An infrared chip packaging device

Abstract

The utility model relates to infrared device field relates to disclose a kind of infrared chip packaging devices, including the infrared chip of upper surface formation has infrared photosensitive unit;Support frame board is set on the upper surface of infrared chip, and the light transmission via hole of corresponding infrared photosensitive unit is opened;Infrared light transmission sheet is set on support frame board and covers light transmission via hole;Wherein, light transmission via hole at least one side hole wall is the stepped hole wall structure with stepped surface;The stepped surface of stepped hole wall structure is lower than the edge upper surface of light transmission via hole;Step surface on the stepped hole wall structure is covered and is provided with getter;Support frame board is also provided with and the activation electrode of getter connection.This application breaks through the limitation of getter area size to chip device miniaturization, ensures that getter has enough adsorption area, and further ensures that the vacuum cavity where infrared photosensitive unit is located has good gettering effect, so as to ensure the good working performance of device.

Description

Technical Field

[0001] This utility model relates to the field of infrared detection device technology, and in particular to an infrared chip packaging device. Background Technology

[0002] Uncooled infrared detectors, with their advantages of wide spectral response and no need for cryogenic cooling, have been widely used in security monitoring, automotive night vision, industrial inspection, and consumer electronics. Silicon-based or germanium-based wafer-level packaging (WLP) infrared detectors utilize a wafer-level bonding vacuum seal between the infrared transmission window and the chip substrate via a ring frame. This overcomes the size limitations and cost bottlenecks of traditional infrared detector packaging technologies, enabling miniaturization of infrared detectors. However, the small size and compact structure of wafer-level packaged infrared detectors also limit the layout of components such as getters within the device's vacuum cavity. Utility Model Content

[0003] The purpose of this invention is to provide an infrared chip packaging device that, while ensuring miniaturization, prevents interference between the circuitry and getter on the infrared chip, and provides a sufficiently large getter area to ensure good device performance.

[0004] To solve the above-mentioned technical problems, this utility model provides an infrared chip packaging device, comprising:

[0005] An infrared chip with infrared photosensitive units formed on its upper surface;

[0006] A support frame plate with a light-transmitting hole is disposed on the upper surface of the infrared chip, corresponding to the infrared photosensitive unit.

[0007] An infrared light-transmitting sheet is disposed on the support frame plate and covers the light-transmitting holes;

[0008] Wherein, at least one side of the light-transmitting hole is a stepped hole wall structure with a stepped surface; the stepped surface of the stepped hole wall structure is lower than the upper edge surface of the light-transmitting hole; a getter is covered on the stepped surface of the stepped hole wall structure; and an activation electrode connected to the getter is also provided on the support frame plate.

[0009] In one optional embodiment of this application, the support frame plate includes an extension portion extending outward from the outside of the light-transmitting through hole; the activation electrode extends along the interior of the support frame plate from the stepped surface of the stepped hole wall structure to the upper surface of the extension portion.

[0010] In one optional embodiment of this application, the end face diameter of the activation electrode on the support frame plate is not less than 1 mm.

[0011] In one optional embodiment of this application, the stepped hole wall structure is a multi-layer stepped structure; the getter has a stepped surface structure.

[0012] The extension portion and the stepped hole wall structure are located on the same side of the light-transmitting hole.

[0013] In one optional embodiment of this application, the stepped hole wall structure is a single-layer stepped structure; and the three side walls adjacent to the light-transmitting hole are all the stepped hole wall structure.

[0014] The getter is a U-shaped structure arranged along the stepped surface of the stepped hole wall structure on three sides;

[0015] The extension portion and the side of the light-transmitting hole where the stepped hole wall structure is not provided.

[0016] In an optional embodiment of this application, a shielding strip is further provided on the edge of the stepped hole wall structure near the center of the light-transmitting hole; the upper surface of the shielding strip is higher than the upper surface of the stepped hole wall structure but not higher than the edge upper surface of the light-transmitting hole.

[0017] In an optional embodiment of this application, the infrared photosensitive unit further includes a reference infrared photosensitive unit located below the stepped hole wall structure.

[0018] In one optional embodiment of this application, the thickness of the support frame plate is 0.5mm to 0.7mm.

[0019] In one optional embodiment of this application, the supporting frame plate is a multilayer ceramic plate structure formed by one or more ceramic plates selected from alumina ceramic plates, aluminum nitride ceramic plates, and beryllium oxide ceramic plates.

[0020] In one optional embodiment of this application, the infrared light-transmitting sheet is a germanium wafer light-transmitting sheet, a silicon wafer light-transmitting sheet, or a sulfur-selenium glass light-transmitting sheet.

[0021] In one optional embodiment of this application, the surface of the infrared light-transmitting sheet is provided with a magnesium fluoride coating layer, a zinc sulfide coating layer, or a metasurface structure.

[0022] The present invention provides an infrared chip packaging device, comprising an infrared chip with an infrared photosensitive unit formed on its upper surface; a support frame plate disposed on the upper surface of the infrared chip and having a light-transmitting hole corresponding to the infrared photosensitive unit; an infrared light-transmitting sheet disposed on the support frame plate and covering the light-transmitting hole; wherein, at least one side of the light-transmitting hole has a stepped hole wall structure with a stepped surface; the stepped surface of the stepped hole wall structure is lower than the edge upper surface of the light-transmitting hole; a getter is disposed on the stepped surface of the stepped hole wall structure; and an activation electrode connected to the getter is also disposed on the support frame plate.

