Chip package adaptive bonding structure and method based on 4D printing responsive functional interlayer and packaged device

Abstract

The application discloses a chip packaging self-adaptive bonding structure and method based on a 4D printing response type functional interlayer and a packaged device, and comprises a first to-be-bonded component, a second to-be-bonded component and a 4D printing response type functional interlayer. The 4D printing response type functional interlayer comprises a response base material, and a functional filler and a bonding active component embedded in or printed in a partition in the response base material. The functional filler is distributed in the response base material in a region, forming a plurality of functional partitions. The functional partitions comprise at least two of an electrically-conductive bonding area, a heat-conducting enhancement area, a stress buffering area, a deformation compensation area, an insulating isolation area and a sensing monitoring area. The interlayer undergoes preset deformation, modulus change, electrically-conductive phase lapping or heat-conducting path formation under the stimulation of heat, pressure, an electric field, light or a magnetic field, so as to realize warping compensation of a bonding interface, low-cavity interconnection, stress release and quality monitoring.

Description

Technical Field

[0001] This invention relates to the fields of advanced electronic packaging, wafer-level bonding, heterogeneous integration, chiplet packaging, 4D printed functional materials, and in-situ monitoring of packaging interfaces. Specifically, it relates to a chip packaging adaptive bonding structure, method, and packaging device based on a 4D printed responsive functional intermediate layer. In particular, it relates to a structure, method, and packaging device that forms a multi-material partitioned responsive functional intermediate layer between two components to be bonded, and utilizes the deformation compensation, conductive interconnection, thermal conductivity enhancement, stress buffering, and monitoring signal evolution of this intermediate layer during the bonding process to achieve adaptive bonding. Background Technology

[0002] With the development of chip integration, wafer-level packaging, glass interposer packaging, silicon interposer packaging, and microelectromechanical systems (MEMS) packaging, the packaging bonding interface is no longer just a simple mechanical connection interface, but also undertakes functions such as electrical connection, heat conduction, stress relief, and long-term reliability assurance. In actual packaging processes, the first and second components to be bonded typically exhibit wafer warpage, substrate warpage, pad height differences, microbump coplanarity errors, local roughness differences, and thermal expansion coefficient mismatches. These differences can lead to problems such as localized non-contact areas, edge voids, pad overpressure, interface delamination, and stress transfer to sensitive structures.

[0003] Existing anisotropic conductive films can achieve conductive interconnection in the thickness direction, but their conductive particles are usually uniformly dispersed within the film layer. The film thickness, modulus, and particle distribution are difficult to spatially adjust based on local warpage or pad height differences. When both raised and recessed regions exist at the bonding interface, a uniform film layer often needs to compromise between conductivity reliability and avoiding overvoltage, making it difficult to simultaneously achieve low void ratio and low-damage bonding.

[0004] Existing underfill adhesives, conductive adhesives, or low-modulus buffer adhesives can alleviate thermal cycling stress to some extent. However, these materials are typically used as uniform coatings or post-fill materials, and filling, curing, and bonding often belong to different processes. Multi-processing increases alignment errors and the number of interfaces, and also makes it difficult to obtain real-time information on localized interface pressure, contact resistance, gap changes, or crack initiation in the early stages of packaging. For structures such as MEMS sensitive diaphragms, resonant beams, thin core particles, and glass transition plates, simply reducing the overall modulus may sacrifice interconnect support strength and thermal conductivity.

[0005] 4D printing materials, capable of changing shape, size, modulus, or functional state over time under external stimuli, have shown application potential in shape memory structures, soft actuators, and functionally graded components. However, most existing 4D printing solutions focus on macroscopic structural deformation or the smart material itself, with less emphasis on in-layer co-design for microscale interconnect locations, warpage compensation, thermal paths, and interface monitoring requirements in chip packaging bonding interfaces. Using 4D printing materials merely as ordinary adhesive layers or buffer layers fails to create a substantial technological contribution distinct from existing conductive adhesives, underfills, or sensor patches.

[0006] Therefore, it is necessary to propose a responsive functional intermediate layer for 4D printing oriented towards chip packaging bonding interfaces to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to address the problems existing in the prior art by providing a chip packaging adaptive bonding structure, method, and packaging device based on a 4D printed responsive functional intermediate layer. This overcomes the shortcomings of traditional uniform conductive adhesive, underfill, anisotropic conductive film, and post-mounted sensors in chip packaging bonding interfaces. It enables multi-material partition printing based on measured surface morphology and interconnect layout, integrates conductivity, thermal conductivity, stress buffering, deformation compensation, insulation isolation, and in-situ monitoring functions within the same bonding interface, and achieves adaptive bonding through stimulus response and monitoring feedback during the bonding process.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first invention provides a chip packaging adaptive bonding structure based on a 4D-printed responsive functional intermediate layer, comprising a first component to be bonded, a second component to be bonded, and a 4D-printed responsive functional intermediate layer disposed between the first component to be bonded and the second component to be bonded; the 4D-printed responsive functional intermediate layer comprises a responsive matrix material, and functional fillers and bonding active components embedded in or partitionedly printed in the responsive matrix material; the responsive matrix material is used to generate a preset deformation, volume change, modulus change, or shape recovery under external stimuli; the functional fillers are distributed regionally within the responsive matrix material to form multiple functional zones; the functional zones include at least two of the following: conductive bonding zones, thermally enhanced zones, stress buffer zones, deformation compensation zones, insulating isolation zones, and sensing monitoring zones.

[0009] Furthermore, the multiple functional zones are arranged side by side in the planar direction, layered in the thickness direction, or form a three-dimensional gradient distribution in both the planar and thickness directions; at least one functional zone has a thickness, porosity, equivalent elastic modulus, conductive filler content, thermally conductive filler content, or stimulus response threshold that are different from those of adjacent functional zones.

