阅读说明：本技术 红外探测器及其制备方法 (Infrared detector and preparation method thereof ) 是由 康晓旭 蒋宾 于 2021-09-08 设计创作，主要内容包括：本申请提供一种红外探测器及其制备方法,涉及红外探测器技术领域,该红外探测器包括基底、牺牲层以及微桥结构；牺牲层设置在基底上,牺牲层内设置有连接孔；微桥结构的部分设置在所述连接孔内,且位于该连接孔内的所述微桥结构与设置在所述基底内的电路电连接。本申请通过对微桥结构进行改进,使得微桥结构包括层叠设置的第一导电层和第二导电层,与相关技术中,微桥结构仅包括一层导电层的技术方案相比,增加了微桥结构的厚度,进而降低了微桥结构的电阻,提高了红外探测器的性能。(The application provides an infrared detector and a preparation method thereof, relating to the technical field of infrared detectors, wherein the infrared detector comprises a substrate, a sacrificial layer and a microbridge structure; the sacrificial layer is arranged on the substrate, and a connecting hole is formed in the sacrificial layer; part of the micro-bridge structure is arranged in the connecting hole, and the micro-bridge structure in the connecting hole is electrically connected with the circuit arranged in the substrate. This application is through improving the microbridge structure for the microbridge structure is including range upon range of first conducting layer and the second conducting layer that sets up, and in the correlation technique, the microbridge structure only includes the technical scheme of one deck conducting layer and compares, has increased the thickness of microbridge structure, and then has reduced the resistance of microbridge structure, has improved infrared detector's performance.)

1. An infrared detector is characterized by comprising a substrate, a sacrificial layer and a microbridge structure;

the sacrificial layer is arranged on the substrate, and a connecting hole is formed in the sacrificial layer;

the micro-bridge structure is partially arranged in the connecting hole, and the micro-bridge structure positioned in the connecting hole is electrically connected with a circuit arranged in the substrate, wherein the micro-bridge structure comprises a first conducting layer and a second conducting layer which are arranged in a stacked mode, and the first conducting layer is connected with the inner wall of the connecting hole.

2. The infrared detector of claim 1, wherein said first conductive layer comprises a first support layer and a first bridge deck connected to said first support layer, said first bridge deck overlying a portion of said sacrificial layer;

the first supporting layer is arranged in the connecting hole, and the top surface of the end part of the first bridge deck, which deviates from the first bridge deck, is lower than the top surface of the sacrificial layer.

3. The infrared detector of claim 2, wherein said second conductive layer comprises a second support layer and a second bridge deck connected to said second support layer, said second bridge deck being disposed on said first bridge deck;

the second supporting layer is arranged in the connecting hole, and the top surface of the end part of the second bridge deck deviated from the second supporting layer is flush with the top surface of the end part of the first bridge deck deviated from the first supporting layer.

4. The infrared detector of claim 3, characterized in that the projected area of said second bridge deck on said substrate is smaller than the projected area of said first bridge deck on said substrate.

5. The infrared detector as claimed in claim 4, further comprising a dielectric layer filled in the region surrounded by the second conductive layer, wherein a top surface of the dielectric layer is flush with a top surface of the second bridge deck.

6. The infrared detector as set forth in claim 2, wherein said second conductive layer is disposed in said connecting hole and has a longitudinal section in a cross section perpendicular to said substrate, said longitudinal section of said second conductive layer being U-shaped, a top surface of an end portion of said second conductive layer being lower than a top surface of said sacrifice layer.

7. The infrared detector as set forth in claim 1, wherein the first conductive layer is disposed in the connecting hole, and a top surface of an end portion of the first conductive layer is lower than a top surface of the sacrificial layer;

the second conducting layer covers the first conducting layer, one end of the second conducting layer extends out of the connecting hole and covers part of the sacrificial layer.

8. The infrared detector as claimed in claim 7, wherein said first conductive layer includes two sub-conductive layers stacked in sequence, and the two sub-conductive layers are made of different materials.

9. The infrared detector as claimed in any one of claims 1 to 8, further comprising a protective layer covering the sacrificial layer and the top surface of the microbridge structure;

or the protective layer covers the sacrificial layer, the micro-bridge structure and the top surface of part of the dielectric layer.

10. A preparation method of an infrared detector is characterized by comprising the following steps:

providing a substrate;

forming a sacrificial layer on the substrate, wherein the sacrificial layer is internally provided with a connecting hole, and the connecting hole exposes part of the substrate;

and forming a micro-bridge structure, wherein part of the micro-bridge structure is arranged in the connecting hole, the micro-bridge structure comprises a first conducting layer and a second conducting layer which are arranged in a stacked mode, and the first conducting layer is connected with the inner wall of the connecting hole.

11. The method of claim 10, wherein the step of forming a sacrificial layer on the substrate comprises:

forming a mask layer on the sacrificial layer;

patterning the mask layer to form a plurality of mask openings arranged at intervals in the mask layer;

removing the sacrificial layer exposed in each mask opening to form a plurality of connecting holes arranged at intervals in the sacrificial layer;

the step of forming the microbridge structure includes:

forming a plurality of microbridge structures, a portion of each of the microbridge structures being disposed within one of the connecting apertures.

12. The method of claim 11, wherein the step of forming a plurality of microbridge structures comprises:

forming a first initial conducting layer and a second initial conducting layer which are sequentially stacked in the connecting hole, wherein the first initial conducting layer and the second initial conducting layer extend out of the connecting hole and cover the sacrificial layer;

and removing part of the first initial conducting layer and part of the second initial conducting layer, wherein the remained first initial conducting layer forms a first conducting layer, the remained second initial conducting layer forms a second conducting layer, and at least one of the first conducting layer and the second conducting layer extends out of the connecting hole and covers part of the sacrificial layer.

13. The method for manufacturing an infrared detector according to claim 12, wherein after the step of forming a first initial conductive layer and a second initial conductive layer which are sequentially stacked in the connection hole, and before the step of removing a part of the first initial conductive layer and a part of the second initial conductive layer, the method further comprises:

forming a dielectric layer in a region surrounded by the second initial conducting layer, wherein the top surface of the dielectric layer is flush with the top surface of the second initial conducting layer;

and forming a first photoresist layer on the second initial conducting layer and the dielectric layers, wherein the first photoresist layer is internally provided with a first opening, and the first opening exposes the area between the adjacent dielectric layers and a part of the area of each dielectric layer.