[0023] This application, on a support frame plate supporting the infrared light-transmitting sheet and the infrared chip, sets at least one side of the light-transmitting hole wall as a stepped hole wall structure to support the getter. In other words, the getter is placed on the support frame plate, and the stepped hole wall structure, extending into the light-transmitting hole, creates a stepped surface, increasing the hole wall area on at least one side of the light-transmitting hole to support the getter. This allows the getter area to be larger without being limited by the height of the support frame. Therefore, this application overcomes the limitation on getter area size imposed by chip miniaturization, ensuring the getter has a sufficiently large adsorption area, thereby ensuring good gettering effect on the vacuum cavity where the infrared photosensitive unit is located, and thus ensuring good device performance. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the infrared chip packaging device provided in the embodiments of this application;

[0026] Figure 2 For along Figure 1 Schematic diagram of the cross-sectional structure along the AA direction;

[0027] Figure 3 This is an exploded view of the infrared chip packaging device provided in the embodiments of this application;

[0028] Figure 4 The following are provided for the embodiments of this application: Figure 1 Schematic diagram of the first type of cross-sectional structure in the BB direction;

[0029] Figure 5 The following are provided for the embodiments of this application: Figure 1 Schematic diagram of the second type of cross-sectional structure in the BB direction;

[0030] Figure 6 The following are provided for the embodiments of this application: Figure 1 Schematic diagram of the third cross-sectional structure in the BB direction;

[0031] Figure 7 A top view of the supporting frame plate provided in an embodiment of this application;

[0032] Figure 8A schematic diagram of a support frame plate provided in an embodiment of this application;

[0033] In the attached diagram: 1 is the infrared chip, 11 is the infrared photosensitive unit, 110 is the reference infrared photosensitive unit, 2 is the support frame plate, 200 is the light-transmitting hole, 20 is the activation electrode, 201 is the electrode sheet, 21 is the epitaxial part, 22 is the stepped hole wall structure, 23 is the shielding strip, 3 is the infrared light-transmitting sheet, 4 is the getter, and 5 is the bonding layer. Detailed Implementation

[0034] The core of this invention is to provide an infrared chip packaging device that avoids the limitation on the getter area size caused by chip miniaturization, ensuring good gas intake effect in the vacuum cavity where the infrared photosensitive unit is located, thereby ensuring good working performance of the device.

[0035] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. 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.

[0036] like Figures 1 to 3 As shown, Figure 1 This is a schematic diagram of the structure of the infrared chip packaging device provided in the embodiments of this application; Figure 2 For along Figure 1 Schematic diagram of the cross-sectional structure along the AA direction; Figure 3 This is an exploded view of the infrared chip packaging device provided in an embodiment of this application.

[0037] In one specific embodiment of this application, the infrared chip packaging device may include:

[0038] An infrared chip 1 with an infrared photosensitive unit 11 formed on its upper surface;

[0039] A support frame plate 2 with a light-transmitting hole 200 is provided on the upper surface of the infrared chip 1, corresponding to the infrared photosensitive unit 11.

[0040] An infrared light-transmitting sheet 3 is set on the support frame plate 2 and covers the light-transmitting holes 200;

[0041] Among them, at least one side of the light-transmitting through hole 200 is a stepped hole wall structure 22 with a stepped surface; the stepped surface of the stepped hole wall structure 22 is lower than the upper edge surface of the light-transmitting through hole 200; a getter 4 is covered on the stepped surface of the stepped hole wall structure 22; an activation electrode 20 connected to the getter 4 is also provided on the support frame plate 2.

[0042] like Figure 2 and Figure 3 As shown, the infrared chip 1 in this embodiment includes a chip substrate, a plurality of infrared photosensitive units 11 arranged in a two-dimensional array on the chip substrate, and a readout circuit structure electrically connected to the infrared photosensitive units 11. Its specific structure and fabrication method are similar to those of a conventional infrared chip 1, and will not be discussed in detail in this embodiment. The difference is that the area where the infrared photosensitive units 11 are distributed on the infrared chip 1, that is, the photosensitive area, is not located at the exact center of the infrared chip 1, but closer to one side of the infrared chip 1, thereby allowing a larger space area to be reserved on the opposite side of the infrared chip 1.

[0043] Furthermore, in this embodiment, the upper surfaces of the support frame plate 2 and the infrared chip 1 (i.e., the surface where the infrared photosensitive unit 11 is located) are bonded together, and at least a light-transmitting hole 200 is provided at the position corresponding to the photosensitive area. That is to say, the light-transmitting hole 200 provided on the support frame plate 2 in this embodiment is at least not smaller than the area where the infrared photosensitive unit 11 is distributed.

