an MEMS (micro-electromechanical systems) process, polyimide is used as a sacrificial layer, and the infrared sensing structure is incompatible with a CMOS (complementary metal oxide semiconductor) process.

(2) Polyimide is used as a sacrificial layer, so that the problem that the vacuum degree of a detector chip is influenced due to incomplete release exists, the growth temperature of a subsequent film is limited, and the selection of materials is not facilitated.

(3) Polyimide can cause the height of the resonant cavity to be inconsistent, and the working dominant wavelength is difficult to ensure.

(4) The control of the MEMS process is far worse than that of the CMOS process, and the performance consistency and the detection performance of the chip are restricted.

(5) MEMS has low capacity, low yield and high cost, and can not realize large-scale batch production.

(6) The existing process capability of the MEMS is not enough to support the preparation of a detector with higher performance, and the MEMS has smaller line width and thinner film thickness, so that the miniaturization of a chip is not facilitated.

The infrared detector has the working principle that infrared radiation signals are absorbed, the absorption of the infrared radiation signals causes the change of temperature, the change of the resistance value of the infrared detector is caused by the change of the temperature, and the size of the infrared radiation signals is detected by measuring the change of the resistance value. During the operation of the infrared detector, substrate noise, background noise, noise generated by self-heating, and the like may be introduced, which affects the accuracy of the detection result of the infrared detector.

In the prior art, a mirror image pixel is arranged in an infrared detector, and a noise signal of the infrared detector is acquired through the mirror image pixel, so that a detection signal after noise reduction is obtained, and the accuracy of a detection result is improved. However, a pixel structure capable of acquiring a noise signal is not disclosed at present.

Disclosure of Invention

In order to solve the technical problem or at least partially solve the technical problem, the disclosure provides an infrared detector mirror image pixel and an infrared detector.

In a first aspect, an embodiment of the present disclosure provides an infrared detector mirror image pixel based on a CMOS process, including:

the CMOS infrared sensing structure comprises a CMOS measuring circuit system and a CMOS infrared sensing structure, wherein the CMOS measuring circuit system and the CMOS infrared sensing structure are both prepared by using a CMOS process, and the CMOS infrared sensing structure is directly prepared above the CMOS measuring circuit system;

the CMOS manufacturing process of the CMOS infrared sensing structure comprises a metal interconnection process, a through hole process and an RDL (remote data link) process, wherein the CMOS infrared sensing structure comprises at least two metal interconnection layers, at least two dielectric layers and a plurality of interconnection through holes;

the CMOS infrared sensing structure comprises a reflecting layer, an infrared conversion structure and a plurality of first columnar structures, wherein the reflecting layer, the infrared conversion structure and the plurality of first columnar structures are positioned on the CMOS measuring circuit system, the first columnar structures are positioned between the reflecting layer and the infrared conversion structure, the reflecting layer comprises a reflecting plate and a supporting base, and the infrared conversion structure is electrically connected with the CMOS measuring circuit system through the first columnar structures and the supporting base;

the infrared conversion structure comprises an absorption plate and a plurality of beam structures, the beam structures are positioned on one side, close to the CMOS measurement circuit system, of the absorption plate, second columnar structures are arranged between the absorption plate and the beam structures, and the absorption plate is used for converting infrared signals into electric signals and is electrically connected with the corresponding first columnar structures through the second columnar structures and the corresponding beam structures;

the CMOS infrared sensing structure further comprises a patterned metal structure arranged corresponding to the beam structure, and at least part of the reflecting plate is located in an orthographic projection area of the patterned metal structure.

Optionally, the patterned metal structure is located in a hollow region between the beam structures.

Optionally, the patterned metal structure is disposed in a same layer as the beam structure.

Optionally, the beam structure comprises a first electrode layer and a passivation layer, the first electrode layer is located on a side of the passivation layer adjacent to the CMOS measurement circuitry;

the patterned metal structure is located on one side, far away from the first electrode layer, of the passivation layer and is in contact with the passivation layer, and the pattern of the patterned metal structure is consistent with that of the beam structure.

Optionally, the beam structure comprises a first electrode layer, the absorber plate comprises a second electrode layer and a heat sensitive layer, the second electrode layer is electrically connected with the first electrode layer through the second columnar structure, and the first electrode layer is electrically connected with the first columnar structure.

Optionally, the sacrificial layer is used for enabling the CMOS infrared sensing structure to form a hollow structure, the material forming the sacrificial layer is silicon oxide, and the sacrificial layer is etched by using at least one of gas-phase hydrogen fluoride, carbon tetrafluoride and trifluoromethane.

Optionally, the beam structures are respectively connected to a middle support structure and the first columnar structure, and in the beam paths from the middle support structure to the corresponding first columnar structure, two parallel beam structures meeting at the same node are respectively a first half-bridge structure and a second half-bridge structure, where the first half-bridge structure and the second half-bridge structure form a thermally symmetric structure; wherein the length of the first half-bridge structure is greater than the length of the second half-bridge structure, and the thickness of the first half-bridge structure is greater than the thickness of the second half-bridge structure in a direction perpendicular to the CMOS measurement circuitry.

Optionally, the CMOS infrared sensing structure further includes at least one hermetic release insulating layer on the reflective layer, where the hermetic release insulating layer is used to protect the CMOS measurement circuit system from process influence during an etching process for manufacturing the CMOS infrared sensing structure, and the hermetic release insulating layer covers the first columnar structure.

Optionally, the material constituting the hermetic release barrier layer includes at least one of silicon, germanium, silicon germanium, amorphous carbon, silicon carbide, aluminum oxide, or silicon nitride.

In a second aspect, the present disclosure provides an infrared detector based on a CMOS process, which includes any one of the infrared detector mirror image elements based on a CMOS process as provided in the first aspect.

Optionally, the beam structure includes a first electrode layer and a passivation layer, the first electrode layer is located on a side of the passivation layer adjacent to the CMOS measurement circuitry, the patterned metal structure is located on a side of the passivation layer away from the first electrode layer and is in contact with the passivation layer, and the patterned metal structure is in accordance with a pattern of the beam structure;

the infrared detector further comprises an infrared detector effective pixel, and the length of the beam structure of the infrared detector mirror image pixel is larger than that of the beam structure of the infrared detector effective pixel.

Compared with the prior art, the technical scheme provided by the disclosure has the following advantages:

(1) The infrared conversion structure comprises an absorption plate and a plurality of beam structures, the beam structures are positioned on one side, close to a CMOS (complementary metal oxide semiconductor) measurement circuit system, of the absorption plate, second columnar structures are arranged between the absorption plate and the beam structures, the absorption plate is used for converting infrared signals into electric signals and is electrically connected with corresponding first columnar structures through the second columnar structures and the corresponding beam structures, the absorption plate and the beam structures are arranged on different layers, the area of the beam structures cannot affect the area of the absorption plate, the absorption plate with a larger area is beneficial to realization, the radiation absorption capacity of mirror image pixels of the infrared detector can be improved, more accurate noise signals can be obtained, and the detection performance of the infrared detector can be improved. In addition, the size of the mirror image pixel structure of the infrared detector is not limited by the sum of the area of the absorption plate and the area of the beam structure any more, the size of the mirror image pixel of the infrared detector can be reduced, and the development of the infrared detector towards miniaturization is facilitated.

(2) Through the patterning metal structure that CMOS infrared sensing structure set up including corresponding beam structure, at least partial reflecting plate is located patterning metal structure's orthographic projection region, the infrared light that sees through the absorption plate takes place the reflection on beam structure's surface, the reflecting plate can not reflect the infrared light, the height of the resonant cavity between CMOS measurement circuitry and the absorption plate has been changed promptly, make the resonant cavity no longer satisfy the resonance condition of infrared light, so can not produce resonance light in the resonant cavity, at this moment, the signal of telecommunication that the absorption plate produced is from temperature noise, therefore, can acquire infrared detector's noise signal through the mirror image pixel, can acquire more accurate detection signal according to this, thereby improve the accuracy of detection result.