[0010] Furthermore, the conductive bonding area is provided corresponding to the pads, microbumps, metal pillars or redistribution ports of the first and second components to be bonded, and contains nano-silver, nano-copper, silver-coated copper particles, low-melting-point alloy particles, anisotropic conductive particles, conductive carbon materials or combinations thereof.

[0011] The thermal conductivity enhancement region is set in the area corresponding to the heat source projection area of ​​the chip or the high heat flux density area of ​​the power device, and contains boron nitride, aluminum nitride, aluminum oxide, diamond micro powder, silicon carbide, graphite sheets, graphene, metal particles or combinations thereof, and the thermal conductivity enhancement region forms a preferred heat conduction path along the thickness direction, radial direction or heat source to heat dissipation substrate direction.

[0012] The stress buffer is located at the chip edge, the corner of the adapter board, the area prone to interface peeling, the periphery of the MEMS sensitive structure, or the thermal expansion mismatch area, and the equivalent elastic modulus of the stress buffer is lower than the equivalent elastic modulus of the conductive bonding area or the thermally enhanced area.

[0013] The deformation compensation zone is set for the local low-recessed area, warped area, pad height difference area or roughness difference area of ​​the interface to be bonded, and has an initial thickness, porosity, shape recovery amount, thermal expansion response amount and / or pressure-induced flow capacity greater than the adjacent area.

[0014] Furthermore, the sensing and monitoring area includes an in-situ monitoring unit formed synchronously during the 4D printing process. The in-situ monitoring unit includes a piezoresistive sensing grid, a capacitive sensing unit, a thermistor unit, a conductive crack monitoring line, a bridge strain unit, or a combination thereof, used to collect pressure, temperature, strain, resistance, capacitance, and / or interface integrity signals during the bonding process. The in-situ monitoring unit is formed in the same multi-material printing process as the response matrix material and the functional filler, and the output signal of the in-situ monitoring unit corresponds to the deformation, modulus change, local gap change, and / or conductive phase connection state of the response matrix material.

[0015] The responsive matrix material includes shape memory polymers, thermally responsive polymers, photoresponsive polymers, liquid crystal elastomers, thermoplastic resins, thermosetting resins, epoxy resins, polyimides, polyurethanes, silicone rubbers, or composite materials thereof.

[0016] The first component to be bonded and the second component to be bonded are each independently selected from chips, chips, wafers, silicon interposers, glass interposers, ceramic substrates, organic packaging substrates, metallized substrates, flexible substrates, MEMS devices, power devices, or combinations thereof.

[0017] Secondly, a chip packaging adaptive bonding method based on a 4D-printed responsive functional intermediate layer is provided to realize the above-mentioned chip packaging adaptive bonding structure based on a 4D-printed responsive functional intermediate layer. The chip packaging adaptive bonding includes the following steps: The surface morphology, warpage state, interconnection position, and thermo-mechanical parameters of the first component to be bonded and the second component to be bonded are obtained; based on the obtained surface morphology, warpage state, interconnection position, and thermo-mechanical parameters, the interface to be bonded is divided into multiple functional regions; A multi-material printing path is generated based on multiple functional regions, and the 4D printed responsive functional intermediate layer is prepared with a printing accuracy of no more than 50 micrometers in positioning error. The 4D printed responsive functional intermediate layer is pre-cured, pre-crosslinked, pre-sintered, or pre-shaped to maintain the printed pattern and retain its ability to respond to subsequent stimuli. Align the first and second components to be bonded and apply pre-pressure; apply heat, pressure, electric field, light, magnetic field or a combination thereof to cause the 4D printed responsive functional intermediate layer to undergo preset deformation, modulus change, release of bonding active components, connection of conductive phase, formation of thermal conductive pathways and / or curing reaction.

[0018] Furthermore, the surface morphology and the warpage state are obtained by white light interferometry, laser profilometry, confocal microscopy, wafer warpage measurement, or three-dimensional profile reconstruction, respectively. Based on the target bonding gap, allowable interface stress, and pad position matrix, the target thickness, target modulus, and target response displacement of the 4D printed responsive functional intermediate layer at each coordinate position are determined.

[0019] Furthermore, the pre-curing, pre-crosslinking, pre-sintering, or pre-shaping treatment temperatures are from 40°C to 160°C, and the time is from 30 seconds to 30 minutes; when photocuring is used for pre-treatment, the photocuring light energy density is from 50 mJ / cm² to 2000 mJ / cm², and the degree of curing after pre-treatment is lower than that of the fully cured state.

[0020] Furthermore, the bonding temperature in the adaptive bonding process is 60°C to 250°C, the bonding pressure is 0.05MPa to 30MPa, and the holding time is 1 second to 60 minutes; wherein, when the second component to be bonded is an organic packaging substrate or a flexible substrate, the bonding temperature is 60°C to 180°C.

[0021] Furthermore, the sensor monitoring area collects pressure, temperature, strain, resistance, or capacitance signals of the interface to be bonded; when the local pressure is lower than a preset threshold, the local bonding temperature is increased, the holding time is extended, or the bonding pressure is increased; when the local pressure is higher than the preset threshold, the bonding pressure is reduced, the heating rate is reduced, or the local heating path is adjusted; the sampling frequency of the sensor monitoring area is 10Hz to 1kHz; when the rate of change of the contact resistance of the conductive bonding area is less than 5% over at least 10 consecutive sampling periods, and the pressure, capacitance, or strain signals meet the uniformity condition, the bonding is determined to be complete.

[0022] Thirdly, a chip packaging device is provided, including the chip packaging adaptive bonding structure based on the 4D printing responsive functional intermediate layer as described above. The chip packaging device is a chip-integrated packaging device, a wafer-level packaging device, a three-dimensional stacked packaging device, a glass adapter plate packaging device, a MEMS sensor packaging device, a power electronics packaging device, a radio frequency packaging device, or a heterogeneous integrated packaging device.