14. The method of claim 13, wherein the step of removing a portion of the first initial conductive layer and a portion of the second initial conductive layer comprises:

removing a part of the first initial conductive layer and a part of the second initial conductive layer exposed in the first opening so as to form a filling area between adjacent dielectric layers, wherein the remained first initial conductive layer forms a first intermediate conductive layer, the remained second initial conductive layer forms a second intermediate conductive layer, and the top surface of the end part of the first intermediate conductive layer positioned in the connecting hole is flush with the top surface of the end part of the second intermediate conductive layer positioned in the connecting hole and is lower than the top surface of the sacrificial layer;

removing the first photoresist layer;

and removing part of the first intermediate conductive layer and part of the second intermediate conductive layer on the sacrificial layer, wherein the remained first intermediate conductive layer forms a first conductive layer, the remained second intermediate conductive layer forms a second conductive layer, and the area of the first conductive layer on the sacrificial layer is larger than that of the second conductive layer on the sacrificial layer.

15. The method for manufacturing an infrared detector as set forth in claim 14, wherein the step of removing a portion of the first intermediate conductive layer and a portion of the second intermediate conductive layer on the sacrificial layer includes:

forming a second photoresist layer in the filling region, wherein the second photoresist layer extends out of the filling region and covers the dielectric layer and a part of the second intermediate conductive layer, and the second photoresist layer has a first projection region on the substrate;

removing the second intermediate conductive layer which is not shielded by the second photoresist layer, wherein the second intermediate conductive layer which is remained forms a second conductive layer;

removing the second photoresist layer;

forming a third photoresist layer in the filling region, wherein the third photoresist layer extends out of the filling region and covers the dielectric layer, the second conductive layer and a part of the first intermediate conductive layer, the third photoresist layer has a second projection region on the substrate, and the area of the second projection region is larger than that of the first projection region;

and removing the first intermediate conductive layer which is not shielded by the third photoresist layer, wherein the remained first intermediate conductive layer forms a first conductive layer, and the first conductive layer and the second conductive layer form a step on the sacrificial layer.

16. The method of claim 12, wherein the step of removing a portion of the first initial conductive layer and a portion of the second initial conductive layer comprises:

forming a fourth photoresist layer in a region surrounded by the second initial conducting layer, wherein the top surface of the fourth photoresist layer is flush with the top surface of the second initial conducting layer;

removing the second initial conducting layer which is not shielded by the fourth photoresist layer and removing part of the second initial conducting layer on the side wall of the connecting hole, wherein the second initial conducting layer which is remained forms a second conducting layer, and the longitudinal section of the second conducting layer is U-shaped;

removing the fourth photoresist layer;

forming a fifth photoresist layer in a region surrounded by the second conductive layer and the first initial conductive layer, wherein the fifth photoresist layer also covers the first initial conductive layer;

patterning the fifth photoresist layer to form a second opening in the fifth photoresist layer, wherein the second opening exposes a region between two adjacent connecting holes and a part of the first initial conducting layer;

and removing the first initial conducting layer exposed in the second opening, wherein the first initial conducting layer which is remained forms the first conducting layer, the first conducting layer comprises a first supporting layer and a first bridge deck connected with the first supporting layer, the first bridge deck is arranged on the sacrificial layer, and the longitudinal section of the first supporting layer is U-shaped.

17. The method for manufacturing an infrared detector as set forth in claim 10, wherein the step of forming the microbridge structure includes:

forming a first initial conducting layer in the connecting hole, wherein the first initial conducting layer covers the sacrificial layer;

removing part of the first initial conducting layer on the sacrificial layer and in the connecting hole, wherein the first initial conducting layer which is remained forms a first conducting layer, the longitudinal section of the first conducting layer is U-shaped, and the top surface of the end part of the first conducting layer is lower than the top surface of the sacrificial layer;

and forming a second conductive layer on the first conductive layer, wherein one end of the second conductive layer extends out of the connecting hole and covers part of the sacrificial layer.

18. The method for manufacturing an infrared detector as claimed in claim 17, wherein the first conductive layer includes two sub-conductive layers stacked in sequence, and the two sub-conductive layers are made of different materials.

19. The method for manufacturing an infrared detector as set forth in claim 18, wherein the step of forming a second conductive layer on the first conductive layer comprises:

forming a second initial conductive layer on the first conductive layer, the second initial conductive layer further overlying the sacrificial layer;

forming a sixth photoresist layer, wherein the sixth photoresist layer is internally provided with a third opening, and the third opening exposes the second initial conductive layer between the adjacent connecting holes and the part of the second initial conductive layer;

and removing the second initial conductive layer exposed in the third opening, wherein the second initial conductive layer remained forms a second conductive layer.

20. The method for manufacturing an infrared detector as set forth in any one of claims 10 to 19, wherein after the step of forming a plurality of microbridge structures, the method for manufacturing further comprises:

forming an initial protection layer on the second conductive layer, wherein the initial protection layer also covers the sacrificial layer;

and removing the initial protective layer on the sacrificial layer between the adjacent connecting holes, wherein the remained initial protective layer forms a protective layer.

Technical Field

The application relates to the technical field of semiconductors, in particular to an infrared detector and a preparation method thereof.

Background

The infrared detector is a device for converting an incident infrared radiation signal into an electrical signal and outputting the electrical signal, and generally includes an Integrated Circuit (IC), a microbridge structure and devices disposed on a surface of the microbridge structure, where the IC is an infrared signal processing Circuit, the microbridge structure is an infrared sensing device, the microbridge structure generally includes a supporting portion and a microbridge deck portion, the supporting portion is used for realizing connection and supporting of the electrical signal, and the microbridge deck portion is used for sensing the infrared signal.

When the microbridge structure is manufactured, a sacrificial layer is usually formed on a substrate, a connection hole is formed in the sacrificial layer, then the microbridge structure is formed in the connection hole, the microbridge structure extends out of the connection hole and covers the sacrificial layer, and the microbridge structure is utilized to realize the electrical connection between an integrated circuit in the substrate and a device on a conductive layer formed subsequently.

However, the microbridge structure has a high resistance, which degrades the performance of the infrared detector.

Disclosure of Invention

In view of the above problems, embodiments of the present application provide an infrared detector and a method for manufacturing the same, which reduce the resistance of a microbridge structure and improve the performance of the infrared detector.