[0044] The infrared transparent sheet 3 is a thin sheet structure capable of transmitting infrared light. It can be fabricated using materials with high transmittance in the infrared band, such as germanium (Ge) wafers, silicon (Si) wafers, or sulfur selenium glass, which can effectively transmit infrared radiation. In practical applications, the wafer can be thinned first, and then an infrared antireflective coating, such as a magnesium fluoride coating or a zinc sulfide coating, can be deposited. After deposition, the wafer is diced to obtain an infrared transparent sheet 3 with good optical performance. Optionally, during the fabrication of the infrared transparent sheet 3, after thinning the wafer, a metasurface structure (increasing the transmittance of infrared light) can be created on the wafer surface using photolithography-etching. After removing the resist, the wafer is diced to obtain an infrared transparent sheet 3 with even higher optical performance.

[0045] Obviously, the main purpose of the infrared light-transmitting sheet 3 in this embodiment is to form a vacuum cavity in the light-transmitting hole 200 together with the supporting frame plate 2 and the infrared chip 1 to accommodate the infrared photosensitive unit 11. The vacuum degree of the vacuum cavity is not less than 1 Pa. Therefore, the infrared light-transmitting sheet 3 in this embodiment should be a thin sheet structure with a shape roughly similar to the light-transmitting hole 200 on the supporting frame plate 2, but slightly larger in size. This allows the edge of the infrared light-transmitting sheet 3 to be sealed and bonded to the edge of the light-transmitting hole 200 on the supporting frame plate 2. In short, it is sufficient to ensure that the infrared light-transmitting sheet 3 can seal the light-transmitting hole 200 from the upper end (i.e., the end away from the infrared chip 1).

[0046] In addition, the support frame plate 2 in this embodiment can be a multilayer ceramic structure formed by any one or more ceramics such as alumina, aluminum nitride, and beryllium oxide; the thickness of the support frame plate 2 can be approximately 0.6mm to 0.7mm, which is roughly equivalent to the thickness of the infrared chip 1 and the infrared light-transmitting sheet 3, thereby ensuring that the thickness of the entire infrared chip 1 package device is less than 3mm, thus realizing the miniaturization of the infrared chip 1 package device.

[0047] like Figure 3 As shown, the infrared light-transmitting sheet 3 and the supporting frame plate 2, as well as the supporting frame plate 2 and the infrared chip 1, can be sealed and connected by eutectic welding of the bonding layer 5 or by bonding with conductive adhesive, thereby achieving a sealed connection between the infrared light-transmitting sheet 3, the supporting frame plate 2 and the infrared chip 1 stacked sequentially.

[0048] It is understandable that during the bonding process between the infrared light-transmitting sheet 3 and the infrared chip 1, it is susceptible to contamination by microparticles, which can form optical scattering centers and cause a decrease in the signal-to-noise ratio of the device imaging. In this embodiment, based on the miniaturization of the device using wafer-level packaging (WLP) technology, the position of the infrared light-transmitting sheet 3 on the infrared chip is raised by the support frame plate 2. This increases the distance between foreign objects such as microparticles and the infrared photosensitive pixel 11, thereby reducing the degree of influence on the infrared photosensitive pixel and increasing the signal-to-noise ratio of the device.

[0049] Based on this, such as Figures 3 to 5 As shown, at least one side of the light-transmitting through-hole 200 has a stepped hole wall structure 22. Compared with the vertical plane hole wall surface, the stepped surface of the stepped hole wall structure 22 can obviously provide a larger bearing surface for the getter 4. Thus, by covering the stepped surface of the stepped hole wall structure 22 with the getter 4, a larger area of ​​getter 4 can be provided without being limited by the height of the supporting frame plate 2, thereby effectively ensuring the getter 4's gas absorption effect inside the vacuum cavity of the device.

[0050] It is understandable that the stepped surface of the stepped hole wall structure 22 is lower than the upper edge surface of the light-transmitting hole 200. That is to say, there is a gap between the stepped surface of the stepped hole wall structure 22 and the lower surface of the infrared light-transmitting sheet 3. The getter 4 is placed on the stepped surface of the stepped hole wall structure 22. Obviously, the upper surface of the getter 4 should not be higher than the upper edge surface of the light-transmitting hole 200. Thus, the getter 4 is located in the vacuum space inside the light-transmitting hole 200, thereby absorbing gas in the vacuum space where the infrared photosensitive unit 11 is located.

[0051] For example Figure 4 and Figure 5 As shown, the stepped hole wall structure 22 can be a single-layer stepped structure, such as... Figure 4As shown, the getter 4 can be a planar structure disposed on the horizontal step surface of the stepped hole wall structure 22; such as Figure 5 As shown, the getter 4 can also be an L-shaped getter that fits the horizontal and vertical step surfaces of the stepped hole wall structure 22.

[0052] Based on the above discussion, in another optional embodiment of this application, the support frame plate 2 may further include an extension portion 21 extending outward from the outside of the light-transmitting through hole 200; the activation electrode 20 extends along the interior of the support frame plate 2 from the stepped surface of the stepped hole wall structure 22 to the upper surface of the extension portion 21.

