WO2023141768A1

WO2023141768A1 - Microbolometer and preparation method therefor

Info

Publication number: WO2023141768A1
Application number: PCT/CN2022/073846
Authority: WO
Inventors: 刘继伟; 胡汉林; 甘先锋; 史杰; 王兴祥
Original assignee: 烟台睿创微纳技术股份有限公司
Priority date: 2022-01-25
Filing date: 2022-01-25
Publication date: 2023-08-03

Abstract

The present application provides a microbolometer and a preparation method therefor. In the microbolometer, a getter layer is integrated on a substrate below a bridge surface of a support bridge for supporting a thermally sensitive layer, and the microbolometer and the getter layer can be prepared by using an MEMS process, thereby facilitating optimizing the preparation process of the microbolometer. In addition, the getter layer is arranged inside the microbolometer, so that the microbolometer is not limited by the complexity of a packaging structure and the difficulty of a packaging process, the efficiency of production of the microbolometer can be effectively improved, and the production cost is reduced.

Description

Microbolometer and its preparation method

technical field

The present application relates to the technical field of microelectromechanical system process semiconductor preparation, in particular to a microbolometer and a preparation method thereof.

Background technique

In recent years, thanks to the needs of night vision and security checks, thermal imaging technology represented by uncooled infrared detectors and terahertz detectors has developed rapidly in military, commercial, and industrial fields, especially in the context of the global COVID-19 pandemic. Under the influence of the outbreak, thermal imaging technology has a wide range of needs and applications in the fields of medical treatment and temperature measurement. Both uncooled infrared detectors and terahertz detectors are based on the basic principle of microbolometers, using the photothermal effect to absorb incident electromagnetic radiation, causing temperature changes in internal heat-sensitive materials, and converting electromagnetic radiation into electrical signals for imaging of detectors.

The microbolometer is built on the silicon substrate of the readout circuit, and a series of suspended micro-bridge structures with the same structure are prepared through the micro-electro-mechanical system (MEMS, Micro-Electro-Mechanical System) process. It consists of supporting legs, interconnecting wires and substrates. In order to ensure the sensitivity of the detector, the microbolometer needs to be placed in the sealed cavity, and the getter is used to maintain the vacuum degree of the sealed cavity (generally less than 10-3mbar), so as to reduce the radiation heat caused by heat conduction and heat convection Loss.

At present, the preparation process of the getter is separated from the preparation process of the microbolometer, which is not conducive to reducing the packaging cost of the microbolometer.

technical problem

In order to solve the existing technical problems, an embodiment of the present invention provides a microbolometer with small size and low production cost and a preparation method thereof.

technical solution

The first aspect of the embodiment of the present invention provides a microbolometer, comprising:

A support bridge located on a base, the support bridge is a single-layer or multi-layer bridge, each layer of bridges includes piers and bridge decks, the piers of the bottommost bridge are located on the surface of the base, between adjacent two-layer bridges, the upper The piers of the bridge on one level are located above the deck of the bridge on the next level;

a getter layer on the surface of the substrate and below the deck of the bottommost bridge;

Heat-sensitive layer on the deck of the topmost bridge.

The second aspect of the embodiment of the present invention provides a method for preparing a microbolometer, including:

depositing a getter layer on the substrate;

Form a support bridge on the base, the support bridge is a single-layer or multi-layer bridge, each layer of bridge includes piers and bridge decks, the piers of the bottom bridge are located on the base surface, and the bridge deck of the bottom bridge Located above the getter layer, between two adjacent bridges, the pier of the upper bridge is located above the bridge deck of the lower bridge;

A thermally sensitive layer is deposited on the bridge surface of the topmost bridge.

Beneficial effect

In the microbolometer provided in the above embodiments, the getter layer is integrated on the substrate under the bridge deck of the support bridge used to support the heat-sensitive layer, and the microbolometer and the getter can be prepared by MEMS technology layer, which is conducive to optimizing the preparation process of the microbolometer. In addition, since the getter layer is arranged inside the microbolometer, the microbolometer is not limited by the complexity of the packaging structure and the difficulty of the packaging process, which can effectively improve the production efficiency of the microbolometer and reduce the production cost .

Description of drawings

Fig. 1 is a schematic diagram of a microbolometer provided according to an embodiment of the present application;

Fig. 2 is a schematic top view of a getter layer and a base layer in a microbolometer according to an embodiment of the present application;

Fig. 3 is a schematic top view of a getter layer and a base layer in a microbolometer according to another embodiment of the present application;

Fig. 4 is a schematic flow chart of a preparation method of a microbolometer according to an embodiment of the present application;

5a to 5k are schematic diagrams of various structures formed during the preparation process of the microbolometer preparation method provided according to an embodiment of the present application;

6a to 6c are schematic diagrams of partial structures formed during the preparation process of the microbolometer preparation method provided according to another embodiment of the present application;

Fig. 7 is a schematic diagram of the packaging structure of the microbolometer provided according to the present application.

Embodiments of the present invention

The technical solution of the present application will be further elaborated below in combination with the accompanying drawings and specific embodiments.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the description of the application are only for the purpose of describing specific embodiments, and are not intended to limit the implementation of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the description of this application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", The orientations or positional relationships indicated by "top", "bottom", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, rather than indicating or implying References to devices or elements must have a particular orientation, be constructed, and operate in a particular orientation and therefore should not be construed as limiting the application. In the description of the present application, unless otherwise specified, "plurality" means two or more.

In the description of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediary, and it can be the internal communication of two elements. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application according to specific situations.

The application provides a microbolometer, which mainly includes a substrate, a getter layer, a support layer and a heat sensitive layer. in,

The supporting bridge is located on the base, the supporting bridge is a single-layer or multi-layer bridge, each layer of bridges includes piers and bridge decks, and the piers of the bottommost bridge are located on the surface of the base, between adjacent two-layer bridges, The piers of the bridge on the upper level are located above the deck of the bridge on the next level, the getter layer is located on the surface of the base, and the getter layer located below the deck of the bridge on the lowest level layer, the thermally sensitive layer on the deck of the topmost bridge.

In some embodiments, the substrate is a semiconductor substrate with built-in readout circuits. The base is a semiconductor substrate with a built-in readout circuit, the first region on the surface of the semiconductor substrate has a metal electrode layer electrically connected to the readout circuit, and the pier of the bottommost bridge is located on the metal electrode layer. layer, the getter layer is located in the second region of the surface of the semiconductor substrate, and the first region is located in the periphery of the second region. Therefore, in some embodiments, the microbolometer further comprises a metal connecting layer disposed along the piers and the deck of each bridge of the supporting bridge, the metal connecting layer being on the topmost bridge deck It is in contact with the thermal sensitive layer, and extends along the support bridge to the metal electrode layer in contact with the metal electrode layer. The metal connection layer is used to electrically connect the thermal sensitive layer and the metal electrode layer, so as to realize the readout circuit to read out the detection information of the microbolometer. In other embodiments, the substrate can also be other supporting substrates, so that the MEMS process can be formed on it. After the MEMS process is completed, the other supporting substrates can be removed, and then the electrodes of the microbolometer can be drawn out and read out. Electrode connection of circuit chip.