[0023] Compared with the prior art, the beneficial effects of the present invention are: 1. The chip packaging adaptive bonding structure based on the 4D printing responsive functional intermediate layer transforms the warp state, interconnect position, heat source distribution, and stress-sensitive area of ​​the surface to be bonded into the printing path and material formulation, enabling the intermediate layer to undertake different functions according to spatial requirements within the same interface; in this way, local low-recessed areas can obtain greater deformation compensation capabilities, pads or micro-bump areas can obtain stable conductive interconnections, heat source projection areas can obtain lower thermal resistance paths, and chip edges or the periphery of MEMS sensitive structures can obtain low-modulus stress release capabilities; 2. Utilizing the spatial partitioning capability of multi-material 4D printing, the conductivity, thermal conductivity, buffering, compensation, and monitoring functions that originally required multiple independent layers or multiple processes can be transformed into functions that originally required multiple independent layers or multiple processes. 1. Measurement functions are integrated within the same bonding interface, reducing the number of interfaces and alignment errors; 2. Printing is performed on demand based on the actual measured warpage and surface morphology, enabling active compensation for local low-recessed areas and avoiding overpressure in local high-recessed areas, thus improving low-void bonding capability; 3. The conductive bonding area, thermally enhanced area, and stress buffer zone cooperate spatially, which can reduce thermal resistance and interface stress while ensuring interconnect reliability; 4. The in-situ monitoring unit is formed synchronously with the responsive intermediate layer, and the monitoring signal is directly related to the deformation and contact state of the intermediate layer, which is conducive to realizing real-time judgment and closed-loop control of the bonding process; 5. This invention is applicable to various scenarios such as chip integration, wafer-level packaging, glass adapter packaging, MEMS low-stress packaging, power electronic packaging, and heterogeneous integration packaging. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of an adaptive bonding structure for chip packaging based on a 4D-printed responsive functional intermediate layer according to the present invention. Figure 2This is a schematic diagram of the multi-material partition printing and sensing grid planar layout of the intermediate layer of the present invention; Figure 3 This is a schematic diagram illustrating the functional evolution of the responsive intermediate layer of the present invention before, during, and after bonding. Figure 4 This is a schematic diagram of the in-situ monitoring and bonding quality closed-loop control process of the present invention; Figure 5 This is a schematic diagram illustrating the mechanism of the present invention for identifying voids, overpressure, and delamination risks using multi-signal fusion; Figure 6 This is a schematic diagram illustrating the application of the present invention in chip integration, MEMS low-stress packaging, power device heat dissipation packaging, and three-dimensional stacked packaging.

[0025] In the figure: 100, first component to be bonded; 200, second component to be bonded; 300, 4D printed responsive functional intermediate layer; 310, responsive matrix material; 320, conductive bonding region; 330, thermally enhanced region; 340, stress buffer zone; 350, sensing and monitoring region; 360, bonding active component; 370, insulating isolation region; 380, deformation compensation region. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be noted that the terms "middle," "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] Example 1: A chip packaging adaptive bonding structure based on a 4D printing responsive functional intermediate layer is provided, combined with... Figure 1As shown, the 4D-printed responsive functional intermediate layer 300 includes a first component to be bonded 100, a second component to be bonded 200, and a 4D-printed responsive functional intermediate layer 300 disposed between the first component to be bonded and the second component to be bonded. The 4D-printed responsive functional intermediate layer 300 includes a responsive matrix material 310, and functional fillers and bonding active components 360 embedded in or partitioned within the responsive matrix material 310. The responsive matrix material 310 is used to generate a preset deformation, volume change, modulus change, or shape recovery under external stimuli. The functional fillers are distributed in regions within the responsive matrix material 310 to form multiple functional zones. The functional zones include at least two of the following: a conductive bonding zone 320, a thermally enhanced zone 330, a stress buffer zone 340, a deformation compensation zone 380, an insulating isolation zone 370, and a sensing monitoring zone 350.

[0029] This adaptive bonding structure for chip packaging based on a 4D-printed responsive functional intermediate layer does not simply add a functional material layer. Instead, it transforms the warpage state, interconnect positions, heat source distribution, and stress-sensitive areas of the surface to be bonded into the printing path and material formulation, allowing the intermediate layer to perform different functions according to spatial requirements within the same interface. In this way, localized low-recessed areas can achieve greater deformation compensation, pads or micro-bumps can achieve stable conductive interconnects, heat source projection areas can achieve lower thermal resistance paths, and chip edges or the periphery of MEMS sensitive structures can achieve low-modulus stress release capabilities.

[0030] The adaptive bonding structure for chip packaging utilizes the spatial partitioning capability of multi-material 4D printing to integrate electrical conductivity, thermal conductivity, buffering, compensation, and monitoring functions that originally required multiple independent layers or multiple processes into a single bonding interface, reducing the number of interfaces and alignment errors.

[0031] The conductive bonding region 320, the thermally enhanced region 330, and the stress buffer zone 340 are spatially coordinated, which can reduce thermal resistance and interface stress while ensuring interconnect reliability. The in-situ monitoring unit is formed synchronously with the responsive intermediate layer, and the monitoring signal is directly related to the deformation and contact state of the intermediate layer, which is conducive to realizing real-time judgment and closed-loop control of the bonding process.

