Detector pixel structure and preparation method thereof

Abstract

The invention provides a detector pixel structure and a preparation method thereof. The detector pixel structure comprises a substrate; the first micro-bridge structure comprises a first pixel pier, a first cantilever beam and a first bridge surface, the first pixel pier is arranged on the surface of the substrate, the first cantilever beam is connected to the first pixel pier, and the first bridge surface is connected to the first cantilever beam; a thermosensitive layer is formed in the first bridge surface; the first cantilever beam comprises a first dielectric layer, a second dielectric layer, an electrode layer and a third dielectric layer which are stacked in sequence, and the width of the first dielectric layer, the width of the second dielectric layer and the width of the third dielectric layer are larger than the width of the electrode layer. According to the technical scheme, the infrared detector pixel structure in which the width of the first cantilever beam electrode layer is smaller than that of the dielectric layer is provided, and the heat insulation performance of the pixel structure can be greatly improved through the thin electrode layer; the wide dielectric layer is adopted, the strength performance of the pixel structure is improved, and the antistatic property and the environmental adaptability of the detector are improved.

Description

Technical Field

[0001] The present invention relates to the field of uncooled infrared detectors, and in particular to a detector pixel structure and a preparation method thereof. Background Art

[0002] Uncooled infrared detectors usually work in a passive sensing mode, with advantages such as long range, good anti-interference, strong ability to penetrate smoke and haze, and all-day operation, and are widely used in aerospace remote sensing, military equipment, astronomical detection, etc. At present, the main development trend is the high-end third-generation infrared photoelectric detectors characterized by ultra-high spatial resolution, ultra-high energy resolution, ultra-high temporal resolution, and ultra-high spectral resolution, which constantly challenge and break through the limits of infrared light intensity detection capabilities.

[0003] To achieve the ultra-high resolution capability of uncooled infrared detectors, it is necessary to improve the noise equivalent temperature difference (NETD) performance of the detector. Since the noise equivalent temperature difference performance is positively correlated with the thermal insulation ability of the infrared detector pixel, how to improve the thermal insulation performance of the pixel structure has always been a problem that researchers have been studying tirelessly. At present, small pixels and large arrays are the main development direction of infrared detectors, but the reduction of pixel size will inevitably lead to a reduction in the design space of the micro-bridge infrared absorption area and the micro-bridge cantilever beam. At the same time, the two are mutually restrictive. Increasing one will inevitably lead to a reduction in the other. Uncooled infrared detectors are widely used in weapons and equipment and vehicle systems. They need to withstand mechanical shock and high and low temperature extreme environments for a long time. Therefore, when designing the pixel structure, the micro-bridge cantilever beam structure cannot be designed to be too thin or too long. Although the slender cantilever beam can improve the thermal insulation performance of the pixel structure, the slender pixel cantilever beam will inevitably reduce the mechanical strength of the structure, and dead spots are prone to occur during the use of the detector. In addition, the slender cantilever beam structure will place higher requirements on the manufacturing and processing of the detector, and it is easy to produce non-uniformity during the lithography and etching process of the pixel array, causing the output of the detector to exceed the dynamic range. In view of the above problems, when designing the pixel structure, it is necessary to comprehensively consider the material properties, structural design and processing flow of the infrared detector pixel.

[0004] The traditional pixel structure is generally processed by etching the electrode layer of the cantilever beam and the upper and lower protective dielectric layers together. The electrode layer of the formed cantilever beam is consistent with the width of the dielectric layer. Since the electrode layer of the pixel is generally made of metal or alloy film, such as titanium (Ti), aluminum (Al), titanium nitride (TiN), nickel-chromium alloy (NiCr), etc., its thermal conductivity is generally large. For example, the thermal conductivity of metal Ti is 22W / (m·k), the thermal conductivity of metal Al is 237W / (m·k), and the thermal conductivity of semiconductor dielectric film silicon nitride and silicon oxide is generally around 2W / (m·k). It can be found that the thermal conductivity of metal materials is ten times or even a hundred times that of dielectric films. The thermal conductivity of the pixel microbridge G = n[(w·t) / L]λ, where n is the number of microcantilever beams, which is generally a fixed value, λ is the thermal conductivity of the microcantilever beam material, w is the width of the microcantilever beam, t is the thickness of the microcantilever beam, and L is the length of the microcantilever beam. It can be seen from the formula that when the electrode material is fixed, the thermal conductivity of the material has also been determined. If you want to reduce the total thermal conductivity G, you can only reduce the width w and thickness t of the cantilever beam, or increase the length L of the cantilever beam. The smaller the thermal conductivity, the more conducive it is to improving the thermal insulation performance of the pixel. Therefore, the pixel cantilever beam adopts a structure in which the electrode layer with large thermal conductivity and the dielectric layer are of the same width, which is not conducive to reducing the thermal conductivity of the pixel microbridge. In addition, since the thermal conductivity of the metal material of the electrode layer is relatively large, a thinner film thickness is generally used in the process to reduce the thermal conductivity. However, the lower film thickness leads to poor film coverage at the pixel bridge pier, especially the side wall of the bridge pier may not be fully covered, resulting in a short circuit. In the actual process, after the electrode film layer is completed, a thick metal layer will be deposited to increase the electrical connection at the bridge pier, but the deposition and etching of the thick metal layer increase the difficulty of the process, and will also affect the consistency of the pixel array processing. Therefore, how to reduce the thermal conductivity of the pixel cantilever beam while simplifying the processing technology of the pixel microbridge has always been a problem for researchers.

