Non-refrigeration infrared detector pixel-level packaging structure and preparation method

Abstract

The invention relates to the technical field of uncooled infrared detectors, in particular to a pixel-level packaging structure of an uncooled infrared detector and a preparation method thereof, which are characterized in that a pixel microbridge structure is manufactured on a substrate with a built-in reading circuit, a bridge column in the pixel microbridge structure is internally provided with a first cavity, and the first cavity is filled with a filling material; and forming a first layer of solid bore log. And forming a cavity structure on the manufactured structure of the first layer, forming a support column with a second cavity inside at the deposition hole of the cavity structure, and filling the second cavity with a filling material to form a solid hole column of a second layer. A release hole is formed in the cavity structure, all sacrificial layers in the cavity structure are released, a cavity structure film layer is deposited to block the release hole so as to seal the whole cavity, and therefore a two-layer solid supporting column structure, namely a column-to-column structure, is formed, the structural stability is greatly enhanced, and the service life of the supporting column is prolonged. And the stability of the structure is further ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of uncooled infrared detectors, and more specifically to a pixel-level packaging structure of an uncooled infrared detector and a preparation method thereof. Background Art

[0002] The pixel-level packaging of uncooled infrared detectors integrates the packaging process into the entire MEMS (micro-electromechanical system) process. On the basis of the completed infrared MEMS microbridge, a specific film layer is used for packaging to achieve thin-film packaging of a single-wafer integrated process. This packaging method is of great significance for improving the performance of the detector, reducing costs and volume. However, in the process of building the entire packaging structure, there are indeed some technical challenges, especially when making columns for cavity support on the microstructure, the columns should be solid columns to ensure the stability of the structure. However, conventional semiconductor long film equipment, such as PVD (physical vapor deposition) and CVD (chemical vapor deposition), often have problems in filling small holes. During the filling process, these devices are prone to empty plating in the middle of the hole due to the influence of factors such as airflow and temperature distribution, that is, the film layer fails to completely cover the hole wall, forming a void, resulting in poor structural stability.

[0003] Similar prior art includes a Chinese patent application with publication number CN117613108A, which discloses a pixel-level packaging structure and packaging method; the packaging structure includes a pixel unit, including a readout circuit substrate and a microbridge structure disposed on the readout circuit substrate; a packaging cap is supported on the readout circuit substrate and forms a packaging cavity with the readout circuit substrate, so that the microbridge structure is placed in the packaging cavity; the supporting part of the packaging cap supported on the readout circuit substrate is a getter structure. Although the stability of the pixel packaging structure has been greatly improved, the stability of the pixel packaging structure is still poor.

[0004] Similar prior art includes a Chinese patent application with publication number CN116902905A, which discloses an infrared detector chip wafer and an infrared detector packaging structure and preparation method. The infrared detector chip wafer includes a substrate wafer, an epitaxial layer, an interlayer dielectric, an integrated circuit, and a microbolometer connected to the integrated circuit; a through hole penetrating the interlayer dielectric, the epitaxial layer and the substrate wafer is provided at the integrated circuit, and an insulating layer is provided on the side wall of the through hole, and a conductive material is filled in the through hole to connect the integrated circuit to the conductive material; a conductive structure connected to the conductive material is provided on the lower surface of the substrate wafer, so that the integrated circuit is connected to the external circuit through the conductive structure. Although this application can improve the interconnection reliability, reduce signal transmission delay and packaging volume, it does not consider the stability of the pixel packaging structure.

[0005] Therefore, the present invention provides a non-cooled infrared detector pixel level packaging structure and a preparation method. Summary of the invention

[0006] Conventional semiconductor film growth equipment, such as PVD (physical vapor deposition) and CVD (chemical vapor deposition), often have problems filling small holes. During the filling process, these devices are prone to empty plating in the middle of the hole due to the influence of factors such as airflow and temperature distribution. That is, the film layer fails to completely cover the hole wall, forming a void, resulting in poor structural stability.

