A 3D NAND flash package device

Abstract

This application discloses a 3D NAND flash memory packaging device, comprising: a substrate; a memory control chip disposed in a first region on the upper surface of the substrate; and a stepped-stacked flash memory storage assembly disposed in a second region on the upper surface of the substrate, the stepped-stacked flash memory storage assembly comprising: at least two bare flash memory chips; the memory control chip and the stepped-stacked flash memory storage assembly are encapsulated on the upper surface of the substrate by an overall encapsulation protective layer; wherein a thermal isolation strip is disposed between the first region and the second region of the substrate; a multi-directional strain relief structure is disposed in a first adhesive layer and a solder resist insulating film between the stepped-stacked flash memory storage assembly and the upper surface; adjacent bare flash memory chips are bonded together by a second adhesive layer, the multiple second adhesive layers being arranged along the longitudinal stacking direction from the substrate toward the stepped-stacked flash memory storage assembly. This method solves early failure problems such as edge cracking of the underlying memory chip, lead root breakage, and high-frequency signal read / write distortion.

Description

Technical Field

[0001] This application relates to the field of flash memory technology, and in particular to a 3D NAND flash memory packaging device. Background Technology

[0002] In the packaging and manufacturing of modern high-capacity solid-state memory chips, a multi-chip three-dimensional stepped stacking structure is typically used to maximize storage capacity within a limited package height. This structure involves stacking multiple layers (e.g., eight, sixteen, or more layers) of non-volatile flash memory chips in a staggered manner along a single horizontal direction, and mounting them together with the memory control chip responsible for logic operations on the upper surface of the same multilayer printed circuit board (PCB) substrate. The bonding pads exposed at the stepped edges of each flash memory chip are electrically connected to peripheral connection pads on the packaging substrate via thin metal bonding wires that span the space. Finally, the entire assembly is encapsulated using epoxy molding compound, and an array of solder balls for connection to external circuit boards is arranged on the bottom surface of the substrate.

[0003] In the long-term operation of the above-mentioned multi-chip stepped stacked packaging structure and in harsh thermal cycling environments (such as minus 40 degrees Celsius to 125 degrees Celsius), early failure phenomena such as edge cracking of the underlying memory chip, breakage of the lead root, and high-frequency signal read / write distortion often occur.

[0004] Industry experts generally believe that the failure of multi-chip stacked packages is mainly caused by "overall thermal expansion mismatch due to insufficient heat dissipation of the package" or "external substrate warping". Therefore, conventional improvement directions are mostly focused on adding an external metal heat sink to the surface of the molded package or adjusting the overall coefficient of thermal expansion of the epoxy resin molding compound.

[0005] However, in-depth microscopic failure physics analysis reveals that the fundamental cause of the early failure of this structure is not uniform macroscopic deformation, but a microscopic physical mechanism hidden inside the package, induced by localized endogenous temperature differences, leading to a cascading electrical and mechanical degradation: Within a multi-layered, stacked package, the bottom first and second layers of flash memory chips are in direct contact with the high-heat-generating memory control chip, placing them in the highest heat-generating zone. Meanwhile, the top layers of flash memory chips, suspended above the heat source, are further away and in a relatively low-temperature zone. This physical distribution creates an unavoidable and inherent temperature decay gradient field along the vertical (height) direction within the package.

[0006] Under the influence of this internal temperature difference field, a non-uniform local expansion difference occurs between the uniform chip bonding insulating film and the outer epoxy molding compound covering each chip layer. This results in a high concentration of intense uniaxial shear stress at the outer edge of the cantilever step of the bottom bare chip in the stepped stack. This concentrated uniaxial shear stress not only causes microscopic interface tearing and peeling of the bottom chip bonding insulating film, but the micron-level cantilever displacement caused by peeling also directly pulls upwards at the root of the bottom high-frequency data signal lead adjacent to the edge of the step, causing fatigue microcracks in the metal at the bottom of the lead arc.

[0007] Even more insidiously, the micro-displacement at the root of the lead dynamically changes the spatial geometric spacing between adjacent densely parallel data leads. When high-frequency data transmission occurs at the flash memory interface, it causes a sudden change in the parasitic capacitive coupling between adjacent channels, thereby inducing unpredictable high-frequency electromagnetic crosstalk and eye diagram jitter.

[0008] This is a typical failure problem caused by "internal longitudinal temperature difference leading to localized mechanical shear stress concentration at the bottom edge," which in turn triggers a chain reaction of "micro-displacement at the lead root and abrupt changes in high-frequency electrical crosstalk." Conventional techniques fail to identify this localized chain-like failure mechanism and only perform global passive heat dissipation, which cannot truly solve the localized microscopic damage at the bottom edge. Summary of the Invention

[0009] This application provides a 3D NAND flash memory packaging device that solves early failure problems such as edge cracking of the underlying memory chip, breakage at the root of the lead wire, and distortion of high-frequency signal read / write.

[0010] This application provides a 3D NAND flash memory packaging device. The NAND flash memory packaging device includes: a substrate; a memory controller chip disposed in a first region on the upper surface of the substrate; and a stepped-stacked flash memory storage assembly disposed in a second region on the upper surface of the substrate. The stepped-stacked flash memory storage assembly includes: at least two bare flash chips, which are staggered and stacked in the second region along the vertical direction of the upper surface of the substrate. The memory controller chip and the stepped-stacked flash memory storage assembly are encapsulated on the upper surface of the substrate by an overall encapsulation protective layer. A thermal isolation strip is provided between the first region and the second region of the substrate. A multi-directional strain relief structure is provided in the first adhesive layer and the solder resist insulating film between the stepped-stacked flash memory storage assembly and the upper surface. Adjacent bare flash chips are bonded together by a second adhesive layer. Multiple second adhesive layers are distributed in a regular stepped gradient in terms of Young's modulus, initial thickness, and inorganic filler mass ratio along the longitudinal stacking direction from the substrate toward the stepped-stacked flash memory storage assembly. Each bare flash chip has a chip pad arrangement area at its edge. The chip pad arrangement area and the corresponding peripheral substrate connection pads on the upper surface of the substrate are vertically interconnected in a three-dimensional manner through metal bonding wires.

[0011] In some embodiments, the thermal isolation strip includes: a solder resist isolation groove formed on a solder resist insulating film on the upper surface of the substrate; a surface thermally conductive copper foil strip disposed at the bottom of the solder resist isolation groove; and a vertical thermally conductive via array disposed below the surface thermally conductive copper foil strip, penetrating the multilayer insulating medium of the substrate, and directly connected to the grounded metal heat sink layer at the bottom of the substrate.

[0012] In some embodiments, the solder mask isolation trench is distributed in a straight line or a micro-arc line along the boundary line between the first region and the second region, and its lateral extension length on the horizontal plane is greater than the adjacent side length of the storage control chip and the lowest flash memory bare chip among at least two flash memory bare chips; the opening width of the solder mask isolation trench is 100 micrometers to 180 micrometers; the solder mask isolation trench penetrates the solder mask insulating film on the upper surface of the substrate until the surface thermally conductive copper foil strip is completely exposed; at both ends of the solder mask isolation trench, the opening edge of the solder mask insulating film has a rounded chamfered structure.

[0013] In some embodiments, the surface thermally conductive copper foil strip is the same width as the solder resist isolation groove, and the thickness of the surface thermally conductive copper foil strip is 12 to 18 micrometers.

[0014] In some embodiments, the diameter of each vertical thermally conductive via in the vertical thermally conductive via array is between 50 and 80 micrometers, and the thickness of the copper plating layer on the inner wall of the via is not less than 15 micrometers, or the inside of the via is completely filled with a highly thermally conductive metal paste.

[0015] In some embodiments, the multi-directional strain relief structure includes: a plurality of regular hexagonal blind holes arranged in a periodic honeycomb pattern, with adjacent regular hexagonal blind holes isolated from each other by a common solder resist insulating wall; and a first adhesive layer forming a regular hexagonal elastic adhesive pillar insert inside each regular hexagonal blind hole.

[0016] In some embodiments, the depth of each regular hexagonal blind hole is less than the overall coating thickness of the solder resist insulating film, and the bottom of each regular hexagonal blind hole is disposed on the solder resist insulating film.

[0017] In some embodiments, at least two flash memory bare chips include a first flash memory bare chip, a second flash memory bare chip, a third flash memory bare chip, and a fourth flash memory bare chip stacked in a staggered manner along the upper surface of the substrate; the second flash memory bare chip is bonded to the first flash memory bare chip through a first second adhesive layer, the third flash memory bare chip is bonded to the second flash memory bare chip through a second second adhesive layer, and the fourth flash memory bare chip is bonded to the third flash memory bare chip through a third second adhesive layer; the Young's modulus of the first second adhesive layer is greater than that of the second second adhesive layer, and the Young's modulus of the second second adhesive layer is greater than that of the third second adhesive layer; the initial thickness of the first second adhesive layer is greater than that of the second second adhesive layer, and the initial thickness of the second second adhesive layer is greater than that of the third second adhesive layer; the inorganic filler mass percentage of the first second adhesive layer is greater than that of the second second adhesive layer, and the inorganic filler mass percentage of the second second adhesive layer is greater than that of the third second adhesive layer.

[0018] In some embodiments, the chip pad arrangement area is a cantilever step, and the second adhesive layer forms a rounded corner structure at the inner corner of the root of the cantilever step.

