Three-dimensional stacked infrared detector structure and method of manufacturing the same

Abstract

This invention provides a three-dimensional stacked infrared detector structure, comprising: an infrared detector chip including an infrared sensing array region, a first pad region disposed around the infrared sensing array region, and a first metallization ring surrounding the infrared sensing array region and the first pad region, the first pad region including a plurality of first pads; a ceramic adapter ring disposed on the infrared detector chip, including a window and an annular body disposed around the window, the window corresponding to the infrared sensing array region, the lower surface of the annular body including a second pad region disposed around the window and a second metallization ring surrounding the window and the second pad region. The second pad area includes multiple second pads, which are soldered to the first pads. The second metallized ring is soldered to the first metallized ring. The upper surface of the annular body includes a third pad area disposed around the window and a third metallized ring disposed at the edge of the window. The third pad area includes multiple third pads. The second pads are electrically connected to the third pads through conductive lines disposed within the annular body. The spacing between two adjacent third pads is greater than the spacing between two adjacent first pads. A window covers the window and is soldered to the third metallized ring. Solder balls are disposed on the third pads. This invention can reduce the overall size of the infrared detector structure, eliminate the fragile wire bonding structure and simplify the protection design, overcome the interconnection limitations caused by the small-sized pads of the detector chip, and simultaneously increase the sealed cavity volume and extend the service life of the package vacuum.

Description

Technical Field

[0001] This invention relates to the field of infrared detectors, and more particularly to a three-dimensional stacked infrared detector structure and its manufacturing method. Background Technology

[0002] Currently, the mainstream packaging forms of MEMS infrared focal plane detectors in the industry are mainly divided into three categories: metal packaging, ceramic packaging, and wafer-level packaging. Among them, traditional metal packaging and ceramic packaging technologies are mature and have high process stability, but due to their own structural design and assembly process limitations, the overall packaging volume is relatively large, making it difficult to meet the current development needs of miniaturization and lightweighting of equipment. Wafer-level packaging, with its outstanding advantages of high integration and compact structure, can effectively reduce the overall size of the device and is the preferred solution for miniaturized detection equipment. However, this packaging solution still has many application shortcomings.

[0003] like Figure 1 As shown, this is a schematic diagram of wire bonding for a wafer-level packaged detector chip. The wafer-level packaged detector chip 100 is mounted on the chip mounting area 140 of the PCB board 110. The lead-out pads (PADs) 120 of the detector chip 100 for signal transmission are arranged in the peripheral area of ​​the detector chip 100 and are directly exposed. In the actual assembly and use of the whole machine, it is necessary to use the wire bonding process to connect the exposed lead-out pads 120 of the detector chip 100 to the back-end PCB board 110 through metal leads 130, so as to complete the normal transmission and docking of the detector's electrical signals.

[0004] In this type of packaging structure, the pad size of the detector chip itself is small, and electrical interaction can only be achieved through wire bonding in later applications. However, the metal wires used for wire bonding have low mechanical strength and are very fragile, easily breaking under external forces, leading to electrical connection failure. Therefore, existing wafer-level packaged detector chips require protection of the metal wires through methods such as coating with protective adhesive and adding mechanical shielding. These additional protective structures prevent the existing packaging method from further meeting the market's demand for miniaturized products. Meanwhile, in existing wafer-level packaged detectors, the sealing metallization ring 150 only encloses the central sensitive array area, with the exposed pads on the outside of the sealing metallization ring 150. This not only reduces the design margin of the sealing metallization ring but also results in a smaller sealed cavity volume, ultimately significantly shortening the lifespan of the device's packaged vacuum.

[0005] Therefore, how to reduce the overall size of the infrared detector structure, abandon the fragile wire bonding structure and simplify the protection design, get rid of the interconnection limitations caused by the small-sized pads of the detector chip, and at the same time increase the volume of the sealed cavity and extend the service life of the packaged vacuum have become the technical problems that urgently need to be solved. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a three-dimensional stacked infrared detector structure and its manufacturing method, which can reduce the overall volume of the infrared detector structure, eliminate the fragile wire bonding structure and simplify the protection design, get rid of the interconnection limitations caused by the small-sized pads of the detector chip, and at the same time increase the volume of the sealed cavity and extend the service life of the packaged vacuum.