[0007] In order to better solve the above problems, the present invention provides a non-cooled infrared detector pixel-level packaging structure and a preparation method, wherein the non-cooled infrared detector pixel-level packaging structure comprises:

[0008] A substrate with built-in readout circuitry;

[0009] A pixel micro-bridge structure located on the substrate, the pixel micro-bridge structure comprising a bridge deck and a bridge column supporting the bridge deck, the bridge column having a first cavity inside, the first cavity being filled with a filling material to form a first layer of solid hole columns;

[0010] A cavity structure covering the pixel micro-bridge structure has a support column supported on the bridge column, a second cavity is formed inside the support column, and the second cavity is filled with a filling material to form a second layer of solid hole columns.

[0011] As a preferred technical solution of the present invention, the cavity structure is provided with a release hole, and the surface of the cavity structure is covered with a cavity structure film layer, and the cavity structure film layer blocks the release hole.

[0012] As a preferred technical solution of the present invention, the cavity structure has one or more pixel micro-bridge structures.

[0013] As a preferred technical solution of the present invention, the filling material filled in the first cavity is flush with the top surface of the bridge column;

[0014] The filling material filled in the second cavity is flush with the top surface of the supporting column.

[0015] As a preferred technical solution of the present invention, the filling material is resin, metal or compound.

[0016] The preparation method of the pixel-level packaging structure of an uncooled infrared detector is realized by performing the following steps:

[0017] Step S1: manufacturing a pixel micro-bridge structure based on a sacrificial layer on a substrate with a built-in readout circuit, wherein the pixel micro-bridge structure comprises a bridge deck and a bridge column supporting the bridge deck, and a first cavity is formed inside the bridge column;

[0018] Step S2: Filling the first cavity with a filling material to form a first layer of solid hole columns;

[0019] Step S3: coating a sacrificial layer on the structure manufactured in step S2, etching the sacrificial layer above the bridge column to form a deposition hole, and then depositing a cavity material to form a cavity structure covering the pixel microbridge structure, wherein the cavity structure forms a support column having a second cavity inside at the deposition hole, and the second cavity is filled with a filling material to form a second layer of solid hole column;

[0020] Step S4: a release hole is opened on the cavity structure to release all sacrificial layers in the cavity structure, and then a cavity structure film layer is deposited to block the release hole to seal the entire cavity.

[0021] As a preferred technical solution of the present invention, the filling material is a resin material, and the method of filling the first cavity with the filling material or filling the second cavity with the filling material is as follows:

[0022] Apply liquid filling material on the first cavity or the second cavity and let it stand for a preset time until the first cavity or the second cavity is filled with the filling material, bake the filling material at high temperature, and then remove the filling material outside the first cavity or the second cavity.

[0023] As a preferred technical solution of the present invention, the filling material is a metal or a compound, and the method of filling the first cavity with the filling material or filling the second cavity with the filling material is as follows:

[0024] A filling material is deposited above the first cavity or the second cavity until the first cavity or the second cavity is fully filled with the filling material, and then the filling material outside the first cavity or the second cavity is removed.

[0025] As a preferred technical solution of the present invention, the filling material is baked at the high temperature, and the high temperature refers to a temperature between 150 degrees and 300 degrees.

[0026] As a preferred technical solution of the present invention, the filling material is baked at the high temperature, and the baking time is until the filling material solidifies in the first cavity or the second cavity.

[0027] Compared with the prior art, the beneficial effects of the present invention are at least as follows:

[0028] The technical solution of the present invention adopts a pixel-level packaging structure, by manufacturing a pixel micro-bridge structure based on a sacrificial layer on a substrate with a built-in readout circuit. The bridge column in the pixel micro-bridge structure has a first cavity inside, and the first cavity is filled with filling material to form a first layer of solid hole columns.

[0029] A sacrificial layer is coated on the structure manufactured on the first layer, and the sacrificial layer above the bridge column is etched to form a deposition hole. Then, the cavity material is deposited to form a cavity structure covering the pixel micro-bridge structure. The cavity structure forms a support column with a second cavity inside at the deposition hole, and the second cavity is filled with filling material to form a solid hole column of the second layer.