(3) The embodiment of the invention realizes the integrated preparation of the CMOS measuring circuit system and the CMOS infrared sensing structure on the CMOS production line by utilizing the CMOS process, compared with the MEMS process, the CMOS has no process compatibility problem, the technical difficulty of the MEMS process is solved, and the transportation cost and the risk caused by the problems of transportation and the like can be reduced by adopting the CMOS process production line process to prepare the infrared detector; the infrared detector takes silicon oxide as a sacrificial layer, the silicon oxide is completely compatible with a CMOS (complementary metal oxide semiconductor) process, the preparation process is simple and easy to control, the CMOS process does not have the problem that the polyimide of the sacrificial layer is not released cleanly to influence the vacuum degree of a detector chip, the subsequent film growth temperature is not limited by the material of the sacrificial layer, the multilayer process design of the sacrificial layer can be realized, the process is not limited, the planarization can be easily realized by using the sacrificial layer, and the process difficulty and the possible risks are reduced; the infrared detector prepared by the integrated CMOS process can realize the aims of high yield, low cost, high yield and large-scale integrated production of chips, and provides a wider application market for the infrared detector; the infrared detector based on the CMOS process can realize smaller size and thinner film thickness of a characteristic structure, so that the infrared detector has larger duty ratio, lower thermal conductivity and smaller thermal capacity, and the infrared detector has higher detection sensitivity, longer detection distance and better detection performance; the infrared detector based on the CMOS process can make the pixel size of the detector smaller, realize smaller chip area under the same array pixel, and is more beneficial to realizing the miniaturization of a chip; the infrared detector based on the CMOS process has the advantages of mature process production line, higher process control precision, better meeting design requirements, better product consistency, more contribution to circuit chip adjustment performance and more contribution to industrialized mass production.

(4) The patterned metal structure is arranged corresponding to the beam structure, the patterned metal structure is located on one side, close to the CMOS measuring circuit system, of the absorption plate, namely the patterned metal structure is formed before the effective pixel is prepared, so that the process can be increased, the effective pixel and the mirror image pixel are prepared simultaneously by matching with a corresponding mask, the patterned metal structure is added in the mirror image pixel, the structure of the effective pixel is not changed, synchronous preparation of the two pixel structures is achieved, and the process flow of the infrared detector is simplified.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.

In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present disclosure, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

Fig. 1 is a schematic perspective view of a mirror image pixel of an infrared detector based on a CMOS process according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a CMOS measurement circuit system according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a film structure of a mirror image pixel of an infrared detector based on a CMOS process according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a film structure of another infrared detector mirror image pixel based on a CMOS process according to an embodiment of the present invention;

fig. 5 is a schematic diagram of a film structure of another infrared detector mirror image pixel based on a CMOS process according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a beam structure according to an embodiment of the present invention;

FIG. 7 is a schematic perspective view of another imaging pixel of an infrared detector based on a CMOS process according to an embodiment of the present invention;

fig. 8 is a schematic perspective view of a mirror image pixel of another infrared detector based on a CMOS process according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a film structure of a mirror image pixel of an infrared detector based on a CMOS process according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a film structure of a mirror image pixel of an infrared detector based on a CMOS process according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of a film structure of a mirror image pixel of an infrared detector based on a CMOS process according to an embodiment of the present invention;

FIG. 12 is a schematic diagram of a film structure of a mirror image pixel of an infrared detector based on a CMOS process according to an embodiment of the present invention;

FIG. 13 is a schematic diagram of a film structure of a mirror image pixel of an infrared detector based on a CMOS process according to an embodiment of the present invention;

FIG. 14 is a schematic diagram of a film structure of a mirror image pixel of an infrared detector based on a CMOS process according to an embodiment of the present invention;

fig. 15 is a schematic perspective view of an infrared detector based on a CMOS process according to an embodiment of the present invention.

Detailed Description

In order that the above objects, features and advantages of the present invention may be more clearly understood, a solution of the present invention will be further described below. It should be noted that the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the invention may be practiced otherwise than as described herein; it is to be understood that the embodiments described in this specification are only some embodiments of the invention, and not all embodiments.

Fig. 1 is a schematic diagram of a three-dimensional structure of an infrared detector mirror image pixel based on a CMOS process according to an embodiment of the present invention, and as shown in fig. 1, an infrared detector mirror image pixel 100 based on a CMOS process includes a CMOS measurement circuit system 101 and a CMOS infrared sensing structure, both the CMOS measurement circuit system 101 and the CMOS infrared sensing structure are manufactured by using a CMOS process, and the CMOS infrared sensing structure is directly manufactured on the CMOS measurement circuit system 101.

Specifically, the CMOS infrared sensing structure is used for converting an external infrared signal into an electrical signal and transmitting the electrical signal to the CMOS measurement circuit system 101, and the CMOS measurement circuit system 101 reflects temperature information of a corresponding infrared signal according to the received electrical signal, thereby realizing a temperature detection function of the infrared detector. The CMOS measuring circuit system 101 and the CMOS infrared sensing structure are both prepared by using a CMOS process, and the CMOS infrared sensing structure is directly prepared on the CMOS measuring circuit system 101, namely, the CMOS measuring circuit system 101 is prepared by adopting the CMOS process, and then the CMOS infrared sensing structure is continuously prepared by utilizing the CMOS process by utilizing the CMOS production line and parameters of various processes compatible with the production line.

Therefore, the CMOS process is utilized to realize the integrated preparation of the CMOS measuring circuit system 101 and the CMOS infrared sensing structure on the CMOS production line, compared with the MEMS process, the CMOS process has no process compatibility problem, the technical difficulty of the MEMS process is solved, the transportation cost can be reduced by adopting the CMOS production line process to prepare the infrared detector, and the risk caused by the transportation problem and the like is reduced; the infrared detector takes silicon oxide as a sacrificial layer, the silicon oxide is completely compatible with a CMOS (complementary metal oxide semiconductor) process, the preparation process is simple and easy to control, the CMOS process does not have the problem that the vacuum degree of a detector chip is influenced due to incomplete release of polyimide of the sacrificial layer, the subsequent film growth temperature is not limited by a sacrificial layer material, the multilayer process design of the sacrificial layer can be realized, the process is not limited by the process, the planarization can be easily realized by using the sacrificial layer, and the process difficulty and possible risks are reduced; the infrared detector prepared by the integrated CMOS process can realize the aims of high yield, low cost, high yield and large-scale integrated production of chips, and provides a wider application market for the infrared detector; the infrared detector based on the CMOS process can realize smaller size and thinner film thickness of a characteristic structure, so that the infrared detector has larger duty ratio, lower thermal conductivity and smaller thermal capacity, and the infrared detector has higher detection sensitivity, longer detection distance and better detection performance; the infrared detector based on the CMOS process can make the pixel size of the detector smaller, realize smaller chip area under the same array pixel, and is more beneficial to realizing the miniaturization of a chip; the infrared detector based on the CMOS process has the advantages of mature process production line, higher process control precision, better meeting design requirements, better product consistency, more contribution to circuit chip adjustment performance and more contribution to industrialized mass production.

As shown in fig. 1, the CMOS infrared sensing structure includes a reflective layer 110, an infrared conversion structure 120, and a plurality of first pillar structures 130 on a CMOS measurement circuitry 101, the first pillar structures 130 are located between the reflective layer 110 and the infrared conversion structure 120, the reflective layer 110 includes a reflective plate 112 and a supporting base 111, and the infrared conversion structure 120 is electrically connected to the CMOS measurement circuitry 101 through the first pillar structures 130 and the supporting base 111. The infrared conversion structure 120 includes an absorption plate 121 and a plurality of beam structures 122, the beam structures 122 are located on a side of the absorption plate 121 adjacent to the CMOS measurement circuitry 101, a second columnar structure 123 is disposed between the absorption plate 121 and the beam structures 122, and the absorption plate 121 is configured to convert an infrared signal into an electrical signal and is electrically connected to a corresponding first columnar structure 130 through the second columnar structure 123 and a corresponding beam structure 122.

Specifically, the first columnar structure 130 is located between the reflective layer 110 and the infrared conversion structure 120, and is configured to support the infrared conversion structure 120 after a sacrificial layer on the CMOS measurement circuit system 101 is released, the sacrificial layer is located between the reflective layer 110 and the infrared conversion structure 120, the first columnar structure 130 is a metal structure, an electrical signal converted by the absorption plate 121 via an infrared signal is transmitted to the CMOS measurement circuit system 101 through the corresponding second columnar structure 123, the corresponding beam structure 122, the corresponding first columnar structure 130, and the corresponding support base 111, the CMOS measurement circuit system 101 processes the electrical signal to reflect temperature information, and non-contact infrared temperature detection of the infrared detector is achieved. The CMOS infrared sensing structure outputs a positive electrical signal and a ground electrical signal through different electrode structures, and the positive electrical signal and the ground electrical signal are transmitted to the supporting base 111 electrically connected to the first columnar structure 130 through different first columnar structures 130, and fig. 1 schematically illustrates a direction parallel to the CMOS measurement circuit system 101, where the CMOS infrared sensing structure includes four first columnar structures 130, two of the first columnar structures 130 may be configured to transmit a positive electrical signal, the other two first columnar structures 130 are configured to transmit a ground electrical signal, and the CMOS infrared sensing structure may also include two first columnar structures 130 configured to transmit a positive electrical signal and a ground electrical signal, respectively. In addition, the reflective layer 110 includes a reflective plate 112 and a supporting base 111, a portion of the reflective layer 110 is used as a dielectric for electrically connecting the first columnar structure 130 with the CMOS measurement circuitry 101, i.e., the supporting base 111, the reflective plate 112 is used for reflecting infrared rays to the absorbing plate 121, and the secondary absorption of infrared rays is realized by matching with a resonant cavity formed between the reflective layer 110 and the absorbing plate 121, so as to improve the infrared absorption rate of the infrared detector and optimize the infrared detection performance of the infrared detector.