In order to achieve the above object, the embodiments of the present application provide the following technical solutions:

a first aspect of embodiments of the present application provides an infrared detector, which includes: comprises a substrate, a sacrificial layer and a micro-bridge structure;

the sacrificial layer is arranged on the substrate, and a connecting hole is formed in the sacrificial layer;

the micro-bridge structure is partially arranged in the connecting hole, and the micro-bridge structure positioned in the connecting hole is electrically connected with a circuit arranged in the substrate, wherein the micro-bridge structure comprises a first conducting layer and a second conducting layer which are arranged in a stacked mode, and the first conducting layer is connected with the inner wall of the connecting hole.

The infrared detector as set forth above, wherein said first conductive layer comprises a first support layer and a first bridge deck connected to said first support layer, said first bridge deck overlying a portion of said sacrificial layer;

the first supporting layer is arranged in the connecting hole, and the top surface of the end part of the first bridge deck, which deviates from the first bridge deck, is lower than the top surface of the sacrificial layer.

The infrared detector as set forth above, wherein said second conductive layer comprises a second support layer and a second bridge deck connected to said second support layer, said second bridge deck being disposed on said first bridge deck;

the second supporting layer is arranged in the connecting hole, and the top surface of the end part of the second bridge deck deviated from the second supporting layer is flush with the top surface of the end part of the first bridge deck deviated from the first supporting layer.

The infrared detector as set forth above, wherein a projected area of said second bridge deck on said substrate is smaller than a projected area of said first bridge deck on said substrate.

The infrared detector as described above, further comprising a dielectric layer, wherein the dielectric layer is filled in the region surrounded by the second conductive layer, and a top surface of the dielectric layer is flush with a top surface of the second bridge deck.

The infrared detector as set forth above, wherein the second conductive layer is disposed in the connecting hole, and a cross section perpendicular to the substrate is a longitudinal section, the longitudinal section of the second conductive layer is U-shaped, and a top surface of an end portion of the second conductive layer is lower than a top surface of the sacrificial layer.

The infrared detector as described above, wherein the first conductive layer is disposed in the connecting hole, and a top surface of an end portion of the first conductive layer is lower than a top surface of the sacrificial layer;

the second conducting layer covers the first conducting layer, one end of the second conducting layer extends out of the connecting hole and covers part of the sacrificial layer.

The infrared detector as described above, wherein the first conductive layer includes two sub-conductive layers stacked in sequence, and the two sub-conductive layers are made of different materials.

The infrared detector as set forth above, wherein the infrared detector further comprises a protective layer covering the sacrificial layer and the top surface of the microbridge structure;

or the protective layer covers the sacrificial layer, the micro-bridge structure and the top surface of part of the dielectric layer.

A second aspect of the embodiments of the present application provides a method for manufacturing an infrared detector, which includes the following steps:

providing a substrate;

forming a sacrificial layer on the substrate, wherein the sacrificial layer is internally provided with a connecting hole, and the connecting hole exposes part of the substrate;

and forming a micro-bridge structure, wherein part of the micro-bridge structure is arranged in the connecting hole, the micro-bridge structure comprises a first conducting layer and a second conducting layer which are arranged in a stacked mode, and the first conducting layer is connected with the inner wall of the connecting hole.

The method for manufacturing an infrared detector as described above, wherein the step of forming a sacrificial layer on the substrate includes:

forming a mask layer on the sacrificial layer;

patterning the mask layer to form a plurality of mask openings arranged at intervals in the mask layer;

removing the sacrificial layer exposed in each mask opening to form a plurality of connecting holes arranged at intervals in the sacrificial layer;

the step of forming the microbridge structure includes:

forming a plurality of microbridge structures, a portion of each of the microbridge structures being disposed within one of the connecting apertures.

The method for manufacturing an infrared detector as described above, wherein the step of forming a plurality of microbridge structures includes:

forming a first initial conducting layer and a second initial conducting layer which are sequentially stacked in the connecting hole, wherein the first initial conducting layer and the second initial conducting layer extend out of the connecting hole and cover the sacrificial layer;

and removing part of the first initial conducting layer and part of the second initial conducting layer, wherein the remained first initial conducting layer forms a first conducting layer, the remained second initial conducting layer forms a second conducting layer, and at least one of the first conducting layer and the second conducting layer extends out of the connecting hole and covers part of the sacrificial layer.

The method for manufacturing an infrared detector as described above, wherein after the step of forming the first initial conductive layer and the second initial conductive layer stacked in sequence in the connection hole, and before the step of removing a part of the first initial conductive layer and a part of the second initial conductive layer, the method further includes:

forming a dielectric layer in a region surrounded by the second initial conducting layer, wherein the top surface of the dielectric layer is flush with the top surface of the second initial conducting layer;

and forming a first photoresist layer on the second initial conducting layer and the dielectric layers, wherein the first photoresist layer is internally provided with a first opening, and the first opening exposes the area between the adjacent dielectric layers and a part of the area of each dielectric layer.

The method for manufacturing an infrared detector, wherein the step of removing a portion of the first initial conductive layer and a portion of the second initial conductive layer includes:

removing a part of the first initial conductive layer and a part of the second initial conductive layer exposed in the first opening so as to form a filling area between adjacent dielectric layers, wherein the remained first initial conductive layer forms a first intermediate conductive layer, the remained second initial conductive layer forms a second intermediate conductive layer, and the top surface of the end part of the first intermediate conductive layer positioned in the connecting hole is flush with the top surface of the end part of the second intermediate conductive layer positioned in the connecting hole and is lower than the top surface of the sacrificial layer;

removing the first photoresist layer;

and removing part of the first intermediate conductive layer and part of the second intermediate conductive layer on the sacrificial layer, wherein the remained first intermediate conductive layer forms a first conductive layer, the remained second intermediate conductive layer forms a second conductive layer, and the area of the first conductive layer on the sacrificial layer is larger than that of the second conductive layer on the sacrificial layer.