[0019] In some embodiments, the metal bonding leads are divided into lead unit groups. Each lead unit group includes a first ground shield lead arranged in a horizontal spatial arrangement, two adjacent high-frequency data signal leads, and a second ground shield lead. Adjacent lead unit groups share a ground shield lead located at the boundary. The data signal lead trajectory is as follows: each data signal lead adopts a low-arc spatial orientation, extending from the chip pad arrangement area and gently sloping downwards to connect to the peripheral substrate pads. The vertical net height between the highest point of its spatial arc and the upper surface of its corresponding flash memory bare chip is 60 to 80 micrometers. The ground shield lead trajectory... The traces are as follows: Each grounding shield lead adopts a towering arch bridge-shaped spatial orientation, extending upwards from the chip pad arrangement area at a preset starting angle and then sloping downwards to connect to the outer substrate pads. The vertical net height between the highest point of its spatial arc and the upper surface of the corresponding flash memory bare chip is 95 micrometers to 135 micrometers. In the longitudinal projection direction perpendicular to the substrate, the highest point of the spatial arc of each grounding shield lead is stably 35 to 55 micrometers higher than the highest point of the spatial arc of the adjacent data signal lead. The grounding shield leads form a semi-enclosed virtual coaxial electromagnetic protection cavity.

[0020] The beneficial effects of this application are: unlike the prior art, this application provides a 3D NAND flash memory packaging device, the 3D... The NAND flash memory packaging device includes: a substrate; a memory controller chip disposed in a first region on the upper surface of the substrate; and a stepped-stacked flash memory storage assembly disposed in a second region on the upper surface of the substrate. The stepped-stacked flash memory storage assembly includes: at least two bare flash chips, which are staggered and stacked in the second region along the vertical direction of the upper surface of the substrate. The memory controller chip and the stepped-stacked flash memory storage assembly are encapsulated on the upper surface of the substrate by an overall encapsulation protective layer. A thermal isolation strip is provided between the first region and the second region of the substrate. A multi-directional strain relief structure is provided in the first adhesive layer and the solder resist insulating film between the stepped-stacked flash memory storage assembly and the upper surface. Adjacent bare flash chips are bonded together by a second adhesive layer. Multiple second adhesive layers are distributed in a regular stepped gradient in terms of Young's modulus, initial thickness, and inorganic filler mass ratio along the longitudinal stacking direction from the substrate toward the stepped-stacked flash memory storage assembly. Each bare flash chip has a chip pad arrangement area at its edge. The chip pad arrangement area and the corresponding peripheral substrate connection pads on the upper surface of the substrate are vertically interconnected in a three-dimensional manner through metal bonding wires. It solves early failure problems such as edge cracking of underlying memory chips, breakage at the root of lead wires, and distortion of high-frequency signals during read and write. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the structure of an embodiment of the 3D NAND flash memory packaging device provided in this application; Figure 2 yes Figure 1 A magnified view of a portion of region A in the middle; Figure 3 yes Figure 2 A top view of a regular hexagonal blind hole; Figure 4 yes Figure 1 A magnified view of a portion of region B in the middle; Figure 5 This is a schematic diagram of one embodiment of the weld resistance isolation groove; Figure 6 yes Figure 1 A magnified view of a portion of region C in the middle; Figure 7 yes Figure 1 A magnified view of a portion of region D in the middle. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] See Figures 1 to 7 The 3D NAND flash memory packaging device includes: a substrate 100, a storage control chip 200, a stepped stacked flash memory storage component 300, a thermal isolation strip, a first adhesive layer 710, a multi-directional strain relief structure, a second adhesive layer, and an overall encapsulation protective layer 600.

[0025] In some embodiments, the storage control chip 200 is disposed in a first region on the upper surface of the substrate 100.

[0026] In some embodiments, a stepped-stacked flash memory storage component 300 is disposed in a second region on the upper surface of the substrate 100. The stepped-stacked flash memory storage component 300 includes at least two bare flash memory chips, which are stacked in a staggered manner along the upper surface of the substrate 100 in the second region. The number of bare flash memory chips may be four, five, six, or seven.

[0027] In some embodiments, the storage control chip 200 and the stepped stacked flash memory storage component 300 are encapsulated on the upper surface of the substrate 100 by an overall encapsulation protective layer 600.

[0028] In some embodiments, a thermal isolation strip is provided between the first region and the second region of the substrate 100; a multi-directional strain relief structure is provided in the first adhesive layer 710 and the solder resist insulating film 102 between the stepped stacked flash memory storage component 300 and the upper surface; adjacent flash memory bare chips are bonded together by a second adhesive layer, and multiple second adhesive layers are distributed in a regular stepped gradient in terms of Young's modulus, initial thickness and inorganic filler mass ratio along the longitudinal stacking direction from the substrate 100 toward the stepped stacked flash memory storage component 300; a chip pad arrangement area 350 is provided at the edge of each flash memory bare chip, and the chip pad arrangement area 350 and the corresponding peripheral substrate connection pads on the upper surface of the substrate 100 are interconnected in a longitudinal spanning three-dimensional electrical manner through metal bonding wires. Figure 1 In this context, 111 represents the external signal connection solder ball. 110 represents the dedicated grounding and heat dissipation solder ball.

[0029] In some embodiments, such as Figure 4 As shown, the thermal insulation strip includes: a solder resist isolation groove 400, a surface thermally conductive copper foil strip 410, and a vertical thermally conductive via array 420.

[0030] In some embodiments, a solder resist isolation groove 400 is formed on a solder resist insulating film 102 on the upper surface of the substrate 100.

[0031] The solder mask isolation trench 400 is distributed in a straight line or a slight arc along the boundary line between the first and second regions. Its lateral extension length on the horizontal plane is greater than the adjacent side length of the storage controller chip 200 and the lowest-level flash memory bare chip among at least two flash memory bare chips. The opening width of the solder mask isolation trench 400 is between 100 micrometers and 180 micrometers. The solder mask isolation trench 400 penetrates the solder mask insulating film 102 on the upper surface of the substrate 100 until the surface thermally conductive copper foil strip 410 is completely exposed. At both ends of the solder mask isolation trench 400, the opening edges of the solder mask insulating film 102 have a rounded chamfered structure 440, such as... Figure 5 As shown.

[0032] In some embodiments, a surface thermally conductive copper foil strip 410 is disposed at the bottom of the solder resist isolation groove 400.

[0033] The surface thermally conductive copper foil strip 410 has the same width as the groove of the solder resist isolation groove 400, and the thickness of the surface thermally conductive copper foil strip 410 is twelve to eighteen micrometers.

[0034] In some embodiments, the vertical thermally conductive via array 420 is disposed below the surface thermally conductive copper foil strip 410 and penetrates the multilayer insulating medium of the substrate 100, directly connected to the grounded metal heat sink layer at the bottom of the substrate 100, that is, connected to the dedicated grounded heat dissipation solder ball 110.

[0035] The diameter of each vertical thermal via in the vertical thermal via array 420 is between 50 and 80 micrometers, and the thickness of the copper plating layer on the inner wall of the via is not less than 15 micrometers, or the inside of the via is completely filled with a highly thermally conductive metal paste.

[0036] In some embodiments, such as Figure 2 and Figure 3 As shown, the multi-directional strain relief structure includes: a plurality of regular hexagonal blind holes 105. The plurality of regular hexagonal blind holes 105 are arranged in a periodic honeycomb pattern, and adjacent regular hexagonal blind holes 105 are isolated from each other by a common solder resist insulating wall 104; the first adhesive layer 710 forms a regular hexagonal elastic adhesive pillar insert 103 inside each regular hexagonal blind hole 105.

[0037] In some embodiments, the depth of each hexagonal blind hole 105 is less than the overall coating thickness of the solder resist insulating film 102, and the bottom of each hexagonal blind hole 105 is disposed on the solder resist insulating film 102. Figure 3 In the diagram, 101 represents the substrate insulating dielectric base layer.

[0038] In some embodiments, such as Figure 6 As shown, at least two flash memory bare chips include a first flash memory bare chip 301, a second flash memory bare chip 302, a third flash memory bare chip 303, and a fourth flash memory bare chip 304, which are stacked in a staggered manner along the upper surface of the substrate 100. The second flash memory bare chip 302 is bonded to the first flash memory bare chip 301 through a first second adhesive layer 720, the third flash memory bare chip 303 is bonded to the second flash memory bare chip 302 through a second second adhesive layer 730, and the fourth flash memory bare chip 304 is bonded to the third flash memory bare chip 303 through a third second adhesive layer 740. The Young's modulus of the first second adhesive layer 720 is greater than that of the second second adhesive layer 740. The Young's modulus of the second adhesive layer 730 is greater than that of the third adhesive layer 740; the initial thickness of the first adhesive layer 720 is greater than that of the second adhesive layer 730, and the initial thickness of the second adhesive layer 730 is greater than that of the third adhesive layer 740; the inorganic filler mass percentage of the first adhesive layer 720 is greater than that of the second adhesive layer 730, and the inorganic filler mass percentage of the second adhesive layer 730 is greater than that of the third adhesive layer 740.

[0039] In some embodiments, the chip pad arrangement area 350 is a cantilever step, and the second adhesive layer forms a rounded corner structure 750 at the inner corner of the root of the cantilever step. For example... Figure 7As shown, the chip pad layout area 350 is provided with a first ground pad 351, a first high-frequency data signal pad 352, a second high-frequency data signal pad 353, and a second ground pad 354 at the chip edge. Figure 7 510 is a high-position arch bridge type grounding shield lead. The peripheral substrate connection pads on the substrate 100 include a first grounding pad 120 on the substrate surface, a first high-frequency data signal pad 121 on the substrate surface, a second high-frequency data signal pad 122 on the substrate surface, and a second grounding pad 123 on the substrate surface.