The CMOS infrared sensing structure further includes a patterned metal structure 140 disposed corresponding to the beam structure 122, and at least a portion of the reflective plate 112 is located in an orthographic projection area of the patterned metal structure 140.

Specifically, the patterned metal structure 140 is fixedly connected to the beam structure 122 and is insulated from the beam structure 122. The patterned metal structure 140 covers at least a portion of the reflective plate 112, and the infrared light passing through the absorption plate 121 is incident on the patterned metal structure 140 and then reflected to the absorption plate 121 by the patterned metal structure 140, and at this time, the reflective plate 112 cannot receive the infrared light, so that the height of the resonant cavity is changed, the condition that the resonant cavity generates resonance is destroyed, and the infrared light cannot generate resonance in the resonant cavity, that is, the resonant cavity cannot generate resonant light at this time.

The absorber plates 121 are electrically connected to the corresponding beam structures 122 through the second pillar structures 123, the beam structures 122 are electrically connected to the support base 111 through the corresponding first pillar structures 130, and the support base 111 is electrically connected to the CMOS measurement circuitry 101. The absorption plate 121 can absorb infrared radiation energy of the target object, convert the temperature signal into an effective electrical signal, and transmit the effective electrical signal to the corresponding beam structure 122 through the second columnar structure 123, and the beam structure 122 continues to transmit the effective electrical signal to the readout circuit through the corresponding first columnar structure 130 and the support base 111, while the beam structure 122 is also a heat conductive member for heat dissipation. The absorption plate 121 is also capable of absorbing energy of temperature noise radiation, converting the energy of temperature noise radiation into a noise signal, and transferring the noise signal to the readout circuit through the second columnar structure 123, the beam structure 122, the first columnar structure 130, and the support base 111 in this order. Since no resonant light is generated between the reflective layer 110 and the absorption plate 121, the absorption plate 121 can absorb little infrared radiation energy, and it can be considered that the absorption plate 121 does not respond to an infrared radiation signal, at this time, an electrical signal generated by the absorption plate 121 is a noise signal, and an electrical signal generated by the mirror image element is a noise signal, so that the noise signal of the infrared detector can be obtained through the mirror image element.

The infrared detector comprises an effective pixel and a mirror image pixel, wherein the effective pixel and the mirror image pixel are changed in resistance value due to heat radiation, when the mirror image pixel and the effective pixel are subjected to the same fixed radiation, the resistance values of the mirror image pixel and the effective pixel are the same, the temperature coefficients of the mirror image pixel and the effective pixel are also the same, the temperature drift amounts of the mirror image pixel and the effective pixel are the same under the same environment temperature, and the change of the mirror image pixel and the effective pixel is synchronous. Therefore, the difference between the image element and the effective element is that the image element does not respond to the infrared radiation signal, and the effective element responds to the infrared radiation signal, that is, the signal generated by the effective element is the superposition of the infrared radiation signal and the noise signal, and after the noise of the signal generated by the effective element is reduced, the infrared radiation signal of the target object can be obtained, so that the accuracy of the detection result is improved.

In summary, in the embodiment of the invention, the CMOS infrared sensing structure includes the patterned metal structure disposed corresponding to the beam structure, at least a part of the reflective plate is located in the orthographic projection region of the patterned metal structure, the infrared light transmitted through the absorption plate is reflected on the surface of the beam structure, and the reflective plate does not reflect the infrared light, that is, the height of the resonant cavity between the CMOS measurement circuit system and the absorption plate is changed, so that the resonant cavity no longer satisfies the resonance condition of the infrared light, and therefore no resonant light is generated in the resonant cavity, and at this time, the electrical signal generated by the absorption plate is derived from temperature noise, and therefore, the noise signal of the infrared detector can be obtained by the mirror image element, and accordingly, a more accurate detection signal can be obtained, thereby improving the accuracy of the detection result.

The CMOS manufacturing process of the CMOS infrared sensing structure comprises a metal interconnection process, a through hole process and an RDL process, wherein the CMOS infrared sensing structure comprises at least two metal interconnection layers, at least two dielectric layers and a plurality of interconnection through holes, the dielectric layers at least comprise a sacrificial layer and a heat sensitive dielectric layer, the heat sensitive dielectric layer at least comprises a heat sensitive layer and also can comprise a supporting layer and/or a passivation layer, and the metal interconnection layers at least comprise a reflecting layer 110 and an electrode layer; the thermal sensitive medium layer comprises a thermal sensitive material with a resistance temperature coefficient larger than a set value, the resistance temperature coefficient can be larger than or equal to 0.015/K, for example, the thermal sensitive material with the resistance temperature coefficient larger than the set value forms a thermal sensitive layer in the thermal sensitive medium layer, the thermal sensitive medium layer is used for converting temperature change corresponding to infrared radiation absorbed by the thermal sensitive medium layer into resistance change, and then infrared target signals are converted into signals capable of being read electrically through the CMOS measurement circuit system 101.

Specifically, the metal interconnection process is used for realizing the electrical connection of an upper metal interconnection layer and a lower metal interconnection layer, the through hole process is used for forming an interconnection through hole for connecting the upper metal interconnection layer and the lower metal interconnection layer, the RDL process is a redistribution layer process, specifically, a layer of metal is re-distributed above the top metal of the circuit and is electrically connected with the top metal of the circuit through a tungsten column, the reflection layer 110 in the infrared detector can be prepared on the top metal of the CMOS measurement circuit system 101 by adopting the RDL process, and the support base 111 on the reflection layer 110 is electrically connected with the top metal of the CMOS measurement circuit system 101. In addition, the heat-sensitive dielectric layer comprises a heat-sensitive material with a resistance temperature coefficient larger than a set value, and the resistance temperature coefficient can be larger than or equal to 0.015/K, so that the detection sensitivity of the infrared detector can be improved.

Furthermore, embodiments of the present invention provide that the patterned metal structure 140 is located on a side of the absorber plate 121 adjacent to the CMOS measurement circuitry 101, as shown in fig. 1. The patterned metal structure 140 is formed before the preparation of the effective pixel is completed, so that the effective pixel and the mirror image pixel can be simultaneously prepared by adding a process and matching with a corresponding mask, the patterned metal structure 140 is added in the mirror image pixel, the structure of the effective pixel is not changed, the synchronous preparation of the two pixel structures is realized, and the process flow of the infrared detector is simplified.

Illustratively, as shown in fig. 1, the second pillar structures 123 are electrically connected to the corresponding beam structures 122 and insulated from the patterned metal structures 140, and the beam structures 122 are in contact with the patterned metal structures 140 through the patterned dielectric structures 150, i.e., the patterned metal structures 140 are fixed to the corresponding regions of the beam structures 122 through the patterned dielectric structures 150. Thus, the patterned metal structure 140 does not affect the electrical performance of the absorbing plate 121, and the electrical performance of the mirror image element of the infrared sensor is not affected.

Beam structure 122 is located one side that absorption plate 121 closes on CMOS measurement circuitry 101, and beam structure 122 is located the different layers of absorption plate 121 promptly, and the area of beam structure 122 can not cause the influence to the area of absorption plate 121, is favorable to realizing absorption plate 121 of bigger area to can improve the radiation absorption of infrared detector image pixel, thereby can acquire more accurate noise signal, do benefit to improving infrared detector's detection performance. In addition, the size of the mirror image pixel structure of the infrared detector is no longer limited by the sum of the area of the absorption plate 121 and the area of the beam structure 122, so that the size of the mirror image pixel of the infrared detector can be reduced, and the development of miniaturization of the infrared detector is facilitated.

It should be noted that the patterned metal structure 140 may be located in the hollow area between the beam structures 122 as shown in fig. 1, or the patterned metal structure 140 may be located opposite to the beam structures 122 and in contact with the beam structures 122. These two cases will be described in detail below.