In the microbolometer provided by the present application, the getter layer is integrated on the substrate under the bridge deck of the support bridge used to support the heat-sensitive layer, and the microbolometer and the getter layer can be prepared by MEMS technology, It is beneficial to optimize the preparation process of the microbolometer. In addition, because the getter layer is arranged inside the microbolometer, the pixel structure of the microbolometer can be optimized, so that the microbolometer is not limited by the complexity of the packaging structure and the difficulty of the packaging process, and the microbolometer can be effectively improved. Measure bolometer production efficiency and reduce production costs.

The microbolometer provided by the application is suitable for single-layer support bridge structure and multi-layer support bridge structure. The microbolometer with a bridge structure (as shown in FIGS. 6a-6c ) is taken as an example to further specifically illustrate the microbolometer provided in the present application and its preparation method. It should be noted here that this application only uses microbolometers with single-layer and two-layer support bridge structures as examples, but this application also applies to microbolometers with three or more layers of support bridge structures.

The present application provides a microbolometer for detecting electromagnetic radiation and a preparation method thereof, and the content of the present application will be described in detail below with reference to FIGS. 1 to 4 and FIGS. 5a to 5k.

As shown in FIG. 1 , in some embodiments, the microbolometer provided by the present application includes a support bridge 7 on the substrate 1, the support bridge 7 is a single-layer support bridge, which is composed of piers and bridge decks, The bridge pier supports the bridge deck on the base 1; and includes a getter layer 4 located on the surface of the base 1 and below the bridge deck of the supporting bridge 7, the microbolometric The gauge also includes a thermally sensitive layer 8 located on the bridge surface of the supporting bridge 7 . Further, the deck of the support bridge 7 is spaced from the getter layer 4 , and the height of the pier of the support bridge is greater than the thickness of the getter layer.

It should be noted that Fig. 1 only illustrates one pixel structure of the microbolometer, but the microbolometer provided in the present application may include a plurality of the pixel structures on the substrate, each of which The pixel structure includes the support bridge 7 , the getter layer 4 and the thermal sensitive layer 8 . In some embodiments, in each of the pixel structures, the piers of the supporting bridges 7 are located at the periphery of the getter layer 4 .

In some embodiments, the supporting bridge 7 in the microbolometer provided by the present application is a dielectric thin film layer of silicon nitride or silicon dioxide or a combination thereof with a thickness of 50nm-500nm and which can absorb electromagnetic radiation, The film layer is a bent film layer, its horizontal part is the bridge deck of the supporting bridge 7, and the bent part is the pier of the supporting bridge 7, and the supporting bridge 7 plays the role of supporting the heat sensitive layer 8 In addition, it also plays the role of protecting the heat-sensitive layer 8 and absorbing electromagnetic radiation.

In some embodiments, the heat-sensitive layer 8 has a thickness of 30nm-100nm vanadium oxide heat-sensitive thin film layer, while in other embodiments, the heat-sensitive layer 8 can also be a layer of other heat-sensitive thin film materials.

Further, continuing to refer to FIG. 1 , in this embodiment, the substrate 1 is a semiconductor substrate with a built-in readout circuit. The first region on the surface of the semiconductor substrate 1 has a metal electrode layer 2 electrically connected to the readout circuit. The first region is arranged at the edge of the surface of the semiconductor substrate 1 in order to maximize the area of the second region where the getter layer 4 is located. The thickness of the metal electrode layer 2 is 50nm-400nm, and the metal electrode layer 2 includes one of aluminum layer or copper layer. In other embodiments, the substrate 1 can also be other supporting substrates, so that the MEMS process can be formed thereon. After the MEMS process is completed, the other supporting substrates can be removed, and then the electrodes of the microbolometer can be drawn out to the readout circuit. The electrodes of the chip are connected.

In some embodiments, in order to prevent the metal electrode layer 2 from being damaged during the subsequent formation of the getter layer 4, the microbolometer further includes a first dielectric layer 3 on the semiconductor substrate 1, the first Part of the dielectric layer 3 is disposed on the part of the surface of the semiconductor substrate 1 between the metal electrode layer 2 and the getter layer 4 to isolate the metal electrode layer 2 from the getter layer 4 . The piers of the supporting bridge 7 connect the bridge surface of the supporting bridge 7 with the metal electrode layer 2 . That is, the positions of the piers of the supporting bridge 7 are set corresponding to the positions of the metal electrode layer 2 . In some embodiments, the first dielectric layer 3 is an insulating dielectric layer with a thickness of 10 nm-100 nm, and the insulating dielectric layer is a thin film layer such as silicon nitride or silicon dioxide.

The getter layer 4 and the metal electrode layer 2 are located on the same surface of the semiconductor substrate 1 , and the metal electrode layer 2 is located on the periphery of the getter layer 4 . That is, the metal electrode layer 2 is located on the first area of the surface of the semiconductor substrate 1, the getter layer 4 may be located on the second area of the surface of the semiconductor substrate 1, and the first area is located on the periphery of the second area, To maximize the ratio S1/S2 between the area of the getter layer 4 and the area of each pixel structure occupying the surface of the semiconductor substrate 1 . As shown in Figure 2, it is a top view schematic diagram of the getter layer 4 and the semiconductor substrate 1 in Figure 1, wherein, S1 is the area of the getter layer 4, and S2 is the area of each of the above-mentioned pixel structures occupying the semiconductor substrate 1. The area of the surface of the substrate 1. In order to improve the gettering capacity of the getter layer 4 as much as possible, it is necessary to make S1/S2 greater than the preset value. The position and shape of the getter layer 4 and the metal electrode layer 2 on the surface of the semiconductor substrate 1 can be maximized through a reasonable layout. The shape of the getter layer 4 can be square, rectangular or polygonal, or other non-geometric shapes. For example, another shape setting of the getter layer 4 is shown in FIG. 3 .