[0005] Therefore, how to design a pixel structure with excellent thermal insulation performance, high mechanical strength and easy processing is a problem that needs to be solved at present. Summary of the invention

[0006] The technical problem to be solved by the present invention is how to design a pixel structure with excellent thermal insulation performance, high mechanical strength and easy processing, and to provide a detector pixel structure and a preparation method thereof.

[0007] In order to solve the above problems, the present invention provides a detector pixel structure, including: a substrate; a first microbridge structure, including a first pixel bridge pier, a first cantilever beam, and a first bridge deck, the first pixel bridge pier is arranged on the surface of the substrate, the first cantilever beam is connected to the first pixel bridge pier, and the first bridge deck is connected to the first cantilever beam; a thermal sensitive layer is formed in the first bridge deck; the first cantilever beam includes a first dielectric layer, a second dielectric layer, an electrode layer, and a third dielectric layer stacked in sequence, and the widths of the first dielectric layer, the second dielectric layer, and the third dielectric layer are greater than the width of the electrode layer.

[0008] The above technical solution proposes an infrared detector pixel structure in which the width of the first cantilever beam electrode layer is smaller than the width of the dielectric layer. The thinner electrode layer can greatly improve the thermal insulation performance of the pixel structure. At the same time, a wider dielectric layer is used to improve the strength performance of the pixel structure and improve the anti-static properties and environmental adaptability of the detector.

[0009] It should be understood that the above general description and the detailed description below are exemplary and explanatory only and cannot limit the present invention. The techniques, methods and devices known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, the techniques, methods and devices should be considered as part of the authorization specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the following is a brief introduction to the drawings required for the description of the specific embodiments. Obviously, the drawings described below are only some specific embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0011] Figure 1 It is a side cross-sectional view of the first embodiment of the detector pixel structure of the present invention.

[0012] Figure 2 FIG. 1 is a top view of a second embodiment of the detector pixel structure of the present invention.

[0013] Figure 3 FIG. 4 is a top view of a third embodiment of the detector pixel structure of the present invention.

[0014] Figure 4 It is a side cross-sectional view of a fourth embodiment of the detector pixel structure of the present invention.

[0015] Figure 5 It is a side cross-sectional view of a fifth embodiment of the detector pixel structure of the present invention.

[0016] Figure 6The present invention is a flowchart of the steps of an embodiment of a method for manufacturing a detector pixel structure according to the present invention.

[0017] Figure 7 A schematic structural diagram of a substrate is provided for an embodiment of a method for manufacturing a detector pixel structure of the present invention.

[0018] Figure 8 This is a structural schematic diagram of forming a sacrificial layer on the surface of the substrate in an embodiment of the method for manufacturing the detector pixel structure of the present invention.

[0019] Fig. 9 This is a structural schematic diagram of depositing a first dielectric material layer, a thermal sensitive layer and a second dielectric material layer on the surface of the sacrificial layer in an embodiment of the method for manufacturing the detector pixel structure of the present invention.

[0020] Fig.10 This is a schematic structural diagram of a deposited electrode material layer in an embodiment of a method for manufacturing a detector pixel structure according to the present invention.

[0021] Fig.11 This is a structural schematic diagram of forming a first microbridge structure on the surface of the sacrificial layer in an embodiment of the method for manufacturing the detector pixel structure of the present invention. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0023] In order to solve the problem that improving the insulation performance of small pixels by increasing the length of the microbridge cantilever beam will lead to a reduction in the infrared absorption area of ​​the pixel, thereby affecting the performance of the detector; and at the same time to improve the machinability of the pixel structure, the present invention proposes a pixel structure and a manufacturing method thereof.