[0053] In this embodiment, the support frame plate 2, in addition to having an annular structure surrounding the light-transmitting hole 200, also has a portion of an extension 21 with a flat plate structure. That is to say, the light-transmitting hole 200 in this application is not located in the central region of the support frame plate 2, but is offset to one side, thus the support frame plate 2 has a generally asymmetrical U-shaped structure. Obviously, the direction in which the light-transmitting hole 200 is offset to one side on the support frame plate 2 is the same as the direction in which the photosensitive areas of each infrared photosensitive unit 11 are offset to one side on the infrared chip 1. Therefore, the extension 21 on the support frame plate 2 is also attached to the area on the infrared chip 1 that does not have an infrared photosensitive unit 11.

[0054] Based on this, one end of the activation electrode 20 of the activation agent 4 should be electrically connected to the getter 4, and the other end should extend out from the extension portion 21. Specifically, it can extend out from the side of the extension portion 21 or it can be exposed from the upper surface of the extension portion 21.

[0055] Taking the example where the end of the activation electrode 20 protrudes from the upper surface of the epitaxial portion 21, as follows: Figure 3 , Figure 4 and Figure 5 As shown, in an optional embodiment of this application, the support frame plate 2 has two internal through holes that extend from the stepped surface of the stepped hole wall structure 22 to the upper surface of the extension portion 21; each internal through hole is sealed and filled with an activation electrode 20; the two activation electrodes 20 are located at the ends of the stepped surface of the stepped hole wall structure 22 and are respectively in contact with the two ends of the getter 4.

[0056] Two electrode plates 201, respectively connected to both ends of the getter 4, can be provided on the stepped surface of the stepped hole wall structure 22; two internal through holes are provided on the support frame plate 2, extending from the stepped surface of the stepped hole wall structure 22 to the upper surface of the extension portion 21; two activation electrodes 20 extend from the stepped surface of the stepped hole wall structure 22 to the upper surface of the extension portion 21 through the two internal through holes; and the ends of the two activation electrodes 20 located on the stepped surface of the stepped hole wall structure 22 are respectively in contact with the two electrode plates 201.

[0057] like Figure 4 and Figure 5 As shown, the activation electrode 20 extends from the stepped surface of the stepped hole wall structure 22 to the upper surface of the extension portion 21, thus providing a conductive circuit for the getter 4 and the external power supply circuit. In practical applications, an internal through hole can be formed on the support frame plate 2 first, and then a conductive paste can be injected into the internal through hole. Once the conductive paste has solidified, the activation electrode 20 can be formed.

[0058] It is understandable that, because the upper surface area of ​​the epitaxial portion 21 is large enough, the end face of the activation electrode 20 exposed on the upper surface of the epitaxial portion 21 can be large enough. The aperture size of the activation electrode 20 on the upper surface of the epitaxial portion 21 can be no less than mm. For example, the end face can be a rectangular surface of 1 mm × 1.5 mm.

[0059] Therefore, in the actual process of energizing the getter 4 by activating the activation electrode 20, the conductive needle energizing the activation electrode 20 can have a larger contact area between the upper surface of the epitaxial portion 21 and the end face of the activation electrode 20, thereby ensuring the reliability of energizing the activation electrode 20 by the conductive needle. Especially when activating a large number of infrared chip 1 packaged devices at the same time in batches, the probability of the getter 4 being successfully activated can be guaranteed.

[0060] Based on the above discussion, such as Figure 6 As shown, in an optional embodiment of this application, the stepped hole wall structure 22 of the light-transmitting through hole 200 can be a multi-layer stepped structure; the getter 4 has a stepped surface structure; the extension portion 21 and the stepped hole wall structure 22 are located on the same side of the light-transmitting through hole 200.

[0061] like Figure 6 As shown, in this embodiment, the getter 4 simultaneously covers two horizontal directions and one vertical plane of the stepped hole wall structure 22, relative to... Figure 5 Regarding the stepped hole wall structure 22 shown, the dimension of the stepped hole wall structure 22 extending toward the center side of the light-transmitting through hole 200 in this embodiment can be smaller.

[0062] Furthermore, such as Figure 7 As shown, in an optional embodiment of this application, the stepped hole wall structure 22 of the light-transmitting hole 200 can be a single-layer stepped structure; and the three adjacent side holes of the light-transmitting hole are all stepped hole wall structures 22; the getter 4 is a U-shaped structure provided along the stepped surface of the three-sided stepped hole wall structure 22; the extension 21 is located on the side of the light-transmitting hole (200) where no stepped hole wall structure is provided.

[0063] like Figure 7As shown, in this embodiment, a single-layer stepped structure is provided on three sides of the light-transmitting hole 200. This allows the stepped hole wall structure 22 on each side to provide a bearing surface for the getter 4, enabling the getter 4 to be arranged around the infrared photosensitive unit 11. When the same area of ​​getter 4 needs to be provided, the dimension of the stepped hole wall structure 22 extending towards the center of the light-transmitting hole 200 on each side can be minimized in this embodiment, further reducing the space occupied by the stepped hole wall structure 22 inside the light-transmitting hole 200. Furthermore, the fact that the getter 4 is arranged around the infrared photosensitive unit 11 in this application further enhances the adsorption effect of the getter 4 on gases adsorbed from different directions.