[0032] In this embodiment, the 4D-printed responsive functional intermediate layer refers to an intermediate layer formed through multi-material 3D printing that undergoes controllable functional evolution over time and with external stimuli during the bonding process or service life. Before bonding, this intermediate layer exhibits a transferable or directly printable structure with a preset thickness, pattern, and material partitioning. During bonding, it responds to the matrix material by undergoing shape recovery, softening flow, local expansion, or modulus changes, actively compensating for interface warpage and height differences. The bonding active components form mechanical, electrical, or thermal connections in the corresponding areas of the pads or microbumps, and the thermally conductive filler forms a preferential heat transfer path under pressure and curing. After bonding, the intermediate layer continues to function as a stress buffer layer, a thermally conductive enhancement layer, and an interface health monitoring layer. The aforementioned "time dimension" is reflected in the dynamic evolution of the intermediate layer's deformation, conductivity, thermal conductivity, and signal state during the bonding process, rather than simply referring to the creation of a static structure using 3D printing.

[0033] Furthermore, the multiple functional zones are arranged side by side in the planar direction, layered in the thickness direction, or form a three-dimensional gradient distribution in both the planar and thickness directions; at least one functional zone has a thickness, porosity, equivalent elastic modulus, conductive filler content, thermally conductive filler content, or stimulus response threshold that are different from those of adjacent functional zones.

[0034] Furthermore, the conductive bonding region 320 is configured corresponding to the pads, microbumps, metal pillars, or redistribution ports of the first and second components to be bonded, and contains metal particles, anisotropic conductive particles, or low-melting-point alloy particles, such as nano-silver, nano-copper, silver-coated copper particles, low-melting-point alloy particles, anisotropic conductive particles, conductive carbon materials, or combinations thereof. To avoid short circuits in non-pad areas, the printing boundary of the conductive bonding region 320 can be recessed or expanded from the outer contour of the pad by 0 to 50 micrometers, and is surrounded by an insulating isolation region 370. For arrayed microbump structures, the conductive bonding region 320 can be a discrete island pattern; for redistribution ports, the conductive bonding region 320 can be a strip or ring pattern.

[0035] The thermal conductivity enhancement region 330 is set in the chip heat source projection area or the high heat flux density area of ​​the power device, and contains boron nitride, aluminum nitride, aluminum oxide, diamond micro powder, silicon carbide, graphite sheet, graphene, metal particles or combinations thereof, and the thermal conductivity enhancement region forms a preferred heat conduction path along the thickness direction, radial direction or heat source to heat dissipation substrate direction.

[0036] For chips with a small heat source area, the planar dimension of the thermally enhanced region 330 can be set to 1.0 to 2.0 times the projected area of ​​the heat source; for chips with dispersed heat source locations, the thermally enhanced region 330 can be configured as multiple island units, with low-modulus stress buffer material arranged between the island units. The thermally conductive filler can be preferentially oriented through nozzle shearing, magnetic field assistance, electric field assistance, or printing path control to reduce the thermal resistance in the thickness direction or in the direction from the heat source to the heat dissipation substrate.

[0037] The stress buffer 340 is disposed at the chip edge, the corner of the adapter board, the area prone to interface peeling, the periphery of the MEMS sensitive structure, or the thermal expansion mismatch area, and the equivalent elastic modulus of the stress buffer is lower than the equivalent elastic modulus of the conductive bonding area or the thermally enhanced area, so that the shear deformation caused by thermal cycling or curing shrinkage is preferentially released in the buffer.

[0038] In some embodiments, the stress buffer 340 employs a pore gradient structure, with higher porosity on the side closer to the chip edge and lower porosity on the side closer to the pads or conductive bonding areas. Porosity can be controlled by the print path spacing, nozzle extrusion rate, photopolymerization exposure dose, sacrificial phase content, or foaming particle content.

[0039] The deformation compensation region 380 is configured to correspond to localized low-lying areas, warped areas, pad height difference areas, or roughness difference areas of the interface to be bonded, and has a greater initial thickness, porosity, shape recovery, thermal expansion response, and / or pressure-induced flow capability than adjacent areas. The deformation compensation region 380 can have a larger initial thickness, higher porosity, greater shape recovery, or lower compressive modulus. When heat, pressure, or other external stimuli are applied, the deformation compensation region 380 undergoes shape recovery, volume compensation, or softening flow to fill local gaps and reduce the risk of voids. For locally protruding areas, a material with a smaller thickness or higher flow capability can be used to prevent pad collapse, core edge cracking, or damage to the MEMS structure.

[0040] Combination Figure 2 As shown, these functional zones can be arranged side-by-side in the planar direction, layered in the thickness direction, or form a three-dimensional gradient distribution with planar-thickness coupling. For example, a conductive bonding region 320 can be set in the pad array area, a thermally enhanced region 330 in the heat source projection area, a stress buffer zone 340 in the chip edge, a deformation compensation region 380 in the warp and depression area, an insulating isolation region 370 between conductive regions, and a piezoresistive or capacitive sensing grid at key locations. These zones can be generated by multi-material printing paths in the same coordinate system, thereby reducing multi-layer alignment errors.

[0041] Furthermore, the sensing and monitoring area 350 includes an in-situ monitoring unit formed synchronously during the 4D printing process. The in-situ monitoring unit includes a piezoresistive sensing grid, a capacitive sensing unit, a thermistor unit, a conductive crack monitoring line, a bridge strain unit, or a combination thereof, for acquiring pressure, temperature, strain, resistance, capacitance, and / or interface integrity signals during the bonding process. The in-situ monitoring unit is formed in the same multi-material printing process as the response matrix material and the functional filler, and the output signal of the in-situ monitoring unit corresponds to the deformation, modulus change, local gap change, and / or conductive phase connection state of the response matrix material.

[0042] Its output signal directly reflects the local pressure, interfacial gap, contact resistance, temperature field, strain state, or crack / delamination risk of the intermediate layer. By correlating the monitoring signal with process parameters such as heating rate, holding time, local heating power, and overall pressure, a closed-loop control of bonding quality can be formed.