[0030] A release hole is also opened on the cavity structure to release the sacrificial layer in the cavity structure, and then a layer of cavity structure film is deposited to seal the release hole to close the entire cavity, thereby forming a two-layer solid support column structure, that is, a column-on-column structure, which greatly enhances the structural stability and further ensures the stability of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0032] Figure 1 It is a schematic diagram of the pixel-level packaging structure of the uncooled infrared detector in the present invention;

[0033] Figure 2 This is a schematic diagram of the first layer of the uncooled infrared detector pixel-level packaging structure of the present invention after the filling material is applied;

[0034] Figure 3 It is a schematic diagram of the pixel-level packaging structure of the uncooled infrared detector in the present invention after removing the external filling material;

[0035] Figure 4 It is a schematic diagram of the second layer cavity structure of the uncooled infrared detector pixel level packaging structure in the present invention;

[0036] Figure 5 It is a schematic diagram of the cavity structure sealing by the cavity structure film layer in the present invention;

[0037] Figure 6 The solid support column structure after the sacrificial layer is removed in the present invention;

[0038] Figure 7 A schematic diagram of a plurality of pixels in a cavity in the present invention;

[0039] In the figure: 1. substrate; 2. pixel microbridge structure; 3. first cavity; 4. bridge column; 5. cavity structure; 6. sacrificial layer; 7. second cavity; 8. filling material; 9. release hole; 10. cavity structure membrane layer. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but unless otherwise specified, these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first xx script may be referred to as a second xx script, and similarly, a second xx script may be referred to as a first xx script.

[0042] The pixel-level packaging of uncooled infrared detectors integrates the packaging process into the entire MEMS (micro-electromechanical system) process. On the basis of the completed infrared MEMS microbridge, a specific film layer is used for packaging to achieve thin-film packaging of a single-wafer integrated process. This packaging method is of great significance for improving the performance of the detector and reducing costs and volume. However, in the process of building the entire packaging structure, there are indeed some technical challenges, especially when making columns for cavity support on the microstructure, the columns should be solid columns to ensure the stability of the structure. However, conventional semiconductor long film equipment, such as PVD (physical vapor deposition) and CVD (chemical vapor deposition), often have problems in filling small holes. During the filling process, these devices are prone to empty plating in the middle of the hole due to the influence of factors such as airflow and temperature distribution, that is, the film layer fails to completely cover the hole wall, forming a void, resulting in poor structural stability.

[0043] In view of the above technical problems, the present invention proposes a non-cooled infrared detector pixel level packaging structure and a preparation method, the non-cooled infrared detector pixel level packaging structure, such as Figure 1-Figure 7 As shown, including:

[0044] The substrate 1 with built-in readout circuit first selects high-purity silicon as the substrate material, and uses standard semiconductor process technology to prepare the substrate 1 with good electrical properties and mechanical strength. The infrared readout circuit is integrated on the substrate 1 for subsequent reception and processing of infrared signals.

[0045] A pixel micro-bridge structure 2 is located on a substrate 1, and the pixel micro-bridge structure 2 includes a bridge deck and a bridge column 4 supporting the bridge deck. The bridge column 4 has a first cavity 3 inside, and the first cavity 3 is filled with a filling material 8 to form a first layer of solid hole columns;

[0046] Specifically, a pixel microbridge structure 2 is precisely machined above the substrate 1 using micromachining technology (such as deep reactive ion etching DRIE). The pixel microbridge structure 2 includes a bridge column 4, a bridge deck, and a bridge leg. A first cavity 3 is formed inside the bridge column 4 during deposition. The bridge deck is connected to the bridge column 4 through the bridge leg. The size and material of the bridge column 4, the bridge deck, and the bridge leg are precisely controlled according to the design requirements of the infrared detector to ensure effective absorption and conduction of infrared radiation.

[0047] The pixel micro-bridge structure 2 is manufactured based on the sacrificial layer 6, and the sacrificial material will be removed in subsequent steps to form the desired cavity structure.

[0048] The cavity structure 5 covering the pixel micro-bridge structure 2 has a support column supported on the bridge column 4, and a second cavity 7 is formed inside the support column. The second cavity 7 is filled with a filling material 8 to form a second layer of solid hole columns.