[0064] Furthermore, considering that the heat generated by the getter 4 during the activation process of the activation electrode 20 may affect the infrared photosensitive unit 11, therefore, as Figure 8 As shown, the support frame plate 2 in this application may further include:

[0065] A shielding strip 23 is also provided on the edge of the stepped hole wall structure 22 near the center of the light-transmitting hole; the upper surface of the shielding strip 23 is higher than the stepped surface of the stepped hole wall structure 22 but not higher than the upper edge surface of the light-transmitting hole 200.

[0066] Reference Figure 8 The upper side of the shielding strip 23 may be flush with or slightly lower than the upper edge of the light-transmitting hole 200, while gaps are left between the two ends of the shielding strip 23 and the side walls adjacent to the stepped hole wall structure 22. Thus, the shielding strip 23, the stepped hole wall structure 22, and the hole wall of the light-transmitting hole 200 together form a concave space for the adsorbent 4. This concave space is also in air communication with the space where the infrared photosensitive unit 11 is located. In other words, the shielding strip 23 can, to a certain extent, shield the infrared photosensitive unit 11 from the heat generated when the getter 4 is activated by electricity, while ensuring the adsorption of gas within the space where the infrared photosensitive unit 11 is located by the getter 4. It is understood that the shielding strip 23 and the stepped hole wall structure 22 can be integrally formed.

[0067] Based on any of the above embodiments, in an optional embodiment of this application, the infrared chip 1 packaged device, the infrared photosensitive unit 11 further includes a reference infrared photosensitive unit 110 located below the stepped hole wall structure 22.

[0068] In this embodiment, the infrared photosensitive unit 11 on the infrared chip 1 may also include a portion of the infrared photosensitive units 11 serving as reference infrared photosensitive units 110, i.e., located within the dashed box on the infrared chip 1 in Figure 3. In practical applications, the reference infrared photosensitive unit 110 does not need to receive infrared light radiation, but rather serves as a reference for other units that can receive infrared light radiation. When determining the infrared signals generated by the infrared light sensed by other infrared photosensitive units 11, the output signal of the reference infrared photosensitive unit 110 can be used as a benchmark for calculation. This can, to a certain extent, eliminate noise caused by the inherent characteristics of the infrared photosensitive unit 11 itself and the chamber environment within the light-transmitting aperture 200, thereby improving the accuracy and reliability of the infrared data measured by the infrared photosensitive units 11 other than the reference infrared photosensitive unit 110.

[0069] Since the reference infrared photosensitive unit 110 does not need to receive infrared light, in this embodiment, the stepped hole wall structure 22 can be further set in the area of ​​the light-transmitting through hole 200 facing the reference infrared photosensitive unit 110. That is to say, in this embodiment, the stepped hole wall structure 22 serves both as a carrier of the getter 4 and as a light shield for the reference infrared photosensitive unit 110.

[0070] Obviously, in this embodiment, the shape and size of the light-transmitting hole 200 can be the same as the shape and size of the area covered by all infrared photosensitive units 11, while the stepped hole wall structure 22 is approximately the same as or the same as the shape and size of the area where the reference infrared photosensitive unit 110 is located.

[0071] In addition, the proportion of the reference infrared photosensitive unit 110 among all infrared photosensitive units 11 is generally relatively small. Therefore, if the size of the stepped hole wall structure 22 is only similar to the size of the area where the reference infrared photosensitive unit 110 is located, the stepped surface of the stepped hole wall structure 22 may not have enough space to carry the getter 4. Based on this, in practical applications, the area of ​​the light-transmitting through hole 200 can be slightly larger than the photosensitive area where the infrared photosensitive unit 11 is located, and the stepped hole wall structure 22 can be partially located directly above the reference infrared photosensitive unit 110, while the other part is directly opposite the area on the infrared chip 1 other than the photosensitive area (generally the area adjacent to the reference infrared photosensitive unit 110).

[0072] Based on the above discussion, the getter 4 in this embodiment can be prepared by powder sintering, and the specific process is as follows:

[0073] 1) Powder preparation: The selected getter 4 alloy material is made into powder by atomization and other methods to ensure that the powder has a suitable particle size distribution, so as to ensure the uniformity and getter performance of the subsequent sintering process.

[0074] 2) Mold forming: The prepared getter 4 powder is placed into a specific mold and a certain pressure is applied to make it initially form a getter 4 blank. The shape and size of the mold are determined according to the area and shape of the getter 4 on the stepped hole wall structure 22 in the support frame plate 2.

[0075] 3) Sintering treatment: The formed getter blank is placed in a high-temperature furnace for sintering. The sintering temperature, time and atmosphere parameters in the high-temperature furnace are reasonably controlled to make the powder particles metallurgically bonded to form getter elements with certain strength and pore structure. Among them, the appropriate pore structure in the getter element is conducive to gas diffusion and adsorption, and improves the getter efficiency.

[0076] 4) Cleaning and testing: The sintered getter element is cleaned to remove impurities and contaminants from the surface; then the getter performance is tested, such as by measuring the getter rate, getter capacity and other indicators, to screen out qualified getters.

[0077] 5) Installation and activation: Install the qualified getter 4 onto the stepped surface of the inner stepped hole wall structure 22 of the support frame plate 2, and connect it to the activation electrode 20 through the electrode. After the encapsulation is completed, the getter 4 is activated by energizing the activation electrode 20, and it can start to perform the getter function.