[0043] Furthermore, the responsive matrix material 310 includes shape memory polymers, thermally responsive polymers, photoresponsive polymers, liquid crystal elastomers, thermoplastic resins, thermosetting resins, epoxy resins, polyimides, polyurethanes, silicone rubbers, or composites thereof. The responsive matrix material 310 can serve as a continuous phase coating functional filler or as a supporting framework carrying different functional regions; the functional filler may include conductive fillers, thermally conductive fillers, piezoresistive fillers, thermistoric fillers, dielectric fillers, and insulating fillers; the bonded active component 360 may be metal nanoparticles, low-melting-point alloy particles, solder microparticles, reactive curing groups, or surface activators.

[0044] The first component to be bonded 100 and the second component to be bonded 200 are independently selected from chips, chips, wafers, silicon interposers, glass interposers, ceramic substrates, organic packaging substrates, metallized substrates, flexible substrates, MEMS devices, power devices, or combinations thereof. Preferably, the first component to be bonded 100 can be a logic chip, a memory chip, an RF chip, a power chip, a MEMS sensor chip, or a wafer; the second component to be bonded 200 can be a glass interposer, a silicon interposer, a ceramic substrate, an organic packaging substrate, a flexible substrate, another chip, or another wafer; pads, microbumps, metal pillars, redistribution ports, or metallized via ports can be provided on the first component to be bonded 100 and the second component to be bonded 200.

[0045] Example 2: A chip packaging adaptive bonding method based on a 4D printed responsive functional intermediate layer is provided to realize the above-mentioned chip packaging adaptive bonding structure based on a 4D printed responsive functional intermediate layer.

[0046] The adaptive bonding of the chip packaging includes the following steps: Step 1, Obtain information on the surfaces to be bonded: Obtain the surface morphology, warpage state, interconnection position, and thermo-mechanical parameters of the first component to be bonded and the second component to be bonded; Specifically, a white light interferometer, laser profilometer, confocal microscope, wafer warpage measurement equipment, or three-dimensional contour reconstruction system can be used to measure the surface height distribution of the first component to be bonded 100 and the second component to be bonded 200, obtaining height matrices H1(x,y) and H2(x,y). Based on the target bonding gap G0, allowable interface stress σallow, pad position matrix P(x,y), heat source position matrix Q(x,y), and sensitive structure position matrix M(x,y), the target thickness T(x,y), target modulus E(x,y), target thermal conductivity K(x,y), and target response displacement D(x,y) of the 4D printed responsive functional intermediate layer 300 at each coordinate position are calculated.

[0047] Step 2, perform functional area division: Based on the obtained surface morphology, warpage state, interconnection position and thermo-mechanical parameters, the interface to be bonded is divided into multiple functional areas; Specifically, the area corresponding to the pads or microbumps is divided into conductive bonding areas 320; the projection area of ​​heat sources or high-power circuits is divided into thermally enhanced areas 330; the chip edges, corners of the adapter board, the periphery of the MEMS film, or areas with large warping gradients are divided into stress buffer zones 340; the areas prone to local depressions, voids, or significant height differences are divided into deformation compensation areas 380; the areas between adjacent conductive areas are divided into insulation isolation areas 370; and the locations where pressure, gaps, cracks, or delamination need to be determined in real time are divided into sensing and monitoring areas 350.

[0048] Step 3, using multi-material 3D printing to prepare a 4D printed responsive functional intermediate layer 300: generate multi-material printing paths according to multiple functional regions, and prepare the 4D printed responsive functional intermediate layer with a positioning error of no more than 50 micrometers. Specifically, the printing method can be direct writing printing, inkjet printing, aerosol printing, digital light processing printing, stereolithography printing, extrusion printing, or a combination thereof; for densely packed micro-bump array areas, the printing positioning error is preferably no more than 50 micrometers; for higher density interconnection scenarios, the printing positioning error can be further controlled to no more than 10 micrometers; during the printing process, different nozzles, different inks, different exposure doses, or different printing paths can be selected according to different areas, so that the thickness, porosity, filler content, and response threshold can be spatially controlled to vary.

[0049] Step 4: After printing is completed, the 4D printed responsive functional intermediate layer is pre-cured, pre-crosslinked, pre-sintered or pre-shaped to maintain the printed pattern and retain its ability to respond to subsequent stimuli. Pretreatment temperatures can range from 40°C to 160°C, and times can range from 30 seconds to 30 minutes. When using a photocuring system for pre-curing, the light energy density can range from 50 mJ / cm² to 2000 mJ / cm². The purpose of pretreatment is not to completely cure the intermediate layer, but to give it the initial strength required for transfer, handling, and alignment, while retaining its ability to deform in response to subsequent stimuli. If pre-curing is over-cured, the intermediate layer will have difficulty compensating for local gaps during bonding; if pre-curing is insufficient, the printed pattern may collapse during alignment or pressure application. Therefore, the pre-curing window can be determined by differential scanning calorimetry, dynamic mechanical analysis, or sample compression recovery testing.

[0050] Step 5, perform alignment and stimulus-response bonding: Align the first component to be bonded and the second component to be bonded and apply pre-pressure; apply heat, pressure, electric field, light, magnetic field or a combination thereof to stimulate the 4D printed responsive functional intermediate layer to undergo preset deformation, modulus change, release of bonding active components, connection of conductive phase, formation of thermal conductive pathways and / or curing reaction; Specifically, the bonding temperature can be from 60°C to 250°C, the bonding pressure can be from 0.05MPa to 30MPa, and the holding time can be from 1 second to 60 minutes. When the second component to be bonded 200 is an organic packaging substrate or a flexible substrate, the bonding temperature is preferably controlled between 60°C and 180°C. When the second component to be bonded 200 is a glass transition plate, a silicon transition plate, or a ceramic substrate, a higher temperature range can be selected according to the material system. In this stage, the deformation compensation region 380 fills the recessed area, the conductive bonding region 320 forms a stable conductive path, the thermally enhanced region 330 forms a low thermal resistance path, and the stress buffer zone 340 absorbs interfacial shear deformation.