[0007] To address the aforementioned problems, this invention provides a three-dimensional stacked infrared detector structure, comprising: an infrared detector chip including an infrared sensing array region, a first pad region disposed around the infrared sensing array region, and a first metallization ring surrounding the infrared sensing array region and the first pad region, the first pad region including a plurality of first pads; and a ceramic adapter ring disposed on the infrared detector chip, including a window and an annular body disposed around the window, the window corresponding to the infrared sensing array region, the lower surface of the annular body including a second pad region disposed around the window and a second metallization ring surrounding the window and the second pad region. The system comprises a metallized ring, a second pad area including multiple second pads, the second pads being soldered to the first pads, and the second metallized ring being soldered to the first metallized ring. The upper surface of the annular body includes a third pad area disposed around the periphery of the window and a third metallized ring disposed at the edge of the window. The third pad area includes multiple third pads, and the second pads are electrically connected to the third pads via conductive lines passing through the annular body. The spacing between two adjacent third pads is greater than the spacing between two adjacent first pads. A window pane covers the window and is soldered to the third metallized ring. Solder balls are disposed on the third pads.

[0008] In one embodiment, the plurality of first pads are all disposed on the same side of the infrared sensing array region, or the plurality of first pads are respectively disposed on different sides of the infrared sensing array region.

[0009] In one embodiment, the upper surface of the annular body further includes a stepped area disposed at the edge of the window, the stepped area extending toward the infrared detector chip, the third metallized ring being disposed on the stepped surface of the stepped area, and the window being located within the area surrounded by the stepped area.

[0010] In one embodiment, the upper surface of the window is lower than the upper surface of the annular body, or the upper surface of the window is flush with the upper surface of the annular body.

[0011] In one embodiment, the lower surface of the annular body further includes a getter attachment area located within the area surrounded by the second metallized ring; the three-dimensional stacked infrared detector structure further includes a getter disposed in the getter attachment area.

[0012] In one embodiment, the getter attachment area and the second pad area are located on the same side of the window.

[0013] In one embodiment, the upper surface of the annular body further includes a getter electroactivation point, which is electrically connected to the getter via a conductive line passing through the annular body.

[0014] In one embodiment, the getter electroactivation point and the third pad area are located on the same side of the window.

[0015] In one embodiment, the three-dimensional stacked infrared detector structure further includes a breathable barrier structure disposed between the getter attachment area and the infrared sensing array area to block particulate matter falling from the getter.

[0016] In one embodiment, the infrared detector chip, the main body, the first metallized ring, and the second metallized ring have the same outer diameter.

[0017] In one embodiment, the thickness of the ceramic adapter ring is greater than or equal to 0.6 mm.

[0018] To address the aforementioned technical problems, the present invention also provides a method for manufacturing the above-mentioned three-dimensional stacked infrared detector structure, comprising the following steps: placing the infrared detector chip on a tooling fixture; placing a pre-fabricated first solder ring on the first metallized ring of the infrared detector chip; placing a ceramic adapter ring with a pre-fabricated getter and a gas-permeable barrier structure above the first solder ring; placing a pre-fabricated second solder ring on the third metallized ring above the ceramic adapter ring; placing the window above the second solder ring; reflow soldering; attaching solder balls to the pre-fabricated third pad of the ceramic adapter ring; placing the package with attached solder balls into a reflow oven for reflow soldering, so that the solder balls are soldered onto the third pad of the ceramic adapter ring; activating the getter.

[0019] The above technical solution utilizes the internal conductive lines of a ceramic adapter ring to transfer the small-pitch first pad of the infrared detector chip to the large-pitch third pad on the upper surface of the ceramic adapter ring, and uses solder balls to achieve external interconnection. This completely eliminates the easily broken wire bonding structure that requires additional protection, improves the reliability of electrical connections, simplifies protection design, and frees up space for miniaturization design. Furthermore, the first pad area of ​​the infrared detector chip is entirely included within the sealed area, effectively increasing the volume of the sealed cavity, improving the problem of insufficient cavity space, and significantly extending the vacuum retention life of the package. Simultaneously, the multi-layer metallized rings are welded together, and the window is sealed to the ceramic adapter ring, ensuring the overall hermeticity and structural stability of the package, comprehensively improving the packaging performance and reliability of the MEMS infrared focal plane detector. The three-dimensional stacked infrared detector structure provided by this invention uses a ceramic adapter ring to achieve three-dimensional stacked vacuum packaging and electrical interconnection, significantly reducing the overall package volume and overcoming the shortcomings of traditional metal and ceramic packages which are relatively large in size.