[0078] The getter 4 prepared above has stable performance and good mechanical properties and getter properties.

[0079] In this embodiment, the getter 4 can be prepared by thin film deposition, and the specific process is as follows:

[0080] 1) Substrate treatment: The stepped surfaces of the stepped hole wall structure 22 of the supporting frame plate 2 are cleaned and pretreated to improve the adhesion between the film and the substrate. Pretreatment methods include chemical cleaning, plasma treatment, etc.

[0081] 2) Thin Film Deposition: A getter film is deposited on the pretreated substrate surface using methods such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). During the deposition process, deposition parameters, such as deposition rate, temperature, and gas flow rate, are precisely controlled to obtain a film with uniform thickness and good getter performance.

[0082] 3) Annealing treatment: The deposited getter film is annealed. By controlling the annealing temperature and time, the crystal structure and surface morphology of the film are improved, thereby enhancing its getter activity.

[0083] 4) Performance testing: Perform getter performance testing on the annealed getter film to evaluate its getter effect and stability; if the test results do not meet the requirements, appropriate adjustments or redeposition can be made; if the test results meet the requirements, getter 4 is prepared and formed.

[0084] 5) Encapsulation and activation: After the preparation and testing of getter 4 are completed, the encapsulation operation is carried out. The support frame plate 2 is welded to the infrared chip 1 and the infrared light-transmitting sheet 3 to form a vacuum cavity. Then, the getter 4 is activated by energizing the electrodes and the activation electrode 20.

[0085] The above-mentioned method of preparing getter 4 enables the getter 4 to be ultra-thin and integrated, which is beneficial to further reduce the thickness of the support frame plate 2, and thus better suited for miniaturized infrared detectors.

[0086] As described above, the getter 4 in this embodiment needs to be activated by electricity. Based on this, an activation electrode 20 for activating the getter 4 can be further provided on the extension portion 21. The activation electrode 20 and the getter 4 are electrically connected, so that the getter 4 can be activated by electricity through the activation electrode 20.

[0087] Based on this, such as Figure 4 and Figure 5 As shown, in an optional embodiment of this application, the support frame plate 2 may further include an extension portion 21 extending outward from the outer side of the light-transmitting hole 200; the extension portion 21 and the stepped hole wall structure 22 are located on the same side of the light-transmitting hole 200; the activation electrode 20 extends along the interior of the support frame plate 2 from the stepped surface of the stepped hole wall structure 22 to the upper surface of the extension portion 21.

[0088] Based on the above discussion, in embodiments where an activation electrode 20 needs to be formed inside the support frame plate 2, the support frame plate 2 can be an alumina ceramic frame plate or a low-temperature co-fired ceramic frame plate; ceramic materials have excellent insulation properties, enabling more complex high-density wiring, and excellent airtightness. In practical applications, the preparation process of using ceramics as the material to form the support frame plate 2 may include:

[0089] 1) Mix ceramic powder (such as alumina or LTCC material) with organic binder and cast it into a green ceramic tape. Use a precision mold to punch out the frame structure and internal cavity on the green ceramic tape (in order to form light-transmitting through holes 200).

[0090] 2) Through-hole filling and circuit printing: Vertical interconnected through-holes are formed on the green ceramic sheet by laser drilling, and tungsten or molybdenum metal paste is used to fill them to form structural segments of the activation electrode 20 extending in the vertical direction; then, the wire pattern corresponding to the segment of the activation electrode 20 extending in the horizontal direction is printed on each layer of green ceramic sheet by thick film printing technology.

[0091] 3) Lamination and co-firing: The printed multi-layered green ceramic sheets are aligned, stacked, and pressed together to form an integral three-dimensional green structure; then co-fired in a high-temperature reducing atmosphere to densify the ceramic and sinter the metal conductor to form an integral ceramic framework.

[0092] 4) Post-processing and surface metallization: After co-firing, nickel / gold layers are deposited in the welding area of ​​the frame (i.e., the annular area on the trademark surface that is welded to the infrared light-transmitting sheet 3 and the infrared chip 1 respectively through the bonding layer 5) and the external pin area (the end of the activation electrode 20 exposed on the epitaxial portion 21) by electroplating or chemical plating to provide excellent solderability and corrosion resistance.

[0093] In summary, this application, on the support frame plate supporting the infrared light-transmitting sheet and the infrared chip, sets at least one side of the light-transmitting hole wall as a stepped hole wall structure for supporting the getter. That is, the getter is placed on the support frame plate, and the stepped hole wall structure, extending into the light-transmitting hole, creates a stepped surface, thus increasing the hole wall area of ​​at least one side of the light-transmitting hole to support the getter. This allows the getter area to be larger without being limited by the height of the support frame. Therefore, this application overcomes the limitation on getter area size imposed by chip miniaturization, ensuring the getter has a sufficiently large adsorption area, thereby ensuring good gettering effect on the vacuum cavity where the infrared photosensitive unit is located, and thus ensuring good device performance.