Fig. 2 is a schematic structural diagram of a CMOS measurement circuit system according to an embodiment of the present invention. With reference to fig. 1 and fig. 2, the cmos measurement circuit system 101 includes a bias voltage generation circuit 7, a column-level analog front-end circuit 8 and a row-level circuit 9, an input end of the bias voltage generation circuit 7 is connected to an output end of the row-level circuit 9, an input end of the column-level analog front-end circuit 8 is connected to an output end of the bias voltage generation circuit 7, the row-level circuit 9 includes a row-level mirror image element Rsm and a row selection switch K1, and the column-level analog front-end circuit 8 includes a blind image element RD; the row-level circuit 9 is distributed in each pixel, selects a signal to be processed according to a row strobe signal of the timing sequence generating circuit, and outputs a current signal to the column-level analog front-end circuit 8 under the action of the bias generating circuit 7 to perform current-voltage conversion output; the row-level circuit 9 outputs a third bias voltage VRsm to the bias generation circuit 7 when being controlled by the row selection switch K1 to be gated, the bias generation circuit 7 outputs a first bias voltage V1 and a second bias voltage V2 according to the input constant voltage and the third bias voltage VRsm, and the column-level analog front-end circuit 8 obtains two currents according to the first bias voltage V1 and the second bias voltage V2, performs transimpedance amplification on the difference between the two generated currents, and outputs the amplified currents as an output voltage.

Specifically, the row-level circuit 9 includes a row-level mirror image element Rsm and a row selection switch K1, and the row-level circuit 9 is configured to generate a third bias voltage VRsm according to a gating state of the row selection switch K1. Illustratively, the row-level image elements Rsm may be subjected to a shading process, so that the row-level image elements Rsm are subjected to a fixed radiation of a shading sheet having a temperature constantly equal to the substrate temperature, the row selection switch K1 may be implemented by a transistor, the row selection switch K1 is closed, and the row-level image elements Rsm are connected to the bias generation circuit 7, that is, the row-level circuit 9 outputs the third bias voltage VRsm to the bias generation circuit 7 when being controlled by the row selection switch K1 to be turned on. The bias generating circuit 7 may include a first bias generating circuit 71 and a second bias generating circuit 72, the first bias generating circuit 71 being configured to generate a first bias voltage V1 according to an input constant voltage, which may be, for example, a positive power supply signal with a constant voltage. The second bias generating circuit 72 may include a bias control sub-circuit 721 and a plurality of gate driving sub-circuits 722, the bias control sub-circuit 721 controlling the gate driving sub-circuits 722 to generate the corresponding second bias voltages V, respectively, according to the third bias voltage VRsm.

The column-level analog front-end circuit 8 includes a plurality of column control sub-circuits 81, the column control sub-circuits 81 are disposed in correspondence with the gate driving sub-circuits 722, and exemplarily, the column control sub-circuits 81 may be disposed in one-to-one correspondence with the gate driving sub-circuits 722, and the gate driving sub-circuits 722 are configured to provide the second bias voltage V2 to the corresponding column control sub-circuits 81 according to their own gate states. Illustratively, it may be set that when the gate driving sub-circuit 722 is gated, the gate driving sub-circuit 722 supplies the second bias voltage V2 to the corresponding column control sub-circuit 81; when the gate driving sub-circuit 722 is not gated, the gate driving sub-circuit 722 stops supplying the second bias voltage V2 to the corresponding column control sub-circuit 81.

The column-level analog front-end circuit 8 comprises an effective pixel RS and a blind pixel RD, the column control sub-circuit is used for generating a first current I1 according to a first bias voltage V1 and the blind pixel RD, generating a second current I2 according to a second bias voltage V2 and the effective pixel RS, performing transimpedance amplification on a difference value of the first current I1 and the second current I2 and outputting the difference value, and the row-level image pixel Rsm and the effective pixel RS have the same temperature drift amount under the same environment temperature.

Illustratively, the row-level image elements Rsm are thermally insulated from the CMOS measurement circuitry 101 and are shaded, and the row-level image elements Rsm are subjected to a fixed radiation from a shade having a temperature that is constantly equal to the substrate temperature. The absorption plate 121 of the effective pixel RS is thermally insulated from the CMOS measurement circuitry 101, and the effective pixel RS receives external radiation. The absorption plates 121 of the row-level mirror image elements Rsm and the effective elements RS are thermally insulated from the CMOS measurement circuitry 101, and thus the row-level mirror image elements Rsm and the effective elements RS have a self-heating effect.

When the corresponding row-level mirror image element Rsm is gated through the row selection switch K1, the resistance value of both the row-level mirror image element Rsm and the effective pixel RS is changed due to joule heat, but when the row-level mirror image element Rsm and the effective pixel RS are subjected to the same fixed radiation, the resistance value of the row-level mirror image element Rsm and the resistance value of the effective pixel RS are the same, the temperature coefficients of the row-level mirror image element Rsm and the temperature coefficient of the effective pixel RS are also the same, the temperature drift amounts of the row-level mirror image element Rsm and the effective pixel RS are the same at the same environmental temperature, the change of the row-level mirror image element Rsm and the effective pixel RS are synchronous, the characteristic that the temperature drift amounts of the row-level mirror image element Rsm and the effective pixel RS at the same environmental temperature are the same is utilized, and the resistance value change of the row-level mirror image element Rsm and the effective pixel RS due to the self-heating effect is effectively compensated, and the stable output of the reading circuit is achieved.

In addition, by arranging the second bias generating circuit 7 to include a bias control sub-circuit 721 and a plurality of gate driving sub-circuits 722, the bias control sub-circuit 721 is configured to control the gate driving sub-circuits 722 to generate corresponding second bias voltages V2 respectively according to the row control signal, so that each row of pixels has one path to drive the entire columns of pixels in the row separately, the requirement for the second bias voltages V2 is reduced, that is, the driving capability of the bias generating circuit 7 is improved, and the readout circuit is advantageously used to drive a larger-scale infrared detector pixel array. In addition, the specific detailed operation principle of the CMOS measurement circuit system 101 is well known to those skilled in the art, and will not be described herein.

Optionally, with continued reference to fig. 1, the patterned metal structure 140 is located in a hollow region between the beam structures 122.

Specifically, fig. 3 is a schematic diagram of a film structure of an infrared detector mirror image pixel based on a CMOS process, as shown in fig. 3, after beam structures 122 are formed, a hollow region exists between adjacent beam structures 122, no other structure is disposed in the hollow region, and a patterned metal structure 140 is disposed in the hollow region, so that the space inside the infrared detector mirror image pixel can be effectively utilized, the utilization rate of the space inside the infrared detector mirror image pixel is increased, an additional space does not need to be disposed for the patterned metal structure 140, and the miniaturization development of the infrared detector is facilitated.

As shown in fig. 3, the patterned metal structure 140 contacts the beam structure 122 through the patterned dielectric structure 150, and the patterned dielectric structure 150 covers the patterned metal structure 140, so as to support the patterned metal structure 140 and maintain the structural stability of the patterned metal structure 140. The patterned-media structure 150 is fabricated using an insulating material, and the patterned-media structure 150 can also function to insulate the patterned-metal structure 140 from the beam structure 122. In the embodiment of the invention, the patterned medium structure 150 has both supporting and insulating functions, so that an insulating layer and a supporting layer are not required to be separately arranged, the number of film layers in the mirror image pixel of the infrared detector can be reduced, and the number of process procedures is reduced, thereby saving the process time of the infrared detector and improving the production efficiency of the infrared detector.

Optionally, with continued reference to fig. 3, the patterned metal structure 140 is disposed in a same layer as the beam structure 122.

Illustratively, taking the infrared detector mirror image pixel shown in fig. 3 as an example, the method for manufacturing the infrared detector mirror image pixel 100 may include forming a reflective layer 110 on the CMOS measurement circuitry 101 by using a CMOS process, and etching the reflective layer 110 to form a supporting base 111 and a reflective plate 112. The first pillar structure 130 and the beam structure 122 are sequentially on the reflective layer 110. Insulating material is filled in the hollow area between the adjacent beam structures 122 and the patterned dielectric structure 150 is formed, that is, the patterned dielectric structure 150 and the beam structure 122 are arranged at the same layer, and the patterned metal structure 140 is formed by filling the patterned dielectric structure 150 with metal material, that is, the patterned metal structure 140 and the patterned dielectric structure 150 are arranged at the same layer, so that the beam structure 122 and the patterned metal structure 140 are arranged at the same layer. A second columnar structure 123 and an absorbing plate 121 are sequentially formed on the side of the beam structure 122 away from the CMOS measurement circuitry 101, wherein the second columnar structure 123 is electrically connected to the beam structure 122, thereby forming an infrared detector mirror image element as shown in fig. 3.