[0020] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of wire bonding for an existing wafer-level packaged detector chip; Figure 2 This is a top view schematic diagram of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention; Figure 3 It is along Figure 2 Schematic diagram of the cross section of line A-A1; Figure 4 It is along Figure 2 Schematic diagram of the cross section of line B-B1; Figure 5 It is along Figure 2 Schematic diagram of the cross section of line C-C1; Figure 6 This is an exploded view of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention; Figure 7 yes Figure 3 Enlarged schematic diagram of region D in the middle; Figure 8 This is a top view schematic diagram of an infrared detector chip with a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention; Figure 9 This is a top view schematic diagram of an infrared detector chip with a three-dimensional stacked infrared detector structure provided in another embodiment of the present invention; Figure 10 This is a bottom view schematic diagram of a ceramic adapter ring for a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention; Figure 11 This is a top view schematic diagram of a ceramic adapter ring for a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention; Figure 12 This is a top view schematic diagram of the window of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention; Figure 13 This is a bottom view schematic diagram of the window of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures: 100. Detector chip; 110. PCB board; 120. Lead pad; 130. Metal lead; 140. Chip mounting area; 150. Sealing ring metal ring; 200. Infrared detector chip; 201. Infrared sensing array area; 202. First pad; 203. First metallized ring; 204. Substrate; 210. Ceramic adapter ring; 211. Window; 212. Ring body; 2121. Step area; 213. 214. Second metallization ring; 215. Third pad; 216. Third metallization ring; 217. Conductive line; 218. Getter adhesion area; 219. Getter electro-activation point; 220. Window; 221. First antireflection film; 222. Second antireflection film; 223. Fourth metallization ring; 230. Solder ball; 240. Getter; 250. Gas-permeable barrier structure; 260. First solder ring; 270. Second solder ring. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Figure 2 This is a top view schematic diagram of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention. Figure 3 It is along Figure 2A cross-sectional diagram of line A-A1 in the middle. Figure 4 It is along Figure 2 Schematic diagram of the cross section of line B-B1. Figure 5 It is along Figure 2 A schematic diagram of the cross-section of line C-C1. Figure 6 This is an exploded view of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention. Figure 7 yes Figure 3 An enlarged diagram of region D in the middle, as shown below. Figures 2-7 As shown, the three-dimensional stacked infrared detector structure includes an infrared detector chip 200, a ceramic adapter ring 210, a window 220, and solder balls 230. Figure 6 Solder ball 230 is not shown in the drawing.

[0026] The infrared detector chip 200 includes an infrared sensing array area 201, a first pad area disposed around the infrared sensing array area 201, and a first metallization ring 203 surrounding the infrared sensing array area 201 and the first pad area. The first pad area includes a plurality of first pads 202.

[0027] The ceramic adapter ring 210 is disposed on the infrared detector chip 200, including a window 211 and an annular body 212 disposed around the window 211. The window 211 corresponds to the infrared sensing array area 201. The lower surface of the annular body 212 includes a second pad area disposed around the window 211 and a second metallization ring 214 surrounding the window 211 and the second pad area. The second pad area includes a plurality of second pads 213. The second pads 213 are soldered to the first pads 202. The second metallization ring 214 is soldered to the first metallization ring 203. The upper surface of the annular body 212 includes a third pad area disposed around the window 211 and a third metallization ring 216 disposed at the edge of the window 211. The third pad area includes a plurality of third pads 215. The second pads 213 are electrically connected to the third pads 215 through conductive lines 217 disposed in the annular body 212. The spacing between two adjacent third pads 215 is greater than the spacing between two adjacent first pads 202.

[0028] The window slab 220 covers the window 211 and is welded to the third metallized ring 216.

[0029] The solder ball 230 is disposed on the third solder pad 215.

[0030] The three-dimensional stacked infrared detector structure provided in this embodiment of the invention uses a ceramic adapter ring 210 to achieve three-dimensional stacked vacuum packaging and electrical interconnection, which greatly reduces the overall packaging volume and overcomes the shortcomings of traditional metal and ceramic packaging with large size.

[0031] The infrared detector chip 200 is a detection unit of a three-dimensional stacked infrared detector. For example... Figure 8 As shown, it is a top view schematic diagram of an infrared detector chip 200 with a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention. The infrared detector chip 200 includes a substrate 204 and an infrared sensing array region 201, a first pad region and a first metallization ring 203 disposed on the surface of the substrate 204.

[0032] The substrate 204 contains a readout circuit (not shown in the attached drawings). The readout circuit is electrically connected to the infrared sensing array area 201, and can collect, amplify and preprocess the electrical signals generated by the infrared sensing array area 201, and then transmit the processed electrical signals to the first pad area, thereby completing the reading and relay of the detection signal and ensuring stable signal output.

[0033] The infrared sensing array area 201 is disposed on the surface of the substrate 204. It is composed of a large number of photosensitive pixel units and is the core functional area for the infrared detector chip 200 to realize infrared detection. This area can receive infrared radiation incident from the outside and convert the infrared light signal into a corresponding analog electrical signal. The generated electrical signal is synchronously transmitted to the readout circuit inside the substrate 204 to complete subsequent signal acquisition and processing.