[0024] See also Figure 1 , which is a side cross-sectional view of the first embodiment of the detector pixel structure of the present invention. Figure 1As shown, the detector pixel structure includes: a substrate 10 and a first microbridge structure 11. The first microbridge structure 11 includes a first pixel bridge pier 111, a first cantilever beam 112, and a first bridge deck 113, wherein the first pixel bridge pier 111 is arranged on the surface of the substrate 10, the first cantilever beam 112 is connected to the first pixel bridge pier 111, and the first bridge deck 113 is connected to the first cantilever beam 112; a thermosensitive layer 12 is formed in the first bridge deck 113; the first cantilever beam 112 includes a first dielectric layer 13, a second dielectric layer 14, an electrode layer 15, and a third dielectric layer 16 stacked in sequence, wherein the widths of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 are greater than the width of the electrode layer 15.

[0025] The present invention proposes an infrared detector pixel structure in which the width of the first cantilever beam electrode layer is smaller than the width of the dielectric layer. The thinner electrode layer can greatly improve the thermal insulation performance of the pixel structure; at the same time, a wider dielectric layer is used to improve the strength performance of the pixel structure and improve the environmental adaptability of the detector.

[0026] like Figure 1 As shown, the substrate 10 includes a detection readout circuit (ROIC) 101, a reflective layer 102 formed on the surface of the detection readout circuit 101, and a metal connection structure 103 formed on the same layer as the reflective layer 102. The material of the reflective layer 102 can be metal aluminum, metal copper, copper-aluminum alloy, etc.

[0027] In some embodiments, the materials of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 can be semiconductor dielectric films or composite dielectric films such as silicon nitride, silicon oxide, and silicon oxynitride. Since the thermal conductivity of semiconductor dielectric films is low and the Young's modulus is high, a wider first cantilever beam 112 structure can be used to improve the strength performance of the pixel structure and improve the environmental adaptability of the detector. The wrapping method of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 for the electrode layer 15 can be full wrapping or half wrapping.

[0028] In some embodiments, the material of the thermosensitive layer 12 can be a material having a temperature coefficient of resistance, such as vanadium oxide, amorphous silicon, polycrystalline silicon, and titanium oxide; the material of the electrode layer 15 can be metal titanium, titanium nitride, and nickel-chromium alloy.

[0029] Figure 1 In the illustrated embodiment, the first bridge deck 113 and the first cantilever beam 112 are on the same level.

[0030] In some embodiments, the ratio of the width of the electrode layer 15 to the width of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 is in a range of 1:(1, 4]. The ratio of the width of the electrode layer 15 to the width of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 is in a range of 1:(1, 4] includes: the ratio of the width of the electrode layer 15 to the width of the first dielectric layer 13 is in a range of 1:(1, 4], the ratio of the width of the electrode layer 15 to the width of the second dielectric layer 14 is in a range of 1:(1, 4], and the ratio of the width of the electrode layer 15 to the width of the third dielectric layer 16 is in a range of 1:(1, 4]. In this embodiment, the widths of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 are equal and are The widths of the first cantilever beam 112 are equal; the ratio of the width of the electrode layer 15 to the widths of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 is 1:2. In other embodiments, the ratio of the width of the electrode layer 15 to the widths of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 can also be 1:1.2, 1:1.5, 1:3, or 1:4. The thinner electrode layer 15 can greatly improve the thermal insulation performance of the pixel structure; at the same time, the wider first cantilever beam 112 is used to improve the strength performance of the pixel structure and improve the environmental adaptability of the detector. In some embodiments, the width of the electrode layer 15 is less than 500nm, and the widths of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 are less than 1000nm.

[0031] The prior art usually reduces thermal conductivity by thinning the electrode layer 15, but if the electrode layer 15 is too thin, it will affect the coverage of the first pixel bridge pier 111, and further affect the electrical properties of the electrode layer 15. Therefore, the present invention improves the thermal insulation performance by reducing the width of the electrode layer 15, and at the same time appropriately increases the thickness of the electrode layer 15, improves the coverage of the electrode layer 15 film at the first pixel bridge pier 111, eliminates the subsequent thick metal filling process, and improves the electrical connection reliability at the first pixel bridge pier 111, thereby simplifying the processing process of the pixel structure, improving the processing consistency of the pixel array, and improving the output uniformity of the infrared detector.