According to the embodiment of the invention, the patterned metal structure 140 and the beam structure 122 are arranged on the same layer, so that the total thickness of the film layer in the infrared detector mirror image pixel can be reduced, the size of the infrared detector mirror image pixel can be reduced, and the infrared detector can be favorably developed towards miniaturization.

Optionally, fig. 4 is a schematic diagram of a film structure of another infrared detector mirror image pixel based on a CMOS process according to an embodiment of the present invention, and as shown in fig. 4, the beam structure 122 includes a first electrode layer 211 and a passivation layer 220, where the first electrode layer 211 is located on a side of the passivation layer 220 adjacent to the CMOS measurement circuitry 101.

The patterned metal structure 140 is located on a side of the passivation layer 220 away from the first electrode layer 211 and is disposed in contact with the passivation layer 220, and the patterned metal structure 140 conforms to the pattern of the beam structure 122.

Illustratively, taking the infrared detector mirror image pixel shown in fig. 4 as an example, the method for manufacturing the infrared detector mirror image pixel 100 may include forming a reflective layer 110 on the CMOS measurement circuitry 101 by using a CMOS process, and etching the reflective layer 110 to form a supporting base 111 and a reflective plate 112. A first column structure 130, a first electrode layer 211 and a passivation layer 220 are sequentially formed on the reflective layer 110, wherein the first column structure 130 is in direct contact with the supporting base 111, and the first electrode layer 211 is in direct contact with the first column structure 130. A patterned metal structure 140 is formed on the passivation layer 220 in accordance with the beam structure 122 pattern. A second pillar structure 123 and an absorber plate 121 are formed in sequence on the side of the patterned metal structure 140 remote from the CMOS measurement circuitry 101, wherein the second pillar structure 123 contacts the first electrode layer 211 through the patterned metal structure 140 and the passivation layer 220, thereby forming an infrared detector mirror image element as shown in fig. 4.

In the embodiment of the invention, the patterned metal structure 140 is in contact with the passivation layer 220, and the passivation layer 220 can isolate the first electrode layer 211 from the patterned metal structure 140 while protecting the first electrode layer 211, so that the first electrode layer 211 is isolated from the patterned metal structure 140, and an additional insulating layer is not required to be arranged, thereby being beneficial to reducing the thickness of a CMOS infrared sensing structure and reducing the number of process procedures, so that the process time of the infrared detector can be saved, and the production efficiency of the infrared detector can be improved; the size of the mirror image pixel of the infrared detector can be reduced, and the development of the infrared detector towards miniaturization is facilitated.

Alternatively, with continued reference to fig. 3 and 4, the beam structure 122 includes a first electrode layer 211, the absorber plate 121 includes a second electrode layer 212 and a thermally sensitive layer 230, the second electrode layer 212 is electrically connected to the first electrode layer 211 through a second columnar structure 123, and the first electrode layer 211 is electrically connected to the first columnar structure 130.

Illustratively, as shown in fig. 3 and 4, the thermosensitive layer 230 is located on a side of the second electrode layer 212 away from the CMOS measurement circuitry 101, the thermosensitive layer 230 is used for converting a temperature signal into an electrical signal, and the second electrode layer 212 is used for adjusting the resistance of the thermosensitive layer 230. The first electrode layer 211 includes a positive electrode structure and a negative electrode structure, the positive thermosensitive signal generated by the thermosensitive layer 230 is transmitted to the positive electrode structure through the second columnar structure 123, the positive electrode structure transmits the positive thermosensitive signal generated by the thermosensitive layer 230 to the readout circuit through the corresponding first columnar structure 130, the negative thermosensitive signal generated by the thermosensitive layer 230 is transmitted to the negative electrode structure through the second columnar structure 123, and the negative electrode structure transmits the positive thermosensitive signal generated by the thermosensitive layer 230 to the readout circuit through the corresponding first columnar structure 130, so as to implement the detection function of the noise signal. A support layer for supporting the absorber plate 121 after releasing the sacrificial layer may be provided on the side of the heat sensitive layer 230 and the second electrode layer 212 adjacent to the beam structure 122, and a passivation layer for protecting the heat sensitive layer 230 and the second electrode layer 212 from oxidation or corrosion may be provided on the side of the heat sensitive layer 230 and the second electrode layer 212 remote from the beam structure 122.

For example, the material constituting the heat sensitive layer 230 may include at least one of amorphous silicon, amorphous germanium, amorphous silicon germanium, titanium oxide, vanadium oxide, or titanium vanadium oxide, the material constituting the support layer may include one or more of amorphous carbon, aluminum oxide, amorphous silicon, amorphous germanium, or amorphous silicon germanium, the material constituting the electrode layer may include one or more of titanium, titanium nitride, tantalum nitride, titanium tungsten alloy, nickel-chromium alloy, nickel-silicon alloy, nickel, or chromium, and the material constituting the passivation layer may include one or more of amorphous carbon, aluminum oxide, amorphous silicon, amorphous germanium, or amorphous silicon germanium. In addition, when the absorption plate 121 is disposed to include the thermal sensitive layer 230, and the thermal sensitive layer 230 is made of amorphous silicon, amorphous carbon, amorphous germanium, or amorphous silicon germanium, the supporting layer and/or the passivation layer on the beam structure 122 may be replaced by the thermal sensitive layer 230, because the thermal conductivity of the amorphous silicon, amorphous germanium, or amorphous silicon germanium is relatively low, which is beneficial to reducing the thermal conductivity of the beam structure 122, and further improving the infrared responsivity of the infrared detector.

It should be noted that fig. 3 and 4 are only exemplary to provide the second electrode layer 212 on the side of the thermal sensitive layer 230 adjacent to the CMOS measurement circuitry 101. In other embodiments, the second electrode layer 212 may be disposed on a side of the thermal sensitive layer 230 away from the CMOS measurement circuit system 101, and a dielectric layer is disposed between the second electrode layer 212 and the thermal sensitive layer 230. The dielectric layer and the thermal sensitive layer 230 are hollowed out to form a through hole penetrating through the dielectric layer and the thermal sensitive layer 230, and the second columnar structure 123 penetrates through the through hole to be electrically connected with the second electrode layer 212, as shown in fig. 5.

Optionally, a sacrificial layer (not shown in the figure) is disposed between the reflective layer 110 and the absorption plate 121, the sacrificial layer is used for forming a hollow structure of the CMOS infrared sensing structure, the material of the sacrificial layer is silicon oxide, and the sacrificial layer is etched by using at least one of gas-phase hydrogen fluoride, carbon tetrafluoride and trifluoromethane. The sacrificial layer may be made of silicon oxide, which is a commonly used material in CMOS processes, i.e., silicon oxide is compatible with CMOS processes, so that the sacrificial layer can be formed using CMOS processes. For example: a silicon oxide layer is deposited on one side of the reflective layer 110, and then a silicon oxide layer with a specific pattern is formed by etching, i.e., a sacrificial layer is formed. Therefore, the readout circuit and the sacrificial layer in the CMOS measurement circuit system 101 can be prepared by using a CMOS process, which is beneficial to realizing full CMOS process flow of the infrared detector, i.e., the integrated manufacturing of the infrared detector can be realized by using the CMOS process, which is beneficial to improving the manufacturing yield and productivity of the infrared detector and reducing the manufacturing cost of the infrared detector.

Optionally, fig. 6 is a schematic structural diagram of a beam structure according to an embodiment of the present invention, as shown in fig. 6, the beam structure 122 is respectively connected to the intermediate support structure 160 and the first pillar structure 130, two parallel beam structures 122 meeting at the same node in a beam path from the intermediate support structure 160 to the corresponding first pillar structure 130 in the plurality of beam structures 122 are respectively a first half-bridge structure 1221 and a second half-bridge structure 1222, and the first half-bridge structure 1221 and the second half-bridge structure 1222 form a thermally symmetric structure; wherein the length of the first half-bridge structure 1221 is greater than the length of the second half-bridge structure 1222, and the thickness of the first half-bridge structure 1221 is greater than the thickness of the second half-bridge structure 1222 in a direction perpendicular to the CMOS measurement circuitry 101.