[0034] The first pad area includes a plurality of first pads 202. The plurality of first pads 202 are electrically connected to the readout circuit inside the substrate 204 to receive the electrical signal processed by the readout circuit and transmit the electrical signal outward to the second pad 213 of the ceramic adapter ring 210, thereby realizing the electrical connection between the infrared detector chip 200 and the ceramic adapter ring 210.

[0035] Compared to the traditional packaging layout where the pads of the infrared detector chip 200 are confined to the edge of the chip to accommodate wire bonding, in this embodiment of the invention, the pads (i.e., the first pads 202) of the infrared detector chip 200 can be flexibly arranged in the blank areas of the internal wiring of the chip, and their position is not limited by the edge. This distribution of the first pads 202 can not only effectively reduce the overall size of the infrared detector chip 200, but also shorten the internal wiring length from the pads to the functional areas, thereby reducing wiring resistance and reducing signal interference caused by parasitic capacitance, thus improving signal transmission quality.

[0036] For example, in one embodiment, a plurality of the first pads 202 are all disposed on the same side of the infrared sensing array region 201. Specifically, as Figure 8As shown, multiple first pads 202 are disposed above the infrared sensing array area 201 to facilitate precise alignment and welding of the second pads 213 corresponding to the ceramic adapter ring 210.

[0037] For example, in another embodiment, a plurality of the first pads 202 are respectively disposed on different sides of the infrared sensing array region 201. Specifically, as Figure 9 The diagram shown is another top view of an infrared detector chip 200 with a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention. Multiple first pads 202 are respectively disposed on different sides of the infrared sensing array region 201. In this embodiment, the pad positions can be flexibly allocated according to the number of signals and circuit planning requirements, effectively distributing wiring pressure.

[0038] The first metallization ring 203 surrounds the infrared sensing array area 201 and the first pad area, meaning that the infrared sensing array area 201 and the first pad area are located within the area surrounded by the first metallization ring 203. Specifically, the first metallization ring 203 has a ring structure that completely surrounds the infrared sensing array area 201 and the first pad area, so that the infrared sensing array area 201 and the first pad area are entirely within the enclosure of the first metallization ring 203. On the one hand, the first metallization ring 203 can achieve hermetically sealed welding with the second metallization ring 214 on the ceramic adapter ring 210 to form a sealed cavity, providing a vacuum sealing environment for the infrared sensing array area 201; on the other hand, it can define the boundary of the sealed area, preventing external moisture and dust from intruding, while also improving the structural strength and packaging reliability of the three-dimensional stacked infrared detector in conjunction with the overall structure.

[0039] In one embodiment, the first metallization ring 203 is a metal ring fabricated on the substrate 204 for welding to the ceramic adapter plate. The material of the first metallization ring 203 may be Ti / Ni / Au, Cr / Ni / Au, Ti / Pt / Au, Ti / Pt / Au, or Ti / Au, and these materials are formed on the surface of the substrate 204 by sputtering or evaporation processes.

[0040] The ceramic adapter ring 210 is disposed on the infrared detector chip 200 to realize signal transfer, mechanical stacking and hermetic sealing. On the one hand, it leads the electrical signal of the infrared detector chip 200 from the first pad 202 to the third pad 215 through the internal conductive line 217, completing the transfer and output of electrical signals. On the other hand, it is sealed with the first metallized ring 203 to form a vacuum cavity, while supporting the window 220 and constructing a complete three-dimensional stacked packaging structure.

[0041] like Figures 2-7 , Figure 10 and Figure 11 As shown, where, Figure 10 This is a bottom view schematic diagram of the ceramic adapter ring 210 of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention. Figure 11 This is a top view schematic diagram of a ceramic adapter ring 210 of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention. The ceramic adapter ring 210 includes a window 211 and an annular body 212 disposed around the periphery of the window 211. The annular body 212 is arranged around the window 211 in a complete circle, and the two are an integral structure with an overall hollow annular shape. In some embodiments, the main material of the annular body 212 may be Al2O3 ceramic material, AlN ceramic material, etc.

[0042] The window 211 corresponds to the infrared sensing array area 201. Specifically, the window 211 is directly aligned with the infrared sensing array area 201 of the infrared detector chip 200 below, allowing external infrared radiation to pass through the window 211 and enter the infrared sensing array area 201 without obstruction. This effectively avoids problems such as light path obstruction and light deflection, ensuring that the infrared sensing array area 201 can fully receive infrared signals and guaranteeing the effectiveness and accuracy of infrared detection.