[0051] like Figure 3 As shown, the 4D responsive interlayer of this invention is not limited to a single shape change. Before bonding, the interlayer maintains a multi-material printing pattern and establishes thickness, modulus, and filler content distribution according to the interface to be bonded. During bonding, the interlayer undergoes shape recovery, softening flow, local expansion, conductive phase overlap, thermal pathway formation, and curing reaction under external stimuli. After bonding, the interlayer continues to perform functions such as conductive interconnection, thermal dissipation, stress release, and interface state monitoring. Because the function of the interlayer evolves with the bonding process, it differs from ordinary static conductive adhesive layers or static underfill layers.

[0052] In some embodiments, such as Figure 4As shown, the sensing monitoring area 350 is connected to the feedback controller to form a closed-loop control of bonding quality. The sensing monitoring area 350 may include a piezoresistive sensing grid, a capacitive sensing unit, a thermistor unit, a conductive crack monitoring line, or a bridge strain gauge unit. The two ends of the piezoresistive sensing grid can be connected to external test pads, and then to a bridge measurement circuit; the capacitive sensing unit may consist of an upper electrode and a lower electrode arranged opposite each other, separated by a response substrate material; the conductive crack monitoring line may be arranged in a serpentine pattern along the chip edge, the corner of the adapter board, or a high-stress area. Multiple monitoring units can be read sequentially through a multiplexing circuit to form an interface pressure distribution map, a gap distribution map, or a crack risk map.

[0053] The sampling frequency of the in-situ monitoring unit can range from 10 Hz to 1 kHz. Before bonding begins, the initial resistance R0, initial capacitance C0, or initial temperature T0 is recorded. During bonding, real-time resistance Rt, real-time capacitance Ct, real-time temperature Tt, and real-time strain εt are recorded, with ΔR / R0, ΔC / C0, temperature rise rate, or strain change rate used as judgment indicators. When the piezoresistive change in a certain area is below a threshold, it can be determined that there may be no contact or voids in that area; when the piezoresistive change is too large or the capacitance gap signal rises rapidly, it can be determined that there may be overvoltage in that area; when the conductive crack monitoring line shows a step change or open circuit, it can be determined that there is a risk of cracking or delamination at the interface.

[0054] Based on monitoring results, the feedback controller can adjust the heating rate, local heating power, overall bonding pressure, local pressure distribution, or holding time. If the pressure signal in a certain area remains below the target value, the holding time is extended, the local heating temperature in that area is increased, or the overall bonding pressure is appropriately increased. If the pressure signal in a certain area exceeds the target value, the heating rate is reduced, the pressure is decreased, or the local heating path is adjusted to avoid pad collapse, MEMS structure damage, or chip edge cracking. The bonding completion determination is no longer based solely on a fixed time or a fixed temperature, but also on the contact resistance of the conductive bonding area, the uniformity of the piezoresistive grid, and the capacitance gap signal. For example, when the contact resistance of the conductive bonding area changes by less than 5% over at least 10 consecutive sampling periods, and the difference between the maximum and minimum pressure signals is within the allowable range, the conductive interconnect and interface bonding can be determined to have reached a stable state.

[0055] like Figure 5As shown, the sensing monitoring area 350 can be used to identify voids, overpressure, and delamination risks. For local voids or unbonded areas, the piezoresistive signal is lower than that of adjacent areas, the capacitance signal is lower than that of the target range, and the contact resistance of the conductive bonding area may fluctuate. For local overpressure areas, the piezoresistive signal changes too much, the capacitance value rises rapidly, and there is a risk of collapse of local pads or microbumps. For cracked or delamination areas, the serpentine conductive monitoring line may show step resistance changes or open circuits, and the bridge strain unit may show discontinuous strain abrupt changes. By fusing multiple signals, the reliability of bonding quality judgment can be improved, avoiding misjudgments caused by a single temperature or time parameter.

[0056] To further describe the adaptive bonding structure and method for chip packaging, the following more specific embodiments are provided.

[0057] Example 3: Bonding a logic chip to a glass adapter plate. The first component to be bonded, 100, is a logic chip with dimensions of 10mm × 10mm, and the second component to be bonded, 200, is a glass adapter plate with a thickness of 300 micrometers to 700 micrometers. A redistribution layer and metal pads are provided on the surface of the glass adapter plate, and a corresponding micro-bump array is provided on the bottom of the chip. Contour measurement reveals a warpage difference of 5 to 30 micrometers between the central region and the edge of the glass adapter plate. To address this warpage difference, a deformation compensation region 380 with a thickness of 20 to 80 micrometers is printed in the recessed area, a support region with a thickness of 5 to 30 micrometers is printed in the relatively raised area, and a conductive bonding region 320 is printed at the corresponding position of the pads. The width of the conductive bonding region 320 can be 10 to 200 micrometers, and the filler mass fraction can be 20 wt.% to 80 wt.%.

[0058] In this embodiment, during bonding, preheating is first performed at 80°C to 120°C to soften the responsive matrix material 310 and induce an initial deformation response. Then, a pressure of 0.5MPa to 10MPa is applied at 120°C to 220°C and held for 30 seconds to 20 minutes. During bonding, the deformation compensation region 380 preferentially fills the edge or localized low-lying gaps caused by the warping of the glass transition plate. Metal particles in the conductive bonding region 320 form a continuous conductive path under pressure and temperature, and the thermally enhanced region 330 forms a low thermal resistance path in the core particle heat source projection area. The sensing and monitoring region 350 reads the local pressure and contact resistance in real time. If the contact resistance decreases significantly slower in a certain area than in other areas, the holding time is extended or the local heating temperature is increased. Compared to a uniform conductive adhesive layer, this embodiment can reduce the probability of simultaneous edge non-contact and center overpressure.