[0049] Specifically, the cavity structure 5 is also made based on the sacrificial layer 6, and the micromachining technology or chemical vapor deposition technology is used again to deposit one or more layers of materials to construct the cavity structure 5. During the deposition process of the cavity structure 5, due to the obstruction of the bridge column 4, a support column with a second cavity 7 is naturally formed above it, and finally a complete cavity structure 5 is formed. The cavity structure 5 helps to reduce heat conduction and improve the sensitivity of the infrared detector.

[0050] Subsequently, a hole is opened at a specific position on the cavity structure 5 to form a release hole 9, which is used for the subsequent release of the sacrificial layer 6, and the sacrificial layer 6 is selectively removed by wet etching or dry etching to expose the cavity between the bridge column 4 and the cavity structure 5. There can be multiple specific positions, and the specific positions are only required to facilitate the release of the sacrificial layer material. In addition, after the sacrificial layer is released, the release hole (9) is necessary to be blocked by the cavity structure film layer 10, such as depositing a protective layer, installing an infrared transparent window, etc., to protect the internal structure from the external environment.

[0051] Preferably, the filling material is a resin, a metal or a compound, wherein the resin is such as polyimide, the metal is such as tungsten or copper, and the compound is such as silicon nitride and silicon oxide. When the filling material is a resin, according to the design requirements, a layer of filling material 8 is applied on the surface of the first cavity 3 so that the first cavity 3 is filled with the filling material 8; the filling material 8 is baked at a high temperature to remove the water vapor inside the filling material 8, so that the material is more solid.

[0052] Preferably, the filling material 8 filled in the first cavity 3 is flush with the top surface of the bridge column 4; the filling material 8 filled in the second cavity 7 is flush with the top surface of the support column.

[0053] The cavity structure may have only one pixel micro-bridge structure or multiple pixel micro-bridge structures, both of which are within the protection scope of the present invention.

[0054] A method for preparing an uncooled infrared detector pixel-level packaging structure is implemented by performing the following steps:

[0055] Step S1: A pixel micro-bridge structure 2 is manufactured on a substrate 1 with a built-in readout circuit based on a sacrificial layer 6. The pixel micro-bridge structure 2 includes a bridge deck and a bridge column 4 supporting the bridge deck. The bridge column 4 has a first cavity 3 inside.

[0056] Specifically, Figure 1 As shown, a sacrificial layer 6 of a certain thickness is first spin-coated on the substrate 1, and a pixel microbridge structure 2 is precisely processed based on the sacrificial layer 6 using micromachining technology (such as deep reactive ion etching DRIE). The pixel microbridge structure 2 includes a bridge column 4, a bridge deck, and bridge legs. The bridge deck is connected to the bridge column 4 through the bridge legs, and a first cavity 3 is formed inside the bridge column 4 during deposition.

[0057] Step S2: Fill the first cavity 3 with a filling material 8 to form a first layer of solid hole columns.

[0058] A layer of filling material 8 is applied on the surface of the first cavity 3 of the bridge column 4. After application, it is left to stand for a period of time to ensure that the filling material 8 fully penetrates into the first cavity 3 and fills the gap. Figure 2 As shown, then, through high-temperature baking treatment, the water vapor inside the filling material 8 is removed to make the material stronger. The filling material 8 will solidify and fit tightly to the wall of the first cavity 3 to form a preliminary structure of a solid lower layer hole column. For example, polyimide (PI) glue can be used as a filling material. At room temperature, the polyimide (PI) glue is evenly coated on the surface of the wafer by spin coating, because polyimide (PI) glue has excellent high temperature resistance and chemical stability. After applying, let it stand for 24 hours to ensure sufficient penetration. Subsequently, the sample is placed in an oven and baked at 200°C for 4 hours to completely cure the PI glue. The specific baking temperature and duration of different glue materials are different, and need to be determined according to the characteristics of the glue material.