Continuing to refer to FIG. 1, the microbolometer also includes a second dielectric layer 9 on the support bridge 7, a metal connection layer 10 on the second dielectric layer 9, and a metal connection layer on the second dielectric layer 9. The passivation layer 11 on the dielectric layer 9 and the metal connection layer 10 . Wherein, the second dielectric layer 10 exposes the metal electrode layer 2 and the heat-sensitive layer 8, so that the metal connection layer 10 connects the metal electrode layer 2 and the heat-sensitive layer 8 to form an electrical path to complete the reading process. The output circuit reads the thermal signal generated by the thermal sensitive layer. In some embodiments, the area of the thermally sensitive layer 8 is slightly smaller than the area of the getter layer 4 below it. Wherein, the second dielectric layer 9 conforms to the supporting bridge 7 , that is, the second dielectric layer 9 includes a first portion extending along the deck of the supporting bridge 7 and a second portion extending along the pier of the supporting bridge 7 . A part of the metal connection layer 10 extends on the first part of the second dielectric layer 9 to be electrically connected to the exposed heat-sensitive layer of the second dielectric layer 9, and another part extends from the first part of the second dielectric layer 9 to the second part of the second dielectric layer 9 , and continue to extend above the metal electrode layer 2 exposed by the second dielectric layer, so as to be electrically connected to the metal electrode layer 2 . In some embodiments, the thickness of the metal electrode layer 2 is 50nm-400nm, and the metal electrode layer 2 includes one of an aluminum layer, a copper layer, a titanium layer and a platinum layer. In other embodiments, the constituent material of the metal electrode layer 2 may also be other metal materials with good electrical conductivity.

In some embodiments, the second dielectric layer 9 is a low-stress film layer with a thickness of 10 nm-100 nm, such as silicon oxide, silicon nitride, and other silicon-based layers.

In some embodiments, the thickness of the metal connection layer 10 is 5nm-50nm, and the metal connection layer is a metal layer with good electrical conductivity and low thermal conductivity, for example, it includes at least one of titanium and vanadium .

In some embodiments, the passivation layer 11 is a thin film layer with a thickness of 10 nm-150 nm, such as silicon oxide, silicon nitride, and other silicon-based layers.

In some embodiments, since the getter layer is integrated inside the microbolometer. Therefore, the package structure of the microbolometer provided in the present application is not limited, for example, the package structure is one of a metal package package structure, a ceramic package package structure, a wafer-level package structure and a pixel-level package structure.

Further, the microbolometer shown in FIG. 1 also has a release channel 12 disposed in the stack around the heat-sensitive layer 8, for releasing the sacrificial layer ( removed after microbolometer preparation). Wherein, the stacked layers around the thermal sensitive layer 8 include the bridge surface of the supporting bridge 7 , the second dielectric layer 9 , the metal connection layer 10 and the passivation layer 11 .

In the microbolometer provided in this application, the getter layer 4 adopts a getter with low activation temperature and high getter efficiency, such as but not limited to a Zr-Co-RE thin film getter layer. In some embodiments, the main material of the getter layer 4 is titanium, zirconium, vanadium, chromium, cobalt, iron, manganese, palladium, barium, aluminum, or a multi-phase alloy composed of these materials and rare metals. Due to the large active specific surface area of the thin film getter layer, the main body of the thin film getter layer is easily saturated, adsorbed or oxidized when exposed to air or oxidizing gases, especially when the sacrificial layer is released during the formation of the microbolometer , the thin-film getter layer is easily oxidized by the plasma with higher activity, which will reduce the getter performance of the getter layer 4 or even lose the getter ability. In addition, during the activation process of the microbolometer, the semiconductor substrate 1 will also outgas and diffuse into the getter layer 4, which may cause "poisoning" of the getter.

Therefore, in some embodiments, the microbolometer further includes a getter seed layer between the surface of the semiconductor substrate 1 (or other substrate surface) and the getter layer 4 (Fig. 1), that is, the getter layer 4 is in contact with the surface of the semiconductor substrate 1 through the getter seed layer. The getter seed layer is used to prevent poisoning of the getter layer 4 and improve the adhesion between the getter layer 4 and the surface of the semiconductor substrate 1 .

And, continue to refer to shown in Fig. 1, in the microbolometer that the present application provides, also further comprise the getter protection layer 5 that is positioned at the getter layer 4 surface, to take protective measure to film getter layer 4 , to protect the getter layer 4 from oxidation.

In addition, in order to further improve the detection performance of the microbolometer, it is necessary to reflect the electromagnetic radiation transmitted by the heat-sensitive layer 8, so in the microbolometer provided by the application, the getter layer 5 is also set The electromagnetic radiation reflective layer is used to reflect the electromagnetic radiation transmitted by the heat-sensitive layer 8 back into the heat-sensitive layer 8 for secondary absorption by the heat-sensitive layer 8 .

Specifically, in this embodiment, the getter protective layer 5 and the thermally sensitive layer 8 constitute an optical resonant cavity, therefore, the distance between the getter protective layer 5 and the thermally sensitive layer 8 is The microbolometer described above detects 1/4 the wavelength of electromagnetic radiation. The getter protective layer 5 is a metal layer with a thickness of 5nm-100nm, and the metal layer includes at least one of platinum, gold, silver, nickel, chromium and aluminum. But it should be noted that, in other embodiments, the getter protective layer 5 is not limited to metal layers such as platinum, gold, silver, nickel, chromium, and aluminum, and can also be the detection electromagnetic radiation of the microbolometer. The reflectivity of electromagnetic radiation in the wavelength range is greater than 90% of other metal protective layers.

Therefore, in the present application, the getter protective layer 5 has two functions, the first function is to improve the oxidation of the getter layer, and the second function is to act as a reflective layer to ensure the microbolometer Detection accuracy. The invention simplifies the design and type selection of the getter layer in the structural packaging design process of the microbolometer, effectively reduces the size of the entire microbolometer, simplifies its process, and improves the reliability of the product sex.

The present application also provides a microbolometer with a two-layer bridge structure as a supporting bridge, as shown in Fig. 6c. Different from the microbolometer shown in FIG. 1 , in this embodiment, the support bridge is a multi-layer support bridge.

Please refer to FIG. 6c, the microbolometer includes: a semiconductor substrate 21 with a readout circuit, the first region of the surface of the semiconductor substrate 21 has a metal electrode layer 22, and the surface of the second region has a getter layer 24, wherein the metal electrode layer 22 and the getter layer 24 are separated by the first dielectric layer 23, and the supporting bridge includes the topmost bridge 271 on the surface of the semiconductor substrate 21 and the bridge surface on the bottommost bridge The upper bridge (topmost bridge) 272, the pier of the lowest bridge 271 is located at the position of the metal electrode layer 22, and the getter layer 24 has a getter protective layer 25. A metal connection layer is arranged along the pier and the bridge deck of each layer of the supporting bridge, wherein the metal connection layer includes the bottom metal connection layer 291 arranged along the pier and the bridge deck of the bottom bridge 271 and the pier along the top bridge 272 and the topmost metal connection layer 292 provided on the bridge deck. There is a passivation layer for protecting the metal connection layer on the metal connection layer, and the passivation layer includes the bottom passivation layer 2101 on the bottom metal connection layer 291, the top metal connection layer 292 and the heat sensitive layer 28 on top passivation layer 2102. The heat sensitive layer 28 is located on the topmost bridge 272 and is in contact with the topmost metal connection layer 292 . The stack around the heat sensitive layer 28 has a release channel 212 that penetrates the topmost passivation layer 2102 , the topmost metal connection layer 292 and the bridge surface of the topmost bridge 272 .