The method for manufacturing an infrared detector, wherein the step of removing a portion of the first intermediate conductive layer and a portion of the second intermediate conductive layer on the sacrificial layer includes:

forming a second photoresist layer in the filling region, wherein the second photoresist layer extends out of the filling region and covers the dielectric layer and a part of the second intermediate conductive layer, and the second photoresist layer has a first projection region on the substrate;

removing the second intermediate conductive layer which is not shielded by the second photoresist layer, wherein the second intermediate conductive layer which is remained forms a second conductive layer;

removing the second photoresist layer;

forming a third photoresist layer in the filling region, wherein the third photoresist layer extends out of the filling region and covers the dielectric layer, the second conductive layer and a part of the first intermediate conductive layer, the third photoresist layer has a second projection region on the substrate, and the area of the second projection region is larger than that of the first projection region;

and removing the first intermediate conductive layer which is not shielded by the third photoresist layer, wherein the remained first intermediate conductive layer forms a first conductive layer, and the first conductive layer and the second conductive layer form a step on the sacrificial layer.

The method for manufacturing an infrared detector, wherein the step of removing a portion of the first initial conductive layer and a portion of the second initial conductive layer includes:

forming a fourth photoresist layer in a region surrounded by the second initial conducting layer, wherein the top surface of the fourth photoresist layer is flush with the top surface of the second initial conducting layer;

removing the second initial conducting layer which is not shielded by the fourth photoresist layer and removing part of the second initial conducting layer on the side wall of the connecting hole, wherein the second initial conducting layer which is remained forms a second conducting layer, and the longitudinal section of the second conducting layer is U-shaped;

removing the fourth photoresist layer;

forming a fifth photoresist layer in a region surrounded by the second conductive layer and the first initial conductive layer, wherein the fifth photoresist layer also covers the first initial conductive layer;

patterning the fifth photoresist layer to form a second opening in the fifth photoresist layer, wherein the second opening exposes a region between two adjacent connecting holes and a part of the first initial conducting layer;

and removing the first initial conducting layer exposed in the second opening, wherein the first initial conducting layer which is remained forms the first conducting layer, the first conducting layer comprises a first supporting layer and a first bridge deck connected with the first supporting layer, the first bridge deck is arranged on the sacrificial layer, and the longitudinal section of the first supporting layer is U-shaped.

The method for manufacturing an infrared detector as described above, wherein the step of forming a plurality of microbridge structures includes:

forming a first initial conducting layer in the connecting hole, wherein the first initial conducting layer covers the sacrificial layer;

removing part of the first initial conducting layer on the sacrificial layer and in the connecting hole, wherein the first initial conducting layer which is remained forms a first conducting layer, the longitudinal section of the first conducting layer is U-shaped, and the top surface of the end part of the first conducting layer is lower than the top surface of the sacrificial layer;

and forming a second conductive layer on the first conductive layer, wherein one end of the second conductive layer extends out of the connecting hole and covers part of the sacrificial layer.

The preparation method of the infrared detector, wherein the first conductive layer comprises two sub-conductive layers which are sequentially stacked, and the two sub-conductive layers are made of different materials.

The method for manufacturing an infrared detector, wherein the step of forming a second conductive layer on the first conductive layer includes:

forming a second initial conductive layer on the first conductive layer, the second initial conductive layer further overlying the sacrificial layer;

forming a sixth photoresist layer, wherein the sixth photoresist layer is internally provided with a third opening, and the third opening exposes the second initial conductive layer between the adjacent connecting holes and the part of the second initial conductive layer;

and removing the second initial conductive layer exposed in the third opening, wherein the second initial conductive layer remained forms a second conductive layer.

The method for manufacturing an infrared detector as described above, wherein, after the step of forming a plurality of microbridge structures, the method further comprises:

forming an initial protection layer on the second conductive layer, wherein the initial protection layer also covers the sacrificial layer;

and removing the initial protective layer on the sacrificial layer between the adjacent connecting holes, wherein the remained initial protective layer forms a protective layer.

In the infrared detector and the preparation method thereof provided by the embodiment of the application, the microbridge structure is improved, so that the microbridge structure comprises the first conducting layer and the second conducting layer which are stacked, and compared with the technical scheme that the microbridge structure only comprises one conducting layer in the related technology, the thickness of the microbridge structure is increased, the resistance of the microbridge structure is further reduced, and the performance of the infrared detector is improved.

Drawings

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

Fig. 1 is a process flow diagram of a method for manufacturing an infrared detector according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a substrate and a sacrificial layer formed in a method for manufacturing an infrared detector according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of forming a first initial conductive layer and a second initial conductive layer in a method for manufacturing an infrared detector according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of an initial dielectric layer formed in a method for manufacturing an infrared detector according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of a dielectric layer formed in a method for manufacturing an infrared detector provided in an embodiment of the present application;

fig. 6 is a schematic structural diagram of a first photoresist layer formed in a method for manufacturing an infrared detector according to an embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of forming a first intermediate conductive layer and a second intermediate conductive layer in a method for manufacturing an infrared detector according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of removing the first photoresist layer in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 9 is a schematic structural diagram of forming a second photoresist layer in the method for manufacturing an infrared detector according to an embodiment of the present application;

fig. 10 is a first schematic structural diagram illustrating a second conductive layer formed in the method for manufacturing an infrared detector according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of forming a third photoresist layer in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 12 is a first schematic structural diagram illustrating a second conductive layer formed in the method for manufacturing an infrared detector according to an embodiment of the present application;

fig. 13 is a schematic structural diagram of forming a fourth photoresist layer in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 14 is a second schematic structural diagram illustrating a second conductive layer formed in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 15 is a schematic structural diagram of a fifth photoresist layer formed in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 16 is a second schematic structural diagram illustrating a first conductive layer formed in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 17 is a third schematic structural diagram illustrating a first conductive layer formed in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 18 is a second schematic structural diagram illustrating a second initial conductive layer formed in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 19 is a schematic structural diagram of a sixth photoresist layer formed in the method for manufacturing an infrared detector according to an embodiment of the present application;

fig. 20 is a third structural view of a second initial conductive layer formed in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 21 is a first schematic structural diagram illustrating a formation of an initial protection layer in a method for manufacturing an infrared detector according to an embodiment of the present disclosure;

fig. 22 is a second schematic structural diagram illustrating a formation of an initial protection layer in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 23 is a third schematic structural diagram illustrating formation of an initial protection layer in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 24 is a first schematic structural diagram illustrating a protective layer formed in the method for manufacturing an infrared detector according to an embodiment of the present disclosure;

fig. 25 is a second schematic structural diagram illustrating a protective layer formed in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 26 is a third schematic structural diagram illustrating a protective layer formed in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 27 is a schematic structural diagram of a seventh photoresist layer formed in the method for manufacturing an infrared detector according to the embodiment of the present application;

fig. 28 is a schematic structural diagram of removing a part of the initial protection layer in the method for manufacturing an infrared detector according to the embodiment of the present application.