[0043] The annular body 212 serves as a load-bearing and connecting substrate, arranging various solder pads and metallized structures to achieve electrical connection and hermetically sealed assembly. In some embodiments, the annular body 212 is an annular ceramic body with internal wiring.

[0044] The lower surface of the annular body 212 includes a second pad area disposed around the window 211 and a second metallization ring 214 surrounding the window 211 and the second pad area.

[0045] The second pad area includes multiple second pads 213, each of which is aligned and soldered to the corresponding first pad 202 on the infrared detector chip 200. This achieves electrical connection between the infrared detector chip 200 and the ceramic adapter ring 210, ensuring stable transmission of detection signals. In some embodiments, the second pads 213 and the first pads 202 are positioned one-to-one and precisely aligned in the vertical direction. This minimizes the connection distance between the pads, reducing the difficulty of the soldering process, ensuring uniform solder filling of the mating surface, improving the solder joint strength and contact stability, effectively avoiding defects such as cold solder joints and misaligned solder joints, and further guaranteeing the long-term reliability of the electrical connection between the infrared detector chip 200 and the ceramic adapter ring 210.

[0046] The second metallized ring 214 and the first metallized ring 203 are fused together by the first solder ring 260, forming an annular sealing barrier that completely encloses the infrared sensing array area 201 and the first pad area inside the cavity. The connection structure between the second metallized ring 214 and the first metallized ring 203 ensures the stability of the electrical connection and creates a sealed vacuum cavity, effectively isolating external moisture, dust, and air interference. Simultaneously, the first pad 202 of the infrared detector chip 200 is located within the sealed cavity, abandoning the traditional wire bonding structure, thereby increasing the overall volume of the sealed cavity and extending the vacuum life of the encapsulation.

[0047] In one embodiment, the second metallization ring 214 is a metal ring fabricated on the annular body 212, used for soldering to the first metallization ring 203 of the infrared detector chip 200 via a first solder ring 260. The material of the second metallization ring 214 can be Ti / Pt / Au, Cr / Ni / Au, or Cu, etc., which are formed on the lower surface of the annular body 212 by thin film methods (DPC, PVD), thick film methods (TFC), or direct copper plating (DBC). The solder of the first solder ring 260 is AuSn (80Au20Sn), AuSi, Ag paste, AgCu, Al-Ge eutectic, or glass paste (low-temperature glass), etc.

[0048] The upper surface of the annular body 212 includes a third pad area disposed around the window 211 and a third metallized ring 216 disposed at the edge of the window 211.

[0049] The third pad area includes multiple third pads 215. The second pad 213 is electrically connected to the third pad 215 through conductive lines 217 disposed within the annular body 212, so as to transfer the electrical signal output by the infrared detector chip 200 from the lower layer to the upper surface of the ceramic adapter ring 210. Furthermore, the spacing between two adjacent third pads 215 is greater than the spacing between two adjacent first pads 202, effectively solving the interconnection problem caused by the small size and dense arrangement of the original infrared detector chip 200 pads. It eliminates the need for fragile wire bonding technology for signal extraction, simplifying the assembly process, completely avoiding the problems of easily broken metal leads and the need for additional protective structures, and also adapting to ball-mounting technology to achieve direct interconnection with external circuits, significantly improving the reliability of electrical connections. Simultaneously, it further optimizes the overall structural layout, contributing to the miniaturization of the device.

[0050] Conductive lines 217 are disposed within the annular body 212. These conductive lines 217 are arranged vertically or horizontally, with their two ends connected to the second pad 213 and the third pad 215 respectively, forming a vertically continuous signal transmission channel. The conductive lines 217 are integrated inside the annular body 212, not occupying external space, which helps to simplify the overall structure and promote device miniaturization. Simultaneously, relying on the excellent insulation properties of the ceramic substrate, each conductive line 217 is isolated from the others, effectively preventing signal crosstalk. By using the conductive lines 217 to complete signal transfer, stable transmission of electrical signals from the densely arranged first pads 202 at the lower level to the widely spaced third pads 215 at the upper level is achieved, replacing the traditional wire bonding scheme and improving signal transmission efficiency and the robustness of the connection structure.

[0051] In one embodiment, the infrared detector chip 200, the main body 212, the first metallized ring 203, the second metallized ring 214, and the first solder ring 260 have the same outer diameter, meaning that the length and width of the infrared detector chip 200, the main body 212, the first metallized ring 203, the second metallized ring 214, and the first solder ring 260 are all the same. After assembly, their edges are flush with each other, resulting in a neat and uniform overall shape. This facilitates positioning during the packaging process, simplifies the three-dimensional stacking assembly process, reduces the risk of alignment deviation, and makes the overall device structure more compact, fully meeting the design requirements of miniaturized packaging. In some embodiments, for the 8~14μm working band, the thickness of the ceramic adapter ring 210 is greater than or equal to 0.6mm. In practical applications, the thickness parameter can be flexibly adjusted according to imaging effects, working band, and other conditions.