[0040] In some embodiments, the metal bonding leads are divided into lead unit groups. Each lead unit group includes a first ground shield lead arranged in a horizontal spatial arrangement, two adjacent high-frequency data signal leads (520 / 530), and a second ground shield lead. Adjacent lead unit groups share a ground shield lead located at the boundary. The data signal lead trajectory is as follows: each data signal lead adopts a low-arc spatial orientation, extending from the chip pad arrangement area 350 and gently sloping downwards to connect to the peripheral substrate connection pads. The vertical net height between the highest point of its spatial arc and the upper surface of its corresponding flash memory bare chip is 60 to 80 micrometers. The lead trajectory is as follows: each grounding shield lead adopts a towering arch-shaped spatial orientation, extending upwards from the chip pad arrangement area 350 at a preset starting angle before sloping downwards to connect to the outer substrate pads. The vertical net height between the highest point of its spatial arc and the upper surface of its corresponding flash memory bare chip is 95 to 135 micrometers. Specifically, in the longitudinal projection direction perpendicular to the substrate 100, the highest point of the spatial arc of each grounding shield lead is stably 35 to 55 micrometers higher than the highest point of the spatial arc of the adjacent data signal lead. The grounding shield leads constitute a semi-enclosed virtual coaxial electromagnetic protection cavity. Figure 7 540 represents the vertical height difference of the arc-initiating space. That is, in the longitudinal projection direction perpendicular to the substrate 100, the highest point of the arc-initiating space of each grounding shield lead is stably 35 to 55 micrometers higher than the highest point of the arc-initiating space of the adjacent data signal lead.

[0041] The above methods solve early failure problems such as edge cracking of underlying memory chips, breakage at the root of lead wires, and distortion of high-frequency signals during read / write.

[0042] In one application scenario, the technical solution of this application provides a multi-layered collaborative physical packaging structure for 3D NAND flash memory, which is constructed from four mutually cooperating physical dimensions: substrate 100 microscopic multi-directional strain relief, planar thermal field physical isolation, longitudinal bonding modulus step matching, and spatial lead three-dimensional shielding. 1. Microscopic multi-directional strain relief structure of substrate 100 surface layer.

[0043] I. Spatial hierarchy and overall layout relationship.

[0044] In a multi-layer chip ladder stacked packaging system, the upper surface of the packaging substrate 100 defines a storage die-bonding region specifically for supporting the bottom first flash memory bare chip 301. This microscopic multi-directional strain relief structure is formed on the surface solder resist insulating film 102 of the substrate 100 within the storage die-bonding region, directly below the bottom surface of the bottom first flash memory bare chip 301, and is completely covered and filled by the bottommost chip adhesive layer.

[0045] The structure spatially covers the entire projected area of ​​the first flash memory bare chip 301, and extends to the outer edge of the outer step in the stepped stacking system, which bears the cantilever force and the maximum internal temperature difference, in order to establish a micro-mechanical strain buffer layer at the die bond interface closest to the bottom of the package heat generation.

[0046] II. Microscopic geometric topology and structural features.

[0047] A honeycomb microcavity array with closely arranged regular hexagons.

[0048] The microscopic multi-directional strain relief structure is composed of a number of regular hexagonal micro-blind holes arranged in a periodic honeycomb pattern within the solder resist insulating film 102 on the surface of the substrate 100.

[0049] Each hexagonal micro-blind hole is surrounded by six sidewalls arranged symmetrically at 120 degrees. Adjacent micro-blind holes are isolated from each other by a shared solder resist insulating wall 104, forming a continuous interwoven honeycomb-like micro-skeleton grid.

[0050] The specific engineering dimensions are defined as follows: Blind via depth: The depth of each regular hexagonal micro blind via is limited to eight to fifteen micrometers. This depth is less than the overall coating thickness of the solder resist insulating film 102 on the surface of the substrate 100, ensuring that a complete insulating solder resist medium is retained at the bottom of the blind via, without damaging the electrical insulation layer inside the substrate 100.

[0051] Aperture size: The width of opposite sides (aperture) of each regular hexagonal micro blind aperture is limited to 25 micrometers to 40 micrometers.

[0052] Sidewall thickness: The thickness of the solder resist insulation wall 104 between two adjacent micro-blind holes is limited to 12 to 18 micrometers.

[0053] This size configuration ensures that the solder mask skeleton has sufficient mechanical tear resistance during photolithography and development, while also allowing the opening area of ​​the micro-blind vias to accommodate the full microscopic flow of the adhesive during thermosetting and curing.

[0054] The gradually densified layout of the outer high-stress zone is as follows: In the central region of the storage die-bonding area, the regular hexagonal micro-blind holes are arranged in a uniformly spaced manner; At the four corners of the bottom-level first flash memory bare chip 301 and in the high-stress area of ​​the outer stepped cantilever edge, the aperture size of the micro-blind vias gradually decreases from the inside to 20 to 25 micrometers, and the thickness of the solder resist insulating wall 104 is correspondingly increased to 15 to 20 micrometers. By increasing the density of the honeycomb wall grid in the edge region, the microscopic load-bearing stiffness under the edge cantilever is specifically enhanced.

[0055] III. The interface bonding and assembly manufacturing mechanism is as follows: Using a photolithography and development integrated molding process, the honeycomb micro blind hole array is directly formed by mask exposure and development of the photosensitive solder resist on the surface of the substrate 100, without the need for additional metal etching or physical laser micromachining steps, and is fully compatible with the existing multilayer circuit board 100 manufacturing process.

[0056] The self-assembly anchoring of micron-level elastic die bond pillars is adopted. During the hot-press die bonding stage of the bottom first flash memory bare chip 301, the first adhesive layer on the bottom surface of the chip softens and generates micro-flow under the action of the set hot-pressing temperature and vertical pressure. It is completely squeezed into and fills the interior of each regular hexagonal micro blind hole, and the air inside the hole is expelled. After cooling and curing, the first adhesive layer integrally forms tens of thousands of micron-sized regular hexagonal elastic adhesive pillar inserts 103 inside the micro-blind holes. These adhesive pillar inserts form a three-dimensional, all-around mechanical engagement and micro-anchoring with the six sides of the solder resist insulating wall 104, constructing a highly adhesive composite elastic damping layer between the bottom surface of the first flash memory bare chip 301 and the packaging substrate 100.

[0057] IV. Stress relief and multi-directional strain dispersion mechanism.

[0058] In harsh operating temperature rise and thermal cycling environments, this structure achieves stress relief and avoids localized fracture failure through the following physical mechanisms: On a conventional flat substrate with a surface thickness of 100, the chip's thermal expansion and unidirectional shear displacement accumulate continuously, resulting in extreme stress concentration at the outer edge of the bottom stepped cantilever and interface tearing and peeling.

[0059] This solution uses a honeycomb micro-blind hole substrate 100. The chip thermal expansion, the colloid discretized by hexagonal microcavities, the micro-displacement evenly distributed by the six-way sidewalls, and the elimination of unidirectional concentrated shear peaks.

[0060] The isotropic strain dispersion mechanism is as follows: When the adhesive layer on the surface of the conventional flat substrate 100 is heated, the lateral deformation displacement caused by the difference in thermal expansion coefficients between the chip and the substrate 100 will accumulate unidirectionally in the plane, and eventually all of it will be transferred and concentrated at the outer end of the bare chip stepped cantilever, forming a very large unidirectional interface shear stress peak. In this design, the continuous planar adhesive layer is divided into discrete micropillars embedded within honeycomb micro-blind holes. Due to the hexagonal geometry's six-axis symmetry, when the chip undergoes planar expansion and contraction, the uniaxial tensile or compressive force on each micropillar is uniformly borne by the six symmetrical sidewalls of the micro-blind hole. This decomposes the macroscopic uniaxial concentrated shear stress into micron-level isotropic multiaxial compressive deformation around the hole walls, thus physically preventing stress accumulation at the cantilever ends.

[0061] The physical barrier that arrests microcracks at the thermal cycling interface is as follows: During long-term temperature alternating fatigue testing, even if a very small amount of adhesive layer fatigue peeling occurs at the edge of a few micro-blind holes, the microcracks are completely confined to a single closed microcavity due to the physical spatial barrier of the honeycomb grid solder mask wall. They cannot extend laterally along the flat interface to form a macroscopic peeling surface, thus completely eliminating the hidden danger of large-area interface tearing of the bottom layer chip adhesive film.

[0062] The effect of protecting the electrical integrity of the bond wire root is as follows: Because the peak value of interface shear deformation below the step edge of the bottommost first flash memory bare chip 301 is completely suppressed, the edge cantilever of the first flash memory bare chip 301 always remains flat and stable, and will not undergo micron-level up and down warping displacement. This eliminates the reciprocating mechanical pulling on the metal lead roots bonded to the edge pads of the first flash memory bare chip 301 caused by the micro-displacement of the chip edge, completely protecting the metal grain boundaries at the root of the lowest high-frequency data signal lead from fatigue micro-fracture, while ensuring the constant geometric spacing of the lead space and eliminating high-frequency electromagnetic crosstalk distortion caused by lead micro-displacement.

[0063] 2. Planar thermal field physical isolation path between the storage area and the control chip area.

[0064] I. Spatial layout and physical isolation trench construction.

[0065] On the upper surface of the multilayer insulated circuit packaging substrate 100, the overall planar area is divided into a storage control chip 200 mounting area responsible for data logic calculation and a stepped stacked storage area responsible for high-density data storage.

[0066] The planar thermal field physical isolation path is located on the boundary transition zone between the mounting area of ​​the storage control chip 200 and the stepped stacked storage area. Its main structure is a transverse through solder mask isolation groove 400 extending perpendicular to the chip misalignment stacking direction.