[0032] In some embodiments, the thickness of the electrode layer 15 ranges from 5 nm to 50 nm. In this embodiment, the thickness of the electrode layer 15 is 30 nm. In other embodiments, the thickness of the electrode layer 15 may also be 5 nm, 10 nm, 20 nm, 40 nm or 50 nm.

[0033] In some embodiments, the first cantilever beam 112 can be designed with one fold, two folds or multiple folds according to different requirements of the thermal insulation performance of the pixel, and its shape can be different shapes such as W-shape and L-shape.

[0034] In this embodiment, the width of the first cantilever beam 112 is kept uniform at all locations.

[0035] See also Figure 2 , which is a top view of the second embodiment of the detector pixel structure of the present invention. Figure 2 The embodiment shown is Figure 1 The difference of the embodiment shown is that the width of the first cantilever beam 112 gradually increases from the side close to the first bridge deck 113 to the side close to the first pixel bridge pier 111. On the side close to the first pixel bridge pier 111, the first cantilever beam 112 has the same width as the first pixel bridge pier 111, so as to enhance the connection strength of the first cantilever beam 112.

[0036] In this embodiment, the width of the electrode layer 15 is kept uniform. In other embodiments, the width of the electrode layer 15 gradually increases from the side close to the first bridge deck 113 to the side close to the first pixel bridge pier 111, and is always smaller than the width of the first cantilever beam 112.

[0037] See also Figure 3 , which is a top view of the third embodiment of the detector pixel structure described in the present invention. Figure 3 The embodiment shown is Figure 1 The difference from the embodiment shown is that the first bridge deck 113 further includes a bridge deck dielectric layer 31, and the width of the bridge deck dielectric layer 31 is greater than the electrode layer 35 of the first bridge deck 113. The bridge deck dielectric layer 31 also wraps the electrode layer 35 of the first bridge deck 113, so that charges cannot be accumulated on the pixel bridge legs and the bridge deck surface, avoiding the problem of deformation or collapse of the pixel microbridge caused by electrostatic adsorption between the pixel and the substrate, and can play a good anti-static role during the use of the detector.

[0038] See also Figure 4 , which is a side sectional view of the fourth embodiment of the detector pixel structure of the present invention. Figure 4 The embodiment shown is Figure 1 What is different from the illustrated embodiment is that the detector pixel structure further includes a second microbridge structure 42 , and the second microbridge structure 42 includes a second pixel bridge pier 421 located above the first bridge deck 113 and a second absorption layer 422 located on both sides of the second pixel bridge pier 421 .

[0039] In some embodiments, the second micro-bridge structure 42 is a semiconductor film or a metal film, and is used to increase the infrared absorption area of ​​the detector pixel structure.

[0040] See also Figure 5 , which is a side sectional view of the fifth embodiment of the detector pixel structure of the present invention. Figure 5 The embodiment shown is Figure 1 The difference from the embodiment shown is that the first bridge deck 113 is located above the first cantilever beam 112, and the first bridge deck 113 is connected to the first cantilever beam 112 through the third pixel bridge pier 53. The first bridge deck 113 and the first cantilever beam 112 are arranged in layers, which can optimize the spatial layout and is conducive to improving the performance of the small-size pixel structure.

[0041] In some embodiments, the first bridge deck 113 includes a fourth dielectric layer 51 and a thermal sensitive layer 52 .

[0042] In some embodiments, a conductive column 531 is disposed in the third pixel bridge pier 53 , and the conductive column 531 is electrically connected to the thermal sensitive layer 52 and the electrode layer 15 . The third pixel bridge pier 53 further includes a fifth dielectric layer 532 .

[0043] In this embodiment, the first cantilever beam 112 is on the first floor, and the first bridge deck 113 is on the second floor. In other embodiments, a double-layer structure may be added. Figure 4 The second micro-bridge structure 42 shown may also adopt a multi-layer structure of a double-layer cantilever beam and a double-layer bridge deck.

[0044] Based on the same inventive concept, an embodiment of the present invention further provides a method for manufacturing a detector pixel structure.

[0045] See also Figure 6 , which is a flowchart of the steps of an embodiment of the method for manufacturing the detector pixel structure of the present invention. Figure 6 As shown, the method for manufacturing the detector pixel structure includes the following steps: step S61, providing a substrate; step S62, forming a sacrificial layer on the surface of the substrate, the sacrificial layer having a first hole, and the bottom of the first hole exposing the substrate; step S63, forming a first microbridge structure on the surface of the sacrificial layer, the first microbridge structure including a first pixel pier, a first cantilever beam and a first bridge deck, the first pixel pier is arranged on the surface of the substrate, the first cantilever arm is connected to the first pixel pier, the first bridge deck is connected to the first cantilever beam, a thermal sensitive layer is formed in the first bridge deck, the first cantilever arm includes a first dielectric layer, a second dielectric layer, an electrode layer, and a third dielectric layer stacked in sequence, and the width of the electrode layer is less than a preset threshold; step S64, removing the sacrificial layer.