Description of reference numerals:

10: a substrate; 20: a sacrificial layer; 21: connecting holes; 30: a microbridge structure; 31: a first conductive layer; 311: a first support layer; 312: a first deck; 313: a sub-conductive layer; 32: a second conductive layer; 321: a second support layer; 322: a second deck; 33: a first initial conductive layer; 34: a second initial conductive layer; 35: a first intermediate conductive layer; 36: a second intermediate conductive layer; 40: a dielectric layer; 41: a filling area; 42: an initial dielectric layer; 50: a protective layer; 51: an initial protective layer; 60: a first photoresist layer; 61: a first opening; 70: a second photoresist layer; 80: a third photoresist layer; 90: a fourth photoresist layer; 100: a fifth photoresist layer; 101: a second opening; 110: a sixth photoresist layer; 111: a third opening; 120: a seventh photoresist layer; 121: a fourth opening.

Detailed Description

As described in the background art, the micro-bridge structure in the related art has a technical problem of large resistance, and the inventors have found that the problem occurs because the micro-bridge structure generally includes a conductive layer, and the conductive layer is made of a thin aluminum film, so that the resistance of the conductive layer is large, and further, the resistance of the micro-bridge structure is increased, and the performance of the infrared detector is reduced.

To above-mentioned technical problem, in this application embodiment, through improving the microbridge structure for the microbridge structure is including range upon range of first conducting layer and the second conducting layer that sets up, and in the correlation technique, the microbridge structure only includes the technical scheme of one deck conducting layer and compares, has increased the thickness of microbridge structure, and then has reduced the resistance of microbridge structure, has improved infrared detector's performance.

In order to make the aforementioned objects, features and advantages of the embodiments of the present application more comprehensible, embodiments of the present application are described in detail below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

As shown in fig. 1, an embodiment of the present application provides a method for manufacturing an infrared detector, including the following steps:

step S100: a substrate is provided.

Illustratively, as shown in fig. 2, the substrate 10 serves as a supporting component of the infrared detector for supporting other components disposed thereon, wherein the substrate 10 may be made of a semiconductor material, and the semiconductor material may be one or more of silicon, germanium, a silicon germanium compound and a silicon carbon compound.

Step S200: a sacrificial layer is formed on a substrate, and a connection hole is formed in the sacrificial layer and exposes a part of the substrate.

In this embodiment, the number of the connection holes may be set according to the structure of the infrared detector, for example, the number of the connection holes may be one or multiple, and when the number of the connection holes 21 is multiple, the following process may be adopted for preparation:

first, the sacrificial layer 20 may be formed on the substrate 10 using a deposition process, such as forming the sacrificial layer 20 on the substrate 10 using a chemical vapor deposition process or a physical vapor deposition process.

Then, a mask layer (not shown) is formed on the sacrificial layer 20.

And patterning the mask layer to form a plurality of mask openings arranged at intervals in the mask layer.

The sacrificial layer 20 exposed in each mask opening is removed by using an etching gas or an etching liquid to form a plurality of connection holes 21 in the sacrificial layer 20, the plurality of connection holes 21 may be spaced in a first direction, and each connection hole 21 may expose a portion of the substrate 10, which is shown in fig. 2.

In this embodiment, the first direction may be an X direction in fig. 2.

The material of the sacrificial layer 20 may include an insulating material such as silicon dioxide or polyimide.

Step S300: and forming a micro-bridge structure, wherein part of the micro-bridge structure is arranged in the connecting hole, the micro-bridge structure comprises a first conducting layer and a second conducting layer which are arranged in a stacked mode, and the first conducting layer is connected with the inner wall of the connecting hole.

In this embodiment, the number of the micro-bridge structures is also one when the number of the connection holes is one, and the number of the micro-bridge structures is also plural when the number of the connection holes is plural.

It should be noted that, part of the microbridge structure is disposed in the connecting hole, and it is understood that only part of the microbridge structure is disposed in the connecting hole, and not all of the microbridge structure is disposed in the connecting hole.

Illustratively, as shown in fig. 3, a first initial conductive layer 33 and a second initial conductive layer 34 are formed in the connection hole 21 in a stacked manner in this order, and both the first initial conductive layer 33 and the second initial conductive layer 34 extend out of the connection hole 21 and cover the sacrificial layer 20.

In the present embodiment, an atomic layer deposition process may be used to form the first initial conductive layer 33 and the second initial conductive layer 34 in the connection hole 21, wherein a material of the first initial conductive layer 33 may include a conductive material such as titanium nitride, and a material of the second initial conductive layer 34 may include a conductive material such as aluminum or tungsten.

After the first initial conductive layer 33 and the second initial conductive layer 34 are formed, a part of the first initial conductive layer 33 and a part of the second initial conductive layer 34 are removed, the remaining first initial conductive layer 33 forms the first conductive layer 31, the remaining second initial conductive layer 34 forms the second conductive layer 32, and at least one of the first conductive layer 31 and the second conductive layer 32 extends out of the connection hole 21 and covers the sacrificial layer 20.

It should be noted that, in this embodiment, the first conductive layer 31 and the second conductive layer 32 may extend out of the connection hole 21 at the same time, or one of the first conductive layer 31 and the second conductive layer 32 may extend into the connection hole, and as to the form in which the first conductive layer and the second conductive layer are disposed, the positional relationship between the first conductive layer and the second conductive layer will be described in detail below with reference to the drawings.

As a possible way to prepare the microbridge structure, as shown in fig. 4 and 5, an initial dielectric layer 42 is formed in the region surrounded by the second initial conductive layer 34, and then the initial dielectric layer 42 is planarized by using a chemical mechanical polishing process, and the remaining initial dielectric layer 42 forms the dielectric layer 40, wherein the top surface of the dielectric layer 40 is flush with the top surface of the second initial conductive layer 34.

After the initial dielectric layers 42 are planarized, as shown in fig. 6, a first photoresist layer 60 with a certain thickness may be formed on the second initial conductive layer 34 and the dielectric layers 40 by a coating method, and then the first photoresist layer 60 is patterned by an exposure, development or etching method, so that first openings 61 are formed in the first photoresist layer, and the first openings 61 expose regions between adjacent dielectric layers 40 and a portion of each dielectric layer 40.