[0094] Based on any of the above embodiments, a specific fabrication process for the infrared chip packaging device of this application may include the following steps.

[0095] (1) Preparation of infrared transparent sheet 3: The whole wafer is thinned, an infrared band antireflection film is deposited by vapor deposition, and then the wafer is diced, as follows:

[0096] a. Select germanium (Ge) or silicon (Si) wafers as the substrate and thin the entire wafer;

[0097] b. Use an ultrasonic cleaner to clean the wafer surface in acetone, ethanol and deionized water in sequence, and finally dry it with nitrogen to achieve wafer surface cleaning and remove impurities and oxides.

[0098] c. Place the cleaned wafer substrate into the cavity of the vacuum evaporation equipment. Ensure the cavity is well sealed and evacuate to below 10⁻⁶ Pa to reduce the impact of gas on the film quality.

[0099] d. Select an antireflective coating material suitable for the infrared band, such as magnesium fluoride (MgF2) or zinc sulfide (ZnS). Place the vapor deposition material into an evaporation source (such as a tungsten wire or electron beam evaporation source), heat the evaporation source, and cause the vapor deposition material to evaporate and deposit on the substrate surface.

[0100] e. Control the evaporation rate (typically 0.1-1 nm / s) and film thickness (typically between tens and hundreds of nanometers, depending on optical design requirements). Monitor the film thickness in real time using a quartz crystal oscillator; after evaporation, slowly restore the chamber to atmospheric pressure and remove the wafer substrate;

[0101] f. Anneal the vapor-deposited film (temperature 200-300℃, time 1-2 hours) to improve the film's density and adhesion; dicing the wafer substrate after vapor-depositing the infrared antireflective coating.

[0102] (2) Fabrication of the support frame plate 2: Based on the dimensions of the infrared chip 1 and the infrared light-transmitting sheet 3, a three-dimensional structure of the multilayer alumina ceramic frame plate is designed, with a light-transmitting through hole 200 reserved inside to accommodate the infrared photosensitive unit 11 of the infrared chip 1, and a special gold-plated area is designed for subsequent welding and conductivity. The process is as follows:

[0103] a. Alumina ceramic green belts are prepared using a tape casting process, and the alumina ceramic green belts are precisely punched and cut to form green sheets of each layer;

[0104] b. Using precision screen printing technology, tungsten or molybdenum-manganese metal paste is printed on specific green sheets to form interlayer interconnections and gold-plated area patterns on the surface;

[0105] c. The printed green sheets are precisely aligned in the design order and laminated under high temperature and high pressure to form a whole green block;

[0106] d. The laminated green block is placed in a high-temperature sintering furnace and co-fired in a reducing atmosphere (such as nitrogen-hydrogen mixture). The temperature profile is precisely controlled (peak temperature is usually 1500-1650℃) to densify the ceramic and form a strong bond with the metallized pattern to obtain a ceramic framework.

[0107] e. The co-fired ceramic frame is cleaned and activated. A 2-5 μm thick nickel layer is deposited in the metallized area (including the area where the support frame plate 2 needs to be welded to the bonding layer 5, and the end surface area of ​​the activation electrode 20) as a barrier layer and a base layer. A 0.5-1.5 μm thick pure gold layer is electroplated or electrolessly plated on the nickel layer to form the final solderable surface.

[0108] (3) The manufacturing and welding of the getter are as follows:

[0109] a. Select an alloy foil with zirconium (Zr) as the matrix and containing other active metals (such as V and Fe), and use precision die stamping technology to stamp the alloy foil into a sheet structure as required by the design.

[0110] b. Clean the stamped sheet structure to remove oil and particulate matter to obtain a getter;

[0111] c. Fix the ceramic support frame plate 2 onto the special fixture, and use a laser welding machine to weld the getter 4 onto the support frame plate 2.

[0112] (4) The integration and welding process of the infrared light-transmitting sheet 3, the supporting frame plate 2 and the infrared chip 1 is as follows:

[0113] a. Select the appropriate solder based on the material of the welding interface (Ge window, Au plating, chip back gold) and the required sealing strength and operating temperature. For example, use gold-based solder (such as Au80Sn20) or gold-germanium (AuGe) solder, as they have excellent thermal conductivity, electrical conductivity and high strength.

[0114] b. Prepare the solder into a solder preform ring (i.e., bonding layer 5), the shape and size of which match the welding surfaces of the support frame plate 2 and the infrared light transmittance sheet 3;

[0115] c. Precisely place the infrared chip 1 (with the surface of the infrared photosensitive unit 11 facing upwards) on a special welding fixture; place the solder preformed ring on the bottom gold-plated area of ​​the support frame plate 2; flip the support frame plate 2 with the getter 4 already soldered on so that the bottom solder is aligned with the gold back of the infrared chip 1 and place it; place another solder preformed ring on the window welding gold-plated area at the top of the support frame plate 2; place the infrared light-transmitting sheet 3 with the anti-reflection coating already deposited on the top solder preformed ring;

[0116] f. Transfer the stacked components into the cavity of the vacuum reflow oven, close the oven door, and start the vacuum process to evacuate the cavity to a vacuum level of 10⁻³ Pa or higher to effectively remove gases and volatiles from the welding interface and prevent the formation of porosity. Execute the precisely set reflow soldering temperature profile:

[0117] Heating zone: Slow heating ensures even heating of the components and allows appropriate evaporation of flux (if used) in the solder paste;

[0118] Insulation zone: This zone remains below the melting point of the solder to ensure uniform temperature.