Since the getter layer 24 and the getter protective layer 25 in this embodiment are the same as those in FIG. 1 , they will not be repeated in this embodiment.

In addition, as shown in FIG. 4 , it is a schematic flowchart of the preparation method of the microbolometer provided in some embodiments of the present application. The present application also provides a preparation method of a microbolometer, which includes:

S1: Depositing a getter layer on a substrate.

Specifically, in one embodiment, the base is a semiconductor substrate with a built-in readout circuit, the first region of the surface of the semiconductor substrate has a metal electrode layer electrically connected to the readout circuit, the A getter layer is deposited on a second region of the surface of the semiconductor substrate, the first region being located on the periphery of the second region. In other embodiments, the substrate can also be other supporting substrates, so that the MEMS process can be formed thereon. After the MEMS process is completed, the other supporting substrates can be removed, and then the electrodes of the microbolometer and the readout circuit chip Electrode connection. In this embodiment, S1 specifically includes:

S11: Forming a patterned first dielectric layer on the surface of the semiconductor substrate, the first dielectric layer covers the metal electrode layer and exposes a second region of the semiconductor substrate, the metal electrode layer is located on the outside the second area.

S12: Deposit a getter layer on a second region of the surface of the semiconductor substrate exposed by the first dielectric layer.

The thickness of the getter layer is 200nm-1000nm, and the getter layer adopts a getter with low activation temperature and high gettering efficiency, such as but not limited to a Zr-Co-RE thin film getter layer. In some embodiments, the main material of the getter layer is titanium, zirconium, vanadium, chromium, cobalt, iron, manganese, palladium, barium, aluminum, or a multi-phase alloy composed of these materials and rare metals.

In some embodiments, before performing S11, S1 further includes S101 and S102.

S101: Depositing a first metal material layer on the surface of the semiconductor substrate provided with a readout circuit inside.

The material of the first metal layer is generally selected from conductive materials such as aluminum and copper, and its thickness is 50nm-400nm.

S102: Etching the first metal material layer to form a metal electrode layer located in the first region on the surface of the semiconductor substrate and electrically connected to the readout circuit, the metal electrode layer exposing the surface of the semiconductor substrate The second area of , the first area is located around the second area.

Then in S1, the first dielectric layer covers the metal electrode layer and exposes at least part of the second region. Therefore, S12 specifically includes S121 and S122.

S121: Depositing a getter material layer on the surface of the semiconductor substrate by using one of a physical vapor deposition process, a magnetron sputtering process, and an evaporation process;

S122: Pattern the getter material layer by using a Lift-Off process or a photolithography process, so as to form a getter layer located in the second region.

S2: Form a support bridge on the base, the support bridge is a single-layer or multi-layer bridge, each bridge includes piers and a bridge deck, the piers of the bottom bridge are located on the surface of the base, and the bottom bridge The bridge deck is located above the getter layer, and between two adjacent bridges, the pier of the upper bridge is located above the bridge deck of the lower bridge.

S3: Depositing a thermally sensitive layer on the bridge surface of the topmost bridge.

In some embodiments, after forming the support layer, the microbolometer further includes S4.

S4: Form a metal connection layer arranged along the pier and bridge deck of each bridge of the supporting bridge, the metal connecting layer is in contact with the heat-sensitive layer on the topmost bridge surface, and is formed along the supporting bridge extending to the metal electrode layer and contacting the metal electrode layer.

In some embodiments, the microbolometer is a single layer supported bridge structure, S2 comprising:

S21a: forming a sacrificial layer covering the getter layer and having a supporting connection channel on the surface of the semiconductor substrate, where the supporting connecting channel exposes the position where the metal electrode layer is located.

S22a: Deposit an insulating material capable of absorbing electromagnetic radiation on the surface of the sacrifice layer and in the support connection channel to form a single-layer support bridge.

Specifically, in some embodiments, a sacrificial material layer covering the getter layer and the metal electrode layer is formed on the surface of the semiconductor substrate by (spin-coating) deposition and curing processes, and the sacrificial material layer is It is an organic material layer with a thickness of 800nm-2500nm, such as an organic material layer such as polyimide. Then the sacrificial material layer is etched to form a sacrificial layer 6 covering the getter layer and having a supporting connection channel, and the supporting connecting channel is opposite to the metal electrode layer.

A support bridge that can absorb electromagnetic radiation is deposited on the surface of the sacrificial layer and in the support connection channel by using a plasma-enhanced chemical vapor deposition process, and the support bridge conforms to the surface of the sacrificial layer, that is, the support bridge A bridge deck extends over the surface of the sacrificial layer (opposite the absorbing layer), and the piers of the support bridges are located in the support connection channels and are conformal to the side walls of the support connection channels. One end of the pier of the supporting bridge is connected to the metal electrode layer, and the other end is connected to the deck of the supporting bridge. Specifically, one end of the support bridge is connected to the metal electrode layer through the first dielectric layer

Among microbolometers for single-layer support bridges, the S4 includes:

S41a: After the heat-sensitive layer is formed on the bridge deck of the single-layer support bridge, a second medium layer is formed on the pier, the bridge deck, and the heat-sensitive layer of the single-layer support bridge, and the second medium layer The exposed part of the layer is where the heat-sensitive layer and the metal electrode layer are located.

S42a: Form a metal connection layer on the surface of the second dielectric layer, a part of the metal connection layer is located on the bridge surface of the single-layer support bridge and is in contact with the heat-sensitive layer, and the other part of the metal connection layer is along the The pier of the single-layer support bridge extends to the metal electrode layer and contacts the metal electrode layer.

Further, S41a includes:

S411a: depositing a dielectric film material layer composed of silicon nitride and/or silicon dioxide on the pier, the bridge surface and the heat-sensitive layer of the single-layer support bridge.

S412a: Etching away the bottom of the pier of the single-layer support bridge and the dielectric film material layer composed of silicon nitride and/or silicon oxide on part of the thermal sensitive layer, to form a patterned second dielectric layer.

Further, S42a includes:

S421a: Form a second metal material layer on the second dielectric layer by using a physical or chemical vapor deposition process.

S422a: Etching the second metal material layer to form a metal connection layer with one end connected to the heat sensitive layer and the other end connected to the metal electrode layer.

In some embodiments, as shown in FIG. 5 , the manufacturing method of the microbolometer further includes S9, S10, S11 and S12 after completing S8.

S9: forming a patterned second dielectric layer on the supporting bridge and the thermal sensitive layer, the second dielectric layer exposing the metal electrode layer and the thermal sensitive layer.

In some embodiments, S41a includes: first depositing a dielectric film material layer of silicon nitride or silicon dioxide or a combination of both on the support bridge and the thermal sensitive layer, and then etching away the bottom of the support connection channel and part of the material layer on the thermal sensitive layer to form a patterned second dielectric layer. During the patterning of the second dielectric layer, the first dielectric layer on the metal electrode layer will be etched away, so the metal electrode layer is exposed by the patterned second dielectric layer.