Taking the orientation shown in fig. 6 as an example, in the present embodiment, two connection holes and three protrusions for separating the two connection holes are disposed in the substrate, for convenience of describing the exposed region of the first opening, the three protrusions may be respectively marked as a first protrusion, a second protrusion and a third protrusion from left to right, and the first opening may expose the second protrusion and partial regions in the two connection holes located at the left and right sides of the second protrusion.

Since the reflectivity of the second initial conductive layer 34 is large, when removing portions of the first and second initial conductive layers 33 and 34, it is difficult to remove the second initial conductive layer and the first initial conductive layer on the second bump, therefore, in the present embodiment, by forming the dielectric layer in the region surrounded by the second initial conductive layer, the reflectivity of the dielectric layer is small, the first opening can be dimensioned larger, so that the area of the area exposed by the first opening is also increased, thus, when the first initial conductive layer and the second initial conductive layer in the area are removed by a wet process with high selection ratio, the first initial conducting layer and the second initial conducting layer in other areas can be protected through the dielectric layer, the etching liquid is prevented from damaging metals in other areas, and the photoetching problem caused by small size and strong reflection in the traditional scheme is solved.

After the first opening is formed, as shown in fig. 7, an etching solution or an etching gas is used to remove a portion of the first initial conductive layer 33 and a portion of the second initial conductive layer 34 exposed in the first opening 61, so as to form a filling region 41 between the adjacent dielectric layers 40, the remaining first initial conductive layer 33 forms a first intermediate conductive layer 35, the remaining second initial conductive layer 34 forms a second intermediate conductive layer 36, and the top surfaces of the first intermediate conductive layer 35 and the second intermediate conductive layer 36 at the end of the connection hole are flush with each other and lower than the top surface of the sacrificial layer 20, that is, the top surface of the first intermediate conductive layer 35 exposed in the filling region 41 is flush with the top surface of the second intermediate conductive layer 36.

Thereafter, as shown in fig. 8, the first photoresist layer 60 is removed using a cleaning solution.

Finally, a part of the first intermediate conductive layer 35 and a part of the second intermediate conductive layer 36 on the sacrificial layer 20 are removed, the remaining first intermediate conductive layer 35 constitutes the first conductive layer 31, the remaining second intermediate conductive layer 36 constitutes the second conductive layer 32, and the area of the first conductive layer 31 on the sacrificial layer 20 is larger than the area of the second conductive layer 32 on the sacrificial layer 20.

Illustratively, as shown in fig. 9, first, a second photoresist layer 70 is formed in the filling region 41, the second photoresist layer 70 extends to the outside of the filling region 41 and covers the dielectric layer 40 and a portion of the second intermediate conductive layer 36, and the second photoresist layer 70 has a first projection area on the substrate 10.

Next, as shown in fig. 10, the second intermediate conductive layer 36 not covered by the second photoresist layer 70 is removed by using an etching liquid or an etching gas, and the remaining second intermediate conductive layer 36 constitutes a second conductive layer 32, which includes a second support layer located in the connecting hole and a second bridge surface located on the sacrificial layer.

Thereafter, the second photoresist layer 70 is removed using a cleaning solution.

After removing the second photoresist layer 70, as shown in fig. 11, a third photoresist layer 80 is formed in the filling region 41, the third photoresist layer 80 extends to the outside of the filling region 41 and covers the dielectric layer 40, the second conductive layer 32 and a portion of the first intermediate conductive layer 35, the third photoresist layer 80 has a second projection region on the substrate 10, and the area of the second projection region is larger than that of the first projection region.

Finally, as shown in fig. 12, the first intermediate conductive layer 35 which is not covered by the third photoresist layer 80 is removed, the remaining first intermediate conductive layer 35 constitutes the first conductive layer 31, the first conductive layer 31 includes a first support layer 311 disposed in the connecting hole and a first bridge deck 312 connected to the first support layer 311, the first bridge deck 312 is disposed on the sacrificial layer 20, wherein the area of the first bridge deck 312 is larger than that of the second bridge deck 322, so that the first conductive layer 31 forms a step with the portion of the second conductive layer 32 on the sacrificial layer.

In this embodiment, one part of the first conductive layer and the second conductive layer is disposed in the connecting hole, and the other part of the first conductive layer and the second conductive layer is disposed on the sacrificial layer, so that the second conductive layer covers the first conductive layer to increase the thickness of the conductive layer, reduce the resistance of the conductive layer to the maximum extent, further reduce the resistance of the microbridge structure, and improve the performance of the infrared detector.

In addition, in the embodiment, one end of the first conducting layer and one end of the second conducting layer extend out of the connecting hole, so that the area of the micro-bridge structure for forming the step on the sacrificial layer is reduced, and the difficulty of deposition or photoetching process in the subsequent process of forming other film layers on the sacrificial layer is reduced.

If the area of the first conductive layer on the sacrificial layer is equal to the area of the second conductive layer on the sacrificial layer, the height difference between the sacrificial layer and the conductive layer is increased, and the height difference affects the subsequent deposition or etching process.

As another possible way to prepare the microbridge structure, as shown in fig. 13, a fourth photoresist layer 90 is formed in the region surrounded by the second initial conductive layer 34, the fourth photoresist layer 90 fills the region surrounded by the second initial conductive layer 34, and the top surface of the fourth photoresist layer 90 is flush with the top surface of the second initial conductive layer 34.

Thereafter, as shown in fig. 14, the second initial conductive layer 34 not covered by the fourth photoresist layer 90 is removed, and a portion of the second initial conductive layer 34 on the sidewall of the connection hole 21 is removed, the remaining second initial conductive layer 34 forms a second conductive layer 32, the second conductive layer 32 has a U-shaped longitudinal cross section, and the top surface of the end portion of the second conductive layer 32 is lower than the top surface of the sacrificial layer 20.

After the second conductive layer 32 is formed, the fourth photoresist layer is removed by using a cleaning solution.

Thereafter, as shown in fig. 15, a fifth photoresist layer 100 is formed in the region enclosed by the second conductive layer 32 and the first initial conductive layer 33, and the fifth photoresist layer 100 further covers the first initial conductive layer 33.

The fifth photoresist layer 100 is patterned to form a second opening 101 in the fifth photoresist layer 100, and the second opening 101 exposes a region between two adjacent connection holes and a portion of the first preliminary conductive layer 33.

The second opening 101 exposes the entire first preliminary conductive layer 33 on the second bump and a portion of the first preliminary conductive layer 33 on the first bump and the third bump.