[0059] After the filling material 8 is cured, the filling material 8 outside the first cavity 3 is removed. Specifically, the filling material 8 outside the first cavity 3 is removed by an etching process, such as wet etching or dry etching, while the filling material 8 inside is retained. Figure 3As shown. In this way, the original first cavity 3 becomes a solid lower layer hole column filled with filling material 8. The key to this step is to accurately control the etching process to avoid damaging the structure inside the first cavity 3. During etching, use an appropriate etching solution (such as dilute sulfuric acid or sodium hydroxide solution) to etch the sample, and at the same time, by accurately controlling the etching time and temperature, ensure that only the PI glue outside the first cavity 3 is removed without affecting the internal structure. After etching, wash the sample with deionized water to remove the residual etching solution and blow dry.

[0060] Step S3: Coat a sacrificial layer 6 on the structure manufactured in the above step S2, etch the sacrificial layer 6 above the bridge column 4 to form a deposition hole, and then deposit the cavity material to form a cavity structure 5 covering the pixel microbridge structure 2. The cavity structure 5 forms a support column with a second cavity 7 inside at the deposition hole, and fills the second cavity 7 with filling material 8 to form a second layer of solid hole column.

[0061] Specifically, Figure 4 As shown, on the basis of completing the first layer structure, the second layer structure is built. First, a sacrificial layer 6 is coated on the structure manufactured in the above step S2, and the sacrificial layer 6 above the bridge column 4 is etched to form a deposition hole, so that when the cavity material is subsequently deposited, part of the cavity material falls on the deposition hole and is supported on the top of the solid hole of the first layer to support the cavity structure 5. Then the cavity material is deposited to form a cavity structure 5 covering the pixel microbridge structure 2, and the cavity structure 5 forms a support column with a second cavity 7 inside at the deposition hole. Subsequently, the second cavity 7 is filled with the same process as the above step S1 and the above step S2 to form a solid upper support column. It is important that the second cavity 7 needs to be aligned with the first cavity 3 to ensure the stability of the overall structure.

[0062] Step S4: a release hole 9 is opened on the cavity structure 5 to release all the sacrificial layers 6 in the cavity structure 5, and then a cavity structure film layer is deposited to block the release hole 9 to seal the entire cavity.

[0063] Specifically, Figure 5As shown, after completing the filling of the second cavity 7, a cavity structure film layer 10 is deposited again to close the entire cavity structure. The cavity structure film layer 10 needs to have good air tightness and thermal stability to ensure a high vacuum environment inside the packaging structure. For example, aluminum oxide (Al2O3) can be used as the cavity structure film layer material, and aluminum oxide has good thermal stability and chemical inertness. A uniform Al2O3 film layer is deposited on the entire structure by physical vapor deposition (PVD) or chemical vapor deposition (CVD) technology, and the thickness is controlled between a few nanometers and tens of nanometers to ensure good air tightness, thereby completing the production of the entire cavity. At this point, the double-layer structure solid support column process has been completed, and the same preparation method can also be used to complete the multi-layer structure solid support column process. Among them, the pore size of the release hole 9 is between 0.3-2 microns, and the number of release holes can be one or more.

[0064] Specifically, all sacrificial layers 6 in the packaging structure are removed by etching process to form the final hollow uncooled infrared detector pixel-level packaging structure, such as Figure 6 As shown. The sacrificial layer 6 is usually used to provide temporary support or structure during the manufacturing process, but needs to be removed in the final product. When removing the sacrificial layer 6, it is necessary to select a suitable etching method according to the material properties of the sacrificial layer 6. If the material of the sacrificial layer 6 is a polymer material, an organic solvent can be used for dissolution and removal; if it is an inorganic material, wet or dry etching technology may be required. In this example, assuming that the material of the sacrificial layer 6 is polymethyl methacrylate (PMMA), acetone is used as a solvent for dissolution and removal. After etching, the sample is washed with deionized water to remove residual solvent, and blown dry. The final uncooled infrared detector pixel-level packaging structure is supported by multiple layers of solid support columns to form a stable hollow structure.

[0065] Through the coordination between the above steps, a two-layer solid support column structure is formed, namely the column-top-column structure, and the upper and lower support columns in the column-top-column structure are both solid support columns, which greatly enhances the structural stability and further ensures the stability of the structure.