In some embodiments, S42a includes forming a second metal material layer on the third thin film layer by using a physical or chemical vapor deposition process, and then etching the second metal material layer to form one end connected to the heat sensitive layer, The other end is connected to the metal connection layer with the metal electrode layer.

The second dielectric layer formed in S41a conforms to the supporting bridge, that is, the second dielectric layer includes a first portion extending along the deck of the supporting bridge, and a second portion extending along the pier of the supporting bridge. A part of the metal connection layer formed in S42a extends on the first part of the second dielectric layer to be electrically connected to the heat-sensitive layer exposed by the second dielectric layer, and another part extends from the first part of the second dielectric layer to the second portion of the second dielectric layer, and continue to extend above the metal electrode layer exposed by the second dielectric layer, so as to be electrically connected to the metal electrode layer. In some embodiments, the thickness of the metal electrode layer is 50nm-400nm, and the metal electrode layer includes one of an aluminum layer, a copper layer, a titanium layer and a platinum layer. In other embodiments, the constituent material of the metal electrode layer may also be other metal materials with good electrical conductivity.

Further, after completing S42a, the microbolometer also includes:

S5a: forming a passivation layer on the second dielectric layer and the metal connection layer.

Specifically, a dielectric thin film of silicon nitride or silicon dioxide or a combination thereof is deposited as a passivation layer on the second dielectric layer and the metal connection layer by plasma enhanced chemical vapor deposition.

Further, after completing S5a, the microbolometer also includes:

S6a: Etch the stack around the thermal sensitive layer to form a release channel for exposing the sacrificial layer in the stack, the stack includes the support bridge, the second dielectric layer, the The above metal connection layer and passivation layer.

Further, after completing S6a, the microbolometer also includes:

S7a: Encapsulating the microbolometer in a housing by using one of a metal package packaging process, a ceramic package package process, a wafer-level packaging process, and a pixel-level packaging process.

In some embodiments, S3 includes: using an ion beam deposition process or a physical vapor deposition process to deposit a heat-sensitive material layer on the bridge surface of the topmost bridge of the support bridge, using an ion beam etching process or a reactive ion etching process Patterning the thermally sensitive material layer to form a thermally sensitive layer located on the bridge surface of the topmost bridge of the supporting bridges and opposite to the getter layer.

In some embodiments, after completing S1 and before performing S2, the preparation method further includes S012.

S012: Form a getter protection layer opposite to the substrate on the getter layer, the getter protection layer is used to protect the getter layer from oxidation.

Specifically, in some embodiments, the getter protective layer is also used to reflect the energy of the electromagnetic radiation transmitted from the heat-sensitive layer to the heat-sensitive layer so as to be absorbed by the heat-sensitive layer, That is, the getter protection layer and the heat-sensitive layer form an optical resonant cavity. Thus, in some embodiments, the distance between the getter protective layer and the thermally sensitive layer is 1/4 of the wavelength of the detected electromagnetic radiation of the microbolometer.

In some embodiments, the getter protection layer is a metal layer with a thickness of 5nm-100nm, and the metal layer includes at least one of platinum, gold, and silver. In other embodiments, the getter The protective layer may also be other metal protective layers whose reflectivity to the electromagnetic radiation in the wavelength range of the detected electromagnetic radiation of the microbolometer is greater than 90%.

In addition, in some embodiments, before forming the getter layer, in order to avoid poisoning of the getter layer and increase the adhesion between the getter layer and the surface of the semiconductor substrate, the micrometer provided by the present application The manufacturing method of the bolometer further includes: depositing and forming a getter seed layer on the second region of the surface of the semiconductor substrate (not shown in FIGS. 1 and 6 c ). The getter layer formed subsequently is made to contact the surface of the semiconductor substrate through the getter seed layer, that is, the getter seed layer is located between the getter layer and the surface of the semiconductor substrate.

In some embodiments, the support bridge of the microbolometer is a multi-layer support bridge, then S2 includes:

S21b: Form at least two layers of sacrificial layers sequentially on the surface of the semiconductor substrate, each sacrificial layer has a support connection channel, the sacrificial layer at the bottom layer covers the getter layer and the support of the sacrificial layer at the bottom layer The connection channel exposes the position where the metal electrode layer is located.

S22b: Depositing an insulating material capable of absorbing electromagnetic radiation on the surface of each layer of the sacrificial layer and in the corresponding supporting connection channel to form each layer of the multi-layer supporting bridge, and the pier of each layer of bridge is located in the corresponding supporting connecting channel, The bridge deck is located on the sacrificial layer surface of the corresponding layer.

Further, in the microbolometer of the multi-layer support bridge, S4 includes: forming the metal connection layer on the pier and bridge deck surface of each layer of the multi-layer support bridge, the metal connection layer is located at the The bridge deck part of the topmost bridge is in contact with the heat-sensitive layer, and the metal connection layer extends from the bridge deck of the topmost bridge to the metal connection layer along each pier and bridge deck of the multi-layer support bridge in turn. The electrode layer is in contact with the metal electrode layer.

Further, after completing S4, the preparation method also includes:

S5b: forming a passivation layer on the metal connection layer.

S6b: Etching the stacked layer around the thermal sensitive layer to form a release channel in the stacked layer, the stacked layer including the passivation layer, the metal connection layer and the bridge surface of the topmost bridge.

The preparation method of the microbolometer provided by the present application will be specifically described below by taking the preparation methods of the microbolometer of the single-layer support bridge and the microbolometer of the support bridge on both sides as examples.

In order to further clearly describe the preparation method of the microbolometer with a single-layer support bridge provided by the present application, Figures 5a to 5k provide schematic diagrams of the structures formed in each step of the preparation method provided according to an embodiment of the present application, as follows A method of manufacturing a microbolometer according to another embodiment provided by the present application will be described with reference to FIGS. 5a to 5k. In this embodiment, the preparation method specifically includes the following steps:

Step 1a: As shown in FIG. 5a , deposit a metal layer on the semiconductor substrate 1 , the metal layer is generally made of Al, and then etch on the metal layer to form a metal electrode layer 2 . Wherein, the metal electrode layer 2 is electrically connected with the readout circuit on the semiconductor substrate 1, and the thickness of the metal electrode layer 2 is 50nm-400nm.

Step 2a: As shown in FIG. 5b , deposit an insulating dielectric layer 3 (first dielectric layer) on the metal electrode layer 2 , and the insulating dielectric layer 3 plays a role of protecting the metal electrode layer 2 . The material of the insulating medium layer 3 can be thin films such as silicon nitride or silicon dioxide, and the thickness of the insulating medium layer 3 is 10nm-100nm.