As shown in fig. 16, the first initial conductive layer 33 exposed in the second opening 101 may be removed by using an etching liquid or an etching gas, the first initial conductive layer 33 remaining constitutes the first conductive layer 31, the first conductive layer 31 includes a first support layer 311 and a first bridge deck 312 connected to the first support layer 311, the first bridge deck 312 is disposed on the sacrificial layer 20, and the longitudinal cross-sectional shape of the first support layer 311 is U-shaped.

It should be noted that, in this embodiment, the top surface of the end of the first support layer 311 facing away from the first bridge deck 312 is flush with or not flush with the top surface of the end of the second conductive layer 32 facing away from the first bridge deck 312.

Taking the orientation shown in fig. 16 as an example, the end surface of the first supporting layer 311 near the second protrusion is flush with or lower than the end surface of the second conductive layer near the second protrusion.

In this embodiment, only the first conductive layer in the micro-bridge structure 30 has a bridge deck structure, i.e. only a part of the first conductive layer 31 is located on the sacrificial layer 20, which ensures that the high resistance metal and the vacuum matching in the micro-bridge area are ensured while reducing the electrical resistance of the micro-bridge structure.

In addition, the thickness difference between the sacrificial layer 20 and the first conductive layer 31 can be reduced to the maximum extent, and the height difference between the sacrificial layer and the conductive layer can be reduced, so that the subsequent deposition or etching process can be performed normally.

As another possible way to prepare the microbridge structure, a first initial conductive layer 33 is formed in the connection hole 21, and the first initial conductive layer 33 covers the sacrificial layer 20, it should be noted that, in this embodiment, the first initial conductive layer 33 is a stacked structure, for example, the first initial conductive layer 33 includes two first sub-initial conductive layers stacked one on another, and the structure of this first sub-initial conductive layer can be continued with reference to fig. 3.

As shown in fig. 17 and 18, a portion of the first initial conductive layer 33 on the sacrificial layer 20 and in the connection hole 21 is removed, the remaining first initial conductive layer 33 forms a first conductive layer 31, the first conductive layer 31 has a U-shaped longitudinal cross section, and the top surface of the first conductive layer 31 is lower than the top surface of the sacrificial layer, wherein the first conductive layer 31 includes two sub-conductive layers 313 stacked in sequence, the two sub-conductive layers 313 are made of different materials, one sub-conductive layer 313 includes titanium nitride, and the other sub-conductive layer 313 includes tungsten or aluminum.

After the first conductive layer is formed, a second conductive layer 32 is formed on the first conductive layer 31 by a deposition process, and one end of the second conductive layer 32 extends to the outside of the connection hole 21 and covers a part of the sacrificial layer 20.

Illustratively, as shown in fig. 18, first, a second initial conductive layer 34 is formed on the first conductive layer 31, and the second initial conductive layer 34 also covers the sacrificial layer 20.

Next, as shown in fig. 19, a sixth photoresist layer 110 is formed, the sixth photoresist layer 110 having a third opening 111 therein, the third opening 111 exposing portions of the second initial conductive layer 34 and the remaining second initial conductive layer 34 between the adjacent connection holes 21.

It should be noted that, in this embodiment, the remaining portion of the second initial conductive layer 34 may be understood as a portion of the second initial conductive layer on the first bump and a portion of the second initial conductive layer on the second bump.

Finally, as shown in fig. 20, the second initial conductive layer 34 exposed in the third opening 111 is removed, and the remaining second initial conductive layer 34 constitutes the second conductive layer 32.

In the present embodiment, in forming the microbridge structure, the longitudinal section of the first conductive layer 31 is formed in a U shape, and the first conductive layer 31 is disposed on the bottom wall and a part of the side wall of the connection hole 21, and the second conductive layer 32 is disposed on the bottom wall and the side wall of the connection hole 21 and a part of the sacrificial layer 20.

Only the portion of the second conductive layer 32 in the micro-bridge structure 30 is located on the sacrificial layer 20, so that the thickness difference between the sacrificial layer 20 and the second conductive layer 32 can be reduced to the greatest extent, and the height difference between the sacrificial layer and the conductive layer can be reduced, so as to facilitate the normal operation of the subsequent deposition or etching process.

In some embodiments, after the step of forming the plurality of microbridge structures, the method of manufacturing an infrared detector further includes:

as shown in fig. 21, 22 and 23, an initial protective layer 51 is formed on the second conductive layer 32, and the initial protective layer 51 also covers the sacrificial layer 20.

The material of the initial protection layer comprises at least one of silicon dioxide, silicon oxynitride, silicon nitride or silicon carbide.

As shown in fig. 24 to 26, the initial protective layer 51 on the sacrificial layer 20 between the adjacent connection holes 21 is removed, and the remaining initial protective layer 51 constitutes the protective layer 50.

How to form the protective layer is described in detail below by taking one of the microbridge structures as an example, as shown in fig. 27 and 28.

Forming a seventh photoresist layer 120 on the initial protection layer 51, wherein the seventh photoresist layer 120 has a fourth opening 121, the fourth opening 121 exposes a region between the adjacent dielectric layers 40 and a part of the dielectric layers 40, then removing the initial protection layer 51 exposed in the fourth opening by using etching gas or etching liquid, and the remaining initial protection layer 51 forms a protection layer.

The protection layer is arranged to protect the microbridge structure, damage to the microbridge structure in a subsequent etching process is prevented, and performance of the infrared detector is improved.

An embodiment of the present application further provides an infrared detector, as shown in fig. 24, 25, and 26, including: a substrate 10, a sacrificial layer 20, and a plurality of microbridge structures 30.

The sacrificial layer 20 is disposed on the substrate 10, and the sacrificial layer 20 has a plurality of connection holes 21, the plurality of connection holes 21 are disposed at intervals in a first direction, and each of the connection holes 21 exposes a portion of the substrate 10.

A portion of each micro-bridge structure 30 is disposed in one of the connection holes 21, and the micro-bridge structure 30 located in the connection hole 21 is electrically connected to a circuit disposed in the substrate 10, wherein the micro-bridge structure 30 includes a first conductive layer 31 and a second conductive layer 32 which are stacked, and the first conductive layer 31 is connected to an inner wall of the connection hole 21.