[0067] The geometry of the transverse through-slot is as follows: The transverse through solder mask isolation groove 400 is distributed in a straight line or a slight arc along the boundary line between the two installation areas, and its transverse extension length on the horizontal plane is greater than the adjacent side length of the storage control chip 200 and the bottommost bare flash memory chip. The width of the groove is limited to 100 micrometers to 180 micrometers for the transverse through-type weld resistance isolation groove 400. The depth of the isolation trench is such that it completely penetrates the solder resist insulating film 102 on the surface of the substrate 100 (the penetration depth is usually 15 to 25 micrometers) until the internal metal copper foil layer on the surface of the substrate 100 is completely exposed, forming a physical interruption of the solder resist dielectric layer on the surface of the substrate 100.

[0068] The tear-resistant rounded transition at the groove end is as follows: At the left and right ends of the transverse through-hole solder resist isolation groove 400, the opening edge of the solder resist insulating film 102 is designed as a rounded chamfered transition structure with a diameter of not less than fifty micrometers, in order to avoid stress concentration tearing caused by the right-angle tip of the solder resist groove during subsequent reflow soldering and thermal alternation.

[0069] II. Design of internal heat conduction pathways and vertical flow distribution paths.

[0070] To prevent the large amount of concentrated heat generated during the operation of the memory control chip 200 from spreading laterally along the surface of the substrate 100 to the stepped stacked memory area, this physical isolation pathway constructs a forced vertical rapid heat conduction and sinking channel inside the substrate 100: The exposed high thermal conductivity copper foil busbar has a continuous surface thermally conductive copper foil strip 410 that is the same width as the tank body and extends completely exposed at the bottom of the transversely penetrating solder resist isolation groove 400. The copper foil strip is 12 to 18 micrometers thick, made of high-purity electroplated copper, and is not coated with any insulating solder resist during the manufacturing process.

[0071] The vertical thermal via array 420 is arranged in a close arrangement, directly below the metal copper foil strip at the bottom of the transverse through solder resist isolation groove 400. The substrate 100 has a vertical thermal metal via array arranged in two rows in an alternating pattern. The diameter of each vertical thermally conductive metal via is limited to 50 to 80 micrometers, and the thickness of the copper plating layer on the inner wall of the via is not less than 15 micrometers, or the inside of the via is completely filled with a high thermal conductivity metal paste. The set of vertical thermally conductive metal vias penetrates the multilayer insulating medium of the substrate 100 through the thermally conductive copper foil strip on the surface of the substrate 100, and is directly connected to the grounded metal heat sink layer at the bottom of the substrate 100. They are also directly connected to a set of dedicated grounded heat dissipation solder balls on the bottom surface of the package substrate 100.

[0072] The vertical heat dissipation path and the lateral blocking work together. The heat dissipation vias on the bottom of the storage control chip 200 and the vertical heat-conducting metal via array below the isolation trench together form a vertical heat dissipation channel with low thermal resistance. This forces the concentrated heat flow generated by the control chip during operation to be introduced into the external motherboard circuit along the longitudinal direction, making its longitudinal heat conduction efficiency much higher than the lateral heat conduction efficiency of the dielectric layer of the substrate 100.

[0073] III. Colloidal flow barrier and filling mechanism of low thermal conductivity molding compounds.

[0074] This physical isolation pathway plays a dual role in material interface control during chip packaging, mounting, and injection molding processes: The physical barrier function of blocking the lateral bridging of liquid colloids is as follows: During the die bonding stage of the storage controller chip 200 and the bottommost bare flash memory chip, if a small amount of liquid adhesive overflows laterally from the bottom of the controller chip, the recessed space of the horizontally penetrating solder resist isolation groove 400 can serve as a natural overflow groove to physically cut off the overflowing adhesive. This mechanism effectively prevents the high thermal conductivity of the chip adhesive from forming a lateral thermal bridge between the control chip and the memory chip, and avoids the high temperature of the control chip being directly conducted to the sidewall edge of the first flash memory bare chip 301 through the overflowing adhesive layer.

[0075] The low thermal conductivity molding compound forms a transverse thermal insulation barrier. In the subsequent overall molding process, the molten epoxy resin molding compound is completely injection molded into the recessed cavity of the transverse through-weld barrier groove 400. Because the cured epoxy molding compound has extremely low thermal conductivity (typically 0.7 to 1.5 watts per meter Kelvin), the epoxy molding compound block filled in the isolation groove forms a high thermal resistance physical insulation wall between the two chip mounting areas, which greatly increases the lateral thermal resistance of the substrate 100 surface layer from the control chip to the memory chip.

[0076] IV. Synergistic protection effect of eliminating thermal stress on the bottom layer of storage stack.

[0077] The planar thermal field physical isolation pathway, in conjunction with the multi-layered stepped stacked chip structure, produces a clear physical cooling and stress relief effect: In a conventional non-isolated substrate 100, the control chip generates concentrated heat, the surface solder mask and copper foil are baked laterally, the edge of the bottom layer 1 flash memory bare chip is overheated, and the Z-axis temperature gradient and shear stress are aggravated.

[0078] This solution features an isolated pathway substrate 100, which controls the concentrated heat generation of the control chip. When encountering a through-hole solder resist slot (thermal insulation wall), most of the heat is directly discharged to the bottom solder ball through the vertical metal via, blocking lateral diffusion.

[0079] That is, the edge of the bare chip of the first layer of flash memory is kept at a low temperature and stable, eliminating the endogenous temperature difference field of the stepped stacking system and protecting the root of the lead.

[0080] By blocking local thermal crosstalk and reducing the edge temperature of the bottom chip, the dual effect of high thermal resistance in the lateral direction and low thermal resistance in the vertical direction reduces the local temperature rise of the bottom first flash memory bare chip 301 near the control chip by twelve to eighteen degrees Celsius when the control chip is under high load operation.

[0081] This fundamentally reduces the source of thermal stress at the bottom of the steps, greatly reducing the longitudinal internal temperature difference span of the multi-layer stepped stacked memory module under working conditions, so that the temperature stress borne by the adhesive film of each chip layer in the stack is within a controllable and gradual range. This eliminates the "peak value of unidirectional shear stress at the cantilever edge of the bottom first flash memory bare chip 301" which is further aggravated by the local overheating baking of the control chip. Together with the microscopic multi-directional strain relief structure on the surface of the substrate 100, it forms a double linkage protection between the upper and lower parts, which completely ensures the structural stability and electromagnetic transmission quality of the root of the bottom high-frequency data signal lead.

[0082] 3. A chip adhesive layer system with variable elastic modulus that varies longitudinally in a stepped manner.

[0083] I. Vertical hierarchical gradient architecture and spatial configuration.

[0084] In a multi-chip package structure with stepped unidirectional staggered stacking, multiple layers (e.g., four, eight, or sixteen layers) of non-volatile flash memory bare chips of the same thickness are stacked sequentially in a unidirectional staggered manner along the longitudinal direction (height direction) perpendicular to the substrate 100. The same edge of each bare chip extends outward, exposing the pad arrangement area for bonding connection.

[0085] The variable elastic modulus chip bonding layer system includes multilayer cured chip bonding insulating films sandwiched between two adjacent layers of flash memory bare chips. Along the longitudinal stacking direction from the packaging substrate 100 toward the top layer, the multilayer chip bonding insulating films exhibit a regular step-like gradient distribution in three physical dimensions: Young's elastic modulus, initial film thickness, and inorganic filler mass ratio. This divides the entire three-dimensional stack longitudinally into a bottom high-rigidity shear-resistant zone, an intermediate transition modulus zone, and a top high-compliance strain-absorbing zone.

[0086] For example, the top layer low-modulus film has a thickness of 7-9 micrometers and a modulus of 0.9-1.3 GPa; the middle transition film has a thickness of 12-16 micrometers and a modulus of 1.8-2.5 GPa; and the bottom layer high-modulus film has a thickness of 18-22 micrometers and a modulus of 3.0-3.8 GPa.

[0087] II. Control of physical properties and material composition of adhesive films for each chip layer.

[0088] The insulating adhesive film for bonding each layer of the chip is composed of a modified epoxy resin matrix, an acrylic synthetic rubber elastomer, and micron-sized spherical silica inorganic insulating fillers. By precisely controlling the crosslinking and curing density of the polymer resin and the mass percentage of the inorganic fillers, a stepped configuration of the physical properties of each layer of the adhesive film is achieved. The bottom layer of high-rigidity, shear-resistant adhesive film (located between the first and second layers of flash memory bare chips) is as follows: Physical property parameters are limited as follows: the Young's modulus after curing is limited to 3.0 GPa to 3.8 GPa, the thickness is limited to 18 micrometers to 22 micrometers, and the coefficient of thermal expansion is limited to 20 to 35 x 10 to the power of negative 6 per Kelvin. Material microstructure ratio: The modified epoxy resin adopts a high cross-linking density formula, and the mass ratio of spherical silica inorganic filler is limited to 60% to 70%. Function and role: The bottom layer is located in the high-temperature concentrated area closest to the substrate 100 and the control chip. The high proportion of inorganic fillers gives the film extremely high shear strength and extremely low coefficient of thermal expansion, which can firmly lock the bottom bare chip and resist the severe interfacial shear slippage between the substrate 100 and the silicon chip under high temperature conditions.

[0089] The top layer of high-compliance strain-absorbing adhesive film (located between the top two layers of bare flash memory chips) is as follows: Physical property parameters are limited as follows: the Young's modulus after curing is limited to 0.9 GPa to 1.3 GPa, the thickness is limited to 7 micrometers to 9 micrometers, and the elongation at break is not less than 15%. Material microstructure: Increase the proportion of acrylate elastomer copolymer to reduce crosslinking stiffness, and reduce the mass proportion of spherical silica inorganic filler to 20% to 35%. Function and role: The top bare chip is 100 degrees away from the heat source on the substrate, and its operating temperature is significantly lower than that of the bottom layer, but it bears the macroscopic bending warping moment formed by the cumulative microscopic deformation of the underlying layers. The ultra-thin adhesive film with high flexibility and low modulus acts as a macroscopic deformation absorption pad, accommodating the warping deformation of the top layer with minimal reaction force, while reducing the overall package thickness of the stack.