Step 3a: As shown in FIG. 5c, a getter material layer is deposited on the semiconductor substrate 1 by using physical vapor deposition (Physical Vapor Deposition, PVD), magnetron sputtering or evaporation, and then using the Lift-Off process or The getter layer 4 is formed after the photolithography process is patterned. Wherein the getter layer 4 is located directly below the microbolometer, and the graphic shape is not limited, and can be square, rectangular or polygonal, etc., as shown in Fig. 2 and Fig. 3 . Through rational setting of the position and shape of the metal electrode layer 2 and the getter layer 4, the ratio of the area S1 of the getter layer 4 to the area S2 of the surface of the semiconductor substrate 1 occupied by the pixel structure is maximized , that is, S1/S2 in Figure 2 is greater than the preset value. Specifically, the getter 4 can be selected from materials such as but not limited to titanium, zirconium, vanadium, chromium, cobalt, iron, manganese, palladium, barium, aluminum, or a multiphase alloy composed of these materials and rare metals; the getter Layer 4 has a thickness of 200nm-1000nm. In addition, step 3 also includes depositing a metal protective layer on the surface of the getter layer 4 and patterning it to form a getter protective layer 5, which is used to ensure that the getter layer 4 is completely covered by the getter protective layer 5, and the getter The material of the aerosol protection layer 5 can be selected but not limited to Pt, Au, Ag and other metals with high reflectivity at the wavelength of the electromagnetic radiation to be detected. The thickness of the getter protection layer 5 is 5nm-100nm.

Step 4a: As shown in Figure 5d, centrifuge (spin coating) deposition and solidification on the insulating dielectric layer 3 and the getter protective layer 5 to form an organic sacrificial layer 6. The organic sacrificial layer 6 can be selected from but not limited to polyimide class of organic materials. In order to ensure good coverage of the metal electrode layer 2 and the getter protective layer 5, the organic sacrificial layer 6 acts as a separation layer between the microbolometer and the getter layer 4, and its thickness is 800nm-2500nm, and This layer is removed after the microbolometer is formed.

Step 5a: As shown in FIG. 5e , the organic sacrificial layer 6 is patterned to form a supporting connection channel T corresponding to the second part of the supporting bridge 7 and the metal electrode layer 2 .

Step 6a: As shown in Figure 5f, use plasma enhanced chemical vapor deposition (Plasma Enhanced Chemical Vapor Deposition, PECVD) to deposit the support bridge 7, the material of the support bridge can be but not limited to films such as silicon oxide and silicon nitride, to protect Heat-sensitive film and the role of absorbing electromagnetic radiation. The thickness of the supporting bridge 7 is 50nm-500nm.

In addition, step 6 also includes depositing a heat-sensitive material layer on the support bridge 7 by means of ion beam deposition (Ion Beam Deposition, IBD) or physical vapor deposition (PVD), and then using ion beam etching (Ion Beam Etching, IBE) or reactive ion etching (Reactive Ion Etching, RIE) method to pattern the thermally sensitive material layer to form the thermally sensitive layer 8, the thickness of the thermally sensitive layer 8 is 30nm-100nm.

Step 7a: As shown in FIG. 5g, deposit a dielectric layer 9 on the heat-sensitive layer 8, which can be but not limited to thin films such as low-stress silicon oxide and silicon nitride. The thickness of the dielectric layer 9 is 10nm-100nm. The dielectric layer 9 and the insulating dielectric layer 3 at the pier position are processed by photolithography or etching, and the photolithography or etching ends at the metal electrode layer 2 electrically connected to the readout circuit, so that the metal electrode layer 2 is The dielectric layer 9 is exposed and exposed.

Step 8a: As shown in FIG. 5h , the dielectric layer 9 is processed by photolithography or etching, so that part of the heat-sensitive layer 8 is exposed.

Step 9a: As shown in FIG. 5i , deposit a metal connection material layer by physical vapor deposition (PVD) process. The metal connection material layer is a titanium vanadium thin film with good electrical conductivity and low thermal conductivity, and the thickness of the metal connection layer 10 is 5nm-50nm. And the metal connection material layer on the heat sensitive layer film 8 is removed by photolithography or etching, so as to form the metal connection layer 10 . One end of the metal connection layer 10 is connected to the heat-sensitive layer 8, and the other end is connected to the metal electrode layer 2 of the readout circuit on the semiconductor substrate 1, so as to form an electrical path, and complete the readout of the temperature-sensitive electrical signal by the readout circuit , the area of the heat-sensitive layer 8 is slightly smaller than the area of the getter layer 4 below; the distance between the heat-sensitive layer 8 and the getter protective layer has a great influence on the secondary absorption effect of electromagnetic radiation, and the design distance is electromagnetic radiation 1/4 of the wavelength can reflect the electromagnetic radiation energy transmitted from above back to the heat-sensitive layer 8 for secondary absorption, increase the absorption of the reflected electromagnetic radiation energy by the heat-sensitive layer 8, and improve the overall absorption efficiency of electromagnetic radiation.

Step 10a: As shown in Figure 5j, a passivation layer 11 is deposited on the upper surface of the metal connection layer 10 by methods such as plasma enhanced chemical vapor deposition (PECVD). The passivation layer 11 can be but not limited to silicon oxide, silicon nitride and other thin films, the thin film mainly plays the role of protecting the heat sensitive layer 8 and the metal connection layer 10, so as to prevent subsequent processes from affecting the heat sensitive layer 8 and the metal connection layer 10. Wherein, the thickness of the passivation layer 11 is 10 nm-150 nm.

Step 11a: As shown in FIG. 5k , pattern the stack formed by the support bridge 7 , the dielectric layer 9 , the metal connection layer 10 and the passivation layer 11 to obtain the release channel 12 of the sacrificial layer.

In order to further clearly describe the preparation method of the microbolometer with multi-layer support bridges provided by the present application, Figures 6a to 6c provide schematic diagrams of partial structures formed in the steps of the preparation method according to another embodiment of the present application, as follows A method for manufacturing a microbolometer according to another embodiment provided by the present application will be described with reference to FIGS. 6 a to 6 c. In this embodiment, the preparation method specifically includes the following steps:

Step 1b: As shown in FIG. 6a , a first dielectric layer 23 is formed on the surface of the semiconductor substrate 21 with the metal electrode layer 22 of the readout circuit, and the region of the getter layer 24 is exposed on the first dielectric layer 23 .

Step 2b: As shown in FIG. 6a , form a getter layer 24 on the exposed surface of the semiconductor substrate 21 of the first dielectric layer 23 , and form a getter layer protective layer 25 on the surface of the getter layer 24 .

Step 3b: As shown in FIG. 6a, form the bottom sacrificial layer 261 covering the getter layer 24 and the getter protective layer 25 on the surface of the semiconductor substrate 21, and form the exposed metal electrode in the bottom sacrificial layer 261 Support connection channel at the location of layer 2.

Step 4b: As shown in FIG. 6a , form the bottom bridge 271 on the surface of the bottom sacrificial layer 261 and its corresponding supporting connection channel.

Step 5b: As shown in FIG. 6a , form a conformal bottommost metal connection layer 291 on the surface of the bottommost bridge 271 .