[0046] See also Figure 7 And step S61, providing a substrate 10. The substrate 10 includes a detection readout circuit (ROIC) 101 made by CMOS process, a reflective layer 102 formed on the surface of the detection readout circuit 101, and a metal connection structure 103 formed on the same layer as the reflective layer 102. The material of the reflective layer 102 can be metal aluminum, metal copper, copper-aluminum alloy, etc.

[0047] See also Figure 8 And step S62, forming a sacrificial layer 80 on the surface of the substrate 10, the sacrificial layer 80 having a first hole 801, the bottom of the first hole 801 exposing the substrate 10. In some embodiments, the material of the sacrificial layer 80 can be polyimide (PI), polysilicon, amorphous silicon, silicon dioxide, etc., and the thickness is 1 / 4 of the target detection wavelength.

[0048] See also Fig.11 And step S63, forming a first microbridge structure 11 on the surface of the sacrificial layer 80, the first microbridge structure 11 includes a first pixel pier 111, a first cantilever beam 112 and a first bridge deck 113, the first pixel pier 111 is arranged on the surface of the substrate 10, the first cantilever beam 112 is connected to the first pixel pier 111, the first bridge deck 113 is connected to the first cantilever beam 112, a thermosensitive layer 12 is formed in the first bridge deck 113, the first cantilever beam 112 includes a first dielectric layer 13, a second dielectric layer 14, an electrode layer 15, and a third dielectric layer 16 stacked in sequence, the width of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 is greater than the width of the electrode layer 15.

[0049] Figures 9 to 11 An embodiment of forming a first microbridge structure 11 on the surface of the sacrificial layer 80 is shown to form Figure 1 The structure shown. Figures 9 to 11 As shown, in this embodiment, forming the first microbridge structure 11 on the surface of the sacrificial layer 80 further includes the following steps:

[0050] like Fig. 9As shown, a first dielectric material layer 930, a thermosensitive layer 12, and a second dielectric material layer 940 are deposited on the surface of the sacrificial layer 80; the first dielectric material layer 930 and the second dielectric material layer 940 are etched to form a second hole 902 at the bottom of the first hole 801, and a third hole 903 is formed in the second dielectric material layer 940 on the surface of the thermosensitive layer 12, the bottom of the second hole 902 exposes the substrate 10, and the bottom of the third hole 903 exposes the thermosensitive layer 12. In some embodiments, the material of the thermosensitive layer 12 can be a material having a temperature coefficient of resistance, such as vanadium oxide, amorphous silicon, polycrystalline silicon, and titanium oxide.

[0051] In some embodiments, the materials of the first dielectric layer 13 and the second dielectric layer 14 may be semiconductor dielectric films or composite dielectric films such as silicon nitride, silicon oxide, and silicon oxynitride. Since the semiconductor dielectric film has low thermal conductivity and high Young's modulus, a wider first cantilever beam 112 structure may be used to improve the strength performance of the pixel structure and enhance the environmental adaptability of the detector.

[0052] like Fig.10 As shown, an electrode material layer is deposited on the surface of the second dielectric material layer 940, the second hole 902 and the third hole 903; the electrode material layer is patterned to form an electrode layer 15, and the width of the electrode layer 15 is less than a preset threshold. In some embodiments, the material of the electrode layer 15 can be metal titanium, titanium nitride, nickel-chromium alloy, etc.; the width of the electrode layer 15 is less than 500nm.

[0053] The prior art usually reduces thermal conductivity by thinning the electrode layer 15, but if the electrode layer 15 is too thin, it will affect the coverage of the first pixel bridge pier 111, and further affect the electrical properties of the electrode layer 15. Therefore, the present invention improves the thermal insulation performance by reducing the width of the electrode layer 15, and at the same time appropriately increases the thickness of the electrode layer 15, improves the coverage of the electrode layer 15 film at the first pixel bridge pier 111, eliminates the subsequent thick metal filling process, and improves the electrical connection reliability at the first pixel bridge pier 111, thereby simplifying the processing process of the pixel structure, improving the processing consistency of the pixel array, and improving the output uniformity of the infrared detector.