[0090] The intermediate transition modulus films (the intermediate chip layers located between the bottom and top layers) are as follows: Physical property parameters are limited: from bottom to top, the Young's modulus of each intermediate layer of the adhesive film decreases linearly from 2.8 gigapascals to 1.4 gigapascals, and the film thickness decreases from 16 micrometers to 10 micrometers. Function: Eliminates abrupt changes in material stiffness in the vertical direction, forming a continuous and smooth mechanical transition zone, and preventing stress from concentrating again in a specific intermediate layer.

[0091] III. Microscopic morphology of the adhesive corner covering at the edge of the stepped cantilever.

[0092] During the chip ladder stacking process, the misalignment distance between adjacent upper and lower flash memory bare chips is limited to 150 micrometers to 300 micrometers, so that the upper surface edge of each bare chip forms a cantilever ladder platform for bonding metal leads.

[0093] The geometric shape of excess material during hot pressing is defined as follows: During the hot press mounting process, the adhesive on the bottom surface of the upper bare chip softens under heat and undergoes micro-extrusion and overflows, spontaneously curing at the inner corner of the root of the cantilever step to form a rounded micro-adhesive corner (corner wrapping structure) that transitions smoothly outward. Climbing height and epitaxial width: The vertical height of the micro-adhesive corner climbing upward along the sidewall of the upper bare chip is limited to one-third to one-half of the thickness of the upper bare chip itself, and the horizontal width of the micro-adhesive corner extending outward along the upper surface of the lower bare chip is limited to fifteen micrometers to thirty micrometers, and the outer surface presents a smooth concave arc transition surface.

[0094] The mechanisms for eliminating stress singularities in cantilever structures and preventing cracking are as follows: This micro-adhesive corner completely eliminates the stress singularity effect at the right angle within the chip misalignment step, dispersing the peeling stress that was originally concentrated at the sharp edge at the bottom of the chip into a passivation stress that is uniformly distributed along the tangent direction of the arc surface. This completely blocks the physical path of microcracks initiating from the inner corner of the step and propagating into the chip during temperature cycling.

[0095] IV. Synergistic Mechanism of Longitudinal Thermal Strain Synergy and Lead Bond Stiffness.

[0096] The variable elastic modulus chip adhesive layer system generates the following cooperative force mechanism during physical operation: In conventional uniform film stacking, the bottom layer experiences high temperatures, excessive heat softening of the film, cantilever sagging at the stepped edges, lead pad collapse, and fatigue at the solder joint roots. The top layer experiences low temperatures, excessive film stiffness leading to embrittlement, lack of release of bending torque, and cracking at the corners of the top-layer chip.

[0097] This design utilizes a variable modulus system. The bottom high-temperature zone features a high-modulus rigid adhesive film that maintains high rigidity even at high temperatures, ensures no loss of ultrasonic energy during wire bonding, and eliminates micro-displacement of the solder pads. The top low-temperature zone features a low-modulus flexible adhesive film that absorbs accumulated bending deformation moments, and dynamically synchronizes the expansion and contraction deformation of all layers throughout the entire height.

[0098] The dynamic synchronization of full-height thermal expansion deformation addresses the inherent non-uniform temperature field of "high bottom temperature and low top temperature" in multi-chip stacked packages. This solution uses a gradient design of "low thermal expansion coefficient film for the bottom layer and high flexibility film for the top layer" to ensure that the actual lateral thermal expansion of each layer due to local temperature rise multiplied by local material linear expansion rate is macroscopically equal and synchronized across the entire Z-axis height. It completely eliminates the overall columnar distortion and stepped misalignment shear tearing caused by the severe uneven expansion and contraction of the upper and lower layers.

[0099] Provides a high-rigidity hard base for bottom-layer wire bonding. When performing metal wire bonding (ultrasonic thermoforming ball bonding process) on the exposed pads at the edges of the bare chip steps, the bottommost step cantilever is covered by a hard adhesive layer with high modulus and high filler content, which can provide a strong rigid mechanical support and avoid the "cantilever sagging and bouncing effect" when ultrasonic waves and mechanical pressure are applied, ensuring that the metal wires are firmly balled on the first layer of bare chip pads; This eliminates the increased contact resistance and high-frequency signal attenuation caused by poor soldering or microcracks at the root of the bottom lead, thus completely ensuring the manufacturing yield and long-term operational reliability of multilayer stacked flash memory devices.

[0100] 4. A three-dimensional electromagnetic shielding lead network with varying heights and depths.

[0101] I. Spatial lead network layout and pin period allocation.

[0102] In a multi-chip package structure with staggered stacking in a stepped manner, the chip pad arrangement area 350 exposed at the edge of each layer of flash memory bare chip steps, and the peripheral substrate connection pads corresponding to the upper surface of the package substrate 100, are interconnected vertically across three dimensions by a large number of fine metal bonding leads (such as high-purity gold wires, palladium-coated copper wires or silver alloy leads, with a lead diameter of fifteen to twenty micrometers).

[0103] The three-dimensional electromagnetic shielding lead mesh is arranged in physical space according to a strict functional periodic grouping topology. Specifically, along the edge pad arrangement direction of each layer of flash memory bare chip, the metal bonding leads are sequentially divided into periodically arranged lead unit groups: Each lead unit group strictly follows the horizontal spatial arrangement order of "one first ground shield lead, two adjacent high-frequency data signal leads, and one second ground shield lead"; Between two adjacent lead unit groups, a grounding shield lead is shared at the boundary, so that on both sides of all adjacent data signal lead pairs on the entire lead layout, grounding shield leads providing zero potential reference are symmetrically sandwiched.

[0104] II. Defining the height difference and spatial orientation of the three-dimensional arc.

[0105] To break the continuous parallel coupling surface formed by conventional flush leads over long distances, this technique assigns differentiated spatial arc trajectories and three-dimensional height differences to the grounding shield lead and the data signal lead: The tiered control of vertical height difference is as follows: Data signal lead trajectory: Each data signal lead adopts a low arc spatial orientation, which is led out from the chip pad and then quickly and gently slopes down to connect to the substrate 100 pad. The vertical net height of the highest point of the spatial arc from the upper surface of the chip is limited to 60 to 80 micrometers. Grounding shield lead trajectory: Each grounding shield lead adopts a tall arch bridge-shaped spatial orientation, extending upwards at a large starting angle after being led out from the chip grounding pad. The vertical net height of the highest point of the spatial arc from the upper surface of the chip is limited to 95 micrometers to 135 micrometers. Height difference limitation: In the longitudinal projection direction perpendicular to the package substrate 100, the highest point of the spatial arc of each ground shield lead is stably 35 to 55 micrometers higher than the highest point of the spatial arc of the adjacent data signal lead.

[0106] The spatial lateral span and geometric offset orientation are as follows: After the grounding shield lead rises to the highest point of the arc, its lead-crossing path on the horizontal projection plane forms a small outward divergence angle (the angle is two to five degrees) relative to the data signal lead. This results in the grounding shield lead forming a "three-dimensional, arched umbrella-shaped" protective envelope that crosses diagonally upwards and covers the outside of adjacent data signal leads.

[0107] III. Spatial semi-enclosed electromagnetic shielding structure and impedance matching mechanism.

[0108] This three-dimensional lead mesh, through the geometrical cooperation between the grounding metal wire and the internal grounding layer of the packaging substrate 100 in three-dimensional space, constructs a semi-enclosed virtual coaxial electromagnetic protection cavity for high-speed transmission channels: The four-sided electromagnetic isolation cavity is formed as follows: Lateral shielding: The two grounding shielding leads on both sides act as lateral grounding conductive pillars along the entire length of the lead, cutting off the lateral electromagnetic force lines penetrating between adjacent different data signal lead groups; Top shielding: The arc-shaped metal section formed by the grounding shield lead at the top creates a zero-potential space boundary directly above the data signal lead pair, absorbing the radiated magnetic field emanating outward from the arc top of the lead. Bottom shielding: A large area of ​​continuous grounded copper foil shielding layer is arranged on the upper surface of the package substrate 100 in the area inside the pad, which together with the upper lead forms the lower boundary reference surface.

[0109] Thus, around each pair of high-frequency data signal leads, an inverted trapezoidal semi-enclosed electromagnetic shielding microcavity is formed, consisting of the "upper grounding lead arc top, the two side grounding lead sidewalls, and the lower substrate 100 grounding copper foil".

[0110] The high-frequency signal characteristic impedance is uniformly controlled. The semi-enclosed shielded cavity provides a closed and uniform spatial return path for the data signal lead, so that the effective distributed inductance and distributed capacitance of the high-frequency data lead are kept highly symmetrical throughout the entire suspended span. The high-frequency characteristic impedance fluctuation of the metal lead span is strictly controlled within ±7% of the set standard value (e.g., fifty ohms), effectively eliminating high-frequency signal reflection caused by impedance abrupt changes.

[0111] IV. Multi-layer stepped lead wire three-dimensional avoidance and injection-molded anti-impact wire structure.

[0112] In the case of dense lead arrays in multi-layer chips with stacked layers of up to sixteen layers, this structure balances space-saving short-circuit protection with injection molding process stability. The spatial misalignment of the staggered leads avoids three-dimensional gaps, with the exposed width of the stepped misalignment between adjacent chip layers ranging from 150 micrometers to 300 micrometers. The starting point of the pads of the lead group located on the upper chip rises layer by layer in the height direction, and the substrate 100 landing pads of the upper lead group extend outward in a radial pattern. The radii of curvature of the adjacent upper and lower lead wires in three-dimensional space are different. Throughout the entire suspended crossing path, the minimum air gap between the upper and lower lead wires is always maintained at no less than 25 micrometers, which completely eliminates the physical risk of lead wire overlap short circuit from a geometrical perspective.