Specifically, when the absorption plate 121 and the beam structure 122 are located on different layers, the absorption plate 121 is located on the side of the beam structure 122 adjacent to the CMOS measurement circuitry 101, and an intermediate support structure 160 is disposed on the same layer as the beam structure 122 for supporting the beam structure 122 and maintaining the stability of the beam structure 122. Intermediate support structure 160 is fabricated using the same process flow as beam structure 122, i.e., intermediate support structure 160 includes a first electrode layer and a passivation layer.

Illustratively, as shown in fig. 6, parallel beam structure a and parallel beam structure B meet at the same node a, parallel beam structure C and parallel beam structure D meet at node B and node C, and parallel beam structure e and parallel beam structure f meet at the same node D. In addition, the length of the first half-bridge structure 1221 in the thermally symmetric structure is greater than that of the second half-bridge structure 1222, so that the parallel beam structure a is the first half-bridge structure 1221, the parallel beam structure b is the second half-bridge structure 1222 and constitutes a thermally symmetric structure, the parallel beam structure c is the first half-bridge structure 1221, the parallel beam structure d is the second half-bridge structure 1222 and constitutes a thermally symmetric structure, the parallel beam structure e is the first half-bridge structure 1221, and the parallel beam structure f is the second half-bridge structure 1222 and constitutes a thermally symmetric structure.

The thickness of the first half-bridge structure 1221 is greater than the thickness of the second half-bridge structure 1222, and in the case that the first half-bridge structure 1221 and the second half-bridge structure 1222 are equal in length, the first half-bridge structure 1221 has a greater thickness, and therefore conducts heat faster than the second half-bridge structure 1222. The length of the first half-bridge structure 1221 and the length of the second half-bridge structure 1222 are asymmetrically designed in the present disclosure, that is, the length of the first half-bridge structure 1221 is set to be greater than the length of the second half-bridge structure 1221, so as to slow down the heat conduction speed of the first half-bridge structure 1221 with a fast heat conduction speed caused by a thickness factor, and further achieve that the unbalanced difference between the heat conductivities of the first half-bridge structure 1221 and the second half-bridge structure 1222 in the thermal symmetric structure is less than or equal to a predetermined value, which may be, for example, 20%, that is, the difference between the heat conduction speeds of the first half-bridge structure 1221 and the second half-bridge structure 1222 in the thermal symmetric structure is less than or equal to 20%, and for example, the heat conduction speed of the first half-bridge structure 1221 is 1, the heat conduction speed of the second half-bridge structure 1222 is greater than or equal to 0.8, and less than or equal to 1.2.

Referring to fig. 1 and 6, the thermal conductivities of the parallel beam structure a and the parallel beam structure b are similar, the thermal conductivities of the parallel beam structure c and the parallel beam structure d are similar, the thermal conductivities of the parallel beam structure e and the parallel beam structure f are similar, the heat of the absorption plate 121 is transmitted to the parallel beam structure c and the parallel beam structure d substantially synchronously after passing through the parallel beam structure a and the parallel beam structure b, the heat is transmitted to the parallel beam structure e and the parallel beam structure f substantially synchronously after passing through the parallel beam structure e and the parallel beam structure f, the heat is transmitted to the first column structure 130 above and the first column structure 130 below substantially synchronously after passing through the parallel beam structure e and the parallel beam structure f, and the heat is dissipated by the CMOS measurement circuit system 101.

Thus, the time for the heat from the absorption plate 121 to reach the lower first columnar structure 130 through the first half-bridge structure 1221 and reach the upper first columnar structure 130 through the second half-bridge structure 1222 is similar, thereby realizing the thermal balance on the beam structure 122, reducing the total thermal conductance of the image element 100 of the infrared detector, optimizing the total thermal conductance of the infrared detector, such as the infrared detection performance of the infrared focal plane detector, and improving the Noise Equivalent Temperature Difference (NETD) performance of the infrared detector by more than 15%.

In addition, this disclosed embodiment sets up the great length of first half-bridge structure 1221 of thickness, be greater than the less length of second half-bridge structure 1221 of thickness, compare in the identical symmetrical structure of the length of first half-bridge structure 1221 and second half-bridge structure 1222, reduced the stress and the deformation that infrared detector mirror image pixel 100 received under the effect of the same power, under the same effort, the stress that infrared detector mirror image pixel 100 received reduces at least 10%, deformation reduces at least 50%, the stability and the shock resistance of infrared detector mirror image pixel 100 have been improved, and then whole infrared detector's structural stability has been improved, infrared detector's mechanical strength has been strengthened.

It should be noted that fig. 6 only exemplarily illustrates that the infrared detector mirror image pixel 100 includes three thermally symmetric structures formed by three first half-bridge structures 1221 and three second half-bridge structures 1222, and the specific number of thermally symmetric structures included in the infrared detector mirror image pixel 100 is not limited in the embodiment of the present disclosure, so that it is sufficient to ensure that the infrared detector mirror image pixel 100 includes at least one thermally symmetric structure.

Alternatively, fig. 7 is a schematic structural diagram of another infrared detector mirror image element based on a CMOS process according to an embodiment of the present invention, the infrared conversion structure 120 may include two beam structures 122 as shown in fig. 1, and the infrared conversion structure may further include four beam structures 122 as shown in fig. 7, that is, the infrared conversion structure includes a first beam structure 122a and a second beam structure 122b arranged along a first direction XX ', and a third beam structure 122c and a fourth beam structure 122d arranged along a second direction YY', where the first direction XX 'is perpendicular to the second direction YY'.

As shown in fig. 7, the first beam structure 122a and the second beam structure 122b include a thermal symmetric structure, the position of the thermal symmetric structure can refer to fig. 1, the third beam structure 122c and the fourth beam structure 122d do not include a thermal symmetric structure, the first beam structure 122a and the second beam structure 122b satisfy a thermal symmetric relationship, and the third beam structure 122c and the fourth beam structure 122d satisfy a thermal symmetric relationship.

As shown in fig. 7, the thermal conductance of the third beam structure 122c is set to be less than or equal to the thermal conductance of the first beam structure 122a or the thermal conductance of the second beam structure 122b, and the thermal conductance of the fourth beam structure 122d is set to be less than or equal to the thermal conductance of the first beam structure 122a or the thermal conductance of the second beam structure 122b, which is beneficial to reducing the total thermal conductance of the image pixel of the infrared detector and optimizing the infrared detection performance of the infrared detector formed by the image pixel of the infrared detector.

Alternatively, the infrared detector mirror image element 100 may be provided with one or two sets of two first columnar structures 130 arranged diagonally, as shown in fig. 1, the infrared detector mirror image element 100 is exemplarily provided with two sets of two first columnar structures 130 arranged diagonally, that is, the infrared detector mirror image element 100 is provided with the first columnar structures 130, or the infrared detector mirror image element 100 is provided with one set of two first columnar structures 130 arranged diagonally, that is, the infrared detector mirror image element 100 is provided with the two first columnar structures 130, as shown in fig. 8.

Alternatively, the first pillar structure 130 in the infrared detector mirror image pixel 100 may be a hollow pillar structure as shown in fig. 1, and the first pillar structure 130 may also be a solid pillar structure as shown in fig. 8.

For example, as shown in fig. 1, the first pillar structure 130 may be a hollow pillar structure, and the hollow pillar structure has low thermal conductivity, which can reduce the thermal conductivity of the whole structure. The first columnar structure 130 may also be a solid columnar structure, as shown in fig. 8, no residual sacrificial layer is left in the first columnar structure 130, so that the vacuum degree of the infrared detector mirror image pixel 100 can be improved, and the influence on the electrical performance of the infrared detector mirror image pixel 100 is avoided. Meanwhile, the mechanical strength of the solid column structure is high, and the structural stability of the mirror image pixel 100 of the infrared detector can be improved. Illustratively, the material of the solid pillar structure may be at least one of aluminum, copper, and tungsten.

Optionally, with continued reference to fig. 8, the reflector plate 112 is in electrical contact with a grounded support pedestal 111.

Specifically, as shown in fig. 8, the grounded support base 111 serves as a support and can discharge electric charges to the ground. The reflective plate 112 is electrically connected to the support base 111, which is grounded, and the charges accumulated in the reflective plate 112 can be discharged to the ground through the support base, so that the charges are prevented from accumulating to influence the electrical performance of the circuit.

Optionally, fig. 9 is a schematic diagram of a film structure of another infrared detector mirror image pixel based on a CMOS process according to an embodiment of the present invention, as shown in fig. 9, the CMOS infrared sensing structure further includes at least one sealing release insulating layer 170 located on the reflection layer 110, the sealing release insulating layer 170 is used for protecting the CMOS measurement circuit system 101 from a process during an etching process for manufacturing the CMOS infrared sensing structure, and the sealing release insulating layer 170 covers the first pillar structure 130.