Step 6b: As shown in FIG. 6a , the bottommost passivation layer 2101 is formed on the surface of the bottommost metal connection layer 291 , and the bottommost passivation layer 2101 exposes part of the bottommost metal connection layer 291 .

Step 7b: As shown in FIG. 6b , form the topmost sacrificial layer 262 on the bottommost sacrificial layer 261 and the bottommost passivation layer 291 , and form an exposed layer in the topmost sacrificial layer 262 that is protected by the bottommost passivation layer. The position where the bottommost metal connection layer 291 of the metallization layer 2101 is exposed supports the connection channel.

Step 8b: As shown in FIG. 6b , form the topmost bridge 272 in the topmost sacrificial layer 262 and the corresponding supporting connection channels.

Step 9b: As shown in FIG. 6b , a conformal topmost metal connection layer 292 is formed on the surface of the topmost bridge 272 .

Step 10b: As shown in FIG. 6b , form a heat-sensitive layer 28 on the bridge surface of the topmost bridge 272 .

Step 11b: As shown in FIG. 6b , form the topmost passivation layer 2102 on the bridge surface of the topmost bridge 272 , the heat-sensitive layer 28 and the topmost metal connection layer 292 .

Step 12b: As shown in FIG. 6b , form a release channel 212 in the stack around the heat-sensitive layer 28 , and the release channel runs through the topmost passivation layer 2102 , the topmost metal connection layer 292 and the topmost bridge 272 bridge deck.

Step 13b: As shown in FIG. 6c , etch away the bottommost sacrificial layer 261 and the topmost sacrificial layer 262 to obtain a microbolometer.

In addition, since in this application, the getter layer is made inside the microbolometer, when the microbolometer is packaged to obtain a detector, it can be realized by using different packaging processes, such as Chip-level packaging process, pixel-level packaging process, metal packaging process or ceramic packaging process, etc. As shown in Fig. 7, taking a microbolometer with a single-layer support bridge structure as an example, the microbolometer structure shown in Fig. Cover the surface of the semiconductor substrate 1 to cover the microbolometer structure shown in 5j, and then form a packaging case 14 on the packaging sacrificial material 13, and the packaging case 14 has a packaging release channel 15 thereon.

It should be noted that, in order to form a vacuum cavity, the preparation method according to the present application further includes removing the sacrificial layer and encapsulating the sacrificial material, the release channel is used as the corresponding release channel when removing the sacrificial layer, and the encapsulating release channel is used as the release channel when removing the encapsulation sacrificial material. Corresponding release channel.

As can be seen from the above, the present invention provides a microbolometer for detecting electromagnetic radiation, in which the preparation process of the getter layer is integrated into the MEMS process steps of the traditional microbolometer. The getter adopts a getter with low activation temperature and high suction efficiency, which can be but not limited to Zr-Co-RE thin film getter, and the main material of the getter is titanium, zirconium, vanadium, chromium, cobalt, iron , manganese, palladium, barium, aluminum, or multi-phase alloys composed of these materials and rare metals. Then, a metal protection layer with low activity and high reflectivity is sputtered on the getter by PVD method, and the material of the metal protection layer may be but not limited to metals such as Au or Pt. also. A getter seed layer is arranged between the getter layer and the surface of the semiconductor substrate to prevent poisoning of the getter layer and improve the adhesion between the getter layer and the substrate. The main function of the metal protective layer is to improve the oxidation of the passivation layer of the getter, reduce the oxidation of the getter in the subsequent release process, and at the same time act as a reflective layer to ensure the detection accuracy of the microbolometer. The reflectivity of the metal protective layer is greater than 90% within the wavelength range to be detected. Therefore, the present invention reduces the size and production cost of the entire detector by optimizing the getter design of the microbolometer, and significantly improves the production efficiency and reliability of the microbolometer.

The above is only a specific implementation of the application, but the scope of protection of the application is not limited thereto. Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the application. All should be covered within the scope of protection of this application. Therefore, the protection scope of the present application should be determined by the protection scope of the claims.

Claims

A kind of microbolometer is characterized in that, comprises:

A support bridge located on a base, the support bridge is a single-layer or multi-layer bridge, each layer of bridges includes piers and bridge decks, the piers of the bottommost bridge are located on the surface of the base, between adjacent two-layer bridges, the upper The piers of the bridge on one level are located above the deck of the bridge on the next level;

a getter layer on the surface of the substrate and below the deck of the bottommost bridge;

Heat-sensitive layer on the deck of the topmost bridge.
The microbolometer according to claim 1, wherein the substrate is a semiconductor substrate with a built-in readout circuit, and the first region on the surface of the semiconductor substrate has a power connection with the readout circuit. The metal electrode layer, the pier of the bottom bridge is located on the metal electrode layer;

The microbolometer also includes a metal connection layer arranged along the pier and the bridge deck of each bridge of the supporting bridge, the metal connection layer is in contact with the heat-sensitive layer on the topmost bridge deck, And extending along the support bridge to the metal electrode layer to contact the metal electrode layer;

The getter layer is located on a second area of the surface of the semiconductor substrate, and the first area is located on the periphery of the second area.
The microbolometer according to claim 2, wherein the microbolometer further comprises:

A first dielectric layer located on the surface of the semiconductor substrate, a part of the first dielectric layer is disposed between the metal electrode layer and the getter layer, so that the metal electrode layer and the getter layer getter layer isolation;

a passivation layer located on the surface of the metal connection layer and the heat-sensitive layer;

A release channel located around the heat sensitive layer, the release channel penetrates the passivation layer, the metal connection layer and the bridge surface of the topmost bridge.
The microbolometer according to claim 2, further comprising a second dielectric layer positioned on the topmost bridge and the heat-sensitive layer;

The part of the metal connection layer disposed along the pier and the bridge deck of the topmost bridge is located on the second dielectric layer, and contacts the heat-sensitive layer through the second dielectric layer.
The microbolometer according to claim 1, wherein the material for making the getter layer comprises at least one of titanium, zirconium, vanadium, chromium, cobalt, iron, manganese, palladium, barium, and aluminum. species; or,

The material for making the getter layer includes a multi-phase alloy composed of at least one of titanium, zirconium, vanadium, chromium, cobalt, iron, manganese, palladium, barium, aluminum and rare metals.
The microbolometer according to claim 2, wherein the microbolometer further comprises:

A getter seed layer positioned between the substrate surface and the getter layer.
The microbolometer according to any one of claims 1 to 6, characterized in that, the microbolometer further comprises a getter protective layer on the getter layer, and the getter The aerosol protection layer is used to protect the getter layer from oxidation;

The pier height of the supporting bridge is greater than the sum of the heights of the getter layer and the getter layer protective layer.
The microbolometer according to claim 7, wherein the getter protective layer and the heat-sensitive layer form an optical resonant cavity, so that the getter protective layer will The energy of the transmitted electromagnetic radiation is reflected to the thermally sensitive layer to be absorbed by the thermally sensitive layer.
The microbolometer according to claim 8, wherein the material of the getter protection layer includes at least one of platinum, gold, silver, nickel, chromium and aluminum.
A preparation method of a microbolometer, characterized in that it comprises:

depositing a getter layer on the substrate;