[0113] The anti-impact stability of epoxy resin molding compound filling is achieved by the undulating and staggered lead wire mesh forming a discontinuous and discrete fluid resistance interface in the direction of injection flow of the molding compound, thus avoiding the "large area windbreak effect" of traditional flat and dense lead wire arrays. During the molding compound molten injection process, the molding compound can smoothly pass through the uneven gaps between the grounding lead and the data lead, significantly reducing the unidirectional lateral thrust generated by the melt flow on the fine metal lead. This controls the lateral offset of the bonding lead during the injection molding process to less than five percent of the lead's own diameter, ensuring the precise shape of the three-dimensional shielding geometry after curing.

[0114] V. The resulting electromagnetic and signal integrity technology effects.

[0115] The spatially layered, undulating three-dimensional electromagnetic shielding lead network, working in synergy with the underlying microscopic strain-dissipating structure, produces a clear and significant improvement in electrical performance: Completely suppressing capacitive electromagnetic crosstalk between high-frequency data channels, relying on the strong confinement of high-frequency electromagnetic fields by the semi-enclosed shielded microcavity, when the memory chip performs full-channel concurrent read and write at a high frequency of more than 2,400 megabits per second, the near-end differential capacitive crosstalk noise and far-end inductive crosstalk noise between adjacent data signal leads are suppressed to below -38 dB.

[0116] To eliminate the deterioration of eye diagram jitter caused by environmental temperature stress, when the device is subjected to extreme temperature alternation test, even if the underlying bare chip undergoes extremely weak micron-level thermal deformation, because each set of data leads is firmly constrained inside its own independent three-dimensional shielded microcavity, the small disturbance of the geometric spacing between the leads will not cause a sudden change in the electromagnetic coupling state. This reduces the timing jitter (eye diagram horizontal jitter) during high-speed data transmission by more than 70%, ensuring zero bit error rate and long-term communication stability for flash memory devices under harsh industrial electromagnetic and temperature environments.

[0117] 5. Overall encapsulation protective layer 600.

[0118] I. Spatial Enclosure Shape and Geometric Dimensions.

[0119] After the assembly and interconnection of the stepped stacked memory components, memory control chip 200 and three-dimensional bonding wire network are completed, the overall encapsulation protective layer 600 serves as the final external rigid physical protective barrier, integrally molded and covering the upper surface of the encapsulation substrate 100.

[0120] Three-dimensional shape and thickness control The overall encapsulation protective layer 600 has a rectangular plate-shaped solid structure. Its bottom surface is completely attached to and firmly bonded to the upper surface of the encapsulation substrate 100. Its top surface is a flat plane. The outer contour boundary of the overall encapsulation protective layer 600 is flush with the outer edge of the encapsulation substrate 100. Total encapsulation thickness: The total vertical encapsulation thickness of the overall encapsulation protective layer 600 from the upper surface of the encapsulation substrate 100 to its own top surface is limited to 0.65 mm to 0.95 mm, so that the total height of the entire multi-chip package device, including the encapsulation substrate 100 and the bottom solder ball, is strictly maintained within the standard thin device size range of 1.10 mm to 1.20 mm. Top safety coverage margin: In the vertical height direction perpendicular to the packaging substrate 100, the top surface of the overall packaging protective layer 600 is 50 to 80 micrometers higher than the arc tip of the tallest ground shield lead in the bonding lead group, ensuring that the tall lead does not expose copper or mechanical wear during long-term use.

[0121] The micro-gap and deep trench are filled without voids. The overall encapsulation protective layer 600 completely penetrates downward and fills the misaligned step micro-gap between each layer of flash memory bare chips, the micron-level gap between metal leads, and the aforementioned transverse through solder mask isolation trench 400 located between the control chip and the memory stack area, forming a dense continuous phase medium entity without micro-pores (cavitation defect size is less than three micrometers).

[0122] II. Composition and Gradation Regulation of Composite Micromaterials and Multi-peak Microspheres

[0123] The overall encapsulation protective layer 600 is composed of a modified thermosetting resin matrix, spherical inorganic fillers with multi-peak particle size distribution, stress-relieving modified microparticles, and a curing crosslinking accelerator. The high-flow, low-stress resin matrix is ​​made from a polyaromatic cyclobiphenyl-modified epoxy resin and phenolic resin curing agent system with low melt viscosity. This resin matrix exhibits extremely low melt dynamic shear viscosity (melt viscosity less than 10 Pascals per second) at molding temperatures ranging from 165°C to 175°C, giving the molding compound excellent micro-gap penetration capability.

[0124] The three-peaked particle size distribution spherical silica micro powder filler uses high-purity spherical silica micro powder that has undergone surface coupling modification treatment. The total mass ratio of the filler in the overall encapsulation protective layer 600 is limited to 85% to 90%. Multi-peak size combination characteristics: The first particle size component (main support skeleton): with an average particle size of 15 to 25 micrometers, accounting for 50% to 60% of the total filler mass, is used to maximize the increase of filler packing density and reduce the overall thermal expansion coefficient of the matrix material. The second particle size component (interstitial filling phase) has an average particle size of three to eight micrometers and accounts for 25% to 35% of the total filler mass. It is used to fill the coordination voids between large microspheres. The third particle size component (ultrafine flow lubricating phase): with an average particle size of 0.1 to 0.8 micrometers, accounting for 10% to 15% of the total filler mass. These submicron-sized microspheres act as microscopic rolling bearings during melt injection, significantly reducing flow resistance and ensuring that the molding compound can smoothly pass through the undulating three-dimensional lead wire mesh with a spacing of only about 20 micrometers, without filler aggregation or lead wire pushing.

[0125] Ultra-low radioactivity control: The content of uranium and thorium radioactive isotopes in the selected spherical silica filler is extremely low, and the alpha ray emission rate is strictly controlled to less than 0.001 counts per square centimeter per hour, eliminating soft failure interference caused by the self-radiation of the molding compound to the charge stored in high-density non-volatile flash memory.

[0126] III. The complete wetting and shape-preserving mechanism of complex grooves and three-dimensional lead mesh.

[0127] During vacuum-assisted transfer injection molding or compression molding, the overall encapsulation protective layer 600 exhibits highly coordinated flow and anchoring with the internal structures: For example, the molten molding compound is injected under low pressure, smoothly passes through the three-dimensional high and low lead mesh, the high and low leads are discretely distributed to destroy the flow obstruction surface, the wire offset rate is reduced to less than 5%, the transverse through-insulation groove is completely filled, the ultrafine spheres penetrate into the 100~180 micrometer groove, solidify to form a low thermal conductivity in-situ insulation wall, tightly wrap the stepped outward cantilever, eliminate micro-cracks and cavitation on the chip sidewall, and lock the Z-axis asymmetric thermal deformation.

[0128] The in-situ curing of the transverse heat insulation groove forms an insulating wall. The molten molding compound flows fully into the transverse through-hole solder resist isolation groove 400, which is only 100 to 180 micrometers wide, and achieves in-situ curing. The cured protective layer material has an inherent thermal conductivity of only 0.8 to 1.2 watts per meter Kelvin, forming a solid low thermal conductivity insulating block on the surface of the substrate 100, which completely isolates the transverse heat conduction path between the control chip and the first flash memory bare chip 301.

[0129] The anti-impact wire flow protection of the three-dimensional undulating lead mesh utilizes the high flow and lubricity of multi-peak spherical micro powder, combined with the three-dimensional undulating space formed by the alternating heights of the grounding shield lead and the data signal lead, so that the molten molding compound is dispersed into a microscopic multi-channel laminar flow when flowing through the lead arrangement surface; the lateral local resistance of the fluid to a single metal lead is reduced by more than 40%, completely avoiding the metal lead from lateral collapse, parallel contact, or arc apex collapse under the injection molding impact, so that the geometric skeleton of the three-dimensional shield lead with alternating heights retains 100% of its original shape after injection molding and curing.

[0130] IV. Precise matching of thermal expansion coefficients and isotropic stress relaxation mechanism.

[0131] The overall encapsulation protective layer 600 possesses precisely controlled thermodynamic properties after curing to balance the longitudinal and lateral internal stresses of the multi-chip system. The thermophysical property parameters are configured as follows: Glass transition temperature: The curing glass transition temperature of the overall encapsulation protective layer 600 is limited to 145 degrees Celsius to 175 degrees Celsius, which is higher than the maximum operating temperature of the chip under industrial and enterprise-level conditions (125 degrees Celsius). This ensures that the material always maintains a stable glass state with high elastic modulus throughout the entire operating temperature range and does not soften at high temperatures. Linear thermal expansion coefficient matching: Below the glass transition temperature, the linear thermal expansion coefficient of the protective layer is strictly controlled to be between 7 and 10 × 10⁻⁶ per Kelvin. This value is precisely between that of the single-crystal silicon chip (approximately 3 × 10⁻⁶ per Kelvin) and the multilayer insulating circuit packaging substrate 100 (approximately 12 to 15 × 10⁻⁶ per Kelvin), acting as an intermediate buffer medium for the thermodynamic expansion of the entire package assembly.

[0132] The stress self-relaxation of the embedded microsiloxane elastomer consists of micron-sized organosiloxane modified elastic microspheres (average particle size of one to three microns) uniformly dispersed within the resin matrix at a mass ratio of two to five percent. When the packaging device is subjected to thermal shock, the dispersed elastic microspheres absorb the internal stress generated by the shrinkage of the matrix through local micro-elastic deformation, preventing the formation of inward compressive shear stress cracks at the corners of the cantilever ends of the stepped stacked chip by the bulk molding plastic, thus protecting the multilayer silicon bare chip itself from brittle chipping.