[0119] Reflow zone: Rapidly heat to above the solder liquidus line (e.g., the peak temperature of Au80Sn20 is about 300-320℃) to completely melt the solder, wet all solder surfaces, and form an airtight seal;

[0120] Cooling zone: Controls the cooling rate to form uniform and reliable solder joints and reduce thermal stress;

[0121] After welding is completed, once the temperature inside the furnace has dropped to a safe range, high-purity nitrogen is introduced into the cavity, and the finished component is removed after the pressure is restored to normal.

[0122] g. Perform a visual inspection on the components after welding to confirm that the solder filling is uniform and there are no significant deviations or defects; perform helium mass spectrometry leak detection to verify whether the hermeticity of the packaging meets the requirements, and perform necessary electrical tests and preliminary functional tests. If the tests are qualified, the infrared chip packaging device is completed.

[0123] In this embodiment, although silicon-based or germanium-based wafer-level packaging (WLP) technology can reduce the package size, the infrared light-transmitting sheet 3 is easily contaminated by microparticles during the bonding process, forming optical scattering centers and causing a decrease in the imaging signal-to-noise ratio. Therefore, in this embodiment, the infrared light-transmitting sheet 3, the support frame plate 2, and the infrared chip 1 are vacuum reflow soldered in a vacuum environment to avoid contamination of the infrared light-transmitting sheet 3.

[0124] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that the elements inherent in a process, method, article, or apparatus that includes a list of elements are included. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Additionally, portions of the technical solutions provided in the embodiments of this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0125] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of this utility model.

Claims

1. An infrared chip packaging device, characterized in that, include: An infrared chip (1) with an infrared photosensitive unit (11) formed on its upper surface. A support frame plate (2) is disposed on the upper surface of the infrared chip (1) and has a light-transmitting through hole (200) corresponding to the infrared photosensitive unit (11). An infrared light-transmitting sheet (3) is disposed on the support frame plate (2) and covers the light-transmitting through hole (200). Among them, at least one side of the light-transmitting hole (200) is a stepped hole wall structure (22) with a stepped surface; the stepped surface of the stepped hole wall structure (22) is lower than the upper edge surface of the light-transmitting hole (200); a getter (4) is covered on the stepped surface of the stepped hole wall structure (22); an activation electrode (20) connected to the getter (4) is also provided on the support frame plate (2).

2. The infrared chip packaging device as described in claim 1, characterized in that, The support frame plate (2) includes an extension portion (21) extending outward from the outside of the light-transmitting through hole (200); the activation electrode (20) extends along the interior of the support frame plate (2) from the stepped surface of the stepped hole wall structure (22) to the upper surface of the extension portion (21).

3. The infrared chip packaging device as described in claim 2, characterized in that, The diameter of the end face of the activation electrode (20) on the support frame plate (2) is not less than 1 mm.

4. The infrared chip packaging device as described in claim 2, characterized in that, The stepped hole wall structure (22) is a multi-layer stepped structure; the getter (4) is a stepped surface structure; The extension portion (21) and the stepped hole wall structure (22) are located on the same side of the light-transmitting through hole (200).

5. The infrared chip packaging device as described in claim 2, characterized in that, The stepped hole wall structure (22) is a single-layer stepped structure; and the three side walls adjacent to the light-transmitting hole are all the stepped hole wall structure (22). The getter (4) is a U-shaped structure provided along the stepped surface of the stepped hole wall structure (22) on three sides; The extension portion (21) and the side of the light-transmitting hole (200) where the stepped hole wall structure is not provided.

6. The infrared chip packaging device according to any one of claims 1 to 5, characterized in that, A shielding strip (23) is also provided on the edge of the stepped hole wall structure (22) near the center of the light-transmitting hole; the upper surface of the shielding strip (23) is higher than the upper surface of the stepped hole wall structure (22) but not higher than the upper edge surface of the light-transmitting hole (200).

7. The infrared chip packaging device according to any one of claims 1 to 5, characterized in that, The infrared photosensitive unit (11) also includes a reference infrared photosensitive unit (110) located below the stepped hole wall structure (22).

8. The infrared chip packaging device as described in claim 1, characterized in that, The thickness of the support frame plate (2) is 0.5mm~0.7mm.

9. The infrared chip packaging device as described in claim 1, characterized in that, The supporting frame plate (2) is a multi-layer ceramic plate structure formed by one or more ceramic plates selected from alumina ceramic plate, aluminum nitride ceramic plate, and beryllium oxide ceramic plate; The infrared transparent sheet (3) is any one of germanium wafer transparent sheet, silicon wafer transparent sheet or sulfur selenium glass transparent sheet.

10. The infrared chip packaging device as described in claim 9, characterized in that, The surface of the infrared light-transmitting sheet (3) is provided with any one of a magnesium fluoride coating layer, a zinc sulfide coating layer, or a metasurface structure.

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