[0052] like Figures 2-7 , Figure 12 and Figure 13 As shown, where Figure 12 This is a top view schematic diagram of the window 220 of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention. Figure 13 This is a bottom view of the window 220 of a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention. The window 220 covers the window 211, providing comprehensive shielding protection against external dust, moisture, particulate matter, and mechanical forces from entering the sealed cavity and protecting the infrared sensing array area 201 and other structures within the cavity from damage. Furthermore, it possesses excellent infrared transmittance, allowing infrared radiation to penetrate and incident on the infrared sensing array area 201 without significant loss, ensuring normal reception of the detection signal. In some embodiments, the window 220 can be made of materials such as Ge, Si, ZnSe, ZnS, or composite materials composed of these materials.

[0053] The window 220 and the third metallized ring 216 are welded together by a second solder ring 270, thereby fixing the window 220 and further enhancing the sealing effect of the overall cavity, maintaining the vacuum environment inside the cavity, and ensuring the long-term stable operation of the infrared detector chip 200. In some embodiments, the edge of the window 220 facing the ceramic adapter ring 210 has a fourth metallized ring 223, which is welded to the third metallized ring 216 by a second solder ring 270, thereby fixing the window 220. In some embodiments, the material of the fourth metallized ring 223 can be Ti / Ni / Au, Cr / Ni / Au, Ti / Pt / Au, Ti / Pt / Au, Ti / Au, etc., which are formed on the surface of the window 220 by sputtering or evaporation processes.

[0054] In some embodiments, the side of the window 220 facing the infrared detector chip 200 is coated with a first antireflection film 221, and the side of the window 220 facing away from the infrared detector chip 200 is coated with a second antireflection film 222 to enhance infrared transmittance. Depending on the material of the window 220, the coating material can be Y2O3, ZnS, TiO2, MgF2, YF3, or a composite film layer composed of these.

[0055] In some embodiments, the upper surface of the annular body 212 further includes a stepped region 2121 disposed at the edge of the window 211. The stepped region 2121 extends toward the infrared detector chip 200, and the third metallization ring 216 is disposed on the stepped surface of the stepped region 2121. The window 220 is located within the area surrounded by the stepped region 2121. The stepped region 2121 can accommodate the window 220, thereby reducing the overall thickness of the three-dimensional stacked infrared detector structure. Furthermore, the stepped region 2121 can block solder during the soldering process, preventing solder overflow from contaminating other areas of the device. It can also provide circumferential protection for the window 220, reducing damage to the window 220 caused by external impacts and compression, and further improving the overall reliability of the packaging structure.

[0056] In some embodiments, the upper surface of the window 220 is lower than the upper surface of the annular body 212, or the upper surface of the window 220 is flush with the upper surface of the annular body 212, further enabling the window 220 to be fully embedded inside the stepped area 2121. The outer dimensions of the window 220 are slightly smaller than the outer diameter of the window 211 of the ceramic adapter ring 210, and its thickness is also lower than the overall thickness of the ceramic adapter ring 210. After assembly, it will not protrude outward, further effectively controlling the overall packaging outline and avoiding additional structural dimensions.

[0057] In a three-dimensional stacked infrared detector structure provided in an embodiment of the present invention, the ceramic adapter ring 210 can increase the distance between the window 220 and the focal plane of the infrared detector chip 200, effectively reducing the interference of minute defects and attached impurities on the surface of the window 220 on the infrared imaging quality.

[0058] The solder balls 230 serve as external electrical connection terminals, positioned on the third pad 215, to enable electrical connection between the three-dimensional stacked infrared detector of this invention and external circuitry, thus facilitating the output of the detection signal. The use of solder balls 230 for interconnection adapts to the large-pitch layout of the third pad 215, simplifying the assembly process and ensuring strong connection stability. It also further avoids the problems of easy wire breakage and the need for additional protection associated with traditional wire bonding, and facilitates device miniaturization and integrated packaging.