[0133] V. The overall protection and reliability of the resulting technology.

[0134] The overall encapsulation protective layer 600 achieves significant overall mechanical and environmental protection performance through the precise interlocking of the aforementioned material formulation, geometry, and internal microstructures. The excellent flatness and anti-warping performance of the entire chip rely on the low linear thermal expansion coefficient brought about by the high filler content, as well as the uniform stress coating of the substrate 100 and each layer of bare chips. After the multi-chip packaging device undergoes a high-temperature reflow soldering process of 260 degrees Celsius, the coplanarity warping error of the entire device bottom surface is strictly controlled within 30 micrometers, completely eliminating the defects of poor soldering or short circuit of solder bridge during surface mounting.

[0135] Extremely high resistance to moisture and heat interface peeling reliability; the resin and modified spherical silica micro powder form a highly dense molecular network, making the water absorption rate of the cured body less than 0.25 percent in high temperature and high humidity environments. The tightly encapsulated molding compound is firmly anchored to the stepped cantilever micro-adhesive corner and the 100% solder mask edge of the substrate, completely eliminating the delamination micro-cracks at the interfaces of various materials inside the package, ensuring that the device can successfully pass the stringent high temperature and high humidity moisture sensitivity level 1 (highest level) reliability test.

[0136] The unexpected technical effects achieved by this application are as follows: This technical solution, through the organic combination of the above four dimensions, achieves the following synergistic and significant technical effects without adding external metal heat dissipation components or increasing the package thickness (the overall thickness remains within the standard specification of 1.2 mm): Significant reduction in interface shear stress concentration: Relying on the mechanical dispersion effect of the 100 hexagonal honeycomb micro-blind holes on the substrate and the longitudinal variable modulus adhesive film, the peak value of the maximum interface shear stress at the edge of the bottom bare chip in the multilayer stacked structure is significantly reduced by more than 40% when subjected to high temperature operation, completely eliminating the micro-peeling defect of the chip bonding insulating film at the cantilever edge on the outside of the step.

[0137] A qualitative leap in high-frequency signal integrity and crosstalk suppression: The spatially staggered three-dimensional lead arrangement reconstructs the electromagnetic coupling path in free space, reducing the differential capacitance crosstalk noise between adjacent leads to below -38 dB during high-frequency, high-speed data transmission (transmission rates exceeding 2400 Mbps). Even under severe temperature shocks, the signal eye diagram jitter amplitude caused by minute thermal displacements of the leads is reduced by more than 70%, ensuring high fidelity for high-density data reading and writing.

[0138] The lifespan and structural reliability under harsh operating conditions are multiplied: The 400 transverse solder mask isolation groove isolates the heat flow from the control chip to the memory bare chip in the transverse baking process. Combined with the longitudinal temperature gradient compensation, it completely eliminates the fatigue fracture of microcracks at the root of the bonding wires of the underlying flash memory bare chip, which increases the fatigue life of the whole machine by more than three times under the extremely harsh temperature cycling test of industrial grade (minus 40 degrees Celsius to 125 degrees Celsius).

[0139] The five structural layers constructed in this technical solution are not simply a stacking of components, but rather a bottom-up, interconnected physical collaborative closed loop built from five dimensions: "thermal field source blocking, interface stress relief, longitudinal deformation synchronization, spatial electromagnetic shielding, and global dielectric anchoring," targeting the chain failure mechanism of "intrinsic temperature difference field, local shear stress concentration, micro-displacement at the lead root, and abrupt change in high-frequency electromagnetic crosstalk" in multi-chip stacked flash memory devices.

[0140] The following details the inherent logical relationships between these five structural levels and the engineering mechanisms that constitute an organic whole: I. Overall Logic Closed Loop: Multi-physics Cascade Suppression Network from Heat Source to Signal.

[0141] The logical progression between the five levels is as follows: [Heat Source Layer] Layer Two: Planar thermal field physical isolation pathway (blocking lateral heat flow and reducing temperature rise of the bottom layer); After removing external heat from baking: [Substrate Interface] Level 1: Microscopic multi-directional strain-dissipating structure (six-directional honeycomb blind holes decompose the residual concentrated stress in the bottom layer); After stabilizing the underlying physical base: [Vertical Stacking] Layer 3: Variable Elastic Modulus Chip Bonding Layer System (Modulus decreases from bottom to top along the Z-axis, achieving synchronous high-temperature deformation) After completely eliminating the warping at the end of the stepped cantilever: [Electrical Interconnection] Level 4: Three-dimensional electromagnetic shielding lead network (constructing a pseudo-coaxial microcavity with varying spatial heights on a stable cantilever pad); After establishing the precise internal topology: [System Encapsulation] Layer 5: Overall Encapsulation Protective Layer 600 (Multi-peak microspheres with no voids, in-situ cured thermal insulation wall and locked three-dimensional leads).

[0142] II. The progressive synergy and causal coordination among the five structural levels.

[0143] 1. Synergy between Level 2 and Level 1 in "source heat interception and base unloading" (thermal-powered foundation linkage).

[0144] Logical connection: Level 2 provides a safe operating temperature boundary for Level 1, while Level 1 performs microscopic mechanical resolution on the residual thermal expansion after the flow is diverted from Level 2.

[0145] Physical mechanism: The storage control chip 200 is a high-heat logic operation unit. If its heat is conducted laterally along the surface of the substrate 100 to the stepped stacked storage area, the bottom first flash memory bare chip 301 will suffer a severe local additional temperature rise. Layer 2 (horizontal through solder mask slots and vertical thermal vias) acts as a "heat flow cut-off gate", forcing the heat of the control chip to be directly discharged vertically to the heat dissipation solder balls on the bottom surface of the substrate 100, thereby reducing the temperature rise of the sidewall of the bottom memory chip by 12 to 18 degrees Celsius. Based on this cooling, layer one (the hexagonal honeycomb micro-blind vias on the surface of substrate 100) further plays a role: the residual planar thermal expansion of the first flash memory bare chip 301 due to its own operation is confined within tens of thousands of discrete hexagonal micro-pillars and evenly dispersed in six symmetrical directions, thereby completely eliminating the occurrence of destructive shear stress concentration peaks at the edge of the bottom cantilever.

[0146] 2. Spatial progression from "planar stress relief to vertical deformation synchronization" between Level 1 and Level 3 (mechanical extension from two-dimensional to three-dimensional).

[0147] Logical connection: Level 1 solves the two-dimensional planar shearing and peeling between the bottom chip and the substrate 100, while Level 3 uses this as a rigid foundation to solve the longitudinal deformation mismatch along the Z-axis height direction of the entire three-dimensional multi-layer ladder.

[0148] Physical mechanism: Layer 1 is firmly anchored to the underlying high-rigidity adhesive film through honeycomb micro-blind holes, creating a flat and rigid base with zero micro-slippage for the entire multilayer stack. Layer 3 (variable elastic modulus film with longitudinal step changes) closely follows Layer 1: In response to the temperature field that naturally decays from bottom to top within the encapsulation, the bottom layer uses a high-modulus, low-expansion high-filler film (thickness of 18 to 22 micrometers), and the top layer uses a low-modulus, high-flexibility ultra-thin film (thickness of 7 to 9 micrometers). This gradient design ensures that the expansion and contraction of the "low-expansion coefficient adhesive film in the high-temperature zone of the bottom layer" and the "high-elasticity adhesive film in the relatively low-temperature zone of the top layer" are precisely matched under actual working temperature rise, enabling the four to sixteen layers of cantilever steps to achieve equal and coordinated deformation. At the same time, the rounded micro-adhesive corners at the root of the cantilever completely eliminate stress singularities and bending warping at the sharp corners of each chip layer.

[0149] 3. Functional mapping from "rigid mechanical support to spatial electromagnetic protection" in Level 3 and Level 4 (mechanical stability to electrical fidelity).

[0150] Logical connection: Layer 3 provides a robust physical stiffness platform for the wire bonding of Layer 4 and eliminates cantilever chatter, while Layer 4 achieves high-frequency, low-crosstalk transmission under this geometric steady state.

[0151] Physical mechanism: When performing micron-level fine metal wire bonding, if the adhesive film under the chip softens at high temperature, the cantilever pads will undergo microscopic sinking and bouncing under ultrasonic pressure, resulting in poor soldering at the root of the wire; the bottom high-modulus adhesive film of layer 3 provides rigid mechanical support for the pads, ensuring that the spatial coordinates of each layer of pads are absolutely accurate. On this geometrically stable pad layout, layer four (a three-dimensional lead mesh with alternating heights and depths) is precisely achieved: the high-level grounding lead spans above the data signal lead at a height of 35 to 55 micrometers, and works in conjunction with the substrate 100 ground layer to construct an inverted trapezoidal semi-enclosed virtual coaxial shielding cavity. At this point, it is precisely because layers one, two, and three eliminate the micron-level thermal displacement at the edge of the cantilever that the relative spatial gap between the high and low leads in layer four remains constant (not less than 25 microns) under alternating hot and cold conditions, completely sealing off high-frequency parasitic capacitance crosstalk and eye diagram jitter between data channels.

[0152] 4. Level 5 serves as the physical integration (material fusion and structural solidification) of "global media anchoring and system closure".

[0153] Logical connection: Level 5 is not a passive shell, but a key medium phase that actively participates in and simultaneously solidifies and empowers Levels 2, 3 and 4.