Illustratively, as shown in fig. 9, the CMOS infrared sensing structure includes a hermetic release barrier layer 170, and the hermetic release barrier layer 170 is disposed on the reflective layer 110 and covers the first pillar structure 130. The supporting base 111 is used as a structure for electrically connecting the reading circuit and the CMOS infrared sensing structure, the closed release isolation layer 170 covers the dielectric layer below the closed release isolation layer 170 and the supporting base 111, and the effect of protecting the lower dielectric layer and the CMOS measuring circuit system is achieved. Meanwhile, the first columnar structure 130 is coated by the closed release insulating layer 170, and the closed release insulating layer can be used as a supporting structure of the first columnar structure 130, so that the mechanical strength of the first columnar structure 130 is enhanced, the structural stability of the mirror image pixel 100 is improved, and the structural stability and the impact resistance of the infrared detector can be improved.

Meanwhile, for the full CMOS process of the infrared detector, the closed release isolation layer 170 is located in the mirror image pixel and the effective pixel, for the effective pixel, the closed release isolation layer 170 is located in the resonant cavity of the closed release isolation layer, and the refractive index of the closed release isolation layer 170 is greater than that of vacuum, so that the optical path of the resonant cavity can be increased through the closed release isolation layer 170, the actual height of the resonant cavity can be reduced, the thickness of the sacrificial layer is reduced, and the release difficulty of the sacrificial layer is reduced.

Fig. 10 is a schematic diagram of a film structure of a mirror image pixel of an infrared detector based on a CMOS process according to another embodiment of the present invention, where a hermetic release isolation layer 170 may also be located at an interface between the CMOS measurement circuitry 101 and the CMOS infrared sensing structure, for example, the hermetic release isolation layer 170 is located between the reflective layer 110 and the CMOS measurement circuitry 101, that is, the hermetic release isolation layer 170 is located below a metal interconnection layer of the reflective layer 110, and the supporting base 111 is electrically connected to the CMOS measurement circuitry 101 through a through hole penetrating through the hermetic release isolation layer 170. Specifically, because the CMOS measurement circuit system 101 and the CMOS infrared sensing structure are both formed by using a CMOS process, after the CMOS measurement circuit system 101 is formed, a wafer including the CMOS measurement circuit system 101 is transferred to a next process to form the CMOS infrared sensing structure, and since silicon oxide is a most commonly used dielectric material in the CMOS process, and silicon oxide is mostly used as an insulating layer between metal layers on the CMOS circuit, if no insulating layer is used as a barrier when silicon oxide with a thickness of about 2um is corroded, the circuit will be seriously affected, so that a silicon oxide medium on the CMOS measurement circuit system is not corroded when the silicon oxide of the sacrificial layer is released, and the hermetic release insulating layer 170 is provided. After the CMOS measurement circuit system 101 is prepared and formed, a closed release isolation layer 170 is prepared and formed on the CMOS measurement circuit system 101, the CMOS measurement circuit system 101 is protected by the closed release isolation layer 170, and in order to ensure the electrical connection between the support base 111 and the CMOS measurement circuit system 101, after the closed release isolation layer 170 is prepared and formed, a through hole is formed in a region of the closed release isolation layer 170 corresponding to the support base 111 by using an etching process, and the support base 111 is electrically connected with the CMOS measurement circuit system 101 through the through hole. In addition, the hermetic release isolation layer 170 and the support base 111 are arranged to form a hermetic structure, so as to completely separate the CMOS measurement circuit system 101 from the sacrificial layer, thereby protecting the CMOS measurement circuit system 101.

Fig. 11 is a schematic diagram of a film structure of another infrared detector mirror image pixel based on a CMOS process according to an embodiment of the present invention, an interface between the CMOS measurement circuit system 101 and the CMOS infrared sensing structure is provided with at least one hermetic release isolation layer 170, that is, at least one hermetic release isolation layer 170 is provided between the reflection layer 110 and the CMOS measurement circuit system 101, and at least one hermetic release isolation layer 170 is provided on the reflection layer 110, which has the same effects as above and is not described herein again.

Fig. 9 illustrates only that the CMOS infrared sensing structure includes one hermetic release isolation layer 170, in other embodiments, the CMOS infrared sensing structure may further include two hermetic release isolation layers 170 as shown in fig. 12, or more hermetic release isolation layers 170, and the number of the dielectric layers is set according to specific requirements in practical applications, which is not limited in this embodiment of the present invention.

Fig. 13 is a schematic diagram of a film structure of another infrared detector mirror image pixel based on a CMOS process according to an embodiment of the present invention, as shown in fig. 13, based on the above embodiment, a CMOS manufacturing process of the CMOS measurement circuit system 101 may also include a metal interconnection process and a via process, the CMOS measurement circuit system 101 includes metal interconnection layers 1011, dielectric layers 1012 and a silicon substrate 1013 at the bottom that are arranged at intervals, and the upper and lower metal interconnection layers 1011 are electrically connected through the via 1014.

Referring to fig. 1 to 13, the CMOS infrared sensing structure 102 includes a resonant cavity formed by a reflective layer 110 and a heat sensitive medium layer, a suspended micro-bridge structure for controlling heat transfer, and a first pillar structure 130 having electrical connection and support functions, and the CMOS measurement circuitry 101 is used for measuring and processing an array resistance value formed by one or more CMOS infrared sensing structures 102 and converting an infrared signal into an electrical image signal.

Specifically, the resonant cavity may be formed by a cavity between the reflective layer 110 and the absorbing plate 121, for example, infrared light is reflected back and forth in the resonant cavity through the absorbing plate 121, so as to improve the detection sensitivity of the infrared detector, and due to the arrangement of the first columnar structure 130, the beam structure 122 and the absorbing plate 121 form a suspended micro-bridge structure for controlling heat transfer, and the first columnar structure 130 is electrically connected to the supporting base 111 and the corresponding beam structure 122, and is used for supporting the infrared conversion structure 120 on the first columnar structure 130.

Alternatively, the CMOS infrared sensing structure 102 may be fabricated on top of or in the same layer as the metal interconnect layers of the CMOS measurement circuitry 101.

Specifically, the metal interconnection layer of the CMOS measurement circuitry 101 may be a top metal layer in the CMOS measurement circuitry 101, the CMOS infrared sensing structure 102 may be fabricated on top of the metal interconnection layer of the CMOS measurement circuitry 101, and the CMOS infrared sensing structure 102 is electrically connected to the CMOS measurement circuitry 101 through the supporting base 111 on top of the metal interconnection layer of the CMOS measurement circuitry 101, so as to transmit the electrical signal converted by the infrared signal to the CMOS measurement circuitry 101, as shown in fig. 13.

Fig. 14 is a schematic diagram of a film structure of a mirror image pixel of an infrared detector based on a CMOS process according to another embodiment of the present invention. As shown in fig. 14, the CMOS infrared sensing structure 102 may also be prepared on the same layer as the metal interconnection layer of the CMOS measurement circuitry 101, that is, the CMOS measurement circuitry 101 and the CMOS infrared sensing structure 102 are arranged on the same layer, the CMOS infrared sensing structure 102 is arranged on one side of the CMOS measurement circuitry 101, and the top of the CMOS measurement circuitry 101 may also be provided with a hermetic release isolation layer to protect the CMOS measurement circuitry 101.

Optionally, the material constituting hermetic release barrier layer 170 includes at least one of silicon, germanium, silicon germanium, amorphous carbon, silicon carbide, aluminum oxide, silicon carbonitride, or silicon nitride.

Specifically, silicon, germanium, silicon germanium, amorphous carbon, silicon carbide, aluminum oxide, or silicon nitride are all CMOS process corrosion resistant materials, i.e., these materials are not corroded by the sacrificial layer release agent, so the hermetic release barrier layer 170 can be used to protect the CMOS measurement circuitry 101 from corrosion when the corrosion process is performed to release the sacrificial layer. In addition, the closed release isolation layer 170 covers the CMOS measurement circuit system 101, and the closed release isolation layer 170 may also be used to protect the CMOS measurement circuit system 101 from process influence during an etching process for manufacturing a CMOS infrared sensing structure.

Optionally, with continued reference to fig. 9 and 12, the CMOS infrared sensing structure further comprises: a planarization layer 180, the planarization layer 180 comprising a patterned media structure, the patterned media structure being located on the same layer as the support pedestal 111, and a Chemical Mechanical Polishing (CMP) process is used to make the surface of the planarization layer 180 facing away from the CMOS measurement circuitry 101 flush with the surface of the reflective layer 110 facing away from the CMOS measurement circuitry 101.