[0059] In some embodiments, the lower surface of the annular body 212 further includes a getter attachment region 218 located within the area surrounded by the second metallized ring 214; the three-dimensional stacked infrared detector structure further includes a getter 240, which is disposed in the getter attachment region 218. The getter 240 is located within the sealed cavity and can continuously adsorb trace amounts of gas, water vapor, and volatile substances remaining inside the cavity, maintaining a high vacuum environment within the cavity for a long time, preventing gas molecules and water vapor from affecting infrared detection performance, and simultaneously delaying oxidation and aging of internal components, effectively extending the overall service life of the three-dimensional stacked infrared detector, and further improving the long-term stability and operational reliability of the packaging structure.

[0060] In some embodiments, the getter attachment area 218 and the second pad area are located on the same side of the window 211 to fully utilize the empty area of ​​the annular body 212, rationally plan the internal space of the cavity, and avoid interference between functional areas; at the same time, the getter 240 is placed within the effective space of the sealed cavity, which can uniformly adsorb residual gas and water vapor in various parts of the cavity, ensuring the consistency of the overall vacuum environment. In some embodiments, the position of the second pad area follows that of the first pad, so the getter attachment area 218 and the second pad area can also be located on different sides of the window 211.

[0061] The getter 240 can be activated by either high-temperature activation or electro-activation. High-temperature activation can be performed simultaneously with the high-temperature process in the packaging process, without the need for additional circuitry.

[0062] In some embodiments, the upper surface of the annular body 212 further includes a getter electroactivation point 219, which is electrically connected to the getter 240 via a conductive line 217 disposed within the annular body 212. External control signals can be transmitted to the getter 240 via the getter electroactivation point 219 and the conductive line 217 passing through the annular body 212, thereby enabling remote electroactivation of the getter 240. This structure allows activation without disassembling the packaging structure, providing flexible activation timing. It allows for pre-processing before device shipment and reactivation during use based on changes in cavity vacuum, continuously ensuring getter efficiency and effectively extending the overall service life of the device. Furthermore, the conductive line 217 for electrical connection is integrated within the annular body 212, with a neat layout that does not occupy effective internal space and avoids problems such as short circuits and aging caused by exposed wiring.

[0063] In some embodiments, the getter electroactivation point 219 and the third pad area are located on the same side of the window 211, thereby allowing for centralized planning of functional points on the device surface, making full use of the available space of the annular body 212, and resulting in a more orderly and systematic circuit layout. Simultaneously, the proximity of the electroactivation point and signal pads facilitates unified wiring and connection of external circuits, simplifying subsequent assembly and wiring processes. In some embodiments, the getter electroactivation point 219 can also be arranged at any position on the upper surface of the annular body 212.

[0064] In some embodiments, the three-dimensional stacked infrared detector structure further includes a breathable barrier structure 250, which is disposed between the getter attachment area 218 and the infrared sensing array area 201 to block particles falling from the getter 240. The breathable barrier structure 250 is breathable and can block getter debris falling from the getter attachment area 218, preventing debris from rolling onto the infrared sensing array area 201 and affecting the infrared detector imaging. In some embodiments, the breathable barrier structure 250 is a porous mesh structure made of metal. In some embodiments, the porous mesh structure can be pre-welded onto the annular body 212. The porous mesh structure has a certain degree of toughness, and its lower end contacts the surface of the infrared detector chip 200. The pores on the surface of the porous mesh structure allow gas to flow freely, thereby blocking getter debris without affecting the getter's absorption performance.

[0065] The three-dimensional stacked infrared detector structure provided by the embodiments of the present invention can reduce the overall volume of the infrared detector structure, eliminate the fragile wire bonding structure and simplify the protection design, get rid of the interconnection limitations caused by the small-sized pads of the detector chip, and at the same time increase the volume of the sealed cavity and extend the service life of the packaged vacuum.

[0066] As an example, the present invention also provides a method for manufacturing the above-described three-dimensional stacked infrared detector structure. The manufacturing method includes: a. placing the infrared detector chip 200 on a tooling fixture; b. placing a pre-fabricated first solder ring 260 on the first metallized ring 203 of the infrared detector chip 200; c. placing a ceramic adapter ring 210 with a pre-fabricated getter 240 and a gas-permeable barrier structure 250 on top of the first solder ring 260; d. placing a pre-fabricated second solder ring 270 on a third metallized ring 216 above the ceramic adapter ring 210; e. placing a window 220 on top of the pre-fabricated second solder ring 270; f. reflow soldering; g. attaching solder balls to the third pad 215 of the ceramic adapter ring 210; h. placing the package with attached solder balls into a reflow oven for reflow, so that the solder balls 230 are firmly soldered to the third pad 215 of the ceramic adapter ring 210, and cleaning and inspecting the quality of the solder balls 230 after reflow; i. activating the getter 240.

[0067] In addition to the examples above, the present invention can also fabricate getter 240 on window 220, or solder can be fabricated on infrared detector chip 200 and window 220 respectively, to simplify the process or further reduce the package size, which will not be elaborated here.