[0154] Physical mechanism: Level 2: The multi-peak spherical silica filler and low-viscosity epoxy resin melt used in Level 5 completely wet and fill the transverse weld barrier 400 of Level 2 during injection molding, and solidify in situ to form a "solid thermal insulation wall" with low thermal conductivity, so that the thermal insulation function of Level 2 is finally materialized. Level 4: The rolling lubrication effect of submicron-level ultrafine silica microspheres in Level 5, combined with the flow channel characteristics of discrete distribution of high and low leads in Level 4, ensures that the molten molding compound does not generate unidirectional extrusion force when flowing through the three-dimensional lead mesh, strictly controlling the wire offset rate to within 5%, and 100% "solidifying and locking" the three-dimensional shielding topology of Level 4. Overall integration: The low linear thermal expansion coefficient (7 to 10 × 10 to the power of negative 6 per Kelvin) of the fifth layer after curing is precisely between that of the silicon chip and the substrate 100. It rigidly encapsulates the honeycomb substrate 100 of the first layer, the variable modulus stepped chip of the third layer, and the three-dimensional lead mesh of the fourth layer into an ultra-thin impact-resistant entity with symmetrical force and a top surface coplanarity warpage of less than 30 micrometers.

[0155] III. The indivisibility of the scheme (why each part is indispensable).

[0156] If any layer in this system is arbitrarily removed, the balance of the entire packaging system will be instantly disrupted, triggering a chain reaction of failures: If layer two (heat insulation groove) is missing: the high heat of the control chip will overflow laterally, directly breaking through the temperature control threshold of layer one and layer three bottom layers. The bottom adhesive film will soften due to excessive heat, leading to the failure of the honeycomb stress relief structure. If layer one (honeycomb blind via) is missing: the bottom chip edge will generate a unidirectional concentrated shear stress peak again, the chip adhesive film will undergo micro-peeling, the peeling displacement will pull the lead root of layer four upward, resulting in lead micro-cracks and high-frequency open circuit. If layer three (variable modulus system) is missing: If a uniform film is used for the entire layer, the temperature difference between the upper and lower layers will cause deformation to lose synchronization, the stepped cantilever will undergo macroscopic warping, the height difference between the high and low lead wire spaces originally set in layer four will be deformed and distorted, the three-dimensional shielding cavity will collapse, and high frequency crosstalk will be triggered. If layer four (three-dimensional undulating leads) is missing: even if the mechanical structure is very stable, when the storage read and write speed exceeds 2,400 megabits per second, the flat, long-distance parallel leads will still generate serious inherent capacitive crosstalk, which cannot meet the enterprise-level high-speed read and write requirements. If layer five (multi-peak gradation protective layer) is missing: the standard-sized plastic cannot completely fill the gaps between the micro-deep grooves and the high-density three-dimensional leads, resulting in micro-pores and severe wire breakage, leading to the failure of the layer two insulation wall and short circuits in the layer four lead connections.

[0157] In summary, these five structural levels extend in physical space from nano / micro-scale material components (multi-peak microspheres, variable modulus crosslinking), micro-interface topology (regular hexagonal honeycomb blind holes, rounded micro-adhesive corners), and millimeter-scale functional slotting (solder resist heat insulation grooves, thermally conductive vias) all the way to macro-scale three-dimensional networks (three-dimensional undulating lead mesh, overall molded protective body). Thermally, they achieve "source blocking-gradient balance"; mechanically, "multi-directional decomposition-longitudinal synchronization"; and electrically, "rigid base-three-dimensional shielding," together forming a highly self-consistent and causally clear organic whole.

[0158] It should be understood that the methods and devices disclosed in the several embodiments provided in this application can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of modules or units is merely a logical functional division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

[0159] If the integrated units in the other embodiments described above are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0160] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A 3D NAND flash memory packaging device, characterized in that, The 3D NAND flash memory packaging device includes: substrate; A storage control chip is disposed in a first region on the upper surface of the substrate; A stepped-stacked flash memory storage component is disposed in a second region on the upper surface of the substrate. The stepped-stacked flash memory storage component includes at least two bare flash memory chips, which are staggered and stacked in the second region along the vertical direction of the upper surface of the substrate. The storage control chip and the stepped-stacked flash memory storage component are encapsulated on the upper surface of the substrate by an integral encapsulation protective layer. A thermal isolation strip is provided between the first region and the second region of the substrate; a multi-directional strain relief structure is provided in the first adhesive layer and the solder resist insulating film between the stepped stacked flash memory storage component and the upper surface; The multi-directional strain resolution structure includes: Several regular hexagonal blind holes are arranged in a periodic honeycomb pattern, and adjacent regular hexagonal blind holes are isolated from each other by a common solder resist insulating wall; The first adhesive layer forms a regular hexagonal elastic adhesive pillar insert inside each of the aforementioned regular hexagonal blind holes; Adjacent flash memory bare chips are bonded together by a second adhesive layer. The multiple second adhesive layers are distributed in a regular step-like gradient in terms of Young's modulus, initial thickness and inorganic filler mass ratio along the longitudinal stacking direction from the substrate toward the stepped stacked flash memory storage component. Each of the bare flash chips has a chip pad arrangement area on its edge. The chip pad arrangement area and the peripheral substrate connection pads corresponding to the upper surface of the substrate are vertically interconnected in a three-dimensional manner through metal bonding wires.

2. The 3D NAND flash memory packaging device according to claim 1, characterized in that, The thermal insulation strip includes: Solder resist isolation groove, the solder resist isolation groove being formed on the solder resist insulating film on the upper surface of the substrate; A surface-layer thermally conductive copper foil strip is disposed at the bottom of the solder resist isolation groove; A vertical thermally conductive via array is disposed below the surface thermally conductive copper foil strip and penetrates the multilayer insulating medium of the substrate, directly connecting to the grounded metal heat sink layer at the bottom of the substrate.

3. The 3D NAND flash memory packaging device according to claim 2, characterized in that, The solder mask isolation groove is distributed in a straight line or a slight arc along the boundary line between the first region and the second region, and its lateral extension length on the horizontal plane is greater than the adjacent side length of the storage control chip and the lowest-level flash memory bare chip among the at least two flash memory bare chips. The opening width of the weld resist isolation groove is between 100 micrometers and 180 micrometers. The solder resist isolation groove penetrates the solder resist insulating film on the upper surface of the substrate until the surface thermally conductive copper foil strip is completely exposed; The opening edges of the solder resist insulating film at both ends of the solder resist isolation groove have a rounded chamfered structure.

4. The 3D NAND flash memory packaging device according to claim 2, characterized in that, The surface thermally conductive copper foil strip has the same width as the groove of the solder resist isolation groove, and the thickness of the surface thermally conductive copper foil strip is 12 to 18 micrometers.

5. The 3D NAND flash memory packaging device according to claim 2, characterized in that, The diameter of each vertical thermally conductive via in the vertical thermally conductive via array is between 50 and 80 micrometers, and the thickness of the copper plating layer on the inner wall of the via is not less than 15 micrometers, or the inside of the via is completely filled with a highly thermally conductive metal paste.

6. The 3D NAND flash memory packaging device according to claim 1, characterized in that, The depth of each of the regular hexagonal blind holes is less than the overall coating thickness of the solder resist insulating film, and the bottom of each of the regular hexagonal blind holes is disposed on the solder resist insulating film.

7. The 3D NAND flash memory packaging device according to claim 1, characterized in that, The at least two flash memory bare chips include a first flash memory bare chip, a second flash memory bare chip, a third flash memory bare chip, and a fourth flash memory bare chip that are staggered and stacked vertically along the upper surface of the substrate; the second flash memory bare chip is bonded to the first flash memory bare chip through a first second adhesive layer, the third flash memory bare chip is bonded to the second flash memory bare chip through a second second adhesive layer, and the fourth flash memory bare chip is bonded to the third flash memory bare chip through a third second adhesive layer. The Young's modulus of the first second adhesive layer is greater than that of the second second adhesive layer, and the Young's modulus of the second second adhesive layer is greater than that of the third second adhesive layer. The initial thickness of the first second adhesive layer is greater than the initial thickness of the second second adhesive layer, and the initial thickness of the second second adhesive layer is greater than the initial thickness of the third second adhesive layer; The inorganic filler mass ratio of the first second adhesive layer is greater than that of the second second adhesive layer, and the inorganic filler mass ratio of the second second adhesive layer is greater than that of the third second adhesive layer.

8. The 3D NAND flash memory packaging device according to claim 1, characterized in that, The chip pad arrangement area is a cantilevered staircase, and the second adhesive layer forms an arc-shaped adhesive corner structure at the inner corner of the root of the cantilevered staircase.

9. The 3D NAND flash memory packaging device according to claim 1, characterized in that, The metal bonding leads are divided into lead unit groups. Each lead unit group includes a first ground shield lead arranged in a horizontal space, two adjacent high-frequency data signal leads, and a second ground shield lead. Adjacent lead unit groups share a ground shield lead located at the boundary. The data signal lead trajectory is as follows: each data signal lead adopts a low arc spatial orientation, and after being led out from the chip pad arrangement area, it gently slopes downward to connect to the outer substrate connection pad. The vertical net height between the highest point of its spatial arc and the upper surface of its corresponding flash memory bare chip is 60 to 80 micrometers. The grounding shield lead trajectory is as follows: each grounding shield lead adopts a towering arch bridge-shaped spatial orientation, and after being led out from the chip pad arrangement area, it extends upward at a preset starting angle and then tilts downward to cross over to the outer substrate connection pad. The vertical net height between the highest point of its spatial arc and the upper surface of its corresponding flash memory bare chip is 95 micrometers to 135 micrometers. In the longitudinal projection direction perpendicular to the substrate, the highest point of the spatial arc of each grounding shield lead is stably 35 to 55 micrometers higher than the highest point of the spatial arc of the adjacent data signal lead. The grounding shielding lead forms a spatial semi-enclosed virtual coaxial electromagnetic protection cavity.

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