Specifically, a reflective layer 110 is formed on the CMOS measurement circuitry 101, and then the reflective layer 110 is patterned by etching, i.e., a supporting base 111 and a reflective plate 112 are formed. A space is present between the supporting base 111 and the reflective plate 112, and the surface of the reflective layer 110 is recessed. A flat layer 180 is deposited on the reflective layer 110, and the flat layer 180 can fill the recess of the reflective layer 110, at this time, the surface of the flat layer 180 on the side away from the CMOS measurement circuitry 101 is uneven, wherein the surface of the film layer corresponding to the supporting base 111 and the reflective plate 112 is higher. The CMP process is adopted to polish the surface of one side, away from the CMOS measurement circuit system 101, of the flat layer 180, the height of the film surface of the flat layer 180 corresponding to the supporting base 111 and the reflecting plate 112 is reduced, so that the surface, away from the CMOS measurement circuit system 101, of the flat layer 180 is flush with the surface, away from the CMOS measurement circuit system 101, of the reflecting layer 110, and each film layer formed in the subsequent process is guaranteed to be flat, so that the process difficulty can be reduced, the control precision of process parameters is high, and the yield of the infrared detector is improved.

Optionally, the image element of the infrared detector mirror image can be set based on a 3nm, 7nm, 10nm, 14nm, 22nm, 28nm, 32nm, 45nm, 65nm, 90nm, 130nm, 150nm, 180nm, 250nm or 350nm CMOS process, and the aforementioned dimensions represent process nodes of the integrated circuit, that is, feature dimensions in the integrated circuit processing process.

Optionally, the side length of the supporting base 111 is equal to or less than 3 micrometers and equal to or more than 0.5 micrometers.

Specifically, the material constituting the infrared detector mirror image pixel reflection layer 110 based on the CMOS process may be set to include at least one of aluminum, copper, tungsten, titanium, nickel, chromium, platinum, silver, ruthenium, or cobalt. In addition, the CMOS measurement circuit system 101 and the CMOS infrared sensing structure are both prepared by using a CMOS process, and the CMOS infrared sensing structure is directly prepared on the CMOS measurement circuit system 101, so that the side length of the support base 111 is less than or equal to 3 micrometers and greater than or equal to 0.5 micrometers, the width of the beam structure 122, that is, the width of a single line in the beam structure 122 is less than or equal to 0.3um, the height of the resonant cavity is greater than or equal to 1.5um and less than or equal to 2.5um, and the side length of a single pixel is greater than or equal to 6um and less than or equal to 17um. For the full CMOS process of the detector, the reflective layer 110 can be formed in both the effective pixel and the mirror image pixel by the same process, and for the effective pixel, the smaller the side length of the supporting base 111, i.e., the smaller the area of the supporting base 111, the larger the area of the reflective plate 112, the more infrared radiation energy absorbed by the sensor, and thus the detection efficiency of the infrared detector can be improved.

The embodiment of the invention also provides an infrared detector based on the CMOS process, and fig. 15 is a schematic three-dimensional structure diagram of the infrared detector based on the CMOS process provided by the embodiment of the invention. As shown in fig. 15, an infrared detector 200 based on a CMOS process includes any one of the above-mentioned embodiments of the infrared detector mirror image pixel 100 based on a CMOS process, and the advantageous effects of the above-mentioned embodiments are not described herein again. Illustratively, the infrared detector may be, for example, an uncooled infrared focal plane detector.

Optionally, as shown in fig. 4 and fig. 15, the beam structure 122 includes a first electrode layer 211 and a passivation layer 220, the first electrode layer 211 is located on a side of the passivation layer 220 adjacent to the CMOS measurement circuitry 101, the patterned metal structure 140 is located on a side of the passivation layer 220 away from the first electrode layer 211 and is disposed in contact with the passivation layer 220, and the patterned metal structure 140 conforms to the pattern of the beam structure 122.

The infrared detector 200 further includes an infrared detector effective pixel, and the length of the beam structure of the infrared detector mirror image pixel is greater than the length of the beam structure of the infrared detector effective pixel.

In particular, the beam structure 122 is also a thermally conductive member for dissipating heat. The beam structure 122 is in direct contact with the patterned metal structure 140 as shown in fig. 4, which is equivalent to increasing the thickness of the beam structure 122 in the infrared detector mirror image element, and is not beneficial to heat dissipation of the infrared detector mirror image element. Through the length that will prolong infrared detector mirror image pixel centre sill structure, can increase the length of the heat dissipation route of infrared detector mirror image pixel, do benefit to the heat dissipation that promotes infrared detector mirror image pixel to promote infrared detector's heat dispersion.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising one of 8230; \8230;" 8230; "does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present disclosure, which enable those skilled in the art to understand or practice the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An infrared detector mirror image pixel based on CMOS technology, comprising:

the CMOS manufacturing process of the CMOS infrared sensing structure comprises a metal interconnection process, a through hole process and an RDL (remote description language) process, wherein the CMOS infrared sensing structure comprises at least two metal interconnection layers, at least two dielectric layers and a plurality of interconnection through holes;

the CMOS infrared sensing structure further comprises a patterned metal structure arranged corresponding to the beam structure, at least part of the reflecting plate is located in an orthographic projection area of the patterned metal structure, and the patterned metal structure is used for reflecting infrared light to the absorbing plate;

the CMOS infrared sensing structure further comprises at least one layer of closed release isolation layer located on the reflecting layer, and the closed release isolation layer covers the first columnar structure.

2. The CMOS process-based infrared detector mirror pixel of claim 1, wherein the patterned metal structure is located in a hollow region between the beam structures.

3. The CMOS process-based infrared detector mirror pixel of claim 2, wherein the patterned metal structure is disposed in a same layer as the beam structure.

4. The CMOS process-based infrared detector mirror image pixel of claim 1, wherein the beam structure comprises a first electrode layer and a passivation layer, the first electrode layer is located on a side of the passivation layer adjacent to the CMOS measurement circuitry;

the patterned metal structure is located on one side, far away from the first electrode layer, of the passivation layer and is in contact with the passivation layer, and the patterned metal structure is consistent with the beam structure in pattern.

5. The CMOS process-based infrared detector mirror image pixel of claim 1, wherein the beam structure comprises a first electrode layer, the absorber plate comprises a second electrode layer and a thermally sensitive layer, the second electrode layer is electrically connected to the first electrode layer through the second pillar structure, and the first electrode layer is electrically connected to the first pillar structure.

6. The CMOS process-based infrared detector mirror image pixel according to claim 1, wherein a sacrificial layer is used for forming the CMOS infrared sensing structure into a hollowed-out structure, the sacrificial layer is made of silicon oxide, and the sacrificial layer is etched by at least one of gas-phase hydrogen fluoride, carbon tetrafluoride and trifluoromethane.

7. The CMOS process-based infrared detector mirror image pixel of claim 5, wherein the beam structures are respectively connected to an intermediate support structure and the first columnar structure, two parallel beam structures meeting at the same node in a beam path from the intermediate support structure to the corresponding first columnar structure in the plurality of beam structures are respectively a first half-bridge structure and a second half-bridge structure, and the first half-bridge structure and the second half-bridge structure form a thermally symmetric structure; wherein the length of the first half-bridge structure is greater than the length of the second half-bridge structure, and the thickness of the first half-bridge structure is greater than the thickness of the second half-bridge structure in a direction perpendicular to the CMOS measurement circuitry.

8. The CMOS process-based infrared detector mirror image pixel of claim 1, wherein said hermetic release barrier is used to protect said CMOS measurement circuitry from process effects during etching process for fabricating said CMOS infrared sensing structure.

9. The CMOS process-based infrared detector mirror image pixel of claim 1, wherein the material comprising the hermetic release barrier comprises at least one of silicon, germanium, silicon germanium, amorphous carbon, silicon carbide, aluminum oxide, or silicon nitride.

10. An infrared detector based on a CMOS process, characterized by comprising the infrared detector mirror image element based on a CMOS process according to any one of claims 1 to 9.

11. The CMOS process-based infrared detector according to claim 10, wherein the beam structure comprises a first electrode layer and a passivation layer, the first electrode layer is located on a side of the passivation layer adjacent to the CMOS measurement circuitry, the patterned metal structure is located on a side of the passivation layer away from the first electrode layer and is disposed in contact with the passivation layer, and the patterned metal structure conforms to a pattern of the beam structure;