Form a support bridge on the base, the support bridge is a single-layer or multi-layer bridge, each layer of bridge includes piers and bridge decks, the piers of the bottom bridge are located on the base surface, and the bridge deck of the bottom bridge Located above the getter layer, between two adjacent bridges, the pier of the upper bridge is located above the bridge deck of the lower bridge;

A thermally sensitive layer is deposited on the bridge surface of the topmost bridge.
The preparation method according to claim 10, wherein the substrate is a semiconductor substrate with a built-in readout circuit, and the first region on the surface of the semiconductor substrate has a metal electrode electrically connected to the readout circuit layer, said depositing a getter layer on a substrate, comprising:

A patterned first dielectric layer is formed on the surface of the semiconductor substrate, the first dielectric layer covers the metal electrode layer and exposes a second region of the semiconductor substrate surface, the first region is located on the first The periphery of the second area;

depositing a getter layer on said second region;

Wherein, the material for making the getter layer includes at least one of titanium, zirconium, vanadium, chromium, cobalt, iron, manganese, palladium, barium, and aluminum, or the material for making the getter layer includes titanium, A multi-phase alloy composed of at least one of zirconium, vanadium, chromium, cobalt, iron, manganese, palladium, barium, aluminum and a rare metal;

The preparation method also includes:

Forming a metal connection layer arranged along the pier and the bridge deck of each layer of the supporting bridge, the metal connecting layer is in contact with the heat-sensitive layer on the topmost bridge surface, and extends along the supporting bridge to The metal electrode layer is in contact with the metal electrode layer.
The preparation method according to claim 11, wherein the depositing a getter layer in the second region comprises:

depositing a layer of getter material on said second region using one of a physical vapor deposition process, a magnetron sputtering process, and an evaporation process;

The getter material layer is patterned using a Lift-Off process or a photolithography process to form the getter layer.
The preparation method according to claim 11, wherein, before forming the patterned first dielectric layer on the surface of the semiconductor substrate, depositing a getter layer on the substrate further comprises:

Depositing a first metal material layer on the surface of the semiconductor substrate provided with a readout circuit;

Etching the first metal material layer to form a metal electrode layer located in the first region and electrically connected to the readout circuit, the metal electrode layer exposing the second region.
The preparation method according to claim 11, wherein said forming a support bridge on said substrate comprises:

forming a sacrificial layer covering the getter layer and having a supporting connection channel on the surface of the semiconductor substrate, the supporting connecting channel exposing the position where the metal electrode layer is located;

depositing an insulating material capable of absorbing electromagnetic radiation on the surface of the sacrificial layer and in the supporting connection channel to form a single-layer supporting bridge;

Forming the metal connection layer arranged along the pier and the bridge deck of each layer of the supporting bridge, including:

After the heat-sensitive layer is formed on the bridge deck of the single-layer support bridge, a second dielectric layer is formed on the pier, bridge deck and the heat-sensitive layer of the single-layer support bridge, and the second dielectric layer is exposed The position where part of the heat-sensitive layer and the metal electrode layer are located;

A metal connection layer is formed on the surface of the second dielectric layer, a part of the metal connection layer is located on the bridge surface of the single-layer support bridge and is in contact with the heat-sensitive layer, and the other part of the metal connection layer is along the The pier of the single-layer support bridge extends to the metal electrode layer and contacts the metal electrode layer.
The preparation method according to claim 14, wherein the formation of the second dielectric layer on the pier, the bridge deck and the heat-sensitive layer of the single-layer support bridge comprises:

Depositing a dielectric film material layer composed of silicon nitride and/or silicon dioxide on the pier, bridge deck and the heat-sensitive layer of the single-layer support bridge;

Etching away the bottom of the pier of the single-layer support bridge and the dielectric film material layer composed of silicon nitride and/or silicon oxide on part of the heat-sensitive layer to form a patterned second dielectric layer;

Forming a patterned metal connection layer on the second dielectric layer, comprising:

forming a second metal material layer on the second dielectric layer by using a physical or chemical vapor deposition process;

Etching the second metal material layer to form a metal connection layer with one end connected to the heat sensitive layer and the other end connected to the metal electrode layer.
The preparation method according to claim 11, wherein said forming a support bridge on said substrate comprises:

At least two layers of sacrificial layers are sequentially formed on the surface of the semiconductor substrate, each layer of the sacrificial layer has a support connection channel, the sacrificial layer at the bottom layer covers the getter layer and the support connection of the sacrificial layer at the bottom layer The channel exposes the position where the metal electrode layer is located;

An insulating material capable of absorbing electromagnetic radiation is deposited on the surface of each layer of the sacrificial layer and the corresponding supporting connection channel to form each layer of the multi-layer supporting bridge, and the pier of each layer of bridge is located in the corresponding supporting connecting channel, and the bridge deck The surface of the sacrificial layer located on the corresponding layer;

Forming the metal connection layer arranged along the pier and the bridge deck of each layer of the supporting bridge, including:

The metal connection layer is formed on the pier and bridge deck surface of each layer of the multi-layer support bridge, and the metal connection layer is located at the bridge deck part of the topmost bridge in contact with the heat-sensitive layer. The connection layer extends from the bridge surface of the topmost bridge along each pier and bridge surface of the multi-layer support bridge to the metal electrode layer in contact with the metal electrode layer.
The preparation method according to claim 11, wherein, after forming the metal connection layer arranged along the pier and the bridge deck of each bridge of the supporting bridge, the preparation method also includes:

forming a passivation layer on the metal connection layer;

Etching the stack around the thermally sensitive layer to form a release channel in the stack, the stack including the passivation layer, the metal connection layer, and the bridge deck of the topmost bridge.
The preparation method according to claim 10, wherein, before depositing the getter layer on the substrate, the preparation method further comprises:

forming a getter seed layer on the surface of the substrate;

The depositing a getter layer on the substrate comprises:

A getter layer is deposited on the getter seed layer.
According to the preparation method according to any one of claims 10 to 18, it is characterized in that, after the getter layer is deposited on the surface of the substrate, a getter layer covering the getter layer and having a support is formed on the surface of the substrate. Before connecting the sacrificial layer of the channel, the preparation method also includes:

forming a getter protective layer opposite to the substrate on the getter layer, the getter protective layer is used to protect the getter layer from oxidation;

Wherein, the height of the supporting connection channel is greater than the sum of the thicknesses of the getter layer and the getter protective layer; the getter protective layer and the heat-sensitive layer form an optical resonant cavity, so that the The getter protective layer reflects energy of electromagnetic radiation transmitted from the heat sensitive layer to the heat sensitive layer to be absorbed by the heat sensitive layer.