[0054] In some embodiments, the thickness of the electrode layer 15 ranges from 5 nm to 50 nm. In this embodiment, the thickness of the electrode layer 15 is 30 nm. In other embodiments, the thickness of the electrode layer 15 may also be 5 nm, 10 nm, 20 nm, 40 nm or 50 nm.

[0055] like Fig.11As shown, a third dielectric material layer is deposited to form the first pixel bridge pier 111 in the first hole 801, and the first bridge deck 113 is formed at the thermal sensitive layer 12; the third dielectric material layer, the second dielectric material layer 940, and the first dielectric material layer 930 are patterned to form a first dielectric layer 13, a second dielectric layer 14, and a third dielectric layer 16, and the widths of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 are greater than the width of the electrode layer 15, and the first cantilever beam 112 connecting the first pixel bridge pier 111 and the first bridge deck 113 is formed.

[0056] In some embodiments, the material of the third dielectric layer 16 may be a semiconductor dielectric film or a composite dielectric film such as silicon nitride, silicon oxide, and silicon oxynitride. The wrapping method of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 for the electrode layer 15 may be full wrapping or half wrapping. In some embodiments, the first cantilever beam 112 may be designed with one fold, two folds, or multiple folds according to different requirements of the thermal insulation performance of the pixel, and its shape may be different shapes such as W-shaped and L-shaped.

[0057] In this embodiment, the first bridge deck 113 and the first cantilever beam 112 are on the same level.

[0058] In some embodiments, the ratio of the width of the electrode layer 15 to the width of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 is in the range of 1:(1,4). In this embodiment, the ratio of the width of the electrode layer 15 to the width of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 is 1:2. Specifically, the width of the electrode layer 15 is 200nm, and the width of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 is 400nm. In other embodiments, the electrode layer 1 The ratio of the width of the electrode layer 15 to the width of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 can also be 1:1.2, 1:1.5, 1:3, or 1:4. The thinner electrode layer 15 can greatly improve the thermal insulation performance of the pixel structure; at the same time, the wider first cantilever beam 112 is used to improve the strength performance of the pixel structure and improve the environmental adaptability of the detector. In some embodiments, the width of the electrode layer 15 is less than 500nm, and the width of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 is less than 1000nm.

[0059] In order to further increase the infrared absorption area of ​​the pixel structure, an absorption umbrella structure can be made on the basis of a single-layer microbridge, and the absorption umbrella can be made of a semiconductor dielectric film or a metal film combination. Fig.11The process steps are continued on the basis shown to form Figure 4 In this embodiment, after the step of forming the first microbridge structure 11 on the surface of the sacrificial layer 80, the following step is also included: forming a second microbridge structure 42 above the first microbridge structure 11, the second microbridge structure 42 includes a second pixel bridge pier 421 located above the first bridge deck 113 and a second absorption layer 422 located on both sides of the second pixel bridge pier 421. In some embodiments, the second microbridge structure 42 is a semiconductor film or a metal film, which is used to increase the infrared absorption area of ​​the detector pixel structure.

[0060] With the development of technology, the size of the non-cooled infrared pixel structure is getting smaller and smaller. The cantilever beam and the thermosensitive material of the pixel structure are made in the same layer, which is increasingly limited by the pixel size, which is not conducive to the improvement of the structural performance. Therefore, the present invention also provides another embodiment of forming the first microbridge structure 11 on the surface of the sacrificial layer 80, which separates the cantilever beam and the thermosensitive material to form Figure 5 The structure shown.

[0061] In this embodiment, forming the first microbridge structure 11 on the surface of the sacrificial layer 80 further includes the following steps: (1) depositing a first dielectric material layer, a second dielectric material layer, and an electrode material layer on the surface of the sacrificial layer 80 in sequence; (2) patterning the electrode material layer to form an electrode layer 15, wherein the width of the electrode layer 15 is less than a preset threshold; (3) depositing a third dielectric material layer to form the first pixel bridge pier 111 in the first hole 801; (4) patterning the third dielectric material layer, the second dielectric material layer, and the first dielectric material layer; (5) forming a first dielectric layer 13, a second dielectric layer 14, and a third dielectric layer 16, wherein the width of the first dielectric layer 13, the second dielectric layer 14, and the third dielectric layer 16 is greater than the width of the electrode layer 15, and forming the first cantilever beam 112 connected to the first pixel bridge pier 111; (5) forming a third pixel bridge pier 53 and a first bridge deck 113 in sequence above the first cantilever beam 112, wherein a thermal sensitive layer 12 is formed in the first bridge deck 113, and is connected to the first cantilever beam 112 through the third pixel bridge pier 53.