[0059] Example 4: Low-stress packaging for MEMS sensors. The first component to be bonded 100 is a MEMS sensor chip with a pressure diaphragm or resonant beam, and the second component to be bonded 200 is a ceramic substrate or silicon substrate. The 4D-printed responsive functional intermediate layer 300 is distributed in a ring, avoiding the central region of the MEMS sensitive diaphragm, and bonding is formed only at the chip edge and electrode region. The ring stress buffer 340 is made of a low-modulus elastomer or shape memory polymer, whose equivalent elastic modulus is lower than that of the conductive bonding region 320 and the substrate material; the electrode region is a conductive bonding region 320 containing silver particles or low-melting-point alloy particles; a piezoresistive grid is set at the chip edge as a packaging stress monitoring unit. After bonding, the shear deformation generated during thermal cycling is preferentially absorbed by the ring stress buffer 340, reducing the degree of stress transmission to the MEMS sensitive diaphragm.

[0060] Example 5: Thermal Enhancement Bonding in Power Electronic Packaging. The first component to be bonded 100 is a power chip or power module die, and the second component to be bonded 200 is a ceramic copper-clad substrate, a metallized substrate, or a heat dissipation substrate. A 4D-printed responsive functional intermediate layer 300 has a thermally enhanced region 330 below the active area or high heat flux density area of ​​the chip, and a stress buffer 340 at the chip edge. The thermally enhanced region 330 contains aluminum nitride, diamond micron powder, silicon carbide, or sheet-like boron nitride filler; the stress buffer 340 contains a low-modulus thermally responsive polymer or a pore gradient elastomer. During bonding, the thermally enhanced region 330 forms a through or quasi-through thermal conduction path under pressure, while the stress buffer 340 absorbs the thermal expansion mismatch deformation between the ceramic substrate and the chip. This example is particularly suitable for power packaging scenarios that require simultaneous reduction of interfacial thermal resistance and thermal cycling stress.

[0061] Example 6: A three-dimensional stacked package or heterogeneous integrated package. For example... Figure 6 As shown, when multiple chips, memory chips, logic chips, RF chips, or sensor chips are stacked along the thickness direction, 4D-printed responsive functional intermediate layers 300 can be set at different interfaces. A thermally enhanced region 330 with a higher filler content is set at the interface near the high heat flux chip; a low-modulus stress buffer zone 340 is set at the interface near the edge of a thin or brittle chip; a conductive bonding region 320 is set at the location of a redistribution port or micro-bump array; and conductive crack monitoring lines are set at the stack edges or easily delaminated areas. Monitoring signals for each layer can be extracted through external test pads or internal test channels, thereby continuously monitoring the interface health status during the bonding and service stages.

[0062] To further demonstrate the technical effectiveness of this invention, finite element simulation or process comparison experiments can be used for verification. In one comparison scheme, a traditional uniform conductive adhesive layer is set as a comparative example, and the functionally graded intermediate layer of the 4D printed invention is set as an example. Under the same warpage height, the same pad array, and the same bonding pressure, the interface void ratio, maximum equivalent stress, and contact resistance dispersion are compared, as shown in Table 1. Simulation evaluation can select residual gap in the interface concave region, maximum shear stress at the chip edge, pressure uniformity in the pad region, and thermal resistance of the heat conduction path as indicators. Process evaluation can select the percentage of void area in scanning acoustic microscopy, standard deviation of four-probe contact resistance, peel length after thermal cycling, and monitoring signal stabilization time as indicators. The above indicators show that the advantages of this invention come from the synergy of on-demand partitioned printing, stimulus response compensation, and in-situ monitoring feedback, rather than a single material replacement.

[0063] Table 1: Comparison of Functional Differences Between Traditional Uniform Bonding Layers and the Solution of the Invention

[0064] In some alternative embodiments, the 4D-printed responsive functional intermediate layer can be directly printed on the surface of the first component 100 to be bonded, or it can be printed on a temporary carrier and then transferred to the bonding interface; the conductive bonding region 320 can be printed first and then the stress buffer zone 340 can be printed, or multiple nozzles can be used for simultaneous printing; the response can be triggered by thermal stimulation, or by light, electric field, magnetic field or pressure; bonding can be completed using open-loop parameters, or closed-loop control can be performed using the output signal of the sensing monitoring region 350. As long as its core is still to form a multi-material partitioned responsive functional intermediate layer within the chip packaging bonding interface through 4D printing, and to utilize the time evolution function of this intermediate layer to achieve warpage compensation, interconnection, heat dissipation, stress release or monitoring feedback, it falls within the technical concept scope of this invention.

[0065] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A chip packaging adaptive bonding structure based on a 4D printing responsive functional intermediate layer, characterized in that, The system includes a first component to be bonded, a second component to be bonded, and a 4D-printed responsive functional intermediate layer disposed between the first and second components. The 4D-printed responsive functional intermediate layer includes a responsive matrix material, and functional fillers and bonding active components embedded in or partitioned within the responsive matrix material. The responsive matrix material is used to generate a preset deformation, volume change, modulus change, or shape recovery under external stimuli. The functional fillers are distributed regionally within the responsive matrix material to form multiple functional zones. The functional zones include at least two of the following: conductive bonding zones, thermally enhanced zones, stress buffer zones, deformation compensation zones, insulating isolation zones, and sensing monitoring zones.