[0068] It should be noted that references to "an embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," etc., in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but each embodiment may not necessarily include that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. In addition, when a specific feature, structure, or characteristic is described in connection with an embodiment, whether explicitly described or not, implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the knowledge of those skilled in the art.

[0069] It should be noted that the terms "comprising" and "having," and their variations, used in this invention document are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, unless explicitly indicated by the context. It should be understood that such data used interchangeably where appropriate. Furthermore, embodiments and features within embodiments of this invention can be combined with each other unless otherwise specified. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this invention. In the various embodiments described above, each embodiment focuses on its differences from other embodiments; similar or identical parts between embodiments can be referred to interchangeably.

[0070] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A three-dimensional stacked infrared detector structure, characterized in that, include: An infrared detector chip includes an infrared sensing array area, a first pad area disposed around the infrared sensing array area, and a first metallization ring surrounding the infrared sensing array area and the first pad area. The first pad area includes a plurality of first pads. A ceramic adapter ring, disposed on the infrared detector chip, includes a window and an annular body disposed around the window. The window corresponds to the infrared sensing array area. The lower surface of the annular body includes a second pad area disposed around the window and a second metallized ring surrounding the window and the second pad area. The second pad area includes multiple second pads. The second pads are soldered to the first pads, and the second metallized ring is soldered to the first metallized ring. The upper surface of the annular body includes a third pad area disposed around the window and a third metallized ring disposed at the edge of the window. The third pad area includes multiple third pads. The second pads are electrically connected to the third pads through conductive lines disposed within the annular body. The spacing between two adjacent third pads is greater than the spacing between two adjacent first pads. A window slat, covering the window, and welded to the third metallized ring; Solder balls are placed on the third solder pad.

2. The three-dimensional stacked infrared detector structure according to claim 1, characterized in that, The first pads are all located on the same side of the infrared sensing array area, or the first pads are respectively located on different sides of the infrared sensing array area.

3. The three-dimensional stacked infrared detector structure according to claim 1, characterized in that, The upper surface of the annular body also includes a stepped area disposed at the edge of the window, the stepped area extending toward the infrared detector chip, the third metallized ring disposed on the stepped surface of the stepped area, and the window plate located within the area surrounded by the stepped area.

4. The three-dimensional stacked infrared detector structure according to claim 3, characterized in that, The upper surface of the window is lower than the upper surface of the annular body, or the upper surface of the window is flush with the upper surface of the annular body.

5. The three-dimensional stacked infrared detector structure according to claim 1, characterized in that, The lower surface of the annular body also includes a getter attachment area located within the area surrounded by the second metallized ring; the three-dimensional stacked infrared detector structure also includes a getter, which is disposed in the getter attachment area.

6. The three-dimensional stacked infrared detector structure according to claim 5, characterized in that, The getter adhesion area and the second pad area are located on the same side of the window.

7. The three-dimensional stacked infrared detector structure according to claim 5, characterized in that, The upper surface of the annular body also includes getter electroactivation points, which are electrically connected to the getter through conductive lines passing through the annular body.

8. The three-dimensional stacked infrared detector structure according to claim 5, characterized in that, The getter electroactivation point and the third pad area are located on the same side of the window.

9. The three-dimensional stacked infrared detector structure according to claim 5, characterized in that, The three-dimensional stacked infrared detector structure also includes a breathable barrier structure, which is disposed between the getter attachment area and the infrared sensing array area to block particulate matter from falling off the getter.

10. The three-dimensional stacked infrared detector structure according to claim 1, characterized in that, The infrared detector chip, the main body, the first metallized ring, and the second metallized ring have the same outer diameter.

11. The three-dimensional stacked infrared detector structure according to claim 1, characterized in that, The thickness of the ceramic adapter ring is greater than or equal to 0.6 mm.

12. A method for manufacturing a three-dimensional stacked infrared detector structure according to any one of claims 1 to 11, characterized in that, Includes the following steps: Place the infrared detector chip on the tooling fixture; The pre-fabricated first solder ring is placed on the first metallization ring of the infrared detector chip; The ceramic adapter ring, with the getter and air-permeable barrier structure prepared, is placed above the first solder ring; The prefabricated second solder ring is placed on the third metallized ring above the ceramic adapter ring; Place the window above the second solder ring; Reflow soldering; Balls are implanted on the prefabricated third pad of the ceramic adapter ring; The package with the solder balls attached is placed in a reflow oven for reflow, so that the solder balls are soldered onto the third pad of the ceramic adapter ring. Activate the inhaler.

Images