[0062] In some embodiments, the first bridge deck 113 includes a fourth dielectric layer 51 and a thermal sensitive layer 52 .

[0063] In some embodiments, a conductive column 531 is disposed in the third pixel bridge pier 53 , and the conductive column is electrically connected to the thermal sensitive layer 52 and the electrode layer 15 .

[0064] In this embodiment, the first cantilever beam 112 is on the first floor, and the first bridge deck 113 is on the second floor. In other embodiments, a double-layer structure may be added. Figure 4 The second micro-bridge structure 42 shown may also adopt a multi-layer structure of a double-layer cantilever beam and a double-layer bridge deck.

[0065] See also Figure 1 And step S64, removing the sacrificial layer 80. After removing the sacrificial layer 80, a suspended first microbridge structure 11 is obtained.

[0066] The present invention proposes an infrared detector pixel structure for etching the electrode layer of the first cantilever beam separately, firstly etching the electrode layer of the first cantilever beam into a thinner connection structure, then depositing a semiconductor dielectric film and etching a wider first cantilever beam structure, forming a dielectric film at the first cantilever beam to wrap the electrode layer in the middle structure; at the same time, appropriately increasing the thickness of the electrode layer, improving the coverage of the electrode layer film at the bridge pier, removing the subsequent thick metal filling process, improving the electrical connection reliability at the bridge pier, thereby simplifying the processing process of the pixel structure and improving the output uniformity of the infrared detector. Compared with the existing infrared detector pixel structure, the main benefits of the present invention are: (1) the thinner electrode structure can greatly improve the thermal insulation performance of the pixel structure; (2) due to the low thermal conductivity and high Young's modulus of the semiconductor dielectric film, a wider cantilever beam structure can be used to improve the strength performance of the pixel microbridge, improve the antistatic characteristics and environmental adaptability of the detector; (3) removing the thick metal layer at the pixel bridge pier, simplifying the processing technology of the pixel microbridge, and improving the processing consistency of the pixel array.

[0067] It should be noted that references in the specification to "an embodiment", "an embodiment", "an exemplary embodiment", "some embodiments", etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same embodiment. In addition, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, whether or not explicitly described, it is within the knowledge of a technician in the relevant art to implement such feature, structure, or characteristic in conjunction with other embodiments.

[0068] Typically, a term can be understood at least in part from usage in context. For example, the term "one or more" as used herein depends at least in part on the context and can be used to describe any feature, structure or characteristic in a singular sense, or can be used to describe a combination of features, structures or features in a plural sense. Similarly, terms such as "one", "a" or "the" can also be understood to express singular usage or to express plural usage, depending at least in part on the context. In addition, the term "based on" can be understood to not necessarily be intended to express a set of exclusive factors, but can alternatively, also at least in part depending on the context, allow for the presence of other factors that are not necessarily explicitly described. It should also be noted in this specification that "connected / coupled" refers not only to the direct coupling of one component to another component, but also to the indirect coupling of one component to another component through an intermediate component.

[0069] It should be noted that the terms "including" and "having" and their variations involved in the documents of the present invention are intended to cover non-exclusive inclusions. The terms "first", "second", etc. are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Unless the context clearly indicates otherwise, it should be understood that the data used in this way can be interchanged under appropriate circumstances. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other unless there is a conflict. In addition, in the above description, the description of well-known components and technologies is omitted to avoid unnecessary confusion of the concepts of the present invention. In the above embodiments, each embodiment focuses on the differences from other embodiments, and the same / similar parts between the embodiments can be referred to each other.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A detector pixel structure, characterized in that: include: substrate; A first microbridge structure, comprising a first pixel bridge pier, a first cantilever beam, and a first bridge deck, wherein the first pixel bridge pier is disposed on the substrate surface, the first cantilever beam is connected to the first pixel bridge pier, and the first bridge deck is connected to the first cantilever beam; A heat-sensitive layer is formed in the first bridge deck; The first cantilever beam includes a first dielectric layer, a second dielectric layer, an electrode layer, and a third dielectric layer stacked in sequence, and the widths of the first dielectric layer, the second dielectric layer, and the third dielectric layer are greater than the width of the electrode layer.

2. The detector pixel structure according to claim 1, characterized in that: The ratio of the width of the electrode layer to the width of the first dielectric layer, the second dielectric layer, and the third dielectric layer is in the range of 1:(1, 4].

3. The detector pixel structure according to claim 1, characterized in that: The thickness of the electrode layer is in the range of 5 nm to 50 nm.