[0066] Furthermore, the filling material 8 is a resin material, such as polyimide, and the method of filling the first cavity 3 with the filling material 8 or filling the second cavity 7 with the filling material 8 is as follows:

[0067] Liquid filling material 8 is applied on the top of the first cavity 3 or the second cavity 7 and left to stand for a preset time until the first cavity 3 or the second cavity 7 is filled with the filling material 8, the filling material 8 is baked at high temperature, and then the filling material 8 outside the first cavity 3 or the second cavity 7 is removed.

[0068] Furthermore, the filling material 8 is a metal or a compound, such as tungsten or copper, or a compound such as silicon nitride or silicon oxide. The method of filling the first cavity 3 with the filling material or the second cavity 7 with the filling material is as follows:

[0069] A filling material 8 is deposited above the first cavity 3 or the second cavity 7 until the first cavity 3 or the second cavity 7 is completely filled with the filling material 8 , and then the filling material 8 outside the first cavity 3 or the second cavity 7 is removed.

[0070] Furthermore, the filling material 8 is baked at a high temperature, where the high temperature refers to a temperature between 150 degrees and 300 degrees.

[0071] Specifically, in the preparation process of the pixel-level packaging structure of the uncooled infrared detector, the first cavity 3 or the second cavity 7 filled with liquid glue material is baked at high temperature to make the liquid glue material (such as polyimide PI glue) undergo a cross-linking reaction, thereby solidifying into a hard solid. Although high-temperature baking can solidify glue materials, excessively high temperatures may cause damage to the first cavity 3 or the second cavity 7 itself or other adjacent materials. Therefore, limiting the baking temperature to between 150 degrees and 300 degrees can ensure that the overall performance and stability of the packaging structure will not be destroyed while curing the glue material. In actual operation, the specific baking temperature and time can be set according to the characteristics of the selected liquid glue material (such as curing temperature, thermal stability, etc.) and the actual needs of the packaging structure. For example, if polyimide PI glue is selected as the filling material, it can be baked in the temperature range of 200°C to 250°C, and the baking time is determined according to the thickness of the glue layer and the efficiency of the baking equipment, usually ranging from several hours to more than ten hours. The temperature and time need to be strictly controlled during the baking process to ensure that the glue material can be completely cured and meet the required performance requirements.

[0072] Furthermore, the filling material 8 is baked at a high temperature until the filling material 8 is solidified in the first cavity 3 or the second cavity 7 .

[0073] Specifically, during the high-temperature baking process, for the liquid filling material 8 in the first cavity 3 or the second cavity 7, the baking time directly affects whether the filling material 8 can be completely solidified in the first cavity 3 or the second cavity 7. The length of the baking time first depends on the characteristics of the selected filling material 8, including its curing temperature, curing rate, thermal stability, etc. Different filling materials 8 may require different baking times and temperatures to achieve the ideal solidification effect. At the same time, the size of the first cavity 3 or the second cavity 7 will also affect the baking time. Larger pore columns may require longer baking times to ensure that the glue material can fully penetrate into every corner of the pore column and completely solidify. In addition, during the baking process, the baking temperature and baking time need to be strictly controlled to avoid material damage or performance degradation due to excessively high temperature or too long time.

[0074] In summary, the present invention adopts a pixel-level packaging structure, and a pixel micro-bridge structure is manufactured based on a sacrificial layer on a substrate with a built-in readout circuit. The bridge column in the pixel micro-bridge structure has a first cavity inside, and the first cavity is filled with a filling material to form a first layer of solid hole columns. A sacrificial layer is coated on the first layer of the completed structure, and the sacrificial layer above the bridge column is etched to form a deposition hole, and then the cavity material is deposited to form a cavity structure covering the pixel micro-bridge structure. The cavity structure forms a support column with a second cavity inside at the deposition hole, and the second cavity is filled with a filling material to form a second layer of solid hole columns. A release hole is also opened on the cavity structure to release all the sacrificial layers in the cavity structure, and then a layer of cavity structure film is deposited to block the release hole to close the entire cavity, thereby forming a two-layer solid support column structure, that is, a column-on-column structure, which greatly enhances the stability of the structure and further ensures the stability of the structure. The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