It should be noted that, in the present embodiment, a portion of each micro-bridge structure 30 is disposed in one connection hole, and it is understood that only a portion of the micro-bridge structure is disposed in the connection hole, and not all the micro-bridge structures are disposed in the connection hole, or a portion of the first conductive layer is disposed outside the connection hole, or a portion of the second conductive layer is disposed outside the connection hole, or portions of the first conductive layer and the second conductive layer are disposed outside the connection hole.

In the embodiment of the application, the microbridge structure is improved, so that the microbridge structure comprises the first conducting layer and the second conducting layer which are stacked, and compared with the technical scheme that the microbridge structure only comprises one conducting layer in the related technology, the thickness of the microbridge structure is increased, the resistance of the microbridge structure is reduced, and the performance of the infrared detector is improved. In addition, the strength of the micro-bridge structure can be increased, and the structural characteristics of the whole micro-bridge structure can be better controlled.

As a possible embodiment of the micro-bridge structure, as shown in fig. 24, the first conductive layer 31 includes a first support layer 311 and a first bridge deck 312 connected to the first support layer 311, the first bridge deck 312 covers a portion of the sacrificial layer 20, and a top surface of an end of the first support layer 311 facing away from the first bridge deck 312 is lower than a top surface of the sacrificial layer 20.

The second conductive layer 32 comprises a second support layer 321 and a second bridge deck 322 connected to the second support layer 321, the second bridge deck 322 is disposed on the first bridge deck 312, and a top surface of an end of the second support layer 321 facing away from the second bridge deck 322 is flush with a top surface of an end of the first support layer 311 facing away from the first bridge deck 312.

In this embodiment, the first conductive layer 31 is disposed on the bottom wall and the side wall of the connection hole 21 and part of the top surface of the sacrificial layer 20, and the second conductive layer 32 is also disposed on the bottom wall and the side wall of the connection hole 21 and part of the top surface of the sacrificial layer 20, so that one end of the first conductive layer 31 and one end of the second conductive layer 32 extend onto the sacrificial layer.

Further, a projected area of the second bridge deck 322 on the base 10 is smaller than a projected area of the first bridge deck 312 on the base 10, so that a step is formed between the second bridge deck 322 and the first bridge deck 312.

If the area of the first conductive layer on the sacrificial layer is equal to the area of the second conductive layer on the sacrificial layer, the height difference between the sacrificial layer and the conductive layer is increased, and the height difference affects the subsequent deposition or etching process.

In some embodiments, the infrared detector further comprises a dielectric layer 40, the dielectric layer 40 is filled in the area surrounded by the second conductive layer 32, and the top surface of the dielectric layer 40 is flush with the top surface of the second bridge deck 322.

Because the reflectivity of the second initial conducting layer is relatively large, when part of the first initial conducting layer and the second initial conducting layer is removed, the part of the second protrusion is difficult to remove, and therefore, in the embodiment, the dielectric layer is formed in the area surrounded by the second initial conducting layer, and the reflectivity of the dielectric layer is relatively small, the first opening with a relatively large size can be designed, so that the area of the area exposed by the first opening is also increased, and therefore, when the first initial conducting layer and the second initial conducting layer in the area are removed by a high-selectivity wet process, the first initial conducting layer and the second initial conducting layer in other areas can be protected by the dielectric layer, etching liquid is prevented from damaging metals in other areas, and further, the photoetching problem caused by the relatively small size and the relatively strong reflection in the conventional scheme is solved.

As another possible embodiment of the micro-bridge structure 30, as shown in fig. 25, the first conductive layer 31 includes a first support layer 311 and a first bridge deck 312 connected to the first support layer 311, the first bridge deck 312 is covered on the sacrificial layer 20, and a top surface of an end of the first support layer 311 facing away from the first bridge deck 312 is lower than a top surface of the sacrificial layer 20.

The cross section perpendicular to the substrate 10 is taken as a longitudinal section, the longitudinal section of the second conductive layer 32 is U-shaped, and the top surface of the end portion of the second conductive layer 32 is lower than the top surface of the sacrificial layer 20, that is, the top surfaces of the left and right end portions of the second conductive layer 32 are lower than the top surface of the sacrificial layer 20.

It should be noted that the top surface of the end of the second conductive layer 32 away from the first bridge deck 312 and the top surface of the end of the first support layer 311 away from the first bridge deck 312 may be flush or not flush.

In the present embodiment, only the portion of the first conductive layer 31 in the micro-bridge structure 30 is located on the sacrificial layer 20, so that the thickness difference between the sacrificial layer 20 and the micro-bridge structure 30 can be reduced to the maximum extent, so as to facilitate the normal proceeding of the subsequent deposition or etching process.

As still another possible embodiment of the microbridge structure 30, as shown in fig. 26, the first conductive layer 31 is disposed in the connection hole 21, and the top surface of the end portion of the first conductive layer 31 is lower than the top surface of the sacrificial layer 20, that is, the longitudinal cross-sectional shape of the first conductive layer 31 is U-shaped.

The second conductive layer 32 covers the first conductive layer 31, and one end of the second conductive layer 32 extends out of the connection hole 21 and covers a portion of the sacrificial layer 20.

In the present embodiment, only the portion of the second conductive layer 32 in the micro-bridge structure 30 is located on the sacrificial layer 20, so that the thickness difference between the sacrificial layer 20 and the micro-bridge structure 30 can be reduced to the maximum extent, so as to facilitate the normal proceeding of the subsequent deposition or etching process.

Further, the first conductive layer 31 may include two sub-conductive layers 313 stacked in sequence, and the two sub-conductive layers 313 are made of different materials, wherein one sub-conductive layer 313 may include titanium nitride, and the other sub-conductive layer 313 may include tungsten and aluminum.

In this embodiment, the first conductive layer 31 includes two sub-conductive layers 313, which can increase the thickness of the first conductive layer 31, thereby increasing the thickness of the microbridge structure, reducing the resistance of the microbridge structure, and improving the performance of the infrared detector.

In some embodiments, the infrared detector further comprises a protective layer 50, the protective layer 50 covering the sacrificial layer 20 and the top surface of the microbridge structure 30; alternatively, the protective layer 50 covers the top surfaces of the sacrificial layer 20, the microbridge structure 30, and the dielectric layer 40.

The protection layer is arranged to protect the microbridge structure, damage to the microbridge structure in a subsequent etching process is prevented, and performance of the infrared detector is improved.

The embodiments or implementation modes in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

It should be noted that references in the specification to "one embodiment," "an example embodiment," "some embodiments," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.