4. The detector pixel structure according to claim 1, characterized in that: The width of the first cantilever beam gradually decreases from a side close to the first pixel bridge pier to a side close to the first bridge deck.

5. The detector pixel structure according to claim 1, characterized in that: The first bridge deck further includes a bridge deck dielectric layer, and the width of the bridge deck dielectric layer is greater than the width of the electrode layer of the first bridge deck.

6. The detector pixel structure according to claim 1, characterized in that: It also includes a second micro-bridge structure, which includes a second pixel bridge pier located above the first bridge deck and a second absorption layer located on both sides of the second pixel bridge pier.

7. The detector pixel structure according to claim 6, characterized in that: The second micro-bridge structure is a semiconductor film or a metal film, and is used to increase the infrared absorption area of ​​the detector pixel structure.

8. The detector pixel structure according to claim 1, characterized in that: The first bridge deck is located above the first cantilever beam, and the first bridge deck is connected to the first cantilever beam through a third pixel bridge pier.

9. The detector pixel structure according to claim 8, characterized in that: A conductive column is disposed in the third pixel bridge pier, and the conductive column is electrically connected to the thermal sensitive layer and the electrode layer.

10. A method for manufacturing a detector pixel structure, characterized in that: The steps include: providing a substrate; Forming a sacrificial layer on the surface of the substrate, wherein the sacrificial layer has a first hole, and the bottom of the first hole exposes the substrate; A first microbridge structure is formed on the surface of the sacrificial layer, the first microbridge structure includes a first pixel bridge pier, a first cantilever beam and a first bridge deck, the first pixel bridge pier is arranged on the surface of the substrate, the first cantilever beam is connected to the first pixel bridge pier, the first bridge deck is connected to the first cantilever beam, a thermosensitive layer is formed in the first bridge deck, the first cantilever beam includes a first dielectric layer, a second dielectric layer, an electrode layer, and a third dielectric layer stacked in sequence, and the widths of the first dielectric layer, the second dielectric layer and the third dielectric layer are greater than the width of the electrode layer; The sacrificial layer is removed.

11. The method according to claim 10, characterized in that Forming a first microbridge structure on the surface of the sacrificial layer further comprises the following steps: Depositing a first dielectric material layer, a heat-sensitive layer and a second dielectric material layer on the surface of the sacrificial layer; Etching the first dielectric material layer and the second dielectric material layer to form a second hole at the bottom of the first hole and a third hole in the second dielectric material layer on the surface of the thermosensitive layer, wherein the bottom of the second hole exposes the substrate and the bottom of the third hole exposes the thermosensitive layer; Depositing an electrode material layer on the surface of the second dielectric material layer, the second hole and the third hole; patterning the electrode material layer to form an electrode layer, wherein the width of the electrode layer is less than a preset threshold; Depositing a third dielectric material layer to form the first pixel bridge pier in the first hole and the first bridge deck at the thermal sensitive layer; The third dielectric material layer, the second dielectric material layer, and the first dielectric material layer are patterned to form the first cantilever beam connecting the first pixel bridge pier and the first bridge deck, and the width of the first dielectric layer, the second dielectric layer, and the third dielectric layer is greater than the width of the electrode layer.

12. The method according to claim 10, characterized in that The following steps are also included: A second microbridge structure is formed above the first microbridge structure, wherein the second microbridge structure includes a second pixel bridge pier located above the first bridge deck and a second absorption layer located on both sides of the second pixel bridge pier.

13. The method according to claim 10, characterized in that Forming a first microbridge structure on the surface of the sacrificial layer further comprises the following steps: Depositing a first dielectric material layer, a second dielectric material layer, and an electrode material layer in sequence on the surface of the sacrificial layer; Patterning the electrode material layer to form an electrode layer, wherein the width of the electrode layer is less than a preset threshold; Depositing a third dielectric material layer to form the first pixel bridge pier in the first hole; Graphically forming the third dielectric material layer, the second dielectric material layer, and the first dielectric material layer to form a first dielectric layer, a second dielectric layer, and a third dielectric layer, wherein the widths of the first dielectric layer, the second dielectric layer, and the third dielectric layer are greater than the width of the electrode layer, and forming the first cantilever beam connected to the first pixel bridge pier; A third pixel bridge pier and a first bridge deck are formed in sequence above the first cantilever beam. A thermal sensitive layer is formed in the first bridge deck and is connected to the first cantilever beam through the third pixel bridge pier.

14. The method according to claim 13, characterized in that A conductive column is disposed in the third pixel bridge pier, and the conductive column is electrically connected to the thermal sensitive layer and the electrode layer.

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