[0076] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An uncooled infrared detector pixel level packaging structure, characterized in that: The packaging structure comprises: A substrate (1) having a built-in readout circuit; A pixel microbridge structure (2) located on the substrate (1), the pixel microbridge structure (2) comprising a bridge deck and a bridge column (4) supporting the bridge deck, the bridge column (4) having a first cavity (3) inside, the first cavity (3) being filled with a filling material (8) to form a first layer of solid hole columns; A cavity structure (5) covering the pixel microbridge structure (2), the cavity structure (5) having a support column supported on the bridge column (4), the support column having a second cavity (7) inside, the second cavity (7) being filled with a filling material (8) to form a second layer of solid hole columns.

2. The uncooled infrared detector pixel level packaging structure according to claim 1, characterized in that: The cavity structure (5) is provided with a release hole (9), and the surface of the cavity structure (5) is covered with a cavity structure film layer (10), and the cavity structure film layer (10) blocks the release hole (9).

3. The uncooled infrared detector pixel level packaging structure according to claim 1, characterized in that: The cavity structure (5) has one or more pixel micro-bridge structures (2) therein.

4. The uncooled infrared detector pixel level packaging structure according to claim 1, characterized in that: The filling material (8) filled in the first cavity (3) is flush with the top surface of the bridge column (4); The filling material (8) filled in the second cavity (7) is flush with the top surface of the support column.

5. The uncooled infrared detector pixel level packaging structure according to claim 1, characterized in that: The filling material (8) is resin, metal or compound.

6. A method for preparing a pixel-level packaging structure of an uncooled infrared detector, characterized in that: The preparation method comprises the following steps: Step S1: A pixel microbridge structure (2) is manufactured on a substrate (1) with a built-in readout circuit based on a sacrificial layer (6), wherein the pixel microbridge structure (2) comprises a bridge deck and a bridge column (4) supporting the bridge deck, and the bridge column (4) has a first cavity (3) inside; Step S2: Filling the first cavity (3) with a filling material (8) to form a first layer of solid pore columns; Step S3: coating a sacrificial layer (6) on the structure manufactured in step S2, etching the sacrificial layer (6) above the bridge column (4) to form a deposition hole, and then depositing a cavity material to form a cavity structure (5) covering the pixel microbridge structure (2), wherein the cavity structure (5) forms a support column having a second cavity (7) inside at the deposition hole, and the second cavity (7) is filled with a filling material (8) to form a second layer of solid hole column; Step S4: a release hole (9) is opened on the cavity structure (5) to release all sacrificial layers (6) in the cavity structure (5), and then a cavity structure film layer is deposited to block the release hole (9) to seal the entire cavity.

7. The method for preparing the uncooled infrared detector pixel level packaging structure according to claim 6, characterized in that: The filling material (8) is a resin material. The method of filling the first cavity (3) with the filling material (8) or filling the second cavity (7) with the filling material (8) is as follows: A liquid filling material (8) is applied above the first cavity (3) or the second cavity (7), and allowed to stand for a preset time until the first cavity (3) or the second cavity (7) is fully filled with the filling material (8), the filling material (8) is baked at a high temperature, and then the filling material (8) outside the first cavity (3) or the second cavity (7) is removed.

8. The method for preparing the uncooled infrared detector pixel level packaging structure according to claim 6, characterized in that: The filling material (8) is a metal or a compound. The method for filling the first cavity (3) with the filling material or the method for filling the second cavity (7) with the filling material is as follows: A filling material (8) is deposited above the first cavity (3) or the second cavity (7) until the first cavity (3) or the second cavity (7) is completely filled with the filling material (8), and then the filling material (8) outside the first cavity (3) or the second cavity (7) is removed.

9. The method for preparing the uncooled infrared detector pixel level packaging structure according to claim 7, characterized in that: The filling material (8) is baked at the high temperature, wherein the high temperature is a temperature between 150 degrees and 300 degrees.

10. The method for preparing the uncooled infrared detector pixel level packaging structure according to claim 7, characterized in that: The filling material (8) is baked at the high temperature, and the baking time is until the filling material (8) is solidified in the first cavity (3) or the second cavity (7).

Images