2. The chip packaging adaptive bonding structure based on a 4D printing responsive functional intermediate layer according to claim 1, characterized in that, Multiple functional zones are arranged side-by-side in the planar direction, layered in the thickness direction, or together form a three-dimensional gradient distribution in the planar and thickness directions; at least one functional zone has a thickness, porosity, equivalent elastic modulus, conductive filler content, thermally conductive filler content, or stimulus response threshold that are different from those of adjacent functional zones.

3. The chip packaging adaptive bonding structure based on a 4D printing responsive functional intermediate layer according to claim 1, characterized in that, The conductive bonding region is set for the pads, microbumps, metal pillars, or redistribution ports of the first and second components to be bonded; the thermally enhanced region is set for the chip heat source projection area or the high heat flux density area of ​​the power device, and the thermally enhanced region forms a preferred heat conduction path along the thickness direction, radial direction, or heat source to heat dissipation substrate direction; the stress buffer is set at the chip edge, the corner of the adapter board, the area prone to interface peeling, the periphery of the MEMS sensitive structure, or the thermal expansion mismatch area, and the equivalent elastic modulus of the stress buffer is lower than the equivalent elastic modulus of the conductive bonding region or the thermally enhanced region; the deformation compensation region is set for the local low-recessed area, warped area, pad height difference area, or roughness difference area of ​​the interface to be bonded, and has an initial thickness, porosity, shape recovery amount, thermal expansion response amount, and / or pressure-induced flow capability greater than the adjacent area.

4. The chip packaging adaptive bonding structure based on a 4D printing responsive functional intermediate layer according to claim 1, characterized in that, The sensing and monitoring area includes an in-situ monitoring unit formed synchronously during the 4D printing process. The in-situ monitoring unit includes a piezoresistive sensing grid, a capacitive sensing unit, a thermistor unit, a conductive crack monitoring line, a bridge strain unit, or a combination thereof, used to collect pressure, temperature, strain, resistance, capacitance, and / or interface integrity signals during the bonding process. The in-situ monitoring unit is formed in the same multi-material printing process as the response matrix material and the functional filler, and the output signal of the in-situ monitoring unit corresponds to the deformation, modulus change, local gap change, and / or conductive phase connection state of the response matrix material.

5. A chip packaging adaptive bonding method based on a 4D-printed responsive functional intermediate layer, used to implement the chip packaging adaptive bonding structure based on a 4D-printed responsive functional intermediate layer as described in any one of claims 1 to 4, characterized in that, Includes the following steps: The surface morphology, warpage state, interconnection position, and thermo-mechanical parameters of the first component to be bonded and the second component to be bonded are obtained; based on the obtained surface morphology, warpage state, interconnection position, and thermo-mechanical parameters, the interface to be bonded is divided into multiple functional regions; A multi-material printing path is generated based on multiple functional regions, and the 4D printed responsive functional intermediate layer is prepared with a printing accuracy of no more than 50 micrometers in positioning error. The 4D printed responsive functional intermediate layer is pre-cured, pre-crosslinked, pre-sintered, or pre-shaped to maintain the printed pattern and retain its ability to respond to subsequent stimuli. Align the first and second components to be bonded and apply pre-pressure; apply heat, pressure, electric field, light, magnetic field or a combination thereof to cause the 4D printed responsive functional intermediate layer to undergo preset deformation, modulus change, release of bonding active components, connection of conductive phase, formation of thermal conductive pathways and / or curing reaction.

6. The chip packaging adaptive bonding method based on a 4D-printed responsive functional intermediate layer according to claim 5, characterized in that, The surface morphology and the warping state are obtained by white light interferometry, laser profilometry, confocal microscopy, wafer warping measurement or three-dimensional profile reconstruction, respectively. The target thickness, target modulus and target response displacement of the 4D printed responsive functional intermediate layer at each coordinate position are determined based on the target bonding gap, allowable interface stress and pad position matrix.

7. The chip packaging adaptive bonding method based on a 4D-printed responsive functional intermediate layer according to claim 5, characterized in that, The pre-curing, pre-crosslinking, pre-sintering, or pre-shaping processes are performed at temperatures ranging from 40°C to 160°C for 30 seconds to 30 minutes. When photocuring is used for pretreatment, the photocuring energy density is 50 mJ / cm². 2 Up to 2000mJ / cm 2 Furthermore, the degree of curing after pretreatment is lower than that of the fully cured state.

8. The chip packaging adaptive bonding method based on a 4D-printed responsive functional intermediate layer according to claim 5, characterized in that, The bonding temperature during the adaptive bonding process is 60°C to 250°C, the bonding pressure is 0.05MPa to 30MPa, and the holding time is 1 second to 60 minutes; wherein, when the second component to be bonded is an organic packaging substrate or a flexible substrate, the bonding temperature is 60°C to 180°C.

9. The chip packaging adaptive bonding method based on a 4D-printed responsive functional intermediate layer according to claim 5, characterized in that, The sensing and monitoring area collects pressure, temperature, strain, resistance, or capacitance signals of the interface to be bonded. When the local pressure is lower than a preset threshold, the local bonding temperature is increased, the holding time is extended, or the bonding pressure is increased. When the local pressure is higher than the preset threshold, the bonding pressure is reduced, the heating rate is reduced, or the local heating path is adjusted. The sampling frequency of the sensing and monitoring area is 10Hz to 1kHz. When the rate of change of the contact resistance of the conductive bonding area is less than 5% over at least 10 consecutive sampling periods, and the pressure, capacitance, or strain signals meet the uniformity condition, the bonding is considered complete.

10. A chip packaging device, characterized in that, The chip packaging adaptive bonding structure based on a 4D-printed responsive functional intermediate layer as described in any one of claims 1 to 4 is a chip-integrated packaging device, a wafer-level packaging device, a three-dimensional stacked packaging device, a glass adapter plate packaging device, a MEMS sensor packaging device, a power electronics packaging device, a radio frequency packaging device, or a heterogeneous integrated packaging device.

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